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Sample records for absorption depth profile

  1. Absorption depth profile of water on thermoplastic starch films

    SciTech Connect

    Bonno, B.; Laporte, J.L.; Paris, D.; D'Leon, R.T.

    2000-01-01

    It is well known that petroleum derived polymers are primary environmental contaminants. The study of new packing biodegradable materials has been the object of numerous papers in past years. Some of these new materials are the thermoplastic films derived from wheat starch. In the present paper, the authors study some of properties of wheat starch thermoplastic films, with various amounts of absorbed water, using photoacoustic spectroscopy techniques. The absorption depth profile of water in the starch substrate is determined for samples having a variable water level.

  2. Optical absorption depth profiling of photodegraded poly(vinylchloride) (PVC) films by quantitative photothermal deflection technique

    NASA Astrophysics Data System (ADS)

    Fu, S.-W.; Power, J. F.; Nepotchatykh, O. V.

    2000-05-01

    An improved photothermal beam deflection technique is applied for optical absorption depth profiling of UV photodegraded PVC films, for nondestructive evaluation of their decomposition mechanism. A new model-based on diffraction theory is used to describe the photothermal response (with bicell recording), induced by impulse irradiation of a depth dependent array of thin planar optical absorbers approximating the sample's depth profile. Improved techniques of alignment, sample preparation and quantitative deconvolution of the bicell impulse response have increased the signal repeatability and reduced the principal bias errors affecting this ill posed problem. By this technique and a stable solution of the inverse problem, the absorption coefficient depth profile is accurately reconstructed in PVC films. Experimental depth profiles were confirmed against destructive techniques run on identical samples of the degraded material. An excellent agreement was found between depth profiles recovered using the mirage effect and these reference methods. Observed absorption profiles were fully consistent with known patterns of depth dependent PVC degradation under nitrogen and oxygen atmospheres.

  3. Spectral Absorption Depth Profile: A Step Forward to Plasmonic Solar Cell Design

    NASA Astrophysics Data System (ADS)

    Hossain, Mohammad K.; Mukhaimer, Ayman W.; Drmosh, Qasem A.

    2016-07-01

    Absorption depth profile, a deterministic and key factor that defines the quality of excitons generation rate in optoelectronic devices, is numerically predicted using finite different time domain analysis. A typical model, nanoparticles array on silicon slab, was devised considering the concept of plasmonic solar cell design. The trend of spectral absorption depth profile distributions at various wavelengths of the solar spectrum, 460 nm, 540 nm, 650 nm, 815 nm, and 1100 nm, was obtained. A stronger and well-distributed absorption profile was obtained at ˜650 nm of the solar spectrum (i.e. ˜1.85 eV, c-Si bandgap), although the absorbing layer was affected more than a half micron depth at shorter wavelengths. Considering the observations obtained from this simulation, we have shown a simple two-step method in fabricating ultra-pure silver (Ag) nanoparticles that can be used as plasmonic nanoscatterers in a thin film solar cell. The morphology and elemental analysis of as-fabricated Ag nanoparticles was confirmed by field emission scanning electron microscope (FESEM) and FESEM-coupled electron diffraction spectroscopy. The size of the as-fabricated Ag nanoparticles was found to range from 50 nm to 150 nm in diameter. Further investigations on structural and optical properties of the as-fabricated specimen were carried out using ultraviolet-visible (UV-Vis) absorption, photoluminesce, and x-ray diffraction (XRD). Preferential growth of ZnO along {002} was confirmed by XRD pattern that was more intense and broadened at increasing annealing temperatures. The lattice parameter c was found to increase, whereas grain size increased with increasing annealing temperature. The optical bandgap was also observed to decrease from 3.31 eV to 3.25 eV at increasing annealing temperatures through UV-Vis measurements. This parallel investigation on optical properties by simulation is in line with experimental studies and, in fact, facilitates devising optimum process cost for

  4. The Global Ozone and Aerosol Profiles and Aerosol Hygroscopic Effect and Absorption Optical Depth (GOA2HEAD) Network Initiative

    NASA Astrophysics Data System (ADS)

    Gao, R. S.; Elkins, J. W.; Frost, G. J.; McComiskey, A. C.; Murphy, D. M.; Ogren, J. A.; Petropavlovskikh, I. V.; Rosenlof, K. H.

    2014-12-01

    Inverse modeling using measurements of ozone (O3) and aerosol is a powerful tool for deriving pollutant emissions. Because they have relatively long lifetimes, O3 and aerosol are transported over large distances. Frequent and globally spaced vertical profiles rather than ground-based measurements alone are therefore highly desired. Three requirements necessary for a successful global monitoring program are: Low equipment cost, low operation cost, and reliable measurements of known uncertainty. Conventional profiling using aircraft provides excellent data, but is cost prohibitive on a large scale. Here we describe a new platform and instruments meeting all three global monitoring requirements. The platform consists of a small balloon and an auto-homing glider. The glider is released from the balloon at about 5 km altitude, returning the light instrument package to the launch location, and allowing for consistent recovery of the payload. Atmospheric profiling can be performed either during ascent or descent (or both) depending on measurement requirements. We will present the specifications for two instrument packages currently under development. The first measures O3, RH, p, T, dry aerosol particle number and size distribution, and aerosol optical depth. The second measures dry aerosol particle number and size distribution, and aerosol absorption coefficient. Other potential instrument packages and the desired spatial/temporal resolution for the GOA2HEAD monitoring initiative will also be discussed.

  5. Oxygen depth profiling with subnanometre depth resolution

    NASA Astrophysics Data System (ADS)

    Kosmata, Marcel; Munnik, Frans; Hanf, Daniel; Grötzschel, Rainer; Crocoll, Sonja; Möller, Wolfhard

    2014-10-01

    A High-depth Resolution Elastic Recoil Detection (HR-ERD) set-up using a magnetic spectrometer has been taken into operation at the Helmholtz-Zentrum Dresden-Rossendorf for the first time. This instrument allows the investigation of light elements in ultra-thin layers and their interfaces with a depth resolution of less than 1 nm near the surface. As the depth resolution is highly influenced by the experimental measurement parameters, sophisticated optimisation procedures have been implemented. Effects of surface roughness and sample damage caused by high fluences need to be quantified for each kind of material. Also corrections are essential for non-equilibrium charge state distributions that exist very close to the surface. Using the example of a high-k multilayer SiO2/Si3N4Ox/SiO2/Si it is demonstrated that oxygen in ultra-thin films of a few nanometres thickness can be investigated by HR-ERD.

  6. Vertical Profiles of Light Scattering, Light Absorption, and Single Scattering Albedo during the Dry, Biomass Burning Season in Southern Africa and Comparisons of In Situ and Remote Sensing Measurements of Aerosol Optical Depths

    NASA Technical Reports Server (NTRS)

    Magi, Brian I.; Hobbs, Peter V.; Schmid, Beat; Redermann, Jens

    2003-01-01

    Airborne in situ measurements of vertical profiles of aerosol light scattering, light absorption, and single scattering albedo (omega (sub 0)) are presented for a number of locations in southern Africa during the dry, biomass burning season. Features of the profiles include haze layers, clean air slots, and marked decreases in light scattering in passing from the boundary layer into the free troposphere. Frequency distributions of omega (sub 0) reflect the strong influence of smoke from biomass burning. For example, during a period when heavy smoke was advected into the region from the north, the mean value of omega (sub 0) in the boundary layer was 0.81 +/- 0.02 compared to 0.89 +/- 0.03 prior to this intrusion. Comparisons of layer aerosol optical depths derived from the in situ measurements with those measured by a Sun photometer aboard the aircraft show excellent agreement.

  7. Depth profile characterization with noncollinear beam mixing

    SciTech Connect

    Freed, Shaun L. E-mail: jeong.na@wyle.com; Na, Jeong K. E-mail: jeong.na@wyle.com

    2015-03-31

    Noncollinear beam mixing is an ultrasonic approach to quantify elastic nonlinearity within a subsurface volume of material. The technique requires interaction between two beams of specific frequency, angle, and vibration mode to generate a third beam propagating from the intersection volume. The subsurface depth to interaction zone is controlled by changing the separation distance between the two input transducers, and the amplitude of the third generated beam is proportional to the elastic nonlinearity within the interaction zone. Therefore, depth profiling is possible if a suitable parameter is established to normalize the detected signal independent of propagation distances and input amplitudes. This foundational effort has been conducted toward developing such a parameter for depth profile measurements in homogeneous aluminum that includes corrective terms for attenuation, beam overlap noise, beam spread, and input amplitudes. Experimental and analytical results are provided, and suggested applications and improvements are discussed toward characterizing subsurface material property profiles.

  8. Molecular Depth Profiling by Wedged Crater Beveling

    PubMed Central

    Mao, Dan; Lu, Caiyan; Winograd, Nicholas; Wucher, Andreas

    2011-01-01

    Time-of-flight secondary ion mass spectrometry and atomic force microscopy are employed to characterize a wedge-shaped crater eroded by a 40keV C60+ cluster ion beam on an organic film of Irganox 1010 doped with Irganox 3114 delta layers. From an examination of the resulting surface, the information about depth resolution, topography and erosion rate can be obtained as a function of crater depth for every depth in a single experiment. It is shown that when measurements are performed at liquid nitrogen temperature, a constant erosion rate and reduced bombardment induced surface roughness is observed. At room temperature, however, the erosion rate drops by ~1/3 during the removal of the 400 nm Irganox film and the roughness gradually increased to from 1 nm ~4 nm. From SIMS lateral images of the beveled crater and AFM topography results, depth resolution was further improved by employing glancing angles of incidence and lower primary ion beam energy. Sub-10 nm depth resolution was observed under the optimized conditions on a routine basis. In general, we show that the wedge-crater beveling is an important tool for elucidating the factors that are important for molecular depth profiling experiments. PMID:21744861

  9. VAPID: Voigt Absorption-Profile [Interstellar] Dabbler

    NASA Astrophysics Data System (ADS)

    Howarth, Ian D.

    2015-06-01

    VAPID (Voigt Absorption Profile [Interstellar] Dabbler) models interstellar absorption lines. It predicts profiles and optimizes model parameters by least-squares fitting to observed spectra. VAPID allows cloud parameters to be optimized with respect to several different data set simultaneously; those data sets may include observations of different transitions of a given species, and may have different S/N ratios and resolutions.

  10. Oxygen depth profiling by nuclear resonant scattering

    SciTech Connect

    Gibson, G. T.; Sheu, W. J.; Glass, G. A.; Wang, Y. Q.

    1999-06-10

    Nuclear resonance scattering (NRS) {sup 16}O({alpha},{alpha}){sup 16}O at 3.045 MeV ({gamma}=10 keV) has been used for oxygen depth profiling in various thin oxide films. There are two ways by which the oxygen concentration versus depth profile can be obtained from the experimental data: energy spectrum simulation or yield distribution analysis. Energy spectrum simulation is done using the standard RBS software/Rutherford Universal Manipulation Program (RUMP) where only one spectrum is usually needed from the measurement. Yield distribution analysis is accomplished by using a custom developed software/Resonance Analysis Program (RAP) and involves a series of spectra obtained by stepping up the beam energy above the resonance energy. This article aims at comparing the fundamentals of both methods and also discussing their advantages and disadvantages in terms of the data acquisition and the post data analysis. A thermally grown thick SiO{sub 2} film and a thin titanium oxide film grown by corona point discharge were examined.

  11. Oxygen depth profiling by nuclear resonant scattering

    SciTech Connect

    Gibson, G.T.; Sheu, W.J.; Glass, G.A. Wang, Y.Q.

    1999-06-01

    Nuclear resonance scattering (NRS) {sup 16}O({alpha},{alpha}){sup 16}O at 3.045 MeV ({Gamma}=10&hthinsp;keV) has been used for oxygen depth profiling in various thin oxide films. There are two ways by which the oxygen concentration versus depth profile can be obtained from the experimental data: energy spectrum simulation or yield distribution analysis. Energy spectrum simulation is done using the standard RBS software/Rutherford Universal Manipulation Program (RUMP) where only one spectrum is usually needed from the measurement. Yield distribution analysis is accomplished by using a custom developed software/Resonance Analysis Program (RAP) and involves a series of spectra obtained by stepping up the beam energy above the resonance energy. This article aims at comparing the fundamentals of both methods and also discussing their advantages and disadvantages in terms of the data acquisition and the post data analysis. A thermally grown thick SiO{sub 2} film and a thin titanium oxide film grown by corona point discharge were examined. {copyright} {ital 1999 American Institute of Physics.}

  12. Adsorption depth profile of water on thermoplastic starch films

    SciTech Connect

    Bonno, B.; Laporte, J.L.; Paris, D.; D'Leon, R.T.

    2000-01-01

    It is well known that petroleum derived polymers are primary environmental contaminants. The study of new packing biodegradable materials has been the object of numerous papers in past years. Some of these new materials are the thermoplastic films derived from wheat starch. In the present paper, the authors study some of properties of wheat starch thermoplastic films, with various amounts of absorbed water, using photoacoustic spectroscopy techniques. The absorption depth profile of water in the starch substrate is determined for samples having a variable water level.

  13. Development of neutron depth profiling at CMRR

    NASA Astrophysics Data System (ADS)

    Li, Run-dong; Yang, Xin; Wang, Guan-bo; Dou, Hai-feng; Qian, Da-zhi; Wang, Shu-yu

    2015-07-01

    A neutron depth profiling (NDP) system has been developed at China Mianyang Research Reactor (CMRR) at Institute of Nuclear Physics and Chemistry (INPC), CAEP. The INPC-NDP system utilizes cold neutrons which are transported along the C1 neutron guide from the cold neutron source. It consists of a beam entrance, a target chamber, a beam stopper, and data acquisition electronics for charged particle pulse-height analysis. A 90 cm in diameter stainless steel target chamber was designed to control the positions of the sample and detector. The neutron beam intensity of 2.1×108 n cm-2 s-1 was calibrated by the Au foil activation method at the sample position. The INPC-NDP system was tested by using a Standard Reference Materials SRM-2137. The measured results agreed well with the reference values.

  14. Tritium Depth Profiles in 316 Stainless Steel

    NASA Astrophysics Data System (ADS)

    Torikai, Yuji; Murata, Daiju; Penzhorn, Ralf-Dieter; Akaishi, Kenya; Watanabe, Kuniaki; Matsuyama, Masao

    To investigate the behavior of hydrogen uptake and release by 316 stainless steel (SS316), as-received and finely polished stainless steel specimens were exposed at 573 K to tritium gas diluted with hydrogen. Then tritium concentration in the exposed specimens was measured as a function of depth using a chemical etching method. All the tritium concentration profiles showed a sharp drop in the range of 10 μm from the top surface up to the bulk. The amount of tritium absorbed into the polished specimens was three times larger than that into the as-received specimen. However, the polishing effects disappeared by exposing to the air for a long time.

  15. Mirage effect spectrometry and light profile microscopy: Two views of an optical depth profile (abstract)

    NASA Astrophysics Data System (ADS)

    Power, J. F.; Fu, S. W.; Nepotchatykh, O. V.

    2003-01-01

    Photothermal depth profiling techniques are well adapted for the inspection of optically absorbing features on the length scale of 1-100 μm in a variety of media. However, the depth profiling mechanism intrinsic to thermal wave imaging is inherently ill posed [J. F. Power, AIP Conf. Proc. 463, 3 (1999)], and suffers obvious disadvantages such as sensitivity to experimental errors (requiring regularization) and subsurface broadening of the regularized depth profiles. Recently, through the introduction of light profile microscopy (LPM) an alternate method of optical inspection was made available for depth profiling optically absorbing, scattering, and luminescent structures on this length scale [J. F. Power and S. W. Fu, Appl. Spectros. 53, 1507 (1999); J. F. Power and S. W. Fu, U.S. Patent Pending]. LPM inspects a thin film under test by directing a laser beam through the material along the depth axis, parallel to a polished cross-sectional viewing surface. Luminescence and elastic scatter excited in the beam volume is imaged by a microscope aligned orthogonal to the beam axis. The images obtained by this method showed striking depth contrast in a variety of materials with subsurface interfaces and depth variations of luminescence yield. When implemented in dual beam mode [J. F. Power and S. W. Fu, U.S. Patent Pending; J. F. Power and S. W. Fu, (unpublished)] with an associated mathematical method, LPM may be used to quantitatively resolve depth variable optical absorption from light scattering and luminescence efficiency. In contrast to photothermal methods, the LPM technique is well posed. LPM was evaluated in tandem with mirage effect spectrometry (in normal deflection mode with bicell detection) [J. F. Power, S. W. Fu, and M. A. Schweitzer, Appl. Spectros. 54, 110 (2000)], to determine the effective use of each technique in analysis problems on complex materials. This study used samples with known depth variations of optical properties including homogeneous

  16. Chemical Depth Profiling from Neutron Reflectometry

    SciTech Connect

    Tuncay Aktosun

    2006-03-21

    The material profile of a thin film can be analyzed by placing the film on a substrate and by sending a neutron beam onto it at various angles of incidence. Technically, the scattering length density of the film needs to be determined as a function of depth. A reflectometer is used to measure the amount of reflection (reflectivity) as a function of the angle of incidence. Mathematically, this is equivalent to sending the neutron beam onto the film at every energy but at a fixed angle of incidence. The film profile needs to be recovered from the measured reflectivity data. Unfortunately, the unique recovery is impossible, and many distinct unrelated profiles may correspond to the same reflectivity data. In our DOE/EPSCoR sponsored research, we have developed an analytical method to uniquely recover the profile of a thin film from the measured reflectivity data. We have shown that by taking reflectivity measurements with two different substrates, one can uniquely determine the film profile. Previously, it was known that one could uniquely recover the profile by taking reflectivity measurements with three different substrates, and our findings indicate that the same goal can be accomplished by using fewer measurements. At Mississippi State University we started an informal weekly seminar (called ''the reflectometry meeting'') at to attract various undergraduate and graduate students into the field. There were about 3 undergraduate students, 6 graduate students, and 2 faculty members attending these seminars. The PI has collaborated with Dr. Norm Berk at National Institute of Standards and Technology (NIST) on various aspects of neutron reflectometry, from which various interesting problems of theoretical and practical importance have arisen. One of these problems is closely related to the important mathematical problem known as analytic extrapolation. Under appropriate conditions (known to hold in neutron reflectometry), the reflection data taken in a finite interval

  17. Photothermal determination of thermal diffusivity and polymerization depth profiles of polymerized dental resins

    NASA Astrophysics Data System (ADS)

    Martínez-Torres, P.; Mandelis, A.; Alvarado-Gil, J. J.

    2009-12-01

    The degree and depth of curing due to photopolymerization in a commercial dental resin have been studied using photothermal radiometry. The sample consisted of a thick layer of resin on which a thin metallic gold layer was deposited, thus guaranteeing full opacity. Purely thermal-wave inverse problem techniques without the interference of optical profiles were used. Thermal depth profiles were obtained by heating the gold coating with a modulated laser beam and by performing a frequency scan. Prior to each frequency scan, photopolymerization was induced using a high power blue light emitted diode (LED). Due to the highly light dispersive nature of dental resins, the polymerization process depends strongly on optical absorption of the blue light, thereby inducing a depth dependent thermal diffusivity profile in the sample. A robust depth profilometric method for reconstructing the thermal diffusivity depth dependence on degree and depth of polymerization has been developed. The thermal diffusivity depth profile was linked to the polymerization kinetics.

  18. Sampling Depths, Depth Shifts, and Depth Resolutions for Bi(n)(+) Ion Analysis in Argon Gas Cluster Depth Profiles.

    PubMed

    Havelund, R; Seah, M P; Gilmore, I S

    2016-03-10

    Gas cluster sputter depth profiling is increasingly used for the spatially resolved chemical analysis and imaging of organic materials. Here, a study is reported of the sampling depth in secondary ion mass spectrometry depth profiling. It is shown that effects of the sampling depth leads to apparent shifts in depth profiles of Irganox 3114 delta layers in Irganox 1010 sputtered, in the dual beam mode, using 5 keV Ar₂₀₀₀⁺ ions and analyzed with Bi(q+), Bi₃(q+) and Bi₅(q+) ions (q = 1 or 2) with energies between 13 and 50 keV. The profiles show sharp delta layers, broadened from their intrinsic 1 nm thickness to full widths at half-maxima (fwhm's) of 8-12 nm. For different secondary ions, the centroids of the measured delta layers are shifted deeper or shallower by up to 3 nm from the position measured for the large, 564.36 Da (C₃₃H₄₆N₃O₅⁻) characteristic ion for Irganox 3114 used to define a reference position. The shifts are linear with the Bi(n)(q+) beam energy and are greatest for Bi₃(q+), slightly less for Bi₅(q+) with its wider or less deep craters, and significantly less for Bi(q+) where the sputtering yield is very low and the primary ion penetrates more deeply. The shifts increase the fwhm’s of the delta layers in a manner consistent with a linearly falling generation and escape depth distribution function (GEDDF) for the emitted secondary ions, relevant for a paraboloid shaped crater. The total depth of this GEDDF is 3.7 times the delta layer shifts. The greatest effect is for the peaks with the greatest shifts, i.e. Bi₃(q+) at the highest energy, and for the smaller fragments. It is recommended that low energies be used for the analysis beam and that carefully selected, large, secondary ion fragments are used for measuring depth distributions, or that the analysis be made in the single beam mode using the sputtering Ar cluster ions also for analysis. PMID:26883085

  19. Quantification of AES depth profiles by the MRI model

    NASA Astrophysics Data System (ADS)

    Kovač, Janez; Zalar, Anton; Praček, Borut

    2003-02-01

    The main physical effects that contribute to interface broadening in the sputter depth profiles of polycrystalline metallic multilayer structures were studied by comparison of measured and simulated AES depth profiles. An algorithm based on the so-called mixing-roughness-information depth (MRI) model was used to simulate AES depth profiles of Ni/Cr multilayer structures with different roughnesses of the initial surfaces. The simulated depth profiles were compared with measurements performed at two different depth profiling parameters on the Ni/Cr and Al/Ni/Cr multilayer structures with an initial surface roughness of about 1.0 and 21.5 nm, respectively. The comparison of simulated and measured depth profiles enabled us to separate and estimate different contributions to the interface broadening, as well as their dependence on the sputter depth. We found that roughness was the dominant factor related to depth resolution with respect to the information depth and atomic mixing contribution. The values of roughness introduced into the simulation algorithm coincided well with the values measured by AFM at the initial surface and after depth profiling. The results showed the capability of the simulation procedure based on the MRI model to separate and evaluate different contributions to the depth resolution.

  20. Non-Voigt Lyalpha Absorption Line Profiles.

    PubMed

    Outram; Carswell; Theuns

    2000-02-01

    Recent numerical simulations have lead to a paradigm shift in our understanding of the intergalactic medium and the loss of a physical justification for Voigt profile fitting of the Lyalpha forest. Many individual lines seen in simulated spectra have significant departures from the Voigt profile, yet could be well fitted by a blend of two or more such lines. We discuss the expected effect on the line profiles due to ongoing gravitational structure formation and Hubble expansion. We develop a method to detect departures from Voigt profiles of the absorption lines in a statistical way and apply this method to simulated Lyalpha forest spectra, confirming that the profiles seen do statistically differ from Voigt profiles. PMID:10622758

  1. Depth profiling of tritium in materials for fusion technology

    SciTech Connect

    Sawicki, J.A.

    1988-09-01

    The paper outlines recent progress in depth profiling of tritium distribution near the surface of materials by two ion beam techniques; elastic recoil detection (ERD) and T(d,/alpha/)n nuclear reaction analysis (NRA). The sensitivity and depth-resolution of both methods are examined for a series of tritiated titanium films. Calculated depth profiles and ranges of implanted tritium ions in selected candidate materials for thermonuclear fusion devices are also given. Depth profiles of tritium implanted into specimens of graphite and lithium oxides as a function of temperature are discussed as the examples of applications.

  2. Neutron depth profiling by large angle coincidence spectroscopy

    SciTech Connect

    Vacik, J.; Cervena, J.; Hnatowicz, V.; Havranek, V.; Fink, D.

    1995-12-31

    Extremely low concentrations of several technologically important elements (mainly lithium and boron) have been studied by a modified neutron depth profiling technique. Large angle coincidence spectroscopy using neutrons to probe solids with a thickness not exceeding several micrometers has proved to be a powerful analytical method with an excellent detection sensitivity. Depth profiles in the ppb atomic range are accessible for any solid material. A depth resolution of about 20 nanometers can be achieved.

  3. Optical and thermal depth profile reconstructions of inhomogeneous photopolymerization in dental resins using photothermal waves

    NASA Astrophysics Data System (ADS)

    Martínez-Torres, P.; Mandelis, A.; Alvarado-Gil, J. J.

    2010-09-01

    Photopolymerization is a process that depends, among other factors, on the optical properties of polymerized materials. In turn, this process affects longitudinal light transport in these materials, thereby altering their optical absorption coefficient which is thus expected to exhibit depth dependence. Furthermore, polymerization affects the thermal properties of these materials. A robust theoretical approach to the study of the depth-dependent optical absorption coefficient, β(x ), and thermal diffusivity, α(x ), in materials exhibiting depth profiles of these parameters has been developed through the photothermal inverse problem based on the concept of the thermal-harmonic oscillator. Using this concept in the frequency-domain nonhomogeneous photothermal-wave boundary-value problem, the simultaneous reconstruction of arbitrary simultaneous optical and thermal depth profiles was achieved using a multiparameter fitting method to the experimental amplitude and phase. As a first application of the theory to partially polymerized Alert Composite (shade A3) dental resin, with curing induced by a blue light-emitting diode, the β(x ) and α(x ) depth profiles were reconstructed from photothermal radiometric frequency-scanned data. A strong anticorrelation of these two depth profiles was observed and was interpreted in terms of photochemical processes occurring during the optical (photocuring) creation of long polymeric chains in the resin. The photothermally reconstructed depth profiles may have implications for the optimization of blue light curing methods using such resins in dental clinical practice.

  4. Analytical and numerical depth resolution functions in sputter profiling

    NASA Astrophysics Data System (ADS)

    Hofmann, S.; Liu, Y.; Wang, J. Y.; Kovac, J.

    2014-09-01

    Quantification of sputter depth profiles is frequently done by fitting the convolution integral over concentration and depth resolution function to the experimental results. For a thin delta layer, there exist analytical solutions. The analytical depth resolution functions of two popular approaches, that of the Mixing-Roughness-Information depth (MRI) model and that of Dowsett and coworkers are compared. It is concluded that the analytical depth resolution function of the MRI model gives the correct location of a buried delta layer with respect to the measured profile, and a clear description of the information depth in AES, XPS and SIMS. Both analytical solutions can be extended to larger layer thickness. But they are less flexible with respect to physical parameters which are not constant with concentration or sputtered depth, such as detection sensitivity, atomic mixing or preferential sputtering. For these cases, numerical solutions have to be used.

  5. Depth-selective X-ray absorption spectroscopy by detection of energy-loss Auger electrons

    NASA Astrophysics Data System (ADS)

    Isomura, Noritake; Soejima, Narumasa; Iwasaki, Shiro; Nomoto, Toyokazu; Murai, Takaaki; Kimoto, Yasuji

    2015-11-01

    A unique X-ray absorption spectroscopy (XAS) method is proposed for depth profiling of chemical states in material surfaces. Partial electron yield mode detecting energy-loss Auger electrons, called the inelastic electron yield (IEY) mode, enables a variation in the probe depth. As an example, Si K-edge XAS spectra for a well-defined multilayer sample (Si3N4/SiO2/Si) have been investigated using this method at various kinetic energies. We found that the peaks assigned to the layers from the top layer to the substrate appeared in the spectra in the order of increasing energy loss relative to the Auger electrons. Thus, the probe depth can be changed by the selection of the kinetic energy of the energy loss electrons in IEY-XAS.

  6. Influence of non-Gaussian roughness on sputter depth profiles

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Jian, W.; Wang, J. Y.; Hofmann, S.; Kovac, J.

    2013-07-01

    Surface/interface roughness has a significant influence on the shape of the depth profile measured by any depth profiling technique. Such an influence is particularly significant for thin delta layers and at sharp interfaces of single- and multilayers. In the mixing-roughness-information (MRI) model for quantification of measured depth profiles, the influence of roughness is usually taken into account by a Gaussian height distribution function (HDF). If the roughness cannot be represented by a Gaussian HDF, a non-Gaussian HDF has to be implemented into the MRI model. Deviations of simulated depth profiles using the MRI model with Gaussian and with several well-defined non-Gaussian HDFs are evaluated quantitatively. The results indicate that a realistic non-Gaussian HDF has to be taken into account if high accuracy in quantification of sputter depth profiles is required. Of particular importance is the case of a roughness given by an asymmetrical HDF. Application of an asymmetrical triangle height distribution function in the MRI model yields an excellent fit for the measured AES depth profiling data of a polycrystalline Al film.

  7. Bevel Depth Profiling SIMS for Analysis of Layer Structures

    NASA Astrophysics Data System (ADS)

    Gillen, Greg; Wight, Scott; Chi, Peter; Fahey, Albert; Verkouteren, Jennifer; Windsor, Eric; Fenner, D. B.

    2003-09-01

    We are evaluating the use of bevel depth profiling Secondary Ion Mass Spectrometry (SIMS) for the characterization of layered semiconductor materials. In this procedure, a sub-degree angle bevel is cut into the analytical sample with an oxygen or cesium primary ion beam in a commercial SIMS instrument. The elemental distribution of the resulting bevel surface is then imaged with a focused ion beam in the same instrument. This approach offers maximum flexibility for depth profiling analysis. The primary beam energy, incident angle and species used to cut the bevel can be optimized to minimize ion beam mixing and surface topography independent of the conditions used for secondary ion analysis. In some cases, depth resolution can be greater than available from conventional depth profiling. Removal of residual surface damage/topography created during beveling has also been investigated by the cleaning of the bevel surfaces using gas-cluster ion beam sputtering before imaging analysis.

  8. Sensitivity of depth of maximum and absorption depth of EAS to hadron production mechanism

    NASA Technical Reports Server (NTRS)

    Antonov, R. A.; Ivanenko, I. P.; Kanevsky, B. L.; Kuzmin, V. A.; Galkin, V. I.; Hein, L. A.

    1985-01-01

    Comparison of experimental data on depth of extensive air showers (EAS) development maximum in the atmosphere, T sub M and path of absorption, lambda, in the lower atmosphere of EAS with fixed particle number in the energy region eV with the results of calculation show that these parameters are sensitive mainly to the inelastic interaction cross section and scaling violation in the fragmentation and pionization region. The data are explained in a unified manner within the framework of a model in which scaling is violated slightly in the fragmentation region and strongly in the pionization region at primary cosmic rays composition close to the normal one and a permanent increase of inelastic interaction cross section. It is shown that, while interpreting the experimental data, disregard of two methodical points causes a systematic shift in T sub M: (1) shower selection system; and (2) EAS electron lateral distribution when performing the calculations on basis of which the transfer is made from the Cerenkov pulse FWHM to the depth of shower maximum, T sub M.

  9. Development and Applications of Time of Flight Neutron Depth Profiling

    SciTech Connect

    Bingham Cady; Kenan Unlu

    2005-03-17

    The depth profiles of intentional or intrinsic constituents of a sample provide valuable information for the characterization of materials. For example, the subtle differences in spatial distribution and composition of many chemical species in the near surface region and across interfacial boundaries can significantly alter the electronic and optical properties of materials. A number of analytical techniques for depth profiling have been developed during the last two decades. neutron Depth Profiling (NDP) is one of the leading analytical techniques. The NDP is a nondestructive near surface technique that utilizes thermal/cold neutron beam to measure the concentration of specific light elements versus their depth in materials. The depth is obtained from the energy loss of protons, alphas or recoil atoms in substrate materials. Since the charged particle energy determination using surface barrier detector is used for NDP, the depth resolution is highly dependent on the detectors an d detection instruments. The depth resolutions of a few tens of nm are achieved with available NDP facilities in the world. However, the performance of NDP needs to be improved in order to obtain a few A depth resolutions.

  10. Neutron depth profiling: Overview and description of NIST facilities

    SciTech Connect

    Downing, R.G.; Lamaze, G.P.; Langland, J.K.; Hwang, S.T.

    1993-01-01

    The Cold Neutron Depth Profiling (CNDP) instrument at the NIST Cold Neutron Research Facility (CNRF) is now operational. The neutron beam originates from a 16 L D2O ice cold source and passes through a filter of 135 mm of single crystal sapphire. The neutron energy spectrum may be described by a 65 K Maxwellian distribution. The sample chamber configuration allows for remote controlled scanning of 150 x 150 mm sample areas including the varying of both sample and detector angle. The improved sensitivity over the current thermal depth profiling instrument has permitted the first nondestructive measurements of (17)O profiles. The paper describes the CNDP instrument, illustrates the neutron depth profiling (NDP) technique with examples, and gives a separate bibliography of NDP publications.

  11. Photothermal radiometric determination of thermal diffusivity depth profiles in a dental resin

    NASA Astrophysics Data System (ADS)

    Martínez-Torres, P.; Mandelis, A.; Alvarado-Gil, J. J.

    2010-03-01

    The depth of curing due to photopolymerization in a commercial dental resin is studied using photothermal radiometry. The sample consists of a thick layer of resin on which a thin metallic layer is deposited guaranteeing full opacity of the sample. In this case, purely thermal-wave inverse problem techniques without the interference of optical profiles can be used. Thermal profiles are obtained by heating the coating with a modulated laser beam and performing a modulation frequency scan. Before each frequency scan, photopolymerization was induced using a high power blue LED. However due to the fact that dental resins are highly light dispersive materials, the polymerization process depends strongly on the optical absorption coefficient inducing a depth dependent thermal diffusion in the sample. It is shown that using a robust depth profilometric inverse method one can reconstruct the thermal diffusivity profile of the photopolymerized resin.

  12. Cluster SIMS and the Temperature Dependence of Molecular Depth Profiles

    PubMed Central

    Mao, Dan; Wucher, Andreas; Brenes, Daniel A; Lu, Caiyan; Winograd, Nicholas

    2012-01-01

    The quality of molecular depth profiles created by erosion of organic materials by cluster ion beams exhibits a strong dependence upon temperature. To elucidate the fundamental nature of this dependence, we employ the Irganox 3114/1010 organic delta layer reference material as a model system. This delta-layer system is interrogated using a 40 keV C60+ primary ion beam. Parameters associated with the depth profile such as depth resolution, uniformity of sputtering yield and topography are evaluated between 90 K and 300 K using a unique wedge-crater beveling strategy that allows these parameters to be determined as a function of erosion depth from atomic force microscope measurements. The results show that the erosion rate calibration performed using the known Δ-layer depth in connection with the fluence needed to reach the peak of the corresponding SIMS signal response is misleading. Moreover, we show that the degradation of depth resolution is linked to a decrease of the average erosion rate and the buildup of surface topography in a thermally activated manner. This underlying process starts to influence the depth profile above a threshold temperature between 210 and 250 K for the system studied here. Below that threshold, the process is inhibited and steady-state conditions are reached with constant erosion rate, depth resolution and molecular secondary ion signals from both the matrix and the Δ-layers. In particular, the results indicate that further reduction of the temperature below 90 K does not lead to further improvement of the depth profile. Above the threshold, the process becomes stronger at higher temperature, leading to an immediate decrease of the molecular secondary ion signals. This signal decay is most pronounced for the highest m/z ions but is less for the smaller m/z ions, indicating a shift toward small fragments by accumulation of chemical damage. The erosion rate decay and surface roughness buildup, on the other hand, exhibit a rather sudden

  13. Absorption Line Profiles for 39 Rapidly Rotating Stars

    NASA Astrophysics Data System (ADS)

    Stoeckley, T. R.; Carroll, R. W.; Miller, R. D.

    1984-05-01

    Absorption lines of He II, HeI, MgII and other ions have been measured in 169 photographic coude spectra for 39 rapidly rotating B-type stars on the main sequence. All 1500 separate line profiles have been analysed with a procedure of differential corrections by least-squares to yield the following parameters and their error estimates: half-width, central depth, equivalent width and shape parameter. The shape parameter includes Voigt profiles and also `super-Gaussian' and `super-damping' profiles. Up to 15 separately measured line profiles in each star have been superimposed to yield better composite profiles with point scatter as small as 0.5 per cent. In addition, a preliminary value of V sin i is derived for each line of each star, and a mean value (including error bars) is derived for each star. Results are compared and discussed, with reference to forthcoming work incorporating stellar distortion, gravity darkening, and other second-order effects, which will allow determinations of axial inclination and differential rotation of individual stars, using the data sets presented here and elsewhere.

  14. Molecular sputter depth profiling using carbon cluster beams

    PubMed Central

    Winograd, Nicholas

    2010-01-01

    Sputter depth profiling of organic films while maintaining the molecular integrity of the sample has long been deemed impossible because of the accumulation of ion bombardment-induced chemical damage. Only recently, it was found that this problem can be greatly reduced if cluster ion beams are used for sputter erosion. For organic samples, carbon cluster ions appear to be particularly well suited for such a task. Analysis of available data reveals that a projectile appears to be more effective as the number of carbon atoms in the cluster is increased, leaving fullerene ions as the most promising candidates to date. Using a commercially available, highly focused C60q+ cluster ion beam, we demonstrate the versatility of the technique for depth profiling various organic films deposited on a silicon substrate and elucidate the dependence of the results on properties such as projectile ion impact energy and angle, and sample temperature. Moreover, examples are shown where the technique is applied to organic multilayer structures in order to investigate the depth resolution across film-film interfaces. These model experiments allow collection of valuable information on how cluster impact molecular depth profiling works and how to understand and optimize the depth resolution achieved using this technique. PMID:19649771

  15. Crack depth profiling using guided wave angle dependent reflectivity

    SciTech Connect

    Volker, Arno Pahlavan, Lotfollah Blacquiere, Gerrit

    2015-03-31

    Tomographic corrosion monitoring techniques have been developed, using two rings of sensors around the circumference of a pipe. This technique is capable of providing a detailed wall thickness map, however this might not be the only type of structural damage. Therefore this concept is expanded to detect and size cracks and small corrosion defects like root corrosion. The expanded concept uses two arrays of guided-wave transducers, collecting both reflection and transmission data. The data is processed such that the angle-dependent reflectivity is obtained without using a baseline signal of a defect-free situation. The angle-dependent reflectivity is the input of an inversion scheme that calculates a crack depth profile. From this profile, the depth and length of the crack can be determined. Preliminary experiments show encouraging results. The depth sizing accuracy is in the order of 0.5 mm.

  16. Total ozone and aerosol optical depths inferred from radiometric measurements in the Chappuis absorption band

    SciTech Connect

    Flittner, D.E.; Herman, B.M.; Thome, K.J.; Simpson, J.M.; Reagan, J.A. )

    1993-04-15

    A second-derivative smoothing technique, commonly used in inversion work, is applied to the problem of inferring total columnar ozone amounts and aerosol optical depths. The application is unique in that the unknowns (i.e., total columnar ozone and aerosol optical depth) may be solved for directly without employing standard inversion methods. It is shown, however, that by employing inversion constraints, better solutions are normally obtained. The current method requires radiometric measurements of total optical depth through the Chappuis ozone band. It assumes no a priori shape for the aerosol optical depth versus wavelength profile and makes no assumptions about the ozone amount. Thus, the method is quite versatile and able to deal with varying total ozone and various aerosol size distributions. The technique is applied first in simulation, then to 119 days of measurements taken in Tucson, Arizona, that are compared to TOMS values for the same dates. The technique is also applied to two measurements taken at Mauna Loa, Hawaii, for which Dobson ozone values are available in addition to the TOMS values, and the results agree to within 15%. It is also shown through simulations that additional information can be obtained from measurements outside the Chappuis band. This approach reduces the bias and spread of the estimates total ozone and is unique in that it uses measurements from both the Chappuis and Huggins absorption bands. 12 refs., 6 figs., 2 tabs.

  17. Optothermal skin pigment spectral depth profiling using an OPO laser

    NASA Astrophysics Data System (ADS)

    Xiao, Peng; Guo, Xinxin; Notingher, Ioan; Cowen, Anna J.; O'Driscoll, Don; Imhof, Robert E.

    1999-06-01

    This paper presents the results of a research program to quantify the factors that determine the visual appearance of human skin. We use in-vivo opto-thermal transient emission radiometry (OTTER) with a tunable OPO laser (400 - 590 nm) to measure spectrally resolved pigment depth profiles. Radiation in this wavelength range is only weakly absorbed by stratum corneum and epidermis, but strongly absorbed by sub-surface pigments, mainly melanin and haemoglobin. These produce characteristic delayed thermal wave (DTW) signals, detected using a high speed Mercury Cadmium Telluride detector sensitive in the wavelength range 6 - 13 microns. The measured intensity-time profiles yield the desired concentration depth profiles through either model-based non-linear least-squares analysis or model-independent inverse analysis. Results on melanin and haemoglobin distributions within normal, tape stripped and wash-damaged skin are presented.

  18. Depth Profiles in Maize ( Zea mays L.) Seeds Studied by Photoacoustic Spectroscopy

    NASA Astrophysics Data System (ADS)

    Hernández-Aguilar, C.; Domínguez-Pacheco, A.; Cruz-Orea, A.; Zepeda-Bautista, R.

    2015-06-01

    Photoacoustic spectroscopy (PAS) has been used to analyze agricultural seeds and can be applied to the study of seed depth profiles of these complex samples composed of different structures. The sample depth profile can be obtained through the photoacoustic (PA) signal, amplitude, and phase at different light modulation frequencies. The PA signal phase is more sensitive to changes of thermal properties in layered samples than the PA signal amplitude. Hence, the PA signal phase can also be used to characterize layers at different depths. Thus, the objective of the present study was to obtain the optical absorption spectra of maize seeds ( Zea mays L.) by means of PAS at different light modulation frequencies (17 Hz, 30 Hz, and 50 Hz) and comparing these spectra with the ones obtained from the phase-resolved method in order to separate the optical absorption spectra of seed pericarp and endosperm. The results suggest the possibility of using the phase-resolved method to obtain optical absorption spectra of different seed structures, at different depths, without damaging the seed. Thus, PAS could be a nondestructive method for characterization of agricultural seeds and thus improve quality control in the food industry.

  19. On the origins of C IV absorption profile diversity in broad absorption line quasars

    NASA Astrophysics Data System (ADS)

    Baskin, Alexei; Laor, Ari; Hamann, Fred

    2015-05-01

    There is a large diversity in the C IV broad absorption line (BAL) profile among BAL quasars (BALQs). We quantify this diversity by exploring the distribution of the C IV BAL properties, full width at half-maximum (FWHM), maximum depth of absorption and its velocity shift (vmd), using the Sloan Digital Sky Survey DR7 quasar catalogue. We find the following: (i) Although the median C IV BAL profile in the quasar rest-frame becomes broader and shallower as the UV continuum slope (αUV at 1700-3000 Å) gets bluer, the median individual profile in the absorber rest-frame remains identical, and is narrow (FWHM = 3500 km s-1) and deep. Only 4 per cent of BALs have FWHM > 10 000 km s-1. (ii) As the He II emission equivalent width (EW) decreases, the distributions of FWHM and vmd extend to larger values, and the median maximum depth increases. These trends are consistent with theoretical models in which softer ionizing continua reduce overionization, and allow radiative acceleration of faster BAL outflows. (iii) As αUV becomes bluer, the distribution of vmd extends to larger values. This trend may imply faster outflows at higher latitudes above the accretion disc plane. (iv) For non-BALQs, the C IV emission line decreases with decreasing He II EW, and becomes more asymmetric and blueshifted. This suggests an increasing relative contribution of emission from the BAL outflow to the C IV emission line as the ionizing spectral energy distribution (SED) gets softer, which is consistent with the increasing fraction of BALQs as the ionizing SED gets softer.

  20. Mars Sample Return: The Value of Depth Profiles

    NASA Technical Reports Server (NTRS)

    Hausrath, E. M.; Navarre-Sitchler, A. K.; Moore, J.; Sak, P. B.; Brantley, S. L.; Golden, D. C.; Sutter, B.; Schroeder, C.; Socki, R.; Morris, R. V.; Ming, D. W.

    2008-01-01

    Sample return from Mars offers the promise of data from Martian materials that have previously only been available from meteorites. Return of carefully selected samples may yield more information about the history of water and possible habitability through Martian history. Here we propose that samples collected from Mars should include depth profiles of material across the interface between weathered material on the surface of Mars into unweathered parent rock material. Such profiles have the potential to yield chemical kinetic data that can be used to estimate the duration of water and information about potential habitats on Mars.

  1. Ion-beam depth-profiling studies of leached glasses

    SciTech Connect

    Houser, C.A.; Tsong, I.S.T.; White, W.B.; Wintenberg, A.L.; Miller, P.D.; Moak, C.D.

    1981-01-01

    Ion-beam depth-profiling was carried out on three different glasses leached (or hydrated) in deionized water using /sup 1/H(/sup 19/F,..cap alpha gamma..)/sup 16/O nuclear reaction, secondary ion mass spectrometry (SIMS) and sputter-induced photon spectrometry (SIPS) techniques. The depth-profiles show an interdiffusion mechanism in which the sodium ions in the glass are depleted and replaced by hydrogen (H/sup +/) or hydronium (H/sub 3/O/sup +/) ions from the solution. The leaching behavior does not show significant difference whether the glass surface is fractured or polished. Problems of mobile ion migration caused by ion bombardment and loss of hydrogen during analysis are discussed.

  2. Depth profiles and free volume in aircraft primer films

    NASA Astrophysics Data System (ADS)

    Van Horn, J. D.; Chen, H.; Jean, Y. C.; Zhang, W.; Jaworowski, M. R.

    2015-06-01

    Positron annihilation lifetime spectroscopy (PALS) and associated techniques provide non-destructive methods to study the free volume inside polymeric materials, and to study material characteristics over a depth profile. Cast free films of organic- or aqueous-based, non-chromated aerospace primers, when cured for about one week, had very different water vapour transport (through-plane) behaviour. In addition, both types of primer films showed strong anisotropic behaviour in in-plane versus through-plane water vapour transport rates. We report the differences between the organic- and aqueous-based aircraft primer films samples and their surface depth profiles. In bulk PALS measurements, an aged, organic-based film exhibited typical lifetimes and intensities for a particulate-containing polymer film on both faces. In contrast, aqueous-based films exhibited face oriented-dependent differences. In all aqueous- based samples, the I3 value of the back of the sample was smaller. The primer film samples were also evaluated with mono-energetic positron beam techniques to generate depth profile information. The heterogeneity in the samples was verified by Doppler broadening of energy spectroscopy (DBES). A model for the differences in the faces of the films, and their layered structure is discussed.

  3. On optical depth profiling using confocal Raman spectroscopy.

    PubMed

    Freebody, N A; Vaughan, A S; Macdonald, A M

    2010-04-01

    Until 2006 the performance of confocal Raman spectroscopy depth profiling was typically described and modeled through the application of geometrical optics, including refraction at the surface, to explain the degree of resolution and the precise form of the depth profile obtained from transparent and semicrystalline materials. Consequently a range of techniques, physical and analytical, was suggested to avoid the errors thus encountered in order to improve the practice of Raman spectroscopy, if not the understanding of the underlying mechanisms. These approaches were completely unsuccessful in accounting for the precise form of the depth profile, the fact that spectra obtained from laminated samples always contain characteristic peaks from all materials present both well above and below the focal point and that spectra can be obtained when focused some 40 mum above the sample surface. This paper provides further evidence that the physical processes underlying Raman spectroscopy are better modeled and explained through the concept of an extended illuminated volume contributing to the final Raman spectrum and modeled through a photon scattering approach rather than a point focus ray optics approach. The power of this numerical model lies in its ability to incorporate, simultaneously, the effects of degree of refraction at the surface (whether using a dry or oil objective lens), the degree of attenuation due to scatter by the bulk of the material, the Raman scattering efficiency of the material, and surface roughness effects. Through this we are now able to explain why even removing surface aberration and refraction effects through the use of oil immersion objective lenses cannot reliably ensure that the material sampled is only that at or close to the point of focus of the laser. Furthermore we show that the precise form of the depth profile is affected by the degree of flatness of the surface of the sample. Perhaps surprisingly, we show that the degree of flatness

  4. Pulsed photothermal depth profiling of tattoos undergoing laser removal treatment

    NASA Astrophysics Data System (ADS)

    Milanic, Matija; Majaron, Boris

    2012-02-01

    Pulsed photothermal radiometry (PPTR) allows noninvasive determination of temperature depth profiles induced by pulsed laser irradiation of strongly scattering biological tissues and organs, including human skin. In present study, we evaluate the potential of this technique for investigational characterization and possibly quantitative evaluation of laser tattoo removal. The study involved 5 healthy volunteers (3 males, 2 females), age 20-30 years, undergoing tattoo removal treatment using a Q-switched Nd:YAG laser. There were four measurement and treatment sessions in total, separated by 2-3 months. Prior to each treatment, PPTR measurements were performed on several tattoo sites and one nearby healthy site in each patient, using a 5 ms Nd:YAG laser at low radiant exposure values and a dedicated radiometric setup. The laser-induced temperature profiles were then reconstructed by applying a custom numerical code. In addition, each tatoo site was documented with a digital camera and measured with a custom colorimetric system (in tristimulus color space), providing an objective evaluation of the therapeutic efficacy to be correlated with our PPTR results. The results show that the laser-induced temperature profile in untreated tattoos is invariably located at a subsurface depth of 300 μm. In tattoo sites that responded well to laser therapy, a significant drop of the temperature peak was observed in the profiles obtained from PPTR record. In several sites that appeared less responsive, as evidenced by colorimetric data, a progressive shift of the temperature profile deeper into the dermis was observed over the course of consecutive laser treatments, indicating that the laser tattoo removal was efficient.

  5. Depth profiles of D and T in Metal-hydride films up to large depth

    NASA Astrophysics Data System (ADS)

    Zhang, HongLiang; Ding, Wei; Su, Ranran; Zhang, Yang; Shi, Liqun

    2016-03-01

    In this paper, a method combining D(3He, p) 4He nuclear reaction and proton backscattering (PBS) was adopted to detect the depth profile of both D and T in TiDxTy/Mo film with thickness more than 5 μm. Different energies of 3He and proton beam, varied from 1.0 to 3.0 MeV and 1.5 to 3.8 MeV respectively, were used in order to achieve better depth resolution. With carefully varying incident energies, an optimum resolution of less than 0.5 μm for D and T distribution throughout the whole analyzed range could be achieved.

  6. Studying Velocity Turbulence from Doppler-broadened Absorption Lines: Statistics of Optical Depth Fluctuations

    SciTech Connect

    Lazarian, A.; Pogosyan, D.

    2008-10-10

    We continue our work on developing techniques for studying turbulence with spectroscopic data. We show that Doppler-broadened absorption spectral lines, in particular, saturated absorption lines, can be used within the framework of the previously introduced technique termed the velocity coordinate spectrum (VCS). The VCS relates the statistics of fluctuations along the velocity coordinate to the statistics of turbulence; thus, it does not require spatial coverage by sampling directions in the plane of the sky. We consider lines with different degree of absorption and show that for lines of optical depth less than one, our earlier treatment of the VCS developed for spectral emission lines is applicable, if the optical depth is used instead of intensity. This amounts to correlating the logarithms of absorbed intensities. For larger optical depths and saturated absorption lines, we show that only wings of the line are available for the analysis. In terms of the VCS formalism, this results in introducing an additional window, whose size decreases with the increase of the optical depth. As a result, strongly saturated absorption lines only carry the information about the small-scale turbulence. Nevertheless, the contrast of the fluctuations corresponding to the small-scale turbulence increases with the increase of the optical depth, which provides advantages for studying turbulence by combining lines with different optical depths. By combining different absorption lines one can develop a tomography of the turbulence in the interstellar gas in all its complexity.

  7. Relationship between smoking and periodontal probing pocket depth profile.

    PubMed

    Adler, Lottie; Modin, Carolina; Friskopp, Johan; Jansson, Leif

    2008-01-01

    The purpose of the present study was to investigate if the periodontal probing pocket depth profile differs significantly between smokers and non-smokers as well as within the smoking group. Subjects born 1940-1943 were collected from a computer database at a specialist clinic of periodontology. The patients included consisted of 293 individuals between 57 and 64years of age examined by nine periodontists. The periodontal probing depth at site level, age, gender and smoking habits were collected from the database. Former smokers and patients with an uncertain history of smoking habits were excluded. The smokers were stratified into three groups according to the daily consumption of cigarettes (1-10 cig/day, 11-20 cig/day, > 20 cig/day). The relative frequencies of periodontal probing pocket depths of 4-5 mm and > or = 6 mm were calculated and these two categories were used in the analyses. The partial correlation coefficients between smoking and the percentage share of periodontal pocket depths in different tooth regions were calculated by using multiple regression analyses. The smokers had significantly deeper periodontal pockets compared to the nonsmokers. The correlation between smoking and the percentage share of palatal periodontal pockets > or = 6 mm was significant. The percentage share of palatal pockets > or = 6 mm was significantly increased for subjects who smoked > 20 cigarettes per day (25%) compared to non-smokers as well as compared to subjects with a daily consumption of 1-20 cigarettes per day. This difference was significant within all tooth groups in the upper jaw. The results support the hypothesis that smoking has a local effect on periodontal pocket depth beside the systemic effect. PMID:19172916

  8. Neutron depth profiling at the University of Texas

    NASA Astrophysics Data System (ADS)

    Ünlü, Kenan; Wehring, Bernard W.

    1994-12-01

    A Neutron Depth Profiling (NDP) facility has been developed at The University of Texas at Austin (UT) Nuclear Engineering Teaching Laboratory. Thermal neutrons from the tangential beam port of the UT 1-MW TRIGA Mark II research reactor are utilized. The UT-NDP facility consists of a neutron beam collimator, target chamber, beam catcher, and necessary data acquisition and process electronics. The collimator was designed to achieve a high quality thermal neutron beam with good intensity and minimum contamination of neutrons above thermal energies. A target chamber for NDP was constructed from 40.6 cm diameter aluminum tubing. The chamber can accommodate several small samples as well as a single large sample with a diameter up to 30.5 cm. Depth profiles for borophosphosilicate glass films on silicon wafers were measured using the UT-NDP facility. Other potential applications of the UT-NDP facility include the study of implanted boron in semiconductor material; study of nitrogen in metals; and study of helium behavior in metals, and metallic and amorphous alloys.

  9. Cold neutron depth profiling of lithium-ion battery materials

    NASA Astrophysics Data System (ADS)

    Lamaze, G. P.; Chen-Mayer, H. H.; Becker, D. A.; Vereda, F.; Goldner, R. B.; Haas, T.; Zerigian, P.

    We report the characterization of two thin-film battery materials using neutron techniques. Neutron depth profiling (NDP) has been employed to determine the distribution of lithium and nitrogen simultaneously in lithium phosphorous oxynitride (LiPON) deposited by ion beam assisted deposition (IBAD). The depth profiles are based on the measurement of the energy of the charged particle products from the 6Li(n,α) 3H and 14N(n,p) 14C reactions for lithium and nitrogen, respectively. Lithium at the level of 10 22 atoms/cm 3 and N of 10 21 atoms/cm 3, distributed in the film thickness on the order of 1 μm, have been determined. This information provides insights into nitrogen incorporation and lithium concentration in the films under various fabrication conditions. NDP of lithium has also been performed on IBAD LiCoO 2 films, in conjunction with instrumental neutron activation analysis (INAA) to determine the cobalt concentration. The Li/Co ratio thus obtained serves as an ex situ control for the thin-film evaporation process. The non-destructive nature of the neutron techniques is especially suitable for repeated analysis of these materials and for actual working devices.

  10. SIMS depth profiling of polymer blends with protein based drugs

    NASA Astrophysics Data System (ADS)

    Mahoney, Christine M.; Yu, Jinxiang; Fahey, Albert; Gardella, Joseph A.

    2006-07-01

    We report the results of the surface and in-depth characterization of two component blend films of poly( L-lactic acid) (PLLA) and Pluronic surfactant [poly(ethylene oxide) (A) poly(propylene oxide) (B) ABA block copolymer]. These blend systems are of particular importance for protein drug delivery, where it is expected that the Pluronic surfactant will retain the activity of the protein drug and enhance the biocompatibility of the device. Angle dependant X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) employing an SF 5+ polyatomic primary ion source were both used for monitoring the surfactant's concentration as a function of depth. The results show an increased concentration of surfactant at the surface, where the surface segregation initially increases with increasing bulk concentration and then remains constant above 5% (w/w) Pluronic. This surface segregated region is immediately followed by a depletion region with a homogeneous mixture in the bulk of the film. These results suggest the selection of the surfactant bulk concentration of the thin film matrices for drugs/proteins delivery should achieve a relatively homogeneous distribution of stabilizer/protein in the PLLA matrix. Analysis of three component blends of PLLA, Pluronic and insulin are also investigated. In the three component blends, ToF-SIMS imaging shows the spatial distribution of surfactant/protein mixtures. These data are reported also as depth profiles.

  11. The relativistic Doppler broadening of the line absorption profile

    NASA Astrophysics Data System (ADS)

    Kichenassamy, S.; Krikorian, R.; Nikogosian, A.

    1982-06-01

    The classical results of Doppler broadening of the line absorption profile are generalized to a relativistic gas in thermal equilibrium by taking into account the relativistic variance of the volume absorption coefficients of the gas, as derived by L. H. Thomas. This variance produces a small correction, even in the non-relativistic approximation.

  12. Depth profile characterization of ultra shallow junction implants.

    PubMed

    Hönicke, Philipp; Beckhoff, Burkhard; Kolbe, Michael; Giubertoni, Damiano; van den Berg, Jaap; Pepponi, Giancarlo

    2010-04-01

    A need for analysis techniques, complementary to secondary ion mass spectrometry (SIMS), for depth profiling dopants in silicon for ultra shallow junction (USJ) applications in CMOS technologies has recently emerged following the difficulties SIMS is facing there. Grazing incidence X-ray fluorescence (GIXRF) analysis in the soft X-ray range is a high-potential tool for this purpose. It provides excellent conditions for the excitation of the B-K and the As-L(iii,ii) shells. The X-ray standing wave (XSW) field associated with GIXRF on flat samples is used here as a tunable sensor to obtain information about the implantation profile because the in-depth changes of the XSW intensity are dependent on the angle of incidence. This technique is very sensitive to near-surface layers and is therefore well suited for the analysis of USJ distributions. Si wafers implanted with either arsenic or boron at different fluences and implantation energies were used to compare SIMS with synchrotron radiation-induced GIXRF analysis. GIXRF measurements were carried out at the laboratory of the Physikalisch-Technische Bundesanstalt (PTB) at the electron storage ring BESSY II using monochromatized undulator radiation of well-known radiant power and spectral purity. The use of an absolutely calibrated energy-dispersive detector for the acquisition of the B-Kalpha and As-Lalpha fluorescence radiation enabled the absolute determination of the total retained dose. The concentration profile was obtained by ab initio calculation and comparison with the angular measurements of the X-ray fluorescence. PMID:19941133

  13. Chemical depth profiling of photovoltaic backsheets after accelerated laboratory weathering

    NASA Astrophysics Data System (ADS)

    Lin, Chiao-Chi; Krommenhoek, Peter J.; Watson, Stephanie S.; Gu, Xiaohong

    2014-10-01

    Polymeric multilayer backsheets provide protection for the backside of photovoltaic (PV) module from the damage of moisture and ultraviolet (UV). Due to the nature of multilayer films, certain material property characterization of a backsheet could only be studied by examining its cross-section parallel to the thickness direction of the film. In this study, commercial PPE (polyethylene terephthalate (PET)/PET/ethylene vinyl acetate (EVA)) backsheet films were aged on the NIST (National Institute of Standards and Technology) SPHERE (Simulated Photodegradation via High Energy Radiant Exposure) with UV irradiance at 170 W/m2 (300 nm to 400 nm) under accelerated weathering conditions of 85°C and two relative humidity (R.H.) levels of 5% (low) and 60% (high). Cryo-microtomy was used to obtain cross-sectional PPE samples with a flat surface parallel to the thickness direction, and chemical depth profiling of multilayers was conducted by Raman microscopic mapping. Atomic force microscopy with peak force tapping mode was used complementarily for cross-sectional imaging. The results revealed that the PPE backsheet films were comprised of five main layers, including pigmented-PET, core PET, inner EVA, pigmented-EVA and outer EVA, along with their interfacial regions and two adhesive layers. UV and moisture degradation on the outer pigmented PET layer was clearly observed; while the damage on the core PET layer was less significance, indicating that the outer pigmented PET layer effectively reduced the damage from UV. In high R.H. exposure, both adhesive layers were severely deteriorated. It was found that the EVA layers were susceptible to moisture at elevated temperature, especially for the pigmented-EVA. Based on the results of accelerated weathering, this depth profiling study brings new understanding to the mechanisms of failure observed in polymeric multilayer backsheets during field exposure.

  14. Absorption spectra and light penetration depth of normal and pathologically altered human skin

    NASA Astrophysics Data System (ADS)

    Barun, V. V.; Ivanov, A. P.; Volotovskaya, A. V.; Ulashchik, V. S.

    2007-05-01

    A three-layered skin model (stratum corneum, epidermis, and dermis) and engineering formulas for radiative transfer theory are used to study absorption spectra and light penetration depths of normal and pathologically altered skin. The formulas include small-angle and asymptotic approximations and a layer-addition method. These characteristics are calculated for wavelengths used for low-intensity laser therapy. We examined several pathologies such as vitiligo, edema, erythematosus lupus, and subcutaneous wound, for which the bulk concentrations of melanin and blood vessels or tissue structure (for subcutaneous wound) change compared with normal skin. The penetration depth spectrum is very similar to the inverted blood absorption spectrum. In other words, the depth is minimal at blood absorption maxima. The calculated absorption spectra enable the power and irradiation wavelength providing the required light effect to be selected. Relationships between the penetration depth and the diffuse reflectance coefficient of skin (unambiguously expressed through the absorption coefficient) are analyzed at different wavelengths. This makes it possible to find relationships between the light fields inside and outside the tissue.

  15. Interstellar Medium Absorption Profile Spectrograph (IMAPS)

    NASA Technical Reports Server (NTRS)

    Jenkins, E. B.

    1985-01-01

    The design and fabrication of an objective-grating echelle spectrograph to fly on sounding rockets and record spectra of stars from approximately 920 to 1120A with a resolving power lambda/delta lambda = 200,000 is discussed. The scientific purpose of the program is to observe, with ten times better velocity resolution than before, the plentiful absorption lines in this spectral region produced by atoms, ions and molecules in the interstellar medium. In addition, an important technical goal is to develop and flight-quality a new ultraviolet, photon-counting image sensor which has a windowless, opaque photocathode and a CCD bombarded directly by the accelerated photoelectrons. Except for some initial difficulties with the performance of CCDs, the development of the payload instrument is relatively straightforward and our overall design goals are satisfied. The first flight occurred in late 1984, but no data were obtained because of an inrush of air degraded the instrument's vacuum and caused the detector's high voltage to arc. A second flight in early 1985 was a complete success and obtained a spectrum of pi Sco. Data from this mission are currently being reduced; quick-look versions of the spectra indicate that excellent results will be obtained. Currently, the payload is being reconfigured to fly on a Spartan mission in 1988.

  16. Trace element depth profiles in presolar silicon carbide grains

    NASA Astrophysics Data System (ADS)

    King, Ashley J.; Henkel, Torsten; Rost, Detlef; Lyon, Ian C.

    2012-10-01

    We have analyzed eleven presolar SiC grains from the Murchison meteorite using time-of-flight secondary ion mass spectrometry. The Si isotopic compositions of the grains indicate that they are probably of an AGB star origin. The average abundances of Mg, Fe, Ca, Al, Ti, and V are strongly influenced by their condensation behavior into SiC in circumstellar environments. Depth profiles of Li, B, Mg, Al, K, Ca, Ti, V, Cr, and Fe in the SiC grains show that trace elements are not always homogenously distributed. In approximately half of the SiC grains studied here, the trace element distributions can be explained by condensation processes around the grains' parent stars. These grains appear to have experienced only minimal processing before their arrival in the presolar molecular cloud, possibly due to short residence times in the interstellar medium. The remaining SiC grains contained elevated abundances of several elements within their outer 200 nm, which is attributed to the implantation of energetic ions accelerated by shockwaves in the interstellar medium. These grains may have spent a longer period of time in this region, hence increasing the probability of them passing through a shockfront. Distinct groups of presolar SiC grains whose residence times in the interstellar medium differ are consistent with previous findings based on noble gas studies, although some grains may also have been shielded from secondary alteration by protective outer mantles.

  17. Depth profiling of polymer films with grazing-incidence small-angle X-ray scattering

    PubMed Central

    Singh, Marsha A.; Groves, Michael N.

    2009-01-01

    A model-free method of reconstructing depth-specific lateral scattering from incident-angle-resolved grazing-incidence small-angle X-ray scattering (GISAXS) data is proposed. The information on the material which is available through variation of the X-ray penetration depth with incident angle is accessed through reference to the reflected branch of the GISAXS process. Reconstruction of the scattering from lateral density fluctuations is achieved by solving the resulting Fredholm integral equation with minimal a priori information about the experimental system. Results from simulated data generated for hypothetical multilayer polymer systems with constant absorption coefficient are used to verify that the method can be applied to cases with large X-ray penetration depths, as typically seen with polymer materials. Experimental tests on a spin-coated thick film of a blend of diblock copolymers demonstrate that the approach is capable of reconstruction of the scattering from a multilayer structure with the identification of lateral scattering profiles as a function of sample depth. PMID:19349663

  18. Techniques for Improving SIMS Depth Resolution: C{sub 60}{sup +} Primary Ions and Backside Depth Profile Analysis

    SciTech Connect

    Windsor, Eric; Gillen, Greg; Bright, David; Chi, Peter; Fahey, Albert; Batteas, James

    2005-09-09

    We are evaluating methods to improve depth resolution for SIMS analyses of semiconductors. Two methods that show promise are: (1) backside depth profile analysis and (2) the use of cluster primary ion beams. Backside analysis improves depth resolution by eliminating sample-induced artifacts caused by sputtering through processing layers on the front side of the wafer. Mechanical backside sample preparation however, also introduces artifacts. The most troublesome artifact is inclined (non-planar) polishing. Using a combination of both secondary ion image depth profiling and image analysis techniques, the effects of inclined polishing are minimized. A Buckminsterfullerene C{sub 60}{sup +} primary ion source has been interfaced to a magnetic sector SIMS instrument for the purpose of depth profile analysis. Application of this source to NIST SRM 2135a (nickel/ chromium multilayer depth profile standard) demonstrated that all layers of this standard were completely resolved. Initial applications of C{sub 60}{sup +} to silicon have produced some unexpected results that are not completely understood at this time. Research is underway to evaluate the application of C{sub 60}{sup +} primary ions to silicon semiconductors and other materials of interest.

  19. Hardness depth profiling of case hardened steels using a three-dimensional photothermal technique

    NASA Astrophysics Data System (ADS)

    Qu, Hong; Wang, Chinhua; Guo, Xinxin; Mandelis, Andreas

    2010-03-01

    A method of retrieving thermophysical depth profiles of continuously inhomogeneous materials is presented both theoretically and experimentally using the three-dimensional (3-D) photothermal radiometry. A 3-D theoretical model suitable for characterizing solids with arbitrary continuously varying thermophysical property depth profiles and finite (collimated or focused) laser beam spotsize is developed. A numerical fitting algorithm to retrieve the thermophysical profile was demonstrated with three case hardened steel samples. The reconstructed thermal conductivity depth profiles were found to be well anti-correlated with microhardness profiles obtained with the conventional indenter method.

  20. A GAS TEMPERATURE PROFILE BY INFRARED EMISSION-ABSORPTION SPECTROSCOPY

    NASA Technical Reports Server (NTRS)

    Buchele, D. R.

    1994-01-01

    This computer program calculates the temperature profile of a flame or hot gas. Emphasis is on profiles found in jet engine or rocket engine exhaust streams containing water vapor or carbon dioxide as radiating gases. The temperature profile is assumed to be axisymmetric with a functional form controlled by two variable parameters. The parameters are calculated using measurements of gas radiation at two wavelengths in the infrared spectrum. Infrared emission and absorption measurements at two or more wavelengths provide a method of determining a gas temperature profile along a path through the gas by using a radiation source and receiver located outside the gas stream being measured. This permits simplified spectral scanning of a jet or rocket engine exhaust stream with the instrumentation outside the exhaust gas stream. This program provides an iterative-cyclic computation in which an initial assumed temperature profile is altered in shape until the computed emission and absorption agree, within specified limits, with the actual instrument measurements of emission and absorption. Temperature determination by experimental measurements of emission and absorption at two or more wavelengths is also provided by this program. Additionally, the program provides a technique for selecting the wavelengths to be used for determining the temperature profiles prior to the beginning of the experiment. By using this program feature, the experimenter has a higher probability of selecting wavelengths which will result in accurate temperature profile measurements. This program provides the user with a technique for determining whether this program will be sufficiently accurate for his particular application, as well as providing a means of finding the solution. The input to the program consists of four types of data: (1) computer program control constants, (2) measurements of gas radiance and transmittance at selected wavelengths, (3) tabulations from the literature of gas

  1. Towards quantitative atmospheric water vapor profiling with differential absorption lidar.

    PubMed

    Dinovitser, Alex; Gunn, Lachlan J; Abbott, Derek

    2015-08-24

    Differential Absorption Lidar (DIAL) is a powerful laser-based technique for trace gas profiling of the atmosphere. However, this technique is still under active development requiring precise and accurate wavelength stabilization, as well as accurate spectroscopic parameters of the specific resonance line and the effective absorption cross-section of the system. In this paper we describe a novel master laser system that extends our previous work for robust stabilization to virtually any number of multiple side-line laser wavelengths for the future probing to greater altitudes. In this paper, we also highlight the significance of laser spectral purity on DIAL accuracy, and illustrate a simple re-arrangement of a system for measuring effective absorption cross-section. We present a calibration technique where the laser light is guided to an absorption cell with 33 m path length, and a quantitative number density measurement is then used to obtain the effective absorption cross-section. The same absorption cell is then used for on-line laser stabilization, while microwave beat-frequencies are used to stabilize any number of off-line lasers. We present preliminary results using ∼300 nJ, 1 μs pulses at 3 kHz, with the seed laser operating as a nanojoule transmitter at 822.922 nm, and a receiver consisting of a photomultiplier tube (PMT) coupled to a 356 mm mirror. PMID:26368258

  2. Spectral variation of the infrared absorption coefficient in pulsed photothermal profiling of biological samples.

    PubMed

    Majaron, Boris; Verkruysse, Wim; Tanenbaum, B Samuel; Milner, Thomas E; Nelson, J Stuart

    2002-06-01

    Pulsed photothermal radiometry can be used for non-invasive depth profiling of optically scattering samples, including biological tissues such as human skin. Computational reconstruction of the laser-induced temperature profile from recorded radiometric signals is sensitive to the value of the tissue absorption coefficient in the infrared detection band (muIR). While assumed constant in reported reconstruction algorithms, muIR of human skin varies by two orders of magnitude in the commonly used 3-5 microm detection band. We analyse the problem of selecting the effective absorption coefficient value to be used with such algorithms. In a numerical simulation of photothermal profiling we demonstrate that results can be markedly impaired, unless the reconstruction algorithm is augmented by accounting for spectral variation muIR(lambda). Alternatively, narrowing the detection band to 4.5-5 microm reduces the spectral variation muIR(lambda) to a level that permits the use of the simpler, unaugmented algorithm. Implementation of the latter approach for depth profiling of port wine stain birthmarks in vivo is presented and discussed. PMID:12108776

  3. Measuring depth profiles of residual stress with Raman spectroscopy

    SciTech Connect

    Enloe, W.S.; Sparks, R.G.; Paesler, M.A.

    1988-12-01

    Knowledge of the variation of residual stress is a very important factor in understanding the properties of machined surfaces. The nature of the residual stress can determine a part`s susceptibility to wear deformation, and cracking. Raman spectroscopy is known to be a very useful technique for measuring residual stress in many materials. These measurements are routinely made with a lateral resolution of 1{mu}m and an accuracy of 0.1 kbar. The variation of stress with depth; however, has not received much attention in the past. A novel technique has been developed that allows quantitative measurement of the variation of the residual stress with depth with an accuracy of 10nm in the z direction. Qualitative techniques for determining whether the stress is varying with depth are presented. It is also demonstrated that when the stress is changing over the volume sampled, errors can be introduced if the variation of the stress with depth is ignored. Computer aided data analysis is used to determine the depth dependence of the residual stress.

  4. ADEPT: a program to estimate depth to magnetic basement from sampled magnetic profiles

    USGS Publications Warehouse

    Phillips, Jeffrey D.

    1978-01-01

    A fortran program computes depth to magnetic basement from the spatially varying autocorrelation function of a sampled magnetic profile. The depth calculation assumes a particular form for the autocorrelation function, and this assumption is tested against the measured autocorrelation function in order to reject invalid depth estimates.

  5. Photothermal depth profiling: Comparison between genetic algorithms and thermal wave backscattering (abstract)

    NASA Astrophysics Data System (ADS)

    Li Voti, R.; Sibilia, C.; Bertolotti, M.

    2003-01-01

    Photothermal depth profiling has been the subject of many papers in the last years. Inverse problems on different kinds of materials have been identified, classified, and solved. A first classification has been done according to the type of depth profile: the physical quantity to be reconstructed is the optical absorption in the problems of type I, the thermal effusivity for type II, and both of them for type III. Another classification may be done depending on the time scale of the pump beam heating (frequency scan, time scan), or on its geometrical symmetry (one- or three-dimensional). In this work we want to discuss two different approaches, the genetic algorithms (GA) [R. Li Voti, C. Melchiorri, C. Sibilia, and M. Bertolotti, Anal. Sci. 17, 410 (2001); R. Li Voti, Proceedings, IV Int. Workshop on Advances in Signal Processing for Non-Destructive Evaluation of Materials, Quebec, August 2001] and the thermal wave backscattering (TWBS) [R. Li Voti, G. L. Liakhou, S. Paoloni, C. Sibilia, and M. Bertolotti, Anal. Sci. 17, 414 (2001); J. C. Krapez and R. Li Voti, Anal. Sci. 17, 417 (2001)], showing their performances and limits of validity for several kinds of photothermal depth profiling problems: The two approaches are based on different mechanisms and exhibit obviously different features. GA may be implemented on the exact heat diffusion equation as follows: one chromosome is associated to each profile. The genetic evolution of the chromosome allows one to find better and better profiles, eventually converging towards the solution of the inverse problem. The main advantage is that GA may be applied to any arbitrary profile, but several disadvantages exist; for example, the complexity of the algorithm, the slow convergence, and consequently the computer time consumed. On the contrary, TWBS uses a simplified theoretical model of heat diffusion in inhomogeneous materials. According to such a model, the photothermal signal depends linearly on the thermal effusivity

  6. Depth profile of uncompensated spins in an exchange bias system

    SciTech Connect

    Roy, S.; Fitzsimmons, M.R.; Park, S.; Dorn, M.; Petracic, O.; Roshchin, Igor V.; Li, Zhi-Pan; Morales, R.; Misra, A.; Zhang, X.; Chesnel, K.; Kortright, J.B.; Sinha, S.K.; Schuller, Ivan K.

    2005-05-17

    We have used the unique spatial sensitivity of polarized neutron and soft x-ray beams in reflection geometry to measure the depth dependence of magnetization across the interface between a ferromagnet and antiferromagnet. The new uncompensated magnetization near the interface responds to applied field, while the uncompensated spins in the antiferromagnetic bulk are pinned, thus providing a means to establish exchange bias.

  7. Residual stress depth profiles of ausrolled 9310 gear steel

    SciTech Connect

    Paliani, C.M.; Queeney, R.A.; Kozaczek, K.J.

    1995-12-31

    Residual Stress analysis utilizing x-ray diffraction in conjunction with material removal by chemical polishing provides a very effective method of analyzing the near surface residual stress profile of steels. In this experiment, residual stress profiling has been used to analyze the effects of surface ausrolling during the marquenching of a 9310 gear steel which has been carburized to 1% carbon. The ausrolling process is an advanced thermomechanical processing technique used to ausform only the critical surface layer of gears and produce a hard, tough, fine-grained martensitic product. This study compares the residual stress profile of a marquenched specimen with a moderately deformed ausrolled specimen and with a heavily deformed ausrolled specimen, in order to correlate the effects of residual stress with the improved fatigue properties of the gear steel. While no significant variation was observed between the residual stress profile of the marquenched specimens (no deformation) and the line contact ausrolled specimens (moderate deformation), significant increases in the amount of compressive residual stress was noted in the residual stress profile of the point contact ausrolled (heavily deformed) samples. The maximum increase in compressive residual stress due to point contact ausrolling was approximately 500 MPa, when compared to the marquenched sample. This increased residual compressive stress will lower the effective shear stresses during rolling contact fatigue and would therefore explain some of the increase the rolling contact fatigue endurance of the point contact ausrolled specimens.

