Electromechanical coupled nonlinear dynamics for microbeams

In this paper, an electromechanical coupled nonlinear dynamic equation of a microbeam under an electrostatic force is presented. Using the nonlinear dynamic equations and perturbation method, we investigated nonlinear free vibrations, forced responses far from and near to natural frequency, respectively. Nonlinear natural frequencies and vibrating amplitudes of the electromechanical coupled microbeam are dependent on the mechanical and electric parameters. Compared with linear forced responses, the obvious shift of the mean dynamic response occurs. Under certain condition, the jump phenomenon will occur. The studies can be used to design parameters of the microbeam and remove undesirable dynamic behavior such as jump phenomenon, etc.     

Improved adaptive-threshold burst assembly in optical burst switching networks

An improved adaptive-threshold burst assembly algorithm is proposed to alleviate the limitation of conventional assembly schemes on data loss and delay. The algorithm will adjust the values of assembly factors according to variant traffic regions. And the simulation results show that, by using the adaptive-factor adaptive assembly scheme, the performance of networks is extensively enhanced in terms of burst loss probability and average queuing delay.     

一种维修性神经网络模型

运用神经网络的ＢＰ算法建立了系统的维修性模型，结合一实例验证了模型，效果较好。     

南蛇藤中倍半萜生物碱的二维NMR研究

用DEPT和二维NMR技术包括:¹H-¹H COSY,¹H-¹³C COSY,NOESY,特别是¹H-¹³C COLOC对两个多酯基取代的倍半萜生物碱的化学及立体结构进行了研究,并对其¹H和¹³C NMR谱峰进行了归属。     

飞秒激光烧蚀石英玻璃的实验与理论研究

实验研究了800nm飞秒激光作用下石英玻璃的破坏机理和烧蚀规律，给出了破坏阈值与脉冲宽度的关系.发展了雪崩击穿模型，计算了材料的烧蚀阈值与脉冲宽度的依赖关系，烧蚀深度、烧蚀体积与脉冲能量的依赖关系，研究了导带电子的扩散对材料中激光能量的沉积、分布，以及材料的破坏阈值和烧蚀规律的影响. 关键词： 飞秒激光脉冲 破坏机理 石英玻璃 电子扩散     

A study of irradiation in the treatment of wastewater

A grafting copolymer of starch and acrylamide was prepared by ⁶⁰Co-γ pre-irradiation. After purification, the copolymer was modified by a cationic reaction to form a cationic copolymer. The structure of the cationic copolymer was identified by IR and NMR spectroscopy. Using the industrial and sanitary municipal wastewater from the Factory of Wastewater Treatment of Gaobeidian in Beijing as the study sample, three-treatment methods: flocculation deposition, flocculation deposition combined with γ irradiation and the direct irradiation were carried out. COD was applied to evaluate the treatment effect. The preliminary results show that the method of flocculation deposition combined with γ irradiation was effective than the other two.     

量化计算在二芳基二硫代膦酸结构和光谱分析中的应用

在拉曼和红外光谱分析中，谱峰的归属直接关系到对分子结构的判定。本工作以量子化学理论计算为基础，探索对二芳基二硫代磷酸实验拉曼谱图进行谱峰归属的可行性。结果表明：二芳基二硫代膦酸理论计算谱图与实验谱图具有相关性，理论计算谱图可以指导实验谱图谱峰的归属分析。     

二维晶格上Kadanoff分块及重整化群方法

对二维晶格上的Kadanoff分块进行了全面分析，给出了划分的一般规律，得出元块选择的非任意性和含相同元块选择不惟一等结论，并给出正三角形格子和正方形格子元块中格点数目的允许值。同时，利用重整化群方法对9点，13点元块进行了计算，得到了相应的不动点和各种临界指数，并与其它计算结果进行了比较，结果表明，计算精度有随元块中所含格点数的增加而增加的趋势。     

光度法测定水中溴化十六烷基三甲铵

研究采用光度法,在pH5.0的缓冲溶液中,2 羟基 5 磺苯偶氮苯亚甲基肼基 2′ 羟基苯(R)与溴化十六烷基三甲铵(CTMAB)相互作用,当向R中加入CTMAB,立即生成红色配合物,其最大吸收峰为540和570nm;摩尔吸光系数ε=2.2×104L·mol-1·cm-1。由此建立了高灵敏度的吸光光度法测定水中微量的CTMAB。试验了该体系的酸度、温度、时间、浓度等最佳反应条件。在0.005×10-5～2.2×10-5mol·L-1浓度范围内呈良好的线性关系。检出限为1μg·ml-1。     

Improvements of n-dimensional Euler inequality

In this paper, a new upper bound for the volume of an n-dimensional simplex is given, which improves some previous results stated in [2] and [4].