检索结果-南通市图书馆

Modelling and validation of flash flood inundation in drylands

Journal of geographical sciences 2024年第1期34卷 185-200页

作者： GAO Dan YIN Jie WANG Dandan YANG Yuhan LU Yi CHEN Ruishan School of geographic sciences East China Normal UniversityShanghai 200241China key laboratory of geographic information science of Ministry of Education East China Normal UniversityShanghai 200241China National Disaster Reduction Center of China Ministry of Emergency Management of People's Republic of ChinaBeijing 100124China School of Design Shanghai Jiao Tong UniversityShanghai 200240China

In the context of climate change and human activities,flood disasters in arid mountainous areas have become increasingly frequent,and seriously threatened the safety of people's lives and *** and accurate flash flood inundation modelling is an essential foundational research area,which can aid in the reduction of casualties and the minimization of disaster losses;however,this modelling is also very difficult,and models need to be urgently developed to address flash flood forecasting and *** objective of this study is to construct a numerical modelling method for flash floods in *** on a 2D high-resolution flood numerical model(Flood Map-Hydro Inundation2D),we hindcasted the dynamic process of flash flooding and show the spatio-temporal characteristics of flash flood inundation for the“8·18”flash flood disaster that occurred in Datong county,Qinghai *** results showed that the model output effectively agreed with the observed inundation after the event in terms of both spatial extent and temporal *** flooding mainly occurred between 00:00 and 01:00 on August 18,***,Hejiazhuang and Longwo villages were affected most *** further conducted model sensitivity analysis and found that the model was highly sensitive to both roughness and hydraulic conductivity in drylands,and the effect of hydraulic conductivity was more *** study confirmed the good performance of our model for the simulation of flash flooding in arid areas and provides a potential method for flash flood assessment and management in arid areas.

关键词： flash flood numerical modelling arid areas Datong county Flood Map-Hydro Inundation2D

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

All-optical nanoscale thermometry with silicon carbide color centers

引用

Photonics Research 2024年第8期12卷 1696-1702页

作者： CHENGYING LIU HAIBO HU ZHENGTONG LIU SHUMIN XIAO JUNFENG WANG YU ZHOU QINGHAI SONG Ministry of Industry and information Technology key laboratory of Micro-Nano Optoelectronic information System Guangdong Provincial Key Laboratory of Semiconductor Optoelectronic Materials and Intelligent Photonic SystemsHarbin Institute of TechnologyShenzhen 518055China Pengcheng laboratory Shenzhen 518055China Quantum science Center of Guangdong-Hong Kong-Macao Greater Bay Area Shenzhen-Hong Kong International Science and Technology ParkShenzhen 518045China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China College of Physics Sichuan UniversityChengdu 610065China

All-optical thermometry plays a crucial role in precision temperature measurement across diverse *** defects in solids are one of the most promising sensors due to their excellent sensitivity,stability,and ***,it faces limitations,such as the microwave heating effect and the complexity of spectral *** these challenges,we introduce a novel approach to nanoscale optical thermometry using quantum defects in silicon carbide(SiC),a material compatible with complementary metal-oxide-semiconductor(CMOS)*** method leverages the intensity ratio between anti-Stokes and Stokes emissions from SiC color centers,overcoming the drawbacks of traditional techniques such as optically detected magnetic resonance(ODMR)and zero-phonon line(ZPL)*** technique provides a real-time,highly sensitive(1.06%K^(-1)),and diffraction-limited temperature sensing protocol,which potentially helps enhance thermal management in the future miniaturization of electronic components.

关键词： carbide optical centers

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Layer Hall effect induced by hidden Berry curvature in antiferromagnetic insulators

引用

National science Review 2024年第2期11卷 15-23页

作者： Rui Chen Hai-Peng Sun Mingqiang Gu Chun-Bo Hua Qihang Liu Hai-Zhou Lu X.C.Xie Shenzhen Institute for Quantum science and Engineering and Department of Physics Southern University of Science and Technology(SUSTech) International Quantum Academy Institute for Theoretical Physics and Astrophysics University of Würzburg School of Electronic and information Engineering Hubei University of Science and Technology Guangdong provincial key laboratory of Computational science and Material Design Southern University of Science and Technology Shenzhen key laboratory of Quantum science and Engineering International Center for Quantum Materials School of PhysicsPeking University Collaborative Innovation Center of Quantum Matter CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences

The layer Hall effect describes electrons spontaneously deflected to opposite sides at different layers, which has been experimentally reported in the MnBi2Te4thin films under perpendicular electric fields. Here, we reveal a universal origin of the layer Hall effect in terms of the so-called hidden Berry curvature, as well as material design principles. Hence, it gives rise to zero Berry curvature in momentum space but non-zero layer-locked hidden Berry curvature in real space. We show that, compared to that of a trivial insulator, the layer Hall effect is significantly enhanced in antiferromagnetic topological insulators. Our universal picture provides a paradigm for revealing the hidden physics as a result of the interplay between the global and local symmetries, and can be generalized in various scenarios.

关键词： layerHall effect hidden Berry curvature antiferromagnetic insulator axion insulator, quantum transport

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Sum-Rate Maximization in Active RIS-Assisted Multi-Antenna WPCN

引用

China Communications 2024年第6期21卷 23-39页

作者： Jiang Jie Lyu Bin Chen Pengcheng Yang Zhen School of Communications and information Engineering Nanjing University of Posts and TelecommunicationsNanjing 210003China Jiangsu provincial key laboratory of Photonic and Electronic Materials sciences and Technology Nanjing UniversityNanjing 210003China

In this paper,we propose an active reconfigurable intelligent surface(RIS)enabled hybrid relaying scheme for a multi-antenna wireless powered communication network(WPCN),where the active RIS is employed to assist both wireless energy transfer(WET)from the power station(PS)to energyconstrained users and wireless information transmission(WIT)from users to the receiving station(RS).For further performance enhancement,we propose to employ both transmit beamforming at the PS and receive beamforming at the *** formulate a sumrate maximization problem by jointly optimizing the RIS phase shifts and amplitude reflection coefficients for both the WET and the WIT,transmit and receive beamforming vectors,and network resource *** solve this non-convex problem,we propose an efficient alternating optimization algorithm with the linear minimum mean squared error criterion,semidefinite relaxation(SDR)and successive convex approximation ***,the tightness of applying the SDR is *** results demonstrate that our proposed scheme with 10 reflecting elements(REs)and 4 antennas can achieve 17.78%and 415.48%performance gains compared to the single-antenna scheme with 10 REs and passive RIS scheme with 100 REs,respectively.

关键词： active reconfigurable intelligent surface beamforming sum-rate maximization wireless powered communication network

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Slope-climbing of cropland and its effects in China

引用

Journal of Mountain science 2024年第8期21卷 2754-2769页

作者： CHEN Wanxu XIE Youping YUAN Jintao ZENG Jie YANG Liyan GU Tianci LEI Fan Hubei key laboratory of Regional Ecology and Environmental Change School of Geography and Information EngineeringChina University of GeosciencesWuhan 430074China key laboratory of Natural Resources Monitoring and Supervision in Southern Hilly Region Ministry of Natural ResourcesChangsha 410118China Yunnan key laboratory of Plateau geographic Processes and Environmental Changes Faculty of GeographyYunnan Normal UniversityKunming 650500China

In recent decades,the spatio-temporal patterns of China’s croplands have been reshaped by disturbances from anthropogenic activities,with complex changes in the topographic characteristics of ***-climbing of croplands(SCCL)is an important issue that threatens sustainable agricultural *** providing land with prominent location advantages,SCCL weakens the water and fertilizer retention capacity for cropland,intensifies various geological disasters,and adversely affects the ecological environment and food yield of these *** is crucial to determine the spatio-temporal variation features and effects of SCCL in China to formulate more accurate cropland protection policies and to maintain food security;however,the current lack of relevant studies is detrimental for capturing trends in cropland resources and sustainable cropland *** this study,we constructed a multi-scale slope spectrum for cropland and total terrain to explore the spatial differences and trends of SCCL from a three-dimensional *** evaluated the natural and socioeconomic effects of SCCL in China from multiple *** indicate that the proportion of cropland with slopes below 2°,5°,and 6°in China decreased by 0.43%,0.47%,and 0.50%from 1980 to 2020,*** became apparent during 1980-1990 and 2010-2020,especially over the recent *** cropland climbing index(CCI)and upper limited slope change(ULSC)to measure the spatio-temporal pattern of SCCL were 0.99%and 1.17°,respectively,during *** the agricultural regional scale,the SCCL was also concentrated in 1980-1990 and 2010-2020,and it is more pronounced in the southern *** proportion of provinces and prefecture-level cities with high-intensity SCCL during 1980-2020 were 87.10%and 49.73%,*** was comparatively more pronounced and broader from 2010 to *** this period,17.84%of prefecture-level cities had no SCCL,and the average CCI for all prefecture-level citi

