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11th Frontier Academic Forum of Electrical Engineering, FAFEE 2024

作者： Ma, Pengyu Li, Benliang Zou, Jun State Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua University Beijing100084 China State Power Economic Research Institute Beijing102200 China

ISBN: (纸本)9789819787791

With the development of cities, underground tunnels are more and more widely used, and the reinforced concrete in their walls can be used as the natural grounding body of the tunnels. However, underground tunnels have curved structures, multiple cross-sections and deep-buried structures, and the electrical conductivity of the concrete is different from that of the soil, etc., and the traditional analytical method has limitations in calculating the grounding resistance of the tunnels in these cases. In order to satisfy the needs of practical engineering, this paper adopts a numerical method based on the MoM numerical method to analyze the grounding system of underground tunnels with complex geometries and to calculate the grounding resistance of reinforced concrete systems in underground tunnels. In order to assess the difference between the analytical solution and the exact solution, the article introduces a correction factor to measure the ratio between the two. simulations are carried out for real cases, and the results show that the accuracy of the analytical solution can be improved by introducing the correction factor. © Beijing Paike Culture Commu. Co., Ltd. 2025.

关键词： correction factor grounding resistance numerical method Underground tunnels

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Polyethylene microplastics hamper aged biochar’s potential in mitigating greenhouse gas emissions

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Carbon Research 2025年第1期4卷 1-14页

作者： Chen, Yalan Wang, Zhibo Zhang, Anqi Li, Yang Sun, Ke Jiang, Chenrun Gunina, Anna Aloufi, Abeer S. Liang, Xinru Han, Zichen Xiao, Yue Zhang, Yunqian Du, Zhangliu Zhu, Shishu Kuzyakov, Yakov State Key Laboratory of Water Environment Simulation School of Environment Beijing Normal University Beijing100875 China College of Life Sciences Beijing Normal University Beijing100875 China Department of Urban Engineering Graduate School of Engineering The University of Tokyo Tokyo113-8656 Japan Agrarian and Technological Institute RUDN University Miklukho-Maklaya st. 6 Moscow117198 Russia Department of Biology College of Science Princess Nourah Bint Abdulrahman University P.O. Box 84428 Riyadh11671 Saudi Arabia Beijing Key Laboratory of Biodiversity and Organic Farming College of Resources and Environmental Sciences China Agricultural University Beijing100193 China The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters Ministry of Education School of Environment and Energy South China University of Technology Guangzhou510006 China Department of Soil Science of Temperate Ecosystems Department of Agricultural Soil Science University of Goettingen Göttingen37077 Germany Moscow117198 Russia

While biochar effectively reduces greenhouse gas emissions, the coincident microplastics will alter these benefits. To assess the long-term efficacy of biochar application in reducing emissions amidst microplastic interference, we investigated the interactive effects of polyethylene microplastics (1%–5% wt) and decadal biochar addition (aged biochar) on C and N stability in a Fluvic Cambisol. Aged biochar and polyethylene individually reduced CO2 emissions by 49% and 18%, respectively, over 91-day incubation. This was due to decreased soil aggregation, dissolved organic matter (DOM) content, and increased DOM aromaticity, which reduced microbial biomass and chitinase activity associated with soil organic matter (SOM) decomposition. This ultimately led to increased accumulation of microbial necromass carbon (MNC) to soil stable carbon pool. Interestingly, the coexistence of polyethylene diminished the efficacy of biochar in mitigating CO2 emissions (+ 44 ~ 82%) and stabilizing MNC (-18 ~ 23%). This was because the interaction between polyethylene and biochar facilitated macroaggregate formation and DOM accumulation and decreased DOM aromaticity, which increased microbial biomass and chitinase activity for SOM decomposition. Similar to soil C dynamics, aged biochar largely reduced N2O emissions by 54%, due to decreased nirK but increased nifH genes. Polyethylene increased N2O emissions by 5% and 25% in biochar-free and aged biochar soil, respectively, likely through upregulation of nirS and nirK but downregulating nifH gene expression. Thus, polyethylene microplastics may undermine the benefits of biochar in mitigating climate change, highlighting the necessity to recognize microplastics as a global change factor and to incorporate their role in elemental cycling alongside their global transport. Graphic Abstract: (Figure presented.) © The Author(s) 2025.

关键词： Greenhouse gas emissions

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Linear Precoding Design for MIMO-PLC Systems

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Tsinghua Science and Technology 2015年第2期20卷 155-163页

作者： Jisheng Peng the State Key Lab of Control and Simulation of Power Systems and Generation Equipment Department of Electrical Engineering Tsinghua Uinversity

In this paper, we consider the design of linear precoding in Multiple Input Multiple Output （MIMO） Power Line Communication （PLC） systems with finite-alphabet input. First, we derive mutual information of MIMO-PLC systems with impulsive noise. Considering the non-concavity of the objective function and the low-cost requirement of PLC systems, we choose the lower bound of the mutual information as the objective function. Subsequently, we propose a novel approach to design the precoding scheme to reduce computational complexity. Specifically, our work primarily includes the following two contributions：（1） We design the right unitary matrix that is a product of two fixed unitary matrices, which only depends on the modulation mode. Hence, the results can be saved and require less computations. （2） For the power allocation matrix, we first reduce the space of power allocation using constraints of the optimal power allocation policy. Consequently, we propose a non-linear search method to obtain the optimal power allocation in small space. In regards to the computational complexity of the analysis, we conclude that the proposed precoding matrix design scheme has low complexity and is easy to implement. Moreover, the numerical results are proven to demonstrate the performance of the proposed precoding design scheme.

