Photochromism of a novel asymmetrical diarylethene with a (formyloxyethoxy)ethyl‐linked naphthalimide moiety

A novel asymmetrical diarylethene with a (formyloxyethoxy)ethyl‐linked naphthalimide unit was synthesized, and its photochromic and fluorescence properties were systematically investigated in both solution and a poly(metyl methacrylate) film. The diarylethene showed significant photochromism and notable fluorescence switching properties upon irradiation with ultraviolet/visible light. Compared with the parent diarylethene, introduction of the naphthalimide moiety was effective to increase the molar absorption coefficient, the fluorescence quantum yield, and fluorescent modulation efficiency of the diarylethene. Copyright © 2014 John Wiley & Sons, Ltd.     

Power dissipation characteristics of great power and super high speed semiconductor switch

The power dissipation characteristics of pulsed power switch reversely switched dynistors （RSDs） are investigated in this paper. According to the expressions of voltage on RSD, derived from the plasma bipolar drift model and the RLC circuit equations of RSD main loop, the simulation waveforms of current and voltage on RSD are acquired through iterative calculation by using the fourth order Runge-Kutta method, then the curve of transient power on RSD versus time is obtained. The result shows that the total dissipation on RSD is trivial compared with the pulse discharge energy and the commutation dissipation can be nearly ignored compared with the quasi-static dissipation. These characteristics can make the repetitive frequency of RSD increase largely. The experimental results prove the validity of simulation calculations. The influence factors on power dissipation are discussed. The power dissipation increases with the increase of the peak current and the n-base width and with the decrease of n-base doping concentration. In order to keep a low power dissipation, it is suggested that the n-base width should be smaller than 320μm when doping concentration is 1.0×10^14cm^-3 while the doping concentration should be higher than 5.8×10^13cm^-3 when n-base width is 270μm.     

基于SOS的脉冲功率源技术新进展

 研制了基于SOS的胡杨200和胡杨700脉冲功率源。给出了胡杨200和胡杨700的电路原理、组成结构和实验波形。介绍了在SOS脉冲功率源上开展的高重复频率强流电子束产生、长寿命阴极实验、绝缘介质的高重复频率击穿实验和低引导磁场无箔二极管等实验研究进展。经测试，胡杨200在2 kHz重复频率、负载阻抗200 Ω下，输出电压200 kV，脉冲宽度约35 ns，平均输出功率大于10 kW；在300 Hz条件下可连续运行。胡杨700同样为全固态脉冲功率源，其设计指标:输出电压700 kV，电流5 kA，脉冲宽度约40 ns；经初步调试在150 Ω电阻负载上单脉冲输出指标达到660 kV，4.4 kA，脉宽约70 ns。     

PPCP用固态脉冲电源的实验研究

 介绍了一种采用半导体开关与磁开关、可饱和脉冲变压器相结合技术的固态脉冲电源，此电源可用于脉冲放电等离子体烟气治理。在理论分析的基础上建立了实验模型，通过实验验证了此类电源的可行性，解决了8支晶闸管开关串联的动静态均压及开通同步性问题，并对可饱和脉冲变压器及磁开关的工作特性进行了分析计算。电源在阻性负载上得到峰值电压37.5 kV、前沿101 ns、脉宽1 μs的脉冲，重复频率300 Hz，输出功率10 kW。     

假火花开关初始放电过程的理论计算

假火花开关具有耐压高、放电电流大及电流上升速率快的优点。本文利用流体模型及当地场近似，对其放电过程进行了理论计算。结果表明，在放电初始阶段，空心阴极效应起关键作用。同时，对不同初始条件（初始电子、离子密度不同）及不同边界条件（开关结构尺寸不同）的放电过程进行了计算。给出了放电时间、放电电流、最佳阴阳极距离和阴极孔尺寸大小。     

Ge_xSi_（1－x）／Si异质结无间距定向耦合光开关模型分析

提出一种简便可行的ＧｅｘＳｉ１－ｘ异质结无间距定向耦合光开关（ＢＯＡ型－ＢｉｆｕｒｃａｔｉｏｎＯｐｔｉｃａｌＡｃｔｉｖｅ）模型分析方法。该方法采用等离子体包散效应分析了这种光开关的电学调制机理；采用异质结超注原理分析了开关的电学性质；并根据典单模脊形波导理论和上述分析，设计了利用双模干涉机制工作的Ｇｅ０．０５ＳＩ０．９５／Ｓｉ异质结ＢＯＡ型光开关的结构参数和电学参数。     

GW──I磁传感器实验仪研制

本文介绍了自制磁传感器实验仪的原理。     

Spectral anomalies and spectral switches of partially coherent and polychromatic light diffracted at an aperture

Inrecentyearsanewbranchofmodernphysicalopticscalledsingularoptics[1]hasbeendeveloped.In2002theworkinsingularopticswasextendedfrommonochromaticlighttospatiallyfullycoherentandpolychromaticlightbyGburetal.[2—4].Itwasfoundthat,whenaconverging,spatiallyfullycoherentandpolychromaticsphericalwaveisdiffractedatanaperture,anomalousspectralchangestakeplaceclosetozerosoftheintensityinthefarfield;i.e.thespectrumisredshiftedatsomepoints,blueshiftedatothers,andsplitintotwolineselsewhere.Thepredictionsofsp…     

Delayed breakdown diode and its optimal design for solid state picosecond closing switch

We study a Si-based diode with a p⁺nn⁺ structure for picosecond semiconductor closing switch and discuss the physical process, which underlies the operation principle of high-power closing switch based on a delayed breakdown diode (DBD). From the results of numerical simulations and theoretical analysis, single device has demonstrated reliable operation at 2.3 kV, 89 ps risetime, and high output dV/dt(30 kV/ns). As a contribution to the optimal design, some conclusions about trade-off are drawn by changing structure parameters and physical parameters.     

电流控阈技术及三值电流型 CMOS施密特电路

本文以开关信号理论为指导 ,对电流型 CM OS电路中如何实现阈值控制进行研究. 建立实现阈 值控制电路的电流传输开关运算 ,并用于指导电流型 CMOS施密特电路的开关级设计 .用 PSPICE程序 模拟证明了所设计的电路具有理想的施密特电路特性.