  8. Depth

    PubMed Central

    Koenderink, Jan J; van Doorn, Andrea J; Wagemans, Johan

    2011-01-01

    Depth is the feeling of remoteness, or separateness, that accompanies awareness in human modalities like vision and audition. In specific cases depths can be graded on an ordinal scale, or even measured quantitatively on an interval scale. In the case of pictorial vision this is complicated by the fact that human observers often appear to apply mental transformations that involve depths in distinct visual directions. This implies that a comparison of empirically determined depths between observers involves pictorial space as an integral entity, whereas comparing pictorial depths as such is meaningless. We describe the formal structure of pictorial space purely in the phenomenological domain, without taking recourse to the theories of optics which properly apply to physical space—a distinct ontological domain. We introduce a number of general ways to design and implement methods of geodesy in pictorial space, and discuss some basic problems associated with such measurements. We deal mainly with conceptual issues. PMID:23145244

  9. Hybrid Organic/Inorganic Materials Depth Profiling Using Low Energy Cesium Ions

    NASA Astrophysics Data System (ADS)

    Noël, Céline; Houssiau, Laurent

    2016-02-01

    The structures developed in organic electronics, such as organic light emitting diodes (OLEDs) or organic photovoltaics (OPVs) devices always involve hybrid interfaces, joining metal or oxide layers with organic layers. No satisfactory method to probe these hybrid interfaces physical chemistry currently exists. One promising way to analyze such interfaces is to use in situ ion beam etching, but this requires ion beams able to depth profile both inorganic and organic layers. Mono- or diatomic ion beams commonly used to depth profile inorganic materials usually perform badly on organics, while cluster ion beams perform excellently on organics but yield poor results when organics and inorganics are mixed. Conversely, low energy Cs+ beams (<500 eV) allow organic and inorganic materials depth profiling with comparable erosion rates. This paper shows a successful depth profiling of a model hybrid system made of metallic (Au, Cr) and organic (tyrosine) layers, sputtered with 500 eV Cs+ ions. Tyrosine layers capped with metallic overlayers are depth profiled easily, with high intensities for the characteristic molecular ions and other specific fragments. Metallic Au or Cr atoms are recoiled into the organic layer where they cause some damage near the hybrid interface as well as changes in the erosion rate. However, these recoil implanted metallic atoms do not appear to severely degrade the depth profile overall quality. This first successful hybrid depth profiling report opens new possibilities for the study of OLEDs, organic solar cells, or other hybrid devices.

  10. Hybrid Organic/Inorganic Materials Depth Profiling Using Low Energy Cesium Ions.

    PubMed

    Noël, Céline; Houssiau, Laurent

    2016-05-01

    The structures developed in organic electronics, such as organic light emitting diodes (OLEDs) or organic photovoltaics (OPVs) devices always involve hybrid interfaces, joining metal or oxide layers with organic layers. No satisfactory method to probe these hybrid interfaces physical chemistry currently exists. One promising way to analyze such interfaces is to use in situ ion beam etching, but this requires ion beams able to depth profile both inorganic and organic layers. Mono- or diatomic ion beams commonly used to depth profile inorganic materials usually perform badly on organics, while cluster ion beams perform excellently on organics but yield poor results when organics and inorganics are mixed. Conversely, low energy Cs(+) beams (<500 eV) allow organic and inorganic materials depth profiling with comparable erosion rates. This paper shows a successful depth profiling of a model hybrid system made of metallic (Au, Cr) and organic (tyrosine) layers, sputtered with 500 eV Cs(+) ions. Tyrosine layers capped with metallic overlayers are depth profiled easily, with high intensities for the characteristic molecular ions and other specific fragments. Metallic Au or Cr atoms are recoiled into the organic layer where they cause some damage near the hybrid interface as well as changes in the erosion rate. However, these recoil implanted metallic atoms do not appear to severely degrade the depth profile overall quality. This first successful hybrid depth profiling report opens new possibilities for the study of OLEDs, organic solar cells, or other hybrid devices. PMID:26883532

  11. Hybrid Organic/Inorganic Materials Depth Profiling Using Low Energy Cesium Ions

    NASA Astrophysics Data System (ADS)

    Noël, Céline; Houssiau, Laurent

    2016-05-01

    The structures developed in organic electronics, such as organic light emitting diodes (OLEDs) or organic photovoltaics (OPVs) devices always involve hybrid interfaces, joining metal or oxide layers with organic layers. No satisfactory method to probe these hybrid interfaces physical chemistry currently exists. One promising way to analyze such interfaces is to use in situ ion beam etching, but this requires ion beams able to depth profile both inorganic and organic layers. Mono- or diatomic ion beams commonly used to depth profile inorganic materials usually perform badly on organics, while cluster ion beams perform excellently on organics but yield poor results when organics and inorganics are mixed. Conversely, low energy Cs+ beams (<500 eV) allow organic and inorganic materials depth profiling with comparable erosion rates. This paper shows a successful depth profiling of a model hybrid system made of metallic (Au, Cr) and organic (tyrosine) layers, sputtered with 500 eV Cs+ ions. Tyrosine layers capped with metallic overlayers are depth profiled easily, with high intensities for the characteristic molecular ions and other specific fragments. Metallic Au or Cr atoms are recoiled into the organic layer where they cause some damage near the hybrid interface as well as changes in the erosion rate. However, these recoil implanted metallic atoms do not appear to severely degrade the depth profile overall quality. This first successful hybrid depth profiling report opens new possibilities for the study of OLEDs, organic solar cells, or other hybrid devices.

  12. Computational model to evaluate port wine stain depth profiling using pulsed photothermal radiometry.

    PubMed

    Choi, Bernard; Majaron, Boris; Nelson, J Stuart

    2004-01-01

    We report on development of an optical-thermal model to evaluate the use of pulsed photothermal radiometry (PPTR) for depth profiling of port wine stain (PWS) skin. In the model, digitized histology sections of a PWS biopsy were used as the input skin geometry. Laser induced temperature profiles were reconstructed from simulated PPTR signals by applying an iterative, non-negatively constrained conjugate gradient algorithm. Accuracy of the following PWS skin characteristics extracted from the reconstructed profiles was determined: (1) average epidermal thickness (z(epi)), (2) maximum epidermal temperature rise (DeltaT(epi,max)), (3) depth of PWS upper boundary (z(PWS)), and (4) depth of maximum PWS temperature rise (z(PWS,max)). Comparison of the actual and reconstructed profiles from PPTR data revealed a good match for all four PWS skin characteristics. Results of this study indicate that PPTR is a viable approach for depth profiling of PWS skin. PMID:15065895

  13. Quantitative Analysis of Hemodynamics in Bruised Skin Using Photothermal Depth Profiling

    NASA Astrophysics Data System (ADS)

    Vidovič, L.; Milanič, M.; Majaron, B.

    2015-06-01

    Pulsed photothermal radiometry (PPTR) allows noninvasive measurement of laser-induced temperature depth profiles, providing useful information on depth distribution of specific absorbers in optically scattering biological tissues. In the present study, PPTR profiling is combined with numerical modeling of light transport in human skin to analyze hemoglobin dynamics in traumatic bruises. Specifically, the influence of regularization degree, applied in iterative reconstruction of temperature depth profiles from PPTR signals measured in bruised volunteers, is studied. The results show that selection between two plausible reconstruction results does not significantly affect the assessed values of key bruise evolution parameters, i.e., hemoglobin mass diffusion and characteristic decomposition time.

  14. Al-26 depth profile in Apollo 15 drill core

    NASA Technical Reports Server (NTRS)

    Nishiizumi, K.; Arnold, J. R.; Klein, J.; Middleton, R.

    1984-01-01

    Accelerator mass spectrometry is used in a study of galactic cosmic ray production profiles based on cosmic ray-produced Al-26 in the Apollo 15 long core. The results, which are in general agreement with earlier nondestructive counting data, are of significantly higher precision, yet systematically lower. The half-attenuation length for Al-26 production is presently calculated to be 122 g/sq cm, after normalizing the data to average chemical composition.

  15. Compositional depth profiling of TaCN thin films

    SciTech Connect

    Adelmann, Christoph; Conard, Thierry; Franquet, Alexis; Brijs, Bert; Munnik, Frans; Burgess, Simon; Witters, Thomas; Meersschaut, Johan; Kittl, Jorge A.; Vandervorst, Wilfried; Van Elshocht, Sven

    2012-07-15

    The composition profiling of thin TaCN films was studied. For the composition profile determination using x-ray photoemission spectrometry (XPS) in combination with Ar sputtering, preferential sputtering effects of N with respect to Ta and C were found to lead to inaccurate elemental concentrations. Sputter yield calculations for the given experimental conditions allowed for the correction of a part of the error, leading to fair accuracy by reference-free measurements. Further improvement of the accuracy was demonstrated by the calibration of the XPS compositions against elastic recoil detection analysis (ERDA) results. For Auger electron spectrometry (AES) in combination with Ar sputtering, accurate results required the calibration against ERDA. Both XPS and AES allowed for a reliable and accurate determination of the compositional profiles of TaCN-based thin films after calibration. Time-of-flight secondary-ion mass spectrometry was also used to assess the composition of the TaCN films. However, the analysis was hampered by large matrix effects due to small unintentional oxygen contents in the films. Energy-dispersive x-ray spectrometry is also discussed, and it is shown that an accurate reference-free measurement of the average film concentration can be achieved.

  16. The long-term global record on Aerosol Absorption Optical Depth from TOMS and OMI observations

    NASA Astrophysics Data System (ADS)

    Torres, O.; Bhartia, P.; Ahn, C.; Veefkind, P.

    2006-12-01

    Carbonaceous aerosols from biomass burning and boreal forest fires, and desert dust lofted by the winds from the world major arid and semi-arid areas are among the most long-lived aerosol types in the Earth's atmosphere, since they often reach the free troposphere and are sometimes transported thousands of kilometers from their original sources. A lot has been learned about the global distribution of aerosol sources, and the transport patterns of these aerosol types since the development of the near-UV methods of aerosol detection and characterization using data from the TOMS series of instruments. Because both smoke and desert dust aerosols absorb UV-radiation, the TOMS aerosol sensing technique is specially suited for tracking these aerosol types over variety of surfaces including clouds and snow. TOMS aerosol observations, for instance, have been fundamental in discovering that carbonaceous aerosols associated with wild fires at mid and high latitudes often reach the lower stratosphere, and travel as far as the remote polar regions. We have recently completed the development of an improved algorithm to derive quantitative information about aerosol absorption optical depth using near-UV data. We will discuss the multi- decadal global record on aerosol absorption optical depth produced using TOMS and OMI sensors, and review the multiple contributions of the TOMS-OMI record to the current understanding of the factors that govern the observed temporal and spatial distribution of smoke and desert dust aerosols.

  17. XPS and XRF depth patina profiles of ancient silver coins

    NASA Astrophysics Data System (ADS)

    Caridi, F.; Torrisi, L.; Cutroneo, M.; Barreca, F.; Gentile, C.; Serafino, T.; Castrizio, D.

    2013-05-01

    Ancient silver coins of different historical periods going from IV cent. B.C. up to recent XIX century, coming from different Mediterranean countries have been investigated with different surface physical analyses. X-ray photoelectron spectroscopy (XPS) analysis has been performed by using electron emission induced by 1.4 keV X-rays. X-ray fluorescence (XRF) analysis has been devoted by using 30 keV electron beam. Scanning electron microscopy (SEM) has been employed to analyze the surface morphology and the X-ray map distribution by using a 30 keV microbeam. Techniques were used to investigate about the patina composition and trace elements as a function of the sample depth obtained coupling XPS to 3 keV argon ion sputtering technique.

  18. Fine Structure of Near-Surface Solar Wind Depth Profile by SNMS/SEM Imaging

    NASA Astrophysics Data System (ADS)

    Baryshev, S. V.; Zinovev, A. V.; Tripa, C. E.; Pellin, M. J.; Burnett, D. S.; Veryovkin, I. V.

    2012-03-01

    In this work, we report results of Genesis Si coupons investigations conducted by laser post-ionization secondary neutral mass spectrometry (LPI SNMS) based on dual beam depth profiling with low energy normal incidence sputtering (lenisDB).

  19. Depth profiling of sol-gel multilayers on fused silica using dynamic SIMS and SNMS

    NASA Astrophysics Data System (ADS)

    Bazin, Nicholas J.; Andrew, James E.; McInnes, Hazel A.; Porter, K. J.; Morris, A. J.

    1999-07-01

    Depth profiling using Dynamic Secondary Ion Mass Spectroscopy through multilayer coatings on fused silica substrates has revealed the effect of increasing the number of layers in the stack. Results are presented for both spin and dip coated multilayers and a significant difference in the interfacial boundary is seen between the two processes. Individual layer thicknesses were estimated using this technique and compared to values gained from UV-Visible spectroscopy. Depth profiling using SNMS of a thick 2-layer system also revealed the thickness of the layers and an indication of the intermixing between them. These measurements agreed well with UV-Vis data. A comparison between these depth-profiling techniques and previous work using AES/XPS depth profiling is discussed.

  20. Corroborative studies of tritium characterization and depth profiles in concrete

    SciTech Connect

    Hochel, R.C.

    2000-05-05

    This report is the second by the authors on characterizing the tritium content of cement and structural concrete. The first report reviewed the literature and used several new methods to characterize tritium on the surface and through the bulk of contaminated concrete at two facilities at the U.S. Department of Energy Savannah River Site (SRS). In both cases, a relatively constant tritium concentration as a function of depth was observed, which has not been previously reported in the literature. These findings were explained as the relatively rapid transport of tritiated liquid through pores of the hydrated cement, and the exchange of tritium with hydrogen found primarily as free and bound water in the hydrated cement binder. The study reported here extended the measurement of surface and bulk tritium in concrete to three other locations at SRS. The purpose of the current study was to characterize locations whose tritium exposure histories were well documented, and to characterize a location exposed exclusively to gaseous tritium, to confirm and possibly extend the knowledge gained from the earlier study. Results of the current study corroborate the earlier findings, in that the tritium concentration was constant through the bulk when exposed to aqueous tritium, even from a single aqueous tritium exposure. Exposure to gaseous tritium, on the other hand, lead to the well-known diffusion controlled variation of tritium concentration reported in the literature. Sufficient exposure history is available to enable a semi-quantitative explanation of the magnitude and depth dependence of the tritium in both the aqueous- and gas-exposed locations. The penetration of tritium from a liquid can be described by a hydraulic flow model, and gaseous tritium permeates in a diffusive manner. The general correlation of properly measured surface tritium activity to that in the underlying bulk found in the earlier study was confirmed. However, the surface and near surface tritium

  1. Spectral analysis of aeromagnetic profiles for depth estimation principles, software, and practical application

    USGS Publications Warehouse

    Sadek, H.S.; Rashad, S.M.; Blank, H.R.

    1984-01-01

    If proper account is taken of the constraints of the method, it is capable of providing depth estimates to within an accuracy of about 10 percent under suitable circumstances. The estimates are unaffected by source magnetization and are relatively insensitive to assumptions as to source shape or distribution. The validity of the method is demonstrated by analyses of synthetic profiles and profiles recorded over Harrat Rahat, Saudi Arabia, and Diyur, Egypt, where source depths have been proved by drilling.

  2. Fine-tuning the etch depth profile via dynamic shielding of ion beam

    NASA Astrophysics Data System (ADS)

    Wu, Lixiang; Qiu, Keqiang; Fu, Shaojun

    2016-08-01

    We introduce a method for finely adjusting the etch depth profile by dynamic shielding in the course of ion beam etching (IBE), which is crucial for the ultra-precision fabrication of large optics. We study the physical process of dynamic shielding and propose a parametric modeling method to quantitatively analyze the shielding effect on etch depths, or rather the shielding rate, where a piecewise Gaussian model is adopted to fit the shielding rate profile. Two experiments were conducted. The experimental result of parametric modeling of shielding rate profiles shows that the shielding rate profile is significantly influenced by the rotary angle of the leaf. The result of the experiment on fine-tuning the etch depth profile shows good agreement with the simulated result, which preliminarily verifies the feasibility of our method.

  3. Breadth and Depth of Vocabulary Knowledge and Their Effects on L2 Vocabulary Profiles

    ERIC Educational Resources Information Center

    Bardakçi, Mehmet

    2016-01-01

    Breadth and depth of vocabulary knowledge have been studied from many different perspectives, but the related literature lacks serious studies dealing with their effects on vocabulary profiles of EFL learners. In this paper, with an aim to fill this gap, the relative effects of breadth and depth of vocabulary knowledge on L2 vocabulary profiles…

  4. Molecular Depth Profiling of Buried Lipid Bilayers Using C60-SIMS

    PubMed Central

    Lu, Caiyan; Wucher, Andreas; Winograd, Nicholas

    2010-01-01

    An organic delta layer system made of alternating Langmuir Blodgett multilayers of barium arachidate (AA) and barium dimyristoyl phosphatidate (DMPA) was constructed to elucidate the factors that control depth resolution in molecular depth profile experiments. More specifically, one or several bilayers of DMPA (4.4 nm) were embedded in relatively thick (51 to 105 nm) multilayer stacks of AA, resulting in a well-defined delta-layer model system closely resembling a biological membrane. 3-D imaging ToF-SIMS depth profile analysis was performed on this system using a focused buckminsterfullerene (C60) cluster ion beam. The delta layer depth response function measured in these experiments exhibits similar features as those determined in inorganic depth profiling, namely an asymmetric shape with quasi-exponential leading and trailing edges and a central Gaussian peak. The effects of sample temperature, primary ion kinetic energy and incident angle on the depth resolution were investigated. While the information depth of the acquired SIMS spectra was found to be temperature independent, the depth resolution was found to be significantly improved at low temperature. Ion induced mixing is proposed to be largely responsible for the broadening, rather than topography, as determined by AFM, therefore depth resolution can be optimized using lower kinetic energy, glancing angle and liquid nitrogen temperature. PMID:21121691

  5. Quantitative depth profiling by laser-ionization sputtered neutral mass spectrometry

    NASA Astrophysics Data System (ADS)

    Higashi, Yasuhiro

    1999-01-01

    Depth profiling by laser-ionization sputtered neutral mass spectrometry (SNMS) is reviewed. The matrix effects, including surface and interface effects, in laser-ionization SNMS and secondary ion mass spectrometry (SIMS) are compared with each other and discussed. Laser-ionization SNMS can provide depth profiles with much smaller matrix effects than conventional SIMS. Depth resolution can effectively be improved by using grazing incidence for the primary ion beam with little interfacial effect. The quantification method in laser-ionization SNMS is also mentioned.

  6. Borehole Paleoclimatology: In search of a minimum depth criterion for terrestrial borehole temperature profiles

    NASA Astrophysics Data System (ADS)

    Beltrami, H.; Smerdon, J. E.; Matharoo, G.; Nickerson, N. R.

    2010-12-01

    One important uncertainty in borehole paleoclimatology that has been overlooked is the degree to which ground surface temperature (GST) reconstructions depend on the maximum depth of the profile. Because the vast majority of measured borehole temperature profiles are acquired from boreholes of opportunity, the maximum measurement depth in data used for paleoclimatic studies varies considerably (beginning at depths as shallow as 100-150 m and extending to depths of more than 1 km). The depth of the borehole is important because the downwelling climatic signal must be separated from the quasi-steady state thermal regime established by the energy in the Earth's interior. This component of the signal is estimated as a linear increase in temperature with depth from the lower section of a borehole temperature profile, which is assumed to be unperturbed by recent changes in climate at the surface. The validity of this assumption is dependent on both the subsurface thermophysical properties and the character of the downwelling climatic signal. Such uncertainties can significantly impact the determination of the quasi-steady state thermal regime, and consequently the magnitude of the temperature anomaly interpreted as a climatic signal. Here we illustrate how the minimum depth of a temperature-depth profile impacts the estimation of the climatic transient and the resultant GST reconstruction. In particular, we attempt to quantitatively illustrate the effects and uncertainties that arise from the analysis of borehole temperature logs of different depths. Our results demonstrate that widely different GST histories can be derived from a single temperature profile truncated at different depths. We show that borehole temperature measurements approaching 500-600 m depths provide the most robust GST reconstructions and are preferable for inferring past climatic variations at the ground surface. Furthermore, we find that the bias introduced by a temperature profile of depths

  7. Investigation of the depth-profiling capabilities of the Storing Matter technique.

    PubMed

    Kasel, B; Wirtz, T

    2015-10-01

    The so-called Storing Matter technique allows the matrix effect observed in secondary ion mass spectrometry to be successfully circumvented. We therefore investigate in this work the depth-profiling capabilities of the Storing Matter technique with a goal of developing protocols for quantitative depth profiles. The effect of the steps involved in the Storing Matter process on the main parameters such as the depth resolution and the dynamic range is studied experimentally and by simulations. A semi-automated process consisting of the sputter-deposition process on a rotating collector in the Storing Matter instrument followed by a complete analysis of the collector by secondary ion mass spectrometry is defined. This protocol is applied to depth profile a B implant in Si and a Sn/Zn multilayered sample, and the results are compared with those obtained with conventional secondary ion mass spectrometry. PMID:26456783

  8. Depth profiling analysis of solar wind helium collected in diamond-like carbon film from Genesis

    DOE PAGESBeta

    Bajo, Ken-ichi; Olinger, Chad T.; Jurewicz, Amy J.G.; Burnett, Donald S.; Sakaguchi, Isao; Suzuki, Taku; Itose, Satoru; Ishihara, Morio; Uchino, Kiichiro; Wieler, Rainer; et al

    2015-10-01

    The distribution of solar-wind ions in Genesis mission collectors, as determined by depth profiling analysis, constrains the physics of ion solid interactions involving the solar wind. Thus, they provide an experimental basis for revealing ancient solar activities represented by solar-wind implants in natural samples. We measured the first depth profile of ⁴He in a collector; the shallow implantation (peaking at <20 nm) required us to use sputtered neutral mass spectrometry with post-photoionization by a strong field. The solar wind He fluence calculated using depth profiling is ~8.5 x 10¹⁴ cm⁻². The shape of the solar wind ⁴He depth profile ismore » consistent with TRIM simulations using the observed ⁴He velocity distribution during the Genesis mission. It is therefore likely that all solar-wind elements heavier than H are completely intact in this Genesis collector and, consequently, the solar particle energy distributions for each element can be calculated from their depth profiles. Ancient solar activities and space weathering of solar system objects could be quantitatively reproduced by solar particle implantation profiles.« less

  9. A comparative study of intervening and associated H I 21-cm absorption profiles in redshifted galaxies

    NASA Astrophysics Data System (ADS)

    Curran, S. J.; Duchesne, S. W.; Divoli, A.; Allison, J. R.

    2016-08-01

    The star-forming reservoir in the distant Universe can be detected through H I 21-cm absorption arising from either cool gas associated with a radio source or from within a galaxy intervening the sight-line to the continuum source. In order to test whether the nature of the absorber can be predicted from the profile shape, we have compiled and analysed all of the known redshifted (z ≥ 0.1) H I 21-cm absorption profiles. Although between individual spectra there is too much variation to assign a typical spectral profile, we confirm that associated absorption profiles are, on average, wider than their intervening counterparts. It is widely hypothesised that this is due to high velocity nuclear gas feeding the central engine, absent in the more quiescent intervening absorbers. Modelling the column density distribution of the mean associated and intervening spectra, we confirm that the additional low optical depth, wide dispersion component, typical of associated absorbers, arises from gas within the inner parsec. With regard to the potential of predicting the absorber type in the absence of optical spectroscopy, we have implemented machine learning techniques to the 55 associated and 43 intervening spectra, with each of the tested models giving a ≳80% accuracy in the prediction of the absorber type. Given the impracticability of follow-up optical spectroscopy of the large number of 21-cm detections expected from the next generation of large radio telescopes, this could provide a powerful new technique with which to determine the nature of the absorbing galaxy.

  10. Aluminum 26, Be-10 and Cl-36 depth profiles in the Canyon Diablo iron meteorite

    NASA Technical Reports Server (NTRS)

    Michlovich, E. S.; Vogt, S.; Masarik, J.; Reedy, R. C.; Elmore, D.; Lipschutz, M. E.

    1994-01-01

    We have measured activities of the long-lived cosmogenic radionuclides Al-26, Be-10, and Cl-36 in 12 fragments of the iron meteorite Canyon Diablo and have constructed production rate-versus-depth profiles of those radionuclides. Profiles determined using differential particle fluxes calculated with the LAHET code system are in good agreement with Al-26, Be-10, and Cl-36 experimental data, but the agreement for Cl-36 was obtained only after neutron-induced cross sections were modified. Profiles calculated with lunar particle fluxes are much lower than experimental Canyon Diablo profiles. The cosmic ray exposure ages of most samples are near 540 m.y.

  11. Assessment of hemoglobin dynamics in traumatic bruises using temperature depth profiling

    NASA Astrophysics Data System (ADS)

    Vidovič, Luka; Milanič, Matija; Majaron, Boris

    2013-11-01

    Perceived color of traumatic bruise depends strongly on depth of the spilled blood, natural skin tone, ambient light conditions, etc., which prevents an accurate and reliable determination of the time of the injury. Pulsed photothermal radiometry (PPTR) allows noninvasive determination of the laser-induced temperature depth profile in human skin. We have applied this technique to characterize dynamics of extravasated hemoglobin in the bruise. Next, we use simple model of mass diffusion and biochemical transformation kinetics to simulate bruise dynamics. By applying Monte Carlo simulation of laser energy deposition, comparison with measured temperature profiles is possible. However, parameters of the model were previously not determined directly. Instead, biologically plausible values were assumed. We show how temperature depth profiling enables accurate monitoring of hemoglobin diffusion and degradation. Parameters of the model, hemoglobin mass diffusivity, hemoglobin degradation time, and skin geometry, can be estimated rather accurately. Derivation of bruise evolution parameters will be a valuable addition to existing bruise age determination techniques.

  12. Objective fitting of hemoglobin dynamics in traumatic bruises based on temperature depth profiling

    NASA Astrophysics Data System (ADS)

    Vidovič, Luka; Milanič, Matija; Majaron, Boris

    2014-02-01

    Pulsed photothermal radiometry (PPTR) allows noninvasive measurement of laser-induced temperature depth profiles. The obtained profiles provide information on depth distribution of absorbing chromophores, such as melanin and hemoglobin. We apply this technique to objectively characterize mass diffusion and decomposition rate of extravasated hemoglobin during the bruise healing process. In present study, we introduce objective fitting of PPTR data obtained over the course of the bruise healing process. By applying Monte Carlo simulation of laser energy deposition and simulation of the corresponding PPTR signal, quantitative analysis of underlying bruise healing processes is possible. Introduction of objective fitting enables an objective comparison between the simulated and experimental PPTR signals. In this manner, we avoid reconstruction of laser-induced depth profiles and thus inherent loss of information in the process. This approach enables us to determine the value of hemoglobin mass diffusivity, which is controversial in existing literature. Such information will be a valuable addition to existing bruise age determination techniques.

  13. Quantitative operando visualization of the energy band depth profile in solar cells.

    PubMed

    Chen, Qi; Mao, Lin; Li, Yaowen; Kong, Tao; Wu, Na; Ma, Changqi; Bai, Sai; Jin, Yizheng; Wu, Dan; Lu, Wei; Wang, Bing; Chen, Liwei

    2015-01-01

    The energy band alignment in solar cell devices is critically important because it largely governs elementary photovoltaic processes, such as the generation, separation, transport, recombination and collection of charge carriers. Despite the expenditure of considerable effort, the measurement of energy band depth profiles across multiple layers has been extremely challenging, especially for operando devices. Here we present direct visualization of the surface potential depth profile over the cross-sections of operando organic photovoltaic devices using scanning Kelvin probe microscopy. The convolution effect due to finite tip size and cantilever beam crosstalk has previously prohibited quantitative interpretation of scanning Kelvin probe microscopy-measured surface potential depth profiles. We develop a bias voltage-compensation method to address this critical problem and obtain quantitatively accurate measurements of the open-circuit voltage, built-in potential and electrode potential difference. PMID:26166580

  14. Laser-induced plasma spectroscopy depth profile analysis: a contribution to authentication

    NASA Astrophysics Data System (ADS)

    Agresti, J.; Osticioli, I.; Mencaglia, A. A.; Siano, S.

    2013-05-01

    Here the exploitation of the laser induced plasma spectroscopy (LIPS) depth profiling in authentication studies of copper alloy and earthenware artifacts was investigated. Such an approach to the discrimination between original and counterfeit objects is based on the examination of the amplitude and shape of elemental distributions along ablation depths of several hundred microns. Thus, its application pass through preliminary assessments and correction of possible systematic errors of the measured profiles, which was the main aim of the present work. LIPS and ESEM-EDX measurements were carried out on two archaeological findings. We show that deep analytical probing produces not negligible intrinsic broadenings of the measured elemental Sn and Ca peaks and propose a correction based on the convolution integral. According to the latter, we demonstrate the actual depth profile can be calculated from the measured one through the experimental determination of the step response and the application of trial-and-error method.

  15. Quantitative operando visualization of the energy band depth profile in solar cells

    PubMed Central

    Chen, Qi; Mao, Lin; Li, Yaowen; Kong, Tao; Wu, Na; Ma, Changqi; Bai, Sai; Jin, Yizheng; Wu, Dan; Lu, Wei; Wang, Bing; Chen, Liwei

    2015-01-01

    The energy band alignment in solar cell devices is critically important because it largely governs elementary photovoltaic processes, such as the generation, separation, transport, recombination and collection of charge carriers. Despite the expenditure of considerable effort, the measurement of energy band depth profiles across multiple layers has been extremely challenging, especially for operando devices. Here we present direct visualization of the surface potential depth profile over the cross-sections of operando organic photovoltaic devices using scanning Kelvin probe microscopy. The convolution effect due to finite tip size and cantilever beam crosstalk has previously prohibited quantitative interpretation of scanning Kelvin probe microscopy-measured surface potential depth profiles. We develop a bias voltage-compensation method to address this critical problem and obtain quantitatively accurate measurements of the open-circuit voltage, built-in potential and electrode potential difference. PMID:26166580

  16. Quantitative operando visualization of the energy band depth profile in solar cells

    NASA Astrophysics Data System (ADS)

    Chen, Qi; Mao, Lin; Li, Yaowen; Kong, Tao; Wu, Na; Ma, Changqi; Bai, Sai; Jin, Yizheng; Wu, Dan; Lu, Wei; Wang, Bing; Chen, Liwei

    2015-07-01

    The energy band alignment in solar cell devices is critically important because it largely governs elementary photovoltaic processes, such as the generation, separation, transport, recombination and collection of charge carriers. Despite the expenditure of considerable effort, the measurement of energy band depth profiles across multiple layers has been extremely challenging, especially for operando devices. Here we present direct visualization of the surface potential depth profile over the cross-sections of operando organic photovoltaic devices using scanning Kelvin probe microscopy. The convolution effect due to finite tip size and cantilever beam crosstalk has previously prohibited quantitative interpretation of scanning Kelvin probe microscopy-measured surface potential depth profiles. We develop a bias voltage-compensation method to address this critical problem and obtain quantitatively accurate measurements of the open-circuit voltage, built-in potential and electrode potential difference.

  17. A simple method of obtaining concentration depth-profiles from X-ray diffraction

    NASA Technical Reports Server (NTRS)

    Wiedemann, K. E.; Unnam, J.

    1984-01-01

    The construction of composition profiles from X-ray intensity bands was investigated. The intensity band-to-composition profile transformation utilizes a solution which can be easily evaluated. The technique can be applied to thin films and thick speciments for which the variation of lattice parameters, linear absorption coefficient, and reflectivity with composition are known. A deconvolution scheme with corrections for the instrumental broadening and ak-alfadoublet is discussed.

  18. Simulations of the Aerosol Index and the Absorption Aerosol Optical Depth and Comparisons with OMI Retrievals During ARCTAS-2008 Campaign

    NASA Technical Reports Server (NTRS)

    2010-01-01

    We have computed the Aerosol Index (AI) at 354 nm, useful for observing the presence of absorbing aerosols in the atmosphere, from aerosol simulations conducted with the Goddard Chemistry, Aerosol, Radiation, and Transport (GOCART) module running online the GEOS-5 Atmospheric GCM. The model simulates five aerosol types: dust, sea salt, black carbon, organic carbon and sulfate aerosol and can be run in replay or data assimilation modes. In the assimilation mode, information's provided by the space-based MODIS and MISR sensors constrains the model aerosol state. Aerosol optical properties are then derived from the simulated mass concentration and the Al is determined at the OMI footprint using the radiative transfer code VLIDORT. In parallel, model derived Absorption Aerosol Optical Depth (AAOD) is compared with OMI retrievals. We have focused our study during ARCTAS (June - July 2008), a period with a good sampling of dust and biomass burning events. Our ultimate goal is to use OMI measurements as independent validation for our MODIS/MISR assimilation. Towards this goal we document the limitation of OMI aerosol absorption measurements on a global scale, in particular sensitivity to aerosol vertical profile and cloud contamination effects, deriving the appropriate averaging kernels. More specifically, model simulated (full) column integrated AAOD is compared with model derived Al, this way identifying those regions and conditions under which OMI cannot detect absorbing aerosols. Making use of ATrain cloud measurements from MODIS, C1oudSat and CALIPSO we also investigate the global impact on clouds on OMI derived Al, and the extent to which GEOS-5 clouds can offer a first order representation of these effects.

  19. ToF-SIMS Depth Profiling Of Insulating Samples, Interlaced Mode Or Non-interlaced Mode?

    SciTech Connect

    Wang, Zhaoying; Jin, Ke; Zhang, Yanwen; Wang, Fuyi; Zhu, Zihua

    2014-11-01

    Dual beam depth profiling strategy has been widely adopted in ToF-SIMS depth profiling, in which two basic operation modes, interlaced mode and non-interlaced mode, are commonly used. Generally, interlaced mode is recommended for conductive or semi-conductive samples, whereas non-interlaced mode is recommended for insulating samples, where charge compensation can be an issue. Recent publications, however, show that the interlaced mode can be used effectively for glass depth profiling, despite the fact that glass is an insulator. In this study, we provide a simple guide for choosing between interlaced mode and non-interlaced mode for insulator depth profiling. Two representative cases are presented: (1) depth profiling of a leached glass sample, and (2) depth profiling of a single crystal MgO sample. In brief, the interlaced mode should be attempted first, because (1) it may provide reasonable-quality data, and (2) it is time-saving for most cases, and (3) it introduces low H/C/O background. If data quality is the top priority and measurement time is flexible, non-interlaced mode is recommended because interlaced mode may suffer from low signal intensity and poor mass resolution. A big challenge is tracking trace H/C/O in a highly insulating sample (e.g., MgO), because non-interlaced mode may introduce strong H/C/O background but interlaced mode may suffer from low signal intensity. Meanwhile, a C or Au coating is found to be very effective to improve the signal intensity. Surprisingly, the best analyzing location is not on the C or Au coating, but at the edge (outside) of the coating.

  20. High resolution TOF - SIMS depth profiling of nano-film multilayers

    SciTech Connect

    Bhushan, K. G.; Mukundhan, R.; Gupta, S. K.

    2013-02-05

    We present the results of depth profiling studies conducted using an indigenously developed dual-beam high resolution Time-of-Flight Secondary Ion Mass Spectrometer (TOF-SIMS) on thinfilm W-C-W multilayer structure grown on Si substrate. Opto 8 layers could be clearly identified. Mixing of layers is seen which from analysis using roughness model calculations indicate a mixing thickness of about 2nm that correspond to the escape depth of secondary ions from the sample.

  1. Contribution of a visual pigment absorption spectrum to a visual function: depth perception in a jumping spider

    PubMed Central

    Nagata, Takashi; Arikawa, Kentaro; Terakita, Akihisa

    2013-01-01

    Absorption spectra of visual pigments are adaptively tuned to optimize informational capacity in most visual systems. Our recent investigation of the eyes of the jumping spider reveals an apparent exception: the absorption characteristics of a visual pigment cause defocusing of the image, reducing visual acuity generally in a part of the retina. However, the amount of defocus can theoretically provide a quantitative indication of the distance of an object. Therefore, we proposed a novel mechanism for depth perception in jumping spiders based on image defocus. Behavioral experiments revealed that the depth perception of the spider depended on the wavelength of the ambient light, which affects the amount of defocus because of chromatic aberration of the lens. This wavelength effect on depth perception was in close agreement with theoretical predictions based on our hypothesis. These data strongly support the hypothesis that the depth perception mechanism of jumping spiders is based on image defocus.

  2. Erosion Rate Variations during XPS Sputter Depth Profiling of Nanoporous Films

    SciTech Connect

    Gaspar, Dan J.; Engelhard, Mark H.; Henry, Matthew C.; Baer, Donald R.

    2005-04-01

    Sputter depth profiling is commonly used to obtain valuable information regarding the three dimensional distribution of elements within a sample, and is one of the best ways to measure the composition of a buried interface or the uniformity of a thin film. X-ray photoelectron spectroscopy (XPS) is one of the analysis tools often used in conjunction with ion beam erosion to obtain sputter depth profiles. However, to obtain accurate depth information it is often necessary to better understand the sputtering process for a specific materials system. Artifacts such as differential sputtering, varying sputter rates and ion beam-induced chemistry are well known. Here, however, we present evidence from experiments on a porous thin film deposited on a Si wafer that relatively small chemical and/or structural changes in a nanoporous film can affect the rate of erosion measured during sputter depth profiling. Reproducible variations in sputter rate are found with chemical modification leading to compositional changes of the nanoporous thin film. The origin of the sputter rate changes is discussed with the aid of results obtained using Fourier transform infrared spectroscopy, profilometry, nuclear reaction analysis, electron microscopy and XPS-based depth profiling.

  3. Fundamental studies of molecular depth profiling using organic delta layers as model systems

    PubMed Central

    Lu, C.; Wucher, A.; Winograd, N.

    2012-01-01

    Alternating Langmuir–Blodgett multilayers of barium arachidate (AA) and barium dimyristoyl phosphatidate (DMPA) were used to elucidate the factors that control depth resolution in molecular depth profiling experiments. More specifically, thin (4.4 nm) layers of DMPA were embedded in relatively thick (~50 nm) multilayer stacks of AA, resulting in a well-defined delta-layer model system closely resembling a biological membrane. This system was subjected to a three-dimensional imaging depth profile analysis using a focused buckminsterfullerene (C60) cluster ion beam. The depth response function measured in these experiments exhibits similar features as those determined in inorganic depth profiling: namely, an asymmetric shape with quasi-exponential leading and trailing edges and a central Gaussian peak. The magnitude of the corresponding characteristic rise and decay lengths is found to be 5 and 16 nm, respectively, while the total half width of the response function characterizing the apparent depth resolution was about 29 nm. Ion-induced mixing is proposed to be largely responsible for the broadening, rather than topography, as determined by atomic force microscopy. PMID:24347743

  4. Quantification problems in depth profiling of pwr steels using Ar+ ion sputtering and XPS analysis.

    PubMed

    Ignatova, Velislava A; Van Den Berghe, Sven; Van Dyck, Steven; Popok, Vladimir N

    2006-10-01

    The oxide scales of AISI 304 formed in boric acid solutions at 300 degrees C and pH = 4.5 have been studied using X-ray photoelectron spectroscopy (XPS) depth profiling. The present focus is depth profile quantification both in depth and chemical composition on a molecular level. The roughness of the samples is studied by atomic force microscopy before and after sputtering, and the erosion rate is determined by measuring the crater depth with a surface profilometer and vertical scanning interferometry. The resulting roughness (20-30 nm), being an order of magnitude lower than the crater depth (0.2-0.5 microm), allows layer-by-layer profiling, although the ion-induced effects result in an uncertainty of the depth calibration of a factor of 2. The XPS spectrum deconvolution and data evaluation applying target factor analysis allows chemical speciation on a molecular level. The elemental distribution as a function of the sputtering time is obtained, and the formation of two layers is observed-one hydroxide (mainly iron-nickel based) on top and a second one deeper, mainly consisting of iron-chromium oxides. PMID:16984670

  5. Cluster secondary ion mass spectrometry and the temperature dependence of molecular depth profiles.

    PubMed

    Mao, Dan; Wucher, Andreas; Brenes, Daniel A; Lu, Caiyan; Winograd, Nicholas

    2012-05-01

    The quality of molecular depth profiles created by erosion of organic materials by cluster ion beams exhibits a strong dependence upon temperature. To elucidate the fundamental nature of this dependence, we employ the Irganox 3114/1010 organic delta-layer reference material as a model system. This delta-layer system is interrogated using a 40 keV C(60)(+) primary ion beam. Parameters associated with the depth profile such as depth resolution, uniformity of sputtering yield, and topography are evaluated between 90 and 300 K using a unique wedge-crater beveling strategy that allows these parameters to be determined as a function of erosion depth from atomic force microscope (AFM) measurements. The results show that the erosion rate calibration performed using the known Δ-layer depth in connection with the fluence needed to reach the peak of the corresponding secondary ion mass spectrometry (SIMS) signal response is misleading. Moreover, we show that the degradation of depth resolution is linked to a decrease of the average erosion rate and the buildup of surface topography in a thermally activated manner. This underlying process starts to influence the depth profile above a threshold temperature between 210 and 250 K for the system studied here. Below that threshold, the process is inhibited and steady-state conditions are reached with constant erosion rate, depth resolution, and molecular secondary ion signals from both the matrix and the Δ-layers. In particular, the results indicate that further reduction of the temperature below 90 K does not lead to further improvement of the depth profile. Above the threshold, the process becomes stronger at higher temperature, leading to an immediate decrease of the molecular secondary ion signals. This signal decay is most pronounced for the highest m/z ions but is less for the smaller m/z ions, indicating a shift toward small fragments by accumulation of chemical damage. The erosion rate decay and surface roughness buildup

  6. Thermal Depth Profiling Reconstruction by Multilayer Thermal Quadrupole Modeling and Particle Swarm Optimization

    NASA Astrophysics Data System (ADS)

    Chen, Zhao-Jiang; Zhang, Shu-Yi

    2010-02-01

    A new hybrid inversion method for depth profiling reconstruction of thermal conductivities of inhomogeneous solids is proposed based on multilayer quadrupole formalism of thermal waves, particle swarm optimization and sequential quadratic programming. The reconstruction simulations for several thermal conductivity profiles are performed to evaluate the applicability of the method. The numerical simulations demonstrate that the precision and insensitivity to noise of the inversion method are very satisfactory.

  7. 10Be depth-profile dating of glaciofluvial sediments in the northern Alpine Foreland

    NASA Astrophysics Data System (ADS)

    Claude, Anne; Akçar, Naki; Ivy-Ochs, Susan; Schlunegger, Fritz; Kubik, Peter; Christl, Marcus; Vockenhuber, Christof; Dehnert, Andreas; Rahn, Meinert; Schlüchter, Christian

    2016-04-01

    10Be depth-profile dating is based on the fact that nuclide production is decreasing as an exponential function of depth. This method requires collecting at least four sediment samples in a vertical profile. The obtained nuclide concentrations are plotted against depth and fitted depth-profiles to the measured dataset. The age is then calculated based on the best-fit. The requirements for this method are the following: sampling geological units in artificial outcrops with minimum thickness of soil (less than around 80 cm), preferably with a flat-topped landform in order to guarantee that the uppermost surface of the deposit remains as unmodified as possible and is related to a defined geomorphologic process. Additionally at least one sample, preferably three, from the uppermost one meter of the profile as the exponential decrease mainly occurs around this depth. No sample is collected from the overlying soil. In this study, we aim to establish the chronology of the oldest Quaternary sediments in the northern Alpine Foreland using depth-profile dating with 10Be. These ages contribute to the understanding of the Quaternary landscape evolution of the Alpine Foreland. Here, we unravel the chronology of five sites at different morphostratigraphic positions: Mandach and Ängi (canton Aargau), Stadlerberg and Irchel (canton Zurich) and Rechberg (Germany, 4 km from the border to Switzerland). All sites are abandoned gravel pits and at each site we collected between four and seven sediment samples. First results yielded chronologies between 0.8 and 2 Ma for these glaciofluvial deposits. Our study shows that this relatively new method is successful when the geological setting matches the methodological requirements.

  8. 10Be depth profile dating in the Swiss Midlands: deposition ages versus erosion

    NASA Astrophysics Data System (ADS)

    Wüthrich, Lorenz; Zech, Roland; Haghipour, Negar; Terrizzano, Carla; Christl, Marcus; Gnägi, Christian; Veit, Heinz; Ivy-Ochs, Susan

    2015-04-01

    During the Pleistocene, glaciers advanced repeatedly from the Alps into the Swiss Midlands. The exact extents and timing are still under debate, even for the last glacial advances. Decalcification depths, for example, increase from west to east in the western Swiss Midlands and have been interpreted to indicate that the Rhone glacier may have been less extensive during the global Last Glacial Maximum (LGM) at 20 ka than assumed so far [1]. In an attempt to provide more quantitative age control, we applied 10Be depth profile dating [2] on till at five locations in the western part of Switzerland. Two of them lie outside the assumed LGM extent of the Rhone glacier (Niederbuchsiten, St.Urban), two inside the extent of the LGM Rhone glacier (Steinhof, Deisswil) and one profile was taken from the Berne stade (LGM) of the Aare glacier [3]. All surface concentrations are relatively low and indicate massive erosion. Without constrains for age and erosion, depth profile dating yields ages between roughly 15 ka up to more than 1 Ma for the profiles in St. Urban, Niederbuchsiten and Deisswil whereas the profiles in Steinhof and Bern yields only last glacial ages. The wide range of possible exposure ages illustrates, that independent estimates for erosion would be needed to precisely determine the deposition ages of the investigated tills. However, at this point, we interpret the best model fits to our depth profile concentrations as tentative verification of the assumed LGM extent [3]. The spatial patterns of decalcification depths and soil development in the Swiss Midlands deserves further evaluation. [1] Bitterli et al. (2011) Geologischer Atlas der Schweiz, Blatt 1108, Swisstopo [2] Hidy et al. (2010) Geochem. Geophys. Geosyst. 11, doi:10.1029/2010GC003084 . [3] Bini et al. (2009) Switzerland during the Last Glacial Maximum, Swisstopo

  9. Case study of absorption aerosol optical depth closure of black carbon over the East China Sea

    NASA Astrophysics Data System (ADS)

    Koike, M.; Moteki, N.; Khatri, P.; Takamura, T.; Takegawa, N.; Kondo, Y.; Hashioka, H.; Matsui, H.; Shimizu, A.; Sugimoto, N.

    2014-01-01

    aerosol optical depth (AAOD) measurements made by sun-sky photometers are currently the only constraint available for estimates of the global radiative forcing of black carbon (BC), but their validation studies are limited. In this paper, we report the first attempt to compare AAODs derived from single-particle soot photometer (SP2) and ground-based sun-sky photometer (sky radiometer, SKYNET) measurements. During the Aerosol Radiative Forcing in East Asia (A-FORCE) experiments, BC size distribution and mixing state vertical profiles were measured using an SP2 on board a research aircraft near the Fukue Observatory (32.8°N, 128.7°E) over the East China Sea in spring 2009 and late winter 2013. The aerosol extinction coefficients (bext) and single scattering albedo (SSA) at 500 nm were calculated based on aerosol size distribution and detailed BC mixing state information. The calculated aerosol optical depth (AOD) agreed well with the sky radiometer measurements (2 ± 6%) when dust loadings were low (lidar-derived nonspherical particle contribution to AOD less than 20%). However, under these low-dust conditions, the AAODs obtained from sky radiometer measurements were only half of the in situ estimates. When dust loadings were high, the sky radiometer measurements showed systematically higher AAODs even when all coarse particles were assumed to be dust for in situ measurements. These results indicate that there are considerable uncertainties in AAOD measurements. Uncertainties in the BC refractive index, optical calculations from in situ data, and sky radiometer retrieval analyses are discussed.

  10. Depth profiling in amorphous and microcrystalline silicon by transient photoconductivity techniques

    NASA Astrophysics Data System (ADS)

    Brüggemann, R.; Main, C.; Reynolds, S.

    2002-07-01

    We probe near-surface regions in hydrogenated amorphous and microcrystalline silicon by recording the transient photocurrent after application of a green laser pulse with short absorption depth through the glass-substrate/silicon interface. Depending on the spatial defect inhomogeneity close to the illuminated surface the transient photocurrent shows a different decay behaviour under strongly absorbed green light as compared with more uniformly absorbed red illumination. We apply a Fourier transform technique to the photocurrent decay, which reveals spatial inhomogeneities in the deep-defect density in amorphous silicon. For a highly crystalline sample of microcrystalline silicon we find depth homogeneity in the electronic properties, in agreement with information from structural investigations.

  11. Estimation of skin concentrations of topically applied lidocaine at each depth profile.

    PubMed

    Oshizaka, Takeshi; Kikuchi, Keisuke; Kadhum, Wesam R; Todo, Hiroaki; Hatanaka, Tomomi; Wierzba, Konstanty; Sugibayashi, Kenji

    2014-11-20

    Skin concentrations of topically administered compounds need to be considered in order to evaluate their efficacies and toxicities. This study investigated the relationship between the skin permeation and concentrations of compounds, and also predicted the skin concentrations of these compounds using their permeation parameters. Full-thickness skin or stripped skin from pig ears was set on a vertical-type diffusion cell, and lidocaine (LID) solution was applied to the stratum corneum (SC) in order to determine in vitro skin permeability. Permeation parameters were obtained based on Fick's second law of diffusion. LID concentrations at each depth of the SC were measured using tape-stripping. Concentration-depth profiles were obtained from viable epidermis and dermis (VED) by analyzing horizontal sections. The corresponding skin concentration at each depth was calculated based on Fick's law using permeation parameters and then compared with the observed value. The steady state LID concentrations decreased linearly as the site became deeper in SC or VED. The calculated concentration-depth profiles of the SC and VED were almost identical to the observed profiles. The compound concentration at each depth could be easily predicted in the skin using diffusion equations and skin permeation data. Thus, this method was considered to be useful for promoting the efficient preparation of topically applied drugs and cosmetics. PMID:25158219

  12. The Non-Linear Relationship between Silicate Absorption Depth and IR Extinction in Dense Clouds

    NASA Astrophysics Data System (ADS)

    Chiar, Jean E.; Pendleton, Y.; Ennico, K.; Boogert, A.; Greene, T.; Lada, C.; Roellig, T.; Tielens, A.; Werner, M.; Whittet, D.

    2006-12-01

    Interstellar silicates are likely to be a part of all grains responsible for extinction in the diffuse interstellar medium (ISM) and dense clouds. A correlation between visual extinction (Av) and the depth of the 9.7 mu silicate feature (measured as optical depth, tau(9.7)) is expected if the dust species are well mixed. In the diffuse ISM, such a correlation is observed for lines of sight in the solar neighborhood. A previous study of the silicate absorption feature in the Taurus dark cloud showed a tendency for the correlation to break down at high Av (Whittet et al. 1988, MNRAS, 233, 321), but the scatter was large. We have acquired Spitzer Infrared Spectrograph data of several lines of sight in the IC 5146, Barnard 68, Chameleon I and Serpens dense clouds. To eliminate any uncertainties associated with adopting a specific extinction law, we investigated the relationship between tau(9.7) and E(J-K). Our data set spans E(J-K) between 0.3 and 8 mag (Av=between 2-35 mag.). All lines of sight show the 9.7 mu silicate feature. For E(J-K) greater than about 2 mag, tau(9.7) levels off, much like the trend observed in the Taurus data. There are two exceptions: one line of sight in Serpens, with E(J-K) 4 mag lies on the diffuse ISM line. Another line of sight with E(J-K) 8 mag, also in Serpens, lies well below the diffuse ISM line, but well above the “flat” trend of the other dense cloud sources. This particular line of sight also has a high ice column relative to the amount of visual/infrared extinction. The cause of the “flat” trend exhibited by most of the dense cloud points is undetermined. However, in general, it is unlikely that ice mantles would have any effect on the measured silicate feature since ices are transparent in the 10 mu region.

  13. Nondestructive elemental depth-profiling analysis by muonic X-ray measurement.

    PubMed

    Ninomiya, Kazuhiko; Kubo, Michael K; Nagatomo, Takashi; Higemoto, Wataru; Ito, Takashi U; Kawamura, Naritoshi; Strasser, Patrick; Shimomura, Koichiro; Miyake, Yasuhiro; Suzuki, Takao; Kobayashi, Yoshio; Sakamoto, Shinichi; Shinohara, Atsushi; Saito, Tsutomu

    2015-05-01

    Elemental analysis of materials is fundamentally important to science and technology. Many elemental analysis methods have been developed, but three-dimensional nondestructive elemental analysis of bulk materials has remained elusive. Recently, our project team, dreamX (damageless and regioselective elemental analysis with muonic X-rays), developed a nondestructive depth-profiling elemental analysis method after a decade of research. This new method utilizes a new type of probe; a negative muon particle and high-energy muonic X-rays emitted after the muon stops in a material. We performed elemental depth profiling on an old Japanese gold coin (Tempo-Koban) using a low-momentum negative muon beam and successfully determined that the Au concentration in the coin gradually decreased with depth over a micrometer length scale. We believe that this method will be a promising tool for the elemental analysis of valuable samples, such as archeological artifacts. PMID:25901421

  14. Determination of aerosol extinction coefficient profiles from LIDAR data using the optical depth solution method

    NASA Astrophysics Data System (ADS)

    Aparna, John; Satheesh, S. K.; Mahadevan Pillai, V. P.

    2006-12-01

    The LIDAR equation contains four unknown variables in a two-component atmosphere where the effects caused by both molecules and aerosols have to be considered. The inversion of LIDAR returns to retrieve aerosol extinction profiles, thus, calls for some functional relationship to be assumed between these two. The Klett's method, assumes a functional relationship between the extinction and backscatter. In this paper, we apply a different technique, called the optical depth solution, where we made use of the total optical depth or transmittance of the atmosphere along the LIDAR-measurement range. This method provides a stable solution to the LIDAR equation. In this study, we apply this technique to the data obtained using a micro pulse LIDAR (MPL, model 1000, Science and Engineering Services Inc) to retrieve the vertical distribution of aerosol extinction coefficient. The LIDAR is equipped with Nd-YLF laser at an operating wavelength of 523.5 nm and the data were collected over Bangalore. The LIDAR data are analyzed to get to weighted extinction coefficient profiles or the weighted sum of aerosol and molecular extinction coefficient profiles. Simultaneous measurements of aerosol column optical depth (at 500 nm) using a Microtops sun photometer were used in the retrievals. The molecular extinction coefficient is determined assuming standard atmospheric conditions. The aerosol extinction coefficient profiles are determined by subtracting the molecular part from the weighted extinction coefficient profiles. The details of the method and the results obtained are presented.

  15. Characterization of penetration depth as a function of optical fiber separation at various absorption and scatter coefficients for a noninvasive metabolic sensor

    NASA Astrophysics Data System (ADS)

    DeMilo, Charles; Brukilacchio, Thomas; Soller, Babs R.; Soyemi, Olusola

    2004-06-01

    A visible-near IR (500-1,000nm) fiber optic sensor is under development that is intended to non-invasively assess muscle metabolism through the measurement of tissue pH and oxygen partial pressure. These parameters are calculated from the spectra of hemoglobin and myoglobin in muscle. The sensor consists of transmit (illumination) fibers and receive (detection) fibers that are coupled to a spectrometer. Light from the probe must penetrate below the surface of the skin and into a 5-10mm thick layer of muscle. A study was conducted to quantify the relationship between transmit and receive fiber separation and sensor penetration depth below the surface of the skin. A liquid phantom was created to replicate the absorption (μa) and reduced scatter coefficient (μs') profiles typically found in human blood and tissue. The phantom consisted of a solution of Intralipid and India ink in the appropriate concentrations to achieve desired reduced scatter coefficient and absorption profiles. The reduced scatter coefficient of the liquid phantom was achieved to an accuracy of +/-10% compared to previously published data. A fixed illumination fiber and translatable detector fiber were placed in the liquid phantom, and the fiber separation was varied from 3-40mm. Values of μa and μs' varied from 0.03-0.40 cm-1 and 5.0-15.0 cm-1 respectively. Results from the experiment demonstrate a strong correlation between penetration depth and fiber separation. Additionally, it was found that penetration depth was not substantially influenced by absorption and scatter concentration. As signal-to-noise is an important parameter in many non-invasive biomedical applications, the relative signal as a function of fiber separation was determined to follow an exponential relationship.

  16. Determining concentration depth profiles in fluorinated networks by means of electric force microscopy

    SciTech Connect

    Miccio, Luis A.; Schwartz, Gustavo A.

    2011-08-14

    By means of electric force microscopy, composition depth profiles were measured with nanometric resolution for a series of fluorinated networks. By mapping the dielectric permittivity along a line going from the surface to the bulk, we were able to experimentally access to the fluorine concentration profile. Obtained data show composition gradient lengths ranging from 30 nm to 80 nm in the near surface area for samples containing from 0.5 to 5 wt. % F, respectively. In contrast, no gradients of concentration were detected in bulk. This method has several advantages over other techniques because it allows profiling directly on a sectional cut of the sample. By combining the obtained results with x-ray photoelectron spectroscopy measurements, we were also able to quantify F/C ratio as a function of depth with nanoscale resolution.

  17. Oxygen fugacity profile of the oceanic upper mantle and the depth of redox melting beneath ridges

    NASA Astrophysics Data System (ADS)

    Davis, F. A.; Cottrell, E.

    2014-12-01

    Oxygen fugacity (fO2) of a mantle mineral assemblage, controlled primarily by Fe redox chemistry, sets the depth of the diamond to carbonated melt reaction (DCO3). Near-surface fO2 recorded by primitive MORB glasses and abyssal peridotites anchor the fO2 profile of the mantle at depth. If the fO2-depth relationship of the mantle is known, then the depth of the DCO3 can be predicted. Alternatively, if the DCO3 can be detected geophysically, then its depth can be used to infer physical and chemical characteristics of upwelling mantle. We present an expanded version of a model of the fO2-depth profile of adiabatically upwelling mantle first presented by Stagno et al. (2013), kindly provided by D. Frost. The model uses a chemical mass balance and empirical fits to experimental data to calculate compositions and modes of mantle minerals at specified P, T, and bulk Fe3+/ƩFe. We added P and T dependences to the partitioning of Al and Ca to better simulate the mineralogical changes in peridotite at depth and included majorite component in garnet to increase the depth range of the model. We calculate fO2 from the mineral assemblages using the grt-ol-opx oxybarometer (Stagno et al., 2013). The onset of carbonated melting occurs at the intersection of a Fe3+/ƩFe isopleth with the DCO3. Upwelling mantle is tied to the DCO3 until all native C is oxidized to form carbonated melts by reduction of Fe3+ to Fe2+. The depth of intersection of a parcel of mantle with the DCO3 is a function of bulk Fe3+/ƩFe, potential temperature, and bulk composition. We predict that fertile mantle (PUM) along a 1400 °C adiabat, with 50 ppm bulk C, and Fe3+/ƩFe = 0.05 after C oxidation begins redox melting at a depth of 250 km. The model contextualizes observations of MORB redox chemistry. Because fertile peridotite is richer in Al2O3, the Fe2O3-bearing components of garnet are diluted leading to lower fO2 at a given depth compared to refractory mantle under the same conditions. This may indicate

  18. AMS method for depth profiling of trace elements concentration in materials - Construction and applications

    NASA Astrophysics Data System (ADS)

    Stan-Sion, C.; Enachescu, M.

    2015-10-01

    The need to investigate the behavior of solid state materials on the impact/retention/repulsion/contamination/impregnation with special trace elements or radioactive elements has driven us to develop a modified Accelerator Mass Spectrometry (AMS) analyzing method that is able to perform the measurement of the concentration depth profile of an element in a host material. This upgraded method that we call AMS-depth profiling method (AMS-DP) measures continuously the concentration of a trace element in a given sample material as a function of the depth from the surface (e.g., tritium in carbon, deuterium in tungsten, etc.). However, in order to perform depth profiling, common AMS facilities have to undergo several changes: a new replaceable sample target-holder has to be constructed to accept small plates of solid material as samples; their position has to be adjusted in the focus point of the sputter beam; crater rim effects of the produced hole in the sample have to be avoided or removed from the registered events in the detector; suitable reference samples have to be prepared and used for calibration. All procedures are presented in the paper together with several applications.

  19. Reconstructing accurate ToF-SIMS depth profiles for organic materials with differential sputter rates.

    PubMed

    Taylor, Adam J; Graham, Daniel J; Castner, David G

    2015-09-01

    To properly process and reconstruct 3D ToF-SIMS data from systems such as multi-component polymers, drug delivery scaffolds, cells and tissues, it is important to understand the sputtering behavior of the sample. Modern cluster sources enable efficient and stable sputtering of many organics materials. However, not all materials sputter at the same rate and few studies have explored how different sputter rates may distort reconstructed depth profiles of multicomponent materials. In this study spun-cast bilayer polymer films of polystyrene and PMMA are used as model systems to optimize methods for the reconstruction of depth profiles in systems exhibiting different sputter rates between components. Transforming the bilayer depth profile from sputter time to depth using a single sputter rate fails to account for sputter rate variations during the profile. This leads to inaccurate apparent layer thicknesses and interfacial positions, as well as the appearance of continued sputtering into the substrate. Applying measured single component sputter rates to the bilayer films with a step change in sputter rate at the interfaces yields more accurate film thickness and interface positions. The transformation can be further improved by applying a linear sputter rate transition across the interface, thus modeling the sputter rate changes seen in polymer blends. This more closely reflects the expected sputtering behavior. This study highlights the need for both accurate evaluation of component sputter rates and the careful conversion of sputter time to depth, if accurate 3D reconstructions of complex multi-component organic and biological samples are to be achieved. The effects of errors in sputter rate determination are also explored. PMID:26185799

  20. Hydrogen depth profiling with sub-nm resolution in high-resolution ERD

    NASA Astrophysics Data System (ADS)

    Kimura, Kenji; Nakajima, Kaoru; Imura, Hideki

    1998-05-01

    A depth resolution of 0.28 nm is obtained in a depth profile of hydrogen in silicon using a newly developed high-resolution elastic recoil detection (ERD) system. The system consists of a standard 90° sector magnetic spectrometer (energy resolution ˜0.1%) for high-resolution measurement and an electrostatic deflector for blocking scattered incident ions without disturbing the energy resolution. The system is very simple as compared with other high-resolution ERD systems and the data acquisition time is reasonably short.

  1. Oxygen bleed-in during SIMS depth profiling: curse or blessing?

    NASA Astrophysics Data System (ADS)

    Zalm, P. C.; Vriezema, C. J.

    1992-02-01

    Oxygen flooding of the target during SIMS depth profiling finds widespread application foranumber of reasons. Among others it enhances the (positive) secondary ionization efficiency, helps in suppressing bombardment-induced surface topography development and reduces the transition time to steady-state erosion conditions. These attractive properties are offset by a number of artefacts that may be introduced by O 2 inlet. A summary of vices and virtues, largely based on existing knowledge, is presented. Then one of the few open questions is addressed, namely to what extent O 2 bleed-in ffects depth resolution. This is examined in some detail by studying ultrashallow dopant profiles of B, P, Ga or Sb in Si by SIMS with and without O 2 leak.

  2. Depth profiling and imaging capabilities of an ultrashort pulse laser ablation time of flight mass spectrometer

    PubMed Central

    Cui, Yang; Moore, Jerry F.; Milasinovic, Slobodan; Liu, Yaoming; Gordon, Robert J.; Hanley, Luke

    2012-01-01

    An ultrafast laser ablation time-of-flight mass spectrometer (AToF-MS) and associated data acquisition software that permits imaging at micron-scale resolution and sub-micron-scale depth profiling are described. The ion funnel-based source of this instrument can be operated at pressures ranging from 10−8 to ∼0.3 mbar. Mass spectra may be collected and stored at a rate of 1 kHz by the data acquisition system, allowing the instrument to be coupled with standard commercial Ti:sapphire lasers. The capabilities of the AToF-MS instrument are demonstrated on metal foils and semiconductor wafers using a Ti:sapphire laser emitting 800 nm, ∼75 fs pulses at 1 kHz. Results show that elemental quantification and depth profiling are feasible with this instrument. PMID:23020378

  3. Nondestructive depth profile of the chemical state of ultrathin Al2O3/Si interface

    NASA Astrophysics Data System (ADS)

    Lee, Jong Cheol; Oh, S.-J.

    2004-05-01

    We investigated a depth profile of the chemical states of an Al2O3/Si interface using nondestructive photon energy-dependent high-resolution x-ray photoelectron spectroscopy (HRXPS). The Si 2p binding energy, attributed to the oxide interfacial layer (OIL), was found to shift from 102.1 eV to 102.9 eV as the OIL region closer to Al2O3 layer was sampled, while the Al 2p binding energy remains the same. This fact strongly suggests that the chemical state of the interfacial layer is not Al silicate as previously believed. We instead propose from the HRXPS of Al 2p and Si 2p depth-profile studies that the chemical states of the Al2O3/Si interface mainly consist of SiO2 and Si2O3.

  4. Experimental analysis of bruises in human volunteers using radiometric depth profiling and diffuse reflectance spectroscopy

    NASA Astrophysics Data System (ADS)

    Vidovič, Luka; Milanič, Matija; Majaron, Boris

    2015-07-01

    We combine pulsed photothermal radiometry (PPTR) depth profiling with diffuse reflectance spectroscopy (DRS) measurements for a comprehensive analysis of bruise evolution in vivo. While PPTR enables extraction of detailed depth distribution and concentration profiles of selected absorbers (e.g. melanin, hemoglobin), DRS provides information in a wide range of visible wavelengths and thus offers an additional insight into dynamics of the hemoglobin degradation products. Combining the two approaches enables us to quantitatively characterize bruise evolution dynamics. Our results indicate temporal variations of the bruise evolution parameters in the course of bruise self-healing process. The obtained parameter values and trends represent a basis for a future development of an objective technique for bruise age determination.

  5. Chemical depth profiles of the GaAs/native oxide interface

    NASA Technical Reports Server (NTRS)

    Grunthaner, P. J.; Vasquez, R. P.; Grunthaner, F. J.

    1980-01-01

    The final-state oxidation products and their distribution in thin native oxides (30-40 A) on GaAs have been studied using X-ray photoelectron spectroscopy in conjunction with chemical depth profiling. Extended room-temperature-oxidation conditions have been chosen to allow the native oxide to attain its equilibrium composition and structure. The work emphasizes the use of chemical depth-profiling methods which make it possible to examine the variation in chemical reactivity of the oxide structure. A minimum of two distinct regions of Ga2O3 with differing chemical reactivity is observed. Chemical shift data indicate the presence of As2O3 in the oxide together with an elemental As overlayer at the interface. A change in relative charge transfer between oxygen and both arsenic and gallium-oxide species is observed in the region of the interface.

  6. Quantitative depth profiling of light elements by means of the ERD E × B technique

    NASA Astrophysics Data System (ADS)

    Schiettekatte, F.; Chevarier, A.; Chevarier, N.; Plantier, A.; Ross, G. G.

    1996-09-01

    ERDA [J. L'Écuyer et al., J. Appl. Phys. 47 (1976) 381] is a technique of great interest for quantitative depth profiling of light elements in matter. The use of crossed electric and magnetic fields ( E × B filter) [G.G. Ross et al. J. Nucl. Mater. 128/129 (1992) 484; G.G. Ross and L. Leblanc, Nucl. Instr. and Meth. B 62 (1992) 484] in place of the traditional absorber, enhances the resolution by eliminating the straggling induced normally by the absorber and removes the uncertainty on the absorber thickness. The E × B filter allows the simultaneous detection of different particles such as H, D and He. This work presents the first ERD E × B depth profiling by means of a heavy ion beam. Compared with the usual ERD E × B with 350 keV He, the 2.54 MeV 15N beam enhances scattering cross section by a factor of 3, has equivalent depth resolution (1-3 nm at surface) and gives a depth probe twice deeper. However, 15N ions sometimes induce high desorption compared to He. H, D and He were implanted in Be and Si at energies from 800 eV to 10 keV. The experimental depth distributions are compared with those obtained by TRIM95 [J.F. Ziegler and J.P. Biersack, The Stopping and Range of Ions in Solids (Pergamon, New York, 1995)] and by other experimental techniques. Reproducibility is very good between the different results obtained experimentally. Profile modification induced by the ion beam is also shown.

  7. Threading Dislocation Characterization and Stress Mapping Depth Profiling via Ray Tracing Technique

    NASA Astrophysics Data System (ADS)

    Zhou, Tianyi

    Zinc oxide (ZnO) has been well known as a transparent, dielectric, piezoelectric and wide band gap material. The potential capabilities have been demonstrated for a wide range of applications such as piezoelectric transducer, gas sensor, optical waveguides and transparent electrode. It could also be applied as a substrate material for GaN-based devices. However, while some applications have already been realized, issues relating to crystalline defects remain a barrier to the successful realization of several others. In this thesis, the central focus of Chapter II is to characterize threading dislocations in hydrothermal grown ZnO substrates through simulation work as well as other techniques. The goal of this study is to find the origin of threading dislocations and design strategies to mitigate their negative effects by either reducing their densities or completely eliminating them. In Chapter III, the technique of SMART (stress mapping analysis via ray tracing) is discussed in detail to measure residue stress in packaged silicon circuits. Residual stress plays an important role in the performance and lifetime of single crystal device material. There are mainly two advantages of SMART compared with other techniques: (a) all six components of the stress tensor could be evaluated; (b) it is non-destructive and no damaging trace will be left on the sample. In this study, our goal is to build a relationship between stress distribution and depth. The concept of penetration depth is critically important in this study and its value may cause great changes for real space stress distribution. A new function is applied to get better fitting curves. Data in this study is obtained from various penetration depth, which represents exponentially decaying weighted average of actual stress value or in other words this stress profile is Laplace transform of real stress profile. Mathematical procedure is described to determine real stress profile from Laplace profile. Experiment

  8. Dating a tropical ice core by time-frequency analysis of ion concentration depth profiles

    NASA Astrophysics Data System (ADS)

    Gay, M.; De Angelis, M.; Lacoume, J.-L.

    2014-09-01

    Ice core dating is a key parameter for the interpretation of the ice archives. However, the relationship between ice depth and ice age generally cannot be easily established and requires the combination of numerous investigations and/or modelling efforts. This paper presents a new approach to ice core dating based on time-frequency analysis of chemical profiles at a site where seasonal patterns may be significantly distorted by sporadic events of regional importance, specifically at the summit area of Nevado Illimani (6350 m a.s.l.), located in the eastern Bolivian Andes (16°37' S, 67°46' W). We used ion concentration depth profiles collected along a 100 m deep ice core. The results of Fourier time-frequency and wavelet transforms were first compared. Both methods were applied to a nitrate concentration depth profile. The resulting chronologies were checked by comparison with the multi-proxy year-by-year dating published by de Angelis et al. (2003) and with volcanic tie points. With this first experiment, we demonstrated the efficiency of Fourier time-frequency analysis when tracking the nitrate natural variability. In addition, we were able to show spectrum aliasing due to under-sampling below 70 m. In this article, we propose a method of de-aliasing which significantly improves the core dating in comparison with annual layer manual counting. Fourier time-frequency analysis was applied to concentration depth profiles of seven other ions, providing information on the suitability of each of them for the dating of tropical Andean ice cores.

  9. NEXAFS Depth Profiling of Surface Segregation in Block Copolymer Thin Films

    SciTech Connect

    Krishnan, S.; Paik, M; Ober, C; Martinelli, E; Galli, G; Sohn, K; Kramer, E; Fischer, D

    2010-01-01

    NEXAFS spectroscopy was used to probe the surface composition and under-water surface reconstruction of thin films of comb-like diblock copolymers with cylindrical and spherical microphases. The polymers consisted of a polystyrene block, and a second block prepared from a styrenic monomer grafted with fluoroalkyl-tagged poly(ethylene glycol) side chains. Compositional depth profiling of the microphase separated block copolymer films, in the top 1-3 nm of the film, was performed to understand the role of block copolymer microstructure and self-assembly on surface composition. Using experimentally determined concentration profiles, the surface concentration of phenyl ring carbon atoms was quantified and compared with those of homopolymer and random copolymer controls. The carbon atoms from the relatively high surface energy phenyl groups were depleted or excluded from the surface, in favor of the low surface-energy fluoroalkyl groups. While it is expected that block copolymer surfaces will be completely covered by a wetting lamellar layer of the lower surface energy block, a significant amount of the higher surface energy polystyrene block was found to be present in the surface region of the cylinder-forming block copolymer. Evidently, the spontaneous formation of the cylindrical polystyrene microdomains in the near-surface region compensated for the lowering of the free energy that could have been achieved by completely covering the surfaces with a lamellar layer of the lower surface energy fluorinated block. All surfaces underwent molecular reconstruction after immersion in water. The experimental concentration depth profiles indicated an increased surface depletion of phenyl ring carbon atoms in the water-immersed thin films, due to the tendency of hydrophilic PEG side groups to be present at the polymer-water interface. Such a detailed characterization of the outermost layers of the block copolymer surfaces was possible because of the exceptional depth resolution

  10. Depth profiling of mechanical degradation of PV backsheets after UV exposure

    NASA Astrophysics Data System (ADS)

    Gu, Xiaohong; Krommenhoek, Peter J.; Lin, Chiao-Chi; Yu, Li-Chieh; Nguyen, Tinh; Watson, Stephanie S.

    2015-09-01

    Polymeric multilayer backsheets protect the photovoltaic modules from damage of moisture and ultraviolet (UV) while providing electrical insulation. Due to the multilayer structures, the properties of the inner layers of the backsheets, including their interfaces, during weathering are not well known. In this study, a commercial type of PPE (polyethylene terephthalate (PET)/PET/ethylene vinyl acetate (EVA)) backsheet films was selected as a model system for a depth profiling study of mechanical properties of a backsheet film during UV exposure. The NIST SPHERE (Simulated Photodegradation via High Energy Radiant Exposure) was used for the accelerated laboratory exposure of the materials with UV at 85°C and two relative humidities (RH) of 5 % (dry) and 60 % (humid). Cryomicrotomy was used to obtain cross-sectional PPE samples. Mechanical depth profiling of the cross-sections of aged and unaged samples was conducted by nanoindentation, and a peak-force based quantitative nanomechanical atomic force microscopy (QNM-AFM) mapping techniquewas used to investigate the microstructure and adhesion properties of the adhesive tie layers. The nanoindentation results show the stiffening of the elastic modulus in the PET outer and pigmented EVA layers. From QNM-AFM, the microstructures and adhesion properties of the adhesive layers between PET outer and core layers and between PET core and EVA inner layers are revealed and found to degrade significantly after aging under humidity environment. The results from mechanical depth profiling of the PPE backsheet are further related to the previous chemical depth profiling of the same material, providing new insights into the effects of accelerated UV and humidity on the degradation of multilayer backsheet.

  11. Variations in bacterial and fungal community composition along the soil depth profiles determined by pyrosequencing

    NASA Astrophysics Data System (ADS)

    Ko, D.; Yoo, G.; Jun, S. C.; Yun, S. T.; Chung, H.

    2015-12-01

    Soil microorganisms play key roles in nutrient cycling, and are distributed throughout the soil profile. Currently, there is little information about the characteristics of the microbial communities along the soil depth because most studies focus on microorganisms inhabiting the soil surface. To better understand the functions and composition of microbial communities and the biogeochemical factors that shape them at different soil depth, we analyzed soil microbial activities and bacterial and fungal community composition in a soil profile of a fallow field located in central Korea. Soil samples were taken using 120-cm soil cores. To analyze the composition of bacterial and fungal communities, barcoded pyrosequnecing analysis of 16S rRNA genes (bacteria) and ITS region (fungi) was conducted. Among the bacterial groups, the abundance of Proteobacteria (38.5, 23.2, 23.3, 26.1 and 17.5%, at 15-, 30-, 60-, 90-, and 120-cm depth, respectively) and Firmicutes (12.8, 11.3, 8.6, 4.3 and 0.4%, at 15-, 30-, 60-, 90-, and 120-cm depth, respectively) decreased with soil depth. On the other hand, the abundance of Ascomycota (51.2, 48.6, 65.7, 46.1, and 45.7%, at 15-, 30-, 60-, 90-, and 120-cm depth, respectively), a dominant fungal group at this site, showed no significant difference along the soil profile. To examine the vertical difference of microbial activities, activity of five extracellular enzymes that take part in cycling of C, N, and P in soil ecosystems, beta-1,4-glucosidase, cellobiohydrolase, beta-1,4-xylosidase, beta-1,4-N-acetylglucosaminidase, and acid phosphatase were analyzed. The soil enzyme activity declined with soil depth. For example, acid phosphatase activity was 88.5 (± 14.6 (± 1 SE)), 30.0 (± 5.9), 18.0 (± 3.5), 14.1 (± 3.7), and 10.7 (± 3.8) nmol g-1 hr-1, at 15-, 30-, 60-, 90-, and 120-cm depth, respectively. These metagenomics studies, along with other studies on microbial functions, are expected to enhance our understanding on the complexity of

  12. Comparison of spherical aberration and small pupil profiles in improving depth of focus for presbyopic corrections

    PubMed Central

    Hickenbotham, Adam; Tiruveedhula, Pavan; Roorda, Austin

    2012-01-01

    PURPOSE To compare the validity and effectiveness of 2 methods for expanding depth of focus to correct for presbyopia; that is, induction of spherical aberration and small pupil apertures. SETTING University of California, Berkeley, California, USA. DESIGN Comparative case series. METHODS A random 4-alternative forced-choice acuity task was performed. Visual performance and depth of focus was compared using adaptive optics–corrected distance visual acuity (CDVA) values and mean visual acuity over a 3.0 diopter (D) range of defocus using the following 3 adaptive optics–corrected profiles: 2.0 mm pupil, 5.0 mm pupil, and 5.0 mm pupil with −0.274 µm of spherical aberration. RESULTS The study enrolled 13 subjects. The 5.0 mm pupil profile had a CDVA of −0.218 logMAR and a mean visual acuity through focus of 0.156 logMAR. The 2.0 mm pupil profile had a worse CDVA (0.012 logMAR) but an improved mean visual acuity (0.061 logMAR). The 5.0 mm pupil profile with −0.274 µm of spherical aberration measured a CDVA of −0.082 logMAR and a mean visual acuity 0.103 logMAR. CONCLUSIONS The spherical aberration and small-pupil profiles improved the mean visual acuity across a 3.0 D range of defocus but resulted in decreased CDVA at the plane of best focus in comparison to an adaptive optics–corrected 5.0 mm pupil. Small-pupil profiles are a better choice than spherical aberration profiles for presbyopic corrections due to expected accuracy, predictability, and patient satisfaction. PMID:23031641

  13. Depth profiling of polishing-induced contamination on fused silica surfaces

    SciTech Connect

    Kozlowski, M.R.; Carr, J.; Hutcheon, I,; Torres, R.; Sheehan, L. Camp, D.; Yan, M.

