反应性复合乳液的合成、表征及其交联反应

利用种子半连续乳液聚合方法合成了核层或壳层带有环氧基以及壳层带有羧基的3种不同核/壳结构的乳胶粒子,通过物理共混带环氧基和羧基的乳胶粒子,得到了两种反应性复合乳液.利用透射电镜和激光动态光散射对乳胶粒子进行了表征,其粒径分布较窄,粒径分布的多分散系数为0.062,平均粒径约76 nm,乳胶粒子具有明显的核/壳结构.通过胶膜的凝胶率和膨胀率的测定和红外光谱分析对反应性复合乳液中乳胶粒子的扩散及交联反应进行了研究,并探讨了不同核壳结构复合乳液对涂膜机械性能的影响.研究表明,当反应性复合乳液中的环氧基和羧基分别分布在乳胶粒子的核层和壳层时,有利于聚合物分子链的充分扩散和化学交联反应的进行,从而提高涂膜的物理化学性能,当甲基丙烯酸缩水甘油酯(GMA)含量为10 wt%时,涂膜的拉伸强度达20.3 MPa.     

Upper bound of Kähler angles on the β-symplectic critical surfaces

Let (M,g) be a Kähler surface and \mathrm{\Sigma } be a \beta-symplectic critical surface in M. If L_q\left(\mathrm{\Sigma }\right) is bounded for some q>3, then we give a uniform upper bound for the Kähler angle on \mathrm{\Sigma }. This bound only depends on M,q,\beta and the L_q functional of \mathrm{\Sigma }. For q>4, this estimate is known and we extend the scope of q.     

用HPLC法测定咖啡因的不确定度

建立了HPLC法测定人尿中咖啡因定量分析的数学模型并推导出不确定度计算公式；通过对公式中各变量的分析，计算了各变量的不确定度，最后计算出合成标准不确定度。     

Using Toad Oocytes as an Ultrasensitive System for Estimating the Biological Activity of Trichosanthin

A sensitive bioassay for estimating the activity of Trichosanthin was developed by using intraoocyte microinjection as the technique and germinal vescicle breakdown as a marker. The GVBD inhibitory activity assay was million-fold more sensitive than the routinely used abortifacient activity assay. The detectable amount of Trichosanthin ranged from 0.5 to 100 pg. Since the least detectable dose was 0.5 pg, it made the assay suitable to analyse the microquantity of pure Trichosanthin used for studying the structure and function of the drug.     

在"高聚物的结构与性能"课程中应该引入的几个新概念

在“高聚物的结构与性能”课程教学中，很有必要向学生介绍高分子科学近十几年来的发展，尤其是在高分子凝聚态基本物理问题上的研究成果以及相关的新概念、新知识，特别是我国学者的贡献。本文较为详细地讨论了近年来作者在教学中介绍的几个新概念，如：动态接触浓度、单链凝聚态、凝聚缠结等。     

The synthesis and crystal structure of metal complexes S-alkyl-N-(ferrocenyl-1-methyl-methylidene)-dithiocarbazate and the study on their quenching the luminescence ofruthenium(bipyridine)_~3(2+)

The cobalt, nickel, copper, zinc and cadmium complexes of S-methyl-N-(ferrocenyl-l-methyl-methylidene)-dithiocarbazate (H-LSM) and S-benzyl-N-(ferrocenyl-l-methyl-methylidene)-dithiocarbazate (H-LSB) were synthesized and the crystal structure of Cd[Fe-C(CH3) = NNCSS. (CH3)]2 was solved by X-ray diffraction. The crystal is in the orthorhombic system with space group Pbca, cell parameters a=19.741(3), b=19.924(5), c=15.452(4) A, and the final factors of R=0.032. The study on quenching the luminescence of Ru(bpy)3 by those complexes showed that bimolecular quenching constants obtained from the Stern-Vohner constant and the excited-state lifetime were related to the redox potential of the quencher. Linear relationship is shown in the plot of logkq vs. E1/2(Q+/Q). The main factor which influences the quenching rate constant and the redox potential is the coordinating ability of the metal in the complex.     

Reactions of Laser Ablation-magnesium Plasma with Methanol Clusters

IntroductionReactions of metal ions with neutral molecules orclusters produce a variety of metal complex ions andother new series of cluster ions including cations andanions.The laser ablation-molecular beam(LA-MB)method has marked its relevance in the st…     

Synthesis and Crystal Structure of Bis(nitrate)- bis(N,N''''-dimethyl-N,N''''-dibenzenyl-urea)uranyl(Ⅱ)

1 INTRODUCTION Tri-butyl phosphate (TBP) has been widely used as the extraction reagent in U-Th fuel to separate uranium from thorium. But di-butyl phos- phate (DBP) and butyl phosphate (MBP), the radio- lytic products of TBP, exhibit some coordinated ability to the fission elements, such as Zr and Nb. The substitutes for TBP have being studied for several decades[1～4]. The physical and chemical properties of amides are similar to those of TBP and they selectively extract U(Ⅵ…     

[Co(ptma)(amp)Cl]2+体系的一反式经式异构体(m3[ZnCl4]·0.5H2O)的晶体结构

在合成[Co(bpma)(tn)Cl]²⁺体系配合物的实验中,得到[Co(ptma)(amp)Cl]²⁺体系的一反式(ptma中仲胺上的氢相对于Cl)经式异构体(m3[ZnCl₄]·0.5H₂O),其中bpma=N,N′-二(2-吡啶基甲基)胺,tn=1,3丙二胺,ptma=N-(2-吡啶基甲基)丙二胺,amp=2-(氨基甲基)吡啶。此配合物异构体构型选择性形成的原因可能主要是其结构中配体间C-H…π相互作用使之更稳定的结果。利用单晶X-射线衍射法测定的晶体学参数:单斜晶系,空间群C2/c,a=1.55978(19)nm,b=1.33324(16)nm,c=2.2077(3)nm,β=94.832(3)°,V=4.5748(10)nm³,D_c=1.696g·cm^-3,Z=8,F₀₀₀=2360,μ(MoKα)=23.72cm^-1,R=0.0475,R_w=0.1204。配合物离子中Co³⁺为六配位。晶胞中含8个配合物阳离子,8个[ZnCl₄]^2-阴离子及4个水分子,对映体的比例为1∶1。     

THE COMPARISON OF LANZHOU LOESS PROFILE WITH VOSTOK ICE CORE IN ANTARCTICA OVER THE LAST GLACIATION CYCLE

Loess near Lanzhou in the late Pleistocene is very sensitive to climatic fluctuations. The Beiyuan terrace profile in Linxia City, of which the curve of susceptibility tallies with the trend of isotopic curves of Vostok 2083 m ice core in Antarctica, is 35m thick. There are five layers of paleosols under Malan loess(L_1). Upper three layers (S_(1-a),S(1-b)and S_(1-c) correspond to three warm stages in last interglaciation, Interstadial of Last Glacial (C stage in Antarctic ice core)was clearly recorded in the Beiyuan profile, in which three layers of paleosols and two of loess were formed. The lowest section of the profile belongs to penultimate glaciation, in which fossils of cold-drought-resistant mammal and mollusc have been discovered.