2K-H型人字齿周转轮系的免组装设计与成型

为了解决人字齿周转轮系加工、装配的难题,提出利用3D打印技术制造免组装人字齿周转轮系的新工艺。通过理论推导,建立变位系数、齿侧间隙与齿轮基本参数之间的关系。利用建立的关系式,对行星轮进行负变位,设计具有微量齿侧间隙的2K-H型人字齿周转轮系。利用熔融沉积成型实验平台使设计的人字齿周转轮系成型,成型后的人字齿周转轮系齿轮啮合传动正常,设计、制作相应辅件,将其装配成减速步进电机。结果表明,通过合适的间隙设计,可以利用3D打印技术实现人字齿周转轮系的免组装制造,为小尺寸、一体式人字齿周转轮系个性化定制提供了一种具有工业应用前景的全新解决方案。     

8Mbit／s数字电视系统的设计与实现

介绍了８Ｍｂｉｔ／ｓ数字电视系统的系统构成，给出了图象压缩编解码，声音压缩编解码和数据通信接口的实现方案，对系统中所采用的新缓存控制策略也作了分析。     

氦离子注入掺铈铌酸锶钡晶体平面光波导和它的光折变性质

室温下用2.8MeV氦离子注入在掺铈铌酸锶钡晶体上形成了平面光波导。用棱镜耦合法观察到了波导的暗模。计算的折射率分布表明在离子注入产生的损伤层中晶体的折射率减小，其中正常折射率减小约3．42％，反常折射率减小为2．55％。由PIPR方法拟合的波导中的折射率分布与TRIM’96给出的注入离子的密度分布基本一致。两波耦合实验表明离子注入可以延长折射率光栅的擦除时间。     

化学机械抛光工艺中的硅片背压力控制与优化

化学机械抛光（Chemical Mechanical Polishing,CMP）技术是最有效的晶圆全局平坦化技术,抛光头是CMP设备中最核心的部件之一,新一代抛光头的设计主要采用区域压力控制技术。硅片抛光质量不仅取决于抛光液,还取决于对硅片抛光压力的精确控制。在CMP抛光工艺过程中各腔室的压力设定值通常并非一致,而且由于柔性弹性隔膜的存在各腔室之间相互耦合。由于耦合现象的存在使得多区腔室压力控制变得复杂化,针对这一耦合现象本文提出了一种用于多区解耦的控制方法,并基于该方法对多腔室进行了系统辨识以及控制参数整定,最后进行了多腔室同时加压实验,实验结果表明该解耦控制方法的可行性以及正确性。     

Electrically conductor black zirconia ceramic by SPS using graphene oxide

The use of graphene as a component for developing electroconductive ceramic composites is being profusely studied. It is a very promising additive as it has excellent mechanical properties, high electrical and thermal conductivities, it is lightweight and its aspect ratio allows reaching percolation with low contents.In the particular case of zirconia, preparation of black coloured materials remains a challenge while many high added value applications are waiting for a solution. Graphene appears as a candidate for fulfilling all these requirements. In this work, 3Y–TZP/rGO composites were prepared by Spark Plasma Sintering Zirconia-rGO mixtures. Simultaneous sintering and in-situ reduction of graphene oxide opens a very interesting technological route for preparing this type of materials. The influence of graphene content on the electrical, mechanical and optical properties was studied. An rGO content as low as 0,29 vol% allows nanostructured black zirconia to be obtained but it has to be increased up to 1 vol% in order to reach electrical resistivity values <100Ωcm, required for electrodischarge machining.     

3G背景下网络信息安全形势综述

文章总结了2009年信息安全领域发生的各种重要事件。3G背景下，网络信息传播对政治、经济、社会，以及用户的个人生活都产生了深远的影响，网络信息安全问题需要各方面及时认真对待和防范。     

Size effect on the kinematic parameters of nanometer-thick bilayer films

The behavior of nanodimensional bilayer structures (plates) of finite length consisting of nanometer-thick crystalline Ni and Cu films has been studied by means of molecular dynamics simulation. The inter-atomic interactions were described within the framework of the embedded atom method. It is shown that, in the absence of an external action, the nanostructures perform mechanical oscillations with the amplitude and frequency determined by the length and thickness of the plate. The dependence of the parameters of oscillations of the nanodimensional structures on their dimensions is established. The results can be used in designing components of nanodevices for various applications.     

换热器传热特性的试验方法研究

本文提出了一种新的研究换热器传热特性的试验方法.按着传热的基本原理,应用最优化方法,得出可以同时准确的确定换热面两侧冷、热流体的对流换热规律.这种方法进一步发展和改进了 Wilson 方法.它可以进行多个末知参数的计算,有较高的计算精度.文中依据理论分析和应用实例测试,验证了该方法的数学可行性.     

Raman studies of semiconducting oxide nanobelts

Crystalline nanobelts of ZnO and SnO2 were prepared from a thermal evaporation of oxide powders inside an alumina tube in the absence of catalysts. Typical dimensions of the nanobelt samples ranged from approximately 10 to 100 microns in length, 30 to 300 nm in width, and 6 to 30 nm in thickness. Room temperature Raman spectra were obtained on pressed mats of nanobelt samples and compared with the corresponding spectra of the starting oxide powders and bulk materials. Collectively, our Raman data indicated that the as-prepared nanobelt samples used in this study were oxygen deficient. Upon annealing at 900 degrees C in flowing oxygen for 1 h, the nanobelt samples exhibited Raman features that corresponded to those expected in respective bulk semiconducting oxides. The dimensions of the nanobelts were a bit too large to expect significant quantum size effects on the phonon structure similar to those observed in carbon nanotubes and short-period semiconductor superlattices.     

全球宽带接入市场发展趋势

从用户数持续快速增长、宽带用户数最多的国家和地区、宽带用户增量、宽带用户增长率以及宽带业务普及率等5个方面阐明了全球宽带接入市场的总体情况。分析指出宽带接入技术发展趋势．DSL在近两年内仍将占据主流地位。介招了宽带增值业务发展情况。