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排序方式: 共有411条查询结果,搜索用时 15 毫秒
221.
S. Girard I. Trenteseaux Y. Ouerdane J-P Meunier A. Boukenter J-L. Derep L. Thonnérieux 《光学学报》2003,23(Z1)
A new method to determine the radial distribution of attenuation in single-mode optical fibers is proposed. As an example, radiation-induced losses in gamma-irradiated germanosilicate fibers are characterized at 633 nm. 相似文献
222.
Olivier Durand de Gevigney Fr��d��ric Meunier Christian Popa Julien Reygner Ayrin Romero 《4OR: A Quarterly Journal of Operations Research》2011,9(2):175-188
Let T = (V, A) be a directed tree. Given a collection P{\mathcal{P}} of dipaths on T, we can look at the arc-intersection graph I(P,T){I(\mathcal{P},T)} whose vertex set is P{\mathcal{P}} and where two vertices are connected by an edge if the corresponding dipaths share a common arc. Monma and Wei, who started
their study in a seminal paper on intersection graphs of paths on a tree, called them DE graphs (for directed edge path graphs)
and proved that they are perfect. DE graphs find one of their applications in the context of optical networks. For instance,
assigning wavelengths to set of dipaths in a directed tree network consists in finding a proper coloring of the arc-intersection
graph. In the present paper, we give
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a simple algorithm finding a minimum proper coloring of the paths. 相似文献
223.
Graphitic nanowiggles (GNWs) are periodic repetitions of nonaligned finite-sized graphitic nanoribbon domains seamlessly stitched together without structural defects. These complex nanostructures have been recently fabricated [Cai et al., Nature (London) 466, 470 (2010)] and are here predicted to possess unusual properties, such as tunable band gaps and versatile magnetic behaviors. We used first-principles theory to highlight the microscopic origins of the emerging electronic and magnetic properties of the main subclasses of GNWs. Our study establishes a road map for guiding the design and synthesis of specific GNWs for nanoelectronic, optoelectronic, and spintronic applications. 相似文献
224.
Nadia Brauner Sylvain Gravier Louis-Philippe Kronek Frédéric Meunier 《Discrete Applied Mathematics》2013,161(7-8):909-920
Motivated by applications of Logical Analysis of Data (LAD) in medical contexts, original discrete optimization problems are proposed. When a patient arrives with a presumption of a disease, he is submitted to a sequence of tests. From one patient to another, the tests allowing to detect the disease may vary. A subset of tests whose results detect the disease in a given part of the population is called a pattern, which has its own prevalence in the population.If there is only a limited number of tests that can be done, which ones must be selected in order to maximize the number of spotted patients? Or, if each test has a cost, in which order the tests have to be done, in order to minimize the cost? It is the kind of questions that are investigated in this paper. For various special cases, polynomial algorithms are proposed, especially when the hypergraph whose vertices are the tests and whose edges are the patterns is a tree graph.One of these questions involves a criterion which is not a number but a sequence of numbers. The objective is then to find the best sequence for the lexicographic order. To solve this question, a new product on finite sequences is defined, namely the maximum shuffle product, which maps two sequences to their shuffle that is maximal for the lexicographic order. Surprisingly, this product leads to a theorem similar to the fundamental theorem of arithmetic: every sequence can be written uniquely as the product of prime sequences, with the suitable definition of prime sequences. 相似文献
225.
Jérôme Boissier Julien Portela Vincent Pradines Frédéric Coslédan Anne Robert Bernard Meunier 《Comptes Rendus Chimie》2012,15(1):75-78
Schistosomiasis is a chronic life-threatening parasitic disease concerning more than 200 million people in the World. Little attention has been paid to schistosomiasis over the last 30 years, and praziquantel is the only drug in use to control this disease. In the absence of a vaccine, there is a real need for new drugs in order both to improve the efficacy of the treatment and to delay the development of praziquantel resistant schistosomes. The present note reports the significant reduction of the worm burden after oral administration of trioxaquine PA1259 to mice infected by Schistosoma mansoni. 相似文献
226.
Xavier Carton Thomas Meunier Glenn R. Flierl Xavier Perrot Mikhail A. Sokolovskiy 《Theoretical and Computational Fluid Dynamics》2010,24(1-4):131-135
In a two-layer quasi-geostrophic model, a baroclinic vortex is submitted to a periodic forcing of its mean baroclinic azimuthal velocity. It is shown that parametric effects could stabilize a vortex which is baroclinically unstable in the absence of forcing. Conversely, parametric resonance can destabilize a baroclinically stable vortex, under conditions on the vortex parameters, on the ratio of layer thicknesses or on the forcing frequency. 相似文献
227.
228.
Akerib DS Attisha MJ Bailey CN Baudis L Bauer DA Brink PL Brusov PP Bunker R Cabrera B Caldwell DO Chang CL Cooley J Crisler MB Cushman P Daal M Dixon R Dragowsky MR Driscoll DD Duong L Ferril R Filippini J Gaitskell RJ Golwala SR Grant DR Hennings-Yeomans R Holmgren D Huber ME Kamat S Leclercq S Lu A Mahapatra R Mandic V Meunier P Mirabolfathi N Nelson H Nelson R Ogburn RW Perera TA Pyle M Ramberg E Rau W Reisetter A Ross RR Sadoulet B Sander J Savage C Schnee RW Seitz DN Serfass B 《Physical review letters》2006,96(1):011302
We report new results from the Cryogenic Dark Matter Search (CDMS II) at the Soudan Underground Laboratory. Two towers, each consisting of six detectors, were operated for 74.5 live days, giving spectrum-weighted exposures of 34 (12) kg d for the Ge (Si) targets after cuts, averaged over recoil energies 10-100 keV for a weakly interacting massive particle (WIMP) mass of 60 GeV/c2. A blind analysis was conducted, incorporating improved techniques for rejecting surface events. No WIMP signal exceeding expected backgrounds was observed. When combined with our previous results from Soudan, the 90% C.L. upper limit on the spin-independent WIMP-nucleon cross section is 1.6 x 10(-43) cm2 from Ge and 3 x 10(-42) cm2 from Si, for a WIMP mass of 60 GeV/c2. The combined limit from Ge (Si) is a factor of 2.5 (10) lower than our previous results and constrains predictions of supersymmetric models. 相似文献
229.
Carathéodory’s, Helly’s and Radon’s theorems are three basic results in discrete geometry. Their max-plus or tropical analogues
have been proved by various authors. We show that more advanced results in discrete geometry also have max-plus analogues,
namely, the colorful Carathéodory theorem and the Tverberg theorem. A conjecture connected to the Tverberg theorem—Sierksma’s
conjecture—although still open for the usual convexity, is shown to be true in the max-plus setting. 相似文献
230.
The paper deals with σ-games on grid graphs (in dimension 2 and more) and conditions under which any completely symmetric configuration of lit vertices
can be reached – in particular the completely lit configuration – when starting with the all-unlit configuration. The answer
is complete in dimension 2. In dimension ≥3, the answer is complete for the σ
+-game, and for the σ
−-game if at least one of the sizes is even. The case σ
−, dimension ≥3 and all sizes odd remains open. 相似文献
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