Electrostatic discharge effect on safe distance determination for 500 kV ac power line's helicopter inspection

The effect of electrostatic discharge on safe distance determination for 500 kV ac transmission line's helicopter inspection is investigated. Potential difference exists while helicopter is near the power transmission line, which is harmful to the inspection persons. The electric field in the helicopter cabin is calculated when it is near the power line. The result indicates that the potential difference becomes higher with the decrease of the distance between the helicopter and transmission line. Considering the discharge energy and the guarantee of the persons' safety, the safe distance for 500 kV ac transmission lines is determined as d ≥ 15 m.     

电气原理草图语义理解系统开发

在当前已有的手绘草图识别系统及算法的基础上,设计了一个简单的手绘电气元件识别系统.通过在线采集获取手绘图每个笔画的始终点坐标以及每个笔画上所有的采样点的坐标,然后通过平滑处理以及去重处理来降低因输入时候的抖动噪音之类的因素对识别的影响.实现了基于图元以及图元数量的单个电气元件的识别方法.系统使用MATLAB做为软件开发平台,通过仿真验证算法的可行性,所达到的识别效果能够实现预期的设计要求.     

Electrochemical polymerization of alizarin and the electrochemical properties of poly(alizarin)

Electrochemical polymerization of alizarin on glassy carbon electrode (GCE) was carried out in acidic solution by cyclic voltammetry (CV), and the polymerization process was monitored by electrochemical quartz crystal microbalance (EQCM). A possible mechanism concerning the polymerization of alizarin was also proposed in this work. The as-synthesized poly(alizarin) was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy (EIS). The study on electrode reaction process shows that the electrode reaction of poly(alizarin) is controlled by diffusion. Finally, the activation energy (E _a) of the electrode reactions of poly(alizarin) was obtained according to the temperature dependence of the redox peak currents.     

太赫兹互补金属氧化物半导体场效应管探测器理论模型中扩散效应研究

针对基于经典动力学理论传统模型中忽略扩散效应的问题,通过对基于玻尔兹曼理论的场效应管传输线模型的理论分析,建立了包含扩散效应的太赫兹互补金属氧化物半导体(CMOS)场效应管探测器理论模型,研究扩散效应对场效应管电导及响应度的影响.同时,将此模型与忽略了扩散效应的传统模型进行了对比仿真模拟,给出了两种模型下的电流响应度随温度及频率变化的差别.依据仿真结果,并结合3σ原则明确了场效应管传输线模型中扩散部分省略的依据和条件.研究结果表明:扩散部分引起的响应度差异大小主要由场效应管的工作温度及工作频率决定.其中工作频率起主要作用,温度变化对差异大小影响较为微弱;而对于工作频率而言,当场效应管工作频率小于1 THz时,模型中的扩散部分可以忽略不计;而当工作频率大于1 THz时,扩散部分不可省略,此时场效应管模型需同时包含漂移、散射及扩散三个物理过程.本文的研究结果为太赫兹CMOS场效应管理论模型的精确建立及模拟提供了理论支持.     

The photocatalytic mechanism of BiOI with oxygen vacancy and iodine self-doping

The photocatalytic mechanism of BiOI with an oxygen vacancy and iodine self-doping is investigated by studying their structural, electronic and optical properties. The results of the first-principle calculations indicate that the utilization of the visible light region is broadened, and thus the photocatalytic performance is improved, via introducing an oxygen vacancy or I dopant. Among them, I-Bi doped BiOI shows the best photocatalytic performance, and it is also the preferred one of the three structures due to its better stability. The occurrence of I-Bi or I-I interactions in the original double iodine layer along with the introduction of I dopant leads to a planar localization of the photocatalytic mechanism. Then it is expected that the photo-generated carriers will transfer to the catalyst surface more easily; the photocatalytic activity of BiOI relies on the planar localization to a great degree.     

PPLT倍频宽线宽掺镱双包层光纤放大激光

分别通过理论和实验研究了周期性极化的钽酸锂（PPLT）倍频宽线宽准连续掺镱双包层光纤放大激光.PPLT样品长为40 mm,极化周期为7.67 μm.基频光的中心波长为1064 nm,线宽约为6 nm.从基频光的光谱特性出发,利用超晶格倍频理论,解释了实验中获得的倍频温度与二次谐波功率之间的关系.在基频光的功率为2.2 W时,获得的宽线宽光纤激光倍频效率为1.8%.     

Tomographic analysis of the central magnetohydrodynamic oscillations on the HT-7 tokamak

Multi-channel soft x-ray (SX) detectors are applied to generate images of magnetohydrodynamic (MHD) oscillation on the HT-7 tokamak, and the data from SX cameras are analysed by using the Fourier--Bessel harmonic reconstruction method and the singular value decomposition. The image reconstruction of SX emissivity is obtained on the assumption of plasma rigid rotation. One of the important phenomena in the HT-7 discharge is the transition from the sawtooth oscillations to the MHD oscillations when the plasma density grows higher. The MHD structure observed in the SX tomography is featured as follows: the magnetic surface of MHD structure is made up of the crescent-shaped ``hot core' and the circular ``cold bubble'. The structure of the magnetic surface is relatively stable. It rotates in the direction of the electron diamagnetic drift at a frequency being the oscillation frequency of the MHD oscillations.     

H原子与CO2分子碰撞的化学反应与能量转移

用时间分辨傅立叶红外发射光谱的方法对H原子与CO2分子的碰撞动力学进行了实验研究．用紫外激光光解的方法分别制备出三个不同平动能为174．7、241．0和306．2 kJ／mol的氢原子,并引发H CO2→OH CO反应．观察到了反应的产物,即振动激发的CO (v≤2)．同时也看到了在H原子与CO2分子的碰撞中发生高效的T- V能量转移．CO2的反对称伸缩模的最高振动能级为v=4．化学反应与能量转移的速率之比大约为10．