苯并噁嗪中间体/蛭石插层纳米复合物热固化行为的研究

通过对双酚A型苯并嗪中间体 (BOZ A) 蛭石插层纳米复合物固化过程的分析表明长链烷基铵阳离子对BOZ A的热开环聚合反应没有表现出催化作用 ,也不影响纳米复合物的结构形态 .不同蛭石含量的插层纳米复合物 ,在形成不同纳米分散状态的纳米复合物的过程中 ,蛭石晶片对BOZ A的热开环聚合具有明显不同的阻碍作用 ,蛭石含量为 3%的插层纳米复合物 16 0℃的凝胶化时间较纯树脂延长约 7min ,活化能升高约8kJ mol,固化反应热焓降低约 14J g ,使得固化物的固化程度较纯树脂降低约 7%～ 10 % ,阻碍作用最大 ,其它含量的次之     

Natural anti-HIV agents. Part 3: Litseaverticillols A-H, novel sesquiterpenes from Litsea verticillata

Bioassay directed-fractionation led to the identification of litseaverticillols A-H (1-8) from the leaves and twigs of Litsea verticillata Hance. These new sesquiterpenes possess a unique skeleton that was recently designated as ‘litseane’. The structures of these compounds were determined by spectroscopic means including 1D and 2D NMR data. Structural configurations were determined by ROESY experiments. Mosher ester reactions and optical rotation measurements established the sesquiterpenes 1-8 as racemates. Isolates 1-8 inhibited HIV-1 replication in HOG.R5 cells with IC₅₀ values ranging from 2 to 15 μg/ml (8-58 μM) while affecting the growth of HOG.R5 at concentrations 2-3-fold higher. Based on this data, structure-activity relationships can be discerned, suggesting compounds of this class are good candidates for analog production.     

CARRIER PHOTOGENERATION IN POLY（N-VINYL-CARBAZOLE）-BASED PHOTOCONDUCTIVE THIN-FILM DEVICES

In this paper, photoexcitation processes in the bilayer devices based on inorganic materials and poly（N-vinylcarbazole） （PVK） were investigated. In order to clarify the roles of inorganic materials in photoconductive properties of bilayer devices, TiO2 and ZnS were chosen to combine with PVK. A model for generation of photocurrent （Iph） in single layer device of PVK was obtained. It is deduced that the recombination rate constant （Pcomb） and the ionization rate constant （y） ofexcitons should be considered as the most important factors for Iph. For inorganic materials （TiO2 or ZnS）/PVK bilayer devices, in reverse bias of-4 V, the photocurrent of 115 mA/cm^2 in the TiO2/PVK device was observed, but the photocurrent in the ZnS/PVK device was only 10 mA/cma under the illumination light of 340 nm and the light intensity of 14.2 mW/cm^2. The weaker photocurrent is attributed to the absorption of ZnS within UV region and the energy offset at the interface between PVK and ZnS, which impedes the transport of charge carriers.     

改进的蝗虫优化算法在双目标应急物资中心选址问题中的应用

近年来世界各地频发灾情疫情等紧急事件,严重影响人民的生活物资保障。在这种情况下,急需建立应急物资中心来缓解燃眉之急。该类问题通常面临资源稀缺并且时间相对紧迫的处境,因此需要在短时间内获得合理的应急设施选址方案来提升服务的质量和效率。本文对应急物资中心选址问题展开研究,提出一种考虑后续运输成本以及有概率发生紧急事件而导致无法正常运送物资的双目标离散选址模型,并为此设计一种二进制多目标蝗虫优化算法。该算法采用模糊关联熵系数来引导迭代更新,同时为其添加外部档案,最优解选择机制和竞争决策机制来提升算法性能。多次数值实验表明该算法的计算效率和求解质量较高,可作为应急物资中心选址问题的一种可行且有效的算法。     

Carbon Nanotubes Grown on Sepiolite as Catalyst Carrier

Multi-walled carbon nanotubes were synthesized by the catalytic decomposition of acetylene at 750℃ over sepiolite powder,which was treated with aqueous cobalt nitrate. It is expected that the composite with high specific area will have high capacity of hydrogen storage.     

Syntheses and structures of magnesium pyridine thiolates--model compounds for magnesium binding in photosystem I

Novel magnesium pyridine-2-thiolates were prepared by using alkane elimination chemistry. The resulting complexes display a metal coordination environment composed of sulfur/nitrogen bonding from the intramolecularly stabilized mercaptopyridine ligand, in addition to coordination by the oxygen centers from two THF donors. The compounds are well-suited model compounds for the magnesium centers in Photosystem I, in which magnesium, situated in the central chlorophyll ligand, is bound to sulfur from a nearby methionine residue. All compounds were characterized by (1)H, (13)C NMR, and IR spectroscopy, in addition to Xray crystallography.     

流动注射-结晶紫-磷钼杂多酸离子缔合体系光度法测定水中痕量正磷酸盐

在一定的酸度条件下,结晶紫与磷钼杂多酸离子缔合物的流动注射分光光度法可直接测定痕量磷.灵敏度高,重现性和选择性好.水中常见离子不干扰痕量磷的测定,工作曲线的线性范围为0～500μg·L~(-1)的磷,检出下限达1.0μg·L~(-1),以120h~(-1)采样频率,对各种天然水样进行测定,回收率为92.5%～105.0%,相对标准偏差为0.1%～6.7%.     

POLYMERIZATION OF OCTAFLUOROCYCLOBUTANE IN GLOW DISCHARGE Ⅱ. ESCA AND IR CHARACTERIZATION OF POLYMER STRUCTURE*

In a capacitively coupled discharge with external electrodes, He, H_2, N_2 or Ar were used as plasmagas, polymerization of octafluorocyclobutane was carried out under different conditions by varyingdischarge power, pressure, plasma gas and plasma-gas/monomer ratio. Structure of polymerizedproducts was characterized by IR spectroscopy and ESCA measurement. It was found that therewere six elements in the products, i.e. C, F, Si, O, N and H. The probably existed groups in poly-mers wer investigated. By analyzing the resolved peaks of C_(1S) region in ESCA spectra, effect of thereaction conditions on degree of branching of the polymerized products and the relationship of thepolymer structure wth the mechanism of the competitive ablation and polymerization process werestudied. In addition, polymer deposition process occurring in glow discharge was discussed.     

PHBV/HA骨修复材料的研究

利用硝酸钙与磷酸钠的水溶液制备羟基磷灰石(HA)，同时在HA生成过程中与聚羟基丁酸一戊酸酯(PHBV)复合，探索了HA增强PHBV使之适于作为骨修复材料的一种新途径。结果表明，HA的均匀分散增进了复合材料中两相问的相互结合，能明显地提高复合材料的力学性能。     

四苯基卟啉铂电致发光性能的研究

四苯基卟啉铂(PtTPP)可以作为红光掺杂材料制备有机电致发光器件，采用的器件结构为[ITO／CuPc／NPB／BePP2：PtTPP／LiF／Al]，其中BePP2：PtTPP的共沉积膜作为发射层．实验结果表明在发射层中存在着从BePP2到PtTPP的能量传递．通过改变掺杂层中PtTPP的浓度来考察器件的性能，当PtTPP的掺杂浓度在8％(物质的量比)时，器件呈现纯正的红光发射，发射峰位于668nm，器件的效率为0．004lm／W．