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Aspects of the structure and reactivity of Femoco using synchrotron-based x-ray absorption and scattering methods

Journal of Inorganic Biochem.s.ry 1993年第1期51卷 375-375页

作者： Britt Hedman Lingling Chen David Eliezer Isaac Liu Hirotsugu Tsuruta Narasaiah Gavini William E. Newton Barbara K. Burgess Patrick Frank Keith O. Hodgson Stanford Synchrotron Radiation Laboratory Stanford University SLAC M.S. 69 P.O. Box 4349 Stanford CA 94309 USA Department of Chemistry Stanford University Stanford CA 94305 USA Department of Applied Physics Stanford University Stanford CA 94305 USA Department of Molecular Biology and Biochemistry University of California at Irvine Irvine CA 92717 USA Department of Biochemistry and Nutrition Virginia Polytechnical Institute Blacksburg VA 24061 USA

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New insights into the structure and reactivity of Femoco and nitrogenase using x-ray absorption and scattering techniques

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Journal of Inorganic Biochem.s.ry 1993年第1期51卷 358-358页

作者： Lingling Chen David Eliezer Isaac Liu Hirotsugu Tsuruta Narasaiah Gavini William E. Newton Barbara K. Burgess Patrick Frank Britt Hedman Keith O. Hodgson Department of Chemistry Stanford University Stanford CA 94305 USA Department of Applied Physics Stanford University Stanford CA 94305 USA Stanford Synchrotron Radiation Laboratory Stanford University SLAC M.S. 69 P.O. Box 4349 Stanford CA 94309 USA Department of Molecular Biology and Biochemistry University of California at Irvine Irvine CA 92717 USA Department of Biochemistry and Nutrition Virginia Polytechnical Institute Blacksburg VA 24061 USA

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Electric field calculation combined with a CAD system for the personal computer

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European Transactions on Electrical Power 1993年第3期3卷 227-233页

作者： Okubo, H. maehara, H. Kato, K. Hikita, m. Kito, Y. Hitoshi Okubo (1948) received the B.S. degree in 1971 the M.S. degree in 1973 and the Ph.D. in 1984 all in Electrical Engineering from Nagoya University Nagoya/Japan. He joined Toshiba Corporation/Japan in 1973 and was a manager of high-voltage laboratory of Toshiba. From 1976 to 1978 he was at the RWTH Aachen/Germany and the TU Munich/Germany where he studied high-voltage engineering. Since 1989 he was an Associate Professor and presently he is a Professor of Nagoya University at the Department of Electrical Engineering. He is a member of IEE of Japan and IEEE. (Nagoya University Department of Electrical Engineering Chikusa-ku Furo-cho Nagoya 464 Japan T +8152/ 781-5111 Fax +8152/783-4168) Hiroyuki Maehara (1966) received the B.S. degree in 1990 and the M.S. degree in 1992 all in Electrical Engineering from Nagoya University Nagoya/Japan. He joined Toshiba Corporation Kawasaki/Japan in 1992 and presently he is at the Department of high-voltage switchgear of Hamakawasaki Works. He is a member of IEE of Japan. (Toshiba Corporation High Voltage Switchgear Department Kawasaki-ku Ukishima-cho 2-1 Kawasaki 210 Japan T+8144/288-6508 Fax+8144/288-6509) Katsumi Kato (1969) received the B.S. degree in 1992 in Electrical Engineering from Nagoya University Nagoya/Japan. Presently he is a master course student of Nagoya University at the Department of Electrical Engineering. He is a member of IEE of Japan. (Nagoya University Department of Electrical Engineering. Chikusa-ku Furo- cho Nagoya 464 Japan T + 8152/781-5111 Fax +8152/783-4168) Masayuki Hikita (1953) received the B.S. degree in 1977 the M.S. degree in 1979 and the Ph.D. degree in 1982 all in Electrical Engineering from Nagoya University Nagoya/Japan and he became a research fellow there. In 1989 and 1992 he was made Lecturer and Associate Professor at Nagoya University respectively. He was Visiting Fellow at the MIT high voltage laboratory in 1985 to 1987 where his research was on the use of Kerr effect to determine charge distribu

