在非光滑区域中含有透射条件的椭圆方程边值问题

本文研究非光滑区域Ω上的椭圆型方程透射问题。在Ｓｏｂｏｌｅｖ空间中，通过变分的形式，引进弱解的讨论，证明了解的存在、唯一和正则性质。     

四-4-(2-正丁氧基乙氧基-羰基)酞菁铜(Ⅱ)在四氢呋喃和氯仿中的二聚物

本文通过对四-4-(2-正丁氧基乙氧基-羰基)酞菁铜(Ⅱ)在THF和CHCl_3溶液可见光谱的分析表征了它在一定的浓度范围(10~(-7)～10~(-5)mol/L)存在单分子和双分子聚集态之间的动态平衡。在THF和CHCl_3溶液中,双分子二聚物的离解常数K_d=C~2m/C_D分别是2.08(±0.05)×10~(-6)mol/L和1.10(±0.06)×10~(-6)mol/L。利用作图法,绘制出纯单分子和纯二聚物的可见光谱图。最后,对两种溶液可见光谱的区别进行了讨论。     

具有反聚电解质溶液行为的两性聚合物

大分子链上同时含有正负电荷基团且其数目相等的两性聚合物，具有独特的反聚电解质溶液行为和广阔的应用前景。本文就其合成、溶液特性及应用进行了概述。     

ABS/clay nanocomposites obtained by a solution technique: Influence of clay organic modifiers

Acrylonitrile-butadiene-styrene (ABS) polymer/clay nanocomposites were produced using an intercalation-adsorption technique from polymer in solution: polymer/clay suspensions were subjected to ultrasonic processing to increase the effectiveness of mixing. Several kinds of organically modified layered silicates (OMLS) were used to understand the influence of the surfactant nature on the intercalation-exfoliation mechanism. We show that only imidazolium-treated montmorillonite (DMHDIM-MMT) is stable at the processing temperature of 200 °C, used for hot-pressing, whereas alkyl-ammonium modified clays show significant degradation.The morphology of ABS based polymer nanocomposites prepared in this work was characterized by means of wide angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM). Dynamic-mechanical analysis (DMA) was used to determine the storage modulus and damping coefficient as a function of temperature, and to investigate the correlations between mechanical properties and morphology of the nanocomposites. The thermal stability was assessed by means of thermogravimetric analysis (TGA). DMA and TGA show that the nanocomposites based on imidazolium-modified clay out-perform the nanocomposites based on quaternary-ammonium-modified clays in terms of mechanical properties and thermal stability.     

红薯提取液荧光猝灭的Zn2+检测

人体大量摄入锌时易引起中毒,对锌污染的监测十分重要[1,2].锌离子的检测方法主要有电化学分析法[3-5]、光化学分析法[6,7]、原子吸收分光光度法[8]等.     

Nd—Al双金属活性体对异戊二烯的溶液聚合

近年来,对于稀土Ziegler-Natta催化剂活性体的研究比较活跃。使用催化剂活性体可以消除剩余烷基铝等因素对聚合反应的影响,比以前所用的多组分混合物的催化体系更客观地反映出聚合过程。我们在以前工作的基础上,从体系中分离出Nd-Al双金属活性体,并用于引发异戊二烯溶液聚合,探讨不同聚合条件下异戊二烯溶液聚合的规律,以利于对稀土催化聚合反应的深入了解。     

A new viscometric criterion for polymer-polymer interaction

Based on a simple cluster theory recently proposed for the viscosity of polymer dilute solution, a new viscometrical criterion was suggested to probe the interaction between unlike polymers. The new criterion was applied into some polymer mixture solutions to study the polymer-polymer interactions. It was found the new criterion is more reasonable.     

Mechanistic Analysis of Solution Reactions by Non-Isothermal Calorimetry

For the rapid kinetic and energetic analysis of reactions in solution (τ_20°C > 10^-4s) by differential thermal analysis (DTA), the following thermogram parameters are defined as characterizing the start of the reaction: 1. initial temperature, 2. activation energy of the initiation reaction. In conjunction with the shape index (asymmetry of the DTA curve) and the half width of the DTA curve referred to standard physical conditions (cell constant, heating rate, and temperature difference), these quantities allow a simple distinction between one-step reactions of first and second order and composite reactions. It is possible to recognize whether a process involves parallel, successive, or equilibrium reactions, or combinations of these. The reaction mechanism can be clarified in many cases by measurements at various concentrations and heating rates and by discussion of the enthalpy values. The shortened method described in this report for the evaluation of the thermograms was derived with the aid of an analog computer and checked experimentally.     

壳聚糖及其衍生物溶液浇铸膜的结构研究

用偏光显微镜小角光散射、扫描电镜和大角度X-光衍射技术研究了壳聚糖及其衍生物丁酸壳聚糖、苯甲酸壳聚糖的溶液浇铸膜的结构。用低于液晶临界浓度的稀溶液能制备具有液晶织构的膜。观察到指纹状织构、正光性滴状织构和负光性滴状织构．后两种滴状织构内分子自组织构型分别为辐射型和双极型。     

Studies on the photophysical characteristics of poly(carboxylic acid)s bound protoporphyrin IX and metal complexes of protoporphyrin IX

The copolymers of methacrylic acid with protoporphyrin IX (PPIX) and the metal complexes, zinc protoporphyrin IX and magnesium protoporphyrin IX were synthesised and characterised. Corresponding acrylic acid copolymers were also synthesised. The steady state absorption and fluorescence spectral properties of the macromolecular bound fluorophores PPIX, Zn-PPIX and Mg-PPIX were investigated. Poly(methacrylic acid) bound protoporphyrin IX, zinc protoporphyrin IX and magnesium protoporphyrin IX show an increase in the fluorescence intensity and lifetime with increase in the pH in the range 2-8 with a marked transition around pH 6.0-7.0. The fluorophore concentration in the dilute solution of the copolymers is micromolar and the fluorophore to the carboxylic acid monomer ratios in the copolymer is around 10⁻³. The molecular weight of the copolymers is 100 ± 10 kD. The fluorescence decay curves of all the fluorophore bound polymers follow biexponential decay fit independent of pH. Poly(MAA-co-PPIX) and poly(MAA-co-MgPPIX) undergo well marked pH induced structural transitions in the pH range of 6.0-7.0 whereas poly(MAA-co-ZnPPIX) undergoes pH induced structural transitions in the pH range of 4.0. In the case of polyacrylic acid copolymers the changes observed in the steady state and time resolved fluorescence studies are less marked. The distinct hydrophobic and hydrophilic environments experienced by the fluorophore bound to PMMA are attributed to the dynamics of the macromolecules in dilute aqueous solutions manifested by the α-methyl group present in the copolymer. The studies carried out using the fluorophores in the time windows from 2 ns to 12 ns indicate evolving trends in the dynamic coiling and reverse coiling of poly methacrylic acid chain.