检索结果-南通市图书馆

High Voltage 2024年第1期9卷 22-34页

作者： Haichuan Yu Qiang Liu Zhongdong Wang Department of Electrical and Electronic Engineering The University of ManchesterManchesterUK Department of Engineering University of ExeterExeterUK

Ester liquids(ELs),as the alternative transformer liquids to the conventional mineral oils(MOs),have been increasingly used in power transformers with high voltage ratings.Among various properties,the lightning impulse breakdown voltages(LIBDVs)have been studied elaborately in the past two decades under different electric Field uniformities.The electric Field uniformities do have an effect on the breakdown characteristics,for example,breakdown mechanisms,polarity effects,and differences of LIBDV between ELs and MOs,which is quantitatively investigated based on the LIBDVs collected from the literatures.The breakdown mechanism transition phenomenon between streamer initiation dominated breakdown and streamer propagation dominated breakdown has been reviewed firstly.Then,the transition Field factor boundaries to observe the polarity effect on LIBDVs are taken at around 20 for ELs and 10 for MOs.Besides,the transition Field factor boundaries to observe the LIBDV distinctions between ELs and MOs are about 109 and 14 under positive and negative lightning impulse,respectively.The systematic analysis and interpretation on the transition Field factor boundaries among different phenomena can provide insights on insulation design of ELs filled power transformers.

关键词： Field lightning breakdown

Influence of positive DC electric Field on rime icing on the insulator and its experimental verification in the natural environment

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High Voltage 2023年第5期8卷 954-966页

作者： Zongyuan Liu Yuyao Hu Xingliang Jiang Lei Chen Mingchen Chi Feiyan Han Chong Zhao College of Electrical and Electronic Engineering Shandong University of TechnologyZiboChina State Key Laboratory of Power Transmission Equipment&System Security and New Technology Chongqing UniversityChongqingChina

The electric Field imposes a significant effect on ice accretion on the insulator.The impact of an AC electric Field on insulator icing in an artificial climate chamber has been addressed.Compared with AC,DC electric Field exerts an attraction on supercooled water droplets,which is more detrimental to the power system.Moreover,the icing on energised insulators is rarely studied in the natural environment.In the present research,an electrical,fluid coupled‐Field simulation was carried out on the insulator.The force characteristics and motion deviation features of water droplets at different positive DC electric Field strengths were studied.On this basis,rime icing on the insulator energised with different positive DC voltages was investigated in the Field.Results show that the charged droplet shifts along the electric Field line under a positive DC voltage.The deviation degree of the droplet increases with the increment of the voltage and droplet size and decreases with an increase in wind speed.As the voltage rises,the surface roughness,icing amount and icing length of rime ice‐covered insulator increase.Consequently,compared with that without energisation,the local collision coefficient,icing amount and icing length increase by 17.6%,46.4%and 63.9%,respectively,under a 40 kV DC voltage.

关键词： insulator Field positive

A promising approach to steady-state fusion: High-temperature superconducting strong-Field stellarator with precise omnigenity

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The Innovation 2024年第1期5卷 23-25页

作者： Guosheng Xu Zhiyuan Lu Dehong Chen Baonian Wan Institute of Plasma Physics Chinese Academy of SciencesHefei 230031China

The stellarator has inherent advantages over the tokamak in achieving steady-state operation,especially due to its absence of disruptions and lack of need for current drive and the associated recirculating power.In recent years,there have been remarkable advances in the Field of stellarator optimization,where precisely quasi-symmetric and precisely quasi-isodynamic magnetic configurations have been achieved with coils,allowing the neoclassical transport and energetic particle losses of stellarators to be reduced to levels comparable to those of tokamaks.At the same time,the development of high-temperature superconducting magnet technology will potentially double the magnetic Field strength of stellarators.While these strong Fields are expected to introduce new challenges,and while turbulent transport remains a common challenge for both stellarators and tokamaks,the combination of these physical and technological advances results in the expectation that stellarators will become a competitive approach to tokamaks for realizing steady-state fusion.

