bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Accurate Coefficient Method for X-Ray Fluorescence Analysis
Authors: Tertian E. 
Published: March 2019

Performing highly automated, computerized X-ray spectrometric analysis ‘without standards’ calls for accurate matrix correction programs which can be based, essentially, on either the ‘fundamental parameter’ method or improved influence coefficient procedures. The coefficient scheme discussed in this paper was devised to strictly comply with the theoretical relationships for X-ray fluorescence emission, thus connecting, in a way, both approaches. This result is achieved by accurately making allowance for the two complicating factors affecting fluorescent intensities i.e. : (1) the mobility of coefficients, and (2) the occurrence of fluorescence crossed effects. The corresponding algorithm, for practical use, writeswhere the (aij + bij ci) terms account for the individual influence coefficients and their variation, and ϵi refers to the overall crossed effect. The essential problem of calibration is then considered, with special emphasis being laid on : (a) experimental coefficient determination, and (b) experimental crossed effect evaluation. Current coefficient methods are briefly surveyed in relation to the present theory.Finally, the advantages of an experimental, accurate coefficient procedure over the fundamental parameter approach, from a practical standpoint, are emphasized.
Some Applications of a Computer-Controlled X-Ray Spectrometer in a Steel Research Laboratory
Authors: Harter W. T. 
Published: March 2019

The U. S. Steel Research x-ray spectrometric laboratory performs between 7,000 and 10,000 analytical determinations each month for alloying elements in all types of steels and raw -materials. The spectrometer is automatically controlled by a DEC PDP 8/1 minicomputer utilizing vari ations of software packages provided by Siemens Corporation. As many as 256 individual analytical measurements can be sequentially performed. The minimal interelemental effects encountered in low-alloy steel analyses are corrected in a separate program written in FOCAL language. Correction coefficients for the program were established by multiple linear regression analyses.Stainless and multialloy steels are analyzed with a two-part control and correction program. The control program controls all functions of the spectrometer automatically and stores parabolic calibration coefficients. Following a sequential determination of the alloying elements control is switched to a correction program written in FOCAL. The correction program prints a tabular listing of the elements determined, followed by a listing of the corrected concentrations of elements adjusted for interelemental effects. Orthogonal polynomial analyses were performed to determine σ values for all constituents determined.For analysis of raw materials, the samples are fused prior to analysis by use of a flux and heavy absorber technique that essentially eliminates interelement effects and permits linear calibrations up to 100 percent. Samples are ground and pelletized after fusion for better reproducibility. Single sets of calibration standards are used regardless of raw materials mineralogical history. Synthetic standards can be produced for ranges where no calibration standards exist.
Energy Dispersive X-Ray Fluorescence Spectrometry Using Pulsed X-Ray Excitation
Authors: Jaklevic J. M. , Landis D. A. , Goulding F. S. 
Published: March 2019

An energy dispersive X-ray fluorescence spectrometer using pulsed X-ray excitation has been developed for use in large-scale environmental analysis programs. A grid controlled X-ray tube is coupled with variable secondary fluorescence targets to analyze for a wide variety of elements with almost optimum sensitivity. The operation of the pulsed tube in a feedback loop with the semiconductor detector spectrometer results in a substantial increase in output counting rates without pile-up. The loop functions by turning off the excitation immediately upon detection of an event by the spectrometer. Pileup events are virtually eliminated and the X-ray tube's available anode power is better utilized.The electronic control of this feedback mode results in some unique features in the response of the system to varying sample mass. These features are discussed in detail. Experimental results for sensitivity and accuracy over the range of elements measured are presented. Early operating experience with the unit indicates increases of counting rates of a factor of five compared with similar conventional systems.
The Use of Proton-Excited X-Ray Emission to Study: 1) Electrodeposited TiB2 Coatings and 2) Gas-Turbine Blade Failures
Authors: Sartwell B. D. , Needham P. B. 
Published: March 2019

