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Asymmetric profiles observed in the recombination of Bi79+: A benchmark for relativistic theories involving interference

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Physical Review A 2009年第1期80卷 014503-014503页

作者： Nobuyuki Nakamura Anthony P. Kavanagh Hirofumi Watanabe Hiroyuki A. Sakaue Yueming Li Daiji Kato Fred J. Currell Xiao-Min Tong Tsutomu Watanabe Shunsuke Ohtani Institute for Laser Science The University of Electro-Communications Chofu Tokyo 182-8585 Japan Queen’s University Belfast Belfast BT7 1NN United Kingdom Chubu University Kasugai-shi Aichi 487-8501 Japan National Institute for Fusion Science Toki Gifu 509-5292 Japan Institute of Applied Physics and Computational Mathematics P.O. Box 8009 Beijing 100088 China Doctoral Program in Materials Science Graduate School of Pure and Applied Sciences University of Tsukuba Tsukuba Ibaraki 305-8573 Japan Center for Computational Sciences University of Tsukuba Tsukuba Ibaraki 305-8577 Japan

Asymmetric profiles have been observed in the recombination cross section of Be-like Bi obtained by measuring the electron energy dependence of the ion abundance ratio in an electron-beam ion trap. In contrast to the previous x-ray measurements, the present measurement gives the integrated recombination cross section with higher statistical quality, which provides a benchmark to test the relativistic theory involving the interference between the resonant and continuum states. The comparison with our theoretical study shows that the Breit interaction plays an important role in this case.

关键词： Benchmarking

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Search for SM Higgs in the W H → lνbb channel using ∼2fb -1

Search for SM Higgs in the W H → lνbb channel using ∼2fb ...

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43rd Rencontres de Moriond on Electroweak Interactions and Unified Theories, EW 2008

作者： Masubuchi, Tatsuya Doctoral Program in Physics Graduate School of Pure and Applied Sciences University of Tsukuba Ten'noudai 1-1-1 Tsukuba Ibaraki 305-8571 Japan

We report a search for Standard Model (SM) Higgs boson production in association with a W ± boson. This search uses data corresponding to an integrated luminosity of 1.9 fb-1 collected with the CDF detector at Tevatron. We select events matching the W + jets signature and require at least one jets to be identified as b-quark jets. To further increase discrimination between signal and background, we use kinematic information in an artificial neural network. The number of tagged events and the resulting neural network output distributions are consistent with the Standard Model expectations, and we set an upper limit on the W H production cross section times branching ratio σ(pp → W±H) × BR(H → bb) 2 to 150 GeV/c2 at 95% confidence level.

关键词： Germanium alloys

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Time-domain modeling of atmospheric turbulence effects on sonic boom propagation

Time-domain modeling of atmospheric turbulence effects on so...

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作者： Piacsek, Andrew A. Locey, Lance L. Sparrow, Victor W. Central Washington University Ellensburg WA 98926 United States Pennsylvania State University University Park PA 16802 United States Department of Physics 400 E. University Way Ellensburg WA 98926 United States Graduate Program in Acoustics 201 Applied Science Bldg. University Park PA 16802 United States

ISBN: (纸本)9781563479397

A 2-D nonlinear time domain computational model of sonic boom propagation has been modified to incorporate the effects of atmospheric turbulence. This model, based on the Nonlinear Progressive wave Equation (NPE) of McDonald and Kuperman, is used to propagate N-waves from the upper turbulent boundary layer (TBL) to the ground through different turbulence realizations. The output of the model provides detailed images of the full wave field at arbitrary heights above the ground, as well as shock profiles at specified locations along the wavefront. Preliminary results show multiple scales of spiking and rounding of shock profiles that are clearly correlated with wavefront focusing and defocusing, respectively. These waveform distortions, as well as their spatial variation along the wavefront, qualitatively match those seen in sonic booms recorded at the ground. These results are also consistent with earlier studies that applied the NPE to weak shocks with rippled wavefronts propagating through a homogeneous medium;these studies demonstrated that the combination of nonlinear and geometric effects arising from focusing wavefronts can produce the variety of distorted sonic boom waveforms observed in test flights. This paper describes the details of the sonic boom propagation code, including the implementation of turbulence effects, and discusses its performance on benchmark problems. Copyright © 2008 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.

