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Generation of Atmospheric Pressure Plasma by Repetitive Nanosecond Pulses in Air Using Water Electrodes

Plasma Science and Technology 2011年第6期13卷 735-739页

作者：邵涛于洋章程姜慧严萍周远翔 Institute of Electrical Engineering Chinese Academy of Sciences Key Laboratory of Power Electronics and Electric Drive Chinese Academy of Sciences State Key Laboratory of Control and Simulation of Power Systems and Generating Equipment Electrical Engineering DepartmentTsinghua University

Dielectric barrier discharge （DBD） excitated by pulsed power is a promising method for producing nonthermal plasma at atmospheric pressure. Discharge characteristic in a DBD with salt water as electrodes by a home-made unipolar nanosecond-pulse power source is presented in this paper. The generator is capable of providing repetitive pulses with the voltage up to 30 kV and duration of 70 ns at a 300 Ω resistive load. Applied voltage and discharge current are measured under various experimental conditions. The DBD created between two liquid electrodes shows that the discharge is homogeneous and diffuse in the whole discharge regime, Spectra diagnosis is conducted by an optical emission spectroscopy. The air plasma has strong emission from nitrogen species below 400 nm, notably the nitrogen second positive system.

关键词： non-thermal plasma dielectric barrier discharge pulsed power nanosecondpulse pulse repetition frequency atmospheric pressure air emission spectra.

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Recent advances on smart grid technology and renewable energy integration

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Science China(Technological Sciences) 2013年第12期56卷 3040-3048页

作者： MEI ShengWei CHEN LaiJun State Key Lab of Control and Simulation of Power Systems and Generation Equipments (Dept. of Electrical Engineering Tsinghua University)

With the integration of renewable energy generations and other related changes,the smart grid,or the future electric power system,is confronted with new challenges and ***,it is a promising subject in electrical engineering and much work has been done on *** paper reviews the recent advances on the technologies of smart grid and renewable energy integration,from the aspects of modeling,simulation,protection and control,stability,operation,and planning.

关键词： smart grid renewable energy integration modeling simulation protection and control stability operation planning

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Electrical tree degradation of MgO/epoxy resin composites at different voltage frequencies

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High Voltage 2024年第3期9卷 581-590页

作者： Yunxiao Zhang Wenxin Lin Yuanxiang Zhou Weiwei Xing Jiayu Cheng Chenyuan Teng College of Electrical Engineering and Automation Fuzhou UniversityFujian Key Laboratory of New Energy Generation and Power ConversionFuzhouChina State Key Laboratory of Control and Simulation of Power Systems and Generation Equipment Department of Electrical EngineeringTsinghua UniversityBeijingChina

Electrical tree degradation is one of the main causes of insulation failure in high-frequency *** tree degradation is studied on pure epoxy resin(EP)and MgO/EP composites at frequencies ranging from 50 Hz to 130 *** results show that the tree initiation voltage of EP decreases,while the growth rate and the expansion coefficient increase with ***,the bubble phenomenon at high frequencies in EP composites is *** with trap distribution character-istics within the material,the intrinsic mechanism of epoxy composites to inhibit the growth of the electrical tree at different frequencies is *** can be concluded that more deep traps and blocking effect are introduced by doping nano-MgO into EP bulks,which can improve the electrical tree resistance performance of EP composites in a wide frequency range.

关键词： composites tree Electrical

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Data-driven Transient Stability Assessment Model Considering Network Topology Changes via Mahalanobis Kernel Regression and Ensemble Learning

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Journal of Modern power systems and Clean Energy 2020年第6期8卷 1080-1091页

作者： Xianzhuang Liu Xiaohua Zhang Lei Chen Fei Xu Changyou Feng State Grid Corporation of China State Grid Jibei Electric Power Company the State Key Laboratory of Control and Simulation of Power System and Generation Equipment Department of Electrical EngineeringTsinghua University

Transient stability assessment(TSA)is of great importance in power system operation and *** of the usual tasks in TSA is to estimate the critical clearing time(CCT)of a given fault under the given network topology and pre-fault power ***-driven methods try to obtain models describing the mapping between these factors and the CCT from a large number of ***,the influence of network topology on CCT is hard to be analyzed and is often ignored,which makes the models inaccurate and *** this paper,a novel data-driven TSA model combining Mahalanobis kernel regression and ensemble learning is proposed to deal with the *** model is a weighted sum of several *** sub-model only uses the data of one topology to construct a kernel *** weights are determined by both the topological similarity and numerical similarity between the *** similarities are decided by the parameters in Mahalanobis distance,and the parameters are to be *** reduce the model complexity,sub-models within the same topology category share the same *** estimating CCT,the model uses not only the sub-model which the sample topology belongs to,but also other ***,it avoids the problem that there may be too few data under some *** also efficiently utilizes information of data under all the ***,its decision-making process is clear and understandable,and an effective training algorithm is also *** results on both the IEEE 10-machine 39-bus and a real system verify the effectiveness of the proposed model.

