检索结果-内蒙古大学图书馆

SSRN 2023年

作者： Li, Xiaoqiang Xu, Qiyong Liu, Yangfan Zhang, Jiantao Liu, Dexue Le, Qichi Wang, Jinhui Zhu, Yunpeng Hu, Wenxin State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals Lanzhou University of Technology Lanzhou730050 China Key Laboratory of Electromagnetic Processing of Materials Ministry of Education Northeastern University Shenyang110819 China Qinghai Provincial Key Laboratory of New Light Alloys Qinghai Provincial Engineering Research Center of High Performance Light Metal Alloys and Forming Qinghai University Xining810016 China State Key Laboratory of Baiyunobo Rare Earth Resource Research and Comprehensive Utilization Baotou Research Institute of Rare Earths Baotou014030 China

Abstract: In this study, Mg-1.5Al-xwt%La-Mn (ALaM-x) (x = 0.5, 1, and 2) alloys were prepared by melting and casting followed by hot extrusion at 300 °C. The microstructure evolution and mechanical behavior of the alloys were studied. By observing the microstructure, it was found that the precipitated phases occurred the evolution of Al11La3 → Al2.12La0.88/Al2La → Mg12La with the decrease of Al/La, and the precipitated Al11La3 coarsened gradually with the increase of La amount. After extrusion, the fine rod-like Al11La3 was broken and refined, but the coarse Al11La3 was not completely broken, and aggregated and unevenly distributed in Mg matrix. Compared with the extruded pure Mg, the extruded ALaM-0.5 alloy presented finer microstructure with an average grain size of 1.83 μm and a refinement rate of 90%. The mechanical properties of the alloy exhibited a considerable improvement of TYS~262.5±3.0 MPa, UTS~275.0±2.4 MPa, an increase rate of 124.7% and 52.1%, respectively. Based on theoretical analysis, the high strength of the alloy was mainly attributed to refinement strengthening, dislocation strengthening, precipitation strengthening and texture strengthening, among them, refinement strengthening up to 42%. Furthermore, the inverse Hall-Petch relationship between (d-1/2) and strain hardening exponents (n) was found, and the precipitated phase could delay the weakening trend of strain hardening capacity with decreasing grain size. © 2023, The Authors. All rights reserved.

关键词： Magnesium alloys

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Analysis and Control of Doubly Fed Induction Generator for Zero Voltage Ride Through

Analysis and Control of Doubly Fed Induction Generator for Z...

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International Conference on Electrical Machines and Systems

作者： Haiyan Tang Yuanzhu Chang Yongning Chi Bo Wang Yan Li Jiabing Hu State Key Laboratory of Operation and Control of Renewable Energy & Storage Systems China Electric Power Research Institute. Beijing 100192 China State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan 430074 China

ISBN: (纸本)9781467388634

The stator transient DC flux component emerges in the Double Fed Induction Generator (DFIG) following grid voltage dip, which results in an important influence on the controllability of rotor converter. In this paper, the research focuses on the responding time of the dynamic reactive current injection referring to DFIG with the crowbar protection under Zero Voltage Ride-Through (ZVRT). Firstly, theoretical analysis about the shortest quitting time of crowbar is carried out. Then, combined with crowbar protection and demagnetization control, ZVRT of DFIG is achieved as well as the fast injection of dynamic reactive current. Finally, the simulation results are presented to verify the theoretical analysis and the proposed control strategy. It is helpful to enhance fault ride through capability of DFIG.

关键词： Crowbar DFIG Dynamic reactive current injection ZVRT

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Efficiency-boosted semiconductor optical amplifiers via mode-division-multiplexing

arXiv

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arXiv 2023年

作者： Wang, Yi Wei, Yihui Dolores-Calzadilla, Victor Dai, Daoxin Williams, Kevin Smit, Meint Jiao, Yuqing Eindhoven University of Technology Eindhoven5600MB Netherlands Eindhoven University of Technology Eindhoven5600MB Netherlands State Key Laboratory for Modern Optical Instrumentation Center for Optical & Electromagnetic Research College of Optical Science and Engineering International Research Center for Advanced Photonics Zhejiang University Zijingang Campus Hangzhou310058 China Jiaxing Key Laboratory of Photonic Sensing & Intelligent Imaging Intelligent Optics & Photonics Research Center Jiaxing Research Institute Zhejiang University Jiaxing314000 China

