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A study of pulsed high voltage driven hollow-cathode electron beam sources through synchronous optical trigger

Plasma Science and technology 2024年第5期26卷 82-90页

作者：霍卫杰贺伟国韩罗峰朱康武王锋 Shanghai Aerospace Electronic Technology Institute Shanghai 201109People’s Republic of China School of Mechatronic Engineering and Automation Shanghai UniversityShanghai 200444People’s Republic of China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced StudyUniversity of Chinese Academy of SciencesHangzhou 310024People’s Republic of China Key Laboratory of Gravitational Wave Precision Measurement of Zhejiang Province Taiji Laboratory for Gravitational Wave UniverseHangzhou 310024People’s Republic of China Shanghai Aerospace Control Technology Institute Shanghai 201109People’s Republic of China

In this study,a pulsed,high voltage driven hollow-cathode electron beam sources through an optical trigger is designed with characteristics of simple structure,low cost,and easy *** validate the new design,the characteristics of hollow-cathode discharge and electron beam characterization under pulsed high voltage drive are studied experimentally and discussed by discharge characteristics and analyses of waveform details,*** validation experiments indicate that the pulsed high voltage supply significantly improves the frequency and stability of the discharge,which provides a new solution for the realization of a high-frequency,high-energy electron beam *** peak current amplitude in the high-energy electron beam increases from 6.2 A to 79.6 A,which indicates the pulsed power mode significantly improves the electron beam ***,increasing the capacitance significantly affects the highcurrent,lower-energy electron beam more than the high-energy electron beam.

关键词： hollow-cathode nanosecond pulsed electron beam sources optical trigger pulsed high voltage supply beam current distribution

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Investigation on the Direct Current Coefficient of I/V Transducer

Investigation on the Direct Current Coefficient of I/V Trans...

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International Conference on Electronic measurement and Instruments, ICEMI

作者： Liren Zhou Li Zhu Ji Geng Shanghai Key Laboratory of On-line Testing and Control Technology Shanghai Institute of Measurement and Testing Technolog Shanghai China

Direct current coefficient is an essential parameter of I/V transducer, which directly affects the measurement results. Traditional method, comparing the measured transducer with the standard transducer, has limitations; failure to solve the problem in essence. To measure the direct current coefficient accurately, a measuring device was developed, which consists of direct current source, standard direct current ratio, adjustable standard direct current ratio, standard I/V transducer, voltage meter and null indicator. A measurement method was proposed, which fixes the value of direct current source and current flowing through the standard I/V transducer; adjusts the current through the high accuracy ratio conversion. The error measurement principle was employed to minimize the influence on the measurement results. Measure the current coefficient of an I/V transducer and restore its actual working state. The result shows that the current coefficients in the four current ranges are all negative, and are basically in the order of 10 −5 . The proposed method is characterized by breaking dependence on the superior standard device and meets the needs of precise measurement result correction.

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A Novel Corrugated Horn Antenna for Compact Field measurement

A Novel Corrugated Horn Antenna for Compact Field Measuremen...

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International Conference on Microwave and Millimeter Wave technology Proceedings

作者： Zuojiansheng Zuojiansheng Chen Chaochan Wuzhuang Wuzhuang Shanghai Institution of Measurement and Testing Technology Shanghai Key Laboratory of On-Line Testing and Control Technology Shanghai Institution China

In this paper, a novel corrugated horn antenna is developed in a wide frequency ranges from 40 GHz to 60GHz ,which is used to evaluate performance of the compact field. After simulation and optimization, a novel manufactured corrugated horn antenna is developed, the main data of which show great consistency with simulated data in parameters of standing-wave coefficient, radiation pattern and radiation gain. In the end, the developed corrugated horn antenna is used to evaluate the performance of compact field, which meet the measurement needs.

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Numerical Study on Magnetic Field Characteristics of Electromagnetic Flowmeter with Small Excitation Module 21

Numerical Study on Magnetic Field Characteristics of Electro...

