An investigation of induced voltages to an underground gas pipeline from an overhead transmission line

This paper investigates induced voltage characteristics from an overhead transmission line by applying a method of modeling of induced voltages proposed by the authors. EMTP simulation results obtained by the modeling method agree with analytical results obtained from a well‐known formula. The induced voltages are significantly dependent on the configuration of the overhead line. A horizontal line induces the largest voltage in a gas pipeline, and the voltage induced by a vertical twin‐circuit line is about 20% smaller than that induced by a vertical single‐circuit line. The method is applied to a real pipeline system and the simulation results show reasonable agreement with field test results. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(1): 43–51, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20465     

胃动力信息采集与分析系统设计

本文设计了一套提取胃电和胃阻抗信号的胃动力信息采集与分析系统，该系统由采集系统和分析系统两部分构成。前者以单片机（ADuC834）为核心部件，实现了胃电和生物阻抗信号的同步采集和数据传输。后者对提取的阻抗信号和胃电信号运用小波多分辨分析处理，利用小波变换将胃阻抗信号从呼吸和血流信号中分离。系统可以应用于分析功能性消化不良患者胃动力的电过程和机械过程。     

PV module dynamic impedance and its voltage and frequency dependencies

The paper presents a derivation of the dynamic impedance of a PV module. At each bias voltage, the general form of the impedance describes a semicircular locus in the complex impedance plane. Intercepts of each impedance locus yield series, shunt and dynamic resistance of a module. Determinations of the dynamic impedance of a x-Si PV module in the dark with five reverse bias voltages and over a frequency range of 1 Hz to 60 kHz are made. The experimental results validate the derived general form of dynamic impedance.     

Streaming potential measurements on stainless steels surfaces: evidence of a gel-like layer at the steel/electrolyte interface

Electric charges at the surface of a passive stainless steel are generally considered as concentrated either in the passive film itself, or at the metal/passive film interface, or in the electrical double layer at the film solution interface. Rest potential time dependence after immersion of a passive surface in aqueous electrolytes suggests however that slow processes occur in the onset of the surface charge. Specific experiments, such as streaming potential measurements and electrochemical impedance spectroscopy in a thin electrolyte cell, were carried out for understanding better this phenomenon. An AISI 304 type austenitic stainless steel with polished or bright annealed surface finishes was immersed in NaCl aqueous solutions with various pH and chloride concentrations. The streaming potential time evolution shows two steps: a first rapid one (∼2 min) is attributed to the onset of the surface charge. The second step is much slower (approximately several hours) and possibly due to an interphase layer between the passive film and the solution. Following this idea, the whole kinetics is controlled by cation migration across the interphase when the pH is larger than the isoelectric pH (pH_iep), while chloride ions are incorporated in the interphase when pH < pH_iep. Impedance measurements allow determining both the kinetics of charge transport and the thin cell conductivity. When glass is used as reference material for the cell walls instead of stainless steel, the Nyquist plots show a high-frequency response. For stainless steel cell walls, a low-frequency response is observed, attributed to a slow charge reorganisation inside the interphase layer. The charge distribution at metal/electrolyte interface is discussed in terms of a gel-like layer which possibly takes place at the passive film/electrolyte interface.     

高分辨率测井约束地震反演技术在本布图地区的应用

简要介绍了高分辨率测井约束地震反演技术应遵循的原则及实现步骤,并应用该技术对焉耆盆地本布图背斜构造带进行预测和分析。通过对比分析,反演剖面的分辨率和信噪比有所提高,能较好的反映储层性质的横向变化,预测结果与实际基本符合,说明高分辨率测井约束反演技术在该地区具有一定的实用性。     

PCF的信息系统模型

带类型的λ－演算是一个逻辑系统，它可以作为程序语言的基础．Ｐｌｏｔｋｉｎ所引进的ＰＣＦ就是这样一类程序语言．Ｐｌｏｔｋｉｎ构造了ＰＣＦ的一个模型，然后讨论与这个模型相关的指称语义和操作语义之间的配合问题──简单配合和完全配合．本文利用Ｓｃｏｔｔ引进的信息系统概念构造ＰＣＦ的另一种模型，并证明与这个模型对应的指称语义与操作语义是完全配合的．     

基于模糊匹配的平面连杆机构反求设计研究

对平面连杆机构曲线进行了分析,提出了用一组特征参数来描述连杆曲线,建立了连杆曲线图谱库,并将模糊论应用于连杆机构的曲线匹配,从而获取所求的机构参数.最后给出了应用实例,证实了该方法的可行性与有效性.     

FeSiB薄膜的巨磁阻抗和应力阻抗效应研究

软磁材料中存在巨磁阻抗 (giantmagneto impedance ,GMI)效应以及与之相同来源的应力阻抗 (stress impedance ,SI)效应 ,利用这两种效应可以制成具有高灵敏度的微型化的磁场和应力 应变传感器。本文基于传感器的实际应用 ,对图形化的、较大磁致伸缩的FeSiB单层和多层薄膜的巨磁阻抗和应力阻抗效应中频率和退火的影响进行了研究。结果表明 ,对于两种效应 ,经过退火处理的单层和多层膜均可在较低的频率下得到较高的灵敏度 ,而多层膜中的应力阻抗效应将为新型高灵敏传感器的设计和研制开辟一条崭新的途径     

开滦集团公司煤层间配采模型的建立

运用线性规划建立了数学模型，解决了开栾集团公司煤层间的配采问题，提高了煤炭企业的经济效益，有利于企业实现可持续发展。     

用载文南定理计算感应电机和变压器的特性曲线

感应电机和变压器激磁电路的参数是非线性的.为准确求取它们的特性曲线,需要的计算量很大.应用本文引入的方法可以避免大的计算量又可得到准确的特性曲线.