Microstructure and Fractural Morphology of Cobalt-based Alloy Laser Cladding

1　IntroductionCobalt basedalloyiswidelyusedingasturbineair craftenginesandvalvespumpshaftsofpressurevessels[1,2 ] ,duetoitshighflowstressesandoutstandingresistancetooxidationandwearuptotemperaturesclosingtoitsmeltingpoint.Thehighsolidificationrateoflasercladdingtendstoresultinfinemicrostructures ,non equi libriumphasesandsupersaturatedsolidsolutions ,whichleadtohighhardnessandwearandcorrosionresi stance[3 -5] .However,crackingfrequentlyappearsinthelasercladdinglayerwhichlimitstheuseofthissurf…     

嵌入式OS-uClinux软件开发环境的建立及应用程序开发模式

本文介绍了在mcf5272嵌入式硬件开发板基础上如何移植uClinux操作系统以及开发用户应用程序的基本模式。     

Determination Of The Phase Current Waveform For A Disc‐Type Axial‐Flux Wheel Motor

An optimal design of the driving current pattern for a disc‐type axial‐flux brushless DC wheel motor of an electric vehicle is proposed in this paper. The electro‐magnetic dynamic model of the motor is established with magnetic circuits, describing the relationship between the output torque and excitation current. The optimal current pattern, in terms of magnitude and phase angle, is then obtained by maximizing the output torque with respect to the rotor shift. Compared with the traditional three‐phase‐on current pattern of fixed 120–degree phase shift, both the average torque and efficiency with the driving current of an optimal advanced switching angle are seen to be improved under various loading conditions. The motor performance with the optimal driving waveform is simulated and verified by experiments.     

采用UDP在Internet上传输MPEG-4视频码流方案

给出了MPEG－4视频码流在Internet上传输的码流结构，传输过程中采用的码率控制方案，并给出了进行差错控制的方法，模拟试验表明，采用本文提出的方案比较有效地降低了传输过程的时延。     

基于Linux的蓝牙系统核心协议栈的设计与实现

本文设计与实现的基于Linux平台的Bluetooth核心协议栈主要由四个模块组成：服务发现协议SDF模块，逻辑链路控制与适配协议L2CAP模块，串行线路模拟协议RFCOMM模块和主机控制接口HCI模块。在本核心协议栈的设计过程中，始终将提高整个协议栈的执行效率作为第一目标。为提高协议栈的效率，对协议栈进行了设计优化，采用了状态自动机、散列技术、缓冲机制、开放式平台、硬件模拟技术等一些先进技术。     

Output feedback control design for strict-feedback stochastic nonlinear systems under a risk-sensitive cost

In this note, we study the problem of output-feedback control design for a class of strict feedback stochastic nonlinear systems. Under an infinite-horizon risk-sensitive cost criterion, the controller designed can guarantee an arbitrary small long-term average cost for arbitrary risk-sensitivity parameter and achieve boundedness in probability for the closed-loop system, using the integrator backstepping methodology. Furthermore, the controller preserves the equilibrium at the origin of the nonlinear system.     

A CMOS-MEMS mirror with curled-hinge comb drives

A micromirror achieves up to /spl plusmn/4.7/spl deg/ angular displacement with 18 Vdc by a comb-drive design that uses vertical angled offset of the comb fingers. Structures are made from a combination of CMOS interconnect layers and a thick underlying silicon layer. Electrical isolation of the silicon fingers is realized with a slight silicon undercut etch, which disconnects sufficiently narrow pieces of silicon under the CMOS microstructures. The 1 mm by 1 mm micromirror is made of an approximately 40 /spl mu/m-thick single-crystal silicon plate coated with aluminum from the CMOS interconnect stack. The mirror has a peak-to-peak curling of 0.5 /spl mu/m. Fabrication starts with a conventional CMOS process followed by dry-etch micromachining steps. There is no need for wafer bonding and accurate front-to-backside alignment. Such capability has potential applications in biomedical imaging, optical switches, optical scanners, interferometric systems, and vibratory gyroscopes.     

设计模式中的面向对象原则及其子模式

在[Gamm95]中总结并提出了面向对象软件设计中非常重要的23个设计模式，这些模式尽管形态各异、目的不同，但它们都体现了相同的几个面向对象原则。该文讨论了这些面向对象的原则并对隐含在设计模式中的几个“子模式”进行了分析和总结。     

基于足迹采样的运动编辑

针对人体两足动画提出一种基于足迹采样的运动编辑算法．足迹很好地描述了两足动画中必须满足的时空约束，通过调整足迹的位置与朝向来编辑两足动画是一种较为自然、直观的交互方式．为有效、快速地生成编辑后的动画，采用一种实时的逆向运动学算法求解两足动画中的支撑脚约束，然后使用层次B样条技术构造偏移映射完成编辑．为了便于逆向运动学算法的求解，提出基于采样的方法来计算质心轨迹．     

油压减振器计算机辅助优化设计系统的研制

为了优化可调式线性油压减振器的性能，在白行研制的广义优化设计支持平台上对其线性阻尼系统进行广义优化建模与设计，并基于MATLAB开发了动态仿真软件包，对该广义优化设计结果进行分析与评价．样机开发与试验研究结果表明：文中建立的广义优化设计数学模型和动态仿真模型是准确的，研制的计算机辅助优化设计系统高效、实用．