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IEEE Symposium (IUS) Ultrasonics

作者： C.L. Wang C.S. Tsai Department of Electrical and Computer Engineering and Institute for Surface and Interface Science University of California Irvine CA USA

Compact magnetostatic forward volume wave-based guided-wave magnetooptic (MO) Bragg cell modules have been realized by utilizing a pair of samarium-cobalt (Sm-Co) permanent magnets together with a pair of current-carrying coils. Detailed design procedures of this compact magnetic housing are presented. A tunable DC magnetic field as large as 2446 Oe corresponding to a tunable carrier frequency band of 6.85 GHz has been achieved. The resulting MO Bragg cell modules with carrier frequencies ranging from 2.0 to 12.0 GHz have provided performance characteristics comparable to those obtained by using a bulky electromagnet at the optical wavelength of 1.303 mu m. Compact MO Bragg cell modules of even higher carrier frequency, larger range of tunable carrier frequency, and smaller size can be constructed to facilitate other potential applications.< >

关键词： Magnetostatic waves Magnetic flux Frequency Permanent magnets Saturation magnetization Magnetic materials Magnetic circuits Coils Magnetic fields Electromagnets

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Analysis of current Source Induction Motor Drive Fed from Photovoltaic Energy Source

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IEEE Power engineering Review 1991年第3期11卷 39-39页

作者： Oio, Olorunfemi Department of Electrical Engineering Tennessee Technological University Cookeville TN United States

The transient and steady state analysis of an induction motor fed from a photovoltaic energy source through a currentsource inverter is presented in this paper. It is shown that the steady state and dynamic behaviors of the motor differ considerably from the case in which it is fed from a perfect current source. In particular, the steady state capability of the motor is limited by the chopping ratio of the de-de converter and the switching frequency of the current-source inverter. Analysis of the small signal perturbation equations of the system shows that the system is lightly damped for operating voltages of the array that are less than that of the array voltage corresponding to array maximum output power. For some values of array voltage, it has a non-minimum phase characteristic due to the non-linear relationship between the array voltage and current. This non-minimum phase characteristic adds an inherent difficulty to the design of a robust closed loop feedback controller for the motor drive system. © 1991 IEEE. All rights reserved.

关键词： Induction motor drives Voltage Phased arrays Steady-state optical arrays Motor drives Photovoltaic systems Solar power generation Inverters Transient analysis

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Photocathode driven linac at UCLA for FEL and plasma wakefield acceleration experiments

Photocathode driven linac at UCLA for FEL and plasma wakefie...

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IEEE Conference on Particle Accelerator

作者： S. Hartman F. Aghamir W. Barletta D. Cline J. Dodd T. Katsouleas J. Kolonko S. Park C. Pellegrini J. Rosenzweig J. Smolin J. Terrien J. Davis G. Hairapetian C. Joshi N. Luhmann D. McDermott Department of Physics University of California Los Angeles Los Angeles CA USA Department of Electrical Engineering University of California Los Angeles USA

The UCLA compact 20-MeV/c electron linear accelerators is designed to produce a single electron bunch with a peak current of 200 A, an RMS energy spread of 0.2% or less, and a short 1.2-ps RMS pulse duration. The linac is also designed to minimize emittance growth down the beamline so as to obtain emittances on the order of 8 pi mm-mrad in the experimental region. The linac will feed two beamlines, the first will run straight into the undulator for FEL experiments while the second will be used for diagnostics, longitudinal bunch compression and other electron beam experiments. A description is given of the considerations that went into the design of the accelerating structures and the transport to the experimental areas.< >

关键词： Cathodes Linear particle accelerator Plasma accelerators Acceleration Electron beams Space charge Solenoids optical pulses Laser beams Copper

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Evaluation of Electric Fields Induced in Biological Systems

Evaluation of Electric Fields Induced in Biological Systems

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9th International Zurich Symposium and Technical Exhibition on Electromagnetic Compatibility

作者： Stanislaw S. Stuchly Maria A. Stuchly Departement of Electrical Engineering University of Ottawa 770 King Edward Avenue Ottawa Ontario K1N 6N5 - Canada Burreau of Radiation and Medical Devices Room 66 HPB Ottawa Ontario K1A 0L2 - Canada

ISBN: (纸本)9781509031948

We describe several recent developments in our laboratory, that deal with external fields measurement and theoretical and experimental dosimetry evaluation of the induced electric fields, and place them in a broader picture of the current state of knowledge. Recently, we have developed antennas and sensors for transient and pulsed electric and magnetic fields. This resulted in the development of several active and electro-optical devices capable of measurements of single (transient) and multiple electric and magnetic field pulses. In the area of dosimetry, extensive measurements of induced electric fields were made in a homogeneous and heterogeneous model of man exposed in the far-field and in the nearfield of various sources ranging in frequency from 150 to 915 MHz. A numerical analysis using the finite- difference time-domain method was also performed and its results were found to be in general agreement with the experimental data.

