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15th IEEE International Conference on Mechatronics and Automation, ICMA 2018

作者： Chen, Zhihua Xie, Yongchun Beijing Institute of Control Engineering China Science and Technology on Space Intelligent Control Laboratory Beijing China Tianjin Key Laboratory of Microgravity and Hypogravity Environment Simulation Technology Tianjin China

ISBN: (纸本)9781538660720

Under the perspective of numerical computation, this paper investigates the finite-time stability (FTS) of continuous linear time-varying (LTV) systems when all its initial values are confined within a given polyhedral set while all its states are confined within a given ellipsoidal set. First, by solving a certain function optimization problem, the paper proposes a necessary and sufficient condition to guarantee the FTS of continuous LTV systems. Then, by utilizing the Lipschitz continuity of a certain function, two sufficient conditions to verify the FTS and finite-time instability of continuous LTV systems are proposed under the perspective of numerical computation, respectively. Furthermore, a novel numerical algorithm for analyzing the FTS of continuous LTV systems is deigned by converting a certain function optimization problem into a corresponding quadratic programming. Finally, a numerical example is given to illustrate the effectiveness of the proposed algorithm. © 2018 IEEE.

关键词： Quadratic programming

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Flow Separation and Vortex Dynamics in Waves Propagating over A Submerged Quartercircular Breakwater

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China Ocean Engineering 2018年第5期32卷 514-523页

作者： JIANG Xue-lian YANG Tian ZOU Qing-ping GU Han-bin Tianjin Key Laboratory of Soft Soil Characteristics & Engineering Environment Tianjin Chengjian University State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin University The Lyell Centre for Earth and Marine Science and Technology Institute for Infrastructure and EnvironmentHeriot-Watt University School of Naval Architecture &Mechanical-Electrical Engineering Zhejiang Ocean University

The interactions of cnoidal waves with a submerged quartercircular breakwater are investigated by a ReynoldsAveraged Navier–Stokes(RANS) flow solver with a Volume of Fluid(VOF) surface capturing scheme(RANSVOF) model. The vertical variation of the instantaneous velocity indicates that flow separation occurs at the boundary layer near the breakwater. The temporal evolution of the velocity and vorticity fields demonstrates vortex generation and shedding around the submerged quartercircular breakwater due to the flow separation. An empirical relationship between the vortex intensity and a few hydrodynamic parameters is proposed based on parametric analysis. In addition, the instantaneous and time-averaged vorticity fields reveal a pair of vortices of opposite signs at the breakwater which are expected to have significant effect on sediment entrainment, suspension, and transportation,therefore, scour on the leeside of the breakwater.

关键词： submerged quartercircular breakwater cnoidal wave flow separation vortex dynamics scour

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How vehicle and fuel specifications affect evaporative and refuelling emissions from petrol vehicles

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Journal of environmental Sciences 2025年

作者： Chunxiao Hao Yunshan Ge Xin Wang Jindong Liang Peng Chen Hong Bao Jiachen Li Dailin Yin Chongyao Wang Ruonan Li Junfang Wang Jia Ke Qing Liu Hang Yin National Laboratory of Automotive Performance & Emission Test School of Mechanical Engineering Beijing Institute of Technology Beijing 100081 China Key Laboratory for Vehicle Emission Control and Simulation of Ministry of Ecology and Environment Chinese Research Academy of Environmental Sciences Beijing 100012 China Beijing Smart Green Transport Research Centre Beijing 100022 China Pan Asia Technical Automotive Centre Co. Ltd. Shanghai 201206 China CATARC Automotive Test Centre Tianjin Co. Ltd. Tianjin 300300 China

Evaporative and refuelling emissions are a major source of volatile organic compound (VOC) contamination, contributing to ground-level ozone formation in China. To meet increasingly stringent evaporative emission control requirements, a growing number of newly certified vehicles have adopted onboard refuelling vapour recovery systems and updated canisters. This study aimed to evaluate the impact of vehicle and fuel specifications on evaporative and refuelling emissions from China-6 light-duty vehicles (LDVs). Two groups of experiments were conducted. In the first group, 28 tests were performed on China-6 LDVs and 24 on China-5 LDVs. The results showed that emissions from China-6 LDVs were significantly lower than those from China-5 LDVs in terms of total hydrocarbon emissions and diurnal losses over 0-24 h, with lower variability. In the second group, seven petrol fuel samples with varying aromatic formulations, ethanol contents, and vapour pressures were tested. Evaporative emissions and refuelling emissions were measured following China-6 procedures, while speciated VOCs were also quantified. The results showed that higher molecular weight aromatics more effectively suppressed evaporative emissions than toluene. Both E5 and E10 fuels increased vapour leakage during the diurnal-loss stage. Diurnal loss and refuelling emissions increased significantly with rising fuel Reid vapor pressure, particularly after the canister breakthrough on the second day. Speciated VOC analysis revealed that light alkanes dominated the escaped fuel vapour.