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5th International Conference on control Engineering and Artificial Intelligence, CCEAI 2021

作者： Yao, Xinhong Li, Xuejing Shanghai Institute of Measurement and Testing Technology Shanghai Key Laboratory of On-line Testing and Control Technology China

ISBN: (纸本)9781450388870

Electromagnetic flowmeter (EMFM) plays an important role in many production processes such as industry, medicine and agriculture. According to the measurement principle, the traditional electromagnetic flowmeter must have a large-size excitation module to provide a uniform magnetic field. However, this structure limits the use of electromagnetic flow meters. The saddle coil design has certain applications in electromagnetic flow sensors. The geometric size of the saddle coil is smaller than the Helmholtz coil and other large coils, so it has certain advantages in practical applications. But it causes the inhomogeneity of the induced magnetic field, which affects the measurement accuracy. This paper analyzes a saddle-shaped excitation module. An extended theory with a small magnetized flowmeter is proposed and compared with the experimental results. The electromagnetic field solution of the finite element program is proposed. The results of this study have certain guiding significance for the design process of the electromagnetic flowmeter excitation coil. © 2021 ACM.

关键词： Magnetic fields

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Research on electromagnetic flowmeter measurement of non-full pipe flow based on numerical analysis method

Research on electromagnetic flowmeter measurement of non-ful...

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IEEE Information technology, Networking, Electronic and Automation control Conference

作者： Xuejing Li Zhongli Zhang Shanghai Institute of Measurement And Testing Technology Shanghai China Shanghai Key Laboratory of On-Line Testing and Control Technology Shanghai China

The measurement of non-full pipe uniform flow with circular section is the focus of energy saving and emission reduction and government regulation. In order to study the accurate measurement of non-full flow, a three- dimensional mathematical model was established, and the boundary conditions were determined. Based on the velocity distribution characteristics of non-full flow section, an electromagnetic non-full flow measurement device is constructed. Set up the non-full flow calibration device in the laboratory, and carry out the experiment of real flow measurement in the laboratory. In order to ensure the accuracy of non-full tube flow measurement, the flow stabilizing device and non-full tube electromagnetic flowmeter are designed based on the study of the flow field distribution of non-full tube flow. The experimental results show that the error is less than 1.3% and the expanded uncertainty is U = 0.025% (K = 2) . The simulation model and parameter selection are also verified by the experimental results.

关键词： Uncertainty measurement uncertainty Flowmeters Boundary conditions Mathematical models Regulation Electron tubes

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Research on weight function distribution method under special boundary based on electrical characteristics

Research on weight function distribution method under specia...

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IEEE Information technology, Networking, Electronic and Automation control Conference

作者： Xuejing Li Xinhong Yao Shanghai Institute of Measurement And Testing Technology Shanghai China Shanghai Key Laboratory of On-Line Testing and Control Technology Shanghai China

The correct solution of weight function is very important to the analysis of induced potential distribution. In this paper, the weight function under the special boundary of Laplace equation is simulated and studied. Firstly, the boundary conditions are studied by using the electrical characteristics of the electromagnetic flowmeter sensor. Secondly, the weight functions of different conductivity and thickness measuring tubes are analyzed. Finally, the analysis conclusions are verified from the perspective of experiments. The research conclusion proves the correctness and validity of the research theory based on the special boundary weight function of electrical characteristics. The analysis method in this paper is of great significance in studying the influence of electromagnetic flowmeter wall contamination and electrode contamination on the weight function.

关键词： Electrodes Weight measurement Conductivity Flowmeters Pollution measurement Electron tubes Electromagnetics

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Research on a Three-phase Flow Electromagnetic measurement Method 4

Research on a Three-phase Flow Electromagnetic Measurement M...

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2020 4th International Conference on Energy Material, Chemical Engineering and Mining Engineering, EMCEME 2020

作者： Li, Xuejing Li, Haiyang Shanghai Institute of Measurement and Testing Technology Shanghai Key Laboratory of On-line Testing and Control Technology Shanghai China

For a long time, industrial and agricultural production has a wide range of requirements for energy saving and emission reduction. The flow parameter detection of water/gas/oil three-phase flow is of great significance in the control and optimization of the petroleum industry process. Using the principle of correlation method, a multi-electrode electromagnetic measurement method is designed to measure the three-phase flow. The system has the function of self-detection of the meter zero point. The finite element method is used to calculate and analyze the distribution of sensitive fields inside the flow measurement sensor and the influence of different physical parameters of non-conductive objects on the disturbance characteristics of the flow measurement sensor. And through experiments to prove the feasibility, stability and accuracy of the constructed measurement system. © 2021 Published under licence by IOP Publishing Ltd.

