500kV MOA现场试验直流发生器过流保护动作原因分析

500kV主变高压侧MOA做直流泄漏电流试验时,如遇有相同电压等级变压器在其邻近运行,由于该变压器的输入架空导线和相应电气设备临近预试避雷器的边相,使预试MOA边相均压环处的感应电压较高,虽然操作人员注意了直流发生器的升压速度,但有时还会发生直流发生器过流保护动作。弄清直流发生器过流保护动作原因,可避免因判断上的失误而带来检修、试验工作量的增加,即节省检修、试验时间。又可提高变压器设备单元的可用率。

带过流保护的剩余电流动作断路器误接线分析

带过流保护的剩余电流动作断路器是防止触电事故和电气火灾的重要保护装置,安装时的误接线会使之难于投运或发生莫名其妙的跳闸。试从原理入手并结合相关规范,对带过流保护的剩余电流动作断路器误接线进行分析。

一种基于历史路径的工作流实例迁移方法

工作流变更中一个重要问题就是工作流实例的迁移问题。该文根据工作流实例执行的历史路径和节点路由表提出了一个新的迁移策略,减少了一些不必要的回滚和迁移,并对每个节点都确定了相应了迁移动作。

220kV主变跳闸及35kV母线失压事故分析及防范措施

本文介绍某220kV变电站2号主变第一、二套接地变零序过流保护动作,导致2号主变跳闸;35kV二/三段分段自切后加速动作,自切动作不成功,导致35kV三段母线失压。分析继电保护装置动作情况及一次设备检查情况,制定相应反事故措施及注意事项,减少类似事件的发生。

舞蹈审美创造阐述

审美创造作为一切艺术的特征,也是舞蹈艺术的精髓所在。如何创造出真正能给人以艺术吸引力、感染力的舞蹈作品,如何把握舞蹈艺术中的审美创造思维?笔者认为,可以从动作流的传情达意,“形神化”的意外之象,“诗情感”的气韵涌随三方面的来把握。

有关篮球组合技术的研究

对有关篮球组合技术的研究，做了文献综述。

舞蹈艺术的审美特性

一、"动作流"——舞蹈创造美的特有手段舞蹈是以人体为媒介的艺术,人体的动作姿态是舞蹈艺术的最基本的元素,在舞蹈艺术中,表演者、表现手段和创作成果是三位一体的,都是人体本身。舞蹈艺术的美是在动作流中展现的人体的姿态节律的美,诸如形体美、造型美、技巧美及情绪美等等。

Dynamic hierarchy description and constraint rules of flexibility workflow

A dynamic hierarchical description method for workflow is presented. The method provides a dynamic hierarchical way to define a workflow with non-determinate or dynamic factors. With this method, the main process defined at build-time can be reified and extended by the principle of the sub-organizations at either the build-time or the run-time. To ensure the consistency and integrity of the description, a series of constraint rules are also discussed to realize seamless integration between a decomposed process and its original one. This approach supports the description of unpredictable uncertainties, the dynamic hierarchy of business process, and the dynamic modification of enterprise organizations, and all of these improve the flexibility and extendability of workflow management systems dramatically.

Mechanisms of Cyclovirobuxine D on APD Prolongation in Rat Ventricular Myocytes

Aim To study the effects of cyclovirobuxine D on inward rectifier K^- current(I_(k1) ) > transient outward K^+ current (I_(to)), L-type Ca^(2+) current (I_(Ca-L)), and actionpotential duration (APD) in isolated rat ventricular myocytes. Methods The whole cell patch-clamptechniques were used to study the changes of I_(k1), I_(to), I_(Ca-L) and APD in rat ventricularmyocytes. Results Cyclovirobuxine D (1-10 μmol·L^(-1)) significantly prolonged APD_(50) andAPD_(90) in isolated rat ventricular myocytes. Resting potential (RP) was decreased by 10μmol·L^(-1) of cyclovirobuxine D. Cyclovirobuxine D significantly decreased both inward andoutward components of I_(k1) . At - 100 mV, 1 and 10 μmol·L^(-1) of cyclovirobuxine D decreasedI_(k1), density from (-8.0+- 1.1) pA/pF to ( - 4.1 +- 0.7) pA/pF and ( - 3.4 +- 0.8) pA/pF,respectively, whereas at - 30 mV, I-(k1) density was decreased from (1.10 +-0.24) pA/pF to (0.61+-0.18) pA/pF and (0.36+- 0.11) pA/pF, respectively. 1_(to) was markedly inhibited bycyclovirobuxine D from the test potential of 0 mV to + 60 mV. At + 40 mV, 1 and 10μmol·L^(-1) ofcyclovirobuxine D decreased I_(to) density from (8.9+- 2.0) pA/pF to (5.5 +- 1.2) pA/pF and (4.9+-0.9) pA/pF, respectively. Cyclovirobuxine D inhibited I_(Ca-L) in a concentration-dependentmanner. At 10 mV, 1 and 10μmol·L^(-1) of cyclovirobuxine D decreased I_(Ca-L) density from ( - 9.9+- 1.8) pA/pF to ( - 6.4 +- 1.4) pA/pF and (-4.2+-0.6) pA/pF, respectively. ConclusionCyclovirobuxine D significantly prolonged APD and inhibited I_(k1), I_(to), and I_(Ca-L) in ratventricular myocytes. The inhibitory effects of cyclovirobuxine D on _(k1) and I_(to) are majormolecular mechanisms of APD prolongation in rat.

