高精度光电数据采集系统的实验研究

针对光电弱信号检测,采用Σ-ΔAD转换器AD7706和AVR单片机ATmega8515设计了适用于低频量测量的高精度数据采集器,采用Σ-ΔAD转换器ADC16471、AVR单片机ATmega8515、C51单片机C8051F020和以太网控制器RTL8019AS设计了适用于高精度线阵CCD的数据采集器,并分别对两套数据采集器进行了实验研究与性能分析。     

In silico enhancement of azo dye adsorption affinity for cellulose fibre through mechanistic interpretation under guidance of QSPR models using Monte Carlo method with index of ideality correlation

ABSTRACT

Azo dyes are a group of chemical moieties joined by azo (-N=N-) group with potential usefulness in different industrial applications. But these dyes are not devoid of hazardous consequence because of poor affinity for the fibre and discharge into the water stream. The chemical aspects of 72 azo dyes towards cellulose fibre in terms of their affinity by QSPR have been explored in the present work. We have employed two approaches, namely balance of correlation without IIC (TF₁) and balance of correlation with IIC (TF₂), to generate 16 QSAR models from 8 splits. The determination coefficient of calibration and validation set was found higher when the QSPR models were developed using the index of ideality correlation (IIC) parameter (TF₂). The model developed with TF₂ for split 3 was considered as a prominent model because the determination coefficient of the validation set was maximum (r ² = 0.9468). The applicability domain (AD) was also analysed based on ‘statistical defect’, d(A) for a SMILES attribute. The mechanistic interpretation was done by identifying the SMILES attributes responsible for the promoter of endpoint increase and promoter of endpoint decrease. These SMILES attributes were applied to design 15 new dyes with higher affinity for cellulose fibre.     

脉冲电压微分反馈法控制buck功率变换器中的混沌

通过3种典型的开关逻辑图分析了降压buck变换器中混沌产生的机理，指出开关S导通时，电 容充电过快是电路系统中混沌产生的主要原因.在此基础上提出了利用输出电压的脉冲微分 反馈对这类电路系统中的混沌进行控制的方法.理论分析、数值计算和电路仿真证实了该方 法的正确性和有效性. 关键词： 混沌 混沌控制 脉冲电压微分反馈 buck变换器     

A CW CO2 laser using a high-voltage Dc–dc converter with resonant inverter and Cockroft–Walton multiplier

I propose a high-voltage Dc–dc converter for a CW (continuous wave) CO₂ laser system using a current resonant half-bridge inverter and a Cockcroft–Walton circuit. This high-voltage power supply includes a two-stage voltage multiplier driven by a regulated half-bridge series resonant inverter. The inverter drives a step-up transformer and the secondary transformer is applied to the voltage multiplier. It is highly efficient because of the reduced amount of switching losses by virtue of the current resonant half-bridge inverter, and also due to the small size, low parasitic capacitance in the transformer stage owing to the low number of winding turns of the step-up secondary transformer combined with the Cockroft–Walton circuit. I obtained a maximum laser output power of 44 W, a maximum system efficiency of over 16%, and the stability of laser output power of about 4.6% in this laser system.     

量子密钥分发实验中的符合测量方法

采用符合测量方法提高全光纤量子密钥分发系统的数据采集速度，寻求更高的密钥生成率。主要论述了光路中的改进和符合测量的步骤、方法以及在密钥分发实验中的应用。     

一种变象管分幅/扫描的高时间分辨光谱测量方法

本文详细介绍了西安光机所正在研制中的一种变象管瞬时光谱测量系统,它由WDG30型光栅光谱头与JTG 305型变象管分幅/扫描摄影机组成。文中给出了系统的总体设计考虑、变象管及其控制和主要性能参数。     

一种新型同轴TEM-圆波导TE11模式变换器

 提出了一种新型同轴插板式模式变换器，可以实现同轴TEM到圆波导TE₁₁模式的变换。介绍了这种模式变换器的工作原理：即通过在同轴波导中沿轴向插入金属板，将同轴TEM模变换成扇形截面波导TE₁₁模，进而利用不同扇形截面波导中的相移改变电场分布的轴对称性，在同轴波导中形成同轴TE₁₁模，最后将同轴TE₁₁模转换为圆波导TE₁₁模式。基于这一原理设计了一个中心频率为3.8GHz的同轴TEM-圆波导TE₁₁模式变换器，并进行了数值模拟。模拟结果表明：这种模式变换器可以承受高功率，中心频率上转换效率为98.5%，转换效率大于90%的带宽超过10%，在3.5~4.1GHz的频率范围内反射损耗低于0.3dB。     

Novel automatic control for the optimum optical gain and phase differences in SOA-MZI wavelength converter: Theory and experiment

We have proposed, simulated, and experimentally verified the novel automatic control method and apparatus to automatically adjust and constantly maintain the optimum optical gain and phase differences in order to achieve the automatically optimized semiconductor optical amplifier (SOA)-Mach-Zehnder interferometer (MZI) wavelength converter (WC) with wide input power dynamic range (IPDR) and maximum extinction ratio (ER). Our automatic control algorithm is proposed through the results of simulation and its validity is confirmed through the experiment.     

高压功率晶体管在扫描相机中的应用

本文讨论了使用高压功率晶体管作为开关器件研制的扫描电路,并在变象管扫描相机中应用,获得了良好的结果,大大提高了扫描电路的耐大电流冲击性,提高了相机的可靠性与稳定性,最高扫速可达10mm/ns,扫描非线性最大为3%,触发晃动为±30ps.工作频率高达20kHz.     

Performance analysis for an all-optical wavelength converter using four-wave mixing (FWM) in a single mode fiber

An analytical approach is presented to determine the performance of a tunable wavelength converter based on four wave mixing (FWM) in a single mode fiber (SMF) with two pump lasers. The analysis is carried out for an intensity modulated (IM) signal taking into considerations the effects of spectral broadening due to FWM and laser phase noise. The results evaluated at a bit rate of 10 Gb/s show that the signal power is substantially higher at lower values of wavelength separation. For example, for input powers of 10 mW each, wavelength separation of 4 nm between the pump-2 and the input signal, the output converted power is found to be –10 dBm corresponding to wavelength separation of 2 nm between pump-1 and converter signal. The corresponding crosstalk power is found to be –25 dBm at a channel separation of 3 times bit rate.