Micelles Formed by Cylindrical Brush‐Coil Block Copolymers

Summary: Amphiphilic cylindrical brush‐coil block copolymers consisting of a polystyrene coil and a cylindrical brush block with poly(acrylic acid) side chains are prepared by ATRP of t‐butylacrylate from a block comacroinitiator. Upon acidolysis of the poly(t‐butylacrylate), water‐soluble polymers were obtained that were observed to form micelles consisting of 4–5 block copolymers on average in aqueous solution. The star‐like nature of such micelles was clearly visualized by scanning force microscopy.

Schematic of coil‐cylindrical brush block copolymer PS‐b‐(PⁱBEMA‐g‐PAA), its AFM image clearly showing the main chain and the PAA corona of the cylindrical brush block.     

Analytical solution of radiation sound pressure of double cylindrical shells in fluid medium

ＩｎｔｒｏｄｕｃｔｉｏｎＳｏｕｎｄｒａｄｉａｔｉｏｎｆｒｏｍｔｈｅｄｏｕｂｌｅｓｈｅｌｌｓｗｈｉｃｈａｒｅｔｈｅｍａｉｎｓｔｒｕｃｔｕｒｅｏｆｓｕｂｍａｒｉｎｅｈｕｌｌｓｕｎｄｅｒｅｘｃｉｔａｔｉｏｎｉｎｆｌｕｉｄｍｅｄｉｕｍｉｓｖｅｒｙｉｍｐｏｒｔａｎｔｆｏｒｓｔｕｄｙｉｎｇｔｈｅｓｕｂｍａｒｉｎｅｈｉｄｉｎｇｔｅｃｈｎｏｌｏｇｙ .Ｆｏｒｔｈｅｖｉｂｒａｔｉｏｎｃｈａｒａｃｔｅｒｉｓｔｉｃｏｆｄｏｕｂｌｅｃｏｎｃｅｎｔｒｉｃｓｈｅｌｌｓ,ｉｔｈａｓｂｅｅｎｓｔｕｄｉｅｄｏｎｔｈｅｏｒｙａｎｄｅ…     

复合材料层合剪切圆柱曲板在侧压作用下的后屈曲

基于Reddy高阶剪切变形理论的Kármám-Donnell型非线性壳体方程,给出复合材料层合剪切圆柱曲板在侧压作用下的后屈曲分析。将壳体屈曲的边界层理论推广到复合材料层合剪切圆柱曲板受侧压作用的情况。相应的奇异摄动法,用于确定圆柱曲板的屈曲荷载和后屈曲平衡路径。分析中同时考虑非线性前屈曲变形和初始几何缺陷的影响。数值算例给出完善和非完善,中等厚度正交铺设层合圆柱曲板的后屈曲荷载-挠度曲线。讨论了横向剪切变形,曲板几何参数,铺层数,铺展方式和初始几何缺陷等各种参数变化的影响。     

Polar Oscillation of Interface and Surface Optical Phonons in Free-Standing Cylindrical Quantum-Well Wires

Under dielectric continuum approximation, interface optical (IO) and surface optical (SO) phonon modes as well as the corresponding Fro^ehlich electron-phonon interaction Hamiltonian in a free-standing cylindrical quantum-well wire (QWW) are derived and studied. Numerical calculations on GaAs/AlzGa1-x As cylindrical QWW are performed. Results reveal that there are two branches of IO phonon modes and one branch of SO phonon mode, and the dispersion frequencies of IO or SO phonon modes sensitively depend on the Al mole fraction x in AlzGa1-x As material and the wavevector in z direction, kz. With the increasing of kz and quantum number m, the frequency of each IO mode approaches one of the two frequency values of the single GaAs/AlxGa1-x As heterostructure, and the electrostatic potential distribution of the phonon mode tends to be more and more localized at a certain interface or surface, meanwhile, the coupling between the electron-IO and -SO phonons becomes weaker.     

大挠度圆柱壳在温度场中的热弹耦合振动分析

对温度场与与应力场耦合时的圆柱壳的非线性热弹耦合的振动问题,推导得到了基本的振动方程,热传导方程和协调方程,对短圆柱壳运用伽辽金(Galerkin)法求解,得出振幅随时间变化的数值解,得到一些有价值的结论．即随着温度幅值和耦合系数的增大,振动衰减的速度变缓,热弹耦合效应减弱．随着长径比、长厚比的增大,振幅衰减的速度变快,同时热振动频率也随之增大,即热弹耦合效应增强．耦合系数越大,轴向应力、轴向力以及轴向弯矩越小．     

圆棒介质波导的电磁波传播特性

通过简单的数学分析,推导圆棒介质波导的导模传播条件及特征方程,讨论电磁波在圆棒介质波导中的传播特性。     

Nonlinear Theory of Dynamic Stability for Laminated Composite Cylindrical Shells

ＩｎｔｒｏｄｕｃｔｉｏｎＷｈｅｎｃｏｍｐｏｓｉｔｅｃｙｌｉｎｄｒｉｃａｌｓｈｅｌｌｓａｒｅｕｎｄｅｒｔｈｅａｃｔｉｏｎｏｆｄｙｎａｍｉｃｌｏａｄｉｎｇ ,ｔｈｅｙｍａｙｆａｌｌｉｎｄｙｎａｍｉｃｂｕｃｋｌｉｎｇｏｒｄｙｎａｍｉｃｉｎｓｔａｂｉｌｉｔｙ .Ｉｆｔｈｅｄｙｎａｍｉｃｌｏａｄｉｓｓｕｄｄｅｎｌｙａｐｐｌｉｅｄ ,ｏｒｉｔｉｓｃｈａｎｇｉｎｇｉｎｓｔａｎｔａｎｅｏｕｓｌｙ ,ｓｕｃｈａｓｉｍｐｕｌｓｉｖｅｌｏａｄｉｎｇ ,ｔｈｅｎ ,ｄｙｎａｍｉｃｂｕｃｋｌｉｎｇｗｉｌｌｈａｐｐｅｎｆｏｒｔｈｅｓｈ…     

柱面Love波频散分析与SH波场的数值计算

对贴井壁环型剪切源在柱状双层弹性介质中激发的SH波场进行了理论求解,导出了柱面Love波频散方程,讨论了柱面Love波存在的条件及其区域.通过数值计算考察了柱面Love波的频散特性和激发强度,发现最低阶柱面Love波具有截止频率,这与平面半空间双层弹性介质模型下的Love波无截止频率的特征不同.渐近分析与数值考察都表明,井径r₁→∞时,柱面Love波频散方程趋向平面双层半空间的Love波方程,柱面Love波的截止频率趋于零.全波计算还显示用激发SH波来探测侵入带外原状地层的横波信息是一个十分简洁的途径..     

聚氨酯弹性体的相区相容性和阻尼性能研究

合成了一系列含有不同软段的聚氨酯嵌段共聚物及接枝共聚物,并测试了其动态力学性能,结果表明,聚氨酯共聚物的相容性与大分子的链结构有关,接枝链的存在对聚氨酯嵌优共聚物相空性和阻尼性能有很大影响。     

茂金属乙丙弹性体技术进展

论述了茂金属乙丙弹性体的合成,表征、反应机理,工业化进程化以及工业化应用,着重介绍了茂金属催化体系和茂金属乙丙弹性体的结构和性能。