bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glancing Angle X-ray Absorption Spectroscopy
Authors: Greaves G. N. 
Published: March 2019

AbstractThe use of glancing angles of incidence enables X-ray Absorption Spectroscopy to be measured as a function of depth from the surface of a material into the bulk. As x-rays rather than photoelectrons are detected, a UHV environment is not required and instead surfaces and interfaces can be examined under realistic operational conditions. Whilst the reflected beam carries the fine structure of concentrated species in the imaginary part of the refractive index, this is obscured by the contribution from the real part for angles greater than ϕc, the critical angle for total external reflection. Measuring the x-ray fluorescence offers more flexibility, particularly for dilute systems. The use of synchrotron radiation in conjunction with a multi-element Solid State Detector enables impurity loadings down to a few 1019 cm-3 to be measured which for ion implants is equivalent to around half-monolayer coverage at the surface. This sensitivity makes it practical to examine impurities in semiconductors at realistic dopant levels.
X-ray Fluorescence Analysis of High-Density Brines Using a Compton Scattering Ratio Technique
Authors: Samuelson Michael L. , McCormell Stanley B. 
Published: March 2019

AbstractHigh-density brines are used to control high pressure during oil and gas well operations. These dense brines (15 to 20 lb/gal) are solutions prepared from sale such as calcium chloride, calcium bromide, zinc bromide and/or combinations. During stages of completion, excessive losses of these expensive brines to the production zone can occur. Before the brine is reused in other oil and/or gas well operations, the brine may need to be reweighted. An analysis of the brine composition must be obtained to properly add the correct amount of salts.Standard addition or internal standardization methods are commonly used in X-ray fluorescence (XRF) applications but negate one of the advantages of XRF-elimination of tedious sample preparation. Scattered X-ray intensity has been used successfully to correct matrix effects in XRF applications. A Compton scatter ratio method is very advantageous for samples having a low atomic number, for which the scattered intensity is high. This paper describes an XRF method for determining Ca, CI, and Zn in high-density brines as well as the matrix correction for Br using a scattered X-ray ratio technique.
Mass Absorption Corrected X-ray Diffraction Analysis of Entrained-Flow Reactor Coal Combustion Products
Authors: Collins Leo W. , Wertz David L. 
Published: March 2019

AbstractThe analysis of coal and the understanding of the combustion process is complex, due to the heterogeneous nature of the material and the myriad of high-temperature reactions inherent in this fossil fuel. The research presented below utilizes recently-developed x-ray diffraction methods to analyze the coal combustion products generated from a laboratory-scale entrained-flow reactor. The reactor was designed, constructed, and tested, as planned for the initial phase of a long-term project to evaluate the coals located in Mississippi. In this initial phase a well-characterized coal was used, supplied by The Pennsylvania State University. The proximate, ultimate, and sulfur analyses of the coal, PSOC 1368p, are outlined in the Appendix. X-ray diffraction techniques have been used In the past to characterize coals. An analysis of the mineral transformation during coal combustion has also been performed using x-ray diffraction instrumentation. The semi-quantitative results of the pyrite (FeS2) phase transformation at variable temperatures and the percent combustion of the coal, as determined by x-ray methods are reported below.
The Thickness Measurements of Thin Bulk Film by X-ray Method
Authors: Hirose Y. , Takano N. , Nanayama Y. , Mura T. 
Published: March 2019

There are many investigations about thin film. However, these are limited to the surface layer thin film on substrates. It Is very important to know the characteristics of the extremely thin film itself such as surface layer thin film.In the present paper, the first part deals with the thickness measurements of the surface layer film and substrate by means of x-ray method, and then the measurement method of their stress - strain curves and the procedure of the measurement are described. The results obtained are discussed on the basis of their stress — strain curves.
Oxygen Concentration Determination in Silicon Single Crystals by Precision Lattice Parameter Measurement
Authors: Ohmori H. , Tomita M. , Tsuchiya N. , Matsushita Y. 
Published: March 2019

