Minimum switching control for adaptive tracking

The switching adaptive control method has been used for quite a few years to solve the adaptive stabilization and model reference adaptive control problems. However, a serious problem with the switching control method is that the number of ‘candidate’ controllers can potentially be very large, especially for multi‐input–multi‐output systems. In this paper, we consider a class of minimum‐phase multi‐input–multi‐output plants with some mild compactness assumptions. Given any polynomial reference input, we provide a switching control law which guarantees exponentially stability of the closed‐loop system with exponential tracking performance. The main contribution of the paper is that we give the minimum number of candidate controllers required for switching. In particular, the number is equal to 2 for single‐input–single‐output plants (one for each sign of the high‐frequency gain), and is equal to 2^m for m‐input–m‐output plants. That is, the number is independent of the degree and the relative degree of the plant. Copyright © 2006 John Wiley & Sons, Ltd.     

自适应相位制中波同步广播及现场试验

在本试验中，采用智能同步广播激励器和ＣＣＴＶ传输的１ＭＨｚ标频，实现了中波同步广播同频保护率趋于０ｄＢ．并提出了自适应相位跟踪同步的概念。     

高架桥中异形板裂缝的分析与加固

从分析某高架桥中异形板板底裂缝的特点及成因着手 ,对设计与施工工艺诸方面提出防止裂缝的对策和对裂缝进行加固的全过程。     

平面Z-型软磁铁氧体频率特性的研究

研究分析了Co2Z材料显微结构与磁性能的关系,在普通铁氧体工艺中引入预磁化处理方法,并适当控制二次再结晶现象,成功地研制出高性能的Co2Z型宽频材料,Z-型铁氧体材料的共振频率可达1.8GHz以上,截止频率在1GHz附近,起始磁导率在8-13之间,介电常数相对较低(ε'<30)。     

采用信息融合技术的IR／MMW复合导引头的目标跟踪

从误差测量环节入手，基于IR／MMW双模结构，采用信息融合处理技术提高其估计跟踪精度，最终达到降低制导误差，提高武器性能的目的，仿真结果验证了该方法的有效性。     

膨胀水泥浆体系在苏丹1/2/4区块水平井固井中的应用

随着苏丹1／2／4区块的深入开发，为了加快开发主力油层，提高原油产量，降低钻井成本，GNPOC在此区块布置水平井开发任务。所开发的区域主要分布于Heglig，Munga，Simbir，Bamboo区块，油层所在是Zaqar和Bentiue地层。此层位具有高渗透，地层温度高，易塌、气窜等复杂问题，尤其是Heglig和Munga地区井壁坍塌严重。为此，根据地质资料、井身结构和对水平井注水泥的技术要求，科学合理设计施工工艺，优选出适合此地区固井施工的冲洗液和隔离液，特别是经过努力实践，开发出了新型膨胀水泥浆体系，此体系具有高强度、低失水、无析水、防气窜之功效。结合使用哈里伯顿CPT—Y4大功率固井车，精确计量和自动密度控制，该体系水泥浆目前已在7口水平井施工中得以应用，均为优质井。现正在被大量使用，此体系的开发，解决了该固井技术难题，创造了中国固井在海外首次水平井作业一次成功的历史记录，具有较高的经济和社会效益。     

南水北调中线水源工程的突变多准则评价

应用突变多准则评价法对南水北调中线水源工程项目的多方案比选作出评价决策。该方法为专家决策系统提供一种数学方法 ,以便用计算机实现多目标、多层次、多方案的评价决策。     

Shallow hydrogen-induced donor in monocrystalline silicon and quantum wires

Electrical and optical properties of bistable shallow donors in monocrystalline silicon, which are introduced by proton implantation followed by annealing at 450 °C, have been studied. The temperature dependences of equilibrium and non-equilibrium carrier concentration and relaxation kinetics were investigated. IR absorption lines of bistable shallow donor electronic excitations were detected. The obtained experimental data demonstrate that the bistable shallow donors can be identified as quantum wire defect nanoclusters.     

频域吸收边界条件的构造理论

在频域中推导了适用于差分类数值方法的吸收边界条件的构造方法，并通过选取不同参数导出了几种现有的吸收边界条件。在计算了一般形式的吸收边界条件的反射系数之后，提出了一种简单实用的自适应吸收边界条件。