One-Micron Beams for Macromolecular Crystallography at GM/CA-CAT

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yoder, D. W.; Sanishvili, R.; Xu, S.

2010-06-23

GM/CA-CAT has developed a 1-{mu}m beam for challenging micro-diffraction experiments with macromolecular crystals (e.g. small crystals) and for radiation damage studies. Reflective (Kirkpatrick-Baez mirrors) and diffractive (Fresnel zone plates) optics have been used to focus the beam. Both cases are constrained by the need to maintain a small beam convergence. Using two different zone plates, 1.0x1.0 and 0.8x0.9 {mu}m{sup 2} (VxH,FWHM) beams were created at 15.2 keV and 18.5 keV, respectively. Additionally, by introducing a vertical focusing mirror upstream of the zone plate, a line focus at 15.2 keV was created (28x1.4 {mu}m{sup 2} VxH,FWHM) with the line oriented perpendicularmore » to the X-ray polarization and the crystal rotation axis. Crystal-mounting stages with nanometer resolution have been assembled to profile these beams and to perform diffraction experiments.« less

A novel method to fabricate silicon tubular gratings with broadband antireflection and super-hydrophobicity.

PubMed

Gao, Yang; Shi, Tielin; Tan, Xianhua; Liao, Guanglan

2014-06-01

We have developed a novel method to fabricate micro/nano structure based on the coherent diffraction lithography, and acquired periodic silicon tubular gratings with deep nano-scale tapered profiles at the top part. The optical properties of these tubular gratings were similar to an effective gradient-index antireflective surface, resulting in a broadband antireflective combining super-hydrophobic behavior. The mechanism of the method was simulated by rigorous coupled wave analysis algorithms. Then coherent diffraction lithography by use of suitable mask, in which periodic micro-scale circular opaque patters were distributed, was realized on the traditional aligner. Due to coherent diffraction, we obtained enough light intensity for photoresist exposure under the center of the opaque area in the mask together with transparent areas. The tapered line profiles and hollow photoresist gratings over large areas could be fabricated on the silicon wafer after development. The dry etching process was carried out, and high aspect ratio silicon tubular gratings with deep tapered profiles at the top were fabricated. The optical property and wettability of the structure were verified, proving that the proposed method and obtained micro/nano structure provide application potential in the future.

Structure, Elastic Constants and XRD Spectra of Extended Solids under High Pressure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Batyrev, I. G.; Coleman, S. P.; Ciezak-Jenkins, J. A.

We present results of evolutionary simulations based on density functional calculations of a potentially new type of energetic materials called extended solids: P-N and N-H. High-density structures with covalent bonds generated using variable and fixed concentration methods were analysed in terms of thermo-dynamical stability and agreement with experimental X-ray diffraction (XRD) spectra. X-ray diffraction spectra were calculated using a virtual diffraction algorithm that computes kinematic diffraction intensity in three-dimensional reciprocal space before being reduced to a two-theta line profile. Calculated XRD patterns were used to search for the structure of extended solids present at experimental pressures by optimizing data accordingmore » to experimental XRD peak position, peak intensity and theoretically calculated enthalpy. Elastic constants has been calculated for thermodynamically stable structures of P-N system.« less

Probing multiscale transport and inhomogeneity in a lithium-ion cells using in-situ neutron methods

DOE PAGES

Zhou, Hui; An, Ke; Allu, Srikanth; ...

2016-01-01

Here, we demonstrate for the first time the lithiation process in graphitic anodes using insitu neutron radiography in a pouch cell format. The neutron absorption contrast shows a direct correlation between degree of lithiation and the discharge voltage plateau. Furthermore, we provide a semi-quantitative comparison between the observed spatial variations of neutron attenuation line profile across the graphite electrode and the calculated lithium concentration profiles computed under similar electrochemical discharge conditions. In conjunction, in situ neutron diffraction of a similar pouch cell under identical test protocol was carried to obtain information about the local phase changes upon lithiation. Combined in-situmore » radiography and diffraction opens up a powerful nondestructive method to understand the multi-scale nature of lithium transport and degradation in practical lithium-ion cells.« less

Analyse de l'état mécanique et microstructural de films minces supraconducteurs YBa_2 Cu_3O_7 par diffraction des rayons X

NASA Astrophysics Data System (ADS)

Auzary, S.; Badawi, K. F.; Bimbault, L.; Rabier, J.; Gaboriaud, R. J.; Goudeau, Ph.

1997-01-01

Mechanical and microstructural analysis in a 100nm thin film is presented in this study. Using X-ray diffraction with a tensorial approach, we have determined stresses, strains, stress-free lattice parameters, microdistorsions and diffracting coherent domains size. Stress-free lattice parameters are higher than the bulk values. A high value of stresses is explained as a combination of coherent stresses, thermal stresses and intrinsic ones. Diffraction peaks line profiles analysis suggests grain boundaries presence as well as high lattice elastic microdistorsions. Cette étude présente une analyse de l'état mécanique et microstructurale dans un film mince de 100nm d'épaisseur d'YBCO déposé sur un substrat de MgO. En utilisant la diffraction des rayons X couplée à une approche tensorielle, nous avons déterminé les déformations, les contraintes, les paramètres libres de contraintes, les microdistorsions élastiques ainsi que la taille des domaines cohérents de diffraction. Les paramètres libres de contrainte sont supérieurs à ceux du massif. Une valeur élevée des contraintes est expliquée à partir des contraintes de cohérence, des contraintes thermiques et intrinsèques. L'analyse des profils des pics de diffraction suggère la présence de sous-joints et de distorsions élastiques élevées au niveau des mailles cristallographiques.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Xiuguo; Ma, Zhichao; Xu, Zhimou

Mueller matrix ellipsometry (MME) is applied to detect foot-like asymmetry encountered in nanoimprint lithography (NIL) processes. We present both theoretical and experimental results which show that MME has good sensitivity to both the magnitude and direction of asymmetric profiles. The physics behind the use of MME for asymmetry detection is the breaking of electromagnetic reciprocity theorem for the zeroth-order diffraction of asymmetric gratings. We demonstrate that accurate characterization of asymmetric nanoimprinted gratings can be achieved by performing MME measurements in a conical mounting with the plane of incidence parallel to grating lines and meanwhile incorporating depolarization effects into the opticalmore » model. The comparison of MME-extracted asymmetric profile with the measurement by cross-sectional scanning electron microscopy also reveals the strong potential of this technique for in-line monitoring NIL processes, where symmetric structures are desired.« less

Electromagnetic ray tracing model for line structures.

PubMed

Tan, C B; Khoh, A; Yeo, S H

2008-03-17

In this paper, a model for electromagnetic scattering of line structures is established based on high frequency approximation approach - ray tracing. This electromagnetic ray tracing (ERT) model gives the advantage of identifying each physical field that contributes to the total solution of the scattering phenomenon. Besides the geometrical optics field, different diffracted fields associated with the line structures are also discussed and formulated. A step by step addition of each electromagnetic field is given to elucidate the causes of a disturbance in the amplitude profile. The accuracy of the ERT model is also discussed by comparing with the reference finite difference time domain (FDTD) solution, which shows a promising result for a single polysilicon line structure with width of as narrow as 0.4 wavelength.

PVA/NaCl/MgO nanocomposites-microstructural analysis by whole pattern fitting method

NASA Astrophysics Data System (ADS)

Prashanth, K. S.; Mahesh, S. S.; Prakash, M. B. Nanda; Somashekar, R.; Nagabhushana, B. M.

2018-04-01

The nanofillers in the macromolecular matrix have displayed noteworthy changes in the structure and reactivity of the polymer nanocomposites. Novel functional materials usually consist of defects and are largely disordered. The intriguing properties of these materials are often attributed to defects. X-ray line profiles from powder diffraction reveal the quantitative information about size distribution and shape of diffracting domains which governs the contribution from small conventional X-ray diffraction (XRD) techniques to enumerate the microstructural information. In this study the MgO nanoparticles were prepared by solution combustion method and PVA/NaCl/MgO nanocomposite films were synthesized by the solvent cast method. Microstructural parameters viz crystal defects like stacking faults and twin faults, compositional inhomogeneity, crystallite size and lattice strain (g in %), were extracted using whole pattern fitting method.

Catastrophe Optics Method to Determine the Micro-Nano Size Profiles at TPL of Liquid Films on a Solid Surface

NASA Technical Reports Server (NTRS)

Chao, David F.; McQuillen, J. B.; Sankovic, J. M.; Zhang, Nengli

2009-01-01

As discovered by recent studies, what directly affects the wetting and spreading is curvature in micro-region rather than the macroscopic contact angle. Measuring the profile of the micro-region becomes an important research topic. Recently, catastrophe optics has been applied to this kind of measurements. Optical catastrophe occurring in far field of waves of liquid-refracted laser beam implies a wealth of information about the liquid spreading not only for liquid drops but also for films. When a parallel laser beam passes through a liquid film on a slide glass at three-phase-line (TPL), very interesting optical image patterns occur on a screen far from the film. An analysis based on catastrophe optics discloses and interprets the formation of these optical image patterns. The analysis reveals that the caustic line manifested as the bright-thick line on the screen implies the lowest hierarchy of optical catastrophes, called fold caustic. This optical catastrophe is produced by the inflexion line on liquid surface at the liquid foot, which is formed not only in the spreading of drops but also in spreading of films. The generalized catastrophe optics method enables to identify the edge profiles and determine the edge foot height of liquid films. Keywords: Crossover region, Inflexion line, liquid edge foot, Catastrophe optics, Caustic and diffraction

Determination of line profiles on nano-structured surfaces using EUV and x-ray scattering

NASA Astrophysics Data System (ADS)

Soltwisch, Victor; Wernecke, Jan; Haase, Anton; Probst, Jürgen; Schoengen, Max; Krumrey, Michael; Scholze, Frank; Pomplun, Jan; Burger, Sven

2014-09-01

Non-imaging techniques like X-ray scattering are supposed to play an important role in the further development of CD metrology for the semiconductor industry. Grazing Incidence Small Angle X-ray Scattering (GISAXS) provides directly assessable information on structure roughness and long-range periodic perturbations. The disadvantage of the method is the large footprint of the X-ray beam on the sample due to the extremely shallow angle of incidence. This can be overcome by using wavelengths in the extreme ultraviolet (EUV) spectral range, EUV small angle scattering (EUVSAS), which allows for much steeper angles of incidence but preserves the range of momentum transfer that can be observed. Generally, the potentially higher momentum transfer at shorter wavelengths is counterbalanced by decreasing diffraction efficiency. This results in a practical limit of about 10 nm pitch for which it is possible to observe at least the +/- 1st diffraction orders with reasonable efficiency. At the Physikalisch-Technische Bundesanstalt (PTB), the available photon energy range extends from 50 eV up to 10 keV at two adjacent beamlines. PTB commissioned a new versatile Ellipso-Scatterometer which is capable of measuring 6" square substrates in a clean, hydrocarbon-free environment with full flexibility regarding the direction of the incident light polarization. The reconstruction of line profiles using a geometrical model with six free parameters, based on a finite element method (FEM) Maxwell solver and a particle swarm based least-squares optimization yielded consistent results for EUV-SAS and GISAXS. In this contribution we present scatterometry data for line gratings and consistent reconstruction results of the line geometry for EUV-SAS and GISAXS.

Numerical and neutron diffraction measurement of residual stress distribution in dissimilar weld

DOE PAGES

Eisazadeh, Hamid; Bunn, Jeffrey R.; Aidun, Daryush K.

2017-01-01

In this study, a model considering an asymmetric power heat distribution, temperature-dependent material properties, strain hardening and phase transformation was developed to predict temperature field and residual stress distribution in GTA dissimilar weld between austenitic stainless steel (304) and low carbon steel (1018). The effect of martensite formation on longitudinal and transverse residual stress distributions were investigated using both FE model and neutron diffraction measurement. The results indicate that martensitic phase has a significant influence on both residual stress components, i.e., transverse and longitudinal, and it not only can change the distribution shape of residual stress near the weld centermore » line but, also, can alter the peak value of the residual stresses. The calculated temperature and weld zone profile were in agreement with the experimental results. Favorable general agreement was also found between the calculated residual stress distribution and residual stress measurements by the neutron diffraction method.« less

Numerical and neutron diffraction measurement of residual stress distribution in dissimilar weld

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eisazadeh, Hamid; Bunn, Jeffrey R.; Aidun, Daryush K.

In this study, a model considering an asymmetric power heat distribution, temperature-dependent material properties, strain hardening and phase transformation was developed to predict temperature field and residual stress distribution in GTA dissimilar weld between austenitic stainless steel (304) and low carbon steel (1018). The effect of martensite formation on longitudinal and transverse residual stress distributions were investigated using both FE model and neutron diffraction measurement. The results indicate that martensitic phase has a significant influence on both residual stress components, i.e., transverse and longitudinal, and it not only can change the distribution shape of residual stress near the weld centermore » line but, also, can alter the peak value of the residual stresses. The calculated temperature and weld zone profile were in agreement with the experimental results. Favorable general agreement was also found between the calculated residual stress distribution and residual stress measurements by the neutron diffraction method.« less

Proton irradiation studies on Al and Al5083 alloy

NASA Astrophysics Data System (ADS)

Bhattacharyya, P.; Gayathri, N.; Bhattacharya, M.; Gupta, A. Dutta; Sarkar, Apu; Dhar, S.; Mitra, M. K.; Mukherjee, P.

2017-10-01

The change in the microstructural parameters and microhardness values in 6.5 MeV proton irradiated pure Al and Al5083 alloy samples have been evaluated using different model based techniques of X-ray diffraction Line Profile Analysis (XRD) and microindendation techniques. The detailed line profile analysis of the XRD data showed that the domain size increases and saturates with irradiation dose both in the case of Al and Al5083 alloy. The corresponding microstrain values did not show any change with irradiation dose in the case of the pure Al but showed an increase at higher irradiation doses in the case of Al5083 alloy. The microindendation results showed that unirradiated Al5083 alloy has higher hardness value compared to that of unirradiated pure Al. The hardness increased marginally with irradiation dose in the case of Al5083, whereas for pure Al, there was no significant change with dose.

Atomic Physics of Shocked Plasma in Winds of Massive Stars

NASA Technical Reports Server (NTRS)

Leutenegger, Maurice A.; Cohen, David H.; Owocki, Stanley P.

2012-01-01

High resolution diffraction grating spectra of X-ray emission from massive stars obtained with Chandra and XMM-Newton have revolutionized our understanding of their powerful, radiation-driven winds. Emission line shapes and line ratios provide diagnostics on a number of key wind parameters. Modeling of resolved emission line velocity profiles allows us to derive independent constraints on stellar mass-loss rates, leading to downward revisions of a factor of a few from previous measurements. Line ratios in He-like ions strongly constrain the spatial distribution of Xray emitting plasma, confirming the expectations of radiation hydrodynamic simulations that X-ray emission begins moderately close to the stellar surface and extends throughout the wind. Some outstanding questions remain, including the possibility of large optical depths in resonance lines, which is hinted at by differences in line shapes of resonance and intercombination lines from the same ion. Resonance scattering leads to nontrivial radiative transfer effects, and modeling it allows us to place constraints on shock size, density, and velocity structure

Adhesive micro-line periodicity determines guidance of axonal outgrowth†

PubMed Central

Huang, Yu; Fothergill, Thomas; Lumbard, Derek C.; Dent, Erik W.; Williams, Justin C.

2014-01-01

Adhesive micro-lines of various sub-cellular geometries were created using a non-traditional micro stamping technique. This technique employed the use of commercially available diffraction gratings as the molds for the micro stamps, a method which is quick and inexpensive, and which could easily be adopted as a patterning tool in a variety of research efforts. The atypical saw-tooth profile of the micro stamps enabled a unique degree of control and flexibility over patterned line and gap widths. Cortical neurons cultured on patterned poly-lysine micro-lines on PDMS exhibit a startling transition in axonal guidance: From the expected parallel guidance to an unexpected perpendicular guidance that becomes dominant as patterned lines and gaps become sufficiently narrow. This transition is most obvious when the lines are narrow relative to gaps, while the periodicity of the pattern is reduced. Axons growing perpendicular to micro-lines exhibited ‘vinculated’ growth, a unique morphological phenotype consisting of periodic orthogonal extensions along the axon. PMID:23250489

Diffraction efficiency of plasmonic gratings fabricated by electron beam lithography using a silver halide film

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sudheer,, E-mail: sudheer@rrcat.gov.in, E-mail: sudheer.rrcat@gmail.com; Tiwari, P.; Srivastava, Himanshu

2016-07-28

The silver nanoparticle surface relief gratings of ∼10 μm period are fabricated using electron beam lithography on the silver halide film substrate. Morphological characterization of the gratings shows that the period, the shape, and the relief depth in the gratings are mainly dependent on the number of lines per frame, the spot size, and the accelerating voltage of electron beam raster in the SEM. Optical absorption of the silver nanoparticle gratings provides a broad localized surface plasmon resonance peak in the visible region, whereas the intensity of the peaks depends on the number density of silver nanoparticles in the gratings. Themore » maximum efficiency of ∼7.2% for first order diffraction is observed for the grating fabricated at 15 keV. The efficiency is peaking at 560 nm with ∼380 nm bandwidth. The measured profiles of the diffraction efficiency for the gratings are found in close agreement with the Raman-Nath diffraction theory. This technique provides a simple and efficient method for the fabrication of plasmonic nanoparticle grating structures with high diffraction efficiency having broad wavelength tuning.« less

Solar Confocal interferometers for Sub-Picometer-Resolution Spectral Filters

NASA Technical Reports Server (NTRS)

Gary, G. Allen; Pietraszewski, Chris; West, Edward A.; Dines. Terence C.

2007-01-01

The confocal Fabry-Perot interferometer allows sub-picometer spectral resolution of Fraunhofer line profiles. Such high spectral resolution is needed to keep pace with the higher spatial resolution of the new set of large-aperture solar telescopes. The line-of-sight spatial resolution derived for line profile inversions would then track the improvements of the transverse spatial scale provided by the larger apertures. In particular, profile inversion allows improved velocity and magnetic field gradients to be determined independent of multiple line analysis using different energy levels and ions. The confocal interferometer's unique properties allow a simultaneous increase in both etendue and spectral power. The higher throughput for the interferometer provides significant decrease in the aperture, which is important in spaceflight considerations. We have constructed and tested two confocal interferometers. A slow-response thermal-controlled interferometer provides a stable system for laboratory investigation, while a piezoelectric interferometer provides a rapid response for solar observations. In this paper we provide design parameters, show construction details, and report on the laboratory test for these interferometers. The field of view versus aperture for confocal interferometers is compared with other types of spectral imaging filters. We propose a multiple etalon system for observing with these units using existing planar interferometers as pre-filters. The radiometry for these tests established that high spectral resolution profiles can be obtained with imaging confocal interferometers. These sub-picometer spectral data of the photosphere in both the visible and near-infrared can provide important height variation information. However, at the diffraction-limited spatial resolution of the telescope, the spectral data is photon starved due to the decreased spectral passband.

Williamson-Hall analysis and optical properties of small sized ZnO nanocrystals

NASA Astrophysics Data System (ADS)

Kalita, Amarjyoti; Kalita, Manos P. C.

2017-08-01

We apply Williamson-Hall (WH) method of X-ray diffraction (XRD) line profile analysis for lattice strain estimation of small sized ZnO nanocrystals (crystallite size≈4 nm). The ZnO nanocrystals are synthesized by room temperature chemical co-precipitation followed by heating at 40 °C. Zinc acetate, sodium hydroxide and 2-mercaptoethanol (ME) are used for the synthesis of the nanocrystals. {100}, {002}, {101} and {200}, {112}, {201} line profiles in the XRD pattern are significantly merged, therefore determination of the full width at half maximum values and peak positions of the line profiles required for WH analysis has been carried out by executing Rietveld refinement of the XRD pattern. Lattice strain of the 4 nm sized ZnO nanocrystals is found to be 5.8×10-3 which is significantly higher as compared to the literature reported values for larger ones (crystallite size≈17-47 nm). Role of ME as capping agent is confirmed by Fourier transform infrared spectroscopy. The band gap of the nanocrystals is determined from the UV-Visible absorption spectrum and is found to be 3.68 eV. The photoluminescence spectrum exhibits emissions in the visible (408 nm-violet, 467 nm-blue and 538 nm-green) regions showing presence of zinc interstitial and oxygen vacancy in the ZnO nanocrystals.

Ultra-high density diffraction grating

DOEpatents

Padmore, Howard A.; Voronov, Dmytro L.; Cambie, Rossana; Yashchuk, Valeriy V.; Gullikson, Eric M.

2012-12-11

A diffraction grating structure having ultra-high density of grooves comprises an echellette substrate having periodically repeating recessed features, and a multi-layer stack of materials disposed on the echellette substrate. The surface of the diffraction grating is planarized, such that layers of the multi-layer stack form a plurality of lines disposed on the planarized surface of the structure in a periodical fashion, wherein lines having a first property alternate with lines having a dissimilar property on the surface of the substrate. For example, in one embodiment, lines comprising high-Z and low-Z materials alternate on the planarized surface providing a structure that is suitable as a diffraction grating for EUV and soft X-rays. In some embodiments, line density of between about 10,000 lines/mm to about 100,000 lines/mm is provided.

Determination of the gaseous hydrogen ductile-brittle transition in copper-nickel alloys

NASA Technical Reports Server (NTRS)

Parr, R. A.; Johnston, M. H.; Davis, J. H.; Oh, T. K.

1985-01-01

A series of copper-nickel alloys were fabricated, notched tensile specimens machined for each alloy, and the specimens tested in 34.5 MPa hydrogen and in air. A notched tensile ratio was determined for each alloy and the hydrogen environment embrittlement (HEE) determined for the alloys of 47.7 weight percent nickel to 73.5 weight percent nickel. Stacking fault probability and stacking fault energies were determined for each alloy using the x ray diffraction line shift and line profiles technique. Hydrogen environment embrittlement was determined to be influenced by stacking fault energies; however, the correlation is believed to be indirect and only partially responsible for the HEE behavior of these alloys.

X-ray investigation of cross-breed silk in cocoon, yarn and fabric forms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Radhalakshmi, Y. C.; Kariappa,; Siddaraju, G. N.

2012-06-05

Recently Central Sericulture Research and Training Institute, Mysore developed many improved cross breeds and bivoltine hybrids. Newly developed cross breeds recorded fibre characteristics which are significantly superior over existing control hybrids. This aspect has been investigated using X-ray diffraction technique. We have employed line profile analysis to compute microstructural parameters. These parameters are compared with physical parameters of newly developed cross breed silk fibers for a better understanding of structure-property relation in these samples.

Graphene oxide as a nanocarrier for controlled release and targeted delivery of an anticancer active agent, chlorogenic acid.

PubMed

Barahuie, Farahnaz; Saifullah, Bullo; Dorniani, Dena; Fakurazi, Sharida; Karthivashan, Govindarajan; Hussein, Mohd Zobir; Elfghi, Fawzi M

2017-05-01

We have synthesized graphene oxide using improved Hummer's method in order to explore the potential use of the resulting graphene oxide as a nanocarrier for an active anticancer agent, chlorogenic acid (CA). The synthesized graphene oxide and chlorogenic acid-graphene oxide nanocomposite (CAGO) were characterized using Fourier transform infrared (FTIR) spectroscopy, thermogravimetry and differential thermogravimetry analysis, Raman spectroscopy, powder X-ray diffraction (PXRD), UV-vis spectroscopy and high resolution transmission electron microscopy (HRTEM) techniques. The successful conjugation of chlorogenic acid onto graphene oxide through hydrogen bonding and π-π interaction was confirmed by Raman spectroscopy, FTIR analysis and X-ray diffraction patterns. The loading of CA in the nanohybrid was estimated to be around 13.1% by UV-vis spectroscopy. The release profiles showed favourable, sustained and pH-dependent release of CA from CAGO nanocomposite and conformed well to the pseudo-second order kinetic model. Furthermore, the designed anticancer nanohybrid was thermally more stable than its counterpart. The in vitro cytotoxicity results revealed insignificant toxicity effect towards normal cell line, with a viability of >80% even at higher concentration of 50μg/mL. Contrarily, CAGO nanocomposite revealed enhanced toxic effect towards evaluated cancer cell lines (HepG2 human liver hepatocellular carcinoma cell line, A549 human lung adenocarcinoma epithelial cell line, and HeLa human cervical cancer cell line) compared to its free form. Copyright © 2016 Elsevier B.V. All rights reserved.

An Optimized Table-Top Small-Angle X-ray Scattering Set-up for the Nanoscale Structural Analysis of Soft Matter

NASA Astrophysics Data System (ADS)

Sibillano, T.; de Caro, L.; Altamura, D.; Siliqi, D.; Ramella, M.; Boccafoschi, F.; Ciasca, G.; Campi, G.; Tirinato, L.; di Fabrizio, E.; Giannini, C.

2014-11-01

The paper shows how a table top superbright microfocus laboratory X-ray source and an innovative restoring-data algorithm, used in combination, allow to analyze the super molecular structure of soft matter by means of Small Angle X-ray Scattering ex-situ experiments. The proposed theoretical approach is aimed to restore diffraction features from SAXS profiles collected from low scattering biomaterials or soft tissues, and therefore to deal with extremely noisy diffraction SAXS profiles/maps. As biological test cases we inspected: i) residues of exosomes' drops from healthy epithelial colon cell line and colorectal cancer cells; ii) collagen/human elastin artificial scaffolds developed for vascular tissue engineering applications; iii) apoferritin protein in solution. Our results show how this combination can provide morphological/structural nanoscale information to characterize new artificial biomaterials and/or to get insight into the transition between healthy and pathological tissues during the progression of a disease, or to morphologically characterize nanoscale proteins, based on SAXS data collected in a room-sized laboratory.

Design of crossed planar phase grating for metrology

NASA Astrophysics Data System (ADS)

Tang, Yu; Chen, Xinrong; Li, Chaoming; Wang, Rui; Xu, Haiyan; Cheng, Yushui

2018-01-01

Crossed-grating is widely used as the standard element for metrology in two-dimensional precision positioning system. It has many advantages such as high resolution, compact structure, good environmental adaptability and less Abbe error. In this paper, the design of crossed planar reflecting phase grating used under the Littrow condition with circularly polarized light at 780nm wavelength has been carried out. The aim of the design is to find out the range of structure parameters of crossed-grating that has higher -1st order diffraction efficiency and good efficiency equilibrium for both of TE- and TM-polarized incident lights. By adoption of the Fourier modal method (FMM), the microstructure parameters of the 1200lines/mm crossed grating with the duty cycle range of 10% to 50% and the profile depth of 150nm to 350nm have been searched exactly. The calculation results show that: When the duty cycle range of the grating is 42% to 44% and profile depth is 210nm to 220nm, the -1st diffraction efficiencies of TE- and TM-polarized lights are both above 60% and the efficiency equilibrium is better than 80%.

Device and method for creating Gaussian aberration-corrected electron beams

DOEpatents

McMorran, Benjamin; Linck, Martin

2016-01-19

Electron beam phase gratings have phase profiles that produce a diffracted beam having a Gaussian or other selected intensity profile. Phase profiles can also be selected to correct or compensate electron lens aberrations. Typically, a low diffraction order produces a suitable phase profile, and other orders are discarded.

Line spread functions of blazed off-plane gratings operated in the Littrow mounting

NASA Astrophysics Data System (ADS)

DeRoo, Casey T.; McEntaffer, Randall L.; Miles, Drew M.; Peterson, Thomas J.; Marlowe, Hannah; Tutt, James H.; Donovan, Benjamin D.; Menz, Benedikt; Burwitz, Vadim; Hartner, Gisela; Allured, Ryan; Smith, Randall K.; Günther, Ramses; Yanson, Alex; Vacanti, Giuseppe; Ackermann, Marcelo

2016-04-01

Future soft x-ray (10 to 50 Å) spectroscopy missions require higher effective areas and resolutions to perform critical science that cannot be done by instruments on current missions. An x-ray grating spectrometer employing off-plane reflection gratings would be capable of meeting these performance criteria. Off-plane gratings with blazed groove facets operating in the Littrow mounting can be used to achieve excellent throughput into orders achieving high resolutions. We have fabricated two off-plane gratings with blazed groove profiles via a technique that uses commonly available microfabrication processes, is easily scaled for mass production, and yields gratings customized for a given mission architecture. Both fabricated gratings were tested in the Littrow mounting at the Max Planck Institute for Extraterrestrial Physics (MPE) PANTER x-ray test facility to assess their performance. The line spread functions of diffracted orders were measured, and a maximum resolution of 800±20 is reported. In addition, we also observe evidence of a blaze effect from measurements of relative efficiencies of the diffracted orders.

Fingerprinting the type of line edge roughness

NASA Astrophysics Data System (ADS)

Fernández Herrero, A.; Pflüger, M.; Scholze, F.; Soltwisch, V.

2017-06-01

Lamellar gratings are widely used diffractive optical elements and are prototypes of structural elements in integrated electronic circuits. EUV scatterometry is very sensitive to structure details and imperfections, which makes it suitable for the characterization of nanostructured surfaces. As compared to X-ray methods, EUV scattering allows for steeper angles of incidence, which is highly preferable for the investigation of small measurement fields on semiconductor wafers. For the control of the lithographic manufacturing process, a rapid in-line characterization of nanostructures is indispensable. Numerous studies on the determination of regular geometry parameters of lamellar gratings from optical and Extreme Ultraviolet (EUV) scattering also investigated the impact of roughness on the respective results. The challenge is to appropriately model the influence of structure roughness on the diffraction intensities used for the reconstruction of the surface profile. The impact of roughness was already studied analytically but for gratings with a periodic pseudoroughness, because of practical restrictions of the computational domain. Our investigation aims at a better understanding of the scattering caused by line roughness. We designed a set of nine lamellar Si-gratings to be studied by EUV scatterometry. It includes one reference grating with no artificial roughness added, four gratings with a periodic roughness distribution, two with a prevailing line edge roughness (LER) and another two with line width roughness (LWR), and four gratings with a stochastic roughness distribution (two with LER and two with LWR). We show that the type of line roughness has a strong impact on the diffuse scatter angular distribution. Our experimental results are not described well by the present modelling approach based on small, periodically repeated domains.

Interpretations from multichannel seismic-reflection profiles of the deep crust crossing South Carolina and Georgia from the Appalachian Mountains to the Atlantic Coast

USGS Publications Warehouse

Behrendt, John C.

1985-01-01

The Appalachian décollement does not appear continuous from the Appalachian Mountains to the coast but rather appears to extend southeastward only to the Carolina slate belt. A series of reflections on lines S4, S6, and S8 and on the COCORP line is interpreted as evidence of southeastward-dipping imbricate faults, from the Brevard fault on the northwest to beyond the Augusta fault, which marks the southeastern extent of the Eastern Piedmont fault zone. The Carolina slate belt is characterized on the four seismic profiles by a complex series of diffractions and reflections extending from less than 1 s to 8 s. These arrivals are possibly the result of layering in the metasedimentary rocks complexly disrupted by the imbricate faults. A number of Triassic (?) basins are apparent in the reflection data for the rifted Charleston terrane identified from low-gradient magnetic anomalies.

Microstructural characterization of high-manganese austenitic steels with different stacking fault energies

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sato, Shigeo, E-mail: s.sato@imr.tohoku.ac.jp; Kwon, Eui-Pyo; Imafuku, Muneyuki

Microstructures of tensile-deformed high-manganese austenitic steels exhibiting twinning-induced plasticity were analyzed by electron backscatter diffraction pattern observation and X-ray diffraction measurement to examine the influence of differences in their stacking fault energies on twinning activity during deformation. The steel specimen with the low stacking fault energy of 15 mJ/m{sup 2} had a microstructure with a high population of mechanical twins than the steel specimen with the high stacking fault energy (25 mJ/m{sup 2}). The <111> and <100> fibers developed along the tensile axis, and mechanical twinning occurred preferentially in the <111> fiber. The Schmid factors for slip and twinning deformationsmore » can explain the origin of higher twinning activity in the <111> fiber. However, the high stacking fault energy suppresses the twinning activity even in the <111> fiber. A line profile analysis based on the X-ray diffraction data revealed the relationship between the characteristics of the deformed microstructures and the stacking fault energies of the steel specimens. Although the variation in dislocation density with the tensile deformation is not affected by the stacking fault energies, the effect of the stacking fault energies on the crystallite size refinement becomes significant with a decrease in the stacking fault energies. Moreover, the stacking fault probability, which was estimated from a peak-shift analysis of the 111 and 200 diffractions, was high for the specimen with low stacking fault energy. Regardless of the difference in the stacking fault energies of the steel specimens, the refined crystallite size has a certain correlation with the stacking fault probability, indicating that whether the deformation-induced crystallite-size refinement occurs depends directly on the stacking fault probability rather than on the stacking fault energies in the present steel specimens. - Highlights: {yields} We studied effects of stacking fault energies on deformed microstructures of steels. {yields} Correlations between texture and occurrence of mechanical twinning are discussed. {yields} Evolutions of dislocations and crystallite are analyzed by line profile analysis.« less

Transition Region Explosive Events in He II 304Å: Observation and Analysis

NASA Astrophysics Data System (ADS)

Rust, Thomas; Kankelborg, Charles C.

2016-05-01

We present examples of transition region explosive events observed in the He II 304Å spectral line with the Multi Order Solar EUV Spectrograph (MOSES). With small (<5000 km) spatial scale and large non-thermal (100-150 km/s) velocities these events satisfy the observational signatures of transition region explosive events. Derived line profiles show distinct blue and red velocity components with very little broadening of either component. We observe little to no emission from low velocity plasma, making the plasmoid instability reconnection model unlikely as the plasma acceleration mechanism for these events. Rather, the single speed, bi-directional jet characteristics suggested by these data are consistent with acceleration via Petschek reconnection.Observations were made during the first sounding rocket flight of MOSES in 2006. MOSES forms images in 3 orders of a concave diffraction grating. Multilayer coatings largely restrict the passband to the He II 303.8Å and Si XI 303.3Å spectral lines. The angular field of view is about 8.5'x17', or about 20% of the solar disk. These images constitute projections of the volume I(x,y,λ), the intensity as a function of sky plane position and wavelength. Spectral line profiles are recovered via tomographic inversion of these projections. Inversion is carried out using a multiplicative algebraic reconstruction technique.

Beam-smiling in bent-Laue monochromators

NASA Astrophysics Data System (ADS)

Ren, B.; Dilmanian, F. A.; Chapman, L. D.; Wu, X. Y.; Zhong, Z.; Ivanov, I.; Thomlinson, W. C.; Huang, X.

1997-07-01

When a wide fan-shaped x-ray beam is diffracted by a bent crystal in the Laue geometry, the profile of the diffracted beam generally does not appear as a straight line, but as a line with its ends curved up or curved down. This effect, referred to as "beam-smiling", has been a major obstacle in developing bent-Laue crystal monochromators for medical applications of synchrotron x-ray. We modeled a cylindrically bent crystal using the Finite Element Analysis (FEA) method, and we carried out experiments at the National Synchrotron Light Source and Cornell High Energy Synchrotron Source. Our studies show that, while beam-smiling exists in most of the crystal's area because of anticlastic bending effects, there is a region parallel to the bending axis of the crystal where the diffracted beam is "smile-free". By applying asymmetrical bending, this smile-free region can be shifted vertically away from the geometric center of the crystal, as desired. This leads to a novel method of compensating for beam-smiling. We will discuss the method of "differential bending" for smile removal, beam-smiling in the Cauchios and the polychromatic geometry, and the implications of the method on developing single- and double-bent Laue monochromators. The experimental results will be discussed, concentrating on specific beam-smiling observation and removal as applied to the new monochromator of the Multiple Energy Computed Tomography [MECT] project of the Medical Department, Brookhaven National Laboratory.

Modeling and measurements of XRD spectra of extended solids under high pressure

NASA Astrophysics Data System (ADS)

Batyrev, I. G.; Coleman, S. P.; Stavrou, E.; Zaug, J. M.; Ciezak-Jenkins, J. A.

2017-06-01

We present results of evolutionary simulations based on density functional calculations of various extended solids: N-Si and N-H using variable and fixed concentration methods of USPEX. Predicted from the evolutionary simulations structures were analyzed in terms of thermo-dynamical stability and agreement with experimental X-ray diffraction spectra. Stability of the predicted system was estimated from convex-hull plots. X-ray diffraction spectra were calculated using a virtual diffraction algorithm which computes kinematic diffraction intensity in three-dimensional reciprocal space before being reduced to a two-theta line profile. Calculations of thousands of XRD spectra were used to search for a structure of extended solids at certain pressures with best fits to experimental data according to experimental XRD peak position, peak intensity and theoretically calculated enthalpy. Comparison of Raman and IR spectra calculated for best fitted structures with available experimental data shows reasonable agreement for certain vibration modes. Part of this work was performed by LLNL, Contract DE-AC52-07NA27344. We thank the Joint DoD / DOE Munitions Technology Development Program, the HE C-II research program at LLNL and Advanced Light Source, supported by BES DOE, Contract No. DE-AC02-05CH112.

Fluorophore Absorption Size Exclusion Chromatography (FA-SEC): An Alternative Method for High-Throughput Detergent Screening of Membrane Proteins.

PubMed

Lin, Sung-Yao; Sun, Xing-Han; Hsiao, Yu-Hsuan; Chang, Shao-En; Li, Guan-Syun; Hu, Nien-Jen

2016-01-01

Membrane proteins play key roles in many fundamental functions in cells including ATP synthesis, ion and molecule transporter, cell signalling and enzymatic reactions, accounting for ~30% genes of whole genomes. However, the hydrophobic nature of membrane proteins frequently hampers the progress of structure determination. Detergent screening is the critical step in obtaining stable detergent-solubilized membrane proteins and well-diffracting protein crystals. Fluorescence Detection Size Exclusion Chromatography (FSEC) has been developed to monitor the extraction efficiency and monodispersity of membrane proteins in detergent micelles. By tracing the FSEC profiles of GFP-fused membrane proteins, this method significantly enhances the throughput of detergent screening. However, current methods to acquire FSEC profiles require either an in-line fluorescence detector with the SEC equipment or an off-line spectrofluorometer microplate reader. Here, we introduce an alternative method detecting the absorption of GFP (FA-SEC) at 485 nm, thus making this methodology possible on conventional SEC equipment through the in-line absorbance spectrometer. The results demonstrate that absorption is in great correlation with fluorescence of GFP. The comparably weaker absorption signal can be improved by using a longer path-length flow cell. The FA-SEC profiles were congruent with the ones plotted by FSEC, suggesting FA-SEC could be a comparable and economical setup for detergent screening of membrane proteins.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Meimei; Wang, Leyun; Almer, Jonathan D.

Deformation processes in Grade 91 (Fe–9%Cr–1%Mo–V,Nb) and Grade 92 (Fe–9%Cr–0.5%Mo–2%W–V,Nb) ferritic–martensitic steels were investigated at temperatures between 20 and 650 °C using high-energy synchrotron X-ray diffraction with in situ thermal–mechanical loading. The change of the dislocation density with strain was quantified by X-ray diffraction line profile analysis complemented by transmission electron microscopy measurements. The relationship between dislocation density and strain during uniform deformation was described by a dislocation model, and two critical materials parameters, namely dislocation mean free path and dynamic recovery coefficient, were determined as a function of temperature. Effects of alloy chemistry, thermal–mechanical treatment and temperature on themore » tensile deformation process in Grade 91 and Grade 92 steels can be well understood by the dislocation evolution behavior.« less

In situ strain profiling of elastoplastic bending in Ti-6Al-4V alloy by synchrotron energy dispersive x-ray diffraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Croft, M.; National Synchrotron Light Source, Brookhaven National Laboratory, Upton, New York 11973; Shukla, V.

Elastic and plastic strain evolution under four-point bending has been studied by synchrotron energy dispersive x-ray diffraction. Measured strain profiles across the specimen thickness showed an increasing linear elastic strain gradient under increasing four-point bending load up to approx2 kN. The bulk elastic modulus of Ti-6Al-4V was determined as 118 GPa. The onset of plastic deformation was found to set in at a total in-plane strain of approx0.008, both under tension and compression. Plastic deformation under bending is initiated in the vicinity of the surface and at a stress of 1100 MPa, and propagates inward, while a finite core regionmore » remains elastically deformed up to 3.67 kN loading. The onset of the plastic regime and the plastic regime itself has been verified by monitoring the line broadening of the (100) peak of alpha-Ti. The effective compression/tension stress-strain curve has been obtained from the scaling collapse of strain profile data taken at seven external load levels. A similar multiple load scaling collapse of the plastic strain variation has also been obtained. The level of precision in strain measurement reported herein was evaluated and found to be 1.5x10{sup -5} or better.« less

Evaluation of Argon ion irradiation hardening of ferritic/martensitic steel-T91 using nanoindentation, X-ray diffraction and TEM techniques

NASA Astrophysics Data System (ADS)

Naveen Kumar, N.; Tewari, R.; Mukherjee, P.; Gayathri, N.; Durgaprasad, P. V.; Taki, G. S.; Krishna, J. B. M.; Sinha, A. K.; Pant, P.; Revally, A. K.; Dutta, B. K.; Dey, G. K.

2017-08-01

In the present study, microstructures of Ferritic-martensitic T-91 steel irradiated at room temperature for 5, 10 and 20 dpa using 315 KeV Ar+9 ions have been characterized by grazing incident X-ray diffraction (GIXRD) and by transmission electron microscopy (TEM). Line profiles of GIXRD patterns have shown that the size of domain continuously reduced with increasing dose of radiation. TEM investigations of irradiated samples have shown the presence of black dots, the number density of which decreases with increasing dose. Microstructures of irradiated samples have also revealed the presence of point defect clusters, such as dislocation loops and bubbles. In addition, dissolution of precipitates due to irradiation was also observed. Nano-indentation studies on the irradiated samples have shown saturation behavior in hardness as a function of dose which could be correlated with the changes in the yield strength of the alloy.

Airy Wave Packets Accelerating in Space-Time

NASA Astrophysics Data System (ADS)

Kondakci, H. Esat; Abouraddy, Ayman F.

2018-04-01

Although diffractive spreading is an unavoidable feature of all wave phenomena, certain waveforms can attain propagation invariance. A lesser-explored strategy for achieving optical self-similar propagation exploits the modification of the spatiotemporal field structure when observed in reference frames moving at relativistic speeds. For such an observer, it is predicted that the associated Lorentz boost can bring to a halt the axial dynamics of a wave packet of an arbitrary profile. This phenomenon is particularly striking in the case of a self-accelerating beam—such as an Airy beam—whose peak normally undergoes a transverse displacement upon free propagation. Here we synthesize an acceleration-free Airy wave packet that travels in a straight line by deforming its spatiotemporal spectrum to reproduce the impact of a Lorentz boost. The roles of the axial spatial coordinate and time are swapped, leading to "time diffraction" manifested in self-acceleration observed in the propagating Airy wave-packet frame.

Understanding self ion damage in FCC Ni-Cr-Fe based alloy using X-ray diffraction techniques

NASA Astrophysics Data System (ADS)

Halder Banerjee, R.; Sengupta, P.; Chatterjee, A.; Mishra, S. C.; Bhukta, A.; Satyam, P. V.; Samajdar, I.; Dey, G. K.

2018-04-01

Using X-ray diffraction line profile analysis (XRDLPA) approach the radiation response of FCC Ni-Cr-Fe based alloy 690 to 1.5 and 3 MeV Ni2+ ion damage was quantified in terms of its microstructural parameters. These microstructural parameters viz. average domain size, microstrain and dislocation density were found to vary anisotropically with fluence. The anisotropic behaviour is mainly attributable to presence of twins in pre-irradiated microstructure. After irradiation, surface roughness increases as a function of fluence attributable to change in surface and sub-surface morphology caused by displacement cascade, defects and sputtered atoms created by incident energetic ion. The radiation hardening in case of 1.5 MeV Ni2+ irradiated specimens too is a consequence of the increase in dislocation density formed by interaction of radiation induced defects with pre-existing dislocations. At highest fluence there is an initiation of saturation.

Self-interference of split HOLZ line (SIS-HOLZ) for z-dependent atomic displacement measurement: Theoretical discussion.

PubMed

Norouzpour, Mana; Rakhsha, Ramtin; Herring, Rodney

2017-06-01

A characteristic of the majority of semiconductors is the presence of lattice strain varying with the nanometer scale. Strain originates from the lattice mismatch between layers of different composition deposited during epitaxial growth. Strain can increase the mobility of the charge carriers by the band gap reduction. So, measuring atomic displacement inside crystals is an important field of interest in semiconductor industry. Among all available transmission electron microscopy techniques offering nano-scale resolution measurements, convergent beam electron diffraction (CBED) patterns show the highest sensitivity to the atomic displacement. Higher Order Laue Zone (HOLZ) lines split by small non-uniform variations of lattice constant allowing to measure the atomic displacement through the crystal. However, it could only reveal the atomic displacement in two dimensions, i.e., within the x-y plane of the thin film of TEM specimen. The z-axis atomic displacement which is along the path of the electron beam has been missing. This information can be obtained by recovering the phase information across the split HOLZ line using the self-interference of the split HOLZ line (SIS-HOLZ). In this work, we report the analytical approach used to attain the phase profile across the split HOLZ line. The phase profile is studied for three different atomic displacement fields in the Si substrate at 80nm away from its interface with Si/Si 0.8 Ge 0.2 superlattices. Copyright © 2017 Elsevier Ltd. All rights reserved.

Precision sizing of moving large particles using diffraction splitting of Doppler lines

NASA Astrophysics Data System (ADS)

Kononenko, Vadim L.

1999-02-01

It is shown, that the Doppler line from a single large particle moving with a constant velocity through a finite- width laser beam, undergoes a doublet-type splitting under specific observation conditions. A general requirement is that particle size 2a is not negligibly small, compared with beam diameter 2w$0. Three optical mechanisms of line splitting are considered. The first one is based on nonsymmetric diffraction of a bounded laser beam by a moving particle. The second arises from the transient geometry of diffraction. The third mechanism, of photometric nature, originates from specific time variation of total illuminance of moving particles when 2a>Lambda, the interference fringe spacing in the measuring volume. The diffraction splitting is observed when a detector is placed near one of diffraction minima corresponding to either of probing beams, and 2a equals (n0.5)Lambda for n equals 1,2. The photometric splitting is observed with an image-forming optics, when 2a equals n(Lambda) . That gives the possibility of distant particles sizing based on the Doppler line splitting phenomenon. A general theory of line splitting is developed, and used to explain the experimental observations quantitatively. The influence of the scattering angels and observation angle on the line splitting characteristics is studied analytically and numerically.

Optimised Combined Angular and Energy Dispersive Diffraction at the PSICHE Beam Line of the SOLEIL Synchrotron for Fast, High Q-range Structure Determination at High Pressure and Temperature.

NASA Astrophysics Data System (ADS)

King, A.; Guignot, N.; Boulard, E.; Deslandes, J. P.; Clark, A. N.; Morard, G.; Itié, J. P.

2017-12-01

Synchrotron diffraction is an ideal technique for investigating materials at high pressure and temperature, because the penetrating nature of high-energy X-rays allows measurements to be made inside pressure cells or sample environments. Wang et al. described the CAESAR acquisition strategy, in which energy and angular dispersive techniques are combined to produce an instrument particularly suitable for quantitative measurements from samples inside high-pressure apparati [1]. The PSICHE beam line of the SOLEIL Synchrotron is equipped with such a CAESAR system. Uniquely, this system allows energy dispersive diffraction spectra to be acquired at scattering angles between -5 and +30 degrees two theta, while maintaining a sphere of confusion at the measurement position in the order of 10 microns. The slits used to define the scattering angle act as Soller slits and select the diffracted volume, separating the sample from its environment. By developing an optimised acquisition strategy we are able to obtain data covering a very wide Q range (to 160nm-1 or more), while minimising the total acquisition time (one hour per complete acquisition). In addition, the 2D nature (angle and energy) of the acquired dataset enables the effective incident spectrum to be efficiently determined with no addition measurements, in order to normalise the acquired data. The resulting profile of scattered intensity as a function of Q is suitable for Fourier transform analysis of liquid or amorphous structures. PSICHE is a multi technique beam line, with a part of the beam time dedicated to parallel beam absorption and phase contrast radiography and tomography [2]. Examples will be given to show how these techniques can be combined with diffraction techniques to greatly enrich studies of materials at extreme conditions. [1] Wang, Y., Uchida, T., Von Dreele, R., Rivers, M. L., Nishiyama, N., Funakoshi, K., Nozawa, A., and Keneko, H., J. Appl. Crystallogr. 37, 947 (2004). [2] King, A., Guignot, N., Zerbino, P., Boulard, E., Desjardins, K., Bourdessoule, M., Leclerq, N., Le, S., Renaud, G., Cerato, M., Bornert, M., Lenoir, N., Delzon, S., Perrillat, J.-P., Legodec, Y., Itié, J.-P. Rev. Sci. Instrum. 87, 093704 (2016).

Fast ultrasonic wavelength tuning in X-ray experiment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blagov, A. E., E-mail: blagov-ae@mail.ru; Pisarevskii, Yu. V.; Koval’chuk, M. V.

2016-03-15

A method of tuning (scanning) X-ray beam wavelength based on modulation of the lattice parameter of X-ray optical crystal by an ultrasonic standing wave excited in it has been proposed and experimentally implemented. The double-crystal antiparallel scheme of X-ray diffraction, in which an ultrasonic wave is excited in the second crystal, is used in the experiment. The profile of characteristic line k{sub α1} of an X-ray tube with a molybdenum anode is recorded using both the proposed tuning scheme and conventional mechanical rotation of crystal. The results obtained by both techniques are in good agreement.

Profilometric characterization of DOEs with continuous microrelief

NASA Astrophysics Data System (ADS)

Korolkov, V. P.; Ostapenko, S. V.; Shimansky, R. V.

2008-09-01

Methodology of local characterization of continuous-relief diffractive optical elements has been discussed. The local profile depth can be evaluated using "approximated depth" defined without taking a profile near diffractive zone boundaries into account. Several methods to estimate the approximated depth have been offered.

Illicit drug detection using energy dispersive x-ray diffraction

NASA Astrophysics Data System (ADS)

Cook, E. J.; Griffiths, J. A.; Koutalonis, M.; Gent, C.; Pani, S.; Horrocks, J. A.; George, L.; Hardwick, S.; Speller, R.

2009-05-01

Illicit drugs are imported into countries in myriad ways, including via the postal system and courier services. An automated system is required to detect drugs in parcels for which X-ray diffraction is a suitable technique as it is non-destructive, material specific and uses X-rays of sufficiently high energy to penetrate parcels containing a range of attenuating materials. A database has been constructed containing the measured powder diffraction profiles of several thousand materials likely to be found in parcels. These include drugs, cutting agents, packaging and other innocuous materials. A software model has been developed using these data to predict the diffraction profiles which would be obtained by X-ray diffraction systems with a range of suggested detector (high purity germanium, CZT and scintillation), source and collimation options. The aim of the model was to identify the most promising system geometries, which was done with the aid of multivariate analysis (MVA). The most promising systems were constructed and tested. The diffraction profiles of a range of materials have been measured and used to both validate the model and to identify the presence of drugs in sample packages.

Nondestructive strain depth profiling with high energy X-ray diffraction: System capabilities and limitations

NASA Astrophysics Data System (ADS)

Zhang, Zhan; Wendt, Scott; Cosentino, Nicholas; Bond, Leonard J.

2018-04-01

Limited by photon energy, and penetration capability, traditional X-ray diffraction (XRD) strain measurements are only capable of achieving a few microns depth due to the use of copper (Cu Kα1) or molybdenum (Mo Kα1) characteristic radiation. For deeper strain depth profiling, destructive methods are commonly necessary to access layers of interest by removing material. To investigate deeper depth profiles nondestructively, a laboratory bench-top high-energy X-ray diffraction (HEXRD) system was previously developed. This HEXRD method uses an industrial 320 kVp X-Ray tube and the Kα1 characteristic peak of tungsten, to produces a higher intensity X-ray beam which enables depth profiling measurement of lattice strain. An aluminum sample was investigated with deformation/load provided using a bending rig. It was shown that the HEXRD method is capable of strain depth profiling to 2.5 mm. The method was validated using an aluminum sample where both the HEXRD method and the traditional X-ray diffraction method gave data compared with that obtained using destructive etching layer removal, performed by a commercial provider. The results demonstrate comparable accuracy up to 0.8 mm depth. Nevertheless, higher attenuation capabilities in heavier metals limit the applications in other materials. Simulations predict that HEXRD works for steel and nickel in material up to 200 µm, but experiment results indicate that the HEXRD strain profile is not practical for steel and nickel material, and the measured diffraction signals are undetectable when compared to the noise.

Observation of electromigration in a Cu thin line by in situ coherent x-ray diffraction microscopy

NASA Astrophysics Data System (ADS)

Takahashi, Yukio; Nishino, Yoshinori; Furukawa, Hayato; Kubo, Hideto; Yamauchi, Kazuto; Ishikawa, Tetsuya; Matsubara, Eiichiro

2009-06-01

Electromigration (EM) in a 1-μm-thick Cu thin line was investigated by in situ coherent x-ray diffraction microscopy (CXDM). Characteristic x-ray speckle patterns due to both EM-induced voids and thermal deformation in the thin line were observed in the coherent x-ray diffraction patterns. Both parts of the voids and the deformation were successfully visualized in the images reconstructed from the diffraction patterns. This result not only represents the first demonstration of the visualization of structural changes in metallic materials by in situ CXDM but is also an important step toward studying the structural dynamics of nanomaterials using x-ray free-electron lasers in the near future.

Through-Thickness Residual Stress Profiles in Austenitic Stainless Steel Welds: A Combined Experimental and Prediction Study

NASA Astrophysics Data System (ADS)

Mathew, J.; Moat, R. J.; Paddea, S.; Francis, J. A.; Fitzpatrick, M. E.; Bouchard, P. J.

2017-12-01

Economic and safe management of nuclear plant components relies on accurate prediction of welding-induced residual stresses. In this study, the distribution of residual stress through the thickness of austenitic stainless steel welds has been measured using neutron diffraction and the contour method. The measured data are used to validate residual stress profiles predicted by an artificial neural network approach (ANN) as a function of welding heat input and geometry. Maximum tensile stresses with magnitude close to the yield strength of the material were observed near the weld cap in both axial and hoop direction of the welds. Significant scatter of more than 200 MPa was found within the residual stress measurements at the weld center line and are associated with the geometry and welding conditions of individual weld passes. The ANN prediction is developed in an attempt to effectively quantify this phenomenon of `innate scatter' and to learn the non-linear patterns in the weld residual stress profiles. Furthermore, the efficacy of the ANN method for defining through-thickness residual stress profiles in welds for application in structural integrity assessments is evaluated.

Diffractive optical elements for transformation of modes in lasers

DOEpatents

Sridharan, Arun K.; Pax, Paul H.; Heebner, John E.; Drachenberg, Derrek R.; Armstrong, James P.; Dawson, Jay W.

2015-09-01

Spatial mode conversion modules are described, with the capability of efficiently transforming a given optical beam profile, at one plane in space into another well-defined optical beam profile at a different plane in space, whose detailed spatial features and symmetry properties can, in general, differ significantly. The modules are comprised of passive, high-efficiency, low-loss diffractive optical elements, combined with Fourier transform optics. Design rules are described that employ phase retrieval techniques and associated algorithms to determine the necessary profiles of the diffractive optical components. System augmentations are described that utilize real-time adaptive optical techniques for enhanced performance as well as power scaling.

Diffractive optical elements for transformation of modes in lasers

DOEpatents

Sridharan, Arun K; Pax, Paul H; Heebner, John E; Drachenberg, Derrek R.; Armstrong, James P.; Dawson, Jay W.

2016-06-21

Spatial mode conversion modules are described, with the capability of efficiently transforming a given optical beam profile, at one plane in space into another well-defined optical beam profile at a different plane in space, whose detailed spatial features and symmetry properties can, in general, differ significantly. The modules are comprised of passive, high-efficiency, low-loss diffractive optical elements, combined with Fourier transform optics. Design rules are described that employ phase retrieval techniques and associated algorithms to determine the necessary profiles of the diffractive optical components. System augmentations are described that utilize real-time adaptive optical techniques for enhanced performance as well as power scaling.

Method of fabricating reflection-mode EUV diffraction elements

DOEpatents

Naulleau, Patrick P.

2002-01-01

Techniques for fabricating a well-controlled, quantized-level, engineered surface that serves as substrates for EUV reflection multilayer overcomes problems associated with the fabrication of reflective EUV diffraction elements. The technique when employed to fabricate an EUV diffraction element that includes the steps of: (a) forming an etch stack comprising alternating layers of first and second materials on a substrate surface where the two material can provide relative etch selectivity; (b) creating a relief profile in the etch stack wherein the relief profile has a defined contour; and (c) depositing a multilayer reflection film over the relief profile wherein the film has an outer contour that substantially matches that of the relief profile. For a typical EUV multilayer, if the features on the substrate are larger than 50 nm, the multilayer will be conformal to the substrate. Thus, the phase imparted to the reflected wavefront will closely match that geometrically set by the surface height profile.

Analysis of energy dispersive x-ray diffraction profiles for material identification, imaging and system control

NASA Astrophysics Data System (ADS)

Cook, Emily Jane

2008-12-01

This thesis presents the analysis of low angle X-ray scatter measurements taken with an energy dispersive system for substance identification, imaging and system control. Diffraction measurements were made on illicit drugs, which have pseudo- crystalline structures and thus produce diffraction patterns comprising a se ries of sharp peaks. Though the diffraction profiles of each drug are visually characteristic, automated detection systems require a substance identification algorithm, and multivariate analysis was selected as suitable. The software was trained with measured diffraction data from 60 samples covering 7 illicit drugs and 5 common cutting agents, collected with a range of statistical qual ities and used to predict the content of 7 unknown samples. In all cases the constituents were identified correctly and the contents predicted to within 15%. Soft tissues exhibit broad peaks in their diffraction patterns. Diffraction data were collected from formalin fixed breast tissue samples and used to gen erate images. Maximum contrast between healthy and suspicious regions was achieved using momentum transfer windows 1.04-1.10 and 1.84-1.90 nm_1. The resulting images had an average contrast of 24.6% and 38.9% compared to the corresponding transmission X-ray images (18.3%). The data was used to simulate the feedback for an adaptive imaging system and the ratio of the aforementioned momentum transfer regions found to be an excellent pa rameter. Investigation into the effects of formalin fixation on human breast tissue and animal tissue equivalents indicated that fixation in standard 10% buffered formalin does not alter the diffraction profiles of tissue in the mo mentum transfer regions examined, though 100% unbuffered formalin affects the profile of porcine muscle tissue (a substitute for glandular and tumourous tissue), though fat is unaffected.

Work Hardening, Dislocation Structure, and Load Partitioning in Lath Martensite Determined by In Situ Neutron Diffraction Line Profile Analysis

NASA Astrophysics Data System (ADS)

Harjo, Stefanus; Kawasaki, Takuro; Tomota, Yo; Gong, Wu; Aizawa, Kazuya; Tichy, Geza; Shi, Zengmin; Ungár, Tamas

2017-09-01

A lath martensite steel containing 0.22 mass pct carbon was analyzed in situ during tensile deformation by high-resolution time-of-flight neutron diffraction to clarify the large work-hardening behavior at the beginning of plastic deformation. The diffraction peaks in plastically deformed states exhibit asymmetries as the reflection of redistributions of the stress and dislocation densities/arrangements in two lath packets: soft packet, where the dislocation glides are favorable, and hard packet, where they are unfavorable. The dislocation density was as high as 1015 m-2 in the as-heat-treated state. During tensile straining, the load and dislocation density became different between the two lath packets. The dislocation character and arrangement varied in the hard packet but hardly changed in the soft packet. In the hard packet, dislocations that were mainly screw-type in the as-heat-treated state became primarily edge-type and rearranged towards a dipole character related to constructing cell walls. The hard packet played an important role in the work hardening in martensite, which could be understood by considering the increase in dislocation density along with the change in dislocation arrangement.

Quantitative evaluation of high-resolution features in images of negatively stained Tobacco Mosaic Virus.

PubMed

Chang, C F; Williams, R C; Grano, D A; Downing, K H; Glaeser, R M

1983-01-01

This study investigates the causes of the apparent differences between the optical diffraction pattern of a micrograph of a Tobacco Mosaic Virus (TMV) particle, the optical diffraction pattern of a ten-fold photographically averaged image, and the computed diffraction pattern of the original micrograph. Peak intensities along the layer lines in the transform of the averaged image appear to be quite unlike those in the diffraction pattern of the original micrograph, and the diffraction intensities for the averaged image extend to unexpectedly high resolution. A carefully controlled, quantitative comparison reveals, however, that the optical diffraction pattern of the original micrograph and that of the ten-fold averaged image are essentially equivalent. Using computer-based image processing, we discovered that the peak intensities on the 6th layer line have values very similar in magnitude to the neighboring noise, in contrast to what was expected from the optical diffraction pattern of the original micrograph. This discrepancy was resolved by recording a series of optical diffraction patterns when the original micrograph was immersed in oil. These patterns revealed the presence of a substantial phase grating effect, which exaggerated the peak intensities on the 6th layer line, causing an erroneous impression that the high resolution features possessed a good signal-to-noise ratio. This study thus reveals some pitfalls and misleading results that can be encountered when using optical diffraction patterns to evaluate image quality.

The measurement capabilities of cross-sectional profile of Nanoimprint template pattern using small angle x-ray scattering

NASA Astrophysics Data System (ADS)

Yamanaka, Eiji; Taniguchi, Rikiya; Itoh, Masamitsu; Omote, Kazuhiko; Ito, Yoshiyasu; Ogata, Kiyoshi; Hayashi, Naoya

2016-05-01

Nanoimprint lithography (NIL) is one of the most potential candidates for the next generation lithography for semiconductor. It will achieve the lithography with high resolution and low cost. High resolution of NIL will be determined by a high definition template. Nanoimprint lithography will faithfully transfer the pattern of NIL template to the wafer. Cross-sectional profile of the template pattern will greatly affect the resist profile on the wafer. Therefore, the management of the cross-sectional profile is essential. Grazing incidence small angle x-ray scattering (GI-SAXS) technique has been proposed as one of the method for measuring cross-sectional profile of periodic nanostructure pattern. Incident x-rays are irradiated to the sample surface with very low glancing angle. It is close to the critical angle of the total reflection of the x-ray. The scattered x-rays from the surface structure are detected on a two-dimensional detector. The observed intensity is discrete in the horizontal (2θ) direction. It is due to the periodicity of the structure, and diffraction is observed only when the diffraction condition is satisfied. In the vertical (β) direction, the diffraction intensity pattern shows interference fringes reflected to height and shape of the structure. Features of the measurement using x-ray are that the optical constant for the materials are well known, and it is possible to calculate a specific diffraction intensity pattern based on a certain model of the cross-sectional profile. The surface structure is estimated by to collate the calculated diffraction intensity pattern that sequentially while changing the model parameters with the measured diffraction intensity pattern. Furthermore, GI-SAXS technique can be measured an object in a non-destructive. It suggests the potential to be an effective tool for product quality assurance. We have developed a cross-sectional profile measurement of quartz template pattern using GI-SAXS technique. In this report, we will report the measurement capabilities of GI-SAXS technique as a cross-sectional profile measurement tool of NIL quartz template pattern.

Spatial-phase-modulation-based study of polyvinyl-alcohol/acrylamide photopolymers in the low spatial frequency range.

PubMed

Gallego, Sergi; Márquez, André; Méndez, David; Marini, Stephan; Beléndez, Augusto; Pascual, Inmaculada

2009-08-01

Photopolymers are appealing materials for the fabrication of diffractive optical elements (DOEs). We evaluate the possibilities of polyvinyl-alcohol/acrylamide-based photopolymers to store diffractive elements with low spatial frequencies. We record gratings with different spatial frequencies in the material and analyze the material behavior measuring the transmitted and the reflected orders as a function of exposition. We study two different compositions for the photopolymer, with and without a cross-linker. The values of diffraction efficiency achieved for both compositions make the material suitable to record DOEs with long spatial periods. Assuming a Fermi-Dirac-function-based profile, we fitted the diffracted intensities (up to the eighth order) to obtain the phase profile of the recorded gratings. This analysis shows that it is possible to achieve a phase shift larger than 2pi rad with steep edges in the periodic phase profile. In the case of the measurements in reflection, we have obtained information dealing with the surface profile, which show that it has a smooth shape with an extremely large phase-modulation depth.

Diffraction-analysis-based characterization of very fine gratings

NASA Astrophysics Data System (ADS)

Bischoff, Joerg; Truckenbrodt, Horst; Bauer, Joachim J.

1997-09-01

Fine gratings with spatial periods below one micron, either ruled mechanically or patterned holographically, play a key role as encoders in high precision translational or rotational coordinate or measuring machines. Besides, the fast in-line characterization of submicron patterns is a stringent demand in recent microelectronic technology. Thus, a rapid, destruction free and highly accurate measuring technique is required to ensure the quality during manufacturing and for final testing. We propose an optical method which was already successfully introduced in semiconductor industry. Here, the inverse scatter problem inherent in this diffraction based approach is overcome by sophisticated data analysis such as multivariate regression or neural networks. Shortly sketched, the procedure is as follows: certain diffraction efficiencies are measured with an optical angle resolved scatterometer and assigned to a number of profile parameters via data analysis (prediction). Before, the specific measuring model has to be calibrated. If the wavelength-to-period rate is well below unity, it is quite easy to gather enough diffraction orders. However, for gratings with spatial periods being smaller than the probing wavelength, merely the specular reflex will propagate for perpendicular incidence (zero order grating). Consequently, it is virtually impossible to perform a regression analysis. A proper mean to tackle this bottleneck is to record the zero-order reflex as a function of the incident angle. In this paper, the measurement of submicron gratings is discussed with the examples of 0.8, 1.0 and 1.4 micron period resist gratings on silicon, etched silicon oxide on silicon (same periods) and a 512 nm pitch chromium grating on quartz. Using a He-Ne laser with 633 nm wavelength and measuring the direct reflex in both linear polarizations, it is shown that even submicron patterning processes can be monitored and the resulting profiles with linewidths below a half micron can be characterized reliably with 2(theta) - scatterometry.

Line profile analysis of ODS steels Fe20Cr5AlTiY milled powders at different Y2O3 concentrations

NASA Astrophysics Data System (ADS)

Afandi, A.; Nisa, R.; Thosin, K. A. Z.

2017-04-01

Mechanical properties of material are largely dictated by constituent microstructure parameters such as dislocation density, lattice microstrain, crystallite size and its distribution. To develop ultra-fine grain alloys such as Oxide Dispersion Strengthened (ODS) alloys, mechanical alloying is crucial step to introduce crystal defects, and refining the crystallite size. In this research the ODS sample powders were mechanically alloyed with different Y2O3 concentration respectively of 0.5, 1, 3, and 5 wt%. MA process was conducted with High Energy Milling (HEM) with the ball to powder ratio of 15:1. The vial and the ball were made of alumina, and the milling condition is set 200 r.p.m constant. The ODS powders were investigated by X-Ray Diffractions (XRD), Bragg-Brentano setup of SmartLab Rigaku with 40 KV, and 30 mA, step size using 0.02°, with scanning speed of 4°min-1. Line Profile Analysis (LPA) of classical Williamson-Hall was carried out, with the aim to investigate the different crystallite size, and microstrain due to the selection of the full wide at half maximum (FWHM) and integral breadth.

Diffraction in volume reflection gratings with variable fringe contrast.

