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501.
考虑具有周期传染率和垂直传染的S IR流行病模型,分析了该模型的动力学性态.对小振幅的周期垂直传染率模型,给出了模型周期解的近似表达式,证明了该周期解的稳定性,并做了数值模拟,显示出周期解可能是全局稳定的. 相似文献
502.
Using simulated Tianqin gravitational wave data and electromagnetic wave data to study the coincidence problem and Hubble tension problem 下载免费PDF全文
In this study, we used electromagnetic wave data (H0LiCOW, \begin{document}$ H(z) $\end{document} ![]()
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, SNe) and gravitational wave data (Tianqin) to constrain the interacting dark energy (IDE) model and investigate the Hubble tension and coincidence problems. By combining these four types of data (Tianqin+H0LiCOW+SNe+\begin{document}$ H(z) $\end{document} ![]()
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), we obtained the following parameter values with a confidence interval of \begin{document}$ 1\sigma $\end{document} ![]()
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: \begin{document}$ \Omega_m=0.36\pm0.18 $\end{document} ![]()
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, \begin{document}$ \omega_x=-1.29^{+0.61}_{-0.23} $\end{document} ![]()
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, \begin{document}$ \xi=3.15^{+0.36}_{-1.1} $\end{document} ![]()
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, and \begin{document}$H_0=70.04\pm $\end{document} ![]()
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\begin{document}$ 0.42~ {\rm kms}^{-1}{\rm Mpc}^{-1}$\end{document} ![]()
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. According to our results, the best value of \begin{document}$ H_0 $\end{document} ![]()
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shows that the Hubble tension problem can be alleviated to some extent. In addition, the center value of \begin{document}$ \xi+3\omega_x = -0.72^{+2.19}_{-1.19}(1\sigma) $\end{document} ![]()
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indicates that the coincidence problem is slightly alleviated. However, \begin{document}$ \xi+3\omega_x = 0 $\end{document} ![]()
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is still within the \begin{document}$ 1\sigma $\end{document} ![]()
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error range, which indicates that the ΛCDM model is still the model in best agreement with the observational data at present. Finally, we compared the constraint results of the electromagnetic and gravitational waves on the model parameters and found that the constraint effect of electromagnetic wave data on model parameters is better than that of simulated Tianqin gravitational wave data. 相似文献
503.
504.
Masahide Ohno 《Journal of Electron Spectroscopy and Related Phenomena》2008,162(3):134-145
The relative spectral intensity of the band-like two M4,5-hole state to the atomic-like localized one is much suppressed in the coincidence M3–M4,5M4,5 super Coster–Kronig (sCK) electron spectrum of Cu metal compared to the one in the coincidence L3–M4,5M4,5 Auger electron spectroscopy (AES) spectrum. The M3-hole lifetime width of Cu metal is calculated by an ab initio atomic many-body theory (the extended relaxed core random phase approximation with exchange). The calculated M3-hole lifetime width of Cu metal agrees well with the experimental one. The M3–M4,5M4,5 sCK decay width of Cu metal decreases much with delocalization of the two M4,5 holes in the sCK final state, whereas the Auger decay width is fairly independent of localization and delocalization of the two M4,5 holes in the Auger final state. Thus, the relative spectral intensity of the band-like state is much suppressed in the coincidence M3–M4,5M4,5 sCK-electron spectrum of Cu metal compared to the one in the coincidence L3–M4,5M4,5 AES spectrum. 相似文献
505.
Doppler broadening and coincidence Doppler broadening of annihilation radiation experiments have been performed in three kinds of polyethylene glycol(PEG) membrane formed with different average molecular weight using the tunable monoenergy slow positron probe as a function of implantion energy. The obtained positron annihilation parameters are interpreted from two aspects: surface effect and differences in micro-structure or chemical environment of positron annihilation. The experimental results show that the regulation of densification of PEG molecular packing and distribution uniformity from the near surface layer to the bulk region in the film forming process can be well realized by changing its molecular weight. Combining a variable monoenergetic slow positron beam and these two positron annihilation spectroscopy methods is a powerful tool to study positron annihilation characteristics and for polymeric thin-film fine structure analysis. 相似文献
506.
通过70As的放射性衰变研究了70Ge的激发态,新发现能量为1 036.99,1 196.66,1 539.29和2 531.7 keV的四条新γ射线,重新确认了2 219.34 keV γ射线的跃迁位置,新确认496.74,1 295.24和1 417.24 keV这三条γ射线首次放入衰变纲图,本工作证实了1 881.67,2 325.42和2 424.41 keV γ射线的跃迁位置,建议了能量为4 243.10和5 265.81 keV的两个新能级,建立了新的衰变纲图,基于比较半衰期和γ跃迁分支比建议了一些能级的自旋-宇称。The excited states of the 70Ge nucleus are investigated in radioactive decay of the 70As. Four new transitions with 1 036.99, 1 196.66, 1 539.29 and 2 531.7 keV are found for the first time. The position of 2 219.34 keV transition are reassigned, the transition positions of 496.74, 1 295.24 and 1 417.24 keV γ-rays are assigned for the first time, and the placements of 1 881.67, 2 325.42 and 2 424.41 keV γ-rays are confirmed in the present work. Two new levels, at 4 243.10 and 5 265.81 keV excitation energy, respectively, are proposed. The decay scheme is established and for a number of levels spin-parity assignments are suggested on the basis of logft values and γ-branching ratios. 相似文献
507.
端粒酶是一种逆转录酶,能够维持端粒的长度和活性,从而防止染色体末端降解或融合,维持染色体稳定.大多数正常体细胞中端粒酶活性被抑制,端粒长度随着细胞持续分裂逐渐缩短;而在大多数癌细胞中端粒酶都表现出活性,端粒的长度和结构得以维持,癌细胞永生化.由此可见端粒酶是一种重要的癌症标志物,可作为癌症诊断依据和治疗靶点.然而,端粒酶结构复杂且数量少,难以从微量全酶复合物中分离出足量端粒酶用于分析,这为传统方法研究端粒酶带来极大困难.随着单分子荧光技术的发展,荧光共振能量转移、荧光双色同步响应等技术已被应用于端粒酶的研究,打破了传统方法检测端粒酶的各种局限.本文主要综述了单分子荧光技术的发展,端粒、端粒酶与癌症及其研究进展,并对单分子荧光技术在端粒酶研究中的应用及其发展趋势进行了总结和展望. 相似文献
508.
A class of oscillator of the El Ni?o-Southern
oscillation model is considered. Using Mawhin's continuation
theorem, a result on the existence of periodic solutions for ENSO
model is obtained. 相似文献
509.
Section theorems,coincidence theorems and intersection theorems on H-spaces with applications 总被引:3,自引:0,他引:3
The purpose of this paper is to study the section theorems, coincidence theorems and intersection theorems on H-spaces. As a way of application, we use these results to study the existence problems of solutions for minimax inequalities and variational inequalities. The results presented in this paper improve and extend the corresponding results in [1, 3, 5, 6, 8, 9, 12, 14,15, 17] 相似文献
510.
龚循华 《南昌大学学报(理科版)》1991,15(2):1
本文在较弱的条件下推广和改进了K.Fan的零点存在性定理与重合定理,同时也改进了K.K.Tan的一个主要引理 相似文献