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作者： Zhanxin Li Zizhen Cao Wenjie Duan Yikang Du Haiteng Liu Tianjin Key Laboratory of Microgravity Environment Simulation Technology Beijing Institute of Control Engineering Science and Technology on Space Intelligent Control Laboratory

The most important interfering torque of a three-axis air-bearing simulator is the displacement of the center of mass in the gravity field caused by structural *** order to characterize the torque,a mathematical model of the interference moment was *** on the model,it is suggested that the vertical stiffness and horizontal stiffness of the structure should be equal as far as possible during the structural design,and the elastic unbalance moment can be compensated by the vertical offset of the center of mass of the air floating platform relative to the rotation center after the initial attitude *** was used to build a simulation model of the air floating platform,and the changes of the structure's centroid before and after the gravitational field was applied were extracted by software to simulate the centroid deviation caused by the elastic deformation of the structure,which was used as the characterization to conduct discrete optimization of the *** optimal structural parameters were *** the disturbance torque curve and the corresponding initial centroid offset after initial centroid compensation were calculated by mathematical *** results are of positive guiding significance to the design of three-axis air-bearing simulator.

关键词： Three-axis air-bearing simulator Unbalance torque Mass-center compensation

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Physically Based Bidirectional Path Tacing Algorithm on the Tianhe-2 Supercomputer

Physically Based Bidirectional Path Tacing Algorithm on the ...

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IEEE International Conference on High Performance Computing and Communications (HPCC)

作者： Yijia Wu Congpin Zhang Zhengwei Xu Ligang Li National Space Science Center Key Laboratory of Electronics and Information Technology for Space System Chinese Academy of Sciences Beijing China School of Computer Science and Technology University of Chinese Academy of Sciences School of Computer & Information Engineering Henan Normal University Xinxiang Henan China

Physically based ray tracing is a technique that involves creating a photo-realistic image from a 3D scene description by utilizing the laws of physics to simulate the behavior of light and matter. However, due to the random length of light samples and irregular memory access patterns, it can suffer from low scalability and severe load imbalance. As a result, the development of a framework for multi-node parallelism algorithm in physically based ray tracing is a significant challenge. To tackle these issues, this paper introduces a novel algorithm named distributed parallel physically based bidirectional path tacing algorithm (DP-BDPT). Through analyzing the physical essence of bidirectional path tracing algorithm and the light transport equation, we have devised a framework that carefully divides tasks between inter-compute nodes and intra-compute nodes. To support high scalability, we have developed a physically based architecture. Additionally, we have proposed a hybrid scheduling method to achieve load balancing. To further enhance performance, we have analyzed several key factors that affect rendering performance and implemented adaptive optimization techniques. The experiments conducted on the Tianhe-2 Supercomputer involving typical and challenging 3D scenes, namely the Cornell-box, Veach-bidir, and Teapot-full experiments, have illustrated that DP-BDPT demonstrate near-linear speedups as the number of CPU cores scales from 1200 to 9600, thereby demonstrating their efficiency when operating on a ten-thousand-core system.

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Artificial intelligence for geoscience:Progress,challenges,and perspectives

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The Innovation 2024年第5期5卷 136-160,135页

