Science.gov

Sample records for high-resolution angle-resolved measurements

  1. Nodal Quasiparticle Meltdown in Ultra-High Resolution Pump-Probe Angle-Resolved Photoemission

    SciTech Connect

    Graf, Jeff; Jozwiak, Chris; Smallwood, Chris L.; Eisaki, H.; Kaindl, Robert A.; Lee, Dung-Hai; Lanzara, Alessandra

    2011-06-03

    High-T{sub c} cuprate superconductors are characterized by a strong momentum-dependent anisotropy between the low energy excitations along the Brillouin zone diagonal (nodal direction) and those along the Brillouin zone face (antinodal direction). Most obvious is the d-wave superconducting gap, with the largest magnitude found in the antinodal direction and no gap in the nodal direction. Additionally, while antin- odal quasiparticle excitations appear only below T{sub c}, superconductivity is thought to be indifferent to nodal excitations as they are regarded robust and insensitive to T{sub c}. Here we reveal an unexpected tie between nodal quasiparticles and superconductivity using high resolution time- and angle-resolved photoemission on optimally doped Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+{delta}} . We observe a suppression of the nodal quasiparticle spectral weight following pump laser excitation and measure its recovery dynamics. This suppression is dramatically enhanced in the superconducting state. These results reduce the nodal-antinodal dichotomy and challenge the conventional view of nodal excitation neutrality in superconductivity. The electronic structures of high-Tc cuprates are strongly momentum-dependent. This is one reason why the momentum-resolved technique of angle-resolved photoemission spectroscopy (ARPES) has been a central tool in the field of high-temperature superconductivity. For example, coherent low energy excitations with momenta near the Brillouin zone face, or antinodal quasiparticles (QPs), are only observed below T{sub c} and have been linked to superfluid density. They have therefore been the primary focus of ARPES studies. In contrast, nodal QPs, with momenta along the Brillouin zone diagonal, have received less attention and are usually regarded as largely immune to the superconducting transition because they seem insensitive to perturbations such as disorder, doping, isotope exchange, charge ordering, and temperature. Clearly

  2. High Resolution Angle Resolved Photoemission Studies on Quasi-Particle Dynamics in Graphite

    SciTech Connect

    Leem, C.S.

    2010-06-02

    We obtained the spectral function of the graphite H point using high resolution angle resolved photoelectron spectroscopy (ARPES). The extracted width of the spectral function (inverse of the photo-hole lifetime) near the H point is approximately proportional to the energy as expected from the linearly increasing density of states (DOS) near the Fermi energy. This is well accounted by our electron-phonon coupling theory considering the peculiar electronic DOS near the Fermi level. And we also investigated the temperature dependence of the peak widths both experimentally and theoretically. The upper bound for the electron-phonon coupling parameter is 0.23, nearly the same value as previously reported at the K point. Our analysis of temperature dependent ARPES data at K shows that the energy of phonon mode of graphite has much higher energy scale than 125K which is dominant in electron-phonon coupling.

  3. A tunable low-energy photon source for high-resolution angle-resolved photoemission spectroscopy

    SciTech Connect

    Harter, John W.; Monkman, Eric J.; Shai, Daniel E.; Nie Yuefeng; Uchida, Masaki; Burganov, Bulat; Chatterjee, Shouvik; King, Philip D. C.; Shen, Kyle M.

    2012-11-15

    We describe a tunable low-energy photon source consisting of a laser-driven xenon plasma lamp coupled to a Czerny-Turner monochromator. The combined tunability, brightness, and narrow spectral bandwidth make this light source useful in laboratory-based high-resolution photoemission spectroscopy experiments. The source supplies photons with energies up to {approx}7 eV, delivering under typical conditions >10{sup 12} ph/s within a 10 meV spectral bandwidth, which is comparable to helium plasma lamps and many synchrotron beamlines. We first describe the lamp and monochromator system and then characterize its output, with attention to those parameters which are of interest for photoemission experiments. Finally, we present angle-resolved photoemission spectroscopy data using the light source and compare its performance to a conventional helium plasma lamp.

  4. Invited Article: High resolution angle resolved photoemission with tabletop 11 eV laser

    NASA Astrophysics Data System (ADS)

    He, Yu; Vishik, Inna M.; Yi, Ming; Yang, Shuolong; Liu, Zhongkai; Lee, James J.; Chen, Sudi; Rebec, Slavko N.; Leuenberger, Dominik; Zong, Alfred; Jefferson, C. Michael; Moore, Robert G.; Kirchmann, Patrick S.; Merriam, Andrew J.; Shen, Zhi-Xun

    2016-01-01

    We developed a table-top vacuum ultraviolet (VUV) laser with 113.778 nm wavelength (10.897 eV) and demonstrated its viability as a photon source for high resolution angle-resolved photoemission spectroscopy (ARPES). This sub-nanosecond pulsed VUV laser operates at a repetition rate of 10 MHz, provides a flux of 2 × 1012 photons/s, and enables photoemission with energy and momentum resolutions better than 2 meV and 0.012 Å-1, respectively. Space-charge induced energy shifts and spectral broadenings can be reduced below 2 meV. The setup reaches electron momenta up to 1.2 Å-1, granting full access to the first Brillouin zone of most materials. Control over the linear polarization, repetition rate, and photon flux of the VUV source facilitates ARPES investigations of a broad range of quantum materials, bridging the application gap between contemporary low energy laser-based ARPES and synchrotron-based ARPES. We describe the principles and operational characteristics of this source and showcase its performance for rare earth metal tritellurides, high temperature cuprate superconductors, and iron-based superconductors.

  5. Invited Article: High resolution angle resolved photoemission with tabletop 11 eV laser.

    PubMed

    He, Yu; Vishik, Inna M; Yi, Ming; Yang, Shuolong; Liu, Zhongkai; Lee, James J; Chen, Sudi; Rebec, Slavko N; Leuenberger, Dominik; Zong, Alfred; Jefferson, C Michael; Moore, Robert G; Kirchmann, Patrick S; Merriam, Andrew J; Shen, Zhi-Xun

    2016-01-01

    We developed a table-top vacuum ultraviolet (VUV) laser with 113.778 nm wavelength (10.897 eV) and demonstrated its viability as a photon source for high resolution angle-resolved photoemission spectroscopy (ARPES). This sub-nanosecond pulsed VUV laser operates at a repetition rate of 10 MHz, provides a flux of 2 × 10(12) photons/s, and enables photoemission with energy and momentum resolutions better than 2 meV and 0.012 Å(-1), respectively. Space-charge induced energy shifts and spectral broadenings can be reduced below 2 meV. The setup reaches electron momenta up to 1.2 Å(-1), granting full access to the first Brillouin zone of most materials. Control over the linear polarization, repetition rate, and photon flux of the VUV source facilitates ARPES investigations of a broad range of quantum materials, bridging the application gap between contemporary low energy laser-based ARPES and synchrotron-based ARPES. We describe the principles and operational characteristics of this source and showcase its performance for rare earth metal tritellurides, high temperature cuprate superconductors, and iron-based superconductors. PMID:26827301

  6. Design of a High Resolution and High Flux Beam line for VUV Angle-Resolved Photoemission at UVSOR-II

    SciTech Connect

    Kimura, Shin-ichi; Ito, Takahiro; Nakamura, Eiken; Hosaka, Masahito; Katoh, Masahiro

    2007-01-19

    A high-energy-resolution angle-resolved photoemission beamline in the vacuum-ultraviolet (VUV) region has been designed for a 750 MeV synchrotron light source UVSOR-II. The beamline equips an APPLE-II-type undulator with the horizontally/vertically linear and right/left circular polarizations, a modified Wadsworth-type monochromator and a high-resolution photoelectron analyzer. The monochromator covers the photon energy range of 6 - 40 eV. The energy resolution (hv/{delta}hv) and the photon flux on samples are expected to be 2 x 104 and 1012 photons/sec at 10 eV, 4 x 104 and 5 x 1011 photons/sec at 20 eV, and 6 x 104 and 1011 photons/sec at 40 eV, respectively. The beamline provides the high-resolution angle-resolved photoemission spectroscopy less than 1 meV in the whole VUV energy range.

  7. Rapid high-resolution spin- and angle-resolved photoemission spectroscopy with pulsed laser source and time-of-flight spectrometer

    SciTech Connect

    Gotlieb, K.; Hussain, Z.; Bostwick, A.; Jozwiak, C.; Lanzara, A.

    2013-09-15

    A high-efficiency spin- and angle-resolved photoemission spectroscopy (spin-ARPES) spectrometer is coupled with a laboratory-based laser for rapid high-resolution measurements. The spectrometer combines time-of-flight (TOF) energy measurements with low-energy exchange scattering spin polarimetry for high detection efficiencies. Samples are irradiated with fourth harmonic photons generated from a cavity-dumped Ti:sapphire laser that provides high photon flux in a narrow bandwidth, with a pulse timing structure ideally matched to the needs of the TOF spectrometer. The overall efficiency of the combined system results in near-E{sub F} spin-resolved ARPES measurements with an unprecedented combination of energy resolution and acquisition speed. This allows high-resolution spin measurements with a large number of data points spanning multiple dimensions of interest (energy, momentum, photon polarization, etc.) and thus enables experiments not otherwise possible. The system is demonstrated with spin-resolved energy and momentum mapping of the L-gap Au(111) surface states, a prototypical Rashba system. The successful integration of the spectrometer with the pulsed laser system demonstrates its potential for simultaneous spin- and time-resolved ARPES with pump-probe based measurements.

  8. Coupling parameters of many-body interactions for the Al(100) surface state: A high-resolution angle-resolved photoemission spectroscopy study

    NASA Astrophysics Data System (ADS)

    Jiang, J.; Shimada, K.; Hayashi, H.; Iwasawa, H.; Aiura, Y.; Namatame, H.; Taniguchi, M.

    2011-10-01

    We examined the dimensionless coupling parameters of many-body interactions for a free-electron-like surface-derived state in Al(100) by means of high-resolution angle-resolved photoemission spectroscopy. A kink structure was found to exist in the energy-band dispersion near the Fermi level (EF), which was attributed to the electron-phonon interaction. At 50 K, the coupling parameters of the electron-phonon and electron-electron interactions were estimated as λep=0.67±0.05 and λee˜0.003, respectively, indicating that the effective mass enhancement was mainly derived from the electron-phonon interaction. The temperature dependence of the kink structure, as measured by λep(T), was consistent with a theoretical calculation based on the Eliashberg function. A quasiparticle peak with a width of 15-20 meV was found near EF, which was explained well by the simulated spectral function incorporating the self-energy evaluated in this study. We found that the electrons at the surface were strongly scattered by the defects at the surface and that the linewidth was significantly broadened (Γ0=0.238±0.006 eV).

  9. High-resolution three-dimensional spin- and angle-resolved photoelectron spectrometer using vacuum ultraviolet laser light

    NASA Astrophysics Data System (ADS)

    Yaji, Koichiro; Harasawa, Ayumi; Kuroda, Kenta; Toyohisa, Sogen; Nakayama, Mitsuhiro; Ishida, Yukiaki; Fukushima, Akiko; Watanabe, Shuntaro; Chen, Chuangtian; Komori, Fumio; Shin, Shik

    2016-05-01

    We describe a spin- and angle-resolved photoelectron spectroscopy (SARPES) apparatus with a vacuum-ultraviolet (VUV) laser (hν = 6.994 eV) developed at the Laser and Synchrotron Research Center at the Institute for Solid State Physics, The University of Tokyo. The spectrometer consists of a hemispherical photoelectron analyzer equipped with an electron deflector function and twin very-low-energy-electron-diffraction-type spin detectors, which allows us to analyze the spin vector of a photoelectron three-dimensionally with both high energy and angular resolutions. The combination of the high-performance spectrometer and the high-photon-flux VUV laser can achieve an energy resolution of 1.7 meV for SARPES. We demonstrate that the present laser-SARPES machine realizes a quick SARPES on the spin-split band structure of a Bi(111) film even with 7 meV energy and 0.7∘ angular resolutions along the entrance-slit direction. This laser-SARPES machine is applicable to the investigation of spin-dependent electronic states on an energy scale of a few meV.

  10. High-resolution three-dimensional spin- and angle-resolved photoelectron spectrometer using vacuum ultraviolet laser light.

    PubMed

    Yaji, Koichiro; Harasawa, Ayumi; Kuroda, Kenta; Toyohisa, Sogen; Nakayama, Mitsuhiro; Ishida, Yukiaki; Fukushima, Akiko; Watanabe, Shuntaro; Chen, Chuangtian; Komori, Fumio; Shin, Shik

    2016-05-01

    We describe a spin- and angle-resolved photoelectron spectroscopy (SARPES) apparatus with a vacuum-ultraviolet (VUV) laser (hν = 6.994 eV) developed at the Laser and Synchrotron Research Center at the Institute for Solid State Physics, The University of Tokyo. The spectrometer consists of a hemispherical photoelectron analyzer equipped with an electron deflector function and twin very-low-energy-electron-diffraction-type spin detectors, which allows us to analyze the spin vector of a photoelectron three-dimensionally with both high energy and angular resolutions. The combination of the high-performance spectrometer and the high-photon-flux VUV laser can achieve an energy resolution of 1.7 meV for SARPES. We demonstrate that the present laser-SARPES machine realizes a quick SARPES on the spin-split band structure of a Bi(111) film even with 7 meV energy and 0.7(∘) angular resolutions along the entrance-slit direction. This laser-SARPES machine is applicable to the investigation of spin-dependent electronic states on an energy scale of a few meV. PMID:27250396

  11. High resolution infrared measurements

    NASA Technical Reports Server (NTRS)

    Kessler, B.; Cawley, Robert

    1990-01-01

    Sample ground based cloud radiance data from a high resolution infrared sensor are shown and the sensor characteristics are presented in detail. The purpose of the Infrared Analysis Measurement and Modeling Program (IRAMMP) is to establish a deterministic radiometric data base of cloud, sea, and littoral terrain clutter to be used to advance the design and development of Infrared Search and Track (IRST) systems as well as other infrared devices. The sensor is a dual band radiometric sensor and its description, together with that of the Data Acquisition System (DAS), are given. A schematic diagram of the sensor optics is shown.

  12. An ultrafast angle-resolved photoemission apparatus for measuring complex materials.

    PubMed

    Smallwood, Christopher L; Jozwiak, Christopher; Zhang, Wentao; Lanzara, Alessandra

    2012-12-01

    We present technical specifications for a high resolution time- and angle-resolved photoemission spectroscopy setup based on a hemispherical electron analyzer and cavity-dumped solid state Ti:sapphire laser used to generate pump and probe beams, respectively, at 1.48 and 5.93 eV. The pulse repetition rate can be tuned from 209 Hz to 54.3 MHz. Under typical operating settings the system has an overall energy resolution of 23 meV, an overall momentum resolution of 0.003 Å(-1), and an overall time resolution of 310 fs. We illustrate the system capabilities with representative data on the cuprate superconductor Bi(2)Sr(2)CaCu(2)O(8+δ). The descriptions and analyses presented here will inform new developments in ultrafast electron spectroscopy. PMID:23278002

  13. Measurement of angle-resolved scattering property of ovarian tissue by use of OCT

    NASA Astrophysics Data System (ADS)

    Yang, Yi; Wang, Tianheng; Brewer, Molly; Zhu, Quing

    2013-03-01

    Angle-resolved optical scattering properties of ovarian tissue on different optical coherence tomography (OCT) imaging planes were quantitatively measured by fitting the compounded OCT A-lines into a single scattering model. Higher cross correlation value of angle-resolved scattering coefficients between different OCT imaging planes was found in normal ovaries than was present in malignant ovaries. The mean cross correlation coefficient (MCC) was introduced in this pilot study to characterize and differentiate normal and malignant ovaries. A specificity of 100% and a sensitivity of 100% were achieved by setting MCC threshold at 0.6 in the limited sample population. The collagen properties such as content, structure and directivity were found to be different within OCT imaging penetration depth between normal and malignant ovarian tissue. The homogeneous three-dimensional collagen fiber network observed in the normal ovary effectively explains the stronger cross correlation of angle-resolved scattering properties on different imaging planes while the heterogeneity observed in the malignant ovary suggests a weaker correlation.

  14. High-resolution soft X-ray beamline ADRESS at the Swiss Light Source for resonant inelastic X-ray scattering and angle-resolved photoelectron spectroscopies.

    PubMed

    Strocov, V N; Schmitt, T; Flechsig, U; Schmidt, T; Imhof, A; Chen, Q; Raabe, J; Betemps, R; Zimoch, D; Krempasky, J; Wang, X; Grioni, M; Piazzalunga, A; Patthey, L

    2010-09-01

    The concepts and technical realisation of the high-resolution soft X-ray beamline ADRESS operating in the energy range from 300 to 1600 eV and intended for resonant inelastic X-ray scattering (RIXS) and angle-resolved photoelectron spectroscopy (ARPES) are described. The photon source is an undulator of novel fixed-gap design where longitudinal movement of permanent magnetic arrays controls not only the light polarization (including circular and 0-180 degrees rotatable linear polarizations) but also the energy without changing the gap. The beamline optics is based on the well established scheme of plane-grating monochromator operating in collimated light. The ultimate resolving power E/DeltaE is above 33000 at 1 keV photon energy. The choice of blazed versus lamellar gratings and optimization of their profile parameters is described. Owing to glancing angles on the mirrors as well as optimized groove densities and profiles of the gratings, the beamline is capable of delivering high photon flux up to 1 x 10(13) photons s(-1) (0.01% BW)(-1) at 1 keV. Ellipsoidal refocusing optics used for the RIXS endstation demagnifies the vertical spot size down to 4 microm, which allows slitless operation and thus maximal transmission of the high-resolution RIXS spectrometer delivering E/DeltaE > 11000 at 1 keV photon energy. Apart from the beamline optics, an overview of the control system is given, the diagnostics and software tools are described, and strategies used for the optical alignment are discussed. An introduction to the concepts and instrumental realisation of the ARPES and RIXS endstations is given. PMID:20724785

  15. High-resolution soft X-ray beamline ADRESS at the Swiss Light Source for resonant inelastic X-ray scattering and angle-resolved photoelectron spectroscopies

    PubMed Central

    Strocov, V. N.; Schmitt, T.; Flechsig, U.; Schmidt, T.; Imhof, A.; Chen, Q.; Raabe, J.; Betemps, R.; Zimoch, D.; Krempasky, J.; Wang, X.; Grioni, M.; Piazzalunga, A.; Patthey, L.

    2010-01-01

    The concepts and technical realisation of the high-resolution soft X-ray beamline ADRESS operating in the energy range from 300 to 1600 eV and intended for resonant inelastic X-ray scattering (RIXS) and angle-resolved photoelectron spectroscopy (ARPES) are described. The photon source is an undulator of novel fixed-gap design where longitudinal movement of permanent magnetic arrays controls not only the light polarization (including circular and 0–180° rotatable linear polarizations) but also the energy without changing the gap. The beamline optics is based on the well established scheme of plane-grating monochromator operating in collimated light. The ultimate resolving power E/ΔE is above 33000 at 1 keV photon energy. The choice of blazed versus lamellar gratings and optimization of their profile parameters is described. Owing to glancing angles on the mirrors as well as optimized groove densities and profiles of the gratings, the beamline is capable of delivering high photon flux up to 1 × 1013 photons s−1 (0.01% BW)−1 at 1 keV. Ellipsoidal refocusing optics used for the RIXS endstation demagnifies the vertical spot size down to 4 µm, which allows slitless operation and thus maximal transmission of the high-resolution RIXS spectrometer delivering E/ΔE > 11000 at 1 keV photon energy. Apart from the beamline optics, an overview of the control system is given, the diagnostics and software tools are described, and strategies used for the optical alignment are discussed. An introduction to the concepts and instrumental realisation of the ARPES and RIXS endstations is given. PMID:20724785

  16. High-resolution angle-resolved photoemission studies of high Tc superconductor Bi sub 2 Sr sub 2 CaCu sub 2 O sub 8

    SciTech Connect

    Liu, Rong.

    1990-09-21

    An angle-resolved photoemission study of the normal and superconducting states in Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} was performed. Measurements in the normal state show bands dispersing through the Fermi level from at least 350 meV below E{sub F}. The Fermi level crossings are consistant with local-density band calculation, including a point calculated to be of Bi-O character. Additional measurements were made where bands crossed the Fermi level between 100 and 250K, along with measurements on an adjacent Pt foil. The Fermi edges of both materials agree to within the noise. Below the Fermi level, the spectra show correlation effects on the form of an increased effective mass. The shape of the spectra can be explained by a lifetime-broadened photohole and secondary electrons. The effective inverse photohole lifetime is linear in energy. A superconducting gap has been measured at a number of points where there is density at the Fermi level in the normal state. By proper modeling, a gap of 24 meV was obtained for all these points, including points of Cu-O and Bi-O character respectively, according to band calculation. The lack of gap anisotropy in the basal plane suggests that pinning in this material is not d-wave pairing.

  17. Improving the measurement performance of angle-resolved scattermetry by use of pupil optimization

    NASA Astrophysics Data System (ADS)

    Wang, Fan; Zhang, Qingyun; Lu, Hailiang; Duan, Lifeng; Li, Xiaoping

    2012-03-01

    As feature sizes decrease, requirements on critical dimension uniformity have become very strict. To monitor variations in lithography process and perform advanced process control it is important to establish a fast and accurate measurement technique for characterizing critical dimension, sidewall angle and height of the resist profile. Various techniques for feature measurement such as CD-SEM, AFM, FE-SEM, and scatterometry have been developed. Among these techniques, scatterometry has both high accuracy and a non-deconstructive measurement modality. It thus provides advantages of low-cost, high throughput, and robustness. Angle-resolved scatterometry has already been shown to provide in-line feedback information necessary for tight process control. In present paper, we introduce a novel angle-resolved scatterometer with pupil optimization. The intensity distribution of the incident light in the pupil plane is optimized considering the feature and the image sensor response properties, which improve the measurement performance of the scatterometer. A first order analysis of measurement sensitivity at different polarization conditions is carried out on resist-coated wafers with 45nm and 22nm features using Rigorous Coupled- Wave analysis (RCWA). Based on the criteria defined as the sum of the absolute difference of the relative intensity values between the nominal and varied conditions in the pupil, the sensitivity of the new technique and traditional scatterometer is compared. Simulation results show that, for 45nm feature, the sensitivity in s and p-polarization is increased by 400% and 300% respectively. While for 22nm feature, the sensitivity is increased by 200% and 130%. Reproducibility of measurement is also analyzed on 45nm and 22nm features using a Monte Carlo method and models for detector noise. Comparison of reproducibility for CD, sidewall angle, and resist height measurement is demonstrated.

  18. Angle-resolved scattering and reflectance of extreme-ultraviolet multilayer coatings: measurement and analysis

    SciTech Connect

    Schroeder, Sven; Herffurth, Tobias; Trost, Marcus; Duparre, Angela

    2010-03-20

    Roughness-induced light scattering critically affects the performance of optical components, in particular at short wavelengths. We present a stand-alone instrument for angle-resolved scattering and reflectance measurements at 13.5 nm in the extreme-ultraviolet (EUV) spectral range. The achieved dynamic range allows even the scattering of high-quality EUV mirrors on extremely smooth substrates to be investigated. For Mo/Si multilayers, total scatter losses of several percent have been observed, depending on the substrate qualities as well as on roughening and smoothing effects during coating. Different approximate models for estimating the impact of roughness on scatter losses are discussed and compared with experimental results.

  19. Comparison of models and measurements of angle-resolved scatter from irregular aerosols

    NASA Astrophysics Data System (ADS)

    Milstein, Adam B.; Richardson, Jonathan M.

    2015-01-01

    We have developed and validated a method for modeling the elastic scattering properties of biological and inert aerosols of irregular shape at near- and mid-wave infrared wavelengths. The method, based on Gaussian random particles, calculates the ensemble-average optical cross section and Mueller scattering matrix, using the measured aerodynamic size distribution and previously-reported refractive index as inputs. The utility of the Gaussian particle model is that it is controlled by only two parameters (σ and Γ) which we have optimized such that the model best reproduces the full angle-resolved Mueller scattering matrices measured at λ=1.55 μm in the Standoff Aerosol Active Signature Testbed (SAAST). The method has been applied to wet-generated singlet biological spore samples, dry-generated biological spore clusters, and kaolin. The scattering computation is performed using the Discrete Dipole Approximation (DDA), which requires significant computational resources, and is thus implemented on LLGrid, a large parallel grid computer. For the cases presented, the best fit Gaussian particle model is in good qualitative correspondence with microscopy images of the corresponding class of particles. The measured and computed cross sections agree well within a factor of two overall, with certain cases bearing closer correspondence. In particular, the DDA reproduces the shape of the measured scatter function more accurately than Mie predictions. The DDA-computed depolarization factors are also in good agreement with measurement.

  20. Complete Fermi Surface and Surface State in WTe2 Revealed by High-Resolution Laser-Based Angle-Resolved Photoemission Spectroscopy

    NASA Astrophysics Data System (ADS)

    Wang, Chenlu; Zhang, Yan; Liu, Guodong; Mao, Zhiqiang; He, Shaolong; Zhao, Lin; Chen, Chuangtian; Xu, Zuyan; Zhou, Xingjiang

    WTe2, an unique transition metal dichalcogenide, attracts considerable attention recently, which shows an extremely large magnetoresistance (MR) with no saturation under very high field. In this talk, we will present our high resolution laser-ARPES study on WTe2. Our distinctive ARPES system is equipped with the VUV laser and the time-of-flight (TOF) electron energy analyzer, being featured by super-high energy resolution, simultaneous data acquisition for two-dimensional momentum space and much reduced nonlinearity effect. With this advanced apparatus, the very high quality of electronic structure data are obtained for WTe2 which gives a full picture of the Fermi surface. Meanwhile, the obtained systematic temperature dependence of its electronic state leads us to a better understanding on the origin of large magnetoresistance in WTe2.

  1. High Resolution PDF Measurements on Ag Nanoparticles

    SciTech Connect

    Rocha, Tulio C. R.; Martin, Chris; Kycia, Stefan; Zanchet, Daniela

    2009-01-29

    The quantitative analysis of structural defects in Ag nanoparticles was addressed in this work. We performed atomic scale structural characterization by a combination of x-ray diffraction (XRD) using the Pair Distribution Function analysis (PDF) and High Resolution Transmission Electron Microscopy (HRTEM). The XRD measurements were performed using an innovative instrumentation setup to provide high resolution PDF patterns.

  2. Quantitative angle-resolved small-spot reflectance measurements on plasmonic perfect absorbers: impedance matching and disorder effects.

    PubMed

    Tittl, Andreas; Harats, Moshe G; Walter, Ramon; Yin, Xinghui; Schäferling, Martin; Liu, Na; Rapaport, Ronen; Giessen, Harald

    2014-10-28

    Plasmonic devices with absorbance close to unity have emerged as essential building blocks for a multitude of technological applications ranging from trace gas detection to infrared imaging. A crucial requirement for such elements is the angle independence of the absorptive performance. In this work, we develop theoretically and verify experimentally a quantitative model for the angular behavior of plasmonic perfect absorber structures based on an optical impedance matching picture. To achieve this, we utilize a simple and elegant k-space measurement technique to record quantitative angle-resolved reflectance measurements on various perfect absorber structures. Particularly, this method allows quantitative reflectance measurements on samples where only small areas have been nanostructured, for example, by electron-beam lithography. Combining these results with extensive numerical modeling, we find that matching of both the real and imaginary parts of the optical impedance is crucial to obtain perfect absorption over a large angular range. Furthermore, we successfully apply our model to the angular dispersion of perfect absorber geometries with disordered plasmonic elements as a favorable alternative to current array-based designs. PMID:25251075

  3. Development of a high-resolution soft x-ray (30--1500 eV) beamline at the Advanced Light Source and its use for the study of angle-resolved photoemission extended fine structure

    SciTech Connect

    Huff, W R.A.

    1996-02-01

    ALS Bending magnet beamline 9.3.2 is for high resolution spectroscopy, with circularly polarized light. Fixed included-angle SGM uses three gratings for 30--1500 eV photons; circular polarization is produced by an aperture for selecting the beam above or below the horizontal plane. Photocurrent from upper and lower jaws of entrance slit sets a piezoelectric drive feedback loop on the vertically deflecting mirror for stable beam. End station has a movable platform. With photomeission data from Stanford, structure of c(2{times}2)P/Fe(100) was determined using angle-resolved photoemission extended fine structure (ARPEFS). Multiple-scattering spherical-wave (MSSW) calculations indicate that P atoms adsorb in fourfold hollow sites 1.02A above the first Fe layer. Self-consistent-field X{alpha} scattered wave calculation confirm that the Fe{sub 1}-Fe{sub 2} space is contracted for S/Fe but not for P/Fe; comparison is made to atomic N and O on Fe(100). Final-state effects on ARPEFS curves used literature data from the S 1s and 2p core levels of c(2{times}2)S/Ni(001); a generalized Ramsauer-Townsend splitting is present in the 1s but not 2p data. An approximate method for analyzing ARPEFS data from a non-s initial state using only the higher-{ell} partial wave was tested successfully. ARPEFS data from clean surfaces were collected normal to Ni(111) (3p core levels) and 5{degree} off-normal from Cu(111)(3s, 3p). Fourier transforms (FT) resemble adsorbate systems, showing backscattering signals from atoms up to 4 layers below emitters. 3p FTs show scattering from 6 nearest neighbors in the same crystal layer as the emitters. MSSW calulation indicate that Cu 3p photoemission is mostly d-wave. FTs also indicate double-scattering and single-scattering from laterally distant atoms; calculations indicate that the signal is dominated by photoemission from the first 2 crystal layers.

  4. A Portable, High Resolution, Surface Measurement Device

    NASA Technical Reports Server (NTRS)

    Ihlefeld, Curtis M.; Burns, Bradley M.; Youngquist, Robert C.

    2012-01-01

    A high resolution, portable, surface measurement device has been demonstrated to provide micron-resolution topographical plots. This device was specifically developed to allow in-situ measurements of defects on the Space Shuttle Orbiter windows, but is versatile enough to be used on a wide variety of surfaces. This paper discusses the choice of an optical sensor and then the decisions required to convert a lab bench optical measurement device into an ergonomic portable system. The necessary trade-offs between performance and portability are presented along with a description of the device developed to measure Orbiter window defects.

  5. High Resolution Spectroscopy to Support Atmospheric Measurements

    NASA Technical Reports Server (NTRS)

    Benner, D. Chris; Venkataraman, Malathy Devi

    2000-01-01

    The major research activities performed during the cooperative agreement enhanced our spectroscopic knowledge of molecules of atmospheric interest such as carbon dioxide, water vapor, ozone, methane, and carbon monoxide, to name a few. Measurements were made using the NASA Langley Tunable Diode Laser Spectrometer System (TDL) and several Fourier Transform Spectrometer Systems (FTS) around the globe. The results from these studies made remarkable improvements in the line positions and intensities for several molecules, particularly ozone and carbon dioxide in the 2 to 17-micrometer spectral region. Measurements of pressure broadening and pressure induced line shift coefficients and the temperature dependence of pressure broadening and pressure induced line shift coefficients for infrared transitions of ozone, methane, and water vapor were also performed. Results from these studies have been used for retrievals of stratospheric gas concentration profiles from data collected by several Upper Atmospheric Research satellite (UARS) infrared instruments as well as in the analysis of high resolution atmospheric spectra such as those acquired by space-based, ground-based, and various balloon-and aircraft-borne experiments. Our results made significant contributions in several updates of the HITRAN (HIgh resolution TRANsmission) spectral line parameters database. This database enjoys worldwide recognition in research involving diversified scientific fields.

  6. High Resolution Acoustoelastic Measurements of Materials

    NASA Astrophysics Data System (ADS)

    McKenna, Mark; Guy, Samuel; Heyman, Joseph

    2006-11-01

    As materials become more complex, there is an increasing need for high resolution measurements to characterize strength and damage in the materials. Typically, the criterion for rejecting a part is based on the detection of a flaw of a specific size in a critical location. Interestingly, if a low stress field exists at the flaw site, the flaw may not grow over time. Similarly, in a part that shows no unacceptable indications, a high stress state may cause the flaw to quickly grow through the part leading to failure. In other cases, a controlled amount of stress (in a specific direction or type) is purposely added to the material to prevent flaw growth. Inspection time intervals are based knowing and controlling the stress environment to predict the flaw growth. Luna Innovations Incorporated has developed a high resolution ultrasonic instrument that can enhance the integrity of critical hardware by measuring changes in the stress state in a material. Knowledge of the stress state plus knowledge of crack sizes greatly improves structural engineers' capability of life prediction. System data will be shown for tests to stresses near holes in laboratory fabricated aircraft metal samples. Scans of the spatial distribution of stresses will be compared with finite element models of the structure.

  7. High Resolution Spectroscopy to Support Atmospheric Measurements

    NASA Technical Reports Server (NTRS)

    Benner, D. Chris; Venkataraman, Malathy Devi

    2000-01-01

    The major research activities performed during the cooperative agreement enhanced our spectroscopic knowledge of molecules of atmospheric interest such as carbon dioxide, water vapor, ozone, methane, and carbon monoxide, to name a few. Measurements were made using the NASA Langley Tunable Diode Laser Spectrometer System (TDL) and several Fourier Transform Spectrometer Systems (FTS) around the globe. The results from these studies made remarkable improvements in the line positions and intensities for several molecules, particularly ozone and carbon dioxide in the 2 to 17-micrometer spectral region. Measurements of pressure broadening and pressure induced line shift coefficients and the temperature dependence of pressure broadening and pressure induced line shift coefficients for infrared transitions of ozone, methane, and water vapor were also performed. Results from these studies have been used for retrievals of stratospheric gas concentration profiles from data collected by several Upper Atmospheric Research satellite (UARS) infrared instruments as well as in the analysis of high resolution atmospheric spectra such as those acquired by space-based, ground-based, and various balloon- and aircraft-borne experiments. Our results made significant contributions in several updates of the HITRAN (HIgh resolution TRANsmission) spectral line parameters database. This database enjoys worldwide recognition in research involving diversified scientific fields.

  8. Analyzing spatial correlations in tissue using angle-resolved low coherence interferometry measurements guided by co-located optical coherence tomography

    PubMed Central

    Kim, Sanghoon; Heflin, Stephanie; Kresty, Laura A.; Halling, Meredith; Perez, Laura N.; Ho, Derek; Crose, Michael; Brown, William; Farsiu, Sina; Arshavsky, Vadim; Wax, Adam

    2016-01-01

    Angle-resolved low coherence interferometry (a/LCI) is an optical technique used to measure nuclear morphology in situ. However, a/LCI is not an imaging modality and can produce ambiguous results when the measurements are not properly oriented to the tissue architecture. Here we present a 2D a/LCI system which incorporates optical coherence tomography imaging to guide the measurements. System design and characterization are presented, along with example cases which demonstrate the utility of the combined measurements. In addition, future development and applications of this dual modality approach are discussed. PMID:27446664

  9. Analyzing spatial correlations in tissue using angle-resolved low coherence interferometry measurements guided by co-located optical coherence tomography.

    PubMed

    Kim, Sanghoon; Heflin, Stephanie; Kresty, Laura A; Halling, Meredith; Perez, Laura N; Ho, Derek; Crose, Michael; Brown, William; Farsiu, Sina; Arshavsky, Vadim; Wax, Adam

    2016-04-01

    Angle-resolved low coherence interferometry (a/LCI) is an optical technique used to measure nuclear morphology in situ. However, a/LCI is not an imaging modality and can produce ambiguous results when the measurements are not properly oriented to the tissue architecture. Here we present a 2D a/LCI system which incorporates optical coherence tomography imaging to guide the measurements. System design and characterization are presented, along with example cases which demonstrate the utility of the combined measurements. In addition, future development and applications of this dual modality approach are discussed. PMID:27446664

  10. High Resolution Spectroscopy to Support Atmospheric Measurements

    NASA Technical Reports Server (NTRS)

    Venkataraman, Malathy Devi

    2006-01-01

    The major research activities performed during the cooperative agreement enhanced our spectroscopic knowledge of molecules of atmospheric interest such as H2O (water vapor), O3 (ozone), HCN (hydrogen cyanide), CH4 (methane), NO2 (nitrogen dioxide) and CO (carbon monoxide). The data required for the analyses were obtained from two different Fourier Transform Spectrometers (FTS); one of which is located at the National Solar Observatory (NSO) on Kitt Peak, Arizona and the other instrument is located at the Pacific Northwest National Laboratories (PNNL) at Richland, Washington. The data were analyzed using a modified multispectrum nonlinear least squares fitting algorithm developed by Dr. D. Chris Benner of the College of William and Mary. The results from these studies made significant improvements in the line positons and intensities for these molecules. The measurements of pressure broadening and pressure induced line shift coefficients and the temperature dependence of pressure broadening and pressure induced shift coefficients for hundreds of infrared transitions of HCN, CO3 CH4 and H2O were also performed during this period. Results from these studies have been used for retrievals of stratospheric gas concentration profiles from data collected by several Upper Atmospheric Research Satellite (UARS) infrared instruments as well as in the analysis of high resolution atmospheric spectra such as those acquired by space-based, ground-based, and various balloon- and aircraft-borne experiments. Our results made significant contributions in several updates of the HITRAN (HIgh resolution TRANsmission) spectral line parameters database. This database enjoys worldwide recognition in research involving diversified scientific fields. The research conducted during the period 2003-2006 has resulted in publications given in this paper. In addition to Journal publications, several oral and poster presentations were given at various Scientific conferences within the United States

  11. Electronic structure of Au-induced surface phases on Si(110): LEED and angle-resolved photoemission measurements

    NASA Astrophysics Data System (ADS)

    Kang, Se Hun; Kim, Keun Su; Yeom, Han Woong

    2008-08-01

    Au-induced reconstructions of the Si(110) surface have been studied using low-energy electron diffraction and angle-resolved photoemission (ARP). Low-energy electron diffraction reveals three well-ordered phases: 1×2 , 2×5 , and (4,0)×(1¯,3) , depending on the Au coverage in accordance with previous studies. The highest coverage phase is observed to be mixed with a (4,0)×(3¯,3) phase. ARP spectra show no clear surface-state bands on the 1×2 surface within the bulk band gap. The 2×5 surface composed of one-dimensional (1D) atomic chain exhibits two dispersive metallic bands with exact quarter and half fillings. Their Fermi surfaces are straight lines within the experimental accuracy indicating strong 1D characters. This phase is thus one of the most ideal 1D metallic systems ever fabricated on solid surfaces. The (4,0)×(1¯,3) surface has only one strongly dispersing but semiconducting band following the ×2 periodicity apparently.

