'Ab initio' structure solution from electron diffraction data obtained by a combination of automated diffraction tomography and precession technique

International Nuclear Information System (INIS)

Mugnaioli, E.; Gorelik, T.; Kolb, U.

2009-01-01

Using a combination of our recently developed automated diffraction tomography (ADT) module with precession electron technique (PED), quasi-kinematical 3D diffraction data sets of an inorganic salt (BaSO 4 ) were collected. The lattice cell parameters and their orientation within the data sets were found automatically. The extracted intensities were used for 'ab initio' structure analysis by direct methods. The data set covered almost the complete set of possible symmetrically equivalent reflections for an orthorhombic structure. The structure solution in one step delivered all heavy (Ba, S) as well as light atoms (O). Results of the structure solution using direct methods, charge flipping and maximum entropy algorithms as well as structure refinement for three different 3D electron diffraction data sets were presented.

Diffraction. Powder, amorphous, liquid

International Nuclear Information System (INIS)

Sosnowska, I.M.

1999-01-01

Neutron powder diffraction is a unique tool to observe all possible diffraction effects appearing in crystal. High-resolution neutron diffractometers have to be used in this study. Analysis of the magnetic structure of polycrystalline materials requires the use of high-resolution neutron diffraction in the range of large interplanar distances. As distinguished from the double axis diffractometers (DAS), which show high resolution only at small interplanar distances, TOF (time-of-flight) diffractometry offers the best resolution at large interplanar distances. (K.A.)

Thermal diffuse scattering in angular-dispersive neutron diffraction

International Nuclear Information System (INIS)

Popa, N.C.; Willis, B.T.M.

1998-01-01

The theoretical treatment of one-phonon thermal diffuse scattering (TDS) in single-crystal neutron diffraction at fixed incident wavelength is reanalysed in the light of the analysis given by Popa and Willis [Acta Cryst. (1994), (1997)] for the time-of-flight method. Isotropic propagation of sound with different velocities for the longitudinal and transverse modes is assumed. As in time-of-flight diffraction, there exists, for certain scanning variables, a forbidden range in the one-phonon TDS of slower-than-sound neutrons, and this permits the determination of the sound velocity in the crystal. A fast algorithm is given for the TDS correction of neutron diffraction data collected at a fixed wavelength: this algorithm is similar to that reported earlier for the time-of-flight case. (orig.)

Modern techniques of structural neutron diffraction

International Nuclear Information System (INIS)

Aksenov, V.L.; )

1997-01-01

Modern techniques of neutron diffraction for structural investigations are analyzed. The time-of-flight method and the reverse time-of-flight method are considered briefly. Characteristics of two-crystal and time-of-flight neutron diffractometers are compared. It is pointed that in the future, the great importance will be possessed the development of high-resolution Fourier neutron diffractometers [ru

Status of the Neutron Imaging and Diffraction Instrument IMAT

Science.gov (United States)

Kockelmann, Winfried; Burca, Genoveva; Kelleher, Joe F.; Kabra, Saurabh; Zhang, Shu-Yan; Rhodes, Nigel J.; Schooneveld, Erik M.; Sykora, Jeff; Pooley, Daniel E.; Nightingale, Jim B.; Aliotta, Francesco; Ponterio, Rosa C.; Salvato, Gabriele; Tresoldi, Dario; Vasi, Cirino; McPhate, Jason B.; Tremsin, Anton S.

A cold neutron imaging and diffraction instrument, IMAT, is currently being constructed at the ISIS second target station. IMAT will capitalize on time-of-flight transmission and diffraction techniques available at a pulsed neutron source. Analytical techniques will include neutron radiography, neutron tomography, energy-selective neutron imaging, and spatially resolved diffraction scans for residual strain and texture determination. Commissioning of the instrument will start in 2015, with time-resolving imaging detectors and two diffraction detector prototype modules. IMAT will be operated as a user facility for material science applications and will be open for developments of time-of-flight imaging methods.

Neutron diffraction on pulsed sources

International Nuclear Information System (INIS)

Aksenov, V.L.; Balagurov, A.M.

2016-01-01

The possibilities currently offered and major scientific problems solved by time-of-flight neutron diffraction are reviewed. The reasons for the rapid development of the method over the last two decades has been mainly the emergence of third generation pulsed sources with a MW time-averaged power and advances in neutron-optical devices and detector systems. The paper discusses some historical aspects of time-of-flight neutron diffraction and examines the contribution to this method by F.L.Shapiro whose 100th birth anniversary was celebrated in 2015. The state of the art with respect to neutron sources for studies on output beams is reviewed in a special section. [ru

Measurement of residual strain in composites by means of time-of- flight neutron diffraction

International Nuclear Information System (INIS)

Kupperman, D.S.; Majumdar, S.; Richardson, J.; Saigal, A.

1993-01-01

Neutron diffraction time-of-flight measurements using the Intense Pulsed Neutron Source at Argonne National Laboratory have been employed to study strain in various metal- and ceramic-matrix composites. For example, measurements carried out to 900 C on a composite composed of a titanium alloy matrix and silicon carbide fibers have been used to validate theoretical assumptions in the prediction of fabrication-induced residual stress. Sapphire reinforced nickel aluminide composites have also been studied. Studies of a high-temperature ceramic superconducting composite consisting of yttrium barium copper oxide and silver with various volume fractions of silver have also been carried out. The results of these studies have provided information on the effect of Ag content on interface bonding. In addition, ceramic-matrix composites with randomly dispersed ceramic whiskers with varying fiber content have been investigated

On the combination of molecular replacement and single-wavelength anomalous diffraction phasing for automated structure determination

International Nuclear Information System (INIS)

Panjikar, Santosh; Parthasarathy, Venkataraman; Lamzin, Victor S.; Weiss, Manfred S.; Tucker, Paul A.

2009-01-01

The combination of molecular replacement and single-wavelength anomalous diffraction improves the performance of automated structure determination with Auto-Rickshaw. A combination of molecular replacement and single-wavelength anomalous diffraction phasing has been incorporated into the automated structure-determination platform Auto-Rickshaw. The complete MRSAD procedure includes molecular replacement, model refinement, experimental phasing, phase improvement and automated model building. The improvement over the standard SAD or MR approaches is illustrated by ten test cases taken from the JCSG diffraction data-set database. Poor MR or SAD phases with phase errors larger than 70° can be improved using the described procedure and a large fraction of the model can be determined in a purely automatic manner from X-ray data extending to better than 2.6 Å resolution

Combining MHD Airbreathing and Fusion Rocket Propulsion for Earth-to-Orbit Flight

International Nuclear Information System (INIS)

Froning, H. D. Jr; Yang, Yang; Momota, H.; Burton, E.; Miley, G. H.; Luo, Nie

2005-01-01

Previous studies have shown that Single-State-to-Orbit (SSTO) vehicle propellant can be reduced by Magnets-Hydro-Dynamic (MHD) processes that minimize airbreathing propulsion losses and propellant consumption during atmospheric flight. Similarly additional reduction in SSTO propellant is enabled by Inertial Electrostatic Confinement (IEC) fusion, whose more energetic reactions reduce rocket propellant needs. MHD airbreathing propulsion during an SSTO vehicle's initial atmospheric flight phase and IEC fusion propulsion during its final exo-atmospheric flight phase is therefore being explored. Accomplished work is not yet sufficient for claiming such a vehicle's feasibility. But takeoff and propellant mass for an MHD airbreathing and IEC fusion vehicle could be as much as 25 and 40 percent less than one with ordinary airbreathing and IEC fusion; and as much as 50 and 70 percent less than SSTO takeoff and propellant mass with MHD airbreathing and chemical rocket propulsion. Thus this unusual combined cycle engine shows great promise for performance gains beyond contemporary combined-cycle airbreathing engines

Combining zonal refractive and diffractive aspheric multifocal intraocular lenses.

Science.gov (United States)

Muñoz, Gonzalo; Albarrán-Diego, César; Javaloy, Jaime; Sakla, Hani F; Cerviño, Alejandro

2012-03-01

To assess visual performance with the combination of a zonal refractive aspheric multifocal intraocular lens (MIOL) (Lentis Mplus, Oculentis GmbH) and a diffractive aspheric MIOL (Acri.Lisa 366, Acri.Tech GmbH). This prospective interventional cohort study comprised 80 eyes from 40 cataract patients (mean age: 65.5±7.3 years) who underwent implantation of the Lentis Mplus MIOL in one eye and Acri.Lisa 366 MIOL in the fellow eye. The main outcome measures were refraction; monocular and binocular uncorrected and corrected distance, intermediate, and near visual acuities; monocular and binocular defocus curves; binocular photopic contrast sensitivity function compared to a monofocal intraocular lens (IOL) control group (40 age-matched pseudophakic patients implanted with the AR-40e [Abbott Medical Optics]); and quality of vision questionnaire. Binocular uncorrected visual acuities were 0.12 logMAR (0.76 decimal) or better at all distances measured between 6 m and 33 cm. The Lentis Mplus provided statistically significant better vision than the Acri.Lisa at distances between 2 m and 40 cm, and the Acri.Lisa provided statistically significant better vision than the Lentis Mplus at 33 cm. Binocular defocus curve showed little drop-off at intermediate distances. Photopic contrast sensitivity function for distance and near were similar to the monofocal IOL control group except for higher frequencies. Moderate glare (15%), night vision problems (12.5%), and halos (10%) were reported. Complete independence of spectacles was achieved by 92.5% of patients. The combination of zonal refractive aspheric and diffractive aspheric MIOLs resulted in excellent uncorrected binocular distance, intermediate, and near vision, with low incidence of significant photic phenomena and high patient satisfaction. Copyright 2012, SLACK Incorporated.

Numerical simulation of divergent rocket-based-combined-cycle performances under the flight condition of Mach 3

Science.gov (United States)

Cui, Peng; Xu, WanWu; Li, Qinglian

2018-01-01

Currently, the upper operating limit of the turbine engine is Mach 2+, and the lower limit of the dual-mode scramjet is Mach 4. Therefore no single power systems can operate within the range between Mach 2 + and Mach 4. By using ejector rockets, Rocket-based-combined-cycle can work well in the above scope. As the key component of Rocket-based-combined-cycle, the ejector rocket has significant influence on Rocket-based-combined-cycle performance. Research on the influence of rocket parameters on Rocket-based-combined-cycle in the speed range of Mach 2 + to Mach 4 is scarce. In the present study, influences of Mach number and total pressure of the ejector rocket on Rocket-based-combined-cycle were analyzed numerically. Due to the significant effects of the flight conditions and the Rocket-based-combined-cycle configuration on Rocket-based-combined-cycle performances, flight altitude, flight Mach number, and divergence ratio were also considered. The simulation results indicate that matching lower altitude with higher flight Mach numbers can increase Rocket-based-combined-cycle thrust. For another thing, with an increase of the divergent ratio, the effect of the divergent configuration will strengthen and there is a limit on the divergent ratio. When the divergent ratio is greater than the limit, the effect of divergent configuration will gradually exceed that of combustion on supersonic flows. Further increases in the divergent ratio will decrease Rocket-based-combined-cycle thrust.

Crack sizing by the time-of-flight diffraction method, in the light of recent international round-robin trials, (UKAEA, DDT and PISC II)

International Nuclear Information System (INIS)

Curtis, G.J.

1987-01-01

In 1980-81, Harwell developed a mini-computer controlled multi-probe defect detection and sizing system based on the ultrasonic time-of-flight/diffraction principle introduced by Silk. This system proved to be capable of fully automatic data collection from the PWR girth-weld simulation Plates 1 and 2 in the Defect Detection Trials of 1981-82. The speed of collection and subsequent analysis was such that a report on the defects found could be filed within 48 hours. The mode of operation adopted simulated minimum time of access to the defects, and was intended to define that dimension of a defect which has greatest significance, i.e. the through-thickness dimension. In 1984, for the PISC II Trial, the approach adopted changed to emphasize the three-dimensional location and sizing capabilities of the time-of-flight/diffraction method. Data collection and analysis became highly interactive and the mode of operation simulated NDE at the manufacturing stage of a pressure vessel. The purpose of this paper is to indicate the defect through-thickness sizing capability of TOFD achieved in the 1981-82 Defect Detection Trials and the defect mapping capability achieved in the 1984 PISC II Trial

Combined X-ray and neutron fibre diffraction studies of biological and synthetic polymers

International Nuclear Information System (INIS)

Parrot, I.M.; Urban, V.; Gardner, K.H.; Forsyth, V.T.

2005-01-01

The fibrous state is a natural one for polymer molecules which tend to assume regular helical conformations rather than the globular structures characteristic of many proteins. Fibre diffraction therefore has broad application to the study of a wide range of biological and synthetic polymers. The purpose of this paper is to illustrate the general scope of the method and in particular to demonstrate the impact of a combined approach involving both X-ray and neutron diffraction methods. While the flux of modern X-ray synchrotron radiation sources allows high quality datasets to be recorded with good resolution within a very short space of time, neutron studies can provide unique information through the ability to locate hydrogen or deuterium atoms that are often difficult or impossible to locate using X-ray methods. Furthermore, neutron fibre diffraction methods can, through the ability to selectively label specific parts of a structure, be used to highlight novel aspects of polymer structure that can not be studied using X-rays. Two examples are given. The first describes X-ray and neutron diffraction studies of conformational transitions in DNA. The second describes structural studies of the synthetic high-performance polymer poly(p-phenylene terephthalamide) (PPTA), known commercially as Kevlar[reg] or Twaron[reg

Combined X-ray and neutron fibre diffraction studies of biological and synthetic polymers.

Energy Technology Data Exchange (ETDEWEB)

Parrot, I. M. [Institut Laue-Langevin (ILL); Urban, Volker S [ORNL; Gardner, K. H. [DuPont Experimental Station; Forsyth, V. T. [Institut Laue Langevin and Keele University

2005-04-01

The fibrous state is a natural one for polymer molecules which tend to assume regular helical conformations rather than the globular structures characteristic of many proteins. Fibre diffraction therefore has broad application to the study of a wide range of biological and synthetic polymers. The purpose of this paper is to illustrate the general scope of the method and in particular to demonstrate the impact of a combined approach involving both X-ray and neutron diffraction methods. While the flux of modern X-ray synchrotron radiation sources allows high quality datasets to be recorded with good resolution within a very short space of time, neutron studies can provide unique information through the ability to locate hydrogen or deuterium atoms that are often difficult or impossible to locate using X-ray methods. Furthermore, neutron fibre diffraction methods can, through the ability to selectively label specific parts of a structure, be used to highlight novel aspects of polymer structure that can not be studied using X-rays. Two examples are given. The first describes X-ray and neutron diffraction studies of conformational transitions in DNA. The second describes structural studies of the synthetic high-performance polymer poly(p-phenylene terephthalamide) (PPTA), known commercially as Kevlar{reg_sign} or Twaron{reg_sign}.

Combined X-ray and neutron fibre diffraction studies of biological and synthetic polymers

Science.gov (United States)

Parrot, I. M.; Urban, V.; Gardner, K. H.; Forsyth, V. T.

2005-08-01

The fibrous state is a natural one for polymer molecules which tend to assume regular helical conformations rather than the globular structures characteristic of many proteins. Fibre diffraction therefore has broad application to the study of a wide range of biological and synthetic polymers. The purpose of this paper is to illustrate the general scope of the method and in particular to demonstrate the impact of a combined approach involving both X-ray and neutron diffraction methods. While the flux of modern X-ray synchrotron radiation sources allows high quality datasets to be recorded with good resolution within a very short space of time, neutron studies can provide unique information through the ability to locate hydrogen or deuterium atoms that are often difficult or impossible to locate using X-ray methods. Furthermore, neutron fibre diffraction methods can, through the ability to selectively label specific parts of a structure, be used to highlight novel aspects of polymer structure that can not be studied using X-rays. Two examples are given. The first describes X-ray and neutron diffraction studies of conformational transitions in DNA. The second describes structural studies of the synthetic high-performance polymer poly(p-phenylene terephthalamide) (PPTA), known commercially as Kevlar® or Twaron®.

Combined X-ray and neutron fibre diffraction studies of biological and synthetic polymers

Energy Technology Data Exchange (ETDEWEB)

Parrot, I.M. [Institut Laue Langevin, 6 Rue Jules Horowitz, 38042 Grenoble Cedex 9 (France); Institute of Science and Technology in Medicine, Keele University Medical School, Staffordshire ST4 7QB (United Kingdom); Urban, V. [Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6100 (United States); Gardner, K.H. [Department of Materials Science and Engineering University of Delaware, Newark, DE 19719 (United States); Forsyth, V.T. [Institut Laue Langevin, 6 Rue Jules Horowitz, 38042 Grenoble Cedex 9 (France) and Institute of Science and Technology in Medicine, Keele University Medical School, Staffordshire ST4 7QB (United Kingdom)]. E-mail: tforsyth@ill.fr

2005-08-15

The fibrous state is a natural one for polymer molecules which tend to assume regular helical conformations rather than the globular structures characteristic of many proteins. Fibre diffraction therefore has broad application to the study of a wide range of biological and synthetic polymers. The purpose of this paper is to illustrate the general scope of the method and in particular to demonstrate the impact of a combined approach involving both X-ray and neutron diffraction methods. While the flux of modern X-ray synchrotron radiation sources allows high quality datasets to be recorded with good resolution within a very short space of time, neutron studies can provide unique information through the ability to locate hydrogen or deuterium atoms that are often difficult or impossible to locate using X-ray methods. Furthermore, neutron fibre diffraction methods can, through the ability to selectively label specific parts of a structure, be used to highlight novel aspects of polymer structure that can not be studied using X-rays. Two examples are given. The first describes X-ray and neutron diffraction studies of conformational transitions in DNA. The second describes structural studies of the synthetic high-performance polymer poly(p-phenylene terephthalamide) (PPTA), known commercially as Kevlar[reg] or Twaron[reg].

DNA hydration studied by neutron fiber diffraction

Energy Technology Data Exchange (ETDEWEB)

Fuller, W.; Forsyth, V.T.; Mahendrasingam, A.; Langan, P.; Pigram, W.J. [Keele Univ. (United Kingdom)] [and others

1994-12-31

The development of neutron high angle fiber diffraction to investigate the location of water around the deoxyribonucleic acid (DNA) double-helix is described. The power of the technique is illustrated by its application to the D and A conformations of DNA using the single crystal diffractometer, D19, at the Institute Laue-Langevin, Grenoble and the time of flight diffractometer, SXD, at the Rutherford Appleton ISIS Spallation Neutron Source. These studies show the existence of bound water closely associated with the DNA. The patterns of hydration in these two DNA conformations are quite distinct and are compared to those observed in X-ray single crystal studies of two-stranded oligodeoxynucleotides. Information on the location of water around the DNA double-helix from the neutron fiber diffraction studies is combined with that on the location of alkali metal cations from complementary X-ray high angle fiber diffraction studies at the Daresbury Laboratory SRS using synchrotron radiation. These analyses emphasize the importance of viewing DNA, water and ions as a single system with specific interactions between the three components and provide a basis for understanding the effect of changes in the concentration of water and ions in inducing conformations] transitions in the DNA double-helix.

DNA hydration studied by neutron fiber diffraction

International Nuclear Information System (INIS)

Fuller, W.; Forsyth, V.T.; Mahendrasingam, A.; Langan, P.; Pigram, W.J.

1994-01-01

The development of neutron high angle fiber diffraction to investigate the location of water around the deoxyribonucleic acid (DNA) double-helix is described. The power of the technique is illustrated by its application to the D and A conformations of DNA using the single crystal diffractometer, D19, at the Institute Laue-Langevin, Grenoble and the time of flight diffractometer, SXD, at the Rutherford Appleton ISIS Spallation Neutron Source. These studies show the existence of bound water closely associated with the DNA. The patterns of hydration in these two DNA conformations are quite distinct and are compared to those observed in X-ray single crystal studies of two-stranded oligodeoxynucleotides. Information on the location of water around the DNA double-helix from the neutron fiber diffraction studies is combined with that on the location of alkali metal cations from complementary X-ray high angle fiber diffraction studies at the Daresbury Laboratory SRS using synchrotron radiation. These analyses emphasize the importance of viewing DNA, water and ions as a single system with specific interactions between the three components and provide a basis for understanding the effect of changes in the concentration of water and ions in inducing conformations] transitions in the DNA double-helix

Six-axis multi-anvil press for high-pressure, high-temperature neutron diffraction experiments

Energy Technology Data Exchange (ETDEWEB)

Sano-Furukawa, A., E-mail: sano.asami@jaea.go.jp; Hattori, T. [Quantum Beam Science Center, Japan Atomic Energy Agency, Ibaraki 319-1195 (Japan); J-PARC Center, Japan Atomic Energy Agency, Ibaraki 319-1195 (Japan); Arima, H. [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Yamada, A. [The University of Shiga Prefecture, Shiga 522-8533 (Japan); Tabata, S.; Kondo, M.; Nakamura, A. [Sumitomo Heavy Industries Co., Ltd., Ehime 792-0001 (Japan); Kagi, H.; Yagi, T. [Geochemical Research Center, Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan)

2014-11-15

We developed a six-axis multi-anvil press, ATSUHIME, for high-pressure and high-temperature in situ time-of-flight neutron powder diffraction experiments. The press has six orthogonally oriented hydraulic rams that operate individually to compress a cubic sample assembly. Experiments indicate that the press can generate pressures up to 9.3 GPa and temperatures up to 2000 K using a 6-6-type cell assembly, with available sample volume of about 50 mm{sup 3}. Using a 6-8-type cell assembly, the available conditions expand to 16 GPa and 1273 K. Because the six-axis press has no guide blocks, there is sufficient space around the sample to use the aperture for diffraction and place an incident slit, radial collimators, and a neutron imaging camera close to the sample. Combination of the six-axis press and the collimation devices realized high-quality diffraction pattern with no contamination from the heater or the sample container surrounding the sample. This press constitutes a new tool for using neutron diffraction to study the structures of crystals and liquids under high pressures and temperatures.

Crystallization Kinetics of Nanocrystalline Materials by Combined X-ray Diffraction and Differential Scanning Calorimetry Experiments

Czech Academy of Sciences Publication Activity Database

Gil-González, E.; Perejón, A.; Sánchez-Jiménez, P. E.; Medina-Carrasco, S.; Kupčík, Jaroslav; Šubrt, Jan; Criado, J. M.; Pérez-Maqueda, L. A.

2018-01-01

Roč. 18, č. 5 (2018), s. 3107-3116 ISSN 1528-7483 Institutional support: RVO:61388980 Keywords : nanocrysalline alloys * combined X ray diffraction * crystallization kinetics Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 4.055, year: 2016

Time-of-flight pulsed neutron diffraction of molten salts

Energy Technology Data Exchange (ETDEWEB)

Fukushima, Y; Misawa, M; Suzuki, K [Tohoku Univ., Sendai (Japan). Research Inst. for Iron, Steel and Other Metals

1975-06-01

In this work, the pulsed neutron diffraction of molten alkali metal nitrate and bismuth trihalide was measured by the time-of-flight method. An electron linear accelerator was used as the pulsed neutron source. All the measurements were carried out with the T-O-F neutron diffractometer installed on the 300 MeV electron lineac. Molten NaNO/sub 3/ and RbNO/sub 3/ were adopted as the samples for alkali metal nitrate. The measurement is in progress for KNO/sub 3/ and LiNO/sub 3/. As the first step of the study on bismuth-bismuth trihalide system, the temperature dependence of structure factors was observed for BiCl/sub 3/, BiBr/sub 3/ and BiI/sub 3/ in the liquid state. The structure factors Sm(Q) for molten NaNO/sub 3/ at 340/sup 0/C and RbNO/sub 3/ at 350/sup 0/C were obtained, and the form factor F/sub 1/(Q) for single NO/sub 3//sup -/ radical with equilateral triangle structure was calculated. In case of molten NaNO/sub 3/, the first peak of Sm(Q) is simply smooth and a small hump can be observed in the neighbourhood of the first minimum Q position. The first peak of Sm(Q) for molten RbNO/sub 3/ is divided into two peaks, whereas a hump at the first minimum becomes big, and shifts to the low Q side of the second peak. The size of the NO/sub 3//sup -/ radical in molten NaNO/sub 3/ is a little smaller than that in molten RbNO/sub 3/. The values of the bond length in the NO/sub 3//sup -/ radical are summarized for crystal state and liquid state. The temperature dependence of the structure factor S(Q) was observed for BiCl/sub 3/, BiBr/sub 3/ and BiI/sub 3/, and shown in a figure.

Photon-counting-based diffraction phase microscopy combined with single-pixel imaging

Science.gov (United States)

Shibuya, Kyuki; Araki, Hiroyuki; Iwata, Tetsuo

2018-04-01

We propose a photon-counting (PC)-based quantitative-phase imaging (QPI) method for use in diffraction phase microscopy (DPM) that is combined with a single-pixel imaging (SPI) scheme (PC-SPI-DPM). This combination of DPM with the SPI scheme overcomes a low optical throughput problem that has occasionally prevented us from obtaining quantitative-phase images in DPM through use of a high-sensitivity single-channel photodetector such as a photomultiplier tube (PMT). The introduction of a PMT allowed us to perform PC with ease and thus solved a dynamic range problem that was inherent to SPI. As a proof-of-principle experiment, we performed a comparison study of analogue-based SPI-DPM and PC-SPI-DPM for a 125-nm-thick indium tin oxide (ITO) layer coated on a silica glass substrate. We discuss the basic performance of the method and potential future modifications of the proposed system.

Lattice strain measurements on sandstones under load using neutron diffraction

Science.gov (United States)

Frischbutter, A.; Neov, D.; Scheffzük, Ch.; Vrána, M.; Walther, K.

2000-11-01

Neutron diffraction methods (both time-of-flight- and angle-dispersive diffraction) are applied to intracrystalline strain measurements on geological samples undergoing uniaxial increasing compressional load. The experiments were carried out on Cretaceous sandstones from the Elbezone (East Germany), consisting of >95% quartz which are bedded but without crystallographic preferred orientation of quartz. From the stress-strain relation the Young's modulus for our quartz sample was determined to be (72.2±2.9) GPa using results of the neutron time-of-flight method. The influence of different kinds of bedding in sandstones (laminated and convolute bedding) could be determined. We observed differences of factor 2 (convolute bedding) and 3 (laminated bedding) for the elastic stiffness, determined with angle dispersive neutron diffraction (crystallographic strain) and with strain gauges (mechanical strain). The data indicate which geological conditions may influence the stress-strain behaviour of geological materials. The influence of bedding on the stress-strain behaviour of a laminated bedded sandstone was indicated by direct residual stress measurements using neutron time-of-flight diffraction. The measurements were carried out six days after unloading the sample. Residual strain was measured for three positions from the centre to the periphery and within two radial directions of the cylinder. We observed that residual strain changes from extension to compression in a different manner for two perpendicular directions of the bedding plane.

Five years of testing using the simi-automated ultrasonic time of flight diffraction system

International Nuclear Information System (INIS)

Webber, S.A.

2002-01-01

This paper provides a brief description of the Time of Flight Diffraction (TOFD) test system and also describes a couple of case histories where the system has been successfully applied. The T.O.F.D. system has been contrasted with the conventional manual ultrasonic technique. Whilst the T.O.F.D. system has proven potential, and is without doubt a valuable tool that will continue to gain market share in the inspection industry, conventional manual ultrasonics still has its part to play and will survive for some time to come. One of the outstanding issues facing the T.O.F.D. systems is the question of acceptance testing which is still the predominant convention specified in most standards. Training for a T.O.F.D. system technician is particularly important and the author suggests there are more traps for the unwary than with the conventional manual ultrasonic systems. The overall judgement of the T.O.F.D. system is that it is a most welcome and powerful tool in the hands of the right operator and will do much to boost the prominence of Non-Destructive Testing

Crystal structure relation between tetragonal and orthorhombic CsAlD{sub 4}: DFT and time-of-flight neutron powder diffraction studies

Energy Technology Data Exchange (ETDEWEB)

Bernert, Thomas; Krech, Daniel; Felderhoff, Michael; Weidenthaler, Claudia [Department of Heterogeneous Catalysis, Max-Planck-Institut fuer Kohlenforschung, Muelheim/Ruhr (Germany); Kockelmann, Winfried [Rutherford Appleton Laboratory, Harwell Oxford, Didcot (United Kingdom); Frankcombe, Terry J. [Research School of Chemistry, The Australian National University, Canberra, ACT (Australia); School of Physical, Environmental and Mathematic Sciences, The University of New South Wales, Canberra, ACT (Australia)

2015-11-15

The crystal structures of orthorhombic and tetragonal CsAlD{sub 4} were refined from time-of-flight neutron powder diffraction data starting from atomic positions predicted from DFT calculations. The earlier proposed crystal structure of orthorhombic CsAlH{sub 4} is confirmed. For tetragonal CsAlH{sub 4}, DFT calculations predicted a crystal structure in I4{sub 1}/amd as potential minimum structure, while from neutron diffraction studies of CsAlD{sub 4} best refinement is obtained for a disordered structure in the space group I4{sub 1}/a, with a = 5.67231(9) Aa, c = 14.2823(5) Aa. While the caesium atoms are located on the Wyckoff position 4b and aluminium at Wyckoff position 4a, there are two distinct deuterium positions at the Wyckoff position 16f with occupancies of 50 % each. From this structure, the previously reported phase transition between the orthorhombic and tetragonal polymorphs could be explained. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Combined inclusive diffractive cross sections measured with forward proton spectrometers in deep inelastic ep scattering at HERA

CERN Document Server

Aaron, F.D.; Abt, I.; Adamczyk, L.; Adamus, M.; Aggarwal, R.; Alexa, C.; Andreev, V.; Antonelli, S.; Antonioli, P.; Antonov, A.; Arneodo, M.; Arslan, O.; Aushev, V.; Aushev, Y.; Bachynska, O.; Backovic, S.; Baghdasaryan, A.; Baghdasaryan, S.; Bamberger, A.; Barakbaev, A.N.; Barbagli, G.; Bari, G.; Barreiro, F.; Barrelet, E.; Bartel, W.; Bartosik, N.; Bartsch, D.; Basile, M.; Begzsuren, K.; Behnke, O.; Behr, J.; Behrens, U.; Bellagamba, L.; Belousov, A.; Belov, P.; Bertolin, A.; Bhadra, S.; Bindi, M.; Bizot, J.C.; Blohm, C.; Bokhonov, V.; Bondarenko, K.; Boos, E.G.; Borras, K.; Boscherini, D.; Bot, D.; Boudry, V.; Bozovic-Jelisavcic, I.; Bold, T.; Brummer, N.; Bracinik, J.; Brandt, G.; Brinkmann, M.; Brisson, V.; Britzger, D.; Brock, I.; Brownson, E.; Brugnera, R.; Bruncko, D.; Bruni, A.; Bruni, G.; Brzozowska, B.; Bunyatyan, A.; Bussey, P.J.; Bylinkin, A.; Bylsma, B.; Bystritskaya, L.; Caldwell, A.; Campbell, A.J.; Cantun Avila, K.B.; Capua, M.; Carlin, R.; Catterall, C.D.; Ceccopieri, F.; Cerny, K.; Cerny, V.; Chekanov, S.; Chekelian, V.; Chwastowski, J.; Ciborowski, J.; Ciesielski, R.; Cifarelli, L.; Cindolo, F.; Contin, A.; Contreras, J.G.; Cooper-Sarkar, A.M.; Coppola, N.; Corradi, M.; Corriveau, F.; Costa, M.; Coughlan, J.A.; Cvach, J.; D'Agostini, G.; Dainton, J.B.; Dal Corso, F.; Daum, K.; Delcourt, B.; Delvax, J.; Dementiev, R.K.; Derrick, M.; Devenish, R.C.E.; De Pasquale, S.; De Wolf, E.A.; del Peso, J.; Diaconu, C.; Dobre, M.; Dobur, D.; Dodonov, V.; Dolgoshein, B.A.; Dolinska, G.; Dossanov, A.; Doyle, A.T.; Drugakov, V.; Dubak, A.; Durkin, L.S.; Dusini, S.; Eckerlin, G.; Egli, S.; Eisenberg, Y.; Eliseev, A.; Elsen, E.; Ermolov, P.F.; Eskreys, A.; Fang, S.; Favart, L.; Fazio, S.; Fedotov, A.; Felst, R.; Feltesse, J.; Ferencei, J.; Ferrando, J.; Ferrero, M.I.; Figiel, J.; Fischer, D.J.; Fleischer, M.; Fomenko, A.; Forrest, M.; Foster, B.; Gabathuler, E.; Gach, G.; Galas, A.; Gallo, E.; Garfagnini, A.; Gayler, J.; Geiser, A.; Ghazaryan, S.; Gialas, I.; Gizhko, A.; Gladilin, L.K.; Gladkov, D.; Glasman, C.; Glazov, A.; Goerlich, L.; Gogitidze, N.; Gogota, O.; Golubkov, Yu.A.; Gottlicher, P.; Gouzevitch, M.; Grab, C.; Grabowska-Bold, I.; Grebenyuk, A.; Grebenyuk, J.; Greenshaw, T.; Gregor, I.; Grigorescu, G.; Grindhammer, G.; Grzelak, G.; Gueta, O.; Guzik, M.; Gwenlan, C.; Huttmann, A.; Haas, T.; Habib, S.; Haidt, D.; Hain, W.; Hamatsu, R.; Hart, J.C.; Hartmann, H.; Hartner, G.; Henderson, R.C.W.; Hennekemper, E.; Henschel, H.; Herbst, M.; Herrera, G.; Hildebrandt, M.; Hilger, E.; Hiller, K.H.; Hladky, J.; Hochman, D.; Hoffmann, D.; Hori, R.; Horisberger, R.; Hreus, T.; Huber, F.; Ibrahim, Z.A.; Iga, Y.; Ingbir, R.; Ishitsuka, M.; Jacquet, M.; Jakob, H.P.; Janssen, X.; Januschek, F.; Jones, T.W.; Jonsson, L.; Jungst, M.; Jung, H.; Kadenko, I.; Kahle, B.; Kananov, S.; Kanno, T.; Kapichine, M.; Karshon, U.; Karstens, F.; Katkov, I.I.; Kaur, P.; Kaur, M.; Kenyon, I.R.; Keramidas, A.; Khein, L.A.; Kiesling, C.; Kim, J.Y.; Kisielewska, D.; Kitamura, S.; Klanner, R.; Klein, M.; Klein, U.; Kleinwort, C.; Koffeman, E.; Kogler, R.; Kondrashova, N.; Kononenko, O.; Kooijman, P.; Korol, Ie.; Korzhavina, I.A.; Kostka, P.; Kotanski, A.; Kotz, U.; Kowalski, H.; Kramer, M.; Kretzschmar, J.; Kruger, K.; Kuprash, O.; Kuze, M.; Landon, M.P.J.; Lange, W.; Lastovicka-Medin, G.; Laycock, P.; Lebedev, A.; Lee, A.; Lendermann, V.; Levchenko, B.B.; Levonian, S.; Levy, A.; Libov, V.; Limentani, S.; Ling, T.Y.; Lipka, K.; Lisovyi, M.; List, B.; List, J.; Lobodzinska, E.; Lobodzinski, B.; Lohmann, W.; Lohr, B.; Lohrmann, E.; Long, K.R.; Longhin, A.; Lontkovskyi, D.; Lopez-Fernandez, R.; Lubimov, V.; Lukina, O.Yu.; Maeda, J.; Magill, S.; Makarenko, I.; Malinovski, E.; Malka, J.; Mankel, R.; Margotti, A.; Marini, G.; Martin, J.F.; Martyn, H.U.; Mastroberardino, A.; Mattingly, M.C.K.; Maxfield, S.J.; Mehta, A.; Melzer-Pellmann, I.A.; Mergelmeyer, S.; Meyer, A.B.; Meyer, H.; Meyer, J.; Miglioranzi, S.; Mikocki, S.; Milcewicz-Mika, I.; Idris, F.Mohamad; Monaco, V.; Montanari, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Morris, J.D.; Mujkic, K.; Muller, K.; Musgrave, B.; Nagano, K.; Namsoo, T.; Nania, R.; Naumann, Th.; Newman, P.R.; Niebuhr, C.; Nigro, A.; Nikitin, D.; Ning, Y.; Nobe, T.; Notz, D.; Nowak, G.; Nowak, K.; Nowak, R.J.; Nuncio-Quiroz, A.E.; Oh, B.Y.; Okazaki, N.; Olkiewicz, K.; Olsson, J.E.; Onishchuk, Yu.; Ozerov, D.; Pahl, P.; Palichik, V.; Pandurovic, M.; Papageorgiu, K.; Parenti, A.; Pascaud, C.; Patel, G.D.; Paul, E.; Pawlak, J.M.; Pawlik, B.; Pelfer, P.G.; Pellegrino, A.; Perez, E.; Perlanski, W.; Perrey, H.; Petrukhin, A.; Picuric, I.; Piotrzkowski, K.; Pirumov, H.; Pitzl, D.; Placakyte, R.; Plucinski, P.; Pokorny, B.; Pokrovskiy, N.S.; Polifka, R.; Polini, A.; Povh, B.; Proskuryakov, A.S.; Przybycien, M.; Radescu, V.; Raicevic, N.; Raval, A.; Ravdandorj, T.; Reeder, D.D.; Reimer, P.; Reisert, B.; Ren, Z.; Repond, J.; Ri, Y.D.; Rizvi, E.; Robertson, A.; Robmann, P.; Roloff, P.; Roosen, R.; Rostovtsev, A.; Rotaru, M.; Rubinsky, I.; Ruiz Tabasco, J.E.; Rusakov, S.; Ruspa, M.; Sacchi, R.; Salek, D.; Samson, U.; Sankey, D.P.C.; Sartorelli, G.; Sauter, M.; Sauvan, E.; Savin, A.A.; Saxon, D.H.; Schioppa, M.; Schlenstedt, S.; Schleper, P.; Schmidke, W.B.; Schmitt, S.; Schneekloth, U.; Schoeffel, L.; Schonberg, V.; Schoning, A.; Schorner-Sadenius, T.; Schultz-Coulon, H.C.; Schwartz, J.; Sciulli, F.; Sefkow, F.; Shcheglova, L.M.; Shehzadi, R.; Shimizu, S.; Shtarkov, L.N.; Shushkevich, S.; Singh, I.; Skillicorn, I.O.; Slominski, W.; Sloan, T.; Smith, W.H.; Sola, V.; Solano, A.; Soloviev, Y.; Son, D.; Sopicki, P.; Sosnovtsev, V.; South, D.; Spaskov, V.; Specka, A.; Spiridonov, A.; Stadie, H.; Stanco, L.; Staykova, Z.; Steder, M.; Stefaniuk, N.; Stella, B.; Stern, A.; Stewart, T.P.; Stifutkin, A.; Stoicea, G.; Stopa, P.; Straumann, U.; Suchkov, S.; Susinno, G.; Suszycki, L.; Sykora, T.; Sztuk-Dambietz, J.; Szuba, J.; Szuba, D.; Tapper, A.D.; Tassi, E.; Terron, J.; Theedt, T.; Thompson, P.D.; Tiecke, H.; Tokushuku, K.; Tomaszewska, J.; Tran, T.H.; Traynor, D.; Truol, P.; Trusov, V.; Tsakov, I.; Tseepeldorj, B.; Tsurugai, T.; Turcato, M.; Turkot, O.; Turnau, J.; Tymieniecka, T.; Vazquez, M.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Vazdik, Y.; Verbytskyi, A.; Viazlo, O.; Vlasov, N.N.; Walczak, R.; Wan Abdullah, W.A.T.; Wegener, D.; Whitmore, J.J.; Wichmann, K.; Wiggers, L.; Wing, M.; Wlasenko, M.; Wolf, G.; Wolfe, H.; Wrona, K.; Wunsch, E.; Yagues-Molina, A.G.; Yamada, S.; Yamazaki, Y.; Yoshida, R.; Youngman, C.; Zabiegalov, O.; Zacek, J.; Zalesak, J.; Zawiejski, L.; Zenaiev, O.; Zeuner, W.; Zhang, Z.; Zhautykov, B.O.; Zhmak, N.; Zhokin, A.; Zichichi, A.; Zlebcik, R.; Zohrabyan, H.; Zolkapli, Z.; Zomer, F.; Zotkin, D.S.; Zarnecki, A.F.

2012-10-10

A combination of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA is presented. The analysis uses samples of diffractive deep inelastic ep scattering data at a centre-of-mass energy sqrt(s) = 318 GeV where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account, resulting in an improved precision of the cross section measurement which reaches 6% for the most precise points. The combined data cover the range 2.5 < Q2 < 200 GeV2 in photon virtuality, 0.00035 < xIP < 0.09 in proton fractional momentum loss, 0.09 < |t| < 0.55 GeV2 in squared four-momentum transfer at the proton vertex and 0.0018 < beta < 0.816 in beta = x/xIP, where x is the Bjorken scaling variable.

Combined inclusive diffractive cross sections measured with foreward proton spectrometers in deep inelastic ep scattering at HERA

Energy Technology Data Exchange (ETDEWEB)

Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Abramowicz, H. [Tel Aviv Univ. (Israel). School of Physics; Max Planck Institute for Physics, Munich (Germany); Abt, I. [Max Planck Institute for Physics, Munich (DE)] (and others)

2012-07-15

A combination of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA is presented. The analysis uses samples of diffractive deep inelastic ep scattering data at a centre-of-mass energy {radical}(s)=318 GeV where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account, resulting in an improved precision of the cross section measurement which reaches 6% for the most precise points. The combined data cover the range 2.5

Monte Carlo study of particle production in diffractive proton-proton collisions at √(s) = 13 TeV with the very forward detector combined with central information

Energy Technology Data Exchange (ETDEWEB)

Zhou, Qi-Dong [Nagoya University, Institute for Space-Earth Environmental Research, Nagoya (Japan); Itow, Yoshitaka; Sako, Takashi [Nagoya University, Institute for Space-Earth Environmental Research, Nagoya (Japan); Nagoya University, Kobayashi-Maskawa Institute, Nagoya (Japan); Menjo, Hiroaki [Nagoya University, Graduate School of Science, Nagoya (Japan)

2017-04-15

Very forward (VF) detectors in hadron colliders, having unique sensitivity to diffractive processes, can be a powerful tool for studying diffractive dissociation by combining them with central detectors. Several Monte Carlo simulation samples in p-p collisions at √(s) = 13 TeV were analyzed, and different nondiffractive and diffractive contributions were clarified through differential cross sections of forward neutral particles. Diffraction selection criteria in the VF-triggered-event samples were determined by using the central track information. The corresponding selection applicable in real experiments has ∼ 100% purity and 30-70% efficiency. Consequently, the central information enables classification of the forward productions into diffraction and nondiffraction categories; in particular, most of the surviving events from the selection belong to low-mass diffraction events at log{sub 10}(ξ{sub x}) < -5.5. Therefore, the combined method can uniquely access the low-mass diffraction regime experimentally. (orig.)

Combining operando synchrotron X-ray tomographic microscopy and scanning X-ray diffraction to study lithium ion batteries

Science.gov (United States)

Pietsch, Patrick; Hess, Michael; Ludwig, Wolfgang; Eller, Jens; Wood, Vanessa

2016-06-01

We present an operando study of a lithium ion battery combining scanning X-ray diffraction (SXRD) and synchrotron radiation X-ray tomographic microscopy (SRXTM) simultaneously for the first time. This combination of techniques facilitates the investigation of dynamic processes in lithium ion batteries containing amorphous and/or weakly attenuating active materials. While amorphous materials pose a challenge for diffraction techniques, weakly attenuating material systems pose a challenge for attenuation-contrast tomography. Furthermore, combining SXRD and SRXTM can be used to correlate processes occurring at the atomic level in the crystal lattices of the active materials with those at the scale of electrode microstructure. To demonstrate the benefits of this approach, we investigate a silicon powder electrode in lithium metal half-cell configuration. Combining SXRD and SRXTM, we are able to (i) quantify the dissolution of the metallic lithium electrode and the expansion of the silicon electrode, (ii) better understand the formation of the Li15Si4 phase, and (iii) non-invasively probe kinetic limitations within the silicon electrode. A simple model based on the 1D diffusion equation allows us to qualitatively understand the observed kinetics and demonstrates why high-capacity electrodes are more prone to inhomogeneous lithiation reactions.

Combining operando synchrotron X-ray tomographic microscopy and scanning X-ray diffraction to study lithium ion batteries

Science.gov (United States)

Pietsch, Patrick; Hess, Michael; Ludwig, Wolfgang; Eller, Jens; Wood, Vanessa

2016-01-01

We present an operando study of a lithium ion battery combining scanning X-ray diffraction (SXRD) and synchrotron radiation X-ray tomographic microscopy (SRXTM) simultaneously for the first time. This combination of techniques facilitates the investigation of dynamic processes in lithium ion batteries containing amorphous and/or weakly attenuating active materials. While amorphous materials pose a challenge for diffraction techniques, weakly attenuating material systems pose a challenge for attenuation-contrast tomography. Furthermore, combining SXRD and SRXTM can be used to correlate processes occurring at the atomic level in the crystal lattices of the active materials with those at the scale of electrode microstructure. To demonstrate the benefits of this approach, we investigate a silicon powder electrode in lithium metal half-cell configuration. Combining SXRD and SRXTM, we are able to (i) quantify the dissolution of the metallic lithium electrode and the expansion of the silicon electrode, (ii) better understand the formation of the Li15Si4 phase, and (iii) non-invasively probe kinetic limitations within the silicon electrode. A simple model based on the 1D diffusion equation allows us to qualitatively understand the observed kinetics and demonstrates why high-capacity electrodes are more prone to inhomogeneous lithiation reactions. PMID:27324109

Diffraction and single-crystal elastic constants of Inconel 625 at room and elevated temperatures determined by neutron diffraction

International Nuclear Information System (INIS)

Wang, Zhuqing; Stoica, Alexandru D.; Ma, Dong; Beese, Allison M.

2016-01-01

In this work, diffraction and single-crystal elastic constants of Inconel 625 have been determined by means of in situ loading at room and elevated temperatures using time-of-flight neutron diffraction. Theoretical models proposed by Voigt, Reuss, and Kroner were used to determine single-crystal elastic constants from measured diffraction elastic constants, with the Kroner model having the best ability to capture experimental data. The magnitude of single-crystal elastic moduli, computed from single-crystal elastic constants, decreases and the single crystal anisotropy increases as temperature increases, indicating the importance of texture in affecting macroscopic stress at elevated temperatures. The experimental data reported here are of great importance in understanding additive manufacturing of metallic components as: diffraction elastic constants are required for computing residual stresses from residual lattice strains measured using neutron diffraction, which can be used to validate thermomechanical models of additive manufacturing, while single-crystal elastic constants can be used in crystal plasticity modeling, for example, to understand mechanical deformation behavior of additively manufactured components.

Diffraction and single-crystal elastic constants of Inconel 625 at room and elevated temperatures determined by neutron diffraction

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhuqing [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 (United States); Stoica, Alexandru D. [Chemical and Engineering Materials Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Ma, Dong, E-mail: dongma@ornl.gov [Chemical and Engineering Materials Division, Neutron Sciences Directorate, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Beese, Allison M., E-mail: amb961@psu.edu [Department of Materials Science and Engineering, Pennsylvania State University, University Park, PA 16802 (United States)

2016-09-30

In this work, diffraction and single-crystal elastic constants of Inconel 625 have been determined by means of in situ loading at room and elevated temperatures using time-of-flight neutron diffraction. Theoretical models proposed by Voigt, Reuss, and Kroner were used to determine single-crystal elastic constants from measured diffraction elastic constants, with the Kroner model having the best ability to capture experimental data. The magnitude of single-crystal elastic moduli, computed from single-crystal elastic constants, decreases and the single crystal anisotropy increases as temperature increases, indicating the importance of texture in affecting macroscopic stress at elevated temperatures. The experimental data reported here are of great importance in understanding additive manufacturing of metallic components as: diffraction elastic constants are required for computing residual stresses from residual lattice strains measured using neutron diffraction, which can be used to validate thermomechanical models of additive manufacturing, while single-crystal elastic constants can be used in crystal plasticity modeling, for example, to understand mechanical deformation behavior of additively manufactured components.

Laboratory and In-Flight In-Situ X-ray Imaging and Scattering Facility for Materials, Biotechnology and Life Sciences

Science.gov (United States)

2003-01-01

We propose a multifunctional X-ray facility for the Materials, Biotechnology and Life Sciences Programs to visualize formation and behavior dynamics of materials, biomaterials, and living organisms, tissues and cells. The facility will combine X-ray topography, phase micro-imaging and scattering capabilities with sample units installed on the goniometer. This should allow, for the first time, to monitor under well defined conditions, in situ, in real time: creation of imperfections during growth of semiconductors, metal, dielectric and biomacromolecular crystals and films, high-precision diffraction from crystals within a wide range of temperatures and vapor, melt, solution conditions, internal morphology and changes in living organisms, tissues and cells, diffraction on biominerals, nanotubes and particles, radiation damage, also under controlled formation/life conditions. The system will include an ultrabright X-ray source, X-ray mirror, monochromator, image-recording unit, detectors, and multipurpose diffractometer that fully accommodate and integrate furnaces and samples with other experimental environments. The easily adjustable laboratory and flight versions will allow monitoring processes under terrestrial and microgravity conditions. The flight version can be made available using a microsource combined with multilayer or capillary optics.

Flight times to the heliopause using a combination of solar and radioisotope electric propulsion

Energy Technology Data Exchange (ETDEWEB)

Ohndorf, Andreas [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Wessling (Germany); Dachwald, Bernd [FH Univ. of Applied Sciences, Aachen (Germany); Seboldt, Wolfgang [DLR Deutsches Zentrum fuer Luft- und Raumfahrt e.V., Koeln (Germany); Loeb, Horst W.; Schartner, Karl-Heinz [Giessen Univ. (Germany)

2011-07-01

We investigate the interplanetary flight of a low-thrust space probe to the heliopause, located at a distance of about 200 AU from the Sun. Our goal was to reach this distance within the 25 years postulated by ESA for such a mission (which is less ambitious than the 15-year goal set by NASA). Contrary to solar sail concepts and combinations of ballistic and electrically propelled flight legs, we have investigated whether the set flight time limit could also be kept with a combination of solar-electric propulsion and a second, RTG-powered upper stage. The used ion engine type was the RIT-22 for the first stage and the RIT-10 for the second stage. Trajectory optimization was carried out with the low-thrust optimization program InTrance, which implements the method of Evolutionary Neurocontrol, using Artificial Neural Networks for spacecraft steering and Evolutionary Algorithms to optimize the Neural Networks' parameter set. Based on a parameter space study, in which the number of thrust units, the unit's specific impulse, and the relative size of the solar power generator were varied, we have chosen one configuration as reference. The transfer time of this reference configuration was 29.6 years and the fastest one, which is technically more challenging, still required 28.3 years. As all flight times of this parameter study were longer than 25 years, we further shortened the transfer time by applying a launcher-provided hyperbolic excess energy up to 49 km{sup 2}/s{sup 2}. The resulting minimal flight time for the reference configuration was then 27.8 years. The following, more precise optimization to a launch with the European Ariane 5 ECA rocket reduced the transfer time to 27.5 years. This is the fastest mission design of our study that is flexible enough to allow a launch every year. The inclusion of a fly-by at Jupiter finally resulted in a flight time of 23.8 years, which is below the set transfer-time limit. However, compared to the 27.5-year transfer

Explanation and observability of diffraction in time

International Nuclear Information System (INIS)

Torrontegui, E.; Muga, J. G.; Munoz, J.; Ban, Yue

2011-01-01

Diffraction in time (DIT) is a fundamental phenomenon in quantum dynamics due to time-dependent obstacles and slits. It is formally analogous to diffraction of light, and is expected to play an increasing role in the design of coherent matter wave sources, as in the atom laser, to analyze time-of-flight information and emission from ultrafast pulsed excitations, and in applications of coherent matter waves in integrated atom-optical circuits. We demonstrate that DIT emerges robustly in quantum waves emitted by an exponentially decaying source and provide a simple explanation of the phenomenon, as an interference of two characteristic velocities. This allows for its controllability and optimization.

Use of neutron diffraction and laser-induced plasma spectroscopy in integrated authentication methodologies of copper alloy artefacts

International Nuclear Information System (INIS)

Siano, S.; Bartol, L.; Mencaglia, A.A.; Agresti, J.; Miccio, M.

2009-01-01

The present study approaches the general problem of the authentication of copper alloy artefacts of art and historical interest using non-invasive analytical techniques. It aims to demonstrate that a suitable combination of time-of-flight neutron diffraction and laser-induced plasma spectroscopy in integrated multidisciplinary authentication methodologies can provide crucial data for discriminating between genuine archaeological objects and modern counterfeits. After introducing the methodology, which is dedicated in particular to copper alloy figurines of ancient style, two representative authentication case studies are discussed. The results of the work provide evidence that the combination of multiphase analysis using TOF-N D and elemental depth profiles provided by Lips makes it possible to solve most of the present authentication problems.

New opportunities for 3D materials science of polycrystalline materials at the micrometre lengthscale by combined use of X-ray diffraction and X-ray imaging

DEFF Research Database (Denmark)

Ludwig, W.; King, A.; Reischig, P.

2009-01-01

Non-destructive, three-dimensional (3D) characterization of the grain structure in mono-phase polycrystalline materials is an open challenge in material science. Recent advances in synchrotron based X-ray imaging and diffraction techniques offer interesting possibilities for mapping 3D grain shapes....... A recent extension of this methodology, termed X-ray diffraction contrast tomography (DCT), combines the principles of X-ray diffraction imaging, three-dimensional X-ray diffraction microscopy (3DXRD) and image reconstruction from projections. DCT provides simultaneous access to 3D grain shape...

Application of neutron diffraction in characterization of texture evolution during high-temperature creep in magnesium alloys

International Nuclear Information System (INIS)

Sediako, A.; Shook, S.; Vogel, S.; Sediako, D.

2010-01-01

A good combination of room-temperature and elevated temperature strength and ductility, good salt-spray corrosion resistance and excellent diecastability are frequently among the main considerations in development of a new magnesium alloy for automotive industry. Unfortunately, there has been much lesser effort in development of wrought-stock alloys for high temperature applications. Extrudability and high temperature performance of wrought material become important factors in an effort to develop new wrought alloys and processing technologies. This paper shows some results received in creep testing and studies of in-creep texture evolution for several wrought magnesium alloys developed for use in elevated- temperature applications. Along with others 'traditional' characterization techniques of metals' performance in high- temperature creep, neutron diffraction was employed in this study to analyze evolution of crystallographic texture during creep deformation. The paper compares two methods of texture analysis in neutron diffraction studies: based on monochromatic (reactor-source) beam and white neutron beam (time-of-flight method, synchrotron). The time-of-flight (TOF) spectrometer illuminates the sample with a non-filtered beam of neutrons and captures the readings with an encircled detector array. This provides a very fast and detailed picture of the crystallographic texture for the bulk of the sample. As the white beam retains all neutron wavelengths, it takes much less time to collect statistically-valid dataset for the diffraction pattern. On the other hand, the monochromatic beam setup includes a monochromatic crystal that filters out a specific wavelength. The diffracted beam is then captured by a much simpler neutron detector. This setup is more flexible, allowing for choosing various wavelengths (depending on the sample material) but obviously requiring more time for statistically viable data collection. These studies were performed using E3 neutron

Effects of gauge volume on pseudo-strain induced in strain measurement using time-of-flight neutron diffraction

International Nuclear Information System (INIS)

Suzuki, Hiroshi; Harjo, Stefanus; Abe, Jun; Xu, Pingguang; Aizawa, Kazuya; Akita, Koichi

2013-01-01

Spurious or pseudo-strains observed in time-of-flight (TOF) neutron diffraction due to neutron attenuation, surface-effects and a strain distribution within the gauge volume were investigated. Experiments were carried out on annealed and bent ferritic steel bars to test these effects. The most representative position in the gauge volume corresponds to the neutron-weighted center of gravity (ncog), which takes into account variations in intensity within the gauge volume due to neutron attenuation and/or absence of material in the gauge volume. The average strain in the gauge volume was observed to be weighted towards the ncog position but following an increase in the size of the gauge volume the weighted average strain was changed because of the change in the ncog position when a strain gradient appeared within the gauge volume. On the other hand, typical pseudo-strains, which are well known, did appear in through-surface strain measurements when the gauge volume was incompletely filled by the sample. Tensile pseudo-strains due to the surface-effect increased near the sample surface and exhibited a similar trend regardless of the size of the gauge volume, while the pseudo-strains increased faster for the smaller gauge volume. Furthermore, a pseudo-strain due to a change in the ncog position was observed even when the gauge volume was perfectly filled in the sample, and it increased with an increase in the size of the gauge volume. These pseudo-strains measured were much larger than those simulated by the conventional modeling, whereas they were simulated by taking into account an incident neutron beam divergence additionally in the model. Therefore, the incident divergence of the incident neutron beam must be carefully designed to avoid pseudo-strains in time-of-flight neutron diffractometry

Efficient generation of 3.9 W of diffraction-limited green light with spectrally combined tapered diode lasers

DEFF Research Database (Denmark)

Müller, André; Jensen, Ole Bjarlin; Andersen, Peter E.

We propose an efficient concept increasing the power of diode laser systems in the visible spectral range. In comparison with second harmonic generation of single emitters, spectral beam combining with subsequent sum-frequency generation enhances the available power significantly. Combining two...... 1060 nm tapered diode lasers, we achieve a 2.5-3.2 fold increase of green light with a maximum power of 3.9 Watts in a diffraction-limited beam. At this level, diode lasers have a high application potential, for example, within the biomedical field. In order to enhance the power even further, our...

Correlating Atom Probe Crystallographic Measurements with Transmission Kikuchi Diffraction Data.

Science.gov (United States)

Breen, Andrew J; Babinsky, Katharina; Day, Alec C; Eder, K; Oakman, Connor J; Trimby, Patrick W; Primig, Sophie; Cairney, Julie M; Ringer, Simon P

2017-04-01

Correlative microscopy approaches offer synergistic solutions to many research problems. One such combination, that has been studied in limited detail, is the use of atom probe tomography (APT) and transmission Kikuchi diffraction (TKD) on the same tip specimen. By combining these two powerful microscopy techniques, the microstructure of important engineering alloys can be studied in greater detail. For the first time, the accuracy of crystallographic measurements made using APT will be independently verified using TKD. Experimental data from two atom probe tips, one a nanocrystalline Al-0.5Ag alloy specimen collected on a straight flight-path atom probe and the other a high purity Mo specimen collected on a reflectron-fitted instrument, will be compared. We find that the average minimum misorientation angle, calculated from calibrated atom probe reconstructions with two different pole combinations, deviate 0.7° and 1.4°, respectively, from the TKD results. The type of atom probe and experimental conditions appear to have some impact on this accuracy and the reconstruction and measurement procedures are likely to contribute further to degradation in angular resolution. The challenges and implications of this correlative approach will also be discussed.

Design of combined magnetic field system for magnetic-bottle time-of-flight spectrometer

International Nuclear Information System (INIS)

Wang Chao; Tian Jinshou; Zhang Meizhi; Kang Yifan

2011-01-01

Based on the primary requirement for the magnetic field system in magnetic-bottle time-of-flight spectrometer, an appropriate combined inhomogeneous magnetic field system is designed. The inhomogeneous higher magnetic field part, with the highest field of 1.2 T, is produced by the combination of a permanent magnet and a pole piece with optimized shape. The magnet,known as NdFeB magnet,is one of rare earth permanent magnets in N52. The guiding uniform magnetic field of 1.0 x 10 -3 T is provided by solenoid, with length of 3 m and radius of 3 cm. The pitch between the pole piece and the near end of used solenoid is determined to be 5 cm, which can satisfy the actual engineering needs. (authors)

Stress distribution in mechanically surface treated Ti-2.5Cu determined by combining energy-dispersive synchrotron and neutron diffraction

International Nuclear Information System (INIS)

Maawad, E.; Brokmeier, H.-G.; Hofmann, M.; Genzel, Ch.; Wagner, L.

2010-01-01

Mechanical surface treatments such as shot peening (SP) or ball-burnishing (BB) induce plastic deformation close to the surface resulting in work-hardening and compressive residual stresses. It enhances the fatigue performance by retarding or even suppressing micro-crack growth from the surface into the interior. SP and BB were carried out on a solution heat treated (SHT) Ti-2.5Cu. The investigations of compressive and balancing tensile residual stresses need a combination of energy-dispersive synchrotron (ED) and neutron diffraction. Essential for the stress distribution is the stress state before surface treatments which was determined by neutron diffraction. Results show that the maximum compressive stress and its depth play an important role to improve the fatigue performance.

A new bridge technique for neutron tomography and diffraction measurements

International Nuclear Information System (INIS)

Burca, G.; James, J.A.; Kockelmann, W.; Fitzpatrick, M.E.; Zhang, S.Y.; Hovind, J.; Langh, R. van

2011-01-01

An attractive feature of neutron techniques is the ability to identify hidden materials and structures inside engineering components and objects of art and archaeology. Bearing this in mind we are investigating a new technique, 'Tomography Driven Diffraction' (TDD), that exploits tomography data to guide diffraction experiments on samples with complex structures and shapes. The technique can be used utilising combinations of individual tomography and diffraction instruments, such as NEUTRA (PSI, CH) and ENGIN-X (ISIS, UK), but is also suitable for new combined imaging and diffraction instruments such as the JEEP synchrotron engineering instrument (DIAMOND, UK) and the proposed IMAT neutron imaging and diffraction instrument (ISIS, UK).

Aging Enhances Indirect Flight Muscle Fiber Performance yet Decreases Flight Ability in Drosophila

Energy Technology Data Exchange (ETDEWEB)

Miller, Mark S.; Lekkas, Panagiotis; Braddock, Joan M.; Farman, Gerrie P.; Ballif, Bryan A.; Irving, Thomas C.; Maughan, David W.; Vigoreaux, Jim O. (IIT); (Vermont)

2008-10-02

We investigated the effects of aging on Drosophila melanogaster indirect flight muscle from the whole organism to the actomyosin cross-bridge. Median-aged (49-day-old) flies were flight impaired, had normal myofilament number and packing, barely longer sarcomeres, and slight mitochondrial deterioration compared with young (3-day-old) flies. Old (56-day-old) flies were unable to beat their wings, had deteriorated ultrastructure with severe mitochondrial damage, and their skinned fibers failed to activate with calcium. Small-amplitude sinusoidal length perturbation analysis showed median-aged indirect flight muscle fibers developed greater than twice the isometric force and power output of young fibers, yet cross-bridge kinetics were similar. Large increases in elastic and viscous moduli amplitude under active, passive, and rigor conditions suggest that median-aged fibers become stiffer longitudinally. Small-angle x-ray diffraction indicates that myosin heads move increasingly toward the thin filament with age, accounting for the increased transverse stiffness via cross-bridge formation. We propose that the observed protein composition changes in the connecting filaments, which anchor the thick filaments to the Z-disk, produce compensatory increases in longitudinal stiffness, isometric tension, power and actomyosin interaction in aging indirect flight muscle. We also speculate that a lack of MgATP due to damaged mitochondria accounts for the decreased flight performance.

Towards automated diffraction tomography: Part I-Data acquisition

International Nuclear Information System (INIS)

Kolb, U.; Gorelik, T.; Kuebel, C.; Otten, M.T.; Hubert, D.

2007-01-01

The ultimate aim of electron diffraction data collection for structure analysis is to sample the reciprocal space as accurately as possible to obtain a high-quality data set for crystal structure determination. Besides a more precise lattice parameter determination, fine sampling is expected to deliver superior data on reflection intensities, which is crucial for subsequent structure analysis. Traditionally, three-dimensional (3D) diffraction data are collected by manually tilting a crystal around a selected crystallographic axis and recording a set of diffraction patterns (a tilt series) at various crystallographic zones. In a second step, diffraction data from these zones are combined into a 3D data set and analyzed to yield the desired structure information. Data collection can also be performed automatically, with the recent advances in tomography acquisition providing a suitable basis. An experimental software module has been developed for the Tecnai microscope for such an automated diffraction pattern collection while tilting around the goniometer axis. The module combines STEM imaging with diffraction pattern acquisition in nanodiffraction mode. It allows automated recording of diffraction tilt series from nanoparticles with a size down to 5 nm

Atomic resolution three-dimensional electron diffraction microscopy

International Nuclear Information System (INIS)

Miao Jianwei; Ohsuna, Tetsu; Terasaki, Osamu; Hodgson, Keith O.; O'Keefe, Michael A.

