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Multiple-fold fermions and topological fermi arcs induced catalytic enhancement in nanoporous electride C12A7∶4e−

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arXiv 2021年

作者： Meng, Weizhen Zhang, Xiaoming Liu, Ying Dai, Xuefang Liu, Guodong Kou, Liangzhi 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 School of Mechanical Medical and Process Engineering Queensland University of Technology Garden Point Campus BrisbaneQLD4001 Australia

Topological materials are recently regarded as the idea catalysts due to the protected surface metallic states and high carrier mobility, however the fundamental mechanism and the underlying relationship between the catalytic performance and topological states are in debate. Here, by means of symmetry analysis and first-principles calculations, we discover that the electride material of C12A7:4e− hosts the multiple-fold fermions due to the interstitial-electrons, with the sixfold- and fourfold- degenerate points locating at high symmetric points near the Fermi energy, which are identified as the underlying reason of the enhanced catalytic ability in C12A7:4e−-based catalysts. The multiple-fold fermions exhibit much longer Fermi arcs on the (001) surface than traditional Weyl/Dirac fermions, the surface is thus highly chemical active and possesses a low Gibbs free energy (∆GH* = 0.24 eV) for the hydrogen evolution reaction. The underlying relationship between catalytic performance and the topological surface state is explicitly verified by artificially hole doping, external strain and similar electride without the Fermi arcs, where the Gibbs free energies are significantly increased when the Fermi arcs is shifted to higher energy level. This work offers a guiding principle for understanding catalytic nature of electrides and the topological quantum catalysts. © 2021, CC0.

关键词： Catalysts

Observation of spin-polarized surface states in a nodal line semimetal SnTaS2

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arXiv 2023年

作者： Song, Chunyao Liu, Lulu Cui, Shengtao Gao, Jingjing Song, Pengbo Jin, Lei Zhao, Wenjuan Sun, Zhe Zhang, Xiaoming Zhao, Lin Luo, Xuan Sun, Yuping Shi, Youguo Zhang, Haijun 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 National Laboratory of Solid State Microstructures School of Physics Nanjing University Nanjing210093 China National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei230029 China Key Laboratory of Materials Physics Institute of Solid State Physics HFIPS Chinese Academy of Sciences Hefei230031 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 Elettra Sincrotrone Trieste Trieste34149 Italy Songshan Lake Materials Laboratory Dongguan523808 China Collaborative Innovation Center of Advanced Microstructures Nanjing University Nanjing210093 China High Magnetic Field Laboratory HFIPS Chinese Academy of Sciences Hefei230031 China Beijing Academy of Quantum Information Sciences Beijing100193 China

The superconductor SnTaS2 is theoretically predicted to be an intriguing topological nodal line semimetal without consideration of spin-orbit coupling. By carrying out angle-resolved photoemission (ARPES) and spin-resolved ARPES measurements combined with band structure calculations, we have provided a complete picture of the electronic structure and spin polarization property for the prominent surface states of SnTaS2. The low-energy electronic states are dominated by surface states;two of them are from the S-terminated surface, while four of them are from the Sn-terminated surface. These give rise to interesting Fermi surface topology of SnTaS2: three pockets located at Γ, ¯ M¯ and K¯ for the S-terminated surface and two pockets surrounding Γ¯ and K¯ for the Sn-terminated surface. We further reveal that two surface states that cross the Fermi level are spin-polarized. Since SnTaS2 is also a superconductor, our observations indicate that it may provide a new platform to explore topological superconductivity and other exotic properties. © 2023, CC BY.

