scholarly journals Study of Isomer Ratio in (\(n,2n\)) and (\(\gamma , n\)) Reactions on the \(^{140}\)Ce Nucleus

2021 ◽  
Vol 14 (4) ◽  
pp. 827
Author(s):  
S.R. Palvanov ◽  
F.R. Egamova ◽  
M.I. Mamayusupova ◽  
S.R. Egamov
Keyword(s):  
Isomer Ratio

scholarly journals Mechanistic Study on the Reaction of pinB-BMes2 with Alkynes Based on Experimental Investigation and DFT Calculations: Gradual Change of Mechanism Depending on the Substituent

2021 ◽  
Author(s):  
Linlin Wu ◽  
Chiemi Kojima ◽  
Ka Ho Lee ◽  
Shogo Morisako ◽  
Zhenyang Lin ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Transition Metal ◽  
Dft Calculations ◽  
Kinetic Analysis ◽  
Reaction Rate ◽  
Mechanistic Study ◽  
Isomer Ratio ◽  
Gradual Change ◽  
Isomeric Mixture ◽  
Metal Free

Transition-metal free direct and base-catalyzed 1,2-diborations of arylacetylenes using pinB-BMes2 provided syn/anti-isomeric mixture of diborylalkenes. The kinetic analysis showed that the reaction rate and isomer ratio were affected by reaction...

FORMATION OF DIASTEREOISOMERIC ORTHOACETATES OF D-MANNOSE: N.M.R. SPECTRAL EVIDENCE

1963 ◽  
Vol 41 (2) ◽  
pp. 399-406 ◽  
Author(s):  
A. S. Perlin
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Acid Hydrolysis ◽  
Chemical Shifts ◽  
Isomer Ratio ◽  
Methyl Group ◽  
Major Isomer ◽  
Spectral Evidence ◽  
Ratio Data ◽  
Nuclear Magnetic

Diastereoisomeric 1,2-orthoacetates of D-mannose are formed under conditions of the Königs–Knorr synthesis. This is shown by the isolation of two crystalline isomers of β-D-mannose 1,2-(benzyl orthoacetate), and also by examination of the nuclear magnetic resonance (n.m.r.) spectra of several D-mannose orthoacetates. The diastereoisomers show notable differences in respective chemical shifts for the C-methyl and other protons and these variations, together with isomer-ratio data, suggest that the major isomer of a given pair possesses the configuration in which the C-methyl group is endo- and the OR group is exo-. On acid hydrolysis the orthoacetates yield mainly 2-O-acetyl-D-mannose, the structure of which is confirmed by n.m.r. spectral evidence.

Measurements of natCd(γ, x) reaction cross-sections and isomer ratio of 115m,gCd with the bremsstrahlung end-point energies of 50- and 60-MeV

2021 ◽  
Author(s):  
Muhamad Nadeem ◽  
Md. Shakilur Rahman ◽  
Muhamad Shahid ◽  
Guinyun Kim ◽  
H. Naik ◽  
...  
Keyword(s):  
Cross Sections ◽  
Reaction Cross ◽  
Isomer Ratio ◽  
End Point ◽  
Reaction Cross Sections

scholarly journals Rapid hydrolysis of tertiary isoprene nitrate efficiently removes NOx from the atmosphere

2020 ◽  
Vol 117 (52) ◽  
pp. 33011-33016
Author(s):  
Krystal T. Vasquez ◽  
John D. Crounse ◽  
Benjamin C. Schulze ◽  
Kelvin H. Bates ◽  
Alexander P. Teng ◽  
...  
Keyword(s):  
Transport Model ◽  
Deuterium Oxide ◽  
Ambient Air ◽  
Water Volume ◽  
Isomer Ratio ◽  
Atmospheric Measurements ◽  
Laboratory Findings ◽  
Loss Process ◽  
Isomer Distribution ◽  
Hydrolysis Of

