The Effective Temperature of Surfaces of Liquid Metals and Some Non-Metals

An estimation of decrease of atomic bond energy by raising temperature for surfaces of liquid metals and some non-metals had been made. The calculation values of the derivative du_sdu_b where u_s and u_b, are bond energy of atoms in surface and bulk of a liquid, are significantly above 1 and in limits from 2 to 10. It was supposed that this results from anomalously intensive thermal expansion of surface layers of liquids – the effect which is well known for crystal surfaces. This expansion was explained by the effective temperature of these surfaces which, thus, was found to be by several times above those for bulk of liquids.     

The Electro-Optical Kerr Effect of Optically Active Liquids

The electro-optical Kerr effect of optically active liquids has been studied theoretically, applying the lamellar model of Jones, and experimentally, by measurement of the solution Kerr constant B₁₂ of a series of solutions of d-and dl-camphor in carbon tetrachloride. Equations are presented which allow the intrinsic phase retardation, δ, associated with the Kerr effect to be determined using the Sénarmont method in conjunction with either dc or pulsed electric fields. The method of determining δ, using pulsed electric fields is particularly useful for solutions having an appreciable electrical conductivity. The time-dependent behaviour of a relaxing system, measured using quadratic detection of the optical transient resulting from the application of a pulsed rectangular electric field, is predicted to be essentially unaffected by optical activity over a wide range of δ and optical rotation.     

The Electro-Optical Properties of Doping Polycyclic Aromatic Hydrocarbon Liquids in Twisted Nematic Liquid Crystals

In this paper, doping liquid materials to enhance the electro-optical (EO) properties of twisted nematic liquid crystals (NLCs) was presented. Two polycyclic aromatic hydrocarbon (PAH) liquids, toluene and 1-methylnaphthalene, were chosen as dopants in order to lower the driving voltage and response time of the NLCs. We find that the main reason of this phenomenon is due to a large amount of reduction in the rotational viscosity of PAH liquids doped NLCs. Without the drawbacks of aggregation that the solid nanoparticles could have, the method of doping liquids provides a more reliable choice for applications in various LC display systems.     

Possibilities for In-situ Observation of Basic Deformation Processes and of Other Dynamic Processes

The purposes of this paper are to discuss the possibilities of HVEM in-situ observation for deriving meaningful results on basic deformation processes by illustrating some examples which have been obtained so far and to assess the capabilities of this method to investigate crystal deformation as well as other dynamic processes. First, the experimental procedures developed by our group in Nagoya to study the dynamic behaviour of dislocations are introduced. Research subjects which have been studied effectively by this method so far are illustrated. The lower safety limit of specimen thickness for deriving information typical of bulk materials, the effects of size and free surfaces of a specimen and the effects of electron irradiation etc. are to be discussed to assess the validity of in situ observation of dislocation behaviours. Some prospects on new applications and extensions of in-situ HVEM for physical and materials research are to be presented, including possibilities for in-situ observation of other subjects such as diffusion, environmental effects, interface reaction, chemical reaction, defect formation during growing or processing of semi-conductors, surface treatment and micro fabrication by electron beam etc.     

Microstructure of Polyphenylacetylene and Other Acetylenic Polymers

¹H- and ¹³C-NMR studies carried out on poly(phenylacetylene)s and poly(pentadeutero-phenylacetylene)s prepared with Ziegler and metathesis type catalysts, revealed two different mechanisms which control the microstructure of acetylenic polymers.

For the Ziegler-type catalysts, thermal induced reactions (intramolecular cyclization, aromatization, chain scission and cis-trans isomerization) of the cis-double bonds (isomerization after double bond formation) are responsible for the polymer microstructure. (For a review see: Progr. Polym. Sci., 8, 133 (1982).) Both isomerization "after” double bond formation as well as isomerization “before^” double bond formation are responsible for the microstructure of polymers obtained with metathesis type catalysts. In both cases, the polymer molecular weight is controlled by the intramolecular cyclization of the cis-polymer chain end. Under reaction conditions where isomerization occurs mainly "before double bond formation, “pure” trans polymers having very high molecular weight are obtained (Polym. Prepr., 24 (1), 239 (1983); Polym. Bull., 9, 548 (1983)).

The microstructure of several other acetylenic polymers will be commented on in relation with the polymerization mechanism and with the microstructure of (CH)_x.     

