检索结果-南通市图书馆

Distributed active vibration control for helicopter based on diffusion collaboration

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第8期37卷 208-232页

作者： Yang YUAN Yang LU Xunjun ma Jingliang li Huiyu YUE National Key Laboratory of Helicopter Aeromechanics Nanjing University of Aeronautics and AstronauticsNanjing 210016China Wuhan Second Ship Design and Research Institute Wuhan 430205China

The active vibration control technology has been successfully applied to several helicopter ***,with the increasing of control scale,traditional centralized control algorithms are experiencing significant increase of computational complexity and physical implementation *** address this issue,a diffusion collaboration-based distributed Filtered-x Least Mean Square algorithm applied to active vibration control is proposed,drawing inspiration from the concept of data fusion in wireless sensor *** algorithm distributes the computation load to each node,and constructs the active vibration control network topology of large-scale system by discarding the weak coupling secondary paths between nodes,achieving distributed active vibration *** order to thoroughly validate the effectiveness and superiority of this algorithm,a helicopter fuselage model is designed as the research ***,the excellent vibration reduction performance of the proposed algorithm is confirmed through ***,specialized node control units are developed,which utilize STM32 microcontroller as the processing ***,a distributed control system is constructed based on multi-processor *** on this foundation,a large-scale active vibration control experimental platform is *** on the platform,experiments are carried out,involving the 4-input 4-output system and the 8-input 8-output *** experimental results demonstrate that under steady-state harmonic excitation,the proposed algorithm not only ensures control effectiveness but also reduces computational complexity by 50%,exhibiting faster convergence speed compared with traditional centralized *** time-varying external excitation,the proposed algorithm demonstrates rapid tracking of vibration changes,with vibration amplitudes at all controlled points declining by over 94%,proving the strong robustness and adaptive capability of the algorithm

关键词： Helicopter Active vibration control Diffusion collaboration Distributed control Experiment

Automatic recognition of landslides based on YOLOv7 and attention mechanism

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 Mountain Science 2024年第8期21卷 2681-2695页

作者： SONG Yewei GUO Jie WU Gaofeng ma Fengshan li Fangrui Key Laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for Earth Sciences Chinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China

Landslide disasters comprise the majority of geological incidents on slopes,posing severe threats to the safety of human lives and property while exerting a significant impact on the geological *** rapid identification of landslides is important for disaster prevention and control;however,currently,landslide identification relies mainly on the manual interpretation of remote sensing *** interpretation and feature recognition methods are time-consuming,labor-intensive,and challenging when confronted with complex ***,automatic landslide recognition has emerged as a pivotal avenue for future *** this study,a dataset comprising 2000 landslide images was constructed using open-source remote sensing images and *** YOLOv7 model was enhanced using data augmentation algorithms and attention *** optimization models were formulated to realize automatic landslide *** findings demonstrate the commendable performance of the optimized model in automatic landslide recognition,achieving a peak accuracy of 95.92%.Subsequently,the optimized model was applied to regional landslide identification,co-seismic landslide identification,and landslide recognition at various scales,all of which showed robust recognition ***,the model exhibits limitations in detecting small targets,indicating areas for refining the deep-learning *** results of this research offer valuable technical support for the swift identification,prevention,and mitigation of landslide disasters.

关键词： Deep learning Landslide detection Natural disasters Attention mechanism Remote sensing

Grain size and surface micro-texture characteristics and their paleoenvironmental significance of Holocene sediment in southern margin of the Gurbantunggut Desert,China

在线全文

学校读者我要写书评

暂无评论

Journal of Arid Land 2024年第5期16卷 632-653页

作者： ma Yunqiang li Zhizhong TAN Dianjia ZOU Xiaojun TAO Tonglian School of Geographical Sciences Fujian Normal UniversityFuzhou 350117China Key Laboratory for Humid Subtropical Eco-geographical Processes of the Ministry of Education Fujian Normal UniversityFuzhou 350117China Institute of Geography Fujian Normal UniversityFuzhou 350117China

The southern margin of the Gurbantunggut Desert,China,is characterized by alternating layers of aeolian and alluvial *** the characteristics of arenaceous sediment in this area is of significant importance for understanding the interactive processes of wind and water forces,as well as the provenance of ***,there are relatively few investigations on the characteristics of such sediment at *** this study,we researched three aeolian-alluvial interactive stratigraphic profiles and different types of surface sediment on the desert-oasis transitional zone of southern margin of the Gurbantunggut *** on the optically stimulated luminescence(OSL)dating of aeolian sand and analyses of quartz sand grain size and surface micro-texture,we explored the aeolian-alluvial environmental change at southern margin of the desert in Holocene,as well as the provenance of *** results indicated that the grain size characteristics of different types of sediment in the stratigraphic profiles were similar to those of modern dune sand,interdune sand,muddy desert surface soil,and riverbed *** frequency curves were unimodal or bimodal,and cumulative probability curves were two-segment or three-segment,mainly composed of suspension load and saltation *** quartz sand in the sediment at southern margin of the desert had undergone alternating transformation of various exogenic forces,with short transportation distance and time,and sedimentary environment was relatively *** Holocene,southern margin of the desert primarily featured braided river deposits,and during intermittent period of river activity,there were also aeolian deposits such as sand sheet deposits,stabilized dune deposits,and mobile dune *** provenance for Holocene alluvial deposits at southern margin of the desert remains relatively constant,with the debris of the Tianshan Mountains being the primary *** sand is mainly near-source recharge,

关键词： aeolian-alluvial deposition grain size surface micro-texture sedimentary environment Holocene

Optimal search path planning of UUV in battlefeld ambush scene

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第2期32卷 541-552页

作者： Wei Feng Yan ma Heng li Haixiao liu Xiangyao Meng Mo Zhou Naval Research Institute Beijing100161China

Aiming at the practical application of Unmanned Underwater Vehicle(UUV)in underwater combat,this paper proposes a battlefield ambush scene with UUV considering ocean ***,by establishing these mathematical models of ocean current environment,target movement,and sonar detection,the probability calculation methods of single UUV searching target and multiple UUV cooperatively searching target are given ***,based on the Hybrid Quantum-behaved Particle Swarm Optimization(HQPSO)algorithm,the path with the highest target search probability is ***,through simulation calculations,the influence of different UUV parameters and target parameters on the target search probability is analyzed,and the minimum number of UUVs that need to be deployed to complete the ambush task is demonstrated,and the optimal search path scheme is *** method proposed in this paper provides a theoretical basis for the practical application of UUV in the future combat.

关键词： Battlefield ambush Optimal search path planning UUV path Planning Probability of cooperative search

Prevalence and risk factors of diabetes mellitus among elderly patients in the Lugu community

在线全文

学校读者我要写书评

暂无评论

World Journal of Diabetes 2024年第4期15卷 638-644页

作者： li-Zhen Zhao Wei-Min li Ying ma Lugu Community Health Service Center West Campus Beijing Chao-yang Hospital Affiliated to Capital Medical UniversityBeijing 100043China