A Personal‐Computer‐based CAD (PC‐CAD) system combined with the electric field analysis was developed and is referred to as “CADEF” (CAD system with Electric Field analysis). To construct such a system, both software and hardware need to be upgraded and the related conversion programs have to be developed. In the CADEF, the CAD drawings are fully utilized for the input data processing and the output expression of the electric field analysis. A Charge simulation method (Csm) is adopted as an analysis software. In the calculation process, singular points on the Csm.s.ch as the triple junctions are automatically recognized and processed. By introducing the expert knowledge and the experiential factors on the charge arrangements as the rules, the automatic calculation system is accomplished. Copyright © 1993 John Wiley & sons, Ltd.

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sELF-QUENCHING OF THE sEmICONDUCTOR-LAsER LINEWIDTH BELOW THE sCHAWLOW-TOWNEs LImIT BY UsING OPTICAL FEEDBACK

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OPTICs LETTERs 1992年第9期17卷 661-663页

作者： sHEVY, Y IANNELLI, J KITCHING, J YARIV, A Department of Applied Physics M.S. 128-95 California Institute of Technology Pasadena California 91125

We demonstrate theoretically and experimentally self-quenching of the fundamental semiconductor laser frequency fluctuations to a level that is orders of magnitude below the schawlow-Townes limit for a solitary laser. It is shown that the main operative mechanism is the combined action of a frequency-dependent internal loss and amplitude-to-phase coupling. The internal frequency-dependent loss is introduced by means of spectrally narrow external optical feedback, which provides a strong frequency-dependent dispersion. Linewidth reduction by a factor of 2 x 10(3) is demonstrated by using a narrow Doppler-free Faraday resonance in Cs vapor.

关键词： Extinction ratios Optical feedback Phase modulation Refractive index semiconductor lasers spontaneous em.s.ion

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EmERGENCE OF mIXED NEmATIC m.s.PHAsE IN BINARY-sYsTEm OF A NON-m.s.GEN AND A smECTOGEN

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mOLECULAR CRYsTALs AND LIQUID CRYsTALs 1992年第1期213卷 51-56页

作者： PARmAR, Cm DAVE, Js DHAKE, KP Applied Chemistry Department Faculty of Technology & Engineering M. S. University of Baroda Baroda 39001 India Applied Chemistry Department Faculty of Technology & Engineering M. S. University of Baroda Baroda 39001 IndiaApplied Physics Department Faculty of Technology and Engineering M.S. University of Baroda Baroda 390 001 India

An interesting binary system consisting of a non-m.s.gen and a smectogen viz.p-chlorophenyl-p′-methoxycinnamate (A) andp-chlorophenyl-p′-n-octyloxycinnamate (B), respectively, which belong to the same homologous series1viz.p-chlorophenyl-p′-n-alkoxycinnamates is now reported in which mixed monotropic nematic and mixed enantiotropic nematic m.s.phases emerge over a wide range of temperature and concentration. It is observed that the mixed smectic m.s.phase gets depressed as the concentration of the non-m.s.gen increases, yielding simultaneously enantiotropic mixed nematic phase; the mixed phase diagram exhibits nematic as well as smectic phases. As the concentration of the non-m.s.gen increases further, the mixed smectic phase enters into monotropic state while the mixed nematic phase continues to be enantiotropic. However, with more than about 60 mole% (A), the mixed nematic enantiotropic m.s.phase becom.s.monotropic nematic which ends by about 92 mole% of the non-m.s.gen (A). The characteristic modifications in the mixed m.s.morphism are correlated with the structural characteristics of the components of the molecular forces displayed by them.

