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21.
Rajesh Kharab Pardeep Singh Ravinder Kumar 《中国物理快报》2007,24(3):656-659
We investigate the effects of higher order multipole transitions, in particular electric quadrupole (E2) and El-E2 interference, on the Coulomb dissociation of 19 C within the framework of the first order eikonal approximation. The sensitivity of the total Coulomb breakup cross section and the longitudinal momentum distribution of the core fragment to these effects are checked. The breakup occurs predominately through the dipole transition and the contribution of E2 transition to the total cross section is found to be within the range from 1 to 3% of that of El. It is further observed that the El-E2 interference term contributes nothing to the integrated cross section. On the other hand, the longitudinal momentum distribution is observed to be insensitive to the E2 transition while the El-E2 interference introduces a small asymmetry in its shape. 相似文献
22.
H^+注入锗酸铋(Bi4Ge3O12或BGO)晶体引起某些效应,如辐射损伤,光学吸收和近表层区域的晶体分解。经H^+注入后,BGO晶体的颜色变成棕色,但实验中证实不了该变化是由色心的产生所引起。此外,实验中也示观察到H^+注入BGO晶体中有离子束诱发的光学活性变化。可见在注入过程中,未发生从Bi4Ge3O12转变到Bi12GeO20的结构相变,由此预见,注入过程中可能发生离子束引起的晶体分解。H^ 相似文献
23.
M. Karny L. Batist B. A. Brown D. Cano-Ott R. Collatz A. Gadea R. Grzywacz A. Guglielmetti M. Hellstrm Z. Hu Z. Janas R. Kirchner F. Moroz A. Piechaczek A. P
ochocki E. Roeckl B. Rubio K. Rykaczewski M. Shibata J. Szerypo J. L. Tain V. Wittmann A. Whr 《Nuclear Physics A》2001,690(4):45
The Gamow–Teller β decays of the neutron-deficient indium isotopes 104–107In have been investigated by using total absorption γ-ray spectrometry on mass-separated sources. The experimental Gamow–Teller strength, deduced as a function of the excitation energy in the daughter nuclei 104–107Cd, is compared to shell-model predictions. 相似文献
24.
A. Karnik S. Kailas A. Chatterjee P. Singh A. Navin D. C. Biswas D. M. Nadkarni A. Shrivastava S. S. Kapoor 《Zeitschrift für Physik A Hadrons and Nuclei》1995,351(2):195-198
The fission fragment angular distributions for the system12C +232Th have been measured in the energy range 0.97<>c.m./VB<1.22. the=" measured=" anisotropies=" have=" been=" compared=" with=" the=" predictions=" of=" the=" standard=" saddle=" point=" statistical=" model,=" using=" the=" second=" moment=" of=" the=" compound=" nucleus=" spin=" distribution=">1.22.>l2 deduced from a Wong model fit to the fission excitation function. While the measured anisotropies agree with the standard saddle point statistical model for Ec.m./VB>1.05, they are abnormally large at lower energies. This is also true for the existing measurements of16O and19F +232Th systems. Since for this system pre-equilibrium fission contributions are not expected, this anomaly indicates strong channel coupling effects leading to an increase in l2 at sub-barrier energies.The authors thank Drs. R.K. Choudhury and A. Saxena for useful discussions, Dr. R.J. Singh for making the thorium target and the Pellectron operation staff for excellent operation of the machine. 相似文献
25.
A.V. Pan P. Esquinazi 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,17(3):405-410
We have investigated the influence of a driving force on the elastic coupling (Labusch parameter) of the field-cooled state
of the flux line lattice (FLL) in 400 nm thick YBa2Cu3O7 superconducting films. We found that the FLL of a field-cooled state without driving forces is not in an equilibrium state.
Results obtained for magnetic fields applied at and 30 relative to CuO2 planes, show an enhancement of the elastic coupling of the films at driving current densities several orders of magnitude
smaller than the critical one. Our results indicate that the FLL appears to be in a relatively ordered, metastable state after
field cooling without driving forces.
Received 21 December 1999 相似文献
26.
A. Chakraborti B.K. Chakrabarti 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,17(1):167-170
We consider a simple model of a closed economic system where the total money is conserved and the number of economic agents
is fixed. Analogous to statistical systems in equilibrium, money and the average money per economic agent are equivalent to
energy and temperature, respectively. We investigate the effect of the saving propensity of the agents on the stationary or
equilibrium probability distribution of money. When the agents do not save, the equilibrium money distribution becomes the
usual Gibb's distribution, characteristic of non-interacting agents. However with saving, even for individual self-interest,
the dynamics becomes cooperative and the resulting asymmetric Gaussian-like stationary distribution acquires global ordering
properties. Intriguing singularities are observed in the stationary money distribution in the market, as functions of the
marginal saving propensity of the agents.
Received 2 May 2000 相似文献
27.
V. Hardy S. Hébert J. Provost Ch. Simon 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,16(1):107-111
To investigate the existence of a splay effect in Bi2Sr2CaCu2O8 (Bi-2212), vortex pinning has been studied in different configurations of strongly inclined columnar defects (75 from the c axis), installed by heavy-ion irradiation. It is shown that the symmetry of the track setting with respect to the field direction
is a more influent parameter than the presence of a dispersion in the track directions. We claim that the enhanced pinning
efficiency which is observed in some splayed configurations of columnar defects in Bi-2212 can be interpreted without invoking
a splay effect.
Received 27 December 1999 相似文献
28.
We have analyzed the optical properties of a-Ge30-xSbxS70 chalcogenide glass films (x=0,10,20 and 30 at%); the chalcogenide films were prepared by vacuum thermal evaporation. The optical-absorption data indicate that the absorption mechanism is non-direct transition. We found that the optical band gap, Eopt, decreases from 2.04±0.01 to 1.74±0.01 eV, whereas the refractive index increases with increasing Sb content. Data are analyzed by the Wemple equation, which is based on the single-oscillator model. 相似文献
29.
F. F. Gong F. X. Gong F. Y. Gong 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,49(3):267-268
Open dynamic behaviour of financial markets with internal
interactions between agents and with external “fields” from other systems
are investigated using the approach of Grossman and Stiglitz for inefficient
markets, and Keynes for interference of the market using physics of finance
(referred to hereafter as phynance). The simulation results indicate that
the NYSE data analyzed in Plerou, V. et al., Nature 421, 130 (2003) can be fitted
by an equation of order parameter Φ and local deviation R of type:
-(R+0.03) Φ+ 0.6 Φ3 + 0.02 = 0, which is shown to be in
remarkable agreement with Plerou's data. 相似文献
30.
By means of cluster models coupled with density functional theory, we have studied the hydroboration of the Ge(1 0 0)-2 × 1 surface with BH3. It was found that the Ge(1 0 0) surface exhibits rather different surface reactivity toward the dissociative adsorption of BH3 compared to the C(1 0 0) and Si(1 0 0) surfaces. The strong interaction still exists between the as-formed BH2 and H adspeices although the dissociative adsorption of BH3 on the Ge(1 0 0) surface occurs readily, which is in distinct contrast to that on the C(1 0 0) and Si(1 0 0) surfaces. This can be understood by the electrophilic nature of the down Ge atom, which makes it unfavourable to form a GeH bond with the dissociating proton-like hydrogen. Alternatively, it can be attributed to the weak proton affinity of the Ge(1 0 0) surface. Nevertheless, the overall dissociative adsorption of BH3 on group IV semiconductor surfaces is favourable both thermodynamically and kinetically, suggesting the interesting analogy and similar diversity chemistry of solid surface in the same group. 相似文献