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771.
Zhi Yong He Gen Ming Jin Zu Yu Li Li Min Duan Guang Xi Dai Bao Guo Zhang He Yu Wu Wan Xin Wen Yu Jin Qi Qing Zheng Luo Su Fang Wang 《The European Physical Journal A - Hadrons and Nuclei》1998,1(1):61-64
Emission orders of light charged particles and Li fragments from highly excited fissioning nuclei in the reaction of 40Ar+197Au at E
beam
/A=25 MeV have been studied by measuring difference velocity distributions of two correlated particles at small relative angles
in coincidence with two fission fragments. By comparing the data with three-body trajectory calculations, we found that high
velocity deuterons are emitted prior to high velocity Li fragments but low velocity deuterons are emitted after low velocity
Li fragments. On the other hand, no preferential emission was observed among light particles, such as protons and deuterons.
Furthermore, the emission orders are found to depend only weakly on the mass asymmetry of fission fragments.
Received: 3 June 1997 / Revised version: 23 July 1997 相似文献
772.
L. Lebreton D. Benchekroun E. Bisquer B. Chambon B. Cheynis A. Demeyer D. Doré D. Drain E. Gerlic D. C. P. Lautesse C. Pastor M. Stern L. Vagneron C. Vincent-Donnet A. Chabane A.J. Cole P. Désesquelles A. Giorni D. Heuer A. Lleres J.B. Viano 《The European Physical Journal A - Hadrons and Nuclei》1998,3(4):325-333
The formation and the deexcitation of the composite nucleus formed during the Ni + Al reaction at 28 A·MeV has been studied
with the 4 π multidetector AMPHORA. A rigourous selection of the experimental data is described in order to extract a central
collision sample. Then different models are compared to the data. The incomplete fusion process is in agreement with the data.
The azimuthal angle correlations of He-Li and Li-Li pairs have been used to discriminate sequential or instantaneous emission.
The sequential deexcitation is more consistent with all the data. The different analyses allow to describe all the characteristics
of the compound nucleus and finally a fusion cross section of 300 ± 100 mbarn has been measured.
Received: 11 February 1998 / Revised version: 1 August 1998 相似文献
773.
The emission of light charged particles in the fission process is of interest as they are believed to emerge from the neck
region of the deformed fissioning nucleus at a time close to the scission point and may thus prove a useful probe to investigate
the last stages of fission close to the rupture point. Experimental results on light charged particle emission and the efforts
made to obtain information about the scission point parameters therefrom are reviewed. 相似文献
774.
Chelluri C. A. Sastri 《Journal of statistical physics》1975,13(1):43-60
It is shown that macroscopic correlations in a fluid are conserved for macroscopically long times. The equations of conservation can be written in a form independent of the density of the fluid and are therefore valid for a liquid as well as for a gas. The possibility of developing a kinetic theory of turbulence on the basis of these equations (along the lines of V. N. Zhigulev and of S. Tsugé) is indicated.The contents of this paper formed part of the Ph.D. thesis submitted by the author under the supervision of Prof. Harold Grad to the Department of Mathematics, New York University and issued as NYU-Courant Institute of Mathematical Sciences Technical Report MF-72, October 1973. 相似文献
775.
Motion of a driven and heavily damped sine-Gordon chain with a low density of kinks and tight coupling between particles is controlled by the nucleation and subsequent annihilation of pairs of kinks and antikinks. We show that in the steady state there are no spatial correlations between kinks or between kinks and antikinks. For a given number of kinks and antikinks all geometrical distributions are equally alike, as in equilibrium. A master equation for the probability distribution for the number of kinks on a finite chain is solved, and substantiates the physical reasoning in previous work. The probability distribution characterizing the spread along the direction of particle motion of a finite chain in equilibrium as well as in the driven overdamped case is derived by simple combinatorial considerations. The spatial spread of a driven chain in the thermodynamic limit does not approach a steady state; a given particle followed in time deviates as t1/2 from its average forced motion. This result follows from the hydrodynamic equations for the dilute kink gas. Comparison is made with other recent results. 相似文献
776.
S. Chaturvedi C. W. Gardiner I. S. Matheson D. F. Walls 《Journal of statistical physics》1977,17(6):469-489
A stochastic analysis of the spatial and temporal structures in the Prigogine-Lefever-Nicolis model (the Brusselator) is presented. The analysis is carried out through a Langevin equation derived from a multivariate master equation using the Poisson representation method, which is used to calculate the spatial correlation functions and the fluctuation spectra in the Gaussian approximation. The case of an infinite three-dimensional system is considered in detail. The calculations for the spatial correlation functions and the fluctuation spectra for a finite system subject to different kinds of boundary conditions are also given. 相似文献
777.
2.1AGeVNe NaF碰撞中的粒子群关联与集体性 总被引:1,自引:0,他引:1
提出了粒子群关联概念,并以此建立了一种检测集合流的新方法,采用新方法对2.1AGeVNe+NaF碰撞的Bevalac流光室4π实验事件粒子群的关联进行了研究.通过与蒙特卡罗结果进行比较,推测该实验事件集合流的集体性约在75%-95%之间。 相似文献
778.
T. Grenet M.C. Cheynet 《The European Physical Journal B - Condensed Matter and Complex Systems》2000,13(4):701-705
We present the results of an electron energy loss spectroscopy (EELS) investigation of the icosahedral quasicrystals i-Al-Cu-Fe,
i-Al-Pd-Mn and i-Al-Pd-Re. The spectra of the three systems studied are very similar. Their main contribution comes from a
broad plasmon like peak, which can be interpreted as an “s-p" electron plasmon damped by “d" electron interband transitions. We show that it is similar to those found in other simple crystalline aluminum-transition
metal alloys, so that no specificity related to the quasicrystalline order of the alloys dominates.
Received 3 November 1998 and Received in final form 16 July 1999 相似文献
779.
Relativistic multichannel treatment of autoionization Rydberg series of 4s^2nf(n=4- 23)J^π -(7/2)° for scandium 下载免费PDF全文
Based on relativistic multichannel theory, this paper calculates the energy levels of autoionization Rydberg series 4s^2nf(n=4- 23)J^π -(7/2)° of scandium at different levels of approximation within the framework of multichannel quantum defect theory. The present results show that the dipole polarizations play an important role. Considering the dynamical dipole polarization effects, this paper finds that the difference between calculated and experimental quantum defects for the 4s^2nf(n=4- 23)J^π -(7/2)° series is generally about 0.01- 0.03. Furthermore, the reason that 4s^216f is obscured in experimental spectra is suggested to be the interaction with the neighbouring resonance state converged to 3d^2(^1G4) of Sc^+. 相似文献
780.
We propose a method based on cluster expansion to study the truncated correlations of unbounded spin systems uniformly in the boundary condition and in a possible external field. By this method we study the spin–spin truncated correlations of various systems, including the case of infinite range simply integrable interactions, and we show how suitable boundary conditions and/or external fields may improve the decay of the correlations. 相似文献