| Model for Ultrafast Carrier Scattering in Semiconductors |
14 Nov 2012 |
20 pages |
| Authors:
Danhong Huang; David Cardimona; AIR FORCE RESEARCH LAB KIRTLAND AFB NM SPACE VEHICLES DIRECTORATE
|
 | One of the major products the AF is looking for is a lightweight, reconfigurable electro-optic sensor system. Towards that end, we are investigating the possibilities of incorporating a protection layer, an optical signal amplification layer, a detection layer, a solid-state cooling layer, and a readout electronics layer all monolithically integrated within a single pixel of a semiconductor focal plane array (for vast reductions in size and weight). When completed, the ... |
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| Micro-Composite Fabrication via Field-Aided Laminar Composite (FALCom) Processing |
Sep 2012 |
30 pages |
| Authors:
Jr Holmes Larry R; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD WEAPONS AND MATERIALS RESEARCH DIRECTORATE
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| A novel composite fabrication process is used to create multi-functional micro-composites, which can be tailored for specific end-use applications. The Field-Aided Laminar Composite (FALCom) process uses specifically focused electric fields to align nano- to micro-sized particles into chain-like structures, which are referred to as pseudo-fibers. These pseudo-fibers are then immediately frozen into place by the laser curing of the photopolymer matrix. The pseudo-fibers are arranged by design, and are used ... |
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| Modeling and Design of Mixed-coherence Optical Stacks |
Sep 2012 |
24 pages |
| Authors:
William Beck; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
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| A Mathematica-based program for designing layered optical structures is described that can compute the optical properties at an arbitrary angle of incidence for stacks containing anisotropic and dispersive materials as well as stacks that contain a mixture of coherent and incoherent sections. The program can be used to calculate the properties of a fully specified optical stack or can be used to optimize some property of the stack by varying ... |
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| Measuring the Electro-Optic Coefficients of Bulk-poled Polymers |
Sep 2012 |
20 pages |
| Authors:
Robert C Hoffman; Joshua A Orlicki; George R Martin; Robert Lambeth; MyVan Baranoski; ARMY RESEARCH LAB ADELPHI MD
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| This report describes the construction of an optical test system to measure the electro-optic coefficients of poled polymers directly. The poling process in polymers is the spontaneous orientation of the dissolved dye molecule, the chromophore, in the presence of an applied electric field. This spontaneous orientation confers upon the poled polymer a variety of useful optical effects, the linear electro-optic effect being chief among them. The optical test system measures ... |
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| Calculation of Impedance Matrix Inner Integral to Prescribed Precision for the Magnetic Field Integral Equation |
19 Jul 2012 |
109 pages |
| Authors:
John S Asvestas; Dennis W Richardson; Oliver E Allen; NAVAL AIR WARFARE CENTER AIRCRAFT DIV PATUXENT RIVER MD
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| The Method of Moments (MoM) is a powerful computational electromagnetics method for analyzing antennas in situ. In a previous report, we presented a new method for evaluating the inner integral of the impedance matrix element in the traditional Rao-Wilton-Glisson formulation of MoM for the electric field integral equation. In this report, we extend our method to the magnetic field integral equation. We show how, in this case, the inner integral ... |
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| Ferroelectric Domain Scaling and Switching in Ultrathin BiFeO3 Films Deposited on Vicinal Substrates |
25 May 2012 |
11 pages |
| Authors:
Vilas Shelke; Dipanjan Mazumdar; Stephen Jesse; Sergei Kalinin; Arthur Baddorf; Arunava Gupta; ALABAMA UNIV TUSCALOOSA CENTER FOR MATERIALS FOR INFORMATION AND TECHNOLOGY
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| We report on electrically switchable polarization and ferroelectric domain scaling over a thickness range of 5-100 nm in BiFeO3 films deposited on [110] vicinal substrates. The BiFeO3 films of variable thickness were deposited with SrRuO3 bottom layer using the pulsed laser deposition technique. The domains are engineered into preferentially oriented patterns due to substrate vicinality along the [110] direction. The domain width scales closely with the square root of film ... |
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| Theoretical Transport Studies of Non-equilibrium Carriers Driven by High Electric Fields |
25 Apr 2012 |
22 pages |
| Authors:
Alden Astwood; V M Kenkre; NEW MEXICO UNIV ALBUQUERQUE
