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A 3D-printed microhemispherical shell resonator with electrostatic tuning for a Coriolis vibratory gyroscope

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Microsystems & Nanoengineering 2024年第2期10卷 25-35页

作者： Baoyin Hou Ye Zhu Chaofan he Weidong Wang Zhi Ding Wen he yong he Lufeng Che College of Information Science and Electronic Engineering Zhejiang UniversityHangzhou310027China Center for Microelectronics Shaoxing InstituteZhejiang UniversityShaoxing312035China State key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou310058China School of Mechanical Engineering Zhejiang UniversityHangzhou310058China

The emergence of microhemispherical resonant gyroscopes,which integrate the advantages of exceptional stability and long lifetime with miniaturization,has afforded new possibilities for the development of whole-angle ***,existing methods used for manufacturing microhemispherical resonant gyroscopes based on MEMS technology face the primary drawback of intricate and costly ***,we report the design,fabrication,and characterization of the first 3D-printable microhemispherical shell resonator for a Coriolis vibrating *** remarkably achieve fabrication in just two steps bypassing the dozen or so steps required in traditional *** utilizing the intricate shaping capability and ultrahigh precision offered by projection microstereolithography,we fabricate 3D high-aspect-ratio resonant structures and controllable capacitive air gaps,both of which are extremely difficult to obtain via MEMS *** addition,the resonance frequency of the fabricated resonators can be tuned by electrostatic forces,and the fabricated resonators exhibit a higher quality factor in air than do typical MEMS microhemispherical *** work demonstrates the feasibility of rapidly batch-manufacturing microhemispherical shell resonators,paving the way for the development of microhemispherical resonator gyroscopes for portable inertial ***,this particular design concept could be further applied to increase uptake of resonator tools in the MEMS community.

关键词： resonator tuning electrostatic

Projecting Wintertime Newly Formed Arctic Sea Ice through Weighting CMIP6 Model Performance and Independence

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Advances in Atmospheric Sciences 2024年第8期41卷 1465-1482页

作者： Jiazhen ZHAO Shengping he ke FAN Huijun WANG Fei LI key Laboratory of Meteorological Disaster Ministry of Education/Joint International Research Laboratory of Climate and Environment Change(ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)Nanjing University of Information Science&TechnologyNanjing 210044China Geophysical Institute University of Bergen and Bjerknes Centre for Climate ResearchBergen 5007Norway School of Atmospheric Science Sun Yat-sen Universityand Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Zhuhai 519082China Nansen Environmental and Remote Sensing Center and Bjerknes Centre for Climate Research Bergen 5007Norway Nansen-Zhu International Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519082China

Precipitous Arctic sea-ice decline and the corresponding increase in Arctic open-water areas in summer months give more space for sea-ice growth in the subsequent cold seasons. Compared to the decline of the entire Arctic multiyear sea ice,changes in newly formed sea ice indicate more thermodynamic and dynamic information on Arctic atmosphere–ocean–ice interaction and northern mid–high latitude atmospheric teleconnections. here, we use a large multimodel ensemble from phase 6 of the Coupled Model Intercomparison Project(CMIP6) to investigate future changes in wintertime newly formed Arctic sea ice. The commonly used model-democracy approach that gives equal weight to each model essentially assumes that all models are independent and equally plausible, which contradicts with the fact that there are large interdependencies in the ensemble and discrepancies in models' performances in reproducing observations. Therefore, instead of using the arithmetic mean of well-performing models or all available models for projections like in previous studies, we employ a newly developed model weighting scheme that weights all models in the ensemble with consideration of their performance and independence to provide more reliable projections. Model democracy leads to evident bias and large intermodel spread in CMIP6 projections of newly formed Arctic sea ice. However, we show that both the bias and the intermodel spread can be effectively reduced by the weighting scheme. Projections from the weighted models indicate that wintertime newly formed Arctic sea ice is likely to increase dramatically until the middle of this century regardless of the emissions ***, it may decrease(or remain stable) if the Arctic warming crosses a threshold(or is extensively constrained).

关键词： wintertime newly formed Arctic sea ice model democracy model weighting scheme model performance model independence

Analytical and Experimental Research on Wave Scattering by an Open-Type Rectangular Breakwater with Horizontal Perforated Plates

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Journal of Ocean University of China 2024年第5期23卷 1185-1201页

作者： he Shuyue LIU yong LI Huajun Fisheries College Ocean University of China Shandong Province key Laboratory of Ocean Engineering Ocean University of China

This study proposes a novel open-type rectangular breakwater combined with horizontal perforated plates on both sides to enhance the sheltering effect of the rectangular box-type breakwaters against longer waves. The hydrodynamic characteristics of this breakwater are analyzed through analytical potential solutions and experimental tests. The quadratic pressure drop conditions are exerted on the horizontal perforated plates to facilitate assessing the effect of wave height on the dissipated wave energy of breakwater through the analytical solution. The hydrodynamic quantities of the breakwater, including the reflection, transmission, and energyloss coefficients, together with vertical and horizontal wave forces, are calculated using the velocity potential decomposition method as well as an iterative algorithm. Furthermore, the reflection and transmission coefficients of the breakwater are measured by conducting experimental tests at various wave periods, wave heights, and both porosities and widths of the horizontal perforated plates. The analytical predicted results demonstrate good agreement with the iterative boundary element method solution and measured data. The influences of variable incident waves and structure parameters on the hydrodynamic characteristics of the breakwater are investigated through further calculations based on analytical solutions. Results indicate that horizontal perforated plates placed on the water surface for both sides of the rectangular breakwater can enhance the wave dissipation ability of the breakwater while effectively decreasing the transmission and reflection coefficients.