  12. High Resolution Spectroscopy to Support Atmospheric Measurements

    NASA Technical Reports Server (NTRS)

    Venkataraman, Malathy Devi

    2003-01-01

    Spectroscopic parameters (such as line position, intensity, broadening and shifting coefficients and their temperature dependences, line mixing coefficients etc.) for various molecular species of atmospheric interest are determined. In order to achieve these results, infrared spectra of several molecular bands are obtained using high-resolution recording instruments such as tunable diode laser spectrometer and Fourier transform spectrometers. Using sophisticated analysis routines (Multispectrum nonlinear least squares technique) these high-resolution infrared spectra are processed to determine the various spectral line parameters that are cited above. Spectra were taken using the McMath-Pierce Fourier transform spectrometer (FTS) at the National Solar Observatory on Kitt Peak, Arizona as well as the Bruker FTS at the Pacific Northwest National Laboratory (PNNL) at Richland, Washington. Most of the spectra are acquired not only at room temperature, but also at several different cold temperatures. This procedure is necessary to study the variation of the spectral line parameters as a function of temperature in order to simulate the Earth's and other planetary atmospheric environments. Depending upon the strength or weakness of the various bands recorded and analyzed, the length(s) of the absorption cells in which the gas samples under study are kept varied from a few centimeters up to several meters and the sample temperatures varied from approximately +30 C to -63 C. Research on several infrared bands of various molecular species and their isotopomers are undertaken. Those studies are briefly described.

  13. High resolution spectroscopy to support atmospheric measurements

    NASA Technical Reports Server (NTRS)

    Smith, Mary Ann H.; Devi, V. Malathy; Rinsland, Curtis P.; Benner, D. Chris; Harvey, Gale A.

    1990-01-01

    Detailed knowledge of the molecular spectra of ozone and other infrared-active atmospheric species is needed for accurate calculation of atmospheric heating and cooling rates in climate models. Remote sensing experiments on the Nimbus-7 satellites and the Spacelab-3 Space Shuttle Mission have shown that space-based measurements of infrared absorption or emission can be used to accurately determine the concentrations and distributions of stratospheric species on a global scale. The objective of this research task is to improve knowledge of the spectroscopic line parameters (positions, intensities, assignments, halfwidths, and pressure-induced shifts) of key atmospheric constituents through laboratory measurements.

  14. Electronic Structure of Epitaxial Thin Films of the Transparent Conducting Oxide La:BaSnO3 Measured By In-Situ Angle-Resolved Photoemission Spectroscopy

    NASA Astrophysics Data System (ADS)

    Lochocki, Edward; Paik, Hanjong; Uchida, Masaki; Schlom, Darrell; Shen, Kyle

    Lanthanum-doped barium stannate (La:BaSnO3) is a transparent conducting oxide where single crystals have exhibited unusually high mobility and oxygen stability. Here we present in-situ angle-resolved photoemission (ARPES) measurements of La:BaSnO3 epitaxial films that were co-deposited onto lattice-matched rare-earth scandate substrates by molecular-beam epitaxy (MBE). Density functional theory (DFT) calculations agree well with the observed valence bands and predict a parabolic conduction band. However, the features observed near the Fermi energy (EF) are non-dispersive yet localized in momentum space. This unusual appearance may be the result of quasi-localized charge carriers or out-of-plane momentum broadening. Over long measurement periods, we also observe changes to the valence band and near-EF feature that bear a strong resemblance to the beam-induced two-dimensional electron gases previously reported in SrTiO3 and KTaO3. The origin of these unexpected phenomena and their relationship to the structural and transport properties of these films will be discussed.

  15. Omnidirectional Measurements of Angle-Resolved Heat Capacity for Complete Detection of Superconducting Gap Structure in the Heavy-Fermion Antiferromagnet UPd_{2}Al_{3}.

    PubMed

    Shimizu, Yusei; Kittaka, Shunichiro; Sakakibara, Toshiro; Tsutsumi, Yasumasa; Nomoto, Takuya; Ikeda, Hiroaki; Machida, Kazushige; Homma, Yoshiya; Aoki, Dai

    2016-07-15

    Quasiparticle excitations in UPd_{2}Al_{3} were studied by means of heat-capacity (C) measurements under rotating magnetic fields using a high-quality single crystal. The field dependence shows C(H)∝H^{1/2}-like behavior at low temperatures for both two hexagonal crystal axes, i.e., H∥[0001] (c axis) and H∥[112[over ¯]0] (a axis), suggesting the presence of nodal quasiparticle excitations from heavy bands. At low temperatures, the polar-angle (θ) dependence of C exhibits a maximum along H∥[0001] with a twofold symmetric oscillation below 0.5 T, and an unusual shoulder or hump anomaly has been found around 30°-60° from the c axis in C(θ) at intermediate fields (1≲μ_{0}H≲2  T). These behaviors in UPd_{2}Al_{3} purely come from the superconducting nodal quasiparticle excitations, and can be successfully reproduced by theoretical calculations assuming the gap symmetry with a horizontal linear line node. We demonstrate the whole angle-resolved heat-capacity measurements done here as a novel spectroscopic method for nodal gap determination, which can be applied to other exotic superconductors. PMID:27472129

  16. A promising concept for using near-surface measuring angles in angle-resolved x-ray photoelectron spectroscopy considering elastic scattering effects

    SciTech Connect

    Oswald, S.; Oswald, F.

    2011-02-01

    The increasing number of applications of very thin films requires both reliable thin-layer and interface characterization. A powerful method for characterization in the nanometer thickness range is the angle-resolved x-ray photoelectron spectroscopy (ARXPS). This is a nondestructive depth-profiling method, which can provide elemental content as well as chemical information. Two of the drawbacks of ARXPS are, that it requires dedicated mathematical modeling and that, at least up until now, its use has been restricted away from near-surface angles. In this paper we present a method for the mathematical description of a few, hitherto unaccounted, measurement effects in order to improve the simulations of ARXPS data for complex surface structures. As an immediate application, we propose a simple algorithm to consider the effects of elastic scattering in the standard ARXPS data interpretation, which in principle would allow the use of the whole angular range for the analysis; thus leading to a significant increase in the usable information content from the measurements. The potential of this approach is demonstrated with model calculations for a few thin film examples.

  17. Omnidirectional Measurements of Angle-Resolved Heat Capacity for Complete Detection of Superconducting Gap Structure in the Heavy-Fermion Antiferromagnet UPd2 Al3

    NASA Astrophysics Data System (ADS)

    Shimizu, Yusei; Kittaka, Shunichiro; Sakakibara, Toshiro; Tsutsumi, Yasumasa; Nomoto, Takuya; Ikeda, Hiroaki; Machida, Kazushige; Homma, Yoshiya; Aoki, Dai

    2016-07-01

    Quasiparticle excitations in UPd2 Al3 were studied by means of heat-capacity (C ) measurements under rotating magnetic fields using a high-quality single crystal. The field dependence shows C (H )∝H1 /2-like behavior at low temperatures for both two hexagonal crystal axes, i.e., H ∥[0001 ] (c axis) and H ∥[11 2 ¯0 ] (a axis), suggesting the presence of nodal quasiparticle excitations from heavy bands. At low temperatures, the polar-angle (θ ) dependence of C exhibits a maximum along H ∥[0001 ] with a twofold symmetric oscillation below 0.5 T, and an unusual shoulder or hump anomaly has been found around 30°-60° from the c axis in C (θ ) at intermediate fields (1 ≲μ0H ≲2 T ). These behaviors in UPd2 Al3 purely come from the superconducting nodal quasiparticle excitations, and can be successfully reproduced by theoretical calculations assuming the gap symmetry with a horizontal linear line node. We demonstrate the whole angle-resolved heat-capacity measurements done here as a novel spectroscopic method for nodal gap determination, which can be applied to other exotic superconductors.

  18. Fermi surface of MoO2 studied by angle-resolved photoemission spectroscopy, de Haas-van Alphen measurements, and electronic structure calculations

    NASA Astrophysics Data System (ADS)

    Moosburger-Will, Judith; Kündel, Jörg; Klemm, Matthias; Horn, Siegfried; Hofmann, Philip; Schwingenschlögl, Udo; Eyert, Volker

    2009-03-01

    A comprehensive study of the electronic properties of monoclinic MoO2 from both an experimental and a theoretical point of view is presented. We focus on the investigation of the Fermi body and the band structure using angle-resolved photoemission spectroscopy, de Haas-van Alphen measurements, and electronic structure calculations. For the latter, the full-potential augmented spherical wave method has been applied. Very good agreement between the experimental and theoretical results is found. In particular, all Fermi surface sheets are correctly identified by all three approaches. Previous controversies concerning additional holelike surfaces centered around the Z and B points could be resolved; these surfaces were artifacts of the atomic-sphere approximation used in the old calculations. Our results underline the importance of electronic structure calculations for the understanding of MoO2 and the neighboring rutile-type early transition-metal dioxides. This includes the low-temperature insulating phases of VO2 and NbO2 , which have crystal structures very similar to that of molybdenum dioxide and display the well-known prominent metal-insulator transitions.

  19. Angle-resolved photoemission extended fine structure

    SciTech Connect

    Barton, J.J.

    1985-03-01

    Measurements of the Angle-Resolved Photoemission Extended Fine Structure (ARPEFS) from the S(1s) core level of a c(2 x 2)S/Ni(001) are analyzed to determine the spacing between the S overlayer and the first and second Ni layers. ARPEFS is a type of photoelectron diffraction measurement in which the photoelectron kinetic energy is swept typically from 100 to 600 eV. By using this wide range of intermediate energies we add high precision and theoretical simplification to the advantages of the photoelectron diffraction technique for determining surface structures. We report developments in the theory of photoelectron scattering in the intermediate energy range, measurement of the experimental photoemission spectra, their reduction to ARPEFS, and the surface structure determination from the ARPEFS by combined Fourier and multiple-scattering analyses. 202 refs., 67 figs., 2 tabs.

  20. High-Resolution Wind Measurements for Offshore Wind Energy Development

    NASA Technical Reports Server (NTRS)

    Nghiem, Son V.; Neumann, Gregory

    2011-01-01

    A mathematical transform, called the Rosette Transform, together with a new method, called the Dense Sampling Method, have been developed. The Rosette Transform is invented to apply to both the mean part and the fluctuating part of a targeted radar signature using the Dense Sampling Method to construct the data in a high-resolution grid at 1-km posting for wind measurements over water surfaces such as oceans or lakes.

  1. High Resolution Measurements and Electronic Structure Calculations of a Diazanaphthalene

    NASA Astrophysics Data System (ADS)

    Gruet, Sébastien; Goubet, Manuel; Pirali, Olivier

    2014-06-01

    Polycyclic Aromatic Hydrocarbons (PAHs) have long been suspected to be the carriers of so called Unidentified Infrared Bands (UIBs). Most of the results published in the literature report rotationally unresolved spectra of pure carbon as well as heteroatom-containing PAHs species. To date for this class of molecules, the principal source of rotational informations is ruled by microwave (MW) spectroscopy while high resolution measurements reporting rotational structure of the infrared (IR) vibrational bands are very scarce. Recently, some high resolution techniques provided interesting new results to rotationally resolve the IR and far-IR bands of these large carbonated molecules of astrophysical interest. One of them is to use the bright synchrotron radiation as IR continuum source of a high resolution Fourier transform (FTIR) spectrometer. We report the very complementary analysis of the [1,6] naphthyridine (a N-bearing PAH) for which we recorded the microwave spectrum at the PhLAM laboratory (Lille) and the high resolution far-infrared spectrum on the AILES beamline at synchrotron facility SOLEIL. MW spectroscopy provided highly accurate rotational constants in the ground state to perform Ground State Combinations Differences (GSCD) allowing the analysis of the two most intense FT-FIR bands in the 50-900 wn range. Moreover, during this presentation the negative value of the inertial defect in the GS of the molecule will be discussed. A. Leger, J. L. Puget, Astron. Astrophys. 137, L5-L8 (1984) L. J. Allamandola et al. Astrophys. J. 290, L25-L28 (1985). Z. Kisiel et al. J. Mol. Spectrosc. 217, 115 (2003) S. Thorwirth et al. Astrophys. J. 662, 1309 (2007) D. McNaughton et al. J. Chem. Phys. 124, 154305 (2011). S. Albert et al. Faraday Discuss. 150, 71-99 (2011) B. E. Brumfield et al. Phys. Chem. Lett. 3, 1985-1988 (2012) O. Pirali et al. Phys. Chem. Chem. Phys. 15, 10141 (2013).

  2. Wide and high resolution tension measurement using FRET in embryo.

    PubMed

    Yamashita, Satoshi; Tsuboi, Takashi; Ishinabe, Nanako; Kitaguchi, Tetsuya; Michiue, Tatsuo

    2016-01-01

    During embryonic development, physical force plays an important role in morphogenesis and differentiation. Stretch sensitive fluorescence resonance energy transfer (FRET) has the potential to provide non-invasive tension measurements inside living tissue. In this study, we introduced a FRET-based actinin tension sensor into Xenopus laevis embryos and demonstrated that this sensor captures variation of tension across differentiating ectoderm. The actinin tension sensor, containing mCherry and EGFP connected by spider silk protein, was validated in human embryonic kidney (HEK) cells and embryos. It co-localized with actin filaments and changed FRET efficiencies in response to actin filament destruction, myosin deactivation, and osmotic perturbation. Time-lapse FRET analysis showed that the prospective neural ectoderm bears higher tension than the epidermal ectoderm during gastrulation and neurulation, and cells morphogenetic behavior correlated with the tension difference. These data confirmed that the sensor enables us to measure tension across tissues concurrently and with high resolution. PMID:27335157

  3. Wide and high resolution tension measurement using FRET in embryo

    PubMed Central

    Yamashita, Satoshi; Tsuboi, Takashi; Ishinabe, Nanako; Kitaguchi, Tetsuya; Michiue, Tatsuo

    2016-01-01

    During embryonic development, physical force plays an important role in morphogenesis and differentiation. Stretch sensitive fluorescence resonance energy transfer (FRET) has the potential to provide non-invasive tension measurements inside living tissue. In this study, we introduced a FRET-based actinin tension sensor into Xenopus laevis embryos and demonstrated that this sensor captures variation of tension across differentiating ectoderm. The actinin tension sensor, containing mCherry and EGFP connected by spider silk protein, was validated in human embryonic kidney (HEK) cells and embryos. It co-localized with actin filaments and changed FRET efficiencies in response to actin filament destruction, myosin deactivation, and osmotic perturbation. Time-lapse FRET analysis showed that the prospective neural ectoderm bears higher tension than the epidermal ectoderm during gastrulation and neurulation, and cells morphogenetic behavior correlated with the tension difference. These data confirmed that the sensor enables us to measure tension across tissues concurrently and with high resolution. PMID:27335157

  4. Measuring Large-Scale Social Networks with High Resolution

    PubMed Central

    Stopczynski, Arkadiusz; Sekara, Vedran; Sapiezynski, Piotr; Cuttone, Andrea; Madsen, Mette My; Larsen, Jakob Eg; Lehmann, Sune

    2014-01-01

    This paper describes the deployment of a large-scale study designed to measure human interactions across a variety of communication channels, with high temporal resolution and spanning multiple years—the Copenhagen Networks Study. Specifically, we collect data on face-to-face interactions, telecommunication, social networks, location, and background information (personality, demographics, health, politics) for a densely connected population of 1 000 individuals, using state-of-the-art smartphones as social sensors. Here we provide an overview of the related work and describe the motivation and research agenda driving the study. Additionally, the paper details the data-types measured, and the technical infrastructure in terms of both backend and phone software, as well as an outline of the deployment procedures. We document the participant privacy procedures and their underlying principles. The paper is concluded with early results from data analysis, illustrating the importance of multi-channel high-resolution approach to data collection. PMID:24770359

  5. High-resolution terahertz atmospheric water vapor continuum measurements

    NASA Astrophysics Data System (ADS)

    Slocum, David M.; Goyette, Thomas M.; Giles, Robert H.

    2014-05-01

    The terahertz frequency regime is often used as the `chemical fingerprint' region of the electromagnetic spectrum due to the large number of rotational and vibrational transitions of many molecules of interest. This region of the spectrum has particular utility for applications such as pollution monitoring and the detection of energetic chemicals using remote sensing over long path lengths through the atmosphere. Although there has been much attention to atmospheric effects over narrow frequency windows, accurate measurements across a wide spectrum are lacking. The water vapor continuum absorption is an excess absorption that is unaccounted for in resonant line spectrum simulations. Currently a semiempirical model is employed to account for this absorption, however more measurements are necessary to properly describe the continuum absorption in this region. Fourier Transform Spectroscopy measurements from previous work are enhanced with high-resolution broadband measurements in the atmospheric transmission window at 1.5THz. The transmission of broadband terahertz radiation through pure water vapor as well as air with varying relative humidity levels was recorded for multiple path lengths. The pure water vapor measurements provide accurate determination of the line broadening parameters and experimental measurements of the transition strengths of the lines in the frequency region. Also these measurements coupled with the atmospheric air measurements allow the water vapor continuum absorption to be independently identified at 1.5THz. Simulations from an atmospheric absorption model using parameters from the HITRAN database are compared with the current and previous experimental results.

  6. High-Resolution, Single-Molecule Measurements of Biomolecular Motion

    PubMed Central

    Greenleaf, William J.; Woodside, Michael T.; Block, Steven M.

    2007-01-01

    Many biologically important macromolecules undergo motions that are essential to their function. Biophysical techniques can now resolve the motions of single molecules down to the nanometer scale or even below, providing new insights into the mechanisms that drive molecular movements. This review outlines the principal approaches that have been used for high-resolution measurements of single-molecule motion, including centroid tracking, fluorescence resonance energy transfer, magnetic tweezers, atomic force microscopy, and optical traps. For each technique, the principles of operation are outlined, the capabilities and typical applications are examined, and various practical issues for implementation are considered. Extensions to these methods are also discussed, with an eye toward future application to outstanding biological problems. PMID:17328679

  7. High resolution rainfall measurements around a high rise building

    NASA Astrophysics Data System (ADS)

    de Jong, Stijn; van de Giesen, Nick; Hut, Rolf

    2010-05-01

    A number of disdrometers (acoustic rain gauge) has been placed around a high rise building on a place where variation in spatial distribution of precipitation is expected, to show the advantage of high resolution rainfall measurements in a urban area. The standard recommendation for the placement of a rain gauge is that the gauge is positioned at a distance corresponding to two to four times the height of any nearby obstruction to obtain a measurement that is representative for the surrounding area. In an urban area it is almost impossible to find a location that suits this recommendation. Rain measurements in urban area with a high spatial resolution are desired, to obtain a better understanding of urban hydrology, but costs may be prohibitive. A low cost disdrometer has been developed to make it affordable to perform rain measurements with a very high spatial and temporal resolution. The disdrometer is tested around a high rise building on the Delft University of Technology campus. The faculty of Electrical Engineering, Mathematics and Computer Science (EWI) on the campus of Delft University of Technology consists of a high rise building of 90 meters and a low rise building of 15 meters. Sensors are placed on the low rise building to measure the impact of the high rise building on the spatial distribution of precipitation. In addition to the disdrometer, two other methods are used to measure precipitation differences around the high rise building. Tipping bucket rain gauges have been placed on two elevator shaft housings on the low rise building, of which one is situated in the shadow of the high rise building. Simultaneously, runoff from the elevator shafts is measured. A comparison of the different methods will be presented.

  8. Quantized Electron Accumulation States in Indium Nitride Studied by Angle-Resolved Photoemission Spectroscopy

    NASA Astrophysics Data System (ADS)

    Colakerol, Leyla; Veal, T. D.; Jeong, Hae-Kyung; Plucinski, Lukasz; Demasi, Alex; Learmonth, Timothy; Glans, Per-Anders; Wang, Shancai; Zhang, Yufeng; Piper, L. F. J.; Jefferson, P. H.; Fedorov, Alexei; Chen, Tai-Chou; Moustakas, T. D.; McConville, C. F.; Smith, Kevin E.

    2006-12-01

    Electron accumulation states in InN have been measured using high resolution angle-resolved photoemission spectroscopy (ARPES). The electrons in the accumulation layer have been discovered to reside in quantum well states. ARPES was also used to measure the Fermi surface of these quantum well states, as well as their constant binding energy contours below the Fermi level EF. The energy of the Fermi level and the size of the Fermi surface for these quantum well states could be controlled by varying the method of surface preparation. This is the first unambiguous observation that electrons in the InN accumulation layer are quantized and the first time the Fermi surface associated with such states has been measured.

  9. High-resolution measurements of humidity and temperature with lidar

    NASA Astrophysics Data System (ADS)

    Behrendt, Andreas; Wulfmeyer, Volker; Spaeth, Florian; Hammann, Eva; Muppa, Shravan Kumar; Metzendorf, Simon; Riede, Andrea

    2015-04-01

    3-dimensional thermodynamic fields of temperature and moisture including their turbulent fluctuations have been observed with the two scanning lidar systems of University of Hohenheim in three field campaigns in 2013 and 2014. In this contribution, we will introduce these two self-developed instruments and illustrate their performance with measurement examples. Finally, an outlook to envisioned future research activities with the new data sets of the instruments is given. Our temperature lidar is based on the rotational Raman technique. The scanning rotational Raman lidar (RRL) uses a seeded frequency-doubled Nd:YAG laser at a wavelength of 355 nm. A two-mirror scanner with a 40-cm telescope collects the atmospheric backscatter signals. Humidity measurements are made with a scanning water vapor differential absorption lidar (DIAL) which uses a titanium sapphire laser at 820 nm as transmitter. This laser is pumped with a frequency-doubled Nd:YAG laser and injection-seeded for switching between the online and offline wavelengths. The DIAL receiver consists of a scanning 80-cm telescope. The measured temperature and humidity profiles of both instruments have typical resolutions of only a few seconds and 100 m in the atmospheric boundary layer both in day- and night-time. Recent field experiments with the RRL and the DIAL of University of Hohenheim were (1) the HD(CP)2 Prototype Experiment (HOPE) in spring 2013 in western Germany - this activity is embedded in the project HD(CP)2 (High-definition clouds and precipitation for advancing climate prediction); (2) a measurement campaign in Hohenheim in autumn 2013; (3) the campaign SABLE (Surface Atmospheric Boundary Layer Exchange) in south-western Germany in summer 2014. The collected moisture and temperature data will serve as initial thermodynamic fields for forecast experiments related to the formation of clouds and precipitation. Due to their high resolution and high precision, the systems are capable of resolving

  10. High Resolution Measurement of Auroral "Hiss" and "Roar"

    NASA Astrophysics Data System (ADS)

    Ye, S.; Labelle, J.; Weatherwax, A.

    2004-05-01

    In December 2002, a Versatile Electromagnetic Wave Receiver (VIEW) together with a new digitization system was deployed at South Pole station. The motivation was to measure three types of auroral radio emissions: Auroral Roar, a relatively narrowband (Δ f/f <0.1) emission near 2 and 3 times the F region ionospheric electron cyclotron frequency (fce); Auroral Hiss, a whistler mode wave emission with frequencies lower than 1MHz ; and Auroral medium frequency (MF) burst, broadband impulsive radio emissions observed at ground level during the breakup phase of auroral substorms. High resolution broad band structure of those three emissions are recorded automatically at South Pole, and are crucial to our understanding the mechanism and relations of auroral radio emissions. This experiment uses a 3x3 meter square magnetic dipole antenna, located 1.7 km away from the South Pole station. A pre-amplifier is buried right below the eastern pylon of the antenna, connected by a 1.7 km long co-axial cable to a LF-HF receiver in the station. The output of the receiver is fed into the Versatile Electromagnetic Wave Receiver (VIEW) and Windows system equipped with a digitization board. Software is written to digitize the selected signals at 1 or 2 MHz. This data acquisition system was designed so that researchers at Dartmouth College can review the data from South Pole weekly and save interesting parts according to instructions sent from Dartmouth. In the year of 2003, the experiment concentrated on the auroral roar frequency band. With 3 hours window per day, it captured more than 30 auroral roar events at South Pole station. The data show detailed structure of Auroral Roar, which is comprised of multiple narrow band features drifting in frequencies in a complicated pattern. ( LaBelle et al., 1995; Shepherd et al., 1998) Starting in 2004, the experiment is concentrating on the auroral hiss frequency band. This mode promises to caputure the first detailed structure of auroral hiss

  11. Angle-resolved diffraction grating biosensor based on porous silicon

    NASA Astrophysics Data System (ADS)

    Lv, Changwu; Jia, Zhenhong; Liu, Yajun; Mo, Jiaqing; Li, Peng; Lv, Xiaoyi

    2016-03-01

    In this study, an optical biosensor based on a porous silicon composite structure was fabricated using a simple method. This structure consists of a thin, porous silicon surface diffraction grating and a one-dimensional porous silicon photonic crystal. An angle-resolved diffraction efficiency spectrum was obtained by measuring the diffraction efficiency at a range of incident angles. The angle-resolved diffraction efficiency of the 2nd and 3rd orders was studied experimentally and theoretically. The device was sensitive to the change of refractive index in the presence of a biomolecule indicated by the shift of the diffraction efficiency spectrum. The sensitivity of this sensor was investigated through use of an 8 base pair antifreeze protein DNA hybridization. The shifts of the angle-resolved diffraction efficiency spectrum showed a relationship with the change of the refractive index, and the detection limit of the biosensor reached 41.7 nM. This optical device is highly sensitive, inexpensive, and simple to fabricate. Using shifts in diffraction efficiency spectrum to detect biological molecules has not yet been explored, so this study establishes a foundation for future work.

  12. High Resolution Measurement of LF Auroral Hiss at South Pole

    NASA Astrophysics Data System (ADS)

    Ye, S.; Labelle, J.

    2005-05-01

    In December 2002, a Versatile Electromagnetic Wave Receiver (VIEW) and a new digitization system were deployed at South Pole station(-74° magnetic latitude). The motivation was to measure three types of auroral radio emissions: Auroral Roar, a relatively narrowband (δf/f<0.1) emission near 2 and 3 times the F region ionospheric electron cyclotron frequency (fce); Auroral Hiss, a whistler mode wave emission with frequencies lower than 1MHz; and Auroral medium frequency (MF) burst, broadband impulsive radio emissions observed at ground level during the breakup phase of auroral substorms. High resolution broad band structure of those three emissions are recorded automatically at South Pole, and are crucial to our understanding the mechanism and relations of auroral radio emissions. This experiment uses a 3×3 meter square magnetic dipole antenna, located 1.7 km away from the South Pole station. A pre-amplifier is buried right below the eastern pylon of the antenna, connected by a 1.7 km long co-axial cable to a LF-HF receiver in the station. The output of the receiver is fed into the Versatile Electromagnetic Wave Receiver (VIEW) and Windows system equipped with a digitization board. Customed software was used to digitize the selected signals at 1-2 MHz. This data acquisition system was designed so that researchers at Dartmouth College can review the data from South Pole weekly and save interesting parts according to instructions sent from Dartmouth. In the year of 2004(from Jan through September), the experiment concentrated on the auroral hiss frequency band, covering either 0-500 kHz or 0-1000 kHz. With 3-6 hours window per day, VIEW captured more than 30 GBytes data of auroral hiss waveforms. Many experiments report wave forms of VLF auroral hiss at f < 30 kHz. We focused on waveforms of LF auroral hiss, typically at 100-300 kHz. At these frequencies, the hiss shows striking fine structure. We classified our LF hiss events into three different types: standard

  13. HIGH RESOLUTION EMITTANCE MEASUREMENTS AT SNS FRONT END

    SciTech Connect

    Aleksandrov, Alexander V; Zhukov, Alexander P

    2013-01-01

    The Spallation Neutron Source (SNS) linac accelerates an H- beam from 2.5MeV up to 1GeV. Recently the emittance scanner in the MEBT (2.5 MeV) was upgraded. In addition to the slit - harp measurement, we now can use a slit installed on the same actuator as the harp. In combination with a faraday cup located downstream in DTL part of the linac, it represents a classical slit-slit emittance measurement device. While a slit slit scan takes much longer, it is immune to harp related problems such as wire cross talk, and thus looks promising for accurate halo measurements. Time resolution of the new device seems to be sufficient to estimate the amount of beam in the chopper gap (the scanner is downstream of the chopper), and probably to measure its emittance. This paper describes the initial measurements with the new device and some model validation data.

  14. High-Resolution Parallax Measurements of Scorpius X-1

    NASA Astrophysics Data System (ADS)

    Bradshaw, C. F.; Fomalont, E. B.; Geldzahler, B. J.

    1999-02-01

    The results of eight VLBA observations at 5 GHz, spanning 3 yr, have yielded a measured trigonometric parallax for Sco X-1 of 0.00036"+/-0.00004" hence, its distance is 2.8+/-0.3 kpc. This is the most precise parallax measured to date. Although our measured distance is 40% farther away than previous estimates based on X-ray luminosity, our Rossi X-Ray Timing Explorer observations, with a measured luminosity of 2.3×1038 ergs s-1, and determined distance continue to support the hypothesis that Z-source low-mass X-ray binary systems, like Sco X-1, radiate at the Eddington luminosity at a particular point in their X-ray color-color diagram.

  15. The High Resolution Measurement of P and S Velocity

    NASA Astrophysics Data System (ADS)

    Kobayashi, T.; Azuma, H.

    2013-12-01

    Seismic explorations, which give seismic velocity, such as seismic refraction method and the down hole - PS logging, are generally applied to the large - scale area. Typically, at these seismic explorations, the receivers spacing ranges from 1.0m to 20.0m and resolution which means a minimal area required to determine seismic velocity is 10 to 50m depending of the receivers spacing. On the other hand, recently, seismic exploration to the smaller area has been applied with increasing frequency. For the large-scale constructions which require severe safety, such as the power station, dam, tunnels, bridges, the rock physical properties in wide area of several hundred meter square, are necessary in order to assess the safety when those are built and an earthquake comes. However, field tests which give the physical properties are almost applied to the area of around 1 m square. In this case, the issue exists whether or not the small field test area is representative of the whole rock property in the site. For this issue, seismic explorations to the small area are adopted for the purpose of the comparison between seismic velocity in the field test area and in the whole site area. It is generally recognized that the accuracy of seismic velocity decrease with decreasing seismic measurement length and number of receivers. To achieve high accuracy with the seismic exploration to the smaller area, we should adjust the spacing closer between the receivers compared to the spacing used by the existing method, and increase the number of receivers. And also, by doing this, we can increase the resolution of velocity results. At first, before the investigation, we calculated the errors of velocity caused by picking error of the arrival time from slope of a straight line using the linear least squares method, based on the Theory of Errors. This method shows that we should use the high frequency seismic wave in order to achieve the increasing the accuracy with the short seismic

  16. High resolution wind measurements for offshore wind energy development

    NASA Technical Reports Server (NTRS)

    Nghiem, Son Van (Inventor); Neumann, Gregory (Inventor)

    2013-01-01

    A method, apparatus, system, article of manufacture, and computer readable storage medium provide the ability to measure wind. Data at a first resolution (i.e., low resolution data) is collected by a satellite scatterometer. Thin slices of the data are determined. A collocation of the data slices are determined at each grid cell center to obtain ensembles of collocated data slices. Each ensemble of collocated data slices is decomposed into a mean part and a fluctuating part. The data is reconstructed at a second resolution from the mean part and a residue of the fluctuating part. A wind measurement is determined from the data at the second resolution using a wind model function. A description of the wind measurement is output.

  17. High Resolution Spectral Measurements of Electrical Propulsion Plasmas

    NASA Astrophysics Data System (ADS)

    Celik, Murat; Batishchev, Oleg; Martinez-Sanchez, Manuel

    2007-11-01

    Among various diagnostics methods in studying the EP thrusters' plasma, emission spectroscopy provides a non-invasive, fast and economical diagnostics allowing also the ability to access hard to reach locations. This study presents the spectral measurement results of SPT (BHT-200) and TAL (MHT-9) Hall Effect thrusters and mini-Helicon (mHTX@MIT) thruster plasmas. The measurements were conducted using a 750mm focal length spectrometer with a spectral resolution of up to ˜0.01 nm in the UV-VIS-NIR wavelength range, 200-1000nm. For one set of the measurements, collection optics was placed on a portable optical shelf attached to the window port of the vacuum chamber. For another set of measurements the thruster plasma radiation emission was collected using a collimating lens inside the vacuum chamber and the signal was brought out of the chamber to the spectrometer by the use of UV-rated optical fibers. Accurate spectral characterization was done for Xe and Ar plasma in a broad operational range. Additionally, emission spectroscopy was used to detect line radiation due to wall erosion products in SPT, to study the effect of thruster operational parameters on the ceramic lining erosion rate, subsequently of the thruster's lifetime.

  18. High resolution redox potential measurements: techniques, interpretation and value

    NASA Astrophysics Data System (ADS)

    Vorenhout, Michel; van der Geest, Harm G.

    2013-04-01

    The ongoing improvement of techniques for the in situ measurement of redox potentials has led to a large number of studies on redox variability in various environments. These studies originate from a wide array of scientific disciplines, amongst which ecology (sediment biogeochemistry), environmental chemistry (degradation studies) and archaeology (in situ preservation). To gain insight in the potential applications, this paper presents three examples of studies in which a newly developed measurement technique was used in soils and where spatial and temporal variation plays an important role. The first one is a microcosm study on the effects of biota on the dynamics of redox conditions in the toplayer of aquatic sediments, showing that the presence of microbiota has a direct influence on biogeochemical parameters. The second is the study of the redox potential in the world heritage site of Bryggen (Bergen, NO) that is under threat of oxidation. The oxidation, caused by a lowered groundwater table, causes soil degradation and unstable conditions for the monumental buildings of the Medieval site. The third study shows variability in a sandy flood plain in Bangladesh, where redox processes dictate the environmental behaviour of Arsenic. This toxic metal is present in many wells used for drinking water, but shows very local variation in dissolution dynamics. In these three studies, continuous measurements of (changes in) redox conditions revealed a strong variability in these systems and consequences for the interpretation of single point measurements or low frequency sampling campaigns are discussed. In these and many other cases, the continuous measurement of the redox potential in soil media will aid in the understanding of the system under study.

  19. High resolution DNA content measurements of mammalian sperm

    SciTech Connect

    Pinkel, D.; Lake, S.; Gledhill, B.L.; Van Dilla, M.A.; Stephenson, D.; Watchmaker, G.

    1982-01-01

    The high condensation and flat shape of the mammalian sperm nucleus present unique difficulties to flow cytometric measurement of DNA content. Chromatin compactness makes quantitative fluorescent staining for DNA difficult and causes a high index of refraction. The refractive index makes optical measurements sensitive to sperm head orientation. We demonstrate that the optical problems can be overcome using the commercial ICP22 epiillumination flow cytometer (Ortho Instruments, Westwood, MA) or a specially built cell orientating flow cytometer (OFCM). The design and operation of the OFCM are described. Measurements of the angular dependence of fluorescence from acriflavine stained rabbit sperm show that it is capable of orienting flat sperm with a tolerance of +-7/sup 0/. Differences in the angular dependence for the similarly shaped bull and rabbit sperm allow discrimination of these cells. We show that DNA staining with 4-6 diamidino-2-phenylindole (DAPI) or an ethidium bromide mithramycin combination allows resolution of the X and Y populations in mouse sperm. They have also been successful with sperm from the bull, ram, rabbit, and boar. Reliable results with human sperm are not obtained. The accuracy of the staining and measurement techniques are verified by the correct determination of the relative content of these two populations in sperm from normal mice and those with the Cattanach (7 to X) translocation. Among the potential uses of these techniques are measurement of DNA content errors induced in sperm due to mutagen exposure, and assessment of the fractions of X and Y sperm in semen that may have one population artifically enriched.

  20. High Resolution Viscosity Measurement by Thermal Noise Detection

    PubMed Central

    Aguilar Sandoval, Felipe; Sepúlveda, Manuel; Bellon, Ludovic; Melo, Francisco

    2015-01-01

    An interferometric method is implemented in order to accurately assess the thermal fluctuations of a micro-cantilever sensor in liquid environments. The power spectrum density (PSD) of thermal fluctuations together with Sader’s model of the cantilever allow for the indirect measurement of the liquid viscosity with good accuracy. The good quality of the deflection signal and the characteristic low noise of the instrument allow for the detection and corrections of drawbacks due to both the cantilever shape irregularities and the uncertainties on the position of the laser spot at the fluctuating end of the cantilever. Variation of viscosity below 0.03 mPa·s was detected with the alternative to achieve measurements with a volume as low as 50 μL. PMID:26540061

  1. High Resolution Viscosity Measurement by Thermal Noise Detection.

    PubMed

    Sandoval, Felipe Aguilar; Sepúlveda, Manuel; Bellon, Ludovic; Melo, Francisco

    2015-01-01

    An interferometric method is implemented in order to accurately assess the thermal fluctuations of a micro-cantilever sensor in liquid environments. The power spectrum density (PSD) of thermal fluctuations together with Sader's model of the cantilever allow for the indirect measurement of the liquid viscosity with good accuracy. The good quality of the deflection signal and the characteristic low noise of the instrument allow for the detection and corrections of drawbacks due to both the cantilever shape irregularities and the uncertainties on the position of the laser spot at the fluctuating end of the cantilever. Variation of viscosity below 0:03mPa·s was detected with the alternative to achieve measurements with a volume as low as 50 µL. PMID:26540061

  2. Toroidal magnetic detector for high resolution measurement of muon momenta

    DOEpatents

    Bonanos, Peter

    1992-01-01

    A muon detector system including central and end air-core superconducting toroids and muon detectors enclosing a central calorimeter/detector. Muon detectors are positioned outside of toroids and all muon trajectory measurements are made in a nonmagnetic environment. Internal support for each magnet structure is provided by sheets, located at frequent and regularly spaced azimuthal planes, which interconnect the structural walls of the toroidal magnets. In a preferred embodiment, the shape of the toroidal magnet volume is adjusted to provide constant resolution over a wide range of rapidity.

