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Liu Chao

Publications and source records attributed to Liu Chao.

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A method for statistical research on binary stars using radial velocities

Binary stars are fundamental to astrophysics, providing critical insights into stellar evolution, galactic dynamics, and fundamental physics. However, the high dimensionality of orbital parameters and observational constraints present significant challenges in statistically characterizing their properties. In this study, we propose and implement a novel algorithm, the Differential Velocity Cumulative Distribution (DVCD), to analyze binary star systems using radial velocity data. The DVCD method demonstrates superior accuracy and computational efficiency compared to existing approaches, reducing computation time by factors of $10^{-4}$ to $10^{-5}$ under comparable conditions. We applied the DVCD algorithm to red giant samples from APOGEE DR16, dividing the dataset into 16 subsets based on $\log g$ and M/H. Our findings reveal that the binary fraction decreases with decreasing surface gravity and increasing metallicity, offering valuable constraints on the evolutionary processes of binary stars. This study underscores the potential of the DVCD method for large-scale statistical analyzes of binary systems.

astro-ph.SR

Ricci Flow method in the existence problem of the K"ahler-Einstein metrics

This note illustrates the Ricci flow method based on the Cao.H.D's paper[1] and Yau.S.T's paper[4], and tries to explain the method in detail, especially in some calculations. Jian Song and Weinkove's note[9] used some other estimates to obtain the result, this paper will explain some of their estimates as well. This note was a seminar lecture note in 2022 summer when the author was giving lectures on the geometry analysis seminar reasearching the Ricci flow method. The part of the imporatnt zero order estimate is going to be added in a few days. The level of the author is limited, if there are any errors, please do not hesitate to advise. Any comments will be grateful.

math.AP

Effects of the Functional Group on the Lithium Ions Across the Port of Carbon Nanotube

The mean axial velocity of lithium irons across the entrance of carbon nanotube VLi is an important factor for the charge-discharge performances of rechargeable Lithium battery. The molecular dynamics simulation method is adopted to evaluate the factors and their effects on VLi which include the diameter of carbon nanotube, functional group type on the port and the number of a given type of functional group. The statistical analysis of the calculation results shows that: In the selected carbon nanotubes of four different diameters, VLi will gradually rise with the increase of CNT diameter due to lithium irons migration resistance decreasing; as the port of CNT is successively modified to hydrogen (-H), hydroxyl (-OH), amino (-NH2) and carboxyl (-COOH), the corresponding migration resistance of lithium ions is enhanced resulting in the dropping of VLi; in comparison to the effect strength of four types of functional groups on VLi, -COOH shows strongest, -NH2 and -OH perform relatively weaker, and the effect difference between -NH2 and -OH is very small, -H displays weakest; When the number of a given non-hydrogen functional group on the port sequentially increases, it also shows a trend that lithium ion migration resistance gradually increases which makes VLi decreases in turn. The more influential the functional group, the greater the impact of functional group number changes on VLi. The results of this paper have some significance on the precise production of lithium-ion battery electrode materials, enhancing the overall battery cycle efficiency and charging speed.

physics.comp-ph

Toda-like systems: solutions and symmetries

This report is consisted of six independent chapters, each chapter (except chapter 1) is a paper carried out in colabouration with others, who's names are indicated in chapter1. The topics included are (1)Overview of general properties of Toda-like systems (chapter1) (2)Free field representations of some particular example of entended Toda like system via Drinfeld-Sokolov construction (chapter2) (3)Heterotic conformal Toda system (chapter3) (4)Heterotic Liouville systems related to Bernoulli equation (chapter4) (5)Two-extended Toda field in three-dimensions--a representative example of extended Toda systems in higher dimensions (chapter5) and (6) $W_N^{(l)}$ algebras in the exchange algebra's framework (chapter6)

hep-th