检索结果-内蒙古大学图书馆

Evidence of gate-tunable mott insulator in trilayer graphene-boron nitride moiré superlattice

学校读者我要写书评

暂无评论

arXiv 2018年

作者： Chen, Guorui Jiang, Lili Wu, Shuang Lv, Bosai Li, Hongyuan Chittari, Bheema Lingam Watanabe, Kenji Takashi Taniguchi Shi, Zhiwen Jung, Jeil Zhang, Yuanbo Wang, Feng Department of Physics University of California at Berkeley BerkeleyCA United States State Key Laboratory of Surface Physics Department of Physics Fudan University Shanghai200433 China Materials Science Division Lawrence Berkeley National Laboratory BerkeleyCA United States Key Laboratory of Artificial Structures and Quantum Control Ministry of Education School of Physics and Astronomy Shanghai Jiao Tong University Shanghai China Department of Electrical Engineering and Computer Sciences University of California BerkeleyCA94720 United States Collaborative Innovation Center of Advanced Microstructures Nanjing China National Institute for Materials Science 1-1 Namiki Tsukuba305-0044 Japan Department of Physics University of Seoul Seoul02504 Korea Republic of Institute for Nanoelectronic Devices and Quantum Computing Fudan University Shanghai200433 China Kavli Energy NanoSciences Institute University of California Berkeley Lawrence Berkeley National Laboratory BerkeleyCA United States

Mott insulator plays a central role in strongly correlated physics, where the repulsive Coulomb interaction dominates over the electron kinetic energy and leads to insulating states with one electron occupying each unit cell.1,2 Doped Mott insulator is often described by the Hubbard model3, which can give rise to other correlated phenomena such as unusual magnetism and even high temperature superconductivity2,4. A tunable Mott insulator, where the competition between the Coulomb interaction and the kinetic energy can be varied in situ, can provide an invaluable model system for the study of Mott physics. Here we report the realization of such a tunable Mott insulator in the ABC trilayer graphene (TLG) and hexagonal boron nitride (hBN) heterostructure with a moiré superlattice. Unlike massless Dirac electrons in monolayer graphene5,6, electrons in pristine ABC TLG are characterized by quartic energy dispersion and large effective mass7-11 that are conducive for strongly correlated phenomena. The moiré superlattice12-18 in TLG/hBN heterostructures leads to narrow electronic minibands that are gatetunable. Each filled miniband contains 4 electrons in one moiré lattice site due to the spin and valley degeneracy of graphene. The Mott insulator states emerge at 1/4 and 1/2 fillings, corresponding to one electron and two electrons per site, respectively. Moreover, the Mott states in the ABC TLG/hBN heterostructure exhibit unprecedented tunability: The Mott gap can be modulated in situ by a vertical electrical field, and at the mean time the electron doping can be gate-tuned to fill the band from one Mott insulating state to another. Our observation of a tunable Mott insulator opens up exciting opportunities to explore novel strongly correlated phenomena in two-dimensional moiré superlattice heterostructures. Copyright © 2018, The Authors. All rights reserved.

关键词： Mott insulators

A tensor-based framework for studying eigenvector multicentrality in multilayer networks

学校读者我要写书评

暂无评论

arXiv 2017年

作者： Wu, Mincheng He, Shibo Zhang, Yongtao Chen, Jiming Sun, Youxian Liu, Yang-Yu Zhang, Junshan Vincent Poor, H. State Key Laboratory of Industrial Control Technology Zhejiang University Hangzhou Zhejiang310027 China Channing Division of Network Medicine Brigham and Women's Hospital Harvard Medical School BostonMA02115 United States Center for Cancer Systems Biology Dana-Farber Cancer Institute BostonMA02115 United States School of Electrical Computer and Energy Engineering Arizona State University TempeAZ85287 United States Department of Electrical Engineering Princeton University PrincetonNJ08544 United States

Centrality is widely recognized as one of the most critical measures to provide insight in the structure and function of complex networks. While various centrality measures have been proposed for single-layer networks, a general framework for studying centrality in multilayer networks (i.e., multicentrality) is still lacking. In this study, a tensor-based framework is introduced to study eigenvector multicentrality, which enables the quantification of the impact of interlayer influence on multicentrality, providing a systematic way to describe how multicentrality propagates across different layers. This framework can leverage prior knowledge about the interplay among layers to better characterize multicentrality for varying scenarios. Two interesting cases are presented to illustrate how to model multilayer influence by choosing appropriate functions of interlayer influence and design algorithms to calculate eigenvector multicentrality. This framework is applied to analyze several empirical multilayer networks, and the results corroborate that it can quantify the influence among layers and multicentrality of nodes effectively. Copyright © 2017, The Authors. All rights reserved.