  3. Toroidal magnetic detector for high resolution measurement of muon momenta

    DOEpatents

    Bonanos, P.

    1992-01-07

    A muon detector system including central and end air-core superconducting toroids and muon detectors enclosing a central calorimeter/detector. Muon detectors are positioned outside of toroids and all muon trajectory measurements are made in a nonmagnetic environment. Internal support for each magnet structure is provided by sheets, located at frequent and regularly spaced azimuthal planes, which interconnect the structural walls of the toroidal magnets. In a preferred embodiment, the shape of the toroidal magnet volume is adjusted to provide constant resolution over a wide range of rapidity. 4 figs.

  4. High-resolution measurements of pressure solution creep.

    PubMed

    Dysthe, Dag Kristian; Renard, Francois; Feder, Jens; Jamtveit, Bjørn; Meakin, Paul; Jøssang, Torstein

    2003-07-01

    Two dilatometers with high precision and stability have been developed for measurement of indentation by pressure solution creep. The indentation of gold wires or glass cylinders into sodium chloride has been measured with down to 10 A accuracy and 6% precision. The indentation curves show a strong history dependence and the indentation rate decreases by three orders of magnitude over 400 h. The indentation mechanism is shown to be a pressure solution creep process in which material is dissolved at the indentor-sodium chloride contacts and transported to the free surface, where it precipitates in the proximity of the indentors. The indentation rates are not controlled by precipitation rates, the density of preexisting dislocations in the material, by change in the contact widths, or by ordinary plastic deformation. Small amplitude sinusoidal variations of temperature and normal stress are shown to have a large effect on the indentation rate. Moreover, sudden increase in normal stress from the indentor on the sodium chloride is shown to initiate an increased, time-dependent indentation rate. A model for pressure solution creep with time-dependent contact sizes explains the history dependence of the indentation data presented. PMID:12935153

  5. Note: A new angle-resolved proton energy spectrometer

    SciTech Connect

    Zheng, Y.; Su, L. N.; Liu, M.; Liu, B. C.; Shen, Z. W.; Fan, H. T.; Li, Y. T.; Chen, L. M.; Lu, X.; Ma, J. L.; Wang, W. M.; Wang, Z. H.; Wei, Z. Y.; Zhang, J.

    2013-09-15

    In typical laser-driven proton acceleration experiments Thomson parabola proton spectrometers are used to measure the proton spectra with very small acceptance angle in specific directions. Stacks composed of CR-39 nuclear track detectors, imaging plates, or radiochromic films are used to measure the angular distributions of the proton beams, respectively. In this paper, a new proton spectrometer, which can measure the spectra and angular distributions simultaneously, has been designed. Proton acceleration experiments performed on the Xtreme light III laser system demonstrates that the spectrometer can give angle-resolved spectra with a large acceptance angle. This will be conductive to revealing the acceleration mechanisms, optimization, and applications of laser-driven proton beams.

  6. Momentum and Doping Dependent Gap Dynamics of Bi2 Sr2 CaCu2 O8 + d studied by Time and Angle Resolved Photoemission

    NASA Astrophysics Data System (ADS)

    Ma, Jonathan Han Son; Miller, Tristan; Zhang, Wen Tao; Kurashima, Koshi; Eisaki, Hiroshi; Lanzara, Alessandra

    Dynamics of the superconducting gap and pseudogap can be induced by laser pumping and such dynamics may reveal critical clues for the underlying mechanism behind their formation and possibly the origin of superconductivity in cuprate superconductors. Here we report ultra-fast and ultra-high resolution time resolved angle-resolved photoemission (tr-ARPES) measurements in double layer Bi2Sr2CaCu2O8 both as a function of doping and excitation density. The momentum dependent behavior of the gap dynamics and quasiparticle recombination will be discussed.

  7. Angle resolved electron energy loss spectroscopy on graphite

    NASA Astrophysics Data System (ADS)

    Diebold, U.; Preisinger, A.; Schattschneider, P.; Varga, P.

    We report on angle resolved electron energy loss spectroscopy (EELS) in reflection mode with low primary energy on a graphite single crystal. Measurements with primary electron energy of 175 eV have been performed in off-Bragg-reflex geometry in two different directions within the (0001) surface plane of the graphite single crystal. In addition, EELS measurements in specular reflection mode with different primary energies and angles of incidence were done in order to distinguish between surface and bulk plasmon losses. The energy losses and the transferred momenta of the losses have been analyzed. The results are compared with the loss functions for bulk and surface excitations calculated from the dielectric function ɛ(ω, q) obtained from TEELS-data (EELS in transmission mode) [Springer Tracts Mod. Phys. 54 (1970) 77].

  8. Resolution-Tunable Angle-Resolved X-ray Imaging

    SciTech Connect

    Hirano, Keiichi

    2004-05-12

    A resolution-tunable double-crystal device was successfully applied to angle-resolved x-ray imaging. The angular resolution of a Si (220) double-crystal analyzer was tuned between 0.5'' and 2.3'' through the offset angle at {lambda} = 0.0733nm. The throughput of the analyzer was higher than 90%. The angle-resolved images of a spider were recorded on nuclear emulsion plates at various angular resolutions. It was clearly observed that the quality of the angle-resolved image varies with the angular resolution of the analyzer.

  9. Tachometer Derived From Brushless Shaft-Angle Resolver

    NASA Technical Reports Server (NTRS)

    Howard, David E.; Smith, Dennis A.

    1995-01-01

    Tachometer circuit operates in conjunction with brushless shaft-angle resolver. By performing sequence of straightforward mathematical operations on resolver signals and utilizing simple trigonometric identity, generates voltage proportional to rate of rotation of shaft. One advantage is use of brushless shaft-angle resolver as main source of rate signal: no brushes to wear out, no brush noise, and brushless resolvers have proven robustness. No switching of signals to generate noise. Another advantage, shaft-angle resolver used as shaft-angle sensor, tachometer input obtained without adding another sensor. Present circuit reduces overall size, weight, and cost of tachometer.

  10. Angle-resolved photoemission studies of the valence bands of ZrSxSe2-x

    NASA Astrophysics Data System (ADS)

    Moustafa, Mohamed; Paulheim, Alexander; Mohamed, Mansour; Janowitz, Christoph; Manzke, Recardo

    2016-03-01

    The electronic structure of the ternary layered transition metal dichalcogenide compounds of ZrSxSe2-x, where 0 ≤ x ≤ 2, has been studied by means of high resolution angle-resolved photoemission spectroscopy (ARPES) used in conjunction with synchrotron radiation facilities. The crystals were grown by the chemical vapor transport technique using iodine as a transport agent. They are found to be degenerate extrinsic n-type semiconductors with an indirect bandgap character. The experimental valence band structure of the complete series of ZrSxSe2-x is reported along the major symmetry azimuthal directions in the Brillouin zone parallel to the layers. The results show that the binding energies of the topmost valence band shift almost linearly with the composition parameter x. Further, an emission from the conduction band minimum observed just below the Fermi edge enabled us to estimate the energy gap values. The electronic structure deduced from the photoemission measurements are discussed and compared to band structure calculations.

  11. [Measurement of OH radicals in flame with high resolution differential optical absorption spectroscopy].

    PubMed

    Liu, Yu; Liu, Wen-Qing; Kan, Rui-Feng; Si, Fu-Qi; Xu, Zhen-Yu; Hu, Ren-Zhi; Xie, Pin-Hua

    2011-10-01

    The present paper describes a new developed high resolution differential optical absorption spectroscopy instrument used for the measurement of OH radicals in flame. The instrument consists of a Xenon lamp for light source; a double pass high resolution echelle spectrometer with a resolution of 3.3 pm; a multiple-reflection cell of 20 meter base length, in which the light reflects in the cell for 176 times, so the whole path length of light can achieve 3 520 meters. The OH radicals'6 absorption lines around 308 nm were simultaneously observed in the experiment. By using high resolution DOAS technology, the OH radicals in candles, kerosene lamp, and alcohol burner flames were monitored, and their concentrations were also inverted. PMID:22250529

  12. Developing High-Resolution Inundation Estimates through a Downscaling of Brightness Temperature Measurements

    NASA Astrophysics Data System (ADS)

    Fisher, C. K.; Wood, E. F.

    2014-12-01

    There is currently a large demand for high-resolution estimates of inundation extent and flooding for applications in water management, risk assessment and hydrologic modeling. In many regions of the world it is possible to examine the extent of past inundation from visible and infrared imagery provided by sensors such as the Moderate Resolution Imaging Spectroradiometer (MODIS); however, this is not possible in regions that are densely vegetated or are under persistent cloud cover. As a result of this, there is a need for alternative methodologies that make use of other remotely sensed data sources to inform high-resolution estimates of inundation. One such data source is the AMSR-E/Aqua 37 GHz vertically and horizontally polarized brightness temperature measurements, which have been used in previous studies to estimate the extent of inundated areas and which can make observations in vegetated or cloudy regions. The objective of this work was to develop a decision tree classifier based downscaling methodology by which inundation extent can be obtained at a high resolution, based on microwave brightness temperature measurements and high resolution topographic information. Using a random forest classifier that combined the AMSR-E 37GHz brightness temperatures (~12km mean spatial resolution) and a number of high-resolution topographic indices derived from the National Elevation Dataset for the United States (30m spatial resolution), a high-resolution estimate of inundation was created. A case study of this work is presented for the severe flooding that occurred in Iowa during the summer of 2008. Training and validation data for the random forest classifier were derived from an ensemble of previously existing estimates of inundation from sources such as MODIS imagery, as well as simulated inundation extents generated from a hydrologic routing model. Results of this work suggest that the decision tree based downscaling has skill in producing high-resolution estimates

  13. High-resolution setup for measuring wavelength sensitivity of photoyellowing of translucent materials

    SciTech Connect

    Vaskuri, Anna Kärhä, Petri; Heikkilä, Anu

    2015-10-15

    Polystyrene and many other materials turn yellow when exposed to ultraviolet (UV) radiation. All photodegradation mechanisms including photoyellowing are functions of the exposure wavelength, which can be described with an action spectrum. In this work, a new high-resolution transmittance measurement setup based on lasers has been developed for measuring color changes, such as the photoyellowing of translucent materials aged with a spectrograph. The measurement setup includes 14 power-stabilized laser lines between 325 nm and 933 nm wavelengths, of which one at a time is directed on to the aged sample. The power transmitted through the sample is measured with a silicon detector utilizing an integrating sphere. The sample is mounted on a high-resolution XY translation stage. Measurement at various locations aged with different wavelengths of exposure radiation gives the transmittance data required for acquiring the action spectrum. The combination of a UV spectrograph and the new high-resolution transmittance measurement setup enables a novel method for studying the UV-induced ageing of translucent materials with a spectral resolution of 3–8 nm, limited by the adjustable spectral bandwidth range of the spectrograph. These achievements form a significant improvement over earlier methods.

  14. High-resolution setup for measuring wavelength sensitivity of photoyellowing of translucent materials

    NASA Astrophysics Data System (ADS)

    Vaskuri, Anna; Kärhä, Petri; Heikkilä, Anu; Ikonen, Erkki

    2015-10-01

    Polystyrene and many other materials turn yellow when exposed to ultraviolet (UV) radiation. All photodegradation mechanisms including photoyellowing are functions of the exposure wavelength, which can be described with an action spectrum. In this work, a new high-resolution transmittance measurement setup based on lasers has been developed for measuring color changes, such as the photoyellowing of translucent materials aged with a spectrograph. The measurement setup includes 14 power-stabilized laser lines between 325 nm and 933 nm wavelengths, of which one at a time is directed on to the aged sample. The power transmitted through the sample is measured with a silicon detector utilizing an integrating sphere. The sample is mounted on a high-resolution XY translation stage. Measurement at various locations aged with different wavelengths of exposure radiation gives the transmittance data required for acquiring the action spectrum. The combination of a UV spectrograph and the new high-resolution transmittance measurement setup enables a novel method for studying the UV-induced ageing of translucent materials with a spectral resolution of 3-8 nm, limited by the adjustable spectral bandwidth range of the spectrograph. These achievements form a significant improvement over earlier methods.

  15. Experimental measurement of human head motion for high-resolution computed tomography system design

    NASA Astrophysics Data System (ADS)

    Li, Liang; Chen, Zhiqiang; Jin, Xin; Yu, Hengyong; Wang, Ge

    2010-06-01

    Human head motion has been experimentally measured for high-resolution computed tomography (CT) design using a Canon digital camera. Our goal is to identify the minimal movements of the human head under ideal conditions without rigid fixation. In our experiments, all the 19 healthy volunteers were lying down with strict self-control. All of them were asked to be calm without pressures. Our results showed that the mean absolute value of the measured translation excursion was about 0.35 mm, which was much less than the measurements on real patients. Furthermore, the head motions in different directions were correlated. These results are useful for the design of the new instant CT system for in vivo high-resolution imaging (about 40 μm).

  16. High-resolution compact shear stress sensor for direct measurement of skin friction in fluid flow

    NASA Astrophysics Data System (ADS)

    Xu, Muchen; Kim, Chang-Jin ``Cj''

    2015-11-01

    The high-resolution measurement of skin friction in complex flows has long been of great interest but also a challenge in fluid mechanics. Compared with indirect measurement methods (e.g., laser Doppler velocimetry), direct measurement methods (e.g., floating element) do not involve any analogy and assumption but tend to suffer from instrumentation challenges, such as low sensing resolution or misalignments. Recently, silicon micromachined floating plates showed good resolution and perfect alignment but were too small for general purposes and too fragile to attach other surface samples repeatedly. In this work, we report a skin friction sensor consisting of a monolithic floating plate and a high-resolution optical encoder to measure its displacement. The key for the high resolution is in the suspension beams, which are very narrow (e.g., 0.25 mm) to sense small frictions along the flow direction but thick (e.g., 5 mm) to be robust along all other directions. This compact, low profile, and complete sensor is easy to use and allows repeated attachment and detachment of surface samples. The sheer-stress sensor has been tested in water tunnel and towing tank at different flow conditions, showing high sensing resolution for skin friction measurement. Supported by National Science Foundation (NSF) (No. 1336966) and Defense Advanced Research Projects Agency (DARPA) (No. HR0011-15-2-0021).

  17. Measurement of high-resolution mechanical contraction of cardiac muscle by induced eddy current.

    PubMed

    Lee, Young-Jae; Lee, Kang-Hwi; Kang, Seung-Jin; Kim, Kyeung-Nam; Khang, Seonah; Koo, Hye Ran; Gi, Sunok; Lee, Joo Hyeon; Lee, Jeong-Whan

    2014-01-01

    There are many types of devices which help to manage a personal health conditions such as heartbeat chest belt, pedometer and smart watch. And the most common device has the relationship with heart rate or ECG data. However, users have to attach some electrode or fasten the belt on the bare skin to measure bio-signal information. Therefore, most of people want more convenient and short-ready-time and no-need to attach electrode. In this paper, we proposed the high-resolution measuring system of mechanical activity of cardiac muscle and thereby measure heartbeat. The principle of the proposed measuring method is that the alternating current generate alternating magnetic field around coil. This primary magnetic field induces eddy current which makes magnetic field against primary coil in the nearby objects. To measure high-resolution changes of the induced secondary magnetic fields, we used digital Phase-locked loop(PLL) circuit which provides more high-resolution traces of frequency changes than the previous studies based on digital frequency counter method. As a result of our preliminary experiment, peak-peak intervals of the proposed method showed high correlation with R-R intervals of clinical ECG signals(r=0.9249). Also, from signal traces of the proposed method, we might make a conjecture that the contraction of atrium or ventricle is reflected by changing conductivity of cardiac muscle which is beating ceaselessly. PMID:25571434

  18. High resolution frequency to time domain transformations applied to the stepped carrier MRIS measurements

    NASA Technical Reports Server (NTRS)

    Ardalan, Sasan H.

    1992-01-01

    Two narrow-band radar systems are developed for high resolution target range estimation in inhomogeneous media. They are reformulations of two presently existing systems such that high resolution target range estimates may be achieved despite the use of narrow bandwidth radar pulses. A double sideband suppressed carrier radar technique originally derived in 1962, and later abandoned due to its inability to accurately measure target range in the presence of an interfering reflection, is rederived to incorporate the presence of an interfering reflection. The new derivation shows that the interfering reflection causes a period perturbation in the measured phase response. A high resolution spectral estimation technique is used to extract the period of this perturbation leading to accurate target range estimates independent of the signal-to-interference ratio. A non-linear optimal signal processing algorithm is derived for a frequency-stepped continuous wave radar system. The resolution enhancement offered by optimal signal processing of the data over the conventional Fourier Transform technique is clearly demonstrated using measured radar data. A method for modeling plane wave propagation in inhomogeneous media based on transmission line theory is derived and studied. Several simulation results including measurement of non-uniform electron plasma densities that develop near the heat tiles of a space re-entry vehicle are presented which verify the validity of the model.

  19. High-Resolution UV Holography Lens for Particle Size Distribution Measurements

    SciTech Connect

    Malone, Morris Kaufman; Capelle, Gene; Grover, Mike; Sorenson, Dan; Pazuchanics, Pete

    2010-01-01

    A high-resolution UV holography relay lens, shown in Figure 1, has been developed for measuring particle size distributions down to 0.5 μm in a 12-mm-diameter by 5-mm-thick volume. This work has been selected by an independent judging panel and editors of R&D Magazine as a recipient of a 2009 R&D 100 Award. This award recognizes the 100 most technologically significant products introduced during the past year.

  20. High resolution ion mobility measurements of peptides, proteins, and atomic clusters

    NASA Astrophysics Data System (ADS)

    Hudgins, Robert Ransone

    1999-12-01

    A novel high resolution ion mobility apparatus has been constructed and applied to the study of atomic clusters and biological molecules in the gas phase. The resolving power of the high resolution apparatus is over an order of magnitude higher than has been achieved using conventional injected-ion drift tube techniques. A number of advantages of the experimental configuration, in addition to the higher resolution, are described. High resolution ion mobility measurements have been performed on atomic clusters of various composition. Several isomers for carbon cluster anions have been resolved for the first time. By comparison to computationally derived structures, detailed structural information can be extracted from the measurements. For small carbon cluster anions, ``tadpole'' isomers, where a short carbon chain is attached to a carbon ring, have been identified. Mobility measurements for (NaCl)nCl- clusters have revealed multiple isomers with the same fcc packing but different j x k x l dimensions. Metastable (NaCl)nCl- geometries isomerize on the timescale of the mobility measurements (hundreds of milliseconds). Rate constants and activation energies for the isomerization processes are extracted directly from the mobility measurements; the activation energies are found to be remarkably low. Indium and silicon cluster mobilities are found to be sensitive to the degree of electron spillout from the surface of the cluster, as revealed in differences in the anionic and cationic cluster mobilities. Mobility measurements of solvent-free biological molecules reveal important information about their intramolecular forces. Due to the gentle ion sampling in the high resolution ion mobility apparatus electrospray interface, high resolution mobilities of gas-phase proteins are found to be sensitive to the nature of the electrosprayed solution. Although calculations have shown that neutral polyalanine in vacuo is mostly helical, gas- phase polyalanine ions, AnH+, are found

  1. A sensitive, high resolution magic angle turning experiment for measuring chemical shift tensor principal values

    NASA Astrophysics Data System (ADS)

    Alderman, D. W.

    1998-12-01

    A sensitive, high-resolution 'FIREMAT' two-dimensional (2D) magic-angle-turning experiment is described that measures chemical shift tensor principal values in powdered solids. The spectra display spinning-sideband patterns separated by their isotropic shifts. The new method's sensitivity and high resolution in the isotropic-shift dimension result from combining the 5pi magic-angle-turning pulse sequence, an extension of the pseudo-2D sideband-suppression data rearrangement, and the TIGER protocol for processing 2D data. TPPM decoupling is used to enhance resolution. The method requires precise synchronization of the pulses and sampling to the rotor position. It is shown that the technique obtains 35 natural-abundance 13C tensors from erythromycin in 19 hours, and high quality naturalabundance 15N tensors from eight sites in potassium penicillin V in three days on a 400MHz spectrometer.

  2. Bacteriorhodopsin as a high-resolution, high-capacity buffer for digital holographic measurements

    NASA Astrophysics Data System (ADS)

    Barnhart, D. H.; Koek, W. D.; Juchem, T.; Hampp, N.; Coupland, J. M.; Halliwell, N. A.

    2004-04-01

    Recent trends in optical metrology suggest that, in order for holographic measurement to become a widespread tool, it must be based on methods that do not require physical development of the hologram. While digital holography has been successfully demonstrated in recent years, unfortunately the limited information capacity of present electronic sensors, such as CCD arrays, is still many orders of magnitude away from directly competing with the high-resolution silver halide plates used in traditional holography. As a result, present digital holographic methods with current electronic sensors cannot record object sizes larger than several hundred microns at high resolution. In this paper, the authors report on the use of bacteriorhodopsin (BR) for digital holography to overcome these limitations. In particular, BR is a real-time recording medium with an information capacity (5000 line-pairs/mm) that even exceeds high resolution photographic film. As such, a centimetre-square area of BR film has the same information capacity of several hundred state-of-the-art CCD cameras. For digital holography, BR temporarily holds the hologram record so that its information content can be digitized for numeric reconstruction. In addition, this paper examines the use of BR for optical reconstruction without chemical development. When correctly managed, it is found that BR is highly effective, in terms of both quality and process time, for three-dimensional holographic measurements. Consequently, several key holographic applications, based on BR, are proposed in this paper.

  3. High resolution magnetostriction measurements in pulsed magnetic fields using fiber Bragg gratings

    NASA Astrophysics Data System (ADS)

    Daou, Ramzy; Weickert, Franziska; Nicklas, Michael; Steglich, Frank; Haase, Ariane; Doerr, Mathias

    2010-03-01

    We report on a new high resolution apparatus for measuring magnetostriction suitable for use at cryogenic temperatures in pulsed high magnetic fields which we have developed at the Hochfeld-Magnetlabor Dresden. Optical fiber strain gauges based on fiber Bragg gratings are used to measure the strain in small (˜1 mm) samples. We describe the implementation of a fast measurement system capable of resolving strains in the order of 10-7 with a full bandwidth of 47 kHz, and demonstrate its use on single crystal samples of GdSb and GdSi.

  4. A model-based approach for the calibration and traceability of the angle resolved scattering light sensor

    NASA Astrophysics Data System (ADS)

    Seewig, Jörg; Eifler, Matthias; Schneider, Frank; Kirsch, Benjamin; Aurich, Jan C.

    2016-06-01

    Within the field of geometric product specification there is a growing need for the application of inline measurement systems. The use of inline measurement requires robust and fast measurement principles. A very robust optical measurement principle is the angle resolved scattering light (ARS) sensor. The ARS sensor provides high precision and high resolution measurement data of technical surfaces because the surface angles are measured as an intensity distribution on a detector instead of measuring a series of discrete height values. However, until now, there were no specific measurement standards for the calibration of the ARS sensor and no traceability was ensured. In this paper, new strategies for the calibration of an ARS sensor are proposed. A new mathematical model for the ARS sensor is introduced. Based on this, two new measurement standards for the calibration of the sensor parameters are derived. These standards are designed with a model-based approach and can calibrate sensor-specific properties of the ARS sensor. The manufacturing of the standards is described and measurement results are provided.

  5. High-Resolution Group Quantization Phase Processing Method in Radio Frequency Measurement Range

    NASA Astrophysics Data System (ADS)

    Du, Baoqing; Feng, Dazheng; Tang, Yaohua; Geng, Xin; Zhang, Duo; Cai, Chaofeng; Wan, Maoquan; Yang, Zhigang

    2016-07-01

    Aiming at the more complex frequency translation, the longer response time and the limited measurement precision in the traditional phase processing, a high-resolution phase processing method by group quantization higher than 100 fs level is proposed in radio frequency measurement range. First, the phase quantization is used as a step value to quantize every phase difference in a group by using the fixed phase relationships between different frequencies signals. The group quantization is formed by the results of the quantized phase difference. In the light of frequency drift mainly caused by phase noise of measurement device, a regular phase shift of the group quantization is produced, which results in the phase coincidence of two comparing signals which obtain high-resolution measurement. Second, in order to achieve the best coincidences pulse, a subtle delay is initiatively used to reduce the width of the coincidences fuzzy area according to the transmission characteristics of the coincidences in the specific medium. Third, a series of feature coincidences pulses of fuzzy area can be captured by logic gate to achieve the best phase coincidences information for the improvement of the measurement precision. The method provides a novel way to precise time and frequency measurement.

  6. High-Resolution Group Quantization Phase Processing Method in Radio Frequency Measurement Range

    PubMed Central

    Du, Baoqing; Feng, Dazheng; Tang, Yaohua; Geng, Xin; Zhang, Duo; Cai, Chaofeng; Wan, Maoquan; Yang, Zhigang

    2016-01-01

    Aiming at the more complex frequency translation, the longer response time and the limited measurement precision in the traditional phase processing, a high-resolution phase processing method by group quantization higher than 100 fs level is proposed in radio frequency measurement range. First, the phase quantization is used as a step value to quantize every phase difference in a group by using the fixed phase relationships between different frequencies signals. The group quantization is formed by the results of the quantized phase difference. In the light of frequency drift mainly caused by phase noise of measurement device, a regular phase shift of the group quantization is produced, which results in the phase coincidence of two comparing signals which obtain high-resolution measurement. Second, in order to achieve the best coincidences pulse, a subtle delay is initiatively used to reduce the width of the coincidences fuzzy area according to the transmission characteristics of the coincidences in the specific medium. Third, a series of feature coincidences pulses of fuzzy area can be captured by logic gate to achieve the best phase coincidences information for the improvement of the measurement precision. The method provides a novel way to precise time and frequency measurement. PMID:27388587

  7. High-Resolution Group Quantization Phase Processing Method in Radio Frequency Measurement Range.

    PubMed

    Du, Baoqing; Feng, Dazheng; Tang, Yaohua; Geng, Xin; Zhang, Duo; Cai, Chaofeng; Wan, Maoquan; Yang, Zhigang

    2016-01-01

    Aiming at the more complex frequency translation, the longer response time and the limited measurement precision in the traditional phase processing, a high-resolution phase processing method by group quantization higher than 100 fs level is proposed in radio frequency measurement range. First, the phase quantization is used as a step value to quantize every phase difference in a group by using the fixed phase relationships between different frequencies signals. The group quantization is formed by the results of the quantized phase difference. In the light of frequency drift mainly caused by phase noise of measurement device, a regular phase shift of the group quantization is produced, which results in the phase coincidence of two comparing signals which obtain high-resolution measurement. Second, in order to achieve the best coincidences pulse, a subtle delay is initiatively used to reduce the width of the coincidences fuzzy area according to the transmission characteristics of the coincidences in the specific medium. Third, a series of feature coincidences pulses of fuzzy area can be captured by logic gate to achieve the best phase coincidences information for the improvement of the measurement precision. The method provides a novel way to precise time and frequency measurement. PMID:27388587

  8. Technical note: quantitative measures of iris color using high resolution photographs.

    PubMed

    Edwards, Melissa; Gozdzik, Agnes; Ross, Kendra; Miles, Jon; Parra, Esteban J

    2012-01-01

    Our understanding of the genetic architecture of iris color is still limited. This is partly related to difficulties associated with obtaining quantitative measurements of eye color. Here we introduce a new automated method for measuring iris color using high resolution photographs. This method extracts color measurements in the CIE 1976 L*a*b* (CIELAB) color space from a 256 by 256 pixel square sampled from the 9:00 meridian of the iris. Color is defined across three dimensions: L* (the lightness coordinate), a* (the red-green coordinate), and b* (the blue-yellow coordinate). We applied this method to a sample of individuals of diverse ancestry (East Asian, European and South Asian) that was genotyped for the HERC2 rs12913832 polymorphism, which is strongly associated with blue eye color. We identified substantial variation in the CIELAB color space, not only in the European sample, but also in the East Asian and South Asian samples. As expected, rs12913832 was significantly associated with quantitative iris color measurements in subjects of European ancestry. However, this SNP was also strongly associated with iris color in the South Asian sample, although there were no participants with blue irides in this sample. The usefulness of this method is not restricted only to the study of iris pigmentation. High-resolution pictures of the iris will also make it possible to study the genetic variation involved in iris textural patterns, which show substantial heritability in human populations. PMID:22101828

  9. Precision angle-resolved autoionization resonances in Ar and Ne

    SciTech Connect

    Berrah, N.; Langer, B.; Gorczyca, T.W.

    1997-04-01

    Theoretical work has shown that the electron angular distribution and the shape of the autoionization resonances are crucial to the understanding of certain types of electron-electron correlation. Autoionization resonances in Ne (Ar) result from the decay of the excited discrete state Ne{sup *} 2s2p{sup 6} np (Ar{sup *} 3s3p{sup 6} np) into the continuum state Ne{sup +} 2s{sup 2}2p{sup 5} + e{sup {minus}} (ks,kd) (Ar{sup +} 3s{sup 2}3p{sup 5} + e{sup {minus}} (ks,kd)). Since the continuum can also be reached by direct photoionization, both paths add coherently, giving rise to interferences that produce the characteristic Beutler-Fano line shape. In this work, the authors report on quantitative angle-resolved electron spectrometry studies of (a) the Ne 2s{sup 2}2p{sup 6} {r_arrow} 2s2p{sup 6} np (n=3-5) autoionizing resonances and the 2s{sup 2}2p{sup 6} {r_arrow} 2p{sup 4}3s3p doubly excited resonance, (b) the Ar 3s{sup 2}3p{sup 6} {r_arrow} 3s3p{sup 6} np (n=4-9) autoionization resonances and extended R-matrix calculations of the angular-distribution parameters for both Ne and Ar measurements. Their results are compared with previous theoretical work by Taylor.

  10. A digitally configurable measurement platform using audio cards for high-resolution electronic transport studies.

    PubMed

    Gopman, D B; Bedau, D; Kent, A D

    2012-05-01

    We report on a software-defined digitally configurable measurement platform for determining electronic transport properties in nanostructures with small readout signals. By using a high-resolution audio analog-to-digital/digital-to-analog converter in a digitally compensated bridge configuration we significantly increase the measurement speed compared to established techniques and simultaneously acquire large and small signal characteristics. We characterize the performance (16 bit resolution, 100 dB dynamic range at 192 kS/s) and demonstrate the application of this measurement platform for studying the transport properties of spin-valve nanopillars, a two-terminal device that exhibits giant magnetoresistance and whose resistance can be switched between two levels by applied magnetic fields and by currents applied by the audio card. The high resolution and fast sampling capability permits rapid acquisition of deep statistics on the switching of a spin-valve nanopillar and reduces the time to acquire the basic properties of the device - a state-diagram showing the magnetic configurations as function of applied current and magnetic field - by orders of magnitude. PMID:22667635

  11. A digitally configurable measurement platform using audio cards for high-resolution electronic transport studies

    NASA Astrophysics Data System (ADS)

    Gopman, D. B.; Bedau, D.; Kent, A. D.

    2012-05-01

    We report on a software-defined digitally configurable measurement platform for determining electronic transport properties in nanostructures with small readout signals. By using a high-resolution audio analog-to-digital/digital-to-analog converter in a digitally compensated bridge configuration we significantly increase the measurement speed compared to established techniques and simultaneously acquire large and small signal characteristics. We characterize the performance (16 bit resolution, 100 dB dynamic range at 192 kS/s) and demonstrate the application of this measurement platform for studying the transport properties of spin-valve nanopillars, a two-terminal device that exhibits giant magnetoresistance and whose resistance can be switched between two levels by applied magnetic fields and by currents applied by the audio card. The high resolution and fast sampling capability permits rapid acquisition of deep statistics on the switching of a spin-valve nanopillar and reduces the time to acquire the basic properties of the device - a state-diagram showing the magnetic configurations as function of applied current and magnetic field - by orders of magnitude.

  12. High-resolution measurement of absolute {alpha}-decay widths in {sup 16}O

    SciTech Connect

    Wheldon, C.; Ashwood, N. I.; Barr, M.; Curtis, N.; Freer, M.; Kokalova, Tz.; Malcolm, J. D.; Spencer, S. J.; Ziman, V. A.; Faestermann, Th.; Kruecken, R.; Wirth, H.-F.; Hertenberger, R.; Lutter, R.; Bergmaier, A.

    2011-06-15

    By using a large-acceptance position-sensitive silicon detector array in coincidence with the high-resolution Munich Q3D spectrograph, unambiguous measurements have been made of the absolute {alpha}-particle decay widths from excited states in {sup 16}O* in the energy range 13.85 to 15.87 MeV. Carbon targets have been bombarded with 42-MeV {sup 6}Li beams to induce {sub 6}{sup 12}C({sub 3}{sup 6}Li, d){sub 8}{sup 16}O* reactions. The deuteron ejectiles were measured in the Q3D and the results gated by {sup 4}He+{sup 12}C breakup products detected in the silicon array, the efficiency of which was modeled using Monte Carlo simulations. By comparing total population and breakup-gated spectra, the following absolute {alpha}-decay widths have been measured with high resolution: {Gamma}{sub {alpha}}0/{Gamma}{sub tot} = 0.87{+-}0.11 (13.980 MeV), 1.04{+-}0.15 (14.302 MeV), 0.92{+-}0.10 (14.399 MeV), 0.59{+-}0.04 (14.815 MeV), 0.88{+-}0.18 (15.785 MeV), and {Gamma}{sub {alpha}}1/{Gamma}{sub tot}=1.14{+-}0.08 (14.660 MeV), 0.46{+-}0.06 (14.815 MeV).

  13. High-resolution laboratory measurements of coronal lines in the 198-218 å region

    SciTech Connect

    Beiersdorfer, Peter; Träbert, Elmar; Lepson, Jaan K.; Brickhouse, Nancy S.; Golub, Leon

    2014-06-10

    We present high-resolution laboratory measurements of the emission from various ions of C, N, O, F, Ne, S, Ar, Fe, and Ni in the extreme ultraviolet wavelength band centered around the λ211 Fe XIV channel of the Atmospheric Imaging Assembly on the Solar Dynamics Observatory. While all of the strong iron lines in this region are well known, we note many weaker lines of iron that are not yet identified. The high resolution of our measurements also allows us to resolve several lines in Fe XI, Fe XII, and Fe XIII between 200 and 205 Å, whose identities were in question based on a disagreement between different databases. The spectra of the elements other than iron are much less known, and we find a multitude of lines that are not yet in the databases. For example, the CHIANTI database clearly disagrees with the NIST data listings on several of the argon lines we observe and also it contains only about half of the observed sulfur lines.

  14. High-resolution spectroscopy used to measure inertial confinement fusion neutron spectra on Omega (invited).

    PubMed

    Forrest, C J; Radha, P B; Glebov, V Yu; Goncharov, V N; Knauer, J P; Pruyne, A; Romanofsky, M; Sangster, T C; Shoup, M J; Stoeckl, C; Casey, D T; Gatu-Johnson, M; Gardner, S

    2012-10-01

    The areal density (ρR) of cryogenic DT implosions on Omega is inferred by measuring the spectrum of neutrons that elastically scatter off the dense deuterium (D) and tritium (T) fuel. Neutron time-of-flight (nTOF) techniques are used to measure the energy spectrum with high resolution. High signal-to-background data has been recorded on cryogenic DT implosions using a well-collimated 13.4-m line of sight and an nTOF detector with an advanced liquid scintillator compound. An innovative method to analyze the elastically scattered neutron spectra was developed using well-known cross sections of the DT nuclear reactions. The estimated areal densities are consistent with alternative ρR measurements and 1-D simulations. PMID:23126921

  15. Comparison of HRDI wind measurements with radar and rocket observations. [High Resolution Doppler Imager

    NASA Technical Reports Server (NTRS)

    Burrage, M. D.; Skinner, W. R.; Marshall, A. R.; Hays, P. B.; Lieberman, R. S.; Franke, S. J.; Gell, D. A.; Ortland, D. A.; Morton, Y. T.; Schmidlin, F. J.

    1993-01-01

    Wind fields in the mesosphere and lower thermosphere are obtained with the High Resolution Doppler Imager (HRDI) on the Upper Atmosphere Research Satellite (UARS) by observing the Doppler shifts of emission lines in the O2 Atmospheric band. The validity of the measured winds depends on an accurate knowledge of the positions on the detector of the observed lines in the absence of a wind-induced Doppler shift. These positions have been determined to an accuracy of approximately 5 m/s from the comparison of winds measured by HRDI with those obtained by MF radars. Excellent agreement is found between HRDI measured winds and winds observed with radars and rockets. In addition, the sensitivity of HRDI to migrating tides and other large scale waves is demonstrated.

  16. Measurement of water content in polymer electrolyte membranes using high resolution neutron imaging

    SciTech Connect

    Spernjak, Dusan; Mukundan, Rangachary; Borup, Rodney L; Davey, John; Mukherjee, Partha P; Hussey, Daniel S; Jacobson, David

    2010-01-01

    Sufficient water content within a polymer electrolyte membrane (PEM) is necessary for adequate ionic conductivity. Membrane hydration is therefore a fundamental requirement for fuel cell operation. The hydration state of the membrane affects the water transport within, as both the diffusion coefficient and electro-osmotic drag depend on the water content. Membrane's water uptake is conventionally measured ex situ by weighing free-swelling samples equilibrated at controlled water activity. In the present study, water profiles in Nafion{reg_sign} membranes were measured using the high-resolution neutron imaging. The state-of-the-art, 10 {micro}m resolution neutron detector is capable of resolving water distributions across N1120, N1110 and N117 membranes. It provides a means to measure the water uptake and transport properties of fuel cell membranes in situ.

