Science.gov

Sample records for depth profiling techniques

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  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. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  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

    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.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. 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

  13. 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.

  14. 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.}

  15. 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.

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. Flux maximization techniques for compton backscatter depth profilometry.

    PubMed

    Lawson, L

    1993-01-01

    Resolution in x-ray backscatter imaging has often been hampered by low fluxes. But, for a given set of resolution requirements and geometric constraints, it is possible to define a maximization problem in the geometric parameters for which the solution is the maximum flux possible in those circumstances. In this way, resolution in noncritical directions can be traded for improved resolution in a desired direction. Making this the thickness, or surface normal direction, makes practicable the depth profiling of layered structures. Such techniques were applied to the problem of imaging the layered structure of corroding aircraft sheet metal joints using Compton backscatter. PMID:21307450

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. Technique for estimating depths of 100-year floods in Pennsylvania

    USGS Publications Warehouse

    Flippo, Herbert N., Jr.

    1990-01-01

    Techniques are developed for estimating 100-year flood depths in natural channels of unregulated Pennsylvania streams that drain less than 2,200 square miles. Equations and graphs are presented relating the depth of the 100-year flood above median stage and drainage area in five defined hydrologic areas in the State. Another graph defines the relation between drainage area and median depth of flow over the low point of riffles. Thus 100-year depths on riffles can be estimated by summing depth values derived from two simple relations.

  17. 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.

  18. 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.

  19. Technique for estimating depth of 100-year floods in Tennessee

    USGS Publications Warehouse

    Gamble, Charles R.; Lewis, James G.

    1977-01-01

    Preface: A method is presented for estimating the depth of the loo-year flood in four hydrologic areas in Tennessee. Depths at 151 gaging stations on streams that were not significantly affected by man made changes were related to basin characteristics by multiple regression techniques. Equations derived from the analysis can be used to estimate the depth of the loo-year flood if the size of the drainage basin is known.

  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. 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.

  2. 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.

  3. IMPROVED TECHNIQUE FOR ESTIMATING MEAN DEPTHS OF LAKES

    EPA Science Inventory

    The authors describe a technique for determining mean lake depth utilizing a systematically aligned dot grid. This technique is, on the average, 55% faster than the traditional planimeter methods, depending on the type of planimeter and the size and complexity of the lake. No det...

  4. 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.

  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. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Z-depth integration: a new technique for manipulating z-depth properties in composited scenes

    NASA Astrophysics Data System (ADS)

    Steckel, Kayla; Whittinghill, David

    2014-02-01

    This paper presents a new technique in the production pipeline of asset creation for virtual environments called Z-Depth Integration (ZeDI). ZeDI is intended to reduce the time required to place elements at the appropriate z-depth within a scene. Though ZeDI is intended for use primarily in two-dimensional scene composition, depth-dependent "flat" animated objects are often critical elements of augmented and virtual reality applications (AR/VR). ZeDI is derived from "deep image compositing", a capacity implemented within the OpenEXR file format. In order to trick the human eye into perceiving overlapping scene elements as being in front of or behind one another, the developer must manually manipulate which pixels of an element are visible in relation to other objects embedded within the environment's image sequence. ZeDI improves on this process by providing a means for interacting with procedurally extracted z-depth data from a virtual environment scene. By streamlining the process of defining objects' depth characteristics, it is expected that the time and energy required for developers to create compelling AR/VR scenes will be reduced. In the proof of concept presented in this manuscript, ZeDI is implemented for pre-rendered virtual scene construction via an AfterEffects software plug-in.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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

    of the NEXAFS depth profiling technique.

  19. Evaluation of surface decarburization depth by magnetic Barkhausen noise technique

    NASA Astrophysics Data System (ADS)

    Stupakov, O.; Perevertov, O.; Tomáš, I.; Skrbek, B.