关键词： Tin compounds

Cryogenic Characterization of Nano-scale Bulk FinFETs 15

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Cryogenic Characterization of Nano-scale Bulk FinFETs

15th IEEE International Conference on Solid-State and Integrated Circuit technology, ICSICT 2020

作者： Fan, Lin-Jie Bi, Jin-Shun Fan, Xue Xu, Gao-Bo Xu, Yan-Nan Xi, Kai Zhang, Zhan-Gang Institute of Microelectronics Chinese Academy of Sciences Beijing100029 China University of Chinese Academy of Sciences Beijing100049 China School of Electrical Engineering Chengdu Technological University Chengdu611730 China Science and Technology on Reliability Physics and Application of Electronic Component Laboratory China Electronic Product Reliability and Environmental Testing Research Institute Guangzhou510610 China

ISBN: (纸本)9781728162355

For the state-of-Art quantum technology applications, the effective control and high-speed reading of a large number of qubits require a combination of complementary metal-oxide-semiconductor (CMOS) circuits in cryogenic temperatures environments. In this letter, the electrical responses of bulk fin field effect transistor (FinFET) devices that could be applied in quantum controllers have been investigated under cryogenic conditions. The devices under test are high-k metal gate bulk FinFETs with 35 nm channel length. The electrical properties of the FinFET device are greatly optimized at cryogenic temperatures. As the temperature decreases, the FinFET exhibits a larger saturation current, smaller subthreshold swing, larger maximum transconductance, and smaller gate-induced drain leakage current. These results provide experimental evidence for the implementation of the FinFET in control systems for quantum chips in cryogenic environments. © 2020 IEEE.

关键词： Cryogenics

EFSM Test Data Generation Based on Fault Propagation and Multi-Population Genetic Algorithm

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EFSM Test Data Generation Based on Fault Propagation and Mul...

International Conference on Dependable Systems and Their Applications (DSA)

作者： Zhiqin Cao Yichen Wang Peng Guo Bo Tian School of Reliability and Systems engineering Beihang University Beijing China Science and Technology on Reliability and Environental Engineering Laboratory Beihang University Beijing China Industry Computing Institute Beijing China

ISBN: (数字)9780738124223

ISBN: (纸本)9781665419536

EFSM is widely used in the modeling of control systems and protocols. Genetic algorithm is often used in EFSM test data generation due to its good performance. However, genetic algorithm tends to converge prematurely in complex search space and fall into local optimum, which leads to poor search efficiency. At the same time, test cases generated by genetic algorithm for EFSM have the problem of poor defect detection ability. Aiming at the above two problems, we improve genetic algorithm based on fault propagation assumption and multi-population strategy, design and implement the multi-population genetic algorithm based on fault propagation. In order to verify the performance of the improved algorithm, we design and conduct a control experiment, the results of the experiment show that the algorithm we proposed can effectively solve the problem of falling into local optimum and has advantages in defect detection.

关键词： Protocols Aerospace electronics Control systems Genetic algorithms

Geometrically Nonlinear Random Responses of Stiffened Plates Under Acoustic Pressure

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Transactions of Nanjing University of Aeronautics and Astronautics 2020年第5期37卷 726-738页

作者： YANG Shaochong LI Youchen YANG Qingsheng WANG Jianmin College of Civil Engineering and Architecture Hebei UniversityBaoding 071002P.R.China Department of Engineering Mechanics Beijing University of TechnologyBeijing 100124P.R.China Science and Technology on Reliability and Environment Engineering Laboratory Beijing Institute of Structure and Environment EngineeringBeijing 100076P.R.China

An algorithm integrating reduced order model(ROM),equivalent linearization(EL),and finite element method(FEM)is proposed to carry out geometrically nonlinear random vibration analysis of stiffened plates under acoustic pressure *** on large deflection finite element formulation,the nonlinear equations of motion of stiffened plates are *** reduce the computation,a reduced order model of the structures is *** the EL technique is incorporated into FE software NASTRAN by the direct matrix abstraction program(DMAP).For the stiffened plates,a finite element model of beam and plate assembly is established,in which the nodes of beam elements are shared with shell elements,and the offset and section properties of the beam are *** presented method can capture the root-mean-square(RMS) of the stress responses of shell and beam elements of stiffened plates,and analyze the stress distribution of the stiffened surface and the unstiffened surface,***,the statistical dynamic response results obtained by linear and EL methods are *** is shown that the proposed method can be used to analyze the geometrically nonlinear random responses of stiffened *** geometric nonlinearity plays an important role in the vibration response of stiffened plates,particularly at high acoustic pressure loading.

