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991.
E. Kolbe K. Langanke F.-K. Thielemann 《The European Physical Journal A - Hadrons and Nuclei》1998,3(4):389-396
We study the influence of a strange axial vector form factor Gs of the nucleon on the neutrino-induced proton and neutron knockout of 16O. In particular, we calculate how much Gs≠0 might affect the recently proposed signal for supernova νμ and ντ neutrinos in the Superkamiokande detector. We discuss whether Superkamiokande might be able to determine the value of Gs in a hypothetical neutrino-beam experiment. Finally we comment on the possible effect Gs≠0 might have on neutrino-nucleus cross sections in the neutrino-driven wind model for the nuclear r-process.
Received: 30 April 1998 / Revised version: 10 August 1998 相似文献
992.
B. Dubrulle F.-M. Bréon F. Graner A. Pocheau 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,4(1):89-94
We consider fields which take random values over several decades. Starting from physical examples, we postulate that scale is not an absolute quantity. We then establish the equivalence between two existing approaches based on scale symmetry arguments as general as possible.
This yields a classification of log-infinitely divisible laws, possibly universal. The physical significance of the parameters
entering in the classification is discussed.
Received: 7 November 1997 / Received in final form: 26 March 1998 / Accepted: 30 March 1998 相似文献
993.
A nonlinear model is developed for the photoresponse of a bolometric structure taking into account the temperature dependences
of the thermal constants of the YBaCuO/MgO structure and its boundary thermal resistance. The model also allows for the specific
form of the currentvoltage characteristic of YBaCuO and the heat release from the transport current flow. A comparison between
the experimental data and the model showed that the nonlinear thermal model accurately describes the temporal characteristics
of the photoresponse.
Fiz. Tverd. Tela (St. Petersburg) 40, 191–194 (February 1998) 相似文献
994.
S.F. Lienin R. Brüschweiler R.R. Ernst 《Journal of magnetic resonance (San Diego, Calif. : 1997)》1998,131(2):184-190
The viscosity-dependent retarding effect of a polymeric solvent on the rotation of small solute molecules is investigated by13C NMR relaxation measurements. It is found that the relaxation data of 1,3-dibromoadamantane in highly viscous polymeric chlorotrifluoroethene can be explained neither by isotropic nor by realistic anisotropic tumbling in a single environment. The experimental data are rationalized in terms of fast exchange between at least two environments with correlation times differing by up to two orders of magnitude. The study shows that a uniform retardation of molecular tumbling by a polymeric solvent, desirable for shifting the NMR observation window in studies of intramolecular mobility, is not always feasible. 相似文献
995.
F. Máca 《Czechoslovak Journal of Physics》1993,43(9-10):941-945
We present the calculations of electronic structure and photoemission spectra for a lattice-matched Ag-Au(111) superlattice. The selfconsistent band structure exhibits a superlattice gap at about 1 eV below the Fermi level. A surface state is found in this gap and its dispersion properties are investigated. Its energy location is varied with location of surface terminating plane within the superlattice period. The calculated normal photoemission spectra explain well available experimental data. 相似文献
996.
Summary A microwave coherent backscattering experiment has been carried out on Mirabelle, a weakly ionised plasma device, with the
objective of measuring the electron density fluctuation level. The experiment is a preliminary step in order to prepare the
detection system for a microwave stimulated backscattering experiment. The incident electromagnetic wave is focused in front
of a plane grid which excites ion acoustic or electron Bernstein waves inducing fluctuations in the plasma. The backscattering
signal is collected by the launching circuit and detected by homodyne mixing. The typical ratio of the scattered power to
the incident power is about 10−12 and the relative density fluctuations are of the order of δn
e/n
e=10−3 against a background electron density ofn
e=1–5·109 cm−3. The backscattering measurement is compared with Langmuir probe measurements. The spectral width of the backscattered signal
has also been studied, by taking into account effects due to the incident wave focusing and plasma wave damping.
The authors of this paper have agreed to not receive the proofs for correction 相似文献
997.
We summarize some recent results related to fluctuation-induced kinetics of diffusion-controlled processes. We show that kinetic behavior can be drastically changed due to fluctuation effects, spatial correlations between particles, and anomalous transport properties. In addition, we show that correlation-induced kinetics in some systems can govern the temporal evolution over the entire time domain. 相似文献
998.
José Natário 《General Relativity and Gravitation》2006,38(3):475-484
We find a class of warp drive spacetimes possessing Newtonian limits, which we then determine. The same method is used to
compute Newtonian limits of the Schwarzschild solution and spatially flat Friedmann-Robertson-Walker cosmological models.
This work was partially supported by FCT/POCTI/FEDER. 相似文献
999.
F. Selleri 《Foundations of Physics》2006,36(3):443-463
The experimental evidence for electromagnetic signals propagating with superluminal group velocity is recalled. Transformations of space and time depending on a synchronization parameter, e1, indicate the existence of a privileged inertial system. The Lorentz transformations are obtained for a particular e1≠0. No standard experiment on relativity depends on e1, but if accelerations are considered only e1=0 remains possible. The causal paradox generated by superluminal signals (SLS) in the theory of relativity does not exist in the theory with e1=0. The irrelevance of SLS for the Einstein, Podolsky and Rosen paradox is pointed out. 相似文献
1000.
We investigate multiphoton states generated by high-gain optical parametric amplification of a single injected photon—polarization encoded as a qubit. The experimental configuration exploits the optimal phase-covariant cloning. The output state of the apparatus is found to exhibit the quantum superposition property of mesoscopic multiphoton assemblies involving about 300 photons. This work represents an experimental advance toward the test of several fundamental quantum processes in mesoscopic or macroscopic frameworks. 相似文献