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IEEE Photonics Conference (IPC)

作者： S.N. Fochs G.P. Le Sage J.D. McNally F.V. Hartemann N.C. Luhmann M.D. Perry K.R. Chu J.P. Heritage Department of Applied Science University of California Davis CA USA Lawrence Livermore National Laboratories Livermore CA USA Department of Physics National Tsing Hua University Hsinchu Taiwan Electrical and computer Engineering University of California Davis CA USA

An Al mirror photocathode is used as an integral part of an optical resonator, to demonstrate the production of multiple, high charge, short duration photoelectron bunches, coherently phased at 0.250 GHz.

关键词： Cathodes Optical resonators Mirrors Radio frequency Artificial intelligence Electron beams Optical pulses Pulse measurements Pulse amplifiers Laboratories

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3-D EDGE ELEMENT ANALYSIS OF DIELECTRIC-LOADED RESONANT CAVITIES

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INTERNATIONAL JOURNAL OF NUMERICAL MODELLING-ELECTRONIC NETWORKS DEVICES AND FIELDS 1994年第1期7卷 35-41页

作者： ZHU, ZL DAVIES, JB FERNANDEZ, FA Department of Electronic and Electrical Engineering University College London WC1E 7JE U.K. On leave from the Department of Radio Electronics Peking University Beijing 100871 People's Republic of China. Le-zhu Zhou was born in Guizhou China in 1944. He received the B.S. degree in Physics and M.S. degree in Electronics from Peking University Beijing China in 1968 and 1981 respectively. Since 1981 he has been on the staff of the Department of Radio-Electronics of Peking University. In 1983 he was appointed as a Lecturer. In 1989 he became an Associate Professor. Since September 1991 he has been doing research as an Academic Visitor at the Department of Electronic and Electrical Engineering of University College London. He has been engaged in the electromagnetic field theory and its application. Recently his research interest has been in the computer modelling of optical and microwave structures by using edge element methods. J. Brian Davies was born in Liverpool England in 1932. He received the B.A. degree in mathematics in 1955 from Jesus College Cambridge England. He received the M.Sc. degree in mathematics the Ph.D. degree in mathematical physics and the D.Sc. (Eng) degree in engineering in 1957 1960 and 1980 respectively from the University of London England. From 1955 to 1963 he worked at the Mullard Research Laboratories Salford Surrey England except for two years spent at University College London. In 1963 he joined the academic staff of the Department of Electrical Engineering University of Sheffield England. Since 1967 he has been on the staff at University College London where he is now Professor of Electrical Engineering. From 1971 to 1972 he was Visiting Scientist at the National Bureau of Standards Boulder CO. In 1983 he was a Visitor at the Department of Engineering Science University of Oxford England. From 1988 to 1989 he was a Visiting Professor at the University of Colorado Boulder CO. His research interests have included microwave and optical aspects of electr

The eigenmodes in electromagnetic cavities, loaded with arbitrarily shaped dielectric materials, are computed by the edge element method. The computation shows that the well known 'spurious modes' no longer appear. Formulae are given and verified so that the number of zero eigenvalues, which come from del x H = 0, may be accurately predicted. Formulae for the order and density of the global matrices are given for a rectangular cavity regularly divided into bricks and tetrahedra, allowing an associated comparison between the contrasting edge and nodal element formulations. Comparison of the computed results with available theoretical and previously published data show the edge element approach to be a robust, accurate and effective method.

关键词： Dielectric waveguides

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Inversion of soil moisture with radar backscattering data

Inversion of soil moisture with radar backscattering data

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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： J.C. Souyris L. Wang C.C. Hsu J.A. Kong T. Le Toan N. Boudier S.H. Yueh U. Wegmuller C. Matzler Department of Electrical Engineering aud Computer Science Massachusetts Institute of Technology USA Centre dE28099Etude Spatiale des Rayonnements CNRS France Jet Propulsion Laboratory California Institute of Technology USA Institute of Applied Physics University of Bern Switzerland

The influence of surface roughness on the radar backscatter has been studied using several existing theoretical approaches. The simulation results showed a very strong sensitivity of the radar backscattering coefficients on the variations of the parameters characterizing the surface roughness. In order to assess the use of multifrequency or multipolarization data for soil moisture inversion without full knowledge of the surface roughness parameters, neural networks are applied to simulated data. The copolarised multifrequency data have been simulated using the IEM model and the multipolarized data (co and crosspolarization) have been simulated using a polarimetric model the authors developed under the small perturbation assumption.< >

关键词： Soil moisture Radar Backscatter Rough surfaces Surface roughness Scattering Neural networks Frequency Shape Perturbation methods