关键词： stiffened plate acoustic loading geometric nonlinearity random vibration equivalent linearization

An Empirical study of Exploring Relevant Metrics to Assess Software Product Quality

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An Empirical study of Exploring Relevant Metrics to Assess S...

International Conference on Dependable Systems and Their Applications (DSA)

作者： Zekun Song Yichen Wang Wentao Wang Jing Zhang Science & Technology on Reliability & Environment Engineering Laboratory Beihang University Beijing China CETC29 Chengdu China

ISBN: (数字)9780738124223

ISBN: (纸本)9781665419536

This paper proposes an empirical study of exploring relevant and operable metrics to assess software product quality based on quality characteristics of ISO/IEC 25010. Both data-driven and Goal-Question-Metric approach are applied to excavate as many full-life-cycle metrics as possible. Goal-Question-Metric approach is applied to identify software metrics affecting product quality in a specific domain. Machine learning algorithm that support incremental training is applied to learn the relationship between code metrics and quality characteristic marks from historical data. Thus full-life-cycle software metrics are identified and we build a software quality assessment model based on historical code metric *** case studies are conducted based on actual projects from the past 2 years to verify the feasibility of methodology, including an empirical investigation of mostly concerned quality factors in an electronic equipment software institute, a collection of code metrics and quality characteristic marks of 82 aviation embedded software projects, as well as a comparation of the performance of logistic regression, k-Nearest Neighbor and BP neural network algorithm for quality assessment. Those cases are performed with actual data in actual institutes and projects. Additionally, a support tool for project data management and quality assessment is *** feedback from cooperative engineers, we still see room for improvements to fill the gap between methodology and actual software engineering process. Nevertheless, the empirical validation shows the feasibility of the metrics for quality assessment.

关键词： Measurement Training Software metrics Software quality Tools Product design Quality assessment

Scaling of variations in traveling distances and times of taxi routes

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arXiv 2021年

作者： Feng, Xiaoyan Sun, Huijun Gross, Bnaya Wu, Jianjun Li, Daqing Yang, Xin Zhou, Dong Gao, Ziyou Havlin, Shlomo School of Traffic and Transportation Beijing Jiaotong University Beijing100044 China Department of Physics Bar-Ilan University Ramat-Gan52900 Israel State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong University Beijing100044 China School of Reliability and Systems Engineering Beihang University Beijing100191 China National Key Laboratory of Science and Technology on Reliability and Environmental Engineering Beijing100191 China

The importance of understanding human mobility patterns has led many studies to examine their spatial-temporal scaling laws. These studies mainly reveal that human travel can be highly non-homogeneous with power-law scaling distributions of distances and times. However, investigating and quantifying the extent of variability in time and space when traveling the same air distance has not been addressed so far. Using taxi data from five large cities, we focus on several novel measures of distance and time to explore the spatio-temporal variations of taxi travel routes relative to their typical routes during peak and nonpeak periods. To compare all trips using a single measure, we calculate the distributions of the ratios between actual travel distances and the average travel distance as well as between actual travel times and the average travel time for all origin destinations (OD) during peak and nonpeak periods. In this way, we measure the scaling of the distribution of all single trip paths with respect to their mean trip path. Our results surprisingly demonstrate very broad distributions for both the distance ratio and time ratio, characterized by a long-tail power-law distribution. Moreover, all analyzed cities have larger exponents in peak hours than in nonpeak hours. We suggest that the interesting results of shorter trip lengths and times, characterized by larger exponents during rush hours, are due to the higher availability of travelers in rush hours compared to non-rush hours. We also find a high correlation between distances and times, and the correlation is lower during peak hours than during nonpeak hours. The reduced correlations can be understood as follows. Due to the high availability of passengers in peak periods more drivers choose long distances to save time compared to nonpeak periods. Furthermore, we employed an indeterminate traffic assignment model, which supports our finding of the power-law distribution of the distance ratio and time ratio f