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| This work examines quantum transport in nanowires with several different formalisms. The Boltzmann equation based theory of Lyo and Huang is able to incorporate many different kinds of scattering and make interesting predictions but found absent in it a simple way of providing physical understanding of its effects. The STM theory of Kenkre, Biscarini, and Bustamante incorporates incoherent scattering in a much simpler way, but difficulties arise when the motion ... |
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| Field Emission of Thermally Grown Carbon Nanostructures on Silicon Carbide |
22 Mar 2012 |
182 pages |
| Authors:
Jonathon M Campbell; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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| CNTs are known to be excellent field emitter due to their unique physical and electrical properties. Because of their semi-metallic nature, CNT do not suffer the thermal runaway found in metallic emitters, and their near one-dimension shape make them an ideal emission sources. CNTs growth by thermal decomposition of silicon carbide does not utilize a catalyst, therefore relatively defect free. One drawback to this method, however is that the CNT ... |
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| Design, Modeling, and Measurement of a Metamaterial Electromagnetic Field Concentrator |
22 Mar 2012 |
243 pages |
| Authors:
Noel A Humber; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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| This document addresses the need to improve the design process for creating an optimized metamaterial. In particular, two challenges are addressed: creating an electromagnetic concentrator and optimizing the design of metamaterial used to create the electromagnetic concentrator. The first challenge is addressed by developing an electromagnetic field concentrator from a design of concentric geometric shapes. The material forming the concentrator is derived from the application of transformation optics. The resulting ... |
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| Positron Lifetime Modulation by Electric Field Induced Positronium Formation on a Gold Surface |
22 Mar 2012 |
155 pages |
| Authors:
Daniel J Higgins; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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| The purpose of this project is to study the lifetime and annihilation mode of positrons, the antimatter counterpart to electrons, and the formation rate of positronium on a gold surface modified by gold nanoparticles under the influence of radial electric fields measured using two independent systems. The positron annihilation photon pair/triplet spectroscopy system uses a sodium iodide ring detector segmented into six detection regions providing rough position sensitivity to measure ... |
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| Geospace Plasma Dynamics Laboratory Annual Task Report (FY11) |
01 Mar 2012 |
14 pages |
| Authors:
Daniel Ober; AIR FORCE RESEARCH LAB KIRTLAND AFB NM SPACE VEHICLES DIRECTORATE
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| This annual report provides a summary of progress made during FY11 on AFOSR task titled Geospace Plasma Dynamics. The goal of this research effort is to develop a detailed knowledge of the space environment by analyzing satellite data and developing the theories needed to explain the observations. In this way we hope to improve our capability to predict the state of the space environment. This effort includes 4 basic research ... |
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| Development of a Radar-Frequency Metamaterial Measurement and Characterization Apparatus |
Mar 2012 |
215 pages |
| Authors:
Stephen I Faris; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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| The overall purpose of this research was to design, build, and test an apparatus for the measurement and characterization of radar-frequency metamaterial performance in the S-band through Ku-band (2-18 GHz). Measurement and characterization is vital to metamaterial taxonomy and ultimately vital to metamaterial definitions. Thus, the current lack of clarity in metamaterial definitions has served as the primary motivation for pursuing a method for taxonomy and thus, this apparatus. The ... |
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| Single-cycle Optical Pulses and Isolated Attosecond Pulse Generation |
29 Feb 2012 |
41 pages |
| Authors:
Franz X Kaertner; MASSACHUSETTS INST OF TECH CAMBRIDGE
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| The MIT Single-Cycle Pulse and Isolated Attosecond Pulse Generation Program enabled to demonstrate, for the first time, a novel pulse synthesis technology based on ultrabroadband multi-color OPCPAs and explore the generation and control of isolated attosecond XUV pulses using the synthesized pulses. We developed several relevant ultrafast laser technologies and attosecond measurement systems, such as picosecond cryo-cooled Yb:YAG pump laser amplifiers, 2D and 4DSI pulse characterization techniques, optical balanced cross-correlator, ... |