关键词： Field approach precise

Modelling on thermal-fluid Field in SF_(6)insulated high voltage direct current bushing with its influence on electric Field distribution and metal particle motion

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High Voltage 2023年第2期8卷 380-389页

作者： Xiao Yang Yi Zhang Zhuodong Yang Hao Dong Chengrong Li Bo Qi Licheng Lu Caixin Sun State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijingChina Global Energy Interconnection Research Institute Co Ltd BeijingChina China Huaneng Group Co Ltd BeijingChina

The insulation performance of SF_(6)insulated high voltage direct current apparatus are often analysed in a pure electric Field or electro-thermal coupled Field while the fluid behaviour of SF_(6)gas flow is often ignored.However,frequent flashover along the support insulators inside the SF_(6)insulated wall bushing indicates that the fluid characteristics of SF_(6)may have considerable influence on the interior insulation performance of the bushing.This paper has simulated the thermo-fluid coupled Field in the SF_(6)insulated wall bushing based on the finite element method model.The result shows that buoyant flow of SF_(6)has evident influence on the temperature distribution in the bushing.On this basis,the effect of the thermo-fluid Field on the electric Field distribution along the insulator as well as on the motion behaviour of the metallic particles is analysed.Furthermore,the effect of different thermal boundary conditions on analysis of the multiphysics Field in the bushing is discussed and the most suitable one for simulation and experiment is suggested.Comparisons are made between different supporting structures and modification advices are proposed.This paper can serve as a good reference for subsequent research studies on SF_(6)insulated apparatus in which the temperature gradient or the motion of the micro-sized metallic particles shall be considered.

关键词： distribution thermal Field

Bridging boundaries: On the contributions of Dr. Michael Plewa to the disinfection byproduct Field

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2022年第7期34卷 3-5页

作者： William A.Mitch Department of Civil and Environmental Engineering Stanford UniversityCalifornia 94305USA

Why is a Professor in the Department of Crop Sciences such a dominant presence in the Field of disinfection byproducts(DBPs)? I believe the answer to this question exemplifies the characteristics of impactful researchers. Most research Fields rely on a set of core skills and tend to develop tunnel-vision with respect to research topics. These factors can be stultifying for the Field, but present opportunities to those in other Fields with the vision and fortitude to span research Fields and fill unoccupied niches where their approach and skillset is needed and lacking.

关键词： Field occupied tunnel

Realisation of the reconfigurable pulsed high magnetic Field facility and its scientific application at Wuhan National Pulsed High Magnetic Field Centre

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High Voltage 2023年第5期8卷 898-906页

作者： Jianfeng Xie Shaozhe Zhang Jiangtao Shi Junfeng Wang Liang Li Xiaotao Han Wuhan National High Magnetic Field Center Huazhong University of Science and TechnologyWuhanChina State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and TechnologyWuhanChina

To generate arbitrary shape magnetic Field waveforms for advanced scientific research,a reconfigurable pulsed high magnetic Field facility(PHMFF)was developed at Wuhan National Pulsed High Magnetic Field Centre(WHMFC).First,the basic elements of PHMFF are introduced,and a ternary physical model composed of energy storage unit,magnet,transmission circuits and other auxiliary units is summarised to describe various magnetic Field systems.Second,in order to realise the reconfiguration of magnetic Field systems based on detailed elements,the control system with the ability of dynamic construction and control sequence reconfiguration is designed.On this basis,the PHMFF has been realised and various magnetic Field systems are constructed to produce arbitrary shape magnetic Field waveforms,such as half‐sine,ultra‐high,flat‐top and repetitive Field pulses,which not only enhances the capability and efficiency of PHMFF,but also makes more scientific research possible in pulsed magnetic Fields.So far,a peak magnetic Field of 94.8 T,a flat‐top magnetic Field of 64 T/10 ms and a repetitive magnetic Field waveform of 20 T/60 Hz have been achieved,and some experiments and studies on the physical properties of materials have been carried out at WHMFC.

关键词： magnetic Field pulsed

Experimental and numerical simulation study on the erosion behavior of the elbow of gathering pipeline in shale gas fi eld

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

PETROLEUM SCIENCE 2024年第2期21卷 1257-1274页

作者： Liu, En -Bin Huang, Shen Tian, Ding-Chao Shi, Lai-Min Peng, Shan-Bi Zheng, He Southwest Petr Univ Petr Engn Sch Chengdu 610500 Sichuan Peoples R China Chongqing Nat Gas Sales Ctr Nat Gas Branch Sinopec Chongqing 400023 Peoples R China Zhejiang Zheneng Nat Gas Operat Co Ltd Hangzhou 310000 Zhejiang Peoples R China Southwest Petr Univ Sch Civil Engn & Architecture Chengdu 610500 Sichuan Peoples R China Louisiana Tech Univ Trenchless Technol Ctr 599 Dan Reneau Dr Ruston LA 71270 USA Nat Gas Res Inst Southwest Oil & Gas Field Branch Chengdu 610213 Sichuan Peoples R China

