LiIO_3-RbIO_3赝二元系相图的研究

一、引 言碘酸盐是许多探索新材料的工作者感兴趣的材料,尤其是碘酸锂晶体的生长、结构、相变、性能等,在国内外都做了大量的工作[1-5],证明它具有良好的非线性光学性质和压电性质,已应用于实际.根据IO3-基团具有未成键的电子对,可以预言,其它碘酸盐也容易形成不具对称中心的结构,可能具有非线性光学及其它例如压电、热电等性能.由这些碘酸盐形成的复盐,其结构及性能如何,则是使人更感兴趣的问题. 碘酸理的结构及其相变见文献[1].碘酸铷的结构见文献[6],没有发现相变.两者的复盐有一化合物[7].当我们进行这项工作时,尚未见其它有关这方面的…     

Mg(IO_3)_2-LiIO_3-HIO_3赝三元系的相关系

一、引 言 碘酸盐晶体由于存在着未成键的电子对,通常不具有对称中心,因而在电光和非线性光学效应方面具有广泛应用的可能性.同时,大部分碘酸盐晶体的空间堆积系数较低,约为50%左右,这就为离子在晶体中运动提供了可能性.所以,碘酸盐晶体作为快离子电导材料也是十分值得探讨的.     

天然丝光沸石对进入其孔道的Sn^2＋的氧化作用

以穆斯堡尔谱为手段，对与二价锡盐进行离子交换的天然丝光沸石以及交换前后的盐溶液烘干样品进行了研究，分析了锡离子的价态。发现天然丝光沸石对进 入其孔道内的Ｓｎ＾２＋具有氧化作用。     

晶体电光和非线性光学效应的离子基团理论(Ⅱ) 利用(IO_3)~(-1)离子基团的分子轨道计算α-LiIO_3晶体的倍频系数

本文对碘酸盐晶体的倍频效应提出了一个(IO_3)~(-1)离子基团模型,并用(IO_3)~(-1)离子基团的分子轨道计算了α-LiIO_3的倍频系数,计算值和实验值符合得很好。由此得出以下结论:碘酸盐晶体的倍频效应主要由(IO_3)~(-1)离子基团和它的共价键轨道所决定。而在(IO_3)~(-1)离子基团中,对倍频效应作出主要贡献的是碘的孤对电子轨道和氧的|2σ>,|2P_y>轨道。     

一种新型锂离子电池聚合物电解质的光谱学研究

本文主要利用Raman光谱对由丙烯碳酸酯(PC)/聚丙烯腈(PAN)/双三氟甲基碘酸酰亚胺锂(LiTFSI)组成的锂离子电池聚合物电解质进行了研究,通过研究发现:Li+离子与PC的缔合和PC对TFSI-阴离子结构的影响导致了Li+-PC-TFSI-离子团的生成。而在所有的PC分子和盐发生缔合之前,PAN却不能溶到PC中。一旦PAN开始溶于PC,电解质内与PC相关的微观结构将不再随盐的浓度的增加而改变。但Li+离子与PAN之间的作用却显得异常激烈。     

α—碘酸锂晶体的空间生长

文章报道了三次α－碘酸锂晶体空间生长实验．该实验是在我国返回式科学技术探测卫星上完成的．为研究空间微重力环境对于晶体生长和物性的影响，应用Ｘ射线衍射、Ｘ射线形貌、Ｘ射线荧光分析、光学透过率和介电测量等技术，对在微重力和常重力条件下生长的晶体结构、完整性、杂质分布以及介电常数等参数进行了研究．研究结果表明：微重力条件下，晶体中β－碘酸锂的含量比地面低；微重力对α－碘酸锂的晶体形态和结构没有影响；微重力条件下生长的晶体的完美性优于地面晶体；微重力环境使碘酸锂晶体的介电常数增高     

