检索结果-内蒙古大学图书馆

Exploring high transition temperature topological superconductivity in (Li1−xCoxOH)CoSb superlattices

Physical Review B 2020年第17期102卷 174513-174513页

作者： M. U. Muzaffar Wenjun Ding Shunhong Zhang Ping Cui Zhenyu Zhang International Center for Quantum Design of Functional Materials (ICQD) Hefei National Laboratory for Physical Sciences at Microscale (HFNL) and CAS Center for Excellence in Quantum Information and Quantum Physics 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

Among the FeSe-based superconductors, (Li1−xFexOH)FeSe has been discovered as an air-stable superlattice structure harboring both high transition temperature (high-Tc) superconductivity and intriguing topological superconducting properties. Here, we use first-principles approaches to identify a chemically isovalent and structurally identical counterpart of (Li1−xFexOH)FeSe, namely, (Li1−xCoxOH)CoSb, which not only is an attractive candidate to harbor high-Tc superconductivity, but also exhibits two distinct features surrounding topology and magnetism. The rationale of this predictive design is based on the recent identification of CoSb as a layered high-Tc superconductor stabilized on SrTiO3. We first show that the superlattice structures of (Li1−xCoxOH)CoSb (x=0 or 0.25) are dynamically and thermodynamically stable. Next, we demonstrate that (Li1−xCoxOH)CoSb possesses superior superconducting properties to (Li1−xFexOH)FeSe, offering an appealing platform for realizing high-Tc superconductivity beyond the Cu- and Fe-based superconducting systems. More strikingly, we find that (LiOH)CoSb is already topologically nontrivial even without extrinsic doping in the spacer layers, thereby offering a cleaner and more ideal candidate system for realizing topological superconductivity. Furthermore, (Li1−xCoxOH)CoSb exhibits weaker elemental magnetic moments than (Li1−xFexOH)FeSe, which may provide a different angle for elucidating the microscopic mechanisms of superconductivity in these and related systems.

关键词： Superconductivity Topological superconductors High-temperature superconductors Iron-based superconductors First-principles calculations Wannier function methods

来源：评论

学校读者我要写书评

暂无评论

Corrigendum to “Co-deposition characteristics of hydrates and sands in gas-salty water-sands flow system” [Fuel 346 (2023) 128276]

引用

Fuel 2023年 352卷

作者： Lihao Liu Bohui Shi Shangfei Song Yuchuan Chen Xinhao Luo Shijia Zhang Huirong Huang Haiyuan Yao Guangjin Chen Jing Gong National Engineering Laboratory for Pipeline Safety/ MOE Key Laboratory of Petroleum Engineering/Beijing Key Laboratory of Urban Oil and Gas Distribution Technology China University of Petroleum-Beijing Beijing 102200 China State Key Laboratory of Natural Gas Hydrates Beijing 100028 China China’s Oil and Gas Exploration and Development Company Beijing 100034 China CNOOC EnerTech Equipment Technology Research & Design Center Tianjin 300452 China School of Petroleum Engineering Chongqing University of Science & Technology Chongqing 401331 China CNOOC Research Institute Ltd. Beijing 100028 China

来源：评论

学校读者我要写书评

暂无评论

Analysis of the Axial Fan Performance Mounted on a 4.5kW Aviation Motor

引用

Journal of Physics: Conference Series 2021年第1期1820卷

作者： Bin Liu Zhongjun Yu Jia Fu Zutao Chen National Key Laboratory of Science and Technology on Vessel Integrated Power System Naval University of Engineering Wuhan 430033 China

Integrating an axial flow fan with the rotor is a sufficient cooling method for high-speed and high power density motors. Different from the axial fan design work under ideal intake condition, i.e. the intake flow of the fan is axial and uniform, the flow in actual engineering is more complex, which means the flow characteristics of an integrated fan are changed and disturbed. It leads to a performance penalty of the fan, and in some conditions it makes the fan stall, so it is important to get a knowledge of the flow characteristics and the performance of the integrated fan. A certain 4.5kW aviation motor with integrated axial fan is taken as the research object. Firstly, the motor-fan coupling simulation model and ideal axial intake simulation model are established, in which the mass flow rates are same, then calculation is conducted. Secondly, the simulation results are analyzed and compared, focusing on the performance of the axial fan, especially the static pressure rise, and the conclusion is obtained that the static pressure rise in ideal axial intake situation is higher than that in coupling situation. Furthermore, the reasons for the characteristics change are explored, finding that the increase of flow turbulence due to the more complex wind road structure is the main cause for these changes. This paper investigates the flow characteristics and axial fan performance mounted a whole motor, making a contribution to better understand the changes in fan performance under motor-fan coupling situation.

