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31.
E. D'Anna S. Luby A. Luches E. Majkova M. Martino 《Applied Physics A: Materials Science & Processing》1993,56(5):429-436
Interdiffusion phenomena, thermal damage and ablation of W/Si and Si/W bilayers and multilayers under XeCl-excimer laser (=308 nm) irradiation at fluences of 0.15, 0.3 and 0.6 J/cm2 were studied. Samples were prepared by UHV e-beam evaporation onto oxidized Si. The thickness of W and Si layers and the total thickness of the structures were 1–20 nm and 40–100 nm, respectively. 1 to 300 laser pulses were directed to the same irradiation site. At 0.6 J/cm2 the samples were damaged even by a single laser pulse. At 0.3 J/cm2 WSi2 silicide formation, surface roughening and ablation were observed. The threshold for significant changes depends on the number of pulses: it was between 3–10 pulses and 10–30 pulses for bilayers with W and Si surfaces, respectively, and more than 100 pulses for multilayers with the same total thickness of tungsten. At 0.15 J/cm2 the periodicity of the multilayers was preserved. Temperature profiles in layered structures were obtained by numerical simulations. The observed differences of the resistance of various bilayers and multilayers against UV irradiation are discussed. 相似文献
32.
Daniel S. Covita Dimitrios F. Anagnostopoulos Hermann Fuhrmann Hubert Gorke Detlev Gotta Alexander Gruber Albert Hirtl Tomoichi Ishiwatari Paul Indelicato Thomas S. Jensen Eric-Olivier Le Bigot Valeri E. Markushin Michael Nekipelov Vladimir N. Pomerantsev Vladimir P. Popov Joaquim M. F. dos Santos Philipp Schmid Leopold M. Simons Marian Theisen Martino Trassinelli Joao F. C. A. Veloso Johann Zmeskal 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2018,72(4):72
33.
The energy per particle BA in nuclear matter is calculated up to high baryon density in the whole isospin asymmetry range from symmetric matter to pure neutron matter.The results,obtained in the framework of the Brueckner-Hartree-Fock approximation with two-and three-body forces,confirm the well-known parabolic dependence on the asymmetry parameterβ=(N?Z)/A(β^2 law)that is valid in a wide density range.To investigate the extent to which this behavior can be traced back to the properties of the underlying interaction,aside from the mean field approximation,the spin-isospin decomposition of BA is performed.Theoretical indications suggest that theβ^2 law could be violated at higher densities as a consequence of the three-body forces.This raises the problem that the symmetry energy,calculated according to theβ^2 law as a difference between BA in pure neutron matter and symmetric nuclear matter,cannot be applied to neutron stars.One should return to the proper definition of the nuclear symmetry energy as a response of the nuclear system to small isospin imbalance from the Z=N nuclei and pure neutron matter. 相似文献
34.
Martino Prizzi 《Journal of Differential Equations》2005,210(2):429-451
We study a non-autonomous parabolic equation with almost-periodic, rapidly oscillating principal part and nonlinear interactions. We associate to the equation a skew-product semiflow and, for a special class of nonlinearities, we define the Conley index of isolated compact invariant sets. As the frequency of the oscillations tends to infinity, we prove that every isolated compact invariant set of the averaged autonomous equation can be continued to an isolated compact invariant set of the skew-product semiflow associated to the non-autonomous equation. Finally, we illustrate some examples in which the Conley index can be explicitly computed and can be exploited to detect the existence of recurrent dynamics in the equation. 相似文献
35.
Allometry is crucial in biology; scaling relations are implied in laws of growth of living systems. The self similarity of Gompertzian growths of biological organisms plays a key role, in this regard, in biological similitude. The origin of allometric relationships and values of the scaling exponents is a source of debate, as well as the origin of the range of biological scales. But, besides biology, scaling and growth characterize many different complex systems. Encompassing these aspects in a unified view is an interesting target. In this paper we propose a coarse but significant model that is applied to astrophysical structures and biological organisms. The inclusion of such different systems suggests applications to fields where allometry is emerging, such as economics, urban planning and the social sciences. 相似文献
36.
Ali Maalaoui Vittorio Martino 《Calculus of Variations and Partial Differential Equations》2014,50(3-4):599-614
We consider a family of tight contact forms on the three-dimensional torus and we compute the relative Contact Homology by using the variational theory of critical points at infinity. We will also show local stability. 相似文献
37.