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Vegetation Rather than Climate Dominate the Bowen Ratio Over Terrestrial Ecosystems of China

SSRN

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SSRN 2023年

作者： Sun, Mingyu Yu, Guirui Chen, Zhi Zhu, Xianjin Zhang, Weikang Han, Lang Liu, Zhaogang Ma, Lexin Dou, Xiaojun Yao, Yuan Wang, Jilong Luo, Wenxing Lin, Yong Chen, Shiping Deng, Zhengmiao Dong, Gang Du, Hu Gao, Yanhong Gu, Fengxue Hao, Xiangxiang Hao, Yanbin He, Qihua He, Yongtao He, Jinsheng Ji, Xibin Jiang, Shicheng Jiang, Zhengde Li, Xinhu Li, Yingnian Li, Yuqiang Li, Yuzhe Liu, Ran Liu, Shaomin Luo, Weijun Mo, Xingguo Sha, Liqing Shi, Peili Song, Qinghai Sun, Dan Tan, Junlei Tang, Yakun Wang, Fei Wang, Huimin Wang, Jianlin Wei, Wenxue Wu, Jiabing Wu, Zhixiang Xin, Xiaoping Yan, Junhua Zhang, Fawei Zhang, Yangjian Zhang, Yiping Zhang, Yucui Zhao, Fenghua Zhao, Liang Zhou, Li Zhu, Jiaojun Zhu, Zhilin Institute of Surface-Earth System Science School of Earth System Science Tianjin University Tianjin300072 China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing100101 China College of Resources and Environment University of Chinese Academy of Sciences Beijing100049 China Beijing Yanshan Earth Critical Zone National Research Station University of Chinese Academy of Sciences Beijing101408 China College of Agronomy Shenyang Agricultural University Shenyang100161 China Tianjin Bohai Rim Coastal Earth Critical Zone National Observation and Research Station Tianjin University Tianjin300072 China State Key Laboratory of Vegetation and Environmental Change Institute of Botany Chinese Academy of Sciences Beijing100093 China Key Laboratory for Agro-ecological Processes in Subtropical Region Institute of Subtropical Agriculture Chinese Academy of Sciences Changsha410125 China Shanxi University Taiyuan030006 China Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences Lanzhou730000 China Institute of Environment and Sustainable Development in Agriculture Chinese Academy of Agricultural Sciences Beijing100081 China Center for Agricultural Technology Northeast Institute of Geography and Agroecology Chinese Academy of Sciences Harbin150081 China University of Chinese Academy of Sciences Beijing100049 China Chengdu Institute of Biology Chinese Academy of Sciences Chengdu610041 China Institute of Ecology College of Urban and Environmental Sciences Key Laboratory for Earth Surface Processes the Ministry of Education Peking University Beijing100871 China State Key Laboratory of Herbage Improvement and Grassland Agro-Ecosystems College of Pastoral Agriculture Science and Technology Lanzhou University Lanzhou China School of Life Sciences Northeast Normal University Changchun130024 China Institute of Applied Ecology Chinese

Bowen ratio (β) is the ratio of sensible heat (H) to latent heat (LE), which reflected the energy balance and partitioning process between soil, vegetation, and atmosphere. Revealing the spatial patterns of β would benefit understanding the variation of energy partitioning in terrestrial ecosystems and its reciprocal relationship with environmental change. Here, we calculated β by integrating sensible and latent heat flux values from 80 flux observation sites based on eddy covariance method in ChinaFLUX to analyze the spatial pattern and dominant factors of β in China. Results showed that terrestrial ecosystems in China had an average β of 0.64±0.47, suggesting the strong regulating effect of ecosystems on the radiative warming in China. β significantly varied with ecosystem types in which desert has the highest β (2.08) while wetland showed the lowest β (0.37). β of terrestrial ecosystems in China showed a significant latitudinal pattern, increasing linearly with the increase of latitude, and showed specific patterns in forest and cropland ecosystems. However, β did not present a clear longitudinal and vertical pattern in different ecosystems except cropland. The spatial pattern of β was dominated by vegetation factors including gross primary productivity (GPP). However, the dominant role of vegetation factors varied with the climate and soil conditions, which showing that the dominant role of GPP gradually decreased from the hot and humid subtropical evergreen broad-leaved forest region to the low temperature arid temperate desert region. These findings demonstrated the spatial variation and its mechanism of terrestrial ecosystems β and provided insight into the future of vegetation mitigation of global climate change. © 2023, The Authors. All rights reserved.

