立方面心C60晶体晶格振动的研究

采用C60分子之间相互作用势的Kihra形式,研究了立方面心C60晶体的晶格振动问题,得到了质心振动沿[111]、[110]及[100]方向的声子散射圆频率分布曲线及C60晶格振动频率的态密度分布.采用所得到的C60晶格振动频率的态密度分布,计算了晶体C60在298 K时的等压热容,所得数值与实验值相符.     

Growth and characterization of a new metal-organic nonlinear optical bis (thiourea) cadmium zinc chloride single crystals

A new semiorganic nonlinear optical bis (thiourea) cadmium zinc chloride (BTCZC) crystal has been synthesized. BTCZC single crystals were grown from aqueous solution by slow evaporation technique. The solubility of BTCZC has been determined for various temperatures. Single crystal X-ray diffraction (XRD) study has been carried out to identify the lattice parameters. Fourier transform infrared (FTIR) studies confirm the various functional groups present in the grown crystal. The transmission and absorption spectra of this crystal show that the lower cut off wavelength lies at 260nm. The thermal analyses confirmed that the crystal is stable upto 201 degrees C. The nonlinear optical (NLO) property of the grown crystal has been confirmed by Kurtz-powder second harmonic generation (SHG) test.     

铌酸锂单晶光纤包层研究

通过镁离子内扩散铌酸锂单晶光纤，以改变晶纤表层的折射率，首次在国内实现了沿不同轴向生长、不同掺杂的铌酸锂单晶光纤的芯－包层波导结构。通过匹配扩散温度、扩散时间、ＭｇＯ膜厚等扩散参数及选择合适的晶纤直径，实现了晶纤具有阶跃和抛物折射率分布的包层，并对包层晶纤的模式特性进行了观察，得到低次模传输。     

Synthesis and functional properties of green fluorescent poly(methylmethacrylate) for use in liquid crystal systems

The copolymerization of six 4-aminosubstituted-1,8-naphthalimide dyes comprising an allylic polymerizable group with methylmethacrylate has been investigated. The utility of the copolymers prepared as fluorescent component in polymer/liquid crystal systems has been examined. The photophysical and photochemical properties of the systems monomeric dye/liquid crystal and copolymer/liquid crystal have been also discussed. It has been shown that in a liquid crystal mixture 1,8-naphthalimide dyes and respective copolymer/liquid crystals have yellow–green fluorescent color with good photostability. Copyright © 2003 John Wiley & Sons, Ltd.     

Crystal and molecular structures of pentazoline hydrochloride dihydrate

The crystal structure of pentazoline hydrochloride dihydrate has been established by x-ray structural analysis. A comparative analysis has been made of the crystal structures of the dihydrates of the hydrochlorides of pentazoline and of deoxypeganine.     

Growth of <201> 8-hydroxyquinoline organic crystal by Czochralski method and its characterizations

In this study, 8-Hydroxyquinoline (8HQ) single crystal has been successfully grown by Czochralski method. The unit cell parameters of 8HQ single crystal were confirmed by single crystal X-ray diffraction analysis. The crystalline perfection of grown crystal has been analyzed by high-resolution X-ray diffractometry. Fourier transform infrared spectral studies have been performed to identify the functional groups. The UV?CVis-NIR studies show that the grown 8HQ crystal??s cutoff wavelength is around 390?nm. The thermal property of the grown crystal was studied by thermogravimetric and differential thermal analysis. The laser damage threshold value of the grown crystal was measured at multiple-shot mode using Nd:YAG laser. The dielectric measurements were carried out to determine the dielectric behavior for the crystal. The SHG efficiency of 8HQ is 0.8 times that of KDP.     

有关那格列奈晶型的研究

Ｎ (反式 4 异丙基环己基 1 甲酰基 ) Ｄ 苯丙氨酸 ,药品名那格列奈 ,作为治疗二型糖尿病的药物1 999年在日本上市 ,药效与其晶体存在的型态密切相关。Ｂ型晶不稳定 ,Ｈ型晶对研磨的稳定性较高 ,比Ｂ型晶更适合于制药[1 ] 。此外 ,我们发现Ｂ型或Ｈ型晶在一定条件下可转化为熔点较高的第三种样品———ＶＨ型晶。测定了三种那格列奈样品的熔点 ,用示差扫描量热 (ＤＳＣ)、热重差热 (ＴＧＡ ＤＴＡ )、红外 (ＩＲ)及Ｘ 射线粉末衍射 (ＸＲＤ)等对它们进行了表征。那格列奈的分子结构如下图所示 :1　实验部分1 1　制备Ｂ晶熔点 1 2 8～ 1 3…     

Non‐linear electromechanical transformations and amplification acoustical signal in ferroelectric liquid crystals

Resonance systems with ferroelectric liquid crystal have been investigated, and the parametrisation of an oscillation system with resonance properties depending on ferroelectric liquid crystal properties has been investigated. The parametric amplifier of mechanical oscillations has been obtained for the first time. The results have been analysed using different existing theories of SmC* liquid crystal dynamics.     

Structure and properties of a bimolecular crystal (2CL-20 + MNO)

A novel bimolecular crystal (BMC) of CL-20 and N,N'-dimethyl-N,N'-dinitrooxamide (MNO) has been prepared. Molecular and crystal structures have been determined. Thermal stability has been studied with DSC technique.     

Spectroscopic studies on the influence of 10 mol% of glycine on nonlinear optical crystal L-valinium picrate

Nonlinear optics is a fascinating field, which plays a vital role in the emerging field of photonics and optoelectronics. A new nonlinear optical crystal of glycine mixed l-valine picrate (GVP) have been grown from saturated aqueous solution by slow evaporation method at a temperature of 36 °C using a constant temperature bath of accuracy of ±0.01 °C. The synthesized organic optical material has been purified by repeated recrystallization. Single crystal X-ray diffraction analysis has been made to determine the cell parameters and it confirms the crystal lattice to be orthorhombic. UV–vis-NIR spectrum have recorded for GVP crystals in the range from 190 nm to 1100 nm and it is found that the crystal has cut-off at 450 nm. Fourier transform infrared transmission has confirmed the presence of the functional group present in the title compound. The spectrum has been recorded by KBr pellet technique. The ¹H and ¹³C NMR spectra have been recorded to elucidate the molecular structure of GVP crystals. The second harmonic generation (SHG) of the grown crystal have been confirmed by Kurtz–Perry method using Nd:YAG laser as source.     

Inward-growing self-assembly of colloidal crystal films on horizontal substrates

Colloidal crystal films have been fabricated on solid substrates with a horizontal deposition method. Scanning electron microscope images showed that the colloidal crystal films exhibit ordered face-centered cubic structures in large domains. Optical measurements demonstrated the presence of photonic band gap along the crystallographic [111] direction. The fabrication method described in this paper allows one to rapidly fabricate colloidal crystal films of different thicknesses, which can be controlled by varying colloidal suspension concentration or volume. In addition, the method also works well for growing colloidal crystal films on a hydrophilic solid substrate with a rough surface. Furthermore, the fabrication of colloidal crystal heterostructures has been demonstrated. An inward-growing mechanism responsible for self-assembly of colloidal spheres on horizontal substrates has been proposed to interpret the observed experimental results.     

一种聚乙烯晶鬚的结构模型

以前,不少人认为高聚物的结晶形态和结晶过程与低分子化合物比较起来有着原则性的差别.但是从1957年Till,Keller和Fischer分别独立地从聚乙烯的二甲苯稀溶液中培育出单晶体以来,大量的研究工作都表明尽管高聚物有着许多不同于低分子     

A small-angle X-ray scattering study of nanoparticle assembly in an aligned nematic liquid crystal

The assembly of colloidal particles in a nematic liquid crystal has been investigated using small-angle X-ray scattering. The structure and orientation of nanoparticle assemblies in bulk samples of aligned nematic liquid crystal have been determined. The method offers some advantages over optical microscopy, which is usually restricted to investigations of thin cells and micron-sized particles. The scattering from chains of particles has been calculated, and comparison with experimental results has shown that suspensions of 48 and 105 nm diameter silica nanoparticles formed highly ordered structures perpendicular to the liquid crystal director, consistent with quadrupolar defect-induced assembly.     

