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Design,modeling and experimental investigation of a novel solar sail with high area-to-mass ratios for efficient solar sailing

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Chinese Journal of Aeronautics 2024年第10期37卷 234-248页

作者： Zhongjing REN chengyang LI Ke WU Ziran WANG Haipeng WANG Peng YAN Key Laboratory of High-efficiency and Clean Mechanical Manufacture(Ministry of Education) School of Mechanical EngineeringShandong UniversityJinan 250061China China Manned Space Agency Beijing 100071China

Solar sailing is a promising propellant-free approach to propelling spacecraft in ***,the propelling efficiency of conventional solar sail spacecraft is limited by their areato-mass *** paper proposes a novel design of micro solar sails with area-to-mass ratios above 100 m2.kg for next-generation chip-scale *** thin films developed by Microelectromechanical Systems(MEMS)technologies were patterned into grid microstructures,and theoretical analysis of a sail prototype was *** electro-thermal and thermo-mechanical models of the solar sail in geospace were established by taking effects of Joule heating,solar radiation,and thermal re-emission into consideration,enabling rapid prediction of its threedimensional(3-D)reconfiguration from the as-released two-dimensional(2.D)*** of the ChipSail’s acceleration arising from the sail’s morphing was also analytically *** and characterization of the sail prototype made of multiple Al/Ni50Ti50 bilayer beams were ***-situ SEM imaging of the sail prototype in vacuum chamber witnessed an active and continuous 3-D reconfiguration under Joule heating,and over 90deformation was detected by applying a DC voltage of 0.078 *** and experimental work on the solar sail with at least 10 times higher area-to-mass ratios than conventional ones will lay a solid foundation for efficient solar sailing.

关键词： Solar sails Solar sailing High area-to-mass ratios Solar radiation pressure ChipSail

Vulnerability assessment of UAV engine to laser based on improved shotline method

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Defence Technology（防务技术） 2024年第3期33卷 588-600页

作者： Le Liu chengyang Xu Changbin Zheng Sheng Cai Chunrui Wang Jin Guo Changchun Institute of Optics Fine Mechanics and PhysicsChinese Academy of SciencesChangchun 130033China University of Chinese Academy of Sciences Beijing 100049China

Laser anti-drone technology is entering the sequence of actual combat,and it is necessary to consider the vulnerability of typical functional parts of *** the concept of"vulnerability"was proposed,a variety of analysis programs for battlefield targets to traditional weapons have been developed,but a comprehensive assessment methodology for targets'vulnerability to laser is still *** on the shotline method,this paper proposes a method that equates laser beam to shotline array,an efficient vulnerability analysis program of target to laser is established by this method,and the program includes the circuit board and the wire into the vulnerability analysis category,which improves the precision of the vulnerability *** the UAV engine part as the target of vulnerability analysis,combine with the"life-death unit method"to calculate the laser penetration rate of various materials of the UAV,and the influence of laser weapon system parameters and striking orientation on the killing probability is quantified after introducing the penetration rate into the vulnerability analysis *** quantitative analysis method proposed in this paper has certain general expansibility,which can provide a fresh idea for the vulnerability analysis of other targets to laser.

关键词： Laser weapon Laser damage Vulnerability UAV Engine Killing probability

Understanding adversarial attacks on observations in deep reinforcement learning

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Science China(Information Sciences) 2024年第5期67卷 69-83页

作者： You QIAOBEN chengyang YING Xinning ZHOU Hang SU Jun ZHU Bo ZHANG Department of Computer Science and Technology Beijing National Research Center for Information Science and Technology Tsinghua-Bosch Joint Center for Machine Learning Institute for Artificial Intelligence Tsinghua University Peng Cheng Laboratory

Deep reinforcement learning models are vulnerable to adversarial attacks that can decrease the cumulative expected reward of a victim by manipulating its observations. Despite the efficiency of previous optimization-based methods for generating adversarial noise in supervised learning, such methods might not achieve the lowest cumulative reward since they do not generally explore the environmental ***, a framework is provided to better understand the existing methods by reformulating the problem of adversarial attacks on reinforcement learning in the function space. The reformulation approach adopted herein generates an optimal adversary in the function space of targeted attacks, repelling them via a generic two-stage framework. In the first stage, a deceptive policy is trained by hacking the environment and discovering a set of trajectories routing to the lowest reward or the worst-case performance. Next, the adversary misleads the victim to imitate the deceptive policy by perturbing the observations. Compared to existing approaches, it is theoretically shown that our adversary is strong under an appropriate noise level. Extensive experiments demonstrate the superiority of the proposed method in terms of efficiency and effectiveness, achieving state-of-the-art performance in both Atari and MuJoCo environments.

