晶体生长过程建模及解耦控制

晶体生长过程中其直径的控制是通过调节生长速度和热场温度而实现的.控制系统是一个双入双出系统,输入输出之间存在耦合关系.本文采用前馈补偿解耦的方法,实现了单晶炉生长控制中的解耦控制,并通过仿真及实验证明了方法的有效性.     

海洋平台的时域低阶建模与主动控制研究

以海洋平台为对象, 开展时域低阶建模与主动控制的研究. 首先采用OKID(observer/Kalman filter identification)辨识方法, 根据系统的输入和输出时间历程数据计算出系统的Markov参数, 然后采用特征系统实现方法(eigensystemrealization algorithm, ERA)建立起一个阶数较低的系统状态空间模型, 随后基于该低阶模型采用LQG (linear quadratic Gaussian)控制方法进行控制律的设计, 最后将该控制律引入到系统的有限元模型中进行反馈闭环控制, 验证控制律的有效性. 数值仿真结果显示, 所给方法是有效和可行的.      

Enhanced Multiparty Controlled QSDC Using GHZ State

Recently, Gao et al. [Opt. Commun. 283 (2010) 192] pointed out that Wang et al.'s multiparty controlled quantum secure directcommunication (CQSDC) protocol [Opt. Commun. 266 (2006)732] has the information leakage problem and proposed an improvedprotocol. However, in the improved protocol, due to the introductionof an additional random sampling to avoid the weakness, the qubitefficiency is decreased. By introducing the base changing techniqueto the random sampling in Wang et al.'s protocol, this study overcomesthe information leakage problem and provides a better qubit efficiency.     

基于i-motif的生物医学应用纳米系统:pH成像、药物控释和肿瘤诊疗

I-motif作为一种新型pH敏感元件,因其在不同pH条件下可以进行快速的构象转变,以及具有自动化合成、优异的生物相容性和灵活的功能化整合等优点,在生物医学领域引起了广泛的关注和研究热潮.该文介绍了i-motif的基本性能,综述了基于i-motif的纳米系统在细胞pH成像、pH控制的药物释放和pH响应型肿瘤诊疗一体化等...     

Decay properties of Markovian bulk-arrival and bulk-service queues with state-independent control

We consider decay properties regarding decay parameter and invariant measures of Markovian bulk-arrival and bulk-service queues with state-independent control. The exact value of the decay parameter, denoted by λz, is firstly revealed. A criterion regarding ）λz-recurrence and λz-positive is obtained. The corresponding λz-subinvariant/invariant measures and λz-subinvariant/invariant vectors are then presented.     

激光诱导击穿光谱脉冲激光功率锁定的研究

激光诱导击穿光谱(laser-induced breakdown spectroscopy,LIBS)在煤质在线监测方面展现了突出的应用前景和研究价值。针对该技术在实际应用中会由于脉冲激光功率起伏导致的长期测量稳定性差的问题,建立了闭环负反馈式脉冲激光功率锁定装置,采用激光功率负反馈信号控制和锁定Nd∶YAG激光器输出功率。实验研究了不同分光比例脉冲激光器锁定在设定输出功率,同一分光比例激光器锁定在不同输出功率以及长时间运行时的功率锁定。结果表明,不同的分光比例对激光输出功率的锁定效果影响不大,分光比例越小,稳定速度越快;同一分光比例实现激光脉冲功率不同预设值的锁定以及在长时间运行时,采用此装置进行功率锁定后,激光输出功率处于预设区间内,RSD值由自由运行时的2.4%降低至1.1%。     

Generation of minimally persistent circle formation for a multi-agent system

In this paper, two methods of generating minimally persistent circle formation are presented. The proposed methods adopt a leader-follower strategy and all followers are firstly motivated to move into the leader＇s interaction range. Based on the information about relative angle and relative distance, two numbering schemes are proposed to generate minimally persistent circle formation. Distributed control laws are also designed to maintain the desired relative distance between agents. The distinctive features of the proposed methods are as follows. First, only 2n - 3 unilateral communication links for n agents are needed during the circle formation process and thus the communication complexity can be reduced. In addition, the formation topology is kept fixed for the whole motion and achieves a self-stability property. Finally, each follower keeps a regualr interval with its neighbors and the formation converges to a uniform circle formation. Simulation results are also provided to demonstrate the effectiveness of the proposed methods.     

基于专家－模糊PID的通用温度控制系统研究

为了解决温度控制系统易受外界干扰、自身参数时变不确定以及控制难度大等问题, 采用了模糊PID控制算法结合专家判断, 组成专家－模糊PID控制器的方法来控制温度. 将该方法应用于通用智能温度控制器中, 调试运行结果表明: 该方法解决了常规PID适应性差、不能在线进行参数自整定的问题, 不仅具有PID控制精度高的优点, 同时具有良好的动、静态特性, 可满足在通用智能温度控制器中的应用     

Weibull分布的生鲜农产品库存控制

研究基于Weibull分布的生鲜农产品在通货膨胀和延期支付下库存最优订货策略,用控制理论和系统优化方法,根据生鲜农产品的特点,设定农产品自然腐烂率为常数,根据实际中市场需求呈Weibull分布情况,建立了基于二维Weibull分布的库存控制模型.探讨了通货膨胀和延期支付对Weibull分布下最优订货量和最小库存成本的影响.以蔬菜批发市场实例,论证了该方法的可行性,该研究成果为生鲜农产品库存控制提供了一种新的方法,具有一定的理论指导和实际借鉴作用.