蓄热式加热炉的空燃比控制

针对蓄热式加热炉具有多变量、时变、非线性、耦合、大惯性和纯滞后等特点,当前时于蓄热式加热炉的空燃比控制主要还是人工操作完成的问题,通过对蓄热式加热炉空燃比变化这一复杂的工业过程的分析,提出了一种蓄热式加热炉空燃比控制方法,设计了一个基于智能的空燃比控制系统.用无辨识自适应方法预测热值,用模糊神经网络预测烟气残氧量,解决...     

Robust H-infinity control for uncertain discrete-time Markovian jump systems with actuator saturation

The design of robust H-infinity controller for uncertain discrete-time Markovian jump systems with actuator saturation is addressed in this paper. The parameter uncertainties are assumed to be norm-bounded. Linear matrix inequality (LMI) conditions are proposed to design a set of controllers in order to satisfy the closed-loop local stability and closed-loop H-infinity performance. Using an LMI approach, a set of state feedback gains is constructed such that the set of admissible initial conditions is enlarged and formulated through solving an optimization problem. A numerical example is given to illustrate the effectiveness of the proposed methods.     

基于身份的粮油交易系统安全认证的研究

安全问题成为制约粮油交易健康发展的中心问题。粮油交易中如果企业或个人因事务繁忙,委托代理人与另一方进行签名即代理签名以进行粮油交易,并且为了对本单位人事关系或将来可能的人事变化保密,提出一种新的基于身份和双线性映射的匿名代理签名,以此完善粮油交易系统安全认证体系的功能。     

Fault tolerant control for singular systems with actuator saturation and nonlinear perturbation

In this paper, the problem of robust fault tolerant control for a class of singular systems subject to both time-varying state-dependent nonlinear perturbation and actuator saturation is investigated. A sufficient condition for the existence of a fixed-gain controller is first proposed which guarantees the regularity, impulse-free and stability of the closed-loop system under all possible faults. An optimization problem with LMI constraints is formulated to determine the largest contractively invariant ellipsoid. An adaptive fault tolerant controller is then developed to compensate for the failure effects on the system by estimating the fault and updating the design parameter matrices online. Both of these two controllers are in the form of a saturation avoidance feedback with the advantage of relatively small actuator capacities compared with the high gain counterpart. An example is included to illustrate the proposed procedures and their effectiveness.     

无线油水液位检测仪的研制

介绍了一种适用于海面溢油回收系统的基于无线数据传输的油水液位检测仪,该系统以ATmega128低功耗微处理器和无线收发芯片nRF905为核心,其采用的硬件电路设计与数据传输方式有效地提高了系统的可靠性,保证了海上溢油回收设备的全天候工作。     

小兴安岭7种松叶挥发油GC-MS数据的分析

用化学计量学方法分析小兴安岭7种松科植物松叶挥发油气相色谱-质谱(GC-MS)数据,为松叶挥发油的药理活性与其它的应用研究提供依据。(1)用直观推导式演进特征投影(heuristic evolving latent projections,HELP)法分辨重叠色谱峰,得各组分的纯色谱峰和质谱;(2)用正交投影法比较不同挥发油的GC-MS数据;(3)用峰面积归一化法确定各化合物的相对含量;(4)用主要化学成分进行聚类分析。7种松叶挥发油的化学成分为单萜、倍半萜及其衍生物和酯类化合物,按化学成分7种松叶挥发油可分为3类。     

Transient model of induction machine using rotating magnetic field approach

Most simulation models of electric machines use the coupled circuit approach, where the machine is considered as an electric circuit element with time-varying inductances (abc model) or with constant inductances (dq0 model). On the other hand, the rotating magnetic field approach, which considers the electric machine as two groups of windings producing rotating magnetic fields and can give insight into internal phenomena of the machines, has not yet received much attention in electric machines modeling, especially for machine transient analysis. Based on the rotating magnetic field approach, this paper presents a transient model of the induction machine including main flux saturation effect. Based on the direct computation of the magnetizing fluxes of all machine windings, the model represents instantaneous main flux saturation by simply introducing a main flux saturation factor. No iteration process is involved to incorporate the saturation effects. The model combines the advantages of the dq0 and abc models advantages, such as rapid computation time and nonsymmetrical conditions simulation, respectively. The simulation results and the experimental tests show advantages and verification of the model.     

Stabilization of linear systems with input delay and saturation—A parametric Lyapunov equation approach

This paper studies the problem of stabilizing a linear system with delayed and saturating feedback. It is known that the eigenstructure assignment‐based low‐gain feedback law (globally) stabilizes a linear system in the presence of arbitrarily large delay in its input, and semi‐globally stabilizes it when the input is also subject to saturation, as long as all its open‐loop poles are located in the closed left‐half plane. Based on a recently developed parametric Lyapunov equation‐based low‐gain feedback design method, this paper presents alternative, but simpler and more elegant, feedback laws that solve these problems. The advantages of this new approach include its simplicity, the capability of giving explicit conditions to guarantee the stability of the closed‐loop system, and the ease in scheduling the low‐gain parameter on line to achieve global stabilization in the presence of actuator saturation. Copyright © 2009 John Wiley & Sons, Ltd.     

品高艺自高——对中国油画创作的思考

中国油画艺术创作氛围的自由使得艺术理念多元化,这种情况下许多艺术家忽略了衡量艺术作品质量高低标准的品味及格调的要求,甚至摒弃了对自身对创作品格的高追求,从而深陷对单纯的视觉感官的满足于刺激,忽略文化素养的培养以及艺术家自身文学修养的提升。面对这种状况,文章以中外艺术家对"品"的不同理解为例对艺术家及其作品的格调进行了阐述。     

卫星遥感信息应用研究

近几年来,随着海洋石油运输业与航运业的迅猛发展,频繁发生的溢油事故造成了严重的环境污染、破坏着海洋生态系统。利用卫星遥感手段监视海面溢油可以达到覆盖面积大、快捷真实、同步连续的效果。通过分析溢油信息在遥感图像上的成像原理、各种卫星影像成像特点、采用遥感图像上溢油信息识别技术,卫星遥感监视海面溢油方法在多个实际溢油事故中得以成功应用。