关键词： Croplands Slope spectrum Slope-climbing Three-dimensional perspective Multi-scale China

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A laser-engraved wearable gait recognition sensor system for exoskeleton robots

引用

Microsystems & Nanoengineering 2024年第2期10卷 269-277页

作者： Maowen Sun Songya Cui Zezheng Wang Huayu Luo Huayong Yang Xiaoping Ouyang Kaichen Xu State key laboratory of Fluid Power and Mechatronic Systems School of Mechanical EngineeringZhejiang UniversityHangzhou310027China School of information and Electrical Engineering Hangzhou City UniversityHangzhou310015China

As a reinforcement technology that improves load-bearing ability and prevents injuries,assisted exoskeleton robots have extensive applications in freight transport and health *** perception of gait information by such robots is vital for their *** information is the basis for motion planning in assistive and collaborative ***,a wearable gait recognition sensor system for exoskeleton robots is *** sensor arrays based on laser-induced graphene are developed with flexibility and *** sensor units are integrated into an insole to detect real-time pressure at key plantar *** addition,the circuit hardware and the algorithm are designed to reinforce the sensor system with the capability of gait *** experimental results show that the accuracy of gait recognition by the proposed system is 99.85%,and the effectiveness of the system is further verified through testing on an exoskeleton robot.

关键词： hardware robot skeleton

来源：

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

Gradient sparsification for efficient wireless federated learning with differential privacy

引用

science China(information sciences) 2024年第4期67卷 272-288页

作者： Kang WEI Jun LI Chuan MA Ming DING Feng SHU Haitao ZHAO Wen CHEN Hongbo ZHU School of Electronic and Optical Engineering Nanjing University of Science and Technology zhejiang Lab key laboratory of Computer Network and information Integration(Southeast University) Ministry of Education Data61 Commonwealth Scientific and Industrial Research Organisation School of information and Communication Engineering Hainan University School of Communications and information Engineering Nanjing University of Posts and Telecommunications School of Electronic information and Electrical Engineering Shanghai Jiao Tong University

Federated learning(FL) enables distributed clients to collaboratively train a machine learning model without sharing raw data with each other. However, it suffers from the leakage of private information from uploading models. In addition, as the model size grows, the training latency increases due to the limited transmission bandwidth and model performance degradation while using differential privacy(DP)protection. In this paper, we propose a gradient sparsification empowered FL framework with DP over wireless channels, to improve training efficiency without sacrificing convergence performance. Specifically, we first design a random sparsification algorithm to retain a fraction of the gradient elements in each client’s local model, thereby mitigating the performance degradation induced by DP and reducing the number of transmission parameters over wireless channels. Then, we analyze the convergence bound of the proposed algorithm, by modeling a non-convex FL problem. Next, we formulate a time-sequential stochastic optimization problem for minimizing the developed convergence bound, under the constraints of transmit power, the average transmitting delay, as well as the client’s DP requirement. Utilizing the Lyapunov drift-plus-penalty framework, we develop an analytical solution to the optimization problem. Extensive experiments have been implemented on three real-life datasets to demonstrate the effectiveness of our proposed algorithm. We show that our proposed algorithms can fully exploit the interworking between communication and computation to outperform the baselines, i.e., random scheduling, round robin, and delay-minimization algorithms.