Marta Martino Andrea Salvadori Federico Lazzari Lorenzo Paoloni Surajit Nandi Giordano Mancini Vincenzo Barone Sergio Rampino 《Journal of computational chemistry》2020,41(13):1310-1323
The virtual-reality framework AVATAR (Advanced Virtual Approach to Topological Analysis of Reactivity) for the immersive exploration of potential-energy landscapes is presented. AVATAR is based on modern consumer-grade virtual-reality technology and builds on two key concepts: (a) the reduction of the dimensionality of the potential-energy surface to two process-tailored, physically meaningful generalized coordinates, and (b) the analogy between the evolution of a chemical process and a pathway through valleys (potential wells) and mountain passes (saddle points) of the associated potential energy landscape. Examples including the discovery of competitive reaction paths in simple A + BC collisional systems and the interconversion between conformers in ring-puckering motions of flexible rings highlight the innovation potential that augmented and virtual reality convey for teaching, training, and supporting research in chemistry. 相似文献
38.
Ciminiello P Dell'Aversano C Fattoruss E Forino M Magno S Poletti R 《Journal of chromatography. A》2002,968(1-2):61-69
A liquid chromatography mass spectrometry (LC-MS) method is proposed for the sensitive, specific and direct detection of yessotoxin and its analogues, marine biotoxins which are associated with diarrhetic shellfish poisoning (DSP) and which have been found in the North Adriatic sea since 1995. The LC-MS method provided a detection limit of 70 pg for yessotoxin in full scan mode and was applied to determine the toxic profiles of a number of extracts or partially purified fractions of toxic mussels collected along the Emilia Romagna coasts (Italy) in the period 1995-1999. Detection of a desulfo-yessotoxin derivative from Mytilus galloprovincialis collected in 1998 is also reported. 相似文献
39.
S. Colonna S. De Rossi M. Faticanti I. Pettiti P. Porta 《Journal of molecular catalysis. A, Chemical》2002,180(1-2):161-168
ZrO2-supported La, Co oxide catalysts with different La, Co loading (2, 6, 8, 12 and 16 wt.% as LaCoO3) were prepared by impregnation of tetragonal ZrO2 with equimolar amounts of La and Co citrate precursors and calcination at 1073 K. The catalysts were characterized by X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), and BET specific surface area determination. Catalytic CO oxidation was performed at 298–800 K. XRD revealed the presence of tetragonal zirconia with traces of the monoclinic phase. LaCoO3 perovskite was also detected for loading higher than 6%. XAS experiments suggested that at high loading LaCoO3 and Co3O4 were formed, while at low loading, La, Co oxide species interacting with support, and hard to be structurally defined, prevailed. The catalysis study evidenced that the catalytic activity was due to segregated and highly dispersed cobalt oxide species. 相似文献
40.
T. I. Mikhailova B. Erdemchimeg G. Kaminski A. G. Artyukh M. Colonna M. Di Toro I. N. Mikhailov Yu. M. Sereda H. H. Wolter 《Bulletin of the Russian Academy of Sciences: Physics》2009,73(6):852-857
The asymmetry of velocity distributions of projectile-like fragments produced in heavy ion collisions is considered. The calculations
performed in the transport model approach (Vlasov kinetic equation with the collision term) are compared with the experimental
data for the 22Ne (40MeV/nucleon) + 9Be and 18O (35 MeV/nucleon) + 9Be(181Ta) reactions. It is found that the velocity distributions contain two components: a direct component centered at the beam
velocity and a dissipative component at lower energies, leading to asymmetry of velocity distributions. The direct component
is interpreted empirically within the Goldhaber model, and the centroids and widths σ0 of the distributions for each fragment are extracted. It is found that value of σ0 derived from experimental data is smaller by a factor of 2 than the theoretical one. The dissipative (also called deep inelastic)
component is described well by the transport calculations. It is shown that the ratio of yields of direct and dissipative
components, which determines the asymmetry of velocity distributions, depends on shape of the deflection function.
Original Russian Text ? T.I. Mikhailova, B. Erdemchimeg, G. Kaminski, A.G. Artyukh, M. Colonna, M. Di Toro, I.N. Mikhailov,
Yu.M. Sereda, H.H. Wolter, 2009, published in Izvestiya Rossiiskoi Akademii Nauk. Seriya Fizicheskaya, 2009, Vol. 73, No.
6, pp. 898–903. 相似文献