金属纳米柱天线的快速电磁分析

基于分段正弦基函数和矩量法,通过求解离散电流节点格林函数的封闭解得到金属纳米柱天线激发表面等离子体的阻抗矩阵.与使用其它基函数矩量法相比,该方法可以减少矩阵方程的维数.仿真结果表明:使用此方法只需求解很小的矩阵方程就可以求解出纳米天线表面极化电流,从而实现对纳米天线的散射特征及谐振模式的快速分析;其结果与时域有限差分仿真结果吻合良好且速度具有显著的优势,尤其在计算斜入射问题时计算优势更加明显.本文的方法对文中计算的模型有效,同样为其他形状纳米柱天线和碳纳米管器件散射特性仿真提供了快速有效的电磁分析方法.     

模拟触电演示仪

设计了模拟触电演示仪,在低压直流电条件下,通过操作布偶来生动模拟人体触电的各种情形.学生可从视觉、听觉和触觉多角度真切地体会到触电的反应,达到教育学生安全用电的教学效果.     

基于Zigbee与GPRS网络数据传输技术的黄河河道断面冰水情多点自动监测系统设计与应用

基于空气、冰与水物理特性差异的冰情检测方法是一种可以实现对检测点垂直柱面冰层内部物理状态连续在线检测的新型冰情检测方法.方法由于受测试点的局限,仅仅实现了对河道断面的单点取样数据采集,无法掌握河道断面整体冰生消变化的过程,在工程应用中受到限制.结合黄河冬季冰情现场实验的需求,在原有基于空气、冰与水物理特性差异的冰情检测系统基础上,融合了Zigbee和GPRS网络数据传输技术设计了一套黄河河道断面冰水情多点自动监测试验系统.现场试验结果表明,系统实现了对河道断面多点数据的连续实时采集和传输,可以满足工程中对河道断面多点实时监测的需求.     

Measurement of trace explosive residues in a surrogate operational environment: implications for tactical use of chemical sensing in C-IED operations

A campaign to measure the amount of trace explosive residues in an operational military environment was conducted on May 27–31, 2007, at the National Training Center at Fort Irwin, CA, USA. The objectives of this campaign were to develop the methods needed to collect and analyze samples from tactical military settings, to use the data obtained to determine what the trace explosive signatures suggest about the potential capabilities of chemical-based means to detect IEDs, and, finally, to present a framework whereby a sound understanding of the signature science can be used to guide development of new sensing technologies and sensor concepts of operation. Through our use of combined background and threat signature data, we have performed statistical analyses to estimate upper limits of notional sensor performance that is limited only by the spatial correlation of the signature chemicals to the threats of interest.     

The modified method of characteristics with mixed finite element domain decomposition procedures for the transient behavior of a semiconductor device

For the transient behavior of a semiconductor device, the modified method of characteristics with mixed finite element domain decomposition procedures applicable to parallel arithmetic is put forward. The electric potential equation is described by the mixed finite element method, and the electric, hole concentration and heat conduction equations are treated by the modified method of characteristics finite element domain decomposition methods. Some techniques, such as calculus of variations, domain decomposition, characteristic method, energy method, negative norm estimate and prior estimates and techniques are employed. Optimal order estimates in L² norm are derived for the error in the approximation solution. Thus the well‐known theoretical problem has been thoroughly and completely solved.© 2010 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 28: 353–368 2012     

DC Townsend Discharge in Nitrogen: Temperature‐Dependent Phenomena

Low‐current Townsend discharge in nitrogen has been studied in the temperature range of T = 100–300 K in a semiconductor‐gas‐discharge structure. It was found that the sustaining voltage U_S increases with time when a current is passed through the structure at low T. This effect was not observed at room temperature. A hypothesis is put forward that a film of a neutral phase of nitrogen is formed on the electrodes under cryogenic discharge conditions. The presence of the condensed thin‐film phase leads to a decrease in the secondary electron emission from the electrode and to a corresponding increase in U_S. A possible mechanism of the phenomenon is associated with the formation of large neutral aggregates in the form of [N⁺₂(N₂)_n]^– in the gas discharge volume. The condensation of these aggregates seems to yield a phase that is comparatively stable at cryogenic temperatures (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

基于纳米孔阵列增透膜的光伏器件特性分析及实验研究

利用严格耦合波理论分析了纳米孔阵列薄膜的光学特性,提出将纳米孔阵列薄膜作为光伏器件 增透膜来提高器件的光吸收和转换效率.理论分析表明:纳米孔阵列薄膜比单层增透膜有更好的增透效果, 能够更好地提高光伏器件的转换效率,在400 nm-600 nm波段尤为显著.纳米孔阵列薄膜的最优结构参数: 周期为500 nm,填充率为0.2,厚度为110 nm.采用微纳加工技术,在Φ 200 μm Si 探测器的增透膜上制作了不同周期的纳米孔阵列,并搭建了相应的测试系统.实验结果表明: 周期为500 nm时器件的性能提高最为明显,短路电流在400 nm-1100 nm波段提高约为6%, 在400 nm-600 nm波段提高约为15%;开路电压提高约为2%.纳米孔阵列薄膜能够很好地提高光伏器件 的转换效率.     

真空和常规封装下有机发光器件寿命试验

对紫外固化环氧树脂封装的商品蓝光有机发光器件进行了打开封装后在高真空（10-5 Pa）环境下的寿命实验,同时对未开封的同样器件在大气环境下进行了同样参数的寿命实验。实验结果表明,高真空下未封装器件的加速寿命为1675 h,而大气下封装器件的加速寿命为1224 h。这一结果表明在高真空环境下,有机发光器件的寿命有明显的提高,这证明了水蒸气和氧气通过紫外固化环氧树脂封装材料的渗透是影响紫外环氧树脂封装有机电致的发光器体(OLED)寿命的重要因素;封装器件内的吸气片不能完全吸收经封装渗透进入器件内的水蒸气和氧气。除了水蒸气和氧气渗透封装的因素外,OLED的寿命过程还存在其他的重要影响因素。     

重复频率脉冲功率系统触发器设计

根据重复频率脉冲功率系统中大功率开关器件氢闸流管的触发原理,针对选用的氢闸流管VE4147的触发要求,设计了直流偏压-150 V、空载电压2 000 V、脉冲电流10 A、脉冲宽度800 ns、重复频率10 kHz的触发器。设计中着重从增强抗干扰能力、降低功耗、改善散热等方面进行考虑,保证触发器以10 kHz的重复频率持续工作,已经应用于100 kV/2 kHz高压脉冲电源、70 kV/10 kHz氢闸流管老练平台、150 kV/1 kHz可调脉宽电晕等离子体驱动源等多个重复频率脉冲功率系统中。     

古代计时器——水钟

通过对中国古代计时器水钟的原理研究,利用现代的技术和材料制作了水钟.采用2种方式将匀速的水流转化为其他形式变量:一种是水滴计数法,水钟计时时长15min,累计误差6s;另一种是将匀速的水流转换成质量信号,计时时长10min,累计误差2～3s.