一种古老的琉球功夫——连续斩

在很多有名的武师眼中,斯德·坎培尔是个令人尊敬的名字。1962年,他开始求学于琉球小林流空手道学校,不到两年的工夫就得到了黑带。1966年以后,他在加拿大的奥克兰办了一所武术学校。据估计,到目前为止,他已经培养了850多名一流的武术高手。最近,当斯德·坎培尔九段希望我们写一些东西来宣传连续斩功夫——一种几乎被遗忘的琉球功夫时,黑带编辑部的人员采访了他。下面就是采访的结果。——编者黑带:连续斩是什么样的一种功夫?为什么说它对人们的自卫非常重要?坎培尔:连续斩就是连续用拳头进行攻击。它是一种按照一定次序精心编排的空手搏斗功夫。在这种功夫中。

制暴招式精述(三)

一套好的拳术形式应当是攻防兼备、动作流畅、动静结合、气意神随,其内容应当包容基本动作、基本打法、基本步法、基本手型、基本身法等。下面与广大读者一起分享制暴十六式的9-12式。这一套拳术,容基本拳法、腿法、肘法、

制暴招式精述(四)

一套好的拳术形式应当是攻防兼备、动作流畅、动静结合、气意神随,其内容应当包容基本动作、基本打法、基本步法、基本手型、基本身法等。下面与广大读者一起分享制暴十六式的13-16式。

制暴招式精述(一)

一套好的拳术形式应当是攻防兼备、动作流畅、动静结合、气意神随,其内容应当包容基本动作、基本打法、基本步法、基本手型、基本身法等。

制暴招式精述(二)

一套好的拳术形式应当是攻防兼备、动作流畅、动静结合、气意神随,其内容应当包容基本动作、基本打法、基本步法、基本手型、基本身法等。下面与广大读者一起分享制暴十六式的5-8式。这一套拳术,容基本拳法、腿法、肘法、膝法于一体。

Heat Transfer Between Immersed Horizontal Tubes and Aerated Vibrated Fluidized Beds

Heat transfer coefficients between an immersed horizontal tube and an aerated vibrated fluidized bed are measured. There is a maximum value in the h-P experimental curve. The heat transfer coefficient increases with decreases in particle diameter in the fully fluidized region. The particle density has less effect on the heat transfer coefficients. High amplitude and low frequency, or low amplitude and high frequency are favorable to heat transfer. Exceedingly high gas velocity is unfavorable to the surface-bed heat transfer. A model based on the 'pocket' theory was proposed for predicting the surface-to-bed heat transfer coefficients in fully fluidized region. The predictions from the model were compared with observed data. The reasonable fit suggests the adequacy of the model.

Characterization of a Chinese KCNQ1 mutation （R259H） that shortens repolarization and causes short QT syndrome 2