PubMed

Brotherton-Ratcliffe, David; Bjelkhagen, Hans; Osanlou, Ardeshir; Excell, Peter

2015-06-01

The PSM model is used to analyze the process of diffraction occurring in volume reflection gratings in which fringe contrast is an arbitrary function of distance within the grating. General analytic expressions for diffraction efficiency at Bragg resonance are obtained for unslanted panchromatic lossless reflection gratings at oblique incidence. These formulas are then checked for several diverse fringe contrast profiles with numerical solutions of the Helmholtz equation, where exceptionally good agreement is observed. Away from Bragg resonance, the case of the hyperbolically decaying fringe contrast profile is shown to lead to an analytic expression for the diffraction efficiency and this is again compared successfully with numerical solutions of the Helmholtz equation.

Synthesis, structure and cytotoxic activity of acetylenic derivatives of betulonic and betulinic acids

NASA Astrophysics Data System (ADS)

Bębenek, Ewa; Chrobak, Elwira; Wietrzyk, Joanna; Kadela, Monika; Chrobak, Artur; Kusz, Joachim; Książek, Maria; Jastrzębska, Maria; Boryczka, Stanisław

2016-02-01

A series of acetylenic derivatives of betulonic and betulinic acids has been synthesized and characterized by 1H and 13C NMR, IR and MS spectroscopy. The structure of propargyl betulonate 4 and propargyl betulinate-DMF solvate 8A was solved by X-ray diffraction. Thermal properties were examined using a DSC technique. The resulting alkynyl derivatives, as well as betulin 1 and betulinic acid 3, were evaluated in vitro for their cytotoxic activity against human T47D breast cancer, CCRF/CEM leukemia, SW707 colorectal, murine P388 leukemia and BALB3T3 normal fibroblasts cell lines. Several of the obtained compounds have a favorable cytotoxic profile than betulin 1. Propargyl betulinate 8 was the most active derivative, being up to 3-fold more potent than betulin 1 against the human leukemia (CCRF/CEM) cell line, with an IC50 value of 3.9 μg/mL.

The High Resolution Powder Diffraction Beam Line at ESRF.

PubMed

Fitch, A N

2004-01-01

The optical design and performance of the high-resolution powder diffraction beam line BM16 at ESRF are discussed and illustrated. Some recent studies carried out on BM16 are described, including crystal structure solution and refinement, anomalous scattering, in situ measurements, residual strain in engineering components, investigation of microstructure, and grazing-incidence diffraction from surface layers. The beam line is built on a bending magnet, and operates in the energy range from 5 keV to 40 keV. After the move to an undulator source in 2002, it will benefit from an extented energy range up to 60 keV and increased flux and resolution. It is anticipated that enhancements to the data quality will be achieved, leading to the solution of larger crystal structures, and improvements in the accuracy of refined structures. The systematic exploitation of anisotropic thermal expansion will help reduce the effects of peak overlap in the analysis of powder diffraction data.

Macromolecular Topography Leaps into the Digital Age

NASA Technical Reports Server (NTRS)

Lovelace, J.; Bellamy, H.; Snell, E. H.; Borgstahl, G.

2003-01-01

A low-cost, real-time digital topography system is under development which will replace x-ray film and nuclear emulsion plates. The imaging system is based on an inexpensive surveillance camera that offers a 1000x1000 array of 8 im square pixels, anti-blooming circuitry, and very quick read out. Currently, the system directly converts x-rays to an image with no phosphor. The system is small and light and can be easily adapted to work with other crystallographic equipment. Preliminary images have been acquired of cubic insulin at the NSLS x26c beam line. NSLS x26c was configured for unfocused monochromatic radiation. Six reflections were collected with stills spaced from 0.002 to 0.001 degrees apart across the entire oscillation range that the reflections were in diffracting condition. All of the reflections were rotated to the vertical to reduce Lorentz and beam related effects. This particular CCD is designed for short exposure applications (much less than 1 sec) and so has a relatively high dark current leading to noisy raw images. The images are processed to remove background and other system noise with a multi-step approach including the use of wavelets, histogram, and mean window filtering. After processing, animations were constructed with the corresponding reflection profile to show the diffraction of the crystal volume vs. the oscillation angle as well as composite images showing the parts of the crystal with the strongest diffraction for each reflection. The final goal is to correlate features seen in reflection profiles captured with fine phi slicing to those seen in the topography images. With this development macromolecular topography finally comes into the digital age.

Nanostructure Diffraction Gratings for Integrated Spectroscopy and Sensing

NASA Technical Reports Server (NTRS)

Guo, Junpeng (Inventor)

2015-01-01

The present disclosure pertains to metal or dielectric nanostructures of the subwavelength scale within the grating lines of optical diffraction gratings. The nanostructures have surface plasmon resonances or non-plasmon optical resonances. A linear photodetector array is used to capture the resonance spectra from one of the diffraction orders. The combined nanostructure super-grating and photodetector array eliminates the use of external optical spectrometers for measuring surface plasmon or optical resonance frequency shift caused by the presence of chemical and biological agents. The nanostructure super-gratings can be used for building integrated surface enhanced Raman scattering (SERS) spectrometers. The nanostructures within the diffraction grating lines enhance Raman scattering signal light while the diffraction grating pattern of the nanostructures diffracts Raman scattering light to different directions of propagation according to their wavelengths. Therefore, the nanostructure super-gratings allows for the use of a photodetector array to capture the surface enhanced Raman scattering spectra.

Nanostructure Diffraction Gratings for Integrated Spectroscopy and Sensing

NASA Technical Reports Server (NTRS)

Guo, Junpeng (Inventor)

2016-01-01

The present disclosure pertains to metal or dielectric nanostructures of the subwavelength scale within the grating lines of optical diffraction gratings. The nanostructures have surface plasmon resonances or non-plasmon optical resonances. A linear photodetector array is used to capture the resonance spectra from one of the diffraction orders. The combined nanostructure super-grating and photodetector array eliminates the use of external optical spectrometers for measuring surface plasmon or optical resonance frequency shift caused by the presence of chemical and biological agents. The nanostructure super-gratings can be used for building integrated surface enhanced Raman scattering (SERS) spectrometers. The nanostructures within the diffraction grating lines enhance Raman scattering signal light while the diffraction grating pattern of the nanostructures diffracts Raman scattering light to different directions of propagation according to their wavelengths. Therefore, the nanostructure super-gratings allows for the use of a photodetector array to capture the surface enhanced Raman scattering spectra.

Quantitative phase analysis and microstructure characterization of magnetite nanocrystals obtained by microwave assisted non-hydrolytic sol–gel synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sciancalepore, Corrado, E-mail: corrado.sciancalepore@unimore.it; Bondioli, Federica; INSTM Consortium, Via G. Giusti 9, 51121 Firenze

2015-02-15

An innovative preparation procedure, based on microwave assisted non-hydrolytic sol–gel synthesis, to obtain spherical magnetite nanoparticles was reported together with a detailed quantitative phase analysis and microstructure characterization of the synthetic products. The nanoparticle growth was analyzed as a function of the synthesis time and was described in terms of crystallization degree employing the Rietveld method on the magnetic nanostructured system for the determination of the amorphous content using hematite as internal standard. Product crystallinity increases as the microwave thermal treatment is increased and reaches very high percentages for synthesis times longer than 1 h. Microstructural evolution of nanocrystals wasmore » followed by the integral breadth methods to obtain information on the crystallite size-strain distribution. The results of diffraction line profile analysis were compared with nanoparticle grain distribution estimated by dimensional analysis of the transmission electron microscopy (TEM) images. A variation both in the average grain size and in the distribution of the coherently diffraction domains is evidenced, allowing to suppose a relationship between the two quantities. The traditional integral breadth methods have proven to be valid for a rapid assessment of the diffraction line broadening effects in the above-mentioned nanostructured systems and the basic assumption for the correct use of these methods are discussed as well. - Highlights: • Fe{sub 3}O{sub 4} nanocrystals were obtained by MW-assisted non-hydrolytic sol–gel synthesis. • Quantitative phase analysis revealed that crystallinity up to 95% was reached. • The strategy of Rietveld refinements was discussed in details. • Dimensional analysis showed nanoparticles ranging from 4 to 8 nm. • Results of integral breadth methods were compared with microscopic analysis.« less

Effects of limestone petrography and calcite microstructure on OPC clinker raw meals burnability

NASA Astrophysics Data System (ADS)

Galimberti, Matteo; Marinoni, Nicoletta; Della Porta, Giovanna; Marchi, Maurizio; Dapiaggi, Monica

2017-10-01

Limestone represents the main raw material for ordinary Portland cement clinker production. In this study eight natural limestones from different geological environments were chosen to prepare raw meals for clinker manufacturing, aiming to define a parameter controlling the burnability. First, limestones were characterized by X-Ray Fluorescence, X-Ray Powder Diffraction and Optical Microscopy to assess their suitability for clinker production and their petrographic features. The average domains size and the microstrain of calcite were also determined by X-Ray Powder Diffraction line profile analysis. Then, each limestone was admixed with clay minerals to achieve the adequate chemical composition for clinker production. Raw meals were thermally threated at seven different temperatures, from 1000 to 1450 °C, to evaluate their behaviour on heating by ex situ X-Ray Powder Diffraction and to observe the final clinker morphology by Scanning Electron Microscopy. Results indicate the calcite microstrain is a reliable parameter to predict the burnability of the raw meals, in terms of calcium silicates growth and lime consumption. In particular, mixtures prepared starting from high-strained calcite exhibit a better burnability. Later, when the melt appears this correlation vanishes; however differences in the early burnability still reflect on the final clinker composition and texture.

Amorphous Phase Characterization Through X-Ray Diffraction Profile Modeling: Implications for Amorphous Phases in Gale Crater Rocks and Soils

NASA Technical Reports Server (NTRS)

Achilles, C. N.; Downs, G. W.; Downs, R. T.; Morris, R. V.; Rampe, E. B.; Ming, D. W.; Chipera, S. J.; Blake, D. F.; Vaniman, D. T.; Bristow, T. F.;

Farbrication of diffractive optical elements on a Si chip by an imprint lithography using nonsymmetrical silicon mold

NASA Astrophysics Data System (ADS)

Hirai, Yoshihiko; Okano, Masato; Okuno, Takayuki; Toyota, Hiroshi; Yotsuya, Tsutomu; Kikuta, Hisao; Tanaka, Yoshio

2001-11-01

Fabrication of a fine diffractive optical element on a Si chip is demonstrated using imprint lithography. A chirped diffraction grating, which has modulated pitched pattern with curved cross section is fabricated by an electron beam lithography, where the exposure dose profile is automatically optimized by computer aided system. Using the resist pattern as an etching mask, anisotropic dry etching is performed to transfer the resist pattern profile to the Si chip. The etched Si substrate is used as a mold in the imprint lithography. The Si mold is pressed to a thin polymer (poly methyl methacrylate) on a Si chip. After releasing the mold, a fine diffractive optical pattern is successfully transferred to the thin polymer. This method is exceedingly useful for fabrication of integrated diffractive optical elements with electric circuits on a Si chip.

The crystalline phases present in carbon cathodes of discharged Li/SOCl/sub 2/-LiAlCl/sub 4/ cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, R.M.; Surampudi, S.; Bankston, C.P.

1989-05-01

The authors describe the x-ray diffraction patterns of 100% discharged Schawinigan black cathodes from Li/SOCl/sub 2-/LiAlCl/sub 4/ cells obtained using a high resolution Guinier camera. The previous assignments of the diffraction lines to Li/sub 2/O/sub 2/ and rhombohedral sulfur are all found to be incorrect; all sharp Bragg diffraction lines not assignable to anhydrous LiCl can be assigned to LiCl1 . H/sub 2/O.

Diffraction and Imaging Study of Imperfections of Protein Crystals with Coherent X-rays

NASA Technical Reports Server (NTRS)

Hu, Z. W.; Thomas, B. R.; Chernov, A. A.; Chu, Y. S.; Lai, B.

2004-01-01

High angular-resolution x-ray diffraction and phase contrast x-ray imaging were combined to study defects and perfection of protein crystals. Imperfections including line defects, inclusions and other microdefects were observed in the diffraction images of a uniformly grown lysozyme crystal. The observed line defects carry distinct dislocation features running approximately along the <110> growth front and have been found to originate mostly in a central growth area and occasionally in outer growth regions. Slow dehydration led to the broadening of a fairly symmetric 4 4 0 rocking curve by a factor of approximately 2.6, which was primarily attributed to the dehydration-induced microscopic effects that are clearly shown in diffraction images. X-ray imaging and diffraction characterization of the quality of apoferritin crystals will also be discussed in the presentation.

Table of interplanar spacings for crystal-structure determinations by X-ray diffraction with molybdenum, copper, cobalt, iron, and chromium radiations

NASA Technical Reports Server (NTRS)

Kittel, J Howard

1945-01-01

For a simple diffraction pattern, the time required to calculate interplanar distances from measurements of the pattern is not excessive. If more than a few lines are present, however, or if several patterns are to be studied, it is very advantageous to have available a table giving interplanar spacings directly in terms of the linear measurements made on the film of the lines appearing on the diffraction pattern. The preparation of the table given here was undertaken when the expansion of research activities involving X-ray diffraction techniques indicated that such a table would greatly decrease the time required to analyze diffraction patterns. The table was prepared for use with K alpha(sub 1) radiation from the following target materials: molybdenum, copper, cobalt, iron, and chromium.

Lateral Downflows in Sunspot Penumbral Filaments and their Temporal Evolution

NASA Astrophysics Data System (ADS)

Esteban Pozuelo, S.; Bellot Rubio, L. R.; de la Cruz Rodríguez, J.

2015-04-01

We study the temporal evolution of downflows observed at the lateral edges of penumbral filaments in a sunspot located very close to the disk center. Our analysis is based on a sequence of nearly diffraction-limited scans of the Fe i 617.3 nm line taken with the CRisp Imaging Spectro-Polarimeter instrument at the Swedish 1 m Solar Telescope. We compute Dopplergrams from the observed intensity profiles using line bisectors and filter the resulting velocity maps for subsonic oscillations. Lateral downflows appear everywhere in the center-side penumbra as small, weak patches of redshifts next to or along the edges of blueshifted flow channels. These patches have an intermittent life and undergo mergings and fragmentations quite frequently. The lateral downflows move together with the hosting filaments and react to their shape variations, very much resembling the evolution of granular convection in the quiet Sun. There is a good relation between brightness and velocity in the center-side penumbra, with downflows being darker than upflows on average, which is again reminiscent of quiet Sun convection. These results point to the existence of overturning convection in sunspot penumbrae, with elongated cells forming filaments where the flow is upward but very inclined, and weak lateral downward flows. In general, the circular polarization profiles emerging from the lateral downflows do not show sign reversals, although sometimes we detect three-lobed profiles that are suggestive of opposite magnetic polarities in the pixel.

Models for Amorphous Calcium Carbonate

NASA Astrophysics Data System (ADS)

Sinha, Sourabh

Many species e.g. sea urchin form amorphous calcium carbonate (ACC) precursor phases that subsequently transform into crystalline CaCO3. It is certainly possible that the biogenic ACC might have more than 10 wt% Mg and ˜3 wt% of water. The structure of ACC and the mechanisms by which it transforms to crystalline phase are still poorly understood. In this dissertation our goal is to determine an atomic structure model that is consistent with diffraction and IR measurements of ACC. For this purpose a calcite supercell with 24 formula units, containing 120 atoms, was constructed. Various configurations with substitution of Ca by 6 Mg ions (6 wt.%) and insertion of 3-5 H 2O molecules (2.25-3.75 wt.%) in the interstitial positions of the supercell, were relaxed using a robust density function code VASP. The most noticeable effects were the tilts of CO3 groups and the distortion of Ca sub-lattice, especially in the hydrated case. The distributions of Ca-Ca nearest neighbor distance and CO3 tilts were extracted from various configurations. The same methods were also applied to aragonite. Sampling from the calculated distortion distributions, we built models for amorphous calcite/aragonite of size ˜ 1700 nm3 based on a multi-scale modeling scheme. We used these models to generate diffraction patterns and profiles with our diffraction code. We found that the induced distortions were not enough to generate a diffraction profile typical of an amorphous material. We then studied the diffraction profiles from several nano-crystallites as recent studies suggest that ACC might be a random array of nano-cryatallites. It was found that the generated diffraction profile from a nano-crystallite of size ˜ 2 nm3 is similar to that from the ACC.

THE CHARACTERIZATION OF A SOLID SORBENT WITH CRYSTALLITE SIZE AND STRAIN DATA FROM X-RAY DIFFRACTION LINE BROADENING

EPA Science Inventory

The paper gives results of the characterization of a solid sorbent with crystallite size and strain data from x-ray diffraction line broadening, as part of an EPA investigation of the injection of dry Ca(OH)2 into coal-fired electric power plant burners for the control of SO2 emi...

Devices useful for vacuum ultraviolet beam characterization including a movable stage with a transmission grating and image detector

DOEpatents

Gessner, Oliver; Kornilov, Oleg A; Wilcox, Russell B

2013-10-29

The invention provides for a device comprising an apparatus comprising (a) a transmission grating capable of diffracting a photon beam into a diffracted photon output, and (b) an image detector capable of detecting the diffracted photon output. The device is useful for measuring the spatial profile and diffraction pattern of a photon beam, such as a vacuum ultraviolet (VUV) beam.

The problem of scattering in fibre-fed VPH spectrographs and possible solutions

NASA Astrophysics Data System (ADS)

Ellis, S. C.; Saunders, Will; Betters, Chris; Croom, Scott

2014-07-01

All spectrographs unavoidably scatter light. Scattering in the spectral direction is problematic for sky subtraction, since atmospheric spectral lines are blurred. Scattering in the spatial direction is problematic for fibre fed spectrographs, since it limits how closely fibres can be packed together. We investigate the nature of this scattering and show that the scattering wings have both a Lorentzian component, and a shallower (1/r) component. We investigate the causes of this from a theoretical perspective, and argue that for the spectral PSF the Lorentzian wings are in part due to the profile of the illumination of the pupil of the spectrograph onto the diffraction grating, whereas the shallower component is from bulk scattering. We then investigate ways to mitigate the diffractive scattering by apodising the pupil. In the ideal case of a Gaussian apodised pupil, the scattering can be significantly improved. Finally we look at realistic models of the spectrograph pupils of fibre fed spectrographs with a centrally obstructed telescope, and show that it is possible to apodise the pupil through non-telecentric injection into the fibre.

Structural Mineral Physics at Extreme Conditions

NASA Astrophysics Data System (ADS)

Chariton, S.; Dubrovinsky, L. S.; Dubrovinskaia, N.

2017-12-01

Laser heating techniques in diamond anvil cells (DACs) cover a wide pressure-temperature range - above 300 GPa and up to 5000 K. Recent advantages in on-line laser heating techniques resulted in a significant improvement of reliability of in situ X-ray powder diffraction studies in laser-heated DACs, which have become routine at a number of synchrotron facilities including specialized beam-lines at the 3rd generation synchrotrons. However, until recently, existing DAC laser-heating systems could not be used for structural X-ray diffraction studies aimed at structural refinements, i.e. measuring of the diffraction intensities, and not only at determining of lattice parameters. The reason is that in existing DAC laser-heating facilities the laser beam enters the cell at a fixed angle, and a partial rotation of the DAC, as required in monochromatic structural X-ray diffraction experiments, results in a loss of the target crystal and may be even dangerous if the powerful laser light starts to scatter in arbitrary directions by the diamond anvils. In order to overcome this problem we have develop a portable laser heating system and implement it at different diffraction beam lines. We demonstrate the application of this system for simultaneous high-pressure and high-temperature powder and single crystal diffraction studies using examples of studies of chemical and phase relations in the Fe-O system, transition metals carbonates, and silicate perovskites.

An In-situ method for the study of strain broadening usingsynchrotronx-ray diffraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tang, Chiu C.; Lynch, Peter A.; Cheary, Robert W.

2006-12-15

A tensonometer for stretching metal foils has beenconstructed for the study of strain broadening in x-ray diffraction lineprofiles. This device, which is designed for use on the powderdiffractometer in Station 2.3 at Daresbury Laboratory, allows in-situmeasurements to be performed on samples under stress. It can be used fordata collection in either transmission or reflection modes using eithersymmetric or asymmetric diffraction geometries. As a test case,measurements were carried out on a 18mum thick copper foil experiencingstrain levels of up to 5 percent using both symmetric reflection andsymmetric transmission diffraction. All the diffraction profilesdisplayed peak broadening and asymmetry which increased with strain.more » Themeasured profiles were analysed by the fundamental parameters approachusing the TOPAS peak fitting software. All the observed broadenedprofiles were modelled by convoluting a refineable diffraction profile,representing the dislocation and crystallite size broadening, with afixed instrumental profile pre-determined usinghigh quality LaB6reference powder. The de-convolution process yielded "pure" sampleintegral breadths and asymmetry results which displayed a strongdependence on applied strain and increased almost linearly with appliedstrain. Assuming crystallite size broadening in combination withdislocation broadening arising from fcc a/2<110>111 dislocations,we have extracted the variation of mechanic al property with strain. Theobservation of both peak asymmetry and broadening has been interpreted asa manifestation of a cellular structure with cell walls and cellinteriors possessing high and low dislocation densities.« less

Field-induced antiferroelectric to ferroelectric transitions in (Pb 1–xLa x)(Zr 0.90Ti 0.10) 1–x/ 4O 3 investigated by in situ X-ray diffraction

DOE PAGES

Ciuchi, Ioana V.; Chung, Ching -Chang; Fancher, Christopher M.; ...

2017-06-17

Phase transitions and field-induced preferred orientation in (Pb 1-xLa x)(Zr 0.90Ti 0.10) 1–x/ 4O 3 (PLZT x/90/10) ceramics upon electric field cycling using in situ X-ray diffraction were studied. The evolution of the {200} pc and {111} pc diffraction line profiles indicate that PLZT 4/90/10 and PLZT 3/90/10 compositions undergo an antiferroelectric (AFE)–ferroelectric (FE) phase switching. Both PLZT 4/90/10 and PLZT 3/90/10 exhibit irreversible preferred orientation after experiencing the field-induced AFE-to-FE phase switching. An electric field-induced structure develops in both compositions which has a reversible character during the field decreasing in PLZT 4/90/10 and an irreversible character in PLZT 3/90/10.more » In addition, structural analysis of pre-poled PLZT 3/90/10 ceramics show that it is possible to induce consecutive FE-to-AFE and AFE-to-FE transitions when fields of reversed polarity are applied in sequence. The field range required to induce the AFE phase is broad, and the phase transition is kinetically slow. In conclusion, this kind of transition has rarely been reported before.« less

Field-induced antiferroelectric to ferroelectric transitions in (Pb 1–xLa x)(Zr 0.90Ti 0.10) 1–x/ 4O 3 investigated by in situ X-ray diffraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ciuchi, Ioana V.; Chung, Ching -Chang; Fancher, Christopher M.

Phase transitions and field-induced preferred orientation in (Pb 1-xLa x)(Zr 0.90Ti 0.10) 1–x/ 4O 3 (PLZT x/90/10) ceramics upon electric field cycling using in situ X-ray diffraction were studied. The evolution of the {200} pc and {111} pc diffraction line profiles indicate that PLZT 4/90/10 and PLZT 3/90/10 compositions undergo an antiferroelectric (AFE)–ferroelectric (FE) phase switching. Both PLZT 4/90/10 and PLZT 3/90/10 exhibit irreversible preferred orientation after experiencing the field-induced AFE-to-FE phase switching. An electric field-induced structure develops in both compositions which has a reversible character during the field decreasing in PLZT 4/90/10 and an irreversible character in PLZT 3/90/10.more » In addition, structural analysis of pre-poled PLZT 3/90/10 ceramics show that it is possible to induce consecutive FE-to-AFE and AFE-to-FE transitions when fields of reversed polarity are applied in sequence. The field range required to induce the AFE phase is broad, and the phase transition is kinetically slow. In conclusion, this kind of transition has rarely been reported before.« less

Multilayer diffraction at 104 keV

NASA Technical Reports Server (NTRS)

Krieger, Allen S.; Blake, Richard L.; Siddons, D. P.

1993-01-01

We have measured the diffraction peak of a W:Si synthetic multilayer reflector at 104 keV using the High Energy Bonse-Hart Camera at the X-17B hard X-ray wiggler beam line of the National Synchrotron Light Source at Brookhaven National Laboratory. The characteristics of the diffraction peak are described and compared to theory.

White-Light Diffraction with a CD

ERIC Educational Resources Information Center

Ivanov, Dragia Trifonov; Nikolaev, Stefan

2010-01-01

Various wave optics experiments can be carried out using an ordinary compact disc. The CD is suitable for use as a diffraction grating. For instance, a standard CD (700 MB) has 625 lines/mm. In this article, the authors describe two white-light diffraction demonstrations for a large audience, realizable using a CD (as reflection or transmission…

Electromagnetic diffraction radiation of a subwavelength-hole array excited by an electron beam.

PubMed

Liu, Shenggang; Hu, Min; Zhang, Yaxin; Li, Yuebao; Zhong, Renbin

2009-09-01

This paper explores the physics of the electromagnetic diffraction radiation of a subwavelength holes array excited by a set of evanescent waves generated by a line charge of electron beam moving parallel to the array. Activated by a uniformly moving line charge, numerous physical phenomena occur such as the diffraction radiation on both sides of the array as well as the electromagnetic penetration or transmission below or above the cut-off through the holes. As a result the subwavelength holes array becomes a radiation array. Making use of the integral equation with relevant Green's functions, an analytical theory for such a radiation system is built up. The results of the numerical calculations based on the theory agree well with that obtained by the computer simulation. The relation among the effective surface plasmon wave, the electromagnetic penetration or transmission of the holes and the diffraction radiation is revealed. The energy dependence of and the influence of the hole thickness on the diffraction radiation and the electromagnetic penetration or transmission are investigated in detail. Therefore, a distinct diffraction radiation phenomenon is discovered.

Precipitation-Induced Changes in Microstrain and Its Relation with Hardness and Tempering Parameter in 17-4 PH Stainless Steel

NASA Astrophysics Data System (ADS)

Mahadevan, S.; Manojkumar, R.; Jayakumar, T.; Das, C. R.; Rao, B. P. C.

2016-06-01

17-4 PH (precipitation hardening) stainless steel is a soft martensitic stainless steel strengthened by aging at appropriate temperature for sufficient duration. Precipitation of copper particles in the martensitic matrix during aging causes coherency strains which improves the mechanical properties, namely hardness and strength of the matrix. The contributions to X-ray diffraction (XRD) profile broadening due to coherency strains caused by precipitation and crystallite size changes due to aging are separated and quantified using the modified Williamson-Hall approach. The estimated normalized mean square strain and crystallite size are used to explain the observed changes in hardness. Microstructural changes observed in secondary electron images are in qualitative agreement with crystallite size changes estimated from XRD profile analysis. The precipitation kinetics in the age-hardening regime and overaged regime are studied from hardness changes and they follow the Avrami kinetics and Wilson's model, respectively. In overaged condition, the hardness changes are linearly correlated to the tempering parameter (also known as Larson-Miller parameter). Similar linear variation is observed between the normalized mean square strain (determined from XRD line profile analysis) and the tempering parameter, in the incoherent regime which is beyond peak microstrain conditions.

Diffractive variable beam splitter: optimal design.

PubMed

Borghi, R; Cincotti, G; Santarsiero, M

2000-01-01

The analytical expression of the phase profile of the optimum diffractive beam splitter with an arbitrary power ratio between the two output beams is derived. The phase function is obtained by an analytical optimization procedure such that the diffraction efficiency of the resulting optical element is the highest for an actual device. Comparisons are presented with the efficiency of a diffractive beam splitter specified by a sawtooth phase function and with the pertinent theoretical upper bound for this type of element.

Structure and mechanical behavior of heavily drawn pearlite and martensite in a high carbon steel

NASA Astrophysics Data System (ADS)

Shiota, Y.; Tomota, Y.; Moriai, A.; Kamiyama, T.

2005-10-01

Neutron diffraction measurements have revealed that cementite peaks disappear in a pearlite steel with drawing and that the residual intergranular stresses are generated. The diffraction profiles in a heavily drawn specimen suggest the tetoragonality with a small c/a in the ferrite matrix. Although cementite was hardly observed in the heavily drawn specimen, its c/a value determined by neutron diffraction and mechanical behavior are quite different from those of as-quenched martensite. The changes in hardness and c/a with annealing or tempering were also different between heavily drawn pearlite and marteniste. Hence, most of carbon atoms do not exist inside the ferrite lattice in the drawn pearlite and multi-scaled heterogeneous plastic deformation in pearlite seems to affect the asymmetry in the diffraction profile. Fracture behavior and hardness change with tempering is different in the two microstructures.

Sucrose lyophiles: a semi-quantitative study of residual water content by total X-ray diffraction analysis.

PubMed

Bates, S; Jonaitis, D; Nail, S

2013-10-01

Total X-ray Powder Diffraction Analysis (TXRPD) using transmission geometry was able to observe significant variance in measured powder patterns for sucrose lyophilizates with differing residual water contents. Integrated diffraction intensity corresponding to the observed variances was found to be linearly correlated to residual water content as measured by an independent technique. The observed variance was concentrated in two distinct regions of the lyophilizate powder pattern, corresponding to the characteristic sucrose matrix double halo and the high angle diffuse region normally associated with free-water. Full pattern fitting of the lyophilizate powder patterns suggested that the high angle variance was better described by the characteristic diffraction profile of a concentrated sucrose/water system rather than by the free-water diffraction profile. This suggests that the residual water in the sucrose lyophilizates is intimately mixed at the molecular level with sucrose molecules forming a liquid/solid solution. The bound nature of the residual water and its impact on the sucrose matrix gives an enhanced diffraction response between 3.0 and 3.5 beyond that expected for free-water. The enhanced diffraction response allows semi-quantitative analysis of residual water contents within the studied sucrose lyophilizates to levels below 1% by weight. Copyright © 2013 Elsevier B.V. All rights reserved.

Spectral diffraction efficiency characterization of broadband diffractive optical elements.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Choi, Junoh; Cruz-Cabrera, Alvaro Augusto; Tanbakuchi, Anthony

Diffractive optical elements, with their thin profile and unique dispersion properties, have been studied and utilized in a number of optical systems, often yielding smaller and lighter systems. Despite the interest in and study of diffractive elements, the application has been limited to narrow spectral bands. This is due to the etch depths, which are optimized for optical path differences of only a single wavelength, consequently leading to rapid decline in efficiency as the working wavelength shifts away from the design wavelength. Various broadband diffractive design methodologies have recently been developed that improve spectral diffraction efficiency and expand the workingmore » bandwidth of diffractive elements. We have developed diffraction efficiency models and utilized the models to design, fabricate, and test two such extended bandwidth diffractive designs.« less

Quick measurement of crystal truncation rod profiles in simultaneous multi-wavelength dispersive mode

NASA Astrophysics Data System (ADS)

Matsushita, T.; Takahashi, T.; Shirasawa, T.; Arakawa, E.; Toyokawa, H.; Tajiri, H.

2011-11-01

To conduct time-resolved measurements in the wide momentum transfer (q = 4π sinθ/λ, θ: the glancing angle of the x-ray beam, λ: x-ray wavelength) range of interest, we developed a method that can simultaneously measure the whole profile of x-ray diffraction and crystal truncation rod scattering of interest with no need of rotation of the specimen, detector, and monochromator crystal during the measurement. With a curved crystal polychromator (Si 111 diffraction), a horizontally convergent x-ray beam having a one-to-one correlation between wavelength (energy: 16.24-23.0 keV) and direction is produced. The convergent x-ray beam components of different wavelengths are incident on the specimen in a geometry where θ is the same for all the x-ray components and are diffracted within corresponding vertical scattering planes by a specimen ([GaAs(12ML)/AlAs(8 ML)]50 on GaAs(001) substrate) placed at the focal point. Although θ is the same for all the directions, q continuously varies because λ changes as a function of direction. The normalized horizontal intensity distribution across the beam, as measured using a two-dimensional pixel array detector downstream of the specimen, represents the reflectivity curve profile both near to and far from the Bragg point. As for the crystal truncation rod scattering around the 002 reflection, the diffraction profile from the Bragg peak down to reflectivity of 1.0 × 10-9 was measured with a sufficient data collection time (1000-2000 s). With data collection times of 100, 10, 1.0, and 0.1 s, profiles down to a reflectivity of ˜6 × 10-9, ˜2 × 10-8, ˜8 × 10-8, and ˜8 × 10-7 were measured, respectively. To demonstrate the time-resolving capability of the system, reflectivity curves were measured with time resolutions of 1.0 s while rotating the specimen. We have also measured the diffraction profile around the 113 reflection in the non-specular reflection geometry.

Diffractive Alvarez lens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barton, Ian M.; Dixit, Sham N.; Summers, Leslie J.

2000-01-01

A diffractive Alvarez lens is demonstrated that consists of two separate phase plates, each having complementary 16-level surface-relief profiles that contain cubic phase delays. Translation of these two components in the plane of the phase plates is shown to produce a variable astigmatic focus. Both spherical and cylindrical phase profiles are demonstrated with good accuracy, and the discrete surface-relief features are shown to cause less than {lambda}/10 wave-front aberration in the transmitted wave front over a 40 mmx80 mm region. (c) 2000 Optical Society of America.

New test of the dynamic theory of neutron diffraction by a moving grating

NASA Astrophysics Data System (ADS)

Zakharov, Maxim; Frank, Alexander; Kulin, German; Goryunov, Semyon

2018-04-01

Recently, multiwave dynamical theory of neutron diffraction by a moving grating was developed. The theory predicts that at a certain height of the grating profile a significant suppression of the zero-order diffraction may occur. The experiment to confirm predictions of this theory was performed. The resulting diffracted UCNs spectra were measured using time-of-flight Fourier diffractometer. The experimental data were compared with the results of numerical simulation and were found in a good agreement with theoretical predictions.

Diffractive shear interferometry for extreme ultraviolet high-resolution lensless imaging

NASA Astrophysics Data System (ADS)

Jansen, G. S. M.; de Beurs, A.; Liu, X.; Eikema, K. S. E.; Witte, S.

2018-05-01

We demonstrate a novel imaging approach and associated reconstruction algorithm for far-field coherent diffractive imaging, based on the measurement of a pair of laterally sheared diffraction patterns. The differential phase profile retrieved from such a measurement leads to improved reconstruction accuracy, increased robustness against noise, and faster convergence compared to traditional coherent diffractive imaging methods. We measure laterally sheared diffraction patterns using Fourier-transform spectroscopy with two phase-locked pulse pairs from a high harmonic source. Using this approach, we demonstrate spectrally resolved imaging at extreme ultraviolet wavelengths between 28 and 35 nm.

Luminescent properties under X-ray excitation of Ba(1-x)PbxWO4 disordered solid solution

NASA Astrophysics Data System (ADS)

Bakiz, B.; Hallaoui, A.; Taoufyq, A.; Benlhachemi, A.; Guinneton, F.; Villain, S.; Ezahri, M.; Valmalette, J.-C.; Arab, M.; Gavarri, J.-R.

2018-02-01

A series of polycrystalline barium-lead tungstate Ba1-xPbxWO4 with 0 ≤ x ≤ 1 was synthesized using a classical solid-state method with thermal treatment at 1000 °C. These materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Raman (FT-Raman) spectroscopy. X-ray diffraction profile analyses were performed using Rietveld method. These materials crystallized in the scheelite tetragonal structure and behaved as quasi ideal solid solution. Raman spectroscopy confirmed the formation of the solid solution. Structural distortions were evidenced in X-ray diffraction profiles and in vibration Raman spectra. The scanning electron microscopy experiments showed large and rounded irregular grains. Luminescence experiments were performed under X-ray excitation. The luminescence emission profiles have been interpreted in terms of four Gaussian components, with a major contribution of blue emission. The integrated intensity of luminescence reached a maximum value in the composition range x = 0.3-0.6, in relation with distortions of crystal lattice.

Blazed vector gratings fabricated using photosensitive polymer liquid crystals and control of polarization diffraction

NASA Astrophysics Data System (ADS)

Ono, Hiroshi; Kuzuwata, Mitsuru; Sasaki, Tomoyuki; Noda, Kohei; Kawatsuki, Nobuhiro

2014-03-01

The blazed vector grating possessing antisymmetric distributions of the birefringence were fabricated by exposing the line-focused linearly polarized ultraviolet light on the photosensitive polymer liquid crystals. The polarization states of the diffraction beams can be highly and widely controlled by designing the blazed structures, and the diffraction properties were well-explained by Jones calculus.

Finite element area and line integral transforms for generalization of aperture function and geometry in Kirchhoff scalar diffraction theory

NASA Astrophysics Data System (ADS)

Kraus, Hal G.

1993-02-01

Two finite element-based methods for calculating Fresnel region and near-field region intensities resulting from diffraction of light by two-dimensional apertures are presented. The first is derived using the Kirchhoff area diffraction integral and the second is derived using a displaced vector potential to achieve a line integral transformation. The specific form of each of these formulations is presented for incident spherical waves and for Gaussian laser beams. The geometry of the two-dimensional diffracting aperture(s) is based on biquadratic isoparametric elements, which are used to define apertures of complex geometry. These elements are also used to build complex amplitude and phase functions across the aperture(s), which may be of continuous or discontinuous form. The finite element transform integrals are accurately and efficiently integrated numerically using Gaussian quadrature. The power of these methods is illustrated in several examples which include secondary obstructions, secondary spider supports, multiple mirror arrays, synthetic aperture arrays, apertures covered by screens, apodization, phase plates, and off-axis apertures. Typically, the finite element line integral transform results in significant gains in computational efficiency over the finite element Kirchhoff transform method, but is also subject to some loss in generality.

Capability of X-ray diffraction for the study of microstructure of metastable thin films

PubMed Central

Rafaja, David; Wüstefeld, Christina; Dopita, Milan; Motylenko, Mykhaylo; Baehtz, Carsten

2014-01-01

Metastable phases are often used to design materials with outstanding properties, which cannot be achieved with thermodynamically stable compounds. In many cases, the metastable phases are employed as precursors for controlled formation of nanocomposites. This contribution shows how the microstructure of crystalline metastable phases and the formation of nanocomposites can be concluded from X-ray diffraction experiments by taking advantage of the high sensitivity of X-ray diffraction to macroscopic and microscopic lattice deformations and to the dependence of the lattice deformations on the crystallographic direction. The lattice deformations were determined from the positions and from the widths of the diffraction lines, the dependence of the lattice deformations on the crystallographic direction from the anisotropy of the line shift and the line broadening. As an example of the metastable system, the supersaturated solid solution of titanium nitride and aluminium nitride was investigated, which was prepared in the form of thin films by using cathodic arc evaporation of titanium and aluminium in a nitrogen atmosphere. The microstructure of the (Ti,Al)N samples under study was tailored by modifying the [Al]/[Ti] ratio in the thin films and the surface mobility of the deposited species. PMID:25485125

A new method for the identification of non-Gaussian line profiles in elliptical galaxies

NASA Technical Reports Server (NTRS)

Van Der Marel, Roeland P.; Franx, Marijn

1993-01-01

A new parameterization for the line profiles of elliptical galaxies, the Gauss-Hermite series, is proposed. This approach expands the line profile as a sum of orthogonal functions which minimizes the correlations between the errors in the parameters of the fit. This method also make use of the fact that Gaussians provide good low-order fits to observed line profiles. The method yields measurements of the line strength, mean radial velocity, and the velocity dispersion as well as two extra parameters, h3 and h4, that measure asymmetric and symmetric deviations of the line profiles from a Gaussian, respectively. The new method was used to derive profiles for three elliptical galaxies which all have asymmetric line profiles on the major axis with symmetric deviations from a Gaussian. Results confirm that elliptical galaxies have complex structures due to their complex formation history.

Investigation on surface layer characteristics of shot peened graphene reinforced Al composite by X-ray diffraction method

NASA Astrophysics Data System (ADS)

Zhan, Ke; Wu, Yihao; Li, Jiongli; Zhao, Bin; Yan, Ya; Xie, Lechun; Wang, Lianbo; Ji, V.

2018-03-01

Graphene reinforced Al composite with high mechanical property was successfully reported. However, there are quite limited studies about shot peening effect on this new type material. Here, 1.0 wt% graphene reinforced Al composite was produced by powder metallurgy and treated by shot peening. The surface layer characteristics of shot peened composite was investigated by X-ray diffraction line profile analysis. The microstructure including domain size, micro-strain, dislocation density and crystalline texture were analyzed. The results showed that after surface shot-peening, the domain size were refined, the dislocation density of the composite was increased sharply to 9.0 × 1011/cm2 at the top surface. The original strong texture was diminished after shot peening. Based on the calculated results, the microstructure variation of composite was more severe than that of Al without graphene reinforcement after shot peening. Besides, the micro-hardness of composite at the top surface increased up to 75HV one time higher than that of matrix. It is concluded that shot peening can be considered as an essential process of improving the surface properties of graphene reinforced Al composite.

Measurement of 3D refractive index distribution by optical diffraction tomography

NASA Astrophysics Data System (ADS)

Chi, Weining; Wang, Dayong; Wang, Yunxin; Zhao, Jie; Rong, Lu; Yuan, Yuanyuan

2018-01-01

Optical Diffraction Tomography (ODT), as a novel 3D imaging technique, can obtain a 3D refractive index (RI) distribution to reveal the important optical properties of transparent samples. According to the theory of ODT, an optical diffraction tomography setup is built based on the Mach-Zehnder interferometer. The propagation direction of object beam is controlled by a 2D translation stage, and 121 holograms based on different illumination angles are recorded by a Charge-coupled Device (CCD). In order to prove the validity and accuracy of the ODT, the 3D RI profile of microsphere with a known RI is firstly measured. An iterative constraint algorithm is employed to improve the imaging accuracy effectively. The 3D morphology and average RI of the microsphere are consistent with that of the actual situation, and the RI error is less than 0.0033. Then, an optical element fabricated by laser with a non-uniform RI is taken as the sample. Its 3D RI profile is obtained by the optical diffraction tomography system.

X-ray diffraction patterns and diffracted intensity of Kα spectral lines of He-like ions

NASA Astrophysics Data System (ADS)

Goyal, Arun; Khatri, Indu; Singh, A. K.; Sharma, Rinku; Mohan, Man

2017-09-01

In the present paper, we have calculated fine-structure energy levels related to the configurations 1s2s, 1s2p, 1s3s and 1s3p by employing GRASP2K code. We have also computed radiative data for transitions from 1s2p 1 P1o, 1s2p 3 P2o, 1s2p 3 P1o and 1s2s 3S1 to the ground state 1s2. We have made comparisons of our presented energy levels and transition wavelengths with available results compiled by NIST and good agreement is achieved. We have also provided X-ray diffraction (XRD) patterns of Kα spectral lines, namely w, x, y and z of Cu XXVIII, Kr XXXV and Mo with diffraction angle and maximum diffracted intensity which is not published elsewhere in the literature. We believe that our presented results may be beneficial in determination of the order parameter, X-ray crystallography, solid-state drug analysis, forensic science, geological and medical applications.

A Bayesian approach to modeling diffraction profiles and application to ferroelectric materials

DOE PAGES

Iamsasri, Thanakorn; Guerrier, Jonathon; Esteves, Giovanni; ...

2017-02-01

A new statistical approach for modeling diffraction profiles is introduced, using Bayesian inference and a Markov chain Monte Carlo (MCMC) algorithm. This method is demonstrated by modeling the degenerate reflections during application of an electric field to two different ferroelectric materials: thin-film lead zirconate titanate (PZT) of composition PbZr 0.3Ti 0.7O 3and a bulk commercial PZT polycrystalline ferroelectric. Here, the new method offers a unique uncertainty quantification of the model parameters that can be readily propagated into new calculated parameters.

High dynamic grayscale lithography with an LED-based micro-image stepper

NASA Astrophysics Data System (ADS)

Eckstein, Hans-Christoph; Zeitner, Uwe D.; Leitel, Robert; Stumpf, Marko; Schleicher, Philipp; Bräuer, Andreas; Tünnermann, Andreas

2016-03-01

We developed a novel LED projection based direct write grayscale lithography system for the generation of optical surface profiles such as micro-lenses, diffractive elements, diffusors, and micro freeforms. The image formation is realized by a LCoS micro-display which is illuminated by a 405 nm UV High Power LED. The image on the display can be demagnified from factors 5x to 100x with an exchangeable lens. By controlling exposure time and LED power, the presented technique enables a highly dynamic dosage control for the exposure of h-line sensitive photo resist. In addition, the LCoS micro-display allows for an intensity control within the micro-image which is particularly advantageous to eliminate surface profile errors from stitching and limited homogeneity from LED illumination. Together with an accurate calibration of the resist response this leads to a superior low surface error of realized profiles below <0.2% RMS. The micro-display is mounted on a 3-axis (XYθ) stage for precise alignment. The substrate is brought into position with an air bearing stage which addresses an area of 500 × 500 mm2 with a positioning accuracy of <100 nm. As the exposure setup performs controlled motion in the z-direction the system to maintain the focal distance and lithographic patterning on non-planar surfaces to some extent. The exposure concept allows a high structure depth of more than 100 μm and a spatial resolution below 1 μm as well as the possibility of very steep sidewalls with angles larger than >80°. Another benefit of the approach is a patterning speed up to 100 cm2/h, which allows fabricating large-scale optics and microstructures in an acceptable time. We present the setup and show examples of micro-structures to demonstrate the performance of the system, namely a refractive freeform array, where the RMS surface deviation does not exceed 0.2% of the total structure depth of 75 μm. Furthermore, we show that this exposure tool is suitable to generate diffractive optical elements as well as freeform optics and arrays with a high aspect ratio and structure depth showing a superior optical performance. Lastly we demonstrate a multi-level diffraction grating on a curved substrate.

Evaluating cell lines as tumour models by comparison of genomic profiles

PubMed Central

Domcke, Silvia; Sinha, Rileen; Levine, Douglas A.; Sander, Chris; Schultz, Nikolaus

2013-01-01

Cancer cell lines are frequently used as in vitro tumour models. Recent molecular profiles of hundreds of cell lines from The Cancer Cell Line Encyclopedia and thousands of tumour samples from the Cancer Genome Atlas now allow a systematic genomic comparison of cell lines and tumours. Here we analyse a panel of 47 ovarian cancer cell lines and identify those that have the highest genetic similarity to ovarian tumours. Our comparison of copy-number changes, mutations and mRNA expression profiles reveals pronounced differences in molecular profiles between commonly used ovarian cancer cell lines and high-grade serous ovarian cancer tumour samples. We identify several rarely used cell lines that more closely resemble cognate tumour profiles than commonly used cell lines, and we propose these lines as the most suitable models of ovarian cancer. Our results indicate that the gap between cell lines and tumours can be bridged by genomically informed choices of cell line models for all tumour types. PMID:23839242

The tymbal muscle of cicada has flight muscle-type sarcomeric architecture and protein expression.

PubMed

Iwamoto, Hiroyuki

2017-01-01

The structural and biochemical features of the tymbal (sound-producing) muscle of cicadas were studied by X-ray diffraction and immunochemistry, and compared with those of flight muscles from the same species. The X-ray diffraction pattern of the tymbal muscle was very similar to that of the dorsal longitudinal flight muscle: In both muscles, the 2,0 equatorial reflection is much more intense than the 1,1, indicating that both muscles have a flight muscle-type myofilament lattice. In rigor, the first myosin/actin layer line reflection was finely lattice-sampled, indicating that the contractile proteins are arranged with a crystalline regularity as in asynchronous flight muscles. In contrast, the diffraction pattern from the tensor muscle, which modulates the sound by stressing the tymbal, did not show signs of such high regularity or flight muscle-type filament lattice. Electrophoretic patterns of myofibrillar proteins were also very similar in the tymbal muscle and flight muscles, but distinct from those from the tensor or leg muscles. The antibody raised against the flight muscle-specific troponin-I isoform reacted with an 80-kDa band from both tymbal and flight muscles, but with none of the bands from the tensor or leg muscles. The close similarities of the structural and biochemical profiles between the tymbal and the flight muscles suggest the possibility that a set of flight muscle-specific proteins is diverted to the tymbal muscle to meet its demand for fast, repetitive contractions.

In-line digital holography with phase-shifting Greek-ladder sieves

NASA Astrophysics Data System (ADS)

Xie, Jing; Zhang, Junyong; Zhang, Yanli; Zhou, Shenlei; Zhu, Jianqiang

2018-04-01

Phase shifting is the key technique in in-line digital holography, but traditional phase shifters have their own limitations in short wavelength regions. Here, phase-shifting Greek-ladder sieves with amplitude-only modulation are introduced into in-line digital holography, which are essentially a kind of diffraction lens with three-dimensional array diffraction-limited foci. In the in-line digital holographic experiment, we design two kinds of sieves by lithography and verify the validity of their phase-shifting function by measuring a 1951 U.S. Air Force resolution test target and three-dimensional array foci. With advantages of high resolving power, low cost, and no limitations at shorter wavelengths, phase-shifting Greek-ladder sieves have great potential in X-ray holography or biochemical microscopy for the next generation of synchrotron light sources.

Requirements and Technology Advances for Global Wind Measurement with a Coherent Lidar: A Shrinking Gap

NASA Technical Reports Server (NTRS)

Kavaya, Michael J.; Kavaya, Michael J.; Yu, Jirong; Koch, Grady J.; Amzajerdian, Farzin; Singh, Upendra N.; Emmitt, G. David

2007-01-01

Early concepts to globally measure vertical profiles of vector horizontal wind from space planned on an orbit height of 525 km, a single pulsed coherent Doppler lidar system to cover the full troposphere, and a continuously rotating telescope/scanner that mandated a vertical line of sight wind profile from each laser shot. Under these conditions system studies found that laser pulse energies of approximately 20 J at 10 Hz pulse repetition rate with a rotating telescope diameter of approximately 1.5 m was required. Further requirements to use solid state laser technology and an eyesafe wavelength led to the relatively new 2-micron solid state laser. With demonstrated pulse energies near 20 mJ at 5 Hz, and no demonstration of a rotating telescope maintaining diffraction limited performance in space, the technology gap between requirements and demonstration was formidable. Fortunately the involved scientists and engineers set out to reduce the gap, and through a combination of clever ideas and technology advances over the last 15 years, they have succeeded. This paper will detail the gap reducing factors and will present the current status.

Influence of 4,4’-azobis (4-cyanopentanoic acid) in Transmission and Reflection Gratings Stored in a PVA/AA Photopolymer

PubMed Central

Fernandez, Elena; Fuentes, Rosa; Belendez, Augusto; Pascual, Inmaculada

2016-01-01

Holographic transmission gratings with a spatial frequency of 2658 lines/mm and reflection gratings with a spatial frequency of 4553 lines/mm were stored in a polyvinyl alcohol (PVA)/acrylamide (AA) based photopolymer. This material can reach diffraction efficiencies close to 100% for spatial frequencies about 1000 lines/mm. However, for higher spatial frequencies, the diffraction efficiency decreases considerably as the spatial frequency increases. To enhance the material response at high spatial frequencies, a chain transfer agent, the 4,4’-azobis (4-cyanopentanoic acid), ACPA, is added to the composition of the material. Different concentrations of ACPA are incorporated into the main composition of the photopolymer to find the concentration value that provides the highest diffraction efficiency. Moreover, the refractive index modulation and the optical thickness of the transmission and reflection gratings were obtained, evaluated and compared to procure more information about the influence of the ACPA on them. PMID:28773322

Huygen-Fresnel Diffraction Model H-Fdm for the Simulation of Ultrasonic Time-Of Diffraction Technique in 2d Geometries

NASA Astrophysics Data System (ADS)

Reddy, K. Sanjeeva; Krishnamurthy, C. V.; Balasubramaniam, Krishnan; Balasubramanian, T.

2010-02-01

This paper discusses the evaluation of diffracted signals from cracks in 2D based on a new Huygen-Fresnel Diffraction Model (H-FDM). The model employs the frequency-domain far-field displacement expressions derived by Miller & Pursey [1] in 2D for a line source located on the free surface of a semi-infinite elastic medium. At each frequency in the bandwidth of a pulsed excitation, the complex diffracted field is obtained by summing over the unblocked virtual sources located in the section containing a vertical crack. The time-domain diffracted signal is obtained using standard FFT procedures. The effect of beam refraction from a wedge-based finite transducer has been modeled by treating the finite transducer as an array of line sources. The model has been used for predicting diffracted signals in time-of-flight from the crack like defect. The model allows the evaluation of back wall signal amplitude and lateral wave amplitude as well. Experiments have been carried out on 10 mm thick aluminum sample with surface breaking crack of lengths 2 mm and 4 mm using shear probe shoe. The simulated A-Scan results for the aluminum sample with 2 mm and 4 mm surface breaking lengths compare very well in relative amplitudes and time of arrivals with experiments. The H-FDM model offers a tool to evaluate diffraction and related phenomena quantitatively with modest computational resources.

La méthode des coordonnées curvilignes appliquée à la diffraction par des réseaux dont le profil est donné par des équations paramétriques: application à la diffraction par un réseau cycloïdal The method of curvilinear coordinates applied to the problem of scattering from surface-relief gratings defined by parametric equations: application to scattering from a cycloidal grating

NASA Astrophysics Data System (ADS)

Granet, Gérard; Chandezon, Jean

1997-11-01

The method of curvilinear coordinates is formulated using the coordinate transformations given by parametric equations. As an illustration, a translation coordinate system and a relaxation coordinate system are used to calculate the reflectivities of various cycloidal profiles. We show, with this example, that parametric coordinate systems permit one to handle profiles that previously had been out of reach owing to their sharpness.

Trapezoidal diffraction grating beam splitters in single crystal diamond

NASA Astrophysics Data System (ADS)

Kiss, Marcell; Graziosi, Teodoro; Quack, Niels

2018-02-01

Single Crystal Diamond has been recognized as a prime material for optical components in high power applications due to low absorption and high thermal conductivity. However, diamond microstructuring remains challenging. Here, we report on the fabrication and characterization of optical diffraction gratings exhibiting a symmetric trapezoidal profile etched into a single crystal diamond substrate. The optimized grating geometry diffracts the transmitted optical power into precisely defined proportions, performing as an effective beam splitter. We fabricate our gratings in commercially available single crystal CVD diamond plates (2.6mm x 2.6mm x 0.3mm). Using a sputter deposited hard mask and patterning by contact lithography, the diamond is etched in an inductively coupled oxygen plasma with zero platen power. The etch process effectively reveals the characteristic {111} diamond crystal planes, creating a precisely defined angled (54.7°) profile. SEM and AFM measurements of the fabricated gratings evidence the trapezoidal shape with a pitch of 3.82μm, depth of 170 nm and duty cycle of 35.5%. Optical characterization is performed in transmission using a 650nm laser source perpendicular to the sample. The recorded transmitted optical power as function of detector rotation angle shows a distribution of 21.1% in the 0th order and 23.6% in each +/-1st order (16.1% reflected, 16.6% in higher orders). To our knowledge, this is the first demonstration of diffraction gratings with trapezoidal profile in single crystal diamond. The fabrication process will enable beam splitter gratings of custom defined optical power distribution profiles, while antireflection coatings can increase the efficiency.

A Homing Missile Control System to Reduce the Effects of Radome Diffraction

NASA Technical Reports Server (NTRS)

Smith, Gerald L.

1960-01-01

The problem of radome diffraction in radar-controlled homing missiles at high speeds and high altitudes is considered from the point of view of developing a control system configuration which will alleviate the deleterious effects of the diffraction. It is shown that radome diffraction is in essence a kinematic feedback of body angular velocities which causes the radar to sense large apparent line-of-sight angular velocities. The normal control system cannot distinguish between the erroneous and actual line-of-sight rates, and entirely wrong maneuvers are produced which result in large miss distances. The problem is resolved by adding to the control system a special-purpose computer which utilizes measured body angular velocity to extract from the radar output true line-of-sight information for use in steering the missile. The computer operates on the principle of sampling and storing the radar output at instants when the body angular velocity is low and using this stored information for maneuvering commands. In addition, when the angular velocity is not low the computer determines a radome diffraction compensation which is subtracted from the radar output to reduce the error in the sampled information. Analog simulation results for the proposed control system operating in a coplanar (vertical plane) attack indicate a potential decrease in miss distance to an order of magnitude below that for a conventional system. Effects of glint noise, random target maneuvers, initial heading errors, and missile maneuverability are considered in the investigation.

Relations for lipid bilayers. Connection of electron density profiles to other structural quantities.

PubMed Central

Nagle, J F; Wiener, M C

1989-01-01

Three relations are derived that connect low angle diffraction/scattering results obtained from lipid bilayers to other structural quantities of interest. The first relates the area along the surface of the bilayer, the measured specific volume, and the zeroth order structure factor, F(0). The second relates the size of the trough in the center of the electron density profile, the volume of the terminal methyl groups, and the volume of the methylene groups in the fatty acid chains. The third relates the size of the headgroup electron density peak, the volume of the headgroup, and the volumes of water and hydrocarbon in the headgroup region. These relations, which are easily modified for neutron diffraction, are useful for obtaining structural quantities from electron density profiles obtained by fitting model profiles to measured low angle x-ray intensities. PMID:2713444

On the possibility of using polycrystalline material in the development of structure-based generic assays

DOE Office of Scientific and Technical Information (OSTI.GOV)

Allaire, Marc, E-mail: allaire@bnl.gov; Moiseeva, Natalia; Botez, Cristian E.

The correlation coefficients calculated between raw powder diffraction profiles can be used to identify ligand-bound/unbound states of lysozyme. The discovery of ligands that bind specifically to a targeted protein benefits from the development of generic assays for high-throughput screening of a library of chemicals. Protein powder diffraction (PPD) has been proposed as a potential method for use as a structure-based assay for high-throughput screening applications. Building on this effort, powder samples of bound/unbound states of soluble hen-egg white lysozyme precipitated with sodium chloride were compared. The correlation coefficients calculated between the raw diffraction profiles were consistent with the known bindingmore » properties of the ligands and suggested that the PPD approach can be used even prior to a full description using stereochemically restrained Rietveld refinement.« less

X-ray topography using the forward transmitted beam under multiple-beam diffraction conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsusaka, Y., E-mail: tsusaka@sci.u-hyogo.ac.jp; Takano, H.; Takeda, S.

2016-02-15

X-ray topographs are taken for a sapphire wafer with the [0001] surface normal, as an example, by forward transmitted synchrotron x-ray beams combined with two-dimensional electronic arrays in the x-ray detector having a spatial resolution of 1 μm. They exhibit no shape deformation and no position shift of the dislocation lines on the topographs. Since the topography is performed under multiple-beam diffraction conditions, the topographic images of a single diffraction (two-wave approximation condition) or plural diffractions (six-wave approximation condition) can be recorded without large specimen position changes. As usual Lang topographs, it is possible to determine the Burgers vector ofmore » each dislocation line. Because of high parallelism of the incoming x-rays and linear sensitivity of the electronic arrays to the incident x-rays, the present technique can be used to visualize individual dislocations in single crystals of the dislocation density as high as 1 × 10{sup 5} cm{sup −2}.« less

FFT Deconvultion of Be Star Hα Line Profiles

NASA Astrophysics Data System (ADS)

Austin, S. J.

2005-12-01

We have been monitoring the spectroscopic variability of Be stars using the UCA Fiber Fed Spectrograph. The spectra are 0.8 Angstrom/pixel resolution of the Hα line. The observed line profiles are a convolution of the actual profile and the instrumental profile. A Fast Fourier Transform (FFT) method has been used to deconvolve the observed profiles, given the instrument profile obtained by observing the narrow lines from the HgNe wavelength calibration lamp. The long-term monitoring of the spectroscopic variability of Be stars is crucial for testing the various Be star models. Deconvolved H-α line profiles, velocities, and variability are shown for gamma Cas, delta Sco, chi Oph, eta PsA, 48 Lib, and upsilon Sgr (HD181615). Funding has been provided by the UCA University Research Council and the Arkansas Space Grant Consortium.

IUE observations of Si and C lines and comparison with non-LTE models

NASA Technical Reports Server (NTRS)

Kamp, L. W.

1982-01-01

Classical model atmosphere techniques are applied to analyze IUE spectra, and to determine abundances, effective temperatures and gravities. Measurements of the equivalent widths and other properties of the line profiles of 24 photospheric lines of Si II, Si III, Si IV, C II, C III and C IV are presented in the range of 1175-1725 A for seven B and two O stars. Observed line profiles are compared with theoretical profiles computed using non-LTE theory and models, and using line-blanketed model atmospheres. Agreement is reasonably good, although strong lines are calculated to be systematically stronger than those observed, while the reverse occurs for weak lines, and empirical profiles have smaller wings than theoretical profiles. It is concluded that the present theory of line formation when used with solar abundances, represents fairly well observed UV photospheric lines of silicon and carbon ions in the atmospheres of main sequence stars of types B5-O9.

Diffraction as a Method of Critical Policy Analysis

ERIC Educational Resources Information Center

Ulmer, Jasmine B.

2016-01-01

Recent developments in critical policy analysis have occurred alongside the new materialisms in qualitative research. These lines of scholarship have unfolded along two separate, but related, tracks. In particular, the new materialist method of "diffraction" aligns with many elements of critical policy analysis. Both involve critical…

Line profiles and turbulence generated by acoustic waves in the solar chromosphere. II - Contours of the Ca II and Mg II K lines

NASA Technical Reports Server (NTRS)

Shine, R. A.; Oster, L.

1973-01-01

Making use of the time-averaged absorption profiles derived by Oster and Ulmschneider, non-LTE line formation in the context of a two-level atom is investigated for an isothermal atmosphere and for the Ca II and Mg II K lines in the solar chromosphere as represented by the Harvard-Smithsonian Reference Atmosphere. Source functions and emergent line profiles are computed for a variety of assumptions concerning the acoustically broadened profiles and the solar velocity fields.

Impact of oxygen diffusion on superconductivity in YBa2Cu3O7 -δ thin films studied by positron annihilation spectroscopy

NASA Astrophysics Data System (ADS)

Reiner, M.; Gigl, T.; Jany, R.; Hammerl, G.; Hugenschmidt, C.

2018-04-01

The oxygen deficiency δ in YBa2Cu3O7 -δ (YBCO) plays a crucial role for affecting high-temperature superconductivity. We apply (coincident) Doppler broadening spectroscopy of the electron-positron annihilation line to study in situ the temperature dependence of the oxygen concentration and its depth profile in single crystalline YBCO film grown on SrTiO3 (STO) substrates. The oxygen diffusion during tempering is found to lead to a distinct depth dependence of δ , which is not accessible using x-ray diffraction. A steady state reached within a few minutes is defined by both, the oxygen exchange at the surface and at the interface to the STO substrate. Moreover, we reveal the depth-dependent critical temperature Tc in the as prepared and tempered YBCO film.

Atomic Ferris wheel beams

NASA Astrophysics Data System (ADS)

Lembessis, Vasileios E.

2017-07-01

We study the generation of atom vortex beams in the case where a Bose-Einstein condensate, released from a trap and moving in free space, is diffracted from a properly tailored light mask with a spiral transverse profile. We show how such a diffraction scheme could lead to the production of an atomic Ferris wheel beam.

Non-LTE profiles of the Al I autoionization lines. [for solar model atmospheres

NASA Technical Reports Server (NTRS)

Finn, G. D.; Jefferies, J. T.

1974-01-01

A non-LTE formulation is given for the transfer of radiation in the autoionizing lines of neutral aluminum at 1932 and 1936 A through both the Bilderberg and Harvard-Smithsonian model atmospheres. Numerical solutions for the common source function of these lines and their theoretical line profiles are calculated and compared with the corresponding LTE profiles. The results show that the non-LTE profiles provide a better match with the observations. They also indicate that the continuous opacity of the standard solar models should be increased in this wavelength region if the center-limb variations of observed and theoretical profiles of these lines are to be in reasonable agreement.

Genetic aspects of auto-immune profiles of healthy chickens.

PubMed

Parmentier, Henk K; van der Vaart, Priscilla S; Nieuwland, Mike G B; Savelkoul, Huub F J

2017-09-01

Auto-antibody profiles binding liver antigens differed between chicken lines divergently selected for specific antibody responses to SRBC, and were affected by ageing suggesting both genetic and environmental effects. Presence and levels of IgM and IgG antibodies binding chicken liver cell lysate (CLL) fragments in plasma at 5 weeks of age from 10 individual full sibs and their parents from 5 H srbc and 5 L srbc line families was studied to reveal genetic relations. Non-genetic maternal effects were studied by comparing auto-antibody profiles of 36 weeks old hens from 2 other unrelated lines with the profiles from their chicks at hatch. IgM and IgG antibodies from parents and progeny from both H srbc and L srbc lines bound CLL fragments. Significant line and generation differences and their interactions were found for both isotypes. Higher staining of CLL fragments was usually found for H srbc line birds. Lines were clustered by auto-antibody profiles, but staining by birds of both lines in both generations was very individual for IgG and IgM. The current data with full sibs therefore not supported a genetic basis for auto-antibody profiles. IgG but not IgM auto-antibody profiles of chicks correlated with maternal auto-antibody profiles. The results suggest that the auto-antibody repertoire of healthy chickens is largely stochastically initiated and may be affected by environmental challenges during ageing, but genetic mechanisms may underlie staining intensity of individual bound CLL fragments. The present results suggest that identification of fragments or profiles to be used at early age for genetic selection for health traits is not feasible yet. Secondly, the IgM profile of neonatal chickens seems non-organised independent of the maternal profile, but the neonatal IgG profile is much more related with the maternal profile. Consequences of these findings for disease susceptibility or breeding for optimal health are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Detecting Nanophase Weathering Products with CheMin: Reference Intensity Ratios of Allophane, Aluminosilicate Gel, and Ferrihydrite

NASA Technical Reports Server (NTRS)

Rampe, E. B.; Bish, D. L.; Chipera, S. J.; Morris, R. V.; Achilles, C. N.; Ming, D W.; Blake, D. F.; Anderson, R. C.; Bristow, T. F.; Crisp, A.;

Complex space monofilar approximation of diffraction currents on a conducting half plane

NASA Technical Reports Server (NTRS)

Lindell, I. V.

1987-01-01

Simple approximation of diffraction surface currents on a conducting half plane, due to an incoming plane wave, is obtained with a line current (monofile) in complex space. When compared to an approximating current at the edge, the diffraction pattern is seen to improve by an order of magnitude for a minimal increase of computation effort. Thus, the inconvient Fresnel integral functions can be avoided for quick calculations of diffracted fields and the accuracy is good in other directions than along the half plane. The method can be applied to general problems involving planar metal edges.

Frequency analysis for modulation-enhanced powder diffraction.

PubMed

Chernyshov, Dmitry; Dyadkin, Vadim; van Beek, Wouter; Urakawa, Atsushi

2016-07-01

Periodic modulation of external conditions on a crystalline sample with a consequent analysis of periodic diffraction response has been recently proposed as a tool to enhance experimental sensitivity for minor structural changes. Here the intensity distributions for both a linear and nonlinear structural response induced by a symmetric and periodic stimulus are analysed. The analysis is further extended for powder diffraction when an external perturbation changes not only the intensity of Bragg lines but also their positions. The derived results should serve as a basis for a quantitative modelling of modulation-enhanced diffraction data measured in real conditions.

