电控平行排列液晶光栅的光衍射特性研究

对电控平行液晶光栅的理论进行了分析,并配以结构原理图。通过对平行排列及90°扭曲排列液晶指向矢的计算,得出液晶盒中相应的折射率、相位差与电压之间的关系图,两者经比较证明平行排列更具适用性,并在实验中观测到了平行排列液晶光栅衍射特性与电压的关系。     

棒状液晶分子相变问题的机械旋转模型研究

综述一种关于棒状液晶材料的分子结构与液晶相的相关关系的研究成果。介绍了有关液晶分子的机械旋转模型。该模型将液晶分子视作一种高速旋转的转子,通过分子参数计算,对液晶材料的相变温度和分子结构之间的关系给出了一种全新的解释。最新研究表明,含氟三苯液晶材料的分子结构中存在slim和fat现象,能够对液晶材料的相变进行合理解释。该模型能够通过简单的模型方法对新型液晶材料的分子设计与合成提供有用的信息。     

An analysis of the electrical conductivity in BaSO4-added Ag2SO4 solid electrolyte system

The compositions (1 −x)Ag₂SO₄−(x)BaSO₄, wherex=0·01 to 0·6, were prepared by slow cooling of the melt. The extent of the solid solubility of Ba²⁺ in Ag₂SO₄ was determined by X-ray powder diffraction and scanning electron microscopy. The bulk conductivity of each sample was obtained using a detailed impedance analysis. The partial substitution of Ba²⁺ results in the enhancement of conductivity in compliance with the classical aliovalent doping theory. A simplistic model based on lattice distortion (expansion) due to partial substitution of Ag⁺ by the bigger Ba²⁺ has been considered to explain enhanced conductivity. Beyond solid-solubility limit (5·27 mole%) the BaSO₄-dispersed Ag₂SO₄ conductivity follows the usual trend seen in binary systems. An increase in conductivity in this case is discussed in the light of interfacial reactions and surface defect chemistry. The maximum conductivity in 20 mole% BaSO₄ dispersed Ag₂SO₄ is due to percolation threshold.     

液晶基元直接横挂于主链上的液晶共聚物的合成与研究

以含液晶基元的单体２，５－双（４－甲氧基苯甲酰氧基）苯乙与苯乙烯通过自由基共聚合反应，首次合成了一系列含液晶性和非液晶性两种序列结构的共聚物。采用ＤＳＣ、偏光显微镜和Ｘ衍射方法研究了共聚物的液晶行为，发现单体和共聚物（只有ＣＰ－５和ＣＰ－６）有很好的热致液晶性。随共聚物中介晶单体单元含量的增加，共聚物玻璃化转变温度Ｔ和热分解温度Ｔ呈规律变化。     

Transport of chromium(VI) through a Cyanex 921‐supported liquid membrane from HCl solutions

The transport of chromium(VI) through a flat‐sheet supported liquid membrane containing Cyanex 921 as a carrier has been investigated. The permeation of the metal is investigated as a function of various experimental variables: hydrodynamic conditions, concentration of chromium(VI) and HCl in the feed phase, carrier concentration and diluent in the membrane and strippant concentration in the stripping phase. The mass transfer coefficient and the thickness of the aqueous boundary layer were calculated from the experimental data. Furthermore, the selectivity of Cyanex 921‐based flat‐sheet supported liquid membrane towards different metal ions and the behaviour of the system against other carriers are presented. Copyright © 2003 Society of Chemical Industry     

Micellar polymerisation of ionic surfactants studied by conductimetry

The micellar polymerisation of ionic surfactants such as allyldodecyl-dimethylammonium bromide and 3-dodecyl-1-vinyl imidazolium iodide has been studied by conductimetry in aqueous solution. The polymerisation was carried out using two different sources of γ rays directed into solutions of surfactant above the critical micellar concentration. Conductimetry is shown to be a very good physicochemical method for analysis of these solutions. The results showed different behaviour for the two surfactants, which has highlighted a change in the structure of their aggregates which led to the assumption of an interaction between the polymers of high mass and different products of the polymerisation (oligomers, products of degradation, monomers etc.). Ultrafiltration experiments coupled with ¹H-NMR and conductivity analysis confirm these assumptions.     

含氚废水水泥固化实验研究

研究用水泥固化处理氚废水,并选择了最佳配方:水与灰的重量比=0.45～0.5,水泥与石膏重量比=5∶1。用IAEA推荐的方法做浸出实验。为了减少水泥固化体中氚的浸出量,实验了几种涂层材料。沥青涂层可将固化体氚的浸出率降低1～2个量级。     

Ionic Strength Effects on Heat-induced Gelation of Myofibrils and Myosin from Fast- and Slow-twitch Rabbit Muscles

The effects of ionic strength on myofibrils and myosin from rabbit fast-twitch Psoas major (PM) and slow-twitch Semimembranosus proprius (SMp) muscles before and after heating were studied by electron microscopy and thermal scanning rheometry. The direct suspension of proteins in low ionic strength (0.2M KCl; pH 6.0) led to very weak gels, whereas a gradual lowering of the ionic strength (by dialysis against 0.2M KCl; pH 6.0) of 0.6M KCl protein solutions induced strand-type networks at low temperature and strong heat-induced gels. As shown by transmission and scanning electron micrographs, in low ionic strength, SMp myosins formed shorter filaments before heating and thinner and shorter structures in heat-induced gels, as well as a lower gel porosity than PM myosins.     

表面稳定模式铁电液晶的电光特性测试

采用一种改进的高分子膜摩擦定向法成功地实现了表面稳定模式铁电液晶的光学双稳态，对比度大于１４０，响应时间达１００微秒。     

High-temperature,high-pressure thermophysical measurements on liquid zinc

Wire-shaped zinc samples were resistively volume heated as part of a fast-capacitor discharge circuit. Time-resolved measurements with submicrosecond resolution of the current through the specimen, the voltage drop across it, and the thermal expansion of the specimen as a function of time allow determination of the enthalpy, electrical resistivity, and density at different temperatures up to superheated liquid states of zinc far above the normal boiling point. High static pressures, up to 3800 bar of the ambient medium water, were used. An estimate of the critical pressure for zinc is given by investigations of the stability of the sample with a framing CCD camera, taking pictures of different samples varying the ambient static pressure. The critical volume and the critical temperature are obtained by means of an extrapolation of measured data at different pressures.Paper presented at the Fourth International Workshop on Subsecond Thermophysics, June 27–29, 1995, Köln, Germany.