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Supercapacitors with alternating current line-filtering performance

BMC Materials 2020年第1期2卷 1-20页

作者： Doudou Zhao Xiaodong Zhuang Kaiyue Jiang Sheng Han Jiantong Li Xiang Zhu Changchun Ke Emmanuel Kymakis The Meso-Entropy Matter Lab School of Chemistry and Chemical Engineering Shanghai Key Laboratory of Electrical Insulation and Thermal Aging State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong University Dongchuan Road 800 Shanghai 200240 China School of Chemical and Environmental Engineering Shanghai Institute of Technology Haiquan Road 100 Shanghai 201418 China Jiangsu Key Laboratory of Environmentally Friendly Polymeric Materials School of Materials Science and Engineering Changzhou University Changzhou 213164 China School of Information and Communication Technology KTH Royal Institute of Technology Electrum 229 16440 Kista Sweden State Key Laboratory for Oxo Synthesis and Selective Oxidation Suzhou Research Institute of Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Suzhou 215000 China School of Mechanical Engineering Shanghai Jiao Tong University Shanghai 200240 China Department of Electrical and Computer Engineering Hellenic Mediterranean University Estavromenos 71410 Heraklion Crete Greece

Alternating current (AC) line filters have been widely used to smooth the leftover AC ripples on direct current voltage. Currently available commercial aluminum electrolytic capacitors (AECs) are primarily used for this application. However, the bulky volume and low capacitance of AECs have become incompatible with the rapidly developed intelligent electronic devices and industry dynamics. Supercapacitors with high specific capacitance and AC line-filtering performance could become the next-generation candidates to replace AECs for smoothing leftover AC ripples. Thus, most conventional supercapacitors behave like a resistor and not a capacitor at 120 Hz mainly because complex pore structures of electrode materials prevent the diffusion of electrolyte ions. Various electrode materials have been reported to reveal supercapacitors with AC line-filtering performance; however, the balance of high specific capacitance and an excellent filtering efficiency is a prodigious challenge. This review summarizes recently reported supercapacitors based on different types of electrode materials with AC filtering performance and attempts to develop the relationship between different influencing factors and features of functional materials.

关键词： Supercapacitor Micro-supercapacitor Alternating current line filtering Phase angle Electrode

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Reconfigurable intelligent surfaces-assisted multiuser MIMO uplink transmission with partial CSI

arXiv

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arXiv 2020年

作者： You, Li Xiong, Jiayuan Huang, Yufei Ng, Derrick Wing Kwan Pan, Cunhua Wang, Wenjin Gao, Xiqi National Mobile Communications Research Laboratory Southeast University Nanjing210096 China Purple Mountain Laboratories Nanjing211100 China School of Electrical Engineering and Telecommunications University of New South Wales SydneyNSW2052 Australia School of Electronic Engineering and Computer Science Queen Mary University of London LondonE1 4NS United Kingdom

This paper considers the application of reconfigurable intelligent surfaces (RISs) (a.k.a. intelligent reflecting surfaces (IRSs)) to assist multiuser multiple-input multiple-output (MIMO) uplink transmission from several multi-antenna user terminals (UTs) to a multi-antenna base station (BS). For reducing the signaling overhead, only partial channel state information (CSI), including the instantaneous CSI between the RIS and the BS as well as the slowly varying statistical CSI between the UTs and the RIS, is exploited in our investigation. In particular, an optimization framework is proposed for jointly designing the transmit covariance matrices of the UTs and the RIS phase shift matrix to maximize the system global energy efficiency (GEE) with partial CSI. We first obtain closed-form solutions for the eigenvectors of the optimal transmit covariance matrices of the UTs. Then, to facilitate the design of the transmit power allocation matrices and the RIS phase shifts, we derive an asymptotically deterministic equivalent of the objective function with the aid of random matrix theory. We further propose a suboptimal algorithm to tackle the GEE maximization problem with guaranteed convergence, capitalizing on the approaches of alternating optimization, fractional programming, and sequential optimization. Numerical results substantiate the effectiveness of the proposed approach as well as the considerable GEE gains provided by the RIS-assisted transmission scheme over the traditional baselines. Copyright © 2020, The Authors. All rights reserved.