关键词： Magnetic field measurement Numerical models Electric fields Dosimetry Electric variables measurement Biological system modeling Time-domain analysis Finite difference methods Computational modeling Biomedical measurement

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A fault tolerant reconfigurable ATM switch fabric

A fault tolerant reconfigurable ATM switch fabric

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IEEE Annual Joint Conference: INFOCOM, IEEE Computer and Communications Societies

作者： S.-C. Yang J.A. Silvester Department of Electrical Engineering-Systems University of Southern California Los Angeles CA USA

A high-bandwidth reconfigurable asynchronous transfer mode (ATM) switch fabric is proposed. The design is modular to allow for expansion to a large switch size and is feasible for implementation with current technology 2*2 buffered electronic crossbar switches. It uses wavelength division multiplexing of fiber channels in combination with nonagile tunable laser diodes. A novel approach for reconfiguration of the switch fabric is proposed. It is shown that with relatively low hardware overhead, a highly reliable switch fabric can be achieved while maintaining high bandwidth. Maximum fault tolerance is studied by mapping to the marriage problem of graph theory. The results provided by this approach significantly reduce the tuning range needed for reconfiguring the switch.< >

关键词： Switches Fault tolerance Asynchronous transfer mode Fabrics optical buffering Wavelength division multiplexing Tunable circuits and devices Diode lasers Hardware Maintenance

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ARTIFICIAL NEURAL NETWORKS AND THEIR APPLICATION TO WEAPONS

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NAVAL ENGINEERS JOURNAL 1991年第3期103卷 46-59页

作者： WEBSTER, WP The Author The Author is the technology manager for the Intercept Weapons Department at the Naval Weapons Center China Lake Calif. Dr. Webster received his B.S. M.S. and Ph.D. degrees in electrical engineering at the University of Arizona Tucson Arizona in 1964 1966 and 1971 respectively. While at the University of Arizona his studies focused on electromagnetic field propagation and scattering and laser radar system design. Since graduation he has worked at the Naval Weapons Center in a variety of technology areas including laser radar system design infrared system design proximity fuze system design hybrid and monolithic microelectronic circuit design and fabrication technology airborne fire control sensor technology and anti-air and anti-surface missile guidance and control technology. Currently he is responsible for identifying selecting and directing the development of advanced guidance sensor signal processing and aerodynamic control system technologies for application to U.S. Navy tactical electro-optical and radio frequency air intercept missiles. Dr. Webster is a member of IEEE Sigma Xi and Tau Beta Pi.

Complex processing algorithms associated with requirements for real-time target detection, acquisition and recognition have far outdistanced our ability to package the necessary processing power into real-time weapon-sized hardware. Weapon developers need new, radically different, approaches to solve these difficult weapon signal processing problems. Artificial neural networks (ANN) is one of the new, radically different, signal processing approaches that is currently receiving much attention for weapon applications. The human brain is a powerful image and pattern recognition processor whose basic processing element is the neuron. Synapses are the weighted interconnections between neurons that permit learning and communication between the neurons. Artificial neural network technology attempts to mathematically and/or electrically model neurons and synapses and then interconnect these models in architectures suitable for signal processing tasks. ANN technology is particularly applicable to pattern recognition, speech recognition, machine vision, robotics, and optimization signal processing tasks. Specific military applications include missile seekers, missile fuzing, sonar target discrimination, automatic target recognition, and autopilots. Two unique characteristics of ANN processors are that they are non-linear processors and that they are trained, not programmed, to accomplish processing tasks in a manner analogous to the way the human brain learns. Learning is achieved by modifying the synaptic weights of each artificial neuron until the final desired system processing response is achieved. Several years ago the Naval Weapons Center (NavWpnCen) identified ANN technology as a high risk-high payoff approach to missile signal processing requirements and initiated several research and development efforts in this area. One result of this work is the new 80170NW ANN analog VLSI chip produced by Intel Inc. Another is the current Missileborne Integrated Neural Network De

关键词： Neural Networks

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Microbending optoelectronic sensor for on‐line temperature measurements in high‐power electrical systems

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European Transactions on Electrical Power 1991年第5期1卷 281-287页

