bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oriented Crystallization of Amides on Collagen with Modification of the Collagen Lattice
Authors: Shaw E. H. 
Published: March 2019

AbstractRat tail tendons were fixed in 4% formaldehyde at 250 g tension, soaked in nearly saturated solution of the amides involved, and dried while still under tension. X-ray diffraction patterns, taken with rotation around the collagen fiber axis, showed well-defined layer lines of the amide and usually substantial expansion of the collagen equatorial spacing.The layer lines on collagen, in two cases on abnormal or polymorphic axes, are clustered around the number 4.86 ± 0.33 Å, or a figure twice this, implying the presence of a repeating hydro gen-bond accepting group such as the carbonyl group at this interval. The prominent collagen layer line at 9.4 Å is approximately double this interval.
A Vertically Rotating Double-Crystal X-Ray Spectrometer
Authors: Wittels M. C. , Sherrill F. A. , Kimbrough A. C. 
Published: March 2019

AbstractA versatile double-crystal X-ray spectrometer has been developed for the precise measurement of X-ray diffraction line widths to tenths of seconds. The device can be employed in either the parallel or antiparallel arrangement for rocking curve studies and can also be used in anomalous X-ray transmission experiments with nearly perfect crystals.A detailed description of the instrument is given as well as some results concerning the Darwin theory of X-ray diffraction line widths and Borrmann effects.
Beam Stability in the Electron Probe Microanalyzer
Authors: Fitzgerald Ray 
Published: March 2019

AbstractThe reliability and speed at which an analysis can be completed, using methods of the electron probe microanalyzer, depends to a large extent on the stability of the electron beam. The incident electron energy and total incident current must be maintained within prescribed limits to ensure accurate and reproducible X-ray data. The incident electron probe diameter must also stay within prescribed limits for maximum resolution over the analysis time. The performance of the electron optics is discussed in relation to high-voltage supply, current regulators, and filament supply. Methods for probe current stabilization using aperture sensing are discussed.
Double-Scanning Diffractometry in the Back-Reflection Region
Authors: King Hubert W. , Russell Carolyn M. 
Published: March 2019

AbstractA scanning range over Bragg angles from −163 to +163° 2θ is obtained by combining a diffractometer capable of scanning both sides of the primary X-ray beam with a very short (3-in.) high-power focused X-ray tube. The ability to scan the included angle 4θ between respective diffraction profiles on either side of the primary beam over the entire range of Bragg angles, provides a direct method of eliminating errors caused by a displacement of the specimen surface from the axis of the goniometer. The method is demonstrated by determining the lattice parameters of standard specimens used in the I.U.Cr. Precision Lattice Parameter Project.
Determination of Lattice Constants of Polycrystalline (Monoclinic) Uranium Tetrafluoride*
Authors: Morris Peter R. , Morton Vernon 
Published: March 2019

AbstractA technique is described for determining lattice constants of polycrystalline monoclinic materials and partition of observed experimental error among the several constants. The technique is illustrated for uranium tetrafluoride. Precision of the method is typically ±0.01 to ±0.02 Å on the unit cell lengths, and ±4 to ±8 min on the angle between axes. This is of the order expected, were single-crystal techniques limited to the range of Bragg angles available.
X-Ray Diffractometry of Polymers by a Transmission Method
Authors: Wilchinsky Zigmond W. 
Published: March 2019

AbstractThe practicability of using a symmetrical transmission method for accurate measurement of line positions and intensities for polymer samples was investigated. In comparison with the conventional symmetrical reflection method, the transmission method has some inherent advantages in the measurement of line positions. Very little extraneous line asymmetry is introduced by transmission, and errors due to sample misalignment can usually be corrected empirically. On the other hand, the reflection method introduces noticeable line asymmetry and a shift of the center of intensity toward smaller 2θ. Also, errors due to sample misalignment may be difficult to correct. Intensity measurements can usually be made with about the same accuracy by either method. However, the transmission method is less sensitive to misalignment errors, especially at the lower diffraction angles.
An Automated System for Extended X-Ray Absorption Measurements
Authors: Christofferson G. D. , Hughes T. R. , Klaver R. F. 
Published: March 2019