A method to quantitatively analyze the surface regions of metals, alloys, and coatings using proton-excited X-ray emission (PEX) has been utilized in two areas of metallurgy research. This paper describes application of the technique to (1) the development of erosion- and corrosion-resistant coatings, and (2) the study of structural failures in turbine alloys.The technology for the electrodeposition of erosion- and corrosionresistant TiB2 coatings from molten-salt electrolytes has been developed in order to provide protective coatings for valve components in coal gasification plants. Analyses by PEX and X-ray diffraction have played the key role in the determination of the optimum electrolysis parameters required to obtain adherent, erosion-resistant TiB2 coatings. From these studies, the erosion resistance of a TiB2 coating can be predicted on the basis of (1) the amount of Cr and Fe impurities codeposited during electrolysis and (2) the degree of orientation of the TiB2 crystal structure along the (110) or (100) planes.PEX was used for analytical studies of a Nimonic 105 alloy turbine blade and an A-286 alloy turbine wheel from a San Diego, California, power generating station gas turbine that suffered a catastrophic failure in November 1974. Analyses of the turbine blade in the region at which the rupture occurred showed alloy composition changes that included decreases of 80%, 78%, 52%, and 50% of Al, Ti, Cr, and Co, respectively, and an increase of 2500% in Fe. Alloy composition changes were also found at the failure interface of the turbine wheel; these included decreases of 43%, 21%, and 15% in Hi, Cr, and Ti, respectively, and increases of 248% and 714% in Si and Al, respectively.
Theory & Performance of Holographically-Formed Stigmatic X-Ray Gratings
Authors: Speer R. J. 
Published: March 2019

Holographically-formed X-ray reflection grating scan now be constructed with competitive groove efficiency to classically ruled types, down to a short wavelength diffracting limit of several angstroms.The gratings can be generated on any surface capable of intersecting the interference fringe pattern without shadowing. This fact alone brings several new X-ray optical design possibilities within reach, for example, by combining plane construction waves with steep aspheric substrates. The first order imaging theory of the grazing incidence mounting is discussed and compared to measured performance for aberration corrected stigmatic types.A new 5 meter spectrograph has also been constructed with applications in molecular chemistry, laser fusion
research and synchro tronspectroscopy. The unit is available with fully prefocussed holographic and classical
X-ray grating optics, and uses the precision miniature camera principle of fully interchangeable lenses, but applied, in this case to the entrance slit, grating and detector modules.
The Application of a Position-Sensitive X-Ray Detector to the Measurement of Residual Stresses
Authors: James M. R. , Cohen J. B. 
Published: March 2019

In recent years considerable success has been achieved in the development of detectors for the localization of ionizing radiation. One dimensional position sensitive detectors have a number of uses in nuclear physics and in biological studies utilizing small-angle scattering. Detectors are now capable of providing position information of high resolution with a high count rats capability and a simple readout system. We report here on the feasibility of employing a position sensitive proportional counter (PSPC) for the measurement of residual stresses with X-rays.Comparisons of the accuracy and time of data accumulation between a scintillation detector and a PSPC have been performed on stress relieved, shot peened steel specimens, and specimens deformed in tension.The ability of obtaining the entire profile at once is somewhat offset by the lower efficiency of the PSPC when compared to a scintillation detector, but this is counteracted by the fact that motion of the detector is eliminated with the PSPC, It will be shown that a PSPC system provides a speed of data accumulation currently not available in any other way, while still remaining a versatile and accurate method.
Indexing Powder Diffraction Patterns
Authors: McLachlan Dan , Chen Sylvia 
Published: March 2019

AbstractDespite the fact that the many researchers, who have worked on the problem of indexing powder diffraction patterns, have made several important advances in the field and have proven in theory at least that any pattern can eventually be indexed, the procedures are frequently so laborious as to drive the investigator to despair. Starting with the knowledge that convolution functions and particularly self-convolutions ﹛so well known to crystallographers as Patterson functions) have the power to find the distances between points in space, and knowing that reciprocal space is filled with repeating distances, the present authors have evolved a graphical system for carrying out the previously discovered procedures in an easy and rapid manner.
On the Determination of Preferred Orientation in Ferritic Steels
Authors: Slane John A. , Hultgren Frank 
Published: March 2019

