检索结果-南通市图书馆

Effect of Blood Circulation in Veins on Resonance Suppression of the Dragonfly Wing Constructed by Numerical Method

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Bionic engineering 2024年第2期21卷 877-891页

作者： Lijun Zhang Xu Zhang Kaifei Wang Zhenwei Gan Shibo Liu Xiao Liu Zhengjun Jing Xudong Cui Jiahui Lu Jing Liu College of Mechanical and electronic engineering China University of PetroleumQingdao266580China

To reveal the resonance suppression mechanism of the blood circulation in dragonfly wings,a numerical modeling method of dragonfly wings based on Voronoi diagrams is proposed,and the changes in mass,aerodynamic damping,and natural frequencies caused by blood circulation in veins are *** equivalent mass of blood,boundary conditions,and aerodynamic damping are calculated *** analysis and harmonic response analysis of wing models with different blood circulation paths are performed using the finite-element method(FEM).The vibration reduction ratioδis introduced to compare the damping efficiency of different mass ***,a natural frequency testing device is constructed to measure the natural frequencies of dragonfly *** results indicate that the shape,mass,and natural frequencies of the dragonfly wing model constructed by numerical method agree well with *** mass distribution on the wing can be altered by blood circulation,thereby adjusting the natural frequencies and achieving resonance *** highestδof 1.013 is observed in the C region when blood circulates solely in secondary veins,but it is still lower than theδof 1.017 when blood circulates in complete *** aerodynamic damping ratio(1.19–1.79%)should not be neglected in the vibration analysis of the beating wing.

关键词： Dragonfly wings Blood circulation Resonance suppression Voronoi diagram FEM

Broadband intelligent programmable metasurface with polarization-modulated self-adaptive electromagnetic functionality switching

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

Photonics Research 2024年第7期12卷 1395-1409页

作者： XIMING LI RUI XU XIAOFENG SUN YUAN ZHAO ZHAO YANG GUOHONG DU College of electronic engineering Chengdu University of Information TechnologyChengdu 610225China

Programmable metasurfaces have received a great deal of attention due to their ability to dynamically manipulate electromagnetic(EM) waves. Despite the rapid growth, most of the existing metasurfaces require manual control to switch among different functionalities, which poses severe limitations on practical applications. Here, we put forth an intelligent metasurface that has self-adaptive EM functionality switching in broadband without human participation. It is equipped with polarization discrimination antennas(PDAs) and feedback components to automatically adjust functionalities for the different incident polarization information.

关键词： equipped adjust polarization

Integrated bound-state-in-the-continuum photon-pair source

在线全文

学校读者我要写书评

暂无评论

Photonics Research 2024年第6期12卷 1322-1327页

作者： FAN YE YUE QIN CHENFEI CUI XIANKAI SUN HON KI TSANG Department of electronic engineering The Chinese University of Hong KongHong KongChina

Integrated photon-pair sources based on spontaneous parametric down conversion(SPDC)in novel high-χ^((2))materials are used in quantum photonic systems for quantum information processing,quantum metrology,and quantum ***,the need for extensive fabrication process development and optimization of dry-etching processes significantly impedes the rapid exploration of different material platforms for low-loss quantum photonic ***,bound states in the continuum(BICs)have emerged as a promising approach for realizing ultralow-loss integrated photonic circuits without requiring an etching *** realizations of BIC photonic circuits have,however,been limited primarily to the classical ***,we explore the BIC phenomena in the quantum regime and show that the etchless BIC platform is suitable for use in integrated entangled photon-pair sources based on the SPDC process in high-χ^((2))*** lithium niobate as an example,we demonstrate photon-pair generation at telecommunication wavelengths,attaining a maximum internal generation rate of 3.46 MHz,a coincidence-to-accidental ratio of 5773,and an experimental two‐photon interference visibility of 94%.Our results demonstrate that the BIC platform can be used for quantum photonic circuits,and this will enable the rapid exploration of different emergingχ^((2))materials for possible use in integrated quantum photonics in the future.