Semiconductor optical amplifiers (SOA) are a fundamental building block for many photonic systems. However, their power inefficiency has been setting back operational cost reduction, and the resulting thermal losses constrain miniaturization, and the realization of more complex photonic functions such as large-scale switches and optical phased arrays. In this work, we demonstrate significant gain and efficiency enhancement using an extra degree of freedom of light - the mode space. This is done without changing the SOA's material design, and therefore high versatility and compatibility can be obtained. Light is multiplexed in different guided modes and is reinjected into the same gain section twice without introducing resonance, doubling the interaction length in a broadband manner. Up to 87% higher gain and 300% higher wall-plug efficiency are obtained in a double-pass SOA compared to a conventional single-pass SOA, at the same operating current, in the wavelength range of 1560-1580 nm. © 2023, CC BY.

关键词： Semiconductor optical amplifiers

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Multi-Scale Terahertz Image Reconstruction ⋆,⋆⋆

SSRN

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SSRN 2024年

作者： Su, Zhipeng Zhang, Yixiong Zhou, Jianyang Shi, Jianghong Qi, Feng Zhang, Xiao-Ping Ji, Chunlin School of Informatics Xiamen University National Demonstrative Software School Xiamen University China School of Electronic Science and Engineering National Model Microelectronics College Xiamen University China Shenyang Institute of Automation Chinese Academy of Sciences China Department of Electrical Computer & Biomedical Engineering Finance Department The Ted Rogers School of Management Toronto Metropolitan University Canada Kuang-Chi Institute of Advanced Technology State Key Laboratory of Meta-RF Electromagnetic Modulation Technology Shen Zhen China

This paper proposes a novel terahertz (THz) image recovery algorithm and a new THz image dataset is publicly available. Because of transmission noise, artificial errors and problems with diffraction phenomena are among the main problems that cause degradation of THz images. The point spread function (PSF) in real transmission is first obtained using a terahertz imaging system. Experiments can generate degraded images and clean image datasets for supervised training of neural networks via terahertz PSF. A Depthwise Dense Instantiation Normalization Block (DwDIN Block) has been proposed to recover the datasets. We constructed a powerful multi-stage network (DwDINet) at each scale by utilizing the DwDIN module. For input and output, the results of each stage of the network and the original images are taken as input into the next layer in order to enhance the background information. DwDINet achieves state-of-the-art (SOTA) results on the two main THz datasets. To verify the generality of the model, we performed experiments on various image recovery tasks. According to the experimental results, the proposed model is of great potential for the field of low-level image clarification. © 2024, The Authors. All rights reserved.

关键词： Optical transfer function

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Enhanced Simulation Study of ITER Core X-Ray Crystal Spectroscopy

Enhanced Simulation Study of ITER Core X-Ray Crystal Spectro...

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IEEE International Conference on Plasma Science (ICOPS)

作者： X. Jin Z. Cheng J. Zhang W. Yan Z. Chen N. Pablant L. Gao D. Lu M. O’Mullane R. Tieulent R. Barnsley State Key Laboratory of Advanced Electromagnetic Technology International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan China ITER Organization Route de Vinon-sur-Verdon CS 90 046 St. Paul Lez Durance Cedex France Princeton Plasma Physics Laboratory Princeton New Jersey United States of America HFIPS Chinese Academy of Science Institute of Plasma Physics Hefei China Department of Physics SUPA University of Strathclyde Glasgow United Kingdom

ISBN: (数字)9798350360912

ISBN: (纸本)9798350360929

The core X-Ray Crystal Spectroscopy (XRCS-Core) is a critical diagnostic tool dedicated to providing ion temperature and plasma rotation for the International Tokamak Experimental Reactor (ITER). To meet space constraints, a novel dual-reflection configuration involving multiple flat reflectors and spherical curved crystals has been proposed for ITER XRCS-Core [1].

关键词： Spectroscopy Crystals Ions Tokamak devices Plasmas Plasma temperature Inductors

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Ultralow-loss Fusion Splicing between Antiresonant Hollow-core Fibers

Ultralow-loss Fusion Splicing between Antiresonant Hollow-co...

