检索结果-内蒙古大学图书馆

Asia-Pacific International Conference on Lightning (APL)

作者： Shanqiang Gu Nianwen Xiang Jiahong Chen Weijiang Chen Shijun Xie Junjia He The State Grid Electric Power Research Institute Wuhan China State Grid Corporation of China Beijing China The State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan China

The geometric form of the leader trajectory is an interesting aspect of long air gap discharge research. In this paper, the 3-D discharge channel tortuosity in 3m rod-plane gaps is obtained by following steps: Firstly, using two static cameras fixed orthogonally to record the face photo and the side photo of the discharge channel. Secondly, the 3-D discharge channel is reconstructed by employing image recognition technology. Thirdly, the discharge channel tortuosity in two-dimensional space and three-dimensional space are derived respectively, which satisfied the Gaussian distribution law. The statistical results indicate that the channel tortuosity will be conservatively estimated by using a two-dimensional method. Statistical results of the channel tortuosity with three-dimensional method indicate the following conclusions. The angle between the discharge channel segments and the gap axis meets the distribution of rational function and its average value and standard deviation is 23.8° and ±19.0° respectively; the angle between the adjacent channel segments also meets the distribution of rational function, and its average value and standard deviation is 13.3° and ±9.9°.

关键词： Discharges Image reconstruction Sparks Probability Cameras Time frequency analysis Face

来源：评论

学校读者我要写书评

暂无评论

A Visible Light Imaging System for the Estimation of Plasma Vertical Displacement in J-TEXT

引用

Plasma Science and technology 2010年第6期12卷 641-645页

作者：朱孟周庄革王之江丁永华高丽胡希伟潘垣 College of Electrical and Electronic Engineering Huazhong University of Science and Technology China Key Laboratory of Fusion and Advanced Electromagnetic Technology of Ministry of Education

A wide-viewing-angle visible light imaging system （VLIS） was mounted on the Joint Texas Experimental Tokamak （J-TEXT） to monitor the discharge process. It is proposed that by using the film data recorded the plasma vertical displacement can be estimated. In this paper installation and operation of the VLIS are presented in detailed. The estimated result is further compared with that measured by using an array of magnetic pickup coils. Their consistency verifies that the estimation of the plasma vertical displacement in J-TEXT by using the imaging data is promising.

关键词： visible light imaging, vertical displacement J-TEXT

来源：评论

学校读者我要写书评

暂无评论

Soft X-ray Pulse Height Analysis System on J-TEXT Tokamak

Soft X-ray Pulse Height Analysis System on J-TEXT Tokamak

引用

第十五届全国等离子体科学技术会议

作者： W.Jin G.Zhuang Y.H.Ding Y.Zhang J.Zhang Z.Y.Chen S.Y.Lin P.Xu W.Kong State Key Laboratory of Advanced Electromagnetic Engineering and Technology CHINA-USA Joint Fusion Laboratory J-TEXT. College of Electric and Electronic Engineering Huazhong University of Science and Technology Wuhan 430074 China Institute of Plasma Physics Chinese Academy of Science. Hefei 230031China Department of Modern Physics University of Science and Technology of China Hefei 230026China

A soft X-ray pulse height analysis (PHA) system has been designed and installed on J-TEXT tokamak for the study of electron temperature and *** system contains three Silicon Drift Detectors (SDD),a multi-channel analyzer (MCA),vacuum chamber,data collection procedure and off-line data processing program.A 60ms temporal resolution of electron temperature and the line radiation from moderate and high Z metallic impurities can be obtained by PHA *** on this SyStcm the performances of electron temperature and impurity have been investigated in J-TEXT ohmic heated plasmas.

关键词： soft-x-ray PHA J-TEXT

来源：评论

学校读者我要写书评

暂无评论

适用于海上风场并网的混合多端直流输电技术研究

适用于海上风场并网的混合多端直流输电技术研究

引用

2012年中国智能电网学术研讨会

作者： WEN Jin-yu 文劲宇 CHEN Xia 陈霞 YAO Mei-qi 姚美齐 LI Nai-hu 李乃湖 SUN Shu-min 孙树敏 LI Guang-lei 李广磊 State Key Laboratory of Advanced Electromagnetic Engineering and Technology(AEET) (School ot Electri 强电磁工程与新技术国家重点实验室(华中科技大学电气与电子工程学院) 湖北武汉430074 ALSTOM Grid Technology Center(China)Co. LtdShanghai 201114China 阿尔斯通电网技术中心(中国)有限公司上海201114 Shandong Electric Power Research Institute Jinan 250002China 山东电力集团公司电力科学研究院山东济南250002