作者： Cutolo, A. Gallo, M. Prof. Dr.-Ing. Antonello Cutolo (1955) took his doctor degree in electronic engineering in 1978. After spending one year in the Italian Air Force he worked for one year at the Applied Mathematical Physics Dep. of the Technical University of Denmark (working on Josephson junctions) for about two years at the High Energy Physics Laboratory of Stanford University in CaliforniaIUSA (working on free electron lasers) and for about two years at the Adone Storage Rings in FrascatiAtaly (working on free electron lasers). Since 1988 he was appointed associated professor of quantum electronics at the University of Napolintaly where he is now the head of a laser laboratory. His current interests involve diagnostics of ultra-short laser pulses optoelectronic diagnostics of electronic devices and circuits and optical fiber sensors. (Department of Electronic Engineering University of Napoli Via Claudio 21 1-80125 Napoli T +3981/76811 11) Dr.-Ing. Mario Gallo (1965) took his doctor degree in electronic engineering in 1990. His thesis deals with the design and test of an optoelectronic sensor for temperature measurements in electric systems. At the present time he is ernployed in the TIRMAS company at Napolifltaly working on the diagnostics of telephone apparatus. (Department of Electronic Engineering University of Napoli Via Claudio 2 I I-80125NapoliT+3981/76811 11)

Relying on well known technology for microbending sensors largely used in high sensitivity pressure measurements, an optoelectronic sensor for temperature measurements was devised and successfully tested. It can prove extremely useful for on‐line and real‐time diagnostics of high‐power electrical systems. The major advantages of this sensor are low cost, easy handling, high electromagnetic compatibility and good precision: Some preliminary experimental results confirm the feasibility of the device. Although the results have been finalized to the real‐time diagnostics of temperature profiles in high‐power electrical systems, their extension to other fields is straightforward. Copyright © 1991 John Wiley & Sons, Ltd.

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design OF PHOTOLITHOGRAPHIC LENSES WITH LARGE FIELD AND APPROXIMATE BITELECENTRICITY

DESIGN OF PHOTOLITHOGRAPHIC LENSES WITH LARGE FIELD AND APPR...

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CONF ON current developments IN optical engineering 4

作者： WANG, XC LIN, DJ Institute of Optics and Electronics (China) Institute of Optics and Electr (China)

ISBN: (纸本)0819403954

This paper introduced a new type of tenses with approximate bite lecentricity for *** has the quasi-diffraction Limited image quality in the range of large field size and keeps fine overlay accuracy as *** corrections of sagittal aberrations and higher order aberrations are considered in the optical design. Finaty, the MTF of two results, with NAO•2, magnification x, field diameter 140mm, and NAO•28, magnification lOX, field diameter 140mm, were given.

关键词： Monochromatic aberrations optical design Lenses optical engineering Distortion Diffraction Lens design Modulation transfer functions Semiconducting wafers Optics manufacturing

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EVALUATION OF optical-SYSTEMS designED USING THE CONCENTRIC-APLANATIC METHOD

EVALUATION OF OPTICAL-SYSTEMS DESIGNED USING THE CONCENTRIC-...

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CONF ON current developments IN optical engineering 4

作者： DESLIS, A Jet Propulsion Lab Pasadena United States

ISBN: (纸本)0819403954

The 'concentric-aplanatic' method used for lens design is described in many papers. While many shapes and forms of these lenses have been shown, performance evaluation of these lenses has never been published. How good is the method? Can one design optical systems using this technique that have acceptable image quality? This paper will deal step by step with these questions, both from first principles and by the basis of third order theory. Performance evaluations will be given for the lenses designed.

关键词： optical Systems

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DISCUSSION OF REFLECTION MICROCIRCULATION MICROSCOPE design

DISCUSSION OF REFLECTION MICROCIRCULATION MICROSCOPE DESIGN

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CONF ON current developments IN optical engineering 4

作者： ZHENG, DY CHEN, RY GE, ZF JING, FQ HU, WF WANG, BM Zhejiang Univ. (China) Hangzhou Traditional Chinese Medicine Hospital (China)

ISBN: (纸本)0819403954

Reflection microcirculation microscope has wide application value in studyiny microcirculation and microrheology , and joining with different equipment can do many ways of the studies , So research and improvement the instrument and development advanced appendant technology will produce a active sence to the study of biomedicine. In this paper , We introduce mainly the design idea of reflection microcirculation microscope which was studied by us ,and discuss some prombles.

关键词： Microscopes Objectives Blood Capillaries optical engineering Organisms Photography Illumination engineering Image analysis Image transmission

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