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Sustainable Power and Energy Conference (iSPEC)

作者： Liu Cui Guangqiang Peng Jingsong He Jiyang Wu Chizu Mao Ning Jiao State Key Laboratory of HVDC Electric Power Research Institute China Southern Power Grid GuangZhou China Guangdong Provincial Key Laboratory of Intelligent Operation and Control for New Energy Power System GuangZhou China CSG Key Laboratory for Power System Simulation Electric Power Research Institute China Southern Power Grid GuangZhou China Maintenance & Test Center EHV Power Transmission Company Guangzhou CSGKEY LABORATORY FOR DC TRANSMISSIONEQUIPMENT STATE EVALUATION AND FAULT DIAGNOSIS GuangZhou China College of Electrical Engineering and Information Technology Sichuan University Chengdu China

ISBN: (纸本)9781665414401

Modular multilevel converter (MMC) is currently the most concerned voltage source converter topology in the field of flexible direct current transmission (VSC-HVDC). Due to its non-linear characteristics, harmonic components will inevitably be generated in AC and DC systems, which may affect the operation of equipment and system, cause protection equipment to malfunction, and cause interference to neighboring communications. The MMC converter is a non-linear device, which can be considered as an amplifying modulator with voltage and current conversion functions. The AC and DC networks are coupled to each other through the MMC converter to generate dynamic harmonic interaction. In recent years, harmonic instability problems have appeared in many VSC-HVDC projects. Compared with other converter topologies, the transfer relationship of harmonics on the AC and DC sides of MMC converters has not been studied in depth. In this paper, by studying the AC/DC harmonic conversion characteristics of MMC converters, it reveals the conversion law of MMC converters between AC/DC harmonics; through theoretical derivation, the quantitative calculation method of MMC harmonic transmission process is given. PSCAD simulation results prove the correctness of the above results.

关键词： Network topology Simulation Bridge circuits Voltage Power system harmonics Harmonic analysis Frequency conversion

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Human-like Walking of a Biped Robot Actuated by Pneumatic Artificial Muscles and Springs*

Human-like Walking of a Biped Robot Actuated by Pneumatic Ar...

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IEEE International Conference on Automation Science and engineering (CASE)

作者： Yixiang Liu Qing Bi Xizhe Zang Yibin Li School of Control Science and Engineering Shandong University Jinan China State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin China Engineering Research Center of Intelligent Unmanned System Ministry of Education Jinan China Shandong Institute of Advanced Technology Chinese Academy of Sciences Jinan China

ISBN: (数字)9781728169040

ISBN: (纸本)9781728169057

Human walking gait is much more natural looking and energy efficient compared with biped robots. This paper presents a bio-inspired approach to realizing more human-like biped robotic walking. For this purpose, a biped robot actuated coordinately by pneumatic artificial muscles and springs is developed, capable of exploiting passive compliance of the mechanical system in locomotion. And a control scheme for human-like walking is designed based on finite state machine. Experiments show that the biped robot can walk stably on the treadmill even with some small obstacles. The realized gait has the important features of human walking, including heel strike and toe off, stretched knees, and variation in the height of the body's center of mass, which demonstrates the effectiveness of the proposed approach.

关键词： Conferences Automation Computer aided software engineering

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Blind source extraction based on EMD and temporal correlation for rolling element bearing fault diagnosis

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Smart and Resilient Transportation 2021年第1期3卷 52-65页

作者： Xuejun Zhao Yong Qin Hailing Fu Limin Jia Xinning Zhang State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing China Beijing Research Center of Urban Traffic Information Sensing and Service Technologies Beijing Jiaotong University Beijing China and National Engineering Laboratory for System Safety and Operation Assurance of Urban Rail Transit Guangzhou China Structural Integrity and Health Monitoring Group Department of Aeronautics Imperial College London UK London China Railway Rolling Stock Corporation Limited Beijing China

Purpose Fault diagnosis methods based on blind source separation (BSS) for rolling element bearings are necessary tools to prevent any unexpected accidents. In the field application, the actual signal acquisition is usually hindered by certain restrictions, such as the limited number of signal channels. The purpose of this study is to fulfill the weakness of the existed BSS method. Design/methodology/approach To deal with this problem, this paper proposes a blind source extraction (BSE) method for bearing fault diagnosis based on empirical mode decomposition (EMD) and temporal correlation. First, a single-channel undetermined BSS problem is transformed into a determined BSS problem using the EMD algorithm. Then, the desired fault signal is extracted from selected intrinsic mode functions with a multi-shift correlation method. Findings Experimental results prove the extracted fault signal can be easily identified through the envelope spectrum. The application of the proposed method is validated using simulated signals and rolling element bearing signals of the train axle. Originality/value This paper proposes an underdetermined BSE method based on the EMD and the temporal correlation method for rolling element bearings. A simulated signal and two bearing fault signal from the train rolling element bearings show that the proposed method can well extract the bearing fault signal. Note that the proposed method can extract the periodic fault signal for bearing fault diagnosis. Thus, it should be helpful in the diagnosis of other rotating machinery, such as gears or blades.