    1997-12-20

    Laser-induced damage on optical surfaces is often associated with absorbing contaminants introduced by the polishing process. This is particularly the case for UV optics. Here secondary ion mass spectroscopy (SIMS) was used to measure depth profiles of finished process contamination on fused silica surfaces. Contaminants detected include the major polishing compound components (Ce or Zr from CeO2 or ZrO2), Al presently largely because of the use of Al2O3 in the final cleaning process (Fe, Cu,Cr) incorporated during the polishing step or earlier grinding steps. Depth profile data typically showed an exponential decay of contaminant concentration to a depth of 100-200 nm. This depth is consistent with a polishing redeposition layers formed during the chemo-mechanical polishing of fused silica. Peak contaminant levels are typically in the 10-100 ppm range, except for Al with exceeds 1000 ppm. A strong correlation has been shown between the presence of a gray haze damage morphology and the use of CeO2 polishing compound. No strong correlation was found however between high levels of Ce, or any other contaminant and the low damage threshold was observed. In fact one of the strongest indications of a correlation is between increased damage thresholds and increased Zr contamination. This suggests that the correlation between redeposition layer and laser damage threshold is not simple an absorbing contaminant issue.

  14. Chemical state of Ag in Conducting Bridge Random Access Memory cells: a depth resolved X-ray Absorption Spectroscopy investigation.

    NASA Astrophysics Data System (ADS)

    d'Acapito, F.; Souchier, E.; Noe, P.; Blaise, P.; Bernard, M.; Jousseaume, V.

    2016-05-01

    Conducting Bridge Random Access Memories (CBRAM) are a promising substitute for FLASH technology but problems with limited retention of the low resistance ON state still hamper their massive deployment. Depth resolved X-ray Absorption Spectroscopy has been used to describe the chemical state of the atoms of the active electrode (in this case Ag) and to reveal the role of Sb as stabilizer of the metallic state.

  15. Spectra from 2.5-15 microm of tissue phantom materials, optical clearing agents and ex vivo human skin: implications for depth profiling of human skin.

    PubMed

    Viator, John A; Choi, Bernard; Peavy, George M; Kimel, Sol; Nelson, J Stuart

    2003-01-21

    Infrared measurements have been used to profile or image biological tissue, including human skin. Usually, analysis of such measurements has assumed that infrared absorption is due to water and collagen. Such an assumption may be reasonable for soft tissue, but introduction of exogenous agents into skin or the measurement of tissue phantoms has raised the question of their infrared absorption spectrum. We used Fourier transform infrared spectroscopy in attenuated total reflection mode to measure the infrared absorption spectra, in the range of 2-15 microm, of water, polyacrylamide, Intralipid, collagen gels, four hyperosmotic clearing agents (glycerol, 1,3-butylene glycol, trimethylolpropane, Topicare), and ex vivo human stratum corneum and dermis. The absorption spectra of the phantom materials were similar to that of water, although additional structure was noted in the range of 6-10 microm. The absorption spectra of the clearing agents were more complex, with molecular absorption bands dominating between 6 and 12 microm. Dermis was similar to water, with collagen structure evident in the 6-10 microm range. Stratum corneum had a significantly lower absorption than dermis due to a lower content of water. These results suggest that the assumption of water-dominated absorption in the 2.5-6 microm range is valid. At longer wavelengths, clearing agent absorption spectra differ significantly from the water spectrum. This spectral information can be used in pulsed photothermal radiometry or utilized in the interpretation of reconstructions in which a constant mu(ir) is used. In such cases, overestimating mu(ir) will underestimate chromophore depth and vice versa, although the effect is dependent on actual chromophore depth. PMID:12587910

  16. Implication of Land Use and Belowground Weather on Nitrous Oxide Soil Depth Profiles and Denitrification Potential

    NASA Astrophysics Data System (ADS)

    Phillips, R. L.; Song, B.; Saliendra, N.; Liebig, M. A.

    2013-12-01

    oxygen profiles followed similar patterns for cropland and prairie, ranging from 12 to 21%, with median values of 19 and 20% at both depths. We did not observe linear concentration gradients between 15 and 90 cm depths, likely due to differences in rates of production and consumption throughout the soil profile. Potential rates of denitrification at 0-15 cm were over two times higher in the cropland, as compared to prairie. We conclude that N2O production occurs not only close to the surface but also nearly a meter beneath both undisturbed prairie and cropland. Greater surface fluxes and N2O concentrations at all depths in the cropland under variable conditions point to enhanced N2O production in the absence of synthetic N addition from 2009-2013. While denitrification potential in the laboratory was greater beneath this alfalfa field, the soil oxygen profile measurements indicated conditions favorable for complete denitrification of N to N2 were rare at near-surface and sub-surface soil depths. Microbial N2O production and consumption processes vary with soil depth and land use in the absence of synthetic N inputs, and further investigation is warranted.

  17. Simulation and measurement of AES depth profiles; a case study of the C/Ta/C/Si system

    NASA Astrophysics Data System (ADS)

    Zommer, Ludomir; Jablonski, Alexander; Kotis, László; Safran, Gyorgy; Menyhárd, Miklós

    2010-04-01

    A multilayer sample (C (23.3 nm)/Ta (26.5 nm)/C (22.7 nm)/Si substrate) was submitted to AES depth profiling by Ar + ions of energy 1 keV and angles of incidence of 72°, 78°, and 82°. The shapes of the as-measured depth profiles were strongly different emphasizing that the ion-bombardment conditions strongly affects the shapes of measured depth profiles. We simulated the depth profile measured at an angle of incidence of 72° by calculating the backscattering factor, applying attenuation lengths available in the literature, and simulating the ion-bombardment-induced specimen alteration with a TRIDYN simulation and a trial and error method. The good agreement between the calculated and measured depth profiles justified the method applied.

  18. Direct evidence for anisotropic He diffusivity in zircon provided by laser depth profiling (Invited)

    NASA Astrophysics Data System (ADS)

    Hodges, K.; van Soest, M. C.; Monteleone, B. D.; Boyce, J. W.

    2009-12-01

    While zircon (U-Th)/He dating has become an increasingly popular tool for studies of the thermal evolution of orogenic systems, several issues complicate interpretations of the geologic significance of zircon “dates”. Zircons frequently exhibit complex U-Th zoning, which makes corrections for alpha ejection loss uncertain. It has been known for decades that radiation damage enhances the rate of diffusive loss of helium in zircon, sometimes making the unique assignment of a (U-Th)/He closure temperature difficult. Here we consider another complicating factor: the proposal by Reich et al. (2007) - based on computer simulations - that He diffusion is anisotropic in zircon, which also may have significant implications regarding (U-Th)/He closure temperature. We present, for the first time, direct measurements of crystallographically controlled, anisotropic diffusion profiles in zircon that appear to support the conclusions of Reich et al. (2007). For this study, we conducted replicate vacuum heating experiments on slices from euhedral crystals of Cretaceous De Beers zircon from South Africa and Proterozoic Mud Tank zircon from Australia. (All slices were cut from the central portions of very large crystals in order to avoid natural alpha ejection profiles near crystal margins.) In each experiment, we heated slices of the two zircons cut both parallel and perpendicular to their c-axes for 24 hours at 415° C. Depth profiling of the resulting 4He diffusion profiles using an ArF excimer laser revealed extremely similar c-axis parallel diffusion profiles for both zircons, and extremely similar c-axis perpendicular diffusion profiles for both zircons. However, the c-axis parallel and perpendicular profiles were markedly different. The loss profiles parallel to c extended over twice as far into the crystals as did the perpendicular profiles, implying much more rapid thermally activated diffusion parallel to the c direction, as predicted by the Reich et al. models

  19. A method of rapidly obtaining concentration-depth profiles from X-ray diffraction

    NASA Technical Reports Server (NTRS)

    Wiedemann, K. E.; Unnam, J.

    1985-01-01

    A broadened diffraction peak, or intensity band, is observed in the case diffraction from a nonhomogeneous phase in which the variations in compositions result in a range of lattice spacings. An intriguing aspect regarding the relationship between the X-ray diffraction band and the composition-depth profile is the hypersensitivity of the intensity band to the shape of the profile. A number of investigators have sought to use this sensitivity to construct high-precision profiles. Difficulties encountered are related to complications due to intensity broadening, and prohibitive computational requirements. Simulation techniques have provided the most accurate interpretation of the intensity band. However, the involved calculations have been prohibitively long. The present study discusses a technique which has simple computational requirements and is as accurate and flexible as the simulation techniques.

  20. Technical note: A bootstrapped LOESS regression approach for comparing soil depth profiles

    NASA Astrophysics Data System (ADS)

    Keith, Aidan M.; Henrys, Peter A.; Rowe, Rebecca L.; McNamara, Niall P.

    2016-07-01

    Understanding the consequences of different land uses for the soil system is important to make better informed decisions based on sustainability. The ability to assess change in soil properties, throughout the soil profile, is a critical step in this process. We present an approach to examine differences in soil depth profiles between land uses using bootstrapped LOESS regressions (BLRs). This non-parametric approach is data-driven, unconstrained by distributional model parameters and provides the ability to determine significant effects of land use at specific locations down a soil profile. We demonstrate an example of the BLR approach using data from a study examining the impacts of bioenergy land use change on soil organic carbon (SOC). While this straightforward non-parametric approach may be most useful in comparing SOC profiles between land uses, it can be applied to any soil property which has been measured at satisfactory resolution down the soil profile. It is hoped that further studies of land use and land management, based on new or existing data, can make use of this approach to examine differences in soil profiles.

  1. Technical note: A new approach for comparing soil depth profiles using bootstrapped Loess regression (BLR)

    NASA Astrophysics Data System (ADS)

    Keith, A. M.; Henrys, P.; Rowe, R. L.; McNamara, N. P.

    2015-12-01

    Understanding the consequences of different land uses for the soil system is important to better inform decisions based on sustainability. The ability to assess change in soil properties, throughout the soil profile, is a critical step in this process. We present an approach to examine differences in soil depth profiles between land uses using bootstrapped Loess regressions (BLR). This non-parametric approach is data-driven, unconstrained by distributional model parameters and provides the ability to determine significant effects of land use at specific locations down a soil profile. We demonstrate an example of the BLR approach using data from a study examining the impacts of bioenergy land use change on soil carbon (C). While this straightforward non-parametric approach may be most useful in comparing soil C or organic matter profiles between land uses, it can be applied to any soil property which has been measured at satisfactory resolution down the soil profile. It is hoped that further studies of land use and land management, based on new or existing data, can make use of this approach to examine differences in soil profiles.

  2. Tracking water pathways in steep hillslopes by δ18O depth profiles of soil water

    NASA Astrophysics Data System (ADS)

    Mueller, Matthias H.; Alaoui, Abdallah; Kuells, Christoph; Leistert, Hannes; Meusburger, Katrin; Stumpp, Christine; Weiler, Markus; Alewell, Christine

    2014-11-01

    Assessing temporal variations in soil water flow is important, especially at the hillslope scale, to identify mechanisms of runoff and flood generation and pathways for nutrients and pollutants in soils. While surface processes are well considered and parameterized, the assessment of subsurface processes at the hillslope scale is still challenging since measurement of hydrological pathways is connected to high efforts in time, money and personnel work. The latter might not even be possible in alpine environments with harsh winter processes. Soil water stable isotope profiles may offer a time-integrating fingerprint of subsurface water pathways. In this study, we investigated the suitability of soil water stable isotope (δ18O) depth profiles to identify water flow paths along two transects of steep subalpine hillslopes in the Swiss Alps. We applied a one-dimensional advection-dispersion model using δ18O values of precipitation (ranging from -24.7 to -2.9‰) as input data to simulate the δ18O profiles of soil water. The variability of δ18O values with depth within each soil profile and a comparison of the simulated and measured δ18O profiles were used to infer information about subsurface hydrological pathways. The temporal pattern of δ18O in precipitation was found in several profiles, ranging from -14.5 to -4.0‰. This suggests that vertical percolation plays an important role even at slope angles of up to 46°. Lateral subsurface flow and/or mixing of soil water at lower slope angles might occur in deeper soil layers and at sites near a small stream. The difference between several observed and simulated δ18O profiles revealed spatially highly variable infiltration patterns during the snowmelt periods: The δ18O value of snow (-17.7 ± 1.9‰) was absent in several measured δ18O profiles but present in the respective simulated δ18O profiles. This indicated overland flow and/or preferential flow through the soil profile during the melt period. The applied

  3. {sup 14}C depth profiles in Apollo 15 and 17 cores and lunar rock 68815

    SciTech Connect

    Jull, A.J.T.; Cloudt, S.; Donahue, D.J.; Sisterson, J.M.; Reedy, R.C.; Masarik, J.

    1998-09-01

    Accelerator mass spectrometry (AMS) was used to measure the activity vs. depth profiles of {sup 14}C produced by both solar cosmic rays (SCR) and galactic cosmic rays (GCR) in Apollo 15 lunar cores 15001-6 and 15008, Apollo 17 core 76001, and lunar rock 68815. Calculated GCR production rates are in good agreement with {sup 14}C measurements at depths below {approximately}10 cm. Carbon-14 produced by solar protons was observed in the top few cm of the Apollo 15 cores and lunar rock 68815, with near-surface values as high as 66 dpm/kg in 68815. Only low levels of SCR-produced {sup 14}C were observed in the Apollo 17 core 76001. New cross sections for production of {sup 14}C by proton spallation on O, Si, Al, Mg, Fe, and Ni were measured using AMS. These cross sections are essential for the analysis of the measured {sup 14}C depth profiles. The best fit to the activity-depth profiles for solar-proton-produced {sup 14}C measured in the tops of both the Apollo 15 cores and 68815 was obtained for an exponential rigidity spectral shape R{sub 0} of 110--115 MV and a 4 {pi} flux (J{sub 10}, Ep > 10 MeV) of 103--108 protons/cm{sup 2}/s. These values of R{sub 0} are higher, indicating a harder rigidity, and the solar-proton fluxes are higher than those determined from {sup 10}Be, {sup 26}Al, and {sup 53}Mn measurements.

  4. Acclimation to different depths by the marine angiosperm Posidonia oceanica: transcriptomic and proteomic profiles

    PubMed Central

    Dattolo, Emanuela; Gu, Jenny; Bayer, Philipp E.; Mazzuca, Silvia; Serra, Ilia A.; Spadafora, Antonia; Bernardo, Letizia; Natali, Lucia; Cavallini, Andrea; Procaccini, Gabriele

    2013-01-01

    For seagrasses, seasonal and daily variations in light and temperature represent the mains factors driving their distribution along the bathymetric cline. Changes in these environmental factors, due to climatic and anthropogenic effects, can compromise their survival. In a framework of conservation and restoration, it becomes crucial to improve our knowledge about the physiological plasticity of seagrass species along environmental gradients. Here, we aimed to identify differences in transcriptomic and proteomic profiles, involved in the acclimation along the depth gradient in the seagrass Posidonia oceanica, and to improve the available molecular resources in this species, which is an important requisite for the application of eco-genomic approaches. To do that, from plant growing in shallow (−5 m) and deep (−25 m) portions of a single meadow, (i) we generated two reciprocal Expressed Sequences Tags (EST) libraries using a Suppressive Subtractive Hybridization (SSH) approach, to obtain depth/specific transcriptional profiles, and (ii) we identified proteins differentially expressed, using the highly innovative USIS mass spectrometry methodology, coupled with 1D-SDS electrophoresis and labeling free approach. Mass spectra were searched in the open source Global Proteome Machine (GPM) engine against plant databases and with the X!Tandem algorithm against a local database. Transcriptional analysis showed both quantitative and qualitative differences between depths. EST libraries had only the 3% of transcripts in common. A total of 315 peptides belonging to 64 proteins were identified by mass spectrometry. ATP synthase subunits were among the most abundant proteins in both conditions. Both approaches identified genes and proteins in pathways related to energy metabolism, transport and genetic information processing, that appear to be the most involved in depth acclimation in P. oceanica. Their putative rules in acclimation to depth were discussed. PMID:23785376

  5. Observed damage during Argon gas cluster depth profiles of compound semiconductors

    SciTech Connect

    Barlow, Anders J. Portoles, Jose F.; Cumpson, Peter J.

    2014-08-07

    Argon Gas Cluster Ion Beam (GCIB) sources have become very popular in XPS and SIMS in recent years, due to the minimal chemical damage they introduce in the depth-profiling of polymer and other organic materials. These GCIB sources are therefore particularly useful for depth-profiling polymer and organic materials, but also (though more slowly) the surfaces of inorganic materials such as semiconductors, due to the lower roughness expected in cluster ion sputtering compared to that introduced by monatomic ions. We have examined experimentally a set of five compound semiconductors, cadmium telluride (CdTe), gallium arsenide (GaAs), gallium phosphide (GaP), indium arsenide (InAs), and zinc selenide (ZnSe) and a high-κ dielectric material, hafnium oxide (HfO), in their response to argon cluster profiling. An experimentally determined HfO etch rate of 0.025 nm/min (3.95 × 10{sup −2} amu/atom in ion) for 6 keV Ar gas clusters is used in the depth scale conversion for the profiles of the semiconductor materials. The assumption has been that, since the damage introduced into polymer materials is low, even though sputter yields are high, then there is little likelihood of damaging inorganic materials at all with cluster ions. This seems true in most cases; however, in this work, we report for the first time that this damage can in fact be very significant in the case of InAs, causing the formation of metallic indium that is readily visible even to the naked eye.

  6. Matrix effect-free depth profiling of multilayered Si/Ti with laser-SNMS

    NASA Astrophysics Data System (ADS)

    Nishinomiya, Suguru; Kubota, Naoyoshi; Hayashi, Shun-ichi; Takenaka, Hisataka

    2012-07-01

    In order to reveal matrix effect at surface and interfacial regions, we have measured the depth profiles of multilayered Si/Ti by secondary ion mass spectrometry (SIMS) and resonance-enhanced multiphoton ionization sputtered neutral mass spectrometry (REMPI-SNMS) using Ar+ beam as primary ion beam. Titanium profile of SIMS was strongly influenced with matrix effect in comparison to silicon one. Especially in the Si/Ti interfacial regions, the Ti+ yield of SIMS was enhanced, whereas the Ti neutral yield of SNMS was proportional to the actual Ti in-depth concentration profile. By means of the XPS measurement, we confirmed the existence of the TiSi2 at these regions. Useful yield of Ti+ sputtered from a TiSi2 sample was about five times larger than that sputtered from a Ti sample which is caused by the difference of chemical state in Ti and TiSi2 bulk. This difference could be interpretable by using the electron tunneling model. On the other hand, useful yield of Ti neutral sputtered from Ti sample was same as that from TiSi2 one. In conclusion, the distribution of the fraction of secondary ion species relating with Ti, such as Ti+, TiO+, TiSi+, etc., was only varied with the change of chemical state in the sample, which caused the matrix effect for the SIMS measurement. We consider the results of both SIMS and SNMS measurements give us the significant knowledge about the mechanism of the matrix effect for depth profile measurement.

  7. Study on the Relationship between the Depth of Spectral Absorption and the Content of the Mineral Composition of Biotite.

    PubMed

    Yang, Chang-bao; Zhang, Chen-xi; Liu, Fang; Jiang, Qi-gang

    2015-09-01

    The mineral composition of rock is one of the main factors affecting the spectral reflectance characteristics, and it's an important reason for generating various rock characteristic spectra. This study choose the rock samples provided by Jet Propulsion Laboratory (JPL) (including all kinds of mineral percentage of rocks, and spectral reflectances range from 0.35 to 2.50 μm wavelength measured by ASD spectrometer), and the various types of mineral spectral reflectances contained within the rocks are the essential data. Using the spectral linear mixture model of rocks and their minerals, firstly, a simulation study on the mixture of rock and mineral composition is achieved, the experimental results indicate that rock spectral curves using the model which based on the theory of the linear mixture are able to simulate better and preserve the absorption characteristics of various mineral components well. Then, 8 samples which contain biotite mineral are picked from the rock spectra of igneous, biotite contents and the absorption depth characteristics of spectral reflection at 2.332 μm, furthermore, a variety of linear and nonlinear normal statistical models are used to fit the relationship between the depth of absorption spectra and the content of the mineral composition of biotite, finally, a new simulation model is build up with the Growth and the Exponential curve model, and a statistical response relationship between the spectral absorption depth and the rock mineral contents is simulated by using the new model, the fitting results show that the correlation coefficient reaches 0.9984 and the standard deviation is 0.572, although the standard deviation using Growth and Exponential model is less than the two model combined with the new model fitting the standard deviation, the correlation coefficient of the new model had significantly increased, which suggesting that the, new model fitting effect is closer to the measured values of samples, it proves that the

  8. Uplifting of palsa peatlands by permafrost identified by stable isotope depth profiles

    NASA Astrophysics Data System (ADS)

    Krüger, Jan Paul; Conen, Franz; Leifeld, Jens; Alewell, Christine

    2015-04-01

    Natural abundances of stable isotopes are a widespread tool to investigate biogeochemical processes in soils. Palsas are peatlands with an ice core and are common in the discontinuous permafrost region. Elevated parts of palsa peatlands, called hummocks, were uplifted by permafrost out of the influence of groundwater. Here we used the combination of δ15N values and C/N ratio along depth profiles to identify perturbation of these soils. In the years 2009 and 2012 we took in total 14 peat cores from hummocks in two palsa peatlands near Abisko, northern Sweden. Peat samples were analysed in 2 to 4 cm layers for stable isotope ratios and concentrations of C and N. The uplifting of the hummocks by permafrost could be detected by stable isotope depth patterns with the highest δ15N value at permafrost onset, a so-called turning point. Regression analyses indicated in 11 of 14 peat cores increasing δ15N values above and decreasing values below the turning point. This is in accordance with the depth patterns of δ13C values and C/N ratios in these palsa peatlands. Onset of permafrost aggradation identified by the highest δ15N value in the profile and calculated from peat accumulation rates show ages ranging from 80 to 545 years and indicate a mean (±SD) peat age at the turning points of 242 (±66) years for Stordalen and 365 (±53) years for Storflaket peatland. The mean peat ages at turning points are within the period of the Little Ice Age. Furthermore, we tested if the disturbance, in this case the uplifting of the peat material, can be displayed in the relation of δ15N and C/N ratio following the concept of Conen et al. (2013). In unperturbed sites soil δ15N values cover a relatively narrow range at any particular C/N ratio. Changes in N cycling, i.e. N loss or gain, results in the loss or gain of 15N depleted forms. This leads to larger or smaller δ15N values than usual at the observed C/N ratio. All, except one, turning point show a perturbation in the depth

  9. Ti-U-Th-Pb Depth Profiles of Hadean Zircons: Implications for the Late Heavy Bombardment

    NASA Astrophysics Data System (ADS)

    Abbott, S. S.; Harrison, M.; Mojzsis, S. J.; Schmitt, A. K.

    2011-12-01

    The Late Heavy Bombardment (LHB) is a hypothesized spike in the flux of bolides that impacted the surface of the moon, and by inference the Earth from 3.8 to 4.0 Ga. Evidence for the LHB comes largely from K-Ar ages of Apollo-era lunar samples interpreted to be ejecta formed during meteorite impacts. Few localities on Earth preserve even a scant terrestrial rock record prior to >4 Ga, which limits the search for terrestrial evidence of the LHB. Perhaps the best accessible record can be found in Hadean detrital zircons from the Jack Hills region of Western Australia, which may provide such evidence in the form of epitaxial rims grown during heating events that might have recorded a thermal signature of impacts. Their preserved isotopic signatures can be used to infer temperature histories that may provide insight into the environmental source conditions during the LHB-era. Specifically, are overgrowths formed under such anomalously high temperatures that we are compelled to infer their growth in response to impact heating during the LHB? This potentially can be resolved by comparing crystallization temperatures of LHB-era zircons to temperature spectra of terrestrial Hadean and impact-formed zircons. Terrestrial Hadean zircons yield apparent crystallization temperatures of 680±25oC whereas impact melt zircons yield higher average temperatures of ca. 780oC. We developed a SIMS method simultaneously combining the empirical Ti-in-zircon thermometry with U-Th-Pb. By depth profiling in this manner, we can obtain continuous depth vs. age and temperature data and thus identify temperatures of sub-μm overgrowths that grew epitaxially on detrital cores. Of the eight Hadean zircons Ti-U-Th-Pb depth profiled in this study, four had rims of LHB-era age. A 2D probability density function of age vs. temperature for the depth profiles shows a bimodal temperature distribution, with generally higher crystallization temperatures for ~3.8-4.0 Ga (i.e., LHB-era) zircon rims (ca.~760

  10. Characterizing contaminant concentrations with depth by using the USGS well profiler in Oklahoma, 2003-9

    USGS Publications Warehouse

    Smith, S. Jerrod; Becker, Carol J.

    2011-01-01

    In 2007, the USGS well profiler was used to investigate saline water intrusion in a deep public-supply well completed in the Ozark (Roubidoux) aquifer. In northeast Oklahoma, where the Ozark aquifer is known to be susceptible to contamination from mining activities, the well profiler also could be used to investigate sources (depths) of metals contamination and to identify routes of entry of metals to production wells.Water suppliers can consider well rehabilitation as a potential remediation strategy because of the ability to identify changes in contaminant concentrations with depth in individual wells with the USGS well profiler. Well rehabilitation methods, which are relatively inexpensive compared to drilling and completing new wells, involve modifying the construction or operation of a well to enhance the production of water from zones with lesser concentrations of a contaminant or to limit the production of water from zones with greater concentrations of a contaminant. One of the most effective well rehabilitation methods is zonal isolation, in which water from contaminated zones is excluded from production through installation of cement plugs or packers. By using relatively simple and inexpensive well rehabilitation methods, water suppliers may be able to decrease exposure of customers to contaminants and avoid costly installation of additional wells, conveyance infrastructure, and treatment technologies.

  11. Sediment mixing and accumulation rate effects on radionuclide depth profiles in Hudson estuary sediments

    SciTech Connect

    Olsen, C.R.; Simpson, H.J.; Peng, T.; Bopp, R.F.; Trier, R.M.

    1981-11-20

    Measured anthropogenic radionuclide profiles in sediment cores from the Hudson River estuary were compared with profiles computed by using known input histories of radionuclides to the estuary and mixing coefficients which decreased exponentially with depth in the sediment. Observed /sup 134/Cs sediment depth profiles were used in the mixing rate computation because reactor releases were the only significant source for this nuclide, whereas the inputs of /sup 137/Cs and /sup 239.240/Pu to the estuary were complicated by runoff or erosion in upstream areas, in addition to direct fallout from precipitation. Our estimates for the rates of surface sediment mixing in the low salinity reach of the estuary range from 0.25 to 1 cm/sup 2//yr, or less. In some areas of the harbor adjacent to New York City, were fine-particle accumulation rates are generally >3 cm/yr, and often as high as 10 to 20 cm/yr, sediment mixing rates as high as 10 cm/sup 2//yr would have little effect on radionuclide peak distributions. Consequently, anthropogenic radionuclide maximum activities in subsurface sediments of the Hudson appear to be useful as time-stratigraphic reference levels, which can be correlated with periods of maximum radionuclide inputs for estimating rates and patterns of sediment accumulation.

  12. Modelling Rooting Depth and Soil Strength in a Drying Soil Profile

    PubMed

    Bengough

    1997-06-01

    A combined root growth and water extraction model is described that simulates the affects of mechanical impedance on root elongation in soil. The model simulates the vertical redistribution of water in the soil profile, water uptake by plant roots, and the effects of decreasing water content on increasing soil strength and decreasing the root elongation rate. The modelling approach is quite general and can be applied to any soil for which a relation can be defined between root elongation and penetrometer resistance. By definition this excludes soils that contain a large proportion of continuous channels through which roots can grow unimpeded. Root elongation rate is calculated as a function of the penetrometer resistance which is determined by the soil water content. Use of the model is illustrated using input data for a sandy loam soil. The results confirm reports in the literature that the depth of water extraction can exceed the rooting depth. The increase in mechanical impedance to root growth due to this water extraction restricted the maximum rooting depth attained, and this limited the depth of soil from which a crop could extract water and nutrients. This study highlighted the lack of published data sets for single crop/soil combinations containing both the strength/root growth information and the hydraulic conductivity characteristics necessary for this type of model. Copyright 1997 Academic Press Limited PMID:9344728

  13. Peat soil organic matter composition depth profiles - is the diplotelmic model real?

    NASA Astrophysics Data System (ADS)

    Boothroyd, Ian; Clay, Gareth; Moody, Catherine; Archer, Elaine; Dixon, Simon; Worrall, Fred

    2016-04-01

    Measures of bulk density and organic matter composition provide important insights into peat formation, degradation and hydrology as well as carbon and nutrient cycles, and indeed underpin the diplotelmic model of peat formation. This study presents soil core data from 23 upland and lowland peat sites across the United Kingdom. A series of soil cores up to ~3m depth were analysed for bulk density, gross heat value (energy content) and carbon, hydrogen, nitrogen and oxygen composition. Atomic ratios of C/N, H/C and O/C were used as indicators of the origin and quality of soil organic matter. Results show no consistent soil depth profiles evident across multiple sites, this challenges whether historical interpretations of peat soil formation and structure are appropriate.

  14. Secondary ion mass spectroscopy depth profiling of hydrogen-intercalated graphene on SiC

    NASA Astrophysics Data System (ADS)

    Michałowski, Paweł Piotr; Kaszub, Wawrzyniec; Merkulov, Alexandre; Strupiński, Włodek

    2016-07-01

    For a better comprehension of hydrogen intercalation of graphene grown on a silicon carbide substrate, an advanced analytical technique is required. We report that with a carefully established measurement procedure it is possible to obtain a reliable and reproducible depth profile of bi-layer graphene (theoretical thickness of 0.69 nm) grown on the silicon carbide substrate by the Chemical Vapor Deposition method. Furthermore, we show that with depth resolution as good as 0.2 nm/decade, both hydrogen coming from the intercalation process and organic contamination can be precisely localized. As expected, hydrogen was found at the interface between graphene and the SiC substrate, while organic contamination was accumulated on the surface of graphene and did not penetrate into it. Such a precise measurement may prove to be invaluable for further characterization of 2D materials.

  15. Stable carbon isotope depth profiles and soil organic carbon dynamics in the lower Mississippi Basin

    USGS Publications Warehouse

    Wynn, J.G.; Harden, J.W.; Fries, T.L.

    2006-01-01

    Analysis of depth trends of 13C abundance in soil organic matter and of 13C abundance from soil-respired CO2 provides useful indications of the dynamics of the terrestrial carbon cycle and of paleoecological change. We measured depth trends of 13C abundance from cropland and control pairs of soils in the lower Mississippi Basin, as well as the 13C abundance of soil-respired CO2 produced during approximately 1-year soil incubation, to determine the role of several candidate processes on the 13C depth profile of soil organic matter. Depth profiles of 13C from uncultivated control soils show a strong relationship between the natural logarithm of soil organic carbon concentration and its isotopic composition, consistent with a model Rayleigh distillation of 13C in decomposing soil due to kinetic fractionation during decomposition. Laboratory incubations showed that initially respired CO 2 had a relatively constant 13C content, despite large differences in the 13C content of bulk soil organic matter. Initially respired CO2 was consistently 13C-depleted with respect to bulk soil and became increasingly 13C-depleted during 1-year, consistent with the hypothesis of accumulation of 13C in the products of microbial decomposition, but showing increasing decomposition of 13C-depleted stable organic components during decomposition without input of fresh biomass. We use the difference between 13C / 12C ratios (calculated as ??-values) between respired CO 2 and bulk soil organic carbon as an index of the degree of decomposition of soil, showing trends which are consistent with trends of 14C activity, and with results of a two-pooled kinetic decomposition rate model describing CO2 production data recorded during 1 year of incubation. We also observed inconsistencies with the Rayleigh distillation model in paired cropland soils and reasons for these inconsistencies are discussed. ?? 2005 Elsevier B.V. All rights reserved.

  16. Atmospheric pressure and temperature profiling using near IR differential absorption lidar

    NASA Technical Reports Server (NTRS)

    Korb, C. L.; Schwemmer, G. K.; Dombrowski, M.; Weng, C. Y.

    1983-01-01

    The present investigation is concerned with differential absorption lidar techniques for remotely measuring the atmospheric temperature and pressure profile, surface pressure, and cloud top pressure-height. The procedure used in determining the pressure is based on the conduction of high-resolution measurements of absorption in the wings of lines in the oxygen A band. Absorption with respect to these areas is highly pressure sensitive in connection with the mechanism of collisional line broadening. The method of temperature measurement utilizes a determination of the absorption at the center of a selected line in the oxygen A band which originates from a quantum state with high ground state energy.

  17. Similarity normalization method for thermal conductivity depth profile reconstructions from inhomogeneous cylindrical and flat solids using thermal waves

    NASA Astrophysics Data System (ADS)

    Liu, Liwang; Wang, Chinhua; Yuan, Xiao; Mandelis, Andreas

    2010-03-01

    A similarity normalization method for thermal-wave depth profiling of layered and radial continuously varying inhomogeneous thermophysical properties in cylindrical solids is investigated and related to that developed for inhomogeneous flat solids both theoretically and experimentally using photothermal radiometry. The deconvolution of the curvature effect out of the overall thermal-wave field of inhomogeneous cylindrical solids allows conventional rectilinear thermal-wave inverse-problem techniques to be applied to thermal conductivity depth profile reconstructions in layered and inhomogeneous depth-varying cylindrical solids and opens new possibilities for depth profilometry of such solids using existing flat-surface inverse techniques.

  18. Daptomycin versus Friulimicin B: In-Depth Profiling of Bacillus subtilis Cell Envelope Stress Responses▿ †

    PubMed Central

    Wecke, Tina; Zühlke, Daniela; Mäder, Ulrike; Jordan, Sina; Voigt, Birgit; Pelzer, Stefan; Labischinski, Harald; Homuth, Georg; Hecker, Michael; Mascher, Thorsten

    2009-01-01

    The related lipo(depsi)peptide antibiotics daptomycin and friulimicin B show great potential in the treatment of multiply resistant gram-positive pathogens. Applying genome-wide in-depth expression profiling, we compared the respective stress responses of Bacillus subtilis. Both antibiotics target envelope integrity, based on the strong induction of extracytoplasmic function σ factor-dependent gene expression. The cell envelope stress-sensing two-component system LiaRS is exclusively and strongly induced by daptomycin, indicative of different mechanisms of action in the two compounds. PMID:19164157

  19. Daptomycin versus Friulimicin B: in-depth profiling of Bacillus subtilis cell envelope stress responses.

    PubMed

    Wecke, Tina; Zühlke, Daniela; Mäder, Ulrike; Jordan, Sina; Voigt, Birgit; Pelzer, Stefan; Labischinski, Harald; Homuth, Georg; Hecker, Michael; Mascher, Thorsten

    2009-04-01

    The related lipo(depsi)peptide antibiotics daptomycin and friulimicin B show great potential in the treatment of multiply resistant gram-positive pathogens. Applying genome-wide in-depth expression profiling, we compared the respective stress responses of Bacillus subtilis. Both antibiotics target envelope integrity, based on the strong induction of extracytoplasmic function sigma factor-dependent gene expression. The cell envelope stress-sensing two-component system LiaRS is exclusively and strongly induced by daptomycin, indicative of different mechanisms of action in the two compounds. PMID:19164157

  20. Measured depth-dependence of waveguide invariant in shallow water with a summer profile.

    PubMed

    Turgut, Altan; Fialkowski, Laurie T; Schindall, Jeffrey A

    2016-06-01

    Acoustic-intensity striation patterns were measured in the time-frequency domain using an L-shaped array and two simultaneously towed broadband (350-650 Hz) sources at depths above and below the thermocline under summer profile conditions. Distributions of the waveguide invariant parameter β, extracted from the acoustic striation patterns, peak at different values when receivers are above or below the thermocline for a source that is below the thermocline. However, the distributions show similar characteristics when the source is above the thermocline. Experimental results are verified by a numerical analysis of phase slowness, group slowness, and relative amplitudes of acoustic modes. PMID:27369170

  1. The extraction of depth profiles from simulated ARXPS data: From parametric models to regularization methods

    NASA Astrophysics Data System (ADS)

    Palacio, Carlos; Camacho, Gonzalo; García-Rodríguez, Carlos

    2015-12-01

    The extraction of concentration depth profiles from ARXPS data has been carried out using noisy simulated data and two different approaches, using either simple parametric models or general algorithms with Tikhonov regularization schemes. Among the single parametric models the only one that is stable and robust against noise is that using only one parameter, with the uncertainty of the parameter displaying a linear dependence on the input noise level. For Tikhonov regularization schemes, a guide is given to choose the appropriate regularization parameter, which is based on the use of the S-curve in conjunction with the constraints introduced by χ2, and which provides user-independent results.

  2. Nonaqueous chemical depth profiling of YBa2Cu3O(7-x)

    NASA Technical Reports Server (NTRS)

    Vasquez, R. P.; Foote, M. C.; Hunt, B. D.

    1989-01-01

    A nonaqueous solution of Br in absolute ethanol (EtOH) has recently been reported to be effective at removing nonsuperconducting surface species from YBa2Cu3O(7-x) films, leaving the surface close to the ideal stoichiometry. This same etchant is shown here to be an effective bulk etchant in chemical depth profiling through 1-micron-thick films. The Cu remains in the 2 + oxidation state and the stoichiometry, as determined by X-ray photoelectron spectroscopy, is close to ideal and nearly constant throughout the profile, indicating the absence of any large preferential etching effects. The reaction of YBa2Cu3O(7-x) films with HF/EtOH, HCl/EtOH, and I/EtOH solutions is also reported.

  3. Objective characterization of bruise evolution using photothermal depth profiling and Monte Carlo modeling.

    PubMed

    Vidovič, Luka; Milanič, Matija; Majaron, Boris

    2015-01-01

    Pulsed photothermal radiometry (PPTR) allows noninvasive determination of laser-induced temperature depth profiles in optically scattering layered structures. The obtained profiles provide information on spatial distribution of selected chromophores such as melanin and hemoglobin in human skin. We apply the described approach to study time evolution of incidental bruises (hematomas) in human subjects. By combining numerical simulations of laser energy deposition in bruised skin with objective fitting of the predicted and measured PPTR signals, we can quantitatively characterize the key processes involved in bruise evolution (i.e., hemoglobin mass diffusion and biochemical decomposition). Simultaneous analysis of PPTR signals obtained at various times post injury provides an insight into the variations of these parameters during the bruise healing process. The presented methodology and results advance our understanding of the bruise evolution and represent an important step toward development of an objective technique for age determination of traumatic bruises in forensic medicine. PMID:25554972

  4. Objective characterization of bruise evolution using photothermal depth profiling and Monte Carlo modeling

    NASA Astrophysics Data System (ADS)

    Vidovič, Luka; Milanič, Matija; Majaron, Boris

    2015-01-01

    Pulsed photothermal radiometry (PPTR) allows noninvasive determination of laser-induced temperature depth profiles in optically scattering layered structures. The obtained profiles provide information on spatial distribution of selected chromophores such as melanin and hemoglobin in human skin. We apply the described approach to study time evolution of incidental bruises (hematomas) in human subjects. By combining numerical simulations of laser energy deposition in bruised skin with objective fitting of the predicted and measured PPTR signals, we can quantitatively characterize the key processes involved in bruise evolution (i.e., hemoglobin mass diffusion and biochemical decomposition). Simultaneous analysis of PPTR signals obtained at various times post injury provides an insight into the variations of these parameters during the bruise healing process. The presented methodology and results advance our understanding of the bruise evolution and represent an important step toward development of an objective technique for age determination of traumatic bruises in forensic medicine.

  5. Airborne imaging spectrometer data of the Ruby Mountains, Montana: Mineral discrimination using relative absorption band-depth images

    USGS Publications Warehouse

    Crowley, J.K.; Brickey, D.W.; Rowan, L.C.

    1989-01-01

    Airborne imaging spectrometer data collected in the near-infrared (1.2-2.4 ??m) wavelength range were used to study the spectral expression of metamorphic minerals and rocks in the Ruby Mountains of southwestern Montana. The data were analyzed by using a new data enhancement procedure-the construction of relative absorption band-depth (RBD) images. RBD images, like bandratio images, are designed to detect diagnostic mineral absorption features, while minimizing reflectance variations related to topographic slope and albedo differences. To produce an RBD image, several data channels near an absorption band shoulder are summed and then divided by the sum of several channels located near the band minimum. RBD images are both highly specific and sensitive to the presence of particular mineral absorption features. Further, the technique does not distort or subdue spectral features as sometimes occurs when using other data normalization methods. By using RBD images, a number of rock and soil units were distinguished in the Ruby Mountains including weathered quartz - feldspar pegmatites, marbles of several compositions, and soils developed over poorly exposed mica schists. The RBD technique is especially well suited for detecting weak near-infrared spectral features produced by soils, which may permit improved mapping of subtle lithologic and structural details in semiarid terrains. The observation of soils rich in talc, an important industrial commodity in the study area, also indicates that RBD images may be useful for mineral exploration. ?? 1989.

  6. Analysis of airborne imaging spectrometer data for the Ruby Mountains, Montana, by use of absorption-band-depth images

    NASA Technical Reports Server (NTRS)

    Brickey, David W.; Crowley, James K.; Rowan, Lawrence C.

    1987-01-01

    Airborne Imaging Spectrometer-1 (AIS-1) data were obtained for an area of amphibolite grade metamorphic rocks that have moderate rangeland vegetation cover. Although rock exposures are sparse and patchy at this site, soils are visible through the vegetation and typically comprise 20 to 30 percent of the surface area. Channel averaged low band depth images for diagnostic soil rock absorption bands. Sets of three such images were combined to produce color composite band depth images. This relative simple approach did not require extensive calibration efforts and was effective for discerning a number of spectrally distinctive rocks and soils, including soils having high talc concentrations. The results show that the high spectral and spatial resolution of AIS-1 and future sensors hold considerable promise for mapping mineral variations in soil, even in moderately vegetated areas.

  7. The silicate absorption profile in the interstellar medium towards the heavily obscured nucleus of NGC 4418

    NASA Astrophysics Data System (ADS)

    Roche, P. F.; Alonso-Herrero, A.; Gonzalez-Martin, O.

    2015-05-01

    The 9.7-μm silicate absorption profile in the interstellar medium (ISM) provides important information on the physical and chemical composition of interstellar dust grains. Measurements in the Milky Way have shown that the profile in the diffuse ISM is very similar to the amorphous silicate profiles found in circumstellar dust shells around late M stars, and narrower than the silicate profile in denser star-forming regions. Here, we investigate the silicate absorption profile towards the very heavily obscured nucleus of NGC 4418, the galaxy with the deepest known silicate absorption feature, and compare it to the profiles seen in the Milky Way. Comparison between the 8-13 μm spectrum obtained with Thermal-Region Camera Spectrograph on Gemini and the larger aperture spectrum obtained from the Spitzer archive indicates that the former isolates the nuclear emission, while Spitzer detects low surface brightness circumnuclear diffuse emission in addition. The silicate absorption profile towards the nucleus is very similar to that in the diffuse ISM in the Milky Way with no evidence of spectral structure from crystalline silicates or silicon carbide grains.

  8. Influence of relative abundance of isotopes on depth resolution for depth profiling of metal coatings by laser ablation inductively coupled plasma mass spectrometry.

    PubMed

    Fariñas, Juan C; Coedo, Aurora G; Dorado, Teresa

    2010-04-15

    A systematic study on the influence of relative abundance of isotopes of elements in the coating (A(c)) and in the substrate (A(s)) on both shape of time-resolved signals and depth resolution (Delta z) was performed for depth profile analysis of metal coatings on metal substrates by ultraviolet (266 nm) nanosecond laser ablation inductively coupled plasma quadrupole mass spectrometry. Five coated samples with coating thicknesses of the same order of magnitude (20-30 microm) were tested: nickel coating on aluminium, chromium and copper, and steel coated with copper and zinc. A laser repetition rate of 1 Hz and a laser fluence of 21 J cm(-2) were used. Five different depth profile types were established, which showed a clear dependence on A(c)/A(s) ratio. In general, depth profiles obtained for ratios above 1-10 could not be used to determine Delta z. We found that Delta z increased non-linearly with A(c)/A(s) ratio. The best depth profile types, leading to highest depth resolution and reproducibility, were attained in all cases by using the isotopes with low/medium A(c) values and with the highest A(s) values. In these conditions, an improvement of up to 4 times in Delta z values was achieved. The average ablation rates were in the range from 0.55 microm pulse(-1) for copper coating on steel to 0.83 microm pulse(-1) for zinc coating on steel, and the Delta z values were between 2.74 microm for nickel coating on chromium and 5.91 microm for nickel coating on copper, with RSD values about 5-8%. PMID:20188923

  9. Diffusion of lithium-6 isotopes in lithium aluminate ceramics using neutron depth profiling

    NASA Astrophysics Data System (ADS)

    McWhinney, Hylton G.; James, William D.; Schweikert, Emile A.; Williams, John R.; Hollenberg, Glen; Welsh, John; Sereatan, Washington

    1993-07-01

    Lithium Ceramics offer tremendous potential as a source for the production of tritium ( 3H) for fusion power reactors. Their successful application will depend to a great extent upon the diffusion properties of the 6Li within the matrix. Consequently knowledge od 6Li concentration gradients in the ceramic matrices is an important requirement in the continued development of the technology. In this investigation, the neutron depth profile (NDP) technique has been applied to the study of concentration profiles of 6Li in lithium aluminate ceramics, doped with 1.8%, 50% and 95% 6Li isotopic concentrations. Specimen for analysis were prepared at Battelle (PNL) as pellet discs. Samples for diffusion studies were arranged as diffusion couples in the following manner: 1.8% 6Li discs/85% 6Li powder. Experiments were performed at the Texas A&M Nuclear Science Center Reactor Building, utilizing 1 MW equivalent thermal neutron fluxes 3 × 10 11n/ m2s. The depth probed by the technique is approximately 15 μ.m. Diffusion coefficients are in the range of 2.1 × 10 -12 to 7.0 × 10 -11m2s-1 for 1.8% 6Li-doped ceramics annealed at 1200 and 1400° C, for 4 to 48-h anneal times.

  10. Depth profiling (ICP-MS) study of trace metal 'grains' in solid asphaltenes.

    PubMed

    Pillay, Avin E; Bassioni, Ghada; Stephen, Sasi; Kühn, Fritz E

    2011-08-01

    Knowledge of trace metal 'grains' in asphaltenes could play a significant role in enhancing refining and processing of crudes and also in providing useful information on mechanistic and migratory features linked to asphaltenes. These metals originate directly from interaction of oils with source-rock, mineral matter, and formation water and their accumulation in asphaltene matrices could vary from oil well to oil well. Suitable asphaltene samples were subjected to high-performance ICP-MS laser depth profiling (213 nm) to depths of 50 μm at 5 μm intervals. The study was conducted in the absence of standardization and characteristic intensities originating from the metals of interest were measured. Ten metal profiles were investigated (Na, Mg, Al, Mn, Fe, Zn, Sr, Pb, V, and Ni). The experimental results showed non-uniform distribution of trace metals and identified areas where such metals agglomerate. The data suggested that certain chemical and physical conditions within the structure of asphaltenes are favorable for metal 'grain' formation at specific points. The exact mechanism for this behavior is not clear at this stage, and has considerable scope for future studies, including mathematical modeling simulations of asphaltenes. We also found that solid asphaltenes could be a useful forerunner of scale formation. PMID:21953195

  11. Dual-detection confocal microscopy: high-speed surface profiling without depth scanning

    NASA Astrophysics Data System (ADS)

    Lee, Dong-Ryoung; Gweon, Dae-Gab; Yoo, Hongki

    2016-03-01

    We propose a new method for three-dimensional (3-D) imaging without depth scanning that we refer to as the dual-detection confocal microscopy (DDCM). Compared to conventional confocal microscopy, DDCM utilizes two pinholes of different sizes. DDCM generates two axial response curves which have different stiffness according to the pinhole diameters. The two axial response curves can draw the characteristics curve of the system which shows the relationship between the axial position of the sample and the intensity ratio. Utilizing the characteristic curve, the DDCM reconstructs a 3-D surface profile with a single 2-D scanning. The height of each pixel is calculated by the intensity ratio of the pixel and the intensity ratio curve. Since the height information can be obtained directly from the characteristic curve without depth scanning, a major advantage of DDCM over the conventional confocal microscopy is a speed. The 3-D surface profiling time is dramatically reduced. Furthermore, DDCM can measure 3-D images without the influence of the sample condition since the intensity ratio is independent of the quantum yield and reflectance. We present two types of DDCM, such as a fluorescence microscopy and a reflectance microscopy. In addition, we extend the measurement range axially by varying the pupil function. Here, we demonstrate the working principle of DDCM and the feasibility of the proposed methods.

  12. Analysis of the interface and its position in C60(n+) secondary ion mass spectrometry depth profiling.

    PubMed

    Green, F M; Shard, A G; Gilmore, I S; Seah, M P

    2009-01-01

    C60(n+) ions have been shown to be extremely successful for SIMS depth profiling of a wide range of organic materials, causing significantly less degradation of the molecular information than more traditional primary ions. This work focuses on examining the definition of the interface in a C60(n+) SIMS depth profile for an organic overlayer on a wafer substrate. First it investigates the optimum method to define the organic/inorganic interface position. Variations of up to 8 nm in the interface position can arise from different definitions of the interface position in the samples investigated here. Second, it looks into the reasons behind large interfacial widths, i.e., poor depth resolution, seen in C60(n+) depth profiling. This work confirms that, for Irganox 1010 deposited on a wafer, the depth resolution at the Irganox 1010/substrate interface is directly correlated to the roughening of material. C60n+ PMID:19117445

  13. Non-destructive Measurement of Residual Stress Depth Profile in Laser-peened Steel at SPring-8

    SciTech Connect

    Sato, Masugu; Kajiwara, Kentaro; Sano, Yuji; Tanaka, Hirotomo; Akita, Koichi

    2007-01-19

    We investigated the residual stress depth profile near the surface of steel treated by laser peening without coating using X-ray diffraction at SPring-8. This investigation was carried out using a constant penetration depth sin2{psi} method. In this method, the sin2{psi} diagram is measured controlling both the {psi} angle and the X-ray penetration depth simultaneously with a combination of the {omega} and {chi} axes of the 4-circle goniometer. This method makes it possible to evaluate the residual stress and its depth profile in material with a stress gradient precisely and non-destructively. As a result, we confirmed that a compressive residual stress was successfully formed all over the range of the depth profile in the steel treated properly by laser peening without coating.

  14. Non-destructive Measurement of Residual Stress Depth Profile in Laser-peened Steel at SPring-8

    NASA Astrophysics Data System (ADS)

    Sato, Masugu; Sano, Yuji; Kajiwara, Kentaro; Tanaka, Hirotomo; Akita, Koichi

    2007-01-01

    We investigated the residual stress depth profile near the surface of steel treated by laser peening without coating using X-ray diffraction at SPring-8. This investigation was carried out using a constant penetration depth sin2ψ method. In this method, the sin2ψ diagram is measured controlling both the ψ angle and the X-ray penetration depth simultaneously with a combination of the ω and χ axes of the 4-circle goniometer. This method makes it possible to evaluate the residual stress and its depth profile in material with a stress gradient precisely and non-destructively. As a result, we confirmed that a compressive residual stress was successfully formed all over the range of the depth profile in the steel treated properly by laser peening without coating.

  15. Application of the Optoacoustic Technique to Obtain Depth Profiles of Phantoms of Soft Tissues

    NASA Astrophysics Data System (ADS)

    Reyes-Yépez, M. P.; Cano, M. E.; Vargas-Luna, F. M.; Delgadillo-Holtfort, I.

    2008-08-01

    In this work we implemented an optoacoustic system that uses home-made acoustic transducers having PVDF of 110 μm thickness as piezosensor. The excitation source consisted of a pulsed Nd:YAG at the wavelength of 1064 nm. Soft tissue phantoms of water, gelatin and low-fat milk were used to imitate the optical properties of mammalian tissue. These phantoms were constructed containing an object with enhanced absorption optical properties. These inclusions were used to simulate abnormal tissue within the phantom. With the constructed transducers we were able to detect the inclusions of 1.64 mm thickness using an intensity of about 100 mJ/cm2. The signal coming from the object's edge starts to be detectable at distances that are dependent of both the object's depth and the scattering properties of the phantom.

  16. Dual beam organic depth profiling using large argon cluster ion beams

    PubMed Central

    Holzweber, M; Shard, AG; Jungnickel, H; Luch, A; Unger, WES

    2014-01-01

    Argon cluster sputtering of an organic multilayer reference material consisting of two organic components, 4,4′-bis[N-(1-naphthyl-1-)-N-phenyl- amino]-biphenyl (NPB) and aluminium tris-(8-hydroxyquinolate) (Alq3), materials commonly used in organic light-emitting diodes industry, was carried out using time-of-flight SIMS in dual beam mode. The sample used in this study consists of a ∽400-nm-thick NPB matrix with 3-nm marker layers of Alq3 at depth of ∽50, 100, 200 and 300 nm. Argon cluster sputtering provides a constant sputter yield throughout the depth profiles, and the sputter yield volumes and depth resolution are presented for Ar-cluster sizes of 630, 820, 1000, 1250 and 1660 atoms at a kinetic energy of 2.5 keV. The effect of cluster size in this material and over this range is shown to be negligible. © 2014 The Authors. Surface and Interface Analysis published by John Wiley & Sons Ltd. PMID:25892830

  17. Moho depth variations beneath China continent from deep seismic sounding profiling

    NASA Astrophysics Data System (ADS)

    Teng, Jiwen; Zhang, Zhongjie; Zhang, Yongqian; Pi, Jiaolong; Deng, Yangfan; Zhang, Xiankang; Wang, Chunyong; Gao, Rui; Liu, Cai

    2013-04-01

    Knowledge of Moho depth and crustal structure are required to study and explore the deep process and coupling response of the formation of mountains, basins, rocks and disasters. In the past half century, the geophysicists in China have completed more than 130 seismic refraction and wide-angle reflection profiles with a total length of 60000km and 11 global geosciences transections (GGT) in China. In this study, we aim to make a systematic research into the Moho depth and crustal structure in China based on the data of velocity models of the crust and upper mantle derived from these more than 130 wide-angle seismic profiles acquired in the last 50 years in China and the surrounding areas. With advanced interpolation technique, we obtain Moho map and average P-wave velocity model, and then make the study on the variations in Moho depth and crustal structure in different tectonics in the East Asia. According to our research results, the resultant Moho depth ranges within 10 and 80 km, and is featured with the deepest Moho discontinuity of about 70-85km beneath Tibetan plateau formed by ongoing continent-continent collision; and relatively constant 30-35 km beneath the eastern North China craton enduring destruction of Lithosphere destruction. Also, we analyzed the average crustal thickness of the consolidated crust beneath the three cratons in China, which is characterized by a gradual thickening from east to west with the values of 29~47 km beneath North-China craton (east), 30~56 km beneath Yangtze craton (south) and 42~59 km beneath Tarim craton (west). In addition, there are three major fold tectonic units in the continental domain and the adjacent oceanic areas, namely the Tethyan-Himalayan zone (south and west), the Paleo-Asian zone (northwest and northeast) and the Circum-Pacific zone (east), which in turn are subdivided into 15 orogenic zones. The Moho depth in these 15 orogenic zones is quite different, too.

  18. Estimating the Depth of Stratigraphic Units from Marine Seismic Profiles Using Nonstationary Geostatistics

    SciTech Connect

    Chihi, Hayet; Galli, Alain; Ravenne, Christian; Tesson, Michel; Marsily, Ghislain de

    2000-03-15

    The object of this study is to build a three-dimensional (3D) geometric model of the stratigraphic units of the margin of the Rhone River on the basis of geophysical investigations by a network of seismic profiles at sea. The geometry of these units is described by depth charts of each surface identified by seismic profiling, which is done by geostatistics. The modeling starts by a statistical analysis by which we determine the parameters that enable us to calculate the variograms of the identified surfaces. After having determined the statistical parameters, we calculate the variograms of the variable Depth. By analyzing the behavior of the variogram we then can deduce whether the situation is stationary and if the variable has an anisotropic behavior. We tried the following two nonstationary methods to obtain our estimates: (a) The method of universal kriging if the underlying variogram was directly accessible. (b) The method of increments if the underlying variogram was not directly accessible. After having modeled the variograms of the increments and of the variable itself, we calculated the surfaces by kriging the variable Depth on a small-mesh estimation grid. The two methods then are compared and their respective advantages and disadvantages are discussed, as well as their fields of application. These methods are capable of being used widely in earth sciences for automatic mapping of geometric surfaces or for variables such as a piezometric surface or a concentration, which are not 'stationary,' that is, essentially, possess a gradient or a tendency to develop systematically in space.

  19. Comparison of stable boundary layer depth estimation from sodar and profile mast.

    NASA Astrophysics Data System (ADS)

    Dieudonne, Elsa; Anderson, Philip

    2015-04-01

    The depth of the atmospheric turbulent mixing layer next to the earths surface, hz, is a key parameter in analysis and modeling of the interaction of the atmosphere with the surface. The transfer of momentum, heat, moisture and trace gases are to a large extent governed by this depth, which to a first approximation acts as a finite reservoir to these quantities. Correct estimates of the evolution of hz assists the would allow accurate prognosis of the near-surface accumulation of these variables, that is, wind speed, temperature, humidity and tracer concentration. Measuring hz however is not simple, especially where stable stratification acts to reduce internal mixing, and indeed, it is not clear whether hz is similar for momentum, heat and tracer. Two methods are compared here, to assess their similarity: firstly using acoustic back-scatter is used as an indicator of turbulent strength, the upper limit implying a change to laminar flow and the top of the boundary layer. Secondly, turbulence kinetic energy profiles, TKE(z), are extrapolated to estimate z for TKE(z) = 0, again implying laminar flow. Both techniques have the implied benefit of being able to run continually (via sodar and turbulence mast respectively) with the prospect of continual, autonomous data analysis generating time series of hz. This report examines monostatic sodar echo and sonic anemometer-derived turbulence profile data from Halley Station on the Brunt Ice Shelf Antarctica, during the austral winter of 2003. We report that the two techniques frequently show significant disagreement in estimated depth, and still require manual intervention, but further progress is possible.

  20. 36Cl and41Ca depth profiles in a Hiroshima granite stone and the Dosimetry System 1986

    NASA Astrophysics Data System (ADS)

    Rühm, W.; Kato, K.; Korschinek, G.; Morinaga, H.; Nolte, E.

    1992-06-01

    For the first time a depth profile of the radioisotope41Ca produced by neutrons from the atomic bomb explosion of Hiroshima was measured. The measurements were performed at the Munich Tandem Laboratory via accelerator mass spectrometry. The41Ca depth profile is part of the evaluation to determine the neutron spectrum of the A-bomb which is basis of the Dosimetry System 1986.

  1. Temperature and depth profiles recorded during dives of elephant seals reflect distinct ocean environments

    NASA Astrophysics Data System (ADS)

    Campagna, Claudio; Rivas, Andrés L.; Marin, M. Rosa

    2000-03-01

    Foraging adult southern elephant seals, Mirounga leonina, from Penı´nsula Valdés, Argentina, dive continuously while travelling across the continental shelf towards deep waters of the SW Atlantic. This study attempted to identify distinct ocean environments encountered by these seals during foraging migrations based on bathymetric and water temperature profiles, and to interpret these profiles in terms of mixing and systems of currents. Depth and water temperature were obtained with data loggers carried by 14 diving adult animals during spring (October-December) and summer (February-March) months. Dive depths allowed us to unmistakably differentiate extensive areas of the SW Atlantic: the Patagonian shelf, shelf slope and open waters of the Argentine Basin. Water temperature profiles added further details to the latter general oceanographic areas, and could be related to large-scale oceanographic processes that led to different water column structures. Temperature data reflected the mixing effects of winds and tides in coastal waters, the formation of a thermocline in mid-shelf areas, the northward flow of the sub-antartic Malvinas Current at the edge of the shelf, and the effect of the subtropical Brazil Current further east over deep off-shelf waters. Some of these distinct areas are known for their enhanced primary production associated with frontal systems. The study shows that elephant seals could be useful, low-cost platforms to obtain oceanographic data. Studies that require extensive sampling of physical variables in large areas over long periods of time would benefit from this approach, pending on more precise and frequent locations of animals at sea.

  2. Laser ablation-ICP-MS depth profiling to study ancient glass surface degradation.

    PubMed

    Panighello, Serena; Van Elteren, Johannes T; Orsega, Emilio F; Moretto, Ligia M

    2015-05-01

    In general the analysis of archeological glass represents a challenge for a wide variety of objects because of the presence of physical and/or chemical damage on the surface of the artifact, also known as weathering or corrosion. To retrieve accurate bulk elemental information by laser ablation-inductively coupled plasma-mass spectrometry (ICP-MS), the original, pristine glass needs to be "reached", thereby penetrating the alteration layer which is often more than 10 μm thick. To study this alteration layer the laser was operated in the drilling mode, either with a low (1 Hz) or a high (10 Hz) pulse repetition rate for a period of 50 s yielding detailed spatial information for ca. 20 elements over a shallow depth (ca. 5 μm) or less-detailed spatial information for 50-60 elements over a greater depth (ca. 50 μm). Quantitative elemental depth profiles (in wt%) were obtained with the so-called sum normalization calibration protocol, based on summation of the elements as their oxides to 100 wt%. We were able to associate the increase of SiO2 (in wt%) in the alteration layer to the volumetric mass density change in the glass as a result of depletion of Na2O and K2O. Also the interaction of the number of laser shots with the alteration layer is shown experimentally via depth measurements using profilometry. Chemical and physical changes in four ancient glass artifacts, directly and indirectly measureable by laser drilling, were studied as a function of internal and external factors such as age, composition, and exposure conditions. PMID:25716469

  3. Accurate reconstruction of the thermal conductivity depth profile in case hardened steel

    NASA Astrophysics Data System (ADS)

    Celorrio, Ricardo; Apiñaniz, Estibaliz; Mendioroz, Arantza; Salazar, Agustín; Mandelis, Andreas

    2010-04-01

    The problem of retrieving a nonhomogeneous thermal conductivity profile from photothermal radiometry data is addressed from the perspective of a stabilized least square fitting algorithm. We have implemented an inversion method with several improvements: (a) a renormalization of the experimental data which removes not only the instrumental factor, but the constants affecting the amplitude and the phase as well, (b) the introduction of a frequency weighting factor in order to balance the contribution of high and low frequencies in the inversion algorithm, (c) the simultaneous fitting of amplitude and phase data, balanced according to their experimental noises, (d) a modified Tikhonov regularization procedure has been introduced to stabilize the inversion, and (e) the Morozov discrepancy principle has been used to stop the iterative process automatically, according to the experimental noise, to avoid "overfitting" of the experimental data. We have tested this improved method by fitting theoretical data generated from a known conductivity profile. Finally, we have applied our method to real data obtained in a hardened stainless steel plate. The reconstructed in-depth thermal conductivity profile exhibits low dispersion, even at the deepest locations, and is in good anticorrelation with the hardness indentation test.

  4. Deuterium depth profile quantification in a ASDEX Upgrade divertor tile using secondary ion mass spectrometry

    NASA Astrophysics Data System (ADS)

    Ghezzi, F.; Caniello, R.; Giubertoni, D.; Bersani, M.; Hakola, A.; Mayer, M.; Rohde, V.; Anderle, M.

    2014-10-01

    We present the results of a study where secondary ion mass spectrometry (SIMS) has been used to obtain depth profiles of deuterium concentration on plasma facing components of the first wall of the ASDEX Upgrade tokamak. The method uses primary and secondary standards to quantify the amount of deuterium retained. Samples of bulk graphite coated with tungsten or tantalum-doped tungsten are independently profiled with three different SIMS instruments. Their deuterium concentration profiles are compared showing good agreement. In order to assess the validity of the method, the integrated deuterium concentrations in the coatings given by one of the SIMS devices is compared with nuclear reaction analysis (NRA) data. Although in the case of tungsten the agreement between NRA and SIMS is satisfactory, for tantalum-doped tungsten samples the discrepancy is significant because of matrix effect induced by tantalum and differently eroded surface (W + Ta always exposed to plasma, W largely shadowed). A further comparison where the SIMS deuterium concentration is obtained by calibrating the measurements against NRA values is also presented. For the tungsten samples, where no Ta induced matrix effects are present, the two methods are almost equivalent.The results presented show the potential of the method provided that the standards used for the calibration reproduce faithfully the matrix nature of the samples.

  5. Atmospheric profiling via satellite to satellite occultations near water and ozone absorption lines for weather and climate

    NASA Astrophysics Data System (ADS)

    Kursinski, E. R.; Ward, D.; Otarola, A. C.; McGhee, J.; Stovern, M.; Sammler, K.; Reed, H.; Erickson, D.; McCormick, C.; Griggs, E.

    2016-05-01

    Significantly reducing weather and climate prediction uncertainty requires global observations with substantially higher information content than present observations provide. While GPS occultations have provided a major advance, GPS observations of the atmosphere are limited by wavelengths chosen specifically to minimize interaction with the atmosphere. Significantly more information can be obtained via satellite to satellite occultations made at wavelengths chosen specifically to characterize the atmosphere. Here we describe such a system that will probe cm- and mmwavelength water vapor absorption lines called the Active Temperature, Ozone and Moisture Microwave Spectrometer (ATOMMS). Profiling both the speed and absorption of light enables ATOMMS to profile temperature, pressure and humidity simultaneously, which GPS occultations cannot do, as well as profile clouds and turbulence. We summarize the ATOMMS concept and its theoretical performance. We describe field measurements made with a prototype ATOMMS instrument and several important capabilities demonstrated with those ground based measurements including retrieving temporal variations in path-averaged water vapor to 1%, in clear, cloudy and rainy conditions, up to optical depths of 17, remotely sensing turbulence and determining rain rates. We conclude with a vision of a future ATOMMS low Earth orbiting satellite constellation designed to take advantage of synergies between observational needs for weather and climate, ATOMMS unprecedented orbital remote sensing capabilities and recent cubesat technological innovations that enable a constellation of dozens of very small spacecraft to achieve many critical, but as yet unfulfilled, monitoring and forecasting needs.

  6. Spectroscopic determination of leaf biochemistry using band-depth analysis of absorption features and stepwise multiple linear regression

    USGS Publications Warehouse

    Kokaly, R.F.; Clark, R.N.

    1999-01-01

    We develop a new method for estimating the biochemistry of plant material using spectroscopy. Normalized band depths calculated from the continuum-removed reflectance spectra of dried and ground leaves were used to estimate their concentrations of nitrogen, lignin, and cellulose. Stepwise multiple linear regression was used to select wavelengths in the broad absorption features centered at 1.73 ??m, 2.10 ??m, and 2.30 ??m that were highly correlated with the chemistry of samples from eastern U.S. forests. Band depths of absorption features at these wavelengths were found to also be highly correlated with the chemistry of four other sites. A subset of data from the eastern U.S. forest sites was used to derive linear equations that were applied to the remaining data to successfully estimate their nitrogen, lignin, and cellulose concentrations. Correlations were highest for nitrogen (R2 from 0.75 to 0.94). The consistent results indicate the possibility of establishing a single equation capable of estimating the chemical concentrations in a wide variety of species from the reflectance spectra of dried leaves. The extension of this method to remote sensing was investigated. The effects of leaf water content, sensor signal-to-noise and bandpass, atmospheric effects, and background soil exposure were examined. Leaf water was found to be the greatest challenge to extending this empirical method to the analysis of fresh whole leaves and complete vegetation canopies. The influence of leaf water on reflectance spectra must be removed to within 10%. Other effects were reduced by continuum removal and normalization of band depths. If the effects of leaf water can be compensated for, it might be possible to extend this method to remote sensing data acquired by imaging spectrometers to give estimates of nitrogen, lignin, and cellulose concentrations over large areas for use in ecosystem studies.We develop a new method for estimating the biochemistry of plant material using

  7. Energy absorption buildup factors of human organs and tissues at energies and penetration depths relevant for radiotherapy and diagnostics.

    PubMed

    Manohara, S R; Hanagodimath, S M; Gerward, L

    2011-01-01

    Energy absorption geometric progression (GP) fitting parameters and the corresponding buildup factors have been computed for human organs and tissues, such as adipose tissue, blood (whole), cortical bone, brain (grey/white matter), breast tissue, eye lens, lung tissue, skeletal muscle, ovary, testis, soft tissue, and soft tissue (4-component), for the photon energy range 0.015-15 MeV and for penetration depths up to 40 mfp (mean free path). The chemical composition of human organs and tissues is seen to influence the energy absorption buildup factors. It is also found that the buildup factor of human organs and tissues changes significantly with the change of incident photon energy and effective atomic number, Z(eff). These changes are due to the dominance of different photon interaction processes in different energy regions and different chemical compositions of human organs and tissues. With the proper knowledge of buildup factors of human organs and tissues, energy absorption in the human body can be carefully controlled. The present results will help in estimating safe dose levels for radiotherapy patients and also useful in diagnostics and dosimetry. The tissue-equivalent materials for skeletal muscle, adipose tissue, cortical bone, and lung tissue are also discussed. It is observed that water and MS20 are good tissue equivalent materials for skeletal muscle in the extended energy range. PMID:22089011

  8. Depth-discrete Geochemical Profiling in Groundwater Using an Innovative In Situ Approach

    NASA Astrophysics Data System (ADS)

    Levison, J.; MacDonald, G.

    2014-12-01

    The presence of nitrate in groundwater is often associated with agricultural activity. Leaching below the root zone to aquifers from agricultural areas is a critical problem in many jurisdictions where concentrations are above drinking water guidelines. Traditionally, nitrate and other water quality parameters are collected using purge and sample techniques. Often this "snapshot" data both disrupts the natural subsurface flow system and is not detailed enough to determine critical water quality or quantity conditions. In this study, depth-discrete, continuous and in situ monitoring techniques are developed. While nitrate is the focus, parameters including temperature, dissolved oxygen (DO), turbidity, redox potential (ORP) and electrical conductivity (EC), are also monitored. Research sites examine a range of hydrogeological conditions from supply wells located in shallow, unconfined sandy aquifers (Norfolk County, Ontario, Canada) to fractured sedimentary bedrock aquifers (Guelph, Ontario) impacted by agricultural activity. The innovative groundwater quality sampling method uses the Submersible Ultraviolet Nitrate Analyzer (SUNATM) as well as the robust YSI EXO2 Water Quality SondeTM. Depth-discrete well profiling is used to evaluate vertical stratification of nitrate and field parameters along the entire borehole with a focus on the screened interval. The high resolution datasets show zones of changing water quality corresponding to different formations. In open bedrock boreholes in Guelph, distinct intervals were identified at different depths for pH, EC, DO and ORP. In the shallower wells in Norfolk County, increases in DO and EC along the screened interval suggest the presence of fresh groundwater representative of the aquifer, with potential implications for in situ long-term monitoring of groundwater parameters. Detailed profiles of DO and ORP at both sites can be combined with nitrate profile data to determine potential zones of denitrification. Water

  9. Depth profiling sulphur in bulk CdTe and {CdTe}/{CdS} thin film heterojunctions

    NASA Astrophysics Data System (ADS)

    Lane, D. W.; Conibeer, G. J.; Romani, S.; Healy, M. J. F.; Rogers, K. D.

    1998-03-01

    Polycrystalline CdTeCdS heterojunction solar cells are a possible candidate for the low cost, high efficiency conversion of solar energy. The formation of an intermediate CdS xTe 1- x layer during a high temperature annealing stage is believed to increase optical absorption and decrease cell efficiency. S diffusion in single crystal CdTe has been investigated by NRA using the 32S (d,p o) 33S nuclear reaction, at a deuteron energy of 2 MeV. Details of the NRA depth profiling procedure are given, which was found to be relatively straightforward and suitable for use on a small Van de Graaff accelerator. The resulting diffusion parameters are compared to those obtained by SIMS using a Cs + primary ion beam, examining negative secondary ions. The diffusion coefficients were found to be 1.1 × 10 -15cm 2 s -1 at 450°C and ˜8 × 10 -15cm -1 s at 550°C. S diffusion in thin films was also investigated by 2 MeV 4He + RBS on annealed polycrystalline CdSCdTe multilayers.

  10. Development of an ion time-of-flight spectrometer for neutron depth profiling

    NASA Astrophysics Data System (ADS)

    Cetiner, Mustafa Sacit

    Ion time-of-flight spectrometry techniques are investigated for applicability to neutron depth profiling. Time-of-flight techniques are used extensively in a wide range of scientific and technological applications including energy and mass spectroscopy. Neutron depth profiling is a near-surface analysis technique that gives concentration distribution versus depth for certain technologically important light elements. The technique uses thermal or sub-thermal neutrons to initiate (n, p) or (n, alpha) reactions. Concentration versus depth distribution is obtained by the transformation of the energy spectrum into depth distribution by using stopping force tables of the projectiles in the substrate, and by converting the number of counts into concentration using a standard sample of known dose value. Conventionally, neutron depth profiling measurements are based on charged particle spectrometry, which employs semiconductor detectors such as a surface barrier detector (SBD) and the associated electronics. Measurements with semiconductor detectors are affected by a number of broadening mechanisms, which result from the interactions between the projectile ion and the detector material as well as fluctuations in the signal generation process. These are inherent features of the detection mechanism that involve the semiconductor detectors and cannot be avoided. Ion time-of-flight spectrometry offers highly precise measurement capabilities, particularly for slow particles. For high-energy low-mass particles, measurement resolution tends to degrade with all other parameters fixed. The threshold for more precise ion energy measurements with respect to conventional techniques, such as direct energy measurement by a surface barrier detector, is directly related to the design and operating parameters of the device. Time-of-flight spectrometry involves correlated detection of two signals by a coincidence unit. In ion time-of-flight spectroscopy, the ion generates the primary input

  11. Depth profiling of 4-acetamindophenol-doped poly(lactic acid) films using cluster secondary ion mass spectrometry.

    PubMed

    Mahoney, Christine M; Roberson, Sonya V; Gillen, Greg

    2004-06-01

    The feasibility of using cluster secondary ion mass spectrometry for depth profiling of drug delivery systems is explored. The behavior of various biodegradable polymer films under dynamic SF(5)(+) primary ion bombardment was investigated, including several films doped with model drugs. The SF(5)(+) depth profiles obtained from these biodegradable polymer films showed very little degradation in secondary ion signal as a function of increasing primary ion dose, and it was discovered that the characteristic ion signals for the polymers remained constant for ion doses up to approximately 5 x 10(15) ions/cm(2). These results suggest that the polyester structure of the biodegradable polymers studied here allows for a greater ability to depth profile due to ease of main chain scission. Attempts were also made to depth profile through a series of poly(lactic acid) (PLA) films containing varying concentrations of the drug 4-acetamidophenol. The depth profiles obtained from these films show very little decrease in both the 4-acetamidophenol molecular ion and PLA fragment ion signals as a function of increasing SF(5)(+) primary ion dose. Similar results were obtained with theophylline-doped PLA films. These results show that, in some drug delivery devices, it is possible to monitor the distribution of a drug as a function of depth by using cluster primary ion beams. PMID:15167802

  12. C and N depth profiles of SiCN layers determined with nuclear reaction analyses and AES

    NASA Astrophysics Data System (ADS)

    Link, F.; Baumann, H.; Bethge, K.; Klewe-Nebenius, H.; Bruns, M.

    1998-04-01

    Si 1C xN y layers were prepared by sequential implantation of 40 keV 13C- and 50 keV 15N-ions into c-Si <1 1 1> samples near RT. The carbon and nitrogen depth distributions were measured using the resonant nuclear (p,γ) reactions 15N(p,αγ) 12C at Eres=429 keV and 13C(p,γ) 14N at Eres=1748 keV, respectively. The measured raw data of depth profiling (gamma yield versus the proton beam energy) are converted to concentration-depth profiles of the elements C, N and Si with a common depth scale by using a new developed computer algorithm. These concentration profiles are compared with those obtained with Auger Electron Spectroscopy (AES) and non-Rutherford Backscattering Spectrometry (n-RBS).

  13. Characterization of the noise in secondary ion mass spectrometry depth profiles

    SciTech Connect

    Chu, D.P.; Dowsett, M.G.; Cooke, G.A.

    1996-12-01

    The noise in the depth profiles of secondary ion mass spectrometry (SIMS) is studied using different samples under various experimental conditions. Despite the noise contributions from various parts of the dynamic SIMS process, its overall character agrees very well with the Poissonian rather than the Gaussian distribution in all circumstances. The Poissonian relation between the measured mean-square error and mean can be used to describe our data in the range of four orders. The departure from this relation at high counts is analyzed and found to be due to the saturation of the channeltron used. Once saturated, the detector was found to exhibit hysteresis between rising and falling input flux and output counts. {copyright} {ital 1996 American Institute of Physics.}

  14. Comparative erosion yields, topographical changes and depth profile analysis of ion eroded nickel-based alloys

    NASA Astrophysics Data System (ADS)

    Navinšek, B.; Panjan, P.; Peternel, M.; Žabkar, A.

    1982-03-01

    Polished polycrystalline alloy targets of Inconel 600, Inconel 625 and Nimonic alloy PE 16 were bombarded with 10 keV He + and A + ions at normal incidence and at room temperature. Comparative studies of the ion erosion yield, as measured by step-height measurements, were made. The correlation between the observed topography and the changes in surface composition and depth profile was studied on irradiated samples by AES. Additionally, total sputtering yields were measured on sputtered films of these materials using a quartz crystal microbalance. The results showed that ion erosion yields are different for the three materials studied, while sputtering yields were similar for He + ions and different for A + ions. A non-linear effect was observed for low dose yields when ion dose and fluence dependence was studied. The topography of ion irradiated nickel-based alloys is specific for a chosen metallographic treatment, determining the bulk and surface structure of the target material.

  15. Auger electron spectroscopy and depth profile study of oxidation of modified 440C steel

    NASA Technical Reports Server (NTRS)

    Ferrante, J.

    1974-01-01

    Auger electron spectroscopy (AES) and sputtering were used to study selective oxidation of modified 440C steel. The sample was polycrystalline. Oxidation was performed on initially clean surfaces for pressures ranging from 1 x 10 to the minus 7th power to 1 x 10 to the minus 5th power torr and temperatures ranging from room temperature to 800 C. AES traces were taken during oxidation. In situ sputtering depth profiles are also obtained. A transition temperature is observed in the range 600 to 700 C for which the composition of the outer surface oxide changed from iron oxide to chromium oxide. Heating in vacuum about 5 x 10 to the minus 10 power torr to 700 C causes conversion of the iron oxide surface to chromium oxide.

