1,157 research outputs found

    Geometric curvatures of plane symmetry black hole

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    In this paper, we study the properties and thermodynamic stability of the plane symmetry black hole from the viewpoint of geometry. Weinhold metric and Ruppeiner metric are obtained, respectively. The Weinhold curvature gives phase transition points, which correspond to the first-order phase transition only at N=1, where NN is a parameter in the plane symmetry black hole. While the Ruppeiner one shows first-order phase transition points for arbitrary N≠1N\neq 1. Both of which give no any information about the second-order phase transition. Considering the Legendre invariant proposed by Quevedo et. al., we obtain a unified geometry metric, which gives a correctly the behavior of the thermodynamic interactions and phase transitions. The geometry is also found to be curved and the scalar curvature goes to negative infinity at the Davies' phase transition points when the logarithmic correction is included.Comment: 16 pages, 6 figure

    Revisiting Scalar Glueballs

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    It is commonly believed that the lowest-lying scalar glueball lies somewhere in the isosinglet scalar mesons f0(1370), f0(1500) and f0(1710) denoted generically by f0. In this work we consider lattice calculations and experimental data to infer the glue and qq components of f0. These include the calculations of the scalar glueball masses in quenched and unquenched lattice QCD, measurements of the radiative decays J/ψ→γf0, the ratio of f0 decays to ππ, KK and ηη, the ratio of J/ψ decays to f0(1710)ω and f0(1710)ϕ, the f0 contributions to Bs→J/ψπ+π−, and the near mass degeneracy of a0(1450) and K∗0(1430). All analyses suggest the prominent glueball nature of f0(1710) and the flavor octet structure of f0(1500)

    Method for Thermo-optic Analysis in a Star Sensor

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    An autonomous star sensor is a highly accurate attitude-measuring instrument used in spacecraft, and its performance is restricted by ambient temperature of the outer space. This paper puts forward an effective scheme to the thermooptic analysis using finite element analysis (FEA) and ray tracing in star sensor. Specific difficulties: (a) how to evaluate thermo-optic effect in star sensor, and (b) how to make FEA results useful in optical design mode have been resolved using the scheme. Based on this scheme, the errors of star sensor, which are caused by thermo-optic effects, can be investigated in any complicated temperature condition, and the required temperature scope for the thermal design can be achieved. For example, the errors of the star sensor were 0.0863" and 2.2933", when the temperature differences of the experimental optical system were 10 °C and 5 °C in axial and lateral, respectively.Defence Science Journal, 2010, 60(3), pp.276-281, DOI:http://dx.doi.org/10.14429/dsj.60.35

    Differential expression of ozone-induced gene during exposures to salt stress in Polygonum sibiricum Laxm leaves, stem and underground stem

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    The response of plants to environmental stresses is characterized by a number of physiological and biochemical changes that ultimately result from the selective increase or decrease in the biosynthesis of a large number of distinct proteins. In this report, we describe the characterization of an ozoneinduced transcript, PcOZI-1, which has been identified from Polygonum sibiricum Laxm by the rapid amplification of cDNA ends method (RACE). PcOZI-1 mRNA in untreated plants was detected at low levels in underground stem, leaves and at higher levels in stem. PcOZI-1 mRNA accumulation was transiently induced in stem 7-fold within the first 8 h of 3% NaHCO3 treatment. PcOZI-1 mRNA accumulation was also induced 22-fold in underground stem after 72 h. Sequence analysis of PcOZI-1 revealed that it encodes a 8.45 kDa basic protein that contains a putative signal peptide. Our results suggest that PcOZI-1 represents a novel stress-related protein that accumulates in response to the production of active oxygen species.Keywords: Polygonum sibiricum Laxm, PcOZI-1, rapid amplification of cDNA ends, gene expressionAfrican Journal of Biotechnology Vol. 9(33), pp. 5338-5342, 16 August, 201
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