检索结果-南通市图书馆

Earthquake Research Advances 2024年第1期4卷 67-75页

作者： Yuteng Cao Zhe Qu xiaodong ji Key Laboratory of Earthquake Engineering and Engineering Vibration Institute of Engineering MechanicsChina Earthquake AdministrationHarbin150080China Key Laboratory of Earthquake Disaster Mitigation Ministry of Emergency ManagementHarbin150080China Key Laboratory of Civil Engineering Safety and Durability of China Education Ministry Department of Civil EngineeringTsinghua UniversityBeijing100084China

To enable the experimental assessment of the seismic performance of full-scale nonstructural elements with multiple engineering parameters(EDPs),a three-layer testbed named Nonstructural Element Simulator on Shake Table(NEST)has been developed.The testbed consists of three consecutive floors of steel structure.The bottom two floors provide a space to accommodate a full-scale room.To fully explore the flexibility of NEST,we propose a novel control strategy to generate the required shake table input time histories for the testbed to track the target floor motions of the buildings of interest with high accuracy.The control strategy contains two parts:an inverse dynamic compensation via simulation of feedback control systems(IDCS)algorithm and an offline iteration procedure based on a refined nonlinear numerical model of the testbed.The key aspects of the control strategy were introduced in this paper.Experimental tests were conducted to simulate the seismic responses of a full-scale office room on the 21^(st)floor of a 42-story high-rise building.The test results show that the proposed control strategy can reproduce the target floor motions of the building of interest with less than 20%errors within the specified frequency range.

关键词： Shake table test Nonstructural element High-rise building Open-loop IDCS algorithm Off-line iteration

Energy-Efficient Full-Duplex UAV Relaying with Trajectory Optimization and Power Control in Maritime Communication Environments

在线全文

学校读者我要写书评

暂无评论

China Communications 2022年第12期19卷 216-231页

作者： Lili Guo xiaodong ji Shibing Zhang School of Information Science and Technology Nantong UniversityNantong 226019China Nantong University Xinglin College Nantong 226236China

This paper solves an energy-efficient optimization problem of a fixed-wing unmanned aerial vehicle(UAV) assisted full-duplex mobile relaying in maritime communication environments.Taking the speed and the acceleration of the UAV and the information-causality constraints into consideration,the energy-efficiency of the system under investigation is maximized by jointly optimizing the UAV’s trajectory and the individual transmit power levels of the source and the UAV relay nodes.The optimization problem is non-convex and thus cannot be solved directly.Therefore,it is decoupled into two subproblems.One sub-problem is for the transmit power control at the source and the UAV relay nodes,and the other aims at optimizing the UAV s flight trajectory.By using the Lagrangian dual and Dinkelbach methods,the two sub-problems are solved,leading to an iterative algorithm for the joint design of transmit power control and trajectory optimization.Computer simulations demonstrated that by conducting the proposed algorithm,the flight trajectory of the UAV and the individual transmit power levels of the nodes can be flexibly adjusted according to the system conditions,and the proposed algorithm can achieve signiflcantly higher energy efficiency as compared with the other benchmark schemes.

关键词： UAV communication full-duplex relaying(FDR) energy-efficiency maritime communication

CAS-ESM2.0 Successfully Reproduces Historical Atmospheric CO_(2) in a Coupled Carbon−Climate Simulation

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2024年第4期41卷 572-580页

作者： jiawen ZHU Juanxiong HE Duoying ji Yangchun LI He ZHANG Minghua ZHANG xiaodong ZENG Kece FEI jiangbo jiN International Center for Climate and Environment Sciences Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD) Nanjing University of Information Science&TechnologyNanjing 210044China College of Global Change and Earth System Science Beijing Normal UniversityBeijing 100875China State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China School of Marine and Atmospheric Sciences Stony Brook UniversityNY 11790USA University of Chinese Academy of Sciences Beijing 100049China

