An Estimation of the Lower Bound on the Extragalactic TeV γ-ray Background     

《Chinese Astronomy and Astrophysics》2022,46(2):42-54

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An Algorithm on the Numerical Continuation of Asymmetric and Symmetric Periodic Orbits Based on the Broyden’s Method and Its Application     

《Chinese Astronomy and Astrophysics》2022,46(4):450-470

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Inflation in mimetic f(R,T) gravity     

《New Astronomy》2022

In this paper, we employ mimetic $f(R,T)$ gravity coupled with Lagrange multiplier and mimetic potential to yield viable inflationary cosmological solutions consistent with latest Planck and BICEP2/Keck Array data. We present here three viable inflationary solutions of the Hubble parameter ($H$) represented by $H\left(N\right)={(A\exp \beta N+B{\alpha }^N)}^{\gamma }$, $H\left(N\right)={(A{\alpha }^N+B\log N)}^{\gamma }$, and $H\left(N\right)={(A{e}^{\beta N}+B\log N)}^{\gamma }$, where $A$, $\beta$, $B$, $\alpha$, $\gamma$ are free parameters, and $N$ represents the number of e-foldings. We carry out the analysis with the simplest minimal $f(R,T)$ function of the form $f(R,T)=R+\chi T$, where $\chi$ is the model parameter. We report that for the chosen $f(R,T)$ gravity model, viable cosmologies are obtained compatible with observations by conveniently setting the Lagrange multiplier and the mimetic potential.  相似文献   

Research on the Intra-Group Light in the HCG 95 Group.     

《Chinese Astronomy and Astrophysics》2022,46(4):391-404

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基于微控制器数字硬件实现的网格涡卷超混沌系统          下载免费PDF全文

徐煜明  包伯成  徐强 《海洋学报》2010,32(9):5959-5965

基于微控制器(MCU)设计了一个通用的四维混沌系统数字硬件实验电路,由此实现了9×7网格涡卷的混沌和超混沌吸引子的生成.本文基于由Colpitts振荡器模型延伸出的四维多涡卷超混沌系统,通过引入单位锯齿波函数替换原系统中的三角波函数,构建了一个便于MCU数字硬件实现的新的网格涡卷超混沌系统,并对新系统网格涡卷吸引子的形成机理进行了分析和数值仿真.通过采用Euler算法对新系统进行离散化,在实验电路的有效动态范围内可以生成比原系统更多网格涡卷数量的吸引子.实验结果有效验证了本文基于MCU实现的网格涡卷超混沌  相似文献   

基于非抽取小波变换贝叶斯估计的水下红外图像去噪     

卢明波  周军 《海洋技术学报》2010,29(1)

利用非抽取小波变换的平移不变性和冗余性的特点,在贝叶斯估计下,结合广义高斯分布(GGD)对小波系数进行建模,构造了一个基于拉普拉斯分布的MapShrink子带自适应图像去噪算法和阈值函数。对HH1子带小波系数进行2j抽取,并估计噪声方差,该算法有效地抑制了伪吉布斯现象。仿真结果表明,利用新算法进行水下红外图像去噪,在信噪比增益和最小均方误差意义上均优于传统的Bayesian去噪方法。  相似文献   

Equilibrium points and Lyapunov families in the circular restricted three-body problem with an oblate primary and a synchronous rotating dipole secondary: Application to Luhman-16 binary system     

《New Astronomy》2024

We numerically study a version of the synchronous circular restricted three-body problem, where an infinitesimal mass body is moving under the Newtonian gravitational forces of two massive bodies. The primary body is an oblate spheroid while the secondary is an elongated asteroid of a combination of two equal masses forming a rotating dipole which is synchronous to the rotation of the primaries of the classic circular restricted three-body problem. In this paper, we systematically examine the existence, positions, and linear stability of the equilibrium points for various combinations of the model's parameters. We observe that the perturbing forces have significant effects on the positions and stability of the equilibrium points as well as the regions where the motion of the particle is allowed. The allowed regions of motion as determined by the zero-velocity surface and the corresponding isoenergetic curves as well as the positions of the equilibrium points are given. Finally, we numerically study the binary system Luhman-16 by computing the positions of the equilibria and their stability as well as the allowed regions of motion of the particle. The corresponding families of periodic orbits emanating from the collinear equilibrium points are computed along with their stability properties.  相似文献