  16. Application of resonant laser postionization SNMS for quantitative depth profiling in stainless steel with oxide film

    NASA Astrophysics Data System (ADS)

    Kubota, N.; Hayashi, S.

    2008-12-01

    A resonance laser postionization secondary neutral mass spectroscopy (SNMS) system with a quadrupole mass spectrometer has been developed to investigate its fundamental process for quantitative analysis of metal alloys and compounds. The feature of our SNMS system is to bombard ions with low energy incidence. The energy dependence of Cr/Fe ratios and resonant enhanced multi-photon ionization spectra of Fe in three kinds of samples have been observed. These results indicate that the existence of oxygen may disturb the quantitative measurement due to the population change of a sputtered atom though oxygen irradiation could prevent selective sputtering and ion enhanced sub-surface redistribution in stainless steel. The measured depth profiles of Cr, Fe and Ni in the colored stainless steel have been in agreement with the reference values within a factor of about 2.

  17. Scanning Electron Microscopy Investigation of a Sample Depth Profile Through the Martian Meteorite Nakhla

    NASA Technical Reports Server (NTRS)

    Toporski, Jan; Steele, Andrew; Westall, Frances; McKay, David S.

    2000-01-01

    The ongoing scientific debate as to whether or not the Martian meteorite ALH84001 contained evidence of possible biogenic activities showed the need to establish consistent methods to ascertain the origin of such evidence. To distinguish between terrestrial organic material/microbial contaminants and possible indigenous microbiota within meteorites is therefore crucial. With this in mind a depth profile consisting of four samples from a new sample allocation of Martian meteorite Nakhla was investigated using scanning electron microscopy (SEM) and energy dispersive X-ray analysis. SEM imaging of freshly broken fractured chips revealed structures strongly recent terrestrial microorganisms, in some cases showing evidence of active growth. This conclusion was supported by EDX analysis, which showed the presence of carbon associated with these structures, we concluded that these structures represent recent terrestrial contaminants rather than structures indigenous to the meteorite. Page

  18. Properties of depth-profile controlled boron nitride films prepared by ion-beam assisted deposition

    NASA Astrophysics Data System (ADS)

    Kumagai, M.; Suzuki, M.; Suzuki, T.; Tanaka, Y.; Setsuhara, Y.; Miyake, S.; Ogata, K.; Kohata, M.; Higeta, K.; Einishi, T.; Suzuki, Y.; Shimoitani, Y.; Motonami, Y.

    1997-05-01

    Boron nitride films were prepared by vapor deposition of boron and simultaneous bombardment with mixed gas ions of nitrogen and argon in the energy range of 0.2 to 20 keV. The films were prepared on various kinds of substrates including silicon wafers, tungsten carbide plates and various ceramic plates at a temperature of 400°C. In the synthesis of the BN films, a boron-rich buffer layer between the substrate and the BN film was formed by energetic nitrogen ion beam bombardment, improving tribological properties such as the depth-profile controlled layer. The buffer layer improved film adhesion, and chemical stability, thermal stability at elevated temperature and corrosion resistance of the BN films also gave good results.

  19. Depth profiles of MeV heavy ions implanted into Si and lithium triborate

    NASA Astrophysics Data System (ADS)

    Wang, Ke-Ming; Shi, Bo-Rong; Cue, Nelson; Shen, Ding-Yu; Chen, Feng; Wang, Xue-Lin; Lu, Fei

    2004-10-01

    MeV Cu + and Ni + ions were implanted into Si crystal and lithium triborate. The depth profiles of implanted Cu + and Ni + ions into Si and lithium triborate were measured by secondary ion mass spectrometry (SIMS). Mean projected range and range straggling extracted are compared with calculated values based on different versions of transport of ions in matter: TRIM'90, TRIM'98 and SRIM 2003. The results show that TRIM'90 has predicted well the experimental data of mean projected range and range straggling for MeV Cu + ions implanted into Si, the maximum differences between measured and calculated values are within 4%, but for the case of 2.0 MeV Ni + ions implanted into lithium triborate, the experimental value is significantly different from the calculated one based on TRIM'90.

  20. Depth profiling analysis of solar wind helium collected in diamond-like carbon film from Genesis

    SciTech Connect

    Bajo, Ken-ichi; Olinger, Chad T.; Jurewicz, Amy J.G.; Burnett, Donald S.; Sakaguchi, Isao; Suzuki, Taku; Itose, Satoru; Ishihara, Morio; Uchino, Kiichiro; Wieler, Rainer; Yurimoto, Hisayoshi

    2015-10-01

    The distribution of solar-wind ions in Genesis mission collectors, as determined by depth profiling analysis, constrains the physics of ion solid interactions involving the solar wind. Thus, they provide an experimental basis for revealing ancient solar activities represented by solar-wind implants in natural samples. We measured the first depth profile of ⁴He in a collector; the shallow implantation (peaking at <20 nm) required us to use sputtered neutral mass spectrometry with post-photoionization by a strong field. The solar wind He fluence calculated using depth profiling is ~8.5 x 10¹⁴ cm⁻². The shape of the solar wind ⁴He depth profile is consistent with TRIM simulations using the observed ⁴He velocity distribution during the Genesis mission. It is therefore likely that all solar-wind elements heavier than H are completely intact in this Genesis collector and, consequently, the solar particle energy distributions for each element can be calculated from their depth profiles. Ancient solar activities and space weathering of solar system objects could be quantitatively reproduced by solar particle implantation profiles.

  1. Measuring Compositions in Organic Depth Profiling: Results from a VAMAS Interlaboratory Study.

    PubMed

    Shard, Alexander G; Havelund, Rasmus; Spencer, Steve J; Gilmore, Ian S; Alexander, Morgan R; Angerer, Tina B; Aoyagi, Satoka; Barnes, Jean-Paul; Benayad, Anass; Bernasik, Andrzej; Ceccone, Giacomo; Counsell, Jonathan D P; Deeks, Christopher; Fletcher, John S; Graham, Daniel J; Heuser, Christian; Lee, Tae Geol; Marie, Camille; Marzec, Mateusz M; Mishra, Gautam; Rading, Derk; Renault, Olivier; Scurr, David J; Shon, Hyun Kyong; Spampinato, Valentina; Tian, Hua; Wang, Fuyi; Winograd, Nicholas; Wu, Kui; Wucher, Andreas; Zhou, Yufan; Zhu, Zihua; Cristaudo, Vanina; Poleunis, Claude

    2015-08-20

    We report the results of a VAMAS (Versailles Project on Advanced Materials and Standards) interlaboratory study on the measurement of composition in organic depth profiling. Layered samples with known binary compositions of Irganox 1010 and either Irganox 1098 or Fmoc-pentafluoro-l-phenylalanine in each layer were manufactured in a single batch and distributed to more than 20 participating laboratories. The samples were analyzed using argon cluster ion sputtering and either X-ray photoelectron spectroscopy (XPS) or time-of-flight secondary ion mass spectrometry (ToF-SIMS) to generate depth profiles. Participants were asked to estimate the volume fractions in two of the layers and were provided with the compositions of all other layers. Participants using XPS provided volume fractions within 0.03 of the nominal values. Participants using ToF-SIMS either made no attempt, or used various methods that gave results ranging in error from 0.02 to over 0.10 in volume fraction, the latter representing a 50% relative error for a nominal volume fraction of 0.2. Error was predominantly caused by inadequacy in the ability to compensate for primary ion intensity variations and the matrix effect in SIMS. Matrix effects in these materials appear to be more pronounced as the number of atoms in both the primary analytical ion and the secondary ion increase. Using the participants' data we show that organic SIMS matrix effects can be measured and are remarkably consistent between instruments. We provide recommendations for identifying and compensating for matrix effects. Finally, we demonstrate, using a simple normalization method, that virtually all ToF-SIMS participants could have obtained estimates of volume fraction that were at least as accurate and consistent as XPS. PMID:26204428

  2. Small scale temporal distribution of radiocesium in undisturbed coniferous forest soil: Radiocesium depth distribution profiles.

    PubMed

    Teramage, Mengistu T; Onda, Yuichi; Kato, Hiroaki

    2016-04-01

    The depth distribution of pre-Fukushima and Fukushima-derived (137)Cs in undisturbed coniferous forest soil was investigated at four sampling dates from nine months to 18 months after the Fukushima nuclear power plant accident. The migration rate and short-term temporal variability among the sampling profiles were evaluated. Taking the time elapsed since the peak deposition of pre-Fukushima (137)Cs and the median depth of the peaks, its downward displacement rates ranged from 0.15 to 0.67 mm yr(-1) with a mean of 0.46 ± 0.25 mm yr(-1). On the other hand, in each examined profile considerable amount of the Fukushima-derived (137)Cs was found in the organic layer (51%-92%). At this moment, the effect of time-distance on the downward distribution of Fukushima-derived (137)Cs seems invisible as its large portion is still found in layers where organic matter is maximal. This indicates that organic matter seems the primary and preferential sorbent of radiocesium that could be associated with the physical blockage of the exchanging sites by organic-rich dusts that act as a buffer against downward propagation of radiocesium, implying radiocesium to be remained in the root zone for considerable time period. As a result, this soil section can be a potential source of radiation dose largely due to high radiocesium concentration coupled with its low density. Generally, such kind of information will be useful to establish a dynamic safety-focused decision support system to ease and assist management actions. PMID:26803260

  3. Measuring Compositions in Organic Depth Profiling: Results from a VAMAS Interlaboratory Study

    SciTech Connect

    Shard, A. G.; Havelund, Rasmus; Spencer, Steve J.; Gilmore, I. S.; Alexander, Morgan R.; Angerer, Tina B.; Aoyagi, Satoka; Barnes, Jean P.; Benayad, Anass; Bernasik, Andrzej; Ceccone, Giacomo; Counsell, Jonathan D.; Deeks, Christopher; Fletcher, John S.; Graham, Daniel J.; Heuser, Christian; Lee, Tae G.; Marie, Camille; Marzec, Mateusz M.; Mishra, Gautam; Rading, Derk; Renault, Oliver; Scurr, David J.; Shon, Hyun K.; Spampinato, Valentina; Tian, Hua; Wang, Fuyi; Winograd, Nicholas; Wu, Kui; Wucher, Andreas; Zhou, Yufan; Zhu, Zihua

    2015-07-23

    We report the results of a VAMAS (Versailles Project on Advanced Materials and Standards) interlaboratory study on the measurement of composition in organic depth profiling. Layered samples with known binary compositions of Irganox 1010 and either Irganox 1098 or Fmoc-pentafluoro-L-phenylalanine in each layer were manufactured in a single batch and distributed to more than 20 participating laboratories. The samples were analyzed using argon cluster ion sputtering and either X-ray Photoelectron Spectroscopy (XPS) or Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) to generate depth profiles. Participants were asked to estimate the volume fractions in two of the layers and were provided with the compositions of all other layers. Participants using XPS provided volume fractions within 0.03 of the nominal values. Participants using ToF-SIMS either made no attempt, or used various methods that gave results ranging in error from 0.02 to over 0.10 in volume fraction, the latter representing a 50% relative error for a nominal volume fraction of 0.2. Error was predominantly caused by inadequacy in the ability to compensate for primary ion intensity variations and the matrix effect in SIMS. Matrix effects in these materials appear to be more pronounced as the number of atoms in both the primary analytical ion and the secondary ion increase. Using the participants’ data we show that organic SIMS matrix effects can be measured and are remarkably consistent between instruments. We provide recommendations for identifying and compensating for matrix effects. Finally we demonstrate, using a simple normalization method, that virtually all ToF-SIMS participants could have obtained estimates of volume fraction that were at least as accurate and consistent as XPS.

  4. Cathodoluminescence and depth profiling studies of unintentionally doped GaN films grown by MOVPE

    NASA Astrophysics Data System (ADS)

    Tounsi, Nabil; Guermazi, Hajer; Guermazi, Samir; El Jani, Belgacem

    2015-10-01

    GaN layers are grown by metalorganic vapor phase epitaxy at 1050 °C on porous silicon and (111) oriented silicon substrates. AlN buffer layers of about 100 nm thickness were previously deposited on Si substrates. The effect of substrates on optical properties is revealed by Cathodoluminescence measurements (CL), recorded at room temperature and liquid nitrogen temperature. Various excitonic transitions are depicted. Spectral features associated with F°X energy around 3.4 eV and bound excitons (D°X and A°X in the range 3.29-3.35 eV) related to wurtzite GaN excitons are observed. Yellow band is located around 2.15 eV. CL depth profiling is also investigated at various e-beam energies (3-25 keV). The low-energy electron beam irradiation reveals an inhomogeneous distribution of point defects in depth, and high non-radiative recombination beyond a threshold energy. Good agreement between our experimental data and literature is obtained. Moreover, CL investigations prove that growth of GaN on (111) oriented Si substrate improve the crystalline quality of the layer.

  5. Extremely eroded or incredibly young - 10Be depth profile dating of moraines in the Swiss Midlands

    NASA Astrophysics Data System (ADS)

    Wüthrich, Lorenz; Zech, Roland; Haghipour, Negar; Gnägi, Christian; Christl, Markus; Ivy-Ochs, Susan; Veit, Heinz

    2014-05-01

    During the Pleistocene, glaciers advanced repeatedly from the Alps into the Swiss Midlands. The exact extent and timing are still under debate, even for the last glacial advances. Decalcification depths, for example, increase from west to east in the western Swiss Midlands and have been interpreted to indicate that the Valais (Rhone) glacier may have been less extensive during the global Last Glacial Maximum (LGM) at 20 ka than assumed so far [1]. In an attempt to provide more quantitative age control, we applied 10Be depth profile dating [2] on moraines at two locations. Steinhof has previously been dated to the global LGM based on exposure ages from four boulders [3], and Niederbuchsiten presumably lies outside the last glacial ice extent [1]. The 10Be concentrations at both sites decrease consistently with depth, but are very similar. Assuming only a few decimeters of erosion since moraine deposition, we obtain apparent exposure ages of ~20 ka. Niederbuchsiten would thus be unexpectedly young, implying a much more extensive extent of the LGM glacier than assumed so far. Alternatively, if the till at Niederbuchsiten was deposited during or before the penultimate glaciation (>130 ka), the surprisingly low 10Be concentrations indicate several meters of erosion during the last glacial cycle and/or the Holocene, which seems to be at odds with the deep and intensive soil formation. References: [1] Bitterli et al. (2011) Geologischer Atlas der Schweiz, Blatt 1108. [2] Hidy et al. (2010) Geochem. Geophys. Geosyst. 11, doi:10.1029/2010GC003084. [3] Ivy- Ochs et al. (2004) Ecl. Geol. Helv. 97, 47-55.

  6. Mixed layer depth and chlorophyll a: Profiling float observations in the Kuroshio-Oyashio Extension region

    NASA Astrophysics Data System (ADS)

    Itoh, Sachihiko; Yasuda, Ichiro; Saito, Hiroaki; Tsuda, Atsushi; Komatsu, Kosei

    2015-11-01

    Variability in the chlorophyll a concentration (Chl) in relation to fluctuations in the mixed layer (ML) was investigated together with turbidity (Tur) in the Kuroshio-Oyashio Extension region, using profiling floats. A particular focus was the validity of two hypotheses concerning the spring bloom: the critical depth hypothesis (CDH) and the recently proposed alternative, the disturbance-recovery hypothesis (DRH). During the period from winter to early spring, Chl and Tur integrated over the photosynthetically active layer (PL; defined as the greatest depth of the ML and the euphotic layer) increased with increasing PL depth (PLD), indicating an increase in the phytoplankton biomass. This result is partly consistent with the DRH in that the observed increase in biomass was not explained by an increase in production. Instead, it was more likely attributable to a reduction in the loss rate. However, theoretical analyses revealed that grazer dilution alone could not cause this increase in biomass because such an increase in the ML in the real ocean (as opposed to a dilution experiment within a bottle) would cause a reduction in the mean light intensity. Despite the loss-controlled fluctuation in biomass during the period of low light, a production-driven fluctuation in biomass was also revealed. This occurred when the light intensity was elevated, particularly after late spring, and was consistent with the CDH. Thus, the present study suggests that both the production-driven and loss-driven hypotheses are responsible for the dynamics of the phytoplankton dynamics from winter to spring in the Kuroshio-Oyashio Extension region.

  7. Historical Tracking of Nitrate in Contrasting Vineyard Using Water Isotopes and Nitrate Depth Profiles

    NASA Astrophysics Data System (ADS)

    Sprenger, M.; Erhardt, M.; Riedel, M.; Weiler, M.

    2015-12-01

    The European Water Framework Directive (EWFD) aims to achieve a good chemical status for the groundwater bodies in Europe by the year 2015. Despite the effort to reduce the nitrate pollution from agriculture within the last two decades, there are still many groundwater aquifers that exceed nitrate concentrations above the EWFD threshold of 50 mg/l. Viticulture is seen as a major contributor of nitrate leaching and sowing of a green cover was shown to have a positive effect on lowering the nitrate loads in the upper 90 cm of the soil. However, the consequences for nitrate leaching into the subsoil were not yet tested. We analyzed the nitrate concentrations and pore water stable isotope composition to a depth of 380 cm in soil profiles under an old vineyard and a young vineyard with either soil tillage or permanent green cover in between the grapevines. The pore water stable isotopes were used to calibrate a soil physical model, which was then used to infer the age of the soil water at different depths. This way, we could relate elevated nitrate concentrations below an old vineyard to tillage processes that took place during the winter two years before the sampling. We further showed that the elevated nitrate concentration in the subsoil of a young vineyard can be related to the soil tillage prior to the planting of the new vineyard. If the soil is kept bare due to tillage, a nitrate concentration of 200 kg NO3--N/ha is found in 290 to 380 cm depth 2.5 years after the installation of the vineyard. The amount of nitrate leaching is considerably reduced due to a seeded green cover between the grapevines that takes up a high share of the mobilized nitrate reducing a potential contamination of the groundwater.

  8. [Effect of fertilization depth on 15N-urea absorption, utilization and loss in dwarf apple trees].

    PubMed

    Ding, Ning; Chen, Qian; Xu, Hai-gang; Ji, Meng-meng; Jiang, Han; Jiang, Yuan-mao

    2015-03-01

    Five-year-old 'Fuji'3/M26/M. hupehensis Rehd. seedlings were treated by 15N tracer to study the effects of fertilization depth (0, 20 and 40 cm) on 15N-urea absorption, distribution, utilization and loss in soil. The results showed that the plant leaf area, chlorophyll content and total N of apple leaves in 20 cm treatment were obviously higher than 0 cm and 40 cm treatments. The 15N derived from fertilizer (Ndff) in different organs of apple plant under different depths were significantly different, and the Ndff was the highest in roots at the full-bloom stage, and then in perennial branches. During the shoot rapid-growing and flower bud differentiation stage, the Ndff of new organs higher than that of the storage organs, and the Ndff of different organs were high level at fruit rapid-expanding stage, and the Ndff of fruit was the highest. The distribution ratio of 15N at fruit maturity stage was significantly different under fertilization depths, and that of the vegetative and repro- ductive organs of 20 cm treatment were obviously higher than 0 cm and 40 cm treatments, but that of the storage organs of 20 cm treatment was lower than 0 cm and 40 cm treatments. At fruit maturity stage, 15N utilization rate of apple plant of 20 cm treatment was 24.0%, which was obviously higher than 0 cm (14.1%) and 40 cm (7.6%) treatments, and 15N loss rate was 54.0%, which was obviously lower than 0 cm (67.8%) and 40 cm (63.5%) treatments. With the increase of fertilization depths, the N residue in soil increased sharply. PMID:26211056

  9. Thermal depth profiling of vascular lesions: automated regularization of reconstruction algorithms

    PubMed Central

    Verkruysse, Wim; Choi, Bernard; Zhang, Jenny R; Kim, Jeehyun; Nelson, J Stuart

    2008-01-01

    Pulsed photo-thermal radiometry (PPTR) is a non-invasive, non-contact diagnostic technique used to locate cutaneous chromophores such as melanin (epidermis) and hemoglobin (vascular structures). Clinical utility of PPTR is limited because it typically requires trained user intervention to regularize the inversion solution. Herein, the feasibility of automated regularization was studied. A second objective of this study was to depart from modeling port wine stain PWS, a vascular skin lesion frequently studied with PPTR, as strictly layered structures since this may influence conclusions regarding PPTR reconstruction quality. Average blood vessel depths, diameters and densities derived from histology of 30 PWS patients were used to generate 15 randomized lesion geometries for which we simulated PPTR signals. Reconstruction accuracy for subjective regularization was compared with that for automated regularization methods. The objective regularization approach performed better. However, the average difference was much smaller than the variation between the 15 simulated profiles. Reconstruction quality depended more on the actual profile to be reconstructed than on the reconstruction algorithm or regularization method. Similar, or better, accuracy reconstructions can be achieved with an automated regularization procedure which enhances prospects for user friendly implementation of PPTR to optimize laser therapy on an individual patient basis. PMID:18296773

  10. Wind-Speed Profile and Roughness Sublayer Depth Modelling in Urban Boundary Layers

    NASA Astrophysics Data System (ADS)

    Pelliccioni, Armando; Monti, Paolo; Leuzzi, Giovanni

    2016-03-01

    We propose a new formulation for the wind-speed profile in the urban boundary layer, which can be viewed as a generalisation of the commonly used logarithmic law. The model is based on the assumption that the role played by the classical aerodynamic roughness length and the displacement height in the logarithmic law is taken by a sole variable, the local length scale, which follows a pattern of exponential decrease with height. Starting from wind-speed profiles collected at Villa Pamphili park, Rome, Italy, an empirical fit is used to determine the model parameters. The results show that the local length scale depends also on the friction velocity and that, with appropriate normalization, it reduces to a family of curves that spreads according to the planar area fraction. Another novel aspect is the estimation of the roughness sublayer depth, which can be expressed as a function of the friction velocity and morphometric quantities such as the building height and the planar area fraction. It is also found that the rate of growth with height of the Prandtl mixing length linked to the new formulation is, just above the canopy, lower than the canonical value 0.41, and approaches the latter value well above the roughness sublayer. The model performance is tested by comparison with laboratory and field data reported in the literature.

  11. Wind-Speed Profile and Roughness Sublayer Depth Modelling in Urban Boundary Layers

    NASA Astrophysics Data System (ADS)

    Pelliccioni, Armando; Monti, Paolo; Leuzzi, Giovanni

    2016-08-01

    We propose a new formulation for the wind-speed profile in the urban boundary layer, which can be viewed as a generalisation of the commonly used logarithmic law. The model is based on the assumption that the role played by the classical aerodynamic roughness length and the displacement height in the logarithmic law is taken by a sole variable, the local length scale, which follows a pattern of exponential decrease with height. Starting from wind-speed profiles collected at Villa Pamphili park, Rome, Italy, an empirical fit is used to determine the model parameters. The results show that the local length scale depends also on the friction velocity and that, with appropriate normalization, it reduces to a family of curves that spreads according to the planar area fraction. Another novel aspect is the estimation of the roughness sublayer depth, which can be expressed as a function of the friction velocity and morphometric quantities such as the building height and the planar area fraction. It is also found that the rate of growth with height of the Prandtl mixing length linked to the new formulation is, just above the canopy, lower than the canonical value 0.41, and approaches the latter value well above the roughness sublayer. The model performance is tested by comparison with laboratory and field data reported in the literature.

  12. Calculated and measured depth dose profiles in a phantom exposed to neutron radiation fields

    SciTech Connect

    Scherpelz, R.I.; Tanner, J.E.; Sigalla, L.A.; Hadlock, D.E.

    1989-05-01

    An accurate evaluation of doses caused by external sources of neutron radiation depends on knowledge of the transport of radiation inside the human body. Health physicists use two primary methods for studying this radiation transport: computer calculations and measurements. Both computer calculations and measurements were performed under well controlled, nearly identical conditions to determine the extent of their agreement. A comparison of the dose profiles predicted by both measurements and calculations was thus possible. The measurements were performed in a cylindrical phantom made of tissue equivalent plastic. The phantom size, 61 cm high and 30 cm in diameter, was chosen to approximate the human torso and to match the dimensions of cylindrical phantoms used by previous calculations. Holes were drilled down through the phantom to accommodate small tissue equivalent proportional counters (TEPCs) at various depths in the phantom. These counters were used to measure the neutron dose inside the phantom when it was exposed to various sources of neutrons. The holes in the phantom could also accommodate miniature Geiger-Mueller detectors to measure the gamma component of the dose. Neutron and gamma dose profiles were measured for two different sources of neutrons: an unmoderated /sup 252/Cf source and a 733-keV neutron beam generated by a Van de Graaff accelerator. 14 refs., 13 figs., 11 tabs.

  13. Constraining strength/depth profiles using laboratory experiments and field structural observations

    NASA Astrophysics Data System (ADS)

    Evans, B.

    2012-04-01

    Strength/depth profiles are often used as standard models to constrain treatments of lithosphere-scale geodynamics. Such profiles have virtue because they are motivated by our understanding of inelastic deformation of rocks, and because they can be used in complex numerical calculations. But, by attempting to construct simple, generic mechanical models, often while lacking detailed descriptions of the sub-surface, such treatments may ignore important issues, including spatial heterogeneities in rock composition, in strain displacements, or in other thermodynamic parameters, including temperature, fluid pressure and composition. Further, these profiles usually assume constitutive equations that reflect combinations of a simple yield criterion with steady-state creep. Thus, transient mechanical behavior is neglected. Fortunately, a plethora of recent laboratory, field structural, and computational studies may now be used to shed light on mechanical behavior at a much broader range of temperature, pressure, strain rates, and strain. For example, new experiments provide a description of creep in minerals at pressures greater than 2 GPa, of friction at seismic velocities, and of strains larger than 5. Observations of field microstructures, coupled with mechanical descriptions gleaned from laboratory experiments and theoretical treatments of the thermodynamics and mechanics of deformation, provide important insights into the way that localization occurs in natural shear zones. Finally, Earth scientists have gained an improved understanding of the subtle, yet important, interplay among fluids, transport properties, and rock deformation, which are capable of producing rich patterns of deformation. Among several important and challenging issues that need work is spatial scaling of properties; it is particularly important to consider differences in length scales that are embedded in the various techniques of field and global geophysics, field geology, and experiments. Our

  14. Will solid-state drives accelerate your bioinformatics? In-depth profiling, performance analysis and beyond.

    PubMed

    Lee, Sungmin; Min, Hyeyoung; Yoon, Sungroh

    2016-07-01

    A wide variety of large-scale data have been produced in bioinformatics. In response, the need for efficient handling of biomedical big data has been partly met by parallel computing. However, the time demand of many bioinformatics programs still remains high for large-scale practical uses because of factors that hinder acceleration by parallelization. Recently, new generations of storage devices have emerged, such as NAND flash-based solid-state drives (SSDs), and with the renewed interest in near-data processing, they are increasingly becoming acceleration methods that can accompany parallel processing. In certain cases, a simple drop-in replacement of hard disk drives by SSDs results in dramatic speedup. Despite the various advantages and continuous cost reduction of SSDs, there has been little review of SSD-based profiling and performance exploration of important but time-consuming bioinformatics programs. For an informative review, we perform in-depth profiling and analysis of 23 key bioinformatics programs using multiple types of devices. Based on the insight we obtain from this research, we further discuss issues related to design and optimize bioinformatics algorithms and pipelines to fully exploit SSDs. The programs we profile cover traditional and emerging areas of importance, such as alignment, assembly, mapping, expression analysis, variant calling and metagenomics. We explain how acceleration by parallelization can be combined with SSDs for improved performance and also how using SSDs can expedite important bioinformatics pipelines, such as variant calling by the Genome Analysis Toolkit and transcriptome analysis using RNA sequencing. We hope that this review can provide useful directions and tips to accompany future bioinformatics algorithm design procedures that properly consider new generations of powerful storage devices. PMID:26330577

  15. Depth and Shape of the 0.94-microm Water Vapor Absorption Band for Clear and Cloudy Skies.

    PubMed

    Volz, F E

    1969-11-01

    Sky radiation near zenith and solar radiation in the rhosigmatau band region were recorded by means of a rotating interference filter (lambda0.98-0.88 microm) and a silicon detector. Although the spectral resolution of the simple spectrometer was not high, the water vapor content of the cloud free atmosphere was obtained with reasonable accuracy. The band depth of the radiation from thin, bright clouds was only slightly greater than that of the cloud free atmosphere, but dense and dark clouds showed deep bands mainly caused by increased path length as a result of multiple scattering. Considerable distortion of the band due to absorption by liquid water is observed in the radiation from very dark and dense clouds, and sometimes during snowfall. Some laboratory measurements are also discussed. PMID:20076009

  16. Phenolic acids from wheat show different absorption profiles in plasma: a model experiment with catheterized pigs.

    PubMed

    Nørskov, Natalja P; Hedemann, Mette S; Theil, Peter K; Fomsgaard, Inge S; Laursen, Bente B; Knudsen, Knud Erik Bach

    2013-09-18

    The concentration and absorption of the nine phenolic acids of wheat were measured in a model experiment with catheterized pigs fed whole grain wheat and wheat aleurone diets. Six pigs in a repeated crossover design were fitted with catheters in the portal vein and mesenteric artery to study the absorption of phenolic acids. The difference between the artery and the vein for all phenolic acids was small, indicating that the release of phenolic acids in the large intestine was not sufficient to create a porto-arterial concentration difference. Although, the porto-arterial difference was small, their concentrations in the plasma and the absorption profiles differed between cinnamic and benzoic acid derivatives. Cinnamic acids derivatives such as ferulic acid and caffeic acid had maximum plasma concentration of 82 ± 20 and 200 ± 7 nM, respectively, and their absorption profiles differed depending on the diet consumed. Benzoic acid derivatives showed low concentration in the plasma (<30 nM) and in the diets. The exception was p-hydroxybenzoic acid, with a plasma concentration (4 ± 0.4 μM), much higher than the other plant phenolic acids, likely because it is an intermediate in the phenolic acid metabolism. It was concluded that plant phenolic acids undergo extensive interconversion in the colon and that their absorption profiles reflected their low bioavailability in the plant matrix. PMID:23971623

  17. What Can Radiocarbon Depth Profiles Tell Us About The LGM Circulation?

    NASA Astrophysics Data System (ADS)

    Burke, A.; Stewart, A.; Adkins, J. F.; Ferrari, R. M.; Thompson, A. F.; Jansen, M. F.

    2014-12-01

    Published reconstructions of radiocarbon in the Atlantic sector of the Southern Ocean indicate that there is a mid-depth maximum in radiocarbon age during the last glacial maximum (LGM). This is in contrast to the modern ocean where intense mixing between water masses along shared density surfaces (isopycnals) results in a relatively homogenous radiocarbon profile. A recent study (Ferrari et al. 2014) suggested that the extended Antarctic sea ice cover during the LGM necessitated a shallower boundary between the upper and lower branches of the meridional overturning circulation (MOC). This shoaled boundary lay above major topographic features and their associated strong diapycnal mixing, which isolated dense southern-sourced water in the lower branch of the overturning circulation. This isolation would have allowed radiocarbon to decay, and thus provides a possible explanation for the mid-depth radiocarbon age bulge. We test this hypothesis using an idealized, 2D, residual-mean dynamical model of the global overturning circulation. Concentration distributions of a decaying tracer that is advected by the simulated overturning are compared to published radiocarbon data. We test the sensitivity of the mid-depth radiocarbon age to changes in sea ice extent, wind strength, and isopycnal and diapycnal diffusion. The mid-depth radiocarbon age bulge is most likely caused by the different circulation geometry, associated with increased sea ice extent. In particular, with an LGM-like sea ice extent the upper and lower branches of the MOC no longer share isopycnals, so radiocarbon-rich northern-sourced water is no longer mixed rapidly into the southern-sourced water. However, this process alone cannot explain the magnitude of the glacial radiocarbon anomalies; additional isolation (e.g. from reduced air-sea gas exchange associated with the increased sea ice) is required. Ferrari, R., M. F. Jansen, J. F. Adkins, A. Burke, A. L. Stewart, and A. F. Thompson (2014), Antarctic sea

  18. Analysis for nonlinear inversion technique developed to estimate depth-distribution of absorption by spatially resolved backscattering measurement

    NASA Astrophysics Data System (ADS)

    Nishida, Kazuhiro; Namita, Takeshi; Kato, Yuji; Shimizu, Koichi

    2015-03-01

    We have proposed a new nonlinear inversion technique to estimate the spatial distribution of the absorption coefficient (μa) in the depth direction of a turbid medium by spatially resolved backscattering measurement. With this technique, we can obtain cross-sectional image of μa as deep as the backscattered light traveled even when the transmitted light through the medium cannot be detected. In this technique, the depth distribution of absorption coefficient is determined by iterative calculation using the spatial path-length distribution (SPD) of traveled photons as a function of source-detector distance. In this calculation, the variance of path-length of many photons in each layer is also required. The SPD and the variance of path-length are obtained by Monte Carlo simulation using a known reduced scattering coefficient (μs'). Therefore, we need to know the μs' of the turbid medium beforehand. We have shown in computer simulation that this technique works well when the μs' is the typical values of mammalian body tissue, or 1.0 /mm. In this study, the accuracy of the μa estimation was analyzed and its dependence on the μs' was clarified quantitatively in various situations expected in practice. 10% deviations in μs' resulted in about 30% error in μa estimation, in average. This suggested that the measurement or the appropriate estimation of μs' is required to utilize the proposed technique effectively. Through this analysis, the effectiveness and the limitation of the newly proposed technique were clarified, and the problems to be solved were identified.

  19. Profile modification and hot electron temperature from resonant absorption at modest intensity

    SciTech Connect

    Albritton, J.R.; Langdon, A.B.

    1980-10-13

    Resonant absorption is investigated in expanding plasmas. The momentum deposition associated with the ejection of hot electrons toward low density via wavebreaking readily exceeds that of the incident laser radiation and results in significant modification of the density profile at critical. New scaling of hot electron temperature with laser and plasma parameters is presented.

  20. Fiber-coupled laser-induced breakdown and Raman spectroscopy for flexible sample characterization with depth profiling capabilities

    NASA Astrophysics Data System (ADS)

    Glaus, Reto; Hahn, David W.

    2014-10-01

    A combined laser-induced breakdown spectroscopy (LIBS) and Raman spectroscopy system for depth profile analyses is presented. The system incorporates a single 532 nm laser source, which is delivered through an optical fiber to the sample site. The homogenized laser beam results in well-defined cylindrical craters with diameters of 100 μm. LIBS depth profiling analyses of metals was performed applying pulse energies of about 1 mJ. The application of up to 500 pulses allowed to drill through layers of several tens of microns, while observing sharp transitions at the layer interfaces. The capability of the system for Raman spectroscopy was investigated for various polymer samples by reducing the pulse energies below the respective ablation threshold. A combined Raman/LIBS depth profiling was applied to a polymer-coated metal. Additionally, the capability of the system for calibration-free LIBS quantification (CF-LIBS) was evaluated. Quantification of major elements in metallic reference materials showed good agreement with the certified values with relative deviations of less than 30%. Finally, the optimized system was applied for depth profiling and elemental composition analysis of ancient Roman bronze rings. Overall, the presented setup combines the high flexibility of a fiber-coupled system with Raman and micro-LIBS, making the system interesting for depth profiling and elemental quantification in archaeometric as well as industrial applications.

  1. Atmospheric Profiling Combining the Features of GPS ro & Mls: Satellite to Satellite Occultations Near Water & Ozone Absorption Lines

    NASA Astrophysics Data System (ADS)

    Kursinski, E. R.; Ward, D.; Otarola, A. C.; McGhee, J.; Reed, H.; Erickson, D.

    2015-12-01

    Assessing climate models & their predictions requires observations that determine the state of the real climate system precisely and unambiguously, independently from models. For this purpose, we have been developing a new orbiting remote sensing system called the Active Temperature, Ozone & Moisture Microwave Spectrometer (ATOMMS) which is a cross between GPS RO and the Microwave Limb Sounder. ATOMMS actively probes water vapor, ozone & other absorption lines at cm & mm wavelengths in a satellite to satellite occultation geometry to simultaneously profile temperature, pressure, water vapor and ozone as well as other important constituents. Individual profiles of water vapor, temperature & pressure heights will extend from near the surface into the mesosphere with ~1%, 0.4K and 10 m precision respectively and still better accuracy, with 100 m vertical resolution. Ozone profiles will extend upward from the upper troposphere. Line of sight wind profiles will extend upwards from the mid-stratosphere. ATOMMS is a doubly differential absorption system which eliminates drift and both sees clouds and sees thru them, to deliver performance in clouds within a factor of 2 of the performance in clear skies. This all-weather sampling combined with insensitivity to surface emissivity avoids sampling biases that limit most existing satellite records. ATOMMS will profile slant liquid water in clouds & rain and as well as turbulence via scintillations ("twinkling of a star"). Using prototype ATOMMS instrumentation that we developed with funding from NSF, several ATOMMS ground field campaigns precisely measured water vapor, cloud amount, rainfall, turbulence and absorption line spectroscopy. ATOMMS's dynamic range was demonstrated as water vapor was derived to 1% precision in optical depths up to 17. We are developing high altitude aircraft to aircraft instrumentation to further demonstrate ATOMMS performance, refine spectroscopy & support future field campaigns. Our vision is a

  2. Using the OMI aerosol index and absorption aerosol optical depth to evaluate the NASA MERRA Aerosol Reanalysis

    NASA Astrophysics Data System (ADS)

    Buchard, V.; da Silva, A. M.; Colarco, P. R.; Darmenov, A.; Randles, C. A.; Govindaraju, R.; Torres, O.; Campbell, J.; Spurr, R.

    2015-05-01

    A radiative transfer interface has been developed to simulate the UV aerosol index (AI) from the NASA Goddard Earth Observing System version 5 (GEOS-5) aerosol assimilated fields. The purpose of this work is to use the AI and aerosol absorption optical depth (AAOD) derived from the Ozone Monitoring Instrument (OMI) measurements as independent validation for the Modern Era Retrospective analysis for Research and Applications Aerosol Reanalysis (MERRAero). MERRAero is based on a version of the GEOS-5 model that is radiatively coupled to the Goddard Chemistry, Aerosol, Radiation, and Transport (GOCART) aerosol module and includes assimilation of aerosol optical depth (AOD) from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor. Since AI is dependent on aerosol concentration, optical properties and altitude of the aerosol layer, we make use of complementary observations to fully diagnose the model, including AOD from the Multi-angle Imaging SpectroRadiometer (MISR), aerosol retrievals from the AErosol RObotic NETwork (AERONET) and attenuated backscatter coefficients from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission to ascertain potential misplacement of plume height by the model. By sampling dust, biomass burning and pollution events in 2007 we have compared model-produced AI and AAOD with the corresponding OMI products, identifying regions where the model representation of absorbing aerosols was deficient. As a result of this study over the Saharan dust region, we have obtained a new set of dust aerosol optical properties that retains consistency with the MODIS AOD data that were assimilated, while resulting in better agreement with aerosol absorption measurements from OMI. The analysis conducted over the southern African and South American biomass burning regions indicates that revising the spectrally dependent aerosol absorption properties in the near-UV region improves the modeled-observed AI comparisons

  3. Species profiles in solid propellant flames using absorption and emission spectroscopy

    SciTech Connect

    Vanderhoff, J.A. )

    1991-03-01

    A windowed strand burner with a propellant feed mechanism has been used to characterize the steady-state burning of two composite propellants, M-30 and HMXI, at moderate pressure. Both emission and absorption spectroscopy have yielded profile data on three important combustion species: OH, NH, and CN. Relative appearances of these three species are inferred from emission intensity profiles, and absolute concentration profiles are calculated from the absorption data. This is the first absolute determination of these combustion intermediates in a propellant flame. The concentration measurements for OH indicate that the propellant flame temperatures are about 200 and 100 K below adiabatic for M-30 and HMXI, respectively. A maximum value of 43 ppm NH is found for the M-30 propellant flame. Fluctuations in the flame front of HMXI compromised the determination of maximum concentrations for NH and CN.

  4. Measurement of temperature profiles in flames by emission-absorption spectroscopy

    NASA Technical Reports Server (NTRS)

    Simmons, F. S.; Arnold, C. B.; Lindquist, G. H.

    1972-01-01

    An investigation was conducted to explore the use of infrared and ultraviolet emission-absorption spectroscopy for determination of temperature profiles in flames. Spectral radiances and absorptances were measured in the 2.7-micron H2O band and the 3064-A OH band in H2/O2 flames for several temperature profiles which were directly measured by a sodium line-reversal technique. The temperature profiles, determined by inversion of the infrared and ultraviolet spectra, showed an average disagreement with line-reversal measurements of 50 K for the infrared and 200 K for the ultraviolet at a temperature of 2600 K. The reasons for these discrepancies are discussed in some detail.

  5. Depth profiles of bacterioplankton assemblages and their activities in the Ross Sea

    NASA Astrophysics Data System (ADS)

    Celussi, Mauro; Cataletto, Bruno; Fonda Umani, Serena; Del Negro, Paola

    2009-12-01

    The identification of bacterial community structure has led, since the beginning of the 1990s, to the idea that bacterioplankton populations are stratified in the water column and that diverse lineages with mostly unknown phenotypes dominate marine microbial communities. The diversity of depth-related assemblages is also reflected in their patterns of activities, as bacteria affiliated to different groups can express different activities in a given ecosystem. We analysed bacterial assemblages (DGGE fingerprinting) and their activities (prokaryotic carbon production, protease, phosphatase, chitinase, beta-glucosidase and lipase activities) in two areas in the Ross Sea, differing mainly in their productivity regime: two stations are located in the Terra Nova Bay polynya area (highly productive during summer) and two close to Cape Adare (low phytoplankton biomass and activity). At every station a pronounced stratification of bacterial assemblages was identified, highlighting epipelagic communities differing substantially from the mesopelagic and the bathypelagic communities. Multivariate analysis suggested that pressure and indirectly light-affected variables (i.e. oxygen and fluorescence) had a great effect on the bacterial communities outcompeting the possible influences of temperature and dissolved organic carbon concentration. Generally activities decreased with depth even though a signal of the Circumpolar Deep Water (CDW) at one of the northern stations corresponded to an increase in some of the degradative activities, generating some 'hot spots' in the profile. We also found that similar assemblages express similar metabolic requirements reflected in analogous patterns of activity (similar degradative potential and leucine uptake rate). Furthermore, the presence of eukaryotic chloroplasts' 16S rDNA in deep samples highlighted how in some cases the dense surface-water formation (in this case High Salinity Shelf Water—HSSW) and downwelling can affect, at least

  6. Deuterium Depth Profile in Neutron-Irradiated Tungsten Exposed to Plasma

    SciTech Connect

    Masashi Shimada; G. Cao; Y. Hatano; T. Oda; Y. Oya; M. Hara; P. Calderoni

    2011-05-01

    The effect of radiation damage has been mainly simulated using high-energy ion bombardment. The ions, however, are limited in range to only a few microns into the surface. Hence, some uncertainty remains about the increase of trapping at radiation damage produced by 14 MeV fusion neutrons, which penetrate much farther into the bulk material. With the Japan-US joint research project: Tritium, Irradiations, and Thermofluids for America and Nippon (TITAN), the tungsten samples (99.99 % pure from A.L.M.T., 6mm in diameter, 0.2mm in thickness) were irradiated to high flux neutrons at 50 C and to 0.025 dpa in the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory (ORNL). Subsequently, the neutron-irradiated tungsten samples were exposed to a high-flux deuterium plasma (ion flux: 1021-1022 m-2s-1, ion fluence: 1025-1026 m-2) in the Tritium Plasma Experiment (TPE) at the Idaho National Laboratory (INL). First results of deuterium retention in neutron-irradiated tungsten exposed in TPE have been reported previously. This paper presents the latest results in our on-going work of deuterium depth profiling in neutron-irradiated tungsten via nuclear reaction analysis. The experimental data is compared with the result from non neutron-irradiated tungsten, and is analyzed with the Tritium Migration Analysis Program (TMAP) to elucidate the hydrogen isotope behavior such as retention and depth distribution in neutron-irradiated and non neutron-irradiated tungsten.

  7. Investigations Into the Interactions of a MALDI Matrix with Organic Thin Films Using C60+ SIMS Depth Profiling

    PubMed Central

    Lerach, Jordan O.; Keskin, Selda; Winograd, Nicholas

    2015-01-01

    Molecular depth profiling of multilayer organic films is now an established protocol for cluster secondary ion mass spectrometry (SIMS). This unique capability is exploited here to study the ionization mechanism associated with matrix-enhanced SIMS and possibly matrix assisted laser desorption/ionization (MALDI). Successful depth profiling experiments were performed on model bi-layer systems using 2,5-dihydroxybenzoic acid (DHB) as the matrix with dipalmitoylphosphatidylcholine (DPPC) or phenylalanine (PHE). The interaction between the matrix and organic analyte is monitored at the interface of the films. Tri-layer films with D2O as a thin-film sandwiched between the matrix and organic layers are also investigated to determine what role, if any, water plays during ionization. The results show successful depth profiles when taken at 90K. Mixing is observed at the interfaces of the films due to primary ion bombardment, but this mixing does not recreate the conditions necessary for ionization enhancement. PMID:26494930

  8. Millennial-scale hard rock erosion rates deduced from luminescence-depth profiles

    NASA Astrophysics Data System (ADS)

    Sohbati, R.; Liu, J.; Murray, A. S.; Jain, M.; Pederson, J. L.; Guralnik, B.; Egholm, D. L.; Gupta, S.

    2015-12-01

    Optically stimulated luminescence (OSL) is a well-established Quaternary dating method that is conventionally used to determine the time when sedimentary grains were last exposed to daylight. Recently, a very different approach to this concept has helped develop a new technique to estimate the length of time a rock surface was exposed to daylight. When a rock surface is first exposed to daylight the charge population (and so the latent luminescence signal) trapped in its constituent minerals (e.g. quartz and feldspar) starts to decrease. This charge had accumulated due to previous exposure to natural ionizing radiation. As the surface is exposed to light for longer periods, the latent luminescence signal is reduced farther into the rock. In a rock surface which has been exposed to light for a prolonged period (decades to millennia), the remaining luminescence will be zero (fully bleached) at the surface and then increase, initially exponentially, before approaching saturation at a depth where charge detrapping due to light penetration is negligible compared to the rate of charge trapping due to the environmental dose rate. By modelling the characteristic shape of luminescence resetting with depth into rock surfaces, Sohbati et al. (2012) proposed a new surface-exposure dating technique based on OSL. Here we further develop the current model to include the effect of erosion rate on luminescence-depth profiles. By fitting the model to local known-age calibration samples, we first determine the site-specific resetting rates of the luminescence signal at rock surfaces. We then use the calibration values in a numerical model to derive the steady-state erosion rate for rocks of different mineralogy and different geological settings. The preliminary erosion rates obtained from glacial and landslide granite boulders from the Chinese Pamir Plateau are ~1 mm.ka-1, whereas active streambeds of Permian sandstone in the Grabens district of Canyonlands National Park, Utah, are

  9. P2IMS depth profile analysis of high temperature boron oxynitride dielectric films

    NASA Astrophysics Data System (ADS)

    Badi, N.; Vijayaraghavan, S.; Benqaoula, A.; Tempez, A.; Tauziède, C.; Chapon, P.

    2014-02-01

    Existing silicon oxynitride (SiON) dielectric can only provide a very near term solution for the metal oxide semiconductor technology. The emerging high-k dielectric materials have a limited thermal stability and are prone to electrical behavior degradation which is associated with unwanted chemical reactions with silicon (Si). We investigated here applicability of amorphous boron oxynitride (BON) thin films as an emerging dielectric for high temperature capacitors. BON samples of thickness varying from 200 nm down to 10 nm were deposited in a high vacuum reactor using ion source assisted physical vapor deposition (PVD) technique. Plasma profiling ion mass spectrometry (P2IMS) was utilized to specifically determine the interface quality and best capacitor performance as a function of growth temperatures of a graded sample with alternate layers of deposited titanium (Ti) and BON layers on Si. P2IMS depth profiling of these layers were also performed to evaluate the stability of the dielectric layers and their efficacy against B dopant diffusion simulating processes occurring in activated polySi-based devices. For this purpose, BON layers were deposited on boron-isotope 10 (B10) implanted Si substrates and subsequently annealed at high temperatures up to 1050 °C for about 10 s. Results comparing inter-diffusion of B10 intensities at the interfaces of BON-Si and SiON-Si samples suggest suitability of BON as barrier layers against boron diffusion at high temperature. Stable Ti/BON/Ti capacitor behavior was achieved at optimum growth temperature of 600 °C of the BON dielectric layer. Capacitance change with frequency (10 kHz to 2 MHz) and temperature up to 400 °C is about 1% and 10%, respectively.

  10. ToF-SIMS Depth Profiling of Organic Films: A Comparison between Single Beam and Dual-beam Analysis

    PubMed Central

    Brison, J.; Muramoto, S.; Castner, David G.

    2010-01-01

    In dual-beam depth profiling, a high energy analysis beam and a lower energy etching beam are operated in series. Although the fluence of the analysis beam is usually kept well below the static SIMS limit, complete removal of the damage induced by the high energy analysis beam while maintaining a good depth resolution is difficult. In this study a plasma polymerized tetraglyme film is used as the model organic system and the dimensionless parameter R, (analysis beam fluence)/(total ion fluence), is introduced to quantify the degree of sample damage induced as a function of the analysis beam fluence. It was observed for a constant C60+ etching beam fluence, increasing the analysis fluence (and consequently increasing the R parameter) increased in the amount of damage accumulated in the sample. For Bin+ (n = 1 and 3) and C60+ depth profiling, minimal damage accumulation was observed up to R = 0.03, with a best depth resolution of 8 nm. In general, an increase in the Bin+ analysis fluence above this value resulted in a decrease in the molecular signals of the steady state region of the depth profile and a degradation of the depth resolution at the polymer/substrate interface. PMID:20383274

  11. Structural and magnetic depth profiles of magneto-ionic heterostructures beyond the interface limit.

    PubMed

    Gilbert, Dustin A; Grutter, Alexander J; Arenholz, Elke; Liu, Kai; Kirby, B J; Borchers, Julie A; Maranville, Brian B

    2016-01-01

    Electric field control of magnetism provides a promising route towards ultralow power information storage and sensor technologies. The effects of magneto-ionic motion have been prominently featured in the modification of interface characteristics. Here, we demonstrate magnetoelectric coupling moderated by voltage-driven oxygen migration beyond the interface in relatively thick AlOx/GdOx/Co(15 nm) films. Oxygen migration and Co magnetization are quantitatively mapped with polarized neutron reflectometry under electro-thermal conditioning. The depth-resolved profiles uniquely identify interfacial and bulk behaviours and a semi-reversible control of the magnetization. Magnetometry measurements suggest changes in the microstructure which disrupt long-range ferromagnetic ordering, resulting in an additional magnetically soft phase. X-ray spectroscopy confirms changes in the Co oxidation state, but not in the Gd, suggesting that the GdOx transmits oxygen but does not source or sink it. These results together provide crucial insight into controlling magnetism via magneto-ionic motion, both at interfaces and throughout the bulk of the films. PMID:27447691

  12. Electron beam and optical depth-profiling of quasi-bulk GaN

    SciTech Connect

    Chernyak, L.; Osinsky, A.; Nootz, G.; Schulte, A.; Jasinski, J.; Benamara, M.; Liliental-Weber, Z.; Look, D.C.; Molnar, R.J.

    2000-11-22

    Electron beam and optical depth-profiling of thick (5.5-64 mm) quasi-bulk n-type GaN samples, grown by hydride vapor-phase epitaxy (HVPE), were carried out using electron beam induced current (EBIC), micro-photoluminescence (PL) and transmission electron microscopy (TEM). The minority carrier diffusion length, L, was found to increase linearly from 0.25 mm, at a distance of about 5 mm from the GaN/sapphire interface, to 0.63 mm at the GaN surface, for a 36-mm-thick sample. The increase in L was accompanied by a corresponding increase in PL band-to-band radiative transition intensity as a function of distance from the GaN/sapphire interface. We attribute the latter changes in PL intensity and minority carrier diffusion length to a reduced carrier mobility and lifetime at the interface, due to scattering at threading dislocations. The results of EBIC and PL measurements are in good agreement with the values for dislocation density, obtained using TEM.

  13. Electron beam and optical depth profiling of quasibulk GaN

    NASA Astrophysics Data System (ADS)

    Chernyak, L.; Osinsky, A.; Nootz, G.; Schulte, A.; Jasinski, J.; Benamara, M.; Liliental-Weber, Z.; Look, D. C.; Molnar, R. J.

    2000-10-01

    Electron beam and optical depth profiling of thick (5.5-64 μm) quasibulk n-type GaN samples, grown by hydride vapor-phase epitaxy, were carried out using electron beam induced current (EBIC), microphotoluminescence (PL), and transmission electron microscopy (TEM). The minority carrier diffusion length, L, was found to increase linearly from 0.25 μm, at a distance of about 5 μm from the GaN/sapphire interface, to 0.63 μm at the GaN surface, for a 36-μm-thick sample. The increase in L was accompanied by a corresponding increase in PL band-to-band radiative transition intensity as a function of distance from the GaN/sapphire interface. We attribute the latter changes in PL intensity and minority carrier diffusion length to a reduced carrier mobility and lifetime at the interface, due to scattering at threading dislocations. The results of EBIC and PL measurements are in good agreement with the values for dislocation density obtained using TEM.

  14. Electron beam and optical depth profiling of quasibulk GaN

    SciTech Connect

    Chernyak, L.; Osinsky, A.; Nootz, G.; Schulte, A.; Jasinski, J.; Benamara, M.; Liliental-Weber, Z.; Look, D. C.; Molnar, R. J.

    2000-10-23

    Electron beam and optical depth profiling of thick (5.5--64 {mu}m) quasibulk n-type GaN samples, grown by hydride vapor-phase epitaxy, were carried out using electron beam induced current (EBIC), microphotoluminescence (PL), and transmission electron microscopy (TEM). The minority carrier diffusion length, L, was found to increase linearly from 0.25 {mu}m, at a distance of about 5 {mu}m from the GaN/sapphire interface, to 0.63 {mu}m at the GaN surface, for a 36-{mu}m-thick sample. The increase in L was accompanied by a corresponding increase in PL band-to-band radiative transition intensity as a function of distance from the GaN/sapphire interface. We attribute the latter changes in PL intensity and minority carrier diffusion length to a reduced carrier mobility and lifetime at the interface, due to scattering at threading dislocations. The results of EBIC and PL measurements are in good agreement with the values for dislocation density obtained using TEM.

  15. Structural and magnetic depth profiles of magneto-ionic heterostructures beyond the interface limit

    PubMed Central

    Gilbert, Dustin A.; Grutter, Alexander J.; Arenholz, Elke; Liu, Kai; Kirby, B. J.; Borchers, Julie A.; Maranville, Brian B.

    2016-01-01

    Electric field control of magnetism provides a promising route towards ultralow power information storage and sensor technologies. The effects of magneto-ionic motion have been prominently featured in the modification of interface characteristics. Here, we demonstrate magnetoelectric coupling moderated by voltage-driven oxygen migration beyond the interface in relatively thick AlOx/GdOx/Co(15 nm) films. Oxygen migration and Co magnetization are quantitatively mapped with polarized neutron reflectometry under electro-thermal conditioning. The depth-resolved profiles uniquely identify interfacial and bulk behaviours and a semi-reversible control of the magnetization. Magnetometry measurements suggest changes in the microstructure which disrupt long-range ferromagnetic ordering, resulting in an additional magnetically soft phase. X-ray spectroscopy confirms changes in the Co oxidation state, but not in the Gd, suggesting that the GdOx transmits oxygen but does not source or sink it. These results together provide crucial insight into controlling magnetism via magneto-ionic motion, both at interfaces and throughout the bulk of the films. PMID:27447691

  16. Structural and magnetic depth profiles of magneto-ionic heterostructures beyond the interface limit

    NASA Astrophysics Data System (ADS)

    Gilbert, Dustin A.; Grutter, Alexander J.; Arenholz, Elke; Liu, Kai; Kirby, B. J.; Borchers, Julie A.; Maranville, Brian B.

    2016-07-01

    Electric field control of magnetism provides a promising route towards ultralow power information storage and sensor technologies. The effects of magneto-ionic motion have been prominently featured in the modification of interface characteristics. Here, we demonstrate magnetoelectric coupling moderated by voltage-driven oxygen migration beyond the interface in relatively thick AlOx/GdOx/Co(15 nm) films. Oxygen migration and Co magnetization are quantitatively mapped with polarized neutron reflectometry under electro-thermal conditioning. The depth-resolved profiles uniquely identify interfacial and bulk behaviours and a semi-reversible control of the magnetization. Magnetometry measurements suggest changes in the microstructure which disrupt long-range ferromagnetic ordering, resulting in an additional magnetically soft phase. X-ray spectroscopy confirms changes in the Co oxidation state, but not in the Gd, suggesting that the GdOx transmits oxygen but does not source or sink it. These results together provide crucial insight into controlling magnetism via magneto-ionic motion, both at interfaces and throughout the bulk of the films.

  17. D-depth profiling in as-implanted and annealed Li-based breeder blanket ceramics

    NASA Astrophysics Data System (ADS)

    Carella, Elisabetta; Gonzalez, Maria; Gonzalez-Arrabal, Raquel

    2013-07-01

    In future power plants (i.e. DEMO), the nuclear fusion of hydrogen isotopes will be used for energy production. The behaviour of hydrogen isotopes in lithium-enriched ceramics for breeder blankets (BBs) is one of the most important items to be understood. In this paper we present the chemical, microstructural and morphological features of Li4SiO4, Li2TiO3 and a third ceramic candidate with a higher Li:Si proportion (3:1), implanted with D at an energy of 100 keV and at room temperature at a fluence of 1 × 1017 cm-2. The D depth-profile in as-implanted and annealed ceramics (at T ⩽ 200 °C) was characterised by Resonance Nuclear Reaction Analysis (RNRA). The RNRA data indicate that the total amount of D is retained at room temperature, while annealing at 100 °C promotes D release and annealing at T ⩾ 150 °C drives D to completely desorb from all the studied ceramics. D release will be discussed as a function of the microstructurural and morphological features of each material.

  18. Composition of the outermost layer and concentration depth profiles of ammonium nitrate ionic liquid surfaces.

    PubMed

    Ridings, Christiaan; Warr, Gregory G; Andersson, Gunther G

    2012-12-14

    Differences in the surface structure of protic ionic liquids (ILs) with three different cations and a common anion; ethyl-, propyl- and 2-hydroxyethyl- (or ethanol-) ammonium nitrate (EAN, PAN and EtAN, respectively) have been observed by neutral impact collision ion scattering spectroscopy (NICISS) and metastable induced electron spectroscopy/ultraviolet photoelectron spectroscopy (MIES/UPS). NICISS is used to determine the concentration depth profiles of the elements in each IL and it reveals an enrichment of cation alkyl chains of PAN and EtAN in the outermost layer compared to EAN, and a corresponding depletion of nitrate from the outermost layer of the EtAN surface. MIES probes the molecular orbitals of only the species in the outermost layer of a sample and confirms that, while both the anion and the cation are present to some degree at the surface of all three ILs, the cation is enriched to a greater extent at the surface of PAN and EtAN compared to EAN. PMID:23103987

  19. Bioturbation depths, rates and processes in Massachusetts Bay sediments inferred from modeling of 210Pb and 239 + 240Pu profiles

    USGS Publications Warehouse

    Crusius, John; Bothner, Michael H.; Sommerfield, Christopher K.

    2004-01-01

    Profiles of 210Pb and 239 + Pu from sediment cores collected throughout Massachusetts Bay (water depths of 36-192 m) are interpreted with the aid of a numerical sediment-mixing model to infer bioturbation depths, rates and processes. The nuclide data suggest extensive bioturbation to depths of 25-35 cm. Roughly half the cores have 210Pb and 239 + 240Pu profiles that decrease monotonically from the surface and are consistent with biodiffusive mixing. Bioturbation rates are reasonably well constrained by these profiles and vary from ~0.7 to ~40 cm2 yr-1. As a result of this extensive reworking, however, sediment ages cannot be accurately determined from these radionuclides and only upper limits on sedimentation rates (of ~0.3 cm yr-1) can be inferred. The other half of the radionuclide profiles are characterized by subsurface maxima in each nuclide, which cannot be reproduced by biodiffusive mixing models. A numerical model is used to demonstrate that mixing caused by organisms that feed at the sediment surface and defecate below the surface can cause the subsurface maxima, as suggested by previous work. The deep penetration depths of excess 210Pb and 239 + 240Pu suggest either that the organisms release material over a range of >15 cm depth or that biodiffusive mixing mediated by other organisms is occurring at depth. Additional constraints from surficial sediment 234Th data suggest that in this half of the cores, the vast majority of the present-day flux of recent, nuclide-bearing material to these core sites is transported over a timescale of a month or more to a depth of a few centimeters below the sediment surface. As a consequence of the complex mixing processes, surface sediments include material spanning a range of ages and will not accurately record recent changes in contaminant deposition.

  20. Profiling biopharmaceutical deciding properties of absorption of lansoprazole enteric-coated tablets using gastrointestinal simulation technology.

    PubMed

    Wu, Chunnuan; Sun, Le; Sun, Jin; Yang, Yajun; Ren, Congcong; Ai, Xiaoyu; Lian, He; He, Zhonggui

    2013-09-10

    The aim of the present study was to correlate in vitro properties of drug formulation to its in vivo performance, and to elucidate the deciding properties of oral absorption. Gastrointestinal simulation technology (GST) was used to simulate the in vivo plasma concentration-time curve and was implemented by GastroPlus™ software. Lansoprazole, a typical BCS class II drug, was chosen as a model drug. Firstly, physicochemical and pharmacokinetic parameters of lansoprazole were determined or collected from literature to construct the model. Validation of the developed model was performed by comparison of the predicted and the experimental plasma concentration data. We found that the predicted curve was in a good agreement with the experimental data. Then, parameter sensitivity analysis (PSA) was performed to find the key parameters of oral absorption. The absorption was particularly sensitive to dose, solubility and particle size for lansoprazole enteric-coated tablets. With a single dose of 30 mg and the solubility of 0.04 mg/ml, the absorption was complete. A good absorption could be achieved with lansoprazole particle radius down to about 25 μm. In summary, GST is a useful tool for profiling biopharmaceutical deciding properties of absorption of lansoprazole enteric-coated tablets and guiding the formulation optimization. PMID:23806811

  1. Depth profiling of electrically non-conductive layered samples by RF-GDOES and HFM plasma SNMS

    NASA Astrophysics Data System (ADS)

    Hodoroaba, Vasile-Dan; Unger, Wolfgang E. S.; Jenett, Holger; Hoffmann, Volker; Hagenhoff, Birgit; Kayser, Sven; Wetzig, Klaus

    2001-07-01

    The work is intended to compare the capabilities of two similar depth profiling techniques to analyse electrically non-conductive samples. In order to get a better evaluation of the depth resolution, various multilayer sandwiches, such as SiO 2/TiO 2 and Si 3N 4/SiO 2 deposited on glass substrates have been investigated. Optimised depth profiles are presented for both methods, glow discharge optical emission spectrometry (GDOES) and radiofrequency mode (known as "HFM" in the SNMS literature) of plasma secondary neutral mass spectrometry (SNMS). The optimisation procedure, necessary to get the best set of plasma parameters, which result in the optimal depth resolution, is also described for one selected sample. Additionally, sputtering crater profilometry was carried out in order to check out the flatness of the sputtered crater. The influence of the thickness of the sample substrate on the sputtering rate is discussed. Finally, advantages and disadvantages of the use of these two depth profiling methods, especially for the non-conductive samples, are concluded from this comparative study. Time-of-flight secondary ion mass spectrometry (ToF-SIMS) analysis of a cross-sectioned sample was carried out in order to get supplementary information.

  2. Rotational Profiles of Molecular Absorption Bands in Astrophysically Relevant Conditions: Ab-Initio Approach

    SciTech Connect

    Malloci, Giuliano; Mulas, Giacomo; Cappellini, Giancarlo; Satta, Guido; Porceddu, Ignazio; Benvenuti, Piero

    2004-05-01

    A theoretical study of rotational profiles of molecular absorption bands is essential for direct comparison with observations of diffuse interstellar bands. Applications using gaussian quantum-chemical approach within DFT are presented. Structural and vibrational properties of the polycyclic aromatic hydrocarbon ovalene cation (C32H14+) are obtained. We discuss the expected profile of the first electronic transition of such molecule, obtained with a Monte Carlo model of its rotation in the physical conditions of low temperatures and absence of collisions which are characteristic of the interstellar medium (ISM).

  3. Ultrathin oxide interfaces on 6H-SiC formed by plasma hydrogenation: Ultra shallow depth profile study

    NASA Astrophysics Data System (ADS)

    Xie, Xianning; Loh, Kian Ping

    2002-11-01

    Silicon oxide ultrathin films grown on silicon carbide (6H-SiC) by plasma hydrogenation have been studied using ultrashallow depth profiling with time-of-flight secondary ion mass spectrometry. Plasma hydrogenation gives rise to an epitaxial RADICAL:[[RADICAND:[3

  4. Differential absorption lidar technique for measurement of the atmospheric pressure profile

    NASA Technical Reports Server (NTRS)

    Korb, C. L.; Weng, C. Y.

    1983-01-01

    A new two-wavelength lidar technique for remotely measuring the pressure profile using the trough absorption region between two strong lines in the oxygen A band is described. The theory of integrated vertical path, differential ranging, and horizontal-path pressure measurements is given, with methods to desensitize and correct for temperature effects. The properties of absorption troughs are described and shown to reduce errors due to laser frequency jitter by up to two orders of magnitude. A general analysis, including laser bandwidth effects, demonstrates that pressure measurements with an integrated-vertical-path technique are typically fifty times more accurate than with a differential ranging technique. Simulations show 0.1-0.3 percent accuracy for ground and Shuttle-based pressure-profile and surface-pressure experiments.

  5. Absorption-line profiles in a companion spectrum of a mass-losing cool supergiant

    NASA Technical Reports Server (NTRS)

    Rodrigues, Liliya L.; Boehm-Vitense, Erika

    1992-01-01

    Cool star winds can best be observed in resonance absorption lines seen in the spectrum of a hot companion, due to the wind passing in front of the blue star. We calculated absorption line profiles that would be seen in the ultraviolet part of the blue companion spectrum. Line profiles are derived for different radial dependences of the cool star wind and for different orbital phases of the binary. Bowen and Wilson find theoretically that stellar pulsations drive mass loss. We therefore apply our calculations to the Cepheid binary S Muscae which has a B5V companion. We find an upper limit for the Cepheid mass loss of M less than or equal to 7 x 10 (exp -10) solar mass per year provided that the stellar wind of the companion does not influence the Cepheid wind at large distances.

  6. Absorption line profiles in a companion spectrum of a mass losing cool supergiant

    NASA Technical Reports Server (NTRS)

    Rodrigues, Liliya L.; Boehm-Vitense, Erika

    1990-01-01

    Cool star winds can best be observed in resonance absorption lines seen in the spectrum of a hot companion, due to the wind passing in front of the blue star. We calculated absorption line profiles that would be seen in the ultraviolet part of the blue companion spectrum. Line profiles are derived for different radial dependences of the cool star wind and for different orbital phases of the binary. Bowen and Wilson find theoretically that stellar pulsations drive mass loss. We therefore apply our calculations to the Cepheid binary S Muscae which has a B5V companion. We find an upper limit for the Cepheid mass loss of M less than or equal to 7 x 10(exp -10) solar mass per year provided that the stellar wind of the companion does not influence the Cepheid wind at large distances.

  7. Differential absorption lidars for remote sensing of atmospheric pressure and temperature profiles

    NASA Technical Reports Server (NTRS)

    Korb, C. Laurence; Schwemmer, Geary K.; Famiglietti, Joseph; Walden, Harvey; Prasad, Coorg

    1995-01-01

    A near infrared differential absorption lidar technique is developed using atmospheric oxygen as a tracer for high resolution vertical profiles of pressure and temperature with high accuracy. Solid-state tunable lasers and high-resolution spectrum analyzers are developed to carry out ground-based and airborne measurement demonstrations and results of the measurements presented. Numerical error analysis of high-altitude airborne and spaceborne experiments is carried out, and system concepts developed for their implementation.

  8. Enhancing optical absorption in InP and GaAs utilizing profile etching

    NASA Technical Reports Server (NTRS)

    Bailey, Sheila G.; Fatemi, Navid S.; Landis, Geoffrey A.

    1991-01-01

    The current state of profile etching in GaAs and InP is summarized, including data on novel geometries attainable as a function of etchant temperature, composition, and rate; substrate orientation; carrier concentration; and oxide thickness between substrate and photoresist. V-grooved solar cells were manufactured with both GaAs and InP, and the improved optical absorption was demonstrated. Preferred parameters for various applications are listed and discussed.

  9. Enhancing optical absorption in InP and GaAs utilizing profile etching

    NASA Technical Reports Server (NTRS)

    Bailey, Sheila G.; Fatemi, Navid S.; Landis, Geoffrey A.

    1991-01-01

    The current state of profile etching in GaAs and InP is summarized, including data on novel geometries attainable as a function of etchant temperature, composition, and rate; substrate orientation; carrier concentration; and oxide thickness between substrate and photoresist. V-grooved solar cells have been manufactured with both GaAs and InP, and the improved optical absorption demonstrated. Preferred parameters for various applications are listed and discussed.

  10. Using the OMI Aerosol Index and Absorption Aerosol Optical Depth to Evaluate the NASA MERRA Aerosol Reanalysis.

    NASA Astrophysics Data System (ADS)

    Buchard, V.; da Silva, A. M., Jr.; Colarco, P. R.; Darmenov, A.; Govindaraju, R.

    2014-12-01

    A radiative transfer interface has been developed to simulate the UV Aerosol Index (AI) from the NASA Goddard Earth Observing System version 5 (GEOS-5) aerosol assimilated fields. The purpose of this work is to use the AI derived from the Ozone Monitoring Instrument (OMI) measurements as independent validation for the Modern Era Retrospective analysis for Research and Applications Aerosol Reanalysis (MERRAero). In this presentation we show comparisons of model produced AI with the corresponding OMI measurements during several months of 2007 characterized by a good sampling of dust and biomass burning events. In parallel, model produced Absorption Aerosol Optical Depth (AAOD) were compared to OMI AAOD for the same period, identifying regions where the model representation of absorbing aerosols were deficient. Since AI is dependent on aerosol concentration, optical properties and altitude of the aerosol layer, we make use of complementary observations to fully diagnose the model, including AOD from the Multi-angle Imaging SpectroRadiometer (MISR) and the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors, aerosol retrievals from the Aerosol Robotic Network (AERONET) and attenuated backscatter coefficients from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) mission to ascertain misplacement of plume height by the model.

  11. Depth profiling of gold nanoparticles and characterization of point spread functions in reconstructed and human skin using multiphoton microscopy.

    PubMed

    Labouta, Hagar I; Hampel, Martina; Thude, Sibylle; Reutlinger, Katharina; Kostka, Karl-Heinz; Schneider, Marc

    2012-01-01

    Multiphoton microscopy has become popular in studying dermal nanoparticle penetration. This necessitates studying the imaging parameters of multiphoton microscopy in skin as an imaging medium, in terms of achievable detection depths and the resolution limit. This would simulate real-case scenarios rather than depending on theoretical values determined under ideal conditions. This study has focused on depth profiling of sub-resolution gold nanoparticles (AuNP) in reconstructed (fixed and unfixed) and human skin using multiphoton microscopy. Point spread functions (PSF) were determined for the used water-immersion objective of 63×/NA = 1.2. Factors such as skin-tissue compactness and the presence of wrinkles were found to deteriorate the accuracy of depth profiling. A broad range of AuNP detectable depths (20-100 μm) in reconstructed skin was observed. AuNP could only be detected up to ∼14 μm depth in human skin. Lateral (0.5 ± 0.1 μm) and axial (1.0 ± 0.3 μm) PSF in reconstructed and human specimens were determined. Skin cells and intercellular components didn't degrade the PSF with depth. In summary, the imaging parameters of multiphoton microscopy in skin and practical limitations encountered in tracking nanoparticle penetration using this approach were investigated. PMID:22147676

  12. P Cygni profiles in zeta Ophiuchi and zeta Puppis. [far UV absorption lines

    NASA Technical Reports Server (NTRS)

    Morton, D. C.

    1976-01-01

    Detailed P Cygni profiles are plotted using data from selected regions of the far-UV spectra of zeta OPh and zeta Pup obtained by the Copernicus satellite. Equivalent widths and velocity shifts of both emission and absorption features are also presented. For zeta Oph, it is found that only the C IV and N V resonance lines exhibit the P Cygni phenomenon; for zeta Pup, the resonance lines of C III, N III, Si IV, C IV, P V, S VI, N V, and O VI all show strong P Cygni lines, although the emission component seems to be absent in N III. For both stars, it is shown that parts of most absorption profiles exceed the escape velocity, indicating mass ejection. The short-wavelength edges of the resonance lines are found to average about -1590 km/s in zeta Oph and about -2660 km/s in zeta Pup, with no significant dependence on ionization potential. It is noted that the equivalent width of the emission component is always considerably less than that of the absorption component, suggesting that absorption occurs close to the stellar surface.

  13. Confocal Raman microspectroscopy on excised human skin: uncertainties in depth profiling and mathematical correction applied to dermatological drug permeation.

    PubMed

    Tfayli, A; Piot, O; Manfait, M

    2008-05-01

    Confocal Raman microspectroscopy represents the advantage of giving structural and conformational information on samples without any destructive treatment. Recently, several studies were achieved to study the skin hydration, endogenous and exogenous molecules repartition in the skin using the confocal feature of this technique. Meanwhile, when working through a material boundary with a different refractive index, the main limitation remains the spatial precision, especially the distortion in the depth and the depth resolution. Recently, several authors described mathematical models to correct the depth and the resolution values. In this study, we combined theoretical approaches, proposed by different authors with experimental measurements to try to find out the most appropriate approach for correction. We then applied the corrections on in-depth profiles tracking the penetration of Metronidazole, a drug produced by Galderma for rosacea treatment, through excised human skin. PMID:19343645

  14. Depth profile characterization of Zn-TiO2 nanocomposite films by pulsed radiofrequency glow discharge-optical emission spectrometry.

    PubMed

    Alberts, Deborah; Fernández, Beatriz; Frade, Tania; Gomes, Anabela; Pereira, Maria Isabel da Silva; Pereiro, Rosario; Sanz-Medel, Alfredo

    2011-04-15

    In recent years particular effort is being devoted towards the development of radiofrequency (rf) pulsed glow discharges (GDs) coupled to optical emission spectrometry (OES) for depth profile analysis of materials with technological interest. In this work, pulsed rf-GD-OES is investigated for the fast and sensitive depth characterization of Zn-TiO(2) nanocomposite films deposited on conductive substrates (Ti and steel). The first part of this work focuses on assessing the advantages of pulsed GDs, in comparison with the continuous GD, in terms of analytical emission intensities and emission yields. Next, the capability of pulsed rf-GD-OES for determination of thickness and compositional depth profiles is demonstrated by resorting to a simple multi-matrix calibration procedure. A rf forward power of 75 W, a pressure of 600 Pa, 10 kHz pulse frequency and 50% duty cycle were selected as GD operation parameters.Quantitative depth profiles obtained with the GD proposed methodology for Zn-TiO(2) nanocomposite films, prepared by the occlusion electrodeposition method using pulsed reverse current electrolysis, have proved to be in good agreement with results achieved by complementary techniques, including scanning electron microscopy and inductively coupled plasma-mass spectrometry. The work carried out demonstrates that pulsed rf-GD-OES is a promising tool for the fast analytical characterization of nanocomposite films. PMID:21376989

  15. Retrieval of Aerosol Profiles using Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS)

    NASA Astrophysics Data System (ADS)

    Yilmaz, Selami; Frieß, Udo; Apituley, Arnoud; Henzing, Bas; Baars, Holger; Heese, Birgit; Althausen, Dietrich; Adam, Mariana; Putaud, Jean-Philippe; Zieger, Paul; Platt, Ulrich

    2010-05-01

    Multi Axis Differential Absorption Spectroscopy (MAX-DOAS) is a well established measurement technique to derive atmospheric trace gas profiles. Using MAX-DOAS measurements of trace gases with a known vertical profile, like the oxygen-dimer O4, it is possible to retrieve information on atmospheric aerosols. Based on the optimal estimation method, we have developed an algorithm which fits simultaneously measured O4 optical densities and relative intensities at several wavelengths and elevation angles to values simulated by a radiative transfer model. Retrieval parameters are aerosol extinction profile and optical properties such as single scattering albedo, phase function and Angström exponent. In 2008 and 2009 several intercomparison campaigns with established aerosol measurement techniques took place in Cabauw/Netherlands, Melpitz/Germany, Ispra/Italy and Leipzig/Germany, where simultaneous DOAS, lidar, Sun photometer and Nephelometer measurements were performed. Here we present results of the intercomparisons for cloud free conditions. The correlation of the aerosol optical thickness retrieved by the DOAS technique and the Sun photometer shows coefficients of determination from 0.96 to 0.98 and slopes from 0.94 to 1.07. The vertical structure of the DOAS retrieved aerosol extinction profiles compare favourably with the structures seen by the backscatter lidar. However, the vertical spatial development of the boundary layer is reproduced with a lower resolution by the DOAS technique. Strategies for the near real-time retrieval of trace gas profiles, aerosol profiles and optical properties will be discussed as well.

  16. Insights into biodegradation through depth-resolved microbial community functional and structural profiling of a crude-oil contaminant plume.

