ISSN:0023-4753    

DOI:10.1002/crat.19760110402

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractOn the basis of the LPE GaAs growth rate measurements in which we used current marks of time, the diffusion coefficient and the critical supercooling of arsenic in Ga solution by a semiempirical method was determined. Some knowledge of these parameters is indispensable for investigating the growth mechanism and kinetics of epitaxial layers from high temperature solutions. Taking into account the fact that the diffusion coefficient as a function of temperature is of the formD(T) =D0· exp (–B/T), the results were extrapolated in a range of temperatures 750–950°C typical for liquid epitaxy of

ISSN:0023-4753    

DOI:10.1002/crat.19760110403

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractX‐ray and electron microprobe analyses of Sb(S, O)I films structure and composition have been performed. The films under investigation were prepared by crystallization from the melt in close spacing. It was revealed that the SbS0.8O0.2I structure was isomorphic t the SbSI one. The ferroelectric phase transition was observed at 75°C. The electromechanical coupling factor was 0.3 at 50

ISSN:0023-4753    

DOI:10.1002/crat.19760110404

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractDie Aggregatbildung in technischen Kristallisatoren ist ein wichtiges Element der technischen Kristallisation. Die Untersuchung dieses Vorgangs ist experimentell sehr schwierig. Es wird eine Einrichtung zur direkten Beobachtung der Aggregatbildung in gerührten Lösungen beschriebe

ISSN:0023-4753    

DOI:10.1002/crat.19760110405

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractA new method for the determination of the orientation of organic molecules with partially known stereochemistry in the unit cell is described and compared with the convolution molecule method by Hoppe and Paulus.

ISSN:0023-4753    

DOI:10.1002/crat.19760110406

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractA method for the exact determination of the orientation of the molecules in a crystalline organic structure by X‐ray analysis is described. The Eulerian angles are refined by a special rigid body least squares procedure. The theoretical background is give

ISSN:0023-4753    

DOI:10.1002/crat.19760110407

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractThe critical behaviour of TGS and isomorphous DTGS, TGSe and DTGSe single crystals grown at various conditions was investigated. The growth dependences for ΔTin heating and cooling regimes and shift ΔTof the temperature of maximal permittivity were found. These dependencies were explained in terms of existence of internal biasing fields these being measured vs temperatur

ISSN:0023-4753    

DOI:10.1002/crat.19760110408

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractA new method for the visualization of domain and real structure of ferroelectric triglycine sulphate (TGS) crystals on the scale of optical microscopy by means of decoration with auramine is developed. Auramine deposits on crystal surfaces as discrete particles about 2 microns in size and as a continuous layer, thus allowing both the domains as a whole and the various electrically active elements of the domain and real TGS structure to be visualized with high resolution. Due to decoration with auramine, the domain structure of TGS detected with a very high contrast; elements of the geometrical relief‐cleavage steps exhibiting different electrical properties are also revealed. Furthermore, it has been observed for the first time that the positive domains have sharp electrical boundaries, while the negative domains have erased boundaries. It has also been established that between the domains of opposite signs regions exist characterized by a very low electrical activity. Decoration of annealed TGS crystals which were rapidly cooled from the temperature of 150°C, i.e. above the Curie point (49°C) down to room temperature resulted in detection of new electrically active directions on the surface of the negative domains; these directions are likely to occur in the paraelectric state. The new method cannot only be applied to the study of the TGS crystals but can also be useful in investigation of other ferroelectr

ISSN:0023-4753    

DOI:10.1002/crat.19760110409

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractIn the present work neutron diffraction study is made of the ordering effekt within the whole region of the existence of the γ‐phase of the Al‐Mg system. Depending on thermal treatment conditions, the order coefficient S varies from 0.15 to 0.7 for compounds containing 59 and 60 at.% Mg at temperatures ∼330 and below 150°C, respectively. – At decreased annealing temperatures the ordinate of the highest ordering is shown to approach the composition which may be approximately characterized as Al2Mg3. The temperature increase results in the decrease of the ordering degree, and the ordinate of the highest ordering displaces to the composition which may be expressed as Al12Mg17. – Kurnakov's point is determined which is lying at ∼330°C for the composition contain

ISSN:0023-4753    

DOI:10.1002/crat.19760110410

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY

摘要:

AbstractIron whiskers grown by hydrogen reduction of ferrous chloride were studied by several X‐ray and optical techniques, particularly by X‐ray diffraction topography. 36 whiskers with [100], [110]and [111] axis directions, from 20 μm to 260 μm in thickness were investigated. They were of different degree of perfection with dislocations nonuniformly distributed. Three [111]whiskers showed a lattice twist around the axis. Burgers vectors of several frequent types of dislocations were

ISSN:0023-4753    

DOI:10.1002/crat.19760110411

出版商:WILEY‐VCH Verlag    

年代:1976

数据来源: WILEY