    2011-06-01

    Industrially unfavorable process of steel surface decarburization was induced by annealing in air. Two methods of after-anneal surface treatment were used: an acid pickling and a sand blasting. The obtained decarburized layers were examined by optical microscope, wave dispersive spectrometer, and surface X-ray diffraction method. Magnetic Barkhausen noise technique was tested for applicability of non-destructive characterization of the decarburized layer depth. A newly introduced parameter, Barkhausen noise coercivity, was proposed for practical use due to its sensitivity to decarburization and stability to measurement conditions. Other magnetic parameters, e.g. number of Barkhausen noise counts, were found to be sensitive to the compressive residual stress caused by the sand blasting.

  20. 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.

  1. Technique for estimating depth of floods in Tennessee

    USGS Publications Warehouse

    Gamble, C.R.

    1983-01-01

    Estimates of flood depths are needed for design of roadways across flood plains and for other types of construction along streams. Equations for estimating flood depths in Tennessee were derived using data for 150 gaging stations. The equations are based on drainage basin size and can be used to estimate depths of the 10-year and 100-year floods for four hydrologic areas. A method also was developed for estimating depth of floods having recurrence intervals between 10 and 100 years. Standard errors range from 22 to 30 percent for the 10-year depth equations and from 23 to 30 percent for the 100-year depth equations. (USGS)

  2. 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.

  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. 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. 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.

  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. 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

  8. Compressive and Shear Wave Velocity Profiles using Seismic Refraction Technique

    NASA Astrophysics Data System (ADS)

    Aziman, M.; Hazreek, Z. A. M.; Azhar, A. T. S.; Haimi, D. S.

    2016-04-01

    Seismic refraction measurement is one of the geophysics exploration techniques to determine soil profile. Meanwhile, the borehole technique is an established way to identify the changes of soil layer based on number of blows penetrating the soil. Both techniques are commonly adopted for subsurface investigation. The seismic refraction test is a non-destructive and relatively fast assessment compared to borehole technique. The soil velocities of compressive wave and shear wave derived from the seismic refraction measurements can be directly utilised to calculate soil parameters such as soil modulus and Poisson’s ratio. This study investigates the seismic refraction techniques to obtain compressive and shear wave velocity profile. Using the vertical and horizontal geophones as well as vertical and horizontal strike directions of the transient seismic source, the propagation of compressive wave and shear wave can be examined, respectively. The study was conducted at Sejagung Sri Medan. The seismic velocity profile was obtained at a depth of 20 m. The velocity of the shear wave is about half of the velocity of the compression wave. The soil profiles of compressive and shear wave velocities were verified using the borehole data and showed good agreement with the borehole data.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. 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

  14. Classification of wheat: Badhwar profile similarity technique

    NASA Technical Reports Server (NTRS)

    Austin, W. W.

    1980-01-01

    The Badwar profile similarity classification technique used successfully for classification of corn was applied to spring wheat classifications. The software programs and the procedures used to generate full-scene classifications are presented, and numerical results of the acreage estimations are given.

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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).

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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…

  5. 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.

  6. 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

  7. 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

  8. Sounding depth measurements: a method for evaluating various surgical techniques.

    PubMed

    Ben-Yehouda, A; Machtei, E E

    1991-09-01

    Fourteen patients undergoing periodontal treatment for moderate to severe adult-type periodontitis were included in the study. Seven patients (a total of 210 sites) were treated with modified Widman flap surgery while the other 7 patients (the same number of sites) were treated with apically-positioned flap surgery. The 2 modalities were compared using sounding depth measurements before and immediately after surgery. The mean sounding depth decreased from 4.89 mm to 3.42 mm in the modified Widman flap group, compared to a drop from 4.77 mm to 2.46 mm in the apically-positioned flap group. Neither of these procedures resulted in the total eradication of all periodontal pockets. The final outcome of modified Widman flap surgery may, at times, result in zero sounding depth (placement of the flap at the crest of the bone); on the other hand, very often the flap was placed far supra-crestally in an intended apically-positioned flap procedure. This lack of consistency between intended and actual flap placement would suggest that studies which try to compare different treatment modalities using a flap approach should include sounding depth measurements immediately post-surgery. This is needed to assure that the intended procedure has actually been carried out. PMID:1941496

  9. 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.

  10. 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.

