氰乙基纤维素溶致性液晶的研究

氰乙基纤维素在二甲基甲酰胺、二甲基乙酰胺、二甲基亚砜、乙腈以及丙酮等溶剂中可以形成溶致性液晶。随浓度增加,溶液从各向同性状态经两相共存态转变成为完全的液晶态。升高温度到T_c,液晶相消失;降低温度到T′_c,液晶相再生成。T_c总大于T′_c。而且,浓度越高,过冷温度△T=T_c—T′_c越小。在各向同性,两相共存或完全的液晶状态,溶液平均折射率和消光度均与浓度呈线性关系。但在两相间相互转变时,即在C_1~*和C_2~*处,n-C和 A-C 曲线上出现转折点。高聚物与溶剂的相互作用参数X_(12)愈小,临界浓度C_1~*愈小。把描述大分子链柔顺性的参数f与X_(12)联系起来,可用 1956年 Flory的理论定性地解释溶剂对高聚物溶致性液晶形成的影响。     

Li^+, Mg^2^+/Cl^-, SO4^2^——H2O四元体系(25℃)的介稳平衡

本文用等温蒸发的方法,研究了 Li~+,Mg~(2+)∥Cl~-,SO_4~(3-)-H_2O 体系(25℃)介稳相平衡,绘制了介稳相图,测定了密度、粘度、折光率、电导率和某些液相点的蒸汽压.该介稳相图由六个结晶区构成,即 LiCl·H_2O、LiCl·MgCl_2·7H_2O、MgCl_2·6H_2O、Li_2SO_4·H_2O、MgSO_4·7H_2O 和 MgSO_4·6H_2O相区.该体系的25℃介稳相图和稳定相图的差异是,新结晶区 MgSO_4·6H_2O 的出现,使 Li_2SO_4·H_2O 相区扩大,其它相区缩小.根据 Pitzer 电解质溶液理论,用单纯形法在 M68000计算机上进行了体系溶解度关系的计算,并获得了计算的溶解度数据,绘制了计算的相图.     

Au和SiO2多壳结构的制备和表征

利用自组装技术和胶体还原化学, 制备出金纳米壳Au@SiO₂以及SiO₂包裹的金纳米壳SiO₂@Au@SiO₂; 去除SiO₂@Au@SiO₂颗粒中的金壳层, 获得含有可移动SiO₂核的空心壳H-SiO₂@M-SiO₂. 结果显示: SiO₂@Au@SiO₂复合颗粒表面光滑, 并保留了金壳的近红外吸收特性; 通过改变复合颗粒外层SiO₂厚度, 可以调节其等离激元共振峰的位置; 王水可以有效地去除SiO₂@Au@SiO₂中的金壳, 相应的等离激元共振峰消失.     

邻苯二甲酸二烯丙酯和甲基丙烯酸甲酯共聚物梯度折射率棒制备过程的研究

<正> 梯度折射率棒是折射率沿径向或轴向连续变化的透明圆棒,具有光自聚焦性能。可用于制作自聚焦型光纤维和自焦聚透镜。用玻璃制得的梯度棒直径和折射率差都很小。近年来,开始研究高分子梯度棒,据估计其直径可望达到100mm,折射率差也可达0.1。本文采用二元掖体扩散共聚法,制得梯度棒,其径向折射率分布接近于抛物线型。     

Densities,Ultrasonic Speeds,Viscosities and Refractive Indices of Binary Mixtures of Benzene with Benzyl Alcohol,Benzonitrile, Benzoyl Chloride and Chlorobenzene at 303.15 K

Densities,ρ, ultrasonic speeds, u, viscosities,η, and refractive indices, n, of pure benzene, benzyl alcohol (BA), benzonitrile (BN), benzoyl chloride (BC), chlorobenzene (CB) and their thirty six binary mixtures, with benzene as common component, were measured at 303.15 K over the entire mole fraction range. From these experimental data the values of deviations in ultrasonic speed, △u, isentropic compressibility, △k_s,excess acoustic impedance, Z^E, deviation in viscosity, Dh, and excess Gibbs free energy of activation of viscous flow, G^*E, and partial molar isentropic compressibility, Kφ,2⁰ of BA, BN, BC and CB in benzene were computed. The variation of these derived functions with composition of the mixtures suggested the increased cohesion (molecular order) in the solution and that interaction (A-B)＞(A-A) or (B-B).Moreover, theoretical prediction of ultrasonic speed, viscosity and refractive index of all the four binary mixtures was made on the basis of empirical and semi-empirical relations by using the experimental values of the pure components. Comparison of theoretical results with the experimental values was made in order to assess the suitability of these relations in reproducing the experimental values of u, η and n. Also, molecular radii of pure liquids and the average molecular radii of binary mixtures were evaluated using the corresponding refractive indices of pure liquids and binary mixtures. The average molecular radii of binary mixtures were found to be additive with respect to mole fraction of the pure component.     

