A Modified Isotopic Exchange Rate Expression

1953 ◽  
Vol 21 (8) ◽  
pp. 1405-1406
Author(s):  
Rowland E. Johnson
Keyword(s):  
Exchange Rate ◽  
Isotopic Exchange ◽  
Rate Expression

Solubility, Diffusivity, and Isotopic Exchange Rate of Hydrogen Isotopes in Li-Pb

2008 ◽  
Vol 54 (1) ◽  
pp. 131-134 ◽  
Author(s):  
Y. Maeda ◽  
Y. Edao ◽  
S. Yamaguchi ◽  
S. Fukada
Keyword(s):  
Exchange Rate ◽  
Isotopic Exchange ◽  
Hydrogen Isotopes

Hydrogen isotopic exchange between D2 and H2O on alumina prepared by sputtering

1993 ◽  
Vol 71 (5) ◽  
pp. 663-669 ◽  
Author(s):  
Fumio Ioka ◽  
Tetsuo Sakka ◽  
Yukio Ogata ◽  
Matae Iwasaki
Keyword(s):  
Exchange Rate ◽  
Isotopic Exchange ◽  
Molecular Orbital Calculations ◽  
Base Pairs ◽  
Coordination Numbers ◽  
Rate Determining Step ◽  
Heat Treated ◽  
The Exchange Rate ◽  
Low Pressures ◽  
Oxygen Site

Hydrogen isotopic exchange between D2 and H2O has been investigated on alumina prepared by sputtering at 803 K and at low pressures. The alumina is amorphous, consisting of aluminum with coordination numbers four, five, and six in the ratio 1:2:1 as determined by NMR. A kinetic model is proposed on the basis of the pressure dependence of the exchange rate and the heats of adsorption at adsorbed sites, evaluating by molecular orbital calculations. The adsorbed sites are assumed to be Lewis acid–base pairs composed of a coordinatively unsaturated aluminum and the adjacent unsaturated oxygen site. The site relating to the rate-determining step contains threefold aluminum, which is formed by unsaturation of fourfold aluminum at the surface. As a consequence, the exchange rate depends on the amount of fourfold aluminum when the alumina is heat treated and changes its phase.

Isotope separation factor and isotopic exchange rate between hydrogen and deuterium of palladium

1995 ◽  
Vol 226 (3) ◽  
pp. 311-318 ◽  
Author(s):  
Satoshi Fukada ◽  
Katsuhiro Fuchinoue ◽  
Masabumi Nishikawa
Keyword(s):  
Exchange Rate ◽  
Separation Factor ◽  
Isotopic Exchange ◽  
Isotope Separation

Stable isotopic exchange rate constant between snow and liquid water

2009 ◽  
Vol 260 (1-2) ◽  
pp. 57-62 ◽  
Author(s):  
Jeonghoon Lee ◽  
Xiahong Feng ◽  
Eric S. Posmentier ◽  
Anthony M. Faiia ◽  
Susan Taylor
Keyword(s):  
Exchange Rate ◽  
Rate Constant ◽  
Liquid Water ◽  
Isotopic Exchange ◽  
Stable Isotopic ◽  
Exchange Rate Constant

Isotopic Exchange of Free Sulfur with Thiurams, Isothiocyanates and Dithiocarbamates

1961 ◽  
Vol 34 (2) ◽  
pp. 600-605
Author(s):  
L. S. Kuzina ◽  
E. N. Guryanova
Keyword(s):  
Activation Energy ◽  
Exchange Rate ◽  
Isotopic Exchange ◽  
Elementary Sulfur ◽  
Amino Group ◽  
Optimal Conditions ◽  
Phenyl Radicals ◽  
The Exchange Rate ◽  
Free Sulfur

Abstract 1. Studies were made concerning the exchangeability, with elementary radioactive sulfur, of sulfur atoms in 15 compounds including thiurams, dithiocarbamate and isothiocyanates. The number of exchangeable sulfur atoms in each material was established, as well as the optimal conditions for exchange, and for seven of the compounds the activation energy for the process was determined. The exchange rate of thiurams, with elementary sulfur, increases with the number of sulfur atoms in the polysulfide chain. In tetramethyl-thiuram tetrasulfide the two middle sulfur atoms are more readily exchanged, while the outer four sulfurs, bonded to carbon, are exchanged less rapidly but not sufficiently so to allow carrying out a separate exchange. 2. The velocity of exchange is significantly reduced in the thiuram disulfides when aliphatic radicals are replaced by phenyl radicals. A difference in the influence of amino-group radical variations was noted between the thiurams and the dithiocarbamates. The results of the isotopic exchange of sulfur in these materials have been considered from the viewpoint of their effectiveness as accelerators in the vulcanization of rubber.

scholarly journals SODIUM ISOTOPIC EXCHANGE RATE BETWEEN CRYSTALLINE ZIRCONIUM PHOSPHATE AND MOLTEN NaNO3

1975 ◽  
Vol 4 (12) ◽  
pp. 1293-1294
Author(s):  
Yasushi Inoue ◽  
Yoshimune Yamada
Keyword(s):  
Exchange Rate ◽  
Zirconium Phosphate ◽  
Isotopic Exchange
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