数字式三相智能电能表的研制

介绍了一款基于单片机Atmega128的三相数字式智能电能表的研制,从电路硬件选型、电路设计及制作进行论述。所设计的智能电能表与同类产品相比具有集成度高、功能强、成本更低廉、抗干扰能力强、功耗低等优点。随着未来电能智能化管理及电能表集抄需求,该款表具有很大的应用前景。     

电能质量智能在线监测系统设计

论述了电能质量问题的内容及其对电力系统的影响,设计了一种基于嵌入式技术的电能质量在线监控系统,给出了系统的硬件结构图和软件结构图及流程图,进行了样机的功能性验证试验,证明该系统对于构成具有智能化的监控及通信系统具有一定的应用价值。     

Residual strength prediction of multiple cracked stiffened panels

Prediction of the coalescence of adjacent cracks is critical for residual strength estimation of structures under multiple site damage conditions. A methodology successfully developed for the case of crack link‐up prediction of un‐stiffened plates, is extended for the case of typical cracked stiffened aircraft panels. The proposed link‐up criterion is based on the change in the magnitudes of elastic and plastic strain energies of the stiffened panel, before and after the cracks coalesce. The strain energy magnitudes of interest are calculated using non‐linear elastic–plastic finite‐element analysis. For the application and verification of the method, experimental results from the open literature are used. Residual strength values calculated by the proposed methodology are in good agreement with the experimental results. The present criterion provides superior results when compared to the existing and commonly applied link‐up criteria.     

Energy transfer mechanism of GdPO4: RE3+ (RE = Tb, Tm) under VUV-UV excitation

Polycrystal of GdPO₄:RE³⁺ (RE=Tb, Tm) phosphors were prepared by solid-state method. Vacuum ultraviolet excitation and emission spectrum and the energy transfer mechanism between the host and dopants of Tb³⁺ and Tm³⁺ were investigated respectively. The emission of Gd³⁺ at 313 nm was enhanced by the strong absorption of CTS of Tm³⁺ at 180 nm in GdPO₄: Tm. It has also been concluded that the excitation of Gd³⁺ is transferred to Tb³⁺ and then emission peaks of ⁵D_J→⁷F_J of Tb³⁺ were observed.     

户用PV系统设计

由于能源短缺和环境污染的问题日益严重,改善能源结构,保护环境,已成为我国在新世纪经济发展高速期所面临的重要课题。尤其是在居住建筑中,采用清洁、储量巨大、无地域限制和能源质量高等诸多优点的太阳能,成为近些年国内研究的热点,引起了各界的关注和重视,科研院所、相关企业等部门都在积极的探索和实践。本文介绍一种户用太阳能光伏发电系统(又称PV系统)的计算流程,仅供参考。     

铝电解槽热平衡测试计算中的几点问题

由于缺乏正规的标准，铝电解槽能量平衡测试中存在着一些概念混淆、计算方法和公式错误的情况，应引起测试工作者的注意，在测试计算前应认真制订方案，多查一些参考资料，核实所用公式、数据，避免发生失误。同时对于类似计算，由于计算机的应用，应尽可能采取精确算法。没必要采取一些非常粗糙的近似算法和经验值。     

新风动态负荷与空调节能

介绍利用空调软件对整栋大楼进行动态负荷计算分析,并以此选择空调设备,不但节省投资,而且达到节能效果.     

A bending specimen for constant energy release rate under controlled displacement conditions

A bending specimen that gives a constant energy release rate (independent on the crack length) under controlled displacement conditions is developed. It is assumed that engineering beam theory is applicable, i.e. that among other things, small deformations and linear elastic isotropic material can be assumed.A specific geometry is analyzed numerically by use of the finite element method and experimentally by manufacturing a specimen with the actual geometry in PMMA (polymethylmetacrylate) and then determining the specimen stiffness for different crack lengths.It is found that the geometry considered gives a constant energy release rate under controlled displacement conditions.     

基于van der Waals状态方程的剩余自由能模型

结合 Wong- Sandler的混合规则 ,即在无穷大压力下剩余 Helmholtz自由能与无穷小剩余 Gibbs自由能近似相等的关系 ,给出了一个基于 van der Waals状态方程的剩余自由能模型 ,由此得到可以描述汽液相平衡的活度系数模型。通过对 35个体系的考核表明 ,该模型可以较好的关联实验数据 ,包括极性与极性物系 ,其结果好于 Wilson、Mar-gules、NRTL与 Uniquac等模型的计算结果。同时 ,因为该模型基于 Wong- Sandler的混合规则 ,因此可以实现在理想溶液中 ,由 Wong- Sandler混合规则到 van der Waals混合规则平滑过渡。     

Fusion Innovative Confinement Concepts: 2004

This paper summarizes recent progress in fusion Innovative Confinement Concepts (ICC) as reported at the 2004 ICC Workshop held May 25–28, 2004 in Madison, Wisconsin. This was the third in an annual series of workshops on this topic. The purpose of these workshops is to provide a forum for those who are thinking and working beyond what is considered to be the current state of understanding of fusion concepts.