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221.
Z.Q. Ma W. Li D.M. Wang Z.X. Zhao Y. Wang W.J. Yang W.G. Zhao 《Solid State Communications》2006,137(8):413-416
Under an assumption of rectilinear trajectories for the projectile into a solid surface, a distinct expression for the ‘energy window’ of the driving atoms in a monolayer has been drawn for different ion-target systems, in which the atomic displacements take place primarily in the surface layer, while the subsurface layer is kept undamaged. This approach of determining the appropriate energy interval to enhance the mobility of adatom is applied to ion-assisted growth of zinc sulfide (ZnS), zinc selenide (ZnSe), and zinc telluride (ZnTe) epitaxial layers, respectively. The calculating results are in good agreement with the experimental observation of ZnTe semiconductor materials in the energetic cluster beam. 相似文献
222.
N.?Bhatia S.?S.?MalikEmail author A.?K.?Jain 《The European Physical Journal A - Hadrons and Nuclei》2005,26(2):241-251
The compound nucleus formation is considered as a two-step process of touching and subsequent tunneling of the projectile
into the target. The deep minima in the potential energy curve are due to shell effects in the experimental binding energies
and give possible target-projectile combinations for the synthesis of heavy and superheavy elements. The asymmetric channels
thus obtained are in remarkable agreement with the known experimental channels. In our model, the colliding partners are first
shown to be captured in the pocket behind the outer (touching) barrier and the composite system so formed finally tunnels
through the inner (fusion) barrier to form the resulting compound nucleus. These calculations reveal the importance of the
fusion barrier, which occur only for the asymmetric target-projectile combinations. The calculated fusion cross-sections show
a reasonable comparison with the observed one-neutron evaporation residue cross-sections. An estimate of the excitation energy
carried by the compound nucleus is also obtained from our model calculations. 相似文献
223.
C. Muri R.M. Anjos R. Cabezas P.R.S. Gomes S.B. Moraes A.M.M. Maciel G.M. Santos J. Lubian M.M. Sant'Anna C. Tenreiro R. Liguori Neto J.C. Acquadro P.A.B. Freitas 《The European Physical Journal A - Hadrons and Nuclei》1998,1(2):143-149
Elastic and inelastic scattering differential cross sections were measured in the energy range 30 MeV ≤ E
lab
≤ 55 MeV, for the 14N +59Co system. Ambiguities of the optical potential derived from the analysis of the elastic scattering data were removed by performing
calculations at the radius of sensitivity and by comparison with the available fusion cross section data. A simultaneous analysis
of the three mechanisms was performed by coupled channel calculations, and a unique energy independent nuclear potential was
found to be able to fit the data. Discussions and comparisons concerning the optical model, the threshold anomaly, full and
approximated coupled channel calculations are presented.
Received: 6 February 1997 / Revised version: 1 August 1997 相似文献
224.
H. Baba N. Takahashi A. Yokoyama T. Saito 《The European Physical Journal A - Hadrons and Nuclei》1998,3(3):281-292
The reaction of 238U with 12C was studied radiochemically with the purpose of elucidating fast fission characteristics. From the difference in the mass
distribution below and above the critical energy where fast fission is predicted to set in, fast fission component was extracted
in far-asymmetric mass region and interpreted as the mass diffusion following the Fokker-Planck equation. Anomalous charge
dispersion widths in the corresponding mass region and a sudden increase of the whole mass distribution width at the critical
energy were also observed to support the above result. The reaction time of fast fission deduced from the width and position
of the mass distribution was 5×10−21s as well by taking into account the effect of neutron emission during the diffusion process, which turned out to be more
than one order of magnitude longer than the corresponding life time of typical deep inelastic scattering but substantially
short compared to ordinary fusion-fission life time. Evaluation of the driving potential for mass drift required dinuclear
configuration be of an elongated or deformed form for fast fission in contrast to a more compact form for the deep-inelastic
process.
Received: 11 November 1997 相似文献
225.
The interaction potential for spherical-deformed reaction partners is calculated. The shape, separation and orientation dependence of the interaction potential and fusion cross section of the system ^32S+^154Sm are investigated within the double-folding model of the deformed nuclei. The effective nucleon-nucleon interaction is taken to be the M3Y-Reid potential. The density is considered for three terms of the expansion using the truncated multipole expansion method, which is a deformed Fermi shape With quadrupole and hexadecapole for the density distribution of ^154Sm. It is found for the interaction potential that the height and the position of barrier strongly depend on the deformations, the orientation angle of the deformed nucleus, and hence produce great effects on fusion cross section. The integrated fusion cross section is in good agreement with the experimental data. 相似文献
226.
