无规取向、无吸收非球形粒子光散射的T-矩阵方法     

丁继烈  许丽生 《成都信息工程学院学报》2001,16(3):159-168

较详细地研究了无规取向、无吸收椭球体粒子的T－矩阵收敛问题。首先，简要概括了nmax的3种收敛方案和它们的基本特性。然后，应用1993年提出的数学收敛方法（M－方法）和1998年提出和物理收敛方法（P－方法）研究收敛问题。结果表明椭球粒子收敛精度对粒子的尺度参数，纵横比以及椭球体的种类（例如，长／扁椭球）有很强的依赖性。当粒子的尺度参数不太大时，甚至在极端纵横比的条件下，P－收敛方案优于M－收敛方案。  相似文献   

小旋转椭球粒子群的微波衰减系数与雷达反射率因子之间的关系   总被引：6，自引：1，他引：5  

王振会  张培昌 《气象学报》2000,58(1):123-128

通过模拟及取样导出了小旋转椭球粒子群旋转轴呈 3种不同取向 ,而入射电磁波分别为水平发射水平偏振波及水平发射垂直偏振波时的衰减系数与雷达反射率因子之间的关系 ,获得 3种波长的具体表达式 ,并对结果作了物理分析。所得结果可直接用于雷达定量测量降水时的衰减订正。  相似文献   

Dirac spinor scattering states with positive-energy in rotating spheroid models     

Zhi-Fu Gao  Ci-Xing Chen  Na Wang  Xin-Jun Zhao  Zhao-Jun Wang 《Astronomische Nachrichten》2024,345(2-3):e240012

There are many rotating spheroids in the universe, and many astronomers and physicists have used theoretical methods to study the characteristics of stellar gravity since Newton's time. This paper derives the solutions of eight scattering states $({\varphi }^{(0)},{\chi }^{(0)},{\varphi }^{(1)},{\chi }^{(1)},{\varphi }^{(2)}$, ${\chi }^{(2)},{\varphi }^{(3)}$, and ${\chi }^{(3)})$ for the Dirac equation with positive-energy $E=\mathit{im}$, and establishes the relationship between the differential scattering cross section ${\sigma }_i(p,\theta ,\phi )$ and the stellar density $\mu$. It is found that: (1) For the eight scattering states, their average scattering cross-sections $\overline{{\sigma }_i}$ are proportional to ${\mu }^2$, and depend on the star's radius, and the higher the stellar density $\mu$, the greater the sensitivity of $\overline{\sigma \mathit{i}}$ to the change of $\mu$; (2) For the four scattering states ${\chi }^{(i)},i=0,1,2,3$, their average scattering amplitudes $\bar{f}(p,\theta )$ and $\bar{\sigma }(p,\theta )$ depend on the mass $m$ of the particles; while for the other four scattering states ${\varphi }^{(i)}$, $i=0,1,2,3$, then $\bar{f}$ and $\bar{\sigma }$ are independent of $m$. This study links the gravitational characteristics of stars with the scattering cross section, creating a new method for studying the gravitational characteristics, which helps to reveal the mystery of the gravity of rotating ellipsoidal stars.  相似文献   

Rotating Stratified Heterogeneous Oblate Spheroid in Newtonian Physics     

E.P. Esteban  S. Vazquez 《Celestial Mechanics and Dynamical Astronomy》2001,81(4):299-312

By solving the Euler hydrodynamical equations we have obtained closed form solutions for the angular velocities and pressures of a three stratified non-confocal heterogeneous oblate spheroid. Limiting and particular solutions cases, such as a spheroid with N layers, a stratified spheroid with the same eccentricities, as well as confocal layered spheroids are also explicitly written down. As an application, we have numerically estimated planet Earth's outer and inner cores' ellipticities to be _o=1/413.318 and _i=1/424.616, respectively. These Earth's ellipticities values are in good agreement with those found in the literature.  相似文献