15 research outputs found
Magnitude And Color Transformations Between Sirius And 2Mass Photometric Systems
We provide magnitude and color transformations between two near-infrared photometric systems, 2MASS and SIRIUS, the latter currently implemented with the three-Channel SIRIUS camera on 1.4 m Infrared Survey Facility telescope at the South African Astronomical Observatory. The transformation equations are derived using a carefully selected sample of 32 770 stars in the. Large and Small Magellanic Clouds that have high quality observations available in both photometric systems. The derived transformations are valid in the color range -0.1 < (J - H)(SIRIUS) < 1.15, -0.05 < (H - K-s)(SIRIUS) < 0.7 and -0.1 < (J - K-s)(SIRIUS) < 1.7
Development of new highâperformance visible light photoinitiators based on carbazole scaffold and their applications in 3d printing and photocomposite synthesis
In this article, new compounds based on the carbazole scaffold (DMs = DM1 and DM2, constituted by a carbazole unit connected on positions 3 and 6 to a two 4,4âČâdimethoxydiphenylamine groups and differing by the substituent present on the nitrogen heteroatom of the carbazole core) were synthesized and proposed as highâperformance visible light photoinitiators/photosensitizers for both the freeâradical polymerization of methacrylates and the cationic polymerization of epoxides upon visible light exposure using LED@405ânm. Remarkably, DM2 leads to higher final conversions than DM1. In order to study the photophysical and photochemical properties of the carbazole derivatives, different parameters were taken into account such as the light absorption, the steadyâstate photolysis, and the fluorescence spectroscopy. Using different techniques such as fluorescence quenching, redox behavior, and cyclic voltammetry, we are able to discuss the photosensitization/photoinitiation reactions providing a full coherent picture of the involved chemical mechanisms. The photosensitization of the carbazole derivatives occurred predominantly via singlet excited states at the rate of the diffusion limit. Upon exposure to laser diode at 405ânm, DMs show high performance in initiating systems for 3D resins. Remarkably, DM2 can also be used in photocomposite synthesis using lightâemitting diode conveyor