格状编码和RS码级连技术在HDTV中应用的性能模拟

设计一种用于ＨＤＴＶ地面数字传输系统的级连格状编码和ＲＳ码方案，并对其在ＨＤＴＶ中应用进行计算机模拟。模拟结果表明：该级连格状编码方案在低信噪比具有较好的误码性能。     

铜蒸汽激光器双闸流管触发系统的研究

研制成用于钢蒸汽激光器的双间流管触发系统。用两个闸流管并联进行交替触发，总输入电功率达7．8kW。低功率运行时，激光器的效率为0．6％与单间流管激光器的效率一致。     

轴端沟槽底部激光强化工艺参数优化研究

分析了选用不同激光能量密度对HT300进行表面强化处理时，材料表面呈现的四种状况；未相变硬化、相变硬化、表面微熔与表面熔凝的金相组织。根据工艺要求，选取相变硬化方法对轴端沟槽底表面进行处理。分析了工件激光处理方法并通过试验研究，寻找轴端沟槽底部激光强化工艺参数；激光功率（P）、光斑直径（D）及扫描速度（V）的优化组合。硬度测试及耐磨性能试验表明：激光相变处理和激光熔凝处理后轴端沟槽底部表面较表面感应淬火硬度分别提高7%和34%，绝对磨损体积分别下降了13%和25%。实践证实，对轴端沟槽底部激光相变硬化处理方法较其他表面处理方法工艺简单，加工工件符合技术要求，试验结果对零件表面处理提供了可靠依据。     

A storage heat pump using an ‘ozone-friendly’ refrigerant

The paper describes the integration of a chemical and a vapour-compression heat pump for energy storage applications. The vapour-compression system is designed to operate using the UK cheap rate ‘Economy 7’ electricity tariff. The system is characterized thermodynamically using various refrigerant/absorbent pairs in the chemical storage circuit and an ozone-friendly refrigerant, R134a, in the vapour-compression circuit. Results indicate that the H₂O/Na₂S pair provides a high energy storage density and is the most suitable for use in this system. The paper also describes the design features of a domestic-sized version of this heat pump system. Air in the sunspace (conservatory) of a house was used as a heat source for the heat pump.     

Degradation of polyethylene terephthalate films in the presence of lubricants for HFC 134a: a critical issue for hermetic motor insulation systems

Earlier studies conducted in the use of sealed tubes with polyalkylene glycol lubricants and polyethylene terephthalete (PET) films revealed that the PET films exhibited embrittlement and (visual) degradation. This led to an investigation of PET embrittlement mechanisms with the new lubricants used with HFC 134a. The lubricants studied were three polypropylene glycols (the monol, the diol and the completely end-capped glycols), pentaerythritol ester and a blend of monol and ester. The effects of moisture content, temperature and lubricant structure were studied. All lubricants in this study were of viscosity grade ISO-32 (150 SUS). The results were compared to PET film embrittlement in the presence of CFC 12 and mineral oil. This study reconfirmed the earlier findings that the PET films must be dried to lower than 0.1 wt.% moisture content for use in hermetic systems. This paper discusses the effect of the moisture content of the lubricant and the effect of the lubricant structure on PET films. The dependence of the various mechanisms on temperature is shown. Esters and end-capped polyalkylene glycols are recommended for use with HFC 134a.     

小型办公网络组网

通过实例,对小型办公网络组网中涉及到的需求设计、网络连接、网络设备、设备连接等进行了论述。     

无篦条可逆锤式破碎机

首先介绍了锤式破碎机的现状及发展前景，主要阐述了无篦条可逆锤式破碎机的工作原理，较详细地介绍了本机的结构特点和性能优点。     

体积-表面淬火中加热温度的自动控制

根据表面-体积淬火奥氏体规范的要求，分析了感应加热过程中温度控制的特点和方式，并介绍了采用红外线光导纤维测温和微机控温技术成功用于体积-表面淬火中透热温度的自动控制。     

TRT入口方管道爆裂原因剖析

介绍了鞍钢7#高炉TRT装置入口方管道爆裂事故经过,进行了原因分析,并提出了解决措施。     

交流变频调速技术在二辊轧机压下系统中的应用

介绍一种采用变频调速技术控制的二辊轧机压下系统。该系统可控制轧机压下系统的速度在工艺要求的范围内无级可调，压下量以数字动态显示，控制准确、操作方便。文中对系统的组成及工作原理作了较详细的介绍。