bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enhanced Range of Measurable Thickness of Thin Crystalline Layers Using θ/2θ Decoupled Powder X-ray Diffraction
Authors: Kimmel G. , Kaplan W. 
Published: March 2019

X-ray diffraction is one of the most useful methods for the characterisation of thin crystalline layers or coatings. The most interesting techniques are: the identification of phases and their relative quantities, texture analysis, and residual stress measurements.Thin layers which are transparent to the x-ray beam (in the diffracted wavelength) yield different intensities as compared with a bulk sample.
X-ray Residual Stress Analysis of Zn-Ni Alloy Electroplating Layers
Authors: Sasaki Toshihiko , Kuramoto Makoto , Yoshioka Yasuo 
Published: March 2019

Zn-Ni-alloy electroplated steels are one of the surface-treated materials with a high corrosion resistance and are mostly used for automobiles. It is said that the corrosion resistance is more than four times as great as that of Zn-plated steels. Concerning x-ray stress measurement, Kyono et al reported the result of measurement on y (552) planes and showed that the sin2φ diagram was severely curved.X-ray stress analysis in surface-treated materials will become more important. Some problems, however, remain to be studied when we apply the x-ray method to thin layers. For example, the effective x-ray penetration depth may be different from that in ordinary materials. And complex gradients of stresses and compositions may exist.
X-ray Powder Diffraction QPA by Rietveid Pattern- Fitting - Scope and Limitations
Authors: O'Cannar B.H. , Deyu Li , Jordan B. , Raven M. D. , Fazey P. G. 
Published: March 2019

AbstractThe X-ray Analytical Science Group at Curtin university of Technology has been developing and evaluating Rietveld pattern-fitting for materials analysis since 1985. The results are reviewed with particular reference to preferred orientation, crystallinity and phase abundance.
Problems in the Derivation of d-Values from Experimental Digital XRD Patterns
Authors: Jenkins Ron , Nichols Monte 
Published: March 2019

AbstractMost commercially available, automated powder diffractometers include software packages for the determination of d-values from experimentally recorded digitized patterns. While many of these patterns offer great flexibility to the user, indications from a recent Round-Robin Study [1] are that many users are confused as to the correct use of such parameters as choice of step size and counting time, the degree of data smoothing, peak-hunting parameters, setting of background level, and the consequences of background subtraction and α2 stripping. This paper will reviews these various factors and give some guidelines as to the establishment of optimum conditions.
X-ray Analysis of the Structure of Wholly Aromatic Copolyamides and Copolyester Carbonates
Authors: Schneider A.-I. , Blackwell J. 
Published: March 2019

AbstractThis paper summarizes our work on the structures of two wholly aromatic copolymers: the copolyamide prepared from terephthalic acid, phenylene diamine, and 3,4'-diaminodiphenyl ether (mole ratio 50/25/25) and the copolyester carbonate prepared from p-hydroxy benzoic acid and hydroquinone, with the introduction of carbonate units (mole ratio 60/20/20). X-ray fiber diagrams of both copolymers exhibit a number of aperiodic meridional maxima that are similar to those reported for a series of wholly aromatic copolyesters. The latter systems have been shown to consist of arrays of parallel chains of completely random comonomer sequence: the aperiodic maxima arise due to structural correlations along the extended random sequences. The structures studied in the present paper are more complex due to the presence of kinked units, i.e. the 1,3 phenylenes and ether linkages of the copolyamide, and the carbonate groups of the copolyester carbonate. The results obtained show that the x-ray data can be explained by completely random monomer sequences. However, the chains are significantly distorted in order to produce more extended conformations than might be expected for isolated chains. These distortions minimize the effects of the kinked units and lead to better chain packing.
Phase Diagram Studies on Neopentylglycol and Pentaerythritol-Thermal Energy Storage Materials
Authors: Chandra Dhanesh , Lynch Renee A. , Ding Wei , Tomlinson John J. 
Published: March 2019