AbstractPrecision lattice parameter measurement by the X-ray diffraction method of Bond [1] has been examined as a substitutional method for IR in determining the oxygen concentration in silicon single crystals. Asymmetric 444 CuKai reflections were measured for undoped (100) oriented silicon wafers to obtain the correlation curve between the silicon lattice parameter and oxygen concentration. Precise adjustment of the optical system and computer fitting in determining the peak position allow a minute lattice dilation of silicon due to oxygen to be detected by the Bond method. The precision of this measurement system was of the order of 10-6. The lattice expansion of silicon by dissolved oxygen was determined to be at the rate of 3.2X10-24 atoms of oxygen per cm3. Furthermore, the oxygen concentrations of heavily Sb-doped silicon wafers were determined nondestructively.
An Expert System for the Validation and Interpretation of X-ray Residual Stress Data
Authors: Tricard Marc , Hendricks Robert W. , Guillot Marc 
Published: March 2019

AbstractAlthough widely recognized in the research community as one of the most accurate non-destructive methods for the determination of . residual stress in polycrystalline structural materials, x-ray diffraction has not been widely adopted in the field. This is partly due to the fact that such measurements require, most often, a well trained user with knowledge in both materials and mechanical sciences in addition to the specific know-how of the instrument. We believe that computer assistance could contribute to the promotion of this technique by increasing the productivity and accuracy of these measurements. We have developed a prototype expert system, using Nexpert Object's shell, to assist a non-trained operator in the validation and interpretation of X-ray diffraction residual stress data.The present work describes this prototype which has been designed to confirm the feasibility of the concept. Its knowledge base contains relevant examples of the rules necessary for data validation. The prototype has also confirmed most of the concepts required for the implementation of a full-scale version by evaluating all of the major technical features such as graphics representation, external routines and database access.
Use of X-ray Diffraction Using Gaussian Curve Method for Measuring Plastic Strain of Steels
Authors: Kurita Masanori , Chiaki Kenzo 
Published: March 2019

AbstractPlastic deformation of metals will broaden the x-ray diffraction line. The diffraction line around its peak can he approximated by a Gaussian function. The broadness of the diffraction line can be evaluated by the standard deviation, called Gaussian curve parameter (GCP), of a Gaussian function approximating the diffraction peak. Plastic strains applied to mild steels by simple and combined tension, compression, and tortion were correlated with GCP. Two kinds of GCP's were determined; the one, GCP α', was determined from the diffraction line corrected for the background counts, and the other, GCP α, was from the line uncorrected for the background, The GCP α' can be obtained from the GCP α asα' = 0.936α + 0.011This equation shows that the background subtraction can be omitted in determining GCP. The equivalent plastic strain ɛeq can be evaluated from the GCP a asɛeq - 0.000108 x 103.97αThis x-ray method allows rapid measurement of complex plastic strain without touching specimens.
Residual Stress Analysis of Silicon Nitride to Carbon Steel Joint
Authors: Kurita Masanori , Kano Takashi , Sato Takashi 
Published: March 2019

AbstractThe residual stress distribution of a ceramic-metal joint specimen was determined by both two- and three-dimensional thermoelastoplastic stress analyses using the finite element method (FEM). The residual stress on the surface of the specimen was also measured by x-ray diffraction. A specimen was prepared by brazing a silicon nitride plate to a carbon steel plate. The highest tensile stress σx perpendicular to the interface appeared at the corners of the silicon nitride adjacent to the interface. The maximum compressive stress σy parallel to the interface occurred at the center of the interface of the silicon nitride. The residual stresses in the silicon nitride and the steel plates distribute antisymmetrically with respect to the center of the specimen. Around the interface, the high stress concentration occurs and the residual stress distributes three-dimensionally, giving a wrong result by the two-dimensional FEM. The residual stress distribution measured by x-rays was similar to that calculated from the three-dimensional FEM.
New Methods for the Accurate Comparison of Lattice Parameters
Authors: Bowen D. K. , Tanner B. K. 
Published: March 2019