2002-01-01

We report the development of a novel form of diffraction-based 3D microscopy to overcome resolution barriers inherent in high-resolution electron microscopy and tomography. By combining coherent electron diffraction with the oversampling phasing method, we show that the 3D structure of a nanocrystal can be determined ab initio at a resolution of 1 Angstrom from 29 simulated noisy diffraction patterns. This new form of microscopy can be used to image the 3D structures of nanocrystals and noncrystalline samples, with resolution limited only by the quality of sample diffraction

Experimental and theoretical study of rotationally inelastic diffraction of H2(D2) from methyl-terminated Si(111)

International Nuclear Information System (INIS)

Nihill, Kevin J.; Hund, Zachary M.; Sibener, S. J.; Muzas, Alberto; Cueto, Marcos del; Díaz, Cristina; Frankcombe, Terry; Plymale, Noah T.; Lewis, Nathan S.; Martín, Fernando

2016-01-01

Fundamental details concerning the interaction between H 2 and CH 3 –Si(111) have been elucidated by the combination of diffractive scattering experiments and electronic structure and scattering calculations. Rotationally inelastic diffraction (RID) of H 2 and D 2 from this model hydrocarbon-decorated semiconductor interface has been confirmed for the first time via both time-of-flight and diffraction measurements, with modest j = 0 → 2 RID intensities for H 2 compared to the strong RID features observed for D 2 over a large range of kinematic scattering conditions along two high-symmetry azimuthal directions. The Debye-Waller model was applied to the thermal attenuation of diffraction peaks, allowing for precise determination of the RID probabilities by accounting for incoherent motion of the CH 3 –Si(111) surface atoms. The probabilities of rotationally inelastic diffraction of H 2 and D 2 have been quantitatively evaluated as a function of beam energy and scattering angle, and have been compared with complementary electronic structure and scattering calculations to provide insight into the interaction potential between H 2 (D 2 ) and hence the surface charge density distribution. Specifically, a six-dimensional potential energy surface (PES), describing the electronic structure of the H 2 (D 2 )/CH 3 −Si(111) system, has been computed based on interpolation of density functional theory energies. Quantum and classical dynamics simulations have allowed for an assessment of the accuracy of the PES, and subsequently for identification of the features of the PES that serve as classical turning points. A close scrutiny of the PES reveals the highly anisotropic character of the interaction potential at these turning points. This combination of experiment and theory provides new and important details about the interaction of H 2 with a hybrid organic-semiconductor interface, which can be used to further investigate energy flow in technologically relevant systems.

New opportunities for 3D materials science of polycrystalline materials at the micrometre lengthscale by combined use of X-ray diffraction and X-ray imaging

Energy Technology Data Exchange (ETDEWEB)

Ludwig, W., E-mail: ludwig@esrf.fr [Universite de Lyon, INSA-Lyon, MATEIS CNRS UMR 5510, 69621Villeurbanne (France); European Synchrotron Radiation Facility, BP220, 38043 Grenoble (France); King, A. [European Synchrotron Radiation Facility, BP220, 38043 Grenoble (France); School of Materials, University of Manchester, Manchester, M13 9PL (United Kingdom); Reischig, P. [European Synchrotron Radiation Facility, BP220, 38043 Grenoble (France); Herbig, M. [Universite de Lyon, INSA-Lyon, MATEIS CNRS UMR 5510, 69621Villeurbanne (France); Lauridsen, E.M.; Schmidt, S. [Riso National Laboratory for Sustainable Energy, Technical University of Denmark, P.O. Box 49, DK-4000 Roskilde (Denmark); Proudhon, H.; Forest, S. [MINES ParisTech, Centre des materiaux, CNRS UMR 7633, BP 87, 91003 Evry Cedex (France); Cloetens, P.; Roscoat, S. Rolland du [European Synchrotron Radiation Facility, BP220, 38043 Grenoble (France); Buffiere, J.Y. [Universite de Lyon, INSA-Lyon, MATEIS CNRS UMR 5510, 69621Villeurbanne (France); Marrow, T.J. [School of Materials, University of Manchester, Manchester, M13 9PL (United Kingdom); Poulsen, H.F. [Riso National Laboratory for Sustainable Energy, Technical University of Denmark, P.O. Box 49, DK-4000 Roskilde (Denmark)

2009-10-25

Non-destructive, three-dimensional (3D) characterization of the grain structure in mono-phase polycrystalline materials is an open challenge in material science. Recent advances in synchrotron based X-ray imaging and diffraction techniques offer interesting possibilities for mapping 3D grain shapes and crystallographic orientations for certain categories of polycrystalline materials. Direct visualisation of the three-dimensional grain boundary network or of two-phase (duplex) grain structures by means of absorption and/or phase contrast techniques may be possible, but is restricted to specific material systems. A recent extension of this methodology, termed X-ray diffraction contrast tomography (DCT), combines the principles of X-ray diffraction imaging, three-dimensional X-ray diffraction microscopy (3DXRD) and image reconstruction from projections. DCT provides simultaneous access to 3D grain shape, crystallographic orientation and local attenuation coefficient distribution. The technique applies to the larger range of plastically undeformed, polycrystalline mono-phase materials, provided some conditions on grain size and texture are fulfilled. The straightforward combination with high-resolution microtomography opens interesting new possibilities for the observation of microstructure related damage and deformation mechanisms in these materials.

New opportunities for 3D materials science of polycrystalline materials at the micrometre lengthscale by combined use of X-ray diffraction and X-ray imaging

International Nuclear Information System (INIS)

Ludwig, W.; King, A.; Reischig, P.; Herbig, M.; Lauridsen, E.M.; Schmidt, S.; Proudhon, H.; Forest, S.; Cloetens, P.; Roscoat, S. Rolland du; Buffiere, J.Y.; Marrow, T.J.; Poulsen, H.F.

2009-01-01

Non-destructive, three-dimensional (3D) characterization of the grain structure in mono-phase polycrystalline materials is an open challenge in material science. Recent advances in synchrotron based X-ray imaging and diffraction techniques offer interesting possibilities for mapping 3D grain shapes and crystallographic orientations for certain categories of polycrystalline materials. Direct visualisation of the three-dimensional grain boundary network or of two-phase (duplex) grain structures by means of absorption and/or phase contrast techniques may be possible, but is restricted to specific material systems. A recent extension of this methodology, termed X-ray diffraction contrast tomography (DCT), combines the principles of X-ray diffraction imaging, three-dimensional X-ray diffraction microscopy (3DXRD) and image reconstruction from projections. DCT provides simultaneous access to 3D grain shape, crystallographic orientation and local attenuation coefficient distribution. The technique applies to the larger range of plastically undeformed, polycrystalline mono-phase materials, provided some conditions on grain size and texture are fulfilled. The straightforward combination with high-resolution microtomography opens interesting new possibilities for the observation of microstructure related damage and deformation mechanisms in these materials.

Mineralogical applications of electron diffraction. 1. Theory and techniques

Science.gov (United States)

Ross, Malcolm; Christ, C.L.

1958-01-01

The small wavelengths used in electron-diffraction experiments and the thinness of the crystals necessary for the transmission of the electron beam combine to require a somewhat different diffraction geometry for the interpretation of electron-diffraction patterns than is used in the interpretation of X-ray diffraction patterns. This geometry, based on the reciprocal lattice concept and geometrical construction of Ewald, needed for the interpretation.

3-D growth of a short fatigue crack within a polycrystalline microstructure studied using combined diffraction and phase-contrast X-ray tomography

DEFF Research Database (Denmark)

Herbig, M.; King, Andrew; Reischig, Peter

2011-01-01

X-ray diffraction contrast tomography is a recently developed, non-destructive synchrotron imaging technique which characterizes microstructure and grain orientation in polycrystalline materials in three dimensions. By combining it with propagation-based phase-contrast tomography it is possible t...

Hard diffraction and rapidity gaps

International Nuclear Information System (INIS)

Brandt, A.

1995-09-01

The field of hard diffraction, which studies events with a rapidity gap and a hard scattering, has expanded dramatically recently. A review of new results from CDF, D OE, H1 and ZEUS will be given. These results include diffractive jet production, deep-inelastic scattering in large rapidity gap events, rapidity gaps between high transverse energy jets, and a search for diffractive W-boson production. The combination of these results gives new insight into the exchanged object, believed to be the pomeron. The results axe consistent with factorization and with a hard pomeron that contains both quarks and gluons. There is also evidence for the exchange of a strongly interacting color singlet in high momentum transfer (36 2 ) events

Neutron diffraction and lattice defects

International Nuclear Information System (INIS)

Hamaguchi, Yoshikazu

1974-01-01

Study on lattice defects by neutron diffraction technique is described. Wave length of neutron wave is longer than that of X-ray, and absorption cross-section is small. Number of defects observed by ESR is up to several defects, and the number studied with electron microscopes is more than 100. Information obtained by neutron diffraction concerns the number of defects between these two ranges. For practical analysis, several probable models are selected from the data of ESR or electron microscopes, and most probable one is determined by calculation. Then, defect concentration is obtained from scattering cross section. It is possible to measure elastic scattering exclusively by neutron diffraction. Minimum detectable concentration estimated is about 0.5% and 10 20 - 10 21 defects per unit volume. A chopper and a time of flight system are used as a measuring system. Cold neutrons are obtained from the neutron sources inserted into reactors. Examples of measurements by using similar equipments to PTNS-I system of Japan Atomic Energy Research Institute are presented. Interstitial concentration in the graphite irradiated by fast neutrons is shown. Defects in irradiated MgO were also investigated by measuring scattering cross section. Study of defects in Ge was made by measuring total cross section, and model analysis was performed in comparison with various models. (Kato, T.)

Flight Test of an Intelligent Flight-Control System

Science.gov (United States)

Davidson, Ron; Bosworth, John T.; Jacobson, Steven R.; Thomson, Michael Pl; Jorgensen, Charles C.

2003-01-01

inputs with the outputs provided to instrumentation only. The IFCS was not used to control the airplane. In another stage of the flight test, the Phase I pre-trained neural network was integrated into a Phase III version of the flight control system. The Phase I pretrained neural network provided realtime stability and control derivatives to a Phase III controller that was based on a stochastic optimal feedforward and feedback technique (SOFFT). This combined Phase I/III system was operated together with the research flight-control system (RFCS) of the F-15 ACTIVE during the flight test. The RFCS enables the pilot to switch quickly from the experimental- research flight mode back to the safe conventional mode. These initial IFCS ACP flight tests were completed in April 1999. The Phase I/III flight test milestone was to demonstrate, across a range of subsonic and supersonic flight conditions, that the pre-trained neural network could be used to supply real-time aerodynamic stability and control derivatives to the closed-loop optimal SOFFT flight controller. Additional objectives attained in the flight test included (1) flight qualification of a neural-network-based control system; (2) the use of a combined neural-network/closed-loop optimal flight-control system to obtain level-one handling qualities; and (3) demonstration, through variation of control gains, that different handling qualities can be achieved by setting new target parameters. In addition, data for the Phase-II (on-line-learning) neural network were collected, during the use of stacked-frequency- sweep excitation, for post-flight analysis. Initial analysis of these data showed the potential for future flight tests that will incorporate the real-time identification and on-line learning aspects of the IFCS.

Characterization of a polychromatic neutron beam diffracted by pyrolytic graphite crystals

CERN Document Server

Byun, S H; Choi, H D

2002-01-01

The beam spectrum for polychromatic neutrons diffracted by pyrolytic graphite crystals was characterized. The theoretical beam spectrum was obtained using the diffraction model for a mosaic crystal. The lattice vibration effects were included in the calculation using the reported vibration amplitude of the crystal and the measured time-of-flight spectra in the thermal region. The calculated beam spectrum was compared with the results obtained in the absence of thermal motion. The lattice vibration effects became more important for the higher diffraction orders and a large decrease in the neutron flux induced by the vibrations was identified in the epithermal region. The validity of the beam spectrum was estimated by comparing with the effective quantities determined from prompt gamma-ray measurements and Cd-ratios measured both for 1/nu and non-1/nu nuclides.

Broadband and High Sensitive Time-of-Flight Diffraction Ultrasonic Transducers Based on PMNT/Epoxy 1–3 Piezoelectric Composite

Directory of Open Access Journals (Sweden)

Dongxu Liu

2015-03-01

Full Text Available 5–6 MHz PMNT/epoxy 1–3 composites were prepared by a modified dice-and-fill method. They exhibit excellent properties for ultrasonic transducer applications, such as ultrahigh thickness electromechanical coupling coefficient kt (85.7%, large piezoelectric coefficient d33 (1209 pC/N, and relatively low acoustic impedance Z (1.82 × 107 kg/(m2·s. Besides, two types of Time-of-Flight Diffraction (TOFD ultrasonic transducers have been designed, fabricated, and characterized, which have different matching layer schemes with the acoustic impedance of 4.8 and 5.7 × 106 kg/(m2·s, respectively. In the detection on a backwall of 12.7 mm polystyrene, the former exhibits higher detectivity, the relative pulse-echo sensitivity and −6 dB relative bandwidth are −21.93 dB and 102.7%, respectively, while the later exhibits broader bandwidth, the relative pulse-echo sensitivity and −6 dB relative bandwidth are −24.08 dB and 117.3%, respectively. These TOFD ultrasonic transducers based on PMNT/epoxy 1–3 composite exhibit considerably improved performance over the commercial PZT/epoxy 1–3 composite TOFD ultrasonic transducer.

Structure of 3 at.% and 9 at.% Si-doped HfO{sub 2} from combined refinement of X-ray and neutron diffraction patterns

Energy Technology Data Exchange (ETDEWEB)

Zhao, Lili [Department of Materials Science and Engineering, North Carolina State University, NC 27695 (United States); School of Information Science and Technology, Northwest University, Xi' an 710127 (China); Hou, Dong; Usher, Tedi-Marie; Iamsasri, Thanakorn; Fancher, Chris M.; Forrester, Jennifer S. [Department of Materials Science and Engineering, North Carolina State University, NC 27695 (United States); Nishida, Toshikazu [Department of Electrical and Computer Engineering, University of Florida, FL 32611 (United States); Moghaddam, Saeed [Department of Mechanical and Aerospace Engineering, University of Florida, FL 32611 (United States); Jones, Jacob L., E-mail: jacobjones@ncsu.edu [Department of Materials Science and Engineering, North Carolina State University, NC 27695 (United States)

2015-10-15

The crystal structure of 3 at.% and 9 at.% Si-doped HfO{sub 2} powder was determined through refinements using X-ray and neutron diffraction patterns. The lattice parameters, atomic positions, dopant occupancy, and the second phase fraction were determined with high precision using a combined full pattern fitting via the Rietveld method. The results show that both 3 at.% and 9 at.% Si-doped HfO{sub 2} powder exhibit the monoclinic crystal structure with P 1 2{sub 1}/c 1 space group. Through the combined refinement, the crystal structure parameters, especially for the positions and occupancies of the lighter atoms, were more precisely determined compared to independent X-ray diffraction refinement. Although the ionic radius of Si{sup 4+} is smaller than Hf{sup 4+}, with increasing Si occupancy, the unit cell volume slightly increases; possible mechanisms for this effect are discussed. Moreover, the refined results provide evidence of the existence of a non-equilibrium phase of Hf{sub x}Si{sub 1−x}O{sub 2}. The second phase (SiO{sub 2}) fraction is determined as 0.17 at.% for 3 at.% Si-doped HfO{sub 2} powders and 1.7 at.% for 9 at.% Si-doped HfO{sub 2} powders. - Highlights: • X-ray and neutron diffraction patterns were used to determine crystal structure. • Results from independent refinements and a combined refinement were compared. • Highly precise structural parameters were obtained by the combined refinement. • Structural data of 3 at.% and 9 at.% Si-doped HfO{sub 2} are provided. • The unit cell volume slightly increases with Si concentration from 3 to 9 at.%.

Developments in diffraction databases

International Nuclear Information System (INIS)

Jenkins, R.

1999-01-01

Full text: There are a number of databases available to the diffraction community. Two of the more important of these are the Powder Diffraction File (PDF) maintained by the International Centre for Diffraction Data (ICDD), and the Inorganic Crystal Structure Database (ICSD) maintained by Fachsinformationzentrum (FIZ, Karlsruhe). In application, the PDF has been used as an indispensable tool in phase identification and identification of unknowns. The ICSD database has extensive and explicit reference to the structures of compounds: atomic coordinates, space group and even thermal vibration parameters. A similar database, but for organic compounds, is maintained by the Cambridge Crystallographic Data Centre. These databases are often used as independent sources of information. However, little thought has been given on how to exploit the combined properties of structural database tools. A recently completed agreement between ICDD and FIZ, plus ICDD and Cambridge, provides a first step in complementary use of the PDF and the ICSD databases. The focus of this paper (as indicated below) is to examine ways of exploiting the combined properties of both databases. In 1996, there were approximately 76,000 entries in the PDF and approximately 43,000 entries in the ICSD database. The ICSD database has now been used to calculate entries in the PDF. Thus, to derive d-spacing and peak intensity data requires the synthesis of full diffraction patterns, i.e., we use the structural data in the ICSD database and then add instrumental resolution information. The combined data from PDF and ICSD can be effectively used in many ways. For example, we can calculate PDF data for an ideally random crystal distribution and also in the absence of preferred orientation. Again, we can use systematic studies of intermediate members in solid solutions series to help produce reliable quantitative phase analyses. In some cases, we can study how solid solution properties vary with composition and

In-flight Assessment of Lower Body Negative Pressure as a Countermeasure for Post-flight Orthostatic Intolerance

Science.gov (United States)

Charles, J. B.; Stenger, M. B.; Phillips, T. R.; Arzeno, N. M.; Lee, S. M. C.

2009-01-01

Introduction. We investigated the efficacy of combining fluid loading with sustained lower body negative pressure (LBNP) to reverse orthostatic intolerance associated with weightlessness during and immediately after Space Shuttle missions. Methods. Shuttle astronauts (n=13) underwent 4 hours of LBNP at -30 mm(Hg) and ingested water and salt ( soak treatment) during flight in two complementary studies. In the first study (n=8), pre-flight heart rate (HR) and blood pressure (BP) responses to an LBNP ramp (5-min stages of -10 mm(Hg) steps to -50 mm(Hg) were compared to responses in-flight one and two days after LBNP soak treatment. In the second study (n=5), the soak was performed 24 hr before landing, and post-flight stand test results of soak subjects were compared with those of an untreated cohort (n=7). In both studies, the soak was scheduled late in the mission and was preceded by LBNP ramp tests at approximately 3-day intervals to document the in-flight loss of orthostatic tolerance. Results. Increased HR and decreased BP responses to LBNP were evident early in-flight. In-flight, one day after LBNP soak, HR and BP responses to LBNP were not different from pre-flight, but the effect was absent the second day after treatment. Post-flight there were no between-group differences in HR and BP responses to standing, but all 5 treatment subjects completed the 5-minute stand test whereas 2 of 7 untreated cohort subjects did not. Discussion. Exaggerated HR and BP responses to LBNP were evident within the first few days of space flight, extending results from Skylab. The combined LBNP and fluid ingestion countermeasure restored in-flight LBNP HR and BP responses to pre-flight levels and provided protection of post-landing orthostatic function. Unfortunately, any benefits of the combined countermeasure were offset by the complexity of its implementation, making it inappropriate for routine application during Shuttle flights.

TOF neutron diffraction study of archaeological ceramics

International Nuclear Information System (INIS)

Kockelmann, W.; Kirfel, A.

1999-01-01

Complete text of publication follows. The time-of flight (TOF) neutron diffractometer ROTAX [1] at ISIS has been used for identification and quantitative phase analysis of archaeological pottery. Neutron diffraction yields mineral phase fractions which, in parallel with information obtained from other archaeometric examination techniques, can provide a fingerprint that can be used to identify provenance and reconstruct methods of manufacturing of an archaeological ceramic product. Phase fractions obtained from a 13th century Rhenish stoneware jar compare well with those obtained from a powder sample prepared from the same fragment. This indicates that reliable results can be obtained by illuminating a large piece or even an intact ceramic object making TOF neutron diffraction a truly non-destructive examination technique. In comparison to X-ray diffraction, information from the bulk sample rather than from surface regions is obtained. ROTAX allows for a simple experimental set-up, free of sample movements. Programmes of archaeological study on ROTAX involve Russian samples (Upper-Volga culture, 5000-2000 BC), Greek pottery, (Agora/Athens, 500-300 BC), and medieval German earthenware and stoneware ceramics (Siegburg waster heap, 13-15th century). (author)

Visualization of time-of-flight neutron diffraction data

International Nuclear Information System (INIS)

Mikkelson, D.J.; Price, D.L.; Worlton, T.G.

1995-01-01

The glass, liquids and amorphous materials diffractometer (GLAD) is a new instrument at the intense pulsed neutron source (IPNS) at Argonne National Laboratory. The GLAD currently has 218 linear position sensitive detectors arranged in five banks. Raw data collected from the instrument are typically split into 1000-1500 angular groups each of which contains approximately 2000 time channels. In order to obtain a meaningful overview of such a large amount of data, an interactive system to view the data has been designed. The system was implemented in C using the graphical kernel system (GKS) for portability.The system treats data from each bank of detectors as a three-dimensional data set with detector number, position along detector and time of flight as the three coordinate axes. The software then slices the data parallel to any of the coordinate planes and displays the slices as images. This approach has helped with the detailed analysis of detector electronics, verification of instrument calibration and resolution determination. In addition, it has helped to identify low-level background signals and provided insight into the overall operation of the instrument. ((orig.))

Inclusive measurements on diffractive processes in ep collisions

International Nuclear Information System (INIS)

Janssen, Xavier

2007-01-01

Measurements from the H1 and ZEUS collaborations of the diffractive deep-inelastic scattering process, ep → eXY, where Y is a proton or a low mass proton excitation, are presented for photon virtualities in the range 2.2 2 2 and squared four-momentum transfer at the proton vertex satisfying | t | 2 . Diffractive parton distribution functions and their uncertainties are determined from a next-to-leading order DGLAP QCD analysis. Combining measurements of the inclusive diffractive deep-inelastic scattering process with an analysis of diffractive di jet production allows a very sensitive determination of both quark and gluon distributions. (author)

Combining the multilevel fast multipole method with the uniform geometrical theory of diffraction

Directory of Open Access Journals (Sweden)

A. Tzoulis

2005-01-01

Full Text Available The presence of arbitrarily shaped and electrically large objects in the same environment leads to hybridization of the Method of Moments (MoM with the Uniform Geometrical Theory of Diffraction (UTD. The computation and memory complexity of the MoM solution is improved with the Multilevel Fast Multipole Method (MLFMM. By expanding the k-space integrals in spherical harmonics, further considerable amount of memory can be saved without compromising accuracy and numerical speed. However, until now MoM-UTD hybrid methods are restricted to conventional MoM formulations only with Electric Field Integral Equation (EFIE. In this contribution, a MLFMM-UTD hybridization for Combined Field Integral Equation (CFIE is proposed and applied within a hybrid Finite Element - Boundary Integral (FEBI technique. The MLFMM-UTD hybridization is performed at the translation procedure on the various levels of the MLFMM, using a far-field approximation of the corresponding translation operator. The formulation of this new hybrid technique is presented, as well as numerical results.

Applications of TOF neutron diffraction in archaeometry

Energy Technology Data Exchange (ETDEWEB)

Kockelmann, W. [Rutherford Appleton Laboratory, ISIS Facility, Chilton (United Kingdom); Siano, S.; Bartoli, L. [Istituto di Fisica Applicata - CNR, Sesto Fiorentino (Italy); Visser, D. [Rutherford Appleton Laboratory, ISIS Facility, Chilton (United Kingdom); Netherlands Organisation for Scientific Research (NWO), Den Haag (Netherlands); Hallebeek, P. [Netherlands Institute for Cultural Heritage (ICN), Amsterdam (Netherlands); Traum, R. [Kunsthistorisches Museum Wien, Muenzkabinett, Vienna (Austria); Linke, R.; Schreiner, M. [Akademie der Bildenden Kuenste, Institut fuer Wissenschaften und Technologien in der Kunst, Vienna (Austria); Kirfel, A. [Universitaet Bonn, Mineralogisch-Petrologisches Institut, Bonn (Germany)

2006-05-15

Neutron radiation meets the demand for a versatile diagnostic probe for collecting information from the interior of large, undisturbed museum objects or archaeological findings. Neutrons penetrate through coatings and corrosion layers deep into centimetre-thick materials, a property that makes them ideal for non-destructive examination of objects for which sampling is impractical or unacceptable. A particular attraction of neutron techniques for archaeologists and conservation scientists is the prospect of locating hidden materials and structures inside objects. Time-of-flight (TOF) neutron diffraction allows for the examination of mineral and metal phase contents, crystal structures, grain orientations, and microstructures as well as micro- and macro strains. A promising application is texture analysis which may provide clues to the deformation history of the material, and hence to specific working processes. Here we report on instructive examples of TOF neutron diffraction, including phase analyses of medieval Dutch tin-lead spoons, texture analyses of bronze specimens as well as of 16th-century silver coins. (orig.)

Advanced x-ray stress analysis method for a single crystal using different diffraction plane families

International Nuclear Information System (INIS)

Imafuku, Muneyuki; Suzuki, Hiroshi; Sueyoshi, Kazuyuki; Akita, Koichi; Ohya, Shin-ichi

2008-01-01

Generalized formula of the x-ray stress analysis for a single crystal with unknown stress-free lattice parameter was proposed. This method enables us to evaluate the plane stress states with any combination of diffraction planes. We can choose and combine the appropriate x-ray sources and diffraction plane families, depending on the sample orientation and the apparatus, whenever diffraction condition is satisfied. The analysis of plane stress distributions in an iron single crystal was demonstrated combining with the diffraction data for Fe{211} and Fe{310} plane families

Jets and diffraction results from HERA

International Nuclear Information System (INIS)

Buniatyan, A.

2014-01-01

The latest results on precision measurements of jet and diffractive cross sections obtained by the H1 and ZEUS experiments at HERA are reported. The inclusive jet and multi-jet cross-sections are used in QCD calculations at next-to-leading order (NLO) to determine the strong coupling α s . The cross-section measurements for diffractive inclusive DIS processes with a leading proton in the final state are combined for the H1 and ZEUS experiments in order to improve the precision and extend the kinematic range. The di-jet cross sections are measured in diffractive DIS with a leading proton and compared with QCD predictions based on diffractive parton densities in the proton. The cross sections for exclusive heavy vector meson photoproduction are studied in terms of the momentum transfer at the proton vertex and of the photon-proton centre-of-mass energy. (author)

Encoded diffractive optics for full-spectrum computational imaging

KAUST Repository

Heide, Felix; Fu, Qiang; Peng, Yifan; Heidrich, Wolfgang

2016-01-01

Diffractive optical elements can be realized as ultra-thin plates that offer significantly reduced footprint and weight compared to refractive elements. However, such elements introduce severe chromatic aberrations and are not variable, unless used in combination with other elements in a larger, reconfigurable optical system. We introduce numerically optimized encoded phase masks in which different optical parameters such as focus or zoom can be accessed through changes in the mechanical alignment of a ultra-thin stack of two or more masks. Our encoded diffractive designs are combined with a new computational approach for self-calibrating imaging (blind deconvolution) that can restore high-quality images several orders of magnitude faster than the state of the art without pre-calibration of the optical system. This co-design of optics and computation enables tunable, full-spectrum imaging using thin diffractive optics.

Encoded diffractive optics for full-spectrum computational imaging

KAUST Repository

Heide, Felix

2016-09-16

Diffractive optical elements can be realized as ultra-thin plates that offer significantly reduced footprint and weight compared to refractive elements. However, such elements introduce severe chromatic aberrations and are not variable, unless used in combination with other elements in a larger, reconfigurable optical system. We introduce numerically optimized encoded phase masks in which different optical parameters such as focus or zoom can be accessed through changes in the mechanical alignment of a ultra-thin stack of two or more masks. Our encoded diffractive designs are combined with a new computational approach for self-calibrating imaging (blind deconvolution) that can restore high-quality images several orders of magnitude faster than the state of the art without pre-calibration of the optical system. This co-design of optics and computation enables tunable, full-spectrum imaging using thin diffractive optics.

Spatial Power Combining Amplifier for Ground and Flight Applications

Science.gov (United States)

Velazco, J. E.; Taylor, M.

2016-11-01

Vacuum-tube amplifiers such as klystrons and traveling-wave tubes are the workhorses of high-power microwave radiation generation. At JPL, vacuum tubes are extensively used in ground and flight missions for radar and communications. Vacuum tubes use electron beams as the source of energy to achieve microwave power amplification. Such electron beams operate at high kinetic energies and thus require high voltages to function. In addition, vacuum tubes use compact cavity and waveguide structures that hold very intense radio frequency (RF) fields inside. As the operational frequency is increased, the dimensions of these RF structures become increasingly smaller. As power levels and operational frequencies are increased, the highly intense RF fields inside of the tubes' structures tend to arc and create RF breakdown. In the case of very high-power klystrons, electron interception - also known as body current - can produce thermal runaway of the cavities that could lead to the destruction of the tube. The high voltages needed to power vacuum tubes tend to require complicated and cumbersome power supplies. Consequently, although vacuum tubes provide unmatched high-power microwaves, they tend to arc, suffer from thermal issues, and require failure-prone high-voltage power supplies. In this article, we present a new concept for generating high-power microwaves that we refer to as the Spatial Power Combining Amplifier (SPCA). The SPCA is very compact, requires simpler, lower-voltage power supplies, and uses a unique power-combining scheme wherein power from solid-state amplifiers is coherently combined. It is a two-port amplifier and can be used inline as any conventional two-port amplifier. It can deliver its output power to a coaxial line, a waveguide, a feed, or to any microwave load. A key feature of this new scheme is the use of higher-order-mode microwave structures to spatially divide and combine power. Such higher-order-mode structures have considerably larger cross

High resolution X-ray diffraction studies on unirradiated

Indian Academy of Sciences (India)

High-resolution X-ray diffraction technique, employing a three-crystal monochromator–collimator combination is used to study the irradiation induced defects in flux grown Sr-hexaferrite crystals irradiated with 50 MeV Li3+ ion beams at room temperature with a fluence value of 1 × 1014 ions/cm2. The diffraction curves of the ...

Diffractive flat panel solar concentrators of a novel design

NARCIS (Netherlands)

De Jong, T.M.; de Boer, D.K.G.; Bastiaansen, C.W.M.

2016-01-01

A novel design for a flat panel solar concentrator is presented which is based on a light guide with a grating applied on top that diffracts light into total internal reflection. By combining geometrical and diffractive optics the geometrical concentration ratio is optimized according to the

Combining control input with flight path data to evaluate pilot performance in transport aircraft.

Science.gov (United States)

Ebbatson, Matt; Harris, Don; Huddlestone, John; Sears, Rodney

2008-11-01

When deriving an objective assessment of piloting performance from flight data records, it is common to employ metrics which purely evaluate errors in flight path parameters. The adequacy of pilot performance is evaluated from the flight path of the aircraft. However, in large jet transport aircraft these measures may be insensitive and require supplementing with frequency-based measures of control input parameters. Flight path and control input data were collected from pilots undertaking a jet transport aircraft conversion course during a series of symmetric and asymmetric approaches in a flight simulator. The flight path data were analyzed for deviations around the optimum flight path while flying an instrument landing approach. Manipulation of the flight controls was subject to analysis using a series of power spectral density measures. The flight path metrics showed no significant differences in performance between the symmetric and asymmetric approaches. However, control input frequency domain measures revealed that the pilots employed highly different control strategies in the pitch and yaw axes. The results demonstrate that to evaluate pilot performance fully in large aircraft, it is necessary to employ performance metrics targeted at both the outer control loop (flight path) and the inner control loop (flight control) parameters in parallel, evaluating both the product and process of a pilot's performance.

Development and applications of the reverse neutron time-of-flight method with Fourier-type beam chopper

International Nuclear Information System (INIS)

Antson, O.

1991-09-01

The neutron powder diffraction method has been applied to the crystal structure analysis of high-temperature superconductors such as La 0 .8Sr 0 .2CuO 4 - y , YBa 2 Cu 3 O 7 - y and Bi 2 Sr 2 CaCu 2 O 8 + y optically active yttriumformate Y(HCOO) 3 , and β phase of deuterated acetonitrile, CD 3 CN. The structural information, containing symmetry, positional and thermal parameters, occupation factors and the order parameter, was obtained by measuring the coherent elastic scattering cross-section. The Rietveld profile refinement method was used for the extraction of structural parameters from experimental data. The diffraction spectra were obtained by measuring the time-of-flight distribution of neutrons with a Fourier-type beam chopper. The neutron diffraction spectrum is created by the on-line synthesis of the cross-correlation function between the beam modulation function and the detector intensity. Such an operational mode, called the reverse time-of-flight method, has many unique properties. The possibility of filtering out a low-frequency part of a diffraction spectrum, eg. incoherent background, by a properly selected band-pass filter has been studied. One of the practical applications of the reverse time-of-flight method, the Mini-Sfinks facility, is described with technical details, and its operational characteristics are compared with other high-resolution instruments

Quasi-Bragg diffraction of atoms

NARCIS (Netherlands)

Domen, K.F.E.M.; Jansen, M.A.H.M.; Leeuwen, van K.A.H.

2006-01-01

We report on a novel atomic beamsplitter. It combines the advantages of Bragg scattering (transfer possible into a single, very high diffraction order due to adiabatic conservation of ‘transverse kinetic energy’) with the convenience of tuning the splitting angle simply by adjusting a magnetic

Computational imaging using lightweight diffractive-refractive optics

KAUST Repository

Peng, Yifan

2015-11-23

Diffractive optical elements (DOE) show great promise for imaging optics that are thinner and more lightweight than conventional refractive lenses while preserving their light efficiency. Unfortunately, severe spectral dispersion currently limits the use of DOEs in consumer-level lens design. In this article, we jointly design lightweight diffractive-refractive optics and post-processing algorithms to enable imaging under white light illumination. Using the Fresnel lens as a general platform, we show three phase-plate designs, including a super-thin stacked plate design, a diffractive-refractive-hybrid lens, and a phase coded-aperture lens. Combined with cross-channel deconvolution algorithm, both spherical and chromatic aberrations are corrected. Experimental results indicate that using our computational imaging approach, diffractive-refractive optics is an alternative candidate to build light efficient and thin optics for white light imaging.

Computational imaging using lightweight diffractive-refractive optics

KAUST Repository

Peng, Yifan; Fu, Qiang; Amata, Hadi; Su, Shuochen; Heide, Felix; Heidrich, Wolfgang

2015-01-01

Diffractive optical elements (DOE) show great promise for imaging optics that are thinner and more lightweight than conventional refractive lenses while preserving their light efficiency. Unfortunately, severe spectral dispersion currently limits the use of DOEs in consumer-level lens design. In this article, we jointly design lightweight diffractive-refractive optics and post-processing algorithms to enable imaging under white light illumination. Using the Fresnel lens as a general platform, we show three phase-plate designs, including a super-thin stacked plate design, a diffractive-refractive-hybrid lens, and a phase coded-aperture lens. Combined with cross-channel deconvolution algorithm, both spherical and chromatic aberrations are corrected. Experimental results indicate that using our computational imaging approach, diffractive-refractive optics is an alternative candidate to build light efficient and thin optics for white light imaging.

Gaussian beam diffraction in weakly anisotropic inhomogeneous media

Energy Technology Data Exchange (ETDEWEB)

Kravtsov, Yu.A., E-mail: kravtsov@am.szczecin.p [Institute of Physics, Maritime University of Szczecin, Szczecin 70-500 (Poland); Space Research Institute, Russian Academy of Science, Moscow 117 997 (Russian Federation); Berczynski, P., E-mail: pawel.berczynski@ps.p [Institute of Physics, West Pomeranian University of Technology, Szczecin 70-310 (Poland); Bieg, B., E-mail: b.bieg@am.szczecin.p [Institute of Physics, Maritime University of Szczecin, Szczecin 70-500 (Poland)

2009-08-10

Combination of quasi-isotropic approximation (QIA) of geometric optics with paraxial complex geometric optics (PCGO) is suggested, which allows describing both diffraction and polarization evolution of Gaussian electromagnetic beams in weakly anisotropic inhomogeneous media. Combination QIA/PCGO reduces Maxwell equations to the system of the ordinary differential equations of the first order and radically simplifies solution of various problems, related to microwave plasma diagnostics, including plasma polarimetry, interferometry and refractometry in thermonuclear reactors. Efficiency of the method is demonstrated by the example of electromagnetic beam diffraction in a linear layer of magnetized plasma with parameters, modeling tokamak plasma in the project ITER.

Gaussian beam diffraction in weakly anisotropic inhomogeneous media

International Nuclear Information System (INIS)

Kravtsov, Yu.A.; Berczynski, P.; Bieg, B.

2009-01-01

Combination of quasi-isotropic approximation (QIA) of geometric optics with paraxial complex geometric optics (PCGO) is suggested, which allows describing both diffraction and polarization evolution of Gaussian electromagnetic beams in weakly anisotropic inhomogeneous media. Combination QIA/PCGO reduces Maxwell equations to the system of the ordinary differential equations of the first order and radically simplifies solution of various problems, related to microwave plasma diagnostics, including plasma polarimetry, interferometry and refractometry in thermonuclear reactors. Efficiency of the method is demonstrated by the example of electromagnetic beam diffraction in a linear layer of magnetized plasma with parameters, modeling tokamak plasma in the project ITER.

Efficient concept for generation of diffraction-limited green light by sum-frequency generation of spectrally combined tapered diode lasers

DEFF Research Database (Denmark)

Müller, André; Jensen, Ole Bjarlin; Hasler, Karl-Heinz

2012-01-01

In order to increase the power of visible diode laser systems in an efficient manner, we propose spectral beam combining with subsequent sum-frequency generation. We show that this approach, in comparison with second harmonic generation of single emitters, can enhance the available power signific......In order to increase the power of visible diode laser systems in an efficient manner, we propose spectral beam combining with subsequent sum-frequency generation. We show that this approach, in comparison with second harmonic generation of single emitters, can enhance the available power...... significantly. By combining two distributed Bragg reflector tapered diode lasers we achieve a 2.5–3.2 fold increase in power and a maximum of 3.9 W of diffraction-limited green light. At this power level, green diode laser systems have a high application potential, e.g., within the biomedical field. Our concept...

Order-disorder-reorder process in thermally treated dolomite samples: a combined powder and single-crystal X-ray diffraction study

Science.gov (United States)

Zucchini, A.; Comodi, P.; Katerinopoulou, A.; Balic-Zunic, T.; McCammon, C.; Frondini, F.

2012-04-01

A combined powder and single-crystal X-ray diffraction analysis of dolomite [CaMg(CO3)2] heated to 1,200°C at 3 GPa was made to study the order-disorder-reorder process. The order/disorder transition is inferred to start below 1,100°C, and complete disorder is attained at approximately 1,200°C. Twinned crystals characterized by high internal order were found in samples annealed over 1,100°C, and their fraction was found to increase with temperature. Evidences of twinning domains combined with probable remaining disordered portions of the structure imply that reordering processes occur during the quench. Twin domains are hereby proposed as a witness to thermally induced intra-layer-type cation disordering.

In situ analysis of elemental depth distributions in thin films by combined evaluation of synchrotron x-ray fluorescence and diffraction

International Nuclear Information System (INIS)

Mainz, R.; Klenk, R.

2011-01-01

In this work we present a method for the in situ analysis of elemental depth distributions in thin films using a combined evaluation of synchrotron x-ray fluorescence and energy-dispersive x-ray diffraction signals. We recorded diffraction and fluorescence signals simultaneously during the reactive annealing of thin films. By means of the observed diffraction signals, the time evolution of phases in the thin films during the annealing processes can be determined. We utilized this phase information to parameterize the depth distributions of the elements in the films. The time-dependent fluorescence signals were then taken to determine the parameters representing the parameterized depth distributions. For this latter step, we numerically calculated the fluorescence intensities for a given set of depth distributions. These calculations handle polychromatic excitation and arbitrary functions of depth distributions and take into account primary and secondary fluorescence. Influences of lateral non-uniformities of the films, as well as the accuracy limits of the method, are investigated. We apply the introduced method to analyze the evolution of elemental depth distributions and to quantify the kinetic parameters during a synthesis process of CuInS 2 thin films via the reactive annealing of Cu-In precursors in a sulfur atmosphere.

First spin-resolved electron distributions in crystals from combined polarized neutron and X-ray diffraction experiments

Directory of Open Access Journals (Sweden)

Maxime Deutsch

2014-05-01

Full Text Available Since the 1980s it has been possible to probe crystallized matter, thanks to X-ray or neutron scattering techniques, to obtain an accurate charge density or spin distribution at the atomic scale. Despite the description of the same physical quantity (electron density and tremendous development of sources, detectors, data treatment software etc., these different techniques evolved separately with one model per experiment. However, a breakthrough was recently made by the development of a common model in order to combine information coming from all these different experiments. Here we report the first experimental determination of spin-resolved electron density obtained by a combined treatment of X-ray, neutron and polarized neutron diffraction data. These experimental spin up and spin down densities compare very well with density functional theory (DFT calculations and also confirm a theoretical prediction made in 1985 which claims that majority spin electrons should have a more contracted distribution around the nucleus than minority spin electrons. Topological analysis of the resulting experimental spin-resolved electron density is also briefly discussed.

First spin-resolved electron distributions in crystals from combined polarized neutron and X-ray diffraction experiments.

Science.gov (United States)

Deutsch, Maxime; Gillon, Béatrice; Claiser, Nicolas; Gillet, Jean-Michel; Lecomte, Claude; Souhassou, Mohamed

2014-05-01

Since the 1980s it has been possible to probe crystallized matter, thanks to X-ray or neutron scattering techniques, to obtain an accurate charge density or spin distribution at the atomic scale. Despite the description of the same physical quantity (electron density) and tremendous development of sources, detectors, data treatment software etc., these different techniques evolved separately with one model per experiment. However, a breakthrough was recently made by the development of a common model in order to combine information coming from all these different experiments. Here we report the first experimental determination of spin-resolved electron density obtained by a combined treatment of X-ray, neutron and polarized neutron diffraction data. These experimental spin up and spin down densities compare very well with density functional theory (DFT) calculations and also confirm a theoretical prediction made in 1985 which claims that majority spin electrons should have a more contracted distribution around the nucleus than minority spin electrons. Topological analysis of the resulting experimental spin-resolved electron density is also briefly discussed.

Submicron X-ray diffraction

International Nuclear Information System (INIS)

MacDowell, Alastair; Celestre, Richard; Tamura, Nobumichi; Spolenak, Ralph; Valek, Bryan; Brown, Walter; Bravman, John; Padmore, Howard; Batterman, Boris; Patel, Jamshed

2000-01-01

At the Advanced Light Source in Berkeley the authors have instrumented a beam line that is devoted exclusively to x-ray micro diffraction problems. By micro diffraction they mean those classes of problems in Physics and Materials Science that require x-ray beam sizes in the sub-micron range. The instrument is for instance, capable of probing a sub-micron size volume inside micron sized aluminum metal grains buried under a silicon dioxide insulating layer. The resulting Laue pattern is collected on a large area CCD detector and automatically indexed to yield the grain orientation and deviatoric (distortional) strain tensor of this sub-micron volume. A four-crystal monochromator is then inserted into the beam, which allows monochromatic light to illuminate the same part of the sample. Measurement of diffracted photon energy allows for the determination of d spacings. The combination of white and monochromatic beam measurements allow for the determination of the total strain/stress tensor (6 components) inside each sub-micron sized illuminated volume of the sample

Tolerance analysis on diffraction efficiency and polychromatic integral diffraction efficiency for harmonic diffractive optics

Science.gov (United States)

Shan, Mao

2016-10-01

In this dissertation, the mathematical model of effect of manufacturing errors including microstructure relative height error and relative width error on diffraction efficiency for the harmonic diffractive optical elements (HDEs) is set up. According to the expression of the phase delay and diffraction efficiency of the HDEs, the expression of diffraction efficiency of refraction and diffractive optical element with the microstructure height and periodic width errors in fabrication process is presented in this paper. Furthermore, the effect of manufacturing errors on diffraction efficiency for the harmonic diffractive optical elements is studied, and diffraction efficiency change is analyzed as the relative microstructure height-error in the same and in the opposite sign as well as relative width-error in the same and in the opposite sign. Example including infrared wavelength with materials GE has been discussed in this paper. Two kinds of manufacturing errors applied in 3.7 4.3um middle infrared and 8.7-11.5um far infrared optical system which results in diffraction efficiency and PIDE of HDEs are studied. The analysis results can be used for manufacturing error control in micro-structure height and periodic width. Results can be used for HDEs processing.

Experimental and theoretical study of rotationally inelastic diffraction of H{sub 2}(D{sub 2}) from methyl-terminated Si(111)

Energy Technology Data Exchange (ETDEWEB)

Nihill, Kevin J.; Hund, Zachary M.; Sibener, S. J., E-mail: s-sibener@uchicago.edu [The James Franck Institute and Department of Chemistry, The University of Chicago, 929 E. 57th Street, Chicago, Illinois 60637 (United States); Muzas, Alberto; Cueto, Marcos del [Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Díaz, Cristina [Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid (Spain); Frankcombe, Terry [School of Physical, Environmental and Mathematical Sciences, University of New South Wales, Canberra ACT 2610 (Australia); Plymale, Noah T.; Lewis, Nathan S. [Division of Chemistry and Chemical Engineering, Beckman Institute and Kavli Nanoscience Institute, California Institute of Technology, 210 Noyes Laboratory, 127-72, Pasadena, California 91125 (United States); Martín, Fernando [Departamento de Química, Módulo 13, Universidad Autónoma de Madrid, 28049 Madrid (Spain); Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, 28049 Madrid (Spain); Instituto Madrileño de Estudios Avanzados en Nanociencia (IMDEA-Nanociencia), Cantoblanco, 28049 Madrid (Spain)

2016-08-28

Fundamental details concerning the interaction between H{sub 2} and CH{sub 3}–Si(111) have been elucidated by the combination of diffractive scattering experiments and electronic structure and scattering calculations. Rotationally inelastic diffraction (RID) of H{sub 2} and D{sub 2} from this model hydrocarbon-decorated semiconductor interface has been confirmed for the first time via both time-of-flight and diffraction measurements, with modest j = 0 → 2 RID intensities for H{sub 2} compared to the strong RID features observed for D{sub 2} over a large range of kinematic scattering conditions along two high-symmetry azimuthal directions. The Debye-Waller model was applied to the thermal attenuation of diffraction peaks, allowing for precise determination of the RID probabilities by accounting for incoherent motion of the CH{sub 3}–Si(111) surface atoms. The probabilities of rotationally inelastic diffraction of H{sub 2} and D{sub 2} have been quantitatively evaluated as a function of beam energy and scattering angle, and have been compared with complementary electronic structure and scattering calculations to provide insight into the interaction potential between H{sub 2} (D{sub 2}) and hence the surface charge density distribution. Specifically, a six-dimensional potential energy surface (PES), describing the electronic structure of the H{sub 2}(D{sub 2})/CH{sub 3}−Si(111) system, has been computed based on interpolation of density functional theory energies. Quantum and classical dynamics simulations have allowed for an assessment of the accuracy of the PES, and subsequently for identification of the features of the PES that serve as classical turning points. A close scrutiny of the PES reveals the highly anisotropic character of the interaction potential at these turning points. This combination of experiment and theory provides new and important details about the interaction of H{sub 2} with a hybrid organic-semiconductor interface, which can be used

Profile analysis of neutron powder diffraction data at ISIS

International Nuclear Information System (INIS)

David, W.I.F.; Ibberson, R.M.; Matthewman, J.C.

1992-05-01

The aim of this manual is to document the current suite of time-of-flight neutron powder diffraction profile refinement programs available to ISIS users. Aspects of data collation and normalisation specific to the individual diffraction instruments are dealt with elsewhere. It will be assumed the user has produced a suitable data file (.DAT file) containing the profile data consisting of point by point values of the corrected diffraction profile across the pattern. The analysis of neutron powder diffraction data at ISIS by profile refinement utilises a suite of ''in-house'' written and supported programs based on the Cambridge Crystallography Subroutine Library (CCSL). A quick scan through the CCSL manual will give the user a general feel for the procedure to adopt in the use of the library and hence of the profile codes. The instructions documented in this handbook are complementary to those in the more specialist CCSL manual, and consequently go into no great detail regarding technical details of any of the CCSL routines. The programs may be run from each individual user account, for example [USER01], once the appropriate login procedure has been set-up by the instrument scientists. The programs are mostly activated by one line commands and only a basic knowledge of a VAX editor should be required; details can be found in the ''VAX primer'' available from Computer Support. (Author)

Time-of-flight neutron diffractometer for monocrystal study

International Nuclear Information System (INIS)

Anan'ev, B.N.; Balagurov, A.M.; Barabash, I.P.; Georgiu, Z.; Shibaev, V.D.

1979-01-01

The design of a neutron diffractometer is discussed. It is used for structural analysis of single crystals on the basis of time-of-flight measurements. The diffractometer is positioned along the axis of a beam of the IBR-30 pulse reactor, its average power is 29 kW. The mechanical part of the diffractometer consists of a massive foundation with a threeaxial goniometer, a rotatable platform with a collimator and a 3 He counter. The flowsheet of a control unit is given, which is used to position the rotatable platform of the diffractometer. The control unit includes a 14 digic binary counter for rotation angle recording, a parallel-to-series converter, a control signal shaper, two position shift registers, and a servo mechanism. The accuracy of diffraction maxima is evaluated. It is found that the ratio D(t)sup(1/2)/t (D(t) is a time dispersion of diffraction maxima, t is total time-of-flight time), which characterize the resolution of the diffractometer, is equal to 0.5% at the Bragg angle Q=45 deg and the neutron wavelength Λ=1 A

Combining X-ray Absorption and X-ray Diffraction Techniques for in Situ Studies of Chemical Transformations in Heterogeneous Catalysis: Advantages and Limitations

International Nuclear Information System (INIS)

Frenkel, A.I.; Hanson, J.; Wang, Q.; Marinkovic, N.; Chen, J.G.; Barrio, L.; Si, R.; Lopez Camara, A.; Estrella, A.M.; Rodriguez, J.A.

2011-01-01

Recent advances in catalysis instrumentations include synchrotron-based facilities where time-resolved X-ray scattering and absorption techniques are combined in the same in situ or operando experiment to study catalysts at work. To evaluate the advances and limitations of this method, we performed a series of experiments at the new XAFS/XRD instrument in the National Synchrotron Light Source. Nearly simultaneous X-ray diffraction (XRD) and X-ray absorption fine-structure (XAFS) measurements of structure and kinetics of several catalysts under reducing or oxidizing conditions have been performed and carefully analyzed. For CuFe 2 O 4 under reducing conditions, the combined use of the two techniques allowed us to obtain accurate data on kinetics of nucleation and growth of metallic Cu. For the inverse catalyst CuO/CeO 2 that underwent isothermal reduction (with CO) and oxidation (with O 2 ), the XAFS data measured in the same experiment with XRD revealed strongly disordered Cu species that went undetected by diffraction. These and other examples emphasize the unique sensitivity of these two complementary methods to follow catalytic processes in the broad ranges of length and time scales.

Combined operando X-ray diffraction-electrochemical impedance spectroscopy detecting solid solution reactions of LiFePO4 in batteries.

Science.gov (United States)

Hess, Michael; Sasaki, Tsuyoshi; Villevieille, Claire; Novák, Petr

2015-09-08

Lithium-ion batteries are widely used for portable applications today; however, often suffer from limited recharge rates. One reason for such limitation can be a reduced active surface area during phase separation. Here we report a technique combining high-resolution operando synchrotron X-ray diffraction coupled with electrochemical impedance spectroscopy to directly track non-equilibrium intermediate phases in lithium-ion battery materials. LiFePO4, for example, is known to undergo phase separation when cycled under low-current-density conditions. However, operando X-ray diffraction under ultra-high-rate alternating current and direct current excitation reveal a continuous but current-dependent, solid solution reaction between LiFePO4 and FePO4 which is consistent with previous experiments and calculations. In addition, the formation of a preferred phase with a composition similar to the eutectoid composition, Li0.625FePO4, is evident. Even at a low rate of 0.1C, ∼20% of the X-ray diffractogram can be attributed to non-equilibrium phases, which changes our understanding of the intercalation dynamics in LiFePO4.

Three-dimensional electron diffraction as a complementary technique to powder X-ray diffraction for phase identification and structure solution of powders

Directory of Open Access Journals (Sweden)

Yifeng Yun

2015-03-01

Full Text Available Phase identification and structure determination are important and widely used techniques in chemistry, physics and materials science. Recently, two methods for automated three-dimensional electron diffraction (ED data collection, namely automated diffraction tomography (ADT and rotation electron diffraction (RED, have been developed. Compared with X-ray diffraction (XRD and two-dimensional zonal ED, three-dimensional ED methods have many advantages in identifying phases and determining unknown structures. Almost complete three-dimensional ED data can be collected using the ADT and RED methods. Since each ED pattern is usually measured off the zone axes by three-dimensional ED methods, dynamic effects are much reduced compared with zonal ED patterns. Data collection is easy and fast, and can start at any arbitrary orientation of the crystal, which facilitates automation. Three-dimensional ED is a powerful technique for structure identification and structure solution from individual nano- or micron-sized particles, while powder X-ray diffraction (PXRD provides information from all phases present in a sample. ED suffers from dynamic scattering, while PXRD data are kinematic. Three-dimensional ED methods and PXRD are complementary and their combinations are promising for studying multiphase samples and complicated crystal structures. Here, two three-dimensional ED methods, ADT and RED, are described. Examples are given of combinations of three-dimensional ED methods and PXRD for phase identification and structure determination over a large number of different materials, from Ni–Se–O–Cl crystals, zeolites, germanates, metal–organic frameworks and organic compounds to intermetallics with modulated structures. It is shown that three-dimensional ED is now as feasible as X-ray diffraction for phase identification and structure solution, but still needs further development in order to be as accurate as X-ray diffraction. It is expected that three

Three-dimensional electron diffraction as a complementary technique to powder X-ray diffraction for phase identification and structure solution of powders.

Science.gov (United States)

Yun, Yifeng; Zou, Xiaodong; Hovmöller, Sven; Wan, Wei

2015-03-01

Phase identification and structure determination are important and widely used techniques in chemistry, physics and materials science. Recently, two methods for automated three-dimensional electron diffraction (ED) data collection, namely automated diffraction tomography (ADT) and rotation electron diffraction (RED), have been developed. Compared with X-ray diffraction (XRD) and two-dimensional zonal ED, three-dimensional ED methods have many advantages in identifying phases and determining unknown structures. Almost complete three-dimensional ED data can be collected using the ADT and RED methods. Since each ED pattern is usually measured off the zone axes by three-dimensional ED methods, dynamic effects are much reduced compared with zonal ED patterns. Data collection is easy and fast, and can start at any arbitrary orientation of the crystal, which facilitates automation. Three-dimensional ED is a powerful technique for structure identification and structure solution from individual nano- or micron-sized particles, while powder X-ray diffraction (PXRD) provides information from all phases present in a sample. ED suffers from dynamic scattering, while PXRD data are kinematic. Three-dimensional ED methods and PXRD are complementary and their combinations are promising for studying multiphase samples and complicated crystal structures. Here, two three-dimensional ED methods, ADT and RED, are described. Examples are given of combinations of three-dimensional ED methods and PXRD for phase identification and structure determination over a large number of different materials, from Ni-Se-O-Cl crystals, zeolites, germanates, metal-organic frameworks and organic compounds to intermetallics with modulated structures. It is shown that three-dimensional ED is now as feasible as X-ray diffraction for phase identification and structure solution, but still needs further development in order to be as accurate as X-ray diffraction. It is expected that three-dimensional ED methods

A time-focusing Fourier chopper time-of-flight diffractometer for large scattering angles

International Nuclear Information System (INIS)

Heinonen, R.; Hiismaeki, P.; Piirto, A.; Poeyry, H.; Tiitta, A.

1975-01-01

A high-resolution time-of-flight diffractometer utilizing time focusing principles in conjunction with a Fourier chopper is under construction at Otaniemi. The design is an improved version of a test facility which has been used for single-crystal and powder diffraction studies with promising results. A polychromatic neutron beam from a radial beam tube of the FiR 1 reactor, collimated to dia. 70 mm, is modulated by a Fourier chopper (dia. 400 mm) which is placed inside a massive boron-loaded particle board shielding of 900 mm wall thickness. A thin flat sample (5 mm x dia. 80 mm typically) is mounted on a turntable at a distance of 4 m from the chopper, and the diffracted neutrons are counted by a scintillation detector at 4 m distance from the sample. The scattering angle 2theta can be chosen between 90deg and 160deg to cover Bragg angles from 45deg up to 80deg. The angle between the chopper disc and the incident beam direction as well as the angle of the detector surface relative to the diffracted beam can be adjusted between 45deg and 90deg in order to accomplish time-focusing. In our set-up, with equal flight paths from chopper to sample and from sample to detector, the time-focusing conditions are fulfilled when the chopper and the detector are parallel to the sample-plane. The time-of-flight spectrum of the scattered neutrons is measured by the reverse time-of-flight method in which, instead of neutrons, one essentially records the modulation function of the chopper during constant periods preceding each detected neutron. With a Fourier chopper whose speed is varied in a suitable way, the method is equivalent to the conventional Fourier method but the spectrum is obtained directly without any off-line calculations. The new diffractometer is operated automatically by a Super Nova computer which not only accumulates the synthetized diffraction pattern but also controls the chopper speed according to the modulation frequency sweep chosen by the user to obtain a

Combining x-ray diffraction contrast tomography and mesoscale grain growth simulations in strontium titanate: An integrated approach for the investigation of microstructure evolution

DEFF Research Database (Denmark)

Syha, Melanie; Baürer, Michael; Rheinheimer, Wolfgang

2013-01-01

Motivated by the recently reported a growth anomaly in strontium titatate bulk samples1, the microstructure of bulk strontium titanate has been investigated by an integrated approach comprising conventional metallography, three dimensional X-ray diffraction contrast tomography (DCT)2, and the obs......Motivated by the recently reported a growth anomaly in strontium titatate bulk samples1, the microstructure of bulk strontium titanate has been investigated by an integrated approach comprising conventional metallography, three dimensional X-ray diffraction contrast tomography (DCT)2......, and the observation of pore shapes in combination with mesoscale grain growth simulations. The microstructural evolution in strontium titanate has been characterized alternating ex-situ annealing and high energy X-ray DCT measurements, resulting in three dimensional microstructure reconstructions which...

Nanostructure Diffraction Gratings for Integrated Spectroscopy and Sensing

Science.gov (United States)

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.

Experimental technique of stress analyses by neutron diffraction

International Nuclear Information System (INIS)

Sun, Guangai; Chen, Bo; Huang, Chaoqiang

2009-09-01

The structures and main components of neutron diffraction stress analyses spectrometer, SALSA, as well as functions and parameters of each components are presented. The technical characteristic and structure parameters of SALSA are described. Based on these aspects, the choice of gauge volume, method of positioning sample, determination of diffraction plane and measurement of zero stress do are discussed. Combined with the practical experiments, the basic experimental measurement and the related settings are introduced, including the adjustments of components, pattern scattering, data recording and checking etc. The above can be an instruction for stress analyses experiments by neutron diffraction and neutron stress spectrometer construction. (authors)

High-energy X-ray diffraction studies of disordered materials

International Nuclear Information System (INIS)

Kohara, Shinji; Suzuya, Kentaro

2003-01-01

With the arrival of the latest generation of synchrotron sources and the introduction of advanced insertion devices (wigglers and undulators), the high-energy (E≥50 keV) X-ray diffraction technique has become feasible, leading to new approaches in the quantitative study of the structure of disordered materials. High-energy X-ray diffraction has several advantages: higher resolution in real space due to a wide range of scattering vector Q, smaller correction terms (especially the absorption correction), reduction of truncation errors, the feasibility of running under extreme environments, including high-temperatures and high-pressures, and the ability to make direct comparisons between X-ray and neutron diffraction data. Recently, high-energy X-ray diffraction data have been combined with neutron diffraction data from a pulsed source to provide more detailed and reliable structural information than that hitherto available

Inclusive measurement of diffractive deep-inelastic scattering at HERA

International Nuclear Information System (INIS)

Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G.; Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y.; Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N.; Baghdasaryan, A.; Baghdasaryan, S.; Zohrabyan, H.; Barrelet, E.; Bartel, W.; Belov, P.; Brandt, G.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Habib, S.; Haidt, D.; Kleinwort, C.; Kraemer, M.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Nowak, K.; Olsson, J.E.; Pahl, P.; Panagoulias, I.; Papadopoulou, T.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Radescu, V.; Schmitt, S.; Sefkow, F.; Shushkevich, S.; South, D.; Steder, M.; Wuensch, E.; Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B.; Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F.; Boudry, V.; Moreau, F.; Specka, A.; Bozovic-Jelisavcic, I.; Pandurovic, M.; Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Thompson, P.D.; Bruncko, D.; Cerny, V.; Ferencei, J.; Bunyatyan, A.; Bylinkin, A.; Bystritskaya, L.; Fedotov, A.; Lubimov, V.; Ozerov, D.; Rostovtsev, A.; Zhokin, A.; Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E.; Ceccopieri, F.; Delvax, J.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Roosen, R.; Staykova, Z.; Mechelen, P. van; Cerny, K.; Pokorny, B.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Zlebcik, R.; Chekelian, V.; Dossanov, A.; Grindhammer, G.; Kiesling, C.; Coughlan, J.A.; Morris, J.V.; Sankey, D.P.C.; Cvach, J.; Hladky, J.; Reimer, P.; Zalesak, J.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kluge, T.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Daum, K.; Meyer, H.; Diaconu, C.; Hoffmann, D.; Sauvan, E.; Vallee, C.; Dobre, M.; Kogler, R.; Dodonov, V.; Povh, B.; Egli, S.; Hildebrandt, M.; Horisberger, R.; Feltesse, J.; Perez, E.; Schoeffel, L.; Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J.; Grab, C.; Henderson, R.C.W.; Sloan, T.; Hennekemper, E.; Herbst, M.; Krueger, K.; Lendermann, V.; Schultz-Coulon, H.C.; Henschel, H.; Hiller, K.H.; Kostka, P.; Lange, W.; Naumann, T.; Herrera, G.; Lopez-Fernandez, R.; Huber, F.; Pirumov, H.; Sauter, M.; Schoening, A.; Joensson, L.; Jung, H.; Kapichine, M.; Morozov, A.; Nikitin, D.; Palichik, V.; Spaskov, V.; Landon, M.P.J.; Rizvi, E.; Traynor, D.; Martyn, H.U.; Mueller, K.; Robmann, P.; Straumann, U.; Truoel, P.; Stella, B.; Sykora, T.; Tsakov, I.; Wegener, D.

2012-01-01

The diffractive process ep→eXY, where Y denotes a proton or its low mass excitation with M Y 2 ≤ 1600 GeV 2 , the square of the four-momentum transfer at the proton vertex vertical stroke t vertical stroke 2 and the longitudinal momentum fraction of the incident proton carried by the colourless exchange x P P , Q 2 and β=x/x P where x is the Bjorken scaling variable. These measurements are made after selecting diffractive events by demanding a large empty rapidity interval separating the final state hadronic systems X and Y. High statistics measurements covering the data taking periods 1999-2000 and 2004-2007 are combined with previously published results in order to provide a single set of diffractive cross sections from the H1 experiment using the large rapidity gap selection method. The combined data represent a factor between three and thirty increase in statistics with respect to the previously published results. The measurements are compared with predictions from NLO QCD calculations based on diffractive parton densities and from a dipole model. The proton vertex factorisation hypothesis is tested. (orig.)

Overview of diffraction gratings technologies for spaceflight satellites and ground-based telescopes

Science.gov (United States)

Cotel, A.; Liard, A.; Desserouer, F.; Pichon, P.