AbstractA new approach to the analysis of preferred orientation in body centered cubic sheet materials is presented. The technique utilizes normalized extended inverse pole figures (2θ = 16 to 150°) taken in the plane normal, rolling, and transverse directions. Possible texture components are defined to be all unique sets of three mutually orthogonal crystallographic planes included in the diffraction pattern up to 150° 2θ for a total of 56 possible components. A computer program has been developed to calculate the contributions of various texture components relative to the three principal directions by two computer implemented algorithms, probability and successive decrementation. The two methods exhibit an apparent high correlation.The calculated results are compared to monochromated direct pole figures for a highly textured material. The agreement is excellent.
The Effect of Surface Oxide on the Changes in the FeLII/LIII Ratio with Accelerating Voltage
Authors: Holliday J. E. 
Published: March 2019

AbstractMeasurements have been made on the FeLII/LIII intensity ratio on oxide free iron surface produced by evaporating a 50 Å Ti film on iron. These results show that the reported increase in the FeLII/LIII ratio with decreasing accelerating voltages is due largely to surface oxide and not self absorption. Also, for the vacuum presently used by soft x-ray spectroscopists the oxide surface on metals contribute strongly to the soft x-ray spectra of the bulk material for accelerating voltages below 4 kV.
Chemical Bonding Effects in X-Ray Emission Spectra - A Molecular Orbital Model
Authors: Urch David S. 
Published: March 2019

AbstractMolecules or ions usually exist as discrete units, in crystals of chemical compounds. Intermolecular or interionic coValent interactions are slight so the bond structure of such, solids is very similar to the pattern of energy levels in each individual molecule or ion. Simple molecular orbital theory can therefore be used to generate a qualitative picture of the energy levels in a molecule or an ion; and this picture can then be used directly to interpret X-ray emission spectra. The application of molecular orbital theory, using group theory to simplify the calculations is described for a tetrahedral unit ML4. The origin of peak shifts and of low-energy satellite peaks are rationalised. A consideration of orbital amplitudes shows that the ‘cross-over' theory of O'Brien and Skinner cannot explain the observed intensities of low-energy satellite peaks. It is suggested that the use of the M. 0. model for the interpretation of X-ray emission spectra permits far greater analytical and structural use to be made of peak shift and satellite data. Ligands can be identified even when their own characteristic emissions are not detected (e.g. oxygen and fluorine). Relative peak intensities can be correlated with atomic orbital participation in bond formation. Such information is of great interest to chemists and can often be used to identify the bonding r61e of specific orbitals (e.g. the 3d orbitals of second row, main group, elements).
Systematic Errors in X-ray Diffractometer Stress Measurements Due to Specimen Geometry and Beam Divergence
Authors: Zantopulos Harry , Jatczak Chester F. 
Published: March 2019

AbstractA method is described for determining the magnitude and sense of systematic errors in x-ray diffractometer stress measurements produced by focusing aberrations during diffraction from imperfect specimen contours and wide horizontal beam divergences. Corrections for such systematic errors are presently not made. However, if the highest accuracy and/or absolute values of stress are desired, these must be either taken into account or minimized by control of beam geometry. Equations and computer data are presented to indicate the errors in 2θ and stress (σ) resulting from use of flat, various convex and concave curvatures for primary beam divergences of 1° to 3°, Stress errors are calculated for both the parafocus technique of beam focusing and the stationary or non-focusing method.The results show that convex and flat specimens always produce negative 2θ deviations from the condition of perfect focus and thus a net positive or tensile stress error. The magnitude of this error increases as the radius of the convex shape decreases and/or the ψangle and beam divergence is increased. Concave specimens with curvatures less than the radius of the concave shape required for perfect focus (see body of report) produce positive 2θ deviations and, therefore, negative or com-pressive stress errors.The stationary or non-focusing technique produced systematic errors which were 1/3 of those produced by focusing aberrations with the parafocus technique. Fortunately, in both cases the actual errors are not very large (less than ±7.5 ksi), even with divergent beams as large as 3° and convex radii as small as 125”.
Crystal Distortions Associated with Magnetic Ordering in the Antiferromagnetic Compound VF2
Authors: McCain W. S. , Albright D. L. , Boo W. O. J. 
Published: March 2019

