bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electro-Optical Systems for Dynamic Display of X-ray Diffraction Images
Authors: Green Robert E. 
Published: March 2019

AbstractVarious electro-optical systems have been reported which permit intensification of X-ray diffraction patterns and thus a decrease in exposure time for recording and display of the X-ray images. Prior to 1966, all such electro-optical systems incorporated a large format X-ray image intensifier of the same type as conventionally used for medical and industrial fluoroscopy. In the past four years, a number of different systems have been reported which are superior to those developed prior to 1966. These systems may be grouped into two main categories, the large format variety for Laue diffraction applications, and the small format variety for topographic applications.The purpose of the present paper is to describe the particular characteristics of both the large format and small format systems and to discuss the advantages and disadvantages associated with each type. Based on actual performance characteristics it will be shown that:1.A multiple stage image intensifier system coupled to an external fluorescent screen is the most sensitive and only truly instantaneous system; it can be used with very weak X-ray intensities, the resolution is currently limited by the external fluorescent screen to 42μ the system is extremely versatile in that it can be used both for large format recording of Laue patterns as well as for small format recording of X-ray topographe; the system has a very long lifetime since nothing is altered by X-radiation.2.An X-ray sensitive vidicon is the least sensitive; it must be used with extremely high intensity X-rays or long exposure times; the resolution is the highest at approximately 15μ and is limited by either bandwidth of the television system, the thickness of the X-ray sensitive target or the size of the electron beam at the target; due to the small size of the X-ray sensitive target the system can only be used for small format recording of X-ray topographs; the lifetime of the system is short since X-radiation causes degradation of the target.
X-ray Measurements of Surface Residual Stresses in Cold Rolled α-Brass
Authors: Wallace W. , Terada T. 
Published: March 2019

AbstractResidual elastic stresses have been measured in cold rolled α-brass (30% zinc) using the available x-ray diffractometer methods. Residual stress values obtained by the two exposure and sin2ψ methods of stress analysis are compared with data obtained using Wagner's extrapolation method.For deformations up to 50% reduction in thickness, tensile surface stresses prevailed, and in most cases could be detected by these methods. Uncertainty of the value of a0, the lattice parameter of the deformed' material, presents a serious limitation to the extrapolation technique. Using the approximation a0 = a0ann, residual stresses appear lower than, and frequently of opposite sign to those given by the two exposure method. In addition, lattice parameter variations in the near surface regions of the rolled sheet were opposite to those expected from the true macrostress distributions shown to exist by the two exposure method and by strain gauge techniques. The distributions of ahkl points in the extrapolation plots were in agreement with theory for a combination of anisotropic elastic stresses and low stacking fault density.
Characterization of PZT Thin Films Crystallographic Phases
Authors: Goehner Raymond P. , Eatough Michael O. , Tuttle Bruce A. , Headley Thomas J. 
Published: March 2019

AbstractThe use of grazing incidence parallel beam x-ray diffraction (GIXRD) in the characterization of lead zirconate titanate (PZT) films is described. This tool has enabled us to depth profile the films. The transmission electron microscopy (TEM) results obtained from a cross section of one film are shown to compliment the GIXRD results. The variation in crystallographic structure versus depth in the film was the primary focus of this study.The insults from three PZT films having Zr/Ti ratios of 25/75, 48/52, and 75/25 are given. TEM results are reported from the sample with a Zr/Ti ratio of 48/52.
X-Ray Diffraction Studies on Laminated Magnetic Recording Media
Authors: Gorman Grace L. , Yogi Tadashi , Lambert Steven P. , Alvarez David P. 
Published: March 2019

