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Evidence of guide field magnetic reconnection in flapping current sheets

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Earth and Planetary Physics 2024年第4期8卷 650-658页

作者： yunTian Hou SuPing duan Lei Dai Chi Wang State Key Laboratory of Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China Key Laboratory of Solar Activity and Space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

Based on current sheet flapping motion on 27 August 2018 in the dusk flank magnetotail,as recorded by instruments aboard Magnetospheric Multiscale(MMS)spacecraft,we present the first study of guide field reconnection observed in the flux rope embedded in kink-like flapping current sheets near the dusk-side flank of the *** more common magnetotail reconnections,which are symmetric,these asymmetric small-scale(λ_(i)~650 km)reconnections were found in the highly twisted current sheet when the direction normal to the sheet changes from the Z direction into the y *** unique feature of this unusual reconnection is that the reconnection jets are along the Z direction-different from outflow in the X direction,which is the more usual *** vertical reconnection jet is parallel or antiparallel to the up-and-down motion of the tail’s current *** normalized reconnection rate R is estimated to be~*** results indicate that such asymmetric reconnections can significantly enlarge current sheet flapping,with large oscillation *** letter presents direct evidence of guide field reconnection in a highly twisted current sheet,characterized by enlarged current sheet flapping as a consequence of the reconnection outflow.

关键词： magnetic reconnection magnetotail current sheet

Impact of Media Information on Social Response in Disasters:A Case Study of the Freezing‑Rain and Snowstorm Disasters in Southern China in 2008

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International Journal of Disaster Risk Science 2024年第1期15卷 73-87页

作者： Jia He Wenjing duan yuxuan Zhou yun Su College of Geographic Science and Tourism Xinjiang Normal UniversityUrumqi 830054China Xinjiang Laboratory of Lake Environment and Resources in Arid Zone Urumqi 830054China Faculty of Geographical Science Beijing Normal UniversityBeijing 100875China Key Laboratory of Environmental Change and Natural Disaster Ministry of EducationBeijing Normal UniversityBeijing 100875China

Disaster information content is an objective mapping of disaster situations,social response,and public *** response to emergency is an important mechanism for implementing and guaranteeing emergency management of major natural hazard-related *** how disaster information content affects social response to emergencies is helpful for managing risk communication and efficient disaster *** on the 2008 freezing-rain and snowstorm disasters in southern China,this study used Python to extract 7,857 case-related media reports and applied natural language processing for text *** used three typical cases to identify and analyze disaster media report content and the relationship between these reports and the social response to the *** categories of disaster response-such as prewarning and forecasting,announcements by the authorities,and social mobilization-appeared in the disaster information in the media,along with disaster impact information,that is,real-time disaster *** response information and an appropriate amount of disaster impact information played important roles in prewarning,disaster relief,public opinion guidance,and social stability maintenance and can serve important functions in communicating with all stakeholders of emergency management,assisting or influencing emergency departments or individuals in decision making,and eliminating "information islands." Empathy caused the general public to become "disaster responders" through receiving *** and an excess of negative information may have a perverse amplification effect on public opinion and increase the unpredictability of the disaster situation and the risk of social crisis.

关键词： Emergency management Freezing-rain and snowstorm disasters Media reports on disasters Social response to emergencies China

Patterning single-layer materials by electrical breakdown using atomic force microscopy

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Nanotechnology and Precision Engineering 2024年第1期7卷 71-77页

作者： yajie yang Jiajia Lu yanbo Xie Libing duan School of Physical Science and Technology Northwestern Polytechnical UniversityXi’an 710072China School of Aeronautics and Institute of Extreme Mechanics Northwestern Polytechnical UniversityXi’an 710072China

The development of nanoelectronics and nanotechnologies has been boosted signiﬁcantly by the emergence of 2D materials because of their atomic thickness and peculiar properties,and developing a universal,precise patterning technology for single-layer 2D materials is critical for assembling *** here is a nanomachining technique using electrical breakdown by an AFM tip to fabricate nanopores,nanostrips,and other nanostructures on *** can be achieved by voltage scanning or applying a constant voltage while moving the *** measuring the electrical current,the formation process on single-layer materials was shown *** present results provide evidence of successful pattern fabrication on single-layer MoS2,boron nitride,and graphene,although further conﬁrmation is still *** proposed method holds promise as a general nanomachining technology for the future.

