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991.
J. Suhonen J. Toivanen A. S. Barabash I. A. Vanushin V. I. Umatov R. Gurriarán F. Hubert Ph. Hubert 《Zeitschrift für Physik A Hadrons and Nuclei》1997,358(3):297-301
We apply the self-consistent renormalized proton-neutron QRPA (RQRPA) method to calculate the two-neutrino double beta (2νββ) decay matrix elements associated with the ground-state and excited-state transitions of the 82Se → 82Kr decay. The RQRPA method is an extension of the pnQRPA method and promotes the Pauli exclusion principle violated by the pnQRPA ground state and yields more stable nuclear matrix elements with increasing strength of the proton-neutron interaction. In the present work the RQRPA wave functions are also used to evaluate 2νββ-decay rates to excited final states. The resulting theoretical half lives are compared with the new stringent experimental limits obtained by using a HPGe detector and external sources of enriched selenium. 相似文献
992.
In this presentation, a review is given on the main effects of mineral particulate fillers (with an aspect ratio of about
unity) on the deformation and fracture of amorphous and semicrystalline thermoplastic and thermosetting polymers. Elastomeric
modifiers, polymer blends, and filled elastomers are not considered here. Fillers are generally used to reduce cost as well
as the thermal sensitivity of mechanical properties of the matrix material and to improve, if possible, the strength and toughness.
The addition of particulate fillers influences all stages of the fabrication and use of the resulting composites. We focus
on the effects of a stiff second phase on elastic moduli, matrix structure, and on deformation, creep, and failure mechanisms.
As the main mechanisms, particle-matrix debonding, void formation, and matrix microshear yielding are identified. Toughness
is less sensitive to the quality of adhesion since particle-matrix debonding and formation of voids can be tolerated. If well
controlled, debonding contributes to deformation (formation of voids should be well distributed in space and time). Reference
is also made to the surprising and positive effect of CaCO3 particles on the toughness and impact resistance of HDPE, which increases at small interparticle distances due to interfacial
effects on lamellar growth in the ligament area.
Submitted to the 11th International Conference on Mechanics of Composite Materials (Riga, June 11–15, 2000).
Published in Mekhanika Kompozitnykh Materialov, Vol. 36, No. 3, pp. 305–316, March–April, 2000. 相似文献
993.
994.
D. Ph. Sikovsky 《Thermophysics and Aeromechanics》2011,18(2):235-254
On the basis of the previously developed asymptotic theory of turbulent particle-laden flow with particle deposition in channels
coupled with the transport model for the particle Reynolds stress, an asymptotic solution to the problem on the deposition
of particles in the limit of high Reynolds numbers was obtained. The numerical calculations confirmed the presence, in the
region of the transition from the diffusion-impaction regime of particle sedimentation to the inertia-moderated regime, bifurcation
phenomenon of a solution found previously in earlier studies. Features of particle accumulation in the viscous sublayer are
analyzed. On the basis of the numerical solution, correlations for particle deposition velocity were obtained. Boundary conditions
of the wall-function type for particle concentration whose use allows widening the applicability limits of the equilibrium
Eulerian models in terms of particle inertia are proposed. 相似文献
995.
996.
The conductivity and thermal stability of H+(H2O)n β″ and ion rich β alumina single crystals have been measured by the complex impedance method in the 25–700°C temperature range. Two mechanisms of conductivity were assumed: proton transfer at lower temperatures and H3O+ diffusion in the high-temperature range. Both structures have similar properties, but ion rich β alumina possesses the best stability and the lowest activation energy (β: 0.15 eV, β″: 0.20 eV below 400 and 300°C respectively). The room-temperature conductivity is ≈5×10?6 Ω?1 cm?1. The conducting properties and mechanisms are discussed and compared to other protonic or ionic conductors. 相似文献
997.
Ph. Roche 《Communications in Mathematical Physics》1990,127(2):395-424
We show that cell calculus (first introduced by Ocneanu in the context of relative position of factors) is a technique which permits us to connect different integrable models. It generalizes the Vertex-IRF correspondence. 相似文献
998.
Grillon G Balcou P Chambaret J Hulin D Martino J Moustaizis S Notebaert L Pittman M Pussieux T Rousse A Rousseau J Sebban S Sublemontier O Schmidt M 《Physical review letters》2002,89(6):065005
Following the interaction of superintense, short pulse lasers and plasmas, ions can be accelerated to velocities sufficient to drive nuclear fusion reactions, in particular, by the process of Coulomb explosion of clusters [T. Ditmire, Nature (London) 398, 491 (1999)]]. We show here how short bursts of neutrons can be produced using a jet of low-density deuterated methane clusters. Ion velocity distributions were simultaneously measured by a Thomson parabola mass spectrometer, demonstrating deuteron energies up to 120 keV. We show that, in such conditions, nuclear fusion will occur not only in the hot plasma core, but also in the cold outer region by collision processes. 相似文献
999.
Using a unified macroscopic QED formalism, an integral equation for the van der Waals energy of a two-level atomic system near a carbon nanotube is derived. The equation is valid for both strong and weak atom-vacuum field coupling. By solving it numerically, the inapplicability of weak coupling-based van der Waals interaction models in the close vicinity of the nanotube surface is demonstrated. It is also shown that encapsulation of doped atoms into the nanotube is energetically more favorable than their outside adsorption by the nanotube surface. 相似文献
1000.
Yu. A. Fridman Ph. N. Klevets D.A. Matunin O.V. Kozhemyako 《Journal of Physics and Chemistry of Solids》2006,67(12):2458-2467
The phase states of a two-dimensional ferromagnet system with anisotropic exchange interaction have been investigated for various relations between the material constants. It is shown that the competition between the exchange and the one-ion anisotropies, and the account of the magnetodipolar and the magnetoelastic interactions lead to the sequence of the phase transitions. The explicit solutions of the dispersion equation have been found in the homogeneous phase states. 相似文献