检索结果-内蒙古大学图书馆

Topological Insulators in Twisted Transition Metal Dichalcogenide Homobilayers

Physical Review Letters 2019年第8期122卷 086402-086402页

作者： Fengcheng Wu Timothy Lovorn Emanuel Tutuc Ivar Martin A. H. MacDonald Materials Science Division Argonne National Laboratory Argonne Illinois 60439 USA Condensed Matter Theory Center and Joint Quantum Institute Department of Physics University of Maryland College Park Maryland 20742 USA Department of Physics University of Texas at Austin Austin Texas 78712 USA Department of Electrical and Computer Engineering Microelectronics Research Center The University of Texas at Austin Austin Texas 78758 USA

We show that moiré bands of twisted homobilayers can be topologically nontrivial, and illustrate the tendency by studying valence band states in ±K valleys of twisted bilayer transition metal dichalcogenides, in particular, bilayer MoTe2. Because of the large spin-orbit splitting at the monolayer valence band maxima, the low energy valence states of the twisted bilayer MoTe2 at the +K (−K) valley can be described using a two-band model with a layer-pseudospin magnetic field Δ(r) that has the moiré period. We show that Δ(r) has a topologically nontrivial skyrmion lattice texture in real space, and that the topmost moiré valence bands provide a realization of the Kane-Mele quantum spin-Hall model, i.e., the two-dimensional time-reversal-invariant topological insulator. Because the bands narrow at small twist angles, a rich set of broken symmetry insulating states can occur at integer numbers of electrons per moiré cell.

关键词： Electronic structure Kane-Mele model Quantum spin Hall effect Topological insulators Transition metal dichalcogenides Two-dimensional electron system

来源：评论

学校读者我要写书评

暂无评论

SUCAG: Stochastic unbiased curvature-aided gradient method for distributed optimization

arXiv

引用

arXiv 2018年

作者： Wai, Hoi-To Freris, Nikolaos M. Nedić, Angelia Scaglione, Anna School of Electrical Computer and Energy Engineering Arizona State University TempeAZ85281 United States Division of Engineering New York University Abu Dhabi NYU Tandon School of Engineering

We propose and analyze a new stochastic gradient method, which we call Stochastic Unbiased Curvature-aided Gradient (SUCAG), for finite sum optimization problems. SUCAG constitutes an unbiased total gradient tracking technique that uses Hessian information to accelerate convergence. We analyze our method under the general asynchronous model of computation, in which each function is selected infinitely often with possibly unbounded (but sublinear) delay. For strongly convex problems, we establish linear convergence for the SUCAG method. When the initialization point is sufficiently close to the optimal solution, the established convergence rate is only dependent on the condition number of the problem, making it strictly faster than the known rate for the SAGA method. Furthermore, we describe a Markov-driven approach of implementing the SUCAG method in a distributed asynchronous multi-agent setting, via gossiping along a random walk on an undirected communication graph. We show that our analysis applies as long as the graph is connected and, notably, establishes an asymptotic linear convergence rate that is robust to the graph topology. Numerical results demonstrate the merits of our algorithm over existing methods. Copyright © 2018, The Authors. All rights reserved.

关键词： Stochastic systems

来源：评论

学校读者我要写书评

暂无评论

Nonlinear Smoothing of Data with Random Gaps and Outliers (DRAGO) Improves Estimation of Circadian Rhythm

Nonlinear Smoothing of Data with Random Gaps and Outliers (D...

引用

IEEE Signal Processing in Medicine and Biology Symposium (SPMB)

作者： A. Parekh I. W. Selesnick A. Baroni M. Miller B. Cavedoni H. Sanders A. W. Varga E. Blessing D. M. Rapoport I. Ayappa R. S. Osorio Department of Medicine Icahn School of Medicine at Mount Sinai Division of Pulmonary Critical Care and Sleep Medicine New York NY USA Department of Electrical and Computer Engineering NYU Tandon School of Engineering New York NY USA Department of Child and Adolescent Psychiatry NYU Langone Health New York NY USA Department of Psychiatry NYU Langone Health New York NY USA

