Beyond the financial crisis: a way forward with development paradigm

As the impact of the financial crisis spreads worldwide, it has become a top priority of various countries, international institutions, entrepreneurs and scholars to find innovative and creative ways to face this challenge. As Hazel Henderson (2002) has pointed out, “the world has not fallen into a financial crisis, but fundamentally fell into a crisis of development paradigm.” We need to reflect seriously on this paradigm and rethink of the social and economic models and cultural values for meeting the challenges of this crisis. The paper introduces key issues of development within a global context, and explores the shift of the value system from hard technology centered to soft technology-based future direction of human development.     

110kV电缆竣工试验引发事故的分析

通过对一起110kV XLPE电缆线路竣工试验所引发的事故进行分析,提出110kV电缆交流试验应该注意的一些问题,以期引起同行的借鉴和参考。     

在线CT导纳测试及其应用

讨论了常见电流互感器(CT)的故障及其特征,提出了一种实现在线电流互感器测试的新方法——导纳测试法;介绍了澳大利亚红相电力设备公司505型导纳测试仪的工作原理及实用性。     

煤层气抽采直流微网建模与稳定性分析

针对目前煤层气抽采现场用电不合理现状,构建一种新型煤层气抽采直流微网供电系统,并对该直流微网系统稳定性及控制策略进行研究。煤层气抽采直流微网供电系统分三层结构:第一层由光伏和蓄电池组成能量供给层;第二层由双向Buck/Boost变换器构成能量传输和分配层;第三层由煤层气抽采机构成负荷层。基于此架构推导了第一、二层输出阻抗Zo(s),并建立第三层煤层气抽采机电动机输入阻抗Zin(s)与受控源K??m串联的小信号模型,在此基础上得到系统全局小信号模型。考虑到呈现负阻抗特性的煤层气抽采机电动机周期性动态交变负荷引起的系统不稳定,在能量传输和分配层分析并讨论了一种基于虚拟阻抗的直流微网稳定性控制策略,以及利用下垂控制实现负荷功率动态平衡分配的方法。进一步利用阻抗匹配原则求解多项式1/(1+Zo(s)/Zin(s))主导极点,比较采取该稳定性控制策略前后的主导极点位置并分析直流微网系统稳定性。最后基于Matlab/Simulink搭建由光伏阵列、储能单元和煤层气抽采机组成的煤层气抽采直流微网系统模型,系统仿真证明了稳定性控制策略的有效性。     

Correction strategy of fuel injection quantity during pilot-main injection for common rail system

Journal of Mechanical Science and Technology - Common rail system is a key technology of energy saving and emission reduction for modern diesel engines. Multiple injection, as one of the most...     

实施汽轮机单阀改顺序阀运行效果分析

岱海发电厂Ⅰ期2台600MW汽轮机为上海汽轮机有限公司引进美国西屋技术生产的汽轮机,在单阀切顺序阀运行后存在瓦温高、轴振大、上下缸温差大等问题。针对这些问题,进行了单阀切换为顺序阀试验,对存在的问题采取了改进措施,有效地提高了机组效率。     

Effects of Tearing Conditions on the Crack Propagation in a Monolayer Graphene Sheet

The path of crack propagation in a graphene sheet is significant for graphene patterning via the tearing approach. In this study, we evaluate the fracture properties of pre-cracked graphene during the tearing process, with consideration of the effects of the aspect ratio, loading speed, loading direction, and ambient temperatures on the crack propagation in the monolayer sheet. Some remarkable conclusions are drawn based on the molecular dynamic simulation results, i.e., a higher loading speed may result in a complicated path of crack propagation, and the propagation of an armchair crack may be accompanied by sp carbon links at high temperatures. The reason for this is that the stronger thermal vibration reduces the load stress difference near the crack tip and, therefore, the crack tip can pass through the sp link. A crack propagates more easily along the zigzag direction than along the armchair direction. The out-of-plane tearing is more suitable than the in-plane tearing for graphene patterning. The path of crack propagation can be adjusted by changing the loading direction, e.g., a rectangular graphene ribbon can be produced by oblique tearing. This new understanding will benefit the application of graphene patterning via the tearing approach.     

基于PIC16F946的CO气体检测仪

介绍了一种便携式CO气体检测仪的开发,论述了仪器的硬件原理图、一氧化碳气体传感器的参数模型分析以及软件的程序流程图,该仪器可实现检测空气中CO的含量,并可自动进行声、光以及震动报警,可通过按键设定二级报警值,并且可以对仪器进行标定,仪器以美国microchip公司的微控制器PIC16F946作为核心控制单元,分辨率为lppm;误差为士3%,采用3V的锂电池可以连续工作9000h以上,可广泛用于工业生产、环保、汽车、家庭等一氧化碳泄漏和不完全燃烧的检测报警.     

国家投资体制改革形势下的工程项目管理模式探索

上海市高级人民法院工程项目管理工作是运用建设、经济、技术、法律方面知识和经验实施管理的一项成功的工程咨询业务实例,同时也对国家投资体制改革形势下的工程咨询和项目管理模式进行了有益的探索。