Based on the nonlinear equations of the theory of densitywave, the evolutionary direction and the observable conditions on spiral galaxies may be derived by the qualitative analysis theory.
基于密度波理论的非线性方程，用定性分析理论可导出旋涡星系的演化方向和由观测可得到的演化条件。
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The paper introduces the present knowledge of the theory and technology of diffusion photon densitywave (DPDW) which have been focus of the recent research.
The structural stabilities and electronic structures of W atomic chains are studied by employing first-principles plane wave pseudopotential method based on the density functional theory.