关键词： Energy efficiency

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Physically-Constrained Transfer Learning through Shared Abundance Space for Hyperspectral Image Classification

arXiv

引用

arXiv 2020年

作者： Qu, Ying Baghbaderani, Razieh Kaviani Li, Wei Gao, Lianru Zhang, Yuxiang Qi, Hairong The Advanced Imaging and Collaborative Information Processing Group Department of Electrical Engineering and Computer Science University of Tennessee KnoxvilleTN37996 United States The School of Information and Electronics Beijing Institute of Technology Beijing100081 China The Key Laboratory of Digital Earth Science Aerospace Information Research Institute Chinese Academy of Sciences Beijing100094 China

Hyperspectral image (HSI) classification is one of the most active research topics and has achieved promising results boosted by the recent development of deep learning. However, most state-of-the-art approaches tend to perform poorly when the training and testing images are on different domains, e.g., source domain and target domain, respectively, due to the spectral variability caused by different acquisition conditions. Transfer learning-based methods address this problem by pre-training in the source domain and fine-tuning on the target domain. Nonetheless, a considerable amount of data on the target domain has to be labeled and non-negligible computational resources are required to retrain the whole network. In this paper, we propose a new transfer learning scheme to bridge the gap between the source and target domains by projecting the HSI data from the source and target domains into a shared abundance space based on their own physical characteristics. In this way, the domain discrepancy would be largely reduced such that the model trained on the source domain could be applied on the target domain without extra efforts for data labeling or network retraining. The proposed method is referred to as physically-constrained transfer learning through shared abundance space (PCTL-SAS). Extensive experimental results demonstrate the superiority of the proposed method as compared to the state-of-the-art. The success of this endeavor would largely facilitate the deployment of HSI classification for real-world sensing scenarios. Copyright © 2020, The Authors. All rights reserved.

关键词： Deep learning

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Nonlinear Virtual Inertia Control of WTGs for Enhancing Primary Frequency Response and Suppressing Drive-Train Torsional Oscillations

arXiv

引用

arXiv 2020年

作者： Liu, Bi Huang, Qi Zhao, Junbo Milano, Federico Zhang, Yingchen Sichuan Provincial Key Lab of Power System Wide-area Measurement and Control University of Electronic Science and Technology of China Chengdu Sichuan611731 China Department of Electrical and Computer Engineering Mississippi State University StarkvilleMS39762 United States School of Electrical and Electronic Engineering University College Dublin Dublin Ireland National Renewable Energy Laboratory GoldenCO80401 United States

Virtual inertia controllers (VICs) for wind turbine generators (WTGs) have been recently developed to compensate the reduction of inertia in power systems. However, VICs can induce low frequency torsional oscillations of the drive train of WTGs. This paper addresses this issue and develops a new nonlinear VIC based on objective holographic feedbacks theory. This approach allows transforming the original nonlinear control into a completely controllable system of Brunovsky’s type. Simulation results under various scenarios demonstrate that the proposed method outperforms existing VICs in terms of suppression of low frequency drive-train torsional oscillations, enhancement of system frequency nadir as well as fast and smooth recovery of WTG rotor speed to the original MPP point before the disturbance. The proposed method is also able to coordinate multiple WTGs. Copyright © 2020, The Authors. All rights reserved.

