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arXiv 2022年

作者： Wei, Li Huang, Chongwen Alexandropoulos, George C. Yang, Zhaohui Yang, Jun Sha, Wei E.I. Zhang, Zhaoyang Debbah, Mérouane Yuen, Chau Pillar Singapore University of Technology and Design 487372 Singapore College of Information Science and Electronic Engineering Zhejiang University Hangzhou310027 China International Joint Innovation Center Zhejiang University Haining314400 China Hangzhou310027 China The Department of Informatics and Telecommunications National and Kapodistrian University of Athens Panepistimiopolis Ilissia Athens15784 Greece The Technology Innovation Institute Abu Dhabi United Arab Emirates The State Key Laboratory of Mobile Network and Mobile Multimedia Technology Shenzhen518055 China Wireless Product R&D Institute ZTE Corporation Shenzhen518057 China The College of Information Science and Electronic Engineering Zhejiang University Hangzhou310027 China The Technology Innovation Institute Masdar City Abu Dhabi9639 United Arab Emirates CentraleSupelec University Paris-Saclay Gif-sur-Yvette91192 France

This paper investigates the utilization of triple polarization (TP) for multi-user (MU) holographic multiple-input multi-output surface (HMIMOS) wireless communication systems, targeting at capacity boosting and diversity exploitation without enlarging the antenna array sizes. We specifically consider that both the transmitter and receiver are both equipped with an HMIMOS consisting of compact sub-wavelength TP patch antennas within near-field (NF) regime. To characterize TP MU-HMIMOS systems, a TP NF channel model is constructed using the dyadic Green’s function, whose characteristics are leveraged to design two precoding schemes for mitigating the cross-polarization and inter-user interference contributions. Specifically, a user-cluster-based precoding scheme assigns different users to one of three polarizations at the expense of system’s diversity, and a two-layer precoding scheme removes interference using Gaussian elimination method at high computational cost. The theoretical correlation analysis for HMIMOS in NF region is also investigated, revealing that both the spacing of transmit patch antennas and user distance impact transmit correlation factors. Our numerical results show that the users far from transmit HMIMOS experience higher correlation than those closer within NF regime, resulting in a lower channel capacity. Meanwhile, in terms of channel capacity, TP HMIMOS can almost achieve 1.25 times gain compared with dual-polarized HMIMOS, and 3 times compared with conventional HMIMOS. In addition, the proposed two-layer precoding scheme combined with two-layer power allocation realizes a higher spectral efficiency than other schemes without sacrificing diversity. Copyright © 2022, The Authors. All rights reserved.

关键词： Polarization

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Microscopic Origin of Capillary Force Balance at Contact Line

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Physical Review Letters 2020年第12期124卷 125502-125502页

作者： JingCun Fan Joël De Coninck HengAn Wu FengChao Wang CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern Mechanics CAS Center for Excellence in Complex System Mechanics University of Science and Technology of China Hefei 230027 China Laboratory of Surface and Interfacial Physics (LPSI) University of Mons 7000 Mons Belgium

We investigate the underlying mechanism of capillary force balance at the contact line. In particular, we offer a novel approach to describe and quantify the capillary force on the liquid in coexistence with its vapor phase, which is crucial in wetting and spreading dynamics. Its relation with the interface tension is elucidated. The proposed model is verified by our molecular dynamics simulations over a wide contact angle range. Differences in capillary forces are observed in evaporating droplets on homogeneous and decorated surfaces. Our findings not only provide a theoretical insight into capillary forces at the contact line, but also validate Young’s equation based on a mechanical interpretation.