  11. 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

  12. 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

  13. 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

  14. SU-E-T-561: Development of Depth Dose Measurement Technique Using the Multilayer Ionization Chamber for Spot Scanning Method

    SciTech Connect

    Takayanagi, T; Fujitaka, S; Umezawa, M; Ito, Y; Nakashima, C; Matsuda, K

    2014-06-01

    Purpose: To develop a measurement technique which suppresses the difference between profiles obtained with a multilayer ionization chamber (MLIC) and with a water phantom. Methods: The developed technique multiplies the raw MLIC data by a correction factor that depends on the initial beam range and water equivalent depth. The correction factor is derived based on a Bragg curve calculation formula considering range straggling and fluence loss caused by nuclear reactions. Furthermore, the correction factor is adjusted based on several integrated depth doses measured with a water phantom and the MLIC. The measured depth dose profiles along the central axis of the proton field with a nominal field size of 10 by 10 cm were compared between the MLIC using the new technique and the water phantom. The spread out Bragg peak was 20 cm for fields with a range of 30.6 cm and 6.9 cm. Raw MLIC data were obtained with each energy layer, and integrated after multiplying by the correction factor. The measurements were performed by a spot scanning nozzle at Nagoya Proton Therapy Center, Japan. Results: The profile measured with the MLIC using the new technique is consistent with that of the water phantom. Moreover, 97% of the points passed the 1% dose /1mm distance agreement criterion of the gamma index. Conclusion: We have demonstrated that the new technique suppresses the difference between profiles obtained with the MLIC and with the water phantom. It was concluded that this technique is useful for depth dose measurement in proton spot scanning method.

  15. 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.

  16. 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

  17. Interpretation and Evaluation of Stylus Profiling Techniques

    NASA Astrophysics Data System (ADS)

    Li, Man

    1991-01-01

    Available from UMI in association with The British Library. Requires signed TDF. The object of this Ph.D work is to validate stylus profiling techniques for ultra-high precision measurement and positioning in engineering. Stylus methods have been used extensively and successfully in the past in the fields of manufacturing control and components function study, but some problems still exist. Now their role has considerably expanded with the appearance of scanning probe microscopes and the new emphasis on nanotechnology, which shortens the gap between engineering and physics. The profiling technique is interpreted and evaluated in terms of the mechanical aspects of data collection through a stylus surface instrument. This work contains: (a) 3D digital sampling techniques; (b) effects of the finite dimension of stylus and (c) forces contributing to measurement. A new plane sampling model--hexagonal model--has been developed to improve the surface 3D data collection to almost 99% of the continuous case for summit height distribution. The dimension effect has been divided into two aspects: the effects of size and the shape. The cut -off effect caused by the size of the stylus on the surface curvature is not correctable. The analysis of the trace formation suggests that the 'deconvolution' of the true profile from the trace is feasible. The simulation using the MAT-LAB computer package confirms this with only computational error. A new method of stylus shape/dimension measurement was proposed based on these principles. Alternatively, a practical method of measuring a stylus shape using a knife-edge was also constructed and further developed. Stylii tips of radii from 1 μm to 50 μm can be measured using this rig to an accuracy of only 5% of the movement of the knife-edge. The physical effect of a stylus is discussed theoretically and experimentally in terms of the static and dynamic stylus loading forces. The dynamic variation is only 2.7% of the static one and it is

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. 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.

  3. 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

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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

  12. 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

  13. 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.

  14. 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

  15. 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.

  16. Target deconvolution techniques in modern phenotypic profiling

    PubMed Central

    Lee, Jiyoun; Bogyo, Matthew

    2013-01-01

    The past decade has seen rapid growth in the use of diverse compound libraries in classical phenotypic screens to identify modulators of a given process. The subsequent process of identifying the molecular targets of active hits, also called ‘target deconvolution’, is an essential step for understanding compound mechanism of action and for using the identified hits as tools for further dissection of a given biological process. Recent advances in ‘omics’ technologies, coupled with in silico approaches and the reduced cost of whole genome sequencing, have greatly improved the workflow of target deconvolution and have contributed to a renaissance of ‘modern’ phenotypic profiling. In this review, we will outline how both new and old techniques are being used in the difficult process of target identification and validation as well as discuss some of the ongoing challenges remaining for phenotypic screening. PMID:23337810

  17. 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

  18. 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

  19. 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

  20. 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.