作者： Tianjie Zhao Sheng Wang Chaojun Ouyang Min Chen Chenying Liu Jin Zhang Long Yu Fei Wang Yong Xie Jun Li Fang Wang Sabine Grunwald Bryan MWong Fan Zhang Zhen Qian Yongjun Xu Chengqing Yu Wei Han Tao Sun Zezhi Shao Tangwen Qian Zhao Chen Jiangyuan Zeng Huai Zhang Husi Letu Bing Zhang Li Wang Lei Luo Chong Shi Hongjun Su Hongsheng Zhang Shuai Yin Ni Huang Wei Zhao Nan Li Chaolei Zheng Yang Zhou Changping Huang Defeng Feng Qingsong Xu Yan Wu Danfeng Hong Zhenyu Wang Yinyi Lin Tangtang Zhang Prashant Kumar Antonio Plaza Jocelyn Chanussot Jiabao Zhang Jiancheng Shi Lizhe Wang Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100094China School of Computer Science China University of GeosciencesWuhan 430078China State Key Laboratory of Mountain Hazards and Engineering Resilience Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610299China Key Laboratory of Virtual Geographic Environment(Ministry of Education of PRC) Nanjing Normal UniversityNanjing 210023China Data Science in Earth Observation Technical University of Munich80333 MunichGermany The National Key Laboratory of Water Disaster Prevention Yangtze Institute for Conservation and DevelopmentHohai UniversityNanjing 210098China Institute of Computing Technology Chinese Academy of SciencesBeijing 100190China School of Geographical Sciences Nanjing University of Information Science and TechnologyNanjing 210044China State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China Soil Water and Ecosystem Sciences DepartmentUniversity of FloridaPO Box 110290GainesvilleFLUSA Materials Science Engineering Program Cooperating Faculty Member in the Department of Chemistry and Department of Physics Astronomy University of CaliforniaCaliforniaRiversideCA 92521USA Institute of Remote Sensing and Geographical Information System School of Earth and Space SciencesPeking UniversityBeijing 100871China Key Laboratory of Computational Geodynamics University of Chinese Academy of SciencesBeijing 100049China International Research Center of Big Data for Sustainable Development Goals Beijing 100094China College of Geography and Remote Sensing Hohai UniversityNanjing 211100China Department of Geography The University of Hong KongHong Kong 999077SARChina Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control Nanjing 210044China School of Environmental Science and Engineering Nanjing University of Information Science&TechnologyNanjing 210044China Collaborative Inno

This paper explores the evolution of geoscientific inquiry,tracing the progression from traditional physics-based models to modern data-driven approaches facilitated by significant advancements in artificial intelligence(AI)and data collection *** models,which are grounded in physical and numerical frameworks,provide robust explanations by explicitly reconstructing underlying physical ***,their limitations in comprehensively capturing Earth’s complexities and uncertainties pose challenges in optimization and real-world *** contrast,contemporary data-driven models,particularly those utilizing machine learning(ML)and deep learning(DL),leverage extensive geoscience data to glean insights without requiring exhaustive theoretical *** techniques have shown promise in addressing Earth science-related ***,challenges such as data scarcity,computational demands,data privacy concerns,and the“black-box”nature of AI models hinder their seamless integration into *** integration of physics-based and data-driven methodologies into hybrid models presents an alternative *** models,which incorporate domain knowledge to guide AI methodologies,demonstrate enhanced efficiency and performance with reduced training data *** review provides a comprehensive overview of geoscientific research paradigms,emphasizing untapped opportunities at the intersection of advanced AI techniques and *** examines major methodologies,showcases advances in large-scale models,and discusses the challenges and prospects that will shape the future landscape of AI in *** paper outlines a dynamic field ripe with possibilities,poised to unlock new understandings of Earth’s complexities and further advance geoscience exploration.

关键词： Earth utilizing landscape

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全球变暖导致易诱发臭氧污染的强地面太阳辐射频率增加

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science Bulletin 2023年第4期68卷 388-392,M0003页

作者：寇文彬高阳张绍晴蔡文炬耿冠楠 Steven J.Davis 王宏郭修文程文轩曾欣然马铭晨王厚文王俏巧姚小红高会旺吴立新 Frontiers Science Center for Deep Ocean Multispheres and Earth System and Key Laboratory of Marine Environmental Science and EcologyMinistry of EducationOcean University of ChinaQingdao 266100China Laboratory for Ocean Dynamics and Climate Laoshan LaboratoryQingdao 266237China Key Laboratory of Physical Oceanography Institute for Advanced Ocean StudyFrontiers Science Center for Deep Ocean Multispheres and Earth SystemCollege of Oceanic and Atmospheric SciencesOcean University of ChinaQingdao 266100China Key Laboratory of Physical Oceanography–Institute for Advanced Ocean Studies Ocean University of ChinaLaoshan LaboratoryQingdao 266100China Commonwealth Scientific and Industrial Research Organisation Marine and Atmospheric Research Aspendale Victoria 3195Australia State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China Department of Earth System Science University of CaliforniaIrvine CA 92697USA College of Oceanic and Atmospheric Sciences Ocean University of ChinaQingdao 266100China Institute for Environmental and Climate Research Jinan UniversityGuangzhou 510000China

世界卫生组织2021年提出了新的臭氧标准,不仅加严了原有的短期暴露标准,还增加了暖季峰值的长期暴露指标.2019年秋季我国发生了大范围臭氧污染事件,特别是珠三角地区臭氧浓度异常增加最为突出,导致其暖季峰值超标,并且2019年长时间臭氧... 详细信息

