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Search Results: 1 - 10 of 104178 matches for " Yuexing Zhang "
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Abundant Lump Solutions and Interaction Phenomena to the Kadomtsev-Petviashvili-Benjamin-Bona-Mahony Equation  [PDF]
Jianqing Lü, Sudao Bilige, Xiaoqing Gao, Yuexing Bai, Runfa Zhang
Journal of Applied Mathematics and Physics (JAMP) , 2018, DOI: 10.4236/jamp.2018.68148
Abstract:
In this paper, we obtained a kind of lump solutions of the Kadomtsev-Petviashvili-Benjamin-Bona-Mahony (KP-BBM) equation with the assistance of Mathematica. Some contour plots with different determinant values are sequentially made to show that the corresponding lump solutions tend to zero when x2+y2→∞. Particularly, lump solutions with specific values of the include parameters are plotted, as illustrative examples. Finally, a combination of stripe soliton and lump soliton is discussed to the KP-BBM equation, in which such a solution presents two different interesting phenomena: lump-kink and lump-soliton. Simultaneously, breather rational soliton solutions are displayed.
A Real-time Two-way Authentication Method Based on Instantaneous Channel State Information for Wireless Communication Systems
Xiangyu Lu,Yuyan Zhang,Yuexing Peng,Hui Zhao
Journal of Communications , 2011, DOI: 10.4304/jcm.6.6.471-476
Abstract: Traditional solutions handle security at the application layer, which causes huge signaling overhead and long delay if authentication is implemented for every signal to enhance the security of wireless communication systems. In this paper, a realtime and two-way authentication method is proposed, which is based on the characteristics of radio channel including randomness and privacy. For the proposed method, the unique instant channel state information (CSI) can be used to authenticate the transmitter. In frequency- and time-selective fading channels, the current estimated CSI is compared with the predicted CSI, which is implemented at the previous frame, in order to authenticate the validation of the received signal. Both the hypothesis testing and mutual information measure methods are used for authentication determination, and the Mont Carlo simulation results verify the efficiency of the proposed method.
Accretion onto Intermediate-mass Seed Black Holes in Primordial Galaxies
Yuexing Li
Physics , 2011,
Abstract: The origin of the supermassive black holes that power the most distant quasars observed is largely unknown. One hypothesis is that they grew rapidly from intermediate-mass seeds (~100 M_sun) left by the first stars. However, some previous studies argued that accretion onto these black holes was too low to build up the mass due to strong suppression by radiative feedback. Here, we re-exam the accretion process of such a black hole embedded in a primordial gas cloud, by considering a wide range of physical and numerical parameters not explored before. We find that, while radiative heating and pressure indeed suppress accretion effectively, self-gravity of the gas eventually overcomes the feedback effects and boosts the accretion to the Eddington rate after one free-fall timescale of the cloud. Moreover, for a given black hole mass, there exists a critical density above which the accretion can reach Eddington limit. Furthermore, we find a universal correlation between black hole accretion rate and ambient gas density, which may serve as a realistic recipe for black hole growth in simulations.
