检索结果-南通市图书馆

Design of distributed dynamic absorbers for vibration suppression of panel structures

Acta Mechanica Sinica 2024年第7期40卷 164-180页

作者： liyuan li bin li Zehua Xu School of Aeronautics Northwestern Polytechnical UniversityXi'an 710072China China Aero-Polytechnology Establishment Beijing 100028China

Distributed dynamic absorbers have many advantages such as wide frequency bandwidth for vibration suppression,strong detuning adaptability,and high system stability,making them very suitable for the vibration and noise control of continuous ***,they have broad application prospects in various fields such as transportation,aviation,and ***,there are still many challenges in the engineering applications of distributed dynamic absorbers for vibration suppression,including the engineering realization of the optimal damping of traditional optimal coherence dynamic absorbers,and the engineering applicability of the finite periodic array dynamic *** on the damping material properties obtained by the dynamic mechanical analyzer tests,this paper establishes the finite element model of the cantilever-beam-type dynamic absorber with constrained damping layers,aiming to realize the accurate determination of the optimal *** are conducted by attaching the traditional dynamic absorbers with the optimal damping to a thin-walled panel with four clamped *** show that the vibration of the panel is well suppressed,with the reduction of the frequency response peak larger than 14 dB and the reduction ratio of RMS larger than 58%within 500 ***,the periodically arrayed dynamic absorbers are designed according to the bandgap regulation *** tuning behavior of the arrayed dynamic absorbers by changing designing parameters is *** vibration reduction effect of arrayed dynamic absorbers is compared with that of the traditional dynamic absorbers under the same mass ratio through *** indicate that the arrayed dynamic absorbers are easier to design,and have a similar reduction effect on the modal vibration of the thin panel as the traditional dynamic absorbers within a narrow frequency range near the natural frequency,while they perform unsatisfactory in a broad ***,if t

关键词： Distributed dynamic absorbers Engineering realization of the optimal damping Vibration suppression Low-frequency and broadband

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

Dynamic Vision-Based Machinery Fault Diagnosis With Cross-Modality Feature Alignment

引用

IEEE/CAA Journal of Automatica Sinica 2024年第10期11卷 2068-2081页

作者： Xiang li Shupeng Yu Yaguo Lei Naipeng li bin Yang Key Laboratory of Education Ministry for Modern Design and Rotor-Bearing System Xi’an Jiaotong UniversityXi’an 710049China IEEE

Intelligent machinery fault diagnosis methods have been popularly and successfully developed in the past decades,and the vibration acceleration data collected by contact accelerometers have been widely *** many industrial scenarios,contactless sensors are more *** event camera is an emerging bio-inspired technology for vision sensing,which asynchronously records per-pixel brightness change polarity with high temporal resolution and low *** offers a promising tool for contactless machine vibration sensing and fault ***,the dynamic vision-based methods suffer from variations of practical factors such as camera position,machine operating condition,***,as a new sensing technology,the labeled dynamic vision data are limited,which generally cannot cover a wide range of machine fault *** at these challenges,a novel dynamic vision-based machinery fault diagnosis method is proposed in this *** is motivated to explore the abundant vibration acceleration data for enhancing the dynamic vision-based model performance.A crossmodality feature alignment method is thus proposed with deep adversarial neural networks to achieve fault diagnosis knowledge *** event erasing method is further proposed for improving model robustness against *** proposed method can effectively identify unseen fault mode with dynamic vision *** on two rotating machine monitoring datasets are carried out for validations,and the results suggest the proposed method is promising for generalized contactless machinery fault diagnosis.