关键词： NON-m.s.GEN smECTOGEN m.s.PHAsE TEXTURE ENANTIOTROPIC NEmATIC POLYm.s.mORPHIsm NEmATIC m.s.PHAsE

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DETERmINATION OF CRIsIs PARAmETER VALUEs BY DIRECT OBsERVATION OF mANIFOLD TANGENCIEs

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International Journal of Bifurcation and Chaos 1992年第2期2卷 383-396页

作者： JOHN C. sOmmERER CELsO GREBOGI M.S. Eisenhower Research Center The Johns Hopkins University Applied Physics Laboratory Laurel Maryland 20723–6099 USA Department of Mathematics University of Maryland College Park Maryland 20742 USA

We discuss an algorithm to find the parameter value at which a nonlinear, dissipative, chaotic system undergoes crisis. The algorithm is based on the observation that, at crisis, the unstable manifold of an unstable periodic point becom.s.tangent to the stable manifold of the same or another, related unstable periodic point. This geometric algorithm uses much less computation (or data) than estimating the critical parameter value by using the scaling relation for chaotic transients, τ~(p−p c )−γ. We demonstrate the algorithm in both numerical and experimental contexts.

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APPLICATIONs OF sUPERCONDUCTIVITY TO VERY sHALLOW-WATER mINE sWEEPING

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NAVAL ENGINEERs JOURNAL 1992年第3期104卷 53-64页

作者： GOLDA, Em WALTERs, JD GREEN, GF LCdr. E. Michael Golda:is a Naval Reserve engineering duty officer. He has provided direct support to code 2712 at the David Taylor Research Center during the last eighteen months as a member of the group studying applications of superconductivity to mine countermeasures. LCdr. Golda received his Ph.D. and M.S. in materials science and engineering from Stevens Institute of Technology Hoboken N.J. A 1977 graduate of the United States Naval Academy LCdr. Golda has been a member of ASNE since 1974. Dr. Joseph D. Walters:received his Ph.D. in physics in 1990 from Portland State University in Portland Oregon. At the University Dr. Walters work included experimental and theoretical investigations of critical heat transfer phenomena in liquid helium and theoretical research into the finite time thermodynamics of refrigeration cycles. Currently Dr. Walters is a project engineer in the cryogenic engineering group at the David Taylor Research Cen-ter(DTRC) in Annapolis Maryland. Since joining DTRC in 1990 Dr. Walters has been assessing cryogenic related issues impacting superconductivity applied to mine countermeasures including choice of superconductor refrigerator system mass and logistical arrangements. Additionally Dr. Walters is developing theoretical models designs and testing a set of high critical temperature superconducting current leads for SMES. Geoffrey F. Green:is the cryogenic engineering group leader at the David Taylor Research Center(DTRC) in Annapolis Maryland. He received his B.S. and M.S. in mechanical engineering from Pennsylvania State University in 1970 and 1972 respectively. Since then Mr. Green has worked at DTRC on the development of a superconducting electric drive system for Navy Ships. In 1980 he assumed responsibility for development of the cryogenic and machinery cooling technologies. Mr. Green has co-authored more than 25 papers/reports in cryogenic refrigeration and superconducting machinery and has several patents in cryogenics. He is on the executive committee of the P

Recent experiences in the Persian Gulf have clearly demonstrated the need for improved mine sweeping, or mine counter-measures (mCm), to support amphibious operations. Characteristics of mCm.s.stems currently used to counter magnetic influence mines restrict sweep rates, limit the ability to accurately simulate a ship's magnetic signature, and require a minimum water depth. Advances in superconducting technology over the last twenty years have significantly increased the feasibility of superconducting mine countermeasures (sCmCm) for magnetic influence mines. An sCmCm.s.stem would be small, light, and simple compared to currently deployed mCm.s.stems. superconducting magnets could be fabricated in steady state configurations or configurations that would significantly improve the ability to simulate non-symmetric, time-varying magnetic signatures of ships. sCmCm.s.stems could be deployed from either surface or airborne platforms. An airborne system would protect the magnet from blast damage, permit the highest sweep rates, and allow unrestricted sweeping over entire amphibious objective areas, including the surf. A light weight sCmCm.s.stem would permit use of additional airborne platforms which may include remotely piloted airborne vehicles. Remotely piloted surface or airborne vehicles would totally eliminate risks to personnel. An sCmCm.s.stem could be demonstrated immediately utilizing existing technology and may offer significant advantages over existing mCm.s.stems used to counter magnetic influence mines in very shallow water.