2017-11-01

The diffraction gratings are widely used in Space-flight satellites for spectrograph instruments or in ground-based telescopes in astronomy. The diffraction gratings are one of the key optical components of such systems and have to exhibit very high optical performances. HORIBA Jobin Yvon S.A.S. (part of HORIBA Group) is in the forefront of such gratings development for more than 40 years. During the past decades, HORIBA Jobin Yvon (HJY) has developed a unique expertise in diffraction grating design and manufacturing processes for holographic, ruled or etched gratings. We will present in this paper an overview of diffraction grating technologies especially designed for space and astronomy applications. We will firstly review the heritage of the company in this field with the space qualification of different grating types. Then, we will describe several key grating technologies developed for specific space or astronomy projects: ruled blazed low groove density plane reflection grating, high-groove density holographic toroidal and spherical grating, and finally transmission Fused Silica Etched (FSE) grism-assembled grating. We will not present the Volume Phase Holographic (VPHG) grating type which is used in Astronomy.

Surface diffusion studies by optical diffraction techniques

International Nuclear Information System (INIS)

Xiao, X.D.

1992-11-01

The newly developed optical techniques have been combined with either second harmonic (SH) diffraction or linear diffraction off a monolayer adsorbate grating for surface diffusion measurement. Anisotropy of surface diffusion of CO on Ni(l10) was used as a demonstration for the second harmonic dim reaction method. The linear diffraction method, which possesses a much higher sensitivity than the SH diffraction method, was employed to study the effect of adsorbate-adsorbate interaction on CO diffusion on Ni(l10) surface. Results showed that only the short range direct CO-CO orbital overlapping interaction influences CO diffusion but not the long range dipole-dipole and CO-NI-CO interactions. Effects of impurities and defects on surface diffusion were further explored by using linear diffraction method on CO/Ni(110) system. It was found that a few percent S impurity can alter the CO diffusion barrier height to a much higher value through changing the Ni(110) surface. The point defects of Ni(l10) surface seem to speed up CO diffusion significantly. A mechanism with long jumps over multiple lattice distance initiated by CO filled vacancy is proposed to explain the observed defect effect

Diffractive flat panel solar concentrators of a novel design.

Science.gov (United States)

de Jong, Ties M; de Boer, Dick K G; Bastiaansen, Cees W M

2016-07-11

A novel design for a flat panel solar concentrator is presented which is based on a light guide with a grating applied on top that diffracts light into total internal reflection. By combining geometrical and diffractive optics the geometrical concentration ratio is optimized according to the principles of nonimaging optics, while the thickness of the device is minimized due to the use of total internal reflection.

Engineering related neutron diffraction measurements probing strains, texture and microstructure

Energy Technology Data Exchange (ETDEWEB)

Clausen, Bjorn [Los Alamos National Laboratory; Brown, Donald W [Los Alamos National Laboratory; Tome, Carlos N [Los Alamos National Laboratory; Balogh, Levente [Los Alamos National Laboratory; Vogel, Sven C [Los Alamos National Laboratory

2010-01-01

Neutron diffraction has been used for engineering applications for nearly three decades. The basis of the technique is powder diffraction following Bragg's Law. From the measured diffraction patterns information about internal, or residual, strain can be deduced from the peak positions, texture information can be extracted from the peak intensities, and finally the peak widths can provide information about the microstructure, e.g. dislocation densities and grain sizes. The strains are measured directly from changes in lattice parameters, however, in many cases it is non-trivial to determine macroscopic values of stress or strain from the measured data. The effects of intergranular strains must be considered, and combining the neutron diffraction measurements with polycrystal deformation modeling has proven invaluable in determining the overall stress and strain values of interest in designing and dimensioning engineering components. Furthelmore, the combined use of measurements and modeling has provided a tool for elucidating basic material properties, such as critical resolved shear stresses for the active deformation modes and their evolution as a function of applied deformation.

Diffraction Techniques in Structural Biology

Science.gov (United States)

Egli, Martin

2016-01-01

A detailed understanding of chemical and biological function and the mechanisms underlying the molecular activities ultimately requires atomic-resolution structural data. Diffraction-based techniques such as single-crystal X-ray crystallography, electron microscopy, and neutron diffraction are well established and they have paved the road to the stunning successes of modern-day structural biology. The major advances achieved in the last 20 years in all aspects of structural research, including sample preparation, crystallization, the construction of synchrotron and spallation sources, phasing approaches, and high-speed computing and visualization, now provide specialists and nonspecialists alike with a steady flow of molecular images of unprecedented detail. The present unit combines a general overview of diffraction methods with a detailed description of the process of a single-crystal X-ray structure determination experiment, from chemical synthesis or expression to phasing and refinement, analysis, and quality control. For novices it may serve as a stepping-stone to more in-depth treatises of the individual topics. Readers relying on structural information for interpreting functional data may find it a useful consumer guide. PMID:27248784

ADVANTAGES OF DIFFRACTIVE OPTICAL ELEMENTS APPLICATION IN SIMPLE OPTICAL IMAGING SYSTEMS

Directory of Open Access Journals (Sweden)

N. D. Zoric

2015-01-01

Full Text Available The paper deals with the influence of diffractive optical elements on the optical aberrations. The correction of optical aberrations was investigated in the simple optical systems with one and two lenses (singlet and doublet. The advantages of diffractive optical elements are their ability to generate arbitrary complex wave fronts from a piece of optical material that is essentially flat. The optical systems consisting of the standard surfaces were designed and optimized by using the same starting points. Further, the diffractive and aspheric surfaces were introduced into the developed systems. The resulting hybrid systems were optimized. To compare the complicity of the development of narrow field systems and wide field optical systems, the optimization has been done separately for these two types of the instruments. The optical systems were designed by using special Optical Design Software. Тhe characteristics of designed diffractive surfaces were controlled in Software DIFSYS 2.30. Due to the application of diffractive optical elements the longitudinal chromatic aberration was 5 times reduced for the narrow field systems. The absolute value of Seidel coefficient related to the spherical aberration was reduced in the range of 0.03. Considering that diffractive optical elements have the known disadvantages, like possible parasitic diffraction orders and probable decrease of the transmission, we also developed and analyzed the optical systems with combined aspheric and diffractive surfaces. A combination of the aspheric and diffractive surfaces in the optical disk system of the disk reading lens, gave cutting down of the longitudinal color aberrations almost 15 times on-axis, comparing to the lens consisting of the aspherical and standard surfaces. All of the designed diffractive optical elements possess the parameters within the fabrication limits.

Report from the neutron diffraction work group

International Nuclear Information System (INIS)

1978-08-01

This progress report of the neutron diffraction group at the Hahn Meitner Institute in Berlin comprises the following contributions: Three-dimensional critical properties of CsNiF 3 around the Neel point; Spin waves in CsNiF 3 with an applied magnetic field; Solitons in CsNiF 3 : Their experimental evidence and their thermodynamics; Neutron diffraction study of DAG at very low temperatures and in external magnetic field; Neutron diffraction investigation of tricritical behaviour in DyPO 4 ; Crystalline modifications and structural phase transitions of NaOH; Gitterdynamik von Cerhydrid; Investigation of the ferroelectric-ferroelastic phase transition in KH 2 PO 4 and RbH 2 PO 4 by means of γ-ray diffractometry; A γ-ray diffractometer for systematic measurements of absolute structure factors; Electron density in pyrite by combined γ-ray and neutron diffraction measurements: Thermal parameters from short wavelength neutron data; Accurate determination of temperature parameters from neutron diffraction data: Direct observation of the thermal diffuse scattering from silicon using perfect crystals; A Compton spectrometer for momentum density studies using 412 keV γ-radiation; Investigation of the electronic structure of Niobiumhydrides by means of gamma-ray Compton scattering; Interpretation of Compton profile data in position space; High resolution neutron scattering measurements on single crystals using a horizontally bent monochromator and a multidetecter; Statistical analysis of neutron diffraction studies of proteins. (orig.) [de

Revisit to diffraction anomalous fine structure

International Nuclear Information System (INIS)

Kawaguchi, T.; Fukuda, K.; Tokuda, K.; Shimada, K.; Ichitsubo, T.; Oishi, M.; Mizuki, J.; Matsubara, E.

2014-01-01

The diffraction anomalous fine structure method has been revisited by applying this measurement technique to polycrystalline samples and using an analytical method with the logarithmic dispersion relation. The diffraction anomalous fine structure (DAFS) method that is a spectroscopic analysis combined with resonant X-ray diffraction enables the determination of the valence state and local structure of a selected element at a specific crystalline site and/or phase. This method has been improved by using a polycrystalline sample, channel-cut monochromator optics with an undulator synchrotron radiation source, an area detector and direct determination of resonant terms with a logarithmic dispersion relation. This study makes the DAFS method more convenient and saves a large amount of measurement time in comparison with the conventional DAFS method with a single crystal. The improved DAFS method has been applied to some model samples, Ni foil and Fe 3 O 4 powder, to demonstrate the validity of the measurement and the analysis of the present DAFS method

Nutrition, endocrinology, and body composition during space flight

Science.gov (United States)

Lane, H. W.; Gretebeck, R. J.; Smith, S. M.

1998-01-01

Space flight induces endocrine changes that perturb metabolism. This altered metabolism affects both the astronauts' body composition and the nutritional requirements necessary to maintain their health. During the last 25 years, a combination of studies conducted on Skylab (the first U.S. space laboratory), U.S. Shuttle flights, and Soviet and Russian flights provides a range of data from which general conclusions about energy and protein requirements can be drawn. We have reviewed the endocrine data from those studies and related it to changes in body composition. From these data it appears that protein and energy intake of astronauts are similar to those on Earth. However, a combination of measures, including exercise, appropriate diet, and, potentially, drugs, is required to provide the muscle health needed for long duration space flight.

Reconstructing an icosahedral virus from single-particle diffraction experiments

Science.gov (United States)

Saldin, D. K.; Poon, H.-C.; Schwander, P.; Uddin, M.; Schmidt, M.

2011-08-01

The first experimental data from single-particle scattering experiments from free electron lasers (FELs) are now becoming available. The first such experiments are being performed on relatively large objects such as viruses, which produce relatively low-resolution, low-noise diffraction patterns in so-called ``diffract-and-destroy'' experiments. We describe a very simple test on the angular correlations of measured diffraction data to determine if the scattering is from an icosahedral particle. If this is confirmed, the efficient algorithm proposed can then combine diffraction data from multiple shots of particles in random unknown orientations to generate a full 3D image of the icosahedral particle. We demonstrate this with a simulation for the satellite tobacco necrosis virus (STNV), the atomic coordinates of whose asymmetric unit is given in Protein Data Bank entry 2BUK.

Time-dependent Bragg diffraction by multilayer gratings

International Nuclear Information System (INIS)

André, Jean-Michel; Jonnard, Philippe

2016-01-01

Time-dependent Bragg diffraction by multilayer gratings working by reflection or by transmission is investigated. The study is performed by generalizing the time-dependent coupled-wave theory previously developed for one-dimensional photonic crystals (André J-M and Jonnard P 2015 J. Opt. 17 085609) and also by extending the Takagi–Taupin approach of the dynamical theory of diffraction. The indicial response is calculated. It presents a time delay with a transient time that is a function of the extinction length for reflection geometry and of the extinction length combined with the thickness of the grating for transmission geometry. (paper)

High pressure sample container for thermal neutron spectroscopy and diffraction on strongly scattering fluids

International Nuclear Information System (INIS)

Verkerk, P.; Pruisken, A.M.M.

1979-01-01

A description is presented of the construction and performance of a container for thermal neutron scattering on a fluid sample with about 1.5 cm -1 macroscopic cross section (neglecting absorption). The maximum pressure is about 900 bar. The container is made of 5052 aluminium capillary with inner diameter 0.75 mm and wall thickness 0.25 mm; it covers a neutron beam with a cross section of 9 X 2.5 cm 2 . The container has been successfully used in neutron diffraction and time-of-flight experiments on argon-36 at 120 K and several pressures up to 850 bar. It is shown that during these measurements the temperature gradient over the sample as well as the error in the absolute temperature were both less than 0.05 K. Subtraction of the Bragg peaks due to container scattering in diffraction experiments may be dfficult, but seems feasible because of the small amount of aluminium in the neutron beam. Correction for container scattering and multiple scattering in time-of-flight experiments may be difficult only in the case of coherently scattering samples and small scattering angles. (Auth.)

Diffraction theory

NARCIS (Netherlands)

Bouwkamp, C.J.

1954-01-01

A critical review is presented of recent progress in classical diffraction theory. Both scalar and electromagnetic problems are discussed. The report may serve as an introduction to general diffraction theory although the main emphasis is on diffraction by plane obstacles. Various modifications of

Single-diffractive Drell-Yan pair production at the LHC

Energy Technology Data Exchange (ETDEWEB)

Ceccopieri, Federico Alberto [Universita degli Studi di Perugia, Dipartimento di Fisica e Geologia, Perugia (Italy); Universite de Liege, IFPA, Liege (Belgium); INFN, Sezione di Perugia (Italy)

2017-01-15

We present predictions for single-diffractive low-mass Drell-Yan pair production in pp collisions at the LHC at √(s) = 13 TeV. Predictions are obtained adopting a factorised form for the relevant cross sections and are based on a new set of diffractive parton distributions resulting from the QCD analysis of combined HERA leading proton data. We discuss a number of observables useful to characterise the expected factorisation breaking effects. (orig.)

Dedicated software for diffractive optics design and simulation

International Nuclear Information System (INIS)

Firsov, A; Brzhezinskaya, M; Erko, A; Firsov, A; Svintsov, A

2013-01-01

An efficient software package for the structure design and simulation of imaging properties of diffraction optical elements has been developed. It operates with point source and consists of: the ZON software, to calculate the structure of an optical element in transmission and reflection; the KRGF software, to simulate the diffraction properties of an ideal optical element with point source; the DS software, to calculate the diffraction properties by taking into consideration material and shadowing effects. Optional software allows simulation with a real non-point source. Zone plate thickness profile, source shape as well as substrate curvature are considered in this calculation. This is especially important for the diffractive focusing elements and gratings at a total external reflection, given that the lateral size of the structure can be up to 1 m. The program package can be used in combination with the Nanomaker software to prepare data for ion and e-beam surface modifications and corrections.

Mapping residual and internal stress in materials by neutron diffraction

International Nuclear Information System (INIS)

Withers, Ph.J.

2007-01-01

Neutron diffraction provides one of the few means of mapping residual stresses deep within the bulk of materials and components. This article reviews the basic scientific methodology by which internal strains and stresses are inferred from recorded diffraction peaks. Both conventional angular scans and time-of-flight measurements are reviewed and compared. Their complementarity with analogous synchrotron X-ray methods is also highlighted. For measurements to be exploited in structural integrity calculations underpinning the safe operation of engineering components, measurement standards have been defined and the major findings are summarised. Examples are used to highlight the unique capabilities of the method showing how it can provide insights ranging from the basic physics of slip mechanisms in hexagonal polycrystalline materials, through the materials optimisation of stress induced transformations in smart nano-materials, to the industrial introduction of novel friction welding processes exploiting stress residual measurements transferred from prototype sub-scale tests to the joining of full-scale aero-engine assemblies. (author)

X – ray and neutron diffraction of TiAl alloys

International Nuclear Information System (INIS)

Valkov, Stefan; Petrov, Peter; Neov, Dimitar; Beskrovny, Anatoly; Kozlenko, Denis

2015-01-01

TiAl alloys were prepared by electron beam hybrid method. Composite Ti-Al film, from composite target, was deposited on Ti substrate by electron beam evaporation, followed by electron beam treatment with scanning electron beam. Experiments were made using Leybold Heraus (EWS 300/ 15 - 60) with the following technological parameters : accelerating voltage U = 60kV; beam current I=40 mA, speed of movement of specimens V=5 cm/s, current of the focusing lens If =512mA, specimen distance D0 = 38cm. X- ray and neutron diffraction methods were used to determine the phase composition on the surface and at the volume, respectively. Time of flight neutron diffraction study of TiAl specimens was performed on DN-2 diffractometer at fast pulsed IBR-2 reactor in FLNP JINR (Dubna, Russia).We found that intermetallic TiAl phases were successfully obtained on the surface, as well as in the volume.

Evaluation of Poisson's ratio and Young's modulus of nitride films by combining grazing incidence X-ray diffraction and laser curvature techniques

International Nuclear Information System (INIS)

Chen, H.-Y.; Chen, J.-H.; Lu, F.-H.

2007-01-01

Measurements of Poisson's ratio and the Young's modulus of thin films have been problematic. In this work, evaluation of both Poisson's ratio and Young's modulus is conducted using grazing incidence X-ray diffraction combined with measurement of the induced stress. Poisson's ratio was evaluated from analysis of the X-ray diffraction data to obtain a strain-cos 2 α.sin 2 ψ plot. Moreover, the Young's modulus of the films could be also calculated from that plot as well as from the residual stress, which could be determined by a measurement of stress induced substrate curvature. The ternary nitride TiAlN is used as a model system for the evaluation. The films, prepared by cathodic arc plasma deposition, exhibited a strong (111) preferred orientation and a composition corresponding to Ti 0.6 Al 0.4 N. The measured Poisson's ratio and the Young's modulus of the films were 0.143 ± 0.003 and 310 ± 20 GPa, respectively, which are comparable to those reported in the literature

Combined Approach for the Structural Characterization of Alkali Fluoroscandates: Solid-State NMR, Powder X-ray Diffraction, and Density Functional Theory Calculations.

Science.gov (United States)

Rakhmatullin, Aydar; Polovov, Ilya B; Maltsev, Dmitry; Allix, Mathieu; Volkovich, Vladimir; Chukin, Andrey V; Boča, Miroslav; Bessada, Catherine

2018-02-05

The structures of several fluoroscandate compounds are presented here using a characterization approach combining powder X-ray diffraction and solid-state NMR. The structure of K 5 Sc 3 F 14 was fully determined from Rietveld refinement performed on powder X-ray diffraction data. Moreover, the local structures of NaScF 4 , Li 3 ScF 6 , KSc 2 F 7 , and Na 3 ScF 6 compounds were studied in detail from solid-state 19 F and 45 Sc NMR experiments. The 45 Sc chemical shift ranges for six- and seven-coordinated scandium environments were defined. The 19 F chemical shift ranges for bridging and terminal fluorine atoms were also determined. First-principles calculations of the 19 F and 45 Sc NMR parameters were carried out using plane-wave basis sets and periodic boundary conditions (CASTEP), and the results were compared with the experimental data. A good agreement between the calculated shielding constants and experimental chemical shifts was obtained. This demonstrates the good potential of computational methods in spectroscopic assignments of solid-state 45 Sc NMR spectroscopy.

Combined resistive and laser heating technique for in situ radial X-ray diffraction in the diamond anvil cell at high pressure and temperature

Energy Technology Data Exchange (ETDEWEB)

Miyagi, Lowell [Department of Geology and Geophysics, University of Utah, Salt Lake City, Utah 84112 (United States); Department of Earth Sciences, Montana State University, Bozeman, Montana 59717 (United States); Kanitpanyacharoen, Waruntorn; Kaercher, Pamela; Wenk, Hans-Rudolf; Alarcon, Eloisa Zepeda [Department of Earth and Planetary Science, University of California, Berkeley, California 94720 (United States); Raju, Selva Vennila [Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States); HiPSEC, Department of Physics, University of Nevada, Las Vegas, Nevada 89154 (United States); Knight, Jason; MacDowell, Alastair [Advanced Light Source, Lawrence Berkeley Laboratory, Berkeley, California 94720 (United States); Williams, Quentin [Department of Earth and Planetary Science, University of California, Santa Cruz, California 95064 (United States)

2013-02-15

To extend the range of high-temperature, high-pressure studies within the diamond anvil cell, a Liermann-type diamond anvil cell with radial diffraction geometry (rDAC) was redesigned and developed for synchrotron X-ray diffraction experiments at beamline 12.2.2 of the Advanced Light Source. The rDAC, equipped with graphite heating arrays, allows simultaneous resistive and laser heating while the material is subjected to high pressure. The goals are both to extend the temperature range of external (resistive) heating and to produce environments with lower temperature gradients in a simultaneously resistive- and laser-heated rDAC. Three different geomaterials were used as pilot samples to calibrate and optimize conditions for combined resistive and laser heating. For example, in Run1, FeO was loaded in a boron-mica gasket and compressed to 11 GPa then gradually resistively heated to 1007 K (1073 K at the diamond side). The laser heating was further applied to FeO to raise temperature to 2273 K. In Run2, Fe-Ni alloy was compressed to 18 GPa and resistively heated to 1785 K (1973 K at the diamond side). The combined resistive and laser heating was successfully performed again on (Mg{sub 0.9}Fe{sub 0.1})O in Run3. In this instance, the sample was loaded in a boron-kapton gasket, compressed to 29 GPa, resistive-heated up to 1007 K (1073 K at the diamond side), and further simultaneously laser-heated to achieve a temperature in excess of 2273 K at the sample position. Diffraction patterns obtained from the experiments were deconvoluted using the Rietveld method and quantified for lattice preferred orientation of each material under extreme conditions and during phase transformation.

Multiplexing schemes for an achromatic programmable diffractive lens

Energy Technology Data Exchange (ETDEWEB)

Millan, M S; Perez-Cabre, E; Oton, J [Technical University of Catalonia, Dep. Optics and Optometry, Terrassa-Barcelona, 08222 (Spain)], E-mail: millan@oo.upc.edu

2008-11-01

A multiplexed programmable diffractive lens, displayed on a pixelated liquid crystal device under broadband illumination, is proposed to compensate for the severe chromatic aberration that affects diffractive elements. The proposed lens is based on multiplexing a set of sublenses with a common focal length for different wavelengths. We consider different types of integration of the optical information (spatial only, temporal only and hybrid spatial-temporal) combined with a proper selection of the spectral bandwidth. The properties and limits of the achromatic programmable multiplexed lens are described. Experimental results are presented and discussed.

Multiplexing schemes for an achromatic programmable diffractive lens

International Nuclear Information System (INIS)

Millan, M S; Perez-Cabre, E; Oton, J

2008-01-01

A multiplexed programmable diffractive lens, displayed on a pixelated liquid crystal device under broadband illumination, is proposed to compensate for the severe chromatic aberration that affects diffractive elements. The proposed lens is based on multiplexing a set of sublenses with a common focal length for different wavelengths. We consider different types of integration of the optical information (spatial only, temporal only and hybrid spatial-temporal) combined with a proper selection of the spectral bandwidth. The properties and limits of the achromatic programmable multiplexed lens are described. Experimental results are presented and discussed.

Anisotropic thermal expansion of MgSiN2 from 10 to 300 K as measured by neutron diffraction

NARCIS (Netherlands)

Bruls, R.J.; Hintzen, H.T.J.M.; Metselaar, R.; Loong, C.K.

2000-01-01

The lattice parameters of orthorhombic MgSiN2 as a function of the temperature have been determined from time-of-flight neutron powder diffraction. The results indicate that MgSiN2, just like several other adamantine-type crystals, exhibits a relatively small thermal expansion coefficient at low

A 3D implementation of ray tracing combined with diffraction on facets: Verification and a potential application

International Nuclear Information System (INIS)

Clarke, Adrian J.M.; Hesse, Evelyn; Ulanowski, Zbigniew; Kaye, Paul H.

2006-01-01

A 3D implementation of a new model of light scattering applicable to dielectric faceted objects is introduced. The model combines standard geometric optics with diffraction on individual facets. It can be applied to any faceted geometry. The model adds no significant computational overheads to classical geometric optics yet provides much improved results. Initial results for long hexagonal columns are compared to SVM and appear favourable. 2D scattering patterns are calculated for a hexagonal column in a fixed orientation and compared to those created by ice analogue crystals in the laboratory with close agreement. The comparison includes the observation of a guided wave propagating along the length of the column. The new model is then applied to a selection of geometries to illustrate how it could be used to aid particle characterization, particularly in the case of cirrus ice

Combining endoscopic ultrasound with Time-Of-Flight PET: The EndoTOFPET-US Project

CERN Document Server

Frisch, Benjamin

2013-01-01

The EndoTOFPET-US collaboration develops a multimodal imaging technique for endoscopic exams of the pancreas or the prostate. It combines the benefits of high resolution metabolic imaging with Time-Of-Flight Positron Emission Tomography (TOF PET) and anatomical imaging with ultrasound (US). EndoTOFPET-US consists of a PET head extension for a commercial US endoscope and a PET plate outside the body in coincidence with the head. The high level of miniaturization and integration creates challenges in fields such as scintillating crystals, ultra-fast photo-detection, highly integrated electronics, system integration and image reconstruction. Amongst the developments, fast scintillators as well as fast and compact digital SiPMs with single SPAD readout are used to obtain the best coincidence time resolution (CTR). Highly integrated ASICs and DAQ electronics contribute to the timing performances of EndoTOFPET. In view of the targeted resolution of around 1 mm in the reconstructed image, we present a prototype dete...

Reuse fo a Cold War Surveillance Drone to Flight Test a NASA Rocket Based Combined Cycle Engine

Science.gov (United States)

Brown, T. M.; Smith, Norm

1999-01-01

Plans for and early feasibility investigations into the modification of a Lockheed D21B drone to flight test the DRACO Rocket Based Combined Cycle (RBCC) engine are discussed. Modifications include the addition of oxidizer tanks, modern avionics systems, actuators, and a vehicle recovery system. Current study results indicate that the D21B is a suitable candidate for this application and will allow demonstrations of all DRACO engine operating modes at Mach numbers between 0.8 and 4.0. Higher Mach numbers may be achieved with more extensive modification. Possible project risks include low speed stability and control, and recovery techniques.

Helicopter Flight Procedures for Community Noise Reduction

Science.gov (United States)

Greenwood, Eric

2017-01-01

A computationally efficient, semiempirical noise model suitable for maneuvering flight noise prediction is used to evaluate the community noise impact of practical variations on several helicopter flight procedures typical of normal operations. Turns, "quick-stops," approaches, climbs, and combinations of these maneuvers are assessed. Relatively small variations in flight procedures are shown to cause significant changes to Sound Exposure Levels over a wide area. Guidelines are developed for helicopter pilots intended to provide effective strategies for reducing the negative effects of helicopter noise on the community. Finally, direct optimization of flight trajectories is conducted to identify low noise optimal flight procedures and quantify the magnitude of community noise reductions that can be obtained through tailored helicopter flight procedures. Physically realizable optimal turns and approaches are identified that achieve global noise reductions of as much as 10 dBA Sound Exposure Level.

Effect of substrate material selection on polychromatic integral diffraction efficiency for multilayer diffractive optics in oblique incident situation

Science.gov (United States)

Zhang, Bo; Cui, Qingfeng; Piao, Mingxu

2018-05-01

The effect of substrate material selection for multilayer diffractive optical elements (MLDOEs) on polychromatic integral diffraction efficiency (PIDE) is studied in the oblique incident situation. A mathematical model of substrate material selection is proposed to obtain the high PIDE with large incident angle. The extended expression of the microstructure heights with consideration of incident angle is deduced to calculate the PIDE difference Δ η bar(λ) for different substrate material combinations. The smaller value of Δ η bar(λ) indicates the more optimal substrate material combination in a wide incident angle range. Based on the deduced mathematical model, different MLDOEs are analyzed in visible and infrared wavebands. The results show that the three-layer DOEs can be applied in larger incident angle situation than the double-layer DOEs in visible waveband. When the two substrate materials are the same, polycarbonate (PC) is more reasonable than poly(methyl methacrylate) (PMMA) as the middle filling optical material for the three-layer DOEs. In the infrared waveband, the PIDE decreases in the LWIR are obviously smaller than that in the MWIR for the same substrate material combination, and the PIDE cannot be calculated when the incident angle larger than critical angle. The analysis results can be used to guide the hybrid optical system design with MLDOEs.

Multiwavelength anomalous diffraction and diffraction anomalous fine structure to study composition and strain of semiconductor nano structures

International Nuclear Information System (INIS)

Favre-Nicolin, V.; Proietti, M.G.; Leclere, C.; Renevier, H.; Katcho, N.A.; Richard, M.I.

2012-01-01

The aim of this paper is to illustrate the use of Multi-Wavelength Anomalous Diffraction (MAD) and Diffraction Anomalous Fine Structure (DAFS) spectroscopy for the study of structural properties of semiconductor nano-structures. We give a brief introduction on the basic principles of these techniques providing a detailed bibliography. Then we focus on the data reduction and analysis and we give specific examples of their application on three different kinds of semiconductor nano-structures: Ge/Si nano-islands, AlN capped GaN/AlN Quantum Dots and AlGaN/AlN Nano-wires. We show that the combination of MAD and DAFS is a very powerful tool to solve the structural problem of these materials of high technological impact. In particular, the effects of composition and strain on diffraction are disentangled and composition can be determined in a reliable way, even at the interface between nano-structure and substrate. We show the great possibilities of this method and give the reader the basic tools to undertake its use. (authors)

Envelope Protection for In-Flight Ice Contamination

Science.gov (United States)

Gingras, David R.; Barnhart, Billy P.; Ranaudo, Richard J.; Ratvasky, Thomas P.; Morelli, Eugene A.

2010-01-01

Fatal loss-of-control (LOC) accidents have been directly related to in-flight airframe icing. The prototype system presented in this paper directly addresses the need for real-time onboard envelope protection in icing conditions. The combinations of a-priori information and realtime aerodynamic estimations are shown to provide sufficient input for determining safe limits of the flight envelope during in-flight icing encounters. The Icing Contamination Envelope Protection (ICEPro) system has been designed and implemented to identify degradations in airplane performance and flying qualities resulting from ice contamination and provide safe flight-envelope cues to the pilot. Components of ICEPro are described and results from preliminary tests are presented.

Suspended DNA structural characterization by TEM diffraction

KAUST Repository

Marini, Monica

2017-12-01

In this work, micro-fabrication, super-hydrophobic properties and a physiologically compatible preparation step are combined and tailored to obtain background free biological samples to be investigated by Transmission Electron Microscopy (TEM) diffraction technique. The validation was performed evaluating a well-known parameter such as the DNA interbases value. The diffraction spacing measured is in good agreement with those obtained by HRTEM direct metrology and by traditional X-Ray diffraction. This approach addresses single molecule studies in a simplified and reproducible straightforward way with respect to more conventional and widely used techniques. In addition, it overcomes the need of long and elaborated samples preparations: the sample is in its physiological environment and the HRTEM data acquisition occurs without any background interference, coating, staining or additional manipulation. The congruence in the results reported in this paper makes the application of this approach extremely promising towards those molecules for which crystallization remains a hurdle, such as cell membrane proteins and fibrillar proteins.

Suspended DNA structural characterization by TEM diffraction

KAUST Repository

Marini, Monica; Allione, Marco; Lopatin, Sergei; Moretti, Manola; Giugni, Andrea; Torre, Bruno; Di Fabrizio, Enzo M.

2017-01-01

In this work, micro-fabrication, super-hydrophobic properties and a physiologically compatible preparation step are combined and tailored to obtain background free biological samples to be investigated by Transmission Electron Microscopy (TEM) diffraction technique. The validation was performed evaluating a well-known parameter such as the DNA interbases value. The diffraction spacing measured is in good agreement with those obtained by HRTEM direct metrology and by traditional X-Ray diffraction. This approach addresses single molecule studies in a simplified and reproducible straightforward way with respect to more conventional and widely used techniques. In addition, it overcomes the need of long and elaborated samples preparations: the sample is in its physiological environment and the HRTEM data acquisition occurs without any background interference, coating, staining or additional manipulation. The congruence in the results reported in this paper makes the application of this approach extremely promising towards those molecules for which crystallization remains a hurdle, such as cell membrane proteins and fibrillar proteins.

Effectiveness of cognitive behavioral therapy integrated with systematic desensitization, cognitive behavioral therapy combined with eye movement desensitization and reprocess­ing therapy, and cognitive behavioral therapy combined with virtual reality exposure therapy methods in the treatment of flight anxiety: a randomized trial

Directory of Open Access Journals (Sweden)

Triscari MT

2015-10-01

Full Text Available Maria Teresa Triscari,1 Palmira Faraci,2 Dario Catalisano,3 Valerio D’Angelo,1 Viviana Urso1 1Laboratory for Psychosomatic Disorders, Local Health Trust, Palermo, Italy; 2Faculty of Human and Social Sciences, University of Enna “Kore”, Enna, Italy; 3Italian Flight Safety Committee, Aeroporto di Fiumicino, Fiumicino (RM, Italy Abstract: The purpose of the research was to compare the effectiveness of the following treatment methods for fear of flying: cognitive behavioral therapy (CBT integrated with systematic desensitization, CBT combined with eye movement desensitization and reprocessing therapy, and CBT combined with virtual reality exposure therapy. Overall, our findings have proven the efficacy of all interventions in reducing fear of flying in a pre- to post-treatment comparison. All groups showed a decrease in flight anxiety, suggesting the efficiency of all three treatments in reducing self-report measures of fear of flying. In particular, our results indicated significant improvements for the treated patients using all the treatment programs, as shown not only by test scores but also by participation in the post-treatment flight. Nevertheless, outcome measures maintained a significant effect at a 1-year follow-up. In conclusion, combining CBT with both the application of eye movement desensitization and reprocessing treatment and the virtual stimuli used to expose patients with aerophobia seemed as efficient as traditional cognitive behavioral treatments integrated with systematic desensitization. Keywords: flight anxiety, fear of flying, aerophobia, cognitive behavioral therapy, EMDR, VRET 

Vectorial diffraction properties of THz vortex Bessel beams.

Science.gov (United States)

Wu, Zhen; Wang, Xinke; Sun, Wenfeng; Feng, Shengfei; Han, Peng; Ye, Jiasheng; Yu, Yue; Zhang, Yan

2018-01-22

A vortex Bessel beam combines the merits of an optical vortex and a Bessel beam, including a spiral wave front and a non-diffractive feature, which has immense application potentials in optical trapping, optical fabrication, optical communications, and so on. Here, linearly and circularly polarized vortex Bessel beams in the terahertz (THz) frequency range are generated by utilizing a THz quarter wave plate, a spiral phase plate, and Teflon axicons with different opening angles. Taking advantage of a THz focal-plane imaging system, vectorial diffraction properties of the THz vortex Bessel beams are comprehensively characterized and discussed, including the transverse (Ex, Ey) and longitudinal (Ez) polarization components. The experimental phenomena are accurately simulated by adopting the vectorial Rayleigh diffraction integral. By varying the opening angle of the axicon, the characteristic parameters of these THz vortex Bessel beams are exhibited and compared, including the light spot size, the diffraction-free range, and the phase evolution process. This work provides the precise experimental and theoretical bases for the comprehension and application of a THz vortex Bessel beam.

Diffractive optics and nanophotonics resolution below the diffraction limit

CERN Document Server

Minin, Igor

2016-01-01

In this book the authors present several examples of techniques used to overcome the Abby diffraction limit using flat and 3D diffractive optical elements, photonic crystal lenses, photonic jets, and surface plasmon diffractive optics. The structures discussed can be used in the microwave and THz range and also as scaled models for optical frequencies. Such nano-optical microlenses can be integrated, for example, into existing semiconductor heterostructure platforms for next-generation optoelectronic applications. Chapter 1 considers flat diffractive lenses and innovative 3D radiating structures including a conical millimeter-wave Fresnel zone plate (FZP) lens proposed for subwavelength focusing. In chapter 2 the subwavelength focusing properties of diffractive photonic crystal lenses are considered and it is shown that at least three different types of photonic crystal lens are possible.  With the aim of achieving subwavelength focusing, in chapter 3 an alternative mechanism to produce photonic jets at Tera...

Measurement of residual stress fields in FHPP welding: a comparison between DSPI combined with hole-drilling and neutron diffraction

Science.gov (United States)

Viotti, Matias R.; Albertazzi, Armando; Staron, Peter; Pisa, Marcelo

2013-04-01

This paper shows a portable device to measure mainly residual stress fields outside the optical bench. This system combines the traditional hole drilling technique with Digital Speckle Pattern Interferometry. The novel feature of this device is the high degree of compaction since only one base supports simultaneously the measurement module and the hole-drilling device. The portable device allows the measurement of non-uniform residual stresses in accordance with the ASTM standard. In oil and gas offshore industries, alternative welding procedures among them, the friction hydro pillar processing (FHPP) is highlighted and nowadays is an important maintenance tool since it has the capability to produce structure repairs without risk of explosions. In this process a hole is drilled and filled with a consumable rod of the same material. The rod, which could be cylindrical or conical, is rotated and pressed against the hole, leading to frictional heating. In order to assess features about the residual stress distribution generated by the weld into the rod as well as into the base material around the rod, welded samples were evaluated by neutron diffraction and by the hole drilling technique having a comparison between them. For the hole drilling technique some layers were removed by using electrical discharge machining (EDM) after diffraction measurements in order to assess the bulk stress distribution. Results have shown a good agreement between techniques.

Inclusive measurement of diffractive deep-inelastic scattering at HERA

Energy Technology Data Exchange (ETDEWEB)

Aaron, F.D. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Bucharest Univ. (Romania). Faculty of Physics; Alexa, C. [National Institute for Physics and Nuclear Engineering (NIPNE), Bucharest (Romania); Andreev, V. [Lebedev Physical Institute, Moscow (RU)] (and others)

2012-03-15

The diffractive process ep {yields} eXY, where Y denotes a proton or its low mass excitation with M{sub Y}<1.6 GeV, is studied with the H1 experiment at HERA. The analysis is restricted to the phase space region of the photon virtuality 3{<=} Q{sup 2} {<=}1600 GeV{sup 2}, the square of the four-momentum transfer at the proton vertex vertical stroke t vertical stroke <1.0 GeV{sup 2} and the longitudinal momentum fraction of the incident proton carried by the colourless exchange x{sub P}<0.05. Triple differential cross sections are measured as a function of x{sub P}, Q{sup 2} and {beta}=x/x{sub P} where x is the Bjorken scaling variable. These measurements are made after selecting diffractive events by demanding a large empty rapidity interval separating the final state hadronic systems X and Y. High statistics measurements covering the data taking periods 1999-2000 and 2004-2007 are combined with previously published results in order to provide a single set of diffractive cross sections from the H1 experiment using the large rapidity gap selection method. The combined data represent a factor between three and thirty increase in statistics with respect to the previously published results. The measurements are compared with predictions from NLO QCD calculations based on diffractive parton densities and from a dipole model. The proton vertex factorisation hypothesis is tested. (orig.)

Inclusive measurement of diffractive deep-inelastic scattering at HERA

Energy Technology Data Exchange (ETDEWEB)

Aaron, F.D.; Alexa, C.; Rotaru, M.; Stoicea, G.; Andreev, V.; Belousov, A.; Eliseev, A.; Fomenko, A.; Gogitidze, N.; Lebedev, A.; Malinovski, E.; Rusakov, S.; Shtarkov, L.N.; Soloviev, Y.; Vazdik, Y.; Backovic, S.; Dubak, A.; Lastovicka-Medin, G.; Picuric, I.; Raicevic, N.; Baghdasaryan, A.; Baghdasaryan, S.; Zohrabyan, H.; Barrelet, E.; Bartel, W.; Belov, P.; Brandt, G.; Brinkmann, M.; Britzger, D.; Campbell, A.J.; Eckerlin, G.; Elsen, E.; Felst, R.; Fischer, D.J.; Fleischer, M.; Gayler, J.; Ghazaryan, S.; Glazov, A.; Gouzevitch, M.; Grebenyuk, A.; Habib, S.; Haidt, D.; Kleinwort, C.; Kraemer, M.; Levonian, S.; Lipka, K.; List, B.; List, J.; Lobodzinski, B.; Meyer, A.B.; Meyer, J.; Niebuhr, C.; Nowak, K.; Olsson, J.E.; Pahl, P.; Panagoulias, I.; Papadopoulou, T.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Radescu, V.; Schmitt, S.; Sefkow, F.; Shushkevich, S.; South, D.; Steder, M.; Wuensch, E.; Begzsuren, K.; Ravdandorj, T.; Tseepeldorj, B.; Bizot, J.C.; Brisson, V.; Delcourt, B.; Jacquet, M.; Pascaud, C.; Tran, T.H.; Zhang, Z.; Zomer, F.; Boudry, V.; Moreau, F.; Specka, A.; Bozovic-Jelisavcic, I.; Pandurovic, M.; Bracinik, J.; Kenyon, I.R.; Newman, P.R.; Thompson, P.D.; Bruncko, D.; Cerny, V.; Ferencei, J.; Bunyatyan, A.; Bylinkin, A.; Bystritskaya, L.; Fedotov, A.; Lubimov, V.; Ozerov, D.; Rostovtsev, A.; Zhokin, A.; Cantun Avila, K.B.; Contreras, J.G.; Ruiz Tabasco, J.E.; Ceccopieri, F.; Delvax, J.; Wolf, E.A. de; Favart, L.; Hreus, T.; Janssen, X.; Roosen, R.; Staykova, Z.; Mechelen, P. van; Cerny, K.; Pokorny, B.; Polifka, R.; Salek, D.; Valkarova, A.; Zacek, J.; Zlebcik, R.; Chekelian, V.; Dossanov, A.; Grindhammer, G.; Kiesling, C.; Coughlan, J.A.; Morris, J.V.; Sankey, D.P.C.; Cvach, J.; Hladky, J.; Reimer, P.; Zalesak, J.; Dainton, J.B.; Gabathuler, E.; Greenshaw, T.; Klein, M.; Kluge, T.; Kretzschmar, J.; Laycock, P.; Maxfield, S.J.; Mehta, A.; Patel, G.D.; Daum, K.; Meyer, H.; Diaconu, C.; Hoffmann, D.; Sauvan, E.; Vallee, C.; Dobre, M.; Kogler, R.; Dodonov, V.; Povh, B.; Egli, S.; Hildebrandt, M.; Horisberger, R.; Feltesse, J.; Perez, E.; Schoeffel, L.; Goerlich, L.; Mikocki, S.; Milcewicz-Mika, I.; Nowak, G.; Sopicki, P.; Turnau, J.; Grab, C.; Henderson, R.C.W.; Sloan, T.; Hennekemper, E.; Herbst, M.; Krueger, K.; Lendermann, V.; Schultz-Coulon, H.C.; Henschel, H.; Hiller, K.H.; Kostka, P.; Lange, W.; Naumann, T.; Herrera, G.; Lopez-Fernandez, R.; Huber, F.; Pirumov, H.; Sauter, M.; Schoening, A.; Joensson, L.; Jung, H.; Kapichine, M.; Morozov, A.; Nikitin, D.; Palichik, V.; Spaskov, V.; Landon, M.P.J.; Rizvi, E.; Traynor, D.; Martyn, H.U.; Mueller, K.; Robmann, P.; Straumann, U.; Truoel, P.; Stella, B.; Sykora, T.; Tsakov, I.; Wegener, D.; Collaboration: H1 Collaboration

2012-07-15

The diffractive process ep{yields}eXY, where Y denotes a proton or its low mass excitation with M{sub Y}<1.6 GeV, is studied with the H1 experiment at HERA. The analysis is restricted to the phase space region of the photon virtuality 3{<=}Q{sup 2}{<=} 1600 GeV {sup 2}, the square of the four-momentum transfer at the proton vertex vertical stroke t vertical stroke < 1.0 GeV {sup 2} and the longitudinal momentum fraction of the incident proton carried by the colourless exchange x{sub P}<0.05. Triple differential cross sections are measured as a function of x{sub P}, Q {sup 2} and {beta}=x/x{sub P} where x is the Bjorken scaling variable. These measurements are made after selecting diffractive events by demanding a large empty rapidity interval separating the final state hadronic systems X and Y. High statistics measurements covering the data taking periods 1999-2000 and 2004-2007 are combined with previously published results in order to provide a single set of diffractive cross sections from the H1 experiment using the large rapidity gap selection method. The combined data represent a factor between three and thirty increase in statistics with respect to the previously published results. The measurements are compared with predictions from NLO QCD calculations based on diffractive parton densities and from a dipole model. The proton vertex factorisation hypothesis is tested. (orig.)

Reconstruction of Stress and Composition Profiles from X-ray Diffraction Experiments - How to Avoid Ghost Stresses?

DEFF Research Database (Denmark)

Christiansen, Thomas; Somers, Marcel A.J.

2004-01-01

On evaluating lattice strain-depth or stress-depth profiles with X-ray diffraction, the variation of the information depth while combining various tilt angles,psi, in combination with lattice spacing gradients leads to artefacts,so-called ghost or fictitious stresses. X-ray diffraction lattice...... method for the evaluation of stress/strain and composition profiles, while minimising the risk for ghost stresses....

Characterization of Polycrystalline Materials Using Synchrotron X-ray Imaging and Diffraction Techniques

DEFF Research Database (Denmark)

Ludwig, Wolfgang; King, A.; Herbig, M.

2010-01-01

The combination of synchrotron radiation x-ray imaging and diffraction techniques offers new possibilities for in-situ observation of deformation and damage mechanisms in the bulk of polycrystalline materials. Minute changes in electron density (i.e., cracks, porosities) can be detected using...... propagation based phase contrast imaging, a 3-D imaging mode exploiting the coherence properties of third generation synchrotron beams. Furthermore, for some classes of polycrystalline materials, one may use a 3-D variant of x-ray diffraction imaging, termed x-ray diffraction contrast tomography. X-ray...

Time-of-flight studies of multiple Bragg reflections in cylindrically bent perfect crystals

Czech Academy of Sciences Publication Activity Database

Mikula, Pavol; Furusaka, M.; Ohkubob, K.; Šaroun, Jan

2012-01-01

Roč. 45, č. 12 (2012), s. 1248-1253 ISSN 0021-8898 R&D Projects: GA AV ČR KJB100480901; GA ČR GAP204/10/0654 Institutional support: RVO:61389005 Keywords : neutron diffraction * time-of-flight method * multiple reflections * bent perfect crystals Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 3.343, year: 2012

Bisphosphonate ISS Flight Experiment

Science.gov (United States)

LeBlanc, Adrian; Matsumoto, Toshio; Jones, Jeffrey; Shapiro, Jay; Lang, Thomas; Shackleford, Linda; Smith, Scott M.; Evans, Harlan; Spector, Elizabeth; Ploutz-Snyder, Robert;

X-ray diffraction measurements in KCl shocked along [100

International Nuclear Information System (INIS)

D'Almeida, T.; Gupta, Y.M.

2000-01-01

Real time x-ray diffraction measurements were used to examine the polymorphic phase transformation in KCl shocked along the [100] direction. Shock wave continuum data, obtained previously by Hayes, were used to design the experiments and to predict diffraction from KCl shocked to different peak stresses. Here, we present the results obtained below the transition stress: between 1.4 and 2 GPa. Diffraction data obtained were quantitatively related to macroscopic compression. Interplanar spacing measurements revealed isotropic compression of the unit cell in contrast to previously reported results. Above the transition stress, descriptions of the atomic arrangement with respect to shock propagation (not available in the literature) are required for setting up the detection system. Hence, continuum results in combination with various crystallographic considerations were utilized to obtain data above the transition stress

Image degradation characteristics and restoration based on regularization for diffractive imaging

Science.gov (United States)

Zhi, Xiyang; Jiang, Shikai; Zhang, Wei; Wang, Dawei; Li, Yun

2017-11-01

The diffractive membrane optical imaging system is an important development trend of ultra large aperture and lightweight space camera. However, related investigations on physics-based diffractive imaging degradation characteristics and corresponding image restoration methods are less studied. In this paper, the model of image quality degradation for the diffraction imaging system is first deduced mathematically based on diffraction theory and then the degradation characteristics are analyzed. On this basis, a novel regularization model of image restoration that contains multiple prior constraints is established. After that, the solving approach of the equation with the multi-norm coexistence and multi-regularization parameters (prior's parameters) is presented. Subsequently, the space-variant PSF image restoration method for large aperture diffractive imaging system is proposed combined with block idea of isoplanatic region. Experimentally, the proposed algorithm demonstrates its capacity to achieve multi-objective improvement including MTF enhancing, dispersion correcting, noise and artifact suppressing as well as image's detail preserving, and produce satisfactory visual quality. This can provide scientific basis for applications and possesses potential application prospects on future space applications of diffractive membrane imaging technology.

Measurement and QCD analysis of diffractive jet cross sections in deep inelastic scattering at HERA

Energy Technology Data Exchange (ETDEWEB)

Mozer, M.U.

2006-07-24

Differential cross sections for the production of two jets in diffractive deep inelastic scattering (DIS) at HERA are presented. The process studied is of the type ep{yields}eXY, where the central hadronic system X contains at least two jets and is separated from the system Y by a gap in rapidity. The forward system Y consists of an elastically scattered proton or a low mass dissociation system. The data were taken with the H1 detector during the years of 1999 and 2000 and correspond to an integrated luminosity of 51.5 pb{sup -1}. The measured cross sections are compared to fixed order NLO QCD predictions, that use diffractive parton densities which have previously been determined by a NLO QCD analysis of inclusive diffractive DIS at H1. The prediction and the data show significant differences. However, the dijet cross section is dominated by the diffractive gluon density, which can be extracted by the above mentioned analysis only with considerable uncertainty. Hence a combined QCD analysis of the previously published inclusive diffractive data and the dijet data is performed. This combined fit analysis allows the determination of diffractive quark and gluon densities with comparable precision. The common description of inclusive diffractive data and the dijet data confirms QCD factorization. (orig.)

Inclusive diffractive cross sections in deep inelastic ep scattering at HERA

International Nuclear Information System (INIS)

Sola, Valentina

2012-04-01

Diffractive deep-inelastic scattering events in ep collisions at HERA are the subject of this thesis. The cross sections for inclusive diffraction, ep → eXp, measured by the H1 and ZEUS Collaborations were combined, providing a model-independent check of the data consistency and a cross calibration between the two experiments, and resulting in single data sets with improved accuracy and precision. Two sets of combined results were obtained. The cross sections measured using the proton-spectrometer data were combined, both in the range of t, the squared four-momentum transfer at the proton vertex, common to the two experiments (0.09 2 ) and in the extended t-range vertical stroke t vertical stroke 2 . The resulting cross sections cover the region 2.5≤ Q 2 ≤200 GeV 2 in photon virtualities, 0.0003≤x P ≤0.09 in the proton fractional momentum losses and 0.0018≤ β ≤0.816 in β=x/x P , where x is the Bjorken scaling variable. The cross sections obtained from data with the large rapidity gap signature were also combined in the kinematic range 2.5≤ Q 2 ≤1600 GeV 2 , 0.0003≤x P ≤0.03 and 0.0017≤ β ≤0.8, for masses of the hadronic final state M X >4 GeV. The inclusive diffractive reduced cross section σ r D(3) was measured with data collected by the ZEUS detector, at two different centre-of-mass energies, 318 and 225 GeV. The diffractive data were selected with the large rapidity gap method in the kinematic region 20 2 2 , 0.05 P or similar 0.55), the inelasticity of the interaction.

Diffractive interactions

International Nuclear Information System (INIS)

Del Duca, V.; Marage, P.

1996-08-01

The general framework of diffractive deep inelastic scattering is introduced and reports given in the session on diffractive interactions at the international workshop on deep-inelastic scattering and related phenomena, Rome, April 1996, are presented. (orig.)

Development of splitting convergent beam electron diffraction (SCBED)

Energy Technology Data Exchange (ETDEWEB)

Houdellier, Florent, E-mail: Florent.Houdellier@cemes.fr [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse (France); Röder, Falk [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse (France); Triebenberg Lab, Institut für Strukturphysik, Technische Universität Dresden, D-01062 Dresden (Germany); Snoeck, Etienne [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse (France)

2015-12-15

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. - Highlights: • Using a condenser biprism, we split the CBED pattern in two half-CBED disks. • We have determined the electron optical conditions used to perform various SCBED. • We propose new applications possible for this new SCBED configuration.

A synchrotron X-ray diffraction study of non-proportional strain-path effects

International Nuclear Information System (INIS)

Collins, D.M.; Erinosho, T.; Dunne, F.P.E.; Todd, R.I.; Connolley, T.; Mostafavi, M.; Kupfer, H.; Wilkinson, A.J.

2017-01-01

Common alloys used in sheet form can display a significant ductility benefit when they are subjected to certain multiaxial strain paths. This effect has been studied here for a polycrystalline ferritic steel using a combination of Nakajima bulge testing, X-ray diffraction during biaxial testing of cruciform samples and crystal plasticity finite element (CPFE) modelling. Greatest gains in strain to failure were found when subjecting sheets to uniaxial loading followed by balanced biaxial deformation, resulting in a total deformation close to plane-strain. A combined strain of approximately double that of proportional loading was achieved. The evolution of macrostrain, microstrain and texture during non-proportional loading were evaluated by in-situ high energy synchrotron diffraction. The results have demonstrated that the inhomogeneous strain accumulation from non-proportional deformation is strongly dependent on texture and the applied strain-ratio of the first deformation pass. Experimental diffraction evidence is supported by results produced by a novel method of CPFE-derived diffraction simulation. Using constitutive laws selected on the basis of good agreement with measured lattice strain development, the CPFE model demonstrated the capability to replicate ductility gains measured experimentally.

Diffraction coherence in optics

CERN Document Server

Françon, M; Green, L L

2013-01-01

Diffraction: Coherence in Optics presents a detailed account of the course on Fraunhofer diffraction phenomena, studied at the Faculty of Science in Paris. The publication first elaborates on Huygens' principle and diffraction phenomena for a monochromatic point source and diffraction by an aperture of simple form. Discussions focus on diffraction at infinity and at a finite distance, simplified expressions for the field, calculation of the path difference, diffraction by a rectangular aperture, narrow slit, and circular aperture, and distribution of luminous flux in the airy spot. The book th

Influence of seismic diffraction for high-resolution imaging: applications in offshore Malaysia

Science.gov (United States)

Bashir, Yasir; Ghosh, Deva Prasad; Sum, Chow Weng

2018-04-01

Small-scale geological discontinuities are not easy to detect and image in seismic data, as these features represent themselves as diffracted rather than reflected waves. However, the combined reflected and diffracted image contains full wave information and is of great value to an interpreter, for instance enabling the identification of faults, fractures, and surfaces in built-up carbonate. Although diffraction imaging has a resolution below the typical seismic wavelength, if the wavelength is much smaller than the width of the discontinuity then interference effects can be ignored, as they would not play a role in generating the seismic diffractions. In this paper, by means of synthetic examples and real data, the potential of diffraction separation for high-resolution seismic imaging is revealed and choosing the best method for preserving diffraction are discussed. We illustrate the accuracy of separating diffractions using the plane-wave destruction (PWD) and dip frequency filtering (DFF) techniques on data from the Sarawak Basin, a carbonate field. PWD is able to preserve the diffraction more intelligently than DFF, which is proven in the results by the model and real data. The final results illustrate the effectiveness of diffraction separation and possible imaging for high-resolution seismic data of small but significant geological features.

Combined effect of space flight and radiation on skeletal muscles of rats

International Nuclear Information System (INIS)

Ilyina-Kakueva, E.I.; Portugalov, V.V.

1977-01-01

Skeletal muscles of rats flown for 20.5 d aboard the biosatellite Cosmos-690 and irradiated with a dose of 800 rads on the 10th flight day were studied. The radiation exposure aggravated the severity of atrophic and dystrophic processes in m. soleus and atrophic process in m. gastrocnemius that developed under the conditions of weightlessness and hypokinesia. At the same time, an exposure to penetrating radiation did not affect the muscles where no flight-induced pathologies occurred. The radiation affected the pattern of reparation in those regions of the soleus muscle that developed pathology inflight, slowed down resorption of the connective tissue formed during the pathological process, and inhibited the course of the reparative process

Nanox: a miniature mechanical stress rig designed for near-field X-ray diffraction imaging techniques.

Science.gov (United States)

Gueninchault, N; Proudhon, H; Ludwig, W

2016-11-01

Multi-modal characterization of polycrystalline materials by combined use of three-dimensional (3D) X-ray diffraction and imaging techniques may be considered as the 3D equivalent of surface studies in the electron microscope combining diffraction and other imaging modalities. Since acquisition times at synchrotron sources are nowadays compatible with four-dimensional (time lapse) studies, suitable mechanical testing devices are needed which enable switching between these different imaging modalities over the course of a mechanical test. Here a specifically designed tensile device, fulfilling severe space constraints and permitting to switch between X-ray (holo)tomography, diffraction contrast tomography and topotomography, is presented. As a proof of concept the 3D characterization of an Al-Li alloy multicrystal by means of diffraction contrast tomography is presented, followed by repeated topotomography characterization of one selected grain at increasing levels of deformation. Signatures of slip bands and sudden lattice rotations inside the grain have been shown by means of in situ topography carried out during the load ramps, and diffraction spot peak broadening has been monitored throughout the experiment.

Water-wave diffraction and radiation by multiple three-dimensional bodies over a mild-slope bottom

DEFF Research Database (Denmark)

Ruiz, Pau Mercadé; Ferri, Francesco; Kofoed, Jens Peter

2017-01-01

Highlights •A tool to model wave diffraction and radiation in mild-slope bottoms is proposed. •The tool combines a mild-slope equation model with diffraction transfer matrices. •The tool predictions are verified against analytical solutions for two test problems....

Diffraction limited focusing with controllable arbitrary three-dimensional polarization

International Nuclear Information System (INIS)

Chen, Weibin; Zhan, Qiwen

2010-01-01

We propose a new approach that enables full control over the three-dimensional state of polarization and the field distribution near the focus of a high numerical aperture objective lens. By combining the electric dipole radiation and a vectorial diffraction method, the input field at the pupil plane for generating arbitrary three-dimensionally oriented linear polarization at the focal point with a diffraction limited spot size is found analytically by solving the inverse problem. Arbitrary three-dimensional elliptical polarization can be obtained by introducing a second electric dipole oriented in the orthogonal plane with appropriate amplitude and phase differences

First observation of new effects at the set-up for searching for a neutron electric dipole moment by a crystal-diffraction method

CERN Document Server

Fedorov, V V; Semenikhin, S Y; Voronin, V V

2002-01-01

First observation of new effects was carried out using the set-up created for searching for a neutron electric dipole moment (EDM) by a crystal-diffraction method. For the first time the neutron dynamical Laue diffraction for the Bragg angles close to a right angle (up to 87 ) was studied, using the direct diffraction beam and a thick (propor to 3.5-cm) crystal. The effect of an essential time delay of diffracting neutrons inside the crystal for Bragg angles close to 90 was experimentally observed, using a time-of-flight method. The phenomenon of neutron-beam depolarization was first experimentally observed for the case of Laue diffraction in a noncentrosymmetric alpha-quartz crystal. It is experimentally proved that the interplanar electric field, affecting a neutron in a crystal, maintains its value up to Bragg angles equal to 87 . These results confirm the opportunity to increase by more than an order of magnitude the sensitivity of the method to the neutron EDM, using the diffraction angles close to 90 , ...

Holographic analysis of diffraction structure factors

International Nuclear Information System (INIS)

Marchesini, S.; Bucher, J.J.; Shuh, D.K.; Fabris, L.; Press, M.J.; West, M.W.; Hussain, Z.; Mannella, N.; Fadley, C.S.; Van Hove, M.A.; Stolte, W.C.

2002-01-01

We combine the theory of inside-source/inside-detector x-ray fluorescence holography and Kossel lines/ x ray standing waves in kinematic approximation to directly obtain the phases of the diffraction structure factors. The influence of Kossel lines and standing waves on holography is also discussed. We obtain partial phase determination from experimental data obtaining the sign of the real part of the structure factor for several reciprocal lattice vectors of a vanadium crystal

Combined Raman/LIBS spectrometer elegant breadboard: built and tested - and flight model spectrometer unit

Science.gov (United States)

Ahlers, B.; Hutchinson, I.; Ingley, R.

2017-11-01

A spectrometer for combined Raman and Laser Induced Breakdown Spectroscopy (LIBS) is amongst the different instruments that have been pre-selected for the Pasteur payload of the ExoMars rover. It is regarded as a fundamental, next-generation instrument for organic, mineralogical and elemental characterisation of Martian soil, rock samples and organic molecules. Raman spectroscopy and LIBS will be integrated into a single instrument sharing many hardware commonalities [1]. The combined Raman / LIBS instrument has been recommended as the highest priority mineralogy instrument to be included in the rover's analytical laboratory for the following tasks: Analyse surface and sub-surface soil and rocks on Mars, identify organics in the search for life and determine soil origin & toxicity. The synergy of the system is evident: the Raman spectrometer is dedicated to molecular analysis of organics and minerals; the LIBS provides information on the sample's elemental composition. An international team, under ESA contract and with the leadership of TNO Science and Industry, has built and tested an Elegant Bread Board (EBB) of the combined Raman / LIBS instrument. The EBB comprises a specifically designed, extremely compact, spectrometer with high resolution over a large wavelength range, suitable for both Raman spectroscopy and LIBS measurements. The EBB also includes lasers, illumination and imaging optics as well as fibre optics for light transfer. A summary of the functional and environmental requirements together with a description of the optical design and its expected performance are described in [2]. The EBB was developed and constructed to verify the instruments' end-to-end functional performance with natural samples. The combined Raman / LIBS EBB realisation and test results of natural samples will be presented. For the Flight Model (FM) instrument, currently in the design phase, the Netherlands will be responsible for the design, development and verification of the

Multi-UAV Flight using Virtual Structure Combined with Behavioral Approach

Directory of Open Access Journals (Sweden)

Kownacki Cezary

2016-06-01

Full Text Available Implementations of multi-UAV systems can be divided mainly into two different approaches, centralised system that synchronises positions of each vehicle by a ground station and an autonomous system based on decentralised control, which offers more flexibility and independence. Decentralisation of multi-UAV control entails the need for information sharing between all vehicles, what in some cases could be problematic due to a significant amount of data to be sent over the wireless network. To improve the reliability and the throughput of information sharing inside the formation of UAVs, this paper proposes an approach that combines virtual structure with a leader and two flocking behaviours. Each UAV has assigned different virtual migration point referenced to the leader's position which is simultaneously the origin of a formation reference frame. All migration points create together a virtual rigid structure. Each vehicle uses local behaviours of cohesion and repulsion respectively, to track its own assigned point in the structure and to avoid a collision with the previous UAV in the structure. To calculate parameters of local behaviours, each UAV should know position and attitude of the leader to define the formation reference frame and also the actual position of the previous UAV in the structure. Hence, information sharing can be based on a chain of local peer-to-peer communication between two consecutive vehicles in the structure. In such solution, the information about the leader could be sequentially transmitted from one UAV to another. Numerical simulations were prepared and carried out to verify the effectiveness of the presented approach. Trajectories recorded during those simulations show collective, coherence and collision-free flights of the formation created with five UAVs.

Combined experimental powder X-ray diffraction and DFT data to obtain the lowest energy molecular conformation of friedelin

International Nuclear Information System (INIS)

Oliveira, Djalma Menezes de; Mussel, Wagner da Nova; Duarte, Lucienir Pains; Silva, Gracia Divina de Fatima; Duarte, Helio Anderson; Gomes, Elionai Cassiana de Lima; Guimaraes, Luciana; Vieira Filho, Sidney A.

2012-01-01

Friedelin molecular conformers were obtained by Density Functional Theory (DFT) and by ab initio structure determination from powder X-ray diffraction. Their conformers with the five rings in chair-chair-chair-boat-boat, and with all rings in chair, are energy degenerated in gas-phase according to DFT results. The powder diffraction data reveals that rings A, B and C of friedelin are in chair, and rings D and E in boat-boat, conformation. The high correlation values among powder diffraction data, DFT and reported single crystal data indicate that the use of conventional X-ray diffractometer can be applied in routine laboratory analysis in the absence of a single-crystal diffractometer. (author)

Combined experimental powder X-ray diffraction and DFT data to obtain the lowest energy molecular conformation of friedelin

Energy Technology Data Exchange (ETDEWEB)

Oliveira, Djalma Menezes de; Mussel, Wagner da Nova; Duarte, Lucienir Pains; Silva, Gracia Divina de Fatima; Duarte, Helio Anderson; Gomes, Elionai Cassiana de Lima [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Dept. de Quimica; Guimaraes, Luciana [Universidade Federal de Sao Joao Del-Rei (UFSJ), MG (Brazil). Dept. de Ciencias Naturais; Vieira Filho, Sidney A., E-mail: bibo@ef.ufop.br [Universidade Federal de Ouro Preto (UFOP), MG (Brazil). Dept. de Farmacia

2012-07-01

Friedelin molecular conformers were obtained by Density Functional Theory (DFT) and by ab initio structure determination from powder X-ray diffraction. Their conformers with the five rings in chair-chair-chair-boat-boat, and with all rings in chair, are energy degenerated in gas-phase according to DFT results. The powder diffraction data reveals that rings A, B and C of friedelin are in chair, and rings D and E in boat-boat, conformation. The high correlation values among powder diffraction data, DFT and reported single crystal data indicate that the use of conventional X-ray diffractometer can be applied in routine laboratory analysis in the absence of a single-crystal diffractometer. (author)

Effectiveness of cognitive behavioral therapy integrated with systematic desensitization, cognitive behavioral therapy combined with eye movement desensitization and reprocessing therapy, and cognitive behavioral therapy combined with virtual reality exposure therapy methods in the treatment of flight anxiety: a randomized trial.