关键词： deep learning reinforcement learning adversarial robustness adversarial attack

Attack based on data: a novel perspective to attack sensitive points directly

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Cybersecurity 2024年第3期7卷 111-123页

作者： Yuyao Ge Zhongguo Yang Lizhe Chen Yiming Wang chengyang Li School of Information Science and Technology North China University of TechnologyBeijingChina Bejing Key Laboratory on Integration and Analysis of Large-Scale Stream Data North China University of TechnologyBeijingChina School of Computer Science Peking UniversityBeijingChina

Adversarial attack for time-series classification model is widely explored and many attack methods are *** there is not a method of attack based on the data *** this paper,we innovatively proposed a black-box sparse attack method based on data *** method directly attack the sensitive points in the time-series data accord-ing to statistical features extract from the *** frst,we have validated the transferability of sensitive points among DNNs with different ***,we use the statistical features extract from the dataset and the sensi-tive rate of each point as the training set to train the predictive ***,predicting the sensitive rate of test set by predictive ***,perturbing according to the sensitive *** attack is limited by constraining the LO norm to achieve one-point *** conduct experiments on several datasets to validate the effectiveness of this method.

关键词： Black-box adversarial attack Time series classification Data mining

What factors control plant height?

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Journal of Integrative Agriculture 2024年第6期23卷 1803-1824页

作者： Li Miao Xiangyu Wang Chao Yu chengyang Ye Yanyan Yan Huasen Wang College of Horticulture Qingdao Agricultural UniversityQingdao 266109China Key Laboratory for Quality and Safety Control of Subtropical Fruits and Vegetables College of Horticulture ScienceZhejiang Agriculture and Forestry UniversityHangzhou 311300China

Plant height(PH)is one of the most important components of the plant ideotype,and it affects plant biomass,yield,lodging resistance,and the ability to use mechanized *** many complex pathways controlling plant growth and development remain poorly understood,we are still unable to obtain the most ideal plants solely through breeding *** can be influenced by genotype,plant hormonal regulation,environmental conditions,and interactions with other ***,we comprehensively review the factors influencing PH,including the regulation of PH-related developmental processes,the genetics and QTLs contributing to PH,and the hormone-regulated molecular mechanisms for ***,the symbiotic influence of grafting on PH is discussed,focusing on the molecular regulation of gene expression and ***,we propose strategies for applying recent findings to breeding for better PH,highlight some knowledge gaps,and suggest potential directions for future studies.

关键词： dwarfism plant hormones interaction grafting QTLs phenotyping

Variability of urban fractional vegetation cover and its driving factors in 32. cities in China

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Science China Earth Sciences 2024年第2期67卷 466-482页

作者： Fei FENG Xin YANG Baoquan JIA Xiaoting LI Xianwen LI chengyang XU Kaicun WANG Research Centre of Urban Forestry Key Laboratory for Silviculture and Forest Ecosystem of State Forestry and Grassland AdministrationBeijing Forestry UniversityBeijing100083China State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal UniversityBeijing100875China Research Institute of Forestry Chinese Academy of ForestryBeijing100091China School of Architecture Tsinghua UniversityBeijing100084China College of Urban and Environmental Sciences Sino-French Institute for Earth System ScienceInstitute of Carbon NeutralityPeking UniversityBeijing100871China

Urban green space promotes the health of urban residents,enhances urban ecosystem biodiversity,mitigates environmental pollution,and attenuates urban heat island ***,urban vegetation cover is highly heterogeneous and difficult to *** this study,the variation of urban fractional vegetation cover(FVC)in 32. cities in China from 1990 to2.2. was quantified based on Landsat satellite data at a 30-m *** was found that from 1990 to 2.05,due to increases in building density and impervious surfaces in cities,the national mean urban vegetation cover decreased from 0.38 to ***2.05,urban vegetation cover began to reverse,reaching 0.45 in *** increasing trend was most pronounced in newly built urban *** decrease in average urban vegetation cover before 2.05 was mainly due to the expansion of low vegetation cover areas,while the increase in urban vegetation cover after 2.05 manifested as the expansion of high vegetation cover *** reversal in the trend of urban vegetation cover change after 2.04 is related to the gradual implementation of national policies requiring increased urban green space *** urban gross domestic product(GDP)showed the highest correlation with changes in urban vegetation *** large and medium-sized cities,the top three factors influencing vegetation cover were GDP,urban population,and ***,for cities in arid/semi-arid regions,changes in vegetation cover were more sensitive to climatic factors(such as precipitation).Although the urban vegetation cover in China has substantially increased in recent years,the urban green space in small-sized cities and in the old urban districts of large-sized cities still have room to improve.