  17. PROBING NEAR-SURFACE ATMOSPHERIC TURBULENCE WITH LIDAR MEASUREMENTS AND HIGH-RESOLUTION HYDRODYNAMIC MODELS

    SciTech Connect

    J. KAO; D. COOPER; ET AL

    2000-11-01

    As lidar technology is able to provide fast data collection at a resolution of meters in an atmospheric volume, it is imperative to promote a modeling counterpart of the lidar capability. This paper describes an integrated capability based on data from a scanning water vapor lidar and a high-resolution hydrodynamic model (HIGRAD) equipped with a visualization routine (VIEWER) that simulates the lidar scanning. The purpose is to better understand the spatial and temporal representativeness of the lidar measurements and, in turn, to extend their utility in studying turbulence fields in the atmospheric boundary layer. Raman lidar water vapor data collected over the Pacific warm pool and the simulations with the HIGRAD code are used for identifying the underlying physics and potential aliasing effects of spatially resolved lidar measurements. This capability also helps improve the trade-off between spatial-temporal resolution and coverage of the lidar measurements.

  18. High-resolution spectroscopy used to measure inertial confinement fusion neutron spectra on Omega (invited)

    SciTech Connect

    Forrest, C. J.; Radha, P. B.; Glebov, V. Yu.; Goncharov, V. N.; Knauer, J. P.; Pruyne, A.; Romanofsky, M.; Sangster, T. C.; Shoup, M. J. III; Stoeckl, C.; Casey, D. T.; Gatu-Johnson, M.; Gardner, S.

    2012-10-15

    The areal density ({rho}R) of cryogenic DT implosions on Omega is inferred by measuring the spectrum of neutrons that elastically scatter off the dense deuterium (D) and tritium (T) fuel. Neutron time-of-flight (nTOF) techniques are used to measure the energy spectrum with high resolution. High signal-to-background data has been recorded on cryogenic DT implosions using a well-collimated 13.4-m line of sight and an nTOF detector with an advanced liquid scintillator compound. An innovative method to analyze the elastically scattered neutron spectra was developed using well-known cross sections of the DT nuclear reactions. The estimated areal densities are consistent with alternative {rho}R measurements and 1-D simulations.

  19. High Resolution Measurements In U-Channel Technique And Implications For Sedimentological Purposes

    NASA Astrophysics Data System (ADS)

    Acar, Dursun; Cagatay, Namık; Sarı, Erol; Eris, Kadir; Biltekin, Demet; Akcer, Sena; Meydan Gokdere, Feray; Makaroglu, Ozlem; Bulkan, Ozlem; Arslan, Tugce; Albut, Gulum; Yalamaz, Burak; Yakupoglu, Nurettin; Sabuncu, Asen; Fillikci, Betul; Yıldız, Guliz

    2016-04-01

    Mechanical features in-stu drilling for sediment cores and vacuum forces that affect while obtaining the sediments to the core tube are formed concave shaped deformations. Even in the half sections, concave deformation form still appears. During MCSL measurements, Laminae which forms concave shaped deformation, show interference thus, values indicate overall results for several laminae instead of single lamina. These interferenced data is not appropriate for paleoceanography studies which require extend accuracy and high frequency data set to describe geochemical and climatological effects in high resolution. U-Channel technique provides accurate location and isolated values for each lamina. In EMCOL Laboratories, U-channel provide well saturated and air-free environment for samples and, by using these technique U-channels are prepared with modificated MCSL for data acquisition. Even below millimeter scale sampling rate provides the separation of each lamina and, physical properties of every each lamina. Cover of u-channel is made by homogenous plastic in shape of rectangular prism geometry. Thus, during measurement, MSCL sensors may harm the sediment; however u-channel covers the sediment from this unwanted deformation from MSCL itself. U-channel technique can present micro scale angular changes in the laminae. Measurements that have been taken from U-channel are compared with the traditional half core measurements. Interestingly, accuracy of the positions for each lamina is much more detailed and, the resolution is progressively higher. Results from P Wave and Gamma ray density provide removed interference effects on each lamina. In this technique, it is high recommended that U-channel widens the resolution of core logging and generates more cleansed measurements in MCSL. For P- Wave Used Synthetic seismograms that modelled by MSCL data set which created from U-channel technique dictates each anomalies related with climatological and geological changes. Keywords

  20. High-resolution refractive index anisotropy measurement in optical fibers through phase retardation modulation

    NASA Astrophysics Data System (ADS)

    Sévigny, Benoit; Busque, François; Godbout, Nicolas; Lacroix, Suzanne; Faucher, Mathieu

    2008-03-01

    We present an improved, high-resolution method for the measurement of phase retardation induced by the material birefringence of optical fibers. Such a method can be used to retrieve information about the spatial distribution of refractive index anisotropy in the fiber by comparing the accumulated phase of a polarization component oriented along the fiber transmission axis and another located in the transverse plane. The method is based on the nonlinear regression of a phase modulated signal of known modulation amplitude altered by the sample. Experimental results obtained with our method for a standard telecommunications fiber (the Corning SMF-28) as well as photosensitive fibers (Fibercore PS1250 and PS1500) are presented with a noise-limited phase resolution below 10-4 radians and a spatial resolution below 1 μm. An analysis of the limitation of such measurement methods is also presented including diffraction by the fibers.

  1. High resolution gamma ray tomography scanner for flow measurement and non-destructive testing applications

    SciTech Connect

    Hampel, U.; Bieberle, A.; Hoppe, D.; Kronenberg, J.; Schleicher, E.; Suehnel, T.; Zimmermann, F.; Zippe, C.

    2007-10-15

    We report on the development of a high resolution gamma ray tomography scanner that is operated with a Cs-137 isotopic source at 662 keV gamma photon energy and achieves a spatial image resolution of 0.2 line pairs/mm at 10% modulation transfer function for noncollimated detectors. It is primarily intended for the scientific study of flow regimes and phase fraction distributions in fuel element assemblies, chemical reactors, pipelines, and hydrodynamic machines. Furthermore, it is applicable to nondestructive testing of larger radiologically dense objects. The radiation detector is based on advanced avalanche photodiode technology in conjunction with lutetium yttrium orthosilicate scintillation crystals. The detector arc comprises 320 single detector elements which are operated in pulse counting mode. For measurements at fixed vessels or plant components, we built a computed tomography scanner gantry that comprises rotational and translational stages, power supply via slip rings, and data communication to the measurement personal computer via wireless local area network.

  2. High resolution gamma ray tomography scanner for flow measurement and non-destructive testing applications

    NASA Astrophysics Data System (ADS)

    Hampel, U.; Bieberle, A.; Hoppe, D.; Kronenberg, J.; Schleicher, E.; Sühnel, T.; Zimmermann, F.; Zippe, C.

    2007-10-01

    We report on the development of a high resolution gamma ray tomography scanner that is operated with a Cs-137 isotopic source at 662keV gamma photon energy and achieves a spatial image resolution of 0.2linepairs/mm at 10% modulation transfer function for noncollimated detectors. It is primarily intended for the scientific study of flow regimes and phase fraction distributions in fuel element assemblies, chemical reactors, pipelines, and hydrodynamic machines. Furthermore, it is applicable to nondestructive testing of larger radiologically dense objects. The radiation detector is based on advanced avalanche photodiode technology in conjunction with lutetium yttrium orthosilicate scintillation crystals. The detector arc comprises 320 single detector elements which are operated in pulse counting mode. For measurements at fixed vessels or plant components, we built a computed tomography scanner gantry that comprises rotational and translational stages, power supply via slip rings, and data communication to the measurement personal computer via wireless local area network.

  3. High resolution measurements of galactic cosmic-ray neon, magnesium, and silicon isotopes

    NASA Technical Reports Server (NTRS)

    Mewaldt, R. A.; Spalding, J. D.; Stone, E. C.; Vogt, R. E.

    1980-01-01

    High-resolution measurements of the abundances of individual isotopes of neon, magnesium and silicon in galactic cosmic rays are reported. The Caltech Heavy Isotope Spectrometer Telescope on board the ISEE 3 spacecraft was used to obtain measurements in the range 30 to 180 MeV/n at an rms mass resolution of 0.20 amu. Results indicate excesses of Ne-22 as well as Mg-25 and Mg-26 in galactic cosmic rays with respect to their solar system abundances. Calculations of the effects of interstellar propagation and solar modulation on cosmic-ray isotope abundances also imply an Mg-25 + Mg-26 cosmic ray source fraction significantly greater than the solar system fraction, and it is suggested that the cosmic ray source material and solar system material were synthesized under different conditions.

  4. Angle-resolved Photoemission Spectroscopy At Ultra-low Temperatures

    PubMed Central

    Borisenko, Sergey V.; Zabolotnyy, Volodymyr B.; Kordyuk, Alexander A.; Evtushinsky, Danil V.; Kim, Timur K.; Carleschi, Emanuela; Doyle, Bryan P.; Fittipaldi, Rosalba; Cuoco, Mario; Vecchione, Antonio; Berger, Helmut

    2012-01-01

    The physical properties of a material are defined by its electronic structure. Electrons in solids are characterized by energy (ω) and momentum (k) and the probability to find them in a particular state with given ω and k is described by the spectral function A(k, ω). This function can be directly measured in an experiment based on the well-known photoelectric effect, for the explanation of which Albert Einstein received the Nobel Prize back in 1921. In the photoelectric effect the light shone on a surface ejects electrons from the material. According to Einstein, energy conservation allows one to determine the energy of an electron inside the sample, provided the energy of the light photon and kinetic energy of the outgoing photoelectron are known. Momentum conservation makes it also possible to estimate k relating it to the momentum of the photoelectron by measuring the angle at which the photoelectron left the surface. The modern version of this technique is called Angle-Resolved Photoemission Spectroscopy (ARPES) and exploits both conservation laws in order to determine the electronic structure, i.e. energy and momentum of electrons inside the solid. In order to resolve the details crucial for understanding the topical problems of condensed matter physics, three quantities need to be minimized: uncertainty* in photon energy, uncertainty in kinetic energy of photoelectrons and temperature of the sample. In our approach we combine three recent achievements in the field of synchrotron radiation, surface science and cryogenics. We use synchrotron radiation with tunable photon energy contributing an uncertainty of the order of 1 meV, an electron energy analyzer which detects the kinetic energies with a precision of the order of 1 meV and a He3 cryostat which allows us to keep the temperature of the sample below 1 K. We discuss the exemplary results obtained on single crystals of Sr2RuO4 and some other materials. The electronic structure of this material can be

  5. Angle-resolved photoemission spectroscopy at ultra-low temperatures.

    PubMed

    Borisenko, Sergey V; Zabolotnyy, Volodymyr B; Kordyuk, Alexander A; Evtushinsky, Danil V; Kim, Timur K; Carleschi, Emanuela; Doyle, Bryan P; Fittipaldi, Rosalba; Cuoco, Mario; Vecchione, Antonio; Berger, Helmut

    2012-01-01

    The physical properties of a material are defined by its electronic structure. Electrons in solids are characterized by energy (ω) and momentum (k) and the probability to find them in a particular state with given ω and k is described by the spectral function A(k, ω). This function can be directly measured in an experiment based on the well-known photoelectric effect, for the explanation of which Albert Einstein received the Nobel Prize back in 1921. In the photoelectric effect the light shone on a surface ejects electrons from the material. According to Einstein, energy conservation allows one to determine the energy of an electron inside the sample, provided the energy of the light photon and kinetic energy of the outgoing photoelectron are known. Momentum conservation makes it also possible to estimate k relating it to the momentum of the photoelectron by measuring the angle at which the photoelectron left the surface. The modern version of this technique is called Angle-Resolved Photoemission Spectroscopy (ARPES) and exploits both conservation laws in order to determine the electronic structure, i.e. energy and momentum of electrons inside the solid. In order to resolve the details crucial for understanding the topical problems of condensed matter physics, three quantities need to be minimized: uncertainty* in photon energy, uncertainty in kinetic energy of photoelectrons and temperature of the sample. In our approach we combine three recent achievements in the field of synchrotron radiation, surface science and cryogenics. We use synchrotron radiation with tunable photon energy contributing an uncertainty of the order of 1 meV, an electron energy analyzer which detects the kinetic energies with a precision of the order of 1 meV and a He(3) cryostat which allows us to keep the temperature of the sample below 1 K. We discuss the exemplary results obtained on single crystals of Sr2RuO4 and some other materials. The electronic structure of this material can be

  6. High-Resolution, Noninvasive, Two-Photon Fluorescence Measurement of Molecular Concentrations in Corneal Tissue

    PubMed Central

    Cui, Liping; Huxlin, Krystel R.; Xu, Lisen; MacRae, Scott

    2011-01-01

    Purpose. To perform high-resolution, noninvasive, calibrated measurements of the concentrations and diffusion profiles of fluorescent molecules in the live cornea after topical application to the ocular surface. Methods. An 800-nm femtosecond laser was used to perform two-photon fluorescence (TPF) axial scanning measurements. Calibration solutions consisting of sodium fluorescein (Na-Fl; concentration range, 0.01%–2.5%) and riboflavin (concentration range, 0.0125%–0.1%) were tested in well slides, and TPF signals were assessed. Excised feline eyeballs preserved in corneal storage medium and with either intact or removed corneal epithelia were then treated with Na-Fl, riboflavin, or fluorescein dextran (Fl-d) of different molecular weight (MW) for 30 minutes. Calibrated TPF was then used immediately to measure the concentration of these molecules across the central corneal depth. Results. The axial resolution of our TPF system was 6 μm, and a linear relationship was observed between TPF signal and low concentrations of most fluorophores. Intact corneas treated with Na-Fl or riboflavin exhibited a detectable penetration depth of only approximately 20 μm, compared with approximately 400 to 600 μm when the epithelium was removed before fluorophore application. Peak concentrations for intact corneas were half those attained with epithelial removal. Debrided corneas treated with 2,000,000 MW Fl-d showed a half-maximum penetration depth of 156.7 μm compared with 384 μm for the 3,000 MW dextran. The peak concentration of the high MW dextran was one quarter that of the lower MW dextran. Conclusions. TPF is an effective, high-resolution, noninvasive method of quantifying the diffusion and concentration of fluorescent molecules across the cornea. PMID:21228379

  7. Electronic Structure of the Topological Insulator Bi2Se3 Using Angle-Resolved Photoemission Spectroscopy: Evidence for a Nearly Full Surface Spin Polarization

    SciTech Connect

    Z Pan; E Vescovo; A Fedorov; D Gardner; Y Lee; S Chu; G Gu; T Valla

    2011-12-31

    We performed high-resolution spin- and angle-resolved photoemission spectroscopy studies of the electronic structure and the spin texture on the surface of Bi{sub 2}Se{sub 3}, a model TI. By tuning the photon energy, we found that the topological surface state is well separated from the bulk states in the vicinity of k{sub z} = Z plane of the bulk Brillouin zone. The spin-resolved measurements in that region indicate a very high degree of spin polarization of the surface state, {approx}0.75, much higher than previously reported. Our results demonstrate that the topological surface state on Bi{sub 2}Se{sub 3} is highly spin polarized and that the dominant factors limiting the polarization are mainly extrinsic.

  8. Electronic Structure of the Topological Insulator Bi2Se3 Using Angle-Resolved Photoemission Spectroscopy: Evidence for a Nearly Full Surface Spin Polarization

    SciTech Connect

    Pan, Z.H.; Vescovo, E.; Fedorov, A.V.; Gardner, D.; Lee, Y.S.; Chu, S.; Gu, G.D.; Valla, T.

    2011-06-22

    We performed high-resolution spin- and angle-resolved photoemission spectroscopy studies of the electronic structure and the spin texture on the surface of Bi{sub 2}Se{sub 3}, a model TI. By tuning the photon energy, we found that the topological surface state is well separated from the bulk states in the vicinity of k{sub z} = Z plane of the bulk Brillouin zone. The spin-resolved measurements in that region indicate a very high degree of spin polarization of the surface state, {approx}0.75, much higher than previously reported. Our results demonstrate that the topological surface state on Bi{sub 2}Se{sub 3} is highly spin polarized and that the dominant factors limiting the polarization are mainly extrinsic.

  9. High-Resolution Correlated Fission Product Measurements of 235U (nth , f) with SPIDER

    NASA Astrophysics Data System (ADS)

    Shields, Dan; Spider Team

    2015-10-01

    The SPIDER detector (SPectrometer for Ion DEtermination in fission Research) has obtained high-resolution, moderate-efficiency, correlated fission product data needed for many applications including the modeling of next generation nuclear reactors, stockpile stewardship, and the fundamental understanding of the fission process. SPIDER simultaneously measures velocity and energy of both fission products to calculate fission product yields (FPYs), neutron multiplicity (ν), and total kinetic energy (TKE). These data will be some of the first of their kind available to nuclear data evaluations. An overview of the SPIDER detector, analytical method, and preliminary results for 235U (nth , f) will be presented. LA-UR-15-20130 This work benefited from the use of the LANSCE accelerator facility and was performed under the auspices of the US Department of Energy by Los Alamos Security, LLC under Contract DE-AC52-06NA25396.

  10. Measurement of magnetic field aligned potential differences using high resolution conjugate photoelectron energy spectra

    NASA Technical Reports Server (NTRS)

    Peterson, W. K.; Doering, J. P.; Potemra, T. A.; Bostrom, C. O.; Brace, L. H.; Heelis, R. A.; Hanson, W. B.

    1977-01-01

    Simultaneous high-resolution observations of a distinctive feature in the energy spectrum of conjugate photoelectrons and spacecraft potential relative to the local ionosphere have allowed the net potential difference between magnetic conjugate points at latitudes below the region of low-energy (i.e., lower than 100 eV) auroral electron precipitation to be determined. Measurements made at 300 km from Atmosphere Explorer C show that there is normally no net potential difference between hemispheres in this region, which extended up to invariant latitudes as high as 74 deg. Two types of apparently related anomalous behavior were infrequently observed at high latitudes. During these periods the incident flux of conjugate photoelectrons was either decelerated by about 3 eV or was not detected.

  11. Proton-silicon interaction potential extracted from high-resolution measurements of crystal rainbows

    NASA Astrophysics Data System (ADS)

    Petrović, S.; Nešković, N.; Ćosić, M.; Motapothula, M.; Breese, M. B. H.

    2015-10-01

    This study provides a way to produce very accurate ion-atom interaction potentials. We present the high-resolution measurements of angular distributions of protons of energies between 2.0 and 0.7 MeV channeled in a 55 nm thick (0 0 1) silicon membrane. Analysis is performed using the theory of crystal rainbows in which the Molière's interaction potential is modified to make it accurate both close to the channel axis and close to the atomic strings defining the channel. This modification is based on adjusting the shapes of the rainbow lines appearing in the transmission angle plane, with the resulting theoretical angular distributions of transmitted protons being in excellent agreement with the corresponding experimental distributions.

  12. Potassium stable isotopic compositions measured by high-resolution MC-ICP-MS

    NASA Astrophysics Data System (ADS)

    Morgan, L. E.; Lloyd, N. S.; Ellam, R. M.; Simon, J. I.

    2012-12-01

    Potassium isotopic (41K/39K) compositions are notoriously difficult to measure. TIMS measurements are hindered by variable fractionation patterns throughout individual runs and too few isotopes to apply an internal spike method for instrumental mass fractionation corrections. Internal fractionation corrections via the 40K/39K ratio can provide precise values but assume identical 40K/39K ratios (e.g. 0.05‰ (1σ) in [1]); this is appropriate in some cases (e.g. identifying excess 41K) but not others (e.g., determining mass fractionation effects and metrologically traceable isotopic abundances). SIMS analyses have yielded measurements with 0.25‰ precisions (1σ) [2]. ICP-MS analyses are significantly affected by interferences from molecular species such as 38ArH+ and 40ArH+ and instrument mass bias. Single collector ICP-MS instruments in "cold plasma" mode have yielded uncertainties as low as 2‰ (1σ, e.g. [3]). Although these precisions may be acceptable for some concentration determinations, they do not resolve isotopic variation in terrestrial materials. Here we present data from a series of measurements made on the Thermo Scientific NEPTUNE Plus multi-collector ICP-MS that demonstrate the ability to make 41K/39K ratio measurements with 0.07‰ precisions (1σ). These data, collected on NIST K standards, indicate the potential for MC-ICP-MS measurements to look for K isotopic variations at the sub-permil level. The NEPTUNE Plus can sufficiently resolve 39K and 41K from the interfering 38ArH+ and 40ArH+ peaks in wet cold plasma and high-resolution mode. Measurements were made on small but flat, interference-free, plateaus (ca. 50 ppm by mass width for 41K). Although ICP-MS does not yield accurate 41K/39K values due to significant instrumental mass fractionation (ca. 6%), this bias can be sufficiently stable over the time required for several measurements so that relative 41K/39K values can be precisely determined via sample-standard bracketing. As cold plasma

  13. Potassium Stable Isotopic Compositions Measured by High-Resolution MC-ICP-MS

    NASA Technical Reports Server (NTRS)

    Morgan, Leah E.; Lloyd, Nicholas S.; Ellam, Robert M.; Simon, Justin I.

    2012-01-01

    Potassium isotopic (K-41/K-39) compositions are notoriously difficult to measure. TIMS measurements are hindered by variable fractionation patterns throughout individual runs and too few isotopes to apply an internal spike method for instrumental mass fractionation corrections. Internal fractionation corrections via the K-40/K-39 ratio can provide precise values but assume identical K-40/K-39 ratios (e.g. 0.05% (1sigma) in [1]); this is appropriate in some cases (e.g. identifying excess K-41) but not others (e.g., determining mass fractionation effects and metrologically traceable isotopic abundances). SIMS analyses have yielded measurements with 0.25% precisions (1sigma) [2]. ICP-MS analyses are significantly affected by interferences from molecular species such as Ar-38H(+) and Ar-40H(+) and instrument mass bias. Single collector ICP-MS instruments in "cold plasma" mode have yielded uncertainties as low as 2% (1sigma, e.g. [3]). Although these precisions may be acceptable for some concentration determinations, they do not resolve isotopic variation in terrestrial materials. Here we present data from a series of measurements made on the Thermo Scientific NEPTUNE Plus multi-collector ICP-MS that demonstrate the ability to make K-41/K-39 ratio measurements with 0.07% precisions (1sigma). These data, collected on NIST K standards, indicate the potential for MC-ICP-MS measurements to look for K isotopic variations at the sub-permil level. The NEPTUNE Plus can sufficiently resolve 39K and 41K from the interfering 38ArH+ and 40ArH+ peaks in wet cold plasma and high-resolution mode. Measurements were made on small but flat, interference-free, plateaus (ca. 50 ppm by mass width for K-41). Although ICP-MS does not yield accurate K-41/K-39 values due to significant instrumental mass fractionation (ca. 6%), this bias can be sufficiently stable over the time required for several measurements so that relative K-41/K-39 values can be precisely determined via sample

  14. High resolution optical surface metrology with the slope measuring portable optical test system

    NASA Astrophysics Data System (ADS)

    Maldonado, Alejandro V.

    New optical designs strive to achieve extreme performance, and continually increase the complexity of prescribed optical shapes, which often require wide dynamic range and high resolution. SCOTS, or the Software Configurable Optical Test System, can measure a wide range of optical surfaces with high sensitivity using surface slope. This dissertation introduces a high resolution version of SCOTS called SPOTS, or the Slope measuring Portable Optical Test System. SPOTS improves the metrology of surface features on the order of sub-millimeter to decimeter spatial scales and nanometer to micrometer level height scales. Currently there is no optical surface metrology instrument with the same utility. SCOTS uses a computer controlled display (such as an LCD monitor) and camera to measure surface slopes over the entire surface of a mirror. SPOTS differs in that an additional lens is placed near the surface under test. A small prototype system is discussed in general, providing the support for the design of future SPOTS devices. Then the SCOTS instrument transfer function is addressed, which defines the way the system filters surface heights. Lastly, the calibration and performance of larger SPOTS device is analyzed with example measurements of the 8.4-m diameter aspheric Large Synoptic Survey Telescope's (LSST) primary mirror. In general optical systems have a transfer function, which filters data. In the case of optical imaging systems the instrument transfer function (ITF) follows the modulation transfer function (MTF), which causes a reduction of contrast as a function of increasing spatial frequency due to diffraction. In SCOTS, ITF is shown to decrease the measured height of surface features as their spatial frequency increases, and thus the SCOTS and SPOTS ITF is proportional to their camera system's MTF. Theory and simulations are supported by a SCOTS measurement of a test piece with a set of lithographically written sinusoidal surface topographies. In addition, an

  15. Quantitative analysis of angle-resolved scattering properties of ovarian tissue using optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Yang, Yi; Wang, Tianheng; Brewer, Molly; Zhu, Quing

    2012-09-01

    Angle-resolved optical scattering properties of ovarian tissue, on different optical coherence tomography (OCT) imaging planes, were quantitatively measured by fitting the compounded OCT A-lines into a single scattering model. Higher cross correlation value of angle-resolved scattering coefficients between different OCT imaging planes was found in normal ovaries than was present in malignant ovaries. The mean cross correlation coefficient (MCC) was introduced in this pilot study to characterize and differentiate normal, n=6, and malignant, n=4, ovaries. A specificity of 100 percent and a sensitivity of 100 percent were achieved by setting MCC threshold at 0.6. Collagen properties, within the OCT imaging penetration depth, were also qualitatively studied in terms of their content, structure and directivity. The homogeneous three-dimensional collagen fiber network, observed in the normal ovary, effectively explains the stronger cross correlation of angle-resolved scattering properties on different imaging planes while the heterogeneity, observed in the malignant ovary, suggests a weaker correlation.

  16. Development of the Experimental System for Time- and Angle-resolved Photoemission Spectroscopy

    SciTech Connect

    Takahashi, Kazutoshi; Azuma, Junpei; Tokudomi, Shinji; Kamada, Masao

    2007-01-19

    Experimental system for the time- and angle-resolved photoemission spectroscopy have been constructed at BL13 in SAGA Light Source, in order to study the electronic non-equilibrium in the surface layer of laser-excited materials The experimental system is very useful for photoemission spectroscopy in the wide temporal and angular ranges. The time- and angle-resolved photoemission spectra can be obtained with using the gate electronics for the MCP detector of the photoemission spectrometer. The gated MCP detector is synchronized with the laser pulse from Ti:sapphire regenerative amplifier with the repetition frequency of 10 to 300 kHz. The time-window of the gated MCP detector can be changed between 10 nano- and 160 micro-second. The time-resolved measurement in pico-second region can be performed with using the pump-probe technique which uses fundamental, second and third harmonics from the Ti:sapphire laser as the excitation source. Using these systems, we can perform the time- and angle-resolved photoemission study for various photo-excited phenomena and surface dynamics.

  17. Concentration-Discharge Patterns Revealed from High Resolution Nitrate Measurements in Agricultural Landscapes

    NASA Astrophysics Data System (ADS)

    Boland, S. J.; Basu, N. B.

    2012-12-01

    Riverine export of nutrients is a major component of nutrient cycles, particularly with respect to nitrogen; ~ 25 percent of terrestrially applied nitrogen (N) is removed via riverine export. Understanding the patterns in N export during a storm event is critical for developing a conceptual model of the dominant processes and pathways of N transformation, and designing appropriate management strategies to mitigate N pollution in streams and receiving water bodies. Most studies however, are limited by the lack of high-resolution water quality data to elucidate these pathways and mechanisms. We explored concentration-discharge relationships using high-resolution (15 minute) discharge (Q) and nitrate concentration (C) data (measured using an in-situ Nitratax Sonde) at multiple nested scales (from 151.3 km2 to 8900 km2) in two watersheds in Iowa: Clear Creek Watershed and the Raccoon River watershed. Three distinct regimes of nitrate transport were revealed: (1) a linear regime in which C increases with increasing Q, (2) a saturation regime in which C remains constant against increasing Q, and (3) a dilution regime in which concentration decreases as Q increases. The tight clustering of the data along these patterns is indicative of emergent behavior in such human-dominated systems. All three regimes were apparent in the Raccoon River Watershed, while only the saturation and dilution regimes were apparent in the Clear Creek Watershed. We hypothesize that surface flow is dominant in the Clear Creek Watershed leading to a saturation/dilution regimes, while subsurface flow is dominant in the more heavily tile-drained Raccoon River Watershed, leading to the occurrence of all three regimes. A parsimonious model was developed to test the hypothesis and develop C-Q patterns as a function of the partitioning of flow through the different pathways.

  18. High-Resolution Neutron Total and Capture Cross-Section Measurements on 206Pb

    SciTech Connect

    Borella, A.; Brusegan, A.; Siegler, P.; Schillebeeckx, P.; Moxon, M.C.; Aerts, G.; Gunsing, F.

    2005-05-24

    High-resolution neutron total and capture cross-section measurements have been performed on a 99.82% enriched 206Pb metallic sample. The transmission and capture measurements were carried out at the 25- and 60-m stations, respectively, of the Time-Of-Flight facility GELINA of the IRMM in Geel (B). The small amount of material allowed us to detect 13 resonances below 80 keV in the transmission measurements and 70 were seen in the capture measurements below 150 keV. The resonance parameters for the resonances seen in transmission agree within the uncertainties of the parameters determined by Horen et al. at ORELA. The capture yield was measured up to 600 keV and the capture areas for resonances up to 150 keV were compared with published data. This comparison reveals systematic differences, which are due to the detection geometry, the different neutron sensitivity in the detection systems, the applied weighting function, and normalisation.

  19. Determination of band oscillator strengths of atmospheric molecules from high resolution vacuum ultraviolet cross section measurements

    NASA Technical Reports Server (NTRS)

    Parkinson, W. H.

    1986-01-01

    An account is given of progress in work on (1) the determination of band oscillator strengths of the Schumann-Runge absorption bands of (16)O2 and (18)O2 from cross section measurements conducted at 79 K; (2) the determination of the absolute absorption cross section of the Schumann-Runge bands of (16)O(18)O from optical depth measurements performed on mixtures of (16)O2, (18)O2 and (16)O(18)O at 79K; and (3) the influence of Schumann-Runge linewing contributions on the determination of the Herzberg continuum absorption cross section of (16)O2 in the wavelength region 194 to 204 nm. The experimental investigations are effected at high resolution with a 6.65 m scanning spectrometer which is, by virtue of its small instrumental width (EWHM = 0.0013 nm), uniquely suitable for cross section measurements of molecular bands with discrete rotational structure. Absolute cross sections, which are independent of the instrumental function and from which band oscillator strengths are directly determined, are measured for the absorption bands that are most predissociated. Such measurements are needed for (1) accurate calculations of the stratospheric production of atomic oxygen and heavy ozone formed following the photopredissociation of (18)O(16)O by solar radiation penetrating between the absorption lines of (16)O2; (2) elucidation of the mechanism of predissociation of the upper state of the Schumann-Runge bands; and (3) determination of the true shape of the Herzberg continuum cross section.

  20. On the measurement of frequency and of its sample variance with high-resolution counters

    SciTech Connect

    Rubiola, Enrico

    2005-05-15

    A frequency counter measures the input frequency {nu} averaged over a suitable time {tau}, versus the reference clock. High resolution is achieved by interpolating the clock signal. Further increased resolution is obtained by averaging multiple frequency measurements highly overlapped. In the presence of additive white noise or white phase noise, the square uncertainty improves from {sigma}{sub {nu}}{sup 2}{proportional_to}1/{tau}{sup 2} to {sigma}{sub {nu}}{sup 2}{proportional_to}1/{tau}{sup 3}. Surprisingly, when a file of contiguous data is fed into the formula of the two-sample (Allan) variance {sigma}{sub y}{sup 2}({tau})=E{l_brace}(1/2)(y{sub k+1}-y{sub k}){sup 2}{r_brace} of the fractional frequency fluctuation y, the result is the modified Allan variance mod {sigma}{sub y}{sup 2}({tau}). But if a sufficient number of contiguous measures are averaged in order to get a longer {tau} and the data are fed into the same formula, the results is the (nonmodified) Allan variance. Of course interpretation mistakes are around the corner if the counter internal process is not well understood. The typical domain of interest is the the short-term stability measurement of oscillators.

  1. A compact and miniaturized high resolution capacitance dilatometer for measuring thermal expansion and magnetostriction

    SciTech Connect

    Kuechler, R.; Bauer, T.; Brando, M.; Steglich, F.

    2012-09-15

    We describe the design, construction, calibration, and two different applications of a miniature capacitance dilatometer. The device is suitable for thermal expansion and magnetostriction measurements from 300 K down to about 25 mK, with a resolution of 0.02 A at low temperatures. The main body of the dilatometer is fabricated from a single block of a Be-Cu alloy by electrical discharge milling. This creates an extremely compact high-resolution measuring cell. We have successfully tested and operated dilatometers of this new type with the commonly used physical property measurement system by quantum design, as well as with several other cryogenic refrigeration systems down to 25 mK and in magnetic fields up to 20 T. Here, the capacitance is measured with a commercially available capacitance bridge. Using a piezoelectric rotator from Attocube Systems, the cell can be rotated at T= 25 mK inside of an inner vacuum chamber of 40 mm diameter. The miniaturized design for the one-axis rotation setup allows a rotation of 360 Degree-Sign .

  2. High-resolution atmospheric water vapor measurements with a scanning differential absorption lidar

    NASA Astrophysics Data System (ADS)

    Späth, F.; Behrendt, A.; Muppa, S. K.; Metzendorf, S.; Riede, A.; Wulfmeyer, V.

    2014-11-01

    The scanning differential absorption lidar (DIAL) of the University of Hohenheim (UHOH) is presented. The UHOH DIAL is equipped with an injection-seeded frequency-stabilized high-power Ti:sapphire laser operated at 818 nm with a repetition rate of 250 Hz. A scanning transceiver unit with a 80 cm primary mirror receives the atmospheric backscatter signals. The system is capable of water vapor measurements with temporal resolutions of a few seconds and a range resolution between 30 and 300 m at daytime. It allows to investigate surface-vegetation-atmosphere exchange processes with high resolution. In this paper, we present the design of the instrument and illustrate its performance with recent water vapor measurements taken in Stuttgart-Hohenheim and in the frame of the HD(CP)2 Observational Prototype Experiment (HOPE). HOPE was located near research center Jülich, in western Germany, in spring 2013 as part of the project "High Definition of Clouds and Precipitation for advancing Climate Prediction" (HD(CP)2). Scanning measurements reveal the 3-dimensional structures of the water vapor field. The influence of uncertainties within the calculation of the absorption cross-section at wavelengths around 818 nm for the WV retrieval is discussed. Radiosonde intercomparisons show a very small bias between the instruments of only (-0.04 ± 0.11) g m-3 or (-1.0 ± 2.3) % in the height range of 0.5 to 3 km.

  3. Multiple apolipoprotein kinetics measured in human HDL by high-resolution/accurate mass parallel reaction monitoring.

    PubMed

    Singh, Sasha A; Andraski, Allison B; Pieper, Brett; Goh, Wilson; Mendivil, Carlos O; Sacks, Frank M; Aikawa, Masanori

    2016-04-01

    Endogenous labeling with stable isotopes is used to study the metabolism of proteins in vivo. However, traditional detection methods such as GC/MS cannot measure tracer enrichment in multiple proteins simultaneously, and multiple reaction monitoring MS cannot measure precisely the low tracer enrichment in slowly turning-over proteins as in HDL. We exploited the versatility of the high-resolution/accurate mass (HR/AM) quadrupole Orbitrap for proteomic analysis of five HDL sizes. We identified 58 proteins in HDL that were shared among three humans and that were organized into five subproteomes according to HDL size. For seven of these proteins, apoA-I, apoA-II, apoA-IV, apoC-III, apoD, apoE, and apoM, we performed parallel reaction monitoring (PRM) to measure trideuterated leucine tracer enrichment between 0.03 to 1.0% in vivo, as required to study their metabolism. The results were suitable for multicompartmental modeling in all except apoD. These apolipoproteins in each HDL size mainly originated directly from the source compartment, presumably the liver and intestine. Flux of apolipoproteins from smaller to larger HDL or the reverse contributed only slightly to apolipoprotein metabolism. These novel findings on HDL apolipoprotein metabolism demonstrate the analytical breadth and scope of the HR/AM-PRM technology to perform metabolic research. PMID:26862155

  4. High resolution measurement of light in terrestrial ecosystems using photodegrading dyes.

    PubMed

    Roales, Javier; Durán, Jorge; Bechtold, Heather A; Groffman, Peter M; Rosi-Marshall, Emma J

    2013-01-01

    Incoming solar radiation is the main determinant of terrestrial ecosystem processes, such as primary production, litter decomposition, or soil mineralization rates. Light in terrestrial ecosystems is spatially and temporally heterogeneous due to the interaction among sunlight angle, cloud cover and tree-canopy structure. To integrate this variability and to know light distribution over time and space, a high number of measurements are needed, but tools to do this are usually expensive and limited. An easy-to-use and inexpensive method that can be used to measure light over time and space is needed. We used two photodegrading fluorescent organic dyes, rhodamine WT (RWT) and fluorescein, for the quantification of light. We measured dye photodegradation as the decrease in fluorescence across an irradiance gradient from full sunlight to deep shade. Then, we correlated it to accumulated light measured with PAR quantum sensors and obtained a model for this behavior. Rhodamine WT and fluorescein photodegradation followed an exponential decay curve with respect to accumulated light. Rhodamine WT degraded slower than fluorescein and remained unaltered after exposure to temperature changes. Under controlled conditions, fluorescence of both dyes decreased when temperatures increased, but returned to its initial values after cooling to the pre-heating temperature, indicating no degradation. RWT and fluorescein can be used to measure light under a varying range of light conditions in terrestrial ecosystems. This method is particularly useful to integrate solar radiation over time and to measure light simultaneously at different locations, and might be a better alternative to the expensive and time consuming traditional light measurement methods. The accuracy, low price and ease of this method make it a powerful tool for intensive sampling of large areas and for developing high resolution maps of light in an ecosystem. PMID:24069440

  5. A High Resolution Fourier-Transform Spectrometer for the Measurement of Atmospheric Column Abundances

    NASA Technical Reports Server (NTRS)

    Cageao, R.; Sander, S.; Blavier, J.; Jiang, Y.; Nemtchinov, V.

