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Cable-driven legged landing gear for unmanned helicopter:Prototype design,optimization and performance assessment

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Science China(Technological Sciences) 2024年第4期67卷 1196-1214页

作者： TIAN BaoLin GAO HaiBo yu HaiTao shan HaoMin hou JunChen yu HongYing DENG ZongQuan State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin 150001China China Academy of Aerospace Science and Innovation Beijing 100048China

Unmanned helicopters equipped with adaptive landing gear will dramatically extend their application especially in dealing with challenging *** study presents a novel cable-driven legged landing gear(CLG)with differential transmission for unmanned helicopters in complex landing *** obtain the preferred configuration of the legged mechanism,a multi-objective optimization framework for the CLG is constructed by concurrently considering terrain adaptability,landing stability and reasonable linkage of internal *** non-dominated sorting genetic algorithmⅡis employed to numerically acquire the optimal scale parameters that guide the mechanical design of the *** unmanned helicopter prototype equipped with the devised CLG is developed with key performance *** results show that the devised CLG can provide energy-efficient support over uneven terrains(totally driven torque demand less than 0.1 N m)in quasi-static landing tests,and favorable terrain adaptability(posture fluctuation of the fuselage less than±1°)in unknown slope landing *** exhibited merits give the proposed CLG the potential to enhance the landing performance of future aircraft in extreme environments.

关键词： unmanned helicopter adaptive landing gear experimental verification

Dual-Confined Bead-Like CoSe_(2)@NC@NCNFs Bifunctional Catalyst Boosting Rechargeable Zinc-Air Batteries

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Chinese Journal of Chemistry 2024年第4期42卷 397-405页

作者： Kuixing Ding Jiugang Hu Liming Zhao Huanan yu shan Cai Yi Yang Jun Tan Hongshuai hou Xiaobo Ji College of Chemistry and Chemical Engineering Central South UniversityChangshaHunan410083 China College of Materials and Chemistry China Jiliang UniversityHangzhouZhejiang310018 China College of Standardization China Jiliang UniversityHangzhouZhejiang310018 China

Rationally developing efficient and durable bifunctional catalysts toward oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)is critical for rechargeable zinc-air batteries(ZABs).Herein,a bead-like CoSe_(2)@NC@NCNFs bifunctional catalyst was designed and fabricated by confining cubic CoSe_(2)nanoparticles to three-dimensional(3D)porous MOFs-derived nitrogen-doped carbon(NC)and one-dimensional(1D)N-doped carbon nanofibers(NCNFs)through a facile encapsulate *** 1D/3D continuous network structure contributes to the improvement of specific surface area and electronic conductivity,while the strong synergistic effect between CoSe_(2)sites and Co-Nx-C sites can effectively enhance electron/mass transfer and reduce the diffusion *** as-constructed CoSe_(2)@NC@NCNFs catalyst exhibits high catalytic activity and stability toward ORR/OER with a high half-wave potential of 0.80 V(***)in ORR and a low overpotential of 280 mV at 10 mA·cm^(−2)in *** encouragingly,the rechargeable ZABs with CoSe_(2)@NC@NCNFs cathode deliver high peak power densities(126.8 mW·cm^(−2)),large specific capacities(763.1 mA·h·g^(−1)),and robust charge-discharge cycling stability over 240 *** study provides a facile strategy for designing efficient bifunctional catalysts for rechargeable energy conversion applications.

关键词： Dual-confined Electrospinning Cobalt selenide Bifunctional catalysts Rechargeable zinc-air batteries

Low Resource Chinese Geological Text Named Entity Recognition Based on Prompt Learning

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Journal of Earth Science 2024年第3期35卷 1035-1043页

作者： Hang He Chao Ma shan Ye Wenqiang Tang yuxuan Zhou Zhen yu Jiaxin Yi Li hou Mingcai hou State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Institute of Sedimentary GeologyCollege of Computer Science and Cyber SecurityChengdu University of TechnologyChengdu 610059China Key Laboratory of Deep-Time Geography and Environment Reconstruction and Applications of Ministry of Natural Resources Chengdu University of TechnologyChengdu 610059China School of Information Engineering China University of Geosciences(Beijing)Beijing 100083China

Geological reports are a significant accomplishment for geologists involved in geological investigations and scientific research as they contain rich data and textual *** the rapid development of science and technology,a large number of textual reports have accumulated in the field of ***,many non-hot topics and non-English speaking regions are neglected in mainstream geoscience databases for geological information mining,making it more challenging for some researchers to extract necessary information from these *** Language Processing(NLP)has obvious advantages in processing large amounts of textual *** objective of this paper is to identify geological named entities from Chinese geological texts using NLP *** propose the RoBERTa-Prompt-Tuning-NER method,which leverages the concept of Prompt Learning and requires only a small amount of annotated data to train superior models for recognizing geological named entities in low-resource dataset *** RoBERTa layer captures context-based information and longer-distance dependencies through dynamic word ***,we conducted experiments on the constructed Geological Named Entity Recognition(GNER)*** experimental results show that the proposed model achieves the highest F1 score of 80.64%among the four baseline algorithms,demonstrating the reliability and robustness of using the model for Named Entity Recognition of geological texts.

