排序方式: 共有35条查询结果,搜索用时 15 毫秒
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D. Bisello G. Busetto A. Castro M. Nigro M. Penzo L. Pescara M. Posocco P. Sartori L. Stanco Z. Ajaltouni A. Falvard J. Jousset B. Michel J. C. Montret A. Antonelli R. Baldini A. Calcaterra G. Capon M. Schioppa J. -E. Augustin G. Cosme F. Couchot B. Dudelzak F. Fulda G. Grosdidier B. Jean-Marie S. Jullian D. Lalanne V. Lepeltier F. Manè C. Paulot R. Riskalla Ph. Roy G. Szklarz DM Collaboration 《Zeitschrift fur Physik C Particles and Fields》1988,39(1):13-19
Thee + e ?→K + K ? cross section has been measured from about 750 events in the energy interval \(1350 \leqq \sqrt s \leqq 2400 MeV\) with the DM2 detector at DCI. TheK ± form factor |F F ±| cannot be explained by the ρ, ω, ? and ρ′(1600). An additional resonant amplitude at 1650 MeV has to be added as suggested by a previous experiment. 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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The steady propagation of a thin smouldering front in a half-spacehas been considered. A suitable coordinate transformation hasallowed the region near the leading edge of the front to beexamined for both a maintained planar surface and with surfacecollapse due to material shrinkage. The change in the oxidizerconcentration for a small increment in the propagation speedfor large time and surface collapse has been determined. Theinfluence of two types of nonlinear diffusion on the shape ofthe smouldering front has been found; other cases can be dealtwith in a similar manner. 相似文献
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Timothy Atallah Ronald L. Blankespoor Philip Homan Chase Hulderman Brian M. Samas Kurt Van Allsburg Derek C. Vrieze 《Tetrahedron letters》2013
In the presence of commercially available chiral rhodium catalysts, a competitive benzylamination of racemic allyl carbonates, substituted with p-X-Ph groups, shows that the reaction proceeds faster with substituents (X) that are more electron-withdrawing. Mechanistic implications of these results are discussed. 相似文献
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N. M. Homan C. W. Windt F. J. Vergeldt E. Gerkema H. Van As 《Applied magnetic resonance》2007,32(1-2):157-170
Dedicated magnetic resonance imaging (MRI) hardware is described that allows imaging of sap flow in intact trees with a maximal
trunk diameter of 4 cm and height of several meters. This setup is used to investigate xylem and phloem flow in an intact
tree quantitatively. Due to the fragile gradients in pressure present in both xylem and phloem, methods to study xylem and
phloem transport must be minimally invasive. MRI flow imaging by means of this hardware certainly fulfils this condition.
Flow is quantified in terms of (averaged) velocity, volume flow (flux) and flow conducting area, either in imaging mode or
as a nonspatially resolved total. Results obtained for one tree, imaged at two different field strengths (0.7 and 3 T), are
compared. An overall shortening of observed T
2 values is manifest going from 0.7 to 3 T. Although some susceptibility artefacts may be present at 3 T, the results are still
reliable and the gain in sensitivity results in shorter measurement time (or higher signal-to-noise ratio) with respect to
the 0.7 T system. The results demonstrate that by use of dedicated hardware, xylem and phloem flow and its mutual interaction,
can be studied in intact trees in relation to the water balance and in response to environmental (stress) conditions.
Authors' address: Henk Van As, Laboratory of Biophysics, Wageningen University, Drejenlaan 3, 6703 HA Wageningen, The Netherlands 相似文献
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Homan EA Kim YG Cardia JP Saghatelian A 《Journal of the American Chemical Society》2011,133(14):5178-5181
The molecular mechanisms that lead to the generation of adipose tissue (adipogenesis) are of basic and biomedical interest. Cellular models of adipogenesis have proven extremely valuable in defining biomolecules-primarily genes and proteins-that regulate adipogenesis. Here, the analysis of differentiating adipocytes using an untargeted metabolomics approach led to the discovery of the monoalkylglycerol ethers as a natural class of adipocyte differentiation factors. 相似文献