选择性远程DEPT~(13)C NMR新技术用于新阔叶千里光碱氮氧化合物的结构测定和谱峰归属研究

从湖北蟹甲草根茎中分得一个新的生物碱,选择性远程DEPT~(13)C NMR新技术用于识别NMR信号归属和连接被季碳及杂原子分割的质子自旋系统,确定其结构为新阔叶千里光碱的氮氧化物,如(1)所示。     

A Convenient Method for the Stereoselective Synthesis of 7αHydroxycholesterol

7-Hydroxyderivativesofcholesteroldisplayawidevarietyofbiologicalactivities'-',mostofwhicharerelatedtothephysiologicalcontrolofcholesterolbiosynthesisandantitumoractivity.Inearlyreports',the7-hydroxycholesterolswerepreparedbythesequenceofacetylation,allylicchromicoxidation,andhydridereduction.Generally,theproductisamixtureof7a-and76-epimerswhichisdifficulttobeseparated.V.Kumaretal5improvedthisprocedurebyusingstereospecificreducingreagentsinsteadofthesimplehydride.7a-and7o-epimerscouldbeobtained…     

Sr1-xLaxTiO3的高温高压合成及XPS研究

 利用高温高压方法合成了有稀土元素La掺杂的钙钛矿氧化物Sr_1-xLa_xTiO₃。XRD测试表明，在x≤0.5时，样品基本为单相，呈立方相；晶胞体积随x的增加而增加，在x=0.4时开始减小。XPS测量发现，样品中存在Ti离子的变价。讨论了Ti离子价态的变化对晶格参数的影响。     

Conflict resolution in fuzzy environment

Conflict resolution methodology is discussed with fuzzified Pareto frontier. Four solution concepts, namely, the Nash solution, the generalized Nash solution, the Kalai-Smorodinsky concept, and a solution method based on a special bargaining process are examined. The solutions are also fuzzy, the corresponding payoff values are fuzzy numbers, the membership functions of which are determined. Three particular cases are considered in the paper. Linear, quadratic, and general nonlinear Pareto frontiers with known shape are examined.     

Large area bolometers for millimeter-wave power calibration

An accurate monolithic power meter has been developed for millimeter-wave applications. The detector is a large-area Bismuth bolometer, integrated on a fused-Quartz substrate. It simply measures the temperature change caused by the absorption of millimeter-wave radiation. The power meter is simple to fabricate, inexpensive, and can be easily calibrated using a low-frequency network. The measured responsivity for a 50 bolometer, with an area of 1×1cm, at a bias of 1V. and a video modulation of 100Hz, is 1mV/W. The noise spectrum exhibits a 1/f rolloff till 1KHz, and is limited by the Johnson noise for higher frequencies. The NEP of the detector is 3WHz^–1/2 at a video modulation of 1KHz. It is possible to decrease the current NEP by fabricating bolometers with higher responsivities. Possible application areas are absolute power calibration and localized power density measurements at millimeter and submillimeter wavelengths.     

N-(邻-氯苯基)氨基乙酸铜(Ⅱ)和N-(邻-甲基苯基)氨基乙酸铜(Ⅱ)的合成、晶体结构和电子结构

合成了N-(邻氯苯基)氨基乙酸铜(Ⅱ)和N-(邻甲基苯基)氨基乙酸铜(Ⅱ)的单晶体,测定了它们的晶体结构,并对其电子结构进行EHMO计算。N-(邻氯苯基)氨基乙酸铜(Ⅱ)属单斜晶系,空间群P2₁/a.a=8.786(4),b=7.777(2),c=11.956(2)Å,β=96.01(3)°,V=812.4ų,Z=2,D_c=1.77g·cm^-3;N-(邻甲基苯基)氨基乙酸铜(Ⅱ)属单斜晶系,空间群P2₁/a,a=8.925(6),b=7.973(8),c=11.856(9)Åβ=96.23(6)°,V=838.6Å,Z=2,D_c=1.55g·cm^-3。两配合物互为异质同晶。配合物中,铜原子为分子的对称中心,并与两个配位体的两个羧基氧和两个氨基氮原子形成四方形配位结构,平均Cu-O键长为1.902Å,Cu-N为2.050Å。量子化学计算表明,在配位键的形成中,铜原子的d轨道的作用均不大,但配体中苯环上取代基的性质对Cu-N键强度有一定影响。     

ZnO超微粒子光催化氧化降解n-C7H16的研究

利用ZnO光催化氧化技术对气相n-C7H16进行了降解研究，考察了氧气、水燕气体积分数等因素对n-C7H16光催化氧化的影响，利用气相色谱－质谱联用仪和气相色谱仪对气相光催化反应过程中的气体组成进行了定性分析，并对主要中间产物丙醛进行了定量分析，结果发现，ZnO超微粒子光催化氧化n-C7H16的降解率较高，n-C7H16绝大部分被完全氧化成CO2，探讨了n-C7H16光催化氧化反尖的动力学行为及机理。     

A Highly Sensitive Spectrophotometric Assay of Bleomycins Based on the Fading Reaction of Some Halofluorescein Dyes

In weak acidic medium, anticancer antibiotics bleomycin A5 （BLMA5） and bleomycin A2 （BLMA2） can react with halofluorescein dyes such as erythrosin （Ery）, eosin Y （EY）, eosin B （EB） and rose bengal （RB） by virtue of electrostatic attraction and hydrophobic force to form the ion-association complexes, which can result in the fading reactions of four halofluorescein dyes. The maximum fading wavelengths of these four dyes were located at 527 nm for Ery, 515 nm for EY, 517 nm for EB and 546 nm for RB, respectively. The decrements of absorbance （AA） were directly proportional to the concentrations of bleomycin in a certain range. A new method for the determination of bleomycins anticancer drugs based on fading reactions of halofluorescein dyes has been developed. The method was not only highly sensitive but also simple and rapid. The molar absorptivities （ε） ranged from 1.5 × 10^5 to 7.5 × 10^5 L·mol^-1·cm^-1. It was applied to determination of the bleomycins in human serum, urine and rabbit serum samples. In this work, the spectral properties and the optimum reaction conditions were investigated. The structure of ion-association complexes and the reaction mechanism were discussed.