BACKGROUND Age is a significant risk factor of diabetes mellitus(DM).With the develop of population aging,the incidence of DM remains *** the epidemiology of DM among elderly individuals in a certain area contributes to the DM interventions for the local elderly individuals with high risk of *** To explore the prevalence of DM among elderly individuals in the Lugu community and analyze the related risk factors to provide a valid scientific basis for the health management of elderly *** A total of 4816 elderly people who came to the community for physical examination were retrospectively *** prevalence of DM among the elderly was *** individuals were divided into a DM group and a non-DM group according to the diagnosis of DM to compare the differences in diastolic blood pressure(DBP)and systolic blood pressure(SBP),fasting blood glucose,body mass index(BMI),waist-to-hip ratio(WHR)and incidence of hypertension(HT),coronary heart disease(CHD),and chronic kidney disease(CKD).RESULTS DM was diagnosed in 32.70%of the 4816 elderly *** BMI of the DM group(25.16±3.35)was greater than that of the non-DM group(24.61±3.78).The WHR was 0.90±0.04 in the non-DM group and 0.90±0.03 in the DM group,with no significant *** left SBP and SBP in the DM group were 137.9 mmHg±11.92 mmHg and 69.95 mmHg±7.75 mmHg,respectively,while they were 126.6 mmHg±12.44 mmHg and 71.15 mmHg±12.55 mmHg,respectively,in the non-DM *** findings indicate higher SBP and lower DBP in DM patients than in those without *** the DM group,1274 patients were diagnosed with HT,accounting for 80.89%.Among the 3241 non-DM patients,1743(53.78%)were hypertensive and 1498(46.22%)were *** DM group had more cases of HT than did the non-DM *** were more patients with CHD or CKD in the DM group than in the non-DM *** were more patients who drank alcohol more frequently(≥3 times)in the DM group than in the no

关键词： Diabetes mellitus Type 2 diabetes mellitus Elderly Risk factors

Analysis of Tidal Current Energy Potential in the major Channels of the Bohai Strait Based on Delft3D

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 Ocean University of China 2024年第4期23卷 859-870页

作者： ma Pengcheng SHI Hongyuan XUE Huaiyuan li Pingping SUN Yongkang School of Hydraulic Engineering Ludong University of ChinaYantai 264025China Institute of Coastal Research Ludong University of ChinaYantai 264025China Yantai Kekan marine Technology Co. Ltd.Yantai 264025China

The utilization and development of tidal current energy can help alleviate the current energy shortage,improve the global ecological environment,and maintain sustainable *** this study,numerical simulation is carried out on a rectangular grid using *** tidal current energy potential of the major channels in the Bohai Strait is further simulated and estimated by comparing the simulated and measured *** show that the flow module in Delft3D has good modeling ability for the assessment of tidal current energy *** average flow velocity,maximum flow velocity,and energy flow density are *** Laotieshan Channel,located in the northern part of the Bohai Strait,shows a large tidal current energy *** maximum flow velocity of this channel can reach 2 m s-1,and the maximum energy flow density can exceed 500 W *** tidal current energy in the Laotieshan Channel is more than 10 times that in other ***,this study advocates for the continued exploration and exploitation of the tidal current energy resources in the Laotieshan Channel.

关键词： Delft3D Bohai Strait tidal current energy numerical simulation power density

Experimental Investigation on Solution Regeneration Performance and Coefficients in Full-Open System for Heat and Water Recovery of Flue Gas

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2024年第3期33卷 1094-1108页

作者： WEI Hongyang HUANG Shifang ma Yuxin CHEN Bo SUN li ZHANG Xiaosong School of Energy and Environment Southeast UniversityNanjing210096China MOE Engineering Research Center for Building Energy Equipment&Environment Southeast UniversityNanjing210096China Jiangsu Frontier Electric Technology Co. LtdNanjing211106China

The recovery of heat and water from low-grade flue gas is of considerable importance for energy conservation and environmental *** the full-open absorption heat pump shows promise as a means of achieving heat and water recovery,the lack of research on heat and mass transfer performance of open-type solution evaporation regeneration represents a significant impediment to its design and *** paper experimentally investigates the regeneration performance of an open-type spaying tower equipped with ceramic structured *** different regeneration modes are proposed,namely ambient air receiver mode and flue gas receiver mode,to utilize air or low-grade flue gas as a driving *** impact of different input parameters on the regeneration characteristics,including heat transfer capacity,water removal rate,thermal efficiency,and humidity effectiveness,are *** findings indicate that the enhancement of regeneration can be achieved through the increase of solution flow rate,solution temperature,and flue gas flow rate in both regeneration ***,high solution concentration and flue gas humidity ratio can weaken water removal rates and reduce thermal *** the regeneration of CaCl_(2)-H_(2)O with a concentration of55%,flue gas around 200℃with a humidity ratio below 44 g/kg can successfully drive the solution regeneration *** the solution concentration or flue gas humidity ratio continues to rise,additional energy is necessary for ***,the coupled heat and mass transfer coefficients are fitted,which can contribute to the design and optimization of the open-type regenerator.