关键词： Taxicabs

Deep Forest with Hashing Screening and Window Screening

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arXiv 2022年

作者： Ma, Pengfei Wu, Youxi Li, Yan Guo, Lei Jiang, He Zhu, Xingquan Wu, Xindong School of Artificial Intelligence Hebei University of Technology Tianjing300401 China Hebei Key Laboratory of Big Data Computing Tianjing300401 China School of Economics and Management Hebei University of Technology Tianjing300401 China State Key Laboratory of Reliability and Intelligence of Electrical Equipment Hebei University of Technology Tianjing300401 China School of Software Dalian University of Technology Dalian116023 China Department of Computer & Electrical Engineering and Computer Science Florida Atlantic University FL33431 United States Hefei University of Technology Hefei230009 China Mininglamp Academy of Sciences Mininglamp Technology Beijing100084 China

As a novel deep learning model, gcForest has been widely used in various applications. However, the current multi-grained scanning of gcForest produces many redundant feature vectors, and this increases the time cost of the model. To screen out redundant feature vectors, we introduce a hashing screening mechanism for multi-grained scanning and propose a model called HW-Forest which adopts two strategies, hashing screening and window screening. HW-Forest employs perceptual hashing algorithm to calculate the similarity between feature vectors in hashing screening strategy, which is used to remove the redundant feature vectors produced by multi-grained scanning and can significantly decrease the time cost and memory consumption. Furthermore, we adopt a self-adaptive instance screening strategy to improve the performance of our approach, called window screening, which can achieve higher accuracy without hyperparameter tuning on different datasets. Our experimental results show that HW-Forest has higher accuracy than other models, and the time cost is also reduced. Copyright © 2022, The Authors. All rights reserved.

关键词： Scanning

High-performance fiber-integrated multifunctional graphene-optoelectronic device with photoelectric detection and optic-phase modulation

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Photonics Research 2020年第12期8卷 1949-1957页

作者： LINQING ZHUO PENGPENG FAN SHUANG ZHANG YUANSONG ZHAN YANMEI LINYU ZHANG DONGQUAN LI ZHEN CHE WENGUO ZHU HUADAN ZHENG JIEYUAN TANG JUN ZHANG YONGCHUN ZHONG WENXIAO FANG GUOGUANG LU JIANHUI YU ZHE CHEN Key Laboratory of Optoelectronic Information and Sensing Technologies of Guangdong Higher Education Institutes Department of Optoelectronic EngineeringJinan UniversityGuangzhou 510632China Engineering Research Center on Visible Light Communication of Guangdong Province Department of Optoelectronic EngineeringJinan UniversityGuangzhou 510632China Key Laboratory of Visible Light Communications of Guangzhou Jinan UniversityGuangzhou 510632China Science and Technology on Reliability Physics and Application of Electronic Component Laboratory China Electronic Product Reliability and Environmental Testing Research InstituteGuangzhou 510610China

In graphene-based optoelectronic devices,the ultraweak interaction between a light and monolayer graphene leads to low optical absorption and low responsivity for the photodetectors and relative high half-wave voltage for the phase ***,an integration of the monolayer graphene onto the side-polished optical fiber is demonstrated,which is capable of providing a cost-effective strategy to enhance the light–graphene interaction,allowing us to obtain a highly efficient optical absorption in graphene and achieve multifunctions:photodetection and optical phase *** a photodetector,the device has ultrahigh responsivity(1.5×10^(7) A/W)and high external quantum efficiency(>1.2×10^(9)%).Additionally,the polybutadiene/polymethyl methacrylate(PMMA)film on the graphene can render the device an optical phase modulator through the large thermo-optic effect of the *** a phase modulator,the device has a relatively low half-wave voltage of 3 V with a 16 dB extinction ratio in Mach–Zehnder interferometer configuration.

关键词： optoelectronic fiber modulator