检索结果-南通市图书馆

Wind-Vortex-Induced Vibrations of a Deepwater Jacket Pipe and Vibration Suppression Using a Nonlinear Energy Sink

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3期23卷 633-642页

作者： LIU Liqin YU Yongjun CHEN yiqun State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China China Classification Society Haikou 570102China

The purpose of this study is to investigate the suppression effect of a nonlinear energy sink(NES)on the wind-vortex-induced pipe vibration and explore the influence of damping,stiffness,and NES installation position on the suppression effect.In this work,the wind-vortex-induced vibration of an elastic pipe of a deepwater jacket was studied,and vibrations were suppressed by using an NES.A van der Pol wake oscillator was used to simulate vortex-induced force,and the dynamic equation of the pipe considering the NES was established.The Galerkin method was applied to discretize the motion equation,and the vortex-induced vibration(VIV)of the pipe at reduced wind speeds was numerically analyzed.The novelty of this research is that particle swarm optimization was used to optimize the parameters of the NES to improve vibration suppression.The influence of the installation position,nonlinear stiffness,and damping parameters of the NES on vibration suppression was analyzed.Results showed that the optimized parameter combinations of the NES can effectively reduce wind-vortex-induced pipe vibration.The installation position of the NES had a significant effect on vibration suppression,and the midpoint of the pipe was the optimal NES installation position.An increase in stiffness or a 10% decrease in damping may cause vibration suppression failure.The results of this study provide some guidance for VIV suppression in deepwater jacket pipes.

关键词： deepwater jacket wind-vortex-induced vibration NES PSO vibration suppression effect analysis

Decoding the Cellular Trafficking of Prion-like Proteins in Neurodegenerative Diseases

维普期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Neuroscience Bulletin 2024年第2期40卷 241-254页

作者： Chenjun Hu yiqun Yan Yanhong Jin Jun Yang Yongmei Xi Zhen Zhong Department of Neurology of the Second Afliated Hospital and Department of Human Anatomy Histology and EmbryologyZhejiang University School of MedicineHangzhou 310058China Department of Physiology and Department of Cardiology of the Second Afliated Hospital Zhejiang University School of MedicineHangzhou 310058China Division of Human Reproduction and Developmental Genetics Women’s Hospital and Institute of GeneticsZhejiang University School of MedicineHangzhou 310006China

The accumulation and spread of prion-like proteins is a key feature of neurodegenerative diseases(NDs)such as Alzheimer’s disease,Parkinson's disease,or Amyotrophic Lateral Sclerosis.In a process known as‘seeding’,prion-like proteins such as amyloid beta,microtubule-associated protein tau,α-synuclein,silence superoxide dismutase 1,or transactive response DNA-binding protein 43 kDa,propagate their misfolded conformations by transforming their respective soluble monomers into fibrils.Cellular and molecular evidence of prion-like propagation in NDs,the clinical relevance of their‘seeding’capacities,and their levels of contribution towards disease progression have been intensively studied over recent years.This review unpacks the cyclic prion-like propagation in cells including factors of aggregate internalization,endo-lysosomal leaking,aggregate degradation,and secretion.Debates on the importance of the role of prion-like protein aggregates in NDs,whether causal or consequent,are also discussed.Applications lead to a greater understanding of ND pathogenesis and increased potential for therapeutic strategies.

关键词： Neurodegenerative diseases Prion-like propagation Seeding Endocytosis Endolyosomal leaking Degradation

Planning method of droplet fusion scheduling based on mixedinteger programming

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第1期67卷 157-171页

作者： XIONG JiaCong CHEN JianKui WANG YiXin YIN ZhouPing LI yiqun State Key Laboratory of Intelligent Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The emergence of new display devices,such as organic light-emitting diodes,has brought about numerous advantages,including high material utilization,low cost,and high adaptability.These devices are manufactured using inkjet printing and possess the potential to become a key technology for display transformations.However,a challenge in achieving this is the display effect that reveals uneven brightness and darkness,which can be avoided by controlling the volume of ink solution in a pixel to within 5%.Currently,the volume difference among the nozzles of commercial printheads does not meet the requirements for volume uniformity,thus challenging the printing process.Therefore,designing a suitable printing method that allows for the fusion of different volumes of ink droplets,ultimately reducing the error of the post fusion process,is necessary.In this study,we propose a print display droplet fusion scheduling method comprising two main steps.First,we use a dichotomous trust domain algorithm to obtain a feasible range of printhead docking point spacings for different nozzle and pixel panel resolutions.Second,we model the printing process as a droplet fusion scheduling model based on mixed integer programming,with the optimization objective of achieving intra pixel volume uniformity via ensuring the volume uniformity of ink droplets within all pixels.We verified this method through numerical simulations and printing experiments using 394 pixels per inch(ppi)pixel panels and successfully reduced the volume uniformity error among pixels to within 5%.

关键词： printing display droplet fusion mixed-integer programming dichotomous trust domain

维普期刊数据库

Investigation of FRP and SFRC Technologies for Efficient Tunnel Reinforcement Using the Cohesive Zone Model

在线全文

学校读者我要写书评

暂无评论

Structural Durability & Health Monitoring 2024年第2期18卷 161-179页

作者： Gang Niu Zhaoyang Jin Wei Zhang yiqun Huang China Communications Construction Investment Development Co. Ltd.Fuzhou350000China Rail Transit Branch of China Communications Construction Co. Ltd.Beijing101317China School of Civil Engineering Fujian University of TechnologyFuzhou350118China

Amid urbanization and the continuous expansion of transportation networks,the necessity for tunnel construction and maintenance has become paramount.Addressing this need requires the investigation of efficient,economical,and robust tunnel reinforcement techniques.This paper explores fiber reinforced polymer(FRP)and steel fiber reinforced concrete(SFRC)technologies,which have emerged as viable solutions for enhancing tunnel structures.FRP is celebrated for its lightweight and high-strength attributes,effectively augmenting load-bearing capacity and seismic resistance,while SFRC’s notable crack resistance and longevity potentially enhance the performance of tunnel segments.Nonetheless,current research predominantly focuses on experimental analysis,lacking comprehensive theoretical models.To bridge this gap,the cohesive zone model(CZM),which utilizes cohesive elements to characterize the potential fracture surfaces of concrete/SFRC,the rebar-concrete interface,and the FRP-concrete interface,was employed.A modeling approach was subsequently proposed to construct a tunnel segment model reinforced with either SFRC or FRP.Moreover,the corresponding mixed-mode constitutive models,considering interfacial friction,were integrated into the proposed model.Experimental validation and numerical simulations corroborated the accuracy of the proposed model.Additionally,this study examined the reinforcement design of tunnel segments.Through a numerical evaluation,the effectiveness of innovative reinforcement schemes,such as substituting concrete with SFRC and externally bonding FRP sheets,was assessed utilizing a case study from the Fuzhou Metro Shield Tunnel Construction Project.

关键词： Tunnel segment FRP SFRC cohesive zone model constitutive model fracture process

Absorption properties and mechanism of lightweight and broadband electromagnetic wave-absorbing porous carbon by the swelling treatment

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1701-1712页

作者： Jianghao Wen Di Lan yiqun Wang Lianggui Ren Ailing Feng Zirui Jia Guanglei Wu College of Materials and Chemistry&Chemical Engineering Chengdu University of TechnologyChengdu 610059China School of Materials Science and Engineering Hubei University of Automotive TechnologyShiyan 442002China Institute of Materials for Energy and Environment State Key Laboratory of Bio-fibers and Eco-textilesCollege of Materials Science and EngineeringQingdao UniversityQingdao 266071China Institute of Physics&Optoelectronics Technology Baoji University of Arts and SciencesBaoji 721016China

Bioderived carbon materials have garnered considerable interest in the fields of microwave absorption and shielding due to their reproducibility and environmental friendliness.In this study,KOH was evenly distributed on biomass Tremella using the swelling induction method,leading to the preparation of a three-dimensional network-structured hierarchical porous carbon(HPC)through carbonization.The achieved microwave absorption intensity is robust at-47.34 dB with a thin thickness of 2.1 mm.Notably,the widest effective absorption bandwidth,reaching 7.0 GHz(11–18 GHz),is attained at a matching thickness of 2.2 mm.The exceptional broadband and reflection loss performance are attributed to the 3D porous networks,interface effects,carbon network defects,and dipole relaxation.HPC has outstanding absorption characteristics due to its excellent impedance matching and high attenuation constant.The uniform pore structures considerably optimize the impedance-matching performance of the material,while the abundance of interfaces and defects enhances the dielectric loss,thereby improving the attenuation constant.Furthermore,the impact of carbonization temperature and swelling rate on microwave absorption performance was systematically investigated.This research presents a strategy for preparing absorbing materials using biomass-derived HPC,showcasing considerable potential in the field of electromagnetic wave absorption.

关键词： biomass hierarchical porous carbon dielectric loss electromagnetic wave absorption

维普期刊数据库

Bioinspired Tactile Sensation Based on Synergistic Microcrack-Bristle Structure Design toward High Mechanical Sensitivity and Direction-Resolving Capability

在线全文

学校读者我要写书评

暂无评论

Research 2024年第1期2023卷 611-624页

作者： yiqun Zhang Qi Liu Wenjuan Ren Yangyang Song Hua Luo Yangyang Han Liang He Xiaodong Wu Zhuqing Wang School of Mechanical Engineering Sichuan UniversityChengdu 610065China Med+X Center for Manufacturing West China HospitalSichuan UniversityChengdu 610041China State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan UniversityChengdu 610065China

Natural tactile sensation is complex,which involves not only contact force intensity detection but also the perception of the force direction,the surface texture,and other mechanical parameters.Nevertheless,the vast majority of the developed tactile sensors can only detect the normal force,but usually cannot resolve shear force or even distinguish the directions of the force.Here,we present a new paradigm of bioinspired tactile sensors for resolving both the intensity and the directions of mechanical stimulations via synergistic microcrack-bristle structure design and cross-shaped configuration engineering.The microcrack sensing structure gives high mechanical sensitivity to the tactile sensors,and the synergistic bristle structure further amplifies the sensitivity of the sensors.The cross-shaped configuration engineering of the synergistic microcrack-bristle structure further endows the tactile sensors with good capability to detect and distinguish the directions of the applied mechanical forces.The as-fabricated tactile sensors exhibit a high sensitivity(25.76 N^(−1)),low detection limit(5.4 mN),desirable stability(over 2,500 cycles),and good capability to resolve both mechanical intensity and directional features.As promising application scenarios,surface texture recognition and biomimetic path explorations are successfully demonstrated with these tactile sensors.This newly proposed tactile sensation strategy and technology have great potential applications in ingenious tactile sensation and construction of various robotic and bionic prostheses with high operational dexterity.

关键词： crack sensation directions

Do investors care about auditor assignments?Evidence from last-minute changes to signing auditors

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

China Journal of Accounting Research 2024年第1期17卷 132-156页

作者： Yangyang Wang yiqun Xie Huanmin Yan Rui Zhang School of Accounting Jiangxi University of Finance and EconomicsNanchangChina School of Economics&Management Nanchang UniversityNanchangChina

Against the background of China’s strengthening of finance and accounting supervision,this study examines the practice among listed companies of changing signing auditors at the last minute and explores whether Chinese investors can capture this information in a timely manner.We find that China’s capital market responds significantly negatively to these last-minute changes,implying that investors perceive a potential negative impact of this behavior.Crosssectional analyses suggest that the characteristics of the change event,recent corporate events,and accounting firm capability significantly affect the stock price response.Furthermore,in terms of the individual characteristics of signing auditors,external investors appear to comprehensively consider busyness level,industry experience,and the timing of the change to determine the causes and effects of the auditor change and make different market reactions accordingly.In addition,consistent with investor perceptions,we find that last-minute changes significantly impair the quality of financial statements,indicating that external investors’judgments based on information about changes in signing auditors are rational and effective.

关键词： Annual Financial Report Auditing Changing Signing Auditors at the Last Minute Market Response Financial Statement Quality

基于鲁棒稀疏宽度学习系统的短期风电功率预测

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

太阳能学报 2024年第5期45卷 32-43页

作者：康逸群刘厦雷兢中国电力科学研究院有限公司北京100192 华北电力大学能源动力与机械工程学院北京102206

为改善预测质量,提出一种基于鲁棒稀疏宽度学习系统(RSBLS)的预测方法。基于正则法将模型训练转化为一个difference-of-convex functions优化问题,利用L1范数作为数据忠诚项以提高估计的鲁棒性,将L1-2范数集成到目标函数中确保输出权的... 详细信息

为改善预测质量,提出一种基于鲁棒稀疏宽度学习系统(RSBLS)的预测方法。基于正则法将模型训练转化为一个difference-of-convex functions优化问题,利用L1范数作为数据忠诚项以提高估计的鲁棒性,将L1-2范数集成到目标函数中确保输出权的稀疏性以提升模型性能,并提出一种融合half-quadratic splitting算法优势的数值方法有效求解该训练模型。基于绝对误差、相对误差、平均绝对误差、均方根误差、平均绝对百分误差、算法稳定性、预测误差改进百分比、灰色关联分析和DM检验等准则进行实验分析,结果表明新算法的预测质量优于流行的预测算法,并具有较好的鲁棒性,为风功率预测提出一种可行的新方法。

关键词：风功率预测宽度学习系统正则化稀疏性优化

维普期刊数据库博看期刊

On-chip spiking neural networks based on add-drop ring microresonators and electrically reconfigurable phase-change material photonic switches

在线全文

学校读者我要写书评

暂无评论

Photonics Research 2024年第4期12卷 755-766页

作者： QIANG ZHANG NING JIANG yiqun ZHANG ANRAN LI HUANHUAN XIONG GANG HU YONGSHENG CAO KUN QIU School of Information and Communication Engineering University of Electronic Science and Technology of ChinaChengdu 611731China

We propose and numerically demonstrate a photonic computing primitive designed for integrated spiking neural networks (SNNs) based on add-drop ring microresonators (ADRMRs) and electrically reconfigurable phasechange material (PCM) photonic switches. In this neuromorphic system, the passive silicon-based ADRMR,equipped with a power-tunable auxiliary light, effectively demonstrates nonlinearity-induced dual neural dynamics encompassing spiking response and synaptic plasticity that can generate single-wavelength optical neural spikes with synaptic weight. By cascading these ADRMRs with different resonant wavelengths, weighted multiple-wavelength spikes can be feasibly output from the ADRMR-based hardware arrays when external wavelengthaddressable optical pulses are injected;subsequently, the cumulative power of these weighted output spikes is utilized to ascertain the activation status of the reconfigurable PCM photonic switches. Moreover, the reconfigurable mechanism driving the interconversion of the PCMs between the resonant-bonded crystalline states and the covalent-bonded amorphous states is achieved through precise thermal modulation. Drawing from the thermal properties, an innovative thermodynamic leaky integrate-and-firing (TLIF) neuron system is proposed. With the TLIF neuron system as the fundamental unit, a fully connected SNN is constructed to complete a classic deep learning task:the recognition of handwritten digit patterns. The simulation results reveal that the exemplary SNN can effectively recognize 10 numbers directly in the optical domain by employing the surrogate gradient algorithm. The theoretical verification of our architecture paves a whole new path for integrated photonic SNNs, with the potential to advance the field of neuromorphic photonic systems and enable more efficient spiking information processing.

关键词： neural networks precise

维普期刊数据库