共查询到20条相似文献,搜索用时 62 毫秒
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由铁电液晶(FLC)手性近晶C相下螺旋结构的理论近似计算得出FLC一个螺距内平均折射率的表达式,根据表达式可得出一个螺距内的FLC分子作为一个整体可以看成一个向列相液晶分子模型的结论.当FLC沿螺旋轴方向的厚度等于FLC螺距的整数倍时,液晶盒内垂直取向的FLC分子可看作向列相液晶模型组成的集合.ZLI-3654型FLC与5CB型向列相液晶的实验结果验证了上述结论,理论结果和实验结果一致.这一理论可为畸变螺旋FLC和垂直排列畸变螺旋FLC器件的制备以及FLC的应用提供理论指导和更深的认识.
关键词:
铁电液晶
螺距
平均折射率
向列相液晶 相似文献
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设计制作了梳状电极染料掺杂胆甾相液晶激光器件,研究了外加电压下的激光辐射谱。器件的下基板ITO电极刻蚀成梳状条形电极,电极宽度约2 mm,相邻电极间距分别约为1,3,5 mm。上基板无ITO电极。上下基板取向膜平行摩擦取向处理,使胆甾相液晶平面态排列。以532 nm的Nd∶YAG激光器作为泵浦光源,测量器件激光辐射谱。改变外加电压0~100 V,3个区域均出现了多模输出。在1 mm电极间距区域,可获得633.65~621.52 nm(12 nm)和683.15~664.35 nm(18 nm)的可调谐波长范围;在电极间距3,5 mm区域,辐射激光波长变化微小。在外加电压作用下,液晶分子均匀的螺旋周期排列受到扰动,液晶分子层螺旋轴倾斜,各个液晶畴的螺旋轴取向不一致,使有效螺距值缩短并有所浮动,引起出射激光波长蓝移和多模输出。利用光子态密度理论数值模拟了激光辐射谱。当有效螺距为倾斜角的函数时,随着倾斜角增大出射激光波长蓝移。 相似文献
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提出一种研究螺旋液晶光学特性的数学处理方法.螺旋型液晶可当作N层双折射材料晶片叠合而成,而相邻晶片的光轴依次旋转一个小角度.在光学转换矩阵中引入复数来研究螺旋型液晶光学性能,给出了相关的数学处理方法.研究了线性偏振光在螺旋液晶中的传播特性,并给出了光经过螺旋液晶后电场强度的矩阵表达式.研究发现,如果入射光波长等于螺旋液晶螺距,线偏振光经过右螺旋液晶后是左旋圆偏振光.理论上分析了螺旋液晶对可见光选择性反射机理. 相似文献
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为了有效研究液晶环境对金属纳米结构表面等离子体的调制作用,基于时域有限差分方法,对液晶环境下金纳米柱结构进行了建模,上下边界采用完全吸收边界条件,四周为周期边界条件.数值模拟了液晶厚度、倾角、光栅距离以及周期结构等参数对金纳米柱的消光特性的调制作用.分析结果表明:随着液晶光轴角度增加,谐振波长出现红移现象,且调制范围为40nm;光栅距离越大,金纳米柱之间的相互作用越弱,谐振波长越小;增加周期长度,谐振波长红移,且随着周期长度增加,次峰作用越明显.利用液晶光学性质可调节金属纳米结构的表面等离子体特性,结果对液晶环境中表面等离子体结构在新的光子器件等方面的研究提供了理论依据. 相似文献
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阐述一种理论模型,讨论共面转换(IPS)模式下横向电场对平面织构胆甾相液晶螺距及扭曲角的影响.利用琼斯矩阵法计算了光正入射情况下未加电场时胆甾相液晶的反射谱.在上述模型基础上,计算了施加电场后胆甾相液晶的反射峰值波长以及反射带宽随场强的变化关系.探讨了忽略锚定与强锚定两种边界条件下横向电场对平面织构胆甾相液晶螺距及反射特性的影响.所得结论在理论上证实:共面转换模式下电场可以调谐胆甾相液晶的反射光颜色,从而为基于电控螺距原理的胆甾相液晶反射式彩色显示方案提供了理论上的依据.
关键词:
胆甾相液晶
电控螺距
共面转换
琼斯矩阵法 相似文献
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本文通过理论和实验对液晶 5CB在剪切和电场耦合作用下流变行为进行了研究. 采用液晶连续理论, 建立了包括界面锚定能, 弹性自由能, 介电自由能和流动能在内的系统 Gibbs自由能公式, 通过最小化系统自由能的方法求解液晶在剪切和电场耦合作用下的取向分布及其黏度变化, 从分子基础模型上揭示了液晶在耦合作用下的流变行为、微观机理及其影响规律, 并通过流变测试对此进行验证. 对比分析了理论和试验结果的误差和原因, 发现界面锚定效应对于液晶分子的取向和黏度具有重要影响. 理论和试验结果均表明, 液晶在电场作用下具有明显的电黏效应, 表现出非牛顿流变行为, 其黏度值由剪切和电场的竞争和耦合作用共同决定. 在外电场作用下液晶的黏度可以增加到初始值的 4倍左右, 液晶这种其自身黏度可随着外场 (例如运动速度) 改变的特性在一定的条件下可以自适应地满足不同工况对黏度的要求, 这对实现智能摩擦润滑具有重要的意义.