世界卫生组织2021年提出了新的臭氧标准,不仅加严了原有的短期暴露标准,还增加了暖季峰值的长期暴露指标.2019年秋季我国发生了大范围臭氧污染事件,特别是珠三角地区臭氧浓度异常增加最为突出,导致其暖季峰值超标,并且2019年长时间臭氧污染事件增幅更大.本文发现地面太阳辐射与臭氧年际变化相关性远高于其他气象因子,即使在温度较低时,较强的太阳辐射依然可促进高臭氧浓度累积.数值模式显示强太阳辐射驱动天然源大幅增加,不仅促进臭氧浓度升高,更重要的是,对于长时间臭氧污染事件频率增加大于短期污染事件,从而大大促进臭氧超标天数的增加.结合高分辨率地球系统模式和多模式比较计划,一致揭示在全球变暖下中国东部、美国东南部、欧洲各国,未来地面太阳辐射显著增加.通过将秋季地面太阳辐射日异常标准化,构建了臭氧气象指数,可有效揭示高臭氧浓度,阐明在北半球多个易发生臭氧污染区域,高臭氧气象指数天气发生频率显著增加,即利于高臭氧污染发生的气象条件在全球变暖下可能会更加频繁地发生.

关键词：臭氧浓度全球变暖天然源美国东南部气象指数臭氧污染气象条件短期暴露

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An Effective kHz Repetition Rate Single Longitudinal Mode Q-switched Nd:YVO4 Laser Based on a Volume Bragg Grating 15

An Effective kHz Repetition Rate Single Longitudinal Mode Q-...

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15th International Conference on Information Optics and Photonics, CIOP 2024

作者： Wang, Yaqi Lu, Tingting Ma, Jian Zhang, Junxuan Zhu, Xiaolei Zhou, Tianhua Fan, Tingwei Key Laboratory of Space Laser Communication and Detection Technology Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences No. 390 Qinghe Road Jiading District Shanghai201800 China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences No. 80 Zhongguancun East Road Haidian District Beijing100049 China Aerospace Laser Technology and System Department Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences No. 390 Qinghe Road Jiading District Shanghai201800 China Wangzhijiang Innovation Center for Laser Aerospace Laser Technology and System Department Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences Shanghai201800 China

ISBN: (数字)9781510686175

ISBN: (纸本)9781510686168

In this paper, we demonstrated a high slope efficiency, low threshold, single-longitudinal mode (SLM) Q-switched Nd:YVO4 laser emitting at 1064 nm. Using a reflecting Bragg grating (RBG) as the output coupler, we realized a stable SLM operation of which maximum output power was 1.01 W at 1 kHz repetition rate. The output linewidth was less than 4 pm, and the pulse duration was around 3.2 ns. An opto-optic conversion efficiency of 17.1% and a slope efficiency of up to 24.4% were achieved. The laser beam quality factor M2 was 1.21 for horizontal direction and 1.13 for vertical direction, respectively. © 2024 SPIE.

关键词： Pulse repetition rate

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Mapping anthropogenic emissions in China at 1 km spatial resolution and its application in air quality modeling

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science Bulletin 2021年第6期66卷 612-620,M0004页

作者： Bo Zheng Jing Cheng Guannan Geng Xin Wang Meng Li Qinren Shi Ji Qi Yu Lei Qiang Zhang Kebin He Institute of Environment and Ecology Tsinghua Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System ScienceTsinghua UniversityBeijing 100084China State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China China National Environmental Monitoring Center Beijing 100012China Center for Environmental Risk and Damage Assessment Chinese Academy of Environmental PlanningBeijing 100012China Center for Regional Air Quality Simulation and Control Chinese Academy of Environmental PlanningBeijing 100012China