关键词： Wavefronts

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Sonic boom post processing to include atmospheric turbulence effects

Sonic boom post processing to include atmospheric turbulence...

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作者： Locey, Lance L. Sparrow, Victor W. Piacsek, Andrew A. Pennsylvania State University University Park PA 16802 United States Central Washington University Ellensburg WA 98926 United States Graduate Program in Acoustics 201 Applied Science Bldg. University Park PA 16802 United States Department of Physics 400 E. University Way Ellensburg WA 98926 United States

ISBN: (纸本)9781563479397

The Nonlinear Progressive wave Equation (NPE) is modified to include a turbulence representation based upon temperature fluctuations. The turbulence is composed of the sum of 600 Fourier modes based on a modified von Kármán spectrum with an outer length scale of 100 m and an inner length scale of .001 m. Variations in temperature induce variations in the local speed of sound. The NPE propagates for several seconds with a propagation time step of 1e-5 s. The resultant 2D waveform is then used to generate filter functions which approximate the effects of propagation through the turbulence. The filter functions can then be used to represent turbulent propagation by convolving the filter with any waveform, assuming it has sufficient high frequency content. Copyright © 2008 by Lance L. Locey, Victor W. Sparrow, and Andrew A. Piacsek.

关键词： Nonlinear equations

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An inverted-pendulum thrust stand for high-power electric thrusters

An inverted-pendulum thrust stand for high-power electric th...

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AIAA/ASME/SAE/ASEE 42nd Joint Propulsion Conference

作者： Kodys, A.D. Murray, R. Cassady, L. Choueiri, E.Y. Electric Propulsion and Plasma Dynamics Laboratory Mechanical and Aerospace Engineering Department Princeton University Princeton NJ 08511 United States NASA Graduate Student Research Program Princeton Plasma Science and Technology Program United States EPPDyL United States Applied Physics Group United States AIAA United States

ISBN: (纸本)1563478188

The inverted-pendulum method of thrust measurement for high-power electric thrusters is described analytically and experimentally. Two sources of uncertainty in the thrust measurements are investigated: those due to changes in the sensitivity of the inverted pendulum and those due to tare forces resulting from thermal stresses and electromagnetic forces acting on the flexural elements. An idealized analytical model shows that changes in sensitivity occur due to changes in the mass loading of the inverted pendulum and the temperature of the flexure elements. The sensitivity can be increased only at the expense of more stringent requirements on mass loading and thermal control. The results of the model are validated with measurements made using a carefully calibrated inverted pendulum thrust stand having several advantageous design features including gallium pots for current conduction, an optical two-axis displacement sensor, and careful consideration of flexure shape and cooling requirements. The sensitivity is shown to be constant over a wide range of operating conditions. Measurements show that thermal drifts of the stand are linear on the time scale of the thrust measurements and are less than 0.6% of the expected thrust. The thrust stand operation was demonstrated during experiments with a 30-kW lithium-fed applied-field magnetoplasmadynamic thruster. Under nominal conditions (400 A, 0.1 T, 17.5 mg/s) the thermal and electromagnetic tare forces were measured at less than 9% of the thrust and the total thrust uncertainty at ≤ 10% of the thrust.

关键词： Electric propulsion

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Lumen loaded of kenaf pulp with magnetic pigment

Lumen loaded of kenaf pulp with magnetic pigment

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59th Appita Annual Conference and Exhibition, incorporating the 13th ISWFPC: International Symposium on Wood, Fibre and Pulping Chemistry

作者： Zakaria, Sarani Hoong, Ong Boon Ahmad, Sahrim Hj. Abdullah, Mustaffc Hj. Van De Ven, T.G.M. Yamauchi, Tatsuo Materilsl Science Program School of Applied Physics Universiti Kebangsaan Malaysia 43600 Bangi Malaysia Pulp and Paper Research Center McGill University Montreal Canada Graduate School Faculty of Agricultre Kyoto University Kyoto

