A Review of Tunable Acoustic Metamaterials
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Gold Nanoarray Deposited Using Alternating Current for Emission Rate
Xue et al. Nanoscale Research Letters 2013, 8:295 http://www.nanoscalereslett.com/content/8/1/295 NANO EXPRESS Open Access Gold nanoarray deposited using alternating current for emission rate-manipulating nanoantenna Jiancai Xue1, Qiangzhong Zhu1, Jiaming Liu1, Yinyin Li2, Zhang-Kai Zhou1*, Zhaoyong Lin1, Jiahao Yan1, Juntao Li1 and Xue-Hua Wang1* Abstract We have proposed an easy and controllable method to prepare highly ordered Au nanoarray by pulse alternating current deposition in anodic aluminum oxide template. Using the ultraviolet–visible-near-infrared region spectrophotometer, finite difference time domain, and Green function method, we experimentally and theoretically investigated the surface plasmon resonance, electric field distribution, and local density of states enhancement of the uniform Au nanoarray system. The time-resolved photoluminescence spectra of quantum dots show that the emission rate increased from 0.0429 to 0.5 ns−1 (10.7 times larger) by the existence of the Au nanoarray. Our findings not only suggest a convenient method for ordered nanoarray growth but also prove the utilization of the Au nanoarray for light emission-manipulating antennas, which can help build various functional plasmonic nanodevices. Keywords: Anodic aluminum oxide template, Au nanoarray, Emission rate, Nanoantenna, Surface plasmon PACS: 82.45.Yz, 78.47.jd, 62.23.Pq Background Owing to the self-organized hexagonal arrays of Excited by an incident photon beam and provoking a uniform parallel nanochannels, anodic aluminum oxide collective oscillation of free electron gas, plasmonic (AAO) film has been widely used as the template for materials gain the ability to manipulate electromagnetic nanoarray growth [26-29]. Many distinctive discoveries field at a deep-subwavelength scale, making them play a have been made in the nanosystems fabricated in AAO major role in current nanoscience [1-5]. -
A Review of Electric Impedance Matching Techniques for Piezoelectric Sensors, Actuators and Transducers
Review A Review of Electric Impedance Matching Techniques for Piezoelectric Sensors, Actuators and Transducers Vivek T. Rathod Department of Electrical and Computer Engineering, Michigan State University, East Lansing, MI 48824, USA; [email protected]; Tel.: +1-517-249-5207 Received: 29 December 2018; Accepted: 29 January 2019; Published: 1 February 2019 Abstract: Any electric transmission lines involving the transfer of power or electric signal requires the matching of electric parameters with the driver, source, cable, or the receiver electronics. Proceeding with the design of electric impedance matching circuit for piezoelectric sensors, actuators, and transducers require careful consideration of the frequencies of operation, transmitter or receiver impedance, power supply or driver impedance and the impedance of the receiver electronics. This paper reviews the techniques available for matching the electric impedance of piezoelectric sensors, actuators, and transducers with their accessories like amplifiers, cables, power supply, receiver electronics and power storage. The techniques related to the design of power supply, preamplifier, cable, matching circuits for electric impedance matching with sensors, actuators, and transducers have been presented. The paper begins with the common tools, models, and material properties used for the design of electric impedance matching. Common analytical and numerical methods used to develop electric impedance matching networks have been reviewed. The role and importance of electrical impedance matching on the overall performance of the transducer system have been emphasized throughout. The paper reviews the common methods and new methods reported for electrical impedance matching for specific applications. The paper concludes with special applications and future perspectives considering the recent advancements in materials and electronics. -
Bringing Optical Metamaterials to Reality