关键词： Transient stability assessment critical clearing time network topology change Mahalanobis kernel regression ensemble learning data-driven

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Development and experimental validation of an automatic parking brake system with less driveline sensor

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Science China(Technological Sciences) 2018年第11期61卷 1628-1641页

作者： WANG JunNian SUN NaNa YAN JiaWei SONG DaFeng WANG QingNian State Key Laboratory of Automotive Simulation and Control Jilin University Chassis Systems Control Division Bosch Automotive Products (Suzhou) Co. Ltd.

Electrical Parking Brake(EPB) has been popularly used in passenger cars over the past ten years. With the help of the several kinds of sensors mounted in driveline for the total traction force estimation, EPB can obtain well performance on drive-off assistance and automatic parking brake. Furthermore, its AUTOHOLD function can realize automatic parking brake and ease the driver. However, given that the higher cost and complexity of this traction force estimation method based on the driveline sensors and its slower response resulted by applying maximum parking force for safety parking while driving off, a novel automatic parking brake system without these transmission system sensors, such as clutch position sensor for the cars with manual transmission, is proposed in this paper, including its control scheme and application test. Firstly, the indirect judgement method of the appropriate moment to release the parking brake, which is based on the car pitch moment when it drives off, is introduced according to the force analysis when the car is ready to go. Then a pragmatic mass estimation method for proper brake force calculation is proposed for improving the drive-off performance. In addition, for the convenience and drivability of skillful driver, as well as the system reliability, a mechanical redundant design to reserve the conventional handbrake lever is also described. Finally, various simulations based on CarSim software and road tests are performed to validate its effectiveness.

关键词： automatic parking brake mass estimation hill-start assist releasing time drive-off tilt angle redundant design

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Passenger cars' zero emission require clean power supply: provincial evidence from NEVs’ indirect emission through 2035

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Journal of Cleaner Production 2025年 507卷

作者： Shi, Xurong Yang, Wenyi Xue, Wenbo Zhang, Zhe Wen, Jie Liu, Xin Yi, Honghong Yan, Gang Cai, Bofeng Wang, Jinnan School of Civil and Resources Engineering University of Science and Technology Beijing Beijing100083 China Center of Environmental Pollution and Greenhouse Gases Co-control Chinese Academy of Environmental Planning Beijing100041 China State Environmental Protection Key Laboratory of Environmental Planning and Policy Simulation Chinese Academy of Environmental Planning Beijing100041 China Center for Carbon Neutrality Chinese Academy of Environmental Planning Beijing100041 China China Electric Power Research Institute Beijing100192 China

China's coal-dominated power structure raises concerns that indirect emissions from electricity generation may offset or even surpass direct emission reduction benefits of new energy vehicles (NEVs). Thus, conducting a life-cycle assessment of NEVs is critical to objectively evaluate these trade-offs. Here, we carried out this assessment for passenger cars, considering NEVs development and power structure transition. Our methodology combines vehicle fleet projection, power grid projection and emission calculation model. Results show that although significant NEVs benefits, by 2035, under baseline power structure, NEVs indirect emission will still account for 31–39% and 17–23% of total emission for CO2 and NOx nationwide. Moreover, it will offset 50% and 18% of use-phase CO2 and NOx reduction, while under clean power structure, these ratios will decrease to ∼32% and 14%. Notably, large discrepancies of NEVs trade-offs exist across 31 provinces. Besides, invisible emission transfer is embedded in electricity transfer: 31% and 69% of NEVs' indirect NOx emissions in Shanxi and Inner Mongolia are projected from NEVs power consumption in other provinces. Therefore, it's urgent to synergistically clean transport and energy sector. © 2025

关键词： Low emission

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Energy saving analysis of segment positioning in shield tunneling machine considering assembling path optimization

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Journal of Central South University 2014年第12期21卷 4526-4536页

作者：施虎龚国芳杨华勇梅雪松 State Key Laboratory for Manufacturing Systems Engineering Xi’an Jiaotong University State Key Laboratory of Fluid Power Transmission and Control Zhejiang University

A motion parameter optimization method based on the objective of minimizing the total energy consumption in segment positioning was proposed for segment erector of shield tunneling machine. The segment positioning process was decomposed into rotation, lifting and sliding actions in deriving the energy calculation model of segment erection. The work of gravity was taken into account in the mathematical modeling of energy consumed by each actuator. In order to investigate the relationship between the work done by the actuator and the path moved along by the segment, the upward and downward directions as well as the operating quadrant of the segment erector were defined. Piecewise nonlinear function of energy was presented, of which the result is determined by closely coupled components as working parameters and some intermediate variables. Finally, the effectiveness of the optimization method was proved by conducting a case study with a segment erector for the tunnel with a diameter of 3 m and drawing comparisons between different assembling paths. The results show that the energy required by assembling a ring of segments along the optimized moving path can be reduced up to 5%. The method proposed in this work definitely provides an effective energy saving solution for shield tunneling machine.

