摘要:

AbstractStep response functions are introduced to describe the nonstationary mass transfer in MOVPE AlGaAs growth. The solutions of direct problem and inverse one of the control of solid solution composition are presented.

ISSN:0232-1300    

DOI:10.1002/crat.2170250108

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractInvestigation has been carried out on the effect of the surface activity of capillary or surface active substances (impurities), called surfactants (i.e. the effect of the lowering (Δσ) of the specific surface energy after impurity adsorption at the solid/gas, solid/liquid, liquid/gas or liquid/liquid interface), on the thermodynamic equilibrium in a polydisperse system. Attention has been paid to the fact that the presence of a surfactant with an activity within the range 0<Δσσ0) that σa= σ0− Δσ<0 (σa, specific surface energy of the interface in the presence of a surfactant), is of special interest. It represents a paradox in the phase formation theory: as a result of the adsorption of an impurity with such a high activity, the condensed phase surface would be destabilized and the phase would

ISSN:0232-1300    

DOI:10.1002/crat.2170250109

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractIt was investigated the contribution of diffusion‐induced structural changes on the anisotropy of P diffusion into the monocrystalline Si. Generation and distribution of dislocations by solute diffusion of phosphorus in silicon (100) and (111) provides for further different depth penetration of diffusion precipitation up to anisotropic diffusion in cubic crystal

ISSN:0232-1300    

DOI:10.1002/crat.2170250110

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe amorphous to crystalline transitions in InSe films have been investigated by different techniques. InSe compound was prepared from non‐stoichiometric amounts of indium and selenium in vacuum. The electrical conductivity and thermoelectric power measurements were made in films of different thicknesses and annealed for different times. TEP studies revealed that the films are p‐type. The conductivity studies have shown transition from amorphous to crystalline. The transition temperature is found to decrease with increase in (i) the thickness of the film, (ii) the time of annealing. Electronmicrographs and selected area diffraction patterns on as‐grown and annealed films have been taken and correlated with the conductivity results. The mechanism involved in the amorphous to crystalline transitions has been disc

ISSN:0232-1300    

DOI:10.1002/crat.2170250111

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractInfrared reflectivity spectra of In2O3samples pressed from powdered material are measured at room temperature in the wavenumber range from 180 to 4000 cm−1. A Kramers‐Kronig analysis of the spectra reveals eleven vibrational modes. The results obtained are compared with group theoretical predictions and with existing experimental d

ISSN:0232-1300    

DOI:10.1002/crat.2170250112

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe specific conductivity of saturated aqueous solutions of KH2PO4and its solubility are investigated in the pH range between 2.5 and 6.3. It is found that the values of specific conductivity and solubility show minima at pH of about 3.5 and 4, respectively. These observations are discussed in terms of the presence of a variety of species of different concentrations in saturated solutions of different pH. The conductivity data reveal that the solutions are highly associated. The presence of species other than H2PO4−and K+explains the experimentally observed deterioration in the quality of KDP crystals from solutions of pH deviating from the natural valu

ISSN:0232-1300    

DOI:10.1002/crat.2170250113

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe formation of etch patterns on dislocations in potassium bichromate (KBC) crystals has been studied. It was found that, depending on the relative position of a dislocation line with respect to the etching plane, either a groove or a groove associated with a pit or a pit alone are formed. A dislocation lying in the etching plane or not much inclined from it gives a groove or an array of etch pits. An inclined dislocation gives a groove connected with an eccentric pit and a normal one gives a centric pit. A dislocation to be revealed as an etch groove has to lie sufficiently close (<100 μ) to the observation plane

ISSN:0232-1300    

DOI:10.1002/crat.2170250114

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170250115

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractDynamic etching of natural rhombohedral calcite cleavage plane in low concentration of monocarboxylic acid (such as formic, acetic and propionic acids) is studied and interesting results are obtained. Eccentricity of rhombic etch pits increase indefinitely as stirring rate increase in low concentration of monocarboxylic acids, whereas peak value of eccentricity is obtained with stirring rate when there is a change in etch pit morphology. Change in etch pit morphology and change in eccentricity with stirring rate is explained with the help of lateral reaction rates along various directions. Eccentricity variation with stirring rate is compared with concentration variation with concentration of different monocarboxylic acids.

ISSN:0232-1300    

DOI:10.1002/crat.2170250116

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY

摘要:

AbstractThe microhardness of Hg1−xCdxTe and Hg1−xZnxTe has been measured on monocrystalline samples of Bridgman and THM crystals as a function of compositionxby means of Vickers indentation measurements at room temperature. The curves show maxima of about 830 MPa atx≈︁ 0.75 for Hg1−xCdxTe and of about 1700 MPa in the range 0.65 ≦x≦ 0.8 for Hg1−xZnxTe. The hardness‐relaxation behaviour has been measured on {111} samples in order to obtain the internal stress level and to investigate the stress‐relaxation behaviour. The theoretical hardening ratedH/d(x)0.5was compared with

ISSN:0232-1300    

DOI:10.1002/crat.2170250117

出版商:WILEY‐VCH Verlag    

年代:1990

数据来源: WILEY