土木结构试验网络化方法的研究和实现

文章介绍了土木结构试验液压伺服系统，并且实现一种基于SOCKET的客户端、服务端和控制器端的网络化改造方法，通过该方法改造后的系统不但可以实现土木结构抗震性能伪静力、拟动力试验，还可以进行NetSlab平台下的大型网络协同远程拟动力试验，实现了土木结构大型试验设备共享和远程教学的目的。     

Priority optimization and make‐to‐stock/make‐to‐order decision in multiproduct manufacturing systems

We consider a single‐stage multiproduct manufacturing facility producing a large number of end products. In order to reduce overall inventory costs, an efficient approach is to produce some items according to a make‐to‐stock (MTS) policy and others according to a make‐to‐order (MTO) policy. Items priority levels play a key role in the optimal MTO/MTS decisions for such typical large‐scale systems. To tackle this issue, the manufacturing facility is modeled as a multiproduct multipriority classes queuing system. We propose a general optimization procedure that selects near‐optimal priority classes, gives the associated flow control mode (MTO or MTS) for each product, and provides a lower bound and an upper bound with respect to the optimal cost. First, we illustrate efficiency of our optimization procedure for this class of nonlinear integer programs via several examples and by a numerical analysis, including a comparison with two alternative heuristics given in the literature. In addition, we provide managerial insights by exhibiting, under various parameter settings, the significant impact of an efficient priority level allocation among items on the inventory costs and on optimal splitting between MTO and MTS products.     

Computational thermodynamic study of SiC chemical vapor deposition from MTS-H2*

This study focuses on the computational thermodynamic analysis of the chemical vapor deposition (CVD) of SiC from the methyltrichlorosilane-hydrogen (MTS-H₂) using up-to-date thermodynamic databases. High-resolution computation has been performed with the fine intervals of temperature and pressure at the various H₂/MTS ratios of interest to systematically investigate the deposition condition range (800 to 1600°C, 0 to 26 664 Pa, and H₂/MTS ratios of 0.1 to 100) to guide experimental exploration. The influence of deposition parameters on the compositions and phase stabilities of the deposit and gas phase pertinent to vapor processing is elucidated. Low pressure and medium temperatures (1000 to 1400°C) are beneficial to reaching a higher SiC deposition efficiency and provide an optimal window for preparing a high-purity (>99 wt.% SiC) deposit. This optimal processing window expands significantly with an increasing H₂/MTS ratio (<20). These results are supported by a number of previous theoretical and experimental observations. The mass fraction of SiC in deposit is proposed as an additional perspective to understand the discrepancy between thermodynamic calculation and experimental observation of pure CVD SiC at low H₂/MTS ratios.     

主副本法多副本分布式并发控制的实现

讨论分布式数据库中的并发控制问题，结合相关的理论，设计了一个多副本的并发控制模型。运用分布式并发控制的主副本算法，使用MTS／COM＋技术，对并发控制机制进行了研究和基本实现。最终在客户端实现了针对分布式数据库多副本的读取和更新操作，达到更新一致性，具有较高的执行效率。     

基于Windows DNA体系结构的COM+应用编程

组件对象模型COM，DCOM，COM 是实现软件组件、面向对象编程的一项重要技术，是支持Windows DNA多层系统编程的核心。本文介绍应用COM 技术，实现基于Windows DNA体系结构的网络数据库编程。     

基于Windows DNA结构的发电机变压器组远程监录系统

为满足监录系统网络化的要求，构建了一个基于Windows DNA结构的发电机一变压器组远程监录系统。利用COM／COM 及其它软件技术，该系统还具有易维护、易扩展等优点。     

基于MTS/COM+和Windows DNA的三层企业级应用研究

阐述MTS/COM+技术以及WindowsDNA结构的概念和特点,并通过开发实例,对基于Client/Server两层和三层结构模式进行分析。最后,以Delphi6.0作为开发平台,成功实现了基于MTS/COM+中间件的目标系统。     

Evaluating MTS criterion in predicting mixed-mode crack extension under different loading conditions

The maximum tangential stress (MTS) criterion is one of the most widely used criteria for predicting the direction of crack extension. The suitability of this criterion is examined under different loading conditions using the extended finite element method (XFEM). Experimental and numerical results reported in the literature are considered to evaluate the validity and accuracy of the criterion. The results demonstrate that the MTS criterion evaluated by stress intensity factors (SIFs) can accurately predict the direction of crack propagation in specimens under direct tensile loading. This criterion overestimates the angle of crack initiation in the specimen under indirect tensile loading but underestimates the angle in the specimen subjected to 3-point bending. It is concluded that the MTS criterion based on SIFs could not accurately predict the direction of the crack initiation, which could, however, be determined properly based on the stress distribution around the crack tip obtained by the XFEM numerical models.     

基于多特征提取和改进马田系统的滚动轴承故障分类方法研究

为提高旋转机械的使用效率,及时识别滚动轴承的潜在故障,提出一种基于多特征提取和改进马田系统(MTS)的故障分类方法。通过时域、频域和自适应白噪声的完备经验模态分解(CEEMDAN)提取多维特征,构建初始特征集。结合马田系统和有向非循环图(DAG)的特点,构建DAG-MTS多分类模型,并将其运用到轴承故障诊断中。利用滚动轴承故障数据测试该模型的有效性和实用性,结果表明,该模型能够准确识别出滚动轴承的故障。     

无线IP通信技术分析与研究

第三代移动通信系统（如UMTS）和互联网相结合（如支持无线IP网络传输多媒体／话音的IP技术）将推动无线通信领域的巨大变革。主要分析了新一代基于IP的无线网络结构和它能提供的服务,以及对应的新一代终端设备。