The hard X-ray emission of active galactic nuclei (AGN) is believed to originate from the hot coronae above the cold accretion discs. The hard X-ray spectral index is found to be correlated with the Eddington ratio Lbol/LEdd, and the hard X-ray bolometric correction factor Lbol/LX,2−10keV increases with the Eddington ratio. The Compton reflection is also found to be correlated with the hard X-r...

For p ∈ (0, 1), let Q p be the subspace consisting of Möbius bounded functions in the Dirichlet-type space. Based on the study of the multipliers in Q p , we establish the corona theorem for Q p .

This paper deals with the numerical modelling of corona discharges induced by electrohydrodynamic actuators. A specific numerical method is proposed and discussed to compute the multiscale nature observed in the modelling of corona discharges. The idea consists in a domain decomposition of the computational domain where each subdomain is described with a specific modelling well adapted to the p...

let $g=(v,e)$ be a‎ ‎simple graph of order $n$ and size $m$‎. ‎an $r$-matching of $g$ is ‎a set of $r$ edges of $g$ which no two of them have common vertex‎. ‎the hosoya index $z(g)$ of a graph $g$ is defined as the total‎ ‎number of its matchings‎. ‎an independent set of $g$ is a set of‎ ‎vertices where no two vertices are adjacent‎. ‎the ‎merrifield-simmons index of $g$ is defined as the tota...

Temperature inversions occur in nature, e.g., in the solar corona and in interstellar molecular clouds: Somewhat counterintuitively, denser parts of the system are colder than dilute ones. We propose a simple and appealing way to spontaneously generate temperature inversions in systems with long-range interactions, by preparing them in inhomogeneous thermal equilibrium states and then applying ...

It is clear that the solar corona is being heated and that coronal magnetic fields undergo reconnection all the time. Here we attempt to show that these two facts are related--i.e. coronal reconnection generates heat. This attempt must address the fact that topological change of field lines does not automatically generate heat. We present one case of flux emergence where we have measured the ra...

Recently, a new universal HPLC detection technology has been developed based on charged aerosol detection that has led to the development of a universal HPLC detector, the Corona CAD. To further understand the capabilities of charged aerosol detection and the use of the technology in an HPLC detector, the Corona CAD was tested for its sensitivity, dynamic range, response from compounds of diffe...

Cool stars such as our Sun are surrounded by a million degree hot outer atmosphere, the corona. For more than 60 years, the physical nature of the processes heating the corona to temperatures well in excess of those on the stellar surface have remained puzzling. Recent progress in observational techniques and numerical modeling now opens a new window to approach this problem. We present the fir...

Measurements of the temperature and density structure of the solar corona provide critical constraints on theories of coronal heating. Unfortunately, the complexity of the solar atmosphere, observational uncertainties, and the limitations of current atomic calculations, particularly those for Fe, all conspire to make this task very difficult. A critical assessment of plasma diagnostics in the c...