排序方式: 共有230条查询结果,搜索用时 234 毫秒
31.
P.D. Shidling N. Madhavan V.S. Ramamurthy S. Nath N.M. Badiger Santanu Pal A.K. Sinha A. Jhingan S. Muralithar P. Sugathan S. Kailas B.R. Behera R. Singh K.M. Varier M.C. Radhakrishna 《Physics letters. [Part B]》2008
Evaporation residue (ER) cross sections and gamma multiplicity distributions have been measured for 16O + 184W and 19F + 181Ta systems in the excitation energy range of 50–90 MeV, leading to the same compound nucleus 200Pb∗. Comparison of experimental results of both the systems shows that ER cross sections and moments of gamma multiplicity distribution of 16O + 184W system are significantly higher than those of 19F + 181Ta system at higher excitation energies. Present measurements directly shows the experimental signature of entrance channel effect even with the systems which are not very different with respect to their entrance channel mass asymmetry. It is further demonstrated that the reduction in the ER cross section and moments of spin distribution for 19F + 181Ta system is mainly due to the suppression of fusion of higher l values. 相似文献
32.
Fu-Li Liu 《Physics letters. A》2008,372(39):6041-6046
Newton-Hooke group is the nonrelativistic limit of de Sitter (anti-de Sitter) group, which can be enlarged with transformations that describe constant acceleration. We consider a higher order Lagrangian that is quasi-invariant under the acceleration-extended Newton-Hooke symmetry, and obtain the Schrödinger equation quantizing the Hamiltonian corresponding to its first order form. We show that the Schrödinger equation is invariant under the acceleration-extended Newton-Hooke transformations. We also discuss briefly the exotic conformal Newton-Hooke symmetry in 2+1 dimensions. 相似文献
33.
Manley-Rowe relations are formulated for a discrete Hamiltonian system with an arbitrary number of resonances. Assuming that the resonances are defined as , where is an n×n integer matrix of rank r<n, and |ω〉≡T(ω1,…,ωn) is the frequency vector, the projection of the action vector |J〉 on is an adiabatic invariant. Hence n−r independent integrals, from where the conventional Manley-Rowe relations for a single resonance follow as a particular case. 相似文献
34.
This paper proposes a three-dimensional system for modelling stress in thin films deposited on plane substrates much thicker than the film itself. The approach is the minimization of the deformation energy of the sample (substrate + film), considering the deformed substrate as a small spherical surface with large curvature radius. Results of the model show the validity limits of the well-established Stoney equation that satisfy the upper theoretical limit of Poisson ratio (ν) for isotropic materials. Our main result is that the stress values obtained in general literature using Stoney equation are underestimated when considering a typical Poisson ratio for substrates in the range of 0.25 ≤ νs ≤ 0.4. 相似文献
35.
The pulsed intense ion beam, emitted from a dense plasma focus (DPF) discharges performed with hydrogen gas, has been used to ablate the graphite target depositing diamond-like carbon (DLC) films on Si substrates. The substrates were mounted on a holder, which allowed for deposition at positions between normal and 20° off-normal to the target. The samples were removed for analysis after 10 and 20 shots. Nano-particles were observed in the films by a field-emission scanning electron microscope. Raman spectra indicate that sample deposited at 20° off-normal with 20 shots possesses the highest sp3 content among the samples. The film deposited at this position was also found has the highest hardness. 相似文献
36.
In the present work we have grown twin-free single crystal metal films of iridium (Ir), rhodium (Rh), platinum (Pt) and ruthenium (Ru) on silicon (1 1 1) substrates via an yttria-stabilized zirconia (YSZ) buffer layer. A prerequisite for the realisation of heteroepitaxial metal films without additional texture components was the twin-free deposition of the YSZ films by pulsed laser deposition (PLD). For the metal films on top, a novel two-step growth process was applied with an extremely low deposition rate for the first 20 nm. For all metals, a drastic texture improvement by up to a factor of 9 could be observed compared to the oxide buffer layer. Minimum values were 0.18° (Ir) and 0.12° (Rh) for tilt and twist, respectively. For all four metals investigated, twin-free epitaxial films could be grown on YSZ/Si(1 1 1) whereas the twinning problem for platinum films was solved by decoupling the Pt-YSZ interface via an additional iridium interlayer. The grown metal/YSZ/Si(1 1 1) multilayer samples offer the possibility to integrate a variety of interesting nanostructures and functional materials on silicon. They are now available in 4 in wafer size. 相似文献
37.
A. Minguzzi G. Ferrari Y. Castin 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2001,17(1):49-55
We describe the excitation spectrum of a two-component neutral Fermi gas with attractive interactions in the superfluid phase
at finite temperature by deriving a suitable Random-Phase approximation in the collisionless regime with the technique of
functional derivatives. The obtained spectrum for the homogeneous gas at small wavevectors contains the Bogoliubov-Anderson
phonon and is essentially different from the spectrum predicted by the static Bogoliubov theory, which instead shows an unphysically
large response. We adapt the results for the homogeneous system to obtain the dynamic structure factor of a harmonically confined
superfluid and we identify in the spectrum a unique feature of the superfluid phase.
Received 28 March 2001 相似文献
38.
S. Mukherjee A. Sharma S. Sodaye B.S. Tomar A. Goswami S.B. Manohar 《The European Physical Journal A - Hadrons and Nuclei》2001,12(2):199-205
Incomplete fusion reactions were investigated by measuring the excitation functions of nine evaporation residues in 16O + 51V reaction in the beam energy 4-6 MeV/amu, using the well-known recoil catcher technique and gamma-ray spectrometry. The experimental
data were compared with that obtained from Monte Carlo simulation calculations using the PACE2 code. The results indicate
the presence of incomplete fusion process in the production of two alpha emission products. This was further confirmed by
the measurement of recoil range distribution of these isotopes at 96 MeV beam energy. Calculations of the average angular
momentum associated with these products revealed the peripheral nature of these ICF reactions.
Received: 20 June 2001 / Accepted: 11 September 2001 相似文献
39.
Y.X. Watanabe A. Yoshida T. Fukuda T. Sekine Y. Watanabe H. Ikezoe Y. Nagame T. Ikuta I. Nishinaka Y. Mizoi J. Nakano M. Hirai H. Sakurai H. Kobinata Y. Pu K. Kimura M. Ishihara 《The European Physical Journal A - Hadrons and Nuclei》2001,10(4):373-379
A systematic study of the sub-barrier fusion reactions with neutron-rich projectiles has been carried out for three isotopes
27,29,31Al bombarding a 197Au target. A target chamber equipped with a target stack and sets of MWPC was employed in order to enhance the efficiency
of the radioactive beam experiment. Coupled-channel calculations including the quadrupole excitations do not well fit the
measured fusion excitation functions, whereas flat barrier distributions to represent the coupling to the neutron transfer
largely account for the observed enhancement of the sub-barrier fusion cross-sections.
Received: 13 March 2001 / Accepted: 27 April 2001 相似文献
40.