AbstractPentaerythritol (PE) and neopentylglycol (NPG) are organic molecular crystals which have hydrogen-bonded lattices with layered- and chain-type structures, respectively. The PE undergoes solid-state phase transitions at 416K, from tetragonal to a cubic (γ’) structure and NPG also undergoes this transition at 317K from a monoclinic to a cubic (γ) structure. The phase transitions in binary PE-NPG solid solutions show more than one solid-solid transition in which the NPG-rich β transforms to γ at a constant temperature but the transition of the PE-rich a phase to γ’ passes through a two-phase field at a temperature that varies as a function of composition. Structural analyses by high-temperature x-ray diffractometry have revealed some new, interesting transitions. A phase diagram has been constructed for 0-30 mol% NPG in the PE-NPG system, using x-ray diffraction and differential scanning calorimetry results, and work is in progress to complete this diagram. The variation of lattice parameters as a function of temperature in the α, γ and γ’ phases for PE+20 mol% NPG are presented here, together with a discussion of phase transitions for certain compositions.
Qualitative XRF Analysis with Pattern Recognition
Authors: Yin Lo. I. , Seltzer Stephen M. 
Published: March 2019

AbstractIn many applications of energy-dispersive XRF analysis, quantitative information concerning the chemical composition of the samples is not required. Rather, one is interested in whether a given sample is similar to some reference material or whether the chemical composition is changing from one sample to the next. We have investigated the use of pattern-recognition techniques in such applications. It will be demonstrated with experimental data that the pattern-recognition approach is extremely simple and fast. It uses only a single parameter, the normalized correlation coefficient, and can be applied directly to raw data. The efficacy of the method is illustrated with Si(Li) spectra of geological and pigment samples, and proportional counter spectra of geological samples. The pattern-recognition method should be ideally suited for field XRF applications, and the algorithm can be easily implemented on a personal computer.
Process Control Applications of the Peltier Cooled SI (LI) Detector Based EDXRF Spectrometer
Authors: Harding Anthony R. 
Published: March 2019

AbstractThe demand for on-line analyzers capable of compositional determinations in petroleum and chemical process streams has increased dramatically in recent years. Total control of production plant processes and resources requires the analysis of feed, intermediate, and product materials. This paper will describe a rugged, on-stream energy dispersive X-ray fluorescence (EDXRF) analyzer configured for the continuous determination of composition in solid and liquid samples. The detector in the X-ray sensor is a lithium-drifted silicon crystal which is thermoelectrically cooled (Peltier effect) to achieve operational temperatures. This approach to detector cooling offers advantages over traditional cryogenic liquid cooling when EDXRF is used in the process control environment.Three applications of the thermoelectrically-cooled detector-based EDXRF spectrometer will be presented here. The first is the analysis of a catalyst solution to monitor depletion of the active species. Second, two components of a plating bath solution will be determined simultaneously in a flowing sample stream. In the third application, the spectrometer will be oriented in a downward looking configuration to monitor inorganic constituents in absorbent samples as they are transported by conveyor belt to the X-ray measurement area.
Concepts of Influence Coefficients in XRF Analysis and Calibration
Authors: Rousseau Richard M. 
Published: March 2019

AbstractIt will be shown that there are different types of influence coefficients to correct for matrix effects in XRF analysis: the empirical coefficients calculated from regression analysis and valid for the standards on hand only; the theoretical binary coefficients that are essentially constant in a given concentration range; then the theoretical multi-element coefficients calculated from one given composition and valid for one specimen only.With theoretical coefficients, however, a special calibration process is needed, because theory cannot take into account all the instrumental parameters. In the proposed calibration method it will be shown that the slope of the calibration curves is the link to correlate the theoretical formalism to the experimental reality; that the standards used do not have to be similar to the unknowns and that a few only are required; that the calibration curves can be extrapolated by a factor of two or three; that pure analytes are not required.
How to Use the Features of Total Reflection of X-Rays for Energy Dispersive XRF
Authors: Schwenke H. , Berneike W. , Knoth J. , Weisbrod U. 
Published: March 2019

