切边V带切割方法的探讨

经对几种切边Ｖ带的成型和切割方法的分析比较，而总结出一种既能满足外观质量要求，保证使用性能，又能节省大量原材料的切边Ｖ带的切割方法。     

35t/h 循环流化床锅炉冷态试验和启动运行工况的分析

介绍了３５ｔ／ｈ循环流化床锅炉冷态试验和启动运行情况，总结了一些循环流化床运行的经验，并对调试中出现的问题进行了简要的分析     

逆境中求发展——略论房地产“冷”中的机遇

自国家紧缩银根以来,我国的房地产市场一直处于相对萧条的状态。房地产公司要从“冷”的一面看到房地产市场“热”的一面,分析其有利因素,抓住机遇,促进本公司健康顺利地发展。     

确定相似材料配方的正交试验法及其程序应用

本文讨论了正交设计法用于相似材料配方试验的合理性,提出解决有关分析问题的指标变换法,并在此基础上编制包括全部分析过程的L934—1微机程序.通过实际应用,证明该法正确可行,所编程序可以快速高效地分析试验成果.     

基于Excel的掷硬币实验

该文介绍运用Excel演示掷硬币实验的方法。     

基于Petri网的高校创收跟踪审计系统主控模块工作流建模

Petri网通过工作流系统来处理一些大型案例.每个案例有一个唯一的标识,案例在出现和消失之间总是处于某个特定状态,可以充分运用案例的相关属性使用Petri网建立工作流.高校创收项目全程跟踪审计系统就是一个典型的工作流案例,主控模块项目立项、项目实施和项目结算,每个模块内部和模块与模块之间涉及到流程,都需要审批,是工作流的过程.     

Characterization of two phase flows in chemical engineering reactors

Most industrial processes like fermentation, hydrogenation, oxidation, water treatment, petrochemical, nuclear and aerospace involve intimate contact between continuous phase and dispersed phase. Bubble columns and external loop airlifts are commonly used in these operations. Although these reactors are widely used, and extensive research has been carried out there exists no perfect model to characterize the local hydrodynamics and mass transfer. Computational fluid dynamics has also evolved recently trying to model the flow and transfer within these reactors but a lot of results are conflicting. Besides, there is a need to validate these results with experimental work. This work is dedicated to the experimental methods of measuring the local parameters such as the gas hold-up, the bubble velocities, the liquid velocity, bubble sizes. Two intrusive methods are used in this study, hot film anemometry for measurements of liquid phase and bi-optic probe for the gas phase.Although intrusive methods may interfere with fluid flow, presently they are the most adapted for real industrial processes with opaque equipment walls and high gas hold-ups compared to non-intrusive methods such as imagery. In this study, an external loop airlift of 16.5 l capacity is used. Local variables are measured in the riser of an external loop airlift reactor in air/water medium. The results are presented in the form of the radial profiles of void fraction, bubble diameter, liquid velocities at superficial gas velocities ranging from 0.03 to 0.11 m/s. The axial variations of the same parameters are also investigated. The results suggest that the bi-optical probe and hot film anemometer can reliably predict flow characteristics in high gas hold up contactors.     

The influence of material build up around artificial defects on rolling contact fatigue life and failure mechanism

This paper reports the results obtained in tests conducted to evaluate the evolution of wear tracks and artificial defects under rolling contact fatigue (RCF) loading and its effect on RCF life. The experiments were conducted on specimens of different materials commonly used in rolling bearings and gears. The artificial defects were introduced with the rounded tip of a Rockwell-C type indenter, with a diameter of 120 μm. The evolution of the micro-roughness profiles was followed, in the rolling and transversal directions, for both, artificial defect and wear track. The RCF lives of the samples were correlated with the build up height. Furthermore, the RCF lives of three variants of the SAE 52100 steel with artificial defects were compared to those obtained for the same variants where the build ups had been machined off. In the later case, the lives were observed to increased by a factor close to two; while the spall appearance remained unchanged indicating a similar failure mechanism. These results give room to question the precision and validity of finite element models, when analyzing artificial defects without proper accounting for the build up, i.e. surface roughness, and subsequent life theories formulated to match the numerical results. This paper also deals with the influence of artificial defects (when used to accelerate tests) on the life reduction factor for different materials, which was observed to be dependent on the material hardness.     

基于SSL技术的自学考试网上报名系统的设计与实现

随着Internet的普及,为了解决自学考试长期以来都是手工报名的弊端,提高自学考试考务工作者的工作效率,设计并实现了采用JSP、SSL安全协议、Oracle10g等技术的自学考试网上报名系统。该系统主要实现了考生网上报名和在线支付系统,并提供了一些辅助功能。该文对网上报名系统的设计思路进行了说明,重点介绍了基于SSL安全交易协议的在线支付系统的设计与实现。