AbstractTwo new methods of comparison of lattice parameters are described. The first method uses a double crystal diffractometer, fitted with a specimen rotation stage. Bragg peak positions of a silicon reference and the specimen crystal are recorded for the crystals at 0 and rotated 180° about the diffraction vector. From the mean Bragg positions the lattice parameters can, in principle, be compared to parts in 106. The second method is a variant on the above, using a triple axis diffractometer. It uses a beam conditioner and monochromator to define the incident wavevector ko, and an analyser crystal to define the diffracted wave vector kh. Only the analyser motion must be accurate and stable to the arc second level. We present a detailed error analysis for the case where reference and specimen Bragg angles differ significantly. Peak location to a confidence level of 1 arc second permits absolute, traceable lattice parameter determination to several parts in 106.
High Speed Characterization of Pseudomorphic Hemt Structures Using a Very Low Noise Scintillation Detector
Authors: Loxley N. , Cockerton S. , Tanner B. K. 
Published: March 2019

AbstractWe show that a very low noise, high dynamic range scintillation detector has major advantages over conventional detectors for characterization of pseudomorphic HEMT structures by high resolution X-ray diffraction. We show that the reduced background enables a second modulation period to be detected, enabling the thickness and composition to be determined independently. Using a conventional X-ray generator and diffractometer we demonstrate that, in a single scan taking only 10 seconds, we are able to obtain sufficiently good data to provide quality assurance.
Combined Asymmetric Reflection and Transmission Method for High Accuracy X-Ray Crystallographic Measurements
Authors: Dragoi Danut 
Published: March 2019

AbstractThe work describes a method for determining the orientation of crystallographic planes in thin samples using both asymmetric Bragg reflection and asymmetric Laue transmission method.The method is based on the extension of a system of nonlinear equations for the reflection case. The solutions of the system of nonlinear equations in question can be positive, negative or mixed with physical significance. The positive solutions correspond to reflection case, while the negative solutions are for transmission case. The mixed solutions were generated for the planes {111} in a cubic structure.A theoretical test is given for a silicon sample. The results are in good agreement with the experimental results given in literature.
Residual Stress in Thin Films of Aluminum/Hafnium
Authors: Rant S. J. , Goldsmith C. C. , Noyan I. C. 
Published: March 2019

AbstractResidual stresses in thin films are important technologically due to their impact on the reliability of these structures. Various techniques are used to measure these stresses, and the results of these techniques do not always agree. In some cases, formation of interphase stresses were postulated to account for such discrepancy, but no definitive microstructural analysis was given. In this study, the residual stress response of evaporated films of 9 1% Al - 9% Hf (atomic %) deposited on 0.4 mm thick (100) Si wafers was studied as a function of thermal treatment. The stresses were measured by radius of curvature and d vs. sin2ψ techniques. Concurrently, the microstructure evolution was tracked using powder diffraction and metallographic techniques. As previously reported in the literature, residual stresses were tensile in all cases for both techniques. However, as expected, the stress results from both techniques did not always agree. The delta between the residual stresses measured by the radius of curvature and d vs. sin2ψ techniques were found to correlate well with the development of a 2nd phase (metastable cubic Al3Hf).
Small Area X-Ray Fluorescence Analysis of Multilayer Thin Metal Films
Authors: Zaitz M.A. 
Published: March 2019

AbstractThin film technology has become an integral part of semiconductor multichip ceramic packages. Characterizing the thickness of multimetal multilayer thin film structures that combine both thin and thick films is an important parameter for manufacturing process control and development. Accuracies in the range of 3-5% and precisions of 1.3% were attained on multilayer metal films ranging from a few hundred angstroms to tens of thousands of angstroms.
New Advantages in Soft X-Ray Stress Measurement and Triaxial Analysis of Nonuniform Stress States
Authors: Wem H. , Suominen L. 
Published: March 2019

