bluuebunny/crossref_metadata_2025_split huggingface dataset:
A High-Speed, Selective Uniform-Particle-Size Grinder for the Preparation of Analytical Samples
Authors: Pitchford A. H. 
Published: March 2019

AbstractUniformity of particle size is most critical iti both X-ray spectrographic and diffraction samples. This is especially true when there are both hard and soft materials in the sample. The soft material reduces to a smaller particle size and therefore presents a great density and area to the X-ray beam. Accurate quantitative determinations are most difficult under these clrcum s tances. This paper decribes a means of grinding to a more uniform particle size and presents graphic data on the effects of particle-size variation.
Determination of Zinc Sulfide and Cadmium Sulfide in Solid Solutions of Small Single Crystals Used for Semiconductors by X-Ray and Chemical Methods
Authors: Chan Frank L. 
Published: March 2019

AbstractSingle crystals of cadmium sulfide and zinc sulfide have been grown and studied intensively by the Solid State Physics group at the Aeronautical Research Laboratory. The physical phenomena such as reflection, transmission, ultraviolet-excited emission, and electrical resistivity have been observed and characterized on single crystals of these sulfides. Much interest concerning these phenomena has also been centered on single crystals containing both cadmium sulfide and zinc sulfide.For research purposes, mixed crystals as small as a few tenths of 1 mg or less, to 0.5 g of the mixed sulfides, are being prepared. Special chemical methods are required to determine these constituents in them quantitatively. At times, these chemical methods are not applicable, since these methods invariably consume the sample, and, as a result, other observations on the same crystals cannot be performed.Changes in lattice parameter in single crystals of mixed sulfides as compared to pure zinc sulfide or cadmium sulfide provide excellent means for the determination of the percentage of these sulfides. In the X-ray method, single crystals used for the determination of the lattice parameters remain intact. The equipment adopted, procedure used, and the data obtained are illustrated and discussed.In the present study, crystals of cadmium sulfide (greenockite), alpha-zinc sulfide (wurtzite) and solid solutions of these two sulfides having a hexagonal unit cell were used. Since the lattice parameter a0 is found to follow Vegard's law, single-crystal rotation photographs described in this paper were obtained by rotating crystals around the c axis; the lattice parameter was determined with high precision by scanning along the zero-layer line with a microphotometer.
Determination of Thermal Expansion by High-Temperature X-Ray Diffraction
Authors: Vaughan Dale A. , Schwartz Charles M. 
Published: March 2019

AbstractTwo high-temperature X-ray diffraction cameras are described which have been employed at Battelle to determine thermal expansion of metals and ceramic materials. Specimen preparation and temperature measurement and control are described. Lattice-parameter data vs. temperature are presented for uranium, uranium dioxide, and magnesium oxide.
Effect of Impurities on Kaolinite Transformations as Examined by High-Temperature X-Ray Diffraction
Authors: Wahl F.M. 
Published: March 2019

AbstractThe high-temperature continuous X-ray diffraction technique has been used at the University of Illinois for several years in our investigation of structural transformations and the development of phase minerals as natural materials are heated. Of particular interest are the effects which chemical impurities have on predicted structural transformations at elevated temperatures.The formation of mullite and beta-cristobalite as they develop from the clay mineral kaolinite is examined by continuous X-ray diffraction up to 1450°C, and the influence of added impurities either to enhance or to retard nucleation of these phase minerals is shown. The 2θ range containing diagnostic peaks of both the initial material and of the transition and phase minerals which develop on heating was continually traversed, thus providing a constant record for comparing structural changes vs. temperature.The furnace used is described in detail, and the effects of added impurities on kaolinite transformations are evaluated to show their importance in controlling the thermal history of a natural material under nonequilibrium conditions.
Projection Microscopy and Microanalyses*
Authors: Poen Ong Sing 
Published: March 2019