Wigner analysis of three dimensional pupil with finite lateral aperture

PubMed Central

Chen, Hsi-Hsun; Oh, Se Baek; Zhai, Xiaomin; Tsai, Jui-Chang; Cao, Liang-Cai; Barbastathis, George; Luo, Yuan

2015-01-01

A three dimensional (3D) pupil is an optical element, most commonly implemented on a volume hologram, that processes the incident optical field on a 3D fashion. Here we analyze the diffraction properties of a 3D pupil with finite lateral aperture in the 4-f imaging system configuration, using the Wigner Distribution Function (WDF) formulation. Since 3D imaging pupil is finite in both lateral and longitudinal directions, the WDF of the volume holographic 4-f imager theoretically predicts distinct Bragg diffraction patterns in phase space. These result in asymmetric profiles of diffracted coherent point spread function between degenerate diffraction and Bragg diffraction, elucidating the fundamental performance of volume holographic imaging. Experimental measurements are also presented, confirming the theoretical predictions. PMID:25836443

Monitor Variability of Millimeter Lines in IRC+10216

NASA Astrophysics Data System (ADS)

He, J. H.; Dinh-V-Trung; Hasegawa, T. I.

2017-08-01

A single dish monitoring of millimeter maser lines SiS J = 14-13 and HCN {ν }2={1}f J = 3-2 and several other rotational lines is reported for the archetypal carbon star IRC+10216. Relative line strength variations of 5% ∼ 30% are found for eight molecular line features with respect to selected reference lines. Definite line-shape variations are found in limited velocity intervals of the SiS and HCN line profiles. The asymmetrical line profiles of the two lines are mainly due to the varying components. The dominant varying components of the line profiles have similar periods and phases to the IR light variation, though both quantities show some degree of velocity dependence; there is also variability asymmetry between the blue and red line wings of both lines. Combining the velocities and amplitudes with a wind velocity model, we suggest that the line profile variations are due to SiS and HCN masing lines emanating from the wind acceleration zone. The possible link of the variabilities to thermal, dynamical, and/or chemical processes within or under this region is also discussed.

Conformal growth of Mo/Si multilayers on grating substrates using collimated ion beam sputtering

NASA Astrophysics Data System (ADS)

Voronov, D. L.; Gawlitza, P.; Cambie, R.; Dhuey, S.; Gullikson, E. M.; Warwick, T.; Braun, S.; Yashchuk, V. V.; Padmore, H. A.

2012-05-01

Deposition of multilayers on saw-tooth substrates is a key step in the fabrication of multilayer blazed gratings (MBG) for extreme ultraviolet and soft x-rays. Growth of the multilayers can be perturbed by shadowing effects caused by the highly corrugated surface of the substrates, which results in distortion of the multilayer stack structure and degradation of performance of MBGs. To minimize the shadowing effects, we used an ion-beam sputtering machine with a highly collimated atomic flux to deposit Mo/Si multilayers on saw-tooth substrates. The sputtering conditions were optimized by finding a balance between smoothening and roughening processes in order to minimize degradation of the groove profile in the course of deposition and at the same time to keep the interfaces of a multilayer stack smooth enough for high efficiency. An optimal value of energy of 200 eV for sputtering Kr+ ions was found by deposition of test multilayers on flat substrates at a range of ion energies. Two saw-tooth substrates were deposited at energies of 200 eV and 700 eV for the sputtering ions. It was found that reduction of the ion energy improved the blazing performance of the MBG and resulted in a 40% gain in the diffraction efficiency due to better replication of the groove profile by the multilayer. As a result of the optimization performed, an absolute diffraction efficiency of 28.8% was achieved for the 2nd blaze order of the MBG with a groove density of 7350 lines/mm at a wavelength of 13.5 nm. Details of the growth behavior of the multilayers on flat and saw-tooth substrates are discussed in terms of the linear continuous model of film growth.

Conformal growth of Mo/Si multilayers on grating substrates using collimated ion beam sputtering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Voronov, D. L.; Cambie, R.; Dhuey, S.

2012-05-01

Deposition of multilayers on saw-tooth substrates is a key step in the fabrication of multilayer blazed gratings (MBG) for extreme ultraviolet and soft x-rays. Growth of the multilayers can be perturbed by shadowing effects caused by the highly corrugated surface of the substrates, which results in distortion of the multilayer stack structure and degradation of performance of MBGs. To minimize the shadowing effects, we used an ion-beam sputtering machine with a highly collimated atomic flux to deposit Mo/Si multilayers on saw-tooth substrates. The sputtering conditions were optimized by finding a balance between smoothening and roughening processes in order to minimizemore » degradation of the groove profile in the course of deposition and at the same time to keep the interfaces of a multilayer stack smooth enough for high efficiency. An optimal value of energy of 200 eV for sputtering Kr{sup +} ions was found by deposition of test multilayers on flat substrates at a range of ion energies. Two saw-tooth substrates were deposited at energies of 200 eV and 700 eV for the sputtering ions. It was found that reduction of the ion energy improved the blazing performance of the MBG and resulted in a 40% gain in the diffraction efficiency due to better replication of the groove profile by the multilayer. As a result of the optimization performed, an absolute diffraction efficiency of 28.8% was achieved for the 2nd blaze order of the MBG with a groove density of 7350 lines/mm at a wavelength of 13.5 nm. Details of the growth behavior of the multilayers on flat and saw-tooth substrates are discussed in terms of the linear continuous model of film growth.« less

Conformal growth of Mo/Si multilayers on grating substrates using collimated ion beam sputtering

DOE Office of Scientific and Technical Information (OSTI.GOV)

Voronov, D. L.; Gawlitza, Peter; Cambie, Rossana

2012-05-07

Deposition of multilayers on saw-tooth substrates is a key step in the fabrication of multilayer blazed gratings (MBG) for extreme ultraviolet and soft x-rays. Growth of the multilayers can be perturbed by shadowing effects caused by the highly corrugated surface of the substrates, which results in distortion of the multilayer stack structure and degradation of performance of MBGs. In this study, to minimize the shadowing effects, we used an ion-beamsputtering machine with a highly collimated atomic flux to deposit Mo/Si multilayers on saw-tooth substrates. The sputtering conditions were optimized by finding a balance between smoothening and roughening processes in ordermore » to minimize degradation of the groove profile in the course of deposition and at the same time to keep the interfaces of a multilayer stack smooth enough for high efficiency. An optimal value of energy of 200 eV for sputtering Kr + ions was found by deposition of test multilayers on flat substrates at a range of ion energies. Two saw-tooth substrates were deposited at energies of 200 eV and 700 eV for the sputtering ions. It was found that reduction of the ion energy improved the blazing performance of the MBG and resulted in a 40% gain in the diffraction efficiency due to better replication of the groove profile by the multilayer. As a result of the optimization performed, an absolute diffraction efficiency of 28.8% was achieved for the 2nd blaze order of the MBG with a groove density of 7350 lines/mm at a wavelength of 13.5 nm. Lastly, details of the growth behavior of the multilayers on flat and saw-tooth substrates are discussed in terms of the linear continuous model of film growth.« less

Development of attenuation and diffraction corrections for linear and nonlinear Rayleigh surface waves radiating from a uniform line source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jeong, Hyunjo, E-mail: hjjeong@wku.ac.kr; Cho, Sungjong; Zhang, Shuzeng

2016-04-15

In recent studies with nonlinear Rayleigh surface waves, harmonic generation measurements have been successfully employed to characterize material damage and microstructural changes, and found to be sensitive to early stages of damage process. A nonlinearity parameter of Rayleigh surface waves was derived and frequently measured to quantify the level of damage. The accurate measurement of the nonlinearity parameter generally requires making corrections for beam diffraction and medium attenuation. These effects are not generally known for nonlinear Rayleigh waves, and therefore not properly considered in most of previous studies. In this paper, the nonlinearity parameter for a Rayleigh surface wave ismore » defined from the plane wave displacement solutions. We explicitly define the attenuation and diffraction corrections for fundamental and second harmonic Rayleigh wave beams radiated from a uniform line source. Attenuation corrections are obtained from the quasilinear theory of plane Rayleigh wave equations. To obtain closed-form expressions for diffraction corrections, multi-Gaussian beam (MGB) models are employed to represent the integral solutions derived from the quasilinear theory of the full two-dimensional wave equation without parabolic approximation. Diffraction corrections are presented for a couple of transmitter-receiver geometries, and the effects of making attenuation and diffraction corrections are examined through the simulation of nonlinearity parameter determination in a solid sample.« less

Application of the Hartmann-Tran profile to analysis of H2O spectra

NASA Astrophysics Data System (ADS)

Lisak, D.; Cygan, A.; Bermejo, D.; Domenech, J. L.; Hodges, J. T.; Tran, H.

2015-10-01

The Hartmann-Tran profile (HTP), which has been recently recommended as a new standard in spectroscopic databases, is used to analyze spectra of several lines of H2O diluted in N2, SF6, and in pure H2O. This profile accounts for various mechanisms affecting the line-shape and can be easily computed in terms of combinations of the complex Voigt profile. A multi-spectrum fitting procedure is implemented to simultaneously analyze spectra of H2O transitions acquired at different pressures. Multi-spectrum fitting of the HTP to a theoretical model confirms that this profile provides an accurate description of H2O line-shapes in terms of residuals and accuracy of fitted parameters. This profile and its limiting cases are also fit to measured spectra for three H2O lines in different vibrational bands. The results show that it is possible to obtain accurate HTP line-shape parameters when measured spectra have a sufficiently high signal-to-noise ratio and span a broad range of collisional-to-Doppler line widths. Systematic errors in the line area and differences in retrieved line-shape parameters caused by the overly simplistic line-shape models are quantified. Also limitations of the quadratic speed-dependence model used in the HTP are demonstrated in the case of an SF6 broadened H2O line, which leads to a strongly asymmetric line-shape.

Ultraviolet observations of cool stars. VI - L alpha and Mg II emission line profiles /and a search for flux variability/ in Arcturus

NASA Technical Reports Server (NTRS)

Mcclintock, W.; Moos, H. W.; Henry, R. C.; Linsky, J. L.; Barker, E. S.

1978-01-01

High-precision, high-resolution profiles of the L alpha and Mg II k chromospheric emission lines from Arcturus (alpha Boo) obtained with the Princeton Experimental Package aboard the Copernicus satellite are presented. Asymmetries seen in the profiles of these lines are probably intrinsic to the star, rather than the result of interstellar absorption. In contrast to previous observations of the Ca II K emission line, no evidence is found during a three-year period for variability in the profiles or in the total fluxes from these lines on time scales ranging from hours to months. Also presented is a flux profile of the O I 1302 line and flux upper limits for L beta, O VI 1032, Si III 1206, and O V 1218.

Effect of laser shot peening on precipitation hardened aluminum alloy 6061-T6 using low energy laser

NASA Astrophysics Data System (ADS)

Sathyajith, S.; Kalainathan, S.

2012-03-01

Mechanical properties of engineering material can be improved by introducing compressive residual stress on the material surface and refinement of their microstructure. Variety of mechanical process such as shot peening, water jet peening, ultrasonic peening, laser shot peening were developed in the last decades on this contrast. Among these, lasers shot peening emerged as a novel industrial treatment to improve the crack resistance of turbine blades and the stress corrosion cracking (SCC) of austenic stainless steel in power plants. In this study we successfully performed laser shot peening on precipitation hardened aluminum alloy 6061-T6 with low energy (300 mJ, 1064 nm) Nd:YAG laser using different pulse densities of 22 pulses/mm 2 and 32 pulses/mm 2. Residual stress evaluation based on X-ray diffraction sin 2 ψ method indicates a maximum of 190% percentage increase on surface compressive stress. Depth profile of micro-hardness shows the impact of laser generated shock wave up to 1.2 mm from the surface. Apart from that, the crystalline size and micro-strain on the laser shot peened surfaces have been investigated and compared with the unpeened surface using X-ray diffraction in conjunction with line broadening analysis through the Williamson-Hall plot.

Recommended Isolated-Line Profile for Representing High-Resolution Spectroscoscopic Transitions

NASA Astrophysics Data System (ADS)

Tennyson, J.; Bernath, P. F.; Campargue, A.; Császár, A. G.; Daumont, L.; Gamache, R. R.; Hodges, J. T.; Lisak, D.; Naumenko, O. V.; Rothman, L. S.; Tran, H.; Hartmann, J.-M.; Zobov, N. F.; Buldyreva, J.; Boone, C. D.; De Vizia, M. Domenica; Gianfrani, L.; McPheat, R.; Weidmann, D.; Murray, J.; Ngo, N. H.; Polyansky, O. L.

2014-06-01

Recommendations of an IUPAC Task Group, formed in 2011 on "Intensities and line shapes in high-resolution spectra of water isotopologues from experiment and theory" (Project No. 2011-022-2-100), on line profiles of isolated high-resolution rotational-vibrational transitions perturbed by neutral gas-phase molecules are presented. The well-documented inadequacies of the Voigt profile, used almost universally by databases and radiative-transfer codes to represent pressure effects and Doppler broadening in isolated vibrational-rotational and pure rotational transitions of the water molecule, have resulted in the development of a variety of alternative line profile models. These models capture more of the physics of the influence of pressure on line shapes but, in general, at the price of greater complexity. The Task Group recommends that the partially-Correlated quadratic-Speed-Dependent Hard-Collision profile should be adopted as the appropriate model for high-resolution spectroscopy. For simplicity this should be called the Hartmann-Tran profile (HTP). This profile is sophisticated enough to capture the various collisional contributions to the isolated line shape, can be computed in a straightforward and rapid manner, and reduces to simpler profiles, including the Voigt profile, under certain simplifying assumptions. For further details see: J. Tennyson et al, Pure Appl. Chem., 2014, in press.

Three-Dimensional Model of Holographic Formation of Inhomogeneous PPLC Diffraction Structures

NASA Astrophysics Data System (ADS)

Semkin, A. O.; Sharangovich, S. N.

2018-05-01

A three-dimensional theoretical model of holographic formation of inhomogeneous diffraction structures in composite photopolymer - liquid crystal materials is presented considering both the nonlinearity of recording and the amplitude-phase inhomogeneity of the recording light field. Based on the results of numerical simulation, the kinematics of formations of such structures and their spatial profile are investigated.

Photoelectrochemical fabrication of spectroscopic diffraction gratings, phase 2

NASA Technical Reports Server (NTRS)

Rauh, R. David; Carrabba, Michael M.; Li, Jianguo; Cartland, Robert F.; Hachey, John P.; Mathew, Sam

1990-01-01

This program was directed toward the production of Echelle diffraction gratings by a light-driven, electrochemical etching technique (photoelectrochemical etching). Etching is carried out in single crystal materials, and the differential rate of etching of the different crystallographic planes used to define the groove profiles. Etching of V-groove profiles was first discovered by us during the first phase of this project, which was initially conceived as a general exploration of photoelectrochemical etching techniques for grating fabrication. This highly controllable V-groove etching process was considered to be of high significance for producing low pitch Echelles, and provided the basis for a more extensive Phase 2 investigation.

Synchronous scattering and diffraction from gold nanotextured surfaces with structure factors

NASA Astrophysics Data System (ADS)

Gu, Min-Jhong; Lee, Ming-Tsang; Huang, Chien-Hsun; Wu, Chi-Chun; Chen, Yu-Bin

2018-05-01

Synchronous scattering and diffraction were demonstrated using reflectance from gold nanotextured surfaces at oblique (θi = 15° and 60°) incidence of wavelength λ = 405 nm. Two samples of unique auto-correlation functions were cost-effectively fabricated. Multiple structure factors of their profiles were confirmed with Fourier expansions. Bi-directional reflectance function (BRDF) from these samples provided experimental proofs. On the other hand, standard deviation of height and unique auto-correlation function of each sample were used to generate surfaces numerically. Comparing their BRDF with those of totally random rough surfaces further suggested that structure factors in profile could reduce specular reflection more than totally random roughness.

Retrieving cirrus microphysical properties from stellar aureoles

NASA Astrophysics Data System (ADS)

DeVore, J. G.; Kristl, J. A.; Rappaport, S. A.

2013-06-01

The aureoles around stars caused by thin cirrus limit nighttime measurement opportunities for ground-based astronomy, but can provide information on high-altitude ice crystals for climate research. In this paper we attempt to demonstrate quantitatively how this works. Aureole profiles can be followed out to ~0.2° from stars and ~0.5° from Jupiter. Interpretation of diffracted starlight is similar to that for sunlight, but emphasizes larger particles. Stellar diffraction profiles are very distinctive, typically being approximately flat out to a critical angle followed by gradually steepening power-law falloff with slope less steep than -3. Using the relationship between the phase function for diffraction and the average Fourier transform of the projected area of complex ice crystals, we show that defining particle size in terms of average projected area normal to the propagation direction of the starlight leads to a simple, analytic approximation representing large-particle diffraction that is nearly independent of crystal habit. A similar analytic approximation for the diffraction aureole allows it to be separated from the point spread function and the sky background. Multiple scattering is deconvolved using the Hankel transform leading to the diffraction phase function. Application of constrained numerical inversion to the phase function then yields a solution for the particle size distribution in the range between ~50 μm and ~400 μm. Stellar aureole measurements can provide one of the very few, as well as least expensive, methods for retrieving cirrus microphysical properties from ground-based observations.

Super-massive binary black holes and emission lines in active galactic nuclei

NASA Astrophysics Data System (ADS)

Popović, Luka Č.

2012-02-01

It is now agreed that mergers play an essential role in the evolution of galaxies and therefore that mergers of supermassive black holes (SMBHs) must have been common. We see the consequences of past supermassive binary black holes (SMBs) in the light profiles of so-called 'core ellipticals' and a small number of SMBs have been detected. However, the evolution of SMBs is poorly understood. Theory predicts that SMBs should spend a substantial amount of time orbiting at velocities of a few thousand kilometers per second. If the SMBs are surrounded by gas observational effects might be expected from accretion onto one or both of the SMBHs. This could result in a binary Active Galactic Nucleus (AGN) system. Like a single AGN, such a system would emit a broad band electromagnetic spectrum and broad and narrow emission lines. The broad emission spectral lines emitted from AGNs are our main probe of the geometry and physics of the broad line region (BLR) close to the SMBH. There is a group of AGNs that emit very broad and complex line profiles, showing two displaced peaks, one blueshifted and one redshifted from the systemic velocity defined by the narrow lines, or a single such peak. It has been proposed that such line shapes could indicate an SMB system. We discuss here how the presence of an SMB will affect the BLRs of AGNs and what the observational consequences might be. We review previous claims of SMBs based on broad line profiles and find that they may have non-SMB explanations as a consequence of a complex BLR structure. Because of these effects it is very hard to put limits on the number of SMBs from broad line profiles. It is still possible, however, that unusual broad line profiles in combination with other observational effects (line ratios, quasi-periodical oscillations, spectropolarimetry, etc.) could be used for SMBs detection. Some narrow lines (e.g., [O III]) in some AGNs show a double-peaked profile. Such profiles can be caused by streams in the Narrow Line Region (NLR), but may also indicate the presence of a kilo-parsec scale mergers. A few objects indicated as double-peaked narrow line emitters are confirmed as kpc-scale margers, but double-peaked narrow line profiles are mostly caused by the complex NLR geometry. We briefly discuss the expected line profile of broad Fe Kα that probably originated in the accretion disk(s) around SMBs. This line may also be very complex and indicate the complex disk geometry or/and an SMB presence. Finally we consider rare configurations where a SMB system might be gravitationally lensed by a foreground galaxy, and discuss the expected line profiles in these systems.

Design and characteristic analysis of shaping optics for optical trepanning

NASA Astrophysics Data System (ADS)

Zeng, D.; Latham, W. P.; Kar, A.

2005-08-01

Optical trepanning is a new laser drilling method using an annular beam. The annular beams allow numerous irradiance profiles to supply laser energy to the workpiece and thus provide more flexibility in affecting the hole quality than a traditional circular laser beam. The refractive axicon system has been designed to generating a collimated annular beam. In this article, calculations of intensity distributions produced by this refractive system are made by evaluating the Kirchhoff-Fresnel diffraction. It is shown that the refractive system is able to transform a Gaussian beam into a full Gaussian annular beam. The base angle of the axicon lens, input laser beam diameter and intensity profiles are found to be important factors for the axcion refractive system. Their effects on the annular beam profiles are analyzed based on the numerical solutions of the diffraction patterns.

EUV efficiency of a 6000-grooves per mm diffraction grating

NASA Technical Reports Server (NTRS)

Hurwitz, Mark; Bowyer, Stuart; Edelstein, Jerry; Harada, Tatsuo; Kita, Toshiaki

1990-01-01

In order to explore whether grooves ruled mechanically at a density of 6000 per mm can perform well at EUV wavelengths, a sample grating is measured with this density in an EUV calibration facility. Measurements are presented of the planar uniform line-space diffraction grating's efficiency and large-angle scattering.

Magnetic field gradient driven self-assembly of superparamagnetic nanoparticles using programmable magnetically-recorded templates

NASA Astrophysics Data System (ADS)

Ye, L.; Qi, B.; Lawton, T. G.; Mefford, O. T.; Rinaldi, C.; Garzon, S.; Crawford, T. M.

2013-03-01

Using the enormous magnetic field gradients (100 MT/m @ z =20 nm) present near the surface of magnetic recording media, we demonstrate the fabrication of diffraction gratings with lines consisting entirely of magnetic nanoparticles assembled from a colloidal fluid onto a disk drive medium, followed by transfer to a flexible and transparent polymer thin film. These nanomanufactured gratings have line spacings programmed with commercial magnetic recording and are inherently concave with radii of curvature controlled by varying the polymer film thickness. The diffracted intensity increases non-monotonically with the length of time the colloidal fluid remains on the disk surface. In addition to comparing longitudinal and perpendicular magnetic recording, a combination of spectral diffraction efficiency measurements, magnetometry, scanning electron microscopy and inductively coupled plasma atomic emmission spectroscopy of these gratings are employed to understand colloidal nanoparticle dynamics in this extreme gradient limit. Such experiments are necessary to optimize nanoparticle assembly and obtain uniform patterned features. This low-cost and sustainable approach to nanomanufacturing could enable low-cost, high-quality diffraction gratings as well as more complex polymer nanocomposite materials assembled with single-nanometer precision.

Glass transition in ferroic glass K x (ND4)1-x D2PO4: a complete x-ray diffraction line shape analysis

NASA Astrophysics Data System (ADS)

Ranjan Choudhury, Rajul; Chitra, R.; Jayakrishnan, V. B.

2016-03-01

Quenching of dynamic disorder in glassy systems is termed as the glass transition. Ferroic glasses belong to the class of paracrystalline materials having crystallographic order in-between that of a perfect crystal and amorphous material, a classic example of ferroic glass is the solid solution of ferroelectric deuterated potassium dihydrogen phosphate and antiferroelectric deuterated ammonium dihydrogen phosphate. Lowering temperature of this ferroic glass can lead to a glass transition to a quenched disordered state. The subtle atomic rearrangement that takes place at such a glass transition can be revealed by careful examination of the temperature induced changes occurring in the x-ray powder diffraction (XRD) patterns of these materials. Hence we report here results of a complete diffraction line shape analysis of the XRD patterns recorded at different temperatures from deuterated mixed crystals DK x A1-x DP with mixing concentration x ranging as 0 < x < 1. Changes observed in diffraction peak shapes have been explained on the basis of structural rearrangements induced by changing O-D-O hydrogen bond dynamics in these paracrystals.

Metallic line profiles of the AOV star Vega

NASA Technical Reports Server (NTRS)

Fletcher, J. Murray; Gulliver, Austin F.; Adelman, Saul J.; Crowley, Charles R.

1990-01-01

High dispersion ultrahigh signal to noise Reticon spectra of Vega were obtained with the coude spectrograph of the 1.2 m telescope. A mean signal to noise ratio of 2500 over the spectral region lambdas from 3825 to 5435 was achieved. Examination of the line profiles confirmed the presence of two different types of profiles which were previously seen in IIIaJ and lower signal to noise Reticon spectra. The profiles of the strong lines are essentially classical rotational profiles with enhanced wings which are slightly stronger than expected while those of weak lines are clearly flat-bottomed resulting in a trapezoidal appearance. A few possible theoretical explanations are presented.

Metallic line profiles of the AO V star Vega

NASA Technical Reports Server (NTRS)

Gulliver, Austin F.; Adelman, Saul J.; Cowley, Charles R.; Fletcher, J. M.

1991-01-01

High dispersion ultrahigh signal to noise Reticon spectra of Vega were obtained with the coude spectrograph of the 1.2 m telescope. A mean signal to noise ratio of 2500 over the spectral region lambdas from 3825 to 5435 was achieved. Examination of the line profiles confirmed the presence of two different types of profiles which were previously seen in IIIaJ and lower signal to noise Reticon spectra. The profiles of the strong lines are essentially classical rotational profiles with enhanced wings which are slightly stronger than expected while those of weak lines are clearly flat-bottomed resulting in a trapezoidal appearance. A few possible theoretical explanations are presented.

Measurement of strain in Al-Cu interconnect lines with x-ray microdiffraction

NASA Astrophysics Data System (ADS)

Solak, H. H.; Vladimirsky, Y.; Cerrina, F.; Lai, B.; Yun, W.; Cai, Z.; Ilinski, P.; Legnini, D.; Rodrigues, W.

1999-07-01

We report measurement of strain in patterned Al-Cu interconnect lines with x-ray microdiffraction technique with a ˜1 μm spatial resolution. Monochromatized x rays from an undulator were focused on the sample using a phase fresnel zone plate and diffracted light was collected by an area detector in a symmetric, angle dispersive x-ray diffraction geometry. Measurements were made before and after the line sample was stressed for electromigration. Results show an increase in inter- and intra-grain strain variation after the testing. Differences in strain behavior of grains with (111) and (200) crystallographic planes parallel to the substrate surface were observed. A position dependent variation of strain after the testing was measured whereas no such dependence was found before the testing.

MONOCULAR DIPLOPIA DUE TO SPHEROCYLINDRICAL REFRACTIVE ERRORS (AN AMERICAN OPHTHALMOLOGICAL SOCIETY THESIS)

PubMed Central

Archer, Steven M.

2007-01-01

Purpose Ordinary spherocylindrical refractive errors have been recognized as a cause of monocular diplopia for over a century, yet explanation of this phenomenon using geometrical optics has remained problematic. This study tests the hypothesis that the diffraction theory treatment of refractive errors will provide a more satisfactory explanation of monocular diplopia. Methods Diffraction theory calculations were carried out for modulation transfer functions, point spread functions, and line spread functions under conditions of defocus, astigmatism, and mixed spherocylindrical refractive errors. Defocused photographs of inked and projected black lines were made to demonstrate the predicted consequences of the theoretical calculations. Results For certain amounts of defocus, line spread functions resulting from spherical defocus are predicted to have a bimodal intensity distribution that could provide the basis for diplopia with line targets. Multimodal intensity distributions are predicted in point spread functions and provide a basis for diplopia or polyopia of point targets under conditions of astigmatism. The predicted doubling effect is evident in defocused photographs of black lines, but the effect is not as robust as the subjective experience of monocular diplopia. Conclusions Monocular diplopia due to ordinary refractive errors can be predicted from diffraction theory. Higher-order aberrations—such as spherical aberration—are not necessary but may, under some circumstances, enhance the features of monocular diplopia. The physical basis for monocular diplopia is relatively subtle, and enhancement by neural processing is probably needed to account for the robustness of the percept. PMID:18427616

Evidence of redshifts in the average solar line profiles of C IV and Si IV from OSO-8 observations

NASA Technical Reports Server (NTRS)

Roussel-Dupre, D.; Shine, R. A.

1982-01-01

Line profiles of C IV and Si V obtained by the Colorado spectrometer on OSO-8 are presented. It is shown that the mean profiles are redshifted with a magnitude varying from 6-20 km/s, and with a mean of 12 km/s. An apparent average downflow of material in the 50,000-100,000 K temperature range is measured. The redshifts are observed in the line center positions of spatially and temporally averaged profiles and are measured either relative to chromospheric Si I lines or from a comparison of sun center and limb profiles. The observations of 6-20 km/s redshifts place constraints on the mechanisms that dominate EUV line emission since it requires a strong weighting of the emission in regions of downward moving material, and since there is little evidence for corresponding upward moving materials in these lines.

The generalization of upper atmospheric wind and temperature based on the Voigt line shape profile.

PubMed

Zhang, Chunmin; He, Jian

2006-12-25

The principle of probing the upper atmospheric wind field, which is the Voigt profile spectral line shape, is presented for the first time. By the Fourier Transform of Voigt profile, with the Imaging Spectroscope and the Doppler effect of electromagnetic wave, the distribution and calculation formulae of the velocity field, temperature field, and pressure field of the upper atmosphere wind field are given. The probed source is the two major aurora emission lines originated from the metastable O(1S) and O(1D) at 557.7nm and 630.0nm. From computer simulation and error analysis, the Voigt profile, which is the correlation of the Gaussian profile and Lorentzian profile, is closest to the actual airglow emission lines.

Détermination du profil de modulation des réseaux holographiques de phase

NASA Astrophysics Data System (ADS)

Mechahougui, S.; Harthong, J.; Medjahed, A.

1993-12-01

The complete knowledge of the geometrical and physic-chemical parameters of a periodically modulated volume material, permits the determination of the diffraction picture. Such a purely mathematical and numerical determination is of great scientific and technological interest. The modulation profile (given by its Fourier coefficients) is one of these parameters. It can be determinated a posteriori only by the measurement of the different diffracted intensities at different orders. Starting from this idea, we can achieve a new method (theoritically exact) which permits the study of the diffraction of an electromagnetic plane wave by a dielectric grating. This method leads to the numerical treatment of ordinary differential equation with variable by periodic coefficients. The method is presented here for the classical case of a wave with electric polarization parallel to the grating. For the analysis of the modulation profile, we have considered realistic models of profiles, contrary to the current models, which have only a numerical existence. In order to achieve our experimental work, we have developed two experimental set-up: the first for the recording and the second for the analysis of diffractive elements. The whole set-up can be directed with the aid of a software from a personal computer. The validity of results are discussed. La connaissance parfaite des paramètres géométriques et physico-chimiques d'un matériau de volume modulé périodiquement, donne une bonne connaissance de la figure de diffraction. Celle-ci a une grande importance scientifique et technologique. Le profil de modulation (donné par ses coefficients de Fourier) est l'un de ces paramètres qui ne peut être déterminé a posteriori qu'à partir de la répartition d'intensité entre les différents ordres. A partir de cette idée, nous avons établi une méthode exacte permettant l'étude de la diffraction d'une onde plane électromagnétique par un réseau diélectrique, qui conduit au traitement numérique d'une équation différentielle à coefficients variables. La méthode est donnée pour le cas classique où le champ électrique est parallèle au plan du réseau. Pour analyser l'influence du profil de modulation, on considère des modèles mathématiques réalistes et non (comme il est courant dans la littérature) des modèles physiques irréalisables. Pour notre travail expérimental nous avons mis au point deux montages : le premier pour l'enregistrement et le second pour l'analyse. Ce dernier est totalement automatisé et piloté par un ordinateur. Les résultats obtenus sont largement discutés.

Diffraction and imaging study of imperfections of crystallized lysozyme with coherent X-rays

NASA Technical Reports Server (NTRS)

Hu, Z. W.; Chu, Y. S.; Lai, B.; Thomas, B. R.; Chernov, A. A.

2004-01-01

Phase-contrast X-ray diffraction imaging and high-angular-resolution diffraction combined with phase-contrast radiographic imaging were employed to characterize defects and perfection of a uniformly grown tetragonal lysozyme crystal in the symmetric Laue case. The full-width at half-maximum (FWHM) of a 4 4 0 rocking curve measured from the original crystal was approximately 16.7 arcsec and imperfections including line defects, inclusions and other microdefects were observed in the diffraction images of the crystal. The observed line defects carry distinct dislocation features running approximately along the <1 1 0> growth front and have been found to originate mostly in a central growth area and occasionally in outer growth regions. Inclusions of impurities or formations of foreign particles in the central growth region are resolved in the images with high sensitivity to defects. Slow dehydration led to the broadening of a fairly symmetric 4 4 0 rocking curve by a factor of approximately 2.6, which was primarily attributed to the dehydration-induced microscopic effects that are clearly shown in X-ray diffraction images. The details of the observed defects and the significant change in the revealed microstructures with drying provide insight into the nature of imperfections, nucleation and growth, and the properties of protein crystals.

Balmer line profiles for infalling T Tauri envelopes

NASA Technical Reports Server (NTRS)

Calvet, Nuria; Hartmann, Lee

1992-01-01

The possibility that the Balmer emission lines of T Tauri stars arise in infalling envelopes rather than winds is considered. Line profiles for the upper Balmer lines are presented for models with cone geometry, intended to simulate the basic features of magnetospheric accretion from a circumstellar disk. An escape probability treatment is used to determine line source functions in nonspherically symmetric geometry. Thermalization effects are found to produce nearly symmetric H-alpha line profiles at the same time the higher Balmer series lines exhibit inverse P Cygni profiles. The infall models produce centrally peaked emission line wings, in good agreement with observations of many T Tauri stars. It is suggested that the Balmer emission of many T Tauri stars may be produced in an infalling envelope, with blue shifted absorption contributed by an overlying wind. Some of the observed narrow absorption components with small blueshifts may also arise in the accretion column.

Aeroacoustic diffraction and dissipation by a short propeller cowl in subsonic flight

NASA Technical Reports Server (NTRS)

Martinez, Rudolph

1993-01-01

This report develops and applies an aeroacoustic diffraction theory for a duct, or cowl, placed around modelled sources of propeller noise. The regime of flight speed is high subsonic. The modelled cowl's inner wall contains a liner with axially variable properties. Its exterior is rigid. The analysis replaces both sides with an unsteady lifting surface coupled to a dynamic thickness problem. The resulting pair of aeroacoustic governing equations for a lined 'ring wing' is valid both for a passive and for an active liner. Their numerical solution yields the effective dipole and monopole distributions of the shrouding system and thereby determines the cowl-diffracted component of the total radiated field. The sample calculations here include a preliminary parametric search for that liner layout which maximizes the cowl's shielding effectiveness. The main conclusion of the study is that a short cowl, passively lined, should provide moderate reductions in propeller noise.

Computer Generated Diffraction Patterns Of Rough Surfaces

NASA Astrophysics Data System (ADS)

Rakels, Jan H.

1989-03-01

It is generally accepted, that optical methods are the most promising for the in-process measurement of surface finish. These methods have the advantages of being non-contacting and fast data acquisition. In the Micro-Engineering Centre at the University of Warwick, an optical sensor has been devised which can measure the rms roughness, slope and wavelength of turned and precision ground surfaces. The operation of this device is based upon the Kirchhoff-Fresnel diffraction integral. Application of this theory to ideal turned surfaces is straightforward, and indeed the theoretically calculated diffraction patterns are in close agreement with patterns produced by an actual optical instrument. Since it is mathematically difficult to introduce real surface profiles into the diffraction integral, a computer program has been devised, which simulates the operation of the optical sensor. The program produces a diffraction pattern as a graphical output. Comparison between computer generated and actual diffraction patterns of the same surfaces show a high correlation.

Optimization of Surface Roughness Parameters of Al-6351 Alloy in EDC Process: A Taguchi Coupled Fuzzy Logic Approach

NASA Astrophysics Data System (ADS)

Kar, Siddhartha; Chakraborty, Sujoy; Dey, Vidyut; Ghosh, Subrata Kumar

2017-10-01

This paper investigates the application of Taguchi method with fuzzy logic for multi objective optimization of roughness parameters in electro discharge coating process of Al-6351 alloy with powder metallurgical compacted SiC/Cu tool. A Taguchi L16 orthogonal array was employed to investigate the roughness parameters by varying tool parameters like composition and compaction load and electro discharge machining parameters like pulse-on time and peak current. Crucial roughness parameters like Centre line average roughness, Average maximum height of the profile and Mean spacing of local peaks of the profile were measured on the coated specimen. The signal to noise ratios were fuzzified to optimize the roughness parameters through a single comprehensive output measure (COM). Best COM obtained with lower values of compaction load, pulse-on time and current and 30:70 (SiC:Cu) composition of tool. Analysis of variance is carried out and a significant COM model is observed with peak current yielding highest contribution followed by pulse-on time, compaction load and composition. The deposited layer is characterised by X-Ray Diffraction analysis which confirmed the presence of tool materials on the work piece surface.

Single molecule fluorescence microscopy for ultra-sensitive RNA expression profiling

NASA Astrophysics Data System (ADS)

Hesse, Jan; Jacak, Jaroslaw; Regl, Gerhard; Eichberger, Thomas; Aberger, Fritz; Schlapak, Robert; Howorka, Stefan; Muresan, Leila; Frischauf, Anna-Maria; Schütz, Gerhard J.

2007-02-01

We developed a microarray analysis platform for ultra-sensitive RNA expression profiling of minute samples. It utilizes a novel scanning system for single molecule fluorescence detection on cm2 size samples in combination with specialized biochips, optimized for low autofluorescence and weak unspecific adsorption. 20 μg total RNA was extracted from 10 6 cells of a human keratinocyte cell line (HaCaT) and reversely transcribed in the presence of Alexa647-aha-dUTP. 1% of the resulting labeled cDNA was used for complex hybridization to a custom-made oligonucleotide microarray representing a set of 125 different genes. For low abundant genes, individual cDNA molecules hybridized to the microarray spots could be resolved. Single cDNA molecules hybridized to the chip surface appeared as diffraction limited features in the fluorescence images. The à trous wavelet method was utilized for localization and counting of the separated cDNA signals. Subsequently, the degree of labeling of the localized cDNA molecules was determined by brightness analysis for the different genes. Variations by factors up to 6 were found, which in conventional microarray analysis would result in a misrepresentation of the relative abundance of mRNAs.

On the symmetry and crystal structures of Ba{sub 2}LaIrO{sub 6}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fu, W.T., E-mail: w.fu@chem.leidenuniv.n; Goetz, R.J.; IJdo, D.J.W.

2010-02-15

Accurate profile analysis of X-ray diffraction data was carried out to settle recent dispute on the symmetry and crystal structures of the double perovskite Ba{sub 2}LaIrO{sub 6}. Even through careful comparison of the full-width at half-maximum values, we found no evidence for Ba{sub 2}LaIrO{sub 6} adopting either monoclinic (I2/m) or mixed rhombohedral (R3-bar) and monoclinic (I2/m) structures at room temperature, becoming triclinic (I1-bar) at below about 200 K. The correct space group is just R3-bar at temperatures between 82 and 653 K. Furthermore, the R3-bar->Fm3-barm phase transition does occur in Ba{sub 2}LaIrO{sub 6}, but the transition temperature is found tomore » be much higher than the reported value. - Graphical abstract: Observed (crosses) and calculated (continuous line) profiles of Ba{sub 2}LaIrO{sub 6} at some selected temperature showing the region containing the basic (222), (321) and (400) reflections. Tick marks below indicate the positions of the allowed Bragg's reflections.« less

The Crystal Structure of Illite/Smectite.

DTIC Science & Technology

1988-04-04

summarized from Tellier and Reynolds (1987). Figure 3 shows a comparison between experimental and calculated diffraction patterns for the ethylene glycol...PUBLICATIONS Tellier . K. and Reynolds, R. C. (1987) Calculation of one-dimensional X-ray diffraction profiles of interstratified illite/smectite as...Abst.) 24th Annual fMeet Clay Min. Soc., Socorro, N. M., p. 115 PARTICIPATING SCIENTIFIC PERSONNEL Kathleen Tellier : Dept. of Earth Sciences

HiSPoD: a program for high-speed polychromatic X-ray diffraction experiments and data analysis on polycrystalline samples

DOE PAGES

Sun, Tao; Fezzaa, Kamel

2016-06-17

Here, a high-speed X-ray diffraction technique was recently developed at the 32-ID-B beamline of the Advanced Photon Source for studying highly dynamic, yet non-repeatable and irreversible, materials processes. In experiments, the microstructure evolution in a single material event is probed by recording a series of diffraction patterns with extremely short exposure time and high frame rate. Owing to the limited flux in a short pulse and the polychromatic nature of the incident X-rays, analysis of the diffraction data is challenging. Here, HiSPoD, a stand-alone Matlab-based software for analyzing the polychromatic X-ray diffraction data from polycrystalline samples, is described. With HiSPoD,more » researchers are able to perform diffraction peak indexing, extraction of one-dimensional intensity profiles by integrating a two-dimensional diffraction pattern, and, more importantly, quantitative numerical simulations to obtain precise sample structure information.« less

Zone-boundary optimization for direct laser writing of continuous-relief diffractive optical elements.

PubMed

Korolkov, Victor P; Nasyrov, Ruslan K; Shimansky, Ruslan V

2006-01-01

Enhancing the diffraction efficiency of continuous-relief diffractive optical elements fabricated by direct laser writing is discussed. A new method of zone-boundary optimization is proposed to correct exposure data only in narrow areas along the boundaries of diffractive zones. The optimization decreases the loss of diffraction efficiency related to convolution of a desired phase profile with a writing-beam intensity distribution. A simplified stepped transition function that describes optimized exposure data near zone boundaries can be made universal for a wide range of zone periods. The approach permits a similar increase in the diffraction efficiency as an individual-pixel optimization but with fewer computation efforts. Computer simulations demonstrated that the zone-boundary optimization for a 6 microm period grating increases the efficiency by 7% and 14.5% for 0.6 microm and 1.65 microm writing-spot diameters, respectively. The diffraction efficiency of as much as 65%-90% for 4-10 microm zone periods was obtained experimentally with this method.

Observations of emission in bright, low redshift quasars

NASA Technical Reports Server (NTRS)

1983-01-01

Ultraviolet, infrared, and optical spectra were combined to obtain a data set sample as broad as possible in the range of hydrogen lines in individual quasars. From the measured Lyman fluxes, coupled with Balmer and Paschen line fluxes measured in these same objects, an effort was made to establish observational constraints that would guide models of the broad emission line regions of quasars. It was found that IUE spectra were generally of sufficiently high quality to derive line profiles of the ultraviolet lines Lyman alpha and CIV 1550 A, which were compared to the Balmer line profiles. The objects observed and the line fluxes are tabulated. Plots of line profiles are included.

Coherent diffraction surface imaging in reflection geometry.

PubMed

Marathe, Shashidhara; Kim, S S; Kim, S N; Kim, Chan; Kang, H C; Nickles, P V; Noh, D Y

2010-03-29

We present a reflection based coherent diffraction imaging method which can be used to reconstruct a non periodic surface image from a diffraction amplitude measured in reflection geometry. Using a He-Ne laser, we demonstrated that a surface image can be reconstructed solely from the reflected intensity from a surface without relying on any prior knowledge of the sample object or the object support. The reconstructed phase image of the exit wave is particularly interesting since it can be used to obtain quantitative information of the surface depth profile or the phase change during the reflection process. We believe that this work will broaden the application areas of coherent diffraction imaging techniques using light sources with limited penetration depth.

High-energy, 2µm laser transmitter for coherent wind LIDAR

NASA Astrophysics Data System (ADS)

Singh, Upendra N.; Yu, Jirong; Kavaya, Michael J.; Koch, Grady J.

2017-11-01

A coherent Doppler lidar at 2μm wavelength has been built with higher output energy (300 mJ) than previously available. The laser transmitter is based on the solid-state Ho:Tm:LuLiF, a NASA Langley Research Center invented laser material for higher extraction efficiency. This diode pumped injection seeded MOPA has a transform limited line width and diffraction limited beam quality. NASA Langley Research Center is developing coherent wind lidar transmitter technology at eye-safe wavelength for satellite-based observation of wind on a global scale. The ability to profile wind is a key measurement for understanding and predicting atmospheric dynamics and is a critical measurement for improving weather forecasting and climate modeling. We would describe the development and performance of an engineering hardened 2μm laser transmitter for coherent Doppler wind measurement from ground/aircraft/space platform.

Effective bichromatic potential for ultra-high Q-factor photonic crystal slab cavities

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alpeggiani, Filippo, E-mail: filippo.alpeggiani01@ateneopv.it; Andreani, Lucio Claudio; Gerace, Dario

2015-12-28

We introduce a confinement mechanism in photonic crystal slab cavities, which relies on the superposition of two incommensurate one-dimensional lattices in a line-defect waveguide. It is shown that the resulting photonic profile realizes an effective quasi-periodic bichromatic potential for the electromagnetic field confinement yielding extremely high quality (Q) factor nanocavities, while simultaneously keeping the mode volume close to the diffraction limit. We apply these concepts to pillar- and hole-based photonic crystal slab cavities, respectively, and a Q-factor improvement by over an order of magnitude is shown over existing designs, especially in pillar-based structures. Thanks to the generality and easy adaptationmore » of such confinement mechanism to a broad class of cavity designs and photonic lattices, this work opens interesting routes for applications where enhanced light–matter interaction in photonic crystal structures is required.« less

The effects of welded joint characteristics on its properties in HDPE thermal fusion welding

NASA Astrophysics Data System (ADS)

Dai, Hongbin; Peng, Jun

2017-05-01

In this paper, PE100 pipes with the diameter of 200 mm and the thickness of 11.9 mm were used as material. The welded joints were obtained in different welding pressures with the optimal welding temperature of 220∘C. Reheating process on the welded joints with the temperature of 130∘C was carried out. The joints exhibited X-type, and the cause of X-type joints was discussed. The temperature field in the forming process of welded joints was measured, and tensile and bending tests on welded joints were carried out. The fracture surface of welded joints was observed by scanning electron microscopy (SEM), and crystallinity calculation was taken by X-ray diffraction (XRD). The mechanism of X-type weld profile effects on welded joints properties was analyzed. It was concluded that the mechanical properties of welded joints decrease with the reduced X distance between lines.

Shear-Coupled Grain Growth and Texture Development in a Nanocrystalline Ni-Fe Alloy during Cold Rolling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Li; Ungár, Tamás; Toth, Laszlo S.

The evolution of texture, grain size, grain shape, dislocation and twin density has been determined by synchrotron X-ray diffraction and line profile analysis in a nanocrystalline Ni- Fe alloy after cold rolling along different directions related to the initial fiber and the long axis of grains. The texture evolution has been simulated by the Taylor-type relaxed constraints viscoplastic polycrystal model. The simulations were based on the activity of partial dislocations in correlation with the experimental results of dislocation density determination. The concept of stress-induced shear-coupling is supported and strengthened by both the texture simulations and the experimentally determined evolution ofmore » the microstructure parameters. Grain-growth and texture evolution are shown to proceed by the shear-coupling mechanism supported by dislocation activity as long as the grain size is not smaller than about 20 nm.« less

Induced Marine Fungus Chondrostereum sp. as a Means of Producing New Sesquiterpenoids Chondrosterins I and J by Using Glycerol as the Carbon Source

PubMed Central

Li, Hou-Jin; Jiang, Wen-Han; Liang, Wan-Ling; Huang, Jia-Xin; Mo, Yu-Fei; Ding, Yan-Qing; Lam, Chi-Keung; Qian, Xiao-Jun; Zhu, Xiao-Feng; Lan, Wen-Jian

2014-01-01

Chondrostereum sp., a marine fungus isolated from a soft coral Sarcophyton tortuosum, can yield hirsutane framework sesquiterpenoids. However, the metabolites profiles vary dramatically with the composition change of the culture media. This fungus was cultured in a liquid medium containing glycerol as the carbon source, and two new metabolites, chondrosterins I and J (1 and 2), were obtained. Their structures were elucidated primarily based on MS, NMR and X-ray single-crystal diffraction data. By comparison with the known hirsutane sesquiterpenoids, chondrosterins I and J have unique structural features, including a methyl was migrated from C-2 to C-6, and the methyl at C-3 was carboxylated. Compound 2 exhibited potent cytotoxic activities against the cancer cell lines CNE-1 and CNE-2 with the IC50 values of 1.32 and 0.56 μM. PMID:24402176

Defect structure in electrodeposited nanocrystalline Ni layers with different Mo concentrations

NASA Astrophysics Data System (ADS)

Kapoor, Garima; Péter, László; Fekete, Éva; Gubicza, Jenő

2018-05-01

The effect of molybdenum (Mo) alloying on the lattice defect structure in electrodeposited nanocrystalline nickel (Ni) films was studied. The electrodeposited layers were prepared on copper substrate at room temperature, with a constant current density and pH value. The chemical composition of these layers was determined by EDS. In addition, X-ray diffraction line profile analysis was carried out to study the microstructural parameters such as the crystallite size, the dislocation density and the stacking fault probability. It was found that the higher Mo content yielded more than one order of magnitude larger dislocation density while the crystallite size was only slightly smaller. In addition, the twin boundary formation activity during deposition increased with increasing Mo concentration. The results obtained on electrodeposited layers were compared with previous research carried out on bulk nanocrystalline Ni-Mo materials with similar compositions but processed by severe plastic deformation.

An Analysis of Water Line Profiles in Star Formation Regions Observed by SWAS

NASA Technical Reports Server (NTRS)

Ashby, Matthew L. N.; Bergin, Edwin A.; Plume, Rene; Carpenter, John M.; Neufeld, David A.; Chin, Gordon; Erickson, Neal R.; Goldsmith, Paul F.; Harwit, Martin; Howe, J. E.

2000-01-01

We present spectral line profiles for the 557 GHz 1(sub 1,0) yields 1(sub 0,1) ground-state rotational transition of ortho-H2(16)O for 18 galactic star formation regions observed by SWAS. 2 Water is unambiguously detected in every source. The line profiles exhibit a wide variety of shapes, including single-peaked spectra and self-reversed profiles. We interpret these profiles using a Monte Carlo code to model the radiative transport. The observed variations in the line profiles can be explained by variations in the relative strengths of the bulk flow and small-scale turbulent motions within the clouds. Bulk flow (infall, outflow) must be present in some cloud cores, and in certain cases this bulk flow dominates the turbulent motions.

Magnetospheric accretion models for T Tauri stars. 1: Balmer line profiles without rotation

NASA Technical Reports Server (NTRS)

Hartmann, Lee; Hewett, Robert; Calvet, Nuria

1994-01-01

We argue that the strong emission lines of T Tauri stars are generally produced in infalling envelopes. Simple models of infall constrained to a dipolar magnetic field geometry explain many peculiarities of observed line profiles that are difficult, if not impossible, to reproduce with wind models. Radiative transfer effects explain why certain lines can appear quite symmetric while other lines simultaneously exhibit inverse P Cygni profiles, without recourse to complicated velocity fields. The success of the infall models in accounting for qualitative features of observed line profiles supports the proposal that stellar magnetospheres disrupt disk accretion in T Tauri stars, that true boundary layers are not usually present in T Tauri stars, and that the observed 'blue veiling' emission arises from the base of the magnetospheric accretion column.

Mitigation of X-ray damage in macromolecular crystallography by submicrometre line focusing.

PubMed

Finfrock, Y Zou; Stern, Edward A; Alkire, R W; Kas, Joshua J; Evans-Lutterodt, Kenneth; Stein, Aaron; Duke, Norma; Lazarski, Krzysztof; Joachimiak, Andrzej

2013-08-01

Reported here are measurements of the penetration depth and spatial distribution of photoelectron (PE) damage excited by 18.6 keV X-ray photons in a lysozyme crystal with a vertical submicrometre line-focus beam of 0.7 µm full-width half-maximum (FWHM). The experimental results determined that the penetration depth of PEs is 5 ± 0.5 µm with a monotonically decreasing spatial distribution shape, resulting in mitigation of diffraction signal damage. This does not agree with previous theoretical predication that the mitigation of damage requires a peak of damage outside the focus. A new improved calculation provides some qualitative agreement with the experimental results, but significant errors still remain. The mitigation of radiation damage by line focusing was measured experimentally by comparing the damage in the X-ray-irradiated regions of the submicrometre focus with the large-beam case under conditions of equal exposure and equal volumes of the protein crystal, and a mitigation factor of 4.4 ± 0.4 was determined. The mitigation of radiation damage is caused by spatial separation of the dominant PE radiation-damage component from the crystal region of the line-focus beam that contributes the diffraction signal. The diffraction signal is generated by coherent scattering of incident X-rays (which introduces no damage), while the overwhelming proportion of damage is caused by PE emission as X-ray photons are absorbed.

Metrology measurements for large-aperture VPH gratings

NASA Astrophysics Data System (ADS)

Zheng, Jessica R.; Gers, Luke; Heijmans, Jeroen

2013-09-01

The High Efficiency and Resolution Multi Element Spectrograph (HERMES) for the Australian Astronomical Observatory (AAO) uses four large aperture, high angle of incidence volume phase holographic gratings (VPHG) for high resolution `Galactic archaeology' spectroscopy. The large clear aperture, the high diffraction efficiency, the line frequency homogeneity, and mosaic alignment made manufacturing and testing challenging. We developed new metrology systems at the AAO to verify the performance of these VPH gratings. The measured diffraction efficiencies and line frequency of the VPH gratings received so far meet the vendor's provided data. The wavefront quality for the Blue VPH grating is good but the Green and Red VPH gratings need to be post polishing.

Performance of multilayer coated diffraction gratings in the EUV

NASA Technical Reports Server (NTRS)

Keski-Kuha, Ritva A. M.; Thomas, Roger J.; Gum, Jeffrey S.; Condor, Charles E.

1990-01-01

The effect of multilayer coating application on the performance of a diffraction grating in the EUV spectral region was evaluated by examining the performance of a 3600-line/mm and a 1200-line/mm replica blazed gratings, designed for operation in the 300-A spectral region in first order. A ten-layer IrSi multilayer optimized for 304 A was deposited using electron-beam evaporation. The grating efficiency was measured on the SURF II calibration beamline in a chamber designed for calibrating the solar EUV rocket telescope and spectrograph multilayer coatings. A significant (by a factor of about 7) enhancement in grating efficiency in the 300-A region was demonstrated.

An in-depth analysis and modelling of the Shuttle to MILA S-band telemetry link

NASA Technical Reports Server (NTRS)

Caroglanian, Armen; Pellerano, Fernando A.; Shama, Dale D.

1993-01-01

The S-Band radio frequency (RF) link between the Merritt Island (MILA) Tracking Station and the Space Shuttle launch pads is a critical communication path for prelaunch and launch operations. The proposed siting of the Center for Space Education (CSE) at the Visitor Center required a study to avoid RF line-of-sight blockage and reflection paths. The study revealed the trees near MILA's 9-meter (9-M) antennas are obstructing the optical line-of-sight. The studies found diffraction is the main propagation mechanism. This paper describes a link model based on the Geometric Theory of Diffraction.

Synchrotron radiation calibration of the EUVE variable line-spaced diffraction gratings at the NBS SURF II facility

NASA Technical Reports Server (NTRS)

Jelinsky, P.; Jelinsky, S. R.; Miller, A.; Vallerga, J.; Malina, R. F.

1988-01-01

The Extreme Ultraviolet Explorer (EUVE) has a spectrometer which utilizes variable line-spaced, plane diffraction gratings in the converging beam of a Wolter-Schwarzschild type II mirror. The gratings, microchannel plate detector, and thin film filters have been calibrated with continuum radiation provided by the NBS SURF II facility. These were calibrated in a continuum beam to find edges or other sharp spectral features in the transmission of the filters, quantum efficiency of the microchannel plate detector, and efficiency of the gratings. The details of the calibration procedure and the results of the calibration are presented.

Development of splitting convergent beam electron diffraction (SCBED).

PubMed

Houdellier, Florent; Röder, Falk; Snoeck, Etienne

2015-12-01

Using a combination of condenser electrostatic biprism with dedicated electron optic conditions for sample illumination, we were able to split a convergent beam electron probe focused on the sample in two half focused probes without introducing any tilt between them. As a consequence, a combined convergent beam electron diffraction pattern is obtained in the back focal plane of the objective lens arising from two different sample areas, which could be analyzed in a single pattern. This splitting convergent beam electron diffraction (SCBED) pattern has been tested first on a well-characterized test sample of Si/SiGe multilayers epitaxially grown on a Si substrate. The SCBED pattern contains information from the strained area, which exhibits HOLZ lines broadening induced by surface relaxation, with fine HOLZ lines observed in the unstrained reference part of the sample. These patterns have been analyzed quantitatively using both parts of the SCBED transmitted disk. The fine HOLZ line positions are used to determine the precise acceleration voltage of the microscope while the perturbed HOLZ rocking curves in the stained area are compared to dynamical simulated ones. The combination of these two information leads to a precise evaluation of the sample strain state. Finally, several SCBED setups are proposed to tackle fundamental physics questions as well as applied materials science ones and demonstrate how SCBED has the potential to greatly expand the range of applications of electron diffraction and electron holography. Copyright © 2015 Elsevier B.V. All rights reserved.

Molecular Switch for Sub-Diffraction Laser Lithography by Photoenol Intermediate-State Cis-Trans Isomerization.

PubMed

Mueller, Patrick; Zieger, Markus M; Richter, Benjamin; Quick, Alexander S; Fischer, Joachim; Mueller, Jonathan B; Zhou, Lu; Nienhaus, Gerd Ulrich; Bastmeyer, Martin; Barner-Kowollik, Christopher; Wegener, Martin

2017-06-27

Recent developments in stimulated-emission depletion (STED) microscopy have led to a step change in the achievable resolution and allowed breaking the diffraction limit by large factors. The core principle is based on a reversible molecular switch, allowing for light-triggered activation and deactivation in combination with a laser focus that incorporates a point or line of zero intensity. In the past years, the concept has been transferred from microscopy to maskless laser lithography, namely direct laser writing (DLW), in order to overcome the diffraction limit for optical lithography. Herein, we propose and experimentally introduce a system that realizes such a molecular switch for lithography. Specifically, the population of intermediate-state photoenol isomers of α-methyl benzaldehydes generated by two-photon absorption at 700 nm fundamental wavelength can be reversibly depleted by simultaneous irradiation at 440 nm, suppressing the subsequent Diels-Alder cycloaddition reaction which constitutes the chemical core of the writing process. We demonstrate the potential of the proposed mechanism for STED-inspired DLW by covalently functionalizing the surface of glass substrates via the photoenol-driven STED-inspired process exploiting reversible photoenol activation with a polymerization initiator. Subsequently, macromolecules are grown from the functionalized areas and the spatially coded glass slides are characterized by atomic-force microscopy. Our approach allows lines with a full-width-at-half-maximum of down to 60 nm and line gratings with a lateral resolution of 100 nm to be written, both surpassing the diffraction limit.

Constraining the geometry and kinematics of the quasar broad emission line region using gravitational microlensing. I. Models and simulations

NASA Astrophysics Data System (ADS)

Braibant, L.; Hutsemékers, D.; Sluse, D.; Goosmann, R.

2017-11-01

Recent studies have shown that line profile distortions are commonly observed in gravitationally lensed quasar spectra. Often attributed to microlensing differential magnification, line profile distortions can provide information on the geometry and kinematics of the broad emission line region (BLR) in quasars. We investigate the effect of gravitational microlensing on quasar broad emission line profiles and their underlying continuum, combining the emission from simple representative BLR models with generic microlensing magnification maps. Specifically, we considered Keplerian disk, polar, and equatorial wind BLR models of various sizes. The effect of microlensing has been quantified with four observables: μBLR, the total magnification of the broad emission line; μcont, the magnification of the underlying continuum; as well as red/blue, RBI and wings/core, WCI, indices that characterize the line profile distortions. The simulations showed that distortions of line profiles, such as those recently observed in lensed quasars, can indeed be reproduced and attributed to the differential effect of microlensing on spatially separated regions of the BLR. While the magnification of the emission line μBLR sets an upper limit on the BLR size and, similarly, the magnification of the continuum μcont sets an upper limit on the size of the continuum source, the line profile distortions mainly depend on the BLR geometry and kinematics. We thus built (WCI,RBI) diagrams that can serve as diagnostic diagrams to discriminate between the various BLR models on the basis of quantitative measurements. It appears that a strong microlensing effect puts important constraints on the size of the BLR and on its distance to the high-magnification caustic. In that case, BLR models with different geometries and kinematics are more prone to produce distinctive line profile distortions for a limited number of caustic configurations, which facilitates their discrimination. When the microlensing effect is weak, there is a larger overlap between the characteristics of the line profile distortions produced by the different models, and constraints can only be derived on a statistical basis.

Transmission-line model to design matching stage for light coupling into two-dimensional photonic crystals.

PubMed

Miri, Mehdi; Khavasi, Amin; Mehrany, Khashayar; Rashidian, Bizhan

2010-01-15

The transmission-line analogy of the planar electromagnetic reflection problem is exploited to obtain a transmission-line model that can be used to design effective, robust, and wideband interference-based matching stages. The proposed model based on a new definition for a scalar impedance is obtained by using the reflection coefficient of the zeroth-order diffracted plane wave outside the photonic crystal. It is shown to be accurate for in-band applications, where the normalized frequency is low enough to ensure that the zeroth-order diffracted plane wave is the most important factor in determining the overall reflection. The frequency limitation of employing the proposed approach is explored, highly dispersive photonic crystals are considered, and wideband matching stages based on binomial impedance transformers are designed to work at the first two photonic bands.

Statistical Nature of Atomic Disorder in Irradiated Crystals.

PubMed

Boulle, A; Debelle, A

2016-06-17

Atomic disorder in irradiated materials is investigated by means of x-ray diffraction, using cubic SiC single crystals as a model material. It is shown that, besides the determination of depth-resolved strain and damage profiles, x-ray diffraction can be efficiently used to determine the probability density function (PDF) of the atomic displacements within the crystal. This task is achieved by analyzing the diffraction-order dependence of the damage profiles. We thereby demonstrate that atomic displacements undergo Lévy flights, with a displacement PDF exhibiting heavy tails [with a tail index in the γ=0.73-0.37 range, i.e., far from the commonly assumed Gaussian case (γ=2)]. It is further demonstrated that these heavy tails are crucial to account for the amorphization kinetics in SiC. From the retrieved displacement PDFs we introduce a dimensionless parameter f_{D}^{XRD} to quantify the disordering. f_{D}^{XRD} is found to be consistent with both independent measurements using ion channeling and with molecular dynamics calculations.

Statistical Nature of Atomic Disorder in Irradiated Crystals

NASA Astrophysics Data System (ADS)

Boulle, A.; Debelle, A.

2016-06-01

Atomic disorder in irradiated materials is investigated by means of x-ray diffraction, using cubic SiC single crystals as a model material. It is shown that, besides the determination of depth-resolved strain and damage profiles, x-ray diffraction can be efficiently used to determine the probability density function (PDF) of the atomic displacements within the crystal. This task is achieved by analyzing the diffraction-order dependence of the damage profiles. We thereby demonstrate that atomic displacements undergo Lévy flights, with a displacement PDF exhibiting heavy tails [with a tail index in the γ =0.73 - 0.37 range, i.e., far from the commonly assumed Gaussian case (γ =2 )]. It is further demonstrated that these heavy tails are crucial to account for the amorphization kinetics in SiC. From the retrieved displacement PDFs we introduce a dimensionless parameter fDXRD to quantify the disordering. fDXRD is found to be consistent with both independent measurements using ion channeling and with molecular dynamics calculations.

Method and system for homogenizing diode laser pump arrays

DOEpatents

Bayramian, Andrew James

2016-05-03

An optical amplifier system includes a diode pump array including a plurality of semiconductor diode laser bars disposed in an array configuration and characterized by a periodic distance between adjacent semiconductor diode laser bars. The periodic distance is measured in a first direction perpendicular to each of the plurality of semiconductor diode laser bars. The diode pump array provides a pump output propagating along an optical path and characterized by a first intensity profile measured as a function of the first direction and having a variation greater than 10%. The optical amplifier system also includes a diffractive optic disposed along the optical path. The diffractive optic includes a photo-thermo-refractive glass member. The optical amplifier system further includes an amplifier slab having an input face and position along the optical path and separated from the diffractive optic by a predetermined distance. A second intensity profile measured at the input face of the amplifier slab as a function of the first direction has a variation less than 10%.

Method and system for homogenizing diode laser pump arrays

DOEpatents

Bayramian, Andy J

2013-10-01

An optical amplifier system includes a diode pump array including a plurality of semiconductor diode laser bars disposed in an array configuration and characterized by a periodic distance between adjacent semiconductor diode laser bars. The periodic distance is measured in a first direction perpendicular to each of the plurality of semiconductor diode laser bars. The diode pump array provides a pump output propagating along an optical path and characterized by a first intensity profile measured as a function of the first direction and having a variation greater than 10%. The optical amplifier system also includes a diffractive optic disposed along the optical path. The diffractive optic includes a photo-thermo-refractive glass member. The optical amplifier system further includes an amplifier slab having an input face and position along the optical path and separated from the diffractive optic by a predetermined distance. A second intensity profile measured at the input face of the amplifier slab as a function of the first direction has a variation less than 10%.

Diffraction-based overlay measurement on dedicated mark using rigorous modeling method

NASA Astrophysics Data System (ADS)

Lu, Hailiang; Wang, Fan; Zhang, Qingyun; Chen, Yonghui; Zhou, Chang

2012-03-01

Diffraction Based Overlay (DBO) is widely evaluated by numerous authors, results show DBO can provide better performance than Imaging Based Overlay (IBO). However, DBO has its own problems. As well known, Modeling based DBO (mDBO) faces challenges of low measurement sensitivity and crosstalk between various structure parameters, which may result in poor accuracy and precision. Meanwhile, main obstacle encountered by empirical DBO (eDBO) is that a few pads must be employed to gain sufficient information on overlay-induced diffraction signature variations, which consumes more wafer space and costs more measuring time. Also, eDBO may suffer from mark profile asymmetry caused by processes. In this paper, we propose an alternative DBO technology that employs a dedicated overlay mark and takes a rigorous modeling approach. This technology needs only two or three pads for each direction, which is economic and time saving. While overlay measurement error induced by mark profile asymmetry being reduced, this technology is expected to be as accurate and precise as scatterometry technologies.

Spectral shapes of rovibrational lines of CO broadened by He, Ar, Kr and SF6: A test case of the Hartmann-Tran profile

NASA Astrophysics Data System (ADS)

Ngo, N. H.; Lin, H.; Hodges, J. T.; Tran, H.

2017-12-01

High signal-to-noise ratio spectra of the (3-0) band P(1) and P(17) lines of CO broadened by He, Ar, Kr and SF6 were measured with a frequency-stabilized cavity ring-down spectroscopy system. For each collision-partner and both lines, multiple spectra were measured over pressures spanning nearly three decades up to 130 kPa. These data were analyzed with a multispectrum fitting procedure. Line shapes were modeled using the Hartmann-Tran (HT) profile with first-order line mixing as well as several other simplified profiles. The results show that for all considered collision partners (with the exception of SF6), the HT profile captures the measured line shapes with maximum absolute residuals that are within 0.1% of the peak absorption. In the case of SF6, which is the heaviest perturber investigated here, the maximum residuals for the HT profile are twice as large as for the other collision partners.

A high resolution spectroscopic study of the oxygen molecule. Ph.D. Thesis Final Report

NASA Technical Reports Server (NTRS)

Ritter, K. J.

1984-01-01

A high resolution spectrometer which incorporates a narrow line width tunable dye laser was used to make absorption profiles of 57 spectral lines in the Oxygen A-Band at pressures up to one atmosphere in pure O2. The observed line profiles are compared to the Voigt, and a collisionally narrowed, profile using a least squares fitting procedure. The collisionally narrowed profile compares more favorable to the observed profiles. Values of the line strengths and self broadening coeffiencients, determined from the least square fitting process, are presented in tabular form. It is found that the experssion by Watson are in closest agreement with the experimentally determined strengths. The self broadening coefficients are compared with the measurements of several other investigators.