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Asia Communications and Photonics Conference and Exhibition (ACP)

作者： Caoyuan Wang Jie Zhu Ruowei Yu Zhende Zhai Limin Xiao Advanced Fiber Devices and Systems Group Key Laboratory of Micro and Nano Photonic Structures (MoE) Key Laboratory for Information Science of Electromagnetic Waves (MoE) Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing School of Information Science and Technology Fudan University Shanghai China Shenzhen Sublime Photonics Co. Ltd. Shenzhen China Yiwu Research Institute of Fudan University Yiwu China Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics and Optoelectronic Engineering Shenzhen University Shenzhen China

An ultralow loss (0.08 dB) fusion splice between antiresonant hollow-core fibers (AR-HCFs) is demonstrated, where the transmission property of AR-HCF does not change within a wide working wavelength range.

关键词： Optical fiber losses Heating systems Splicing Asia Propagation losses Optical fiber communication Electron tubes

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Achieving increased resolution and reconstructed image quality with gradient variance modified super-resolution radial fluctuations

Research Square

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Research Square 2021年

作者： Gong, Xingyu Zhou, Li Yao, Longfang Zhang, Li Chen, Liwen Fei, Yiyan Mi, Lan Wang, Baoju Ma, Jiong Department of Optical Science and Engineering Shanghai Engineering Research Center of Ultra-precision Optical Manufacturing Key Laboratory of Micro and Nano Photonic Structures Ministry of Education Green Photoelectron Platform Fudan University 220 Handan Road Shanghai200433 China School of Life Sciences Fudan University 220 Handan Road Shanghai200433 China Centre for Optical and Electromagnetic Research Guangdong Provincial Key Laboratory of Optical Information Materials and Technology South China Academy of Advanced Optoelectronics South China Normal University Guangzhou510006 China Institute of Biomedical Engineering and Technology Academy for Engineer and Technology Fudan University 220 Handan Road Shanghai200433 China

Based on the calculation of the degree of gradient convergence, the super-resolution radial fluctuations (SRRF) algorithm can achieve higher resolution by combining temporal fluctuation analysis with localization microscopy methods. The algorithm is also capable of processing high-density fluorescence images. However, there are considerable artifacts due to high density, which lead to a loss of image resolution and low fidelity of images. This study demonstrates the use of fluorescence gradient fluctuations in super-resolution analysis and proposes gradient variance modified SRRF (gmSRRF) algorithm. The gmSRRF algorithm resolves finer structures and compensates for the loss of resolution caused by artifacts in SRRF images using relatively high-density stochastic optical reconstruction microscopy (STORM) data and conventional widefield, confocal, or structured illumination microscopy (SIM) imaging sequences. The effectiveness of this algorithm is proven by means of relevant simulations and experiments, which allow the reconstructed SRRF image to improve resolution and reduce artifacts and background noise. © 2021, CC BY.

关键词： Image resolution

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Hybrid thin-film lithium niobate micro-ring acousto-optic modulator for microwave-to-optical conversion

arXiv

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arXiv 2024年

作者： Wan, Lei Huang, Jiying Wen, Meixun Li, Huan Zhou, Wenfeng Yang, Zhiqiang Chen, Yuping Liu, Huilong Zeng, Siqing Liu, Dong Yang, Shuixian Dai, Daoxin Li, Zhaohui School of Physics Ningxia University Yinchuan750021 China Department of Electronic Engineering College of Information Science and Technology Jinan University Guangzhou510632 China State Key Laboratory of Extreme Photonics and Instrumentation Center for Optical & Electromagnetic Research College of Optical Science and Engineering International Research Center for Advanced Photonics Zhejiang University Zijingang Campus Hangzhou310058 China State Key Laboratory of Advanced Optical Communication Systems and Networks School of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China Guangdong Provincial Key Laboratory of Optoelectronic Information Processing Chips and Systems Sun Yat-sen University Guangzhou510275 China Zhuhai519000 China

