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Strong Neel ordering and luminescence correlation in a two-dimensional antiferromagnet

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arXiv 2022年

作者： Zhou, Yongheng He, Kaiyue Hu, Huamin Ouyang, Gang Zhu, Chao Wang, Wei Qin, Sichen Tao, Ye Chen, Runfeng Zhang, Le Shi, Run Cheng, Chun Wang, Han Liu, Yanjun Liu, Zheng Wang, Taihong Huang, Wei Wang, Lin Chen, Xiaolong Department of Electrical and Electronic Engineering Southern University of Science and Technology Shenzhen518055 China 30 South Puzhu Road Nanjing211816 China Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Key Laboratory for Matter Microstructure and Function of Hunan Province Hunan Normal University Changsha410081 China SEU-FEI Nano-Pico Center Key Laboratory of MEMS of Ministry of Education Collaborative Innovation Center for Micro/Nano Fabrication Device and System Southeast University Nanjing210096 China School of Materials Science and Engineering Nanyang Technological University Singapore639798 Singapore 127 West Youyi Road Xi'An710072 China Nanjing University of Posts & Telecommunications 9 Wenyuan Road Nanjing210023 China Department of Materials Science and Engineering Southern University of Science and Technology Shenzhen518055 China

Magneto-optical effect has been widely used in light modulation, optical sensing and information storage. Recently discovered two-dimensional (2D) van der Waals layered magnets are considered as promising platforms for investigating novel magneto-optical phenomena and devices, due to the long-range magnetic ordering down to atomically-thin thickness, rich species and tunable properties. However, majority 2D antiferromagnets suffer from low luminescence efficiency which hinders their magneto-optical investigations and applications. Here, we uncover strong light-magnetic ordering interactions in 2D antiferromagnetic MnPS3 utilizing a newly-emerged near-infrared photoluminescence (PL) mode far below its intrinsic bandgap. This ingap PL mode shows strong correlation with the Neel ordering and persists down to monolayer thickness. Combining the DFT, STEM and XPS, we illustrate the origin of the PL mode and its correlation with Neel ordering, which can be attributed to the oxygen ion-mediated states. Moreover, the PL strength can be further tuned and enhanced using ultraviolet-ozone treatment. Our studies offer an effective approach to investigate light-magnetic ordering interactions in 2D antiferromagnetic semiconductors. © 2022, CC BY-NC-SA.

关键词： Manganese compounds

An Improved Convolutional Neural Network for Monocular Depth Estimation 9th

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An Improved Convolutional Neural Network for Monocular Depth...

9th International Conference on Green Intelligent Transportation systems and Safety, 2018

作者： Kang, Jing Dang, Anrong Zhang, Bailing Wang, Yongming Su, Hang Su, Fei Ci, Tianyu Wang, Fangping China Transport Telecommunications & Information Center Beijing China Department of Urban Planning School of Architecture Tsinghua University Beijing China Institute for China Sustainable Urbanization Tsinghua University Beijing China Department of Mechanical & Electronic Engineering China University of Mining & Technology Beijing China College of Global Change and Earth System Science Beijing Normal University Beijing China

ISBN: (纸本)9789811506437

Depth estimation from monocular image plays an essential role in artificial intelligence, which is one of the important ways for sensing the operating environment in automatic-driving system or advanced driving assistant system. The most recent approaches have gained significant improvement for depth prediction based on convolutional neural networks (CNNs). In this paper, a novel framework of CNNs is proposed for monocular depth estimation based on deep ordinal regression network (DORN) and a U-net structure. The new model is trained, verified in process and tested on 5000 images from a simulation experiment platform provide by "Grand Theft Auto". To eliminate or at least largely reduce the impact from ground truth with no depth values, three different training strategies were employed for network optimization. We developed an effective weighted training strategy for depth prediction to improve the estimation accuracy. The comparison of evaluations over our results and DORN demonstrated the effectiveness of our method. The results showed that the proposed method achieved state-of-the-art performances. © 2020, Springer Nature Singapore Pte Ltd.