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| Near-Field Propagation of Sub-Nanosecond Electric Pulses into Amorphous Masses |
01 Feb 2012 |
52 pages |
| Authors:
Shu Xiao; Karl H Schoenbach; OLD DOMINION UNIV NORFOLK VA FRANK REIDY RESEARCH CENTER FOR BIOELECTRICS
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| The project, Near-Field Propagation of Sub-Nanosecond Electric Pulses into Amorphous Masses , deals with the propagation of subnanosecond pulsed radiation in the near field region and its use in probing inhomogeneities in dielectrics. It also explores the possibility of changing the physical structure of lossy dielectrics by using very intense pulses. A subnanosecond high voltage pulse generator was constructed, which is able to deliver 150 ps (FWHM) pulses with 100 ... |
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| Numerical Modeling of Pulsed Electrical Discharges for High-Speed Flow Control |
Feb 2012 |
175 pages |
| Authors:
Jonathan Poggie; AIR FORCE RESEARCH LAB WRIGHT-PATTERSON AFB OH AIR VEHICLES DIRECTORATE
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| This report describes work carried out on numerical modeling of flow control devices based on pulsed electrical discharges. Given the lack of flow control options in the high-speed regime, there is strong interest in developing such devices for control of laminar-turbulent transition, turbulence, engine unstart, and inlet shock train stability. Pulsed electrical discharge actuators offer the features of rapid actuation, low profile, and low mean power consumption. Under this project, ... |
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| Coupling Issues Associated with Electro-Magnetic Vulnerability (EMV) Testing of Vehicles Over Ground |
Jan 2012 |
17 pages |
| Authors:
T H Shumpert; M L Waller; S H Wong; R W Scharstein; REDSTONE TEST CENTER REDSTONE ARSENAL AL
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| Electromagnetic Vulnerability (EMV) testing of ground vehicles and helicopters is (by necessity) performed in the immediate presence of ground surfaces (natural earth, asphalt, concrete, ship decks, and other finitely conducting grounds). The impact of the nature of these grounds on the EM coupling to the various vehicles being tested is the focus of this work. As one approach to addressing these issues quantitatively, personnel at Redstone Test Center Electromagnetic Environmental ... |
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| Plasmon Lasers: Coherent Light Source at Molecular Scales |
Jan 2012 |
22 pages |
| Authors:
Ren-Min Ma; Rupert F Oulton; Volker J Sorger; Xiang Zhang; CALIFORNIA UNIV BERKELEY NANOSCALE SCIENCE AND ENGINEERING CENTER
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| Plasmon lasers are a new class of coherent optical frequency electromagnetic wave amplifiers that deliver intense coherent and directional surface plasmons well below the diffraction barrier. The strongly confined electric fields in plasmon lasers can enhance significantly light-matter interactions and bring fundamentally new capabilities to bio-sensing, data storage photolithography and optical communications. |
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| Effect of Electric Fields of the Reaction Rates in Shock Initiating and Detonating Solid Explosives |
Jan 2012 |
6 pages |
| Authors:
Craig M Tarver; LAWRENCE LIVERMORE NATIONAL LAB CA
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| The presence of a strong electric field has been demonstrated to effect the shock initiation and detonation wave propagation of solid high explosives. Several mechanisms have been proposed to explain the observed increased shock sensitivity, increased detonation velocity, and decreased failure diameter of certain explosives. The most likely chemical mechanism is postulated to be the excitation of some of the explosive molecules and/or intermediate reaction products to higher energy electronic ... |
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| Characterization Techniques for a MEMS Electric-Field Sensor in Vacuum |
Jan 2012 |
13 pages |
| Authors:
Simon Ghionea; David Hull; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
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| An accurate calibration of an electric-field sensor is difficult to carry out due to challenges involved in generating a uniform electric field over the sensor volume. Additionally, capacitive coupling between the field source and the sensors and related instrumentation tends to distort the measured field further. Sensor characterization includes not only calibration, but also determination of the frequency response (both magnitude and phase), noise power spectral density, dynamic range, and ... |
