通信线路中电力谐波干扰与防护分析

谐波干扰的危害是在通信线路中感应谐波噪声而使通信质量下降,或使重要的控制和保护设备发生误动作以及使电力装置过载,谐波的存在常常在事故发生后才能检测出来,对于常规的电器用户,由于它们自身的控制设备与供电系统的谐波相互作用而使运行困难不断增加.本文从谐波的产生、耦合方式和防护方法进行了分析,探讨了通信线路消除干扰和进行防护的基本措施.     

Formation of combined solitons in two-component Bose—Einstein condensates

<正>We investigate the combined soliton solutions of two-component Bose—Einstein condensates with external potential. The "phase diagram" is obtained for the formation regions of different combined solitons.Our results show that the intraspecies(interspecies) interaction strengths and the external trapped potential clearly affect the formation of dark-dark, bright-bright,and dark-bright soliton solutions in different regions.Especially,we find that the bright-bright (dark-dark) soliton can exist in the case of both repulsive(attractive) intraspecies interaction strengths in the presence of external potential.This novel phenomenon is completely different from the formation of soliton solution of one-component Bose-Einstein condensates without external potential,and it will be useful for the study of two-component Bose-Einstein condensates.     

谈《大学物理网络教学系统》的可扩充性

大学物理网络教学系统充分利用多媒体资源，教学素材形式多样，将不同性质的信息媒体集中为一个整体，实现了基于WWW进行交互处理的过程，使信息理解更加方便，及时，容易，增加了信息利用的时效性，整个系统具有良好的积件功能和内容的可扩充性，可以方便地增加新的软件模块和扩展多种教学信息，因而为系统的不断完善提供了广阔空间。     

数列中对一切正整数恒成立问题的研讨

文[1]对2004年高考江苏卷第20题的探索是很有意义的，令人耳目一新，笔者通过挖掘隐含在问题内部的研究性材料进行推广，既能让学生真正掌握所涉及的内容，又利于其探究能力的培养。     

从动力学驰豫的测量结果推导临界电流密度Jc0（T,Be）的直接方法

本给出了一种从高温超导体动力学驰豫的测量结果推导其临界电流密度Ｊｃ０（Ｔ，Ｂｅ）的直接方法。这种方法与ＧＩＳ相比，避免了ＧＩＳ中所涉及的复杂的讨论和处理，使问题变得直接和明朗。同时，用这种方法还可以从动力学驰豫的测量中求出μ和Ｕｃ随温度和磁场的依赖关系μ（Ｔ，Ｂｅ）、Ｕｃ（Ｔ，Ｂｅ）。     

A Spin Glass Model with Vibrations of Crystal Lattices

With the help of the replica method and imaginary-time functional-integrate technique, the spin glass model with the vibrations of crystal lattices is investigated. In the limit of the replica symmetry and the imaginary-time static approximation, the magnetic and thermodynamic quantities have been obtained. By the numerical calculations, we found that the magnetization of the system has the typical spin-glass behaviour. A peak is found in the susceptibility-temperature curve and is shifted to lower temperature with increasing applied field. Due to the lattice contribution, the specific heat increases strongly at high temperature.“ Due to the magnetic contribution, the anomaly in the specific heat-temperature curve forms a λ-type peak, which agrees with the observation of Rojo et al. [Phys. Rev. B 66 (2002) 094406].     

高温超导磁阻电机的研究

本文针对超导磁阻电机结构并结合临界态模型，利用有限元法计算电机内部磁场和交直轴电抗，借以分析电机稳态工作特性，通过样机构造及其性能测试和分析，证实了HTS磁阻电机较传统电机能够以更小体积和重量实现更大的输出功率、更高的功率因数和效率，此项研究为百kW-MW级HTS磁阻发电／电动机研发奠定了良好的理论和实践基础．