关键词： Prompt Learning Named Entity Recognition(NER) low resource geological text text information mining big data geology.

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Small holes,big impact:Stomata in plant–pathogen–climate epic trifecta

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Molecular Plant 2024年第1期17卷 26-49页

作者： Shuguo hou Olivier Rodrigues Zunyong Liu Libo shan Ping He Peking University Institute of Advanced Agricultural Sciences Shandong Laboratory of Advanced Agriculture Sciences in WeifangWeifangShandong 261325China School of Municipal&Environmental Engineering Shandong Jianzhu UniversityJinanShandong 250101China Unitéde Recherche Physiologie Pathologie et Génétique VégétalesUniversitéde Toulouse Midi-PyrénéesINP-PURPAN31076 ToulouseFrance Department of Molecular Cellularand Developmental BiologyUniversity of MichiganAnn ArborMI 48109USA

The regulation of stomatal aperture opening and closure represents an evolutionary battle between plants and pathogens,characterized by adaptive strategies that influence both plant resistance and pathogen *** ongoing climate change introduces further complexity,affecting pathogen invasion and host *** review delves into recent advances on our understanding of the mechanisms governing immunity-related stomatal movement and patterning with an emphasis on the regulation of stomatal opening and closure dynamics by pathogen patterns and host *** addition,the review explores how climate changes impact plant–pathogen interactions by modulating stomatal *** light of the pressing challenges associated with food security and the unpredictable nature of climate changes,future research in this field,which includes the investigation of spatiotemporal regulation and engineering of stomatal immunity,emerges as a promising avenue for enhancing crop resilience and contributing to climate control strategies.

关键词： stomatal movement stomatal patterning plant resistance pathogen virulence apoplastic immunity and climate change

Heat Transfer Characteristics of a Microchannel Heat Sink with Highly-Dense Micro-Jet Arrays

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Journal of Thermal Science 2024年第3期33卷 1148-1160页

作者： ZHANG yu CHEN Xiaoyan MIAO Lin CHEN Liang hou yu State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an710049China Beijing Aerospace Technology Institute Beijing100083China

This paper proposed a new structure of highly-dense micro-jet arrays for hybrid jet-impingement/microchannel heat sinks(~120 jet per cm^(2) with jet width of 0.35 mm).Parametric study is performed to investigate the influence of structure and flow parameters on the convective heat transfer of water jet cooling in confined *** simulation results show that the optimal jet width,jet spacing and impingement distance are around 0.2 mm,0.2 mm and 0.3 mm,respectively,which can achieve a low thermal resistance as well as a relatively low pressure *** analysis of the heat transfer pathways shows that the micro-fin jet structures can extend the impinging heat transfer area and conduct a considerable proportion of heat,which can reach up to 38.9%with the Reynolds number ranging from 797.1 to *** heat transfer characteristics in the heat sink will shift from impingement dominated heat transfer to the channel-convection dominated heat transfer as the jet impingement distance increases.A correlation is proposed to predict the average Nusselt number on the stagnation area for the heat sink with different structure parameters,and the deviations of predictions from the numerical results are less than 10%.

关键词： hybrid heat sink impingement microchannel thermal management high heat flux

Research on Bast Fiber Extracted from the White Bark of Three Species in the Genus Broussonetia

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Chinese Journal of Polymer Science 2024年第6期42卷 729-738页

作者： shan-shan Jin Si-Nong Wang Yan-Yan Huang Jing-yu Zhang Peng Liu Hui yu Hong-Dong Zhang yu-Liang Yang Institute for Preservation and Conservation of Chinese Ancient Books Fudan University LibraryFudan UniversityShanghai200433China State key laboratory of Molecular Engineering of polymers Department of Macromolecular ScienceFudan UniversityShanghai200433China

Against the backdrop of a global paper resource shortage,there is a growing need to identify fast-growing tree species capable of producing long-lasting *** plant species namely Broussonetia kazinoki,Broussonetia papyrifera and hybrid paper mulberry,belong to the Broussonetia genus,were collected from China to study their white bark suitability for pulp and *** chemical composition revealed that the holocellulose content in Broussonetia kazinoki and Broussonetia papyrifera was more than 80%.The molecular weight distribution of several holocellulose/α-cellulose is observed by GPC,which allows us to better observe the changes of various components on the molecular *** yield,lignin,whiteness,and molecular weight of the pulps obtained by NaOH treatment were *** microscope was used to characterize the fiber length-width ratio and ***,the improvement of the fiber rigidity method based on the Kratky-Porod chain model makes it more theoretical and further reveals the influencing factors of fiber *** study demonstrates the high potentiality of these three species for papermaking applications.