  1. 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

  2. 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.

  3. 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

  4. Correction techniques for depth errors with stereo three-dimensional graphic displays

    NASA Technical Reports Server (NTRS)

    Parrish, Russell V.; Holden, Anthony; Williams, Steven P.

    1992-01-01

    Three-dimensional (3-D), 'real-world' pictorial displays that incorporate 'true' depth cues via stereopsis techniques have proved effective for displaying complex information in a natural way to enhance situational awareness and to improve pilot/vehicle performance. In such displays, the display designer must map the depths in the real world to the depths available with the stereo display system. However, empirical data have shown that the human subject does not perceive the information at exactly the depth at which it is mathematically placed. Head movements can also seriously distort the depth information that is embedded in stereo 3-D displays because the transformations used in mapping the visual scene to the depth-viewing volume (DVV) depend intrinsically on the viewer location. The goal of this research was to provide two correction techniques; the first technique corrects the original visual scene to the DVV mapping based on human perception errors, and the second (which is based on head-positioning sensor input data) corrects for errors induced by head movements. Empirical data are presented to validate both correction techniques. A combination of the two correction techniques effectively eliminates the distortions of depth information embedded in stereo 3-D displays.

  5. 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.

  6. A technique using a stellar spectrographic plate to measure terrestrial ozone column depth

    SciTech Connect

    Wong, A.Y.

    1995-08-01

    This thesis examines the feasibility of a technique to extract ozone column depths from photographic stellar spectra in the 5000--7000 Angstrom spectral region. A stellar spectrographic plate is measured to yield the relative intensity distribution of a star`s radiation after transmission through the earth`s atmosphere. The amount of stellar radiation absorbed by the ozone Chappuis band is proportional to the ozone column depth. The measured column depth is within 10% the mean monthly value for latitude 36{degree}N, however the uncertainty is too large to make the measurement useful. This thesis shows that a 10% improvement to the photographic sensitivity uncertainty can decrease the column depth uncertainty to a level acceptable for climatic study use. This technique offers the possibility of measuring past ozone column depths.

  7. 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

  8. 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.

  9. 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.

  10. 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.

  11. Effect of hold depth and grip technique on maximal finger forces in rock climbing.

    PubMed

    Amca, Arif Mithat; Vigouroux, Laurent; Aritan, Serdar; Berton, Eric

    2012-01-01

    The aim of this study was to understand how the commonly used climbing-specific grip techniques and hold depths influence the finger force capacities. Ten advanced climbers performed maximal voluntary force on four different hold depths (from 1 to 4 cm) and in two force directions (antero-posterior and vertical) using three grip techniques (slope, half crimp and full crimp). A specially designed platform instrumented with a 6-degrees-of-freedom (DoF) force/torque sensor was used to record force values. Results showed that the maximal vertical forces differed significantly according to the hold depth and the grip technique (ranged from 350.8 N to 575.7 N). The maximal vertical forces increased according to the hold depth but the form of this increase differed depending on grip technique. These results seemed to be more associated with finger-hold contact/interaction than with internal biomechanical factors. Similar results were revealed for antero-posterior forces (ranged from 69.9 N to 138.0 N) but, it was additionally noted that climbers have different hand-forearm posture strategies with slope and crimp grip techniques when applying antero-posterior forces. This point is important as it could influence the body position adopted during climbing according to the chosen grip technique. For trainers and designers, a polynomial regression model was proposed in order to predict the mean maximal force based on hold depth and adopted grip technique. PMID:22339482

  12. 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.

  13. 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.

  14. 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

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. {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.

