Thermodynamic reassessment of the Cd−Zn system

The Cd−Zn system has been thermodynamically reassessed with the CALPHAD method by combining more recent experimental data, in particular the activities of zinc in the liquid phase. A good agreement is obtained between the calculated and experimental thermodynamic parameters as well asphase boundaries.     

A THERMODYNAMIC INVESTIGATION ON SPINODAL DECOMPOSITION BOUNDARY IN Cu－Ti ALLOYS

ＡＴＨＥＲＭＯＤＹＮＡＭＩＣＩＮＶＥＳＴＩＧＡＴＩＯＮＯＮＳＰＩＮＯＤＡＬＤＥＣＯＭＰＯＳＩＴＩＯＮＢＯＵＮＤＡＲＹＩＮＣｕ－ＴｉＡＬＬＯＹＳ￥ＷｅｉＹｉｎｇｈｕｉ；ＷａｎｇＸｉａｏｔｉａｎ（ＩｎｓｔｉｔｕｔｅｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎ...     

Consensus of Fractional‐Order Uncertain Multi‐Agent Systems Based on Output Feedback

This paper is devoted to the consensus protocol design for a set of agents with fractional‐order uncertainty dynamics where the fractional order α satisfies 0 < α < 2. For multi‐agent systems (MASs) with fixed undirected topology, a distributed static output feedback protocol is proposed with an undetermined system matrix. Based on model transformation and fractional‐order stability theory, sufficient conditions are derived to ensure the consensus of MASs in terms of linear matrix inequalities (LMIs). Finally, a simulation example is employed to validate the effectiveness of the proposed consensus protocol.     

GPS-北斗双模目标定位系统的设计

为解决目标远程监控的要求,设计了GPS-北斗双模目标定位系统,充分利用两种导航系统的优势,提高目标的定位精度。本文在阐述该系统工作原理的基础上,重点给出了系统的具体设计方法。     

广义系统的时滞依赖静态输出反馈控制

针对一类不确定线性广义时滞系统,给出了静态输出反馈控制器的设计方法.首先基于标称广义时滞系统的稳定条件,以受限线性矩阵不等式形式,给出闭环广义时滞系统正则、无脉冲且渐近稳定的充分条件,同时利用受限矩阵不等式的可行解给出静态输出反馈控制律的一个参数化表示;其次,利用矩阵的正交补,把求受限线性矩阵不等式的可行解问题转化为求严格线性矩阵不等式(LMIs)的可行解;最后应用数值实例说明了所给方法的有效性和正确性.     

基于光伏电池输出特性的MPPT算法研究

为了寻找更好的实现光伏发电系统最大功率点跟踪控制方法,基于单个光伏电池的物理特性建立了太阳能光伏电池阵列的Matlab仿真模型,分析了太阳能光伏电池阵列所具有的随着光照强度和温度不同而变化的P-U和I-U非线性特性.基于光伏电池的动态特性,在最大功率点跟踪算法的设计中增加一个电流监测回路,并结合自寻优技术对电导增量法进行改进,提出了一种自适应变步长寻优算法.仿真结果表明,该算法能够快速准确的跟踪最大功率点.     

Output feedback variable structure control of uncertain linear systems in the presence of actuator dynamics

A new output feedback variable structure control scheme is developed based on a novel passivity idea. This scheme may practically stabilize a class of higher‐relative‐degree uncertain linear systems, and realize output tracking and disturbance attenuation as well. The controller is composed of linear filters and a single relay, without employing real‐time exact differentiators. Under this framework, we also explain how actuator dynamics affect the closed loop behavior. A simulation example shows the simplicity and efficiency of this method. Copyright © 2009 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society     

热处理非晶态Ni-P合金镀层的晶化过程

运用电沉积的方法在45钢基体上制备Ni-P合金镀层,使用差示扫描量热法(DSC)和热重法(TG)分析非晶态NiP合金镀层在20℃/min加热速率下的热效应和质量变化。在300℃和400℃分别对镀层进行0,15,30,45,60,75min的热处理,采用扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)、显微硬度计对镀层进行表征。结果表明:Ni-P合金镀层在加热过程中的放热峰出现在284.8℃处,镀层的质量和元素组成稳定;晶化过程经历了非晶态、亚稳态NiP和Ni5P2、稳定态Ni3P的转变;经过热处理后,镀层的显微硬度显著提高,最大值达1036.56HV,约为镀态的2倍;热处理态镀层的耐NaCl溶液腐蚀性能比镀态有所下降,但两者都比45钢基体好。