    PubMed

    Fahrenfeld, Nicole; Cozzarelli, Isabelle M; Bailey, Zach; Pruden, Amy

    2014-10-01

    Small-scale geochemical gradients are a key feature of aquifer contaminant plumes, highlighting the need for functional and structural profiling of corresponding microbial communities on a similar scale. The purpose of this study was to characterize the microbial functional and structural diversity with depth across representative redox zones of a hydrocarbon plume and an adjacent wetland, at the Bemidji Oil Spill site. A combination of quantitative PCR, denaturing gradient gel electrophoresis, and pyrosequencing were applied to vertically sampled sediment cores. Levels of the methanogenic marker gene, methyl coenzyme-M reductase A (mcrA), increased with depth near the oil body center, but were variable with depth further downgradient. Benzoate degradation N (bzdN) hydrocarbon-degradation gene, common to facultatively anaerobic Azoarcus spp., was found at all locations, but was highest near the oil body center. Microbial community structural differences were observed across sediment cores, and bacterial classes containing known hydrocarbon degraders were found to be low in relative abundance. Depth-resolved functional and structural profiling revealed the strongest gradients in the iron-reducing zone, displaying the greatest variability with depth. This study provides important insight into biogeochemical characteristics in different regions of contaminant plumes, which will aid in improving models of contaminant fate and natural attenuation rates. PMID:24760171

  17. Insights into biodegradation through depth-resolved microbial community functional and structural profiling of a crude-oil contaminant plume

    USGS Publications Warehouse

    Fahrenfeld, Nicole; Cozzarelli, Isabelle M.; Bailey, Zach; Pruden, Amy

    2014-01-01

    Small-scale geochemical gradients are a key feature of aquifer contaminant plumes, highlighting the need for functional and structural profiling of corresponding microbial communities on a similar scale. The purpose of this study was to characterize the microbial functional and structural diversity with depth across representative redox zones of a hydrocarbon plume and an adjacent wetland, at the Bemidji Oil Spill site. A combination of quantitative PCR, denaturing gradient gel electrophoresis, and pyrosequencing were applied to vertically sampled sediment cores. Levels of the methanogenic marker gene, methyl coenzyme-M reductase A (mcrA), increased with depth near the oil body center, but were variable with depth further downgradient. Benzoate degradation N (bzdN) hydrocarbon-degradation gene, common to facultatively anaerobic Azoarcus spp., was found at all locations, but was highest near the oil body center. Microbial community structural differences were observed across sediment cores, and bacterial classes containing known hydrocarbon degraders were found to be low in relative abundance. Depth-resolved functional and structural profiling revealed the strongest gradients in the iron-reducing zone, displaying the greatest variability with depth. This study provides important insight into biogeochemical characteristics in different regions of contaminant plumes, which will aid in improving models of contaminant fate and natural attenuation rates.

  18. Iron isotope composition of the suspended matter along depth and lateral profiles in the Amazon River and its tributaries

    NASA Astrophysics Data System (ADS)

    dos Santos Pinheiro, Giana Márcia; Poitrasson, Franck; Sondag, Francis; Vieira, Lucieth Cruz; Pimentel, Márcio Martins

    2013-07-01

    Samples of suspended matter were collected at different locations, seasons, depths and lateral profiles in the Amazon River and three of its main tributaries, the Madeira, the Solimões and the Negro rivers. Their iron isotope compositions were studied in order to understand the iron cycle and investigate the level of isotopic homogeneity at the river cross-section scale. Samples from four depth profiles and three lateral profiles analyzed show suspended matter δ57Fe values (relative to IRMM-14) between -0.501 ± 0.075‰ and 0.196 ± 0.083‰ (2SE). Samples from the Negro River, a blackwater river, yield the negative values. Samples from other stations (whitewater rivers, the Madeira, the Solimões and the Amazon) show positive values, which are indistinguishable from the average composition of the continental crust (δ57FeIRMM-14 ˜ 0.1‰). Individual analyses of the depth and lateral profiles show no significant variation in iron isotope signatures, indicating that, in contrast to certain chemical or other isotopic tracers, one individual subsurface sample is representative of river deeper waters. This also suggests that, instead of providing detailed information on the riverine iron cycling, iron isotopes of particulate matter in rivers will rather yield a general picture of the iron sources.

  19. DS86 neutron dose: Monte Carlo analysis for depth profile of 152Eu activity in a large stone sample.

    PubMed

    Endo, S; Iwatani, K; Oka, T; Hoshi, M; Shizuma, K; Imanaka, T; Takada, J; Fujita, S; Hasai, H

    1999-06-01

    The depth profile of 152Eu activity induced in a large granite stone pillar by Hiroshima atomic bomb neutrons was calculated by a Monte Carlo N-Particle Transport Code (MCNP). The pillar was on the Motoyasu Bridge, located at a distance of 132 m (WSW) from the hypocenter. It was a square column with a horizontal sectional size of 82.5 cm x 82.5 cm and height of 179 cm. Twenty-one cells from the north to south surface at the central height of the column were specified for the calculation and 152Eu activities for each cell were calculated. The incident neutron spectrum was assumed to be the angular fluence data of the Dosimetry System 1986 (DS86). The angular dependence of the spectrum was taken into account by dividing the whole solid angle into twenty-six directions. The calculated depth profile of specific activity did not agree with the measured profile. A discrepancy was found in the absolute values at each depth with a mean multiplication factor of 0.58 and also in the shape of the relative profile. The results indicated that a reassessment of the neutron energy spectrum in DS86 is required for correct dose estimation. PMID:10494148

  20. Implementation of heavy-ion elastic recoil detection analysis at JANNUS-Saclay for quantitative helium depth profiling

    NASA Astrophysics Data System (ADS)

    Loussouarn, T.; Beck, L.; Trocellier, P.; Brimbal, D.; Leprêtre, F.; Bordas, E.; Vaubaillon, S.; Serruys, Y.; Lefaix-Jeuland, H.

    2015-10-01

    Quantitative depth profiling measurements of implanted light elements is an important issue for electronics and nuclear applications. Conventional elastic recoil detection analysis (ERDA) has been improved by using heavy ions as incident particles for quantitatively profiling helium in materials. A new system has been implemented on the triple beam irradiation platform JANNUS at Saclay devoted to carry out HI-ERDA measurements. This device is dedicated to helium depth profiling using a 15 MeV 16O5+ incident ion beam. Capabilities of the technique (quantitative analysis, resolution and limit of detection) were tested on samples of known composition. For the first time, 4He depth profiles in pure α-iron, as-implanted and annealed, are obtained. HI-ERDA measurements have shown that helium release in pure α-iron can be described by a succession of two steps, the first having a slow kinetics below 700 °C and the second with a fast kinetics above 700 °C.

  1. Aluminum 26, {sup 10}Be, and {sup 36}Cl depth profiles in the Canyon Diablo iron meteorite

    SciTech Connect

    Michlovich, E.S.; Elmore, D.; Vogt, S.; Lipschutz, M.E.; Masarik, J.; Reedy, R.C.

    1994-11-25

    The authors have measured activities of the long-lived cosmogenic radionuclides {sup 26}Al, {sup 10}Be, and {sup 36}Cl in 12 fragments of the iron meteorite Canyon Diablo and have constructed production rate-versus-depth profiles of those radionuclides. Profiles determined using differential particle fluxes calculated with the LAHET code system are in good agreement with {sup 26}Al, {sup 10}Be, and {sup 36}Cl experimental data, but the agreement for {sup 36}Cl was obtained only after neutron-induced cross sections were modified. Profiles calculated with lunar particle fluxes are much lower than experimental Canyon Diablo profiles. The cosmic ray exposure ages of most samples are near 540 m.y. 34 refs., 4 figs., 2 tabs.

  2. Sulcal Depth-Position Profile Is a Genetically Mediated Neuroscientific Trait: Description and Characterization in the Central Sulcus

    PubMed Central

    Kochunov, Peter; Cykowski, Matthew D.; Kent, Jack W.; Laird, Angela R.; Lancaster, Jack L.; Blangero, John; Glahn, David C.; Fox, Peter T.

    2013-01-01

    Genetic and environmental influences on brain morphology were assessed in an extended-pedigree design by extracting depth-position profiles (DPP) of the central sulcus (CS). T1-weighted magnetic resonance images were used to measure CS length and depth in 467 human subjects from 35 extended families. Three primary forms of DPPs were observed. The most prevalent form, present in 70% of subjects, was bimodal, with peaks near hand and mouth regions. Trimodal and unimodal configurations accounted for 15 and 8%, respectively. Genetic control accounted for 56 and 66% of between-subject variance in average CS depth and length, respectively, and was not significantly influenced by environmental factors. Genetic control over CS depth ranged from 1 to 50% across the DPP. Areas of peak heritability occurred at locations corresponding to hand and mouth areas. Left and right analogous CS depth measurements were strongly pleiotropic. Shared genetic influence lessened as the distance between depth measurements was increased. We argue that DPPs are powerful phenotypes that should inform genetic influence of more complex brain regions and contribute to gene discovery efforts. PMID:24068828

  3. Re-evaluation of pulsed photothermal radiometric profiling in samples with spectrally varied infrared absorption coefficient.

    PubMed

    Majaron, Boris; Milanic, Matija

    2007-02-21

    Spectral variation of the sample absorption coefficient in mid-infrared (muIR) demands caution in photothermal radiometric measurements, because a constant muIR is regularly assumed in inverse analysis of the acquired signals. Adverse effects of such approximation were recently demonstrated in numerical simulations of pulsed photothermal radiometric (PPTR) temperature profiling in soft biological tissues, utilizing a general-purpose optimization code in the reconstruction process. We present here an original reconstruction code, which combines a conjugate gradient minimization algorithm with non-negativity constraint to the sought temperature vector. For the same test examples as in the former report (hyper-Gaussian temperature profiles, InSb detector with 3-5 microm acquisition band, signal-to-noise ratio SNR=300) we obtain markedly improved reconstruction results, both when using a constant value mueff and when the spectral variation muIR(lambda) is accounted for in the analysis. By comparing the results, we find that the former approach introduces observable artefacts, especially in the superficial part of the profile (z<100 microm). However, the artefacts are much less severe than previously reported and are almost absent in the case of a deeper, single-lobed test profile. We demonstrate that the observed artefacts do not result from sub-optimal selection of mueff, and that they vary with specific realizations of white noise added to the simulated signals. The same holds also for a two-lobed test profile. PMID:17264372

  4. Magnitude of shear stress on the san andreas fault: implications of a stress measurement profile at shallow depth.

    PubMed

    Zoback, M D; Roller, J C

    1979-10-26

    A profile of measurements of shear stress perpendicular to the San Andreas fault near Palmdale, California, shows a marked increase in stress with distance from the fault. The pattern suggests that shear stress on the fault increases slowly with depth and reaches a value on the order of the average stress released during earthquakes. This result has important implications for both long- and shortterm prediction of large earthquakes. PMID:17809367

  5. Fast calculation of the Voight profile absorption line of gas for the atmospheric transmission function determination

    NASA Astrophysics Data System (ADS)

    Chayanova, Eleonora A.; Ivanovsky, A. I.; Borisov, Yury A.; Glazkov, V. N.; Bankova, T. V.

    2004-01-01

    A fast method is offered for calculation of Voight spectral absorption line contour. A line profile is represented by a sum of terms of an absolutely converging series, containing undimensioned parameters a and b, connected with a property of the absorbing molecule, atmospheric temperature and pressure. The value b changes in a large limit from zero at the line center to 1000 and more at far wing of the line. The value a, describing a ratio of the Lorenz and Doppler effects, changes from a value ~5 near the surface of the Earth to 10-5 in the stratosphere. Twenty terms of series ensure the high accuracy of the approximation for values b ranging from 0 to 5. The deviation from accurate Voight contour formula is less than 4*10-4 or 0.04%. However, a large b value implies increase the number of terms, and the computing time increases accordingly. Numerical integration of Voight formula by Gauss-Hermite quadrature is simple, fast and accurate calculation for a value b> 5. In this case the deviation from accurate Voight formula is less than 2*10-5 or 0.002%. Using the proposed approximation of the Voight profile line, the atmospheric transmission function was computed for the path Sun- satellite represented as a net of tangent heights relative to the Earth"s surface up to 100 km with 1 km step. The computation method involves 29 spectral channels of the water absorption region (933-959 nm) and 14 channels of the molecular oxygen absorption region (758-771 nm). The computations were performed for certain profiles of H2O, O2, temperature and pressure. The computations results were compared with experimental data.

  6. Laser ablation of titanium nitride coated on silicon wafer substrate for depth profiling using ICP-MS

    NASA Astrophysics Data System (ADS)

    Lee, Jin Sook; Lim, H. B.

    2015-02-01

    Depth profiling of titanium nitride coated on silicon substrate at a thickness of 1 μm as a diffusion barrier for semiconductor application was studied using laser ablation (LA)-ICP-MS. The ablated particles and craters were characterized by SEM, TEM and a surface mapping microscope. Several unique characteristics were observed in this work. Although the laser beam had a short wavelength of 213 nm with flat energy, the ablated craters showed an inverse triangular shape, rather than a rectangular shape, with severe thermal degradation at the brink. In addition, the crater shape and depth were strongly dependent on the structure and thermal properties of the target. Since the TiN had a columnar structure with lower thermal conductivity and a higher melting point, it showed clear craters with less thermal degradation compared to Si substrate. The average rate of depth profiling was 40 nm per pulse. In addition, the repetition rate of the laser also significantly influenced the shape and depth of the craters. A low repetition rate produced deep craters due to high residual stress and providing sufficient time for energy concentration and heat dissipation, indicating that the repetition rate should be optimized for each material.

  7. Constraining Black Carbon Aerosol over Asia using OMI Aerosol Absorption Optical Depth and the Adjoint of GEOS-Chem

    NASA Technical Reports Server (NTRS)

    Zhang, Li; Henze, David K.; Grell, Georg A.; Carmichael. Gregory R.; Bousserez, Nicolas; Zhang, Qiang; Torres, Omar; Ahn, Changwoo; Lu, Zifeng; Cao, Junji; Mao, Yuhao

    2015-01-01

    Accurate estimates of the emissions and distribution of black carbon (BC) in the region referred to here as Southeastern Asia (70degE-l50degE, 11degS-55degN) are critical to studies of the atmospheric environment and climate change. Analysis of modeled BC concentrations compared to in situ observations indicates levels are underestimated over most of Southeast Asia when using any of four different emission inventories. We thus attempt to reduce uncertainties in BC emissions and improve BC model simulations by developing top-down, spatially resolved, estimates of BC emissions through assimilation of OMI observations of aerosol absorption optical depth (AAOD) with the GEOS-Chem model and its adjoint for April and October of 2006. Overwhelming enhancements, up to 500%, in anthropogenic BC emissions are shown after optimization over broad areas of Southeast Asia in April. In October, the optimization of anthropogenic emissions yields a slight reduction (1-5%) over India and parts of southern China, while emissions increase by 10-50% over eastern China. Observational data from in situ measurements and AERONET observations are used to evaluate the BC inversions and assess the bias between OMI and AERONET AAOD. Low biases in BC concentrations are improved or corrected in most eastern and central sites over China after optimization, while the constrained model still underestimates concentrations in Indian sites in both April and October, possibly as a. consequence of low prior emissions. Model resolution errors may contribute up to a factor of 2.5 to the underestimate of surface BC concentrations over northern India. We also compare the optimized results using different anthropogenic emission inventories and discuss the sensitivity of top-down constraints on anthropogenic emissions with respect to biomass burning emissions. In addition, the impacts of brown carbon, the formulation of the observation operator, and different a priori constraints on the optimization are

  8. SEM Technique for Depth Profiling the Morphology of Diblock Copolymer Thin Films

    NASA Astrophysics Data System (ADS)

    Harrison, Christopher; Park, Miri; Chaikin, Paul; Register, Richard; Adamson, Doug

    1996-03-01

    We present a novel technique which allows the investigation of thin film diblock copolymer microphase morphology on a variety of substrates and at different film depths. Using a high resolution, low voltage Scanning Electron Microscope (SEM), we examined the topology and underlying morphology of styrene-butadiene diblock copolymer films. In order to enhance the contrast between the styrene and butadiene regions, we stained the butadiene with osmium tetraoxide. The internal morphology of the diblock copolymer film was exposed by using a non-selective fluorine-based reactive ion etching (RIE) technique. By controlling the depth of the RIE, we can effectively peel off one monolayer at a time. By alternating between RIE and SEM, we can examine the diblock copolymer film morphology at different depths. We also investigated the relationship between island formation and internal polymer microstructure. This work was supported by the NSF under DMR 9400362.

  9. Thermal conductivity versus depth profiling of inhomogeneous materials using the hot disc technique

    NASA Astrophysics Data System (ADS)

    Sizov, A.; Cederkrantz, D.; Salmi, L.; Rosén, A.; Jacobson, L.; Gustafsson, S. E.; Gustavsson, M.

    2016-07-01

    Transient measurements of thermal conductivity are performed with hot disc sensors on samples having a thermal conductivity variation adjacent to the sample surface. A modified computational approach is introduced, which provides a method of connecting the time-variable to a corresponding depth-position. This allows highly approximate - yet reproducible - estimations of the thermal conductivity vs. depth. Tests are made on samples incorporating different degrees of sharp structural defects at a certain depth position inside a sample. The proposed methodology opens up new possibilities to perform non-destructive testing; for instance, verifying thermal conductivity homogeneity in a sample, or estimating the thickness of a deviating zone near the sample surface (such as a skin tumor), or testing for presence of other defects.

  10. Thermal conductivity versus depth profiling of inhomogeneous materials using the hot disc technique.

    PubMed

    Sizov, A; Cederkrantz, D; Salmi, L; Rosén, A; Jacobson, L; Gustafsson, S E; Gustavsson, M

    2016-07-01

    Transient measurements of thermal conductivity are performed with hot disc sensors on samples having a thermal conductivity variation adjacent to the sample surface. A modified computational approach is introduced, which provides a method of connecting the time-variable to a corresponding depth-position. This allows highly approximate-yet reproducible-estimations of the thermal conductivity vs. depth. Tests are made on samples incorporating different degrees of sharp structural defects at a certain depth position inside a sample. The proposed methodology opens up new possibilities to perform non-destructive testing; for instance, verifying thermal conductivity homogeneity in a sample, or estimating the thickness of a deviating zone near the sample surface (such as a skin tumor), or testing for presence of other defects. PMID:27475584

  11. Evaluating the Impact of Sequencing Depth on Transcriptome Profiling in Human Adipose

    PubMed Central

    Liu, Yichuan; Ferguson, Jane F.; Xue, Chenyi; Silverman, Ian M.; Gregory, Brian

    2013-01-01

    Recent advances in RNA sequencing (RNA-Seq) have enabled the discovery of novel transcriptomic variations that are not possible with traditional microarray-based methods. Tissue and cell specific transcriptome changes during pathophysiological stress in disease cases versus controls and in response to therapies are of particular interest to investigators studying cardiometabolic diseases. Thus, knowledge on the relationships between sequencing depth and detection of transcriptomic variation is needed for designing RNA-Seq experiments and for interpreting results of analyses. Using deeply sequenced Illumina HiSeq 2000 101 bp paired-end RNA-Seq data derived from adipose of a healthy individual before and after systemic administration of endotoxin (LPS), we investigated the sequencing depths needed for studies of gene expression and alternative splicing (AS). In order to detect expressed genes and AS events, we found that ∼100 to 150 million (M) filtered reads were needed. However, the requirement on sequencing depth for the detection of LPS modulated differential expression (DE) and differential alternative splicing (DAS) was much higher. To detect 80% of events, ∼300 M filtered reads were needed for DE analysis whereas at least 400 M filtered reads were necessary for detecting DAS. Although the majority of expressed genes and AS events can be detected with modest sequencing depths (∼100 M filtered reads), the estimated gene expression levels and exon/intron inclusion levels were less accurate. We report the first study that evaluates the relationship between RNA-Seq depth and the ability to detect DE and DAS in human adipose. Our results suggest that a much higher sequencing depth is needed to reliably identify DAS events than for DE genes. PMID:23826166

  12. XPS depth profiling of an ultrathin bioorganic film with an argon gas cluster ion beam.

    PubMed

    Dietrich, Paul M; Nietzold, Carolin; Weise, Matthias; Unger, Wolfgang E S; Alnabulsi, Saad; Moulder, John

    2016-01-01

    The growing interest in artificial bioorganic interfaces as a platform for applications in emerging areas as personalized medicine, clinical diagnostics, biosensing, biofilms, prevention of biofouling, and other fields of bioengineering is the origin of a need for in detail multitechnique characterizations of such layers and interfaces. The in-depth analysis of biointerfaces is of special interest as the properties of functional bioorganic coatings can be dramatically affected by in-depth variations of composition. In worst cases, the functionality of a device produced using such coatings can be substantially reduced or even fully lost. PMID:27137780

  13. Voigt profile introduces optical depth dependent systematic errors - Detected in high resolution laboratory spectra of water

    NASA Astrophysics Data System (ADS)

    Birk, Manfred; Wagner, Georg

    2016-02-01

    The Voigt profile commonly used in radiative transfer modeling of Earth's and planets' atmospheres for remote sensing/climate modeling produces systematic errors so far not accounted for. Saturated lines are systematically too narrow when calculated from pressure broadening parameters based on the analysis of laboratory data with the Voigt profile. This is caused by line narrowing effects leading to systematically too small fitted broadening parameters when applying the Voigt profile. These effective values are still valid to model non-saturated lines with sufficient accuracy. Saturated lines dominated by the wings of the line profile are sufficiently accurately modeled with a Voigt profile with the correct broadening parameters and are thus systematically too narrow when calculated with the effective values. The systematic error was quantified by mid infrared laboratory spectroscopy of the water ν2 fundamental. Correct Voigt profile based pressure broadening parameters for saturated lines were 3-4% larger than the effective ones in the spectroscopic database. Impacts on remote sensing and climate modeling are expected. Combination of saturated and non-saturated lines in the spectroscopic analysis will quantify line narrowing with unprecedented precision.

  14. [Depth Profiles of Methane Oxidation Kinetics and the Related Methanotrophic Community in a Simulated Landfill Cover].

    PubMed

    Xing, Zhi-lin; Zhao, Tian-tao; Gao, Yan-hui; He, Zhi; Yang, Xu; Peng, Xu-ya

    2015-11-01

    Simulated landfill cover with real time online monitoring system was developed using cover soils. Then the system started and the concentrations of bio-gas in various depths were continuously monitored, and it was found that the system ran continually and stably after 2-3 h when methane flux changed. After that, the relationship between regularity of methane oxidation and methane flux in landfill cover was analyzed. The results indicated that concentration of oxygen decreased with increasing methane flux when the depth was deeper than 20 cm, and no obvious correlation between oxygen concentration in landfill cover surface and methane flux, however, methane oxidation rate showed positive correlation with methane flux in various depths (range of R2 was 0.851-0.999). Kinetics of CH4 oxidation in landfill cover was fitted by CH4 -O2 dual-substrate model (range of R2 was 0.902-0.955), the half-saturation constant K(m) increasing with depth was 0.157-0.729 in dynamic condition. Finally, methanotrophs community structure in original cover soil sample and that in simulated landfill cover were investigated by high-throughout sequencing technology, and the statistics indicated that the abundance and species of methanotrophs in simulated landfill cover significantly increased compared with those in original cover soil sample, and type I methanotrophs including Methylobacter and Methylophilaceae and type II methanotrophs Methylocystis were dominant species. PMID:26911022

  15. Depth profile of persistent and emerging organic pollutants upstream of the Three Gorges Dam gathered in 2012/2013.

    PubMed

    Deyerling, Dominik; Wang, Jingxian; Bi, Yonghong; Peng, Chengrong; Pfister, Gerd; Henkelmann, Bernhard; Schramm, Karl-Werner

    2016-03-01

    Persistent and emerging organic pollutants were sampled in September 2012 and 2013 at a sampling site in front of the Three Gorges Dam near Maoping (China) in a water depth between 11 and 61 m to generate a depth profile of analytes. A novel compact water sampling system with self-packed glass cartridges was employed for the on-site enrichment of approximately 300 L of water per sample to enable the detection of low analytes levels in the picogram per liter-scale in the large water body. The overall performance of the sampling system was acceptable for the qualitative detection of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), perfluoroalkylic acids (PFAAs), pharmaceutical residues and polar pesticides. Strongly particle-associated analytes like PAHs and PCBs resided mainly in the glass wool filter of the sampling system, whereas all other compounds have mainly been enriched on the XAD-resin of the self-packed glass cartridges. The sampling results revealed qualitative information on the presence, depth distribution and origin of the investigated compounds. Although the depth profile of PAHs, PCBs, OCPs, and PFAAs appeared to be homogeneous, pharmaceuticals and polar pesticides were detected in distinct different patterns with water depth. Source analysis with diagnostic ratios for PAHs revealed their origin to be pyrogenic (burning of coal, wood and grass). In contrast, most PCBs and OCPs had to be regarded as legacy pollutants which have been released into the environment in former times and still remain present due to their persistence. The abundance of emerging organic pollutants could be confirmed, and their most abundant compounds could be identified as perfluorooctanoic acid, diclofenac and atrazine among investigated PFAAs, pharmaceuticals and polar pesticides, respectively. PMID:26585456

  16. Depth profile studies of ZrTiN coatings by laser ablation inductively coupled plasma mass spectrometry.

    PubMed

    Kanický, Viktor; Kuhn, Hans-Rudolf; Guenther, Detlef

    2004-09-01

    The feasibility of depth profiling was studied by using a 193-nm ArF* excimer laser ablation system (GeoLas, MicroLas, Goettingen, Germany) with a lens array-based beam homogenizer in combination with an ICP-QMS Agilent 7500. Two ablation cells (20 and 1.5 cm3) were compared at the laser repetition rate of 1 Hz, laser beam energy of 135 mJ and the carrier gas flow rate 1.5 L min(-1) He + 0.78 L min(-1) Ar. The ablation cell dimensions are important parameters for signal tailing; however, very small cell volumes (e.g. 1.5 cm3) may cause memory effects, which can be probably explained by dominant inertial losses of aerosol on cell walls with its delayed mobilization. The 20-cm3 ablation cell seems to be appropriate for depth profiling by continuous single-hole drilling. The study of the influence of the pit diameter magnitude on the waning and emerging signals under small crater depth/diameter aspect ratios, which range between 0.75 and 0.0375 for the 3-microm-thick coatings and pit diameters 4-80 microm, revealed that the steady-state signals of pure coating and pure substrate (out of interface) were obtained at crater diameters between 20 and 40 microm. Depth resolution defined by means of slopes of tangents in the layer interface region depend on the pit diameter and has an optimum value between 20 and 40 microm and gives 0.6 microm for the 20-microm pit. In-depth variation of concentration of coating constituent (Ti) was proved to be almost identical with two different laser/ICP systems. PMID:15551076

  17. The impact of absorption coefficient on polarimetric determination of Berry phase based depth resolved characterization of biomedical scattering samples: a polarized Monte Carlo investigation

    SciTech Connect

    Baba, Justin S; Koju, Vijay; John, Dwayne O

    2016-01-01

    The modulation of the state of polarization of photons due to scatter generates associated geometric phase that is being investigated as a means for decreasing the degree of uncertainty in back-projecting the paths traversed by photons detected in backscattered geometry. In our previous work, we established that polarimetrically detected Berry phase correlates with the mean photon penetration depth of the backscattered photons collected for image formation. In this work, we report on the impact of state-of-linear-polarization (SOLP) filtering on both the magnitude and population distributions of image forming detected photons as a function of the absorption coefficient of the scattering sample. The results, based on Berry phase tracking implemented Polarized Monte Carlo Code, indicate that sample absorption plays a significant role in the mean depth attained by the image forming backscattered detected photons.

  18. Pulsed HF radiowave absorption measurements at 2.1 MHZ. over Delhi under quiet and solar flare conditions and related electron density height profiles

    NASA Astrophysics Data System (ADS)

    Balachandra Swamy, A. C.

    EXTENDED ABSTRACT Pulsed HF radiowave absorption measurements at 2.1 MHZ. over Delhi under quiet and solar flare conditions and related electron density height profiles A.C.Balachandra swmay & Late C.S.G.K. Setty Absorption of radio waves in the ionosphere is of great practical importance for radio communication and navigation systems. The first attempt to measure the absolute magnitude of the radiowave absorption were made by appletion and Ratcliffe (1930) using the frequency change method for medium frequency waves reflected from the E-region. They concluded from their experiment that the main part of the attenuation occurred below the reflection level and named the absorption region, D-region of the ionosphere. One of the basic properties of the ionosphere is the absorption of high Frequency Radiowaves. HF radiowave absorption results mainly from collisions between electrons (which are set into forced oscillations by the electric field of the wave) and neutral air particles, the RF energy abstracted from the wave being converted into thermal energy. The radiowave absorption in the ionosphere depends on electron density and collision frequency. The most important absorbing regions are the D-region and the lower E-region (50-100 Km.) The regular diurnal variation of the electron density in this height range is caused mainly by the changes in the depth of penetration of solar XUV radiations with solar zenith angle under quiet solar conditions. In 1937 Dellinger J.H.identified fade outs in high frequency radio circuits as due to abnormal ionospheric absorption associated with solar flares. The onset of the fade out was usually rapid and the duration was typically tens of minutes like that of the visible flare, because of the sudden onset, the immediate effects of solar flares are known collectively as sudden Ionospheric Disturbances (STD). The phenomenon discovered by Dellinger is usually called a short Wave Fadeout(SWF). Since the SWF is due to abnormal absorption

  19. The determination of absorption cross sections and line profiles in vibrational overtone spectra with the use of intracavity absorption spectroscopy

    NASA Astrophysics Data System (ADS)

    Bettermann, H.; Kleist, E.; Kok, R.

    1993-03-01

    This contribution presents quantitative absorption data concerning the 7 th CH overtone stretching vibrations of n-hexane and of methylcyclopentane. The transitions are adapted to Lorentzian and Gaussian line shapes. The bank shape analyses yield the spectral positions, absorption cross sections and linewidths of the investigated transitions.

  20. Depth profiling using total reflection X-ray fluorescence spectrometry alone and in combination with ion beam sputtering

    NASA Astrophysics Data System (ADS)

    Schwenke, H.; Knoth, J.; Günther, R.; Wiener, G.; Bormann, R.

    1997-07-01

    The capability of total reflection X-ray fluorescence spectrometry (TXRF) for depth profiling is examined by means of selected examples including organometallic layers, an implantation profile of arsenic in silicon and a layered nickel/cobalt structure. For structures without density differences that are deeper than 20 nm or so, and also for buried layers and for the examination of sharp interfaces, which require the highest resolution, two different combinations of ion beam sputtering with TXRF have been employed. A microsectioning technique was investigated in which samples were etched to a bevel shape and subsequently scanned by TXRF. A depth resolution of 2.5 nm was obtained. Alternatively, the so called "transfer technique" was investigated. This involves surface atoms being sputtered by an ion beam and immediately deposited on a silicon wafer rotated behind a slit which is moved in step with the sputter progress. Subsequently, the wafer is scanned by TXRF. Using this technique, the width of a coherent Ti/Al interface within a layered structure was measured to be 1.4 nm. The depth resolutions of the "microsectioning" and the "transfer" techniques are compared with data from RBS, XPS, SIMS and SNMS.

  1. Surface analysis and depth profiling of corrosion products formed in lead pipes used to supply low alkalinity drinking water.

    PubMed

    Davidson, C M; Peters, N J; Britton, A; Brady, L; Gardiner, P H E; Lewis, B D

    2004-01-01

    Modern analytical techniques have been applied to investigate the nature of lead pipe corrosion products formed in pH adjusted, orthophosphate-treated, low alkalinity water, under supply conditions. Depth profiling and surface analysis have been carried out on pipe samples obtained from the water distribution system in Glasgow, Scotland, UK. X-ray diffraction spectrometry identified basic lead carbonate, lead oxide and lead phosphate as the principal components. Scanning electron microscopy/energy-dispersive x-ray spectrometry revealed the crystalline structure within the corrosion product and also showed spatial correlations existed between calcium, iron, lead, oxygen and phosphorus. Elemental profiling, conducted by means of secondary ion mass spectrometry (SIMS) and secondary neutrals mass spectrometry (SNMS) indicated that the corrosion product was not uniform with depth. However, no clear stratification was apparent. Indeed, counts obtained for carbonate, phosphate and oxide were well correlated within the depth range probed by SIMS. SNMS showed relationships existed between carbon, calcium, iron, and phosphorus within the bulk of the scale, as well as at the surface. SIMS imaging confirmed the relationship between calcium and lead and suggested there might also be an association between chloride and phosphorus. PMID:14982163

  2. Depth profile of a time-reversal focus in an elastic solid

    SciTech Connect

    Remillieux, Marcel C.; Anderson, Brian E.; Ulrich, T. J.; Le Bas, Pierre -Yves; Payan, Cedric

    2015-04-01

    The out-of-plane velocity component is focused on the flat surface of an isotropic solid sample using the principle of time reversal. This experiment is often reproduced in the context of nondestructive testing for imaging features near the surface of the sample. However, it is not clear how deep the focus extends into the bulk of the sample and what its profile is. In this paper, this question is answered using both numerical simulations and experimental data. The profiles of the foci are expressed in terms of the wavelengths of the dominant waves, based on the interpretation of the Lamb’s problem and the use of the diffraction limit.

  3. Be-10 and Cl-36 depth profiles in an Apollo 15 drill core

    NASA Technical Reports Server (NTRS)

    Nishiizumi, K.; Arnold, J. R.; Elmore, D.; Ma, X. Z.

    1984-01-01

    The present study of galactic cosmic ray production profiles by means of tandem accelerator mass spectrometry has measured cosmic ray-produced Be-10 and Cl-36, whose half-attenuation lengths are respectively calculated to be 120 and 132 g/sq cm. The measured half-attenuation lengths for Be-10 are noted to be slightly longer than predicted by the Reedy-Arnold (1972) theoretical model. Secondary thermal neutron production from Cl-35 is invoked as an explanation for the flatter and deeper maximum seen in the Cl-36 profile.

  4. Self-consistent depth profiling and imaging of GaN-based transistors using ion microbeams

    NASA Astrophysics Data System (ADS)

    Redondo-Cubero, A.; Corregidor, V.; Vázquez, L.; Alves, L. C.

    2015-04-01

    Using an ion microprobe, a comprehensive lateral and in-depth characterization of a single GaN-based high electron mobility transistor is carried out by means of Rutherford backscattering spectrometry (RBS) in combination with particle induced X-ray emission (PIXE). Elemental distribution was obtained for every individual section of the device (wafer, gate and source contact), identifying the basic constituents of the transistor (including the detection of the passivant layer) and checking its homogeneity. A self-consistent analysis of each individual regions of the transistor was carried out with a simultaneous fit of RBS and PIXE spectra with two different beam conditions. Following this approach, the quantification of the atomic content and the layer thicknesses was successfully achieved overcoming the mass-depth ambiguity of certain elements.

  5. A search for thermal excursions from ancient extraterrestrial impacts using Hadean zircon Ti-U-Th-Pb depth profiles.

    PubMed

    Abbott, Sunshine S; Harrison, T Mark; Schmitt, Axel K; Mojzsis, Stephen J

    2012-08-21

    Few terrestrial localities preserve more than a trace lithic record prior to ca. 3.8 Ga greatly limiting our understanding of the first 700 Ma of Earth history, a period inferred to have included a spike in the bolide flux to the inner solar system at ca. 3.85-3.95 Ga (the Late Heavy Bombardment, LHB). An accessible record of this era may be found in Hadean detrital zircons from the Jack Hills, Western Australia, in the form of μm-scale epitaxial overgrowths. By comparing crystallization temperatures of pre-3.8 Ga zircon overgrowths to the archive of zircon temperature spectra, it should, in principle, be possible to identify a distinctive impact signature. We have developed Ti-U-Th-Pb ion microprobe depth profiling to obtain age and temperature information within these zircon overgrowths and undertaken a feasibility study of its possible use in identifying impact events. Of eight grains profiled in this fashion, four have overgrowths of LHB-era age. Age vs. temperature profiles reveal a period between ca. 3.85-3.95 Ga (i.e., LHB era) characterized by significantly higher temperatures (approximately 840-875 °C) than do older or younger zircons or zircon domains (approximately 630-750 °C). However, temperatures approaching 900 °C can result in Pb isotopic exchange rendering interpretation of these profiles nonunique. Coupled age-temperature depth profiling shows promise in this role, and the preliminary data we report could represent the first terrestrial evidence for impact-related heating during the LHB. PMID:22869711

  6. A search for thermal excursions from ancient extraterrestrial impacts using Hadean zircon Ti-U-Th-Pb depth profiles

    PubMed Central

    Abbott, Sunshine S.; Harrison, T. Mark; Schmitt, Axel K.; Mojzsis, Stephen J.

    2012-01-01

    Few terrestrial localities preserve more than a trace lithic record prior to ca. 3.8 Ga greatly limiting our understanding of the first 700 Ma of Earth history, a period inferred to have included a spike in the bolide flux to the inner solar system at ca. 3.85–3.95 Ga (the Late Heavy Bombardment, LHB). An accessible record of this era may be found in Hadean detrital zircons from the Jack Hills, Western Australia, in the form of μm-scale epitaxial overgrowths. By comparing crystallization temperatures of pre-3.8 Ga zircon overgrowths to the archive of zircon temperature spectra, it should, in principle, be possible to identify a distinctive impact signature. We have developed Ti-U-Th-Pb ion microprobe depth profiling to obtain age and temperature information within these zircon overgrowths and undertaken a feasibility study of its possible use in identifying impact events. Of eight grains profiled in this fashion, four have overgrowths of LHB-era age. Age vs. temperature profiles reveal a period between ca. 3.85–3.95 Ga (i.e., LHB era) characterized by significantly higher temperatures (approximately 840–875 °C) than do older or younger zircons or zircon domains (approximately 630–750 °C). However, temperatures approaching 900 °C can result in Pb isotopic exchange rendering interpretation of these profiles nonunique. Coupled age-temperature depth profiling shows promise in this role, and the preliminary data we report could represent the first terrestrial evidence for impact-related heating during the LHB. PMID:22869711

  7. Evaluation of tropospheric water vapor profiling using eye-safe, infrared differential absorption lidar

    SciTech Connect

    Rye, B.J. |; Machol, J.L.; Grund, C.J.; Hardesty, R.M.

    1996-05-14

    Continuous, high quality profiles of water vapor, free of systematic bias, and of moderate temporal and spatial resolution are fundamental to the success of the ARM CART program. In addition, these should be acquired over long periods at low operational and maintenance cost. The development and verification of realistic climate model parameterizations for clouds and net radiation balance, and the correction of other CART site sensor observations for interferences due to the presence of water vapor are critically dependent on water vapor profile measurements. To date, application of profiles have been limited by vertical resolution and uniqueness and high operating cost, or diminished daytime performance, lack of eye-safety, and high maintenance cost. Recent developments in infrared laser and detector technology make possible compact IR differential absorption lidar (DIAL) systems at eye-safe wavelengths. In the studies reported here, we develop DIAL system performance models and examine the potential of solving some of the shortcomings of previous methods using parameters representative of current technologies. These simulations are also applied to determine the strengths and weaknesses unique to the DIAL method for this application.

  8. Quantitative X-ray photoelectron spectroscopy-based depth profiling of bioleached arsenopyrite surface by Acidithiobacillus ferrooxidans

    NASA Astrophysics Data System (ADS)

    Zhu, Tingting; Lu, Xiancai; Liu, Huan; Li, Juan; Zhu, Xiangyu; Lu, Jianjun; Wang, Rucheng

    2014-02-01

    In supergene environments, microbial activities significantly enhance sulfide oxidation and result in the release of heavy metals, causing serious contamination of soils and waters. As the most commonly encountered arsenic mineral in nature, arsenopyrite (FeAsS) accounts for arsenic contaminants in various environments. In order to investigate the geochemical behavior of arsenic during microbial oxidation of arsenopyrite, (2 3 0) surfaces of arsenopyrite slices were characterized after acidic (pH 2.00) and oxidative decomposition with or without an acidophilic microorganism Acidithiobacillus ferrooxidans. The morphology as well as chemical and elemental depth profiles of the oxidized arsenopyrite surface were investigated by scanning electron microscopy and X-ray photoelectron spectroscopy. With the mediation of bacteria, cell-shaped and acicular pits were observed on the reacted arsenopyrite surface, and the concentration of released arsenic species in solution was 50 times as high as that of the abiotic reaction after 10 days reaction. Fine-scale XPS depth profiles of the reacted arsenopyrite surfaces after both microbial and abiotic oxidation provided insights into the changes in chemical states of the elements in arsenopyrite surface layers. Within the 450 nm surface layer of abiotically oxidized arsenopyrite, Fe(III)-oxides appeared and gradually increased towards the surface, and detectable sulfite and monovalent arsenic appeared above 50 nm. In comparison, higher contents of ferric sulfate, sulfite, and arsenite were found in the surface layer of approximately 3 μm of the microbially oxidized arsenopyrite. Intermediates, such as Fe(III)-AsS and S0, were detectable in the presence of bacteria. Changes of oxidative species derived from XPS depth profiles show the oxidation sequence is Fe > As = S in abiotic oxidation, and Fe > S > As in microbial oxidation. Based on these results, a possible reaction path of microbial oxidation was proposed in a concept model.

  9. The dark side of the hyporheic zone: Depth profiles of nitrogen and its processing in stream sediments

    USGS Publications Warehouse

    Stelzer, R.S.; Bartsch, L.A.; Richardson, W.B.; Strauss, E.A.

    2011-01-01

    1.Although it is well known that sediments can be hot spots for nitrogen transformation in streams, many previous studies have confined measurements of denitrification and nitrate retention to shallow sediments (<5cm deep). We determined the extent of nitrate processing in deeper sediments of a sand plains stream (Emmons Creek) by measuring denitrification in core sections to a depth of 25cm and by assessing vertical nitrate profiles, with peepers and piezometers, to a depth of 70cm. 2.Denitrification rates of sediment slurries based on acetylene block were higher in shallower core sections. However, core sections deeper than 5cm accounted for 68% of the mean depth-integrated denitrification rate. 3.Vertical hydraulic gradient and vertical profiles of pore water chloride concentration suggested that deep ground water upwelled through shallow sediments before discharging to the stream channel. The results of a two-source mixing model based on chloride concentrations suggested that the hyporheic zone was very shallow (<5cm) in Emmons Creek. 4.Vertical profiles showed that nitrate concentration in shallow ground water was about 10-60% of the nitrate concentration of deep ground water. The mean nitrate concentrations of deep and shallow ground water were 2.17 and 0.73mgNO3-NL-1, respectively. 5.Deep ground water tended to be oxic (6.9mgO2L-1) but approached anoxia (0.8mgO2L-1) after passing through shallow, organic carbon-rich sediments, which suggests that the decline in the nitrate concentrations of upwelling ground water was because of denitrification. 6.Collectively, our results suggest that there is substantial nitrate removal occurring in deep sediments, below the hyporheic zone, in Emmons Creek. Our findings suggest that not accounting for nitrate removal in deep sediments could lead to underestimates of nitrogen processing in streams and catchments. ?? 2011 Blackwell Publishing Ltd.

  10. Depth profile of a time-reversal focus in an elastic solid

    DOE PAGESBeta

    Remillieux, Marcel C.; Anderson, Brian E.; Ulrich, T. J.; Le Bas, Pierre -Yves; Payan, Cedric

    2015-04-01

    The out-of-plane velocity component is focused on the flat surface of an isotropic solid sample using the principle of time reversal. This experiment is often reproduced in the context of nondestructive testing for imaging features near the surface of the sample. However, it is not clear how deep the focus extends into the bulk of the sample and what its profile is. In this paper, this question is answered using both numerical simulations and experimental data. The profiles of the foci are expressed in terms of the wavelengths of the dominant waves, based on the interpretation of the Lamb’s problemmore » and the use of the diffraction limit.« less

  11. Depth profiling of ion implanted materials with skewed doping distributions using Fourier transform infrared spectroscopy

    NASA Astrophysics Data System (ADS)

    Katsidis, Charalambos C.

    2008-01-01

    The applicability of a general transfer-matrix method for optical analysis of multilayers reported earlier [Katsidis and Siapkas, Appl. Opt. 41, 3978 (2002)] is being extended so as to simulate asymmetric implantation doping profiles using distributions with four moments. The sensitivity of infrared reflectance spectra regarding the variation of the first four moments of a Pearson free carrier distribution is demonstrated. Experimental data of 1.5 MeV as well as 2.5 MeV As implantation into p-Si followed by annealing at 1100 °C are presented, suggesting the need to use two joined Pearson IV distribution segments in the simulation of annealed profiles. A twin peak observed in the 1.5 MeV case is confirmed by Rutherford backscattering analysis.

  12. Depth profiling of photothermal compound concentrations using phase sensitive optical coherence tomography

    PubMed Central

    Guan, Guangying; Reif, Roberto; Huang, Zhihong; Wang, Ruikang K.

    2011-01-01

    A model that describes the concentration of photothermal (light-to-heat converters) compounds as a function of depth in a turbid medium is developed. The system consists of a pump laser (808 nm modulated at 400 Hz), which heats a photothermal compound, and a phase sensitive spectral domain optical coherence tomography system, which detects the changes in the optical path length of the sample induced by the temperature increase. The model is theoretically derived and the coefficients are empirically determined using solid homogeneous gel phantoms. The model is validated by reconstructing the concentration of a photothermal compound in thick single and double layer solid phantoms. PMID:22191920

  13. New Electrodeposition Technique for Controlling Depth Profile of CuInSe2 Thin Films for Solar Cell Application

    NASA Astrophysics Data System (ADS)

    Nakamura, Sigeyuki

    2005-04-01

    It is known that the efficiency of CuInSe2 (CIS)-based solar cells can be improved using a CIS layer with a composition that can be modulated to be In-rich near the pn junction interface. In this work, a new electrodeposition technique for preparing CIS thin films with a controlled composition depth profile was developed. CIS thin films having a bilayer structure, that is, with the Cu-rich and In-rich layers, were successfully deposited from one electrolyte only by changing the substrate potential during electrodeposition.

  14. A summary report on the search for current technologies and developers to develop depth profiling/physical parameter end effectors

    SciTech Connect

    Nguyen, Q.H.

    1994-09-12

    This report documents the search strategies and results for available technologies and developers to develop tank waste depth profiling/physical parameter sensors. Sources searched include worldwide research reports, technical papers, journals, private industries, and work at Westinghouse Hanford Company (WHC) at Richland site. Tank waste physical parameters of interest are: abrasiveness, compressive strength, corrosiveness, density, pH, particle size/shape, porosity, radiation, settling velocity, shear strength, shear wave velocity, tensile strength, temperature, viscosity, and viscoelasticity. A list of related articles or sources for each physical parameters is provided.

  15. Assessment of Zooplankton Community Composition along a Depth Profile in the Central Red Sea

    PubMed Central

    Pearman, John K.; Irigoien, Xabier

    2015-01-01

    The composition of zooplankton in the water column has received limited attention in the main body of the Red Sea and this study investigates the change in the community both spatially and temporally across 11 stations in the central Red Sea. Using molecular methods to target the v9 region of the 18S rRNA gene a total of approximately 11.5 million reads were sequenced resulting in 2528 operational taxonomic units (OTUs) at 97% similarity. The phylum Arthropoda dominated in terms of reads accounting for on average 86.2% and 65.3% for neuston nets and vertical multinets respectively. A reduction in the number of OTUs was noticed with depth for both total metazoa and Maxillopoda whilst there was also a significant change in the composition of the Maxillopoda community. The genus Corycaeus had a higher proportion of reads in the epipelagic zone with Pleuromamma becoming increasingly dominant with depth. No significant difference was observed in the community between night and day sampling however there was a significant difference in the zooplankton community between two sampling periods separated by 10 days. PMID:26186220

  16. The XPS depth profiling and tribological characterization of ion-plated gold on various metals

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Spalvins, T.; Buckley, D. H.

    1983-01-01

    Friction properties were measured with a gold film; the graded interface between gold and nickel substrate; and the nickel substrate. All sliding was conducted against hard silicon carbide pins in two processes. In the adhesive process, friction arises primarily from adhesion between sliding surfaces. In the abrasion process, friction occurs as a result of the hard pin sliding against the film, indenting into it, and plowing a series of grooves. Copper and 440 C stainless steel substrates were also used. Results indicate that the friction related to both adhesion and abrasion is influenced by coating depth. The trends in friction behavior as a function of film depth are, however, just the opposite. The graded interface exhibited the highest adhesion and friction, while the graded interface resulted in the lowest abrasion and friction. The coefficient of friction due to abrasion is inversely related to the hardness. The greater the hardness of the surface, the lower is the abrasion and friction. The microhardness in the graded interface exhibited the highest hardness due to an alloy hardening effect. Almost no graded interface between the vapor-deposited gold film and the substrates was detected.

  17. Characterizing the dissolution profiles of supersaturable salts, cocrystals, and solvates to enhance in vivo oral absorption.

    PubMed

    Hisada, Nozomi; Takano, Ryusuke; Takata, Noriyuki; Shiraki, Koji; Ueto, Takamitsu; Tanida, Satoshi; Kataoka, Makoto; Yamashita, Shinji

    2016-06-01

    The purposes of this study were to elucidate the type-specific characteristics of salt, cocrystal, and solvate formulations upon dissolution and precipitation, and to clarify their effect on enhancing oral absorption. Several types of solid formulations (dantrolene sodium salt [DAN-NA], pioglitazone hydrochloride salt [PIO-HCL], megestrol acetate saccharin cocrystal [MEG-SA], and an in-house compound ZR ethanolate [ZR-ETH]) that induce supersaturation of BCS class II drugs were compared to their crystalline free forms. An in vitro miniscale dissolution test in biorelevant media was used to characterize their dissolution profiles and residue forms. Both salts (DAN-NA and PIO-HCL) rapidly reached the maximum concentration within 5min, whereas the cocrystal (MEG-SA) did so slowly. After the maximum concentration had been reached, the dissolved concentrations of DAN-NA, PIO-HCL, and MEG-SA decreased, but that of ZR-ETH did not. Time-dependent XRPD analysis revealed that the initial solid state of each salt dissolved within 5min, whereas the cocrystal remained for more than 10min, and the solvate remained for 4h. It also revealed that PIO-HCL and MEG-SA precipitated to the stable free form, while DAN-NA precipitated to the metastable form, which maintains a higher concentration than the stable free form continuously. In vivo absorption in beagle dogs was also examined. The plasma AUC of DAN-NA, MEG-SA, and ZR-ETH was respectively 1.5-, 2.1-, and 11-fold more than each free form. On the other hand, the absorption of PIO-HCL was not enhanced compared with its free form. The results in the present study clarified that not only the precipitation rate and the form of precipitation but also the retention of the initial solid state in the absorption process contribute to enhancing the in vivo absorption of Class II drugs from solid formulations such as salts, solvates, and cocrystals. PMID:27060622

  18. In situ 14C depth profile of subsurface vein quartz samples from Macraes Flat New Zealand

    NASA Astrophysics Data System (ADS)

    Kim, K. J.; Lal, D.; Englert, P. A. J.; Southon, J.

    2007-06-01

    We present results of measurements of cosmogenic in situ 14C produced in a quartz vein from Macraes Flat, East Otago, New Zealand, where concentrations of in situ produced 10Be and 26Al were previously studied by Kim and Englert [Earth Planet. Sci. Lett. 223 (2004) 113]. 14C was extracted from the quartz samples up to depths of 400 g cm-2 using a low temperature wet extraction method [D. Lal, A.J.T. Jull, Nucl. Instr. and Meth. B 92 (1994) 291]. Based on the results for 10Be and 26Al, we expected that the 14C activity in the samples would be at saturation levels, in equilibrium with erosion. The surface exposure age of this site was found to be about 25 000 years using 10Be and 26Al at the surface, with a surface erosion rate of at least 10-3 cm/y [K.J. Kim, P.A.J. Englert, Earth Planet. Sci. Lett. 223 (2004) 113]. The measured 14C activities were compared with those expected from spallation of Si and O in quartz by energetic neutrons and fast muons, and from capture of negative muons in O in quartz [B. Heisinger, A.J.T. Jull, D. Lal, P. Kubik, S. Ivy-Ochs, K. Knie, E. Nolte, Earth Planet. Sci. Lett. 200 (2002) 357; B. Heisinger, D. Lal, A.J.T. Jull, P. Kubik, S. Ivy-Ochs, S. Neumaier, K. Knie, V. Lazarev, E. Nolte, Earth Planet. Sci. Lett. 200 (2002) 345]. Surprisingly, we found that the 14C activities were significantly greater than those expected, by factors of 2 3, especially in samples of depths <200 g cm-2. We suspect that the excess 14C probably resulted from capture of thermal neutrons in nitrogen present in the fluid inclusions in quartz. This study shows that great care has to be taken in measurements of in situ 14C in quartz, especially in samples exposed near sea level and greater depths, where rates of spallation produced 14C are low.

  19. Oral absorption profiles of sulfonamides in Shiba goats: a comparison among sulfadimidine, sulfadiazine and sulfanilamide.

    PubMed

    Elbadawy, Mohamed; Ishihara, Yusuke; Aboubakr, Mohamed; Sasaki, Kazuaki; Shimoda, Minoru

    2016-07-01

    The oral pharmacokinetics of three sulfonamides, sulfadimidine (pKa 7.5), sulfadiazine (pKa 6.5) and sulfanilamide (pKa 10.5), with different rates of unionization in rumen juice, were compared in Shiba goats to clarify the relationship between drug absorption profiles after their oral administration as well as their degree of unionization in the rumen. Sulfonamides were administered either into the left jugular vein or orally to five male goats at doses of 10 mg/kg body weight, using a crossover design with at least a 3-week washout period. The Tmax of sulfadimidine, sulfadiazine and sulfanilamide reached 2.0 ± 1.2, 6.0 ± 0.0, and 7.8 ± 1.6 hr, respectively, after their oral administration, and this was followed by their slow elimination due to a slow rate of drug absorption from the gastrointestinal tract. The MAT and t1/2ka of sulfadiazine (13.2 ± 2.0 and 10.9 ± 1.08 hr) were significantly longer than those of sulfanilamide (9.09 ± 1.67 and 7.46 ± 1.70 hr) and sulfadimidine (7.52 ± 0.85 and 5.17 ± 0.66 hr). These results suggest that the absorption rates of highly unionized drugs (such as sulfanilamide and sulfadimidine) from the forestomach of goats may be markedly higher than less unionized ones (such as sulfadiazine). The mean oral bioavailability of sulfadiazine was high (83.9 ± 17.0%), whereas those of sulfadimidine and sulfanilamide were low (44.9 ± 16.4% and 49.2 ± 2.11%, respectively). PMID:27010464

  20. Oral absorption profiles of sulfonamides in Shiba goats: a comparison among sulfadimidine, sulfadiazine and sulfanilamide

    PubMed Central

    ELBADAWY, Mohamed; ISHIHARA, Yusuke; ABOUBAKR, Mohamed; SASAKI, Kazuaki; SHIMODA, Minoru

    2016-01-01

    The oral pharmacokinetics of three sulfonamides, sulfadimidine (pKa 7.5), sulfadiazine (pKa 6.5) and sulfanilamide (pKa 10.5), with different rates of unionization in rumen juice, were compared in Shiba goats to clarify the relationship between drug absorption profiles after their oral administration as well as their degree of unionization in the rumen. Sulfonamides were administered either into the left jugular vein or orally to five male goats at doses of 10 mg/kg body weight, using a crossover design with at least a 3-week washout period. The Tmax of sulfadimidine, sulfadiazine and sulfanilamide reached 2.0 ± 1.2, 6.0 ± 0.0, and 7.8 ± 1.6 hr, respectively, after their oral administration, and this was followed by their slow elimination due to a slow rate of drug absorption from the gastrointestinal tract. The MAT and t1/2ka of sulfadiazine (13.2 ± 2.0 and 10.9 ± 1.08 hr) were significantly longer than those of sulfanilamide (9.09 ± 1.67 and 7.46 ± 1.70 hr) and sulfadimidine (7.52 ± 0.85 and 5.17 ± 0.66 hr). These results suggest that the absorption rates of highly unionized drugs (such as sulfanilamide and sulfadimidine) from the forestomach of goats may be markedly higher than less unionized ones (such as sulfadiazine). The mean oral bioavailability of sulfadiazine was high (83.9 ± 17.0%), whereas those of sulfadimidine and sulfanilamide were low (44.9 ± 16.4% and 49.2 ± 2.11%, respectively). PMID:27010464

  1. Depth profiling of laser-heated chromophores in biological tissues by pulsed photothermal radiometry.

    PubMed

    Milner, T E; Goodman, D M; Tanenbaum, B S; Nelson, J S

    1995-07-01

    A solution method is proposed to the inverse problem of determining the unknown initial temperature distribution in a laser-exposed test material from measurements provided by infrared radiometry. A Fredholm integral equation of the first kind is derived that relates the temporal evolution of the infrared signal amplitude to the unknown initial temperature distribution in the exposed test material. The singular-value decomposition is used to demonstrate the severely ill-posed nature of the derived inverse problem. Three inversion methods are used to estimate solutions for the initial temperature distribution. A nonnegatively constrained conjugate-gradient algorithm using early termination is found superior to unconstrained inversion methods and is applied to image the depth of laser-heated chromophores in human skin. PMID:7608789

  2. Depth profiling of laser-heated chromophores in biological tissues by pulsed photothermal radiometry

    SciTech Connect

    Milner, T.E.; Goodman, D.M.; Tanenbaum, B.S.; Nelson, J.S.

    1995-07-01

    A solution method is proposed to the inverse problem of determining the unknown initial temperature distribution in a laser-exposed test material from measurements provided by infrared radiometry. A Fredholm integral equation of the first kind is derived that relates the temporal evolution of the infrared signal amplitude to the unknown initial temperature distribution in the exposed test material. The singular-value decomposition is used to demonstrate the severely ill-posed nature of the derived inverse problem. Three inversion methods are used to estimate solutions for the initial temperature distribution. A nonnegatively constrained conjugate-gradient algorithm using early termination is found superior to unconstrained inversion methods and is applied to image the depth of laser-heated chromophores in human skin. {ital Key} {ital words}: constrained conjugate gradients, ill-posed problem, infrared radiometry, laser surgery, nonnegative, singular-value decomposition.

  3. Clay composition and swelling potential estimation of soils using depth of absorption bands in the SWIR (1100-2500 nm) spectral domain

    NASA Astrophysics Data System (ADS)

    Dufréchou, Grégory; Granjean, Gilles; Bourguignon, Anne

    2014-05-01

    Swelling soils contain clay minerals that change volume with water content and cause extensive and expensive damage on infrastructures. Presence of clay minerals is traditionally a good estimator of soils swelling and shrinking behavior. Montmorillonite (i.e. smectite group), illite, kaolinite are the most common minerals in soils and are usually associated to high, moderate, and low swelling potential when they are present in significant amount. Characterization of swelling potential and identification of clay minerals of soils using conventional analysis are slow, expensive, and does not permit integrated measurements. SWIR (1100-2500 nm) spectral domain are characterized by significant spectral absorption bands related to clay content that can be used to recognize main clay minerals. Hyperspectral laboratory using an ASD Fieldspec Pro spectrometer provides thus a rapid and less expensive field surface sensing that permits to measure soil spectral properties. This study presents a new laboratory reflectance spectroscopy method that used depth of clay diagnostic absorption bands (1400 nm, 1900 nm, and 2200 nm) to compare natural soils to synthetic montmorillonite-illite-kaolinite mixtures. We observe in mixtures that illite, montmorillonite, and kaolinite content respectively strongly influence the depth of absorption bands at 1400 nm (D1400), 1900 nm (D1900), and 2200 nm (D2200). To attenuate or removed effects of abundance and grain size, depth of absorption bands ratios were thus used to performed (i) 3D (using D1900/D2200, D1400/D1900, and D2200/D1400 as axis), and (ii) 2D (using D1400/D1900 and D1900/D2200 as axis) diagrams of synthetic mixtures. In this case we supposed that the overall reduction or growth of depth absorption bands should be similarly affected by the abundance and grain size of materials in soil. In 3D and 2D diagrams, the mixtures define a triangular shape formed by two clay minerals as external envelop and the three clay minerals mixtures

  4. Speciation of organic phosphorus in a sediment profile of Lake Taihu. II. Molecular species and their depth attenuation.

    PubMed

    Ding, Shiming; Di, Xu; Bai, Xiuling; Yao, Shuchun; Fan, Chengxin; Zhang, Chaosheng

    2013-05-01

    The understanding of organic phosphorus (P) dynamics in sediments requires information on their species at the molecular level, but such information in sediment profiles is scarce. A sediment profile was selected from a large eutrophic lake, Lake Taihu (China), and organic P species in the sediments were detected using solution phosphorus-31 nuclear magnetic resonance spectroscopy (31P NMR) following extraction of the sediments with a mixture of 0.25 mol/L NaOH and 50 mmol/L EDTA (NaOH-EDTA) solution. The results showed that P in the NaOH-EDTA extracts was mainly composed of orthophosphate, orthophosphate monoesters, phospholipids, DNA, and pyrophosphate. Concentrations of the major organic P compound groups and pyrophosphate showed a decreasing trend with the increase of depth. Their half-life times varied from 3 to 27 years, following the order of orthophosphate monoesters > phospholipids > or = DNA > pyrophosphate. Principal component analysis revealed that the detected organic P species had binding phases similar to those of humic acid-associated organic P (NaOH-NRP(HA)), a labile organic P pool that tends to transform to recalcitrant organic P pools as the early diagenetic processes proceed. This demonstrated that the depth attenuation of the organic P species could be partly attributed to their increasing immobilization by the sediment solids, while their degradation rates should be significantly lower than what were suggested in previous studies. PMID:24218822

  5. Uranium-236 as a new oceanic tracer: A first depth profile in the Japan Sea and comparison with caesium-137

    PubMed Central

    Sakaguchi, Aya; Kadokura, Akinobu; Steier, Peter; Takahashi, Yoshio; Shizuma, Kiyoshi; Hoshi, Masaharu; Nakakuki, Tomoeki; Yamamoto, Masayoshi

    2012-01-01

    We present a feasibility study for using 236U as an oceanic circulation tracer based on depth profiles of 236U and 137Cs in the Japan/East Sea. The concentration of the predominantly anthropogenic 236U, measured with Accelerator Mass Spectrometry (AMS), decreased from (13±3)×106 atom/kg in surface water to (1.6±0.3)×106 atom/kg close to the sea floor (2800 m). The profile has a smooth trend with depth and concentration values are generally proportional to that of 137Cs for the same water samples, but with a slightly lower ratio of 137Cs/236U below 2000 m. The cumulative inventory of dissolved 236U in the water column was estimated to be (13.7±0.9)×1012 atom/m2, which is similar to the global-fallout level (17.8×1012 atom/m2) in Japan. Additional analyses of suspended solids (SS) and bottom sediments yielded negligible amounts of 236U. Our results suggest that 236U behaves as a conservative nuclide in seawater, with potential advantages over other tracers of oceanic circulation. PMID:23564965

  6. Depth Profiles of Mg, Si, and Zn Implants in GaN by Trace Element Accelerator Mass Spectrometry

    SciTech Connect

    Ravi Prasad, G.V.; Pelicon, P.; Mitchell, L.J.; McDaniel, F.D.

    2003-08-26

    GaN is one of the most promising electronic materials for applications requiring high-power, high frequencies, or high-temperatures as well as opto-electronics in the blue to ultraviolet spectral region. We have recently measured depth profiles of Mg, Si, and Zn implants in GaN substrates by the TEAMS particle counting method for both matrix and trace elements, using a gas ionization chamber. Trace Element Accelerator Mass Spectrometry (TEAMS) is a combination of Secondary Ion Mass Spectrometry (SIMS) and Accelerator Mass Spectrometry (AMS) to measure trace elements at ppb levels. Negative ions from a SIMS like source are injected into a tandem accelerator. Molecular interferences inherent with the SIMS method are eliminated in the TEAMS method. Negative ion currents are extremely low with GaN as neither gallium nor nitrogen readily forms negative ions making the depth profile measurements more difficult. The energies of the measured ions are in the range of 4-8 MeV. A careful selection of mass/charge ratios of the detected ions combined with energy-loss behavior of the ions in the ionization chamber eliminated molecular interferences.

  7. Quantitative XPS depth profiling of codeine loaded poly(l-lactic acid) films using a coronene ion sputter source.

    PubMed

    Rafati, Ali; Davies, Martyn C; Shard, Alexander G; Hutton, Simon; Mishra, Gautam; Alexander, Morgan R

    2009-08-19

    The controlled release of active pharmaceutical ingredients from polymers over prolonged periods of time is vital for the function of drug eluting stents and other drug loaded delivery devices. Characterisation of the drug distribution in polymers allows the in vitro and in vivo performance to be rationalised. We present the first X-ray photoelectron spectroscopy (XPS) depth profiling study of such a drug eluting stent system for which we employ a novel coronene ion sputter source. The rationale for this is to ascertain quantitative atomic concentration data through the thickness of flat films containing codeine and poly(l-lactic acid) (PLA) as a model of a drug loaded polymer device. A range of films of thickness of up to 96 nm are spun cast from chloroform onto Piranha cleaned silicon wafers. Ellipsometry of the films is undertaken prior to depth profiling to determine the total film thickness and provide a measure of the relative loading of drug within the PLA matrix through spectroscopic analysis. Progressive XPS analysis of the bottom of the sputter crater with sputter time indicated codeine to be depleted from the surface and segregated to the bulk of the polymer films by comparison with a uniform distribution calculated from the bulk loading. This serves to illustrate that surface depletion of drug occurs, which poses important implications for drug loaded polymer delivery systems. PMID:19427343

  8. Characterization of oxide layers on amorphous Zr-based alloys by Auger electron spectroscopy with sputter depth profiling

    NASA Astrophysics Data System (ADS)

    Baunack, S.; Mudali, U. Kamachi; Gebert, A.

    2005-09-01

    Amorphous Zr-Cu-Ni-Al-[Ti, Nb] ribbons prepared by melt spinning under argon atmosphere were subjected to electrochemical investigations. Passive films developed at potentiostatic anodic polarization in sulphuric acid solution were investigated by Auger electron spectroscopy (AES) and sputter depth profiling. Changes in the shape of the Auger peaks have been analyzed by factor analysis of the spectra obtained during depth profiling. Pronounced changes in shape and position occur for the Zr, Al, and Ti Auger transitions, but not for Cu and Ni. At least three different peak shapes for O(KVV) were found and attributed to different oxygen binding states. The alloy composition has no significant effect on the thickness and composition of the oxide layer. In multi-element alloys preferential sputtering is a common phenomenon. In the steady state of sputtering, a significant depletion in Cu is found. At the oxide/metal interface, a distinct enrichment of copper is found for all alloys and treatments. The degree of this Cu enrichment depends on the pretreatment. It is higher for the electrochemically-passivated samples than for samples with oxide layers grown during melt spinning.

  9. Near-Surface Shear Wave Velocity Versus Depth Profiles, VS30, and NEHRP Classifications for 27 Sites in Puerto Rico

    USGS Publications Warehouse

    Odum, Jack K.; Williams, Robert A.; Stephenson, William J.; Worley, David M.; von Hillebrandt-Andrade, Christa; Asencio, Eugenio; Irizarry, Harold; Cameron, Antonio

    2007-01-01

    In 2004 and 2005 the Puerto Rico Seismic Network (PRSN), Puerto Rico Strong Motion Program (PRSMP) and the Geology Department at the University of Puerto Rico-Mayaguez (UPRM) collaborated with the U.S. Geological Survey to study near-surface shear-wave (Vs) and compressional-wave (Vp) velocities in and around major urban areas of Puerto Rico. Using noninvasive seismic refraction-reflection profiling techniques, we acquired velocities at 27 locations. Surveyed sites were predominantly selected on the premise that they were generally representative of near-surface materials associated with the primary geologic units located within the urbanized areas of Puerto Rico. Geologic units surveyed included Cretaceous intrusive and volcaniclastic bedrock, Tertiary sedimentary and volcanic units, and Quaternary unconsolidated eolian, fluvial, beach, and lagoon deposits. From the data we developed Vs and Vp depth versus velocity columns, calculated average Vs to 30-m depth (VS30), and derived NEHRP (National Earthquake Hazards Reduction Program) site classifications for all sites except one where results did not reach 30-m depth. The distribution of estimated NEHRP classes is as follows: three class 'E' (VS30 below 180 m/s), nine class 'D' (VS30 between 180 and 360 m/s), ten class 'C' (VS30 between 360 and 760 m/s), and four class 'B' (VS30 greater than 760 m/s). Results are being used to calibrate site response at seismograph stations and in the development of regional and local shakemap models for Puerto Rico.

  10. Depth profiling of inks in authentic and counterfeit banknotes by electrospray laser desorption ionization/mass spectrometry.

    PubMed

    Kao, Yi-Ying; Cheng, Sy-Chyi; Cheng, Chu-Nian; Shiea, Jentaie

    2016-01-01

    Electrospray laser desorption ionization is an ambient ionization technique that generates neutrals via laser desorption and ionizes those neutrals in an electrospray plume and was utilized to characterize inks in different layers of copy paper and banknotes of various currencies. Depth profiling of inks was performed on overlapping color bands on copy paper by repeatedly scanning the line with a pulsed laser beam operated at a fixed energy. The molecules in the ink on a banknote were desorbed by irradiating the banknote surface with a laser beam operated at different energies, with results indicating that different ions were detected at different depths. The analysis of authentic $US100, $100 RMB and $1000 NTD banknotes indicated that ions detected in 'color-shifting' and 'typography' regions were significantly different. Additionally, the abundances of some ions dramatically changed with the depth of the aforementioned regions. This approach was used to distinguish authentic $1000 NTD banknotes from counterfeits. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26757068

  11. A Stellar Occultation Sensor Using Absorption and Refraction of Starlight for Atmospheric Profile Measurements

    NASA Astrophysics Data System (ADS)

    Morgan, F.; Yee, J.; Murphy, G.; Swartz, W.; Demajistre, R.; Vervack, R.; Morrison, D.

    2008-12-01

    The Self-Calibrating H2O and O3 Nighttime Environmental Remote Sensor (SCHOONERS) is a compact, integrated UV-IR imaging spectrograph and imager for spaceborne stellar occultation measurements, developed under the NASA Instrument Incubator Program and based on the measurement technique and retrieval demonstrated by the MSX/UVISI instrument. The imaging spectrograph, covering a spectral range between 300 and 900 nm, measures the varying absorption of starlight as a star sets through the Earth's atmosphere to determine vertical profiles of atmospheric constituents. The relative star position measured by the co-aligned imager not only provides position feedback to the active-tracking loop but also measures the star refraction angle for determining the atmospheric density and temperature profiles. The instrument has a 25-cm-diameter aperture and employs a two-axis gimbaled telescope to provide acquisition and tracking of the star. It also uses a two-axis high-precision vernier mirror to correct for spacecraft jitter and maintain the star within the field-of-view. SCHOONERS' hardware and accompanying software have been demonstrated in end-to-end laboratory tests. SCHOONERS' built-in image tracking and motion compensation mechanism, coupled with its small size and limited spacecraft resource requirements, makes it suitable for deployment on existing and future spacecraft platforms as an instrument-of-opportunity. In this paper, stellar occultation sensing technique, experiment requirements, and SCHOONERS design and expected performance will be presented.

  12. Does strip-tillage could limit the drop of yields on soils of reduced depth of profiles in loess areas?

    NASA Astrophysics Data System (ADS)

    Rejman, Jerzy; Rafalska-Przysucha, Anna; Jadzczyszyn, Jan; Rodzik, Jan

    2016-04-01

    Strip tillage restrict a tillage operation to seed rows and enables a combination of tillage, sowing and application of fertilizers during one pass of agricultural machines. The practice decreases the costs of fuel and limits the risk of water erosion by the increase of infiltration of soil water. In the studies, we put a hypothesis that strip tillage is a tool to increase the yields on soils of reduced profiles. Studies were carried out in the loess area of the Lublin Upland (Poland). The site is cultivated from the beginning of the 18th century, and strip tillage is performed from 2008. All plant residues is left after harvest in the field and mixed with the soil by disc harrow. Measurements of solum depth (Ap-BC), soil properties and parameters of plant growth were carried out in 108 points in the field of the area of 4 ha. Crops included winter wheat (2014) and maize (2015). Studies showed that the profiles of Haplic Luvisol were largely truncated or overbuilt due to erosion and moldboard plow in the past. Solum depth ranged from 0.2 to 3.6 m (mean=1.29 m, CV=64%), and soils with the non-eroded, slightly, moderately, severely, very severely eroded and depositional profiles represented 13, 32, 10, 5, 8 and 32% of total number of cores, respectively. In a result of modification of profiles, clay content ranged from 84 to 222 (145; 16%) in the layer of 0-15 cm, whereas SOC concentration remained on relatively low level and ranged from 4.3 to 16.8 g/kg (9.1; 21.4%). Soil water content (SWC) within depth of 1-m profile was differentiated at the start of measurements in the middle of June 2015. The SWC was the highest in non-eroded and depositional soils and the smallest in severely and very severely eroded soils. The difference of 5% has maintained during the whole growing season and did not affect the growth of plants till the phase of flowering. Then, the plants on shallower soils passed quicker to the next phenological phases in comparison to the plants on deeper

  13. Depth Profiles of Persistent Organic Pollutants in the North and Tropical Atlantic Ocean.

    PubMed

    Sun, Caoxin; Soltwedel, Thomas; Bauerfeind, Eduard; Adelman, Dave A; Lohmann, Rainer

    2016-06-21

    Little is known of the distribution of persistent organic pollutants (POPs) in the deep ocean. Polyethylene passive samplers were used to detect the vertical distribution of truly dissolved POPs at two sites in the Atlantic Ocean. Samplers were deployed at five depths covering 26-2535 m in the northern Atlantic and Tropical Atlantic, in approximately one year deployments. Samplers of different thickness were used to determine the state of equilibrium POPs reached in the passive samplers. Concentrations of POPs detected in the North Atlantic near the surface (e.g., sum of 14 polychlorinated biphenyls, PCBs: 0.84 pg L(-1)) were similar to previous measurements. At both sites, PCB concentrations showed subsurface maxima (tropical Atlantic Ocean -800 m, North Atlantic -500 m). Currents seemed more important in moving POPs to deeper water masses than the biological pump. The ratio of PCB concentrations in near surface waters (excluding PCB-28) between the two sites was inversely correlated with congeners' subcooled liquid vapor pressure, in support of the latitudinal fractionation. The results presented here implied a significant amount of HCB is stored in the Atlantic Ocean (4.8-26% of the global HCB environmental burdens), contrasting traditional beliefs that POPs do not reach the deep ocean. PMID:27174500

  14. Depth of maximum of air-shower profiles at the Pierre Auger Observatory. II. Composition implications

    SciTech Connect

    Aab, A.; et al.

    2014-12-31

    Using the data taken at the Pierre Auger Observatory between December 2004 and December 2012, we have examined the implications of the distributions of depths of atmospheric shower maximum (Xmax), using a hybrid technique, for composition and hadronic interaction models. We do this by fitting the distributions with predictions from a variety of hadronic interaction models for variations in the composition of the primary cosmic rays and examining the quality of the fit. Regardless of what interaction model is assumed, we find that our data are not well described by a mix of protons and iron nuclei over most of the energy range. Acceptable fits can be obtained when intermediate masses are included, and when this is done consistent results for the proton and iron-nuclei contributions can be found using the available models. We observe a strong energy dependence of the resulting proton fractions, and find no support from any of the models for a significant contribution from iron nuclei. However, we also observe a significant disagreement between the models with respect to the relative contributions of the intermediate components.

  15. Physical mechanisms of thermal-diffusivity depth-profile generation in a hardened low-alloy Mn, Si, Cr, Mo steel reconstructed by photothermal radiometry

    SciTech Connect

    Nicolaides, Lena; Mandelis, Andreas; Beingessner, Clare J.

    2001-06-15

    It is well established that in hardened steels thermal-diffusivity broadly anticorrelates with microhardness, allowing thermal-wave depth profilometry to be used as a tool to measure microhardness profiles. Nevertheless, the physical mechanisms for this anticorrelation have not been well understood. In this work, the thermal-diffusivity profiles of rough, hardened industrial steels were reconstructed after the elimination of roughness effects from the experimental data. Carburizing and quenching are widely used for the heat treatment of steel components, and it is important to understand their effects on thermal-diffusivity profiles. A thorough examination of the actual mechanism by which thermal-diffusivity depth profiles are affected by first carburizing and then quenching AISI-8620 steels was performed. It was concluded that the variation of thermal diffusivity with depth is dominated by the carbon concentration profile, whereas the absolute value of the thermal diffusivity is a function of microstructure. {copyright} 2001 American Institute of Physics.

  16. Characterization of magnetic property depth profiles of surface-modified materials using a model-assisted swept frequency modulation field technique

    NASA Astrophysics Data System (ADS)

    Lo, C. C. H.

    2009-04-01

    This paper reports on a model-assisted approach to characterizing surface-modified materials whose magnetic properties vary continuously with depth. The technique involves measuring ac permeability profiles under a quasistatic biasing field superimposed with an ac modulation field of adjustable frequency and amplitude to control field penetration depth. A frequency dependent magnetic hysteresis model was used to model ac permeability profiles at different modulation field frequencies for direct comparison with measurement results. The approach was applied to characterize a series of surface hardened Fe-C samples. The depth dependence of the magnetic properties was determined by obtaining the best fits of the modeled ac permeability profiles to experimental data at multiple modulation frequencies. The midpoints of the inverted magnetic property profiles and the measured hardness profiles were found to be in agreement.

  17. A study of the properties of beryllium doped silicon with particular emphasis on diffusion mechanisms: Profiles of depth dependent conductivity as determined by electrical surface probes

    NASA Technical Reports Server (NTRS)

    Franks, R. K.; Robertson, J. B.

    1972-01-01

    Very large diffusion coefficients were encountered and required the determination of impurity profiles for samples approximately 1 cm thick. Since conductivity values are readily converted into concentrations of electrically active impurities, the major problem became that of accurately determining the conductivity profiles of beryllium diffused silicon samples. Four-point probe measurements on samples having depth conductivities are interpreted in terms of conductivity profiles, based on an exact solution of the problem of exponentially depth dependent conductivity. Applications include surface conductivity determination where the form of the conductivity profile is known, and conductivity profile determination from probe measurements taken as the sample surface is progressively lapped away. The application is limited to samples having conductivity monotonically decreasing with depth from the probed surface.

