检索结果-南通市图书馆

Acollaborative target tracking algorithm formultiple UAVs with inferior tracking capabilities

在线全文

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2021年第10期22卷 1334-1350页

作者： Zhi Zheng Shuncheng CAI College of Computer and Cyber Security Fujian Normal UniversityFuzhou 350117China

Target tracking is one of the hottest topics in the field of drone research.In this paper,we study the multiple unmanned aerial vehicles(multi-UAV)collaborative target tracking problem.We propose a novel tracking method based on intention estimation and effective cooperation for UAVs with inferior tracking capabilities to track the targets that may have agile,uncertain,and intelligent motion.For three classic target motion modes,we first design a novel trajectory feature extraction method with the least dimension and maximum coverage constraints,and propose an intention estimation mechanism based on the environment and target trajectory features.We propose a novel Voronoi diagram,called MDA-Voronoi,which divides the area with obstacles according to the minimum reachable distance and the minimum steering angle of each UAV.In each MDA-Voronoi region,the maximum reachable region of each UAV is defined,the upper and lower bounds of the trajectory coverage probability are analyzed,and the tracking strategies of the UAVs are designed to effectively reduce the tracking gaps to improve the target sensing time.Then,we use the Nash Q-learning method to design the UAVs’collaborative tracking strategy,considering factors such as collision avoidance,maneuvering constraints,tracking cost,sensing performance,and path overlap.By designing the reward mechanism,the optimal action strategies are obtained as the control input of the UAVs.Finally,simulation analyses are provided to validate our method,and the results demonstrate that the algorithm can improve the collaborative target tracking performance for multiple UAVs with inferior tracking capabilities.

关键词： Collaborative target tracking Intent estimation MDA-Voronoi diagram Multi-UAV Inferior

Simulation and prediction of membrane fusion dynamics

在线全文

学校读者我要写书评

暂无评论

Theoretical & Applied Mechanics Letters 2022年第1期12卷 49-55页

作者： Zhi Zheng Shouqin Lü Mian Long Center of Biomechanics and Bioengineering Key Laboratory of Microgravity(National Microgravity Laboratory)Beijing Key Laboratory of Engineered Construction and Mechanobiologyand CAS Center for Excellence in Complex System MechanicsInstitute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China

Membrane fusion is an important process by which biological membranes perform their life activities. Simulations show that the membrane fusion process happens mainly through three pathways, where the Stalk-Pore hypothesis, in which two membranes come into close contact to form a stalk to a hemifusion intermediate, and then the fusion pore opens to achieve completely fusion, is widely accepted, and there exist two free energy barriers that break the current structural steady state for lipid rearrangement. Factors of lipid composition, mechanical environment, protein and ion have regulatory roles in the membrane fusion process by effecting membrane curvature structurally and the free energy barriers from energetic perspective. Meanwhile, many theoretical models, represented by the Helfrich model, have been proposed to predict the membrane fusion process. In this paper, we review the research process of membrane fusion and mainly introduce the dynamics of membrane fusion, regulation factors and typical theoretical models.

关键词： Membrane fusion Hemifusion intermediates Fusion pathway Regulation Helfrich model

在线全文

学校读者我要写书评

暂无评论

国医大师路志正治疗肺结节病学术经验

中华中医药杂志 2023年第6期38卷 2629-2632页

作者：刘学春王光涛路志正中国中医科学院中国医史文献研究所北京100700 中国人民解放军战略支援部队特色医学中心北京100101 中国中医科学院广安门医院北京100053

国医大师路志正教授年逾期颐,善学而寿长,融古铸今,创立新说。在临证方面,注重治疗前后参考现代医学检查和检验数据,以证中医之疗效。对于中医古籍没有记载的病,强调变则通,通则达,不囿于现代西医之病名,不被西医诊断所束缚,坚持中医诊... 详细信息

国医大师路志正教授年逾期颐,善学而寿长,融古铸今,创立新说。在临证方面,注重治疗前后参考现代医学检查和检验数据,以证中医之疗效。对于中医古籍没有记载的病,强调变则通,通则达,不囿于现代西医之病名,不被西医诊断所束缚,坚持中医诊疗特色,谨遵中医理论辨证论治。路教授根据已颁布的有关肺结节病的专家共识,结合中医相关理论探讨了其病因病机、辨证论治原则,认为肺结节的病位在肺,多与肝、脾、胃功能失调有关,病变可累及于肾,强调机体正气不足是肺结节病形成的重要因素,提出了以“调畅气机以使痰有出路,轻灵宣肺令痰无居所,活泼醒脾先安未受邪之地”作为基本的治疗原则,在临床中取得了良好的疗效。

关键词：国医大师名医经验路志正肺结节癥瘕医案验案

Overcome Debye Length Limitations for Biomolecule Sensing Based on Field Effective Transistors

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2021年第4期39卷 999-1008页

作者： Zhi Zheng Hongyuan Zhang Tianyou Zhai Fan Xia Engineering Research Center of Nano-Geomaterials of Ministry of Education Faculty of Materials Science and ChemistryChina University of GeosciencesWuhanHubei430074 China State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhanHubei 430074Chino

Biosensors based on field effective transistor(FET)have aroused tremendous attention in the past few years owning to their huge application in drug discovery,disease diagnosis and environmental monitoring.The FET biosensors possess small volume,high sensitivity at ultra-low concentration,considerable mechanical strength,as well as excellent stability in solution,which plays a vital role in the point of care testing(POCT)systems.Recent advances have summarized some progress involved in the improvement of morphology and structure of channel materials,the functionalization of organic molecule,the influence of device operation and sensing environment on the detecting performance.However,for FET biosensors,the charge screening phenomena were inevitable in the solution,which seriously degrade the device performance.In this article,we summarize recent advances to overcome debye length limitations for biomolecule sensing based on FET.We will firstly describe the charge screening mechanism,then focous on the strategy to overcome charge screening,including synthesizing special channel materials with crumpled morphology,designing aptamer binding mode,and modulating device measurement.Finally,we discuss the major challenges and perspectives about overcoming debye length limitations of FET biosensors.These summaries provide further insights to realize real-time,lable-free,high-sensitivity FET sensors for medical healthcare.

关键词： Debye length Interactions Field effective transistors Biosensors Biomolecule

Optimization of an annular wave energy converter in a wind-wave hybrid system

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2023年第2期35卷 338-350页

作者： Bin-zhen Zhou Zhi Zheng Yu Wang Peng Jin Lin Cui Liang Cheng School of Civil Engineering and Transportation South China University of TechnologyGuangzhou510641China School of Marine Science and Engineering South China University of TechnologyGuangzhou510641China National Ocean Technology Center Tianjin300112China

A hybrid system of a spar-type floating offshore wind turbine and a heaving annular wave energy converter(WEC)provides a promising solution for collocated ocean renewable energy exploitation.The performance of the hybrid system depends on the dimensions of the WEC.Here an optimization method is proposed to determine the outer radius and the draft of the WEC under the wave condition in a randomly chosen operational site.First,three candidate models are selected based on three operational conditions of energy harvest:(1)The natural frequency of the system is matched with the peak wave frequency in the target site(referred to as synchronized mode),where the wind turbine and the WEC nearly heave together in a near-resonance condition,(2)The natural frequency of the WEC is matched with the peak wave frequency(ring mode),(3)The maximum wave power is harnessed under the peak wave frequency(target mode).Then the candidate modes are evaluated to obtain an optimum.Results show that the extracted wave power under the above operational conditions has an upper bound that can hardly be surpassed by enlarging the dimensions of the WEC only.The optimal annual wave energy production is achieved in the synchronized mode because of the superior performance of WEC over a wide bandwidth of effective energy conversion.

关键词： Spar-type wind turbine wave energy converter(WEC) hybrid system model selection optimization

Effects of Ni content and tempering temperatures on microstructure and properties of medium-carbon cast steel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2023年第8期30卷 1524-1536页

作者： Xiao-bo Cui Tian-long Liu zhi-bin zheng zhi-qiang Guo Kai-hong zheng Pei-xian Han School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870LiaoningChina Institute of New Materials Guangdong Academy of SciencesNational Engineering Research Center of Powder Metallurgy of Titanium and Rare MetalsGuangdong Provincial Key Laboratory of Metal Toughening Technology and ApplicationGuangzhou 510651GuangdongChina Guangdong Provincial Iron Matrix Composite Engineering Research Center Guangzhou 510651GuangdongChina Jiangxi Lianfeng Investment Casting Co. Ltd.Yichun 336300JiangxiChina

The microstructure evolution and properties of medium-carbon cast steel alloyed with different Ni contents after tempering at various temperatures have been investigated.The addition of 0.47-1.59 wt.%Ni content results in the formation of 16%-36% retained austenite(RA).The blocky and irregular-polygonal RA mainly forms along the prior austenite grain boundaries,and the tempering temperature does not affect the RA content.The hardness of medium-carbon cast steel is affected by the precipitation of carbides and the hardness of martensite.Excessive RA content is the main cause of intergranular impact rupture and low impact energy.The long-strip carbides formed after tempering at 320℃ would further reduce the impact energy of medium-carbon cast steel.When tempering at 220 and 380℃,the increase in impact energy is attributed to the formation of rod-like and spherical carbides and the low-carbon martensite.For the medium-carbon cast steel with high impact energy,its impact-abrasive wear resistance is more excellent.Micro-cutting and delamination are the primary wear mechanisms.

关键词： Medium-carbon cast steel Ni content Tempering temperature Hardness Impact energy Impact-abrasive wear resistance

Investigation on overvoltage caused by vacuum circuit breaker switching off shunt reactor in offshore wind farms

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

High Voltage 2022年第5期7卷 936-949页

作者： Zhi Zheng Qiuqin Sun Jianlan Yang She Chen Feng Wang Lipeng Zhong College of Electrical&Information Engineering Hunan UniversityChangshaChina

The multiple reignitions of vacuum circuit braker(VCB)while switching off the shunt reactor in an offshore wind farm(OWF)would produce a high overvoltage.The post-arc process of ion movement in the vacuum interrupter is analysed.Considering the sheath growth and ion concentration variation,the expression for dielectric recovery strength inside the VCB interrupter is derived.A novel VCB model is implemented in the environment of electromagnetic transient programme based on the new reignition criterion.Then,the switching overvoltage is computed and analysed in detail.For the OWF with high rising rate of transient recovery voltage,the sheath growth must be considered in the VCB model;otherwise,the overvoltage may be underestimated.Using resistor–capacitor(RC)snubber,a new installation scheme is proposed to suppress the overvoltage in the OWF.The results indicate that the proposed scheme can not only reduce the peak and steepness of overvoltage but also damp the high-frequency oscillation.It would not affect the steady-state operation of OWF.Besides,the capacitor of RC snubber normally does not bear the electric stress,and its life expectancy would be greatly enhanced.

关键词： transient vacuum otherwise

Research Progress and Future Perspectives on Rechargeable Na-O_(2) and Na-CO_(2) Batteries

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Energy & Environmental Materials 2021年第2期4卷 158-177页

作者： Zhi Zheng Chang Wu Qinfen Gu Konstantin Konstantinov Jiazhao Wang Institute for Superconducting and Electronic Materials University of WollongongWollongong NSW 2522Australia The Australian Synchrotron(ANSTO) 800 Blackburn RoadClayton VIC 3168Australia

Rechargeable sodium–oxygen(Na-O_(2))and sodium–carbon dioxide(Na-CO_(2))batteries have attracted intensive research attention in recent years owing to their advantages of high theoretical energy density,modest cost,abundance of sodium resources,and promising potential for achieving real sodium–air batteries in large-scale energy storage systems.Nevertheless,current research on Na-O_(2)and Na-CO_(2)batteries is facing enormous challenges,such as low energy efficiency and limited cycle life,which are restricting their progress at the initial stage.Therefore,understanding their working principles,and the chemical and electrochemical reactions of the electrodes is indispensable to achieve their practical application and even the goal of true sodium–air batteries.This review aims to provide an overview of the research developments and future perspectives on Na-O_(2)and Na-CO_(2)batteries,which include the major aspects,such as working mechanisms,air cathode materials design strategies,sodium anode protection,and electrolyte stability.Moreover,the remaining issues and future research directions are also thoroughly discussed and presented.

关键词： anode protection cathode materials electrolytes Na-CO_(2)batteries Na-O_(2)batteries

On Ramanujan Sums over a Dedekind Domain with Finite Norm Property

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2023年第1期39卷 149-160页

作者： zhi Yong zheng Man CHEN Zi Wei HONG School of Mathematics Renmin University of ChinaBeijing 100872P.R.China School of Mathematical Sciences Beihang UniversityBeijing 100191P.R.China

In this paper,we consider Ramanujan’s sums over arbitrary Dedekind domain with finite norm property.We define the Ramanujan’s sumsη(a,A)andη(B,A),where a is an arbitrary element in a Dedekind domain,B is an ideal and A is a non-zero ideal.In particular,we discuss the Kluyver formula and Hèolder formula forη(a,A)andη(B,A).We also prove the reciprocity formula enjoyed byη(B,A)and the orthogonality relations forη(a,A)in the last two parts.

关键词： Dedekind domains Ramanujan Sums primitive additive character reciprocity formula orthogonality property