关键词： Frequency response

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Edge learning with unmanned ground vehicle: Joint path, energy and sample size planning

arXiv

引用

arXiv 2020年

作者： Liu, Dan Wang, Shuai Wen, Zhigang Cheng, Lei Wen, Miaowen Wu, Yik-Chung Beijing Key Laboratory of Work Safety Intelligent Monitoring Department of Electronic Engineering Beijing University of Posts and Telecommunications Beijing100876 China Department of Electrical and Electronic Engineering Southern University of Science and Technology Shenzhen518055 China Department of Computer Science and Technology Southern University of Science and Technology Shenzhen518055 China Shenzhen Research Institute of Big Data Shenzhen Guangdong China School of Electronic and Information Engineering South China University of Technology Guangzhou510641 China Department of Electrical and Electronic Engineering University of Hong Kong Hong Kong

Edge learning (EL), which uses edge computing as a platform to execute machine learning algorithms, is able to fully exploit the massive sensing data generated by Internet of Things (IoT). However, due to the limited transmit power at IoT devices, collecting the sensing data in EL systems is a challenging task. To address this challenge, this paper proposes to integrate unmanned ground vehicle (UGV) with EL. With such a scheme, the UGV could improve the communication quality by approaching various IoT devices. However, different devices may transmit different data for different machine learning jobs and a fundamental question is how to jointly plan the UGV path, the devices’ energy consumption, and the number of samples for different jobs? This paper further proposes a graph-based path planning model, a network energy consumption model and a sample size planning model that characterizes F-measure as a function of the minority class sample size. With these models, the joint path, energy and sample size planning (JPESP) problem is formulated as a large-scale mixed integer nonlinear programming (MINLP) problem, which is nontrivial to solve due to the high-dimensional discontinuous variables related to UGV movement. To this end, it is proved that each IoT device should be served only once along the path, thus the problem dimension is significantly reduced. Furthermore, to handle the discontinuous variables, a tabu search (TS) based algorithm is derived, which converges in expectation to the optimal solution to the JPESP problem. Simulation results under different task scenarios show that our optimization schemes outperform the fixed EL and the full path EL schemes. Copyright © 2020, The Authors. All rights reserved.

关键词： Intelligent vehicle highway systems

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Construction of Linear Tetramer-Type Acceptors for High-Efficiency and High-Stability Organic Solar Cells

引用

Angewandte Chemie 2025年第8期137卷

作者： Rui Zeng Jiawei Deng Xiaonan Xue Sengke Tan Lixuan Kan Yi Lin Wenkai Zhong Lei Zhu Fei Han Yuhao Zhou Xingyu Gao Ming Zhang Yongming Zhang Shengjie Xu Feng Liu School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative Molecules Shanghai Key Laboratory of Electrical Insulation and Thermal Aging Shanghai Jiao Tong University Shanghai 200240 China These authors contributed equally. Shanghai OPV Solar New Energy Technology Co. Ltd. Shanghai 201210 China Center for Advanced Low-dimension Materials State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and Engineering Donghua University Shanghai 201620 P. R. China Institute of Polymer Optoelectronic Materials and Devices State Key Laboratory of Luminescent Materials and Devices South China University of Technology Guangzhou 510640 China College of Computer Science Sichuan university Chendu 610207 China State Key Laboratory of Fluorinated Functional Membrane Materials and Dongyue Future Hydrogen Energy Materials Company Zibo City Shandong 256401 China Suzhou Laboratory Suzhou 215100 P. R. China

Thanks to the development of non-fullerene acceptor (NFA) materials, the photovoltaic conversion efficiency (PCE) of organic solar cells (OSCs) has exceeded 20 %, which has met the requirements for commercialisation. In the current stage, the main focus is to balance the performance and stability. It has been shown that all-polymer formulation can improve device stability, however, PCE is not in satifsfaction, and the batch-to-batch variation leads to quality control issues. In this work, we constructed monodispersed tetramer NFA materials named G-1 and G-2, to best integrate the merits of small molecule and polymer. Density functional theory (DFT) calculations and experimental results showed that different connecting units at the centre could significantly affect the molecular planarity and thin film morphology. The alkene-bonded tetramer G-1 had a more regioregular structure, which leads to better molecular planarity, and more ordered packing in thin film. More importantly, the oligomeration induced a favourable face-on orientation, achieved a lower binding energy and exhibited a higher photoluminescence yield. As a result, the exciton and charge carrier kinetics was optimized with reduced non-radiative energy loss. The OSC based on PM6 : G-1 achieved a PCE of 19.6 %, which is the highest PCE reported so far for oligomer-based binary OSC. In addition, the device stability was largely improved, showing a lifetime over 10000 hours in the inverted OSC device.

