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排序方式: 共有92条查询结果,搜索用时 15 毫秒
1.
Lazarus EA Navratil GA Greenfield CM Strait EJ Austin ME Burrell KH Casper TA Baker DR DeBoo JC Doyle EJ Durst R Ferron JR Forest CB Gohil P Groebner RJ Heidbrink WW Hong R Houlberg WA Howald AW Hsieh C Hyatt AW Jackson GL Kim J Lao LL Lasnier CJ Leonard AW Lohr J La Haye RJ Maingi R Miller RL Murakami M Osborne TH Perkins LJ Petty CC Rettig CL Rhodes TL Rice BW Sabbagh SA Schissel DP Scoville JT Snider RT Staebler GM Stallard BW Stambaugh RD St John HE Stockdale RE Taylor PL Thomas DM 《Physical review letters》1996,77(13):2714-2717
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Miyazaki A Fujisawa Y Shiotani K Fujita Y Li T Tsuda Y Yokoi T Bryant SD Lazarus LH Okada Y 《Chemical & pharmaceutical bulletin》2005,53(9):1152-1158
1,2-Dihydropyrazin-2-one derivatives, which have two aminoalkyl groups at the positions 3 and 6, were found to be efficient tools for the construction of potent, selective and long-acting opioid mimetics. During the course of preparation, we found that the catalytic hydrogenation of 3,6-bis(benzyloxycarbonylaminomethyl)-5-methyl-1,2-dihydropyrazin-2-one to remove the benzyloxycarbonyl groups resulted in a side reaction. By MS and NMR studies and by preparation of additional 1,2-dihydropyrazin-2-one derivatives, the structure of the by-product was identified as 3-aminomethyl-5,6-dimethyl-1,2-dihydropyrazin-2-one. Preparation of additional compounds substituted with deuterium provided us with sufficient information to confirm the structure of the product and to support a cyclization mechanism in its formation. 相似文献
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J. -E. Augustin G. Cosme F. Couchot B. Dudelzak F. Fulda B. Grelaud G. Grosdidier B. Jean-Marie S. Jullian D. Lalanne V. Lepeltier B. Louis F. Mané C. Paulot R. Riskalla Ph. Roy F. Rumpf G. Szklarz Z. Ajaltouni A. Falvard J. Jousset B. Michel J. C. Montret R. Baldini S. Calcaterra G. Capon D. Bisello G. Busetto S. Limentani M. Nigro L. Pescara M. Posocco P. Sartori L. Stanco DM Collaboration 《Zeitschrift fur Physik C Particles and Fields》1987,36(3):369-376
The radiative decayJ/ψ → γ π+ π? has been studied using the 8.6 millionJ/ψ produced in the DM2 experiment at the DCIe +e? storage rings at Orsay. The π+ π? mass spectrum shows a cleanf 2 (1270) signal, and the possible presence of two other states at thef 2 (1720) andf 4 (2030) masses. For thef 2 (1270), the branching ratio BR(J/ψ →γf)xBR(f→π+ π?) is measured to be (7.50±0.30±1.12)×10?4, and the spin analysis prefers theJ=2 assignment, with helicity parametersx=0.83±0.06 andy=0.01±0.06. The existence of higher mass states is discussed. 相似文献
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Brynne E. Lazarus Matthew J. Germino Jessica L. Vander Veen 《Isotopes in environmental and health studies》2016,52(3):309-325
Application of stable isotopes of water to studies of plant–soil interactions often requires a substantial preparatory step of extracting water from samples without fractionating isotopes. Online heating is an emerging approach for this need, but is relatively untested and major questions of how to best deliver standards and assess interference by organics have not been evaluated. We examined these issues in our application of measuring woody stem xylem of sagebrush using a Picarro laser spectrometer with online induction heating. We determined (1) effects of cryogenic compared to induction-heating extraction, (2) effects of delivery of standards on filter media compared to on woody stem sections, and (3) spectral interference from organic compounds for these approaches (and developed a technique to do so). Our results suggest that matching sample and standard media improves accuracy, but that isotopic values differ with the extraction method in ways that are not due to spectral interference from organics. 相似文献
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Let G be the graph of a triangulated surface \(\varSigma \) of genus \(g\ge 2\). A cycle of G is splitting if it cuts \(\varSigma \) into two components, neither of which is homeomorphic to a disk. A splitting cycle has type k if the corresponding components have genera k and \(g-k\). It was conjectured that G contains a splitting cycle (Barnette 1982). We confirm this conjecture for an infinite family of triangulations by complete graphs but give counter-examples to a stronger conjecture (Mohar and Thomassen in Graphs on surfaces. Johns Hopkins studies in the mathematical sciences. Johns Hopkins University Press, Baltimore, 2001) claiming that G should contain splitting cycles of every possible type. 相似文献
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Erin W. Chambers ric Colin de Verdire Jeff Erickson Francis Lazarus Kim Whittlesey 《Computational Geometry》2008,41(1-2):94
Let be an orientable combinatorial surface. A cycle on is splitting if it has no self-intersections and it partitions into two components, neither of which is homeomorphic to a disk. In other words, splitting cycles are simple, separating, and non-contractible. We prove that finding the shortest splitting cycle on a combinatorial surface is NP-hard but fixed-parameter tractable with respect to the surface genus g and the number of boundary components b of the surface. Specifically, we describe an algorithm to compute the shortest splitting cycle in (g+b)O(g+b)nlogn time, where n is the complexity of the combinatorial surface. 相似文献
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N. Pindra V. Lazarus J.-B. Leblond 《Journal of the mechanics and physics of solids》2010,58(3):281-3503
A statistical analysis of the deformation of the fronts of a tensile tunnel-crack propagating in fatigue in some medium with spatially varying Paris constant was recently performed, with special emphasis on the evolution of the power spectra and correlation functions of the fluctuations of the fronts around reference straight lines. This study is extended here to coplanar propagation (along a weak plane) of a tunnel-crack loaded in mode 2+3. The results are rather similar to those previously obtained for mode 1. In particular, just like for tensile loadings, there is an effect of gradual selection in time of Fourier components of the fluctuations of the fronts of large wavelength. One novelty, however, is that for shear loadings, the fronts no longer tend to become symmetrical in time, so that correlations between crack front fluctuations at two points are higher for points located on the same front than for points located on distinct ones. 相似文献