关键词： Broussonetia genus Cellulose Alkaline pulping Kratky-Porod chain model Fiber rigidity

Engineering high-performance dielectric chiral shells with enhanced chiral fields for sensitive chiral biosensor

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Rare Metals 2024年第3期43卷 1197-1206页

作者： Yi-Fan Wang shan-shan Huang Zhen-Dong Dai Shi-Lin Xian Xuan-Nan Wu Fu-Hua Gao Yi-Dong hou College of Physics Sichuan UniversityChengdu610065China Graduate School of Sichuan University Sichuan UniversityChengdu610065China

Chiral metamaterials have been a topic of significant research interest in recent years due to their potential for various applications in nanophotonic devices and chiral ***,the intrinsic Ohmic loss in surface plasmonic resonance has limited their practical use,resulting in large light dissipation and weak chiroptical ***,we report on the development of high-performance dielectric chiral shells(DCS)through a two-step Si deposition process on a self-assembled microsphere *** form DCS sample completely oyercomes the cancelation effect originated from the disorder property of the micro-sphere monolayer in macroscale,and at a wavelength of approximately 710 nm,the measured optimal chiral signal(g-factor)and transmittance can reach up to 0.7 and 0.3,*** strong chiroptical effect comes from the asymmetric circular displacement currents(i.e.,magnetic modes)enabled by the specific shell *** chiral shell geometry,electromagnetic properties,sensor sensitivity of chiral molecules and figure of merit are systematically *** DCSs demonstrate highly sensitive detection of chiral biomolecules owing to their easily accessible geometry and enhanced uniform chiral field.

关键词： Dielectric chiral shells(DCS) Si deposition Magnetic resonance Highly sensitive sensor Chiral field

Capture Efficiency Analysis in the Circular Restricted Three-body Problem

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Research in Astronomy and Astrophysics 2024年第5期24卷 198-210页

作者： yu-Xuan Miao Xi-yun hou Department of Astronomy and Space Science Nanjing UniversityNanjing 210023China Institute of Space Environment and Astrodynamics Nanjing UniversityNanjing 210023China Key Laboratory of Modern Astronomy and Astrophysics Ministry of EducationNanjing 210023China

Temporary capture efficiency is studied in the framework of the circular restricted three-body problem in two ***, a non-uniform distribution of test particles around the secondary's orbit is obtained by fully accounting the secondary's gravitational influence. Second, the capture efficiency is computed based on the non-uniform distribution. Several factors influencing the result are discussed. By studying the capture efficiency in the circular restricted three-body problem of different mass ratios, a power-law relation between the capture efficiency(p) and the mass ratio(μ) is established, which is given by p ≈ 0.27 × μ^(0.53), within the range of 3.0035 ×10^(-6)≤ μ ≤ 3.0034 × 10^(-5). Taking the Sun–Earth system as an example, the influence from the orbit eccentricity of the secondary on the non-uniform distribution and the capture efficiency is studied. Our studies find that the secondary's orbit eccentricity has a negative influence on the capture efficiency.

关键词： methods numerical-celestial mechanics-planets and satellites dynamical evolution and stability

First Digit Distributions of Gamma-Ray Bursts

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Research in Astronomy and Astrophysics 2024年第5期24卷 70-75页

作者： hou-yu Lai Jun-Jie Wei Purple Mountain Observatory Chinese Academy of SciencesNanjing 210023China School of Astronomy and Space Sciences University of Science and Technology of ChinaHefei 230026China

The occurrence of the first significant digits from real world sources is usually not equally distributed,but is consistent with a logarithmic distribution instead,known as Benford’s *** this work,we perform a comprehensive investigation on the first digit distributions of the duration,fluence,and energy flux of gamma-ray bursts (GRBs) for the first *** a complete GRB sample detected by the Fermi satellite,we find that the first digits of the duration and fluence adhere to Benford’s ***,the energy flux shows a significant departure from this law,which may be due to the fact that a considerable part of the energy flux measurements is restricted by lack of spectral *** on the conventional duration classification scheme,we also check if the durations and fluences of long and short GRBs (with duration T_(90)>2 s and T_(90)≤2 s,respectively) obey Benford’s *** find that the fluences of both long and short GRBs still agree with the Benford distribution,but their durations do not follow Benford’s *** results hint that the long–short GRB classification scheme does not directly represent the intrinsic physical classification scheme.

关键词： (stars:)gamma-ray burst general-methods statistical-astronomical databases miscellaneous