  18. Diode-laser-based water vapor differential absorption lidar (DIAL) profiler evaluation

    NASA Astrophysics Data System (ADS)

    Spuler, S.; Weckwerth, T.; Repasky, K. S.; Nehrir, A. R.; Carbone, R.

    2012-12-01

    We are in the process of evaluating the performance of an eye-safe, low-cost, diode-laser-based, water vapor differential absorption lidar (DIAL) profiler. This class of instrument may be capable of providing continuous water vapor and aerosol backscatter profiles at high vertical resolution in the atmospheric boundary layer (ABL) for periods of months to years. The technology potentially fills a national long term observing facility gap and could greatly benefit micro- and meso-meteorology, water cycle, carbon cycle and, more generally, biosphere-hydrosphere-atmosphere interaction research at both weather and climate variability time scales. For the evaluation, the Montana State University 3rd generation water vapor DIAL was modified to enable unattended operation for a period of several weeks. The performance of this V3.5 version DIAL was tested at MSU and NCAR in June and July of 2012. Further tests are currently in progress with Howard University at Beltsville, Maryland; and with the National Weather Service and Oklahoma University at Dallas/Fort Worth, Texas. The presentation will include a comparison of DIAL profiles against meteorological "truth" at the aforementioned locations including: radiosondes, Raman lidars, microwave and IR radiometers, AERONET and SUOMINET systems. Instrument reliability, uncertainty, systematic biases, detection height statistics, and environmental complications will be evaluated. Performance will be judged in the context of diverse scientific applications that range from operational weather prediction and seasonal climate variability, to more demanding climate system process studies at the land-canopy-ABL interface. Estimating the extent to which such research and operational applications can be satisfied with a low cost autonomous network of similar instruments is our principal objective.

  19. Feasibility of tropospheric water vapor profiling using infrared heterodyne differential absorption lidar

    NASA Astrophysics Data System (ADS)

    Grund, Christian J.; Hardesty, R. Michael; Rye, Barry J.

    1995-04-01

    Continuous, high quality profiles of water vapor, free of systematic bias, and of moderate temporal and spatial resolution, acquired over long periods at low operational and maintenance cost, are fundamental to the success of the ARM CART program. The development and verification of realistic climate model parameterizations for clouds and net radiation balance, and the correction of other CART site sensor observations for interferences due to the presence of water vapor are critically dependent on water vapor profile measurements. Application of profiles acquired with current techniques, have, to date, been limited by vertical resolution and uniqueness of solution (e.g. high resolution infrared (IR) Fourier transform radiometry), poor spatial and temporal coverage and high operating cost (e.g. radiosondes), or diminished daytime performance, lack of eye-safety, and high maintenance cost (e.g. Raman lidar). Recent developments in infrared laser and detector technology make possible compact IR differential absorption lidar (DIAL) systems at eye-safe wavelengths. In the study reported here, we develop DIAL system performance models and examine the potential to solve some of the shortcomings of previous methods using parameterizations representative of current technologies. These models are also applied to diagnose and evaluate other strengths and weaknesses unique to the DIAL method for this application. This work is to continue in the direction of evaluating yet smaller and lower-cost laser diode-based systems for routine monitoring of the lower altitudes using photon counting detection methods. We regard the present report as interim in nature and will update and extend it as a final report at the end of the term of the contract.

  20. Feasibility of tropospheric water vapor profiling using infrared heterodyne differential absorption lidar

    SciTech Connect

    Grund, C.J.; Hardesty, R.M.; Rye, B.J.

    1995-04-03

    Continuous, high quality profiles of water vapor, free of systematic bias, and of moderate temporal and spatial resolution, acquired over long periods at low operational and maintenance cost, are fundamental to the success of the ARM CART program. The development and verification of realistic climate model parameterizations for clouds and net radiation balance, and the correction of other CART site sensor observations for interferences due to the presence of water vapor are critically dependent on water vapor profile measurements. Application of profiles acquired with current techniques, have, to date, been limited by vertical resolution and uniqueness of solution [e.g. high resolution infrared (IR) Fourier transform radiometry], poor spatial and temporal coverage and high operating cost (e.g. radiosondes), or diminished daytime performance, lack of eye-safety, and high maintenance cost (e.g. Raman lidar). Recent developments in infrared laser and detector technology make possible compact IR differential absorption lidar (DIAL) systems at eye-safe wavelengths. In the study reported here, we develop DIAL system performance models and examine the potential of to solve some of the shortcomings of previous methods using parameterizations representative of current technologies. These models are also applied to diagnose and evaluate other strengths and weaknesses unique to the DIAL method for this application. This work is to continue in the direction of evaluating yet smaller and lower-cost laser diode-based systems for routine monitoring of the lower altitudes using photon counting detection methods. We regard the present report as interim in nature and will update and extend it as a final report at the end of the term of the contract.

  1. Depth profiles of a shallow implanted layer in a Si wafer determined by different methods of thin-layer analysis1

    NASA Astrophysics Data System (ADS)

    Klockenkämper, R.; Becker, H. W.; Bubert, H.; Jenett, H.; von Bohlen, A.

    2002-10-01

    Several different methods of thin-layer analysis have been applied to depth profiling of the same sample on the nanometer scale: two variants of Monte Carlo simulations, X-ray photoelectron spectrometry (XPS) with sputtering, sputtered neutrals mass spectrometry (SNMS), grazing-incidence X-ray fluorescence (GI-XRF), Rutherford backscattering (RBS) and a newly developed method, i.e. a combination of wet-chemical etching and total-reflection X-ray fluorescence (TXRF). Depth profiles were recorded for a silicon wafer implanted with Co ions at a dose of 10 17 cm -2. For a detailed comparison, the results were expressed as basic quantities in SI units: the depth in m or nm and the concentration in mole mole -1. The depth profiles were shown to differ significantly. Characteristic parameters, e.g. the maximum, the respective depth, the width and the dose or area of the profiles differ by a factor up to 3, the offset of the profiles (surface value at depth zero) even differs by more than one order of magnitude. The reason for such discrepancies were mainly found in an unsuitable calibration leading to high systematic errors. However, RBS and the new variant of TXRF showed reasonable, consistent profiles and a good correspondence which could be verified statistically after an estimation of their uncertainties.

  2. Quantification of Hydrogen Concentrations in Surface and Interface Layers and Bulk Materials through Depth Profiling with Nuclear Reaction Analysis.

    PubMed

    Wilde, Markus; Ohno, Satoshi; Ogura, Shohei; Fukutani, Katsuyuki; Matsuzaki, Hiroyuki

    2016-01-01

    Nuclear reaction analysis (NRA) via the resonant (1)H((15)N,αγ)(12)C reaction is a highly effective method of depth profiling that quantitatively and non-destructively reveals the hydrogen density distribution at surfaces, at interfaces, and in the volume of solid materials with high depth resolution. The technique applies a (15)N ion beam of 6.385 MeV provided by an electrostatic accelerator and specifically detects the (1)H isotope in depths up to about 2 μm from the target surface. Surface H coverages are measured with a sensitivity in the order of ~10(13) cm(-2) (~1% of a typical atomic monolayer density) and H volume concentrations with a detection limit of ~10(18) cm(-3) (~100 at. ppm). The near-surface depth resolution is 2-5 nm for surface-normal (15)N ion incidence onto the target and can be enhanced to values below 1 nm for very flat targets by adopting a surface-grazing incidence geometry. The method is versatile and readily applied to any high vacuum compatible homogeneous material with a smooth surface (no pores). Electrically conductive targets usually tolerate the ion beam irradiation with negligible degradation. Hydrogen quantitation and correct depth analysis require knowledge of the elementary composition (besides hydrogen) and mass density of the target material. Especially in combination with ultra-high vacuum methods for in-situ target preparation and characterization, (1)H((15)N,αγ)(12)C NRA is ideally suited for hydrogen analysis at atomically controlled surfaces and nanostructured interfaces. We exemplarily demonstrate here the application of (15)N NRA at the MALT Tandem accelerator facility of the University of Tokyo to (1) quantitatively measure the surface coverage and the bulk concentration of hydrogen in the near-surface region of a H2 exposed Pd(110) single crystal, and (2) to determine the depth location and layer density of hydrogen near the interfaces of thin SiO2 films on Si(100). PMID:27077920

  3. Neutron Depth Profiling benchmarking and analysis of applications to lithium ion cell electrode and interfacial studies research

    NASA Astrophysics Data System (ADS)

    Whitney, Scott M.

    The role of the lithium ion cell is increasing with great intensity due to global concerns for the decreased use of fossil fuels as well as the growing popularity of portable electronics. With the dramatic increase in demand for these cells follows an outbreak of research to optimize the lithium ion cells in terms of safety, cost, and also performance. The work shown in this dissertation sets out to distinguish the role of Neutron Depth Profiling (NDP) in the expanding research of lithium ion cells. Lithium ions play the primary role in the performance of lithium ion batteries. Moving from anode to cathode, and cathode to anode, the lithium ions are constantly being disturbed during the cell's operation. The ability to accurately determine the lithium's behavior within the electrodes of the cell after different operating conditions is a powerful tool to better understand the faults and advantages of particular electrode compositions and cell designs. NDP has this ability through the profiling of 6Li. This research first validates the ability of The University of Texas NDP (UT-NDP) facility to accurately profile operated lithium ion cell electrodes to a precision within 2% over 10 mum for concentration values, and with a precision for depth measurements within 77 nm. The validation of the UT-NDP system is performed by comparing UT-NDP profiles to those from the NIST-NDP system, from the Secondary Ion Mass Spectrometry (SIMS) technique, and also from Monte Carlo n-Particle (MCNPX) code simulations. All of the comparisons confirmed that the UT-NDP facility is fully capable of providing accurate depth profiles of lithium ion cell electrodes in terms of depth, shape of distribution, and concentration. Following the validation studies, this research investigates three different areas of lithium ion cell research and provides analysis based on NDP results. The three areas of investigation include storage of cells at temperature, cycling of cells, and the charging of cells

  4. Vertical and Horizontal Corneal Epithelial Thickness Profile Using Ultra-High Resolution and Long Scan Depth Optical Coherence Tomography

    PubMed Central

    Jiang, Hong; Xu, Zhe; Perez, Victor; Wang, Jianhua

    2014-01-01

    Purpose To determine the vertical and horizontal thickness profiles of the corneal epithelium in vivo using ultra-long scan depth and ultra-high resolution spectral domain optical coherence tomography (SD-OCT). Methods A SD-OCT was developed with an axial resolution of ∼3.3 µm in tissue and an extended scan depth. Forty-two eyes of 21 subjects were imaged twice. The entire horizontal and vertical corneal epithelial thickness profiles were evaluated. The coefficient of repeatability (CoR) and intraclass correlation (ICC) of the tests and interobserver variability were analyzed. Results The full width of the horizontal epithelium was detected, whereas part of the superior epithelium was not shown for the covered super eyelid. The mean central epithelial corneal thickness was 52.0±3.2 µm for the first measurement and 52.3±3.4 µm for the second measurement (P>.05). In the central zone (0–3.0 mm), the paracentral zones (3.0–6.0 mm) and the peripheral zones (6.0–10.0 mm), the mean epithelial thickness ranged from 51 to 53 µm, 52 to 57 µm, and 58 to 72 µm, respectively. There was no difference between the two tests at both meridians and in the right and left eyes (P>.05). The ICCs of the two tests ranged from 0.70 to 0.97 and the CoRs ranged from 2.5 µm to 7.8 µm from the center to the periphery, corresponding to 5.6% to 10.6% (CoR%). The ICCs of the two observers ranged from 0.72 to 0.93 and the CoRs ranged from 4.5 µm to 10.4 µm from the center to the periphery, corresponding to 8.7% to 15.2% (CoR%). Conclusions This study demonstrated good repeatability of ultra-high resolution and long scan depth SD-OCT to evaluate the entire thickness profiles of the corneal epithelium. The epithelial thickness increases from the center toward the limbus. PMID:24844566

  5. NONLINEAR-APPROXIMATION TECHNIQUE FOR DETERMINING VERTICAL OZONE-CONCENTRATION PROFILES WITH A DIFFERENTIAL-ABSORPTION LIDAR

    EPA Science Inventory

    A new technique is presented for the retrieval of ozone concentration profiles from backscattered signals obtained by a multi-wavelength differential-absorption lidar (DIAL). The technique makes it possible to reduce erroneous local fluctuations induced in the ozone-concentration...

  6. Wavelet based de-noising of breath air absorption spectra profiles for improved classification by principal component analysis

    NASA Astrophysics Data System (ADS)

    Kistenev, Yu. V.; Shapovalov, A. V.; Borisov, A. V.; Vrazhnov, D. A.; Nikolaev, V. V.; Nikiforova, O. Yu.

    2015-11-01

    The comparison results of different mother wavelets used for de-noising of model and experimental data which were presented by profiles of absorption spectra of exhaled air are presented. The impact of wavelets de-noising on classification quality made by principal component analysis are also discussed.

  7. 2D Self-Similar Profile for Laser Beam Propagation in Medium with Saturating Multi-Photon Absorption

    NASA Astrophysics Data System (ADS)

    Trofimov, Vyacheslav A.; Lysak, Tatiana M.; Zakharova, Irina G.

    2016-02-01

    We study a self-similar mode of 2D laser beam propagation in media with multiphoton absorption (MA) taking into account a resonant nonlinearity and nonlinear absorption saturating. An analytical solution of the corresponding equations describing the problems under consideration is derived using an eigenvalue problem method generalization for soliton- like solution finding. The developed solution is used as incident beam profile and phase front for computer simulation of the 2D laser beam propagation. In particular, we demonstrate numerically that the laser beam propagation in a self-similar mode occurs within a certain distance, which depends on medium properties. Under certain relations between the nonlinear absorption and resonant nonlinearity, and cubic nonlinear response, we observe the super long distance of the beam propagation without any beam profile distributions.

  8. Conformational behaviour of humic substances at different depths along a profile of a Lithosol under loblolly (Pinus taeda) plantation

    NASA Astrophysics Data System (ADS)

    Conte, P.; Maia, C. M. B. F.; de Pasquale, C.; Alonzo, G.

    2009-04-01

    The conformation of natural organic matter (NOM) plays a key role in many physical and chemical processes including interactions with organic and inorganic pollutants and soil aggregates stability thus directly influencing soil quality. NOM conformation can be studied by solid state NMR spectroscopy with cross polarization and magic angle spinning (CPMAS NMR). In the present study we applied CPMAS 13C NMR spectroscopy on three humic acid fractions (HA) each extracted from a different horizon in a Lithosol profile under Pinus taeda. Results showed that the most superficial HA was also the most aliphatic in character. Amount of aromatic moieties and hydrophilic HA constituents increased along the profile. Cross polarization (TCH) and longitudinal relaxation protons times in the rotating frame (T1rho(H)) were measured and compared only for the NMR signals generated by carboxyls and alkyls. This because the signal intensity for the aromatic, C-O and C-N systems was very low, thereby preventing suitable evaluation of TCH and T1rho(H) values for such systems. The cross polarization times of carboxyls decreased, whereas those of the alkyl moieties increased with depth. Conversely, T1rho(H) values increased for both COOH and alkyl groups along the profile. Polarization transfer from protons to carbons is affected by the dipolar interactions among the nuclei. The stronger the H-C dipolar interaction, the faster is the rate of the energy exchange. All the factors affecting the dipolar interaction strength also influence the rate of magnetization transfer. Among the others, fast molecular tumbling and poor proton density around the carbons are responsible for long TCH values. Molecular tumbling and proton density also affect T1rho(H) values. Namely, the larger the molecular tumbling and the proton density, the faster is the proton longitudinal relaxation rate in the rotating frame (shorter T1rho(H) values). The decrease of TCH values of COOH groups along the profile was

  9. DMD-based software-configurable spatially-offset Raman spectroscopy for spectral depth-profiling of optically turbid samples.

    PubMed

    Liao, Zhiyu; Sinjab, Faris; Gibson, Graham; Padgett, Miles; Notingher, Ioan

    2016-06-13

    Spectral depth-profiling of optically turbid samples is of high interest to a broad range of applications. We present a method for measuring spatially-offset Raman spectroscopy (SORS) over a range of length scales by incorporating a digital micro-mirror device (DMD) into a sample-conjugate plane in the detection optical path. The DMD can be arbitrarily programmed to collect/reject light at spatial positions in the 2D sample-conjugate plane, allowing spatially offset Raman measurements. We demonstrate several detection geometries, including annular and simultaneous multi-offset modalities, for both macro- and micro-SORS measurements, all on the same instrument. Compared to other SORS modalities, DMD-based SORS provides more flexibility with only minimal additional experimental complexity for subsurface Raman collection. PMID:27410290

  10. Depth distribution of 137Cs, 134Cs, and 131I in soil profile after Fukushima Dai-ichi Nuclear Power Plant Accident.

    PubMed

    Kato, Hiroaki; Onda, Yuichi; Teramage, Mengistu

    2012-09-01

    Soil, vegetation and other ecological compartments are expected to be highly contaminated by the deposited radionuclides after the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident triggered by a magnitude 9.0 earthquake and the resulting tsunami on 11 March 2011. However, there is no field measurement data on the depth distributions of radiocaesium and (131)I concentrations in soil profile. In this study, the depth distribution of the deposited radionuclides in the cultivated soil profile was investigated in one of the most contaminated area after FDNPP accident. The result of this study demonstrated that greater than 86% of total radiocaesium and 79% of total (131)I were absorbed in the upper 2.0 cm in the soil profile. The relaxation mass depth (h(0)) derived from the depth distribution of radiocaesium and (131)I in the soil profile at the study site were 9.1 kg m(-2) and 10.4 kg m(-2), respectively. The h(0) of (137)Cs in the studied soil profile was greater than those for the cultivated soils nearby the Chernobyl NPP. The positive relationship was found between clay content of topsoil and the h(0) of (137)Cs. However, further analysis is required to clarify the effect of clay content on the initial penetration depth of deposited (137)Cs in soil profile. PMID:22029969

  11. Evaluation of depth profiling using laser resonant desorption as a method to measure diffusion coefficients in ice.

    PubMed

    Dominé, F; Xueref, I

    2001-09-01

    Diffusion of gases in ice is involved in cloud, snow, and ice core chemistry, but few data exist on the relevant diffusion coefficients. A novel method to measure diffusion coefficients in ice has recently been proposed by Livingston et al. (Anal. Chem., 2000, 72, 5590-5599). It is based on depth profiling of doped ice crystals epitaxially grown on Ru(001) by laser resonant desorption (LRD). Using this method, Livingston et al. obtained a value of the diffusion coefficient of the HCl hydrate in ice at 190 K of about 5 x 10(-11) cm2/s. We argue here that this value is many orders of magnitude higher than what could be expected from literature values, which are not reported in sufficient detail by Livingston et al. We investigate the possibilities that their high value could be due to (1) diffusion in defects in the ice, which would be present in very high concentrations because of the ice growth method; and (2) the fact that diffusion of high concentrations of HCl in ice at 190 K forms an amorphous HCl:H2O solid mixture, where HCl diffusion is fast. We present new infrared spectroscopic data on solid HCl:H2O mixtures that confirm that such mixtures can indeed be formed in an amorphous state at 190 K. Our proposed interpretation is that by depositing large amounts of HCl on epitaxially grown ice, Livingston et al. created a superficial amorphous binary mixture and that fast diffusion of HCl in the ice, possibly accelerated by a high defect density, produced an amorphous HCl:H2O mixture. We conclude that the processes studied by Livingston et al. are different from those involved in the atmospheric and cryospheric sciences, and that their data, obtained by depth profiling using LRD, probably cannot be applied to those fields. PMID:11569830

  12. Detection in the ppm range and high-resolution depth profiling with the new SNMS instrument INA-X

    NASA Astrophysics Data System (ADS)

    Jorzick, J.; Lösch, J.; Kopnarski, M.; Oechsner, H.

    The design and the specification of the newly developed INA-X instrument for the electron-gas version of a secondary neutral mass spectrometer (SNMS) are described. A modified plasma chamber inside a UHV vessel in combination with optimized r.f. coupling enable a high plasma density at low power input. The ionization efficiency and the current density for sample sputtering are significantly improved compared to those of previous SNMS instruments. A novel detection optics allows us to define an energy window of 1-2 eV. The secondary neutral particle flux is collected under an oblique take-off angle against the surface normal, improving the quantifiability of the obtained SNMS spectra. The variable sputtering rate can be adjusted from some nm per min up to 1-2 μm per min, depending on the operator's need, either to obtain high depth resolution or short analysis time. Examples for depth profiling of conducting and insulating films and coatings on the nano- and micrometer scales are presented.

  13. Depth-kymography of vocal fold vibrations: part II. Simulations and direct comparisons with 3D profile measurements

    NASA Astrophysics Data System (ADS)

    de Mul, Frits F. M.; George, Nibu A.; Qiu, Qingjun; Rakhorst, Gerhard; Schutte, Harm K.

    2009-07-01

    We report novel direct quantitative comparisons between 3D profiling measurements and simulations of human vocal fold vibrations. Until now, in human vocal folds research, only imaging in a horizontal plane was possible. However, for the investigation of several diseases, depth information is needed, especially when the two folds act differently, e.g. in the case of tumour growth. Recently, with our novel depth-kymographic laryngoscope, we obtained calibrated data about the horizontal and vertical positions of the visible surface of the vibrating vocal folds. In order to find relations with physical parameters such as elasticity and damping constants, we numerically simulated the horizontal and vertical positions and movements of the human vocal folds while vibrating and investigated the effect of varying several parameters on the characteristics of the phonation: the masses and their dimensions, the respective forces and pressures, and the details of the vocal tract compartments. Direct one-to-one comparison with measured 3D positions presents—for the first time—a direct means of validation of these calculations. This may start a new field in vocal folds research.

  14. Modelling the evolution of composition-and stress-depth profiles in austenitic stainless steels during low-temperature nitriding

    NASA Astrophysics Data System (ADS)

    Jespersen, Freja N.; Hattel, Jesper H.; Somers, Marcel A. J.

    2016-02-01

    Nitriding of stainless steel causes a surface zone of expanded austenite, which improves the wear resistance of the stainless steel while preserving the stainless behaviour. During nitriding huge residual stresses are introduced in the treated zone, arising from the volume expansion that accompanies the dissolution of high nitrogen contents in expanded austenite. An intriguing phenomenon during low-temperature nitriding is that the residual stresses evoked by dissolution of nitrogen in the solid state, affect the thermodynamics and the diffusion kinetics of nitrogen dissolution. In the present paper solid mechanics was combined with thermodynamics and diffusion kinetics to simulate the evolution of composition-depth and stress-depth profiles resulting from nitriding. The model takes into account a composition-dependent diffusion coefficient of nitrogen in expanded austenite, short range ordering (trapping) of nitrogen atoms by chromium atoms, and the effect of composition-induced stress on surface concentration and diffusive flux. The effect of plasticity and concentration-dependence of the yield stress was also included.

  15. High-resolution chemical depth profiling of solid material using a miniature laser ablation/ionization mass spectrometer.

    PubMed

    Grimaudo, Valentine; Moreno-García, Pavel; Riedo, Andreas; Neuland, Maike B; Tulej, Marek; Broekmann, Peter; Wurz, Peter

    2015-02-17

    High-resolution chemical depth profiling measurements of copper films are presented. The 10 μm thick copper test samples were electrodeposited on a Si-supported Cu seed under galvanostatic conditions in the presence of particular plating additives (SPS, Imep, PEI, and PAG) used in the semiconductor industry for the on-chip metallization of interconnects. To probe the trend of these plating additives toward inclusion into the deposit upon growth, quantitative elemental mass spectrometric measurements at trace level concentration were conducted by using a sensitive miniature laser ablation ionization mass spectrometer (LIMS), originally designed and developed for in situ space exploration. An ultrashort pulsed laser system (τ ∼ 190 fs, λ = 775 nm) was used for ablation and ionization of sample material. We show that with our LIMS system, quantitative chemical mass spectrometric analysis with an ablation rate at the subnanometer level per single laser shot can be conducted. The measurement capabilities of our instrument, including the high vertical depth resolution coupled with high detection sensitivity of ∼10 ppb, high dynamic range ≥10(8), measurement accuracy and precision, is of considerable interest in various fields of application, where investigations with high lateral and vertical resolution of the chemical composition of solid materials are required, these include, e.g., wafers from semiconductor industry or studies on space weathered samples in space research. PMID:25642789

  16. Systematic Temperature Effects in the Argon Cluster Ion Sputter Depth Profiling of Organic Materials Using Secondary Ion Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Seah, Martin P.; Havelund, Rasmus; Gilmore, Ian S.

    2016-08-01

    A study is presented of the effects of sample temperature on the sputter depth profiling of two organic materials, NPB ( N,N'-Di(1-naphthyl)- N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine) and Irganox 1010, using a 5 keV Ar2000 + cluster ion beam and analysis by secondary ion mass spectrometry. It is shown that at low temperatures, the yields increase slowly with temperature in accordance with the Universal Sputtering Yield equation where the energy term is now modified by Trouton's rule. This occurs up to a transition temperature, T T, which is, in turn, approximately 0.8 T M, where T M is the sample melting temperature in Kelvin. For NPB and Irganox 1010, these transition temperatures are close to 15 °C and 0 °C, respectively. Above this temperature, the rate of increase of the sputtering yield rises by an order of magnitude. During sputtering, the depth resolution also changes with temperature with a very small change occurring below T T. At higher temperatures, the depth resolution improves but then rapidly degrades, possibly as a result first of local crater surface diffusion and then of bulk inter-diffusion. The secondary ion spectra also change with temperature with the intensities of the molecular entities increasing least. This agrees with a model in which the molecular entities arise near the crater rim. It is recommended that for consistent results, measurements for organic materials are always made at temperatures significantly below T T or 0.8 T M, and this is generally below room temperature.

  17. Systematic Temperature Effects in the Argon Cluster Ion Sputter Depth Profiling of Organic Materials Using Secondary Ion Mass Spectrometry.

    PubMed

    Seah, Martin P; Havelund, Rasmus; Gilmore, Ian S

    2016-08-01

    A study is presented of the effects of sample temperature on the sputter depth profiling of two organic materials, NPB (N,N'-Di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine) and Irganox 1010, using a 5 keV Ar2000 (+) cluster ion beam and analysis by secondary ion mass spectrometry. It is shown that at low temperatures, the yields increase slowly with temperature in accordance with the Universal Sputtering Yield equation where the energy term is now modified by Trouton's rule. This occurs up to a transition temperature, T T, which is, in turn, approximately 0.8T M, where T M is the sample melting temperature in Kelvin. For NPB and Irganox 1010, these transition temperatures are close to 15 °C and 0 °C, respectively. Above this temperature, the rate of increase of the sputtering yield rises by an order of magnitude. During sputtering, the depth resolution also changes with temperature with a very small change occurring below T T. At higher temperatures, the depth resolution improves but then rapidly degrades, possibly as a result first of local crater surface diffusion and then of bulk inter-diffusion. The secondary ion spectra also change with temperature with the intensities of the molecular entities increasing least. This agrees with a model in which the molecular entities arise near the crater rim. It is recommended that for consistent results, measurements for organic materials are always made at temperatures significantly below T T or 0.8 T M, and this is generally below room temperature. Graphical Abstract ᅟ. PMID:27106601

  18. Systematic Temperature Effects in the Argon Cluster Ion Sputter Depth Profiling of Organic Materials Using Secondary Ion Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Seah, Martin P.; Havelund, Rasmus; Gilmore, Ian S.

    2016-04-01

    A study is presented of the effects of sample temperature on the sputter depth profiling of two organic materials, NPB (N,N'-Di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine) and Irganox 1010, using a 5 keV Ar2000 + cluster ion beam and analysis by secondary ion mass spectrometry. It is shown that at low temperatures, the yields increase slowly with temperature in accordance with the Universal Sputtering Yield equation where the energy term is now modified by Trouton's rule. This occurs up to a transition temperature, T T, which is, in turn, approximately 0.8T M, where T M is the sample melting temperature in Kelvin. For NPB and Irganox 1010, these transition temperatures are close to 15 °C and 0 °C, respectively. Above this temperature, the rate of increase of the sputtering yield rises by an order of magnitude. During sputtering, the depth resolution also changes with temperature with a very small change occurring below T T. At higher temperatures, the depth resolution improves but then rapidly degrades, possibly as a result first of local crater surface diffusion and then of bulk inter-diffusion. The secondary ion spectra also change with temperature with the intensities of the molecular entities increasing least. This agrees with a model in which the molecular entities arise near the crater rim. It is recommended that for consistent results, measurements for organic materials are always made at temperatures significantly below T T or 0.8 T M, and this is generally below room temperature.

  19. Field-deployable diode-laser-based differential absorption lidar (DIAL) for profiling water vapor

    NASA Astrophysics Data System (ADS)

    Spuler, S. M.; Repasky, K. S.; Morley, B.; Moen, D.; Hayman, M.; Nehrir, A. R.

    2015-03-01

    A field-deployable water vapor profiling instrument that builds on the foundation of the preceding generations of diode-laser-based differential absorption lidar (DIAL) laboratory prototypes was constructed and tested. Significant advances are discussed, including a unique shared telescope design that allows expansion of the outgoing beam for eye-safe operation with optomechanical and thermal stability; multistage optical filtering enabling measurement during daytime bright-cloud conditions; rapid spectral switching between the online and offline wavelengths enabling measurements during changing atmospheric conditions; and enhanced performance at lower ranges by the introduction of a new filter design and the addition of a wide field-of-view channel. Performance modeling, testing, and intercomparisons are performed and discussed. In general, the instrument has a 150 m range resolution with a 10 min temporal resolution; 1 min temporal resolution in the lowest 2 km of the atmosphere is demonstrated. The instrument is shown capable of autonomous long-term field operation - 50 days with a > 95% uptime - under a broad set of atmospheric conditions and potentially forms the basis for a ground-based network of eye-safe autonomous instruments needed for the atmospheric sciences research and forecasting communities.

  20. Field deployable diode-laser-based differential absorption lidar (DIAL) for profiling water vapor

    NASA Astrophysics Data System (ADS)

    Spuler, S. M.; Repasky, K. S.; Morley, B.; Moen, D.; Hayman, M.; Nehrir, A. R.

    2014-11-01

    A field deployable water vapor profiling instrument that builds on the foundation of the preceding generations of diode-laser-based differential absorption lidar (DIAL) laboratory prototypes has been constructed and tested. Significant advances are discussed, including: a unique shared telescope design that allows expansion of the outgoing beam for eye-safe operation with opto-mechanical and thermal stability, multi-stage optical filtering enabling measurement during daytime bright-cloud conditions, rapid spectral switching between the online and offline wavelengths enabling measurements during changing atmospheric conditions, and enhanced performance at lower ranges by the introduction of a new filter design and the addition of a wide field-of-view channel. Performance modeling, testing and intercomparisons have been performed and are discussed. In general, the instrument has 150 m range resolution with 10 min temporal resolution - 1 min temporal resolution in the lowest 2 km of the atmosphere is demonstrated. The instrument was shown capable of autonomous long term field operation - 50 days with a >95% uptime - under a broad set of atmospheric conditions and potentially forms the basis for a ground-based network of eye-safe autonomous instruments needed for the atmospheric sciences research and forecasting communities.

  1. Absolute hydrogen depth profiling using the resonant 1H(15N, αγ)12C nuclear reaction

    NASA Astrophysics Data System (ADS)

    Reinhardt, Tobias P.; Akhmadaliev, Shavkat; Bemmerer, Daniel; Stöckel, Klaus; Wagner, Louis

    2016-08-01

    Resonant nuclear reactions are a powerful tool for the determination of the amount and profile of hydrogen in thin layers of material. Usually, this tool requires the use of a standard of well-known composition. The present work, by contrast, deals with standard-less hydrogen depth profiling. This approach requires precise nuclear data, e.g. on the widely used 1 H(15 N, αγ)12 C reaction, resonant at 6.4 MeV 15 N beam energy. Here, the strongly anisotropic angular distribution of the emitted γ -rays from this resonance has been re-measured, resolving a previous discrepancy. Coefficients of (0.38 ± 0.04) and (0.80 ± 0.04) have been deduced for the second and fourth order Legendre polynomials, respectively. In addition, the resonance strength has been re-evaluated to (25.0 ± 1.5) eV, 10% higher than previously reported. A simple working formula for the hydrogen concentration is given for cases with known γ -ray detection efficiency. Finally, the absolute approach is illustrated using two examples.

  2. High-throughput and targeted in-depth mass spectrometry-based approaches for biofluid profiling and biomarker discovery.

    PubMed

    Jimenez, Connie R; Piersma, Sander; Pham, Thang V

    2007-12-01

    Proteomics aims to create a link between genomic information, biological function and disease through global studies of protein expression, modification and protein-protein interactions. Recent advances in key proteomics tools, such as mass spectrometry (MS) and (bio)informatics, provide tremendous opportunities for biomarker-related clinical applications. In this review, we focus on two complementary MS-based approaches with high potential for the discovery of biomarker patterns and low-abundant candidate biomarkers in biofluids: high-throughput matrix-assisted laser desorption/ionization time-of-flight mass spectroscopy-based methods for peptidome profiling and label-free liquid chromatography-based methods coupled to MS for in-depth profiling of biofluids with a focus on subproteomes, including the low-molecular-weight proteome, carrier-bound proteome and N-linked glycoproteome. The two approaches differ in their aims, throughput and sensitivity. We discuss recent progress and challenges in the analysis of plasma/serum and proximal fluids using these strategies and highlight the potential of liquid chromatography-MS-based proteomics of cancer cell and tumor secretomes for the discovery of candidate blood-based biomarkers. Strategies for candidate validation are also described. PMID:20477373

  3. Depth profiling of Stratum corneum hydration in vivo: a comparison between conductance and confocal Raman spectroscopic measurements.

    PubMed

    Boncheva, Mila; de Sterke, Johanna; Caspers, Peter J; Puppels, Gerwin J

    2009-10-01

    The high-frequency electrical conductance of tape-stripped human skin in vivo can be used to evaluate the hydration profile of Stratum corneum (SC). Tape-stripping provides access to the underlying SC layers, and the conductance of these layers (as measured by the Skicon instrument) correlates well with their water content, as demonstrated by independent confocal Raman spectroscopic measurements. The correlation shows high inter-individual variance and is not linear over the full measurement range of the instrument, but is helpful to discriminate between dry, normal and highly hydrated SC. The depth profile of hydration in tape-stripped SC corresponds to the one in intact SC only if the barrier function of the skin is not impaired. Thus, conductometry of tape-stripped skin must be used in conjunction with a method that allows to estimate the barrier damage inflicted to SC during the tape-stripping procedure, for example, measurement of the trans-epidermal water loss. The methodology described here is simple, rapid and minimally invasive, and it employs commercially available instrumentation that is cheap, portable and easy to use. This approach is applicable to in vivo estimation of the SC hydration in studies in the areas of dermatology, skin care and transdermal drug delivery. PMID:19469890

  4. In-Depth Analysis of a Plasma or Serum Proteome Using a 4D Protein Profiling Method

    PubMed Central

    Tang, Hsin-Yao; Beer, Lynn A.; Speicher, David W.

    2011-01-01

    Comprehensive proteomic analysis of human plasma or serum has been a major strategy used to identify biomarkers that serve as indicators of disease. However, such in-depth proteomic analyses are challenging due to the complexity and extremely large dynamic range of protein concentrations in plasma. Therefore, reduction in sample complexity through multidimensional pre-fractionation strategies is critical, particularly for the detection of low-abundance proteins that have the potential to be the most specific disease biomarkers. We describe here a 4D protein profiling method that we developed for comprehensive proteomic analyses of both plasma and serum. Our method consists of abundant protein depletion coupled with separation strategies – microscale solution isoelectrofocusing and 1D SDS-PAGE – followed by reversed-phase separation of tryptic peptides prior to LC–MS/MS. Using this profiling strategy, we routinely identify a large number of proteins over nine orders of magnitude, including a substantial number of proteins at the low ng/mL or lower levels from approximately 300 μL of plasma sample. PMID:21468940

  5. Cenozoic variations in the South Atlantic carbonate saturation profile: Insights from the Walvis depth-transect (ODP Leg 208)

    NASA Astrophysics Data System (ADS)

    Schellenberg, S. A.; Nielsen, J. L.

    2004-12-01

    Ocean Drilling Program Leg 208 Science Party (D. Kroon, J. C. Zachos, P. Blum, J. Bowles, P. Gaillot, T. Hasegawa, E. C. Hawthorne, D. A. Hodell, D. C. Kelly, J. Jung, S. M. Keller, Y. Lee, D. C. Leuschner, Z. Liu, K. C. Lohmann, L. Lourens, S. Monechi, M. Nicolo, I. Raffi, C. Riesselman, U. Röhl, D. Schmidt, A. Sluijs, D. Thomas, E. Thomas, H. Vallius) Carbonate saturation profiles are complex and dynamic products of processes operating on temporospatial scales from the "short-term local" (e.g. carbonate export production) to the "long-term global" (e.g. carbonate-silicate weathering, shelf:basin carbonate partitioning). Established, if admittedly crude, proxies for reconstructing carbonate saturation from sediments include wt% carbonate, where values of 0-20% are typically attributed to deposition below the carbonate compensation depth (CCD), and planktonic foraminifer fragmentation, where enhanced fragmentation is typically attributed to deposition below the lysocline. Ocean Drilling Program Leg 208 successfully drilled a six-site Walvis Ridge depth-transect spanning modern water depths from 2,717 to 4,755 m. Exceptional core recovery, well-constrained biomagnetostratigraphy, and standard crustal subsidence corrections provide a working age-depth framework for contouring ship-board wt% carbonate determinations and identifying the following first-order features of the regional CCD: (1) >3.5 km position from 60-48 Ma punctuated by a major transient shoaling to <2 km during the Paleocene-Eocene Thermal Maximum at ˜55 Ma; (2) shoaling to ˜2.75 km from 48 to 44 Ma; (3) subsequent deepening to >4.25 km from 37 to 28 Ma; (4) marked high amplitude fluctuations from 28 to 20 Ma followed by deepening to >4.75 km; (5) transient shoaling to ˜4 km around 15 Ma followed by deepening to >4.75 km by ˜12 Ma. These first-order features are broadly congruent with classic Atlantic CCD reconstructions by van Andel (1975) and Berger and Roth (1975). A wealth of higher frequency

  6. Detection of harmonics and recovery of the absorption line profile using logarithmic-transformed wavelength modulation spectroscopy

    NASA Astrophysics Data System (ADS)

    Cong, Menglong; Sun, Dandan

    2016-07-01

    A versatile signal processing strategy for eliminating the residual amplitude modulation (RAM) and distortion in tunable diode laser wavelength modulation spectroscopy is theoretically demonstrated and experimentally validated. The strategy involves logarithmic transformation and differential detection, which are achieved using a homemade circuit. Through the logarithmic transformation, the optical intensity modulation of the laser, which performs as the source of RAM and distortion, is separated from the absorption-induced power attenuation and further balanced during the differential detection. The first harmonic, which is proportional to the first-order derivative of the absorption line profile in the case of a small modulation index, is extracted along with the second harmonic and is integrated for the recovery of the absorption line profile. The experiments are carried out for CH4 at its R(3) absorption line of the 2ν3 overtone for validation of the system, and the derived results are found to be in good agreement with the theoretical simulations. These promising results indicate the high potential of the strategy for absorption spectrum-based determination of gas properties.

  7. Simultaneous depth-profiling of electrical and elemental properties of ion-implanted arsenic in silicon by combining secondary-ion mass spectrometry with resistivity measurements

    NASA Astrophysics Data System (ADS)

    Bennett, N. S.; Wong, C. S.; McNally, P. J.

    2016-07-01

    A method is proposed to extract the electrical data for surface doping profiles of semiconductors in unison with the chemical profile acquired by secondary-ion mass spectrometry (SIMS)—a method we call SIMSAR (secondary-ion mass spectrometry and resistivity). The SIMSAR approach utilizes the inherent sputtering process of SIMS, combined with sequential four-point van der Pauw resistivity measurements, to surmise the active doping profile as a function of depth. The technique is demonstrated for the case of ion-implanted arsenic doping profiles in silicon. Complications of the method are identified, explained, and corrections for these are given. While several techniques already exist for chemical dopant profiling and numerous for electrical profiling, since there is no technique which can measure both electrical and chemical profiles in parallel, SIMSAR has significant promise as an extension of the conventional dynamic SIMS technique, particularly for applications in the semiconductor industry.

  8. New Techniques of LASS-ICPMS Depth Profiling Applied to Detrital Zircon from the Central Alps-Apennines System

    NASA Astrophysics Data System (ADS)

    Anfinson, O. A.; Smye, A.; Stockli, D. F.

    2014-12-01

    Detrital zircon U-Pb age dating has become a widely used tool for determining sediment provenance in basins and orogenic systems. While traditional LA-ICPMS zircon geochronology is powerful, it has limitations when source regions are characterized by monotonous or non-diagnostic crystallization ages or by major sediment recycling and homogenization, leading to minimal zircon age variability. In the central Alps of Switzerland and Italy, for example, similar Cadomian, Caledonian, and Variscan zircons dominate with only minor Alpine ages. Samples collected from Oligocene-Miocene strata deposited in both the northern (Swiss Molasse) and southern (Apenninic foredeep) Alpine foreland basins document shifts in the relative abundance of Cadomian, Caledonian, Variscan and Alpine aged detrital zircon, but the exact source region and genesis of the grains remains poorly constrained based on zircon U-Pb age data alone. Laser Ablation Split Stream (LASS)-ICPMS depth profiling of detrital zircon allows for the simultaneous recovery of multiple ages and of chemical/petrogenetic data from single zircons, and has the potential to shed additional light on provenance. This study applies this approach to Oligocene-Miocene strata of the Swiss Molasse Basin and Apenninic foredeep. Recent advances in LA-ICPMS sample cell technology allow for reliable recovery of age and trace element data during progressive ablation into zircons. Decreased washout (<.3 sec) reduces vertical signal smearing during ablation and penetration into unpolished, tape-mounted grains. In contrast to traditional polished mount zircon spot-analysis, depth-profiling of unpolished grains minimizes zonal mixing given that ablation pits are commonly oriented perpendicular to growth zones. Split-stream analysis of U-Pb isotopic data and REE/trace element abundances during ablation improves petrochronologic resolution to the further elucidated the growth history and genesis of individual zircon grains. Results from the

  9. Recovery of x-ray absorption spectral profile in etched TiO{sub 2} thin films

    SciTech Connect

    Sano, Keiji; Niibe, Masahito; Kawakami, Retsuo; Nakano, Yoshitaka

    2015-05-15

    Near edge x-ray absorption fine structure (NEXAFS) spectra of plasma-etched TiO{sub 2} thin films were observed using the total fluorescence yield method involving visible emission. The disrupted spectrum recovered its as-grown (nonetched) profile, upon soft x-ray (SX) irradiation. This recovery was investigated by ultraviolet (UV) irradiation, spatial distribution measurements, exposing recovered samples to air, and NEXAFS measurements of ultrafine TiO{sub 2} particles. The spectral profile recovered upon UV irradiation, and at sample positions outside of the SX irradiation site. The recovered spectral profiles were disrupted again, upon exposure to air. Nonetched ultrafine TiO{sub 2} particles also exhibited a disrupted spectral profile, which was recovered upon SX irradiation. The spectral recovery is explained by a model involving electrons trapped in oxygen vacancies generated by etching.

  10. In-vivo measurements of penetration depth, oxygenation, and drug concentration using broadband absorption spectroscopy in human tissues before and after photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Wang, Hsing-Wen; Zhu, Timothy C.; Solonenko, Michael; Hahn, Stephen M.; Metz, James M.; Dimofte, Andrea; Mile, Jermy; Yodh, Arjun G.

    2003-06-01

    Photodynamic therapy (PDT) employs a combination of photosensitizing chemical, light, and oxygen Knowledge of tissue optical properties, including absorption (μa) and reduce scattering coefficients (μs"), makes possible to derive blood oxygen saturation, light penetration depth, and drug concentration, which are important to ensure PDT treatment efficacy at the specific wavelengths. We have developed an absorption spectroscopy system to measure μa and μs" in the spectral range 600-800nm using a contact linear probe with a source fiber and multiple source-detector separation distances less than 1 cm. The μa and μs" were recovered based on diffusion approximations of the photon transport equation. We measured tissue optical properties among various organs of patients with intraperitoneal malignancies for an on-going Phase II PDT protocol. The results from 12 patients showed various effective penetration depth from site to site and from organ to organ. The percentage oxygen saturation (%StO2) are similar before and after PDT. Before PDT, meff (mean (standard deviation) (number of patients)) in cm-1 at 630nm are 2.4 (0.2) (12) in small bowel, 2.2(0.4) (9) in large bowel, 4.2(2.7) (7) in tumor, 3.3 (0.3) (10) in peritoneum, 2.7 (0.3) (11) in skin, and 10.1 (0.6) (10) in liver. %StO2 is 60-80% for most organs but 30-40% for tumor.

  11. Analyses of hydrogen in quartz and in sapphire using depth profiling by ERDA at atmospheric pressure: Comparison with resonant NRA and SIMS

    NASA Astrophysics Data System (ADS)

    Reiche, Ina; Castaing, Jacques; Calligaro, Thomas; Salomon, Joseph; Aucouturier, Marc; Reinholz, Uwe; Weise, Hans-Peter

    2006-08-01

    Hydrogen is present in anhydrous materials as a result of their synthesis and of their environment during conservation. IBA provides techniques to measure H concentration depth profiles allowing to identify various aspects of the materials including the history of objects such as gemstones used in cultural heritage. A newly established ERDA set-up, using an external microbeam of alpha particles, has been developed to study hydrated near-surface layers in quartz and sapphire by non-destructive H depth profiling in different atmospheres. The samples were also analysed using resonant NRA and SIMS.

  12. BELINDA: Broadband Emission Lidar with Narrowband Determination of Absorption. A new concept for measuring water vapor and temperature profiles

    NASA Technical Reports Server (NTRS)

    Theopold, F. A.; Weitkamp, C.; Michaelis, W.

    1992-01-01

    We present a new concept for differential absorption lidar measurements of water vapor and temperature profiles. The idea is to use one broadband emission laser and a narrowband filter system for separation of the 'online' and 'offline' return signals. It is shown that BELINDA offers improvements as to laser emission shape and stability requirements, background suppression, and last and most important a significant reduction of the influence of Rayleigh scattering. A suitably designed system based on this concept is presented, capable of measuring water vapor or temperature profiles throughout the planetary boundary layer.

  13. One-Sample based Single-Valued Estimation of the Interface Profile from Intersubband Integrated Absorption Intensity Data

    NASA Astrophysics Data System (ADS)

    Nhu Thao, Dinh; Thanh Tien, Nguyen; Toan, Huynh Ngoc; Nhat Quang, Doan

    2016-07-01

    We prove the integrated absorption intensity due to intersubband optical transition in a quantum well (QW) to be a function of the correlation length of the interface roughness profile and independent of the roughness amplitude. We then develop a novel way to perform single-valued estimation of the interface roughness profile of QW from experiments conducted merely on one sample. The new method that we propose in this paper would be replicable and more economical than the traditional counterparts, which usually require at least two samples.

  14. Effect of a progressive sound wave on the profiles of spectral lines. 2: Asymmetry of faint Fraunhofer lines. [absorption spectra

    NASA Technical Reports Server (NTRS)

    Kostyk, R. I.

    1974-01-01

    The absorption coefficient profile was calculated for lines of different chemical elements in a medium with progressive sound waves. Calculations show that (1) the degree and direction of asymmetry depend on the atomic ionization potential and the potential of lower level excitation of the individual line; (2) the degree of asymmetry of a line decreases from the center toward the limb of the solar disc; and (3) turbulent motions 'suppress' the asymmetry.

  15. Formation of blade and slot die coated small molecule multilayers for OLED applications studied theoretically and by XPS depth profiling

    NASA Astrophysics Data System (ADS)

    Peters, Katharina; Raupp, Sebastian; Hummel, Helga; Bruns, Michael; Scharfer, Philip; Schabel, Wilhelm

    2016-06-01

    Slot die coaters especially designed for low material consumption and doctor blades were used to process small molecule solutions for organic light-emitting diodes (OLEDs). Optimum process parameters were developed for the large-scale coating techniques to generate stable single and multiple layers only a few nanometers thick. Achieving a multilayer architecture for solution-processed OLEDs is the most challenging step. X-ray photoelectron spectroscopy sputter depth profiling was performed to determine defined interfaces between coated organic layers. Commercially available small molecules NPB (N,N'-Di(1-naphthyl)-N,N'-diphenyl-(1,1'-biphenyl)-4,4'-diamine) and BAlq (Bis(8-hdroxy-2methylquinoline)-(4-phenylphenoxy)aluminum), originally developed for vacuum deposition, were used as hole, respectively electron transport material. Defined double-layers were processed with both scalable coating methods using the orthogonal solvent approach. The use of non-orthogonal solvents resulted in complete intermixing of the material. The results are explained by calculations of solubilities and simulating drying and diffusion kinetics of the small molecule solutions.

  16. Source, transport and fluxes of Amazon River particulate organic carbon: Insights from river sediment depth-profiles

    NASA Astrophysics Data System (ADS)

    Bouchez, Julien; Galy, Valier; Hilton, Robert G.; Gaillardet, Jérôme; Moreira-Turcq, Patricia; Pérez, Marcela Andrea; France-Lanord, Christian; Maurice, Laurence

    2014-05-01

    In order to reveal particulate organic carbon (POC) source and mode of transport in the largest river basin on Earth, we sampled the main sediment-laden tributaries of the Amazon system (Solimões, Madeira and Amazon) during two sampling campaigns, following vertical depth-profiles. This sampling technique takes advantage of hydrodynamic sorting to access the full range of solid erosion products transported by the river. Using the Al/Si ratio of the river sediments as a proxy for grain size, we find a general increase in POC content with Al/Si, as sediments become finer. However, the sample set shows marked variability in the POC content for a given Al/Si ratio, with the Madeira River having lower POC content across the measured range in Al/Si. The POC content is not strongly related to the specific surface area (SSA) of the suspended load, and bed sediments have a much lower POC/SSA ratio. These data suggest that SSA exerts a significant, yet partial, control on POC transport in Amazon River suspended sediment. We suggest that the role of clay mineralogy, discrete POC particles and rock-derived POC warrant further attention in order to fully understand POC transport in large rivers.

  17. Effects of thermal treatment and depth profiling analysis of solution processed bulk-heterojunction organic photovoltaic cells.

    PubMed

    Mbule, Pontsho S; Swart, Hendrik C; Ntwaeaborwa, Odireleng M

    2014-12-15

    We report the use of solution processed zinc oxide (ZnO) nanoparticles as a buffer layer inserted between the top metal electrode and the photo-active layer in bulk-heterojunction (BHJ) organic solar cell (OSC) devices. The photovoltaic properties were compared for devices annealed before (Device A) or after (Device B) the deposition of the Al top electrode. The post-annealing treatment was shown to improve the power conversion efficiency up to 2.93% and the fill factor (FF) up to 63% under AM1.5 (100mW/cm(2)) illumination. We performed the depth profile/interface analysis and elemental mapping using the time-of-flight secondary ion mass spectrometry (TOF-SIMS). Signals arising from (27)Al, (16)O, (12)C, (32)S, (64)Zn, (28)Si, (120)Sn and (115)In give an indication of successive deposition of Al, ZnO, P3HT:PCBM and PEDOT:PSS layers on ITO coated glass substrates. Furthermore, we discuss the surface imaging and visualize the chemical information on the surface of the devices. PMID:25259755

  18. Determination of hydrogen diffusion coefficients in F82H by hydrogen depth profiling with a tritium imaging plate technique

    SciTech Connect

    Higaki, M.; Otsuka, T.; Hashizume, K.; Tokunaga, K.; Ezato, K.; Suzuki, S.; Enoeda, M.; Akiba, M.

    2015-03-15

    Hydrogen diffusion coefficients in a reduced activation ferritic/martensitic steel (F82H) and an oxide dispersion strengthened F82H (ODS-F82H) have been determined from depth profiles of plasma-loaded hydrogen with a tritium imaging plate technique (TIPT) in the temperature range from 298 K to 523 K. Data on hydrogen diffusion coefficients, D, in F82H, are summarized as D [m{sup 2}*s{sup -1}] =1.1*10{sup -7}exp(-16[kJ mol{sup -1}]/RT). The present data indicate almost no trapping effect on hydrogen diffusion due to an excess entry of energetic hydrogen by the plasma loading, which results in saturation of the trapping sites at the surface and even in the bulk. In the case of ODS-F82H, data of hydrogen diffusion coefficients are summarized as D [m{sup 2}*s{sup -1}] =2.2*10{sup -7}exp(-30[kJ mol{sup -1}]/RT) indicating a remarkable trapping effect on hydrogen diffusion caused by tiny oxide particles (Y{sub 2}O{sub 3}) in the bulk of F82H. Such oxide particles introduced in the bulk may play an effective role not only on enhancement of mechanical strength but also on suppression of hydrogen penetration by plasma loading.

  19. The Relationship between the Optical Depth of the 9.7 μm Silicate Absorption Feature and Infrared Differential Extinction in Dense Clouds

    NASA Astrophysics Data System (ADS)

    Chiar, J. E.; Ennico, K.; Pendleton, Y. J.; Boogert, A. C. A.; Greene, T.; Knez, C.; Lada, C.; Roellig, T.; Tielens, A. G. G. M.; Werner, M.; Whittet, D. C. B.

    2007-09-01

    We have examined the relationship between the optical depth of the 9.7 μm silicate absorption feature (τ9.7) and the near-infrared color excess, E(J-Ks), in the Serpens, Taurus, IC 5146, Chameleon I, Barnard 59, and Barnard 68 dense clouds/cores. Our data set, based largely on Spitzer IRS spectra, spans E(J-Ks)=0.3-10 mag (corresponding to visual extinction between about 2 and 60 mag). All lines of sight show the 9.7 μm silicate feature. Unlike in the diffuse ISM where a tight linear correlation between the 9.7 μm silicate feature optical depth and the extinction (AV) is observed, we find that the silicate feature in dense clouds does not show a monotonic increase with extinction. Thus, in dense clouds, τ9.7 is not a good measure of total dust column density. With few exceptions, the measured τ9.7 values fall well below the diffuse ISM correlation line for E(J-Ks)>2 mag (AV>12 mag). Grain growth via coagulation is a likely cause of this effect.

  20. Frequency dependent crustal scattering and absorption at 5-160 Hz from coda decay observed at 2.5 Km depth

    NASA Astrophysics Data System (ADS)

    Leary, Peter; Abercrombie, Rachel

    1994-06-01

    A triaxial 10 Hz seismometer at 2.5 km depth in the Cajon Pass borehole near the San Andreas fault in southern California records shear-wave coda motion from small local events for over 20 seconds duration. The passband of recorded seismic motion is 5 Hz to 200 Hz. To measure the rate of coda energy decay as a function of frequency, we filter the vector velocity seisograms of seven events into five octave-wide frequency bands (mean frequencies approximately equals 7, 14, 28, 56 and 112 Hz) and square the filtered seisograms. The observed energy decay in each passband is well approximated by first and second order scattering plus intrinsic attenuation as formulated by Zeng at al. (1991). The fits determine two energy decay parameters expressed as inverse lengths, beta(sub scat) for scattering and beta(sub intr) for absorption. Because the source-receiver distance is less than the thickness of the upper crust and the receiver is at depth, the direct body wave is uncomplicated by refracted energy and/or surface waves and allows accurate recording of coda energy relative to source pulse energy. The coda/source energy ratio directly defines the scattering attentuation parameter b(sub scat) and voids the need for multiple offset observations.

  1. Effect of radiometric errors on accuracy of temperature-profile measurement by spectral scanning using absorption-emission pyrometry

    NASA Technical Reports Server (NTRS)

    Buchele, D. R.

    1972-01-01

    The spectral-scanning method may be used to determine the temperature profile of a jet- or rocket-engine exhaust stream by measurements of gas radiation and transmittance, at two or more wavelengths. A single, fixed line of sight is used, using immobile radiators outside of the gas stream, and there is no interference with the flow. At least two sets of measurements are made, each set consisting of the conventional three radiometric measurements of absorption-emission pyrometry, but each set is taken over a different spectral interval that gives different weight to the radiation from a different portion of the optical path. Thereby, discrimination is obtained with respect to location along the path. A given radiometric error causes an error in computed temperatures. The ratio between temperature error and radiometric error depends on profile shape, path length, temperature level, and strength of line absorption, and the absorption coefficient and its temperature dependency. These influence the choice of wavelengths, for any given gas. Conditions for minimum temperature error are derived. Numerical results are presented for a two-wavelength measurement on a family of profiles that may be expected in a practical case of hydrogen-oxygen combustion. Under favorable conditions, the fractional error in temperature approximates the fractional error in radiant-flux measurement.

  2. Nonlinear-approximation technique for determining vertical ozone-concentration profiles with a differential-absorption lidar

    NASA Astrophysics Data System (ADS)

    Kovalev, Vladimir A.; Bristow, Michael P.; McElroy, James L.

    1996-08-01

    A new technique is presented for the retrieval of ozone-concentration profiles (O 3 ) from backscattered signals obtained by a multiwavelength differential-absorption lidar (DIAL). The technique makes it possible to reduce erroneous local fluctuations induced in the ozone-concentration profiles by signal noise and other phenomena such as aerosol inhomogeneity. Before the O 3 profiles are derived, the dominant measurement errors are estimated and uncertainty boundaries for the measured profiles are established. The off- to on-line signal ratio is transformed into an intermediate function, and analytical approximations of the function are then determined. The separation of low- and high-frequency constituents of the measured ozone profile is made by the application of different approximation fits to appropriate intermediate functions. The low-frequency constituents are approximated with a low-order polynomial fit, whereas the high-frequency constituents are approximated with a trigonometric fit. The latter fit makes it possible to correct the measured O 3 profiles in zones of large ozone-concentration gradients where the low-order polynomial fit is found to be insufficient. Application of this technique to experimental data obtained in the lower troposphere shows that erroneous fluctuations induced in the ozone-concentration profile by signal noise and aerosol inhomogeneity undergo a significant reduction in comparison with the results from the conventional technique based on straightforward numerical differentiation.

  3. Nonlinear-approximation technique for determining vertical ozone-concentration profiles with a differential-absorption lidar.

    PubMed

    Kovalev, V A; Bristow, M P; McElroy, J L

    1996-08-20

    A new technique is presented for the retrieval of ozone-concentration profiles (O(3)) from backscattered signals obtained by a multiwavelength differential-absorption lidar (DIAL). The technique makes it possible to reduce erroneous local fluctuations induced in the ozone-concentration profiles by signal noise and other phenomena such as aerosol inhomogeneity. Before the O(3) profiles are derived, the dominant measurement errors are estimated and uncertainty boundaries for the measured profiles are established. The off- to on-line signal ratio is transformed into an intermediate function, and analytical approximations of the function are then determined. The separation of low- and high-frequency constituents of the measured ozone profile is made by the application of different approximation fits to appropriate intermediate functions. The low-frequency constituents are approximated with a low-order polynomial fit, whereas the high-frequency constituents are approximated with a trigonometric fit. The latter fit makes it possible to correct the measured O(3) profiles in zones of large ozone-concentration gradients where the low-order polynomial fit is found to be insufficient. Application of this technique to experimental data obtained in the lower troposphere shows that erroneous fluctuations induced in the ozone-concentration profile by signal noise and aerosol inhomogeneity undergo a significant reduction in comparison with the results from the conventional technique based on straightforward numerical differentiation. PMID:21102905

  4. Cosmogenic 10Be Depth Profile in top 560 m of West Antarctic Ice Sheet Divide Ice Core

    NASA Astrophysics Data System (ADS)

    Welten, K. C.; Woodruff, T. E.; Caffee, M. W.; Edwards, R.; McConnell, J. R.; Bisiaux, M. M.; Nishiizumi, K.

    2009-12-01

    Concentrations of cosmogenic 10Be in polar ice samples are a function of variations in solar activity, geomagnetic field strength, atmospheric mixing and annual snow accumulation rates. The 10Be depth profile in ice cores also provides independent chronological markers to tie Antarctic to Greenland ice cores and to tie Holocene ice cores to the 14C dendrochronology record. We measured 10Be concentrations in 187 samples from depths of 0-560 m of the main WAIS Divide core, WDC06A. The ice samples are typically 1-2 kg and represent 2-4 m of ice, equivalent to an average temporal resolution of ~12 years, based on the preliminary age-depth scale proposed for the WDC core, (McConnell et al., in prep). Be, Al and Cl were separated using ion exchange chromatography techniques and the 10Be concentrations were measured by accelerator mass spectrometry (AMS) at PRIME lab. The 10Be concentrations range from 8.1 to 19.1 x 10^3 at/g, yielding an average of (13.1±2.1) x 10^3 at/g. Adopting an average snow accumulation rate of 20.9 cm weq/yr, as derived from the age-depth scale, this value corresponds to an average 10Be flux of (2.7±0.5) x 10^5 atoms/yr/cm2. This flux is similar to that of the Holocene part of the Siple Dome (Nishiizumi and Finkel, 2007) and Dome Fuji (Horiuchi et al. 2008) ice cores, but ~30% lower than the value of 4.0 x 10^5 atoms/yr/cm2 for GISP2 (Finkel and Nishiizumi, 1997). The periods of low solar activity, known as Oort, Wolf, Spörer, Maunder and Dalton minima, show ~20% higher 10Be concentrations/fluxes than the periods of average solar activity in the last millennium. The maximum 10Be fluxes during some of these periods of low solar activity are up to ~50% higher than average 10Be fluxes, as seen in other polar ice cores, which makes these peaks suitable as chronologic markers. We will compare the 10Be record in the WAIS Divide ice core with that in other Antarctic as well as Greenland ice cores and with the 14C treering record. Acknowledgment. This

  5. NO2 Profile Retrieval using airborne multi axis UV-visible skylight absorption measurements over central Europe

    NASA Astrophysics Data System (ADS)

    Bruns, M.; Buehler, S. A.; Burrows, J. P.; Richter, A.; Rozanov, A.; Wang, P.; Heue, K.-P.; Platt, U.; Pundt, I.; Wagner, T.

    2006-01-01

    A recent development in ground-based remote sensing of atmospheric constituents by UV/visible absorption measurements of scattered light is the simultaneous use of several directions with small elevation angles in addition to the traditional zenith-sky pointing. The different light paths through the atmosphere enable the vertical distribution of some atmospheric absorbers such as NO2, BrO or O3 to be retrieved. In this study, the amount of profile information that can be retrieved from such measurements on aircraft is investigated for the trace gas NO2. A Sensitivity study on synthetic data is performed for a combination of four lines of sight (LOS) (0° (nadir), 88°, 92°, and 180° (zenith)) and three wavelength regions [center wavelengths: 362.5 nm, 437.5 nm, and 485.0 nm]. This investigation demonstrates the potential of this LOS/wavelengths setup to retrieve a significant amount of profile information from airborne multiaxis differential optical absorption spectrometer (AMAXDOAS) measurements with a vertical resolution of 3.0 to 4.5 km in the lower troposphere and 2.0 to 3.5 km near flight altitude. Above 13 km the profile information content of AMAXDOAS measurements is sparse. Further, retrieved profiles with a significant amount (up to 3.2 ppbv) of NO2 in the boundary layer over the Po-valley (Italy) are presented. Airborne multiaxis measurements are thus a promising tool for atmospheric studies in the troposphere.

  6. Explaining discrepant depth profiles of {sup 234}U/{sup 238}U and {sup 230}Th{sub exc} in Mn-crusts

    SciTech Connect

    Neff, U.; Bollhoefer, A.; Frank, N.; Mangini, A.

    1999-08-01

    Manganese encrustations are an important archive for the reconstruction of deep ocean circulation in the past. However, because of discordant growth rates derived from the decrease of the activity ratios of {sup 234}U/{sup 238}U and of {sup 230}Th{sub exc} with depth, their dating via the measurement of depth profiles of {sup 230}Th and {sup 231}Pa has been recently put into question (Chabaux et al., 1997). In this study the authors present high precision depth profiles of uranium and thorium isotopes (TIMS) of a hydrogenous Mn-crust from the South China Sea. Indeed, the depth profiles of {sup 234}U/{sup 238}U and {sup 238}Th{sub exc} deliver very different growth rates of 8.80 {+-} 1.20 and 2.64 {+-} 0.12 mm/Ma, respectively. The authors solve this discrepancy with a simple model which assumes exchange of uranium adsorbed in the Mn-crust with uranium dissolved in the pore water. The best agreement to the data is obtained applying an exchange coefficient of 5 {times} 10{sup {minus}6} [a{sup {minus}1}]. Application of this model to the data set of Chabaux et al. (1997), reproduces very well their profiles of the {delta}{sup 234}U. The authors conclude that {sup 234}U/{sup 238}U dating of Mn-encrustations is not reliable because of open-system conditions for uranium.

  7. Auger electron spectroscopy study and depth profile analyses of the CaS:Eu2+ pulsed laser deposited thin luminescent films

    NASA Astrophysics Data System (ADS)

    Nyenge, R. L.; Swart, H. C.; Ntwaeaborwa, O. M.

    2016-06-01

    This paper presents the results of a study of the chemical composition, depth profile analyses of pulsed laser deposited CaS:Eu2+ thin films grown at different substrate temperatures. Using Auger electron spectroscopy, we have shown that the thin film grown in an argon atmosphere shows sulfur deficiency as the substrate temperature is increased from 200 to 650 °C.

  8. Applications of principal component analysis to breath air absorption spectra profiles classification

    NASA Astrophysics Data System (ADS)

    Kistenev, Yu. V.; Shapovalov, A. V.; Borisov, A. V.; Vrazhnov, D. A.; Nikolaev, V. V.; Nikiforova, O. Y.

    2015-12-01

    The results of numerical simulation of application principal component analysis to absorption spectra of breath air of patients with pulmonary diseases are presented. Various methods of experimental data preprocessing are analyzed.

  9. Determination of particle-induced structural disorder depth profile in crystals using the grazing-angle incidence hard x-ray backscattering diffraction technique

    NASA Astrophysics Data System (ADS)

    Bezirganyan, Hakob (Jacob P.; Bezirganyan, Siranush E.; Bezirganyan, Petros H., Jr.; Bezirganyan, Hayk H., Jr.

    2011-12-01

    In this theoretical paper, we propose an x-ray imaging method for determination of particle-induced structural disorder depth profile in the crystalline materials based on the extremely sensitive, high-resolution, and non-destructive grazing-angle incidence hard x-ray backscattering diffraction technique. A peculiar value of the Bragg angle is discovered within the specular beam suppression angular region for which the curve of x-ray reflectivity is very close to the profile of the corresponding structural disorder. The coincidence presents a unique opportunity for the direct registration of the structural disorder depth profile in particle-irradiated crystals. This paper is dedicated to Professor Dr Petros H Bezirganyan on the occasion of his 95th birthday on 15th December 2011.

  10. Aerosols in GEOS-5: simulations of the UV Aerosol Index and the Aerosol Absorption Optical Depth and comparisons with OMI retrievals.

    NASA Astrophysics Data System (ADS)

    Buchard-Marchant, Virginie; da Silva, Arlindo; Colarco, Peter; Darmenov, Anton; Govindaraju, Ravi

    2013-04-01

    GEOS-5 is the latest version of the NASA Global Modeling and Assimilation Office (GMAO) earth system model. GEOS-5 contains components for atmospheric circulation and composition (including data assimilation), ocean circulation and biogeochemistry, and land surface processes. In addition to traditional meteorological parameters, GEOS-5 includes modules representing the atmospheric composition, most notably aerosols and tropospheric/stratospheric chemical constituents, taking explicit account of the impact of these constituents on the radiative processes of the atmosphere. The assimilation of Aerosol Optical Depth (AOD) in GEOS-5 involves very careful cloud screening and homogenization of the observing system by means of a Neural Net scheme that translates MODIS radiances into AERONET calibrated AOD. These measurements are further quality controlled using an adaptive buddy check scheme, and assimilated using the Local Displacement Ensemble (LDE) methodology. For this analysis, GEOS-5 runs at a nominal 50km horizontal resolution with 72 vertical layers (top at ~85km). GEOS-5 is driven by daily biomass burning emissions derived from MODIS fire radiative power retrievals. We present a summary of our efforts to simulate the UV Aerosol Index (AI) at 354 nm from aerosol simulations by performing a radiative transfer calculation. We have compared model produced AI with the corresponding OMI measurements, identifying regions where the model representation of absorbing aerosols were deficient. Separately, model derived Absorption Aerosol Optical Depth (AAOD) is compared with OMI retrievals. Making use of CALIPSO measurements we have also investigated the impact of the altitude of the aerosol layer on OMI derived AI trying to ascertain misplacement of plume height by the model.

  11. NO2 Profile retrieval using airborne multi axis UV-visible skylight absorption measurements over central Europe

    NASA Astrophysics Data System (ADS)

    Bruns, M.; Buehler, S. A.; Burrows, J. P.; Richter, A.; Rozanov, A.; Wang, P.; Heue, K. P.; Platt, U.; Pundt, I.; Wagner, T.

    2006-07-01

    A recent development in ground-based remote sensing of atmospheric constituents by UV/visible absorption measurements of scattered light is the simultaneous use of several directions with small elevation angles in addition to the traditional zenith-sky pointing. The different light paths through the atmosphere enable the vertical distribution of some atmospheric absorbers such as NO2, BrO or O3 to be retrieved. In this study, the amount of profile information that can be retrieved from such measurements on aircraft is investigated for the trace gas NO2. A Sensitivity study on synthetic data is performed for a combination of four lines of sight (LOS) (0°(nadir), 88°, 92°, and 180° (zenith)) and three wavelength regions [center wavelengths: 362.5 nm, 437.5 nm, and 485.0 nm]. The method used in this work is a combination of two previously established methods described in Petritoli et al. (2002) and Wang et al. (2004). The investigation presented here demonstrates the potential of this LOS/wavelengths setup to retrieve a significant amount of profile information from airborne multiax is differential optical absorption spectrometer (AMAXDOAS) measurements with a vertical resolution of 3.0 to 4.5 km in the lower troposphere and 2.0 to 3.5 km near flight altitude. Above 13 km the profile information content of AMAXDOAS measurements is sparse. The retrieval algorithm used in this work is the AMAXDOAS profile retrievalalgorithm (APROVAL). Further, retrieved profiles with a significant amount (up to 3.2 ppbv) of NO2 in the boundary layer over the Po-valley (Italy) are presented. Airborne multiaxis measurements are thus a promising tool for atmospheric studies in the troposphere.

  12. Possibilities of LA-ICP-MS technique for the spatial elemental analysis of the recent fish scales: Line scan vs. depth profiling

    NASA Astrophysics Data System (ADS)

    Holá, Markéta; Kalvoda, Jiří; Nováková, Hana; Škoda, Radek; Kanický, Viktor

    2011-01-01

    LA-ICP-MS and solution based ICP-MS in combination with electron microprobe are presented as a method for the determination of the elemental spatial distribution in fish scales which represent an example of a heterogeneous layered bone structure. Two different LA-ICP-MS techniques were tested on recent common carp ( Cyprinus carpio) scales: A line scan through the whole fish scale perpendicular to the growth rings. The ablation crater of 55 μm width and 50 μm depth allowed analysis of the elemental distribution in the external layer. Suitable ablation conditions providing a deeper ablation crater gave average values from the external HAP layer and the collagen basal plate. Depth profiling using spot analysis was tested in fish scales for the first time. Spot analysis allows information to be obtained about the depth profile of the elements at the selected position on the sample. The combination of all mentioned laser ablation techniques provides complete information about the elemental distribution in the fish scale samples. The results were compared with the solution based ICP-MS and EMP analyses. The fact that the results of depth profiling are in a good agreement both with EMP and PIXE results and, with the assumed ways of incorporation of the studied elements in the HAP structure, suggests a very good potential for this method.

  13. Influence of the vertical absorption profile of mixed Asian dust plumes on aerosol direct radiative forcing over East Asia

    NASA Astrophysics Data System (ADS)

    Noh, Young Min; Lee, Kwonho; Kim, Kwanchul; Shin, Sung-Kyun; Müller, Detlef; Shin, Dong Ho

    2016-08-01

    We estimate the aerosol direct radiative forcing (ADRF) and heating rate profiles of mixed East Asian dust plumes in the solar wavelength region ranging from 0.25 to 4.0 μm using the Santa Barbara Discrete Ordinate Atmospheric Radiative Transfer (SBDART) code. Vertical profiles of aerosol extinction coefficients and single-scattering albedos (SSA) were derived from measurements with a multi-wavelength Raman lidar system. The data are used as input parameters for our radiative transfer calculations. We considered four cases of radiative forcing in SBDART: 1. dust, 2. pollution, 3. mixed dust plume and the use of vertical profiles of SSA, and 4. mixed dust plumes and the use of column-averaged values of SSA. In our sensitivity study we examined the influence of SSA and aerosol layer height on our results. The ADRF at the surface and in the atmosphere shows a small dependence on the specific shape of the aerosol extinction vertical profile and its light-absorption property for all four cases. In contrast, at the top of the atmosphere (TOA), the ADRF is largely affected by the vertical distribution of the aerosols extinction. This effect increases if the light-absorption capacity (decrease of SSA) of the aerosols increases. We find different radiative effects in situations in which two layers of aerosols had different light-absorption properties. The largest difference was observed at the TOA for an absorbing aerosol layer at high altitude in which we considered in one case the vertical profile of SSA and in another case the column-averaged SSA only. The ADRF at the TOA increases when the light-absorbing aerosol layer is located above 3 km altitude. The differences between height-resolved SSA, which can be obtained from lidar data, and total layer-mean SSA indicates that the use of a layer-mean SSA can be rather misleading as it can induce a large error in the calculation of the ADRF at the TOA, which in turn may cause errors in the vertical profiles of heating rates.

  14. A depth-dependent profile of the lipid conformation and lateral packing order of the stratum corneum in vivo measured using Raman microscopy.

    PubMed

    Choe, ChunSik; Lademann, Jürgen; Darvin, Maxim E

    2016-03-21

    The intercellular lipid structure of the stratum corneum (SC) plays a key role in skin barrier function. A depth profile of the intercellular lipid conformation and the lipid lateral packing order were measured in vivo in the human SC using confocal Raman microscopy. The depth profiles of the 2880 cm(-1)/2850 cm(-1) peak ratio intensity, which represent the C-H stretching and lateral packing order of lipids, and the 1080 cm(-1)/(1130 cm(-1) + 1060 cm(-1)) peak ratio, which represents the C-C skeleton vibration and trans-gauche conformation order of lipids, were investigated. The influence of keratin on the lipid peaks at 2850 cm(-1) and 2880 cm(-1) was excluded by the developed mathematical algorithm. The results show that the trans-conformation and lateral packing order of the intercellular lipids reach their maximum value in the SC at 20-40% of its depth and then decrease towards the stratum granulosum. These results show that at a depth of 20-40% (normally corresponding to a depth of 4-8 μm) the SC exhibits the most ordered lipids and therefore the highest skin barrier function. The lateral packing of lipids is more disordered on the surface and in the deeper parts of the SC, which may be associated with a reduced skin barrier function. PMID:26855232

  15. Quantification of ammonia oxidation rates and the distribution of ammonia-oxidizing Archaea and Bacteria in marine sediment depth profiles from Catalina Island, California

    PubMed Central

    Beman, J. M.; Bertics, Victoria J.; Braunschweiler, Thomas; Wilson, Jesse M.

    2012-01-01

    Microbial communities present in marine sediments play a central role in nitrogen biogeochemistry at local to global scales. Along the oxidation–reduction gradients present in sediment profiles, multiple nitrogen cycling processes (such as nitrification, denitrification, nitrogen fixation, and anaerobic ammonium oxidation) are active and actively coupled to one another – yet the microbial communities responsible for these transformations and the rates at which they occur are still poorly understood. We report pore water geochemical (O2, NH4+, and NO3−) profiles, quantitative profiles of archaeal and bacterial amoA genes, and ammonia oxidation rate measurements, from bioturbated marine sediments of Catalina Island, California. Across triplicate sediment cores collected offshore at Bird Rock (BR) and within Catalina Harbor (CH), oxygen penetration (0.24–0.5 cm depth) and the abundance of amoA genes (up to 9.30 × 107 genes g–1) varied with depth and between cores. Bacterial amoA genes were consistently present at depths of up to 10 cm, and archaeal amoA was readily detected in BR cores, and CH cores from 2008, but not 2007. Although detection of DNA is not necessarily indicative of active growth and metabolism, ammonia oxidation rate measurements made in 2008 (using isotope tracer) demonstrated the production of oxidized nitrogen at depths where amoA was present. Rates varied with depth and between cores, but indicate that active ammonia oxidation occurs at up to 10 cm depth in bioturbated CH sediments, where it may be carried out by either or both ammonia-oxidizing archaea and bacteria. PMID:22837756

  16. Gelled electrolytes for use in absorptive glass mat valve-regulated lead-acid (AGM VRLA) batteries working under 100% depth of discharge conditions

    NASA Astrophysics Data System (ADS)

    Tantichanakul, Titiporn; Chailapakul, Orawon; Tantavichet, Nisit

    2011-10-01

    Gelled electrolytes prepared from fumed silica for use in absorptive glass mat valve-regulated lead-acid (AGM VRLA) batteries and the effect of veratraldehyde addition on the electrochemical behavior and performance of AGM VRLA batteries are investigated. Cyclic voltammetry is used to investigate differences in the electrochemical behaviors of nongelled and gelled electrolytes and between gelled electrolytes with and without veratraldehyde. Battery performance is tested under 100% depth of discharge (100% DoD) conditions at both low- (0.1 C) and high- (1 C) rate discharges. The addition of silica or veratraldehyde does not affect the main reaction of the lead-acid batteries but tends to suppress the hydrogen evolution reaction. AGM VRLA batteries with gelled electrolytes have a higher discharge capacity and longer cycle life than the conventional nongel AGM VRLA batteries. The addition of 0.005% (w/v) veratraldehyde further improves battery performance, but higher (0.01%, w/v) veratraldehyde concentrations reduce it and correlate with the enhanced growth of lead sulfate crystals. The AGM VRLA battery prepared from a gelled electrolyte containing 0.005% (w/v) veratraldehyde provides the best battery performance in every operating temperature studied (0-60 °C).