关键词： 2D material Nanopattern AFM Electrical breakdown Lithography

CO_(2) capture by modified clinoptilolite and its regeneration performance

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International Journal of Coal Science & Technology 2024年第2期11卷 81-90页

作者： Bo Jiang Bo Zhang Xuqin duan yi Xing School of Energy and Environmental Engineering University of Science and Technology BeijingBeijing 100083China Beijing Key Laboratory of Resource-Oriented Treatment of Industrial Pollutants University of Science and Technology BeijingBeijing 100083China yangQuan Coal Industry(Group)Co.Ltd. Yangquan 045000China School of Civil and Resource Engineering University of Science and Technology BeijingBeijing 100083China

This study focuses on CO_(2) capture by pressure swing adsorption(PSA),with modified clinoptilolite as the *** clinoptilolite is modified by roasting,by acid pickling,by a combination of acid pickling and roasting,and by ion *** by acid pickling-roasting and by ion exchange are found to give the highest CO_(2) adsorption capacities,of 730 mL/g and 876.7 mL/g,*** is found that regeneration of clinoptilolite by a combination of vacuum desorption and heating enables recovery of as much as 89%of its previous CO_(2) adsorption *** examine the CO_(2) adsorption capacity of clinoptilolite when applied to mixed gas,a simulated coking exhaust containing 12%CO_(2) and 4%O_(2) is used,and it is found that ion exchange modified clinoptilolite achieves a CO_(2) removal efficiency of 92.5%.A BET test reveals that acid pickling-roasting and Na^(+) modification enhance the porosity of clinoptilolite,thereby improving its adsorption *** work demonstrates the feasibility of applying modified clinoptilolite as an effective adsorbent for COO_(2)capture,providing a promising tool for dealing with greenhouse gases.

关键词： Clinoptilolite Carbon dioxide capture Pressure swing adsorption(PSA)

A Novel Multi-Stream Fusion Network for Underwater Image Enhancement

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China Communications 2024年第2期21卷 166-182页

作者： Guijin Tang Lian duan Haitao Zhao Feng Liu Jiangsu Key Laboratory of Image Processing and Image Communication Nanjing University of Posts and TelecommunicationsNanjing 210003China Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and TelecommunicationsNanjing 210003China

Due to the selective absorption of light and the existence of a large number of floating media in sea water, underwater images often suffer from color casts and detail blurs. It is therefore necessary to perform color correction and detail restoration. However,the existing enhancement algorithms cannot achieve the desired results. In order to solve the above problems, this paper proposes a multi-stream feature fusion network. First, an underwater image is preprocessed to obtain potential information from the illumination stream, color stream and structure stream by histogram equalization with contrast limitation, gamma correction and white balance, respectively. Next, these three streams and the original raw stream are sent to the residual blocks to extract the features. The features will be subsequently fused. It can enhance feature representation in underwater images. In the meantime, a composite loss function including three terms is used to ensure the quality of the enhanced image from the three aspects of color balance, structure preservation and image smoothness. Therefore, the enhanced image is more in line with human visual ***, the effectiveness of the proposed method is verified by comparison experiments with many stateof-the-art underwater image enhancement algorithms. Experimental results show that the proposed method provides superior results over them in terms of MSE,PSNR, SSIM, UIQM and UCIQE, and the enhanced images are more similar to their ground truth images.

关键词： image enhancement multi-stream fusion underwater image

Influences of chemical reactions on polysulfide reduction reaction process on promotor surface in Li-S batteries

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Nano Research 2024年第4期17卷 2712-2718页

作者： yufeng Luo Zhenhan Fang Zixin Hong Shaorong duan Haitao Liu Hengcai Wu Qunqing Li yuegang Zhang Shoushan Fan Wenhui duan Jiaping Wang Tsinghua-Foxconn Nanotechnology Research Center Tsinghua UniversityBeijing 100084China Department of Physics Tsinghua UniversityBeijing 100084China Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China Frontier Science Center for Quantum Information Tsinghua UniversityBeijing 100084China

Polar promotors have been proven effective in catalyzing the polysulfide(PS)reduction reaction(PSRR)process in lithium-sulfur(Li-S)***,the promotor surface tends to be poisoned due to the accumulation of insoluble discharging products of lithium disulfide(Li_(2)S_(2))and lithium sulfide(Li_(2)S)during Li-S battery ***,we investigate the detailed PSRR mechanism on the surface of manganese sulfides(MnS)as a representative promoter by performing in-situ Raman mapping *** catalytic ability of MnS enables thorough electrochemical reduction of PSs to Li_(2)S_(2) and Li_(2)S on the MnS *** generated Li_(2)S_(2) and Li_(2)S then adsorb the dissolved PSs via chemical reactions among sulfur species during the subsequent PSRR *** phenomenon mitigates promotor poisoning and continuously improves the reversible ***,the assembled Li-S cell demonstrates excellent electrochemical performance after introducing a conductive interlayer containing a thin piece of carbon nanotube film and MnS promotors.