AbstractResults of recent experiments on microanalyses with an X-ray projection microscope will be reviewed. As the use of monochromatic radiation is imperative, spectral analyses of the point source were carried out. A simple stationary divergent-beam-type transmission spectrograph was used. The shape and size were miniaturized to fit in the specimen holder of the Norelco projection unit. Emission spectra from clean, targets and the fluorescent radiation emerging from a 10- to 50-μ-diameter spot of contaminated targets and of two-layer targets will be shown. The spectra were recorded photographically. In addition, a proportional counter, in combination with the R.C.L. 128-channel pulse-height analyzer, was used for measuring the ratio of “white” to line radiation.
Determination of Trace Elements in Plant Material by Fluorescent X-Ray Analysis
Authors: Lytle F.W. , Dye W.B. , Seim H. J. 
Published: March 2019

AbstractA method is presented for the determination of trace elements in plant materials. The samples were composed of organic material, which was eliminated by wet ashing, large amounts of group I and II elements, and many trace elements of interest in the concentration range 0.1–100 ppm. An attempt to achieve preconcentration of the trace elements by absorption on cation-exchange membrane (which could have been used directly for analysis) was unsuccessful because of preferential absorption and saturation of the membrane by group I and II cations. Formation of complex-metal anions in acid solution and absorption on anion-exchange resin was more successful, but, because of a lack of precision and incomplete absorption, the technique was inadequate. In the most successful preconcentration scheme, an organo-metallic precipitation was used in a matrix suitable for X-ray analysis. In this precipitate the elements Fe, Mn, Cu, Zn, Co, Mo, Cr, Ni, Ti, V, Ca, Sn, Sc, Ba, and Pb could be quantitatively determined. In many cases the lower limit of detection was 0.01 ppm. The accuracy and precision of the technique were proved by comparison to chemically analyzed samples, recovery experiments, and replicate analyses. The method is generally applicable for the analysis of many organic materials.
On the Use of a Modified Radial Distribution Analysis for Indexing Powder Patterns
Authors: Berndt A. F. 
Published: March 2019

AbstractA modification of the theory of X-ray radial distribution analysis is presented. This modification can serve as a guide to the values of the unit cell dimensions and may be useful in indexing powder patterns of unknown structures, although the use of trial and error methods is not eliminated. This technique is shown to give consistent results with known structures and is applied to the indexing of powder patterns of Pu3Ru and Pu5Ru3. The powder pattern of Pu3Ru can be indexed on the basis of an orthorhombic unit cell with a0 = 6.216 Å, b0 = 6.924 Å, and c0 = 8.093 Å, and Pu5Ru3 on the basis of a tetragonal unit cell with a0 = 8.092 Å and c0 - 10.023 Å.
X-Ray Diffraction Studies on the Titanium-Nickel System
Authors: Gilfrich John V. 
Published: March 2019

AbstractX-ray diffraction studies were made on the Ti–Ni system around the stoichiometric composition of the intermetallic compound TiNi to clarify some confusion which has existed about the phase diagram in this region, and to explain some anomalies in the physical properties of this material. Wrought and cast samples were examined at room temperature both before and after heat treatment and at temperatures both above and below ambient. The compound TiNi does exist at room temperature. The phase purity of the particular sample was found to be greatly affected by such factors as minor variations in composition, heat treatment, and method of sample preparation. Some confirming metallographlc and physical property data will also be presented.
The Crystal Structure of ThPd4
Authors: Thomson J. R. 
Published: March 2019

AbstractThe structure of ThPd4 has been determined by X-ray powder methods. It has the simple cubic Cu3Au (LI2) structure a = 4.110 ± 0.002 Å at 80 at. % palladium. Interatomic distances and the range of stability of this compound and of ThPd3 are discussed briefly.
The Characterization of Large Single Crystals by High-Voltage X-Ray Laue Photographs
Authors: Peiser H. S. , Levine E. P. 
Published: March 2019

AbstractLarge single crystals can be examined by conventional X-ray diffraction procedures only at their surface or by destructive sectioning. Within the limitations inherent in polychromatic X-ray photography, high-voltage Laue pictures arc shown to give some information on the internal quality of large crystals.Asterism in conventional Laue photographs is contrasted, with streaks due to geometric effects in Laue patterns of large crystals. Detail within the streaks reveals subgrain structure. A primary extinction effect can be used as striking proof of good crystals being capable of scattering coherently over large distances.
An X-Ray Determination of the Debyewaller Factors for Cu2O and UO2 and the Atomic Scattering Factor for Cu in Cu2O
Authors: Sparks C. J. , Borie B. S. 
Published: March 2019