UC Berkeley UC Berkeley Electronic Theses and Dissertations Title Bringing Optical Metamaterials to Reality Permalink https://escholarship.org/uc/item/5d37803w Author Valentine, Jason Gage Publication Date 2010 Peer reviewed|Thesis/dissertation eScholarship.org Powered by the California Digital Library University of California Bringing Optical Metamaterials to Reality By Jason Gage Valentine A dissertation in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Engineering – Mechanical Engineering in the Graduate Division of the University of California, Berkeley Committee in charge: Professor Xiang Zhang, Chair Professor Costas Grigoropoulos Professor Liwei Lin Professor Ming Wu Fall 2010 Bringing Optical Metamaterials to Reality © 2010 By Jason Gage Valentine Abstract Bringing Optical Metamaterials to Reality by Jason Gage Valentine Doctor of Philosophy in Mechanical Engineering University of California, Berkeley Professor Xiang Zhang, Chair Metamaterials, which are artificially engineered composites, have been shown to exhibit electromagnetic properties not attainable with naturally occurring materials. The use of such materials has been proposed for numerous applications including sub-diffraction limit imaging and electromagnetic cloaking. While these materials were first developed to work at microwave frequencies, scaling them to optical wavelengths has involved both fundamental and engineering challenges. Among these challenges, optical metamaterials tend to absorb a large amount of the incident light and furthermore, achieving devices with such materials has been difficult due to fabrication constraints associated with their nanoscale architectures. The objective of this dissertation is to describe the progress that I have made in overcoming these challenges in achieving low loss optical metamaterials and associated devices. The first part of the dissertation details the development of the first bulk optical metamaterial with a negative index of refraction. -
Electrical Impedance Tomography
INSTITUTE OF PHYSICS PUBLISHING INVERSE PROBLEMS Inverse Problems 18 (2002) R99–R136 PII: S0266-5611(02)95228-7 TOPICAL REVIEW Electrical impedance tomography Liliana Borcea Computational and Applied Mathematics, MS 134, Rice University, 6100 Main Street, Houston, TX 77005-1892, USA E-mail: [email protected] Received 16 May 2002, in final form 4 September 2002 Published 25 October 2002 Online at stacks.iop.org/IP/18/R99 Abstract We review theoretical and numerical studies of the inverse problem of electrical impedance tomographywhich seeks the electrical conductivity and permittivity inside a body, given simultaneous measurements of electrical currents and potentials at the boundary. (Some figures in this article are in colour only in the electronic version) 1. Introduction Electrical properties such as the electrical conductivity σ and the electric permittivity , determine the behaviour of materials under the influence of external electric fields. For example, conductive materials have a high electrical conductivity and both direct and alternating currents flow easily through them. Dielectric materials have a large electric permittivity and they allow passage of only alternating electric currents. Let us consider a bounded, simply connected set ⊂ Rd ,ford 2and, at frequency ω, let γ be the complex admittivity function √ γ(x,ω)= σ(x) +iω(x), where i = −1. (1.1) The electrical impedance is the inverse of γ(x) and it measures the ratio between the electric field and the electric current at location x ∈ .Electrical impedance tomography (EIT) is the inverse problem of determining the impedance in the interior of ,givensimultaneous measurements of direct or alternating electric currents and voltages at the boundary ∂. -
Impedance Matching
Impedance Matching Advanced Energy Industries, Inc. Introduction The plasma industry uses process power over a wide range of frequencies: from DC to several gigahertz. A variety of methods are used to couple the process power into the plasma load, that is, to transform the impedance of the plasma chamber to meet the requirements of the power supply. A plasma can be electrically represented as a diode, a resistor, Table of Contents and a capacitor in parallel, as shown in Figure 1. Transformers 3 Step Up or Step Down? 3 Forward Power, Reflected Power, Load Power 4 Impedance Matching Networks (Tuners) 4 Series Elements 5 Shunt Elements 5 Conversion Between Elements 5 Smith Charts 6 Using Smith Charts 11 Figure 1. Simplified electrical model of plasma ©2020 Advanced Energy Industries, Inc. IMPEDANCE MATCHING Although this is a very simple model, it represents the basic