关键词： Fault diagnosis Blind source extraction Signal decomposition Temporal correlation

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Sliding sequential CVAE with time variant socially-aware rethinking for trajectory prediction

arXiv

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arXiv 2021年

作者： Zhou, Hao Ren, Dongchun Yang, Xu Fan, Mingyu Huang, Hai National Key Laboratory of Science and Technology of Underwater Vehicle Harbin Engineering University Harbin China State Key Laboratory of Management and Control for Complex System Institute of Automation Chinese Academy of Sciences Beijing China Research Center for Autonomous Vehicles Meituan Beijing China College of Computer Science Wenzhou University Wenzhou China National Key Laboratory of Science and Technology of Underwater Vehicle Harbin Engineering University Harbin China

Pedestrian trajectory prediction is a key technology in many applications such as video surveillance, social robot navigation, and autonomous driving, and significant progress has been made in this research topic. However, there remain two limitations of previous studies. First, with the continuation of time, the prediction error at each time step increases significantly, causing the final displacement error to be impossible to ignore. Second, the prediction results of multiple pedestrians might be impractical in the prediction horizon, i.e., the predicted trajectories might collide with each other. To overcome these limitations, this work proposes a novel trajectory prediction method called CSR, which consists of a cascaded conditional variational autoencoder (CVAE) module and a socially-aware regression module. The cascaded CVAE module first estimates the future trajectories in a sequential pattern. Specifically, each CVAE concatenates the past trajectories and the predicted points so far as the input and predicts the location at the following time step. Then, the socially-aware regression module generates offsets from the estimated future trajectories to produce the socially compliant final predictions, which are more reasonable and accurate results than the estimated trajectories. Moreover, considering the large model parameters of the cascaded CVAE module, a slide CVAE module is further exploited to improve the model efficiency using one shared CVAE, in a slidable manner. Experiments results demonstrate that the proposed method exhibits improvements over state-of-the-art method on the Stanford Drone Dataset (SDD) and ETH/UCY of approximately 38.0% and 22.2%, respectively. © 2021, CC BY.

关键词： Trajectories

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Typhoon-Induced Stormwater Drives Nutrient Dynamics and Triggers Phytoplankton Blooms in Laizhou Bay, China

SSRN

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SSRN 2023年

作者： Li, Hongguan Li, Shanshan Zhang, Mingzheng Li, Xiuren Xu, Zehao Ma, Haoyang Liang, Shengkang Song, Dehai Li, Junlong Ma, Yuanqing Qin, Huawei Ji, Diansheng Frontiers Science Center for Deep Ocean Multispheres and Earth System Key Laboratory of Marine Chemistry Theory and Technology Ministry of Education Ocean University of China Qingdao266100 China College of Chemistry and Chemical Engineering Ocean University of China Qingdao266100 China College of Oceanic and Atmospheric Sciences Ocean University of China Qingdao266100 China Laboratory for Marine Ecology and Environmental Science Qingdao National Laboratory for Marine Science and Technology Qingdao266237 China Key Laboratory of Physical Oceanography Ocean University of China Ministry of Education Qingdao National Laboratory for Marine Science and Technology Qingdao China State Environmental Protection Key Laboratory of Quality Control in Environmental Monitoring China National Environmental Monitoring Center Beijing100012 China Shandong Marine Resources and Environment Research Institute Yantai264000 China National Marine Environmental Monitoring Center China

