Transmitted characteristics for a Gaussian beam passing through a misaligned Fabry-Perot interferometer

After deriving the expression of the intensity of the transmitted beam for a Gaussian beam passing through a misaligned FPI, the influence of the nonparallelism in FPI mirrors alignment on the transmission of a Gaussian beam has been investigated numerically. The results show that the energy profile of the total transmitted beam appears multiple sub-peaks structure; with the increase of the nonparallelism in FPI mirrors alignment, the number of the sub-peaks raises, the peak intensity of the transmitted beam has a declining tendency, and the peak intensity position of the total transmitted beam is shifted.     

Nd扩渗BaTiO_3陶瓷的电性能与XPS研究

采用气相法对钛酸钡陶瓷扩渗Nd元素,经Nd扩渗BaTiO3陶瓷的电性能发生了十分显著的变化。通过正交实验,确定了最佳扩渗条件,当Nd的浓度为2%,扩渗时间为4h,扩渗温度为860℃时,BaTiO3陶瓷的导电性最好,其室温电阻率从4 3×109Ω·m下降为37 45Ω·m,而且随着温度升高,交流电导逐渐增大,导电性更强。Nd扩渗使BaTiO3陶瓷的介电常数增加,而介电损耗降低,BaTiO3陶瓷的介电性能得到了显著改善。经Nd扩渗BaTiO3陶瓷的介电常数随着温度的变化呈明显的PTC效应,其居里温度降低为118 1℃。经XPS测试分析,给出了Nd扩渗BaTiO3陶瓷体系中各元素结合能位置的峰值,并表明Nd扩渗BaTiO3陶瓷中Nd,Ba,Ti都存在变价,因而导致了BaTiO3陶瓷导电性的增强。     

Structures and chromatographic characteristics of capsule-type silica gels coated with hydrophobic polymers in reversed-phase liquid chromatography

Summary Silicone polymer-coated silica gels modified with octadecyl and octyl groups (S/S-C₁₈, S/S-C₈), or “capsule-type silica gels” were developed as packing materials for reversed-phase liquid chromatography. They were obtained by coating the surface of totally porous silica gel with a homogeneous silicone polymer film, and thereafter modifying the coating polymer with octadecyl or octyl groups. Retaining the advantages of silica-based packings, they show strong resistance of alkali-like organic porous polymeric materials.     

氯霉素类兽药的三甲基硅衍生物的质谱特征及其残留测定

氯霉素(chloramphenicol,CAP)是20世纪50年代开发出来的一种广谱抗生素,因其对人体具有严重毒副作用而被禁止在食用动物源产品上使用。甲砜霉素(thiamphenicol,TAP)是人工合成的氯霉素类抗生素,结构与CAP类似,毒性较CAP小,但美国等发达国家也已禁止在食用动物上使用。氟甲砜(氯     

The properties and potential uses of cyclodextrin derivatives

The hydroxyl groups can be selectively substituted to control the solubility and the complex forming selectivity of the modified cyclodextrins (CDs). Among the methylated CDs only two well-defined compounds can be taken into consideration: dimethyl- and dimethyl-CD (DIMEB and TRIMEB). In an aqueous solution of DIMEB the solubility of rather insoluble compounds and drugs like steroids, vitamin D₃, lidocaine and hydrocortisone increases. In some cases their stability and bioavailability are also improved. On the other hand, the hydrolysis rate of carmofur, coumarins etc. is retarded by the methylated cyclodextrins with blocked hydroxyl groups. The drug solubilizing capacity of hydroxypropyl-CD (HPBCD) is in most cases lower than that of DIMEB. The degree of substitution (DS) shows no remarkable effect on the solubilizing properties of HPBCD in the case of indomethacin, Dipiridamole etc., but in the case of Tolnaftate the solubility was enhanced by increasing the DS, other examples are shown.     

阳极改性对单室微生物燃料电池性能的影响

构建了老龄垃圾渗滤液为底物的空气阴极型单室微生物燃料电池,以考察阳极不同改性方式对微生物燃料电池产电性能和对老龄垃圾渗滤液处理效果的影响。结果表明,碳毡阳极经过热处理、浓硝酸、酸性重铬酸钾、混酸的改性后,电池的最大输出功率密度分别提高了104%、241%、51%、181%,COD的去除率变化不大,但氨氮去除率分别增加了22.2%、21.8%、2.3%、47.3%。垃圾渗滤液pH值升高、电导率呈下降趋势。     

Thermoluminescence and optical properties of some dosimetric materials

Thermoluminescence and optical properties of LiF:Mg,Cu,P; BaSO₄:Dy; BaSO₄; Eu and -Al₂O₃:C were investigated as a part of a broader research project on TL mechanisms in various materials. The effects of ionizing radiation on these phosphors are determined in this work by means of thermoluminescence and optical absorption experiments with the aim of identifying new defects formed in these systems and of testing dosimetric characteristics.Dedicated to Prof. Menachem Steinberg on the occasion of his 65th birthday     

Synthesis, Structure, and Chemical Properties of N-Substituted 2(3)-Imino-2,3-dihydrofuran-3(2)-ones. (Review)

Published data on the synthesis, structure, and chemical properties of N-substituted 2(3)-imino-2,3-dihydrofuran-3(2)-ones to 2002 are reviewed     

Thermodynamic and adsorption properties of semiinterpenetrating polymer networks based on polybenzimidazoles and polyaminoimide resin

Thermodynamic characteristics of adsorption of organic compounds on semiinterpenetrating networks based on polybenzimidazoles and polyaminoimide resin with different compositions were studied at small coverages using inverse gas chromatography. The following characteristics were determined: adsorption equilibrium constants (specific retention volumes) of substances of different classes (n-alkanes, aromatic hydrocarbons, ethers, ketones, alcohols, and nitrogen- and halogen-containing compounds), appropriate changes in differential molar internal energy and Helmholtz potential, and changes in standard molar entropy of the sorbates. The contributions of the molecular fragments to the heat of adsorption were calculated. The adsorption properties of the semiinterpenetrating networks based on polybenzimidazoles and polyaminoimide resin differ from those of the starting polymeric materials and their physical mixtures with the similar composition. Unlike graphitized thermal carbon black (nonspecific adsorbent), the network and starting materials manifest the specific properties (electron-donating and electron-accepting). The difference in the thermodynamic characteristics of adsorption on the semiinterpenetrating polymeric networks with different compositions is determined by the size and geometry of interphase regions.     

金属表面分子纳米结构的构筑及性质研究

结合近期研究工作, 简要介绍了在溶液环境下, 利用有机分子在金属表面构筑纳米结构, 利用光化学反应方法调控所得的纳米结构, 利用电化学扫描隧道显微镜对这些结构进行观察, 及利用毛细管隧道结方法测量纳米结构电学性质的相关结果. 并展望了表面纳米结构的构筑、控制和性质研究领域的发展趋势.