关键词： precoding design MIMO-PLC impulsive noise finite-alphabet input

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Climatic features of wind field and their impact on local air quality in Taiyuan Basin

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Science of the Total Environment 2025年 979卷

作者： Liu, Shutong Cai, Xuhui Song, Yu Zhang, Hongsheng Yan, Yan Wang, Xiaobin State Key Lab of Environmental Simulation and Pollution Control College of Environmental Sciences and Engineering Peking University Beijing100871 China Department of Atmospheric and Oceanic Sciences School of Physics Peking University Beijing100871 China Laboratory for Climate Studies National Climate Center China Meteorological Administration Beijing100081 China Weather Modification Centre China Meteorological Administration Beijing100081 China

Taiyuan Basin has long been considered as one of the most air-polluted regions in China, closely related to its enclosed terrain and local climatic conditions. In this study, the wintertime climatic characteristics of the wind field and the corresponding boundary layer structure were investigated for their potential impact on local air quality in Taiyuan Basin, utilizing long-term Weather Research and Forecasting model simulations from 2015 to 2020. Prevailing southwesterly wind in this basin was revealed. It was demonstrated that the blocking effect of the mountains to the dominant airflow of winter monsoon, and the guidance of the basin orientation to the diverted wind, lead to this fundamental feature. Eight synoptic patterns were identified based on the obliquely rotated T-mode Principal Component Analysis (T-PCA) and further grouped into pollution-prone and relatively clean pattern types. Weak winds, low boundary layer height, higher temperature and higher relative humidity were associated with pollution-prone synoptic patterns, while the opposite conditions were related to the clean patterns. Lower and higher ventilation indexes (2 s−1 and > 4000 m2 s−1) were also distinct the former from the latter patterns. Two case studies revealed the detailed vertical structure of boundary layer wind and temperature, as well as their temporal variation during the pollution episode. The influence of upper layer southwest warm advection was emphasized. In contrast, for clean events in this basin, the removal of air pollutants heavily depended on the air-flushing process brought by the stronger weather system, which occurred in frequency approximately 36 % in the winter season. © 2025

关键词： Air quality

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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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Diesel Engine SCR control: Current Development and Future Challenges

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Emission control Science and Technology 2015年第2期1卷 121-133页

作者： Yuan, Xinmei Liu, Hongqi Gao, Ying State Key Lab. of Automotive Simulation and Control Jilin University ChangchunJilin130025 China

To meet increasingly stringent emission legislations, selective catalytic reduction (SCR) becomes an essential aftertreatment technique. This paper presents a comprehensive overview of the current development and future challenges of SCR control technologies. In this paper, SCR system hardware configurations are introduced, modeling and calibration of the SCR converter are provided, and current control strategies are summarized and reviewed. Finally, primary areas driving the future of SCR control research are discussed. © 2015, Springer SIP, AG.

关键词： Selective catalytic reduction

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Simplified mathematical model of inter-turn short circuit of field windings in hydro-generators and its application

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Science China(Technological Sciences) 2013年第4期56卷 898-909页

作者： HAO LiangLiang WU JunYong SUN YuGuang WANG XiangHeng School of Electrical Engineering Beijing Jiaotong University State Key Lab of Control and Simulation of Power Systems and Generation Equipment Tsinghua University

Inter-turn short circuit of field windings is a common electrical fault of *** is an important method of investigating the fault and providing data support for fault ***,huge numbers of pole pairs and damper loops in large hydro-generators would lead to lengthy calculation time,hindering scientific research and engineering *** deal with this problem,we analyze a theoretical basis for a damper winding simplified model and then propose an equivalent treatment *** the analysis of steady-state current harmonic characteristics of generators with different stator winding configurations during the fault,the simplified models suitable for steady-state calculation are derived from two aspects,namely,additional rotor harmonic current frequency characteristics and the relationship of the amplitude as well as the phase of each branch current of the *** calculation and experimental results of the two simplified models are then compared to verify the models' correctness.A calculation example of the Three Gorges left bank VGS generator shows few deviations between the calculation results of the simplified model and the original ***,the calculation time using the simplified model is 1/1500 that using the original model,which provides a more effective tool for on-line fault ***,the sensitivity-verification application of the fault-monitoring scheme based on the stator steady-state unbalanced current RMS is *** result shows that the scheme can monitor two-turn short circuits of field windings in the Three Gorges generator and provide high sensitivity.