  8. A Systematic Review of the Evolution of Laser Doppler Techniques in Burn Depth Assessment

    PubMed Central

    Fitzgerald O'Connor, Edmund; Philp, Bruce

    2014-01-01

    Aims. The introduction of laser Doppler (LD) techniques to assess burn depth has revolutionized the treatment of burns of indeterminate depth. This paper will systematically review studies related to these two techniques and trace their evolution. At the same time we hope to highlight current controversies and areas where further research is necessary with regard to LD imaging (LDI) techniques. Methods. A systematic search for relevant literature was carried out on PubMed, Medline, EMBASE, and Google Scholar. Key search terms included the following: “Laser Doppler imaging,” “laser Doppler flow,” and “burn depth.” Results. A total of 53 studies were identified. Twenty-six studies which met the inclusion/exclusion criteria were included in the review. Conclusions. The numerous advantages of LDI over those of LD flowmetry have resulted in the former technique superseding the latter one. Despite the presence of alternative burn depth assessment techniques, LDI remains the most favoured. Various newer LDI machines with increasingly sophisticated methods of assessing burn depth have been introduced throughout the years. However, factors such as cost effectiveness, scanning of topographically inconsistent areas of the body, and skewing of results due to tattoos, peripheral vascular disease, and anaemia continue to be sighted as obstacles to LDI which require further research. PMID:25180087

  9. Thermoreflectance-based in-depth stress distribution measurement technique for single-crystal silicon structures

    NASA Astrophysics Data System (ADS)

    Miyake, Shugo; Kato, Takaaki; Taguchi, Hideyuki; Namazu, Takahiro

    2016-06-01

    In this paper, we suggest a new stress measurement technique based on the thermoreflectance method for the estimation of the in-depth stress distribution of fabricated silicon devices. Changing the modulated intensity of a heating laser beam of the frequency-domain thermoreflectance method (FD-TRM) can vary the estimation depth optionally. We developed a measurement system on the basis of the FD-TRM and demonstrated in-depth stress measurement for a single-crystal silicon (SCS) sample. The result measured at a modulation frequency of 3 MHz showed the phase distribution of the TR signal corresponding to the stress distribution determined by 632-nm-excited Raman spectroscopy. In addition, it was found that the phase distribution changed depending on the modulation frequency. The FD-TRM can be a powerful technique for estimating the in-depth stress distribution of silicon materials.

  10. 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

  11. 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.

  12. 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.

  13. 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

  14. 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

  15. 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.

  16. 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.

  17. Uncertainty quantification of three-dimensional velocimetry techniques for small measurement depths

    NASA Astrophysics Data System (ADS)

    Fuchs, Thomas; Hain, Rainer; Kähler, Christian J.

    2016-05-01

    In this paper, the multi-camera techniques tomographic PTV and 3D-PTV as well as the single-camera defocusing PTV approach are assessed for flow measurements with a small measurement depth in conjunction with a high resolution along the optical axis. This includes the measurement of flows with strong velocity gradients in z direction and flow features, which have smaller scales than the actual light sheet thickness. Furthermore, in fields like turbomachinery, the measurement of flows in domains with small depth dimensions is of great interest. Typically, these domains have dimensions on the order of 100 mm in z direction and of 101 mm in x and y direction. For small domain depths, employing a 3D flow velocimetry technique is inevitable, since the measurement depths lie in the range of the light sheet thickness. To resolve strong velocity gradients and small-scale flow features along the z axis, the accuracy and spatial resolution of the 3D technique are very important. For the comparison of the different measurement methods, a planar Poiseuille flow is investigated. Quantitative uncertainty analyses reveal the excellent suitability of all three methods for the measurement of flows in domains with small measurement depths. Naturally, the multi-camera approaches tomographic PTV and 3D-PTV yield lower uncertainties, since they image the measurement volume from different angles. Other criteria, such as optical access requirements, hardware costs, and setup complexity, clearly favor defocusing PTV over the more complex multi-camera techniques.

  18. 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

  19. 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

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. 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

  6. 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

  7. 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.

  8. 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

  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. 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

  11. Design of Optical Systems with Extended Depth of Field: An Educational Approach to Wavefront Coding Techniques

    ERIC Educational Resources Information Center

    Ferran, C.; Bosch, S.; Carnicer, A.

    2012-01-01

    A practical activity designed to introduce wavefront coding techniques as a method to extend the depth of field in optical systems is presented. The activity is suitable for advanced undergraduate students since it combines different topics in optical engineering such as optical system design, aberration theory, Fourier optics, and digital image…

  12. 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.