水+3-甲基吡啶+溴化钠三元溶液临界跨接现象

采用折射率法在较宽温度范围内研究了溴化钠、3-甲基吡啶和水的临界质量分数分别为0.240、0.192和0.568体系的临界性质, 发现在近临界点临界指数为0.365, 与Fishe重整化值一致. 有效临界指数随着温度逐渐远离临界点, 从0.365下降到0.20左右, 但当排除了“正规项”的影响后, 展现出向平均场理论值0.5单调跨接的行为.     

Volumetric and Refractive Index Behaviour of α-Amino Acids in Aqueous CTAB at Different Temperatures

Densities （ρ） and refractive indices （nD） of glycine （Gly）, DL-alanine （Ala）, DL-valine （Val） （0.02, 0.04, 0.06, 0.08, and 0.10 mol·L^-1） in 0.005 and 0.008 mol·L^-1 aqueous cetyltrimethylammonium bromide （CTAB） have been measured at 298.15, 303.15, 308.15, and 313.15 K. The density data have been utilized to calculate apparent molar volumes （φv）, partial molar volumes （φv^0）, at infinite dilution and partial molar volumes of transfer φv^0 （tr） of amino acids. The refractive index data have been used to calculate molar refractivity （Rr,） of amino acids in aqueous cetyltrimethylammonium bromide. It has been observed that φv^0 varies linearly with increasing number of carbon atoms in the alkyl chain of amino acids, and hence, was split to get contributions from the zwitterionic end groups （NH3^＋ COO^-） and methylene group （CH2） of the amino acids. The behaviour of these parameters has been used to investigate the solute-solute, solute-solvent interactions and the effect of cetyltrimethylammoniuln cation on these interactions,     

New method to solve electromagnetic parabolic equation

This paper puts forward a new method to solve the electromagnetic parabolic equation （EMPE） by taking the vertically-layered inhomogeneous characteristics of the atmospheric refractive index into account. First, the Fourier transform and the convo- lution theorem are employed, and the second-order partial differential equation, i.e., the EMPE, in the height space is transformed into first-order constant coefficient differential equations in the frequency space. Then, by use of the lower triangular characteristics of the coefficient matrix, the numerical solutions are designed. Through constructing ana- lytical solutions to the EMPE, the feasibility of the new method is validated. Finally, the numerical solutions to the new method are compared with those of the commonly used split-step Fourier algorithm.     

测定透光介质折射率的学生自主实验

以前的《教学大纲》对实验的要求是用统一的器材完成同一个实验,现在的《课程标准》对许多实验并没有规定用什么样的仪器来完成,更谈不上具体的操作步骤,这就给教师的实验教学带来更大的自主性.在测定玻璃的折射率实验中,利用学校现有的资源,笔者给学生提供了各种仪器,在教师的引导下,让学生自主选择、实施,有问题教师再进行指点     

太赫兹波段双频带手征性超表面的设计

提出一种具有巨旋光性和负折射特性的双频带手征性超表面结构,该手征性超表面由中间介质层和双层共轭卍字形周期排列而成;通过研究面电流密度分布,解释了巨旋光性和负折射率产生的原因;研究了手征性超表面单元结构的连续圆金属贴片半径和介质层厚度对该结构旋光性和负折射特性的影响。数值模拟结果表明:该结构在0.1～2 THz频率范围内有4个谐振频点,在谐振频点附近,平均折射率均为负值,实部幅值最大为-3.7;该结构在谐振频点附近显示了巨旋光性以及双频带的左旋圆偏振波和右旋圆偏振波负折射特性,最大偏振旋转角达到了122°,右旋圆偏振波折射率实部幅值可达-12.74。