输入设备在Vega应用中的接入方法研究

Vega软件环境默认的输人设备为鼠标，以其控制实体或视点的运动不够形象直观，需要将特定的输人设备应用到视景仿真系统中。在分析了Vega结构和工作原理的基础上，通过设计自定义的运动模式以及创建管理输人设备的Vega类实例，将特定的输人设备接人到基于Vega的视景仿真应用中。结果表明，该方法操作简单灵活，感觉直观，有效地改善了仿真实验效果。     

关于船用齿轮机构输入功率的补偿

船舶航行时船体中拱及中垂弯曲变形使沿船体纵向布置的齿轮机构的轴承支座中心距产生缩减.这种中心距缩减会导致互相啮合的两齿轮间产生附加的径向压力,从而使齿轮机构处于双面啮合工作状态.本文分析及计算了齿轮机构在该双面啮合工作状态时齿间摩擦及轴承摩擦所消耗的功率,并提出能满足船用齿轮机构正常运行要求的输入功率补偿公式.     

信号电源输入指标的优化探讨

针对铁路信号电源屏行业标准中信号输入电源的相关指标进行分析,并提出优化方案,探讨信号电源设备为确保正常供电应采取的保护措施,提高信号电源设备的适用性.     

柴油机燃油电控喷射用快速电磁阀的动力学分析

本文分析了快速电磁阀的动力学特性及保证电磁阀快速动作的线圈外施电压波形:进而提出了在实际采用阶梯波外施电压条件下电磁阀动力学特性的计算机模拟计算方法。     

LY12铝合金搅拌摩擦焊工艺研究

对LY12铝合金进行了搅拌摩擦焊接工艺试验,并对焊接接头进行了金相观察和力学性能检测.试验结果表明,合理的焊接参数匹配是取得性能优良焊接接头的前提.当旋转速度为905 r/m in、焊接速度为33.6 mm/m in、肩部压力为48MPa时施焊,可获得成型良好无缺陷焊接接头,且焊缝区晶粒细小.搅拌摩擦焊焊接轧态LY12铝合金时,焊接时的热输入可部分消除接头处金属的冷作硬化.随着焊接速度的提高,焊接热输入量降低,消除冷作硬化的能力减弱,焊接接头抗拉强度提高.     

车桥回转件CAPP系统中零件信息的输入

零件信息输入是CAPP系统中的一个关X技术问题。本文介绍了一个基于AUt0CAD环境下开发的零件信息输入方法一特征形京法，对商品化CAD环境下实现CAPP信息输入作了一些探讨。     

New applications of EXIT chart for iterative decoding systems

Applications on iterative control and multiple input multiple output （MIMO） system were developed. Two new charts derived from extrinsic information transfer （EXIT） chart were employed as the designing tools, which are called as output mutual information chart with defined iterative degree （DID） chart and near optimum output mutual information （NOMI） chart respectively. Different from the EXIT chart, they can show the iterative performance on the whole signal-to-noise ratio range with one single curve, whereas computation complexity is greatly reduced compared with conventional bit error ratio （BER） performance curve. The iterative control was implemented according to a near-optimum iterative degree vector determined by NOMI chart, the reasonability of uncertain parameters was analyzed in one MIMO system. The concepts were illustrated based on bit-interleaved coded modulation with iterative decoding （BICM-ID）.     

EDITORIAL: FINANCIAL CREATIVITY

This paper sets out the developments in world shipbuilding policy that have occurred in the past decade. It reviews and outlines the situation that existed in the late 1990s, when an Organization for Economic Co-operation and Development (OECD) agreement on the elimination of shipyard operating subsidies was tantalisingly close. After the Introduction, the second section provides a brief review of the development of the industry over the past three decades, setting the context for developments since 1997. The third section discusses the complaint of the European Union (EU) to the World Trade Organization (WTO) concerning the Republic of Korea's support for its shipbuilding sector, and its counterclaim over the EU's temporary defence mechanism (TDM). It is argued that the core of the EU's case at the WTO was flawed, and that the reintroduction of an operating subsidy via the TDM was a mistake. The only prospect for regularizing competition in this area lies in the negotiation of the OECD agreement that was completed, but not ratified, in 1994. Given the souring of relations between two of the main players in this area, the prospects for such a settlement seem remote. The fourth section uses Olson's theory of groups to argue that the European Commission's actions were driven primarily by industry pressure groups, and failed to consider the potential views of other European stakeholders, in particular the taxpayers. Given the failure of the EU's action at the WTO, the future direction of European shipbuilding policy will have to focus on strategies for internal development and improved industrial competitiveness.     

无纵向风下环境压强对拱顶最高温度影响数值研究

为了给高海拔隧道火灾防灾救援设计提供参考依据，通过火灾动态模拟软件(FDS)建立全尺寸模型隧道，设置5种不同环境压强，研究环境压强对隧道火灾拱顶最高温度的影响。结果表明： 1)相同火源热释放速率(HRR)下，拱顶最高温度随着压强降低而增大； 2)环境压强降低引起的空气密度与卷吸强度变化是造成拱顶最高温度变化的主要原因。基于理论分析和数值计算结果，提出考虑环境压强的拱顶最高温度预测模型。预测模型拱顶最高温度与考虑环境压强的无量纲热释放速率的2/3次幂成正比，试验数据验证了预测模型的可靠性。