Alterations in cell growth and signaling in ErbB3 binding protein-1 (Ebp1) deficient mice
Yuexing Zhang, Yan Lu, Hua Zhou, Myounghee Lee, Zhenqiu Liu, Bret A Hassel, Anne W Hamburger
BMC Cell Biology , 2008, DOI: 10.1186/1471-2121-9-69
Abstract: Ebp1-/- mice were on average 30% smaller than wild type and heterozygous sex matched littermates. Growth retardation was apparent from Day 10 until Day 30. IGF-1 production and IGBP-3 and 4 protein levels were reduced in both embryo fibroblasts and adult knock-out mice. The proliferation of fibroblasts derived from Day 12.5 knock out embryos was also decreased as compared to that of wild type cells. Microarray expression analysis revealed changes in genes important in cell growth including members of the MAPK signal transduction pathway. In addition, the expression or activation of proliferation related genes such as AKT and the androgen receptor, previously demonstrated to be affected by Ebp1 expression in vitro, was altered in adult tissues.These results indicate that Ebp1 can affect growth in an animal model, but that the expression of proliferation related genes is cell and context specific. The Ebp1-/- mouse line represents a new in vivo model to investigate Ebp1 function in the whole organism.Members of the ErbB receptor tyrosine kinase family (ErbB1-4) and their ligands are important regulators of cell growth and differentiation. Studies of ErbB1, ErbB2 and heregulin (the ErbB3/4 ligand) deficient mice indicate that these genes are essential for embryonic development [1]. In turn, the activity of the ErbB receptors is regulated by their interacting partners. An ErbB3 binding protein (Ebp1) was cloned in our laboratory during a yeast two-hybrid screen [2]. Ebp1 is identical to the murine p38-2G4 protein which was isolated as a DNA binding protein[3]. These proteins are members of the Proliferation-associated 2G4 (Pa2g4) gene family, which is highly conserved throughout evolution [4]. More than 30 genes encoding proteins homologous to Ebp1 have been found in organisms ranging from Danio rerio to Pan troglodytes [5].Ebp1 is expressed in mammalian cell lines derived from multiple origins. Ebp1 mRNA is also found in all normal adult human and murine tissues examin
Potential Symmetries, One-Dimensional Optimal System and Invariant Solutions of the Coupled Burgers’ Equations  [PDF]
Yuexing Bai, Sudao Bilige, Temuer Chaolu
Journal of Applied Mathematics and Physics (JAMP) , 2018, DOI: 10.4236/jamp.2018.69156
Abstract: In this paper, we discuss one-dimensional optimal system and the invariant solutions of Coupled Burgers’ equations. By using Wu-differential characteristic set algorithm with the aid of Mathematica software, the classical symmetries of the Coupled Burgers’ equations are calculated, and the one-dimensional optimal system of Lie algebra is constructed. And we obtain the invariant solution of the Coupled Burgers’ equations corresponding to one element in one dimensional optimal system by using the invariant method. The results generalize the exact solutions of the Coupled Burgers’ equations.
Effects of photon trapping on the Lyman-alpha properties of star-forming galaxies
Hidenobu Yajima,Yuexing Li
Physics , 2012, DOI: 10.1093/mnras/stt2205
Abstract: Recent observations show that a large number of Lyman-alpha emitters (LAEs) at high redshift z >= 3 have unusually high Lya equivalent widths (EW > 400 angstrom). However, the origin of these high EWs is an open question. Here, we investigate the impacts of photon trapping on the Lya EW and other properties by tracking the Lya radiative transfer in spherical galactic clouds. We find that the delayed escape of the Lya photons can change the Lya properties significantly. During the transition phase from optically thick to optically thin where the Lya photons can escape simultaneously, the EW can be boosted to ~ 1000 angstrom, the Lya luminosity can be increased by a factor of a few, and the line profile can be significantly broadened. The boost factor appears to depend on the galaxy properties such as mass and star formation rate and timescale, therefore future investigation combing 3D Lya RT calculations with cosmological simulations of galaxy formation and evolution is needed to fully understand the Lya properties of early star-forming galaxies.
