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F Gonnet F Kocher JC Blais G Bolbach JC Tabet JC Chottard 《Canadian Metallurgical Quarterly》1996,31(7):802-809
The kinetics of the reaction between the octanucleotide d(TTGGCCAA) in the single-stranded form in pure water and the platinum complex [Pt(NH3)3(H2O)]2+ was investigated by electrospray ionization and matrix-assisted laser desorption/ionization (MALDI) mass spectrometries coupled with enzymatic degradation of the adducts. These methods led to the determination of specific rate constants of platination. The global rate constant characteristic of the formation of adducts on each 5'- or 3'-guanine were measured by electrospray ionization analysis. The ratios between the 5'- and 3'-adducts were determined from enzymatic degradation of the final reaction mixture and MALDI analysis. The platination in water is approximately eight times faster than in 0.1 M NaClO4. The selectivity of platination is a factor of 2 in favor of the 5'-guanine, and similar to that observed for the reaction between d(CTGGCTCA) and [Pt(NH3)3(H2O)]2+ in 0.1 M NaClO4. 相似文献
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R Meier TC Owen HE Matthews DC Jewitt D Bockelée-Morvan N Biver J Crovisier D Gautier 《Canadian Metallurgical Quarterly》1998,279(5352):842-844
Deuterated water (HDO) was detected in comet C/1995 O1 (Hale-Bopp) with the use of the James Clerk Maxwell Telescope on Mauna Kea, Hawaii. The inferred D/H ratio in Hale-Bopp's water is (3.3 +/- 0.8) x 10(-4). This result is consistent with in situ measurements of comet P/Halley and the value found in C/1996 B2 (Hyakutake). This D/H ratio, higher than that in terrestrial water and more than 10 times the value for protosolar H2, implies that comets cannot be the only source for the oceans on Earth. 相似文献
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Yoshinao Kobayashi Kazuki Morita Nobuo Sano 《Metallurgical and Materials Transactions B》1995,26(3):557-561
The standard Gibbs energy of formation of 3BaO · Cr2O3 has been measured by a chemical equilibrium technique and is expressed as follows: 3BaO (s) + 2Cr (s) + 3/2 O2 (g) = 3BaO · Cr2O3 (s) ΔGo = -1,260,000 (±3000) + 282 (±24)r(J/mol)
The activity coefficient of chromium in copper, which was needed for the foregoing measurement, may be expressed by the following
equation: 5790 log γ
Cr
o =5790/T-2.10
The value of standard Gibbs energy at 1573 K was found to be close to that of reaction of formation of CaO · Cr2O3 expressed in the similar form. The BaO saturated BaF2 flux is shown to be far more promising in the oxidative dephosphorization of chromium-containing hot metal in comparison
with the CaO-SiO2-CaF2 flux doubly saturated with CaO and 3CaO-Cr2O3. 相似文献