检索结果-内蒙古大学图书馆

CLEO: Fundamental Science, CLEO:FS 2024 - Part of Conference on Lasers and Electro-Optics, CLEO 2024

作者： Cheng, Jing Niherysh, Kiryl A. Francis, Peter Chakraborty, Debamitra Lombardi, Floriana Erts, Donats Prischepa, Serghej L. Laszcz, Adam Komissarov, Ivan V. Sobolewski, Roman Materials Science Graduate Program University of Rochester RochesterNY14627 United States Laboratory for Laser Energetics University of Rochester RochesterNY14623-1299 United States Department of Microtechnology and Nanoscience Chalmers University of Technology Gothenburg Sweden Institute of Chemical Physics University of Latvia Riga Latvia Department of Electrical and Computer Engineering University of Rochester RochesterNY14627 United States Dipartimento di Fisica "E.R. Caianiello" Università degli Studi di Salerno Sa FiscianoI-84084 Italy Lukasiewicz Research Network Institute of Microelectronics and Photonics WarszawaPL-02668 Poland

ISBN: (纸本)9781957171395

The dynamics of coherent acoustic phonons in the Bi2Se3 layered crystal system are investigated. The findings reveal that the frequency evolution of breathing modes with the number of the material quintuple layers and the dispersion relation both can be explained by a modified chain model with a nonuniform coupling force. © Optica Publishing Group 2024, © 2024 The Author(s)

关键词： Ultrathin films

来源：评论

学校读者我要写书评

暂无评论

New Frontiers for Wave engineering Using Metamaterials

New Frontiers for Wave Engineering Using Metamaterials

引用

2022年全国微波毫米波会议

作者： Andrea Alù Photonics Initiative Advanced Science Research Center City University of New York Physics Program Graduate Center City University of New York Department of Electrical and Computer Engineering City College of New York

Metamaterials are engineered materials with properties that go well beyond what offered by nature, providing unprecedented opportunities to tailor and enhance the control of waves. In this talk, I discuss our recent activity at microwaves and THz frequencies, showing how suitably tailored meta-atoms and their arrangements open exciting avenues for wave manipulation, including metasurfaces with enhanced wavefront manipulation, and magnet-free nonreciprocity and topological phenomena. Insights into the underlying physics and new devices based on these concepts will be presented.

关键词： New Frontiers for Wave engineering Using Metamaterials

来源：评论

学校读者我要写书评

暂无评论

Inverse-Designed Optical Metagratings for Free-Space Integral Equations Solving

Inverse-Designed Optical Metagratings for Free-Space Integra...

引用

Conference on Lasers and Electro-Optics Europe (CLEO EUROPE)

作者： Andrea Cordaro Brian Edwards Vahid Nikkhah Andrea Alù Nader Engheta Albert Polman Institute of Physics University of Amsterdam Amsterdam The Netherlands Center for Nanophotonics NWO-Institute AMOLF Amsterdam The Netherlands Department of Electrical and Systems Engineering University of Pennsylvania Philadelphia USA Photonics Initiative Advanced Science Research Center City University of New York New York USA Physics Program Graduate Center City University of New York New York USA

ISBN: (纸本)9798350345995

The world's ever-growing need for efficient computing has been driving researchers from diverse research fields to explore alternatives to the current digital computing paradigm. In this context, the field of all-optical analog processing is gaining significant attention opening new possibilities to overcome the bottlenecks of standard microelectronics [1–5]. We present a Si-based optical metastructure that solves Fredholm integral equations of the second kind in a fully analog fashion at optical frequencies. We exploit the analogy between the integral equation solving and the behavior of an optimized periodic metagrating coupled to a feedback system. At the foundations of this mapping lies the possibility of designing the S-matrix of a periodic structure by setting its periodicity (i.e., the number of input/output modes and hence the dimension of the S-matrix) and optimizing its unit cell (i.e., optimizing the coupling of light into the defined diffraction modes in amplitude and phase), as shown in Fig. 1a. Next, we show how the designed metastructure effectively solves the problem of interest and compare the metasurface-based solution to the ideal solution. We show that electron beam lithography and reactive ion etching provide the spatial resolution required to create a hardware representation of a predefined Kernel, with relatively small deviations between experiments and simulations. We optically characterize the output for different input signals showing good agreement with the ideal simulated response and use the data to retrieve the solution experimentally provided by the metadevice (see Fig. 1b). Fig. 1 A. Schematic of the proposed structure. A silicon metasurface is patterned on top of a sapphire substrate. The superstrate consists of $\text{SiO}_{2}$ with a semi-transparent au mirror on top. Scale-bar 500 nm b. Estimate of the solution to the integral equation obtained by the fabricated metadevice.

关键词： Crosstalk Electron beam lithography Light diffraction Modes Phase Spatial resolution

来源：评论

学校读者我要写书评

暂无评论

Numerical Experiment of Adding Patch Elements to X-band Microstrip Antennas

Numerical Experiment of Adding Patch Elements to X-band Micr...

引用

International RF and Microwave Conference, RFM

作者： Yusnita Rahayu Anhar Saktioto Irsan Taufik Ali Yussi Perdana Saputera M Novriza Teguh Praludi Department of Electrical Engineering Faculty of Engineering Universitas Riau Pekanbaru Indonesia Physics Dept. FMIPA Universitas Riau Pekanbaru Indonesia Doctoral Defense Post Graduate Program Universitas Brawijaya Malang Indonesia National Research and Innovation Agency Indonesia

This paper compares single microstrip antenna designs and microstrip arrays used for Manpack Radar with X-band frequency. Antenna array configurations were investigated for 1x2, 1x4, and 1x32 elements. A gain increase is required for each additional patch element. Patch dimensions are set at 9.17 x 10.10 x 0.035 mm. The parameters needed are X-Band frequency with gain >15 dBi, beamwidth angle of ≤5°, and bandwidth of more than 60 MHz. The simulation results show a good match with the target required for the 9.3 GHz frequency. The largest gain value numerically is obtained on the antenna with 32 patches, which is 17.1 dBi.

关键词： Radio frequency Microstrip antenna arrays Azimuth Simulation Microstrip antennas Radar Bandwidth

来源：评论

学校读者我要写书评

暂无评论

Functional Connectivity Analysis of Visually Evoked ERPs for Mild Cognitive Impairment: Pilot Study

Functional Connectivity Analysis of Visually Evoked ERPs for...

引用

Annual International Conference of the IEEE engineering in Medicine and Biology Society (EMBC)

作者： M. Antar L. Wang A. Tran A. White P. Williams B. Sylcott J. C. Mizelle S. Kim Biomedical Engineering and Cognitive Neuroscience (BEACON) Laboratory East Carolina University Greenville NC USA College of Engineering and Technology East Carolina University Greenville NC USA Medical Physics Graduate Program Duke University Durham NC USA Department of Kinesiology College of Health and Human Performance East Carolina University Greenville NC USA

Mild cognitive impairment (MCI) is considered the early stage of Alzheimer's disease, characterized as mild memory loss. A novel method of functional connectivity (FC) analysis can be used to detect MCI before memory is significantly impaired allowing for preventative measures to be taken. FC examines interactions between EEG channels to grant insight on underlying neural networks and analyze the effects of MCI. Applying FC method of weighted phase lag index (wPLI) to P300 ERPs provided insight on the link between the pathology of Alzheimer's disease and cognitive loss. wPLI was analyzed per frequency band (θ, α, μ, β) and by channel combination groups (intra-hemispheric short, intra-hemispheric long, inter-hemispheric short, inter-hemispheric long, transverse). MCI was found to have a statistically significant lower ΔwPLI P300 compared to normal controls in the μ intra-hemispheric short (p = 0.0286), μ intra-hemispheric long (p = 0.0477), μ inter-hemispheric short (p = 0.0018) and the α intra-hemispheric short (p = 0.0423). Results indicate a possible deficiency in the dorsal visual processing pathway among MCI subjects as well as an unbalanced coordination between the two hemispheres.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Stationary Charge Radiation in Anisotropic Photonic Time Crystals

引用

Physical Review Letters 2023年第9期130卷 093803-093803页

作者： Huanan Li Shixiong Yin Huan He Jingjun Xu Andrea Alù Boris Shapiro MOE Key Laboratory of Weak-Light Nonlinear Photonics School of Physics Nankai University Tianjin 300071 China Photonics Initiative Advanced Science Research Center City University of New York New York New York 10031 USA Department of Electrical Engineering City College of The City University of New York New York New York 10031 USA Physics Program Graduate Center City University of New York New York New York 10016 USA Department of Physics Technion-Israel Institute of Technology Haifa 32000 Israel

Time metamaterials offer a great potential for wave manipulation, drawing increasing attention in recent years. Here, we explore the exotic wave dynamics of an anisotropic photonic time crystal (APTC) formed by an anisotropic medium whose optical properties are uniformly and periodically changed in time. Based on a temporal transfer matrix formalism, we show that a stationary charge embedded in an APTC emits radiation, in contrast to the case of isotropic photonic time crystals, and its distribution in momentum space is controlled by the APTC band structure. Our approach extends the functionalities of time metamaterials, offering new opportunities for radiation generation and control, with implications for both classical and quantum applications.

