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IEEE Conference on Particle Accelerator

作者： S. Humphries D. Rees Department of Electrical and Computer Engineering University of New Mexico Albuquerque NM USA APT Program Los Alamos National Laboratory Los Alamos NM USA

We have developed an integrated software system, TrakRF, to model electromagnetic fields and charged particle orbits in high-power RF devices. Our primary application is simulation of electron multipactoring near RF vacuum windows for the APT (Accelerator Production of Tritium) program. In this paper we describe features of the codes and initial multipactor calculations for superconducting cavity arrays. The finite-element frequency-domain solver can determine resonant modes in cavities and waveguides. TrakRF directly determines power dissipation and phase shifts in lossy materials. In addition, the program.handles scattered waves in open structures with free-space boundaries based on matched termination layers. TrakRF has advanced particle tracking capabilities to investigate a variety of innovative window designs. The program.can simultaneously apply three independent solutions for electrostatic, magnetostatic and RF fields. The finite-element methods allow an accurate representation of electron collisions with surfaces.

关键词： Radio frequency Finite element methods Software systems Electromagnetic modeling Electromagnetic fields Orbits Application software Particle accelerators Electron accelerators Production

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Analysis of product codes for frequency-hopped spread-spectrum with partial band interference

Analysis of product codes for frequency-hopped spread-spectr...

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MILCOM, Military Communications Conference

作者： T.C. Nolan W.E. Stark Department of Defense graduate fellowship program Focused Research Initiative agreement Ann Arbor MI USA Department of Electrical Engineering and Computer Science University of Michigan Ann Arbor MI USA

A jamming game is considered. A transmitter encodes the data, in a product code (PC), and transmits it in a slow frequency-hopped spread-spectrum (FHSS) system. A hostile jammer attempts to block correct packet reception by adjusting the fraction of the total band in which it distributes the jam power, /spl rho/. Two cases are considered. In the first case, the transmitter declares his strategy and the jammer uses this information to select his best jamming fraction. In the second case, the jammer declares his strategy first and the transmitter uses this information to select his best rates. Results are obtained using asymptotic analysis of a product code using singly extended Reed-Solomon (RS) row and column codes whose size grows large. This asymptotic analysis leads to good choices of the row and column rates for the PC in both cases.

关键词： Product codes Spread spectrum communication Interference Jamming Decoding Error correction codes Frequency shift keying Error correction Reed-Solomon codes Transmitters

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Unification of azo-polymer systems by photo-Induced molecular movement

Unification of azo-polymer systems by photo-Induced molecula...

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Sol-Gel and Polymer Photonic Devices: A Critical Review 1997

作者： Sekkat, Zouheir Knoesen, Andre Knoll, Wolfgang Miller, Robert D. Department of Electrical and Computer Engineering University of California DavisCA95616 United States Max -Planck -Institut Für Polymerforschung Ackermannweg 10 Mainz55128 Germany Frontier Research Program Wako Saitama351-01 Japan IBM Research Center Science and Technology 650 Harry Road San JoseCA95120-6099 United States

We review our recent research in the field of photochromic polymeric structures for optical data storage and nonlinear optics. We unify some of the sub -Themes of azopolymer structures in the light of photo -induced movement of azobenzene molecules. In particular, we discuss photo- induced effects in supramolecular assemblies containing azobenzene molecules (e.g. Langmuir- Blodgett -Kuhn structures and ultrathin silane layers). Reorientation of azobenzenes in these structures will be compared to that observed in spin -cast films. Photoisomerization and photo- induced orientation of azobenzene molecules is also studied at the molecular level by means of azosilane molecules chemisorbed on Silicon Oxide substrates. We establish a correlation between polymer architecture and sub -glass transition temperature (Tg) light- induced molecular movement in high Tg nonlinear optical azo- polyimide polymers. We show that the isomerization reaction itself depends on the polymer molecular structure, and we present evidence of light- induced molecular movement 325 °C below Tg of a rigid NLO azopolyimide polymer containing no flexible connector or tether. © (1997) 2017 SPIE.

关键词： Self assembled monolayers

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A parallel approach to digital holographic reconstruction with twin-image removal

A parallel approach to digital holographic reconstruction wi...

