ISSN:0232-1300    

DOI:10.1002/crat.2170231002

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe kinetics of overall isothermal crystallization of the amorphous Fe75B25alloy, as well as the kinetics of nucleation and growth in amorphous Fe75B25and Fe80B20alloys were investigated with the aid of a thermomagnetic balance. The activation energies of growth for both alloysQG= 167 kJ/mol, which are similar to these, found by other authors, were determined. Curves number of nucleiNvs timetwere traced and the activation energy of nucleation in the amorphous alloy Fe80B20was obtainedQN= 211 kJ/mol, which value is also in very good agreement with those determined by means of other independent methods.

ISSN:0232-1300    

DOI:10.1002/crat.2170231003

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractPreparation of vapour grown platelet shaped α‐HgI2crystals is discussed. Total pressure, temperature profile and ampoule configuration influence the yield of the process, deposition pattern, crystal shape and morphology. Growth conditions (vapour flow and surface processes) are more important for platelets formation then nucleation on the ampoule's walls. A source temperature of 150–180 °C, total pressure of 2–10 Torr at RT and horizontal configuration of the ampoule create advisable conditions for platelets

ISSN:0232-1300    

DOI:10.1002/crat.2170231004

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170231005

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe mass transport rate of HgI2in closed ampoules with the addition of He, Ar or Xe at different pressures (20–200 Torr) was gravimetrically measured. Diffusive and convective mass fluxes in the systems studied were calculated according to vapour transport models. The influence of technological parameters, i.e. temperature, pressure, kind of added gas, and ampoule diameter, on the mass transport of HgI2vapour was studied. Mechanisms of vapour flow in the applied experimental conditions are discusse

ISSN:0232-1300    

DOI:10.1002/crat.2170231006

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe hydrothermal treatment of faujasite‐type zeolites in water, water vapour or weak acidic resp. alkaline solution usually leads to a pseudomorphous phase transformation. The process starts near the surface and penetrates the crystal. Due to the small reaction rate of the transformation as long‐time process the new material grows within the geometry of the dissolving zeolites. Therefore their crystal morphology is unchanged. The reaction mechanism of phase transformations is discus

ISSN:0232-1300    

DOI:10.1002/crat.2170231007

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractPlanar oriented samples with positive dielectric anisotropy were used to study the dielectric reorientation in SIphases. It was found that the dielectric reorientation is characterized by the rotation of the molecule director around the layer normal. The field‐induced deformations do not arise simultaneously in the whole sample but they start in certain regions and grow continuously by domain wall motion. Depending on the boundary conditions three types of field‐induced deformations can be observed at different thresholds. An attempt has been made to interprete this behaviour on the basis of a simple mo

ISSN:0232-1300    

DOI:10.1002/crat.2170231008

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170231009

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractA new homologous series of swallow‐tailed compounds possessing terminal cyano groups was synthesized. These substances form nematic phases with a relatively small negative dielectric anisotropy. In electric fields planar oriented samples of these compounds exhibit domain instabilities of different kind depending on the experimental condition

ISSN:0232-1300    

DOI:10.1002/crat.2170231010

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170231011

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY