检索结果-南通市图书馆

A Modified Iterative Learning Control Approach for the Active Suppression of Rotor Vibration Induced by Coupled Unbalance and Misalignment

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2024年第1期37卷 242-253页

作者： Yifan Bao Jianfei Yao Fabrizio Scarpa Yan Li College of Mechanical and Electrical Engineering Beijing University of Chemical TechnologyBeijing 100029China State Key Laboratory of High-end Compressor and System Technology Beijing 100029China Beijing Key Laboratory of High-end Mechanical Equipment Health Monitoring and Self-Recovery Beijing University of Chemical TechnologyBeijing 100029China Key Lab of Engine Health Monitoring-Control and Networking of Ministry of Education Beijing University of Chemical TechnologyBeijing 100029China bristol Composites Institute(ACCIS) University of BristolBristol BS81TRUK Dynamics and Control Research Group(DCRG) University of BristolBristol BS81TRUK

This paper proposes a modified iterative learning control(MILC)periodical feedback-feedforward algorithm to reduce the vibration of a rotor caused by coupled unbalance and parallel *** control of the vibration of the rotor is provided by an active magnetic actuator(AMA).The iterative gain of the MILC algorithm here presented has a self-adjustment based on the magnitude of the *** filters are adopted to extract the synchronous(1×Ω)and twice rotational frequency(2×Ω)components of the rotor *** the notch frequency of the filter and the size of feedforward storage used during the experiment have a real-time adaptation to the rotational *** method proposed in this work can provide effective suppression of the vibration of the rotor in case of sudden changes or fluctuations of the rotor *** and experiments using the MILC algorithm proposed here are carried out and give evidence to the feasibility and robustness of the technique proposed.

关键词： Rotor vibration suppression Modified iterative learning control Unbalance Parallel misalignment Active magnetic actuator

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

基于CNF的饱和切换系统的事件触发控制

控制与决策 2024年第8期39卷 2631-2636页

作者：王娟朱帅东朱全民沈阳建筑大学电气与控制工程学院沈阳110168 西英格兰大学工程设计与数学系布鲁斯托尔BS161QY

针对一类具有执行器饱和的切换系统,提出一种基于组合非线性反馈控制(CNF)的事件触发控制方法,以达到在保证系统性能的同时减少网络带宽占用的目的.首先,为了降低系统资源成本,构造事件触发机制来判断是否对系统当前状态进行采样,设计... 详细信息

针对一类具有执行器饱和的切换系统,提出一种基于组合非线性反馈控制(CNF)的事件触发控制方法,以达到在保证系统性能的同时减少网络带宽占用的目的.首先,为了降低系统资源成本,构造事件触发机制来判断是否对系统当前状态进行采样,设计组合非线性反馈控制来提高系统的暂态性能;然后,利用多Lyapunov函数方法得到饱和切换系统在驻留时间切换信号下渐近跟踪问题的充分条件,同时证明事件触发最小的时间间隔大于零,从而避免芝诺(Zeno)行为;最后,通过仿真实例验证所提出方法的有效性.

关键词：饱和切换系统事件触发控制组合非线性反馈驻留时间渐近跟踪

Induction of defence gene expression by oligogalacturonic acid requires in- creases in both cytosolic calcium and hydrogen peroxide in Arabidopsis thaliana

在线全文

学校读者我要写书评

暂无评论

Cell Research 2004年第3期14卷 234-240页

作者： Steven J NEILL Centre for Research in Plant Science University of the West of England bristol Coldharbour Lane bristol bs16 1qy UK

Responses to oligogalacturonic acid （OGA） were determined in transgenic Arabidopsis thaliana seedlings expressing the calcium reporter protein aequorin. OGA stimulated a rapid, substantial and transient increase in the concentration of cytosolic calcium （[Ca2+]cyt） that peaked after ca. 15 s. This increase was dose-dependent, saturating at ca. 50 μg Gal equiv/ml of OGA. OGA also stimulated a rapid generation of H2O2. A small, rapid increase in H2O2 content was followed by a much larger oxidative burst, with H2O2 content peaking after ca. 60 min and declining thereafter. Induction of the oxidative burst by OGA was also dose-dependent, with a maximum response again being achieved at ca. 50 μg Gal equiv/mL. Inhibitors of calcium fluxes inhibited both increases in [Ca2+]cyt and [H2O2], whereas inhibitors of NADPH oxidase blocked only the oxidative burst. OGA increased strongly the expression of the defence-related genes CHS, GST, PAL and PR-1. This induction was suppressed by inhibitors of calcium flux or

关键词： Arabidopsis thaliana cytosolic calcium defence gene expression hydrogen peroxide OGA.

From Teleoperation to Autonomous Robot-assisted Microsurgery:A Survey

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Machine Intelligence Research 2022年第4期19卷 288-306页

作者： Dandan Zhang Weiyong Si Wen Fan Yuan Guan Chenguang Yang Department of Engineering Mathematics University of BristolBristol BS81THUK Department of Engineering Design and Mathematics University of the West of EnglandBristol BS161QYUK bristol Robotics Laboratory Bristol BS161QYUK

Robot-assisted microsurgery(RAMS)has many benefits compared to traditional *** platforms with advanced control strategies,high-quality micro-imaging modalities and micro-sensing systems are worth developing to further enhance the clinical outcomes of *** only a few decades,microsurgical robotics has evolved into a rapidly developing research field with increasing attention all over the *** the appreciated benefits,significant challenges remain to be *** this review paper,the emerging concepts and achievements of RAMS will be *** introduce the development tendency of RAMS from teleoperation to autonomous *** highlight the upcoming new research opportunities that require joint efforts from both clinicians and engineers to pursue further outcomes for RAMS in years to come.

关键词： Robot-assisted microsurgery(RAMS) imaging and sensing teleoperation cooperative control robot learning.

Bio-Imitation of Mexican Migration Routes to the USA with Slime Mould on 3D Terrains

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic Engineering 2013年第2期10卷 242-250页

作者： Andrew Adamatzky Genaro J Martinez Department of Computer Sciences University of the West of England Bristol BS16 1QY UK Escuela Superior de Computo Instituto Politecnico Nacional Mexico

Plasmodium ofPhysarum polycephalum （P. polycephalum） is a large single cell visible by an unaided eye. It shows sophisticated behavioural traits in foraging for nutrients and developing an optimal transport network of protoplasmic tubes spanning sources of nutrients. When placed in an environment with distributed sources of nutrients the cell computes＇ an optimal graph spanning the nutrients by growing a network of protoplasmic tubes. P. polycephalum imitates development ofman-made transport networks of a country when configuration of nutrients represents major urban areas, We employed this feature of the slime mould to imitate mexican migration to USA. The Mexican migration to USA is the World＇s larger migration system. We bio-physically imitated the migration using slime mould P. poIycephalum. In laboratory experiments with 3D Nylon terrains of USA we imitated development of migratory routes from Mexico-USA border to ten urban areas with high concentration of Mexican migrants. From results of laboratory experiments we extracted topologies of migratory routes, and highlighted a role of elevations in shaping the human movement networks.

关键词： biomimetics bio-inspired computing migration routes slime mould

The use of fine portions from construction and demolition waste for expansive soil stabilization: A review

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2022年第7期16卷 803-816页

作者： Mgboawaji Claude UJILE Samuel Jonah ABBEY Civil Engineering Faculty of Environment and TechnologyUniversity of the West of EnglandBristol BS161QYUK Geotechnical Engineering Faculty of Environment and TechnologyUniversity of the West of EnglandBristol BS161QYUK

Construction and demolition waste(CDW)are the largest waste products in the world today and competes as a viable recycled additive material in place of natural *** to the increase in compressive strength of different mix proportions of CDW,it is also considered for reuse in concrete and subbase *** study shows the effect of CDW in expansive soil *** chemical and mechanical properties of these materials have shown that they are capable of developing compressive strength properties for replacement of cement with significant reduction in carbon *** inherent compositional properties of recycled CDW compared in this review suggests that CDW have good filler properties in highly expansive *** of crushed brick and recycled aggregates characterised based on chemical properties of different replacement ratios suggests that CDW of good-quality aggregates reduces swell potential of expansive soils and increased mechanical strength in pavement construction.

关键词： mixed fine portions construction and demolition waste expansive soil soil stabilization

在线全文

学校读者我要写书评

暂无评论

结构未知系统降维辨识方法——变量消去算法

控制与决策 2024年第1期39卷 171-179页

作者：陈晶程连元李俊红朱全民江南大学理学院江苏无锡214122 南通大学电气工程学院江苏南通226019 西英格兰大学工业设计和数学系英国布里斯托BS161QY

针对结构未知的系统提出一种新的降维辨识方法.借助核函数方法,利用一个高维Volterra模型逼近未知系统.由于Volterra模型未知参数维数较高,为避免高阶矩阵求逆和求特征值,提出变量消去算法,将高维系统的辨识问题转化为两个低维系统辨识... 详细信息

针对结构未知的系统提出一种新的降维辨识方法.借助核函数方法,利用一个高维Volterra模型逼近未知系统.由于Volterra模型未知参数维数较高,为避免高阶矩阵求逆和求特征值,提出变量消去算法,将高维系统的辨识问题转化为两个低维系统辨识问题.通过理论证明采用降维算法后降维系统信息矩阵条件数变小,参数收敛速度得到提高.进一步引入Aitken加速方法提高算法收敛速度,增强算法对步长的鲁棒特性.最后通过仿真例子验证所提出方法的有效性.

