Dynamic simulation and experimental study of inspection robot for high-voltage transmission-line

A mobile robot developed by Wuhan University for full-path hotline inspection on 220 kV transmission lines was presented. With 4 rotating joints and 2 translational ones, such robot is capable of traveling along non- obstaclestraight-line segment and surmounting straight-line segment obstacles as well as transferring between two spans automatically. Lagrange’s equations were utilized to derive dynamic equations of all the links, including items of inertia, coupling inertia, Coriolis acceleration, centripetal acceleration and gravity. And a dynamic response experiment on elemental motions of robot prototype’s travelling along non-obstacle straight-line segment and surmounting obstacles was performed on 220 kV 1∶1 simulative overhanging transmission-line in laboratory. In addition, dynamic numerical simulation was conducted in the corresponding condition. Comparison and analysis on results of experiment and numerical simulation have validated theoretical model and simulation resolution. Therefore, the dynamic model formed hereunder can be used for the study of robot control.

小鼠胸腺基质细胞株MTEC_B的细胞学特性

用免疫组织化学和透射电镜技术对本室所建立的小鼠胸腺基质细胞株ＭＴＥＣ_Ｂ进行了细胞学鉴定。免疫组织化学观察显示：４０ｋＤ、４５ｋＤ角蛋白和波形蛋白呈现强阳性，５２ｋＤ，５４ｋＤ，５８ｋＤ角蛋白和Ｓ－１００蛋白呈现阴性。电镜下见到，具有桥粒和张力丝结构，含较多的囊泡和髓样体，发达的高尔基复合体和线粒体。另外ＭＴＥＣ_Ｂ还表现为酸性磷酸酶、碱性磷酸酶、非特异性酯酶弱阳性。据此我们认为ＭＴＥＣ_Ｂ为上皮细胞来源，又因其只表达低分子量的角蛋白，而在胸腺原位上，皮质上皮细胞也只表达低分子量的角蛋白，故ＭＴＥＣ_Ｂ可能为胸腺皮质上皮细胞。

Nonlinear Wave in a Disc-Shaped Bose-Einstein Condensate

We discuss the possible nonlinear waves of atomic matter wave in a Bose-Einstein condensate. One and two of two-dimensional （2D） dark solitons in the Bose-Einstein condensed system are investigated. A rich dynamics is studied for the interactions between two solitons. The interaction profiles of two solitons are greatly different if the angle between them are different. If the angle is small enough, the maximum amplitude during the interaction between two solitons is even less than that of a single soliton. However, if the angle is large enough, the maximum amplitude of two solitons can gradually attend to the sum of two soliton amplitudes.

Adaline and FIS Techniques for Fault Identification in HV Transmission Line

This paper is to identify and classify the various types of shunt and line faults in transmission line. The faults may be an insulation failure, lightning or accidental faulty operation. In a transmission line protection important factor is identifying a fault because if any error occurs in finding fault may leads to abnormal operation of the protection system. So either a disturbance or steady state variation is called power quality variation. The proposed test system is modeled based on the neural network and fuzzy algorithm. The online symmetrical components are extracted by this above algorithm. The fuzzy is used to separate the oscillating components and average components. Here input for the fuzzy is trained by using neural network. It is based on current samples and very effective in fault classifier using rule base. This method is very much suitable for online implementation.

Cable coupling response in metal cavity under X-ray irradiation

This study investigates the coupling response of cables inside a metal cavity under X-ray irradiation using the finite-difference time-domain method,particle simulation method,and transmission-line equation to solve the electromagnetic field inside the cavity and load voltage at the cable terminal under X-ray excitation.The results show that under a strong ionizing radiation environment of 1 J/cm^(2),a strong electromagnetic environment is generated inside the cavity.The cable shielding layer terminal couples a voltage of 15.32 V,whereas the core wire terminal couples a voltage of 0.31 V.Under strong X-ray irradiation,the metal cavity not only fails to provide electromagnetic shielding,but also introduces new electromagnetic interference.This study also provides a method for reducing the number of emitted electrons by adding low-Z materials,which can effectively reduce the coupled electric field and voltage.

An improved model of Robinson equivalent circuit analytical model

The Robinson equivalent circuit analytical model can be used only in calculating shielding effectiveness of enclosure with the same multi-holes in one wall, but cannot be used in different multi-holes in two walls. According to the practical requirement, this article uses Konefal's and Farhana's characteristic impedance of apertures to improve the equivalent circuit analytical model in different multi-holes in two walls. The improved equivalent circuit analytical model is more useful than Robinson equivalent circuit analytical model. In the article, all kinds of enclosures are simulated by TLM (Transmission-Line Matrix method) to prove that this improved model is feasible in multimode.

Automatic Removal of Multiple Artifacts for Single-Channel Electroencephalography

Removing different types of artifacts from the electroencephalography(EEG)recordings is a critical step in performing EEG signal analysis and diagnosis.Most of the existing algorithms aim for removing single type of artifacts,leading to a complex system if an EEG recording contains different types of artifacts.With the advancement in wearable technologies,it is necessary to develop an energy-efficient algorithm to deal with different types of artifacts for single-channel wearable EEG devices.In this paper,an automatic EEG artifact removal algorithm is proposed that effectively reduces three types of artifacts,i.e.,ocular artifact(OA),transmission-line/harmonic-wave artifact(TA/HA),and muscle artifact(MA),from a single-channel EEG recording.The effectiveness of the proposed algorithm is verified on both simulated noisy EEG signals and real EEG from CHB-MIT dataset.The experimental results show that the proposed algorithm effectively suppresses OA,MA and TA/HA from a single-channel EEG recording as well as physical movement artifact.

Influence of facet reflection of SOA on SOA-integrated SGDBR laser

A combined model of the transmission-line laser model （TLLM） and the digital filter approach is developed to simulate the shuttering characteristic of a semiconductor optical amplifier （SOA）, which is inte- grated with a sampled grating distributed Bragg reflector （SGDBR） laser, to create a so called SOA-SGDBR laser. The SOA section acts as a shutter to blank the laser output during wavelength switching events. Simulated results show that the turn-on edge of the SOA blanking process will oscillate when the facet reflection of SOA is relatively high. This phenomenon is also observed by experiments.

Influence of Qinghai-Tibet HVDC Transmission System on AC Transmission Line Protections in Qinghai Power System

To analyze the influence of _＋400 kV Q^nghai-Tibet HVDC transmission system on transmission- line protections in Qjnghai AG power system, a closed-loop simulation system was constructed by combing HyperSim system with HVDG control protection devices. Various faults on double-circuit 750 kV and multi- circuit 330 kV AC transmission lines in Qjnghai power system were simulated. The impedance characteristics and harmonic components at Qjnghai side of Qjng-Tibet DG transmission line were analyzed. The harmonic proportion in voltages and currents were studied for faults that took place at different locations near the DG system. The inflence of Qing-Tibet DG system on the directional components of protections, differential protections and distance protections of AC transmission lines was discussed and drew the conclusions that the DC sytem had little influence on differential protections, while had great inflence on directional components and distance protection. The conclusions can provide reference for studying the interaction between AC and DG systems.