AbstractLattice constants were measured as a function of temperature by single crystal diffracrometry in the temperature range which includes the Néel temperature of VF2(TN= 7°K). The lattice constants of VF2(D4h14=P42m n m) were measured from room temperature down to 4.2°K. In this range rhe tetragonal c-axis contracts 0.58% from 3.2359 Å (RT) to 3.2170 Å (4.2°K). On the other hand, the a-axes show a net expansion of 0.18% from 4.8023 Å (RT) to 4.8110 Å at 4.2°K. The temperature dependence of the lattice constants can be correlated with anisotropy of exchange forces. Vanadium Ions occupy the center and corner positions of the unit cell. Strong magnetic interactions are directed parallel to the c-axis >001< with considerably weaker interactions parallel to the body diagonals >111< The relative strengths of the two exchange integrals are J >001< = 50 J >111<. As a consequence the magnetic ordering is one-dîmensional along the c-axis and the associated distortions arise from the strong magnetic interactions along this axis.
Calculated Patterns in X-Ray Powder Diffraction Analysis
Authors: McCarthy Gregory J. , Martin Kyli J. , Holzer Jean M. , Grier Dean G. , Syvinski Wayne M. , Nodland Darred W. 
Published: March 2019

AbstractCalculated patterns play an essential role in X-ray powder diffraction analysis. This paper gives examples of their use in qualitative analysis for evaluating and supplementing reference patterns in the ICDD Powder Diffraction File (PDF), in quantitative analysis for calculating Reference Intensity Ratios (RIRs), in ceil parameter refinements for indexing of low-symmetry/large unit cell diffractograms, in powder pattern determination for validating intensities and recognizing preferred orientation, in new materials synthesis for verification of structure type and phase purity, and for modeling the effects of solid solution substitution.
Rietveld Analysis and Pair Wise Substitutional Alloys
Authors: Kaplan Wayne D. , Kimmel Giora 
Published: March 2019

AbstractRietveld Analysis on X-Ray powder diffraction data was used to build a comprehensive model of the structures in gallmm rich R-Ga systems (R is a rare earth between La and Gd). The ability to refine occupation factors as well as atomic positions allowed for the analysis of the e solid solution, its structural relation to the ordered ∊′ phase, and the unique role of the Ga-Ga pairs in these systems.
The Effects of Sampling Error on Detection Limits Determined for Quantitative X-Ray Diffraction
Authors: Raab Gregory A. , Dalheim Peggy 
Published: March 2019

AbstractThis paper investigates the contributions of sample preparation to the analytical lower limits of detection and errors for the quantitative X-ray diffraction analysis of a simple, binary system of quartz and calcite. This study further demonstrates the danger of using only statistical and instrumental contributions to detection limits and analytical errors.
Prediction of the Diffraction Order Dependence of the Integral Reflection Coefficient of Multilayer Structures using Atomic Force Microscope Measurements
Authors: Brown D.B. , Konnert J.H. , Gilfrich J.V. , D'Antonio P. , Freitag R.K. , Rosenstock H.B. , Burkhalter P.G. 
Published: March 2019

AbstractThe evaluation and understanding of the x-ray diffraction properties of multilayer structures is critical in predicting the degree of success in their utilization in x-ray optics applications. A key material parameter affecting the diffracting efficiency of multilayer structures is the roughness of the interfaces between the deposited layers. This paper will use measured roughness to predict the integral reflection coefficient as a function of diffraction order for several multilayer structures.We have made atomic force microscope (AFM) measurements of the detailed displacement distribution for me surface roughness of W/C and W/Si multilayer structures. This information has been introduced into a theoretical model to predict the reduction of the integral reflection coefficient induced by surface roughness. In a fashion analogous to the Debye-Waller factor, this reduction in diffracted intensity is predicted to be strongly dependent on the diffraction order. These predictions have been compared with experimental integral reflection coefficient data. The measured diffraction results indicate a greater reduction in reflection than is predicted by the AFM measurements. A possible explanation for this discrepancy is that the AFM measurements underestimate the roughness. Possible reasons for the differences between these methods will be discussed.
Synthesis Analysis of Thin Films by XRD and SEM
Authors: Fujinawa Go , Tobe Shogo 
Published: March 2019