The formation of a suite of isoprene-derived hydroxy nitrate (IHN) isomers during the OH-initiated oxidation of isoprene affects both the concentration and distribution of nitrogen oxide free radicals (NOx). Experiments performed in an atmospheric simulation chamber suggest that the lifetime of the most abundant isomer, 1,2-IHN, is shortened significantly by a water-mediated process (leading to nitric acid formation), while the lifetime of a similar isomer, 4,3-IHN, is not. Consistent with these chamber studies, NMR kinetic experiments constrain the 1,2-IHN hydrolysis lifetime to less than 10 s in deuterium oxide (D2O) at 298 K, whereas the 4,3-IHN isomer has been observed to hydrolyze much less efficiently. These laboratory findings are used to interpret observations of the IHN isomer distribution in ambient air. The IHN isomer ratio (1,2-IHN to 4,3-IHN) in a high NOx environment decreases rapidly in the afternoon, which is not explained using known gas-phase chemistry. When simulated with an observationally constrained model, we find that an additional loss process for the 1,2-IHN isomer with a time constant of about 6 h best explains our atmospheric measurements. Using estimates for 1,2-IHN Henry’s law constant and atmospheric liquid water volume, we show that condensed-phase hydrolysis of 1,2-IHN can account for this loss process. Simulations from a global chemistry transport model show that the hydrolysis of 1,2-IHN accounts for a substantial fraction of NOx lost (and HNO3 produced), resulting in large impacts on oxidant formation, especially over forested regions.

Isomeric yield ratios of 133Xe in fission of 232Th, 233U, 235U, and 238U with protons of energies 20–85 MeV

1968 ◽  
Vol 46 (10) ◽  
pp. 1763-1772 ◽  
Author(s):  
J. H. Forster. ◽  
L. Yaffe
Keyword(s):  
Projectile Energy ◽  
Isomer Ratio ◽  
Spin Pair ◽  
Isomeric Yield ◽  
Input Parameters ◽  
Weakly Dependent

The ratio of 133Xe isomers produced in the fission of 232Th, 233U, 235U, and 238U by protons ranging in energy from 20–85 MeV was measured. The Hafner, Huizenga, and Vandenbosch formalism was applied with different sets of input parameters to establish their effect on the relation between initial fragment spin and isomer ratio for three spin-pair classes of isomers. The isomer ratio was found to be independent of the spin and type of fissioning target and only weakly dependent on projectile energy.

Retinal isomer ratio in dark-adapted purple membrane and bacteriorhodopsin monomers

Biochemistry ◽  
1989 ◽  
Vol 28 (2) ◽  
pp. 829-834 ◽  
Author(s):  
P. Scherrer ◽  
M. K. Mathew ◽  
W. Sperling ◽  
Walther Stoeckenius
Keyword(s):  
Purple Membrane ◽  
Isomer Ratio

Analysis of d-Phenothrin and Its Optical Isomers in Technical Preparations and Formulations

1985 ◽  
Vol 68 (5) ◽  
pp. 911-916 ◽  
Author(s):  
Tadashi Doi ◽  
Shigeyuki Sakaue ◽  
Masao Horiba
Keyword(s):  
Gas Chromatography ◽  
Liquid Chromatography ◽  
Optical Isomers ◽  
Isomer Ratio ◽  
Trans Isomers ◽  
Internal Standards ◽  
Cis And Trans Isomers ◽  
Alkaline Conditions ◽  
Cis And Trans

Abstract The content of d-phenothrin in technical preparations was determined by gas chromatography (GC) on a column of 2% PEG-20M or 2% DEGS, using suitable internal standards. The cis- and trans-isomers were separated from each other and determined on a 2% QF-1 column. The 4 optical isomers of rf-phenothrin were hydrolyzed in alkaline conditions to liberate chrysanthemic acid, which was derivatized to diastereoisomeric </-2-octyl esters, and the isomer ratio was determined by GC. The 4 optical isomers were also separated from one another directly on a chiral Sumipax OA-2000 column by liquid chromatography (LC). Also, after the propellant gas in an aerosol formulation was released, and the remaining liquid was analyzed using the same GC conditions as those used for technical preparations

Kinetics and equilibrium of the olefin-promoted interconversion of n-butyryl- and isobutyrylcobalt tetracarbonyl. The aldehyde isomer ratio in the cobalt-catalyzed olefin hydroformylation

1992 ◽  
Vol 11 (4) ◽  
pp. 1576-1579 ◽  
Author(s):  
Mihail S. Borovikov ◽  
Istvan Kovacs ◽  
Ferenc Ungvary ◽  
Attila Sisak ◽  
Laszlo Marko
Keyword(s):  
Isomer Ratio ◽  
Olefin Hydroformylation
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