摘要:

The microabsorption of X‐rays scattered by isotropic powder samples is studied for nonsymmetric beam geometry including grazing incidence. Experimental results for the absorption effect and its dependence on both the incidence and scattering angles are presented. The absorption behaviour is qualitatively explained by means of a simple surface‐roughness mo

ISSN:1600-5767    

DOI:10.1107/S0021889892009257

出版商:International Union of Crystallography    

年代:1993

数据来源: WILEY

摘要:

The cryostat for 8

ISSN:1600-5767    

DOI:10.1107/S0021889892009269

出版商:International Union of Crystallography    

年代:1993

数据来源: WILEY

摘要:

A computer program,POLISH, is presented that improves the accuracy of the structure‐factor magnitudes obtained from powder data. This offers a greater likelihood of success for structure determination by direct methods or Patterson techniques. Generally, the program will be used in conjunction with a unit‐cell refinement program, but it may also be used independently. Accurate values of the unit‐cell and peak‐shape parameters are required, which may be conveniently obtained from the unit‐cell‐refinement program. The program is tested by application t

ISSN:1600-5767    

DOI:10.1107/S0021889892007611

出版商:International Union of Crystallography    

年代:1993

数据来源: WILEY

摘要:

A new version of the programDIFK[Weiss, Krajíček, Smrčok&Fiala (1983).J. Appl. Cryst.16, 493–497] has been developed for use on an IBM‐compatible personal computer (PC). The main strengths of the program are (i) calculation of the diffraction patterns of mixtures of up to five phases, (ii) searching for real maxima resulting from the coincidence of several diffractions, (iii) modelling the influence of preferred orientation and (iv) the performance of these calculations for different diffraction geometries. Besides a standard printout the program also produces files in the HPGL

ISSN:1600-5767    

DOI:10.1107/S0021889892008070

出版商:International Union of Crystallography    

年代:1993

数据来源: WILEY

摘要:

A reminder is given that ignoring correlations between fractional coordinates in an oblique coordinate system can lead to inaccuracies in the estimation of standard deviations of bond lengths and other derived quantities. Methods based on a paper by Templeton [Acta Cryst.(1959),12, 771–773] are suggested to make approximate allowance for the effect when the parameter variance matrix is unavailabl

ISSN:1600-5767    

DOI:10.1107/S0021889892011774

出版商:International Union of Crystallography    

年代:1993

数据来源: WILEY

ISSN:1600-5767    

DOI:10.1107/S0021889892007751

出版商:International Union of Crystallography    

年代:1993

数据来源: WILEY

ISSN:1600-5767    

DOI:10.1107/S0021889892008355

出版商:International Union of Crystallography    

年代:1993

数据来源: WILEY

ISSN:1600-5767    

DOI:10.1107/S0021889893099650

出版商:International Union of Crystallography    

年代:1993

数据来源: WILEY