AbstractThe total reflection of X-rays is mainly determined by three parameters , that is the orltical angle, the reflectivity and the penetration depth. For X-ray fluorescence analysis the respective characteristic features can be exploited in two rather different fields of application. In the analysis of trace elements in samples placed as thin films on optical flats, detection limits as low as 2 pg or 0.05 ppb, respectively, have been obtained. In addition, a penetration depth in the nanometer regime renders Total Reflection XRF an inherently sensitive method for the elemental analysis of surfaces. This paper outlines the main physical and constructional parameters for instrumental design and quantitation in both branches of TXRF.
Quantitative Analysis of Fluorine and Oxygen by X-ray Fluorescence Spectrometry Using a Layered Structure Analyzer
Authors: Takemura Momoko , Ohmori Hirobumi 
Published: March 2019

Recently, layered structure analyzers (called LSA for short) or layered synthetic microstructures (called LSM) with d spacing of several tens of Å, have been developed for use as X-ray analyzing devices in wave-length dispersive spectrometers. The lower detection limit for light elements of atomic numbers lower than 13 , such as aluminum, sodium, fluorine, oxygen, carbon and so on, has been greatly improved.There have been several reports published regarding LSA (or LSM) applications to light element analyses.
Modern Alloy Analysis and Identification with a Portable X-ray Analyzer
Authors: Piorek Stanislaw 
Published: March 2019

AbstractThe combination of an improved resolution, gas proportional detector with advanced microprocessor technology provides a new and unique solution to the problem of alloy analysis.A field portable, microprocessor controlled, fully user-programmable x-ray analyser is described for fast, reliable, on-site, positive alloy identification and assay. The radio-isotope based analyser employs a modified Lueas-Tooth and Price model of intensity corrections for quantitative, multielement analysis. Applications are reviewed and include examples to show the superior performance of the instrument in such difficult eases as sulfur in carbon steels, and titanium and nickel in stainless steels.Discussion of the unique alloy identification scheme and its underlying principles is followed by examples of applications illustrating the capabilities of the instrument in distinguishing, in 5 seconds, alloys of closely similar compositions such as stainless steels 303, 304 and 321, and 410 and 416.
Density Measurement of Thin Sputtered Carbon Films
Authors: Gorman G. L. , Chen M.-M. , Castillo G. , Perera R. C. C. 
Published: March 2019

AbstractThe densities of sputtered thin carbon films have been determined using a novel X-ray technique. This nondestructive method involves the measurement of the transmitivity of a characteristic soft (low energy) X-ray line through the carbon film, and using the established equation I1 = I0eμpt where I1/I0 is the transmitivity, fi the photo absorption cross section, t the independently measured thickness, the density p can be easily solved for. This paper demonstrates the feasibility of using this simple technique to measure densities of carbon films as thin as 300 Å, which is of tremendous practical interest as carbon films on this order of thickness are used extensively as abrasive and corrosive barriers (overcoats) for metallic recording media disks. The dependence of the density upon film thickness for a fixed processing condition is presented, as also its dependence (for a fixed thickness) upon different processing parameters (e.g., sputtering gas pressure and target power). The trends noted in this study indicate that the sputtering gas pressure plays the most important role, changing the film density from 2.4gm/cm3 at 1 mTorr to 1.5gm/cm3 at 30 mTorr for 1000 Å thick films.
Determination of Ultra-Thin Carbon Coating Thickness by X-ray Fluorescence Technique
Authors: White R. L. , Huang T. C. 
Published: March 2019

AbstractA tcchniquc for high-precision measurement of carbon thin-film thickness using X-ray fluorescence (XRF) is described. A quadratic calibration procedure is used for carbon thin films on silicon. Measurement of carbon-film thickness in a double-layer structure of carbon and CoCrX alloy is complicated by interference effects from the underlying layer. The dependence of the relative precision in measuring thickness (σT/T) on the counting time has been derived. It shows that a precision of 2% for a 25-nm carbon coating can be obtained using a W/C crystal and counting time of 4 minutes. Intensity and resolution advantages provided by the recently developed Ni/C and V/C multilayer synthetic crystals are also described.
Effect of Plastic Deformation on Oscillations in "d" vs. sin2ψ Plots a FEM Analysis
Authors: Noyan I. C. , Nguyen L. T. 
Published: March 2019