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BROAD-BAND ISLAND INTERCONNECTION VIA SATELLITE - PERFORMANCE ANALYSIS FOR THE RACE-II CATALYST PROJECT

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1994年第3期12卷 223-238页

作者： HADJITHEODOSIOU, MH KOMISARCZUK, P COAKLEY, F EVANS, BG SMYTHE, C Centre for Satellite Engineering Research University of Surrey Guildford GU2 5XH U.K. Obtained an M.A. in Electrical and Information Sciences from the University of Cambridge in 1989 and an M.S. in Electrical Engineering from the University of California Irvine in 1991. He is currently a Research Fellow at the Centre for Satellite Research University of Surrey U.K. His research interests include multiple access protocols for VSAT networks voice/data integration in low-bit-rate networks and the use of satellites for the provision of BISDN services. Obtained a B.Sc. in Pure and Applied Physics with Electronics in 1983 and an M.Sc. in Modern Electronics in 1984 from the University of Nottingham U.K. He was a project engineer on the Corporate Data Network for the Central Electricity Generating Board U.K. and then a senior lecturer in communication systems at the University of Greenwich UK. At present he is working on his Ph.D. at the Centre for Satellite Engineering Research (CSER) University of Surrey on the performance of communication systems. Has been Senior Lecturer in the Department of Electrical Engineering University of Surrey since 1984. She is the author (or joint author) of more than 80 research papers. Currently she teaches courses in Telecommunication Networks and Computer Architecture. Her research interests include on-board processing for satellites protocols and performance issues. Received the BSc. and Ph.D. degrees in Electrical Engineering and Microwave Systems from the University of Leeds in 1965/1968. He was British Telecom Lecturer-Reader in Telecommunications Systems at the University of Essex from 1969–1983. In 1983 he was appointed to the Alec Harley Reeves Chair of Information Systems Engineering at the University of Surrey and in 1990 became the first Director of the post-graduate centre for Satellite Engineering Research which houses some 100 researchers. In 1992 he was made a Fellow of the Royal Academy of Engineers in the U.K. and is a Fellow of IEE and a member of IEEE

The use of communication satellites as a possible way of offering broadband island interconnectivity appears to be a very attractive option, as it will enable the provision of an all-digital, transparent service to a number of ATM islands spanning a wide area, accommodating efficiently a variety of traffic demands. The CATALYST Project (RACE II/R2074) is an attempt to demonstrate the applicability and compatibility of satellite technology with the terrestrial BISDN. In this paper we present an overview of the project and focus on an initial study of the expected user performance through the CATALYST network. Our analysis is based upon mathematical and simulation models and describes the end-system to end-system transfer delay for given message lengths. The protocol profiles assume a mix of Novell NetWare and Network File System client/server architectures, which are supported by either the IEEE 802.3/Ethernet or fibre distributed data interface LANs, which are themselves linked via LAN/ATM/satellite interface units. Areas of further investigation, and the implication of our analysis on the actual network architecture, are discussed.

关键词： ASYNCHRONOUS TRANSFER MODE (ATM) BROAD-BAND ISDN SATELLITE COMMUNICATIONS

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EFFECTS OF AXIAL TENSION AND REDUCED AIR-PRESSURE ON THE RADIAL THERMAL-CONDUCTIVITY OF A STRANDED CONDUCTOR

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IEEE TRANSACTIONS ON POWER DELIVERY 1993年第2期8卷 553-558页

作者： MORGAN, VT FINDLAY, RD Department of Electrical and Computer Engineering McMaster University Hamilton ONT Canada Division of Applied Physics CSIRO Lindfield Australia

Analysis of the radial flow of heat in a multi-layer stranded conductor carrying current indicates that most of the heat is conducted through the very thin air gaps at the contacts between strands in adjacent layers and through the triangular or rectangular voids between layers. The theory predicts that, with constant current, the radial temperature difference increases as the axial tension decreases, and as the air pressure decreases. To confirm these predictions, a length of 91/4.04 mm AAC conductor was tensioned within a vacuum chamber, and the temperature of each layer of wires was measured for various total currents. It was found that the radial temperature difference increased with increasing resistive power loss per unit length, with decreasing axial tension, and with decreasing air pressure. The effective radial thermal conductivity is independent of the power loss, and increases with increasing axial tension and increasing air pressure. The calculated effective gap at the contacts is 0.5 to 0.9 mum.

关键词： Thermal conductivity Temperature Conductors Conducting materials Wires Thermal resistance Resistance heating Contact resistance physics Australia

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Micromachined 50jim x 25opm silicon torsional mirror arrays for optical signal processing

Micromachined 50jim x 25opm silicon torsional mirror arrays ...