关键词： military Engineering

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NEW TECHNIQUEs IN WEAPON FIRING CUTOUT ZONE DEsIGN

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NAVAL ENGINEERs JOURNAL 1991年第3期103卷 278-290页

作者： GEORGE, E The Author received his B.S. degree in mechanical engineering from the Georgia Institute of Technology in 1982 and a M.S. degree in physics from the Virginia Polytechnic Institute and State University in 1988. Since 1984 he has worked in the Pointing and Firing Cutout Zone Program at the Naval Surface Warfare Center concentrating on computer applications in weapon safety analyses.

Weapon pointing and firing zones are critical operational parameters which directly affect the safety and capability of weapon performance and ship m.s.ion. These zones are normally implemented in the weapon system and restrict areas of weapon movement and function allowing clearance for ship structure during weapon performance. The primary purpose of the zones is to ensure topside safety by preventing the weapon from firing into surrounding ship structure. Weapon pointing and firing zones are also used to integrate weapon and other shipboard equipment functions to avoid interference conflicts. The Naval surface Warfare Center (NAVsWC) is the technical direction agent which designs weapon pointing and firing zones for every large caliber gun mount and rotating m.s.ile launcher on U.s. Navy ships. Because of the increasing complexity of topside operations and applications in computer technology, new methods are being developed to support NAVsWC weapon zone design efforts. This paper first summarizes present techniques in NAVsWC weapon zone analysis and design. The second part of the paper describes methods under development using graphic computer systems to conduct safety analyses for weapon zone design. The paper concludes with a review of future weapon cutout system improvements.

关键词： Naval Warfare

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EVALUATING THE EFFECTIVENEss OF GROUND-WATER EXTRACTION sYsTEms

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GROUND WATER mONITORING AND REmEDIATION 1991年第1期11卷 119-124页

作者： HALEY, JL HANsON, B ENFIELD, C GLAss, J Jennifer Haley is a chemical engineer working in the Remedial Operations and Guidance Branch of the Hazardous Site Control Division/Office of Emergency and Remedial Response (U.S. EPA OS-220 401 M St. SW Washington D.C. 20460). One of her responsibilities during her three years at EPA has been completion of the EPA Guidance on Remedial Actions for Contaminated Ground Water at Superfund Sites. Prior to taking her current position at the EPA in May 1987 she worked for two years for the California Regional Water Quality Control Board overseeing ground water contamination investigations and cleanups in the South San Francisco Bay. She received a B.S. in chemical engineering from the University of California in Berkeley and an M.S. in environmental management from the University of San Francisco. Bill Hanson is an engineer with the U.S. Environmental Protection Agency (OS-220 401 M St. SW Washington D.C. 20460). He received both his B.S. in engineering and M.A. in environmental engineering from Duke University. Before joining the Environmental Protection Agency Hanson worked for several consulting engineering firms including CH2M Hill in Res ton Virginia. At EPA he first worked in the Effluent Guidelines Program where he was responsible for developing pretreatment and direct discharge regulations for the electroplating industry. Hanson has been with the Superfund program since its start. He is currently chief of the Remedial Operations and Guidance Branch. His branch is responsible for developing guidance for consistency of approach with respect to selection of remedy land ban treatment requirements and treatability protocols. Carl G. Enfield is a soil scientist at the Robert S. Ken Environmental Research Laboratory (U.S. EPA Office of Research and Development P.O. Box 1198 Ada OK 74820). He earned his B.S.C.E. in civil engineering and M.S. in agronomy at Purdue University and his Ph.D. in agricultural chemistry and soils at the University of Arizona. He currently serves as research director at EP