AbstractIn the study of X-ray absorption fine structure, one is faced with the task of measuring sample absorbance over an extended wavelength region. For the sake of accuracy, these measurements are often carried out on a fixed-count basis. Manual collection of the data at a hundred or more spectrometer settings is a tedious and time-consuming chore. This paper describes an automated system for accumulating absorption data.The equipment is used in conjunction with a Philips wide-range goniometer employed as a single-crystal spectrometer. It consists of: (1) a four-position sample changer, (2) a fixed-count selector for each sample position, (3) a five-digit counter and paper tape printer which register and record sample identification and counting times based on a 60-cps clock frequency, and (4) a programmer. The spectrometer advance is accomplished using the Philips step-scan arrangement. An IBM 7094 FORTRAN program for data reduction and computation will be described. The possibility of using X-ray absorption fine-structure measurements as a quantitative method for determining the various absorbing species will be discussed.
Light Element Analysis with an Electron Microprobe
Authors: Ong Poen Sing 
Published: March 2019

AbstractIn the microprobe, lead stearate decanoate multilayer analyzers have proven to be practical components for X-ray spectrochemical analysis of the light elements. Better controlled techniques in the deposition of the layers have already produced analyzers yielding improved peak to background ratios as well as higher counting rates. Operational techniques, optimizing instrumental performance, will be discussed. Analytical data on the elements fluorine through boron, obtained with a modified commercial microprobe, will be presented.
Variation of X-Ray Spectral Line Position with Ambient-Temperature Change: A Source of Error in X-Ray Spectrography
Authors: Lee Frederick S. , Campbell William J. 
Published: March 2019

AbstractThe effect of temperature change on LiF, ADP, and EDDT analyzing crystals was studied by measuring the change In intensity of a selected X-ray spectral line while maintaining a constant 2θ position on the spectrometer. A change in interplanar spacing due to thermal expansion and contraction satisfactorily account for experimentally observed line shifts for LiF and ADP. EDDT showed a large unexplained decrease in reflectivity with increasing ambient temperature.An equation was developed to express the change in intensity at a constant 2θ position as an exponential function of temperature. In this equation the thermal expansion coefficients of the principal axes of the crystal, the width of the spectral line at half-height, and the Bragg angle appear as factors. Intensity changes due to peak shift were tabulated for LiF, ADP, NaCl, silicon, germanium, quartz, calcite, fiuorite, and topaz.
X-Ray Study of Wire-Drawn Niobium and Tantalum
Authors: Adler R. P. I. , Otte H. M. 
Published: March 2019

AbstractDeformation, introduced into niobium and tantalum specimens by wire drawing at room temperature, produced changes in the shape and position of X-ray diffraction peaks. The resultant peak profiles and locations of all available peaks were recorded using the Debye-Scherrer geometry on a modified dtffractometer with crystal monochromated Cu Kα radiation. The amount of deformation in the surface layers of both metals was found to saturate essentially after only 20% reduction in area. The measured decrease in the lattice parameters of either material was attributed to a residual surface stress; the average value for the deformed saturated state for both tantalum and niobium wires corresponded to an equivalent longitudinal tensile stress of 35 ± 5 kg/mm2. Integral breadth measurements revealed approximately equal X-ray particle sizes in the <100> and <110> directions; the minimum particle size for the micro structures of both metals was around 200 Å and occurred after the first few draws.
Oriented Crystallization of Urea in Membranes
Authors: Shaw Edwin H. 
Published: March 2019

AbstractInner egg shell membrane was soaked in 2 M urea solution and dried. CuKαX-rays directed perpendular to the membrane yielded an urtsymmetrical diffraction pattern with urea 110, 111, 102, 210 and 211 planes diffracting to the right and urea 101, 200 and 201 planes diffracting to the left. The urea appears to be hydrogenbonded diagonally between the lamellae of β-keratin at an angle of 33.5° to the 6.68 Å b-axis (fiber axis) of the parallel pleated sheet structure, shortening the half-axis lengths in the a direction from 4.73 Å to 4.41 Å. Similar results were obtained with formalinized dog mesentery. Keratinous outer egg shell membrane, formal in bed collagenous dog renal capsule, formslinized collagenous pheasant pericardium, and formalinized callogenous human arachnoid yielded symmetrically oriented urea layer lines. Formalinized dog renal fascia and pleura yielded random urea lines.
Plane-Polarized, Two-Crystal X-Ray Spectrometer
Authors: Donahue Raymond J. , Azároff Leonid V. 
Published: March 2019