AbstractWe have studied a series of laminated thin films by x-ray diffraction to correlate their structural and magnetic properties. Previous works have shown that the signal-to-noise characteristics of laminated magnetic films with non-magnetic interlayers can exceed that of single layer magnetic films. In the case where the magnetic layer is known to have low signal-to-noise performance, the signal has been observed to increase as the number of layers whereas the noise increases as the square root of the number of layers. This yields a net improvement of the signal-to-noise ratio, making the overall film more attractive as a magnetic recording medium. In this paper, we investigate films which are laminated layers of magnetic CoPtCr and non-magnetic Cr. The films were deposited with sputtering parameters that generally give low noise characteristics in single layer films. Up to four layers of CoPtCr films were made with Cr spacer layers of 2 nm. We observe some improvement in signal-to-noise characteristics and reduction in coercivity. X-ray diffraction analysis shows that the crystallographic c-axis, which corresponds to the magnetic easy axis, becomes more preferentially oriented perpendicular to the film plane with each additional layer. This change in preferred orientation is consistent with the reduced in-plane coercivity of the film. In the double CoPtCr layer with one Cr spacer layer experiment, we see that as the Cr spacer layer is increased from 0.5 to 8 nm, the c-axis of the CoPtCr again becomes more preferentially oriented out of the film plane, resulting in decreased in-plane coercivity. The media signal-to-noise improves once the Cr spacer layer is beyond 2 nm, consistent with previous observations.
Characterization of Lattice Defects and Concomitant Strain Distribution
Authors: Weissmann Sigmund 
Published: March 2019

AbstractA number of X-ray methods characterizing lattice defects are described. They were developed in response to a variety of challenging problems in materials science, A method based on a computer-aided rocking curve analysis, CARCA, was developed which offers a rapid mapping of the dislocation structure in an epitaxial film, as well as a tensor analysis of nonuniform elastic strains. Characterization methods were developed in an attempt at bridging, systematically, the gap between micro and macromechanics when the problem arose to clarify the distribution of elastic strains emanating from stress concentrators such as notches, cracks, holes and to elucidate strain interactions. Gradients of elastic strains were characterized by a method of local intensity measurements. For crystal with homogeneous elastic strain distribution a tensor analysis is described, based on precision measurements obtained by the backreflection divergent beam method. A direct linkage between the imaging of the micro structure by TEM and the macro-response of deformation and recovery of commercial alloys was achieved by a version of the CARCA method, designed to characterize the lattice defects in polycrystalline materials. Example applications of the methods are presented with the hope that their usefulness may find adaptations in other areas of investigation.
Accurate Determination of Unit-Cell Parameters using Conventional X-Ray Powder Diffractometry
Authors: Toraya Hideo , Parrish William 
Published: March 2019

AbstractA procedure for the accurate determination of unit-cell parameters using conventional Xray powder diffractometry is described. Two important factors in the procedure are: 1) the use of high-resolution-type diffractometer, which can suppress the axial beam divergence and thus gives nearly symmetric diffraction profiles in the low 2θ region and 2) the use of a new algorithm for systematic peak shift correction during the least-squares determination of unit-cell parameters of a sample with an internal standard [Toraya & Kitamura (1990). J. Appl. Cryst. 23 , 282-285]. The procedure has been tested by measuring successively the unit-cell parameter of W, CeO2, and Si in three mixtures, Si+W, W+CeO2, and CeO2+Si: the unit-cell parameter of W, which was first determined by using NIST SRM 640b Si powder as an internal standard reference material, was used as a standard reference value to determine the unit-cell parameter of CeO; in the next W+CeO2 mixture, and so on. The difference between the end value of observed Si unit-cell parameters and the starting value of 5.430940(35) Å were just 1 to 5 p.p.m. High accuracy is attainable in measuring the uni-cell parameters even with the conventional powder diffractometry provided with the nearly symmetric diffraction profile and the algorithm for peak shift correction used in the present study.
HFIT, A Program for Interactive Analysis of Powder Diffraction Data
Authors: Will G. , Höffner Ch. 
Published: March 2019