AbstractOscillations jn "d" vs. sin2ψ plots are due to the inhomogeneous partitioning of strains within the diffracting volume. In polycrystalline specimens, such inhomogeneity can be caused by the elastic incompatibility of neighboring grains or by the inhoniogeneous partitioning of plastic deformation within the diffracting volume. There is, however, little work on the degree of inhomogeneity required to cause a given oscillation, and the relative contribution from the elastic and plastic deformation components to a given oscillation.
X-ray Measurement of Grinding Residual Stress in Alumina Ceramics
Authors: Yoshida Hiroyuki , Hanayama Yukio , Morimoto Yoshitaka , Hirose Yukio , Tanaka Keisuke 
Published: March 2019

Machine parts made of ceramics are usually finished by grinding. Residual stresses as well as defects introduced by grinding will influence the fracture strength and the function of ceramics parts. Although several investigations used the X-ray diffraction method to measure the grinding residual stresses, their grinding conditions were rather limited.In the present study, sintered alumina ceramics of 99% purity were ground with a resinoid diamond wheel (#140 grain size number) under various grinding conditions. The effects of depth of cut and stock removal on the residual stress was measured with the X-ray method.
Specific Data Handling Techniques and New Enhancements in a Search/Match Program
Authors: Caussin P. , Nusinovici J. , Beard D. W. 
Published: March 2019

AbstractA Search/Match program using digitized X-ray powder diffraction Scans as inputs was presented in 1987 at the Denver Conference. This program has been rewritten to take full advantage of ttie newest capabilities of high end personal Computers. Software improveraents combined with the faster processing speed make it possible to search the 53,791 pattern data base in less than 16 seoonds typically (Compaq Deskpro 386/30 with 9 MB of RAM and 80387-20 numerioal processor), This can be compared to the 90 seconds one year ago. A specific program allows the user to create and, if desired, customize the searoh data base directly from the CD-ROM PDF-2, making Updates much easier. Praotiaal examples are given to illustrate the Operation of the proprietary pattern-recognition algorithm used in the search program.
LM-ACT for Imaging RAM Devices in X-ray Diffraction Topographs
Authors: Beard Warren T. , Armstrong Ronald W. 
Published: March 2019

Analysis of serai conductor material and associated integrated circuits (IC) is imperative for ensuring quality products. Currently, routine circuit testing is dominated by measurement of the optical and electrical material/device properties through final device performance and parametric testing.Characterization of the crystal microstructure still is not considered a routine process test. Structural characterization usually is based on double-crystal rocking curves, x-ray topography, or a combination of these techniques.
XRF in North America
Authors: Leyden Donald E. 
Published: March 2019

AbstractX-ray fluorescence, or X-ray spectrometry, is a dynamic analytical method; it undergoes constant change and improvement. Because of the early successes for the analysis of difficult samples such as metals, minerals and other solid materials, the technique was widely accepted in industrial applications. This occurred prior to the onset of large government funding to develop instrumental methods such as was provided for the development of inductively coupled plasma emission spectrometry. As a result, many of the important developments in XRF in North America have resulted from research and development by the instrumentation vendors and developments from Industrial and mission oriented government laboratories. There are exceptions, of course.
X-Ray Microanalysis for Alloy Design
Authors: Ohno Katsumi , Yamazaki Michio 
Published: March 2019

The characterization of alloys is strongly requested from metallurgists as basic data for computer aided alloy design systems for duplex type alloys such as α-γ type stainless steels, γ-γ’ type Ni-base superalloys, α-β type Ti alloys, etc. The characterization falls into the following three categories.
1)Determination of entire average composition of bulk specimens.2)Identification and the determination of phases including deleterious phases in the alloys.3)Determination of the composition of all phases in the alloys and the accuracy of the evaluation of the results obtained without standards.
High Spatial Resolution in X-Ray Fluorescence
Authors: Zahrt John D. 
Published: March 2019