关键词： Eigenvalues and eigenfunctions

Improvement of Resting-state EEG Analysis Process with Spectrum Weight-Voting based on LES

学校读者我要写书评

暂无评论

arXiv 2017年

作者： Ye, Yumeng Liu, Haichun Zhang, TianHong Pan, Changchun Yang, Genke Wang, JiJun Qiu, Robert C. Key Laboratory of System Control and Information Processing Shanghai Jiaotong University Ministry of Education of China Shanghai200240 China Department of Automation and Shanghai Key Laboratory of Navigation and Location Based Services Shanghai Key Laboratory of Psychotic Disorders Shanghai Mental Health Center Shanghai Jiaotong University School of Medicine Shanghai200030 China Brain Science and Technology Research Center Shanghai Jiao Tong University Shanghai200240 China Shanghai Jiaotong University Shanghai200240 China Department of Electrical Engineering Shanghai Jiaotong University Shanghai200240 China Department of Electrical and Computer Engineering Tennessee Technological University CookevilleTN38505 United States

Electroencephalography is a non-invasive technique for recording brain bioelectric activity, which has potential applications in various fields such as human-computer interaction and neuroscience. Among them, analysis of the risk of schizophrenia using EEG data is a relatively new research topic. However, there are many difficulties in analyzing EEG data, including its complex composition, low amplitude as well as low signal-to-noise ratio. Some of the existing methods of analysis are based on feature extraction and machine learning to differentiate the phase of schizophrenia (First-episode schizophrenia, Healthy controls or Clinical high-risk) that samples belong to. However, medical research requires the use of machine learning not only to give more accurate classification results, but also to give the results that can be applied to pathological studies. The main purpose of this study is to obtain the weight values as the representation of influence of each frequency band on the classification of schizophrenia phases on the basis of a more effective classification method using the LES feature extraction, and then the weight values are processed and applied to improve the accuracy of machine learning classification. We propose a method called weight-voting to obtain the weights of sub-bands features by using results of classification for voting to fit the actual categories of EEG data, and using weights for reclassification. Through this method, we can first obtain the influence of each band in distinguishing three schizophrenia phases, and analyze the effect of band features on the risk of schizophrenia contributing to the study of psychopathology. In addition, the weights applied to the original classifier can achieve the upgrade of the classification effect, which contributes to the BCI-assisted system of diagnosis and treatment. Our results show that there is a high correlation between the change of weight of low gamma band and the difference between HC, CHR an

关键词： Electroencephalography

Spatial frequency modulated imaging (SPIFI) in amplitude with a spatial light modulator

学校读者我要写书评

暂无评论

Spatial frequency modulated imaging (SPIFI) in amplitude wit...

Frontiers in Optics, FiO 2016

作者： Young, Michael D. Field, Jeffrey J. Bartels, Randy A. Squier, Jeff Center for Microintegrated Optics for Advanced Biological Control Department of Physics Colorado School of Mines 1500 Illinois Street GoldenCO80401 United States Department of Electrical and Computer Engineering Colorado State University 200 West Lake Street Fort CollinsCO80523 United States

Previous work has demonstrated modulated imaging with binary masks. We present a new microscope that provides continuous modulation with a spatial light modulator, which can modulate through multiple methods: amplitud... 详细信息

ISBN: (纸本)9781943580194

关键词： Light modulators

Aperiodic Multilayer Graphene Based Tunable and Switchable Thermal Emitter at Mid-Infrared Frequencies

学校读者我要写书评

暂无评论

ECS Meeting Abstracts 2017年第29期MA2017-01卷

作者： Safura Sharifi Yaser Mohammadi Banadaki Chenglong You Simon Lorenzo Georgios Veronis Jonathan P. Dowling Center for Computation and Technology School of Electrical Engineering & Computer Science LSU Southern University and A&M College - Baton Rouge Hearne Institute for Theoretical Physics LSU Hearne Institute for Theoretical Physics Department of Physics and Astronomy LSU School of Electrical Engineering & Computer Science LSU

