激光辐照制备搪瓷涂层

激光辐照制备的搪瓷涂层表面粗糙,与金属基材结合牢固。一般由 Si,Al,Na,K,B,F,O等元素组成。在激光辐照过程中 K,Na 明显地挥发,从而在涂层中的含量明显减少;Co,Ni,主要分布在界面附近;Fe 元素也由基材进入涂层,呈梯度状分布,在界面过渡区含量很高,在涂层内含量很低。搪瓷涂层的形成与激光辐照参数,特别与激光功率间存在极为密切的关系;只有选用合理的参数,才能制得搪瓷涂层。     

Vibration Monitoring and Diagnosis of Pipe-line Pumps on Offshore Platforms

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China＇s Electric Power Reform：Different Economics and Challenges

China＇s electric power reform has followed the western reform format, however, it doest not seem to have endorsed the liberalization ideology underlying the reform model. This raises the concern of whether and how a competitive power market may be established and reform objectives reached. The new market competition model is easy to build in theory. The experience of many countries suggests that the market reform is extremely difficult because of the interruptions by different interest groups. To transform a centrally planned power sector into a competitive power market is a daunting task. Policy makers need to take into consideration the transitional nature of the economy and power industry as they implement the competitive power market model.     

燃煤电站锅炉排烟中潜热的回收

提高燃烧效率和(或者)从排烟中回收余热都能够改善锅炉效率。目前的研究是确定同时回收潜热和显热时热和烟的收益比率。通过在一个350MW热电站中的一台交叉流管状换热器传热和传质的数学模拟,获得了理论结果。这一结果表明,在烟气温度为150℃时,由于从排烟中回收潜热,锅炉效率可以提高5—6％。对换热器表面的最大腐蚀率做了予测。     

A BOUNDARY INTEGRAL EQUATION AND ITS NUMERICAL SOLUTION OF POTENTIAL FLOW AROUND SURFACE-IRREGULA-RITIES

In this paper,using complex functional theory,the authors turn the potentialflow around the surface irregularities in a pressure conduit and semi-infinite platforms intoDirichlet problem.Based on Schwarz formula and by the application of Plemelj's formula,theauthors change the problem into the integration of a Cauchy boundary integral equation in theflow plane through the substitution of variables.Using numerical integration,the authors obtainthe velocity distribution and pressure coefficient along surface irregularities and platforms.Thephysical concept of this method is clear,the convergent speed is rapid and the computative effi-ciency is high.The calculated values agree well with the measured results.It is an effective andsimple method in solving potential flow.     

电力电子系统应用的时间域网络解析器的精确度和速度

本文通过比较5个商业软件包的精确度和执行时间，研究了具有固定时间和变换时间的网络仿真方法的性能差异。包含了多个三相二极管整流器和一个PWM电压源逆变器的一系列基准实例显示：对于线性电路来说，固定时间步长法的仿真时间更短一些；然而，为了得到精确的结果，即使对于低开关频率的PWM应用都可能需要非常小的时间步长。否则，如果使用的时间步长过大，即使波形看起来是正确的，PWM逆变器控制信号也可能有严重的错误。     

熔融 NaCl-(Na,K)_2SO_4引起的 Fe-Cr 合金的热腐蚀

本文采用电化学方法研究了 Fe-Cr 合金在800℃、熔融 NaCl-(Na,K)_2SO_4中的腐蚀行为,并对腐蚀产物进行了观察和分析。结果表明,提高合金 Cr 含量可以改善合金耐蚀性能。氧化-硫化是Fe5Cr、Fe10Cr 合金腐蚀破坏的主要方式;氧化膜的熔融反应是 Fe20Cr、Fe25Cr 合金加速腐蚀的主要原因。同时,氧化膜的机械破裂也加速了合金的腐蚀。     

A3钢的工业大气腐蚀

在辽宁省工业城市进行 A3钢大气暴露试验。两年后测出不同地点腐蚀率。依据所记录的各试验点的气象数据和污染数据,讨论了 A3钢的大气腐蚀规律。     

AQSIQ Sends Working Groups to Implement the Spirit of National Quality Working Conference

On August 1st, the General Administration of Quality Supervision, Inspection and Quarantine (AQSIQ) convened a conference to transmit the spirit of national quality work and study an important speech regarding standards from Wen Jiabao,Premier of the State Council.     

Ti_3Al金属间化合物的熔盐热腐蚀

采用电化学方法并结合扫描电镜、X 射线衍射、电子探针和能谱等物相分析技术研究了 Ti_3Al 金属间化合物在800℃熔融 NaCl-(Na,K)_2SO_4体系中的腐蚀行为。结果表明,Ti_3Al 合金耐熔盐腐蚀性能远低于 Ni 基 IN738合金。腐蚀时在合金表面形成外层为 TiO_2;内层为富 Nb 的Nb_2O_5,Al_2O_3,TiO_2的混合层和中间层为富 Al 的 TiO_2,Al_2O_3混合层的多层腐蚀层结构。Ti 快速向外扩散和氧向内扩散使合金表面腐蚀产物层迅速增厚。腐蚀产物内层的富 Nb 氧化物破坏了膜层与合金基体的粘附性。