Objectives To evaluate the association between a KCNQ 1 mutation, R259H, and short QT syndrome （SQTS） and to explore the elec- trophysiological mechanisms underlying their association. Methods We performed genetic screening of SQTS genes in 25 probands and their family members （63 patients）. We used direct sequencing to screen the exons and intron-exon boundaries of candidate genes that en- code ion channels which contribute to the repolarization of the ventricular action potential, including KCNQI, KCNH2, KCNE1, KCNE2, KCNJ2, CACNAlc, CACNB2b and CACNA2D1. In one of the 25 SQTS probands screened, we discovered a KCNQ1 mutation, R259H. We cloned R259H and transiently expressed it in HEK-293 cells; then, currents were recorded using whole cell patch clamp techniques. Results R259H-KCNQ 1 showed significantly increased current density, which was approximately 3-fold larger than that of wild type （WT） after a depolarizing pulse at 1 s. The steady state voltage dependence of the activation and inactivation did not show significant differences between the WT and R259H mutation （P 〉 0.05）, whereas the time constant of deactivation was markedly prolonged in the mutant compared with the WT in terms of the test potentials, which indicated that the deactivation of R259H was markedly slower than that of the WT. These results suggested that the R259H mutation can effectively increase the slowly activated delayed rectifier potassium current （Irs） in phase 3 of the cardiac action potential, which may be an infrequent cause of QT interval shortening. Conclusions R259H is a gain-of-function muta- tion of the KCNQ1 channel that is responsible for SQTS2. This is the first time that the R259H mutation was detected in Chinese people.

Flow behaviour constitutive model of CuCrZr alloy and 35CrMo steel based on dynamic recrystallization softening effect under elevated temperature

In order to study the effect of dynamic recrystallization on the metal flow behavior during thermal deformation,the elevated temperature compression experiments of CuCrZr alloy and 35CrMo steel are carried out using Gleeble-3810 thermal simulator.It is proved that the samples underwent obvious dynamic recrystallization behavior during thermal deformation by microstructure observation of deformed specimens.The size of recrystallized grains increases as the temperature improved and the strain rate decreased.Meanwhile,the net softening rate caused by dynamic recrystallization is determined based on the stress-dislocation relationship.It can be found that the value of net softening rate increases quadratically as the Z parameter decreases,and the dynamic recrystallization net softening rate of CuCrZr alloy and 35CrMo steel are calculated to be 21.9%and 29.8%,respectively.Based on the dynamic recrystallization softening effect proposed,the novel elevated temperature flow constitutive models of two different alloys are proposed,and the related parameters are well defined and solved in detail.The predicted values of the obtained models are agreed well with the experimental values.

Analysis of the wave propagation and the flow char-acteristics around cylinder due to dam break water

Dam breaks are easily triggered by heavy rains due to extreme weather such as typhoons,causing serious economic losses and casualties.Through the investigation of Chaoshan coastal zone,it is found that there have been dam breaks caused by geological disasters.In the design and management of water conservancy project,it is very important to analyze the effect of disastrous flow caused by dam break on the building.In this paper,the effect of the dam break flow on the cylinder is simulated numerically by taking the water body with initial velocity as the dam break flow,and the flow characteristics around the cylinder and the water body are analyzed.Numerical model adopted the Renault Average Navier-Stokes(RANS)model and volume of fluid(VOF)method to analyze the evolution of free water surface.It is found that there are different patterns of water movement in the process of dam break resulting in the creation of several isolated convex hull forms of dam-break waves on the stationary water surface,which causes longer disturbances in the water near the cylinder and makes the cylinder more vulnerable to fatigue damage.The increase of the height of the dam breaking water will lead to the increase of the hydrodynamic force on the pipeline.This study has guiding significance for the study of dam break and dam body design in water conservancy projects.

Analysis of Pseudomomentum Wave-Activity Density in a Heavy Rainfall Event in East China

Taking into account moisture in virtue of general potential temperature,the author derive a three-dimensional(3D) pseudomomentum wave-activity relation for the moist atmosphere from the primitive equations in Cartesian coordinates using the Momentum-Casimir method.Since the wave-activity relation is constructed in an ageostrophic and non-hydrostatic dynamical framework,it may be applicable to diagnosing the evolution and propagation of mesoscale systems leading to heavy rainfall.The theoretical analysis shows that,besides the local change of wave-activity flux divergence and source or sink,the wave-activity relation includes two additional forcing terms.The first is the zonal gradient of difference between general potential temperature and potential temperature perturbations,and the second is the covariance of the solenoid and gradient of water vapor,denoting the direct influence of moisture on wave-activity density.The wave-activity density was applied to a heavy precipitation event occurring in the Jianghuai region of China.The calculation showed that the wave-activity density was consistent with 6-h accumulated precipitation observations,in terms of both spatial distribution and temporal tendency.This suggested that the disturbance represented by wave-activity density was closely related to the heavy precipitation.Although the wave-activity flux divergence and the covariance of the solenoid and gradient of water vapor made the primary contribution to the local change of wave-activity density,the covariance was more remarkable.The zonal gradient of difference between general potential temperature and potential temperature perturbations made a weaker contribution to the waveactivity density.