ISBN: (数字)9781728143439

ISBN: (纸本)9781728143446

Core body temperature measurement using an ingestible pill has been proven effective for field-based ambulatory applications. The ingestible pill overcomes many impracticalities related with traditional methods of assessing core body temperature, however, it suffers from two key issues: random gaps due to missing data and outliers due to electromagnetic intereference. In this paper, we propose a principled convex optimization based framework for preprocessing the raw core body temperature signal. The proposed framework assumes that the raw core body temperature signal consists of two components: a smooth low-frequency component and a transient component with sparse outliers. We derive a computationally efficient algorithm using the majorization-minimization procedure and show its performance on simulated data. Finally, we demonstrate utility of the proposed method for estimating the circadian rhythm of core body temperature in cognitively normal elderly.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Controlling photonic spin Hall effect via exceptional points

引用

Physical Review B 2019年第11期100卷 115429-115429页

作者： Xinxing Zhou Xiao Lin Zhicheng Xiao Tony Low Andrea Alù Baile Zhang Handong Sun Division of Physics and Applied Physics School of Physical and Mathematical Sciences Nanyang Technological University Singapore 637371 Singapore Synergetic Innovation Center for Quantum Effects and Applications School of Physics and Electronics Hunan Normal University Changsha 410081 China Department of Electrical and Computer Engineering The University of Texas at Austin Austin Texas 78712 USA Department of Electrical and Computer Engineering University of Minnesota Minneapolis Minnesota 55455 USA Photonics Initiative Advanced Science Research Center City University of New York New York 10031 USA Centre for Disruptive Photonic Technologies (CDPT) School of Physical and Mathematical Sciences Nanyang Technological University Singapore 637371 Singapore MajuLab CNRS-UCA-SU-NUS-NTU International Joint Research Unit Singapore 637371 Singapore

The photonic spin Hall effect (SHE), featured by a spin-dependent transverse shift of an impinging optical beam driven by its polarization handedness, has many applications including precise metrology and spin-based nanophotonic devices. It is highly desirable to control and enhance the photonic SHE. However, such a goal remains elusive, due to the weak spin-orbit interaction of light, especially for systems with optical loss. Here we reveal a flexible way to modulate the photonic SHE via exceptional points, by exploiting the transverse shift in a parity-time (PT) symmetric system with balanced gain and loss. The underlying physics is associated with the near-zero value and abrupt phase jump of the reflection coefficients at exceptional points. We find that the transverse shift is zero at exceptional points, but it is largely enhanced in their vicinity. Moreover, the transverse shift switches its sign across the exceptional point, resulting from spontaneous PT-symmetry breaking. Due to the sensitivity of transverse shift at exceptional points, our work also indicates that the photonic SHE can enable a precise way to probe the location of exceptional point in photonic systems.

关键词： Light-matter interaction Metamaterials Nanophotonics Spin-orbit coupling PT-symmetry

来源：评论

学校读者我要写书评

暂无评论

Simultaneous Optical and electrical Spin-Torque Magnetometry with Phase-Sensitive Detection of Spin Precession

引用

Physical Review Applied 2019年第3期11卷 034047-034047页

作者： Yi Li Hilal Saglam Zhizhi Zhang Rao Bidthanapally Yuzan Xiong John E. Pearson Valentine Novosad Hongwei Qu Gopalan Srinivasan Axel Hoffmann Wei Zhang Department of Physics Oakland University Rochester Michigan 48309 USA Materials Science Division Argonne National Laboratory Argonne Illinois 60439 USA Department of Physics Illinois Institute of Technology Chicago Illinois 60616 USA School of Optical and Electronic Information Huazhong University of Science and Technology Wuhan 430074 China Department of Electrical and Computer Engineering Oakland University Rochester Michigan 48309 USA

Spin-based coherent information processing and encoding utilize the precession phase of spins in magnetic materials. However, the detection and manipulation of spin precession phases remain a major challenge for advanced spintronic functionalities. By using simultaneous electrical and optical detection, we demonstrate the direct measurement of the spin precession phase of a permalloy device driven by the spin-orbit torques from adjacent heavy metals. The spin Hall angle of the heavy metals can be independently determined from concurrent electrical and optical signals. The phase-sensitive optical detection also allows spatially-resolved measurements of local spin-torque parameters and ferromagnetic resonance with comprehensive amplitude and phase information. Our study offers a route toward future advanced characterizations of spin-torque oscillators, magnonic circuits, and tunneling junctions, where measuring the current-induced spin dynamics of individual nanomagnets is required.