Science.gov (United States)

Triscari, Maria Teresa; Faraci, Palmira; Catalisano, Dario; D'Angelo, Valerio; Urso, Viviana

2015-01-01

The purpose of the research was to compare the effectiveness of the following treatment methods for fear of flying: cognitive behavioral therapy (CBT) integrated with systematic desensitization, CBT combined with eye movement desensitization and reprocessing therapy, and CBT combined with virtual reality exposure therapy. Overall, our findings have proven the efficacy of all interventions in reducing fear of flying in a pre- to post-treatment comparison. All groups showed a decrease in flight anxiety, suggesting the efficiency of all three treatments in reducing self-report measures of fear of flying. In particular, our results indicated significant improvements for the treated patients using all the treatment programs, as shown not only by test scores but also by participation in the post-treatment flight. Nevertheless, outcome measures maintained a significant effect at a 1-year follow-up. In conclusion, combining CBT with both the application of eye movement desensitization and reprocessing treatment and the virtual stimuli used to expose patients with aerophobia seemed as efficient as traditional cognitive behavioral treatments integrated with systematic desensitization.

Powder diffraction from a continuous microjet of submicrometer protein crystals.

Science.gov (United States)

Shapiro, D A; Chapman, H N; Deponte, D; Doak, R B; Fromme, P; Hembree, G; Hunter, M; Marchesini, S; Schmidt, K; Spence, J; Starodub, D; Weierstall, U

2008-11-01

Atomic-resolution structures from small proteins have recently been determined from high-quality powder diffraction patterns using a combination of stereochemical restraints and Rietveld refinement [Von Dreele (2007), J. Appl. Cryst. 40, 133-143; Margiolaki et al. (2007), J. Am. Chem. Soc. 129, 11865-11871]. While powder diffraction data have been obtained from batch samples of small crystal-suspensions, which are exposed to X-rays for long periods of time and undergo significant radiation damage, the proof-of-concept that protein powder diffraction data from nanocrystals of a membrane protein can be obtained using a continuous microjet is shown. This flow-focusing aerojet has been developed to deliver a solution of hydrated protein nanocrystals to an X-ray beam for diffraction analysis. This method requires neither the crushing of larger polycrystalline samples nor any techniques to avoid radiation damage such as cryocooling. Apparatus to record protein powder diffraction in this manner has been commissioned, and in this paper the first powder diffraction patterns from a membrane protein, photosystem I, with crystallite sizes of less than 500 nm are presented. These preliminary patterns show the lowest-order reflections, which agree quantitatively with theoretical calculations of the powder profile. The results also serve to test our aerojet injector system, with future application to femtosecond diffraction in free-electron X-ray laser schemes, and for serial crystallography using a single-file beam of aligned hydrated molecules.

Neutron xyz - polarization analysis at a time-of-flight instrument

Energy Technology Data Exchange (ETDEWEB)

Ehlers, Georg [ORNL; Stewart, John Ross [ISIS Facility, Rutherford Appleton Laboratory; Andersen, Ken [ESS

2015-01-01

When implementing a dedicated polarization analysis setup at a neutron time-of-flight instrument with a large area detector, one faces enormous challenges. Nevertheless, significant progress has been made towards this goal over the last few years. This paper addresses systematic limitations of the traditional method that is used to make these measurements, and a possible strategy to overcome these limitations. This will be important, for diffraction as well as inelastic experiments, where the scattering occurs mostly out-of-plane.

Radial composition of single InGaN nanowires: a combined study by EDX, Raman spectroscopy, and X-ray diffraction

International Nuclear Information System (INIS)

Gomez-Gomez, M.; Garro, N.; Cantarero, A.; Segura-Ruiz, J.; Martinez-Criado, G.; Chu, M.H.; Denker, C.; Malindretos, J.; Rizzi, A.

2013-01-01

The radial alloy distribution of In x Ga 1-x N nanowires grown by plasma-assisted molecular beam epitaxy has been investigated by three different techniques with nanometric spatial resolution and capability to study single nanowires. Energy-dispersive X-ray spectroscopy radial line-scans revealed a gradient in the alloy composition of individual nanowires. Resonant Raman scattering and spatially resolved X-ray diffraction showed the existence of three distinctive regions with different alloy composition. The combination of the three techniques provides robust evidence of the spontaneous formation of a core-shell structure with a thin Ga-richer shell wrapping an In-rich core at the bottom part of the nanowires. This composition-modulated nanostructure offers an attractive way to explore new device concepts in fully epitaxial nanowire-based solar cells. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Determination of electronic and atomic properties of surface, bulk and buried interfaces: Simultaneous combination of hard X-ray photoelectron spectroscopy and X-ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Rubio-Zuazo, J., E-mail: rubio@esrf.fr [SpLine, Spanish CRG BM25 Beamline at the ESRF, ESRF, B.P. 220, F-38043 Grenoble (France); Instituto de Ciencia de Materiales de Madrid, ICMM, CSIC, Cantoblanco, E-28049 Madrid (Spain); Castro, G.R. [SpLine, Spanish CRG BM25 Beamline at the ESRF, ESRF, B.P. 220, F-38043 Grenoble (France); Instituto de Ciencia de Materiales de Madrid, ICMM, CSIC, Cantoblanco, E-28049 Madrid (Spain)

2013-10-15

Highlights: •We have developed a novel and exceptional tool for non-destructive characterization of bulk and buried interfaces that combine XRD and HAXPES. •We studied the correlation between the atomic, electronic and transport properties of oxygen deficient manganite thin films. •The diffraction data showed a cooperative tilt of the MnO{sub 6} block along the out-of-plane direction. •We shown the absence of the conventional basal plane rotation for the oxygen deficient samples. -- Abstract: Hard X-ray photoelectron spectroscopy (HAXPES) is a powerful novel emerging technique for bulk compositional, chemical and electronic properties determination in a non-destructive way. It benefits from the exceptionally large escape depth of high kinetic energy photoelectrons enabling the study of bulk and buried interfaces up to several tens of nanometres depth. Its advantage over conventional XPS is based on the long mean free path of high kinetic energetic photoelectrons. Using the advantage of tuneable X-ray radiation provided by synchrotron sources the photoelectron kinetic energy, i.e. the information depth can be changed and consequently electronic and compositional depth profiles can be obtained. The combination of HAXPES with an atomic structure sensitive technique, as X-ray diffraction, opens a new research field with great potential for many systems in which their electronic properties are intimately linked to their crystallographic structure. At SpLine, the Spanish CRG Beamline at the European Synchrotron Radiation Facility (ESRF) we have developed a novel and exceptional set-up that combine grazing incidence X-ray diffraction (GIXRD) and HAXPES. Both techniques can be operated simultaneously on the same sample and using the same excitation source. The set-up includes a heavy 2S+3D diffractometer and UHV chamber equipped with an electrostatic analyzer. The UHV chamber has also MBE evaporation sources, an ion gun, a LEED optic, a sample heating and cooling

Peculiarities of section topograms for the multiple diffraction of X rays

Energy Technology Data Exchange (ETDEWEB)

Kohn, V. G., E-mail: kohnvict@yandex.ru [National Research Centre “Kurchatov Institute” (Russian Federation); Smirnova, I. A. [Russian Academy of Sciences, Institute of Solid State Physics (Russian Federation)

2016-07-15

The distortion of interference fringes on the section topograms of single crystal due to the multiple diffraction of X rays has been investigated. The cases of the 220 and 400 reflections in a silicon crystal in the form of a plate with a surface oriented normally to the [001] direction are considered both theoretically and experimentally. The same section topogram exhibits five cases of multiple diffraction at small azimuthal angles for the 400 reflection and MoK{sub α} radiation, while the topogram for the 220 reflection demonstrates two cases of multiple diffraction. All these cases correspond to different combinations of reciprocal lattice vectors. Exact theoretical calculations of section topograms for the aforementioned cases of multiple diffraction have been performed for the first time. The section topograms exhibit two different distortion regions. The distortions in the central region of the structure are fairly complex and depend strongly on the azimuthal angle. In the tails of the multiple diffraction region, there is a shift of two-beam interference fringes, which can be observed even with a laboratory X-ray source.

Enhancement of diffraction efficiency of laminar-type diffraction gratings overcoated with diamond-like carbon (DLC) in soft x-ray region

Energy Technology Data Exchange (ETDEWEB)

Koike, Masato, E-mail: koike.masato@jaea.go.jp; Imazono, Takashi [Quantum Beam Science Center, Japan Atomic Energy Agency, 8-1-7 Umemidai, Kizugawa, Kyoto 619-0215 Japan (Japan); Nagano, Tetsuya; Sasai, Hiroyuki; Oue, Yuki; Yonezawa, Zeno; Kuramoto, Satoshi [Device Dept., Shimadzu Corp., 1Nishinokyo-Kuwabara-cho, Nakagyo-ku, Kyoto 604-8511 Japan (Japan); Terauchi, Masami [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 Japan (Japan); Takahashi, Hideyuki [Science Equipment Sales Dept., JEOL Ltd., 2-1-1 Ohtemachi, Chiyoda-ku, Tokyo 100-0004 Japan (Japan); Notoya, Satoshi; Murano, Takanori [SA Business Unit, JEOL Ltd., 3-1-2 Musashino, Akishima, Tokyo 196-8558 Japan (Japan)

2016-07-27

Boron is the critical trace element in the production of high quality steel, creating a great demand for an efficient detection method of the B-K emission band at around 6.76 nm. To meet this demand we made a simulation study and obtained a practical method to improve the diffraction efficiency of metal-coated laminar-type gratings for a grazing incidence flat-field spectrograph by overcoating a sufficiently transparent high-density material. In the simulation the diffraction efficiency in a spectral region of 3.5-8.5 nm was computed for several combinations of overcoating materials and coating metals, with various thicknesses of the overcoating layer. The result obtained are: (1) the best overcoating material is high-density diamond-like carbon (DLC) having a density of 3.1 g/cm{sup 3}, (2) its optimum thickness is 24 nm at an angle of incidence of 87.0°, and (3) with this thickness the first-order diffraction efficiency is expected to reach 29.7 %, which well exceeds 15.6 % for Ni-coated (or 14.1 % for Au-coated) grating.

The diffractive achromat full spectrum computational imaging with diffractive optics

KAUST Repository

Peng, Yifan

2016-07-11

Diffractive optical elements (DOEs) have recently drawn great attention in computational imaging because they can drastically reduce the size and weight of imaging devices compared to their refractive counterparts. However, the inherent strong dispersion is a tremendous obstacle that limits the use of DOEs in full spectrum imaging, causing unacceptable loss of color fidelity in the images. In particular, metamerism introduces a data dependency in the image blur, which has been neglected in computational imaging methods so far. We introduce both a diffractive achromat based on computational optimization, as well as a corresponding algorithm for correction of residual aberrations. Using this approach, we demonstrate high fidelity color diffractive-only imaging over the full visible spectrum. In the optical design, the height profile of a diffractive lens is optimized to balance the focusing contributions of different wavelengths for a specific focal length. The spectral point spread functions (PSFs) become nearly identical to each other, creating approximately spectrally invariant blur kernels. This property guarantees good color preservation in the captured image and facilitates the correction of residual aberrations in our fast two-step deconvolution without additional color priors. We demonstrate our design of diffractive achromat on a 0.5mm ultrathin substrate by photolithography techniques. Experimental results show that our achromatic diffractive lens produces high color fidelity and better image quality in the full visible spectrum. © 2016 ACM.

3-D growth of a short fatigue crack within a polycrystalline microstructure studied using combined diffraction and phase-contrast X-ray tomography

Energy Technology Data Exchange (ETDEWEB)

Herbig, Michael [Universite de Lyon, Lyon, MATEIS, UMR5510 CNRS, 69621 Villeurbanne (France); King, Andrew [GKSS-Research Centre, Geesthacht (Germany); Reischig, Peter [Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany); Proudhon, Henry [MINES ParisTech, Centre des materiaux, CNRS UMR 7633, BP 87, 91003 Evry Cedex (France); Lauridsen, Erik M. [Riso-DTU, Technical University of Denmark, Roskilde (Denmark); Marrow, James [Manchester Materials Science Centre, Manchester (United Kingdom); Buffiere, Jean-Yves [Universite de Lyon, Lyon, MATEIS, UMR5510 CNRS, 69621 Villeurbanne (France); Ludwig, Wolfgang, E-mail: wolfgang.ludwig@insa-lyon.fr [Universite de Lyon, Lyon, MATEIS, UMR5510 CNRS, 69621 Villeurbanne (France); European Synchrotron Radiation Facility, Grenoble, France, BP 220, 38043 Grenoble (France)

2011-01-15

X-ray diffraction contrast tomography is a recently developed, non-destructive synchrotron imaging technique which characterizes microstructure and grain orientation in polycrystalline materials in three dimensions. By combining it with propagation-based phase-contrast tomography it is possible to get a full picture description for the analysis of local crack growth rate of short fatigue cracks in three dimensions: the three-dimensional crack morphology at different propagation stages, and the shape and orientation of the grains around the crack. An approach has been developed on the metastable beta titanium alloy Ti 21S that allows for visualization and analysis of the growth rate and crystallographic orientation of the fracture surface.

3-D growth of a short fatigue crack within a polycrystalline microstructure studied using combined diffraction and phase-contrast X-ray tomography

International Nuclear Information System (INIS)

Herbig, Michael; King, Andrew; Reischig, Peter; Proudhon, Henry; Lauridsen, Erik M.; Marrow, James; Buffiere, Jean-Yves; Ludwig, Wolfgang

2011-01-01

X-ray diffraction contrast tomography is a recently developed, non-destructive synchrotron imaging technique which characterizes microstructure and grain orientation in polycrystalline materials in three dimensions. By combining it with propagation-based phase-contrast tomography it is possible to get a full picture description for the analysis of local crack growth rate of short fatigue cracks in three dimensions: the three-dimensional crack morphology at different propagation stages, and the shape and orientation of the grains around the crack. An approach has been developed on the metastable beta titanium alloy Ti 21S that allows for visualization and analysis of the growth rate and crystallographic orientation of the fracture surface.

Restoration of diffracted far field at the output of circular diffraction waveplate

International Nuclear Information System (INIS)

Hovhannisyan, D; Margaryan, H; Abrahamyan, V; Hakobyan, N; Tabiryan, N

2014-01-01

The light propagation in an anisotropic periodic media, such us circular diffraction waveplate (CDW) by a finite-difference time-domain (FDTD) technique is studied. The FDTD numerical simulation and the subsequent Fourier transform of the diffracted electric near field was been used for study of ability of CDW to diffract a laser beam and simultaneously convert polarization state. The FDTD simulation results used to restore the diffracted electric far field at the CDW output. an abstract

Boundary diffraction wave integrals for diffraction modeling of external occulters

OpenAIRE

Cady, E.

2012-01-01

An occulter is a large diffracting screen which may be flown in conjunction with a telescope to image extrasolar planets. The edge is shaped to minimize the diffracted light in a region beyond the occulter, and a telescope may be placed in this dark shadow to view an extrasolar system with the starlight removed. Errors in position, orientation, and shape of the occulter will diffract additional light into this region, and a challenge of modeling an occulter system is to accurately and quickly...

Diffraction efficiency enhancement of femtosecond laser-engraved diffraction gratings due to CO2 laser polishing

International Nuclear Information System (INIS)

Choi, Hun-Kook; Jung, Deok; Sohn, Ik-Bu; Noh, Young-Chul; Lee, Yong-Tak; Kim, Jin-Tae; Ahsan, Shamim

2014-01-01

This research demonstrates laser-assisted fabrication of high-efficiency diffraction gratings in fused-silica glass samples. Initially, femtosecond laser pulses are used to engrave diffraction gratings on the glass surfaces. Then, these micro-patterned glass samples undergo CO 2 laser polishing process. unpolished diffraction gratings encoded in the glass samples show an overall diffraction efficiency of 18.1%. diffraction gratings imprinted on the glass samples and then polished four times by using a CO 2 laser beam attain a diffraction efficiency of 32.7%. We also investigate the diffraction patterns of the diffraction gratings encoded on fused-silica glass surfaces. The proposed CO 2 laser polishing technique shows great potential in patterning high-efficiency diffraction gratings on the surfaces of various transparent materials.

Diffractive optical elements for transformation of modes in lasers

Science.gov (United States)

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.

Inclusive diffractive cross sections in deep inelastic ep scattering at HERA

Energy Technology Data Exchange (ETDEWEB)

Sola, Valentina

2012-04-15

Diffractive deep-inelastic scattering events in ep collisions at HERA are the subject of this thesis. The cross sections for inclusive diffraction, ep {yields} eXp, measured by the H1 and ZEUS Collaborations were combined, providing a model-independent check of the data consistency and a cross calibration between the two experiments, and resulting in single data sets with improved accuracy and precision. Two sets of combined results were obtained. The cross sections measured using the proton-spectrometer data were combined, both in the range of t, the squared four-momentum transfer at the proton vertex, common to the two experiments (0.09< vertical stroke t vertical stroke <0.55 GeV{sup 2}) and in the extended t-range vertical stroke t vertical stroke <1 GeV{sup 2}. The resulting cross sections cover the region 2.5{<=} Q{sup 2} {<=}200 GeV{sup 2} in photon virtualities, 0.0003{<=}x{sub P}{<=}0.09 in the proton fractional momentum losses and 0.0018{<=} {beta} {<=}0.816 in {beta}=x/x{sub P}, where x is the Bjorken scaling variable. The cross sections obtained from data with the large rapidity gap signature were also combined in the kinematic range 2.5{<=} Q{sup 2} {<=}1600 GeV{sup 2}, 0.0003{<=}x{sub P}{<=}0.03 and 0.0017{<=} {beta} {<=}0.8, for masses of the hadronic final state M{sub X}>4 GeV. The inclusive diffractive reduced cross section {sigma}{sub r}{sup D(3)} was measured with data collected by the ZEUS detector, at two different centre-of-mass energies, 318 and 225 GeV. The diffractive data were selected with the large rapidity gap method in the kinematic region 20< Q{sup 2} <130 GeV{sup 2}, 0.05< {beta} <0.85 and 0.00063or similar 0.55), the inelasticity of the interaction.

Phase behavior in diffraction

International Nuclear Information System (INIS)

Checon, A.

1983-01-01

Theoretical formulation of a straight edge diffraction shows a phase difference of π/2 between the incoming and diffracted waves. Experiments using two straight edges do not confirm the π/2 difference but suggest that the incoming wave is in phase with the wave diffracted into the shadowed region of the edge and out of phase by a factor of π with the wave diffracted into the illuminated region. (Author) [pt

Speech Recognition Interfaces Improve Flight Safety

Science.gov (United States)

2013-01-01

"Alpha, Golf, November, Echo, Zulu." "Sierra, Alpha, Golf, Echo, Sierra." "Lima, Hotel, Yankee." It looks like some strange word game, but the combinations of words above actually communicate the first three points of a flight plan from Albany, New York to Florence, South Carolina. Spoken by air traffic controllers and pilots, the aviation industry s standard International Civil Aviation Organization phonetic alphabet uses words to represent letters. The first letter of each word in the series is combined to spell waypoints, or reference points, used in flight navigation. The first waypoint above is AGNEZ (alpha for A, golf for G, etc.). The second is SAGES, and the third is LHY. For pilots of general aviation aircraft, the traditional method of entering the letters of each waypoint into a GPS device is a time-consuming process. For each of the 16 waypoints required for the complete flight plan from Albany to Florence, the pilot uses a knob to scroll through each letter of the alphabet. It takes approximately 5 minutes of the pilot s focused attention to complete this particular plan. Entering such a long flight plan into a GPS can pose a safety hazard because it can take the pilot s attention from other critical tasks like scanning gauges or avoiding other aircraft. For more than five decades, NASA has supported research and development in aviation safety, including through its Vehicle Systems Safety Technology (VSST) program, which works to advance safer and more capable flight decks (cockpits) in aircraft. Randy Bailey, a lead aerospace engineer in the VSST program at Langley Research Center, says the technology in cockpits is directly related to flight safety. For example, "GPS navigation systems are wonderful as far as improving a pilot s ability to navigate, but if you can find ways to reduce the draw of the pilot s attention into the cockpit while using the GPS, it could potentially improve safety," he says.

Diffraction properties study of reflection volume holographic grating in dispersive photorefractive material under ultra-short pulse readout

Energy Technology Data Exchange (ETDEWEB)

Yi Yingyan; Liu Deming; Liu Hairong, E-mail: yiyingyan0410@163.com [Wuhan National Laboratory for Optoelectronics, School of Optoelectronic Science and Engineering, Huazhong University of Science and Technology, Wuhan, 430074 (China)

2011-02-01

Based on the modified Kogelnik diffraction efficiency equation, we study the diffraction intensity spectrum and the total diffraction efficiency of reflection volume holographic gratings in photorefractive media. Taking photorefractive LiNbO{sub 3} crystal as an example, the effect of the grating parameters and the pulse width on the diffraction properties is presented under the influence of crystal material dispersion. Under the combined effects, the diffraction pulse profiles and the total diffraction efficiency are compared with and without crystal material dispersion. The results show that the dispersion will decrease the diffraction intensity. Moreover, when pulse width is smaller or the grating spacing and the grating thickness are larger, the influence of dispersion on diffraction is large. The results of our paper can be used in pulse shaping applications.

A combined neutron and x-ray diffraction study of short- and intermediate-range structural characteristics of Ge-As sulfide glasses

International Nuclear Information System (INIS)

Uzun, S Soyer; Sen, S; Benmore, C J; Aitken, B G

2008-01-01

A combination of neutron and x-ray diffraction has been employed to study the compositional dependence of the atomic structures of Ge x As x S 100-2x glasses with S concentration varying between 33.3 and 70.0 at.%. The nearest-neighbor coordination numbers of Ge and As atoms are always found to be 4 and 3, respectively, irrespective of the glass composition. Ge and As atoms have primarily heteropolar bonding to S atoms in stoichiometric and S-excess glasses with x≤18.2. Low and intermediate levels of deficiency of S (20≤x≤25) are accommodated via the formation of homopolar As-As bonds while Ge atoms remain primarily bonded to four S atoms, resulting in As-rich regions in the glass structure. Ge starts to participate in metal-metal bonding only in the highly S-deficient glasses with 27.5≤x≤33.3. The intermediate-range order and its topological influence on atomic packing in these three compositional regions, in the order of increasing deficiency in S, are controlled by (a) a mixed GeS 2 and As 2 S 3 network, (b) the coexistence of a GeS 2 network and As clusters, and (c) large Ge-As metal-rich regions. This evolution of the intermediate-range structure with composition is consistent with the corresponding variation of the position, intensity and width of the first sharp diffraction peak in the structure factor

Diffraction at TOTEM

OpenAIRE

Antchev, G.; Aspell, P.; Avati, V.; Bagliesi, M.G.; Berardi, V.; Berretti, M.; Bottigli, U.; Bozzo, M.; Brucken, E.; Buzzo, A.; Cafagna, F.; Calicchio, M.; Catanesi, M.G.; Catastini, P.L.; Cecchi, R.

2008-01-01

The TOTEM experiment at the LHC measures the total proton-proton cross section with the luminosity-independent method and the elastic proton-proton cross-section over a wide |t|-range. It also performs a comprehensive study of diffraction, spanning from cross-section measurements of individual diffractive processes to the analysis of their event topologies. Hard diffraction will be studied in collaboration with CMS taking advantage of the large common rapidity coverage for charged and neutral...

New Methodology for Optimal Flight Control using Differential Evolution Algorithms applied on the Cessna Citation X Business Aircraft – Part 2. Validation on Aircraft Research Flight Level D Simulator

OpenAIRE

Yamina BOUGHARI; Georges GHAZI; Ruxandra Mihaela BOTEZ; Florian THEEL

2017-01-01

In this paper the Cessna Citation X clearance criteria were evaluated for a new Flight Controller. The Flight Control Law were optimized and designed for the Cessna Citation X flight envelope by combining the Deferential Evolution algorithm, the Linear Quadratic Regulator method, and the Proportional Integral controller during a previous research presented in part 1. The optimal controllers were used to reach satisfactory aircraft’s dynamic and safe flight operations with respect to the augme...

Systematic investigation of lard polymorphism using combined DSC and time-resolved synchrotron X-ray diffraction

NARCIS (Netherlands)

Kalnin, D.J.E.; Lesieur, P.; Artzner, F.; Keller, G.; Ollivon, M.

2005-01-01

The polymorphic behavior of lard was systematically investigated by differential scanning calorimetry (DSC) while simultaneously monitoring the formation of the different crystal forms with X-ray diffraction (XRDT). To interpret the complex polymorphic evolution of the sample analyzed by regular

Design and evaluation of a Flight Envelope Protection haptic feedback system

NARCIS (Netherlands)

Ellerbroek, J.; Rodriguez Martin, M.J.M.; Lombaerts, T; van Paassen, M.M.; Mulder, M.

2016-01-01

This paper describes the design and evaluation of a shared control, haptic feedback system to communicate Flight Envelope Protection System intent. The concept uses a combination of stiffness feedback and vibration to communicate proximity of the aircraft state to flight envelope boundaries. In

Radial composition of single InGaN nanowires: a combined study by EDX, Raman spectroscopy, and X-ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Gomez-Gomez, M.; Garro, N.; Cantarero, A. [Institut de Ciencia dels Materials, Universitat de Valencia, Paterna (Spain); Segura-Ruiz, J.; Martinez-Criado, G.; Chu, M.H. [European Synchrotron Radiation Facility, Experiments Division, Grenoble (France); Denker, C.; Malindretos, J.; Rizzi, A. [IV. Physikalisches Institut, Georg-August-Universitaet Goettingen (Germany)

2013-10-15

The radial alloy distribution of In{sub x} Ga{sub 1-x}N nanowires grown by plasma-assisted molecular beam epitaxy has been investigated by three different techniques with nanometric spatial resolution and capability to study single nanowires. Energy-dispersive X-ray spectroscopy radial line-scans revealed a gradient in the alloy composition of individual nanowires. Resonant Raman scattering and spatially resolved X-ray diffraction showed the existence of three distinctive regions with different alloy composition. The combination of the three techniques provides robust evidence of the spontaneous formation of a core-shell structure with a thin Ga-richer shell wrapping an In-rich core at the bottom part of the nanowires. This composition-modulated nanostructure offers an attractive way to explore new device concepts in fully epitaxial nanowire-based solar cells. (copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Diffraction at TOTEM

OpenAIRE

Giani, S; Niewiadomski, H; Antchev, G; Aspell, P; Avati, V; Bagliesi, M G; Berardi, V; Berretti, M; Besta, M; Bozzo, M; Brücken, E; Buzzo, A; Cafagna, F; Calicchio, M; Catanesi, M G

2010-01-01

The primary objective of the TOTEM experiment at the LHC is the measurement of the total proton-proton cross section with the luminosity-independent method and the study of elastic proton-proton cross-section over a wide |t|-range. In addition TOTEM also performs a comprehensive study of diffraction, spanning from cross-section measurements of individual diffractive processes to the analysis of their event topologies. Hard diffraction will be studied in collaboration with CMS taking advantage...

Intergrown new zeolite beta polymorphs with interconnected 12-ring channels solved by combining electron crystallography and single-crystal X-ray diffraction

KAUST Repository

Yu, Zhengbao

2012-10-09

Two new polymorphs of zeolite beta, denoted as SU-78A and SU-78B, were synthesized by employing dicyclohexylammonium hydroxides as organic structure-directing agents. The structure was solved by combining transmission electron microscopy and single-crystal X-ray diffraction. SU-78 is an intergrowth of SU-78A and SU-78B and contains interconnected 12-ring channels in three directions. The two polymorphs are built from the same building layer, similar to that for the zeolite beta family. The layer stacking in SU-78, however, is different from those in zeolite beta polymorph A, B, and C, showing new zeolite framework topologies. SU-78 is thermally stable up to 600 °C. © 2012 American Chemical Society.

Time-of-flight neutron Bragg-edge transmission imaging of microstructures in bent steel plates

Energy Technology Data Exchange (ETDEWEB)

Su, Yuhua, E-mail: yuhua.su@j-parc.jp [J-PARC Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Ibaraki 319-1195 (Japan); Oikawa, Kenichi; Harjo, Stefanus; Shinohara, Takenao; Kai, Tetsuya; Harada, Masahide; Hiroi, Kosuke [J-PARC Center, Japan Atomic Energy Agency, 2-4 Shirakata, Tokai, Ibaraki 319-1195 (Japan); Zhang, Shuoyuan; Parker, Joseph Don [Neutron R& D Division, CROSS-Tokai, 162-1 Shirakata, Tokai, Ibaraki 319-1106 (Japan); Sato, Hirotaka [Faculty of Engineering, Hokkaido University, Sapporo 060-8628 (Japan); Shiota, Yoshinori; Kiyanagi, Yoshiaki [Graduate School of Engineering, Nagoya University, Nagoya, Aichi 464-8603 (Japan); Tomota, Yo [Research Center for Strategic Materials, National Institute for Materials Science, Tsukuba 305-0047 (Japan)

2016-10-15

Neutron Bragg-edge transmission imaging makes it possible to quantitatively visualize the two-dimensional distribution of microstructure within a sample. In order to examine its application to engineering products, time-of-flight Bragg-edge transmission imaging experiments using a pulsed neutron source were performed for plastically bent plates composed of a ferritic steel and a duplex stainless steel. The non-homogeneous microstructure distributions, such as texture, crystalline size, phase volume fraction and residual elastic strain, were evaluated for the cross sections of the bent plates. The obtained results were compared with those by neutron diffraction and electron back scatter diffraction, showing that the Bragg-edge transmission imaging is powerful for engineering use.

An optical super-microscope for far-field, real-time imaging beyond the diffraction limit.

Science.gov (United States)

Wong, Alex M H; Eleftheriades, George V

2013-01-01

Optical microscopy suffers from a fundamental resolution limitation arising from the diffractive nature of light. While current solutions to sub-diffraction optical microscopy involve combinations of near-field, non-linear and fine scanning operations, we hereby propose and demonstrate the optical super-microscope (OSM) - a superoscillation-based linear imaging system with far-field working and observation distances - which can image an object in real-time and with sub-diffraction resolution. With our proof-of-principle prototype we report a point spread function with a spot size clearly reduced from the diffraction limit, and demonstrate corresponding improvements in two-point resolution experiments. Harnessing a new understanding of superoscillations, based on antenna array theory, our OSM achieves far-field, sub-diffraction optical imaging of an object without the need for fine scanning, data post-processing or object pre-treatment. Hence the OSM can be used in a wide variety of imaging applications beyond the diffraction limit, including real-time imaging of moving objects.

Microgravity Flight - Accommodating Non-Human Primates

Science.gov (United States)

Dalton, Bonnie P.; Searby, Nancy; Ostrach, Louis

1994-01-01

Spacelab Life Sciences-3 (SLS-3) was scheduled to be the first United States man-tended microgravity flight containing Rhesus monkeys. The goal of this flight as in the five untended Russian COSMOS Bion flights and an earlier American Biosatellite flight, was to understand the biomedical and biological effects of a microgravity environment using the non-human primate as human surrogate. The SLS-3/Rhesus Project and COSMOS Primate-BIOS flights all utilized the rhesus monkey, Macaca mulatta. The ultimate objective of all flights with an animal surrogate has been to evaluate and understand biological mechanisms at both the system and cellular level, thus enabling rational effective countermeasures for future long duration human activity under microgravity conditions and enabling technical application to correction of common human physiological problems within earth's gravity, e.g., muscle strength and reloading, osteoporosis, immune deficiency diseases. Hardware developed for the SLS-3/Rhesus Project was the result of a joint effort with the French Centre National d'Etudes Spatiales (CNES) and the United States National Aeronautics and Space Administration (NASA) extending over the last decade. The flight hardware design and development required implementation of sufficient automation to insure flight crew and animal bio-isolation and maintenance with minimal impact to crew activities. A variety of hardware of varying functional capabilities was developed to support the scientific objectives of the original 22 combined French and American experiments, along with 5 Russian co-investigations, including musculoskeletal, metabolic, and behavioral studies. Unique elements of the Rhesus Research Facility (RRF) included separation of waste for daily delivery of urine and fecal samples for metabolic studies and a psychomotor test system for behavioral studies along with monitored food measurement. As in untended flights, telemetry measurements would allow monitoring of

Initial Flight Test of the Production Support Flight Control Computers at NASA Dryden Flight Research Center

Science.gov (United States)

Carter, John; Stephenson, Mark

1999-01-01

The NASA Dryden Flight Research Center has completed the initial flight test of a modified set of F/A-18 flight control computers that gives the aircraft a research control law capability. The production support flight control computers (PSFCC) provide an increased capability for flight research in the control law, handling qualities, and flight systems areas. The PSFCC feature a research flight control processor that is "piggybacked" onto the baseline F/A-18 flight control system. This research processor allows for pilot selection of research control law operation in flight. To validate flight operation, a replication of a standard F/A-18 control law was programmed into the research processor and flight-tested over a limited envelope. This paper provides a brief description of the system, summarizes the initial flight test of the PSFCC, and describes future experiments for the PSFCC.

Diffraction efficiency enhancement of femtosecond laser-engraved diffraction gratings due to CO{sub 2} laser polishing

Energy Technology Data Exchange (ETDEWEB)

Choi, Hun-Kook [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Chosun University, Gwangju (Korea, Republic of); Jung, Deok; Sohn, Ik-Bu; Noh, Young-Chul; Lee, Yong-Tak [Gwangju Institute of Science and Technology, Gwangju (Korea, Republic of); Kim, Jin-Tae [Chosun University, Gwangju (Korea, Republic of); Ahsan, Shamim [Khulna University, Khulna (Bangladesh)

2014-11-15

This research demonstrates laser-assisted fabrication of high-efficiency diffraction gratings in fused-silica glass samples. Initially, femtosecond laser pulses are used to engrave diffraction gratings on the glass surfaces. Then, these micro-patterned glass samples undergo CO{sub 2} laser polishing process. unpolished diffraction gratings encoded in the glass samples show an overall diffraction efficiency of 18.1%. diffraction gratings imprinted on the glass samples and then polished four times by using a CO{sub 2} laser beam attain a diffraction efficiency of 32.7%. We also investigate the diffraction patterns of the diffraction gratings encoded on fused-silica glass surfaces. The proposed CO{sub 2} laser polishing technique shows great potential in patterning high-efficiency diffraction gratings on the surfaces of various transparent materials.

Diffraction by disordered polycrystalline fibers

International Nuclear Information System (INIS)

Stroud, W.J.; Millane, R.P.

1995-01-01

X-ray diffraction patterns from some polycrystalline fibers show that the constituent microcrystallites are disordered. The relationship between the crystal structure and the diffracted intensities is then quite complicated and depends on the precise kind and degree of disorder present. The effects of disorder on diffracted intensities must be included in structure determinations using diffraction data from such specimens. Theory and algorithms are developed here that allow the full diffraction pattern to be calculated for a disordered polycrystalline fiber made up of helical molecules. The model accommodates various kinds of disorder and includes the effects of finite crystallite size and cylindrical averaging of the diffracted intensities from a fiber. Simulations using these methods show how different kinds, or components, of disorder produce particular diffraction effects. General properties of disordered arrays of helical molecules and their effects on diffraction patterns are described. Implications for structure determination are discussed. (orig.)

Holographic Reconstruction of Photoelectron Diffraction and Its Circular Dichroism for Local Structure Probing

Science.gov (United States)

Matsui, Fumihiko; Matsushita, Tomohiro; Daimon, Hiroshi

2018-06-01

The local atomic structure around a specific element atom can be recorded as a photoelectron diffraction pattern. Forward focusing peaks and diffraction rings around them indicate the directions and distances from the photoelectron emitting atom to the surrounding atoms. The state-of-the-art holography reconstruction algorithm enables us to image the local atomic arrangement around the excited atom in a real space. By using circularly polarized light as an excitation source, the angular momentum transfer from the light to the photoelectron induces parallax shifts in these diffraction patterns. As a result, stereographic images of atomic arrangements are obtained. These diffraction patterns can be used as atomic-site-resolved probes for local electronic structure investigation in combination with spectroscopy techniques. Direct three-dimensional atomic structure visualization and site-specific electronic property analysis methods are reviewed. Furthermore, circular dichroism was also found in valence photoelectron and Auger electron diffraction patterns. The investigation of these new phenomena provides hints for the development of new techniques for local structure probing.

In situ diffraction profile analysis during tensile deformation motivated by molecular dynamics

International Nuclear Information System (INIS)

Van Swygenhoven, H.; Budrovic, Z.; Derlet, P.M.; Froseth, A.G.; Van Petegem, S.

2005-01-01

Molecular dynamics simulations can provide insight into the slip mechanism at the atomic scale and suggest that in nanocrystalline metals dislocations are nucleated and absorbed by the grain boundaries. However, this technique is limited by very short simulation times. Using suggestions from molecular dynamics, we have developed a new in situ X-ray diffraction technique wherein the profile analysis of several Bragg diffraction peaks during tensile deformation is possible. Combining experiment and careful structural analysis the results confirm the suggestions from atomistic simulations

Propulsion systems for vertical flight aircraft

Energy Technology Data Exchange (ETDEWEB)

Brooks, A.

1990-01-01

The present evaluation of VTOL airframe/powerplant integration configurations combining high forward flight speed with safe and efficient vertical flight identifies six configurations that can be matched with one of three powerplant types: turboshafts, convertible-driveshaft lift fans, and gas-drive lift fans. The airframes configurations are (1) tilt-rotor, (2) folded tilt-rotor, (3) tilt-wing, (4) rotor wing/disk wing, (5) lift fan, and (6) variable-diameter rotor. Attention is given to the lift-fan VTOL configuration. The evaluation of these configurations has been conducted by both a joint NASA/DARPA program and the NASA High Speed Rotorcraft program. 7 refs.

Ultrafast coherent diffractive imaging of nanoparticles using X-ray free-electron laser radiation

International Nuclear Information System (INIS)

Kassemeyer, Stephan

2014-01-01

Coherent diffractive imaging with X-ray free-electron lasers (X-FEL) promises high-resolution structure determination of single microscopic particles without the need for crystallization. The diffraction signal of small samples can be very weak, a difficulty that can not be countered by merely increasing the number of photons because the sample would be damaged by a high absorbed radiation dose. Traditional X-ray crystallography avoids this problem by bringing many sample particles into a periodic arrangement, which amplifies the individual signals while distributing the absorbed dose. Depending on the sample, however, crystallization can be very difficult or even impossible. This thesis presents algorithms for a new imaging approach using X-FEL radiation that works with single, non-crystalline sample particles. X-FELs can deliver X-rays with a peak brilliance many orders of magnitude higher than conventional X-ray sources, compensating for their weak interaction cross sections. At the same time, FELs can produce ultra-short pulses down to a few femtoseconds. In this way it is possible to perform ultra-fast imaging, essentially ''freezing'' the atomic positions in time and terminating the imaging process before the sample is destroyed by the absorbed radiation. This thesis primarily focuses on the three-dimensional reconstruction of single (and not necessarily crystalline) particles using coherent diffractive imaging at X-FELs: in order to extract three-dimensional information from scattering data, two-dimensional diffraction patterns from many different viewing angles must be combined. Therefore, the diffraction signal of many identical sample copies in random orientations is measured. The main result of this work is a globally optimal algorithm that can recover the sample orientations solely based on the diffraction signal, enabling three-dimensional imaging for arbitrary samples. The problem of finding three-dimensional orientations is

Diffraction at TOTEM

CERN Document Server

Giani, S; Antchev, G; Aspell, P; Avati, V; Bagliesi, M G; Berardi, V; Berretti, M; Besta, M; Bozzo, M; Brücken, E; Buzzo, A; Cafagna, F; Calicchio, M; Catanesi, M G; Cecchi, R; Ciocci, M A; Dadel, P; Deile, M; Dimovasili, E; Eggert, K; Eremin, V; Ferro, F; Fiergolski, A; García, F; Greco, V; Grzanka, L; Heino, J; Hildén, T; Kaspar, J; Kopal, J; Kundrát, V; Kurvinen, K; Lami, S; Latino, G; Lauhakangas, R; Leszko, R; Lippmaa, E; Lokajícek, M; Lo Vetere, M; Lucas Rodriguez, F; Macrí, M; Magazzù, G; Meucci, M; Minutoli, S; Notarnicola, G; Oliveri, E; Oljemark, F; Orava, R; Oriunno, M; Österberg, K; Pedreschi, E; Petäjäjärvi, J; Prochazka, J; Quinto, M; Radermacher, E; Radicioni, E; Ravotti, F; Rella, G; Robutti, E; Ropelewski, L; Rostkowski, M; Ruggiero, G; Rummel, A; Saarikko, H; Sanguinetti, G; Santroni, A; Scribano, A; Sette, G; Snoeys, W; Spinella, F; Ster, A; Taylor, C; Trummal, A; Turini, N; Whitmore, J; Wu, J; Zalewski, M

2010-01-01

The primary objective of the TOTEM experiment at the LHC is the measurement of the total proton-proton cross section with the luminosity-independent method and the study of elastic proton-proton cross-section over a wide |t|-range. In addition TOTEM also performs a comprehensive study of diffraction, spanning from cross-section measurements of individual diffractive processes to the analysis of their event topologies. Hard diffraction will be studied in collaboration with CMS taking advantage of the large common rapidity coverage for charged and neutral particle detection and the large variety of trigger possibilities even at large luminosities. TOTEM will take data under all LHC beam conditions including standard high luminosity runs to maximise its physics reach. This contribution describes the main features of the TOTEM diffractive physics programme including measurements to be made in the early LHC runs.

Non-diffractive waves

CERN Document Server

Hernandez-Figueroa, Hugo E; Recami, Erasmo

2013-01-01

This continuation and extension of the successful book ""Localized Waves"" by the same editors brings together leading researchers in non-diffractive waves to cover the most important results in their field and as such is the first to present the current state.The well-balanced presentation of theory and experiments guides readers through the background of different types of non-diffractive waves, their generation, propagation, and possible applications. The authors include a historical account of the development of the field, and cover different types of non-diffractive waves, including Airy

A rotorcraft flight/propulsion control integration study

Science.gov (United States)

Ruttledge, D. G. C.

1986-01-01

An eclectic approach was taken to a study of the integration of digital flight and propulsion controls for helicopters. The basis of the evaluation was the current Gen Hel simulation of the UH-60A Black Hawk helicopter with a model of the GE T700 engine. A list of flight maneuver segments to be used in evaluating the effectiveness of such an integrated control system was composed, based on past experience and an extensive survey of the U.S. Army Air-to-Air Combat Test data. A number of possible features of an integrated system were examined and screened. Those that survived the screening were combined into a design that replaced the T700 fuel control and part of the control system in the UH-60A Gen Hel simulation. This design included portions of an existing pragmatic adaptive fuel control designed by the Chandler-Evans Company and an linear quadratic regulator (LQR) based N(p) governor designed by the GE company, combined with changes in the basic Sikorsky Aircraft designed control system. The integrated system exhibited improved total performance in many areas of the flight envelope.

Residual stresses in a composite steel tube measured by neutron diffraction

International Nuclear Information System (INIS)

Taran, Yu.V.; Balagurov, A.M.; Zlokazov, V.B.; Schreiber, J.; Stuhr, U.; Kockelmann, H.

2006-01-01

The triaxial residual stresses in a composite tube from an austenitic stainless steel with a welded ferritic steel cladding were measured by the time-of-flight neutron diffraction method on the POLDI instrument at the PSI SINQ facility. The POLDI results are compared to the results obtained by the destructive turning out method and theoretical predictions of calculations by the finite element method. Only for the tangential component of the stress tensor the semiquantitative agreement of all used methods was observed. There is a clear discrepancy between the results of the different methods in the axial component. For the radial component all methods reveal quite small stresses, however, with some distinct differences in their distributions

A combined diffraction and dielectric properties investigation of Ba3MnNb2O9 complex perovskites

International Nuclear Information System (INIS)

Liu Yun; Withers, Ray L.; Whichello, A.P.; Noren, Lasse; Ting, Valeska; Brink, Frank; Fitz Gerald, John D.

2005-01-01

A combined synthesis, diffraction and dielectric properties investigation of the dependence (and effect) of Mn 2+ /Nb 5+ ordering in Ba 3 MnNb 2 O 9 (BMN) upon annealing atmosphere and processing conditions has been carried out. Annealing in different atmospheres was not found to significantly alter either nominal stoichiometry or structure type. The obtained structure type (disordered metrically cubic or ordered trigonal) as well as the measured electrical properties (in particular, the dielectric loss) were, however, found to be sensitive to the synthesis route. Samples obtained via solid-state reaction were found to be predominantly of 1:2 Mn 2+ /Nb 5+ ordered, P3-bar m1 trigonal structure type whereas samples obtained via an aqueous solution route were found to be of a Mn 2+ /Nb 5+ 'disordered', metrically cubic structure type. All solid-state synthesized samples showed reasonable dielectric properties. The microwave dielectric constant and dielectric quality factor, Q, at 8GHz of an as-synthesized BMN sample were 38 and 100, respectively. By contrast, the dielectric loss of the metrically cubic, Mn 2+ /Nb 5+ 'disordered' samples obtained via an aqueous solution synthesis process were significantly worse

Borehole radar diffraction tomography

Energy Technology Data Exchange (ETDEWEB)

Cho, Seong Jun; Kim, Jung Ho; Yi, Myeong Jong; Chung, Seung Hwan; Lee, Hee Il [Korea Institute of Geology Mining and Materials, Taejon (Korea, Republic of)

1997-12-01

Tomography is widely used as imaging method for determining subsurface structure. Among the reconstruction algorithms for tomographic imaging, travel time tomography is almost applied to imaging subsurface. But isolated small body comparable with the wavelength could not be well recognized by travel time tomography. Other tomographic method are need to improve the imaging process. In the study of this year, diffraction tomography was investigated. The theory for diffraction tomography is based on the 1st-order Born approximation. Multisource holography, which is similar to Kirchihoff migration, is compared with diffraction tomography. To improve 1st-order Born diffraction tomography, two kinds of filter designed from multisource holography and 2-D green function, respectively, applied on the reconstructed image. The algorithm was tested for the numerical modeling data of which algorithm consists of the analytic computation of radar signal in transmitter and receiver regions and 2-D FDM scheme for the propagation of electromagnetic waves in media. The air-filled cavity model to show a typical diffraction pattern was applied to diffraction tomography imaging, and the result shows accurate location and area of cavity. But the calculated object function is not well matched the real object function, because the air-filled cavity model is not satisfied week scattered inhomogeneity for 1st born approximation, and the error term is included in estimating source wavelet from received signals. In spite of the object function error, the diffraction tomography assist for interpretation of subsurface as if conducted with travel time tomography. And the fracture model was tested, 1st born diffraction tomographic image is poor because of limited view angle coverage and violation of week scatter assumption, but the filtered image resolve the fracture somewhat better. The tested diffraction tomography image confirms effectiveness of filter for enhancing resolution. (author). 14

Diffraction and Unitarity

Science.gov (United States)

Dremin, I. M.

I begin with a tribute to V.N. Gribov and then come to a particular problem which would be of interest for him. His first paper on reggeology was devoted to elastic scatterings of hadrons. Here, using the unitarity relation in combination with experimental data about the elastic scattering in the diffraction cone, I show how the shape and the darkness of the interaction region of colliding protons change with the increase of their energies. In particular, the collisions become fully absorptive at small impact parameters at LHC energies that results in some special features of inelastic processes as well. The possible evolution with increasing energy of the shape from the dark core at the LHC to the fully transparent one at higher energies is discussed. It implies that the terminology of the black disk would be replaced by the black torus.

Diffraction from relief gratings on a biomimetic elastomer cast

International Nuclear Information System (INIS)

Guerrero, Raphael A.; Aranas, Erika B.

2010-01-01

Biomimetic optical elements combine the optimized designs of nature with the versatility of materials engineering. We employ a beetle carapace as the template for fabricating relief gratings on an elastomer substrate. Biological surface features are successfully replicated by a direct casting procedure. Far-field diffraction effects are discussed in terms of the Fraunhofer approximation in Fourier space.

Non-destructive analysis of micro texture and grain boundary character from X-ray diffraction contrast tomography

DEFF Research Database (Denmark)

King, A.; Herbig, M.; Ludwig, W.

2010-01-01

Recent advances in synchrotron based X-ray imaging and diffraction techniques offer interesting new possibilities for mapping 3D grain shapes and crystallographic orientations in different classes of polycrystalline materials. X-ray diffraction contrast tomography (DCT) is a monochromatic beam...... imaging technique combining the principles of X-ray micro-tomography and three-dimensional X-ray diffraction microscopy (3DXRD). DCT provides simultaneous access to 3D grain shape, crystallographic orientation and attenuation coefficient distribution at the micrometer length scale. The microtexture...

Commercial air travel and in-flight pulmonary hypertension.

Science.gov (United States)

Smith, Thomas G; Chang, Rae W; Robbins, Peter A; Dorrington, Keith L

2013-01-01

It has recently been shown that commercial air travel triggers hypoxic pulmonary vasoconstriction and modestly increases pulmonary artery pressure in healthy passengers. There is large interindividual variation in hypoxic pulmonary vasoreactivity, and some passengers may be at risk of developing flight-induced pulmonary hypertension, with potentially dangerous consequences. This study sought to determine whether it is possible for a susceptible passenger to develop pulmonary hypertension in response to a routine commercial flight. Using in-flight echocardiography, a passenger was studied during a 6-h commercial flight from London to Dubai. The passenger was generally well and frequently traveled by air, but had been diagnosed with Chuvash polycythemia, a genetic condition that is associated with increased hypoxic pulmonary vasoreactivity. Hematocrit had been normalized with regular venesection. During the flight, arterial oxygen saturation fell to a minimum of 96% and systolic pulmonary artery pressure (sPAP) rapidly increased into the pulmonary hypertensive range. The in-flight increase in sPAP was 50%, reaching a peak of 45 mmHg. This study has established that an asymptomatic but susceptible passenger can rapidly develop in-flight pulmonary hypertension even during a medium-haul flight. Prospective passengers at risk from such responses, including those who have cardiopulmonary disease or increased hypoxic pulmonary vasoreactivity, could benefit from preflight evaluation with a hypoxia altitude simulation test combined with simultaneous echocardiography (HAST-echo). The use of in-flight supplementary oxygen should be considered for susceptible individuals, including all patients diagnosed with Chuvash polycythemia.

Diffraction and Total Cross-Section at the Tevatron and the LHC

CERN Document Server

Deile, M; Aurola, A; Avati, V; Berardi, V; Bottigli, U; Bozzo, M; Brucken, E; Buzzo, A; Calicchio, M; Capurro, F; Catanesi, M G; Ciocci, M A; Cuneo, S; Da Vià, C; Dimovasili, E; Eggert, K; Eraluoto, M; Ferro, F; Giachero, A; Guillaud, J P; Hasi, J; Haug, F; Heino, J; Hilden, T; Jarron, P; Kalliopuska, J; Kaspar, J; Kempa, J; Kenney, C; Kok, A; Kundrát, V; Kurvinen, K; Lami, S; Lamsa, J; Latino, G; Lauhakangas, R; Lippmaa, J; Lokajícek, M; Lo Vetere, M; Macina, D; Macri, M; Meucci, M; Minutoli, S; Morelli, A; Musico, P; Negri, M; Niewiadomski, H; Noschis, E; Ojala, J; Oljemark, F; Orava, R; Oriunno, M; Österberg, K; Paoletti, R; Parker, S; Perrot, Anne Laure; Radermacher, E; Radicioni, E; Robutti, E; Ropelewski, Leszek; Ruggiero, G; Saarikko, H; Sanguinetti, G; Santroni, A; Saramad, S; Sauli, Fabio; Scribano, A; Sette, G; Smotlacha, J; Snoeys, W; Taylor, C; Toppinen, A; Turini, N; Van Remortel, N; Verardo, L; Verdier, A; Watts, S; Whitmore, J

2006-01-01

At the Tevatron, the total p_bar-p cross-section has been measured by CDF at 546 GeV and 1.8 TeV, and by E710/E811 at 1.8 TeV. The two results at 1.8 TeV disagree by 2.6 standard deviations, introducing big uncertainties into extrapolations to higher energies. At the LHC, the TOTEM collaboration is preparing to resolve the ambiguity by measuring the total p-p cross-section with a precision of about 1 %. Like at the Tevatron experiments, the luminosity-independent method based on the Optical Theorem will be used. The Tevatron experiments have also performed a vast range of studies about soft and hard diffractive events, partly with antiproton tagging by Roman Pots, partly with rapidity gap tagging. At the LHC, the combined CMS/TOTEM experiments will carry out their diffractive programme with an unprecedented rapidity coverage and Roman Pot spectrometers on both sides of the interaction point. The physics menu comprises detailed studies of soft diffractive differential cross-sections, diffractive structure func...

Nanostructured diffractive optical devices for soft X-ray microscopes

CERN Document Server

Hambach, D; Schneider, G

2001-01-01

The new transmission X-ray microscope (TXM) installed at the BESSY II electron storage ring uses an off-axis transmission zone plate (OTZ) as diffractive and focusing element of the condenser-monochromator setup. A high resolution micro-zone plate (MZP) forms a magnified image on a CCD-detector. Both, the OTZ with an active area of up to 24 mm sup 2 and the MZP with zone widths as small as 25 nm are generated by a process including electron beam lithography (EBL), dry etching and subsequent electroplating of nickel on top of silicon membrane substrates with about 100-150 nm thickness. The combination of a larger zone width and the usage of nickel zone structures allows to increase the diffraction efficiency of the condenser element at least by a factor of 3 compared to the earlier used KZP7 condenser zone plate in the TXM at BESSY I. Groove diffraction efficiencies of 21.6% and 14.7% were measured for MZP objectives with 40 and 25 nm outermost zone width, respectively.

Inclusive Measurement of Diffractive Deep-Inelastic Scattering at HERA

CERN Document Server

Aaron, F.D.

2012-07-18

The diffractive process ep \\rightarrow eXY, where Y denotes a proton or its low mass excitation with MY < 1.6 GeV, is studied with the H1 experiment at HERA. The analysis is restricted to the phase space region of the photon virtuality 3 \\leq Q2 \\leq 1600 GeV2, the square of the four-momentum transfer at the proton vertex |t| < 1.0 GeV2 and the longitudinal momentum fraction of the incident proton carried by the colourless exchange xIP < 0.05. Triple differential cross sections are measured as a function of xIP, Q2 and beta = x/xIP where x is the Bjorken scaling variable. These measurements are made after selecting diffractive events by demanding a large empty rapidity interval separating the final state hadronic systems X and Y . High statistics measurements covering the data taking periods 1999-2000 and 2004-2007 are combined with previously published results in order to provide a single set of diffractive cross sections from the H1 experiment using the large rapidity gap selection method. The comb...

Spectroscopic imaging, diffraction, and holography with x-ray photoemission

Energy Technology Data Exchange (ETDEWEB)

1992-02-01

X-ray probes are capable of determining the spatial structure of an atom in a specific chemical state, over length scales from about a micron all the way down to atomic resolution. Examples of these probes include photoemission microscopy, energy-dependent photoemission diffraction, photoelectron holography, and X-ray absorption microspectroscopy. Although the method of image formation, chemical-state sensitivity, and length scales can be very different, these X-ray techniques share a common goal of combining a capability for structure determination with chemical-state specificity. This workshop will address recent advances in holographic, diffraction, and direct imaging techniques using X-ray photoemission on both theoretical and experimental fronts. A particular emphasis will be on novel structure determinations with atomic resolution using photoelectrons.

Spectroscopic imaging, diffraction, and holography with x-ray photoemission

International Nuclear Information System (INIS)

1992-02-01

X-ray probes are capable of determining the spatial structure of an atom in a specific chemical state, over length scales from about a micron all the way down to atomic resolution. Examples of these probes include photoemission microscopy, energy-dependent photoemission diffraction, photoelectron holography, and X-ray absorption microspectroscopy. Although the method of image formation, chemical-state sensitivity, and length scales can be very different, these X-ray techniques share a common goal of combining a capability for structure determination with chemical-state specificity. This workshop will address recent advances in holographic, diffraction, and direct imaging techniques using X-ray photoemission on both theoretical and experimental fronts. A particular emphasis will be on novel structure determinations with atomic resolution using photoelectrons

Diffractive optics for industrial and commercial applications

Energy Technology Data Exchange (ETDEWEB)

Turunen, J. [Joensuu Univ. (Finland); Wyrowski, F. [eds.] [Jena Univ. (Germany)

1997-12-31

The following topics were dealt with: diffractive optics, diffraction gratings, optical system design with diffractive optics, continuous-relief diffractive lenses and microlens arrays, diffractive bifocal intraocular lenses, diffractive laser resonators, diffractive optics for semiconductor lasers, diffractive elements for optical image processing, photorefractive crystals in optical measurement systems, subwavelenth-structured elements, security applications, diffractive optics for solar cells, holographic microlithography. 999 refs.

Analytical properties of time-of-flight PET data

Energy Technology Data Exchange (ETDEWEB)

Cho, Sanghee; Ahn, Sangtae; Quanzheng, Li; Leahy, Richard M [Signal and Image Processing Institute, University of Southern California, Los Angeles, CA 90089 (United States)], E-mail: leahy@sipi.usc.edu

2008-06-07

We investigate the analytical properties of time-of-flight (TOF) positron emission tomography (PET) sinograms, where the data are modeled as line integrals weighted by a spatially invariant TOF kernel. First, we investigate the Fourier transform properties of 2D TOF data and extend the 'bow-tie' property of the 2D Radon transform to the time-of-flight case. Second, we describe a new exact Fourier rebinning method, TOF-FOREX, based on the Fourier transform in the time-of-flight variable. We then combine TOF-FOREX rebinning with a direct extension of the projection slice theorem to TOF data, to perform fast 3D TOF PET image reconstruction. Finally, we illustrate these properties using simulated data.

Analytical properties of time-of-flight PET data

Science.gov (United States)

Cho, Sanghee; Ahn, Sangtae; Li, Quanzheng; Leahy, Richard M.

2008-06-01

We investigate the analytical properties of time-of-flight (TOF) positron emission tomography (PET) sinograms, where the data are modeled as line integrals weighted by a spatially invariant TOF kernel. First, we investigate the Fourier transform properties of 2D TOF data and extend the 'bow-tie' property of the 2D Radon transform to the time-of-flight case. Second, we describe a new exact Fourier rebinning method, TOF-FOREX, based on the Fourier transform in the time-of-flight variable. We then combine TOF-FOREX rebinning with a direct extension of the projection slice theorem to TOF data, to perform fast 3D TOF PET image reconstruction. Finally, we illustrate these properties using simulated data.

Analytical properties of time-of-flight PET data

International Nuclear Information System (INIS)

Cho, Sanghee; Ahn, Sangtae; Li Quanzheng; Leahy, Richard M

2008-01-01

We investigate the analytical properties of time-of-flight (TOF) positron emission tomography (PET) sinograms, where the data are modeled as line integrals weighted by a spatially invariant TOF kernel. First, we investigate the Fourier transform properties of 2D TOF data and extend the 'bow-tie' property of the 2D Radon transform to the time-of-flight case. Second, we describe a new exact Fourier rebinning method, TOF-FOREX, based on the Fourier transform in the time-of-flight variable. We then combine TOF-FOREX rebinning with a direct extension of the projection slice theorem to TOF data, to perform fast 3D TOF PET image reconstruction. Finally, we illustrate these properties using simulated data

Analytical properties of time-of-flight PET data

Energy Technology Data Exchange (ETDEWEB)

Cho, Sanghee; Ahn, Sangtae; Li Quanzheng; Leahy, Richard M [Signal and Image Processing Institute, University of Southern California, Los Angeles, CA 90089 (United States)], E-mail: leahy@sipi.usc.edu

2008-06-07

We investigate the analytical properties of time-of-flight (TOF) positron emission tomography (PET) sinograms, where the data are modeled as line integrals weighted by a spatially invariant TOF kernel. First, we investigate the Fourier transform properties of 2D TOF data and extend the 'bow-tie' property of the 2D Radon transform to the time-of-flight case. Second, we describe a new exact Fourier rebinning method, TOF-FOREX, based on the Fourier transform in the time-of-flight variable. We then combine TOF-FOREX rebinning with a direct extension of the projection slice theorem to TOF data, to perform fast 3D TOF PET image reconstruction. Finally, we illustrate these properties using simulated data.

Liquid contrabands classification based on energy dispersive X-ray diffraction and hybrid discriminant analysis

International Nuclear Information System (INIS)

YangDai, Tianyi; Zhang, Li

2016-01-01

Energy dispersive X-ray diffraction (EDXRD) combined with hybrid discriminant analysis (HDA) has been utilized for classifying the liquid materials for the first time. The XRD spectra of 37 kinds of liquid contrabands and daily supplies were obtained using an EDXRD test bed facility. The unique spectra of different samples reveal XRD's capability to distinguish liquid contrabands from daily supplies. In order to create a system to detect liquid contrabands, the diffraction spectra were subjected to HDA which is the combination of principal components analysis (PCA) and linear discriminant analysis (LDA). Experiments based on the leave-one-out method demonstrate that HDA is a practical method with higher classification accuracy and lower noise sensitivity than the other methods in this application. The study shows the great capability and potential of the combination of XRD and HDA for liquid contrabands classification.

Liquid contrabands classification based on energy dispersive X-ray diffraction and hybrid discriminant analysis

Energy Technology Data Exchange (ETDEWEB)

YangDai, Tianyi [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education (China); Zhang, Li, E-mail: zhangli@nuctech.com [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China); Key Laboratory of Particle & Radiation Imaging (Tsinghua University), Ministry of Education (China)

2016-02-01

Energy dispersive X-ray diffraction (EDXRD) combined with hybrid discriminant analysis (HDA) has been utilized for classifying the liquid materials for the first time. The XRD spectra of 37 kinds of liquid contrabands and daily supplies were obtained using an EDXRD test bed facility. The unique spectra of different samples reveal XRD's capability to distinguish liquid contrabands from daily supplies. In order to create a system to detect liquid contrabands, the diffraction spectra were subjected to HDA which is the combination of principal components analysis (PCA) and linear discriminant analysis (LDA). Experiments based on the leave-one-out method demonstrate that HDA is a practical method with higher classification accuracy and lower noise sensitivity than the other methods in this application. The study shows the great capability and potential of the combination of XRD and HDA for liquid contrabands classification.

Liquid contrabands classification based on energy dispersive X-ray diffraction and hybrid discriminant analysis

Science.gov (United States)

YangDai, Tianyi; Zhang, Li

2016-02-01

Energy dispersive X-ray diffraction (EDXRD) combined with hybrid discriminant analysis (HDA) has been utilized for classifying the liquid materials for the first time. The XRD spectra of 37 kinds of liquid contrabands and daily supplies were obtained using an EDXRD test bed facility. The unique spectra of different samples reveal XRD's capability to distinguish liquid contrabands from daily supplies. In order to create a system to detect liquid contrabands, the diffraction spectra were subjected to HDA which is the combination of principal components analysis (PCA) and linear discriminant analysis (LDA). Experiments based on the leave-one-out method demonstrate that HDA is a practical method with higher classification accuracy and lower noise sensitivity than the other methods in this application. The study shows the great capability and potential of the combination of XRD and HDA for liquid contrabands classification.