AbstractHFIT is a program for the analysis of diffraction diagrams containing overlapping peak clusters. Profile functions have been implemented to analyze synchrotron diffraction data. It is written un Turbo C++ for PC operations. The analysis is done by operator interaction. The analysis is done on sections of the diffractogram containing a maximum of 2048 data points or 100 diffraction maxima. Special care is taken for smoothing the data and for the subtraction of background.
Determination of Dislocation Densities in Hexagonal Close-Packed Metals using X-Ray Diffraction and Transmission Electron Microscopy
Authors: Griffiths M. , Winegar J.E. , Mecke J.F. , Holt R.A. 
Published: March 2019

AbstractX-ray diffraction (XRD) line-broadening analysis has been used to determine dislocation densities in zirconium alloys with hexagonal closepacked (hep) crystal structures and a complex distribution of dislocations reflecting the plastic, anisotropy of the material. The validity of the technique has been assessed by comparison with direct measurements of dislocation densities in deformed polycrystalline and neutron-irradiated single crystal material using transmission electron microscopy (TEM). The results show that-there is good agreement between the XRD and TEM for measurements on the deformed material whereas there is a large discrepancy for measurements on the irradiated single crystal; the XRD measurements significantly underestimating the TEM observations.
Toroidal Monochromators in Hybrid XRF System Improve Effectiveness of EDXRF Tenfold
Authors: Furnas Thomas C. , Kuntz Gordon S. , Furnas Richard E. 
Published: March 2019

Our objectives in Instrument design & development are to improve the QUALITY OF THE DATA which can be obtained and presented to a computer system for analysis and to explore the corresponding choices which such improved data quality allows.In usual EDXRF systems, the detector views the entire scattered and fluorescence radiation from a sample illuminated either by a direct beam or by a secondary target. In either case, the beam may be filtered before it strikes the specimen. Most efforts to mono-chromatize the exciting radiation or to reduce the background under the fluorescent peaks from the sample result in (a) decreases in X-ray flux available for excitation, (b) significant increases in power expended in the X-ray tube, or (c) extremely close coupling of the system components. These are NOT THE ONLY CHOICES AVAILABLE.
"Standard-Background" Method of X-Ray Spectral Analysis for Quality Control of Noble Metals in Alumina-Based Automobile Exhaust Catalysts
Authors: Gurvich Yury M. 
Published: March 2019

Development of matrix correction procedures in the field of X-ray spectral analysis leads usually to “universal” algorithms which allow use of a common calibration equation for assay of various materials with different composition and concentration ranges. In many applications, such methods can guarantee accuracy of 3-5% rel.For X-ray analysis of automotive catalysts, one such technique is based on the theoretical correction of interelement effects. The article states that “the overall accuracy of this approach is about 10% relative error, although this may vary depending upon the particular specimen being analyzed.” However, narrow specification limits for the quality control of catalysts require the total error of analysis less than 1-1.5% rel.
A New Computer Algorithm for Qualitative X-Ray Powder Diffraction Analysis
Authors: Huang T. C. , Parrish W. 
Published: March 2019

AbstractAn effective and practical computer algorithm has been developed for rapid and precise phase identification of polycrystalline materials by X-ray diffraction methods using the JCPDS database and/or user created standard files. The entire JCPDS file was reorganized for efficient search. Identifications are facilitated by a number of options: automatic correction of systematic errors using internal standard reflections, selectable window widths for file searching, elemental restrictions (chemical prescreening), handling preferred orientation, match without using intensities, match with 3 reflections, and others. A comprehensive algorithm for calculating a figure-of-merit (FOM) is used so that the “correct” phases can easily be identified with highest FOMs. This method has been tested extensively on a wide variety of analyses and is applicable to either a host or a minicomputer.
INDEX, A Program to Reconcile Powder Diffractograms
Authors: Horn Tommy , Jenkins Ron , Ladell Joshua 
Published: March 2019