    2000-01-01

    A compact, high resolution Fourier-transform spectrometer for atmospheric near ultraviolet spectroscopy has been installed at the Jet Propulsion Laboratory's Table Mountain Facility (34.4N, 117.7 W, elevation 2290m).

  6. Angle-resolved effective potentials for disk-shaped molecules

    SciTech Connect

    Heinemann, Thomas Klapp, Sabine H. L.; Palczynski, Karol Dzubiella, Joachim

    2014-12-07

    We present an approach for calculating coarse-grained angle-resolved effective pair potentials for uniaxial molecules. For integrating out the intramolecular degrees of freedom we apply umbrella sampling and steered dynamics techniques in atomistically-resolved molecular dynamics (MD) computer simulations. Throughout this study we focus on disk-like molecules such as coronene. To develop the methods we focus on integrating out the van der Waals and intramolecular interactions, while electrostatic charge contributions are neglected. The resulting coarse-grained pair potential reveals a strong temperature and angle dependence. In the next step we fit the numerical data with various Gay-Berne-like potentials to be used in more efficient simulations on larger scales. The quality of the resulting coarse-grained results is evaluated by comparing their pair and many-body structure as well as some thermodynamic quantities self-consistently to the outcome of atomistic MD simulations of many-particle systems. We find that angle-resolved potentials are essential not only to accurately describe crystal structures but also for fluid systems where simple isotropic potentials start to fail already for low to moderate packing fractions. Further, in describing these states it is crucial to take into account the pronounced temperature dependence arising in selected pair configurations due to bending fluctuations.

  7. Angle-resolved effective potentials for disk-shaped molecules

    NASA Astrophysics Data System (ADS)

    Heinemann, Thomas; Palczynski, Karol; Dzubiella, Joachim; Klapp, Sabine H. L.

    2014-12-01

    We present an approach for calculating coarse-grained angle-resolved effective pair potentials for uniaxial molecules. For integrating out the intramolecular degrees of freedom we apply umbrella sampling and steered dynamics techniques in atomistically-resolved molecular dynamics (MD) computer simulations. Throughout this study we focus on disk-like molecules such as coronene. To develop the methods we focus on integrating out the van der Waals and intramolecular interactions, while electrostatic charge contributions are neglected. The resulting coarse-grained pair potential reveals a strong temperature and angle dependence. In the next step we fit the numerical data with various Gay-Berne-like potentials to be used in more efficient simulations on larger scales. The quality of the resulting coarse-grained results is evaluated by comparing their pair and many-body structure as well as some thermodynamic quantities self-consistently to the outcome of atomistic MD simulations of many-particle systems. We find that angle-resolved potentials are essential not only to accurately describe crystal structures but also for fluid systems where simple isotropic potentials start to fail already for low to moderate packing fractions. Further, in describing these states it is crucial to take into account the pronounced temperature dependence arising in selected pair configurations due to bending fluctuations.

  8. Angle-resolved effective potentials for disk-shaped molecules.

    PubMed

    Heinemann, Thomas; Palczynski, Karol; Dzubiella, Joachim; Klapp, Sabine H L

    2014-12-01

    We present an approach for calculating coarse-grained angle-resolved effective pair potentials for uniaxial molecules. For integrating out the intramolecular degrees of freedom we apply umbrella sampling and steered dynamics techniques in atomistically-resolved molecular dynamics (MD) computer simulations. Throughout this study we focus on disk-like molecules such as coronene. To develop the methods we focus on integrating out the van der Waals and intramolecular interactions, while electrostatic charge contributions are neglected. The resulting coarse-grained pair potential reveals a strong temperature and angle dependence. In the next step we fit the numerical data with various Gay-Berne-like potentials to be used in more efficient simulations on larger scales. The quality of the resulting coarse-grained results is evaluated by comparing their pair and many-body structure as well as some thermodynamic quantities self-consistently to the outcome of atomistic MD simulations of many-particle systems. We find that angle-resolved potentials are essential not only to accurately describe crystal structures but also for fluid systems where simple isotropic potentials start to fail already for low to moderate packing fractions. Further, in describing these states it is crucial to take into account the pronounced temperature dependence arising in selected pair configurations due to bending fluctuations. PMID:25481132

  9. High-Resolution Measurements of the K-Shell Spectral Lines of Hydrogenlike and Heliumlike Xenon

    SciTech Connect

    Windman, K.; Beiersdorfer, P.; Brown, G.V.; Crespo, J.R.; Osterheld, A.L.; Reed, K.J.; Scofield, J.H.; Utter, S.B.

    1999-09-13

    With the implementation of a transmission-type curved crystal spectrometer at the Livermore high-energy electron beam ion trap (SuperEBIT) the window on sub-eV level measurements of the ground-state quantum electrodynamics and the two-electron quantum electrodynamics of high-Z ions has been opened. High-resolution spectroscopic measurements of the K{alpha} spectra of hydrogenlike Xe{sup 53+} and heliumlike Xe{sup 52+} are presented. The electron-impact excitation cross sections have been determined relative to the radiative recombination cross sections. The electron-impact energy was 112 keV which is about 3.7 times the excitation threshold for the n = 2 {yields} 1 transitions. Although the relative uncertainties of the measured electron-impact excitation cross sections range from about 20% to 50%, significant disagreement between the measured and calculated cross section values has been found for one of the heliumlike xenon lines. Overall, the comparison between experiment and theory shows that already for xenon (Z=54) the Breit interaction plays a significant part in the collisional excitation process. The measured cross sections for the hydrogenlike transitions are in good agreement with theoretical predictions. Additionally, the Xe{sup 53+} Ly-{alpha}{sub 1} transition energy has been measured utilizing the K{alpha} emission of neutral cesium and barium for calibration. Surprisingly, the experimental result, (31279.2 {+-} 1.5) eV, disagrees with the widely accepted theoretically predicted value of (31283.77 {+-} 0.09) eV. However, this disagreement does not (yet) call for any correction in respect to the theoretical values for the transition energies of the hydrogenlike isoelectronic sequence. It rather emphasizes the need for a reevaluation of the commonly used x-ray wavelengths table for atomic inner-shell transitions, in particular, for the cesium K{alpha} lines.

  10. Simultaneous high-resolution measurement of mitochondrial respiration and hydrogen peroxide production.

    PubMed

    Krumschnabel, Gerhard; Fontana-Ayoub, Mona; Sumbalova, Zuzana; Heidler, Juliana; Gauper, Kathrin; Fasching, Mario; Gnaiger, Erich

    2015-01-01

    Mitochondrial respiration is associated with the formation of reactive oxygen species, primarily in the form of superoxide (O2 (•-)) and particularly hydrogen peroxide (H2O2). Since H2O2 plays important roles in physiology and pathology, measurement of hydrogen peroxide has received considerable attention over many years. Here we describe how the well-established Amplex Red assay can be used to detect H2O2 production in combination with the simultaneous assessment of mitochondrial bioenergetics by high-resolution respirometry. Fundamental instrumental and methodological parameters were optimized for analysis of the effects of various substrate, uncoupler, and inhibitor titrations (SUIT) on respiration versus H2O2 production. The sensitivity of the H2O2 assay was strongly influenced by compounds contained in different mitochondrial respiration media, which also exerted significant effects on chemical background fluorescence changes. Near linearity of the fluorescence signal was restricted to narrow ranges of accumulating resorufin concentrations independent of the nature of mitochondrial respiration media. Finally, we show an application example using isolated mouse brain mitochondria as an experimental model for the simultaneous measurement of mitochondrial respiration and H2O2 production in SUIT protocols. PMID:25631019

  11. Graphene Nanopore Support System for Simultaneous High-Resolution AFM Imaging and Conductance Measurements

    PubMed Central

    2015-01-01

    Accurately defining the nanoporous structure and sensing the ionic flow across nanoscale pores in thin films and membranes has a wide range of applications, including characterization of biological ion channels and receptors, DNA sequencing, molecule separation by nanoparticle films, sensing by block co-polymers films, and catalysis through metal–organic frameworks. Ionic conductance through nanopores is often regulated by their 3D structures, a relationship that can be accurately determined only by their simultaneous measurements. However, defining their structure–function relationships directly by any existing techniques is still not possible. Atomic force microscopy (AFM) can image the structures of these pores at high resolution in an aqueous environment, and electrophysiological techniques can measure ion flow through individual nanoscale pores. Combining these techniques is limited by the lack of nanoscale interfaces. We have designed a graphene-based single-nanopore support (∼5 nm thick with ∼20 nm pore diameter) and have integrated AFM imaging and ionic conductance recording using our newly designed double-chamber recording system to study an overlaid thin film. The functionality of this integrated system is demonstrated by electrical recording (<10 pS conductance) of suspended lipid bilayers spanning a nanopore and simultaneous AFM imaging of the bilayer. PMID:24581087

  12. Patterning pallet arrays for cell selection based on high-resolution measurements of fluorescent biosensors.

    PubMed

    Shadpour, Hamed; Zawistowski, Jon S; Herman, Annadele; Hahn, Klaus; Allbritton, Nancy L

    2011-06-24

    Pallet arrays enable cells to be separated while they remain adherent to a surface and provide a much greater range of cell selection criteria relative to that of current technologies. However there remains a need to further broaden cell selection criteria to include dynamic intracellular signaling events. To demonstrate the feasibility of measuring cellular protein behavior on the arrays using high resolution microscopy, the surfaces of individual pallets were modified to minimize the impact of scattered light at the pallet edges. The surfaces of the three-dimensional pallets on an array were patterned with a coating such as fibronectin using a customized stamping tool. Micropatterns of varying shape and size were printed in designated regions on the pallets in single or multiple steps to demonstrate the reliability and precision of patterning molecules on the pallet surface. Use of a fibronectin matrix stamped at the center of each pallet permitted the localization of H1299 and mouse embryonic fibroblast (MEF) cells to the pallet centers and away from the edges. Compared to pallet arrays with fibronectin coating the entire top surface, arrays with a central fibronectin pattern increased the percentage of cells localized to the pallet center by 3-4-fold. Localization of cells to the pallet center also enabled the physical separation of cells from optical artifacts created by the rough pallet side walls. To demonstrate the measurement of dynamic intracellular signaling on the arrays, fluorescence measurements of high spatial resolution were performed using a RhoA GTPase biosensor. This biosensor utilized fluorescence resonance energy transfer (FRET) between cyan fluorescent protein (CFP) and yellow fluorescent protein (YFP) to measure localized RhoA activity in cellular ruffles at the cell periphery. These results demonstrated the ability to perform spatially resolved measurements of fluorescence-based sensors on the pallet arrays. Thus, the patterned pallet arrays

  13. Inter-observer Variability in Esophageal Body Measurements with High Resolution Manometry among New Physician Users

    PubMed Central

    Singh, Erick; Rife, Christopher; Clayton, Steven; Naas, Peter; Nietert, Paul; Castell, Donald

    2012-01-01

    Goals To evaluate inter-observer variability among four new physician users on measures of esophageal body function. Background Esophageal high resolution manometry (HRM) allows observation of esophageal motility via pressure topography plots. Little is known about the inter-observer variability among physicians. Study Two resident and two fellow level physicians each interpreted 10 liquid swallows of 20 esophageal HRM studies (n=200 swallows) using the BioVIEW Analysis Suite (Sandhill Scientific, Inc.). Studies evaluated were from patients referred for evaluation of dysphagia but found to have normal esophageal manometry and complete liquid bolus transit. Physicians received an orientation session and reviewed recent literature. Each physician recorded contractile front velocity (CFV) and distal contractile integral (DCI) for each liquid swallow. STATISTICS: Inter-observer agreements for CFV and DCI were assessed by intraclass correlation (ICC) values. Linear correlations between measurements by two readers were assessed using linear regression modeling techniques. Results CFV and DCI values of up to 200 data points were analyzed. Four reader results for CFV and DCI showed strong agreement although stronger for DCI measures (ICC=0.94; 0.91 - 0.98) in comparison to CFV (ICC=0.79; 0.52 - 0.82). Further correlation was performed with two readers; readers 1 and 2 revealed excellent correlation for DCI (r=0.95, p<0.001) and good correlation for CFV (r=0.61, p<0.001). Conclusions With a thorough orientation session, good to excellent agreement for CFV and DCI measurements can be obtained from new physician users. CFV measures exhibit greater inter-observer variability possibly due to the artifact produced by intraesophageal pressurization. PMID:22647828

  14. High resolution as a key feature to perform accurate ELISPOT measurements using Zeiss KS ELISPOT readers.

    PubMed

    Malkusch, Wolf

    2005-01-01

    The enzyme-linked immunospot (ELISPOT) assay was originally developed for the detection of individual antibody secreting B-cells. Since then, the method has been improved, and ELISPOT is used for the determination of the production of tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, or various interleukins (IL)-4, IL-5. ELISPOT measurements are performed in 96-well plates with nitrocellulose membranes either visually or by means of image analysis. Image analysis offers various procedures to overcome variable background intensity problems and separate true from false spots. ELISPOT readers offer a complete solution for precise and automatic evaluation of ELISPOT assays. Number, size, and intensity of each single spot can be determined, printed, or saved for further statistical evaluation. Cytokine spots are always round, but because of floating edges with the background, they have a nonsmooth borderline. Resolution is a key feature for a precise detection of ELISPOT. In standard applications shape and edge steepness are essential parameters in addition to size and color for an accurate spot recognition. These parameters need a minimum spot diameter of 6 pixels. Collecting one single image per well with a standard color camera with 750 x 560 pixels will result in a resolution much too low to get all of the spots in a specimen. IFN-gamma spots may have only 25 microm diameters, and TNF-alpha spots just 15 microm. A 750 x 560 pixel image of a 6-mm well has a pixel size of 12 microm, resulting in only 1 or 2 pixel for a spot. Using a precise microscope optic in combination with a high resolution (1300 x 1030 pixel) integrating digital color camera, and at least 2 x 2 images per well will result in a pixel size of 2.5 microm and, as a minimum, 6 pixel diameter per spot. New approaches try to detect two cytokines per cell at the same time (i.e., IFN-gamma and IL-5). Standard staining procedures produce brownish spots (horseradish peroxidase) and blue spots

  15. Biaxial Mechanical Testing of Posterior Sclera using High-Resolution Ultrasound Speckle Tracking for Strain Measurements

    PubMed Central

    Cruz-Perez, Benjamin; Tang, Junhua; Morris, Hugh J.; Palko, Joel R.; Pan, Xueliang; Hart, Richard T.; Liu, Jun

    2014-01-01

    This study aimed to characterize the mechanical responses of the sclera, the white outer coat of the eye, under equal-biaxial loading with unrestricted shear. An ultrasound speckle tracking technique was used to measure tissue deformation through sample thickness, expanding the capabilities of surface strain techniques. Eight porcine scleral samples were tested within 72 hours postmortem. High resolution ultrasound scans of scleral cross-sections along the two loading axes were acquired at 25 consecutive biaxial load levels. An additional repeat of the biaxial loading cycle was performed to measure a third normal strain emulating a strain gauge rosette for calculating the in-plane shear. The repeatability of the strain measurements during identical biaxial ramps was evaluated. A correlation-based ultrasound speckle tracking algorithm was used to compute the displacement field and determine the distributive strains in the sample cross-sections. A Fung type constitutive model including a shear term was used to determine the material constants of each individual specimen by fitting the model parameters to the experimental stress-strain data. A non-linear stress-strain response was observed in all samples. The meridian direction had significantly larger strains than the circumferential direction during equal-biaxial loadings (P’s<0.05). The stiffness along the two directions were also significantly different (P=0.02) but highly correlated (R2=0.8). These results showed that the mechanical properties of the porcine sclera were nonlinear and anisotropic under biaxial loading. This work has also demonstrated the feasibility of using ultrasound speckle tracking for strain measurements during mechanical testing. PMID:24438767

  16. High resolution measurement of neutron inelastic scattering cross-sections for 23Na

    NASA Astrophysics Data System (ADS)

    Rouki, C.; Archier, P.; Borcea, C.; De Saint Jean, C.; Drohé, J. C.; Kopecky, S.; Moens, A.; Nankov, N.; Negret, A.; Noguère, G.; Plompen, A. J. M.; Stanoiu, M.

    2012-04-01

    The neutron inelastic scattering cross-section of 23Na has been measured in response to the relevant request of the OECD-NEA High Priority Request List, which requires a target uncertainty of 4% in the energy range up to 1.35 MeV for the development of sodium-cooled fast reactors. The measurement was performed at the GELINA facility with the Gamma Array for Inelastic Neutron Scattering (GAINS), featuring eight high purity germanium detectors. The setup is installed at a 200 m flight path from the neutron source and provides high resolution measurements using the (n,n'γ)-technique. The sample was an 80 mm diameter metallic sodium disk prepared at IRMM. Transitions up to the seventh excited state were observed and the differential gamma cross-sections at 110° and 150° were measured, showing mostly isotropic gamma emission. From these the gamma production, level and inelastic cross-sections were determined for neutron energies up to 3838.9 keV. The results agree well with the existing data and the evaluated nuclear data libraries in the low energies, and provide new experimental points in the little studied region above 2 MeV. Following a detailed review of the methodology used for the gamma efficiency calibrations and flux normalization of GAINS data, an estimated total uncertainty of 2.2% was achieved for the inelastic cross-section integrals over the energy ranges 0.498-1.35 MeV and 1.35-2.23 MeV, meeting the required targets.

  17. High-resolution surface connectivity measurements and runoff dynamics in five urban watersheds in Knoxville, TN

    NASA Astrophysics Data System (ADS)

    Epps, T.

    2015-12-01

    Impervious surfaces and stormwater drainage networks transmit rainfall quickly to urban stream systems with greater frequency, volume, energy, and pollutant loadings than in predevelopment conditions. This has a well-established negative impact on stream ecology, channel morphology, and water quality. Green infrastructure retrofits for urban drainage systems promote more natural hydrologic pathways by disconnecting concentrated flows. However, they are expensive due to high land costs and physical constraints. If a systematic strategy for siting green infrastructure is sought to restore natural flows throughout an urban catchment, greater knowledge of the drainage patterns and areas contributing frequent surface runoff is necessary. Five diverse urban watersheds in Knoxville, TN, were assessed using high-resolution topography, land cover, and artificial drainage network data to identify how surface connectivity differs among watersheds and contributes to altered flow regimes. Rainfall-runoff patterns were determined from continuous rainfall and streamflow monitoring over the previous ten years. Fine-scale flowpath connectivity of impervious surfaces was measured by both a binary approach and by a method incorporating runoff potential by saturation excess. The effect of the spatial distribution of connected surfaces was investigated by incorporating several distance-weighting schema along established urban drainage flowpaths. Statistical relationships between runoff generation and connectivity were measured to determine the ability of these different measures of connectivity to predict runoff thresholds, frequency, volumes, and peak flows. Initial results suggest that rapid assessment of connected surficial flowpaths can be used to identify known green infrastructure assets and highly connected impervious areas and that the differences in connectivity measured between watersheds reflects differing runoff patterns observed in monitored data.

  18. Hydrographical long term measurements and high resolution transects in tidal estuaries of the Southern North Sea

    NASA Astrophysics Data System (ADS)

    Badewien, Thomas H.; Schulz, Anne-Christin; Holinde, Lars; Zielinski, Oliver

    2013-04-01

    The tidal flats of the Wadden Sea and connected estuaries such as the Ems-Dollart are highly dynamic and diverse ecosystems and are of high economic value to the neighbouring regions. The Institute for Chemistry and Biology of the Marine Environment (ICBM) at the University of Oldenburg has expertise in observing and analysing environmental data from such complex systems. A research platform located at a tidal inlet between the East Frisian Islands Spiekeroog and Langeoog has collected hydrographical, meteorological and biogeochemical time series data for more than ten years. Currently, the bilateral Dutch-German research project "Future-Ems" deals with the highly dynamic exchange processes of the river Ems and its estuary (Dollart). Here, we present hydrographical long-term data sets obtained from the research platform as well as short-term high-resolution measurements from the same location and the river Ems. We focus on exchange and mixing processes as well as water mass transport through the respective tidal channels.

  19. Spatial variability of the Black Sea surface temperature from high resolution modeling and satellite measurements

    NASA Astrophysics Data System (ADS)

    Mizyuk, Artem; Senderov, Maxim; Korotaev, Gennady

    2016-04-01

    Large number of numerical ocean models were implemented for the Black Sea basin during last two decades. They reproduce rather similar structure of synoptical variability of the circulation. Since 00-s numerical studies of the mesoscale structure are carried out using high performance computing (HPC). With the growing capacity of computing resources it is now possible to reconstruct the Black Sea currents with spatial resolution of several hundreds meters. However, how realistic these results can be? In the proposed study an attempt is made to understand which spatial scales are reproduced by ocean model in the Black Sea. Simulations are made using parallel version of NEMO (Nucleus for European Modelling of the Ocean). A two regional configurations with spatial resolutions 5 km and 2.5 km are described. Comparison of the SST from simulations with two spatial resolutions shows rather qualitative difference of the spatial structures. Results of high resolution simulation are compared also with satellite observations and observation-based products from Copernicus using spatial correlation and spectral analysis. Spatial scales of correlations functions for simulated and observed SST are rather close and differs much from satellite SST reanalysis. Evolution of spectral density for modelled SST and reanalysis showed agreed time periods of small scales intensification. Using of the spectral analysis for satellite measurements is complicated due to gaps. The research leading to this results has received funding from Russian Science Foundation (project № 15-17-20020)

  20. Measurement of ciliary beat frequency using ultra-high resolution optical coherence tomography

    NASA Astrophysics Data System (ADS)

    Chen, Jason J.; Jing, Joseph C.; Su, Erica; Badger, Christopher; Coughlan, Carolyn A.; Chen, Zhongping; Wong, Brian J. F.

    2016-02-01

    Ciliated epithelial cells populate up to 80% of the surface area of the human airway and are responsible for mucociliary transport, which is the key protective mechanism that provides the first line of defense in the respiratory tract. Cilia beat in a rhythmic pattern and may be easily affected by allergens, pollutants, and pathogens, altering ciliary beat frequency (CBF) subsequently. Diseases including cystic fibrosis, chronic obstructive pulmonary disease, and primary ciliary dyskinesia may also decrease CBF. CBF is therefore a critical component of respiratory health. The current clinical method of measuring CBF is phase-contrast microscopy, which involves a tissue biopsy obtained via brushing of the nasal cavity. While this method is minimally invasive, the tissue sample must be oriented to display its profile view, making the visualization of a single layer of cilia challenging. In addition, the conventional method requires subjective analysis of CBF, e.g., manually counting by visual inspection. On the contrary, optical coherence tomography (OCT) has been used to study the retina in ophthalmology as well as vasculature in cardiology, and offers higher resolution than conventional computed tomography and magnetic resonance imaging. Based on this technology, our lab specifically developed an ultra-high resolution OCT system to image the microstructure of the ciliated epithelial cells. Doppler analysis was also performed to determine CBF. Lastly, we also developed a program that utilizes fast Fourier transform to determine CBF under phase-contrast microscopy, providing a more objective method compared to the current method.

  1. A modularized infrared light matrix system with high resolution for measuring animal behaviors.

    PubMed

    Young, M S; Li, Y C; Lin, M T

    1993-03-01

    The current study provides a new modularized infrared light matrix system (about $200 cost) which is designed to measure the horizontal gross or fine movements, vertical motion, clockwise or anticlockwise turnings, freezing time, and total distance traveled in rats. The system records the sequences of animal's activity in a computer-aided system with a resolution of 0.2 s in time or 1.6 cm in space, and permanently stores all the resulting data in file. The behavioral apparatus was tested for its sensitivity and usability by amphetamine-injected rats. It was found that intraperitoneal administration of amphetamine (1.25-2.50 mg/kg), but not normal saline, produced a dose-related increase in either the horizontal gross or fine movements, vertical motion, clockwise or anticlockwise turnings, or total distance traveled. However, amphetamine injections produced a dose-related decrease in freezing time. Apparently, most of the amphetamine-induced responses obtained by other detecting apparatus can be reproduced easily by the present apparatus. The current detection system possesses the following advantages: a) high resolution, b) high expansion potential, and c) precise and simplified algorithms for behavioral parameter analysis. PMID:8451322

  2. High-Resolution X-Ray and Light Beam Induced Current (LBIC) Measurements of Multcrystalline Silicon Solar Cells

    SciTech Connect

    Jellison Jr, Gerald Earle; Budai, John D; Bennett, Charlee J C; Tischler, Jonathan Zachary; Duty, Chad E; Yelundur, V.; Rohatgi, A.

    2010-01-01

    High-resolution, spatially-resolved x-ray Laue patterns and high-resolution light beam induced current (LBIC) measurements are combined to study two multicrystalline solar cells made from the Heat Exchanger Method (HEM) and the Sting Ribbon Growth technique. The LBIC measurements were made at 4 different wavelengths (488, 633, 780, and 980 nm), resulting in penetration depths ranging from <1 {mu}m to >100 {mu}m. There is a strong correlation between the x-ray and LBIC measurements, showing that some twins and grain boundaries are effective in the reduction of local quantum efficiency, while others are benign.

  3. High-resolution Measurement Of Magnetic Anomalies With An Unmanned Airship

    NASA Astrophysics Data System (ADS)

    Petzke, M.; Hofmeister, P.; Auster, H.; Hoerdt, A.; Glassmeier, K.

    2011-12-01

    High-resolution magnetic mapping of areas is a suitable way to determine location, geometry and physical parameters of disturbing objects that cause magnetic anomalies. Areas are often difficult to walk and handheld measurements can become costly. It can also be dangerous to enter areas where ordnance is suspected. In these cases it may be advantageous to use an aircraft to perform the measurement. We use a 6.5 m long unmanned airship. Compared to helicopters or gyrocopters, an advantage is that the damage in case of hazards is almost negligible. We made considerable efforts to construct a system that is easy to control without intense training under moderate wind conditions (up to 2 m/s wind speed). The airship has a mass of 10 kg and is powered by four electric motors with a maximum total power of 4.8 kW. Two of the rotors are used to control the altitude of the ship; the other two can be used to control direction and speed. The required energy is provided by four 4S1P Lithium-Polymer battery packs. Batteries are designed to provide a maximum of 125 A at 14.8 V. They have a capacity of 0.3 kWh and can be recharged in 20 minutes. The airship carries a differential GPS receiver that measures the position of the airship at 100 Hz with a precision of 10 cm. The distance to the ground is measured with ultrasonic sensors. A fluxgate magnetometer measures the magnetic field with an accuracy of 1 nT, also at 100 Hz. The flight path does not follow a rigid measuring grid but is a random walk, with roughly constant altitude to achieve a mean sensor position of 2 m above the ground. Thus, near-surface disturbing bodies are well resolved if their distance from each other is greater than 4 m. First measurements demonstrate the feasibility of the system. Future applications will be mid-scale measurements which are too large or too cumbersome for handheld measurements, and too small to justify the use of a manned helicopter.

  4. A high-resolution spectropolarimetric survey of Herbig Ae/Be stars - I. Observations and measurements

    NASA Astrophysics Data System (ADS)

    Alecian, E.; Wade, G. A.; Catala, C.; Grunhut, J. H.; Landstreet, J. D.; Bagnulo, S.; Böhm, T.; Folsom, C. P.; Marsden, S.; Waite, I.

    2013-02-01

    This is the first in a series of papers in which we describe and report the analysis of a large survey of Herbig Ae/Be stars in circular spectropolarimetry. Using the ESPaDOnS and Narval high-resolution spectropolarimeters at the Canada-France-Hawaii and Bernard Lyot Telescopes, respectively, we have acquired 132 circularly polarized spectra of 70 Herbig Ae/Be stars and Herbig candidates. The large majority of these spectra are characterized by a resolving power of about 65 000, and a spectral coverage from about 3700 Å to 1 μm. The peak signal-to-noise ratio per CCD pixel ranges from below 100 (for the faintest targets) to over 1000 (for the brightest). The observations were acquired with the primary aim of searching for magnetic fields in these objects. However, our spectra are suitable for a variety of other important measurements, including rotational properties, variability, binarity, chemical abundances, circumstellar environment conditions and structure, etc. In this paper, we describe the sample selection, the observations and their reduction, and the measurements that will comprise the basis of much of our following analysis. We describe the determination of fundamental parameters for each target. We detail the least-squares deconvolution (LSD) that we have applied to each of our spectra, including the selection, editing and tuning of the LSD line masks. We describe the fitting of the LSD Stokes I profiles using a multicomponent model that yields the rotationally broadened photospheric profile (providing the projected rotational velocity and radial velocity for each observation) as well as circumstellar emission and absorption components. Finally, we diagnose the longitudinal Zeeman effect via the measured circular polarization, and report the longitudinal magnetic field and Stokes V Zeeman signature detection probability. As an appendix, we provide a detailed review of each star observed.

  5. Differential membrane-based nanocalorimeter for high-resolution measurements of low-temperature specific heat.

    PubMed

    Tagliati, S; Krasnov, V M; Rydh, A

    2012-05-01

    A differential, membrane-based nanocalorimeter for general specific heat studies of very small samples, ranging from 0.5 mg to sub-μg in mass, is described. The calorimeter operates over the temperature range from above room temperature down to 0.5 K. It consists of a pair of cells, each of which is a stack of heaters and thermometer in the center of a silicon nitride membrane, in total giving a background heat capacity less than 100 nJ/K at 300 K, decreasing to 10 pJ/K at 1 K. The device has several distinctive features: (i) The resistive thermometer, made of a Ge(1 - x)Au(x) alloy, displays a high dimensionless sensitivity ∣dlnR∕dlnT∣ ≳ 1 over the entire temperature range. (ii) The sample is placed in direct contact with the thermometer, which is allowed to self-heat. The thermometer can thus be operated at high dc current to increase the resolution. (iii) Data are acquired with a set of eight synchronized lock-in amplifiers measuring dc, 1st and 2nd harmonic signals of heaters and thermometer. This gives high resolution and allows continuous output adjustments without additional noise. (iv) Absolute accuracy is achieved via a variable-frequency-fixed-phase technique in which the measurement frequency is automatically adjusted during the measurements to account for the temperature variation of the sample heat capacity and the device thermal conductance. The performance of the calorimeter is illustrated by studying the heat capacity of a small Au sample and the specific heat of a 2.6 μg piece of superconducting Pb in various magnetic fields. PMID:22667657

  6. An high resolution FDIRC for the measurement of cosmic-ray isotopic abundances

    NASA Astrophysics Data System (ADS)

    Marrocchesi, P. S.; Bagliesi, M. G.; Batkov, K.; Bigongiari, G.; Kim, M. Y.; Maestro, P.

    2011-08-01

    Measurements of the relative abundance of cosmic isotopes and of the energy dependence of their fluxes may clarify our present understanding on the confinement time of charged cosmic rays in the Galaxy. Experimental studies of these propagation clocks have been carried out by balloon and space missions at energies of a few 100 MeV/amu by means of detection techniques based on multiple d E/d x sampling, coupled with a measurement of the energy released in a thick absorber. At larger energies, the isotopic separation of light nuclei (as, for instance, 9Be/ 10Be) can be achieved by combining a precise measurement of the particle's rigidity with an high resolution determination of its velocity, via the observation of the Cherenkov effect in a radiator. In this paper, we propose the introduction - for the first time in a space experiment - of the DIRC technique (Detection of Internal Reflected Cherenkov light) for the identification of cosmic-ray isotopes. This type of detector has been successfully used in electron-positron colliders for particle identification and in particular for π-K separation. While for particles with unit charge the light yield is a limiting factor, in the case of a nucleus of charge Z the larger photostatistics (due to the Z2 dependence of Cherenkov light emission) is the key to reach an adequate angular resolution to provide a mass discrimination for isotopes of astrophysical interest. We report on the early development phase of a DIRC prototype with a focussing scheme (FDIRC) to collect the Cherenkov light onto a detector plane instrumented with a Silicon PhotoMultiplier (SiPM) array.

  7. Angle-resolved photoemission spectroscopy of the insulating NaxWO3: Anderson localization, polaron formation, and remnant Fermi surface.

    PubMed

    Raj, S; Hashimoto, D; Matsui, H; Souma, S; Sato, T; Takahashi, T; Sarma, D D; Mahadevan, Priya; Oishi, S

    2006-04-14

    The electronic structure of the insulating sodium tungsten bronze, Na(0.025)WO(3), is investigated by high-resolution angle-resolved photoemission spectroscopy. We find that near-E(F) states are localized due to the strong disorder arising from random distribution of Na+ ions in the WO(3) lattice, which makes the system insulating. The temperature dependence of photoemission spectra provides direct evidence for polaron formation. The remnant Fermi surface of the insulator is found to be the replica of the real Fermi surface in the metallic system. PMID:16712121

  8. High-resolution Sonographic Measurements of Lower Extremity Bursae in Chinese Healthy Young Men

    PubMed Central

    Gao, Yong-Yan; Wu, Chi-Qiu; Liu, Wei-Xing; Zhang, Lei; Li, Chun-Ling

    2016-01-01

    Background: Lower extremity bursae are very vulnerable to injury during strenuous physical exercises. Understanding the imaging characteristics of normal bursae is essential for early diagnosis of morphological abnormalities. Therefore, we evaluated the normal range of lower extremity bursae in healthy young men using high-resolution ultrasound (HR-US) imaging. Methods: Bursae in the lower extremities were examined by HR-US in 290 Chinese healthy young men with a median age of 18 years (range, 18–23 years). The bilateral suprapatellar bursa (SPB), deep infrapatellar bursa (DIPB), popliteal bursa (PB), and retrocalcaneal bursa (RCB) were imaged and measured for analysis. Results: The HR-US identification rates of the SPB, DIPB, PB, and RCB were 89.0% (517/580), 55.0% (319/580), 29.4% (171/580), and 49.5% (287/580), respectively. With the assumption that the bursae were normal in 95% of the study participants, the length and width values at the maximal cross-section of the SPB, DIPB, PB, and RCB were ≤18.00 and 6.09 mm, 8.10 and 2.11 mm, 7.67 and 3.93 mm, and 7.82 and 2.04 mm, respectively. Conclusions: Using HR-US imaging, we were able to analyze lower extremity bursae with high detection rates in healthy young men. The normal ranges of lower extremity bursa dimensions in healthy young men measured by HR-US in this study could be used as reference values for evaluation of bursa abnormalities in the lower extremity. PMID:26831233

  9. Angle-Resolved Second-Harmonic Light Scattering from Colloidal Particles

    SciTech Connect

    Yang, N.; Angerer, W. E.; Yodh, A. G.

    2001-09-03

    We report angle-resolved second-harmonic generation (SHG) measurements from suspensions of centrosymmetric micron-size polystyrene spheres with surface-adsorbed dye (malachite green). The second-harmonic scattering profiles differ qualitatively from linear light scattering profiles of the same particles. We investigated these radiation patterns using several polarization configurations and particle diameters. We introduce a simple Rayleigh-Gans-Debye model to account for the SHG scattering anisotropy. The model compares favorably with our experimental data. Our measurements suggest scattering anisotropy may be used to isolate particle nonlinear optics from other bulk nonlinear optical effects in suspension.

  10. Graphene on Ir(111) characterized by angle-resolved photoemission

    NASA Astrophysics Data System (ADS)

    Kralj, Marko; Pletikosić, Ivo; Petrović, Marin; Pervan, Petar; Milun, Milorad; N'Diaye, Alpha T.; Busse, Carsten; Michely, Thomas; Fujii, Jun; Vobornik, Ivana

    2011-08-01

    Angle-resolved photoelectron spectroscopy (ARPES) is extensively used to characterize the dependence of the electronic structure of graphene on Ir(111) on the preparation process. ARPES findings reveal that temperature-programmed growth alone or in combination with chemical vapor deposition leads to graphene displaying sharp electronic bands. The photoemission intensity of the Dirac cone is monitored as a function of the increasing graphene area. Electronic features of the moiré superstructure present in the system, namely, minigaps and replica bands are examined and used as robust features to evaluate graphene uniformity. The overall dispersion of the π band is analyzed. Finally, by the variation of photon energy, relative changes of the π and σ band intensities are demonstrated.

  11. Ambient Aerosol in Southeast Asia: High Resolution Aerosol Mass Spectrometer Measurements Over Oil Palm (Elaeis guineensis)

    NASA Astrophysics Data System (ADS)

    Phillips, G.; Dimarco, C.; Misztal, P.; Nemitz, E.; Farmer, D.; Kimmel, J.; Jimenez, J.