关键词： process quantum continuum

Differences between two methods to derive a nonlinear Schrödinger equation and their application scopes

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第2期33卷 421-429页

作者：陈羽西张恒段文山 College of Physics and electronic engineering Northwest Normal UniversityLanzhou 730070China

The present paper chooses a dusty plasma as an example to numerically and analytically study the differences between two different methods of obtaining nonlinear Schrödinger equation(NLSE).The first method is to derive a Korteweg–de Vries(KdV)-type equation and then derive the NLSE from the KdV-type equation,while the second one is to directly derive the NLSE from the original *** is found that the envelope waves from the two methods have different dispersion relations,different group *** results indicate that two envelope wave solutions from two different methods are completely *** results also show that the application scope of the envelope wave obtained from the second method is wider than that of the first one,though both methods are valuable in the range of their corresponding application *** is suggested that,for other systems,both methods to derive NLSE may be correct,but their nonlinear wave solutions are different and their application scopes are also different.

关键词： dusty plasmas nonlinear waves particle-in-cell simulation

A comparison of cross-correlation-based and phasecorrelation-based image registration algorithms for optical coherence tomographic angiography

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

Chinese Optics Letters 2024年第7期22卷 19-28页

作者： Yurui Pu Chaoliang Chen School of electronic Science&engineering Southeast UniversityNanjing 210096China

A large field of view is in high demand for disease diagnosis in clinical applications of optical coherence tomography(OCT)and OCT angiography(OCTA)*** to limits on the optical scanning range,the scanning speed,or the data processing speed,only a relatively small region could be acquired and processed for most of the current clinical OCT systems at one time and could generate a mosaic image of multiple adjacent small-region images with registration algorithms for disease *** this work,we investigated performing cross-correlation(instead of phase-correlation)in the workflow of the Fourier–Mellin transform(FMT)method(called dual-cross-correlation-based translation and rotation registration,DCCTRR)for calculating translation and orientation offsets and compared its performance to the FMT method used on OCTA images *** phantom and in vivo experiments were implemented for comparisons,and the results quantitatively demonstrate that DCCTRR can align OCTA images with a lower overlap rate,which could improve the scanning efficiency of large-scale imaging in clinical applications.

关键词： optical coherence tomography optical coherence tomographic angiography:image registration cross-correlation phase-correlation.

Day-ahead Voltage-stability-constrained Network Topology Optimization with Uncertainties

在线全文

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2024年第3期12卷 730-741页

作者： Dingli Guo Lei Wang Ticao Jiao Ke Wu Wenjing Yang the School of Electrical and electronic engineering Shandong University of TechnologyZibo 255000China

A day-ahead voltage-stability-constrained network topology optimization(DVNTO)problem is proposed to find the day-ahead topology schemes with the minimum number of operations(including line switching and bus-bar splitting)while ensuring the sufficient hourly voltage stability margin and the engineering operation requirement of power *** AC continuation power flow and the uncertainty from both renewable energy sources and loads are incorporated into the *** proposed DVNTO problem is a stochastic,largescale,nonlinear integer programming *** solve it tractably,a tailored three-stage solution methodology,including a scenario generation and reduction stage,a dynamic period partition stage,and a topology identification stage,is ***,to address the challenges posed by uncertainties,a novel problem-specified scenario reduction process is proposed to obtain the representative ***,to obtain the minimum number of necessary operations to alter the network topologies for the next 24-hour horizon,a dynamic period partition strategy is presented to partition the hours into several periods according to the hourly voltage information based on the voltage stability ***,a topology identification stage is performed to identify the final network topology *** effectiveness and robustness of the proposed three-stage solution methodology under different loading conditions and the effectiveness of the proposed partition strategy are evaluated on the IEEE 118-bus and 3120-bus power systems.