In order to improve the photocatalytic activity, N-doped titanium oxide (TiO2) films were obtained by thermal oxidation of TiN films, which were prepared on Ti substrates by ion beam assisted deposition (IBAD). The dominating rutile TiO2 phase was found in films after thermal oxidation. According to the results of X-ray photoelectron spectroscopy (XPS), the residual N atoms occupied O-atom sites in TiO2 lattice to form TiON bonds. UV-vis spectra revealed the N-doped TiO2 film had a red shift of absorption edge. The maximum red shift was assigned to the sample annealed at 750 °C, with an onset wavelength at 600 nm. The onset wavelength corresponded to the photon energy of 2.05 eV, which was nearly 1.0 eV below the band gap of pure rutile TiO2. The effect of nitrogen was responsible for the enhancement of photoactivity of N-doped TiO2 films in the range of visible light. 相似文献
227.
R. Krücken S.J. Asztalos R.M. Clark M.A. Deleplanque R.M. Diamond P. Fallon I.Y. Lee A.O. Macchiavelli G.J. Schmid F.S. Stephens K. Vetter Jing-Ye Zhang 《The European Physical Journal A - Hadrons and Nuclei》2001,10(2):151-155
High-spin states in 112Pd were studied using prompt γ-ray spectroscopy with Gammasphere following heavy-ion-induced fission in the reaction 18O + 208Pb at 91 MeV. A new 8+ level at 2638 keV was discovered with transitions connecting it to the yrast band and the quasi-gamma band. The three, now
established, closely spaced 8+ states indicate a mixing between the ground-state band, s-band, and quasi-gamma band. Several high-spin structures with likely negative parity have been extended to higher spin and
it is proposed that they are based on the νh
11/2(g
7/2
d
5/2) and νh
11/2(s
1/2
d
3/2) configurations.
Received: 28 November 2000 / Accepted: 8 February 2001 相似文献
228.
H.A. Roth S.E. Arnell D. Foltescu Ö. Skeppstedt J. Blomqvist G. de Angelis D. Bazzacco S. Lunardi 《The European Physical Journal A - Hadrons and Nuclei》2001,10(3):275-287
High-spin level schemes of the N = 80 isotones 146Dy, 147Ho and 148Er have been investigated by in-beam γ-ray spectroscopic methods using the NORDBALL Compton-suppressed multidetector array
including proton and neutron selection. The projectile-target system 58Ni + 92Mo at 260 MeV beam energy has been used to produce the neutron-deficient N = 80 isotones. The previously known schemes have been extended to considerably higher spin and exitation energy, up to I = 23?, E
x≈ 8.9 MeV in 146Dy, I = 53/2?, E
x≈ 8.7 MeV in 147Ho and I = 23?, E
x≈ 9.6 MeV in 148Er. The results are discussed in terms of the spherical shell model. Many of the levels can be described within this framework.
Received: 12 January 2001 / Accepted: 11 April 2001 相似文献
229.
L.M. Pant R.K. Choudhury A. Saxena D.C. Biswas 《The European Physical Journal A - Hadrons and Nuclei》2001,11(1):47-58
Fission fragment mass and energy distributions and their correlations have been measured for the 16O and 19F + 209Bi reactions over a wide range of excitation energies ( E
* = 30-50 MeV). It is observed that in the case of 16O + 209Bi reaction, the average total fragment kinetic energy, <TKE> is nearly independent of the bombarding energy. However, in the case of 19F + 209Bi reaction, the average total kinetic energy of the fission fragments shows a peaking behaviour near the barrier. The variation
in <TKE> at near barrier energies in the 19F + 209Bi system seems to be correlated with corresponding strong variation in the variance of the fragment mass distribution. The
present results may imply certain dynamical effects leading to compact scission configurations in the fission of 19F + 209Bi system at near barrier bombarding energies.
Received: 9 April 2001 / Accepted: 26 May 2001 相似文献
230.
F. Soramel P. Bednarczyk M. Sferrazza D. Bazzacco D. De Acuñna G. de Angelis M. De Poli E. Farnea N.H. Medina R. Menegazzo L. Müller D.R. Napoli C.M. Petrache C. Rossi Alvarez F. Scarlassara G.F. Segato C. Signorini J. Styczeń G. Vedovato 《The European Physical Journal A - Hadrons and Nuclei》1999,4(1):17-19
The 178Pt and 181Au nuclei have been studied with the (230 MeV) 46Ti +142Nd fusion-evaporation reaction; γ-rays, evaporated particles and recoiling nuclei have been detected by the γ-array GASP +
the Si ball ISIS + the recoil mass spectrometer RMS. The newly observed structures in 178Pt and 181Au are most probably built on the proton and quasi-proton h9/2 and i13/2 configurations.
Received: 2 January 1998 / Revised version: 27 May 1998 相似文献