Refinement of the crystal structure of (RS)-carnitine hydrochloride

A single crystal of (RS)-carnitine hydrochloride has been obtained, and its crystal structure has been refined by an x-ray structural experiment.Tashkent Pharmaceutical Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 842–844, November–December, 1991.     

Molecular and crystal structures of 6-substituted 4-phenylquinazoline 3-oxides and 2,2,6-trimethyl-4-phenyl-1,2-dihydroquinazoline

Single crystal X-ray diffraction (XRD) has been employed for the determination of crystal and molecular structures of three 6-substituted 4-phenylquinazoline 3-oxides. Characteristic features of the structures have been revealed, intermolecular interactions have been considered.     

Growth of polyethylene single crystals from the melt: Morphology

Three-dimensional shape of polyethylene single crystals grown from the melt has been studied. Two distinct types of lateral habit have been obtained: lenticular shape (type A) and truncated lozenge (type B) in the range of regime I and II. Electron microscopy has revealed chair-like shape of type B crystal and reconfirmed the planar shape of type A crystal. In the type B crystal, spiral growth has occurred frequently in the {110} sectors and the sense of the handedness of spiral terraces has been maintained. It has been, suggested that the frequens occurrence of spiral growth is responsible for a morphological change (axialite-spherulite) accompanying the regime I–II transition. The origin of the chair-like crystals has been discussed and, a possible mechanism has been suggested for the formation of spiral terraces; the mechanism is based on a distortion caused by the three-dimensional shape of chair-like crystals. It has been found that the chair-like crystals are curved in the opposite way to S-shaped lamellae observed by Bassett and Hodge in banded spherulites. In fact, the present work has led to the recognition of further classes of crystal with curving cross-sections and of distinctions between them. In final analysis, a unifying thread has been identified between lateral habits, growth kinetics and three-dimensional shape of lamellae, in turn, leading to some rationalization of multilayer developments including twisting in banded spherulites, the latter based on existing suggestions in the literature.     

在线性壳聚糖膜内原位还原制备银纳米粒子及银单晶体

采用光还原方法，在线性壳聚糖膜内原位还原获得球形银粒子(粒径10～30 nm)和外观呈三角形、六边形的银单晶体(边长200～2000 nm)；采用电化学方法，在壳聚糖膜内制备了球形银纳米粒子，粒径为5～8 nm.用透射电子显微镜(TEM)、扫描电子显微镜(SEM)、红外光谱(IR)和X射线衍射(XRD)等测试技术对壳聚糖/银复合物进行了表征，对光还原过程中银晶体结构由多晶到单晶的转变原因进行了初步的分析和探讨.     

基于压电晶体传感器阵列技术的智能分析仪

自行设计并组装了使多道石英晶体传感器同时起振的高稳定度的振荡电路及其智能分析仪,同时采用准确、简单的计算方式,用单片机系统进行控制,实现了对多道反应的同步监测和显示。该分析仪弥补了单道检测的缺点,操作简单、性能稳定、成本较低,具有广泛的应用前景。     

Optical rotatory dispersion of rare earth crystal

The ORD spectrum of optically active single crystal of praseodymium oxydiacetate has been studied in the visible range at 77 K. The results have been compared with those obtained in the cases of transition metal complexes and other RE complexes with optically active ligands, and correlated with the site symmetry of the RE ion in the crystal. The optical activity has been related to the magnetic dipole strengths of the transitions.     

主链含间位联结的聚芳醚酮的形态结构

选取分子主链中含有间位结构的聚芳醚酮低聚物为研究对象,利用TEM技术,发现这类低聚物晶体中存在一种新的四角叶片状单晶,此单晶的四角对角线夹角为101.9°,与从晶胞参数计算所得的102.6°一致,从而直观地证明这类含间位结构聚芳醚酮的晶胞按(110)面生长,球晶按b轴方向生长.