关键词： Flow measurement

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Study on A-GNSS Terminal Over-The-Air Test System 15

Study on A-GNSS Terminal Over-The-Air Test System

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15th IEEE International Conference on Electronic measurement and Instruments, ICEMI 2021

作者： Wang, Yunling Cai, Qing Xu, Jie Shanghai Institute of Measurement and Testing Technology Shanghai Key Laboratory of On-line Testing and Control Technology Shanghai China

ISBN: (纸本)9781665444910

The A-GNSS terminal Over-The-Air (OTA) test system is a system for OTA performance of terminals that support A-GNSS. Terminals supporting A-GNSS can search for satellite navigation signals quicker than terminals only supporting GNSS. Active test is to measure the radiant power and receiving sensitivity of terminal over the air in a microwave anechoic chamber, which displays radiation performance of whole terminal obviously. Many test plans for OTA have been released, and among them the most recognized one is released by CITA. The instruments are mainly provided by Spirent and RS. This paper introduces test plans, test situation of network operators and test institutions, compares 2 solutions provided by Spirit and RS, describes test procedures, and simulates sensitivity test process. © 2021 IEEE.

关键词： Testing

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Simulation analysis on magnetic field of internal linear motor in the micro compressor 5

Simulation analysis on magnetic field of internal linear mot...

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5th IEEE Advanced Information Management, Communicates, Electronic and Automation control Conference, IMCEC 2022

作者： Zhao, Yibo Li, Chenyun Shanghai Institute of Measurement and Testing Technology Shanghai201203 China Shanghai Key Laboratory of Online Test and Control Technology Shanghai201203 China

ISBN: (纸本)9781665479677

In this paper, the magnetic field of internal linear motor in the micro compressor is simulated. Through finite element analysis and calculation of the magnetic flux density within the internal air gap of the micro linear motor under the conditions of different air gap width, air gap thickness, magnetic steel thickness and overall radial size of the motor, it is found that the initial setting size is the best size, which can not only meet the premise that the magnetic induction strength is unchanged, but also ensure uniform magnetic field distribution, The size and quality of the compressor are minimized. On the other hand, this study also verifies the rationality of the scaling principle for miniaturization. © 2022 IEEE.

关键词： linear motors

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Aqueous-phase formation of N-containing secondary organic compounds affected by the ionic strength

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Journal of Environmental Sciences 2024年第4期138卷 88-101页

作者： Yuqi Gan Xiaohui Lu Shaodong Chen Xinghua Jiang Shanye Yang Xiewen Ma Mei Li Fan Yang Yewen Shi Xiaofei Wang Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention Department of Environmental Science and EngineeringFudan UniversityShanghai 200433China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China Guangdong Provincial Observation and Research Station for Coastal Atmosphere and Climate of the Great Bay Area Southern University of Science and TechnologyShenzhen 518055China Institute of Mass Spectrometry and Atmospheric Environment Guangdong Provincial Engineering Research Center for On-line Source Apportionment System of Air PollutionJinan UniversityGuangzhouChina Environmental Monitoring Station of Pudong New District Shanghai 201200China Shanghai Municipal Center for Disease Control&Prevention Shanghai 200336China

The reaction of carbonyl-to-imine/hemiaminal conversion in the atmospheric aqueous phase is a critical pathway to produce the light-absorbing N-containing secondary organic compounds(SOC).The formation mechanism of these compounds has been wildly investigated in bulk solutions with a low ionic ***,the ionic strength in the aqueous phase of the polluted atmosphere may be *** is still unclear whether and to what extent the inorganic ions can affect the SOC *** we prepared the bulk solution with certain ionic strength,in which glyoxal and ammonium were mixed to mimic the aqueous-phase *** characterization by High-resolution Mass Spectrometry was performed to identify the N-containing products,and the light absorption of the mixtures was measured by ultraviolet-visible ***-nine N-containing compounds were identified and divided into four categories(N-heterocyclic chromophores,high-molecular-weight compounds with N-heterocycle,aliphatic imines/hemiaminals,and the unclassified).It was observed that the longer reaction time and higher ionic strength led to the formation of more N-heterocyclic chromophores and the increasing of the lightabsorbance of the *** added inorganic ions were proposed to make the aqueous phase somewhat viscous so that the molecules were prone to undergo consecutive and intramolecular reactions to form the *** general,this study revealed that the enhanced ionic strength and prolonged reaction time had the promotion effect on the lightabsorbing SOC *** implies that the aldehyde-derived aqueous-phase SOC would contribute more light-absorbing particulate matter in the industrial or populated area where inorganic ions are abundant.

关键词： Ionic strength Carbonyl-to-imine/hemiaminal Heterocyclic Brown carbon Mass spectrometry Aqueous-phase reaction

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