mlsa-iai-msu-lab/ru_sci_bench_zho_cite_reranking huggingface dataset:
Study of Polluted Insulator Flashover Forecasting Based on Nonlinear Time Series Analysis

To solve the problem of the flashover forecasting of contaminated or polluted insulator,a flashover forecasting model of contaminated insulators based on nonlinear time series analysis is proposed in the paper.The ESDD is the key of flashover on polluted insulator.The ESDD value of insulator can be forecasted by the method of nonlinear time series analysis of the ESDD time series and a forecasting model of polluted insulator flashover is proposed in the paper.The forecasting model consists of two artificial neural networks that reflect relationship of environment,ESDD and flashover probability.The first is used to estimate the ESDD time series of insulator and the second is employed to calculate the probability of the flashover.A series of artificial pollution tests show that the results of the forecasting model is acceptable.
Rough Set Theory Based Approach for Fault Diagnosis Rule Extraction of Distribution System

As the first step of service restoration of distribution system,rapid fault diagnosis is a significant task for reducing power outage time,decreasing outage loss,and subsequently improving service reliability and safety.This paper analyzes a fault diagnosis approach by using rough set theory in which how to reduce decision table of data set is a main calculation intensive task.Aiming at this reduction problem,a heuristic reduction algorithm based on attribution length and frequency is proposed.At the same time,the corresponding value reduction method is proposed in order to fulfill the reduction and diagnosis rules extraction.Meanwhile,a Euclid matching method is introduced to solve confliction problems among the extracted rules when some information is lacking.Principal of the whole algorithm is clear and diagnostic rules distilled from the reduction are concise.Moreover,it needs less calculation towards specific discernibility matrix,and thus avoids the corresponding NP hard problemThe whole process is realized by MATLAB programming.A simulation example shows that the method has a fast calculation speed,and the extracted rules can reflect the characteristic of fault with a concise form.The rule database,formed by different reduction of decision table,can diagnose single fault and multi-faults efficiently,and give satisfied results even when the existed information is incomplete.The proposed method has good error-tolerate capability and the potential for on-line fault diagnosis.
Study on Power Transformers Fault Diagnosis Based on Wavelet Neural Network and D-S Evidence Theory

Transformer faults are quite complicated phenomena and can occur due to a variety of reasons.There have been several methods for transformer fault synthetic diagnosis,but each of them has its own limitations in real fault diagnosis applications.In order to overcome those shortcomings in the existing methods,a new transformer fault diagnosis method based on a wavelet neural network optimized by adaptive genetic algorithm(AGA)and an improved D-S evidence theory fusion technique is proposed in this paper.The proposed method combines the oil chromatogram data and the off-line electrical test data of transformers to carry out fault diagnosis.Based on the fusion mechanism of D-S evidence theory,the comprehensive reliability of evidence is constructed by considering the evidence importance,the outputs of the neural network and the expert experience.The new method increases the objectivity of the basic probability assignment(BPA)and reduces the basic probability assigned for uncertain and unimportant information.The case study results of using the proposed method show that it has a good performance of fault diagnosis for transformers.
Study on Edge Extraction Methods for Image-based Icing On-line Monitoring on Overhead Transmission Lines

A new method of measuring the icing thickness of transmission lines on-line is proposed in this paper.In this method,the pictures of transmission lines which are photoed by the camera on the iron tower are processed immediately to extract the edges of the transmission line conductor and transmission line insulators.The icing thickness can be gained by comparing the edges of the iced transmission line and the uniced one.Two icing image edge extraction methods are described in detail,that is,a method based on the combination of the wavelet transform and the floating threshold method and a method based on the combination of the optimal threshold method and the mathematical morphology transform.The icing images from the artificial climatic chamber and transmission lines are used to test the methods above.The results show that the method based on the wavelet transform and the floating threshold method does well in the extraction of relatively smooth edges,such as glaze icing on conductor and icing on the insulator;meanwhile,the method based on the optimal threshold method and the mathematical morphology transform does well in the edge extraction of icing on the conductor,especially the opaque rime icing on the conductor with complicated edges.
Ion Flow Field Calculation of Multi-circuit DC Transmission Lines