关键词： Optical pumping Photonic crystals Photonics Time crystals

来源：评论

学校读者我要写书评

暂无评论

Modifying BiVO4 as a photocatalyst for water oxidation using constant-duration alkaline-etched post treatments

引用

New Journal of Chemistry 2023年第2期48卷 569-577页

作者： Hsu, Chuan-Chih Chuang, Kai-Jie Huang, Hsiao-Wen Pan, Bo-Jin Chen, Hung-Ming Husain, Sadang Yougbaré, Sibidou Hsiao, Yu-Cheng Wu, Yung-Fu Lin, Lu-Yin Division of Cardiovascular Surgery Department of Surgery School of Medicine College of Medicine Taipei Medical University Taiwan Division of Cardiovascular Surgery Department of Surgery Taipei Medical University Hospital Taiwan Department of Chemical Engineering and Biotechnology National Taipei University of Technology Taipei Taiwan Department of Chemical Engineering Ming Chi University of Technology New Taipei City24301 Taiwan Gingen Technology Co. Ltd. Rm. 7 10F. No. 189 Sec. 2 Keelung Rd. Xinyi Dist. Taipei11054 Taiwan Department of Physics Faculty of Mathematics and Natural Science Lambung Mangkurat University Banjarmasin70124 Indonesia /Nanoro Ouagadougou03 Burkina Faso International PhD Program in Biomedical Engineering College of Biomedical Engineering Taipei Medical University Taipei11031 Taiwan Stanford Byers Center for Biodesign Stanford University CA94305-5428 United States Graduate Institute of Biomedical Optomechatronics College of Biomedical Engineering Taipei Medical University Taipei11031 Taiwan Cell Physiology and Molecular Image Research Center Wan Fang Hospital Taipei Medical University Taipei11696 Taiwan

BiVO4 with suitable band edges and a small band gap is considered an efficient photocatalyst for the oxygen evolution reaction (OER), but short charge-transfer lengths limit its photocatalytic ability. Increasing active sites can essentially enhance oxidation reactions and photocatalytic ability. The alkaline etching technique can refine the surface properties of BiVO4 by introducing oxygen vacancies and possibly establishing a heterojunction, but suitable alkaline etching methods are rarely discussed. In this study, three alkaline etching methods, including hydrothermal, soaking, and electrodeposition processes, are first applied for a constant duration to tailor the surface properties of BiVO4 as a photocatalyst for the OER. Alkaline-etched BiVO4 prepared using hydrothermal and soaking processes shows better photocatalytic abilities due to the generation of additional oxygen vacancies, while poor photocatalytic ability is found for that fabricated using electrodeposition due to the formation of less photocatalytic VO2. The highest photocurrent density of 2.38 mA cm−2 is obtained at 1.23 V versus a reversible hydrogen electrode in an electrolyte without a hole scavenger for the BiVO4 etched in the hydrothermal process, while the untreated BiVO4 presents a photocurrent density of 0.58 mA cm−2. A photocurrent retention of 92.3% is achieved after 5000 seconds of continuous illumination. The study supplies blueprints for establishing effective alkaline etching methods for enhancing the photocatalytic ability of BiVO4, with the exception of time costs. © 2024 The Royal Society of Chemistry.

关键词： Charge transfer

来源：评论

学校读者我要写书评

暂无评论

Tuning the Size and Stiffness of Inflatable Particles

arXiv

引用

arXiv 2025年

作者： Pashine, Nidhi Wang, Dong Baines, Robert Goyal, Medha Shattuck, Mark D. O’Hern, Corey S. Kramer-Bottiglio, Rebecca Department of Mechanical Engineering Yale University New HavenCT06520 United States Department of Physics BioInspired Institute Syracuse University SyracuseNY13244 United States Department of Physics Benjamin Levich Institute City College of New York New York CityNY10031 United States Department of Physics Yale University New HavenCT06520 United States Department of Applied Physics Yale University New HavenCT06520 United States Graduate Program in Computational Biology & Biomedical Informatics Yale University New HavenCT06520 United States

We describe size-varying cylindrical particles made from silicone elastomers that can serve as building blocks for robotic granular materials. The particle size variation, which is achieved by inflation, gives rise to changes in stiffness under compression. We design and fabricate inflatable particles that can become stiffer or softer during inflation, depending on key parameters of the particle geometry, such as the ratio of the fillet radius to the wall thickness, r/t. We also conduct numerical simulations of the inflatable particles and show that they only soften during inflation when localization of large strains occurs in the regime r/t → 0. This work introduces novel particle systems with tunable size and stiffness that can be implemented in numerous soft robotic applications. © 2025, CC BY.

