Photolysis of a methanolic solution of benzyl acetate in low acoustic fields

The influence of low acoustic fields on the photolysis of benzyl acetate in solution was investigated. A change in the contributions of alternative photolysis mechanisms is caused by destruction of solvate shells.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 180–181, January, 1995.This study was financially supported by the Russian Foundation for Basic Research (Project No. 93-02-18102).     

激光拉曼光谱在高分子中的应用

论述了激光拉曼光谱对高分子结构、结晶形态和表征,反应动力学过程和取向的研究,还介绍了纵向声学模、共振、高温高压、光波导和付里叶拉曼光谱在高分子研究中的最新进展。     

A new study of the enzymatic hydrolysis of carboxymethyl cellulose with a bulk acoustic wave sensor

A new bulk acoustic wave (BAW) cellulase sensing technique, which is based on the enzymatic hydrolysis process of sodium carboxymethylcellulose (CMC) by cellulase, was established. The frequency shift curves of BAW sensor indicated that the viscosity of the tested solutions decreased during the hydrolysis process. The hydrolysis rate of CMC by cellulase was calculated from the frequency shift curves. The hydrolysis rate of CMC under different pH conditions at 30°C showed that cellulase had high hydrolysis ability approximately at pH 5.0. Kinetic parameters (the Michaelis constant K_m and the maximum rate V_max) of the process were estimated by using a linear method of Lineweaver–Burk plot. K_m is 1.95±0.25 mg ml⁻¹ and V_max is −(4.25±0.58)×10⁻³ g^1/2 cm^−3/2 cP^1/2 min⁻¹. Also the activation energy (E_a) of the enzymatic hydrolysis, with a value of 51.99±1.26 kJ mol⁻¹, was estimated in this work.     

磨削加工的声发射信号分析

对磨削加工中产生的声发射信号进行了分析,讨论了磨削过程中声发射信号影响因素,指出各种声发射信号与其磨削加工状态与有着良好的对应关系,可以用来对磨削加工过程和磨削质量进行监控。     

一种新型的表面声波阻抗传感器及其在液相体系中的应用

一种新型的表面声波阻抗传感器及其在液相体系中的应用姚守拙，陈康，刘德忠，聂利华（湖南大学化学化工系，长沙，４１００８２）关键词表面声波，阻抗传感器，液相应用表面声波传感器（ＳＡＷＳ）具有较高的灵敏度和检测精度，已广泛应用于气体微量组分分析、色谱检测和...     

Study of Densities, Viscosities and Ultrasonic Speeds of Binary Mixtures Containing 1,2-Dimethoxyethane and an Alkan-l-ol at 298.15 K

The viscosity deviation (Δη), the excess molar volume (V ^E) and the ultrasonic speed (u) have been investigated from viscosity (η) and density (ρ ) measurements of binary liquid mixtures of 1,2-dimethyoxyethane with methanol, ethanol, propan-1-ol, butan-1-ol, pentan-1-ol, hexan-1-ol or octan-1-ol over the entire range of composition at 298.15 K. The excess volumes are negative over the entire range of composition for all of the mixtures with the exception of hexan-1-ol and octan-1-ol. The excess isentropic compressibilities (K _S ^E) and viscosity deviations are negative for all of the mixtures. The magnitudes of the negative values of V ^E decrease with the number of carbon atoms of the alkan-1-ol. The trend of increasing K _S ^E values with the chain length of the alkanol is similar to that observed in the case of V ^E. Graphs of V ^E, Δ η, K _S ^E, Δ u, L _f ^E and Z ^E against composition are presented as a basis for a qualitative discussion of the results.     

动态超声彩色血流图像的计算机仿真

计算机仿真超声彩色血流图像，可以为各种超声彩色血流图像处理方法的性能比较提供有效的信号源．在仿真某一时刻静态超声彩色血流图像的基础上，根据给定的一个心动周期的最大血流速度曲线，计算出血管内的血流速度分布随时间的变化，对一个心动周期划分24时相，仿真出动态超声彩色血流图像。     

超声功率对锡锑合金凝固组织的影响

超声处理是改善金属凝固组织、提高材料力学性能的一种有效方法。该文研究了不同功率的高能超声对锡锑合金凝固过程的影响，分析了高能超声细化凝固组织的机理。随着声声功率的增加，合金组织得到了均匀细化，偏析消除；但功率提高到一定程度，细化作用衰减。     

波阻抗反演技术在孤东地区馆陶组薄储层描述中的应用

根据一维波动方程的拟合迭代法原理 ,给出了求解波阻抗σ(x)的算法。针对孤东地区馆陶组薄储层油藏存在的地层埋深浅、较疏松以及井径变化大泥岩中含有膨化矿物蒙脱石等引起的声波测井速度失真问题 ,采用分段函数法对其进行了校正。将校正后的声波资料进行反演 ,可得到高质量的资料 ,用该校正资料追踪描述的储层与录井结果吻合较好。应用结果表明 ,测井资料在反演中可以补充地震资料缺少的低频和高频分量 ,地震波阻抗反演技术是薄储层描述的有效方法     

基于扩展Kalman滤波的声阵列定位数据融合算法

利用各阵元和目标相对于一中心阵元的几何关系建立目标运动方程，坐标变换方程和声阵列测量方程，并以此建立了声阵列目标定位模型。在此基础上提出了基于扩展Kalman滤波算法的目标定位数据融合算法。通过地面目标和空中目标的计算机仿真表明，本算法能够有效地克服由于智能雷布阵的随机性给智能雷定位数据估计带来的困难，对声阵列定位数据也能进行较好的融合，对提高定位精度有一定效果。