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| Multi-Scale Modeling of Novel Hall Thrusters: Understanding Physics of CHT and DCF Thrusters |
30 Dec 2011 |
34 pages |
| Authors:
Michael Keidar; GEORGE WASHINGTON UNIV WASHINGTON DC
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| In order to simulate the magnetized plasma thruster devices (such as CHT, DCF etc) we have developed a multi-scale numerical code that is based on coupling of a PIC/MCC analysis of neutrals and ions in a general 2D domain (or 3D) and a 1D kinetic full PIC treatment of electrons along magnetic fields. The implementation of such a two-way coupling allows calculation of the electron transport in the real physical ... |
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| Electromagnetic Induction E-Sensor for Underwater UXO Detection |
Dec 2011 |
34 pages |
| Authors:
Yongming Zhang; QUASAR FEDERAL SYSTEMS INC SAN DIEGO CA
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| QUASAR Federal Systems (QFS) endeavored to adapt its innovative underwater capacitive electrode electric field (E) sensors for use in detection of Unexploded Ordnance (UXO) objects in seawater. The system was based around an existing Time Domain Electromagnetic (TDEM) sensor, in which a pulsed magnetic (B) field induces eddy currents in the target. The eddy currents produce a secondary B-field, which in a conducting medium can be detected with either E-sensors ... |
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| Design and Installation of a Field Ionization Test Chamber for Ion Thrusters |
Dec 2011 |
93 pages |
| Authors:
Paul W Camp; NAVAL POSTGRADUATE SCHOOL MONTEREY CA
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| The utilization of carbon nanotube arrays for field ionization in ion thrusters allows for a substantial reduction in thruster size and weight. The availability of miniature ion thrusters may enable the development of a suitable propulsion system for nano- and picosatellites, and can realize substantial weight, volume, and cost savings in existing satellite platforms. This research focuses on the design of a field ionization test chamber that can be used ... |
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| Resonant Energy Transfer in a System of Cold Trapped Molecules |
17 Oct 2011 |
4 pages |
| Authors:
Heather Lewandowski; COLORADO UNIV AT BOULDER
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| We have four main results from the research supported by the AFOSR over the last three years. They are (1) a new mode of Stark deceleration to increase the energy resolution of the resulting molecular beam, (2) theoretical investigation of resonant collisional quenching of NH molecules, (3) measurement of electric field affected collisions between cold ammonia molecules and ultracold rubidium atoms, (4) creation and deceleration of velocity controlled beams of ... |
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| Studies of the Origins of the Kuroshio and Mindanao Currents with EM-APEX Floats and HPIES |
30 Sep 2011 |
6 pages |
| Authors:
Thomas B Sanford; WASHINGTON UNIV SEATTLE
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| Improving observations and understanding of major oceanographic features and phenomena. We emphasize motionally induced electric fields for measuring ocean velocities. Specific goals for OKMC include: Observe Bt and Bc velocity around Ren-Chieh Lien s upper ocean ADCP moorings with HEF (Horizontal E-Field) and PIES (Pressure and Inverted Echo Sounder) merged into 5 HPIES under the Kuroshio north of Luzon Observe velocity and density structure of NEC with 10 EM-APEX floats ... |
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| Interactions of Low-Energy Ions and Electrons with Bose-Einstein Condensates |
13 Sep 2011 |
4 pages |
| Authors:
Georg A Raithel; MICHIGAN UNIV ANN ARBOR
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| A significant amount of theoretical work on dilute atomic BEC has focused on how condensates interact with ultra-cold charged impurities. To enable experimental studies, we have constructed a BEC setup embedded in a Faraday cage suitable to compensate stray electric fields at the BEC location to levels below about 0.1 mV/cm. Using RF-induced evaporative cooling and evaporative cooling by surface adsorption we prepare atom clouds down to one microKelvin temperature. ... |
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| Analysis of Transient Electromagnetic Scattering from an Overfilled Cavity Embedded in an Impedance Ground Plane |
Sep 2011 |
138 pages |
| Authors:
Robert S Callihan; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING AND MANAGEMENT
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| We consider the transient, or time-domain, scattering problem of a two-dimensional overfilled cavity embedded in an impedance ground plane. This problem is a significant advancement from previous work where more simplified boundary conditions were used, which can limit the number of applications. This research supports a wide range of military applications such as the study of cavity-like structures on aircraft and vehicles. More importantly, this research helps detect the biggest ... |