Lumen-loading technology allows filler particles to be introduced exclusively into the lumens of the fibres while leaving the external surfaces free of filler. This study focuses on the development of lumen-loading process for the preparation of magnetic pulp. Magnetic pulp was prepared from unbleached kraft pulp lumen-loaded with magnetite (Fe3O4). Cationic polyethylenimine (PEI) or alum as retention aids in the lumen-loading process produced a better retention of the pigments in the preparation of this magnetic pulp. The physical properties of loading pup showed a decreased value as the filler content increased. The SEM picture showed the deposition of filler in the lumen.

关键词： Kenaf fibers

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Short-Range Spectroscopic Ruler Based on a Single-Molecule Optical Switch

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Physical Review Letters 2005年第10期94卷 108101-108101页

作者： Mark Bates Timothy R. Blosser Xiaowei Zhuang Division of Engineering and Applied Sciences Harvard University Cambridge Massachusetts 02138 USA Graduate Program in Biophysics Harvard University Cambridge Massachusetts 02138 USA Department of Chemistry Harvard University Cambridge Massachusetts 02138 USA Department of Physics Harvard University Cambridge Massachusetts 02138 USA

We demonstrate a novel all-optical switch consisting of two molecules: a primary fluorophore (Cy5) that can be switched between a fluorescent and a dark state by light of different wavelengths, and a secondary chromophore (Cy3) that facilitates switching. The interaction between the two molecules exhibits a distance dependence much steeper than that of conventional Förster resonance energy transfer. This enables the switch to act as a ruler with the capability to probe distances difficult to access by other spectroscopic methods, thus presenting a new tool for the study of biomolecules at the single-molecule level.

关键词： .switching distance PRL ending Probe dependence Demonstrate Spectroscopic uorescent short-range Single-molecule switched optical switch Ruler dark state

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Behavior of Charge Density Waves in a One-Dimensional Organic Conductor Visualized by Scanning Tunneling Microscopy

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Physical Review Letters 1998年第15期81卷 3187-3187页

作者： Tetsuya Nishiguchi Masami Kageshima Norihiko Ara-Kato Akira Kawazu Department of Applied Physics Graduate School of Engineering The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo 113-8656 Japan Frontier Research Program The Institute of Physical and Chemical Research (RIKEN) 2-1 Hirosawa Wako Saitama 351-0198 Japan

Charge density waves (CDW) in a tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) single crystal have been studied with molecular resolution using a low temperature scanning tunneling microscope (STM). For the first time the periodicities of the CDW along both the a and b axes have been observed and were found to be coincident with those of the 2kF CDW. The influence of crystal singularities on the ordering of the CDW along the a axis was also revealed.

关键词： Organic conductors

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Applying fuzzy functions and sequential coordination to optimization of machinery arrangement and pipe routing

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NAVAL ENGINEERS JOURNAL 1998年第6期110卷 43-54页

作者： Wu, BC Young, GS Schmidt, W Choppella, K Dr. Bi-Chu Wu:received a PhD in Mechanical Engineering from the University of Maryland College Park in 1991. She has worked on projects involving naval architecture design optimization solid mechanics and database development. Presently a senwr engineer with Angle Incorporated Dr Wu's research interests are in design optimization and fuzzy logic applications. Dr. Gin-Shu Young: a senior engineer with Angle Incorporated holds a PhD in Mechanical Engineering from the University of Maryland College Park. As a guest researcher with National Institute of Standards and Technologies from 1990 to 1993 he worked on vision-based navigation for autonomous vehicles. His experience also includes applications of optimization fuzzy logic neural network and genetic algorithm methods to engineering system design Mr. William Schmidt:co-founded Angle Incorporated in 1990 and has served as Vice PresidentlChiefScientist during this tame. He holds a B.Sc. in Applied Science from the Naval Acadt?my and an M.Sc. in Physics from the Naval Post Graduate School. He has cner 20 years experience in technical leadership material and personnel management. He has led the application of computer aided design (CAD) and Product Model Information Exchange to the shipbuilding industry. His experience also includes leading the amlication of model based operational analysis to support the Live Fire Test Program for DDG 51 Class Destroyers. Mr. Krishna M. Choppella:is a Sofware Engineer at Eidea Laboratories Incotporated where he works on componentbased distributed enterpvise frameworks. He has been involved in creating data analysis tools for the US Nay by integrating CAD modeis databases and graphical front ends. His work in the Masters degree program in Mechanical Engineering at the University of Texas at Austin was in di0ddase.r spectroscopy of combustion products in porous-matri burners. He received his Bachelors degree in Electrical Engineering in India. He was a Research Associate at the Centre for Laser Technology and Project Engi

