0.5级电子式电能表的设计与实现

本文论述了一种普及型电子式电能表的设计原理和实现方法，具体讨论了时分割乘法器和电流互感器的组成和误差分析，最后给出测试结果。     

Sensitivity analysis of free torsional vibration frequencies of thin-walled i-beam resting on elastic foundation

The sensitivity analysis of natural frequencies of torsional vibration of thin-walled I-beams resting on a Winkler-type elastic foundation and subjected to axial static loads is discussed. The first-order variation of the frequencies due to the design variable variations is derived. The cross- ection dimensions, the beam material constants and the foundation stiffness are assumed to be the design variables. The considerations are based on the theory of thin-walled beams with nondeformable cross-section. The underintegral sensitivity coefficients of the flange width and the foundation stiffness variations for a simply supported I-beam are determined. An accuracy of approximation of the natural frequencies changes due to the design variable change, by means of their first-order variations, is also investigated.     

塔河油田特殊钻井条件下的录井技术

该文阐述了定向井、水平井和欠平衡钻井技术对传统录井方法的影响:钻时偏大、失真,岩屑细、代表性差,荧光常达12级、无意义,全烃值一般在5%以上,难以有效划分油气层;指出在特殊钻井条件下掌握设计指导思想,卡准重要层位是录井工作的关键,重点要参考组分分析数据、定量荧光分析数据和综合录井其它信息才能准确识别油气层。     

光隔离器及其相关的磁光材料

本文简要介绍了磁光隔离器的理论、结构和分类 ,并提出了该器件今后发展的几个问题 ,最后介绍了几种磁光材料     

偏振模色散统计特性的研究

利用动态方程研究了偏振模色散矢量的统计特性 ,分别用统计系综和频率系综两种方法进行数值模拟。数值结果表明 ,统计系综和频率系综两种方法的结果一致。在大归一化距离条件下 ,均方根时延的平方随归一化距离线性变化 ;偏振模色散矢量的各个分量服从高斯分布 ,差分群时延服从麦克斯韦分布 ;偏振模色散矢量弥散于整个邦加球     

Pad effects on material-removal rate in chemical-mechanical planarization

The role of a porous pad in controlling material-removal rate (MRR) during the chemical-mechanical planarization (CMP) process has been studied numerically. The numerical results are used to develop a phenomenological model that correlates the forces on each individual abrasive particle to the applied nominal pressure. The model provides a physical explanation for the experimentally observed domains of pressure-dependent MRR, where the pad deformation controls the load sharing between active-abrasive particles and direct pad-wafer contact. The predicted correlations between MRR and slurry characteristics, i.e., particle size and concentration, are in agreement with experimentally measured trends reported by Ouma¹ and Izumitani.²     

中国台湾电信市场现状

台湾电信市场的开放大致分四个阶段,从1995年起,陆续开放了移动通信、卫星通信及固定通信等多种业务。固网市场,2001年新世纪资通、台湾固网和力霸宽频电信的加入打破了中华电信的独家垄断,开始形成四强竞争的新局面。移动领域,1997年底6家运营商8张民营执照的发放开始了该领域史无前例的竞争。在2001年1月,台湾大哥大、远致电信、亚太行动宽频、联邦电信和中华电信获得了3G执照,累计竞标金额达488.99亿元(新台币)。     

OSEK/VDX——汽车电子系统的开放式平台

介绍了当前在国际汽车工业界日益占据主导地位的汽车电子系统开放式平台--OSEK/VDX体系.详细地论述了这种体系的由来、运行机制和最新的发展动向,以及它对汽车电子技术发展的深远影响.     

A new family of yeast genes implicated in ergosterol synthesis is related to the human oxysterol binding protein

We have identified three yeast genes, KES1, HES1 and OSH1, whose products show homology to the human oxysterol binding protein (OSBP). Mutations in these genes resulted in pleiotropic sterol-related phenotypes. These include tryptophan-transport defects and nystatin resistance, shown by double and triple mutants. In addition, mutant combinations showed small but apparently cumulative reductions in membrane ergosterol levels. The three yeast genes are also functionally related as overexpression of HES1 or KES1 alleviated the tryptophan-transport defect in kes1Δ or osh1Δ mutants, respectively. Our study implicates this new yeast gene family in ergosterol synthesis and provides comparative evidence of a role for human OSBP in cholesterol synthesis.