    2008-12-01

    The emission of organic compounds in the troposphere is important factor in the formation of secondary organic aerosol (SOA). A very large proportion of organic material emitted globally is estimated to arise from biogenic sources, with almost half coming from tropical and sub-tropical forests. Preliminary analyses of leave cuvette emission studies suggest that oil palm (Elaeis guineensis) is a significantly larger source of isoprene than tropical forest. Much larger sources of isoprene over oil palm allied with a larger anthropogenic component of local emissions contrast greatly with the remote tropical forest environment and therefore the character of SOA formed may differ significantly. These issues, allied with the high price of palm oil on international markets leading to increased use of land for oil palm production, could give rise to rapidly changing chemical and aerosol regimes in the tropics. It is therefore important to understand the current emissions and composition of organic aerosol over all important land-uses in the tropical environment. This in turn will lead to a greater understanding of the present, and to an improvement in predictive capacity for the future system. To help address these issues, a high resolution time of flight aerosol mass spectrometer (HR-ToF-AMS) was deployed in the Sabahmas (PPB OIL) oil palm plantation near Lahad Datu, in Eastern Sabah, as part of the field component of the Aerosol Coupling in the Earth System (ACES) project, part of the UK NERC APPRAISE program. This project was allied closely with measurements made of similar chemical species and aerosol components at a forest site in the Danum Valley as part of the UK Oxidant and Particle Photochemical Processes above a Southeast Asian tropical rainforest (OP3) project. Measurements of submicron non- refractory aerosol composition are presented along with some preliminary analysis of chemically resolved aerosol fluxes made with a new eddy covariance system, based on the

  12. Mid-latitude cirrus investigations at high-resolution through ground-based lidar measurements

    NASA Astrophysics Data System (ADS)

    Dionisi, Davide; Keckhut, Philippe; Hauchecorne, Alain; Gaudo, Thierry; Courcoux, Yann; Porteneuve, Jacques; Hoareau, Christophe; Congeduti, Fernando; Liberti, Gianluigi

    2013-04-01

    Although cirrus vertical distributions determine their local cooling or warming effects, one of the main missing information in Global Climate Models (GCMs) is the characterization of their vertical location and stratification. Lidar technique, in contrast, can detect cirrus with high spatial and temporal resolution, providing accurate information on their vertical distribution. In this work, the recent and on going studies about the the characterization of mid-latitude cirrus through lidar systems located at the Observatory of Haute Provence (OHP, 43.9 ° N, 5.7 ° E) in France and at Rome Tor Vergata (RTV, 41.8 ° N, 12.6 ° E) in Italy are presented. Cirrus have been firstly studied in terms of quasi-stationary periods regarding statistical variability. A clustering approach has been then adopted to derive cirrus classification (and climatology) over the period 1996-2007 for OHP lidar measurements and over 2007-2010 for RTV dataset. Three independent cirrus classes have been identified: I thin middle tropospheric cirrus, II thick upper tropospheric cirrus, III thin tropopause cirrus. The temporal variability of the optical properties of these classes has been then analyzed at lidar raw temporal sampling (180 sec). While advection dominates, at the first order, variability on timescale of minutes can be related to space fluctuations of cloud properties on typical scale of few kilometers. Lognormal distributions of the optical depth have been used to model variability of the cirrus optical depth as observed by lidars. Finally, the implementation of the OHP lidar system in terms of two analogic channels that collect the Rayleigh-Mie orthogonal and parallel component signals through an high-resolution acquisition chain (vertical and temporal sampling of 37.5 m and 1 sec, respectively) has been employed to investigate the high frequency cirrus variability in a recent campaign held at the OHP. The preliminary results of this campaign are also showed

  13. Work-function measurement by high-resolution scanning Kelvin nanoprobe

    NASA Astrophysics Data System (ADS)

    Cheran, Larisa-Emilia; Johnstone, Sherri; Sadeghi, Saman; Thompson, Michael

    2007-03-01

    Nanoscience promises to transform today's world in the same way that integrated semiconductor devices transformed the world of electronics and computation. In the post-genomic era, the greatest challenge is to make connections between the structures and functions of biomolecules at the nanometre-scale level in order to underpin the understanding of larger scale systems in the fields of human biology and physiology. To achieve this, instruments with new capabilities need to be researched and developed, with particular emphasis on new levels of sensitivity, precision and resolution for biomolecular analysis. This paper describes an instrument able to analyse structures that range from tenths of a nanometre (proteins, DNA) to micron-scale structures (living cells), which can be investigated non-destructively in their normal state and subsequently in chemical- or biochemical-modified conditions. The high-resolution scanning Kelvin nanoprobe (SKN) measures the work-function changes at molecular level, instigated by local charge reconfiguration due to translational motion of mobile charges, dipolar relaxation of bound charges, interfacial polarization and structural and conformational modifications. In addition to detecting surface electrical properties, the instrument offers, in parallel, the surface topographic image, with nanometre resolution. The instrument can also be used to investigate subtle work function/topography variations which occur in, for example, corrosion, contamination, adsorption and desorption of molecules, crystallographic studies, mechanical stress studies, surface photovoltaic studies, material science, biocompatibility studies, microelectronic characterization in semiconductor technology, oxide and thin films, surface processing and treatments, surfaces and interfaces characterization. This paper presents the design and development of the instrument, the basic principles of the method and the challenges involved to achieve nanometric resolution

  14. Size Effects in Angle-Resolved Photoelectron Spectroscopy of Free Rare-Gas Clusters

    SciTech Connect

    Rolles, D.; Zhang, H.; Pesic, Z.D.; Bilodeau, R.C.; Wills, A.; Kukk, E.; Rude, B.S.; Ackerman, G.D.; Bozek, J.D.; Muino, R.D.; de Abajo, F.J.G.; Berrah, N.; /Western Michigan U. /LBNL, ALS /Turku U. /SLAC /Basque U., San Sebastian /Madrid, Inst. Optica

    2007-05-23

    The photoionization of free Xe clusters is investigated by angle-resolved time-of-flight photoelectron spectroscopy. The measurements probe the evolution of the photoelectron angular distribution parameter as a function of photon energy and cluster size. While the overall photon-energy-dependent behavior of the photoelectrons from the clusters is very similar to that of the free atoms, distinct differences in the angular distribution point at cluster-size-dependent effects. Multiple scattering calculations trace their origin to elastic photoelectron scattering.

  15. MODTRAN3: An update and recent validations against airborne high resolution interferometer measurements

    NASA Technical Reports Server (NTRS)

    Anderson, Gail P.; Wang, Jinxue; Chetwynd, James H.

    1995-01-01

    accuracy of the code is very important because any errors in the radiative transfer calculation will directly translate into errors in the derived surface reflectance. In this paper, the new solar irradiance calculated by Kurucz, which is adopted in MODTRAN3, will be presented. Recent validations of MODTRAN3 with airborne high resolution interferometer measurements over ocean will be discussed. Good agreeement between model calculations and measurements was achieved.

  16. High-Resolution Fourier-Transform Ultraviolet-Visible Spectrometer for the Measurement of Atmospheric Trace Species: Application to OH.

    PubMed

    Cageao, R P; Blavier, J F; McGuire, J P; Jiang, Y; Nemtchinov, V; Mills, F P; Sander, S P

    2001-04-20

    A compact, high-resolution Fourier-transform spectrometer for atmospheric near-ultraviolet spectroscopy has been installed at the Jet Propulsion Laboratory's Table Mountain Facility (34.4 degrees N, 117.7 degrees W, elevation 2290 m). This instrument is designed with an unapodized resolving power near 500,000 at 300 nm to provide high-resolution spectra from 290 to 675 nm for the quantification of column abundances of trace atmospheric species. The measurement technique used is spectral analysis of molecular absorptions of solar radiation. The instrument, accompanying systems designs, and results of the atmospheric hydroxyl column observations are described. PMID:18357206

  17. Collision cross section measurements for biomolecules within a high-resolution FT-ICR cell: theory.

    PubMed

    Guo, Dan; Xin, Yi; Li, Dayu; Xu, Wei

    2015-04-14

    In this study, an energetic hard-sphere ion-neutral collision model was proposed to bridge-link ion collision cross section (CCS) with the image current collected from a high-resolution Fourier transform ion cyclotron resonance (FT-ICR) cell. By investigating the nonlinear effects induced by high-order electric fields and image charge forces, the energetic hard-sphere collision model was validated through experiments. Suitable application regions for the energetic hard-sphere collision model, as well as for the conventional Langevin and hard-sphere collision models, were also discussed. The energetic hard-sphere collision model was applied in the extraction of ion CCSs from high-resolution FT-ICR mass spectra. Discussions in the present study also apply to FT-Orbitraps and FT-quadrupole ion traps. PMID:25754983

  18. Using High-Resolution Field Measurements to Model Dune Kinematics in a Large Elongate Meander Bend.

    NASA Astrophysics Data System (ADS)

    Konsoer, K. M.; Rhoads, B. L.; Best, J.; Frias, C. E.; Abad, J. D.; Langendoen, E. J.

    2014-12-01

    Due to recent advances in hydroacoustic technology, such as the development of multibeam echo sounders, it is now possible to obtain highly accurate and detailed bathymetric data for river channels. These data provide the basis for detailed characterizations of bed form morphology ranging from individual ripples to composite dune fields. Theoretical models suggest that bed forms reach an equilibrium morphology based on hydraulic conditions during steady flow. However, at the scale of individual meander bends, bed form morphology will vary according to the local flow structure as influenced by overall bed morphology and planform curvature. Thus, the coevolution of flow structure, bed form morphology, and sediment transport should vary throughout a meander bend. This paper examines spatial variation in bed form characteristics and rates of bed form migration, and thus bed material transport, within a large, actively migrating, elongate meander loop. During a May 2013 flood event on Maier Bend, Wabash River (IL-IN, USA), repeat multibeam echo sounding surveys were conducted ~4 hours apart, providing estimates of dune celerity and volumetric rates of sediment transport at different locations around the bend. Three-dimensional velocity measurements, obtained using an acoustic Doppler current profiler, provide hydraulic data for evaluating interactions between flow structure and bed form morphology. Results show that bed form morphology is highly variable within the bend, ranging from barchans dunes on the upstream limb, 2D ripples across the point bar, and 3D composite dunes with wavelength of ~20 meters near the bend apex. Rates of dune celerity varied from 0.3 m/hr to 0.7 m/hr and were dependent on bed form geometry and local hydraulic conditions. The high-resolution data on flow and form are used to calibrate a 2D numerical model of sediment transport through the bend. Simulations using the calibrated model are used to evaluate the fluvial processes underlying

  19. High resolution minor and trace element measurements for mussel shells using LA-ICP-MS

    NASA Astrophysics Data System (ADS)

    Bian, N.; Paradis, G.; Martin, P. A.; Pfister, C. A.

    2011-12-01

    The successively deposited calcium carbonate layers in mollusk shells could offer high resolution archives of the environmental conditions the mollusk has experienced during its life. Previous studies have shown that the elemental composition of mollusk shells is related to environmental parameters. Understanding the high resolution environmental conditions recorded in the mollusk shells requires a reliable high resolution analytical method of the trace and minor element composition in the shells. In this study, we investigated three methods using different instrumental configurations to generate high resolution records/time series of a suite of minor/ trace elements in mussel shells (Mytilus californianus) using laser ablation sector field inductively coupled plasma mass spectrometry (LA-ICP-MS) and compared their advantages and disadvantages. The three methods include running the ablated sample with dry plasma, running the ablated sample with diluted nitric acid blank solution and running the ablated sample with spiked solution. We concluded that running the ablated material with the spiked solution could yield the most reproducible signal and accurate data for Mg/Ca, Sr/Ca, Ba/Ca, La/Ca, Ce/Ca and Nd/Ca. To better understand the features of the laser ablation analytical method, we did a series of tests, such as scanning at different speeds, different directions, and applying different sampling strategies and explored the possible complications that could be encountered in using the laser ablation analytical method. In addition, we compared the results from the micromilled samples analyzed by the solution based method to the those obtained from the laser ablation method. Our results demonstrate that applying the slow ablation speed and simultaneously introducing the spiked solution (i.e. along with the ablated sample in the He carrier gas) could yield high resolution and reproducible time series of element/Ca ratios throughout the life span of the mussel. An

  20. Measurement method for roll angular displacement with a high resolution by using diffraction gratings and a heterodyne interferometer

    SciTech Connect

    Tang, Shanzhi; Wang, Zhao; Gao, Jianmin; Guo, Junjie

    2014-04-15

    The roll angle measurement is difficult to be achieved directly using a typical commercial interferometer due to its low sensitivity in axial direction, where the axial direction is orthogonal to the plane of the roll angular displacement. A roll angle measurement method combined diffraction gratings with a laser heterodyne interferometer is discussed in this paper. The diffraction grating placed in the plane of a roll angular displacement and the interferometer arranged in the plane's orthogonal direction, constitute the measurement pattern for the roll angle with high resolution. The roll angular displacement, considered as the linear, can be tested precisely when the corresponding angle is very small. Using the proposed method, the angle roll measurement obtains the high resolution of 0.002{sup ″}. Experiment has proved its feasibility and practicability.

  1. Angle-resolved multioctave supercontinua from mid-infrared laser filaments.

    PubMed

    Mitrofanov, A V; Voronin, A A; Sidorov-Biryukov, D A; Mitryukovsky, S I; Rozhko, M V; Pugžlys, A; Fedotov, A B; Panchenko, V Ya; Baltuška, A; Zheltikov, A M

    2016-08-01

    Angle-resolved spectral analysis of a multioctave high-energy supercontinuum output of mid-infrared laser filaments is shown to provide a powerful tool for understanding intricate physical scenarios behind laser-induced filamentation in the mid-infrared. The ellipticity of the mid-infrared driver beam breaks the axial symmetry of filamentation dynamics, offering a probe for a truly (3+1)-dimensional spatiotemporal evolution of mid-IR pulses in the filamentation regime. With optical harmonics up to the 15th order contributing to supercontinuum generation in such filaments alongside Kerr-type and ionization-induced nonlinearities, the output supercontinuum spectra span over five octaves from the mid-ultraviolet deep into the mid-infrared. Full (3+1)-dimensional field evolution analysis is needed for an adequate understanding of this regime of laser filamentation. Supercomputer simulations implementing such analysis articulate the critical importance of angle-resolved measurements for both descriptive and predictive power of filamentation modeling. Strong enhancement of ionization-induced blueshift is shown to offer new approaches in filamentation-assisted pulse compression, enabling the generation of high-power few- and single-cycle pulses in the mid-infrared. PMID:27472598

  2. High-resolution real-time 3D shape measurement on a portable device

    NASA Astrophysics Data System (ADS)

    Karpinsky, Nikolaus; Hoke, Morgan; Chen, Vincent; Zhang, Song

    2013-09-01

    Recent advances in technology have enabled the acquisition of high-resolution 3D models in real-time though the use of structured light scanning techniques. While these advances are impressive, they require large amounts of computing power, thus being limited to using large desktop computers with high end CPUs and sometimes GPUs. This is undesirable in making high-resolution real-time 3D scanners ubiquitous in our mobile lives. To address this issue, this work describes and demonstrates a real-time 3D scanning system that is realized on a mobile device, namely a laptop computer, which can achieve speeds of 20fps 3D at a resolution of 640x480 per frame. By utilizing a graphics processing unit (GPU) as a multipurpose parallel processor, along with a parallel phase shifting technique, we are able to realize the entire 3D processing pipeline in parallel. To mitigate high speed camera transfer problems, which typically require a dedicated frame grabber, we make use of USB 3.0 along with direct memory access (DMA) to transfer camera images to the GPU. To demonstrate the effectiveness of the technique, we experiment with the scanner on both static geometry of a statue and dynamic geometry of a deforming material sample in front of the system.

  3. Instantaneous high-resolution multiple-frequency measurement system based on frequency-to-time mapping technique.

    PubMed

    Nguyen, Tuan A; Chan, Erwin H W; Minasian, Robert A

    2014-04-15

    A new microwave photonic instantaneous frequency measurement system that can simultaneously measure multiple-frequency signals while achieving very high resolution and wide frequency measurement range is presented. It is based on the frequency-to-time mapping technique implemented using a frequency shifting recirculating delay line loop and a narrowband optical filter realized by the in-fiber stimulated Brillouin scattering effect. Experimental results demonstrate the realization of a multiple-frequency measurement capability over a frequency range of 0.1-20 GHz that can be extended to 90 GHz, and with a measurement resolution of 250 MHz. PMID:24979008

  4. Angle resolved photoemission spectroscopy study on the non-saturate magnetoresistance material WTe2

    NASA Astrophysics Data System (ADS)

    Jiang, Juan; Niu, Xiaohai; Xie, Binping; Zhang, Tong; Feng, Donglai

    2015-03-01

    By performing high resolution angle-resolved photoemission spectroscopy, we obtain the detailed electronic structure of WTe2, which has an extremely large non-saturated magnetoresistance. Unlike the simple one electron and one hole pocket as expected, we resolved a rather complicated Fermi surface in WTe2. There is a hole pocket around the Brillouin zone center Γ, two hole pockets and two electron pockets along the tungsten chain direction. Thus the large magnetoresistance cannot be simply attributed to the electron-hole compensation, since this is based on a two carrier assumption model, the real case in WTe2 should be more complicated. Surprisingly, the circular dichroism ARPES result shows a strong intensity inversion between the data under the right-circular polarized light and the left-circular polarized light. This, indicates a proper different orbital angular momentum along the tungsten chain direction, which might also related to the different spin angular momentum since there're coupled with each other. Therefore, we propose that to fully understand the large magnetoresistance in WTe2, spin channel should also be involved where backscattering are forbidden under zero field.

  5. Extended-range grazing-incidence spectrometer for high-resolution extreme ultraviolet measurements on an electron beam ion trap

    SciTech Connect

    Beiersdorfer, P.; Magee, E. W.; Brown, G. V.; Träbert, E.; Widmann, K.; Hell, N.

    2014-11-15

    A high-resolution grazing-incidence grating spectrometer has been implemented on the Livermore electron beam ion traps for performing very high-resolution measurements in the soft x-ray and extreme ultraviolet region spanning from below 10 Å to above 300 Å. The instrument operates without an entrance slit and focuses the light emitted by highly charged ions located in the roughly 50 μm wide electron beam onto a cryogenically cooled back-illuminated charge-coupled device detector. The measured line widths are below 0.025 Å above 100 Å, and the resolving power appears to be limited by the source size and Doppler broadening of the trapped ions. Comparisons with spectra obtained with existing grating spectrometers show an order of magnitude improvement in spectral resolution.

  6. Spectroscopic Properties of Neodymium-Doped Yttrium Orthovanadate Single Crystals with High-Resolution Measurement

    NASA Astrophysics Data System (ADS)

    Sato, Yoichi; Taira, Takunori

    2002-10-01

    The absorption and fluorescence spectra of the neodymium-doped yttrium orthovanadate (Nd:YVO4) single crystal were investigated carefully. For the 808.8-nm absorption cross section, the published values varied between 18.4 and 25.6 × 10-20 cm2 for π-polarization. The authors evaluated this spectroscopic parameter with high resolution at 0.5 nm, and discovered 48.4 cm-1 at 808.8 nm even for the absorption of 1 at.% Nd3+-ion-doped YVO4 single crystal. This value is 1.3 times larger than the well-known value, and confirms that Nd:YVO4 is very suitable for microchip lasers, and that certain laser characteristics of Nd:YVO4 of previous works should be re-evaluated.

  7. Study of M1 and E1 excitations by high-resolution proton inelastic scattering measurement at forward angles

    SciTech Connect

    Tamii, A.; Adachi, T.; Hatanaka, K.; Hashimoto, H.; Kaneda, T.; Matsubara, H.; Okamura, H.; Sakemi, Y.; Shimizu, Y.; Tameshige, Y.; Yosoi, M.; Carter, J.; Dozono, M.; Fujita, H.; Fujita, Y.; Itoh, M.; Kawabata, T.; Nakanishi, K.; Sasamoto, Y.; Neumann-Cosel, P. von

    2007-06-13

    Experimental technique for measuring proton inelastic scattering with high-resolution at 295 MeV and at forward angles including zero degrees is described. The method is useful for extracting spin part of the M1 strength via nuclear excitation as well as E1 strength via Coulomb excitation. An excitation energy resolution of 20 keV, good scattering angle resolution, and low background condition have been achieved. The experimental technique was applied for several sd and pf shell nuclei.

  8. High-Resolution UV Relay Lens for Particle Size Distribution Measurements Using Holography

    SciTech Connect

    Malone, Robert M.; Capelle, Gene A.; Frogget, Brent C.; Grover, Mike; Kaufman, Morris I.; Pazuchanics, Peter; Sorenson, Danny S.; Stevens, Gerald D.; Tibbits, Aric; Turley, William D.

    2008-08-29

    Shock waves passing through a metal sample can produce ejecta particulates at a metal-vacuum interface. Holography records particle size distributions by using a high-power, short-pulse laser to freeze particle motion. The sizes of the ejecta particles are recorded using an in-line Fraunhofer holography technique. Because the holographic plate would be destroyed in an energetic environment, a high-resolution lens has been designed to relay the interference fringes to a safe environment. Particle sizes within a 12-mm-diameter, 5-mm-thick volume are recorded onto holographic film. To achieve resolution down to 0.5 μm, ultraviolet laser (UV) light is needed. The design and assembly of a nine-element lens that achieves >2000 lp/mm resolution and operates at f/0.89 will be described. To set up this lens system, a doublet lens is temporarily attached that enables operation with 532-nm laser light and 1100 lp/mm resolution. Thus, the setup and alignment are performed with green light, but the dynamic recording is done with UV light. During setup, the 532-nm beam provides enough focus shift to accommodate the placement of a resolution target outside the ejecta volume; this resolution target does not interfere with the calibrated wires and pegs surrounding the ejecta volume. A television microscope archives images of resolution patterns that prove that the calibration wires, interference filter, holographic plate, and relay lenses are in their correct positions. Part of this lens is under vacuum, at the point where the laser illumination passes through a focus. Alignment and tolerancing of this high-resolution lens will be presented, and resolution variation through the 5-mm depth of field will be discussed.

  9. High-Resolution UV Relay Lens for Particle Size Distribution Measurements Using Holography

    SciTech Connect

    Robert M. Malone, Brent C. Frogget, Morris I. Kaufman, Aric Tibbits, Gene A. Capelle, Mike Grover, Gerald D. Stevens, William D. Turley

    2008-03-01

    Shock waves passing through a metal sample can produce ejecta particulates at a metal-vacuum interface. Holography records particle size distributions by using a highpower, short-pulse laser to freeze particle motion. The sizes of the ejecta particles are recorded using an in-line Fraunhofer holography technique. Because the holographic plate would be destroyed in this energetic environment, a high-resolution lens has been designed to relay the interference fringes to a safe environment. Particle sizes within a 12-mm-diameter, 5-mm-thick volume are recorded on holographic film. To achieve resolution down to 0.5 microns, ultraviolet (UV) light (in this case supplied by a tripled Nd:YAG laser) is needed. The design and assembly of a nine-element lens that achieves >2000 lp/mm resolution and operates at f/0.85 will be described. To set up this lens system, a doublet lens is temporarily attached that enables operation with 532-nm (green) light and 1100 lp/mm resolution. Thus, the setup and alignment is performed with green light, but the dynamic recording is done with UV light. During setup, the 532-nm beam provides enough focus shift to accommodate the placement of a resolution pattern outside the ejecta volume; this resolution pattern does not interfere with the calibrated wires and pegs surrounding the ejecta volume. A television microscope archives images of resolution patterns that prove that the calibration wires, interference filter, holographic plate, and relay lenses are in their correct positions. Part of this lens is under vacuum, at the point where the laser illumination passes through a focus. Alignment and tolerancing of this high-resolution lens will be presented, and resolution variation through the 5-mm depth of field will be discussed.

  10. Substrate interactions with suspended and supported monolayer MoS2: Angle-resolved photoemission spectroscopy

    DOE PAGESBeta

    Jin, Wencan; Yeh, Po -Chun; Zaki, Nader; Zhang, Datong; Liou, Jonathan T.; Dadap, Jerry I.; Barinov, Alexey; Yablonskikh, Mikhail; Sadowski, Jerzy T.; Sutter, Peter; et al

    2015-03-17

    We report the directly measured electronic structure of exfoliated monolayer molybdenum disulfide (MoS₂) using micrometer-scale angle-resolved photoemission spectroscopy. Measurements of both suspended and supported monolayer MoS₂ elucidate the effects of interaction with a substrate. Thus, a suggested relaxation of the in-plane lattice constant is found for both suspended and supported monolayer MoS₂ crystals. For suspended MoS₂, a careful investigation of the measured uppermost valence band gives an effective mass at Γ¯ and Κ¯ of 2.00m₀ and 0.43m₀, respectively. We also measure an increase in the band linewidth from the midpoint of Γ¯Κ¯ to the vicinity of Κ¯ and briefly discussmore » its possible origin.« less

  11. Angle-resolved photoemission spectroscopy (ARPES) studies of cuprate superconductors

    SciTech Connect

    Palczewski, Ari Deibert

    2010-01-01

    This dissertation is comprised of three different angle-resolved photoemission spectroscopy (ARPES) studies on cuprate superconductors. The first study compares the band structure from two different single layer cuprates Tl2Ba2CuO6+δ (Tl2201) Tc, max ≈ 95 K and (Bi 1.35Pb0.85)(Sr1.47La0.38)CuO6+δ (Bi2201) Tc, max ≈ 35 K. The aim of the study was to provide some insight into the reasons why single layer cuprate's maximum transition temperatures are so different. The study found two major differences in the band structure. First, the Fermi surface segments close to (π,0) are more parallel in Tl2201 than in Bi2201. Second, the shadow band usually related to crystal structure is only present in Bi2201, but absent in higher Tc Tl2201. The second study looks at the different ways of doping Bi2Sr2CaCu2O8+δ (Bi2212) in-situ by only changing the post bake-out vacuum conditions and temperature. The aim of the study is to systematically look into the generally overlooked experimental conditions that change the doping of a cleaved sample in ultra high vacuum (UHV) experiments. The study found two major experimental facts. First, in inadequate UHV conditions the carrier concentration of Bi2212 increases with time, due to the absorption of oxygen from CO2/CO molecules, prime contaminants present in UHV systems. Second, in a very clean UHV system at elevated temperatures (above about 200 K), the carrier concentration decreases due to the loss of oxygen atoms from the Bi-O layer. The final study probed the particle-hole symmetry of the pseudogap phase in high temperature superconducting cuprates by looking at the thermally excited bands above the Fermi level. The data showed a particle-hole symmetric pseudogap which symmetrically closes away from the nested FS before the node. The data is consistent

  12. A high-resolution analyser for the measurement of ammonium in oligotrophic seawater

    NASA Astrophysics Data System (ADS)

    Abi Kaed Bey, Samer K.; Connelly, Douglas P.; Legiret, François-Eric; Harris, Andy J. K.; Mowlem, Matthew C.

    2011-10-01

    In this work, we describe a high-resolution fluorometric shipboard analyser and an improved method to determine NH{4/+} in oligotrophic seawater. The limit of detection is <5 nM, calculated with 95% confidence level using the weighted regression line applied to the standard addition method using real samples prepared with low nutrient seawater from the Atlantic. The results are summarised and cross-compared with spiked artificial seawater (ASW) and spiked Milli-Q water samples. The analyser has a precision of ±1-4% with a high performance over a wide range from 5 nM to 25 μM. The methodology of NH{4/+} analysis is based on the fluorescent product formed between o-pthaldialdehyde and NH{4/+} in the presence of sulfite. Due to the high resolution of the developed system, we were able to study in depth the sensitivity of the method to salinity, amines, amino acids and potential interferences from particles/algae. The method was found to be sensitive to salinity variations, reducing the signal by up to 85% at 5 nM; this effect decreased at higher concentrations of ammonium. It was noted that the interference from amines at low concentrations was negligible; however, at either high amino acid or high amine concentrations, the signal was depressed. To test for the effect of particles on the system, the system was tested with samples containing phytoplankton ( Dunaliella primolecta) cells at different concentrations prepared with ASW to simulate the effect of a phytoplankton bloom. This experiment assessed the potential impact of both particles and other potential fluorescence interferences from cells and/or ammonium leaching from cells. This experiment showed that a phytoplankton bloom could potentially have an impact of up to 12% on the signal of interest. Thus, we propose that this method is suitable for oligotrophic environments rather than coastal and eutrophic environments. The reagent was found to be stable for 17 days and standards of 1 μM were stable for 6

  13. Radioactivity of a Rock Profile from Rio do Rasto Formation Measured by High Resolution Gamma Spectrometry

    NASA Astrophysics Data System (ADS)

    Bastos, Rodrigo O.; Appoloni, Carlos R.; Pinese, José P. P.

    2011-08-01

    Natural occurring radionuclides are present in different concentrations in sedimentary rocks. Generally, their distribution correlates reasonably with their geo-physicochemical behavior during sediment deposition and rock consolidation. This fact permits to study some geological characteristics of the rocks by analyzing the radionuclide distribution in the rocks, as it might reflect the origin of the sediments, the depositional environment, and more recent events such as weathering and erosion. In this work, rocks from an exposed profile of the Rio do Rasto Formation were collected and analyzed in laboratory by high resolution gamma spectrometry for 226Ra, 232Th and 40K determination. It was employed a standard gamma ray spectrometry electronic chain, with a 66% relative efficiency HPGe detector. The efficiency calibration, as well as its validation, was accomplished with eight International Atomic Energy Agency certified samples. The outcrop exposes layers of sandstone and siltstone and, secondarily, claystone, with varying colors (gray, red and green). The rocks were collected along this profile, each of them was dried in the open air during 48 hours, grounded, sieved through 4 mm mesh and sealed in cylindrical recipients. The 226Ra, 232Th and 40K activity concentrations are presented, their distribution and the possible relations among activities are analyzed. The general pattern of radionuclides distribution respects well the hypotheses on geo-physicochemical behavior of radioactive elements.

  14. High resolution measures of polarization and color of selected lunar areas

    NASA Technical Reports Server (NTRS)

    Riley, L. A.; Hall, J. S.

    1972-01-01

    High resolution observations of intensity, color (UBV) and polarization were obtained with scanning techniques for a number of lunar areas of special interest, including boundaries of some of the brightest and darkest lunar regions, certain Apollo landing sites and prominent craters. Two dimensional raster scans of colors were obtained for Alphonsus, Aristarchus, and Herodotus. The degree of polarization for any given phase angle appears to be roughly indicative of age. The darker younger mare surface are more highly polarized than the lighter and older mare surfaces, which appear to be more contaminated by lighter material from the highlands or by ray material thrown out from fresh craters. All mare surfaces are more highly polarized than the still older and lighter terra regions surrounding the maria. The very oldest craters are either dark-floored and show polarization characteristics similar to those of the mare surfaces, or if located in the highlands, they are less and less distinguishable from the highland background with greater age, and show the general highland polarization characteristics.

  15. High-resolution isotope measurements resolve rapid ecohydrological dynamics at the soil-plant interface.

    PubMed

    Volkmann, Till H M; Haberer, Kristine; Gessler, Arthur; Weiler, Markus

    2016-05-01

    Plants rely primarily on rainfall infiltrating their root zones - a supply that is inherently variable, and fluctuations are predicted to increase on most of the Earth's surface. Yet, interrelationships between water availability and plant use on short timescales are difficult to quantify and remain poorly understood. To overcome previous methodological limitations, we coupled high-resolution in situ observations of stable isotopes in soil and transpiration water. We applied the approach along with Bayesian mixing modeling to track the fate of (2) H-labeled rain pulses following drought through soil and plants of deciduous tree ecosystems. We resolve how rainwater infiltrates the root zones in a nonequilibrium process and show that tree species differ in their ability to quickly acquire the newly available source. Sessile oak (Quercus petraea) adjusted root uptake to vertical water availability patterns under drought, but readjustment toward the rewetted topsoil was delayed. By contrast, European beech (Fagus sylvatica) readily utilized water from all soil depths independent of water depletion, enabling faster uptake of rainwater. Our results demonstrate that species-specific plasticity and responses to water supply fluctuations on short timescales can now be identified and must be considered to predict vegetation functional dynamics and water cycling under current and future climatic conditions. PMID:26864434

  16. Variability of the North Atlantic Current: high resolution model data versus in situ measurements

    NASA Astrophysics Data System (ADS)

    Breckenfelder, Tilia; Rhein, Monika; Roessler, Achim; Behrens, Erik; Böning, Claus; Biastoch, Arne; Mertens, Christian

    2015-04-01

    The North Atlantic Current (NAC) provides an important heat source for the relatively warm winters in Western Europe by bringing warm and salty tropical/subtropical water into the subpolar gyre of the North Atlantic. The NAC is the northward extension of the Gulfstream and its warm and salty water form the warm upper branch of the Atlantic Meridional Overturning Circulation (AMOC). The NAC crosses the Mid-Atlantic Ridge (MAR) via the Charlie-Gibbs, Faraday and Maxwell Fracture Zones between 47° and 53°N. Along that section an array of four inverted echo sounders with bottom pressure sensors (PIES) are deployed since 2006 and combined with altimetry to quantify the NAC transport and its variability. The observed transport time series is compared to the high resolution output of the VIKING20 model, a 1/20° North Atlantic model which is embedded in a global model of 1/4° resolution (ORCA25) via a two-way nesting. We compare the horizontal and vertical flow fields, the mean transport and the variability as well as the water mass characteristics.

  17. Using high-resolution phosphorus data to investigate mitigation measures in headwater river catchments

    NASA Astrophysics Data System (ADS)

    Campbell, J. M.; Jordan, P.; Arnscheidt, J.

    2015-01-01

    This study reports the use of high-resolution water quality monitoring to assess the influence of changes in land use management on total phosphorus (TP) transfers in two 5 km2 agricultural sub-catchments. Specifically, the work investigates the issue of agricultural soil P management and subsequent diffuse transfers at high river flows over a 5-year timescale. The work also investigates the phenomenon of low flow P pollution from septic tank systems (STSs) and mitigation efforts - a key concern for catchment management. Results showed an inconsistent response to soil P management over 5 years with one catchment showing a convergence to optimum P concentrations and the other an overall increase. Both catchments indicated an overall increase in P concentration in defined high flow ranges. Low flow P concentration showed little change or higher P concentrations in defined low flow ranges despite replacement of defective systems and this is possibly due to a number of confounding reasons including increased housing densities due to new-builds. The work indicates fractured responses to catchment management advice and mitigation and that the short to medium term may be an insufficient time to expect the full implementation of policies (here defined as convergence to optimum soil P concentration and mitigation of STSs) and also to gauge their effectiveness.

  18. Using high-resolution phosphorus data to investigate mitigation measures in headwater river catchments

    NASA Astrophysics Data System (ADS)

    Campbell, J. M.; Jordan, P.; Arnscheidt, J.

    2014-09-01

    This study reports the use of high resolution water quality monitoring to assess the influence of changes in landuse management on total phosphorus (TP) transfers in two 5 km2 agricultural sub-catchments. Specifically, the work investigates the "wicked problem" of agricultural soil P management and subsequent diffuse transfers at high river flows over a five year timescale. The work also investigates the phenomenon of low flow P pollution from septic tank systems (STS) and mitigation efforts - here termed the "filthy issue" of rural catchment management. Results showed an inconsistent response to soil P management over five years with one catchment showing a convergence to optimum P concentrations and the other an overall increase. Both catchments indicated an overall increase in P concentration in defined high flow ranges. Low flow P concentration showed little change or higher P concentrations in defined low flow ranges despite replacement of defective systems and this is possibly due to a number of confounding reasons including increased housing densities due to new-builds. The work indicates fractured responses to catchment management advice and mitigation and that the short to medium term may be an insufficient time to expect the full implementation of policies (here defined as convergence to optimum soil P concentration and mitigation of STS) and also to gauge their effectiveness.

  19. A brief update of angle-resolved photoemission spectroscopy on a correlated electron system

    SciTech Connect

    Lee, W.S.

    2010-02-24

    In this paper, we briefly summarize the capabilities of state-of-the-art angle-resolved photoemission spectroscopy (ARPES) in the field of experimental condensed matter physics. Due to the advancement of the detector technology and the high flux light sources, ARPES has become a powerful tool to study the low energy excitations of solids, especially those novel quantum materials in which many-body physics are at play. To benchmark today's state-of-the-art ARPES technique, we demonstrate that the precision of today's ARPES has advanced to a regime comparable to the bulk-sensitive de Haas-van Alphen (dHvA) measurements. Finally, as an example of new discoveries driven by the advancement of the ARPES technique, we summarize some of our recent ARPES measurements on underdoped high-T{sub c} superconducting cuprates, which have provided further insight into the complex pseudogap problem.

  20. Evaluation of High-Resolution Ocean Surface Vector Winds Measured by QuikSCAT Scatterometer in Coastal Regions

    NASA Technical Reports Server (NTRS)

    Tang, Wenqing; Liu, W. Timothy; Stiles, Bryan W.

    2004-01-01

    The SeaWinds scatterometer onboard QuikSCAT covers approximately 90% of the global ocean under clear and cloudy condition in 24 h, and the standard data product has 25-km spatial resolution. Such spatial resolution is not sufficient to resolve small-scale processes, especially in coastal oceans. Based on range-compressed normalized backscatter and a modified wind retrieval algorithm, a coastal wind dataset at 12.5-km resolution was produced. Even with larger error, the high-resolution winds, in medium to high strength, would still be useful over coastal ocean. Using measurements from moored buoys from the National Buoy Data Center, the high-resolution QuikSCAT wind data are found to have similar accuracy as standard data in the open ocean. The accuracy of both high- and standard-resolution winds, particularly in wind directions, is found to degrade near shore. The increase in error is likely caused by the inadequacy of the geophysical model function/ambiguity removal scheme in addressing coastal conditions and light winds situations. The modified algorithm helps to bring the directional accuracy of the high-resolution winds to the accuracy of the standard-resolution winds in near-shore regions, particularly in the nadir and far zones across the satellite track.

  1. High-resolution measurements of the K-MM radiative Auger effect in medium-mass atoms

    NASA Astrophysics Data System (ADS)

    Herren, Ch.; Dousse, J.-Cl.

    1996-02-01

    High-resolution measurements of the Kβ1,3 low-energy satellites of 42Mo, 44Ru, 46Pd, 48Cd, and 50Sn were performed. The photoinduced x-ray spectra were measured with a transmission-type bent-crystal spectrometer. Particular groups of K-MM radiative Auger effect (RAE) transitions could be identified. The intensity ratios I(K-MM RAE) / I(Kβ13) were extracted. They are compared to relativistic Hartree-Fock theoretical predictions of Scofield. The experimental energies of the RAE edges are compared to calculated Auger transition energies. The present experiment provides experimental RAE results for solid elements with Z>=42.

  2. Surface structure of imidazolium-based ionic liquids: Quantitative comparison between simulations and high-resolution RBS measurements

    NASA Astrophysics Data System (ADS)

    Nakajima, Kaoru; Nakanishi, Shunto; Lísal, Martin; Kimura, Kenji

    2016-03-01

    Elemental depth profiles of 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([CnMIM][TFSI], n = 4, 6, 8) are measured using high-resolution Rutherford backscattering spectroscopy (HRBS). The profiles are compared with the results of molecular dynamics (MD) simulations. Both MD simulations and HRBS measurements show that the depth profiles deviate from the uniform stoichiometric composition in the surface region, showing preferential orientations of ions at the surface. The MD simulations qualitatively reproduce the observed HRBS profiles but the agreement is not satisfactory. The observed discrepancy is ascribed to the capillary waves. By taking account of the surface roughness induced by the capillary waves, the agreement becomes almost perfect.

