高压氮气亚纳秒开关放电特性实验研究

 利用幅值约220 kV、脉宽约4 ns的高压纳秒脉冲源，对高压氮气亚纳秒气体开关放电特性进行了实验研究。实验结果表明：当气压在3~10 MPa间变化，间隔距离在0.6~1.2 mm间变化时，氮气间隙击穿电压随气压和间隙距离的增大而增大，并随气压的增大略呈饱和趋势,最高击穿电场约为2 MV/cm。开关输出电压波形的上升时间变化范围为145~190 ps，该上升时间随气压、击穿电场以及间隙距离增大而减小。     

远红外激光磁共振光谱技术及对含碳自由基分子的观测

本文报道国内建成的远红外激光磁共振 (FIRLMR)光谱仪的技术特点和工作原理。该谱仪采用CO2 激光横向泵浦远红外激光 ,样品吸收池置于远红外激光谐振腔内 ,由聚丙烯薄膜与远红外激光增益池隔开以获得很高的灵敏度 ,从而对寿命很短的自由基分子进行研究。利用该光谱仪在远红外波段测量得到了多个瞬态自由基分子CCH ,CF和CH2 的光谱 ,这些自由基分子由微波放电产生的氟原子与甲烷CH4 反应生成。     

电力安全与超导磁储能系统

随着我国大规模电力系统的逐步形成,电网的安全稳定问题日渐突出,保证电力系统的安全稳定运行已经成为电网发展和运行的重要任务.超导磁储能系统以其对系统功率需求的快速响应特性可以为提高电力系统的稳定性提供新的技术途径,同时对改善电能质量、提高可靠性也有很好的技术优势.本文在简要论证电力安全的重要性的基础上,对SMES提高系统的安全稳定性的优越性进行了分析,并介绍了国家863计划项目"高温超导磁储能系统"的工作进展.     

BALLOONING INSTABILITY IN HIGH β TOKAMAK

In this paper we show that Δ′_B is negative over parts of the second region, and that plasmas are stable to Δ′_B-driven resistive modes for realistic equilibria in which characteristics of finite-β configurations are retained. We have found that ideal instability is very sensitive to the ratio T=rΔ″/Δ′ in the second region. In comparison with previous works. results obtained by present authors show that the shift gradient Δ′ has a significant stabilizing effect on the second stable boundary, and this effect increases as the shear s becomes larger.     

1,8-二羟基-3-甲基-苯并［d,e］蒽酮的2D NMR研究

从中药芦荟(Aloe vera)中分离得到一个蒽酮类新化合物. 通过UV、IR、HREI-M S、¹H NMR和¹³C NMR及2D NMR(¹H-¹H COSY、HMBC、HMQC和J -resolved)方法， 鉴定其结构为：1,8- 二羟基-3-甲基-苯并［d,e］蒽酮. 文章的侧重点在于讨论该化合物的¹H和¹³C NMR信号的全归属.     

Weierstrass不等式的新推广

利用控制不等式理论将 Weierstrass不等式 ∏ni=1( 1± xi) >1± ∑ni=1xi推广到一般初等对称函数上 ,并且给出一个上界估计 .     

FTIR－PAS技术在卟啉类化合物中的应用（Ⅳ）──稀土乙酰丙酮－meso－四－（α－萘基）四苯并卟啉配合物的红外光谱

研究了ｍｅｓｏ－四－（α－萘基）四苯并卟啉及其Ｄｙ，Ｈｏ，Ｅｒ，ＴＭ，Ｙｂ，Ｌｕ乙酸丙酮形成的配合物在３６００～２２０ｃｍ－１范围内的傅里叶变换红外光声光谱（ＦＴＩＲ－ＰＡＳ），对主要谱带进行了经验归属。结果表明，四－（ａ－萘基）四苯并卟啉与稀土乙酰丙酮配合物中稀土金属离子配位削弱了乙酰丙酮环上Ｍ—Ｏ键的伸缩振动，使此谱带向低波数位移。金属敏感港带出现在～１５１３，～１３２３～１０９０，１０５３和～２５０ｃｍ－１。     

基于模糊PID算法的烘箱控制仿真分析

模糊算法能解决传统方法难以解决模型的不确定性、非线性、复杂等问题的任务，PID算法在定模型下控制稳态性能好，能消除静差等特点．结合这2种方法，提出模糊PID算法，应用于通用烘箱的温度控制，通过仿真分析，表明：对不同烘箱、不同环境下，用该算法控制，有高精度、超调量小，无需调节PID参数，具有智能控制等功能．     

EFFECT OF THERMAL TREATMENTS ON THE SUPERCONDUCTIVITY OF UNDOPED AND WO3 DOPED Y-Ba-Cu-O SYSTEM

Undoped and WO₃-doped Y-Ba-Cu-O ceramics have been slowly cooled in flowing oxygen or quenched in air from 900℃ to room temperature, after sintering at 900℃ for 3Oh in flowing oxygen. The ac susceptibility measurements show that the T_c of the quenched WO₃-doped Y-Ba-Gu-O superconductor can reach 88K, while the undoped Y-Ba-Cu-O ceramic quenched in air is a non-superconductor. X-ray diffraction data show that WO₃ does not enter into the YBa₂Cu₃O_7-x lattice but forms all impurity phase. The WO₃-doped YBCO specimens quenched in air consist of orthorhombic YBa₂Cu₃O_7-x phase and an impurity phase which increases with increasing WO₃ content. Raman spectra chow that oxygen contents are different for undoped and WO₃-doped samples. It la suggested that suitable doping with WO₃ can change the oxygen content and reduce the effect of thermal treatments on the superconductivity of Y-Ba-Cu-O system.     

关于Erceg伪度量与点式伪度量的一点注记

In [6],it is proved that Erceg's pseudo-metric and pointwise pseudo-metric presented by Shi are equivalent.In this paper,it is proved that Theorem 1 in[6] is wrong.Further it is proved that Erceg's pseudo-metric and pointwise pseudo-metric are not equivalent in the sense of topology.