4,247 research outputs found
Remarks on an operator Wielandt inequality
Let be a positive operator on a Hilbert space with and and are two
isometries on such that . For every 2-positive linear
map , define
We consider several upper bounds for
. These bounds complement a recent result on
operator Wielandt inequality.Comment: 6page
Properties of the narrow line Seyfert 1 galaxies revisited
There is growing evidence to suggest that the black hole mass has been
previously underestimated with the H line width for certain active
galactic nuclei (AGN). With the assumption of the flatter rather than isotropic
velocity distribution of gases in the broad-line region of AGN, we investigated
the properties of narrow line Seyfert 1 (NLS1) galaxies, like the black hole
mass and the Eddington ratio, and compared with broad line Seyfert 1 (BLS1)
galaxies. Since gamma-rays detected in a few NLS1s which favor a smaller
viewing angle in NLS1s than BLS1s, with the projection effect we estimated the
relative black hole mass and Eddington ratio for NLS1s and BLS1s. The result
implies that the NLS1s and BLS1s have similar black hole masses and Eddington
ratios, peaked at a larger black hole mass and lower Eddington ratio for the
NLS1s than thought before. Furthermore, with applying the correction factor 6
of average black hole mass as derived from the modelling of both optical and UV
data in radio-loud NLS1s by Calderone et al., to the Xu et al. sample, we find
that the NLS1s and BLS1s also show similar black hole masses and Eddington
ratios, peaked at and 0.12 (Eddington ratio) for the
NLS1s. The relation due to the enhanced black hole masses of
NLS1s is discussed. In addition, there seems to show a linear correlation
between jet power and disk luminosity for the flat spectrum radio-loud NLS1
sample, which implies an accretion dominated rather than black hole spin
dominated jet.Comment: 9 pages, 6 figures, accepted for publication in International Journal
of Astronomy and Astrophysic
A new electrochemical method for the determination of chondroitin sulfate based on its supramolecular interaction with cupferron-lead(II) complex
In this paper, the interaction of cupferron (Cup) and lead (II) complex
[Cup-Pb (II)] with chondroitin sulfate (CS) was investigated by linear sweep
voltammetric method. In the selected medium of pH 5.5 (acetic acid-hexamine
buffer solution), Cup can interact with Pb (II) to form a stable complex of
[Cup-Pb(II)], which has a sensitive second order derivative polarographic
reductive peak at -0.64V (vs.SCE). After the addition of CS into Cup-Pb (II)
complex solution, the reductive peak current decreased without any shift of
the peak potential and no new peak appeared, which indicated that an
unelectroactive supramolecular complex of CS with [Cup-Pb(II)] was formed.
The binding reaction conditions were carefully investigated. Under the
optimal conditions, the interaction mechanism was discussed. The decrease of
reductive peak current was directly proportional to the CS concentration,
thus a new quantitative determination method for CS was established with the
linear regression equation as ΔIp″(nA)=36.97 C/mg L-1+12.45 (n=10, γ=0.995).
The effects of other substances on the determination were carefully
investigated and three synthetic samples were determined with satisfactory
results. The binding constant (βs) and the binding number (m) of CS with
[Cup-Pb(II)] complex were calculated from the voltammetric data with the
results as βs=1.89×1010 and m≈2.5
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