The atmospheric carbon dioxide(CO_(2))concentration has been increasing rapidly since the Industrial Revolution,which has led to unequivocal global warming and crucial environmental change.It is extremely important to investigate the interactions among atmospheric CO_(2),the physical climate system,and the carbon cycle of the underlying surface for a better understanding of the Earth system.Earth system models are widely used to investigate these interactions via coupled carbon-climate simulations.The Chinese Academy of Sciences Earth System Model version 2(CAS-ESM2.0)has successfully fixed a two-way coupling of atmospheric CO_(2)with the climate and carbon cycle on land and in the ocean.Using CAS-ESM2.0,we conducted a coupled carbon-climate simulation by following the CMIP6 proposal of a historical emissions-driven experiment.This paper examines the modeled CO_(2)by comparison with observed CO_(2)at the sites of Mauna Loa and Barrow,and the Greenhouse Gases Observing Satellite(GOSAT)CO_(2)product.The results showed that CAS-ESM2.0 agrees very well with observations in reproducing the increasing trend of annual CO_(2)during the period 1850-2014,and in capturing the seasonal cycle of CO_(2)at the two baseline sites,as well as over northern high latitudes.These agreements illustrate a good ability of CAS-ESM2.0 in simulating carbon-climate interactions,even though uncertainties remain in the processes involved.This paper reports an important stage of the development of CAS-ESM with the coupling of carbon and climate,which will provide significant scientific support for climate research and China’s goal of carbon neutrality.

关键词： CAS-ESM atmospheric CO_(2) coupled carbon-climate simulation emissions-driven CMIP6 experiment

Factor analysis and countermeasure simulation on the socio-ecological environment risks during the development of coalbed methane:based on the DEMATEL and FCM models

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Population,Resources and Environment 2022年第1期20卷 69-79页

作者： Ye Xue xiaodong ji Chongyi Xue College of Economics and Management Taiyuan University of TechnologyTaiyuan030024China

The socio-ecological environmental problem caused by the development of coalbed methane(CBM)is becoming more serious,so it is very significant for accelerating the development of CBM industrialization to identify the main influential factors of socioecological environmental risks and take effective risk prevention measures.Based on the triangular fuzzy number method,this paper firstly establishes a comprehensive correlation matrix.Then,the affected factors of socio-ecological environmental risks are analyzed by the DEMATEL method during the development of CBM.Then according to the aspects of centrality and causality,the key indicators are determined.Furthermore,the scenario simulation based on the FCM,the steady-state value and the comprehensive importance of key indicators,and the core indicators are selected.Finally,the scenario simulation of risk management countermeasure is done.The results show that:①The index weights are calculated by the triangular fuzzy numbers,and the correlation matrix in DEMATEL is obtained by the weight ratio,which reduces the shortcomings and the subjectivity of traditional DEMATEL method.②The correlation matrix in FCM is established based on the comprehensive correlation matrix in the above improved DEMATEL,which not only makes the FCM model more comprehensive and reduces the difficulty that the FCM correlation matrix is obtained considering the indirect influence relationship between indicators,but also makes up for the disadvantages that DEMATEL excludes during the selection of the core indexes,which are the considerations of the dynamic change of the importance of the indicators.③The rate of forestry and grass coverage,the ratio of investment in prevention and construction,the pollution index of soil Merlot,the reliability of machinery and equipment,the standard evaluation index of major pollution factors of underground water,and the ability of personal risk prevention are the key indicators,in which the rate of forestry and grass coverage,the ratio of investment in prevention an

关键词： Coalbed methane development Social ecological environment risk Core indicator Scenario simulation

Effect of cerium alloying on microstructure,texture and mechanical properties of magnesium during cold-rolling process

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第5期42卷 1001-1008,I0007页

作者： Zhen Zhang Huanhuan Chen Shiju Cao jinhua Peng Peng Guo Chang Long Shan Wang Chang Chen Yong Wu ji'an Huang xiaodong Du Haigen Wei School of Materials Science and Engineering Hefei University of TechnologyHefei230009China NationalLocal Joint Research Center of Non-ferrous Metal Materials and Processing Technology Hefei230009China Laboratory of Nonferrous Metal Material and Processing Engineering of Anhui Province Hefei230009China School of Materials Science and Engineering Jiangsu University of Science and TechnologyZhenjiang212003China Institute of Industry and Equipment Technology Hefei University of TechnologyHefei230009China Faculty of Materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou341000China

Hot-extrusion and cold-rolling were conducted on Mg-Ce binary alloys to explore the effect of cerium(Ce)on microstructure,texture and mechanical properties of Mg alloys.The addition of Ce results in significant grain refinement both in as-cast and hot-extruded samples.The basal texture is also weakened after extrusion and an inclined basal texture is formed with Ce addition.The strength and elongation of the Mg-Ce alloys are improved simultaneously due to such grain refinement and texture weakening effect.After cold-rolling,plenty of twins are found in the pure Mg and AZ31 plates while grains in the Mg-0.3Ce plate deform more uniformly without lamellar twin structure.Furthermore,Mg-0.3Ce alloys own strong and continuous strain hardening because Ce atoms and Mg-Ce precipitated phases serve as obstacles for dislocation slip.

关键词： Mg-Ce alloys Hot extrusion Cold-rolling Rare earths

在线全文

学校读者我要写书评

暂无评论

低快拍下混合信号DOA快速估计算法

系统工程与电子技术 2024年第2期46卷 722-728页

作者：姚震杨闯纪晓东北京邮电大学网络与交换技术国家重点实验室北京100876

实时定位移动设备在电子对抗系统中至关重要,其性能主要取决于波达角(direction of arrival,DOA)的估计速度。低快拍是快速DOA估计的先决条件。目前基于稀疏重构算法的DOA估计具有适应低快拍的优势,但估计精度受限于初始观测矩阵,且估... 详细信息

实时定位移动设备在电子对抗系统中至关重要,其性能主要取决于波达角(direction of arrival,DOA)的估计速度。低快拍是快速DOA估计的先决条件。目前基于稀疏重构算法的DOA估计具有适应低快拍的优势,但估计精度受限于初始观测矩阵,且估计速度受限于观测矩阵高维度的多次迭代。为此,提出一种空间差分矩阵和稀疏重构耦合的低快拍下高精度快速估计算法。首先利用空间差分矩阵消除非相干信号和噪声对相干信号估计结果的影响,提升初始观测矩阵的准确度;然后对完备字典做前后空间平滑处理,克服高维度信号处理复杂难题,实现快速估计;最后分别估计非相干信号和相干信号。仿真验证结果表明,相比稀疏重构方法,所提方案初值敏感度显著降低,在保障精度相当甚至小幅度提升的前提下,运行时间复杂度降低50%以上。

关键词：波达角估计稀疏重构空间差分混合信号空间平滑

在线全文

学校读者我要写书评

暂无评论

混合概率信道下的全双工无人机中继轨迹优化

系统仿真学报 2024年第6期36卷 1369-1377页

作者：王涛吉晓东南通大学信息科学技术学院江苏南通226019

研究了固定翼无人机作为全双工移动中继,通过混合概率信道为源节点向目标节点转发数据的飞行轨迹优化设计,在满足源与目标通信任务量要求的情况下,最小化无人机飞行能耗。建立了跑道形和混合轨迹的两种最优化问题,该问题是非凸问题,难... 详细信息

研究了固定翼无人机作为全双工移动中继,通过混合概率信道为源节点向目标节点转发数据的飞行轨迹优化设计,在满足源与目标通信任务量要求的情况下,最小化无人机飞行能耗。建立了跑道形和混合轨迹的两种最优化问题,该问题是非凸问题,难以求得闭式解,先将混合信道增益用平均信道增益代替,并利用泰勒展开求出中继和目标节点接收数据量的下界,以此化简约束,从而得到原问题的近似问题。利用遗传算法和内点法求解近似问题,给出跑道形和混合轨迹两种无人机轨迹设计。实验结果表明:跑道形轨迹在任何场景下均有较好的节能效果;在大任务量和源与目标距离较远时,混合轨迹节能效果好于直线和圆形轨迹。时间复杂度分析发现,遗传算法的复杂度小于内点法,更加适用于实时性要求高的场景。

关键词：无人机通信混合概率信道轨迹设计全双工能耗最小化

Scalable fabrication of graphene-assembled multifunctional electrode with efficient electrochemical detection of dopamine and glucose

在线全文

学校读者我要写书评

暂无评论

Nano Research 2023年第5期16卷 6361-6368页

作者： xiaodong ji Xin Zhao Zixin Zhang Yunfa Si Wei Qian Huaqiang Fu Zibo Chen Zhe Wang Huihui jin Zhugen Yang Daping He State Key Laboratory of Silicate Materials for Architectures Wuhan University of TechnologyWuhan 430070China Hubei Engineering Research Center of RF-Microwave Technology and Application Wuhan University of TechnologyWuhan 430070China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China School of Information Engineering Wuhan University of TechnologyWuhan 430070China School of Water Energy and EnvironmentCranfield UniversityMilton KeynesMK430ALUK