  17. Detrital zircon LASS-ICP-MS petrochronologic depth profiling for determining source-to-sink relationships in the Central Alps.

    NASA Astrophysics Data System (ADS)

    Anfinson, O. A.; Stockli, D. F.; Stockli, L.; Malusa', M. G.

    2015-12-01

    Laser Ablation-Split Stream Depth Profiling (LASS-DP) ICP-MS petrochronology of detrital zircon (DZ) from Oligocene-Miocene strata in the Molasse and Northern Apennines showcases, in the light of the well-constrained depositional history of these successions, the advantages of this novel approach compared to traditional single and split-stream detrital zircon techniques in elucidating sediment provenance and source-to-sink relationships. While DZ U-Pb data from Oligocene-Miocene strata deposited in both the Molasse and Northern Apennines document shifts in the relative abundance of Cadomian, Caledonian, Variscan and Alpine aged detrital zircon, the source regions remain ambiguous due to non-diagnostic crystallization ages, leading to minimal zircon age variability. In contrast, DZ LASS-DP-ICP-MS petrochronology allows for the simultaneous recovery of multiple U-Pb ages and corresponding geochemical data, and thus dramatically increases our ability to resolve the petrogenetic history of individual DZ grains. The technique shows the immense power of determining the growth history of single DZ grains (rim to core relationships) and identifying/resolving the presence and age of thin magmatic/metamorphic overgrowths. Rupelian turbidites in the Apenninic foredeep exhibit a DZ population with consistent <5 mm Cretaceous metamorphic overgrowths that would likely not be resolved as a coherent population in polished sections. LASS-DP ICP-MS analysis of Caledonian and Variscan detrital zircon populations from the Molasse Basin show a distinct shift in rim-core age pairs in individual zircons that point to the erosion of different source during progressive Alpine unroofing. The geochemical data confirm a crustally derived magmatic source for the majority of the detrital zircon grains within the basin. While this technique, in comparison to traditional polished mounts, might underrepresent older core ages, this slight bias is clearly offset by the better definition and

  18. Computer Program for Calculation of a Gas Temperature Profile by Infrared Emission: Absorption Spectroscopy

    NASA Technical Reports Server (NTRS)

    Buchele, D. R.

    1977-01-01

    A computer program to calculate the temperature profile of a flame or hot gas was presented in detail. Emphasis was on profiles found in jet engine or rocket engine exhaust streams containing H2O or CO2 radiating gases. The temperature profile was assumed axisymmetric with an assumed functional form controlled by two variable parameters. The parameters were calculated using measurements of gas radiation at two wavelengths in the infrared. The program also gave some information on the pressure profile. A method of selection of wavelengths was given that is likely to lead to an accurate determination of the parameters. The program is written in FORTRAN IV language and runs in less than 60 seconds on a Univac 1100 computer.

  19. Depth profiles of the Doppler-broadening S parameter for polymers obtained with two measuring patterns: The role of accumulated charges

    NASA Astrophysics Data System (ADS)

    Yang, J.; Zhang, P.; Lu, E. Y.; Cao, X. Z.; Yu, R. S.; Wang, B. Y.

    2014-03-01

    Depth profiles of Doppler broadening S parameter for oxygen containing polymer polycarbonate (PC), fluoropolymer poly (tetrafluoroethylene) (PTFE) and chlorine containing polymer polyvinylchloride-unplasticized (UPVC) were obtained with two measuring patterns, i.e. energy increase pattern and energy decrease pattern. The two curves can't coincide with each other for that a trough appeared between 1 and 5 keV in the curve obtained with energy decrease pattern. It was found that charges induced by high energy incident positrons greatly influenced the annihilation of low energy incident positrons, while charges induced by low energy incident positrons showed little influence on the annihilation of high energy incident positrons. With energy increase measuring pattern, charges induced by low energy incident positrons showed little influence on the annihilation of later incident high energy positrons, thus the measurement can give the depth profile of S parameter in polymer as it was.

  20. Far wing depolarization of light - Generalized absorption profiles. [in laser fluorescence spectroscopy of Sr vapor

    NASA Technical Reports Server (NTRS)

    Thomann, P.; Burnett, K.; Cooper, J.

    1981-01-01

    An absorption (and/or emission) event which takes place during a strong collision is called a 'correlated event'. It is discussed how correlated events affect the far red wing depolarization of fluorescence. Attention is given to an atomic vapor which is irradiated by linearly polarized light of a frequency on the red side of the resonance line. Two limiting cases are considered, corresponding to excitation in the impact region and in the quasi-static wing. In the quasi-static wing, absorption of a photon followed by fluorescence (rather than Rayleigh scattering), occurs mostly during a collision. Correlated events dominate the scattering process. Expressions derived for the polarization of the fluorescent light are applied to far red wing depolarization. It is found that the polarization of the fluorescent light does not go to zero in the far wing, but depends crucially on the detailed nature of the anisotropy in the long-range part of the interatomic potential.

  1. In situ depth profiling of 137Cs contamination in soils at the Idaho National Engineering and Environmental Laboratory.

    PubMed

    Oertel, Christopher P; Giles, John R; Thompson, Kenneth C; Wells, Richard P

    2004-12-01

    Preremediation characterization of Cs contamination in soils was conducted at the Auxiliary Reactor Area (ARA)-23 Comprehensive Environmental Response, Compensation, and Liability Act site, located at the Idaho National Engineering and Environmental Laboratory (INEEL). Characterization activities included verification of the lateral extent of the contaminated area using the INEEL vehicle-mounted Global Positioning Radiometric Scanner. The vertical extent of the contamination in select areas of the site was evaluated with an in situ gamma-ray spectrometer, and depth discrete samples were collected at 5-cm depth intervals down to a depth of 20.3 cm. A comparison was made between the depth distribution data from the in situ spectrometric measurements and the physical, depth discrete samples. The results of the study and of the aforementioned comparison indicate that use of in situ high-purity germanium (HPGe) detectors during the remediation of the ARA-23 site will aid in directing the depth of excavation, thereby helping to (a) minimize the amount of soils excavated and removed for disposal, and (b) reduce overall project costs. PMID:15545774

  2. A Ground-Based Profiling Differential Absorption LIDAR System for Measuring CO2 in the Planetary Boundary Layer

    NASA Technical Reports Server (NTRS)

    Andrews, Arlyn E.; Burris, John F.; Abshire, James B.; Krainak, Michael A.; Riris, Haris; Sun, Xiao-Li; Collatz, G. James

    2002-01-01

    Ground-based LIDAR observations can potentially provide continuous profiles of CO2 through the planetary boundary layer and into the free troposphere. We will present initial atmospheric measurements from a prototype system that is based on components developed by the telecommunications industry. Preliminary measurements and instrument performance calculations indicate that an optimized differential absorption LIDAR (DIAL) system will be capable of providing continuous hourly averaged profiles with 250m vertical resolution and better than 1 ppm precision at 1 km. Precision increases (decreases) at lower (higher) altitudes and is directly proportional to altitude resolution and acquisition time. Thus, precision can be improved if temporal or vertical resolution is sacrificed. Our approach measures absorption by CO2 of pulsed laser light at 1.6 microns backscattered from atmospheric aerosols. Aerosol concentrations in the planetary boundary layer are relatively high and are expected to provide adequate signal returns for the desired resolution. The long-term goal of the project is to develop a rugged, autonomous system using only commercially available components that can be replicated inexpensively for deployment in a monitoring network.

  3. Depth profiles of radioactive cesium in soil using a scraper plate over a wide area surrounding the Fukushima Dai-ichi Nuclear Power Plant, Japan.

    PubMed

    Matsuda, Norihiro; Mikami, Satoshi; Shimoura, Susumu; Takahashi, Junko; Nakano, Masakazu; Shimada, Kiyotaka; Uno, Kiichiro; Hagiwara, Shigetomo; Saito, Kimiaki

    2015-01-01

    During the Fukushima Dai-ichi Nuclear Power Plant (NPP) accident, radioactive cesium was released in the environment and deposited on the soils. Depth profiles of radioactive cesium in contaminated soils provide useful information not only for radiation protection and decontamination operations but also for geoscience and radioecology studies. Soil samples were collected using a scraper plate three times between December 2011 and December 2012 at 84 or 85 locations within a 100-km radius of the Fukushima Dai-ichi NPP. In most of the obtained radioactive cesium depth profiles, it was possible to fit the concentration to a function of mass depth as either an exponential or hyperbolic secant function. By using those functions, following three parameters were estimated: (i) relaxation mass depth β (g cm(-2)), (ii) effective relaxation mass depth βeff (g cm(-2)), which is defined for a hyperbolic secant function as the relaxation mass depth of an equivalent exponential function giving the same air kerma rate at 1 m above the ground as the inventory, and (iii) 1/10 depth L1/10 (cm), at which the soil contains 90% of the inventory. The average β value (wet weight) including ones by hyperbolic secant function in December 2012, was 1.29 times higher than that in December 2011. In fact, it was observed that depth profiles at some study sites deviated from the typical exponential distributions over time. These results indicate the gradual downward migration of radioactive cesium in the soils. The L1/10 values in December 2012 were summarized and presented on a map surrounding the Fukushima Dai-ichi NPP, and the average value of L1/10 was 3.01 cm (n = 82) at this time. It was found that radioactive cesium remained within 5 cm of the ground surface at most study sites (71 sites). The sech function can also be used to estimate the downward migration rate V (kg m(-2) y(-1)). The V values in December 2012 (n = 25) were in good agreement with those found by a

  4. Depth profile reconstructions of electronic transport properties in H{sup +} MeV-energy ion-implanted n-Si wafers using photocarrier radiometry

    SciTech Connect

    Tai, Rui; Wang, Chinhua Hu, Jingpei; Mandelis, Andreas

    2014-07-21

    A depth profiling technique using photocarrier radiometry (PCR) is demonstrated and used for the reconstruction of continuously varying electronic transport properties (carrier lifetime and electronic diffusivity) in the interim region between the ion residence layer and the bulk crystalline layer in H{sup +} implanted semiconductor wafers with high implantation energies (∼MeV). This defect-rich region, which is normally assumed to be part of the homogeneous “substrate” in all existing two- and three-layer models, was sliced into many virtual thin layers along the depth direction so that the continuously and monotonically variable electronic properties across its thickness can be considered uniform within each virtual layer. The depth profile reconstruction of both carrier life time and diffusivity in H{sup +} implanted wafers with several implantation doses (3 × 10{sup 14}, 3 × 10{sup 15}, and 3 × 10{sup 16} cm{sup −2}) and different implantation energies (from 0.75 to 2.0 MeV) is presented. This all-optical PCR method provides a fast non-destructive way of characterizing sub-surface process-induced electronic defect profiles in devices under fabrication at any intermediate stage before final metallization and possibly lead to process correction and optimization well before electrical testing and defect diagnosis becomes possible.

  5. Determination of the depth profile distribution of guest species in microporous materials using the voltammetry of immobilized particles methodology: application to lapachol attachment to palygorskite and kaolinite.

    PubMed

    Doménech-Carbó, Antonio; Martini, Mariele; Valle-Algarra, Francisco Manuel

    2014-09-21

    A model for determining the in-depth profile distribution of electroactive species hosted in inorganic microporous matrixes using the voltammetry of immobilized particles methodology is described. The method, based on the analysis of cyclic voltammetric data at different potential scan rates, allows us to determine the in-depth profile variation of the concentration of electroactive guest species as well as the evaluation of the (oxidized form)/(reduced form) concentration ratio in cases where two oxidation states of the electroactive species coexist. The application to Maya blue-type materials prepared from lapachol, a naphtoquinonic dye, and palygorskite and kaolinite clays is reported. The determination of the in-depth distribution of guest molecules is not easy due to the heterogeneity of the clay particle size distribution and the appearance of cyclization and redox tuning reactions. Electrochemical data revealed differences in the in-depth distribution of the dye molecules in the grains of the channelled (palygorskite) and the laminar (kaolinite) clays that suggest that lapachol compounds can ingress into the channels of the palygorskite framework whereas remain externally adsorbed onto the kaolinite crystals. PMID:25093430

  6. Distribution and depth profiles of polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans, and polychlorinated biphenyls in sediment collected from offshore waters of Central Vietnam.

    PubMed

    Tri, Tran Manh; Anh, Hoang Quoc; Tham, Trinh Thi; Van Quy, Tran; Long, Nguyen Quang; Nhung, Dao Thi; Nakamura, Masafumi; Nishida, Masayo; Maeda, Yasuaki; Van Boi, Luu; Minh, Tu Binh

    2016-05-15

    Concentrations of PCBs and OCPs were measured in 35 surface sediment samples collected from offshore waters of Central Vietnam. The mean concentrations of PCBs, HCHs, and DDTs in surface sediments were 86.5, 37.0, and 44.5pgg(-1), respectively. Additionally, nine PCDDs, eleven PCDFs, and twelve dl-PCBs were also examined in 19 sediment core samples collected from five locations. Concentration of PCDDs, PCDFs, and dl-PCBs ranged from 200 to 460, 0.39 to 2.9, and 1.6 to 22pgg(-1), respectively. OCDD was detected at the highest concentration, ranged from 100 to 300pgg(-1). Generally, the concentrations of PCDD/Fs at shallower depths were higher, meanwhile the depth profiles of dl-PCBs in sediment cores were different than the depth profiles of PCDD/Fs. The results suggest that the pollution of PCBs might be from many different sources leading to the variation between depths. PMID:26994835

  7. Depth profiling of the elemental surface composition of the oral microorganism S. salivarius HB and fibrillar mutants by X-ray photoelectron spectroscopy.

    PubMed

    van der Mei, H C; Handley, P S; Busscher, H J

    1992-02-01

    X-ray photoelectron spectroscopy (XPS) on microbial cell surfaces requires freeze-drying of cells, and as a result, the cell surface appendages flatten out on the cell surface and form a collapsed fibrillar mass. At present, it is unclear how the density, length and composition of these fibrils influence the elemental surface composition as probed by XPS. The sampling depth of XPS can be varied by changing the electron take-off angle. In this article, we made a depth profiling of the collapsed fibrillar mass of Streptococcus salivarius HB and fibril-deficient mutants by angle-dependent XPS. Methylamine tungstate negative staining and ruthenium red staining followed by sectioning revealed distinct classes of fibrils with various lengths on each of the strains. Interpretation of the angle dependence of the oxygen/carbon (O/C) and phosphorus/carbon (P/C) surface concentration ratios of these strains was difficult. However, the angle dependence of the nitrogen/carbon (N/C) surface concentration ratio could be fully interpreted: N/C did not vary with sampling depth on a bald strain, S. salivarius HBC12 and on S. salivarius HB7, a strain with a dense array of fibrils of uniform length. N/C decreased with sampling depth in case of a sparsely fibrillated strain, S. salivarius HBV51 and eventually reached the value observed for the bald strain, HBC12. A high N/C at small sampling depth was observed for S. salivarius HB with protruding, protein rich fibrils. We conclude that elemental depth profiling of microbial cell surfaces by XPS can be interpreted to coincide with structural and biochemical information on the cell surface as obtained by electron microscopy and can therefore be considered as a useful technique to study structural features of cell surfaces in combination with electron microscopy. PMID:1284785

  8. Complex X-ray Absorption and the Fe K(alpha) Profile in NGC 3516

    NASA Technical Reports Server (NTRS)

    Turner, T. J.; Kraemer, S. B.; George, I. M.; Reeves, J. N.; Botorff, M. C.

    2004-01-01

    We present data from simultaneous Chandra, XMM-Newton and BeppoSAX observations of the Seyfert 1 galaxy NGC 3516, taken during 2001 April and November. We have investigated the nature of the very flat observed X-ray spectrum. Chandra grating data show the presence of X-ray absorption lines, revealing two distinct components of the absorbing gas, one which is consistent with our previous model of the UV/X-ray absorber while the other, which is outflowing at a velocity of approximately 1100 kilometers per second, has a larger column density and is much more highly ionized. The broad-band spectral characteristics of the X-ray continuum observed with XMM during 2001 April, reveal the presence of a third layer of absorption consisting of a very large column (approximately 2.5 x 10(exp 23) per square centimeter) of highly ionized gas with a covering fraction approximately 50%. This low covering fraction suggests that the absorber lies within a few 1t-days of the X-ray source and/or is filamentary in structure. Interestingly, these absorbers are not in thermal equilibrium with one another. The two new components are too highly ionized to be radiatively accelerated, which we suggest is evidence for a hydromagnetic origin for the outflow. Applying our model to the November dataset, we can account for the spectral variability primarily by a drop in the ionization states of the absorbers, as expected by the change in the continuum flux. When this complex absorption is accounted for we find the underlying continuum to be typical of Seyfert 1 galaxies. The spectral curvature attributed to the high column absorber, in turn, reduces estimates of the flux and extent of any broad Fe emission line from the accretion disk.

  9. Laboratory Measurements of the 940, 1130, and 1370 nm Water Vapor Absorption Band Profiles

    NASA Technical Reports Server (NTRS)

    Giver, Lawrence P.; Gore, Warren J.; Pilewskie, P.; Freedman, R. S.; Chackerian, C., Jr.; Varanasi, P.

    2001-01-01

    We have used the solar spectral flux radiometer (SSFR) flight instrument with the Ames 25 meter base-path White cell to obtain about 20 moderate resolution (8 nm) pure water vapor spectra from 650 to 1650 nm, with absorbing paths from 806 to 1506 meters and pressures up to 14 torr. We also obtained a set at 806 meters with several different air-broadening pressures. Model simulations were made for the 940, 1130, and 1370 nm absorption bands for some of these laboratory conditions using the Rothman, et al HITRAN-2000 linelist. This new compilation of HITRAN includes new intensity measurements for the 940 nm region. We compared simulations for our spectra of this band using HITRAN-2000 with simulations using the prior HITRAN-1996. The simulations of the 1130 nm band show about 10% less absorption than we measured. There is some evidence that the total intensity of this band is about 38% stronger than the sum of the HITRAN line intensities in this region. In our laboratory conditions the absorption depends approximately on the square root of the intensity. Thus, our measurements agree that the band is stronger than tabulated in HITRAN, but by about 20%, substantially less than the published value. Significant differences have been shown between Doppler-limited resolution spectra of the 1370 nm band obtained at the Pacific Northwest National Laboratory and HITRAN simulations. Additional new intensity measurements in this region are continuing to be made. We expect the simulations of our SSFR lab data of this band will show the relative importance of improving the HITRAN line intensities of this band for atmospheric measurements.

  10. Differential absorption and Raman lidar for water vapor profile measurements - A review

    NASA Technical Reports Server (NTRS)

    Grant, William B.

    1991-01-01

    Differential absorption lidar and Raman lidar have been applied to the range-resolved measurements of water vapor density for more than 20 years. Results have been obtained using both lidar techniques that have led to improved understanding of water vapor distributions in the atmosphere. This paper reviews the theory of the measurements, including the sources of systematic and random error; the progress in lidar technology and techniques during that period, including a brief look at some of the lidar systems in development or proposed; and the steps being taken to improve such lidar systems.

  11. Depth profiles of temperature, specific conductance and oxygen concentration in Lake Powell, Arizona-Utah, 1992-95

    USGS Publications Warehouse

    Marzolf, G. Richard; Hart, Robert J.; Stephens, Doyle W.

    1998-01-01

    The depth distribution of temperature in lakes and reservoirs establishes vertical-density gradients that regulate the distribution of a wide array of chemical and biological features. In Lake Powell, the depth at which inflowing river water enters the reservoir is controlled by the water temperature of the river compared to the vertical-thermal structure of the reservoir in late spring and early summer. The measurements reported here document the longitudinal and vertical pattern of temperature, specific conductance, and oxygen concentration on several dates in 1992, 1994, and 1995.

  12. Ion microscopy with resonant ionization mass spectrometry : time-of-flight depth profiling with improved isotopic precision.

    SciTech Connect

    Pellin, M. J.; Veryovkin, I. V.; Levine, J.; Zinovev, A.; Davis, A. M.; Stephan, T.; Tripa, C. E.; King, B. V.; Savina, M. R.

    2010-01-01

    There are four generally mutually exclusive requirements that plague many mass spectrometric measurements of trace constituents: (1) the small size (limited by the depth probed) of many interesting materials requires high useful yields to simply detect some trace elements, (2) the low concentrations of interesting elements require efficient discrimination from isobaric interferences, (3) it is often necessary to measure the depth distribution of elements with high surface and low bulk contributions, and (4) many applications require precise isotopic analysis. Resonant ionization mass spectrometry has made dramatic progress in addressing these difficulties over the past five years.

  13. Variations in the depth distribution of phosphorus in soil profiles and implications for model-based catchment-scale predictions of phosphorus delivery to surface waters

    NASA Astrophysics Data System (ADS)

    Owens, P. N.; Deeks, L. K.; Wood, G. A.; Betson, M. J.; Lord, E. I.; Davison, P. S.

    2008-02-01

    SummaryThe PSYCHIC process-based model for predicting sediment and phosphorus (P) transfer within catchments uses spatial data on soil-P derived from the National Soil Inventory (NSI) data set. These soil-P values are based on bulked 0-15 cm depth and do not account for variations in soil-P with depth. We describe the depth distribution of soil-P (total and Olsen) in grassland and arable soils for the dominant soil types in the two PSYCHIC study catchments: the Avon and the Wye, UK. There were clear variations in soil-P (particularly Olsen-P) concentrations with depth in untilled grassland soils while concentrations of total-P were broadly constant within the plough layer of arable soils. Concentrations of Olsen-P in arable soils, however, exhibited maximum values near the soil surface reflecting surface applications of fertilisers and manures between consecutive ploughing events. When the soil-P concentrations for the surface soil (0-5 cm average) were compared to both the profile-averaged (0-15 cm) and the NSI (0-15 cm) values, those for the surface soil were considerably greater than those for the average 0-15 cm depth. Modelled estimates of P loss using the depth-weighted average soil-P concentrations for the 0-5 cm depth layer were up to 14% greater than those based on the NSI data set due to the preferential accumulation of P at the soil surface. These findings have important implications for the use of soil-P data (and other data) in models to predict P losses from land to water and the interpretation of these predictions for river basin management.

  14. Feasibility of tropospheric water vapor profiling using infrared heterodyne differential absorption lidar

    SciTech Connect

    Grund, C.J.; Hardesty, R.M.; Rye, B.J.

    1996-04-01

    The development and verification of realistic climate model parameterizations for clouds and net radiation balance and the correction of other site sensor observations for interferences due to the presence of water vapor are critically dependent on water vapor profile measurements. In this study, we develop system performance models and examine the potential of infrared differential absoroption lidar (DIAL) to determine the concentration of water vapor.

  15. Chemical weathering of a marine terrace chronosequence, Santa Cruz, California I: Interpreting rates and controls based on soil concentration-depth profiles

    USGS Publications Warehouse

    White, A.F.; Schulz, M.S.; Vivit, D.V.; Blum, A.E.; Stonestrom, D.A.; Anderson, S.P.

    2008-01-01

    The spatial and temporal changes in element and mineral concentrations in regolith profiles in a chronosequence developed on marine terraces along coastal California are interpreted in terms of chemical weathering rates and processes. In regoliths up to 15 m deep and 226 kyrs old, quartz-normalized mass transfer coefficients indicate non-stoichiometric preferential release of Sr > Ca > Na from plagioclase along with lesser amounts of K, Rb and Ba derived from K-feldspar. Smectite weathering results in the loss of Mg and concurrent incorporation of Al and Fe into secondary kaolinite and Fe-oxides in shallow argillic horizons. Elemental losses from weathering of the Santa Cruz terraces fall within the range of those for other marine terraces along the Pacific Coast of North America. Residual amounts of plagioclase and K-feldspar decrease with terrace depth and increasing age. The gradient of the weathering profile bs is defined by the ratio of the weathering rate, R to the velocity at which the profile penetrates into the protolith. A spreadsheet calculator further refines profile geometries, demonstrating that the non-linear regions at low residual feldspar concentrations at shallow depth are dominated by exponential changes in mineral surface-to-volume ratios and at high residual feldspar concentrations, at greater depth, by the approach to thermodynamic saturation. These parameters are of secondary importance to the fluid flux qh, which in thermodynamically saturated pore water, controls the weathering velocity and mineral losses from the profiles. Long-term fluid fluxes required to reproduce the feldspar weathering profiles are in agreement with contemporary values based on solute Cl balances (qh = 0.025-0.17 m yr-1). During saturation-controlled and solute-limited weathering, the greater loss of plagioclase relative to K-feldspar is dependent on the large difference in their respective solubilities instead of the small difference between their respective

  16. Differential Absorption Lidar to Measure Sub-Hourly Variation of Tropospheric Ozone Profiles

    NASA Technical Reports Server (NTRS)

    Kuang, Shi; Burris, John F.; Newchurch, Michael J.; Johnson, Steve; Long, Stephanie

    2009-01-01

    A tropospheric ozone Differential Absorption Lidar (DIAL) system, developed jointly by the University of Alabama at Huntsville and NASA, is making regular observations of ozone vertical distributions between 1 and 8 km with two receivers under both daytime and nighttime conditions using lasers at 285 and 291 nm. This paper describes the lidar system and analysis technique with some measurement examples. An iterative aerosol correction procedure reduces the retrieval error arising from differential aerosol backscatter in the lower troposphere. Lidar observations with coincident ozonesonde flights demonstrate that the retrieval accuracy ranges from better than 10% below 4 km to better than 20% below 8 km with 750-m vertical resolution and 10-min temporal integration

  17. Differential Absorption Lidar to Measure Subhourly Variation of Tropospheric Ozone Profiles

    NASA Technical Reports Server (NTRS)

    Kuang, Shi; Burris, John F.; Newchurch, Michael J.; Johnson, Steve; Long, Stephania

    2011-01-01

    A tropospheric ozone Differential Absorption Lidar system, developed jointly by The University of Alabama in Huntsville and the National Aeronautics and Space Administration, is making regular observations of ozone vertical distributions between 1 and 8 km with two receivers under both daytime and nighttime conditions using lasers at 285 and 291 nm. This paper describes the lidar system and analysis technique with some measurement examples. An iterative aerosol correction procedure reduces the retrieval error arising from differential aerosol backscatter in the lower troposphere. Lidar observations with coincident ozonesonde flights demonstrate that the retrieval accuracy ranges from better than 10% below 4 km to better than 20% below 8 km with 750-m vertical resolution and 10-min 17 temporal integration.

  18. Into the Deep: Variability in Soil Microbial Communities and Carbon Turnover Along a Tropical Forest Soil Depth Profile

    NASA Astrophysics Data System (ADS)

    Pett-Ridge, J.; McFarlane, K. J.; Heckman, K. A.; Reed, S.; Wood, T. E.

    2015-12-01

    Tropical forest soils store more carbon (C) than any other terrestrial ecosystem and exchange vast amounts of CO2, water, and energy with the atmosphere. Much of this C is leached and stored within deeper soil layers, but we know exceedingly little about the fate of this C or the microbial communities that drive deep soil biogeochemistry. From the data that do exist, most organic matter (OM) in tropical soils appears associated with mineral particles, suggesting deep soils may provide greater C stabilization due to organo-metal co-precipitation and mineral-surface interactions. However, few studies have evaluated sub-surface soils in tropical ecosystems, the turnover times of deep soil C, and sensitivity of this C to global environmental change. To address this critical research need, we quantified C pools, microbial communities and soil radiocarbon turnover times in bulk soils and soil fractions [free light (unprotected), dense (mineral-associated)] from 0-140 cm in replicate soil pits in the Luquillo Experimental Forest, Puerto Rico. Unsurprisingly, we found soil C, nitrogen, and root and microbial biomass all declined exponentially with depth; total C stocks dropped from 5.5 % at the surface to <0.5% at 140cm depth. Soil OM 14C and mean turnover times were variable across replicate horizons, ranging from 3-1500 years at the surface (0-20 cm), to 5000-40,000 years at 140 cm depth. Soil C in the mineral associated fraction was much older than the free light fraction C, which reflected modern 14C at all depths. In comparison to temperate deciduous forests, these 14C values reflect far older soil C, and OM decomposition that highly favors free light C pools, even at depth. While previous work suggests these low C tropical subsoils contain small but metabolically active microbial communities at depths of ~100cm, these organisms appear highly OM limited, and preferentially degrade recent inputs. In the coming half century, tropical forests are predicted to see a 2 - 5

  19. Pattern and intensity of human impact on coral reefs depend on depth along the reef profile and on the descriptor adopted

    NASA Astrophysics Data System (ADS)

    Nepote, Ettore; Bianchi, Carlo Nike; Chiantore, Mariachiara; Morri, Carla; Montefalcone, Monica

    2016-09-01

    Coral reefs are threatened by multiple global and local disturbances. The Maldives, already heavily hit by the 1998 mass bleaching event, are currently affected also by growing tourism and coastal development that may add to global impacts. Most of the studies investigating effects of local disturbances on coral reefs assessed the response of communities along a horizontal distance from the impact source. This study investigated the status of a Maldivian coral reef around an island where an international touristic airport has been recently (2009-2011) built, at different depths along the reef profile (5-20 m depth) and considering the change in the percentage of cover of five different non-taxonomic descriptors assessed through underwater visual surveys: hard corals, soft corals, other invertebrates, macroalgae and abiotic attributes. Eight reefs in areas not affected by any coastal development were used as controls and showed a reduction of hard coral cover and an increase of abiotic attributes (i.e. sand, rock, coral rubble) at the impacted reef. However, hard coral cover, the most widely used descriptor of coral reef health, was not sufficient on its own to detect subtle indirect effects that occurred down the reef profile. Selecting an array of descriptors and considering different depths, where corals may find a refuge from climate impacts, could guide the efforts of minimising local human pressures on coral reefs.

  20. Predicting the profile of nutrients available for absorption: from nutrient requirement to animal response and environmental impact.

    PubMed

    Dijkstra, J; Kebreab, E; Mills, J A N; Pellikaan, W F; López, S; Bannink, A; France, J

    2007-02-01

    Current feed evaluation systems for dairy cattle aim to match nutrient requirements with nutrient intake at pre-defined production levels. These systems were not developed to address, and are not suitable to predict, the responses to dietary changes in terms of production level and product composition, excretion of nutrients to the environment, and nutrition related disorders. The change from a requirement to a response system to meet the needs of various stakeholders requires prediction of the profile of absorbed nutrients and its subsequent utilisation for various purposes. This contribution examines the challenges to predicting the profile of nutrients available for absorption in dairy cattle and provides guidelines for further improved prediction with regard to animal production responses and environmental pollution.The profile of nutrients available for absorption comprises volatile fatty acids, long-chain fatty acids, amino acids and glucose. Thus the importance of processes in the reticulo-rumen is obvious. Much research into rumen fermentation is aimed at determination of substrate degradation rates. Quantitative knowledge on rates of passage of nutrients out of the rumen is rather limited compared with that on degradation rates, and thus should be an important theme in future research. Current systems largely ignore microbial metabolic variation, and extant mechanistic models of rumen fermentation give only limited attention to explicit representation of microbial metabolic activity. Recent molecular techniques indicate that knowledge on the presence and activity of various microbial species is far from complete. Such techniques may give a wealth of information, but to include such findings in systems predicting the nutrient profile requires close collaboration between molecular scientists and mathematical modellers on interpreting and evaluating quantitative data. Protozoal metabolism is of particular interest here given the paucity of quantitative data

  1. Application of slope-polishing technique for depth profile of selenized CIGS by micro-Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Kwon, Min-Su; Kang, Jeong-yoon; Kim, SeongYeon; Kim, JunHo; Jeon, Chan-Wook

    2016-08-01

    Micro-Raman analysis was carried out on two Cu(In,Ga)Se2 films to determine the location of the secondary phases, which were suspected of being formed during the selenization process of Cu-In-Ga metallic precursor films. A slope polishing technique using a dimple grinder was applied to physically expand the film thickness by several hundred fold, which allowed high resolution Raman analysis. Various secondary phases including CuxSe, InSe, Se, and MoySe at different depths were identified without need for time-consuming sputter etching, which may adversely affect the film chemistry. With the help of the new sample preparation method for depth analysis of thin film, a precise decision on the location of those secondary phases along the film thickness and better understanding of the reaction mechanism was enabled.

  2. Time-resolved OCT-μPIV: a new microscopic PIV technique for noninvasive depth-resolved pulsatile flow profile acquisition

    NASA Astrophysics Data System (ADS)

    Chen, Chia-Yuan; Menon, Prahlad G.; Kowalski, William; Pekkan, Kerem

    2013-01-01

    In vivo acquisition of endothelial wall shear stress requires instantaneous depth-resolved whole-field pulsatile flow profile measurements in microcirculation. High-accuracy, quantitative and non- invasive velocimetry techniques are essential for emerging real-time mechano-genomic investigations. To address these research needs, a novel biological flow quantification technique, OCT-μPIV, was developed utilizing high-speed optical coherence tomography (OCT) integrated with microscopic Particle Image Velocimetry (μPIV). This technique offers the unique advantage of simultaneously acquiring blood flow profiles and vessel anatomy along arbitrarily oriented sagittal planes. The process is instantaneous and enables real-time 3D flow reconstruction without the need for computationally intensive image processing compared to state-of-the-art velocimetry techniques. To evaluate the line-scanning direction and speed, four sets of parametric synthetic OCT-μPIV data were generated using an in-house code. Based on this investigation, an in vitro experiment was designed at the fastest scan speed while preserving the region of interest providing the depth-resolved velocity profiles spanning across the width of a micro-fabricated channel. High-agreement with the analytical flow profiles was achieved for different flow rates and seed particle types and sizes. Finally, by employing blood cells as non-invasive seeding particles, in vivo embryonic vascular velocity profiles in multiple vessels were measured in the early chick embryo. The pulsatile flow frequency and peak velocity measurements were also acquired with OCT-μPIV, which agreed well with previous reported values. These results demonstrate the potential utility of this technique to conduct practical microfluidic and non-invasive in vivo studies for embryonic blood flows.

  3. Time-resolved OCT-μPIV: a new microscopic PIV technique for noninvasive depth-resolved pulsatile flow profile acquisition

    NASA Astrophysics Data System (ADS)

    Chen, Chia-Yuan; Menon, Prahlad G.; Kowalski, William; Pekkan, Kerem

    2012-12-01

    In vivo acquisition of endothelial wall shear stress requires instantaneous depth-resolved whole-field pulsatile flow profile measurements in microcirculation. High-accuracy, quantitative and non- invasive velocimetry techniques are essential for emerging real-time mechano-genomic investigations. To address these research needs, a novel biological flow quantification technique, OCT-μPIV, was developed utilizing high-speed optical coherence tomography (OCT) integrated with microscopic Particle Image Velocimetry (μPIV). This technique offers the unique advantage of simultaneously acquiring blood flow profiles and vessel anatomy along arbitrarily oriented sagittal planes. The process is instantaneous and enables real-time 3D flow reconstruction without the need for computationally intensive image processing compared to state-of-the-art velocimetry techniques. To evaluate the line-scanning direction and speed, four sets of parametric synthetic OCT-μPIV data were generated using an in-house code. Based on this investigation, an in vitro experiment was designed at the fastest scan speed while preserving the region of interest providing the depth-resolved velocity profiles spanning across the width of a micro-fabricated channel. High-agreement with the analytical flow profiles was achieved for different flow rates and seed particle types and sizes. Finally, by employing blood cells as non-invasive seeding particles, in vivo embryonic vascular velocity profiles in multiple vessels were measured in the early chick embryo. The pulsatile flow frequency and peak velocity measurements were also acquired with OCT-μPIV, which agreed well with previous reported values. These results demonstrate the potential utility of this technique to conduct practical microfluidic and non-invasive in vivo studies for embryonic blood flows.

  4. Measurement of axial neutral density profiles in a microwave discharge ion thruster by laser absorption spectroscopy with optical fiber probes

    SciTech Connect

    Tsukizaki, Ryudo; Koizumi, Hiroyuki; Nishiyama, Kazutaka; Kuninaka, Hitoshi

    2011-12-15

    In order to reveal the physical processes taking place within the ''{mu}10'' microwave discharge ion thruster, internal plasma diagnosis is indispensable. However, the ability of metallic probes to access microwave plasmas biased at a high voltage is limited from the standpoints of the disturbance created in the electric field and electrical isolation. In this study, the axial density profiles of excited neutral xenon were successfully measured under ion beam acceleration by using a novel laser absorption spectroscopy system. The target of the measurement was metastable Xe I 5p{sup 5}({sup 2}P{sup 0}{sub 3/2})6s[{sup 3}/{sub 2}]{sup 0}{sub 2} which absorbed a wavelength of 823.16 nm. Signals from laser absorption spectroscopy that swept a single-mode optical fiber probe along the line of sight were differentiated and converted into axial number densities of the metastable neutral particles in the plasma source. These measurements revealed a 10{sup 18} m{sup -3} order of metastable neutral particles situated in the waveguide, which caused two different modes during the operation of the {mu}10 thruster. This paper reports a novel spectroscopic measurement system with axial resolution for microwave plasma sources utilizing optical fiber probes.

  5. Measurement of axial neutral density profiles in a microwave discharge ion thruster by laser absorption spectroscopy with optical fiber probes.

    PubMed

    Tsukizaki, Ryudo; Koizumi, Hiroyuki; Nishiyama, Kazutaka; Kuninaka, Hitoshi

    2011-12-01

    In order to reveal the physical processes taking place within the "μ10" microwave discharge ion thruster, internal plasma diagnosis is indispensable. However, the ability of metallic probes to access microwave plasmas biased at a high voltage is limited from the standpoints of the disturbance created in the electric field and electrical isolation. In this study, the axial density profiles of excited neutral xenon were successfully measured under ion beam acceleration by using a novel laser absorption spectroscopy system. The target of the measurement was metastable Xe I 5p(5)((2)P(0) (3/2))6s[3/2](0) (2) which absorbed a wavelength of 823.16 nm. Signals from laser absorption spectroscopy that swept a single-mode optical fiber probe along the line of sight were differentiated and converted into axial number densities of the metastable neutral particles in the plasma source. These measurements revealed a 10(18) m(-3) order of metastable neutral particles situated in the waveguide, which caused two different modes during the operation of the μ10 thruster. This paper reports a novel spectroscopic measurement system with axial resolution for microwave plasma sources utilizing optical fiber probes. PMID:22225195

  6. Hydrodynamical simulations of the jet in the symbiotic star MWC 560. I. Structure, emission and synthetic absorption line profiles

    NASA Astrophysics Data System (ADS)

    Stute, M.; Camenzind, M.; Schmid, H. M.

    2005-01-01

    We performed hydrodynamical simulations with and without radiative cooling of jet models with parameters representative of the symbiotic system MWC 560. For symbiotic systems we have to perform jet simulations of a pulsed underdense jet in a high density ambient medium. We present the jet structure resulting from our simulations and calculate emission plots which account for expected radiative processes. In addition, our calculations provide expansion velocities for the jet bow shock, the density and temperature structure in the jet, and the propagation and evolution of the jet pulses. In MWC 560 the jet axis is parallel to the line of sight so that the outflowing jet gas can be seen as blue shifted, variable absorption lines in the continuum of the underlying jet source. Based on our simulations we calculate and discuss synthetic absorption profiles. Based on a detailed comparison between model spectra and observations we discuss our hydrodynamical calculations for a pulsed jet in MWC 560 and suggest improvements for future models. Figures \\ref{skizze}, \\ref{modi_det}, \\ref{slice_cool_p}, \\ref{NV_3.0_synch}, \\ref{modelicool_greyscale}, \\ref{line_rem}-\\ref{line_dv} and \\ref{line_zmax} are only available in electronic form at http://www.edpsciences.org

  7. ASYMMETRIC ABSORPTION PROFILES OF Ly{alpha} AND Ly{beta} IN DAMPED Ly{alpha} SYSTEMS

    SciTech Connect

    Lee, Hee-Won

    2013-08-01

    Damped Ly{alpha} systems observed in the quasar spectra are characterized by a high neutral hydrogen column density, N{sub HI} > 2 x 10{sup 20} cm{sup -2}. The absorption wing profiles are often fitted using the Voigt function due to the fact that the scattering cross section near the resonant line center is approximately described by the Lorentzian function. Since a hydrogen atom has infinitely many p states that participate in the electric dipole interaction, the cross section starts to deviate from the Lorentzian in an asymmetric way in the line wing regions. We investigate this asymmetry in the absorption line profiles around Ly{alpha} and Ly{beta} as a function of the neutral hydrogen column density N{sub HI}. In terms of {Delta}{lambda} {identical_to} {lambda} - {lambda}{sub {alpha}}, we expand the Kramers-Heisenberg formula around Ly{alpha} to find {sigma}({lambda}) {approx_equal} (0.5f{sub 12}){sup 2}{sigma}{sub T}({Delta}{lambda}/{lambda}{sub {alpha}}){sup -2}[1 + 3.792({Delta}{lambda}/{lambda}{sub {alpha}})], where f{sub 12} and {sigma}{sub T} are the oscillator strength of Ly{alpha} and the Thomson scattering cross section, respectively. In terms of {Delta}{lambda}{sub 2} {identical_to} {lambda} - {lambda}{sub {beta}} in the vicinity of Ly{beta}, the total scattering cross section, given as the sum of cross sections for Rayleigh and Raman scattering, is shown to be {sigma}({lambda}) {approx_equal} {sigma}{sub T}(0.5f{sub 13}){sup 2}(1 + R{sub 0})({Delta}{lambda}{sub 2}/{lambda}{sub {beta}}){sup -2}[1 - 24.68({Delta}{lambda}{sub 2}/{lambda}{sub {beta}})] with f{sub 13} and the factor R{sub 0} = 0.1342 being the oscillator strength for Ly{beta} and the ratio of the Raman cross section to Rayleigh cross section, respectively. A redward asymmetry develops around Ly{alpha}, whereas a blue asymmetry is obtained for Ly{beta}. The absorption center shifts are found to be almost proportional to the neutral hydrogen column density.

  8. Penetration depth and absorption mechanisms of spin currents in Ir{sub 20}Mn{sub 80} and Fe{sub 50}Mn{sub 50} polycrystalline films by ferromagnetic resonance and spin pumping

    SciTech Connect

    Merodio, P.; Ghosh, A.; Lemonias, C.; Gautier, E.; Ebels, U.; Chshiev, M.; Béa, H. E-mail: helene.bea@cea.fr; Baltz, V. E-mail: helene.bea@cea.fr

    2014-01-20

    Spintronics relies on the spin dependent transport properties of ferromagnets (Fs). Although antiferromagnets (AFs) are used for their magnetic properties only, some fundamental F-spintronics phenomena like spin transfer torque, domain wall motion, and tunnel anisotropic magnetoresistance also occur with AFs, thus making AF-spintronics attractive. Here, room temperature critical depths and absorption mechanisms of spin currents in Ir{sub 20}Mn{sub 80} and Fe{sub 50}Mn{sub 50} are determined by F-resonance and spin pumping. In particular, we find room temperature critical depths originating from different absorption mechanisms: dephasing for Ir{sub 20}Mn{sub 80} and spin flipping for Fe{sub 50}Mn{sub 50}.

  9. Combined evaluation of grazing incidence X-ray fluorescence and X-ray reflectivity data for improved profiling of ultra-shallow depth distributions.

    PubMed

    Ingerle, D; Meirer, F; Pepponi, G; Demenev, E; Giubertoni, D; Wobrauschek, P; Streli, C

    2014-09-01

    The continuous downscaling of the process size for semiconductor devices pushes the junction depths and consequentially the implantation depths to the top few nanometers of the Si substrate. This motivates the need for sensitive methods capable of analyzing dopant distribution, total dose and possible impurities. X-ray techniques utilizing the external reflection of X-rays are very surface sensitive, hence providing a non-destructive tool for process analysis and control. X-ray reflectometry (XRR) is an established technique for the characterization of single- and multi-layered thin film structures with layer thicknesses in the nanometer range. XRR spectra are acquired by varying the incident angle in the grazing incidence regime while measuring the specular reflected X-ray beam. The shape of the resulting angle-dependent curve is correlated to changes of the electron density in the sample, but does not provide direct information on the presence or distribution of chemical elements in the sample. Grazing Incidence XRF (GIXRF) measures the X-ray fluorescence induced by an X-ray beam incident under grazing angles. The resulting angle dependent intensity curves are correlated to the depth distribution and mass density of the elements in the sample. GIXRF provides information on contaminations, total implanted dose and to some extent on the depth of the dopant distribution, but is ambiguous with regard to the exact distribution function. Both techniques use similar measurement procedures and data evaluation strategies, i.e. optimization of a sample model by fitting measured and calculated angle curves. Moreover, the applied sample models can be derived from the same physical properties, like atomic scattering/form factors and elemental concentrations; a simultaneous analysis is therefore a straightforward approach. This combined analysis in turn reduces the uncertainties of the individual techniques, allowing a determination of dose and depth profile of the implanted

  10. Combined evaluation of grazing incidence X-ray fluorescence and X-ray reflectivity data for improved profiling of ultra-shallow depth distributions

    NASA Astrophysics Data System (ADS)

    Ingerle, D.; Meirer, F.; Pepponi, G.; Demenev, E.; Giubertoni, D.; Wobrauschek, P.; Streli, C.

    2014-09-01

    The continuous downscaling of the process size for semiconductor devices pushes the junction depths and consequentially the implantation depths to the top few nanometers of the Si substrate. This motivates the need for sensitive methods capable of analyzing dopant distribution, total dose and possible impurities. X-ray techniques utilizing the external reflection of X-rays are very surface sensitive, hence providing a non-destructive tool for process analysis and control. X-ray reflectometry (XRR) is an established technique for the characterization of single- and multi-layered thin film structures with layer thicknesses in the nanometer range. XRR spectra are acquired by varying the incident angle in the grazing incidence regime while measuring the specular reflected X-ray beam. The shape of the resulting angle-dependent curve is correlated to changes of the electron density in the sample, but does not provide direct information on the presence or distribution of chemical elements in the sample. Grazing Incidence XRF (GIXRF) measures the X-ray fluorescence induced by an X-ray beam incident under grazing angles. The resulting angle dependent intensity curves are correlated to the depth distribution and mass density of the elements in the sample. GIXRF provides information on contaminations, total implanted dose and to some extent on the depth of the dopant distribution, but is ambiguous with regard to the exact distribution function. Both techniques use similar measurement procedures and data evaluation strategies, i.e. optimization of a sample model by fitting measured and calculated angle curves. Moreover, the applied sample models can be derived from the same physical properties, like atomic scattering/form factors and elemental concentrations; a simultaneous analysis is therefore a straightforward approach. This combined analysis in turn reduces the uncertainties of the individual techniques, allowing a determination of dose and depth profile of the implanted

  11. Numerical analysis of dysplasia-associated changes in depth-dependent light scattering profile of cervical epithelium

    NASA Astrophysics Data System (ADS)

    Arifler, Dizem; MacAulay, Calum; Follen, Michele; Guillaud, Martial

    2013-06-01

    Dysplastic progression is known to be associated with changes in morphology and internal structure of cells. A detailed assessment of the influence of these changes on cellular scattering response is needed to develop and optimize optical diagnostic techniques. In this study, we first analyzed a set of quantitative histopathologic images from cervical biopsies and we obtained detailed information on morphometric and photometric features of segmented epithelial cell nuclei. Morphometric parameters included average size and eccentricity of the best-fit ellipse. Photometric parameters included optical density measures that can be related to dielectric properties and texture characteristics of the nuclei. These features enabled us to construct realistic three-dimensional computational models of basal, parabasal, intermediate, and superficial cell nuclei that were representative of four diagnostic categories, namely normal (or negative for dysplasia), mild dysplasia, moderate dysplasia, and severe dysplasia or carcinoma in situ. We then employed the finite-difference time-domain method, a popular numerical tool in electromagnetics, to compute the angle-resolved light scattering properties of these representative models. Results indicated that a high degree of variability can characterize a given diagnostic category, but scattering from moderately and severely dysplastic or cancerous nuclei was generally observed to be stronger compared to scattering from normal and mildly dysplastic nuclei. Simulation results also pointed to significant intensity level variations among different epithelial depths. This suggests that intensity changes associated with dysplastic progression need to be analyzed in a depth-dependent manner.

  12. Compositional depth profile of a native oxide LPCVD MNOS structure using X-ray photoelectron spectroscopy and chemical etching

    NASA Technical Reports Server (NTRS)

    Wurzbach, J. A.; Grunthaner, F. J.

    1983-01-01

    It is pointed out that there is no report of an unambiguous analysis of the composition and interfacial structure of MNOS (metal-nitride oxide semiconductor) systems, despite the technological importance of these systems. The present investigation is concerned with a study of an MNOS structure on the basis of a technique involving the use of X-ray photoelectron spectroscopy (XPS) with a controlled stopped-flow chemical-etching procedure. XPS is sensitive to the structure of surface layers, while stopped-flow etching permits the controlled removal of overlying material on a scale of atomic layers, to expose new surface layers as a function of thickness. Therefore, with careful analysis of observed intensities at measured depths, this combination of techniques provides depth resolution between 5 and 10 A. According to the obtained data there is intact SiO2 at the substrate interface. There appears to be a thin layer containing excess bonds to silicon on top of the SiO2.

  13. Measurements of the Depth of Maximum of Air-Shower Profiles at the Pierre Auger Observatory and their Composition Implications

    NASA Astrophysics Data System (ADS)

    de Souza, V.

    We describe how the analysis of air showers detected by the Pierre Auger Observatory leads to an accurate determination of the depth of maximum (Xmax). First, the analysis of the air-shower which leads to the reconstruction of Xmax is discussed. The properties of the detector and its measurement biases are treated and carefully taken into consideration. The Xmax results are interpreted in terms of composition, where the interpretation depends mainly on the hadronic interaction models. A global fit of the Xmax distribution yields an estimate of the abundance of four primaries species. The analysis represents the most statistically significant composition information ever obtained for energies above 1017.8 eV. The scenario that emerges shows no support for a strong flux of iron nuclei and a strong energy dependence of the proton fraction.

  14. The depth distribution of sup 90 Sr, sup 137 Cs, and sup 239,240 Pu in soil profile samples

    SciTech Connect

    Price, K.R.

    1989-04-01

    A special study was conducted at the Hanford Site and vicinity to investigate the depth distribution of {sup 90}Sr, {sup 137}Cs, and {sup 239,240}Pu in soil at two locations. Duplicate sets of samples were collected at each location from the soil surface to a depth of 30 cm in increments of 2.5 cm. Results from an onsite location near a retired nuclear fuel reprocessing facility were compared to results from a background location upwind and distant from the Site. The study showed that, regardless of location, the top 5 cm of soil contained 51 to 74% of the {sup 90}Sr, 99% of the {sup 137}Cs, and 96% of the {sup 239,240}Pu. Soil at the background location received radionuclides only from deposition of worldwide fallout, and averaged 1.6 pCi/cm{sup 2} of {sup 90}Sr, 3.0 pCi/cm{sup 2} of {sup 137}Cs, and 0.071 pCi/cm{sup 2} of {sup 239,240}Pu. Soil at the onsite location received radionuclides from deposition of both worldwide fallout and past operations of the retired fuel reprocessing facility and contained 4 times as much {sup 90}Sr, 5 times as much {sup 137}Cs, and 44 times as much {sup 239,240}Pu as the background location. (Pacific Northwest Laboratory is operated for the US Department of Energy by Battelle Memorial Institute under Contract AC06-76RLO1830.) 8 refs., 2 figs.

  15. Depth profiling for the identification of unknown substances and concealed content at remote distances using time-resolved stand-off Raman spectroscopy.

    PubMed

    Zachhuber, Bernhard; Gasser, Christoph; Ramer, Georg; Chrysostom, Engelene t H; Lendl, Bernhard

    2012-08-01

    Time-resolved stand-off Raman spectroscopy was used to determine both the position and identity of substances relative to each other at remote distances (up to tens of meters). Spectral information of three xylene isomers, toluene, and sodium chlorate was obtained at a distance of 12 m from the setup. Pairs and triplets of these samples were placed at varying distances (10-60 cm) relative to each other. Via the photon time of flight the distance between the individual samples was determined to an accuracy of 7% (corresponding to a few cm) of the physically measured distance. Furthermore, at a distance of 40 m, time-resolved Raman depth profiling was used to detect sodium chlorate in a white plastic container that was non-transparent to the human eye. The combination of the ranging capabilities of Raman LIDAR (sample location usually determined using prior knowledge of the analyte of interest) with stand-off Raman spectroscopy (analyte detection at remote distances) provides the capability for depth profile identification of unknown substances and analysis of concealed content in distant objects. To achieve these results, a 532 nm laser with a pulse length of 4.4 ns was synchronized to an intensified charge-coupled device camera with a minimum gate width of 500 ps. For automated data analysis a multivariate curve resolution algorithm was employed. PMID:22800681

  16. A one-dimensional Fickian model to predict the Ga depth profiles in three-stage Cu(In,Ga)Se{sub 2}

    SciTech Connect

    Rodriguez-Alvarez, H.; Mainz, R.; Sadewasser, S.

    2014-05-28

    We present a one-dimensional Fickian model that predicts the formation of a double Ga gradient during the fabrication of Cu(In,Ga)Se{sub 2} thin films by three-stage thermal co-evaporation. The model is based on chemical reaction equations, structural data, and effective Ga diffusivities. In the model, the Cu(In,Ga)Se{sub 2} surface is depleted from Ga during the deposition of Cu-Se in the second deposition stage, leading to an accumulation of Ga near the back contact. During the third deposition stage, where In-Ga-Se is deposited at the surface, the atomic fluxes within the growing layer are inverted. This results in the formation of a double Ga gradient within the Cu(In,Ga)Se{sub 2} layer and reproduces experimentally observed Ga distributions. The final shape of the Ga depth profile strongly depends on the temperatures, times and deposition rates used. The model is used to evaluate possible paths to flatten the marked Ga depth profile that is obtained when depositing at low substrate temperatures. We conclude that inserting Ga during the second deposition stage is an effective way to achieve this.

  17. Concentration and relaxation depth profiles of InxGa1-xAs/GaAs and GaAs1-xPx/GaAs graded epitaxial films studied by x-ray diffraction

    NASA Astrophysics Data System (ADS)

    Benediktovitch, A.; Ulyanenkov, A.; Rinaldi, F.; Saito, K.; Kaganer, V. M.

    2011-07-01

    A method is proposed to determine the concentration and relaxation depth profiles in graded epitaxial films from x-ray reciprocal space maps (RSMs). Various approximations in the kinematical x-ray diffraction from epitaxial films with the misfit dislocation density depth profile are developed. We show that a symmetric and an asymmetric RSM, or two asymmetric RSMs, contain enough information to obtain the concentration, relaxation, and lattice tilt depth profiles without any additional assumptions. The proposed approach is applied to InxGa1-xAs/GaAs and GaAs1-xPx/GaAs epitaxial graded films. The reconstructed concentration and dislocation density depth profiles are found to be in an agreement with the ones expected from the growth conditions.

  18. Depth profiles of spectral and hydrological characteristics of water and their relation to abundances of green sulfur bacteria in the stratified lakes of the White Sea

    NASA Astrophysics Data System (ADS)

    Kharcheva, Anastasia V.; Krasnova, Elena D.; Gorlenko, Vladimir M.; Lunina, Olga N.; Savvichev, Alexander S.; Voronov, Dmitry A.; Zhiltsova, Anna A.; Patsaeva, Svetlana V.

    2016-04-01

    We analyze the results received from two expeditions performed in August-September 2013, August-September 2014 and February 2015 in the Kandalaksha Bay of the White Sea. Depth profiles of hydrological characteristics and optical properties of water were recorded for five marine lakes being on different stages of isolation from the White Sea. Those relic lakes demonstrate a tendency to meromixis and are characterized by apparent stratification of the water bodies from the brackish top layer to the bottom salt water. Maximal concentrations of anoxygenic phototrophs (green sulfur bacteria) were found at depths close to the redox interface in all the studied lakes. To discriminate differently pigmented groups of microorganisms the fluorescence emission spectra of bacteriochlorophylls from the living cells were used. We puzzle out the data on light spectrum propagation through the water body in each lake using optical properties of water (attenuation spectra) in the UV, visible and NIR ranges, as well as direct measurements of the total irradiances at various depths. The changes in optical characteristics of water in the stratified reservoirs due to cromophoric dissolved organic matter (CDOM) and microbial pigments affect the light intensity and its spectral distribution at each water layer thus influencing the living conditions for differently pigmented phototrophic microorganisms and determining the composition of microbial community.

  19. ERD measurement of depth profiles of H and Li in Pt-coated LiCoO2 thin films

    NASA Astrophysics Data System (ADS)

    Tsuchiya, B.; Morita, K.; Iriyama, Y.; Majima, T.; Tsuchida, H.

    2013-11-01

    By combining elastic recoil detection (ERD) analysis with Rutherford backscattering spectrometry (RBS) using 9.0-MeV oxygen-ion (O4+) probe beams from a tandem accelerator, we simultaneously investigated the distributions of lithium (Li), hydrogen (H), cobalt (Co), and platinum (Pt) in 20 nm Pt/260 nm LiCoO2 multi-layer thin films acting as the positive electrode in a solid-state Li+ ion battery and, deposited on Li1.4Ti2Si0.4P2.6O12-AlPO4 (LATP) substrates by using pulsed laser deposition. Measurement of the ERD and RBS spectra revealed the effects of Pt deposition on the hydrogen absorption characteristics of the LiCoO2 thin films, with segregation of Co to the surface as a catalyst. We speculate from the results that the presence of H in the LiCoO2 thin films has a marked influence on Li+ ion conduction in Li-battery systems.

  20. Measurement of the absorption line profiles of water vapour isotopomers at 1.39 {mu}m using the methods of diode laser spectroscopy

    SciTech Connect

    Kuz'michev, A S; Nadezhdinskii, Aleksandr I; Ponurovskii, Ya Ya

    2011-07-31

    The issues related to high-precision measurement of the absorption line profiles of water vapour and its isotopomers using the methods of diode laser spectroscopy in the near IR range aimed at the analysis and detection of greenhouse gases are considered. The absorption line shape of H{sub 2}{sup 16}O is investigated as a function of pressure of different buffer gases. The influence of the instrument function of the diode laser (DL) on the precision of measuring the line profile is studied. From fitting the profile of Doppler-broadened H{sub 2}{sup 16}O absorption line to a model profile the lasing line width of the DL with a fibre pigtail is determined. The frequencies and intensities of absorption lines of water isotopomers H{sub 2}{sup 16}O, H{sub 2}{sup 17}O, H{sub 2}{sup 18}O, and HDO are measured in the range of DL oscillation. Analytical spectral regions are chosen for distant probing of water vapour using an airborne lab. (laser spectroscopy)

  1. In-depth 2-DE reference map of Aspergillus fumigatus and its proteomic profiling on exposure to itraconazole.

    PubMed

    Gautam, Poonam; Mushahary, Dolly; Hassan, Wazid; Upadhyay, Santosh Kumar; Madan, Taruna; Sirdeshmukh, Ravi; Sundaram, Curam Sreenivasacharlu; Sarma, Puranam Usha

    2016-07-01

    Aspergillus fumigatus (A. fumigatus) is a medically important opportunistic fungus that may lead to invasive aspergillosis in humans with weak immune system. Proteomic profiling of this fungus on exposure to itraconazole (ITC), an azole antifungal drug, may lead to identification of its molecular targets and better understanding on the development of drug resistance against ITC in A. fumigatus. Here, proteome analysis was performed using 2-DE followed by mass spectrometric analysis which resulted in identification of a total of 259 unique proteins. Further, proteome profiling of A. fumigatus was carried out on exposure to ITC, 0.154 μg/ml, the minimum inhibitory concentration (MIC50). Image analysis showed altered levels of 175 proteins (66 upregulated and 109 downregulated) of A. fumigatus treated with ITC as compared to the untreated control. Peptide mass fingerprinting led to the identification of 54 proteins (12 up-regulated and 42 down-regulated). The differentially expressed proteins include proteins related to cell stress, carbohydrate metabolism and amino acid metabolism. We also observed four proteins, including nucleotide phosphate kinase (NDK), that are reported to interact with calcineurin, a protein involved in regulation of cell morphology and fungal virulence. Comparison of differentially expressed proteins on exposure to ITC with artemisinin (ART), an antimalarial drug with antifungal activity(1), revealed a total of 26 proteins to be common among them suggesting that common proteins and pathways are targeted by these two antifungal agents. The proteins targeted by ITC may serve as important leads for development of new antifungal drugs. PMID:26868900

  2. Subtropical denudation rates of granitic regolith along a hill ridge in Longnan, SE China derived from cosmogenic nuclide depth-profiles

    NASA Astrophysics Data System (ADS)

    Cui, Li-Feng; Liu, Cong-Qiang; Xu, Sheng; Zhao, Zhi-Qi; Liu, Tao-Ze; Liu, Wen-Jing; Zhang, Zhuo-Jun

    2016-03-01

    The denudation rates of granitic regolith are essential to our understanding of the geomorphic changes and landscape evolution of a region and for soil resource management. We present denudation rates derived from four regolith profiles along a granitic slope in Longnan, southeastern China, using depth profiles of in-situ produced cosmogenic 10Be and 26Al. The concentration ranges of 10Be, 26Al, and 26Al/10Be ratio were 2.98 × 104-1.72 × 105 atoms/g, 2.18 × 105-1.12 × 106 atoms/g, and 6.07-7.50, respectively. Analysis of the results shows that the surface-lowering rates are 19 ± 3, 41 ± 4, 47 ± 4, 22 ± 3 m/Ma for the four profiles from the foot of the hill to the top along the hillslope. The mean denudation rate for the four profiles is ∼30 m/Ma. This rate is lower than that derived by other methods in nearby areas and also lower than the mean global denudation rate in basins deduced from 10Be levels in river sediment; this suggests an unevenness of the erosion process on a basin scale. The denudation rate at the ridge is twice that estimated for the summit and the foothill, indicating that the hillslope has not reached its steady state. Thus, the slopes below the ridge may become smoother and the ridge sharper in the long-term landscape evolution. The difference in topography may account for the variance among the profiles. In addition, bioturbation may have contributed to the lower concentration in the surface layer at the foot of the hill, producing a higher denudation rate than the average for the basin. The concentration of insoluble element Zr in the soil surface layer and fresh bedrock suggests that chemical weathering accounts for about one third of the denudation rate.

  3. Integrated approach using multistep enzyme digestion, TiO2 enrichment, and database search for in-depth phosphoproteomic profiling.

    PubMed

    Han, Dohyun; Jin, Jonghwa; Yu, Jiyoung; Kim, Kyunggon; Kim, Youngsoo

    2015-01-01

    Protein phosphorylation is a major PTM that regulates important cell signaling mechanisms. In-depth phosphoproteomic analysis provides a method of examining this complex interplay, yielding a mechanistic understanding of the cellular processes and pathogenesis of various diseases. However, the analysis of protein phosphorylation is challenging, due to the low concentration of phosphoproteins in highly complex mixtures and the high variability of phosphorylation sites. Thus, typical phosphoproteome studies that are based on MS require large amounts of starting material and extensive fractionation steps to reduce the sample complexity. To this end, we present a simple strategy (integrated multistep enzyme digestion, enrichment, database search-iMEED) to improve coverage of the phosphoproteome from lower sample amounts which is faster than other commonly used approaches. It is inexpensive and adaptable to low sample amounts and saves time and effort with regard to sample preparation and mass spectrometric analysis, allowing samples to be prepared without prefractionation or specific instruments, such as HPLC. All MS data have been deposited in the ProteomeXchange with identifier PXD001033 (http://proteomecentral.proteomexchange.org/dataset/PXD001033). PMID:25159016

  4. Improved stratigraphic dating at a low accumulation Alpine ice core through laser ablation trace element profiling at sub-mm depth resolution

    NASA Astrophysics Data System (ADS)

    Bohleber, Pascal; Spaulding, Nicole; Mayewski, Paul; Sneed, Sharon; Handley, Mike; Erhardt, Tobias; Wagenbach, Dietmar

    2015-04-01

    The small scale Colle Gnifetti glacier saddle (4450 m asl, Monte Rosa region) is the only ice core drilling site in the European Alps with a net accumulation low enough to offer multi-millennia climate records. However, a robust interpretation of such long term records (i.e. mineral dust, stable water isotopes) at the Colle Gnifetti (CG) multi core array is strongly challenged by depositional noise associated with a highly irregular annual layer stratigraphy. In combination with a relatively large vertical strain rate and rapid layer thinning, annual layer counting gets increasingly ambiguous as of approximately 100 years. In addition, this prevents clear attribution of likely volcanic horizons to historical eruption dates. To improve stratigraphic dating under such intricate conditions, we deployed laser ablation (LA) ICP-MS at sub-mm sample resolution. We present here the first LA impurity profiles from a new Colle Gnifetti ice core drilled 73 m to bedrock in 2013 at a site where the net snow accumulation is around 20 cm w.e. per year. We contrast the LA signal variability (including Ca, Fe, Na) to continuous flow analyses (CFA) records at cm-resolution (Ca, Na, melt water conductivity, micro- particle) recorded over the whole core length. Of special concern are the lower 28 m to bedrock, which have been continuously profiled in LA Ca, thus offering the direct comparison of Ca-signals between CFA and LA. By this means, we first validate at upper depths LA based annual layer identification through agreement with CFA based counting efforts before demonstrating the LA based counting still works at depths where CFA derived annual layers become spurious since embedded in strong, multi-year cycles. Finally, LA ice core profiling of our CG core has potential for not only dating improvement but also reveals benefits in resolving highly thinned basal ice sections including accounting for micro-structural features such as grain boundaries.

  5. Depth Profiling of N and C in Ion Implanted ZnO and Si Using Deuterium Induced Nuclear Reaction Analysis

    SciTech Connect

    Kennedy, John; Murmu, Peter; Markwitz, Andreas

    2008-11-03

    Nuclear Reaction Analysis (NRA) with deuteron ion beams has been used to probe for ion implanted nitrogen and carbon with high sensitivity in zinc oxide and silicon single crystals. The ion implanted N was measured using 1.4 MeV deuteron ion beams and was found to be in agreement with calculated values. The limit of detection for N in ZnO is 8x10{sup 14} ions cm{sup -2}. Raman measurements of the ion implanted samples showed three additional modes at 275, 504, and 644 cm{sup -1} compared to the un-implanted ZnO crystals. The NRA and Raman results provided information on the N concentration, depth distribution, and structural changes that occur in dependence on the nitrogen ion fluences. The deuterium induced {sup 12}C(d,p){sup 13}C reaction was used to measure the carbon impurity/dose in ion implanted silicon. It was found that the use of a large cold shield (liquid nitrogen trap) in the ion implanter chamber greatly reduces the amount of carbon impurity on the surface of ion implanted silicon. Various implantations with N{sub 2}, O{sub 2}, NO, NO{sub 2} and Pb ions were performed with and without cooling of the liquid nitrogen trap. Simultaneous detection of ppm-level concentrations of {sup 12}C, {sup 16}O and {sup 14}N enables highly sensitive measurement of impurities that may be incorporated during the fabrication process, transport of the samples and/or storage of the samples in air.

  6. Non-invasive depth profile imaging of the stratum corneum using confocal Raman microscopy: first insights into the method.

    PubMed

    Ashtikar, Mukul; Matthäus, Christian; Schmitt, Michael; Krafft, Christoph; Fahr, Alfred; Popp, Jürgen

    2013-12-18

    The stratum corneum is a strong barrier that must be overcome to achieve successful transdermal delivery of a pharmaceutical agent. Many strategies have been developed to enhance the permeation through this barrier. Traditionally, drug penetration through the stratum corneum is evaluated by employing tape-stripping protocols and measuring the content of the analyte. Although effective, this method cannot provide a detailed information regarding the penetration pathways. To address this issue various microscopic techniques have been employed. Raman microscopy offers the advantage of label free imaging and provides spectral information regarding the chemical integrity of the drug as well as the tissue. In this paper we present a relatively simple method to obtain XZ-Raman profiles of human stratum corneum using confocal Raman microscopy on intact full thickness skin biopsies. The spectral datasets were analysed using a spectral unmixing algorithm. The spectral information obtained, highlights the different components of the tissue and the presence of drug. We present Raman images of untreated skin and diffusion patterns for deuterated water and beta-carotene after Franz-cell diffusion experiment. PMID:23764946

  7. Ground-based differential absorption lidar for water-vapor profiling: assessment of accuracy, resolution, and meteorological applications.

    PubMed

    Wulfmeyer, V; Bösenberg, J

    1998-06-20

    The accuracy and the resolution of water-vapor measurements by use of the ground-based differential absorption lidar (DIAL) system of the Max-Planck-Institute (MPI) are determined. A theoretical analysis, intercomparisons with radiosondes, and measurements in high-altitude clouds allow the conclusion that, with the MPI DIAL system, water-vapor measurements with a systematic error of <5% in the whole troposphere can be performed. Special emphasis is laid on the outstanding daytime and nighttime performance of the DIAL system in the lower troposphere. With a time resolution of 1 min the statistical error varies between 0.05 g/m(3) in the near range using 75 m and-depending on the meteorological conditions-approximately 0.25 g/m(3) at 2 km using 150-m vertical resolution. When the eddy correlation method is applied, this accuracy and resolution are sufficient to determine water-vapor flux profiles in the convective boundary layer with a statistical error of <10% in each data point to approximately 1700 m. The results have contributed to the fact that the DIAL method has finally won recognition as an excellent tool for tropospheric research, in particular for boundary layer research and as a calibration standard for radiosondes and satellites. PMID:18273352

  8. Quantitative determination of erosion rates in humid region using depth profiles of in situ-produced Be-10 and Al-26

    NASA Astrophysics Data System (ADS)

    Nakamura, A.; Yokoyama, Y.; Miyairi, Y.; Shiroya, K.; Matsuzaki, H.; Suzuki, A.

    2012-12-01

    Determination of erosion rates is important across a diverse range of disciplines in geology, geomorphology, and biogeochemistry (Granger and Riebe, 2007). Yet rates of long-term erosion have been difficult to quantify until recently. Measurements of in-situ produced terrestrial cosmogenic nuclides (TCN) allow us to understand earth surface process quantitatively (Goss and Phillips, 2001) and has been successfully used to provide erosion rates of bedrock in arid regions where negligible or small erosion process is being taken place (e.g. Cockburn et al., 1999). Environmental parameters such as mean annual precipitation have been used to explain erosion rate variability on a global scale (Bierman and Cafee, 2002). However, the relationship between erosion rates and precipitation is still under debate due in part to scarcity of data from higher mean annual precipitation regions. In addition, erosion rates deduced from drainage basins, which is the only method to quantify erosion rates in humid regions, are strongly affected by steepness of basin slope (Riebe et al., 2000). Therefore, different approach to determine the erosion rates in humid regions is required to corroborate findings from arid regions. Here we present depth profiles of in situ-produced 10Be and 26Al on hilltop sites of Japan. The contribution from unique characteristics of individual basin slope should be minimized since all sites are limited on top of the hill, allowing a direct comparison to studies of bedrock erosion rates in arid regions. The aims of this study are (1) to develop a model of TCN depth profiles, based on actually measured density in granitic saprolite, and (2) to assess climate control on erosion rates. These data indicate close linkage between earth surface process and climate. A discrepancy in the theoretical value is also observed from the depth profiles in Saga prefecture, Japan, which may support the potential of obtaining non-steady erosion process through glacial

  9. Argon Cluster Sputtering Source for ToF-SIMS Depth Profiling of Insulating Materials: High Sputter Rate and Accurate Interfacial Information.

    PubMed

    Wang, Zhaoying; Liu, Bingwen; Zhao, Evan W; Jin, Ke; Du, Yingge; Neeway, James J; Ryan, Joseph V; Hu, Dehong; Zhang, Kelvin H L; Hong, Mina; Le Guernic, Solenne; Thevuthasan, Suntharampilai; Wang, Fuyi; Zhu, Zihua

    2015-08-01

    The use of an argon cluster ion sputtering source has been demonstrated to perform superiorly relative to traditional oxygen and cesium ion sputtering sources for ToF-SIMS depth profiling of insulating materials. The superior performance has been attributed to effective alleviation of surface charging. A simulated nuclear waste glass (SON68) and layered hole-perovskite oxide thin films were selected as model systems because of their fundamental and practical significance. Our results show that high sputter rates and accurate interfacial information can be achieved simultaneously for argon cluster sputtering, whereas this is not the case for cesium and oxygen sputtering. Therefore, the implementation of an argon cluster sputtering source can significantly improve the analysis efficiency of insulating materials and, thus, can expand its applications to the study of glass corrosion, perovskite oxide thin film characterization, and many other systems of interest. PMID:25953490

  10. Small-Angle Fibre Diffraction Studies of Cornela Matrix Structure: A Depth-Profiled Investigation of the Human Eye-Bank Cornea

    SciTech Connect

    Quantock,A.; Boote, C.; Young, R.; Hayes, S.; Tanioka, H.; Kawasaki, S.; Ohta, N.; Lida, T.; Yagi, N.; et al.

    2007-01-01

    In the cornea of the eye light transmission is facilitated by the regular arrangement and uniform diameter of collagen fibrils that constitute the bulk of the extracellular corneal matrix. Matrix architecture, in turn, is believed to be governed by interactions between collagen fibrils and proteoglycan molecules modified with sulfated glycosaminoglycan side chains. Here, we outline the contribution made by small-angle X-ray scattering studies of the cornea in understanding the role of sulfated glycosaminoglycans in the control of collagen architecture in cornea, and present new depth-profiled microbeam data from swollen human eye-bank corneas that indicate no significant change in collagen fibril diameter throughout the tissue, but a lower collagen interfibrillar spacing in the anterior-most stromal regions compared with the ultrastructure of the deeper cornea.

  11. ChiMS: Open-source instrument control software platform on LabVIEW for imaging/depth profiling mass spectrometers

    PubMed Central

    Cui, Yang; Hanley, Luke

    2015-01-01

    ChiMS is an open-source data acquisition and control software program written within LabVIEW for high speed imaging and depth profiling mass spectrometers. ChiMS can also transfer large datasets from a digitizer to computer memory at high repetition rate, save data to hard disk at high throughput, and perform high speed data processing. The data acquisition mode generally simulates a digital oscilloscope, but with peripheral devices integrated for control as well as advanced data sorting and processing capabilities. Customized user-designed experiments can be easily written based on several included templates. ChiMS is additionally well suited to non-laser based mass spectrometers imaging and various other experiments in laser physics, physical chemistry, and surface science. PMID:26133872

  12. ChiMS: Open-source instrument control software platform on LabVIEW for imaging/depth profiling mass spectrometers

    NASA Astrophysics Data System (ADS)

    Cui, Yang; Hanley, Luke

    2015-06-01

    ChiMS is an open-source data acquisition and control software program written within LabVIEW for high speed imaging and depth profiling mass spectrometers. ChiMS can also transfer large datasets from a digitizer to computer memory at high repetition rate, save data to hard disk at high throughput, and perform high speed data processing. The data acquisition mode generally simulates a digital oscilloscope, but with peripheral devices integrated for control as well as advanced data sorting and processing capabilities. Customized user-designed experiments can be easily written based on several included templates. ChiMS is additionally well suited to non-laser based mass spectrometers imaging and various other experiments in laser physics, physical chemistry, and surface science.

  13. Depth of maximum of air-shower profiles at the Pierre Auger Observatory. I. Measurements at energies above $$10^{17.8}$$ eV

    DOE PAGESBeta

    Aab, Alexander

    2014-12-31

    We report a study of the distributions of the depth of maximum, Xmax, of extensive air-shower profiles with energies above 1017.8 eV as observed with the fluorescence telescopes of the Pierre Auger Observatory. The analysis method for selecting a data sample with minimal sampling bias is described in detail as well as the experimental cross-checks and systematic uncertainties. Furthermore, we discuss the detector acceptance and the resolution of the Xmax measurement and provide parametrizations thereof as a function of energy. Finally, the energy dependence of the mean and standard deviation of the Xmax distributions are compared to air-shower simulations formore » different nuclear primaries and interpreted in terms of the mean and variance of the logarithmic mass distribution at the top of the atmosphere.« less

  14. Depth of maximum of air-shower profiles at the Pierre Auger Observatory. I. Measurements at energies above $10^{17.8}$ eV

    SciTech Connect

    Aab, Alexander

    2014-12-31

    We report a study of the distributions of the depth of maximum, Xmax, of extensive air-shower profiles with energies above 1017.8 eV as observed with the fluorescence telescopes of the Pierre Auger Observatory. The analysis method for selecting a data sample with minimal sampling bias is described in detail as well as the experimental cross-checks and systematic uncertainties. Furthermore, we discuss the detector acceptance and the resolution of the Xmax measurement and provide parametrizations thereof as a function of energy. Finally, the energy dependence of the mean and standard deviation of the Xmax distributions are compared to air-shower simulations for different nuclear primaries and interpreted in terms of the mean and variance of the logarithmic mass distribution at the top of the atmosphere.