关键词： Heat flux

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Alloying effect-induced electron polarization drives nitrate reduction to ammonia

Research Square

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Research Square 2020年

作者： Yin, Haibo Peng, Yue Xiong, Shangchao Chen, Jianjun Wang, Chizhong Wang, Rong Chen, Zhen Kuwahara, Yasutaka Luo, Jingshan Yamashita, Hiromi Li, Junhua State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing100084 China Division of Materials and Manufacturing Science Graduate School of Engineering Osaka University Osaka565-0871 Japan Institute of Photoelectronic Thin Film Devices and Technology Solar Energy Research Center Key Laboratory of Photoelectronic Thin Film Devices and Technology of Tianjin Ministry of Education Engineering Research Center of Thin Film Photoelectronic Technology Nankai University Tianjin300350 China

Electrocatalytic conversion of nitrate (NO3-) to ammonia (NH3) holds significant potential in the control of nitrogen oxide (NOx) from stationary sources. However, previous studies on reaction intermediates remain unclear. Here we report that Pd/Cu2O hybrids with mesoporous hollow sphere structure show high selectivity (96.70%) and Faradaic efficiency (94.32%) for NH3 synthesis from NO3-. Detailed characterizations demonstrate that (1) Pd enables electrons transfer (Pd 3d → Cu 3d) and makes the polarization of Cu 3d orbitals by forming partial PdCu alloys, which makes Pd electron-deficiency but offers empty orbits to adsorb NO3-;(2) electron-rich Cu are more conducive to the occurrence of NO3- reduction. The mutual confirmation of online differential electrochemical mass spectrometry and density functional theory calculations demonstrates that PdCu alloys block the generation of *NOH intermediate and facilitate the formation of *N, finally leading to a higher catalytic performance. © 2020, CC BY.

关键词： Ammonia

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Spin-state Conversion by Asymmetrical Orbital Hybridization in Ni-doped Co3O4to Boost Singlet Oxygen Generation for Microbial Disinfection

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Angewandte Chemie 2024年第12期136卷

作者： Meilin Duan Chao Huang Gong Zhang Hao Shi Pengfei Zhang Limin Li Tong Xu Zhen Zhao Zhujun Fu Jingrui Han Yuanhong Xu Xiaoteng Ding Institute of Biomedical Engineering College of Life Sciences Qingdao University Qingdao 266071 P.R. China Institute of Biomedical Engineering College of Medicine Southwest Jiaotong University Chengdu 610031 Sichuan China Center for Water and Ecology State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 China Department of Urology The Affiliated Hospital of Qingdao University Qingdao 266071 P.R. China Key Laboratory of Marine Chemistry Theory and Technology Ministry of Education Ocean University of China Qingdao 266100 P.R. China School of Materials Science and Engineering Tianjin University Tianjin 300350 P.R. China

Singlet oxygen ( 1 O 2 ) plays a significant role in environmental and biomedical disinfection fields. Electrocatalytic processes hold great potential for 1 O 2 generation, but remain challenging. Herein, a facile Ni doping converted spin-state transition approach is reported for boosting 1 O 2 production. Magnetic analysis and theoretical calculations reveal that Ni occupied at the octahedral site of Co 3 O 4 can effectively induce a low-to-high spin-state transition. The high-spin Ni−Co 3 O 4 generate appropriate binding strength and enhance electron transfer between the Co centers with oxygen intermediates, thereby improving the catalytic activity of Ni−Co 3 O 4 for effective generating 1 O 2 . In neutral conditions, 1×10 6 CFU mL −1 Gram-negative ESBL-producing Escherichia coli ( E. coli ) could be inactivated by Ni−Co 3 O 4 system within 5 min. Further antibacterial mechanisms indicate that 1 O 2 can lead to cell membrane damage and DNA degradation so as to irreversible cell death. Additionally, the developed Ni−Co 3 O 4 system can effectively inactivate bacteria from wastewater and bioaerosols. This work provides an effective strategy for designing high-spin electrocatalysis to boost 1 O 2 generation for disinfection process.

