487 research outputs found
The reaction of forsterite with hydrogen-its apparent and real temperature dependences
We have studied experimentally the reaction rate between solid forsterite and hydrogen gas, one of the most fundamental reactions in the solar nebula. It was found that the rate-controlling gas species was atomic hydrogen rather than molecular hydrogen, from the linear dependence of the reaction rate on P_H. The temperature dependence of the reaction rate was determined both under constant P_ and under constant P_H conditions. The former, "apparent" activation energy of the reaction was estimated to be 86.5±4.8 (2σ)kcal/mol. The latter, "real" activation energy was estimated to be 32.6±4.8 (2σ)kcal/mol. From this, a general formula that gives the true reaction rate of forsterite with hydrogen was obtained : log_(J_F/g cm^s^)=-32.6(±4.8)×10^3/2.303 RT+log_(P_H/atm)+4.00(±0.07)
PALLADIUM-CATALYZED AMINATION OF 2-CHLORO-1-AZAAZULENE WITH 2-AMINOPYRIDINE
Palladium-catalyzed amination of 2-chloro-1-azaazulene with 2-aminopyridine was studied under various conditions in order to obtain N-(1-azaazulen-2-yl)-N-(2-pyridyl)amine (4) and N,N-bis(1-azaazillen-2-yl)-N-(2-pyridyl)amine (5) as a multidentate ligand. Results of the reaction and physical and chemical properties of 4 and 5 are described.ArticleHETEROCYCLES. 83(3):547-554 (2011)journal articl
Cryogenic measurement of the optical absorption coefficient in sapphire crystals at 1.064(micro)m for the Large-scale Cryogenic Gravitational wave Telescope
We have applied laser calorimetry to the measurement of optical absorption in
mono-crystalline sapphire at cryogenic temperatures. Sapphire is a promising
candidate for the mirror substrates of the Large-scale Cryogenic Gravitational
wave Telescope. The optical absorption coefficients of different sapphire
samples at a wavelength of 1.064(micro)m at 5K were found to average 90ppm/cm.Comment: 8 pages, accepted to Phys. Lett.
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