An upwind finite element(FE)based algorithm to calculate the ion flow field in the vicinity of multi-circuit DC transmission lines is described.The initial value estimation and boundary condition are optimized,so details of the transmission lines such as bundle conductors and ground wires can be taken into account in the simulation model.Comparison between measured and computed ground level total electrical field and ion current density shows satisfactory agreement.The ion flow field of a ±500 kV HVDC project with bipolar lines on the same tower is simulated.The total electrical field and ion current density on ground level are compared among different line arrangements.
Separating Overlapped Peaks of SF6 Decomposed Products Based on Iterative Curve-fitting Method

The SF6 decomposed products are very alike,so the peaks of the SF6 decomposed products are overlapped.It make us hard to quantitatively calculate.This paper introduced a method to separate the overlapped chromatogram peaks with iterative curve-fitting and Gauss function,and deduced the formula of the iterative curve-fitting;provided a method to calculate the initial value of the peaks intensity and width by iterative formula,and confirm the final peaks intensity and width to separate the overlapped signals.By the analysis of the real chromatogram data,it proved the validity of this method on the main components used in distinguishing the GIS internal defects.This method overcomes the influence of SF6 peak to the other thin concentration peaks,so it can be used in the study of the quantitative analysis of the decomposed products on different failures and different voltages.
Effect of Two Phase Mixtures on the Selection of the Discharge Path

This paper investigates the development,the breakdown process,and the discharge path selection of the lightning discharges in two-phase mixtures(TPMs).13 kinds of solid-gas mixtures and 3 kinds of liquid-gas mixtures are employed to study effect of two phase mixtures on the selection of the discharge path under lightning impulses.Grain size effects are shown upon these experimental results.When the diameter of solid or liquid grains is less than about 10 μm,the discharge path does not select TPM but air.And the discharge path selects TPM when the diameter is greater than about 100 μm.And when the diameter is between about 10 μm and 100 μm,the discharge path selects TPM under negative lightning impulses,but it has a greater selection of air than TPMs under positive lightning impulses.Volume fraction and permittivity of solid/liquid can also influence the selection of the discharge path.
Combination Operation for Neutral Point of 35 kV Power Grids in Mountainous Area

Based on a lot of measurement and analysis,this paper find that the unbalanced nature of 35 kV grids due to unsymmetrical capacitance values gives difficulty in neutral point operation in mountainous area.Improving compensation of Petersen coil can rectify imbalance of voltage but bring up new problem that Petersen coil can not extinguish grounding arc effectively in fault.To put down contradiction mentioned above,this paper proposes a combination operation for neutral point of 35 kV grids as neutral point insulated in routine operation and grounding through Petersen coil in fault,then EMTP simulation is carried out.Simulation indicates that new neutral operation method can improve lightning withstand level and decrease trip-out rate of grids.
Experimental Analysis on Shielding Effect of the Grounding Electrodes Under Impulse-current

Generally,the flow of a lightning impulse current from a grounding electrode into ground is a very complicated process determined by many factors.In order to analyze the mechanism of the impulse current dissipating in the earth from grounding electrode,the experiments that had been carried out by other authors almost used a single horizontal grounding wire or vertical grounding rod for sake of simplicity.However,in practical conditions,most of the grounding systems are constructed of grounding electrodes with branches in different directions.In this study,basing on the principle of dimensional similarity,impulse simulation experiments are performed on the common ground electrodes with conductor branches.This paper focuses on analyzing the impulse current dispersal regularity of different branches when injecting at one point.Comparing with the leakage current distribution of a single ground electrode,it is found that the leakage currents along the branches increase with the distance to the current feed point,and the more conductors near the injection point,the more uneven the leakage current distribution is.This work indicates that shielding effect should be taken into account when analyzing the impulse characteristics of grounding electrodes.
Correlation Analysis Algorithm for Transmission Line Fault Location Based on Travelling Wave