AbstractA two-crystal spectrometer employing a Cole polarizer made from a germanium crystal as one of the crystals is described. Experimental tests show that placing the polarizer crystal in the second position markedly improves the degree of plane polarisation, in full agreement with the predictions of the dynamical theory of X-ray diffraction. Tests indicate that the twice-diffracted beam h better than 95% plane polarized. The angular resolving power of the instrument is comparable to that of conventional two-crystal spectrometers. The almost wholly planepolarized monochromatic X-radiation, moreover, permits certain tests to be carried out far more effectively than is possible with partly polarized X-ray beams.
The Application of the Ziebold Correction Procedure for Probe Data to Three Ternary Copper-Base Alloys
Authors: Ingersoll Richard M. , Taylor Jack E. , Derouin Donald H. 
Published: March 2019

AbstractFor the quantitative analysis of a 65 Cu-30 Ni-S Fe alloy, a 96 Cu-3 Si-1 Mn alloy, and a 78 Cu-20 Zn-2 Al alloy, the Ziebold empirical method of correcting electron-microbeam-probe data was used. Four binary standards, of single-phase Cu-Ni, Ni-Fe, Cu-Mn, and Cu-Zn alloys, were cast and the a correction factor found for each element in each binary by Ziebold's relationship (1 – K)/K – α (1 – C)/C, where K – I/I0 found in the probe and C is the weight fraction found by wet chemistry. The ARL EMX probe was used at 30 kV with a 25-μ beam diameter to negate inhomogeneities. Experience with these binaries indicated that in the presence of secondary fluorescence, the experimental α values agreed poorly with theoretically calculated K values; however, where secondary fluorescence was negligible, agreement between the experimental and theoretical α values was good. The α values for Cu–Si, Cu–Al, Al-Zn, and Mn–Si alioys, were therefore calculated from the theoretical equations. The α values for Cu–Fe alloys were also calculated from theoretical considerations because single-phase binaries over the composition range of interest could not be made for this system. All these α values were used in Ziebold's ternary equations to correct probe data (again using a 25-μ beam) from specimens of Cu–Ni-Fe, Cu–Si–Mn, and Cu-Zn–Al. These results were compared to wet-chemistry analyses for the same specimens with quite good correlation between the two sets of data. Calibration curves for the binary systems Cu-Ni, Cu-Fe, Ni-Fe, Cu-Mn, Cu-Si, Mn-Si, Cu-Al, Cu-Zn, and Al-Zn were made and are reproduced.
L and M X-Ray Spectra in the Region 2-85 Å
Authors: Davidson Franklin D. , Wyckoff Ralph W. G. 
Published: March 2019

AbstractA detailed study has been made of the intensities of the L, M, and N X-ray spectra for wavelengths in the region from 2-85 Å. Some of the lines of these spectra involve energy levels which are gradually being depopulated with decrease in atomic number, and this leads to a progressive simplification of the spectra as the wavelength increases. Spectra have also been obtained from several compounds involving these elements in different valence states. Differences in relative intensities have been observed for these compounds, but because of a lack of accurate information about absorption, it is impossible as yet to give such results an adequate interpretation.
Application of Multilayer Analyzers to 15-150 Å Fluorescence Spectroscopy for Chemical and Valence Band Analysis
Authors: Henke Burton L. 
Published: March 2019

AbstractMethods and instruments have been developed for efficient spectroscopic analysis in the 15 to 150 Å ultrasoft X-ray legion using specially designed Langmuir-Blodgett type multilayer analyzers with a flow proportional counter detection system. Simple adaptations of the basic Philips vacuum spectrograph are employed with a high-intensity, demountable, ultrasoft X-ray source to excite fluorescence in the lighter elements for chemical and valence band analysis.
Some New Methods of Precision X-Ray Spectrometry
Authors: Das Gupta K. , Welch Herbert , Gott P.F. , Priest John F. , Cheng Sunny , Chu Edmond 
Published: March 2019

