铸造合金凝固过程瞬时应力的测试

以计算机采集处理系统为手段,测试了应力框铸件凝固过程的瞬时应力.结果表明,该方法简便、速度快,精度高,可获得铸件凝固过程瞬时应力及温度的动态变化过程。     

Rapid synthesis of La0.7Sr0.3MnO3+λ catalysts by microwave irradiation process

Microwave irradiation processing (MIP) was considered as a potential method to synthesize perovskite-type oxides rapidly, cleanly and energy-efficiently. In this paper, La_0.7Sr_0.3MnO_3+λ, a kind of promising catalyst for automobile exhaust purification, was successfully prepared by MIP in not more than 5 min. The sol–gel method was also used for comparison. All the samples were evaluated by catalytic activity tests in the simulated exhaust and characterized by XRD, BET, TEM and XRF analyses. The results showed that the integrated perovskite-type phase and uniform particle size were obtained in the microwave-treated samples. And those ones exhibited a better oxidation activity under slightly oxygen-rich condition than that by sol–gel method, which may be related to more A-site cation vacancies and larger bulk oxygen content generated in MIP. Possible formation mechanism of perovskites in MIP was also discussed.     

Comparison of prototype and rote instruction of English names for Chinese visual characters

This study compared prototype and rote instruction of English names for Chinese visual characters. In the prototype condition, participants were taught the meaning of the prototype that served as the distinctive feature of multicomponent characters. In the rote condition, participants traced the character and wrote its translation. Participants learned more rapidly and maintained more words in the prototype condition.     

坐便器与水箱配件在标准中的配套性要求

详细介绍了坐便器与水箱配件在新标准中的配套性技术要求,分析了2种产品配套性指标和相关的检测方法。     

A minimum cost assessment method for composite generation andtransmission system expansion planning

Composite generation and transmission system expansion analysis should take into account both economic considerations and adequacy requirements. An optimum expansion plan should achieve the minimum total investment, operation and damage cost. A minimum cost assessment method for composite system expansion planning, which can be used to consider generation expansion and transmission expansion simultaneously, is presented. The minimization model proposed to incorporate both operating and outage costs can recognize different customer damage functions at different load buses and includes the duration of the simulated contingency system states . A computer program based on the presented method has been developed to provide a set of line, load bus, generator bus and system indices which can be used to select optimal expansion plans at different load growth levels. Case studies in which the method is applied to the IEEE Modified Reliability Test System indicate its effectiveness     

宽带钢冷轧机颤振控制的数值模拟

本文以较为准确的轧机振动状态下的轧制压力模型为基础，对宽带钢冷轧机干摩擦阻尼减振进行了数值模拟的研究。研究结果与实际观测值相等。     

特种钢用结晶器铜管破裂原因分析

通过对某特钢厂破裂的结晶器铜管进行金相实验、扫描电镜和能谱分析,并结合结晶器的生产、使用及失效过程情况,综合受力分析,认为铜管破裂原因主要是环境介质硫渗入形成硫化物,在拉应力作用下,裂纹沿脆性质点扩展导致的破坏。     

计算机网络安全问题及防范对策

文章简单阐述了当前计算机网络所面临的主要安全威胁,并在此基础上提出了分层控制的方案,建立了不同层次间网络安全的防范措施,希望以此来提高网络安全性。