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141.
142.
143.
C. Fort A. Bambini L. Cacciapuoti F.S. Cataliotti M. Prevedelli G.M. Tino M. Inguscio 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,3(2):113-118
We report on a theoretical and experimental investigation of 39K magneto-optical trapping. The small hyperfine splitting characterizing the upper level of the cooling transition affects
the cooling mechanism. In order to model the atom-laser interaction, the whole level structure of the D2 line has to be taken into account. Two different regimes have been recognized, one optimizing the loading of the trap, the
second minimizing the temperature of the atoms. We investigated these two regimes experimentally and found results in agreement
with the theoretical predictions.
Received: 6 March 1998 / Received in final form: 13 May 1998 / Accepted: 13 May 1998 相似文献
144.
I. Josopait L. Dobrek L. Santos A. Sanpera M. Lewenstein 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,22(3):385-391
The atom optics of Bose-Einstein condensates containing a vortex of circulation one is discussed. We first analyze in detail
the reflection of such a condensate falling on an atomic mirror. In a second part, we consider a rotating condensate in the
case of attractive interactions. We show that for sufficiently large nonlinearity the rotational symmetry of the rotating
condensate is broken.
Received 16 September 2002 / Received in final form 17 November 2002 Published online 11 February 2003 相似文献
145.
N. Betz A. Le Moël E. Balanzat J. M. Ramillon J. Lamotte J. P. Gallas G. Jaskierowicz 《Journal of Polymer Science.Polymer Physics》1994,32(8):1493-1502
Poly(vinylidene difluoride) (PVDF) films were irradiated by means of heavy ions (in the electronic stopping-power range) and electrons. Both types of ionizing radiation induce in the polymer film ionizations and excitations, but swift heavy ions induce a huge density of excitations and ionizations along the ion path. Dose-range goes from 0.3 to 40 MGy. Irradiations were performed with Kr ions in the presence of helium, hydrogen, deuterium, and oxygen. Fourier transform infrared (FTIR) transmission measurements show differences in the nature of the created defects. Triple bonds are characteristic of the Kr ion irradiation. Double bonds, isolated and conjugated, exist for both kinds of radiation, but concentrations are higher with the Kr radiation. The presence of oxygen during irradiation produces oxidization defects. Typical bands of hydroxyls and carbonyls can be seen, respectively, in the 3800-3000 cm?1 zone and ca. 1850–1730 cm?1. The formation of conjugated double bonds is enhanced when the Kr irradiation is performed under an O2 atmosphere. © 1994 John Wiley & Sons, Inc. 相似文献
146.
Ashcroft’s analytic bare ion pseudopotential form factor with a modified Hartree dielectric function has been employed to
represent the temperature dependent interionic potential. This potential includes both direct ion-ion interaction and indirect
ion-electron-ion interaction with and without the effects of ‘d’ bands, in some scantily studied complexbcc metals vizbcc Ti, Zr and Hf. The ab initio radial and tangential force constants extending out to 15th nearest neighbours are computed
for the metals. The said potential is used for predicting the binding energy, elastic constants and phonon dispersion of the
above mentioned metals and the results are satisfactorily compared with the corresponding measured data. 相似文献
147.
强磁场下的固体物理研究进展 总被引:2,自引:0,他引:2
强磁场下的物理研究是一个富有成果的研究领域,40T以下稳态强磁场的研制成功为固体物理研究提供了新的科学机遇。文章简要地介绍强磁场下某些固体物理,其中包括高温超导体的H-T相图和非费米液体行为,德哈斯(de Haas)效应和费米面性质,电子的Wigner结晶及其动力学行为,磁场诱导的相变(如绝缘体-金属和超导转变),多级磁有序,串级自旋密度波和大块材料中的量子霍尔效应等的实验研究的近期进展,希望以此引起人们对国内强磁场下物理研究的关注。 相似文献
148.
S.M.S. da Costa M.H.F. Bettega 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1998,3(1):67-71
We report elastic integral, momentum transfer and differential cross sections for electron scattering by N2O for energies up to 50 eV. These results were obtained at the static-exchange approximation with the Schwinger Multichannel
Method with Pseudopotentials [M.H.F. Bettega, L.G. Ferreira and M.A.P. Lima, Phys. Rev. A 47, 1111 (1993)]. In general our results show good agreement with experimental data and with other theoretical results but some
discrepancies are found. We have also found a shape resonance around 4 eV in agreement with previous calculations using the R-matrix Method of Sarpal et al. [J. Phys. B 29, 857 (1996)]. On the other hand, the existence of a resonance at about 13 eV, clearly seen by the Schwinger Variational Iterative Method [Michelin et al., J. Phys. B 29, 2115 (1996)], can not be confirmed by our calculations. At this energy, our cross sections show a broad bump with no clear resonant behavior given by the eigenphase sum.
Received: 13 November 1997 / Revised: 13 March 1998 / Accepted: 9 April 1998 相似文献
149.
The differential cross-sections forē-helium elastic scattering are calculated by using Yateshigh-energy higher order Born approximations, through 0 (K
i
Emphasis>−2
) of the incident electron momentum, and comparisons have been made with the recent theoretical and experimental results. 相似文献
150.
K Narasimha Swamy 《Pramana》1975,4(4):175-183
The excess properties of mixing were calculated for seven systems Ar-CH4; Ar-N2; Ar-O2; Ar-CO; CO-CH4; O2-N2; N2-CO, using the Caranhan and Starling equation of state of rigid spheres and the Longuet-Higgins and Widom model. Two sets
of calculations were done one using the experimentalG
E
to calculateS
E
,H
E
andV
E
, and the other making use of Miller’s cross parameter values. The calculated values are compared with those of Snider and
Herrington and Miller’s values and also with the experimental values. The agreement was found to be good. 相似文献