ISSN:0232-1300    

DOI:10.1002/crat.2170240115

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractTris‐sarcosine calcium chloride (TSCC) single crystals were grown from water solutions by the isothermal evaporation method. The growth solutions contained sarcosine and CaCl2either in stoichiometric or nonstoichiometric ratio. The required phase diagram sarcosine–CaCl2H2O at 40 °C was determined by the synthetic method. PFT 400 MHz NMR was used for the analysis of organic impurities in sarcosine and TSCC. The crystals grown from both types of solutions had maximum values of the dielectric permittivity 10 to 200 times larger than those measured by other authors at comparable measuring frequencies and fields. It is discussed in terms of crystal q

ISSN:0232-1300    

DOI:10.1002/crat.2170240116

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170240117

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractData characterizing the stability of basic dielectric properties against thermal treatement are presented for crystals of TGS and deuterated TGS doped with alanine or bivalent platinum. Complex permittivity and over‐all polarization have been measured during a heating‐cooling cycle. In alanine doped crystals the heating and cooling curves are perfectly reproducible. In Pt‐doped samples the reproducibility is worse, for pure TGS the properties on cooling are strongly influenced by domain effects. These data made it possible to estimate the change of the figures of merit for pyroelectric ir detectors due to transient he

ISSN:0232-1300    

DOI:10.1002/crat.2170240118

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170240119

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractResults on the thermoluminescence following incorporation of a wide range of dopant materials in calcium sulphide are reported. These results are compared with those previously reported in the literature. Factors such as fluxes and preparation technique are varied to determine their effect on the TL spectra. Conclusions regarding the possible source of the traps causing the TL in CaS are drawn with the evidence suggesting natural defects as the source of the traps; the added dopant impurities having only a secondary effect on the thermoluminescence peak temperatures.

ISSN:0232-1300    

DOI:10.1002/crat.2170240120

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractAn example is given for the development of a nematic two frequency addressing mixture based on the equations for the threshold voltages, the switching times, and the dielectric relaxation. New substances have been synthesized with relaxation frequencies in the kHz range and big values of the static dielectric anisotropy at room temperature. The isotropy frequency and the relation between the high and low frequency dielectric anisotropy, respectively, are adjustable by adding of substances without a relaxation mechanism in the kHz range and with a big negative static dielectric anisotropy. The produced mixture was dielectrically investigated. Calculated and experimentally found data are in a good agreement.

ISSN:0232-1300    

DOI:10.1002/crat.2170240121

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

摘要:

AbstractThe change of the sign of the dielectric anisotropy of a nematic liquid crystal allows an active switching process in electrooptical cells in on and off direction. In the two frequency addressing mode the TN cell shows a qualitative and quantitative different dynamic behaviour in comparison to the conventional driving mode. During the switching on process hydrodynamical domains occur. After switching off the director configuration skips into the −3π/2 twist and thereby it realizes a loss in transmission. The director configuration relaxes into the quarter twist after some minutes. A superposition of low frequent and high frequent voltage gives a strong increase of the number of multiplexable lin

ISSN:0232-1300    

DOI:10.1002/crat.2170240122

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY

ISSN:0232-1300    

DOI:10.1002/crat.2170240101

出版商:WILEY‐VCH Verlag    

年代:1989

数据来源: WILEY