AbstractThis is a report of an investigation by XRD and SEM of thin coatings such as are applied by plasma spray methods for improving properties, such as are wanted in electronic devices, and for increasing durability in service. Samples were studied that had been coated under controlled conditions: Physical Vapor Deposits (PVD) of titanium nitride on steel plate and plasma spray coatings of molybdenum on steel plate. X-Ray determinations were made of x-ray lattice constants, crystallite size, lattice strain, orientation and residual stress, before and after strain was applied to the specimens.
Investigation of Semiconductor Heterostructures by White Beam Synchrotron X-Ray Topography in Grazing Bragg-Laue and Conventional Bragg Geometries
Authors: Yao G.-D. , Wu J. , Fanning T. , Dudley M. 
Published: March 2019

AbstractWhite beam synchrotron X-ray topography has been applied both to the characterization of two semiconductor heterostructures, GaAs/Si and InxGa1-xAs/GaAs strained layers, and a substrate to be used for growing semiconductor epilayers, Cd1-xZnxTe. In the case of the heterostructures, misfit dislocations were observed using depth sensitive X-ray topographic imaging in grazing incidence Bragg-Laue geometries. The X-ray penetration depth, which can be varied from several hundreds of angstroms to hundreds of micrometers by rotating about the main reflection vector, which in this specific case was (355), is governed by kinernatical theory. This is justified by comparing dislocation contrast and visibility with the extent of the calculated effective misorientalion field in comparison to the effective X-ray penetration depth. For the case of Cd1-xZnxTe, twin configurations are observed, and their analysis is presented.
Construction of a Multimode High Resolution X-Ray Powder Diffractometer and its Perfomance
Authors: Kurahashi Masayasu , Honda Kazumasa , Goto Midori , Inari Yu , Katayama Chuji 
Published: March 2019

AbstractRecently some of the above authors determined the structure of an unsolved organic compound employing X-rays from a Synchrotron, an Imaging Plate, and a large radius camera. It would be more desirable if the high quality powder diffaction data could be obtained by a diffractometer or a camera of laboratory use. Therefore a multimode X-ray powder diffractometer which can be used for various experimental geometries such as Bragg-Brentano mode, Guinier mode and parallel beam mode was constructed in order to find the highest resolution geometry. In this paper wc present the results of the measurements employing these three modes.
Time-Resolved Observations of Solid Reactions and Structure Transitions using a PSD, An SSD and Computer Aided Measurement and Control
Authors: Yamanaka Takamitsu , Kawasaki Shinji , Shibata Tsuyoshi 
Published: March 2019

AbstractFor time-resolved diffraction studies under high temperature and/or high pressure, we designed a new diffractometer incorporating a curved position sensitive detector and tested the rapid intensity measurement and the resolution of the angular dispersive diffraction. The diffraction profiles were compared with those from energy dispersive diffraction. Rapid intensity collection has been carried out with a CAMAC module. A curved position sensitive detector with a 120° working angular region was installed on the off-centered four circle diffractometer. Only a few seconds were needed to obtain a whole powder diffraction because of the extremely high counting efficiency due to the streamer mode.Time-resolved observations of the dehydration reactions of Mg(OH)2 and Ca(OH)2, have been undertaken by angular dispersive and energy dispersive x-ray powder diffraction at high temperature. The in situ observations of the dehydration process provide kinetic information, such as the reaction rate, the apparent activation energy and the dehydration mechanism.
Young's Modulus Measurement of Chromium Electroplating
Authors: Ohtsuka Masaaki , Hatsuok Hideaki , Hirose Yukio , Ishii Hitoshi 
Published: March 2019

The electroplating of Cr has been an important industrial process for cutting tools, press machines and molds for casting. In spite of these, quite a few problems remain unsolved regarding the basic property. It is important to know the mechanical characteristics of Cr electroplated layers.In the present paper, the first part deals with the measurement of mechanical Young's modulus of Cr electroplated layers. The X-ray method was successfully applied to measure the X-ray Young's modulus and the residual stress on the Cr electroplated surface layer.