Dynamic Flight Simulation Utilizing High Fidelity CFD-Based Nonlinear Reduced Order Model, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The Nonlinear Dynamic Flight Simulation (NL-DFS) system will be developed in the Phase II project by combining the classical nonlinear rigid-body flight dynamics...

Diffraction at TOTEM

CERN Document Server

Antchev, G.; Avati, V.; Bagliesi, M.G.; Berardi, V.; Berretti, M.; Bottigli, U.; Bozzo, M.; Brucken, E.; Buzzo, A.; Cafagna, F.; Calicchio, M.; Catanesi, M.G.; Catastini, P.L.; Cecchi, R.; Ciocci, M.A.; Deile, M.; Dimovasili, E.; Eggert, K.; Eremin, V.; Ferro, F.; Garcia, F.; Giani, S.; Greco, V.; Heino, J.; Hilden, T.; Kaspar, J.; Kopal, J.; Kundrat, V.; Kurvinen, K.; Lami, S.; Latino, G.; Lauhakangas, R.; Lippmaa, E.; Lokajicek, M.; Lo Vetere, M.; Lucas Rodriguez, F.; Macri, M.; Magazzu, G.; Meucci, M.; Minutoli, S.; Niewiadomski, H.; Noschis, E.; Notarnicola, G.; Oliveri, E.; Oljemark, F.; Orava, R.; Oriunno, M.; Osterberg, K.; Palazzi, P.; Pedreschi, E.; Petajajarvi, J.; Quinto, M.; Radermacher, E.; Radicioni, E.; Ravotti, F.; Rella, G.; Robutti, E.; Ropelewski, L.; Ruggiero, G.; Rummel, A.; Saarikko, H.; Sanguinetti, G.; Santroni, A.; Scribano, A.; Sette, G.; Snoeys, W.; Spinella, F.; Squillacioti, P.; Ster, A.; Taylor, C.; Trummal, A.; Turini, N.; Whitmore, J.; Wu, J.

2009-01-01

The TOTEM experiment at the LHC measures the total proton-proton cross section with the luminosity-independent method and the elastic proton-proton cross-section over a wide |t|-range. It also performs a comprehensive study of diffraction, spanning from cross-section measurements of individual diffractive processes to the analysis of their event topologies. Hard diffraction will be studied in collaboration with CMS taking advantage of the large common rapidity coverage for charged and neutral particle detection and the large variety of trigger possibilities even at large luminosities. TOTEM will take data under all LHC beam conditions including standard high luminosity runs to maximize its physics reach. This contribution describes the main features of the TOTEM physics programme including measurements to be made in the early LHC runs. In addition, a novel scheme to extend the diffractive proton acceptance for high luminosity runs by installing proton detectors at IP3 is described.

The PIAA Coronagraph: Optical design and Diffraction Effects

Science.gov (United States)

Pluzhnik, E. A.; Guyon, O.; Ridgway, S.; Martinache, F.; Woodruff, R.; Blain, C.; Galicher, R.

2005-12-01

Properly apodized pupils are suitable for high dynamical range imaging of extrasolar terrestrial planets. Phase-induced amplitude apodization (PIAA) of the telescope pupil (Guyon 2003) combines the advantages of classical pupil apodization with full throughput, no loss of angular resolution and low chromaticity. Diffraction propagation effects can decrease both the achieved contrast and the spectral bandwidth of the coronagraph. We show here how the diffraction effects in the PIAA optics can be corrected by an appropriate optical design. The proposed hybrid coronagraph design preserves the 10-10 PSF contrast at ≈ 1.5 λ /d required for efficient exoplanet imaging over the whole visible spectrum. This work was carried out under JPL contract numbers 1254445 and 1257767 for Development of Technologies for the Terrestrial Planet Finder Mission, with the support and hospitality of the National Astronomical Observatory of Japan.

Nonlinear and diffraction effects in propagation of N-waves in randomly inhomogeneous moving media.

Science.gov (United States)

Averiyanov, Mikhail; Blanc-Benon, Philippe; Cleveland, Robin O; Khokhlova, Vera

2011-04-01

Finite amplitude acoustic wave propagation through atmospheric turbulence is modeled using a Khokhlov-Zabolotskaya-Kuznetsov (KZK)-type equation. The equation accounts for the combined effects of nonlinearity, diffraction, absorption, and vectorial inhomogeneities of the medium. A numerical algorithm is developed which uses a shock capturing scheme to reduce the number of temporal grid points. The inhomogeneous medium is modeled using random Fourier modes technique. Propagation of N-waves through the medium produces regions of focusing and defocusing that is consistent with geometrical ray theory. However, differences up to ten wavelengths are observed in the locations of fist foci. Nonlinear effects are shown to enhance local focusing, increase the maximum peak pressure (up to 60%), and decrease the shock rise time (about 30 times). Although the peak pressure increases and the rise time decreases in focal regions, statistical analysis across the entire wavefront at a distance 120 wavelengths from the source indicates that turbulence: decreases the mean time-of-flight by 15% of a pulse duration, decreases the mean peak pressure by 6%, and increases the mean rise time by almost 100%. The peak pressure and the arrival time are primarily governed by large scale inhomogeneities, while the rise time is also sensitive to small scales.

Rietveld analysis using powder diffraction data with anomalous scattering effect obtained by focused beam flat sample method

International Nuclear Information System (INIS)

Tanaka, Masahiko; Katsuya, Yoshio; Sakata, Osami

2016-01-01

Focused-beam flat-sample method (FFM) is a new trial for synchrotron powder diffraction method, which is a combination of beam focusing optics, flat shape powder sample and area detectors. The method has advantages for X-ray diffraction experiments applying anomalous scattering effect (anomalous diffraction), because of 1. Absorption correction without approximation, 2. High intensity X-rays of focused incident beams and high signal noise ratio of diffracted X-rays 3. Rapid data collection with area detectors. We applied the FFM to anomalous diffraction experiments and collected synchrotron X-ray powder diffraction data of CoFe_2O_4 (inverse spinel structure) using X-rays near Fe K absorption edge, which can distinguish Co and Fe by anomalous scattering effect. We conducted Rietveld analyses with the obtained powder diffraction data and successfully determined the distribution of Co and Fe ions in CoFe_2O_4 crystal structure.

Dynamic processes of domain switching in lead zirconate titanate under cyclic mechanical loading by in situ neutron diffraction

International Nuclear Information System (INIS)

Pojprapai, Soodkhet; Luo, Zhenhua; Clausen, Bjorn; Vogel, Sven C.; Brown, Donald W.; Russel, Jennifer; Hoffman, Mark

2010-01-01

The performance of ferroelectric ceramics is governed by the ability of domains to switch. A decrease in the switching ability can lead to degradation of the materials and failure of ferroelectric devices. In this work the dynamic properties of domain reorientation are studied. In situ time-of-flight neutron diffraction is used to probe the evolution of ferroelastic domain texture under mechanical cyclic loading in bulk lead zirconate titanate ceramics. The high sensitivity of neutron diffraction to lattice strain is exploited to precisely analyze the change of domain texture and strain through a full-pattern Rietveld method. These results are then used to construct a viscoelastic model, which explains the correlation between macroscopic phenomena (i.e. creep and recovered deformation) and microscopic dynamic behavior (i.e. ferroelastic switching, lattice strain).

Diffraction radiation from relativistic particles

CERN Document Server

Potylitsyn, Alexander Petrovich; Strikhanov, Mikhail Nikolaevich; Tishchenko, Alexey Alexandrovich

2010-01-01

This book deals with diffraction radiation, which implies the boundary problems of electromagnetic radiation theory. Diffraction radiation is generated when a charged particle moves in a vacuum near a target edge. Diffraction radiation of non-relativistic particles is widely used to design intense emitters in the cm wavelength range. Diffraction radiation from relativistic charged particles is important for noninvasive beam diagnostics and design of free electron lasers based on Smith-Purcell radiation which is diffraction radiation from periodic structures. Different analytical models of diffraction radiation and results of recent experimental studies are presented in this book. The book may also serve as guide to classical electrodynamics applications in beam physics and electrodynamics. It can be of great use for young researchers to develop skills and for experienced scientists to obtain new results.

Diffraction radiation from relativistic particles

International Nuclear Information System (INIS)

Potylitsyn, Alexander Petrovich; Ryazanov, Mikhail Ivanovich; Strikhanov, Mikhail Nikolaevich; Tishchenko, Alexey Alexandrovich

2010-01-01

This book deals with diffraction radiation, which implies the boundary problems of electromagnetic radiation theory. Diffraction radiation is generated when a charged particle moves in a vacuum near a target edge. Diffraction radiation of non-relativistic particles is widely used to design intense emitters in the cm wavelength range. Diffraction radiation from relativistic charged particles is important for noninvasive beam diagnostics and design of free electron lasers based on Smith-Purcell radiation which is diffraction radiation from periodic structures. Different analytical models of diffraction radiation and results of recent experimental studies are presented in this book. The book may also serve as guide to classical electrodynamics applications in beam physics and electrodynamics. It can be of great use for young researchers to develop skills and for experienced scientists to obtain new results. (orig.)

Spin transitions in La{sub 0.7} Ba{sub 0.3}CoO{sub 3} thin films revealed by combining Raman spectroscopy and X-ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Othmen, Zied; Oueslati, Meherzi [Unité Nanomatériaux et Photonique, Faculty of Sciences of Tunis, Tunis El-Manar University, 2092 Tunis (Tunisia); Copie, Olivier; Gemeiner, Pascale; Dkhil, Brahim [Laboratoire Structures, Propriétés et Modélisation des Solides, Centrale Supélec, CNRS-UMR 8580, Université Paris-Saclay (France); Daoudi, Kais [Unité Nanomatériaux et Photonique, Faculty of Sciences of Tunis, Tunis El-Manar University, 2092 Tunis (Tunisia); Department of Applied Physics and Astronomy, College of Sciences, University of Sharjah, P.O. Box 27272, Sharjah (United Arab Emirates); Boudard, Michel [Univ. Grenoble Alpes, LMGP, F-38000 Grenoble (France)

2016-07-07

In cobaltite, the spin states transitions of Co{sup 3+/4+} ions govern the magnetic and electronic conduction properties. These transitions are strain-sensitive and can be varied using external parameters, including temperature, hydrostatic pressure, or chemical stresses through ionic substitutions. In this work, using temperature dependent Raman spectroscopy and X-ray diffraction, the epitaxial strain effects on both structural and vibrational properties of La{sub 0.7} Ba{sub 0.3} CoO{sub 3} (LBCO) cobaltite thin films are investigated. All Raman active phonon modes as well as the structure are found to be strongly affected. Both Raman modes and lattice parameter evolutions show temperature changes correlated with magnetic and electronic transitions properties. Combining Raman spectroscopy and X-ray diffraction appears as a powerful approach to probe the spin transition in thin film cobaltite. Our results provide insight into strong spin-charge-phonon coupling in LBCO thin film. This coupling manifests as vibrational transition with temperature in the Raman spectra near the ferromagnetic spin ordered transition at 220 K.

Aircraft digital flight control technical review

Science.gov (United States)

Davenport, Otha B.; Leggett, David B.

1993-01-01

The Aircraft Digital Flight Control Technical Review was initiated by two pilot induced oscillation (PIO) incidents in the spring and summer of 1992. Maj. Gen. Franklin (PEO) wondered why the Air Force development process for digital flight control systems was not preventing PIO problems. Consequently, a technical review team was formed to examine the development process and determine why PIO problems continued to occur. The team was also to identify the 'best practices' used in the various programs. The charter of the team was to focus on the PIO problem, assess the current development process, and document the 'best practices.' The team reviewed all major USAF aircraft programs with digital flight controls, specifically, the F-15E, F-16C/D, F-22, F-111, C-17, and B-2. The team interviewed contractor, System Program Office (SPO), and Combined Test Force (CTF) personnel on these programs. The team also went to NAS Patuxent River to interview USN personnel about the F/A-18 program. The team also reviewed experimental USAF and NASA systems with digital flight control systems: X-29, X-31, F-15 STOL and Maneuver Technology Demonstrator (SMTD), and the Variable In-Flight Stability Test Aircraft (VISTA). The team also discussed the problem with other experts in the field including Ralph Smith and personnel from Calspan. The major conclusions and recommendations from the review are presented.

Diffractive DIS: Where are we?

International Nuclear Information System (INIS)

Nikolaev, N.N.

2001-01-01

A brief review of the modern QCD theory of diffractive DIS is given. The recent progress has been remarkably rapid, all the principal predictions from the color dipole approach to diffraction - the (Q 2 + m V 2 ) scaling, the pattern of SCHNC, shrinkage of the diffraction cone in hard diffractive DIS, the strong impact of longitudinal gluons in inclusive J/Ψ production at Tevatron - have been confirmed experimentally

Diffraction dissociation

International Nuclear Information System (INIS)

Abarbanel, H.

1972-01-01

An attempt is made to analyse the present theoretical situation in the field of diffraction scattering. Two not yet fully answered questions related with a typical diffraction process AB→CD, namely: what is the structure of the transition matrix elements, and what is the structure of the exchange mechanism responsible for the scattering, are formulated and various proposals for answers are reviewed. Interesting general statement that the products (-1)sup(J)P, where J and P are respectively spin and parity, is conserved at each vertex has been discussed. The exchange mechanism in diffractive scattering has been considered using the language of the complex J-plane as the most appropriate. The known facts about the exchange mechanism are recalled and several routs to way out are proposed. The idea to consider the moving pole and associated branch points as like a particle and the associated two and many particle unitarity cuts is described in more details. (S.B.)

Neutron time-of-flight techniques for investigation of the extinction effect

International Nuclear Information System (INIS)

Niimura, N.; Tomiyoshi, S.; Takahashi, J.; Harada, J.

1975-01-01

An application of the time-of-flight neutron diffraction technique to an investigation of the nature of the extinction effect in a single-crystal specimen is given. It is shown that the wavelength dependence of the extinction can be easily obtained by changing the scattering angle. An estimation of the extinction factor for a CuCl single crystal is given as an example and a comparison of the results with recent extinction theory [Becker and Coppens. Acta Cryst.(1974). A30, 129-147; 148-153] is made. (Auth.)

Neutron diffraction from holographic gratings in PMMA

International Nuclear Information System (INIS)

Havermeyer, F.; Kraetzig, E.; Rupp, R.A.; Schubert, D.W.

1999-01-01

Complete text of publication follows. By definition photorefractive materials change the refractive index for light under the action of light. Using the spatially modulated light intensity pattern from the interference of two plane waves, volume phase gratings with accurately defined spacings can be produced. Depending on the material there are many physical origins for these gratings, but in most cases they are linked to a density modulation and, consequently, to a refractive index grating for neutrons. By diffraction of light or neutrons from such gratings even small refractive index changes down to Δn ∼ 10 -7 - 10 -9 can be measured. In our photopolymer system PMMA/MMA (poly(methyl methacrylate) with a content of 10-20% of the residual monomer methyl methacrylate) inhomogeneous illumination leads to local post-polymerisation processes of the residual monomer. The resulting light-optical refractive index grating is caused by the modulation of the monomer/polymer ratio as well as by the modulation of the total density. Only by the unique combination of methods for light and neutron diffraction, available at HOLONS (Holography and Neutron Scattering, instrument at the GKSS research centre), both contributions can be separated. We discuss the angular dependence of the neutron diffraction efficiency for weakly and strongly (efficiencies up to 60% have been achieved) modulated gratings and propose a simple model for the evaluation of the gratings. (author)

Texture analysis of a friction stir processed 6061-T6 aluminum alloy using neutron diffraction

International Nuclear Information System (INIS)

Woo, W.; Choo, H.; Brown, D.W.; Vogel, S.C.; Liaw, P.K.; Feng, Z.

2006-01-01

Time-of-flight neutron diffraction was used to investigate the texture changes in friction stir-processed (FSP) 6061-T6 aluminum alloy plates. Two different specimens were prepared with the purpose of separating the effects of frictional heating and severe plastic deformation on the changes of the preferred orientation in the as-received rolled plates: a plate processed with both stirring pin and tool shoulder, i.e., a regular FSP plate subjected to both severe plastic deformation and frictional heating (Case 1); and a plate processed only with the tool shoulder, i.e., subjected mainly to frictional heating (Case 2). The diffraction peak intensities provide insights into the texture variations at various locations across the centerline and through the thickness of the FSP plates. Comparison of the texture variations between Cases 1 and 2 clearly shows that the severe plastic deformation from the stirring pin affects the preferred orientation during the FSP, while heating alone from the tool shoulder has little effect

Spatially resolved determination of lattice distortions in silicon nanostructures by means of electron-backscattering diffraction

International Nuclear Information System (INIS)

Krause, Michael

2013-01-01

In the submitted thesis, a novel combined approach of both focused ion beam (FIB) based target preparation and strain determination using electron backscatter diffraction (EBSD) in semiconductor nanostructures is presented. In the first part, a powerful cross-correlation algorithm for detecting small feature shifts within EBSD patterns and, consequently, determining the strain, is presented. The corresponding strain sensitivity is demonstrated using dynamically simulated diffraction patterns. Furthermore, novel procedures for automated pattern analysis are introduced. Results of systematic studies concerning the influence of ion species, ion energy and dose density on the surface quality of silicon surfaces are presented in the second part. For that matter, the assessment of surface amorphization and rippling is based on high resolution microstructural diagnostics (TEM, AFM, Raman) and molecular dynamics simulation. The high application potential of combined FIB preparation and strain analysis using EBSD is exemplarily demonstrated for a 60 nm thick sSOI-sample. The good agreement with established techniques like Raman spectroscopy and X-ray diffraction is also shown.

In-Flight Sleep of Flight Crew During a 7-hour Rest Break: Implications for Research and Flight Safety

Science.gov (United States)

Signal, T. Leigh; Gander, Philippa H.; van den Berg, Margo J.; Graeber, R. Curtis

2013-01-01

Study Objectives: To assess the amount and quality of sleep that flight crew are able to obtain during flight, and identify factors that influence the sleep obtained. Design: Flight crew operating flights between Everett, WA, USA and Asia had their sleep recorded polysomnographically for 1 night in a layover hotel and during a 7-h in-flight rest opportunity on flights averaging 15.7 h. Setting: Layover hotel and in-flight crew rest facilities onboard the Boeing 777-200ER aircraft. Participants: Twenty-one male flight crew (11 Captains, mean age 48 yr and 10 First Officers, mean age 35 yr). Interventions: N/A. Measurements and Results: Sleep was recorded using actigraphy during the entire tour of duty, and polysomnographically in a layover hotel and during the flight. Mixed model analysis of covariance was used to determine the factors affecting in-flight sleep. In-flight sleep was less efficient (70% vs. 88%), with more nonrapid eye movement Stage 1/Stage 2 and more frequent awakenings per h (7.7/h vs. 4.6/h) than sleep in the layover hotel. In-flight sleep included very little slow wave sleep (median 0.5%). Less time was spent trying to sleep and less sleep was obtained when sleep opportunities occurred during the first half of the flight. Multivariate analyses suggest age is the most consistent factor affecting in-flight sleep duration and quality. Conclusions: This study confirms that even during long sleep opportunities, in-flight sleep is of poorer quality than sleep on the ground. With longer flight times, the quality and recuperative value of in-flight sleep is increasingly important for flight safety. Because the age limit for flight crew is being challenged, the consequences of age adversely affecting sleep quantity and quality need to be evaluated. Citation: Signal TL; Gander PH; van den Berg MJ; Graeber RC. In-flight sleep of flight crew during a 7-hour rest break: implications for research and flight safety. SLEEP 2013;36(1):109–115. PMID:23288977

Deformation behaviors of aluminum alloys for automobile parts studied by neutron diffraction

International Nuclear Information System (INIS)

Katayanagi, Kazue; Morita, Kensuke; Tomota, Yo; Kamiyama, Takashi; Terakado, Katsuyoshi

2008-01-01

In situ time of flight neutron diffraction measurements during tension test were performed for three Al-Si alloys with different microstructures including hot-forged (AHS 2), T 6 heat-treated (AHS 2-T 6) and die-cast (ACD 12) specimens. Strength and work-hardening behaviors of these specimens are investigated by evaluating phase stresses, i.e., stress partitioning between Si and the Al matrix as well as intergranular stresses of [hkl] oriented family grains in the component phases. It is revealed that Si particles embedded in the Al matrix play a role of the hard second phase. The size and shape of the Si particles affect work hardening and fracture of the alloys. (author)

Measurements of transient electron density distributions by femtosecond X-ray diffraction

International Nuclear Information System (INIS)

Freyer, Benjamin

2013-01-01

This thesis concerns measurements of transient charge density maps by femtosecond X-ray diffraction. Different X-ray diffraction methods will be considered, particularly with regard to their application in femtosecond X-ray diffraction. The rotation method is commonly used in stationary X-ray diffraction. In the work in hand an X-ray diffraction experiment is demonstrated, which combines the method with ultrafast X-ray pulses. This experiment is the first implementation which makes use of the rotation method to map transient intensities of a multitude of Bragg reflections. As a prototype material Bismuth is used, which previously was studied frequently by femtosecond X-ray diffraction by measuring Bragg reflections successively. The experimental results of the present work are compared with the literature data. In the second part a powder-diffraction experiment will be presented, which is used to study the dynamics of the electron-density distribution on ultrafast time scales. The experiment investigates a transition metal complex after photoexcitation of the metal to ligand charge transfer state. Besides expected results, i. e. the change of the bond length between the metal and the ligand and the transfer of electronic charge from the metal to the ligand, a strong contribution of the anion to the charge transfer was found. Furthermore, the charge transfer has predominantly a cooperative character. That is, the excitation of a single complex causes an alteration of the charge density of several neighboring units. The results show that more than 30 transition-metal complexes and 60 anions contribute to the charge transfer. This collective response is a consequence of the strong coulomb interactions of the densely packed ions.

Monocular Vision System for Fixed Altitude Flight of Unmanned Aerial Vehicles

Directory of Open Access Journals (Sweden)

Kuo-Lung Huang

2015-07-01

Full Text Available The fastest and most economical method of acquiring terrain images is aerial photography. The use of unmanned aerial vehicles (UAVs has been investigated for this task. However, UAVs present a range of challenges such as flight altitude maintenance. This paper reports a method that combines skyline detection with a stereo vision algorithm to enable the flight altitude of UAVs to be maintained. A monocular camera is mounted on the downside of the aircraft’s nose to collect continuous ground images, and the relative altitude is obtained via a stereo vision algorithm from the velocity of the UAV. Image detection is used to obtain terrain images, and to measure the relative altitude from the ground to the UAV. The UAV flight system can be set to fly at a fixed and relatively low altitude to obtain the same resolution of ground images. A forward-looking camera is mounted on the upside of the aircraft’s nose. In combination with the skyline detection algorithm, this helps the aircraft to maintain a stable flight pattern. Experimental results show that the proposed system enables UAVs to obtain terrain images at constant resolution, and to detect the relative altitude along the flight path.

Electron diffraction from carbon nanotubes

International Nuclear Information System (INIS)

Qin, L-C

2006-01-01

The properties of a carbon nanotube are dependent on its atomic structure. The atomic structure of a carbon nanotube can be defined by specifying its chiral indices (u, v), that specify its perimeter vector (chiral vector), with which the diameter and helicity are also determined. The fine electron beam available in a modern transmission electron microscope (TEM) offers a unique probe to reveal the atomic structure of individual nanotubes. This review covers two aspects related to the use of the electron probe in the TEM for the study of carbon nanotubes: (a) to understand the electron diffraction phenomena for inter-pretation of the electron diffraction patterns of carbon nanotubes and (b) to obtain the chiral indices (u, v), of the carbon nanotubes from the electron diffraction patterns. For a nanotube of a given structure, the electron scattering amplitude from the carbon nanotube is first described analytically in closed form using the helical diffraction theory. From a known structure as given by the chiral indices (u, v), its electron diffraction pattern can be calculated and understood. The reverse problem, i.e. assignment of the chiral indices from an electron diffraction pattern of a carbon nanotube, is approached from the relationship between the electron scattering intensity distribution and the chiral indices (u, v). We show that electron diffraction patterns can provide an accurate and unambiguous assignment of the chiral indices of carbon nanotubes. The chiral indices (u, v) can be read indiscriminately with a high accuracy from the intensity distribution on the principal layer lines in an electron diffraction pattern. The symmetry properties of electron diffraction from carbon nanotubes and the electron diffraction from deformed carbon nanotubes are also discussed in detail. It is shown that 2mm symmetry is always preserved for single-walled carbon nanotubes, but it can break down for multiwalled carbon nanotubes under some special circumstances

Application of focused-beam flat-sample method to synchrotron powder X-ray diffraction with anomalous scattering effect

International Nuclear Information System (INIS)

Tanaka, M; Katsuya, Y; Matsushita, Y

2013-01-01

The focused-beam flat-sample method (FFM), which is a method for high-resolution and rapid synchrotron X-ray powder diffraction measurements by combination of beam focusing optics, a flat shape sample and an area detector, was applied for diffraction experiments with anomalous scattering effect. The advantages of FFM for anomalous diffraction were absorption correction without approximation, rapid data collection by an area detector and good signal-to-noise ratio data by focusing optics. In the X-ray diffraction experiments of CoFe 2 O 4 and Fe 3 O 4 (By FFM) using X-rays near the Fe K absorption edge, the anomalous scattering effect between Fe/Co or Fe 2+ /Fe 3+ can be clearly detected, due to the change of diffraction intensity. The change of observed diffraction intensity as the incident X-ray energy was consistent with the calculation. The FFM is expected to be a method for anomalous powder diffraction.

Rietveld analysis using powder diffraction data with anomalous scattering effect obtained by focused beam flat sample method

Energy Technology Data Exchange (ETDEWEB)

Tanaka, Masahiko, E-mail: masahiko@spring8.or.jp; Katsuya, Yoshio, E-mail: katsuya@spring8.or.jp; Sakata, Osami, E-mail: SAKATA.Osami@nims.go.jp [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science 1-1-1 Kouto, Sayo, Hyogo 679-5198 (Japan)

2016-07-27

Focused-beam flat-sample method (FFM) is a new trial for synchrotron powder diffraction method, which is a combination of beam focusing optics, flat shape powder sample and area detectors. The method has advantages for X-ray diffraction experiments applying anomalous scattering effect (anomalous diffraction), because of 1. Absorption correction without approximation, 2. High intensity X-rays of focused incident beams and high signal noise ratio of diffracted X-rays 3. Rapid data collection with area detectors. We applied the FFM to anomalous diffraction experiments and collected synchrotron X-ray powder diffraction data of CoFe{sub 2}O{sub 4} (inverse spinel structure) using X-rays near Fe K absorption edge, which can distinguish Co and Fe by anomalous scattering effect. We conducted Rietveld analyses with the obtained powder diffraction data and successfully determined the distribution of Co and Fe ions in CoFe{sub 2}O{sub 4} crystal structure.

Expression, purification and preliminary diffraction studies of PhnP

International Nuclear Information System (INIS)

Podzelinska, Kateryna; He, Shumei; Soares, Alexei; Zechel, David; Hove-Jensen, Bjarne; Jia, Zongchao

2008-01-01

PhnP, a member of the C—P lyase pathway, was crystallized by the sitting-drop vapour-diffusion method and the initial diffraction-pattern analysis is reported. PhnP belongs to a 14-gene operon that supports the growth of Escherichia coli on alkylphosphonates as a sole source of phosphorus; however, the exact biochemistry of phosphonate degradation by this pathway is poorly understood. The protein was recombinantly expressed in Escherichia coli and purified to homogeneity. Sitting-drop vapour diffusion in combination with microseeding was used to obtain crystals that were suitable for X-ray diffraction. Data were collected to 1.3 Å and the crystals belonged to space group C2, with unit-cell parameters a = 111.65, b = 75.41, c = 83.23 Å, α = γ = 90, β = 126.3°

In-flight sleep of flight crew during a 7-hour rest break: implications for research and flight safety.

Science.gov (United States)

Signal, T Leigh; Gander, Philippa H; van den Berg, Margo J; Graeber, R Curtis

2013-01-01

To assess the amount and quality of sleep that flight crew are able to obtain during flight, and identify factors that influence the sleep obtained. Flight crew operating flights between Everett, WA, USA and Asia had their sleep recorded polysomnographically for 1 night in a layover hotel and during a 7-h in-flight rest opportunity on flights averaging 15.7 h. Layover hotel and in-flight crew rest facilities onboard the Boeing 777-200ER aircraft. Twenty-one male flight crew (11 Captains, mean age 48 yr and 10 First Officers, mean age 35 yr). N/A. Sleep was recorded using actigraphy during the entire tour of duty, and polysomnographically in a layover hotel and during the flight. Mixed model analysis of covariance was used to determine the factors affecting in-flight sleep. In-flight sleep was less efficient (70% vs. 88%), with more nonrapid eye movement Stage 1/Stage 2 and more frequent awakenings per h (7.7/h vs. 4.6/h) than sleep in the layover hotel. In-flight sleep included very little slow wave sleep (median 0.5%). Less time was spent trying to sleep and less sleep was obtained when sleep opportunities occurred during the first half of the flight. Multivariate analyses suggest age is the most consistent factor affecting in-flight sleep duration and quality. This study confirms that even during long sleep opportunities, in-flight sleep is of poorer quality than sleep on the ground. With longer flight times, the quality and recuperative value of in-flight sleep is increasingly important for flight safety. Because the age limit for flight crew is being challenged, the consequences of age adversely affecting sleep quantity and quality need to be evaluated.

Solid phase extraction in combination with comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry for the detailed investigation of volatiles in South African red wines

NARCIS (Netherlands)

Weldegergis, B.T.; Crouch, A.M.; Górecki, T.; Villiers, de A.

2011-01-01

Comprehensive two-dimensional gas chromatography in combination with time-of-flight mass spectrometry (GC × GC–TOFMS) has been applied for the analysis of volatile compounds in three young South African red wines. In spite of the significant benefits offered by GC × GC–TOFMS for the separation and

Real-time flight conflict detection and release based on Multi-Agent system

Science.gov (United States)

Zhang, Yifan; Zhang, Ming; Yu, Jue

2018-01-01

This paper defines two-aircrafts, multi-aircrafts and fleet conflict mode, sets up space-time conflict reservation on the basis of safety interval and conflict warning time in three-dimension. Detect real-time flight conflicts combined with predicted flight trajectory of other aircrafts in the same airspace, and put forward rescue resolutions for the three modes respectively. When accorded with the flight conflict conditions, determine the conflict situation, and enter the corresponding conflict resolution procedures, so as to avoid the conflict independently, as well as ensure the flight safety of aimed aircraft. Lastly, the correctness of model is verified with numerical simulation comparison.

Diffractive scattering

CERN Document Server

De Wolf, E.A.

2002-01-01

We discuss basic concepts and properties of diffractive phenomena in soft hadron collisions and in deep-inelastic scattering at low Bjorken-x. The paper is not a review of the rapidly developing field but presents an attempt to show in simple terms the close inter-relationship between the dynamics of high-energy hadronic and deep-inelastic diffraction. Using the saturation model of Golec-Biernat and Wusthoff as an example, a simple explanation of geometrical scaling is presented. The relation between the QCD anomalous multiplicity dimension and the Pomeron intercept is discussed.

Diffractive Scattering

International Nuclear Information System (INIS)

Wolf, E.A. de

2002-01-01

We discuss basic concepts and properties of diffractive phenomena in soft hadron collisions and in deep-inelastic scattering at low Bjorken - x. The paper is not a review of the rapidly developing field but presents an attempt to show in simple terms the close inter-relationship between the dynamics of high-energy hadronic and deep-inelastic diffraction. Using the saturation model of Golec-Biernat and Wuesthoff as an example, a simple explanation of geometrical scaling is presented. The relation between the QCD anomalous multiplicity dimension and the Pomeron intercept is discussed. (author)

Refractive and diffractive scattering in the interstellar medium

International Nuclear Information System (INIS)

Cordes, J.M.; Pidwerbetsky, A.; Lovelace, R.V.E.

1986-01-01

Radio wave propagation through electron-density fluctuations in the ISM is studied. Observable propagation effects are explored using a one-dimensional thin-screen model for the turbulent medium. Diffraction caused by stochastic small-scale irregularities is combined with refraction from deterministic large-scale irregularities. Some of the effects are illustrated with numerical simulations of the wave propagation. Multiple imaging is considered, delineating the possible effects and discussing their extensions to two-dimensional screens and extended three-dimensional media. The case where refraction as well as diffraction is caused by a stochastic medium with a spectrum of a given form is considered. The magnitudes of observable effects is estimated for representative spectra that may be relevant to the ISM. The importance of the various effects for timing and scintillation observations of pulsars, VLBI observations of galactic and extragalactic radio sources, and for variability measurements of extragalactic sources is assessed. 47 references

Optic flow stabilizes flight in ruby-throated hummingbirds.

Science.gov (United States)

Ros, Ivo G; Biewener, Andrew A

2016-08-15

Flying birds rely on visual cues for retinal image stabilization by negating rotation-induced optic flow, the motion of the visual panorama across the retina, through corrective eye and head movements. In combination with vestibular and proprioceptive feedback, birds may also use visual cues to stabilize their body during flight. Here, we test whether artificially induced wide-field motion generated through projected visual patterns elicits maneuvers in body orientation and flight position, in addition to stabilizing vision. To test this hypothesis, we present hummingbirds flying freely within a 1.2 m cylindrical visual arena with a virtual surround rotated at different speeds about its vertical axis. The birds responded robustly to these visual perturbations by rotating their heads and bodies with the moving visual surround, and by adjusting their flight trajectories, following the surround. Thus, similar to insects, hummingbirds appear to use optic flow cues to control flight maneuvers as well as to stabilize their visual inputs. © 2016. Published by The Company of Biologists Ltd.

High-resolution 2-D Bragg diffraction reveal heterogeneous domain transformation behavior in a bulk relaxor ferroelectric

Energy Technology Data Exchange (ETDEWEB)

Pramanick, Abhijit, E-mail: apramani@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Kowloon (Hong Kong); Stoica, Alexandru D.; An, Ke [Chemical and Engineering Materials Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

2016-08-29

In-situ measurement of fine-structure of neutron Bragg diffraction peaks from a relaxor single-crystal using a time-of-flight instrument reveals highly heterogeneous mesoscale domain transformation behavior under applied electric fields. It is observed that only ∼25% of domains undergo reorientation or phase transition contributing to large average strains, while at least 40% remain invariant and exhibit microstrains. Such insights could be central for designing new relaxor materials with better performance and longevity. The current experimental technique can also be applied to resolve complex mesoscale phenomena in other functional materials.

Improving estimation of flight altitude in wildlife telemetry studies

Science.gov (United States)

Poessel, Sharon; Duerr, Adam E.; Hall, Jonathan C.; Braham, Melissa A.; Katzner, Todd

2018-01-01

Altitude measurements from wildlife tracking devices, combined with elevation data, are commonly used to estimate the flight altitude of volant animals. However, these data often include measurement error. Understanding this error may improve estimation of flight altitude and benefit applied ecology.There are a number of different approaches that have been used to address this measurement error. These include filtering based on GPS data, filtering based on behaviour of the study species, and use of state-space models to correct measurement error. The effectiveness of these approaches is highly variable.Recent studies have based inference of flight altitude on misunderstandings about avian natural history and technical or analytical tools. In this Commentary, we discuss these misunderstandings and suggest alternative strategies both to resolve some of these issues and to improve estimation of flight altitude. These strategies also can be applied to other measures derived from telemetry data.Synthesis and applications. Our Commentary is intended to clarify and improve upon some of the assumptions made when estimating flight altitude and, more broadly, when using GPS telemetry data. We also suggest best practices for identifying flight behaviour, addressing GPS error, and using flight altitudes to estimate collision risk with anthropogenic structures. Addressing the issues we describe would help improve estimates of flight altitude and advance understanding of the treatment of error in wildlife telemetry studies.

Flight to America

Directory of Open Access Journals (Sweden)

Güneli Gün

2011-01-01

Full Text Available Güneli Gün’s memoir piece truly combines the excitement of the young traveler with the humor of the mature narrator. Born in Izmir, Turkey, she breaks her engagement to a young but conservative Turkish architect and overcomes her father’s concerns to eventually study at Hollins College, Virginia. Addressing topics such as breaking out of a traditional society, being torn between the home country and the imagined new home, and finding comfort in the arts, “Flight to America” compellingly reflects Güneli Gün’s mastery as a storyteller.

Eclipse takeoff and flight

Science.gov (United States)

1998-01-01

This 25-second clip shows the QF-106 'Delta Dart' tethered to the USAF C-141A during takeoff and in flight. NASA Dryden Flight Research Center, Edwards, California, supported a Kelly Space and Technology, Inc. (KST)/U.S. Air Force project known as Eclipse, which demonstrated a reusable tow launch vehicle concept. The purpose of the project was to demonstrate a reusable tow launch vehicle concept that had been conceived and patented by KST. Kelly Space obtained a contract with the USAF Research Laboratory for the tow launch demonstration project under the Small Business Innovation Research (SBIR) program. The USAF SBIR contract included the modifications to turn the QF-106 into the Experimental Demonstrator #1 (EXD-01), and the C141A aircraft to incorporate the tow provisions to link the two aircraft, as well as conducting flight tests. The demonstration consisted of ground and flight tests. These tests included a Combined Systems Test of both airplanes joined by a tow rope, a towed taxi test, and six towed flights. The primary goal of the project was demonstrating the tow phase of the Eclipse concept using a scaled-down tow aircraft (C-141A) and a representative aerodynamically-shaped aircraft (QF-106A) as a launch vehicle. This was successfully accomplished. On December 20, 1997, NASA research pilot Mark Stucky flew a QF-106 on the first towed flight behind an Air Force C-141 in the joint Eclipse project with KST to demonstrate the reusable tow launch vehicle concept developed by KST. Kelly hoped to use the data from the tow tests to validate a tow-to-launch procedure for reusable space launch vehicles. Stucky flew six successful tow tests between December 1997 and February 6, 1998. On February 6, 1998, the sixth and final towed flight brought the project to a successful completion. Preliminary flight results determined that the handling qualities of the QF-106 on tow were very stable; actual flight measured values of tow rope tension were well within predictions

A pilot rating scale for evaluating failure transients in electronic flight control systems

Science.gov (United States)

Hindson, William S.; Schroeder, Jeffery A.; Eshow, Michelle M.

1990-01-01

A pilot rating scale was developed to describe the effects of transients in helicopter flight-control systems on safety-of-flight and on pilot recovery action. The scale was applied to the evaluation of hardovers that could potentially occur in the digital flight-control system being designed for a variable-stability UH-60A research helicopter. Tests were conducted in a large moving-base simulator and in flight. The results of the investigation were combined with existing airworthiness criteria to determine quantitative reliability design goals for the control system.

Helicopter flight simulation motion platform requirements

Science.gov (United States)

Schroeder, Jeffery Allyn

Flight simulators attempt to reproduce in-flight pilot-vehicle behavior on the ground. This reproduction is challenging for helicopter simulators, as the pilot is often inextricably dependent on external cues for pilot-vehicle stabilization. One important simulator cue is platform motion; however, its required fidelity is unknown. To determine the required motion fidelity, several unique experiments were performed. A large displacement motion platform was used that allowed pilots to fly tasks with matched motion and visual cues. Then, the platform motion was modified to give cues varying from full motion to no motion. Several key results were found. First, lateral and vertical translational platform cues had significant effects on fidelity. Their presence improved performance and reduced pilot workload. Second, yaw and roll rotational platform cues were not as important as the translational platform cues. In particular, the yaw rotational motion platform cue did not appear at all useful in improving performance or reducing workload. Third, when the lateral translational platform cue was combined with visual yaw rotational cues, pilots believed the platform was rotating when it was not. Thus, simulator systems can be made more efficient by proper combination of platform and visual cues. Fourth, motion fidelity specifications were revised that now provide simulator users with a better prediction of motion fidelity based upon the frequency responses of their motion control laws. Fifth, vertical platform motion affected pilot estimates of steady-state altitude during altitude repositionings. This refutes the view that pilots estimate altitude and altitude rate in simulation solely from visual cues. Finally, the combined results led to a general method for configuring helicopter motion systems and for developing simulator tasks that more likely represent actual flight. The overall results can serve as a guide to future simulator designers and to today's operators.

Top-down fabrication of vertical silicon nano-rings based on Poisson diffraction

International Nuclear Information System (INIS)

Ai Yujie; Huang Ru; Hao Zhihua; Wang Runsheng; Liu Changze; Fan Chunhui; Wang Yangyuan

2011-01-01

Vertical Si nano-rings with a uniform thickness of about 100 nm have been fabricated by conventional optical photolithography with a low cost based on Poisson diffraction. Moreover, the roughness of the Si nano-rings can be effectively reduced by sacrificial oxidation. In order to increase the density of the nano-rings, coaxial twin Si nano-rings have been fabricated by the Poisson diffraction method combined with the spacer technique. The thickness of both the inner and outer Si nano-rings is about 60 nm, and the gap between the twin nano-rings is about 100 nm.

Duality in diffraction dissociations

International Nuclear Information System (INIS)

Santoro, Alberto.

1977-01-01

Diffractive dissociations (aN→a*πN) are naturally explained and a model that accounts for the three-variable correlation (mass-transfer-Jackson angle correlation) is presented. This model takes into account the three possible exchanges: t (pion), u(a*) and s(a) channel exchanger. The physical consequences of the model are: a strong mass-slope correlation due to the zeros of the amplitude, a factorization of diffractive dissociations (factorization of the Pomeron), the possibility of extending this model to double diffractive dissociation and diffraction by nuclei. This model was applied to the NN→NπN reaction. Using the usual parameters of the Deck model, a comparison is made with experiments for all available distributions. the strong slope of the peak at 1400 MeV is naturally explained [fr

Flight Control of Biomimetic Air Vehicles Using Vibrational Control and Averaging

Science.gov (United States)

Tahmasian, Sevak; Woolsey, Craig A.

2017-08-01

A combination of vibrational inputs and state feedback is applied to control the flight of a biomimetic air vehicle. First, a control strategy is developed for longitudinal flight, using a quasi-steady aerodynamic model and neglecting wing inertial effects. Vertical and forward motion is controlled by modulating the wings' stroke and feather angles, respectively. Stabilizing control parameter values are determined using the time-averaged dynamic model. Simulations of a system resembling a hawkmoth show that the proposed controller can overcome modeling error associated with the wing inertia and small parameter uncertainties when following a prescribed trajectory. After introducing the approach through an application to longitudinal flight, the control strategy is extended to address flight in three-dimensional space.

In situ neutron diffraction study of grain-orientation-dependent phase transformation in 304L stainless steel at a cryogenic temperature

International Nuclear Information System (INIS)

Tao Kaixiang; Wall, James J.; Li, Hongqi; Brown, Donald W.; Vogel, Sven C.; Choo, Hahn

2006-01-01

In situ time-of-flight neutron diffraction was performed to investigate the martensitic phase transformation during quasistatic uniaxial compression testing of 304L stainless steel at 300 and 203 K. In situ neutron diffraction enabled the bulk measurement of intensity evolution for various hkl atomic planes during the austenite (fcc) to martensite (hcp and bcc) phase transformation. Based on the neutron diffraction patterns, the martensite phases were observed from the very beginning of the plastic deformation at 203 K. However, at 300 K, no newly formed martensite, except a small amount of preexisting hcp phase, was observed throughout the test. From the changes in the relative intensities of individual hkl atomic planes, the grain-orientation-dependent phase transformation was investigated. The preferred orientation of the newly formed martensite grains was also investigated for the sample deformed at 203 K using neutron diffraction. The results reveal the orientation relationships between the austenite and the newly formed martensites. The fcc grain family diffracting with (200) plane normal parallel to the loading axis is favored for the fcc to bcc transformation and the bcc (200) plane normals are primarily aligned along the loading direction. For the fcc to hcp transformation, the fcc grains with (111) plane normals at an angle in between about 10 deg. and 50 deg. to the loading direction are favored

Individual GaAs nanorods imaged by coherent X-ray diffraction

Energy Technology Data Exchange (ETDEWEB)

Pietsch, Ullrich; Biermanns, Andreas; Davydok, Anton [Universitaet Siegen (Germany); Paetzelt, Hendrik [Universitaet Leipzig (Germany); IOM Leipzig (Germany); Diaz, Ana; Metzger, Hartmut [ID01 Beamline, ESRF (France); Gottschalch, Volker [Universitaet Leipzig (Germany)

2010-07-01

Semiconductor nanorods are of particular interest for new semiconductor devices because the nanorod approach can be used to form heterostructures of materials with a large lattice mismatch and to define nanorod arrays with tailored inter-rod distance. However, all applications require objects with uniform physical properties based on uniform morphology. Complementary to electron microscopy techniques, destruction free X-ray diffraction techniques can be used to determine structural and morphological details. Using scanning X-ray diffraction microscopy with a spot size of 220 x 600 nm{sup 2} we were able to inspect individual GaAs nanorods grown by seed-free MOVPE through circular openings in a SiN{sub x} mask in a periodic array with 3 {mu}m spacing on GaAs[111]B. The focussed X-ray beam allows the determination of the strain state of individual rods and in combination with coherent diffraction imaging, we were able to characterize also morphological details. Rods grown at different positions in the array show significant differences in shape, size and strain state.

MAX: Development of a Laue diffraction lens for nuclear astrophysics

International Nuclear Information System (INIS)

Barriere, N.; Ballmoos, P. von; Skinner, G.; Smither, B.; Bastie, P.; Hinglais, E.; Abrosimov, N.; Alvarez, J.M.; Andersen, K.; Courtois, P.; Halloin, H.; Harris, M.; Isern, J.; Jean, P.; Knoedlseder, J.; Ubertini, P.; Vedrenne, G.; Weidenspointner, G.; Wunderer, C.

2006-01-01

The next generation of instrumentation for nuclear astrophysics will have to achieve an improvement in sensitivity by a factor of 10-100 over present technologies. With the focusing gamma-ray telescope MAX we take up this challenge and propose to combine the required sensitivity with high spectral and angular resolution, and the capability to measure the polarization of the photons. MAX is a space-borne crystal diffraction telescope, featuring a broad-band Laue lens optimized for the observation of compact sources in two wide energy bands of high astrophysical relevance. Gamma rays will be focused from the large collecting area of a crystal diffraction lens onto a very small detector volume. As a consequence, the signal to background ratio is greatly enhanced, leading to unprecedented sensitivities

The adsorption of methanol and water on SAPO-34: in situ and ex situ X-ray diffraction studies

DEFF Research Database (Denmark)

Wragg, David S.; Johnsen, Rune; Norby, Poul

2010-01-01

The adsorption of methanol on SAPO-34 has been studied using a combination of in situ synchrotron powder X-ray diffraction to follow the process and ex situ high resolution powder diffraction to determine the structure. The unit cell volume of SAPO-34 is found to expand by 0.5% during methanol ad...

Non-destructive bulk analysis of the Buggenum sword by neutron resonance capture analysis and neutron diffraction

International Nuclear Information System (INIS)

Postma, H.; Clarijs, M.; Borella, A.; Schillebeeckx, P.; Kamermans, H.

2010-01-01

Two neutron based techniques, neutron resonance capture analysis (NRCA) and time-of-flight neutron-diffraction (TOF-ND) have been used to determine the elemental composition and structure of a precious and very well preserved all-metal sword from the Bronze Age. This Buggenum sword was on loan from the National Museum of Antiquities (NMA) in Leiden (NL). NRCA and TOF-ND experiments have been carried out at a number of more or less identical positions of the sword. The tin-bronze ratio and the relative amounts of some minor elements (Sb, As, Ag, In) have been determined. The results of neutron diffraction measurements showed considerable tin-segregation, and clear indications of hardening on the edges of the blade. In addition, radiographs using Bremsstrahlung revealed the construction of the hilt-blade connection. The work was carried out at the EC Joint Research Centre IRMM in Geel (B) and at the ISIS facility of the Rutherford Appleton Laboratory (UK). (author)

Monitoring non-pseudomorphic epitaxial growth of spinel/perovskite oxide heterostructures by reflection high-energy electron diffraction

Energy Technology Data Exchange (ETDEWEB)

Schütz, P.; Pfaff, F.; Scheiderer, P.; Sing, M.; Claessen, R. [Physikalisches Institut and Röntgen Center for Complex Material Systems (RCCM), Universität Würzburg, Am Hubland, D-97074 Würzburg (Germany)

2015-02-09

Pulsed laser deposition of spinel γ-Al{sub 2}O{sub 3} thin films on bulk perovskite SrTiO{sub 3} is monitored by high-pressure reflection high-energy electron diffraction (RHEED). The heteroepitaxial combination of two materials with different crystal structures is found to be inherently accompanied by a strong intensity modulation of bulk diffraction patterns from inelastically scattered electrons, which impedes the observation of RHEED intensity oscillations. Avoiding such electron surface-wave resonance enhancement by de-tuning the RHEED geometry allows for the separate observation of the surface-diffracted specular RHEED signal and thus the real-time monitoring of sub-unit cell two-dimensional layer-by-layer growth. Since these challenges are essentially rooted in the difference between film and substrate crystal structure, our findings are of relevance for the growth of any heterostructure combining oxides with different crystal symmetry and may thus facilitate the search for novel oxide heterointerfaces.

Electro-optic diffraction grating tuned laser

International Nuclear Information System (INIS)

Hughes, R.S.

1975-01-01

An electro-optic diffraction grating tuned laser comprising a laser medium, output mirror, retro-reflective grating and an electro-optic diffraction grating beam deflector positioned between the laser medium and the reflective diffraction grating is described. An optional angle multiplier may be used between the electro-optic diffraction grating and the reflective grating. (auth)

Regge analysis of diffractive and leading baryon structure functions from deep inelastic scattering

International Nuclear Information System (INIS)

Batista, M.; Covolan, R.J.M.; Montanha, J.

2002-01-01

In this paper we present a combined analysis of the H1 data on leading baryon and diffractive structure functions from DIS, which are handled as two components of the same semi-inclusive process. The available structure function data are analyzed in a series of fits in which three main exchanges are taken into account: the Pomeron, Reggeon, and pion. For each of these contributions, Regge factorization of the correspondent structure function is assumed. By this procedure, we extract information about the interface between the diffractive, Pomeron-dominated, region and the leading proton spectrum, which is mostly ruled by secondary exchanges. One of the main results is that the relative Reggeon contribution to the semi-inclusive structure function is much smaller than the one obtained from an analysis of the diffractive structure function alone

Inelastic nucleon diffraction at high energy

International Nuclear Information System (INIS)

Goggi, G.

1975-01-01

Experiments carried out at ISR and at FNAL which have yielded a substantial amount of data on double diffraction processes, which were unambiguously indentified and measured and which provide new tools to study the dynamical properties shared by different classes of diffractive reactions are identified. In this review interest is focused on the experimental aspects of inclusive and exclusive results both on single and double diffraction and on the problems arising from their comparison. Problems covered include; inclusive and semi-inclusive diffraction, multiparticle inclusive studies, single-particle inclusive studies, resonance region, high mass region, exclusive single diffractive reactions, mass spectra, cross sections, t-dependence, decay angular properties, and double diffraction. (U.K.)

Structure determination of modulated structures by powder X-ray diffraction and electron diffraction

Czech Academy of Sciences Publication Activity Database

Zhou, Z.Y.; Palatinus, Lukáš; Sun, J.L.

2016-01-01

Roč. 3, č. 11 (2016), s. 1351-1362 ISSN 2052-1553 Institutional support: RVO:68378271 Keywords : electron diffraction * incommensurate structure * powder diffraction Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.036, year: 2016

The History and Promise of Combined Cycle Engines for Access to Space Applications

Science.gov (United States)

Clark, Casie

2010-01-01

For the summer of 2010, I have been working in the Aerodynamics and Propulsion Branch at NASA Dryden Flight Research Center studying combined-cycle engines, a high speed propulsion concept. Combined cycle engines integrate multiple propulsion systems into a single engine capable of running in multiple modes. These different modes allow the engine to be extremely versatile and efficient in varied flight conditions. The two most common types of combined cycle engines are Rocket-Based Combined Cycle (RBCC) and Turbine Based Combined Cycle (TBCC). The RBCC essentially combines a rocket and ramjet engine, while the TBCC integrates a turbojet and ramjet1. These two engines are able to switch between different propulsion modes to achieve maximum performance. Extensive conceptual and ground test studies of RBCC engines have been undertaken; however, an RBCC engine has never, to my knowledge, been demonstrated in flight. RBCC engines are of particular interest because they could potentially power a reusable launch vehicle (RLV) into space. The TBCC has been flight tested and shown to be effective at reaching supersonic speeds, most notably in the SR-71 Blackbird2.

Neutron Time-Of-Flight (n_TOF) experiment

CERN Multimedia

Brugger, M; Kaeppeler, F K; Jericha, E; Cortes rossell, G P; Riego perez, A; Baccomi, R; Laurent, B G; Griesmayer, E; Leeb, H; Dressler, M; Cano ott, D; Variale, V; Ventura, A; Carrillo de albornoz trillo, A; Andrzejewski, J J; Pavlik, A F; Kadi, Y; Zanni vlastou, R; Krticka, M; Kokkoris, M; Praena rodriguez, A J; Cortes giraldo, M A; Perkowski, J; Losito, R; Audouin, L; Weiss, C; Tagliente, G; Wallner, A; Woods, P J; Mengoni, A; Guerrero sanchez, C G; Tain enriquez, J L; Vlachoudis, V; Calviani, M; Junghans, A R; Reifarth, R; Mendoza cembranos, E; Quesada molina, J M; Babiano suarez, V; Schumann, M D; Tsinganis, A; Rauscher, T; Calvino tavares, F; Mingrone, F; Gonzalez romero, E M; Colonna, N; Negret, A L; Chiaveri, E; Milazzo, P M; De almeida carrapico, C A; Castelluccio, D M

The neutron time-of-flight facility n_TOF at CERN, Switzerland, operational since 2001, delivers neutrons using the Proton Synchrotron (PS) 20 GeV/c proton beam impinging on a lead spallation target. The facility combines a very high instantaneous neutron flux, an excellent time of flight resolution due to the distance between the experimental area and the production target (185 meters), a low intrinsic background and a wide range of neutron energies, from thermal to GeV neutrons. These characteristics provide a unique possibility to perform neutron-induced capture and fission cross-section measurements for applications in nuclear astrophysics and in nuclear reactor technology.

X-ray diffraction 2 - diffraction principles

International Nuclear Information System (INIS)

O'Connor, B.

1999-01-01

Full text: The computation of powder diffraction intensities is based on the principle that the powder pattern comprises the summation of the intensity contributions from each of the crystallites (or single crystals) in the material. Therefore, it is of value for powder diffractionists to appreciate the form of the expression for calculating single crystal diffraction pattern intensities. This knowledge is especially important for Rietveld analysis practitioners in terms of the (i) mathematics of the method and (ii) retrieving single crystal structure data from the literature. We consider the integrated intensity from a small single crystal being rotated at velocity ω through the Bragg angle θ for reflection (hkl).... I(hkl) = [l o /ω]. [e 4 /m 2 c 4 ]. [λ 3 δV F(hkl) 2 /υ 2 ].[(1+cos 2 2θ)/2sin2θ] where e, m and c are the usual fundamental constants; λ is the x-ray wavelength, δV is the crystallite volume; F(hkl) is the structure factor; υ is the unit cell volume; and (1+cos 2 θ)/2sin2θ] is the Lorentz-polarisation factor for an unpolarised incident beam. The expression does not include a contribution for extinction. The influence of factors λ, δV, F(hkl) and υ on the intensities should be appreciated by powder diffractionists, especially the structure factor, F(hkl), which is responsible for the fingerprint nature of diffraction patterns, such as the rise and fall of intensity from peak to peak. The structure factor expression represents the summation of the scattered waves from each of the j scattering centres (i e atoms) in the unit cell: F(hkl) Σ f j exp[2πi (h.x j +k.y i +l. z i )] T j . Symbol f is the scattering factor (representing the atom-type scattering efficiency); (x, y, z) are the fractional position coordinates of atom j within the unit cell; and T is the thermal vibration factor for the atom given by: T j = 8π 2 2 > sin 2 θ/λ 2 with 2 > being the mean-square vibration amplitude of the atom (assumed to be isotropic). The

Study of optical Laue diffraction

International Nuclear Information System (INIS)

Chakravarthy, Giridhar; Allam, Srinivasa Rao; Satyanarayana, S. V. M.; Sharan, Alok

2014-01-01

We present the study of the optical diffraction pattern of one and two-dimensional gratings with defects, designed using desktop pc and printed on OHP sheet using laser printer. Gratings so prepared, using novel low cost technique provides good visual aid in teaching. Diffraction pattern of the monochromatic light (632.8nm) from the grating so designed is similar to that of x-ray diffraction pattern of crystal lattice with point defects in one and two-dimensions. Here both optical and x-ray diffractions are Fraunhofer. The information about the crystalline lattice structure and the defect size can be known

Gluon radiation in diffractive electroproduction

International Nuclear Information System (INIS)

Buchmueller, W.; McDermott, M.F.; Hebecker, A.

1996-07-01

Order α s -correlations to the diffractive structure functions F L D and F 2 D at large Q 2 and small x are evaluated in the semiclassical approach, where the initial proton is treated as a classical colour field. The diffractive final state contains a fast gluon in addition to a quark-antiquark pair. Two of these partons may have large transverse momentum. Our calculations lead to an intuitive picture of deep-inelastic diffractive processes which is very similar to Bjorken's aligned-jet model. Both diffractive structure functions contain leading twist contributions from high-p perpendicular to jets. (orig.)

Study of optical Laue diffraction

Energy Technology Data Exchange (ETDEWEB)

Chakravarthy, Giridhar, E-mail: cgiridhar84@gmail.com, E-mail: aloksharan@email.com; Allam, Srinivasa Rao, E-mail: cgiridhar84@gmail.com, E-mail: aloksharan@email.com; Satyanarayana, S. V. M., E-mail: cgiridhar84@gmail.com, E-mail: aloksharan@email.com; Sharan, Alok, E-mail: cgiridhar84@gmail.com, E-mail: aloksharan@email.com [Department of Physics, Pondicherry University, Puducherry-605014 (India)

2014-10-15

We present the study of the optical diffraction pattern of one and two-dimensional gratings with defects, designed using desktop pc and printed on OHP sheet using laser printer. Gratings so prepared, using novel low cost technique provides good visual aid in teaching. Diffraction pattern of the monochromatic light (632.8nm) from the grating so designed is similar to that of x-ray diffraction pattern of crystal lattice with point defects in one and two-dimensions. Here both optical and x-ray diffractions are Fraunhofer. The information about the crystalline lattice structure and the defect size can be known.

Quantitative damage imaging using Lamb wave diffraction tomography

International Nuclear Information System (INIS)

Zhang Hai-Yan; Ruan Min; Zhu Wen-Fa; Chai Xiao-Dong

2016-01-01

In this paper, we investigate the diffraction tomography for quantitative imaging damages of partly through-thickness holes with various shapes in isotropic plates by using converted and non-converted scattered Lamb waves generated numerically. Finite element simulations are carried out to provide the scattered wave data. The validity of the finite element model is confirmed by the comparison of scattering directivity pattern (SDP) of circle blind hole damage between the finite element simulations and the analytical results. The imaging method is based on a theoretical relation between the one-dimensional (1D) Fourier transform of the scattered projection and two-dimensional (2D) spatial Fourier transform of the scattering object. A quantitative image of the damage is obtained by carrying out the 2D inverse Fourier transform of the scattering object. The proposed approach employs a circle transducer network containing forward and backward projections, which lead to so-called transmission mode (TMDT) and reflection mode diffraction tomography (RMDT), respectively. The reconstructed results of the two projections for a non-converted S0 scattered mode are investigated to illuminate the influence of the scattering field data. The results show that Lamb wave diffraction tomography using the combination of TMDT and RMDT improves the imaging effect compared with by using only the TMDT or RMDT. The scattered data of the converted A0 mode are also used to assess the performance of the diffraction tomography method. It is found that the circle and elliptical shaped damages can still be reasonably identified from the reconstructed images while the reconstructed results of other complex shaped damages like crisscross rectangles and racecourse are relatively poor. (special topics)

Characterization of Metalloproteins and Biomaterials by X-ray Absorption Spectroscopy and X-ray Diffraction

DEFF Research Database (Denmark)

Frankær, Christian Grundahl

This thesis presents thework on combining complementary X-rays techniques for studying the structures of proteins and other biomaterials, and consists of three different projects: (i) Characterization of protein powders with X-ray powder diffraction (XRPD). (ii) The combination of X-ray...... crystallography and X-ray absorption spectroscopy (XAS) applied to studying different hexameric insulin conformations. (iii) The structures of polymorphs of strontium ranelate and the distribution of strontium in bone tissue. A procedure for fast identification and verification of protein powders using XRPD...... was correction for disordered bulk-solvent, but also correction for background and optimization of unit cell parameters have to be taken into account. A sample holder was designed for collecting powder diffraction data on a standard laboratory X-ray powder diffractometer. The background was reduced by use...

Software for Managing Inventory of Flight Hardware

Science.gov (United States)

Salisbury, John; Savage, Scott; Thomas, Shirman

2003-01-01

The Flight Hardware Support Request System (FHSRS) is a computer program that relieves engineers at Marshall Space Flight Center (MSFC) of most of the non-engineering administrative burden of managing an inventory of flight hardware. The FHSRS can also be adapted to perform similar functions for other organizations. The FHSRS affords a combination of capabilities, including those formerly provided by three separate programs in purchasing, inventorying, and inspecting hardware. The FHSRS provides a Web-based interface with a server computer that supports a relational database of inventory; electronic routing of requests and approvals; and electronic documentation from initial request through implementation of quality criteria, acquisition, receipt, inspection, storage, and final issue of flight materials and components. The database lists both hardware acquired for current projects and residual hardware from previous projects. The increased visibility of residual flight components provided by the FHSRS has dramatically improved the re-utilization of materials in lieu of new procurements, resulting in a cost savings of over $1.7 million. The FHSRS includes subprograms for manipulating the data in the database, informing of the status of a request or an item of hardware, and searching the database on any physical or other technical characteristic of a component or material. The software structure forces normalization of the data to facilitate inquiries and searches for which users have entered mixed or inconsistent values.

Micromanipulation and pick-up system for X-Ray diffraction characterization of micrometer-sized single particles

International Nuclear Information System (INIS)

Takeichi, Y; Inami, N; Saito, K; Otori, H; Sagayama, R; Kumai, R; Ono, K; Ueno, T

2014-01-01

We describe a micromanipulation and pick-up system for preparing a micrometer-sized single particle for X-ray diffraction characterization. Combining a microgripper based on microelectromechanical systems, piezo-motor-driven linear stages, and a gamepad, the system provides precise and intuitive handling of the object. Single-crystal X-ray diffraction measurements of Sm-Fe-N permanent magnet were performed using this system. We also describe a method to distinguish crystallographically homogeneous particles found in powder-form samples.

Adaptive Backstepping Flight Control for Modern Fighter Aircraft

NARCIS (Netherlands)

Sonneveldt, L.

2010-01-01

The main goal of this thesis is to investigate the potential of the nonlinear adaptive backstepping control technique in combination with online model identification for the design of a reconfigurable flight control system for a modern fighter aircraft. Adaptive backstepping is a recursive,

Miracle Flights

Science.gov (United States)

... a Flight Get Involved Events Shop Miles Contact Miracle Flights Blog Giving Tuesday 800-359-1711 Thousands of children have been saved, but we still have miles to go. Request a Flight Click Here to Donate - Your ...

Diffraction attraction

International Nuclear Information System (INIS)

Anon.

1986-01-01

Elastic scattering – when colliding particles 'bounce' off each other like billiard balls – has always had a special interest for high energy physicists. While its simplicity makes for deep analogies with classical ideas like diffraction, its jbtle details also test our understanding of the intricate inner mechanisms which drive particle interactions. With a new stock of elastic scattering data now available thanks to experiments at the CERN proton-antiproton Collider, and with studies at higher energies imminent or planned, some seventy physicists gathered in the magnificent chateau at Blois, France, for a 'Workshop on Elastic and Diffractive Scattering at the Collider and Beyond'

Diffraction attraction

Energy Technology Data Exchange (ETDEWEB)

Anon.