Electromagnetic response of the protective pellicle of Euglenoids: influence of the surface profile

NASA Astrophysics Data System (ADS)

Inchaussandague, Marina E.; Gigli, Miriam L.; Skigin, Diana C.; Tolivia, Analía.; Conforti, Visitación

2015-03-01

In a recent paper we have investigated, from an electromagnetic point of view, the role played by the pellicle of Euglenoids -unicellular aquatic organisms- in the protection of the cell against UV radiation.14 By modelling the pellicle as a diffraction grating, we computed the electromagnetic response of different species that exhibit different behaviors against UV radiation. In this previous study, the pellicle profile was approximated by a sinusoidal grating. However, it has been observed in the transversal cut images that the profiles are not exactly sinusoidal, and also vary from sample to sample. Since the electromagnetic response depends on the geometry of the grating, reflectance calculations that take into account a more accurate representation of the actual profile could provide more insight into this problem. In this paper we investigate the electromagnetic response of the pellicle of Euglenoids for different grating profiles. The diffraction problem is solved by using the Chandezon method, which has demonstrated a successful performance for deep gratings of arbitrary profiles. We analyze the influence of the shape, depth and period of the grating on the UV reflectance. We show that the pellicle characteristics are critical parameters to increase the reflectance, thus reducing the penetration of the UV radiation within the cell and therefore, minimizing the damage and increasing the survival of these organisms.

Synthesis and characterization of Mn-Bi alloy

NASA Astrophysics Data System (ADS)

Mishra, Ashutosh; Patil, Harsha; Jain, G.; Mishra, N.

2012-06-01

High purity MnBi low temperature phase has been prepared and analyzed using X-ray diffraction, Lorentz-Polarization Factor and Fourier transforms infrared measurement. After synthesis of samples structural characterization has done on samples by X-ray diffraction, which shows that after making the bulk sample is in no single phase MnBi has been prepared by sintering Mn and Bi powders. By Lorentz-Polarization Factor is affecting the relative intensity of diffraction lines on a powder form. And by FTIR which shows absorption peaks of MnBi alloys.

Line Profile of H Lyman-Beta Emission from Dissociative Excitation of H2

NASA Technical Reports Server (NTRS)

Ajello, Joseph M.; Ahmed, Syed M.; Liu, Xian-Ming

1996-01-01

A high-resolution ultraviolet spectrometer was employed for a measurement of the H Lyman-Beta(H L(sub Beta)) emission Doppler line profile at 1025.7 A from dissociative excitation of H2 by electron impact. Analysis of the deconvolved line profile reveals the existence of a narrow central peak, less than 30 mA full width at half maximum (FWHM), and a broad pedestal base about 260 mA FWHM. Analysis of the red wing of the line profile is complicated by a group of Wemer and Lyman rotational lines 160-220 mA from the line center. Analysis of the blue wing of the line profile gives the kinetic-energy distribution. There are two main kinetic-energy components to the H(3p) distribution: (1) a slow distribution with a peak value near 0 eV from singly excited states, and (2) a fast distribution with a peak contribution near 7 eV from doubly excited states. Using two different techniques, the absolute cross section of H L(sub Beta)p is found to be 3.2+/-.8 x 10(exp -19)sq cm at 100-eV electron impact energy. The experimental cross-section and line-profile results can be compared to previous studies of H(alpha) (6563.7 A) for principal quantum number n=3 and L(sub alpha)(1215.7 A) for n=2.

Goddard High Resolution Spectrograph Observations of Variability in the RS Canum Venaticorum System V711 Tauri (HR 1099)

NASA Technical Reports Server (NTRS)

Dempsey, Robert C.; Neff, James E.; Thorpe, Marjorie J.; Linsky, Jeffrey L.; Brown, Alexander; Cutispoto, Giuseppe; Rodono, Marcello

1996-01-01

Goddard High Resolution Spectrograph (GHRS) observations of the RS CVn-type binary V711 Tau (Kl IV+G5 IV) were obtained at several phases over two consecutive stellar orbital cycles in order to study ultraviolet emission-line profile and flux variability. Spectra cover the Mg II h and k lines, C IV doublet, and Si IV region, as well as the density-sensitive lines of C III] (1909 A) and Si III] (1892 A). IUE spectra, Extreme Ultra Violet (EUV) data, and Ultraviolet, Blue, Visual (UBV) photometry were obtained contemporaneously with the GHRS data. Variable extended wings were detected in the Mg II lines. We discuss the Mg II line profile variability using various Gaussian emission profile models. No rotational modulation of the line profiles was observed, but there were several large flares. These flares produced enhanced emission in the extended line wings, radial velocity shifts, and asymmetries in some line profiles. Nearly continuous flaring for more than 24 hr, as indicated in the IUE data, represents the most energetic and long-lived chromospheric and transition region flare ever observed with a total energy much greater than 5 x 10(exp 35) ergs. The C III] to Si III] line ratio is used to estimate the plasma density during the flares.

What Sets the Line Profiles in Tidal Disruption Events?

NASA Astrophysics Data System (ADS)

Roth, Nathaniel; Kasen, Daniel

2018-03-01

We investigate line formation in gas that is outflowing and optically thick to electron scattering, as may be expected following the tidal disruption of a star by a supermassive black hole. Using radiative transfer calculations, we show that the optical line profiles produced by expanding TDE outflows most likely are primarily emission features, rather than the P-Cygni profiles seen in most supernova spectra. This is a result of the high line excitation temperatures in the highly irradiated TDE gas. The outflow kinematics cause the emission peak to be blueshifted and have an asymmetric red wing. Such features have been observed in some TDE spectra, and we propose that these may be signatures of outflows. We also show that non-coherent scattering of hot electrons can broaden the emission lines by ∼10,000 km s‑1, such that the line width in some TDEs may be set by the electron scattering optical depth rather than the gas kinematics. The scattering-broadened line profiles produce distinct, wing-shaped profiles that are similar to those observed in some TDE spectra. The narrowing of the emission lines over time in these observed events may be related to a drop in density rather than a drop in line-of-sight velocity.

Integrated high-order surface diffraction gratings for diode lasers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zolotarev, V V; Leshko, A Yu; Pikhtin, N A

2015-12-31

High-order surface diffraction gratings acting as a distributed Bragg reflector (DBR) in mesa stripe semiconductor lasers (λ = 1030 nm) have been studied theoretically and experimentally. Higher order interfering radiation modes (IRMs), which propagate off the plane of the waveguide, have been shown to have a crucial effect on the reflection and transmission spectra of the DBR. The decrease in the reflectivity of the DBR in response to the increase in the diffraction efficiency of these modes may reach 80% and more. According to theoretical analysis results, the intensity of the higher order IRMs is determined by the geometry ofmore » the DBR groove profile. Experimental data demonstrate that the noncavity modes are responsible for parasitic light leakage losses in the laser cavity. It has been shown that, in the case of nonoptimal geometry of the grating groove profile, the overall external differential quantum efficiency of the parasitic laser emission may exceed 45%, which is more than half of the laser output power. The optimal geometry of the DBR groove profile is trapezoidal, with the smallest possible lower base. Experimental evidence has been presented that this geometry considerably reduces the power of the higher order IRMs and minimises the parasitic light leakage loss. (lasers)« less

Diffraction efficiency of radially-profiled off-plane reflection gratings

NASA Astrophysics Data System (ADS)

Miles, Drew M.; Tutt, James H.; DeRoo, Casey T.; Marlowe, Hannah; Peterson, Thomas J.; McEntaffer, Randall L.; Menz, Benedikt; Burwitz, Vadim; Hartner, Gisela; Laubis, Christian; Scholze, Frank

2015-09-01

Future X-ray missions will require gratings with high throughput and high spectral resolution. Blazed off-plane reflection gratings are capable of meeting these demands. A blazed grating profile optimizes grating efficiency, providing higher throughput to one side of zero-order on the arc of diffraction. This paper presents efficiency measurements made in the 0.3 - 1.5 keV energy band at the Physikalisch-Technische Bundesanstalt (PTB) BESSY II facility for three holographically-ruled gratings, two of which are blazed. Each blazed grating was tested in both the Littrow configuration and anti-Littrow configuration in order to test the alignment sensitivity of these gratings with regard to throughput. This paper outlines the procedure of the grating experiment performed at BESSY II and discuss the resulting efficiency measurements across various energies. Experimental results are generally consistent with theory and demonstrate that the blaze does increase throughput to one side of zero-order. However, the total efficiency of the non-blazed, sinusoidal grating is greater than that of the blazed gratings, which suggests that the method of manufacturing these blazed profiles fails to produce facets with the desired level of precision. Finally, evidence of a successful blaze implementation from first diffraction results of prototype blazed gratings produce via a new fabrication technique at the University of Iowa are presented.

Stratospheric sounding by infrared heterodyne spectroscopy

NASA Technical Reports Server (NTRS)

Abbas, M. M.; Kunde, V. G.; Mumma, M. J.; Kostiuk, T.; Buhl, D.; Frerking, M. A.

1978-01-01

Intensity profiles of infrared spectral lines of stratospheric constituents can be fully resolved with a heterodyne spectrometer of sufficiently high resolution. The constituents' vertical distributions can then be evaluated accurately by analytic inversion of the measured line profiles. Estimates of the detection sensitivity of a heterodyne receiver are given in terms of minimum detectable volume mixing ratios of stratospheric constituents, indicating a large number of minor constituents which can be studied. Stratospheric spectral line shapes, and the resolution required to measure them are discussed in light of calculated synthetic line profiles for some stratospheric molecules in a model atmosphere. The inversion technique for evaluation of gas concentration profiles is briefly described and applications to synthetic lines of O3, CO2, CH4 and N2O are given.

STELLAR SURFACE MAGNETO-CONVECTION AS A SOURCE OF ASTROPHYSICAL NOISE. I. MULTI-COMPONENT PARAMETERIZATION OF ABSORPTION LINE PROFILES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cegla, H. M.; Shelyag, S.; Watson, C. A.

2013-02-15

We outline our techniques to characterize photospheric granulation as an astrophysical noise source. A four-component parameterization of granulation is developed that can be used to reconstruct stellar line asymmetries and radial velocity shifts due to photospheric convective motions. The four components are made up of absorption line profiles calculated for granules, magnetic intergranular lanes, non-magnetic intergranular lanes, and magnetic bright points at disk center. These components are constructed by averaging Fe I 6302 A magnetically sensitive absorption line profiles output from detailed radiative transport calculations of the solar photosphere. Each of the four categories adopted is based on magnetic fieldmore » and continuum intensity limits determined from examining three-dimensional magnetohydrodynamic simulations with an average magnetic flux of 200 G. Using these four-component line profiles we accurately reconstruct granulation profiles, produced from modeling 12 Multiplication-Sign 12 Mm{sup 2} areas on the solar surface, to within {approx} {+-}20 cm s{sup -1} on a {approx}100 m s{sup -1} granulation signal. We have also successfully reconstructed granulation profiles from a 50 G simulation using the parameterized line profiles from the 200 G average magnetic field simulation. This test demonstrates applicability of the characterization to a range of magnetic stellar activity levels.« less

PRESSURE SHIFT AND GRAVITATIONAL REDSHIFT OF BALMER LINES IN WHITE DWARFS: REDISCUSSION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Halenka, Jacek; Olchawa, Wieslaw; Madej, Jerzy

2015-08-01

The Stark-induced shift and asymmetry, the so-called pressure shift (PS) of H{sub α} and H{sub β} Balmer lines in spectra of DA white dwarfs (WDs), have been examined in detail as masking effects in measurements of the gravitational redshift in WDs. The results are compared with our earlier ones from a quarter of a century ago. In these earlier papers, the standard, symmetrical Stark line profiles, as a dominant constituent of the Balmer line profiles but shifted as a whole by the PS effect, were applied to all spectrally active layers of the WD atmosphere. At present, in each ofmore » the WD layers, the Stark line profiles (especially of H{sub β}) are inherently asymmetrical and shifted due to the effects of strong inhomogeneity of the perturbing fields in plasma. To calculate the Stark line profiles in successive layers of the WD atmosphere we used the modified Full Computer Simulation Method, able to take adequately into account the complexity of local elementary quantum processes in plasma. In the case of the H{sub α} line, the present value of Stark-induced shift of the synthetic H{sub α} line profile is about half the previous one and it is negligible in comparison with the gravitational redshift. In the case of the H{sub β} line, the present value of Stark-induced shift of the synthetic H{sub β} line profile is about twice the previous one. The source of this extra shift is the asymmetry of H{sub β} peaks.« less

The homogeneity effect on figure/ground perception in infancy.

PubMed

Takashima, Midori; Kanazawa, So; Yamaguchi, Masami K; Shiina, Ken

2014-02-01

We examined whether the homogeneity of the two profiles of Rubin's goblet affects figure/ground perception in infants. We modified the two profiles of Rubin's goblet in order to compare figure/ground perception under four test patterns: (1) two profiles painted with horizontal lines (horizontal-line condition), (2) two profiles painted middle gray (uni-color condition), (3) one profile painted light gray and the other dark gray (two-color condition), and (4) a goblet painted with concentric circles (concentric-circles condition). In the horizontal-line condition the homogeneity of the profile was strengthened, and in the two-color condition the homogeneity of the profile was weakened compared to the uni-color condition, which was an original Rubin's goblet. In the concentric-circles condition the homogeneity of the reversed areas of the horizontal-line were strengthened. After infants were familiarized with each Rubin's goblet, the infants were tested on their discrimination between the two profiles and the goblet in the post-familiarization test. In horizontal-line condition, uni-color condition and concentric-circles condition infants showed a novelty preference for the two profiles in the post-familiarization test. On the other hand, in the two-color condition no preference was observed in the post-familiarization test. This means that infants perceived the goblet as figure and the two profiles as ground in the horizontal-line condition, the uni-color condition and the concentric-circles condition. We found that infants could not perceive the goblet area as figure when the homogeneity of the two profiles was weakened. It can be said that figure/ground perception in infancy is not affected by strengthened homogeneity, but is affected by weakened homogeneity. Copyright © 2014 Elsevier Inc. All rights reserved.

Random sampling technique for ultra-fast computations of molecular opacities for exoplanet atmospheres

NASA Astrophysics Data System (ADS)

Min, M.

2017-10-01

Context. Opacities of molecules in exoplanet atmospheres rely on increasingly detailed line-lists for these molecules. The line lists available today contain for many species up to several billions of lines. Computation of the spectral line profile created by pressure and temperature broadening, the Voigt profile, of all of these lines is becoming a computational challenge. Aims: We aim to create a method to compute the Voigt profile in a way that automatically focusses the computation time into the strongest lines, while still maintaining the continuum contribution of the high number of weaker lines. Methods: Here, we outline a statistical line sampling technique that samples the Voigt profile quickly and with high accuracy. The number of samples is adjusted to the strength of the line and the local spectral line density. This automatically provides high accuracy line shapes for strong lines or lines that are spectrally isolated. The line sampling technique automatically preserves the integrated line opacity for all lines, thereby also providing the continuum opacity created by the large number of weak lines at very low computational cost. Results: The line sampling technique is tested for accuracy when computing line spectra and correlated-k tables. Extremely fast computations ( 3.5 × 105 lines per second per core on a standard current day desktop computer) with high accuracy (≤1% almost everywhere) are obtained. A detailed recipe on how to perform the computations is given.

Automated Micro-Object Detection for Mobile Diagnostics Using Lens-Free Imaging Technology

PubMed Central

Roy, Mohendra; Seo, Dongmin; Oh, Sangwoo; Chae, Yeonghun; Nam, Myung-Hyun; Seo, Sungkyu

2016-01-01

Lens-free imaging technology has been extensively used recently for microparticle and biological cell analysis because of its high throughput, low cost, and simple and compact arrangement. However, this technology still lacks a dedicated and automated detection system. In this paper, we describe a custom-developed automated micro-object detection method for a lens-free imaging system. In our previous work (Roy et al.), we developed a lens-free imaging system using low-cost components. This system was used to generate and capture the diffraction patterns of micro-objects and a global threshold was used to locate the diffraction patterns. In this work we used the same setup to develop an improved automated detection and analysis algorithm based on adaptive threshold and clustering of signals. For this purpose images from the lens-free system were then used to understand the features and characteristics of the diffraction patterns of several types of samples. On the basis of this information, we custom-developed an automated algorithm for the lens-free imaging system. Next, all the lens-free images were processed using this custom-developed automated algorithm. The performance of this approach was evaluated by comparing the counting results with standard optical microscope results. We evaluated the counting results for polystyrene microbeads, red blood cells, HepG2, HeLa, and MCF7 cells lines. The comparison shows good agreement between the systems, with a correlation coefficient of 0.91 and linearity slope of 0.877. We also evaluated the automated size profiles of the microparticle samples. This Wi-Fi-enabled lens-free imaging system, along with the dedicated software, possesses great potential for telemedicine applications in resource-limited settings. PMID:27164146

A novel optical imaging system for investigating sarcomere dynamics in single skeletal muscle fibers

NASA Astrophysics Data System (ADS)

Panchangam, Appaji; Witte, Russell S.; Claflin, Dennis R.; O'Donnell, Matthew; Faulkner, John A.

2006-02-01

The protein substructure of skeletal muscle fibers forms a diffraction grating with repeating units, termed 'sarcomeres'. A laser scanning system is described that maps the lengths of sarcomeres (SL) and the widths of the first-order diffraction lines (DLW) of permeabilized single fibers in real-time. The apparatus translates a laser beam (λ = 670 nm and w 0 = ~75 μm) along the length of a fiber segment through 20 contiguous regions per sweep at 500 sweeps/s. The fiber segments (~1 mm long) were obtained from vastus lateralis muscles of humans by needle biopsy. During both passive stretches and maximum fixed-end activations, the mappings of SL and DLW of the fibers were extracted from the diffraction spectra. Heterogeneity of SLs was evaluated by computing the standard deviation ( σ SL) of the 20 SLs measured during a single sweep. Compared with the σ SL before a passive stretch, the increase of 5+/-0.5% in σ SL after the passive stretch, indicated differences in passive length-tension relationships along the fiber. In contrast, no change, ~0.5+/-0.1%, was observed in DLW. Within 10s after the fiber was returned to its initial length, the shape of the SL profile returned close to pre-stretch conditions ( σ SL = 1+/- 0.2%). Following maximum Ca 2+ - activation of the fiber, the heterogeneity of the steady state SLs increased greatly (DLW up by ~300% and σ SL up by ~100%). The scanning system provided high resolution tracking of sarcomere behavior single muscle fibers. Potential applications are for studies of the mechanisms of muscle fiber injury and injury propagation.

Measuring the x-ray resolving power of bent potassium acid phthalate diffraction crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haugh, M. J., E-mail: haughmj@nv.doe.gov; Jacoby, K. D.; Wu, M.

2014-11-15

This report presents the results from measuring the X-ray resolving power of a curved potassium acid phthalate (KAP(001)) spectrometer crystal using two independent methods. It is part of a continuing effort to measure the fundamental diffraction properties of bent crystals that are used to study various characteristics of high temperature plasmas. Bent crystals like KAP(001) do not usually have the same diffraction properties as corresponding flat crystals. Models that do exist to calculate the effect of bending the crystal on the diffraction properties have simplifying assumptions and their accuracy limits have not been adequately determined. The type of crystals thatmore » we measured is being used in a spectrometer on the Z machine at Sandia National Laboratories in Albuquerque, New Mexico. The first technique for measuring the crystal resolving power measures the X-ray spectral line width of the characteristic lines from several metal anodes. The second method uses a diode X-ray source and a double crystal diffractometer arrangement to measure the reflectivity curve of the KAP(001) crystal. The width of that curve is inversely proportional to the crystal resolving power. The measurement results are analyzed and discussed.« less

Measuring the X-ray Resolving Power of Bent Potassium Acid Phthalate Diffraction Crystals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haugh, M. J.; Wu, M.; Jacoby, K. D.

2014-11-01

This report presents the results from measuring the X-ray resolving power of a curved potassium acid phthalate (KAP(001)) spectrometer crystal using two independent methods. It is part of a continuing effort to measure the fundamental diffraction properties of bent crystals that are used to study various characteristics of high temperature plasmas. Bent crystals like KAP(001) do not usually have the same diffraction properties as corresponding flat crystals. Models that do exist to calculate the effect of bending the crystal on the diffraction properties have simplifying assumptions and their accuracy limits have not been adequately determined. The type of crystals thatmore » we measured is being used in a spectrometer on the Z machine at Sandia National Laboratories (SNL) in Albuquerque, NM. The first technique for measuring the crystal resolving power measures the X-ray spectral line width of the characteristic lines from several metal anodes. The second method uses a diode X-ray source and a dual goniometer arrangement to measure the reflectivity curve of the KAP(001) crystal. The width of that curve is inversely proportional to the crystal resolving power. The measurement results are analyzed and discussed.« less

Measuring the x-ray resolving power of bent potassium acid phthalate diffraction crystalsa)

NASA Astrophysics Data System (ADS)

Haugh, M. J.; Wu, M.; Jacoby, K. D.; Loisel, G. P.

2014-11-01

This report presents the results from measuring the X-ray resolving power of a curved potassium acid phthalate (KAP(001)) spectrometer crystal using two independent methods. It is part of a continuing effort to measure the fundamental diffraction properties of bent crystals that are used to study various characteristics of high temperature plasmas. Bent crystals like KAP(001) do not usually have the same diffraction properties as corresponding flat crystals. Models that do exist to calculate the effect of bending the crystal on the diffraction properties have simplifying assumptions and their accuracy limits have not been adequately determined. The type of crystals that we measured is being used in a spectrometer on the Z machine at Sandia National Laboratories in Albuquerque, New Mexico. The first technique for measuring the crystal resolving power measures the X-ray spectral line width of the characteristic lines from several metal anodes. The second method uses a diode X-ray source and a double crystal diffractometer arrangement to measure the reflectivity curve of the KAP(001) crystal. The width of that curve is inversely proportional to the crystal resolving power. The measurement results are analyzed and discussed.

Design of a Binary Grating with Subwavelength Features that Acts as a Polarizing Beam Splitter.

PubMed

Pajewski, L; Borghi, R; Schettini, G; Frezza, F; Santarsiero, M

2001-11-10

A binary diffractive optical element, acting as a polarizing beam splitter, is proposed and analyzed. It behaves like a transmissive blazed grating, working on the first or the second diffraction order, depending on the polarization state of the incident radiation. The grating-phase profile required for both polarization states is obtained by means of suitably sized subwavelength groups etched in an isotropic dielectric medium. A rigorous electromagnetic analysis of the grating is presented, and numerical results concerning its performances in terms of diffraction efficiency as well as frequency and angular bandwidths are provided.

Logo recognition in video by line profile classification

NASA Astrophysics Data System (ADS)

den Hollander, Richard J. M.; Hanjalic, Alan

2003-12-01

We present an extension to earlier work on recognizing logos in video stills. The logo instances considered here are rigid planar objects observed at a distance in the scene, so the possible perspective transformation can be approximated by an affine transformation. For this reason we can classify the logos by matching (invariant) line profiles. We enhance our previous method by considering multiple line profiles instead of a single profile of the logo. The positions of the lines are based on maxima in the Hough transform space of the segmented logo foreground image. Experiments are performed on MPEG1 sport video sequences to show the performance of the proposed method.

A Si I atomic model for NLTE spectropolarimetric diagnostics of the 10 827 Å line

NASA Astrophysics Data System (ADS)

Shchukina, N. G.; Sukhorukov, A. V.; Trujillo Bueno, J.

2017-07-01

Aims: The Si I 10 827 Å line is commonly used for spectropolarimetric diagnostics of the solar atmosphere. First, we aim at quantifying the sensitivity of the Stokes profiles of this line to non-local thermodynamic equilibrium (NLTE) effects. Second, we aim at facilitating NLTE diagnostics of the Si I 10 827 Å line. To this end, we propose the use of a relatively simple silicon model atom, which allows a fast and accurate computation of Stokes profiles. The NLTE Stokes profiles calculated using this simple model atom are very similar to those obtained via the use of a very comprehensive silicon model atom. Methods: We investigate the impact of the NLTE effects on the Si I 10 827 Å line by means of multilevel radiative transfer calculations in a three-dimensional (3D) model atmosphere taken from a state-of-the-art magneto-convection simulation with small-scale dynamo action. We calculate the emergent Stokes profiles for this line at the solar disk center and for every vertical column of the 3D snapshot model, neglecting the effects of horizontal radiative transfer. Results: We find significant departures from LTE in the Si I 10 827 Å line, not only in the intensity but also in the linearly and circularly polarized profiles. At wavelengths around 0.1 Å, where most of the Stokes Q, U, and V peaks of the Si I 10 827 Å line occur, the differences between the NLTE and LTE profiles are comparable with the Stokes amplitudes themselves. The deviations from LTE increase with increasing Stokes Q, U, and V signals. Concerning the Stokes V profiles, the NLTE effects correlate with the magnetic field strength in the layers where such circular polarization signals are formed. Conclusions: The NLTE effects should be taken into account when diagnosing the emergent Stokes I profiles as well as the Stokes Q, U, and V profiles of the Si I 10 827 Å line. The sixteen-level silicon model atom proposed here, with six radiative bound-bound transitions, is suitable to account for the physics of formation of the Si I 10 827 Å line and for modeling and inverting its Stokes profiles without assuming LTE.

Theoretical model of a polarization diffractive elements for the light beams conversion holographic formation in PDLCs

NASA Astrophysics Data System (ADS)

Sharangovich, Sergey N.; Semkin, Artem O.

2017-12-01

In this work a theoretical model of the holographic formation of the polarization diffractive optical elements for the transformation of Gaussian light beams into Bessel-like ones in polymer-dispersed liquid crystals (PDLC) is developed. The model is based on solving the equations of photo-induced Fredericks transition processes for polarization diffractive elements formation by orthogonally polarized light beams with inhomogeneous amplitude and phase profiles. The results of numerical simulation of the material's dielectric tensor changing due to the structure's formation process are presented for various recording beams' polarization states. Based on the results of numerical simulation, the ability to form the diffractive optical elements for light beams transformation by the polarization holography methods is shown.

Diffractive beam shaping for enhanced laser polymer welding

NASA Astrophysics Data System (ADS)

Rauschenberger, J.; Vogler, D.; Raab, C.; Gubler, U.

2015-03-01

Laser welding of polymers increasingly finds application in a large number of industries such as medical technology, automotive, consumer electronics, textiles or packaging. More and more, it replaces other welding technologies for polymers, e. g. hot-plate, vibration or ultrasonic welding. At the same rate, demands on the quality of the weld, the flexibility of the production system and on processing speed have increased. Traditionally, diode lasers were employed for plastic welding with flat-top beam profiles. With the advent of fiber lasers with excellent beam quality, the possibility to modify and optimize the beam profile by beam-shaping elements has opened. Diffractive optical elements (DOE) can play a crucial role in optimizing the laser intensity profile towards the optimal M-shape beam for enhanced weld seam quality. We present results on significantly improved weld seam width constancy and enlarged process windows compared to Gaussian or flat-top beam profiles. Configurations in which the laser beam diameter and shape can be adapted and optimized without changing or aligning the laser, fiber-optic cable or optical head are shown.

Results of Detailed Modeling of the Narrow-Line Region of Seyfert Galaxies

NASA Technical Reports Server (NTRS)

Moore, David; Cohen, Ross D.

1996-01-01

We present model line profiles of [O II] lambda3727, [Ne III] lambda3869, [O I] lambda5007, [Fe VII] lambda6087, [Fe X] lambda6374, [O I] lambda6300, H(alpha) lambda6563, and [S 2] lambda6731. The profiles presented here illustrate explicitly the pronounced effects that collisional de-excitation, and that spatial variations in both the ionization parameter and cloud column density, have on Narrow-Line Region (NLR) model profiles. The above effects were included only qualitatively in a previous analytical treatment by Moore and Cohen. By making a direct correspondence between these model profiles and the analytical model profiles of Moore and Cohen, and by comparing with the observed profiles presented in a companion paper and also with those presented elsewhere in the literature, we strengthen some of the conclusions of Moore and Cohen. Most notably, we argue for constant ionization parameter, uniformly accelerated outflow of clouds that are individually stratified in ionization, and the interpretation of emission-line width correlations with ionization potential as a column density effect. For comparison with previous observational studies, such as our own in a companion paper, we also calculate profile parameters for some of the models, and we present and discuss the resulting line width correlations with critical density (n(sub cr)) and Ionization Potential (IP). Because the models we favor are those that produce extended profile wings as observed in high spectral resolution studies, the line width correlations of our favoured models are of particular interest. Line width correlations with n(sub cr) and/or IP result only if the width parameter is more sensitive to extended profile wings than is the Full Width at Half-Maximum (FWHM). Correlations between FWHM and n(sub cr) and/or IP result only after convolving the model profiles with a broad instrumental profile that simulates the lower spectral resolution used in early observational studies. The model in agreement with the greatest number of observational considerations has electron density decreasing outward from n(sub e) approx. equals 10(exp 6)/cu cm to n(sub e) approx. equals 10(exp 2)/cu cm and, due to collisional de-excitation effects in the lowest velocity clouds, it generates broad flat-topped profile peaks in the lines of lowest critical density (e.g., [O II] lambda3727 and [S II] lambda(lambda)6716, 6731). Because the observed profile peaks of both low and high critical density lines are often very similar, our favored model requires a contribution to NLR emission-line spectra from low-velocity, low-density, and low-ionization gas not included in the model NLR.

Fiber Optic Picosecond Laser Pulse Transmission Line for Hydrogen Ion Beam Profile Measurement

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Yun; Huang, Chunning; Aleksandrov, Alexander V

2013-01-01

We present a fiber optic laser pulse transmission line for non-intrusive longitudinal profile measurement of the hydrogen ion (H-) beam at the front-end of the Spallation Neutron Source (SNS) accelerator. The 80.5 MHz, 2.5 ps, multi-killowatt optical pulses are delivered to the accelerator beam line through a large mode area polarization maintaining optical fiber to ensure a high measurement stability. The transmission efficiency, output laser beam quality, pulse jitter and pulse width broadening over a 100-ft fiber line are experimentally investigated. A successful measurement of the H- beam microbunch (~130 ps) profile is obtained. Our experiment is the first demonstrationmore » of particle beam profile diagnostics using fiber optic laser pulse transmission line.« less

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

NASA Technical Reports Server (NTRS)

Wiedemann, K. E.; Unnam, J.

1984-01-01

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

Instrument and method for focusing x rays, gamma rays, and neutrons

DOEpatents

Smither, R.K.

1982-03-25

A crystal-diffraction instrument or diffraction-grating instrument is described with an improved crystalline structure or grating spacing structure having a face for receiving a beam of photons or neutrons and diffraction planar spacing or grating spacing along that face with the spacing increasing progressively along the face to provide a decreasing Bragg diffraction angle for a monochromatic radiation and thereby increasing the usable area and acceptance angle. The increased planar spacing for the diffraction crystal is provided by the use of a temperature differential across the line structures with different compositions, by an individual crystalline structure with a varying composition and thereby a changing planar spacing along its face, and by combinations of these techniques. The increased diffraction grating element spacing is generated during the fabrication of the diffraction grating by controlling the cutting tool that is cutting the grooves or controlling the laser beam, electron beam, or ion beam that is exposing the resist layer, etc. It is also possible to vary this variation in grating spacing by applying a thermal gradient to the diffraction grating in much the same manner as is done in the crystal-diffraction case.

Formation of mixed-layer structures in smectites intercalated with tryptone

NASA Astrophysics Data System (ADS)

Block, K. A.; Trusiak, A.; Steiner, J. C.; Katz, A.; Gottlieb, P.; Alimova, A.

2012-12-01

Stable clay-protein complexes are fundamental to studies of the critical zone, terrestrial ecosystems, pharmacology, and industrial applications such as bioremediation. Two sets of montmorillonite clays were purified and made homoionic for Na and Mg. Mg-montmorillonite and Na-montmorillonite were mixed with tryptone (casein digest) in a 9:1 and 18:1 clay:tryptone ratio, resulting in the formation of reversible intercalated structures. X-ray diffraction analysis of the protein-clay complexes produced profiles consisting of two peaks associated with the smectite 001 reflection and a related tryptone-packet peak similar to that produced by a mixed layer clay structure. Shifts in the 002, 003, and 004 diffraction maxima are attributed to disorder caused by the interaction with the protein. Line broadening in the smectite-tryptone XRD spectra is interpreted to be the result of interlayer absorption. Adsorption produces coherent crystalline packets of regularly interbedded tryptone and smectite platelets. SEM images reveal clay platelets with upwardly rolled edges that tend toward cylindrical structures with the production of occasional tubes in the smaller platelet size range as noted for organic compound-kaolinite intercalation reported by Fenoll Hach-Ali and Weiss (1969). Reference: Fenoll Hach-Ali, P.F., Weiss, A., 1969. Estudio de la reaccion de caolinita y N-metilform- amida. Quimica LXV, 769-790. Scanning electron micrograph of tryptone-intercalated clay platelets exhibiting rolled edge structure.

AGN Space Telescope and Optical Reverberation Mapping Project. IV. Velocity-Delay Mapping of Broad Emission Lines in NGC 5548

NASA Astrophysics Data System (ADS)

Horne, Keith D.; Agn Storm Team

2015-01-01

Two-dimensional velocity-delay maps of AGN broad emission line regions can be recovered by modelling observations of reverberating emission-line profiles on the assumption that the line profile variations are driven by changes in ionising radiation from a compact source near the black hole. The observable light travel time delay resolves spatial structure on iso-delay paraboloids, while the doppler shift resolves kinematic structure along the observer's line-of-sight. Velocity-delay maps will be presented and briefly discussed for the Lyman alpha, CIV and Hbeta line profiles based on the HST and ground-based spectrophotometric monitoring of NGC 5548 during the 2014 AGN STORM campaign.

Planar techniques for fabricating X-ray diffraction gratings and zone plates

NASA Technical Reports Server (NTRS)

Smith, H. I.; Anderson, E. H.; Hawryluk, A. M.; Schattenburg, M. L.

1984-01-01

The state of current planar techniques in the fabrication of Fresnel zone plates and diffraction gratings is reviewed. Among the fabrication techniques described are multilayer resist techniques; scanning electron beam lithography; and holographic lithography. Consideration is also given to: X-ray lithography; ion beam lithography; and electroplating. SEM photographs of the undercut profiles obtained in a type AZ 135OB photoresistor by holographic lithography are provided.

Neutron diffraction investigation of γ manganese hydride

NASA Astrophysics Data System (ADS)

Fedotov, V. K.; Antonov, V. E.; Kolesnikov, A. I.; Beskrovnyi, A. I.; Grosse, G.; Wagner, F. E.

1998-08-01

A profile analysis of the neutron diffraction spectrum of the fcc high pressure hydride λ-MnH 0.41 measured under ambient conditions showed that hydrogen is randomly distributed over the octahedral interstices of the fcc metal lattice and that the hydride is an antiferromagnet with the same collinear spin structure as pure λ-Mn, but with a smaller magnetic moment of about 1.9 Bohr magnetons per Mn atom.

Fourier analysis of He 4471/Mg 4481 line profiles for separating rotational velocity and axial inclination in rapidly rotating B-type stars

NASA Astrophysics Data System (ADS)

Takeda, Y.; Kawanomoto, S.; Ohishi, N.

2017-11-01

While the effect of rotation on spectral lines is complicated in rapidly rotating stars because of the appreciable gravity-darkening effect differing from line to line, it is possible to make use of this line-dependent complexity to separately determine the equatorial rotation velocity (ve) and the inclination angle (i) of rotational axis. Although linewidths of spectral lines were traditionally used for this aim, we tried in this study to apply the Fourier method, which utilizes the unambiguously determinable first-zero frequency (σ1) in the Fourier transform of line profile. Equipped with this technique, we analysed the profiles of He I 4471 and Mg I 4481 lines of six rapidly rotating (ve sin i ∼ 150-300 km s-1) late B-type stars, while comparing them with the theoretical profiles simulated on a grid of models computed for various combination of (ve, i). According to our calculation, σ1 tends to be larger than the classical value for given ve sin i. This excess progressively grows with an increase in ve, and is larger for the He line than the Mg line, which leads to {σ} 1^He > {σ} 1^Mg. It was shown that ve and i are separately determinable from the intersection of two loci (sets of solutions reproducing the observed σ1 for each line) on the ve versus i plane. Yet, line profiles alone are not sufficient for their unique discrimination, for which photometric information (such as colours) needs to be simultaneously employed.

Theory of time-resolved x-ray photoelectron diffraction from transient conformational molecules

NASA Astrophysics Data System (ADS)

Tsuru, Shota; Sako, Tokuei; Fujikawa, Takashi; Yagishita, Akira

2017-04-01

We formulate x-ray photoelectron diffraction (XPD) from molecules undergoing photochemical reactions induced by optical laser pulses, and then apply the formula to the simulation of time-dependent XPD profiles from both dissociating I2 molecules and bending C S2 molecules. The dependence of nuclear wave-packet motions on the intensity and shape of the optical laser pulses is examined. As a result, the XPD simulations based on such nuclear wave-packet calculations are observed to exhibit characteristic features, which are compared with the XPD profiles due to classical trajectories of nuclear motions. The present study provides a methodology toward creating "molecular movies" of ultrafast photochemical reactions by means of femtosecond XPD with x-ray free-electron lasers.

Scatterometry—fast and robust measurements of nano-textured surfaces

NASA Astrophysics Data System (ADS)

Hannibal Madsen, Morten; Hansen, Poul-Erik

2016-06-01

Scatterometry is a fast, precise and low cost way to determine the mean pitch and dimensional parameters of periodic structures with lateral resolution of a few nanometer. It is robust enough for in-line process control and precise and accurate enough for metrology measurements. Furthermore, scatterometry is a non-destructive technique capable of measuring buried structures, for example a grating covered by a thick oxide layer. As scatterometry is a non-imaging technique, mathematical modeling is needed to retrieve structural parameters that describe a surface. In this review, the three main steps of scatterometry are discussed: the data acquisition, the simulation of diffraction efficiencies and the comparison of data and simulations. First, the intensity of the diffracted light is measured with a scatterometer as a function of incoming angle, diffraction angle and/or wavelength. We discuss the evolution of the scatterometers from the earliest angular scatterometers to the new imaging scatterometers. The basic principle of measuring diffraction efficiencies in scatterometry has remained the same since the beginning, but the instrumental improvements have made scatterometry a state-of-the-art solution for fast and accurate measurements of nano-textured surfaces. The improvements include extending the wavelength range from the visible to the extreme ultra-violet range, development of Fourier optics to measure all diffraction orders simultaneously, and an imaging scatterometer to measure area of interests smaller than the spot size. Secondly, computer simulations of the diffraction efficiencies are discussed with emphasis on the rigorous coupled-wave analysis (RCWA) method. RCWA has, since the mid-1990s, been the preferred method for grating simulations due to the speed of the algorithms. In the beginning the RCWA method suffered from a very slow convergence rate, and we discuss the historical improvements to overcome this challenge, e.g. by the introduction of Li’s factorization rules and the introduction of the normal vector method. The third step is the comparison, where the simulated diffraction efficiencies are compared to the experimental data using an inverse modeling approach. We discuss both a direct optimization scheme using a differential evolution algorithm and a library search strategy where diffraction efficiences of expected structures are collected in a database. For metrology measurements two methods are described for estimating the uncertainty of the fitting parameters. The first method is based on estimating the confidence limits using constant chi square boundaries, which can easily be computed when using the library search strategy. The other method is based on calculating the covariances of all the free parameters using a least square optimization. Scatterometry is already utilized in the semiconductor industry for in-line characterization. However, it also has a large potential for other industrial sectors, including sectors making use of injection molding or roll-2-roll fabrication. Using the library search strategy, the comparison can be performed in ms, making in-line characterization possible and we demonstrate that scatterometry can be used for quality control of injection molded nano-textured plastic samples. With the emerging methods of highly parallel manufacturing of nano-textured devices, scatterometry has great potential to deliver a characterization method for in-line quality control and metrology measurements, which is not possible with conventional characterization techniques. However, there are some open challenges for the scatterometry techniques. These include corrections for measuring on non-ideal samples with a large surface roughness or line-edge roughness and the path towards performing traceable scatterometry measurements.

DNA profiling analysis of endometrial and ovarian cell lines reveals misidentification, redundancy and contamination.

PubMed

Korch, Christopher; Spillman, Monique A; Jackson, Twila A; Jacobsen, Britta M; Murphy, Susan K; Lessey, Bruce A; Jordan, V Craig; Bradford, Andrew P

2012-10-01

Cell lines derived from human ovarian and endometrial cancers, and their immortalized non-malignant counterparts, are critical tools to investigate and characterize molecular mechanisms underlying gynecologic tumorigenesis, and facilitate development of novel therapeutics. To determine the extent of misidentification, contamination and redundancy, with evident consequences for the validity of research based upon these models, we undertook a systematic analysis and cataloging of endometrial and ovarian cell lines. Profiling of cell lines by analysis of DNA microsatellite short tandem repeats (STR), p53 nucleotide polymorphisms and microsatellite instability was performed. Fifty-one ovarian cancer lines were profiled with ten found to be redundant and five (A2008, OV2008, C13, SK-OV-4 and SK-OV-6) identified as cervical cancer cells. Ten endometrial cell lines were analyzed, with RL-92, HEC-1A, HEC-1B, HEC-50, KLE, and AN3CA all exhibiting unique, uncontaminated STR profiles. Multiple variants of Ishikawa and ECC-1 endometrial cancer cell lines were genotyped and analyzed by sequencing of mutations in the p53 gene. The profile of ECC-1 cells did not match the EnCa-101 tumor, from which it was reportedly derived, and all ECC-1 isolates were genotyped as Ishikawa cells, MCF-7 breast cancer cells, or a combination thereof. Two normal, immortalized endometrial epithelial cell lines, HES cells and the hTERT-EEC line, were identified as HeLa cervical carcinoma and MCF-7 breast cancer cells, respectively. Results demonstrate significant misidentification, duplication, and loss of integrity of endometrial and ovarian cancer cell lines. Authentication by STR DNA profiling is a simple and economical method to verify and validate studies undertaken with these models. Copyright © 2012 Elsevier Inc. All rights reserved.

The Impact of Standard Semiconductor Fabrication Processes on Polycrystalline Nb Thin Film Surfaces

NASA Technical Reports Server (NTRS)

Brown, Ari David; Barrentine, Emily M.; Moseley, Samuel H.; Noroozian, Omid; Stevenson, Thomas

2011-01-01

Polycrystalline superconducting Nb thin films are extensively used for submillimeter and millimeter transmission line applications and, less commonly, used in microwave kinetic inductance detector (MKID) applications. The microwave and mm-wave loss in these films is impacted, in part, by the presence of surface nitrides and oxides. In this study, glancing incidence x-ray diffraction was used to identify the presence of niobium nitride and niobium monoxide surface layers on Nb thin films which had been exposed to chemicals used in standard photolithographic processing. A method of mitigating the presence of ordered niobium monoxide surface layers is presented. Furthermore, we discuss the possibility of using glancing incidence x-ray diffraction as a non-destructive diagnostic tool for evaluating the quality of Nb thin films used in MKIDs and transmission lines. For a given fabrication process, we have both the x-ray diffraction data of the surface chemistry and a measure of the mm-wave and microwave loss, the latter being made in superconducting resonators.

Phase purity of NiCo2O4, a catalyst candidate for electrolysis of water

NASA Technical Reports Server (NTRS)

Singer, J.; Fielder, W. L.; Garlick, R. G.; Negas, T.

1987-01-01

NiCo2O4 is shown to be difficult to obtain as a pure phase, and may never have been so obtained. High resolution x-ray diffractometry is required for its precise characterization. Film XRD is not likely to show the asymmetry in the spinel diffraction lines, caused by poorly crystallized NiO, as seen in diffractometer traces. The Co3O4 which is expected to accompany NiO as an impurity in NiCo2O4 syntheses has the same diffraction pattern as the binary oxide. Firings of the co-precipitated hydroxides at 300, 350, and 400 C, including one in pure O2, failed to produce single phase cobaltate. Scanning electron microscopy showed all the sintered products to range over several orders of magnitude in agglomerate/particle size. Surface areas by BET were all in the range 40 to 110 m sq/g, equivalent to particles of 200 to 100 Angstrom diameter. The spinel diffraction line breadths were compatible with those approximate dimensions.

The Impact of Standard Semiconductor Fabrication Processes on Polycrystalline Nb Thin Film Surfaces

NASA Technical Reports Server (NTRS)

Brown, Ari David; Barrentine, Emily M.; Moseley, Samuel H.; Noroozian, Omid; Stevenson, Thomas

2016-01-01

Polycrystalline Nb thin films are extensively used for microwave kinetic inductance detectors (MKIDs) and superconducting transmission line applications. The microwave and mm-wave loss in these films is impacted, in part, by the presence of surface nitrides and oxides. In this study, glancing incidence x-ray diffraction was used to identify the presence of niobium nitride and niobium monoxide surface layers on Nb thin films which had been exposed to chemicals used in standard photolithographic processing. A method of mitigating the presence of ordered niobium monoxide surface layers is presented. Furthermore, we discuss the possibility of using glancing incidence x-ray diffraction as a non-destructive diagnostic tool for evaluating the quality of Nb thin films used in MKIDs and transmission lines. For a given fabrication process, we have both the X-ray diffraction data of the surface chemistry and a measure of the mm-wave and microwave loss, the latter being made in superconducting resonators.

Improving the performance of methylene blue sensitized photopolymer by doping with nickel ion

NASA Astrophysics Data System (ADS)

Aswathy, G.; Rajesh, C. S.; Sreekumar, K.; Joseph, R.; Kartha, C. Sudha

2016-05-01

Holographic performance of an economically cheap metal ion doped photopolymer material is presented. We investigated the effect of incorporation of nickel ion into the methylene blue sensitized poly (vinyl alcohol)/acrylamide (MBPVA/AA) photopolymer system. The composition and preliminary characterization of the developed photopolymer material is reported. The presence of nickel ion improves the diffraction efficiency, stability of the material and it operates in a wide range of spatial frequencies (550-2000 lines/mm) at exposure energy of 100 mJ/cm2. When nickel ion concentration was 0.01 mM, maximum diffraction efficiency of 84% at exposure energy of 100 mJ/cm2 with spatial frequency 1335 lines/mm could be achieved for gratings recorded using wavelength of 632.8 nm. The material showed panchromaticity with more than 70% diffraction efficiency in both blue and green regions. Effects of humidity and temperature on the stored gratings were studied by keeping films in different environmental conditions. Suitability of recording large area holograms was also explored.

Residual stresses and plastic deformation in GTA-welded steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brand, P.C.; Keijser, T.H. de; Ouden, G. den

1993-03-01

Residual stresses and plastic deformation in single pass GTA welded low-carbon steel were studied by means of x-ray diffraction in combination with optical microscopy and hardness measurements. The residual stresses and the amount of plastic deformation (microstrain) were obtained from x-ray diffraction line positions and line broading. Since the plates were polished before welding, it was possible to observe in the optical microscope two types of Lueders bands. During heating curved Lueders bands and during cooling straight Lueders bands perpendicular to the weld are formed. The curved Lueders bands extend over a larger distance from the weld than the straightmore » Lueders bands. The amount of plastic deformation as obtained from the x-ray diffraction analysis is in agreement with these observations. An explanation is offered for the stresses measured in combination with plastic deformations observed. It is concluded that in the present experiments plastic deformation is the main cause of the residual stresses.« less

Deuterium and the Local Interstellar Medium: Properties for the Procyon and Capella Lines of Sight

NASA Technical Reports Server (NTRS)

Linsky, Jeffrey L.; Diplas, Athanassios; Wood, Brian E.; Brown, Alexander; Ayres, Thomas R.; Savage, Blair D.

1995-01-01

We present Goddard High-Resolution Spectrograph observations of the interstellar H I and D I Ly-alpha lines and the Mg II and Fe II resonance lines formed along the lines of sight toward the nearby stars Procyon (3.5 pc, l = 214 deg, b = 13 deg) and Capella (12.5 pc, l = 163 deg, b = 5 deg). New observations of Capella were obtained at orbital phase 0.80, when the radial velocities of the intrinsic Ly-alpha emission lines of each star were nearly reversed from those of the previous observations at phase 0.26. Since the intrinsic Ly-alpha line of the Capella system (the 'continuum' against which the interstellar absorption is measured) has different shapes at phases 0.26 and 0.80, we can derive both the intrinsic stellar profiles and the interstellar absorption lines more precisely by jointly analyzing the two data sets. For the analysis of the Procyon line of sight, we first assumed that the intrinsic Ly-alpha line profile is a broadened solar profile, but this assumption does not lead to a good fit to the observed D I line profile for any value of D/H. We then assumed that (D/H)(sub LISM) = 1.6 x 10(exp -5), the same value as for the Capella line of sight, and we modified the broadened solar profile to achieve agreement between the simulated and observed line profiles. The resulting asymmetric intrinsic stellar line profile is consistent with the shapes of the scaled Mg II line profiles. We believe therefore that the Procyon data are consistent with (D/H)(sub LISM) = 1.6 x 10(exp -5), but the uncertainty in the intrinsic Ly-alpha emission-line profile does not permit us to conclude that the D/H ratio is constant in the local interstellar medium (LISM). The temperature and turbulence in the Procyon line of sight are T = 6900 +/- 80 (+/- 300 systematic error) K and zeta = 1.21 +/- 0.27 km/s. These properties are similar to those of Capella, except that the gas toward Procyon is divided into two velocity components separated by 2.6 km/s and the Procyon line of sight has a mean neutral hydrogen density that is a factor of 2.4 larger than that of the Capella line of sight. This suggests that the first 5.3 pc along the Capella line of sight lies within the local cloud and the remaining 7.2 pc lies in the hot gas surrounding the local cloud. We propose that n(H I) = 0.1065 +/- 0.0028 cm(exp -2) be adopted for the neutral hydrogen density within the local cloud and that zeta = 1.21 +/- 0.27 km/s be adopted for the nonthermal motions. The existence of different second velocity components toward the nearby stars Procyon and Sirius provides the first glimpse of a turbulent cloudlet boundary layer between the local cloud and the surrounding hot interstellar gas.

Spectra of High-Ionization Seyfert 1 Galaxies: Implications for the Narrow-Line Region

NASA Technical Reports Server (NTRS)

Moore, David; Cohen, Ross D.; Marcy, Geoffrey W.

1996-01-01

We present line profiles and profile parameters for the Narrow-Line Regions (NLRs) of six Seyfert 1 galaxies with high-ionization lines: MCG 8-11-11, Mrk 79, Mrk 704, Mrk 841, NGC 4151, and NGC 5548. The sample was chosen primarily with the goal of obtaining high-quality [Fe VII] lambda6087 and, when possible, [Fe X] lambda6374 profiles to determine if these lines are more likely formed in a physically distinct 'coronal line region' or are formed throughout the NLR along with lines of lower critical density (n(sub cr)) and/or Ionization Potential (IP). We discuss correlations of velocity shift and width with n(sub cr) and IP. In some objects, lines of high IP and/or n(sub cr) are systematically broader than those of low IP/n(sub cr). Of particular interest, however, are objects that show no correlations of line width with either IP or n(sub cr). In these objects, lines of high and low IP/n(sub cr), are remarkably similar, which is difficult to reconcile with the classical picture of the NLR, in which lines of high and low IP/n(sub cr) are formed in physically distinct regions. We argue for similar spatial extents for the flux in lines with similar profiles. Here, as well as in a modeling-oriented companion paper, we develop further an idea suggested by Moore & Cohen that objects that do and do not show line width correlations with IP/n(sub cr) can both be explained in terms of a single NLR model with only a small difference in the cloud column density distinguishing the two types of object. Overall, our objects do not show correlations between the Full Width at Half-Maximum (FWHM) and IP and/or n(sub cr). The width must be defined by a parameter that is sensitive to extended profile wings in order for the correlations to result. We present models in which FWHM correlations with IP and/or n(sub cr) result only after simulating the lower spectral resolution used in previous observational studies. The models that simulate the higher spectral resolution of our observational study produce line width correlations only if the width is defined by a parameter that is more sensitive to extended profile wings than is the FWHM. Our sample of six objects is in effect augmented by incorporating the larger sample (16 objects) of Veilleux into some of our discussion. This paper focuses on new interpretations of NLR emission-line spectra and line profiles that stem directly from the observations. Paper 2 focuses on modeling and complements this paper by illustrating explicitly the effects that spatial variations in electron density, ionization parameter, and column density have on model profiles. By comparing model profiles with the observed profiles presented here, as well as with those presented by Veilleux, Paper 2 yields insight into how the electron density, ionization parameter, and column density likely vary throughout the NLR.

Linear Fresnel Spectrometer Chip with Gradient Line Grating

NASA Technical Reports Server (NTRS)

Choi, Sang Hyouk (Inventor); Park, Yeonjoon (Inventor)

2015-01-01

A spectrometer that includes a grating that disperses light via Fresnel diffraction according to wavelength onto a sensing area that coincides with an optical axis plane of the grating. The sensing area detects the dispersed light and measures the light intensity associated with each wavelength of the light. Because the spectrometer utilizes Fresnel diffraction, it can be miniaturized and packaged as an integrated circuit.

Real-time x-ray diffraction measurements of shocked polycrystalline tin and aluminum.

PubMed

Morgan, Dane V; Macy, Don; Stevens, Gerald

2008-11-01

A new, fast, single-pulse x-ray diffraction (XRD) diagnostic for determining phase transitions in shocked polycrystalline materials has been developed. The diagnostic consists of a 37-stage Marx bank high-voltage pulse generator coupled to a needle-and-washer electron beam diode via coaxial cable, producing line and bremsstrahlung x-ray emission in a 35 ns pulse. The characteristic K(alpha) lines from the selected anodes of silver and molybdenum are used to produce the diffraction patterns, with thin foil filters employed to remove the characteristic K(beta) line emission. The x-ray beam passes through a pinhole collimator and is incident on the sample with an approximately 3 x 6 mm(2) spot and 1 degrees full width half maximum angular divergence in a Bragg-reflecting geometry. For the experiments described in this report, the angle between the incident beam and the sample surface was 8.5 degrees . A Debye-Scherrer diffraction image was produced on a phosphor located 76 mm from the polycrystalline sample surface. The phosphor image was coupled to a charge-coupled device camera through a coherent fiber-optic bundle. Dynamic single-pulse XRD experiments were conducted with thin foil samples of tin, shock loaded with a 1 mm vitreous carbon back window. Detasheet high explosive with a 2-mm-thick aluminum buffer was used to shock the sample. Analysis of the dynamic shock-loaded tin XRD images revealed a phase transformation of the tin beta phase into an amorphous or liquid state. Identical experiments with shock-loaded aluminum indicated compression of the face-centered-cubic aluminum lattice with no phase transformation.

Determination of the vinyl fluoride line intensities by TDL spectroscopy: the object oriented approach of Visual Line Shape Fitting Program to line profile analysis

NASA Astrophysics Data System (ADS)

Tasinato, Nicola; Pietropolli Charmet, Andrea; Stoppa, Paolo; Giorgianni, Santi

2010-03-01

In this work the self-broadening coefficients and the integrated line intensities for a number of ro-vibrational transitions of vinyl fluoride have been determined for the first time by means of TDL spectroscopy. The spectra recorded in the atmospheric window around 8.7 µm appear very crowded with a density of about 90 lines per cm-1. In order to fit these spectral features a new fitting software has been implemented. The program, which is designed for laser spectroscopy, can fit many lines simultaneously on the basis of different theoretical profiles (Doppler, Lorentz, Voigt, Galatry and Nelkin-Ghatak). Details of the object oriented implementation of the application are given. The reliability of the program is demonstrated by determining the line parameters of some ro-vibrational lines of sulphur dioxide in the ν1 band region around 9 µm. Then the software is used for the line profile analysis of vinyl fluoride. The experimental line shapes show deviations from the Voigt profile, which can be well modelled by using a Dicke narrowed line shape function. This leads to the determination of the self-narrowing coefficient within the framework of the strong collision model.

Multiobjective optimizations of a novel cryocooled dc gun based ultrafast electron diffraction beam line

NASA Astrophysics Data System (ADS)

Gulliford, Colwyn; Bartnik, Adam; Bazarov, Ivan

2016-09-01

We present the results of multiobjective genetic algorithm optimizations of a single-shot ultrafast electron diffraction beam line utilizing a 225 kV dc gun with a novel cryocooled photocathode system and buncher cavity. Optimizations of the transverse projected emittance as a function of bunch charge are presented and discussed in terms of the scaling laws derived in the charge saturation limit. Additionally, optimization of the transverse coherence length as a function of final rms bunch length at the sample location have been performed for three different sample radii: 50, 100, and 200 μ m , for two final bunch charges: 1 05 electrons (16 fC) and 1 06 electrons (160 fC). Example optimal solutions are analyzed, and the effects of disordered induced heating estimated. In particular, a relative coherence length of Lc ,x/σx=0.27 nm /μ m was obtained for a final bunch charge of 1 05 electrons and final bunch length of σt≈100 fs . For a final charge of 1 06 electrons the cryogun produces Lc ,x/σx≈0.1 nm /μ m for σt≈100 - 200 fs and σx≥50 μ m . These results demonstrate the viability of using genetic algorithms in the design and operation of ultrafast electron diffraction beam lines.

XRayView: a teaching aid for X-ray crystallography.

PubMed

Phillips, G N

1995-10-01

A software package, XRayView, has been developed that uses interactive computer graphics to introduce basic concepts of x-ray diffraction by crystals, including the reciprocal lattice, the Ewald sphere construction, Laue cones, the wavelength dependence of the reciprocal lattice, primitive and centered lattices and systematic extinctions, rotation photography. Laue photography, space group determination and Laue group symmetry, and the alignment of crystals by examination of reciprocal space. XRayView is designed with "user-friendliness" in mind, using pull-down menus to control the program. Many of the experiences of using real x-ray diffraction equipment to examine crystalline diffraction can be simulated. Exercises are available on-line to guide the users through many typical x-ray diffraction experiments.

Absorption profiles of the potassium 4s-4p and 4p-5s lines perturbed by helium

NASA Astrophysics Data System (ADS)

Allard, N. F.

2011-12-01

An accurate determination of the complete profile including the extreme far wing is required to model the contribution of strong alkali resonance lines to brown dwarf spectra. A unified theory of collisional line profiles has been applied for the evaluation of the absorption coefficients of potassium perturbed by helium. Results are reported here from the optical range to the near-infrared.

Ultraviolet line diagnostics of accretion disk winds in cataclysmic variables

NASA Technical Reports Server (NTRS)

Vitello, Peter; Shlosman, Isaac

1993-01-01

The IUE data base is used to analyze the UV line shapes of the cataclysmic variables RW Sex, RW Tri, and V Sge. Observed lines are compared to synthetic line profiles computed using a model of rotating biconical winds from accretion disks. The wind model calculates the wind ionization structure self-consistently including photoionization from the disk and boundary layer and treats 3D line radiation transfer in the Sobolev approximation. It is found that winds from accretion disks provide a good fit for reasonable parameters to the observed UV lines which include the P Cygni profiles for low-inclination systems and pure emission at large inclination. Disk winds are preferable to spherical winds which originate on the white dwarf because they: (1) require a much lower ratio of mass-loss rate to accretion rate and are therefore more plausible energetically; (2) provide a natural source for a biconical distribution of mass outflow which produces strong scattering far above the disk leading to P Cygni profiles for low-inclination systems and pure line emission profiles at high inclination with the absence of eclipses in UV lines; and (3) produce rotation-broadened pure emission lines at high inclination.

UV line diagnostics of accretion disk winds in cataclysmic variables

NASA Technical Reports Server (NTRS)

Vitello, Peter; Shlosman, Isaac

1992-01-01

The IUE data base is used to analyze the UV line shapes of cataclysmic variables RW Sex, RW Tri, and V Sge. Observed lines are compared to synthetic line profiles computed using a model of rotating bi-conical winds from accretion disks. The wind model calculates the wind ionization structure self-consistently including photoionization from the disk and boundary layer and treats 3-D line radiation transfer in the Sobolev approximation. It is found that winds from accretion disks provide a good fit for reasonable parameters to the observed UV lines which include the P Cygni profiles for low inclination systems and pure emission at large inclination. Disk winds are preferable to spherical winds which originate on the white dwarf because they (1) require a much lower ratio of mass loss rate to accretion rate and are therefore more plausible energetically, (2) provide a natural source for a bi-conical distribution of mass outflow which produces strong scattering far above the disk leading to P Cygni profiles for low inclination systems, and pure line emission profiles at high inclination with the absence of eclipses in UV lines, and (3) produce rotation broadened pure emission lines at high inclination.

Crevasse detection with GPR across the Ross Ice Shelf, Antarctica

NASA Astrophysics Data System (ADS)

Delaney, A.; Arcone, S.

2005-12-01

We have used 400-MHz ground penetrating radar (GPR) to detect crevasses within a shear zone on the Ross Ice Shelf, Antarctica, to support traverse operations. The transducer was attached to a 6.5-m boom and pushed ahead of an enclosed tracked vehicle. Profile speeds of 4.8-11.3 km / hr allowed real-time crevasse image display and a quick, safe stop when required. Thirty-two crevasses were located with radar along the 4.8 km crossing. Generally, crevasse radar images were characterized by dipping reflections above the voids, high-amplitude reflections originating from ice layers at the base of the snow-bridges, and slanting, diffracting reflections from near-vertical crevasse walls. New cracks and narrow crevasses (<50 cm width) show no distinct snow bridge structure, few diffractions, and a distinct band where pulse reflections are absent. Wide (0.5-5.0 m), vertical wall crevasses show distinct dipping snow bridge layering and intense diffractions from ice layers near the base of the snow bridge. Pulse reflections are absent from voids beneath the snow bridges. Old, wide (3.0-8.0 m) and complexly shaped crevasses show well-developed, broad, dipping snow-bridge layers and a high-amplitude, complex, diffraction pattern. The crevasse mitigation process, which included hot-water drilling, destroying the bridges with dynamite, and back-filling with bulldozed snow, afforded an opportunity to ground-truth GPR interpretations by comparing void size and snow-bridge geometry with the radar images. While second and third season radar profiles collected along the identical flagged route confirmed stability of the filled crevasses, those profiles also identified several new cracks opened by ice extension. Our experiments demonstrate capability of high-frequency GPR in a cold-snow environment for both defining snow layers and locating voids.

Line profile studies of hydrodynamical models of cometary compact H II regions

NASA Astrophysics Data System (ADS)

Zhu, Feng-Yao; Zhu, Qing-Feng

2015-06-01

We simulate the evolution of cometary H II regions based on several champagne flow models and bow shock models, and calculate the profiles of the [Ne II] fine-structure line at 12.81 μm, the H30α recombination line and the [Ne III] fine-structure line at 15.55 μm for these models at different inclinations of 0°, 30° and 60°. We find that the profiles in the bow shock models are generally different from those in the champagne flow models, but the profiles in the bow shock models with lower stellar velocity (≤ 5 km s-1) are similar to those in the champagne flow models. In champagne flow models, both the velocity of peak flux and the flux weighted central velocities of all three lines point outward from molecular clouds. In bow shock models, the directions of these velocities depend on the speed of stars. The central velocities of these lines are consistent with the stellar motion in the high stellar speed cases, but they are opposite directions from the stellar motion in the low speed cases. We notice that the line profiles from the slit along the symmetrical axis of the projected 2D image of these models are useful for distinguishing bow shock models from champagne flow models. It is also confirmed by the calculation that the flux weighted central velocity and the line luminosity of the [Ne III] line can be estimated from the [Ne II] line and the H30α line.

Interactive spectral analyzer and comparator (ISAAC)

NASA Astrophysics Data System (ADS)

Latković, O.; Cséki, A.; Vince, I.

2003-10-01

We are developing an application for graphical comparison of observed and synthetic spectra (ISAAC). Synthetic spectrum calculation is performed by SPECTRUM, Stellar Spectral Synthesis Program by Richard O. Gray that we use with his kind permission. This program computes line profiles under LTE conditions in the given wavelength interval using a stellar (solar) atmosphere model, a spectral line data list (wavelength, energy levels, oscillator strengths, and damping constants), a file containing data for atoms and molecules, as well as a data file for hydrogen line profiles calculation. ISAAC offers a simple interface for viewing and changing any atomic parameter SPECTRUM uses for line profile calculation, enabling quick comparison of the new synthetic line profile with the observed one. In this way parameters like relative abundances, oscillator strengths and van der Waals damping constants can be improved, achieving a better agreement with the observed spectrum.

Disorder-induced losses in photonic crystal waveguides with line defects.

PubMed

Gerace, Dario; Andreani, Lucio Claudio

2004-08-15

A numerical analysis of extrinsic diffraction losses in two-dimensional photonic crystal slabs with line defects is reported. To model disorder, a Gaussian distribution of hole radii in the triangular lattice of airholes is assumed. The extrinsic losses below the light line increase quadratically with the disorder parameter, decrease slightly with increasing core thickness, and depend weakly on the hole radius. For typical values of the disorder parameter the calculated loss values of guided modes below the light line compare favorably with available experimental results.

Diffraction-Induced Bidimensional Talbot Self-Imaging with Full Independent Period Control

NASA Astrophysics Data System (ADS)

Guillet de Chatellus, Hugues; Romero Cortés, Luis; Deville, Antonin; Seghilani, Mohamed; Azaña, José

2017-03-01

We predict, formulate, and observe experimentally a generalized version of the Talbot effect that allows one to create diffraction-induced self-images of a periodic two-dimensional (2D) waveform with arbitrary control of the image spatial periods. Through the proposed scheme, the periods of the output self-image are multiples of the input ones by any desired integer or fractional factor, and they can be controlled independently across each of the two wave dimensions. The concept involves conditioning the phase profile of the input periodic wave before free-space diffraction. The wave energy is fundamentally preserved through the self-imaging process, enabling, for instance, the possibility of the passive amplification of the periodic patterns in the wave by a purely diffractive effect, without the use of any active gain.

Diffraction-Induced Bidimensional Talbot Self-Imaging with Full Independent Period Control.

PubMed

Guillet de Chatellus, Hugues; Romero Cortés, Luis; Deville, Antonin; Seghilani, Mohamed; Azaña, José

2017-03-31

We predict, formulate, and observe experimentally a generalized version of the Talbot effect that allows one to create diffraction-induced self-images of a periodic two-dimensional (2D) waveform with arbitrary control of the image spatial periods. Through the proposed scheme, the periods of the output self-image are multiples of the input ones by any desired integer or fractional factor, and they can be controlled independently across each of the two wave dimensions. The concept involves conditioning the phase profile of the input periodic wave before free-space diffraction. The wave energy is fundamentally preserved through the self-imaging process, enabling, for instance, the possibility of the passive amplification of the periodic patterns in the wave by a purely diffractive effect, without the use of any active gain.

He I lines in B stars - Comparison of non-local thermodynamic equilibrium models with observations

NASA Technical Reports Server (NTRS)

Heasley, J. N.; Timothy, J. G.; Wolff, S. C.

1982-01-01

Profiles of He gamma-gamma 4026, 4387, 4471, 4713, 5876, and 6678 have been obtained in 17 stars of spectral type B0-B5. Parameters of the nonlocal thermodynamic equilibrium models appropriate to each star are determined from the Stromgren index and fits to H-alpha line profiles. These parameters yield generally good fits to the observed He I line profiles, with the best fits being found for the blue He I lines where departures from local thermodynamic equilibrium are relatively small. For the two red lines it is found that, in the early B stars and in stars with log g less than 3.5, both lines are systematically stronger than predicted by the nonlocal thermodynamic equilibrium models.

An evaluation of the clinical potential of tissue diffraction studies

NASA Astrophysics Data System (ADS)

Speller, R.; Abuchi, S.; Zheng, Y.; Vassiljev, N.; Konstantinidis, A.; Griffiths, J.