关键词： hydro-generator field windings inter-turn short circuit simplified model on-line monitoring

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Investigation on the Mechanical Properties and Shape Memory Effect of Landing Buffer Structure Based on Ni Ti Alloy Printing

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Chinese Journal of Mechanical Engineering 2023年第4期36卷 415-424页

作者： Zhenglei Yu Renlong Xin Zezhou Xu Yining Zhu Xiaolong Zhang Shijie Hao Zhihui Zhang Ping Liang State Key Laboratory of Automotive Simulation and Control Jilin University Key Lab of Bionic Engineering Ministry of Education Jilin University Agriculture College Yanbian University State Key Laboratory of Heavy Oil Processing China University of Petroleum

With the deepening of human research on deep space exploration, our research on the soft landing methods of landers has gradually deepened. Adding a buffer and energy-absorbing structure to the leg structure of the lander has become an effective design solution. Based on the energy-absorbing structure of the leg of the interstellar lander, this paper studies the appearance characteristics of the predatory feet of the Odontodactylus scyllarus. The predatory feet of the Odontodactylus scyllarus can not only hit the prey highly when preying, but also can easily withstand the huge counter-impact force. The predatory feet structure of the Odontodactylus scyllarus, like a symmetrical cone, shows excellent rigidity and energy absorption capacity. Inspired by this discovery, we used SLM technology to design and manufacture two nickel-titanium samples, which respectively show high elasticity, shape memory, and get better energy absorption capacity. This research provides an effective way to design and manufacture highmechanical energy-absorbing buffer structures using bionic 3D printing technology and nickel-titanium alloys.

关键词： Bionic protective structure Odontodactylus scyllarus NiTi alloy 3D printing Numerical simulation Recoverability

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Industrial Application of a Deep Purification Technology for Flue Gas Involving Phase-Transition Agglomeration and Dehumidification

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Engineering 2018年第3期4卷 416-420页

作者： Jianmin Liu Fahua Zhu Xiuyuan Ma State Power Environmental Protection Research Institute State Environmental Protection Key Lab for Air Physical Simulation & Pollution Control Nanjing 210031 China

A moist plume forms when the flue gas emitted from wet desulfurization equipment exits into the ambi- ent air, resulting in a waste of water resources and visual pollution. In addition, sulfur trioxide （SO3）, water with dissolved salts, and particles in the wet flue gas form secondary pollution in the surrounding atmosphere. In this study, a deep purification technology for flue gas involving phase-transition agglom- eration and dehumidification （PAD） is proposed. This deep purification technology includes two technical routes： the integrated technology of phase-transition agglomeration and a wet electrostatic precipitator （PAW）; and the integrated technology of phase-transition agglomeration and a mist eliminator （PAM）. Industrial applications of PAW and PAM were carried out on 630 and 1000 MW coal-fired units, respectively. The results show that the average amount of recycled water obtained from wet flue gas by means of PAD is more than 4 g.（kg.℃）-1 Decreasing the wet flue gas temperature by 1.5-5.3 ℃ allows 5%-20% of the moisture in the flue gas to be recycled; therefore, this process could effectively save water resources and significantly reduce water vapor emissions. In addition, the moist plume is effectively elim- inated. With the use of this process, the ion concentration in droplets of flue gas is decreased by more than 65%, the SO3 removal efficiency from flue gas is greater than 75%, and the removal efficiency of par- ticulate matter is 92.53%.

关键词： Moist plume Phase-transition agglomeration Dehumidification Dissolved salts SO3 Particulate matter

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Vehicle cycle analysis comparison of battery electric vehicle and conventional vehicle in china

Vehicle cycle analysis comparison of battery electric vehicl...

引用

SAE/KSAE 2013 International Powertrains, Fuels and Lubricants Meeting, FFL 2013

作者： Li, Shuhua Li, Jun Li, Nannan Gao, Ying State Key Lab of Automotive Simulation and Control Jilin Univ China

The encouragement for the development of battery electric vehicles (BEVs) has increased in China, especially after the automotive industry planning in 2009. In general, BEVs are associated with a cleaner and more efficient mobility during operation;however the benefits of substituting BEVs for internal combustion engine vehicles (ICEVs) must be evaluated. Vehicle cycle analyses are important tools that provide a comprehensive approach to compare the environmental effects of advanced and conventional vehicles. The goal of this study is to estimate and compare the vehicle cycle energy and emission impacts of a mid-size passenger BEV with a mid-size passenger ICEV in China. It is found that the material production accounts for the majority of the vehicle cycle energy consumption and emissions for the two vehicle types. Comparing the vehicle cycle of the BEV and ICEV, the energy consumption of BEV is 40.0% higher than that of ICEV and the total greenhouse gas (GHG) emissions of BEV is 44.6% higher than that of ICEV, due to the use of energy-intensive materials in the power battery of BEV. Meanwhile, the fuel cycle analyses are used in conjunction with the vehicle cycle analyses to estimate the full automobile lifecycle results. It is found that in the terms of the full life cycle of the ICEV and BEV, the overall energy use of the BEV is 26.6% lower than that of ICEV and the overall GHG emissions of BEV is 12.8% lower than that of ICEV. Copyright © 2013 SAE International and Copyright © 2013 KSAE.

关键词： Energy utilization

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