关键词： analytical solution experimental test horizontal perforated plates hydrodynamic characteristics rectangular breakwater

Actor-Critic-Based UAV-Assisted Data Collection in the Wireless Sensor Network

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China Communications 2024年第4期21卷 163-177页

作者： Huang Xiaoge Wang Lingzhi he yong Chen Qianbin School of Communications and Information Engineering Chongqing University of Posts and TelecommunicationsChongqing 400065China

Wireless Sensor Network(WSN)is widely utilized in large-scale distributed unmanned detection scenarios due to its low cost and flexible ***,WSN data collection encounters challenges in scenarios lacking communication *** aerial vehicle(UAV)offers a novel solution for WSN data collection,leveraging their high *** this paper,we present an efficient UAV-assisted data collection algorithm aimed at minimizing the overall power consumption of the ***,a two-layer UAV-assisted data collection model is introduced,including the ground and aerial *** ground layer senses the environmental data by the cluster members(CMs),and the CMs transmit the data to the cluster heads(CHs),which forward the collected data to the *** aerial network layer consists of multiple UAVs that collect,store,and forward data from the CHs to the data center for ***,an improved clustering algorithm based on K-Means++is proposed to optimize the number and locations of ***,an Actor-Critic based algorithm is introduced to optimize the UAV deployment and the association with ***,simulation results verify the effectiveness of the proposed algorithms.

关键词： actor critic data collection deep reinforcement learning unmanned aerial vehicle wireless sensor network

Dynamic Update Scheme of Spectrum Information Based on Spectrum Opportunity Incentive in the Database-Assisted Dynamic Spectrum Management

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China Communications 2024年第3期21卷 75-90页

作者： Zhang Yu Chen yong he Panfeng Cai Yueming Sixty-third Research Institute National University of Defense TechnologyNanjing 210007China College of Communications Engineering Army of Engineering UniversityNanjing 210007China

To solve the problem of delayed update of spectrum information(SI) in the database assisted dynamic spectrum management(DB-DSM), this paper studies a novel dynamic update scheme of SI in DB-DSM. Firstly, a dynamic update mechanism of SI based on spectrum opportunity incentive is established, in which spectrum users are encouraged to actively assist the database to update SI in real time. Secondly, the information update contribution(IUC) of spectrum opportunity is defined to describe the cost of accessing spectrum opportunity for heterogeneous spectrum users, and the profit of SI update obtained by the database from spectrum allocation. The process that the database determines the IUC of spectrum opportunity and spectrum user selects spectrum opportunity is mapped to a Hotelling model. Thirdly, the process of determining the IUC of spectrum opportunities is further modelled as a Stackelberg game by establishing multiple virtual spectrum resource providers(VSRPs) in the database. It is proved that there is a Nash Equilibrium in the game of determining the IUC of spectrum opportunities by VSRPs. Finally, an algorithm of determining the IUC based on a genetic algorithm is designed to achieve the optimal IUC. The-oretical analysis and simulation results show that the proposed method can quickly find the optimal solution of the IUC, and ensure that the spectrum resource provider can obtain the optimal profit of SI update.

关键词： database-assisted dynamic spectrum management Hotelling information updating contribution spectrum information updating Stackelberg

Effects of vibration conditions,spatial confinement and friction on mixing and segregation characteristics of mixed pebble beds for CFETR WCCB blanket

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Particuology 2024年第2期85卷 268-279页

作者： yong Liu Chongyang he Cong Wang Lei Chen Songlin Liu Institute of Plasma Physics Hefei Institutes of Physical ScienceChinese Academy of SciencesHefei230031China University of Science and Technology of China Hefei230027China Chengdu University Chengdu610106China Zhejiang Lab Hangzhou310000China

This paper presents the study of the dynamic characteristics of confined mixed pebble beds with different friction under different vibration conditions using the discrete element ***λsegre-gation index is used to quantify the degree of particle mixing or *** percolation,convection and diffusion mechanisms are responsible for the segregation patterns of the mixed *** results show the degree of segregation can be suppressed by decreasing the vibration acceleration or free space height below a *** simulation reveals the threshold of vibration acceleration or free space height both are related to the bed height increment which determines the strength of the percolation *** addition,the strength of percolation and convection becomes weaker by decreasing the friction of particles and walls,which makes the pebbled bed remains in a mixed state under *** findings are significant to clarify the main factors behind the three segregation mechanisms and hence provide solutions to retaining the mixed state of the Li2TiO3&Be12Ti mixed pebble bed.

