Investigation of N–S asymmetry of solar differential rotation by various patterns for solar cycles 20 and 21

For solar cycles 20 and 21 the latitudinal variations of the solar rotation rates are found using data of the H_α filaments and the long-lived magnetic features of negative and positive polarities. Analysis of the data showed that: (a) there is N–S asymmetry in the equatorial rotation of the H_α filaments and the long-lived magnetic features; (b) for both solar cycles the long-lived magnetic features of both polarities have similar behavior; (c) in the solar cycle 20 the long-lived magnetic features of both polarities vary in phase to each other but show some difference during cycle 21. For the long-lived magnetic features of positive polarity the confidence level is lower than for those of negative one.     

单线圈小功率SPT设计及实验

为了研究小功率SPT（稳态等离子推力器）内部的磁场分布和性能特性,应用参数化方法研制了单线圈小功率SPT。利用简化模型计算了磁场分布,并与实验进行对比,对其整体性能特性进行了实验研究。磁场测量结果和计算结果基本吻合,说明简化计算模型的可行性;实验中SPT能够顺利点火,性能测试结果达到了设计要求,结果表明,SPT可稳定工作在100～450W;当出口最大磁感应强度为300Gs,梯度为300Gs/cm时,SPT效率较高。     

复杂电磁环境下RS422接口保护电路的实现

在复杂电磁环境下如果对422通信接口进行带电热插拔操作会引发高电压冲击,当热插拔瞬间放电电流大于串口芯片所能承受的最大电流时,串口通信接口电路会被烧毁,为了有效保护通信接口电路,介绍了一种的串口热插拔保护电路,它的原理是使用对地二极管将瞬态的高电压抑制下来,在不改动设备的前提下可以对422通信接口电路提供有效的保护。经实践证明对RS422接口电路有明显的保护作用,也可以应用于其他串行通信电路。     

一种基于集成电路的旋翼转速调节器研制

在对直升机旋翼转速调节系统分析研究的基础上,提出了一种基于集成电路设计旋翼转速调节器的总体设计方案,完成了具体电路设计,采用Multisim仿真工具验证了模块电路设计的正确性.实际应用表明,旋翼转速调节器功能完备,各项性能指标满足直升机所提出的性能指标要求,可在直升机上推广使用.     

Multi-point observations of earthward fast flow in the plasma sheet by virtual satellites located in the MHD simulation domain

Time profiles of some physical values in earthward fast flows in the plasma sheet are observed at three dimensionally different positions by employing virtual satellites located in the three-dimensional magnetohydrodynamic simulation domain, and these simulations are done on the basis of the spontaneous fast reconnection model. In the spontaneous fast reconnection evolution, the width of the flow channel is narrow in the dawn-dusk direction, and it does not spread until the plasma collides with the magnetic loop. The enhancements in B_z and V_x are larger at the center of the fast flow channel than those at its dawn and dusk edges, reflecting the differences in the reconnection rate in the diffusion region. The enhancement in V_x is shorter near the plasma sheet boundary layer than that near the neutral sheet, reflecting the changes in the thickness of the flow channel.     

基于矢量网络分析仪的相对介电常数扫频测量

采用波导短路法对介质材料的相对介电常数进行扫频自动测量,通过VC＋＋开发了一套宽频带（8GHz~18GHz）复介电常数自动测量系统。用矢量网络分析仪对波导采样器进行扫频测量,不仅可以得到被测材料介电常数的频率特性,而且能够解决超越方程多值解的判断问题,并减少了测量中的误差。通过对介质样品的实际测量,可以发现,该自动测量系统操作简单、测量速度快,测量结果能够达到较高准确度,结果令人满意。     

离子推力器小功率正高压屏栅电源研究

为了设计一种适用于小功率离子推力器的小功率正高压屏栅电源,本文提出了一种前级降压斩波电路后级全桥LLC谐振及全波倍压整流的两级式拓扑结构。在该主电路的基础上,设计了控制电路,并开展了试验研究。试验结果表明：设计的正高压屏栅电源在输入电压42 V、输出负载12.52 kΩ时,输出电压和输出功率分别为1050 V、88 W,且输出电压误差范围控制在2%以内,屏栅电源效率为90.44%。对于输出正负极高压短路、瞬时加减载具有自恢复功能。研究证明了该两级式拓扑结构的可行性,从而提供了一种小功率正高压屏栅电源的设计方法,对小功率离子推力器的发展具有推动作用。     

一种行波型超声电机驱动器的研制

针对超声电机的工作原理和驱动要求,研制一套适用于行波型超声波电机的驱动器。对比分析驱动器与普通驱动电源对超声电机性能的影响,实验结果表明,驱动器的输出波形与参数均满足设计要求,超声电机的输出性能也基本一致。在超声电机长时间运行过程中,电机与驱动器的输出性能均稳定。     

大型整星无磁转台研制方案探讨

文章介绍了气浮、静压、水压、大滚子轴承式、滚轮式等5种转台方案,同时阐述了在设备研制中,优化设计、技术更新的重要性。     

Interplanetary Physics Research in China During 2004 - 2005

This brief report summarized the latest advances of the interplanetary physics research in China during the period of 2004-2005, made independently by Chinese space physicists and through international collaboration. The report covers all aspects of the interplanetary physics, including theoretical studies, numerical simulation and data analysis.