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Characterization and prediction of tailpipe ammonia emissions from in-use China 5/6 light-duty gasoline vehicles

Frontiers of Environmental Science & engineering 2024年第1期18卷 71-81页

作者： Lewei Zeng Fengbin Wang Shupei Xiao Xuan Zheng Xintong Li Qiyuan Xie Xiaoyang Yu Cheng Huang Qingyao Hu Yan You Ye Wu College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen 518060China State Key Laboratory of Engines Tianjin UniversityTianjin 300072China China Automotive Technology and Research Center Co.Ltd. Tianjin 300300China CATARC Automotive Test Center(Guangzhou)Co.Ltd. Guangzhou 511300China State Environmental Protection Key Laboratory of Cause and Prevention of Urban Air Pollution Complex Shanghai Academy of Environmental SciencesShanghai 200233China National Observation and Research Station of Coastal Ecological Environments in Macao Macao Environmental Research InstituteMacao University of Science and TechnologyMacao SAR 999078China School of Environment State Key Joint Laboratory of Environment Simulation and Pollution ControlTsinghua UniversityBeijing 100084China

On-road tailpipe ammonia (NH3) emissions contribute to urban secondary organic aerosol formation and have direct or indirect adverse impacts on the environment and human health. To understand the tailpipe NH3 emission characteristics, we performed comprehensive chassis dynamometer measurements of NH3 emission from two China 5 and two China 6 light-duty gasoline vehicles (LDGVs) equipped with three-way catalytic converters (TWCs). The results showed that the distance-based emission factors (EFs) were 12.72 ± 2.68 and 3.18 ± 1.37 mg/km for China 5 and China 6 LDGVs, respectively. Upgrades in emission standards were associated with a reduction in tailpipe NH3 emission. In addition, high NH3 EFs were observed during the engine warm-up period in cold-start cases owing to the intensive emissions of incomplete combustion products and suitable catalytic temperature in the TWCs. Notably, based on the instantaneous NH3 emission rate, distinct NH3–emitting events were detected under high/extra high velocity or rapid acceleration. Furthermore, NH3 emission rates correlated well with engine speed, vehicle specific power, and modified combustion efficiency, which were more easily accessible. These strong correlations were applied to reproduce NH3 emissions from China 5/6 LDGVs. The predicted NH3 EFs under different dynamometer and real-world cycles agreed well with existing measurement and prediction results, revealing that the NH3 EFs of LDGVs in urban routes were within 8.55–11.62 mg/km. The results presented here substantially contribute to improving the NH3 emission inventory for LDGVs and predicting on-road NH3 emissions in China.

关键词： NH3 instantaneous emissions Catalytic temperature Vehicle specific power Combustion efficiency Emission prediction

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Prototype Guided Personalized Federated Intrusion Detection system 10

Prototype Guided Personalized Federated Intrusion Detection ...

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10th IEEE Smart World Congress, SWC 2024

作者： Cheng, Long Yan, Huiru Zhou, Hanlin Wang, Ying Tang, Haichuan Fang, Fang North China Electric Power University State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources School of Control and Computer Engineering Beijing China Institute of Computing Technology Chinese Academy of Sciences Beijing China Ai Lab of Crrc Academy Beijing China

ISBN: (纸本)9798331520861

Preventing network attacks and protecting user privacy are consistently hot research topics in the Internet of Things (IoT) and edge computing fields. Recent advancements in Federated Learning (FL) have shown promise in addressing these challenges. FL allows various clients to collaboratively build an intrusion detection system (IDS) without sharing their private data. However, most existing methods train a single intrusion detection model for all clients and assume that the training and test data distribution are identical, leading to unsatisfactory detection accuracy and generalization abilities in practice. To overcome these challenges, this paper introduces a prototype-guided personalized FL approach named PG-FedIDS. We propose two novel mechanisms within this method. Firstly, we utilize class prototypes as auxiliary information carriers to generate personalized models for each client, rather than generating a single global model as in previous works. Secondly, we propose a prototype-guided ensemble learning strategy, which can leverage the global knowledge in prototypes to enhance detection accuracy and generalization abilities for each client. We conduct extensive experiments on two benchmark datasets with different evaluation test settings. The results demonstrate that our PG-FedIDS achieves promising detection accuracy and consistently outperforms other FL baselines. © 2024 IEEE.