The m.s. common process for remediating contaminated ground water is extraction and treatment. Data from 19 on-going and completed ground water extraction systems were collected and analyzed (U.s. EPA 1989b) to evaluate the effectiveness of this process in achieving cleanup concentration goals for ground water. This analysis indicated several trends including (1) containment of ground water plum.s.was usually achieved;(2) contaminant concentrations dropped significantly initially followed by a leveling out;(3) after the period of initial rapid decline, the continued decreases in concentration were usually slower than anticipated;and (4) certain data important to optimizing system design and operation had often not been collected during the site characterization phase. Factors limiting the achievement of cleanup concentration goals fell into four basic categories: (1) hydrogeological factors, such as subsurface heterogeneity, low-permeability units, and presence of fractures;(2) contaminant-related factors, such as high sorption to soil and presence of non-aqueous phases (dissolution from a separate non-aqueous phases (dissolution from a separate non-aqueous phase or partitioning of contaminants from the residual non-aqueous phase);(3) continued migration from.s.urce areas and the size of the plume itself;and (4) system design factors, such as pumping rates, screened intervals, and extraction well locations. The findings of this study indicate that ground water extraction is an effective method for preventing additional migration of contaminant plum.s.and achieving risk reduction. However, the findings indicate that in many situations, it may not be practicable to rely solely on ground water extraction and treatment to achieve health-based cleanup concentrations throughout the contaminated zone and fulfill the primary goal of returning ground water to beneficial use. This study suggests several recommendations (U.s. EPA 1989a) for improving ground water response acti

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smALL sHIPs, ADVANCED TECHNOLOGY AND WARFIGHTING PERFORmANCE

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NAVAL ENGINEERs JOURNAL 1991年第3期103卷 30-45页

作者： sKOLNICK, DH sKOLNICK, A David H. Skolnickhas practiced naval engineering in both government and industry. He has supported the Military Sealift Command and the Naval Sea Systems Command Ship Design Group and Amphibious Ship Acquisition Program Office participating in the design and assessment of ship structure evaluation of intact and damaged stability and arrangements during design and construction phases of acquisition conversion and overhaul. He is currently involved in systems engineering and integration. Recent responsibilities have included requirements analyses and feasibility studies interface analyses and computer aided analyses. He received his B.S. in naval architecture and marine engineering from Webb Institute of Naval Architecture in 1982 (as an ASNE scholar) and is currently an M.S. candidate in systems engineering at the University of Virginia. Alfred Skolnickserved over 30 years as an engineering duty officer and retired from the Navy with the rank of captain in 1983. His early assignments included tactical missile engineering shipboard duty and Polaris submarine inertial navigation. He later served in the Deep Submergence Systems Project was project director surface effect ships (SES) David Taylor Model Basin director of technology Joint Navy-Commerce SES Program director combat systems Naval Sea Systems Command and project manager directed energy weapons. His awards include the Navy League's Parsons Award in 1979 for scientific and technical progress ASNE's Gold Medal in 1981 for high energy laser development the Navy Legion of Merit in 1983 National Capital Engineer of the Year in 1986 and the American Defense Preparedness Association Gold Medal in 1988 for contributions to strategic defense. He was president of ASNE from 1985–1989. He received his B.S. in mathematics from Queens College his M.A. in mathematics from Columbia University his M.S. in electrical engineering from U.S. Naval Postgraduate School and his Ph.D. in electrical engineering/applied mathematics from Polytechnic University. He w

Changing threat requirements and radical budget shifts imply that Navy operational needs will broaden and engineering solutions will face tougher constraints. Existing and emerging technology prom.s. increased combat capability in smaller packages;space-based assets will allow operator orchestration of widely dispersed naval units via connectivity attributes previously unavailable. Tactical data relay by downlink may permit reallocation of responsibilities among several platforms, space, air, or seaborne, so ships can be outfitted for custom-use (sensing, unique data processing, high-firepower) and optimized to meet specific m.s.ion needs. These evolving capabilities demand a fresh look at ship concepts and prospective force structures consistent with global and fiscal realities. Warfighting performance formerly unknown in small ship design may offer a very effective solution to the intricate, interacting issues of falling defense budgets, diverse operational requirements and complex national priorities. multim.s.ion ships which take advantage of new or current technology to reduce ship size, manning and cost could be affordable in sufficient numbers to meet our continuing worldwide obligations, complement our larger ships' force structure, and produce a balanced fleet. These same ships could satisfy U.s. maritime needs beyond the Navy and improve export trade through foreign military sales (Fms).

关键词： Naval Warfare

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