用于安全稳定控制的高压直流极闭锁判据

交直流并联运行电网中直流极闭锁后引起的安全稳定问题十分突出，如何正确判别直流极闭锁是安全稳定控制系统研究中的重要课题。采用数值仿真方法分析了直流极闭锁对电力系统稳定的影响，指出稳定控制装置必须正确、快速地判出不同形式的直流极闭锁。通过研究直流极闭锁的电气量特征以及直流控制保护系统的动作行为，提出了可靠的直流极闭锁综合判据，并进行了详细的阐述。通过介绍中国南方交直流混联电网安全稳定控制系统核心部分———高肇直流输电安全稳定控制系统，进一步论述了研究直流极闭锁判据及直流极闭锁后稳定控制的重要性。     

Improvement of levitation characteristics in a magnetic bearing system using HTSC‐permanent magnet hybrid structure

Magnetic bearing using pinning force of a permanent magnet and a high‐temperature superconductor has been developed. Additional permanent magnet is introduced to increase the levitation force of the magnetic bearing. In this hybrid magnetic bearing system, levitation force is mainly given by the repulsive force of the permanent magnets, and stability for the lateral direction is given by pinning force of the superconductor. The experimental device is developed. A ring‐type superconductor and a bulk one are examined. Levitation characteristics of the hybrid magnetic bearing are measured. The bulk superconductor shows better characteristics of both levitation and lateral stability than the ring one. Levitation force of the hybrid system becomes about twice as large as that of the nonhybrid one. Although, the repulsive force of the permanent magnet decreases the lateral stability of the system, its influence becomes small by choosing an adequate position of the permanent magnets and the superconductor. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(1): 71–77, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10350     

Performance prediction of a hybrid‐excitation synchronous machine with axially arranged excitation poles and permanent‐magnet poles

This paper presents a method of predicting the steady‐state performance of a new hybrid‐excitation synchronous machine (HESM) theoretically. The field pole of this HESM is axially divided into two parts; one is an excitation part and the other a permanent‐magnet (PM) part. A nonlinear equivalent circuit, which can include the saliency of the rotor and the magnetic saturation due to the iron core, is derived. Based on this equivalent circuit, the steady‐state performance of the HESM is calculated, and the results are confirmed through experiments. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 150(2): 43–49, 2005; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20033     

Inference and learning in hybrid probabilistic network

This paper proposed a novel hybrid probabilistic network, which is a good tradeoff between the model complexity and learnability in practice. It relaxes the conditional independence assumptions of Naive Bayes while still permitting efficient inference and learning. Experimental studies on a set of natural domains prove its clear advantages with respect to the generalization ability.     

天然彩色棉产品抗紫外线处理的探讨

介绍了天然彩色棉的应用现状以及对其进行抗紫外线处理的现实意义，探讨了抗紫外线处理的方法和检测手段，并结合初步的实验提出在天然彩色棉产品上进行抗紫外线处理的可行性。     

耀江大厦顶层屋面热泵的振动治理

本文通过耀江大厦27层屋面上六台热泵振动治理前后的振动和噪声测试数据的对比，简要阐述了安装在屋面上热泵的振动影响的程度和范围、产生振动影响和固体噪声传递的原因，并介绍了热泵双层隔振的方法和隔振效果。     

鸡东县广播电视HFC城网改造设计方案

根据有线电视的数字化、光纤化发展趋势，现在的有线电视网络必须经过改造，以便为今后数字电视的传输和双向传输打下基础，进一步拓展有线电视的功能，为此提供一个城网改造的方案供参考。     

红外多元探测器的噪声仿真研究

分析了红外多元探测器的噪声来源，建立各种噪声的公式。并以“L”型探测器为例分析其噪声的信号形式有三种：白噪声、正弦噪声、分形噪声。采用MATLAB语言对分析结果进行了仿真。     

机械臂的动态混合控制

本文研究当机械臂的终端受有约束时的控制问题,其中心内容是给出“任务规范投影算子”的概念,利用它首先将机械臂的动态方程解耦为两组方程,它们分别描述了运动与约束力,在此基础上给出了机械臂的控制律,使闭环系统跟踪期望的速度与约束力。     

自振空化射流提高钻井速度的实验研究

空化射流用于提高钻井速度的可行性研究结果表明，在钻进作业中，利用空泡破裂产生强大破坏作用来提高钻探的效率，其效果显著，可行性高。室内实验表明，自振空化射流在比普通喷嘴射流更深的井底或更高的围压条件下，有更大的起始空化数和更强的空化能力。自振空化喷嘴起始空化数大都在1.0以上，最高达到1.67，而锥形喷嘴最高仅为0.43，围压下其冲蚀效率是锥形喷嘴的1~2倍。现场试验同样证实设计的自振空化射流喷嘴在保护钻头、减少钻头磨损及增加进尺、提高机械钻速方面有显著作用。