关键词：

来源：评论

学校读者我要写书评

暂无评论

An Approach on Visual Detecting Multi-Targets in the Unstructured and Complex Scenes Based on RGB-D Images

An Approach on Visual Detecting Multi-Targets in the Unstruc...

引用

Automation, Control and Robotics Engineering (CACRE), International Conference on

作者： Qimeng Tan Yikun Sun Pengfei Xin Yimin Lin Chao Ma Xinyu Wang Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing Institute of Spacecraft System Engineering Propellant Injection Laboratory Beijing Special Engineering Design and Research Institute Institute of Optical Communication &Optoelectronics Beijing University of Posts &Telecommunications School of Instrument Science and Optoelectronic Engineering Beijing Information Science and Technology University

ISBN: (数字)9781728198880

ISBN: (纸本)9781728198897

The technology of detecting and identifying multitarget is of significance for robotic visual navigation within the unknown, unstructured, complex scenes, whose result could be considered as important references of 3 D map building and path planning for mobile robot. Traditional algorithms of target detection can be applied to 2 D images without depth information generally, which is disturbed by few factors such as illumination, view and scale easily. Therefore, an approach on visual detecting multi-target of unstructured and complex scenes based on RGBD images is proposed in this article to solve the above problem, which is composed of extracting descriptor of rotation and scale invariance feature, local encoding of targets, random ferns classifier training, Hough map generation, Hough voting theoretical model and local maximum search. Experimental results have shown that the proposed approach reduce the calculation of extracting and matching local feature, improve the accuracy of object recognition and detection in unknown complex environments, be capable of well robust against few disturbing factors i.e. rotation, scale, illumination, occlusion and non-rigid body deformation.

关键词： Robotic Visual Navigation RGB-D Image Target Detection RFC(Random Ferns Classifier) RSI-LBF(Rotation and Scale Invariance-Local Binary Feature)

来源：评论

学校读者我要写书评

暂无评论

sCompile: Critical Path Identification and Analysis for Smart Contracts 21st

sCompile: Critical Path Identification and Analysis for Smar...

引用

21st International Conference on Formal Engineering Methods, ICFEM 2019

作者： Chang, Jialiang Gao, Bo Xiao, Hao Sun, Jun Cai, Yan Yang, Zijiang Department of Computer Science Western Michigan University KalamazooMI49009 United States Pillar of Information System Technology and Design Singapore University of Technology and Design Singapore Singapore School of Information Systems Singapore Management University Singapore Singapore State Key Laboratory of Computer Science Institute of Software Chinese Academy of Sciences Beijing China

ISBN: (纸本)9783030324087

Ethereum smart contracts are an innovation built on top of the blockchain technology, which provides a platform for automatically executing contracts in an anonymous, distributed, and trusted way. The problem is magnified by the fact that smart contracts, unlike ordinary programs, cannot be patched easily once deployed. It is important for smart contracts to be checked against potential vulnerabilities. In this work, we propose an alternative approach to automatically identify critical program paths (with multiple function calls including inter-contract function calls) in a smart contract, rank the paths according to their criticalness, discard them if they are infeasible or otherwise present them with user friendly warnings for user inspection. We identify paths which involve monetary transaction as critical paths, and prioritize those which potentially violate important properties. For scalability, symbolic execution techniques are only applied to top ranked critical paths. Our approach has been implemented in a tool called sCompile, which has been applied to 36,099 smart contracts. The experiment results show that sCompile is efficient, i.e., 5 s on average for one smart contract. Furthermore, we show that many known vulnerabilities can be captured if user inspects as few as 10 program paths generated by sCompile. Lastly, sCompile discovered 224 unknown vulnerabilities with a false positive rate of 15.4% before user inspection. © 2019, Springer Nature Switzerland AG.

关键词： Smart contract

来源：评论

学校读者我要写书评

暂无评论

MoSi2N4: An emerging 2D electronic material with protected band edge states and dielectric tunable quasiparticle and optical properties

arXiv

引用

arXiv 2021年

作者： Wu, Yabei Tang, Zhao Xia, Weiyi Gao, Weiwei Jia, Fanhao Zhang, Yubo Zhu, Wenguang Zhang, Wenqing Zhang, Peihong Department of Physics Shenzhen Institute for Quantum Science & Engineering Southern University of Science and Technology Guangdong Shenzhen518055 China Guangdong Provincial Key Lab for Computational Science and Materials Design Shenzhen Municipal Key Lab for Advanced Quantum Materials and Devices Southern University of Science and Technology Guangdong Shenzhen518055 China Icqd Hefei National Laboratory for Physical Science at the Microscale Key Laboratory of Strongly-Coupled Quantum Matter Physics Chinese Academy of Sciences Department of Physics Synergetic Innovation Center of Quantum Information and Quantum Physics University of Science and Technology of China Anhui Hefei230026 China Department of Physics University at Buffalo State University of New York BuffaloNY14260 United States Department of Physics Dalian University of Technology Liaoning Dalian116024 China International Centre for Quantum and Molecular Structures Materials Genome Institute Department of Physics Shanghai University 99 Shangda Road Shanghai200444 China

As it is the case for all low-dimensional materials, the low energy electronic structure of two-dimensional (2D) materials are inherently prone to environmental perturbations. While there are applications (e.g., sensors) that exploit this property, the fact that the band-edge states of 2D materials are susceptible to often unpredictable environmental coupling effects may pose significant challenges to their practical applications in electronic or optoelectronic devices. A 2D material couples with its environment through two mechanisms: local chemical coupling arising from the overlap and hybridization of wave functions, and nonlocal dielectric screening effects that renormalize the Coulomb interaction in the system. The local chemical coupling, which may arise from the (often unintentional) surface adsorption or interfacial chemical coupling, is difficult to predict or control experimentally. Nonlocal dielectric screening effects, on the other hand, can be tuned by choosing the substrates or layer thickness in a controllable manner. Therefore, a compelling 2D electronic material should offer band edge states that are robust against local chemical coupling effects. Here we demonstrate that the recently synthesized MoSi2N4is an ideal 2D semiconductor with robust band edge states protected from capricious environmental chemical coupling effects. We have carried out thorough density functional theory (DFT) and many-body perturbation theory (MBPT) calculations to illustrate how the band edge states of MoSi2N4are essentially shielded from direct chemical coupling to its environment, and, at the same time, the quasiparticle and optical properties of MoSi2N4can be modulated through the nonlocal dielectric screening effects. This unique property, together with the moderate band gap and the thermodynamic and mechanical stability of this material, may pave the way for a range of applications in areas including energy, 2D electronics, and optoelectronics. Copyright © 2021, The

关键词： Mechanical stability

来源：评论

学校读者我要写书评

暂无评论

Energy Management and Trajectory Optimization for UAV-Enabled Legitimate Monitoring systems

arXiv

引用

arXiv 2020年

作者： Hu, Shuyan Wu, Qingqing Wang, Xin State Key Laboratory of ASIC and System School of Information Science and Technology Fudan University Shanghai200433 China Department of Electrical and Computer Engineering National University of Singapore Singapore119077 Singapore State Key Laboratory of ASIC and System Shanghai Institute for Advanced Communication and Data Science Department of Communication Science and Engineering Fudan University Shanghai200433 China

Thanks to their quick placement and high flexibility, unmanned aerial vehicles (UAVs) can be very useful in the current and future wireless communication systems. With a growing number of smart devices and infrastructure-free communication networks, it is necessary to legitimately monitor these networks to prevent crimes. In this paper, a novel framework is proposed to exploit the flexibility of the UAV for legitimate monitoring via joint trajectory design and energy management. The system includes a suspicious transmission link with a terrestrial transmitter and a terrestrial receiver, and a UAV to monitor the suspicious link. The UAV can adjust its positions and send jamming signal to the suspicious receiver to ensure successful eavesdropping. Based on this model, we first develop an approach to minimize the overall jamming energy consumption of the UAV. Building on a judicious (re)formulation, an alternating optimization approach is developed to compute a locally optimal solution in polynomial time. Furthermore, we model and include the propulsion power to minimize the overall energy consumption of the UAV. Leveraging the successive convex approximation method, an effective iterative approach is developed to find a feasible solution fulfilling the Karush-Kuhn-Tucker (KKT) conditions. Extensive numerical results are provided to verify the merits of the proposed schemes. Copyright © 2020, The Authors. All rights reserved.

关键词： Unmanned aerial vehicles (UAV)

来源：评论

学校读者我要写书评

暂无评论

Impact analysis of different auxiliary heat sources on the dynamic performance of a solar seasonal heat storage and heating system

引用

Applied Thermal Engineering 2025年 276卷

作者： Bo Dong Mingfei He Bo Huang Bo Song Key Laboratory of Thermo-Fluid Science and Engineering Ministry of Education School of Energy and Power Engineering Xi’an Jiaotong University Xi’an Shaanxi 710049 China National Key Laboratory of Nuclear Reactor Technology Nuclear Power Institute of China Chengdu 610213 China School of Energy and Materials Shihezi University Shihezi Xinjiang 832000 China Institute of Bingtuan Energy Development Research Shihezi University Shihezi Xinjiang 832000 China Institute of Electrical Engineering Chinese Academy of Sciences Beijing 100190 China

The solar seasonal heat storage technique is a promising solution to solve the mismatch between the summer solar energy collection and the winter heating demand. The energy level of the heat stored is not high and most of it cannot be used directly for building heating. This leads to the obvious waste of thermal energy and the overall efficiency of the storage system becomes low. In this work, two simulation models of solar seasonal thermal storage heating systems with heat pumps and boilers as auxiliary heat sources were built in TRNSYS and time-step independent verification was performed. In addition, the correctness of the TRNSYS models is verified using the available experimental data. It is showed that the experimental data agree well with the simulation values of this work. The performances of the two different systems are evaluated based on several key indicators including solar collector efficiency, heat storage efficiency, energy consumption, and solar assurance rate. At the end of the first operation year, the investigations reveal that: (1) The effective heat collection rate of the heat pump system is 50 % higher than that of the boiler system. (2) The solar energy guarantee rate of the heat pump system is 44 % higher than that of the boiler system. (3) The fossil energy consumption of the heat pump system is 74 % lower than that of the boiler system. (4) The temperature distribution and the heat loss of the storage tanks are almost the same for the two systems. The long-cycle simulation is also performed and it is indicated that the heat pump system becomes steady since the third year of operations.

关键词： Heat pump systems

来源：评论

学校读者我要写书评

暂无评论

Approaching the Fundamental Limit of Orbital-Angular-Momentum Multiplexing Through a Hologram Metasurface

引用

Physical Review Applied 2021年第6期16卷 064042-064042页

作者： Shuai S.A. Yuan Jie Wu Menglin L.N. Chen Zhihao Lan Liang Zhang Sheng Sun Zhixiang Huang Xiaoming Chen Shilie Zheng Li Jun Jiang Xianmin Zhang Wei E.I. Sha College of Information Science and Electronic Engineering Zhejiang University Hangzhou 310027 China Department of Education of Anhui Province Ministry of Education and the Key Laboratory of Electromagnetic Environmental Sensing Anhui University Hefei 230039 China Department of Electrical and Electronic Engineering The University of Hong Kong Hong Kong Department of Electronic and Electrical Engineering University College London Torrington Place London WC1E 7JE United Kingdom Anhui Province Key Laboratory of Simulation and Design for Electronic Information System Hefei Normal University Hefei 230601 China School of Electronic Science and Engineering University of Electronic Science and Technology of China Chengdu 611731 China School of Information and Communications Engineering Xi’an Jiaotong University Xi’an 710049 China

Establishing and approaching the fundamental limit of orbital-angular-momentum (OAM) multiplexing are necessary and increasingly urgent for current multiple-input multiple-output research. In this work, we elaborate the fundamental limit in terms of independent scattering channels (or the degrees of freedom of scattered fields) through angular-spectral analysis, in conjunction with a rigorous Green’s function method. The scattering-channel limit is universal for arbitrary spatial-mode multiplexing, which is launched by a planar electromagnetic device, such as antenna, metasurface, etc., with a predefined physical size. As a proof of concept, we demonstrate both theoretically and experimentally the limit by a phase-only metasurface hologram that transforms orthogonal OAM modes to plane-wave modes scattered at critically separated angular-spectral regions. Particularly, a minimax optimization algorithm is applied to suppress angular-spectrum aliasing, achieving good performances in both full-wave simulation and experimental measurement at microwave frequencies. This work offers a theoretical upper bound and corresponding approach route for engineering designs of OAM multiplexing.

关键词： Angular momentum of light Polarization of light Spatial profiles of optical beams Devices Metamaterials Surfaces Holography Light scattering

来源：评论

学校读者我要写书评

暂无评论

Tool Path Generation Method for Three-dimensional Vibration-assisted Machining 16

Tool Path Generation Method for Three-dimensional Vibration-...

引用

16th IEEE International Conference on Mechatronics and Automation, ICMA 2019

作者： Wang, Guilian Lv, Bingrui Liu, Bin Mu, Haozhi Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of Technology China Tianjin Laboratory of Control Theory and Applications in Complicated System Tianjin300384 China School of Electrical and Electronic Engineering Tianjin University of Technology Tianjin300384 China

ISBN: (纸本)9781728116983

In this paper, a new tool path generation method is proposed for the 3D (three-dimensional) vibration-assisted 6-DOF (six degree of freedom) machine tool machining system. The tool feed path is generated by the tangent point method and the coordinate transformation theory. It is worth noting that this method needle is only used when the tool and workpiece surface topography can be mathematically described. Finally, a numeric simulation method is used to simulate the tool path which is required when machining workpiece surfaces with different topography tools. The results show that the tool path generation method is widely applicable to tools and workpieces of various shapes, and it is of great significance to reveal the influences of different tool shapes on the tool path. © 2019 IEEE.

关键词： Machine tools

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：