关键词： Organic solar cells Non-fullerene acceptor Tetramer Stability Energy loss

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A deep network for sinogram and CT image reconstruction

arXiv

引用

arXiv 2020年

作者： Wang, Wei Xia, Xiang-Gen He, Chuanjiang Ren, Zemin Lu, Jian Wang, Tianfu Lei, Baiying School of Biomedical Engineering Shenzhen University National-Regional Key Technology Engineering Laboratory for Medical Ultrasound Guangdong Key Laboratory for Biomedical Measurements and Ultrasound Imaging School of Biomedical Engineering Health Science Center Shenzhen University Shenzhen China College of Information Engineering Shenzhen University Shenzhen China College of Electrical and Computer Engineering University of Delaware NewarkDE19716 United States College of Mathematics and Statistics Chongqing University Chongqing China College of Mathematics and Physics Chongqing University of Science and Technology Chongqing China Shenzhen Key Laboratory of Advanced Machine Learning and Applications Shenzhen University Shenzhen China

A CT image can be well reconstructed when the sampling rate of the sinogram satisfies the Nyquist criteria and the sampled signal is noise-free. However, in practice, the sinogram is usually contaminated by noise, which degrades the quality of a reconstructed CT image. In this paper, we design a deep network for sinogram and CT image reconstruction. The network consists of two cascaded blocks that are linked by a filter backprojection (FBP) layer, where the former block is responsible for denoising and completing the sinograms while the latter is used to removing the noise and artifacts of the CT images. Experimental results show that the reconstructed CT images by our methods have the highest PSNR and SSIM in average compared to state of the art methods. Copyright © 2020, The Authors. All rights reserved.

关键词： computerized tomography

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A Comparison Study of Tracking Differentiator and Robust Exact Differentiator

A Comparison Study of Tracking Differentiator and Robust Exa...

引用

Chinese Automation Congress (CAC)

作者： Juan Wang Hehong Zhang Gaoxi Xiao Zhihong Dan Song Zhang Yunde Xie College of Mathematics and Computer Science Fuzhou University Fuzhou China School of Electrical and Electronic Engineering Nanyang Technological University Singapore Singapore Singapore Science and Technology on Altitude Simulation Laboratory AECC Sichuan Gas Turbine Establishment of China Mianyang China Beijing Rail Transit Technology Equipment Group Co. Ltd Beijing China

ISBN: (数字)9781728176871

ISBN: (纸本)9781728176888

This paper presents a comparison study of two commonly-used differentiators, namely tracking differentiator (TD) and robust exact differentiator (RED) in both the frequency and the time domains. Specifically, we compare their performances in filtering and differentiation estimation for a large number of inputs with different levels of noises. Meanwhile, the parameter adaptability regarding different inputs for the two differentiators is tested. Furthermore, the efficiency of the two algorithms are evaluated respectively by the hardware. The results show that TD outperforms RED in quickness, smoothness, and noise-tolerance with no overshoots, while RED has advantageous exactness and robustness in the filtering and algorithm's simplicity. Also, TD has a better parameter adaptability and tolerance to signal frequency's variations whereas the performance of RED is heavily dependent on parameter setting. To overcome the overshoot problem in RED, an enhancement by adoption of the transition function is proposed. These results shall provide useful tips for selecting appropriate differentiators in real-life engineering, and designing new differentiators as well.