  3. Measurement of low radioactivity background in a high voltage cable by high resolution inductively coupled plasma mass spectrometry

    SciTech Connect

    Vacri, M. L. di; Nisi, S.; Balata, M.

    2013-08-08

    The measurement of naturally occurring low level radioactivity background in a high voltage (HV) cable by high resolution inductively coupled plasma mass spectrometry (HR ICP MS) is presented in this work. The measurements were performed at the Chemistry Service of the Gran Sasso National Laboratory. The contributions to the radioactive background coming from the different components of the heterogeneous material were separated. Based on the mass fraction of the cable, the whole contamination was calculated. The HR ICP MS results were cross-checked by gamma ray spectroscopy analysis that was performed at the low background facility STELLA (Sub Terranean Low Level Assay) of the LNGS underground lab using HPGe detectors.

  4. Determination of Spectroscopic Properties of Atmospheric Molecules from High Resolution Vacuum Ultraviolet Cross Section and Wavelength Measurements

    NASA Technical Reports Server (NTRS)

    Parkinson, W. H.; Yoshino, K.

    1997-01-01

    An account is given of progress during the period 8/l/96-7/31/97 on work on (a) cross section measurements of O2 S-R using a Fourier transform spectrometer (FTS) at the Photon Factory in Japan; (b) the determination of the predissociation linewidths of the Schumann-Runge bands (S-R) of 02; (c) cross section measurements of 02 Herzberg bands using a Fourier transform spectrometer (FTS) at Imperial College; and (d) cross section measurements of H2O in the wavelength region 120-188 nm. The experimental investigations are effected at high resolution with a 6.65 m scanning spectrometer and with the Fourier transform spectrometer. Below 175 nm, synchrotron radiation is most suitable for cross section measurements in combination with spectrometers at the Photon Factory Japan. Cross section measurements of the Doppler limited bands depend on using the very high resolution, available with the Fourier transform spectrometer, (0.025/cm resolution). All of these spectroscopic measurements are needed for accurate calculations of the production of atomic oxygen, the penetration of solar radiation into the Earth's atmosphere, and photochemistry of minor molecules.

  5. Evidencing the need for high spatial resolution in angle-resolved photoemission experiments

    NASA Astrophysics Data System (ADS)

    Joucken, Frédéric; Reckinger, Nicolas; Lorcy, Stéphane; Avila, José; Chen, Chaoyu; Lagoute, Jérôme; Colomer, Jean-François; Ghijsen, Jacques; Asensio, Maria Carmen; Sporken, Robert

    2016-06-01

    Angle-resolved photoemission spectroscopy (ARPES) is the most direct tool to measure the electronic structure of materials. In particular, fine features of the spectra can be analyzed for evaluating the electron self-energy. Owing to a setup allowing ARPES investigation with submicron resolution and state-of-the-art energy and momentum resolution, we show here first that ARPES spectra of pristine and virtually undoped monolayer graphene acquired on a small spot do not display manifestations of self-energy. We next demonstrate that, although the region of the sample investigated is a unique graphene domain, it displays faint spatial inhomogeneity, both in its crystallographic orientation and its thickness, which is undetectable with conventional ARPES but renders the spectra improper for self-energy extraction. These results indicate that care should be taken when analyzing ARPES spectra obtained with poor spatial resolution.

  6. Angle-resolved photoemission study on potential topological insulator ZrTe5

    NASA Astrophysics Data System (ADS)

    Xiong, Hongyu; Sobota, Jonathan; Yang, Shuolong; Leuenberger, Dominik; Soifer, Hadas; Chen, Yan-Feng; Han, Xu; Yu, Si-Yuan; Lu, Ming-Hui; Hashimoto, Makoto; Lu, Donghui; Kirchmann, Patrick; Shen, Zhi-Xun

    ZrTe5 is a layered-structure material which is predicted to exhibit the quantum spin hall effect in its monolayer limit. Bulk ZrTe5 material is of scientific interest as well, as it might lie within the transition boundary between weak and strong topological insulator. We are using angle-resolved photoemission spectroscopy (ARPES) to investigate the band structure of bulk ZrTe5. Synchrotron data with varied photon energies shows little kz dependence, which indicates a quasi-two-dimensional band structure; in addition, we observe circular dichroism, which suggests possible spin polarization. We are also working on time-resolved ARPES measurements, hoping to reveal the band structure above the Fermi level, which might give information about the material's topological properties.

  7. Modeling angle-resolved photoemission of graphene and black phosphorus nano structures

    PubMed Central

    Park, Sang Han; Kwon, Soonnam

    2016-01-01

    Angle-resolved photoemission spectroscopy (ARPES) data on electronic structure are difficult to interpret, because various factors such as atomic structure and experimental setup influence the quantum mechanical effects during the measurement. Therefore, we simulated ARPES of nano-sized molecules to corroborate the interpretation of experimental results. Applying the independent atomic-center approximation, we used density functional theory calculations and custom-made simulation code to compute photoelectron intensity in given experimental setups for every atomic orbital in poly-aromatic hydrocarbons of various size, and in a molecule of black phosphorus. The simulation results were validated by comparing them to experimental ARPES for highly-oriented pyrolytic graphite. This database provides the calculation method and every file used during the work flow. PMID:27164313

  8. Angle-resolved Beutler-Fano profile and dynamics for the predissociation of H2

    NASA Astrophysics Data System (ADS)

    Meng, Qingnan; Wang, Jie; Mo, Yuxiang

    2016-05-01

    The asymmetric photoabsorption line profile (Beutler-Fano profile) arising from two interacting channels has applications in atomic, molecular, and condensed matter physics. In this work, the angle-resolved and fully-rotationally-resolved Beutler-Fano profiles for the predissociation of H2,H2+h v →H ( 1 s )+H ( 2 s )/H (2 p ) , have been measured. It is found that the Beutler-Fano profiles display different shapes for the fragments H(2 s ,2 p ) recoiling at the parallel and perpendicular directions relative to the polarization direction of the dissociation laser. Tuning the excitation photon energy from the resonance center to the lower energies within the Beutler-Fano profile, the branching ratios H(2 s )/[H(2 s )+H(2 p )] decrease, and the fragment angular distributions change in a trend indicating the presence of more components of direct dissociation channels in comparison with the predissociation channel.

  9. Tunable vacuum ultraviolet laser based spectrometer for angle resolved photoemission spectroscopy

    SciTech Connect

    Jiang, Rui; Mou, Daixiang; Wu, Yun; Huang, Lunan; Kaminski, Adam; McMillen, Colin D.; Kolis, Joseph; Giesber, Henry G.; Egan, John J.

    2014-03-15

    We have developed an angle-resolved photoemission spectrometer with tunable vacuum ultraviolet laser as a photon source. The photon source is based on the fourth harmonic generation of a near IR beam from a Ti:sapphire laser pumped by a CW green laser and tunable between 5.3 eV and 7 eV. The most important part of the set-up is a compact, vacuum enclosed fourth harmonic generator based on potassium beryllium fluoroborate crystals, grown hydrothermally in the US. This source can deliver a photon flux of over 10{sup 14} photon/s. We demonstrate that this energy range is sufficient to measure the k{sub z} dispersion in an iron arsenic high temperature superconductor, which was previously only possible at synchrotron facilities.

  10. Modeling angle-resolved photoemission of graphene and black phosphorus nano structures.

    PubMed

    Park, Sang Han; Kwon, Soonnam

    2016-01-01

    Angle-resolved photoemission spectroscopy (ARPES) data on electronic structure are difficult to interpret, because various factors such as atomic structure and experimental setup influence the quantum mechanical effects during the measurement. Therefore, we simulated ARPES of nano-sized molecules to corroborate the interpretation of experimental results. Applying the independent atomic-center approximation, we used density functional theory calculations and custom-made simulation code to compute photoelectron intensity in given experimental setups for every atomic orbital in poly-aromatic hydrocarbons of various size, and in a molecule of black phosphorus. The simulation results were validated by comparing them to experimental ARPES for highly-oriented pyrolytic graphite. This database provides the calculation method and every file used during the work flow. PMID:27164313

  11. Angle-resolved spin wave band diagrams of square antidot lattices studied by Brillouin light scattering

    SciTech Connect

    Gubbiotti, G.; Tacchi, S.; Madami, M.; Carlotti, G.; Ding, J.; Adeyeye, A. O.

    2015-06-29

    The Brillouin light scattering technique has been exploited to study the angle-resolved spin wave band diagrams of squared Permalloy antidot lattice. Frequency dispersion of spin waves has been measured for a set of fixed wave vector magnitudes, while varying the wave vector in-plane orientation with respect to the applied magnetic field. The magnonic band gap between the two most dispersive modes exhibits a minimum value at an angular position, which exclusively depends on the product between the selected wave vector magnitude and the lattice constant of the array. The experimental data are in very good agreement with predictions obtained by dynamical matrix method calculations. The presented results are relevant for magnonic devices where the antidot lattice, acting as a diffraction grating, is exploited to achieve multidirectional spin wave emission.

  12. Preparation of layered thin film samples for angle-resolved photoemission spectroscopy

    SciTech Connect

    Harrison, S. E.; Zhou, B.; Huo, Y.; Harris, J. S.; Pushp, A.; Kellock, A. J.; Parkin, S. S. P.; Chen, Y.; Hesjedal, T.

    2014-09-22

    Materials with layered van der Waals crystal structures are exciting research topics in condensed matter physics and materials science due to outstanding physical properties associated with their strong two dimensional nature. Prominent examples include bismuth tritelluride and triselenide topological insulators (TIs), which are characterized by a bulk bandgap and pairwise counter-propagating spin-polarized electronic surface states. Angle-resolved photoemission spectroscopy (ARPES) of ex-situ grown thin film samples has been limited by the lack of suitable surface preparation techniques. We demonstrate the shortcomings of previously successful conventional surface preparation techniques when applied to ternary TI systems which are susceptible to severe oxidation. We show that in-situ cleaving is a simple and effective technique for preparation of clean surfaces on ex-situ grown thin films for high quality ARPES measurements. The method presented here is universally applicable to other layered van der Waals systems as well.

  13. Angle resolved XPS of monomolecular layer of 5-chlorobenzotriazole on oxidized metallic surface

    NASA Astrophysics Data System (ADS)

    Kazansky, L. P.; Selyaninov, I. A.; Kuznetsov, Yu. I.

    2012-10-01

    Angle resolved XPS is used to study adsorption of 5-chlorobenzotriazole (5-chloroBTAH) on surfaces of the oxidized metals: mild steel, copper and zinc from borate buffer solution (pH 7.4). It is shown that for the metals studied the 5-chloroBTA anions, when adsorbed, form a monomolecular layer whose thickness is ∼6 Å comparable with the size of BTA. As XPS evidences adsorption proceeds with deprotonation of 5-chloroBTAH and formation of the coordination bonds between the lone pair of nitrogens and cation of a metal. Measuring XPS at two different angles unequivocally points out almost vertical arrangement of the anions toward the sample surface, when chlorine atoms form outmost virtual layer.

  14. Evaluating high resolution GRACE solutions against in situ measurements in the Three-Gorge Reservoir

    NASA Astrophysics Data System (ADS)

    De Linage, C.; Bettadpur, S.; Famiglietti, J. S.

    2012-12-01

    Wang et al (2011) showed that, when compared to in situ data, the total volume change associated with the impoundment of the Three-Gorge Reservoir between April 2002 and May 2010 could be retrieved with a 3-km3 (14%) error by the GRACE-CSR Release 04 solutions at 3.5° (max. harmonic degree 51) resolution after correlated errors were removed. However, the retrieved total volume change suffered from low spatial resolution and incorrect spatial localization. A larger volume increase was found in GRACE compared to in situ data during the last impoundment which was attributable to seepage into the underlying aquifer. In this study, we analyze the new CSR-Release 05 monthly solutions for 2004-2010. We also generate high resolution (1°, max. degree 180) mean solutions computed before and after the first and last impoundments for both Release 04 and Release 05. Correlated errors are removed using the decorrelation filter suggested by Swenson and Wahr (2006). We find a better agreement with RL05 (r2=0.66, MAD=4.30 km3) than with RL04 monthly solutions (r2=0.50, MAD=4.95 km3), and find even larger volume increase during the last impoundment (5-8 km3 difference vs 4-6 km3), strengthening our initial hypothesis of groundwater recharge. We find that 1° resolution mean solutions need to be truncated at max. degree 80 (2.5°) to reduce the impact of noise. A better spatial concentration is then obtained although the total volume change is now underestimated compared to in situ data. Finally, the damping effect of the decorrelation filter is investigated by forward modeling of total volume change using the 3" SRTM DEM. As an alternative, we apply the spatio-spectral localization technique based on Slepian functions (Simons 2006) to improve the signal-to-noise ratio. The contribution of regional hydrology is also considered via global hydrological model predictions.

  15. Structure and interactions of fluid phospholipid bilayers measured by high-resolution X-ray scattering

    NASA Astrophysics Data System (ADS)

    Petrache, Horia Iosif

    The topic of this work is the biologically relevant fluid phase of phosphatidylcholine lipid bilayers. A first goal is the determination of the average bilayer structure using low-angle X-ray scattering from multilamellar lipid vesicles (MLVs). The MLVs are smectic liquid crystals, for which interbilayer correlations decay algebraically. Consequently, the smectic Bragg peaks have power low tails, with the exponent related to the bilayer fluctuations. The analysis of such peaks requires good instrumental resolution and a sophisticated (and equally good) scattering theory. The high resolution is achieved at the F3 station at CHESS. The scattering theory is an improved version of the modified Caillé theory being developed in our laboratory. Data fitting gives the three pieces of information carried by the scattering peaks: position, amplitude, and power-law exponent. The position and the amplitude (form factor) are used to determine the bilayer structure. The power-law exponent is converted into mean square fluctuations in the interbilayer water spacing. This opens a new window on interbilayer interactions which is the second goal of this work. The fundamental issue of interbilayer interactions is addressed both experimentally and theoretically. We obtain the interbilayer water spacing fluctuation σ, as well as the traditional osmotic pressure P, both as functions of the lamellar repeat spacing D and the aqueous separation a. We show theoretically how to obtain the functional form of the fluctuational free energy from the a data, which is then determined to within a factor that depends upon the bending modulus, Kc. The resulting functional form determined from experimental data has an exponential decay rather than the power law decay that applies for hard confinement in the large a regime, thereby showing that a theory of soft confinement is necessary. The existing theory of soft confinement predicts an exponential decay, but with a smaller decay length λfl than we

  16. Two-photon high-resolution measurement of partial pressure of oxygen in cerebral vasculature and tissue.

    PubMed

    Sakadzić, Sava; Roussakis, Emmanuel; Yaseen, Mohammad A; Mandeville, Emiri T; Srinivasan, Vivek J; Arai, Ken; Ruvinskaya, Svetlana; Devor, Anna; Lo, Eng H; Vinogradov, Sergei A; Boas, David A

    2010-09-01

    Measurements of oxygen partial pressure (pO(2)) with high temporal and spatial resolution in three dimensions is crucial for understanding oxygen delivery and consumption in normal and diseased brain. Among existing pO(2) measurement methods, phosphorescence quenching is optimally suited for the task. However, previous attempts to couple phosphorescence with two-photon laser scanning microscopy have faced substantial difficulties because of extremely low two-photon absorption cross-sections of conventional phosphorescent probes. Here we report to our knowledge the first practical in vivo two-photon high-resolution pO(2) measurements in small rodents' cortical microvasculature and tissue, made possible by combining an optimized imaging system with a two-photon-enhanced phosphorescent nanoprobe. The method features a measurement depth of up to 250 microm, sub-second temporal resolution and requires low probe concentration. The properties of the probe allowed for direct high-resolution measurement of cortical extravascular (tissue) pO(2), opening many possibilities for functional metabolic brain studies. PMID:20693997

  17. Two-photon high-resolution measurement of partial pressure of oxygen in cerebral vasculature and tissue

    PubMed Central

    Sakadžić, Sava; Roussakis, Emmanuel; Yaseen, Mohammad A.; Mandeville, Emiri T.; Srinivasan, Vivek J.; Arai, Ken; Ruvinskaya, Svetlana; Devor, Anna; Lo, Eng H.; Vinogradov, Sergei A.; Boas, David A.

    2010-01-01

    The ability to measure oxygen partial pressure (pO2) with high temporal and spatial resolution in three dimensions is crucial for understanding oxygen delivery and consumption in normal and diseased brain. Among existing pO2 measurement methods, phosphorescence quenching is optimally suited for the task. However, previous attempts to couple phosphorescence with two-photon laser scanning microscopy have faced substantial difficulties because of extremely low two-photon absorption cross-sections of conventional phosphorescent probes. Here, we report the first practical in vivo two-photon high-resolution pO2 measurements in small rodents’ cortical microvasculature and tissue, made possible by combining an optimized imaging system with a two-photon-enhanced phosphorescent nanoprobe. The method features a measurement depth of up to 250 µm, sub-second temporal resolution and requires low probe concentration. Most importantly, the properties of the probe allowed for the first direct high-resolution measurement of cortical extravascular (tissue) pO2, opening numerous possibilities for functional metabolic brain studies. PMID:20693997

  18. Application of high-resolution spectral absorbance measurements to determine dissolved organic carbon concentration in remote areas

    NASA Astrophysics Data System (ADS)

    Avagyan, Armine; Runkle, Benjamin R. K.; Kutzbach, Lars

    2014-09-01

    Accurate quantification of dissolved organic carbon (DOC) in surface and soil pore waters is crucial for understanding changes in water resources under the influence of climate and land use changes. Sampling and laboratory analysis of DOC content at a sufficient temporal frequency are especially difficult to achieve for natural DOC sources like the extensive boreal and arctic mire landscapes due to their remoteness. Therefore, the goals of this paper are (1) to investigate the performance of a portable, high-resolution ultraviolet-visible light spectroscopic method for determining the DOC content of surface and soil pore water samples from a boreal mire complex and (2) to compare the spectroscopic method with other DOC measurement techniques, e.g., the wet heated persulfate oxidation method and a laboratory, expulsion-based spectrophotometric method and (3) to assess different multivariate models that relate absorbance measurements with DOC contents. The study indicates that high-resolution spectroscopic measurements provide a simple, robust and non-destructive method for measuring DOC content. These measurements are of short duration (<1 min) and the sample analysis is portable, rendering this method particularly advantageous for in situ investigations at remote field locations. The study also demonstrates that if absorbances at specific wavelengths are used as proxies for DOC concentration, it is recommended to create site-specific calibration models that include more than one wavelength to achieve the optimal accuracy of the proxy-based DOC quantification.

  19. High Resolution Surface Backscatter Measurements with the SeaWinds Scatterometer

    NASA Technical Reports Server (NTRS)

    Spencer, M. W.; Wu, C.; Long, D. G.

    1998-01-01

    A technique employed to extract higher resolution backscatter measurements from the SeaWinds pencil-beam scatterometer system is described. The unique methodology necessary to achieve very high radiometric accuracy for such measurements is discussed.

  20. Improved determination of seafloor absolute magnetization from uneven, near-seafloor magnetic measurements and high-resolution bathymetry

    NASA Astrophysics Data System (ADS)

    Szitkar, F.; Dyment, J.; Choi, Y.; Fouquet, Y.

    2012-12-01

    Vector magnetometers installed on deep-sea submersibles offer a unique opportunity to achieve high resolution magnetic investigations at the scale of hundred to thousand meters. Once corrected for the vehicle induced and remanent magnetization, the measurements mostly reflect variations of the topography and the submersible path - i.e. the distance between the sources and the observation points. The interesting parameter, however, is the seafloor magnetization that can be interpreted in terms of geological processes. Here we present methods to compute absolute magnetization of the seafloor by taking advantage of the uneven track of the submersible. In these methods, synthetic anomalies are computed for a unit magnetization assuming the geometry of the experiment, i.e. the source and the submersible path. The absolute magnetization is determined by a comparison between the observed anomalies and the synthetic ones along sliding windows. The coherency between the two signals gives an estimation of the quality of the determination, and the phase provides information on the magnetic polarity, and therefore the age of volcanic features. Such a method has been developed by Honsho et al. (JGR, 2009) using deep-sea submersible data only, i.e. magnetic anomaly, depth and altitude of the submersible. The synthetic anomalies are computed using 2D forward modeling, i.e. assuming the structures to be infinite in the direction perpendicular to the submersible path. The method has been applied with success to linear profiles crossing elongated structures such as mid-ocean ridges, but may fail for structures departing from the 2D assumption. The adaptation of improving multibeam systems to autonomous underwater vehicles (AUVs) has opened the way to the collection of very high resolution bathymetric data (around 2m between each measurement). This development has triggered a new strategy to explore the seafloor using manned submersibles: an AUV is operated during night time to

  1. New Measurements of Doubly Ionized Iron Group Spectra by High Resolution Fourier Transform and Grating Spectroscopy

    NASA Technical Reports Server (NTRS)

    Smillie, D. G.; Pickering, J. C.; Blackwell-Whitehead, R. J.; Smith, Peter L.; Nave, G.

    2006-01-01

    We report new measurements of doubly ionized iron group element spectra, important in the analysis of B-type (hot) stars whose spectra they dominate. These measurements include Co III and Cr III taken with the Imperial College VUV Fourier transform (FT) spectrometer and measurements of Co III taken with the normal incidence vacuum spectrograph at NIST, below 135 nm. We report new Fe III grating spectra measurements to complement our FT spectra. Work towards transition wavelengths, energy levels and branching ratios (which, combined with lifetimes, produce oscillator strengths) for these ions is underway.

  2. Determination of spectroscopic properties of atmospheric molecules from high resolution vacuum ultraviolet cross section and wavelength measurements

    NASA Technical Reports Server (NTRS)

    Parkinson, W. H.; Yoshino, K.; Freeman, D. E.

    1988-01-01

    Progress is given on work on: cross section measurements in the transmission window regions of the Schumann-Runge bands of oxygen; the determinations of predissociation linewidths; the theoretical calculation of band oscillator strengths of the Schumann-Runge absorption bands of O-16O-18; the determination of molecular spectroscopic constants; and the combined Herzberg continuum cross sections. The experimental investigations relevant to the cross section measurements, predissociation linewidths, and molecular spectroscopic constants are effected at high resolution with a 6.65 m scanning spectrometer which is, by virtue of its small instrumental width (FWHM = 0.0013 nm), suitable for cross section measurements of molecular bands with discrete rotational structure. Such measurements are needed for accurate calculations of the stratospheric production of atomic oxygen and heavy ozone formed following the photo-predissociation of O-16O-18 by solar radiation penetrating between the absorption lines of O-16(sub 2).

  3. Remote sounding of stratospheric temperatures using high resolution radiance measurements from the IRIS-D. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Gallery, W. O.

    1974-01-01

    Remote sounding of stratospheric temperatures up to 3.2 millibars is attempted using high resolution (unapodized) radiance measurements in the 15 micron CO2 band from the Infrared Interferometer Spectrometer on Nimbus 4. Inversions are performed using the Chahine relaxation technique. Radiance data and simultaneous in situ temperature profiles are obtained from the Rocket/Nimbus Sounder Comparison. Numerical tests with synthetic radiance data show that the uncertainty in the retrieved temperatures due to random instrument noise is about 1.1 K when averaged over layers about 10 km thick. However, comparison of the measured radiances with the radiances calculated from the in situ profiles show the calculated radiances to be systematically higher than the measured radiances. The evidence indicates that systematic errors exist in both the radiance and the in situ measurements.

  4. High resolution time interval meter

    DOEpatents

    Martin, A.D.

    1986-05-09

    Method and apparatus are provided for measuring the time interval between two events to a higher resolution than reliability available from conventional circuits and component. An internal clock pulse is provided at a frequency compatible with conventional component operating frequencies for reliable operation. Lumped constant delay circuits are provided for generating outputs at delay intervals corresponding to the desired high resolution. An initiation START pulse is input to generate first high resolution data. A termination STOP pulse is input to generate second high resolution data. Internal counters count at the low frequency internal clock pulse rate between the START and STOP pulses. The first and second high resolution data are logically combined to directly provide high resolution data to one counter and correct the count in the low resolution counter to obtain a high resolution time interval measurement.

  5. Flow velocimetry for weakly conducting electrolytes based on high resolution Lorentz force measurement.

    NASA Astrophysics Data System (ADS)

    Resagk, Christian; Ebert, Reschad; Vasilyan, Suren; Wiederhold, Andreas

    2013-11-01

    We demonstrate that a flow velocity measurement can be transformed into a non-invasive force measurement by metering the drag force acting on a system of magnets around a flow channel. This method is called Lorentz force velocimetry and has been developed in the last years in our institute. It is a feasible principle for materials with large conductivity like liquid metals. To evolve this method for weakly conducting fluids like salt water or molten glass the drag force measurement is the challenging bottleneck. Here forces of 10-8 and less of the weight force of the magnet system have to be resolved. In this paper different force measurement techniques get tested and compared. For the current setup the magnet system is attached to a state of the art electromagnetic force compensation balance. Different ways of getting the correct force signal out of the two measurement setups will be presented and discussed. For generalization of the measurement principle the Lorentz force is determined for different fluid profiles. In addition to that we have developed new systematic noise reduction methods to increase the resolution of the force measurement techniques by a factor of ten or larger which we will present here.

  6. Dynamic frequency-domain interferometer for absolute distance measurements with high resolution

    SciTech Connect

    Weng, Jidong; Liu, Shenggang; Ma, Heli; Tao, Tianjiong; Wang, Xiang; Liu, Cangli; Tan, Hua

    2014-11-15

    A unique dynamic frequency-domain interferometer for absolute distance measurement has been developed recently. This paper presents the working principle of the new interferometric system, which uses a photonic crystal fiber to transmit the wide-spectrum light beams and a high-speed streak camera or frame camera to record the interference stripes. Preliminary measurements of harmonic vibrations of a speaker, driven by a radio, and the changes in the tip clearance of a rotating gear wheel show that this new type of interferometer has the ability to perform absolute distance measurements both with high time- and distance-resolution.

  7. High-Resolution Measurements of Photoionization of Ions Using Synchrotron Radiation

    SciTech Connect

    Aguilar, A.; Covington, A.M.; Emmons, E.D.; Gharaibeh, M.F.; Phaneuf, R.A.; Alvarez, I.; Cisneros, C.; Hinojosa, G.; Dominguez, I.; Ackerman, G.; Bozek, J.D.; Canton, S.; Rude, B.; Sant'Anna, M.M.; Schlachter, A. S.; Folkmann, F.

    2003-08-26

    Measurement of absolute cross sections for photoionization of ions has become feasible by merging a well-collimated ion beam with a monochromatic beam of synchrotron radiation. An electron cyclotron resonance (ECR) ion source permits such measurements to be extended to multiply charged ions, and makes possible systematic studies along isoelectronic sequences. The evolution of atomic spectra along such sequences is commonly studied theoretically, but the predictive ability of the theoretical methods remains largely untested. Absolute cross-section measurements are presented for the first three ionic members of the isoelectronic sequence of nitrogen (O+, F2+ and Ne3+)

  8. Flow Velocimetry for Weakly Conducting Electrolytes Based on High Resolution Lorentzforce Measurement

    NASA Astrophysics Data System (ADS)

    Ebert, R.; Vasilyan, S.; Wiederhold, A.

    We demonstrate that a flow velocity measurement can be transformed into a non-invasive force measurement by metering the dragforce acting on a system of magnets that is arranged around a flow channel. This method is called Lorentzforce velocimetry and has been developed in the last years in our institute. It is a highly feasible principle for materials with large conductivity like liquid metals. To evolve this method for weakly conducting fluids like salt water or molten glass the dragforce measurement is the challenging bottleneck. Here forces of 10-8 and less of the weightforce of the magnet system have to be resolved in the rather noisy environment of the flow channel. In this paper different force measurement techniques get tested and compared. In the first setup the drag-force is acting on the magnets that are hanging as a pendulum with 0.5 m long wires on a mounting. Here the displacement in the range of a few μm can be detected with a laser interferometer and another optical positioning sensor. For the second setup the magnet system is attached to a state of the art electromagnetic force compensation balance. The balance is used in an unusual orientation: It is turned by 90 degrees to measure the horizontally acting Lorentzforce. Different ways of getting the correct force signal out of the two measurement setups will be presented and discussed. For generalization of the measurement principle the Lorentzforce is determined for different fluid profiles. In addition to that we have developed new systematic noise reduction methods to increase the resolution of both force measurement techniques by a factor of ten or larger which we will present here.

  9. Ice Fog and Light Snow Measurements Using a High-Resolution Camera System

    NASA Astrophysics Data System (ADS)

    Kuhn, Thomas; Gultepe, Ismail

    2016-07-01

    Ice fog, diamond dust, and light snow usually form over extremely cold weather conditions, and they affect both visibility and Earth's radiative energy budget. Prediction of these hydrometeors using models is difficult because of limited knowledge of the microphysical properties at the small size ranges due to measurement issues. These phenomena need to be better represented in forecast and climate models; therefore, in addition to remote sensing accurate measurements using ground-based instrumentation are required. An imaging instrument, aimed at measuring ice fog and light snow particles, has been built and is presented here. The ice crystal imaging (ICI) probe samples ice particles into a vertical, tapered inlet with an inlet flow rate of 11 L min-1. A laser beam across the vertical air flow containing the ice crystals allows for their detection by a photodetector collecting the scattered light. Detected particles are then imaged with high optical resolution. An illuminating LED flash and image capturing are triggered by the photodetector. In this work, ICI measurements collected during the fog remote sensing and modeling (FRAM) project, which took place during Winter of 2010-2011 in Yellowknife, NWT, Canada, are summarized and challenges related to measuring small ice particles are described. The majority of ice particles during the 2-month-long campaign had sizes between 300 and 800 μm. During ice fog events the size distribution measured had a lower mode diameter of 300 μm compared to the overall campaign average with mode at 500 μm.

  10. The Kinect as a low cost high resolution small scale LiDAR for water surface and shallow subsurface measurements

    NASA Astrophysics Data System (ADS)

    Mankoff, K. D.; Russo, T. A.

    2012-04-01

    The Microsoft Kinect, a video game input device designed for the Xbox system, can be used by earth scientists as a low cost high resolution LiDAR sensor. The device can see through at least 1 m of clear still water, or image the surface of opaque water. When observing through water the measurement is distorted by the refraction at the air/water interface. We present initial results of a calibration for sub-aqueous measurements, and describe a method for measuring sub-aqueous features and water height. When waves exist on the surface the signal is further convoluted and both the waves and subsurface are captured in the signal. We discuss signal deconvolution and techniques for capturing the relative and/or absolute values of surface waves and subsurface features.

  11. Determination of Spectroscopic Properties of Atmospheric Molecules from High Resolution Vacuum Ultraviolet Cross Section and Wavelength Measurements

    NASA Technical Reports Server (NTRS)

    Parkinson, W. H.; Yoshino, K.

    1999-01-01

    We have studied the spectroscopy and the cross sections of the simple molecules of atmospheric interest such as oxygen, nitric oxide, carbon dioxide, and water. We have made cross section measurements on an absolute base without the effects from the limited instrumental resolution. We have used the following different instruments- the grating spectrometer (6.65-m at CfA, 3-m at Photon Factory), VUV Fourier transform spectrometer at Imperial College, and then moved the same one to the Photon Factory. Selection of the instruments depend on the appearance of molecular bands, and their wavelength region. For example, the cross section measurements of Doppler limited bands can been done with the Fourier transform spectrometer at the very high resolution (0.025/ cm resolution). All of these spectroscopic measurements are needed for accurate calculations of the production of atomic oxygen penetration of solar radiation into the Earth's atmosphere, and photochemistry of minor molecules.

  12. Interpretation of data obtained with a high-resolution height-measuring corneal topographer

    NASA Astrophysics Data System (ADS)

    Jongsma, Franciscus H. M.; Stultiens, Bertho A. T.; Hendrikse, Fred

    1995-02-01

    Basically, other information becomes available when, instead of local slope, local height is measured. In contradistinction to the data obtained from Placido based systems, ambiguity can be avoided in the height data obtained from oblique projected grids on a diffusely reflecting surface, e.g., with an adapted set-up, discrimination between convex and concave surfaces is possible. We made a corneal topographer based on sodium-fluorescein installation in the precorneal tearfilm for obtaining a diffusely radiating surface. The local information available using a height measuring system, however, sometimes deviates from global information a.o. due to tearfilm breakup. This breakup may be controlled by applying artificial tear products. These products however, may influence the tearfilm thickness. With in vitro measurements we also obtained information about the thickness of a natural tearfilm that turned out to be at least several tens of micrometers s rather than 7 to 10 micrometers as is given in physiological handbooks. In this paper also a microslit-projection and observation method for direct tearlayer thickness measurements is described. The aim of this research is to investigate the maximum obtainable accuracy of measurements done in vivo and to optimize the sodium-fluorescein installation with respect to absorption of the excitation light and the fluorescent yield with minimum distortion of the natural corneal tearlayer.

  13. High resolution measurements of the Am241(n,2n) reaction cross section

    NASA Astrophysics Data System (ADS)

    Sage, C.; Semkova, V.; Bouland, O.; Dessagne, P.; Fernandez, A.; Gunsing, F.; Nästren, C.; Noguère, G.; Ottmar, H.; Plompen, A. J. M.; Romain, P.; Rudolf, G.; Somers, J.; Wastin, F.

    2010-06-01

    Measurements of the Am241(n,2n) reaction cross section have been performed at the Joint Research Centre (JRC) Geel in the frame of a collaboration between the European Commission (EC) JRC and French laboratories from CNRS and the Commissariat à L’Energie Atomique (CEA) Cadarache. Raw material coming from the Atalante facility of CEA Marcoule has been transformed by JRC Karlsruhe into suitable Am241O2 samples embedded in Al2O3 matrices specifically designed for these measurements. The irradiations were carried out at the 7-MV Van de Graaff accelerator. The Am241(n,2n) reaction cross section was determined relative to the Al27(n,α)Na24 standard cross section. The measurements were performed in four sessions, using quasi-mono-energetic neutrons with energies ranging from 8 to 21 MeV produced via the H2(d,n)He3 and the H3(d,n)He4 reactions. The induced activity was measured by standard γ-ray spectrometry using a high-purity germanium detector. Below 15 MeV, the present results are in agreement with data obtained earlier. Above 15 MeV, these measurements allowed the experimental investigation of the Am241(n,2n) reaction cross section for the first time. The present data are in good agreement with predictions obtained with the talys code that uses an optical and fission model developed at CEA.

  14. NMDB: real-time database for high resolution neutron monitor measurements

    NASA Astrophysics Data System (ADS)

    Steigies, Christian

    The worldwide network of standardized neutron monitors is, after 50 years, still the stateof-the-art instrumentation to measure variations of the primary cosmic rays in the energy range 500 MeV-60 GeV. These measurements are an ideal complement to space based cosmic ray measurements. Unlike data from satellite experiments, neutron monitor data has never been available in high time resolution from many neutron monitor stations in real-time. The data is often available only from the individual station's website, in varying formats, and not in real-time. To overcome this deficit, the European Commission is supporting the Neutron Monitor database (NMDB) since January 2008 as an e-Infrastructures project in the Seventh Framework Programme in the Capacities section. Neutron Monitor stations that do not yet have 1-minute resolution will be supported by software and the development of an affordable standard registration system to submit the measurements to the database via internet in realtime. This resolves the problem of different data formats and for the first time allows use of realtime cosmic ray measurements for space weather applications. Besides creating a database and developing applications that use this data, a part of the project is dedicated to create a public outreach website to inform about cosmic rays and possible effects on humans, technological systems, and the environment.

  15. High frequency, high resolution in situ measurement of Dissolved Organic Carbon

    NASA Astrophysics Data System (ADS)

    Hu, I. H.; Hemond, H.

    2013-12-01

    Dissolved Organic Carbon (DOC) is an important part of the carbon cycle in aquatic ecosystems and plays a fundamental role in numerous biogeochemical processes. Fast and accurate quantification of its concentration is necessary for several applications. For instance, determination of benthic fluxes of DOC via the eddy correlation (EC) method requires a sensor capable of precisely measuring DOC concentrations at a small point location, at a speed of several Hz. Such a sensor would enable the development of EC as a minimally invasive, in situ alternative to existing methods of DOC flux estimation, which currently include benthic chambers and sediment core incubations. A proof of concept instrument has been created capable of detecting naturally occurring levels of DOC at high speed via fluorescence measurements. Designed with the EC application in mind, the system utilizes optical fibers to transmit excitation and emission light, enabling in situ measurements at high spatial resolution. Emitted fluorescence light is passed through a tunable monochromator before reaching a photomultiplier tube; light level, and therefore solute concentration, is determined by photon counting. Preliminary results indicated that 100 Hz measurements of a 10 ppm humic acid solution were precise within 5%. The use of a tunable monochromator not only allows flexibility in detection wavelength, but also enables scans of the emission spectrum. The instrument thus is a dual-function device capable of both characterizing the chemistry of the water (e.g. characterizing the DOC present, or identifying additional compounds), and measuring fluorescence at selected wavelengths for EC and other applications.

  16. Deflection Measurements of a Thermally Simulated Nuclear Core Using a High-Resolution CCD-Camera

    NASA Technical Reports Server (NTRS)

    Stanojev, B. J.; Houts, M.

    2004-01-01

    Space fission systems under consideration for near-term missions all use compact. fast-spectrum reactor cores. Reactor dimensional change with increasing temperature, which affects neutron leakage. is the dominant source of reactivity feedback in these systems. Accurately measuring core dimensional changes during realistic non-nuclear testing is therefore necessary in predicting the system nuclear equivalent behavior. This paper discusses one key technique being evaluated for measuring such changes. The proposed technique is to use a Charged Couple Device (CCD) sensor to obtain deformation readings of electrically heated prototypic reactor core geometry. This paper introduces a technique by which a single high spatial resolution CCD camera is used to measure core deformation in Real-Time (RT). Initial system checkout results are presented along with a discussion on how additional cameras could be used to achieve a three- dimensional deformation profile of the core during test.