关键词： heat and water recovery solution regeneration flue gas regeneration performance coefficient

Health risks and sources of trace elements and black carbon in PM_(2.5)from 2019 to 2021 in Beijing

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第8期142卷 69-82页

作者： Chenjie Hua Wei ma Feixue Zheng Yusheng Zhang Jiali Xie li ma Boying Song Chao Yan Hongyan li Zhen liu Qian liu markku Kulmala Yongchun liu Aerosol and Haze Laboratory Advanced Innovation Center for Soft Matter Science and EngineeringBeijing University of Chemical TechnologyBeijing 100029China Institute for Atmospheric and Earth System Research Faculty of ScienceUniversity of HelsinkiHelsinki 00014Finland School of Environment and Safety Taiyuan University of Science and TechnologyTaiyuan 030024China State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China

A comprehensive health risk assessment of PM_(2.5)is meaningful to understand the current status and directions regarding further improving air quality from the perspective of human *** this study,we evaluated the health risks of PM_(2.5)as well as highly toxic inorganic components,including heavy metals(HMs)and black carbon(BC)based on longterm observations in Beijing from 2019 to *** results showed that the relative risks of chronic obstructive pulmonary disease,lung cancer,acute lower respiratory tract infection,ischemic heart disease,and stroke decreased by 4.07%-9.30%in 2020 and 2.12%-6.70%in2021 compared with ***,they were still at high levels ranging from 1.26 to 1.77,in particular,stroke showed the highest value in *** had the highest hazard quotient(HQ,from 2.18 to 2.56)for adults from 2019 to 2021,while Ni,Cr,Pb,As,and BC showed high carcinogenic risks(CR>1.0×10^(-6))for *** HQ values of Mn and As and the CR values of Pb and As showed constant or slight upwards trends during our observations,which is in contrast to the downward trends of other HMs and PM_(2.5).Mn,Cr,and BC are crucial toxicants in PM_(2.5).A significant shrink of southern region sourcesof HMs and BCshrank suggests the increased importance of local ***,dust,and biomass burning are the major contributors to the non-carcinogenic risks,while traffic emissions and industry are the dominant contributors to the carcinogenic risks in Beijing.

关键词： PM_(2.5) Heavy metals Black carbon Health risk Source apportionment

Insulation Design Rule for a Spacer in SF_(6)/N_(2)-filled DC Gas Insulated Apparatus

在线全文

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2024年第2期10卷 727-735页

作者： Hongyang Zhou Guoming ma Meng Zhang Cong wang Youping Tu Chengrong li State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources and the Beijing Key Laboratory of High Voltage and EMC North China Electric Power UniversityBeijing 102206China

A recurring challenge of a DC SF_(6)/N_(2)-filled GIS/GIL apparatus is the charge accumulation at DC *** conventional design rules and knowledge of AC spacers may not be applicable for this new type of apparatus.A novel design rule is proposed considering the effect of accumulated charge on the threshold of electric field strength being resistant to the superposed voltage.A surface charge accumulation simulation model is introduced,and the key parameters in the simulation model are *** addition,an experimental platform for a 100 kV spacer flashover test is *** flashover tests under superimposed voltage with opposing polarities are carried out,and the withstanding voltage of the spacer is ***,based on the proposed model,the threshold of the surface electric field strength(tangential component)on the DC spacer in SF_(6)/N_(2) mixed gases is *** a reliable insulation design of a DC GIS/GIL apparatus filled with 0.7 MPa SF_(6)/N_(2),the threshold of surface electric field strength on the DC spacer is 12 kV/*** insulation design rule can be referenced in the design of a high-voltage DC SF_(6)/N_(2)-filled GIS/GIL apparatus.

关键词： Charge accumulation DC spacer flashover voltage SF_(6)/N_(2) threshold of surface electric field strength