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Integrated Optics and Microstructures 1992

作者： Hsiang, Pinju Garcia-Valenzula, Augusto Neifeld, Mark A. Tabib-Azar, M. Department of Electrical Engineering and Applied Physics Case Western Reserve University ClevelandOH44106 United States Department of Electrical and Computer Engineering University of Arizona TucsonAZ85721 United States

We propose an array of electrostatically driven torsional mirrors for optical signal processing. This 10-element device is 1-dimensional with pixels of 50im x 250im. The device is basically a hybrid integrated optical device which is fabricated in silicon and can be integrated with photodetectors and processing electronics to create elements of the so-called "smart pixel" class of spatial light modulators. This class of devices will find application in many areas of optical processing including optical interconnects, optical switching, optical image analysis and optical neural networks. We discuss the design and fabrication of mirror arrays and electrode strips that are used to actuate them. The resonant frequency and deflection angle v.5. applied voltage of the fabricated devices are measured and compared with theoretical predictions. © 1993 SPIE. All rights reserved.

关键词： Silicon

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An array based network analyzer for broadband ISDN 26

An array based network analyzer for broadband ISDN

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26th Hawaii International Conference on System Sciences, HICSS 1993

作者： Metallinos, S.N. Reisis, D.I. Stassinopoulos, G.I. Division of Computer Science Department of Electrical Engineering National Technical University of Athens Zographou Athens15773 Greece Division of Applied Physics University of Athens Greece

ISBN: (纸本)0818632305

An array based network analyzer for broadband integrated services digital networks is presented. The analyzer is a real time processing system which receives data patterns from a generator on the network to produce statistics and various measurements with respect to the network's characteristics. The design uses a linear array of processing elements for computing the required measurements. The analyzer design presented is laid out as a uniform linear array which can be implemented at low costa and can be attached to a microprocessor. It is also possible to use the analyzer array in combination with commercially available hardware to debug the network equipment in the development phase. © 1993 IEEE.

关键词： Broadband networks

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Theory of The Active Nonlinear Coupler Laser

Theory of The Active Nonlinear Coupler Laser

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Nonlinear Guided-Wave Phenomena, NLGW 1993

作者： Walton, Donnell T. Winful, Herbert G. Applied Physics Program University of Michigan 1301 Beal Ave. Rm 1214 Ann ArborMI48109 United States Department of Electrical and Computer Engineering University of Michigan 1301 Beal Ave. Ann ArborMI48109 United States

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Third-order sum-frequency generation in droplets: Model with numerical results for third-harmonic generation

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Journal of the Optical Society of America B: Optical physics 1993年第1期10卷 16-33页

作者： Hill, Steven C. Leach, David H. Chang, Richard K. Atmospheric Sciences Laboratory NM 88002 White Sands Missile Range United States Department of Electrical and Computer Engineering New Mexico State University Las Cruces NM 88003 United States Department of Applied Physics and Center for Laser Diagnostic Yale University New Haven CT 06520 United States

Steady-state model of third-order sum-frequency generation (TSFG) in liquid droplets is presented. A thirdorder polarization is generated in a droplet by stimulated Raman scattering (SRS) or by SRS in combination with fields at the incident laser frequency. This third-order polarization radiates inside the sphere as described in the general model of Chew et al. [Phys. Rev. A 19, 396 (1976)]. The frequency of the third-order polarization will only rarely be within a few linewidths of a high-Q output morphology-dependent resonance (MDR). The TSFG intensity is proportional to the spatial and frequency overlap between the generating polarization and the fields of the output modes. For a distribution of particle sizes, the probability of detecting TSFG increases with the density of output MDR's. Numerical results are presented for the specific case of the generation of the third harmonic of the first-order SRS. Although the comparison with experiment is only qualitative, the theory is consistent with experimental observations that TSFG in droplets is detectable at only a small fraction of the droplet sizes and is 4-6 orders of magnitude weaker than SRS. © 1993 Optical Society of America.

关键词： Brillouin scattering Phase matching Resonant modes Spatial frequency Stimulated scattering Sum frequency generation

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An array based network analyzer for broadband ISDN

An array based network analyzer for broadband ISDN

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Annual Hawaii International Conference on System Sciences (HICSS)

作者： S.N. Metallinos D.I. Reisis G.I. Stassinopoulos Division of Computer Science Department of Electrical Engineering National and Technical University of Athens Athens Greece Division of Applied Physics University of Athens USA

关键词： B-ISDN Asynchronous transfer mode Telecommunication traffic Intserv networks Microprocessors Phased arrays Real time systems Streaming media Semiconductor device measurement computer science

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