含二氮杂萘酮结构聚醚砜酮膜的微波等离子体处理研究

含二氮杂萘酮结构型聚醚砜酮(ＰＰＥＳＫ)是近年来本研究组开发成功的新型耐高温聚合物[1].该聚合物具有优异的力学性能和突出的耐热性,玻璃化转变温度(Ｔｇ)为265～305℃(随砜酮比不同而变化),其结构式如下:ＯＮＮＯＳＯＯＯＮＮＯＣＯ　　研究表明,用ＰＰＥＳＫ制成的气体分离膜对Ｏ2/Ｎ2、ＣＯ2/Ｎ2有良好的气体渗透性和透过选择性[2,3],但由于其亲水性不高进而限制了它在纳滤膜和反渗透膜等方面的应用,因此有必要对其进行改性.目前,常用的膜及膜材料改性的方法有磺化、氯甲基化季胺化、接枝等化学改性和低温等离子体与辐射等物理改性.其…     

溶剂效应的TLSER描述及其在几类异构化反应中的应用

建立了适合于描述党溶剂效应的理论线性溶剂化能相关(TLSER)模型。并用该模型对四类异构化反应在不同溶剂下的反应自由能或活化自由能与溶剂的分子结构之间的关系进行了研究,确证了模型的合理性。     

万能公式的自述

我叫“万能公式” ,由以下三兄弟组成 :ｓｉｎα =2ｔｇ α21 ｔｇ2 α2( 1)ｃｏｓα =1-ｔｇ2 α21 ｔｇ2 α2( 2 )ｔｇα =2ｔｇ α21-ｔｇ2 α2( 3)因为不论α角的哪一种三角函数 ,我都能将它们统一成ｔｇ α2 的有理式 ,这“统一”和“有理”正是我“万能”之根源 ,使我成为沟通三角 ,代数、几何的纽带 ,因此 ,朋友们为我起了一个令我非常满意而自豪的名字———“万能公式” .我也没有辜负大家对我的期望 ,在我的帮助下 ,很多问题被巧妙地解决 .例 1　求函数ｙ =1 ｘ - 2ｘ2 ｘ3 ｘ41 2ｘ2 ｘ4的值域 ?许多同学遇到这类题常感不知…     

压电螺位错与椭圆夹杂的电弹相互作用

研究了压电材料中压电螺位错与椭圆夹杂的电弹相互作用.基于扰动概念和级数展开方法,推导了基体和夹杂的弹性场和电场,在此基础上给出了作用于位错上像力的表达式.通过分析基体与夹杂的相对刚度和机电耦合强弱对像力的影响,得到了新的相互作用机理.     

Dislocation energy and calculation from Peierls stress： a rigorous the lattice theory

In the classical Peierls--Nabarro (P-N) theory of dislocation, there is a long-standing contradiction that the stable configuration of dislocation has maximum energy rather than minimum energy. In this paper, the dislocation energy is calculated rigorously in the context of the full lattice theory. It is found that besides the misfit energy considered in the classical P-N theory, there is an extra elastic strain energy that is also associated with the discreteness of lattice. The contradiction can be automatically removed provided that the elastic strain energy associated with the discreteness is taken into account. This elastic strain energy is very important because its magnitude is larger than the misfit energy, its sign is opposite to the misfit energy. Since the elastic strain energy and misfit energy associated with discreteness cancel each other, and the width of dislocation becomes wide in the lattice theory, the Peierls energy, which measures the height of the effective potential barrier, becomes much smaller than that given in the classical P-N theory. The results calculated here agree with experimental data. Furthermore, based on the results obtained, a useful formula of the Peierls stress is proposed to fully include the discreteness effects.     

Anchoring properties of substrate with a grating surface

The anchoring properties of substrate with a grating surface are investigated analytically. The alignment of nematic liquid crystal (NLC) in a grating surface originates from two mechanisms, thus the anchoring energy consists of two parts. One originates from the interaction potential between NLC molecules and the molecules on the substrate surface, and the other stems from the increased elastic strain energy. Based on the two mechanisms, the expression of anchoring energy per unit area of a projected plane of this grating surface is deduced and called the equivalent anchoring energy formula. Both the strength and the easy direction of equivalent anchoring energy are a function of the geometrical parameters (amplitude and pitch) of a grating surface. By using this formula, the grating surface can be replaced by its projected plane and its anchoring properties can be described by the equivalent anchoring energy formula.     

Studies on heteronuclear diatomic molecular dissociation energies using algebraic energy method

The algebraic energy method (AEM) is applied to the study of molecular dissociation energy $D_e$ for 11 heteronuclear diatomic electronic states: $a^3\Sigma^+$ state of NaK, $X^2\Sigma^+$ state of XeBr, $X^2\Sigma^+$ state of HgI, $X^1\Sigma^+$ state of LiH, $A^3\Pi(1)$ state of ICl, $X^1\Sigma^+$ state of CsH, $A(^3\Pi_1)$ and $B0^+(^3\Pi)$ states of ClF, $2^1\Pi$ state of KRb, $X^1\Sigma^+$ state of CO, and $c^3\Sigma^+$ state of NaK molecule. The results show that the values of $D_e$ computed by using the AEM are satisfactorily accurate compared with experimental ones. The AEM can serve as an economic and useful tool to generate a reliable $D_e$ within an allowed experimental error for the electronic states whose molecular dissociation energies are unavailable from the existing literature.     

BNBT无铅压电陶瓷晶粒定向生长

采用固相合成法制备了0.94(Na1/2 Bi1/2)TiO3-0.06BaTiO3(BNBT)陶瓷粉体,用传统压电陶瓷工艺制备了无铅压电陶瓷,研究了烧结工艺对其径向收缩率和相对密度的影响.结果表明:随着保温时间的增加,径向收缩率和相对密度都出现了极大值.将陶瓷粉体与分散剂均匀混合制成高固相含量的浆料,以SrTiO3(100)单晶基片做模板,通过流延法制备了晶粒定向生长模型材料,初步探讨了热处理工艺对晶粒定向生长习性的影响.结果表明,随着保温时间的增加,晶体生长层厚度增加,生长层致密度增大.     

具有初应力的1-3型压电复合材料的横向共振分析

1-3型压电复合材料在极化处理过程中会出现极化残余应力,基于线性压电理论,采用解析方法研究了极化残余应力对1-3型压电复合材料的横向共振模态的影响．首先建立含有初始应力的平面波波动方程,基于Bloch波函数理论构建了位移和电势函数,从而最终得到方程的解．数值结果表明初始残余应力的出现降低了复合材料的横向振动频率,而材料的压电性则使得横向振动频率提高．初始剪应力对对横向振动的频率影响较小,可以忽略．第一阶及第二阶振动频率将随着初始应力的大小呈线性变化．得出的结论对超声换能器的制作和研究将提供有意义的指导作用．     

压电材料中两个非对称平行裂纹的基本解

采用Schmidt方法分析压电材料中非对称平行的双可导通裂纹的断裂性能．利用Fourier变换使问题的求解转换为求解两对以裂纹面位移之差为未知变量的对偶积分方程．为了求解对偶积分方程,直接把裂纹面位移差函数展开成Jacobi多项式形式．最终得到了裂纹的应力强度因子与电位移强度因子之间的关系．数值结果表明,应力强度因子和电位移强度因子与裂纹间的距离、裂纹的几何尺寸有关;与不可导通裂纹有关结果相比,可导通裂纹的电位移强度因子远小于相应问题不可导通裂纹的电位移强度因子．同时可以发现裂纹间的“屏蔽”效应也在压电材料中出现．