This paper introduced correlation method to locate transmission line fault.First it described the principle of transmission line fault location based on traveling waves.The principle of correlation analysis is introduced,then the method using correlation analysis in fault location is given.Transmission line model is established with EMTP-ATP.Basing on the model,some kinds of fault are simulated.The feasibility of this algorithm is proved based on simulation results.By comparing with the classical wavelet analysis,this paper gave the advantages of this algorithm in two cases:noise influence suppression and accuracy of near distance fault location.Experiment is established to simulate transmission line grounding fault.The experiment result showed the correlation algorithm's validity.All the analysis result indicated that the correlation algorithm have a high precision.
Flashover Characteristics of Flat Plate Model Under DC Voltage in Wind-sand Condition

The influence of sand dust on discharge of external insulation has caused widespread concern.At present,the research results show wind-sand electricity has a remarkable effect on the discharge characteristics of insulator and has little influence on the discharge characteristics of air gap.The flashover of insulator strings occurs along the insulator surface and air gaps,and the sand dust deposited on the insulator surface may affect the flashover characteristics of insulator strings.This paper studies the flashover characteristics of flat plate model under DC voltage in wind-sand condition.The experimental results show that under positive polarity voltage,the flashover voltage of the flat plate model has a maximum value,while under negative polarity voltage,the flashover voltage of the flat plate model has a minimum value with a certain degree of sand dust deposition.The wind or sand in sand-dust weather has an important effect on the flashover characteristics of the flat plate modelIn certain variation range of electric charge,electric charge of sand dust has little effect on the flashover voltage of flat plate model under DC voltage.The deposition of sand has significant influence on the flashover process of flat plate model,which is related to the deposition density and moisture content of sand particle.
Analysis of Conductors' Surface Electric Field of UHVDC Transmission Lines Based on Optimized Charge Simulation Method

The choice of the UHV lines depends on surface electric field of the bundle conductors.Based on existing calculation methods,the optimized charge simulation method is used to calculate the conductors' surface electrical field of±800 kV UHVDC transmission lines in this paper.During calculation,the offset distance is set as the variance of the objective function,the position and the quantity of the simulation charges are optimized with the gold section method,and the surface electrical field is calculated when the charge is in the optimal position.The result shows that the distribution of the surface electrical field and its maximal value can be calculated accurately with this method,although less number of simulation charges is used in this proposed method and the calculation is simple.
Test Study on Corona Onset Voltage of UHV Transmission Lines Based on UV Detection

Corona discharge is being detected by UV imaging detection technology at home and abroad in recent years.This technology is used in the corona tests of conductor bundles in this paper.In order to further research the corona characteristic,optimize geometry parameters and diameter of sub-conductor,and increase corona onset voltage of transmission lines,corona tests of three model conductors which are placed inside the outdoor corona cage are conducted.Corona cage could be used to simulate the corona activities on transmission lines under a low voltage and different conditions in an effective and economical way.Photon which was created by UV light as a result of corona discharge on conductors is detected by the UV detection apparatus.The photon number within unit interval,namely photon counting rate is adopted as the parameter of quantifying the intensity of corona discharge.According to the apparent change of photon number,corona onset voltage can be judged.All tests are conducted under almost same atmosphere condition.Using the method,corona onset voltage is acquired.The results indicate that the tests have a good repeatability,in other words,repeating same test twice same result can be aquired.The corona onset voltage can be acquired exactly from the curve of applied voltage vs.photon counting rate.Therefore UV detection apparatus can not only used to find discharge point exactly,but also applied on corona discharge research and live detection for power equipments.The method using in this paper is proved that is a new available method.
Application of Voltage Response Method to Condition Assessment of Power Transformer

Power transformer is one of the most important equipment in the power system.Its operating condition affects the reliability of power supply directly.Therefore,in order to guarantee transformer operation safely and reliably,it is necessary to assess condition of power transformer accurately.Return voltage method based on voltage response measurements is still a new non-intrusive diagnosis method for internal insulation aging of transformer.In this paper the technique and application of return voltage measurement and some results of voltage response measurements of several transformers was introduced.Voltage response measurements were performed on various transformers with different voltage grades,various operating periods,different moisture contents and aging degrees on site.Derived moisture contents from return voltage measurement were compared with the corresponding moisture contents obtained from the analysis of oil samples.Based on on-site experiments and theoretical analysis,the criteria for insulation state of transformer are proposed.Moisture condition of transformer insulation can be determined by using return dominant time constant,and a good correlation between aging degree and the return voltage initial slopes of the aged transformers.Field test performed on several transformers,its interpretation of results are also presented,which proves that return voltage measurements can be used as a reliable tool for evaluating moisture content in transformer insulation.
Aspects of High Voltage Cable Sections in Modern Overhead Line Transmission Systems