AbstractThree novel methods of x-ray spectrometry have been developed in recent years at Texas Tech University. These are:1. Three crystal spectrometer2. Two curved crystal spectrometer3. Spherically bent crystal spectrometer.In this paper the new design features, and experimental results will be discussed to indicate the usefulness of the new instruments. The three crystal spectrometer is a modified two crystal instrument. A third crystal is used to analyze the output of the two crystal spectrometer. The first two crystals are operated as a standard two crystal spectrometer. The third crystal is swept through the spectrum transmitted by the first two crystals for each setting of the first two crystals. The peak intensity of the third crystal sweep corresponds to the energy setting of the two crystal spectrometer, and is the intensity used to plot the spectral lines. The two curved crystal spectrometer utilizes two transmission spectrographs with radii having a 2:1 ratio in series, the crystal with the smaller radius being set so that its focal point falls on the Rowland circle of the larger radius crystal, This instrument has a very low background intensity and is suitable for precision scattering and diffraetion work. The spherically bent crystal spectrometer makes use of high light gathering power and high orders of reflection to allow high resolution studies of weak spectral lines. It also has the advantage of ease of alignment and operation.
The Effect Of Self-Irradiation on the Lattice of 238(80%)PuO2. II
Authors: Roof R. B. 
Published: March 2019

AbstractThe results of the third year of observations on the effects of self-irradiation on the lattice of 238(80%)PuO2 indicate a small but definite trend toward a reduction in the lattice parameter of this material. The lattice parameter increased from 5.41408±6 Å at 5 weeks to 5.41636±38 at 114 weeks and then decreased to 5.41364±23 at 157 weeks after the start of the experiment. A similar trend is noted in the half-widths of the diffraction lines. For the 622 reflection the half-width increased from 0.283±14°20 at 5 weeks to 0.711±90 at 114 weeks and then decreased to 0.660±89 at 157 weeks.
Measuring Techniques of Parallel Beam-Diffraction Micrography
Authors: Barth H. 
Published: March 2019

AbstractExamination of the substructure of crystalline solids by diffractographic methods has recently developed into an independent field of work alongside atomicstructure analysis. Diffraction micrography with electrons is characterized by the small size of the distortion fields and the high resolving power in small crystal ranges (1000-3000Å thickness). X-ray diffraction micrography is characterized by great reciprocation between wave field and distortion field and by undisturbed preparation and undisturbed testing in the large crystal ranges (up to 15 cm2). There are two groups of examination methods for diffraction micrography with X-rays: (1) Examination with a finely limited, polychromatic or monochromatic X-ray source and moving sample, according to A. R. Lang et al. (2) Examination with a parallel-ray beam of polychromatic or monochromatic X-rays with fixed sample, in accordance with Berg-Barrett et al. For the examination of coarse defects in single-crystalline and poly crystalline matter, the parallel-beam method offers a wide scope for studies in the physics and applications of single-crystal line and polycrystalline solids. This paper therefore includes a summary of the methods using collimation systems and grating diaphragms. Measuring techniques and results are illustrated with the help of reflection and transmission pictures on various crystals. The various methods and refined measuring technique of the parallel-beam method enable the following to be defined: (1) Localization of crystallites from 20 μ diam. upward in a surface up to 15 cm2. (2) Determination of the faces of averted crystallites from 20 µ diam. upward in crystal surfaces. (3) Angle of avertence of crystallites or curvature angles of net faces from 1 to 3° in crystal surfaces up to 15 cm2. (4) Subangle grain boundaries, slip bands, and dislocation lines; also distortion fields (from 20 μ upward) resulting from mechanical, thermal, and radiation damage.
X-Ray Diffraction Microscopy of Planar Diffused Junction Structures
Authors: Howard J. K. , Schwuttke G. H. 
Published: March 2019

AbstractBasic processing steps utilized in the fabrication of planar silicon devices include (a) substrate preparation, (b) epitaxial deposition, (c) thermal gvowth of silicon dioxide over the entire silicon wafer surface, (d) device pattern formation by photoetching techniques, and (e) diffusion of n-type or p-type elements through the holes to produce localized regions of desired conductivity, A detailed study of the various diffraction phenomena associated with such structures is presented. X-ray topographs of planar transistors show distinct contrast features such as excess diffraction intensity along the silicon oxide/silicon boundary and/or excess diffraction intensity inside the device area. The diffraction phenomena are discussed in terms of reversible elastic deformations, frozen-in lattice deformations, strain fields and imperfections generated by the various processing steps. A technique is presented to measure the sign of the elastic deformations. The phenomenon of stressjumping across semiconductors interfaces is described, and finally the implications of stress-strain relations on junction performance are stated.
Multilayer Soap Film Structures*
Authors: Ehlert R. C. , Mattson R. A. 
Published: March 2019

