Critical magnetic field in holographic superconductor in Gauss-Bonnet gravity with Born-Infeld electrodynamics

In the paper using matching method in the probe limit, we investigate some properties of holographic superconductor in Gauss-Bonnet gravity with Born-Infeld electrodynamics . We discuss the effects of the Gauss-Bonnet coupling \a and Born-Infeld parameter $b$ on the critical temperature and condensate. We find that both of \a and $b$ make the critical temperature decrease, which implies the condensate harder to form. Moreover we study the magnetic effect on holographic superconductor and obtain that the ratio between the critical magnetic field and the square of the critical temperature increases from zero as the temperature is lowered below the critical value $T_c$, which agrees well with the former results. We also find the critical magnetic field is indeed affected by Gauss-Bonnet coupling, but not by Born-Infeld parameter.Comment: 13 pages, 5 figure

Automatic Recognition of Sunspots in HSOS Full-Disk Solar Images

A procedure is introduced to recognise sunspots automatically in solar full-disk photosphere images obtained from Huairou Solar Observing Station, National Astronomical Observatories of China. The images are first pre-processed through Gaussian algorithm. Sunspots are then recognised by the morphological Bot-hat operation and Otsu threshold. Wrong selection of sunspots is eliminated by a criterion of sunspot properties. Besides, in order to calculate the sunspots areas and the solar centre, the solar limb is extracted by a procedure using morphological closing and erosion operations and setting an adaptive threshold. Results of sunspot recognition reveal that the number of the sunspots detected by our procedure has a quite good agreement with the manual method. The sunspot recognition rate is 95% and error rate is 1.2%. The sunspot areas calculated by our method have high correlation (95%) with the area data from USAF/NOAA.Comment: 9 pages, 6 figures, 2 tables, accepted for publication in PAS

Integrating Existing Software Toolkits into VO System

Virtual Observatory (VO) is a collection of interoperating data archives and software tools. Taking advantages of the latest information technologies, it aims to provide a data-intensively online research environment for astronomers all around the world. A large number of high-qualified astronomical software packages and libraries are powerful and easy of use, and have been widely used by astronomers for many years. Integrating those toolkits into the VO system is a necessary and important task for the VO developers. VO architecture greatly depends on Grid and Web services, consequently the general VO integration route is "Java Ready - Grid Ready - VO Ready". In the paper, we discuss the importance of VO integration for existing toolkits and discuss the possible solutions. We introduce two efforts in the field from China-VO project, "gImageMagick" and " Galactic abundance gradients statistical research under grid environment". We also discuss what additional work should be done to convert Grid service to VO service.Comment: 9 pages, 3 figures, will be published in SPIE 2004 conference proceeding