Ship design is often multidisciplinary involving several design elements with various types of objectives and constraints (O/C) some easily described as mathematical formulas, others better modeled as descriptive assertions. This paper describes a method based on fuzzy functions and an integrated performance index to model O/C using descriptive assertions to be used with mathematical formulas in optimization. Another issue addressed in this paper concerns the coordination of design elements when sequentially coupled, that is, when one leads the other and the performance of the follower depends greatly on the design of the leader. Based on neuro-fuzzy techniques, the method described here coordinates and optimizes sequentially coupled elements. The two methods are applied to machinery arrangement (MA) and pipe routing (PR). Preliminary models for optimization of MA and PR are described considering convenience, producibility: engine room size, interference and location as factors in the O/C set. Some test results from MA/PR applications are presented and discussed. The methods are generic and can be extended to other elements in ship design. They are mutually independent and may be used separately Two advantages of their use are an improvement in overall performance and a reduction in the need for redesign of elements.

关键词： Optimization

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Characteristics and growth processes of a surface oxidized layer formed on Al-Y alloy films

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ELECTRONICS AND COMMUNICATIONS IN JAPAN PART II-ELECTRONICS 1996年第9期79卷 78-87页

作者： Takeyama, M Noya, A Murakami, Y Sasaki, K Faculty of Engineering Kitami Institute of Technology Kitami Japan 090 Education: Kitami Institute of Technology B.S. 1991. Academic appointments: Kitami Institute of Technology faculty member 1991 research associate 1993. Research interest: thin films for use in electronics. Membership: Applied Physics Society of Japan. Education: Muroran Institute of Technology B.S. 1974 Hokkaido University D.Eng. 1980. Academic appointments: Kitami Institute of Technology research associate (1980) lecturer (1990) associate professor (1991) professor (1994). Research interests: thin films especially in electronics and their evaluation. Membership: Applied Physics Society of Japan. Education: Kitami University of Technology B.S. 1994 master's degree in progress. Research interest: thin-film materials for electronics. Membership: Applied Physics Society of Japan. Education: Hokkaido University B.S. 1967 Hokkaido Institute of Electrical Engineering graduate program D.Eng. Academic appointments: Kitami Institute of Technology lecturer (1975) associate professor (1979) professor (1990). Research interests: thin-film materials for electronics electronic properties of materials LSI thin-film technology. Memberships: Applied Physics Society of Japan Japan Chemical Society.

The formation process as well as the characteristics of a surface oxidized layer formed on Al-Y alloy films are examined. Al in the alloy forms a thin Al2O3 layer due to more oxidation Pt the alloy surface. In an alloy of Al-rich composition, if the Al2O3 surface layer (which is comparable to that formed on pure Al) is formed, the layer maintains its ability to be a self-passivating oxide layer. In those alloys that form an unduly thin Al2O3 surface layer, introduction of oxygen from the ambient environment cannot be curtailed. As a result, oxidation proceeds and the formation of Y2O3 and reduced Al is observed within the oxide layer. In the oxidized layer, the oxidation state of the lesser amount of oxide is affected by that of the greater amount oxide;this reflects a shift in binding energy of the XPS spectra for the minor element. It is shown that the formation process of the alloy is dominated by the differences of ionization potential, an element affinity, formation heat, a diffusing species and the transport behavior of cations and/or anions.

关键词： Al-Y alloy films self-passivating oxide layer XPS spectra

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