关键词： Magnetization dynamics Spin torque Spin waves Spintronics Magnetic multilayers electrical techniques Magneto-optical Kerr effect Optically detected magnetic resonance

来源：评论

学校读者我要写书评

暂无评论

Transcutaneous Cervical Vagal Nerve Stimulation in Patients with Posttraumatic Stress Disorder (PTSD): A Pilot Study of Effects on PTSD Symptoms and Interleukin-6 Response to Stress

引用

Journal of Affective Disorders Reports 2021年 6卷 100190-100190页

作者： Bremner, J. Douglas Wittbrodt, Matthew T. Gurel, Nil Z. Shandhi, MdMobashir H. Gazi, Asim H. Jiao, Yunshen Levantsevych, Oleksiy M. Huang, Minxuan Beckwith, Joy Herring, Isaias Murrah, Nancy Driggers, Emily G. Ko, Yi-An Alkhalaf, MhmtJamil L. Soudan, Majd Shallenberger, Lucy Hankus, Allison N. Nye, Jonathon A. Park, Jeanie Woodbury, Anna Mehta, Puja K. Rapaport, Mark H. Vaccarino, Viola Shah, Amit J. Pearce, Bradley D. Inan, Omer T. Department of Psychiatry & Behavioral Sciences Emory University School of Medicine Atlanta Georgia Department of Radiology and Imaging Sciences Emory University School of Medicine Atlanta Georgia Atlanta VA Medical Center Decatur Georgia School of Electrical and Computer Engineering Georgia Institute of Technology Atlanta Georgia Department of Epidemiology Rollins School of Public Health Emory University Atlanta Georgia Department of Biostatistics and Bioinformatics Rollins School of Public Health Emory University Atlanta Georgia Department of Medicine Renal Division Emory University School of Medicine Atlanta Georgia Department of Anesthesiology Emory University School of Medicine Atlanta Georgia Department of Medicine Division of Cardiology Emory University School of Medicine Atlanta Georgia Huntsman Mental Health Institute Department of Psychiatry University of Utah School of Medicine Salt Lake City Utah United States Coulter Department of Bioengineering Georgia Institute of Technology Atlanta Georgia

Background: Posttraumatic stress disorder (PTSD) is a highly disabling condition associated with alterations in multiple neurobiological systems, including increases in inflammatory and sympathetic function, responsible for maintenance of symptoms. Treatment options including medications and psychotherapies have limitations. We previously showed that transcutaneous Vagus Nerve Stimulation (tcVNS) blocks inflammatory (interleukin (IL)-6) responses to stress in PTSD. The purpose of this study was to assess the effects of tcVNS on PTSD symptoms and inflammatory responses to stress. Methods: Twenty patients with PTSD were randomized to double blind active tcVNS (N=9) or sham (N=11) stimulation in conjunction with exposure to personalized traumatic scripts immediately followed by active or sham tcVNS and measurement of IL-6 and other biomarkers of inflammation. Patients then self administered active or sham tcVNS twice daily for three months. PTSD symptoms were measured with the PTSD Checklist (PCL) and the Clinician Administered PTSD Scale (CAPS), clinical improvement with the Clinical Global Index (CGI) and anxiety with the Hamilton Anxiety Scale (Ham-A) at baseline and one-month intervals followed by a repeat of measurement of biomarkers with traumatic scripts. After three months patients self treated with twice daily open label active tcVNS for another three months followed by assessment with the CGI. Results: Traumatic scripts increased IL-6 in PTSD patients, an effect that was blocked by tcVNS (p<.05). Active tcVNS treatment for three months resulted in a 31% greater reduction in PTSD symptoms compared to sham treatment as measured by the PCL (p=0.013) as well as hyperarousal symptoms and somatic anxiety measured with the Ham-A p<0.05). IL-6 increased from baseline in sham but not tcVNS. Open label tcVNS resulted in improvements measured with the CGI compared to the sham treatment period p<0.05). Conclusions: These preliminary results suggest that tcVNS reduces inf

关键词：

来源：评论

学校读者我要写书评

暂无评论

P086 The organization of sleep-wake patterns around daily schedules in college students

引用

Sleep Advances 2021年第SUPPLEMENT_1期2卷 A49-A49页

作者： Lu, S Klerman, E Stone, J McHill, A Barger, L Sano, A Czeisler, C Rajaratnam, S Phillips, A Turner Institute for Brain and Mental Health School of Psychological Sciences Monash University Clayton Australia Department of Neurology Massachusetts General Hospital Boston USA Division of Sleep and Circadian Disorders Departments of Medicine and Neurology Brigham and Women’s Hospital Boston USA Division of Sleep Medicine Harvard Medical School Boston USA Oregon Institute of Occupational Health Sciences Oregon Health and Science University Portland USA Department of Electrical and Computer Engineering Rice University Houston USA