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IEEE Southeastcon

作者： Chihyung Tu J. Gerlach Sung-Chi Chu Ting-Chung Poon Computational Sciences Program Radford University Radford VA USA Department of Mathematics Radford University Radford VA USA Department of Computer Science Radford University Radford VA USA Bradley Department of Electrical Engineering Virginia Polytechnic Institute and State University Blacksburg VA USA

A parallel method developed for reconstructing images from holograms obtained with optical scanning holography is presented. A standard portable message-passing library, MPI or message-passing interface, is used to provide the environment of parallel program.ing. The parallel method is implemented using a network of workstations. The process of reconstructing images with twin-image removal from holograms is performed in parallel with respect to different reconstruction planes of interest. This process contributes to possible faster three-dimensional object identification to be investigated in future research.

关键词： Holography Image reconstruction Holographic optical components Optical recording Convolution Optical filters Concurrent computing Parallel processing Master-slave Mathematics

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Causal spatio-temporal correlations of short scale length solar wind acceleration and heating mechanisms with a Solar Event Correlation Analyzer

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AIP Conference Proceedings 1997年第1期385卷 145-152页

作者： T. E. Evans R. A. Moyer E. Stephan R. T. Snider W. A. Coles General Atomics PO Box 85608 San Diego California 92186 Fusion Energy Research Program University of California San Diego La Jolla California 92093 Center for Astrophysics and Space Sciences University of California San Diego La Jolla California 92093 Department of Electrical and Computer Engineering University of California San Diego La Jolla California 92093

It is generally agreed that the primary scientific goal of the first near Sun fly-by mission is to identify the source of momentum responsible for driving the solar wind and to understand the physics of solar coronal heating. In this paper, we present an innovative concept for obtaining a unique set of data with which to better understand the physics of solar wind acceleration and coronal heating. The instrument, called the Solar Event Correlation Analyzer (SECA), operates on the principle that the topology of the open magnetic field lines can be used to causally correlate the evolution of small scale structures (events) in the Sun’s transition region with in situ solar probe measurements. These small-scale events are generally viewed as the mechanisms providing energy and momentum for the solar corona and wind, an assumption that will be conclusively tested with the SECA instrument. This paper describes the SECA concept and its scientific justification.

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Correction to "A Bioelectric Inverse Imaging Technique Based On Surface Laplacians"

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IEEE Transactions on Biomedical engineering 1997年第11期44卷 1163-1163页

作者： Bin He Dongsheng Wu Department of Electrical Engineering and Computer Scince and Bioengineering Program University of Illinois Chicago Chicago IL USA Bioengineering Program University of Illinois Chicago Chicago IL USA

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Operational systems, logistics engineering and technology insertion

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NAVAL ENGINEERS JOURNAL 1997年第3期109卷 205-220页

作者： Grubb, MJ Skolnick, A Michael J. Grubb:has perfomzed naval engineering at the Crane Division Naval Surface Warfare Center (NSWC) for more than twenty-five years. He currently the program manager for the Sustainable Hardware and Affordable Readiness Practice Program (SHARP). is a Navy-wide logistics research and development prgram aimed at the successful transiton of proved technologies inot the fleet. SHARP focuses on reducing acquisition performance capability reliability maintainability and readiness of these systems. Mr. Grubb has served as a department director for the past eleven years. His most recent assignment was as director of the Tactical Computer Resources and Test Equipment Department. This organization provided acquisition and in-service engineering support of the Navy's tectical embedded computers priphirals displays and mass memory storage devices. The organization also provided a complete range of product engineering and metrology engineerig services for SSP NevSeaSysCom and the Trident Program. Prior to this appointment Mr. Grubb was deptuy director psysical security programs department and site responsible for program management and system integration of ashore integrated security systems. Mr. Grubb holds a B.S. degree in industrial engineering from Iowa State Universtiy an M.S. degree in industrial engineering from Purdue University and has copleted the course work (Dec.'96 for a master's degree in public and environment affairs at Indiana University-Purdue Univeristy Indianapolis. Dr. Alfred Skolnick operates System Science Consultants (SSC) specilizing in strategic planning technical program definiton technology assessment and engineering analyses on selected matters of national interest. He has taught physics mathematics and management sciences at University of Virginia and Marymount University and is currently adjunct professor of mathematics at Northern Virginia Community College. Form 1985 to 1989 he was president of the American Society of Noval Engineers. Dr. Skolnick served at Applied Physic

