有机催化不对称Diels-Alder反应的研究进展

综述了国内外不对称Diels-Alder反应的最新研究成果,就Lewis碱、Bronsted碱、有机双功能催化剂以及Br(o|¨)nsted酸作为催化剂来催化该反应分别进行了较全面的阐述。     

A critical survey of experimental cross section data, comparison with nuclear model calculations and estimation of production yields of Br and Kr in no-carrier-added form via various nuclear processes

Experimentally investigated nuclear reactions for production of no-carrier-added ⁷⁷Br and ⁷⁷Kr were critically surveyed. The survey covered nine reactions for the formation of ⁷⁷Br and six reactions for ⁷⁷Kr. Both radionuclides are simultaneously produced in many of the studied nuclear processes. The experimental data were compared with the results of nuclear model calculations based on the computer code ALICE-IPPE and the third version of TALYS-based Evaluated Nuclear Data Library, TENDL-2010. Good agreement was found over extended energy regions for the p-, ³He- and α-particle induced reactions on several target materials. In case of d-induced reactions, however, considerable discrepancies were noted between the experimental and theoretical data. The concordant sets of experimental cross section data for each reaction were fitted by a polynomial function to obtain a trend curve. From the thus obtained trend curves the yields of both ⁷⁷Br and ⁷⁷Kr were calculated. A discussion of suitable production routes is given.     

蒙药鹅绒藤扫描电镜的观察研究

目的：为蒙药鹅绒藤药材鉴定研究提供地上部分表面的微形态依据。方法：采用扫描电子显微镜技术进行观察研究。结果：鹅绒藤叶片上下表皮、内外果皮、种子背腹面和花粉块的微形态各异。结论：为鹅绒藤药材微形态鉴定和生物学研究提供参考依据。     

荔枝草保健茶的制作工艺研究

以抽茎前期、花前期、结果后期采收的荔枝草为原料,研发出一种新型保健饮料--荔枝草保健茶;对其生产过程中的原料筛选、杀青和干燥工艺参数分别进行了研究。结果表明,以抽茎前期采收的荔枝草为原料,经除杂、整形、微波杀青（480W,150s）、揉捻（15min）、干燥（102℃,140min）、冷却、包装等工序,能生产出色泽、香气、滋味和汤色俱佳的荔枝草保健茶。      

煤矸石中痕量钍的光度法测定

研究了 2 (5 溴 2 吡啶偶氮 ) 5 二乙氨基苯酚 (5 Br PADAP)作为微量钍的显色剂。在pH 5 .0的HAc NaAc缓冲体系中和非离子OP乳化剂的存在下 ,5 Br PADAP和钍 (Ⅳ )的络合物在λmax=5 85nm处的表观摩尔吸光系数为 1.3 5× 10 5L·mol- 1 ·cm- 1 。钍 (Ⅳ )的质量浓度在 0～ 0 .5 0mg·L- 1 范围内符合比耳定律。钍的加标回收率在 98.5 %～ 10 3 .6%之间 ,结合PMBP萃取分离 ,可用于测定煤矸石中的微量钍     

HTSC, negativeU, and RVB; cuprates and oxyhalides

Attention is redrawn to published work on a negativeU perception of how HTSC develops in the mixed-valent cuprates and bismuthates. The mechanism that has been proposed is one of a two-subsystem, three-center, dynamic seeded disproportionation, driven by strong shell-closure effects in high-valent environment. In pursuing why alternative proposals seem less viable we have made an examination of the oxyhalide systems TiOCl(Br) substituted with scandium. Thesed ¹ oxyhalides are prime candidates for RVB behavior, though not, it seems, superconductivity.     

Acid-based Catalysis in Zeolites Investigated by Density-Functional Methods

Zeolites are a unique class of microporous aluminosilicates with multiple applications as molecular sieves, detergents, desiccants and acid catalysts. Their catalytic activity is determined by Br?nsted and Lewis acid sites created by protonation or activation by metallic cations. The reactivity of the acid sites is strongly influenced by the geometry and the flexibility of the zeolitic framework. Recent investigations of the reactivity of zeolites and simulations of catalytic reactions based on periodic-density-functional calculations are reviewed.     

Removal of basic nitrogen compounds from fuel oil with [C4mim]Br/ZnCl2 ionic liquid

Metal-based ionic liquid [C₄mim]Br/ZnCl₂ was synthesized, and its structure was characterized using FTIR spectroscopy and a mass spectrometer. The denitrogenation performance of the ionic liquid was investigated using coker diesel oil as feedstock. Experiment results showed that [C₄mim]Br/ZnCl₂ presented a good denitrogenation performance, obtaining about 94.95% basic N-removal efficiency under the condition with a temperature of 50°C, 1:1 (w/w) IL:oil, extraction time of 30 min. In addition, the basic N-removal efficiency can still reach above 50% at 1:7 IL/oil (w/w) during four recycles of the ionic liquid.     

新型二羟基手性磷酸催化剂的合成

以1,1'-联二萘酚〔(R)-BINOL〕为原料,在n-BuLi的作用下对BINOL的3,3'位上进行修饰,获得(R)-3,3'-双(二苯基羟基甲基)-2,2'-二羟基-1,1'-联二萘(Ⅰc),并通过羟基选择性保护,磷酸化反应,将其转化为具有潜在能力的手性磷酸催化剂(Ⅱa),收率52%。     

Mechanism of charge recombination and IPCE in ZnO dye‐sensitized solar cells having I−/I and Br−/Br redox couple

The influence of intensity and wavelength variation on the solar cell parameters of two different ZnO‐based liquid state DSSCs named as Cell (A) ZnO/EosinY/LiI and Cell (B) ZnO/EosinY/LiBr was studied. It was found that V_oc and I_sc depend logarithmically and linearly on light flux, respectively, which indicates that light absorption and carrier diffusion do not limit the solar cell efficiency. The data was analyzed to ascertain the charge recombination mechanism between conduction band electrons and the electrolytes. The regeneration of dye due to I⁻/I₃ and Br⁻/Br redox couple was examined by studying the wavelength dependence of IPCE. An estimation of series and shunt resistance is made using two methods: (i) different illumination method (ii) single I–V curve, for the two cells in order to understand the role of the electrolyte in controlling the solar cell parameters. Copyright © 2010 John Wiley & Sons, Ltd.