关键词： Urban vegetation Urban vegetation cover Urbanization Remote sensing

Progress of photocatalytic COreduction toward multi-carbon products

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Science China Chemistry 2024年

作者： Jiaojiao Fang chengyang Zhu Huiling Hu Jiaqi Li Licheng Li Haiyan Zhu Junjie Mao Key Laboratory of Functional Molecular Solids Ministry of Education College of Chemistry and Materials ScienceAnhui Normal University

The photocatalytic CO2.eduction reaction （CO2.R） represents a promising solution to alleviate environmental and energy issues stemming from CO2.missions while simultaneously enabling the production of high-value multi-carbon ***,the efficient generation of multi-carbon products remains challenging due to high kinetic barriers,sluggish C–C coupling processes,and intricate reaction *** review provides a comprehensive overview of the latest advancements in synthesizing C2.products through CO2.hotoreduction,highlighting the crucial role of active site design and the C–C coupling ***,we emphasize the correlation between the structure of active sites and the key intermediates of C–C coupling,which is fundamental for achieving deep photoconversion of ***,we offer a glimpse into future challenges and prospects,outlining potential directions for the development of CO2.to-multicarbon photoconversion,aiming to contribute novel insights to this exciting field.

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劳动形态的数字化变革及教劳结合的再认识

国家教育行政学院学报 2024年第6期318卷 72-82页

作者：类成阳华中科技大学湖北武汉430074

随着劳动教育进入党的教育方针并取得与德智体美“四育”同等的地位,教劳结合这一带有鲜亮中国底色的教育原则在新时代焕发新生机,迎来了助推新变革的契机。劳动形态的数字化变革使劳动泛化,非物质和非生产劳动逐渐凸显;使劳动融合化,... 详细信息

随着劳动教育进入党的教育方针并取得与德智体美“四育”同等的地位,教劳结合这一带有鲜亮中国底色的教育原则在新时代焕发新生机,迎来了助推新变革的契机。劳动形态的数字化变革使劳动泛化,非物质和非生产劳动逐渐凸显;使劳动融合化,数字劳动这类复合型劳动日益普遍;使劳动模糊化,劳动和非劳动的界限愈发游移。为此,教劳结合应基于马克思主义经典理论的立场,在数字时代谋求提升与非物质和非生产劳动的关联度、注重科技教育以涵盖数字劳动等新劳动形态、着力建构数字时代的技术观以巩固人的主体性,适应劳动形态的数字化变革。最终,以数字技术为中介,推动人转向以知识生产为中心的间接劳动并助力学习型社会在数字时代的建构,实现劳动形态数字化变革下的教劳结合。

关键词：劳动形态数字化变革教劳结合

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农村教育与乡村产业振兴协调发展研究

现代经济探讨 2024年第5期 98-107页

作者：戎乘阳西南大学教育学部重庆400715

农村教育与乡村产业振兴协调发展是新时代农村社会进步的现实要求。在探讨农村教育与乡村产业振兴协调发展机理的基础上,基于2.13年至2.2.年面板数据,验证农村教育与乡村产业振兴之间的互动效应,测算农村教育与乡村产业振兴协调发展程度... 详细信息

农村教育与乡村产业振兴协调发展是新时代农村社会进步的现实要求。在探讨农村教育与乡村产业振兴协调发展机理的基础上,基于2.13年至2.2.年面板数据,验证农村教育与乡村产业振兴之间的互动效应,测算农村教育与乡村产业振兴协调发展程度,分析农村教育与乡村产业振兴协调发展趋势和首要障碍因子。研究发现:中国农村教育和乡村产业振兴之间存在互动效应,2.13年以来协调发展程度逐年增高,已经顺利进入中度协调时期。东部地区协调发展程度始终领先但出现瓶颈,西部地区协调发展程度不再落后且增速较高,中部地区协调发展程度逐渐落后但发展潜力大。当前协调发展的首要障碍因子是农业科技人员占第一产业人员的比例。据此,应该构建产教融合的社会支持机制,制定强针对性的专项发展策略,提高农村人力资本的转化效率。

关键词：农村教育乡村产业振兴协调发展人力资本