针对海上风电并网的需求,提出了采用VSC换流器连接海上风场和弱受端交流系统,LCC换流器连接较强交流系统的混合多端直流输电系统拓扑结构,并对一个混合5端直流输电系统进行了详细研究。分析了5个换流器的电压电流控制特性,设计了直流系... 详细信息

针对海上风电并网的需求,提出了采用VSC换流器连接海上风场和弱受端交流系统,LCC换流器连接较强交流系统的混合多端直流输电系统拓扑结构,并对一个混合5端直流输电系统进行了详细研究。分析了5个换流器的电压电流控制特性,设计了直流系统控制策略,研究了系统在风速波动、逆变侧VSC和LCC分别出现三相短路故障以及直流线路故障时系统的动态响应特性。仿真结果表明所提出的混合多端直流输电系统具有较好的运行特性,可以适应海上风电并网的需求。

关键词：海上风电并网混合多端直流输电技术换流器仿真分析

来源：评论

学校读者我要写书评

暂无评论

Study on Voltage Maintaining Performance of Metalized Film Capacitors under High Electric Fields

Study on Voltage Maintaining Performance of Metalized Film C...

引用

Annual Report Conference on Electrical Insulation and Dielectric Phenomena

作者： Hua Li Yaohong Chen Fuchang Lin Fei Lv Zhiwei Li Miao Zhang State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan Hubei P. R. China 430074

ISBN: (纸本)9781457709852

The metalized film capacitor can work under a high electric field due to its self-healing characteristic. But when the capacitor is charged rapidly to a specified high voltage (under a high electric field) and then it is disconnected from the power supply, a significant voltage drop will be observed, so the capacitor energy efficiency will reduce. It can be observed that the general curve of the voltage decay has a rapid initial drop and then the curve can usually be fit to a pure exponential. Firstly, this paper analyses the factors which cause the voltage decay through experimental study. The research results show that electric field strength, operating temperature and hold time play important roles in the voltage decay process. The higher the electric field or operating temperature is, the more significant the voltage drop is. If the voltage of the capacitor is maintained for a specified period of time, the voltage drop will reduce significantly. Through these experimental results, it is revealed that the voltage drop is mainly related to leakage and polarization. So the insulation resistance at various temperatures under high electric field is tested by the special technique. The results of insulation resistances are consistent with the voltage decay at various temperatures. Moreover, the interfacial polarization which exists in the charging process of metalized film capacitor is discussed. The interfacial polarization causes the rapid initial voltage decay.

关键词： Metalized Capacitors Maintaining

来源：评论

学校读者我要写书评

暂无评论

A numerical simulation of surface wave excitation in a rectangular planar-type plasma source

引用

Chinese Physics B 2009年第8期18卷 3484-3489页

作者：陈兆权刘明海蓝朝晖陈伟唐亮罗志清燕保荣吕建红胡希伟 Key Laboratory of Fusion and Advanced Electromagnetic Technology of Ministry of Education College of Electrical & Electronic EngineeringHuazhong University of Science and Technology

The principle of surface wave plasma discharge in a rectangular cavity is introduced simply based on surface plasmon polariton theory. The distribution of surface-wave electric field at the interface of the plasma-dielectric slab is investigated by using the three-dimensional finite-difference time-domain method （3D-FDTD） with different slotantenna structures. And the experimental image of discharge with a novel slot antenna array and the simulation of the electric field with this slot antenna array are both displayed. Combined with the distribution of surface wave excitation and experimental results, the numerical simulation performed by using 3D-FDTD is shown to be a useful tool in the computer-aided antenna design for large area planar-type surface-wave plasma sources.

关键词： surface wave plasma numerical simulation three-dimensional finite-difference time domain method surface plasmons polaritons

来源：评论

学校读者我要写书评

暂无评论

Supervised Raman spectra estimation based on nonnegative rank deficient least squares

Supervised Raman spectra estimation based on nonnegative ran...