1986-03-15

Elastic scattering – when colliding particles 'bounce' off each other like billiard balls – has always had a special interest for high energy physicists. While its simplicity makes for deep analogies with classical ideas like diffraction, its jbtle details also test our understanding of the intricate inner mechanisms which drive particle interactions. With a new stock of elastic scattering data now available thanks to experiments at the CERN proton-antiproton Collider, and with studies at higher energies imminent or planned, some seventy physicists gathered in the magnificent chateau at Blois, France, for a 'Workshop on Elastic and Diffractive Scattering at the Collider and Beyond'.

Influence of the crystal-surface unevenness on the angular spread of an x-ray diffracted beam

International Nuclear Information System (INIS)

Hrda, JaromIra; Potlovskiy, Kirill; Hrdy, JaromIr; Slechtova, Venceslava

2005-01-01

One of the factors influencing the focus size in diffractive-refractive optics is the quality of diffracting surface. If the surface is uneven, as it is when the silicon crystal surface is only etched, then the diffraction at each point of the surface is a combination of an asymmetric and inclined diffraction (general asymmetric diffraction). This somewhat deviates and spreads the diffracted beam. The integration over the surface hit by an incident beam gives the angular spread of the diffracted beam. It is shown theoretically that in some cases (highly asymmetric, highly inclined cut) the etched surface may create the spread of the diffracted beam such that it causes a significant broadening of the focus. In this case a mechanical-chemical polishing is necessary. This has been verified by us earlier in a preliminary experiment with synchrotron radiation. In this work the new experiment with the same crystals is performed using double crystal (+, -) arrangement and a laboratory x-ray source (CuKα radiation). We compared two samples; one of them is mechanically-chemically (MC) polished and thus the diffracting surface is almost perfect; the other is only etched. This experiment allows a better comparison of the result with the theory. The difference between the measured rocking curve widths for the etched and MC polished crystals (10'') roughly agrees with theory (7''), which supports the correctness of the theoretical approach

Observables of QCD diffraction

Science.gov (United States)

Mieskolainen, Mikael; Orava, Risto

2017-03-01

A new combinatorial vector space measurement model is introduced for soft QCD diffraction. The model independent mathematical construction resolves experimental complications; the theoretical framework of the approach includes the Good-Walker view of diffraction, Regge phenomenology together with AGK cutting rules and random fluctuations.

New structural studies of liquid crystal by reflectivity and resonant X-ray diffraction; Nouvelles etudes structurales de cristaux liquides par reflectivite et diffraction resonante des rayons X

Energy Technology Data Exchange (ETDEWEB)

Fernandes, P

2007-04-15

This memory presents three structural studies of smectic Liquid Crystals by reflectivity and resonant diffraction of X-rays. It is divided in five chapters. In the first a short introduction to Liquid Crystals is given. In particular, the smectic phases that are the object of this study are presented. The second chapter is consecrated to the X-ray experimental techniques that were used in this work. The three last chapters present the works on which this thesis can be divided. Chapter three demonstrates on free-standing films of MHPOBC (historic liquid crystal that possesses the antiferroelectric sub-phases) the possibility to extend the technique of resonant X-ray diffraction to liquid crystals without resonant element. In the fourth chapter the structure of the B{sub 2} liquid crystal phase of bent-core molecules (or banana molecules) is elucidated by using resonant X-ray diffraction combined with polarization analysis of the diffracted beam. A model of the polarization of the resonant beam diffracted by four different structures proposed for the B{sub 2} phase is developed in this chapter. In the fifth chapter a smectic binary mixture presenting a very original critical point of phase separation is studied by X-ray reflectivity and optical microscopy. A concentration gradient in the direction perpendicular to the plane of the film seems to be induced by the free-standing film geometry. The results of a simplified model of the system are compatible with this interpretation.

A neutron spectrometer based on the combination of time-of-flight and Larmor modulation

International Nuclear Information System (INIS)

Mulder, F.M.; Kreuger, R.; Grigoriev, S.V.; Kraan, W.H.; Rekveldt, M.Th.; Van Well, A.A.

1999-01-01

A study on the feasibility of neutron beam instrumentation that applies Larmor modulation for incoming, and time-of-flight for scattered wavelength determination (or vice versa) is currently under way at IRI. The instrument resulting from this combination can in principle measure quasi elastic and inelastic scattering with a flexible resolution and dynamic range. An important difference with current spectrometers is that there is no selection of neutron wavelengths for either the incoming beam (direct geometry) or scattered beam (inverted geometry). Therefore much of the available flux is used and there is no a priory selection of the energy transfer range and resolution. This instrument will be mainly applicable for quasi-elastic scattering and complex line shapes that are extended over a broad range in energy transfer. Line shapes can be measured directly in Fourier space, which is often advantageous. Due to signal to noise considerations, this instrument will be less suitable for the determination of weak, discrete energy transfer signals. A requirement for the Larmor modulator is that it can work with a white neutron beam. This can be realised for neutrons having a wavelength above ∼ 0.1 nm by use of 'adiabatic resonance π flippers'. This type of instrument may be applied at the future ESS pulsed neutron source in order to complement current spectrometers. (author)

The analysis of powder diffraction data

International Nuclear Information System (INIS)

David, W.I.F.; Harrison, W.T.A.

1986-01-01

The paper reviews neutron powder diffraction data analysis, with emphasis on the structural aspects of powder diffraction and the future possibilities afforded by the latest generation of very high resolution neutron and x-ray powder diffractometers. Traditional x-ray powder diffraction techniques are outlined. Structural studies by powder diffraction are discussed with respect to the Rietveld method, and a case study in the Rietveld refinement method and developments of the Rietveld method are described. Finally studies using high resolution powder diffraction at the Spallation Neutron Source, ISIS at the Rutherford Appleton Laboratory are summarized. (U.K.)

Diffraction by m-bonacci gratings

International Nuclear Information System (INIS)

Monsoriu, Juan A; Giménez, Marcos H; Furlan, Walter D; Barreiro, Juan C; Saavedra, Genaro

2015-01-01

We present a simple diffraction experiment with m-bonacci gratings as a new interesting generalization of the Fibonacci ones. Diffraction by these non-conventional structures is proposed as a motivational strategy to introduce students to basic research activities. The Fraunhofer diffraction patterns are obtained with the standard equipment present in most undergraduate physics labs and are compared with those obtained with regular periodic gratings. We show that m-bonacci gratings produce discrete Fraunhofer patterns characterized by a set of diffraction peaks which positions are related to the concept of a generalized golden mean. A very good agreement is obtained between experimental and numerical results and the students’ feedback is discussed. (paper)

Atomic-layer-resolved analysis of surface magnetism by diffraction spectroscopy

International Nuclear Information System (INIS)

Matsui, Fumihiko; Matsushita, Tomohiro; Daimon, Hiroshi

2010-01-01

X-ray absorption near edge structure (XANES) and X-ray magnetic circular dichroism (XMCD) measurements by Auger-electron-yield detection are powerful analysis tools for the electronic and magnetic structures of surfaces, but all the information from atoms within the electron mean-free-path range is summed into the obtained spectrum. In order to investigate the electronic and magnetic structures of each atomic layer at subsurface, we have proposed a new method, diffraction spectroscopy, which is the combination of X-ray absorption spectroscopy and Auger electron diffraction (AED). From a series of measured thickness dependent AED patterns, we deduced a set of atomic-layer-specific AED patterns arithmetically. Based on these AED patterns, we succeeded in disentangling obtained XANES and XMCD spectra into those from different atomic layers.

Combined near- and far-field high-energy diffraction microscopy dataset for Ti-7Al tensile specimen elastically loaded in situ

Energy Technology Data Exchange (ETDEWEB)

Turner, Todd J.; Shade, Paul A.; Bernier, Joel V.; Li, Shiu Fai; Schuren, Jay C.; Lind, Jonathan; Lienert, Ulrich; Kenesei, Peter; Suter, Robert M.; Blank, Basil; Almer, Jonathan

2016-03-18

High-energy diffraction microscopy (HEDM) constitutes a suite of combined X-ray characterization methods, which hold the unique advantage of illuminating the microstructure and micromechanical state of a material during concurrent in situ mechanical deformation. The data generated from HEDM experiments provides a heretofore unrealized opportunity to validate meso-scale modeling techniques, such as crystal plasticity finite element modeling (CPFEM), by explicitly testing the accuracy of these models at the length scales where the models predict their response. Combining HEDM methods with in situ loading under known and controlled boundary conditions represents a significant challenge, inspiring the recent development of a new high-precision rotation and axial motion system for simultaneously rotating and axially loading a sample. In this paper, we describe the initial HEDM dataset collected using this hardware on an alpha-titanium alloy (Ti-7Al) under in situ tensile deformation at the Advanced Photon Source, Argonne National Laboratory. We present both near-field HEDM data that maps out the grain morphology and intragranular crystallographic orientations and far-field HEDM data that provides the grain centroid, grain average crystallographic orientation, and grain average elastic strain tensor for each grain. Finally, we provide a finite element mesh that can be utilized to simulate deformation in the volume of this Ti-7Al specimen. The dataset supporting this article is available in the National Institute of Standards and Technology (NIST) repository (http://hdl.handle.net/11256/599).

Unified Nonlinear Flight Dynamics and Aeroelastic Simulator Tool, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — ZONA Technology, Inc. (ZONA) proposes a R&D effort to develop a Unified Nonlinear Flight Dynamics and Aeroelastic Simulator (UNFDAS) Tool that will combine...

Performance evaluation and design of flight vehicle control systems

CERN Document Server

Falangas, Eric T

2015-01-01

This book will help students, control engineers and flight dynamics analysts to model and conduct sophisticated and systemic analyses of early flight vehicle designs controlled with multiple types of effectors and to design and evaluate new vehicle concepts in terms of satisfying mission and performance goals. Performance Evaluation and Design of Flight Vehicle Control Systems begins by creating a dynamic model of a generic flight vehicle that includes a range of elements from airplanes and launch vehicles to re-entry vehicles and spacecraft. The models may include dynamic effects dealing with structural flexibility, as well as dynamic coupling between structures and actuators, propellant sloshing, and aeroelasticity, and they are typically used for control analysis and design. The book shows how to efficiently combine different types of effectors together, such as aero-surfaces, TVC, throttling engines and RCS, to operate as a system by developing a mixing logic atrix. Methods of trimming a vehicle controll...

Comparative study of macrotexture analysis using X-ray diffraction and electron backscattered diffraction techniques

International Nuclear Information System (INIS)

Serna, Marilene Morelli

2002-01-01

The macrotexture is one of the main characteristics in metallic materials, which the physical properties depend on the crystallographic direction. The analysis of the macrotexture to middles of the decade of 80 was just accomplished by the techniques of Xray diffraction and neutrons diffraction. The possibility of the analysis of the macrotexture using, the technique of electron backscattering diffraction in the scanning electronic microscope, that allowed to correlate the measure of the orientation with its location in the micro structure, was a very welcome tool in the area of engineering of materials. In this work it was studied the theoretical aspects of the two techniques and it was used of both techniques for the analysis of the macrotexture of aluminum sheets 1050 and 3003 with intensity, measured through the texture index 'J', from 2.00 to 5.00. The results obtained by the two techniques were shown reasonably similar, being considered that the statistics of the data obtained by the technique of electron backscatter diffraction is much inferior to the obtained by the X-ray diffraction. (author)

X-ray diffraction analysis of InAs nanowires

International Nuclear Information System (INIS)

Davydok, Anton

2013-01-01

Semiconductor nanowires have attracted great interest as building blocks for future electronic and optoelectronic devices. The variability of the growth process opens the opportunity to control and combine the various properties tailoring for specific application. It was shown that the electrical and optical characteristics of the nanowires are strongly connected with their structure. Despite intensive research in this field, the growth process is still not fully understood. In particular, extensive real structure investigations are required. Most of the reports dedicated on the structural researches are based on the results of scanning electron microscopy (SEM) or transmission electron microscopy (TEM). SEM provides an image of the surface with nanostructures and is mainly used to describe the morphology of the sample, but it does not bring information about the internal structure, phase composition and defect structure. At the same time, the internal structure can be examined by TEM down to atomic scale. TEM image of good quality are very expensive due to the efforts in sample preparation and in localisation of a single object. All these aspects make the statistical structural analysis difficult. In the present work, X-ray diffraction analysis has been applied for structural investigation of InAs nanowires grown by different techniques. Using various X-ray diffraction geometries, the nanowire systems were investigated in terms of the lattice parameters, phase composition, strains and displacement fields and stacking defects. In particular, realizing grazing incidence diffraction and controlling the penetration depth of X-ray beam, we characterized sample series grown by Au-assisted metal organic phase epitaxy on GaAs [111]B substrate with different growth time. According to the results of SEM and X-ray investigations, a model of the growth process has been proposed. A more detailed analysis was performed on InAs nanowires grown by molecular beam epitaxy (MBE) on

Diffractive Production of Jets and Weak Bosons, and Tests of Hard-Scattering Factorization

CERN Document Server

Alvero, L; Terrón, J; Whitmore, J; Alvero, Lyndon; Collins, John C.; Terron, Juan; Whitmore, Jim

1999-01-01

We extract diffractive parton densities from diffractive, deep inelastic (DIS) ep data from the ZEUS experiment. Then we use these fits to predict the diffractive production of jets and of W's and Z's in p\\bar p collisions at the Tevatron. Although the DIS data require a hard quark density in the pomeron, we find fairly low rates for the Tevatron processes (a few percent of the inclusive cross section). This results from the combined effects of Q^{2} evolution and of a normalization of the parton densities to the data. The calculated rates for W production are generally consistent with the preliminary data from the Tevatron. However, the jet data from CDF with a ``Roman pot'' trigger are substantially lower than the results of our calculations; if confirmed, this would signal a breakdown of hard-scattering factorization.

Takagi-Taupin description of x-ray dynamical diffraction from diffractive optics with large numerical aperture

International Nuclear Information System (INIS)

Yan Hanfei; Maser, Joerg; Macrander, Albert; Shen Qun; Vogt, Stefan; Stephenson, G. Brian; Kang, Hyon Chol

2007-01-01

We present a formalism of x-ray dynamical diffraction from volume diffractive optics with large numerical aperture and high aspect ratio, in an analogy to the Takagi-Taupin equations [Acta Crystallogr. 15, 1311 (1962); Bull. Soc. Fr. Mineral. Crystallogr. 87, 469 (1964)] for strained single crystals. We derive a set of basic equations for dynamical diffraction from volume diffractive optics, which enable us to study the focusing property of these optics with various grating profiles. We study volume diffractive optics that satisfy the Bragg condition to various degrees, namely, flat, tilted, and wedged geometries, and derive the curved geometries required for ultimate focusing. We show that the curved geometries satisfy both the Bragg condition everywhere and phase requirement for point focusing and effectively focus hard x rays to a scale close to the wavelength. Our calculations were made for an x-ray wavelength of 0.064 nm (19.5 keV)

X-ray Laue diffraction with allowance for second derivatives of amplitudes in dynamical diffraction equations

International Nuclear Information System (INIS)

Balyan, M.K.

2014-01-01

Asymmetrical Laue diffraction in a perfect crystal with a plane entrance surface is considered. The second derivatives of amplitudes in the direction, perpendicular to diffraction plane in the dynamical diffraction equations are taken into account. Using the corresponding Green function a general form for the amplitude of diffracted wave in the crystal is derived. The sizes of the source in both directions as well as the source of crystal distance and non-monochromaticity of the radiation incident on the crystal are taken into account. On the basis of obtained expression the coherent properties of the field depending on the sizes of the source and on the width of the spectrum of the incident radiation are analyzed. Taking into account the second derivatives of amplitudes with respect to the direction, perpendicular to the diffraction plane, the time dependent propagation equations for an X-ray pulse in a perfect crystal are given

IR sensitivity enhancement of CMOS Image Sensor with diffractive light trapping pixels.

Science.gov (United States)

Yokogawa, Sozo; Oshiyama, Itaru; Ikeda, Harumi; Ebiko, Yoshiki; Hirano, Tomoyuki; Saito, Suguru; Oinoue, Takashi; Hagimoto, Yoshiya; Iwamoto, Hayato

2017-06-19

We report on the IR sensitivity enhancement of back-illuminated CMOS Image Sensor (BI-CIS) with 2-dimensional diffractive inverted pyramid array structure (IPA) on crystalline silicon (c-Si) and deep trench isolation (DTI). FDTD simulations of semi-infinite thick c-Si having 2D IPAs on its surface whose pitches over 400 nm shows more than 30% improvement of light absorption at λ = 850 nm and the maximum enhancement of 43% with the 540 nm pitch at the wavelength is confirmed. A prototype BI-CIS sample with pixel size of 1.2 μm square containing 400 nm pitch IPAs shows 80% sensitivity enhancement at λ = 850 nm compared to the reference sample with flat surface. This is due to diffraction with the IPA and total reflection at the pixel boundary. The NIR images taken by the demo camera equip with a C-mount lens show 75% sensitivity enhancement in the λ = 700-1200 nm wavelength range with negligible spatial resolution degradation. Light trapping CIS pixel technology promises to improve NIR sensitivity and appears to be applicable to many different image sensor applications including security camera, personal authentication, and range finding Time-of-Flight camera with IR illuminations.

A hybrid method combining the Time-Domain Method of Moments, the Time-Domain Uniform Theory of Diffraction and the FDTD

Directory of Open Access Journals (Sweden)

A. Becker

2007-06-01

Full Text Available In this paper a hybrid method combining the Time-Domain Method of Moments (TD-MoM, the Time-Domain Uniform Theory of Diffraction (TD-UTD and the Finite-Difference Time-Domain Method (FDTD is presented. When applying this new hybrid method, thin-wire antennas are modeled with the TD-MoM, inhomogeneous bodies are modelled with the FDTD and large perfectly conducting plates are modelled with the TD-UTD. All inhomogeneous bodies are enclosed in a so-called FDTD-volume and the thin-wire antennas can be embedded into this volume or can lie outside. The latter avoids the simulation of white space between antennas and inhomogeneous bodies. If the antennas are positioned into the FDTD-volume, their discretization does not need to agree with the grid of the FDTD. By using the TD-UTD large perfectly conducting plates can be considered efficiently in the solution-procedure. Thus this hybrid method allows time-domain simulations of problems including very different classes of objects, applying the respective most appropriate numerical techniques to every object.

CMS results on hard diffraction

CERN Document Server

INSPIRE-00107098

2013-01-01

In these proceedings we present CMS results on hard diffraction. Diffractive dijet production in pp collisions at $\\sqrt{s}$=7 TeV is discussed. The cross section for dijet production is presented as a function of $\\tilde{\\xi}$, representing the fractional momentum loss of the scattered proton in single-diffractive events. The observation of W and Z boson production in events with a large pseudo-rapidity gap is also presented.

International Centre for Diffraction Data (ICDD)

International Nuclear Information System (INIS)

Hubbard, C.R.; O'Connor, B.H.

2002-01-01

Full text: The ICDD is a not-for-profit organisation comprising approximately 300 of the world's leading x-ray scientists. It is dedicated to collecting, editing, publishing and distributing powder diffraction data for the identification of crystalline materials. The membership of the ICDD consists of worldwide representation from academe, government and industry. It is our mission to continue as the world centre for quality x-ray powder diffraction data to meet the needs of the technical community. Through the combined efforts of the members and its staff of 40 at ICDD Headquarters, the organisation serves the x-ray analysis community (i) by producing the ICDD Powder Diffraction File (PDF) and other data base products for materials characterisation; (ii) through x-ray analysis education programs and conference management (including the Denver X-ray Conference); and (iii) through philanthropic initiatives such as scholarship support for postgraduate students working in the field. The current Release 2001 of the PDF (PDF-2) contains 87,500 measured patterns and 49,000 patterns calculated from the ICSD database. The number of PDF patterns in this latest release has increased by approximately 3,000, including some 2,500 measured patterns. The quality of the database is being continuously improved through the organisation's Grant-in-Aid program whereby diffractionists around the world contribute to the measurement of patterns for new materials and to the improvement of existing PDF data. The organisation is devoting much attention to the needs of the bioscience community. The database will soon feature a much-expanded set of patterns for organic, polymer, pharmaceutical and biomaterials. The ICDD is about to release a relational database (RDB) version of the PDF (PDF-4) which will give users a very sophisticated tool for data mining. The PDF-4 will provide a quantum leap in data mining techniques, and will soon lead to the PDF being cross-linked to other diffraction

Analyze of phase's mechanical behaviour of a multiphase polycrystalline alloy by X-ray and neutron diffraction; Analyse du comportement mecanique des constituants d'un alliage polycristallin multiphase par diffraction des rayons X et neutronique

Energy Technology Data Exchange (ETDEWEB)

Dakhlaoui, R

2006-12-15

The aim of this work is to propose a methodology using diffraction methods and theoretical approaches of self-consistent modeling in order to analyze and better understand the mechanical behavior of each phase of hot-rolled duplex stainless steel. The purpose of the experimental study is to characterize the local mechanical behavior of phases under uniaxial loading. X-ray and neutron diffraction which enable to measure strains in each phase separately were used in this aim. Austenitic and ferritic phase stresses are determined by X-ray diffraction during tensile tests. Evolution of the elastic strains in each phase was measured by neutron diffraction using 'time-of-flight' method during tensile and compression tests. Elastic constants were given using the self-consistent model for a purely elastic deformation. To reproduce the mechanical behaviour of the studied material, self-consistent polycrystalline micro-mechanical model for elastoplastic deformation has been adapted and confronted to experimental results. Crystallographic texture and initial residual stresses were considered in this analysis. Critical shear stresses and hardening parameters of each phase of the studied duplex steel have been identified. Results of this study showed that the austenitic phase represents the softest and the most hardenable phase. Taking into account in calculations the initial residual stresses in the non deformed sample leads to the conclusion that the initial stresses modify considerably the values of phase's yield stresses. Good agreement has been noted comparing results obtained by XRD to those obtained by neutron diffraction. The problem of relaxation of normal stresses in the analysed layer by X-rays was analysed and discussed. Using XRD and self-consistent modelling, the effect of the chemical composition of the duplex stainless steel and the influence of ageing at 400 C degrees for 1000 h on the mechanical behaviour of austenitic and ferritic phases have

Powder diffraction

Energy Technology Data Exchange (ETDEWEB)

Hart, M.

1995-12-31

the importance of x-ray powder diffraction as an analytical tool for phase identification of materials was first pointed out by Debye and Scherrer in Germany and, quite independently, by Hull in the US. Three distinct periods of evolution lead to ubiquitous application in many fields of science and technology. In the first period, until the mid-1940`s, applications were and developed covering broad categories of materials including inorganic materials, minerals, ceramics, metals, alloys, organic materials and polymers. During this formative period, the concept of quantitative phase analysis was demonstrated. In the second period there followed the blossoming of technology and commercial instruments became widely used. The history is well summarized by Parrish and by Langford and Loueer. By 1980 there were probably 10,000 powder diffractometers in routine use, making it the most widely used of all x-ray crystallographic instruments. In the third, present, period data bases became firmly established and sophisticated pattern fitting and recognition software made many aspects of powder diffraction analysis routine. High resolution, tunable powder diffractometers were developed at sources of synchrotron radiation. The tunability of the spectrum made it possible to exploit all the subtleties of x-ray spectroscopy in diffraction experiments.

Powder diffraction

International Nuclear Information System (INIS)

Hart, M.

1995-01-01

The importance of x-ray powder diffraction as an analytical tool for phase identification of materials was first pointed out by Debye and Scherrer in Germany and, quite independently, by Hull in the US. Three distinct periods of evolution lead to ubiquitous application in many fields of science and technology. In the first period, until the mid-1940's, applications were and developed covering broad categories of materials including inorganic materials, minerals, ceramics, metals, alloys, organic materials and polymers. During this formative period, the concept of quantitative phase analysis was demonstrated. In the second period there followed the blossoming of technology and commercial instruments became widely used. The history is well summarized by Parrish and by Langford and Loueer. By 1980 there were probably 10,000 powder diffractometers in routine use, making it the most widely used of all x-ray crystallographic instruments. In the third, present, period data bases became firmly established and sophisticated pattern fitting and recognition software made many aspects of powder diffraction analysis routine. High resolution, tunable powder diffractometers were developed at sources of synchrotron radiation. The tunability of the spectrum made it possible to exploit all the subtleties of x-ray spectroscopy in diffraction experiments

Transient immune impairment after a simulated long-haul flight.

Science.gov (United States)

Wilder-Smith, Annelies; Mustafa, Fatima B; Peng, Chung Mien; Earnest, Arul; Koh, David; Lin, Gen; Hossain, Iqbal; MacAry, Paul A

2012-04-01

Almost 2 billion people travel aboard commercial airlines every year, with about 20% developing symptoms of the common cold within 1 wk after air travel. We hypothesize that hypobaric hypoxic conditions associated with air travel may contribute to immune impairment. We studied the effects of hypobaric hypoxic conditions during a simulated flight at 8000 ft (2438 m) cruising altitude on immune and stress markers in 52 healthy volunteers (mean age 31) before and on days 1, 4, and 7 after the flight. We did a cohort study using a generalized estimating equation to examine the differences in the repeated measures. Our findings show that the hypobaric hypoxic conditions of a 10-h overnight simulation flight are not associated with severe immune impairment or abnormal IgA or cortisol levels, but with transient impairment in some parameters: we observed a transient decrease in lymphocyte proliferative responses combined with an upregulation in CD69 and CD14 cells and a decrease in HLA-DR in the immediate days following the simulated flight that normalized by day 7 in most instances. These transient immune changes may contribute to an increased susceptibility to respiratory infections commonly seen after long-haul flights.

Measurement of inelastic, single- and double-diffraction cross sections in proton-proton collisions at the LHC with ALICE

CERN Document Server

Abelev, Betty; Adamova, Dagmar; Adare, Andrew Marshall; Aggarwal, Madan; Aglieri Rinella, Gianluca; Agocs, Andras Gabor; Agostinelli, Andrea; Aguilar Salazar, Saul; Ahammed, Zubayer; Ahmad, Nazeer; Ahmad, Arshad; Ahn, Sul-Ah; Ahn, Sang Un; Akindinov, Alexander; Aleksandrov, Dmitry; Alessandro, Bruno; Alfaro Molina, Jose Ruben; Alici, Andrea; Alkin, Anton; Almaraz Avina, Erick Jonathan; Alme, Johan; Alt, Torsten; Altini, Valerio; Altinpinar, Sedat; Altsybeev, Igor; Andrei, Cristian; Andronic, Anton; Anguelov, Venelin; Anielski, Jonas; Anson, Christopher Daniel; Anticic, Tome; Antinori, Federico; Antonioli, Pietro; Aphecetche, Laurent Bernard; Appelshauser, Harald; Arbor, Nicolas; Arcelli, Silvia; Arend, Andreas; Armesto, Nestor; Arnaldi, Roberta; Aronsson, Tomas Robert; Arsene, Ionut Cristian; Arslandok, Mesut; Asryan, Andzhey; Augustinus, Andre; Averbeck, Ralf Peter; Awes, Terry; Aysto, Juha Heikki; Azmi, Mohd Danish; Bach, Matthias Jakob; Badala, Angela; Baek, Yong Wook; Bailhache, Raphaelle Marie; Bala, Renu; Baldini Ferroli, Rinaldo; Baldisseri, Alberto; Baldit, Alain; Baltasar Dos Santos Pedrosa, Fernando; Ban, Jaroslav; Baral, Rama Chandra; Barbera, Roberto; Barile, Francesco; Barnafoldi, Gergely Gabor; Barnby, Lee Stuart; Barret, Valerie; Bartke, Jerzy Gustaw; Basile, Maurizio; Bastid, Nicole; Basu, Sumit; Bathen, Bastian; Batigne, Guillaume; Batyunya, Boris; Baumann, Christoph Heinrich; Bearden, Ian Gardner; Beck, Hans; Behera, Nirbhay Kumar; Belikov, Iouri; Bellini, Francesca; Bellwied, Rene; Belmont-Moreno, Ernesto; Bencedi, Gyula; Beole, Stefania; Berceanu, Ionela; Bercuci, Alexandru; Berdnikov, Yaroslav; Berenyi, Daniel; Bergognon, Anais Annick Erica; Berzano, Dario; Betev, Latchezar; Bhasin, Anju; Bhati, Ashok Kumar; Bhom, Jihyun; Bianchi, Livio; Bianchi, Nicola; Bianchin, Chiara; Bielcik, Jaroslav; Bielcikova, Jana; Bilandzic, Ante; Bjelogrlic, Sandro; Blanco, F; Blanco, Francesco; Blau, Dmitry; Blume, Christoph; Boccioli, Marco; Bock, Nicolas; Boettger, Stefan; Bogdanov, Alexey; Boggild, Hans; Bogolyubsky, Mikhail; Boldizsar, Laszlo; Bombara, Marek; Book, Julian; Borel, Herve; Borissov, Alexander; Bose, Suvendu Nath; Bossu, Francesco; Botje, Michiel; Botta, Elena; Boyer, Bruno Alexandre; Braidot, Ermes; Braun-Munzinger, Peter; Bregant, Marco; Breitner, Timo Gunther; Browning, Tyler Allen; Broz, Michal; Brun, Rene; Bruna, Elena; Bruno, Giuseppe Eugenio; Budnikov, Dmitry; Buesching, Henner; Bufalino, Stefania; Busch, Oliver; Buthelezi, Edith Zinhle; Caballero Orduna, Diego; Caffarri, Davide; Cai, Xu; Caines, Helen Louise; Calvo Villar, Ernesto; Camerini, Paolo; Canoa Roman, Veronica; Cara Romeo, Giovanni; Carena, Wisla; Carena, Francesco; Carlin Filho, Nelson; Carminati, Federico; Casanova Diaz, Amaya Ofelia; Castillo Castellanos, Javier Ernesto; Castillo Hernandez, Juan Francisco; Casula, Ester Anna Rita; Catanescu, Vasile; Cavicchioli, Costanza; Ceballos Sanchez, Cesar; Cepila, Jan; Cerello, Piergiorgio; Chang, Beomsu; Chapeland, Sylvain; Charvet, Jean-Luc Fernand; Chattopadhyay, Subhasis; Chattopadhyay, Sukalyan; Chawla, Isha; Cherney, Michael Gerard; Cheshkov, Cvetan; Cheynis, Brigitte; Chibante Barroso, Vasco Miguel; Chinellato, David; Chochula, Peter; Chojnacki, Marek; Choudhury, Subikash; Christakoglou, Panagiotis; Christensen, Christian Holm; Christiansen, Peter; Chujo, Tatsuya; Chung, Suh-Urk; Cicalo, Corrado; Cifarelli, Luisa; Cindolo, Federico; Cleymans, Jean Willy Andre; Coccetti, Fabrizio; Colamaria, Fabio; Colella, Domenico; Conesa Balbastre, Gustavo; Conesa del Valle, Zaida; Contin, Giacomo; Contreras, Jesus Guillermo; Cormier, Thomas Michael; Corrales Morales, Yasser; Cortese, Pietro; Cortes Maldonado, Ismael; Cosentino, Mauro Rogerio; Costa, Filippo; Cotallo, Manuel Enrique; Crescio, Elisabetta; Crochet, Philippe; Cruz Alaniz, Emilia; Cuautle, Eleazar; Cunqueiro, Leticia; Dainese, Andrea; Dalsgaard, Hans Hjersing; Danu, Andrea; Das, Kushal; Das, Indranil; Das, Debasish; Dash, Sadhana; Dash, Ajay Kumar; De, Sudipan; de Barros, Gabriel; De Caro, Annalisa; de Cataldo, Giacinto; de Cuveland, Jan; De Falco, Alessandro; De Gruttola, Daniele; Delagrange, Hugues; Deloff, Andrzej; De Marco, Nora; Denes, Ervin; De Pasquale, Salvatore; Deppman, Airton; D'Erasmo, Ginevra; de Rooij, Raoul Stefan; Diaz Corchero, Miguel Angel; Di Bari, Domenico; Dietel, Thomas; Di Giglio, Carmelo; Di Liberto, Sergio; Di Mauro, Antonio; Di Nezza, Pasquale; Divia, Roberto; Djuvsland, Oeystein; Dobrin, Alexandru Florin; Dobrowolski, Tadeusz Antoni; Dominguez, Isabel; Donigus, Benjamin; Dordic, Olja; Driga, Olga; Dubey, Anand Kumar; Dubla, Andrea; Ducroux, Laurent; Dupieux, Pascal; Dutta Majumdar, AK; Dutta Majumdar, Mihir Ranjan; Elia, Domenico; Emschermann, David Philip; Engel, Heiko; Erazmus, Barbara; Erdal, Hege Austrheim; Espagnon, Bruno; Estienne, Magali Danielle; Esumi, Shinichi; Evans, David; Eyyubova, Gyulnara; Fabris, Daniela; Faivre, Julien; Falchieri, Davide; Fantoni, Alessandra; Fasel, Markus; Fearick, Roger Worsley; Fehlker, Dominik; Feldkamp, Linus; Felea, Daniel; Fenton-Olsen, Bo; Feofilov, Grigory; Fernandez Tellez, Arturo; Ferretti, Alessandro; Ferretti, Roberta; Festanti, Andrea; Figiel, Jan; Figueredo, Marcel; Filchagin, Sergey; Finogeev, Dmitry; Fionda, Fiorella; Fiore, Enrichetta Maria; Floris, Michele; Foertsch, Siegfried Valentin; Foka, Panagiota; Fokin, Sergey; Fragiacomo, Enrico; Francescon, Andrea; Frankenfeld, Ulrich Michael; Fuchs, Ulrich; Furget, Christophe; Fusco Girard, Mario; Gaardhoje, Jens Joergen; Gagliardi, Martino; Gago, Alberto; Gallio, Mauro; Gangadharan, Dhevan Raja; Ganoti, Paraskevi; Garabatos, Jose; Garcia-Solis, Edmundo; Garishvili, Irakli; Gerhard, Jochen; Germain, Marie; Geuna, Claudio; Gheata, Mihaela; Gheata, Andrei George; Ghidini, Bruno; Ghosh, Premomoy; Gianotti, Paola; Girard, Martin Robert; Giubellino, Paolo; Gladysz-Dziadus, Ewa; Glassel, Peter; Gomez, Ramon; Gonzalez Ferreiro, Elena; Gonzalez-Trueba, Laura Helena; Gonzalez-Zamora, Pedro; Gorbunov, Sergey; Goswami, Ankita; Gotovac, Sven; Grabski, Varlen; Graczykowski, Lukasz Kamil; Grajcarek, Robert; Grelli, Alessandro; Grigoras, Alina Gabriela; Grigoras, Costin; Grigoriev, Vladislav; Grigoryan, Ara; Grigoryan, Smbat; Grinyov, Boris; Grion, Nevio; Gros, Philippe; Grosse-Oetringhaus, Jan Fiete; Grossiord, Jean-Yves; Grosso, Raffaele; Guber, Fedor; Guernane, Rachid; Guerra Gutierrez, Cesar; Guerzoni, Barbara; Guilbaud, Maxime Rene Joseph; Gulbrandsen, Kristjan Herlache; Gunji, Taku; Gupta, Ramni; Gupta, Anik; Gutbrod, Hans; Haaland, Oystein Senneset; Hadjidakis, Cynthia Marie; Haiduc, Maria; Hamagaki, Hideki; Hamar, Gergoe; Han, Byounghee; Hanratty, Luke David; Hansen, Alexander; Harmanova, Zuzana; Harris, John William; Hartig, Matthias; Hasegan, Dumitru; Hatzifotiadou, Despoina; Hayrapetyan, Arsen; Heckel, Stefan Thomas; Heide, Markus Ansgar; Helstrup, Haavard; Herghelegiu, Andrei Ionut; Herrera Corral, Gerardo Antonio; Herrmann, Norbert; Hess, Benjamin Andreas; Hetland, Kristin Fanebust; Hicks, Bernard; Hille, Per Thomas; Hippolyte, Boris; Horaguchi, Takuma; Hori, Yasuto; Hristov, Peter Zahariev; Hrivnacova, Ivana; Huang, Meidana; Humanic, Thomas; Hwang, Dae Sung; Ichou, Raphaelle; Ilkaev, Radiy; Ilkiv, Iryna; Inaba, Motoi; Incani, Elisa; Innocenti, Pier Giorgio; Innocenti, Gian Michele; Ippolitov, Mikhail; Irfan, Muhammad; Ivan, Cristian George; Ivanov, Vladimir; Ivanov, Marian; Ivanov, Andrey; Ivanytskyi, Oleksii; Jacobs, Peter; Jang, Haeng Jin; Janik, Malgorzata Anna; Janik, Rudolf; Jayarathna, Sandun; Jena, Satyajit; Jha, Deeptanshu Manu; Jimenez Bustamante, Raul Tonatiuh; Jirden, Lennart; Jones, Peter Graham; Jung, Hyung Taik; Jusko, Anton; Kaidalov, Alexei; Kakoyan, Vanik; Kalcher, Sebastian; Kalinak, Peter; Kalliokoski, Tuomo Esa Aukusti; Kalweit, Alexander Philipp; Kang, Ju Hwan; Kaplin, Vladimir; Karasu Uysal, Ayben; Karavichev, Oleg; Karavicheva, Tatiana; Karpechev, Evgeny; Kazantsev, Andrey; Kebschull, Udo Wolfgang; Keidel, Ralf; Khan, Shuaib Ahmad; Khan, Palash; Khan, Mohisin Mohammed; Khanzadeev, Alexei; Kharlov, Yury; Kileng, Bjarte; Kim, Minwoo; Kim, Se Yong; Kim, Dong Jo; Kim, Do Won; Kim, Jonghyun; Kim, Jin Sook; Kim, Taesoo; Kim, Mimae; Kim, Beomkyu; Kirsch, Stefan; Kisel, Ivan; Kiselev, Sergey; Kisiel, Adam Ryszard; Klay, Jennifer Lynn; Klein, Jochen; Klein-Bosing, Christian; Kliemant, Michael; Kluge, Alexander; Knichel, Michael Linus; Knospe, Anders Garritt; Koch, Kathrin; Kohler, Markus; Kollegger, Thorsten; Kolojvari, Anatoly; Kondratiev, Valery; Kondratyeva, Natalia; Konevskih, Artem; Kour, Ravjeet; Kowalski, Marek; Kox, Serge; Koyithatta Meethaleveedu, Greeshma; Kral, Jiri; Kralik, Ivan; Kramer, Frederick; Kraus, Ingrid Christine; Kravcakova, Adela; Krawutschke, Tobias; Krelina, Michal; Kretz, Matthias; Krivda, Marian; Krizek, Filip; Krus, Miroslav; Kryshen, Evgeny; Krzewicki, Mikolaj; Kucheriaev, Yury; Kugathasan, Thanushan; Kuhn, Christian Claude; Kuijer, Paul; Kulakov, Igor; Kumar, Jitendra; Kurashvili, Podist; Kurepin, A; Kurepin, AB; Kuryakin, Alexey; Kushpil, Vasily; Kushpil, Svetlana; Kvaerno, Henning; Kweon, Min Jung; Kwon, Youngil; Ladron de Guevara, Pedro; Lakomov, Igor; Langoy, Rune; La Pointe, Sarah Louise; Lara, Camilo Ernesto; Lardeux, Antoine Xavier; La Rocca, Paola; Lea, Ramona; Le Bornec, Yves; Lechman, Mateusz; Lee, Ki Sang; Lee, Sung Chul; Lee, Graham Richard; Lefevre, Frederic; Lehnert, Joerg Walter; Lenhardt, Matthieu Laurent; Lenti, Vito; Leon, Hermes; Leoncino, Marco; Leon Monzon, Ildefonso; Leon Vargas, Hermes; Levai, Peter; Lien, Jorgen; Lietava, Roman; Lindal, Svein; Lindenstruth, Volker; Lippmann, Christian; Lisa, Michael Annan; Liu, Lijiao; Loggins, Vera; Loginov, Vitaly; Lohn, Stefan Bernhard; Lohner, Daniel; Loizides, Constantinos; Loo, Kai Krister; Lopez, Xavier Bernard; Lopez Torres, Ernesto; Lovhoiden, Gunnar; Lu, Xianguo; Luettig, Philipp; Lunardon, Marcello; Luo, Jiebin; Luparello, Grazia; Luquin, Lionel; Luzzi, Cinzia; Ma, Ke; Ma, Rongrong; Madagodahettige-Don, Dilan Minthaka; Maevskaya, Alla; Mager, Magnus; Mahapatra, Durga Prasad; Maire, Antonin; Malaev, Mikhail; Maldonado Cervantes, Ivonne Alicia; Malinina, Ludmila; Mal'Kevich, Dmitry; Malzacher, Peter; Mamonov, Alexander; Mangotra, Lalit Kumar; Manko, Vladislav; Manso, Franck; Manzari, Vito; Mao, Yaxian; Marchisone, Massimiliano; Mares, Jiri; Margagliotti, Giacomo Vito; Margotti, Anselmo; Marin, Ana Maria; Marin Tobon, Cesar Augusto; Markert, Christina; Marquard, Marco; Martashvili, Irakli; Martinengo, Paolo; Martinez, Mario Ivan; Martinez Davalos, Arnulfo; Martinez Garcia, Gines; Martynov, Yevgen; Mas, Alexis Jean-Michel; Masciocchi, Silvia; Masera, Massimo; Masoni, Alberto; Massacrier, Laure Marie; Mastroserio, Annalisa; Matthews, Zoe Louise; Matyja, Adam Tomasz; Mayer, Christoph; Mazer, Joel; Mazzoni, Alessandra Maria; Meddi, Franco; Menchaca-Rocha, Arturo Alejandro; Mercado Perez, Jorge; Meres, Michal; Miake, Yasuo; Milano, Leonardo; Milosevic, Jovan; Mischke, Andre; Mishra, Aditya Nath; Miskowiec, Dariusz; Mitu, Ciprian Mihai; Mlynarz, Jocelyn; Mohanty, Bedangadas; Molnar, Levente; Montano Zetina, Luis Manuel; Monteno, Marco; Montes, Esther; Moon, Taebong; Morando, Maurizio; Moreira De Godoy, Denise Aparecida; Moretto, Sandra; Morsch, Andreas; Muccifora, Valeria; Mudnic, Eugen; Muhuri, Sanjib; Mukherjee, Maitreyee; Muller, Hans; Munhoz, Marcelo; Musa, Luciano; Musso, Alfredo; Nandi, Basanta Kumar; Nania, Rosario; Nappi, Eugenio; Nattrass, Christine; Navin, Sparsh; Nayak, Tapan Kumar; Nazarenko, Sergey; Nedosekin, Alexander; Nicassio, Maria; Niculescu, Mihai; Nielsen, Borge Svane; Niida, Takafumi; Nikolaev, Sergey; Nikolic, Vedran; Nikulin, Vladimir; Nikulin, Sergey; Nilsen, Bjorn Steven; Nilsson, Mads Stormo; Noferini, Francesco; Nomokonov, Petr; Nooren, Gerardus; Novitzky, Norbert; Nyanin, Alexandre; Nyatha, Anitha; Nygaard, Casper; Nystrand, Joakim Ingemar; Ochirov, Alexander; Oeschler, Helmut Oskar; Oh, Sun Kun; Oh, Saehanseul; Oleniacz, Janusz; Oppedisano, Chiara; Ortiz Velasquez, Antonio; Ortona, Giacomo; Oskarsson, Anders Nils Erik; Ostrowski, Piotr Krystian; Otwinowski, Jacek Tomasz; Oyama, Ken; Ozawa, Kyoichiro; Pachmayer, Yvonne Chiara; Pachr, Milos; Padilla, Fatima; Pagano, Paola; Paic, Guy; Painke, Florian; Pajares, Carlos; Pal, Susanta Kumar; Palaha, Arvinder Singh; Palmeri, Armando; Papikyan, Vardanush; Pappalardo, Giuseppe; Park, Woo Jin; Passfeld, Annika; Pastircak, Blahoslav; Patalakha, Dmitri Ivanovich; Paticchio, Vincenzo; Pavlinov, Alexei; Pawlak, Tomasz Jan; Peitzmann, Thomas; Pereira Da Costa, Hugo Denis Antonio; Pereira De Oliveira Filho, Elienos; Peresunko, Dmitri; Perez Lara, Carlos Eugenio; Perez Lezama, Edgar; Perini, Diego; Perrino, Davide; Peryt, Wiktor Stanislaw; Pesci, Alessandro; Peskov, Vladimir; Pestov, Yury; Petracek, Vojtech; Petran, Michal; Petris, Mariana; Petrov, Plamen Rumenov; Petrovici, Mihai; Petta, Catia; Piano, Stefano; Piccotti, Anna; Pikna, Miroslav; Pillot, Philippe; Pinazza, Ombretta; Pinsky, Lawrence; Pitz, Nora; Piyarathna, Danthasinghe; Planinic, Mirko; Ploskon, Mateusz Andrzej; Pluta, Jan Marian; Pocheptsov, Timur; Pochybova, Sona; Podesta Lerma, Pedro Luis Manuel; Poghosyan, Martin; Polak, Karel; Polichtchouk, Boris; Pop, Amalia; Porteboeuf-Houssais, Sarah; Pospisil, Vladimir; Potukuchi, Baba; Prasad, Sidharth Kumar; Preghenella, Roberto; Prino, Francesco; Pruneau, Claude Andre; Pshenichnov, Igor; Puddu, Giovanna; Pulvirenti, Alberto; Punin, Valery; Putis, Marian; Putschke, Jorn Henning; Quercigh, Emanuele; Qvigstad, Henrik; Rachevski, Alexandre; Rademakers, Alphonse; Raiha, Tomi Samuli; Rak, Jan; Rakotozafindrabe, Andry Malala; Ramello, Luciano; Ramirez Reyes, Abdiel; Raniwala, Rashmi; Raniwala, Sudhir; Rasanen, Sami Sakari; Rascanu, Bogdan Theodor; Rathee, Deepika; Read, Kenneth Francis; Real, Jean-Sebastien; Redlich, Krzysztof; Rehman, Attiq Ur; Reichelt, Patrick; Reicher, Martijn; Renfordt, Rainer Arno Ernst; Reolon, Anna Rita; Reshetin, Andrey; Rettig, Felix Vincenz; Revol, Jean-Pierre; Reygers, Klaus Johannes; Riccati, Lodovico; Ricci, Renato Angelo; Richert, Tuva; Richter, Matthias Rudolph; Riedler, Petra; Riegler, Werner; Riggi, Francesco; Rodrigues Fernandes Rabacal, Bartolomeu; Rodriguez Cahuantzi, Mario; Rodriguez Manso, Alis; Roed, Ketil; Rohr, David; Rohrich, Dieter; Romita, Rosa; Ronchetti, Federico; Rosnet, Philippe; Rossegger, Stefan; Rossi, Andrea; Roy, Christelle Sophie; Roy, Pradip Kumar; Rubio Montero, Antonio Juan; Rui, Rinaldo; Russo, Riccardo; Ryabinkin, Evgeny; Rybicki, Andrzej; Sadovsky, Sergey; Safarik, Karel; Sahoo, Raghunath; Sahu, Pradip Kumar; Saini, Jogender; Sakaguchi, Hiroaki; Sakai, Shingo; Sakata, Dosatsu; Salgado, Carlos Albert; Salzwedel, Jai; Sambyal, Sanjeev Singh; Samsonov, Vladimir; Sanchez Castro, Xitzel; Sandor, Ladislav; Sandoval, Andres; Sano, Masato; Sano, Satoshi; Santo, Rainer; Santoro, Romualdo; Sarkamo, Juho Jaako; Scapparone, Eugenio; Scarlassara, Fernando; Scharenberg, Rolf Paul; Schiaua, Claudiu Cornel; Schicker, Rainer Martin; Schmidt, Hans Rudolf; Schmidt, Christian Joachim; Schreiner, Steffen; Schuchmann, Simone; Schukraft, Jurgen; Schutz, Yves Roland; Schwarz, Kilian Eberhard; Schweda, Kai Oliver; Scioli, Gilda; Scomparin, Enrico; Scott, Rebecca; Segato, Gianfranco; Selioujenkov, Ilya; Senyukov, Serhiy; Seo, Jeewon; Serci, Sergio; Serradilla, Eulogio; Sevcenco, Adrian; Shabetai, Alexandre; Shabratova, Galina; Shahoyan, Ruben; Sharma, Satish; Sharma, Natasha; Sharma, Rohini; Shigaki, Kenta; Shimomura, Maya; Shtejer, Katherin; Sibiriak, Yury; Siciliano, Melinda; Sicking, Eva; Siddhanta, Sabyasachi; Siemiarczuk, Teodor; Silvermyr, David Olle Rickard; Silvestre, Catherine; Simatovic, Goran; Simonetti, Giuseppe; Singaraju, Rama Narayana; Singh, Ranbir; Singha, Subhash; Singhal, Vikas; Sinha, Bikash; Sinha, Tinku; Sitar, Branislav; Sitta, Mario; Skaali, Bernhard; Skjerdal, Kyrre; Smakal, Radek; Smirnov, Nikolai; Snellings, Raimond; Sogaard, Carsten; Soltz, Ron Ariel; Son, Hyungsuk; Song, Myunggeun; Song, Jihye; Soos, Csaba; Soramel, Francesca; Sputowska, Iwona; Spyropoulou-Stassinaki, Martha; Srivastava, Brijesh Kumar; Stachel, Johanna; Stan, Ionel; Stan, Ionel; Stefanek, Grzegorz; Steinpreis, Matthew; Stenlund, Evert Anders; Steyn, Gideon Francois; Stiller, Johannes Hendrik; Stocco, Diego; Stolpovskiy, Mikhail; Strmen, Peter; Suaide, Alexandre Alarcon do Passo; Subieta Vasquez, Martin Alfonso; Sugitate, Toru; Suire, Christophe Pierre; Sultanov, Rishat; Sumbera, Michal; Susa, Tatjana; Symons, Timothy; Szanto de Toledo, Alejandro; Szarka, Imrich; Szczepankiewicz, Adam; Szostak, Artur Krzysztof; Szymanski, Maciej; Takahashi, Jun; Tapia Takaki, Daniel Jesus; Tauro, Arturo; Tejeda Munoz, Guillermo; Telesca, Adriana; Terrevoli, Cristina; Thader, Jochen Mathias; Thomas, Deepa; Tieulent, Raphael Noel; Timmins, Anthony; Tlusty, David; Toia, Alberica; Torii, Hisayuki; Toscano, Luca; Trubnikov, Victor; Truesdale, David Christopher; Trzaska, Wladyslaw Henryk; Tsuji, Tomoya; Tumkin, Alexandr; Turrisi, Rosario; Tveter, Trine Spedstad; Ulery, Jason Glyndwr; Ullaland, Kjetil; Ulrich, Jochen; Uras, Antonio; Urban, Jozef; Urciuoli, Guido Marie; Usai, Gianluca; Vajzer, Michal; Vala, Martin; Valencia Palomo, Lizardo; Vallero, Sara; Vande Vyvre, Pierre; van Leeuwen, Marco; Vannucci, Luigi; Vargas, Aurora Diozcora; Varma, Raghava; Vasileiou, Maria; Vasiliev, Andrey; Vechernin, Vladimir; Veldhoen, Misha; Venaruzzo, Massimo; Vercellin, Ermanno; Vergara, Sergio; Vernet, Renaud; Verweij, Marta; Vickovic, Linda; Viesti, Giuseppe; Vilakazi, Zabulon; Villalobos Baillie, Orlando; Vinogradov, Yury; Vinogradov, Leonid; Vinogradov, Alexander; Virgili, Tiziano; Viyogi, Yogendra; Vodopianov, Alexander; Voloshin, Kirill; Voloshin, Sergey; Volpe, Giacomo; von Haller, Barthelemy; Vranic, Danilo; vrebekk, Gaute; Vrlakova, Janka; Vulpescu, Bogdan; Vyushin, Alexey; Wagner, Boris; Wagner, Vladimir; Wan, Renzhuo; Wang, Mengliang; Wang, Dong; Wang, Yifei; Wang, Yaping; Watanabe, Kengo; Weber, Michael; Wessels, Johannes; Westerhoff, Uwe; Wiechula, Jens; Wikne, Jon; Wilde, Martin Rudolf; Wilk, Alexander; Wilk, Grzegorz Andrzej; Williams, Crispin; Windelband, Bernd Stefan; Xaplanteris Karampatsos, Leonidas; Yaldo, Chris G; Yamaguchi, Yorito; Yang, Shiming; Yang, Hongyan; Yasnopolsky, Stanislav; Yi, JunGyu; Yin, Zhongbao; Yoo, In-Kwon; Yoon, Jongik; Yu, Weilin; Yuan, Xianbao; Yushmanov, Igor; Zaccolo, Valentina; Zach, Cenek; Zampolli, Chiara; Zaporozhets, Sergey; Zarochentsev, Andrey; Zavada, Petr; Zaviyalov, Nikolai; Zbroszczyk, Hanna Paulina; Zelnicek, Pierre; Zgura, Sorin Ion; Zhalov, Mikhail; Zhang, Xiaoming; Zhang, Haitao; Zhou, You; Zhou, Fengchu; Zhou, Daicui; Zhu, Jianlin; Zhu, Jianhui; Zhu, Xiangrong; Zichichi, Antonino; Zimmermann, Alice; Zinovjev, Gennady; Zoccarato, Yannick Denis; Zynovyev, Mykhaylo; Zyzak, Maksym

2013-01-01

Measurements of cross sections of inelastic and diffractive processes in proton--proton collisions at LHC energies were carried out with the ALICE detector. The fractions of diffractive processes in inelastic collisions were determined from a study of gaps in charged particle pseudorapidity distributions: for single diffraction (diffractive mass $M_X 3$) $\\sigma_{\\rm DD}/\\sigma_{\\rm INEL} = 0.11 \\pm 0.03, 0.12 \\pm 0.05$, and $0.12^{+0.05}_{-0.04}$, respectively at $\\sqrt{s} = 0.9, 2.76$, and 7 TeV. To measure the inelastic cross section, beam properties were determined with van der Meer scans, and, using a simulation of diffraction adjusted to data, the following values were obtained: $\\sigma_{\\rm INEL} = 62.8^{+2.4}_{-4.0} (model) \\pm 1.2 (lumi)$ mb at $\\sqrt{s} =$ 2.76 TeV and $73.2^{+2.0}_{-4.6} (model) \\pm 2.6 (lumi)$ mb at $\\sqrt{s}$ = 7 TeV. The single- and double-diffractive cross sections were calculated combining relative rates of diffraction with inelastic cross sections. The results are compared t...

Quantitative measurement of phase variation amplitude of ultrasonic diffraction grating based on diffraction spectral analysis

Energy Technology Data Exchange (ETDEWEB)

Pan, Meiyan, E-mail: yphantomohive@gmail.com; Zeng, Yingzhi; Huang, Zuohua, E-mail: zuohuah@163.com [Laboratory of Quantum Engineering and Quantum Materials, School of Physics and Telecommunication Engineering, South China Normal University, Guangzhou, Guangdong 510006 (China)

2014-09-15

A new method based on diffraction spectral analysis is proposed for the quantitative measurement of the phase variation amplitude of an ultrasonic diffraction grating. For a traveling wave, the phase variation amplitude of the grating depends on the intensity of the zeroth- and first-order diffraction waves. By contrast, for a standing wave, this amplitude depends on the intensity of the zeroth-, first-, and second-order diffraction waves. The proposed method is verified experimentally. The measured phase variation amplitude ranges from 0 to 2π, with a relative error of approximately 5%. A nearly linear relation exists between the phase variation amplitude and driving voltage. Our proposed method can also be applied to ordinary sinusoidal phase grating.

Undergraduate experiment with fractal diffraction gratings

International Nuclear Information System (INIS)

Monsoriu, Juan A; Furlan, Walter D; Pons, Amparo; Barreiro, Juan C; Gimenez, Marcos H

2011-01-01

We present a simple diffraction experiment with fractal gratings based on the triadic Cantor set. Diffraction by fractals is proposed as a motivating strategy for students of optics in the potential applications of optical processing. Fraunhofer diffraction patterns are obtained using standard equipment present in most undergraduate physics laboratories and compared with those obtained with conventional periodic gratings. It is shown that fractal gratings produce self-similar diffraction patterns which can be evaluated analytically. Good agreement is obtained between experimental and numerical results.

Neutron diffraction studies of glasses

International Nuclear Information System (INIS)

Wright, A.C.

1987-01-01

A survey is given of the application of neutron diffraction to structural studies of oxide and halide glasses. As with crystalline materials, neutron and X-ray diffraction are the major structural probes for glasses and other amorphous solids, particularly in respect of intermediate range order. The glasses discussed mostly have structures which are dominated by a network in which the bonding is predominantly covalent. The examples discussed demonstrate the power of the neutron diffraction technique in the investigation of the structures of inorganic glasses. The best modern diffraction experiments are capable of providing accurate data with high real space resolution, which if used correctly, are an extremely fine filter for the various structural models proposed in the literature. 42 refs

Software of structure experiMents in a neutron time-of-flight diffractometer

International Nuclear Information System (INIS)

Balagurov, A.M.; Dlouga, M.; Zlokazov, V.B.; Mironova, G.M.

1978-01-01

A set of programs is discussed to be used in diffraction experiment in a neutron time-of-flight diffractometer. The DIFRAT program, which processes spectra of poly and monocrystals, locates all spectrum maxima and assesses their width on the basis of given experimental data and elementary cell parameters. Accurate location of maxima, evaluation of their area and width is done by the IREAK program. The most important feature of this program is a capability to set an experimental model of maxima patterns. The EXPDAT program is developed to investigate structural characteristics of a sample. It calculates corrections for absorbtion and extinction

A structural view of Pd model catalysts : high-pressure surface X-Ray diffraction

NARCIS (Netherlands)

Rijn, Richard van

2012-01-01

This thesis describes the development of a combined high-pressure/ultrahigh-vacuum flow reactor for the study of model catalysts by means of surface x-ray diffraction and grazing incidence small angle scattering. The system was used to measure a stability diagram for the different oxide phases

High-energy particle diffraction

International Nuclear Information System (INIS)

Barone, V.; Predazzi, E.

2002-01-01

This monograph gives a comprehensive and up-to-date overview of soft and hard diffraction processes in strong interaction physics. The first part covers the general formalism (the optical analogy, the eikonal picture, high-energy kinematics, S-matrix theory) and soft hadron-hadron scattering (including the Regge theory) in a complete and mature presentation. It can be used as a textbook in particle physics classes. The remainder of the book is devoted to the 'new diffraction': the pomeron in QCD, low-x physics, diffractive deep inelastic scattering and related processes, jet production etc. It presents recent results and experimental findings and their phenomenological interpretations. This part addresses graduate students as well as researchers. (orig.)

Comparative study of structural properties of trehalose water solutions by neutron diffraction, synchrotron radiation and simulation

Energy Technology Data Exchange (ETDEWEB)

Cesaro, A.; Magazu, V.; Migliardo, F.; Sussich, F.; Vadala, M

2004-07-15

Neutron diffraction measurements combined with H/D substitution have been performed on trehalose aqueous solutions as a function of temperature and concentration by using the SANDALS diffractometer at ISIS Facility (UK). The findings point out a high capability of trehalose to strongly affect the tetrahedral hydrogen bond network of water. The neutron diffraction results are also compared with simulation and experimental data obtained by synchrotron radiation on the phospholipid bilayer membranes (DPPC)/trehalose/H{sub 2}O ternary system.

Quantitative convergent beam electron diffraction measurements of bonding in alumina

International Nuclear Information System (INIS)

Johnson, A.W.S.

2002-01-01

Full text: The QCBED technique of measuring accurate structure factors has been made practical by advances in energy filtering, computing and in the accurate measurement of intensity. Originally attempted in 1965 by the late Peter Goodman (CSIRO, Melbourne) while working with Gunter Lehmpfuhl (Fritz Haber Institut, Berlin), QCBED has been successfully developed and tested in the last decade on simple structures such as Si and MgO. Our work on Alumina is a step up in complexity and has shown that extinction in X-ray diffraction is not correctable to the precision required. In combination with accurate X-ray diffraction, QCBED promises to revolutionize the accuracy of bonding charge density measurements, experimental results which are of significance in the development of Density Functional Theory used in predictive chemistry. Copyright (2002) Australian Society for Electron Microscopy Inc

Undergraduate Experiment with Fractal Diffraction Gratings

Science.gov (United States)

Monsoriu, Juan A.; Furlan, Walter D.; Pons, Amparo; Barreiro, Juan C.; Gimenez, Marcos H.

2011-01-01

We present a simple diffraction experiment with fractal gratings based on the triadic Cantor set. Diffraction by fractals is proposed as a motivating strategy for students of optics in the potential applications of optical processing. Fraunhofer diffraction patterns are obtained using standard equipment present in most undergraduate physics…

Diffraction-based overlay metrology for double patterning technologies

Science.gov (United States)

Dasari, Prasad; Korlahalli, Rahul; Li, Jie; Smith, Nigel; Kritsun, Oleg; Volkman, Cathy

2009-03-01

The extension of optical lithography to 32nm and beyond is made possible by Double Patterning Techniques (DPT) at critical levels of the process flow. The ease of DPT implementation is hindered by increased significance of critical dimension uniformity and overlay errors. Diffraction-based overlay (DBO) has shown to be an effective metrology solution for accurate determination of the overlay errors associated with double patterning [1, 2] processes. In this paper we will report its use in litho-freeze-litho-etch (LFLE) and spacer double patterning technology (SDPT), which are pitch splitting solutions that reduce the significance of overlay errors. Since the control of overlay between various mask/level combinations is critical for fabrication, precise and accurate assessment of errors by advanced metrology techniques such as spectroscopic diffraction based overlay (DBO) and traditional image-based overlay (IBO) using advanced target designs will be reported. A comparison between DBO, IBO and CD-SEM measurements will be reported. . A discussion of TMU requirements for 32nm technology and TMU performance data of LFLE and SDPT targets by different overlay approaches will be presented.

Two-dimensional x-ray diffraction

CERN Document Server

He, Bob B

2009-01-01

Written by one of the pioneers of 2D X-Ray Diffraction, this useful guide covers the fundamentals, experimental methods and applications of two-dimensional x-ray diffraction, including geometry convention, x-ray source and optics, two-dimensional detectors, diffraction data interpretation, and configurations for various applications, such as phase identification, texture, stress, microstructure analysis, crystallinity, thin film analysis and combinatorial screening. Experimental examples in materials research, pharmaceuticals, and forensics are also given. This presents a key resource to resea

Diffraction dissociation at the LHC

Energy Technology Data Exchange (ETDEWEB)

Jenkovszky, Laszlo [Bogolyubov Institute for Theoretical Physics (BITP), Ukrainian National Academy of Sciences 14-b, Metrolohichna str., Kiev, 03680, Ukraine and Wigner Research Centre for Physics, Hungarian Academy of Sciences 1525 Budapest, POB 49 (Hungary); Orava, Risto [Institute of Physics, Division of Elementary Particle Physics, P.O. Box 64 (Gustaf Haellstroeminkatu 2a), FI-00014 University of Helsinki, Finland and CERN, CH-1211 Geneva 23 (Switzerland); Salii, Andrii [Bogolyubov Institute for Theoretical Physics (BITP), Ukrainian National Academy of Sciences 14-b, Metrolohichna str., Kiev, 03680 (Ukraine)

2013-04-15

We report on recent calculations of low missing mass single (SD) and double (DD) diffractive dissociation at LHC energies. The calculations are based on a dual-Regge model, dominated by a single Pomeron exchange. The diffractively excited states lie on the nucleon trajectory N*, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single-and double diffraction dissociation in the kinematical range of present and future LHC measurements are given.

Diffraction dissociation at the LHC

International Nuclear Information System (INIS)

Jenkovszky, László; Orava, Risto; Salii, Andrii

2013-01-01

We report on recent calculations of low missing mass single (SD) and double (DD) diffractive dissociation at LHC energies. The calculations are based on a dual-Regge model, dominated by a single Pomeron exchange. The diffractively excited states lie on the nucleon trajectory N*, appended by the isolated Roper resonance. Detailed predictions for the squared momentum transfer and missing mass dependence of the differential and integrated single-and double diffraction dissociation in the kinematical range of present and future LHC measurements are given.