characteristics of a plasma. The diode effects arise from the fact that the electrons can move much faster than the ions (because the electrons are much lighter). The diode effects can cause a lot of harmonics (multiples of the input frequency) to be generated. These effects are dependent on the process and the chamber, and are of secondary concern when designing a matching network. Most AC generators are designed to operate into a 50 Ω load because that is the standard the industry has settled on for measuring and transferring high-frequency electrical power. The function of an impedance matching network, then, is to transform the resistive and capacitive characteristics of the plasma to 50 Ω, thus matching the load impedance to the AC generator’s impedance. -
TWO MODELS of ELECTRICAL IMPEDANCE for ELECTRODES with TAP WATER and THEIR CAPABILITY to RECORD GAS VOLUME FRACTION Revista Mexicana De Ingeniería Química, Vol
Revista Mexicana de Ingeniería Química ISSN: 1665-2738 [email protected] Universidad Autónoma Metropolitana Unidad Iztapalapa México Rodríguez-Sierra, J.C.; Soria, A. TWO MODELS OF ELECTRICAL IMPEDANCE FOR ELECTRODES WITH TAP WATER AND THEIR CAPABILITY TO RECORD GAS VOLUME FRACTION Revista Mexicana de Ingeniería Química, vol. 15, núm. 2, 2016, pp. 543-551 Universidad Autónoma Metropolitana Unidad Iztapalapa Distrito Federal, México Available in: http://www.redalyc.org/articulo.oa?id=62046829020 How to cite Complete issue Scientific Information System More information about this article Network of Scientific Journals from Latin America, the Caribbean, Spain and Portugal Journal's homepage in redalyc.org Non-profit academic project, developed under the open access initiative Vol. 15, No. 2 (2016) 543-551 Revista Mexicana de Ingeniería Química CONTENIDO TWO MODELS OF ELECTRICAL IMPEDANCE FOR ELECTRODES WITH TAP WATER ANDVolumen THEIR 8, número CAPABILITY 3, 2009 / Volume TO 8, RECORD number 3, GAS2009 VOLUME FRACTION DOS MODELOS DE IMPEDANCIA ELECTRICA´ PARA ELECTRODOS CON AGUA POTABLE Y SU CAPACIDAD DE REPRESENTAR LA FRACCION´ VOLUMEN DE 213 Derivation and application of the Stefan-MaxwellGAS equations * (Desarrollo y aplicaciónJ.C. de Rodr las ecuaciones´ıguez-Sierra de Stefan-Maxwell) and A. Soria Departamento de Ingenier´ıade Procesos e Hidr´aulica.Divisi´onCBI, Universidad Aut´onomaMetropolitana-Iztapalapa. San Stephen Whitaker Rafael Atlixco No. 186 Col. Vicentina, CP 09340 Cd. de M´exico,M´exico. Received May 24, 2016; Accepted July 5, 2016 Biotecnología / Biotechnology Abstract 245 Modelado de la biodegradación en biorreactores de lodos de hidrocarburos totales del petróleo Bubble columns are devices for simultaneous two-phase or three-phase flows. -
The Radial Electric Field Excited Circular Disk Piezoceramic Acoustic Resonator and Its Properties
sensors Article The Radial Electric Field Excited Circular Disk Piezoceramic Acoustic Resonator and Its Properties Andrey Teplykh * , Boris Zaitsev , Alexander Semyonov and Irina Borodina Kotel’nikov Institute of Radio Engineering and Electronics of RAS, Saratov Branch, 410019 Saratov, Russia; [email protected] (B.Z.); [email protected] (A.S.); [email protected] (I.B.) * Correspondence: [email protected]; Tel.: +7-8452-272401 Abstract: A new type of piezoceramic acoustic resonator in the form of a circular disk with a radial exciting electric field is presented. The advantage of this type of resonator is the localization of the electrodes at one end of the disk, which leaves the second end free for the contact of the piezoelectric material with the surrounding medium. This makes it possible to use such a resonator as a sensor base for analyzing the properties of this medium. The problem of exciting such a resonator by an electric field of a given frequency is solved using a two-dimensional finite element method. The method for solving the inverse problem for determining the characteristics of a piezomaterial from the broadband frequency dependence of the electrical impedance of a single resonator is proposed. The acoustic and electric field inside the resonator is calculated, and it is shown that this location of electrodes makes it possible to excite radial, flexural, and thickness extensional modes of disk oscillations. The dependences of the frequencies of parallel and series resonances, the quality factor, and the electromechanical coupling coefficient on the size of the electrodes and the gap between them are calculated. -