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| Millimeter-wave Interferometric Sensing |
Sep 2011 |
20 pages |
| Authors:
Charles R Dietlein; Amir Zaghloul; David A Wikner; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
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| Millimeter-wave sensing systems designed for imaging almost always produce inferior images compared to their infrared and visible wavelength counterparts for a variety of fundamental reasons. These reasons include low detector/pixel count, poor signal-to-noise ratio, artifacts introduced by illumination, and issues arising from calibration or scanning schemes. This research effort is intended to address the issue of low-detector-count focal-plane arrays (FPA). Radio astronomers have dealt with this issue for many decades ... |
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| Single-cycle Pulse Synthesis by Coherent Superposition of Ultra-broadband Optical Parametric Amplifiers |
AUG 2011 |
45 pages |
| Authors:
Giulio Cerullo; POLITECNICO DI MILANO (ITALY)
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| Ultrafast optical science has experienced major breakthroughs in the last years, driven by two main accomplishments: (i) generation of light pulses with duration of just a few cycles of the optical carrier wave; (ii) control of the carrier-envelope phase (CEP) of light pulses, enabling the production of optical waveforms with reproducible electric field. The generation of extremely short light pulses with controlled CEP allows exploring new frontiers of light-matter interaction, ... |
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| 2011 In-Water Testing of Aquatic Nuisance Species Dispersal Barriers IIA and IIB with Increased Voltage and Frequency Operating Parameters |
Aug 2011 |
143 pages |
| Authors:
Michael K McInerney; Brianna S Aubin; Jonathan C Trovillion; Carey L Baxter; Ethan T Trovillion; Jr Hock Vincent F; David M Weir; ENGINEER RESEARCH AND DEVELOPMENT CENTER CHAMPAIGN IL CONSTRUCTION ENGINEERING RESEARCH LAB
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| US Army Engineer District - Chicago operates an electric field-based aquatic nuisance species dispersal barrier system in the Chicago Sanitary and Ship Canal (CSSC), Romeoville, IL. The barriers were constructed to prevent the movement of invasive species, such as Asian big-head carp (Hypophthalmichthys nobilis) and silver carp (Hypophthalmichthys molitrix) between the Mississippi River and Great Lakes basins. The objective of this project was to perform a series of in-water tests ... |
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| Growth and Transfer of Graphene for Device Fabrication |
Aug 2011 |
14 pages |
| Authors:
Kevin Hauri; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE/ELECTRONICS AND RADIOFREQUENCY DIV
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| The unique electronic properties of graphene enable the development of field effect transistors with potential for speeds much higher than the existing technology. Diluted methane chemical vapor deposition growth of graphene on a nickel substrate has resulted in potentially useful multilayer graphene layers. These graphene layers were grown on nickel substrates deposited onto silicon (Si)/silicon dioxide (SiO2) wafers by evaporation and sputter methods. The graphene must be transferred from the ... |
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| Fundamental Studies of Electric-Field-Induced Coherent Raman Scattering |
07 JUN 2011 |
13 pages |
| Authors:
Tsuyohito Ito; OSAKA UNIV (JAPAN)
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| A rather novel method has been studied, referred to here as electric-field-induced coherent Raman scattering (E-CRS). Two beams of laser pulses of frequencies, whose energy difference matches to the Raman transition, produce an infrared (IR) coherent beam corresponding to the Raman transition energy in the presence of a direct-current (dc) electric field. The IR light may be considered as an anti-Stokes wave generated by the electric fields of two laser ... |
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| Low-Voltage Electrowetting on a Lipid Bilayer Formed on Hafnium Oxide |
01 Jun 2011 |
12 pages |
| Authors:
Ingrid F Guha; Jakub Kedzierski; Behrouz Abedian; MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
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| We present a class of electrowetting systems in which lipid bilayers function as reversibly wettable dielectrics, eliminating the need for solid organic dielectrics (e.g. fluoropolymers) in electrowetting systems. These bilayers form spontaneously between water drops and hafnium oxide surfaces in oil and can withstand high electric fields, enabling high contact angle changes at unprecedentedly low voltages. We demonstrate that under well-defined conditions, these electrowetting systems are virtually free of contact ... |
