P2P模式的系统结构研究

本文首先介绍了什么是P2P和它的基本运作模式。详细阐述P2P模式的主要形式及其相应的系统结构。     

高声压级驻极体噪声传感器的改进研究

为满足航天对170dB高声压级、1dB小频率响应平坦度噪声传感器的应用需求,采用动态范围和自由场频率响应较宽的1/4英寸驻极体传声器为声压敏感元件,用专用场效应管电路对传声器进行阻抗变换和信号放大,并对传统结构优化改进。经过测试和环境试验,传感器在135~170dB高声压级动态范围内幅值线性度达到了±0.5%以内,20Hz~8kHz频率响应平坦度达到了0.5dB。传感器通过了国家权威机构的鉴定检验,证实了这种传感器在火箭飞行试验中应用的可行性。     

Expectations for Crater Size and Photometric Evolution from the Deep Impact Collision

The NASA Discovery Deep Impact mission involves a unique experiment designed to excavate pristine materials from below the surface of comet. In July 2005, the Deep Impact (DI) spacecraft, will release a 360 kg probe that will collide with comet 9P/Tempel 1. This collision will excavate pristine materials from depth and produce a crater whose size and appearance will provide fundamental insights into the nature and physical properties of the upper 20 to 40 m. Laboratory impact experiments performed at the NASA Ames Vertical Gun Range at NASA Ames Research Center were designed to assess the range of possible outcomes for a wide range of target types and impact angles. Although all experiments were performed under terrestrial gravity, key scaling relations and processes allow first-order extrapolations to Tempel 1. If gravity-scaling relations apply (weakly bonded particulate near-surface), the DI impact could create a crater 70 m to 140 m in diameter, depending on the scaling relation applied. Smaller than expected craters can be attributed either to the effect of strength limiting crater growth or to collapse of an unstable (deep) transient crater as a result of very high porosity and compressibility. Larger then expected craters could indicate unusually low density (< 0.3 g cm⁻³) or backpressures from expanding vapor. Consequently, final crater size or depth may not uniquely establish the physical nature of the upper 20 m of the comet. But the observed ejecta curtain angles and crater morphology will help resolve this ambiguity. Moreover, the intensity and decay of the impact “flash” as observed from Earth, space probes, or the accompanying DI flyby instruments should provide critical data that will further resolve ambiguities.     

TiAl系金属间化合物球型预合金粉末制备及粉末冶金工艺研究

成功制备了Ti-46Al-2Cr-2Nb-0．2B-0．1W（原子分数）球型预合金粉末，并对粉末的特性进行了研究。在随后的粉末冶金技术研究中，运用热等静压技术得到了组织细小、均匀的粉末TiAl系金属间化合物，但材料的伸长率很低。经热处理后，材料的伸长率达到了2．5％。     

用小角度测量仪校准合象水平仪的不确定度问题探讨

介绍了微分筒式小角度测量仪的构造及测量原理 ,对使用该小角度测量仪校准合象水平仪时的测量不确定度进行了分析计算 ,指出使用微分筒法校准合象水平仪准确度高且操作方便。     

Estimation of the solar proton spectrum in the GLE70 event

The GLE event on December 13, 2006 as observed by network station neutron monitor data is investigated (is considered). The GLE energetic spectrum suggested for this event is estimated taking into account the primary differential spectrum of galactic cosmic rays, coupling coefficients and integral multiplicities of concrete detectors at different latitudes and levels of observation. It is noted that the additional increase of solar protons is also manifested in the ionization chamber ASK-1 data at the Yakutsk station.     

多层铜布线CMP工艺的优化研究

集成电路多层铜布线平坦化中,CMP工艺参数的配置是决定抛光表面状态和平坦化程度的重要因素。本文研究了碱性介质下铜CMP机理,深入分析了CMP系统中影响抛光表面状态的诸多工艺因素。在此基础上设计了多层铜布线CMP工艺的优化实验,有效地解决了划伤,蚀坑等表面缺陷问题,实验测定表面粗糙度数据较为理想,获得了良好的实验效果。     

基于AHP-SPA方法的民机修理级别确定综合分析模型

民机保障性分析中的重要内容之一是修理级别分析(Level of Repair Analysis,LORA),现有的修理级别分析模型没有基于民机维修保障体制的特点综合考虑各类影响修理级别的因素。文章综合考虑修理级别分析的技术指标、经济指标和商业指标,将层次分析法(Analytical Hierarchy Process,AHP)与集对分析法(Set Pair Analysis,SPA)结合起来,建立民机修理级别分析综合评价模型,以实施经济性修理级别分析。并通过实例对AHP-SPA综合分析模型进行验证,表明了该模型的可行性,因此该文章的理论模型可为民机制造商和航空公司在修理级别确定方面提供理论参考和技术支持。     

三年上水平进程中廊坊市夜经济发展路径研究

2010年河北省召开了发展夜经济工作会议,把提高夜消费水平、做强夜经济作为当前扩大内需的一项重要工作来抓。夜经济是城市经济发展到特定阶段的反映,夜经济已成为一个城乡经济框架中的重要组成部分。在城镇建设三年上水平进程中,廊坊市城镇建设已经开始进入系统提升城市功能和品质,塑造城市特色上水平、出品位、生财富阶段。如何让夜经济发展成为廊坊市三年上水平进程中的有力推动者,本文就这一问题展开研究,进而提出相应的建议。