ISSN:0232-1300    

DOI:10.1002/crat.2170250322

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170250323

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170250324

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170250325

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170250326

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe effect of diffusion in the vapour phase on the kinetics of growth of zinc single crystals in the presence of argon has been studied. The shift of the basal face in normal direction as a function of the time has been measured at constant temperature and supersaturation and argon pressures varying within the range 5–250 Torr as well as in vacuum 1 × 10−6Torr. It has been established that the crystal sizeRchanges with the timetfollowing a linear and a parabolic law in the kinetic and the diffusion regimes, respectively. The kinetic critical sizeRkfor the transition from a kinetic to a diffusion regime has been experimentally obtained. A relatively good agreement is found between the experimentally established and theoretically calculated values of the critical size. The problems related to the transition of the basal faces of zinc single crystals from a kinetic to a diffusion growth mode is discu

ISSN:0232-1300    

DOI:10.1002/crat.2170250302

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe growth kinetics of the edge of the basal face of zinc single crystals grown from a vapour phase under diffusion controlled conditions has been investigated. The growth of the basal edge with time at constant temperature and supersaturation and argon pressures between 5 and 250 Torr or in vacuum 1 × 10−6Torr has been plotted. It is established that the lengthaof the edge of the {0001} face is changed with timetaccording to a linear and a parabolic dependence. The kinetic critical sizeakis determined by the intersection point between the two parts ofa2(t) curves. It is shown that the results from the kinetic investigations of the basal face edge are in qualitative agreement with the basic relationships characterizing the growth kinetics of crystals in a kinetic and a diffusion regime Experimental facts are presented (e.g. the parallel runninga2(t) curves, etc.) which confirm the diffusion character of the observed transition of the basal edge of zinc single crystals from a kinetic regime to a diffusion growth mo

ISSN:0232-1300    

DOI:10.1002/crat.2170250303

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractPhysical parameters, i.e. the effect of temperature and time of crystallization on the content of zeolite ZSM‐5 in the obtained preparations were investigated. Two standard reacting mixtures were tested. The mixture of ethanol and ammonia was used as a templating agent. The phase composition of the preparations was determined on the ground of the X‐ray diffraction met

ISSN:0232-1300    

DOI:10.1002/crat.2170250304

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe preparations, precipitations and recrystallisations of magnesium and calcium aluminosilicate hydrates, from aqueous suspensions of microcrystalline silica, aluminium hydroxide (and oxohydroxide) and magnesium (calcium) hydroxides at ambient temperatures to 400 °C, are surveyed. The phases reported in systems of different Mg(Ca)/(Al + Si) and Al/(Al + Si) composition ratios are tabulated and precipitation and recrystallisation mechanisms are proposed

ISSN:0232-1300    

DOI:10.1002/crat.2170250305

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170250306

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY