检索结果-内蒙古大学图书馆

SSRN 2022年

作者： Hu, Lin Li, Gen Wu, Ning Lin, Miao Bo, Ying Wang, Fang School of Automotive and Mechanical Engineering Changsha University of Science and Technology Changsha China Hunan Province Key Laboratory of Safety Design and Reliability Technology for Engineering Vehicle Changsha University of Science and Technology Changsha China Traffic Engineering and Management Ruhr-University Bochum Germany China Automobile Technology Research Center Co. Ltd Tianjin China China Society of Automotive Engineers Beijing China

Autonomous vehicles (AVs) after fully tested can effectively reduce the accident rate of two-wheelers (TWs), for which the development of test scenarios is one of basic prerequisites. The existing TW test scenarios are difficult to deploy in the simulation software because the details like accident location are ignored. In this study, the typical TW test scenarios at intersections (crossroads or T-junctions) were developed using accident data from China In-Depth Accident Study (CIDAS). First, 1239 TWs accidents involving intersection were selected from CIDAS, and the correlation analysis was carried out for road type, TW type, weather, accident time, traffic light, and other thirteen variables. Second, the bi-level clustering structure based on k-medoids algorithm was used in this study, in which the first level was used to merge variables with high correlation and the second for mining typical accident scenarios. Third, the scenario injury index based on weight coefficient was proposed, and scenarios with high-frequency and high injury index were extracted. The four main conclusions are as follows: (1) Many scenarios not found in previous studies have been developed, which involving retrograde ETWs, ETWs crossing the road through the sidewalk, and crossroad equipped with traffic lights;(2) Two high frequency scenarios and four scenarios with high injury index were obtained. Motorcycle scenarios have lower frequency than electric two-wheeler (ETW), but with higher injury index due to high velocity;(3) The vehicles are mainly turning at T-junction scenarios, while traveling straight at the crossroad;(4) Future research on test scenarios should focus on some special situations, such as: Failure to give way, Retrograde TWs, Traffic light conflict including jumping the red light and traffic light switching gap, and visual obstruction. The research methods and conclusions can be used as guidelines or references for AVs test based on scenario. © 2022, The Authors. All rig

关键词： Autonomous vehicles

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Investigation of β-Ga2O3 films and β-Ga2O3/GaN heterostructures grown by metal organic chemical vapor deposition

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science China(Physics,Mechanics & Astronomy) 2020年第11期63卷 98-102页

作者： YaChao Zhang YiFan Li ZhiZhe Wang Rui Guo ShengRui Xu ChuanYang Liu ShengLei Zhao JinCheng Zhang Yue Hao State Key Discipline Laboratory of Wide Band Gap Semiconductor Technology School of MicroelectronicsXidian UniversityXi’an 710071China China Electronic Product Reliability and Environmental Testing Research Institute Guangzhou 510610China School of Electronic and Information Engineering Suzhou University of Science and TechnologySuzhou 215009China

In this work,(-201)β-Ga2O3 films are grown on GaN substrate by metal organic chemical vapor deposition(MOCVD).It is revealed that theβ-Ga2O3 film grown on GaN possesses superior crystal quality,material homogeneity and surface morphology than the results of common heteroepitaxialβ-Ga2O3 film based on sapphire ***,the relevance between the crystal quality of epitaxialβ-Ga2O3 film and theβ-Ga2O3/GaN interface behavior is *** electron microscopy result indicates that the interface atom refactoring phenomenon is beneficial to relieve the mismatch strain and improve the crystal quality of subsequentβ-Ga2O3 ***,the energy band structure ofβ-Ga2O3/GaN heterostructure grown by MOCVD is investigated by X-ray photoelectron spectroscopy and a large conduction band offset of 0.89 eV is *** results in this work not only convincingly demonstrate the advantages ofβ-Ga2O3 films grown on GaN substrate,but also show the great application potential of MOCVDβ-Ga2O3/GaN heterostructures in microelectronic applications.

关键词： β-Ga2O3 GaN substrate MOCVD interface band structure

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reliability evaluation of multi-state load sharing effect via FM cumulative model

Reliability evaluation of multi-state load sharing effect vi...

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12th International Conference on Quality, reliability, Risk, Maintenance, and Safety engineering (QR2MSE 2022)

作者： C. Ye Y. Wang Y. Chen CRSC Research & Design Institute Group Co. Ltd. Beijing People's Republic of China Science and Technology on Reliability and Environmental Engineering Laboratory Beihang University Beijing People's Republic of China

Load sharing effect is functional dependency in k-out-n system. The cumulative loading history model has been widely studied in binary state load sharing effect, however, there are few studies to describe the cumulative loading effect for multi-state cases. When a system performs tasks of multiple efficiency levels, it usually presents a certain number of performance degradation states. Aiming at the dependence of load sharing effect, a multistate failure mechanism accumulation model is proposed to sketch it. The multi-state degradation process is modeled for multi-state component and system. In the case study, dynamic reliability of a voltage-stabilizing system with multi-state load sharing effect is evaluated.

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Spectroscopic evidence for Dirac nodal surfaces and nodal rings in the superconductor NaAlSi

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Physical Review B 2022年第16期105卷 L161104-L161104页

作者： Chunyao Song Lei Jin Pengbo Song Hongtao Rong Wenpei Zhu Bo Liang Shengtao Cui Zhe Sun Lin Zhao Youguo Shi Xiaoming Zhang Guodong Liu X. J. Zhou Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology Tianjin 300130 China School of Materials Science and Engineering Hebei University of Technology Tianjin 300130 China National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei 230029 China Songshan Lake Materials Laboratory Dongguan 523808 China Beijing Academy of Quantum Information Sciences Beijing 100193 China

The discovery of the topological states has become a key topic in condensed matter physics with the focus evolving from the Dirac or Weyl points to high-dimensional topological states of the nodal lines and nodal surfaces. For a topological material to manifest its quantum properties and become useful in applications, the topological states need to be genuine and clean so that they lie close to the Fermi level without other trivial bands existing at the Fermi level. While a number of high-dimensional topological materials are predicted, only a few of them have been synthesized and confirmed and the genuine and clean ones are especially scarce. Here, we report the realization of genuine clean multiple high-dimensional topological states in NaAlSi. By performing high-resolution angle-resolved photoemission measurements and band-structure calculations, we have observed two sets of nodal surfaces and the formation of two homocentric nodal ring states in NaAlSi. The observed nodal rings are distinct in that the inner one is a type-I nodal ring while the outer one is a type-I nodal ring embedded with four type-III nodal points. All the bands involved in the nodal rings lie very close to the Fermi level with no other trivial bands coexisting at the Fermi level. These observations make NaAlSi a desirable topological material to explore for novel quantum states and exotic properties.

关键词： Electronic structure Node-line semimetals Topological materials Angle-resolved photoemission spectroscopy

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Spectroscopic Evidence for Dirac Nodal Surfaces and Nodal Rings in Superconductor NaAlSi

arXiv

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arXiv 2023年

作者： Song, Chunyao Jin, Lei Song, Pengbo Rong, Hongtao Zhu, Wenpei Liang, Bo Cui, Shengtao Sun, Zhe Zhao, Lin Shi, Youguo Zhang, Xiaoming Liu, Guodong Zhou, X.J. Beijing National Laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing100190 China University of Chinese Academy of Sciences Beijing100049 China State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology Tianjin300130 China School of Materials Science and Engineering Hebei University of Technology Tianjin300130 China National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei230029 China Beijing Academy of Quantum Information Sciences Beijing100193 China Songshan Lake Materials Laboratory Dongguan523808 China

The discovery of the topological states has become a key topic in condensed matter physics with the focus evolving from the Dirac or Weyl points to high-dimension topological states of the nodal lines and nodal surfaces. For a topological material to manifest its quantum properties and become useful in applications, the topological states need to be genuine and clean so that they lie close to the Fermi level without other trivial bands existing at the Fermi level. While a number of high-dimension topological materials are predicted, only a few of them have been synthesized and confirmed and the genuine and clean ones are especially scarce. Here we report the realization of the genuine clean multiple high-dimension topological states in NaAlSi. By performing high-resolution angle-resolved photoemission measurements and band structure calculations, we have observed two sets of nodal surfaces and the formation of two homocentric nodal ring states in NaAlSi. The observed nodal rings are distinct in that the inner one is a type-I nodal ring while the outer one is a type-I nodal ring embedded with four type-III nodal points. All the bands involved in the nodal rings lie very close to the Fermi level with no other trivial bands coexisting at the Fermi level. These observations make NaAlSi a desirable topological material to explore for novel quantum states and exotic properties. © 2023, CC BY.

关键词： Topology

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Effects of Sic Content on the Microstructure and Properties of the Coatings Prepared by Plasma Spraying Cr2o3-Al-Sic Composite Powder

SSRN

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SSRN 2022年

作者： Ru, Pei-Wen Zhao, Yu-Ping Yang, Yong Shao, Yu-Xuan Wang, Yan-Wei Li, Wei Ma, Yu-Duo Key Lab. for New Type of Functional Materials in Hebei Province School of Materials Science and Engineering State Key Laboratory of Reliability and Intelligence of Electrical Equipment Tianjin Key Laboratory of Materials Laminating Fabrication and Interface Control Technology Hebei University of Technology Tianjin300132 China

Four kinds of chromium carbide composite coatings were successfully prepared on the surface of TC4 titanium alloy by plasma spraying Cr 2 O 3 -Al-SiC system. The effects of SiC content in composite powder on the microstructure and properties of the as-prepared coatings were investigated. The results showed that the desired phases of Cr 7 C 3 , CrSi 2 and Al 2 O 3 were synthesized in situ through the reactions among Cr 2 O 3 , Al and SiC powders. However, due to the different content of each phase in the as-prepared coatings, the microstructure and properties of the coatings were also different. With the increase of SiC content in composite powder, the porosity of the coatings decreased first and then increased, and the microhardness and toughness increased first and then decreased. When the SiC content was 12 wt%, the coating had the lowest porosity, the highest microhardness and the best toughness. This is attributed to the higher reaction degree and better melting state of the composite powder in the plasma jet. The microstructure of the as-prepared coating was uniform and dense, which not only reduced the porosity of the coating, but also improved the microhardness and the toughness of the coating. Therefore, when the content of SiC in Cr 2 O 3 -Al-SiC composite powder is 12 wt%, the coating has the best performance. © 2022, The Authors. All rights reserved.

关键词： Microstructure

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A Novel Predictive Approach to Content Popularity-Aware Edge Caching in VEC

A Novel Predictive Approach to Content Popularity-Aware Edge...

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Software Services engineering (SSE) IEEE International Conference on

作者： YiYuan Zuo Yunni Xia Ruilong Yang Xu Wang Xingli Zhong Qing Xia Xiaoning Sun Jiafeng Feng College of Computer Science Chongqing University Chongqing China College of Mechanical and Vehicle Engineering Chongqing University Chongqing China CISDI Group Co. Ltd Chongqing China Chongqing Key Laboratory of Reliability Technology of Intelligent Electronic appliances Chongqing China School of Computer and Information Science Yunnan Key Laboratory of Service Computing Chongqing Normal University Chongqing China Yunnan University of Finance and Economics Kunming China China Huadian Corporation Guangdong branch Guangdong China

ISBN: (数字)9798350368512

ISBN: (纸本)9798350368529

Mobile edge computing is an emerging computing paradigm boosting resource-demanding and delay-sensitive applications through deploying computing infrastructures at the edge of the Internet nearby mobile requesters and users. In an Internet of Vehicles (IoV) environment, Vehicular Edge Computing (VEC) is capable of exploiting network edge devices, in terms of, e.g., Roadside Units (RSUs), for predictive content caching for optimizing quality-of-experience (QoE) of nearby content requesters based on content popularity analysis, it remains a great challenge to accurately predict content popularity of mobile requesters and appropriately cache required content with low miss rate accordingly in a VEC environment with high user mobility and dynamics. To address this challenge mentioned above, in this paper, we propose predictive content popularity-aware approach, i.e., KM_SVD++, to edge caching in an VEC environment. The proposed approach is capable of achieving high hit rate of mobile content requestors in VEC and low latency of content delivery by leveraging a Kalman filtering model for predicting locations of vehicles and a SVD++ one for yielding decisions for cache deployment and replacement. We conduct extensive simulations as well to prove its effectiveness.

关键词： Multi-access edge computing Software algorithms Predictive models Prediction algorithms Software Kalman filters Quality of experience

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MPS-AMS: MASKED PATCHES SELECTION AND ADAPTIVE MASKING STRATEGY BASED SELF-SUPERVISED MEDICAL IMAGE SEGMENTATION

arXiv

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arXiv 2023年

作者： Wang, Xiangtao Wang, Ruizhi Tian, Biao Zhang, Jiaojiao Zhang, Shuo Chen, Junyang Lukasiewicz, Thomas Xu, Zhenghua State Key Laboratory of Reliability and Intelligence of Electrical Equipment School of Health Sciences and Biomedical Engineering Hebei University of Technology Tianjin China Shenzhen University Shenzhen China Institute of Logic and Computation TU Wien Vienna Austria Department of Computer Science University of Oxford Oxford United Kingdom

Existing self-supervised learning methods based on contrastive learning and masked image modeling have demonstrated impressive performances. However, current masked image modeling methods are mainly utilized in natural images, and their applications in medical images are relatively lacking. Besides, their fixed high masking strategy limits the upper bound of conditional mutual information, and the gradient noise is considerable, making less the learned representation information. Motivated by these limitations, in this paper, we propose masked patches selection and adaptive masking strategy based self-supervised medical image segmentation method, named MPS-AMS. We leverage the masked patches selection strategy to choose masked patches with lesions to obtain more lesion representation information, and the adaptive masking strategy is utilized to help learn more mutual information and improve performance further. Extensive experiments on three public medical image segmentation datasets (BUSI, Hecktor, and Brats2018) show that our proposed method greatly outperforms the state-of-the-art self-supervised baselines. Copyright © 2023, The Authors. All rights reserved.

关键词： Image segmentation

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Cooperated Catalytic Mechanism of Atomically Dispersed Binary Cu-N4 and Zn-N4 in N-Doped Carbon Materials for Promoting Electrocatalytic Co2 Reduction to Ch4

SSRN

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SSRN 2023年

作者： An, Cuihua Wu, Shuai Huang, Rui Chen, Xiaodong Han, Xiaopeng Gomaa, Hassanien Deng, Qibo Zhao, Libin Hu, Ning Key Laboratory of Hebei Province on Scale-span Intelligent Equipment Technology School of Mechanical Engineering Hebei University of Technology Tianjin300401 China Guangdong Provincial Key Laboratory of Electronic Functional Materials and Devices Huizhou University Guangdong Huizhou516001 China Advanced Equipment Research Institute Co. Ltd. Of HEBUT Tianjin300401 China School of Materials Science and Engineering Tianjin University Tianjin300350 China State Key Laboratory of Reliability and Intelligence Electrical Equipment School of Mechanical Engineering Hebei University of Technology Tianjin300401 China Department of Chemistry Faculty of Science Al-Azhar University Assiut71524 Egypt

In order to solve the problems of global climate change and energy crisis, one of the greenest and most efficient methods is the resource utilization of CO2. Among them, electrochemical reduction of CO2 (ERC) to CH4 is one of the most promising solutions. It is imperative to explore catalysts with high activity and stability. Herein, a catalyst composed of atomically dispersed binary Cu-Zn sites on a porous N-doped carbon substrate (CuZn-SAs/NC) is devised to make multi-electron transmission for electro-catalyzing CO2 to CH4 in aqueous media. The Faradaic efficiency (FE) of this catalyst reaches up to 84.7% and a partial current density (at −1.1 V vs. RHE) is about −49.7 mA cm−2, which is superior to single Cu or Zn counterparts. Moreover, after 45 h of ERC, there is no significant attenuation for the current density and FE, suggesting its remarkable stability. Theoretical calculations further indicate that uniformly atomically dispersed Cu-Zn sites and synergistic action of Cu and Zn active centers have substantially impeded CO production and largely accelerated CH4 generation. © 2023, The Authors. All rights reserved.

关键词： Carbon dioxide

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Magnetic Real Chern Insulator in 2D Metal-Organic Frameworks

arXiv

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arXiv 2023年

作者： Zhang, Xiaoming He, Tingli Liu, Ying Dai, Xuefang Liu, Guodong Chen, Cong Wu, Weikang Zhu, Jiaojiao Yang, Shengyuan A. State Key Laboratory of Reliability and Intelligence of Electrical Equipment School of Materials Science and Engineering Hebei University of Technology Tianjin300130 China Department of Physics The University of Hong Kong Hong Kong HKU-UCAS Joint Institute of Theoretical and Computational Physics Hong Kong Shandong University Jinan250061 China Research Laboratory for Quantum Materials Singapore University of Technology and Design Singapore487372 Singapore

Real Chern insulators have attracted great interest, but so far, their material realization is limited to nonmagnetic crystals and to systems without spin-orbit coupling. Here, we reveal magnetic real Chern insulator (MRCI) state in a recently synthesized metal-organic framework material Co3(HITP)2. Its ground state with in-plane ferromagnetic ordering hosts a nontrivial real Chern number, enabled by the C2zT symmetry and robust against spin-orbit coupling. Distinct from previous nonmagnetic examples, the topological corner zero-modes of MRCI are spin-polarized. Furthermore, under small tensile strains, the material undergoes a topological phase transition from MRCI to a magnetic double-Weyl semimetal phase, via a pseudospin-1 critical state. Similar physics can also be found in closely related materials Mn3(HITP)2 and Fe(HITP)2, which are also existing. Possible experimental detections and implications of an emerging magnetic flat band in the system are discussed. Copyright © 2023, The Authors. All rights reserved.

关键词： Topology

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