检索结果-内蒙古大学图书馆

Weakly coupled motion of individual layers in ferromagnetic resonance

Physical Review B 2006年第6期74卷 064409-064409页

作者： D. A. Arena E. Vescovo C.-C. Kao Y. Guan W. E. Bailey Materials Science Program Department of Applied Physics Columbia University New York New York USA

We demonstrate a layer- and time-resolved measurement of ferromagnetic resonance (FMR) in a Ni81Fe19∕Cu∕Co93Zr7 trilayer structure. Time-resolved x-ray magnetic circular dichroism has been developed in transmission, with resonant field excitation at a FMR frequency of 2.3GHz. Small-angle (to 0.2°), time-domain magnetization precession could be observed directly, and resolved to individual layers through elemental contrast at Ni, Fe, and Co edges. The phase sensitivity allowed direct measurement of relative phase lags in the precessional oscillations of individual elements and layers. A weak ferromagnetic coupling, difficult to ascertain in conventional FMR measurements, is revealed in the phase and amplitude response of individual layers across resonance.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Fabrication of Nanoparticles and Microspheres with Uniform Magnetic Half-Shells

引用

MRS Online Proceedings Library 2006年第1期899卷 1-9页

作者： Brandon H. McNaughton Vladimir A. Stoica Jeffrey N. Anker Katherine M.Tyner Roy Clarke Raoul Kopelman Department of Chemistry The University of Michigan Ann Arbor USA Applied Physics Program The University of Michigan Ann Arbor USA The University of Michigan Toxicology Program Ann Arbor USA

We report a method for fabricating, anisotropically designed, multiphasic nano-particles with uniform magnetic half-shells. Cobalt layers were deposited onto commercially made non-magnetic polystyrene nanospheres and microspheres, using ultrahigh vacuum vapor deposition, which produced particles with a half-shell of uniform size, shape and magnetic content. Iron was also deposited onto commercially made silica nanospheres and microspheres and was characterized using transmission electron microscopy and scanning electron microscopy. The coercivity of the magnetic material layers, on the substrate-supported spheres, was enhanced compared to the bulk values of such films without spheres. The particles, once removed from the substrate, were amenable to being rotated in solution, which could allow for more accurate physical and chemical measurements in a variety of fluidic environments. Applications for imaging local mechanical, magnetic and electrical environments are also delineated.

关键词： ferromagnetic nanostructure nanoscale

来源：评论

学校读者我要写书评

暂无评论

ENSO and genesis potential index in reanalysis and AGCMS

ENSO and genesis potential index in reanalysis and AGCMS

引用

27th Conference on Hurricanes and Tropical Meteorology

作者： Camargo, Suzana J. Emanuel, Kerry A. Sobel, Adam H. International Research Institute for Climate and Society Columbia Earth Institute Palisades NY United States Program in Atmospheres Oceans and Climate Massachusetts Institute of Technology Cambridge MA United States Department of Applied Physics and Applied Mathematics Department of Earth and Environmental Sciences Columbia University New York NY United States

来源：评论

学校读者我要写书评

暂无评论

Sea surface temperature signatures of oceanic internal waves in low winds

Sea surface temperature signatures of oceanic internal waves...

引用

27th Conference on Hurricanes and Tropical Meteorology

作者： Farrar, J. Tom Zappa, Christopher Weller, Robert Jessup, Andrew T. MIT-WHOI Joint Program in Physical Oceanography United States Lamont-Doherty Earth Observatory Columbia University United States Woods Hole Oceanographic Institution United States University of Washington Applied Physics Laboratory United States