AbstractThe Debye-Waller factor for CuaO and the atomic scattering factor for copper were determined independently of each other at one temperature from measurements of both the diffuse scattering and the integrated intensities of the Bragg maxima. The scattering factor agreed well with that computed from theory. The characteristic temperature computed from the Debye-Waller factor at 298°K was found to be 182°K. At 88°K its value is 152°K.Similar measurements of the Bragg maxima with a powder sample of UO2 were not useful because of preferred orientation. However, the diffuse intensity is not so sensitive to preferred orientation and may be used to determine the characteristic temperature. Its value for UO2 was found to be 188°K at room temperature.
An X-Ray Study of the Structure of the Alkaline Earth Oxide Cathode
Authors: Lublin Paul 
Published: March 2019

AbstractArt X-ray diffraction study has been conducted on the emissive coating (Ba, Sr, CaO) of experimental diodes from which thermionic emission data were taken before X-ray analysis. The tubes were then opened and the oxide protected by special techniques in order to prevent the formation of the hydroxide. In addition to X-ray diffraction, other techniques were used to give a complete description of the structures present.
Applicability of Routine Methods of Crystallite Size Analysis*
Authors: Rau Robert C. 
Published: March 2019

AbstractSeveral methods for the routine determination of crystallite size by means of X-ray diffraction line-broadening have previously been reported. Although these techniques have proven useful and reliable when utilized with the single X-ray diffractometer and instrumental geometry used to originally develop the methods, it was not known whether other instruments would provide similar reliability. Therefore a study was performed to evaluate the applicability of routine methods of crystallite size analysis to other X-ray diffraction units. A series of six beryllium oxide powder specimens, whose average crystallite sizes ranged stepwise from about 35 to nearly 3000 Å, were used to test a number of X-ray diffractometers. By using a predetermined diffraction geometry for each instrument tested, measured crystallite sizes were found to be quite reproducible and well within the limits of experimental error. The testing procedure, instrumental conditions, and individual performance results are presented in this paper.
The Preparation of Pole Figures for Polymers by Computer Techniques
Authors: Jones J. W. 
Published: March 2019

AbstractPreferred orientation in polymers has been studied by preparation of pole figures. The diffraction data are collected on punch tape under the control of a programmer for the orienter which permits step wise or continuous scanning. A computer is programmed to prepare the data for an off-line automatic curve plotter. Several projections are available.
Experiences of X-Ray Analyses in Steel and Ferro-Alloy Production
Authors: Baecklund J. 
Published: March 2019

AbstractA vesta Steel Works manufactures stainless steel, low-alloy steel, alloys for precision casting, welding electrodes, and ferro alloys. When it was decided in 1958 that a new laboratory for production control was to be built, there was an investigation into different spectrographic possibilities. A combination of X-ray and optical methods was selected, that is, determination of C, P, and S was to be made optically while Si, Ti, and heavier elements were to be determined on X-ray equipment. Specimen taking and specimen preparation techniques were worked out. Certain interelement effects were recorded and methods to correct for them found. Methods to. correct for surface properties in determination of high concentrations have been taken into use. This laboratory has now been in continuous use for more than two years. Statistical data on accuracy, reliability, and continuity of operation are given.
Sodium and Magnesium Fluorescence Analysis—Part II: Application to Silicates
Authors: Baird A. K. , McIntyre D. B. , Welday E. E. 
Published: March 2019