关键词： Estimation Signal to noise ratio Time-frequency analysis Time-domain analysis Signal processing algorithms Frequency estimation Turbines

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Coherent mode-combined ultra-narrow-linewidth single-mode micro-disk laser

arXiv

引用

arXiv 2021年

作者： Lin, Jintian Farajollahi, Saeed Fang, Zhiwei Yao, Ni Gao, Renhong Guan, Jianglin Deng, Li Lu, Tao Wang, Min Zhang, Haisu Fang, Wei Qiao, Lingling Cheng, Ya Shanghai201800 China Department of Electrical and Computer Engineering University of Victoria VictoriaBCV8P 5C2 Canada XXL-The Extreme Optoelectromechanics Laboratory School of Physics and Electronic Science East China Normal University Shanghai200241 China Research Center for Intelligent Sensing Zhejiang Lab Hangzhou311100 China The Interdisciplinary Center for Quantum Information State Key Laboratory of Modern Optical Instrumentation College of Optical Science and Engineering Zhejiang University Hangzhou310027 China State Key Laboratory of Precision Spectroscopy East China Normal University Shanghai200062 China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of Sciences Beijing100049 China Collaborative Innovation Center of Extreme Optics Shanxi University Taiyuan030006 China Collaborative Innovation Center of Light Manipulations and Applications Shandong Normal University Jinan250358 China

Integrated single-mode microlasers with ultra-narrow linewidths play a game-changing role in a broad spectrum of applications ranging from coherent communication and LIDAR to metrology and sensing. Generation of such light sources in a controllable and cost-effective manner remains an outstanding challenge due to the difficulties in the realization of ultrahigh Q active micro-resonators with suppressed mode numbers. Here, we report a microlaser generated in an ultra-high Q Erbium doped lithium niobate (LN) micro-disk. Through the formation of coherently combined polygon modes at both pump and laser wavelengths, the microlaser exhibits single mode operation with an ultra-narrow-linewidth of 98 Hz. In combination with the superior electro-optic and nonlinear optical properties of LN crystal, the mass-producible on-chip single-mode microlaser will provide an essential building block for the photonic integrated circuits demanding high precision frequency control and reconfigurability. © 2021, CC BY.

关键词： Optical properties

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Precise assembly and joining of silver nanowires in three dimensions for highly conductive composite structures

引用

International Journal of Extreme Manufacturing 2019年第2期1卷 88-102页

作者： Ying Liu Wei Xiong Da Wei Li Yao Lu Xi Huang Huan Liu Li Sha Fan Lan Jiang Jean-François Silvain Yong Feng Lu Department of Electrical and Computer Engineering University of Nebraska-LincolnLincolnNE 68588-0511United States of America Wuhan National Laboratory for Optoelectronics Huazhong University of Science and Technology1037 Luoyu RoadWuhan 430074People’s Republic of China School of Mechanical Engineering Beijing Institute of TechnologyBeijing100081People’s Republic of China Institut de Chimie de la Matière Condensée de Bordeaux Avenue du Docteur Albert SchweitzerF-33608 Pessac CedexFrance

Three-dimensional(3D)electrically conductive micro/nanostructures are now a key component in a broad range of research and industry *** this work,a novel method is developed to realize metallic 3D micro/nanostructures with silver-thiol-acrylate composites via two-photon polymerization followed by femtosecond laser *** 3D micro/nanoscale conductive structures have been successfully fabricated with∼200 nm *** loading of silver nanowires(AgNWs)and joining of junctions successfully enhance the electrical conductivity of the composites from insulating to 92.9 Sm^−1 at room ***,for the first time,a reversible switching to a higher conductivity is observed,up to∼10^5Sm^−1 at 523 *** temperature-dependent conductivity of the composite is analyzed following the variable range hopping and thermal activation *** nanomaterial assembly and joining method demonstrated in this study pave a way towards a wide range of device applications,including 3D electronics,sensors,memristors,micro/nanoelectromechanical systems,and biomedical devices,etc.

关键词： precise assembly joining silver nanowires nanofabrication three dimensional

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