Graphene has attracted an explosion of interest for photonic applications as it provides a degree of freedom to manipulate electromagnetic waves. In this work, we propose a new one-dimensional system composed of multiple graphene and hexagonal boron nitride (hBN) with varying aperiodic thicknesses in between the graphene layers. A hybrid optimization method, consisting of a micro-genetic global optimization algorithm coupled to a local optimization algorithm, indicates that absorption efficiency close to 100% can be achieved at very narrow frequency range under normal incidence. This efficiency can be significantly decreased by tuning the chemical potential and the corresponding carrier density in graphene. It thus enables a promising way to design electrically controllable thermal emitter. Fig. 1(a) shows the proposed device structure composed of 23 graphene layers and 22 alternating layers of hexagonal boron nitride (hBN) insulator, which sandwiches between two thick silicon carbide (SiC) layers. The hBN has two-dimensional atomic structure similar to graphene and has been proposed as its promising complementary insulator layer. The ambient temperature of 873 K is assumed, in which the semi-infinite tungsten substrate creates the thermal emission of black body radiation with maximum emission at infrared range. Since the tungsten substrate is taken to be semi-infinite, the transmittance is identically zero (Absorption = 1-Reflection) and the calculated absorption can be equated to emittance because of Kirchhoff's second law and conservation of energy. The Kubo formula is used to extract the optical conductivity and consequently the refractive index of graphene while the experimental data is used for the wavelength-dependent indices of refraction of other materials. Fig. 1(b) shows the normalized power radiated per unit area and unit wavelength by the structure. In order to find the optimized structure with narrowband thermal emittance, the chemical potential initia

关键词：

Vibration isolation system with a compact damping system for power recycling mirrors of KAGRA