2015-09-01

Medical imaging is a long established part of patient management in the treatment of disease. However, in most cases it only provides anatomical detail and does not provide any form of tissue characterisation. This is particularly true for X-ray imaging. Recent studies on tissue diffraction have shown that true molecular signatures can be derived for different tissue types. Breast cancer samples and liver tissue have been studied. It has been shown that diffraction profiles can be traced away from the primary tumour in excised breast tissue samples and that potentially 3mm fat nodules in liver tissue can be identified in patients at acceptable doses.

Investigation of the dependence of deformation mechanisms on solute content in polycrystalline Mg–Al magnesium alloys by neutron diffraction and acoustic emission

DOE PAGES

Mathis, Kristian; Capek, J.; Clausen, Bjorn; ...

2015-04-20

Influence of aluminium content on the deformation mechanisms in Mg–Al binary alloys has been studied using in-situ neutron diffraction and acoustic emission technique. Here, it is shown that the addition of the solute increases the critical resolved shear stress for twinning. Further, the role of aluminium on the solid solution hardening of the basal plane and softening of non-basal planes are discussed using results of the convolutional multiple peak profile analysis of diffraction patterns. In conclusion, the results indicate that the density of both prismatic and pyramidal dislocations increases with increasing alloying content.

Dark localized structures in a cavity filled with a left-handed material

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tlidi, Mustapha; Kockaert, Pascal; Gelens, Lendert

2011-07-15

We consider a nonlinear passive optical cavity filled with left-handed and right-handed materials and driven by a coherent injected beam. We assume that both left-handed and right-handed materials possess a Kerr focusing type of nonlinearity. We show that close to the zero-diffraction regime, high-order diffraction allows us to stabilize dark localized structures in this device. These structures consist of dips in the transverse profile of the intracavity field and do not exist without high-order diffraction. We analyze the snaking bifurcation diagram associated with these structures. Finally, a realistic estimation of the model parameters is provided.

Time-resolved coherent X-ray diffraction imaging of surface acoustic waves

PubMed Central

Nicolas, Jan-David; Reusch, Tobias; Osterhoff, Markus; Sprung, Michael; Schülein, Florian J. R.; Krenner, Hubert J.; Wixforth, Achim; Salditt, Tim

2014-01-01

Time-resolved coherent X-ray diffraction experiments of standing surface acoustic waves, illuminated under grazing incidence by a nanofocused synchrotron beam, are reported. The data have been recorded in stroboscopic mode at controlled and varied phase between the acoustic frequency generator and the synchrotron bunch train. At each time delay (phase angle), the coherent far-field diffraction pattern in the small-angle regime is inverted by an iterative algorithm to yield the local instantaneous surface height profile along the optical axis. The results show that periodic nanoscale dynamics can be imaged at high temporal resolution in the range of 50 ps (pulse length). PMID:25294979

Time-resolved coherent X-ray diffraction imaging of surface acoustic waves.

PubMed

Nicolas, Jan-David; Reusch, Tobias; Osterhoff, Markus; Sprung, Michael; Schülein, Florian J R; Krenner, Hubert J; Wixforth, Achim; Salditt, Tim

2014-10-01

Time-resolved coherent X-ray diffraction experiments of standing surface acoustic waves, illuminated under grazing incidence by a nanofocused synchrotron beam, are reported. The data have been recorded in stroboscopic mode at controlled and varied phase between the acoustic frequency generator and the synchrotron bunch train. At each time delay (phase angle), the coherent far-field diffraction pattern in the small-angle regime is inverted by an iterative algorithm to yield the local instantaneous surface height profile along the optical axis. The results show that periodic nanoscale dynamics can be imaged at high temporal resolution in the range of 50 ps (pulse length).

Diffraction-based BioCD biosensor for point-of-care diagnostics

NASA Astrophysics Data System (ADS)

Choi, H.; Chang, C.; Savran, C.; Nolte, D.

2018-02-01

The BioCD platform technology uses spinning-disk interferometry to detect molecular binding to target molecular probes in biological samples. Interferometric configurations have included differential phase contrast and in-line quadrature detection. For the detection of extremely low analyte concentrations, nano- or microparticles can enhance the signal through background-free diffraction detection. Diffraction signal measurements on BioCD biosensors are achieved by forming gratings on a disc surface. The grating pattern was printed with biotinylated bovine serum albumin (BSA) and streptavidin coated beads were deployed. The diameter of the beads was 1 micron and strong protein bonding occurs between BSA and streptavidin-coated beads at the printed location. The wavelength for the protein binding detection was 635 nm. The periodic pattern on the disc amplified scattered light into the first-order diffraction position. The diffracted signal contains Mie scattering and a randomly-distributed-bead noise contributions. Variation of the grating pattern periodicity modulates the diffraction efficiency. To test multiple spatial frequencies within a single scan, we designed a fan-shaped grating to perform frequency filter multiplexing on a diffraction-based BioCD.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayashida, Misa; Malac, Marek; Egerton, Ray F.

Electron tomography is a method whereby a three-dimensional reconstruction of a nanoscale object is obtained from a series of projected images measured in a transmission electron microscope. We developed an electron-diffraction method to measure the tilt and azimuth angles, with Kikuchi lines used to align a series of diffraction patterns obtained with each image of the tilt series. Since it is based on electron diffraction, the method is not affected by sample drift and is not sensitive to sample thickness, whereas tilt angle measurement and alignment using fiducial-marker methods are affected by both sample drift and thickness. The accuracy ofmore » the diffraction method benefits reconstructions with a large number of voxels, where both high spatial resolution and a large field of view are desired. The diffraction method allows both the tilt and azimuth angle to be measured, while fiducial marker methods typically treat the tilt and azimuth angle as an unknown parameter. The diffraction method can be also used to estimate the accuracy of the fiducial marker method, and the sample-stage accuracy. A nano-dot fiducial marker measurement differs from a diffraction measurement by no more than ±1°.« less

Four-wave parametric oscillation in sodium vapor by electromagnetically induced diffraction.

PubMed

Harada, Ken-ichi; Ogata, Minoru; Mitsunaga, Masaharu

2007-05-01

We have observed a novel type of parametric oscillation in sodium atomic vapor where four off-axis signal waves simultaneously build up under resonant and counterpropagating pump beams with elliptical beam profiles. The four waves, two of them Stokes shifted and the other two anti-Stokes shifted, have similar output powers of up to 10 mW with a conversion efficiency of 30% and are parametrically coupled by electromagnetically induced diffraction.

Digital model for X-ray diffraction with application to composition and strain determination in strained InAs/GaSb superlattices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meng, Yifei; Kim, Honggyu; Zuo, Jian-Min

2014-07-07

We propose a digital model for high quality superlattices by including fluctuations in the superlattice periods. The composition and strain profiles are assumed to be coherent and persist throughout the superlattice. Using this model, we have significantly improved the fit with experimental X-ray diffraction data recorded from the nominal InAs/GaSb superlattice. The lattice spacing of individual layers inside the superlattice and the extent of interfacial intermixing are refined by including both (002) and (004) and their satellite peaks in the fitting. For the InAs/GaSb strained layer superlattice, results show: (i) the GaSb-on-InAs interface is chemically sharper than the InAs-on-GaSb interface,more » (ii) the GaSb layers experience compressive strain with In incorporation, (iii) there are interfacial strain associated with InSb-like bonds in GaSb and GaAs-like bonds in InAs, (iv) Sb substitutes a significant amount of In inside InAs layer near the InAs-on-GaSb interface. For support, we show that the composition profiles determined by X-ray diffraction are in good agreement with those obtained from atom probe tomography measurement. Comparison with the kinetic growth model shows a good agreement in terms of the composition profiles of anions, while the kinetic model underestimates the intermixing of cations.« less

Kinetic-Energy Distribution of D(2p) Atoms from Analysis of the D Lyman-Alpha Line Profile

NASA Technical Reports Server (NTRS)

Ciocca, M.; Ajello, Joseph M.; Liu, Xianming; Maki, Justin

1997-01-01

The kinetic-energy distribution of D(2p) atoms resulting from electron-impact dissociation of D2 has been measured. A high-resolution vacuum ultraviolet spectrometer was employed for the first measurement of the D Lyman-alpha (D L(alpha)) emission line profiles at 20- and 100-eV excitation energies. Analysis of the deconvoluted line profile of D L(alpha) at 100 eV reveals the existence of a narrow line central peak of 29+/-2 mA full width at half maximum and a broad pedestal wing structure about 190 mA wide. The wings of the line can be used to determine the fast atom distribution. The wings of D L(alpha) arise from dissociative excitation of a series of doubly excited states that cross the Franck-Condon region between 23 and 40 eV. The fast atom distribution at 100-eV electron impact energy spans the energy range from 1 to 10 eV with a peak value near 6 eV. Slow D(2p) atoms characterized by a distribution function with peak energy near 100 meV produce the central peak profile, which is nearly independent of the impact energy. The deconvoluted line profiles of the central peak at 20 eV for dissociative excitation of D2 and H2 are fitted with an analytical function for use in calibration of space flight instrumentation equipped with a D/H absorption cell. The kinetic-energy and line profile results are compared to similar measurements for H2. The absolute cross sections for the line center (slow atoms) and wings (fast atoms) and total emission line profile were measured from threshold to 400 eV. Analytical model coefficients are given for the energy dependence of the measured slow atom cross section.

A large area high resolution imaging detector for fast atom diffraction

NASA Astrophysics Data System (ADS)

Lupone, Sylvain; Soulisse, Pierre; Roncin, Philippe

2018-07-01

We describe a high resolution imaging detector based on a single 80 mm micro-channel-plate (MCP) and a phosphor screen mounted on a UHV flange of only 100 mm inner diameter. It relies on standard components and we describe its performance with one or two MCPs. A resolution of 80 μm rms is observed on the beam profile. At low count rate, individual impact can be pinpointed with few μm accuracy but the resolution is probably limited by the MCP channel diameter. The detector has been used to record the diffraction of fast atoms at grazing incidence on crystal surfaces (GIFAD), a technique probing the electronic density of the topmost layer only. The detector was also used to record the scattering profile during azimuthal scan of the crystal to produce triangulation curves revealing the surface crystallographic directions of molecular layers. It should also be compatible with reflection high energy electron (RHEED) experiment when fragile surfaces require a low exposure to the electron beam. The discussions on the mode of operation specific to diffraction experiments apply also to commercial detectors.

Diffraction contrast near heterostructure boundaries--its nature and its application.

PubMed

Bangert, U; Harvey, A J

1993-03-01

Two phenomena of diffraction contrast arising at or near III-V compound heterostructure boundaries are described and quantitatively analyzed. In the first observation alpha/delta-fringe contrast at boundaries inclined to the electron beam is discussed. Theoretical fringe profiles are generated according to the theory by Gevers et al. in 1964, which are then compared with experimental profiles. Applications to the characterization of AlGaAs/GaAs and InGaAsP/InP interfaces regarding composition, abruptness, and lattice tilt are presented. In the second study a new and very sensitive characterization technique for the direct determination of the strain in strained-layer structures is described. The method uses electron microscope images of 90 degrees-wedges, which exhibit a shift in the thickness contours due to strain relaxation at the edge, and compares these to images which are obtained theoretically by implementing finite element strain calculations in wedges in the dynamical theory of diffraction contrast. The considerable potential of this method is demonstrated on the strain analysis of strained GaInAs/GaAs structures.

Comparative study on hydrostatic strain, stress and dislocation density of Al{sub 0.3}Ga{sub 0.7}N/GaN heterostructure before and after a-Si{sub 3}N{sub 4} passivation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dinara, Syed Mukulika, E-mail: smdinara.iit@gmail.com; Jana, Sanjay Kr.; Mukhopadhyay, Partha

2015-08-28

The hydrostatic strain, stress and dislocation densities were comparatively analyzed before and after passivation of amorphous silicon nitride (a-Si{sub 3}N{sub 4}) layer on Al{sub 0.3}Ga{sub 0.7}N/GaN heterostructure by nondestructive high resolution x-ray diffraction (HRXRD) technique. The crystalline quality, in-plane and out-of plane strain were evaluated from triple-axis (TA) (ω-2θ) diffraction profile across the (002) reflection plane and double-axis (DA) (ω-2θ) glancing incidence (GI) diffraction profile across (105) reflection plane. The hydrostatic strain and stress of Al{sub 0.3}Ga{sub 0.7}N barrier layer were increased significantly after passivation and both are tensile in nature. The dislocation density of GaN was also analyzed andmore » no significant change was observed after passivation of the heterostructure. The crystalline quality was not degraded after passivation on the heterostructure confirmed by the full-width-half-maximum (FWHM) analysis.« less

Study of drying process on starch structural properties and their effect on semolina pasta sensory quality.

PubMed

Padalino, Lucia; Caliandro, Rocco; Chita, Giuseppe; Conte, Amalia; Del Nobile, Matteo Alessandro

2016-11-20

The influence of drying temperature on the starch crystallites and its impact on durum wheat pasta sensory properties is addressed in this work. In particular, spaghetti were produced by means of a pilot plant using 5 different drying temperature profiles. The sensory properties, as well as the cooking quality of pasta were assessed. X-ray powder diffraction was used for investigating changes in the crystallinity content of the samples. Starch crystallinity, size and density of the starch crystallites were determined from the analysis of the diffraction profiles. As expected, spaghetti sensory properties improved as the drying temperatures increased. In particular, attributes as resistance to break for uncooked samples and firmness, elasticity, bulkiness and stickiness for cooked samples, all benefit from drying temperature increase. The spaghetti cooking quality was also positively affected by the drying temperature increase. Diffraction analysis suggested that the improvement of sensory properties and cooking quality of pasta were directly related to the increase in density of both physical crosslink of starch granules and chemical crosslink of protein matrix. Copyright © 2016 Elsevier Ltd. All rights reserved.

Induction of cancer cell death by apoptosis and slow release of 5-fluoracil from metal-organic frameworks Cu-BTC.

PubMed

Lucena, Flávia Raquel Santos; de Araújo, Larissa C C; Rodrigues, Maria do D; da Silva, Teresinha G; Pereira, Valéria R A; Militão, Gardênia C G; Fontes, Danilo A F; Rolim-Neto, Pedro J; da Silva, Fausthon F; Nascimento, Silene C

2013-10-01

This study aimed to evaluate the mechanism associated with cytotoxic activity displayed by the drug 5-fluorouracil incorporated in Cu-BTC MOF and its slow delivery from the Cu-BTC MOF. Structural characterization encompasses elemental analysis (CHNS), differential scanning calorimetry (DSC), thermogravimetric analysis (TG/DTG), Fournier transform infrared (FIT-IR) and X-ray diffraction (XRD) was performed to verify the process of association between the drug 5-FU and Cu-BTC MOF. Flow cytometry was done to indicate that apoptosis is the mechanism responsible for the cell death. The release profile of the drug 5-FU from Cu-BTC MOF for 48 hours was obeisant. Also, the anti-inflammatory activity was evaluated by the peritonitis testing and the production of nitric oxide and pro-inflammatory cytokines were measured. The chemical characterization of the material indicated the presence of drug associated with the coordination network in a proportion of 0.82 g 5-FU per 1.0 g of Cu-BTC MOF. The cytotoxic tests were carried out against four cell lines: NCI-H292, MCF-7, HT29 and HL60. The Cu-BTC MOF associated drug was extremely cytotoxic against the human breast cancer adenocarcinoma (MCF-7) cell line and against human acute promyelocytic leukemia cells (HL60), cancer cells were killed by apoptosis mechanisms. The drug demonstrated a slow release profile where 82% of the drug was released in 48 hours. The results indicated that the drug incorporated in Cu-BTC MOF decreased significantly the number of leukocytes in the peritoneal cavity of rodents as well as reduced levels of cytokines and nitric oxide production. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Spin Polarization and Quantum Spins in Au Nanoparticles

PubMed Central

Li, Chi-Yen; Karna, Sunil K.; Wang, Chin-Wei; Li, Wen-Hsien

2013-01-01

The present study focuses on investigating the magnetic properties and the critical particle size for developing sizable spontaneous magnetic moment of bare Au nanoparticles. Seven sets of bare Au nanoparticle assemblies, with diameters from 3.5 to 17.5 nm, were fabricated with the gas condensation method. Line profiles of the X-ray diffraction peaks were used to determine the mean particle diameters and size distributions of the nanoparticle assemblies. The magnetization curves M(Ha) reveal Langevin field profiles. Magnetic hysteresis was clearly revealed in the low field regime even at 300 K. Contributions to the magnetization from different size particles in the nanoparticle assemblies were considered when analyzing the M(Ha) curves. The results show that the maximum particle moment will appear in 2.4 nm Au particles. A similar result of the maximum saturation magnetization appearing in 2.3 nm Au particles is also concluded through analysis of the dependency of the saturation magnetization MP on particle size. The MP(d) curve departs significantly from the 1/d dependence, but can be described by a log-normal function. Magnetization can be barely detected for Au particles larger than 27 nm. Magnetic field induced Zeeman magnetization from the quantum confined Kubo gap opening appears in Au nanoparticles smaller than 9.5 nm in diameter. PMID:23989607

On beam shaping of the field radiated by a line source coupled to finite or infinite photonic crystals.

PubMed

Ceccuzzi, Silvio; Jandieri, Vakhtang; Baccarelli, Paolo; Ponti, Cristina; Schettini, Giuseppe

2016-04-01

Comparison of the beam-shaping effect of a field radiated by a line source, when an ideal infinite structure constituted by two photonic crystals and an actual finite one are considered, has been carried out by means of two different methods. The lattice sums technique combined with the generalized reflection matrix method is used to rigorously investigate the radiation from the infinite photonic crystals, whereas radiation from crystals composed of a finite number of rods along the layers is analyzed using the cylindrical-wave approach. A directive radiation is observed with the line source embedded in the structure. With an increased separation distance between the crystals, a significant edge diffraction appears that provides the main radiation mechanism in the finite layout. Suitable absorbers are implemented to reduce the above-mentioned diffraction and the reflections at the boundaries, thus obtaining good agreement between radiation patterns of a localized line source coupled to finite and infinite photonic crystals, when the number of periods of the finite structure is properly chosen.

The inference of vector magnetic fields from polarization measurements with limited spectral resolution

NASA Technical Reports Server (NTRS)

Lites, B. W.; Skumanich, A.

1985-01-01

A method is presented for recovery of the vector magnetic field and thermodynamic parameters from polarization measurement of photospheric line profiles measured with filtergraphs. The method includes magneto-optic effects and may be utilized on data sampled at arbitrary wavelengths within the line profile. The accuracy of this method is explored through inversion of synthetic Stokes profiles subjected to varying levels of random noise, instrumental wave-length resolution, and line profile sampling. The level of error introduced by the systematic effect of profile sampling over a finite fraction of the 5 minute oscillation cycle is also investigated. The results presented here are intended to guide instrumental design and observational procedure.

Fabrication of high-resolution x-ray diffractive optics at King's College London

NASA Astrophysics Data System (ADS)

Charalambous, Pambos S.; Anastasi, Peter A. F.; Burge, Ronald E.; Popova, Katia

1995-09-01

The fabrication of high resolution x-ray diffractive optics, and Fresnel zone plates (ZPs) in particular, is a very demanding multifaceted technological task. The commissioning of more (and brighter) synchrotron radiation sources, has increased the number of x-ray imaging beam lines world wide. The availability of cheaper and more effective laboratory x-ray sources, has further increased the number of laboratories involved in x-ray imaging. The result is an ever increasing demand for x-ray optics with a very wide range of specifications, reflecting the particular type of x-ray imaging performed at different laboratories. We have been involved in all aspects of high resolution nanofabrication for a number of years, and we have explored many different methods of lithography, which, although unorthodox, open up possibilities, and increase our flexibility for the fabrication of different diffractive optical elements, as well as other types of nanostructures. The availability of brighter x-ray sources, means that the diffraction efficiency of the ZPs is becoming of secondary importance, a trend which will continue in the future. Resolution, however, is important and will always remain so. Resolution is directly related to the accuracy af pattern generation, as well as the ability to draw fine lines. This is the area towards which we have directed most of our efforts so far.

X-Ray Diffraction and Imaging Study of Imperfections of Crystallized Lysozyme with Coherent X-Rays

NASA Technical Reports Server (NTRS)

Hu, Zheng-Wei; Chu, Y. S.; Lai, B.; Cai, Z.; Thomas, B. R.; Chernov, A. A.

2003-01-01

Phase-sensitive x-ray diffraction imaging and high angular-resolution diffraction combined with phase contrast radiographic imaging are employed to characterize defects and perfection of a uniformly grown tetragonal lysozyme crystal in symmetric Laue case. The fill width at half-maximum (FWHM) of a 4 4 0 rocking curve measured from the original crystal is approximately 16.7 arcseconds, and defects, which include point defects, line defects, and microscopic domains, have been clearly observed in the diffraction images of the crystal. The observed line defects carry distinct dislocation features running approximately along the <110> growth front, and they have been found to originate mostly at a central growth area and occasionally at outer growth regions. Individual point defects trapped at a crystal nucleus are resolved in the images of high sensitivity to defects. Slow dehydration has led to the broadening of the 4 4 0 rocking curve by a factor of approximately 2.4. A significant change of the defect structure and configuration with drying has been revealed, which suggests the dehydration induced migration and evolution of dislocations and lattice rearrangements to reduce overall strain energy. The sufficient details of the observed defects shed light upon perfection, nucleation and growth, and properties of protein crystals.

Notes and Discussion

ERIC Educational Resources Information Center

American Journal of Physics, 1978

1978-01-01

Describes experiments demonstrating the Josephson effect, single-file diffusion in biological membranes, refractive index of beer, lines of magnetic fields, indexing diffraction patterns, Maxwell's equations, and spherical aberration. (SL)

Derivation of the physical parameters for strong and weak flares from the Hα line

NASA Astrophysics Data System (ADS)

Semeida, M. A.; Rashed, M. G.

2016-06-01

The two flares of 19 and 30 July 1999 were observed in the Hα line using the multichannel flare spectrograph (MFS) at the Astronomical Institute in Ondřejov, Czech Republic. We use a modified cloud method to fit the Hα line profiles which avoids using the background profile. We obtain the four parameters of the two flares: the source function, the optical thickness at line center, the line-of-sight velocity and the Doppler width. The observed asymmetry profiles have been reproduced by the theoretical ones based on our model. A discussion is made about the results of strong and weak flares using the present method.

Thermal and temporal evolution of microstructure in polycrystalline ZnO

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kondal, Neha; Tiwari, Sanjiv Kumar, E-mail: sanjivkumar.tiwari@juit.ac.in

2016-05-06

Tug between electronics and spintronics has opened up new area of research named as dilute magnetic semiconductors (DMS), ZnO is one of the most reliable candidates for spintronic devices and DMS. Since, pure and transition metal doped polycrystalline ZnO shows room temperature ferromagnetism, therefore it is very important to gain insight into its microstructure (MS) evolution. We report thermal evolution of MS of pure ZnO on sintering it at 200 °C, 400 °C, 600 °C, and 800 °C in ambient atmosphere for two hours. Temporal evolution at fixed temperature was analyzed using mean field model of internal energy and entropy.more » Grain size of ZnO MS were analyzed using integral breadth method of X-ray diffraction (XRD) lines using Voigt profile fit,. XRD line corresponding to [101] plane shifts from 36.17° to 36.28° whereas grain size increases from 67.5 nm to 93.7 nm with increase of temperature from 23°C to 800°C respectively. Grain growth with increase of temperature show Arrhenius type behavior with activation energy of 30.77 kJ-mol{sup −1} and temporal growth shows diffusive behavior with exponent 0.5.« less

Release behavior and toxicity profiles towards A549 cell lines of ciprofloxacin from its layered zinc hydroxide intercalation compound.

PubMed

Abdul Latip, Ahmad Faiz; Hussein, Mohd Zobir; Stanslas, Johnson; Wong, Charng Choon; Adnan, Rohana

2013-01-01

Layered hydroxides salts (LHS), a layered inorganic compound is gaining attention in a wide range of applications, particularly due to its unique anion exchange properties. In this work, layered zinc hydroxide nitrate (LZH), a family member of LHS was intercalated with anionic ciprofloxacin (CFX), a broad spectrum antibiotic via ion exchange in a mixture solution of water:ethanol. Powder x-ray diffraction (XRD), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA) confirmed the drug anions were successfully intercalated in the interlayer space of LZH. Specific surface area of the obtained compound was increased compared to that of the host due to the different pore textures between the two materials. CFX anions were slowly released over 80 hours in phosphate-buffered saline (PBS) solution due to strong interactions that occurred between the intercalated anions and the host lattices. The intercalation compound demonstrated enhanced antiproliferative effects towards A549 cancer cells compared to the toxicity of CFX alone. Strong host-guest interactions between the LZH lattice and the CFX anion give rise to a new intercalation compound that demonstrates sustained release mode and enhanced toxicity effects towards A549 cell lines. These findings should serve as foundations towards further developments of the brucite-like host material in drug delivery systems.

IONIZED GAS KINEMATICS AT HIGH RESOLUTION. V. [Ne ii], MULTIPLE CLUSTERS, HIGH EFFICIENCY STAR FORMATION, AND BLUE FLOWS IN HE 2–10

DOE Office of Scientific and Technical Information (OSTI.GOV)

Beck, Sara; Turner, Jean; Lacy, John

2015-11-20

We measured the 12.8 μm [Ne ii] line in the dwarf starburst galaxy He 2–10 with the high-resolution spectrometer TEXES on the NASA IRTF. The data cube has a diffraction-limited spatial resolution of ∼1″ and a total velocity resolution, including thermal broadening, of ∼5 km s{sup −1}. This makes it possible to compare the kinematics of individual star-forming clumps and molecular clouds in the three dimensions of space and velocity, and allows us to determine star formation efficiencies. The kinematics of the ionized gas confirm that the starburst contains multiple dense clusters. From the M/R of the clusters and themore » ≃30%–40% star formation efficiencies, the clusters are likely to be bound and long lived, like globulars. Non-gravitational features in the line profiles show how the ionized gas flows through the ambient molecular material, as well as a narrow velocity feature, which we identify with the interface of the H ii region and a cold dense clump. These data offer an unprecedented view of the interaction of embedded H ii regions with their environment.« less

Interferometric investigation of emission lines from the solar corona

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marshall, P.M.; Henderson, G.

1973-11-01

The profiles of the Fe XN, lambda 5303, and Fe X, lambda 6374, emission lines of the solar corona were observed at different posttions using a photoelectric scanning Fabry -- Perot interferometer. These profiles were obtained during the eclipse of 7th March 1970, in Mexico and at the Pic-du-Midi coronagraph in October, 1970. The half-widths of these profiles were determined for both the coronal lines and temperatures were derived from these widths. No systematic temperature variation was discovered, however there was some suggestion of the existence of a fluctuation with time in the width of the emission lines. (auth)

X-RAY EMISSION LINE PROFILES FROM WIND CLUMP BOW SHOCKS IN MASSIVE STARS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ignace, R.; Waldron, W. L.; Cassinelli, J. P.

2012-05-01

The consequences of structured flows continue to be a pressing topic in relating spectral data to physical processes occurring in massive star winds. In a preceding paper, our group reported on hydrodynamic simulations of hypersonic flow past a rigid spherical clump to explore the structure of bow shocks that can form around wind clumps. Here we report on profiles of emission lines that arise from such bow shock morphologies. To compute emission line profiles, we adopt a two-component flow structure of wind and clumps using two 'beta' velocity laws. While individual bow shocks tend to generate double-horned emission line profiles,more » a group of bow shocks can lead to line profiles with a range of shapes with blueshifted peak emission that depends on the degree of X-ray photoabsorption by the interclump wind medium, the number of clump structures in the flow, and the radial distribution of the clumps. Using the two beta law prescription, the theoretical emission measure and temperature distribution throughout the wind can be derived. The emission measure tends to be power law, and the temperature distribution is broad in terms of wind velocity. Although restricted to the case of adiabatic cooling, our models highlight the influence of bow shock effects for hot plasma temperature and emission measure distributions in stellar winds and their impact on X-ray line profile shapes. Previous models have focused on geometrical considerations of the clumps and their distribution in the wind. Our results represent the first time that the temperature distribution of wind clump structures are explicitly and self-consistently accounted for in modeling X-ray line profile shapes for massive stars.« less

Modelling supernova line profile asymmetries to determine ejecta dust masses: SN 1987A from days 714 to 3604

NASA Astrophysics Data System (ADS)

Bevan, Antonia; Barlow, M. J.

2016-02-01

The late-time optical and near-IR line profiles of many core-collapse supernovae exhibit a red-blue asymmetry as a result of greater extinction by internal dust of radiation emitted from the receding parts of the supernova ejecta. We present here a new code, DAMOCLES, that models the effects of dust on the line profiles of core-collapse supernovae in order to determine newly formed dust masses. We find that late-time dust-affected line profiles may exhibit an extended red scattering wing (as noted by Lucy et al. 1989) and that they need not be flux-biased towards the blue, although the profile peak will always be blueshifted. We have collated optical spectra of SN 1987A from a variety of archival sources and have modelled the Hα line from days 714 to 3604 and the [O I] 6300,6363 Å doublet between days 714 and 1478. Our line profile fits rule out day 714 dust masses >3 × 10-3 M⊙ for all grain types apart from pure magnesium silicates, for which no more than 0.07 M⊙ can be accommodated. Large grain radii ( ≥ 0.6 μm) are generally required to fit the line profiles even at the earlier epochs. We find that a large dust mass (≥0.1 M⊙) had formed by day 3604 and infer that the majority of the present dust mass must have formed after this epoch. Our findings agree with recent estimates from spectral energy distribution fits for the dust mass evolution of SN 1987A and support the inference that the majority of SN 1987A's dust formed many years after the initial explosion.

Sodium D-line emission from Io - Comparison of observed and theoretical line profiles

NASA Technical Reports Server (NTRS)

Carlson, R. W.; Matson, D. L.; Johnson, T. V.; Bergstralh, J. T.

1978-01-01

High-resolution spectra of the D-line profiles have been obtained for Io's sodium emission cloud. These lines, which are produced through resonance scattering of sunlight, are broad and asymmetric and can be used to infer source and dynamical properties of the sodium cloud. In this paper we compare line profile data with theoretical line shapes computed for several assumed initial velocity distributions corresponding to various source mechanisms. We also examine the consequences of source distributions which are nonuniform over the surface of Io. It is found that the experimental data are compatible with escape of sodium atoms from the leading hemisphere of Io and with velocity distributions characteristic of sputtering processes. Thermal escape and simple models of plasma sweeping are found to be incompatible with the observations.

On VI /lambda equals 1032 A/ profiles in and above an active region prominence, compared to quiet sun center and limb profiles

NASA Astrophysics Data System (ADS)

Vial, J. C.; Lemaire, P.; Artzner, G.; Gouttebroze, P.

1980-11-01

O VI (λ = 1032 Å) profiles have been measured in and above a filament at the limb, previously analyzed in H I, Mg II, Ca II resonance lines (Vial et al., 1979). They are compared to profiles measured at the quiet Sun center and at the quiet Sun limb. Absolute intensities are found to be about 1.55 times larger than above the quiet limb at the same height (3"); at the top of the prominence (15" above the limb) one finds a maximum blue shift and a minimum line width. The inferred non-thermal velocity (29 km s-1) is about the same as in cooler lines while the approaching line-of-sight velocity (8 km s-1) is lower than in Ca II lines. The O VI profile recorded 30" above the limb outside the filament is wider (FWHM 0.33 Å). It can be interpreted as a coronal emission of 0 VI ions with a temperature of about 106 K, and a non-thermal velocity (NTV) of 49 km s-1. This NTV is twice the NTV of quiet Sun center O VI profiles. Lower NTV require higher temperatures and densities (as suggested by K-coronameter measurements). Computed emission measures for this high temperature regime agree with determinations from disk intensities of EUV lines.

Super resolution terahertz imaging by subpixel estimation: application to hyperspectral beam profiling

NASA Astrophysics Data System (ADS)

Logofătu, Petre C.; Damian, Victor

2018-05-01

A super-resolution terahertz imaging technique based on subpixel estimation was applied to hyperspectral beam profiling. The topic of hyperspectral beam profiling was chosen because the beam profile and its dependence on wavelength are not well known and are important for imaging applications. Super-resolution is required here to avoid diffraction effects and to provide a stronger signal. Super-resolution usually adds supplementary information to the measurement, but in this case, it is a prerequisite for it. We report that the beam profile is almost Gaussian for many frequencies; the waist of the Gaussian profile increases with frequency while the center wobbles slightly. Knowledge of the beam profile may subsequently be used as reference for imaging.

Long-Wavelength X-Ray Diffraction and Its Applications in Macromolecular Crystallography.

PubMed

Weiss, Manfred S

2017-01-01

For many years, diffraction experiments in macromolecular crystallography at X-ray wavelengths longer than that of Cu-K α (1.54 Å) have been largely underappreciated. Effects caused by increased X-ray absorption result in the fact that these experiments are more difficult than the standard diffraction experiments at short wavelengths. However, due to the also increased anomalous scattering of many biologically relevant atoms, important additional structural information can be obtained. This information, in turn, can be used for phase determination, for substructure identification, in molecular replacement approaches, as well as in structure refinement. This chapter reviews the possibilities and the difficulties associated with such experiments, and it provides a short description of two macromolecular crystallography synchrotron beam lines dedicated to long-wavelength X-ray diffraction experiments.

RSpec: New Real-time Spectroscopy Software Enhances High School and College Learning

NASA Astrophysics Data System (ADS)

Field, Tom

2011-01-01

Nothing beats hands-on experience! Students often have a more profound learning experience in a hands-on laboratory than in a classroom. However, development of inquiry-based curricula for teaching spectroscopy has been thwarted by the absence of affordable equipment. There is now a software program that brings the excitement of real-time spectroscopy into the lab. It eliminates the processing delays that accompany conventional after-the-fact data analysis -- delays that often result in sagging enthusiasm and loss of interest in young, active minds. RSpec is the ideal software for high school or undergraduate physics classes. It is a state-of-the-art, multi-threaded software program that allows students to observe spectral profile graphs and their colorful synthesized spectra in real-time video. Using an off-the-shelf webcam, DSLR, cooled-CCD or even a cell phone camera, students can now gain hands-on experience in gathering, calibrating, and identifying spectra. Light sources can include the sun, bright night-time astronomical objects, or gas tubes. Students can even build their own spectroscopes using inexpensive diffraction "rainbow” glasses. For more advanced students, the addition of an inexpensive slitless diffraction grating allows the study of even more exciting objects. With a modest 8” telescope, students can use a simple webcam to classify star types, and to detect such exciting phenomena as Neptune's methane-absorption lines, M42's emission lines, and even, believe it or not, the redshift of 3C 273. These adventures are possible even under light-polluted urban skies. RSpec is also an excellent program for amateur astronomers who want to transition from visual CCD imaging to actual scientific data collection and analysis. As the developer of this software, I worked with both teachers and experienced spectroscopists to ensure that it would bring a compelling experience to your students. The response to real-time, colorful data has been very enthusiastic both in the classroom and in public outreach.

High Dispersion Line Profile Studies of TW HYA and Other Pre-Main Sequence Stars

NASA Astrophysics Data System (ADS)

Linsky, Jeffrey L.

1984-07-01

We propose to extend our study of line profiles in T Tauri stars by obtaining a 16 hour SWP-HI spectrum of TW Hya and 6-8 hour LWP-HI spectra of TW Hya, AK Sco, CoD -35 10525 and CoD -33 10685. High dispersion spectra of pre-main sequence (PMS) stars provide unique information on line widths, shifts, and asymmetries, as well as evidence for mass outflow, circumstellar absorption, and diagnostics for the temperature structure of the outer atmosphere layers of these complex yet incredibly important objects. We have previously obtained and studied line profiles in RU Lupi and the prototype star T Tau. RU Lupi has line profiles that are dominated by the wind expansion, for example the MgII and FeII multiplet UV1 profiles are unique in that they have a classical P Cygni shape, whereas T Tau has more symmetric emission profiles indicative of a chromosphere and hotter layers not dominated by expansion. TW Hya is different from these two previously studied stars in that it may be the brightest known example of a post-T Tauri star, and hence less active and older than the other PMS stars. We intend to compare its line profiles with those of RU Lupi and T Tauri in order to understand the differences in the non-thermal mass motions, wind expansion, and thermal structures of these three very different T Tau stars. The requested LWPHI spectra are to obtain MgII and FeII multiplet UV1. profiles of 4 different T Tauri objects so as to infer the expansion and thermal structure in their chromospheric layers.

RADYN Simulations of Non-thermal and Thermal Models of Ellerman Bombs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hong, Jie; Ding, M. D.; Carlsson, Mats, E-mail: dmd@nju.edu.cn

Ellerman bombs (EBs) are brightenings in the H α line wings that are believed to be caused by magnetic reconnection in the lower atmosphere. To study the response and evolution of the chromospheric line profiles, we perform radiative hydrodynamic simulations of EBs using both non-thermal and thermal models. Overall, these models can generate line profiles that are similar to observations. However, in non-thermal models we find dimming in the H α line wings and continuum when the heating begins, while for the thermal models dimming occurs only in the H α line core, and with a longer lifetime. This differencemore » in line profiles can be used to determine whether an EB is dominated by non-thermal heating or thermal heating. In our simulations, if a higher heating rate is applied, then the H α line will be unrealistically strong and there are still no clear UV burst signatures.« less

RADYN Simulations of Non-thermal and Thermal Models of Ellerman Bombs

NASA Astrophysics Data System (ADS)

Hong, Jie; Carlsson, Mats; Ding, M. D.

2017-08-01

Ellerman bombs (EBs) are brightenings in the Hα line wings that are believed to be caused by magnetic reconnection in the lower atmosphere. To study the response and evolution of the chromospheric line profiles, we perform radiative hydrodynamic simulations of EBs using both non-thermal and thermal models. Overall, these models can generate line profiles that are similar to observations. However, in non-thermal models we find dimming in the Hα line wings and continuum when the heating begins, while for the thermal models dimming occurs only in the Hα line core, and with a longer lifetime. This difference in line profiles can be used to determine whether an EB is dominated by non-thermal heating or thermal heating. In our simulations, if a higher heating rate is applied, then the Hα line will be unrealistically strong and there are still no clear UV burst signatures.

Resolution of 90 nm (lambda/5) in an optical transmission microscope with an annular condenser.

PubMed

Vainrub, Arnold; Pustovyy, Oleg; Vodyanoy, Vitaly

2006-10-01

Resolution of 90 nm was achieved with a research microscope simply by replacing the standard bright-field condenser with a homebuilt illumination system with a cardioid annular condenser. Diffraction gratings with 100 nm width lines as well as less than 100 nm size features of different-shaped objects were clearly visible on a calibrated microscope test slide. The resolution increase results from a known narrower diffraction pattern in coherent illumination for the annular aperture compared with the circular aperture. This explanation is supported by an excellent accord of calculated and measured diffraction patterns for a 50 nm radius disk.

Inversions of synthetic umbral flashes: Effects of scanning time on the inferred atmospheres

NASA Astrophysics Data System (ADS)

Felipe, T.; Socas-Navarro, H.; Przybylski, D.

2018-06-01

Context. The use of instruments that record narrowband images at selected wavelengths is a common approach in solar observations. They allow scanning of a spectral line by sampling the Stokes profiles with two-dimensional images at each line position, but require a compromise between spectral resolution and temporal cadence. The interpretation and inversion of spectropolarimetric data generally neglect changes in the solar atmosphere during the scanning of line profiles. Aims: We evaluate the impact of the time-dependent acquisition of various wavelengths on the inversion of spectropolarimetric profiles from chromospheric lines during umbral flashes. Methods: Numerical simulations of nonlinear wave propagation in a sunspot model were performed with the code MANCHA. Synthetic Stokes parameters in the Ca II 8542 Å line in NLTE were computed for an umbral flash event using the code NICOLE. Artificial profiles with the same wavelength coverage and temporal cadence from reported observations were constructed and inverted. The inferred atmospheric stratifications were compared with the original simulated models. Results: The inferred atmospheres provide a reasonable characterization of the thermodynamic properties of the atmosphere during most of the phases of the umbral flash. The Stokes profiles present apparent wavelength shifts and other spurious deformations at the early stages of the flash, when the shock wave reaches the formation height of the Ca II 8542 Å line. These features are misinterpreted by the inversion code, which can return unrealistic atmospheric models from a good fit of the Stokes profiles. The misguided results include flashed atmospheres with strong downflows, even though the simulation exhibits upflows during the umbral flash, and large variations in the magnetic field strength. Conclusions: Our analyses validate the inversion of Stokes profiles acquired by sequentially scanning certain selected wavelengths of a line profile, even in the case of rapidly changing chromospheric events such as umbral flashes. However, the inversion results are unreliable during a short period at the development phase of the flash.

Mid-Atlantic multichannel seismic-reflection profiles 14, 15, 16, and 17

USGS Publications Warehouse

Schlee, John Stevens

1980-01-01

The U. S. Geological Survey (USGS) is making available four multi­channel profiles collected by Teledyne Exploration in 1977 by means of a 48-channel streamer (3600 m long) and four airguns (2160 in). Profiles 15 and 16 were processed by.Teledyne Exploration and profiles 14 and 17 were processed on the Phoenix "I"* computer·by the USGS. The processing included standard demultiplexing, deconvolution before and aftfer stack, Common Depth Point (CDP) gathers, velocity analyses every 3 km, move-out correction, stacking, time-variant, filtering, and time-variant scaling.The released lines are over the outer edge of the Continental Shelf in the northern part of the Baltimore Canyon trough (Line 14: 140 km long and Line 15: 157 km long), over the Long Island platform. (Line 16: 313 km long), and over the Carolina platform (Line 17: 186 km long). These profiles were collected as a part of a regional grid over offshore Atlantic sedimentary basins in a continuing program to assess the resource potential by means of nonproprietary data.These profiles, plus the velocity scans and shotpoint maps, may be viewed at U. S. Geological Survey, Quissett Campus, Woods Hole, MA. 02543, and U. S. Geological Survey, Bldg. 25, Denver Federal Center, Denver, CO. Copies of maps, scans, and profiles can be purchased only from the National Geophysical Solar-Terrestrial Data Center, Environmental Data Service (NOM), Code D 621, Boulder, CO 80302.

Laboratory measurements of white dwarf photospheric spectral lines: Hβ

DOE PAGES

Falcon, Ross Edward; Rochau, Gregory A.; Bailey, James E.; ...

2015-06-18

We spectroscopically measure multiple hydrogen Balmer line profiles from laboratory plasmas to investigate the theoretical line profiles used in white dwarf (WD) atmosphere models. X-ray radiation produced at the Z Pulsed Power Facility at Sandia National Laboratories initiates plasma formation in a hydrogen-filled gas cell, replicating WD photospheric conditions. We also present time-resolved measurements of Hβ and fit this line using different theoretical line profiles to diagnose electron density, n e, and n = 2 level population, n 2. Aided by synthetic tests, we characterize the validity of our diagnostic method for this experimental platform. During a single experiment, wemore » infer a continuous range of electron densities increasing from n e ~ 4 to ~30 × 10 16 cm -3 throughout a 120-ns evolution of our plasma. Also, we observe n 2 to be initially elevated with respect to local thermodynamic equilibrium (LTE); it then equilibrates within ~55 ns to become consistent with LTE. This also supports our electron-temperature determination of T e ~ 1.3 eV (~15,000 K) after this time. At n e≲ 10 17 cm -3, we find that computer-simulation-based line-profile calculations provide better fits (lower reduced χ 2) than the line profiles currently used in the WD astronomy community. The inferred conditions, however, are in good quantitative agreement. Lastly, this work establishes an experimental foundation for the future investigation of relative shapes and strengths between different hydrogen Balmer lines.« less

DNA methylation profiles of ovarian epithelial carcinoma tumors and cell lines.

PubMed

Houshdaran, Sahar; Hawley, Sarah; Palmer, Chana; Campan, Mihaela; Olsen, Mari N; Ventura, Aviva P; Knudsen, Beatrice S; Drescher, Charles W; Urban, Nicole D; Brown, Patrick O; Laird, Peter W

2010-02-22

Epithelial ovarian carcinoma is a significant cause of cancer mortality in women worldwide and in the United States. Epithelial ovarian cancer comprises several histological subtypes, each with distinct clinical and molecular characteristics. The natural history of this heterogeneous disease, including the cell types of origin, is poorly understood. This study applied recently developed methods for high-throughput DNA methylation profiling to characterize ovarian cancer cell lines and tumors, including representatives of three major histologies. We obtained DNA methylation profiles of 1,505 CpG sites (808 genes) in 27 primary epithelial ovarian tumors and 15 ovarian cancer cell lines. We found that the DNA methylation profiles of ovarian cancer cell lines were markedly different from those of primary ovarian tumors. Aggregate DNA methylation levels of the assayed CpG sites tended to be higher in ovarian cancer cell lines relative to ovarian tumors. Within the primary tumors, those of the same histological type were more alike in their methylation profiles than those of different subtypes. Supervised analyses identified 90 CpG sites (68 genes) that exhibited 'subtype-specific' DNA methylation patterns (FDR<1%) among the tumors. In ovarian cancer cell lines, we estimated that for at least 27% of analyzed autosomal CpG sites, increases in methylation were accompanied by decreases in transcription of the associated gene. The significant difference in DNA methylation profiles between ovarian cancer cell lines and tumors underscores the need to be cautious in using cell lines as tumor models for molecular studies of ovarian cancer and other cancers. Similarly, the distinct methylation profiles of the different histological types of ovarian tumors reinforces the need to treat the different histologies of ovarian cancer as different diseases, both clinically and in biomarker studies. These data provide a useful resource for future studies, including those of potential tumor progenitor cells, which may help illuminate the etiology and natural history of these cancers.

Fabricating Blazed Diffraction Gratings by X-Ray Lithography

NASA Technical Reports Server (NTRS)

Mouroulis, Pantazis; Hartley, Frank; Wilson, Daniel

2004-01-01

Gray-scale x-ray lithography is undergoing development as a technique for fabricating blazed diffraction gratings. As such, gray-scale x-ray lithography now complements such other grating-fabrication techniques as mechanical ruling, holography, ion etching, laser ablation, laser writing, and electron-beam lithography. Each of these techniques offers advantages and disadvantages for implementing specific grating designs; no single one of these techniques can satisfy the design requirements for all applications. Gray-scale x-ray lithography is expected to be advantageous for making gratings on steeper substrates than those that can be made by electron-beam lithography. This technique is not limited to sawtooth groove profiles and flat substrates: various groove profiles can be generated on arbitrarily shaped (including highly curved) substrates with the same ease as sawtooth profiles can be generated on flat substrates. Moreover, the gratings fabricated by this technique can be made free of ghosts (spurious diffraction components attributable to small spurious periodicities in the locations of grooves). The first step in gray-scale x-ray lithography is to conformally coat a substrate with a suitable photoresist. An x-ray mask (see Figure 1) is generated, placed between the substrate and a source of collimated x-rays, and scanned over the substrate so as to create a spatial modulation in the exposure of the photoresist. Development of the exposed photoresist results in a surface corrugation that corresponds to the spatial modulation and that defines the grating surface. The grating pattern is generated by scanning an appropriately shaped x-ray area mask along the substrate. The mask example of Figure 1 would generate a blazed grating profile when scanned in the perpendicular direction at constant speed, assuming the photoresist responds linearly to incident radiation. If the resist response is nonlinear, then the mask shape can be modified to account for the nonlinearity and produce a desired groove profile. An example of grating grooves generated by this technique is shown in Figure 2. A maximum relative efficiency of 88 percent has been demonstrated.

Serial single molecule electron diffraction imaging: diffraction background of superfluid helium droplets

NASA Astrophysics Data System (ADS)

Zhang, Jie; He, Yunteng; Lei, Lei; Alghamdi, Maha; Oswalt, Andrew; Kong, Wei

2017-08-01

In an effort to solve the crystallization problem in crystallography, we have been engaged in developing a method termed "serial single molecule electron diffraction imaging" (SS-EDI). The unique features of SS-EDI are superfluid helium droplet cooling and field-induced orientation: together the two features constitute a molecular goniometer. Unfortunately, the helium atoms surrounding the sample molecule also contribute to a diffraction background. In this report, we analyze the properties of a superfluid helium droplet beam and its doping statistics, and demonstrate the feasibility of overcoming the background issue by using the velocity slip phenomenon of a pulsed droplet beam. Electron diffraction profiles and pair correlation functions of ferrocene-monomer-doped droplets and iodine-nanocluster-doped droplets are presented. The timing of the pulsed electron gun and the effective doping efficiency under different dopant pressures can both be controlled for size selection. This work clears any doubt of the effectiveness of superfluid helium droplets in SS-EDI, thereby advancing the effort in demonstrating the "proof-of-concept" one step further.

Stacking fault density and bond orientational order of fcc ruthenium nanoparticles

NASA Astrophysics Data System (ADS)

Seo, Okkyun; Sakata, Osami; Kim, Jae Myung; Hiroi, Satoshi; Song, Chulho; Kumara, Loku Singgappulige Rosantha; Ohara, Koji; Dekura, Shun; Kusada, Kohei; Kobayashi, Hirokazu; Kitagawa, Hiroshi

2017-12-01

We investigated crystal structure deviations of catalytic nanoparticles (NPs) using synchrotron powder X-ray diffraction. The samples were fcc ruthenium (Ru) NPs with diameters of 2.4, 3.5, 3.9, and 5.4 nm. We analyzed average crystal structures by applying the line profile method to a stacking fault model and local crystal structures using bond orientational order (BOO) parameters. The reflection peaks shifted depending on rules that apply to each stacking fault. We evaluated the quantitative stacking faults densities for fcc Ru NPs, and the stacking fault per number of layers was 2-4, which is quite large. Our analysis shows that the fcc Ru 2.4 nm-diameter NPs have a considerably high stacking fault density. The B factor tends to increase with the increasing stacking fault density. A structural parameter that we define from the BOO parameters exhibits a significant difference from the ideal value of the fcc structure. This indicates that the fcc Ru NPs are highly disordered.

Vacuum ultraviolet spectropolarimeter design for precise polarization measurements.

PubMed

Narukage, Noriyuki; Auchère, Frédéric; Ishikawa, Ryohko; Kano, Ryouhei; Tsuneta, Saku; Winebarger, Amy R; Kobayashi, Ken

2015-03-10

Precise polarization measurements in the vacuum ultraviolet (VUV) region provide a new means for inferring weak magnetic fields in the upper atmosphere of the Sun and stars. We propose a VUV spectropolarimeter design ideally suited for this purpose. This design is proposed and adopted for the NASA-JAXA chromospheric lyman-alpha spectropolarimeter (CLASP), which will record the linear polarization (Stokes Q and U) of the hydrogen Lyman-α line (121.567 nm) profile. The expected degree of polarization is on the order of 0.1%. Our spectropolarimeter has two optically symmetric channels to simultaneously measure orthogonal linear polarization states with a single concave diffraction grating that serves both as the spectral dispersion element and beam splitter. This design has a minimal number of reflective components with a high VUV throughput. Consequently, these design features allow us to minimize the polarization errors caused by possible time variation of the VUV flux during the polarization modulation and by statistical photon noise.

Validity of "sputtering and re-condensation" model in active screen cage plasma nitriding process

NASA Astrophysics Data System (ADS)

Saeed, A.; Khan, A. W.; Jan, F.; Abrar, M.; Khalid, M.; Zakaullah, M.

2013-05-01

The validity of "sputtering and re-condensation" model in active screen plasma nitriding for nitrogen mass transfer mechanism is investigated. The dominant species including NH, Fe-I, N2+, N-I and N2 along with Hα and Hβ lines are observed in the optical emission spectroscopy (OES) analysis. Active screen cage and dc plasma nitriding of AISI 316 stainless steel as function of treatment time is also investigated. The structure and phases composition of the nitrided layer is studied by X-ray diffraction (XRD). Surface morphology is studied by scanning electron microscopy (SEM) and hardness profile is obtained by Vicker's microhardness tester. Increasing trend in microhardness is observed in both cases but the increase in active screen plasma nitriding is about 3 times greater than that achieved by dc plasma nitriding. On the basis of metallurgical and OES observations the use of "sputtering and re-condensation" model in active screen plasma nitriding is tested.

OBSERVATIONS AND SIMULATIONS OF THE Na i D{sub 1} LINE PROFILES IN AN M-CLASS SOLAR FLARE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuridze, D.; Mathioudakis, M.; Jess, D. B.

2016-12-01

We study the temporal evolution of the Na i D{sub 1} line profiles in the M3.9 flare SOL2014-06-11T21:03 UT, using observations at high spectral resolution obtained with the Interferometric Bidimensional Spectrometer instrument on the Dunn Solar Telescope combined with radiative hydrodynamic simulations. Our results show a significant increase in the intensities of the line core and wings during the flare. The analysis of the line profiles from the flare ribbons reveals that the Na i D{sub 1} line has a central reversal with excess emission in the blue wing (blue asymmetry). We combine RADYN and RH simulations to synthesize Na imore » D{sub 1} line profiles of the flaring atmosphere and find good agreement with the observations. Heating with a beam of electrons modifies the radiation field in the flaring atmosphere and excites electrons from the ground state 3s {sup 2}S to the first excited state 3p {sup 2}P, which in turn modifies the relative population of the two states. The change in temperature and the population density of the energy states make the sodium line profile revert from absorption into emission. Furthermore, the rapid changes in temperature break the pressure balance between the different layers of the lower atmosphere, generating upflow/downflow patterns. Analysis of the simulated spectra reveals that the asymmetries of the Na i D{sub 1} flare profile are produced by the velocity gradients in the lower solar atmosphere.« less

High pressure effects on U L 3 x-ray absorption in partial fluorescence yield mode and single crystal x-ray diffraction in the heavy fermion compound UCd 11

DOE PAGES

Nasreen, Farzana; Antonio, Daniel; VanGennep, Derrick; ...

2016-02-15

© 2016 IOP Publishing Ltd. We report a study of high pressure x-ray absorption (XAS) performed in the partial fluorescence yield mode (PFY) at the U L 3 edge (0-28.2 GPa) and single crystal x-ray diffraction (SXD) (0-20 GPa) on the UCd 11 heavy fermion compound at room temperature. Under compression, the PFY-XAS results show that the white line is shifted by +4.1(3) eV at the highest applied pressure of 28.2 GPa indicating delocalization of the 5f electrons. The increase in full width at half maxima and decrease in relative amplitude of the white line with respect to the edgemore » jump point towards 6d band broadening under high pressure. A bulk modulus of K 0 = 62(1) GPa and its pressure derivative, = 4.9(2) was determined from high pressure SXD results. Both the PFY-XAS and diffraction results do not show any sign of a structural phase transition in the applied pressure range.« less

Fast integral methods for integrated optical systems simulations: a review

NASA Astrophysics Data System (ADS)

Kleemann, Bernd H.

2015-09-01

Boundary integral equation methods (BIM) or simply integral methods (IM) in the context of optical design and simulation are rigorous electromagnetic methods solving Helmholtz or Maxwell equations on the boundary (surface or interface of the structures between two materials) for scattering or/and diffraction purposes. This work is mainly restricted to integral methods for diffracting structures such as gratings, kinoforms, diffractive optical elements (DOEs), micro Fresnel lenses, computer generated holograms (CGHs), holographic or digital phase holograms, periodic lithographic structures, and the like. In most cases all of the mentioned structures have dimensions of thousands of wavelengths in diameter. Therefore, the basic methods necessary for the numerical treatment are locally applied electromagnetic grating diffraction algorithms. Interestingly, integral methods belong to the first electromagnetic methods investigated for grating diffraction. The development started in the mid 1960ies for gratings with infinite conductivity and it was mainly due to the good convergence of the integral methods especially for TM polarization. The first integral equation methods (IEM) for finite conductivity were the methods by D. Maystre at Fresnel Institute in Marseille: in 1972/74 for dielectric, and metallic gratings, and later for multiprofile, and other types of gratings and for photonic crystals. Other methods such as differential and modal methods suffered from unstable behaviour and slow convergence compared to BIMs for metallic gratings in TM polarization from the beginning to the mid 1990ies. The first BIM for gratings using a parametrization of the profile was developed at Karl-Weierstrass Institute in Berlin under a contract with Carl Zeiss Jena works in 1984-1986 by A. Pomp, J. Creutziger, and the author. Due to the parametrization, this method was able to deal with any kind of surface grating from the beginning: whether profiles with edges, overhanging non-functional profiles, very deep ones, very large ones compared to wavelength, or simple smooth profiles. This integral method with either trigonometric or spline collocation, iterative solver with O(N2) complexity, named IESMP, was significantly improved by an efficient mesh refinement, matrix preconditioning, Ewald summation method, and an exponentially convergent quadrature in 2006 by G. Schmidt and A. Rathsfeld from Weierstrass-Institute (WIAS) Berlin. The so-called modified integral method (MIM) is a modification of the IEM of D. Maystre and has been introduced by L. Goray in 1995. It has been improved for weak convergence problems in 2001 and it was the only commercial available integral method for a long time, known as PCGRATE. All referenced integral methods so far are for in-plane diffraction only, no conical diffraction was possible. The first integral method for gratings in conical mounting was developed and proven under very weak conditions by G. Schmidt (WIAS) in 2010. It works for separated interfaces and for inclusions as well as for interpenetrating interfaces and for a large number of thin and thick layers in the same stable way. This very fast method has then been implemented for parallel processing under Unix and Windows operating systems. This work gives an overview over the most important BIMs for grating diffraction. It starts by presenting the historical evolution of the methods, highlights their advantages and differences, and gives insight into new approaches and their achievements. It addresses future open challenges at the end.

Establishment and Biological Characterization of a Panel of Glioblastoma Multiforme (GBM) and GBM Variant Oncosphere Cell Lines.

PubMed

Binder, Zev A; Wilson, Kelli M; Salmasi, Vafi; Orr, Brent A; Eberhart, Charles G; Siu, I-Mei; Lim, Michael; Weingart, Jon D; Quinones-Hinojosa, Alfredo; Bettegowda, Chetan; Kassam, Amin B; Olivi, Alessandro; Brem, Henry; Riggins, Gregory J; Gallia, Gary L

2016-01-01

Human tumor cell lines form the basis of the majority of present day laboratory cancer research. These models are vital to studying the molecular biology of tumors and preclinical testing of new therapies. When compared to traditional adherent cell lines, suspension cell lines recapitulate the genetic profiles and histologic features of glioblastoma multiforme (GBM) with higher fidelity. Using a modified neural stem cell culture technique, here we report the characterization of GBM cell lines including GBM variants. Tumor tissue samples were obtained intra-operatively and cultured in neural stem cell conditions containing growth factors. Tumor lines were characterized in vitro using differentiation assays followed by immunostaining for lineage-specific markers. In vivo tumor formation was assayed by orthotopic injection in nude mice. Genetic uniqueness was confirmed via short tandem repeat (STR) DNA profiling. Thirteen oncosphere lines derived from GBM and GBM variants, including a GBM with PNET features and a GBM with oligodendroglioma component, were established. All unique lines showed distinct genetic profiles by STR profiling. The lines assayed demonstrated a range of in vitro growth rates. Multipotency was confirmed using in vitro differentiation. Tumor formation demonstrated histologic features consistent with high grade gliomas, including invasion, necrosis, abnormal vascularization, and high mitotic rate. Xenografts derived from the GBM variants maintained histopathological features of the primary tumors. We have generated and characterized GBM suspension lines derived from patients with GBMs and GBM variants. These oncosphere cell lines will expand the resources available for preclinical study.

An Explanation of Remarkable Emission-line Profiles in Post-flare Coronal Rain

NASA Astrophysics Data System (ADS)

Lacatus, Daniela A.; Judge, Philip G.; Donea, Alina

2017-06-01

We study broad redshifted emission in chromospheric and transition region lines that appears to correspond to a form of post-flare coronal rain. Profiles of Mg II, C II, and Si IV lines were obtained using IRIS before, during, and after the X2.1 flare of 2015 March 11 (SOL2015-03-11T16:22). We analyze the profiles of the five transitions of Mg II (the 3p-3s h and k transitions, and three lines belonging to the 3d-3p transitions). We use analytical methods to understand the unusual profiles, together with higher-resolution observational data of similar phenomena observed by Jing et al. The peculiar line ratios indicate anisotropic emission from the strands that have cross-strand line center optical depths (k line) of between 1 and 10. The lines are broadened by unresolved Alfvénic motions whose energy exceeds the radiation losses in the Mg II lines by an order of magnitude. The decay of the line widths is accompanied by a decay in the brightness, suggesting a causal connection. If the plasma is ≲99% ionized, ion-neutral collisions can account for the dissipation; otherwise, a dynamical process seems necessary. Our work implies that the motions are initiated during the impulsive phase, to be dissipated as radiation over a period of an hour, predominantly by strong chromospheric lines. The coronal “rain” we observe is far more turbulent than most earlier reports have indicated, with implications for plasma heating mechanisms.

Kinetic Energy Distribution of D(2p) Atoms From Analysis of the D Lyman-a Line Profile

NASA Technical Reports Server (NTRS)

Ciocca, Marco; Ajello, Joseph M.; Liu, Xianming; Maki, Justin

1997-01-01

The absolute cross sections of the line center (slow atoms) and wings (fast atoms) and total emission line profile were measured from threshold to 400 eV. Analytical model coeffiecients are given for the energy dependence of the measured slow atom cross section.

Time scale variation of NV resonance line profiles of HD203064

NASA Astrophysics Data System (ADS)

Strantzalis, A.

2012-01-01

Hot emission star, such as Be and Oe, present many spectral lines with very complex and peculiar profiles. Therefore, we cannot find a classical distribution to fit theoretically those physical line profiles. So, many physical parameters of the regions, where spectral lines are created, are difficult to estimate. Here, in this poster paper we study the UV NV (λλ 1238.821, 1242.804 A) resonance lines of the Be star HD203064 at three different dates. We using the Gauss-Rotation model, that proposed the idea that these complex profiles consist of a number of independent Discrete or Satellite Absorption Components (DACs, SACs). Our purpose is to calculate the values of a group of physical parameters as the apparent rotational, radial, and random velocities of the thermal motions of the ions. Also the Full Width at Half Maximum (FWHM) and the column density, as well as the absorbed energy of the independent regions of matter, which produce the main and the satellite components of the studied spectral lines. In addition, we determine the time scale variations of the above physical parameters.

Diffractive optical element-based glossmeter for the on-line measurement of normal reflectance on a printed porous coated paper

NASA Astrophysics Data System (ADS)

Oksman, Antti; Kuivalainen, Kalle; Ta˚G, Carl-Mikael; Juuti, Mikko; Mattila, Rauno; Hietala, Eero; Gane, Patrick A. C.; Peiponen, Kai-Erik

2011-04-01

Gloss of a product, such as print gloss, is mainly inspected with conventional white light glossmeters both at laboratory or production facilities. However, problems occur in conventional gloss measurement when the inspected surface is vertically moved in the plane of incidence and reflection or when the measurement area is small or curved. For a partial solution to these problems, we have previously introduced diffractive optical element-based glossmeters (DOGs) for the gloss inspection in laboratories and off-line use. We present a new construction of DOG, termed μDOG 1D, for the one-dimensional on-line print gloss measurement, in the form of the reflectance determination normal to the surface. The function of the glossmeter is demonstrated by laboratory tests and on-line measurements at a heat-set web offset printing machine. It is shown that gloss (i.e., normal reflectance) and minute gloss variation of papers and prints can be measured at the printing line using the glossmeter. This glossmeter is expected to be useful in real-time monitoring of the gloss and surface-specific absorption not only in the printing industry but also in inspection of products in other industrial sectors, such as metal finishing, laminating, paper, and construction materials manufacturing.

Refraction effects in soft x-ray multilayer blazed gratings.

PubMed

Voronov, D L; Salmassi, F; Meyer-Ilse, J; Gullikson, E M; Warwick, T; Padmore, H A

2016-05-30

A 2500 lines/mm Multilayer Blazed Grating (MBG) optimized for the soft x-ray wavelength range was fabricated and tested. The grating coated with a W/B₄C multilayer demonstrated a record diffraction efficiency in the 2nd blazed diffraction order in the energy range from 500 to 1200 eV. Detailed investigation of the diffraction properties of the grating demonstrated that the diffraction efficiency of high groove density MBGs is not limited by the normal shadowing effects that limits grazing incidence x-ray grating performance. Refraction effects inherent in asymmetrical Bragg diffraction were experimentally confirmed for MBGs. The refraction affects the blazing properties of the MBGs and results in a shift of the resonance wavelength of the gratings and broadening or narrowing of the grating bandwidth depending on diffraction geometry. The true blaze angle of the MBGs is defined by both the real structure of the multilayer stack and by asymmetrical refraction effects. Refraction effects can be used as a powerful tool in providing highly efficient suppression of high order harmonics.

Analysis of three-dimensional-cavity-backed aperture antennas using a Combined Finite Element Method/Method of Moments/Geometrical Theory of Diffraction technique

NASA Technical Reports Server (NTRS)

Reddy, C. J.; Deshpande, M. D.; Cockrell, C. R.; Beck, F. B.

1995-01-01

A combined finite element method (FEM) and method of moments (MoM) technique is presented to analyze the radiation characteristics of a cavity-fed aperture in three dimensions. Generalized feed modeling has been done using the modal expansion of fields in the feed structure. Numerical results for some feeding structures such as a rectangular waveguide, circular waveguide, and coaxial line are presented. The method also uses the geometrical theory of diffraction (GTD) to predict the effect of a finite ground plane on radiation characteristics. Input admittance calculations for open radiating structures such as a rectangular waveguide, a circular waveguide, and a coaxial line are shown. Numerical data for a coaxial-fed cavity with finite ground plane are verified with experimental data.

Measurement of the profile and intensity of the solar He I lambda 584-A resonance line

NASA Technical Reports Server (NTRS)

Maloy, J. O.; Hartmann, U. G.; Judge, D. L.; Carlson, R. W.

1978-01-01

The intensity and profile of the helium resonance line at 584 A from the entire disk of the sun was investigated by using a rocket-borne helium-filled spectrometer and a curve-of-growth technique. The line profile was found to be accurately represented by a Gaussian profile with full width at half maximum of 122 + or - 10 mA, while the integrated intensity was measured to be 2.6 + or - 1.3 billion photons/s per sq cm at solar activity levels of F(10.7) = 90.8 x 10 to the -22nd per sq m/Hz and Rz = 27. The measured line width is in good agreement with previous spectrographic measurements, but the integrated intensity is larger than most previous photoelectric measurements. However, the derived line center flux of 20 + or - 10 billion photons/s per sq cm/A is in good agreement with values inferred from airglow measurements.

Constraints on the outer radius of the broad emission line region of active galactic nuclei

NASA Astrophysics Data System (ADS)

Landt, Hermine; Ward, Martin J.; Elvis, Martin; Karovska, Margarita

2014-03-01

Here we present observational evidence that the broad emission line region (BELR) of active galactic nuclei (AGN) generally has an outer boundary. This was already clear for sources with an obvious transition between the broad and narrow components of their emission lines. We show that the narrow component of the higher-order Paschen lines is absent in all sources, revealing a broad emission line profile with a broad, flat top. This indicates that the BELR is kinematically separate from the narrow emission line region. We use the virial theorem to estimate the BELR outer radius from the flat top width of the unblended profiles of the strongest Paschen lines, Paα and Paβ, and find that it scales with the ionizing continuum luminosity roughly as expected from photoionization theory. The value of the incident continuum photon flux resulting from this relationship corresponds to that required for dust sublimation. A flat-topped broad emission line profile is produced by both a spherical gas distribution in orbital motion and an accretion disc wind if the ratio between the BELR outer and inner radius is assumed to be less than ˜100-200. On the other hand, a pure Keplerian disc can be largely excluded, since for most orientations and radial extents of the disc the emission line profile is double-horned.