AbstractModerate counting rates, in excess of 400 cps at a signal/noise ratio of 18 on 3.5% NaaO in rocks, permit high-precision quantitative analysis for light elements in silicates. Special advantages of fluorescence analysis in the 10 A region, with adequate excitation provided by an aluminum target tube, will be described. These advantages include an ease of discrimination by excitation potential and by high dispersion using large 2d space crystals. Minor and simple modifications of the optic path combined with electronic discrimination make the method ideal for sodium and magnesium. Routine runs over periods of days have been made possible by a new technique of calibration involving computer corrections for systematic drift from any source. Repeated tests show that the total analytical error, including specimen preparation, closely approaches that of the counting statistics used, and that the drift corrections are complete. In granitic rod; analyses resulting precisions (standard deviation/mean) are 1% for 2-5% Na2O and 2% for 0.25-1.0% MgO.
Determination of Catalyst Residues in Polyolefins by X-Ray Emission Spectroscopy
Authors: Smith G. D. , Maute R. L. 
Published: March 2019

AbstractX-ray fluorescence methods for the direct determination of aluminum, chlorine, titanium, and iron in polyolefins have been developed. The procedures require no preconccntration of elements, are satisfactory for any polyolefin, and are free from matrix effects. The accuracy and precision are generally comparable with or better than chemical procedures. In addition, the speed of the analysis is six to eight times faster.
X-Ray Analysis of Mining and Mineral Processing Material
Authors: Dryer H. T. 
Published: March 2019

AbstractThe X-ray analysis of the materials associated with the mining and mineral processing industries offers a wide variety of potential applications and a challenge to the X-ray analyst. X-ray methods are rapid, reproducible and, when suitably applied, accurate for elements of atomic number 12 or greater. These characteristics make it an ideal process control system. In general, the materials for each type of process require individual analytical techniques to provide reliable analytical data. A wide variety of materials have been studied on the ARL Vacuum X-ray Quantometer and their performances evaluated. An evaluation of the sample preparation and analytical methods required are given.
Increasing the Versatility of the G. E. Diffractometer
Authors: Schwartz L. H. , Morrison L. A. , Cohen J. B. 
Published: March 2019

AbstractTo achieve increased case and precision of alignment, and to allow for convenient alteration between normal usage with filtered radiation and crystalmonochromated radiation, the G. E. goniometer has been mounted on milling machine beds allowing for x-y translation and 360° rotation; in addition the tube mount was repositioned. The usefulness of this apparatus has been demonstrated by accurately aligning the goniometer for usage with filtered radiation, with a new alignment procedure. As a demonstration of the accuracy and precision of alignment, the lattice parameter of silicon was determined from a powder sample. A least-squares analysis of the data gave a0 = 5.43046 Å with a standard deviation of ±0.00005 Å, in excellent agreement with the value of 5.43054 ± 0.00017 Å determined in a recent International Union of Crystallography test in many laboratories.A monochromator housing has been built for use with all types of direct-beam monochromators and all radiations. This apparatus attaches to the new tube mount and was used to determine the optimum procedure for preparing the doubly bent LiF monochromator crystals designed by Warren to minimize the volume sampled in the reciprocal space of a single crystal. According to a suggestion made by Chipman, a doubly bent monochromator for use with poly crystalline specimens has been formed and its geometry and applications are presented. This monochromator gives about one-half as much intensity as that obtainable using filtered radiation and similar operating conditions ; this type of monochromator is therefore a powerful tool for use with powder specimens. A transmission diffracted-beam monochromator has also been constructed which attaches in a simple manner under the counter tube housing. Under similar operating conditions with a LiF monochromator, this yields intensities only one-tenth of those obtained using filtered radiation.
An X-Ray Absorption Method for Elemental Analysis
Authors: Knapp K. T. , Lindahl R. H. , Mabis A. J. 
Published: March 2019

AbstractA new approach to X-ray absorption analysis is presented in this paper. The equation log (I2/I1) = KWA + KB is used, from which the weight fraction WA of a given element can be calculated in various solvents when only a calibration curve from one solvent and the absorption of the new solvent at two wavelengths (λ1 and λ2) are known.This treatment uses the absorption at two wavelengths, one on each side of an absorption edge of the element under study. The desired wavelengths can be conveniently obtained from the Kα and Kβ radiation of an element with an atomic number just higher than the element under study. An easy way to accomplish this is to use the desired target element as the sample in an X-ray spectrometer. The Kα and Kβ radiations are then resolved with an appropriate analyzing crystal, and the absorption measurements are made consecutively.The advantages of this approach are twofold. First, it is only necessary to do a full calibration curve in one solvent; calibration in other solvents can be calculated with only a knowledge of the absorption of that pure solvent at the wavelengths used, which can. either be determined experimentally or calculated. Secondly, the required experimental data can be collected very conveniently in an X-ray spectrometer.
Application of a Pulsed Soft X-Ray System to the Determination of Phosphor Response Characteristics
Authors: McCue James C. 
Published: March 2019