离子液体对硫化镉粒径和光催化性能调控研究

以氯化镉和硫代乙酰胺为原料,分别以水,离子液以及两者的混合液为溶剂,用超声法成功合成了不同粒径的硫化镉纳米粒子.用XRD,SEM,IR以及UV-Vis等手段对所制备样品的晶型、形貌和光学特性进行了表征;以紫外光为光源、甲基橙为目标降解物评价了硫化镉纳米粒子的光催化活性.结果表明,离子液的引入使硫化镉纳米粒子的粒径明显变小,带隙能量变大,光催化性能测试表明,离子液介质中合成的CdS纳米粒子具有更高的光催化活性.离子液体对比实验还表明,三乙烯四胺型离子液体中合成的硫化镉具有更高的光催化活性.     

Characteristic Interaction of Na-H-C60 and C60 with Hydrogen and Rare Gases

Abstract

Rare gases such as He, Ne and Ar are trapped in the lattice of solid C₆₀ and (NaH)₄C₆₀ under conditions of ambient temperature and pressure. The mass analyzed thermal desorption reveals that rare gases are desorbed above 400K and their desorption amounts are in nonstoichiometric level. Ar2p and Ar3s X-ray photoelectron spectra show large chemical shifts. These results suggest that He, Ne and Ar have charge and are in valence state.     

Possibilities of X-Ray Absorption Spectroscopy in the Total External Reflection Geometry for Studying Protein Films on Liquids

Crystallography Reports - XANES spectra of protein films (hemoglobin and alkaline phosphatase) formed on the surface of a liquid subphase in a Langmuir trough have been obtained experimentally. The...     

The Effect of Plasticization on Conductivity and Other Properties of Starch/Chitosan Blend Biopolymer Electrolyte Incorporated with Ammonium Iodide

This work focuses on polymer electrolytes composed of a starch-chitosan blend host, ammonium iodide (NH₄I) and glycerol. Fourier transform infrared (FTIR) analysis confirms the interaction of starch-chitosan-NH₄I-glycerol. The highest room temperature conductivity is (1.28 ± 0.07) × 10^?3 S cm^?1, obtained by a sample containing 30 wt% glycerol. Dielectric studies showed that the electrolytes obeyed non-Debye behavior. The total ionic transference number for the 30 wt% glycerol sample was 0.991, and the conduction mechanism for this sample followed the quantum mechanical tunneling (QMT) model. Linear sweep voltammetry (LSV) showed that this sample was electrochemically stable up to 1.90 V. The highest conducting sample was used in the fabrication of an electrical double layer capacitor (EDLC) cell.     

The Synthesis and Characterization of Thermotropic Liquid Crystal Model Compounds

Recently, the unique morphological classification of the “liquid crystal” state has simultaneously aroused the interest of the industrial and scientific community. With this renewed interest has come a need for better understanding and characterization of the liquid crystal transitions which occur within the many polymeric systems exhibiting this morphological phenomenon. Of the seven newly synthesized thermotropic materials for this study which are p-hydroxybenzoic acid modified compounds, six were of the rod-like geometry typically associated with mesogens. The seventh compound, a derivative of pentaerythritol, was cross-shaped and had a crystalline morphology. All compounds, including the p-hydroxybenzoic acid modified mesogenic precursor, were subjected to various characterization techniques such as proton Nuclear Magnetic Resonance (NMR), infrared spectroscopy (IR), and elemental analysis for structure determination, as well as differential scanning calorimetry (DSC), polarising microscopy equipped with a hot stage, and Fischer-Johns apparatus for thermal analysis.

Results of this study reconfirms previous investigations of similar low molecular oligomers with mesogenic forming ability both in terms of the predictable and of the actual range of the thermotropic and thermodynamic transitions. A different morphological state exists for at least two of the compounds which seemed to exhibit both crystalline and liquid crystalline states. The existence of this morphology created the opportunity for comparison of model compounds of this study with that of polyurethanes.     

软轴型单晶炉提拉系统的振动建模与分析

当软轴型单晶炉提拉系统工作在某一转速附近时,其重锤摆动量会显著增大,严重影响单晶生长质量.为解决此问题,需要建立该系统的数学模型来研究提拉系统的动力学特性.本文在对提拉系统工作原理分析的基础上,应用Lagrange第二类方程建立了考虑该系统面内、面外振动的四自由度非线性振动微分方程.导出了该非线性模型的近似线性模型,对非线性模型响应与线性模型响应做了比较.进一步分析了系统的稳定性,应用Campbell图得到了考虑回转惯性效应后系统的临界转速.通过数值仿真定量说明了减小对中误差和增大阻尼可以减小重锤系统最大摆动幅值.     

石榴石晶体生长过程的生长动力学模型

本文开发了一种基于边界保角变换技术的有限元方法来研究熔体法石榴石晶体生长过程中界面动力学的影响.建立了一个可导致界面上小面形成的动力学模型,该模型可处理界面上粗糙面区域和光滑面区域共存的复杂情况.模型中小面区域的动力学系数与界面上的过冷度及取向角均有关.计算结果显示了小面的形成和界面上各向异性的过冷度分布.     