关键词： Image classification

Energy-Efficient Cell-Free Massive MIMO Through Sparse Large-Scale Fading Processing

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arXiv 2022年

作者： Chen, Shuaifei Zhang, Jiayi Björnson, Emil Demir, Özlem Tuğfe Ai, Bo The School of Electronic and Information Engineering The Frontiers Science Center for Smart Highspeed Railway System Beijing Jiaotong University Beijing100044 China Purple Mountain Laboratories Nanjing211111 China The Department of Computer Science KTH Royal Institute of Technology Kista164 40 Sweden The Department of Electrical and Electronics Engineering TOBB University of Economics and Technology Ankara Turkey The State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing100044 China The Henan Joint International Research Laboratory of Intelligent Networking and Data Analysis Zhengzhou University Zhengzhou450001 China

Cell-free massive multiple-input multiple-output (CF mMIMO) systems serve the user equipments (UEs) by geographically distributed access points (APs) by means of joint transmission and reception. To limit the power consumption due to fronthaul signaling and processing, each UE should only be served by a subset of the APs, but it is hard to identify that subset. Previous works have tackled this combinatorial problem heuristically. In this paper, we propose a sparse distributed processing design for CF mMIMO, where the AP-UE association and long-term signal processing coefficients are jointly optimized. We formulate two sparsity-inducing mean-squared error (MSE) minimization problems and solve them by using efficient proximal approaches with block-coordinate descent. For the downlink, more specifically, we develop a virtually optimized large-scale fading precoding (V-LSFP) scheme using uplink-downlink duality. The numerical results show that the proposed sparse processing schemes work well in both uplink and downlink. In particular, they achieve almost the same spectral efficiency as if all APs would serve all UEs, while the energy efficiency is 2-4 times higher thanks to the reduced processing and signaling. Copyright © 2022, The Authors. All rights reserved.

关键词： Energy efficiency

Nonlinear Behavior of Surface Charge Density and Zeta Potential in Microchannel Electrokinetic Flow

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SSRN

SSRN 2023年

作者： Chen, Daming Arancibia-Miranda, Nicolas Escudey, Mauricio Fu, Jiao Lu, Qin Amon, Cristina H. Galatro, Daniela Guzmán, Amador M. Facultad de Ingeniería Departamento de Ingeniería Mecánica Universidad de Santiago de Chile Av. B. O’Higgins 3363 Santiago9170020 Chile Center for the Development of Nanoscience and Nanotechnology CEDENNA Santiago9170124 Chile Facultad de Química y Biología Universidad de Santiago de Chile Av. B. O’Higgins Santiago3363 Chile Xi'an key laboratory of advanced control and intelligent process Xi'an University of Posts and Telecommunications Xi'An710121 China Solar and Thermal Energy Conversion and Storage Device and System Laboratory STECTEC Santiago Chile Escuela de Ingenieria Industrial Facultad de Ingenieria y Ciencias Universidad Diego Portales Ejercito 441 Santiago Chile Department of Mechanical and Industrial Engineering Faculty of Applied Science and Engineering University of Toronto 5 King’s College Road TorontoON Canada Department of Chemical Engineering and Applied Chemistry Faculty of Applied Science and Engineering University of Toronto 200 College Street TorontoON Canada

In this work, a combined numerical and experimental investigation of the surface charge density and zeta potential behavior is investigated for borosilicate immersed in KCl and NaCl electrolytes and for imogolite immersed in KCl, CaCl2, and MgCl2 electrolytes. Simulations and experiments of the electrokinetic flows with electrolyte solutions were performed to accurately determine the electric double layer (EDL), the zeta potential, and the surface charge density at various electrolyte concentrations and pH. The zeta potential was experimentally determined and numerically predicted by solving the coupled governing equations of mass, species, momentum, and electrical field iteratively. The zeta potential for borosilicate develops strong nonlinear behavior with the ion concentration following a power-law. Likewise, the surface charge density obeys a nonlinear behavior, decreasing as the concentration increases. Moreover, for imogolite, both the zeta potential and the surface charge density behave nonlinearly with the pH. The EDL for borosilicate and imogolite becomes thinner as the electrolyte concentration and pH increase;this behavior is caused by increased surface charge density, resulting in the higher attraction of the free charges. The reported nonlinear behavior describes more accurately the interaction of the nanoparticle surface charge with the electrolytes and its effect on the electrolyte transport properties. © 2023, The Authors. All rights reserved.

关键词： Zeta potential

Multiple superconducting phases driven by pressure in the topological insulator GeSb4Te7

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arXiv 2023年

作者： Zhou, W. Li, B. Shen, Y. Feng, J.J. Xu, C.Q. Guo, H.T. He, Z. Qian, B. Zhu, Ziming Xu, Xiaofeng School of Electronic and Information Engineering Changshu Institute of Technology Changshu215500 China Information Physics Research Center Nanjing University of Posts and Telecommunications Nanjing210023 China Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Department of Physics Synergetic Innovation Center for Quantum Effects and Applications Hunan Normal University Changsha410081 China Center for High Pressure Science and Technology Advanced Research Shanghai201203 China School of Physical Science and Technology Ningbo University Ningbo315211 China Department of Applied Physics Zhejiang University of Technology Hangzhou310023 China

Tuning superconductivity in topological materials by means of chemical substitution, electrostatic gating or pressure is thought to be an effective route towards realizing topological superconductivity with their inherent Majorana fermions, the manipulation of which may form the basis for future topological quantum computing. It has recently been established that the pseudo-binary chalcogenides (ACh)m(Pn2Ch3)n (A = Ge, Mn, Pb, etc.;Pn = Sb or Bi;Ch= Te, Se) may host novel topological quantum states such as the quantum anomalous Hall effect and topological axion states. Here we map out the phase diagram of one member in this series, the topological insulator candidate GeSb4Te7 up to pressures of ∼35 GPa, through a combination of electrical resistance measurements, Raman spectroscopy as well as first-principles calculations. Three distinct superconducting phases emerge under the pressure above ∼11 GPa, ∼17 GPa and ∼31 GPa, which are accompanied by concomitant structural transitions, evidenced from the changes in the Raman modes. The first-principles calculations validate the existence of a topological insulating state at ambient pressure and predict two possible structural transitions at 10 GPa and 17 GPa, in agreement with the experimental observations. Overall, our results establish the GeSb4Te7 family of materials as a fertile arena for further exploring various topological phenomena, including topological phase transitions and putative topological superconductivity. © 2023, CC BY.

关键词： Germanium alloys

Low Power CMOS Thermal and Tamper Sensor for Smart Cards Protection 20

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Low Power CMOS Thermal and Tamper Sensor for Smart Cards Pro...

20th International Conference on Electromagnetics in Advanced Applications, ICEAA 2018

作者： Cartagena, Luis Q Barbin, Silvio E Department of Electronic System Engineering and Telecommunications and Control Engineering Polytechnic School of the University of Sao Paulo Brazil

ISBN: (纸本)9781538667620

In this paper, we present a new design of a tamper resistance and a temperature sensor protection in Smart Cards to prevent both, physical and security attacks in the corners of their operating temperature range. Physical attacks are used for reverse engineering and temperature attacks normally result in malfunctions in the smart card processor, allowing the access to extra information. The purpose of this design is the protection of the chip of smart cards in a temperature range of -20 °C to 120 °C, and tamper resistance with a small area and low power consumption circuit. The sensor and tamper resistance were designed in Cadence using the system on a Chip (SoC) concept, employing a standard 90 nm CMOS technology that operates on a power supply voltage of 1.2 V. The obtained results show effective protection at the corners of the -40 °C to 140 °C temperature range and Vdd = 1.2 V 10%. This new circuit design can effectively work as an excellent protector against security manipulation of Smart Cards. © 2018 IEEE.

关键词： Smart cards

Kinematic feature-based evaluation method for elderly balance ability by using factor analysis 1

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2nd Chinese Conference on Pattern Recognition and Computer Vision, PRCV 2019

作者： Ming, Rui Xing-Rong, Fan Xu, Guoliang Chongqing Engineering Laboratory for Detection Control and Integrated System Chongqing Technology and Business University Chongqing400067 China College of Communication and Information Engineering Chongqing University of Posts and Telecommunications Chongqing400065 China Electronic Information and Networking Research Institute Chongqing University of Posts and Telecommunications Chongqing400065 China

ISBN: (数字)9783030317263

ISBN: (纸本)9783030317256

Modeling and assessing balance ability for elderly people is an important and realistic task with a view to assisting them in mobility status, correcting postures and preventing accidental falling. The aim of this study was to develop a novel kinematic feature-based evaluation method for elderly balance ability by using factor analysis. Based on the kinematics, twenty-five feature indicators were first extracted from walking gait data, which were collected by deploying twenty-four monitoring points on the body of the elderly subjects. Then, two main factors were identified by using factor analysis that affect the walking balance ability of the elderly, and the comprehensive evaluation scoring model of the elderly balance ability was constructed. Finally, real data from all the elderly subjects in free walking state were used to validate our method. The results of empirical analysis confirm the validity and usefulness of the proposed method. © Springer Nature Switzerland AG 2019.

关键词： Kinematics

Reconfigurable Intelligent Surface (RIS)-aided Vehicular Networks: Their Protocols, Resource Allocation, and Performance

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arXiv 2022年

作者： Chen, Yuanbin Wang, Ying Zhang, Jiayi Zhang, Ping Hanzo, Lajos State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing100876 China The School of Electronic and Information Engineering Beijing Jiaotong University Beijing100044 China The Frontiers Science Center for Smart High-speed Railway System Beijing Jiaotong University Beijing100044 China The State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing100876 China The Department of Broadband Communication Peng Cheng Laboratory Shenzhen518055 China The Department of Electronics and Computer Science University of Southampton SouthamptonSO17 1BJ United Kingdom

Reconfigurable intelligent surfaces (RISs) assist in paving the way for the evolution of conventional vehicular networks to autonomous driving. Having said that, the 3rd Generation Partnership Project (3GPP) faces numerous open challenges concerning the RIS-aided vehicle-to-everything (V2X) solutions of the near future. To tackle these challenges and to stimulate future research, this article focuses on the prospective transmission design of RIS-aided V2X communications. In particular, two V2X sidelink modes are enhanced by exploiting RISs and their variants, followed by a customized transmission frame structure that partitions the transmission efforts into different phases. Next, effective channel tracking and resource allocation techniques are developed for attaining a high beamforming gain at low overhead and complexity. Finally, promising research topics are highlighted and future 3GPP standardization items are proposed for RIS-aided V2X systems. © 2022, CC BY-NC-ND.

关键词： Vehicle to Everything

Frequency support scheme based on parametrized power curve for de-loaded wind turbine under various wind speed

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arXiv 2021年

作者： Zhong, Cheng Lv, Yueming Li, Huayi Chen, JiKai Li, Yang Key Laboratory of Modern Power System Simulation and Control Renewable Energy Technology （Ministry of Education） Northeast Electric Power University Jilin132012 China Department of Electronic Electrical and Systems Engineering University of Birmingham BirminghamB15 2TT United Kingdom

With increased wind power penetration in modern power systems, wind plants are required to provide frequency support similar to conventional plants. However, for the existing frequency regulation scheme of wind turbines, the control gains in the auxiliary frequency controller are difficult to set because of the compromise of the frequency regulation performance and the stable operation of wind turbines, especially when the wind speed remains variable. This paper proposes a novel frequency regulation scheme (FRS) for de-loaded wind turbines. Instead of an auxiliary frequency controller, frequency support is provided by modifying the parametrized power versus rotor speed (Pw-ωr) curve, including the inertia power versus rotor speed curve and the droop power versus rotor speed curve. The advantage of the proposed scheme is that it does not contain any control gains and generally adapts to different wind speeds. Further, the proposed scheme can work for the whole section of wind speed without wind speed measurement information. The compared simulation results demonstrate the scheme improves the system frequency response while ensuring the stable operation of doubly-fed induction generators (DFIGs)-based variable-speed wind turbines (VSWTs) under various wind conditions. Furthermore, the scheme prevents rotor speed overdeceleration even when the wind speed decreases during frequency regulation control. Copyright © 2021, The Authors. All rights reserved.

关键词： Wind