关键词： Federated learning

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Reliability-Based Topology Optimization of Fail-Safe Structures Using Moving Morphable Bars

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Computer Modeling in engineering & Sciences 2023年第9期136卷 3173-3195页

作者： Xuan Wang Yuankun Shi Van-Nam Hoang Zeng Meng Kai Long Yuesheng Wang School of Mechanical Engineering Tianjin UniversityTianjin300072China Department of Engineering Mechanics Hefei University of TechnologyHefei230009China Mechanical Engineering Institute Vietnam Maritime UniversityHai Phong City180000Vietnam State Key Laboratory for Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing102206China

This paper proposes an effective reliability design optimizationmethod for fail-safe topology optimization(FSTO)considering uncertainty based on the moving morphable bars method to establish the ideal balance between cost and robustness,reliability and structural *** this end,a performancemeasure approach(PMA)-based doubleloop optimization algorithmis developed tominimize the relative volume percentage while achieving the reliability *** ensure the compliance value of the worst failure case can better approximate the quantified design requirement,a p-norm constraint approach with correction parameter is ***,the significance of accounting for uncertainty in the fail-safe design is illustrated by contrasting the findings of the proposed reliabilitybased topology optimization(RBTO)method with those of the deterministic design method in three typical *** Carlo simulation shows that the relative error of the reliability index of the optimized structure does not exceed 3%.

关键词： Topology optimization fail-safe design uncertainty reliability-based topology optimization moving morphable bars

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Optimization Scheduling of Multi-Energy Microgrid Based on the QUBO Quantum Computing Model 19th

Optimization Scheduling of Multi-Energy Microgrid Based on t...

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19th Annual Conference of China Electrotechnical Society, ACCES 2024

作者： Wang, Baonan Wang, Hui Zhang, Dan College of Computer Science and Technology Shanghai University of Electric Power Shanghai China State Key Laboratory of Power System Operation and Control Dept. of Electrical Engineering Tsinghua University Beijing China Institute of Logistic Science and Engineering Shanghai Maritime University Shanghai China

ISBN: (纸本)9789819608966

Current optimization methods for microgrid scheduling face issues such as insufficient precision in energy distribution, high operational costs, and inefficiency. In response to these challenges, an optimization scheduling method for multi-energy microgrids based on the QUBO (Quadratic Unconstrained Binary Optimization) quantum computing model is proposed in this paper, alongside a discretization approach based on a grid partitioning strategy. To validate the feasibility of addressing microgrid optimization scheduling problems in a quantum computing environment, a QUBO model is constructed and simulation studies are conducted in the qbsolv environment provided by D-Wave. The results indicate that operational costs are significantly reduced with an increase in the number of grids, particularly a reduction of 4.52% when the number of grids increases from five to ten. This method not only effectively enhances the precision of electricity supply and energy utilization efficiency but also reduces unnecessary electrical waste and economic costs. © beijing Paike Culture Commu. Co., Ltd. 2025.

关键词： Microgrids

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Deciphering decadal urban ozone trends from historical records since 1980

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National Science Review 2024年第11期11卷 117-129页

