摘要:

AbstractOn the basis of1the experimental observation of dislocation loops by means of TEM,2the conclusion from this that the concentration of vacancies in the dislocation loops exists at the cost of the vacancy concentration primarily present atTq, and3the inversion of the decomposition kinetics of Al–Zn–Mg alloys found out by means of resistivity and microhardness measurements, the effective vacancy concentrationcv.effbeing at disposal for the GP‐zone formation was found out by means of the relationtR,max(tR,maxbeing the time required to reach the maximum of resistivity) and the Arrhenius plot IntR,max=f(1/Tq) of the isothermal resistivity measurements. From the comparison ofcv.effwith the theoretical V concentration atTqit is possible to derive statements about the loss of vacancies during and after the quench through loop formation, building‐in of vacancies in GP‐zones and annealing of vacancies at lattice defects.From this comparison follows:The ideal ZnV concentration atTq(calculated by means of the Lomer equation) is sufficiently great to account for the effective vacancy concentration.The part ofcMgVin the loss concentration is rising with increasingcMg.Both these statements support the hypothesis that the initial process of the decomposition in Al–Zn–Mg alloys is caused by the

ISSN:0232-1300    

DOI:10.1002/crat.2170260117

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractThin films of various thicknesses in the MIM structure have been prepared from the the powders of SnO2, Sb2O3and (SnO2+ Sb2O3) of high purity by the thermal evaporation technique in a vacuum of 10−5Torr. Dielectric properties of SnO2, Sb2O3, and their mixed thin films have been studied with ac and dc electric fields and frequency. Capacitance and loss tangent are almost independent on dc voltage upto 1.0 V for SnO2, 10.0 V for Sb2O3and 2.5 V for mixed films. These capacitors become unstable at 1.0 V for SnO2films and 2.5 V for mixed films. For higher film thicknesses the decay in these films starts at higher voltages. Capacitance and loss tangent increases with applied ac voltage in SnO2, Sb2O3, and their mixed films. A comparison of the capacitance values of SnO2, Sb2O3, and their mixed films showed that the capacitance values are less in Sb2O3as compared to SnO2films. In mixed films the capacitance is greater than the constituent films. These studies have shown that Sb2O3films are found to be more stable compared to SnO2and their mixed films for ac and dc voltages. The results thus obtained on SnO2, Sb2O3, and their films are presented and discusse

ISSN:0232-1300    

DOI:10.1002/crat.2170260118

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractPhotoconductivity spectra of n‐type CuInSe2single crystals are measured in the photon energy rangehv= 0.75 – 3.1 eV and as a function of temperature in the rangeT= 80 – 320 K. It is found that the photoconductivity of as‐grown crystals is a nearly pure surface effect, while sensitization of the crystal volume is observed only after sufficiently long annealing in the presence of powdered material. To explain the temperature dependence of the photoconductivity carrier trapping processes must be taken into

ISSN:0232-1300    

DOI:10.1002/crat.2170260119

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractUsing various Q switching techniques the performance potential of some Nd: glass rods have been analysed and compared with that of a standard rod. Second harmonics generated from such a Q‐switched system have been separated from the fundamental using suitable dispersive elemen

ISSN:0232-1300    

DOI:10.1002/crat.2170260120

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractCalibration curves to determine P, B, and Al concentrations in silicon at 4.2 K from the intensity ratios of bound (BE) and free (FE) exciton related luminescence are presented. The integral relative intensities of the peaks are used besides the peak height ratios. By means of a large number of samples with widely varying concentrations it is shown that the influence of the compensation ratios of the samples on the determination of the dopant concentrations is smaller than the measurement errors. Integral intensity ratios of different BE phonon branches are also derived.

ISSN:0232-1300    

DOI:10.1002/crat.2170260121

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractIn single crystals of scapolite from two different localities, three paramagnetic centres are detected by electron paramagnetic resonance (EPR): 1. One isotropic singlet withgiso= 2.005; 2. One triclinic singlet withg‖ = 2.005 ± 0.001 andg⟂= 2.009; 3. One triclinic sextet withg‖= 2.005 ± 0.001,g⟂ = 2.011;A‖ = 85.4 × 10−4cm−4,A⟂ = 85.3 × 10−4cm−1.Centres 1 and 2 can be attributed to colour centres as they are bleached after annealing.Centre 3 can be due to Mn2+(only the central Ms= ± 1/2 transition is observable) most likely substituting for Ca2+The site symmetry must be triclinic but due to Al, Si disorder and mixed Na, Ca composition the different components from magnetically non‐equivalent sites are averaged

ISSN:0232-1300    

DOI:10.1002/crat.2170260122

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

摘要:

AbstractLarge heated substrates in industrial MBE application offer the possibility to minimize the influence of shutter motion on the evaporation source temperature by shutter installation at the position of zero net flux of radiation, which is discussed in the present paper.

ISSN:0232-1300    

DOI:10.1002/crat.2170260123

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170260101

出版商:WILEY‐VCH Verlag    

年代:1991

数据来源: WILEY