引用

International Conference on Information Fusion

作者： Barry Drake Jingu Kim Mahendra Mallick Haesun Park Sensors and Electromagnetic Applications Laboratory Georgia Tech Research Institute Georgia Institute of Technology Atlanta GA USA School of Computational Science and Engineering Georgia Institute of Technology Atlanta GA USA School of Computational Sciences Korea Institute of Advanced Study Seoul South Korea

Raman spectroscopy is a powerful and effective technique for analyzing and identifying the chemical composition of a substance. In this paper, we focus on supervised methods for estimating Raman spectra and present a supervised method that can handle rank deficiency for estimating the Raman spectra. Earlier work has mostly assumed that the reference spectra matrix whose columns consist of the library of reference spectra are of full rank. However in practice, methods that can handle rank deficient cases, and the special case of an over complete library, are needed. We present our theoretical discovery that the active set method with a proper starting vector can actually solve the rank deficient nonnegativity-constrained least squares problems without ever running into rank deficient least squares problems during iterations. Experimental results illustrate the effectiveness of the proposed approaches.

关键词： Chemicals Least squares approximation Estimation Raman scattering Indexes Photonics Charge coupled devices

来源：评论

学校读者我要写书评

暂无评论

The J-TEXT Tokamak Control System

The J-TEXT Tokamak Control System

引用

International Conference on Electronic Computer technology

作者： Zhoujun Yang Ge Zhuang Xiwei Hu Ming Zhang Shengshun Qiu College of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China Key Laboratory of Fusion and Advanced Electromagnetic Technology of Ministry of Education Wuhan China

ISBN: (纸本)9781424435623

The J-TEXT tokamak is a complex experiment facility. Its running refers many subsystems, such as various power supply systems, a gas puffing system, many diagnostic systems, a safety protection system, etc. So it asks for a control system to manage the process of discharge. This paper presents the functions of control system for the J-TEXT tokamak, describes its structure, and introduces the realization based on QNX real time operating system. Results obtained demonstrate that the control system handles the discharge process perfectly. However, it will be continued to improve to meet much more requirement and get more perfect performance.

关键词： Tokamaks Control systems Communication system control Educational technology Power supplies Safety Power system protection Real time systems Operating systems Plasma density

来源：评论

学校读者我要写书评

暂无评论

Estimation of Plasma Density by Surface Plasmons for Surface-Wave Plasmas

引用

Chinese Physics Letters 2008年第12期25卷 4333-4335页

作者：陈兆权刘明海蓝朝晖陈伟罗志清胡希伟 Key Laboratory of Fusion and Advanced Electromagnetic Technology of Ministry of Education College of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan 430074

An estimation method of plasma density based on surface plasmons theory for surface-wave plasmas is proposed. The number of standing-wave is obtained directly from the discharge image, and the propagation constant is calculated with the trim size of the apparatus in this method, then plasma density can be determined with the value of 9.1 × 10^17m^-3. Plasma density is measured using a Langmuir probe, the value is 8.1 × 10^17m^-3 which is very close to the predicted value of surface plasmons theory. Numerical simulation is used to check the number of standing-wave by the finite-difference time-domain （FDTD） method also. All results are compatible both of theoretical analysis and experimental measurement.

关键词： field emission molybdenum dioxide enhancement factor

来源：评论

学校读者我要写书评

暂无评论

Mode suppressed TEM cell design for high frequency IC measurements

Mode suppressed TEM cell design for high frequency IC measur...

引用

IEEE International Symposium on electromagnetic Compatibility, EMC 2007

作者： Deng, Shaowei Pommerenke, David Hubing, Todd Drewniak, James Beetner, Daryl Shin, Dongshik Kim, Sungnam Kwak, Hocheol Electromagnetic Compatibility Laboratory University of Missouri-Rolla Rolla MO United States Advanced Electronic Packaging Technology Group Production Engineering Research Center LG Electronics Korea Republic of

ISBN: (纸本)1424413508

TEM cells or GTEM cells can be used to evaluate the radiated emissions of integrated circuits (ICs). The applicable frequency bandwidth of a TEM cell is limited due to the resonances of higher order modes. This paper describes how a TEM cell can be modified to extend the frequency range without changing the test topology. Several methods are proposed and implemented to suppress the higher order modes. The magnetic field coupling and electric field coupling are evaluated for the new design. The frequency bandwidth of the modified TEM cell is extended from original 1 GHz to 2.5 GHz. ©2007 IEEE.

关键词： Integrated circuits

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：