A potential contributor to insufficient sleep among college students is their daily schedule, with sleep sacrificed for other waking activities. We investigated how daily schedules predict day-to-day sleep-wake timing in college students. 223 undergraduate college students (M±SD = 19.2±1.4 years, 37% females) attending a Massachusetts university in the US between 2013–2016 were monitored for approximately 30 days during semester. Sleep-wake timing was measured using daily online sleep diaries and wrist-actigraphy. Daily schedules were measured using daily online diaries that included self-reported timing and duration of academic, exercise-based, and extracurricular activities, and duration of self-study. Linear mixed models were used to examine the association between sleep-wake patterns and daily schedules at both the between-person and within-person levels. An earlier start time of the first-reported activity predicted earlier sleep onset (between and within: p<.001) and shorter total sleep time (within: p<.001) for the previous night, as well as earlier wake onset on the corresponding day (between and within: p<.001). A later end time of the last-reported activity predicted later sleep onset (within: p=.002) and shorter total sleep time (within: p=.02) on that night. A more intense daily schedule (i.e., greater total duration of reported activities) predicted an earlier wake onset time (between: p=.003, within: p<.001), a later sleep onset time (within: p<.001), a shortened total night-time sleep duration (between: p=.03, within: p<.001), and greater sleep efficiency (within: p<.001). These results indicate that college students may organize their sleep and wake times based on their daily schedule.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Compact CPW fed switchable UWB antenna as an antenna filter at narrow-frequency bands

引用

Progress In Electromagnetics Research C 2018年 81卷 199-209页

作者： Nejatijahromi, Mansour Naghshvarianjahromi, Mahdi Rahman, Muhibur Department of Electrical Engineering Islamic Azad University Tehran South Branch and Shahidsattaryeronatical University of Science and Technology Tehran Iran Division of Electrical and Electronics Engineering Dongguk University Seoul Korea Republic of Department of Electrical and Computer Engineering McMaster University HamiltonONL8S 4L8 Canada

The aim of this paper is to present a compact coplanar waveguide (CPW) fed switchable UWB antenna as an antenna filter with adjustable notched frequency bands. Novel miniaturized tunable resonators are also presented to achieve notched bands. The antenna is made tunable in notched frequency bands without any modification in the basic structure. These stopbands are made tunable just by varying values of the capacitors according to our desired applications. The antenna structure is very compact having overall dimensions of 24 × 30.5 mm2 with partial ground plane. The proposed small size, variable, low cost and low weight antenna with good propagation characteristics will pave the way for UWB wireless communication applications. © 2018, Electromagnetics Academy. All rights reserved.

关键词： Coplanar waveguides

来源：评论

学校读者我要写书评

暂无评论

Recursive Singular Spectrum Analysis Applied to the Design of a Trading System

Recursive Singular Spectrum Analysis Applied to the Design o...

引用

Annual IEEE Systems Conference

作者： Michel C. R. Leles Adriano S. Vale-Cardoso Mariana G. Moreira Elton F. Sbruzzi Cairo L. Nascimento Leonardo A. Mozelli Homero N. Guimarães Department of Technology Federal University of São João del-Rei Ouro Branco - MG Brazil Division of Computer Science Instituto Tecnológico de Aeronáutica São José dos Campos - SP Brazil Division of Electronic Engineering Instituto Tecnológico de Aeronáutica São José dos Campos - SP Brazil Department of Electronic Engineering Federal University of Minas Gerais Belo Horizonte - MG Brazil Department of Electrical Engineering Federal University of Minas Gerais Belo Horizonte - MG Brazil

Singular Spectrum Analysis (SSA) is a nonparametric approach that can be used to decompose a time series as trends, oscillations and noise. In online applications, the SSA algorithm must be recalculated for each new sample available. The so called Causal SSA have been used in this context. In this manuscript, an alternative version of online SSA, the Recursive SSA, is proposed as a technical indicator. Based on a “forgetting factor” parameter, it is possible to control the amount of previous samples that are used in the SSA algorithm. This functionality may confer adaptive and hybrid features, thereby providing a crucial characteristic to technical indicators. The Recursive SSA technical trading rules (SSA-TTR) are applied to the DJIA time-series and compared against popular technical indicators. The results show the advantages of SSA-TTR over the popular ones.