AbstractThis paper describes an interactive computer program, INDEX, which was written at Philips Laboratories as part of the software development effort for the APD 3600: Automated Powder Diffractometer. This program reconciles the differences between calculated and observed powder diffractogram “d-spacings” by unit cell parameters refinement and/or correction of observed lines for “significant“ systematic errors. The reconciliation procedures, described below, yield a set of residual differences which may be due to x-ray photon statistics, random gear imperfections, or minor instrumental aberrations. Lattice parameters accuracies of 4-5 parts per 104 can b e obtained routinely on powder diffractometers when systematic effects have been taken into account. The interactive nature of INDEX permits intervention at critical stages where it is most beneficial with a minimal number of keystrokes.
Comparison of Residual Stress Measurement and Breaking Strength on Alumina Rods
Authors: Snoha D. J. , Ruud C. O. , Cassel H. D. 
Published: March 2019

AbstractX-ray diffraction (XRD) utilizing copper K-alpha radiation and the single exposure technique (SET) was used for residual stress measurement on two different thermal treatments of Al-300 alumina rods. The measurements were performed in the axial and tangential directions on forty halves of twenty broken rods. The twenty rods were intially annealed for 8 hours at 1000°C; then ten were slow cooled and ten were equilibrated at 1450°C then force-air quenched. A fine mesh sapphire (alumina) powder was used as a zero stress standard for the determination of calibration validity of the position sensitive scintillation detector based (PSSD) stress measuring instrument used for this study. This instrument was developed at the Materials Research Laboratory of The Pennsylvania State University.
The Choice of Lattice Planes in X-Ray Strain Measurements of Single Crystals
Authors: Ortner Balder 
Published: March 2019

It is well known that all of the six independent components of the strain tensor can be calculated if the linear strains in six appropriate directions are known (e.g.). That calculation is to solve a system of linear equations, whose coefficients are defined by the orientations of the measured planes. The strains are determined by lattice plane distance measurements using X-rays.The linear equation system can only be solved if the matrix of coefficients has rank. Whether this condition is met or not can be decided without calculating a determinant just from geometric relationships among the planes to be measured. A demand beyond that necessary condition is to make the matrix of coefficients so that the accuracy of the calculated strain tensor is best. From error calculation we know that there exist distinct ratios between the inevitable measurement errors and the errors of the calculated strain components. These ratios depend strongly on the geometric relationship among the lattice planes. It is the purpose of this paper to show how lattice planes should be chosen in order to get these ratios as small as possible i.e. to get a maximum of accuracy at a given number of measurements, or a minimum of experimental effort if a distinct limit of error is to be reached.
Measurement of Elastic Lattice Distortion in PbTe/PbSnTe - Strained Layer Superlatices by Asymmetric High Angle X-ray interfernces
Authors: Fantner E. J. 
Published: March 2019

AbstractElastic strain significantly affects the electric and optical properties of PbTe/Pb1-xSnxTe - strained-layer superlattices. In the range of 10 - 350K the temperature dependence of the elastic strain present in these superlattices was measured by double-crystal x-ray diffraction. For superlattice periods smaller than 100nm High-angle x-ray interferences were observed. Using a novel method, which makes use of the High-angle interferences both for symmetrical as well as for asymmetrical reflections in a theta-twotheta scan with a narrow detector slit, the relative inclination of equivalent lattice planes due the elastic strain was measured. The components of the complete strain tensor of the constituent layers can be determined seperately even if their unstrained lattice constants are not known with sufficient accuracy as is the case in ternary and quaternary compounds. The lattice mismatch of up to 0.4% for Sn-contents smaller than 20% was found to be accommodated almost completely by elastic misfit strain. The amount of strain is shared between the constituent layers inversely to their relative thicknesses as long as the superlattice as a whole is much thicker than the buffer layer. Below room temperature an additional temperature dependent tensile strain due to differnt thermal expansion coefficients of the film and the BaF2-substrate is measured quantitatively.
Characterization of Tungsten Silicide and Titanium Silicide Thin Films With a Fully-Automated See Mann-Bohlin Diffractometer
Authors: Matyi R. J. 
Published: March 2019

