Showing 3 results for Photometry
F N, Mt Mt,
Volume 11, Issue 3 (2-2011)
Abstract
In this paper, we analyze, near infra red images of the central region of the local group galaxy M33. These images were obtained in K band with the UFTI instrument, installed on the UKIRT telescope. This is a part of a bigger project started in 2003 with an aim to investigate RGB and AGB stars in M33. K band magnitude was obtained for 18509 stars by fitting appropriate PSF models to stellar profiles in the images. The final catalogue was obtained by calibrating instrumental magnitude to standard system. Cross correlation methods was manipulated to assign J-K color index to each star. A color magnitude diagram was plotted which represents population of RGB, AGB and Carbon stars in the core of M33 galaxy
Roya Karamian,
Volume 15, Issue 2 (2-2015)
Abstract
Saponins are secondary metabolites that are found in many plants and some animals. These compounds are high molecular weight glycosides, consisting of a sugar moiety linked to a triterpene or steroid aglycone. Many saponins have detergency properties and give stable foam in water. The genus Silene L. with more than 700 species is one of the largest genera of the family Caryophyllaceae mainly distributed in north hemisphere. Saponins are one of important secondary metabolites in members of the genus. Quantitative and qualitative study of the saponins in the aerial parts and roots of three Silene species, namely S. ginodioca, S. spergulifolia and S. swertiifolia were carried out by spectrophotometry and TLC methods. In this study, 5 fractions were obtained from each plant part and in both parts of three species, fraction 1 contain the highest amounts of saponins. On the other hands, root extracts have a high amount of saponins. In addition, thin layer chromatography (TLC) of the extracts evaluated some saponins spots with different Rf.
Volume 18, Issue 58 (8-2004)
Abstract
A spectrophotometric study concering the charge transfer interaction between 2,3-dichloro-5,6-dicyano-1,4-benzoquione (DDQ) and some benzophenoes has been carried out in chloroform at 25°C. Comparision of the spectra of the complexes of 1.2-dimethoxybenzene-DDQ and benzophenone-DDQ is indicative of two kinds of transitions: (i) n→π*, and (ii) π→π* respectively,). Formation constants of the resulting 1:1 molecular complexes were determined by using the Hildebrand method. The values of formation constants are in parallel with the charge density on the oxygen atoms of cabonyl groups. Also steric hindrance of substituents affects the stability of the resulting complexes. The shifts in stretching frequency of carbonyl groups of benzophenones, brought about upon complexation, further supports that donation takes place from oxygens of the carbonyl groups.