关键词： Vibration Segregation Binary pebble bed Discrete element method

Shear-thinning Catechol-modified Chitosan Hydrogel Loaded with Silver Nanoparticles for Endoscopic Submucosal Dissection

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Chinese Journal of Polymer Science 2024年第8期42卷 1147-1155页

作者： Wen-Jun Feng Yan-he Wu Xiao-Yang Liu Zheng-ke Wang MOE key Laboratory of Macromolecular Synthesis and Functionalization Department of Polymer Science and EngineeringZhejiang UniversityHangzhou 310058China

Shear-thinning hydrogels have emerged for endoscopic submucosal dissection,while wound intervention after surgery has rarely been ***,a catechol-modified chitosa n hydrogel with shear-thinning property was developed for simultaneously facilitating endoscopic submucosal dissection and postoperative wound *** from the shear-thinning and self-healing characteristics,the asprepared hydrogel showed easily endoscopic *** also performed very well as submucosal cushion,which could remain above 70%after injection for 120 min in ex vivo porcine large intestine *** fact,the cushion height of normal saline dramatically decreased to 46%of the initial height at 30 *** nanoparticles encapsulated into the network endowed the hydrogel with almost reached 100%antibacterial effect against *** and *** hemolysis ratio of the hydrogel was calculated to be as low as 0.8%.Combined with good hemocompatibility and cytocompatibility,the as-prepared hydrogel displayed much higher in vivo wound closu re and healing efficacy than normal *** results demonstrated the superiority of the shear-thinning chitosan hydrogel in facilitating clinical endoscopic submucosal dissection surgery.

关键词： Shear-thinning hydrogel Endoscopic mucosal dissection Wound healing Catechol-modified chitosan Silver nanoparticles

Numerical Simulation on Radon Retardation Behavior of Covering Floats in Radon-Containing Water

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Biomedical and Environmental Sciences 2024年第4期37卷 406-417页

作者： LIU Shu Yuan ZHANG Li YE yong Jun DING Ku ke National Institute for Radiological Protection Chinese Center for Disease Control and PreventionBeijing 100088China Office for Public health Management Chinese Center for Disease Control and PreventionBeijing 102206China key Discipline Laboratory for National Defense for Biotechnology in Uranium Mining and Hydrometallurgy University of South ChinaHengyang 421001HunanChina

Objective This study aimed to efficiently reduce the release of radon from water bodies to protect the *** Based on the sizes of the experimental setup and modular float,computational fluid dynamics(CFD)was used to assess the impact of the area coverage rate,immersion depth,diffusion coefficient,and radon transfer velocity at the gas–liquid interface on radon migration and exhalation of radon-containing *** on the numerical simulation results,an estimation model for the radon retardation rate was *** effectiveness of the CFD simulation was evaluated by comparing the experimental and simulated variation values of the radon retardation rate with the coverage area *** The effect of radon transfer velocity on radon retardation in water bodies was minor and insignificant according to the appropriate value;therefore,an estimation model of the radon retardation rate of the coverage of a radon-containing water body was constructed using the synergistic impacts of three factors:area coverage rate,immersion depth,and diffusion *** deviation between the experimental and simulated results washe numerical simulation conditions,an estimation model of the radon retardation rate of covering floats in water bodies under the synergistic effect of multiple factors was obtained,which provides a reference for designing covering floats for radon retardation in radoncontaining water.

关键词： Radon-containing water Radon retardation rate CFD Coverage experiment Optimized design

Recent progress on impact induced reaction mechanism of reactive alloys

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Defence Technology（防务技术） 2024年第7期37卷 69-95页

作者： Yansong Yang Chuanting Wang Yuanpei Meng Yue Ma Lei Guo Yuan he Zhichao Sun yong he School of Mechanical Engineering Nanjing University of Science and TechnologyNanjing 210094JiangsuChina

In recent years,in order to improve the destructive effectiveness of munitions,the use of new types of destructive elements is an important way to improve destructive *** a new type of reactive material,reactive alloy contains a large portion of reactive metal elements(Al,Mg,Ti,Zr,etc.),which breaks up under high-velocity impact conditions,generating a large number of high-temperature combustible fragments,which undergo a violent combustion reaction with *** with traditional metal polymers(Al-PTFE)and other reactive composites,it has higher density and strength,excellent mechanical properties and broader application ***,researchers have mainly investigated the impact energy release mechanism of reactive alloys through impact tests,and found that there are several important stages in the process of the material from fragmentation to reaction,i.e.,impact fragmentation of the material,rapid heating and combustion *** paper focuses on three problems that need to be solved in the impact-induced energy release process of reactive alloys,namely:the fragmentation mechanism and size distribution law of the fragments produced by the impact of the material on the target,the relationship between the transient temperatures and the size of the fragments,and the reaction temperatures and size thresholds of the fragments to undergo the chemical *** current status of the research of the above problems is reviewed,some potential directions to reveal the impact induced reaction mechanism of reactive alloy is discussed.

关键词： Reactive alloys Impact Fragmentation Mass and size distribution Shock temperature rise Adiabatic shear Combustion