摘要:

A technique for the measurement of diffuse X‐ray scattering by a combination of an energy‐dispersive detector and a source of white X‐rays is described by taking the instrumental resolution into account. A high‐power X‐ray generator was used to generate white X‐rays. The short‐range‐order (SRO) diffuse scattering from Au4Mn alloy was measured and the Warren–Cowley SRO parameters of this alloy were determined up to the 50th shell. The results are in good agreement with those obtained by the angle‐dispersive technique. Possible application of this method with the use of X‐rays from a synchrotron radiatio

ISSN:1600-5767    

DOI:10.1107/S0021889884010906

出版商:International Union of Crystallography    

年代:1984

数据来源: WILEY

摘要:

The vertical intensity distributions of X‐rays from a synchrotron source are measured by powder diffraction. The components polarized in the orbital plane and perpendicular to this plane are separated by measuring a reflection 90° to the vertical and horizontal planes, respectively. The measurements are made at three wavelengths between 0.65λcandλc, whereλcis the characteristic wavelength. In each case, the degree of linear polarization reaches a maximum of 90% at the center of the beam. The results agree closely with calculations which use machine optical param

ISSN:1600-5767    

DOI:10.1107/S0021889884010918

出版商:International Union of Crystallography    

年代:1984

数据来源: WILEY

摘要:

It is shown by a diffraction technique that 2‐naphthalenethiol (C10H8S) undergoes a first‐order phase transition which occurs at 313 ± 0.5 K. The low‐temperature form III is ordered whereas the high‐temperature one I is disordered and may be kept as metastable far below 313 K. Thermal expansion studies, performed on the stable form III and on both metastable and stable forms I, indicate that: form III exhibits a pronounced `pretransitional' effect; discontinuities of the lattice constants occur at the III →I transition; the lattice‐constant thermal‐expansion curves of form I do not show any inflexion at the metastable to stable transition; in every case a large thermal expansion anisotropy is observed. Curiously, the compacity of the ordered low‐temperature form is lower than that of the disordered high‐temperature form. The JCPDS Diffraction File No. of the low‐tempera

ISSN:1600-5767    

DOI:10.1107/S002188988401092X

出版商:International Union of Crystallography    

年代:1984

数据来源: WILEY

摘要:

The proposed method is aimed at the analysis of phase distribution in thin surface layers comparable to the penetration depth of X‐rays. The phase distribution is modelled mathematically and the parameters of the distribution are evaluated from diffraction data taken for various peaks and with various radiations. The method was applied to the analysis of austenite distribution in cathodically charged stainless stee

ISSN:1600-5767    

DOI:10.1107/S0021889884010931

出版商:International Union of Crystallography    

年代:1984

数据来源: WILEY

摘要:

Several procedures for Fourier analysis of single diffraction peaks for microstrains and mosaic sizes are compared. A simple new method works well, especially when the size distribution is broad, and/or when the strains vary in an unusual manner.

ISSN:1600-5767    

DOI:10.1107/S0021889884010943

出版商:International Union of Crystallography    

年代:1984

数据来源: WILEY

摘要:

A convenient approximation has been obtained for the intensity of the small‐angle X‐ray or neutron scattering from an assembly of independently scattering spherical particles with constant density when the radius‐distribution function is a Gaussian with a full width at half maximum which is not greater than 1.7 times the most probable radius. The approximation expresses the intensity in terms of elementary functions. Criteria are given for setting a bound on the error in the approxim

ISSN:1600-5767    

DOI:10.1107/S0021889884010955

出版商:International Union of Crystallography    

年代:1984

数据来源: WILEY

摘要:

The energy‐dispersive X‐ray diffraction method has been used to measure integrated Bragg intensities from TaDxsingle crystals as a function of D concentration and scattering vector. The observed attenuation can be described in terms of a thermal and a static Debye–Waller factor (DWF). From the static DWF, for small scattering vectors, the displacementsu1= 0.095 (5) Å of the four Ta atoms closest to the D atom are obtained and, for large scattering vectors, the change of the mean‐square thermal displacement of these atomsΔv21= −[5.5

ISSN:1600-5767    

DOI:10.1107/S0021889884010967

出版商:International Union of Crystallography    

年代:1984

数据来源: WILEY

摘要:

A computer program for unambiguous and consistent indexing of a series of single‐crystal diffraction patterns is discussed which allows determination of the unit triangle and therefore tilting of the specimen into any special orientation even if no Kikuchi patterns can be observe

ISSN:1600-5767    

DOI:10.1107/S0021889884010980

出版商:International Union of Crystallography    

年代:1984

数据来源: WILEY

摘要:

A new direct‐methods computer program,MITHRIL, is described. Written in a neutral subset of Fortran IV, it is built around a heavily modifiedMULTAN80 system. It incorporates many recent theoretical developments in direct methods including the use of quartet and quintet invariants, a new method for estimating triplets,YZARCandMAGEX, and random‐phase tangent refinement. It can be run as a menu‐driven interactive real‐time package or in the more conventional batch mode. Several levels of user‐program interaction are

ISSN:1600-5767    

DOI:10.1107/S0021889884010992

出版商:International Union of Crystallography    

年代:1984

数据来源: WILEY