关键词： energy saving segment erector work of gravity path optimization shield tunneling machine

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Significant potential of Solid Oxide Fuel Cell systems for distributed power generation and carbon neutrality

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Frontiers in Energy 2022年第6期16卷 879-882页

作者： Ziyuan TENG Minfang HAN Fuel Cell and Energy Storage Center Department of Energy and Power EngineeringState Key Laboratory of Control and Simulation of Power Systems and Generation EquipmentTsinghua UniversityBeijing 100084China

Energy is important for human survival and *** September 2020,the Chinese government announced that“China aims to have their CO_(2) emissions peak before 2030 and achieve carbon neutrality before 2060.”As China’s reformation and opening-up proceeds into its fifth decade,this new vision for its future is in line with that of the world’s major economies in terms of the need to reach net zero emissions globally by the mid-21stcentury[1].However,coal-fueled thermal power generation is currently dominant and accounts for more than 70%of the total amount of power generated in China,making it the world’s largest energy consumer and carbon *** on the country’s domestic resources,namely the abundance of coal and scarcity of oil and gas,it would be difficult to fundamentally change this coal-based energy structure in the short *** 2021,the global total energy sector was responsible for 36.3 Gt of CO_(2) emissions,including approximately 12 Gt from China,which thus accounts for one-third of the total global emissions[2].The demand for efficiency,energy savings,and emissions reduction in the power generation industry has become increasingly *** need has arisen to enhance ways in which to use coal cleanly and efficiently,reduce the consumption thereof,and replace coal with other forms of *** addition,carbon emissions need to be lowered by promoting the adoption of alternative power generation technologies that are more energy *** would require transformation away from coal power and the exploration of clean,efficient,flexible,and safe forms of energy as the main future development directions[3].

关键词： neutral carbon replace

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Collision efficiency of two nanoparticles with different diameters in Brownian coagulation

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Applied Mathematics and Mechanics(English Edition) 2011年第8期32卷 1019-1028页

作者：王玉明林建忠 Institute of Fluid Measurement and Simulation China Jiliang University State Key Laboratory of Fluid Power Transmission and Control Zhejiang University

The collision efficiency of two nanoparticles with different diameters in the Brownian coagulation is investigated. The collision equations are solved to obtain the collision efficiency for the dioctyl phthalate nanoparticle with the diameter changing from 100 nm to 750 nm in the presence of the van der Waals force and the elastic deformation force. It is found that the collision efficiency decreases as a whole with the increase of both the particle diameter and the radius ratio of two particles. There exists an abrupt increase in the collision efficiency when the particle diameter is equal to 550 nm. Finally, a new expression is presented for the collision efficiency of two nanoparticles with different diameters.

关键词： nanoparticle Brownian coagulation collision efficiency different diameters van der Waals force elastic force

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Study on static and dynamic characteristics of the electro-hydraulic proportional directional valve

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Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 2025年

作者： Yang, Meisheng Kun, Lian Shuang, Luo Jiahan, Bao Huaizhi, Zong Anhui Province Engineering Laboratory of Intelligent Demolition Equipment Anhui University of Technology Maanshan China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang University Hangzhou China Anhui Key Laboratory of Mine Intelligent Equipment and Technology Anhui University of Science and Technology Huainan China Anhui Province Key Laboratory of Advanced Numerical Control & Servo Technology AnHui Polytechnic University Wuhu China Engineering Technology Research Center of Hydraulic Vibration Technology Anhui University of Technology Maanshan China

Electro-hydraulic proportional directional valves are widely used in precision engineering fields, where their operational stability and reliability are critical to the performance of hydraulic systems. However, high pressure and high-frequency responses significantly affect the hydraulic forces acting on the spool, while deformations caused by pressure and thermal loads may further compromise its performance. Therefore, analyzing and compensating for hydraulic forces, as well as investigating the deformation behavior of the spool under pressure and thermal loads, are essential for enhancing its stability and reliability. Based on CFD numerical calculation methods and fluid-thermal-solid multi-physics coupling technology, the study systematically investigates the characteristics of hydraulic forces and the deformation behavior of the spool. First, Fluent was used to simulate the fluid domain under steady-state and transient conditions, obtaining pressure and velocity contour maps, flow rate curves, and the hydraulic forces acting on the spool in different structural cavities formed by the valve sleeve and spool at different valve opening degrees. The analysis identified the best cavity configuration for compensating hydraulic forces between the valve sleeve and spool. Secondly, orthogonal experimental design and numerical simulation were conducted for the arc-shaped transition cavity, followed by multi-objective optimization using a genetic algorithm. The optimized structure reduced the steady-state hydraulic force to varying extents, with a maximum reduction of 23%. Finally, the fluid-thermal-solid multi-physics coupling technology was employed, selecting the optimal structure with the best hydraulic force compensation effect for analysis. The results show that the deformation of the spool in both radial directions increase as the valve opening increases. At a valve opening of 1 mm, the maximum radial deformation in the Z direction is 7.0471 μm. Additionally, with

关键词： deformation Directional valve hydraulic forces mass flow rate optimization

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