学校读者我要写书评

暂无评论

arXiv 2019年

作者： Akiyama, Y. Akutsu, T. Ando, M. Arai, K. Arai, Y. Araki, S. Araya, A. Aritomi, N. Asada, H. Aso, Y. Bae, S. Baiotti, L. Barton, M.A. Cannon, K. Capocasa, E. Chen, C.-S. Chiu, T.-W. Cho, K. Chu, Y.-K. Craig, K. Dattilo, V. Doi, K. Enomoto, Y. Flaminio, R. Fujii, Y. Fujimoto, M.-K. Fukunaga, M. Fukushima, M. Furuhata, T. Haino, S. Hasegawa, K. Hashimoto, Y. Hashino, K. Hayama, K. Hirayama, T. Hirose, E. Hsieh, B.H. Huang, C.-Z. Ikenoue, B. Inoue, Y. Ioka, K. Itoh, Y. Izumi, K. Kaji, T. Kajita, T. Kakizaki, M. Kamiizumi, M. Kanbara, S. Kanda, N. Kanemura, S. Kang, G. Kasuya, J. Kawai, N. Kawasaki, T. Kim, C. Kim, W.S. Kim, J. Kim, J.C. Kimura, N. Kirii, S. Kitaoka, Y. Kitazawa, H. Kojima, Y. Kokeyama, K. Komori, K. Kong, A. Kotake, K. Kozu, R. Kumar, R. Kuo, H.-S. Kuroki, S. Kuroyanagi, S. Lee, H.K. Lee, H.M. Lee, H.W. Leonardi, M. Lin, C.-Y. Lin, F.-L. Liu, G.C. Marchio, M. Matsui, T. Michimura, Y. Mio, N. Miyakawa, O. Miyamoto, A. Miyoki, S. Morii, W. Morisaki, S. Moriwaki, Y. Musha, M. Nagano, S. Nagano, K. Nakamura, K. Nakamura, T. Nakano, H. Nakano, M. Narikawa, T. Quynh, L. Nguyen Ni, W.-T. Nishizawa, A. Obuchi, Y. Oh, J. Oh, S.H. Ohashi, M. Ohishi, N. Ohkawa, M. Okutomi, K. Ono, K. Oohara, K. Ooi, C.P. Pan, S.-S. Paoletti, F. Park, J. Passaquieti, R. Peña Arellano, F.E. Sago, N. Saito, S. Saito, Y. Sakai, K. Sakai, Y. Sasai, M. Sato, S. Sato, T. Sekiguchi, T. Sekiguchi, Y. Shibata, M. Shimoda, T. Shinkai, H. Shishido, T. Shoda, A. Someya, N. Somiya, K. Son, E.J. Suemasa, A. Suzuki, T. Suzuki, T. Tagoshi, H. Tahara, H. Takahashi, H. Takahashi, R. Takeda, H. Tanaka, H. Tanaka, K. Tanaka, T. Tanioka, S. San Martin, E.N. Tapia Tomaru, T. Tomura, T. Travasso, F. Tsubono, K. Tsuchida, S. Uchikata, N. Uchiyama, T. Uehara, T. Ueno, K. Uraguchi, F. Ushiba, T. van Putten, M.H.P.M. Vocca, H. Wakamatsu, T. Watanabe, Y. Xu, W.-R. Yamada, T. Yamamoto, K. Yamamoto, K. Yamamoto, S. Yamamoto, T. Yokogawa, K. Yokoyama, J. Yokozawa, T. Yoshioka, T. Yuzurihara, H. Zeidler, S. Zhu, Z.-H. Graduate School of Science and Engineering Hosei University TokyoKoganei184-8584 Japan National Astronomical Observatory of Japan TokyoMitaka181-8588 Japan Department of Physics University of Tokyo TokyoBunkyo113-0033 Japan University of Tokyo KashiwaChiba277-8582 Japan High Energy Accelerator Research Organization TsukubaIbaraki305-0801 Japan Earthquake Research Institute University of Tokyo TokyoBunkyo113-0032 Japan Department of Physics University of Tokyo TokyoBunkyo113-0033 Japan Department of Mathematics and Physics Hirosaki University AomoriHirosaki036-8561 Japan National Astronomical Observatory of Japan GifuHida506-1205 Japan Korea Institute of Science and Technology Information Yuseong Daejeon34141 Korea Republic of Department of Physics Osaka University ToyonakaOsaka560-0043 Japan University of Tokyo TokyoBunkyo113-0033 Japan Department of Physics National Taiwan Normal University Taipei116 Taiwan Department of Physics Sogang University Seoul121-742 Korea Republic of PisaCascinaI-56021 Italy Department of Physics University of Toyama ToyamaToyama930-8555 Japan Department of Astronomy University of Tokyo TokyoBunkyo113-0032 Japan Advanced Technology Center National Astronomical Observatory of Japan TokyoMitaka181-8588 Japan Institute of Physics Academia Sinica TaipeiNankang11529 Taiwan Department of Applied Physics Fukuoka University FukuokaJonan814-0180 Japan Yukawa Institute for Theoretical Physics Kyoto University KyotoSakyo606-8502 Japan Graduate School of Science Osaka City University OsakaSumiyosi558-8585 Japan Institute of Space and Astronautical Science Japan Aerospace Exploration Agency SagamiharaKanagawa252-5210 Japan University of Tokyo GifuHida506-1205 Japan Graduate Schoool of Science and Technology Tokyo Institute of Technology MeguroTokyo152-8551 Japan Department of Physics Ewha Womans University SeoulSeodaemun-gu03760 Korea Republic of National Institute for

A vibration isolation system called Type-Bp system used for power recycling mirrors has been developed for KAGRA, the interferometric gravitational-wave observatory in Japan. A suspension of the Type-Bp system passively isolates an optic from seismic vibration using three main pendulum stages equipped with two vertical vibration isolation systems. A compact reaction mass around each of the main stages allows for achieving sufficient damping performance with a simple feedback as well as vibration isolation ratio. Three Type-Bp systems were installed in KAGRA, and were proved to satisfy the requirements on the damping performance, and also on estimated residual displacement of the optics. Copyright © 2019, The Authors. All rights reserved.

