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1.
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
5.
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
6.
The first synthesis of “α-methylene-γ-phostones” (propylphostonates) using dimethyl bromo-3-propen-2 ylphosphonate and ketones and aldehydes, in the presence of zinc, is described. 相似文献
7.
Christophe Collard Bernadette Miara 《Archive for Rational Mechanics and Analysis》1999,148(3):233-264
. In this paper, we identify the limiting stress tensor of a thin elastic shell whose thickness approaches zero. In the linear
case, we use a convergence result established for the displacement field in order to get the convergence of the contravariant
components of the linearised stress tensor. In the nonlinear case, the identification of the first Piola‐Kirchhoff stress
tensor is made through a formal asymptotic analysis. In both cases, we show that these limiting stress fields depend on the
geometry of the shell and on the boundary conditions.
(Accepted June 1, 1998) 相似文献
8.
Daniel M. Connor Robert M. Kriegel David M. Collard Charles L. Liotta David A. Schiraldi 《Journal of polymer science. Part A, Polymer chemistry》2000,38(8):1291-1301
Diacids of fused arenes have been prepared for use as covalently bound fluorescent optical brightening agents in condensation polymers. The monomers: dimethyl 1,6‐pyrene dicarboxylate, dimethyl 1,8‐pyrenedicarboxylate, dimethyl 2,7‐pyrenedicarboxylate, 1,8‐bis(2‐carboxybenzoyl)pyrene dimethyl ester, dimethyl 2,6‐anthracenedicarboxylate, dimethyl 2,7‐anthracenedicarboxylate and dimethyl 9,10‐anthracenedicarboxylate are copolymerized with poly(ethylene terephthalate) and their optical properties are assessed. All of the polymers give blue fluorescence, with the copolymer containing dimethyl 1,6‐pyrenedicarboxylate being the brightest. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 1291–1301, 2000 相似文献
9.
Spatially periodic patterning of the anchoring condition of a nematic liquid crystal (NLC) within a polymer matrix via a patterned photopolymerization affords a novel and facile method to prepare electrically switchable diffraction gratings. UV irradiation through a photomask of two comonomers, with opposite tendencies to align the NLC and also with different reactivity ratios, leads to definition of areas with either homeotropic or planar alignment of the NLC. Photopolymerization-induced diffusion of the monomers accounts for the spatial distribution of the concentration of these monomers. The resulting diffraction gratings are switchable under low electric fields and possess structural stability offered by the polymer matrix. 相似文献
10.
Jagtap SP Mukhopadhyay S Coropceanu V Brizius GL Brédas JL Collard DM 《Journal of the American Chemical Society》2012,134(16):7176-7185
In this work, a bicyclo[4.4.1]undecane scaffold is used to hold oligo(phenylene ethynylene) units in a cofacially stacked arrangement along the entire length of the conjugated units. We study the impact that the resulting strong interchain interactions have on the photophysical properties. The length of the individual oligomer branches was varied from three to five rings to investigate the effect of conjugation on the electronic properties of the stacked segments. Absorption and fluorescence spectra were recorded and compared to those of the corresponding unstacked analogues. Time-dependent density functional theory calculations were carried out and helped to rationalize the low-energy features present in the fluorescence spectra of the stacked systems. The calculations indicate that the low-energy emissions are due to the presence of excimer-like states. The stronger intensity of the low-energy fluorescence band observed in the five-ring stacked system compared to the three-ring analogue is attributed to the smaller activation barrier that separates the local intrachain state and the excimer-like state in the former compound. 相似文献