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| Carbon Nanotube Field Emission Arrays |
JUN 2011 |
157 pages |
| Authors:
Benjamin L. Crossley; AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH GRADUATE SCHOOL OF ENGINEERING AND MANAGEMENT
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| This effort exploits the unique physical and electrical characteristics of carbon nanotubes (CNTs) for field emission applications. Carbon nanotube field emission devices are designed, fabricated, and tested. Two reliable CNT synthesis methods, microwave plasma enhanced chemical vapor deposition (MPE-CVD) and thermal chemical vapor deposition (T-CVD), are developed. The physical properties of the resulting CNTs are analyzed using Raman spectroscopy and Scanning electron microscopy (SEM) and then tested for field emission ... |
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| Structural Damping and Health Monitoring Enhancement via Multifunctional Carbon Nanotube-Based Composites Tailoring |
23 APR 2011 |
23 pages |
| Authors:
Charles E. Bakis; Kon-Well Wang; PENNSYLVANIA STATE UNIV UNIVERSITY PARK
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| Damping enhancement can lead to significant enhancement of mission capability in Army structures such as those used in rotorcraft, for instance. The objective of this investigation is to explore and understand the fundamental mechanisms of damping provided by carbon nanotubes (CNTs) in polymer-based materials such as those used to fabricate fiber composites, and to use this new understanding to explore further enhancements in damping. In addition, the feasibility of using ... |
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| Limits to Maximum Absorption Length in Waveguide Photodiodes |
13 Apr 2011 |
12 pages |
| Authors:
Shannon M Madison; Jonathan Klamkin; Douglas C Oakley; Antonio Napoleone; Jason J Plant; Paul W Juodawlkis; MASSACHUSETTS INST OF TECH LEXINGTON LINCOLN LAB
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| The maximum photocurrent, power dissipation, and Iinearity of waveguide photodiodes are limited by the length over which the input optical power is absorbed. This absorption length is determined by the absorption coefficient of the absorbing layer material (a0), the optical confinement factor (r), and the excess optical loss (ai). In this work, we analyze the fundamental limits to maximizing the absorption length and demonstrate a new waveguide photodiode structure that ... |
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| Spatio-temporal Theory of Lasing Action in Optically-Pumped Rotationally Excited Molecular Gases |
11 Apr 2011 |
19 pages |
| Authors:
Song-Liang Chua; Christine A Caccamise; Dane J Phillips; John D Joannopoulos; Marin Soljacic; Henry O Everitt; Jorge Bravo-Abad; MASSACHUSETTS INST OF TECH CAMBRIDGE DEPT OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCE
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| We investigate laser emission from optically-pumped rotationally excited molecular gases confined in a metallic cavity. To this end we have developed a theoretical framework able to accurately describe both in the spatial and temporal domains, the molecular collisional and diffusion processes characterizing the operation of this class of lasers. The effect on the main lasing features of the spatial variation of the electric field intensity and the ohmic losses associated ... |
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| The Strength of PIN-PMN-PT Single Crystals under Bending with a Longitudinal Electric Field |
06 APR 2011 |
9 pages |
| Authors:
P. Zhao; S. Goljahi; W. Dong; T. Wu; P. Finkel; R. Sahul; K. Snook; J. Luo; W. Hackenberger; C. S. Lynch; NAVAL UNDERSEA WARFARE CENTER DIV NEWPORT RI
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| The effect of an electric field on the bending behavior of [001] oriented and poled relaxor Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) single crystals was measured using a four point bending apparatus with a longitudinal electric field applied to the bar during bending. The surface finish and electric field amplitude were observed to affect the bending strength. Polished surfaces improve the tensile strength, while also polishing the edges resulted in a significantly larger increase ... |
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| Low Cost, High Performance Avalanche Photodiodes for Enabling High Sensitivity Bio-fluorescence Detection (First Year of a Two-year Program) |
APR 2011 |
24 pages |
| Authors:
Anand V. Sampath; Michael Wraback; ARMY RESEARCH LAB ADELPHI MD SENSORS AND ELECTRON DEVICES DIRECTORATE
|