Electrical power transmission is dominated by overhead line systems at present.This is mainly based on more than hundred years of experience of utilities in running overhead lines.Furthermore,overhead lines have proven their operational reliability and functional assurance.In the past,cables were used in distribution networks in urban areas for the most part with the exception of direct current submarine cables.New developments of high voltage XLPE cables make it possible to use this technology for EHV level applications in transmission networks.Within this paper,mixed network configurations,consisting of overhead lines and high voltage cables,are investigated.An exemplary EHV transmission line with a total length of about 100 km,which is quite typical for Central Europe,has been studied.Several different line combinations are discussed with varied rates between overhead line sections and cable sections length in practice.The length of the cable sections are ranging from several kilometers up to lengths of 100 km.In this paper the work focuses on the transient behavior of combined 400 kV overhead and cable lines during switching processes and lightning impacts.A number of calculations were carried out to get an overview of the transient stress in numerous network nodes along the transmission system.Numerical programs like ATP/EMTP have been used for these simulations.Peak values and wave shapes of the transient voltage stress have been evaluated,based on different systems and within possible combinations.In respect of the insulation coordination and transient stress at network nodes,the voltage-time trends are also analyzed.The combination of high voltage overhead and cable transmission systems,especially such with lengths of more than about 50 km,are making tightened and extended demands to the network design,to the operational management and of course to the network protection also.As an output of this investigations,the results might influence the strategy in running this new type of combined transmission systems.
联合用药治疗3例重症肺鼠疫患者

链霉素应用以来,对鼠疫的治疗和控制起到了莫大的作用。迄今,链霉素仍为治疗鼠疫的首选特效药物,但由于在治疗中用量大,毒性反应重,过敏反应多,加之近年来国内外链霉素耐药菌株的发现,给鼠疫治疗带来了一定的困难。2004年在对青海省囊谦县3例重症肺鼠疫患者的治疗中,将头孢曲松钠、氧氟沙星与链霉素联合用药,收到满意效果,现报告如下。
“世界屋脊”大地形坡面探测同化信息对下游天气的预警效应

采用WRF模式多时间层三维变分同化技术(3DVAR),将青藏高原及其周边地区AWS自动气象站观测网多要素资料同化进数值模式的初始场,对发生于2008年1月中国南方及长江中下游特大雪灾天气进行数值模拟试验.由于青藏高原具有极其陡峭的大地形坡面,且高耸于对流层中部,故分布于高原大地形"坡面"不同高度的自动站网观测要素,将与无线电探空探测获取的大气"廓线"信息存在着某种程度的关联性,其不仅在观测点高度、梯度特征,而且在观测时间频数、"定点"、"定高"及其同步性等方面均具有不同于平原自动站、常规探空的特殊功能优势.高原大地形坡面自动站网信息同化场亦可提供高原东部下游天气系统高敏感区前兆性"强信号",并实现模式高原及周边区域初始场大气动力、热力三维结构客观化调整,从而提升下游区域灾害天气系统模拟与预报能力.研究表明,青藏高原及其周边地区自动站的水汽、温度、气压等资料同化信息对于预报下游区域的降水预报至关重要.
斯特林型脉管制冷机中的回热器温度不均匀性研究