Flight Test Implementation of a Second Generation Intelligent Flight Control System

Science.gov (United States)

Williams-Hayes, Peggy S.

2005-01-01

The NASA F-15 Intelligent Flight Control System project team has developed a series of flight control concepts designed to demonstrate the benefits of a neural network-based adaptive controller. The objective of the team was to develop and flight-test control systems that use neural network technology, to optimize the performance of the aircraft under nominal conditions, and to stabilize the aircraft under failure conditions. Failure conditions include locked or failed control surfaces as well as unforeseen damage that might occur to the aircraft in flight. The Intelligent Flight Control System team is currently in the process of implementing a second generation control scheme, collectively known as Generation 2 or Gen 2, for flight testing on the NASA F-15 aircraft. This report describes the Gen 2 system as implemented by the team for flight test evaluation. Simulation results are shown which describe the experiment to be performed in flight and highlight the ways in which the Gen 2 system meets the defined objectives.

The TORCH time-of-flight detector

Energy Technology Data Exchange (ETDEWEB)

Harnew, N., E-mail: Neville.Harnew@physics.ox.ac.uk [University of Oxford, Denys Wilkinson Building, 1 Keble Road, Oxford OX1 3RH (United Kingdom); Brook, N. [University College London, Department of Physics & Astronomy, Gower Street, London WC1E 6BT (United Kingdom); Castillo García, L. [CERN, PH Department, CH-1211 Geneva 23 (Switzerland); Laboratory for High Energy Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland); Cussans, D. [H.H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL (United Kingdom); Föhl, K.; Forty, R.; Frei, C. [CERN, PH Department, CH-1211 Geneva 23 (Switzerland); Gao, R. [University of Oxford, Denys Wilkinson Building, 1 Keble Road, Oxford OX1 3RH (United Kingdom); Gys, T.; Piedigrossi, D. [CERN, PH Department, CH-1211 Geneva 23 (Switzerland); Rademacker, J.; Ros Garcia, A.; Dijk, M. van [H.H. Wills Physics Laboratory, University of Bristol, Bristol BS8 1TL (United Kingdom)

2016-07-11

The TORCH time-of-flight detector is being developed to provide particle identification between 2 and 10 GeV/c momentum over a flight distance of 10 m. TORCH is designed for large-area coverage, up to 30 m{sup 2}, and has a DIRC-like construction. The goal is to achieve a 15 ps time-of-flight resolution per incident particle by combining arrival times from multiple Cherenkov photons produced within quartz radiator plates of 10 mm thickness. A four-year R&D programme is underway with an industrial partner (Photek, UK) to produce 53×53 mm{sup 2} Micro-Channel Plate (MCP) detectors for the TORCH application. The MCP-PMT will provide a timing accuracy of 40 ps per photon and it will have a lifetime of up to at least 5 Ccm{sup −2} of integrated anode charge by utilizing an Atomic Layer Deposition (ALD) coating. The MCP will be read out using charge division with customised electronics incorporating the NINO chipset. Laboratory results on prototype MCPs are presented. The construction of a prototype TORCH module and its simulated performance are also described.

Three-dimensional rotation electron diffraction: software RED for automated data collection and data processing.

Science.gov (United States)

Wan, Wei; Sun, Junliang; Su, Jie; Hovmöller, Sven; Zou, Xiaodong

2013-12-01

Implementation of a computer program package for automated collection and processing of rotation electron diffraction (RED) data is described. The software package contains two computer programs: RED data collection and RED data processing. The RED data collection program controls the transmission electron microscope and the camera. Electron beam tilts at a fine step (0.05-0.20°) are combined with goniometer tilts at a coarse step (2.0-3.0°) around a common tilt axis, which allows a fine relative tilt to be achieved between the electron beam and the crystal in a large tilt range. An electron diffraction (ED) frame is collected at each combination of beam tilt and goniometer tilt. The RED data processing program processes three-dimensional ED data generated by the RED data collection program or by other approaches. It includes shift correction of the ED frames, peak hunting for diffraction spots in individual ED frames and identification of these diffraction spots as reflections in three dimensions. Unit-cell parameters are determined from the positions of reflections in three-dimensional reciprocal space. All reflections are indexed, and finally a list with hkl indices and intensities is output. The data processing program also includes a visualizer to view and analyse three-dimensional reciprocal lattices reconstructed from the ED frames. Details of the implementation are described. Data collection and data processing with the software RED are demonstrated using a calcined zeolite sample, silicalite-1. The structure of the calcined silicalite-1, with 72 unique atoms, could be solved from the RED data by routine direct methods.

Dynamics from diffraction

International Nuclear Information System (INIS)

Goodwin, Andrew L.; Tucker, Matthew G.; Cope, Elizabeth R.; Dove, Martin T.; Keen, David A.

2006-01-01

We explore the possibility that detailed dynamical information might be extracted from powder diffraction data. Our focus is a recently reported technique that employs statistical analysis of atomistic configurations to calculate dynamical properties from neutron total scattering data. We show that it is possible to access the phonon dispersion of low-frequency modes using such an approach, without constraining the results in terms of some pre-defined dynamical model. The high-frequency regions of the phonon spectrum are found to be less well preserved in the diffraction data

Contribution to diffraction theory; Contribution a la theorie de la diffraction

Energy Technology Data Exchange (ETDEWEB)

Chako, N [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1966-11-01

In a first part, we have given a general and detailed treatment of the modern theory of diffraction. The rigorous theory is formulated as a boundary value problem of the wave equation or Maxwell equations. However, up to the present time, such a program of treating diffraction by optical systems, even for simple optical instruments, has not been realized due to the complicated character of the boundary conditions. The recent developments show clearly the nature of the approximation of the classical theories originally due to Fresnel and Young, later formulated in a rigorous manner by Kirchhoff and Rubinowicz, respectively and, at the same time the insufficiency of these theories in explaining a number of diffraction phenomena. Furthermore, we have made a study of the limitations of the approximate theories and the recent attempts to improve these. The second part is devoted to a general mathematical treatment of the theory of diffraction of optical systems including aberrations. After a general and specific analysis of geometrical and wave aberrations along classical and modern (Nijboer) lines, we have been able to evaluate the diffraction integrals representing the image field at any point in image space explicitly, when the aberrations are small. Our formulas are the generalisations of all anterior results obtained by previous investigators. Moreover, we have discussed the Zernike-Nijboer theory of aberration and generalised it not only for rotational systems, but also for non-symmetric systems as well, including the case of non circular apertures. The extension to non-circular apertures is done by introducing orthogonal functions or polynomials over such aperture shapes. So far the results are valid for small aberrations, that is to say, where the deformation of the real wave front emerging from the optical system is less than a wave length of light or of the electromagnetic wave from the ideal wave front. If the aberrations are large, then one must employ the

Contribution to diffraction theory; Contribution a la theorie de la diffraction

Energy Technology Data Exchange (ETDEWEB)

Chako, N. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1966-11-01

In a first part, we have given a general and detailed treatment of the modern theory of diffraction. The rigorous theory is formulated as a boundary value problem of the wave equation or Maxwell equations. However, up to the present time, such a program of treating diffraction by optical systems, even for simple optical instruments, has not been realized due to the complicated character of the boundary conditions. The recent developments show clearly the nature of the approximation of the classical theories originally due to Fresnel and Young, later formulated in a rigorous manner by Kirchhoff and Rubinowicz, respectively and, at the same time the insufficiency of these theories in explaining a number of diffraction phenomena. Furthermore, we have made a study of the limitations of the approximate theories and the recent attempts to improve these. The second part is devoted to a general mathematical treatment of the theory of diffraction of optical systems including aberrations. After a general and specific analysis of geometrical and wave aberrations along classical and modern (Nijboer) lines, we have been able to evaluate the diffraction integrals representing the image field at any point in image space explicitly, when the aberrations are small. Our formulas are the generalisations of all anterior results obtained by previous investigators. Moreover, we have discussed the Zernike-Nijboer theory of aberration and generalised it not only for rotational systems, but also for non-symmetric systems as well, including the case of non circular apertures. The extension to non-circular apertures is done by introducing orthogonal functions or polynomials over such aperture shapes. So far the results are valid for small aberrations, that is to say, where the deformation of the real wave front emerging from the optical system is less than a wave length of light or of the electromagnetic wave from the ideal wave front. If the aberrations are large, then one must employ the

In-Flight spacecraft magnetic field monitoring using scalar/vector gradiometry

DEFF Research Database (Denmark)

Primdahl, Fritz; Risbo, Torben; Merayo, José M.G.

2006-01-01

Earth magnetic field mapping from planetary orbiting satellites requires a spacecraft magnetic field environment control program combined with the deployment of the magnetic sensors on a boom in order to reduce the measurement error caused by the local spacecraft field. Magnetic mapping missions...... (Magsat, Oersted, CHAMP, SAC-C MMP and the planned ESA Swarm project) carry a vector magnetometer and an absolute scalar magnetometer for in-flight calibration of the vector magnetometer scale values and for monitoring of the inter-axes angles and offsets over time intervals from months to years...... sensors onboard the Oersted satellite. For Oersted, a large difference between the pre-flight determined spacecraft magnetic field and the in-flight estimate exists causing some concern about the general applicability of the dual sensors technique....

Approach for Structurally Clearing an Adaptive Compliant Trailing Edge Flap for Flight

Science.gov (United States)

Miller, Eric J.; Lokos, William A.; Cruz, Josue; Crampton, Glen; Stephens, Craig A.; Kota, Sridhar; Ervin, Gregory; Flick, Pete

2015-01-01

The Adaptive Compliant Trailing Edge (ACTE) flap was flown on the National Aeronautics and Space Administration (NASA) Gulfstream GIII testbed at the NASA Armstrong Flight Research Center. This smoothly curving flap replaced the existing Fowler flaps creating a seamless control surface. This compliant structure, developed by FlexSys Inc. in partnership with the Air Force Research Laboratory, supported NASA objectives for airframe structural noise reduction, aerodynamic efficiency, and wing weight reduction through gust load alleviation. A thorough structures airworthiness approach was developed to move this project safely to flight. A combination of industry and NASA standard practice require various structural analyses, ground testing, and health monitoring techniques for showing an airworthy structure. This paper provides an overview of compliant structures design, the structural ground testing leading up to flight, and the flight envelope expansion and monitoring strategy. Flight data will be presented, and lessons learned along the way will be highlighted.

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

Energy Technology Data Exchange (ETDEWEB)

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

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. 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.

Flatland Photonics: Circumventing Diffraction with Planar Plasmonic Architectures

Science.gov (United States)

Dionne, Jennifer Anne

On subwavelength scales, photon-matter interactions are limited by diffraction. The diffraction limit restricts the size of optical devices and the resolution of conventional microscopes to wavelength-scale dimensions, severely hampering our ability to control and probe subwavelength-scale optical phenomena. Circumventing diffraction is now a principle focus of integrated nanophotonics. Surface plasmons provide a particularly promising approach to sub-diffraction-limited photonics. Surface plasmons are hybrid electron-photon modes confined to the interface between conductors and transparent materials. Combining the high localization of electronic waves with the propagation properties of optical waves, plasmons can achieve extremely small mode wavelengths and large local electromagnetic field intensities. Through their unique dispersion, surface plasmons provide access to an enormous phase space of refractive indices and propagation constants that can be readily tuned with material or geometry. In this thesis, we explore both the theory and applications of dispersion in planar plasmonic architectures. Particular attention is given to the modes of metallic core and plasmon slot waveguides, which can span positive, near-zero, and even negative indices. We demonstrate how such basic plasmonic geometries can be used to develop a suite of passive and active plasmonic components, including subwavelength waveguides, color filters, negative index metamaterials, and optical MOS field effect modulators. Positive index modes are probed by near- and far-field techniques, revealing plasmon wavelengths as small as one-tenth of the excitation wavelength. Negative index modes are characterized through direct visualization of negative refraction. By fabricating prisms comprised of gold, silicon nitride, and silver multilayers, we achieve the first experimental demonstration of a negative index material at visible frequencies, with potential applications for sub-diffraction

Submicron x-ray diffraction and its applications to problems in materials and environmental science

Science.gov (United States)

Tamura, N.; Celestre, R. S.; MacDowell, A. A.; Padmore, H. A.; Spolenak, R.; Valek, B. C.; Meier Chang, N.; Manceau, A.; Patel, J. R.

2002-03-01

The availability of high brilliance third generation synchrotron sources together with progress in achromatic focusing optics allows us to add submicron spatial resolution to the conventional century-old x-ray diffraction technique. The new capabilities include the possibility to map in situ, grain orientations, crystalline phase distribution, and full strain/stress tensors at a very local level, by combining white and monochromatic x-ray microbeam diffraction. This is particularly relevant for high technology industry where the understanding of material properties at a microstructural level becomes increasingly important. After describing the latest advances in the submicron x-ray diffraction techniques at the Advanced Light Source, we will give some examples of its application in material science for the measurement of strain/stress in metallic thin films and interconnects. Its use in the field of environmental science will also be discussed.

Submicron X-Ray Diffraction and its Applications to Problems in Materials and Environmental Science

Energy Technology Data Exchange (ETDEWEB)

Patel, J. R.

2002-08-16

The availability of high brilliance 3rd generation synchrotron sources together with progress in achromatic focusing optics allow to add submicron spatial resolution to the conventional century-old X-ray diffraction technique. The new capabilities include the possibility to map in-situ, grain orientations, crystalline phase distribution and full strain/stress tensors at a very local level, by combining white and monochromatic X-ray microbeam diffraction. This is particularly relevant for high technology industry where the understanding of material properties at a microstructural level becomes increasingly important. After describing the latest advances in the submicron X-ray diffraction techniques at the ALS, we will give some examples of its application in material science for the measurement of strain/stress in metallic thin films and interconnects. Its use in the field of environmental science will also be discussed.

Submicron X-ray diffraction and its applications to problems in materials and environmental science

Energy Technology Data Exchange (ETDEWEB)

Tamura, N.; Celestre, R.S.; MacDowell, A.A.; Padmore, H.A.; Spolenak, R.; Valek, B.C.; Meier Chang, N.; Manceau, A.; Patel, J.R.

2002-03-26

The availability of high brilliance 3rd generation synchrotron sources together with progress in achromatic focusing optics allow to add submicron spatial resolution to the conventional century-old X-ray diffraction technique. The new capabilities include the possibility to map in-situ, grain orientations, crystalline phase distribution and full strain/stress tensors at a very local level, by combining white and monochromatic X-ray microbeam diffraction. This is particularly relevant for high technology industry where the understanding of material properties at a microstructural level becomes increasingly important. After describing the latest advances in the submicron X-ray diffraction techniques at the ALS, we will give some examples of its application in material science for the measurement of strain/stress in metallic thin films and interconnects. Its use in the field of environmental science will also be discussed.

Application of combined multivariate techniques for the description of time-resolved powder X-ray diffraction data

Czech Academy of Sciences Publication Activity Database

Taris, A.; Grosso, M.; Brundu, M.; Guida, V.; Viani, Alberto

2017-01-01

Roč. 50, č. 2 (2017), s. 451-461 ISSN 1600-5767 R&D Projects: GA MŠk(CZ) LO1219 Keywords : in situ X-ray powder diffraction * amorphous content * chemically bonded ceramic s * statistical total correlation spectroscopy * multivariate curve resolution Subject RIV: JJ - Other Materials OBOR OECD: Materials engineering Impact factor: 2.495, year: 2016 http://journals.iucr.org/j/issues/2017/02/00/ap5006/index.html

Motion perception during tilt and translation after space flight

Science.gov (United States)

Clément, Gilles; Wood, Scott J.

2013-11-01

Preliminary results of an ongoing study examining the effects of space flight on astronauts' motion perception induced by independent tilt and translation motions are presented. This experiment used a sled and a variable radius centrifuge that translated the subjects forward-backward or laterally, and simultaneously tilted them in pitch or roll, respectively. Tests were performed on the ground prior to and immediately after landing. The astronauts were asked to report about their perceived motion in response to different combinations of body tilt and translation in darkness. Their ability to manually control their own orientation was also evaluated using a joystick with which they nulled out the perceived tilt while the sled and centrifuge were in motion. Preliminary results confirm that the magnitude of perceived tilt increased during static tilt in roll after space flight. A deterioration in the crewmember to control tilt using non-visual inertial cues was also observed post-flight. However, the use of a tactile prosthesis indicating the direction of down on the subject's trunk improved manual control performance both before and after space flight.

Effect of environmental temperature on diffraction efficiency for multilayer diffractive optical elements in Mid-wave infrared

Science.gov (United States)

Piao, Mingxu; Cui, Qingfeng; Zhu, Hao; Zhang, Bo

2014-11-01

In this paper, the effect of environmental temperature change on multilayer diffractive optical elements (MLDOEs) is evaluated from the viewpoint of the diffraction efficiency and the polychromatic integral diffraction efficiency (PIDE). As environmental temperature changes, the microstructure heights of MLDOEs expand or contract, and refractive indices of substrate materials also change. Based on the changes in microstructure height and substrate material index with environmental temperature, the theoretical relation between diffraction efficiency of MLDOEs and environmental temperature is deduced. A practical 3-5μm Mid-wave infrared (MWIR) optical system designed with a MLDOE, which made of ZNSE and GE, is discussed to illustrate the influence of environmental temperature change. The result shows that diffraction efficiency reduction is no more than 85% and PIDE reduction is less than 50% when environmental temperature ranges from -20°C to 60°C. According to the calculated diffraction efficiency in different environmental temperatures, the MTF of hybrid optical system is modified and the modified MTF curve is compared with the original MTF curve. Although the hybrid optical system achieved passive athermalization in above environmental temperature range, the modified MTF curve also remarkably decline in environmental temperature extremes after the consideration of diffraction efficiency change of MLDOE. It is indicated that the image quality of hybrid optical system with ZNSE-GE MLDOE is significantly sensitive to environmental temperature change. The analysis result can be used for optical engineering design with MLDOEs in MWIR.

Hard scattering and a diffractive trigger

International Nuclear Information System (INIS)

Berger, E.L.; Collins, J.C.; Soper, D.E.; Sterman, G.

1986-02-01

Conclusions concerning the properties of hard scattering in diffractively produced systems are summarized. One motivation for studying diffractive hard scattering is to investigate the interface between Regge theory and perturbative QCD. Another is to see whether diffractive triggering can result in an improvement in the signal-to-background ratio of measurements of production of very heavy quarks. 5 refs

A QCD analysis of ZEUS diffractive data

Energy Technology Data Exchange (ETDEWEB)

Chekanov, S.; Derrick, M.; Magill, S. [Argonne National Laboratory, Argonne, IL (US)] (and others)

2009-11-15

ZEUS inclusive diffractive cross-section measurements have been used in a DGLAP next-to-leading-order QCD analysis to extract the diffractive parton distribution functions. Data on diffractive dijet production in deep inelastic scattering have also been included to constrain the gluon density. Predictions based on the extracted parton densities are compared to diffractive charm and dijet photoproduction data. (orig.)

A QCD analysis of ZEUS diffractive data

International Nuclear Information System (INIS)

Chekanov, S.; Derrick, M.; Magill, S.

2009-11-01

ZEUS inclusive diffractive cross-section measurements have been used in a DGLAP next-to-leading-order QCD analysis to extract the diffractive parton distribution functions. Data on diffractive dijet production in deep inelastic scattering have also been included to constrain the gluon density. Predictions based on the extracted parton densities are compared to diffractive charm and dijet photoproduction data. (orig.)

miniPixD : a compact sample analysis system which combines X-ray imaging and diffraction

International Nuclear Information System (INIS)

Moss, Robert; Crews, Chiaki; Speller, Robert; Wilson, Matthew

2017-01-01

This paper introduces miniPixD : a new, compact system that utilises transmission X-ray imaging and X-ray diffraction (XRD) to locate and identify materials of interest within an otherwise opaque volume. The system and the embodied techniques have utility in security screening, medical diagnostics, non-destructive testing (NDT) and quality assurance (QA). This paper outlines the design of the system including discussion on the choice of components and presents some data from relevant samples which are compared to other energy dispersive and angular dispersive XRD techniques.

Diffraction of polarized light on periodic structures

International Nuclear Information System (INIS)

Bukanina, V; Divakov, D; Tyutyunnik, A; Hohlov, A

2012-01-01

Periodic structures as photonic crystals are widely used in modern laser devices, communication technologies and for creating various beam splitters and filters. Diffraction gratings are applied for creating 3D television sets, DVD and Blu-ray drives and reflective structures (Berkley mirror). It is important to simulate diffraction on such structures to design optical systems with predetermined properties based on photonic crystals and diffraction gratings. Methods of simulating diffraction on periodic structures uses theory of Floquet-Bloch and rigorous coupled-wave analysis (RCWA). Current work is dedicated to analysis of photonic band gaps and simulating diffraction on one-dimensional binary diffraction grating using RCWA. The Maxwell's equations for isotropic media and constitutive relations based on the cgs system were used as a model.

Diffraction enhanced x-ray imaging

International Nuclear Information System (INIS)

Thomlinson, W.; Zhong, Z.; Johnston, R.E.; Sayers, D.

1997-09-01

Diffraction enhanced imaging (DEI) is a new x-ray radiographic imaging modality using synchrotron x-rays which produces images of thick absorbing objects that are almost completely free of scatter. They show dramatically improved contrast over standard imaging applied to the same phantoms. The contrast is based not only on attenuation but also the refraction and diffraction properties of the sample. The diffraction component and the apparent absorption component (absorption plus extinction contrast) can each be determined independently. This imaging method may improve the image quality for medical applications such as mammography

Grazing incidence diffraction : A review

Energy Technology Data Exchange (ETDEWEB)

Gilles, B [LTPCM, ENSEEG. St. Martin d` Heres. (France)

1996-09-01

Different Grazing Incidence Diffraction (GID) methods for the analysis of thin films and multilayer structures are reviewed in three sections: the reflectivity is developed in the first one, which includes the non-specular diffuse scattering. The second one is devoted to the extremely asymmetric Bragg diffraction and the third one to the in-plane Bragg diffraction. Analytical formulations of the scattered intensities are developed for each geometry, in the framework of the kinetical analysis as well as the dynamical theory. Experimental examples are given to illustrate the quantitative possibility of the GID techniques.

Imaging Molecular Structure through Femtosecond Photoelectron Diffraction on Aligned and Oriented Gas-Phase Molecules

DEFF Research Database (Denmark)

Boll, Rebecca; Rouzee, Arnaud; Adolph, Marcus

2014-01-01

This paper gives an account of our progress towards performing femtosecond time-resolved photoelectron diffraction on gas-phase molecules in a pump-probe setup combining optical lasers and an X-ray Free-Electron Laser. We present results of two experiments aimed at measuring photoelectron angular...

Uniting Electron Crystallography and Powder Diffraction

CERN Document Server

Shankland, Kenneth; Meshi, Louisa; Avilov, Anatoly; David, William

2012-01-01

The polycrystalline and nanocrystalline states play an increasingly important role in exploiting the properties of materials, encompassing applications as diverse as pharmaceuticals, catalysts, solar cells and energy storage. A knowledge of the three-dimensional atomic and molecular structure of materials is essential for understanding and controlling their properties, yet traditional single-crystal X-ray diffraction methods lose their power when only polycrystalline and nanocrystalline samples are available. It is here that powder diffraction and single-crystal electron diffraction techniques take over, substantially extending the range of applicability of the crystallographic principles of structure determination.  This volume, a collection of teaching contributions presented at the Crystallographic Course in Erice in 2011, clearly describes the fundamentals and the state-of-the-art of powder diffraction and electron diffraction methods in materials characterisation, encompassing a diverse range of discipl...

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

Energy Technology Data Exchange (ETDEWEB)

Tsusaka, Y., E-mail: tsusaka@sci.u-hyogo.ac.jp; Takano, H. [Graduate School of Material Science, University of Hyogo, 3-2-1, Kouto, Kamigori, Hyogo 678-1297 (Japan); Takeda, S. [SPring-8 Service Co., Ltd., 1-20-5, Kouto, Shingu, Tatsuno, Hyogo 679-5165 (Japan); Yokoyama, K.; Matsui, J. [Synchrotron Radiation Nanotechnology Center, University of Hyogo, 1-490-2, Kouto, Shingu, Tatsuno, Hyogo 679-5165 (Japan); Kagoshima, Y. [Graduate School of Material Science, University of Hyogo, 3-2-1, Kouto, Kamigori, Hyogo 678-1297 (Japan); Synchrotron Radiation Nanotechnology Center, University of Hyogo, 1-490-2, Kouto, Shingu, Tatsuno, Hyogo 679-5165 (Japan)

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 of 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}.

Diffraction contrast imaging using virtual apertures

International Nuclear Information System (INIS)

Gammer, Christoph; Burak Ozdol, V.; Liebscher, Christian H.; Minor, Andrew M.

2015-01-01

Two methods on how to obtain the full diffraction information from a sample region and the associated reconstruction of images or diffraction patterns using virtual apertures are demonstrated. In a STEM-based approach, diffraction patterns are recorded for each beam position using a small probe convergence angle. Similarly, a tilt series of TEM dark-field images is acquired. The resulting datasets allow the reconstruction of either electron diffraction patterns, or bright-, dark- or annular dark-field images using virtual apertures. The experimental procedures of both methods are presented in the paper and are applied to a precipitation strengthened and creep deformed ferritic alloy with a complex microstructure. The reconstructed virtual images are compared with conventional TEM images. The major advantage is that arbitrarily shaped virtual apertures generated with image processing software can be designed without facing any physical limitations. In addition, any virtual detector that is specifically designed according to the underlying crystal structure can be created to optimize image contrast. - Highlights: • A dataset containing all structural information of a given position is recorded. • The dataset allows reconstruction of virtual diffraction patterns or images. • Specific virtual apertures are designed to image precipitates in a complex alloy. • Virtual diffraction patterns from arbitrarily small regions can be established. • Using STEM diffraction to record the dataset is more efficient than TEM dark-field

A hybrid flight control for a simulated raptor-30 v2 helicopter

International Nuclear Information System (INIS)

Khizer, A.N.

2015-01-01

This paper presents a hybrid flight control system for a single rotor simulated Raptor-30 V2 helicopter. Hybrid intelligent control system, combination of the conventional and intelligent control methodologies, is applied to small model helicopter. The proposed hybrid control used PID as a traditional control and fuzzy as an intelligent control so as to take the maximum advantage of advanced control theory. The helicopter model used; comes from X-Plane flight simulator and their hybrid flight control system was simulated using MATLAB/SIMULINK in a simulation platform. X-Plane is also used to visualize the performance of this proposed autopilot design. Through a series of numerous experiments, the operation of hybrid control system was investigated. Results verified that the proposed hybrid control has an excellent performance at hovering flight mode. (author)

Diffraction. Single crystal, magnetic

International Nuclear Information System (INIS)

Heger, G.

1999-01-01

The analysis of crystal structure and magnetic ordering is usually based on diffraction phenomena caused by the interaction of matter with X-rays, neutrons, or electrons. Complementary information is achieved due to the different character of X-rays, neutrons and electrons, and hence their different interactions with matter and further practical aspects. X-ray diffraction using conventional laboratory equipment and/or synchrotron installations is the most important method for structure analyses. The purpose of this paper is to discuss special cases, for which, in addition to this indispensable part, neutrons are required to solve structural problems. Even though the huge intensity of modern synchrotron sources allows in principle the study of magnetic X-ray scattering the investigation of magnetic structures is still one of the most important applications of neutron diffraction. (K.A.)

New Methodology for Optimal Flight Control using Differential Evolution Algorithms applied on the Cessna Citation X Business Aircraft – Part 2. Validation on Aircraft Research Flight Level D Simulator

Directory of Open Access Journals (Sweden)

Yamina BOUGHARI

2017-06-01

Full Text Available In this paper the Cessna Citation X clearance criteria were evaluated for a new Flight Controller. The Flight Control Law were optimized and designed for the Cessna Citation X flight envelope by combining the Deferential Evolution algorithm, the Linear Quadratic Regulator method, and the Proportional Integral controller during a previous research presented in part 1. The optimal controllers were used to reach satisfactory aircraft’s dynamic and safe flight operations with respect to the augmentation systems’ handling qualities, and design requirements. Furthermore the number of controllers used to control the aircraft in its flight envelope was optimized using the Linear Fractional Representations features. To validate the controller over the whole aircraft flight envelope, the linear stability, eigenvalue, and handling qualities criteria in addition of the nonlinear analysis criteria were investigated during this research to assess the business aircraft for flight control clearance and certification. The optimized gains provide a very good stability margins as the eigenvalue analysis shows that the aircraft has a high stability, and a very good flying qualities of the linear aircraft models are ensured in its entire flight envelope, its robustness is demonstrated with respect to uncertainties due to its mass and center of gravity variations.

A Survey of Open-Source UAV Flight Controllers and Flight Simulators

DEFF Research Database (Denmark)

Ebeid, Emad Samuel Malki; Skriver, Martin; Terkildsen, Kristian Husum

2018-01-01

, which are all tightly linked to the UAV flight controller hardware and software. The lack of standardization of flight controller architectures and the use of proprietary closed-source flight controllers on many UAV platforms, however, complicates this work: solutions developed for one flight controller...... may be difficult to port to another without substantial extra development and testing. Using open-source flight controllers mitigates some of these challenges and enables other researchers to validate and build upon existing research. This paper presents a survey of the publicly available open...

The role of situation assessment and flight experience in pilots' decisions to continue visual flight rules flight into adverse weather.

Science.gov (United States)

Wiegmann, Douglas A; Goh, Juliana; O'Hare, David

2002-01-01

Visual flight rules (VFR) flight into instrument meteorological conditions (IMC) is a major safety hazard in general aviation. In this study we examined pilots' decisions to continue or divert from a VFR flight into IMC during a dynamic simulation of a cross-country flight. Pilots encountered IMC either early or later into the flight, and the amount of time and distance pilots flew into the adverse weather prior to diverting was recorded. Results revealed that pilots who encountered the deteriorating weather earlier in the flight flew longer into the weather prior to diverting and had more optimistic estimates of weather conditions than did pilots who encountered the deteriorating weather later in the flight. Both the time and distance traveled into the weather prior to diverting were negatively correlated with pilots' previous flight experience. These findings suggest that VFR flight into IMC may be attributable, at least in part, to poor situation assessment and experience rather than to motivational judgment that induces risk-taking behavior as more time and effort are invested in a flight. Actual or potential applications of this research include the design of interventions that focus on improving weather evaluation skills in addition to addressing risk-taking attitudes.

Theseus in Flight

Science.gov (United States)

1996-01-01

The twin pusher propeller-driven engines of the Theseus research aircraft can be clearly seen in this photo, taken during a 1996 research flight at NASA's Dryden Flight Research Center, Edwards, California. The Theseus aircraft, built and operated by Aurora Flight Sciences Corporation, Manassas, Virginia, was a unique aircraft flown at NASA's Dryden Flight Research Center, Edwards, California, under a cooperative agreement between NASA and Aurora. Dryden hosted the Theseus program, providing hangar space and range safety for flight testing. Aurora Flight Sciences was responsible for the actual flight testing, vehicle flight safety, and operation of the aircraft. The Theseus remotely piloted aircraft flew its maiden flight on May 24, 1996, at Dryden. During its sixth flight on November 12, 1996, Theseus experienced an in-flight structural failure that resulted in the loss of the aircraft. As of the beginning of the year 2000, Aurora had not rebuilt the aircraft. Theseus was built for NASA under an innovative, $4.9 million fixed-price contract by Aurora Flight Sciences Corporation and its partners, West Virginia University, Morgantown, West Virginia, and Fairmont State College, Fairmont, West Virginia. The twin-engine, unpiloted vehicle had a 140-foot wingspan, and was constructed largely of composite materials. Powered by two 80-horsepower, turbocharged piston engines that drove twin 9-foot-diameter propellers, Theseus was designed to fly autonomously at high altitudes, with takeoff and landing under the active control of a ground-based pilot in a ground control station 'cockpit.' With the potential ability to carry 700 pounds of science instruments to altitudes above 60,000 feet for durations of greater than 24 hours, Theseus was intended to support research in areas such as stratospheric ozone depletion and the atmospheric effects of future high-speed civil transport aircraft engines. Instruments carried aboard Theseus also would be able to validate satellite

Microgravity Flight: Accommodating Non-Human Primates

Science.gov (United States)

Dalton, Bonnie P.; Searby, Nancy; Ostrach, Louis

1995-01-01

Spacelab Life Sciences-3 (SLS-3) was scheduled to be the first United States man-tended microgravity flight containing Rhesus monkeys. The goal of this flight as in the five untended Russian COSMOS Bion flights and an earlier American Biosatellite flight, was to understand the biomedical and biological effects of a microgravity environment using the non-human primate as human surrogate. The SLS-3/Rhesus Project and COSMOS Primate-BIOS flights all utilized the rhesus monkey, Macaca mulatta. The ultimate objective of all flights with an animal surrogate has been to evaluate and understand biological mechanisms at both the system and cellular level, thus enabling rational effective countermeasures for future long duration human activity under microgravity conditions and enabling technical application to correction of common human physiological problems within earth's gravity, e.g., muscle strength and reloading, osteoporosis, immune deficiency diseases. Hardware developed for the SLS-3/Rhesus Project was the result of a joint effort with the French Centre National d'Etudes Spatiales (CNES) and the United States National Aeronautics and Space Administration (NASA) extending over the last decade. The flight hardware design and development required implementation of sufficient automation to insure flight crew and animal bio-isolation and maintenance with minimal impact to crew activities. A variety of hardware of varying functional capabilities was developed to support the scientific objectives of the original 22 combined French and American experiments, along with 5 Russian co-investigations, including musculoskeletal, metabolic, and behavioral studies. Unique elements of the Rhesus Research Facility (RRF) included separation of waste for daily delivery of urine and fecal samples for metabolic studies and a psychomotor test system for behavioral studies along with monitored food measurement. As in untended flights, telemetry measurements would allow monitoring of

A Simple Flight Mill for the Study of Tethered Flight in Insects.

Science.gov (United States)

Attisano, Alfredo; Murphy, James T; Vickers, Andrew; Moore, Patricia J

2015-12-10

Flight in insects can be long-range migratory flights, intermediate-range dispersal flights, or short-range host-seeking flights. Previous studies have shown that flight mills are valuable tools for the experimental study of insect flight behavior, allowing researchers to examine how factors such as age, host plants, or population source can influence an insects' propensity to disperse. Flight mills allow researchers to measure components of flight such as speed and distance flown. Lack of detailed information about how to build such a device can make their construction appear to be prohibitively complex. We present a simple and relatively inexpensive flight mill for the study of tethered flight in insects. Experimental insects can be tethered with non-toxic adhesives and revolve around an axis by means of a very low friction magnetic bearing. The mill is designed for the study of flight in controlled conditions as it can be used inside an incubator or environmental chamber. The strongest points are the very simple electronic circuitry, the design that allows sixteen insects to fly simultaneously allowing the collection and analysis of a large number of samples in a short time and the potential to use the device in a very limited workspace. This design is extremely flexible, and we have adjusted the mill to accommodate different species of insects of various sizes.

Tomography with energy dispersive diffraction

Science.gov (United States)

Stock, S. R.; Okasinski, J. S.; Woods, R.; Baldwin, J.; Madden, T.; Quaranta, O.; Rumaiz, A.; Kuczewski, T.; Mead, J.; Krings, T.; Siddons, P.; Miceli, A.; Almer, J. D.

2017-09-01

X-ray diffraction can be used as the signal for tomographic reconstruction and provides a cross-sectional map of the crystallographic phases and related quantities. Diffraction tomography has been developed over the last decade using monochromatic x-radiation and an area detector. This paper reports tomographic reconstruction with polychromatic radiation and an energy sensitive detector array. The energy dispersive diffraction (EDD) geometry, the instrumentation and the reconstruction process are described and related to the expected resolution. Results of EDD tomography are presented for two samples containing hydroxyapatite (hAp). The first is a 3D-printed sample with an elliptical crosssection and contains synthetic hAp. The second is a human second metacarpal bone from the Roman-era cemetery at Ancaster, UK and contains bio-hAp which may have been altered by diagenesis. Reconstructions with different diffraction peaks are compared. Prospects for future EDD tomography are also discussed.

Digital diffractive optics: Have diffractive optics entered mainstream industry yet?

Science.gov (United States)

Kress, Bernard; Hejmadi, Vic

2010-05-01

When a new technology is integrated into industry commodity products and consumer electronic devices, and sold worldwide in retail stores, it is usually understood that this technology has then entered the realm of mainstream technology and therefore mainstream industry. Such a leap however does not come cheap, as it has a double edge sword effect: first it becomes democratized and thus massively developed by numerous companies for various applications, but also it becomes a commodity, and thus gets under tremendous pressure to cut down its production and integration costs while not sacrificing to performance. We will show, based on numerous examples extracted from recent industry history, that the field of Diffractive Optics is about to undergo such a major transformation. Such a move has many impacts on all facets of digital diffractive optics technology, from the optical design houses to the micro-optics foundries (for both mastering and volume replication), to the final product integrators or contract manufacturers. The main causes of such a transformation are, as they have been for many other technologies in industry, successive technological bubbles which have carried and lifted up diffractive optics technology within the last decades. These various technological bubbles have been triggered either by real industry needs or by virtual investment hype. Both of these causes will be discussed in the paper. The adjective ""digital"" in "digital diffractive optics" does not refer only, as it is done in digital electronics, to the digital functionality of the element (digital signal processing), but rather to the digital way they are designed (by a digital computer) and fabricated (as wafer level optics using digital masking techniques). However, we can still trace a very strong similarity between the emergence of micro-electronics from analog electronics half a century ago, and the emergence of digital optics from conventional optics today.

Computer Simulation of Diffraction Patterns.

Science.gov (United States)

Dodd, N. A.

1983-01-01

Describes an Apple computer program (listing available from author) which simulates Fraunhofer and Fresnel diffraction using vector addition techniques (vector chaining) and allows user to experiment with different shaped multiple apertures. Graphics output include vector resultants, phase difference, diffraction patterns, and the Cornu spiral…

Diffraction limit of refractive compound lens

International Nuclear Information System (INIS)

Kolchevsky, N.N.; Petrov, P.V.

2015-01-01

A compound X-ray and neutron lenses is an array of lenses with a common axis. The resolution limited by aberration and by diffraction. Diffraction limit comes from theory based on absorption aperture of the compound refractive lenses. Beam passing through transparent lenses form Airy pattern. Results of calculation of diffraction resolution limit for non-transparent X-ray and neutron lenses are discussed. (authors)

Bat flight: aerodynamics, kinematics and flight morphology.

Science.gov (United States)

Hedenström, Anders; Johansson, L Christoffer

2015-03-01

Bats evolved the ability of powered flight more than 50 million years ago. The modern bat is an efficient flyer and recent research on bat flight has revealed many intriguing facts. By using particle image velocimetry to visualize wake vortices, both the magnitude and time-history of aerodynamic forces can be estimated. At most speeds the downstroke generates both lift and thrust, whereas the function of the upstroke changes with forward flight speed. At hovering and slow speed bats use a leading edge vortex to enhance the lift beyond that allowed by steady aerodynamics and an inverted wing during the upstroke to further aid weight support. The bat wing and its skeleton exhibit many features and control mechanisms that are presumed to improve flight performance. Whereas bats appear aerodynamically less efficient than birds when it comes to cruising flight, they have the edge over birds when it comes to manoeuvring. There is a direct relationship between kinematics and the aerodynamic performance, but there is still a lack of knowledge about how (and if) the bat controls the movements and shape (planform and camber) of the wing. Considering the relatively few bat species whose aerodynamic tracks have been characterized, there is scope for new discoveries and a need to study species representing more extreme positions in the bat morphospace. © 2015. Published by The Company of Biologists Ltd.

Deep-inelastic electron-proton diffraction

International Nuclear Information System (INIS)

Dainton, J.B.

1995-11-01

Recent measurements by the H1 collaboration at HERA of the cross section for deep-inelastic electron-proton scattering in which the proton interacts with minimal energy transfer and limited 4-momentum transfer squared are presented in the form of the contribution F 2 D(3) to the proton structure function F 2 . By parametrising the cross section phenomenologically in terms of a leading effective Regge pole exchange and comparing the result with a similar parametrisation of hadronic pp physics, the proton interaction is demonstrated to be dominantly of a diffractive nature. The quantitative interpretation of the parametrisation in terms of the properties of an effective leading Regge pole exchange, the pomeron (IP), shows that there is no evidence for a 'harder' BFKL-motivated IP in such deep-inelastic proton diffraction. The total contribution of proton diffraction to deep-inelastic electron-proton scattering is measured to be ∝10% and to be rather insensitive to Bjorken-x and Q 2 . A first measurement of the partonic structure of diffractive exchange is presented. It is shown to be readily interpreted in terms of the exchange of gluons, and to suggest that the bulk of diffractive momentum transfer is carried by a leading gluon. (orig.)

HIAD on ULA (HULA) Orbital Reentry Flight Experiment Concept

Science.gov (United States)

Dinonno, J. M.; Cheatwood, F. M.; Hughes, S. J.; Ragab, M. M.; Dillman, R. A.; Bodkin, R. J.; Zumwalt, C. H.; Johnson, R. K.

2016-01-01

This paper describes a proposed orbital velocity reentry flight test of a Hypersonic Inflatable Aerodynamic Decelerator (HIAD). The flight test builds upon ground development activities that continue to advance the materials, design, and manufacturing techniques for the inflatable structure and flexible thermal protection system (F-TPS) that comprise the inflatable heat shield. While certain aspects of material and system performance can be assessed using a variety of ground testing capabilities, only orbital velocity energy on a trajectory through the gradient density of the atmosphere can impart the combined aerodynamic and aeroheating design environments in real time. To achieve this at limited cost, the HIAD would be delivered to a spin-stabilized entry trajectory as a secondary payload on the Centaur stage of a United Launch Alliance (ULA) Atlas V launch vehicle. Initial trajectory studies indicate that the combination of launch vehicle capability and achievable reentry vehicle ballistic numbers make this a strategic opportunity for technology development. This 4 to 6 meter diameter scale aeroshell flight, referred to as HIAD on ULA (HULA), would also contribute to ULA asset recovery development. ULA has proposed that a HIAD be utilized as part of the Sensible, Modular, Autonomous Return Technology (SMART) initiative to enable recovery of the Vulcan launch vehicle booster main engines [1], including a Mid-Air Recovery (MAR) to gently return these assets for reuse. Whereas HULA will attain valuable aerothermal and structural response data toward advancing HIAD technology, it may also provide a largest-to-date scaled flight test of the MAR operation, which in turn would allow the examination of a nearly pristine post-entry aeroshell. By utilizing infrared camera imaging, HULA will also attain aft-side thermal response data, enhancing understanding of the aft side aerothermal environment, an area of high uncertainty. The aeroshell inflation will utilize a

Selected Flight Test Results for Online Learning Neural Network-Based Flight Control System

Science.gov (United States)

Williams-Hayes, Peggy S.

2004-01-01

The NASA F-15 Intelligent Flight Control System project team developed a series of flight control concepts designed to demonstrate neural network-based adaptive controller benefits, with the objective to develop and flight-test control systems using neural network technology to optimize aircraft performance under nominal conditions and stabilize the aircraft under failure conditions. This report presents flight-test results for an adaptive controller using stability and control derivative values from an online learning neural network. A dynamic cell structure neural network is used in conjunction with a real-time parameter identification algorithm to estimate aerodynamic stability and control derivative increments to baseline aerodynamic derivatives in flight. This open-loop flight test set was performed in preparation for a future phase in which the learning neural network and parameter identification algorithm output would provide the flight controller with aerodynamic stability and control derivative updates in near real time. Two flight maneuvers are analyzed - pitch frequency sweep and automated flight-test maneuver designed to optimally excite the parameter identification algorithm in all axes. Frequency responses generated from flight data are compared to those obtained from nonlinear simulation runs. Flight data examination shows that addition of flight-identified aerodynamic derivative increments into the simulation improved aircraft pitch handling qualities.

Refractive and diffractive neutron optics with reduced chromatic aberration

Energy Technology Data Exchange (ETDEWEB)

Poulsen, S.O., E-mail: stefan.poulsen@northwestern.edu [NEXMAP, Department of Physics, Technical University of Denmark, Anker Engelunds Vej 1, 2800 Kgs. Lyngby (Denmark); Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208 (United States); Poulsen, H.F. [NEXMAP, Department of Physics, Technical University of Denmark, Anker Engelunds Vej 1, 2800 Kgs. Lyngby (Denmark); Bentley, P.M. [European Spallation Source ESS AB, Box 176, 221 00 Lund (Sweden)

2014-12-11

Thermal neutron beams are an indispensable tool in physics research. The spatial and the temporal resolution attainable in experiments are dependent on the flux and collimation of the neutron beam which remain relatively poor, even for modern neutron sources. These difficulties may be mitigated by the use of optics for focusing and imaging. Refractive and diffractive optical elements, e.g. compound refractive lenses and Fresnel zone plates, are attractive due to their low cost, and simple alignment. These optical elements, however, suffer from chromatic aberration, which limit their effectiveness to highly monochromatic beams. This paper presents two novel concepts for focusing and imaging non-monochromatic thermal neutron beams with well-known optical elements: (1) a fast mechanical transfocator based on a compound refractive lens, which actively varies the number of individual lenses in the beam path to focus and image a time-of-flight beam, and (2) a passive optical element consisting of a compound refractive lens, and a Fresnel zone plate, which may focus and image both continuous and pulsed neutron beams.

X-ray diffraction imaging of material microstructures

KAUST Repository

Varga, Laszlo

2016-10-20

Various examples are provided for x-ray imaging of the microstructure of materials. In one example, a system for non-destructive material testing includes an x-ray source configured to generate a beam spot on a test item; a grid detector configured to receive x- rays diffracted from the test object; and a computing device configured to determine a microstructure image based at least in part upon a diffraction pattern of the x-rays diffracted from the test object. In another example, a method for determining a microstructure of a material includes illuminating a beam spot on the material with a beam of incident x-rays; detecting, with a grid detector, x-rays diffracted from the material; and determining, by a computing device, a microstructure image based at least in part upon a diffraction pattern of the x-rays diffracted from the material.

14 CFR 121.412 - Qualifications: Flight instructors (airplane) and flight instructors (simulator).

Science.gov (United States)

2010-01-01

... (airplane) and flight instructors (simulator). 121.412 Section 121.412 Aeronautics and Space FEDERAL... OPERATIONS Training Program § 121.412 Qualifications: Flight instructors (airplane) and flight instructors (simulator). (a) For the purposes of this section and § 121.414: (1) A flight instructor (airplane) is a...

Inclusive transverse momentum distributions of charged particles in diffractive and non-diffractive photoproduction at HERA

International Nuclear Information System (INIS)

Derrick, M.; Krakauer, D.; Magill, S.

1995-03-01

Inclusive transverse momentum spectra of charged particles in photoproduction events in the laboratory pseudorapidity range -1.2 T =8 GeV using the ZEUS detector. Diffractive and non-diffractive reactions have been selected with an average γp centre of mass (c.m.) energy of =180 GeV. For diffractive reactions, the p T spectra of the photon dissociation events have been measured in two intervals of the dissociated photon mass with mean values X >=5 GeV and 10 GeV. The inclusive transverse momentum spectra fall exponentially in the low p T region. The non-diffractive data show a pronounced high p T tail departing from the exponential shape. The p T distributions are compared to lower energy photoproduction data and to hadron-hadron collisions at a similar c.m. energy. The data are also compared to the results of a next-to-leading order QCD calculation. (orig.)

The ALICE Time of Flight Readout System AFRO

CERN Document Server

Kluge, A

1999-01-01

The ALICE Time of Flight Detector system comprises more than 100.000 channels and covers an area of more than 100 m2. The timing resolution should be better than 150 ps. This combination of requirements poses a major challenge to the readout system. All detector timing measurements are referenced to a unique start signal t0. This signal is generated at the time an event occurs. Timing measurements are performed using a multichannel TDC chip which requires a 40 MHz reference clock signal. The general concept of the readout system is based on a modular architecture. Detector cells are combined to modules of 1024 channels. Each of these modules can be read out and calibrated independently from each other. By distributing a reference signal, a timing relationship between the modules is established. This reference signal can either be the start signal t0 or the TDC-reference clock. The readout architecture is divided into three steps; the TDC controller, the module controller, and the time of flight controller. Th...

Overview of Pre-Flight Physical Training, In-Flight Exercise Countermeasures and the Post-Flight Reconditioning Program for International Space Station Astronauts

Science.gov (United States)

Kerstman, Eric

2011-01-01

International Space Station (ISS) astronauts receive supervised physical training pre-flight, utilize exercise countermeasures in-flight, and participate in a structured reconditioning program post-flight. Despite recent advances in exercise hardware and prescribed exercise countermeasures, ISS crewmembers are still found to have variable levels of deconditioning post-flight. This presentation provides an overview of the astronaut medical certification requirements, pre-flight physical training, in-flight exercise countermeasures, and the post-flight reconditioning program. Astronauts must meet medical certification requirements on selection, annually, and prior to ISS missions. In addition, extensive physical fitness testing and standardized medical assessments are performed on long duration crewmembers pre-flight. Limited physical fitness assessments and medical examinations are performed in-flight to develop exercise countermeasure prescriptions, ensure that the crewmembers are physically capable of performing mission tasks, and monitor astronaut health. Upon mission completion, long duration astronauts must re-adapt to the 1 G environment, and be certified as fit to return to space flight training and active duty. A structured, supervised postflight reconditioning program has been developed to prevent injuries, facilitate re-adaptation to the 1 G environment, and subsequently return astronauts to training and space flight. The NASA reconditioning program is implemented by the Astronaut Strength, Conditioning, and Rehabilitation (ASCR) team and supervised by NASA flight surgeons. This program has evolved over the past 10 years of the International Space Station (ISS) program and has been successful in ensuring that long duration astronauts safely re-adapt to the 1 g environment and return to active duty. Lessons learned from this approach to managing deconditioning can be applied to terrestrial medicine and future exploration space flight missions.

Quantitative phase analysis by neutron diffraction

Energy Technology Data Exchange (ETDEWEB)

Lee, Chang Hee; Song, Su Ho; Lee, Jin Ho; Shim, Hae Seop [Korea Atomic Energy Research Institute, Taejon (Korea)

1999-06-01

This study is to apply quantitative phase analysis (QPA) by neutron diffraction to the round robin samples provided by the International Union of Crystallography(IUCr). We measured neutron diffraction patterns for mixed samples which have several different weight percentages and their unique characteristic features. Neutron diffraction method has been known to be superior to its complementary methods such as X-ray or Synchrotron, but it is still accepted as highly reliable under limited conditions or samples. Neutron diffraction has strong capability especially on oxides due to its scattering cross-section of the oxygen and it can become a more strong tool for analysis on the industrial materials with this quantitative phase analysis techniques. By doing this study, we hope not only to do one of instrument performance tests on our HRPD but also to improve our ability on the analysis of neutron diffraction data by comparing our QPA results with others from any advanced reactor facilities. 14 refs., 4 figs., 6 tabs. (Author)

Nonlinear diffraction from a virtual beam

DEFF Research Database (Denmark)

Saltiel, Solomon M.; Neshev, Dragomir N.; Krolikowski, Wieslaw

2010-01-01

We observe experimentally a novel type of nonlinear diffraction in the process of two-wave mixing on a nonlinear quadratic grating.We demonstrate that when the nonlinear grating is illuminated simultaneously by two noncollinear beams, a second-harmonic diffraction pattern is generated by a virtual...... beam propagating along the bisector of the two pump beams. The observed iffraction phenomena is a purely nonlinear effect that has no analogue in linear diffraction...

Theory of edge diffraction in electromagnetics

CERN Document Server

Ufimtsev, Pyotr

2009-01-01

This book is an essential resource for researchers involved in designing antennas and RCS calculations. It is also useful for students studying high frequency diffraction techniques. It contains basic original ideas of the Physical Theory of Diffraction (PTD), examples of its practical application, and its validation by the mathematical theory of diffraction. The derived analytic expressions are convenient for numerical calculations and clearly illustrate the physical structure of the scattered field.

X-ray diffraction measurements to determine longitudinal and transverse lattice deformation in shocked LiF

International Nuclear Information System (INIS)

Rigg, P.A.; Gupta, Y.M.

2000-01-01

Experimental methods using both single and multiple x-ray diffraction were developed to determine real time, lattice deformation in directions parallel and perpendicular to shock wave propagation in single crystals subjected to plate impact loading. Initial experiments used single diffraction to monitor the interplanar spacing change, parallel to the shock propagation direction, in LiF crystals shocked along the [111] and [100] directions. These measurements, in combination with the macroscopic volume compression, were used to determine the state of compression of the unit cell. Subsequent development of a multiple diffraction technique permitted simultaneous determination of both the longitudinal and transverse lattice deformations. The present results showed that shock compression, below 4 GPa, along the [111] orientation--which results in macroscopic elastic deformation - produced one-dimensional unit cell compression. In contrast, shock compression along the [100] orientation - which results in macroscopic elastic-plastic deformation--produced isotropic unit cell compression. The implications of the present results and the ability to make quantitative x-ray diffraction measurements under shock loading are discussed

New structural studies of liquid crystal by reflectivity and resonant X-ray diffraction

International Nuclear Information System (INIS)

Fernandes, P.

2007-04-01

This memory presents three structural studies of smectic Liquid Crystals by reflectivity and resonant diffraction of X-rays. It is divided in five chapters. In the first a short introduction to Liquid Crystals is given. In particular, the smectic phases that are the object of this study are presented. The second chapter is consecrated to the X-ray experimental techniques that were used in this work. The three last chapters present the works on which this thesis can be divided. Chapter three demonstrates on free-standing films of MHPOBC (historic liquid crystal that possesses the antiferroelectric sub-phases) the possibility to extend the technique of resonant X-ray diffraction to liquid crystals without resonant element. In the fourth chapter the structure of the B 2 liquid crystal phase of bent-core molecules (or banana molecules) is elucidated by using resonant X-ray diffraction combined with polarization analysis of the diffracted beam. A model of the polarization of the resonant beam diffracted by four different structures proposed for the B 2 phase is developed in this chapter. In the fifth chapter a smectic binary mixture presenting a very original critical point of phase separation is studied by X-ray reflectivity and optical microscopy. A concentration gradient in the direction perpendicular to the plane of the film seems to be induced by the free-standing film geometry. The results of a simplified model of the system are compatible with this interpretation

Immobilization of biomolecules onto surfaces according to ultraviolet light diffraction patterns

International Nuclear Information System (INIS)

Bjoern Petersen, Steffen; Kold di Gennaro, Ane; Neves-Petersen, Maria Teresa; Skovsen, Esben; Parracino, Antonietta

2010-01-01

We developed a method for immobilization of biomolecules onto thiol functionalized surfaces according to UV diffraction patterns. UV light-assisted molecular immobilization proceeds through the formation of free, reactive thiol groups that can bind covalently to thiol reactive surfaces. We demonstrate that, by shaping the pattern of the UV light used to induce molecular immobilization, one can control the pattern of immobilized molecules onto the surface. Using a single-aperture spatial mask, combined with the Fourier transforming property of a focusing lens, we show that submicrometer (0.7 μm) resolved patterns of immobilized prostate-specific antigen biomolecules can be created. If a dual-aperture spatial mask is used, the results differ from the expected Fourier transform pattern of the mask. It appears as a superposition of two diffraction patterns produced by the two apertures, with a fine structured interference pattern superimposed.

Advanced aircraft service life monitoring method via flight-by-flight load spectra

Science.gov (United States)

Lee, Hongchul

This research is an effort to understand current method and to propose an advanced method for Damage Tolerance Analysis (DTA) for the purpose of monitoring the aircraft service life. As one of tasks in the DTA, the current indirect Individual Aircraft Tracking (IAT) method for the F-16C/D Block 32 does not properly represent changes in flight usage severity affecting structural fatigue life. Therefore, an advanced aircraft service life monitoring method based on flight-by-flight load spectra is proposed and recommended for IAT program to track consumed fatigue life as an alternative to the current method which is based on the crack severity index (CSI) value. Damage Tolerance is one of aircraft design philosophies to ensure that aging aircrafts satisfy structural reliability in terms of fatigue failures throughout their service periods. IAT program, one of the most important tasks of DTA, is able to track potential structural crack growth at critical areas in the major airframe structural components of individual aircraft. The F-16C/D aircraft is equipped with a flight data recorder to monitor flight usage and provide the data to support structural load analysis. However, limited memory of flight data recorder allows user to monitor individual aircraft fatigue usage in terms of only the vertical inertia (NzW) data for calculating Crack Severity Index (CSI) value which defines the relative maneuver severity. Current IAT method for the F-16C/D Block 32 based on CSI value calculated from NzW is shown to be not accurate enough to monitor individual aircraft fatigue usage due to several problems. The proposed advanced aircraft service life monitoring method based on flight-by-flight load spectra is recommended as an improved method for the F-16C/D Block 32 aircraft. Flight-by-flight load spectra was generated from downloaded Crash Survival Flight Data Recorder (CSFDR) data by calculating loads for each time hack in selected flight data utilizing loads equations. From

The logarithmic slope in diffractive DIS

International Nuclear Information System (INIS)

Gay Ducati, M.B.; Goncalves, V.P.; Machado, M.V.T.

2002-01-01

The logarithmic slope of diffractive structure function is a potential observable to separate the hard and soft contributions in diffraction, allowing to disentangle the QCD dynamics at small-x region. In this paper we extend our previous analyzes and calculate the diffractive logarithmic slope for three current approaches in the literature: (i) the Bartels-Wusthoff model, based on perturbative QCD, (ii) the CKMT model, based on Regge theory and (iii) the Golec-Biernat-Wusthoff model which assumes that the saturation phenomena is present in the HERA kinematic region. We analyze the transition region of small to large momentum transfer and verify that future experimental results on the diffractive logarithmic slope could discriminate between these approaches

Fabrication of the polarization independent spectral beam combining grating

Science.gov (United States)

Liu, Quan; Jin, Yunxia; Wu, Jianhong; Guo, Peiliang

2016-03-01

Owing to damage, thermal issues, and nonlinear optical effects, the output power of fiber laser has been proven to be limited. Beam combining techniques are the attractive solutions to achieve high-power high-brightness fiber laser output. The spectral beam combining (SBC) is a promising method to achieve high average power output without influencing the beam quality. A polarization independent spectral beam combining grating is one of the key elements in the SBC. In this paper the diffraction efficiency of the grating is investigated by rigorous coupled-wave analysis (RCWA). The theoretical -1st order diffraction efficiency of the grating is more than 95% from 1010nm to 1080nm for both TE and TM polarizations. The fabrication tolerance is analyzed. The polarization independent spectral beam combining grating with the period of 1.04μm has been fabricated by holographic lithography - ion beam etching, which are within the fabrication tolerance.

Neutron diffraction utilizing the T-O-F method

Energy Technology Data Exchange (ETDEWEB)

Niimura, N [Tohoku Univ., Sendai (Japan). Lab. of Nuclear Science

1974-12-01

Characteristic features of the TOF (time of flight) neutron diffraction are summarized. In this method, i) all the reciprocal points on the rod passing through the origin in the reciprocal space can be scanned by each burst of white neutrons, ii) it is easy to measure high index reflections at the large scattering angle, iii) each reflection is not affected by the higher-order harmonics, and iv) it is easy to measure the physical properties depending on the neutron wavelength. The pulse neutron generator as well as the data acquisition system in the Laboratory of Nuclear Science of Tohoku University is described. The TOF method seems to be very powerful if it is applied to accurate structure analysis. The data correction methods are discussed. The TOF method is prospective to the study of transient phenomena. In this method one can apply to the crystalline sample an external field pulsed with the same frequency as the neutrons. By using this method, the transient state of the polarization reversal of the ferroelectric NaNO/sub 2/ has been observed. The magnetically pulsed neutron TOF spectrometer is briefly introduced after a review of the chopper history.

High Resolution Powder Diffraction and Structure Determination

International Nuclear Information System (INIS)

Cox, D. E.

1999-01-01

It is clear that high-resolution synchrotrons X-ray powder diffraction is a very powerful and convenient tool for material characterization and structure determination. Most investigations to date have been carried out under ambient conditions and have focused on structure solution and refinement. The application of high-resolution techniques to increasingly complex structures will certainly represent an important part of future studies, and it has been seen how ab initio solution of structures with perhaps 100 atoms in the asymmetric unit is within the realms of possibility. However, the ease with which temperature-dependence measurements can be made combined with improvements in the technology of position-sensitive detectors will undoubtedly stimulate precise in situ structural studies of phase transitions and related phenomena. One challenge in this area will be to develop high-resolution techniques for ultra-high pressure investigations in diamond anvil cells. This will require highly focused beams and very precise collimation in front of the cell down to dimensions of 50 (micro)m or less. Anomalous scattering offers many interesting possibilities as well. As a means of enhancing scattering contrast it has applications not only to the determination of cation distribution in mixed systems such as the superconducting oxides discussed in Section 9.5.3, but also to the location of specific cations in partially occupied sites, such as the extra-framework positions in zeolites, for example. Another possible application is to provide phasing information for ab initio structure solution. Finally, the precise determination of f as a function of energy through an absorption edge can provide useful information about cation oxidation states, particularly in conjunction with XANES data. In contrast to many experiments at a synchrotron facility, powder diffraction is a relatively simple and user-friendly technique, and most of the procedures and software for data analysis

A neutron time-of-flight data acquisition system

International Nuclear Information System (INIS)

Morris, D.V.

1983-10-01

A neutron time-of-flight scaler system is described for use with the Harwell Linac. The equipment is sufficiently versatile to be used with several types of computers although normally used with DEC PDP 11/45 and PDP 11/34. Using a combination of different input and memory boards most types of experiments can be accommodated. (author)

Calculated efficiencies of three-material low stress coatings for diffractive x-ray transmission optics

International Nuclear Information System (INIS)

Kubec, Adam; Braun, Stefan; Gawlitza, Peter; Menzel, Maik; Leson, Andreas

2016-01-01

Diffractive X-ray optical elements made by thin film coating techniques such as multilayer Laue lenses (MLL) and multilayer zone plates (MZP) are promising approaches to achieve resolutions in hard X-ray microscopy applications of less than 10 nm. The challenge is to make a lens with a large numerical aperture on the one hand and a decent working distance on the other hand. One of the limiting factors with the coated structures is the internal stress in the films, which can lead to significant bending of the substrate and various types of unwanted diffraction effects. Several approaches have been discussed to overcome this challenge. One of these is a three-material combination such as Mo/MoSi_2/Si, where four single layers per period are deposited. Mo and Si represent the absorber and spacer in this case while MoSi_2 forms a diffusion barrier; in addition the thicknesses of absorber and spacer are chosen to minimize residual stress of the overall coating. Here the diffraction efficiency as well as the profile of the beam in the focal plane are discussed in order to find a tradeoff between lowest residual stress and best diffraction properties.

Advanced Transport Operating System (ATOPS) Flight Management/Flight Controls (FM/FC) software description

Science.gov (United States)

Wolverton, David A.; Dickson, Richard W.; Clinedinst, Winston C.; Slominski, Christopher J.

1993-01-01

The flight software developed for the Flight Management/Flight Controls (FM/FC) MicroVAX computer used on the Transport Systems Research Vehicle for Advanced Transport Operating Systems (ATOPS) research is described. The FM/FC software computes navigation position estimates, guidance commands, and those commands issued to the control surfaces to direct the aircraft in flight. Various modes of flight are provided for, ranging from computer assisted manual modes to fully automatic modes including automatic landing. A high-level system overview as well as a description of each software module comprising the system is provided. Digital systems diagrams are included for each major flight control component and selected flight management functions.

Development and Implementation of a Model-Driven Envelope Protection System for In-Flight Ice Contamination

Science.gov (United States)

Gingras, David R.; Barnhart, Billy P.; Martos, Borja; Ratvasky, Thomas P.; Morelli, Eugene

2011-01-01

Fatal loss-of-control (LOC) accidents have been directly related to in-flight airframe icing. The prototype system presented in this paper directly addresses the need for real-time onboard envelope protection in icing conditions. The combinations of a-priori information and realtime aerodynamic estimations are shown to provide sufficient input for determining safe limits of the flight envelope during in-flight icing encounters. The Icing Contamination Envelope Protection (ICEPro) system has been designed and implemented to identify degradations in airplane performance and flying qualities resulting from ice contamination and provide safe flight-envelope cues to the pilot. Components of ICEPro are described and results from preliminary tests are presented.