HST FUV monitoring of TW Hya

NASA Astrophysics Data System (ADS)

Guenther, Hans; Brickhouse, N. S.; Dupree, A. K.; Luna, G.; Schneider, P. C.; Wolk, S. J.

2014-01-01

Classical T Tauri stars (CTTS) show strong, broad and asymmetric FUV emission lines. Neither the width, nor the line profile is understood. Likely, different mechanisms influence the line profile; the best candidates are accretion, winds and stellar activity. We monitored the C IV 1548/1550 Å doublet in the nearby, bright CTTS TW Hya to correlate it with i) the cool wind, as seen in COS NUV Mg II line profiles, ii) the photometric period from joint ground-based monitoring, iii) the accretion rate as determined from the UV continuum and iv) the Ha line profile from independent ground-based observations. The observations span 10 orbits distributed over a few weeks to cover the typical time scales of stellar rotation, accretion and winds. On short time scales (seconds) the variability in the data is compatible with counting statistics when we take certain instrumental effects (the detector dead-time fraction increases when the wavelength calibration lamps are switched on). This rules out any type of coherent accretion shock fluctuation as predicted in some simulations. On longer time scales (days) variability of a factor of 3 in the continuum and similarly massive changes in the line shape are seen. The ratio of the two lines of the doublet indicates that the lines are optically thick, calling into question the idea that the blue-shifted components of the C IV lines are formed in the pre-shock region.

X-ray Diffraction Investigation of Annealing Behavior of Peened Surface Deformation Layer on Precipitation Hardening Stainless Steel

NASA Astrophysics Data System (ADS)

Huang, Junjie; Wang, Zhou; Gan, Jin; Yang, Ying; Huang, Feng; Wu, Gang; Meng, Qingshuai

2018-05-01

In order to investigate the recrystallization behavior of peened surface deformation layer of precipitation hardening stainless steel, a classic x-ray diffraction line profile analysis, Voigt method, was carried out on peened 17-4PH with different isothermal annealing temperatures. The activation energy of domain boundary migration ( Q a) and the activation energy of microstrain relaxation ( Q b) were calculated by regression analysis in different annealing temperature conditions. The results show that the value of Q a decreases with annealing temperature increasing, which is due to the influence of precipitation (ɛ-Cu) size on the movements of grain and subgrain boundaries. The maximum growth rate of ɛ-Cu particles occurs during 400 to 500 °C interval. Compared with growth behavior of domain size, microstrain relaxation behavior is less sensitive to precipitation particle size. The effects of annealing temperature and time on dislocation density are both significant when annealing temperature is lower than 500 °C. However, the effect of annealing temperature on dislocation density becomes insignificant when annealing temperature is higher than 500 °C. 300 °C annealing temperature only leads to the microstrain relaxation but nearly cannot lead to the domain size growth even if prolonging annealing time. Microstructure enhancement effect still exists in plastic deformation layer when 300 °C annealing temperature lasts for 60 min but nearly disappears when 600 °C annealing temperature lasts for 20 min.

Adaptive optics retinal imaging in the living mouse eye

PubMed Central

Geng, Ying; Dubra, Alfredo; Yin, Lu; Merigan, William H.; Sharma, Robin; Libby, Richard T.; Williams, David R.

2012-01-01

Correction of the eye’s monochromatic aberrations using adaptive optics (AO) can improve the resolution of in vivo mouse retinal images [Biss et al., Opt. Lett. 32(6), 659 (2007) and Alt et al., Proc. SPIE 7550, 755019 (2010)], but previous attempts have been limited by poor spot quality in the Shack-Hartmann wavefront sensor (SHWS). Recent advances in mouse eye wavefront sensing using an adjustable focus beacon with an annular beam profile have improved the wavefront sensor spot quality [Geng et al., Biomed. Opt. Express 2(4), 717 (2011)], and we have incorporated them into a fluorescence adaptive optics scanning laser ophthalmoscope (AOSLO). The performance of the instrument was tested on the living mouse eye, and images of multiple retinal structures, including the photoreceptor mosaic, nerve fiber bundles, fine capillaries and fluorescently labeled ganglion cells were obtained. The in vivo transverse and axial resolutions of the fluorescence channel of the AOSLO were estimated from the full width half maximum (FWHM) of the line and point spread functions (LSF and PSF), and were found to be better than 0.79 μm ± 0.03 μm (STD)(45% wider than the diffraction limit) and 10.8 μm ± 0.7 μm (STD)(two times the diffraction limit), respectively. The axial positional accuracy was estimated to be 0.36 μm. This resolution and positional accuracy has allowed us to classify many ganglion cell types, such as bistratified ganglion cells, in vivo. PMID:22574260

High Strength and Ductility of Additively Manufactured 316L Stainless Steel Explained

NASA Astrophysics Data System (ADS)

Shamsujjoha, Md.; Agnew, Sean R.; Fitz-Gerald, James M.; Moore, William R.; Newman, Tabitha A.

2018-04-01

Structure-property relationships of an additively manufactured 316L stainless steel were explored. A scanning electron microscope and electron backscattered diffraction (EBSD) analysis revealed a fine cellular-dendritic (0.5 to 2 μm) substructure inside large irregularly shaped grains ( 100 μm). The cellular structure grows along the <100> crystallographic directions. However, texture analysis revealed that the main <100> texture component is inclined by 15 deg from the building direction. X-ray diffraction line profile analysis indicated a high dislocation density of 1 × 1015 m-2 in the as-built material, which correlates well with the observed EBSD microstructure and high-yield strength, via the traditional Taylor hardening equation. Significant variations in strain hardening behavior and ductility were observed for the horizontal (HB) and vertical (VB) built samples. Ductility of HB and VB samples measured 49 and 77 pct, respectively. The initial growth texture and subsequent texture evolution during tensile deformation are held responsible for the observed anisotropy. Notably, EBSD analysis of deformed samples showed deformation twins, which predominately form in the grains with <111> aligned parallel to the loading direction. The VB samples showed higher twinning activity, higher strain hardening rates at high strain, and therefore, higher ductility. Analysis of annealed samples revealed that the observed microstructures and properties are thermally stable, with only a moderate decrease in strength and very similar levels of ductility and anisotropy, compared with the as-built condition.

X-ray Diffraction Investigation of Annealing Behavior of Peened Surface Deformation Layer on Precipitation Hardening Stainless Steel

NASA Astrophysics Data System (ADS)

Huang, Junjie; Wang, Zhou; Gan, Jin; Yang, Ying; Huang, Feng; Wu, Gang; Meng, Qingshuai

2018-04-01

In order to investigate the recrystallization behavior of peened surface deformation layer of precipitation hardening stainless steel, a classic x-ray diffraction line profile analysis, Voigt method, was carried out on peened 17-4PH with different isothermal annealing temperatures. The activation energy of domain boundary migration (Q a) and the activation energy of microstrain relaxation (Q b) were calculated by regression analysis in different annealing temperature conditions. The results show that the value of Q a decreases with annealing temperature increasing, which is due to the influence of precipitation (ɛ-Cu) size on the movements of grain and subgrain boundaries. The maximum growth rate of ɛ-Cu particles occurs during 400 to 500 °C interval. Compared with growth behavior of domain size, microstrain relaxation behavior is less sensitive to precipitation particle size. The effects of annealing temperature and time on dislocation density are both significant when annealing temperature is lower than 500 °C. However, the effect of annealing temperature on dislocation density becomes insignificant when annealing temperature is higher than 500 °C. 300 °C annealing temperature only leads to the microstrain relaxation but nearly cannot lead to the domain size growth even if prolonging annealing time. Microstructure enhancement effect still exists in plastic deformation layer when 300 °C annealing temperature lasts for 60 min but nearly disappears when 600 °C annealing temperature lasts for 20 min.

High Strength and Ductility of Additively Manufactured 316L Stainless Steel Explained

NASA Astrophysics Data System (ADS)

Shamsujjoha, Md.; Agnew, Sean R.; Fitz-Gerald, James M.; Moore, William R.; Newman, Tabitha A.

2018-07-01

Structure-property relationships of an additively manufactured 316L stainless steel were explored. A scanning electron microscope and electron backscattered diffraction (EBSD) analysis revealed a fine cellular-dendritic (0.5 to 2 μm) substructure inside large irregularly shaped grains ( 100 μm). The cellular structure grows along the <100> crystallographic directions. However, texture analysis revealed that the main <100> texture component is inclined by 15 deg from the building direction. X-ray diffraction line profile analysis indicated a high dislocation density of 1 × 1015 m-2 in the as-built material, which correlates well with the observed EBSD microstructure and high-yield strength, via the traditional Taylor hardening equation. Significant variations in strain hardening behavior and ductility were observed for the horizontal (HB) and vertical (VB) built samples. Ductility of HB and VB samples measured 49 and 77 pct, respectively. The initial growth texture and subsequent texture evolution during tensile deformation are held responsible for the observed anisotropy. Notably, EBSD analysis of deformed samples showed deformation twins, which predominately form in the grains with <111> aligned parallel to the loading direction. The VB samples showed higher twinning activity, higher strain hardening rates at high strain, and therefore, higher ductility. Analysis of annealed samples revealed that the observed microstructures and properties are thermally stable, with only a moderate decrease in strength and very similar levels of ductility and anisotropy, compared with the as-built condition.

Line formation in the solar chromosphere. II - An optically thick region of the chromosphere-corona transition region observed with OSO 8

NASA Technical Reports Server (NTRS)

Lites, B. W.; Hansen, E. R.; Shine, R. A.

1980-01-01

The University of Colorado ultraviolet spectrometer aboard the Orbiting Solar Observatory 8(OSO 8) has measured self-reversed profiles of the resonance line of C IV lamda 1548.2 at the limb passage of an active region. The degree of the self-reversal together with the absolute intensity of the line profile determine the electron density in the active region at 10 to the 10th/cu cm at temperatures where the C IV line is formed. The nonthermal component of the broadening velocity is no more than 14km/s, and the physical thickness of an equivalent plane-parallel slab in hydrostatic equilibrium that would give rise to the observed line profiles is about 430 km.

Frequency-agile, rapid scanning cavity ring-down spectroscopy (FARS-CRDS) measurements of the (30012)←(00001) near-infrared carbon dioxide band

NASA Astrophysics Data System (ADS)

Long, D. A.; Wójtewicz, S.; Miller, C. E.; Hodges, J. T.

2015-08-01

We present new high accuracy measurements of the (30012)←(00001) CO2 band near 1575 nm recorded with a frequency-agile, rapid scanning cavity ring-down spectrometer. The resulting spectra were fit with the partially correlated, quadratic-speed-dependent Nelkin-Ghatak profile with line mixing. Significant differences were observed between the fitted line shape parameters and those found in existing databases, which are based upon more simplistic line profiles. Absolute transition frequencies, which were referenced to an optical frequency comb, are given, as well as the other line shape parameters needed to model this line profile. These high accuracy measurements should allow for improved atmospheric retrievals of greenhouse gas concentrations by current and future remote sensing missions.

Fast switchable ferroelectric liquid crystal gratings with two electro-optical modes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ma, Ying; Srivastava, A. K., E-mail: abhishek-srivastava-lu@yahoo.co.in; Chigrinov, V. G.

In this article, we reveal a theoretical and experimental illustration of the Ferroelectric liquid crystal (FLC) grating fabricated by mean of patterned alignment based on photo-alignment. The complexity related to the mismatching of the predefined alignment domains on the top and bottom substrate has been avoided by incorporating only one side photo aligned substrate while the other substrate does not have any alignment layer. Depending on the easy axis in the said alignment domains and the azimuth plane of the impinging polarized light, the diffracting element can be tuned in two modes i.e. DIFF/OFF switchable and DIFF/TRANS switchable modes, whichmore » can be applied to different applications. The diffraction profile has been illustrated theoretically that fits well with the experimental finding and thus the proposed diffraction elements with fast response time and high diffraction efficiency could find application in many modern devices.« less

Imperfection and radiation damage in protein crystals studied with coherent radiation

PubMed Central

Nave, Colin; Sutton, Geoff; Evans, Gwyndaf; Owen, Robin; Rau, Christoph; Robinson, Ian; Stuart, David Ian

2016-01-01

Fringes and speckles occur within diffraction spots when a crystal is illuminated with coherent radiation during X-ray diffraction. The additional information in these features provides insight into the imperfections in the crystal at the sub-micrometre scale. In addition, these features can provide more accurate intensity measurements (e.g. by model-based profile fitting), detwinning (by distinguishing the various components), phasing (by exploiting sampling of the molecular transform) and refinement (by distinguishing regions with different unit-cell parameters). In order to exploit these potential benefits, the features due to coherent diffraction have to be recorded and any change due to radiation damage properly modelled. Initial results from recording coherent diffraction at cryotemperatures from polyhedrin crystals of approximately 2 µm in size are described. These measurements allowed information about the type of crystal imperfections to be obtained at the sub-micrometre level, together with the changes due to radiation damage. PMID:26698068

LABORATORY MEASUREMENTS OF WHITE DWARF PHOTOSPHERIC SPECTRAL LINES: Hβ

DOE Office of Scientific and Technical Information (OSTI.GOV)

Falcon, Ross E.; Gomez, T. A.; Montgomery, M. H.

2015-06-20

We spectroscopically measure multiple hydrogen Balmer line profiles from laboratory plasmas to investigate the theoretical line profiles used in white dwarf (WD) atmosphere models. X-ray radiation produced at the Z Pulsed Power Facility at Sandia National Laboratories initiates plasma formation in a hydrogen-filled gas cell, replicating WD photospheric conditions. Here we present time-resolved measurements of Hβ and fit this line using different theoretical line profiles to diagnose electron density, n{sub e}, and n = 2 level population, n{sub 2}. Aided by synthetic tests, we characterize the validity of our diagnostic method for this experimental platform. During a single experiment, wemore » infer a continuous range of electron densities increasing from n{sub e} ∼ 4 to ∼30 × 10{sup 16} cm{sup −3} throughout a 120-ns evolution of our plasma. Also, we observe n{sub 2} to be initially elevated with respect to local thermodynamic equilibrium (LTE); it then equilibrates within ∼55 ns to become consistent with LTE. This supports our electron-temperature determination of T{sub e} ∼ 1.3 eV (∼15,000 K) after this time. At n{sub e} ≳ 10{sup 17} cm{sup −3}, we find that computer-simulation-based line-profile calculations provide better fits (lower reduced χ{sup 2}) than the line profiles currently used in the WD astronomy community. The inferred conditions, however, are in good quantitative agreement. This work establishes an experimental foundation for the future investigation of relative shapes and strengths between different hydrogen Balmer lines.« less

Imaging system design for improved information capacity

NASA Technical Reports Server (NTRS)

Fales, C. L.; Huck, F. O.; Samms, R. W.

1984-01-01

Shannon's theory of information for communication channels is used to assess the performance of line-scan and sensor-array imaging systems and to optimize the design trade-offs involving sensitivity, spatial response, and sampling intervals. Formulations and computational evaluations account for spatial responses typical of line-scan and sensor-array mechanisms, lens diffraction and transmittance shading, defocus blur, and square and hexagonal sampling lattices.

Elastic plastic self-consistent (EPSC) modeling of plastic deformation in fayalite olivine

DOE PAGES

Burnley, Pamela C

2015-07-01

Elastic plastic self-consistent (EPSC) simulations are used to model synchrotron X-ray diffraction observations from deformation experiments on fayalite olivine using the deformation DIA apparatus. Consistent with results from other in situ diffraction studies of monomineralic polycrystals, the results show substantial variations in stress levels among grain populations. Rather than averaging the lattice reflection stresses or choosing a single reflection to determine the macroscopic stress supported by the specimen, an EPSC simulation is used to forward model diffraction data and determine a macroscopic stress that is consistent with lattice strains of all measured diffraction lines. The EPSC simulation presented here includesmore » kink band formation among the plastic deformation mechanisms in the simulation. The inclusion of kink band formation is critical to the success of the models. This study demonstrates the importance of kink band formation as an accommodation mechanism during plastic deformation of olivine as well as the utility of using EPSC models to interpret diffraction from in situ deformation experiments.« less

Winds from T Tauri stars. II - Balmer line profiles for inner disk winds

NASA Technical Reports Server (NTRS)

Calvet, Nuria; Hartmann, Lee; Hewett, Robert

1992-01-01

Results are presented of calculations of Balmer emission line profiles using escape probability methods for T Tauri wind models with nonspherically symmetric geometry. The wind is assumed to originate in the inner regions of an accretion disk surrounding the T Tauri star, and flows outward in a 'cone' geometry. Two types of wind models are considered, both with monotonically increasing expansion velocities as a function of radial distance. For flows with large turbulent velocities, such as the HF Alfven wave-driven wind models, the effect of cone geometry is to increase the blue wing emission, and to move the absorption reversal close to line center. Line profiles for a wind model rotating with the same angular velocity as the inner disk are also calculated. The Balmer lines of this model are significantly broader than observed in most objects, suggesting that the observed emission lines do not arise in a region rotating at Keplerian velocity.

Mass loss from alpha Cyg /A2Ia/ derived from the profiles of low excitation Fe II lines

NASA Technical Reports Server (NTRS)

Hensberge, H.; De Loore, C.; Lamers, H. J. G. L. M.; Bruhweiler, F. C.

1982-01-01

The low-excitation Fe II lines in the spectral region 2000-3000 A are studied in the spectrum of alpha-Cyg. The profiles of the resonance lines are described by four representative parameters, and a preliminary model is derived from the dependence of these parameters on theoretical line strength, taking into account the influence of blending photospheric lines in an overall and qualitative way. At least 11% of all iron in the wind is once ionized, unless a non-thermal heating source enhances the fraction Fe(++) without destroying much Al(+). It is shown that the contribution of blending photospheric absorption lines to weaker P Cygni profiles has been previously largely underestimated. The mass loss rate corresponding to the model is derived, and is smaller by a factor of 500 than the one derived from the infrared excess by Barlow and Cohen (1977).

Gas kinematics in FIRE simulated galaxies compared to spatially unresolved H I observations

NASA Astrophysics Data System (ADS)

El-Badry, Kareem; Bradford, Jeremy; Quataert, Eliot; Geha, Marla; Boylan-Kolchin, Michael; Weisz, Daniel R.; Wetzel, Andrew; Hopkins, Philip F.; Chan, T. K.; Fitts, Alex; Kereš, Dušan; Faucher-Giguère, Claude-André

2018-06-01

The shape of a galaxy's spatially unresolved, globally integrated 21-cm emission line depends on its internal gas kinematics: galaxies with rotationally supported gas discs produce double-horned profiles with steep wings, while galaxies with dispersion-supported gas produce Gaussian-like profiles with sloped wings. Using mock observations of simulated galaxies from the FIRE project, we show that one can therefore constrain a galaxy's gas kinematics from its unresolved 21-cm line profile. In particular, we find that the kurtosis of the 21-cm line increases with decreasing V/σ and that this trend is robust across a wide range of masses, signal-to-noise ratios, and inclinations. We then quantify the shapes of 21-cm line profiles from a morphologically unbiased sample of ˜2000 low-redshift, H I-detected galaxies with Mstar = 107-11 M⊙ and compare to the simulated galaxies. At Mstar ≳ 1010 M⊙, both the observed and simulated galaxies produce double-horned profiles with low kurtosis and steep wings, consistent with rotationally supported discs. Both the observed and simulated line profiles become more Gaussian like (higher kurtosis and less-steep wings) at lower masses, indicating increased dispersion support. However, the simulated galaxies transition from rotational to dispersion support more strongly: at Mstar = 108-10 M⊙, most of the simulations produce more Gaussian-like profiles than typical observed galaxies with similar mass, indicating that gas in the low-mass simulated galaxies is, on average, overly dispersion supported. Most of the lower-mass-simulated galaxies also have somewhat lower gas fractions than the median of the observed population. The simulations nevertheless reproduce the observed line-width baryonic Tully-Fisher relation, which is insensitive to rotational versus dispersion support.

Velocity profiles of high-excitation molecular hydrogen lines

NASA Technical Reports Server (NTRS)

Moorhouse, A.; Brand, P. W. J. L.; Geballe, T. R.; Burton, M. G.

1990-01-01

Profiles of three lines of molecular hydrogen near 2.2 microns, originating from widely spaced energy levels, have been measured at a resolution of 32 km/s at Peak 1 in the Orion molecular outflow. The three lines, 1 - 0 S(1), 2 - 1 S(1), and 3 - 2 S(3), are found to have identical profiles. This result rules out any significant contribution to the population of the higher energy levels of molecular hydrogen at Peak 1 by fluorescence, and is generally consistent with emission from multiple J-type shocks.

The power of in situ pulsed laser deposition synchrotron characterization for the detection of domain formation during growth of Ba0.5Sr0.5TiO3 on MgO.

PubMed

Bauer, Sondes; Lazarev, Sergey; Molinari, Alan; Breitenstein, Andreas; Leufke, Philipp; Kruk, Robert; Hahn, Horst; Baumbach, Tilo

2014-03-01

A highly sophisticated pulsed laser deposition (PLD) chamber has recently been installed at the NANO beamline at the synchrotron facility ANKA (Karlsruhe, Germany), which allows for comprehensive studies on the PLD growth process of dielectric, ferroelectric and ferromagnetic thin films in epitaxial oxide heterostructures or even multilayer systems by combining in situ reflective high-energy diffraction with the in situ synchrotron high-resolution X-ray diffraction and surface diffraction methods. The modularity of the in situ PLD chamber offers the opportunity to explore the microstructure of the grown thin films as a function of the substrate temperature, gas pressure, laser fluence and target-substrate separation distance. Ba0.5Sr0.5TiO3 grown on MgO represents the first system that is grown in this in situ PLD chamber and studied by in situ X-ray reflectivity, in situ two-dimensional reciprocal space mapping of symmetric X-ray diffraction and acquisition of time-resolved diffraction profiles during the ablation process. In situ PLD synchrotron investigation has revealed the occurrence of structural distortion as well as domain formation and misfit dislocation which all depend strongly on the film thickness. The microstructure transformation has been accurately detected with a time resolution of 1 s. The acquisition of two-dimensional reciprocal space maps during the PLD growth has the advantage of simultaneously monitoring the changes of the crystalline structure as well as the formation of defects. The stability of the morphology during the PLD growth is demonstrated to be remarkably affected by the film thickness. A critical thickness for the domain formation in Ba0.5Sr0.5TiO3 grown on MgO could be determined from the acquisition of time-resolved diffraction profiles during the PLD growth. A splitting of the diffraction peak into two distinguishable peaks has revealed a morphology change due to modification of the internal strain during growth.

Seasonal Variations in the CO Line Profile and the Retrieved Thermal/Pressure Structures in the Atmosphere of Mars

NASA Astrophysics Data System (ADS)

Khayat, Alain; Villanueva, G. L.; Mumma, M. J.; Riesen, T. E.; Tokunaga, A. T.

2013-10-01

We report retrievals of temperature vertical profiles up to 100 km over Tharsis and Syrtis regions on Mars obtained by inverting the strong rotational (3-2) line of carbon monoxide (CO) at 346 GHz. Observations of CO were made from mid Northern Spring to early Northern Summer on Mars (Ls= 36°-108°, 23 Nov, 2011 - 13 May, 2012) using the Caltech Submillimeter Observatory's (CSO) high-resolution heterodyne receiver (Barney) on top of Mauna Kea, Hawai'i. The temperature profiles were derived using our radiative transfer model that considers the latest spectroscopic constants for CO collisionally broadened by CO2. We observe notable changes of the line profile for different dates, which are directly related to seasonal variations in the thermal/pressure structure of the atmosphere. The seasonal variability of the martian CO line profile, the extracted temperature profiles, and comparisons with modeled profiles from the Mars Climate Database (Lewis et al, 1999) will be presented. We gratefully acknowledge support from the NASA Planetary Astronomy Program , NASA Astrobiology Institute, Planetary Atmospheres programs. This material is based upon work at the Caltech Submillimeter Observatory, which is operated by the California Institute of Technology under cooperative agreement with the National Science Foundation, grant number AST-0838261.

Interference from the Robledo DSN Transmitters to Central Madrid IMT-2000/UMTS System through Terrain Diffraction at S-Band

NASA Technical Reports Server (NTRS)

Ho, Christian M.; Sue, Miles K.; Peng, Ted K.; Smith, Ernest K.

2002-01-01

This study evaluates the possible interference from DSN Robledo 70-m transmitter with Madrid IMT-2000/UMTS wireless users in Spain as both systems will share the same frequency band. Using the effective earth radius, the 50 km terrain profile between Robledo and Madrid is modified and reconstructed. The diffraction propagation losses due to mountain peaks are calculated for the receivers in Madrid urban area. The mountains along the path are simplified into a rounded knife-edge and a rounded obstacle. The results show that for a near surface receiver (1.5 m above the ground) in Madrid, interference signal powers received are less than -135 dBm, which is far below the -109 dBm, the IMT-2000 wireless phone threshold. When a receiver is located at about 40 m above the ground (e.g., the top of Clock Tower of Cibeles Palace), diffraction will generate interference power less than -115 dBm. We find that our calculation results are basically consistent with those from the Longley-Rice model, while the latter has smaller loss because of the low resolution terrain profile used. As a comparison, we also find that the measurements of interference powers of -121.2 dBm at the top of Clock tower is in the range of the estimation. We conclude that the interference through the diffraction mechanism will not cause any problem to IMT-2000/UMTS users at near the surface of Madrid urban area.

Computation of nonstationary strong shock diffraction by curved surfaces

NASA Technical Reports Server (NTRS)

Yang, J. Y.; Lombard, C. K.; Bershader, D.

1986-01-01

A two-dimensional, high resolution shock-capturing algorithm was used on a supercomputer to solve Eulerian gasdynamic equations in order to simulate nonstationary strong shock diffraction by a circular arc model in a shock tube. The hypersonic Mach shock wave was assumed to arrive at a high angle of incidence, and attention was given to the effect of varying values of the ratio of specific heats on the shock diffraction process. Details of the conservation equations of the numerical algorithm, written in curvilinear coordinates, are provided, and model output is illustrated with the results generated for a Mach shock encountering a 15 deg circular arc. The sample graphics include isopycnics, a shock surface density profile, and pressure and Mach number contours.

Rayleigh-wave diffractions due to a void in the layered half space

USGS Publications Warehouse

Xia, J.; Xu, Y.; Miller, R.D.; Nyquist, Jonathan E.

2006-01-01

Void detection is challenging due to the complexity of near-surface materials and the limited resolution of geophysical methods. Although multichannel, high-frequency, surface-wave techniques can provide reliable shear (S)-wave velocities in different geological settings, they are not suitable for detecting voids directly based on anomalies of the S-wave velocity because of limitations on the resolution of S-wave velocity profiles inverted from surface-wave phase velocities. Xia et al. (2006a) derived a Rayleigh-wave diffraction traveltime equation due to a void in the homogeneous half space. Encouraging results of directly detecting a void from Rayleigh-wave diffractions were presented (Xia et al., 2006a). In this paper we used four two-dimensional square voids in the layered half space to demonstrate the feasibility of detecting a void with Rayleigh-wave diffractions. Rayleigh-wave diffractions were recognizable for all these models after removing direct surface waves by F-K filtering. We evaluate the feasibility of applying the Rayleigh-wave diffraction traveltime equation to a void in the layered earth model. The phase velocity of diffracted Rayleigh waves is predominately determined by surrounding materials of a void. The modeling results demonstrate that the Rayleigh-wave diffraction traveltime equation due to a void in the homogeneous half space can be applied to the case of a void in the layered half space. In practice, only two diffraction times are necessary to define the depth to the top of a void and the average velocity of diffracted Rayleigh waves. ?? 2005 Society of Exploration Geophysicists.

Evaluation of the LIA-ANA-Profile-17S for the detection of autoantibodies to nuclear antigens.

PubMed

Yi, Ahram; Lee, Chang-Hoon; Moon, Hee-Won; Kim, Hanah; Hur, Mina; Yun, Yeo-Min

2018-05-01

The diagnostic tests for autoimmune disease include screening for autoantibodies for nuclear antigens (ANA) and antibodies against extractable nuclear antigens (ENA). Using the line immunoassay (LIA) method, various kinds of ENA antibodies can be detected simultaneously. We evaluated the performance of the newly launched LIA-ANA-Profile-17S (Shenzhen YHLO Biotech, Shenzhen, China) as compared to a conventional LIA kit. Residual samples were collected from 200 patients who had been tested for ANA using indirect immunofluorescence. The LIA-ANA-Profile-17S was compared to the EuroLine ANA (Euroimmun, Oberlausitz, Germany) for the analysis of 17 different autoantibodies. The concordance rate and agreement between assays were determined. Samples showing discrepancies between the LIA-ANA-Profile-17S and EuroLine tests were further examined through additional analysis. The overall agreement was moderate (kappa = 0.759, 95% CI = 0.712-0.805). Agreement between assays ranged from weak to almost perfect, except for those tests targeting nucleosomes, histones, and PM-Scl. Of the 57 disparate results between LIA-ANA-Profile-17S and EuroLine, 38 (66.7%) samples tested positive under an additional assay, showing variable patterns between types of autoantibodies. The positive rate of each autoantibody between LIA-ANA-Profile-17S and EuroLine did not differ significantly, except for anti-nucleosome and anti-histone assays in samples from patients diagnosed with systemic lupus erythematosus (P = 0.004 and 0.001, respectively). Compared to those from the conventional EuroLine assay, the LIA-ANA-Profile-17S results showed variable agreement in samples showing different prevalence of each autoantibody. The most frequently detected antibodies showed almost perfect agreement. The LIA-ANA-Profile-17S could play a role in the diagnosis of systemic autoimmune disease in ANA-positive samples. Copyright © 2018 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

Electromigration-induced plastic deformation in passivated metal lines

NASA Astrophysics Data System (ADS)

Valek, B. C.; Bravman, J. C.; Tamura, N.; MacDowell, A. A.; Celestre, R. S.; Padmore, H. A.; Spolenak, R.; Brown, W. L.; Batterman, B. W.; Patel, J. R.

2002-11-01

We have used scanning white beam x-ray microdiffraction to study microstructural evolution during an in situ electromigration experiment on a passivated Al(Cu) test line. The data show plastic deformation and grain rotations occurring under the influence of electromigration, seen as broadening, movement, and splitting of reflections diffracted from individual metal grains. We believe this deformation is due to localized shear stresses that arise due to the inhomogeneous transfer of metal along the line. Deviatoric stress measurements show changes in the components of stress within the line, including relaxation of stress when current is removed.

Pulsational mode-typing in line profile variables. I - Four Beta Cephei stars

NASA Technical Reports Server (NTRS)

Campos, A. J.; Smith, M. A.

1980-01-01

The detailed variations of line profiles in the Beta Cephei-type variable stars Gamma Pegasi, Beta Cephei, Delta Ceti and Sigma Scorpii are modeled throughout their pulsation cycles in order to classify the dominant pulsation mode as radial or nonradial. High-dispersion Reticon observations of the variables were obtained for the Si III line at 4567 A, and line profiles broadened by radial or nonradial pulsations, rotation and radial-tangential macroturbulence were calculated based on a model atmosphere. It is found that only a radial pulsation mode can reproduce the radial velocity amplitude, changes in line asymmetry and uniform line width observed in all four stars. Results are in agreement with the color-to-light arguments of Stamford and Watson (1978), and suggest that radial pulsation plays the dominant role in the observed variations in most Beta Cephei stars. Evidence for shocks or moving shells is also found in visual line data for Sigma Scorpii and an ultraviolet line of Beta Cephei, together with evidence of smooth, secular period changes in Beta Cephei and Delta Ceti.

On the synthesis of resonance lines in dynamical models of structured hot-star winds

NASA Technical Reports Server (NTRS)

Puls, J.; Owocki, S. P.; Fullerton, A. W.

1993-01-01

We examine basic issues involved in synthesizing resonance-line profiles from 1-D, dynamical models of highly structured hot-star winds. Although these models exhibit extensive variations in density as well as velocity, the density scale length is still typically much greater than the Sobolev length. The line transfer is thus treated using a Sobolev approach, as generalized by Rybicki & Hummer (1978) to take proper account of the multiple Sobolev resonances arising from the nonmonotonic velocity field. The resulting reduced-lambda-matrix equation describing nonlocal coupling of the source function is solved by iteration, and line profiles are then derived from formal solution integration using this source function. Two more approximate methods that instead use either a stationary or a structured, local source function yield qualitatively similar line-profiles, but are found to violate photon conservation by 10% or more. The full results suggest that such models may indeed be able to reproduce naturally some of the qualitative properties long noted in observed UV line profiles, such as discrete absorption components in unsaturated lines, or the blue-edge variability in saturated lines. However, these particular models do not yet produce the black absorption troughs commonly observed in saturated lines, and it seems that this and other important discrepancies (e.g., in acceleration time scale of absorption components) may require development of more complete models that include rotation and other 2-D and/or 3-D effects.

Fluctuations at the blue edge of saturated wind lines in IUE spectra of O-type stars

NASA Technical Reports Server (NTRS)

Owocki, Stanley P.; Fullerton, Alex

1993-01-01

We examine basic issues involved in synthesizing resonance-line profiles from 1-D, dynamical models of highly structured hot-star winds. Although these models exhibit extensive variations in density as well as velocity, the density scale length is still typically much greater than the Sobolev length. The line transfer is thus treated using a Sobolev approach, as generalized by Rybicki & Hummer (1978) to take proper account of the multiple Sobolev resonances arising from the nonmonotonic velocity field. The resulting reduced-Lambda-matrix equation describing nonlocal coupling of the source function is solved by iteration, and line profiles and then derived from formal solution integration using this source function. The more appropriate methods that instead use either a stationary or a structured, local source function yield qualitatively similar line-profiles, but are found to violate photon conservation by 10 percent or more. The full results suggest that such models may indeed be able to reproduce naturally some of the qualitative properties long noted in observed UV line profiles, such as discrete absorption components in unsaturated lines, or the blue-edge variability in saturated lines. However, these particular models do not yet produce the black absorption troughs commonly observed in saturated lines, and it seems that this and other important discrepancies (e.g., in acceleration time scale of absorption components) may require development of more complete models that include rotation and other 2-D and/or 3-D effects.

Precision Control of the Electron Longitudinal Bunch Shape Using an Emittance-Exchange Beam Line

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ha, Gwanghui; Cho, Moo -Hyun; Namkung, W.

2017-03-09

Here, we report on the experimental generation of relativistic electron bunches with a tunable longitudinal bunch shape. A longitudinal bunch-shaping (LBS) beam line, consisting of a transverse mask followed by a transverse-to-longitudinal emittance exchange (EEX) beam line, is used to tailor the longitudinal bunch shape (or current profile) of the electron bunch. The mask shapes the bunch’s horizontal profile, and the EEX beam line converts it to a corresponding longitudinal profile. The Argonne wakefield accelerator rf photoinjector delivers electron bunches into a LBS beam line to generate a variety of longitudinal bunch shapes. The quality of the longitudinal bunch shapemore » is limited by various perturbations in the exchange process. We develop a simple method, based on the incident slope of the bunch, to significantly suppress the perturbations.« less

A spectroscopic search for colliding stellar winds in O-type close binary systems. IV - Iota Orionis

NASA Technical Reports Server (NTRS)

Gies, Douglas R.; Wiggs, Michael S.; Bagnuolo, William G., Jr.

1993-01-01

We present H-alpha and He I 6678 A line profiles for the eccentric orbit binary Iota Ori. We have applied a tomography algorithm which uses the established orbital velocity curves and intensity ratio to reconstruct the spectral line profiles for each star. The He I profiles appear as pure photospheric lines, and H-alpha shows variable emission in the line core throughout the orbit (which is typical of O giants) and in the blue wing near periastron passage. We show that the blue wing emission is consistent with an origin between the stars which probably results from a dramatic focusing of the primary's stellar wind at periastron. We also present IUE archival spectra of the UV wind lines N V 1240 A and C IV 1550 A.

Demonstration of Current Profile Shaping using Double Dog-Leg Emittance Exchange Beam Line at Argonne Wakefield Accelerator

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ha, Gwanghui; Cho, Moo-Hyun; Conde, Manoel

Emittance exchange (EEX) based longitudinal current profile shaping is the one of the promising current profile shaping technique. This method can generate high quality arbitrary current profiles under the ideal conditions. The double dog-leg EEX beam line was recently installed at the Argonne Wakefield Accelerator (AWA) to explore the shaping capability and confirm the quality of this method. To demonstrate the arbitrary current profile generation, several different transverse masks are applied to generate different final current profiles. The phase space slopes and the charge of incoming beam are varied to observe and suppress the aberrations on the ideal profile. Wemore » present current profile shaping results, aberrations on the shaped profile, and its suppression.« less

X-Ray Crystallographic Studies on Acetylcholinesterase and on Its Interaction with Anticholinesterase Agents.

DTIC Science & Technology

1994-11-24

complexes with reversible ligands, including edrophonium, d-tubocurarine and huperzine A , diffracting to similar resolution. The X26c Laue beam line...The EMBL-DESY synchrotron facility at Hamburg was employed to collect a complete 2.3 A data set for a crystal of native Torpedo AChE, as well as for...at the NSLS synchrotron facility at Brookhaven National Laboratory (BNL) was used to obtain a Laue diffraction pattern for a crystal of native Torpedo

The Influence of Growth Temperature on Sb Incorporation in InAsSb, and the Temperature-dependent Impact of Bi Surfactants

DTIC Science & Technology

2014-01-01

resolution X - ray diffraction (XRD) were collected for all samples, and reciprocal space maps (RSMs) were collected from selected samples. The complete data...exposure. The lines represent the model fit. 19 13 Figure 1. Triple axis x - ray diffraction from the bi-layered InAsSb structures grown on GaSb at...Applied Physics, Structural properties of bismuth‐bearing semiconductor alloys, 63 (1988) 107. 18 12 Figure Captions Figure 1. Triple axis x - ray

Notes on the availability of mid-Atlantic multichannel seismic reflection profiles 11 and 12-A, -B, -C, and -D

USGS Publications Warehouse

Schlee, John Stevens

1978-01-01

Available are two multichannel profiles collected by Digicon Geophysical Corporation in 1975 using a 48-channel streamer (3600 m long). and a 27.9 cu. liter air gun array. They were processed in Denver on the Phoenix "I" by William C. Patterson. The processing included demultiplexing and resampling, geometry and common-depth-point definition, velocity analysis, noise muting, band-pass filtering, time-variant filtering, time-variant deconvolution, and automatic gain control (AGC) scaling, prior to the final profile playout.The release includes parts of two lines off the mid-atlantic continental margin (see map) over the Baltimore Canyon trough. These profiles were collected as part of a regional grid over the offshore Atlantic sedimentary basins, as a part of a continuing program to assess the resource potential using non-proprietary data Line 11 is a cross shelf profile (233 ken long) taken across the shelf, slope and upper rise off Virginia (southern Baltimore Canyon trough). Line 12 (shotpoint 1Ol- 6011, parts A, 8, C and D) is an along-the-shelf profiler and stretches from the Cape Hatteras IPOD line to line 2, at the northern part of the Baltimore Canyon trough), a distance of 591 km.These profiles may be viewed at the U.S. Geological Survey, Atlantic Gulf of Mexico, Office of Marine Geology, Quissett campus, Building B, Woods Hole, Massachusetts 02543, and at the U.S. Geological Survey, Branch of Oil and Gas Resources, Denver Federal Center, Building 25, Denver. Colorado 80225. Copies of the profiles can be purchased from the Nations Geophysical and Solar-Terrestrial Data Center, Environmental Data Service- NOAA, Code D621 Boulder, Colorado 80303.

Calculation of x-ray scattering patterns from nanocrystals at high x-ray intensity

PubMed Central

Abdullah, Malik Muhammad; Jurek, Zoltan; Son, Sang-Kil; Santra, Robin

2016-01-01

We present a generalized method to describe the x-ray scattering intensity of the Bragg spots in a diffraction pattern from nanocrystals exposed to intense x-ray pulses. Our method involves the subdivision of a crystal into smaller units. In order to calculate the dynamics within every unit, we employ a Monte-Carlo-molecular dynamics-ab-initio hybrid framework using real space periodic boundary conditions. By combining all the units, we simulate the diffraction pattern of a crystal larger than the transverse x-ray beam profile, a situation commonly encountered in femtosecond nanocrystallography experiments with focused x-ray free-electron laser radiation. Radiation damage is not spatially uniform and depends on the fluence associated with each specific region inside the crystal. To investigate the effects of uniform and non-uniform fluence distribution, we have used two different spatial beam profiles, Gaussian and flattop. PMID:27478859

Wavefront modulation and subwavelength diffractive acoustics with an acoustic metasurface.

PubMed

Xie, Yangbo; Wang, Wenqi; Chen, Huanyang; Konneker, Adam; Popa, Bogdan-Ioan; Cummer, Steven A

2014-11-24

Metasurfaces are a family of novel wavefront-shaping devices with planar profile and subwavelength thickness. Acoustic metasurfaces with ultralow profile yet extraordinary wave manipulating properties would be highly desirable for improving the performance of many acoustic wave-based applications. However, designing acoustic metasurfaces with similar functionality to their electromagnetic counterparts remains challenging with traditional metamaterial design approaches. Here we present a design and realization of an acoustic metasurface based on tapered labyrinthine metamaterials. The demonstrated metasurface can not only steer an acoustic beam as expected from the generalized Snell's law, but also exhibits various unique properties such as conversion from propagating wave to surface mode, extraordinary beam-steering and apparent negative refraction through higher-order diffraction. Such designer acoustic metasurfaces provide a new design methodology for acoustic signal modulation devices and may be useful for applications such as acoustic imaging, beam steering, ultrasound lens design and acoustic surface wave-based applications.

High efficiency x-ray nanofocusing by the blazed stacking of binary zone plates

NASA Astrophysics Data System (ADS)

Mohacsi, I.; Karvinen, P.; Vartiainen, I.; Diaz, A.; Somogyi, A.; Kewish, C. M.; Mercere, P.; David, C.

2013-09-01

The focusing efficiency of binary Fresnel zone plate lenses is fundamentally limited and higher efficiency requires a multi step lens profile. To overcome the manufacturing problems of high resolution and high efficiency multistep zone plates, we investigate the concept of stacking two different binary zone plates in each other's optical near-field. We use a coarse zone plate with π phase shift and a double density fine zone plate with π/2 phase shift to produce an effective 4- step profile. Using a compact experimental setup with piezo actuators for alignment, we demonstrated 47.1% focusing efficiency at 6.5 keV using a pair of 500 μm diameter and 200 nm smallest zone width. Furthermore, we present a spatially resolved characterization method using multiple diffraction orders to identify manufacturing errors, alignment errors and pattern distortions and their effect on diffraction efficiency.

X-ray investigations related to the shock history of the Shergotty achondrite

NASA Technical Reports Server (NTRS)

Horz, F.; Hanss, R.; Serna, C.

1986-01-01

The shock stress suffered by naturally shocked materials from the Shergotty achondrite was studied using X-ray diffraction techniques and experimentally shocked augite and enstatite as standards. The Shergotty pyroxenes revealed the formation of continuous diffraction rings, line broadening, preferred orientation of small scale diffraction domains, and other evidence of substantial lattice disorders. As disclosed by the application of Debye-Scherrer techniques, they are hybrids between single crystals and fine-grained random powders. The pyroxene lattice is very resistant to shock damage on smaller scales. While measurable lattice disaggregation and progressive fragmentation occur below 25 GPa, little additional damage is suffered from application of pressures between 30 to 60 GPa, making pressure calibration of naturally shocked pyroxenes via X-ray methods difficult. Powder diffractometer scans on pure maskelynite fractions of Shergotty revealed small amounts of still coherently diffracting plagioclase, which may contribute to the high refractive indices of the diaplectic feldspar glasses of Shergotty.

Alternate Multilayer Gratings with Enhanced Diffraction Efficiency in the 500-5000 eV Energy Domain

NASA Astrophysics Data System (ADS)

Polack, François; Lagarde, Bruno; Idir, Mourad; Cloup, Audrey Liard; Jourdain, Erick; Roulliay, Marc; Delmotte, Franck; Gautier, Julien; Ravet-Krill, Marie-Françoise

2007-01-01

An alternate multilayer (AML) grating is a 2 dimensional diffraction structure formed on an optical surface, having a 0.5 duty cycle in the in-plane and in the in-depth direction. It can be made by covering a shallow depth laminar grating with a multilayer stack. We show here that their 2D structure confer AML gratings a high angular and energetic selectivity and therefore enhanced diffraction properties, when used in grazing incidence. In the tender X-ray range (500eV - 5000 eV) they behave much like blazed gratings. Over 15% efficiency has been measured on a 1200 lines/mm Mo/Si AML grating in the 1.2 - 1.5 keV energy range. Computer simulations show that selected multilayer materials such as Cr/C should allow diffraction efficiency over 50% at photon energies over 3 keV.

Rotary encoding device using polygonal mirror with diffraction gratings on each facet

NASA Technical Reports Server (NTRS)

Leviton, Douglas B. (Inventor)

1993-01-01

A device for position encoding of a rotating shaft in which a polygonal mirror having a number of facets is mounted to the shaft and a monochromatic light beam is directed towards the facets. The facets of the polygonal mirror each have a low line density diffraction grating to diffract the monochromatic light beam into a number of diffracted light beams such that a number of light spots are created on a linear array detector. An analog-to-digital converter is connected to the linear array detector for reading the position of the spots on the linear array detector means. A microprocessor with memory is connected to the analog-to-digital converter to hold and manipulate the data provided by the analog-to-digital converter on the position of the spots and to compute the position of the shaft based upon the data from the analog-to-digital converter.

Valence fluctuating compound α-YbAlB4 studied by 174Yb Mössbauer spectroscopy and X-ray diffraction using synchrotron radiation

NASA Astrophysics Data System (ADS)

Oura, Momoko; Ikeda, Shugo; Masuda, Ryo; Kobayashi, Yasuhiro; Seto, Makoto; Yoda, Yoshitaka; Hirao, Naohisa; Kawaguchi, Saori I.; Ohishi, Yasuo; Suzuki, Shintaro; Kuga, Kentaro; Nakatsuji, Satoru; Kobayashi, Hisao

2018-05-01

The structural properties and the Yb 4 f electronic state of the valence fluctuating α-YbAlB4 have been investigated by powder X-ray diffraction under pressure and 174Yb Mössbauer spectroscopy with magnetic fields at low temperature, respectively, using synchrotron radiation. Powder X-ray diffraction patterns showed that the crystal structure does not change up to p ∼ 18 GPa at 8 K and the volume decreases smoothly. However, the pressure dependence of the difference in the structure factor between the (060) and (061) diffraction lines changes at ∼ 3.4 GPa, indicating the change of atomic coordination parameters. The 174Yb Mössbauer spectroscopy measurements at 2 K with 10 and 50 kOe suggest that the electrical quadrupole interaction changes by applied magnetic fields.

High resolution neutron Larmor diffraction using superconducting magnetic Wollaston prisms

DOE PAGES

Li, Fankang; Feng, Hao; Thaler, Alexander N.; ...

2017-04-13

The neutron Larmor diffraction technique has been implemented using superconducting magnetic Wollaston prisms in both single-arm and double-arm configurations. Successful measurements of the coefficient of thermal expansion of a single-crystal copper sample demonstrates that the method works as expected. Our experiment involves a new method of tuning by varying the magnetic field configurations in the device and the tuning results agree well with previous measurements. The difference between single-arm and double-arm configurations has been investigated experimentally. Here, we conclude that this measurement benchmarks the applications of magnetic Wollaston prisms in Larmor diffraction and shows in principle that the setup canmore » be used for inelastic phonon line-width measurements. The achievable resolution for Larmor diffraction is comparable to that using Neutron Resonance Spin Echo (NRSE) coils. Furthermore, the use of superconducting materials in the prisms allows high neutron polarization and transmission efficiency to be achieved.« less

H α and H β Raman scattering line profiles of the symbiotic star AG Pegasi

NASA Astrophysics Data System (ADS)

Lee, Seong-Jae; Hyung, Siek

2018-04-01

The H α and H β line profiles of the symbiotic star AG Pegasi, observed in 1998 September (phase ϕ = 10.24), display top narrow double Gaussian components and bottom broad components (FWHM = 200-400 km s-1). The photoionization model indicates that the ionized zone, responsible for the hydrogen Balmer and Lyman lines, is radiation-bounded, with a hydrogen gas number density of nH ˜ 109.85 cm-3 and a gas temperature of Te = 12 000-15 000 K. We have carried out Monte Carlo simulations to fit the Raman scattering broad wings, assuming that the hydrogen Ly β and Ly γ lines emitted within the radiation-bounded H II zone around a white dwarf have the same double Gaussian line profile shape as the hydrogen Balmer lines. The simulation shows that the scattering H I zones are attached to (or located just outside) the inner H II shells. The best fit to the observed broad H I line profiles indicates that the column density of the scattering neutral zone is NH ≃ 3-5 × 1019 cm-2. We have examined whether the geometrical structure responsible for the observed H α and H β line profiles is a bipolar conical shell structure, consisting of the radiation-bounded ionized zone and the outer material bounded neutral zone. The expanding bipolar structure might be two opposite regions of the common envelope or the outer shell of the Roche lobe around the hot white dwarf, formed through the mass inflows from the giant star and pushed out by the fast winds from the hot white dwarf.

The STIS CCD Spectroscopic Line Spread Functions

NASA Technical Reports Server (NTRS)

Gull, T.; Lindler, D.; Tennant, D.; Bowers, C.; Grady, C.; Hill, R. S.; Malumuth, E.

2002-01-01

We characterize the spectroscopic line spread functions of the spectroscopic CCD modes for high contrast objects. Our long range goal is to develop tools that accurately extract spectroscopic information of faint, point or extended sources in the vicinity of bright, point sources at separations approaching the realizable angular limits of HST with STIS. Diffracted and scattered light due to the HST optics, and scattered light effects within the STIS are addressed. Filter fringing, CCD fringing, window reflections, and scattering within the detector and other effects are noted. We have obtained spectra of several reference stars, used for flux calibration or for coronagraphic standards, that have spectral distributions ranging from very red to very blue. Spectra of each star were recorded with the star in the aperture and with the star blocked by either the F1 or F2 fiducial. Plots of the detected starlight along the spatial axis of the aperture are provided for four stars. With the star in the aperture, the line spread function is quite noticeable. Placing the star behind one of the fiducials cuts the scattered light and the diffracted light, is detectable even out to 1OOOOA. When the star is placed behind either fiducial, the scattered and diffracted light components, at three arcseconds displacement from the star, are below lop6 the peak of the star at wavelengths below 6000A; at the same angular distance, scattered light does contaminate the background longward of 6000A up to a level of 10(exp -5).

SPECTRO-POLARIMETRIC SIMULATIONS OF THE SOLAR LIMB: ABSORPTION-EMISSION Fe I 6301.5 Å AND 6302.5 Å LINE PROFILES AND TORSIONAL FLOWS IN THE INTERGRANULAR MAGNETIC FLUX CONCENTRATIONS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shelyag, S.

2015-03-01

Using radiative magnetohydrodynamic simulations of the magnetized solar photosphere and detailed spectro-polarimetric diagnostics with the Fe I 6301.5 Å and 6302.5 Å photospheric lines in the local thermodynamic equilibrium approximation, we model active solar granulation as if it was observed at the solar limb. We analyze general properties of the radiation across the solar limb, such as the continuum and the line core limb darkening and the granulation contrast. We demonstrate the presence of profiles with both emission and absorption features at the simulated solar limb, and pure emission profiles above the limb. These profiles are associated with the regionsmore » of strong linear polarization of the emergent radiation, indicating the influence of the intergranular magnetic fields on the line formation. We analyze physical origins of the emission wings in the Stokes profiles at the limb, and demonstrate that these features are produced by localized heating and torsional motions in the intergranular magnetic flux concentrations.« less

A space bourne crystal diffraction telescope for the energy range of nuclear transitions

DOE Office of Scientific and Technical Information (OSTI.GOV)

von Ballmoos, P.; Naya, J.E.; Albernhe, F.

1995-10-01

Recent experimental work of the Toulouse-Argonne collaboration has opened for perspective of a focusing gamma-ray telescope operating in the energy range of nuclear transitions, featuring unprecedented sensitivity, angular and energy resolution. The instrument consists of a tunable crystal diffraction lens situated on a stabilized spacecraft, focusing gamma-rays onto a small array of Germanium detectors perched on an extendible boom. While the weight of such an instrument is less than 500 kg, it features an angular resolution of 15 in., an energy resolution of 2 keV and a 3 {sigma} narrow line sensitivity of a few times 10{sup {minus}7} photons s{supmore » {minus}1} cm{sup {minus}2} (10{sup 6} sec observation). This instrumental concept permits observation of any identified source at any selected line-energy in a range of typically 200 keV to 1300 keV. The resulting ``sequential`` operation mode makes sites of explosive nucleosynthesis natural scientific objectives for such a telescope: the nuclear lines of extragalactic supernovae ({sup 56}Ni, {sup 44}Ti, {sup 60}Fe) and galactic novae (p{sup {minus}}p{sup +} line, {sup 7}Be) are accessible to observation, one at a time, due to the erratic appearance and the sequence of half-lifes of these events. Other scientific objectives, include the narrow 511 keV line from galactic broad class annihilators (such as 1E1740-29, nova musca) and possible redshifted annihilation lines from AGN`s.« less

Laser plasma x-ray line spectra fitted using the Pearson VII function

NASA Astrophysics Data System (ADS)

Michette, A. G.; Pfauntsch, S. J.

2000-05-01

The Pearson VII function, which is more general than the Gaussian, Lorentzian and other profiles, is used to fit the x-ray spectral lines produced in a laser-generated plasma, instead of the more usual, but computationally expensive, Voigt function. The mean full-width half-maximum of the fitted lines is 0.102+/-0.014 nm, entirely consistent with the value expected from geometrical considerations, and the fitted line profiles are generally inconsistent with being either Lorentzian or Gaussian.

Use of scatterometry for resist process control

NASA Astrophysics Data System (ADS)

Bishop, Kenneth P.; Milner, Lisa-Michelle; Naqvi, S. Sohail H.; McNeil, John R.; Draper, B. L.

1992-06-01

The formation of resist lines having submicron critical dimensions (CDs) is a complex multistep process, requiring precise control of each processing step. Optimization of parameters for each processing step may be accomplished through theoretical modeling techniques and/or the use of send-ahead wafers followed by scanning electron microscope measurements. Once the optimum parameters for any process having been selected, (e.g., time duration and temperature for post-exposure bake process), no in-situ CD measurements are made. In this paper we describe the use of scatterometry to provide this essential metrology capability. It involves focusing a laser beam on a periodic grating and predicting the shape of the grating lines from a measurement of the scattered power in the diffraction orders. The inverse prediction of lineshape from a measurement of the scatter power is based on a vector diffraction analysis used in conjunction with photolithography simulation tools to provide an accurate scatter model for latent image gratings. This diffraction technique has previously been applied to looking at latent image grating formation, as exposure is taking place. We have broadened the scope of the application and consider the problem of determination of optimal focus.

A platform for detecting material melting from shock compression using the NIF x-ray diffraction diagnostic TARDIS

NASA Astrophysics Data System (ADS)

Wehrenberg, Christopher; Kraus, Richard; Braun, Dave; Rygg, Ryan; Coppari, Federica; Lazicki, Amy; McNaney, James; Eggert, Jon

2016-10-01

A series of experiments were performed on NIF to develop a platform to detect material melting during shock compression using x-ray diffraction. The unique pulse shaping on NIF can be utilized to directly-drive a steady shock into an ablator and material sample while simultaneously creating an x-ray source to probe the material state. Sharp diffraction lines are observed when the material is in the solid state, while broad diffuse lines are seen when in the liquid state, providing an unambiguous signal for shock driven melting. Several shots were performed in which a shock of 50-80 GPa was driven into a Pb sample while a Ge foil was used as an x-ray source probe. Laser conditions were varied to create a suitable x-ray source that provides a short, bright burst of He-alpha emission from the Ge while maintaining a low background level on the image plates contained in the TARDIS diagnostic. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344.

Release behavior and toxicity profiles towards A549 cell lines of ciprofloxacin from its layered zinc hydroxide intercalation compound

PubMed Central

2013-01-01

Background Layered hydroxides salts (LHS), a layered inorganic compound is gaining attention in a wide range of applications, particularly due to its unique anion exchange properties. In this work, layered zinc hydroxide nitrate (LZH), a family member of LHS was intercalated with anionic ciprofloxacin (CFX), a broad spectrum antibiotic via ion exchange in a mixture solution of water:ethanol. Results Powder x-ray diffraction (XRD), Fourier transform infrared (FTIR) and thermogravimetric analysis (TGA) confirmed the drug anions were successfully intercalated in the interlayer space of LZH. Specific surface area of the obtained compound was increased compared to that of the host due to the different pore textures between the two materials. CFX anions were slowly released over 80 hours in phosphate-buffered saline (PBS) solution due to strong interactions that occurred between the intercalated anions and the host lattices. The intercalation compound demonstrated enhanced antiproliferative effects towards A549 cancer cells compared to the toxicity of CFX alone. Conclusions Strong host-guest interactions between the LZH lattice and the CFX anion give rise to a new intercalation compound that demonstrates sustained release mode and enhanced toxicity effects towards A549 cell lines. These findings should serve as foundations towards further developments of the brucite-like host material in drug delivery systems. PMID:23849189

Study of the non-stationarity of the atmosphere of κ Cas. Ii. Variability of the H γ, H β, and H α wind-line profiles

NASA Astrophysics Data System (ADS)

Rzaev, A. Kh.

2017-10-01

We study the variability of the H γ, H β, and H α line profiles in the spectrum of the supergiant κ Cas. The variability pattern proved to be the same for all the lines considered: their profiles are superimposed by blueshifted, central, and redshifted emission. For H γ the positions of the emissions coincide with the positions of the corresponding emissions for He I λλ 5876, 6678 Å lines, and are equal to about -135 ± 30.0 km s-1, -20 ± 20 kms-1, and 135 ± 30.0 kms-1, respectively, whereas the three emissions in the H β profiles are fixed at about -170.0 ± 70.0 kms-1, 20 ± 30 kms-1, and 170.0 ± 70.0 km s-1, respectively. The positions of the blueshifted and central emissions for H α are the same as for H β, with additional blueshifted emission at -135.0 ± 30.0 kms-1, whereas no traces of emission can be seen in the red wing of the line. These emissions show up more conspicuously in wind lines, however, their traces can be seen in all photospheric lines. When passing from wind lines to photospheric lines the intensity of superimposed emission components decreases and the same is true for the absolute values of their positions in line wings expressed in terms of radial velocities. The V/ R variations of the lines studied found in the spectrum of κ Cas and the variability of the H α emission indicate that the star is a supergiant showing Be phenomenon.

Method and apparatus for reducing diffraction-induced damage in high power laser amplifier systems

DOEpatents

Campillo, Anthony J.; Newnam, Brian E.; Shapiro, Stanley L.; Terrell, Jr., N. James

1976-01-01

Self-focusing damage caused by diffraction in laser amplifier systems may be minimized by appropriately tailoring the input optical beam profile by passing the beam through an aperture having a uniform high optical transmission within a particular radius r.sub.o and a transmission which drops gradually to a low value at greater radii. Apertures having the desired transmission characteristics may readily be manufactured by exposing high resolution photographic films and plates to a diffuse, disk-shaped light source and mask arrangement.

Inversion of the anomalous diffraction approximation for variable complex index of refraction near unity. [numerical tests for water-haze aerosol model

NASA Technical Reports Server (NTRS)

Smith, C. B.

1982-01-01

The Fymat analytic inversion method for retrieving a particle-area distribution function from anomalous diffraction multispectral extinction data and total area is generalized to the case of a variable complex refractive index m(lambda) near unity depending on spectral wavelength lambda. Inversion tests are presented for a water-haze aerosol model. An upper-phase shift limit of 5 pi/2 retrieved an accurate peak area distribution profile. Analytical corrections using both the total number and area improved the inversion.

Combined Ultraviolet and Optical Spectra of 48 Low-Redshift QSOs and the Relation of the Continuum and Emission-Line Properties

NASA Astrophysics Data System (ADS)

Corbin, Michael R.; Boroson, Todd A.

1996-11-01

We present combined ultraviolet and optical spectra of 48 QSOs and Seyfert 1 galaxies in the redshift range 0.034-0.774. The UV spectra were obtained non-simultaneously with the optical and are derived from archival Hubble Space Telescope (HST) Faint Object Spectrograph and International Ultraviolet Explorer (IUE) observations. The sample consists of 22 radio- quiet objects, 12 flat radio spectrum radio-loud objects, and 14 steep radio spectrum objects, and it covers approximately 2.5 decades in ultraviolet continuum luminosity. The sample objects are among the most luminous known in this redshift range and include 3C 273 and Fairall 9, as well as many objects discovered in the Bright Quasar Survey. We measure and compare an array of emission-line and continuum parameters, including 2 keV X-ray luminosities derived from the Einstein database. We examine individual correlations and also apply a principal components analysis (PCA) in an effort to determine the underlying sources of variance among these observables. Our main results are as follows. 1. The C IV λ1549 profile asymmetry is correlated with the UV continuum luminosity measured at the position of that line, such that increasing continuum luminosity produces increasing redward asymmetry. This is the same correlation found between Hβ asymmetry and 2 keV luminosity in a larger sample of objects and appears to be followed by both radio-loud and radio-quiet sources. The C IV profile asymmetry is also correlated with the FWZI of the Lyα profile, with more redward asymmetric profiles associated with wider profile bases. The PCA reveals that the correlated increase in luminosity, C IV redward asymmetry, and profile base width accounts for over half the statistical variance in the sample. 2. There is a statistically significant difference between the FWZI distributions of the Lyα and Hβ lines, such that the former is wider on average by ~10^4^ km s^-1^. The FWHM values of the broad Hβ line are weakly correlated with those of C IV λ1549 and Lyα, and in contrast to the FWZI values the Hβ profiles are wider. Measures of the asymmetry of the Hβ and C IV profiles also show a weak correlation. The wavelength centroids at 3/4 maximum of the Lyα and C IV lines also show average blueshifts ~50-200 km s^-1^ from [O III] λ5007, versus an average redshift of 75 km s^-1^ for broad Hβ. 3. There is no clear evidence of narrow components to the stronger UV lines, even among objects in which the optical narrow lines including [O III] λλ4959, 5007 are unusually strong. We measure the average fractional contributions of such components to the Lyα and C III] λ1909 lines to be ~4%-5%, consistent with the findings from smaller samples. However, a sizable fraction (50%) of radio-loud objects display a narrow component of He II λ1640, the same as in the QSO population at intermediate redshifts, and such a component is likely to contribute to the other UV lines. We interpret the first result as the effect of a black hole mass/luminosity relation in which the profile widths and redward asymmetries are produced respectively by the virialized motions and gravitational redshift associated with 10^9^-10^10^ M_sun_ holes. This does not explain the cases of blueward profile asymmetries and blueshifted profile peaks, which require an effect acting oppositely to gravitational redshift. The peak redshift differences and relative weakness of the correlations between the UV profile widths and asymmetries and those of Hβ suggests a stratified ionization structure of the broad-line region (BLR), consistent with the variability studies of Seyfert 1 galaxies. Continuum variability and the dynamical evolution of the BLR gas may also influence these results. The difference between the Lyα and Hβ FWZI values provides additional evidence of an optically thin very broad line region (VBLR) lying interior to an intermediate line region (ILR) producing the profile cores. The smaller average FWHM values of the UV lines compared to Hβ indicate that they have a higher relative contribution of ILR emission, versus a more dominant VBLR component in the Balmer lines. The narrow He II λ1640 feature of radio-loud objects is likely associated with the inner regions of extended (100 kpc) ionized halos that are not present around radio-quiet objects, and which appear to be best explained as cooling flows around the QSO host galaxies.

Errors associated with fitting Gaussian profiles to noisy emission-line spectra

NASA Technical Reports Server (NTRS)

Lenz, Dawn D.; Ayres, Thomas R.

1992-01-01

Landman et al. (1982) developed prescriptions to predict profile fitting errors for Gaussian emission lines perturbed by white noise. We show that their scaling laws can be generalized to more complicated signal-dependent 'noise models' of common astronomical detector systems.

An atlas of synthetic line profiles of Planetary Nebulae

NASA Astrophysics Data System (ADS)

Morisset, C.; Stasinska, G.

2008-04-01

We have constructed a grid of photoionization models of spherical, elliptical and bipolar planetary nebulae. Assuming different velocity fields, we have computed line profiles corresponding to different orientations, slit sizes and positions. The atlas is meant both for didactic purposes and for the interpretation of data on real nebulae. As an application, we have shown that line profiles are often degenerate, and that recovering the geometry and velocity field from observations requires lines from ions with different masses and different ionization potentials. We have also shown that the empirical way to measure mass-weighted expansion velocities from observed line widths is reasonably accurate if considering the HWHM. For distant nebulae, entirely covered by the slit, the unknown geometry and orientation do not alter the measured velocities statistically. The atlas is freely accessible from internet. The Cloudy_3D suite and the associated VISNEB tool are available on request.

Physics Notes.

ERIC Educational Resources Information Center

School Science Review, 1982

1982-01-01

Outlines methodology, demonstrations, and materials including: an inexpensive wave machine; speed of sound in carbon dioxide; diffraction grating method for measuring spectral line wavelength; linear electronic thermometer; analogy for bromine diffusion; direct reading refractice index meter; inexpensive integrated circuit spectrophotometer; and…

The FTS atomic spectrum tool (FAST) for rapid analysis of line spectra

NASA Astrophysics Data System (ADS)

Ruffoni, M. P.

2013-07-01

The FTS Atomic Spectrum Tool (FAST) is an interactive graphical program designed to simplify the analysis of atomic emission line spectra obtained from Fourier transform spectrometers. Calculated, predicted and/or known experimental line parameters are loaded alongside experimentally observed spectral line profiles for easy comparison between new experimental data and existing results. Many such line profiles, which could span numerous spectra, may be viewed simultaneously to help the user detect problems from line blending or self-absorption. Once the user has determined that their experimental line profile fits are good, a key feature of FAST is the ability to calculate atomic branching fractions, transition probabilities, and oscillator strengths-and their uncertainties-which is not provided by existing analysis packages. Program SummaryProgram title: FAST: The FTS Atomic Spectrum Tool Catalogue identifier: AEOW_v1_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEOW_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License version 3 No. of lines in distributed program, including test data, etc.: 293058 No. of bytes in distributed program, including test data, etc.: 13809509 Distribution format: tar.gz Programming language: C++. Computer: Intel x86-based systems. Operating system: Linux/Unix/Windows. RAM: 8 MB minimum. About 50-200 MB for a typical analysis. Classification: 2.2, 2.3, 21.2. Nature of problem: Visualisation of atomic line spectra including the comparison of theoretical line parameters with experimental atomic line profiles. Accurate intensity calibration of experimental spectra, and the determination of observed relative line intensities that are needed for calculating atomic branching fractions and oscillator strengths. Solution method: FAST is centred around a graphical interface, where a user may view sets of experimental line profiles and compare them to calculated data (such as from the Kurucz database [1]), predicted line parameters, and/or previously known experimental results. With additional information on the spectral response of the spectrometer, obtained from a calibrated standard light source, FT spectra may be intensity calibrated. In turn, this permits the user to calculate atomic branching fractions and oscillator strengths, and their respective uncertainties. Running time: Open ended. Defined by the user. References: [1] R.L. Kurucz (2007). URL http://kurucz.harvard.edu/atoms/.

