On the structure of continua and the mathematical properties of algebraic elastodynamic of a triclinic structural system

This paper is neither laudatory nor derogatory but it simply contrasts with what might be called elastostatic (or static topology), a proposition of the famous six equations. The extension strains and the shearing strains which were derived by A.L. Cauchy, are linearly expressed in terms of nine partial derivatives of the displacement function (u _i ,u _j ,u _h )=u(x ⁱ ,x ^j ,x ^k ) and it is impossible for the inverse proposition to sep up a system of the above six equations in expressing the nine components of matrix (∂(u _i ,u _j ,u _h )/∂(x ⁱ ,x ^j ,x ^k )). This is due to the fact that our geometrical representations of deformation at a given point are as yet incomplete^[1]. On the other hand, in more geometrical language this theorem is not true to any triangle, except orthogonal, for “squared length” in space^[2]. The purpose of this paper is to describe some mathematic laws of algebraic elastodynamics and the relationships between the above-mentioned important questions.     

THE BOUNDARY ELEMENT METHOD (BEM) FOR WAVE EQUATION

The formula of BEM suited to solve the problems of wave propagation in boundlessmedium is obtained from numerical treatment of Kirchhoff integral equation.Afer quotingthe coefficients of refraction and reflection of wave at surface or interface,the expression ofBEM which is suitable for the problems of wave propagation in multi-isotropic mediums isalso given.     

两种不锈钢在高压下的状态方程

 测定了两种不锈钢在室温下、4.5 GPa内的p-V关系，并给出了它们的Bridgman方程。根据Bridgman方程的系数a和b，计算了它们的格临爱森参数γ₀、体积模量B₀和B₀的压力导数B₀'。     

准一维聚合物中的声学极化子

本文讨论准一维聚合物中的一维电子通过形变势与三维声学声子相互作用,对弱耦合和中间耦合情形,导出了极化子基态能量和有效质量。结果表明,在这种混合维数模型中,可形成稳定的极化子。     

一种基于数字全息技术的盲音频水印算法

提出了一种基于数字全息技术的盲音频水印算法.水印图像经随机相位调制形成物光波,该物光波的傅里叶变换与参考光波发生干涉,形成傅里叶变换全息图.再利用离散余弦变换的能量压缩能力,通过量化算法把降维的水印,即傅里叶变换全息图嵌入音频信号中,在水印提取过程中不需要原始音频信号的参与.仿真实验表明,该算法对低通滤波、噪音干扰特别是剪裁具有一定的稳健性.     

On-line matrix addition for detecting aerosol particles

Single aerosol particles were measured by matrix-assisted laser desorption/ionization (MALDI) with an aerosol time-of-flight mass spectrometer (ATOFMS). The inlet to the ATOFMS was coupled with an evaporation/condensation flow cell that allowed matrix addition by condensation onto the particles. The coated particles entered the ion source through three-stage differentially pumped capillary inlet and were then ionized by a focused 266 nm Nd:YAG laser. The mass spectra and aerodynamic size of the single particles can be obtained simultaneously. The on-line matrix addition technique makes it possible to identify biological aerosols in real-time.     

Gas source MBE grown wavelength extended 2.2 and 2.5 μm InGaAs PIN photodetectors

Using homo-junction structure and relative thin linear graded In_xGa_1−xAs as the buffer layer, extended wavelength InGaAs PIN photodetectors with cut-off wavelength of 2.2 and 2.5 μm at room temperature have been grown by using GSMBE, and their performance over a wide temperature range have been extensively investigated. For those 2.2 or 2.5 μm detectors with 100 μm diameter, the typical dark current (V_R = 10 mV) and R₀A are 57 nA/10.3 Ω cm² or 67 nA/12.7 Ω cm² at 290 K, and 84 pA/4.70 kΩ cm² or 161 pA/3.12 kΩ cm² at 210 K respectively. The thermal activation energies of the dark current are 0.447 eV or 0.404 eV for 2.2 or 2.5 μm detectors respectively.     

脉冲激光偏振方向对氮分子高次谐波的影响——基于含时密度泛函理论的模拟

采用含时密度泛函方法,结合赝势模型和电子交换相关作用的广义梯度近似,模拟了氮分子在超强飞秒激光脉冲作用下的高次谐波产生现象,并研究了激光脉冲偏振方向对氮分子高次谐波的影响.结果表明氮分子的高次谐波谱具有典型原子谐波谱的特征;谐波谱强度随着θ(激光偏振方向与分子轴向夹角)的增大而减小.这与J.Itatanl在Nature上报道的实验结果基本一致.     

SiO2-羟基表面上金属原子的第一性原理研究

采用第一性原理方法研究了SiO2-羟基表面上几种金属原子的吸附性质,发现In和Ga在SiO2-羟基表面上的结合很弱,而Fe,Co,Ni在该表面上与Si,O形成强的化学键.等势能面和扩散势垒计算表明In(Ga)的扩散激活能只有0.1-0.3 eV,表明这两种原子容易在表面上扩散.这些结果可以定性地解释纳米合成中的一些实验现象.