晶体电光和非线性光学效应的离子基团理论(Ⅱ)——利用(IO3)-1离子基团的分子轨道计算α-LiIO3晶体的倍频系数

本文对碘酸盐晶体的倍频效应提出了一个(IO₃)^-1离子基团模型,并用(IO₃)^-1离子基团的分子轨道计算了α-LiIO₃的倍频系数,计算值和实验值符合得很好。由此得出以下结论:碘酸盐晶体的倍频效应主要由(IO₃)^-1离子基团和它的共价键轨道所决定。而在(IO₃)^-1离子基团中,对倍频效应作出主要贡献的是碘的孤对电子轨道和氧的|2σ>,|2P_y>轨道。     

Ce(Ⅳ)和Ce(Ⅲ)化合物系列的X射线光电子能谱研究

用XPS研究了标称四价铈盐系列:硫酸铈铵、硫酸铈、二苯基羟乙酸铈、碘酸铈、过氧化铈、二氧化铈以及三价铈盐系列:草酸亚铈、硫酸亚铈、二苯基羟乙酸亚铈、碘酸亚铈和氯化亚铈.结果表明,上述标称四价铈盐都属于混合价化合物,其Ce3d电子能谱呈现Ce⁴⁺和Ce³⁺的二组谱线结构的混合.在真空中加热后CeO₂的Ols电子能谱有两个氧峰,这说明 Ce(4f⁰)O(2p^π)←→Ce(4f¹)O(2p^n-1) 类型价态波动的可能性较大.三价铈盐的3d谱线的低结合能端约3.5—4eV处则存在摔落伴峰.     

通过化学修饰提高由荧光素构成的二进制计算器的安全性

设计并合成了荧光素酰腙类衍生物对羟基苯基荧光素酰腙(FHP),通过对荧光素的化学修饰,并采用酸碱以及二价铜离子为输入,实现了对由荧光素构成的二进制计算器加密的逻辑功能。该逻辑加密功能的实现是基于荧光素酰腙类衍生物对二价铜离子的特异性响应:在碱性环境中,二价铜离子催化FHP完全分解并释放出具有二进制计算器逻辑功能的荧光素分子;在酸性环境中,二价铜离子催化FHP部分分解并与二价铜离子配位形成稳定的二价铜离子配合物,该配合物既不能还原形成原化合物,也不能在碱性环境中释放出荧光素分子,导致该逻辑器件的逻辑功能被彻底破坏。基于该自毁装置的存在,使得该逻辑加密器件的安全性进一步提高。     

Theoretical Calculations of Transition Probabilities and Oscillator Strengths for Sc(III) and Y(III)

利用最弱受约束电子势模型理论计算了二价钪离子和二价钇离子的能级间跃迁几率和振子强度的数值. 二价钪离子的计算结果与美国国家标准技术研究院(NIST)所给出的可接受值吻合良好. 二价钇离子的计算结果也与现有的其他理论方法的计算结果十分接近.     

Interrelation of the macrostructure and microstructure with the nonlinear optical properties of iodate and titanate crystals

Noncentrosymmetric crystals of iodates and titanates have been systematized, and the principles of the design of new nonlinear optical materials by means of revealing empirical composition-structure-property relationships have been considered. It is demonstrated that, in the diagram of chemical bond lengths, noncentrosymmetric crystals of simple and binary iodates and titanates are located within the rosette formed by three partially intersecting ellipses. The empirical dependences of the nonlinear optical susceptibility χ⁽²⁾ of the crystal on the length of the shortest metal-oxygen chemical bond L are established for iodates and titanates. These dependences exhibit maxima at L = 177 and 180 pm for iodates and L = 177 and 188 pm for titanates.     

碱金属碘酸盐赝二元系固溶体的研究

碱金属碘酸盐形成的二十一个赝二元系中,六个体系为机械混合物,九个体系是形成化合物的(其中三个是离子化合物),其余六个体系形成连续固溶体。本文对KIO₃-NH₄IO₃,RbIO₃-NH₄IO₄等赝二元系形成的连续固溶体进行了研究。NH₄IO₃中加入KIO₃或RbIO₃时,随加入量增加,NH< 关键词：     

Changing emission of divalent samarium doped into barium octoborate as a function of firing time

Barium octoborate has been synthesized by air firing of co-precipitated borates with additional boric acid. During the firing process, samarium ions doped into the matrix are reduced to the divalent state. Two different divalent samarium emission spectra have been observed from the material as a function of the firing history, even though the structure, as identified by powder X-ray diffraction remained consistent. A minor barium pentaborate impurity, in conjunction with significant thermal variability in the strength of the divalent samarium emission generated by the different sites in the two borate materials, appears to give rise to this phenomenon.     