X-Ray Diffraction Wafer Mapping Method for Rhombohedral Super-Hetero-Epitaxy

NASA Technical Reports Server (NTRS)

Park, Yoonjoon; Choi, Sang Hyouk; King, Glen C.; Elliott, James R.; Dimarcantonio, Albert L.

2010-01-01

A new X-ray diffraction (XRD) method is provided to acquire XY mapping of the distribution of single crystals, poly-crystals, and twin defects across an entire wafer of rhombohedral super-hetero-epitaxial semiconductor material. In one embodiment, the method is performed with a point or line X-ray source with an X-ray incidence angle approximating a normal angle close to 90 deg, and in which the beam mask is preferably replaced with a crossed slit. While the wafer moves in the X and Y direction, a narrowly defined X-ray source illuminates the sample and the diffracted X-ray beam is monitored by the detector at a predefined angle. Preferably, the untilted, asymmetric scans are of {440} peaks, for twin defect characterization.

Optical imaging using spatial grating effects in ferrofluids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dave, Vishakha; Virpura, Hiral; Patel, Rajesh, E-mail: rjp@mkbhavuni.edu.in

2015-06-24

Under the effect of magnetic field the magnetic nanoparticles of the ferrofluid tend to align in the direction of the magnetic field. This alignment of the magnetic nanoparticles behaves as a spatial grating and diffract light, when light is propagating perpendicular to the direction of the applied magnetic field. The chains of the magnetic nanoparticles represents a linear series of fringes like those observed in a grating/wire. Under applied magnetic field the circular beam of light transforms into a prominent diffraction line in the direction perpendicular to the applied magnetic field. This diffracted light illuminates larger area on the screen.more » This behavior can be used as magneto controlled illumination of the object and image analysis.« less

Can commonly used profile planes be used to evaluate changes in lower lip position?

PubMed

Buschang, Peter H; Fretty, Kimberly; Campbell, Phillip M

2011-07-01

To determine the validity of five profile planes commonly used to describe the horizontal changes of the lower lip during orthodontic treatment. Pretreatment and posttreatment cephalograms of 79 patients (12.4 ± 2.8 years of age) were evaluated. Lower lip (labrale inferiorus) changes over time were measured relative to the Rickett's E-line, Steiner's S1-line, Burstone's B-line, Sushner's S2-line, and Holdaway's H-line. As an independent measure of actual horizontal lip changes, the labrale inferiorus was measured relative to a stable reference plane registered on the sella and oriented on the SN-7°. The lower lip actually moved anteriorly 2.35 ± 3.35 mm during orthodontic treatment; the five profile planes indicated that the lower lip moved to a more retrusive, posterior position. The five profile planes also showed no statistically significant sex differences in terms of the treatment changes that occurred, while the actual lip changes showed that males exhibited significantly greater changes than females. Actual treatment changes showed that the lower lip moved to a more protrusive position with nonextraction than with extraction treatments, changes that were not evident based on the five profile lines. While lip changes based on the five profile planes demonstrated moderately high to high intercorrelations ranging from 0.81 to 0.97, they showed only weak correlations (r < .35) with the actual horizontal changes of the labrale inferiorus. While all five planes measured similar aspects of positional change, none of them closely reflected the actual lower lip changes that occurred. These planes should not be used to measure changes in lip position that occur during treatment.

D2O self-broadening study in 2.5 μ

NASA Astrophysics Data System (ADS)

Lavrentieva, N.; Lugovskoi, A.; Sinitsa, L.; Sherbakov, A.; Svetlichny, O.

2014-11-01

The absorption spectra of the D2O monomer in 3600…4200 cm-1 were recorded using Fourier Transform spectrometer FS-125M at room temperature and pressure of 15 and 33 mbar with spectral resolution of 0.03 cm-1 using 2.5 cm long absorption cell. Strong unblended D2O lines lying on the wing of the H2O stretching band were used to determine the line broadening parameters. They were determined from the line profile by Program VxpProfile. The differences between fitted line profiles and experimental ones do not exceed 2%. Registered D2O lines belong to (011) - (000) and (110) - (000) bands of the second triad. Self-broadening coefficients vary from 0.27 cm-1/atm to 0.445 cm-1/atm and they exceed 3 times the D2O-N2 line broadening coefficients in the v3. Calculations of self-broadening coefficients of the D2O lines were performed using semiempirical method based on the impact theory of broadening and included the correction factors. The calculated results well agree with experimental data.

Application of Raman spectroscopy for on-line monitoring of low dose blend uniformity.

PubMed

Hausman, Debra S; Cambron, R Thomas; Sakr, Adel

2005-07-14

On-line Raman spectroscopy was used to evaluate the effect of blending time on low dose, 1%, blend uniformity of azimilide dihydrochloride. An 8 qt blender was used for the experiments and instrumented with a Raman probe through the I-bar port. The blender was slowed to 6.75 rpm to better illustrate the blending process (normal speed is 25 rpm). Uniformity was reached after 20 min of blending at 6.75 rpm (135 revolutions or 5.4 min at 25 rpm). On-line Raman analysis of blend uniformity provided more benefits than traditional thief sampling and off-line analysis. On-line Raman spectroscopy enabled generating data rich blend profiles, due to the ability to collect a large number of samples during the blending process (sampling every 20s). In addition, the Raman blend profile was rapidly generated, compared to the lengthy time to complete a blend profile with thief sampling and off-line analysis. The on-line Raman blend uniformity results were also significantly correlated (p-value < 0.05) to the HPLC uniformity results of thief samples.

Discovery of the Red-Skewed K-alpha Iron Line in Cyg X-2 with Suzaku

NASA Technical Reports Server (NTRS)

Shaposhnikov, Nikolai; Titarchuk, Lev; Laurent, Philippe

2008-01-01

We report on the Suzaku observation of neutron star low-mass X-ray binary Cygnus X-2 which reveals strong iron K-alpha emission line. The line profile shows a prominent red wing extending down to 4 keV. This discovery increases the number of neutron star sources where red-skewed iron lines were observed and strongly suggests that this phenomenon is common not only in black holes but also in other types of compact objects. We examine the line profile by fitting it with the model which attributes its production to the relativistic effects due to disk reflection of X-ray radiation. We also apply an alternative model where the red wing is a result of down-scattering effect of the first order with respect to electron velocity in the wind outflow. Both models describe adequately the observed line profile. However, the X-ray variability in a state similar to that in the Suzaku observation which we establish by analysing RXTE observation favors the wind origin of the line formation.

Refractive-index profile and physical process determination in thick gratings in electrooptic crystals

NASA Technical Reports Server (NTRS)

Su, S. F.; Gaylord, T. K.

1976-01-01

A method for determining the refractive index profile of thick phase gratings in linear electrooptic crystals is presented. This method also determines the effective photovoltaic electric field and the relative contributions of diffusion and drift during hologram recording. The method requires only a knowledge of the modulation ratio during hologram recording and the fundamental and the higher-order diffraction efficiencies of the grating. As an illustration of the method, the refractive index profile, the effective photovoltaic field, and the relative contributions of diffusion and drift are determined from experimental measurements for a lithium niobate holographic grating.

Method and apparatus for detecting flaws and defects in heat seals

NASA Technical Reports Server (NTRS)

Rai, Kula R. (Inventor); Lew, Thomas M. (Inventor); Sinclair, Robert B. (Inventor)

1993-01-01

Flaws and defects in heat seals formed between sheets of translucent film are identified by optically examining consecutive lateral sections of the seal along the seal length. Each lateral seal section is illuminated and an optical sensor array detects the intensity of light transmitted through the seal section for the purpose of detecting and locating edges in the heat seal. A line profile for each consecutive seal section is derived having an amplitude proportional to the change in light intensity across the seal section. Instances in the derived line profile where the amplitude is greater than a threshold level indicate the detection of a seal edge. The detected edges in each derived line profile are then compared to a preset profile edge standard to identify the existence of a flaw or defect.

Evaluating the use of high speed laser line sensors for improved rideability measurement.

DOT National Transportation Integrated Search

2016-09-01

This research project compared rideability readings and repeatability for both point laser and line laser systems on the high-speed profiler. Both systems were Dynatest 5051 Mark III Road Surface Profilers, one equipped with single point lasers and t...

Single-slit electron diffraction with Aharonov-Bohm phase: Feynman's thought experiment with quantum point contacts.

PubMed

Khatua, Pradip; Bansal, Bhavtosh; Shahar, Dan

2014-01-10

In a "thought experiment," now a classic in physics pedagogy, Feynman visualizes Young's double-slit interference experiment with electrons in magnetic field. He shows that the addition of an Aharonov-Bohm phase is equivalent to shifting the zero-field wave interference pattern by an angle expected from the Lorentz force calculation for classical particles. We have performed this experiment with one slit, instead of two, where ballistic electrons within two-dimensional electron gas diffract through a small orifice formed by a quantum point contact (QPC). As the QPC width is comparable to the electron wavelength, the observed intensity profile is further modulated by the transverse waveguide modes present at the injector QPC. Our experiments open the way to realizing diffraction-based ideas in mesoscopic physics.

In situ x-ray diffraction measurements of the capillary fountain jet produced via ultrasonic atomization.

PubMed

Yano, Yohko F; Douguchi, Junya; Kumagai, Atsushi; Iijima, Takao; Tomida, Yukinobu; Miyamoto, Toshiaki; Matsuura, Kazuo

2006-11-07

In situ x-ray diffraction measurements were carried out for investigating the liquid structure in the ultrasonic fountain jet to consider the mechanism of the "ultrasonic ethanol separation" reported by Sato et al. [J. Chem. Phys. 114, 2382 (2001)]. For pure liquids (water and ethanol), it was found that the high frequency ultrasound does not affect the liquid structure microscopically. For the 20 mol % ethanol-water mixture, the estimated ethanol mole fraction in the ultrasonic fountain jet by using the position of the main maximum in the x-ray diffraction profile coincided with that in the reservoir. This result suggests that the ethanol separation is not caused by any distorted liquid structure under the ultrasound irradiation and occurs when or after the generation of the liquid droplet mist.

In situ x-ray diffraction measurements of the capillary fountain jet produced via ultrasonic atomization

NASA Astrophysics Data System (ADS)

Yano, Yohko F.; Douguchi, Junya; Kumagai, Atsushi; Iijima, Takao; Tomida, Yukinobu; Miyamoto, Toshiaki; Matsuura, Kazuo

2006-11-01

In situ x-ray diffraction measurements were carried out for investigating the liquid structure in the ultrasonic fountain jet to consider the mechanism of the "ultrasonic ethanol separation" reported by Sato et al. [J. Chem. Phys. 114, 2382 (2001)]. For pure liquids (water and ethanol), it was found that the high frequency ultrasound does not affect the liquid structure microscopically. For the 20mol% ethanol-water mixture, the estimated ethanol mole fraction in the ultrasonic fountain jet by using the position of the main maximum in the x-ray diffraction profile coincided with that in the reservoir. This result suggests that the ethanol separation is not caused by any distorted liquid structure under the ultrasound irradiation and occurs when or after the generation of the liquid droplet mist.

Neutron and X-ray Microbeam Diffraction Studies around a Fatigue-Crack Tip after Overload

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Sooyeol; Barabash, Rozaliya; Chung, Jin-Seok

2008-01-01

An in-situ neutron diffraction technique was used to investigate the lattice-strain distributions and plastic deformation around a crack tip after overload. The lattice-strain profiles around a crack tip were measured as a function of the applied load during the tensile loading cycles after overload. Dislocation densities calculated from the diffraction peak broadening were presented as a function of the distance from the crack tip. Furthermore, the crystallographic orientation variations were examined near a crack tip using polychromatic X-ray microdiffraction combined with differential aperture microscopy. Crystallographic tilts are considerably observed beneath the surface around a crack tip, and these are consistentmore » with the high dislocation densities near the crack tip measured by neutron peak broadening.« less

Electron-beam lithography for micro and nano-optical applications

NASA Technical Reports Server (NTRS)

Wilson, Daniel W.; Muller, Richard E.; Echternach, Pierre M.

2005-01-01

Direct-write electron-beam lithography has proven to be a powerful technique for fabricating a variety of micro- and nano-optical devices. Binary E-beam lithography is the workhorse technique for fabricating optical devices that require complicated precision nano-scale features. We describe a bi-layer resist system and virtual-mark height measurement for improving the reliability of fabricating binary patterns. Analog E-beam lithography is a newer technique that has found significant application in the fabrication of diffractive optical elements. We describe our techniques for fabricating analog surface-relief profiles in E-beam resist, including some discussion regarding overcoming the problems of resist heating and charging. We also describe a multiple-field-size exposure scheme for suppression of field-stitch induced ghost diffraction orders produced by blazed diffraction gratings on non-flat substrates.

Laser fabrication of diffractive optical elements based on detour-phase computer-generated holograms for two-dimensional Airy beams.

PubMed

Călin, Bogdan-Ştefăniţă; Preda, Liliana; Jipa, Florin; Zamfirescu, Marian

2018-02-20

We have designed, fabricated, and tested an amplitude diffractive optical element for generation of two-dimensional (2D) Airy beams. The design is based on a detour-phase computer-generated hologram. Using laser ablation of metallic films, we obtained a 2  mm×2  mm diffractive optical element with a pixel of 5  μm×5  μm and demonstrated a fast, cheap, and reliable fabrication process. This device can modulate 2D Airy beams or it can be used as a UV lithography mask to fabricate a series of phase holograms for higher energy efficiency. Tests according to the premise and an analysis of the transverse profile and propagation are presented.

Microbial Community Profile of a Lead Service Line Removed from a Drinking Water Distribution System▿

PubMed Central

White, Colin; Tancos, Matthew; Lytle, Darren A.

2011-01-01

A corroded lead service line was removed from a drinking water distribution system, and the microbial community was profiled using 16S rRNA gene techniques. This is the first report of the characterization of a biofilm on the surface of a corroded lead drinking water service line. The majority of phylotypes have been linked to heavy-metal-contaminated environments. PMID:21652741

High-Resolution Detector For X-Ray Diffraction

NASA Technical Reports Server (NTRS)

Carter, Daniel C.; Withrow, William K.; Pusey, Marc L.; Yost, Vaughn H.

1988-01-01

Proposed x-ray-sensitive imaging detector offers superior spatial resolution, counting-rate capacity, and dynamic range. Instrument based on laser-stimulated luminescence and reusable x-ray-sensitive film. Detector scans x-ray film line by line. Extracts latent image in film and simultaneously erases film for reuse. Used primarily for protein crystallography. Principle adapted to imaging detectors for electron microscopy and fluorescence spectroscopy and general use in astronomy, engineering, and medicine.

A User’s Manual for Fiber Diffraction: The Automated Picker and Huber Diffractometers

DTIC Science & Technology

1990-07-01

17 3. Layer line scan of degummed silk ( Bombyx mori ) ................................. 18...index (arbitrary units) Figure 3. Layer line scan of degummed silk ( Bombyx mori ) showing layers 0 through 6. If the fit is rejected, new values for... originally made at intervals larger than 0.010. The smoothing and interpolation is done by a least-squares polynomial fit to segments of the data. The number

Light Management in Transparent Conducting Oxides by Direct Fabrication of Periodic Surface Arrays

NASA Astrophysics Data System (ADS)

Eckhardt, S.; Sachse, C.; Lasagni, A. F.

Line- and hexagonal-like periodic textures were fabricated on aluminium zinc oxide (AZO) using direct laser interference patterning method. It was found that hexagonally patterned surfaces show a higher performance in both transparency and diffraction properties compared to line-like textured and non-patterned substrates. Furthermore, the electrical resistance of the processed AZO coated substrates remained below the tolerance values for transparent conducting electrodes.

Analysis of Short and Long Range Atomic Order in Nanocrystalline Diamonds with Application of Powder Diffractometry

NASA Technical Reports Server (NTRS)

Palosz, B.; Grzanka, E.; Stelmakh, S.; Pielaszek, R.; Bismayer, U.; Neuefiend, J.; Weber, H.-P.; Proffen, T.; VonDreele, R.; Palosz, W.;

Low-kilovolt coherent electron diffractive imaging instrument based on a single-atom electron source

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lin, Chun-Yueh; Chang, Wei-Tse; Chen, Yi-Sheng

2016-03-15

In this work, a transmission-type, low-kilovolt coherent electron diffractive imaging instrument was constructed. It comprised a single-atom field emitter, a triple-element electrostatic lens, a sample holder, and a retractable delay line detector to record the diffraction patterns at different positions behind the sample. It was designed to image materials thinner than 3 nm. The authors analyzed the asymmetric triple-element electrostatic lens for focusing the electron beams and achieved a focused beam spot of 87 nm on the sample plane at the electron energy of 2 kV. High-angle coherent diffraction patterns of a suspended graphene sample corresponding to (0.62 Å){sup −1} were recorded. This workmore » demonstrated the potential of coherent diffractive imaging of thin two-dimensional materials, biological molecules, and nano-objects at a voltage between 1 and 10 kV. The ultimate goal of this instrument is to achieve atomic resolution of these materials with high contrast and little radiation damage.« less

The XMM-Newton Iron Line Profile of NGC 3783

NASA Technical Reports Server (NTRS)

Reeves, J. N.; Nandra, K.; George, I. M.; Pounds, K. A.; Turner, T. J.; Yaqoob, T.

2003-01-01

We report on observations of the iron K line in the nearby Seyfert 1 galaxy, NGC 3783, obtained in a long, 2 orbit (approx. 240 ks) XMM-Newton observation. The line profile obtained exhibits two strong narrow peaks at 6.4 keV and at 7.0 keV, with measured line equivalent widths of 120 and 35 eV respectively. The 6.4 keV emission is the K(alpha) line from near neutral Fe, whilst the 7.0 keV feature probably originates from a blend of the neutral Fe K(beta) line and the Hydrogen-like line of Fe at 6.97 keV. The relatively narrow velocity width of the K(alpha) line (approx. less than 5000 km/s), its lack of response to the continuum emission on short timescales and the detection of a neutral Compton reflection component are all consistent with a distant origin in Compton-thick matter such as the putative molecular torus. A strong absorption line from highly ionized iron (at 6.67 keV) is detected in the time-averaged iron line profile, whilst the depth of the feature appears to vary with time, being strongest when the continuum flux is higher. The iron absorption line probably arises from the highest ionization component of the known warm absorber in NGC 3783, with an ionization of log xi approx 3 and column density of N(sub H) approx. 5 x 10(exp 22)/sq cm and may originate from within 0.1 pc of the nucleus. A weak red-wing to the iron K line profile is also detected below 6.4 keV. However when the effect of the highly ionized warm absorber on the underlying continuum is taken into account, the requirement for a relativistic iron line component from the inner disk is reduced.

Impacts of fragmented accretion streams onto classical T Tauri stars: UV and X-ray emission lines

NASA Astrophysics Data System (ADS)

Colombo, S.; Orlando, S.; Peres, G.; Argiroffi, C.; Reale, F.

2016-10-01

Context. The accretion process in classical T Tauri stars (CTTSs) can be studied through the analysis of some UV and X-ray emission lines which trace hot gas flows and act as diagnostics of the post-shock downfalling plasma. In the UV-band, where higher spectral resolution is available, these lines are characterized by rather complex profiles whose origin is still not clear. Aims: We investigate the origin of UV and X-ray emission at impact regions of density structured (fragmented) accretion streams. We study if and how the stream fragmentation and the resulting structure of the post-shock region determine the observed profiles of UV and X-ray emission lines. Methods: We modeled the impact of an accretion stream consisting of a series of dense blobs onto the chromosphere of a CTTS through two-dimensional (2D) magnetohydrodynamic (MHD) simulations. We explored different levels of stream fragmentation and accretion rates. From the model results, we synthesize C IV (1550 Å) and O VIII (18.97 Å) line profiles. Results: The impacts of accreting blobs onto the stellar chromosphere produce reverse shocks propagating through the blobs and shocked upflows. These upflows, in turn, hit and shock the subsequent downfalling fragments. As a result, several plasma components differing for the downfalling velocity, density, and temperature are present altoghether. The profiles of C IV doublet are characterized by two main components: one narrow and redshifted to speed ≈ 50 km s-1 and the other broader and consisting of subcomponents with redshift to speed in the range 200-400 km s-1. The profiles of O VIII lines appear more symmetric than C IV and are redshifted to speed ≈ 150 km s-1. Conclusions: Our model predicts profiles of C IV line remarkably similar to those observed and explains their origin in a natural way as due to stream fragmentation. Movies are available at http://www.aanda.org

PSF modeling by spikes simulations and wings measurements for the MOONS multi fiber spectrograph

NASA Astrophysics Data System (ADS)

Li Causi, G.; Lee, D.; Vitali, F.; Royer, F.; Oliva, E.

2016-08-01

The optical design of MOONS, the next generation thousand-fiber NIR spectrograph for the VLT, involves both on-axis reflective collimators and on-axis very fast reflective cameras, which yields both beam obstruction, due to fiber slit and detector support, and image spread, due to propagation within detector substrate. The need to model and control i) the effect of the diffraction spikes produced by these obstructions, ii) the detector-induced shape variation of the Point Spread Function (PSF), and iii) the intensity profile of the PSF wings, leads us to perform both simulations and lab measurements, in order to optimize the spider design and built a reliable PSF model, useful for simulate realistic raw images for testing the data reduction. Starting from the unobstructed PSF variation, as computed with the ZEMAX software, we numerically computed the diffraction spikes for different spider shapes, to which we added the PSF wing profile, as measured on a sample of the MOONS VPH diffraction grating. Finally, we implemented the PSF defocusing due to the thick detector (for the visible channel), we convolved the PSF with the fiber core image, and we added the optical ghosts, so finally obtaining a detailed and realistic PSF model, that we use for spectral extraction testing, cross talk estimation, and sensitivity predictions.

Near-surface density profiling of Fe ion irradiated Si (100) using extremely asymmetric x-ray diffraction by variation of the wavelength

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khanbabaee, B., E-mail: khanbabaee@physik.uni-siegen.de; Pietsch, U.; Facsko, S.

2014-10-20

In this work, we report on correlations between surface density variations and ion parameters during ion beam-induced surface patterning process. The near-surface density variations of irradiated Si(100) surfaces were investigated after off-normal irradiation with 5 keV Fe ions at different fluences. In order to reduce the x-ray probing depth to a thickness below 5 nm, the extremely asymmetrical x-ray diffraction by variation of wavelength was applied, exploiting x-ray refraction at the air-sample interface. Depth profiling was achieved by measuring x-ray rocking curves as function of varying wavelengths providing incidence angles down to 0°. The density variation was extracted from the deviationsmore » from kinematical Bragg angle at grazing incidence angles due to refraction of the x-ray beam at the air-sample interface. The simulations based on the dynamical theory of x-ray diffraction revealed that while a net near-surface density decreases with increasing ion fluence which is accompanied by surface patterning, there is a certain threshold of ion fluence to surface density modulation. Our finding suggests that the surface density variation can be relevant with the mechanism of pattern formation.« less

Influence of in vivo growth on human glioma cell line gene expression: Convergent profiles under orthotopic conditions

PubMed Central

Camphausen, Kevin; Purow, Benjamin; Sproull, Mary; Scott, Tamalee; Ozawa, Tomoko; Deen, Dennis F.; Tofilon, Philip J.

2005-01-01

Defining the molecules that regulate tumor cell survival is an essential prerequisite for the development of targeted approaches to cancer treatment. Whereas many studies aimed at identifying such targets use human tumor cells grown in vitro or as s.c. xenografts, it is unclear whether such experimental models replicate the phenotype of the in situ tumor cell. To begin addressing this issue, we have used microarray analysis to define the gene expression profile of two human glioma cell lines (U251 and U87) when grown in vitro and in vivo as s.c. or as intracerebral (i.c.) xenografts. For each cell line, the gene expression profile generated from tissue culture was significantly different from that generated from the s.c. tumor, which was significantly different from those grown i.c. The disparity between the i.c gene expression profiles and those generated from s.c. xenografts suggests that whereas an in vivo growth environment modulates gene expression, orthotopic growth conditions induce a different set of modifications. In this study the U251 and U87 gene expression profiles generated under the three growth conditions were also compared. As expected, the profiles of the two glioma cell lines were significantly different when grown as monolayer cultures. However, the glioma cell lines had similar gene expression profiles when grown i.c. These results suggest that tumor cell gene expression, and thus phenotype, as defined in vitro is affected not only by in vivo growth but also by orthotopic growth, which may have implications regarding the identification of relevant targets for cancer therapy. PMID:15928080

Analysis of a Novel Diffractive Scanning Wire Beam Position Monitor (BPM) for Discriminative Profiling of Electron Vs. X Ray Beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tatchyn, Roman; /SLAC

2011-09-01

Recent numerical studies of Free Electron Lasers (FELs) operating in the Self Amplified Spontaneous Emission (SASE) regime indicate a large sensitivity of the gain to the degree of transverse overlap (and associated phase coherence) between the electron and photon beams traveling down the insertion device. Simulations of actual systems imply that accurate detection and correction for this relative loss of overlap, rather than correction for the absolute departure of the electron beam from a fixed axis, is the preferred function of an FEL amplifier's Beam Position Monitor (BPM) and corrector systems. In this note we propose a novel diffractive BPMmore » with the capability of simultaneously detecting and resolving the absolute (and relative) transverse positions and profiles of electron and x-ray beams co-propagating through an undulator. We derive the equations governing the performance of the BPM and examine its predicted performance for the SLAC Linac Coherent Light Source (LCLS), viz., for profiling multi-GeV electron bunches co-propagating with one-to-several-hundred keV x-ray beams. Selected research and development (r&d) tasks for fabricating and testing the proposed BPM are discussed.« less

Profiling pleural effusion cells by a diffraction imaging method

NASA Astrophysics Data System (ADS)

Al-Qaysi, Safaa; Hong, Heng; Wen, Yuhua; Lu, Jun Q.; Feng, Yuanming; Hu, Xin-Hua

2018-02-01

Assay of cells in pleural effusion (PE) is an important means of disease diagnosis. Conventional cytology of effusion samples, however, has low sensitivity and depends heavily on the expertise of cytopathologists. We applied a polarization diffraction imaging flow cytometry method on effusion cells to investigate their features. Diffraction imaging of the PE cell samples has been performed on 6000 to 12000 cells for each effusion cell sample of three patients. After prescreening to remove images by cellular debris and aggregated non-cellular particles, the image textures were extracted with a gray level co-occurrence matrix (GLCM) algorithm. The distribution of the imaged cells in the GLCM parameters space was analyzed by a Gaussian Mixture Model (GMM) to determine the number of clusters among the effusion cells. These results yield insight on textural features of diffraction images and related cellular morphology in effusion samples and can be used toward the development of a label-free method for effusion cells assay.

Toward in situ x-ray diffraction imaging at the nanometer scale

NASA Astrophysics Data System (ADS)

Zatsepin, Nadia A.; Dilanian, Ruben A.; Nikulin, Andrei Y.; Gable, Brian M.; Muddle, Barry C.; Sakata, Osami

2008-08-01

We present the results of preliminary investigations determining the sensitivity and applicability of a novel x-ray diffraction based nanoscale imaging technique, including simulations and experiments. The ultimate aim of this nascent technique is non-destructive, bulk-material characterization on the nanometer scale, involving three dimensional image reconstructions of embedded nanoparticles and in situ sample characterization. The approach is insensitive to x-ray coherence, making it applicable to synchrotron and laboratory hard x-ray sources, opening the possibility of unprecedented nanometer resolution with the latter. The technique is being developed with a focus on analyzing a technologically important light metal alloy, Al-xCu (where x is 2.0-5.0 %wt). The mono- and polycrystalline samples contain crystallographically oriented, weakly diffracting Al2Cu nanoprecipitates in a sparse, spatially random dispersion within the Al matrix. By employing a triple-axis diffractometer in the non-dispersive setup we collected two-dimensional reciprocal space maps of synchrotron x-rays diffracted from the Al2Cu nanoparticles. The intensity profiles of the diffraction peaks confirmed the sensitivity of the technique to the presence and orientation of the nanoparticles. This is a fundamental step towards in situ observation of such extremely sparse, weakly diffracting nanoprecipitates embedded in light metal alloys at early stages of their growth.

The Ly(alpha) Line Profiles of Ultraluminous Infrared Galaxies: Fast Winds and Lyman Continuum Leakage

NASA Technical Reports Server (NTRS)

Martin, Crystal L.; Dijkstra, Mark; Henry, Alaina L.; Soto, Kurt T.; Danforth, Charles W.; Wong, Joseph

2015-01-01

We present new Hubble Space Telescope Cosmic Origins Spectrograph far-ultraviolet (far-UV) spectroscopy and Keck Echellete optical spectroscopy of 11 ultraluminous infrared galaxies (ULIRGs), a rare population of local galaxies experiencing massive gas inflows, extreme starbursts, and prominent outflows. We detect Ly(alpha) emission from eight ULIRGs and the companion to IRAS09583+4714. In contrast to the P Cygni profiles often seen in galaxy spectra, the Ly(alpha) profiles exhibit prominent, blueshifted emission out to Doppler shifts exceeding -1000 km/s in three H II-dominated and two AGN-dominated ULIRGs. To better understand the role of resonance scattering in shaping the Ly(alpha) line profiles, we directly compare them to non-resonant emission lines in optical spectra. We find that the line wings are already present in the intrinsic nebular spectra, and scattering merely enhances the wings relative to the line core. The Ly(alpha) attenuation (as measured in the COS aperture) ranges from that of the far-UV continuum to over 100 times more. A simple radiative transfer model suggests the Ly(alpha) photons escape through cavities which have low column densities of neutral hydrogen and become optically thin to the Lyman continuum in the most advanced mergers. We show that the properties of the highly blueshifted line wings on the Ly(alpha) and optical emission-line profiles are consistent with emission from clumps of gas condensing out of a fast, hot wind. The luminosity of the Ly(alpha) emission increases nonlinearly with the ULIRG bolometric luminosity and represents about 0.1-1% of the radiative cooling from the hot winds in the H II-dominated ULIRGs.

Body-centered orthorhombic C 16 : A novel topological node-line semimetal

DOE PAGES

Wang, Jian -Tao; Weng, Hongming; Nie, Simin; ...

2016-05-11

We identify by ab initio calculations a novel topological semimetal carbon phase in all-sp 2 bonding networks with a 16-atom body-centered orthorhombic unit cell, termed bco-C 16. Total-energy calculations show that bco-C 16 is comparable to solid fcc-C 60 in energetic stability, and phonon and molecular dynamics simulations confirm its dynamical stability. This all-sp 2 carbon allotrope can be regarded as a three-dimensional modification of graphite, and its simulated x-ray diffraction (XRD) pattern matches well a previously unexplained diffraction peak in measured XRD spectra of detonation and chimney soot, indicating its presence in the specimen. Electronic band structure calculations revealmore » that bco-C 16 is a topological node-line semimetal with a single nodal ring. Lastly, these findings establish a novel carbon phase with intriguing structural and electronic properties of fundamental significance and practical interest.« less

Femtosecond laser induced tunable surface transformations on (111) Si aided by square grids diffraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Han, Weina; Jiang, Lan; Li, Xiaowei, E-mail: lixiaowei@bit.edu.cn

We report an extra freedom to modulate the femtosecond laser energy distribution to control the surface ablated structures through a copper-grid mask. Due to the reduced deposited pulse energy by changing the scanning speed or the pulse fluence, a sequential evolution of three distinctly different surface patterns with periodic distributions is formed, namely, striped ripple lines, ripple microdots, and surface modification. By changing the scanning speed, the number of the multiple dots in a lattice can be modulated. Moreover, by exploring the ablation process through the copper grid mask, it shows an abnormal enhanced ablation effect with strong dependence ofmore » the diffraction-aided fs laser ablated surface structures on polarization direction. The sensitivity shows a quasi-cosinusoid-function with a periodicity of π/2. Particularly, the connection process of striped ripple lines manifests a preferential formation direction with the laser polarization.« less

EP Profiles Inventor Mark Sherron

ERIC Educational Resources Information Center

Williams, John M.

2006-01-01

This article profiles Mark Jerome Sherron, inventor of the ALLIES Line of electronic sensors for blind and visually-impaired people. Featuring the American Liquid Level Indicator electronic sensor (ALLI), Sherron's ALLIES product line also includes the Light Intensity Level Indicator (LILI), a multi-function electronic light sensor for electronic…

20. GEOLOGY, PLAN AND PROFILE, SHOWING LINED AND UNLINED SECTIONS, ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

20. GEOLOGY, PLAN AND PROFILE, SHOWING LINED AND UNLINED SECTIONS, AND DETAILED TYPICAL CROSS SECTIONS. Leeds, Hill, Barnard & Jewett drawing, no number, revised 3-20-42. - Salinas River Project, Cuesta Tunnel, Southeast of U.S. 101, San Luis Obispo, San Luis Obispo County, CA

Propagation of a laser beam in a plasma

NASA Technical Reports Server (NTRS)

Chapman, J. M.; Kevorkian, J.; Steinhauer, L. C.; Vagners, J.

1975-01-01

This paper shows that for a nonabsorbing medium with a prescribed index of refraction, the effects of beam stability, line focusing, and beam distortion can be predicted from simple ray optics. When the paraxial approximation is used, diffraction effects are examined for Gaussian, Lorentzian, and square beams. Most importantly, it is shown that for a Gaussian beam, diffraction effects can be included simply by adding imaginary solutions to the paraxial ray equations. Also presented are several procedures to extend the paraxial approximation so that the solution will have a domain of validity of greater extent.

Numerical investigation of diffraction of acoustic waves by phononic crystals

NASA Astrophysics Data System (ADS)

Moiseyenko, Rayisa P.; Declercq, Nico F.; Laude, Vincent

2012-05-01

Diffraction as well as transmission of acoustic waves by two-dimensional phononic crystals (PCs) composed of steel rods in water are investigated in this paper. The finite element simulations were performed in order to compute pressure fields generated by a line source that are incident on a finite size PC. Such field maps are analyzed based on the complex band structure for the infinite periodic PC. Finite size computations indicate that the exponential decrease of the transmission at deaf frequencies is much stronger than that in Bragg band gaps.

Retrieval of the atomic displacements in the crystal from the coherent X-ray diffraction pattern.

PubMed

Minkevich, A A; Köhl, M; Escoubas, S; Thomas, O; Baumbach, T

2014-07-01

The retrieval of spatially resolved atomic displacements is investigated via the phases of the direct(real)-space image reconstructed from the strained crystal's coherent X-ray diffraction pattern. It is demonstrated that limiting the spatial variation of the first- and second-order spatial displacement derivatives improves convergence of the iterative phase-retrieval algorithm for displacements reconstructions to the true solution. This approach is exploited to retrieve the displacement in a periodic array of silicon lines isolated by silicon dioxide filled trenches.

Theoretical analysis of microwave propagation

NASA Astrophysics Data System (ADS)

Parl, S.; Malaga, A.

1984-04-01

This report documents a comprehensive investigation of microwave propagation. The structure of line-of-sight multipath is determined and the impact on practical diversity is discussed. A new model of diffraction propagation for multiple rounded obstacles is developed. A troposcatter model valid at microwave frequencies is described. New results for the power impulse response, and the delay spread and Doppler spread are developed. A 2-component model separating large and small scale scatter effects is proposed. The prediction techniques for diffraction and troposcatter have been implemented in a computer program intended as a tool to analyze propagation experiments.

Non-LTE profiles of strong solar lines

NASA Technical Reports Server (NTRS)

Schneeberger, T. J.; Beebe, H. A.

1976-01-01

The complete linearization method is applied to the formation of strong lines in the solar atmosphere. Transitions in Na(I), Mg(I), Ca(I), Mg(II), and Ca(II) are computed with a standard atmosphere and microturbulent velocity model. The computed profiles are compared to observations at disk center.

Surface Relief of Mapping

NASA Astrophysics Data System (ADS)

Costa, Manuel F.; Almeida, Jose B.

1989-02-01

We will describe in this communication a noncont act method of measuring surface profile, it does not require any surface preparation, and it can be used with a very large range of surfaces from highly reflecting to non reflecting ones and as complex as textile surfaces. This method is reasonably immune to dispersion and diffraction, which usually make very difficult the application of non contact profilometry methods to a wide range of materials and situations, namely on quality control systems in industrial production lines. The method is based on the horizontal shift of the bright spot on a horizontal surface when this is illuminated with an oblique beam and moved vertically. in order to make the profilometry the sample is swept by an oblique light beam and the bright spot position is compared with a reference position. The bright spot must be as small as possible, particularly in very irregular surfaces; so the light beam diameter must be as small as possible and the incidence angle must not be too small. The sensivity of a system based on this method will be given, mostly, by the reception optical system.

Nano-hybrid carboxymethyl-hexanoyl chitosan modified with (3-aminopropyl)triethoxysilane for camptothecin delivery.

PubMed

Hsiao, Meng-Hsuan; Tung, Tsan-Hua; Hsiao, Chi-Sheng; Liu, Dean-Mo

2012-06-20

Silane-modified amphiphilic chitosan was synthesized by anchoring a silane coupling agent, (3-aminopropyl)triethoxysilane, to a novel amphiphilic carboxymethyl-hexanoyl chitosan (CHC). The chemical structure of this new organic-inorganic hybrid molecule was characterized by FTIR and 13C-, 29Si-nuclear magnetic resonance, while the structural evolution was examined using scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and dynamic light scattering (DLS). Experimental results indicated a self-assembly behaviour of molecules into nanoparticles with a stable polygonal geometry, consisting of ordered silane layers of 6 nm in thickness. The self-assembly property was found to be influenced by chemical composition and concentration of silane incorporated, while the size can be varied by the amount of anchored silane. It was also demonstrated that such vesicle exhibited excellent cytocompatibility and cellular internalization capability in ARPE-19 cell line, and presented well-controlled encapsulation and release profiles for (S)-(+)-camptothecin. These unique properties render it as a potential drug delivery nanosystem. Copyright © 2012 Elsevier Ltd. All rights reserved.

Stacking-fault strengthening of biomedical Co-Cr-Mo alloy via multipass thermomechanical processing.

PubMed

Yamanaka, Kenta; Mori, Manami; Sato, Shigeo; Chiba, Akihiko

2017-09-07

The strengthening of metallic biomaterials, such as Co-Cr-Mo and titanium alloys, is of crucial importance to the improvement of the durability of orthopedic implants. In the present study, we successfully developed a face-centered cubic (fcc) Co-Cr-Mo alloy with an extremely high yield strength (1400 MPa) and good ductility (12%) by multipass hot-rolling, which is suitable for industrial production, and examined the relevant strengthening mechanisms. Using an X-ray diffraction line-profile analysis, we revealed that a substantial increase in the number of stacking faults (SFs) in the fcc γ-matrix occurred at a greater height reduction (r), while physical modeling demonstrated that the contribution of the accumulated SFs (i.e., the reduction in SF spacing) with an increase in r successfully explains the entire strengthening behavior of the hot-rolled alloy. The present study sheds light on the importance of the SF strengthening mechanism, and will help to guide the design and manufacturing strategy for the high-strength Co-Cr-Mo alloys used in highly durable medical devices.

Nanostructure formation during accumulative roll bonding of commercial purity titanium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karimi, Mohsen, E-mail: m.karimi@shahroodut.ac.ir

2016-12-15

In this investigation, commercial purity titanium (CP–Ti) was subjected to accumulative roll bonding (ARB) process up to 8 cycles (equivalent strain of 6.4) at the ambient temperature. Transmission electron microscopy (TEM) and X–ray diffraction line profile analysis (XRDLPA) were utilized to investigate the microstructure and grain size evolution. Both characterization techniques could clarify the non–uniform microstructure in the early stages and the uniform microstructure in the final stages of the process. The effectiveness of ARB for the fabrication of the nano–grained structure in CP–Ti was revealed. It was found that the SFE is not the only factor affecting grain refinement,more » as compared with other studies on ARB of FCC materials. Influence of other factors such as the melting temperature and the crystalline structure of the material was determined on the grain refinement. - Highlights: •Nano–grained commercial purity titanium was produced by accumulative roll bonding. •TEM and XRDLPA were used for the characterization of the microstructure. •Important factors affecting the grain size of ARBed materials were discussed.« less

Partial dust obscuration in active galactic nuclei as a cause of broad-line profile and lag variability, and apparent accretion disc inhomogeneities

NASA Astrophysics Data System (ADS)

Gaskell, C. Martin; Harrington, Peter Z.

2018-04-01

The profiles of the broad emission lines of active galactic nuclei (AGNs) and the time delays in their response to changes in the ionizing continuum ("lags") give information about the structure and kinematics of the inner regions of AGNs. Line profiles are also our main way of estimating the masses of the supermassive black holes (SMBHs). However, the profiles often show ill-understood, asymmetric structure and velocity-dependent lags vary with time. Here we show that partial obscuration of the broad-line region (BLR) by outflowing, compact, dusty clumps produces asymmetries and velocity-dependent lags similar to those observed. Our model explains previously inexplicable changes in the ratios of the hydrogen lines with time and velocity, the lack of correlation of changes in line profiles with variability of the central engine, the velocity dependence of lags, and the change of lags with time. We propose that changes on timescales longer than the light-crossing time do not come from dynamical changes in the BLR, but are a natural result of the effect of outflowing dusty clumps driven by radiation pressure acting on the dust. The motion of these clumps offers an explanation of long-term changes in polarization. The effects of the dust complicate the study of the structure and kinematics of the BLR and the search for sub-parsec SMBH binaries. Partial obscuration of the accretion disc can also provide the local fluctuations in luminosity that can explain sizes deduced from microlensing.

Application of the Hartmann–Tran profile to precise experimental data sets of 12C 2H 2

DOE PAGES

Forthomme, D.; Cich, M. J.; Twagirayezu, S.; ...

2015-06-25

Self- and nitrogen-broadened line shape data for the P e(11) line of the ν₁ + ν₃ band of acetylene, recorded using a frequency comb-stabilized laser spectrometer, have been analyzed using the Hartmann–Tran profile (HTP) line shape model in a multispectrum fitting. In total, the data included measurements recorded at temperatures between 125 K and 296 K and at pressures between 4 and 760 Torr. New, sub-Doppler, frequency comb-referenced measurements of the positions of multiple underlying hot band lines have also been made. These underlying lines significantly affect the P e(11) line profile at temperatures above 240 K and poorly knownmore » frequencies previously introduced errors into the line shape analyses. Thus, the behavior of the HTP model was compared to the quadratic speed dependent Voigt profile (QSDVP) expressed in the frequency and time domains. A parameter uncertainty analysis was carried out using a Monte Carlo method based on the estimated pressure, transmittance and frequency measurement errors. From the analyses, the P e(11) line strength was estimated to be 1.2014(50) × 10 -20 in cm.molecules⁻¹ units at 296 K with the standard deviation in parenthesis. For analyzing these data, we found that a reduced form of the HTP, equivalent to the QSDVP, was most appropriate because the additional parameters included in the full HTP were not well determined. As a supplement to this work, expressions for analytic derivatives and a lineshape fitting code written in Matlab for the HTP are available.« less

Application of the Hartmann-Tran profile to precise experimental data sets of 12C2H2

NASA Astrophysics Data System (ADS)

Forthomme, D.; Cich, M. J.; Twagirayezu, S.; Hall, G. E.; Sears, T. J.

2015-11-01

Self- and nitrogen-broadened line shape data for the Pe(11) line of the ν1 +ν3 band of acetylene, recorded using a frequency comb-stabilized laser spectrometer, have been analyzed using the Hartmann-Tran profile (HTP) line shape model in a multispectrum fitting. In total, the data included measurements recorded at temperatures between 125 K and 296 K and at pressures between 4 and 760 Torr. New, sub-Doppler, frequency comb-referenced measurements of the positions of multiple underlying hot band lines have also been made. These underlying lines significantly affect the Pe(11) line profile at temperatures above 240 K and poorly known frequencies previously introduced errors into the line shape analyses. The behavior of the HTP model was compared to the quadratic speed dependent Voigt profile (QSDVP) expressed in the frequency and time domains. A parameter uncertainty analysis was carried out using a Monte Carlo method based on the estimated pressure, transmittance and frequency measurement errors. From the analyses, the Pe(11) line strength was estimated to be 1.2014(50) ×10-20 in cmmolecule-1 units at 296 K with the standard deviation in parenthesis. For analyzing these data, we found that a reduced form of the HTP, equivalent to the QSDVP, was most appropriate because the additional parameters included in the full HTP were not well determined. As a supplement to this work, expressions for analytic derivatives and a lineshape fitting code written in Matlab for the HTP are available.

Non-LTE Calculations of the Fe I 6173 Å Line in a Flaring Atmosphere

NASA Astrophysics Data System (ADS)

Hong, Jie; Ding, M. D.; Li, Ying; Carlsson, Mats

2018-04-01

The Fe I 6173 Å line is widely used in the measurements of vector magnetic fields by instruments including the Helioseismic and Magnetic Imager (HMI). We perform non-local thermodynamic equilibrium calculations of this line based on radiative hydrodynamic simulations in a flaring atmosphere. We employ both a quiet-Sun atmosphere and a penumbral atmosphere as the initial one in our simulations. We find that, in the quiet-Sun atmosphere, the line center is obviously enhanced during an intermediate flare. The enhanced emission is contributed from both radiative backwarming in the photosphere and particle beam heating in the lower chromosphere. A blue asymmetry of the line profile also appears due to an upward mass motion in the lower chromosphere. If we take a penumbral atmosphere as the initial atmosphere, the line has a more significant response to the flare heating, showing a central emission and an obvious asymmetry. The low spectral resolution of HMI would indicate some loss of information, but the enhancement and line asymmetry are still kept. By calculating polarized line profiles, we find that the Stokes I and V profiles can be altered as a result of flare heating. Thus the distortion of this line has a crucial influence on the magnetic field measured from this line, and one should be cautious in interpreting the magnetic transients observed frequently in solar flares.

A first-line nurse manager's goal-profile.

PubMed

Johansson, Gunilla; Pörn, Ingmar; Theorell, Töres; Gustafsson, Barbro

2007-01-01

The aim of this case study was to acquire understanding concerning the first-line nurse manager's goal-profile, i.e. prioritization of goals in her work as a first-line nurse manager, through use of an action-theoretic and confirmatory theory. The first-line nurse manager's pivotal role regarding quality of care and development in relation to on-going changes in the health care sector is stressed by many researchers and the transition from nurse to manager is described as a demanding challenge for the first-line nurse manager. The case study described in this paper concerns a first-line nurse manager in an actual working environment in care of older people. Data collection comprised interviews, observations, a job description and policy documents. A hermeneutic interpretation was used for data analysis. The results showed that the first-line nurse manager had three goals in her goal-profile, in the following order of priority: (i) a nurse goal that she had strongly accepted and in which she had excellent control, (ii) an administrator goal that she had accepted and in which she had control, (iii) a leadership goal that she had not accepted and in which she did not have control. Both the administrator and leadership goals were based on her job description, but the nurse goal was a personally chosen goal based on her own self-relation/goal-fulfillment. The first-line nurse manager's prioritized self-identity, based on successful realization of goals in her goal-profile, was decisive in the manifestation of her work. This study contributes to a new understanding of the first-line nurse manager's self-identity related to work in terms of goal acceptance and goal control of prioritized goals. This action-theoretic approach could be a valuable 'key' for understanding leadership (or lack of leadership) in clinical practice.

Bringing the cross-correlation method up to date

NASA Technical Reports Server (NTRS)

Statler, Thomas

1995-01-01

The cross-correlation (XC) method of Tonry & Davis (1979, AJ, 84, 1511) is generalized to arbitrary parametrized line profiles. In the new algorithm the correlation function itself, rather than the observed galaxy spectrum, is fitted by the model line profile: this removes much of the complication in the error analysis caused by template mismatch. Like the Fourier correlation quotient (FCQ) method of Bender (1990, A&A, 229, 441), the inferred line profiles are, up to a normalization constant, independent of template mismatch as long as there are no blended lines. The standard reduced chi(exp 2) is a good measure of the fit of the inferred velocity distribution, largely decoupled from the fit of the spectral template. The updated XC method performs as well as other recently developed methods, with the added virtue of conceptual simplicity.

In situ electrochemical high-energy X-ray diffraction using a capillary working electrode cell geometry

DOE Office of Scientific and Technical Information (OSTI.GOV)

Young, Matthias J.; Bedford, Nicholas M.; Jiang, Naisheng

The ability to generate new electrochemically active materials for energy generation and storage with improved properties will likely be derived from an understanding of atomic-scale structure/function relationships during electrochemical events. Here, the design and implementation of a new capillary electrochemical cell designed specifically forin situhigh-energy X-ray diffraction measurements is described. By increasing the amount of electrochemically active material in the X-ray path while implementing low-Zcell materials with anisotropic scattering profiles, an order of magnitude enhancement in diffracted X-ray signal over traditional cell geometries for multiple electrochemically active materials is demonstrated. This signal improvement is crucial for high-energy X-ray diffraction measurementsmore » and subsequent Fourier transformation into atomic pair distribution functions for atomic-scale structural analysis. As an example, clear structural changes in LiCoO 2under reductive and oxidative conditions using the capillary cell are demonstrated, which agree with prior studies. Accurate modeling of the LiCoO 2diffraction data using reverse Monte Carlo simulations further verifies accurate background subtraction and strong signal from the electrochemically active material, enabled by the capillary working electrode geometry.« less

Time scale variation of MgII resonance lines of HD 41335 in UV region

NASA Astrophysics Data System (ADS)

Nikolaou, I.

2012-01-01

It is known that hot emission stars (Be and Oe) present peculiar and very complex spectral line profiles. Due to these perplexed lines that appear, it is difficult to actually fit a classical distribution to those physical profiles. Therefore many physical parameters of the regions, where these lines are created, can not be determined. In this paper, we study the Ultraviolet (UV) MgII (?? 2795.523, 2802.698 A) resonance lines of the HD 41335 star, at three different periods. Considering that these profiles consist of a number of independent Discrete or Satellite Absorption Components (DACs, SACs), we use the Gauss-Rotation model (GR-model). From this analysis we can estimate the values of a group of physical parameters, such as the apparent rotational and radial velocities, the random velocities of the thermal motions of the ions, as well as the Full Width at Half Maximum (FWHM), the column density and the absorbed energy of the independent regions of matter, which produce the main and the satellite components of the studied spectral lines. Eventually, we calculate the time scale variations of the above physical parameters.

Data set of the protein expression profiles of Luminal A, Claudin-low and overexpressing HER2+ breast cancer cell lines by iTRAQ labelling and tandem mass spectrometry

PubMed Central

Calderón-González, Karla Grisel; Valero Rustarazo, Ma Luz; Labra-Barrios, Maria Luisa; Bazán-Méndez, César Isaac; Tavera-Tapia, Alejandra; Herrera-Aguirre, Marí;aEsther; Sánchez del Pino, Manuel M.; Gallegos-Pérez, José Luis; González-Márquez, Humberto; Hernández-Hernández, Jose Manuel; León-Ávila, Gloria; Rodríguez-Cuevas, Sergio; Guisa-Hohenstein, Fernando; Luna-Arias, Juan Pedro

2015-01-01

Breast cancer is the most common and the leading cause of mortality in women worldwide. There is a dire necessity of the identification of novel molecules useful in diagnosis and prognosis. In this work we determined the differentially expression profiles of four breast cancer cell lines compared to a control cell line. We identified 1020 polypeptides labelled with iTRAQ with more than 95% in confidence. We analysed the common proteins in all breast cancer cell lines through IPA software (IPA core and Biomarkers). In addition, we selected the specific overexpressed and subexpressed proteins of the different molecular classes of breast cancer cell lines, and classified them according to protein class and biological process. Data in this article is related to the research article “Determination of the protein expression profiles of breast cancer cell lines by Quantitative Proteomics using iTRAQ Labelling and Tandem Mass Spectrometry” (Calderón-González et al. [1] in press). PMID:26217805

Observation and modelling of the Fe XXI line profile observed by IRIS during the impulsive phase of flares

NASA Astrophysics Data System (ADS)

Polito, V.; Testa, P.; De Pontieu, B.; Allred, J. C.

2017-12-01

The observation of the high temperature (above 10 MK) Fe XXI 1354.1 A line with the Interface Region Imaging Spectrograph (IRIS) has provided significant insights into the chromospheric evaporation process in flares. In particular, the line is often observed to be completely blueshifted, in contrast to previous observations at lower spatial and spectral resolution, and in agreement with predictions from theoretical models. Interestingly, the line is also observed to be mostly symmetric and with a large excess above the thermal width. One popular interpretation for the excess broadening is given by assuming a superposition of flows from different loop strands. In this work, we perform a statistical analysis of Fe XXI line profiles observed by IRIS during the impulsive phase of flares and compare our results with hydrodynamic simulations of multi-thread flare loops performed with the 1D RADYN code. Our results indicate that the multi-thread models cannot easily reproduce the symmetry of the line and that some other physical process might need to be invoked in order to explain the observed profiles.

Carbon Dioxide Line Shapes for Atmospheric Remote Sensing

NASA Astrophysics Data System (ADS)

Predoi-Cross, Adriana; Ibrahim, Amr; Wismath, Alice; Teillet, Philippe M.; Devi, V. Malathy; Benner, D. Chris; Billinghurst, Brant

2010-02-01

We present a detailed spectroscopic study of carbon dioxide in support of atmospheric remote sensing. We have studied two weak absorption bands near the strong ν2 band that is used to derive atmospheric temperature profiles. We have analyzed our laboratory spectra recorded with the synchrotron and globar sources with spectral line profiles that reproduce the absorption features with high accuracy. The Q-branch transitions exhibited asymmetric line shape due to weak line-mixing. For these weak transitions, we have retrieved accurate experimental line strengths, self- and air-broadening, self- and air-induced shift coefficients and weak line mixing parameters. The experimental precision is sufficient to reveal inherent variations of the width and shift coefficients according to transition quantum numbers.

Voigt spectral profiles in two-photon resonance fluorescence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alexanian, Moorad; Bose, Subir K.; Department of Physics, University of Central Florida, Orlando, Florida 32816

2007-11-15

A recent work on two-photon fluorescence is extended by considering the pump field to be a coherent state, which represents a laser field operating well above threshold. The dynamical conditions are investigated under which the two-photon spectrum gives rise, in addition to a Lorentzian line shape at the pump frequency, to two Voigt spectral sideband profiles. Additional conditions are found under which the Voigt profile behaves like either a Gaussian or a Lorentzian line shape.

System and method for monitoring water content or other dielectric influences in a medium

DOEpatents

Cherry, Robert S.; Anderson, Allen A.

2001-01-01

A sensor system is provided that measures water content or other detectable properties in a medium along the entire length of the sensor at any point in time. The sensor system includes an electromagnetic signal generator and a transmission line disposed in a medium to be monitored. Alternatively, the transmission line can be configured for movement across a medium to be monitored, or the transmission line can be fixed relative to a moving medium being monitored. A signal is transmitted along the transmission line at predetermined frequencies, and the signal is returned back along the transmission line and/or into an optional receive line in proximity to the transmission line. The returned signal is processed to generate a one-dimensional data output profile that is a function of a detectable property of the medium. The data output profile can be mapped onto a physical system to generate a two-dimensional or three-dimensional profile if desired. The sensor system is useful in a variety of different applications such as agriculture, horticulture, biofiltration systems for industrial offgases, leak detection in landfills or drum storage facilities at buried waste sites, and in many other applications.

The influence of microlensing on spectral line shapes generated by a relativistic accretion disc

NASA Astrophysics Data System (ADS)

Popović, L. Č; Mediavilla, E. G.; Muñoz, J. A.

2001-10-01

We study the influence of gravitational microlensing on the spectral line profiles originating from a relativistic accretion disc. Using the Chen & Halpern model for the disc, we show the noticeable changes that microlensing can induce in the line shape when the Einstein radius associated with the microlens is of a size comparable to that of the accretion disc. Of special interest is the relative enhancement between the blue and red peaks of the line when an off-center microlens affects the approaching and receding parts of the accretion disc asymmetrically. In an AGN formed by a super-massive binary in which the accretion disc is located around one of the super-massive companions (the primary), we discuss the possibility of microlensing by the secondary. In this case the ratio between the blue and red peaks of the line profile would depend on the orbital phase. We have also considered the more standard configuration of microlensing by a star-sized object in an intervening galaxy and find that microlensing may also be detected in the broad emission lines of multiply imaged QSOs. The changes observed in the line profile of Arp 102 B are taken as a reference for exploring both scenarios.

Polar POLICRYPS diffractive structures generate cylindrical vector beams

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alj, Domenico; Caputo, Roberto, E-mail: roberto.caputo@fis.unical.it; Umeton, Cesare

2015-11-16

Local shaping of the polarization state of a light beam is appealing for a number of applications. This can be achieved by employing devices containing birefringent materials. In this article, we present one such enables converting a uniformly circularly polarized beam into a cylindrical vector beam (CVB). This device has been fabricated by exploiting the POLICRYPS (POlymer-LIquid CRYstals-Polymer-Slices) photocuring technique. It is a liquid-crystal-based optical diffraction grating featuring polar symmetry of the director alignment. We have characterized the resulting CVB profile and polarization for the cases of left and right circularly polarized incoming beams.

The morphologies of breast cancer cell lines in three-dimensionalassays correlate with their profiles of gene expression

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kenny, Paraic A.; Lee, Genee Y.; Myers, Connie A.

2007-01-31

3D cell cultures are rapidly becoming the method of choice for the physiologically relevant modeling of many aspects of non-malignant and malignant cell behavior ex vivo. Nevertheless, only a limited number of distinct cell types have been evaluated in this assay to date. Here we report the first large scale comparison of the transcriptional profiles and 3D cell culture phenotypes of a substantial panel of human breast cancer cell lines. Each cell line adopts a colony morphology of one of four main classes in 3D culture. These morphologies reflect, at least in part, the underlying gene expression profile and proteinmore » expression patterns of the cell lines, and distinct morphologies were also associated with tumor cell invasiveness and with cell lines originating from metastases. We further demonstrate that consistent differences in genes encoding signal transduction proteins emerge when even tumor cells are cultured in 3D microenvironments.« less

Prevalence and molecular profiles of Salmonella collected at a commercial turkey processing plant.

PubMed

Nde, Chantal W; Sherwood, Julie S; Doetkott, Curt; Logue, Catherine M

2006-08-01

In this study, whole carcasses were sampled at eight stages on a turkey-processing line and Salmonella prevalence was determined using enrichment techniques. Recovered Salmonella was further characterized using serotyping and the molecular profiles were determined using pulsed-field gel electrophoresis (PFGE). Prevalence data showed that contamination rates varied along the line and were greatest after defeathering and after chilling. Analysis of contamination in relation to serotypes and PFGE profiles found that on some visits the same serotype was present all along the processing line while on other days, additional serotypes were recovered that were not detected earlier on the line, suggesting that the birds harbored more than one serotype of Salmonella or there was cross-contamination occurring during processing. Overall, this study found fluctuations in Salmonella prevalence along a turkey-processing line. Following washing, Salmonella prevalence was significantly reduced, suggesting that washing is critical for Salmonella control in turkey processing and has significant application for controlling Salmonella at the postdefeathering and prechill stages where prevalence increased.

High Angular Sensitivity, Absolute Rotary Encoding Device with Polygonal Mirror and Stand-Alone Diffraction Gratings

NASA Technical Reports Server (NTRS)

Leviton, Douglas B. (Inventor)

1996-01-01

A device for position encoding of a rotating shaft in which a polygonal mirror having a number of facets is mounted to the shaft and a monochromatic light beam is directed towards the facets. The facets of the polygonal mirror direct the light beam to a stand-alone low line density diffraction grating to diffract the monochromatic light beam into a number of diffracted light beams such that a number of light spots are created on a linear array detector. An analog-to-digital converter is connected to the linear array detector for reading the position of the spots on the linear array detector means. A microprocessor with memory is connected to the analog-to-digital converter to hold and manipulate the data provided by the analog-to-digital converter on the position of the spots and to compute the position of the shaft based upon the data from the analog-lo-digital converter.

Crystal-Site-Selective Spectrum of Fe3BO6 by Synchrotron Mössbauer Diffraction with Pure Nuclear Bragg Scattering

NASA Astrophysics Data System (ADS)

Nakamura, Shin; Mitsui, Takaya; Fujiwara, Kosuke; Ikeda, Naoshi; Kurokuzu, Masayuki; Shimomura, Susumu

2017-08-01

We have succeeded in obtaining the crystal-site-selective spectra of the collinear antiferromagnet Fe3BO6 using a synchrotron Mössbauer diffractometer with pure nuclear Bragg scattering at SPring-8 BL11XU. Well-resolved 300, 500, and 700 reflection spectra, having asymmetric line shapes owing to the higher-order interference effect between the nuclear energy levels, were quantitatively analyzed using a formula based on the dynamical theory of diffraction. Reasonable hyperfine parameters were obtained. The intensity ratio of Fe1 to Fe2 subspectra is in accordance with the nuclear structure factor. However, when the spectrum is measured at the peak position of the rocking curve (very near the Bragg position), the value of the center shift deviates from its intrinsic value. This is also due to the dynamical effect of γ-ray diffraction. To avoid this problem, it is necessary to use diffraction angles near the foot of the rocking curve, approximately 0.02° apart from the peak position.

Characterization of high energy Xe ion irradiation effects in single crystal molybdenum with depth-resolved synchrotron microbeam diffraction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yun, Di; Miao, Yinbin; Xu, Ruqing

2016-04-01

Microbeam X-ray diffraction experiments were conducted at beam line 34-ID of the Advanced Photon Source (APS) on fission fragment energy Xe heavy ion irradiated single crystal Molybdenum (Mo). Lattice strain measurements were obtained with a depth resolution of 0.7 mu m, which is critical in resolving the peculiar heterogeneity of irradiation damage associated with heavy ion irradiation. Q-space diffraction peak shift measurements were correlated with lattice strain induced by the ion irradiations. Transmission electron microscopy (TEM) characterizations were performed on the as-irradiated materials as well. Nanometer sized Xe bubble microstructures were observed via TEM. Molecular Dynamics (MD) simulations were performedmore » to help interpret the lattice strain measurement results from the experiment. This study showed that the irradiation effects by fission fragment energy Xe ion irradiations can be collaboratively understood with the depth resolved X-ray diffraction and TEM measurements under the assistance of MD simulations. (c) 2015 Elsevier B.V. All rights reserved.« less

Coronal Structures in Cool Stars

NASA Technical Reports Server (NTRS)

Oliversen, Ronald (Technical Monitor); Dupree, Andrea K.

2004-01-01

Many papers have been published that further elucidate the structure of coronas in cool stars as determined from EUVE, HST, FUSE, Chandra, and XMM-Newton observations. In addition we are exploring the effects of coronas on the He I 1083081 transition that is observed in the infrared. Highlights of these are summarized below including publications during this reporting period and presentations. Ground-based magnetic Doppler imaging of cool stars suggests that active stars have active regions located at high latitudes on their surface. We have performed similar imaging in X-ray to locate the sites of enhanced activity using Chandra spectra. Chandra HETG observations of the bright eclipsing contact binary 44i Boo and Chandra LETG observations for the eclipsing binary VW Cep show X-ray line profiles that are Doppler-shifted by orbital motion. After careful analysis of the spectrum of each binary, a composite line-profile is constructed by adding the individual spectral lines. This high signal-to-noise ratio composite line-profile yields orbital velocities for these binaries that are accurate to 30 km/sec and allows their orbital motion to be studied at higher time resolutions. In conjunction with X-ray lightcurves, the phase-binned composite line-profiles constrain coronal structures to be small and located at high latitudes. These observations and techniques show the power of the Doppler Imaging Technique applied to X-ray line emission.

Be Star Hα Line Profile Variability

NASA Astrophysics Data System (ADS)

Austin, S. J.; Dunlap, B.; Franklin, M.; Hoggard, T.; Hoskins, J. S.

2004-12-01

The monitoring of the spectroscopic variability of Be stars is crucial for testing Be star models. Motivated by this, a Be star monitoring project was developed for undergraduate student research involvement. We have been obtaining 0.8 Angstrom/pixel resolution Hα line profiles for several bright Be stars since 2003 June. These spectra were acquired using the UCA Fiber Fed Spectrograph used at the UCA Observatory and the Nubbin Ridge Observatory in Royal, AR. H-α line profiles, velocities, and variability are shown for Delta Sco, Chi Oph, Eta PsA, 48 Lib, and Upsilon Sgr (HD181615). Funding has been provided by the UCA University Research Council and the Arkansas Space Grant Consortium.

Wall-collision line broadening of molecular oxygen within nanoporous materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xu, Can T.; Lewander, Maerta; Andersson-Engels, Stefan

2011-10-15

Wall-collision broadening of near-infrared absorption lines of molecular oxygen confined in nanoporous zirconia is studied by employing high-resolution diode-laser spectroscopy. The broadening is studied for pores of different sizes under a range of pressures, providing new insights on how wall collisions and intermolecular collisions influence the total spectroscopic line profile. The pressure series show that wall-collision broadening is relatively more prominent under reduced pressures, enabling sensitive means to probe pore sizes of porous materials. In addition, we show that the total wall-collision-broadened profile strongly deviates from a Voigt profile and that wall-collision broadening exhibits an additive-like behavior to the pressuremore » and Doppler broadening.« less

Optical track width measurements below 100 nm using artificial neural networks

NASA Astrophysics Data System (ADS)

Smith, R. J.; See, C. W.; Somekh, M. G.; Yacoot, A.; Choi, E.

2005-12-01

This paper discusses the feasibility of using artificial neural networks (ANNs), together with a high precision scanning optical profiler, to measure very fine track widths that are considerably below the conventional diffraction limit of a conventional optical microscope. The ANN is trained using optical profiles obtained from tracks of known widths, the network is then assessed by applying it to test profiles. The optical profiler is an ultra-stable common path scanning interferometer, which provides extremely precise surface measurements. Preliminary results, obtained with a 0.3 NA objective lens and a laser wavelength of 633 nm, show that the system is capable of measuring a 50 nm track width, with a standard deviation less than 4 nm.

Non-stationary self-focusing of intense laser beam in plasma using ramp density profile

DOE Office of Scientific and Technical Information (OSTI.GOV)

Habibi, M.; Ghamari, F.

2011-10-15

The non-stationary self-focusing of high intense laser beam in under-dense plasma with upward increasing density ramp is investigated. The obtained results show that slowly increasing plasma density ramp is very important in enhancing laser self-focusing. Also, the spot size oscillations of laser beam in front and rear of the pulse for two different density profiles are shown. We have selected density profiles that already were used by Sadighi-Bonabi et al.[Phys. Plasmas 16, 083105 (2009)]. Ramp density profile causes the laser beam to become more focused and penetrations deeps into the plasma by reduction of diffraction effects. Our computations show moremore » reliable results in comparison to the previous works.« less

Pulse generation and preamplification for long pulse beamlines of Orion laser facility.

PubMed

Hillier, David I; Winter, David N; Hopps, Nicholas W

2010-06-01

We describe the pulse generation, shaping, and preamplification system for the nanosecond beamlines of the Orion laser facility. The system generates shaped laser pulses of up to approximately 1 J of 100 ps-5 ns duration with a programmable temporal profile. The laser has a 30th-power supergaussian spatial profile and is diffraction limited. The system is capable of imposing 2D smoothing by spectral dispersion upon the beam, which will produce a nonuniformity of 10% rms at the target.

Relativistically Skewed Iron Emission and Disk Reflection in Galactic Microquasar XTE J1748-288

NASA Technical Reports Server (NTRS)

Miller, J. M.; Fox, D. W.; DiMatteo, T.; Wijnands, R.; Belloni, T.; Kouveliotou, C.; Lewin, W. H. G.