关键词： Stiffness

来源：评论

学校读者我要写书评

暂无评论

Temporal refraction and reflection in modulated mechanical metabeams: theory and physical observation

arXiv

引用

arXiv 2025年

作者： Wang, Shaoyun Shao, Nan Chen, Hui Chen, Jiaji Qian, Honghua Wu, Qian Duan, Huiling Alù, Andrea Huang, Guoliang Department of Mechanical and Aerospace Engineering University of Missouri ColumbiaMO65211 United States Center for Mechanics Plus Under Extreme Environments School of Mechanical Engineering and Mechanics Ningbo University Ningbo315211 China Photonics Initiative Advanced Science Research Center City University of New York New YorkNY United States Physics Program Graduate Center City University of New York New YorkNY United States Department of Mechanics and Engineering Science College of Engineering Peking University Beijing100871 China

Wave reflection and refraction at a time interface follow different conservation laws compared to conventional scattering at a spatial interface. This study presents the experimental demonstration of refraction and reflection of flexural waves across a temporal boundary in a continuum-based mechanical metabeam, and unveils opportunities that emerge by tailoring temporal scattering phenomena for phononic applications. We observe these phenomena in an elastic beam attached to an array of piezoelectric patches that can vary in time the effective elastic properties of the beam. Frequency conversion and phase conjugation are observed upon a single temporal interface. These results are consistent with the temporal Snell’s law and Fresnel equations for temporal interfaces. Further, we illustrate the manipulation of amplitude and frequency spectra of flexural wave temporal refraction and reflection through multi-stepped temporal interfaces. Finally, by implementing a smooth time variation of wave impedance, we numerically and experimentally demonstrate the capabilities of the temporal metabeam to realize waveform morphing and information coding. Our findings lay the foundation for developing time-mechanical metamaterials and time-phononic crystals, offering new avenues for advanced phonon manipulation in both wave amplitude and frequency. © 2025, CC BY.

关键词： Phonons

来源：评论

学校读者我要写书评

暂无评论

Chiral metal-organic framework based spin-polarized flexible photodetector with ultrahigh sensitivity

引用

Materials Today Nano 2023年 21卷

作者： Mustaqeem, M. Kamal, S. Ahmad, N. Chou, P.-T. Lin, K.-H. Huang, Y.-C. Guo, G.-Y. Paul Inbaraj, C.R. Li, W.-K. Yao, H.-C. Lu, K.-L. Chen, Y.-F. Department of Chemistry National Taiwan University No. 1 Section 4 Roosevelt Rd Taipei10617 Department of Physics National Taiwan University No. 1 Section 4 Roosevelt Rd Taipei10617 Nano-Science and Technology Program Taiwan International Graduate Program Institute of Physics Academia Sinica Taipei106 Taiwan Institute of Chemistry Academia Sinica Taipei115 Taiwan Department of Materials Science and Engineering National Taiwan University of Science and Technology Taipei10607 Taiwan Institute of Physics Academia Sinica Taipei11529 Taiwan Department of Materials Engineering Ming Chi University of Technology

Spin-optoelectronics plays a key role in developing next-generation technologies with potential applications covering from pharmaceutical synthesis and quantum computing to optical communication. One of the most feasible ways to achieve high-performance spin optoelectronic devices is based on chiral materials. Chiral metal-organic frameworks (CMOFs), an emerging class of chiral hybrid materials, have sparked interest due to their structural variety and flexibility, order nanopores, cost-effectiveness, and unique chirality features. Herein, we have developed CMOF [Sr (9,10-adc) (DMAc)2]n based on achiral building blocks [(9,10-adc)] to detect circularly polarized light (CPL) with ultrahigh sensitivity. Their application in spin-polarized flexible detectors gives a detectivity (D∗) as high as 1.83 × 1012 jones, superior to all reported heterochiral MOF-based detectors. Meanwhile, the anisotropy factor (gIph) is up to 0.38 for CPL detection. The maximum photoresponsivity (Rph) and photogain (η) values of CMOFs reach up to 6.0 × 105 (A/W) and 1.8 × 106, respectively, which are also the record values among reported chiral MOFs. Additionally, the photodetector is mechanically flexible and durable, manifesting an important feature for wearable devices. Therefore, our study shown here is significant and timely to open a route for advancing spin-optoelectronics based on CMOF. © 2023 Elsevier Ltd

关键词： Photodetectors

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：