Spectral Element Viscosity Methods for Nonlinear Conservation Laws onthe Semi-Infinite Interval

In this paper we propose a spectral element: vanishing viscosity (SEW) method for the conservation laws on the semi-infinite interval. By using a suitable mapping, the problem is first transformed into a modified conservation law in a bounded interval, then the well-known spectral vanishing viscosity technique is generalized to the multi-domain case in order to approximate this trarsformed equation more efficiently. The construction details and convergence analysis are presented. Under a usual assumption of boundedness of the approximation solutions, it is proven that the solution of the SEW approximation converges to the uniciue entropy solution of the conservation laws. A number of numerical tests is carried out to confirm the theoretical results.     

On Spin Structures and Dirac Operators on the Noncommutative Torus

We find and classify possible equivariant spin structures with Dirac operators on the noncommutative torus, proving that, similarly as in the classical case, the spectrum of the Dirac operator depends on the spin structure.     

钒氧酞菁多晶薄膜的稳态光电压特性研究

报道了Ａｌ／ＶＯＰｃ／ＩＴＯ夹心结构在稳态连续光照射下的光电压作用谱，稳态光电压作用谱不仅依赖于照射光的波长，而且依赖于ＶＯＰｃ（钒氧酞菁）多晶薄膜的堆积方式，对ＶＯＰｃ在相１，相１１，及α型三种堆积方式的稳态电压波长响应进行了研究，并对其内在机制作了初步探讨。     

The use of Chebyshev Polynomials in the space-time least-squares spectral element method

Chebyshev polynomials of the first kind are employed in a space-time least-squares spectral element formulation applied to linear and nonlinear hyperbolic scalar equations. No stabilization techniques are required to render a stable, high order accurate scheme. In parts of the domain where the underlying exact solution is smooth, the scheme exhibits exponential convergence with polynomial enrichment, whereas in parts of the domain where the underlying exact solution contains discontinuities the solution displays a Gibbs-like behavior. An edge detection method is employed to determine the position of the discontinuity. Piecewise reconstruction of the numerical solution retrieves a monotone solution. Numerical results will be given in which the capabilities of the space-time formulation to capture discontinuities will be demonstrated.     

The stochastic Liouville equation and Padé approximants

The applicability of Padé approximant techniques to solving the stochastic Liouville equation is discussed. The special case of an axially symmetric spin system undergoing isotropic Brownian motion is studied. Two types of expansions are explored which yield efficient algorithms for spectral simulations.     

快速推求等效组态的原子谱项

本文根据置换群方法，运用Ｃ语言编制了计算程序，可快速、准确地推求等效组态ｓ＾Ｎ、ｐ＾Ｎ、ｄ＾Ｎ、ｆ＾Ｎ、…ｘ＾Ｎ、ｙ＾Ｎ、ｚ＾Ｎ的原子谱项。     

400GeV/c pp碰撞多粒子产生的分形行为

对400GeV/cpp碰撞产生的带电粒子赝快度分布的实验数据用G矩方法进行了多重分形分析.在分割代数v很小的情况下得到的广义维数是不同的(1>D0>D1>D2…);谱函数是光滑的,凹面向下,在α0时为峰值;重新标度后的谱函数大在时具有普适性.这些结果与其它实验是一致的.     

Estimation of the Dynamics of the Drift of Spectral Lines and Computer Correction of the Scan of a Mass Spectrum

This article describes the technique used to estimate the temporal positions of spectral lines of a quadrupole mass spectrometer and to automatically determine mass numbers without resorting to reference substances, as well as the algorithms of digital registration of mass spectra and the technical means of an experimental automated system based on a serial MX-7304A mass spectrometer and a personal computer. The results of experimental investigations of the dynamics of the drift of peaks and the results of tests of the technique under real conditions are given. The error in determining the atomic mass unit (u) by the technique developed was not higher than 0.01%.     

Heat Content Asymptotics for Operators of Laplace Type with Spectral Boundary Conditions

Let P be an operator of Dirac type and let D=P ² be the associated operator of Laplace type. We impose spectral boundary conditions and study the leading heat content coefficients for D.