| In this report we discuss the modeling, fabrication, and characterization of novel ultraviolet separate absorption and multiplication avalanche photodiodes (SAM-APDs) employing a gallium nitride (GaN) absorption region and a 4H-silicon carbide (SiC) multiplication region. We demonstrate the importance of polarization induced interface charge on the electric field distribution within the quantum efficiency of this device. In addition, we show that the total interface charge can be controlled for optimal detector ... |
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| Electro-Thermo-Mechanical Homogenization of Ferroelectric Atomistic Medium |
23 MAR 2011 |
39 pages |
| Authors:
Jacob Fish; RENSSELAER POLYTECHNIC INST TROY NY
|
| Two-scale continuum equations are derived for heterogeneous continua with full nonlinear electromechanical coupling using nonlinear mathematical homogenization theory. The resulting coarse-scale electromechanical continuum equations are free of coarse-scale constitutive equations. The unit cell (or Representative Volume Element) is subjected to the overall mechanical and electric fields extracted from the solution of the coarse-scale problem and is solved for arbitrary constitutive equations of fine-scale constituents. The proposed method can be applied ... |
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| Near-field Examination of Perovskite-based Superlenses and Superlens-enhanced Probe-object Coupling |
22 Mar 2011 |
10 pages |
| Authors:
S C Kehr; Y M Liu; L W Martin; P Yu; M Gajek; S Yang; C Yang; M T Wenzel; R Jacob; H von Ribbeck; CALIFORNIA UNIV BERKELEY NANOSCALE SCIENCE AND ENGINEERING CENTER
|
| A planar slab of negative-index material works as a superlens with sub-diffraction-limited resolution, as propagating waves are focused and, moreover, evanescent waves are reconstructed in the image plane. Here we demonstrate a superlens for electric evanescent fields with low losses using perovskites in the mid-infrared regime. The combination of nearfield microscopy with a tunable free-electron laser allows us to address precisely the polariton modes, which are critical for super-resolution imaging. ... |
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| Manipulating Rydberg Electrons With Strong Electric-Field Pulses: Applications to THz Field Detection and Decoherence Suppression |
25 Feb 2011 |
8 pages |
| Authors:
Robert R Jones; VIRGINIA UNIV CHARLOTTESVILLE RECTOR AND VISTORS OF THE UNIVERSITY OF VIRGINIA
|
| Our primary research effort during the funding period focused on the exploration and control of coherent time-dependent electronic interactions within and between atoms. Specifically, we considered the behavior of Rydberg atoms in which one electron is very highly-excited, residing in a state of large principal quantum number, n. Such highly-excited Rydberg electrons are extremely sensitive to electric fields due, for example, to neighboring atoms or external radiation at frequencies from ... |
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| AlGaN/GaN High Electron Mobility Transistor Degradation Under On- and Off-State Stress |
Jan 2011 |
6 pages |
| Authors:
E A Douglas; C Y Chang; D J Cheney; B P Gila; C F Lo; Liu Lu; R Holzworth; P Whiting; K Jones; G D Via; FLORIDA UNIV GAINESVILLE DEPT OF MATERIALS SCIENCE AND ENGINEERING
|
| AlGaN/GaN High Electron Mobility Transistors (HEMTs) with various gate lengths have been stepstressed under both on- and off-state conditions. On-state, high power stress tests were performed on 0.17 lm gate length HEMTs and a single 5 lm spaced TLM pattern. Significant degradation of the submicron HEMTs as compared to the excellent stability of the TLM patterns under the same stress conditions reveal that the Schottky contact is the source of ... |
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| Fundamental Issues in Space Electronics Reliability: Negative Bias Temperature Instability |
Dec 2010 |
88 pages |
| Authors:
Jesse K Mee; NEW MEXICO UNIV ALBUQUERQUE
|
| Negative Bias Temperature Instability (NBTI) in silicon based metal-oxide-semiconductor- field-effect-transistors (MOSFETs) has been recognized as a critical reliability issue for advanced space qualified electronics. The phenomenon manifests itself as a modification of threshold voltage (Vth) resulting in degraded signal timing paths, and ultimately circuit failure. Despite the obvious importance of the issue, a standard measurement protocol has yet to be determined. This is a consequence of a large amount of ... |
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| Measurement and Model Predicted Corrosion Related Magnetic Signature: Applied on CFAV Quest |
Oct 2010 |
34 pages |
| Authors:
Marius Birsan; DEFENCE RESEARCH AND DEVELOPMENT ATLANTIC DARTMOUTH (CANADA)
|
| In simple terms the corrosion related magnetic (CRM) field arises due to the flow of corrosion currents through the sea water. This current density has many sources with one of the most prominent being the currents that arise due to the corrosion of the metal work of the ship. Various corrosion countermeasures, for example an impressed current cathodic protection (ICCP) system, also directly affect the current density and hence an ... |