关键词:
液晶
流变行为
电黏效应
耦合作用 相似文献
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Electron-diffraction measurements for heavy and light water at 5°C are presented and analysed in terms of atom-atom pair-correlation functions and molecular correlation functions. 相似文献
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Equilibrium wetting of ethanol, a volatile liquid, onto chemically patterned nanostripes has been investigated using noncontact atomic force microscopy (AFM). The chemical patterns, generated by a conducting AFM tip, are composed of COOH terminated "wetting" regions and CH3 terminated "nonwetting" regions. Controlled amounts of ethanol, from the vapor phase, condense on the COOH stripes and their shape is imaged in situ versus their width (70 < w < 300 nm). The measured profile shapes at saturation and their w(1/2) height dependence are well described by density functional theory with dispersive, nonretarded potentials. 相似文献
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The term “liquid crystal” signifies a state of aggregation that is intermediate between the crystalline solid and the isotropic liquid. A substance in this state is strongly anisotropic in some of its properties and yet exhibits a certain degree of fluidity, which in some cases may be comparable to that of an ordinary liquid. A large number of organic compounds are now known to form liquid crystals. An essential requirement for mesomorphism to occur is that the molecules must be highly geometrically anisotropic. The transition to the intermediate state may be brought about by purely thermal processes (thermotropic mesomorphism) o r by the action of solvents (lyotropic mesomorphism). 相似文献
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N. G. Samoilenko B. L. Korsunskiy E. N. Shatunova V. A. Bostandgiyan L. V. Kustova 《Russian Journal of Physical Chemistry B, Focus on Physics》2018,12(5):875-882
In this paper, the regularities of a thermal explosion of a heterogeneous system consisting of two immiscible liquids have been studied. Each phase is a solution of A and B reagents. Reagent B is extracted into a solution of reagent A, where the bimolecular exothermic reaction A + B → Products takes place. It has been shown that an exothermic reaction (combustion regime) continues to proceed in the system at high mass-exchange rates between phases after a thermal explosion. As a result, the maximal temperature may significantly exceed the temperature of the thermal explosion. The critical value of the Semenov parameter decreases with an increase in the mass-exchange rate between phases. In the limited range of values of the distribution coefficient of reagent B between phases, the increase of this coefficient is also accompanied by a decrease in the critical value of the Semenov parameter. The concentration of reagent B in the initial phase decreases monotonically due to its extraction into another phase. However, the equilibrium of the extraction of reagent B can shift, due to the temperature dependence of the distribution coefficient during the reaction. Thus, the time dependence of the concentration of reagent B on may be more complex and can pass through a minimum. 相似文献
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E. Kuphal 《Applied Physics A: Materials Science & Processing》1991,52(6):380-409
This paper presents a comprehensive review of the method of liquid phase epitaxy (LPE) of semiconductors. In Sect. 1 the physical principles including diffusion-limited growth and solid-liquid phase diagrams are treated in detail. In Sect. 2 technological aspects and various kind of growth systems including industrial versions are described. Section 3 summarizes the relevant properties of LPE grown layers. Section 4 contains the application of LPE to the material system InP/InGaAs/InGaAsP as a model system. In Sect. 5 the advantages and weaknesses of LPE with respect to device applications in comparison with competing methods are discussed, and finally we attempt to predict the future direction of LPE. 相似文献
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液晶显示器(简称LCD)是当今及可预见的将来最重要的信息显示媒介之一.它的发展经历了三代:第一代用于计算器、手表;第二代用于电子翻译机、游戏机、家电设备、测试仪器;第三代用于高级信息社会的各种办公室自动化设备、新型信息传递设备,如笔记本电脑、文字处理机、手机、便携式彩色电视机等. 相似文献
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文章从燃烧热测定的方法原理,实验操作,数据处理和应用的角度,探讨了液体样品燃烧热测定方法.取一定量的标准试样,置于氧弹中,向氧弹中充入过量的氧气,再将氧弹置于一定量的水中,让试样在氧弹中燃烧,释放的热量被水吸收,准确测定水的升温值,在一定温度下,吸收热量的水以及水中各个器件所构成的量热体系的热容量是一个常数,然后将样品与已知热值且不易挥化的液体混合后一并装入封闭的聚乙烯燃烧杯中,利用得到的仪器热容量,按相同的实验操作方法,利用自编的数据处理系统计算出液体样品的燃烧热.此法准确、简便、实用,用于日常检测工作. 相似文献