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81.
Jaudet C Vignolles D Audouard A Levallois J LeBoeuf D Doiron-Leyraud N Vignolle B Nardone M Zitouni A Liang R Bonn DA Hardy WN Taillefer L Proust C 《Physical review letters》2008,100(18):187005
The de Haas-van Alphen effect was observed in the underdoped cuprate YBa2Cu3O6.5 via a torque technique in pulsed magnetic fields up to 59 T. Above a field of approximately 30 T the magnetization exhibits clear quantum oscillations with a single frequency of 540 T and a cyclotron mass of 1.76 times the free electron mass, in excellent agreement with previously observed Shubnikov-de Haas oscillations. The oscillations obey the standard Lifshitz-Kosevich formula of Fermi-liquid theory. This thermodynamic observation of quantum oscillations confirms the existence of a well-defined, closed, and coherent, Fermi surface in the pseudogap phase of cuprates. 相似文献
82.
A. Prévost N. Buforn A. Astier R. Duffait M. Meyer S. Perriès N. Redon O. Stézowski A. Bauchet I. Deloncle M.G. Porquet A. Görgen H. Hübel E. Mergel S. Neumann D. Roßbach N. Nenoff G. Schönwaßer A.N. Wilson R. Lucas F.A. Beck D. Curien G. Duchêne B.J.P. Gall N. Kintz J.P. Vivien D.M. Cullen 《The European Physical Journal A - Hadrons and Nuclei》2001,10(1):13-19
We report the identification of six new superdeformed (SD) bands in 197,198Pb observed with the EUROBALL IV spectrometer. The results are interpreted in the framework of cranked Hartree-Fock calculations
with approximate projection on the particle number by means of the Lipkin-Nogami method. A mixing between quasi-particle excitations
and an octupole vibration is suggested in the two SD isotopes. We have estimated the ordering of the neutron valence orbitals
and confirm indirectly a N = 118 SD gap.
Received: 20 December 2000 / Accepted: 24 January 2001 相似文献
83.
M. -G. Porquet A. Astier Ts. Venkova A. Prévost I. Deloncle F. Azaiez A. Buta D. Curien O. Dorvaux G. Duchêne B. J. P. Gall F. Khalfallah I. Piqueras M. Rousseau M. Meyer N. Redon O. Stézowski R. Lucas A. Bogachev 《The European Physical Journal A - Hadrons and Nuclei》2009,39(3):295-306
The 81, 82, 83, 85Se nuclei have been produced as fission fragments in the fusion reaction 18O + 208Pb at 85MeV bombarding energy and studied with the Euroball IV array. Their high-spin level schemes have been built from the
triple -ray coincidence data and - angular correlations have been analyzed in order to assign spin and parity values to many observed states. The lowest-spin
states of the two-neutron and three-neutron configurations are strongly mixed with two-proton excitations among the fp orbits. On the other hand, the highest-spin states of these neutron configurations are found to remain almost pure. Neutron
excitation across the N = 50 gap is observed both in 83Se49 and in 85Se51 . 相似文献
84.
Alain Escassut 《Journal of Number Theory》1983,16(3):395-402
Let (K, ∥ · ∥) be a valued transcendence degree 1 extension of p. An element x ∈ K transcendental over p is said to have order ≤a (a > 0) if there exists Cx > 0 such that every polynomial P(X) ∈ p [X] satisfies when ∥ · ∥ is the Gauss norm on p[X]. No x ∈ p can have order ≤α if α < 1 but we construct some x ∈ p with order ≤ 1. Furthermore, we prove order ≤α is stable by algebraic extension. 相似文献
85.
J. B. Natowitz S. Leray R. Lucas C. Ngô E. Tomasi C. Volant 《Zeitschrift für Physik A Hadrons and Nuclei》1986,325(4):467-474
A simple formula based on leading particle models of nucleon-nucleon collisions is used to evaluate the average momentum transfer in central heavy ion collisions at energies from 20 to 150 MeV/u. This formula, which reproduces a number of the features of the observed systematics, offers a straightforward explanation for the approximate universality of fractional linear momentum transfer as a function of velocity, the dependence of fractional momentum transfer on target mass and the greater fractional momentum transfer of the proton as compared to heavy ion projectiles. 相似文献
86.
87.