During the past eight years or so there has been growing interest in using a polarized x-ray source in energy dispersive x-ray fluorescence spectrometers (1,2,3,4). The effect is to annihilate the source x rays before they scatter into the detector, thus significantly increasing the signal to noise ratio.Both characteristic or Bremsstrahlung radiation can be polarized by 90° scattering from crystals (Bragg angle = 45°) or from amorphous materials respectively. This 90° polarizing scatter event greatly reduces the incident source radiation on a sample. In an effort to regain some intensity use is made of concave surfaces to utilize a manifold of beams (5,6,7).
Layered Synthetic Microstructures in Sequential and Simultaneous X-Ray Spectrometry
Authors: van Eenbergen Ad , Volbert Bernd 
Published: March 2019

SummaryFor many years Layered Synthetic Microstructures (LSM's) have been used successfully as dispersive devices. The commercial variety introduced in 1984 offered significantly greater stability and diffracted intensity characteristics over Thallium Acid Phthalate (TAP) crystals. These devices offer superior sensitivity for fluorine, sodium and magnesium in all but a few applications where resolution is very critical. Subsequently, a variety of these devices have been optimised for analysis of the lower atomic number elements.Recently, several industrial applications have required the development of LSM's with 2d spacings optimised to enable quantitative analysis of oxygen, nitrogen, carbon and even boron. In these applications, the large incremental difference in characteristic wavelength per atomic number step limits the dynamic range of elements over which the LSM can be optimised. These considerations are discussed as they relate to routine analyses of very low atomic number elements by sequential Wavelength Dispersive Spectrometry (WDS).Newly developed fabrication techniques are used to produce curved LSM's for use with the focusing optics of simultaneous WDS. Application of these curved devices for the analysis of Mg in steel, Na in slags and F in glass will be discussed.Finally, an application which requires the analysis of thin films on semiconductor devices will be described. In this method, characteristic K-spectra and L-spectra of low and high atomic number elements, respectively, are selected for optimum sensitivity to the surface composition.
X-Ray Fluorescence Analysis of Sulphur and Trace Elements in Coal and Oil Tar Pitches, Asphalts and Other Bituminous Compounds
Authors: Kocman Vladimir 
Published: March 2019

AbstractA novel windowless sample preparation method is described which allows for X-ray fluorescence analysis of light elements (Z = 13 to 20) in coal or oil-tar pitches, asphalts and other bituminous compounds. The article also discusses blending and spiking of pitches with suitable organometallic compounds in order to prepare a range of trace-element calibration standards. The general instrumental conditions, recommended peak counting times and detection limits are also discussed.
Multielement Preconcentration of Rare Earth Elements for Their Determination at ppm-Levels in Geological Samples
Authors: Wolf Eva , Wegscheider Wolfhard , Kolmer Hans 
Published: March 2019

AbstractA preconcentration procedure is reported for rare earth elements suitable for concentration levels generally found in rocks. This method is of geochemical interest because the abundance of rare earth elements gives important clues to the origin of rock formations.The procedure is based on an anion-exchange separation step followed by a precipitation of rare-earth elements chelates onto a membrane filter. For the investigation of recovery a combined radionuclide tracer and X-ray sensitivity method was used. Detection limits in the sub-μg/g-range are reported.
Lattice Parameter Determination Using Synchrotron Powder Data
Authors: Parrish W. , Hart M. , Huang T. C , Bellotto M. 
Published: March 2019

AbstractA method for using synchrotron-radiation parallel-beam X-ray diffractometry for precision measurement of scattering angles and lattice parameters is described. The important advantages of the method are the high P/B made possible by wavelength selection and high source intensity, the symmetrical profiles and the absence of most systematic errors making it unnecessary to use standards. Profile fitting with a pseudo-Voigt function is used to determine 2θ to 0.0001º. The zero-angle correction and lattice parameter were determined from least-squares refinement and the average accuracy of observed-calculated 2θs was 0.0020°. Average values of ∆d/d = ∆a/a directly calculated from the individual hkl measurements ranged from 2x 10-5 to 5.7 x 10-5. The precision estimated from the standard deviation of the mean is in the 10-6 range and 1 ppm precision was obtained for Si. The determination of the exact wavelength selected remains to be solved, but ratios of lattice spacings to standards such as NBS SRM 640a can be determined.