关键词：参数估计降维算法变量消去算法 Volterra模型结构未知系统矩阵条件数

Specialized springtail predation by Loricera beetles: An example of evolutionary stasis across the K-Pg extinction

在线全文

学校读者我要写书评

暂无评论

The Innovation 2024年第3期5卷 25-26页

作者： Yan-Da Li Erik Tihelka Michael SEngel Diying Huang Chenyang Cai State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and PalaeontologyChinese Academy of SciencesNanjing 210008China Department of Earth Sciences University of CambridgeCambridge CB23EQUK bristol Palaeobiology Group School of Earth SciencesUniversity of BristolBristol BS81TQUK Division of Invertebrate Zoology American Museum of Natural HistoryNew YorkNY 10024-5192USA Facultad de Ciencias Biológicas Universidad Nacional Mayor de San MarcosLima 15081Perú Departamento de Entomología Museo de Historia NaturalUniversidad Nacional Mayor de San MarcosLima 15072Perú

Dear Editor,The Cretaceous-Paleogene(K-Pg)mass extinction precipitated one of the most profound restructurings of biodiversity in recent geological *** the extinction of many iconic groups,particularly the non-avian dinosaurs,there is emerging evidence that previously overlooked taxa experienced stark morphological and evolutionary *** this study,we report both adult and larva of beetles of the genus Loricera preserved in mid-Cretaceous Kachin amber(Figure 1),which display striking similarity to extant congeners,indicating a stasis of their specialized feeding behavior persisting at least 100 million years.

关键词： extinction Figure Cretaceous

Impacts of Water-Sediment Regulation Scheme on Chromophoric Dissolved Organic Matter in the Lower Yellow River

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2期23卷 455-466页

作者： LIU Xiao JIANG Xueyan LIU Qian SUI Juanjuan ZOU Li Key Laboratory of Marine Chemistry Theory and Technology of Ministry of Education Ocean University of ChinaQingdao 266100China College of Chemistry and Chemical Engineering Ocean University of ChinaQingdao 266100China School of Earth Sciences University of BristolBristolBS81RJUK North China Sea Environmental Monitoring Center State Oceanic AdministrationQingdao 266033China Key Laboratory of Ecological Prewarning Protection and Restoration of Bohai SeaMinistry of Natural ResourcesQingdao 266033China Key Laboratory of Marine Environment and Ecology of Ministry of Education Ocean University of ChinaQingdao 266100China College of Environmental Science and Engineering Ocean University of ChinaQingdao 266100China

As a river with more than 3000 reservoirs in its watershed,the Yellow River has been affected by dams not only on the sediment load,but also on the water ***-sediment regulation scheme(WSRS),which has been carried out annually in the Yellow River since 2002,is a typical human activity affecting river water *** dissolved organic matter(CDOM)in river is susceptible to changes in ecological and environmental conditions as well as human ***,we report variations in dissolved organic carbon concentrations,compositions and sources of CDOM in time series samples in the lower Yellow River during *** addition,a parallel factor fluorescence analysis(PARAFAC)method is applied to identify different fluorescent components in water samples during WRSR,showing four major components including tryptophan-like component(C1),microbial humic-like component(C2),terrestrial humic-like component(C3)and tyrosine-like component(C4).In general,C1 increased after water regulation,while C2 and C3 increased after sediment regulation,indicating that the water and sediment released by the dam have different effects on CDOM *** the impacts of the dam,source of CDOM in the lower Yellow River is mainly autochthonous related to microbial activities,and is regulated by the terrestrial input during WSRS *** resuspension inhibits microbial activities and reduces the production of autochthonous ***,human activities especially WSRS,as exemplified here,significantly alter the quality and quantity of CDOM in the lower Yellow River,affecting CDOM dynamics and biogeochemical processes in the estuarine environment.

关键词： chromophoric dissolved organic matter(CDOM) water-sediment regulation scheme(WSRS) Yellow River optical properties