关键词： Network topology optimization static voltage stability line switching bus-bar splitting renewable energy source

A Joint Activity and Data Detection Scheme for Asynchronous Grant-Free Rateless Multiple Access

在线全文

学校读者我要写书评

暂无评论

China Communications 2024年第1期21卷 34-52页

作者： Wei Zhang Xiaofeng Zhong Shidong Zhou Department of electronic engineering Tsinghua UniversityBeijing 100084China

This paper considers the frameasynchronous grant-free rateless multiple access(FAGF-RMA)scenario,where users can initiate access at any symbol time,using shared channel resources to transmit data to the base *** coding is introduced to enhance the reliability of the *** literature has shown that FA-GFRMA can achieve lower access delay than framesynchronous grant-free rateless multiple access(FSGF-RMA),with extreme reliability enabled by rateless *** support FA-GF-RMA in more practical scenarios,a joint activity and data detection(JADD)scheme is *** the feature of sporadic traffic,approximate message passing(AMP)is exploited for transmission signal matrix ***,to determine the packet start points,a maximum posterior probability(MAP)estimation problem is solved based on the recovered transmitted signals,leveraging the intrinsic power pattern in the *** iterative power-pattern-aided AMP algorithm is devised to enhance the estimation performance of *** results verify that the proposed solution achieves a delay performance that is comparable to the performance limit of FA-GF-RMA.

关键词： asynchronous grant-free JADD rateless codes

Low Loss and Low EMI Noise Trench IGBT with Shallow Emitter Trench Controlled P-Type Dummy Region

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of electronics 2024年第2期33卷 326-335页

作者： Jinping ZHANG Xiaofeng LI Rongrong ZHU Kang WANG Bo ZHANG State Key Laboratory of electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China (UESTC) Institute of electronic and Information engineering of UESTC in Guangdong

A novel trench insulated gate bipolar transistor（TIGBT） with a shallow emitter trench controlled P-type dummy region（STCP-TIGBT） is *** with the conventional TIGBT with floating P-type dummy region（CFP-TIGBT） and TIGBT with floating P-type dummy region and normally on hole path（HFPTIGBT）,the proposed STCP structure not only speeds up the extraction of excessive holes in the turn-off process but also reduces the Miller plateau charge(Qgc).Therefore,both the power loss and electromagnetic interference（EMI） noise are significantly *** results show that the Qgcof the proposed device is only 501 nC/cm2,which is reduced by 58.5% and 26.4% when compared to the CFP-TIGBT and HFP-TIGBT,*** same on-state voltage drop(Vceon) of 1.02 V,the turn-off loss(Eoff) of the proposed device is 13.49 mJ/cm2,which is 64.6%and 67.6% less than those of the CFP-TIGBT and HFP-TIGBT,***,the reverse recovery dVak/dt of the freewheeling diode at same turn-on loss(Eon) of 31.8 mJ/cm2for the proposed STCP-TIGBT is only 2.15 kV/μs,which is reduced by 91.3% and 57.2% when compared to 24.69 kV/μs and 5.02 kV/μs for the CFP-TIGBT and HFPTIGBT,*** reduced dV/dt significantly suppresses the electromagnetic interference noise generated by the proposed device.

关键词： Insulated gate bipolar transistors Electrodes Annealing Simulation Electromagnetic interference Noise Voltage

Electromagnetic scattering and imaging simulation of extremely large-scale sea-ship scene based on GPU parallel technology

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of electronic Science and Technology 2024年第2期22卷 16-23页

作者： Cheng-Wei Zhang Zhi-Qin Zhao Wei Yang Li-Lai Zhou Hai-Yu Zhu Southwest China Institute of electronic Technology Chengdu610036China School of electronic Science and engineering University of Electronic Science and Technology of ChinaChengdu611731China Tencent Company Shenzhen518054China

Aiming to solve the bottleneck problem of electromagnetic scattering simulation in the scenes of extremely large-scale seas and ships,a high-frequency method by using graphics processing unit(GPU)parallel acceleration technique is *** the implementation of different electromagnetic methods of physical optics(PO),shooting and bouncing ray(SBR),and physical theory of diffraction(PTD),a parallel computing scheme based on the CPU-GPU parallel computing scheme is realized to balance computing ***,a multi-GPU framework is further proposed to solve the computational difficulty caused by the massive number of ray tubes in the ray tracing *** using the established simulation platform,signals of ships at different seas are simulated and their images are achieved as *** is shown that the higher sea states degrade the averaged peak signal-to-noise ratio(PSNR)of radar image.

关键词： Multi graphics processing unit Radar imaging Sea-ship Shooting and bouncing rays