Probabilistic Risk Assessment for Astronaut Post Flight Bone Fracture

Science.gov (United States)

Lewandowski, Beth; Myers, Jerry; Licata, Angelo

2015-01-01

Introduction: Space flight potentially reduces the loading that bone can resist before fracture. This reduction in bone integrity may result from a combination of factors, the most common reported as reduction in astronaut BMD. Although evaluating the condition of bones continues to be a critical aspect of understanding space flight fracture risk, defining the loading regime, whether on earth, in microgravity, or in reduced gravity on a planetary surface, remains a significant component of estimating the fracture risks to astronauts. This presentation summarizes the concepts, development, and application of NASA's Bone Fracture Risk Module (BFxRM) to understanding pre-, post, and in mission astronaut bone fracture risk. The overview includes an assessment of contributing factors utilized in the BFxRM and illustrates how new information, such as biomechanics of space suit design or better understanding of post flight activities may influence astronaut fracture risk. Opportunities for the bone mineral research community to contribute to future model development are also discussed. Methods: To investigate the conditions in which spaceflight induced changes to bone plays a critical role in post-flight fracture probability, we implement a modified version of the NASA Bone Fracture Risk Model (BFxRM). Modifications included incorporation of variations in physiological characteristics, post-flight recovery rate, and variations in lateral fall conditions within the probabilistic simulation parameter space. The modeled fracture probability estimates for different loading scenarios at preflight and at 0 and 365 days post-flight time periods are compared. Results: For simple lateral side falls, mean post-flight fracture probability is elevated over mean preflight fracture probability due to spaceflight induced BMD loss and is not fully recovered at 365 days post-flight. In the case of more energetic falls, such as from elevated heights or with the addition of lateral movement

Contribution to diffraction theory

International Nuclear Information System (INIS)

Chako, N.

1966-11-01

In a first part, we have given a general and detailed treatment of the modern theory of diffraction. The rigorous theory is formulated as a boundary value problem of the wave equation or Maxwell equations. However, up to the present time, such a program of treating diffraction by optical systems, even for simple optical instruments, has not been realized due to the complicated character of the boundary conditions. The recent developments show clearly the nature of the approximation of the classical theories originally due to Fresnel and Young, later formulated in a rigorous manner by Kirchhoff and Rubinowicz, respectively and, at the same time the insufficiency of these theories in explaining a number of diffraction phenomena. Furthermore, we have made a study of the limitations of the approximate theories and the recent attempts to improve these. The second part is devoted to a general mathematical treatment of the theory of diffraction of optical systems including aberrations. After a general and specific analysis of geometrical and wave aberrations along classical and modern (Nijboer) lines, we have been able to evaluate the diffraction integrals representing the image field at any point in image space explicitly, when the aberrations are small. Our formulas are the generalisations of all anterior results obtained by previous investigators. Moreover, we have discussed the Zernike-Nijboer theory of aberration and generalised it not only for rotational systems, but also for non-symmetric systems as well, including the case of non circular apertures. The extension to non-circular apertures is done by introducing orthogonal functions or polynomials over such aperture shapes. So far the results are valid for small aberrations, that is to say, where the deformation of the real wave front emerging from the optical system is less than a wave length of light or of the electromagnetic wave from the ideal wave front. If the aberrations are large, then one must employ the

Diffractive charm and jet production at HERA

International Nuclear Information System (INIS)

Savin, Alexander A.

2003-01-01

A new high precision inclusive measurement of the diffractive production of D* ± (2010) mesons in deep inelastic scattering (DIS) in the kinematic region Q 2 >1.5 GeV 2 , 0.02 IP 2 2 , 165 2 , χ IP < 0.03 are presented. Diffractive parton densities extracted using a NLO DGLAP QCD fit are used for comparisons with diffractive DIS and PHP dijet and open charm cross sections at HERA and the Tevatron, thus testing the factorization properties of hard diffraction

A non-invasive analysis of 'proto-majolica' pottery from southern Italy by TOF neutron diffraction

Energy Technology Data Exchange (ETDEWEB)

Barilaro, D; Crupi, V; Majolino, D; Venuti, V [Dipartimento di Fisica, Universita di Messina, Contrada da Papardo, Salita Sperone 31, PO Box 55, 98166, Sant Agata, Messina (Italy); Barone, G [Dipartmento di Scienze Geologiche, Universita di Catania, Corso Italia 55, 95129 Catania (Italy); Tigano, G [Soprintendenza Beni Culturali ed Ambientali di Messina, Sezione Archeologica, Viale Boccetta 38, 98100 Messina (Italy); Imberti, S [Consiglio Nazionale delle Ricerche, Istituto Sistemi Complessi: Sezione di Firenze, Via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy); Kockelmann, W [ISIS Facility, Rutherford Appleton Laboratory, Didcot OX11 0QX (United Kingdom)], E-mail: vvenuti@unime.it

2008-03-12

The employment of time-of-flight (TOF) neutron diffraction allowed for the quantitative determination of mineral phase contents of the ceramic bulk of several pottery fragments coming from Milazzo and Messina (Sicily, southern Italy). From an historical-artistic point of view, all the samples were dated back to the 12th to 13th centuries AD and classified as belonging to the 'proto-majolica' ceramic class. The adopted procedure is absolutely non-destructive, so that measurements were performed on the entire fragments without any sampling. The information derived, by applying the Rietveld analysis method, allowed us to formulate hypotheses concerning the fabrication processes of the artefacts.

Axial channeling in electron diffraction

International Nuclear Information System (INIS)

Ichimiya, A.; Lehmpfuhl, G.

1978-01-01

Kossel patterns from Silicon and Niobium were obtained with a convergent electron beam. An intensity maximum in the direction of the zone axes [001] and [111] of Nb was interpreted as axial channeling. The intensity distribution in Kossel patterns was calculated by means of the Bloch wave picture of the dynamical theory of electron diffraction. Particularly zone axis patterns were calculated for different substance-energy combinations and they were compared with experimental observations. The intensity distribution in the calculated Kossel patterns was very sensitive to the model of absorption and it was found that a treatment of the absorption close to the model of Humphreys and Hirsch [Phil. Mag. 18, 115 (1968)] gave the best agreement with the experimental observations. Furthermore it is shown which Bloch waves are important for the intensity distribution in the Kossel patterns, how they are absorbed and how they change with energy. (orig.) [de

Neutron-diffraction measurements of stress

International Nuclear Information System (INIS)

Holden, T.M.

1995-01-01

Experiments on bent steam-generator tubing have shown that different diffraction peaks, (1 1 1) or (0 0 2), give different results for the sign and magnitude of the stress and strain. From an engineering standpoint, the macroscopic stress field cannot be both positive and negative in the same volume, so this difference must be due to intergranular effects superposed on the macroscopic stress field. Uniaxial tensile test experiments with applied stresses beyond the 0.2% offset yield stress, help to understand this anomaly, by demonstrating the different strain response to applied stress along different crystallographic axes.When Zr-alloys are cooled from elevated temperatures, thermal stresses always develop, so that it is difficult to obtain a stress-free lattice spacing from which residual strains may be derived. From measurements of the temperature dependence of lattice spacing, the temperature at which the thermal stresses vanish may be found. From the lattice spacing at this temperature the stress-free lattice spacings at room temperature can be obtained readily.To interpret the measured strains in terms of macroscopic stress fields it is necessary to know the diffraction elastic constants. Neutron diffraction measurements of the diffraction elastic constants in a ferritic steel for the [1 1 0], [0 0 2] and [2 2 2] crystallographic axes, in directions parallel and perpendicular to the applied stress are compared with theoretical diffraction elastic constants. (orig.)

A Medipix quantum area detector allows rotation electron diffraction data collection from submicrometre three-dimensional protein crystals

International Nuclear Information System (INIS)

Nederlof, Igor; Genderen, Eric van; Li, Yao-Wang; Abrahams, Jan Pieter

2013-01-01

An ultrasensitive Medipix2 detector allowed the collection of rotation electron-diffraction data from single three-dimensional protein nanocrystals for the first time. The data could be analysed using the standard X-ray crystallography programs MOSFLM and SCALA. When protein crystals are submicrometre-sized, X-ray radiation damage precludes conventional diffraction data collection. For crystals that are of the order of 100 nm in size, at best only single-shot diffraction patterns can be collected and rotation data collection has not been possible, irrespective of the diffraction technique used. Here, it is shown that at a very low electron dose (at most 0.1 e − Å −2 ), a Medipix2 quantum area detector is sufficiently sensitive to allow the collection of a 30-frame rotation series of 200 keV electron-diffraction data from a single ∼100 nm thick protein crystal. A highly parallel 200 keV electron beam (λ = 0.025 Å) allowed observation of the curvature of the Ewald sphere at low resolution, indicating a combined mosaic spread/beam divergence of at most 0.4°. This result shows that volumes of crystal with low mosaicity can be pinpointed in electron diffraction. It is also shown that strategies and data-analysis software (MOSFLM and SCALA) from X-ray protein crystallography can be used in principle for analysing electron-diffraction data from three-dimensional nanocrystals of proteins

Precise structural analysis of methane hydrate by neutron diffraction

International Nuclear Information System (INIS)

Igawa, Naoki; Hoshikawa, Akinori; Ishii, Yoshinobu

2006-01-01

Methane hydrate has attracted great interest as an energy resource to replace natural gas since this material is deposited in the seafloor and the deposits are estimated to exceed those of natural gas. Understanding the physical proprieties, such as the temperature dependence of the crystal structure, helps to specify the optimum environmental temperature and pressure during drilling, transport, and storage of methane hydrate. Clathrate hydrates consisted of encaging atomic and/or molecular species as a guest and host water formed by a hydrogen bonding. Although many studies on the clathrate hydrate including methane hydrate were reported, no detailed crystallographic property has yet been cleared. We focused on the motion of methane in the clathrate hydrate by the neutron diffraction. The crystal structure of the methane hydrate was analyzed by the applying the combination of the Rietveld refinement and the maximum entropy method (MEM) to neutron powder diffraction. Temperature dependence of the scattering-length density distribution maps revealed that the motion of methane molecules differs between the shapes of dodecahedron and tetrakaidecahedron. (author)

The dynamics of diffracted rays in foams

Energy Technology Data Exchange (ETDEWEB)

Tufaile, A., E-mail: tufaile@usp.br; Tufaile, A.P.B.

2015-12-18

We have studied some aspects of the optics of the light scattering in foams. This paper describes the difference between rays and diffracted rays from the point of view of geometrical theory of diffraction. We have represented some bifurcations of light rays using dynamical systems. Based on our observations of foams, we created a solid optical device. The interference patterns of light scattering in foams forming Airy fringes were explored observing the pattern named as the eye of Horus. In the cases we examine, these Airy fringes are associated with light scattering in curved surfaces, while the halo formation is related to the law of edge diffraction. We are proposing a Pohl interferometer using a three-sided bubble/Plateau border system. - Highlights: • We obtained halos scattering light in foams. • We model the light scattering in foams using the geometrical theory of diffraction. • We examine the difference between rays and the diffracted rays. • We developed optical devices for diffracted rays.

Electron diffraction of CBr{sub 4} in superfluid helium droplets: A step towards single molecule diffraction

Energy Technology Data Exchange (ETDEWEB)

He, Yunteng; Zhang, Jie; Kong, Wei, E-mail: wei.kong@oregonstate.edu [Department of Chemistry, Oregon State University, Corvallis, Oregon 97331-4003 (United States)

2016-07-21

We demonstrate the practicality of electron diffraction of single molecules inside superfluid helium droplets using CBr{sub 4} as a testing case. By reducing the background from pure undoped droplets via multiple doping, with small corrections for dimers and trimers, clearly resolved diffraction rings of CBr{sub 4} similar to those of gas phase molecules can be observed. The experimental data from CBr{sub 4} doped droplets are in agreement with both theoretical calculations and with experimental results of gaseous species. The abundance of monomers and clusters in the droplet beam also qualitatively agrees with the Poisson statistics. Possible extensions of this approach to macromolecular ions will also be discussed. This result marks the first step in building a molecular goniometer using superfluid helium droplet cooling and field induced orientation. The superior cooling effect of helium droplets is ideal for field induced orientation, but the diffraction background from helium is a concern. This work addresses this background issue and identifies a possible solution. Accumulation of diffraction images only becomes meaningful when all images are produced from molecules oriented in the same direction, and hence a molecular goniometer is a crucial technology for serial diffraction of single molecules.

Diffractive optical elements for space communication terminals

OpenAIRE

Herzig, Hans-Peter; Ehbets, Peter; Teijido, Juan M.; Weible, Kenneth J.; Heimbeck, Hans-Joerg

2007-01-01

The potential of diffractive optical elements for advanced laser communication terminals has been investigated. Applications include beam shaping of high- power laser diode arrays, optical filter elements for position detection and hybrid (refractive/diffractive) elements. In addition, we present a design example of a miniaturized terminal including diffractive optics.

Diffractive production off nuclei-shadow of hadronic bremsstrahlung

International Nuclear Information System (INIS)

Bialas, A.; Czyz, W.

1974-01-01

Diffractive production on nuclei is calculated using as an input a specific model for diffractive production on nucleons. In this model diffractive production is described as a shadow of non-diffractive multiple production of particles. The mechanism for non-diffractive production is taken to be hadronic bremsstrahlung of independently produced clusters. It is shown that such a model naturally explains the strikingly simple pattern of absorption observed in coherent production on nuclei. Possible generalizations of these results are indicated. (author)

NASA balloon design and flight - Philosophy and criteria

Science.gov (United States)

Smith, I. S., Jr.

1993-01-01

The NASA philosophy and criteria for the design and flight of scientific balloons are set forth and discussed. The thickness of balloon films is standardized at 20.3 microns to isolate potential film problems, and design equations are given for specific balloon parameters. Expressions are given for: flight-stress index, total required thickness, cap length, load-tape rating, and venting-duct area. The balloon design criteria were used in the design of scientific balloons under NASA auspices since 1986, and the resulting designs are shown to be 95 percent effective. These results represent a significant increase in the effectiveness of the balloons and therefore indicate that the design criteria are valuable. The criteria are applicable to four balloon volume classes in combination with seven payload ranges.

A novel method to remove the background from x-ray diffraction signal

DEFF Research Database (Denmark)

Zheng, Yi; Speller, Robert; Griffiths, Jennifer

2018-01-01

The first step that is required to extract the correct information from a two-dimensional (2D) diffraction signature is to remove the background accurately. However, direct background subtraction inevitably overcorrects the signal as it does not take into account the attenuation by the sample. Ot...... proposes a novel method that combines peak fitting and experimental results to estimate the background for 2D XRD signals....

Eclipse - tow flight closeup and release

Science.gov (United States)

1998-01-01

This clip, running 15 seconds in length, shows the QF-106 'Delta Dart' gear down, with the tow rope secured to the attachment point above the aircraft nose. First there is a view looking back from the C-141A, then looking forward from the nose of the QF-106, and finally a shot of the aircraft being released from the tow rope. NASA Dryden Flight Research Center, Edwards, California, supported a Kelly Space and Technology, Inc. (KST)/U.S. Air Force project known as Eclipse, which demonstrated a reusable tow launch vehicle concept. The purpose of the project was to demonstrate a reusable tow launch vehicle concept that had been conceived and patented by KST. Kelly Space obtained a contract with the USAF Research Laboratory for the tow launch demonstration project under the Small Business Innovation Research (SBIR) program. The USAF SBIR contract included the modifications to turn the QF-106 into the Experimental Demonstrator #1 (EXD-01), and the C141A aircraft to incorporate the tow provisions to link the two aircraft, as well as conducting flight tests. The demonstration consisted of ground and flight tests. These tests included a Combined Systems Test of both airplanes joined by a tow rope, a towed taxi test, and six towed flights. The primary goal of the project was demonstrating the tow phase of the Eclipse concept using a scaled-down tow aircraft (C-141A) and a representative aerodynamically-shaped aircraft (QF-106A) as a launch vehicle. This was successfully accomplished. On December 20, 1997, NASA research pilot Mark Stucky flew a QF-106 on the first towed flight behind an Air Force C-141 in the joint Eclipse project with KST to demonstrate a reusable tow launch vehicle concept developed by KST. Kelly Space and Technology hoped to use the data from the tow tests to validate a tow-to-launch procedure for reusable space launch vehicles. Stucky flew six successful tow tests between December 1997 and February 6, 1998. On February 6, 1998, the sixth and final towed

A Comparitive Analysis of the Influence of Weather on the Flight Altitudes of Birds.

Science.gov (United States)

Shamoun-Baranes, Judy; van Loon, Emiel; van Gasteren, Hans; van Belle, Jelmer; Bouten, Willem; Buurma, Luit

2006-01-01

Birds pose a serious risk to flight safety worldwide. A Bird Avoidance Model (BAM) is being developed in the Netherlands to reduce the risk of bird aircraft collisions. In order to develop a temporally and spatially dynamic model of bird densities, data are needed on the flight-altitude distribution of birds and how this is influenced by weather. This study focuses on the dynamics of flight altitudes of several species of birds during local flights over land in relation to meteorological conditions.We measured flight altitudes of several species in the southeastern Netherlands using tracking radar during spring and summer 2000. Representatives of different flight strategy groups included four species: a soaring species (buzzard ), an obligatory aerial forager (swift Apus apus), a flapping and gliding species (blackheaded gull Larus ridibundus), and a flapping species (starling Sturnus vulgaris).Maximum flight altitudes varied among species, during the day and among days. Weather significantly influenced the flight altitudes of all species studied. Factors such as temperature, relative humidity, atmospheric instability, cloud cover, and sea level pressure were related to flight altitudes. Different combinations of factors explained 40% 70% of the variance in maximum flight altitudes. Weather affected flight strategy groups differently. Compared to flapping species, buzzards and swifts showed stronger variations in maximum daily altitude and f lew higher under conditions reflecting stronger thermal convection. The dynamic vertical distributions of birds are important for risk assessment and mitigation measures in flight safety as well as wind turbine studies.

The NASA Human Space Flight Supply Chain, Current and Future

Science.gov (United States)

Zapata, Edgar

2007-01-01

The current NASA Human Space Flight transportation system, the Space Shuttle, is scheduled for final flight in 2010. The Exploration initiative will create a new capability with a combination of existing systems and new flight and ground elements. To fully understand and act on the implications of such change it is necessary to understand what, how, when and where such changes occur and more importantly, how all these interact. This paper presents Human Space Flight, with an emphasis on KSC Launch and Landing, as a Supply Chain of both information and materials. A supply chain methodology for understanding the flow of information and materials is presented. Further, modeling and simulation projects funded by the Exploration initiative to understand the NASA Exploration Supply Chain are explained. Key concepts and their purpose, including the Enterprise, Locations, Physical and Organizational Functional Units, Products, and Resources, are explained. It is shown that the art, science and perspective of Supply Chain Management is not only applicable to such a government & contractor operation, it is also an invaluable approach for understanding, focusing improvement and growth. It is shown that such commercial practice applies to Human Space Flight and is invaluable towards one day creating routine, affordable access to and from space.

Observation of coherent optical phonons excited by femtosecond laser radiation in Sb films by ultrafast electron diffraction method

Energy Technology Data Exchange (ETDEWEB)

Mironov, B. N.; Kompanets, V. O.; Aseev, S. A., E-mail: isanfemto@yandex.ru [Russian Academy of Sciences, Institute of Spectroscopy (Russian Federation); Ischenko, A. A. [Moscow Technological University, Institute of High Chemical Technologies (Russian Federation); Kochikov, I. V. [Moscow State University (Russian Federation); Misochko, O. V. [Russian Academy of Sciences, Institute of Solid State Physics (Russian Federation); Chekalin, S. V.; Ryabov, E. A. [Russian Academy of Sciences, Institute of Spectroscopy (Russian Federation)

2017-03-15

The generation of coherent optical phonons in a polycrystalline antimony film sample has been investigated using femtosecond electron diffraction method. Phonon vibrations have been induced in the Sb sample by the main harmonic of a femtosecond Ti:Sa laser (λ = 800 nm) and probed by a pulsed ultrashort photoelectron beam synchronized with the pump laser. The diffraction patterns recorded at different times relative to the pump laser pulse display oscillations of electron diffraction intensity corresponding to the frequencies of vibrations of optical phonons: totally symmetric (A{sub 1g}) and twofold degenerate (E{sub g}) phonon modes. The frequencies that correspond to combinations of these phonon modes in the Sb sample have also been experimentally observed.

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

Science.gov (United States)

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.

High-energy electron diffraction and microscopy

CERN Document Server

Peng, L M; Whelan, M J

2011-01-01

This book provides a comprehensive introduction to high energy electron diffraction and elastic and inelastic scattering of high energy electrons, with particular emphasis on applications to modern electron microscopy. Starting from a survey of fundamental phenomena, the authors introduce the most important concepts underlying modern understanding of high energy electron diffraction. Dynamical diffraction in transmission (THEED) and reflection (RHEED) geometries is treated using ageneral matrix theory, where computer programs and worked examples are provided to illustrate the concepts and to f

Diffractive variable beam splitter: optimal design.

Science.gov (United States)

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.

Diffraction enhanced kinetic depth X-ray imaging

Science.gov (United States)

Dicken, A.

An increasing number of fields would benefit from a single analytical probe that can characterise bulk objects that vary in morphology and/or material composition. These fields include security screening, medicine and material science. In this study the X-ray region is shown to be an effective probe for the characterisation of materials. The most prominent analytical techniques that utilise X-radiation are reviewed. The study then focuses on methods of amalgamating the three dimensional power of kinetic depth X-ray (KDFX) imaging with the materials discrimination of angular dispersive X-ray diffraction (ADXRD), thus providing KDEX with a much needed material specific counterpart. A knowledge of the sample position is essential for the correct interpretation of diffraction signatures. Two different sensor geometries (i.e. circumferential and linear) that are able to collect end interpret multiple unknown material diffraction patterns and attribute them to their respective loci within an inspection volume are investigated. The circumferential and linear detector geometries are hypothesised, simulated and then tested in an experimental setting with the later demonstrating a greater ability at discerning between mixed diffraction patterns produced by differing materials. Factors known to confound the linear diffraction method such as sample thickness and radiation energy have been explored and quantified with a possible means of mitigation being identified (i.e. via increasing the sample to detector distance). A series of diffraction patterns (following the linear diffraction approach) were obtained from a single phantom object that was simultaneously interrogated via KDEX imaging. Areas containing diffraction signatures matched from a threat library have been highlighted in the KDEX imagery via colour encoding and match index is inferred by intensity. This union is the first example of its kind and is called diffraction enhanced KDEX imagery. Finally an additional

Flight Planning

Science.gov (United States)

1991-01-01

Seagull Technology, Inc., Sunnyvale, CA, produced a computer program under a Langley Research Center Small Business Innovation Research (SBIR) grant called STAFPLAN (Seagull Technology Advanced Flight Plan) that plans optimal trajectory routes for small to medium sized airlines to minimize direct operating costs while complying with various airline operating constraints. STAFPLAN incorporates four input databases, weather, route data, aircraft performance, and flight-specific information (times, payload, crew, fuel cost) to provide the correct amount of fuel optimal cruise altitude, climb and descent points, optimal cruise speed, and flight path.

Diffraction efficiency calculations of polarization diffraction gratings with surface relief

Science.gov (United States)

Nazarova, D.; Sharlandjiev, P.; Berberova, N.; Blagoeva, B.; Stoykova, E.; Nedelchev, L.

2018-03-01

In this paper, we evaluate the optical response of a stack of two diffraction gratings of equal one-dimensional periodicity. The first one is a surface-relief grating structure; the second, a volume polarization grating. This model is based on our experimental results from polarization holographic recordings in azopolymer films. We used films of commercially available azopolymer (poly[1-[4-(3-carboxy-4-hydroxyphenylazo) benzenesulfonamido]-1,2-ethanediyl, sodium salt]), shortly denoted as PAZO. During the recording process, a polarization grating in the volume of the material and a relief grating on the film surface are formed simultaneously. In order to evaluate numerically the optical response of this “hybrid” diffraction structure, we used the rigorous coupled-wave approach (RCWA). It yields stable numerical solutions of Maxwell’s vector equations using the algebraic eigenvalue method.

Diffractive beauty production at the LHC

International Nuclear Information System (INIS)

Eggert, K.; Morsch, A.

1994-01-01

Using the framework of Pomeron exchange to describe diffractive pp collisions at the LHC we discuss beauty production in those events. The cross sections for beauty production at different diffractive masses and the topology for the beauty particles and the underlying event are given. When triggering on large diffractive masses, the beauty system is boosted into the Pomeron hemisphere opposite the underlying event, which tends to follow the excited proton direction. This may offer some advantages for the acceptance of beauty and its reconstruction in forward spectrometers. For the identification of diffractive events at the LHC collider, we present a scheme to measure the momentum loss of forward protons in the range 2x10 -3 < Δp/p <0.1. This momentum loss can be determined with a precision of about 10%. ((orig.))

Neutron diffraction and oxide research

International Nuclear Information System (INIS)

Hunter, B.; Howard, C.J.; Kennedy, B.J.

1999-01-01

Oxide compounds form a large class of interesting materials that have a diverse range of mechanical and electronic properties. This diversity and its commercial implications has had a significant impact on physics research. This is particularly evident in the fields of superconductivity magnetoresistivity and ferroelectricity, where discoveries in the last 15 years have given rise to significant shifts in research activities. Historically, oxides have been studied for many years, but it is only recently that significant effort has been diverted to the study of oxide materials for their application to mechanical and electronic devices. An important property of such materials is the atomic structure, for the determination of which diffraction techniques are ideally suited. Recent examples of structure determinations using neutron diffraction in oxide based systems are high temperature superconductors, where oxygen defects are a key factor. Here, neutron diffraction played a major role in determining the effect of oxygen on the superconducting properties. Similarly, neutron diffraction has enjoyed much success in the determination of the structures of the manganate based colossal magnetoresistive (CMR) materials. In both these cases the structure plays a pivotal role in determining theoretical models of the electronic properties. The neutron scattering group at ANSTO has investigated several oxide systems using neutron powder diffraction. Two such systems are presented in this paper; the zirconia-based materials that are used as engineering materials, and the perovskite-based oxides that include the well known cuprate superconductors and the manganate CMR materials

Flight Planning in the Cloud

Science.gov (United States)

Flores, Sarah L.; Chapman, Bruce D.; Tung, Waye W.; Zheng, Yang

2011-01-01

This new interface will enable Principal Investigators (PIs), as well as UAVSAR (Uninhabited Aerial Vehicle Synthetic Aperture Radar) members to do their own flight planning and time estimation without having to request flight lines through the science coordinator. It uses an all-in-one Google Maps interface, a JPL hosted database, and PI flight requirements to design an airborne flight plan. The application will enable users to see their own flight plan being constructed interactively through a map interface, and then the flight planning software will generate all the files necessary for the flight. Afterward, the UAVSAR team can then complete the flight request, including calendaring and supplying requisite flight request files in the expected format for processing by NASA s airborne science program. Some of the main features of the interface include drawing flight lines on the map, nudging them, adding them to the current flight plan, and reordering them. The user can also search and select takeoff, landing, and intermediate airports. As the flight plan is constructed, all of its components are constantly being saved to the database, and the estimated flight times are updated. Another feature is the ability to import flight lines from previously saved flight plans. One of the main motivations was to make this Web application as simple and intuitive as possible, while also being dynamic and robust. This Web application can easily be extended to support other airborne instruments.

Combined neutron and synchrotron X-ray diffraction study of Sr/Mg-doped lanthanum gallates up to high temperatures

Science.gov (United States)

Guenter, M. M.; Lerch, M.; Boysen, H.; Toebbens, D.; Suard, E.; Baehtz, C.

2006-08-01

Combined neutron diffraction and high-resolution synchrotron X-ray powder diffraction methods have been used to examine the crystal structures of two sample sets of Sr/Mg-doped Lanthanum gallate with the compositions La0.9Sr0.1Ga1-yMgyO3-0.5(0.1+y) (y=0, 0.1, 0.2) and La0.8Sr0.2Ga1-yMgyO3-0.5(0.2+y) (y=0.15, 0.2) up to 900 °C. At room temperature all samples of the first series exhibit orthorhombic structures with space group Imma: La0.9Sr0.1GaO2.95: a=5.4904(1)Å, b=7.7757(1)Å, c=5.5229(1)Å; La0.9Sr0.1Ga0.9Mg0.1O2.9: a=5.5100(1)Å, b=7.8080(1)Å, c=5.5411(1)Å; La0.9Sr0.1Ga0.8Mg0.2O2.85: a=5.5269(1)Å, b=7.8318(2)Å, c=5.5459(1)Å. The samples of the second series have the cubic perovskite structure with space group Pm3¯m at room temperature: La0.8Sr0.2Ga0.85Mg0.15O2.825: a=3.9160(1)Å; La0.8Sr0.2Ga0.8Mg0.20O2.80: a=3.9195(1)Å. Samples of the first series transform from the orthorhombic to a rhombohedral (Imma→R3¯c) structure at ˜170 °C for La0.9Sr0.1GaO2.95, at ˜430 °C for La0.9Sr0.1Ga0.9Mg0.1O2.9, and between 600 and 700 °C for La0.9Sr0.1Ga0.8Mg0.2O2.85. Both La0.8Sr0.2Ga0.85Mg0.15O2.825 and La0.8Sr0.2Ga0.8Mg0.2 show no structural deviations from the cubic aristotype over the whole temperature range. The room temperature Imma structures of the first series are justified by a domain model and are rationalized in terms of static disorder increasing with Mg content, thus driving the phase transition temperatures to higher values in agreement with tolerance factor considerations. The distortion of the rhombohedral high-temperature phases (octahedra tilting and compression) and the effect of phase transitions on the ionic conductivity are discussed.

Structure solution from powder neutron and x-ray diffraction data: getting the best of both worlds

International Nuclear Information System (INIS)

Hunter, B.A.

2000-01-01

Full text: Powder diffraction methods have traditionally been used in three main areas: phase identification and quantification, lattice parameter determination and structure refinement. Until recently structure solution has been the almost exclusive domain of single crystal diffraction methods, predominantly using x-rays. The increasing use of synchrotron and neutron sources, and the unrelenting advances in computing hardware and software means that powder methods are challenging single crystal methods as a practical method for structure solution, especially when single crystal method can not be applied. It is known that structural refinements from a known starting structure using combined X-ray and neutron data sets are capable of providing highly accurate structures. Likewise, using combined x-ray and neutron powder diffraction data in the structure solution process should also be a powerful technique, although to date no one is pursuing this methodology. This paper present examples of solutions to the problem. Namely we are using high resolution powder X-ray and neutron methods to solve the structures of molecular materials and minerals, then refining the structures using both sets of data. In this way we exploit the advantages of both methods while minimising the disadvantages. We present our solution for a small amino acid structure, a metalorganic and a mineral structure

Light distribution in diffractive multifocal optics and its optimization.

Science.gov (United States)

Portney, Valdemar

2011-11-01

To expand a geometrical model of diffraction efficiency and its interpretation to the multifocal optic and to introduce formulas for analysis of far and near light distribution and their application to multifocal intraocular lenses (IOLs) and to diffraction efficiency optimization. Medical device consulting firm, Newport Coast, California, USA. Experimental study. Application of a geometrical model to the kinoform (single focus diffractive optical element) was expanded to a multifocal optic to produce analytical definitions of light split between far and near images and light loss to other diffraction orders. The geometrical model gave a simple interpretation of light split in a diffractive multifocal IOL. An analytical definition of light split between far, near, and light loss was introduced as curve fitting formulas. Several examples of application to common multifocal diffractive IOLs were developed; for example, to light-split change with wavelength. The analytical definition of diffraction efficiency may assist in optimization of multifocal diffractive optics that minimize light loss. Formulas for analysis of light split between different foci of multifocal diffractive IOLs are useful in interpreting diffraction efficiency dependence on physical characteristics, such as blaze heights of the diffractive grooves and wavelength of light, as well as for optimizing multifocal diffractive optics. Disclosure is found in the footnotes. Copyright © 2011 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

Axial and focal-plane diffraction catastrophe integrals

International Nuclear Information System (INIS)

Berry, M V; Howls, C J

2010-01-01

Exact expressions in terms of Bessel functions are found for some of the diffraction catastrophe integrals that decorate caustics in optics and mechanics. These are the axial and focal-plane sections of the elliptic and hyperbolic umbilic diffraction catastrophes, and symmetric elliptic and hyperbolic unfoldings of the X 9 diffraction catastrophes. These representations reveal unexpected relations between the integrals.

Sensitivity of photoelectron diffraction to conformational changes of adsorbed molecules: Tetra-tert-butyl-azobenzene/Au(111

Directory of Open Access Journals (Sweden)

A. Schuler

2017-01-01

Full Text Available Electron diffraction is a standard tool to investigate the atomic structure of surfaces, interfaces, and adsorbate systems. In particular, photoelectron diffraction is a promising candidate for real-time studies of structural dynamics combining the ultimate time resolution of optical pulses and the high scattering cross-sections for electrons. In view of future time-resolved experiments from molecular layers, we studied the sensitivity of photoelectron diffraction to conformational changes of only a small fraction of molecules in a monolayer adsorbed on a metallic substrate. 3,3′,5,5′-tetra-tert-butyl-azobenzene served as test case. This molecule can be switched between two isomers, trans and cis, by absorption of ultraviolet light. X-ray photoelectron diffraction patterns were recorded from tetra-tert-butyl-azobenzene/Au(111 in thermal equilibrium at room temperature and compared to patterns taken in the photostationary state obtained by exposing the surface to radiation from a high-intensity helium discharge lamp. Difference patterns were simulated by means of multiple-scattering calculations, which allowed us to determine the fraction of molecules that underwent isomerization.

Extinction correction in white X-ray and neutron diffraction

International Nuclear Information System (INIS)

Tomiyoshi, S.; Yamada, M.; Watanabe, H.

1980-01-01

Extinction effects in white-beam X-ray and neutron diffraction are considered. In white-beam diffraction, a small deviation of the wavelength from the Bragg condition Δlambda is a variable which represents the line profile of the diffraction peaks, so that by using the new parameter Δlambda the theory is converted to one in white-beam diffraction. It is shown that for a convex crystal, primary extinction agrees with the results calculated already for monochromatic diffraction. The same relation is shown to hold in secondary extinction. It is concluded that extinction theory derived for monochromatic diffraction is applicable without any modification in white-beam diffraction. (Auth.)

NIST/Sandia/ICDD Electron Diffraction Database: A Database for Phase Identification by Electron Diffraction.

Science.gov (United States)

Carr, M J; Chambers, W F; Melgaard, D; Himes, V L; Stalick, J K; Mighell, A D

1989-01-01

A new database containing crystallographic and chemical information designed especially for application to electron diffraction search/match and related problems has been developed. The new database was derived from two well-established x-ray diffraction databases, the JCPDS Powder Diffraction File and NBS CRYSTAL DATA, and incorporates 2 years of experience with an earlier version. It contains 71,142 entries, with space group and unit cell data for 59,612 of those. Unit cell and space group information were used, where available, to calculate patterns consisting of all allowed reflections with d -spacings greater than 0.8 A for ~ 59,000 of the entries. Calculated patterns are used in the database in preference to experimental x-ray data when both are available, since experimental x-ray data sometimes omits high d -spacing data which falls at low diffraction angles. Intensity data are not given when calculated spacings are used. A search scheme using chemistry and r -spacing (reciprocal d -spacing) has been developed. Other potentially searchable data in this new database include space group, Pearson symbol, unit cell edge lengths, reduced cell edge length, and reduced cell volume. Compound and/or mineral names, formulas, and journal references are included in the output, as well as pointers to corresponding entries in NBS CRYSTAL DATA and the Powder Diffraction File where more complete information may be obtained. Atom positions are not given. Rudimentary search software has been written to implement a chemistry and r -spacing bit map search. With typical data, a full search through ~ 71,000 compounds takes 10~20 seconds on a PDP 11/23-RL02 system.

A reverse time of flight analyzer facility at the ETRR-1 reactor

Energy Technology Data Exchange (ETDEWEB)

Maayouf, R M.A.; El-Shafey, A S; Khalil, M I [Reactor and Neutron Physics Dept., NRC, Atomic Energy Authority, Cairo (Egypt)

1997-12-31

The present work deals both with the theory and performance of a reverse-time-of-flight (RTOF) analyzer designed to analyze pulses emitted from a fourier chopper recently put into operation at the ETRR-1 reactor. The RTOF analyze was found to be adequate for use with pick up pulses from the fourier chopper which operates following a frequency window suitable for rotation rates from 0-9000 rpm; synchronically with neutron pulses from a {sup 6} Li glass detector set at time focusing geometry for scattering angle 20=90 degree. It was possible, with the present RTOF analyzer to obtain diffraction patterns at neutron wavelength range between 1 - 4 A within a resolution = 0.5%. 8 FIGS.

Advanced transport operating system software upgrade: Flight management/flight controls software description

Science.gov (United States)

Clinedinst, Winston C.; Debure, Kelly R.; Dickson, Richard W.; Heaphy, William J.; Parks, Mark A.; Slominski, Christopher J.; Wolverton, David A.

1988-01-01

The Flight Management/Flight Controls (FM/FC) software for the Norden 2 (PDP-11/70M) computer installed on the NASA 737 aircraft is described. The software computes the navigation position estimates, guidance commands, those commands to be issued to the control surfaces to direct the aircraft in flight based on the modes selected on the Advanced Guidance Control System (AGSC) mode panel, and the flight path selected via the Navigation Control/Display Unit (NCDU).

A Medipix quantum area detector allows rotation electron diffraction data collection from submicrometre three-dimensional protein crystals

Energy Technology Data Exchange (ETDEWEB)

Nederlof, Igor; Genderen, Eric van; Li, Yao-Wang; Abrahams, Jan Pieter, E-mail: abrahams@chem.leidenuniv.nl [Leiden University, Einsteinweg 55, 2333 CC Leiden (Netherlands)

2013-07-01

An ultrasensitive Medipix2 detector allowed the collection of rotation electron-diffraction data from single three-dimensional protein nanocrystals for the first time. The data could be analysed using the standard X-ray crystallography programs MOSFLM and SCALA. When protein crystals are submicrometre-sized, X-ray radiation damage precludes conventional diffraction data collection. For crystals that are of the order of 100 nm in size, at best only single-shot diffraction patterns can be collected and rotation data collection has not been possible, irrespective of the diffraction technique used. Here, it is shown that at a very low electron dose (at most 0.1 e{sup −} Å{sup −2}), a Medipix2 quantum area detector is sufficiently sensitive to allow the collection of a 30-frame rotation series of 200 keV electron-diffraction data from a single ∼100 nm thick protein crystal. A highly parallel 200 keV electron beam (λ = 0.025 Å) allowed observation of the curvature of the Ewald sphere at low resolution, indicating a combined mosaic spread/beam divergence of at most 0.4°. This result shows that volumes of crystal with low mosaicity can be pinpointed in electron diffraction. It is also shown that strategies and data-analysis software (MOSFLM and SCALA) from X-ray protein crystallography can be used in principle for analysing electron-diffraction data from three-dimensional nanocrystals of proteins.

Accurate Charge Densities from Powder Diffraction

DEFF Research Database (Denmark)

Bindzus, Niels; Wahlberg, Nanna; Becker, Jacob

Synchrotron powder X-ray diffraction has in recent years advanced to a level, where it has become realistic to probe extremely subtle electronic features. Compared to single-crystal diffraction, it may be superior for simple, high-symmetry crystals owing to negligible extinction effects and minimal...... peak overlap. Additionally, it offers the opportunity for collecting data on a single scale. For charge densities studies, the critical task is to recover accurate and bias-free structure factors from the diffraction pattern. This is the focal point of the present study, scrutinizing the performance...

Hard diffraction at HERA and Tevatron

International Nuclear Information System (INIS)

Kaidalov, A.B.

2001-01-01

A relation between hard diffraction at HERA and Tevatron is discussed. A model, which takes into account unitarity effects is developed for interaction of high-energy virtual photons with nucleons. It is shown that this model gives a good description of HERA data on both total γ* p total cross section and diffractive dissociation of virtual photons in a broad region of Q 2 . It is shown how to describe the CDF data on diffractive jet production at Tevatron using an information on distribution of partons in the Pomeron from HERA experiments

Free Flight Ground Testing of ADEPT in Advance of the Sounding Rocket One Flight Experiment

Science.gov (United States)

Smith, B. P.; Dutta, S.

2017-01-01

The Adaptable Deployable Entry and Placement Technology (ADEPT) project will be conducting the first flight test of ADEPT, titled Sounding Rocket One (SR-1), in just two months. The need for this flight test stems from the fact that ADEPT's supersonic dynamic stability has not yet been characterized. The SR-1 flight test will provide critical data describing the flight mechanics of ADEPT in ballistic flight. These data will feed decision making on future ADEPT mission designs. This presentation will describe the SR-1 scientific data products, possible flight test outcomes, and the implications of those outcomes on future ADEPT development. In addition, this presentation will describe free-flight ground testing performed in advance of the flight test. A subsonic flight dynamics test conducted at the Vertical Spin Tunnel located at NASA Langley Research Center provided subsonic flight dynamics data at high and low altitudes for multiple center of mass (CoM) locations. A ballistic range test at the Hypervelocity Free Flight Aerodynamics Facility (HFFAF) located at NASA Ames Research Center provided supersonic flight dynamics data at low supersonic Mach numbers. Execution and outcomes of these tests will be discussed. Finally, a hypothesized trajectory estimate for the SR-1 flight will be presented.

Small area analysis using micro-diffraction techniques

International Nuclear Information System (INIS)

Goehner, Raymond P.; Tissot, Ralph G. Jr.; Michael, Joseph R.

2000-01-01

An overall trend toward smaller electronic packages and devices makes it increasingly important and difficult to obtain meaningful diffraction information from small areas. X-ray micro-diffraction, electron back-scattered diffraction (EBSD) and Kossel are micro-diffraction techniques used for crystallographic analysis including texture, phase identification and strain measurements. X-ray micro-diffraction primarily is used for phase analysis and residual strain measurements. X-ray micro-diffraction primarily is used for phase analysis and residual strain measurements of areas between 10 microm to 100 microm. For areas this small glass capillary optics are used for producing a usable collimated x-ray beam. These optics are designed to reflect x-rays below the critical angle therefore allowing for larger solid acceptance angle at the x-ray source resulting in brighter smaller x-ray beams. The determination of residual strain using micro-diffraction techniques is very important to the semiconductor industry. Residual stresses have caused voiding of the interconnect metal which then destroys electrical continuity. Being able to determine the residual stress helps industry to predict failures from the aging effects of interconnects due to this stress voiding. Stress measurements would be impossible using a conventional x-ray diffractometer; however, utilizing a 30 microm glass capillary these small areas are readily assessable for analysis. Kossel produces a wide angle diffraction pattern from fluorescent x-rays generated in the sample by an e-beam in a SEM. This technique can yield very precise lattice parameters for determining strain. Fig. 2 shows a Kossel pattern from a Ni specimen. Phase analysis on small areas is also possible using an energy dispersive spectrometer (EBSD) and x-ray micro-diffraction techniques. EBSD has the advantage of allowing the user to observe the area of interest using the excellent imaging capabilities of the SEM. An EDS detector has been

Principles of the measurement of residual stress by neutron diffraction

Energy Technology Data Exchange (ETDEWEB)

Webster, G A; Ezeilo, A N [Imperial Coll. of Science and Technology, London (United Kingdom). Dept. of Mechanical Engineering

1996-11-01

The presence of residual stresses in engineering components can significantly affect their load carrying capacity and resistance to fracture. In order to quantify their effect it is necessary to know their magnitude and distribution. Neutron diffraction is the most suitable method of obtaining these stresses non-destructively in the interior of components. In this paper the principles of the technique are described. A monochromatic beam of neutrons, or time of flight measurements, can be employed. In each case, components of strain are determined directly from changes in the lattice spacings between crystals. Residual stresses can then be calculated from these strains. The experimental procedures for making the measurements are described and precautions for achieving reliable results discussed. These include choice of crystal planes on which to make measurements, extent of masking needed to identify a suitable sampling volume, type of detector and alignment procedure. Methods of achieving a stress free reference are also considered. A selection of practical examples is included to demonstrate the success of the technique. (author) 14 figs., 1 tab., 18 refs.

Principles of the measurement of residual stress by neutron diffraction

International Nuclear Information System (INIS)

Webster, G.A.; Ezeilo, A.N.

1996-01-01

The presence of residual stresses in engineering components can significantly affect their load carrying capacity and resistance to fracture. In order to quantify their effect it is necessary to know their magnitude and distribution. Neutron diffraction is the most suitable method of obtaining these stresses non-destructively in the interior of components. In this paper the principles of the technique are described. A monochromatic beam of neutrons, or time of flight measurements, can be employed. In each case, components of strain are determined directly from changes in the lattice spacings between crystals. Residual stresses can then be calculated from these strains. The experimental procedures for making the measurements are described and precautions for achieving reliable results discussed. These include choice of crystal planes on which to make measurements, extent of masking needed to identify a suitable sampling volume, type of detector and alignment procedure. Methods of achieving a stress free reference are also considered. A selection of practical examples is included to demonstrate the success of the technique. (author) 14 figs., 1 tab., 18 refs

Using Engine Thrust for Emergency Flight Control: MD-11 and B-747 Results

Science.gov (United States)

Burcham, Frank W., Jr.; Maine, Trindel A.; Burken, John J.; Bull, John

1998-01-01

With modern digital control systems, using engine thrust for emergency flight control to supplement or replace failed aircraft normal flight controls has become a practical consideration. The NASA Dryden Flight Research Center has developed a propulsion-controlled aircraft (PCA) system in which computer-controlled engine thrust provides emergency flight control. An F-15 and an MD-11 airplane have been landed without using any flight control surfaces. Preliminary studies have also been conducted that show that engines on only one wing can provide some flight control capability if the lateral center of gravity can be shifted toward the side of the airplane that has the operating engine(s). Simulator tests of several airplanes with no flight control surfaces operating and all engines out on the left wing have all shown positive control capability within the available range of lateral center-of-gravity offset. Propulsion-controlled aircraft systems that can operate without modifications to engine control systems, thus allowing PCA technology to be installed on less capable airplanes or at low cost, are also desirable. Further studies have examined simplified 'PCA Lite' and 'PCA Ultralite' concepts in which thrust control is provided by existing systems such as auto-throttles or a combination of existing systems and manual pilot control.

Flight control actuation system

Science.gov (United States)

Wingett, Paul T. (Inventor); Gaines, Louie T. (Inventor); Evans, Paul S. (Inventor); Kern, James I. (Inventor)

2006-01-01

A flight control actuation system comprises a controller, electromechanical actuator and a pneumatic actuator. During normal operation, only the electromechanical actuator is needed to operate a flight control surface. When the electromechanical actuator load level exceeds 40 amps positive, the controller activates the pneumatic actuator to offset electromechanical actuator loads to assist the manipulation of flight control surfaces. The assistance from the pneumatic load assist actuator enables the use of an electromechanical actuator that is smaller in size and mass, requires less power, needs less cooling processes, achieves high output forces and adapts to electrical current variations. The flight control actuation system is adapted for aircraft, spacecraft, missiles, and other flight vehicles, especially flight vehicles that are large in size and travel at high velocities.

X-ray topography and multiple diffraction

International Nuclear Information System (INIS)

Chang, S.-L.

1983-01-01

A short summary on X-ray topography, which is based on the dynamical theory of X-ray diffraction, is made. The applications and properties related to the use of the multiple diffraction technique are analized and discussed. (L.C.) [pt

IXV re-entry demonstrator: Mission overview, system challenges and flight reward

Science.gov (United States)

Angelini, Roberto; Denaro, Angelo

2016-07-01

The Intermediate eXperimental Vehicle (IXV) is an advanced re-entry demonstrator vehicle aimed to perform in-flight experimentation of atmospheric re-entry enabling systems and technologies. The IXV integrates key technologies at the system level, with significant advancements on Europe's previous flying test-beds. The project builds on previous achievements at system and technology levels, and provides a unique and concrete way of establishing and consolidating Europe's autonomous position in the strategic field of atmospheric re-entry. The IXV mission and system objectives are the design, development, manufacturing, assembling and on-ground to in-flight verification of an autonomous European lifting and aerodynamically controlled reentry system, integrating critical re-entry technologies at system level. Among such critical technologies of interest, special attention is paid to aerodynamic and aerothermodynamics experimentation, including advanced instrumentation for aerothermodynamics phenomena investigations, thermal protections and hot-structures, guidance, navigation and flight control through combined jets and aerodynamic surfaces (i.e. flaps), in particular focusing on the technologies integration at system level for flight. Following the extensive detailed design, manufacturing, qualification, integration and testing of the flight segment and ground segment elements, IXV has performed a full successful flight on February 11th 2015. After the launch with the VEGA launcher form the CSG spaceport in French Guyana, IXV has performed a full nominal mission ending with a successful splashdown in the Pacific Ocean. During Flight Phase, the IXV space and ground segments worked perfectly, implementing the whole flight program in line with the commanded maneuvers and trajectory prediction, performing an overall flight of 34.400 km including 7.600 km with hot atmospheric re-entry in automatic guidance, concluding with successful precision landing at a distance of ~1

Evolution of diffraction and self-diffraction phenomena in thin films of Gelite Bloom/Hibiscus Sabdariffa

Science.gov (United States)

Cano-Lara, Miroslava; Severiano-Carrillo, Israel; Trejo-Durán, Mónica; Alvarado-Méndez, Edgar

2017-09-01

In this work, we present a study of non-linear optical response in thin films elaborated with Gelite Bloom and extract of Hibiscus Sabdariffa. Non-linear refraction and absorption effects were studied experimentally (Z-scan technique) and numerically, by considering the transmittance as non-linear absorption and refraction contribution. We observe large phase shifts to far field, and diffraction due to self-phase modulation of the sample. Diffraction and self-diffraction effects were observed as time function. The aim of studying non-linear optical properties in thin films is to eliminate thermal vortex effects that occur in liquids. This is desirable in applications such as non-linear phase contrast, optical limiting, optics switches, etc. Finally, we find good agreement between experimental and theoretical results.

Neutron diffraction studies on Ca1− xBaxZr4P6O24 solid solutions

Indian Academy of Sciences (India)

P6O24 compositions from combined Rietveld refinements of powder X-ray and neutron diffraction data. All the studied compositions crystallize in rhombohedral lattice (space group R-3 No. 148). A continuous solid solution is concluded from ...

Foraging in an unsteady world: bumblebee flight performance in field-realistic turbulence.

Science.gov (United States)

Crall, J D; Chang, J J; Oppenheimer, R L; Combes, S A

2017-02-06

Natural environments are characterized by variable wind that can pose significant challenges for flying animals and robots. However, our understanding of the flow conditions that animals experience outdoors and how these impact flight performance remains limited. Here, we combine laboratory and field experiments to characterize wind conditions encountered by foraging bumblebees in outdoor environments and test the effects of these conditions on flight. We used radio-frequency tags to track foraging activity of uniquely identified bumblebee ( Bombus impatiens ) workers, while simultaneously recording local wind flows. Despite being subjected to a wide range of speeds and turbulence intensities, we find that bees do not avoid foraging in windy conditions. We then examined the impacts of turbulence on bumblebee flight in a wind tunnel. Rolling instabilities increased in turbulence, but only at higher wind speeds. Bees displayed higher mean wingbeat frequency and stroke amplitude in these conditions, as well as increased asymmetry in stroke amplitude-suggesting that bees employ an array of active responses to enable flight in turbulence, which may increase the energetic cost of flight. Our results provide the first direct evidence that moderate, environmentally relevant turbulence affects insect flight performance, and suggest that flying insects use diverse mechanisms to cope with these instabilities.

Flight Deck Weather Avoidance Decision Support: Implementation and Evaluation

Science.gov (United States)

Wu, Shu-Chieh; Luna, Rocio; Johnson, Walter W.

2013-01-01

Weather related disruptions account for seventy percent of the delays in the National Airspace System (NAS). A key component in the weather plan of the Next Generation of Air Transportation System (NextGen) is to assimilate observed weather information and probabilistic forecasts into the decision process of flight crews and air traffic controllers. In this research we explore supporting flight crew weather decision making through the development of a flight deck predicted weather display system that utilizes weather predictions generated by ground-based radar. This system integrates and presents this weather information, together with in-flight trajectory modification tools, within a cockpit display of traffic information (CDTI) prototype. that the CDTI features 2D and perspective 3D visualization models of weather. The weather forecast products that we implemented were the Corridor Integrated Weather System (CIWS) and the Convective Weather Avoidance Model (CWAM), both developed by MIT Lincoln Lab. We evaluated the use of CIWS and CWAM for flight deck weather avoidance in two part-task experiments. Experiment 1 compared pilots' en route weather avoidance performance in four weather information conditions that differed in the type and amount of predicted forecast (CIWS current weather only, CIWS current and historical weather, CIWS current and forecast weather, CIWS current and forecast weather and CWAM predictions). Experiment 2 compared the use of perspective 3D and 21/2D presentations of weather for flight deck weather avoidance. Results showed that pilots could take advantage of longer range predicted weather forecasts in performing en route weather avoidance but more research will be needed to determine what combinations of information are optimal and how best to present them.

Aurora Flight Sciences' Perseus B Remotely Piloted Aircraft in Flight

Science.gov (United States)

1998-01-01

A long, slender wing and a pusher propeller at the rear characterize the Perseus B remotely piloted research aircraft, seen here during a test flight in June 1998. Perseus B is a remotely piloted aircraft developed as a design-performance testbed under NASA's Environmental Research Aircraft and Sensor Technology (ERAST) project. Perseus is one of several flight vehicles involved in the ERAST project. A piston engine, propeller-powered aircraft, Perseus was designed and built by Aurora Flight Sciences Corporation, Manassas, Virginia. The objectives of Perseus B's ERAST flight tests have been to reach and maintain horizontal flight above altitudes of 60,000 feet and demonstrate the capability to fly missions lasting from 8 to 24 hours, depending on payload and altitude requirements. The Perseus B aircraft established an unofficial altitude record for a single-engine, propeller-driven, remotely piloted aircraft on June 27, 1998. It reached an altitude of 60,280 feet. In 1999, several modifications were made to the Perseus aircraft including engine, avionics, and flight-control-system improvements. These improvements were evaluated in a series of operational readiness and test missions at the Dryden Flight Research Center, Edwards, California. Perseus is a high-wing monoplane with a conventional tail design. Its narrow, straight, high-aspect-ratio wing is mounted atop the fuselage. The aircraft is pusher-designed with the propeller mounted in the rear. This design allows for interchangeable scientific-instrument payloads to be placed in the forward fuselage. The design also allows for unobstructed airflow to the sensors and other devices mounted in the payload compartment. The Perseus B that underwent test and development in 1999 was the third generation of the Perseus design, which began with the Perseus Proof-Of-Concept aircraft. Perseus was initially developed as part of NASA's Small High-Altitude Science Aircraft (SHASA) program, which later evolved into the ERAST

Theoretical review of diffractive phenomena

International Nuclear Information System (INIS)

Golec-Biernat, K.

2005-01-01

We review QCD based descriptions of diffractive deep inelastic scattering emphasising the role of models with parton saturation. These models provide natural explanation of such experimentally observed facts as the constant ratio of σ diff /σ tot as a function of the Bjorken variable x, and Regge factorization of diffractive parton distributions. The Ingelman-Schlein model and the soft color interaction model are also presented

Bragg diffraction of fermions at optical potentials

International Nuclear Information System (INIS)

Deh, Benjamin

2008-01-01

This thesis describes the Bragg diffraction of ultracold fermions at an optical potential. A moving optical lattice was created, by overlaying two slightly detuned lasers. Atoms can be diffracted at this lattice if the detuning fulfills the Bragg condition for resting atoms. This Bragg diffraction is analyzed systematically in this thesis. To this end Rabi oscillations between the diffraction states were driven, as well in the weakly interacting Bragg regime, as in the strongly interacting Kapitza-Dirac regime. Simulations, based on a driven two-, respectively multilevel-system describe the observed effects rather well. Furthermore, the temporal evolution of the diffracted states in the magnetic trapping potential was studied. The anharmonicity of the trap in use and the scattering cross section for p-wave collisions in a 6 Li system was determined from the movement of these states. Moreover the momentum distribution of the fermions was measured with Bragg spectroscopy and first signs of Fermi degeneracy were found. Finally an interferometer with fermions was build, exhibiting a coherence time of more than 100 μs. With this, the possibility for measurement and manipulation of ultracold fermions with Bragg diffraction could bee shown. (orig.)

When fast atom diffraction turns 3D

International Nuclear Information System (INIS)

Zugarramurdi, Asier; Borisov, Andrei G.

2013-01-01

Fast atom diffraction at surfaces (FAD) in grazing incidence geometry is characterized by the slow motion in the direction perpendicular to the surface and fast motion parallel to the surface plane along a low index direction. It is established experimentally that for the typical surfaces the FAD reveals the 2D diffraction patterns associated with exchange of the reciprocal lattice vector perpendicular to the direction of fast motion. The reciprocal lattice vector exchange along the direction of fast motion is negligible. The usual approximation made in the description of the experimental data is then to assume that the effective potential leading to the diffraction results from the averaging of the 3D surface potential along the atomic strings forming the axial channel. In this work we use full quantum wave packet propagation calculations to study theoretically the possibility to observe the 3D diffraction in FAD experiments. We show that for the surfaces with large unit cell, such as can be the case for reconstructed or vicinal surfaces, the 3D diffraction can be observed. The reciprocal lattice vector exchange along the direction of fast motion leads to several Laue circles in the diffraction pattern

Flight Testing an Iced Business Jet for Flight Simulation Model Validation

Science.gov (United States)

Ratvasky, Thomas P.; Barnhart, Billy P.; Lee, Sam; Cooper, Jon

2007-01-01

A flight test of a business jet aircraft with various ice accretions was performed to obtain data to validate flight simulation models developed through wind tunnel tests. Three types of ice accretions were tested: pre-activation roughness, runback shapes that form downstream of the thermal wing ice protection system, and a wing ice protection system failure shape. The high fidelity flight simulation models of this business jet aircraft were validated using a software tool called "Overdrive." Through comparisons of flight-extracted aerodynamic forces and moments to simulation-predicted forces and moments, the simulation models were successfully validated. Only minor adjustments in the simulation database were required to obtain adequate match, signifying the process used to develop the simulation models was successful. The simulation models were implemented in the NASA Ice Contamination Effects Flight Training Device (ICEFTD) to enable company pilots to evaluate flight characteristics of the simulation models. By and large, the pilots confirmed good similarities in the flight characteristics when compared to the real airplane. However, pilots noted pitch up tendencies at stall with the flaps extended that were not representative of the airplane and identified some differences in pilot forces. The elevator hinge moment model and implementation of the control forces on the ICEFTD were identified as a driver in the pitch ups and control force issues, and will be an area for future work.

Flight research and testing

Science.gov (United States)

Putnam, Terrill W.; Ayers, Theodore G.

1989-01-01

Flight research and testing form a critical link in the aeronautic research and development chain. Brilliant concepts, elegant theories, and even sophisticated ground tests of flight vehicles are not sufficient to prove beyond a doubt that an unproven aeronautical concept will actually perform as predicted. Flight research and testing provide the ultimate proof that an idea or concept performs as expected. Ever since the Wright brothers, flight research and testing were the crucible in which aeronautical concepts were advanced and proven to the point that engineers and companies are willing to stake their future to produce and design aircraft. This is still true today, as shown by the development of the experimental X-30 aerospace plane. The Dryden Flight Research Center (Ames-Dryden) continues to be involved in a number of flight research programs that require understanding and characterization of the total airplane in all the aeronautical disciplines, for example the X-29. Other programs such as the F-14 variable-sweep transition flight experiment have focused on a single concept or discipline. Ames-Dryden also continues to conduct flight and ground based experiments to improve and expand the ability to test and evaluate advanced aeronautical concepts. A review of significant aeronautical flight research programs and experiments is presented to illustrate both the progress being made and the challenges to come.

Zeno dynamics in wave-packet diffraction spreading

Energy Technology Data Exchange (ETDEWEB)

Porras, Miguel A. [Departamento de Fisica Aplicada, Universidad Politecnica de Madrid, Rios Rosas 21, ES-28003 Madrid (Spain); Luis, Alfredo; Gonzalo, Isabel [Departamento de Optica, Facultad de Ciencias Fisicas, Universidad Complutense, ES-28040 Madrid (Spain); Sanz, Angel S. [Instituto de Fisica Fundamental-CSIC, Serrano 123, ES-28006 Madrid (Spain)

2011-11-15

We analyze a simple and feasible practical scheme displaying Zeno, anti-Zeno, and inverse-Zeno effects in the observation of wave-packet spreading caused by free evolution. The scheme is valid both in spatial diffraction of classical optical waves and in time diffraction of a quantum wave packet. In the optical realization, diffraction spreading is observed by placing slits between a light source and a light-power detector. We show that the occurrence of Zeno or anti-Zeno effects depends just on the frequency of observations between the source and detector. These effects are seen to be related to the diffraction mode theory in Fabry-Perot resonators.

Non-diffractive optically variable security devices

NARCIS (Netherlands)

Renesse, R.L. van

1991-01-01

At the past optical security conferences attention was focused on diffractive structures, e.g. holograms, embossed gratings and thin—film devices, as security elements on valuable documents. The main reasons for this emphasis are, that the iridescent effect of such diffractive optically variable

Hard diffraction and small-x

International Nuclear Information System (INIS)

Anon.

1995-01-01

In the United States, phrases such as ''small-x evolution'', ''the BFKL Pomeron'', ''deep-inelastic rapiditygap events'' and ''hard-diffraction'' do not generate the same intensity of discussion amongst high-energy physicists that they do in Europe. However, for three days in the fall such discussion filled the air at Fermilab. The ''2nd Workshop on Small-x and Diffractive Physics at the Tevatron'' was a review of the rapid theoretical and experimental progress taking place in this field. Although Quantum Chromo-dynamics (QCD) has been established as the theory of strong interactions for twenty years, as yet neither perturbative high-energy calculations nor low-energy non-perturbative techniques have been successfully extended to the mixture of high energy and low transverse momenta which characterize traditional ''soft'' diffractive processes. The simplest soft diffractive process is elastic scattering. In this case it is easiest to accept that there is an exchanged ''pomeron'', which can be pictured as a virtual entity with no electric charge or strong charge (colour), perhaps like an excitation of the vacuum. The same pomeron is expected to appear in all diffractive processes. Understanding the pomeron in QCD is a fundamental theoretical and experimental challenge. In the last two or three years the ''frontier'' in this challenging area of QCD has been pushed back significantly in both theory and experiment. Progress has been achieved by studying the evolution of hard collisions to relatively smaller constituent momenta (small x) and by studying ''hard'' diffractive collisions containing simultaneous signatures of diffraction and hard perturbative processes. The hard processes have included high transverse momentum jet production, deep inelastic lepton scattering, and (most recently) W

Multibreather solitons in the diffraction managed NLS equation

International Nuclear Information System (INIS)

Panayotaros, Panayotis

2006-01-01

We study analytically and numerically localized breather solutions in the averaged discrete nonlinear Schroedinger equation (NLS) with diffraction management, a system that models coupled waveguide arrays with periodic diffraction management geometries. Localized breathers can be characterized as constrained critical points of the Hamiltonian of the averaged diffraction managed NLS. In addition to local extrema, we find numerically more general solutions that are saddle points of the constrained Hamiltonian. An interesting class of saddle points are 'multi-bump' solutions that are close to superpositions of translates of simpler breathers. In the case of zero residual diffraction and small diffraction management, the existence of multibumps can be shown rigorously by a continuation argument

Diffraction analysis of customized illumination technique

Science.gov (United States)

Lim, Chang-Moon; Kim, Seo-Min; Eom, Tae-Seung; Moon, Seung Chan; Shin, Ki S.

2004-05-01