AbstractConventional stress analysis with diffraction techniques is based on the equations of continuum mechanics, but only few materials encountered in X-ray stress analysis satisfy this assumption. In this paper, a new method is formulated yielding quantitative strain tensor fixed to the specimen coordinates. The method enables independent in-situ determination of Poisson's ratio which serves as a self control mechanism for measurement and evaluation. The analysis has been extended from flat to curved surfaces. Thus an exact analysts of spherical or cylindrical shaped specimens is now possible. The method has the capability to evaluate stress tensor and stress free lattice spacing at the surface as well as their variation with depth. This is demonstrated by two experimental data sets.
The Effective Thermal Expansion Of Nickel and Nickel Oxide During High-Temperature Oxidation*
Authors: Wolfi James S. , Cavin O. Burl 
Published: March 2019

AbstractX-ray diffraction analyses were applied to various pure nickel substrates while exposing them to oxygen at temperatures up to 800 °C. Coefficients of thermal expansion (CTE) were calculated from lattice parameters for both the nickel and the growing surface oxides. Behaviors more complex than the case for single phase bulk solids were observed due, in part, to oxidationinduced strains. The CTE values for such dynamic composite systems are not the same as those for the bulk solids. Thus, for example, the CTE values were found to be dependent on substrate metal thickness. In addition, discontinuities in the CTE's of both nickel and NiO occurred at or near their respective second order phase change temperatures.
The Construction Of Quantitative Inverse Pole Figures Using the Available Odf Data
Authors: Peng Charles , Ting Lu 
Published: March 2019

AbstractThe ODF calculation is, to a large extent, responsible for the increased interest in texture analysis. Accurate pole figures and ODF plots can be routinely obtained in the laboratory from x-ray units equipped with precision controlling devices. For studies of the plastic flow behavior of polycrystalline aggregates, it is important to present the texture results in a manner readily usable for these analyses. For samples having a simple concentrated texture, the presentation of the data in terms of conventional pole figures and ODF plots is usually adequate. Additional work however is frequently needed when the analysis is involved with a more complex texture. A method is described for constructing the quantitative inverse pole figure using the available ODF data. Attention is focused on the construction of inverse pole figures for FCC and BCC metals. Examples are given of the plastic flow analyses for copper and tantalum which were produced by different cold-forming processes to yield a multitude of texture elements. The modification and rearrangement of the computer program necessary to accomplish this task will be discussed.
Quantitative Analysis of 300 and 400 Series Stainless Steel by Energy Dispersive X-Ray Fluorescence
Authors: Wheeler Bradner D. , Jacobus Nancy 
Published: March 2019

Recent developments in analytical techniques and software have allowed the accurate quantitative determinations of both the major and minor elements in stainless steels by energy dispersive x-ray fluorescence. The successful analysis of 300 and 400 series stainless steel is reported utilizing this technique. The analysis of this type of material represents one of the most severe tests of the method due to numerous peak overlaps and interelement effects such as absorption and enhancement.Sixteen standards of ASTM 300 series and ten 400 series were prepared by polishing on a 220 grit aluminum oxide belt and subsequently washing the surface in absolute methanol. Analyses were performed with an EG&G ORTEC 6110 Tube Excited Fluorescence Analyzer utilizing a dual anode (Rh/W) x-ray tube. Peak deconvolutions and interelement corrections were made with a 16K PDP-11/05 computer utilizing the program FLINT (1). Utilization of spectral deconvolutions and interelement corrections yields a relative accuracy of approximately IX of the concentrations of the major elements.
Computer Techniques for Faster X-Ray Diffraction Phase Identification
Authors: Goehner Raymond P. , Garbauskas Mary F. 
Published: March 2019

AbstractThis paper describes the procedures used to retrieve JCPDS powder diffraction data by certain characteristics. These characteristics may include chemistry, mineral name, highest intensity dspacing, largest dspacing, PDF number, etc. The storage scheme used for the powder data and the procedures used to enhance the retrieval speed are described.
A Method of Background Subtraction for the Analysis of Broadened Profiles
Authors: Enzo S. , Parrish W. 
Published: March 2019