回热器是脉管制冷机和热声热机中的最关键部件之一.当回热器由中小功率放大到大功率时,其内垂直于声传播方向的热力和水力联系变弱.在这种情况下,任何的非对称因素都可能在制冷机或发动机的回热器内引发严重的不稳定性问题,从而降低制冷机或发动机的性能.对一台大功率二级热耦合U型斯特林脉管制冷机进行了实验研究,通过对中间换热器和回热器周向温度分布进行测量,发现了一种由级间预冷不对称性引起的回热器温度不均匀性.观察发现,回热器周向的温度不均匀性源于第二级回热器的中间换热器,之后,这个温度不均匀性在回热器中以内部直流的形式自行放大,最大径向温差可达30~40K.在对第一级冷头外加热负荷并逐步增大热负荷直至把第一级的预冷效应转变为加热效应的过程中,回热器内的温度不均性逐渐变弱,最后其方向发生逆转.本研究证明了在大功率回热式热机中保持换热器加热或冷却作用周向均一的重要性.
A cold plasma plume with a highly conductive liquid electrode

A cold dielectric barrier discharge (DBD) plasma plume with one highly conductive liquid electrode has been developed to treat thermally sensitive materials, and its preliminary discharging characteristics have been studied. The averaged electron temperature and density is estimated to be 0.6eV and 1011/cm3, respectively. The length of plasma plume can reach 5 cm with helium gas (He), and the conductivity of the outer electrode affects the plume length obviously. This plasma plume could be touched by bare hand without causing any burning or painful sensation, which may provide potential application for safe aseptic skin care. Moreover, the oxidative particles (e.g., OH, O*, O3) in the downstream oxygen (O2) gas of the plume have been applied to treat the landfill leachate. The results show that the activated O2 gas can degrade the landfill leachate effectively, and the chemical oxygen demand (COD), conductivity, biochemical oxygen demand (BOD), and suspended solid (SS) can be decreased by 52%, 57%, 76% and 92%, respectively.
Synthesis and photoluminescence properties of Nd2O3 nanoparticles modified by sodium bis(2-ethylhexyl) sulfosuccinate

This paper reports that Nd_2O_3 nanoparticles modified by AOT(sodium bis(2-ethylhexyl) sulfosuccinate) were prepared using microemulsion method in the system of water and propanol/AOT/toluene. Transmission electron microscopy shows that the Nd_2O_3 nanoparticles take the shape of sphere with 18 nm and 31 nm with different preparation. The organic sol of Nd_2O_3 nanoparticles is very stable at room temperature. X-ray diffraction results show that the product has hexagonal phase structure. Two ultraviolet emission band at 344 nm and 361 nm corresponding to the transition of 4~D_(3/2) → 4 ~I_(9/2) and 2~P_(3 /2) →4~ I_(11/2) or 4~D_(3/2_ → 4~ I_(13/2_ were observed.
Relations between compositional modulation and atomic ordering degree in thin films of ternary III–V semiconductor alloys

This paper derives the expressions for the ordering degree and the modulation factor of A and B atoms in AxB1 - xC epilayers of ternary III–V semiconductor alloys. Using these expressions, it identifies quantitatively the alternating atom-enhanced planes, compositional modulations, atomic ordering degree on the group-III sublattices and the fine structure of NMR spectra.
浙江省遂昌县泥石流灾害遥感调查评价方法探讨

1前言浙江地处东南沿海,既是我国经济发达的省份,也是台风和暴雨频发地带。近年来因台风和暴雨导致的滑坡、泥石流等地质灾害,不仅威胁着人民生命财产安全,而且严重制约了区域经济的可持续发展。以小流域为调查尺度开展泥石流地质灾害调查与评价,查明小流域泥石流地质灾害的分布发育特征和危害程度,总结其发生发展和演化规律,评价小流域泥石流地质灾害易发程度和危险性,为各级政府科学制定防灾避险方案和城镇(村)规划,最大限度地避免和减少地质灾害损失,具有重要意义。卫星遥感技术是20世纪70年代发展起来的对地观测技术,具有覆盖面广、成本低、时效快、信息量大等特点,在泥石流灾害调查、评估、预警分析中具有广泛应用[1]。
基于OpenGL的虚拟机器人建模的优化方法

本文对OpenGL读取虚拟机器人模型的方法做出了优化。该方法分为三大步:第一步,利用常用三维建模软件构建虚拟机器人型;第二步,将这些三维模型转换为一种简单的"中间格式数据";第三步,利用OpenGL读取"中间格式数据"。实验表明,该方法在虚拟机器人建模中能大大降低建模的难度和复杂度,具有很强的实用性。
一种基于改进的ASM人脸特征定位技术

