Application of the characteristic CIP method to a shallow water model on the sphere

Semi-implicit algorithms are popularly used to deal with the gravitational term in numerical models. In this paper, we adopt the method of characteristics to compute the solutions for gravity waves on a sphere directly using a semi-Lagrangian advection scheme instead of the semi-implicit method in a shallow water model, to avoid expensive matrix inversions. Adoption of the semi-Lagrangian scheme renders the numerical model always stable for any Courant number, and which saves CPU time. To illustrate the efficiency of the characteristic constrained interpolation profile (CIP) method, some numerical results are shown for idealized test cases on a sphere in the Yin-Yang grid system.

基于正位网格的局部时空守恒格式

时空守恒元-解元(CE/SE)方法是近十年来发展起来的一种新的数值算法,最早是由NASALewis研究中心的Chang及其合作者提出的,后来由张增产和王刚等人对该方法进行了改进。理论和实际计算都证明该算法有很高的精度,特别擅长于求解守恒型方程。但是目前该算法只有少数几个版本的格式,这是因为为了保证全局时空守恒,现有格式都采用了在时间方向上相互交错的网格,这就大大限制了格式的灵活性。为此,本文对CE/SE方法进行了改进,得到了一种基于正位网格的局部时空守恒格式(LSTC)。该格式在应用中变得更简洁,最重要的是为时空守恒格式的发展提供了新的思路。不仅如此,该格式还继承了CE/SE方法几乎所有的特点和优点:1.将时间和空间统一起来同等对待;2.把流场物理量及其空间导数作为独立未知量同时求解;3.在推广到多维时无需使用算子分裂或方向交替技术,是一种真正意义上的多维算法;4.捕捉激波不需要Riemann求解器,激波分辨率高,在间断处能有效抑制非物理振荡。

Multiple expansions of C-4 plant biomass in East Asia since 7 Ma coupled with strengthened monsoon circulation

IEECAS SKLLQG

Formation of the Yazi Spring Stream and its significance on tectonics-climate on the northern slope of Kunlun Mountains

IEECAS SKLLQG

Magnetic properties of Jiaxian red clay sequences from northern Chinese Loess Plateau and its paleoclimatic significance

IEECAS SKLLQG

20—50MeV O5+离子引起Au的L壳层X射线产生截面研究

在北京13 MV串列加速器上利用20—50MeV O5+离子研究Au的L壳层X射线产生截面. 实验结果表明σ（Ll）/σ（Lα） ，σ（Lβ）/σ（Lα） 和σ（Lγ）/σ（Lα）与EＣＰSSR理论计算结果符合比较好.在实验中由于较高的能量,在能量点存在能移现象.

Faddeev-Jackiw canonical path integral quantization for a general scenario, its proper vertices and generating functionals

We generalize the Faddeev-Jackiw canonical path integral quantization for the scenario of a Jacobian with J=1 to that for the general scenario of non-unit Jacobian, give the representation of the quantum transition amplitude with symplectic variables and obtain the generating functionals of the Green function and connected Green function. We deduce the unified expression of the symplectic field variable functions in terms of the Green function or the connected Green function with external sources. Furthermore, we generally get generating functionals of the general proper vertices of any n-points cases under the conditions of considering and not considering Grassmann variables, respectively; they are regular and are the simplest forms relative to the usual field theory.

Cross-correlation of excitation functions for different fragments and different scattering angles in Al-27(F-19, x)y reactions

Excitation functions have been measured for different projectile-like fragments produced in Al-27(F-19,x)y reactions at incident energies from 110.25 to 118.75 MeV in 250 keV steps. Strong cross section fluctuations of the excitation functions are observed. The cross- correlation coefficients of the excitation functions for different atomic number Z and for different scattering angle theta(cm) have been deduced. These coefficients are much larger than the statistical theoretical calculated ones. This indicates that there are strong correlations between different exit channels in the dissipative heavy ion Collision of Al-27(F-19,x)y.

(PF2)-P-3 neutron superfluidity in neutron stars and three-body force effect

We investigate the (PF2)-P-3 neutron superfluidity in beta-stable neutron star matter and neutron stars by using the BCS theory and the Brueckner-Hartree-Fock approach. We adopt the Argonne V-18 potential supplemented with a microscopic three-body force as the realistic nucleon-nucleon interaction. We have concentrated on studying the three-body force effect on the (PF2)-P-3 neutron pairing gap. It is found that the three-body force effect is to enhance remarkably the (PF2)-P-3 neutron superfluidity in neutron star matter and neutron stars.

Superfluidity in neutron matter and symmetric nuclear matter and the effect of a microscopic three-body force

The neutron (PF2)-P-3 pairing gap in pure neutron matter, neutron (PF2)-P-3 gap and neutron-proton (SD1)-S-3 gap in symmetric nuclear matter have been studied by using the Brueckner-Hartree-Fock(BHF) approach and the BCS theory. We have concentrated on investigating and discussing the three-body force effect on the nucleon superfluidity. The calculated results indicate that the three-body force enhances remaxkably the (PF2)-P-3 superfluidity in neutron matter. It also enhances the (PF2)-P-3 superfluidity in symmetric nuclear matter and its effect increases monotonically as the Fermi-momentum k(F) increases, whereas the three-body force is shown to influence only weakly the neutron-proton (SD1)-S-3 gap in symmetric nuclear matter.