AbstractMultilayer soap film structures, particularly the lead stearate variety have been used for several years as a dispersing element in soft X-ray spectrometers. These structures have a high scattering power, and if a high order of diffraction is used for the shorter wavelengths they provide good resolution throughout the 10-80 Å range. Structures having a 2d spacing smaller than that of lead stearate (100 Å) would provide greater dispersion and, hence, resolution in the first order for radiation in the 10-40 Å range. Details concerning the conditions required to build multilayer structures from the soaps of shorter fatty acids such as lead myristate, lead laurate, lead caprate, etc. are given. The various members of the soap film family are compared regarding their diffracting power both as a function of wavelength and the order of diffraction. Information is given regarding the dependence of the diffracting power, the width of the diffraction peak at half maximum and the peak to background ratio as a function of the number of double layers in a structure. The absorption occurring within a lead stearate and a lead laurate structure has been experimentally measured. Observed spectra can, thus, be corrected for the filtration caused by the soap film structure. The soap film family is evaluated as a dispersing element by comparing the various Structures with single crystals such as EDDT and KAP.
Production Efficiencies of X-Ray Emission Spectra by Proton Bombardment
Authors: Sterk A. A. , Marks C. L. , Saylor W. P. 
Published: March 2019

AbstractProduction efficiencies for the excitation of characteristic soft X-ray emission spectra by proton bombardment were investigated. Results were obtained for K-, L-, and M-shell lines of various elements as a function of proton energies ranging up to 100 keV.For comparison putposes, helium, nitrogen, and argon ions also were accelerated and used as bombarding particles to yield efficiency data for some of the same spectral lines.The data demonstrate that:1.The production efficiencies of spectral lines excited by protons are, in the first approximation, dependent on wavelength only and are independent of the atomic shell with which they are associated.2.Production efficiencies increase with the atomic weight of the bombarding ions for some of the spectral lines investigated.X-ray generation by proton bombardment is a powerful method for producing high-intensity monochromatic radiation for wavelengths above approximately 10 Å, The same technique can be used for analytical purposes to determine the concentration of low atomic number elements.
Preparation of Electron Probe Microanalyzer Standards using a Rapid Quench Method
Authors: Goldstein J. I. , Majeske F. J. , Yakowitz H. 
Published: March 2019

AbstractStandards for microprobe analysis can be made to serve two purposes: (a) proposed correction models can be tested with them, and (b) analysis can be performed more accurately in the system which includes the standard. Few microprobe standards presently are available because they must be homogeneous on the micron scale and their composition must be known accurately. A modified Duwez splat cooling method is described which enables the investigator to prepare suitable standards in most cases. The apparatus which is relatively simple and inexpensive is described in detail. The systems Au-Si and Al-Mg were chosen as test cases. Suitable standards were prepared at different concentrations in each system. The analytical results for all compositions in Al-Mg are presented and discussed.
The Demountable Tube in Light Element Fluorescence Analysis
Authors: Short M. A. , Ruscoe M. J. H. 
Published: March 2019

AbstractIn view of the importance of obtaining optimum conditions for the X-ray fluorescence analysis of light elements, an investigation has been made of the effects of varying the X-ray tube target, the target take-off angle, the tube voltage, and the tube window thickness. The effects of these parameters have been observed by measurement of the intensity of fluorescence of two light elements using the Ray max 60 demountable tube and vacuum path spectrometer. The results obtained are compared with those given by theoretical calculations based on consideration of the relevant parameters; good qualitative agreement has been obtained. It is shown that a high primary X-ray intensity is obtained with a high target take-off angle, a low angle of incidence of the electron beam on the target, and an optimum setting of tube voltage. It is further shown that the most suitable target to use for the fluorescence analysis of light elements is markedly dependent on the thickness of the X-ray tube window.