The heavy rainfall brought by typhoons result in pulsed inputs of freshwater and nutrients, causing drastic changes in the offshore hydrographic and biogeochemical conditions in a short time. In this study, we evaluated the heavy rainfall impact of Typhoons Rumbia and Lekima on Laizhou Bay (LZB). We found that torrential rainfall significantly modified riverine nutrient concentrations, component ratios, and fluxes. Our results demonstrated that 9% and 16% of the annual riverine total nitrogen (TN) and total phosphorus (TP) fluxes were transported to the LZB within two weeks in Rumbia, and the proportions were 17% and 35% in Lekima, respectively. Influenced by terrestrial inputs, the sea surface temperature (SST) and sea surface salinity (SSS) decreased postRumbia, while the dissolved inorganic nitrogen (DIN) increased from 0.13 ± 0.13 mg/L to 0.47 ± 0.32 mg/L. Furthermore, the SST and SSS decreased by approximately 2.5 ℃ and 2.3 psu postLekima, and the concentration of DIN increased from 0.13 ± 0.08 mg/L to 0.58 ± 0.48 mg/L, which induced subsequent diatom blooms. However, rapid luxury uptake of dissolved inorganic phosphorus (DIP) by phytoplankton resulted in the LZB remaining under P-limited conditions. Freshwater and nutrient pulse input accelerated the growth of highly adaptable and small diatoms in coastal waters, and the dominant species transitioned to Skeletonema costatum after Lekima. We suggest that excess freshwater inputs alter the hydrodynamic structure and residence time, combined with other suitable factors, resulting in a dramatic increase in Noctiluca scintillans and the formation of harmful algal blooms (HABs) after a decline in diatom blooms. © 2023, The Authors. All rights reserved.

关键词： Nutrients

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Living Near More Greenness Associated with Increased Bone Strength: A Large Epidemiological Study in China

SSRN

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SSRN 2022年

作者： Jiang, Ye Kang Zhuo, Bai Ma Guo, Bing Zeng, Pei-Bin Guo, Yu-Ming Chen, Gong-Bo Wei, Jing He, Rui-Feng Li, Zhi-Feng Zhang, Xue-Hui Wang, Zi-Yun Li, Xuan Wang, Lei Zeng, Chun-Mei Chen, Lin Xiao, Xiong Zhao, Xing West China School of Public Health and West China Fourth Hospital Sichuan University Sichuan Chengdu China Division of Pulmonary Diseases State Key Laboratory of Biotherapy West China Hospital of Sichuan University Sichuan Chengdu China School of Medicine Tibet University Tibet Lhasa China Department of Epidemiology and Preventive Medicine School of Public Health and Preventive Medicine Monash University MelbourneVIC3004 Australia Guangdong Provincial Engineering Technology Research Center of Environmental and Health Risk Assessment Department of Occupational and Environmental Health School of Public Health Sun Yat-sen University Guangdong Guangzhou China Department of Atmospheric and Oceanic Science Earth System Science Interdisciplinary Center University of Maryland College ParkMD United States Tibet Center for Disease Control and Prevention Tibet Lhasa China Chongqing Municipal Center for Disease Control and Prevention Chongqing China School of public Health Kunming Medical University Yunnan Kunming China School of Public Health The key Laboratory of Environmental Pollution Monitoring and Disease Control Ministry of Education Guizhou Medical University Guiyang550025 China Jianyang Center for Disease Control and Prevention Sichuan Chengdu China

Background Numerous studies show that living near more greenness may benefit various health outcomes. Nevertheless, no studies have investigated the greenness-bone linkage in the general population with large sample sizes. Moreover, to what extent ambient air pollution (AAP) and physical activity (PA) mediate this relationship is unclear. We aimed to explore the association between greenness and bone strength in Chinese adults and the potential mediating role of AAP and PA behind it. Methods A total of 66,102 adults from the China Multi-Ethnic Cohort (CMEC) in 2018-2019 were enrolled. The Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) were employed as the residential greenness definition. Calcaneus quantitative ultrasound index (QUI) was regarded as an indicator of bone strength. Multiple linear regression models and causal mediation analyses were used to estimate the residential greenness-bone strength association and the potential pathways operating through PA and AAP. Stratification analyses were also adopted to identify susceptible populations. Results Increased residential exposure to greenness were significantly associated with higher QUI, with changes (95% confidence interval) of 3.04 (2.81, 3.26), 3.35 (3.12, 3.58), 2.44 (2.22, 2.66), and 2.71 (2.49, 2.93) for every interquartile range (IQR) increased in NDVI 500m , NDVI 1000m , EVI 500m , EVI 1000m , respectively. Gender, urbanicity, and annual family income significantly modified the links of greenness and bone strength, with more remarkable associations in males, urban residents, and subjects with higher family income. In the NDVI 500m /EVI 500m -QUI relationship, the mediating role of AAP was high reached 39.19% and 52.53%, while that of PA was only 1.64% and 1.68%. Conclusion Living in a greener place may improve bone strength, especially among males, urban residents, and the wealthier. These protective effects may be mainly operated by reducing the hazard effects of A