Conventional glassy carbon electrodes(GCE)cannot meet the requirements of future electrodes for wider use due to low conductivity,high cost,non-portability,lack of flexibility.Therefore,cost-effective and wearable electrode enabling rapid and versatile molecule detection is becoming important,especially with the ever-increasing demand for health monitoring and point-ofcare diagnosis.Graphene is considered as an ideal electrode due to its excellent physicochemical properties.Here,we prepare graphene film with ultra-high conductivity and customize the 3-electrode system via a facile and highly controllable laser engraving approach.Benefiting from the ultra-high conductivity(5.65×10^(5)S·m^(−1)),the 3-electrode system can be used as multifunctional electrode for direct detection of dopamine(DA)and enzyme-based detection of glucose without further metal deposition.The dynamic ranges from 1–200μM to 0.5–8.0 mM were observed for DA and glucose,respectively,with a limit of detection(LOD)of 0.6μM and 0.41 mM.Overall,the excellent target detection capability caused by the ultra-high conductivity and ease modification of graphene films,together with their superb mechanical properties and ease of mass-produced,provides clear potential not only for replacing GCE for various electrochemical studies but also for the development of portable and highperformance electrochemical wearable medical devices.

关键词： graphene film ultra-high conductivity multifunctional electrode point-of-care diagnosis wearable medical devices

Anchorage properties at the interface between soil and roots with branches

维普期刊数据库评论

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 Forestry Research 2017年第1期28卷 83-93页

作者： xiaodong ji Lihua Chen Ao Zhang Key Laboratory of Soil and Water Conservation and Desertification Combating Ministry of Education of ChinaBeijing Forestry University100083 BeijingChina

Roots play an important role in stabilizing and strengthening soil. This article aims to study the mechanical properties of the interface between soil and roots with branches, using the pullout test method in the laboratory. The mechanical properties of the soil-root with branches interface is determined through the pullout-force and root-slippage curve （F-S curve）. The results of investigating 24 Pinus tabulaeformis single roots and 55 P. tabulaeformis roots with branches demonstrated three kinds of pullout test failures： breakage failure on branching root, breakage failure on branching node, and pullout failure. The branch angle had a remarkable effect on the failure mode of the roots with branches： the maximum pullout force increased with the sum of the branch diameters and the branch angle. The peak slippage and the initial force had a positive correlation with the sum of the branch diameter. The sig- nificance test of correlation between branch angle and the initial force, however, showed they had no correlation. Branch angle and branch root diameter affect the anchorage properties between root system and soil. Therefore, it is important to investigate the anchorage mechanics of the roots with branches to understand the mechanism of root reinforcement and anchorage.

关键词： Root-soil interface mechanics Pullout test method Root branches Branch angle

Enhancing the interfacial binding strength between modular stretchable electronic components

在线全文

学校读者我要写书评

暂无评论

National Science Review 2023年第1期10卷 49-67页

作者： Shaobo ji xiaodong Chen Innovative Centre for Flexible Devices(iFLEX) Max Planck-NTU Joint Lab for Artificial SensesSchool of Materials Science and Engineering Nanyang Technological University Institute of Materials Research and Engineering(IMRE) Agency for Science Technology and Research

Stretchable electronics are emerging for personalized and decentralized clinics,wearable devices and human-machine interactions.Nowadays,separated stretchable functional parts have been well developed and are approaching practical usage.However,the production of whole stretchable devices with full functions still faces a huge challenge:the integration of different components,which was hindered by the mechanical mismatch and stress/strain concentration at the connection interfaces.To avoid connection failure in stretchable devices,a new research focus is to improve the interfacial binding strength between different components.In this review,recent developments to enhance interfacial strength in wearable/implantable electronics are introduced and catalogued into three major strategies:(ⅰ) covalent bonding between different device parts,(ⅱ) molecular interpenetration or mechanical interlocking at the interfaces and(ⅲ) covalent connection between the human body and devices.Besides reviewing current methods,we also discuss the existing challenges and possible improvements for stretchable devices from the aspect of interfacial connections.

关键词： stretchable electronics interfacial strength covalent bonding mechanical interlocking device–human interfaces