  13. 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

  14. 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

  15. 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.

  16. 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.

  17. 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

  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. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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

  5. A technique for determining depths for T-year discharges in rigid-boundary channels

    USGS Publications Warehouse

    Burkham, D.E.

    1977-01-01

    A simplified technique is presented for determining depths for T-year discharges (the discharge that will occur, on an average, once in T-years--10 years, 50 years, 100 years) for natural channels (channels not significantly affected by manmade structures) having channel-control conditions and rigid boundaries (channels having a low probability of change that would significantly affect the hydraulic characteristics of a T-year discharge). Channel-control conditions usually exist during T-year discharges in natural rigid-boundary channels and, therefore, the simplified technique probably would be applicable for flood-inundation studies for many natural rigid-boundary channels. The technique requires that the T-year discharge for a reach be known or readily available; also, a channel-shape factor, a width at a reference altitude, a channel-bottom slope (or a water-surface slope), and the Manning 's roughness factor, n, must be estimated or determined at representative sections having channel-control conditions. The standard error of estimate for depths determined according to the simplified technique is probably 25-30 percent. In comparison, the standard error of estimate for the depths determined according to the step-backwater procedure and to guidelines and specifications for flood-insurance studies of the Federal Insurance Administration is about 23 percent. (Woodard-USGS)

  6. 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

  7. 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

  8. 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).

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  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. 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.

  15. 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

  16. 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.

  17. 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

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 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

  9. 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

  10. 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.

  11. New radiosonde techniques to measure radiation profiles through the atmosphere

    NASA Astrophysics Data System (ADS)

    Kräuchi, Andreas; Philipona, Rolf; Romanens, Gonzague; Levrat, Gilbert

    2013-04-01

    Solar and thermal radiation fluxes are usually measured at Earth's surface and at the top of the atmosphere. Here we show radiosonde techniques that allow measuring radiation flux profiles and the radiation budget from the Earth's surface to above 30 km in the stratosphere. During two-hour flights solar shortwave and thermal longwave irradiance, downward and upward, is measured with four individual sensors at one-second resolution, along with standard PTU radiosonde profiles. Daytime and nighttime shortwave and longwave radiation measurements, and 24 hours surface measurements, allow determining radiation budget- and total net radiation profiles through the atmosphere. We use a double balloon technique to prevent pendulum motion during the ascent and to keep the sonde as horizontal as possible. New techniques using auto controlled airplanes are now investigated to retrieve the sonde after release at a certain altitude and to land it if possible at the launch station.

  12. 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

  13. 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.

  14. 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

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. 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

  3. 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

  4. Soil temperature modeling at different depths using neuro-fuzzy, neural network, and genetic programming techniques

    NASA Astrophysics Data System (ADS)

    Kisi, Ozgur; Sanikhani, Hadi; Cobaner, Murat

    2016-05-01

    The applicability of artificial neural networks (ANN), adaptive neuro-fuzzy inference system (ANFIS), and genetic programming (GP) techniques in estimating soil temperatures (ST) at different depths is investigated in this study. Weather data from two stations, Mersin and Adana, Turkey, were used as inputs to the applied models in order to model monthly STs. The first part of the study focused on comparison of ANN, ANFIS, and GP models in modeling ST of two stations at the depths of 10, 50, and 100 cm. GP was found to perform better than the ANN and ANFIS-SC in estimating monthly ST. The effect of periodicity (month of the year) on models' accuracy was also investigated. Including periodicity component in models' inputs considerably increased their accuracies. The root mean square error (RMSE) of ANN models was respectively decreased by 34 and 27 % for the depths of 10 and 100 cm adding the periodicity input. In the second part of the study, the accuracies of the ANN, ANFIS, and GP models were compared in estimating ST of Mersin Station using the climatic data of Adana Station. The ANN models generally performed better than the ANFIS-SC and GP in modeling ST of Mersin Station without local climatic inputs.

  5. 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.

  6. 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

  7. 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

  8. 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.

  9. 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.

  10. 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.