Highly efficient acousto-optic modulation plays a vital role in the microwave-to-optical conversion. Herein, we demonstrate a hybrid thin-film lithium niobate (TFLN) racetrack micro-ring acousto-optic modulator (AOM) implemented with low-loss chalcogenide (ChG) waveguide. By engineering the electrode configuration of the interdigital transducer, the double-arm micro-ring acousto-optic modulation is experimentally confirmed in nonsuspended ChG loaded TFLN waveguide platform. Varying the position of blue-detuned bias point, the half-wave-voltage-length product VπL of the hybrid TFLN micro-ring AOM is as small as 9 mV·cm. Accordingly, the acousto-optic coupling strength is estimated to be 0.48 Hz s1/2 at acoustic frequency of 0.84 GHz. By analyzing the generation of phonon number from the piezoelectric transducer, the microwave-to-optical conversion efficiency is calculated to be 0.05%, approximately one order of magnitude larger than that of the state-of-the-art suspended counterpart. Efficient microwave-to-optical conversion thus provides new opportunities for low-power-consumption quantum information transduction using the TFLN-ChG hybrid piezo-optomechanical devices. © 2024, CC BY.

关键词： Thin films

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Automated Cardiac Vortex Ring Identification and Characterization Based on Recurrent All-Pairs Field Transforms and Lagrangian Averaged Vorticity Deviation

SSRN

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SSRN 2023年

作者： Yang, Ke Zeng, Shan Shi, Ruizheng Ghista, Dhanjoo N. Hu, Xin Lv, Site Zhang, Chris W.J. Zhang, Yi Wong, Kelvin K.L. School of Mathematics and Computer Science Wuhan Polytechnic University Wuhan430023 China Department of Cardiovascular Medicine Xiangya Hospital Central South University Changsha410008 China University 2020 Foundation San JoseCA95126 United States The State Key Laboratory of Advanced Electromagnetic Engineering and Technology School of Electrical and Electronic Engineering Huazhong University of Science and Technology Wuhan430074 China Department of Mechanical Engineering College of Engineering University of Saskatchewan SaskatoonSKS7N 5A9 Canada Machine Intelligence Laboratory College of Computer Science Sichuan University Chengdu610041 China School of Electrical and Electronic Engineering University of Adelaide AdelaideSA5005 Australia

Automated identification of cardiac vortices is a formidable task due to the complex nature of blood flow within the heart chambers. This study proposes a novel approach that algorithmically characterizes the identification criteria of these cardiac vortices based on Lagrangian Averaged Vorticity Deviation (LAVD). For this purpose, the Recurrent All-Pairs Field Transforms (RAFT) on the optical flow of Phase Contrast Magnetic Resonance Imaging (PC-MRI) is introduced to construct a continuous velocity field and reduce errors that arise from the integral process of LAVD. Additionally, Generalized Hough Transform (GHT) is applied for automated depiction of the structure of cardiac vortices. The effectiveness of this method is demonstrated and validated by the computation of the acquired cardiac flow data. The results of this comprehensive visual and analytical study show that the evolution of cardiac vortices can be effectively described and displayed, and the RAFT framework for optical flow can synthesize the in-between PC-MRIs with high accuracy. This allows cardiologists to acquire a deeper understanding of intracardiac hemodynamics and its impact on cardiac functional performance. © 2023, The Authors. All rights reserved.

关键词： Vortex flow

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Antiresonant Hollow-core Fiber with Ultralow Bending Loss

Antiresonant Hollow-core Fiber with Ultralow Bending Loss

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Asia Communications and Photonics Conference and Exhibition (ACP)

作者： Jie Zhu Caoyuan Wang Ruowei Yu Ye Wang Zhende Zhai Limin Xiao Shanghai Engineering Research Center of Ultra-Precision Optical Manufacturing School of Information Science and Technology Advanced Fiber Devices and Systems Group Key Laboratory of Micro and Nano Photonic Structures (MoE) Key Laboratory for Information Science of Electromagnetic Waves (MoE) Fudan University Shanghai China College of Physics and Optoelectronic Engineering Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province Shenzhen University Shenzhen China Shenzhen Sublime Photonics Co. Ltd. Shenzhen China Yiwu Research Institute of Fudan University Yiwu China

We have fabricated a 0.8-km long high performance antiresonant hollow-core fiber (AR-HCF) with a transmission attenuation of ~12 dB/km. And its bending loss behavior has been investigated theoretically and experimentally. The fabricated AR-HCF exhibits an outstanding anti-bending performance in wide wavelength range from 1300 nm to 1750 nm, and an ultralow bending loss @ 1612nm ≤10 dB/km at a bend radius of 1.6 cm is obtained.

关键词： Optical fiber losses Fabrication Optical interferometry Bending Quantum optics Attenuation Optical fiber communication

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