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991.
Gomez L Slutzky C Ferron J de La Figuera J Camarero J Vazquez De Parga AL de Miguel JJ Miranda R 《Physical review letters》2000,84(19):4397-4400
Generic computer simulations using empiric interatomic potentials suggest a new, collective mechanism that could be responsible for mixing at heteroepitaxial interfaces. Even if single adsorbate atoms diffuse by hopping on the substrate surface and do not mix at the terraces, two-dimensional islands formed by nucleation may become unstable above a certain critical size and explode upwards forming clusters of several atomic layers. This process is accompanied by strong distortions of the underlying atomic layers, and on soft materials it can result in surface etching and incorporation of substrate atoms into the islands. 相似文献
992.
Buatier De Mongeot F Costantini G Boragno C Valbusa U 《Physical review letters》2000,84(11):2445-2448
We have investigated the homoepitaxial growth of Ag(110) in the multilayer regime. After deposition of 30 monolayers of Ag at a temperature of 210 K a ripplelike surface instability is produced and the ridges of the ripples, as well as the majority steps, are found to be parallel to <11;0> which is the thermodynamically favored orientation. As the deposition temperature is decreased to 130 K, an unexpected 90 degrees switch of the ripple orientation is observed. The ridges of the ripples and the steps are in this case parallel to <100>. In the intermediate temperature range a checkerboard of rectangular mounds results. We interpret our results in terms of the peculiar hierarchy of interlayer and intralayer diffusion barriers present on the anisotropic Ag(110) surface. 相似文献
993.
Kylstra NJ Worthington RA Patel A Knight PL Vazquez De Aldana JR Roso L 《Physical review letters》2000,85(9):1835-1838
An analysis of the influence of the magnetic field of an intense, high-frequency laser pulse on the stabilization of an atomic system is presented. We demonstrate that at relatively modest intensities the magnetic field can significantly alter the dynamics of the system. In particular, a breakdown of stabilization occurs, thereby restricting the intensity regime in which the atom is relatively stable against ionization. Counterpropagating pulses do not negate the detrimental effects of the magnetic field. We compare our quantum mechanical results with classical Monte Carlo simulations. 相似文献
994.
995.
D. Antonucci D. de Ceglia A. D’Orazio M. De Sario V. Marrocco V. Petruzzelli F. Prudenzano 《Optical and Quantum Electronics》2007,39(4-6):353-360
In this paper we discuss the conditions to obtain the enhancement of second harmonic generation in a two-dimensional circular
photonic crystal AlGaAs cavity. The photonic crystal circular cavity offers the possibility of having high-Q resonance modes
with respect to those obtained with other types of photonic crystal lattices. The crystallographic cut of the AlGaAs provides
a strong nonlinear coupling between a transverse-magnetic (TM) polarized resonant mode at the fundamental wavelength and a
transverse-electric (TE) polarized resonant mode at second harmonic wavelength. The double resonance condition leads to a
strong improvement of the second harmonic generation process. A preliminary linear analysis has been performed by using the
finite-difference time-domain method, which includes the dispersive response of the material, modeled using the well-known
one-pole pair Lorentzian function. 相似文献
996.
Beniamino Cappelletti Montano Antonio De Nicola 《Journal of Geometry and Physics》2007,57(12):2509-2520
We present a compared analysis of some properties of 3-Sasakian and 3-cosymplectic manifolds. We construct a canonical connection on an almost 3-contact metric manifold which generalises the Tanaka–Webster connection of a contact metric manifold and we use this connection to show that a 3-Sasakian manifold does not admit any Darboux-like coordinate system. Moreover, we prove that any 3-cosymplectic manifold is Ricci-flat and admits a Darboux coordinate system if and only if it is flat. 相似文献
997.
C. M. Cattadori M. De Deo M. Laubenstein L. Pandola V. I. Tretyak 《Physics of Atomic Nuclei》2007,70(1):127-132
Recent observation of β decay of 115In to the first excited level of 115Sn with an extremely low Q
β value (Q
β ≤ O(1) [keV]) could be used to set a limit on neutrino mass. To give a restriction potentially competitive with those extracted
from experiments with 3H (≃2 eV) and 187Re (≃15 eV), the atomic mass difference between 115In and 115Sn and energy of the first 115Sn level should be remeasured with higher accuracy (possibly of the order of ∼1 eV).
The text was submitted by the authors in English. 相似文献
998.
F. Ambrosino F. Anulli D. Babusci S. Bianco C. Bini N. Brambilla R. De Sangro P. Gauzzi P.M. Gensini S. Giovannella V. Muccifora M. Negrini F. Nguyen S. Pacetti G. Pancheri M. Passera A. Passeri A.D. Polosa M. Radici Y.N. Srivastava A. Vairo G. Venanzoni G. Violini 《The European Physical Journal C - Particles and Fields》2007,50(3):729-768
We present a detailed study, done in the framework of the INFN 2006 Roadmap, of the prospects for e+e- physics at the Frascati National Laboratories. The physics case for an e+e- collider running at high luminosity at the φ resonance energy and also reaching a maximum center of mass energy of 2.5 GeV
is discussed, together with the specific aspects of a very high luminosity τ-charm factory. Subjects connected to kaon decay
physics are not discussed here, being part of another INFN Roadmap working group. The significance of the project and the
impact on INFN are also discussed. All the documentation related to the activities of the working group can be found in http://www.roma1.infn.it/people/bini/roadmap.html. 相似文献
999.
G. Benzoni F. Azaiez S. Leoni S. Battacharyya R. Borcea A. Bracco L. Corradi D. Curien G. De France Zs. Dombrádi E. Fioretto S. Franchoo S. Grevy F. Ibrahim S. Iulian G. Mukherjee A. Navin G. Pollarolo N. Redon P. H. Regan M. Rejmund C. Schmitt G. Sletten D. Sohler M. Stanoiu S. Szilner D. Verney 《The European physical journal. Special topics》2007,150(1):83-86
A study of deep-inelastic and multi-nucleon transfer reactions to populate neutron-rich
O, Ne and F nuclei is here presented. The reaction under analysis employed a beam of radioactive
24Ne at 7.9 AMeV, provided by the
SPIRAL facility at Ganil, impingin on a 208Pb target. The reaction products have been
detected in the VAMOS spectrometer in coincidence with gamma rays
measured by the EXOGAM array. Preliminary results here presented show a selectivity
in the population of states of different nature. 相似文献
1000.
The dynamics of a titanium plasma species, induced in air by coupling a fs-ablating laser pulse with an orthogonal ns-reheating laser source placed at the fixed distance of 1.0 mm from the target surface, has been followed by temporally resolved emission spectroscopy. The temporal evolutions of plasma features such as excitation temperatures and electron densities have been evaluated by using two different laser energies of the first fs-ablating laser pulse (0.8 mJ and 3.0 mJ). Optimum inter-pulse delay times, experimentally determined, of 250 μs and 500 μs were used for the fs laser energy of 3.0 mJ and 0.8 mJ, respectively. By experimental inspections of the main plasma species electronic transitions so obtained, a strong enhancement was evaluated up to one and two orders of magnitude for Ti(I) and Ti(II), respectively. Independently from the fs laser energy employed, the plasma features showed the same temporal behaviour implying that the ns-reheating characteristics of this process belong to the reheating mechanism itself. The experimental results have been discussed and the excited species evolutions and elementary processes involved, as well as, the local thermodynamic equilibrium departures, have been outlined. 相似文献