In aerial surveys conducted during the Tropical Ocean-Global Atmosphere (TOGA) Coupled Ocean-Atmosphere Response Experiment (COARE) and the low wind component of the Coupled Boundary Layer Air-Sea Transfer (CBLAST-Low) oceanographic field programs, sea surface temperature (SST) variability at relatively short spatial scales (10's of meters to kilometers) has been observed to increase under low wind conditions. A unique data set of coincident surface and subsurface oceanic temperature measurements is used to investigate the subsurface expression of this spatially organized sea surface temperature variability, and it is shown that the SST signal is associated with oceanic internal waves. The data are used to test the two previously hypothesized mechanisms for SST signatures of oceanic internal waves: that internal wave signals in SST are caused by modulation of the cool-skin effect and that signals are caused by modulation of vertical mixing within the diurnal warm-layer. Under conditions of weak winds and strong insolation (which favor formation of a diurnal warm-layer), the data reveal a strong link between the spatially periodic SST fluctuations and subsurface temperature and velocity fluctuations associated with oceanic internal waves, suggesting that some mechanism involving the diurnal warm-layer is responsible for the observed internal wave signal. The lack of a clear internal wave signal in SST when no warm layer is present further suggests that the cool-skin straining may not be as effective a mechanism for producing internal wave signals in SST.

关键词： Surface temperature

来源：评论

学校读者我要写书评

暂无评论

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

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

引用

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

来源：评论

学校读者我要写书评

暂无评论

Time-resolved reflectance of two-layered tissue models via scaling of "White" monte carlo simulations

Time-resolved reflectance of two-layered tissue models via s...

引用

Biomedical Topical Meeting, BIO 2006

作者： Wilson, Robert H. Vishwanath, Karthik Mycek, Mary-Ann Department of Physics Ann Arbor MI 48109-2099 United States Department of Biomedical Engineering Ann Arbor MI 48109-2099 United States Applied Physics Program Ann Arbor MI 48109-2099 United States Comprehensive Cancer Center University of Michigan Ann Arbor MI 48109-2099 United States

Absorption-scaling methods were applied to Monte Carlo simulations of two-layered tissues by incorporating a path integral (PI) formalism. Times spent by photons in the top-layer can be significantly underestimated wh... 详细信息

ISBN: (纸本)1557528071

关键词： Monte Carlo methods

来源：评论

学校读者我要写书评

暂无评论

Algorithm-based analysis of collective decoherence in quantum search

引用

Progress in Informatics 2006年第3期 5-18页

作者： Master, Cyrus P. Utsunomiya, Shoko Yamamoto, Yoshihisa National Institute of Informatics Tokyo Japan E.L. Ginzton Laboratory Stanford University Stanford CA Department of Information and Communication Engineering University of Tokyo Tokyo Japan National Institute of Informatics Stanford University University of Tokyo Stanford University Applied Physics and Electrical Engineering National Institute of Informatics NTT R and D JST CREST Program on Quantum Information

A major challenge in the implementation of quantum computers is mitigating the impact of undesired couplings with the environment that lead to decoherence. Here, we discuss an error-avoiding strategy that is based upon freedoms inherent in decomposing a quantum algorithm into fundamental gates. Although this approach is specific to a particular algorithm and a collective noise model, it does not the require complicated encodings or significant additional qubit resources of more general error-correcting codes. This paper also includes an overview of quantum computation, including a discussion of the quantum search algorithm. © 2006 National Instiute of Informatics.

关键词： Quantum theory

来源：评论

学校读者我要写书评

暂无评论

Integrated semiconductor optical sensors for chronic, minimally-invasive imaging of brain function

Integrated semiconductor optical sensors for chronic, minima...