作者： Haolin Wang Xiao Lu Paul I.Palmer Lin Zhang Keding Lu Ke Li Tatsuya Nagashima Ja-Ho Koo Hiroshi Tanimoto Haichao Wang Meng Gao Cheng He Kai Wu Shaojia Fan Yuanhang Zhang School of Atmospheric Sciences Sun Yat-sen University and Key Laboratory of Tropical Atmosphere-Ocean System Ministry of Education Guangdong Provincial Observation and Research Station for Climate Environment and Air Quality Change in the Pearl River Estuary Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) School of Geo Sciences University of Edinburgh National Centre for Earth Observation University of Edinburgh Laboratory for Climate and Ocean-Atmosphere Studies Department of Atmospheric and Oceanic SciencesSchool of PhysicsPeking University State Key Joint Laboratory of Environmental Simulation and Pollution Control The State Environmental Protection Key Laboratory of Atmospheric Ozone Pollution ControlCollege of Environmental Sciences and Engineering Peking University Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Collaborative Innovation Center of Atmospheric Environment and Equipment Technology School of Environmental Science and Engineering Nanjing University of Information Science &Technology National Institute for Environmental Studies Department of Atmospheric Sciences Yonsei University Department of Geography Hong Kong Baptist University Department of Civil and Environmental Engineering University of California

Ozone pollution is a major environmental threat to human health. Timely assessment of ozone trends is crucial for informing environmental policy. Here we show that for the most recent decade（2013–2022） in the northern hemisphere, warm-season（April–September） mean daily 8-h average maximum ozone increases much faster in urban regions with top ozone levels(mainly in the North China Plain, 1.2 ± 1.3 ppbv year-1) than in other, low-ozone regions(0.2 ± 0.9 ppbv year-1). These trends widen the ozone differences across urban regions, and increase extreme pollution levels and health threats from a global perspective. Comparison of historical trends in different urban regions reveals that ozone increases in China during 2013–2022 differ in magnitude and mechanisms to historical periods in other regions since *** reflects a unique chemical environment characterized by exceptionally high nitrogen oxides and aerosol concentrations, where reducing ozone precursor emissions leads to substantial ozone *** increase in China has slowed down in 2018–2022 compared to 2013–2017, driven by ongoing emission reductions, but with ozone-favorable weather conditions. Historical ozone evolution in Japan and South Korea indicates that ozone increases should be suppressed with continuous emission *** temperature and associated wildfires have also reversed ozone decreases in the USA and Europe,with anthropogenic ozone control slowing down in recent decades.

关键词： air quality surface ozone trends

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Analysis on Local and Concurrent Commutation Failure of Multi-infeed HVDC Considering Inter-converter Interaction

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Journal of Modern Power systems and Clean Energy 2022年第4期10卷 1050-1059页

作者： Bilawal Rehman Chongru Liu Huan Li Chuang Fu Wei Wei State Key Laboratory for Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China Department of Electrical Engineering Technology National Skills University IslamabadIslamabad45710Pakistan State Key Laboratory of HVDC Electric Power Research InstituteChina Southern Power GridGuangzhou 510663China

This paper provides a comprehensive analysis of local and concurrent commutation failure(CF)of multi-infeed high-voltage direct current(HVDC)system considering multi-infeed interaction factor(MIIF).The literature indicates that the local CF is not influenced by MIIF,whereas this paper concludes that both the local CF and concurrent CF are influenced by *** ability of remote converter to work under reduced reactive power enables its feature to support local converter via inter-connection *** MIIF measures the strength of electrical connectivity between *** MIIF gives a clearer path to remote converter to support local converter,but at the same time,it provides an easy path to local converter to disturb remote converter under local *** presence of nearby converter increases the local commutation failure immunity index(CFII)while reducing concurrent *** MIIF causes reactive power support to flow from remote converter to local converter,which reduces the chances of CF.A mathematical approximation to calculate the increase in local CFII for multi-infeed HVDC configurations is also proposed.A power flow approach is used to model the relation between MIIF and reactive power support from remote *** local and concurrent CFIIs are found to be inverse to each other over MIIF;therefore,it is recommended that there is an optimal value of MIIF for all converters in close electric proximity to maintain CFII at a certain *** numerical results of established model are compared with PSCAD/EMTDC *** simulation results show the details of the influence of MIIF on local CF and concurrent CF of multi-infeed HVDC,which validates the analysis presented.