关键词： promotors polysulfides chemical reactions catalytic ability in-situ Raman measurements

Recent advances in the synthesis and application of N-heterocyclic carbene-based molecular cages

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Science China Chemistry 2024年第5期67卷 1510-1523页

作者： Qiongjie Chai Lixin duan yanzhe Ma Tianheng Hou Tao Tu Shanghai Key Laboratory of Molecular Catalysis and Innovative Materials Department of ChemistryFudan UniversityShanghai 200438China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China

N-Heterocyclic carbene(NHC)-based cages have emerged as a prominent and dynamic research area within the research field of chemistry. Leveraging the distinctive electronic and steric properties of NHC ligands, the design, synthesis, and application of these corresponding cages have garnered substantial scholarly interest. In recent years, we have witnessed the successful fabrication of diverse NHC-based cages through a range of synthetic methodologies, which hold significant potential for applications in molecular recognition and catalysis. In this review, we delve into the foundational synthetic strategies that underlie the creation of NHC-based cages, employing approaches encompassing metal–NHC chelation, coordination assembly,and covalent bonding. Additionally, we compile the diverse applications of these cages within catalytic processes and molecular recognition. Lastly, we shed light on the current limitations of synthesis and outline future trends in the development of NHCbased cages.

关键词： N-heterocyclic carbene molecular cages supramolecular chemistry synthetic strategies applications

Effects of soil crust on the collapsing erosion of colluvial deposits with granite residual soil

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Journal of Mountain Science 2024年第8期21卷 2579-2591页

作者： LIU Weiping ZENG Bohan WANG Tianhuan duan Junyi School of Infrastructure Engineering Nanchang UniversityNanchang 330031China

Collapsing erosion is a unique phenomenon commonly observed on the granite residue hillslopes in the tropical and subtropical regions of southern China,characterized by its abrupt occurrence and significant erosion ***,the impacts of soil crust conditions on the erosion of colluvial deposits with granite residual soils have only been studied to a limited *** address this issue,this study investigates the impacts of three soil crust conditions(i.e.,without crust,10-minute crust,and 20-minute crust)on gully morphology,rainfall infiltration,and runoff and sediment yield during slope erosion of colluvial deposits with granite residues(classified as Acrisols)in yudu County,Ganzhou City,Jiangxi Province,China,using simulated rainfall tests and photographic *** results showed that as the strength of the soil crust increased,the capacity of moisture infiltration and the width and depth of the gully as well as the sediment concentration and yield ratio decreased;at the same time,the runoff ratio *** sediment yield in the without-crust test was found to be 1.24 and 1.43 times higher than that observed in the 10-minute crust and 20-minute crust tests,*** results indicate that soil crusts can effectively prevent slope erosion and moisture infiltration,while providing valuable insights for the management of soil erosion in natural environments.

关键词： Granite residual soil Colluvial deposits Slope erosion Soil crust Sediment yield

Multiplayer Reach-Avoid Differential Games in 3D Space Inspired by Harris'Hawks'Cooperative Hunting Tactics

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Research 2024年第2期2023卷 41-54页

作者： Wanying Ruan Haibin duan yongbin Sun Wanmai yuan Jie Xia State Key Laboratory of Virtual Reality Technology and Systems School of Automation Science and Electrical EngineeringBeihang UniversityBeijingChina Peng Cheng Laboratory ShenzhenChina Information Science Academy of CETC BeijingChina

This paper investigates a multiplayer reach-avoid differential game in 3-dimensional(3D)space,which involves multiple pursuers,multiple evaders,and a designated target *** evaders aim to reach the target region,while the pursuers attempt to guard the target region by capturing the *** class of research holds significant practical ***,the complexity of the problem escalates substantially with the growing number of players,rendering its solution extremely *** this paper,the multiplayer game is divided into many subgames considering the cooperation among pursuers,reducing the computational burden,and obtaining numerically tractable strategies for ***,the Apollonius sphere,a fundamental geometric tool for analyzing the 3D differential game,is formulated,and its properties are *** on this,the optimal interception point for the pursuer to capture the evader is derived and the winning conditions for the pursuer and evader are ***,based on the Apollonius sphere,the optimal state feedback strategies of players are designed,and simultaneously,the optimal one-to-one pairings are ***,the Value function of the multiplayer reach-avoid differential game is explicitly given and is proved to satisfy Hamilton-Jacobi-Isaacs(HJI)***,the matching algorithm for the case with pursuers outnumbered evaders is provided through constructing a weighted bipartite graph,and the cooperative tactics for multiple pursuers are proposed,inspired by the Harris'Hawks intelligent cooperative hunting ***,numerical simulations are conducted to illustrate the effectiveness of the theoretical results for both cases where the number of adversary players is equal and unequal between the 2 groups.

关键词： holds satisfy rendering