原始的主动形状模型(Active Shape Model,ASM)在很多方面得到了广泛的应用,如特征点定位,轮廓提取等。但是,原始ASM算法只采用灰度信息进行局部特征匹配,需要的训练样本多,存在精度不够高,鲁棒性不强的缺点。本文提出了一种融入彩色梯度特征的方法来改进原始ASM算法,并在IMM人脸库上进行对比实验,实验结果表明改进的算法性能比原始ASM算法有很大的提高。
高三学生的竞争态度及与心理健康状况的相关性

过度竞争易表现出较低的信任度和较强的占有欲,是一种不良的人格特质[1].高三学生面对学业、期望、个人成长等内外压力,易形成不良的竞争态度和心理症状.本文探讨高三学生竞争态度与心理健康的关系,以促进其身心和谐发展,也为适度竞争提供依据.
继往开来、重振我国电力电子器件研发领域的雄风--电力电子器件研发进展专辑特邀主编评述

电力电子器件作为电力电子技术的3个主要支撑点之一,其前进步伐在很大程度上决定着整个电力电子技术领域的发展。一代器件产生一代装置的论断不断被电力电子技术长足发展的历史所证实。
浙江省进口废物环境管理现状及对策研究

随着经济社会的快速发展、资源及原材料需求量的不断增加，可用于再生利用的废物进口量近年来大幅度增长，浙江省作为进出口条件相对便利的沿海省份，上述废弃物资的加工利用已逐步形成相当规模的产业市场，但随之带来的环境污染和各类“洋垃圾”事件也成为社会各界和媒体追逐的热点问题。文章详述了目前浙江省限制类进口废物环境管理的现状情况，根据存在的主要问题，提出了相应的对策建议，为浙江省进口废物环境监管提供指导依据，同时也对全国进口废物管理政策的制定提供技术支撑。
三个热带风暴登陆我国 四川遭受暴雨洪涝灾害——2008年9月

9月,全国平均气温为16.9℃,较常年同期(16.0℃)偏高0.9℃。全国平均月降水量为64.8mm,接近常年同期(65.4mm);广西、青海月降水量为1951年以来历史同期第3多。9月,台风森拉克、蔷薇和黑格比登陆我国;部分省市区遭受暴雨袭击,局地发生洪涝及滑坡、泥石流灾害;新疆北部、黑龙江大部气象干旱到不不同程度缓和,局地遭到雷雨大风,冰雹等强对流天气袭击,华南,江南等地出现高温天气.
江南华南出现高温 三个台风登陆我国——2008年9月

2008年9月,全国平均气温较常年同期偏高,其中,福建、广东、海南的平均气温为1951年以来历史同期最高。全国平均月降水量接近常年同期;广西、青海月降水量为1951年以来历史同期第3多。月内下旬中后期南方部分地区出现寒露风天气;台风“森拉克”、“蔷薇”和“黑格比”登陆我国.
潮湿环境下非氢类金刚石薄膜的超自润滑性能研究

采用脉冲激光沉积(PLD)方法在不同衬底温度条件下制备了不含氢的类金刚石薄膜,在相对湿度为80%与5%的条件下测试了类金刚石薄膜的摩擦学特性.由于PLD方法的独特性,薄膜具"软-硬"双层结构,保证了薄膜在潮湿条件(RH=80%)下仍保持非常优异的摩擦性能,摩擦系数与磨损率最低达0.045与5.94×10~(-10)mm~3·N~(-1)·m~(-1),相对于干燥条件下测试结果来看,几乎没有明显变化.原子力显微镜与白光干涉仪测试结果表明,薄膜的均方根粗糙度小于1nm,最小值为0.209nm;XPS表明薄膜sp~3最高含量达72%,并且Raman光谱结果表明室温下制备的薄膜是非晶网络结构;纳米压痕迹测试表明,薄膜最高硬度与弹性模量分别达51GPa与350GPa,且随衬底温度升高而降低;样品表面的水接触角均大于90°,薄膜表面疏水并具有极低的表面能.