Simulating Twistronics in Acoustic Metamaterials
Simulating twistronics in acoustic metamaterials S. Minhal Gardezi,1 Harris Pirie,2 Stephen Carr,3 William Dorrell,2 and Jennifer E. Hoffman1, 2, ∗ 1School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, 02138, USA 2Department of Physics, Harvard University, Cambridge, MA, 02138, USA 3Brown Theoretical Physics Center and Department of Physics, Brown University, Providence, RI, 02912-1843, USA (Dated: March 24, 2021) Twisted van der Waals (vdW) heterostructures have recently emerged as a tunable platform for studying correlated electrons. However, these materials require laborious and expensive effort for both theoretical and experimental exploration. Here we numerically simulate twistronic behavior in acoustic metamaterials composed of interconnected air cavities in two stacked steel plates. Our classical analog of twisted bilayer graphene perfectly replicates the band structures of its quantum counterpart, including mode localization at a magic angle of 1:12◦. By tuning the thickness of the interlayer membrane, we reach a regime of strong interlayer tunneling where the acoustic magic angle appears as high as 6:01◦, equivalent to applying 130 GPa to twisted bilayer graphene. In this regime, the localized modes are over five times closer together than at 1:12◦, increasing the strength of any emergent non-linear acoustic couplings. INTRODUCTION cate, acoustic metamaterials have straightforward gov- erning equations, continuously tunable properties, fast 1 Van der Waals (vdW) heterostructures host a di- build times, and inexpensive characterization tools, mak- verse set of useful emergent properties that can be cus- ing them attractive testbeds to rapidly explore their tomized by varying the stacking configuration of sheets quantum counterparts. Sound waves in an acoustic meta- of two-dimensional (2D) materials, such as graphene, material can be reshaped to mimic the collective mo- other xenes, or transition-metal dichalcogenides [1{4]. -
Oct. 30, 1923. 1,472,583 W
Oct. 30, 1923. 1,472,583 W. G. CADY . METHOD OF MAINTAINING ELECTRIC CURRENTS OF CONSTANT FREQUENCY Filed May 28. 1921 Patented Oct. 30, 1923. 1,472,583 UNITED STATES PATENT OFFICE, WALTER GUYTON CADY, OF MIDDLETowN, connECTICUT. METHOD OF MAINTAINING ELECTRIC CURRENTS OF CONSTANT FREQUENCY, To all whom it may concern:Application filed May 28, 1921. Serial No. 473,434. REISSUED Be it known that I, WALTER G. CADY, a tric resonator that I take advantage of for citizen of the United States of America, my present purpose are-first: that prop residing at Middletown, in the county of erty by virtue of which such a resonator, 5 Middlesex, State of Connecticut, have in whose vibrations are maintained by im vented certain new and useful Improve pulses; received from one electric circuit, ments in Method of Maintaining Electric may be used to transmit energy in the form B) Currents of Constant Frequency, of which of an alternating current into another cir the following is a full, clear, and exact de cuit; second, that property which it posses 0 scription. ses of modifying by its reactions the alter The invention which forms the subject nating current of a particular frequency or of my present application for Letters Patent frequencies flowing to it; and third, the fact that the effective capacity of the resonator andis an maintainingimprovement alternatingin the art ofcurrents producing of depends, in a manner which will more fully 5 constant frequency. It is well known that hereinafter appear, upon the frequency of heretofore the development of such currents the current in the circuit with which it may to any very high degree of precision has be connected. -
Alternating Current Principles