关键词： Housing

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Data-driven parametric design of additively manufactured hybrid lattice structure for stiffness and wide-band damping performance

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Additive Manufacturing Frontiers 2025年第2期4卷

作者： Chenyang Li Shangqin Yuan Han Zhang Shaoying Li Xinyue Li Jihong Zhu State IJR Center of Aerospace Design and Additive Manufacturing School of Mechanical Engineering Northwestern Polytechnical University Xi'an 710072 China Key Laboratory of Metal High-Performance Additive Manufacturing and Innovative Design MIIT China Northwestern Polytechnical University Xi'an 710072 China Institute of Intelligence Material and Structure Unmanned System Research Institute Northwestern Polytechnical University Xi'an 710072 China Aircraft Strength Research Institute of China Xi'an 710065 China Modern Control Technology Research Institute Xi'an 710065 China

The outstanding comprehensive mechanical properties of newly developed hybrid lattice structures make them useful in engineering applications for bearing multiple mechanical loads. Additive-manufacturing technologies make it possible to fabricate these highly spatially programmable structures and greatly enhance the freedom in their design. However, traditional analytical methods do not sufficiently reflect the actual vibration-damping mechanism of lattice structures and are limited by their high computational cost. In this study, a hybrid lattice structure consisting of various cells was designed based on quasi-static and vibration experiments. Subsequently, a novel parametric design method based on a data-driven approach was developed for hybrid lattices with engineered properties. The response surface method was adopted to define the sensitive optimization target. A prediction model for the lattice geometric parameters and vibration properties was established using a backpropagation neural network. Then, it was integrated into the genetic algorithm to create the optimal hybrid lattice with varying geometric features and the required wide-band vibration-damping characteristics. Validation experiments were conducted, demonstrating that the optimized hybrid lattice can achieve the target properties. In addition, the data-driven parametric design method can reduce computation time and be widely applied to complex structural designs when analytical and empirical solutions are unavailable.

关键词： Hybrid lattice structure Data-driven Wide-band damping Machine-learning method

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Localization and Surface Characterization by Zhurong Mars Rover at Utopia Planitia

Research Square

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research Square 2021年

作者： Ding, Liang Zhou, Ruyi Yu, Tianyi Gao, Haibo Yang, Huaiguang Li, Jian Yuan, Ye Liu, Chuankai Wang, Jia Zhao, Yuyan Wang, Zhengyin Wang, Xiyu Bao, Gang Deng, Zongquan Huang, Lan Li, Nan Cui, Xiaofeng He, Ximing Jia, Yang Yuan, Baofeng Liu, Guangjun Zhang, Hui Zhao, Rui Zhang, Zuoyu Cheng, Ziqing Wu, Fan Xu, Qian Lu, Hao Richter, Lutz Liu, Zhen Niu, Fuliang Qi, Huanan Li, Shu Feng, Wenhao Yang, Chaojie Chen, Baichao Dang, Zhaolong Zhang, Mingming Li, Lichun Wang, Xiaoxue Huang, Zhao Zhang, Jitao Xing, Hongjun Wang, Guanyu Niu, Lizhou Xu, Peng Wan, Wenhui Di, Kaichang State Key Laboratory of Robotics and System Harbin Institute of Technology Harbin150080 China Beijing Aerospace Control Center Beijing100094 China Center for Lunar and Planetary Sciences Institute of Geochemistry Chinese Academy of Science Guiyang550081 China CAS Center for Excellence in Comparative Planetology Hefei230026 China University of Chinese Academy of Sciences Beijing100049 China Beijing Institute of Spacecraft System Engineering Beijing100094 China Department of Aerospace Engineering Ryerson University TorontoONM5B 2K3 Canada Hauptstrasse 1e Eching Germany State Key Laboratory of Remote Sensing Science Aerospace Information Research Institute Chinese Academy of Sciences Beijing100101 China

China’s first Mars rover, Zhurong, has successfully touched down on the southern Utopia Planitia of Mars at 109.925° E, 25.066° N, and since performed cooperative multiscale investigations with the Tianwen-1 orbiter. Here we present primary localization and surface characterization results based on complementary data of the first 60 sols. The Zhurong rover has traversed 450.9 m southwards over a flat surface with mild wheel slippage (less than 0.2 in slip ratio). The encountered crescent-shaped sand dune indicates a NE-SW local wind direction, consistent with larger-range remote-sensing observations. Soil parameter analysis based on terramechanics indicates that the topsoil has high bearing strength and cohesion, and its equivalent stiffness and internal friction angle are ~1390-5872 kPa∙m-n and ~21°-34° respectively. Rocks observed strewn with dense pits, or showing layered and flaky structures, are presumed to be involved in physical weathering like severe wind erosion and potential chemical weathering processes. These preliminary observations suggest great potential of in-situ investigations by the scientific payload suite of the Zhurong rover in obtaining new clues of the region’s aeolian and aqueous history. Cooperative investigations using the related payloads on both the rover and the obiter could peek into the habitability evolution of the northern lowlands on Mars. © 2021, CC BY.