New challenges are emerging in fine-scale air quality modeling in China due to a lack of high-resolution emission ***,only a few emission sources have accurate geographic locations(point sources),while a large part of sources,including industrial plants,are estimated as provincial totals(area sources)and spatially disaggregated onto grid cells based on proxies;this approach is reasonable to some extent but is highly questionable at fine spatial ***,we compile a new comprehensive point source database that includes nearly 100,000 industrial facilities in *** couple it with the frame of Multi-resolution Emission Inventory for China(MEIC),estimate point source emissions,combine point and area sources,and finally map China’s anthropogenic emissions of 2013 at the spatial resolution of 30’’*30’’(~1 km).Consequently,the percentages of point source emissions in the total emissions increase from less than 30%in the MEIC up to a maximum of 84%for SO_(2)in *** new point source-based emission maps show the uncoupled distribution of emissions and populations in space at fine spatial scales,however,such a pattern cannot be reproduced by any spatial proxy used in the conventional emissions *** new accurate high-resolution emission mapping approach reduces the modeled biases of air pollutant concentrations in the densely populated areas compared to the raw MEIC inventory,thus improving the assessment of population exposure.

关键词： Anthropogenic emission inventory High-resolution mapping Air quality modeling

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Adaptive extended Kalman filter and point ahead angle prediction in the detection of gravitational waves in space

arXiv

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arXiv 2024年

作者： Yang, Jinke Xie, Yong Tang, Wenlin Liang, Xindong Zhang, Liang Cui, Zhao Wang, Xue Li, Haojie Jia, Jianjun Lau, Yun Kau Shanghai Institute of Technical Physics Chinese Academy of Sciences Shanghai200083 China University of Chinese Academy of Sciences Beijing100049 China Key Laboratory of Electronics and Information Technology for Space System National Space Science Center Chinese Academy of Sciences Beijing100190 China Hangzhou Institute for Advanced Study UCAS Hangzhou310024 China Institute of Applied Mathematics Morningside Center of Mathematics LSSC Academy of Mathematics and System Science Chinese Academy of Sciences 55 Zhongguancun Donglu Beijing100190 China

In the detection of gravitational waves in space, during the science phase of the mission, the point ahead angle mechanism (PAAM) serves to steer a laser beam to compensate for the angle generated by the relative motion of the two spacecrafts (SCs) during the approximately 10 seconds of flight time a laser beam will take from one SC to reach a distant SC of three million kilometers away. The common practice for pointing stability control of a laser beam is to first do a coarse tracking by the PAAM to steer a laser beam to compensate for the relative motion between two SCs, to be followed by a fine pointing stability control. In the present work, by exploiting the near-circular orbit structure of individual SC in the triangular constellation, the feasibility of inserting an adaptive Kalman filter (AEKF) into the PAAM control loop is investigated. By adopting a colored measurement noise model that closely resembles the prospective on orbit situation, numerical simulation suggests that the dynamic range of the PAAM may be reduced to the level of nanoradians using the prediction of the pointing head angle (PAA) by the AEKF. This will cut down on the TTL coupling noise and the position noise budget allocated to the PAAM. This in turn reduces the dynamic range of the fine pointing control and leaves room to improve its accuracy, thereby offers the prospect of reduction of the position noise budget allocated to the laser pointing instability as a whole. Copyright © 2024, The Authors. All rights reserved.

关键词： Laser beams

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Attributed Scattering center Extraction With Improved Orthogonal Matching Pursuit

Attributed Scattering Center Extraction With Improved Orthog...

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2022 International Symposium on Antennas and Propagation (ISAP)

作者： Guopeng Peng Chunheng Liu Jiahui Wu Yuxiang Zhou Xing Wang Jinyong Hou Institute of System Engineering Beijing China National Key Laboratory of Science and Technology on Antennas and Microwaves Xidian University Xi’an Shaanxi China Key Laboratory of Electronic Information Countermeasure and Simulation Technology Ministry of Education Xidian University Xi’an Shaanxi China

ISBN: (数字)9781665479622

ISBN: (纸本)9781665479639

The attributed scattering center extraction is aimed to solve a high-dimensional, and highly nonlinear problem, which generates high complexity and memory requirements. To alleviate this difficulty, this paper proposes an attributed scattering center extraction method with improved orthogonal matching pursuit (OMP). Local optimization orthogonal matching pursuit (LOOMP) and alternative optimization are utilized to estimate parameters and reduce the dictionary dimension. Experimental results show that the proposed method outperforms the existing frequency-domain method in terms of runtime and memory requirements.