2000-01-01

We report evidence for an Fe K-alpha fluorescence line feature in the Very High, High, and Low state X-ray spectra of the galactic microquasar XTE JI748-288 during its June 1998 outburst. Spectral analyses were made on observations spread across the outburst, gathered with the Rossi X-ray Timing Explorer. Gaussian line. disk emission line, relativistic disk emission line, and disk reflection models are fit to the data. In the Very High State, the line profile is strongly redshifted and consistent with emission from the innermost radius of a maximally rotating Kerr black hole, 1.235 R(sub g). The line profile is less redshifted in the High State, but increasingly prominent. In the Low State, the line profile is very strong and centered af approx. 6.7 keV; disk line emission models constrain the inner edge of the disk to fluctuate between approx.20 and approx.59 R(sub g). We trace the disk reflection fraction across the full outburst of this source, and find well-constrained fractions below those observed in AGN in the Very High and High States, but consistent with other galactic sources in the Low State. We discuss the possible implications for black hole X-ray binary system dynamics and accretion flow geometry.

The effect of buildings on acoustic pulse propagation in an urban environment.

PubMed

Albert, Donald G; Liu, Lanbo

2010-03-01

Experimental measurements were conducted using acoustic pulse sources in a full-scale artificial village to investigate the reverberation, scattering, and diffraction produced as acoustic waves interact with buildings. These measurements show that a simple acoustic source pulse is transformed into a complex signature when propagating through this environment, and that diffraction acts as a low-pass filter on the acoustic pulse. Sensors located in non-line-of-sight (NLOS) positions usually recorded lower positive pressure maxima than sensors in line-of-sight positions. Often, the first arrival on a NLOS sensor located around a corner was not the largest arrival, as later reflection arrivals that traveled longer distances without diffraction had higher amplitudes. The waveforms are of such complexity that human listeners have difficulty identifying replays of the signatures generated by a single pulse, and the usual methods of source location based on the direction of arrivals may fail in many cases. Theoretical calculations were performed using a two-dimensional finite difference time domain (FDTD) method and compared to the measurements. The predicted peak positive pressure agreed well with the measured amplitudes for all but two sensor locations directly behind buildings, where the omission of rooftop ray paths caused the discrepancy. The FDTD method also produced good agreement with many of the measured waveform characteristics.

Interstellar lines in high resolution IUE spectra. Part 1: Groningen data reduction package and technical results

NASA Astrophysics Data System (ADS)

Gilra, D. P.; Pwa, T. H.; Arnal, E. M.; de Vries, J.

1982-06-01

In order to process and analyze high resolution IUE data on a large number of interstellar lines in a large number of images for a large number of stars, computer programs were developed for 115 lines in the short wavelength range and 40 in the long wavelength range. Programs include extraction, processing, plotting, averaging, and profile fitting. Wavelength calibration in high resolution spectra, fixed pattern noise, instrument profile and resolution, and the background problem in the region where orders are crowding are discussed. All the expected lines are detected in at least one spectrum.

Discrete diffraction managed solitons: Threshold phenomena and rapid decay for general nonlinearities

NASA Astrophysics Data System (ADS)

Choi, Mi-Ran; Hundertmark, Dirk; Lee, Young-Ran

2017-10-01

We prove a threshold phenomenon for the existence/non-existence of energy minimizing solitary solutions of the diffraction management equation for strictly positive and zero average diffraction. Our methods allow for a large class of nonlinearities; they are, for example, allowed to change sign, and the weakest possible condition, it only has to be locally integrable, on the local diffraction profile. The solutions are found as minimizers of a nonlinear and nonlocal variational problem which is translation invariant. There exists a critical threshold λcr such that minimizers for this variational problem exist if their power is bigger than λcr and no minimizers exist with power less than the critical threshold. We also give simple criteria for the finiteness and strict positivity of the critical threshold. Our proof of existence of minimizers is rather direct and avoids the use of Lions' concentration compactness argument. Furthermore, we give precise quantitative lower bounds on the exponential decay rate of the diffraction management solitons, which confirm the physical heuristic prediction for the asymptotic decay rate. Moreover, for ground state solutions, these bounds give a quantitative lower bound for the divergence of the exponential decay rate in the limit of vanishing average diffraction. For zero average diffraction, we prove quantitative bounds which show that the solitons decay much faster than exponentially. Our results considerably extend and strengthen the results of Hundertmark and Lee [J. Nonlinear Sci. 22, 1-38 (2012) and Commun. Math. Phys. 309(1), 1-21 (2012)].

Geocoronal structure. 3. Optically thin, Doppler-broadened line profiles

NASA Astrophysics Data System (ADS)

Bishop, James; Chamberlain, Joseph W.

1987-11-01

Theoretical line profiles, applicable to the analysis of geocoronal Hα prifile measurements, are presented for illustrative cases. While retaining a number of simplifications (classical exobase and diffusive equilibrium plasmasphere conditions), distinctive spectral signatures of mechanisms governing the geocorona are isolated. Examining the consequences of solar radiation pressure dynamics is the main point here. In the prototype evaporative case, radiation pressure acts to form narrow profiles via the creation of an extensive quasi-satellite component. Comparison with a simple extension of the earlier analytic theory discloses the influence of an exopause in this regard. The main modifications to evaporative spectral shapes in the geocoronal application, for shadow heights greater than 2 RE, are predicted to be (1) a blueward ``shift'' or bias near line center, for look directions parallel to the antisolar axis, generated by loss mechanisms acting over the time of flight of exospheric constituents (for example, solar ionization) and (2) an enhanced redward wing at spectral displacements exceeding that defined by the shadow height escape speed, produced by plasmaspheric charge exchange collisions. Implications of these results for recent observations of geocoronal Hα line profiles are briefly discussed.

Proposed rocket experiments to measure the profile and intensity of the solar He1584A resonance line

NASA Technical Reports Server (NTRS)

Judge, D. L.

1978-01-01

The intensity and profile of the helium resonance line at 584 A from the entire disc of the sun was investigated using a rocket-borne helium-filled spectrometer and a curve of growth technique. The line profile was found to be accurately represented by a Gaussian profile with full width at half maximum of 122 plus or minus 10m A while the integrated intensity was measured to be (2.6 plus or minus 1.3) x 10 to the 9th power/photons sec sq cm at solar levels of F sub 10.7 = 90.8 x 10 to the minus 22th power/sq m H sub z and R sub z = 27. The measured linewidth is in good agreement with previous spectrographic measurement but the integrated intensity is larger than most previous photoelectric measurements. However, the derived line center flux of (2.0 plus or minus 1.0) x 10 to the 10th power/photons sec sq cm A is in good agreement with values inferred from airglow measurements.

New Insights into the Puzzling P-Cygni Profiles of Magnetic Massive Stars

NASA Astrophysics Data System (ADS)

Erba, Christiana; David-Uraz, Alexandre; Petit, Véronique; Owocki, Stanley P.

2017-11-01

Magnetic massive stars comprise approximately 10% of the total OB star population. Modern spectropolarimetry shows these stars host strong, stable, large-scale, often nearly dipolar surface magnetic fields of 1 kG or more. These global magnetic fields trap and deflect outflowing stellar wind material, forming an anisotropic magnetosphere that can be probed with wind-sensitive UV resonance lines. Recent HST UV spectra of NGC 1624-2, the most magnetic O star observed to date, show atypically unsaturated P-Cygni profiles in the Civ resonant doublet, as well as a distinct variation with rotational phase. We examine the effect of non-radial, magnetically-channeled wind outflow on P-Cygni line formation, using a Sobolev Exact Integration (SEI) approach for direct comparison with HST UV spectra of NGC 1624-2. We demonstrate that the addition of a magnetic field desaturates the absorption trough of the P-Cygni profiles, but further efforts are needed to fully account for the observed line profile variation. Our study thus provides a first step toward a broader understanding of how strong magnetic fields affect mass loss diagnostics from UV lines.

Profile parameters of wheelset detection for high speed freight train

NASA Astrophysics Data System (ADS)

Yang, Kai; Ma, Li; Gao, Xiaorong; Wang, Li

2012-04-01

Because of freight train, in China, transports goods on railway freight line throughout the country, it does not depart from or return to engine shed during a long phase, thus we cannot monitor the quality of wheel set effectively. This paper provides a system which uses leaser and high speed camera, applies no-contact light section technology to get precise wheel set profile parameters. The paper employs clamping-track method to avoid complex railway ballast modification project. And detailed descript an improved image-tracking algorithm to extract central line from profile curve. For getting one pixel width and continuous line of the profile curve, uses local gray maximum points as direction control points to direct tracking direction. The results based on practical experiment show the system adapted to detection environment of high speed and high vibration, and it can effectively detect the wheelset geometric parameters with high accuracy. The system fills the gaps in wheel set detection for freight train in main line and has an enlightening function on monitoring the quality of wheel set.

Observations of chromospheric lines from OSO-8

NASA Technical Reports Server (NTRS)

Grossmann-Doerth, U.; Kneer, F.; Uexkuell, M.; Artzner, G. E.; Vial, J. C.

1980-01-01

Results of OSO-8 measurements of the line profiles of the solar Lyman alpha, Ca II K and Mg II k lines are presented. Observations were obtained with the Laboratoire de Physique Stellaire et Planetaire spectrometer at spectral resolutions of 0.25 and 0.060 A for Lyman alpha and 0.025 A for the Mg II and Ca II lines. The Lyman alpha profiles are found to be highly variable according to spatial position with the intensities of the three lines well correlated, and confirm previous observations of the quiet solar chromosphere. Data suggest that the quiet chromosphere is a dynamical phenomenon whose description in terms of a static model atmosphere is only qualitatively valid at best.

High-performance axicon lenses based on high-contrast, multilayer gratings

NASA Astrophysics Data System (ADS)

Doshay, Sage; Sell, David; Yang, Jianji; Yang, Rui; Fan, Jonathan A.

2018-01-01

Axicon lenses are versatile optical elements that can convert Gaussian beams to Bessel-like beams. In this letter, we demonstrate that axicons operating with high efficiencies and at large angles can be produced using high-contrast, multilayer gratings made from silicon. Efficient beam deflection of incident monochromatic light is enabled by higher-order optical modes in the silicon structure. Compared to diffractive devices made from low-contrast materials such as silicon dioxide, our multilayer devices have a relatively low spatial profile, reducing shadowing effects and enabling high efficiencies at large deflection angles. In addition, the feature sizes of these structures are relatively large, making the fabrication of near-infrared devices accessible with conventional optical lithography. Experimental lenses with deflection angles as large as 40° display field profiles that agree well with theory. Our concept can be used to design optical elements that produce higher-order Bessel-like beams, and the combination of high-contrast materials with multilayer architectures will more generally enable new classes of diffractive photonic structures.

Large-area uniform periodic microstructures on fused silica induced by surface phonon polaritons and incident laser

NASA Astrophysics Data System (ADS)

Zhang, Chuanchao; Liao, Wei; Zhang, Lijuan; Jiang, Xiaolong; Chen, Jing; Wang, Haijun; Luan, Xiaoyu; Yuan, Xiaodong

2018-06-01

A simple and convenient means to self-organize large-area uniform periodic microstructures on fused silica by using multiple raster scans of microsecond CO2 laser pulses with beam spot overlapping at normal incidence is presented, which is based on laser-induced periodic surface structures (LIPSS) attributed to the interference between surface phonon polaritons and incident CO2 laser. The evolution of fused silica surface morphologies with increasing raster scans indicates that the period of microstructures changed from 10.6 μm to 9 μm and the profiles of microstructures changed from a sinusoidal curve to a half-sinusoidal shape. Numerical simulation results suggest that the formation of the half-sinusoidal profile is due to the exponential relationship between evaporation rate and surface temperature inducing by the intensive interference between surface phonon polaritons and incident laser. The fabricated uniform periodic microstructures show excellent structural color effect in both forward-diffraction and back-diffraction.

Calculation of effective penetration depth in X-ray diffraction for pharmaceutical solids.

PubMed

Liu, Jodi; Saw, Robert E; Kiang, Y-H

2010-09-01

The use of the glancing incidence X-ray diffraction configuration to depth profile surface phase transformations is of interest to pharmaceutical scientists. The Parratt equation has been used to depth profile phase changes in pharmaceutical compacts. However, it was derived to calculate 1/e penetration at glancing incident angles slightly below the critical angle of condensed matter and is, therefore, applicable to surface studies of materials such as single crystalline nanorods and metal thin films. When the depth of interest is 50-200 microm into the surface, which is typical for pharmaceutical solids, the 1/e penetration depth, or skin depth, can be directly calculated from an exponential absorption law without utilizing the Parratt equation. In this work, we developed a more relevant method to define X-ray penetration depth based on the signal detection limits of the X-ray diffractometer. Our definition of effective penetration depth was empirically verified using bilayer compacts of varying known thicknesses of mannitol and lactose.

QSO Broad Emission Line Asymmetries: Evidence of Gravitational Redshift?

NASA Astrophysics Data System (ADS)

Corbin, Michael R.

1995-07-01

The broad optical and ultraviolet emission lines of QSOs and active galactic nuclei (AGNs) display both redward and blueward asymmetries. This result is particularly well established for Hβ and C IV λ1549, and it has been found that Hβ becomes increasingly redward asymmetric with increasing soft X-ray luminosity. Two models for the origin of these asymmetries are investigated: (1) Anisotropic line emission from an ensemble of radially moving clouds, and (2) Two-component profiles consisting of a core of intermediate (˜1000-4000 km s-1) velocity width and a very broad (˜5000-20,000 km s-1) base, in which the asymmetries arise due to a velocity difference between the centroids of the components. The second model is motivated by the evidence that the traditional broad-line region is actually composed of an intermediate-line region (ILR) of optically thick clouds and a very broad line region (VBLR) of optically thin clouds lying closer to the central continuum source. Line profiles produced by model (1) are found to be inconsistent with those observed, being asymmetric mainly in their cores, whereas the asymmetries of actual profiles arise mainly from excess emission in their wings. By contrast, numerical fitting to actual Hβ and C IV λ1549 line profiles reveals that the majority can be accurately modeled by two components, either two Gaussians or the combination of a Gaussian base and a logarithmic core. The profile asymmetries in Hβ can be interpreted as arising from a shift of the base component over a range ˜6300 km s-1 relative to systemic velocity as defined by the position of the [O III] λ5007 line. A similar model appears to apply to C IV λ1549. The correlation between Hβ asymmetry and X-ray luminosity may thus be interpreted as a progressive red- shift of the VBLR velocity centroid relative to systemic velocity with increasing X-ray luminosity. This in turn suggests that the underlying effect is gravitational red shift, as soft X-ray emission arises from a region ˜ light-minutes in size and arguably traces the mass of the putative supermassive black hole. Depending on the size of the VBLR and the exact amount of its profile centroid shift, central masses in the range 109-10 Msun are implied for the objects displaying the strongest redward profile asymmetries, consistent with other estimates. The largest VBLR velocity dispersions measured from the two-component modeling are ˜20,000 km s-1, which also yields a virial mass ˜109 Msun for a VBLR size 0.1 pc. The gravitational redshift model does not explain the origin of the blueshift of the VBLR emission among low X-ray luminosity sources, however. This must be interpreted as arising from a competing effect such as electron scattering of line photons in the vicinity of the VBLR. On average, radio-loud objects have redward asymmetric broad-line profiles and stronger intermediate- and narrow-line emission than radio-quiet objects of comparable optical luminosity. Under the gravitational redshift model these differences may be interpreted as the result of black hole and host galaxy masses that are larger on average among the former class, consistent with the evidence that they are merger products.

Atomic Oscillator Strengths in the Vacuum Ultraviolet

NASA Technical Reports Server (NTRS)

Nave, Gillian; Sansonetti, Craig J.; Szabo, Csilla I.

2006-01-01

We have developed techniques to measure branching fractions in the vacuum ultraviolet using diffraction grating spectroscopy and phosphor image plates as detectors. These techniques have been used to measure branching fractions in Fe II that give prominent emission lines in astrophysical objects.

In vivo synthesis of selenium nanoparticles by Halococcus salifodinae BK18 and their anti-proliferative properties against HeLa cell line.

PubMed

Srivastava, Pallavee; Braganca, Judith M; Kowshik, Meenal

2014-01-01

Nanoparticles synthesis by bacteria and yeasts has been widely reported, however, synthesis using halophilic archaea is still in a nascent stage. This study aimed at the intracellular synthesis of selenium nanoparticles (SeNPs) by the haloarchaeon Halococcus salifodinae BK18 when grown in the presence of sodium selenite. Crystallographic characterization of SeNPs by X-ray diffraction, Selected area electron diffraction, and transmission electron microscopy exhibited rod shaped nanoparticles with hexagonal crystal lattice, a crystallite domain size of 28 nm and an aspect ratio (length:diameter) of 13:1. Energy disruptive analysis of X-ray analysis confirmed the presence of selenium in the nano-preparation. The nitrate reductase enzyme assay and the inhibitor studies indicated the involvement of NADH-dependent nitrate reductase in SeNPs synthesis and metal tolerance. The SeNPs exhibited good anti-proliferative properties against HeLa cell lines while being non-cytotoxic to normal cell line model HaCat, suggesting the use of these SeNPs as cancer chemotherapeutic agent. This is the first study on selenium nanoparticles synthesis by haloarchaea. © 2014 American Institute of Chemical Engineers.

Iron K lines from low-mass X-ray binaries

NASA Technical Reports Server (NTRS)

Kallman, T.; White, N. E.

1989-01-01

Models are presented for the 6-7 keV iron line emission from low-mass X-ray binaries. A simplified model for an accretion disk corona is used to examine the dependence of the observable line properties, line width and mean energy, on the radial distance of the emission region from the X-ray source, and on the fraction of the X-rays from the source which reach the disk surface. The effects of blending of multiple line components and of Comptonization of the line profile are included in numerical calculations of the emitted profile shape. The results of these calculations, when compared with the line properties observed from several low-mass X-ray binaries, suggest that the broadening is dominated either by rotation or by Compton scattering through a greater optical depth than is expected from an accretion disk corona.

Broad Redshifted Line as a Signature of Outflow

NASA Astrophysics Data System (ADS)

Titarchuk, Lev; Kazanas, Demos; Becker, Peter A.

2003-11-01

We formulate and solve the diffusion problem of line photon propagation in a bulk outflow from a compact object (black hole or neutron star) using a generic assumption regarding the distribution of line photons within the outflow. Thomson scattering of the line photons within the expanding flow leads to a decrease of their energy which is of first order in v/c, where v is the outflow velocity and c is the speed of light. We demonstrate that the emergent line profile is closely related to the time distribution of photons diffusing through the flow (the light curve) and consists of a broad redshifted feature. We analyzed the line profiles for the general case of outflow density distribution. We emphasize that the redshifted lines are intrinsic properties of the powerful outflow that are supposed to be in many compact objects.

Broad Red-Shifted Lines as a Signature of Outflow

NASA Astrophysics Data System (ADS)

Kazanas, Demosthenes; Titarchuk, Lev; Becker, Peter A.

2004-07-01

We formulate and solve the diffusion problem of line photon propagation in a bulk outflow from a compact object (black hole or neutron star) using a generic assumption regarding the distribution of line photons within the outflow. Thomson scattering of the line photons within the expanding flow leads to a decrease of their energy which is of first order in v/c, where v is the outflow velocity and c the speed of light. We demonstrate that the emergent line profile is closely related to the time distribution of photons diffusing through the flow (the light curve) and consists of a broad redshifted feature. We analyzed the line profiles for the general case of outflow density distribution. We emphasize that the redshifted lines are intrinsic properties of the powerful outflow that are supposed to be in many compact objects.

Broad Red-Shifted Lines as a Signature of Outflows

NASA Astrophysics Data System (ADS)

Titarchuck, Lev; Kazanas, Demos; Becker, Peter A.

2006-02-01

We formulate and solve the diffusion problem of line photon propagation in a bulk outflow from a compact object (black hole or neutron star) using a generic assumption regarding the distribution of line photons within the outflow. Thomson scattering of the line photons within the expanding flow leads to a decrease of their energy which is of first order in υ/c, where υ the outflow velocity and c is the speed of light. We demonstrate that the emergent line profile is closely related to the time distribution of photons diffusing through the flow (the light curve) and consists of a broad redshifted feature. We analyzed the line profiles for the general case of outflow density distribution. We emphasize that the redshifted lines are intrinsic properties of the powerful outflow that are supposed to be in many compact objects.

Line profile variation in delta-Orionis A, l-Orionis A, and 15 Monocerotis

NASA Technical Reports Server (NTRS)

Grady, C. A.; Snow, T. P.; Cash, W. C.

1984-01-01

The results of a monitoring program with IUE and Einstein are presented for three stars, delta-Ori A, l-Ori A, and 15 Mon. Line profile variability is observed in the UV profiles accessible to IUE and the relation between the variation in the different ions suggests that the ionization level is varying in the winds of these stars. This is consistent with Einstein observations of soft X-ray variability for two of the stars.

Differential absorption lidar measurements of atmospheric temperature and pressure profiles

NASA Technical Reports Server (NTRS)

Korb, C. L.

1981-01-01

The theory and methodology of using differential absorption lidar techniques for the remote measurement of atmospheric pressure profiles, surface pressure, and temperature profiles from ground, air, and space-based platforms are presented. Pressure measurements are effected by means of high resolution measurement of absorption at the edges of the oxygen A band lines where absorption is pressure dependent due to collisional line broadening. Temperature is assessed using measurements of the absorption at the center of the oxygen A band line originating from a quantum state with high ground state energy. The population of the state is temperature dependent, allowing determination of the temperature through the Boltzmann term. The results of simulations of the techniques using Voigt profile and variational analysis are reported for ground-based, airborne, and Shuttle-based systems. Accuracies in the 0.5-1.0 K and 0.1-0.3% range are projected.

Spectral Variability of the Herbig Ae/Be Star HD 37806

NASA Astrophysics Data System (ADS)

Pogodin, M. A.; Pavlovskiy, S. E.; Kozlova, O. V.; Beskrovnaya, N. G.; Alekseev, I. Yu.; Valyavin, G. G.

2018-03-01

Results are reported from a spectroscopic study of the Herbig Ae/Be star HD 37806 from 2009 through 2017 using high resolution spectrographs at the Crimean Astrophysical Observatory and the OAN SPM Observatory in Mexico. 72 spectra of this object near the Hα, Hβ, HeI 5876 and D NaI lines are analyzed. The following results were obtained: 1. The type of spectral profile of the Hα line can change from P Cyg III to double emission and vice versa over a time scale on the order of a month. 2. Narrow absorption components are observed in the profiles of the Hα and D NaI lines with radial velocities that vary over a characteristic time on the order of a day. 3. On some days, the profiles of the Hβ, HeI 5876, and D NaI lines show signs of accretion of matter to the star with a characteristic lifetime of a few days. A possible interpretation of these phenomena was considered. The transformation of the Hα profile may be related to a change in the outer latitudinal width of the boundary of the wind zone. The narrow variable absorption lines may be caused by the rotation of local azimuthal inhomogeneities in the wind zone owing to the interaction of the disk with the star's magnetosphere in a propeller regime. Several current theoretical papers that predict the formation of similar inhomogeneous wind structures were examined. It is suggested that the episodes with signs of accretion in the spectral line profiles cannot be a consequence of the modulation of these profiles by the star's rotation but are more likely caused by sudden, brief changes in the accretion rate. These spectral observations of HD 37806 should be continued in a search for cyclical variability in the spectral parameters in order to identify direct signs of magnetospheric accretion and detect possible binary behavior in this object.

Mars Ozone Absorption Line Shapes from Infrared Heterodyne Spectra Applied to GCM-Predicted Ozone Profiles and to MEX/SPICAM Column Retrievals

NASA Technical Reports Server (NTRS)

Fast, Kelly E.; Kostiuk, T.; Annen, J.; Hewagama, T.; Delgado, J.; Livengood, T. A.; Lefevre, F.

2008-01-01

We present the application of infrared heterodyne line shapes of ozone on Mars to those produced by radiative transfer modeling of ozone profiles predicted by general circulation models (GCM), and to contemporaneous column abundances measured by Mars Express SPICAM. Ozone is an important tracer of photochemistry Mars' atmosphere, serving as an observable with which to test predictions of photochemistry-coupled GCMs. Infrared heterodyne spectroscopy at 9.5 microns with spectral resolving power >1,000,000 is the only technique that can directly measure fully-resolved line shapes of Martian ozone features from the surface of the Earth. Measurements were made with Goddard Space Flight Center's Heterodyne instrument for Planetary Wind And Composition (HIPWAC) at the NASA Infrared Telescope Facility (IRTF) on Mauna Kea, Hawaii on February 21-24 2008 UT at Ls=35deg on or near the MEX orbital path. The HIPWAC observations were used to test GCM predictions. For example, a GCM-generated ozone profile for 60degN 112degW was scaled so that a radiative transfer calculation of its absorption line shape matched an observed HIPWAC absorption feature at the same areographic position, local time, and season. The RMS deviation of the model from the data was slightly smaller for the GCM-generated profile than for a line shape produced by a constant-with-height profile, even though the total column abundances were the same, showing potential for testing and constraining GCM ozone-profiles. The resulting ozone column abundance from matching the model to the HIPWAC line shape was 60% higher than that observed by SPICAM at the same areographic position one day earlier and 2.5 hours earlier in local time. This could be due to day-to-day, diurnal, or north polar region variability, or to measurement sensitivity to the ozone column and its distribution, and these possibilities will be explored. This work was supported by NASA's Planetary Astronomy Program.

Influence of the Doppler effect on radiative transfer in a spherical plasma under macroscopic motion of substance

NASA Astrophysics Data System (ADS)

Kosarev, N. I.

2018-03-01

The non-LTE radiative transfer in spherical plasma containing resonantly absorbing light ions has been studied numerically under conditions of macroscopic motion of substance. Two types of macroscopic motion were simulated: radial expansion and compression (pulsation) of spherical plasma; rotation of plasma relative to an axis of symmetry. The calculations of absorption line profile of transmitted broadband radiation and the emission line profile were performed for the optically dense plasma of calcium ions on the resonance transition with wavelength 397 nm. Numerical results predict frequency shifts in the emission line profile to red wing of the spectrum for radial expansion of the plasma and to blue wing of the spectrum for the plasma compression at an average velocity of ions along the ray of sight equal to zero. The width of the emission line profile of a rotating plasma considerably exceeds the width of the profile of the static plasma, and the shift of the central frequency of resonance transition from the resonance frequency of the static plasma gives a linear velocity of ion motion along a given ray trajectory in units of thermal velocity. Knowledge of the linear radial velocity of ions can be useful for diagnostic purposes in determining the frequency and period of rotation of optically dense plasmas.

An atlas of Copernicus ultraviolet spectra of Wolf-Rayet stars

NASA Technical Reports Server (NTRS)

Johnson, H. M.

1978-01-01

An atlas of Copernicus UV scans is presented, and line identifications are tabulated, for the Wolf-Rayet stars Gamma-2 Vel (WC 8 + O7), HD 50896 (= EZ CMa; WN 5), and HD 92740 (WN 7). The atlas covers the wavelength ranges from 946.8 to 3182 A for Gamma-2 Vel, from 1012 to 1294 A for HD 50896, and from 1051 to 1243 A for HD 92740. The wavelengths include corrections for components of satellite velocity, earth velocity, and stellar heliocentric velocity; each spectral feature is classified as interstellar, photospheric, emission, UV-displaced P Cygni line absorption, or P Cygni line emission. UV-edge velocities of the P Cygni profiles are estimated, P Cygni profile types are discussed, and the results are compared with Copernicus scans of OB stars exhibiting UV P Cygni profiles. It is noted that: (1) the line-strength ratio of molecular hydrogen to atomic species appears to be substantially greater in the scans of the WN stars than in the Gamma-2 Vel scans; (2) some of the P Cygni profiles in Gamma-2 Vel differ significantly from the corresponding profiles in OB stars; and (3) there may be a slight inverse correlation between ejection velocities and excitation potentials in Gamma-2 Vel.

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

NASA Technical Reports Server (NTRS)

Rodrigues, Liliya L.; Boehm-Vitense, Erika

1990-01-01

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

Line Profile of H Lyman (alpha) from Dissociative Excitation of H2 with Application to Jupiter

NASA Technical Reports Server (NTRS)

Ajello, Joseph M.; Kasnik, Isik; Ahmed, Syed M.; Clarke, John T.

1995-01-01

Observations of the H Lyman(alpha) (Ly-alpha) emission from Jupiter have shown pronounced emissions, exceeding solar fluorescence, in the polar aurora and equatorial "bulge" regions. The H Ly-alpha line profiles from these regions are broader than expected, indicating high-energy processes producing fast atoms as determined from the observed Doppler broadening. Toward understanding that process a high-resolution ultraviolet (UV) spectrometer was employed for the first measurement of the H Ly-alpha emission Doppler profile from dissociative excitation of H2 by electron impact. Analysis of the deconvolved line profile reveals the existence of a narrow central peak of 40 +/- 4 mA full width at half maximum and a broad pedestal base about 240 mA wide. Two distinct dissociation mechanisms account for this Doppler structure. Slow H(2p) atoms characterized by a distribution function with peak energy near 80 meV produce the peak profile, which is nearly independent of the electron impact energy. Slow H(2p) atoms arise from direct dissociation and predissociation of singly excited states which have a dissociation limit of 14.68 eV. The wings of H Ly-alpha arise from dissociative excitation of a series of doubly excited states which cross the Franck-Condon region between 23 and 40 eV. The profile of the wings is dependent on the electron impact energy, and the distribution function of fast H(2p) atoms is therefore dependent on the electron impact energy. The fast atom kinetic energy distribution at 100 eV electron impact energy spans the energy range from 1 to 10 eV with a peak near 4 eV. For impact energies above 23 eV the fast atoms contribute to a slightly asymmetric structure of the line profile. The absolute cross sections of the H Ly-alpha line peak and wings were measured over the range from 0 to 200 eV. Analytic model coefficients are given for the measured cross sections which can be applied to planetary atmosphere auroral and dayglow calculations. The dissociative excitation process, while one contributing process, appears insufficient by itself to explain the line broadening observed at Jupiter.

On the Doppler Velocity of Emission Line Profiles Formed in the "Coronal Contraflow" that Is the Chromosphere-Corona Mass Cycle

NASA Astrophysics Data System (ADS)

McIntosh, Scott W.; Tian, Hui; Sechler, Marybeth; De Pontieu, Bart

2012-04-01

This analysis begins to explore the complex chromosphere-corona mass cycle using a blend of imaging and spectroscopic diagnostics. Single Gaussian fits (SGFs) to hot emission line profiles (formed above 1 MK) at the base of coronal loop structures indicate material blueshifts of 5-10 km s-1, while cool emission line profiles (formed below 1 MK) yield redshifts of a similar magnitude—indicating, to zeroth order, that a temperature-dependent bifurcating flow exists on coronal structures. Image sequences of the same region reveal weakly emitting upward propagating disturbances in both hot and cool emission with apparent speeds of 50-150 km s-1. Spectroscopic observations indicate that these propagating disturbances produce a weak emission component in the blue wing at commensurate speed, but that they contribute only a few percent to the (ensemble) emission line profile in a single spatio-temporal resolution element. Subsequent analysis of imaging data shows material "draining" slowly (~10 km s-1) out of the corona, but only in the cooler passbands. We interpret the draining as the return flow of coronal material at the end of the complex chromosphere-corona mass cycle. Further, we suggest that the efficient radiative cooling of the draining material produces a significant contribution to the red wing of cool emission lines that is ultimately responsible for their systematic redshift as derived from an SGF when compared to those formed in hotter (conductively dominated) domains. The presence of counterstreaming flows complicates the line profiles, their interpretation, and asymmetry diagnoses, but allows a different physical picture of the lower corona to develop.

Gene expression profiling of breast cancer cell lines treated with proton and electron radiations.

PubMed

Bravatà, Valentina; Minafra, Luigi; Cammarata, Francesco Paolo; Pisciotta, Pietro; Lamia, Debora; Marchese, Valentina; Manti, Lorenzo; Cirrone, Giuseppe Ap; Gilardi, Maria Carla; Cuttone, Giacomo; Forte, Giusi Irma; Russo, Giorgio

2018-06-11

Technological advances in radiation therapy are evolving with the use of hadrons, such as protons, indicated for tumors where conventional radiotherapy does not give significant advantages or for tumors located in sensitive regions, which need the maximum of dose-saving of the surrounding healthy tissues. The genomic response to conventional and non conventional Linear Energy Transfer exposure is a poor investigated topic and became an issue of radiobiological interest. The aim of this work was to analyze and compare molecular responses in term of gene expression profiles, induced by electron and proton irradiation in breast cancer cell lines. We studied the gene expression profiling differences by cDNA microarray activated in response to electron and proton irradiation with different Linear Energy Transfer values, among three breast cell lines (the tumorigenic MCF7 and MDA-MB-231 and the non tumorigenic MCF10A), exposed to the same sub-lethal dose of 9 Gy. Gene expression profiling pathway analyses showed the activation of different signaling and molecular networks in a cell line and radiation type-dependent manner. MCF10A and MDA-MB-231 cell lines were found to induce factors and pathways involved in the immunological process control. Here we describe in a detailed way the gene expression profiling and pathways activated after electron and proton irradiation in breast cancer cells. Summarizing, although specific pathways are activated in a radiation type-dependent manner, each cell line activates overall similar molecular networks in response to both these two types of ionizing radiation. Advances in knowledge: In the era of personalized medicine and breast cancer target-directed intervention, we trust that this study could drive radiation therapy towards personalized treatments, evaluating possible combined treatments, based on the molecular characterization.

Defect of focus in two-line resolution with Hanning amplitude filters

NASA Astrophysics Data System (ADS)

Karunasagar, D.; Bhikshamaiah, G.; Keshavulu Goud, M.; Lacha Goud, S.

In the presence of defocusing the modified Sparrow limits of resolution for two-line objects have been investigated for a diffraction-limited coherent optical system apodized by generalized Hanning amplitude filters. These limits have been studied as a function of different parameters such as intensity ratio, the order of the filter for various amounts of apodization parameter. Results reveal that in some situations the defocusing is effective in enhancing the resolution of an optical system.

Anticancer and enhanced antimicrobial activity of biosynthesizd silver nanoparticles against clinical pathogens

NASA Astrophysics Data System (ADS)

Rajeshkumar, Shanmugam; Malarkodi, Chelladurai; Vanaja, Mahendran; Annadurai, Gurusamy

2016-07-01

The present investigation shows the biosynthesis of eco-friendly silver nanoparticles using culture supernatant of Enterococcus sp. and study the effect of enhanced antimicrobial activity, anticancer activity against pathogenic bacteria, fungi and cancer cell lines. Silver nanoparticles was synthesized by adding 1 mM silver nitrate into the 100 ml of 24 h freshly prepared culture supernatant of Enterococcus sp. and were characterized by UV-vis spectroscopy, X-ray diffraction (XRD), Transmission Electron Microscope (TEM), Selected Area Diffraction X-Ray (SAED), Energy Dispersive X Ray (EDX) and Fourier Transform Infra red Spectroscopy (FT-IR). The synthesized silver nanoparticles were impregnated with commercial antibiotics for evaluation of enhanced antimicrobial activity. Further these synthesized silver nanoparticles were assessed for its anticancer activity against cancer cell lines. In this study crystalline structured nanoparticles with spherical in the size ranges from 10 to 80 nm and it shows excellent enhanced antimicrobial activity than the commercial antibiotics. The in vitro assay of silver nanoparticles on anticancer have great potential to inhibit the cell viability. Amide linkages and carboxylate groups of proteins from Enterococcus sp. may bind with silver ions and convert into nanoparticles. The activities of commercial antibiotics were enhanced by coating silver nanoparticles shows significant improved antimicrobial activity. Silver nanoparticles have the great potential to inhibit the cell viability of liver cancer cells lines (HepG2) and lung cancer cell lines (A549).

Diffractometric Detection of Proteins using Microbead-based Rolling Circle Amplification

PubMed Central

Lee, Joonhyung; Icoz, Kutay; Roberts, Ana; Ellington, Andrew D.; Savran, Cagri A.

2010-01-01

We present a robust, sensitive, fluorescent or radio label-free self-assembled optical diffraction biosensor that utilizes rolling circle amplification (RCA) and magnetic microbeads as a signal enhancement method. An aptamer-based sandwich assay was performed on microcontact-printed streptavidin arranged in 15-μm-wide alternating lines, and could specifically capture and detect platelet-derived growth factor B-chain (PDGF-BB). An aptamer served as a template for the ligation of a padlock probe and the circularized probe could in turn be used as a template for RCA. The concatameric RCA product hybridized to biotinylated oligonuclotides which then captured streptavidin-labeled magnetic beads. In consequence, the signal from the captured PDGF-BB was amplified via the concatameric RCA product, and the diffraction gratings on the printed areas produced varying intensities of diffraction modes. The detected diffraction intensity and the density of the microbeads on the surface varied as a function of PDGF-BB concentration. Our results demonstrate a robust biosensing platform that is easy to construct and use, and devoid of fluorescence microscopy. The self-assembled bead patterns allow both a visual analysis of the molecular binding events under an ordinary bright-field microscope and serve as a diffraction grating biosensor. PMID:19947589

Defect ordering in YBa 2Cu 3O 6.5 and YBa 2Cu 3O 6.6: Synthesis and characterization by neutron and electron diffraction

NASA Astrophysics Data System (ADS)

Lin, Y. P.; Greedan, J. E.; O'Reilly, A. H.; Reimers, J. N.; Stager, C. V.; Post, M. L.

1990-02-01

Polycrystalline samples of YBa 2Cu 3O 6.5 and YBa 2Cu 3O 6.6 were prepared by oxygen titration of YBa 2 Cu 3O 6.0 at 450°C followed by slow cooling to room temperature. Both samples showed evidence for the a' = 2a supercell in individual grains by electron diffraction as reported previously. In addition the superlattice was observed in neutron powder diffraction indicating that the bulk material is also well ordered. In this study the YBa 2Cu 3O 6.6 phase showed longer correlation lengths for ordering along both a* and b* than YBa 2Cu 3O 6.5. For the former compound the powder-averaged, sample-averaged a* correlation distance is 26A˚from neutron diffraction. Analysis of electron diffraction profiles on selected single crystals give correlation lengths along a*, b*, and c* of 100, 200, and 50A˚, respectively. Dark field imaging discloses the presence of striped, ordered domains elongated along b* with a distribution of sizes. Both neutron diffraction and dark field imaging indicate that the volume fraction of the ordered domains is about 50%. A correlation is noted between the Meissner Effect and the extent of defect ordering in the bulk samples of the two phases.

Three-dimensional modeling of the Ca II H and K lines in the solar atmosphere

NASA Astrophysics Data System (ADS)

Bjørgen, Johan P.; Sukhorukov, Andrii V.; Leenaarts, Jorrit; Carlsson, Mats; de la Cruz Rodríguez, Jaime; Scharmer, Göran B.; Hansteen, Viggo H.

2018-03-01

Context. CHROMIS, a new imaging spectrometer at the Swedish 1-m Solar Telescope (SST), can observe the chromosphere in the H and K lines of Ca II at high spatial and spectral resolution. Accurate modeling as well as an understanding of the formation of these lines are needed to interpret the SST/CHROMIS observations. Such modeling is computationally challenging because these lines are influenced by strong departures from local thermodynamic equilibrium, three-dimensional radiative transfer, and partially coherent resonance scattering of photons. Aim. We aim to model the Ca II H and K lines in 3D model atmospheres to understand their formation and to investigate their diagnostic potential for probing the chromosphere. Methods: We model the synthetic spectrum of Ca II using the radiative transfer code Multi3D in three different radiation-magnetohydrodynamic model atmospheres computed with the Bifrost code. We classify synthetic intensity profiles according to their shapes and study how their features are related to the physical properties in the model atmospheres. We investigate whether the synthetic data reproduce the observed spatially-averaged line shapes, center-to-limb variation and compare this data with SST/CHROMIS images. Results: The spatially-averaged synthetic line profiles show too low central emission peaks, and too small separation between the peaks. The trends of the observed center-to-limb variation of the profiles properties are reproduced by the models. The Ca II H and K line profiles provide a temperature diagnostic of the temperature minimum and the temperature at the formation height of the emission peaks. The Doppler shift of the central depression is an excellent probe of the velocity in the upper chromosphere.

The Effect of Changes in the ASCA Calibration on the Fe-K Lines in Active Galaxies

NASA Technical Reports Server (NTRS)

Yaqoob, T.; Padmanabhan, U.; Dotani, T.; Nandra, K.; White, Nicholas E. (Technical Monitor)

2001-01-01

The ASCA calibration has evolved considerably since launch and indeed, is still evolving. There have been concerns in the literature that changes in the ASCA calibration have resulted in the Fe-K lines in active galaxies (AGN) now being systematically narrower than was originally thought. If this were true, a large body of ASCA results would be impacted. In particular, it has been claimed that the broad red wing (when present) of the Fe-K line has been considerably weakened by changes in the ASCA calibration. We demonstrate explicitly that changes in the, ASCA calibration over a period of about eight years have a negligible effect on the width, strength, or shape of the Fe-K lines. The reduction in both width and equivalent width is only approximately 8% or less. We confirm this with simulations and individual sources, as well as sample average profiles. The average profile for type 1 AGN is still very broad, with the red wing extending down to approximately 4 keV. The reason for the claimed, apparently large, discrepancies is that in some sources the Fe-K line is complex, and a single-Gaussian model, being an inadequate description of the line profile, picks up different portions of the profile with different calibration. However, one cannot make inferences about calibration or astrophysics of the sources using models which do not describe the data. Better modeling of the Fe-K in such cases gives completely consistent results with both old and current calibration. Thus, inadequate modeling of the Fe-K line in these sources can seriously underestimate the line width and equivalent width, and therefore lead to incorrect deductions about the astrophysical implications.

Non-Maxwellian Analysis of the Transition-region Line Profiles Observed by the Interface Region Imaging Spectrograph

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dudík, Jaroslav; Dzifčáková, Elena; Polito, Vanessa

2017-06-10

We investigate the nature of the spectral line profiles for transition-region (TR) ions observed with the Interface Region Imaging Spectrograph (IRIS) . In this context, we analyzed an active-region observation performed by IRIS in its 1400 Å spectral window. The TR lines are found to exhibit significant wings in their spectral profiles, which can be well fitted with a non-Maxwellian κ distribution. The fit with a κ distribution can perform better than a double-Gaussian fit, especially for the strongest line, Si iv 1402.8 Å. Typical values of κ found are about 2, occurring in a majority of spatial pixels wheremore » the TR lines are symmetric, i.e., the fit can be performed. Furthermore, all five spectral lines studied (from Si iv, O iv, and S iv) appear to have the same full-width at half-maximum irrespective of whether the line is an allowed or an intercombination transition. A similar value of κ is obtained for the electron distribution by the fitting of the line intensities relative to Si iv 1402.8 Å, if photospheric abundances are assumed. The κ distributions, however, do not remove the presence of non-thermal broadening. Instead, they actually increase the non-thermal width. This is because, for κ distributions, TR ions are formed at lower temperatures. The large observed non-thermal width lowers the opacity of the Si iv line sufficiently enough for this line to become optically thin.« less

High resolution humidity, temperature and aerosol profiling with MeteoSwiss Raman lidar

NASA Astrophysics Data System (ADS)

Dinoev, Todor; Arshinov, Yuri; Bobrovnikov, Sergei; Serikov, Ilya; Calpini, Bertrand; van den Bergh, Hubert; Parlange, Marc B.; Simeonov, Valentin

2010-05-01

Meteorological services rely, in part, on numerical weather prediction (NWP). Twice a day radiosonde observations of water vapor provide the required data for assimilation but this time resolution is insufficient to resolve certain meteorological phenomena. High time resolution temperature profiles from microwave radiometers are available as well but have rather low vertical resolution. The Raman LIDARs are able to provide temperature and humidity profiles with high time and range resolution, suitable for NWP model assimilation and validation. They are as well indispensible tools for continuous aerosol profiling for high resolution atmospheric boundary layer studies. To improve the database available for direct meteorological applications the Swiss meteo-service (MeteoSwiss), the Swiss Federal Institute of Technology in Lausanne (EPFL) and the Swiss National Science Foundation (SNSF) initiated a project to design and build an automated Raman lidar for day and night vertical profiling of tropospheric water vapor with the possibility to further upgrade it with an aerosol and temperature channels. The project was initiated in 2004 and RALMO (Raman Lidar for meteorological observations) was inaugurated in August 2008 at MeteoSwiss aerological station at Payerne. RALMO is currently operational and continuously profiles water vapor mixing ratio, aerosol backscatter ratio and aerosol extinction. The instrument is a fully automated, self-contained, eye-safe Raman lidar operated at 355 nm. Narrow field-of-view multi-telescope receiver and narrow band detection allow day and night-time vertical profiling of the atmospheric humidity. The rotational-vibrational Raman lidar responses from water vapor and nitrogen are spectrally separated by a high-throughput fiber coupled diffraction grating polychromator. The elastic backscatter and pure-rotational Raman lidar responses (PRR) from oxygen and nitrogen are spectrally isolated by a double grating polychromator and are used to derive vertical profiles of aerosol backscatter ratio and aerosol extinction at 355 nm. Set of Stokes and anti-Stokes PRR lines are separated by the polychromator to derive temperature profiles. The humidity profiles have vertical resolution from 15 m (within the boundary layer) to 100-450 m (within the free troposphere), time resolution of 30 min and 5 km vertical range at daytime and 10 km at night-time. The aerosol backscatter ratio and extinction profiles have similar resolution with vertical range of approximately 10 km. The temperature profiles are derived from PRR lidar signals, simultaneously recorded in analog and photon counting mode, allowing vertical range of approximately 10 km. Vaisala RS-92 and Snow-White chilled mirror hygrometer radiosondes were used for calibration of the water vapor and temperature channels. Continuous temperature profiles were obtained and were coupled with the available water vapor mixing ratio profiles to obtain relative humidity time series. Lidar derived aerosol backscatter ratio profiles will be used for estimation of the boundary layer height and validation of NWP model results. Optical thickness time series are currently compared to independent measurements from a collocated sun photometer to assess the performance of the aerosol channel.

Comparison of Solar Fine Structure Observed Simultaneously in Lyα and Mg II h

NASA Astrophysics Data System (ADS)

Schmit, D.; Sukhorukov, A. V.; De Pontieu, B.; Leenaarts, J.; Bethge, C.; Winebarger, A.; Auchère, F.; Bando, T.; Ishikawa, R.; Kano, R.; Kobayashi, K.; Narukage, N.; Trujillo Bueno, J.

2017-10-01

The Chromospheric Lyman Alpha Spectropolarimeter (CLASP) observed the Sun in H I Lyα during a suborbital rocket flight on 2015 September 3. The Interface Region Imaging Telescope (IRIS) coordinated with the CLASP observations and recorded nearly simultaneous and co-spatial observations in the Mg II h and k lines. The Mg II h and Lyα lines are important transitions, energetically and diagnostically, in the chromosphere. The canonical solar atmosphere model predicts that these lines form in close proximity to each other and so we expect that the line profiles will exhibit similar variability. In this analysis, we present these coordinated observations and discuss how the two profiles compare over a region of quiet Sun at viewing angles that approach the limb. In addition to the observations, we synthesize both line profiles using a 3D radiation-MHD simulation. In the observations, we find that the peak width and the peak intensities are well correlated between the lines. For the simulation, we do not find the same relationship. We have attempted to mitigate the instrumental differences between IRIS and CLASP and to reproduce the instrumental factors in the synthetic profiles. The model indicates that formation heights of the lines differ in a somewhat regular fashion related to magnetic geometry. This variation explains to some degree the lack of correlation, observed and synthesized, between Mg II and Lyα. Our analysis will aid in the definition of future observatories that aim to link dynamics in the chromosphere and transition region.

Comparison of Solar Fine Structure Observed Simultaneously in Ly α and Mg ii h

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmit, D.; Sukhorukov, A. V.; Leenaarts, J.

The Chromospheric Lyman Alpha Spectropolarimeter (CLASP) observed the Sun in H i Ly α during a suborbital rocket flight on 2015 September 3. The Interface Region Imaging Telescope ( IRIS ) coordinated with the CLASP observations and recorded nearly simultaneous and co-spatial observations in the Mg ii h and k lines. The Mg ii h and Ly α lines are important transitions, energetically and diagnostically, in the chromosphere. The canonical solar atmosphere model predicts that these lines form in close proximity to each other and so we expect that the line profiles will exhibit similar variability. In this analysis, wemore » present these coordinated observations and discuss how the two profiles compare over a region of quiet Sun at viewing angles that approach the limb. In addition to the observations, we synthesize both line profiles using a 3D radiation-MHD simulation. In the observations, we find that the peak width and the peak intensities are well correlated between the lines. For the simulation, we do not find the same relationship. We have attempted to mitigate the instrumental differences between IRIS and CLASP and to reproduce the instrumental factors in the synthetic profiles. The model indicates that formation heights of the lines differ in a somewhat regular fashion related to magnetic geometry. This variation explains to some degree the lack of correlation, observed and synthesized, between Mg ii and Ly α . Our analysis will aid in the definition of future observatories that aim to link dynamics in the chromosphere and transition region.« less

Dislocation, crystallite size distribution and lattice strain of magnesium oxide nanoparticles

NASA Astrophysics Data System (ADS)

Sutapa, I. W.; Wahid Wahab, Abdul; Taba, P.; Nafie, N. L.

2018-03-01

The oxide of magnesium nanoparticles synthesized using sol-gel method and analysis of the structural properties was conducted. The functional groups of nanoparticles has been analysed by Fourier Transform Infrared Spectroscopy (FT-IR). Dislocations, average size of crystal, strain, stress, the energy density of crystal, crystallite size distribution and morphologies of the crystals were determined based on X-ray diffraction profile analysis. The morphological of the crystal was analysed based on the image resulted from SEM analysis. The crystallite size distribution was calculated with the contention that the particle size has a normal logarithmic form. The most orientations of crystal were determined based on the textural crystal from diffraction data of X-ray diffraction profile analysis. FT-IR results showed the stretching vibration mode of the Mg-O-Mg in the range of 400.11-525 cm-1 as a broad band. The average size crystal of nanoparticles resulted is 9.21 mm with dislocation value of crystal is 0.012 nm-2. The strains, stress, the energy density of crystal are 1.5 x 10-4 37.31 MPa; 0.72 MPa respectively. The highest texture coefficient value of the crystal is 0.98. This result is supported by morphological analysis using SEM which shows most of the regular cubic-shaped crystals. The synthesis method is suitable for simple and cost-effective synthesis model of MgO nanoparticles.

The classification of secondary colorectal liver cancer in human biopsy samples using angular dispersive x-ray diffraction and multivariate analysis

NASA Astrophysics Data System (ADS)

Theodorakou, Chrysoula; Farquharson, Michael J.

2009-08-01

The motivation behind this study is to assess whether angular dispersive x-ray diffraction (ADXRD) data, processed using multivariate analysis techniques, can be used for classifying secondary colorectal liver cancer tissue and normal surrounding liver tissue in human liver biopsy samples. The ADXRD profiles from a total of 60 samples of normal liver tissue and colorectal liver metastases were measured using a synchrotron radiation source. The data were analysed for 56 samples using nonlinear peak-fitting software. Four peaks were fitted to all of the ADXRD profiles, and the amplitude, area, amplitude and area ratios for three of the four peaks were calculated and used for the statistical and multivariate analysis. The statistical analysis showed that there are significant differences between all the peak-fitting parameters and ratios between the normal and the diseased tissue groups. The technique of soft independent modelling of class analogy (SIMCA) was used to classify normal liver tissue and colorectal liver metastases resulting in 67% of the normal tissue samples and 60% of the secondary colorectal liver tissue samples being classified correctly. This study has shown that the ADXRD data of normal and secondary colorectal liver cancer are statistically different and x-ray diffraction data analysed using multivariate analysis have the potential to be used as a method of tissue classification.

Rietveld analysis of X-ray powder diffraction patterns as a potential tool for the identification of impact-deformed carbonate rocks

NASA Astrophysics Data System (ADS)

Huson, S. A.; Foit, F. F.; Watkinson, A. J.; Pope, M. C.

2009-12-01

Previous X-ray powder diffraction (XRD) studies revealed that shock deformed carbonates and quartz have broader XRD patterns than those of unshocked samples. Entire XRD patterns, single peak profiles and Rietveld refined parameters of carbonate samples from the Sierra Madera impact crater, west Texas, unshocked equivalent samples from 95 miles north of the crater and the Mission Canyon Formation of southwest Montana and western Wyoming were used to evaluate the use of X-ray powder diffraction as a potential tool for distinguishing impact deformed rocks from unshocked and tectonically deformed rocks. At Sierra Madera dolostone and limestone samples were collected from the crater rim (lower shock intensity) and the central uplift (higher shock intensity). Unshocked equivalent dolostone samples were collected from well cores drilled outside of the impact crater. Carbonate rocks of the Mission Canyon Formation were sampled along a transect across the tectonic front of the Sevier and Laramide orogenic belts. Whereas calcite subjected to significant shock intensities at the Sierra Madera impact crater can be differentiated from tectonically deformed calcite from the Mission Canyon Formation using Rietveld refined peak profiles, weakly shocked calcite from the crater rim appears to be indistinguishable from the tectonically deformed calcite. In contrast, Rietveld analysis readily distinguishes shocked Sierra Madera dolomite from unshocked equivalent dolostone samples from outside the crater and tectonically deformed Mission Canyon Formation dolomite.

Impurity profiles and radial transport in the EXTRAP-T2 reversed field pinch

NASA Astrophysics Data System (ADS)

Sallander, J.

1999-05-01

Radially resolved spectroscopy has been used to measure the radial distribution of impurity ions (O III-O V and C III-CVI) in the EXTRAP-T2 reversed field pinch (RFP). The radial profile of the emission is reconstructed from line emission measured along five lines of sight. The ion density profile is the fitted quantity in the reconstruction of the brightness profile and is thus obtained directly in this process. These measurements are then used to adjust the parameters in transport calculations in order to obtain consistency with the observed ion density profiles. Comparison between model and measurements show that a radial dependence in the diffusion is needed to explain the measured ion densities.

The IACOB project . III. New observational clues to understand macroturbulent broadening in massive O- and B-type stars

NASA Astrophysics Data System (ADS)

Simón-Díaz, S.; Godart, M.; Castro, N.; Herrero, A.; Aerts, C.; Puls, J.; Telting, J.; Grassitelli, L.

2017-01-01

Context. The term macroturbulent broadening is commonly used to refer to a certain type of non-rotational broadening affecting the spectral line profiles of O- and B-type stars. It has been proposed to be a spectroscopic signature of the presence of stellar oscillations; however, we still lack a definitive confirmation of this hypothesis. Aims: We aim to provide new empirical clues about macroturbulent spectral line broadening in O- and B-type stars to evaluate its physical origin. Methods: We used high-resolution spectra of 430 stars with spectral types in the range O4 - B9 (all luminosity classes) compiled in the framework of the IACOB project. We characterized the line broadening of adequate diagnostic metal lines using a combined Fourier transform and goodness-of-fit technique. We performed a quantitative spectroscopic analysis of the whole sample using automatic tools coupled with a huge grid of fastwind models to determine their effective temperatures and gravities. We also incorporated quantitative information about line asymmetries into our observational description of the characteristics of the line profiles, and performed a comparison of the shape and type of line-profile variability found in a small sample of O stars and B supergiants with still undefined pulsational properties and B main-sequence stars with variable line profiles owing to a well-identified type of stellar oscillations or to the presence of spots in the stellar surface. Results: We present a homogeneous and statistically significant overview of the (single snapshot) line-broadening properties of stars in the whole O and B star domain. We find empirical evidence of the existence of various types of non-rotational broadening agents acting in the realm of massive stars. Even though all these additional sources of line-broadening could be quoted and quantified as a macroturbulent broadening from a practical point of view, their physical origin can be different. Contrarily to the early- to late-B dwarfs and giants, which present a mixture of cases in terms of line-profile shape and variability, the whole O-type and B supergiant domain (or, roughly speaking, stars with MZAMS ≳ 15 M⊙) is fully dominated by stars with a remarkable non-rotational broadening component and very similar profiles (including type of variability). We provide some examples illustrating how this observational dataset can be used to evaluate scenarios aimed at explaining the existence of sources of non-rotational broadening in massive stars. Full Table 1 is only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/597/A22

The Life and Work of Joseph Fraunhofer (1787-1826)

ERIC Educational Resources Information Center

Leitner, Alfred

1975-01-01

Describes Fraunhofer's scientific career as a glass and lens maker, a discoverer of dark lines in the solar spectrum, a corrector of lens aberration, and investigator of diffraction. Gives biographical data and anecdotes. Includes a bibliography, mainly of German sources. (GH)

Photospheres of hot stars. III - Luminosity effects at spectral type 09.5

NASA Technical Reports Server (NTRS)

Voels, Stephen A.; Bohannan, Bruce; Abbott, David C.; Hummer, D. G.

1989-01-01

Hydrogen and helium line profiles with high signal-to-noise ratios were obtained for four stars of spectral type 09.5 (Alpha Cam, Xi Ori A, Delta Ori A,AE Aur) that form a sequence in luminosity: Ia, Ib, II, V. The basic stellar parameters of these stars are determined by fitting the observed line profiles of weak photospheric absorption lines with profiles from models which include the effect of radiation scattered back onto the photosphere from their stellar winds, an effect referred to as wind blanketing. For these stars, the inclusion of wind blanketing is significant only for the most luminous star, Alpha Cam, for which the effective temperature was shifted about -2000 K relative to an unblanketed model.

Application of Mythen detector: In-situ XRD study on the thermal expansion behavior of metal indium

NASA Astrophysics Data System (ADS)

Du, Rong; Chen, ZhongJun; Cai, Quan; Fu, JianLong; Gong, Yu; Wu, ZhongHua

2016-07-01

A Mythen detector has been equipped at the beamline 4B9A of Beijing Synchrotron Radiation Facility (BSRF), which is expected to enable BSRF to perform time-resolved measurement of X-ray diffraction (XRD) full-profiles. In this paper, the thermal expansion behavior of metal indium has been studied by using the in-situ XRD technique with the Mythen detector. The indium was heated from 303 to 433 K with a heating rate of 2 K/min. The in-situ XRD full-profiles were collected with a rate of one profile per 10 seconds. Rietveld refinement was used to extract the structural parameters. The results demonstrate that these collected quasi-real-time XRD profiles can be well used for structural analysis. The metal indium was found to have a nonlinear thermal expansion behavior from room temperature to the melting point (429.65 K). The a-axis of the tetragonal unit cell expands with a biquadratic dependency on temperature, while the c-axis contracts with a cubic dependency on temperature. By the time-resolved XRD measurements, it was observed that the [200] preferred orientation can maintain to about 403.15 K. While (110) is the last and detectable crystal plane just before melting of the polycrystalline indium foil. This study is not only beneficial to the application of metal indium, but also exhibits the capacity of in-situ time-resolved XRD measurements at the X-ray diffraction station of BSRF.

Synthesis, stereochemistry determination, pharmacological studies and quantum chemical analyses of bisthiazolidinone derivative

NASA Astrophysics Data System (ADS)

Mushtaque, Md.; Avecilla, Fernando; Hafeez, Zubair Bin; Jahan, Meriyam; Khan, Md. Shahzad; Rizvi, M. Moshahid A.; Khan, Mohd. Shahid; Srivastava, Anurag; Mallik, Anwesha; Verma, Saurabh

2017-01-01

A new compound (3) bisthaizolidinone derivative was synthesized by Knoevenagel condensation reaction. The structure of synthesized compound was elucidated by different spectral techniques and X-ray diffraction studies. The stereochemistry of the compound (3) was determined by 1Hsbnd 1H NOESY, 1Hsbnd 1H NMR COSY and single crystal X-ray diffraction studies as (Z, Z)-configuration. The computational quantum chemical studies of compound(3) like, IR, UV, NBO analysis were performed by DFT with Becke-3-Lee-Yang-Parr (B3LYP) exchange-correlation functional in combination with 6-311++G(d,p) basis sets. The DNA-binding of compound (3) exhibited a moderate binding constant (Kb = 1 × 105 Lmol-1) with hypochromic shift. The molecular docking displayed good binding affinity -7.18 kcal/mol. The MTT assay of compound (3) was screened against different cancerous cell lines, HepG2, Siha, Hela and MCF-7. Studies against these cell lines depicted that the screened compound (3) showed potent inhibitory activity against HepG2 cell (IC50 = 7.5 μM) followed by MCF-7 (IC50 = 52.0 μM), Siha (IC50 = 66.98 μM), Hela (IC50 = 74.83 μM) cell lines, and non-toxic effect against non-cancerous HEK-293 cells (IC50 = 287.89 μM) at the concentration range (0-300) μM. Furthermore, cell cycle perturbation was performed on HepG2 & Siha cell lines and observed that cells were arrested in G2/M in HepG2, and G0/G1 in Siha cell lines with respect to untreated control. Hence, compound (3) possesses potent anti-cancerous activity against HepG2 cell line.

Nondestructive X-ray diffraction measurement of warpage in silicon dies embedded in integrated circuit packages.

PubMed

Tanner, B K; Danilewsky, A N; Vijayaraghavan, R K; Cowley, A; McNally, P J

2017-04-01

Transmission X-ray diffraction imaging in both monochromatic and white beam section mode has been used to measure quantitatively the displacement and warpage stress in encapsulated silicon devices. The displacement dependence with position on the die was found to agree well with that predicted from a simple model of warpage stress. For uQFN microcontrollers, glued only at the corners, the measured misorientation contours are consistent with those predicted using finite element analysis. The absolute displacement, measured along a line through the die centre, was comparable to that reported independently by high-resolution X-ray diffraction and optical interferometry of similar samples. It is demonstrated that the precision is greater than the spread of values found in randomly selected batches of commercial devices, making the techniques viable for industrial inspection purposes.

Spectrally-Narrowed Emissions from Organic Crystals Having a One-Dimensional Grating on Their Surface.

PubMed

Yamamoto, Hiroyuki; Obara, Keiji; Higashihara, Shohei; Obama, Yuki; Yamao, Takeshi; Hotta, Shu

2016-04-01

We have succeeded in directly engraving one-dimensional diffraction gratings on the surface of organic semiconducting oligomer crystals by using focused ion beam (FIB) lithography and laser ablation (LA) methods. The FIB method enabled us to shape the gratings with varying periods down to ~150 nm. With the LA method a large-area grating with a ~500-nm period was readily accessible. All the above crystals indicated spectrally-narrowed emission (SNE) lines even in the case of shallow groove depths ~2-4 nm. In particular, we definitively observed the SNE pertinent to the first-order diffraction with the crystal having the diffraction grating of a 148.3-nm average period. The present results indicate utility of the built-in gratings that can directly be fabricated on the surface of the crystals.

Low-resolution structure of Drosophila translin

PubMed Central

Kumar, Vinay; Gupta, Gagan D.

2012-01-01

Crystals of native Drosophila melanogaster translin diffracted to 7 Å resolution. Reductive methylation of the protein improved crystal quality. The native and methylated proteins showed similar profiles in size-exclusion chromatography analyses but the methylated protein displayed reduced DNA-binding activity. Crystals of the methylated protein diffracted to 4.2 Å resolution at BM14 of the ESRF synchrotron. Crystals with 49% solvent content belonged to monoclinic space group P21 with eight protomers in the asymmetric unit. Only 2% of low-resolution structures with similar low percentage solvent content were found in the PDB. The crystal structure, solved by molecular replacement method, refined to Rwork (Rfree) of 0.24 (0.29) with excellent stereochemistry. The crystal structure clearly shows that drosophila protein exists as an octamer, and not as a decamer as expected from gel-filtration elution profiles. The similar octameric quaternary fold in translin orthologs and in translin–TRAX complexes suggests an up-down dimer as the basic structural subunit of translin-like proteins. The drosophila oligomer displays asymmetric assembly and increased radius of gyration that accounts for the observed differences between the elution profiles of human and drosophila proteins on gel-filtration columns. This study demonstrates clearly that low-resolution X-ray structure can be useful in understanding complex biological oligomers. PMID:23650579

A controlled release of ibuprofen by systematically tailoring the morphology of mesoporous silica materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Qu Fengyu; Chemistry and Pharmaceutical College, Jiamusi University, Jiamusi 154007; Zhu Guangshan

2006-07-15

A series of mesoporous silica materials with similar pore sizes, different morphologies and variable pore geometries were prepared systematically. In order to control drug release, ibuprofen was employed as a model drug and the influence of morphology and pore geometry of mesoporous silica on drug release profiles was extensively studied. The mesoporous silica and drug-loaded samples were characterized by X-ray diffraction, Fourier transform IR spectroscopy, N{sub 2} adsorption and desorption, scanning electron microscopy, and transmission electron microscopy. It was found that the drug-loading amount was directly correlated to the Brunauer-Emmett-Teller surface area, pore geometry, and pore volume; while the drugmore » release profiles could be controlled by tailoring the morphologies of mesoporous silica carriers. - Graphical abstract: The release of ibuprofen is controlled by tailoring the morphologies of mesoporous silica. The mesoporous silica and drug-loaded samples are characterized by powder X-ray diffraction, Fourier transform IR spectroscopy, N{sub 2} adsorption and desorption, scanning electron microscopy, and transmission electron microscopy. The drug-loading amount is directly correlated to the Brunauer-Emmett-Teller surface area, pore geometry, and pore volume; while the drug release profiles can be controlled by tailoring the morphologies of mesoporous silica carriers.« less

Erratum: The 2.27 day period of WR-134 (HD 191765)

NASA Astrophysics Data System (ADS)

McCandliss, Stephan R.; Bohannan, Bruce; Robert, Carmelle; Moffat, Anthony F. J.

1994-11-01

The original temporal analysis of a 12 night spectral timeseries of Wolf-Rayet (WR)-134 has been found to be flawed and a re-analysis shows that the line profile variations are indeed periodic. When combined with a 4 night timeseries taken 45 days earlier, a period near 2.27 d is found in periodograms of the He II lambda 5412 line centroid, rms line width, and line skew variations. When the emission line residuals are ordered as a function of phase, a sinuous feature appears to 'snake' about the line center with an amplitude of +/-500 km/s. This is approximately equal to 20 larger than the line centroid amplitude; the calculation of which is heavily weighted by static portions of the line profile. In addition to the 'snake,' emission residuals appear that move away from line center on unbound trajectories and are thought to result from the interaction of a periodic driver with the unstable flow of the radiation driven wind.

Erratum: The 2.27 day period of WR-134 (HD 191765)

NASA Technical Reports Server (NTRS)

Mccandliss, Stephan R.; Bohannan, Bruce; Robert, Carmelle; Moffat, Anthony F. J.

1994-01-01

The original temporal analysis of a 12 night spectral timeseries of Wolf-Rayet (WR)-134 has been found to be flawed and a re-analysis shows that the line profile variations are indeed periodic. When combined with a 4 night timeseries taken 45 days earlier, a period near 2.27 d is found in periodograms of the He II lambda 5412 line centroid, rms line width, and line skew variations. When the emission line residuals are ordered as a function of phase, a sinuous feature appears to 'snake' about the line center with an amplitude of +/-500 km/s. This is approximately equal to 20 larger than the line centroid amplitude; the calculation of which is heavily weighted by static portions of the line profile. In addition to the 'snake,' emission residuals appear that move away from line center on unbound trajectories and are thought to result from the interaction of a periodic driver with the unstable flow of the radiation driven wind.