AbstractA compact, high-intensity pulsed soft X-ray system has been used to study the response characteristics of a plastic scintillation phosphor (NE-102). In particular, the decay characteristics of this phosphor plated on one surface with a thin (<1000 Å) layer of aluminum were investigated. Although, absolute calibration of the X-ray source had not been performed, estimates of X-ray scintillation efficiency were obtained, using two separate methods, which were in agreement to within a factor of two.The primary purpose of this cursory program was to establish the validity of transferring calibration data from plated to unplated NE-102 scintillators employed in a photometric recording system. The results of the ensuing investigation indicated the equivalence of the two, but revealed several interesting and unsuspected phenomena. These were (1) an apparent scintillation light reflectance component of zero from the plated aluminum “mirror” surface, (2) a change in pulse waveform from electron beam input to scintillation light output, and (3) a 90-nsec delay between electron beam and photomultiplier signals. The methods employed in obtaining and verifying these data are subject to errors from uncertainty in the characteristics of several components employed in the experimental setup. These uncertainties and other measurement errors caused independent estimates of the external scintillation light efficiency to range from 0.1 to 0.2 %.Other potential applications of a pulsed soft X-ray system to measurement problems in industry and research include dynamic studies in the fields of X-ray crystallography, instrumental methods of materials analysis, and radiography of low-density subjects.
The Use of a Portable X-Ray Unit for Measuring Residual Stresses in Aluminum, Titanium, and Steel Alloys
Authors: Bolstad Donald A. , Quist William E. 
Published: March 2019

AbstractThe principles of measuring surface stresses in metals by X-ray diffraction with commercially available equipment are well known. Two techniques of making stress measurement by X-ray diffraction now in general use are (1) X-ray diffractometer with electronic control panel and (2) back-reflection film camera.The X-ray diffractometer technique has a number of important advantages over the film method, the major ones being accuracy and speed, but serious size and shape limitations are imposed on the specimen by the equipment: Because of its bulk and weight, specimens must be brought to it. The Airplane Division of The Boeing Company has capitalized on the advantages offered by the mobile backreflection film technique, especially with regard to specimen sizes and shapes. Results and techniques used, at Boeing for stress measurements in alloys of aluminum, titanium, and steel are presented. Experimental difficulties are discussed, and comparisons are made between results from the dirfractometer and backreflection camera, A portable darkroom and electropolishing unit are also presented which, with the X-ray unit, comprise a completely mobile stress-measuring facility.
A Study of Defects Due to Surface Processing in Silicon by Means of X-Ray Extinction Contrast Topography
Authors: Meieran E. S. , Lemons K. E. 
Published: March 2019

AbstractIn order to study the effects of processing variables on the defect contents of silicon wafers, an X-ray extinction contrast camera was designed and constructed to fit on the standard GE XRD-5 table. The camera, in its normal operating position, can be routinely used without interfering with the emission or diffraction instrumentation of the unit, and also can be mounted on the diffractometer stage for diffraction line breadth analysis. Routine laboratory procedures including sample preparation and mounting, film types, and film exposure and development are outlined.The correlation between extinction contrast topographs and optical photographs of sawed wafers is presented. Wafers were examined in the sawed, lapped, and chemically polished conditions. Subsequent to each processing step in the surface treatment of wafers, a series of topographs was made using four different crystal orientations. In this manner the three-dimensional picture of the defects is obtained, as are the Burger's vectors of all dislocations. It appears that internal defects such as dislocations are more uniformly distributed in lapped and chemically polished wafers than in sawed and chemically polished wafers. Furthermore, different doping impurities and levels cause different amounts of contrast in the dislocation images.