Distinctive 21 cm structures of the first stars, galaxies, and quasars
Hidenobu Yajima,Yuexing Li
Physics , 2013, DOI: 10.1093/mnras/stu1982
Abstract: Observations of the redshifted 21 cm line with upcoming radio telescopes promise to transform our understanding of the cosmic reionization. To unravel the underlying physical process, we investigate the 21 cm structures of three different ionizing sources, Population (Pop) III stars, the first galaxies, and the first quasars, by using radiative transfer simulations that include both ionization of neutral hydrogen and resonant scattering of Lya photons. We find that Pop III stars and quasars produce a smooth transition from an ionized and hot state to a neutral and cold one, owing to their hard spectral energy distribution with abundant ionizing photons, in contrast to the sharp transition in galaxies. Furthermore, Lya scattering plays a dominant role in producing the 21 cm signal as it determines the relation between hydrogen spin temperature and gas kinetic temperature. This effect, also called Wouthuysen-Field coupling, depends strongly on the ionizing source. It is the strongest around galaxies, where the spin temperature is highly coupled to that of the gas, resulting in extended absorption troughs in the 21 cm brightness temperature. On the other hand, in the case of Pop III stars, the 21 cm signal shows both emission and absorption regions around a small HII bubble. For quasars, a large emission region in the 21 cm signal is produced, and the absorption region decreases as the size of the HII bubble becomes large due to the limited traveling time of photons. We predict that future surveys from large radio arrays such as MWA, LOFAR and SKA may be able to detect the 21 cm signals of primordial galaxies and quasars, but not likely Pop III stars due to its small angular diameter.
Application of the Generalized Simplest Equation Method to the Burgers Equation  [PDF]
Yuexing Bai, Sudao Bilige, Xiaoqing Gao, Jianqing Lü
Journal of Applied Mathematics and Physics (JAMP) , 2017, DOI: 10.4236/jamp.2017.51011
Abstract: We successfully constructed wide classes of exact solutions for the Burgers equation by using the generalized simplest equation method. This method yielded a Bäcklund transformation between the Burgers equation and a related constraint equation. By dealing with the constraint equation, we obtained the traveling wave solutions and non-traveling wave solutions of the Burgers equation.
Effect of preparation methods on the adsorption propertyof municipal solid waste-based carbon materials
Song MinTang XinhongTang MeiWei Yuexing
- , 2016, DOI: 10.3969/j.issn.1003-7985.2016.02.013
Abstract: Three different preparation methods including steam physical activation, catalytic carbonation and KOH chemical activation methods were used to prepare municipal solid waste-based carbon materials. The methylene blue(MB)adsorption value was applied to evaluate the adsorption capabilities of the prepared carbon materials. The effects of preparation methods on adsorption capability and yield of products were investigated. The yield of carbon materials with the catalytic carbonation method is the highest, and the KOH activation method is the second level. Considering the adsorption performance, the KOH activation method is much more favorable. Among the different components of municipal solid waste-based carbon materials, the adsorption properties of the single component of paperboard, the double components of tire and paperboard, the triple components of tire, paperboard and polyvinyl chloride(PVC), and the multi-component mixtures are better than those of other single-, double-, triple- and multi-component mixtures, respectively.
Scaling Relations Between Low-mass Black Holes and Their Host Galaxies
Qirong Zhu,Yuexing Li,Sydney Sherman
Physics , 2012,
Abstract: It is well established that supermassive black holes in nearby elliptical galaxies correlate tightly with the kinematic property ($\mbhsigma$ correlation) and stellar mass ($\mbhhost$ correlation) of their host spheroids. However, it is not clear what the relations would be at the low-mass end, and how they evolve. Here, we investigate these relations in low-mass systems ($\MBH \sim \rm{10^{6}- 10^{8}}\, \Msun$) using the Aquila Simulation, a high-resolution cosmological hydrodynamic simulation which follows the formation and evolution of stars and black holes in a Milky Way-size galaxy and its substructures. We find a number of interesting results on the origin and evolution of the scaling relations in these systems: (1) there is a strong redshift evolution in the $\mbhsigma$ relation, but a much weaker one in the $\mbhhost$ relation; (2) there is a close link between the $\mbhsigma$ relation and the dynamical state of the system -- the galaxies that fall on the observed correlation appear to have reached virial equilibrium. (3) the star formation and black hole growth are self-regulated in galaxies -- the ratio between black hole accretion rate and star formation rate remains nearly constant in a wide redshift span $z = 0-6$. These findings suggest that the observed correlations have different origins: the $\mbhsigma$ relation may be the result of virial equilibrium, while the $\mbhhost$ relation may the result of self-regulated star formation and black hole growth in galaxies.
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