关键词： Condition monitoring domain generalization eventbased camera fault diagnosis machine vision

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

Quaternary Activity Characteristics and Regional Tectonic Significance of the Jiulong Fault in Jiujiang,Jiangxi Province,China

引用

Journal of Earth Science 2024年第4期35卷 1107-1117页

作者： Xin Qi Yuyong Jiao Qinghua li bin li Faculty of Engineering China University of GeosciencesWuhan430074China Wuhan Center China Geological SurveyWuhan430205China Institute of Geological Survey China University of GeosciencesWuhan430074China

Obtaining geological and landform dislocation features,as well as the measured stratigraphic activity age,provides direct evidence to evaluate fault activity,which is more difficult to do in areas with low tectonic activity,such as eastern and central China.A detailed investigation of the fault activity,trenching,drilling joint geological profile,geological survey,and chronological analysis were used to obtain the spatial geometry,fault kinematics,and activity chronology of the Jiulong *** conclusions are as follows:(1)The Jiulong fault was a fracture zone composed of four branch faults,with a width of around 30–40 m and good extendibility,while the maximum surface rupture length was 373 m.(2)The Jiulong fault has many strata dislocations,and the dislocation distance decreased from bottom to top,demonstrating synsedimentary structure characteristics,with a maximum stratigraphic dislocation distance of 18.2 m.(3)Preliminary analysis suggested the Jiulong fault as a secondary fracture of the Xiangfan-Guangji fault zone and provided evidence of the southeastward extension of the Xiangfan-Guangji fault.A preliminary hypothesis purported the Xiangfan-Guangji fault as the seismogenic fault of the Ms 5.0 magnitude earthquake in 1911.(4)According to OSL and ESR dating analyses,the upper breakpoint of the Jiulong fault cuts into the Late Pleistocene Xingang Formation(Qp3x)strata,and the latest active age of the Jiulong fault was 57.6 *** chronology analysis confirmed an active fault from the Late Pleistocene and identified a weak tectonic in Jiujiang Province,which represents the largest active fault outcrop uncovered in the area so *** study provides evidence and research materials for the evaluation of fault activity and seismic stability in this region.

关键词： active fault regional tectonic earthquakes seismic intensity tectonics

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

Photosynthetic response dynamics in the invasive species Tithonia diversifolia and two co-occurring native shrub species under fluctuating light conditions

引用

Plant Diversity 2024年第2期46卷 265-273页

作者： Ju li Shu-bin Zhang Yang-Ping li CAS Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMenglunMengla 666303YunnanChina University of Chinese Academy of Sciences Beijing 100049China

To determine the invasiveness of invasive plants,many studies have compared photosynthetic traits or strategies between invasive and native ***,few studies have compared the photosynthetic dynamics between invasive and native species during light *** compared photosynthetic induction,relaxation dynamics and leaf traits between the invasive species,Tithonia diversifolia and two native species,Clerodendrum bungei and Blumea balsamifera,in full-sun and shady *** photosynthetic dynamics and leaf traits differed among *** showed a slower induction speed and stomatal opening response but had higher average intrinsic water-use efficiency than the two native species in full-sun ***,the slow induction response may be attributed to the longer stomatal length in *** had a significant effect on photosynthetic dynamics in *** and *** but not in *** shady habitat,*** had a faster photosynthetic induction response than in full-sun habitat,leading to a higher average stomatal conductance during photosynthetic induction in *** than in the two native *** contrast,*** had a larger stomatal length and slower photosynthetic induction and relaxation response in shady habitat than in full-sun habitat,resulting in higher carbon gain during photosynthetic ***,in both habitats,*** had an overall higher carbon gain during light fluctuations than the two native *** results indicated that *** can adopt more effective response strategies under fluctuating light environments to maximize carbon gain,which may contribute to its successful invasion.

关键词： Invasive plant Photosynthetic induction Photosynthetic relaxation Carbon gain Stomatal traits Tithonia diversifolia

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

SAC-Based Computation Offloading for Reconfigurable Intelligent Surface-Aided Mobile Edge Networks

引用

China Communications 2024年第6期21卷 261-270页

作者： li bin Qian Zhen Fei Zesong School of Computer Science Nanjing University of Information Science&TechnologyNanjing 210044China Jiangsu Collaborative Innovation Center of Atmospheric Environment and Equipment Technology(CICAEET) Nanjing University of Information Science&TechnologyNanjing 210044 School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China

In this paper,we concentrate on a reconfigurable intelligent surface(RIS)-aided mobile edge computing(MEC)system to improve the offload efficiency with moving user equipments(UEs).We aim to minimize the energy consumption of all UEs by jointly optimizing the discrete phase shift of RIS,UEs’transmitting power,computing resources allocation,and the UEs’task offloading strategies for local computing and *** formulated problem is a sequential decision making across multiple coherent time ***,the mobility of UEs brings uncertainties into the decision-making *** cope with this challenging problem,the deep reinforcement learning-based Soft Actor-Critic(SAC)algorithm is first proposed to effectively optimize the discrete phase of RIS and the UEs’task offloading ***,the transmitting power and computing resource allocation can be determined based on the *** results demonstrate that the proposed algorithm can be trained more stably and perform approximately 14%lower than the deep deterministic policy gradient benchmark in terms of energy consumption.

关键词： MEC RIS soft actor-critic user mobility

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

Distinct but correct: generating diversified and entity-revised medical response

引用

Science China(Information Sciences) 2024年第3期67卷 94-113页

作者： bin li bin SUN Shutao li Encheng CHEN Hongru liU Yixuan WENG Yongping BAI Meiling HU College of Electrical and Information Engineering Hunan University School of Mathematics Sun Yat-sen University JD Technology National Laboratory of Pattern Recognition Institute of AutomationChinese Academy of Sciences Xiangya Hospital of Central South University Teaching and Research Section of Clinical Nursing Xiangya Hospital of Central South University

Medical dialogue generation(MDG) is applied for building medical dialogue systems for intelligent consultation. Such systems can communicate with patients in real time, thereby improving the efficiency of clinical diagnosis. However, predicting correct entities and correctly generating distinct responses remain a great challenge. Inspired by actual doctors’ responses to patients, we consider MDG a two-stage task: entity prediction and dialogue generation. For entity prediction, we design an ent-mac post pre-training strategy by leveraging external medical entity knowledge to enhance the pre-trained model. For dialogue generation, we propose an entity-aware fusion MDG method in which predicted entities are integrated into the dialogue generation model through different encoding fusion mechanisms, using information from different sources. Because the diverse beam search algorithm can produce responses with entities that deviate from the predicted entities, an entity-revised diverse beam search is proposed to correct the entities entailed in the generated responses and make the generated responses more distinct. The experimental results on the China Conference on Knowledge Graph and Semantic Computing 2021(A/B tests) and the International Conference on Learning Representations 2021(online test) datasets show that the proposed method outperforms several state-of-the-art methods, which demonstrates its practicability and effectiveness.

关键词： medical entity prediction ent-mac post pre-training strategy entity-aware fusion medical dialogue generation encoding fusion mechanism entity-revised diverse beam search

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

Gear walk instability caused by brake-disc friction characteristics

引用

Chinese Journal of Aeronautics 2024年第2期37卷 343-359页

作者： Xiaoqiong DU bin li Wen CAI linyin LUO School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China Department of Mechanical Engineering University of MichiganAnn Arbor 48109USA AVIC General Huanan Aircraft Industry Co.Ltd. Zhuhai 519040China

A multi-body dynamic rigid-flexible coupling model of landing gear is established to study the gear walk instability caused by the friction characteristics of the brake *** validating the model with the experimental results,the influence of the landing gear structure and braking system parameters on gear walk is further *** the above factors,the slope of the graph for the friction coefficient of the brake disc and the relative velocity of brake stators and rotors is the most influential factor on gear walk *** trajectory analysis verifies that gear walk occurs when the coupling of multiple factors causes the system to exhibit an equivalent negative damping *** consider a more realistic braking case,a back propagation neural network method is employed to describe the nonlinear behavior of the friction coefficient of the brake *** the realistic nonlinear model of the friction coefficient,the maximum error in predicting the braking torque is less than 10%and the effect of the brake disc temperature on gear walk is *** results reveal that a more negative friction slope may contribute to a more severe unstable gear walk,and reducing the braking pressure is an effective approach to avoid gear walk,which provides help for future braking system design.