关键词： federated learning differential privacy gradient sparsification Lyapunov drift convergence analysis

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Detecting fake reviewers in heterogeneous networks of buyers and sellers:a collaborative training-based spammer group algorithm

引用

Cybersecurity 2024年第2期7卷 44-67页

作者： Qi Zhang Zhixiang Liang Shujuan Ji Benyong Xing Dickson K.W.Chiu Shandong provincial key laboratory of Wisdom Mine information Technology Shandong University of Science and TechnologyQingdao 266590ShandongChina Zhejang University-University of linois at Urbana-Champaign Institute Haining 314499ZhejiangChina School of Civil Engineering Beijing Jiaotong UniversityBeijing 100044China Faculty of Education The University of Hong KongPok Fu LamHong KongChina

It is not uncommon for malicious sellers to collude with fake reviewers(also called spammers)to write fake reviews for multiple products to either demote competitors or promote their products'reputations,forming a gray industry *** detect spammer groups in a heterogeneous network with rich semantic information from both buyers and sellers,researchers have conducted extensive research using Frequent Item Mining-based and graph-based ***,these methods cannot detect spammer groups with cross-product attacks and do not jointly consider structural and attribute features,and structure-attribute correlation,resulting in poorer detection ***-fore,we propose a collaborative training-based spammer group detection algorithm by constructing a heterogene-ous induced sub-network based on the target product set to detect cross-product attack spammer *** jointly consider all available features,we use the collaborative training method to learn the feature representations of *** addition,we use the DBSCAN clustering method to generate candidate groups,exclude innocent ones,and rank them to obtain spammer *** experimental results on real-world datasets indicate that the overall detection performance of the proposed method is better than that of the baseline methods.

关键词： Spammer group Heterogeneous network Collaborative training DBSCAN

来源：

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

Ka-band thin film lithium niobate photonic integrated optoelectronic oscillator

引用

Photonics Research 2024年第6期12卷 1283-1293页

作者： RUI MA ZIJUN HUANG SHENGQIAN GAO JINGYI WANG XICHEN WANG XIAN ZHANG PENG HAO X.STEVE YAO XINLUN CAI State key laboratory of Optoelectronic Materials and Technologies School of Electronics and Information TechnologySun Yat-sen UniversityGuangzhou 510275China Photonics information Innovation Center and Hebei provincial Center for Optical Sensing College of Physics Science and TechnologyHebei UniversityBaoding 071002China NuVison Photonics Inc.Las VegasNevada 89109USA

Photonics integration of an optoelectronic oscillator(OEO)on a chip is attractive for fabricating low cost,compact,low power consumption,and highly reliable microwave sources,which has been demonstrated recently in silicon on insulator(SOI)and indium phosphide(InP)platforms at X-band around 8 *** we demonstrate the first integration of OEOs on the thin film lithium niobate(TFLN)platform,which has the advantages of lower Vπ,no chirp,wider frequency range,and less sensitivity to *** have successfully realized two different OEOs operating at Ka-band,with phase noises even lower than those of the X-band OEOs on SOI and InP *** is a fixed frequency OEO at 30 GHz realized by integrating a Mach–Zehnder modulator(MZM)with an add-drop microring resonator(MRR),and the other is a tunable frequency OEO at 20–35 GHz realized by integrating a phase modulator(PM)with a notch *** work marks the first step of using TFLN to fabricate integrated OEOs with high frequency,small size,low cost,wide range tunability,and potentially low phase noise.

关键词： optoelectronic modulator resonator

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

H-and J-aggregation of conjugated small molecules in organic solar cells

引用

Journal of Energy Chemistry 2024年第6期93卷 174-192,I0005页

作者： Qiaoqiao Zhao Feng He State key laboratory of Biobased Material and Green Papermaking Qilu University of TechnologyShandong Academy of SciencesJinan 250353ShangdongChina Shenzhen Grubbs Institute and Department of Chemistry Southern University of Science and TechnologyShenzhen 518055GuangdongChina Guangdong provincial key laboratory of Catalysis Southern University of Science and TechnologyShenzhen 518055GuangdongChina

As H-and J-aggregation receive more and more attention in the research of organic solar cells(OSCs),especially in small molecular systems,deep understanding of aggregation behavior is needed to guide the design of conjugated small molecular structure and the fabrication process of OSC *** this end,this review is ***,the review firstly introduced the basic information about H-and J-aggregation of conjugated small molecules in ***,the characteristics of H-and J-aggregation and the methods to identify them were ***,it reviewed the research progress of H-and J-aggregation of conjugated small molecules in OSCs,including the factors influencing H-and J-aggregation in thin film and the effects of H-and J-aggregation on OPV performance.

关键词： H-aggregation J-aggregation Organic solar cells Small molecules Efficiency Stability

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：