摘要:

The variance of a line profile as a measure of the breadth of the line has recently been given a sound theoretical basis and a computer program is described to perform the enormous amount of computation required in variance analysis.

ISSN:1600-5767    

DOI:10.1107/S0021889869006960

出版商:International Union of Crystallography    

年代:1969

数据来源: WILEY

摘要:

Electron microscope experiments show that the mechanism of electron‐induced decomposition of tin(IV) sulfide differs from that of thermal decomposition. Hexagonal tin(IV) sulfide is converted to tetragonal tin in three equivalent orientations with [100]Snparallel to [100]SnS2and [001]Snparallel to [001]SnS2. Experiments on epitaxic growth of tin on tin(IV) sulfide (001) surfaces and theoretical considerations of relative interface energies show that the reaction is controlled by epitaxy and not by a three‐dimensional relation between the two latti

ISSN:1600-5767    

DOI:10.1107/S0021889869006972

出版商:International Union of Crystallography    

年代:1969

数据来源: WILEY

摘要:

A method is presented which combines the analysis of X‐ray absorption profiles and selected area X‐ray topographs. The method is based on X‐ray divergent beam patterns obtained in transmission. The absorption profiles are obtained by unfolding the spectral distribution from the profiles of the deficiency conics, whereas the selected area topographs derive from the corresponding diffraction conics. The synergy of the two techniques makes the method particularly useful for the elucidation of anisotropic effects and inhomogeneities of defect structures. An example is given for the room temperature deformation of bery

ISSN:1600-5767    

DOI:10.1107/S0021889869006984

出版商:International Union of Crystallography    

年代:1969

数据来源: WILEY

摘要:

The theory of single and multiple small‐angle scattering of fibres with a two‐phase system of densities is revised. Luzzati's fundamental treatment of multiple scattering has been applied to systems with cylindrical symmetry. It is shown that the results of measurements with an `infinite' slit parallel to the fibre axis cannot give the specific internal surface directly, but that this information can be obtained by a combination of `infinite' slit measurement and measurements with a pin‐hole system in the case of needle‐like pores with preferred orientation. The experimental results obtained indicate that the scattering at very small angles is a multiple scattering determined by the filament cross‐section. It is shown that parameters related to the size and the shape of the filament cross‐section as wall as the specific surface of the filaments can be computed from this scattering. The scattering at somewhat wider angles is essentially a single scattering and can contain two components. The predominant component is a scattering of needle‐like pores with diameters in the 10–20 Å range and lengths of at least 200–300 Å. The porosity is around 30%. The needle axes show a preferred orientation parallel to the fibre axis. The angular distribution of the needle axes is very similar to that of the graphitic layers. A second component can be observed, which is produced by density fluctuations in the parallel stacking of graphitic layers. Studies on powdered fibres indicate changes in the microstruct

ISSN:1600-5767    

DOI:10.1107/S0021889869006996

出版商:International Union of Crystallography    

年代:1969

数据来源: WILEY

摘要:

X‐ray diffraction measurements have been made at three compositions in the Bi–In system. Each alloy was investigated in the liquid phase at two temperatures, 10°C above the liquidus and 499°C. Partial density functions were calculated by assuming that the like partial interference functions are the same as those of the pure components. Partial coordination numbers obtained from these density functions lead to the conclusion that the liquid alloys are very similar to a disordered mixture of Bi and In

ISSN:1600-5767    

DOI:10.1107/S002188986900700X

出版商:International Union of Crystallography    

年代:1969

数据来源: WILEY

摘要:

An X‐ray reflexion topography camera has been designed to study structural defects near the surface of monocrystalline semiconductors. Large surfaces can be covered by means of successive fixed exposures. A surface of 30 mm x 10 mm for example can be studied in less than ten minutes on nuclear emulsions. The conditions for the observations of dislocations in gallium arsenide have been examined: the choice of reflecting planes is limited by the depth of penetration of X‐rays, so that the effective crystal thickness must be of the order of the width of a dislocation image (2‐5 microns). Studies to which these observations can be applied are numerous: structural defects induced by diffusion, lattice strains, orientation of dislocations near the surface, structural evolution of silicon during integrated circuits elaboration, structure of cleavage surfaces, lapping and polishing defects, structural defects of epitaxic

ISSN:1600-5767    

DOI:10.1107/S0021889869007011

出版商:International Union of Crystallography    

年代:1969

数据来源: WILEY

摘要:

By the application of Sawyer and Tower's method it has been observed for the first time that NaU2(PO4)3single crystals possess ferroelectric properties. Hysteresis loops were recorded and ferroelectric parameters were determined at room temperature. The measurements were performed on very small single‐crystal samples with an area of about 1  mm2and 0.05 mm

ISSN:1600-5767    

DOI:10.1107/S0021889869007023

出版商:International Union of Crystallography    

年代:1969

数据来源: WILEY

ISSN:1600-5767    

DOI:10.1107/S0021889869007047

出版商:International Union of Crystallography    

年代:1969

数据来源: WILEY

ISSN:1600-5767    

DOI:10.1107/S0021889869007072

出版商:International Union of Crystallography    

年代:1969

数据来源: WILEY

ISSN:1600-5767    

DOI:10.1107/S0021889869007096

出版商:International Union of Crystallography    

年代:1969

数据来源: WILEY