引用

28th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS'06

作者： Lee, Thomas T. Levi, Ofer Jianhua, Cang Kaneko, Megumi Stryker, Michael P. Smith, Stephen J. Shenoy, Krishna V. Harris Jr., James S. IEEE Department of Electrical Engineering Stanford University Stanford CA 94303 United States Departments of Electrical Engineering and Applied Physics Stanford University Stanford CA 94305 United States Department of Physiology University of California San Francisco 94143 United States Department of Molecular and Cellular Physiology Neurosciences Program Stanford University Stanford CA 94305 United States Department of Electrical Engineering Neurosciences Program Stanford University Stanford CA 94305 United States Departments of Electrical Engineering Applied Physics and Materials Science and Engineering Stanford University Stanford CA 94305 United States

ISBN: (纸本)1424400325

Intrinsic Optical Signal (IOS) imaging is a widely accepted technique for imaging brain activity. We propose an integrated device consisting of interleaved arrays of gallium arsenide (GaAs) based semiconductor light sources and detectors operating at telecommunications wavelengths in the near-infrared. Such a device will allow for long-term, minimally invasive monitoring of neural activity in freely behaving subjects, and will enable the use of structured illumination patterns to improve system performance. In this work we describe the proposed system and show that near-infrared IOS imaging at wavelengths compatible with semiconductor devices can produce physiologically significant images in mice, even through skull. © 2006 IEEE.

关键词： Optical sensors

来源：评论

学校读者我要写书评

暂无评论

Planning for an integrated M&S framework for catastrophic event response

Planning for an integrated M&S framework for catastrophic ev...

引用

Spring Simulation Interoperability Workshop 2007, 07 Spring SIW

作者： Coolahan, James E. Applied Physics Laboratory National Security Analysis Department Johns Hopkins University 11100 Johns Hopkins Road Laurel MD United States Committee United States United States Forum SISO United States Research Development and Engineering Forum Program United States

ISBN: (纸本)9781604239232

In late 2005, the U.S. Department of Homeland Security (DHS) selected a multi-University consortium led by the Johns Hopkins University (JHU) to form a University Center of Excellence (UCE) focused on the study of Preparedness and Catastrophic Event Response (PACER). One of the initial three-year cross-cutting projects being performed under the PACER UCE is the construction of an initial integrated M&S framework focused on preparing for the response to catastrophic events. This project, started in the fall of 2006, is led by the applied physics Laboratory of JHU (JHU/APL), and involves researchers from the University of Alabama Birmingham (UAB), Florida Atlantic University (FAU), Florida A&M University (FAMU), and the Brookings Institution. After an initial effort to catalog the variety of models and simulations appropriate to this area of study, the project will establish two prototype federations based on the High Level Architecture (HLA) - an Urban Chemical Disaster federation to be constructed in 2007-08, and a Bioterrorism Crisis Management federation to be constructed in 2008- 09. Ultimately, the M&S framework is intended to provide a composable set of simulations that can be used as an aid to decision-makers in training/rehearsal for responses to catastrophic events. This paper will outline the plans for the integrated M&S framework project, focusing on the design of the initial Urban Chemical Disaster prototype federation, the definition of its initial scenario of interest, and the focus areas of the simulations to be employed in the federation, to include airborne chemical transport and traffic flow simulation.

关键词： National security

来源：评论

学校读者我要写书评

暂无评论

Enhancement of light extraction in gainn light-emitting diodes by conductive omni-directional reflectors

Enhancement of light extraction in gainn light-emitting diod...

引用

Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference, CLEO/QELS 2006

作者： Kim, Jong Kyu Xi, J.-Q. Luo, Hong Schubert, E. Fred Cho, Jaehee Sone, Cheolsoo Park, Yongjo Electrical Computer and Systems Engineering Dept. Rensselaer Polytechnic Institute 110 Eighth St. Troy NY 12180 United States Dept. of Physics Applied Physics and Astronomy Rensselaer Polytechnic Institute 110 Eighth St. Troy NY 12180 United States Photonics Program Team Samsung Advanced Institute of Technology Suwon 440-600 Korea Republic of

Enhancement of light extraction in a GaInN light-emitting diode employing a conductive omnidirectional reflector consisting of GaN, an indium-tin oxide nanorod low-refractive-index layer, and an Ag layer is presented.... 详细信息

ISBN: (纸本)1557528136

关键词： Light emitting diodes

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：