关键词： singlet oxygen spin-related orbital interaction entropy advanced oxidation processes microbial disinfection ROS regulation

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Semi-physical simulation experiment on the on-orbit capture of tumbling uncooperative target spacecraft 69

Semi-physical simulation experiment on the on-orbit capture ...

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69th International Astronautical Congress: #InvolvingEveryone, IAC 2018

作者： Xie, Yongchun Wang, Yunpeng Yang, Baohua Beijing Institute of Control Engineering Beijing100190 China Science and Technology on Space Intelligent Control Laboratory Beijing China Tianjin Key Laboratory of Microgravity and Hypogravity Environment Simulation Technology Tianjin100190 China China Aerospace Science and Technology Corporation Beijing China

A semi-physical simulation experiment is introduced in this paper. The experiment simulates the on-orbit capture of tumbling uncooperative target satellite. The chaser spacecraft (or service spacecraft) is a satellite equipped with a 7 degree of freedom (DOF) manipulator and a relative pose measure sensor. A capture tool is installed at the end of the manipulator. It can capture the nozzle of the target. The relative posse measure sensor can measure the relative position and attitude between the chaser and target spacecrafts. The experiment is carried out on a novel semi-physical simulation system, whose core equipment is a novel 9 DOF motion simulator platform. One main feature of this simulator is that it can simulate the tumbling motion of the satellite. Copyright © 2018 by the International Astronautical Federation (IAF). All rights reserved.

关键词： Manipulators

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Near-real-time global gridded daily CO2 emissions 2021

arXiv

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arXiv 2022年

作者： Dou, Xinyu Hong, Jinpyo Ciais, Philippe Chevallier, Frédéric Yan, Feifan Yu, Ying Hu, Yifan Huo, Da Sun, Yun Wang, Yilong Davis, Steven J. Crippa, Monica Janssens-Maenhout, Greet Guizzardi, Diego Solazzo, Efisio Lin, Xiaojuan Song, Xuanren Zhu, Biqing Cui, Duo Ke, Piyu Wang, Hengqi Zhou, Wenwen Huang, Xia Deng, Zhu Liu, Zhu Department of Earth System Science Tsinghua University Beijing100084 China Department of Computer Science and Technology Tsinghua University Beijing100084 China Laboratoire des Sciences du Climat et de l'Environnement LSCE/IPSL CEA-CNRS-UVSQ UniversitéParis-Saclay Gif-sur-Yvette France Key Laboratory of Marine Environment and Ecology Frontiers Science Center for Deep Ocean Multispheres and Earth System Ministry of Education Ocean University of China Qingdao266100 China Environmental Sciences and Engineering University of North Carolina at Chapel Hill Chapel Hill United States Key Laboratory of Sustainable Forest Ecosystem Management Northeast Forestry University Harbin150040 China School of Environmental Science and Engineering Tianjin University Tianjin300072 China Key Laboratory of Land Surface Pattern and Simulation Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing100101 China Department of Earth System Science University of California IrvineCA United States Ispra Italy Product and Solution & Website Business Unit Alibaba Cloud Hangzhou311121 China

We present a near-real-time global gridded daily CO2 emissions dataset (GRACED) throughout 2021. GRACED provides gridded CO2 emissions at a 0.1°×0.1°spatial resolution and 1-day temporal resolution from cement production and fossil fuel combustion over seven sectors, including industry, power, residential consumption, ground transportation, international aviation, domestic aviation, and international shipping. GRACED is prepared from a near-real-time daily national CO2 emissions estimates (Carbon Monitor), multi-source spatial activity data emissions and satellite NO2 data for time variations of those spatial activity data. GRACED provides the most timely overview of emissions distribution changes, which enables more accurate and timely identification of when and where fossil CO2 emissions have rebounded and decreased. Uncertainty analysis of GRACED gives a grid-level two-sigma uncertainty of value of ±19.9% in 2021, indicating the reliability of GRACED was not sacrificed for the sake of higher spatiotemporal resolution that GRACED provides. Continuing to update GRACED in a timely manner could help policymakers monitor energy and climate policies’ effectiveness and make adjustments quickly. © 2022, CC BY.

