强度调制／直接检测（IM／DD）光纤通信系统色散限制的研究

通过引入归一化脉宽Ｐ和相对脉冲展宽因子ｑ，提出了一个适用于ＩＭ／ＤＤ系统中各种眼图恶化量ｘ和归一化脉宽Ｐ的色散限制改进公式。通过与其它理论的比较、计算机仿真和对实验数据的分析，验证了该公式的正确性，并给出了其它结果的限制条件。研究表明：当眼图恶化量ｘ为１ｄＢ左右时，对２．５Ｇｂ／；外调制信号（α＝０）而言，非色散位移光纤ＩＭ／ＤＤ系统的色散因子γ约等于０．７９，所对应的系统再生中继距离约为９００余公里。     

Recent developments in the extrusion of helical gears

With an improved die, a method for manufacturing gears by means of tube extrusion has been developed to a stage where, without noticeable wear of the die, 40,000 workpieces can be manufactured. The paper presents a numerical analysis of the stresses and deflection of the die, offering also a comparison between the modified and the conventional symmetric orifice. Based on the results obtained and using recent work on crack prediction for extrusion dies, the area most prone to rupture is determined. Moreover, a concept for the precorrection of the die is offered to improve the tooth quality of the gears.     

矩形件排样的一种优化算法

排样问题是一种总体资源分配问题，这里根据矩形件排样的工艺要求，提出了矩形件排样的一种近似算法，将一块板材分成三部分，每部分排一种零件，使得减料方便，提高了劳动生产率。     

Improving communication energy efficiency in wireless networks powered by Renewable energy sources

Energy efficiency is an important issue in wireless networks where the nodes are powered by batteries. In this work, we analyze the energy consumption in one-transmitter-multiple-receiver communication and develop scheduling schemes to improve energy efficiency at the transmitter. Our focus is on systems powered by a renewable energy source such as solar power. We consider an environment where both energy and time to access the wireless channel and transmit data are limited, and data destined for different receivers have different values and incur different energy costs. We present optimal scheduling algorithms that selectively transmit data at calculated rates so that the throughput or the total transmission value is maximized under given time limits and energy constraints.     

Effects of various post-treatments on carbon nanotube films for reliable field emission

In this report, the FE characteristics of carbon nanotubes (CNTs) treated using both thermal annealing and mechanical coatings on the as-grown CNTs systematically studied. It was found that in the high temperature annealed samples, CNTs were attacked at its root during annealing due to a small amount of oxygen, and were pulled out of the substrate in places after FE measurements because of the contact resistance. However, for the mechanically coated samples both with spin on glass (SOG) and polymethyl methacrylate (PMMA), CNTs were found to be nearly intact after FE measurements and showed reliable FE characteristics over repeatable voltage scan. The reliability of CNTs during FE could be owing to the strong adhesion of CNTs to the substrate both by SOG and PMMA coatings.     

Application of Direct Ignition Technology with Minimum Gasified Oil in Lignite-Fired Boiler

The firing is in the stable condition and the rate of oil saving comes up to 64%, after Fularji Power Plant adopted the technology of minimum gasified oil igniting pulverized lignite directly and the technology of multistage coal combustion with energy amplified stage by stage.     

论新经济中企业人力资源的开发管理与创新

在新经济时代和经济全球化及知识经济时代的背景下,创新成为未来管理的主旋律,而企业人力资源管理的创新成为管理创新的主题,企业要主动适应环境的变化,加强人力资源的开发与管理.分析了新经济的内涵和特征,新经济时代企业所需人才的类型和素质,提高如何开发管理人力资源,以使企业保持恒久的竞争力.     

柴油机轴承盖螺栓断裂分析

柴油机发生多起轴承盖螺栓六角头与杆部过渡处断裂的故障,行驶里程为30000～70000 km.对故障件进行了断口分析、化学成分分析、力学性能检测、金相组织及硬度检验.结果表明,轴承盖螺栓属氢脆断裂.对库存件进行了氢含量检测,发现氢含量过高.提出了改进建议,取得了良好的效果.     

一种新型的节能空调装置--介绍复合末端机组(FC+UWSHP)与空气热源热泵冷/热水机组(ASHP)合并运行的系统

本文所介绍的新型空调系统是一种想法很巧妙的节能空调系统。它由单元式水热源热泵机组(ＵｎｉｔａｒｙＷａｔｅｒＳｏｕｒｃｅＨｅａｔＰｕｍｐ)与风机盘管二者组合而成的末端装置和空气热源热泵冷 /热水机组、蓄热槽等构成。本系统由高砂热学公司开发 ,已完成这方面的实验验证 ,并在东京电力公司的暖通空调技术展示中心展出。经过进一步的技术完善以后 ,可以成为一种有竞争力的空调系统。1　单元式水热源热泵机组 (ＵＷＳＨＰ)的原理单元式水热源热泵是一种房间空调器。可做成窗台下立式和吊顶式 (图 1 )等。它是一种整体型机组 ,制冷机在…     

多时滞Lotka-Volterra互惠系统周期正解的存在性

用重合度理论研究具时滞非自治Lotka-Volterra互惠系统，获得了周期正解的存在性，推广了Gopalsamy及He(1997)的结果。