Results 151 to 160 of about 1,071,828 (189)

Nitrogen‐15 Variations in Fertilizer Nitrogen

Journal of Environmental Quality, 1974
AbstractNitrogen‐15 concentrations of some commonly used nitrogen fertilizers are measured. Ammonium‐nitrogen has lower and nitrate‐nitrogen has higher 15N concentrations than atmospheric nitrogen. The mean difference between both is about 4 δ 15N.
H. D. Freyer, A. I. M. Aly
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Nitrogen-15 spin relaxation in oximes

Journal of Magnetic Resonance (1969), 1979
Abstract 15N NMR spectral parameters are reported for several aldoximes and ketoximes. Syn and anti isomers are resolved and observed for acetaldoxime and propanaldoxime. 15N spin-lattice relaxation times (T1's) for the non-protonated nitrogens in these small molecules are not excessively long (∼25 to 50 sec).
George C Levy, Allen Godwin, Clive E Holloway   +2 more
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Nitrogen‐15 in apple nutrition investigations

Journal of the Science of Food and Agriculture, 1975
AbstractYoung apple trees growing in pots of soil were treated with N‐15 labelled potassium nitrate or urea at different times of year. Over periods of several months whole trees were harvested and divided into their component tissues for total N and N‐15 analyses; the latter were carried out using an emission spectrometer.
Dennis G. Hill‐Cottingham, Charles P. Lloyd‐Jones   +1 more
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ChemInform Abstract: NITROGEN‐15 CHEMICAL SHIFTS AND CARBON‐13‐NITROGEN‐15 COUPLING CONSTANTS OF CYANIDE COMPLEXES

Chemischer Informationsdienst, 1982
AbstractUntersuchungen an den oktaedrischcn Hexacyanokomplexen [M1(CN)6]4‐(M1: Fe, Ru.
M. SANO, Y. YOSHIKAWA, H. YAMATERA
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Nitrogen-15 nuclear magnetic resonance studies of porphyrins

Journal of the American Chemical Society, 1977
The ^(15)N NMR spectra of meso-tetraphenylporphyrin, its dication, and zinc tetraphenylporphyrin have been investigated both at the natural-abundance level and with isotopic enrichment. The resonances of tetraphenylporphyrin at ambient temperatures are broadened by chemical exchange of the central hydrogen atoms.
Gust, Devens, Roberts, John D.
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Nitrogen‐15 NMR spectroscopy: Nitrogen‐15 chemical shifts of 1,2‐diaminobenzenes and 1,8‐diaminonaphthalenes

Magnetic Resonance in Chemistry, 1991
AbstractNitrogen‐15 chemical shifts of 1,2‐diaminobenzenes, 1,8‐diaminonaphthalenes and their monoprotonated species are reported.
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High Resolution Optical Nitrogen-15 Analysis

Applied Spectroscopy, 1974
In 1938, presumably for the first time, emission spectroscopy was used for determining the abundance of the heavy isotope in natural nitrogen. Since then optical 15N analysis, including sample preparation, has been developed and refined.
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Dynamic nuclear polarization of nitrogen-15 in benzamide

Solid State Nuclear Magnetic Resonance, 1997
A 15N dynamic nuclear polarization (DNP) experiment is reported in which a 15N DNP enhancement factor of approximately 2.6 x 10(2) is obtained on free radical doped samples of 99% 15N labeled benzamide. The free radicals BDPA (1:1 complex of alpha, gamma-bisdiphenylene-beta-phenylallyl with benzene) and DPPH (2,2-Di(4-tert-octylphenyl)-1-picrylhydrazyl)
J Z, Hu, J, Zhou, B, Yang, L, Li, J, Qiu, C, Ye, M S, Solum, R A, Wind, R J, Pugmire, D M, Grant   +9 more
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The influence of nitrogen-15 proton-driven spin diffusion on the measurement of nitrogen-15 longitudinal relaxation times

Journal of Magnetic Resonance, 2007
The effect of nitrogen-15 proton-driven spin diffusion on quantitative (15)N T(1) measurements in solid proteins is investigated, and the impact on the measurement of dynamic parameters is assessed. A simple model of exchange between neighboring nitrogens is used to reproduce the evolution of (15)N spin systems whose longitudinal relaxation rates and ...
Giraud, N., Blackledge, M., Bockmann, A., Emsley, L.   +3 more
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Nitrogen-15 magnetic resonance spectroscopy. Natural-abundance nitrogen-15 spectra of some 2-amino-2-deoxy-D-hexose derivatives

The Journal of Organic Chemistry, 1977
The nitrogen-15 nuclear magnetic resonance spectra of some 2-amino-2-deoxj D-hexose drochlorides and 2-acetamido-2-deoxy-D-hexoses and N-benzoyl-D-glucosamine are reported. The differences in chemical shifts for the various hexopyranose structures are discussed in terms of steric, stereoelectronic, and hydrogen-bonding effects.
Botto, Robert E., Roberts, John D.
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