超高压线路潜供电弧电压的频率特性分析

针对潜供电弧状态对超高压线路单相自动重合闸影响的问题，提出了一种基于故障相电压谐波情况的电弧状态判断方法．该方法在分析了一次及二次电弧的特性及不同补偿度下电弧熄灭后系统振荡特性的基础上，通过引入总谐波畸变（THD）来反映故障相电压谐波含量的变化．对不同补偿度的系统运用EMTP进行了仿真，结果表明电弧熄灭后，故障点电压的THD值将显著降低，为利用故障点电压的谐波情况来判断电弧状态提供了依据．     

应急预案框架下地铁防灾标识系统优化

当地铁灾害事故发生后,灾区人员有效利用防灾标识系统进行及时疏散,则是防止和减少伤亡损失的重要措施. 本文对国内外大中型地铁站标识进行了系统的调研,分析了国内地铁防灾标识系统现存的问题. 通过国内外防灾标识系统的比较,提出了优化的建议. 最后对地铁防灾标识系统与应急预案框架系统的关系进行了初步的探讨.     

企业与员工新型绿色关系模式的探讨

当前,企业共同面对着发展循环经济和如何留住优秀人才的新课题.本文在对时代背景进行分析的基础上,引入绿色管理的崭新视角,运用心理契约、平衡积分卡等工具,积极探寻企业与员工的新型绿色关系模式,使企业在新世纪获取竞争优势.     

宗教和技术发凡

通过对中国的儒教、佛教、道教和西方的犹太-基督教等主要教派的技术观进行梳理,便可发现宗教和技术在长期的历史发展中形成了丰富多样的关系,既有血与火一般的对立和冲突,也有共生和共融,更有互不相干之时。技术和宗教各有其存在的空间,技术主要是同客观的物质世界打交道,宗教主要是同世界的价值观念打交道。技术虽能解决人类物质文明方面的问题,却不能完全解决人类精神文明和精神归宿问题,而且技术本身还有关乎造福人类抑或贻害人类的发展方向问题。为确保技术沿着造福人类的方向健康发展,需要诸多社会力量和文化因素的协同作用,而宗教无疑是其中一种重要的力量和因素。     

Distribution of sand dunes and sand shifts along the southern fringe of the Mu Us Desert since the Ming Dynasty

This article takes the two segments of the Ming Great Walls, Dabian and Erbian, and their associated barracks and forts as geographical references. Based on a detailed scrutiny of historical records of the Ming and Qing dynasties, and on field surveys, the southern boundaries of the sand dunes and sand shifts of the Mu Us Desert in the Ming and Qing dynasties are carefully reconstructed. A comparison of the southern boundaries of the sand dunes and sand shifts of the Mu Us Desert in Ming and Qing with the modern boundary revealed in remote sensing imagery clearly shows that the southern boundary of dunes and shifts in the Mu us Desert has expanded only in a few areas and on a small scale. In the area to the south of Changle Fort, along the direction of annually prevailing winds, sand drifts have penetrated through the Jialu River valley into the loess region and have formed a sand strip of 32 km long and 3 km wide. To the east of Qingping Fort, sand drifts penetrated toward the eastern loess region through the Luhe River valley and have formed another sand strip of 8 km long and 2 km wide. Generally speaking, though the intensity of human activity has been increasing in this area since the Ming Dynasty, the Mu Us Desert has not significantly expanded toward the southeast or southwest. The sand-loess boundary in the southern fringe of the Mu Us Desert has been almost unchanged since the Ming Dynasty.     

A novel method to improve the performance of heatexchanger——Temperaturefields coordination of fluids

The methods to enhance the heat transfer in heat exchanger may be classified into two levels: one is to improve the heat transfer coefficient; the other is to upgrade the whole arrangement of the heat exchangers. For the second level, the performance of heat exchanger can be upgraded by increasing the coordination degree between the temperature fields of cold and hot fluids. When the temperature distributions are similar to each other, the temperature difference field (TDF) is more uniform, which means that the temperature fields are more coordinated with each other. For the cross-flow heat exchanger, rearrangement of the heat exchange surface area should improve the heat transfer effectiveness, which is even equal to that of the counter-flow heat exchanger when the surface area is reassigned optimally. For the multi-stream heat exchanger, the thermal performance is also dependent on the uniformity of the TDF, and the parallel-flow arrangement may achieve higher heat exchange effectiveness than the counter-flow arrangement, which indicates that the performance of heat exchanger depends on the coordination degree of temperature fields instead of the flow arrangement.     

高校图书馆数据库建设浅议

文章阐述了高校图书馆建立数据库的意义及优势,数据库建设中的标准化问题以及在建库中 需解决的问题和应采取的措施。     

试论声乐教学中的情感问题

声乐教育中的情感问题始终是歌唱艺术中的最重要问题。要真正达到声情并茂,只有用心去体会,用多层次的“情”与一定的审美技能相互结合,才能达到完美境界。     

关于强纯整半群

本文在研究匀称带及其对应半格的匀称性中，提出了强纯整半群的概念，证明了强纯整半群不必是逆半群，因此这是比逆半群宽的一类纯整半群。文中又定义了基本强纯整半群，得到了基本强纯整半群同构于Hall半群WB的满幂纯整半群，最后证明了若带B匀称，则B所对应的半格也是匀称的。     

微波辐射条件下4-烷氧基苯乙酸的合成

作者采用常压微波辐射的方法，以4－烷氧基苯乙酮为原料，合成了一系列4－烷氧基苯乙酸。该法反应速度快，收率高，设备简单，对于徽皮在有机合成中的应用以及苯乙酮类化合物的Willgerodt反应的研究均具有一定价值。