关键词： Commutation failure(CF) multi-infeed highvoltage direct current(HVDC)system multi-infeed interaction factor commutation failure immunity index(CFII)

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数据驱动框架下基于基因表达编程的非线性K-L湍流混合模型

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Acta Mechanica Sinica 2023年第2期39卷 147-164页

作者：谢寒松赵耀民张又升 Key Laboratory of High Energy Density Physics Simulation Ministry of EducationCenterfor Applied Physics and Technology and College of EngineeringPeking UniversityBeijing 100871China State Key Laboratory for Turbulence and Complex Systems College of EngineeringPeking UniversityBeijing 100871China institute of Applied Physics and Computational Mathematics Beijing 100094China

由Rayleigh-Taylor(RT)、Richtmyer-Meshkov(RM)、Kelvin-Helmholtz(KH)等流体力学界面不稳定性诱导的湍流混合现象广泛存在于自然界和工程问题中,准确预测其演化具有十分重要的意义.考虑到实际问题的高雷诺数及复杂性,在可预见的未来,... 详细信息

由Rayleigh-Taylor(RT)、Richtmyer-Meshkov(RM)、Kelvin-Helmholtz(KH)等流体力学界面不稳定性诱导的湍流混合现象广泛存在于自然界和工程问题中,准确预测其演化具有十分重要的意义.考虑到实际问题的高雷诺数及复杂性,在可预见的未来,雷诺平均(RANS)方法仍将是工程实践中最具可实现性的选择.一般而言,传统RANS混合模型中至关重要的雷诺应力项是基于经典的Boussinesq线性涡粘假设封闭的.然而,这种线性模型无法充分描述在实际工程流动中发挥着重要作用的湍流各向异性特征.相比之下,非线性模型在这方面具有显著优势.本研究首次将基因表达编程(GEP)方法应用于湍流混合问题,发展了数据驱动的非线性K-L湍流混合模型.与常见的“黑箱”型机器学习模型不同,GEP模型显式给出模型方程,从而具有更强的物理可解释性.具体地,本研究基于二阶截断的广义Cayley-Hamilton非线性本构关系,利用GEP方法中的符号回归功能,形式化地给出了待封闭的模型系数与伽利略不变量之间的函数关系.此外,为了保证训练模型的物理性,我们将可实现性原则引入到了惩罚函数中.模型泛化性测试的结果表明:尽管新模型仅利用倾斜RT混合问题训练得到,但对于几个典型的混合问题均具有良好的鲁棒性.与标准的K-L模型相比,新模型不但具有更高的预测精度,而且能够更好地捕捉湍流的物理特性.此外,通过分析显式的封闭模型,本文进一步给出了新模型的预测效果得以提升的原因.

关键词： Turbulent mixing GEP method Nonlinear model Machine learning Interpretable model

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Progress in models for coupled human and natural systems

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Science China Earth Sciences 2024年第11期67卷 3631-3637页

作者： Tianxiang YUE Chenchen WU Wenjiao SHI Yongzhong TIAN Qing WANG Yimin LU Lili ZHANG State Key Laboratory of Resources and Environment Information System Institute of Geographical Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China College of Resources and Environment University of Chinese Academy of SciencesBeijing 101408China School of Geographical Sciences Southwest UniversityChongqing 400715China National Institute of Environmental Health Chinese Center for Disease Control and PreventionBeijing 100021China National Engineering Research Center of Geospatial Information Technology Fuzhou UniversityFuzhou 350108China The Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China

1. Introduction Malthus (1798) was one of the earliest researchers to propose a coupled human-natural system (CHANS) model, particularly in his analysis of the relationship between population growth and food supply. He argued that while population grows geometrically, food supply increases only arithmetically, suggesting that this imbalance could eventually lead to a food crisis due to diminishing per capita food availability (Malthus, 1798).