  17. Ice fog and light snow measurements using a high resolution camera system

    NASA Astrophysics Data System (ADS)

    Kuhn, Thomas; Gultepe, Ismail

    2016-04-01

    In this presentation, measurements collected by the ice crystal imaging (ICI) probe employed during FRAM (Fog Remote Sensing and Modeling) project for the Winter of 2010-2011 in Yellowknife, NWT, Canada are analysed to study small ice crystal impact on aviation operations. Ice fog, diamond dust, and light snow form during cold weather conditions and they affect aviation operations through visibility and deposition over the surfaces. In addition, these events influence the local heat budget through radiative cooling. Prediction of these hydrometeors using models is difficult because of limited knowledge of the microphysical properties at the small size ranges. These phenomena need to be better represented in forecast and climate models and this can only be done using accurate measurements from ground-based instrumentation. Imaging of ice particles' properties can complement other in-situ measurements being collected routinely. The newly developed ICI probe, aimed at measuring ice fog and light snow particles, is presented here. The ICI probe samples ice particles through a vertical inlet, where a laser beam and photodetector detect ice crystals contained in the flow. The detected particles are then imaged with high optical resolution between 10 to 1000 micron size range. An illuminating LED flash and image capturing for measurements are triggered by the photodetector. The results suggested that the majority of ice particles during the two-month long campaign were small with sizes between 300 μm and 800 μm. During ice fog events, the size distribution measured had a lower mode diameter of 300 μm compared to the overall campaign average with mode at 500 μm. In this presentation, challenges and issues related to small ice crystals are described and their importance for aviation operations and climate change are discussed.

  18. Real-time high-resolution measurement of collagen alignment in dynamically loaded soft tissue

    NASA Astrophysics Data System (ADS)

    York, Timothy; Kahan, Lindsey; Lake, Spencer P.; Gruev, Viktor

    2014-06-01

    A technique for creating maps of the direction and strength of fiber alignment in collagenous soft tissues is presented. The method uses a division of focal plane polarimeter to measure circularly polarized light transmitted through the tissue. The architecture of the sensor allows measurement of the retardance and fiber alignment at the full frame rate of the sensor without any moving optics. The technique compares favorably to the standard method of using a rotating polarizer. How the new technique enables real-time capture of the full angular spread of fiber alignment and retardance under various cyclic loading conditions is illustrated.

  19. High resolution kilometric range optical telemetry in air by radio frequency phase measurement

    NASA Astrophysics Data System (ADS)

    Guillory, Joffray; Šmíd, Radek; García-Márquez, Jorge; Truong, Daniel; Alexandre, Christophe; Wallerand, Jean-Pierre

    2016-07-01

    We have developed an optical Absolute Distance Meter (ADM) based on the measurement of the phase accumulated by a Radio Frequency wave during its propagation in the air by a laser beam. In this article, the ADM principle will be described and the main results will be presented. In particular, we will emphasize how the choice of an appropriate photodetector can significantly improve the telemeter performances by minimizing the amplitude to phase conversion. Our prototype, tested in the field, has proven its efficiency with a resolution better than 15 μm for a measurement time of 10 ms and distances up to 1.2 km.

  20. High resolution kilometric range optical telemetry in air by radio frequency phase measurement.

    PubMed

    Guillory, Joffray; Šmíd, Radek; García-Márquez, Jorge; Truong, Daniel; Alexandre, Christophe; Wallerand, Jean-Pierre

    2016-07-01

    We have developed an optical Absolute Distance Meter (ADM) based on the measurement of the phase accumulated by a Radio Frequency wave during its propagation in the air by a laser beam. In this article, the ADM principle will be described and the main results will be presented. In particular, we will emphasize how the choice of an appropriate photodetector can significantly improve the telemeter performances by minimizing the amplitude to phase conversion. Our prototype, tested in the field, has proven its efficiency with a resolution better than 15 μm for a measurement time of 10 ms and distances up to 1.2 km. PMID:27475593

  1. Small scale high resolution LiDAR measurements of a subglacial conduit

    NASA Astrophysics Data System (ADS)

    Mankoff, K. D.; Gulley, J.

    2012-04-01

    We present direct measurements of surface roughness in a sub-glacial conduit system underneath the Rieperbreen Glacier, Svalbard, Norway. Data was collected with a low-cost (129 USD) Microsoft Kinect video game device used as a LIDAR sensor. Surface roughness is a primary control on water flow in rivers, channels, and cave conduit systems and understanding the effects of surface roughness on water flow has been problematic due to lack of direct measurements of roughness in natural systems. We use the ice scallop dimensions to derive flow velocity and explore implications of the changing roughness parameters as the cave grows and shrinks.

  2. Prediction of sugarcane sucrose content with high resolution, hyperspectral leaf reflectance measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Experiments were conducted to determine if leaf reflectance measurements could be used to predict theoretically recoverable sugar (TRS) levels in sugarcane prior to harvest. Leaf and stalk samples were collected from multi-variety first-ratoon (FR) sugarcane maturity studies in 2005 at three sample ...

  3. Prediction of sugarcane sucrose content with high resolution, hyperspectral leaf reflectance measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Remote sensing for crop maturity parameters may offer sugarcane producers a method to develop harvest schedules that maximize sucrose production. Several tests were conducted to determine if leaf reflectance measurements could be used to predict theoretically recoverable sugar (TRS) levels (crop mat...

  4. A Novel, High Resolution, Non-Contact Channel Temperature Measurement Technique

    NASA Technical Reports Server (NTRS)

    Kim, Q.; Stark, B.; Kayali, S.

    1998-01-01

    An in-situ optical technique based on infrared emission spectroscopy has been developed for non-contact measurement of the temperature of a hot spot in the gate channel of a GaAs metal/semiconductor field effect transistor (MESFET).

  5. [High resolution measurement of concentrations and fluxes of heavy metals in pore waters by DGT].

    PubMed

    Fan, Ying-hong; Lin, Chun-ye; He, Meng-chang; Zhou, Yu-xiang; Yang, Zhi-feng

    2007-12-01

    Three sediment cores were collected from the Daliao River system in May 2006. The physico-chemical characteristics and heavy metal contents of sediment cores were analyzed. The vertical profiles of metals in pore water were measured by diffusive gradient in thin films (DGT) and centrifugal methods separately. The sequence of the concentrations of Cd, Co, Cr and Cu in sediment is Cr > Cu > Co > Cd. The concentrations measured by DGT were lower than that measured by centrifugal method. The average ratios of DGT measured concentrations (cDGT) to the concentrations measured by centrifugal method of Cd, Co, Cr and Cu were 0.389, 0.328, 0.863 and 0.403, respectively. This suggested that the release rates of these metals from solid phase to solution followed the sequence of Cr > Cu > Cd > Co. The fluxes of Cd, Co Cr and Cu were 1.12 x 10(-7) - 3.28 x 10(-7) nmol/(cm2 x s), 2.48 x 10(-7) - 10.40 x 10(-7) nmol/(cm2 x s), 8.80 x 10(-6) - 12.65 x 10(-6) nmol/(cm2 x s) and 6.14 x 10(-6) - 13.93 x 10(-6) nmol/(cm2 x s), respectively. The result showed that the release of Cd and Cu was mainly influenced by organic matter (OM), while Fe oxides, Mn oxides and OM were major factors controlling the transfer of Cr. The redox potential may be the major factor influencing the release of Co element. PMID:18290432

  6. Wavelength calibration of spectra measured by the Global Ozone Monitoring Experiment by use of a high-resolution reference spectrum.

    PubMed

    van Geffen, Jos H G M; van Oss, Roeland F

    2003-05-20

    Earthshine spectra measured by the nadir-viewing Global Ozone Monitoring Experiment (GOME) spectrometer aboard the second European Remote Sensing (ERS-2) Satellite in the range of 240-790 nm are widely used for the retrieval of concentrations and vertical profiles of atmospheric trace gases. For the near-real-time delivery of ozone columns and profiles at the Royal Netherlands Meterological Institute, a tailor-made wavelength calibration method was developed. The method use a high-resolution (0.01-nm) solar spectrum as the reference spectrum and applies both a shift and a squeeze to the wavelengths in selected windows to find the optimal wavelength grid per window. This method provides a calibration accuracy of 0.002 nm below and 0.001 nm above 290 nm. The new wavelength calibration method can be used on any wavelength window, for example, to improve the calibration of spectra from the GOME Data Processor. A software package, GomeCal, which performs this recalibration, along with an improved polarization and radiometric correction, has been made and has been released via the World Wide Web. The method can be used for any high-resolution (ir)radiance spectrometer, such as the satellite instruments SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric Cartography), Ozone Monitoring Instrument, and GOME-2. PMID:12777012

  7. Integrated reflectivity measurements of hydrogen phthalate crystals for high-resolution soft x-ray spectroscopy

    NASA Astrophysics Data System (ADS)

    Zastrau, U.; Förster, E.

    2014-09-01

    The integrated x-ray reflectivity of Potassium Hydrogen Phthalate (KAP) and Rubidium Hydrogen Phthalate (RAP) crystals is studied at a photon energy of (1740±14) eV using a double-crystal setup. The absolute measured reflectivities are in < 5% agreement with the values predicted by the dynamic diffraction theory for perfect crystals when absorption is included. Within 4% experimental error margins, specimen that were exposed to ambient conditions over many years show identical reflectivity as specimen that were cleaved just before the measurement. No differences are observed between cleaving off a 10 μm surface layer and splitting the entire crystal bulk of 2 mm thickness. We conclude that at 1.7 keV photon energy the penetration depth of ~ 1 μm is large compared to a potentially deteriorated surface layer of a few 10 nm.

  8. Characterization of fracture permeability with high-resolution vertical flow measurements during borehole pumping.

    USGS Publications Warehouse

    Paillet, Frederick L.; Hess, A.E.; Cheng, C.H.; Hardin, E.

    1987-01-01

    The distribution of fracture permeability in granitic rocks was investigated by measuring the distribution of vertical flow in boreholes during periods of steady pumping. Pumping tests were conducted at two sites chosen to provide examples of moderately fractured rocks near Mirror Lake, New Hampshire and intensely fractured rocks near Oracle, Arizona. A sensitive heat-pulse flowmeter was used for accurate measurements of vertical flow as low as 0.2 liter per minute. Results indicate zones of fracture permeability in crystalline rocks are composed of irregular conduits that cannot be approximated by planar fractures of uniform aperture, and that the orientation of permeability zones may be unrelated to the orientation of individual fractures within those zones.-Authors

  9. High-resolution, real-time simultaneous 3D surface geometry and temperature measurement.

    PubMed

    An, Yatong; Zhang, Song

    2016-06-27

    This paper presents a method to simultaneously measure three-dimensional (3D) surface geometry and temperature in real time. Specifically, we developed 1) a holistic approach to calibrate both a structured light system and a thermal camera under exactly the same world coordinate system even though these two sensors do not share the same wavelength; and 2) a computational framework to determine the sub-pixel corresponding temperature for each 3D point as well as discard those occluded points. Since the thermal 2D imaging and 3D visible imaging systems do not share the same spectrum of light, they can perform sensing simultaneously in real time: we developed a hardware system that can achieve real-time 3D geometry and temperature measurement at 26 Hz with 768 × 960 points per frame. PMID:27410608

  10. A high-resolution magnetic tweezer for single-molecule measurements

    PubMed Central

    Kim, Kipom; Saleh, Omar A.

    2009-01-01

    Magnetic tweezers (MT) are single-molecule manipulation instruments that utilize a magnetic field to apply force to a biomolecule-tethered magnetic bead while using optical bead tracking to measure the biomolecule’s extension. While relatively simple to set up, prior MT implementations have lacked the resolution necessary to observe sub-nanometer biomolecular configuration changes. Here, we demonstrate a reflection-interference technique for bead tracking, and show that it has much better resolution than traditional diffraction-based systems. We enhance the resolution by fabricating optical coatings on all reflecting surfaces that optimize the intensity and contrast of the interference image, and we implement feedback control of the focal position to remove drift. To test the system, we measure the length change of a DNA hairpin as it undergoes a folding/unfolding transition. PMID:19729511

  11. High resolution photofission measurements and intermediate structure in /sup 232/Th

    SciTech Connect

    Zhang, H.

    1986-01-01

    The photofission cross section of /sup 232/Th was measured in the energy range 5.8-12 MeV with an average photon energy resolution of 600 eV. The gamma rays, variable in energy, were obtained from narrow (p,..gamma..) resonances in various nuclei. Intermediate structure was observed at subbarrier excitation energies. The average spacing of photofission resonances provided the first relatively direct determination of the energy of the second minimum of the fission barrier, relative to the ground state. The measured fission probability and various properties of the intermediate structure were found to agree with calculated values based on a double bumped fission barrier. The features of this barrier, a rather high first hump and a deep secondary well, are quite different from the predictions of current theoretical barrier calculations.

  12. High-resolution micromechanical measurement in real time of forces exerted by living cells

    PubMed Central

    Swierczewski, Robert; Hedley, John; Redfern, Chris P. F.

    2016-01-01

    ABSTRACT The aim of this study was to compare uniaxial traction forces exerted by different cell types using a novel sensor design and to test the dependence of measured forces on cytoskeletal integrity. The sensor design detects forces generated between 2 contact points by cells spanning a gap. The magnitude of these forces varied according to cell type and were dependent on cytoskeletal integrity. The response time for drug-induced cytoskeletal disruption also varied between cell types: dermal fibroblasts exerted the greatest forces and had the slowest drug response times; EBV-transformed epithelial cells also had slow cytoskeletal depolymerisation times but exerted the lowest forces overall. Conversely, lung epithelial tumor cells exerted low forces but had the fastest depolymerisation drug response. These results provide proof of principle for a new design of force-measurement sensor based on optical interferometry, an approach that can be used to study cytoskeletal dynamics in real time. PMID:26645140

  13. A high resolution capacitive sensing system for the measurement of water content in crude oil.

    PubMed

    Zubair, Muhammad; Tang, Tong Boon

    2014-01-01

    This paper presents the design of a non-intrusive system to measure ultra-low water content in crude oil. The system is based on a capacitance to phase angle conversion method. Water content is measured with a capacitance sensor comprising two semi-cylindrical electrodes mounted on the outer side of a glass tube. The presence of water induces a capacitance change that in turn converts into a phase angle, with respect to a main oscillator. A differential sensing technique is adopted not only to ensure high immunity against temperature variation and background noise, but also to eliminate phase jitter and amplitude variation of the main oscillator that could destabilize the output. The complete capacitive sensing system was implemented in hardware and experiment results using crude oil samples demonstrated that a resolution of ± 50 ppm of water content in crude oil was achieved by the proposed design. PMID:24967606

  14. Measuring Curved Crystal Performance for a High Resolution, Imaging X-ray Spectrometer

    SciTech Connect

    Michael Haugh and Richard Stewart

    2010-06-07

    This paper describes the design, crystal selection, and crystal testing for a vertical Johann spectrometer operating in the 13 keV range to measure ion Doppler broadening in inertial confinement plasmas. The spectrometer is designed to use thin, curved, mica crystals to achieve a resolving power of E/ΔE>2000. A number of natural mica crystals were screened for flatness and X-ray diffraction width to find samples of sufficient perfection for use in the instrument. Procedures to select and mount high quality mica samples are discussed. A diode-type X-ray source coupled to a dual goniometer arrangement was used to measure the crystal reflectivity curve. A procedure was developed for evaluating the goniometer performance using a set of diffraction grade Si crystals. This goniometer system was invaluable for identifying the best original crystals for further use and developing the techniques to select satisfactory curved crystals for the spectrometer.

  15. Use of speckled speckles in high-resolution measurement of random bioflow

    NASA Astrophysics Data System (ADS)

    Ulyanov, Sergey S.

    1999-09-01

    The statement of the problem concerning the formation of speckled biospeckles with a small number of scatterers has been reviewed briefly in this paper. Formulas relating to diffraction of focused Gaussian beam from narrow random flow to bioliquid have been discussed. Flow has been considered as a set of moving random screens. Statistical properties of doubly scattered speckles have been investigated. The correlation function of intensity fluctuations of statistically inhomogeneous speckled speckles has been studied with regard to bioflow measurement. Dependencies of statistical characteristics of small-N cascade speckles on the number of scattering screens have been discussed. It has been shown that the value of Doppler bandwidth in the scattered light essentially depends on the spatial velocity distribution in the flow. Mechanism of formation of output signal of speckle-microscope for measurements of blood and lymph flow in narrow vessels has been also considered. Output characteristics of measuring system have been studied. Dependence of spectral moments of output signal of speckle-microscope on the velocity of bioflow and its scattering characteristics has been analyzed.

  16. Implementation of Ultrasonic Sensing for High Resolution Measurement of Binary Gas Mixture Fractions

    PubMed Central

    Bates, Richard; Battistin, Michele; Berry, Stephane; Bitadze, Alexander; Bonneau, Pierre; Bousson, Nicolas; Boyd, George; Bozza, Gennaro; Crespo-Lopez, Olivier; Riva, Enrico Da; Degeorge, Cyril; Deterre, Cecile; DiGirolamo, Beniamino; Doubek, Martin; Favre, Gilles; Godlewski, Jan; Hallewell, Gregory; Hasib, Ahmed; Katunin, Sergey; Langevin, Nicolas; Lombard, Didier; Mathieu, Michel; McMahon, Stephen; Nagai, Koichi; Pearson, Benjamin; Robinson, David; Rossi, Cecilia; Rozanov, Alexandre; Strauss, Michael; Vitek, Michal; Vacek, Vaclav; Zwalinski, Lukasz

    2014-01-01

    We describe an ultrasonic instrument for continuous real-time analysis of the fractional mixture of a binary gas system. The instrument is particularly well suited to measurement of leaks of a high molecular weight gas into a system that is nominally composed of a single gas. Sensitivity < 5 × 10−5 is demonstrated to leaks of octaflouropropane (C3F8) coolant into nitrogen during a long duration (18 month) continuous study. The sensitivity of the described measurement system is shown to depend on the difference in molecular masses of the two gases in the mixture. The impact of temperature and pressure variances on the accuracy of the measurement is analysed. Practical considerations for the implementation and deployment of long term, in situ ultrasonic leak detection systems are also described. Although development of the described systems was motivated by the requirements of an evaporative fluorocarbon cooling system, the instrument is applicable to the detection of leaks of many other gases and to processes requiring continuous knowledge of particular binary gas mixture fractions. PMID:24961217

  17. Implementation of ultrasonic sensing for high resolution measurement of binary gas mixture fractions.

    PubMed

    Bates, Richard; Battistin, Michele; Berry, Stephane; Bitadze, Alexander; Bonneau, Pierre; Bousson, Nicolas; Boyd, George; Bozza, Gennaro; Crespo-Lopez, Olivier; Da Riva, Enrico; Degeorge, Cyril; Deterre, Cecile; DiGirolamo, Beniamino; Doubek, Martin; Favre, Gilles; Godlewski, Jan; Hallewell, Gregory; Hasib, Ahmed; Katunin, Sergey; Langevin, Nicolas; Lombard, Didier; Mathieu, Michel; McMahon, Stephen; Nagai, Koichi; Pearson, Benjamin; Robinson, David; Rossi, Cecilia; Rozanov, Alexandre; Strauss, Michael; Vitek, Michal; Vacek, Vaclav; Zwalinski, Lukasz

    2014-01-01

    We describe an ultrasonic instrument for continuous real-time analysis of the fractional mixture of a binary gas system. The instrument is particularly well suited to measurement of leaks of a high molecular weight gas into a system that is nominally composed of a single gas. Sensitivity < 5 × 10(-5) is demonstrated to leaks of octaflouropropane (C3F8) coolant into nitrogen during a long duration (18 month) continuous study. The sensitivity of the described measurement system is shown to depend on the difference in molecular masses of the two gases in the mixture. The impact of temperature and pressure variances on the accuracy of the measurement is analysed. Practical considerations for the implementation and deployment of long term, in situ ultrasonic leak detection systems are also described. Although development of the described systems was motivated by the requirements of an evaporative fluorocarbon cooling system, the instrument is applicable to the detection of leaks of many other gases and to processes requiring continuous knowledge of particular binary gas mixture fractions. PMID:24961217

  18. High Resolution Muscle Measurements Provide Insights into Equinus Contractures in Patients with Cerebral Palsy

    PubMed Central

    Mathewson, Margie A.; Ward, Samuel R.; Chambers, Henry G.; Lieber, Richard L.

    2015-01-01

    Muscle contractures that occur after upper motor neuron lesion are often surgically released or lengthened. However, surgical manipulation of muscle length changes a muscle’s sarcomere length (Ls), which can affect force production. To predict effects of surgery, both macro- (fascicle length (Lf)) and micro- (Ls) level structural measurements are needed. Therefore, the purpose of this study was to quantify both Ls and Lf in patients with cerebral palsy (CP) as well as typically developing (TD) children. Soleus ultrasound images were obtained from children with CP and TD children. Lf was determined and, with the joint in the same position, CP biopsies were obtained, formalin fixed and Ls measured by laser diffraction. Since soleus Ls values were not measurable in TD children, TD Ls values were obtained using three independent methods. While average Lf did not differ between groups (CP=3.6±1.2 cm, TD=3.5±0.9 cm; p>0.6), Ls was dramatically longer in children with CP (4.07±0.45 μm vs. TD=2.17±0.24 μm; p<0.0001). While Lf values were similar between children with CP and TD children, this was due to highly stretched sarcomeres within the soleus muscle. Surgical manipulation of muscle-tendon unit length will thus alter muscle sarcomere length and change force generating capacity of the muscle. PMID:25242618

  19. A high-resolution measurement device for detecting the positioning accuracy of the optical fiber positioner

    NASA Astrophysics Data System (ADS)

    Gu, Yonggang; Xu, Jianlei; Jin, Yi; Zhai, Chao

    2012-09-01

    The optical fiber positioner with double revolving mechanism is driven by two stepping motors. One stepping motor drives center revolving mechanism and the other drives decentered slewing mechanism. Photogrammetry is currently used to detect the positioning accuracy of the optical fiber positioner, but it cannot achieve high precision because of the small size of the fiber’s diameter. So, a new measurement device, which mainly contained optical microscope, CCD camera and two-dimensional precision mobile platform, was established in this paper. One end of the optical fiber (the other end was lighted by integrating sphere light source) was imaged on the CCD sensor in a magnified way through the optical microscope, and the image was processed to build the position feedback mechanism in real time. Then the two-dimensional mobile platform was controlled by PID control method to track the optical fiber, and the fiber was always kept to locate in center of the CCD image in order to eliminate the aberrations of the optical microscope lens. Finally, the position changes of the moving fiber could be obtained by the coordinates of the two-dimensional precision mobile platform. The experimental results demonstrate that the resolution of this measurement device is 0.1μm and the accuracy of repeat positioning is 1.5μm. The measurement device could satisfy the testing requirement.

  20. High-resolution measurements of surface topography with airborne laser altimetry and the global positioning system

    NASA Technical Reports Server (NTRS)

    Garvin, James B.; Bufton, Jack L.; Cavanaugh, John F.; Krabill, William B.; Clem, Thomas D.; Frederick, Earl B.; Ward, John L.

    1991-01-01

    Recently, an airborne lidar system that measures laser pulse time-of-flight and the distortion of the pulse waveform upon reflection from earth surface terrain features was developed and is now operational. This instrument is combined with Global Positioning System (GPS) receivers and a two-axis gyroscope for accurate recovery of aircraft position and pointing attitude. The laser altimeter system is mounted on a high-altitude aircraft platform and operated in a repetitively-pulsed mode for measurements of surface elevation profiles at nadir. The laser transmitter makes use of recently developed short-pulse diode-pumped solid-state laser technology in Q-switched Nd:YAG operating at its fundamental wavelength of 1064 nm. A reflector telescope and silicon avalanche photodiode are the basis of the optical receiver. A high-speed time-interval unit and a separate high-bandwidth waveform digitizer under microcomputer control are used to process the backscattered pulses for measurements of terrain. Other aspects of the lidar system are briefly discussed.

  1. SU-E-I-40: New Method for Measurement of Task-Specific, High-Resolution Detector System Performance

    SciTech Connect

    Loughran, B; Singh, V; Jain, A; Bednarek, D; Rudin, S

    2014-06-01

    Purpose: Although generalized linear system analytic metrics such as GMTF and GDQE can evaluate performance of the whole imaging system including detector, scatter and focal-spot, a simplified task-specific measured metric may help to better compare detector systems. Methods: Low quantum-noise images of a neuro-vascular stent with a modified ANSI head phantom were obtained from the average of many exposures taken with the high-resolution Micro-Angiographic Fluoroscope (MAF) and with a Flat Panel Detector (FPD). The square of the Fourier Transform of each averaged image, equivalent to the measured product of the system GMTF and the object function in spatial-frequency space, was then divided by the normalized noise power spectra (NNPS) for each respective system to obtain a task-specific generalized signal-to-noise ratio. A generalized measured relative object detectability (GM-ROD) was obtained by taking the ratio of the integral of the resulting expressions for each detector system to give an overall metric that enables a realistic systems comparison for the given detection task. Results: The GM-ROD provides comparison of relative performance of detector systems from actual measurements of the object function as imaged by those detector systems. This metric includes noise correlations and spatial frequencies relevant to the specific object. Additionally, the integration bounds for the GM-ROD can be selected to emphasis the higher frequency band of each detector if high-resolution image details are to be evaluated. Examples of this new metric are discussed with a comparison of the MAF to the FPD for neuro-vascular interventional imaging. Conclusion: The GM-ROD is a new direct-measured task-specific metric that can provide clinically relevant comparison of the relative performance of imaging systems. Supported by NIH Grant: 2R01EB002873 and an equipment grant from Toshiba Medical Systems Corporation.

  2. High resolution deformation measurements at active volcanoes: a new remote sensing technology

    NASA Astrophysics Data System (ADS)

    Hort, M. K.; Scharff, L.; Gerst, A.; Meier, K.; Falk, S.; Peters, G.; Ripepe, M.

    2013-12-01

    It is known from observations at different volcanoes using ULP seismic observations that the volcanic edifice deforms slightly prior to an eruption. It can be expected that immediately prior to an eruption the largest deformation should occur in the vicinity of the vent. However, placing instruments at the vent is impossible as they will be destroyed during an eruption. Here we present new, high temporal resolution (up to 300Hz) deformation measurement that utilizes the phase information of a frequency modulated Doppler radar system. We decompose the Doppler signal into two parts, one part which allows us to measure speeds significantly above 0.5m/s (i.e. the movement of volcanic ash and clasts). The other part utilizes the slow phase changes of the signal reflected from non-moving objects, i.e. the volcanic edifice. This signal is used to measure very slow and longer term deformations, which are the main subject of this study. The method has been tested measuring the displacement of high rise buildings during strong winds. It can be shown that displacements down to 50 μm can be resolved without a problem. We apply this method to different data sets collected at Stromboli volcano, Italy, as well as Santiaguito volcano, Guatemala. At Stromboli we observed the NE crater once in 2008 and once in 2011. During both campaigns we observe on average a displacement between 1 and 5mm before different eruptions. This displacement can be interpreted as a widening of the conduit prior to an eruption. In a couple of cases even an oscillatory movement is observed with frequencies of about 0.5Hz. Finite element modeling of the rise of a pressurized slug indicates that deformations at the crater rim on the order of a 1mm or less are certainly reasonable. In the case of Santiaguito volcano prior to an eruption we observe a pre eruptive displacement 5-15mm and after the end of an eruption a displacement of up to 1m before the next eruption occurs. This can be interpreted as in

  3. Modular lidar systems for high-resolution 4-dimensional measurements of water vapor, temperature, and aerosols

    NASA Astrophysics Data System (ADS)

    Behrendt, Andreas; Wagner, Gerd; Petrova, Anna; Shiler, Max; Pal, Sandip; Schaberl, Thorsten; Wulfmeyer, Volker

    2005-01-01

    Three lidar systems are currently in development at University of Hohenheim. A water vapor lidar based on the differential absorption lidar (DIAL) technology working near 815 or 935 nm, a temperature and aerosol lidar employing the rotational Raman technique at 355 nm, and an aerosol lidar working with eye-safe laser radiation near 1.5 μm. The transmitters of these three systems are based on an injection-seeded, diode laser pumped Nd:YAG laser with an average power of 100 W at 1064 nm and a repetition rate of 250 Hz. This laser emits a nearly Gaussian-shaped beam which permits frequency-doubling and tripling with high efficiencies. The frequency-doubled 532-nm radiation is employed for pumping a Ti:Sapphire ring-resonator which will be used for DIAL water vapor measurements. In a second branch, a Cr4+:YAG crystal is pumped with the 1064-nm radiation to reach 1400 to 1500 nm for eye-safe monitoring of aerosol particles and clouds. The 532 and 1064 nm radiation are also used for backscatter lidar observations. Frequency tripling gives 355-nm radiation for measurements of temperature with the rotational Raman technique and particle extinction and particle backscattering coefficients in the UV. High transmitter power and effective use of the received signals will allow scanning operation of these three lidar systems. The lidar transmitters and detectors are designed as modules which can be combined for simultaneous measurements with one scanning telescope unit in a ground-based mobile container. Alternatively, they can be connected to different Nd:YAG pump lasers and to telescope units on separate platforms.

  4. High-Resolution ac Measurements of the Hall Effect in Organic Field-Effect Transistors

    NASA Astrophysics Data System (ADS)

    Chen, Y.; Yi, H. T.; Podzorov, V.

    2016-03-01

    We describe a high resolving power technique for Hall-effect measurements, efficient in determining Hall mobility and carrier density in organic field-effect transistors and other low-mobility systems. We utilize a small low-frequency ac magnetic field (Brms<0.25 T ) and a phase-sensitive (lock-in) detection of Hall voltage, with the necessary corrections for Faraday induction. This method significantly enhances the signal-to-noise ratio and eliminates the necessity of using high magnetic fields in Hall-effect studies. With the help of this method, we are able to obtain the Hall mobility and carrier density in organic transistors with a mobility as low as μ ˜0.3 cm2 V-1 s-1 by using a compact desktop apparatus and low magnetic fields. We find a good agreement between Hall-effect and electric-field-effect measurements, indicating that, contrary to the common belief, certain organic semiconductors with mobilities below 1 cm2 V-1 s-1 can still exhibit a fully developed, band-semiconductor-like Hall effect, with the Hall mobility and carrier density matching those obtained in longitudinal transistor measurements. This suggests that, even when μ <1 cm2 V-1 s-1 , charges in organic semiconductors can still behave as delocalized coherent carriers. This technique paves the way to ubiquitous Hall-effect studies in a wide range of low-mobility materials and devices, where it is typically very difficult to resolve the Hall effect even in very high dc magnetic fields.

  5. High-resolution methane emission estimates using surface measurements and the InTEM inversion system.

    NASA Astrophysics Data System (ADS)

    Connors, Sarah; Manning, Alistair; Robinson, Andrew; Riddick, Stuart; Forster, Grant; Oram, Dave; O'Doherty, Simon; Harris, Neil

    2015-04-01

    High quality GHG emission estimates will be required to successfully tackle climate change. There is a growing need for comparisons between emission estimates produced using bottom-up and top-down techniques at high spatial resolution. Here, a top-down inversion approach combining multi-year atmospheric measurements and an inversion model, InTEM, was used to estimate methane emissions for a region in the South East of the UK (~100 x 150 km). We present results covering a 2-year period (July 2012 - July 2014) in which atmospheric methane concentrations were recorded at 1 - 2 minute time-steps at four locations within the region of interest. Precise measurements were obtained using gas chromatography with flame ionisation detection (GC-FID) for all sites except one, which used a PICARRO Cavity Ring-Down Spectrometer (CRDS). These observations, along with the UK Met Office's Lagrangian particle dispersion model, NAME, were used within InTEM to produce the methane emission fields. We present results from both Bayesian and non-prior based inversion analysis at varying spatial resolutions, for annual, seasonal and monthly time frames. These results are compared with the UK National Atmospheric Emissions Inventory (NAEI) which is compiled using bottom-up methods and available at 1x1 km resolution. A thorough assessment of uncertainty is incorporated into this technique which is represented in the results. This project is part of the UK GAUGE campaign which aims to produce robust estimates of the UK GHG budget using new and existing measurement networks (e.g. the UK DECC GHG network) and modelling activities at a range of scales.

  6. Mid-Infrared OPO for High Resolution Measurements of Trace Gases in the Mars Atmosphere

    NASA Technical Reports Server (NTRS)

    Yu, Anthony W.; Numata,Kenji; Riris, haris; Abshire, James B.; Allan, Graham; Sun, Xiaoli; Krainak, Michael A.

    2008-01-01

    The Martian atmosphere is composed primarily (>95%) of CO2 and N2 gas, with CO, O2, CH4, and inert gases such as argon comprising most of the remainder. It is surprisingly dynamic with various processes driving changes in the distribution of CO2, dust, haze, clouds and water vapor on global scales in the meteorology of Mars atmosphere [I]. The trace gases and isotopic ratios in the atmosphere offer important but subtle clues as to the origins of the planet's atmosphere, hydrology, geology, and potential for biology. In the search for life on Mars, an important process is the ability of bacteria to metabolize inorganic substrates (H2, CO2 and rock) to derive energy and produce methane as a by-product of anaerobic metabolism. Trace gases have been measured in the Mars atmosphere from Earth, Mars orbit, and from the Mars surface. The concentration of water vapor and various carbon-based trace gases are observed in variable concentrations. Within the past decade multiple groups have reported detection of CH4, with concentrations in the 10's of ppb, using spectroscopic observations from Earth [2]. Passive spectrometers in the mid-infrared (MIR) are restricted to the sunlit side of the planet, generally in the mid latitudes, and have limited spectral and spatial resolution. To accurately map the global distribution and to locate areas of possibly higher concentrations of these gases such as plumes or vents requires an instrument with high sensitivity and fine spatial resolution that also has global coverage and can measure during both day and night. Our development goal is a new MIR lidar capable of measuring, on global scales, with sensitivity, resolution and precision needed to characterize the trace gases and isotopic ratios of the Martian atmosphere. An optical parametric oscillator operating in the MIR is well suited for this instrument. The sufficient wavelength tuning range of the OPO can extend the measurements to other organic molecules, CO2, atmospheric water

  7. Very high-resolution heat-capacity measurements near the lambda point of helium

    NASA Technical Reports Server (NTRS)

    Lipa, J. A.; Chui, T. C. P.

    1983-01-01

    New measurements of the heat capacity of a sample of helium 3-mm high are reported, which extend to within 5 x 10 to the -8th deg of the lambda transition at the vapor pressure. From an analysis of the results allowing for the effect of gravity, the values -0.0127 + or - 0.0026 (2 sigma) for the exponent alpha (= alpha-prime) and 1,058 + or - 0.004 for the leading singularity ratio A/A-prime are obtained. These values are in closer agreement with the theoretical predictions than those reported previously.

  8. High resolution photofission measurements in /sup 238/U and /sup 232/Th

    SciTech Connect

    Lancman, H.

    1984-01-01

    Photofission measurements have been continued at subbarrier energies. Strong intermediate resonances have been observed at an excitation energy of 6.14 MeV in /sup 232/Th. The photons were obtained from the E/sub p/ = 1020 keV resonance in /sup 34/S(P,..gamma..). Their average energy resolution was approx. 200 eV. Various properties of the observed intermediate structure were compared with theoretical predictions based on a double-humped and triple-humped barrier.

  9. High resolution measurements of dune movement in a scale model of the River Oder

    NASA Astrophysics Data System (ADS)

    Hüsener, Thorsten; Henning, Martin

    2010-05-01

    The paper presents the analysis of three dimensional river bed topographies of high spatial and temporal resolution, obtained from scale model experiments with movable bed. The use of a stereo photogrammetric system allowed for measuring the submerged river bed during the laboratory experiments. The system is based on three synchronized cameras and a bar code system for orientation and can be used in both dry and wet conditions. For bed surface elevation measurements, a grid is projected onto the channel bed, defining the bed surface via slide projection. When applied to subaqueous problems, the system provides reliable data and insight in the distribution and migration of bed forms and the impact of steady and unsteady discharges on bed topography. The presented data has been obtained from a hydraulic scale model with moveable bed, concerning an 8km long reach of the River Oder at the German-Polish border. The model has been set up in order to investigate the influence of river training measures on accessible water depths and on the development of river bed forms. To determine the movement of the dunes, a 3 x 3 m² area of the model, representing 90,000 m² in field scale, has been recorded over a time of 11 h, providing 4000 topographic data sets of about 10,000 data points each. To simulate nature like transport conditions, the natural bedload material was substituted by synthetic granules (polystyrene) with lesser density and coarser diameter. Due to the small density of polystyrene the dune migration was considerably faster than it would have been for the use of sand as bed load material. In theory, flow is often assumed to be steady and uniform. However, during sediment transport, bed topography changes continuously. The presented analysis of the data shows the wide spatial and temporal variety of occurring dunes and the correlation between dune dimen-sions and dune migration speed. Possible future analysis of the three-dimensional data will be discussed and

  10. A High Resolution Radar Altimeter to Measure the Topography of Ice Sheets

    NASA Technical Reports Server (NTRS)

    Pawul, Rudolf A.

    1997-01-01

    This thesis is a reference for the Advanced Application Flight Experiment (AAFE) altimeter. The transmitter and receiver subsections are described and measurements of their current state is provided. During the 1994 NASA Greenland Experiment, the altimeter experienced several hardware malfunctions. The process of returning the radar to its fully operational state is presented in detail and necessary design modifications are explained. An updated radar user's manual is included along with various circuit designs which need to be implemented. The thesis is intended to provide an incoming graduate student with a solid foundation of the fundamentals of AAFE altimeter operation.