AbstractThis method for precisely determining the background level of broadened x-ray profiles assumes that the background under the peak can be approximated by a straight line, and the decay in the tails several profile widths from the peak follows a Cauchy-like law. It uses a plot of I(s)s2 vs. s2 where I(s) is the intensity and the scattering vector s = 2cosθo sin(θ-θo)/ƛ where θo is the centroid, θ the Bragg angle and X the x-ray wavelength. The true background is determined by the slope of the linear portion of the plot and its extension to s2=0 gives the rate of decay of the tails. Results on synthesized and experimental profiles show that the method is useful for Warran-Averbach analysis, because it avoids spurious oscillations and the “hook” effect in the plot of the corrected Fourier coefficients, and makes it possible to correct for overlapping tails of adjacent reflections.
Stress Evaluation on Materials Having Non-Linear Lattice Strain Distributions
Authors: Hauk Viktor M. 
Published: March 2019

AbstractThe state of the art of stress evaluation on materials having non-linear lattice strain distributions is presented.New results on heterogeneous materials with measurements conducted on both phases of the material show compensation of the shear stress components σ13 in ground surface layers of (α+β) brass. There is only the compensation of normal components σ11 of (α+γ) steel after plastic straining.The fundamental aspects and the evaluation of macro- and microresidual stresses on materials having preferred orientation are broadened. The use of Mo-Ka-radiation shows linear lattice strain distributions, as a result of minimizing the influence of micro residual stresses causing oscillations. The interplanar distance- or strain-polefigure shows similarities with the intensity polefigure.The knowledge of the theoretical influence of stress distribution with depth from the surface of the material is extended. The experimental procedure should use either different radiations having different penetration depths or a low-penetrating radiation in combination with removal of surface layers.
Determining Stresses in the Presence of Nonlinearities in Interplanar Spacing vs. Sin2ψ
Authors: Noyan I. C. , Cohen J. B. 
Published: March 2019

AbstractThe physical meaning of non-linearities in “d” vs. sin2ψ lines, encountered in X-ray measurements of surface residual stresses in polycrystalline materials is investigated. It is shown that when oscillations are present in any one reflection, switching to another reflection to obtain a straight line in “d“ vs. sin2.ψ is feasible only under very special conditions. We also discuss the effect of “quasi-homogeneous” strain distributions and investigate the effects of ψ-range on the accuracy of X-ray residual stress measurements when ψ-splitting” is present. A new geometric error is also discussed that can not be detected by the “annealed powder” method often used for alignment.
Direct X-Ray Measurement of Residual Strains in Textured Steel
Authors: Gazzara C. P. 
Published: March 2019

One of the most detrimental effects on the accuracy of an X-ray diffraction residual stress analysis, XRDRSA(l), is found in the examination of textured materials. The degree of elastic anisotropy and texture is in general agreement with the extent of the error in the residual stress. Several approaches have been made to correct for the effects of texture, particularly involving experimental techniques. Reviews of such efforts are given by H. D811e(2), v.M. Hauk﹛3) and G. Maeder, J.L. Lebrun and J.M. Sprauel (4), just to mention a few.A brief chronology of the texture corrections involved in XRDRSA follows. With isotropic materials the d spacing of a crystal lattice, d, is assumed to vary linearly with sin2ψ. With textured materials the d vs sin2ψ relationship is nonlinear. This is due to the anisotropy of the elastic constants and their departure from a random distribution, or taking on a preferred orientation.
Stress Determination in an Adhesive Bonded Joint by X-Ray Diffraction
Authors: Predecki Paul , Barrett Charles S. 
Published: March 2019

At the present time there is considerable interest in the use of adhesive bonded joints for structural applications. The design of such joints is based mostly on finite element calculations and failure tests rather than on strain or stress measurements. To our knowledge no measurements have been made of stresses at or near the adhesive/adherend interface (where many bond failures occur) because of difficulties with accessibility. The purpose of this work was therefore to try to make such measurements using X-ray diffraction.The approach taken was to gain access to the bond by making one of the adherends in a single lap joint to be relatively transparent to X-rays and the cither relatively opaque. Incident X-rays then penetrated the first adherend and the adhesive and were diffracted from gains in the second adherend adjacent to the adhesive/adherend interface. Stresses resulting from curing of the adhesive were determined first, after which a load was applied and the stresses redetermined.