  15. ChiMS: Open-source instrument control software platform on LabVIEW for imaging/depth profiling mass spectrometers.

    PubMed

    Cui, Yang; Hanley, Luke

    2015-06-01

    ChiMS is an open-source data acquisition and control software program written within LabVIEW for high speed imaging and depth profiling mass spectrometers. ChiMS can also transfer large datasets from a digitizer to computer memory at high repetition rate, save data to hard disk at high throughput, and perform high speed data processing. The data acquisition mode generally simulates a digital oscilloscope, but with peripheral devices integrated for control as well as advanced data sorting and processing capabilities. Customized user-designed experiments can be easily written based on several included templates. ChiMS is additionally well suited to non-laser based mass spectrometers imaging and various other experiments in laser physics, physical chemistry, and surface science. PMID:26133872

  16. Argon Cluster Sputtering Source for ToF-SIMS Depth Profiling of Insulating Materials: High Sputter Rate and Accurate Interfacial Information

    NASA Astrophysics Data System (ADS)

    Wang, Zhaoying; Liu, Bingwen; Zhao, Evan W.; Jin, Ke; Du, Yingge; Neeway, James J.; Ryan, Joseph V.; Hu, Dehong; Zhang, Kelvin H. L.; Hong, Mina; Le Guernic, Solenne; Thevuthasan, Suntharampilai; Wang, Fuyi; Zhu, Zihua

    2015-08-01

    The use of an argon cluster ion sputtering source has been demonstrated to perform superiorly relative to traditional oxygen and cesium ion sputtering sources for ToF-SIMS depth profiling of insulating materials. The superior performance has been attributed to effective alleviation of surface charging. A simulated nuclear waste glass (SON68) and layered hole-perovskite oxide thin films were selected as model systems because of their fundamental and practical significance. Our results show that high sputter rates and accurate interfacial information can be achieved simultaneously for argon cluster sputtering, whereas this is not the case for cesium and oxygen sputtering. Therefore, the implementation of an argon cluster sputtering source can significantly improve the analysis efficiency of insulating materials and, thus, can expand its applications to the study of glass corrosion, perovskite oxide thin film characterization, and many other systems of interest.

  17. Tectonic and climatic control on terrace formation: Coupling in situ produced 10Be depth profiles and luminescence approach, Danube River, Hungary, Central Europe

    NASA Astrophysics Data System (ADS)

    Ruszkiczay-Rüdiger, Zsófia; Braucher, Régis; Novothny, Ágnes; Csillag, Gábor; Fodor, László; Molnár, Gábor; Madarász, Balázs

    2016-01-01

    The terrace sequence of the Hungarian part of the Danube valley preserves a record of varying tectonic uplift rates along the river course and throughout several climate stages. To establish the chronology of formation of these terraces, two different dating methods were used on alluvial terraces: exposure age dating using in situ produced cosmogenic 10Be and luminescence dating. Using Monte Carlo approach to model the denudation rate-corrected exposure ages, in situ produced cosmogenic 10Be samples originated from vertical depth profiles enabled the determination of both the exposure time and the denudation rate. Post-IR IRSL measurements were carried out on K-feldspar samples to obtain the ages of sedimentation. The highest terrace horizon remnants of the study area provided a best estimate erosion-corrected minimum 10Be exposure age of >700 ka. We propose that the abandonment of the highest terrace of the Hungarian Danube valley was triggered by the combined effect of the beginning tectonic uplift and the onset of major continental glaciations of Quaternary age (around MIS 22). For the lower terraces it was possible to reveal close correlation with MIS stages using IRSL ages. The new chronology enabled the distinction of tIIb (∼90 ka; MIS 5b-c) and tIIIa (∼140 ka; MIS 6) in the study area. Surface denudation rates were well constrained by the cosmogenic 10Be depth profiles between 5.8 m/Ma and 10.0 m/Ma for all terraces. The calculated maximum incision rates of the Danube relevant for the above determined >700 ka time span were increasing from west (<0.06 mm/a) to east (<0.13 mm/a), toward the more elevated Transdanubian Range. Late Pleistocene incision rates derived from the age of the low terraces (∼0.13-0.15 mm/a) may suggest a slight acceleration of uplift towards present.

  18. Argon Cluster Sputtering Source for ToF-SIMS Depth Profiling of Insulating Materials: High Sputter Rate and Accurate Interfacial Information

    SciTech Connect

    Wang, Zhaoying; Liu, Bingwen; Zhao, Evan; Jin, Ke; Du, Yingge; Neeway, James J.; Ryan, Joseph V.; Hu, Dehong; Zhang, Hongliang; Hong, Mina; Le Guernic, Solenne; Thevuthasan, Suntharampillai; Wang, Fuyi; Zhu, Zihua

    2015-08-01

    For the first time, the use of an argon cluster ion sputtering source has been demonstrated to perform superiorly relative to traditional oxygen and cesium ion sputtering sources for ToF-SIMS depth profiling of insulating materials. The superior performance has been attributed to effective alleviation of surface charging. A simulated nuclear waste glass, SON68, and layered hole-perovskite oxide thin films were selected as model systems due to their fundamental and practical significance. Our study shows that if the size of analysis areas is same, the highest sputter rate of argon cluster sputtering can be 2-3 times faster than the highest sputter rates of oxygen or cesium sputtering. More importantly, high quality data and high sputter rates can be achieved simultaneously for argon cluster sputtering while this is not the case for cesium and oxygen sputtering. Therefore, for deep depth profiling of insulating samples, the measurement efficiency of argon cluster sputtering can be about 6-15 times better than traditional cesium and oxygen sputtering. Moreover, for a SrTiO3/SrCrO3 bi-layer thin film on a SrTiO3 substrate, the true 18O/16O isotopic distribution at the interface is better revealed when using the argon cluster sputtering source. Therefore, the implementation of an argon cluster sputtering source can significantly improve the measurement efficiency of insulating materials, and thus can expand the application of ToF-SIMS to the study of glass corrosion, perovskite oxide thin films, and many other potential systems.

  19. Elemental depth profiling in Cu(In, Ga)Se 2 solar cells using micro-PIXE on a bevelled section

    NASA Astrophysics Data System (ADS)

    Spemann, D.; Otte, K.; Lorenz, M.; Butz, T.

    2005-04-01

    Cu(In, Ga)Se2 (CIGS) solar cells deposited on polyimide foils by the Solarion company in a web-coater based process using sputter and evaporation techniques were investigated in the ion beam laboratory LIPSION of the University of Leipzig by means of Rutherford Backscattering Spectrometry (RBS) and Particle Induced X-ray Emission (PIXE) using a 2.25 MeV proton microbeam. From these measurements the composition of the absorber as well as the lateral homogeneity and the film thicknesses of the individual layers of the solar cell could be determined under some reasonable assumptions. Quantitative depth profiling of the individual elements was performed by micro-PIXE measurements on a bevelled section of a CIGS solar cell prepared by ion beam etching. It revealed small concentration-depth-gradients for Cu, In, Ga and Se within the CIGS absorber layer. Furthermore, a remarkable amount of Cd from the overlying CdS buffer layer was found to be present in the absorber layer. Secondary Neutral Mass Spectrometry (SNMS) measurements were applied on the same samples for comparison.

  20. Differential laser absorption spectrometry for global profiling of tropospheric carbon dioxide: selection of optimum sounding frequencies for high-precision measurements.

    PubMed

    Menzies, Robert T; Tratt, David M

    2003-11-20

    We discuss the spectroscopic requirements for a laser absorption spectrometer (LAS) approach to high-precision carbon dioxide (CO2) measurements in the troposphere. Global-scale, high-precision CO2 measurements are highly desirable in an effort to improve understanding and quantification of the CO2 sources and sinks and their impact on global climate. We present differential absorption sounding characteristics for selected LAS transmitter laser wavelengths, emphasizing the effects of atmospheric temperature profile uncertainties. Candidate wavelengths for lower-troposphere measurements are identified in the CO2 bands centered near 1.57, 1.60, and 2.06 microm. PMID:14658457

  1. Interstitial oxygen related defects and nanovoids in Au implanted a-SiO2 glass depth profiled by positron annihilation spectroscopy

    NASA Astrophysics Data System (ADS)

    Ravelli, L.; Macchi, C.; Mariazzi, S.; Mazzoldi, P.; Egger, W.; Hugenschmidt, C.; Somoza, A.; Brusa, R. S.

    2015-12-01

    Samples of amorphous silica were implanted with Au ions at an energy of 190 keV and fluences of 1× {{10}14} ions cm-2and 5× {{10}14} ions cm-2 at room temperature. The damage produced by ion implantation and its evolution with the thermal treatment at 800 °C for one hour in nitrogen atmosphere was depth profiled using three positron annihilation techniques: Doppler broadening spectroscopy, positron annihilation lifetime spectroscopy and coincidence Doppler broadening spectroscopy. Around the ion projected range of {{R}\\text{p}}=67 nm, a size reduction of the silica matrix intrinsic nanovoids points out a local densification of the material. Oxygen related defects were found to be present at depths four times the ion projected range, showing a high mobility of oxygen molecules from the densified and stressed region towards the bulk. The 800 °C thermal treatment leads to a recovery of the silica intrinsic nanovoids only in the deeper damaged region and the defect distribution, probed by positrons, shrinks around the ion projected range where the Au atoms aggregate. Open volume defects at the interface between Au and the amorphous matrix were evidenced in both the as implanted and in the thermal treated samples. A practically complete disappearance of the intrinsic nanovoids was observed around {{R}\\text{p}} when the implantation fluence was increased by two orders of magnitude (3× {{10}16} ions cm-2). In this case, the oxygen defects move to a depth five times larger than {{R}\\text{p}} .

  2. Analysis of small field percent depth dose and profiles: Comparison of measurements with various detectors and effects of detector orientation with different jaw settings.

    PubMed

    Godson, Henry Finlay; Ravikumar, M; Sathiyan, S; Ganesh, K M; Ponmalar, Y Retna; Varatharaj, C

    2016-01-01

    The advent of modern technologies in radiotherapy poses an increased challenge in the determination of dosimetric parameters of small fields that exhibit a high degree of uncertainty. Percent depth dose and beam profiles were acquired using different detectors in two different orientations. The parameters such as relative surface dose (D S), depth of dose maximum (D max), percentage dose at 10 cm (D 10), penumbral width, flatness, and symmetry were evaluated with different detectors. The dosimetric data were acquired for fields defined by jaws alone, multileaf collimator (MLC) alone, and by MLC while the jaws were positioned at 0, 0.25, 0.5, and 1.0 cm away from MLC leaf-end using a Varian linear accelerator with 6 MV photon beam. The accuracy in the measurement of dosimetric parameters with various detectors for three different field definitions was evaluated. The relative D S(38.1%) with photon field diode in parallel orientation was higher than electron field diode (EFD) (27.9%) values for 1 cm ×1 cm field. An overestimation of 5.7% and 8.6% in D 10 depth were observed for 1 cm ×1 cm field with RK ion chamber in parallel and perpendicular orientation, respectively, for the fields defined by MLC while jaw positioned at the edge of the field when compared to EFD values in parallel orientation. For this field definition, the in-plane penumbral widths obtained with ion chamber in parallel and perpendicular orientation were 3.9 mm, 5.6 mm for 1 cm ×1 cm field, respectively. Among all detectors used in the study, the unshielded diodes were found to be an appropriate choice of detector for the measurement of beam parameters in small fields. PMID:27051165

  3. Analysis of small field percent depth dose and profiles: Comparison of measurements with various detectors and effects of detector orientation with different jaw settings

    PubMed Central

    Godson, Henry Finlay; Ravikumar, M.; Sathiyan, S.; Ganesh, K. M.; Ponmalar, Y. Retna; Varatharaj, C.

    2016-01-01

    The advent of modern technologies in radiotherapy poses an increased challenge in the determination of dosimetric parameters of small fields that exhibit a high degree of uncertainty. Percent depth dose and beam profiles were acquired using different detectors in two different orientations. The parameters such as relative surface dose (DS), depth of dose maximum (Dmax), percentage dose at 10 cm (D10), penumbral width, flatness, and symmetry were evaluated with different detectors. The dosimetric data were acquired for fields defined by jaws alone, multileaf collimator (MLC) alone, and by MLC while the jaws were positioned at 0, 0.25, 0.5, and 1.0 cm away from MLC leaf-end using a Varian linear accelerator with 6 MV photon beam. The accuracy in the measurement of dosimetric parameters with various detectors for three different field definitions was evaluated. The relative DS(38.1%) with photon field diode in parallel orientation was higher than electron field diode (EFD) (27.9%) values for 1 cm ×1 cm field. An overestimation of 5.7% and 8.6% in D10 depth were observed for 1 cm ×1 cm field with RK ion chamber in parallel and perpendicular orientation, respectively, for the fields defined by MLC while jaw positioned at the edge of the field when compared to EFD values in parallel orientation. For this field definition, the in-plane penumbral widths obtained with ion chamber in parallel and perpendicular orientation were 3.9 mm, 5.6 mm for 1 cm ×1 cm field, respectively. Among all detectors used in the study, the unshielded diodes were found to be an appropriate choice of detector for the measurement of beam parameters in small fields. PMID:27051165

  4. Niobium nitride films formed by rapid thermal processing (RTP): a study of depth profiles and interface reactions by complementary analytical techniques.

    PubMed

    Berendes, A; Brunkahl, O; Angelkort, C; Bock, W; Hofer, F; Warbichler, P; Kolbesen, B O

    2004-06-01

    The nitridation of niobium films approximately 250 and 650 nm thick by rapid thermal processing (RTP) at 800 degrees C in molecular nitrogen or ammonia was investigated. The niobium films were deposited by electron beam evaporation on silicon substrates covered by a 100 or 300 nm thick thermally grown SiO(2) layer. In these investigations the reactivity of ammonia and molecular nitrogen was compared with regard to nitride formation and reaction with the SiO(2) substrate layer. The phases formed were characterized by X-ray diffraction (XRD). Depth profiles of the elements in the films were recorded by use of secondary neutral mass spectrometry (SNMS). Microstructure and spatial distribution of the elements were imaged by transmission electron microscopy (TEM) and energy-filtered TEM (EFTEM). Electron energy loss spectra (EELS) were taken at selected positions to discriminate between different nitride, oxynitride, and oxide phases. The results provide clear evidence of the expected higher reactivity of ammonia in nitride formation and reaction with the SiO(2) substrate layer. Outdiffusion of oxygen into the niobium film and indiffusion of nitrogen from the surface of the film result in the formation of oxynitride in a zone adjacent to the Nb/SiO(2) interface. SNMS profiles of nitrogen reveal a distinct tail which is attributed to enhanced diffusion of nitrogen along grain boundaries. PMID:15098081

  5. Characterisation of natural organic matter (NOM) in depth profile of Mediterranean Sea by 3D-Fluorescence following with PARAFAC treatment

    NASA Astrophysics Data System (ADS)

    Huiyu, Z.; Durrieu, G.; Redon, R.; Heimbuerger, L.; Mounier, S.

    2009-12-01

    A periodic series of samplings have made during one year(2008) organized by Ifremer into the central Ligurian Sea(DYFAMED site, 43°25’N, 07°52’E, Mediterranean Sea). Spectra were mesured by spectrofluorimetry(HITACHI 4500) at excitation wavelengths from 250nm to 500nm and emission wavelengths from 200nm to 550nm, both wavelength slits for 5nm, scan speed is 2400nm/min. Parallel factors analysis(PARAFAC) software is a powerful statistical technique to treat the 3D-fluorescence spectra leading to the decomposition by a number of independent fluorescent compounds 1 and 2. Found 4 fluorescent components representing the fluorescence maxima of previously identified moieties: [Tyr] maximal excitation wavelength and emission wavelength 265nm/305nm (tyrosine-like); [Trp] maximal λEX/λEM=280nm/340nm(Peak T, tryptophan-like group); [M] maximal λEX/λEM=295nm/410nm(Peak M, marine humic-like substance) and a double maximum component [CA] with maximal λEX/λEM=335nm/445nm(Peak C, visible humic-like group) and λEX/λEM=250nm/445nm(Peak A, UV humic-like substance). Fluorescence contribution of each component at different logarithmic depths(Fig.2) shows that the most concentrated fluorophores zone is deeper than 100m, which is different from the results of dissolved organic carbon(DOC) concentration which the most concentrated zone is on the seasurface(B.Avril,2002).The humic-like substances are generally less fluorescent, particularly the M compound. An important peak contribution of marine humic-like substance has appeared in May at the profound 100m and 2200m, although the other fluorophores kept their values reasonable. The intensity maxima was closed to 100m, while an augmentation of protein substances in the deep sea(about 400 m) following by a shut immediate at 600 m in the months July, August and September. It is probably due to the sufficient heat from the sea surface; micro-organism could modify their position in the depth profile in the seawater. Thanks to

  6. Joint pre-stack depth migration and travel-time tomography applied to a deep seismic profile across the northern Barents Sea igneous province

    NASA Astrophysics Data System (ADS)

    Minakov, Alexander; Faleide, Jan Inge; Sakulina, Tamara; Krupnova, Natalia; Dergunov, Nikolai

    2015-04-01

    The mainly Permo-Triassic North Barents Sea Basin is considered as a superdeep intracratonic basin containing over 20 km of sedimentary material. This basin was strongly affected by magmatism attributed to the formation of the Early Cretaceous High Arctic Large Igneous Province. Dolerite dikes, sills, and lava flows are observed in the northern Barents Sea and on the islands of Svalbard and Franz Josef Land. Some dike swarms can be traced over hundreds of kilometers using high-resolution airborne magnetic data. In the North Barents Sea Basin, the dikes fed giant sill complex emplaced into organic-rich Triassic siliciclastic rocks. The sill complex creates a major challenge for seismic imaging masking the underlying strata. In this contribution, we first perform refraction and reflection travel-time tomography using wide-angle ocean-bottom seismometer data (with receivers deployed every 10 km) along the 4-AR profile (Sakulina et al. 2007, Ivanova et al. 2011). The resulting tomographic model is then used to construct a background velocity model for the pre-stack depth migration. We show that the use of a combined velocity model for the time and depth imaging based on travel-time tomography and RMS velocities constitutes a substantial improvement with respect to a standard processing workflow providing a more coherent seismic structure of this volcanic province. The interpretation of multichannel seismic and high-resolution magnetic data together with P-wave velocity and density anomalies allow to create a model for the system of magmatic feeders in the crystalline basement of the northern Barents Sea region. Sakulina, T.S., Verba, M.L., Ivanova, N.M., Krupnova, N.A., Belyaev I.V., 2007. Deep structure of the north Barents-Kara Region along 4AR transect (Taimyr Peninsula - Franz Joseph Land). In: Models of the Earth's crust and upper mantle after deep seismic profiling. Proceedings of the international scientific-practical seminar. Rosnedra, VSEGEI. St

  7. Improvement of the gas cluster ion beam-(GCIB)-based molecular secondary ion mass spectroscopy (SIMS) depth profile with O2(+) cosputtering.

    PubMed

    Chu, Yi-Hsuan; Liao, Hua-Yang; Lin, Kang-Yi; Chang, Hsun-Yun; Kao, Wei-Lun; Kuo, Ding-Yuan; You, Yun-Wen; Chu, Kuo-Jui; Wu, Chen-Yi; Shyue, Jing-Jong

    2016-04-21

    Over the last decade, cluster ion beams have displayed their capability to analyze organic materials and biological specimens. Compared with atomic ion beams, cluster ion beams non-linearly enhance the sputter yield, suppress damage accumulation and generate high mass fragments during sputtering. These properties allow successful Secondary Ion Mass Spectroscopy (SIMS) analysis of soft materials beyond the static limit. Because the intensity of high mass molecular ions is intrinsically low, enhancing the intensity of these secondary ions while preserving the sample in its original state is the key to highly sensitive molecular depth profiles. In this work, bulk poly(ethylene terephthalate) (PET) was used as a model material and analyzed using Time-of-Flight SIMS (ToF-SIMS) with a pulsed Bi3(2+) primary ion. The optimized hardware of a 10 kV Ar2500(+) Gas Cluster Ion Beam (GCIB) with a low kinetic energy (200-500 V) oxygen ion (O2(+)) as a cosputter beam was employed for generating depth profiles and for examining the effect of beam parameters. The results were then quantitatively analyzed using an established erosion model. It was found that the ion intensity of the PET monomer ([M + H](+)) and its large molecular fragment ([M - C2H4O + H](+)) steadily declined during single GCIB sputtering, with distortion of the distribution information. However, under an optimized GCIB-O2(+) cosputter, the secondary ion intensity quickly reached a steady state and retained >95% intensity with respect to the pristine surface, although the damage cross-section was larger than that of single GCIB sputtering. This improvement was due to the oxidation of molecules and the formation of -OH groups that serve as proton donors to particles emitted from the surface. As a result, the ionization yield was enhanced and damage to the chemical structure was masked. Although O2(+) is known to alter the chemical structure and cause damage accumulation, the concurrently used GCIB could

  8. Laboratory investigation on the role of tubular shaped micro resonators phononic crystal insertion on the absorption coefficient of profiled sound absorber

    NASA Astrophysics Data System (ADS)

    Yahya, I.; Kusuma, J. I.; Harjana; Kristiani, R.; Hanina, R.

    2016-02-01

    This paper emphasizes the influence of tubular shaped microresonators phononic crystal insertion on the sound absorption coefficient of profiled sound absorber. A simple cubic and two different bodies centered cubic phononic crystal lattice model were analyzed in a laboratory test procedure. The experiment was conducted by using transfer function based two microphone impedance tube method refer to ASTM E-1050-98. The results show that sound absorption coefficient increase significantly at the mid and high-frequency band (600 - 700 Hz) and (1 - 1.6 kHz) when tubular shaped microresonator phononic crystal inserted into the tested sound absorber element. The increment phenomena related to multi-resonance effect that occurs when sound waves propagate through the phononic crystal lattice model that produce multiple reflections and scattering in mid and high-frequency band which increases the sound absorption coefficient accordingly

  9. N2O vertical profiles retrieved from ground-based solar absorption spectra taken at McMurdo station during austral spring of 1989

    SciTech Connect

    Liu, X.; Murcray, F.J.

    1995-01-01

    N2O can be a tracer of atmospheric air motion due to its long life time. Ground-based FTIR solar spectra contain information on the vertical distributions of N2O due to pressure broadening of absorption lines. The authors have combined the Chahine-Twomey` relaxation method with a line-by-line layer-by-layer radiative transfer code to retrieve N2O VMR profiles from ground based solar absorption spectra. The spectra were taken at McMurdo station during the austral spring of 1989 with a 0.02 wavenumber resolution FTIR spectrometer. Since N2O is released from troposphere and is photolyzed in the stratosphere, the line shape of its absorption is mainly due Lorentz broadening. The 0.02 wavenumber resolution is high enough for the authors to retrieve N2O VMR profiles up to 25 kilometers. Figures show a typical observed N2O solar spectrum near 1993.15 wavenumber and a calculated spectrum using the authors profile retrieval program. The best fit is obtained by iteratively adjusting N20 VMR profile according to the formulation of Chahine and Twomey. The lower tropospheric N2O VMR`s have an average value around 310 ppb. Correlations of the N2O contour with that of temperature shows interesting features of tropospheric and lower stratospheric air motions. The authors have also compared the total N2O column amounts retrieved from this profile retrieval method and from the PC version of the non-linear least square spectral fitting algorithm (SFIT). The temporal variations of the N2O total column amounts retrieved from the two methods show excellent correlation.

  10. Interpretation of Stratified Fill, Frost Depths, Water Tables, and Massive Ice within Multi-Frequency Ground-Penetrating Radar Profiles Recorded Beneath Highways in Interior Alaska

    NASA Astrophysics Data System (ADS)

    Arcone, S. A.

    2014-12-01

    Road Radar generally refers to ground-penetrating radar (GPR) surveys intended to investigate pavement construction using pulses centered above 1 GHz. In interior Alaska thick sand and gravel grading and its frozen state by late winter generally afford up to 10 m of signal penetration at lower frequencies. Consequently, this penetration potentially allows identification of pavement issues involving frost heave and thaw settlement, while the smooth surface allows assessment of GPR performance in permafrost areas under ideal survey conditions. Here I discuss profiles using pulse center frequencies from 50 to 360 MHz, recorded over sections of the Steese and Elliott Highways within and just north of Fairbanks, respectively, and of the Tok Highway near Glennallen. Construction fill is easily recognized by its stratification; where marginally present along the Elliott it is replaced by steeply dipping horizons from the underlying schist. The frost depth and water table horizons are recognized by phase attributes of the reflected pulse, as dictated by the contrasts present in dielectric permittivity, their relative depths, and their continuity. Undulating stratification in the sand and gravel fill indicates thaw settlement, as caused by the melting of buried massive ice. The Tok section reveals the top and likely the bottom of massive ice. Generally, signal penetration is greatly reduced beneath the water table and so the highest resolution, at 360 MHz, covers all horizons. There is rare evidence of a permafrost table because it is most likely masked or nearly coincident with the water table. Permafrost penetration in frozen silts is a long-standing problem for GPR, for which I discuss a possible cause related to Maxwell-Wagner dielectric relaxation losses associated with unfrozen water.

  11. Lidar Ratios for Dust Aerosols Derived From Retrievals of CALIPSO Visible Extinction Profiles Constrained by Optical Depths from MODIS-Aqua and CALIPSO/CloudSat Ocean Surface Reflectance Measurements

    NASA Technical Reports Server (NTRS)

    Young, Stuart A.; Josset, Damien B.; Vaughan, Mark A.

    2010-01-01

    CALIPSO's (Cloud Aerosol Lidar Infrared Pathfinder Satellite Observations) analysis algorithms generally require the use of tabulated values of the lidar ratio in order to retrieve aerosol extinction and optical depth from measured profiles of attenuated backscatter. However, for any given time or location, the lidar ratio for a given aerosol type can differ from the tabulated value. To gain some insight as to the extent of the variability, we here calculate the lidar ratio for dust aerosols using aerosol optical depth constraints from two sources. Daytime measurements are constrained using Level 2, Collection 5, 550-nm aerosol optical depth measurements made over the ocean by the MODIS (Moderate Resolution Imaging Spectroradiometer) on board the Aqua satellite, which flies in formation with CALIPSO. We also retrieve lidar ratios from night-time profiles constrained by aerosol column optical depths obtained by analysis of CALIPSO and CloudSat backscatter signals from the ocean surface.

  12. Zircon U-Pb and trace element zoning characteristics in an anatectic granulite domain: Insights from LASS-ICP-MS depth profiling

    NASA Astrophysics Data System (ADS)

    Marsh, Jeffrey H.; Stockli, Daniel F.

    2015-12-01

    Understanding the geochemical characteristics of metamorphic zircon, and how they may be modified by recrystallization processes, is fundamental to defining the timescales of tectonic processes affecting continental lithosphere. We utilize laser ablation split-stream (LASS)-ICP-MS depth-profiling analysis to obtain a continuous rim-to-core record of the U-Pb ages and trace-element composition preserved within variably recrystallized zircon from different rock types within a well-studied granulite domain in the western Grenville Province, Canada. Detailed analysis of the depth-resolved signal enables definition of chemically distinct (homogeneous) internal domains and heterogeneous intervening zones that can generally be correlated with textural features observed in CL. Three age populations have been distinguished within the ~ 35 μm deep profiles that correlate well with the established timing of protolith formation, granulite-facies metamorphism, and amphibolite-facies shearing, respectively. The U-Pb isotopic system and Th/U ratios in much of the crystal interiors have undergone considerable modification, as evidenced by a linear correlation between 207Pb/206Pb age and Th/U ratio. Interior and rim domains commonly contain blurred or faded oscillatory zoning patterns, suggesting that solid-state recrystallization is at least partially responsible for the modified U-Th-Pb composition. A number of systematic trends in trace element composition are also observed between interior domains and recrystallized rims, including 1) decreased Th/U (to ~ 0.1), 2) tighter clustering of Hf concentrations, 3) decreased total REE, 4) unchanged Eu anomalies, and 5) a widened spread of HREE enrichment values (YbN/GdN). Both YbN/GdN vs. Th/U and U/Ce vs. Th plots show increasing degree of compositional differentiation from protolith zircon as a function of metamorphic reworking processes (i.e. sample type). The transition zones between interior and rim domains exhibit textural

  13. THE RADIAL AND AZIMUTHAL PROFILES OF Mg II ABSORPTION AROUND 0.5 < z < 0.9 zCOSMOS GALAXIES OF DIFFERENT COLORS, MASSES, AND ENVIRONMENTS

    SciTech Connect

    Bordoloi, R.; Lilly, S. J.; Knobel, C.; Kampczyk, P.; Carollo, C. M.; Bolzonella, M.; Zucca, E.; Zamorani, G.; Bardelli, S.; Iovino, A.; Contini, T.; Kneib, J.-P.; Le Fevre, O.; Renzini, A.; Scodeggio, M.; Balestra, I.; Bongiorno, A.; Caputi, K.; Cucciati, O.; and others

    2011-12-10

    We map the radial and azimuthal distribution of Mg II gas within {approx} 200 kpc (physical) of {approx} 4000 galaxies at redshifts 0.5 < z < 0.9 using co-added spectra of more than 5000 background galaxies at z > 1. We investigate the variation of Mg II rest-frame equivalent width (EW) as a function of the radial impact parameter for different subsets of foreground galaxies selected in terms of their rest-frame colors and masses. Blue galaxies have a significantly higher average Mg II EW at close galactocentric radii as compared to the red galaxies. Among the blue galaxies, there is a correlation between Mg II EW and galactic stellar mass of the host galaxy. We also find that the distribution of Mg II absorption around group galaxies is more extended than that for non-group galaxies, and that groups as a whole have more extended radial profiles than individual galaxies. Interestingly, these effects can be satisfactorily modeled by a simple superposition of the absorption profiles of individual member galaxies, assuming that these are the same as those of non-group galaxies, suggesting that the group environment may not significantly enhance or diminish the Mg II absorption of individual galaxies. We show that there is a strong azimuthal dependence of the Mg II absorption within 50 kpc of inclined disk-dominated galaxies, indicating the presence of a strongly bipolar outflow aligned along the disk rotation axis. There is no significant dependence of Mg II absorption on the apparent inclination angle of disk-dominated galaxies.

  14. Atomic-resolved depth profile of strain and cation intermixing around LaAlO3/SrTiO3 interfaces.

    PubMed

    Zaid, H; Berger, M H; Jalabert, D; Walls, M; Akrobetu, R; Fongkaew, I; Lambrecht, W R L; Goble, N J; Gao, X P A; Berger, P; Sehirlioglu, A

    2016-01-01

    Novel behavior has been observed at the interface of LaAlO3/SrTiO3 heterostructures such as two dimensional metallic conductivity, magnetic scattering and superconductivity. However, both the origins and quantification of such behavior have been complicated due to an interplay of mechanical, chemical and electronic factors. Here chemical and strain profiles near the interface of LaAlO3/SrTiO3 heterostructures are correlated. Conductive and insulating samples have been processed, with thicknesses respectively above and below the commonly admitted conductivity threshold. The intermixing and structural distortions within the crystal lattice have been quantitatively measured near the interface with a depth resolution of unit cell size. A strong link between intermixing and structural distortions at such interfaces is highlighted: intermixing was more pronounced in the hetero-couple with conductive interface, whereas in-plane compressive strains extended deeper within the substrate of the hetero-couple with the insulating interface. This allows a better understanding of the interface local mechanisms leading to the conductivity. PMID:27301609

  15. Atomic-resolved depth profile of strain and cation intermixing around LaAlO3/SrTiO3 interfaces

    PubMed Central

    Zaid, H.; Berger, M. H.; Jalabert, D.; Walls, M.; Akrobetu, R.; Fongkaew, I.; Lambrecht, W. R. L.; Goble, N. J.; Gao, X. P. A.; Berger, P.; Sehirlioglu, A.

    2016-01-01

    Novel behavior has been observed at the interface of LaAlO3/SrTiO3 heterostructures such as two dimensional metallic conductivity, magnetic scattering and superconductivity. However, both the origins and quantification of such behavior have been complicated due to an interplay of mechanical, chemical and electronic factors. Here chemical and strain profiles near the interface of LaAlO3/SrTiO3 heterostructures are correlated. Conductive and insulating samples have been processed, with thicknesses respectively above and below the commonly admitted conductivity threshold. The intermixing and structural distortions within the crystal lattice have been quantitatively measured near the interface with a depth resolution of unit cell size. A strong link between intermixing and structural distortions at such interfaces is highlighted: intermixing was more pronounced in the hetero-couple with conductive interface, whereas in-plane compressive strains extended deeper within the substrate of the hetero-couple with the insulating interface. This allows a better understanding of the interface local mechanisms leading to the conductivity. PMID:27301609

  16. Hadean Crustal Processes Revealed from Oxygen Isotopes and U-Th-Pb Depth Profiling of Pre-4.0 Ga Detrital Zircons from Western Australia

    NASA Technical Reports Server (NTRS)

    Trail, D.; Mojzsis, S. J.; Harrison, T. M.

    2005-01-01

    Because physical and chemical processes of the past are determined from analysis of a preserved geologic record, little is known about terrestrial crustal processes of the first 500 Ma during the so-called Hadean Eon. What is known from direct measurements has been derived almost exclusively from the study of greater than 4.0 Ga detrital zircons from the Jack Hills, Western Australia. The geochemistry of these zircons has direct application to understanding the origin and evolution of the rocks during the Hadean because: (i) U-Th-Pb age determinations by ion microprobe suggests the presence of crust as early as 4.37 Ga, or shortly after lunar formation; (ii) high-resolution U-Th-Pb zircon depth profiles reported here reveal several episodes of zircon growth in the Hadean previously unrecognized; (iii) core regions of pre-4.0 Ga zircons with igneous compositions are enriched in O-18 and contain metaluminous and peraluminous mineral inclusions, both features indicative of S-type grainitod protoliths. Study of these ancient zircons provides a unique window into the first half billion years that permits assessment of the potential of the Hadean Earth to host an emergent biosphere.

  17. TOF-SIMS Analysis of Sea Salt Particles: Imaging and Depth Profiling in the Discovery of an Unrecognized Mechanism for pH Buffering

    SciTech Connect

    Gaspar, Dan J.; Laskin, Alexander; Wang, Weihong; Hunt, Sherri W.; Finlayson-Pitts, Barbara J.

    2004-06-15

    As part of a broader effort at understanding the chemistry of sea salt particles, we have performed time-of-flight secondary ion mass spectroscopy (TOF-SIMS) analysis of individual sea salt particles deposited on a transmission electron microscopy (TEM) grid. Environmental scanning electron microscopy (ESEM) and TOF-SIMS analysis have, in conjunction with OH exposure studies, led to the discovery of an unrecognized buffering mechanism in the uptake and oxidation of SO2 in sea salt particles in the marine boundary layer. This chemistry may resolve several discrepancies in the atmospheric chemistry literature. Several challenges during the acquisition and interpretation of both imaging and depth profiling data on specific particles on the TEM grid identified by the ESEM were overcome. A description of the analysis challenges and the solutions ultimately developed to them is presented here, along with an account of how the TOF-SIMS data were incorporated into the overall research effort. Several issues unique to the analysis of high aspect ratio particles are addressed.[1

  18. TOF-SIMS Analysis of Sea Salt Particles: Imaging and Depth Profiling in the Discovery of an Unrecogized Mechanism for pH Buffering

    SciTech Connect

    Gaspar, Dan J.; Laskin, Alexander; Wang, Weihong; Hunt, Sherri W.; Finlayson-Pitts, Barbara J.

    2004-06-15

    As part of a broader effort at understanding the chemistry of sea salt particles, we have performed time-of-flight secondary ion mass spectroscopy (TOF-SIMS) analysis of individual sea salt particles deposited on a transmission electron microscopy (TEM) grid. Environmental scanning electron microscopy (ESEM) and TOF-SIMS analysis have, in conjunction with OH exposure studies, led to the discovery of an unrecognised buffering mechanism in the uptake and oxidation of SO2 in sea salt particles in the marine boundary layer. This chemistry may resolve several discrepancies in the atmospheric chemistry literature. Several challenges during the acquisition and interpretation of both imaging and depth profiling data on specific particles on the TEM grid identified by the ESEM were overcome. A description of the analysis challenges and the solutions ultimately developed to them is presented here, along with an account of how the TOF-SIMS data were incorporated into the overall research effort. Several issues unique to the analysis of high aspect ratio particles are addressed.[1

  19. Atomic-resolved depth profile of strain and cation intermixing around LaAlO3/SrTiO3 interfaces

    NASA Astrophysics Data System (ADS)

    Zaid, H.; Berger, M. H.; Jalabert, D.; Walls, M.; Akrobetu, R.; Fongkaew, I.; Lambrecht, W. R. L.; Goble, N. J.; Gao, X. P. A.; Berger, P.; Sehirlioglu, A.

    2016-06-01

    Novel behavior has been observed at the interface of LaAlO3/SrTiO3 heterostructures such as two dimensional metallic conductivity, magnetic scattering and superconductivity. However, both the origins and quantification of such behavior have been complicated due to an interplay of mechanical, chemical and electronic factors. Here chemical and strain profiles near the interface of LaAlO3/SrTiO3 heterostructures are correlated. Conductive and insulating samples have been processed, with thicknesses respectively above and below the commonly admitted conductivity threshold. The intermixing and structural distortions within the crystal lattice have been quantitatively measured near the interface with a depth resolution of unit cell size. A strong link between intermixing and structural distortions at such interfaces is highlighted: intermixing was more pronounced in the hetero-couple with conductive interface, whereas in-plane compressive strains extended deeper within the substrate of the hetero-couple with the insulating interface. This allows a better understanding of the interface local mechanisms leading to the conductivity.

  20. Aging of Zerovalent Iron in Synthetic Groundwater: X-ray Photoelectron Spectroscopy Depth Profiling Characterization and Depassivation with Uniform Magnetic Field.

    PubMed

    Xu, Hanyang; Sun, Yuankui; Li, Jinxiang; Li, Fengmin; Guan, Xiaohong

    2016-08-01

    Scanning electron microscopy (SEM), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) depth profiling were employed to characterize the aged zerovalent iron (AZVI) samples incubated in synthetic groundwater. The AZVI samples prepared under different conditions exhibited the passive layers of different morphologies, amounts, and constituents. Owing to the accumulation of iron oxides on their surface, all the prepared AZVI samples were much less reactive than the pristine ZVI for Se(IV) removal. However, the reactivity of all AZVI samples toward Se(IV) sequestration could be significantly enhanced by applying a uniform magnetic field (UMF). Moreover, the flux intensity of UMF necessary to depassivate an AZVI sample was strongly dependent on the properties of its passive layer. The UMF of 1 mT was strong enough to restore the reactivity of the AZVI samples with Fe3O4 as the major constituent of the passive film or with a thin layer of α-Fe2O3 and γ-FeOOH in the external passive film. The flux intensity of UMF necessary to depassivate the AZVI samples would increase to 2 mT or even 5 mT if the AZVI samples were covered with passive films being thicker, denser, and contained more γ-FeOOH and α-Fe2O3. Furthermore, increasing the flux intensity of UMF facilitated the reduction of Se(IV) to Se(0) by AZVI samples. PMID:27384928

  1. Potentials and pitfalls of depth profile (10Be), burial isochron (26Al/10Be) and palaeomagnetic techniques for dating Early Pleistocene terrace deposits of the Moselle valley (Germany)

    NASA Astrophysics Data System (ADS)

    Rixhon, Gilles; Cordier, Stéphane; May, Simon Matthias; Kelterbaum, Daniel; Szemkus, Nina; Keulertz, Rebecca; Dunai, Tibor; Binnie, Steven; Hambach, Ulrich; Scheidt, Stephanie; Brueckner, Helmut

    2016-04-01

    Throughout the river network of the Rhenish Massif the so-called main terraces complex (MTC) forms the morphological transition between a wide upper palaeovalley and a deeply incised lower valley. The youngest level of this complex (YMT), directly located at the edge of the incised valley, represents a dominant geomorphic feature; it is often used as a reference level to identify the beginning of the main middle Pleistocene incision episode (Demoulin & Hallot, 2009). Although the main terraces are particularly well preserved in the lower Moselle valley, a questionable age of ca. 800 ka is assumed for the YMT, mainly based on the uncertain extrapolation of controversially interpreted palaeomagnetic data obtained in the Rhine valley. In this study, we applied terrestrial cosmogenic nuclide (TCN) dating (10Be/26Al) and palaeomagnetic dating to Moselle fluvial sediments of the MTC. To unravel the spatio-temporal characteristics of the Pleistocene evolution of the valley, several sites along the lower Moselle were sampled following two distinct TCN dating strategies: depth profiles where the original terrace (palaeo-) surface is well preserved and did not experience a major post-depositional burial (e.g., loess cover); and the isochron technique, where the sediment thickness exceeds 4.5-5 m. One terrace deposit was sampled for both approaches (reference site). In addition, palaeomagnetic sampling was systematically performed in each terrace sampled for TCN measurements. The TCN dating techniques show contrasting results for our reference site. Three main issues are observed for the depth profile method: (i) an inability of the modeled profile to constrain the 10Be concentration of the uppermost sample; (ii) an overestimated density value as model output; and (iii) a probable concentration steady state of the terrace deposits. By contrast, the isochron method yields a burial age estimate of 1.26 +0.29/-0.25 Ma, although one sample showed a depleted 26Al/10Be ratio

  2. Achieving an Accurate Surface Profile of a Photonic Crystal for Near-Unity Solar Absorption in a Super Thin-Film Architecture.

    PubMed

    Kuang, Ping; Eyderman, Sergey; Hsieh, Mei-Li; Post, Anthony; John, Sajeev; Lin, Shawn-Yu

    2016-06-28

    In this work, a teepee-like photonic crystal (PC) structure on crystalline silicon (c-Si) is experimentally demonstrated, which fulfills two critical criteria in solar energy harvesting by (i) its Gaussian-type gradient-index profile for excellent antireflection and (ii) near-orthogonal energy flow and vortex-like field concentration via the parallel-to-interface refraction effect inside the structure for enhanced light trapping. For the PC structure on 500-μm-thick c-Si, the average reflection is only ∼0.7% for λ = 400-1000 nm. For the same structure on a much thinner c-Si ( t = 10 μm), the absorption is near unity (A ∼ 99%) for visible wavelengths, while the absorption in the weakly absorbing range (λ ∼ 1000 nm) is significantly increased to 79%, comparing to only 6% absorption for a 10-μm-thick planar c-Si. In addition, the average absorption (∼94.7%) of the PC structure on 10 μm c-Si for λ = 400-1000 nm is only ∼3.8% less than the average absorption (∼98.5%) of the PC structure on 500 μm c-Si, while the equivalent silicon solid content is reduced by 50 times. Furthermore, the angular dependence measurements show that the high absorption is sustained over a wide angle range (θinc = 0-60°) for teepee-like PC structure on both 500 and 10-μm-thick c-Si. PMID:27258082

  3. Mars Ozone Absorption Line Shapes from Infrared Heterodyne Spectra Applied to GCM-Predicted Ozone Profiles and to MEX/SPICAM Column Retrievals

    NASA Astrophysics Data System (ADS)

    Fast, Kelly Elizabeth; Kostiuk, T.; Hewagama, T.; Livengood, T. A.; Delgado, J. D.; Annen, J.; Lefèvre, F.

    2008-09-01

    We present the application of infrared heterodyne line shapes of ozone on Mars to those produced by radiative transfer modeling of ozone profiles predicted by general circulation models (GCM), and to contemporaneous column abundances measured by Mars Express SPICAM. Ozone is an important tracer of photochemistry Mars’ atmosphere, serving as an observable with which to test predictions of photochemistry-coupled GCMs. Infrared heterodyne spectroscopy at 9.5 μm with spectral resolving power >1,000,000 is the only technique that can directly measure fully-resolved line shapes of Martian ozone features from the surface of the Earth. Measurements were made with Goddard Space Flight Center's Heterodyne Instrument for Planetary Wind And Composition (HIPWAC) at the NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawai'i on February 21-24 2008 UT at Ls=35°, on or near the MEX orbital path. The HIPWAC observations were used to test GCM predictions. For example, a GCM-generated ozone profile for 60°N 112°W was scaled so that a radiative transfer calculation of its absorption line shape matched an observed HIPWAC absorption feature at the same areographic position, local time, and season. The RMS deviation of the model from the data was slightly smaller for the GCM-generated profile than for a line shape produced by a constant-with-height profile, even though the total column abundances were the same, showing potential for testing and constraining GCM ozone profiles. The resulting ozone column abundance from matching the model to the HIPWAC line shape was 60% higher than that observed by SPICAM at the same areographic position one day earlier and 2.5 hours earlier in local time. This could be due to day-to-day, diurnal, or north polar region variability, or to measurement sensitivity to the ozone column and its distribution, and these possibilities will be explored. This work was supported by NASA's Planetary Astronomy Program.

  4. Mars Ozone Absorption Line Shapes from Infrared Heterodyne Spectra Applied to GCM-Predicted Ozone Profiles and to MEX/SPICAM Column Retrievals

    NASA Technical Reports Server (NTRS)

    Fast, Kelly E.; Kostiuk, T.; Annen, J.; Hewagama, T.; Delgado, J.; Livengood, T. A.; Lefevre, F.

    2008-01-01

    We present the application of infrared heterodyne line shapes of ozone on Mars to those produced by radiative transfer modeling of ozone profiles predicted by general circulation models (GCM), and to contemporaneous column abundances measured by Mars Express SPICAM. Ozone is an important tracer of photochemistry Mars' atmosphere, serving as an observable with which to test predictions of photochemistry-coupled GCMs. Infrared heterodyne spectroscopy at 9.5 microns with spectral resolving power >1,000,000 is the only technique that can directly measure fully-resolved line shapes of Martian ozone features from the surface of the Earth. Measurements were made with Goddard Space Flight Center's Heterodyne instrument for Planetary Wind And Composition (HIPWAC) at the NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii on February 21-24 2008 UT at Ls=35deg on or near the MEX orbital path. The HIPWAC observations were used to test GCM predictions. For example, a GCM-generated ozone profile for 60degN 112degW was scaled so that a radiative transfer calculation of its absorption line shape matched an observed HIPWAC absorption feature at the same areographic position, local time, and season. The RMS deviation of the model from the data was slightly smaller for the GCM-generated profile than for a line shape produced by a constant-with-height profile, even though the total column abundances were the same, showing potential for testing and constraining GCM ozone-profiles. The resulting ozone column abundance from matching the model to the HIPWAC line shape was 60% higher than that observed by SPICAM at the same areographic position one day earlier and 2.5 hours earlier in local time. This could be due to day-to-day, diurnal, or north polar region variability, or to measurement sensitivity to the ozone column and its distribution, and these possibilities will be explored. This work was supported by NASA's Planetary Astronomy Program.

  5. In situ produced 10Be depth profiles and luminescence data tracing climatic and tectonic control on terrace formation, Danube River, Central Europe, Hungary

    NASA Astrophysics Data System (ADS)

    Ruszkiczay-Rüdiger, Zsófia; Braucher, Régis; Novothny, Ágnes; Csillag, Gábor; Fodor, László; Molnár, Gábor; Madarász, Balázs; Aster Team

    2015-04-01

    The terrace sequence of the Hungarian part of the Danube valley preserves a record of varying tectonic uplift rates along the river course and throughout several climate stages. To establish the chronology of formation of these terraces, two different dating methods on alluvial terraces were used: 1) in situ produced cosmogenic 10Be, which yield the time of abandonment of the terrace and 2) luminescence dating, which provides burial ages of the sediment. In situ produced cosmogenic 10Be samples originated from vertical depth profiles to enable the determination of both the exposure time and the denudation rate at each locality. We used Monte Carlo approach to model the denudation rate-corrected exposure ages. Post-IR IRSL measurements were carried out on K-feldspar samples to obtain the ages of sedimentation. The highest and oldest terrace remnants (tIV-VI) yield a minimum 10Be exposure age of 800 ka close to MIS 22, the onset of major continental glaciations of Quaternary age, suggesting climatic signal of the abandonment of the uppermost terrace levels. For the lower terraces it was possible to reveal close correlation with MIS stages using IRSL ages. The new chronology enables the distinction of tIIb (60-110 ka; MIS 4-5d) and tIIIa (130-190 ka; MIS 6) in the study area. Surface denudation rates were well constrained by the cosmogenic 10Be depth profiles between 5.9 m/Ma and 10.0 m/Ma for all terraces. Maximum incision rates of the Danube were calculated for middle and late Pleistocene times. These rates were increasing from west to east, toward the more elevated Transdanubian Range from 0.05 mm/a to 0.12 mm/a. Incision rates derived from the age of the low terraces (0.13 mm/a) may suggest a slight acceleration of uplift towards present. Our research was supported by the OTKA PD83610, PD100315, NK60455, K062478, K83150 and F042799, the French-Hungarian Balaton-Tét Project (FR-32/2007; TÉT_11-2-2012-0005), the Bolyai János Scholarship of the Hungarian Academy

  6. Molecular Depth Profiling of Sucrose Films: A Comparative Study of C₆₀n⁺ Ions and Traditional Cs⁺ and O₂⁺ Ions

    SciTech Connect

    Zhu, Zihua; Nachimuthu, Ponnusamy; Lea, Alan S.

    2009-10-15

    Time-of-flight secondary ion mass spectrometry (ToF-SIMS) depth profiling of sucrose thin films were investigated using 10 keV C60+, 20 keV C602+, 30 keV C603+, 250 eV, 500 eV and 1000 eV Cs+ and O2+ as sputtering ions. With C60n+ ions, the molecular ion signal initially decreases, and reaches a steady-state that is about 38-51% of its original intensity, depending on the energy of the C60n+ ions. On the contrary, with Cs+ and O2+ sputtering, molecular ion signals decrease quickly to the noise level, even using low energy (250 eV) sputtering ions. In addition, the sucrose/Si interface by C60+ sputtering is much narrower than that of Cs+ and O2+ sputtering. To understand the mechanisms of sputtering-induced damage by these ions, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were used to characterize the bottoms of these sputter craters. XPS data show very little chemical change in the C60+ sputter crater, while considerable amorphous carbon was found in the O2+ and Cs+ sputter craters, indicating extensive decomposition of the sucrose molecules. AFM images show a very flat bottom in the C60+ sputter crater, while the Cs+ and O2+ sputter crater bottoms are significantly rougher than that of the C60+ sputter crater. Based on above data, we developed a simple model to explain different damage mechanisms during sputtering process.

  7. Summer depth distribution profiles of dissolved CO2 and O2 in shallow temperate lakes reveal trophic state and lake type specific differences.

    PubMed

    Laas, Alo; Cremona, Fabien; Meinson, Pille; Rõõm, Eva-Ingrid; Nõges, Tiina; Nõges, Peeter

    2016-10-01

    Knowledge about dissolved oxygen (DO) and carbon dioxide (CO2) distribution in lakes has increased considerably over the last decades. However, studies about high resolution dynamics of dissolved CO2 in different types of lakes over daily or weekly time scales are still very scarce. We measured summertime vertical DO and CO2 profiles at sub-hourly intervals during one week in eight Estonian lakes representing different lake types according to European Water Framework Directive. The lakes showed considerable differences in thermal stratification and vertical distribution of dissolved oxygen and CO2 as well as different diurnal dynamics over the measurement period. We observed a continuous CO2 supersaturation in the upper mixed layer of the alkalitrophic (calcareous groundwater-fed) lake and the dark soft-water lake showing them as CO2 emitting "chimneys" although with different underlying mechanisms. In three lake types strong undersaturation with CO2 occurred in the surface layer characterising them as CO2 sinks for the measurement period while in another three types the surface layer CO2 was mostly in equilibrium with the atmosphere. Factor analysis showed that DO% in the surface layer and the strength of its relationship with CO2% were positively related to alkalinity and negatively to trophic state and DOC gradients, whereas deeper lakes were characterised by higher surface concentration but smaller spatial and temporal variability of CO2. Multiple regression analysis revealed lake area, maximum depth and the light attenuation coefficient as variables affecting the largest number of gas regime indicators. We conclude that the trophic status of lakes in combination with type specific features such as morphometry, alkalinity and colour (DOC) determines the distribution and dynamics of dissolved CO2 and DO, which therefore may indicate functional differences in carbon cycling among lakes. PMID:27213672

  8. Expression Profile of Drug and Nutrient Absorption Related Genes in Madin-Darby Canine Kidney (MDCK) Cells Grown under Differentiation Conditions

    PubMed Central

    Quan, Yong; Jin, Yisheng; Faria, Teresa N.; Tilford, Charles A.; He, Aiqing; Wall, Doris A.; Smith, Ronald L.; Vig, Balvinder S.

    2012-01-01

    The expression levels of genes involved in drug and nutrient absorption were evaluated in the Madin-Darby Canine Kidney (MDCK) in vitro drug absorption model. MDCK cells were grown on plastic surfaces (for 3 days) or on Transwell® membranes (for 3, 5, 7, and 9 days). The expression profile of genes including ABC transporters, SLC transporters, and cytochrome P450 (CYP) enzymes was determined using the Affymetrix® Canine GeneChip®. Expression of genes whose probe sets passed a stringent confirmation process was examined. Expression of a few transporter (MDR1, PEPT1 and PEPT2) genes in MDCK cells was confirmed by RT-PCR. The overall gene expression profile was strongly influenced by the type of support the cells were grown on. After 3 days of growth, expression of 28% of the genes was statistically different (1.5-fold cutoff, p < 0.05) between the cells grown on plastic and Transwell® membranes. When cells were differentiated on Transwell® membranes, large changes in gene expression profile were observed during the early stages, which then stabilized after 5–7 days. Only a small number of genes encoding drug absorption related SLC, ABC, and CYP were detected in MDCK cells, and most of them exhibited low hybridization signals. Results from this study provide valuable reference information on endogenous gene expression in MDCK cells that could assist in design of drug-transporter and/or drug-enzyme interaction studies, and help interpret the contributions of various transporters and metabolic enzymes in studies with MDCK cells. PMID:24300234

  9. Infrared heterodyne spectroscopy of astronomical and laboratory sources at 8.5 micron. [absorption line profiles of nitrogen oxide and black body emission from Moon and Mars

    NASA Technical Reports Server (NTRS)

    Mumma, M.; Kostiuk, T.; Cohen, S.; Buhl, D.; Vonthuna, P. C.

    1974-01-01

    The first infrared heterodyne spectrometer using tuneable semiconductor (PbSe) diode lasers has been constructed and was used near 8.5 micron to measure absorption line profiles of N2O in the laboratory and black body emission from the Moon and from Mars. Spectral information was recorded over a 200 MHz bandwidth using an 8-channel filter bank. The resolution was 25 MHz and the minimum detectable (black body) power was 1 x 10 to the minus 16th power watts for 8 minutes of integration. The results demonstrate the usefulness of heterodyne spectroscopy for the study of remote and local sources in the infrared.

  10. Stratospheric N2O mixing ratio profile from high-resolution balloon-borne solar absorption spectra and laboratory spectra near 1880/cm

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Goldman, A.; Murcray, F. J.; Murcray, D. G.; Smith, M. A. H.; Seals, R. K., Jr.; Larsen, J. C.; Rinsland, P. L.

    1982-01-01

    A nonlinear least-squares fitting procedure is used to derive the stratospheric N2O mixing ratio profile from balloon-borne solar absorption spectra and laboratory spectra near 1880/cm. The atmospheric spectra analyzed here were recorded during sunset from a float altitude of 33 km with the University of Denver's 0.02/cm resolution interferometer near Alamogordo, N.M. (33 deg N) on Oct. 10, 1979. The laboratory data are used to determine the N2O line intensities. The measurements suggest an N2O mixing ratio of 264 ppbv near 15 km, decreasing to 155 ppbv near 28 km.

  11. Profiles.

    ERIC Educational Resources Information Center

    School Arts, 1979

    1979-01-01

    Profiles seven Black, Native American, and Chicano artists and art teachers: Hale A. Woodruff, Allan Houser, Luis Jimenez, Betrand D. Phillips, James E. Pate, I, and Fernando Navarro. This article is part of a theme issue on multicultural art. (SJL)

  12. Apparent Depth.

    ERIC Educational Resources Information Center

    Nassar, Antonio B.

    1994-01-01

    Discusses a well-known optical refraction problem where the depth of an object in a liquid is determined. Proposes that many texts incorrectly solve the problem. Provides theory, equations, and diagrams. (MVL)

  13. 24-hour human urine and serum profiles of bisphenol A: Evidence against sublingual absorption following ingestion in soup.

    PubMed

    Teeguarden, Justin G; Twaddle, Nathan C; Churchwell, Mona I; Yang, Xiaoxia; Fisher, Jeffrey W; Seryak, Liesel M; Doerge, Daniel R

    2015-10-15

    Extensive first-pass metabolism of ingested bisphenol A (BPA) in the gastro-intestinal tract and liver restricts blood concentrations of bioactive BPA to <1% of total BPA in humans and non-human primates. Absorption of ingested BPA through non-metabolizing tissues of the oral cavity, recently demonstrated in dogs, could lead to the higher serum BPA concentrations reported in some human biomonitoring studies. We hypothesized that the extensive interaction with the oral mucosa by a liquid matrix, like soup, relative to solid food or capsules, might enhance absorption through non-metabolizing oral cavity tissues in humans, producing higher bioavailability and higher serum BPA concentrations. Concurrent serum and urine concentrations of d6-BPA, and its glucuronide and sulfate conjugates, were measured over a 24hour period in 10 adult male volunteers following ingestion of 30μg d6-BPA/kg body weight in soup. Absorption of d6-BPA was rapid (t1/2=0.45h) and elimination of the administered dose was complete 24h post-ingestion, evidence against any tissue depot for BPA. The maximum serum d6-BPA concentration was 0.43nM at 1.6h after administration and represented <0.3% of total d6-BPA. Pharmacokinetic parameters, pharmacokinetic model simulations, and the significantly faster appearance half-life of d6-BPA-glucuronide compared to d6-BPA (0.29h vs 0.45h) were evidence against meaningful absorption of BPA in humans through any non-metabolizing tissue (<1%). This study confirms that typical exposure to BPA in food produces picomolar to subpicomolar serum BPA concentrations in humans, not nM concentrations reported in some biomonitoring studies. PMID:25620055

  14. Stratospheric NO and NO2 profiles at sunset from analysis of high-resolution balloon-borne infrared solar absorption spectra obtained at 33 deg N and calculations with a time-dependent photochemical model

    SciTech Connect

    Rinsland, C.P.; Boughner, R.E.; Larsen, J.C.; Goldman, A.

    1984-08-01

    Simultaneous stratospheric vertical profiles of NO and NO2 at sunset were derived from an analysis of infrared solar absorption spectra recorded from a float altitude of 33 km with an interferometer system during a balloon flight. A nonlinear least squares procedure was used to analyze the spectral data in regions of absorption by NO and NO2 lines. Normalized factors, determined from calculations of time dependent altitude profiles with a detailed photochemical model, were included in the onion peeling analysis to correct for the rapid diurnal changes in NO and NO2 concentrations with time near sunset. The CO2 profile was also derived from the analysis and is reported.

  15. Stratospheric NO and NO2 profiles at sunset from analysis of high-resolution balloon-borne infrared solar absorption spectra obtained at 33 deg N and calculations with a time-dependent photochemical model

    NASA Technical Reports Server (NTRS)

    Rinsland, C. P.; Boughner, R. E.; Larsen, J. C.; Goldman, A.; Murcray, F. J.; Murcray, D. G.

    1984-01-01

    Simultaneous stratospheric vertical profiles of NO and NO2 at sunset were derived from an analysis of infrared solar absorption spectra recorded from a float altitude of 33 km with an interferometer system during a balloon flight. A nonlinear least squares procedure was used to analyze the spectral data in regions of absorption by NO and NO2 lines. Normalized factors, determined from calculations of time dependent altitude profiles with a detailed photochemical model, were included in the onion peeling analysis to correct for the rapid diurnal changes in NO and NO2 concentrations with time near sunset. The CO2 profile was also derived from the analysis and is reported.

  16. A new differential absorption lidar to measure sub-hourly fluctuation of tropospheric ozone profiles in the Baltimore-Washington DC region

    NASA Astrophysics Data System (ADS)

    Sullivan, J. T.; McGee, T. J.; Sumnicht, G. K.; Twigg, L. W.; Hoff, R. M.

    2014-04-01

    Tropospheric ozone profiles have been retrieved from the new ground based National Aeronautics and Space Administration (NASA) Goddard Space Flight Center TROPospheric OZone DIfferential Absorption Lidar (GSFC TROPOZ DIAL) in Greenbelt, MD (38.99° N, 76.84° W, 57 m a.s.l.) from 400 m to 12 km a.g.l. Current atmospheric satellite instruments cannot peer through the optically thick stratospheric ozone layer to remotely sense boundary layer tropospheric ozone. In order to monitor this lower ozone more effectively, the Tropospheric Ozone Lidar Network (TOLNet) has been developed, which currently consists of five stations across the US. The GSFC TROPOZ DIAL is based on the Differential Absorption Lidar (DIAL) technique, which currently detects two wavelengths, 289 and 299 nm. Ozone is absorbed more strongly at 289 nm than at 299 nm. The DIAL technique exploits this difference between the returned backscatter signals to obtain the ozone number density as a function of altitude. The transmitted wavelengths are generated by focusing the output of a quadrupled Nd:YAG laser beam (266 nm) into a pair of Raman cells, filled with high pressure hydrogen and deuterium. Stimulated Raman Scattering (SRS) within the focus generates a significant fraction of the pump energy at the first Stokes shift. With the knowledge of the ozone absorption coefficient at these two wavelengths, the range resolved number density can be derived. An interesting atmospheric case study involving the Stratospheric-Tropospheric Exchange (STE) of ozone is shown to emphasize the regional importance of this instrument as well as assessing the validation and calibration of data. The retrieval yields an uncertainty of 16-19% from 0-1.5 km, 10-18% from 1.5-3 km, and 11-25% from 3 km to 12 km. There are currently surface ozone measurements hourly and ozonesonde launches occasionally, but this system will be the first to make routine tropospheric ozone profile measurements in the Baltimore-Washington DC area.

  17. A New Differential Absorption Lidar to Measure Sub-Hourly Fluctuation of Tropospheric Ozone Profiles in the Baltimore - Washington D.C. Region

    NASA Technical Reports Server (NTRS)

    Sullivan, J. T.; McGee, T. J.; Sumnicht, G. K.; Twigg, L. W.; Hoff, R. M.

    2014-01-01

    Tropospheric ozone profiles have been retrieved from the new ground based National Aeronautics and Space Administration (NASA) Goddard Space Flight Center TROPospheric OZone DIfferential Absorption Lidar (GSFC TROPOZ DIAL) in Greenbelt, MD (38.99 N, 76.84 W, 57 meters ASL) from 400 m to 12 km AGL. Current atmospheric satellite instruments cannot peer through the optically thick stratospheric ozone layer to remotely sense boundary layer tropospheric ozone. In order to monitor this lower ozone more effectively, the Tropospheric Ozone Lidar Network (TOLNet) has been developed, which currently consists of five stations across the US. The GSFC TROPOZ DIAL is based on the Differential Absorption Lidar (DIAL) technique, which currently detects two wavelengths, 289 and 299 nm. Ozone is absorbed more strongly at 289 nm than at 299 nm. The DIAL technique exploits this difference between the returned backscatter signals to obtain the ozone number density as a function of altitude. The transmitted wavelengths are generated by focusing the output of a quadrupled Nd:YAG laser beam (266 nm) into a pair of Raman cells, filled with high pressure hydrogen and deuterium. Stimulated Raman Scattering (SRS) within the focus generates a significant fraction of the pump energy at the first Stokes shift. With the knowledge of the ozone absorption coefficient at these two wavelengths, the range resolved number density can be derived. An interesting atmospheric case study involving the Stratospheric-Tropospheric Exchange (STE) of ozone is shown to emphasize the regional importance of this instrument as well as assessing the validation and calibration of data. The retrieval yields an uncertainty of 16-19 percent from 0-1.5 km, 10-18 percent from 1.5-3 km, and 11-25 percent from 3 km to 12 km. There are currently surface ozone measurements hourly and ozonesonde launches occasionally, but this system will be the first to make routine tropospheric ozone profile measurements in the Baltimore

  18. On the computation of a retina resistivity profile for applications in multi-scale modeling of electrical stimulation and absorption

    NASA Astrophysics Data System (ADS)

    Loizos, Kyle; RamRakhyani, Anil Kumar; Anderson, James; Marc, Robert; Lazzi, Gianluca

    2016-06-01

    This study proposes a methodology for computationally estimating resistive properties of tissue in multi-scale computational models, used for studying the interaction of electromagnetic fields with neural tissue, with applications to both dosimetry and neuroprosthetics. Traditionally, models at bulk tissue- and cellular-level scales are solved independently, linking resulting voltage from existing resistive tissue-scale models as extracellular sources to cellular models. This allows for solving the effects that external electric fields have on cellular activity. There are two major limitations to this approach: first, the resistive properties of the tissue need to be chosen, of which there are contradicting measurements in literature; second, the measurements of resistivity themselves may be inaccurate, leading to the mentioned contradicting results found across different studies. Our proposed methodology allows for constructing computed resistivity profiles using knowledge of only the neural morphology within the multi-scale model, resulting in a practical implementation of the effective medium theory; this bypasses concerns regarding the choice of resistive properties and accuracy of measurement setups. A multi-scale model of retina is constructed with an external electrode to serve as a test bench for analyzing existing and resulting resistivity profiles, and validation is presented through the reconstruction of a published resistivity profile of retina tissue. Results include a computed resistivity profile of retina tissue for use with a retina multi-scale model used to analyze effects of external electric fields on neural activity.

  19. On the computation of a retina resistivity profile for applications in multi-scale modeling of electrical stimulation and absorption.

    PubMed

    Loizos, Kyle; RamRakhyani, Anil Kumar; Anderson, James; Marc, Robert; Lazzi, Gianluca

    2016-06-21

    This study proposes a methodology for computationally estimating resistive properties of tissue in multi-scale computational models, used for studying the interaction of electromagnetic fields with neural tissue, with applications to both dosimetry and neuroprosthetics. Traditionally, models at bulk tissue- and cellular-level scales are solved independently, linking resulting voltage from existing resistive tissue-scale models as extracellular sources to cellular models. This allows for solving the effects that external electric fields have on cellular activity. There are two major limitations to this approach: first, the resistive properties of the tissue need to be chosen, of which there are contradicting measurements in literature; second, the measurements of resistivity themselves may be inaccurate, leading to the mentioned contradicting results found across different studies. Our proposed methodology allows for constructing computed resistivity profiles using knowledge of only the neural morphology within the multi-scale model, resulting in a practical implementation of the effective medium theory; this bypasses concerns regarding the choice of resistive properties and accuracy of measurement setups. A multi-scale model of retina is constructed with an external electrode to serve as a test bench for analyzing existing and resulting resistivity profiles, and validation is presented through the reconstruction of a published resistivity profile of retina tissue. Results include a computed resistivity profile of retina tissue for use with a retina multi-scale model used to analyze effects of external electric fields on neural activity. PMID:27223656

  20. On the computation of a retina resistivity profile for applications in multi-scale modeling of electrical stimulation and absorption

    PubMed Central

    Loizos, Kyle; RamRakhyani, Anil Kumar; Anderson, James; Marc, Robert; Lazzi, Gianluca

    2016-01-01

    This study proposes a methodology for computationally estimating resistive properties of tissue in multi-scale computational models, used for studying the interaction of electromagnetic fields with neural tissue, with applications to both dosimetry and neuroprosthetics. Traditionally, models at bulk tissue- and cellular-level scales are solved independently, linking resulting voltage from existing resistive tissue-scale models as extracellular sources to cellular models. This allows for solving the effects that external electric fields have on cellular activity. There are two major limitations to this approach: first, the resistive properties of the tissue need to be chosen, of which there are contradicting measurements in literature; second, the measurements of resistivity themselves may be inaccurate, leading to the mentioned contradicting results found across different studies. Our proposed methodology allows for constructing computed resistivity profiles using knowledge of only the neural morphology within the multi-scale model, resulting in a practical implementation of the effective medium theory; this bypasses concerns regarding the choice of resistive properties and accuracy of measurement setups. A multi-scale model of retina is constructed with an external electrode to serve as a test bench for analyzing existing and resulting resistivity profiles, and validation is presented through the reconstruction of a published resistivity profile of retina tissue. Results include a computed resistivity profile of retina tissue for use with a retina multi-scale model used to analyze effects of external electric fields on neural activity. PMID:27223656

  1. LINKING Lyα AND LOW-IONIZATION TRANSITIONS AT LOW OPTICAL DEPTH

    SciTech Connect

    Jaskot, A. E.; Oey, M. S.

    2014-08-20

    We suggest that low optical depth in the Lyman continuum (LyC) may relate the Lyα emission, C II and Si II absorption, and C II* and Si II* emission seen in high-redshift galaxies. We base this analysis on Hubble Space Telescope Cosmic Origins Spectrograph spectra of four Green Pea (GP) galaxies, which may be analogs of z > 2 Lyα emitters (LAEs). In the two GPs with the strongest Lyα emission, the Lyα line profiles show reduced signs of resonant scattering. Instead, the Lyα profiles resemble the Hα line profiles of evolved star ejecta, suggesting that the Lyα emission originates from a low column density and similar outflow geometry. The weak C II absorption and presence of non-resonant C II* emission in these GPs support this interpretation and imply a low LyC optical depth along the line of sight. In two additional GPs, weak Lyα emission and strong C II absorption suggest a higher optical depth. These two GPs differ in their Lyα profile shapes and C II* emission strengths, however, indicating different inclinations of the outflows to our line of sight. With these four GPs as examples, we explain the observed trends linking Lyα, C II, and C II* in stacked LAE spectra, in the context of optical depth and geometric effects. Specifically, in some galaxies with strong Lyα emission, a low LyC optical depth may allow Lyα to escape with reduced scattering. Furthermore, C II absorption, C II* emission, and Lyα profile shape can reveal the optical depth, constrain the orientation of neutral outflows in LAEs, and identify candidate LyC emitters.

  2. Annealing effects of in-depth profile and band discontinuity in TiN/LaO/HfSiO/SiO{sub 2}/Si gate stack structure studied by angle-resolved photoemission spectroscopy from backside

    SciTech Connect

    Toyoda, S.; Kumigashira, H.; Oshima, M.; Kamada, H.; Tanimura, T.; Ohtsuka, T.; Hata, Y.; Niwa, M.

    2010-01-25

    We have investigated annealing effects on in-depth profile and band discontinuity for a metal gate/high-k gate stack structure on a Si substrate using backside angle-resolved photoemission spectroscopy with synchrotron radiation. In-depth profiles analyzed from angle-resolved photoemission spectroscopy show that La atoms diffuse through the HfSiO layer and reach interfacial SiO{sub 2} layers by rapid thermal annealing. Chemical shift of Si 2p core-level spectra suggests that there are changes in the band discontinuity at the high-k/SiO{sub 2} interface, which is well related to the V{sub th} shift based on the interface dipole model.

  3. Business Week's Guide to the Best Business Schools. Ranking American's Top B-Schools In-Depth Profile of the Best 40 MBA Programs.

    ERIC Educational Resources Information Center

    Byrne, John A., Ed.

    The guide to America's best business schools was based on surveys of students and corporate recruiters as well as interviews with students, recruiters, faculty members, and deans. In addition to the Top 20 schools, it names and profiles 20 other MBA (Master's in Business Administration) schools also judged to be excellent. Profiles of schools…

  4. Helium-3 and boron-10 concentration and depth measurements in alloys and semiconductors using NDP

    NASA Astrophysics Data System (ADS)

    Ünlü, Kenan; Saglam, Mehmet; Wehring, Bernard W.

    1999-02-01

    Neutron Depth Profiling (NDP) is a nondestructive near surface technique that is used to measure concentration versus absolute depth of several isotopes of light mass elements in various substrates. NDP is based on absorption reaction of thermal neutrons with the isotope of interest. Charged particles and recoil atoms are generated in the reaction. The depth profiles are determined by measuring the residual energy of the charged particles or the recoil atoms. The NDP technique has became an increasingly important method to measure depth profiles of 3He and 10B in alloys and semiconductor materials. A permanent NDP facility has been installed on the tangential beam port of the University of Texas (UT) TRIGA Mark-II research reactor. One of the standard applications of the UT-NDP facility involves the determination of boron profiles of borophosphosilicate glass (BPSG) samples. NDP is also being used in combination with electron microscopy measurements to determine radiation damage and microstructural changes in stainless steel samples. This is done to study the long-term effects of high-dose alpha irradiation for weapons grade plutonium encapsulation. Measurements of implanted boron-10 concentration and depth profiles of semiconductor materials in order to calibrate commercial implanters is another application at the UT-NDP facility. The concentration and depth profiles measured with NDP and SIMS are compared with reported data given by various vendors or different implanters in order to verify implant quality of semiconductor wafers. The results of the measurements and other possible applications of NDP are presented.

  5. Grazing-incidence x-ray fluorescence analysis for non-destructive determination of In and Ga depth profiles in Cu(In,Ga)Se{sub 2} absorber films

    SciTech Connect

    Streeck, C.; Brunken, S.; Kaufmann, C. A.; Weber, A.; Schock, H.-W.; Mainz, R.; Gerlach, M.; Hönicke, P.; Lubeck, J.; Pollakowski, B.; Unterumsberger, R.; Beckhoff, B.; Herzog, C.; Kanngießer, B.

    2013-09-09

    Development of highly efficient thin film solar cells involves band gap engineering by tuning their elemental composition with depth. Here we show that grazing incidence X-ray fluorescence (GIXRF) analysis using monochromatic synchrotron radiation and well-characterized instrumentation is suitable for a non-destructive and reference-free analysis of compositional depth profiles in thin films. Variation of the incidence angle provides quantitative access to the in-depth distribution of the elements, which are retrieved from measured fluorescence intensities by modeling parameterized gradients and fitting calculated to measured fluorescence intensities. Our results show that double Ga gradients in Cu(In{sub 1−x},Ga{sub x})Se{sub 2} can be resolved by GIXRF.

  6. Evaluation of Air Pollution Applications of AERONET and MODIS Aerosol Column Optical Depth by Comparison with In Situ Measurements of Aerosol Light Scattering and Absorption for Reno, NV, USA

    NASA Astrophysics Data System (ADS)

    Loria Salazar, S.; Arnott, W. P.; Moosmuller, H.; Colucci, D.

    2012-12-01

    Reno, Nevada, USA is subject to typical urban aerosol, wind-blown dust, and occasional biomass burning smoke from anthropogenic and natural fires. Reno has complex air flow at levels relevant for aerosol transport. At times recirculating mountain and urban flow arrives from the Sierra Nevada, San Francisco, CA and Sacramento, CA. The urban plumes are further modified by biogenic forest emissions and secondary aerosol formation during transport over the Sierra Nevada Mountains to Reno. This complicates the use of MODIS aerosol optical depth (AOD) for air quality measurements in Reno. Our laboratory at the University of Nevada Reno has collocated multispectral photoacoustic instruments and reciprocal nephelometers to measure light absorption and light scattering coefficients as well as an AERONET operated CIMEL CE-318 ground-based sunphotometer. Preliminary measurements from August 2011 indicate substantially larger Cimel AOD than could be accounted for by use of the in situ aerosol extinction measurements combined with mixing height estimate. This poster presents new results comparing AERONET AOD and single scattering albedo and MODIS AOD with in situ measurements for summer and fall 2012, along with extensive back trajectory analysis, to evaluate conditions when satellite measurement may be useful for air pollution applications in Reno.

  7. Depth profile investigation of β-FeSi2 formed in Si(1 0 0) by high fluence implantation of 50 keV Fe ion and post-thermal vacuum annealing

    NASA Astrophysics Data System (ADS)

    Lakshantha, Wickramaarachchige J.; Kummari, Venkata C.; Reinert, Tilo; McDaniel, Floyd D.; Rout, Bibhudutta

    2014-08-01

    A single phase polycrystalline β-FeSi2 layer has been synthesized at the near surface region by implantation in Si(1 0 0) of a high fluence (∼1017 atoms/cm2) of 50 keV Fe ions and subsequent thermal annealing in vacuum at 800 °C. The depth profile of the implanted Fe atoms in Si(1 0 0) were simulated by the widely used transportation of ions in matter (TRIM) computer code as well as by the dynamic transportation of ions in matter code (T-DYN). The simulated depth profile predictions for this heavy ion implantation process were experimentally verified using Rutherford Backscattering Spectrometry (RBS) and X-ray Photoelectron Spectroscopy (XPS) in combination with Ar-ion etching. The formation of the β-FeSi2 phase was monitored by X-ray diffraction measurements. The T-DYN simulations show better agreement with the experimental Fe depth profile results than the static TRIM simulations. The experimental and T-DYN simulated results show an asymmetric distribution of Fe concentrated more toward the surface region of the Si substrate.

  8. Chemical analysis of solid materials by a LIMS instrument designed for space research: 2D elemental imaging, sub-nm depth profiling and molecular surface analysis

    NASA Astrophysics Data System (ADS)

    Moreno-García, Pavel; Grimaudo, Valentine; Riedo, Andreas; Neuland, Maike B.; Tulej, Marek; Broekmann, Peter; Wurz, Peter

    2016-04-01

    Direct quantitative chemical analysis with high lateral and vertical resolution of solid materials is of prime importance for the development of a wide variety of research fields, including e.g., astrobiology, archeology, mineralogy, electronics, among many others. Nowadays, studies carried out by complementary state-of-the-art analytical techniques such as Auger Electron Spectroscopy (AES), X-ray Photoelectron Spectroscopy (XPS), Secondary Ion Mass Spectrometry (SIMS), Glow Discharge Time-of-Flight Mass Spectrometry (GD-TOF-MS) or Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) provide extensive insight into the chemical composition and allow for a deep understanding of processes that might have fashioned the outmost layers of an analyte due to its interaction with the surrounding environment. Nonetheless, these investigations typically employ equipment that is not suitable for implementation on spacecraft, where requirements concerning weight, size and power consumption are very strict. In recent years Laser Ablation/Ionization Mass Spectrometry (LIMS) has re-emerged as a powerful analytical technique suitable not only for laboratory but also for space applications.[1-3] Its improved performance and measurement capabilities result from the use of cutting edge ultra-short femtosecond laser sources, improved vacuum technology and fast electronics. Because of its ultimate compactness, simplicity and robustness it has already proven to be a very suitable analytical tool for elemental and isotope investigations in space research.[4] In this contribution we demonstrate extended capabilities of our LMS instrument by means of three case studies: i) 2D chemical imaging performed on an Allende meteorite sample,[5] ii) depth profiling with unprecedented sub-nm vertical resolution on Cu electrodeposited interconnects[6,7] and iii) preliminary molecular desorption of polymers without assistance of matrix or functionalized substrates.[8] On the whole

  9. The retrieval of atmospheric constituent mixing-ratio profiles from solar absorption spectra. Ph.D. Thesis. Interim Technical Report

    NASA Technical Reports Server (NTRS)

    Shaffer, W. A.

    1983-01-01

    Methods used to determine various atmospheric gas distributions are summarized. The experimentally determined mixi