泊车咪表现场检定方法的选择

本文结合实际检定工作，对几种咪表现场检定方法进行分析，从而根据具体情况选择其中最有效最合理的一种方法。     

基于有功功率和无功功率控制的并联UPS系统

本文研究了一种并联UPS系统的均流控制方法,在有功功率和无功功率控制的基础上加入了输出滤波电感电流的直流分量控制。电感电流控制的加入可以有效的提高并联UPS系统的均流特性以及稳定性。两台30KVA三相四线UPS并联系统验证了该方法的可行性,实验证明该控制方法可以取得良好的并联均流效果。     

建筑工程多媒体仿真环境设计技术研究

结合作者运用多媒体仿真技术，研制建筑工程领域计算机仿真系统的实践，论述为实现工程力学场和建筑形态变化的动力学仿真，建造适用于系统环境和工具的理论和方法。     

电子数据处理在膜式煤气表检定管理中的应用

本文结合检定工作实际设计开发了利用计算机开展膜式煤气表检定数据处理及管理系统,为充分提高检定工作效率提供科学可靠的保障.     

300～400mm口径水表校验台不确定度分析

本文对校验台的不确定度进行了分析。此校验台可以检测DN300~400水表。     

A comparative study of tungsten-modified PtRu electrocatalysts for methanol oxidation

The carbon supported PtRu nanocatalyst is modified by two kinds of tungsten compounds, i.e., tungsten oxide (WO_x) and phosphotungstic acid (H₃PW₁₂O₄₀, PW₁₂), respectively, and the catalytic performances of the modified catalysts for methanol oxidation are evaluated. The results show that tungsten oxide and phosphotungstic acid exhibit different promoting effects on the catalytic performance of the PtRu nanocatalyst for methanol oxidation. The WO_x-modified PtRu nanocatalyst has a considerably high catalytic activity, which is attributed to the uniform distribution of PtRu nanoparticles on the carbon support and the strong metal-support interaction (SMSI) between the hypo-d-tungsten and the hyper-d-platinum. The PW₁₂-modified PtRu nanocatalyst has a good poison resistance, which is ascribed to the protective effect of the self-assembled PW₁₂ layer on the catalyst surface.     

水平螺翼式水表的"望、闻、问、切"

本文介绍了“望、闻、问、切”四种测量手段。通过这四种方法,可以对在用的水平螺翼式水表的运行状况进行分析。     

Elucidating the operating behavior of PEM fuel cell with nickel foam as cathode flow field

Metal foam material, which serves as an alternative replacement of the conventional flow distributor of proton exchange membrane(PEM) fuel cell, has been attracting much attention over last few decades. In this work, three-dimensional modeling work for PEM fuel cell containing metal foam as cathode flow distributor has been carried out. The fuel cell performance and operating characteristics of metal foam flow field and conventional parallel flow channel have been compared and discussed.The cell performance has been reasonably validated based on the corresponding experimental tests conducted in this study. The superior performance of PEM fuel cell with metal foam as cathode flow field benefits a lot from the uniform gas flow. The porous metal foam material provides more pathways for the water delivery at the interface of metal foam flow field and gas diffusion layer(GDL), accelerating water removal capability of cathode. Because of the significant oxygen transfer loss in diffusion limited parallel channel, the operation of PEM fuel cell with parallel channel is found to be more sensitive to cathode humidification and oxygen supply at inlet. Due to the more uniform and effective electron transport though the porous electrode, it is possible to use thinner GDL in metal foam PEM fuel cell. It is expected that this study could give a good baseline of operating behavior of PEM fuel cell with metal foam flow distributor.