科研管理项目管理系统设计与开发

信息化时代推动了我国科研水平飞速增长,为各行业、各领域提供先进的技术与设备支持,以此提升我国整体的GDP水平.文章认为在提升科研水平的过程中,科研项目管理系统起到举足轻重的作用,为科研活动的规范性、合理性与可行性提供了参考标准.     

Freely Tailorable Yolk-Shell Encapsulation: Versatile Applications in Ultralow-k Dielectric,Drug Delivery Systems,and Catalysts

Herein, a facile, controllable, and versatile method is reported to prepare monodisperse yolk-shell and yolk-multishell silica nanoparticles (NPs) with mesoporous shells by a novel selective etching strategy. The mechanism of selective etching based on fluoride-silica chemistry is investigated in detail and thus provides a fundamentally novel principle for the fabrication of yolk-shell NPs. Specifically, this unprecedented and versatile synthesis strategy can be used to encapsulate essentially any silica-based, carbon-based, metal, metal oxide, or other possible NPs. Noteworthy is that most of the yolk-shell mesoporous silica (mSiO₂) NPs are prepared for the first time. To demonstrate the major structural and compositional advantages of the designed yolk-shell NPs, their applications in the fields of ultralow-dielectric constant (k) materials, drug delivery systems, and catalysts were explored. In detail, the lowest k value of the prepared yolk-shellordered mesoporous silica@mSiO₂/fluorinated polybenzoxazole composite films is 2.02; The obtained yolk-shell mSiO₂/C@mSiO₂/C NPs possess high hydrophilicity and pH-responsive sensitivity; The conversion of the catalytic reaction of the designed magnetic yolk-shell hollow Fe₃O₄@SiO₂/Au@mSiO₂ NPs at 20 min is 97% with a high conversion rate (92%) and recyclability even after 10 reuses. This innovative work lays a solid foundation for freely tailorable yolk-shell encapsulation and will greatly stimulate more efforts devoted to relevant research and development.     

A Solenoid-Type Inductor Fabricated by MEMS Technique

A solenoid-type inductor for high frequency application is realized using a micro-electro-mechanical systems (MEMS) technique.In order to achieve a high inductance value and Q factor,UV-LIGA,dry etching technique,fine polishing and electroplating technique are adopted.The dimensions of the inductor are 1500μm×900μm×70μm,having 41 turns with a coil width of 20μm separated by 20μm spaces and a high aspect ratio of 3.5∶1.The maximum measured inductance of the inductor is 6.17nH with a Q factor of about 6.     

块三对角线性方程组的可扩展块分割奇偶约化并行近似求解方法

文章对于一类严格块对角占优的块三对角线性方程组提出一个可扩展的块分割奇偶约化并行近似求解方法（PBOERA方法）。计算量减少到O（nm^2）＋O（m^3logm）;通信复杂度为常数。本方法在上海大学分布式并行计算机“自强3000”上使用64个节点进行了运行。得到线性加速比,并行效率达到90％以上。     

MEMS波长可调谐激光器及其进展

论述了MEMS波长可调谐激光器及其进展。介绍了几种不同类型的波长可调谐激光器,如基于表面微机械反射镜的MEMS可调谐激光器、基于深腐蚀圆形反射镜的MEMS可调谐激光器、基于闪耀光栅的MEMS可调谐激光器、基于阵列集成的MEMS可调谐DFB激光器和VCSEL基MEMS可调谐激光器。     

The effects of PMD and PDL on the performance of OOK and DPSK systems

Using multiple importance sampling （MIS） technique, the optical communication system performance affected by polarization-mode dispersion （PMD） and polarization-dependent loss （PDL） is simulated numerically. The power penalties and system outage probabilities are obtained for optical communication systems with on-off keying （OOK） or differential phase shift keying （DPSK） modulation. The simulation results show that DPSK always performs better than OOK. When the system has moderate PDL （about 1.5 dB）, it is necessary to compensate effectively the fiber PMD in order to enhance the system tolerance to the PMD and PDL. However, the efficiency of PMD compensation will degrade rapidly when the PMD of the whole optical link drops into the low value.     

Cramer–Rao bound and minimum variance unbiased estimator for joint sampling clock offset and channel taps in MC‐CDMA systems

Exact closed‐form expressions of the Cramer–Rao bound (CRB) for joint sampling clock offset and channel taps are obtained in multi‐carrier code division multiple access systems. CRB is undoubtedly the most well known variance's bound to determine. It provides a benchmark against which we can compare the performance of any unbiased estimator. Furthermore, minimum variance unbiased (MVU) estimator for these parameters is proposed. Moreover, maximum likelihood (ML) and least‐squares estimators for joint sampling clock offset and channel taps are presented. Best linear unbiased estimator is also introduced just for channel taps. The performances of the estimators are compared through simulation results with the proposed CRB. Our results show the better performances of MVU and ML estimators with more computational complexity compared with the others. Copyright © 2008 John Wiley & Sons, Ltd.     

Autonomous and teleoperation control of a mobile robot

The present work proposes an autonomous tracking control system and a control structure to combine autonomous and teleoperation commands in a bicycle-type mobile robot. This compounded operation renders great flexibility to the control system of the mobile robot. For autonomous operation, a simple tracking controller that includes compensation of the robot dynamics is developed. This tracking control system is proved to be stable in the sense that it asymptotically reaches the tracking objective. Teleoperation with visual access to the robot’s workspace is integrated via a joystick with the autonomous operation of the robot. Simulations and experimental results on a prototype robot show the feasibility and performance of the proposed control system.     

美军卫星通信系统的发展及其技术研究

随着信息技术的快速发展,美军为满足未来战争需要不断地规划研发新的通信卫星系统。文中主要讨论了美军卫星通信系统的现状和未来发展,归纳了相关的关键技术,最后总结了目前卫星通信的重要性并指出了今后研究的方向。研究美军在这一领域的新发展和成果,目的是为我国构建空间信息网络奠定必要的基础。     

Arithmetic Expression Evaluations with Membranes

Arithmetic operations and expression eval- uations are fundamental in computing models. This paper firstly designs arithmetic membranes without priority rules for basic arithmetic operations, and then proposes an algo- rithm to construct expression P systems based on several of such membranes after designing synchronous and asyn- chronous transmission strategies among the membranes. For any arithmetic expression, an expression P system can be built to evaluate it effectively. Finally, we discuss differ- ent parallelism strategies through which different expres- sion P systems can be built for an arithmetic expression.