The continuing drive in the semiconductor industry towards smaller and more complex electronic devices has placed increasing severe demands on the materials systems that are used in semiconductor circuits. The refractory metal silicides that are commonly used for electrodes and interconnects are particularly susceptible to the sometimes conflicting requirements of good electrical properties, ease of processing, and long term reliability. We have found that the characterization of metal silicides with a fully automated diffractometer based on the Seemann- Bohlin (S∼B) focusing geometry has proved to be an important aid in the development of several semiconductor metallization systems.Although a conventional Bragg-Brentano (B-B) diffractometer can provide adequate information for some thin film systems, the use of an S-B diffractometer in which the incident x-ray beam makes a very small angle of incidence with the sample surface results in a substantial improvement in the usable signal from very thin samples.
An X-Ray Micro-Fluorescence Analysis System With Diffraction Capabilities
Authors: Nichols M. C. , Ryon R. W. 
Published: March 2019

AbstractA prototype X-ray fluorescence system for chemical and phase microanalysis of materials has been developed and tested. Preliminary work with this system has indicated X-ray fluorescence detection limits on the order of 40 picograms for heavier elements such as gold when using a 100 micron collimator, 400 second counting time and a silver anode operating at 12 Kw. Phase identification by X- ray diffraction can be obtained from the same spot. A proposed design for an improved system providing greater elemental sensitivities and capable of semi-automated operation has been completed.
On-Stream Analysis of Liquid Samples Containing Elements of High and Low Atomic Number by X-Ray Fluorescence With Air and Vacuum Spectrograph
Authors: Chan Frank L . 
Published: March 2019

Recently on-stream analysis by various methods and instruments has been greatly and rightfully emphasized. This is particularly true in such research as air and stream pollutions, desalting of ocean water and ore processing.Among the various methods, instruments, and procedures adopted, the X-ray fluorescence method is perhaps the best among them. This is because the x-ray fluorescence method neither consumes nor destroys the samples taken for analysis. It also has the merits of simplicity and specificity. However, on-stream analysis of liquid samples containing elements having an atomic number below 20 by the X-ray fluorescence method is not an easy task particularly when vacuum spectrograph is being used.In this study liquid cells of different dimensions for the on-stream analysis operated in air, helium and in vacuum have been successfully constructed. The cells have been tested for several months.
Study of the Precision of X-ray Stress Analysis
Authors: James M. R. , Cohen J. B. 
Published: March 2019

Software is described for complete computer control of residual stress measurements. One program (that incorporates either the two tilt method, the sins| procedure, or the Cohen-Marion technique) has been developed for use with either a normal detector or a position sensitive detector. The operator inputs the desired error in stress and various instrumental parameters that determine systematic errors. The counting strategy to obtain the total error is then determined by the software.Employing this automated system, an investigation of a parabolic fit to the top of a diffraction profile indicates that a three point fit is satisfactory only for sharp profiles.
Quantitative Analysis of Platelike Pigments by X-Ray Diffraction
Authors: Kamarchik P. , Ratliff J. 
Published: March 2019

X-ray diffraction has been shown to provide an accurate qualitative and quantitative determination of the pigment composition of paint films. This analysis, however, is frequently complicated by the presence of pigments with plate-like crystallites which show a marked tendency to orient in preferred directions in drying paint films. The variability in the degree of orientation causes line intensity variations not attributable to pigment concentration.A technique based on a summation of the intensities of many lines has been used to correct for the effects of preferred orientation in the analysis of retained austenite in certain steels. This method is shown to be applicable to the quantitative analysis of mica in paint films.
The Use of Multi-scan Diffraction in Phase Identification
Authors: Smith Gordon S. , Nichols M. C. 
Published: March 2019

AbstractPhase identification by X-ray diffraction techniques in a complex mixture would be greatly simplified if the component phases could be physically separated. As opposed to current computer search-match algorithms for phase identification, which presuppose a single diffraction scan on a carefully prepared sample, we propose multi-scan data-taking on a not-so-carefully prepared sample so as to exploit certain aberrations in the diffracted intensities. The result can effectively be a physical separation by diffraction. Examples include exploitation of samples having a preferentially oriented component as well as samples with components having differing crystallite sizes. The techniques can involve diffractometer as well as film techniques.