关键词： Gear walk Friction characteristics of brake disc Brake-induced vibration Negative damping Rigid-flexible coupling Negative slope of braking torque

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

Zeolite-encaged gold catalysts for the oxidative condensation of furfural

引用

Frontiers of Chemical Science and Engineering 2024年第8期18卷 67-77页

作者： Weijie li Mingyang Gao bin Qin Xin Deng Landong li School of Materials Science and Engineering Nankai UniversityTianjin 300350China College of Chemistry Nankai UniversityTianjin 300071China Haihe Laboratory of Sustainable Chemical Transformations Tianjin 300192China

The oxidative condensation between renewable furfural and fatty alcohols is a crucial avenue for producing high-quality liquid fuels and valuable furan *** selectivity control in this reaction process remains a significant ***,we report the strategy of confining well dispersed gold species within ZSM-5 structure to construct highly active Au@ZSM-5 zeolite catalysts for the oxidative condensation of *** results and spectroscopy analyses demonstrate the efficient encapsulation of isolated and cationic Au clusters in zeolite ***@ZSM-5(K)catalyst shows remarkable performance with 69.7%furfural conversion and 90.2%furan-2-acrolein selectivity as well as good recycle *** is revealed that the microstructure of ZSM-5 zeolite can significantly promote oxidative condensation activity through confinement *** work presents an explicit example of constructing zeolite encaged noble metal catalysts toward targeted chemical transformations.

关键词： zeolite encapsulation gold oxidative condensation furfural

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

Advanced Design of Soft Robots with Artificial Intelligence

引用

Nano-Micro Letters 2024年第10期16卷 474-521页

作者： Ying Cao bingang Xu bin li Hong Fu Nanotechnology Center School of Fashion and TextilesThe Hong Kong Polytechnic UniversityHong Kong 999077People's Republic of China Department of Mathematics and Information Technology The Education University of Hong KongHong Kong 999077People's Republic of China Bioinspired Engineering and Biomechanics Center Xi'an Jiaotong UniversityXi'an 710049People's Republic of China

In recent years,breakthrough has been made in the field of artificial intelligence(AI),which has also revolutionized the industry of *** robots featured with high-level safety,less weight,lower power consumption have always been one of the research ***,multifunctional sensors for perception of soft robotics have been rapidly developed,while more algorithms and models of machine learning with high accuracy have been optimized and *** of soft robots with AI have also been advanced ranging from multimodal sensing,human-machine interaction to effective actuation in robotic ***-less,comprehensive reviews concerning the new developments and strategies for the ingenious design of the soft robotic systems equipped with AI are ***,the new development is systematically reviewed in the field of soft robots with ***,background and mechanisms of soft robotic systems are briefed,after which development focused on how to endow the soft robots with AI,including the aspects of feeling,thought and reaction,is ***,applications of soft robots with AI are systematically summarized and discussed together with advanced strategies proposed for performance *** thoughts for future intelligent soft robotics are pointed ***,some perspectives are put forward.

关键词： Soft robotic systems Artificial intelligence Design tactics Review and perspective

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

Switching Behavior of Cascode GaN Under Influence of Gate Driver

引用

CSEE Journal of Power and Energy Systems 2024年第4期10卷 1816-1833页

作者： bin Luo Guangzhao Luo Sihai li School of Automation Northwestern Polytechnical UniversityXi’an 710072China

With high-frequency,low power dissipation and high-efficiency characteristics,Gallium nitride(GaN)power devices are of significant benefit in designing high-speed motor drives,as they improve performance and reduce ***,due to the cascode structure,coupling with the parasitics in gate driver and power circuits,power converters based on cascode GaN are prone to overshoot and oscillate on switching waveforms,which may lead to serious EMC problems,or even device *** complicated structure of cascode GaN device makes the gate driver design comparatively *** analytical model of the switching process considering gate driver parameters is proposed in this *** influence of gate driver parameters on switching behavior is investigated from the perspective of switching speed,waveform overshoot,and power ***-offs among overshoot,switching speed,and power loss are discussed;guidelines to design gate driver parameters are given.

关键词： Gallium nitride(GaN) gate driver oscillation and overshoot switching characteristics

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

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：