Simulation of temperature distribution in hot filament chemical vapor deposition diamond films growth on SiC seals

In this study, the temperature and gas velocity distributions in hot filament chemical vapor deposition(HFCVD) diamond film growth on the end surfaces of seals are simulated by the finite volume method. The influence of filament diameter, filament separation and rotational speed of the substrates is considered. Firstly,the simulation model is established by simplifying operating conditions to simulate the temperature and gas velocity distributions. Thereafter, the deposition parameters are optimized as 0.6 mm filament diameter, 18 mm filament separation and 5 r/min rotational speed to get the uniform temperature distribution. Under the influence of the rotational speed, the difference between temperature gradients along the directions perpendicular to the filament and parallel to the filament becomes narrow, it is consistent with the actual condition, and the maximum temperature difference on the substrates decreases to 7.4?C. Furthermore, the effect of the rotational speed on the gas velocity distribution is studied. Finally, diamond films are deposited on the end surfaces of Si C seals with the optimized deposition parameters. The characterizations by scanning electron microscopy(SEM) and Raman spectroscopy exhibit a layer of homogeneous diamond films with fine-faceted crystals and uniform thickness. The results validate the simulation model.     

公共交通调度运营管理系统应实现的功能探讨

本文分社会协调层和企业运营管理层两个层面分析研究了公共交通调度运营管理系统应实现的功能,结合国外不同城市在公交线网规划、调度运营组织、公交服务与管理、政府的市场监管、公交运营模式和体制等方面的发展比较,对我国公共交通调度运营管理系统的建设功能进行了论述.     

用Arena进行供应链建模和仿真

提出了在用Arena软件对供应链进行仿真建模研究中的一些思路，通过计算机对供应链系统的仿真分析，不仅可以使得管理人员对由于从销售端到供应端的需求变化引起的“牛鞭效应”进行较为深入和直观的分析，同时也可以在模型中快速对不同物流管理策略和方案进行测评．整个供应链和供应链中各环节的平均库存水平和服务水平是所介绍的模型中的主要供应链绩效指标．文中采用了由供应商、制造商、分销商、零售商和客户所组成的传统供应链结构进行仿真建模，同时介绍了完成的第一个Arena仿真模型．     

习惯性流产患者精神状况探讨

采用习惯性流产妇女问卷，抑郁自评量表、焦虑自评量表、症状自评量表，对42例习惯性流产妇女和42例正常生育妇女（对照组）的精神状况进行了测评。结果：习惯性流产妇女90．5％感到精神压力，害怕再次妊娠流产，比对照组精神症状多，抑郁程度重，焦虑频度高。提示习惯性流产可能与精神心理因素有关；在对习惯性流产患者进行躯体治疗的同时，应提供心理疏导。     

光网络业务恢复算法研究

光网络拓扑结构的变化破坏网络中端到端的连接业务和业务环．根据原有业务路由和结构改变后的网络结构，从原有业务的正向和反向搜索，找出原有业务路由的正向和反向断点；通过回溯法和路由算法搜索出断点之间的路由，连接正向断点之前的路由、断点之间的路由和反向断点之后的路由实现业务恢复。     

舰艇动力系统监控设备维修训练平台的研制

为了解决舰艇动力系统监控设备维修技术要求高,训练难度大的问题,研制了基于模拟工作载体的舰艇动力系统监控设备维修训练平台。通过搭建油水管路和压缩空气管路模拟工作环境,安装舰用监控设备和仪器,实现了舰艇动力系统监控设备的功能模拟和操作使用,能够完成监控设备的操作使用、维护维修的教学和训练。实践证明,该平台适用于部队和院校,不仅能够保证多组人员同时开展监控设备技能训练,同时避免了动力系统实装的缺乏造成的影响和技能训练对实装造成的损坏。     

自主水下机器人下潜困难问题的数值仿真与试验研究

自主水下机器人在近水面运动时,受到文丘里效应产生向上吸力的影响,使得潜器初始下潜困难,近水面的深度保持能力也受到影响。为了研究水下潜器近水面下潜困难问题,文章运用计算流体力学（CFD）软件对某AUV主体周围流场进行近水面数值模拟。模拟结果表明,影响升力和抬头力矩的主要因素是初始的下潜深度和速度。水域试验表明随着初始下潜深度的增加,AUV 的下潜将变得越来越容易,这与模拟结果相一致。     

质子交换膜燃料电池接触电阻研究进展

质子交换膜燃料电池(PEMFC)接触电阻问题是制约其商业化发展的一个重要因素。影响接触电阻的因素可归纳为电池材料、组装参数、工作参数和其他因素。本文主要介绍了PEMFC的接触电阻及其影响因素,并综述了降低接触电阻的方法。     

船舶电力信息网络脆弱性分析

船舶电力信息网络的脆弱性分析对确保船舶电网安全、稳定、高效的运行有着重要意义。本文以复杂网络理论为基础,对船舶电力信息网络的脆弱性进行了研究。首先对某一具体的船舶电力信息网络拓扑结构进行抽象,然后在此基础上运用复杂网络理论计算船舶电力信息网络节点脆弱性和链路脆弱性,由此找出整个网络中最脆弱的部分。分析结果表明,该研究可为船舶电力信息网络的优化设计提供依据,并且在在拓扑结构方面着手对信息网络进行了优化提高。     

Comparing prediction methods for maritime accidents

ABSTRACT

The purpose of maritime accident prediction is to reasonably forecast an accident occurring in the future. In determining the level of maritime traffic management safety, it is important to analyze development trends of existing traffic conditions. Common prediction methods for maritime accidents include regression analysis, grey system models (GM) and exponential smoothing. In this study, a brief introduction is provided that discusses the aforementioned prediction models, including the associated methods and characteristics of each analysis, which form the basis for an attempt to apply a residual error correction model designed to optimize the grey system model. Based on the results, in which the model is verified using two different types of maritime accident data (linear smooth type and random-fluctuation type, respectively), the prediction accuracy and the applicability were validated. A discussion is then presented on how to apply the Markov model as a way to optimize the grey system model. This method, which proved to be correct in terms of prediction accuracy and applicability, is explored through empirical analysis. Although the accuracy of the residual error correction model is usually higher than the accuracy of the original GM (1,1), the effect of the Markov correction model is not always superior to the original GM (1,1). In addition, the accuracy of the former model depends on the characteristics of the original data, the status partition and the determination method for the status transition matrix.