Preparing polymer brushes on polytetrafluoroethylene films by free radical polymerization

Films of polytetrafluoroethylene (PTFE) were exposed to sodium naphthalenide (Na/naphtha) etchant so as to defluorinate the surface for obtaining hydroxyl functionality. Surface-initiators were immobilized on the PTFE films by esterification of 4,4′-azobis(4-cyanopentanoic acid) (ACP) and the hydroxyl groups covalently linked to the surface. Grafting of polymer brushes on the PTFE films was carried out by the surface-initiated free radical polymerization. Homopolymers brushes of methyl methacrylate (MMA) were prepared by free radical polymerization from the azo-functionalized PTFE surface. The chemical composition and topography of the graft-functionalized PTFE surfaces were characterized by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance (ATR) FT-IR spectroscopy and atomic force microscopy (AFM). Water contact angles on PTFE films were reduced by surface grafting of MMA.     

Banach空间中凸映照的增长定理

本文利用凸映照的几何特征证明了一般复Banach空间中单位球上正规化双全纯凸映照的增长定理，即||f(x)||≤||x||/(1-||x||),A↓x∈B，对复内积空间，上述估计是最佳的。     

关于不完全双二次非协调板元的误差估计

本文在[1,2]的基础上,对不完全双二次板元作了进一步的讨论,不仅得到了最优的L~2—误差估计,改进了[1]的相应结果,而且利用“辅助元技巧”并结合正则Green函数法,得到了拟最优的L~∞—误差估计.     

矩阵方程（A^TXA，B^TXB=（C，D）的反对称解及其最佳逼近

本利用矩阵对的标准相关分解，得到了矩阵方程(A^TXB，B^TXB)=(C，D)反对称解存在的充分必要条件及通解表达式，同时给出了解关于已知矩阵的最佳逼近．     

超短强激光脉冲在等离子体隧道中传输的理论与数值模拟研究

研究了超短强激光脉冲在非扰动抛物型部分电离的预等离子体隧道中的传输特性.从Maxwell方程出发得到了两个包含衍射、三阶强度非线性、等离子体散焦、等离子体隧道聚焦以及相对论自聚焦等效应在内的激光场演化方程，即折射率方程和哈密顿-雅可比方程.在此基础 上得到了激光在等离子体隧道中传输的包络方程以及光斑半径与传输距离、隧道宽度等初始 参量的关系. 关键词： 等离子体隧道聚焦 相对论自聚焦 势阱     

Lanthanide Complexes for Oligomerization of Phenyl Isocyanate

IntroductionThestudyonthereactivitiesoflanthanidecomplexesto wardisocyanateshasattractedmuchattention .Ithasbeenre portedthatlanthanidealkoxides,1anddivalentdiaza pentadi enyllanthanidecomplexes2 canbeusedasthesinglecompo nentinitiatorsforisocyanatespolymerization .Recentlyourre searchgrouphasalsofoundthatlanthanoceneamide ,3diva lentaryloxideofsamarium4 ,5anddivalentsamarocene6 areallactivefortheoligomerizationofphenylisocyanate,andtheactivespeciesforthesethreesystemswereallsuccessfullyisolat…     

Apparatus for High-Resolution Solid Hydrogen Matrix Isolation Spectroscopy and Its Application

Apparatus integrating a Fourier transform-infrared (FT-IR) spectrometer and a mid-infrared difference frequency generation (DFG) laser spectrometer was built for the study of the matrix isolation spectrum in solid molecular hydrogen. A 3-cm-long molecular hydrogen crystal was grown in a liquid-helium Dewar, and its infrared absorption spectrum in the 1-5 μm region was recorded to test the system. The W₀(0) (ν=0←0, J=6←0) line around 2410 cm⁻¹ of solid hydrogen was investigated with the DFG laser spectroscopy. High-resolution matrix isolation spectrum of CO² co-deposited with hydrogen on a BaF₂ cold plate at liquid-helium temperature was studied.     

KF-Al2O3催化合成2-甲基-1-苄基苯并咪唑

苯并咪唑类杂环化合物具有杀菌、消炎、抗癌、抗氧化的活性,广泛用于食品的防虫和防腐,用于动、植物病毒的防治,人体疾病和肿瘤的防治[1-3],本文用KF Al2O3作催化剂,用DMF为溶剂,利用2 甲基苯并咪唑与苄基溴反应合成2 甲基 1 苄基苯并咪唑的新型方法,考察了诸因素对产率的影响,找出了最佳的反应条件。合成路线如下:1　实验部分1 1　仪器与试剂Brurer AM 500超导核磁共振波谱仪(溶剂CDCl3);CarloErbal1106型元素分析仪,NicoletIm pact410型红外光谱仪,KBr压片,HP1100型和Finnigan FTMS 2000型质谱仪(以上均由华东理工大学分析…     

Ultrasonic investigation of amorphous carbon in various frequencies at low temperatures from 2.1 to 300 K

Using pulse echo overlap measurement, the elastic behavior of amorphous carbon has been studied at ambient and low temperatures. The smaller ratio B/G of the bulk modulus to shear modulus and smaller Poisson's ratio σ at room temperature indicate that there is an intrinsic stiffening of transverse acoustic phonons in the amorphous carbon. The acoustic velocity and attenuation for longitudinal modes have been measured between 2.1 and 300 K at three frequencies of 7, 21 and 35 MHz, respectively. Their frequency and temperature dependence are observed. The elastic constant C₁₁ increases with decreasing temperature and show enhanced stiffening at low temperatures. In the 130-220 K region, the abnormal change and effect of longitudinal velocity and attenuation with temperature and frequency, and a phase transition associated with structure relaxations are discussed.