排序方式: 共有12条查询结果,搜索用时 15 毫秒
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Santos MG Balbi A Borrill J Ferreira PG Hanany S Jaffe AH Lee AT Magueijo J Rabii B Richards PL Smoot GF Stompor R Winant CD Wu JH 《Physical review letters》2002,88(24):241302
We use the measurement of the cosmic microwave background taken during the MAXIMA-1 flight to estimate the bispectrum of cosmological perturbations. We propose an estimator for the bispectrum that is appropriate in the flat sky approximation, apply it to the MAXIMA-1 data, and evaluate errors using bootstrap methods. We compare the estimated value with what would be expected if the sky signal were Gaussian and find that it is indeed consistent, with a chi(2) per degree of freedom of approximately unity. This measurement places constraints on models of inflation. 相似文献
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Angle J Aprile E Arneodo F Baudis L Bernstein A Bolozdynya A Coelho LC Dahl CE DeViveiros L Ferella AD Fernandes LM Fiorucci S Gaitskell RJ Giboni KL Gomez R Hasty R Kastens L Kwong J Lopes JA Madden N Manalaysay A Manzur A McKinsey DN Monzani ME Ni K Oberlack U Orboeck J Plante G Santorelli R dos Santos JM Shagin P Shutt T Sorensen P Schulte S Winant C Yamashita M;XENON Collaboration 《Physical review letters》2008,101(9):091301
XENON10 is an experiment to directly detect weakly interacting massive particles (WIMPs), which may comprise the bulk of the nonbaryonic dark matter in our Universe. We report new results for spin-dependent WIMP-nucleon interactions with 129Xe and 131Xe from 58.6 live days of operation at the Laboratori Nazionali del Gran Sasso. Based on the nonobservation of a WIMP signal in 5.4 kg of fiducial liquid xenon mass, we exclude previously unexplored regions in the theoretically allowed parameter space for neutralinos. We also exclude a heavy Majorana neutrino with a mass in the range of approximately 10 GeV/c2-2 TeV/c2 as a dark matter candidate under standard assumptions for its density and distribution in the galactic halo. 相似文献
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A structural failure problem was solved using an integrated and iterative program of testing and analysis. The steps taken in solving the problem were: analytical calculations; operational testing; qualifications of analytical results; problem identification; design of corrective action; and confirmatory testing. 相似文献
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We have performed extensive small-angle neutron scattering (SANS) diffraction studies of the vortex lattice in single crystal
YNi2B2C for B‖c. High-resolution SANS, combined with a field-oscillation vortex lattice preparation technique, allows us to separate Bragg
scattered intensities from two orthogonal domains and accurately determine the unit cell angle, β. The data suggest that upon increasing field there is a finite transition width where both low- and high-field distorted
hexagonal vortex lattice phases, mutually rotated by 45°, coexist. The smooth variation of diffracted intensity from each
phase through the transition corresponds to a redistribution of populations between the two types of domains. 相似文献
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Angle J Aprile E Arneodo F Baudis L Bernstein A Bolozdynya A Brusov P Coelho LC Dahl CE DeViveiros L Ferella AD Fernandes LM Fiorucci S Gaitskell RJ Giboni KL Gomez R Hasty R Kastens L Kwong J Lopes JA Madden N Manalaysay A Manzur A McKinsey DN Monzani ME Ni K Oberlack U Orboeck J Plante G Santorelli R dos Santos JM Shagin P Shutt T Sorensen P Schulte S Winant C Yamashita M;XENON Collaboration 《Physical review letters》2008,100(2):021303
The XENON10 experiment at the Gran Sasso National Laboratory uses a 15 kg xenon dual phase time projection chamber to search for dark matter weakly interacting massive particles (WIMPs). The detector measures simultaneously the scintillation and the ionization produced by radiation in pure liquid xenon to discriminate signal from background down to 4.5 keV nuclear-recoil energy. A blind analysis of 58.6 live days of data, acquired between October 6, 2006, and February 14, 2007, and using a fiducial mass of 5.4 kg, excludes previously unexplored parameter space, setting a new 90% C.L. upper limit for the WIMP-nucleon spin-independent cross section of 8.8x10(-44) cm2 for a WIMP mass of 100 GeV/c2, and 4.5x10(-44) cm2 for a WIMP mass of 30 GeV/c2. This result further constrains predictions of supersymmetric models. 相似文献
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CD Bertram 《Contemporary Physics》2013,54(1):45-60
Collapsible tubes, which occur all over the body, have unique properties from the point of view of both physics and physiology. A brief review is attempted of first the basic observable properties, followed by simple theory to explain the steady-flow aspects and an overview of the somewhat more complex theories for unsteady flow, in particular the flow-induced oscillations. The experimental evidence from laboratory studies is reviewed with particular emphasis on the dynamical system aspects. A final section looks at the current position and prospects. 相似文献
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We have performed a series of neutron diffraction experiments from the magnetic order and the vortex lattice in single crystal
ErNi2B2C. The incommensurate magnetic structure develops additional even harmonics below the ‘ferromagnetic’ ordering temperature,
T
F of 2.3 K. This feature and the existence of rods of diffuse scattering suggest the development of ferromagnetic microdomain
walls. The magnetic structure is very sensitive to the application of a magnetic field with changes in modulation vector and
harmonic content. Studies of the vortex lattice show the presence of a 45° reorientation transition and a distorted hexagonal
to square transition as a function of applied field. Further distortions of the vortex lattice occur at T
N, but no changes are seen at T
F. 相似文献
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