During the production period of shale gas, proppant particles and rock debris are produced together, which will seriously erode the elbows of gathering pipelines. In response to this problem, this paper takes the elbow of the gathering pipeline in the Changning Shale Gas Field as an example to test the erosion rate and material removal mechanism of the test piece at different angles of the elbow through experiments and compares the four erosion models with the experimental results. Through analysis, it is found that the best prediction model for quartz sand-carbon steel erosion is the Oka model. Based on the Oka model, FLUENT software was used to simulate and analyze the law of erosion of the elbow of the gas gathering pipeline under different gas flow velocities, gas gathering pressure, particle size, length of L1, and bending directions of the elbow. And a spiral pipeline structure is proposed to reduce the erosion rate of the elbow under the same working conditions. The results show that this structure can reduce erosion by 34%. (c) 2023 The Authors. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://***/licenses/by-nc-nd/ 4.0/).

关键词： Shale gas Gas gathering pipeline Elbow Erosion CFD IMPACT PARTICLES VELOCITY STEEL Field FLOW

Electric-Field control of topological spin textures in BiFe_(O3)/La_(0.67)Sr_(0.33)MnO_(3)heterostructure at room temperature

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2023年第2期42卷 399-405页

作者： Ai-Ji Wang Liang Yang Jian Ge Gong-Xun Deng Yu-Ben Yang Jing-Di Lu Yue-Lin Zhang Yin-Shu Wang Hai-Ming Yu Ling-Fei Wang Ce-Wen Nan Jin-Xing Zhang Department of Physics Beijing Normal UniversityBeijing100875China Hefei National Research Center for Physical Sciences at the Microscale University of Science and Technology of ChinaHefei230026China Fert Beijing Institute MIIT Key Laboratory of SpintronicsSchool of Integrated Circuit Science and EngineeringBeihang UniversityBeijing100191China State Key Lab of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing100084China

Electric-Field control of topological magnetic states in thinfilm heterostructures is promising for applications in nextgeneration memory or logic devices with ultrahigh density and low-power consumption.Multiferroic materials,where spin and polar degrees of freedom coexist,provide a versatile playground to manipulate magnetism(converse magnetoelectric effect).Here,we report that the topological spin textures can be controlled by electric Field in rhombohedral BiFeO_(3)/monoclinic La_(0.67)Sr_(0.33)MnO_(3)thin-film heterostructure at room temperature.

关键词： temperature textures Field

维普期刊数据库

Conversion efficiency of strained wurtzite In_(x)Ga_(1-x)N/ZnSnN_(2)core/shell quantum dot solar cells under external electric Field

在线全文

学校读者我要写书评

暂无评论

Optoelectronics Letters 2023年第3期19卷 144-150页

作者： ZHANG Jun SHI Lei YAN Zuwei College of Science Inner Mongolia Agricultural UniversityHohhot 010018China

In this study,the conversion efficiency(CE),open-circuit voltage(V_(OC))and short-circuit current density(J_(SC))of wurtzite In_(x)Ga_(1-x)N/ZnSnN_(2)core/shell quantum dot(QD)solar cells are studied by using the detailed balance model.The effects of strain and external electric Field have been considered.The results show that with the increase of the core size,the V_(OC)increases,while the J_(SC)and CE decrease.With the increase of shell size or In content,the V_(OC)decreases,while the J_(SC)and CE increase.In addition,our calculations show that the band gap of QD increases due to strain,which leads to an increase of the V_(OC),but decreases of the CE and J_(SC).By contrast,the situation is opposite under the effect of external electric Field.

关键词： quantum strained Field

维普期刊数据库

Vector meson spin alignment by the strong force Field

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2023年第1期34卷 172-174页

作者： Xin‑Nian Wang Lawrence Berkeley National Laboratory Nuclear Science Division MS 70R0319BerkeleyCalifornia 94720USA Physics Department University of CaliforniaBerkeleyCalifornia 94720USA

Observation of unexpectedly large global spin alignment of φ vector mesons in non-central heavy-ion collisions by STAR experiment may reveal the non-perturbative nature of quark interaction in hot matter through fluc... 详细信息

关键词： meson alignment Field

维普期刊数据库