关键词： Malthus eventually population

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Prediction of Railway Track Curvature Using OpenStreetMap 3

Prediction of Railway Track Curvature Using OpenStreetMap

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3rd International Conference on Rail Transportation, ICRT 2024

作者： Zhou, Yichang Ren, Zunsong Ye, Yunguang Hecht, Markus School of Mechanical Electronic and Control Engineering Beijing Jiaotong Univ. Beijing China State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong Univ. Chengdu China Institute of Land and Sea Transport Systems Technische Universität Berlin Berlin Germany

ISBN: (数字)9780784485941

ISBN: (纸本)9780784485941

Railway track curvature is a critical parameter, which directly affects vehicle-track dynamics, such as running speed and wheel-rail interaction. Therefore, knowing track curvature can help wagon operators better understand the running condition of vehicles and further take effective measures to monitor or maintain their health. This paper aims to predict horizontal track curvature by using OpenStreetMap (OSM), an open and free geographic database. A field test was carried out when a train was operated on the Blankenburg-Bernburg railway line in Germany. At first, the running trajectory of the vehicle is measured by the GPS sensor with a frequency of 5 Hz and then it is converted to Cartesian coordinates, where the curvature of the trajectory is calculated. Second, an improved method to increase the accuracy by integrating with the OSM database is proposed, and the procedure of this improved method is presented. © ASCE.

关键词： Railroads

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A bionic approach for the mechanical and electrical decoupling of an MEMS capacitive sensor in ultralow force measurement

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Frontiers of Mechanical engineering 2023年第2期18卷 297-317页

作者： Wendi GAO Bian TIAN Cunlang LIU Yingbiao MI Chen JIA Libo ZHAO Tao LIU Nan ZHU Ping YANG Qijing LIN Zhuangde JIANG Dong SUN State Key Laboratory for Manufacturing Systems Engineering International Joint Laboratory for Micro/Nano Manufacturing and Measurement TechnologiesOverseas Expertise Introduction Center for Micro/Nano Manufacturing and Nano Measurement Technologies Discipline InnovationXi’an Jiaotong University(Yantai)Research Institute for Intelligent Sensing Technology and SystemSchool of Mechanical EngineeringXi’an Jiaotong UniversityXi’an 710049China Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing Yantai 265599China State Key Laboratory of Robotics and Systems(HIT) Harbin 150006China Beijing Advanced Innovation Center for Intelligent Robots and Systems Beijing Institute of TechnologyBeijing 100081China Department of Biomedical Engineering City University of Hong KongHong KongChina

Capacitive sensors are efficient tools for biophysical force measurement,which is essential for the exploration of cellular ***,attention has been rarely given on the influences of external mechanical and internal electrical interferences on capacitive *** this work,a bionic swallow structure design norm was developed for mechanical decoupling,and the influences of structural parameters on mechanical behavior were fully analyzed and optimized.A bionic feather comb distribution strategy and a portable readout circuit were proposed for eliminating electrostatic *** instability was evaluated,and electrostatic decoupling performance was verified on the basis of a novel measurement method utilizing four complementary comb arrays and applicationspecific integrated circuit *** electrostatic pulling experiment showed that the bionic swallow structure hardly moved by 0.770 nm,and the measurement error was less than 0.009% for the area-variant sensor and 1.118% for the gap-variant sensor,which can be easily compensated in *** proposed sensor also exhibited high resistance against electrostatic rotation,and the resulting measurement error dropped below 0.751%.The rotation interferences were less than 0.330 nm and(1.829×10^(-7))°,which were 35 times smaller than those of the traditional differential *** on the proposed bionic decoupling method,the fabricated sensor exhibited overwhelming capacitive sensitivity values of 7.078 and 1.473 pF/μm for gap-variant and area-variant devices,respectively,which were the highest among the current *** immunity to mechanical disturbances was maintained simultaneously,i.e.,less than 0.369% and 0.058% of the sensor outputs for the gap-variant and area-variant devices,respectively,indicating its great performance improvements over existing devices and feasibility in ultralow biomedical force measurement.

关键词： micro-electro-mechanical system capacitive sensor bionics operation instability mechanical and electrical decoupling biomedical force measurement

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