硅烷热解多晶硅气相沉积反应模型分析与验证

在综述现有硅烷热解反应机理的基础上,针对Ho等人提出的气相和表面反应机理,采用二维边界层反应模型和CHEMKIN软件,对水平单基片CVD反应器进行模拟分析,计算结果与文献报道的实验数据拟合良好;通过改变硅烷进气浓度和进气温度,分析沉积速率的变化和各表面反应的贡献率,得到硅微粉再沉积过程随浓度和温度的变化规律;使用上述机理模型,计算了硅烷流化床对应的操作温度和硅烷浓度条件下的沉积速率,与文献报道测量结果比较,误差在合理范围,表明该机理适用于硅烷流化床化学气相沉积过程的CFD耦合模拟.     

含酯基吡啶类离子液体的晶体结构及酯基链长微变对其性质的影响

基于酯基链长的微小变化,采用两步法设计合成两个含酯基吡啶类离子液体1-乙酸甲酯基-3-甲基吡啶六氟磷酸盐[MeMPy][PF6](记IL1)和1-乙酸乙酯基-3-甲基吡啶六氟磷酸盐[EAMPy][PF6](记IL2).采用溶剂挥发法在混合溶剂体系中获得6.5 mm IL1和8.0 mm IL2大单晶体,酯基链由乙酸甲酯基微变为乙酸乙酯基,其晶体结构及超分子结构的形成具有显著的变化.晶体学数据研究表明,IL1属于三斜晶系,空间群为P1,其晶胞参数为a=0.8754(3) nm,b =0.8780(3) nm,c=1.0551(6) nm,z=2等.IL2属于正交晶系,空间群为P2(1)2(1)2(1),其晶胞参数为a=0.7127(17) nm,b=1.2792(3) nm,c=1.5327(3) nm,z=4等.随着酯基链的增长,分子结构空间位阻发生了变化,IL2中亚甲基和吡啶环上的甲基均参与超分子空间网络形成,改变了晶体堆积的空间点阵和性质.进一步实验验证表明,酯基链较长的IL2熔点较高,热稳定性较差,然而阳离子结构的微小变化对其离子导电活性的影响相对较小.     

溶液对流与温度起伏之间关系的理论模型和实验验证

建立了二维坐标系下溶液对流与形核之间关系的理论物理模型,结果表明:在周期性边界条件下,只要两个坐标轴方向上液体的流动速度不为零,就能产生周期振荡解.将氯化铵晶体溶于水中,加热到过饱和度温度以上,进行自然冷却,在高于过饱和度温度3.7 ℃时,进行搅拌,在1~5 s内,液体内大量形核,出现大量晶体,这与理论模型的计算结果相吻合.     

利用辐射加热炉进行蓝宝石及其它高温氧化物的热物理和光学性能的研究

本文描述了一种特大的实验装置-辐射加热炉,获得了蓝宝石和其它高温氧化物在固相、液相时的光学、热学和物理性能.该装置和相应的技术使得在高于3500K温度下研究这些材料的粘度、熔点、热导率、发射率和吸收系数成为可能,并以此得到了高温下蓝宝石的分子热传导系数,以及不同降温速率下蓝宝石的过冷情况.此外,介绍了一种复合氧化物材料MgO-Al2O3-HfO在宽波段范围内的反射率.本文所给出的数据对于从事晶体和高温陶瓷方面研究的专家学者将很有用处.     

利用水平沉积法制作PS微球二元胶体薄膜及其它复杂结构

本文采用水平沉积方法,制作出各种胶体晶体薄膜.以聚苯乙烯微球为构建单元,制作了多种二元胶体晶体和非单一平面的胶体晶体.为实现太赫兹光子晶体波导,还采用这一方法将线缺陷植入胶体晶体.结果显示通过该方法可以获得很好的有序结构,说明水平沉积方法可以广泛于各种胶体晶体制作.     

High-Temperature Precipitation of Impurities within the Vlasov Model for Solids

Crystallography Reports - It is shown that the Vlasov model for a solid describes the complexing processes when growing real crystals with allowance for the thermal growth conditions. It makes it...     

The Synthesis of Crystals of Chalcogenides of K,Zr, Hf,Hg, and Some Other Elements in Halide Melts under Conditions of Stationary Temperature Gradient

Crystallography Reports - The growth of crystals of metals, alloys, chalcogenides, and pnictides in melts of alkali metal halides under conditions of stationary temperature gradient has been...