Growth and optical properties of BiI3 and PbI2 microcrystals

A study has been made of low-temperature absorption and luminescence spectra of bismuth iodate microcrystals in various hosts (layered cadmium iodate, microporous glasses and polymers), as well as of the spectra of mesoscopic domains formed in bulk bismuth iodate by mechanical strains. The structure of the spectra and the quantum shifts of the exciton levels yielded information on the dimensions and size dispersion of the microcrystals and domains, as well as on the effect of microcrystal size on the Stokes losses. The quantum exciton-line shifts in microcrystalline lead-iodate films grown in pores of the glass host have been used to calculate the film thicknesses. A photoinduced change in the mechanism of radiative recombination was observed in PbI₂ microcrystals. The spectrum of resonant Raman scattering in lead iodate microcrystals consists of broad bands corresponding to the branches of optical phonons undergoing strong angular dispersion. Fiz. Tverd. Tela (St. Petersburg) 40, 1724–1730 (September 1998)     

Optical spectroscopy of conducting Schiff-base polymer films

Polymer samples of complexes of divalent copper with the H₂msalpn-1,3 ligand have been studied by optical spectroscopy. The optical density spectra of metal-polymer films have been analyzed taking into account the influence of preliminary thermal treatment. The spectral dependences of the absorption coefficient and optical band gap are determined for different experimental conditions.     

Heat capacity and thermal conductivity of Fe x Mn1 − x S single crystals

This paper reports on the results of investigations of the thermal properties and thermal conductivity of single crystals of homogeneous solid solutions Fe _x Mn_{1 ? x} S with a cubic NaCl structure, which have been prepared by the cation substitution for divalent manganese ions in manganese monosulfide. It has been revealed that the heat capacity and thermal conductivity exhibit anomalies in the range of the magnetic transition. The cation substitution is accompanied by an increase in the phase transition temperature.     

Optical system aberration effect on the second harmonic generation

The results of observation of the aberration effect representation by the focusing optical system in the angular structure of the frequency-transformed radiation are presented. The experiments have been performed on lithium iodate crystals.     

Morphology and optical spectra of metal iodate microcrystals in porous matrices

Microcrystals of iodates of mercury, lead, thallium, and bismuth were grown in pores of glass and polymer matrices from solutions or through sublimation in vacuum. Images of these microcrystals embedded in matrices were obtained with an electron microscope. Exciton absorption and luminescence spectra of the microcrystals revealed a strong difference in the temperature regions of stability of the various structural modfications between bulk crystals and microcrystals of some iodates. The absorption and luminescence spectra are broadened inhomogeneously because of considerable size dispersion of the microcrystals and exhibit quantum confinement effects. The exciton emission spectra show that exciton interaction in microcrystals becomes significant at very low optical pumping levels because of efficient excitation transfer from the matrix.     

晶体和基团倍频系数间的普遍变换公式

本文使用倍频系数的不可约张量表示法,得到了离子基团的微观倍频系数与晶体宏观倍频系数间的一般变换公式,从而为晶体中不同取向的基因对宏观倍频系数的贡献提供了普遍的计算公式。应用这一计算方法可方便地计算各种碘酸盐的倍频系数,结果相当满意。本文对于探索新型倍频材料,提供了明确的空间结构条件。 关键词：     

Application potential of paratellurite and iodic acid crystals for acousto-optics in the Terahertz range

The possibility of applying paratellurite, iodic acid, and lithium iodate crystals in acousto-optics in the THz range has been investigated. The transparency windows of these crystals and their refractive indices in the THz range have been determined. The acousto-optic figures of merit of these materials are calculated for different acousto-optic interaction geometries.