关键词： Uncertainty analysis

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Exploring the economically sustainable solutions for clean heating in rural Northern China

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Fundamental Research 2024年

作者： Feng Wang Yuzhu Shang Pengfei Zhang Wei Zhang Jiashuo Li School of Business Institute of Climate Economy and Low-carbon Industry Nanjing University of Information Science & Technology Nanjing 210044 China Institute of Blue and Green Development Shandong University Weihai 264209 China The Center for Beijing-Tianjin-Hebei Regional Environment and Ecology Chinese Academy of Environmental Planning Beijing 100041 China State Environmental Protection Key Laboratory of Environmental Planning and Policy Simulation Chinese Academy of Environmental Planning Beijing 100041 China

China's Rural Clean Heating Policy (RCHP) is confronted with affordability issues in terms of the increasing household heating costs against the background of subsidies phase out, calling for economically feasible strategies to alleviate the heating burden. By compiling a high-resolution township-level RCHP retrofitting dataset, here we comprehensively assessed the rural residential heating burdens, with or without operational subsidies, and further explored the economically viable clean heating strategies in Northern China. We show that eliminating subsidies would significantly increase rural residential heating expenditure by 36.2% (an average of 523.3 CNY per household), and low-income rural residents in Shandong and Shanxi would bear the most significant increase in heating burdens. The incremental costs of heating can be partly offset (18.7%) by RCHP's carbon reduction in the context of the Chinese Certified Emission Reduction. Rural rooftop photovoltaics show significant potential in increasing household revenue, particularly in Hebei, Shanxi, and Beijing, where they can compensate for an average of 32.2–64.5% of the increased heating costs. The implementation of tailored subsidy phase-out strategies, coupled with the promotion of distributed PV projects, could enhance the sustainability of clean heating in China.

关键词： Clean heating residential heating burden clean heating subsidy policies CCER distributed photovoltaics

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Research and Application of Prediction Model for Ecological Balanced Optimal Fertilization Amount for Three Crops

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Meteorological and environmental Research 2020年第5期11卷 96-103页

作者： Zhiping HUANG Shutian LIU Xianda HOU Shuojin WANG Hongyan ZHENG Jian DING Changhong MI Ling LU Yanlin HOU Agro-Environmental Protection Institute Ministry of Agriculture and Rural AffairsTianjin 300191China Guangxi Geographical Indication Crops Research Center of Big Data Mining and Experimental Engineering Technology Nanning Normal UniversityNanning 530001China Guangxi Key Laboratory of Earth Surface Processes and Intelligent Simulation Nanning Normal UniversityNanning 530001China Key Laboratory of Environment Change and Resources Use in Beibu Gulf(Nanning Normal University) Nanning 530001China

This paper analyzed the modeling principle,process and application process of the new ecological balanced fertilization model by data mining method based on the relationships among soil abundance-deficiency index,optimum fertilization amount and nutrient conversion rate of N,P,K for rice,wheat and maize in column *** results and conclusions were as follows:①on the basis of two ecological balanced fertilization models(available and total nutrients),a prediction model system of optimum fertilization amount based on nutrient conversion rate was established,including 3 *** first model predicted the optimum fertilization amount based on nutrient conversion rate,and the second model determined prediction difference value of optimum fertilization amount in the first amendment based on optimum yield,and the third model determined prediction difference value of optimum fertilization amount in the second amendment based on nutrient conversion rate.②Nutrient conversion rate and optimum yield were the common parameters of two models based on contents of available and total nutrients,and they were the core parameters of ecological balanced fertilization *** the specific application,the nutrient conversion rate and optimum yield were determined mainly based on the comprehensive comparison between the regional or similar plot or one plot and the experimental plot.③The two error amendments were due to the use of the fixed nutrient removal of 100 kg seeds,and underestimated the nutrient conversion rate when higher optimum production and overestimated the nutrient conversion rate when lower optimum production.④It was proposed that the nutrient conversion rate was regarded as a comprehensive nutrient index(abundance-deficiency)of ecological balanced *** was not only a parameter to measure fertilizer efficiency,but also a parameter to measure the abundance-deficiency of nutrients,and a parameter to guide fertilization.

关键词： Optimum yield Optimum fertilization amount Nutrient conversion rate Fertilizer utilization ratio Relative abundance-deficiency value of soil nutrient

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