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| Ordered Magnetic Nanoparticle Arrays on Tunable Substrates for RF Applications |
24 SEP 2010 |
24 pages |
| Authors:
Hariharan Srikanth; UNIVERSITY OF SOUTH FLORIDA TAMPA
|
| This research project led to fabrication of tunable multilayer oxide structures based on Barium Strontium Titanate (BST) and Barium Hexaferrite (BaM) materials, demonstrate tunability of impedance when subject to external electrical and magnetic fields and also explore the fabrication, properties and electromagnetic properties of magnetic oxide nanoparticles. We showed for the first time low-leakage BST/BaM structures grown by PLD that had excellent dual tunability using electric and magnetic fields. The ... |
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| Reverse Gate Bias-Induced Degradation of AlGaN/GaN High Electron Mobility Transistors |
23 Sep 2010 |
5 pages |
| Authors:
Chih-Yang Chang; Travis Anderson; Jennifer Hite; Liu Lu; Chien-Fong Lo; Byung-Hwan Chu; D J Cheney; E A Douglas; B P Gila; F Ren; FLORIDA UNIV GAINESVILLE DEPT OF MATERIALS SCIENCE AND ENGINEERING
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| A threshold reverse bias of 21 V was observed leading to a sharp increase in the gate current of AlGaN/GaN high electron mobility transistors biased at low source-drain voltage (5 V). The gate current increases by one to two orders of magnitude at this bias, corresponding to an electric field strength around 1.8 MV cm 1. The gate current increased by roughly five orders of magnitude after step-stressing the gate ... |
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| Modeling and Direct Electric-Field Measurements of Passively Mode-Locked Quantum-Dot Lasers (Postprint) |
JUL 2010 |
10 pages |
| Authors:
Nicholas G. Usechak; Vassilios Kovanis; Yongchun Xin; Chang-Yi Lin; Luke F. Lester; Daniel J. Kane; NEW MEXICO UNIV ALBUQUERQUE CENTER FOR HIGH TECHNOLOGY MATERIALS
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| A delay differential equation model of a passively mode-locked two-section quantum-dot laser reveals pulse asymmetry that is experimentally confirmed through direct electric-field measurements using frequency-resolved optical gating. This finding indicates that conventional autocorrelators, which obscure the underlying pulse structure due to the symmetry inherent in autocorrelation, are of limited utility in the characterization of these lasers. |
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| Molecular Dynamics Modeling of Ionic Liquids in Electrospray Propulsion |
JUN 2010 |
126 pages |
| Authors:
Nanako Takahashi; MASSACHUSETTS INST OF TECH CAMBRIDGE
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| Micro-propulsion has been studied for many years due to its applications in small-tomedium sized spacecraft for precise satellite attitude control. Electrospray thrusters are promising thrusters built upon the state of the art in micro-technology and with flexible performance in terms of their high efficiency and high specific impulse. One challenge is to investigate in detail the mechanism for ion emission to complement experimental results and understand better how emission occurs ... |
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| Nonlinear Structuring and High-energy Electrons: Role in Ionosphere and in Thunderstorm Atmosphere Processes |
MAY 2010 |
65 pages |
| Authors:
Aleksander V. Gurevich; RUSSIAN ACADEMY OF SCIENCES MOSCOW LEBEDEV INST
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| This report results from a contract tasking P. N. Lebedev Physical Institute as follows: The Project includes five Tasks: 1. The modification of the magnetosphere by the controllable flow of fast electrons coming upwards from the artificially modified ionosphere. Theoretical investigation and the conception of the experimental program. 2. The formation of super-narrow ionosphere structures in ionosphere artificially modified by powerful radio waves in double-resonance conditions. The super-narrow structures serve ... |
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| On the Role of Built-in Electric Fields on the Ignition of Oxide Coated NanoAluminum: Ion Mobility versus Fickian Diffusion |
2010 |
13 pages |
| Authors:
Brian J. Henz; Takumi Hawa; MICHAEL R. ZACHARIAH; ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD
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| Using the classical molecular dynamics method we simulate the mechanochemical behavior of small, core diameter <10 nm oxide coated aluminum nanoparticles. Aluminum nanoparticles with core diameters of approximately 5 and 8 nm are simulated with 1 and 2 nm thick oxide coatings or shells. In addition to thickness the shells are parametrized by varying degrees of crystallinity, density, and atomic ratios in order to study their effect on the ignition ... |
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Reports by Keyword(s)
ELECTRIC FIELDS