关键词： Time series analysis Oscillators Market research Spectral analysis Matrix decomposition Trajectory Economics

来源：评论

学校读者我要写书评

暂无评论

2022 Review of Data-Driven Plasma Science

arXiv

引用

arXiv 2022年

作者： Anirudh, Rushil Archibald, Rick Asif, M. Salman Becker, Markus M. Benkadda, Sadruddin Bremer, Peer-Timo Budé, Rick H.S. Chang, C.S. Chen, Lei Churchill, R.M. Citrin, Jonathan Gaffney, Jim A. Gainaru, Ana Gekelman, Walter Gibbs, Tom Hamaguchi, Satoshi Hill, Christian Humbird, Kelli Jalas, Sören Kawaguchi, Satoru Kim, Gon-Ho Kirchen, Manuel Klasky, Scott Kline, John L. Krushelnick, Karl Kustowski, Bogdan Lapenta, Giovanni Li, Wenting Ma, Tammy Mason, Nigel J. Mesbah, Ali Michoski, Craig Munson, Todd Murakami, Izumi Najm, Habib N. Erik J. Olofsson, K. Park, Seolhye Peterson, J. Luc Probst, Michael Pugmire, David Sammuli, Brian Sawlani, Kapil Scheinker, Alexander Schissel, David P. Shalloo, Rob J. Shinagawa, Jun Seong, Jaegu Spears, Brian K. Tennyson, Jonathan Thiagarajan, Jayaraman Ticoş, Catalin M. Trieschmann, Jan van Dijk, Jan Van Essen, Brian Ventzek, Peter Wang, Haimin Wang, Jason T.L. Wang, Zhehui Wende, Kristian Xu, Xueqiao Yamada, Hiroshi Yokoyama, Tatsuya Zhang, Xinhua Lawrence Livermore National Laboratory LivermoreCA94550 United States Oak Ridge National Laboratory Oak RidgeTN37830 United States University of California Riverside RiversideCA92521 United States Felix-Hausdorff-Str. 2 Greifswald17489 Germany Aix Marseille University CNRS PIIM UMR 7345 Marseille France Department of Applied Physics Eindhoven University of Technology Netherlands Princeton Plasma Physics Laboratory Princeton NJ08540 United States Institute of Ion Physics and Applied Physics University of Innsbruck Technikerstrasse 25 Innsbruck6020 Austria DIFFER - Dutch Institute for Fundamental Energy Research Eindhoven Netherlands Science and Technology of Nuclear Fusion Group Eindhoven University of Technology Eindhoven Netherlands Department of Physics and Astronomy University of California Los AngelesCA90095 United States NVIDIA 2788 San Tomas Expressway Santa ClaraCA95051 United States Center for Atomic and Molecular Technologies Graduate School of Engineering Osaka University 2-1 Yamadaoka Suita Osaka Japan Department of Nuclear Sciences and Applications International Atomic Energy Agency Wagramer Strasse 5 PO Box 100 Vienna1400 Austria Center for Free-Electron Laser Science Department of Physics Universität Hamburg Luruper Chaussee 149 Hamburg22761 Germany Division of Information and Electronic Engineering Graduate School of Engineering Muroran Institute of Technology Hokkaido Muroran050-8585 Japan Seoul National University Seoul151-741 Korea Republic of Deutsches Elektronen-Synchrotron DESY Notkestr. 85 Hamburg22607 Germany Los Alamos National Laboratory Los AlamosNM87545 United States Center for Ultrafast Optical Science University of Michigan Ann ArborMI48109-2099 United States Department of Mathematics KULeuven University of Leuven Belgium Department of Physical Sciences The University of Kent CanterburyCT2 7NH United Kingdom Department of Chemical and Biomolecular Engineering University of California Berk

Data science and technology offer transformative tools and methods to science. This review article highlights latest development and progress in the interdisciplinary field of data-driven plasma science (DDPS). A large amount of data and machine learning algorithms go hand in hand. Most plasma data, whether experimental, observational or computational, are generated or collected by machines today. It is now becoming impractical for humans to analyze all the data manually. Therefore, it is imperative to train machines to analyze and interpret (eventually) such data as intelligently as humans but far more efficiently in quantity. Despite the recent impressive progress in applications of data science to plasma science and technology, the emerging field of DDPS is still in its infancy. Fueled by some of the most challenging problems such as fusion energy, plasma-processing of materials, and fundamental understanding of the universe through observable plasma phenomena, it is expected that DDPS continues to benefit significantly from the interdisciplinary marriage between plasma science and data science into the foreseeable future. Copyright © 2022, The Authors. All rights reserved.

关键词： Machine learning

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：