关键词： Dictionaries Runtime Frequency-domain analysis Memory management Matching pursuit algorithms Scattering Complexity theory

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Separated Active Site and Reaction space for Multi-Pollutant Elimination Significantly Enhancing Low Toxic Product Selectivity

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Advanced Functional Materials 2023年第48期33卷

作者： Wei, Lu Liu, Yuxi Cui, Suping Wang, Can Hsi, Hsing-Cheng Duan, Erhong Peng, Yue Dai, Hongxing Guo, Guangsheng Deng, Jiguang Key Laboratory of Beijing on Regional Air Pollution Control Beijing Key Laboratory for Green Catalysis and Separation Center of Excellence for Environmental Safety and Biological Effects Beijing University of Technology Beijing100124 China Faculty of Materials and Manufacturing Key Laboratory of Advanced Functional Materials Ministry of Education Beijing University of Technology Beijing100124 China School of Environmental Science and Engineering Tianjin University Tianjin300350 China Graduate Institute of Environmental Engineering National Taiwan University Taipei10617 Taiwan School of Environmental Science and Engineering Hebei University of Science and Technology Hebei050018 China State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing100084 China

It is possible to remove volatile organic compounds containing chlorine (CVOCs, such as chlorobenzene) in a single device designed for selective catalytic reduction of NOx with NH3 for the industries containing CVOCs and NOx. Breaking the efficiency-selectivity trade-off in chlorobenzene oxidation remains a major challenge due to the conjugation of halogen atoms with the benzene ring and the reducing nature of NH3. A stepwise synthesis strategy is demontrated to disperse dual Ru/Cu Lewis acid sites outside and inside the zeolite channel. Under the confinement of zeolite, the Ru4+ Lewis acid site on the external surface of the zeolite promotes chlorobenzene oxidation by weakening the p-π conjugate structure of Cl and benzene ring, while the Cu2+ Lewis acid site within the internal channel converts NOx and NH3 to N2. The mutual interference between catalytic oxidation and reduction is successfully avoided. Therefore, the low toxic CO2 and HCl selectivity experience a considerable increase from 21% to 86%, and from 51% to 94% with 91% conversion of chlorobenzene, while maintaining excellent elimination performance for NO (with N2 selectivity exceeding 90%). The incorporation of separated active sites and reaction spaces into the design may offer potentials for other energy and environmental applications. © 2023 Wiley-VCH GmbH.

关键词： Zeolites

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Cross-stacked super-aligned carbon nanotube/activated carbon composite electrodes for efficient water purification via capacitive deionization enhanced ultrafiltration

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Frontiers of Environmental science & Engineering 2020年第6期14卷 181-190页

作者： Min Li Shuai Liang Yang Wu Meiyue Yang Xia Huang Beijing Key Laboratory for Source Control Technology of Water Pollution College of Environmental Science and EngineeringBeijing Forestry UniversityBeijing 100083China Department of Mechanical Engineering and Tsinghua Foxconn Nanotechnology Research Center Tsinghua UniversityBeijing 100084China State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China

The practical application of the capacitive deionization(CDI)enhanced ultrafiltration(CUF)technology is hampered due to low performance of *** current study demonstrated a novel super-aligned carbon nanotube(SACNT)/activated carbon(AC)composite electrode,which was prepared through coating AC on a cross-stacked SACNT *** desalination capability and water purification performance of the prepared electrode were systematically investigated at different applied voltages(0.8-1.2 V)with a CDI system and a CUF system,*** the CDI tests,as compared with 5ie control AC electrode,the SACNT/AC electrode achieved an approximately 100%increase in both maximum salt adsorption capacity and average salt adsorption rate under all the applied voltage conditions,demonstrating a superior desalination ***,a conspicuous increase by an average of-26%in charge efficiency was also achieved at all the *** the CUF tests,as compared with the control run at 0 V,the treatment runs at 0.8,1.0,and 1.2 V achieved a 2.40-fold,2.08-fold,and 2.43-fold reduction in membrane fouling(calculated according to the final transmembrane pressure(TMP)data at the end of every purification stage),*** average TMP increasing rates at 0.8,1.0,and 1.2 V were also roughly two times smaller than that at 0 V,indicating a dramatical reduction of membrane *** SACNT/AC electrode also maintained its superior desalination capability in the CUF process,resulting in an overall improved water purification efficiency.

关键词： Carbon nanotube Super aligned Conductive membrane Capacitive deionization Ultrafiltration Desalination

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