In an era of fiscal austerity, downsizing and unforgiving pressure upon human and economic capital, it is an Augean task to identify resources for fresh and creative work. The realities of the day and the practical demands of more immediate fleet needs can often dictate higher priorities. Yet, the Navy must avoid eating its seed corn. Exercising both technical insight and management foresight, the fleet, the R&D community, the Office of the Chief of Naval Operations (OpNav) and the product engineering expertise of the Naval Surface Warfare Center (NSWC) are joined and underway with integrated efforts to marry new, fully demonstrated technologies and operational urgencies. Defense funding today cannot sponsor all work that can be mission-justified over the long term because budgets are insufficient to support product maturation within the classical development cycle. However, by rigorous technical filtering and astute engineering of both marketplace capabilities and currently available components, it is possible in a few select cases to compress and, in effect, integrate advanced development (6.3), engineering development (6.4), weapon procurement (WPN), ship construction (SCN), operation and maintenance (O&M,N) budgetary categories when fleet criticalities and technology opportunities can happily meet. In short, 6.3 funds can be applied directly to ''ripe gateways'' so modern technology is inserted into existing troubled or aging systems, sidestepping the lengthy, traditional development cycle and accelerating practical payoffs to recurrent fleet problems. To produce such constructive results has required a remarkable convergence of sponsor prescience and engineering workforce excellence. The paper describes, extensively, the philosophy of approach, transition strategy, polling of fleet needs, technology assessment, and management team requirements. The process for culling and selecting specific candidate tasks for SHARP sponsorship (matching operational need with t

关键词： Naval vessels

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Three-dimensional computation of light scattering from cells

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IEEE JOURNAL OF SELECTED TOPICS IN QUANTUM ELECTRONICS 1996年第4期2卷 898-905页

作者： Dunn, A RichardsKortum, R Biomedical Engineering Program Department of Electrical and Computer Engineering University of Technology Austin TX USA

Using the finite-difference time-domain method, three-dimensional scattering patterns are computed for cells containing multiple organelles. The scattering cross section and average cosine of the scattering angle are computed for cells as a function of volume fraction of melanin granules and mitochondria, Results show that small organelles play a significant role in light scattering from cells, and the volume fraction of organelles affects both the total amount of scattered light and the angular distribution of scattered light.

关键词： Light scattering Optical scattering Mie scattering Electromagnetic scattering Cells (biology) Optical refraction Finite difference methods Time domain analysis Biomedical optical imaging High-resolution imaging

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Sources of contrast in confocal reflectance imaging

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APPLIED OPTICS 1996年第19期35卷 3441-3446页

作者： Dunn, AK Smithpeter, C Welch, AJ RichardsKortum, R []The authors are with the Department of Electrical and Computer Engineering Biomedical Engineering Program University of Texas at Austin Austin Texas 78712

The relationship between optical properties and image contrast in confocal imaging is investigated. A Monte Carlo simulation has been developed to analyze the effects of changes in scattering, index of refraction, and absorption in a three-layer medium. Contrast was calculated from the computed signal-to-background ratios for changes in tissue optical properties. Results show that the largest source of contrast is changes in refractive index. (C) 1996 Optical Society of America

关键词： .Monte Carlo optical properties pinhole detector relative contributions signal-to-background source of contrast signal contrast

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On the theory of emission and absorption of electromagnetic radiation - An argument

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INTERNATIONAL JOURNAL OF electrical engineering EDUCATION 1996年第3期33卷 195-208页

作者： Gluskin, E Department of Electrical and Computer Engineering Ben-Gurion University of the Negev Beer-Sheva Israel and The Electrical Engineering Program The College of Judea and Samaria Ariel Israel

A more complete than usual use of the argument of the identity of photons is suggested for the teaching of radiation processes at the elementary level. The argument uses the concept of 'observability', known from system theory for estimating in the quantum-mechanical and statistical contexts, of the probability of occurrence of a casual process. The introductory discussion in Section 2 explains the reasonability of learning optoelectronics in the device-applicative, physical and system-theoretic aspects, with some emphasis associated with the research interests and pedagogical views of the author.

关键词： Photon Observability Disputes radiation process theories occurrence rate Systems Theory Electromagnetic Radiation personal identity

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