关键词： Capillary interactions Wetting Liquid-solid interfaces

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Re-Recognizing Fluorescence Quenching Units: Improve Abnormally the Luminescent Efficiency of AIEgens for Fluorescence Sensing, Organelle Targeted Imaging and Photodynamic Therapy

SSRN

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SSRN 2022年

作者： Teng, Muzhou Tong, Jialin Xie, Yili Li, Yumin Li, Zhijia Shan, Guoguang Li, Yin Wan, Qing Wang, Zhiming Liu, Tao The Second Clinical Medical College ofLanzhou University Lanzhou University Second Hospital Key Laboratory of the Digestive System Tumors of Gansu Province Lanzhou China College of Ecology and Environment Yuzhang Normal University Nanchang330103 China Institute of Functional Material Chemistry and National & Local United Engineering Lab for Power Battery Faculty of Chemistry Northeast Normal University Changchun China Molecular Diagnosis and Treatment Center for Infectious Diseases Dermatology Hospital Southern Medical University Guangzhou510091 China School of Materials Science and Engineering Nanchang Hangkong University Nanchang330063 China State Key Laboratory of Luminescent Materials and Devices Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates Center for Aggregation-induced emission South China University of Technology Guangzhou510640 China

Fluorescence quenching phenomenon caused by the heavy atom effect and intramolecular charge transfer (ICT) is a classical and generally recognized photophysical phenomenon. However, its universality is not observed in some special aggregation-induced emission luminogens (AIEgens). Herein, a series of cyanostyrene (CST)-based AIEgens were designed and synthesized by coupling different electronic donors and fluorescent quenching groups at both ends of the CST "bridge". By clear study of structure-properties relationship of materials, the performance of full-wavelength emission from deep blue to far red could be achieved by regulating the excited state. Intriguingly, grafting fluorescent quenching groups of bromine (Br) atom and nitro (NO2) to CSTs resulted in abnormal fluorescence enhancement, which broke the conventional rule of quenching fluorescence brought from the above-mentioned quenching units. In addition, the introduction of quenching groups was beneficial for boosting reactive oxygen species (ROS) generation because of activating intersystem crossing (ISC) channel to produce triplet excitons, effectively. In view of special chemical structure contained alkaline group as well as clear photophysical performances, some representative CST-based emitters were chosen to explore advanced applications such as information encryption, fluorescent sensor chips of detecting hydrogen chloride and biological amines, target simultaneously fluorescent imaging of cellular lysosome and mitochondria, and effective photodynamic therapy (PDT) to treat cancer cells. This work revealed that conventional rule of heavy atom effect and strong ICT effect to quench fluorescence was not suitable for some unique CST-based AIEgens, which played important role in liberating our inherent cognition to design novel special functional materials in the future. © 2022, The Authors. All rights reserved.

关键词： Charge transfer

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Stability and energetics of two-dimensional surface crystals in liquid AuSi thin films and nanoscale droplets

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Physical Review Materials 2021年第7期5卷 074003-074003页

作者： Hailong Wang Mengyuan Wang Alireza Shahabi Alain Karma Moneesh Upmanyu CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern Mechanics CAS Center for Excellence in Complex System Mechanics University of Science and Technology of China Hefei Anhui 230027 China Group for Simulation and Theory of Atomic-Scale Material Phenomena (stAMP) Department of Mechanical and Industrial Engineering Northeastern University Boston Massachusetts 02115 USA Department of Physics Northeastern University Boston Massachusetts 02115 USA

We employ atomic-scale computational frameworks to study the surface crystallization in AuSi films and droplets as a function of composition, temperature, and size. Above the melting point, the surfaces of both thin films and droplets undergo a first-order transition from a two-dimensional (2D) Au2Si crystalline phase to a laterally disordered yet stratified layer. The thin film surfaces exhibit an effective surface tension that increases with temperature and decreases with Si concentration, while for droplets in the size range 10–30 nm, the bulk Laplace pressure alters the surface segregation as it occurs with respect to a strained bulk. Above the transition, the size effect on the surface tension due to the stratified surface layer is small, while the crystalline surface layer below the transition is strained and composed of 2D crystallites separated by extended grain boundary scars that lead to large fluctuations in its energetics. As a specific application, all-atom simulations of AuSi droplets on Si(111) substrate subject to Si surface flux show that the supersaturation dependent surface tension destabilizes the contact line via formation of a precursor wetting film on the solid-vapor interface and has ramifications for size selection during droplet-catalyzed routes for nanowire growth. Our study sheds light on the interplay between stability and energetics of surfaces in this unique class of binary alloys and offers pathways for exploiting their surface structure for varied applications such as catalytic nanocrystal growth, dealloying, and polymer crystallization.

关键词： Crystal forms Growth Interface & surface thermodynamics Nanocrystals Structural phase transition 2-dimensional systems Surfaces Molecular dynamics

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Anionic Chemistry Modulation Enabled Environmental Self-Charging Aqueous Zinc Batteries: The Case of Carbonate Ions

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Angewandte Chemie 2024年第39期136卷

作者： Guangmeng Qu Lu Wang Yongzheng Zhao Dedong Wang Xixi Zhang Bin Wang Fengbo Wang Zhongxin Jing Xijin Xu Liqiang Xu Hongfei Li Key Laboratory of Colloid and Interface Chemistry Ministry of Education School of Chemistry and Chemical Engineering Shandong University Jinan Shandong 250100 P. R. China School of Physics and Technology University of Jinan Jinan Shandong 250022 P. R. China School of System Design and Intelligent Manufacturing Southern University of Science and Technology Shenzhen Guangdong 518055 China

Anionic chemistry modulation represents a promising avenue to enhance the electrochemical performance and unlock versatile applications in cutting-edge energy storage devices. Herein, we propose a methodology that involves anionic chemistry of carbonate anions to tailor the electrochemical oxidation-reduction reactions of bismuth (Bi) electrodes, where the conversion energy barrier for Bi (0) to Bi (III) has been significantly reduced, endowing anionic full batteries with enhanced electrochemical kinetics and chemical self-charging property. The elaborately designed batteries with an air-switch demonstrate rapid self-recharging capabilities, recovering over 80 % of the electrochemical full charging capacity within a remarkably short timeframe of 1 hour and achieving a cumulative self-charging capacity of 5 Ah g −1 . The aqueous self-charging battery strategy induced by carbonate anion, as proposed in this study, holds the potential for extending to various anionic systems, including seawater-based Cl − ion batteries. This work offers a universal framework for advancing next-generation multi-functional power sources.

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The Power Control Method of Data Center Based on Cloud- Edge Collaboration

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Journal of Physics: Conference Series 2021年第1期1754卷

作者： Junjie Zhao Yucheng Hou Liu Liu Feng Xie Xiang Mao Pan Luo Jinxin Wang Zhiqiang Zhang Jiang Deng Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu 610213 China Key Laboratory of the Ministry of Education on Smart Power Grids (Tianjin University) Tianjin 300072 China

Data centers have the characteristics of huge energy consumption and strong power fluctuations. To solve the problem of unstable supply and demand such as frequent power fluctuations in the micro-grid of the data center using renewable energies, this paper establishes a controllable load model of server clusters based on the task migration mechanism by analyzing the various tasks and characteristics of large cloud data centers, as well as edge computing nodes. Through the collaborative optimization control of edge and cloud computing tasks, and dynamically adjusting and migrating the server cluster load, a new data center tie-line power control method is proposed. The results of calculation examples show that the method can achieve power smoothing of large-scale cloud data center tie lines through cloud-edge collaborative control.

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Prediction of MnSiTe3 as an intrinsic layered half-metal

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Physical Review B 2020年第20期101卷 205119-205119页

作者： Dechen Zhang Azizur Rahman Wei Qin Xingxing Li Ping Cui Zengming Zhang Zhenyu Zhang International Center for Quantum Design of Functional Materials (ICQD) Hefei National Laboratory for Physical Sciences at Microscale and CAS Center for Excellence in Quantum Information and Quantum Physics University of Science and Technology of China Hefei Anhui 230026 China Department of Physics University of Science and Technology of China Hefei Anhui 230026 China Hefei National Laboratory for Physical Sciences at Microscale University of Science and Technology of China Hefei Anhui 230026 China Key Laboratory of Strongly-Coupled Quantum Matter Physics Chinese Academy of Sciences School of Physical Sciences University of Science and Technology of China Hefei Anhui 230026 China Center for Physical Experiments University of Science and Technology of China Hefei Anhui 230026 China

Half-metallic materials allow electrons with one spin orientation to conduct through, while completely blocking electrons with the other spin orientation. Here we use a multiscale approach to predict that MnSiTe3 within the transition metal trichalcogenide (TMT) family is an intrinsic layered half-metal both in bulk form and at the ultrathin two-dimensional (2D) limit. We first use first-principles calculations to demonstrate that the system is a van der Waals crystal with weak interlayer coupling, allowing ready separation of a monolayer. Next we show that the half-metallicity of the bulk crystal is preserved also for a freestanding monolayer, with highly desirable ferromagnetic interlayer coupling. The ferromagnetic order of the monolayer is further shown to originate from the interplay of the exchange interaction and Ruderman-Kittel-Kasuya-Yosida coupling mediated by the itinerant carriers, while the singly spin-polarized and long-range nature of the latter is largely responsible for the unusually large next-next-nearest ferromagnetic coupling among the Mn ions. These findings, together with the latest developments surrounding ferromagnetism in 2D TMTs, may offer immense application potentials in nanomagnetic and spintronic devices.

关键词： Electronic structure Exchange interaction Ferromagnetism Magnetism RKKY interaction Half-metals Honeycomb lattice Density functional theory

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A Comparative Study of Neural Network Techniques for Automatic Software Vulnerability Detection

A Comparative Study of Neural Network Techniques for Automat...

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Theoretical Aspects of Software Engineering (TASE)

作者： Gaigai Tang Lianxiao Meng Huiqiang Wang Shuangyin Ren Qiang Wang Lin Yang Weipeng Cao School of computer science and technology Harbin Engineering University Harbin China National Key Laboratory of Science and Technology on Information System Security Institute of System Engineering Chinese Academy of Military Science Beijing China College of Computer Science and Software Engineering Shenzhen University Shenzhen China

Software vulnerabilities are usually caused by design flaws or implementation errors, which could be exploited to cause damage to the security of the system. At present, the most commonly used method for detecting software vulnerabilities is static analysis. Most of the related technologies work based on rules or code similarity (source code level) and rely on manually defined vulnerability features. However, these rules and vulnerability features are difficult to be defined and designed accurately, which makes static analysis face many challenges in practical applications. To alleviate this problem, some researchers have proposed to use neural networks that have the ability of automatic feature extraction to improve the intelligence of detection. However, there are many types of neural networks, and different data preprocessing methods will have a significant impact on model performance. It is a great challenge for engineers and researchers to choose a proper neural network and data preprocessing method for a given problem. To solve this problem, we have conducted extensive experiments to test the performance of the two most typical neural networks (i.e., Bi-LSTM and RVFL) with the two most classical data preprocessing methods (i.e., the vector representation and the program symbolization methods) on software vulnerability detection problems and obtained a series of interesting research conclusions, which can provide valuable guidelines for researchers and engineers. Specifically, we found that 1) the training speed of RVFL is always faster than Bi-LSTM, but the prediction accuracy of Bi-LSTM model is higher than RVFL; 2) using doc2vec for vector representation can make the model have faster training speed and generalization ability than using word2vec; and 3) multi-level symbolization is helpful to improve the precision of neural network models.

关键词： Training Neural networks Data preprocessing Static analysis Predictive models Feature extraction Software

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Experimental investigation of abnormal transverse flow enhancement of α particles in heavy-ion collisions

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Physical Review C 2021年第4期104卷 044611-044611页

作者： Y. Huang W. Lin H. Zheng R. Wada A. Bonasera Z. Chen J. Han R. Han M. Huang K. Hagel T. Keutgen X. Liu Y. G. Ma C. W. Ma Z. Majka G. Qu L. Qin P. Ren G. Tian J. Wang Z. Yang J. B. Natowitz Key Laboratory of Radiation Physics and Technology of the Ministry of Education Sichuan University Chengdu 610064 China School of Physics and Information Technology Shaanxi Normal University Xi'an 710119 China Cyclotron Institute Texas A&M University College Station Texas 77843 USA School of Physics Henan Normal University Xinxiang 453007 China Laboratori Nazionali del Sud INFNvia Santa Sofia 62 95123 Catania Italy Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China College of Physics and Electronics Information Inner Mongolia University for Nationalities Tongliao 028000 China FNRS and IPN Université Catholique de Louvain B-1348 Louvain-Neuve Belgium Key Laboratory of Nuclear Physics and Ion-Beam Application (MOE) Institute of Modern Physics Fudan University Shanghai 200433 China Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China Jagiellonian University Krakow Poland School of Science Huzhou University Huzhou 313000 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu 610213 China

The mass dependence of the transverse flow for Z=1–5 fragments from the collisions of Ar40+Al27, Ar40+Ti48, and Ar40+Ni58 at 47 MeV/nucleon is investigated experimentally in this article. The transverse flow values are determined using the in-plane components of the fragment transverse momenta, where three conventional methods, i.e., the kinetic flow tensor method, the transverse momentum analysis method, and the azimuthal correlation method, are applied to reconstruct the reaction plane in an event-by-event basis. It is demonstrated from the comparison of the present experimental mass dependent flow measurements and the model simulations using an improved antisymmetrized molecular dynamics model that the experimentally observed abnormal α transverse flow enhancement is closely related to the reaction plane reconstruction procedure in the flow extraction. We further investigate the physical existence of the abnormal α flow behavior using a two-particle azimuthal correlation method, which allows us to provide the relative flow magnitude information with an identification of fragment charge number without the knowledge of the reaction plane differing from the three conventional methods. It is found that the relative flow magnitudes deduced from the two-particle azimuthal correlation functions with an identification of Z, with the correction for the recoil effect imposed by the momentum conservation, show a monotonically increasing trend as a function of fragment charge number, with no exception of the α flow enhancement. These results, in addition to those from the improved antisymmetrized molecular dynamics model simulations, definitely provide experimental evidences for the inexistence of the abnormal α flow behavior in the heavy-ion collisions at the present incident energy region in nature.

关键词： Collective flow Low & intermediate energy heavy-ion reactions Nuclear reaction analysis

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Research on active disturbance rejection control method for electro-hydraulic servo loading system with considering clearance disturbance 8

Research on active disturbance rejection control method for ...

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8th IEEE International Conference on Fluid Power and Mechatronics, FPM 2019

作者： Chen, Qiang Yang, Fang Liu, Dan-Dan Xue, Yu-Jun Henan University of Science Technology School of Mechatronics Engineering Luoyang China Henan University of Science Technology Henan Key Laboratory of Mechanical Design and Transmission System Luoyang China Luoyang LYC Rearing Co. Ltd Luoyang China

ISBN: (纸本)9781728103112

In the test of high-speed rail bearings, the electro- hydraulic servo-loading system is commonly used to simulate the actual alternating loading for the bearing. Due to the existence of the loading mechanism clearance and the transmission shaft system matching clearance, the loading system has a certain nonlinear displacement disturbance. Combined with the nonlinear characteristics of the electro-hydraulic servo system, the dynamic response characteristics and steady-state control accuracy of the force loading are seriously affected. To this end, the Active Disturbance Rejection control (ADRC) method is used to identify and compensate the gap disturbances using the feedback information of the extended state observer, and the tracking differentiator and feedback control rate are designed to improve the system response speed and suppress overshoot. The control method is applied to the control model of high-speed rail bearing electro-hydraulic servo-loading system. The simulation results show that the control method can achieve good control effect, and the anti-disturbance capability, response speed and steady-state performance of the system are significantly improved. © 2019 IEEE.

关键词： Disturbance rejection

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