Jean-Loïc Rose Alain Lalande Olivier Bouchot El-Bey Bourennane Paul M. Walker Patricia Ugolini Chantal Revol-Muller Raymond Cartier François Brunotte 《Magnetic resonance imaging》2010
Magnetic resonance imaging (MRI) is particularly well adapted to the evaluation of aortic distensibility. The calculation of this parameter, based on the change in vessel cross-sectional area per unit change in blood pressure, requires precise delineation of the aortic wall on a series of cine-MR images. Firstly, the study consisted in validating a new automatic method to assess aortic elasticity. Secondly, aortic distensibility was studied for the ascending and descending thoracic aortas in 26 healthy subjects. Two homogeneous groups were available to evaluate the influence of sex and age (with an age limit value of 35 years). The automatic postprocessing method proved to be robust and reliable enough to automatically determine aortic distensibility, even on artefacted images. In the 26 healthy volunteers, a marked decrease in distensibility appears with age, although this decrease is only significant for the ascending aorta (8.97±2.69 10−3 mmHg−1 vs. 5.97±2.02 10−3 mmHg−1). Women have a higher aortic distensibility than men but only significantly at the level of the descending aorta (7.20±1.61 10−3 mmHg−1 vs. 5.05±2.40 10−3 mmHg−1). Through our automatic contouring method, the aortic distensibility from routine cine-MRI has been studied on a healthy subject population providing reference values of aortic stiffness. The aortic distensibility calculation shows that age and sex are causes of aortic stiffness variations in healthy subjects. 相似文献
88.
Lucas C. Wilcox Georg Stadler Carsten Burstedde Omar Ghattas 《Journal of computational physics》2010,229(24):9373-9396
We introduce a high-order discontinuous Galerkin (dG) scheme for the numerical solution of three-dimensional (3D) wave propagation problems in coupled elastic–acoustic media. A velocity–strain formulation is used, which allows for the solution of the acoustic and elastic wave equations within the same unified framework. Careful attention is directed at the derivation of a numerical flux that preserves high-order accuracy in the presence of material discontinuities, including elastic–acoustic interfaces. Explicit expressions for the 3D upwind numerical flux, derived as an exact solution for the relevant Riemann problem, are provided. The method supports h-non-conforming meshes, which are particularly effective at allowing local adaptation of the mesh size to resolve strong contrasts in the local wavelength, as well as dynamic adaptivity to track solution features. The use of high-order elements controls numerical dispersion, enabling propagation over many wave periods. We prove consistency and stability of the proposed dG scheme. To study the numerical accuracy and convergence of the proposed method, we compare against analytical solutions for wave propagation problems with interfaces, including Rayleigh, Lamb, Scholte, and Stoneley waves as well as plane waves impinging on an elastic–acoustic interface. Spectral rates of convergence are demonstrated for these problems, which include a non-conforming mesh case. Finally, we present scalability results for a parallel implementation of the proposed high-order dG scheme for large-scale seismic wave propagation in a simplified earth model, demonstrating high parallel efficiency for strong scaling to the full size of the Jaguar Cray XT5 supercomputer. 相似文献
89.
Christabel E. Fowler Catherine Buchber Joël Patarin Alain Walcarius 《Applied Surface Science》2007,253(12):5485-5493
Diatomaceous earth was functionalized by grafting organotrialkoxysilane precursors onto the surface of the porous silica cell walls of this biomineral. Vinyl- and mercapto-containing structures were prepared in aqueous media without disruption of the diatomic architecture. Successful grafting of the organic moieties was confirmed using solid state 29Si MAS NMR spectroscopy, and the presence of the intact diatom framework by scanning electron microscopy. The sorption properties of mercaptopropyl-functionalized diatoms towards heavy metals was studied by measuring the accessibility and diffusion rates of mercury(II) species to the binding sites (-SH) by the means of electrochemical methods. 相似文献
90.
Bernard Masereel Mustapha Dinguizli Caroline Bouzin Nicolas Moniotte Olivier Feron Bernard Gallez Thierry Vander Borght Carine Michiels Stéphane Lucas 《Journal of nanoparticle research》2011,13(4):1573-1580
Nanoscale materials are used in the biomedical field for magnetic resonance imaging, protein detection and drug/gene delivery.
Gold nanoparticles (AuNPs) are particularly investigated in cancer treatment and imaging. In this study, we described a simple
and reliable liquid method to coat AuNPs (diameter: 21 nm) layer-by-layer with alternative cationic polyallylamine and anionic
polystyrenesulfonate. The C-terminal amino acid of the antibody directed against anti-bovine serum albumin was activated by
EDC/NHS, and then condensed with the amino functions of the external polyallylamine layer. An ELISA test confirmed that the
antigen recognition of the bioconjugate antibody was conserved. This AuNP coating and the covalently coupling could be used
as a generic process for binding other specific antibodies, particularly those overexpressed in cancer cells and angiogenesis. 相似文献