关键词： Mirrors

controlling the magnetic anisotropy in epitaxial Y3Fe5O12 films by manganese doping

学校读者我要写书评

暂无评论

Physical Review B 2017年第22期96卷 224403-224403页

作者： C. T. Wang X. F. Liang Y. Zhang X. Liang Y. P. Zhu J. Qin Y. Gao B. Peng N. X. Sun L. Bi National Engineering Research Center of Electromagnetic Radiation Control Materials University of Electronic Science and Technology of China Chengdu 610054 China State Key Laboratory of Electronic Thin Films and Integrated Devices University of Electronic Science and Technology of China Chengdu 610054 China Key Laboratory of Multi-spectral Absorbing Materials and Structures of Ministry of Education University of Electronic Science and Technology of China Chengdu 610054 China Department of Electrical and Computer Engineering Northeastern University 360 Huntington Avenue Boston Massachusetts 02115 USA Winchester Technologies LLC Burlington Massachusetts 01803 USA

controlling the magnetic anisotropy in epitaxial Y3Fe5O12 (YIG) thin films is critical for magnonic and photonic device applications. In this paper, we report the crystal structure, magnetic properties, and magnetic anisotropy of epitaxial Y3(Fe5−xMnx)O12 (Mn:YIG) thin films grown on Gd3Ga5O12 (111) (GGG) substrates by pulsed-laser deposition. Mn doping is observed to strongly enhance the magnetoelastic coefficient of YIG thin films, which leads to large tunability of the thin film magnetic anisotropy by lattice strain. With increasing Mn concentration from x=0 to x=1.25, a continuous increase of out-of-plane magnetic anisotropy ranging from −644.4 Oe to 1337.5 Oe is observed. In particular, a perpendicular magnetic anisotropy (PMA) is achieved in Mn:YIG thin films with a high Mn concentration of x=1.12. Ferromagnetic resonance (FMR) measurements show low FMR linewidths of 3.4 Oe to 129 Oe at 9.5 GHz in Mn:YIG thin films. Our paper demonstrates manganese doping as an effective way to enhance the magnetoelastic anisotropy of YIG thin films by strain, which is useful for magnonic and magneto-optical device applications.

关键词： Jahn-Teller effect Magnetic anisotropy Magnetoelastic effect Spintronics

Adaptive optimization for active queue management supporting TCP flows

学校读者我要写书评

暂无评论

Adaptive optimization for active queue management supporting...

American control Conference

作者： Simone Baldi Elias B. Kosmatopoulos Andreas Pitsillides Marios Lestas Petros A. Ioannou Yiming Wan Delft Center of Systems and Control Netherlands Dept. of Electrical and Computer Engineering Democritus University of Thrace Xanthi Greece Computer Science Department University of Cyprus (UCY) Nicosia Cyprus Department of Electrical Engineering Frederick University Nicosia Cyprus Department of Electrical Engineering University of Southern California Los Angeles USA

ISBN: (纸本)9781467386838

An adaptive decentralized strategy for active queue management of TCP flows over communication networks is presented. The proposed strategy solves locally, at each link, an optimal control problem, minimizing a cost composed of residual capacity and buffer queue size. The solution of the optimal control problem exploits an adaptive optimization algorithm aiming at adaptively minimizing a suitable approximation of the Hamilton-Jacobi-Bellman equation associated with the optimal control problem. Simulations results, obtained by using a fluid flow based model of the communication network and a common network topology, show improvement with respect to the Random Early Detection strategy. Besides, it is shown that the performance of the proposed decentralized solution is comparable with the performance obtained with a centralized strategy, which solves the optimal control problem via a central unit that maintains the flow states of the entire network.

关键词： Protocols Communication networks Optimal control Mathematical model Delays Optimization networks(communications) Optimal control rotation management adaptive optimization protocols Mathematical Model Telecommunications Tritolyl Phosphates tactical command post Network topology delay Residual Volume fluid flow

Optimized mid-infrared thermal emitters for applications in aircraft countermeasures

学校读者我要写书评

暂无评论

Optimized mid-infrared thermal emitters for applications in ...

Frontiers in Optics, FiO 2016

作者： Lorenzo, Simón G. You, Chenglong Granier, Christopher H. Veronis, Georgios Dowling, Jonathan P. Hearne Institute for Theoretical Physics and Department of Physics and Astronomy Louisiana State University Baton RougeLA70803 United States School of Electrical Engineering and Computer Science Louisiana State University Baton RougeLA70803 United States Center for Computation and Technology Louisiana State University Baton RougeLA70803 United States

An optimized aperiodic photonic crystal structure is capable of near-blackbody and broad angle thermal emission at aircraft engine temperatures over the three to five mm atmospheric transmission band. © OSA 2016.

ISBN: (纸本)9781943580194

关键词： Aircraft engines