1/spl phi/ 3W grid-connection PV power inverter with partial active power filter

This paper presents a single-phase three-wire (1/spl phi/ 3W) grid-connection photovoltaic (PV) power inverter with a of partial active power filter (PAPF) feature, which can not only deal with PV power but filter current harmonics and improve power factor. Once the processed power exceeds the switch ratings, the inverter can reduce its output reactive power and harmonic power, while still supplying the maximum real power generated by the PV arrays. In the derivation of control laws, a limit circle is defined to confine the output power of the inverter. To determine the power that the inverter can process, the instantaneous reactive power of a 1/spl phi/ 3W system is defined and used to calculate reactive power, which can avoid complex detections of phase angle and magnitude of the fundamental component of a nonlinear load current. Simulation results and experimental measurements have verified the proposed algorithm and the feasibility of the inverter.     

Reconstructed 3-d magnetic field structure and hard X-ray two ribbons for 2000 Bastille-day event

The Bastille-day event in 2000 produced energetic 3B/X5.6 flare with a halo CME, which had great geo-effects consequently. This event has been studied extensively and it is considered that it follows the two-ribbon flare model. The flare/CME event was triggered by an erupting filament and TRACE observations showed formation of giant arcade structures during the flare process. Hard X-ray (HXR) two ribbons revealed for the first time in this flare event (Masuda et al., 2001). The reconstruction of 3-D coronal magnetic fields revealed a magnetic flux rope structure, for the first time, from extrapolation of observed photospheric vector magnetogram data and the flux rope structure was co-spatial with portion of the filament and a UV bright lane (Yan et al., 2001a, 2001b). Here we review some recent work related to the flux rope structure and the HXR two ribbons by comparing their locations and the flux temporal profiles during the flare process so as to understand the energy release and particle accelerations. It is proposed that the rope instability may have triggered the flare event, and reconnection may occur during this process. The drifting pulsation structure in the decimetric frequency range is considered to manifest the rope ejection, or the initial phase of the coronal mass ejection. The HXR two ribbons were distributed along the flux rope and the rope foot points coincide with HXR sources. The energy dissipation from IPS observations occurred within about 100 R _⋅ is consistent with the estimate for the flux rope system. This revised version was published online in August 2006 with corrections to the Cover Date.     

数据采集系统的总体评价

从性能指标出发，综述了数据采集系统总结评价技术的发展状况。并提出了对数据采集系统性能指标的两类分类方法 。     

侧链含硝基氮杂基团的聚醚粘合剂的性能及应用──新型硝基粘合剂研究Ⅲ

对新型的侧链含硝基氨杂基因的富能聚醚粘合剂──端羟基２─甲硝胺基乙基缩水甘油醚均聚醚（ＮＰＥ—Ａ）和端羟基共聚醚（ＮＰＥ—Ｂ）的性能进行了研究。结果表明，ＮＰＥ的热稳定性和化学稳定性良好，优于普通碳氢聚醚粘合剂（ＨＣＰＥ）和新型氟碳聚醚粘合剂（ＦＣＰＥ）；其固化后的力学性能良好。简要地叙述了以ＮＰＥ—Ｂ为粘合剂的固体火箭推进剂的配方和性能。     

基于多相正交序列移位序列的CDMA通信系统

介绍多相正交序列的构造方法,对多相正交序列的自相关和互相关特性进行分析。提出采用多相正交序 列的移位序列作为扩频序列的通信方式,并给出接收端序列同步的实现方法。这种方式能解决低相数多相正交序列互 相关特性不理想,而高相数多相正交序列难以搜索的困难。     

载人航天可靠性与空间环境试验

文章通过对国外载人航天事故统计,分析各种空间环境条件对航天器及航天员的影响,阐述了空间环境试验对提高载人航天可靠性的重要意义,提出为了提高载人航天的可靠性,应进行充分和严格的空间环境模拟试验。     

振动对空间光通信系统误码率影响的分析

在空间光通信系统中，由于卫星平台的振动，使得光发射机发生振动，从而对通信系统的误码率产生影响，本文针对光射光束为高斯光束时，振动对误码率的影响问题进行研究。结果表明，在振动时不仅振幅影响着误码率，而且波长也对误码率有影响，但通信距离对误码率的影响不大，一般可以忽略。     

Kevlar/Nomex蜂窝夹层结构表面粘贴镀铜箔聚酰亚胺薄膜的工艺研究

文章对Kevlar面板Nomex蜂窝夹层结构表面粘贴镀铜箔聚酰亚胺薄膜的工艺进行了研究,分析了工艺特点、工艺流程、工艺难点,以及针对工艺难点所采取的工艺措施,最后根据产品的研制情况给出结论。     

基于软件工程基本原理的电子商务网站建设

针对电子商务网站建设过程中存在的问题，从软件工程基本原理出发，分析结合软件生存周期瀑布模型提出电子商务网站的建设过程，对克服当前主要不足有一定的帮助作用。     

黑井古镇:消逝的古盐都

虽不见了旧时车马喧嚣的繁华，但走在那红砂石铺就的街面，还是能见到不少尚好的陈年旧物，寻觅到一些沉积的历史片段。这要得益于当地人世代坚守的“卖屋不富，置物不穷”的古训，