The onset of formation of the water liquid phase in pores of carbon adsorbents

A two-stage mechanism of adsorption, including nucleation and condensation, was proposed to describe the formation of the water liquid phase in carbon adsorbents. Adsorption is assumed to occur in cylindrical pores. Nucleation is described by a modified BET model, and condensation is treated by the model of a stretched liquid film on a bent surface. The onset of formation of the liquid phase (OFLP) is determined from the intersection of the adsorption isotherms for these stages. The theoretical value of the relative pressure of OFLP varies over a wide range, decreasing with a decrease in the pore radius and reactiing the relative vapor pressure of 0.178 for the spinodal state of water. The comparison method using isotherms of graphitized carbon black as the reference isotherms was applied for the determination of OFLP of water in real active carbons. This resulted in good agreement between theory and experiment. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 668–671, April, 1999.     

硅熔体CZ结构浅池内热毛细对流转变滞后特性

为了了解水平温度梯度作用时Czochralski(CZ)结构浅池内硅熔体热毛细对流的转变滞后特性,利用有限差分法进行了非稳态三维数值模拟,坩埚外壁被加热,半径为50mm,晶体半径为15mm,液池深度为3mm,坩埚外壁与晶体生长界面温差变化范围为6-27K。模拟结果表明,当逐渐增加温差时,在△T=9K处,二维轴对称流动转变为三维稳态流动,在△T=20.6K处,三维稳态流动转变为三维振荡流动;当逐渐减小温差时,在△T=19.5K处,三维振荡流动才转变为三维稳态流动,因此,二次流动转变存在滞后,滞后温差约为1.1K。     

滞环SVPWM整流器的Simulink仿真

针对目前电流滞环控制存在的缺点,提出了一种基于不定频滞环的空间矢量脉宽调制(SVPWM)电流控制方法,这类控制方案将滞环控制与SVPWM控制有机地结合起来,在取得快速电流响应的同时,降低了开关频率,提高了系统运行效率.本文介绍了基于不定频滞环的SVPWM电流控制原理,并用Simulink模块库建立了仿真模型,仿真结果表明了该控制策略的可行性.     

磁性多层膜的磁滞回线和磁阻曲线的唯像理论研究

基于相干转动的局域能量极小模型和经典的热激活模型研究了包含二次、双二次耦合的磁性多层膜的磁化过程。计算结果表明双二次耦合和磁层的层数对多层膜的磁相图、磁滞回线、磁阻曲线都有重要的影响。在有限温度下，热激活使得磁性多层膜的磁状态间发生跳跃而达到动态平衡。当引入了具有高斯分布的微磁畴元后，计算了系统的磁状态，得到了不同温度下的磁滞回线和磁阻曲线。计算结果较好地解释了形态各异的磁滞回线和磁阻曲线。     

Magnetic Alignment in Solid State and Temperature Hysteresis in Aqueous Tetrahydrofuran Solution for Tetrathiafulvaleno[18]annulenes

Tris(tetrathiafulvaleno)dodecadehydro[18]annulene‐hexaesters have a multi‐functionality that is very sensitive to small differences in the ester side‐chain. Self‐aggregation of the [18]annulenes in amphiphilic media such as THF–H₂O (v/v, 1:1) either produce a fibrous structure or result in temperature hysteresis of the color and ¹H NMR signals. This temperature hysteresis in solution is due to both strong self‐aggregation behavior and unique cluster formation in a binary solution of THF and water.     

用瞬态波形存贮器统一直流、交流、脉冲磁性的测量

对用瞬态波形存贮器统一直流、交流、脉冲磁性测量进行了试验、分析 给出测量一般原理 ,并测量了直流、脉冲退磁曲线 ,交流磁滞回线 将直流、交流测量和传统的方法进行比较 ,对脉冲测量进行定量计算 ,并讨论了误差及引起误差的原因 对测量中遇到的问题以及解决方法 ,作了说明 结果证明文中方法是可行的 ,但一些技术性细节问题还有待改进 ,从而进一步完善此方法     

On a model for electromagnetic processes inside and outside a ferromagnetic body

One‐dimensional Maxwell's equations are considered in a ferromagnetic body surrounded by vacuum. Existence and uniqueness of solution for the resulting system of partial differential equations with hysteresis on the whole real line is proved under suitable constitutive hypotheses. Copyright © 2008 John Wiley & Sons, Ltd.     

Estimation of the minimum pore size sufficient for capillary hysteresis

A procedure for determination of the minimum pore sizes suitable for the formation of an adsorption-desorption hysteresis loop was developed. Conditions for the formation of hysteresis in infinite rectangular channels and in the cavities restricted along three directions (spheres, rectangular parallelepipeds) and in channels with different cross-sections and limited lengths are considered. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 18–28, January, 2008.     

无热滞新型恒温水浴的研制

采用第二类导体作为发热体兼做传热介质,设计出一种有别于传统恒温装置的新型恒温器.和常规恒温装置比较,论述了其基本构造和工作原理,探讨了影响控温灵敏度的几个因素.结果表明,当以Pt100热敏电阻为感温元件,LU—902K型位式调节仪作为温度控制器时,可使控温灵敏度达到±0.02℃.