Basic Electrical Theory Power Principles and Phase Angle PJM State & Member Training Dept. PJM©2014 10/24/2013 Objectives • At the end of this presentation the learner will be able to; • Identify the characteristics of Sine Waves • Discuss the principles of AC Voltage, Current, and Phase Relations • Compute the Energy and Power on AC Systems • Identify Three-Phase Power and its configurations PJM©2014 10/24/2013 Sine Waves PJM©2014 10/24/2013 Sine Waves • Generator operation is based on the principles of electromagnetic induction which states: When a conductor moves, cuts, or passes through a magnetic field, or vice versa, a voltage is induced in the conductor • When a generator shaft rotates, a conductor loop is forced through a magnetic field inducing a voltage PJM©2014 10/24/2013 Sine Waves • The magnitude of the induced voltage is dependant upon: • Strength of the magnetic field • Position of the conductor loop in reference to the magnetic lines of force • As the conductor rotates through the magnetic field, the shape produced by the changing magnitude of the voltage is a sine wave • http://micro.magnet.fsu.edu/electromag/java/generator/ac.html PJM©2014 10/24/2013 Sine Waves PJM©2014 10/24/2013 Sine Waves RMS PJM©2014 10/24/2013 Sine Waves • A cycle is the part of a sine wave that does not repeat or duplicate itself • A period (T) is the time required to complete one cycle • Frequency (f) is the rate at which cycles are produced • Frequency is measured in hertz (Hz), One hertz equals one cycle per second PJM©2014 10/24/2013 Sine Waves -
Advanced High-Frequency Measurement Techniques for Electrical and Biological Characterization in CMOS
Advanced High-Frequency Measurement Techniques for Electrical and Biological Characterization in CMOS Jun-Chau Chien Ali Niknejad Electrical Engineering and Computer Sciences University of California at Berkeley Technical Report No. UCB/EECS-2017-9 http://www2.eecs.berkeley.edu/Pubs/TechRpts/2017/EECS-2017-9.html May 1, 2017 Copyright © 2017, by the author(s). All rights reserved. Permission to make digital or hard copies of all or part of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. To copy otherwise, to republish, to post on servers or to redistribute to lists, requires prior specific permission. Advanced High-Frequency Measurement Techniques for Electrical and Biological Characterization in CMOS by Jun-Chau Chien A dissertation submitted in partial satisfaction of the requirements for the degree of Doctor of Philosophy in Engineering – Electrical Engineering and Computer Sciences in the Graduate Division of the University of California, Berkeley Committee in charge: Professor Ali M. Niknejad, Chair Professor Jan M. Rabaey Professor Liwei Lin Spring 2015 Advanced High-Frequency Measurement Techniques for Electrical and Biological Characterization in CMOS Copyright © 2015 by Jun-Chau Chien 1 Abstract Advanced High-Frequency Measurement Techniques for Electrical and Biological Characterization in CMOS by Jun-Chau Chien Doctor of Philosophy in Electrical Engineering and Computer Science University of California, Berkeley Professor Ali M. Niknejad, Chair Precision measurements play crucial roles in science, biology, and engineering. In particular, current trends in high-frequency circuit and system designs put extraordinary demands on accurate device characterization and modeling. -
Recent Advances in Acoustic Metamaterials for Simultaneous Sound Attenuation and Air Ventilation Performances
Preprints (www.preprints.org) | NOT PEER-REVIEWED | Posted: 27 July 2020 doi:10.20944/preprints202007.0521.v2 Peer-reviewed version available at Crystals 2020, 10, 686; doi:10.3390/cryst10080686 Review Recent advances in acoustic metamaterials for simultaneous sound attenuation and air ventilation performances Sanjay Kumar1,* and Heow Pueh Lee1 1 Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117575, Singapore; [email protected] * Correspondence: [email protected] (S.K.); [email protected] (H.P.Lee) Abstract: In the past two decades, acoustic metamaterials have garnered much attention owing to their unique functional characteristics, which is difficult to be found in naturally available materials. The acoustic metamaterials have demonstrated to exhibit excellent acoustical characteristics that paved a new pathway for researchers to develop effective solutions for a wide variety of multifunctional applications such as low-frequency sound attenuation, sound wave manipulation, energy harvesting, acoustic focusing, acoustic cloaking, biomedical acoustics, and topological acoustics. This review provides an update on the acoustic metamaterials' recent progress for simultaneous sound attenuation and air ventilation performances. Several variants of acoustic metamaterials, such as locally resonant structures, space-coiling, holey and labyrinthine metamaterials, and Fano resonant materials, are discussed briefly. Finally, the current challenges and future outlook in this emerging field