关键词： Sols

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Could the Recent Taal Volcano Eruption Trigger an El Ni?o and Lead to Eurasian Warming?

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Advances in Atmospheric Sciences 2020年第7期37卷 663-670页

作者： Fei LIU Chen XING Jinbao LI Bin WANG Jing CHAI Chaochao GAO Gang HUANG Jian LIU Deliang CHEN School of Atmospheric Sciences and Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies Sun Yat-sen UniversityZhuhai 519082China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519082China Earth System Modeling and Climate Dynamics Research Center Nanjing University of Information Science and TechnologyNanjing 210044China Department of Geography University of Hong KongPokfulamHong Kong Department of Atmospheric Sciences and International Pacific Research Center University of Hawaii at ManoaHonoluluHI 96822USA Department of Environmental Science Zhejiang UniversityHangzhou 310058China State key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Key Laboratory for Virtual Geographic Environment Ministry of EducationJiangsu Provincial State Key Laboratory Cultivation Base of Geographical Environment EvolutionSchool of Geography ScienceNanjing Normal UniversityNanjing 210023China Department of Earth Sciences University of GothenburgGothenburg 40530Sweden

The Taal Volcano in Luzon is one of the most active and dangerous volcanoes of the Philippines.A recent eruption occurred on 12 January 2020(Fig.1a),and this volcano is still active with the occurrence of volcanic *** eruption has become a deep concern worldwide,not only for its damage on local society,but also for potential hazardous consequences on the Earth’s climate and environment.

关键词： Volcano Philippines worldwide

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Investigating the role of aerosol wet scavenging on global horizontal irradiance simulation in the WRF-Chem-solar model

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Applied Energy 2025年 396卷

作者： Su Wang Gang Huang Tie Dai Junji Cao Letu Husi Run Ma Cuina Li State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China State Key Laboratory of Earth System Numerical Modeling and Application Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China University of Chinese Academy of Sciences Beijing 100049 China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC-FEMD) Nanjing University of Information Science and Technology Nanjing 210044 China Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China State Key Laboratory of Remote Sensing Science Aerospace Information Research Institute Chinese Academy of Sciences Beijing 100081 China Artificial Intelligence Key Laboratory of Sichuan Province Sichuan University of Science & Engineering Yibin 644005 China Meteorological Observation Center of China Meteorological Administration Beijing 100081 China

Solar energy emerges as a vital renewable resource with profound implications for future energy consumption. To improve the accuracy of global horizontal irradiance (GHI) simulation, this study integrates the Thompson and Eidhammer aerosol-aware cloud microphysics scheme with the aerosol module Goddard Ozone Chemistry Aerosol Radiation and Transport (GOCART) in the WRF-Solar model. Based on the new coupled aerosol-cloud interaction, a physical parametric aerosol wet scavenging scheme is developed to investigate its effects on aerosol and GHI simulations. Our results demonstrate that the updated wet removal enhances the spatial representation of aerosol optical depth (AOD) across China, particularly in regions influenced by anthropogenic aerosols such as Northern, Central and Eastern China. The average absolute mean bias (BIAS) value for AOD decreases by 20.00 %, leading to a 36.47 % improvement in reducing the overestimation of GHI under clear sky. The most remarkable BIAS reductions occur in Central (104.30 %), Western (45.70 %), and Eastern China (41.42 %) for GHI under clear sky, especially in high surface solar radiation zones (>500 W/m 2 ). Similar improvements are observed for GHI under all-sky conditions, with a national relative improvement of 29.91 %. Central, Eastern, and Western China show the most substantial BIAS reductions, with relative decreases of 57.48 %, 50.62 %, and 32.40 %, respectively. Overall, this study highlights the potential of the enhanced aerosol wet scavenging scheme to improve GHI simulation accuracy, providing valuable insights for advancing renewable energy initiatives.

关键词： Radiation damage

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