冠醚化Schiff 碱配合物金属胶束催化BNPP水解动力学

研究了两种新的冠醚化Schiff 碱过渡金属配合物与表面活性剂Brij35(聚氧乙烯(23)十二烷基醚)形成的金属胶束对BNPP（对硝基苯酚磷酸二酯）的催化水解反应. 探讨了催化反应机理, 建立了一种金属胶束催化BNPP水解的动力学数学模型; 计算了模拟酶催化反应的相关参数和表观活化能. 结果表明, 此类金属胶束作为模拟水解金属酶对BNPP水解反应表现出良好的催化活性.     

Preparation of a new metallomicelle catalyst for the hydrolysis of bis(4-nitrophenyl) phosphate

A new metallomicellar system containing cerium(III), a macrocylic polyamine ligand, and the nonionic surfactant Brij35(polyoxyethylene(23) lauryl ether) was prepared and used as a catalyst in the hydrolysis of bis(4-nitrophenyl) phosphate (BNPP). Catalytic rate of the BNPP hydrolysis was measured kinetically using the UV-VIS spectrophotometric method. The results indicate that the metallomicellar system has relatively high stability and excellent catalytic function in the BNPP hydrolysis; also, the reaction rate of the BNPP catalytic hydrolysis increased by a factor of ca. 1 × 10¹⁰ compared to the BNPP spontaneous hydrolysis due to the catalytic effect of the active species and the local concentration effect of the micelles in the metallomicellar system. Experimental results also showed that the mono-hydroxy complex containing the macrocyclic polyamine ligand and cerium(III) is the real active species in the BNPP catalytic hydrolysis, and that the micelles provide a useful catalytic environment for the reaction. On basis of the research results, the reaction mechanism of BNPP catalytic hydrolysis has been proposed.     

Ti掺杂NbSe2电子结构的第一性原理研究

采用基于密度泛函理论框架下的第一性原理平面波超软赝势方法, 计算了理想2H-NbSe₂和Ti掺杂2H-NbSe₂晶体的几何结构及电子结构; 对掺杂前后超胞的能带图、态密度及分波态密度图进行了分析. 结果表明, 掺杂后费米能级附近能量区域的电子态密度出现了较高的峰值, 且费米能级位置发生了改变. 理论上可以认为Ti的掺杂会使得NbSe₂的导电性增强, 有利于开发新型的电接触复合材料.     

Divergence points of self-similar measures satisfying the OSC

Recently, Barreira and Schmeling (2000) [1] and Chen and Xiong (1999) [2] have shown, that for self-similar measures satisfying the SSC the set of divergence points typically has the same Hausdorff dimension as the support K. It is natural to ask whether we obtain a similar result for self-similar measures satisfying the OSC. However, with only the OSC satisfied, we cannot do most of the work on a symbolic space and then transfer the results to the subsets of Rd, which makes things more difficult. In this paper, by the box-counting principle we show that the set of divergence points has still the same Hausdorff dimension as the support K for self-similar measures satisfying the OSC.     

An Improved Method for Testing Weak VOCs in Dry Plants with a Purge and Trap Concentrator Coupled to GC-MS

The purge and trap (P&T) technique was improved for measuring the release of organic compounds with weak volatility (weak VOCs) from dry plant materials. Using distilled water as a dispersant, the plant tissues were mulled and placed in the purge tube of a P&T concentrator. Then the sample-containing purge tube was heated to 80 °C with helium as the carrier gas, and the purged volatiles were preconcentrated in the trap prior to analysis with GC-MS. The VOCs in Chinese herbal medicinal plants Swertia tetraptera, Saussurea involucrate and S. lacostei, which had been stored dry for 1–2.5 years were assayed with this improved method and conventional P&T techniques. Our results show this new P&T method had great promise for determining the VOCs in dry plant materials. Using this new technique, we identified 38 weak VOCs with a large peak area from the dry samples. In contrast, less than five VOCs were detected by the conventional P&T method. So the improved heat-purge and trap system showed to be more efficient for measuring the release of the weak VOCs from dry plant materials.     

Androstane and monoterpene glucoside sinapoyl ester from Cynanchum amplexicaule SIEB. et ZUCC

A new androstane, 17beta-hydroxy-androsta-4,6,15-trien-3-one (1) and a new monoterpene glucoside sinapoyl ester, (3R)-8-hydroxylinalool 3,8-di-O-beta-D-(6'-O-E-sinapoyl)glucopyranoside (2) were isolated from the roots of Cynanchum amplexicaule SIEB. et ZUCC. (Asclepiadaceae), along with two known monoterpenes, (3R)-8-hydroxylinalool (3) and (6R)-menthiafolic acid (4). Their structures were elucidated on the basis of analyses of physical, chemical, and spectral data.     

系列二肽链键联的卟啉-蒽醌及其金属配合物的微波合成及电子转移性质

本文报道了系列二肽链键联的卟啉-蒽醌及其金属配合物的微波合成,化合物的结构分别经UV-Vis,IR,1H NMR及元素分析确证。探讨了化合物分子内电子转移性质（IETP）,并讨论了结构对IETP的影响。     

A Facile Photo-cross-linking Method for Polymer Gate Dielectrics and Their Applications in Fully Solution Processed Low Voltage Organic Field-effect Transistors on Plastic Substrate

A simple and effective photochemical method was developed for cross-linking of polymer gate dielectrics.Laborious synthetic processes for functionalizing polymer dielectrics with photo-cross-linkable groups were avoided.The photo-cross-linker,BBP-4,was added into host polymers by simple solution blending process,which was capable of abstracting hydrogen atoms from polymers containing active C―H groups upon exposure to ultraviolet(UV) radiation.The cross-linking can be completed with a relatively long wavelength UV light(365 nm).The approach has been applied to methacrylate and styrenic polymers such as commercial poly(methylmethacrylate)(PMMA),poly(iso-butylmethacrylate)(Pi BMA) and poly(4-methylstyrene)(PMS).The cross-linked networks enhanced dielectric properties and solvent resistance of the thin films.The bottom-gate organic field-effect transistors(OFETs) through all solution processes on plastic substrate were fabricated.The OFET devices showed low voltage operation and steep subthreshold swing at relatively small gate dielectric capacitance.     

Synthesis and structures of two three-dimensional hybrid materials based on vanadium polyoxoanions and macrocyclic metal complexes

Transition Metal Chemistry - The reactions of transition metal macrocyclic complexes [ML](ClO4)2 (L?=?1,8-diethyl-1,3,6,8,10,13-hexaazacyclotetradecane, M=Ni, Cu) with NH4VO3 gave two...     

纳米PbO2修饰电极安培检测器流动注射法快速测定化学需氧量

采用以纳米PbO₂修饰电极为工作电极的安培检测器,用流动注射法快速检测水体中的化学需氧量(COD).根据纳米PbO₂修饰电极催化氧化电流的大小测定样品的COD值,在50-1 200 mg/L COD的范围内,电流响应与标准水样中的COD_Cr值呈线性关系,检出限为20 mg/L.该法不需对水样进行预处理,不使用有毒试剂,无二次污染,具有快速、简便、进样量少及工作电极使用寿命长等优点,与COD_Cr国家标准分析法对比具有较好的相关性.