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921.
922.
Polymer bound lactam enol phosphonates can be easily generated using simple phenol on polystyrene resin. These stable, storable compounds can be released in a diversity cleavage strategy, using Suzuki cross coupling conditions, to provide 2-arylenamides in moderate to good overall yields. 相似文献
923.
Ulmer TS Campbell ID Boyd J 《Journal of magnetic resonance (San Diego, Calif. : 1997)》2002,157(2):181-189
The effects of dissolved molecular oxygen upon amide proton ((1)H(N)) longitudinal and transverse relaxation rates and chemical shifts were studied for a small protein domain, the second type 2 module of fibronectin ((2)F2)-isotopically enriched to 99% (2)H, 98% (15)N. Longitudinal relaxation rate enhancements, R(O(2))((1)H(N)), of individual backbone (1)H(N) nuclei varied up to 14 fold between a degassed and oxygenated (1 bar) solution, indicating that the oxygen distribution within the protein is inhomogeneous. On average, smaller relaxation rate enhancements were observed for (1)H(N) nuclei associated with the core of the protein compared to (1)H(N) nuclei closer to the surface, suggesting restricted oxygen accessibility to some regions. In agreement with an O(2)-(1)H(N) hyperfine interaction in the extreme narrowing limit, the (1)H(N) transverse relaxation rates showed no significant change, up to an oxygen pressure of 9.5 bar (the maximum pressure used in this study). For most (1)H(N) resonances, small deltadelta(O(2))((1)H(N)) hyperfine chemical shifts could be detected between oxygen pressures of 1 bar and 9.5 bar. 相似文献
924.
P. Campbell A. Nieminen J. Billowes P. Dendooven K.T. Flanagan D.H. Forest Yu.P. Gangrsky J.A.R. Griffith J. Huikari A. Jokinen I.D. Moore R. Moore H.L. Thayer G. Tungate S.G. Zemlyanoi J. Äystö 《The European Physical Journal A - Hadrons and Nuclei》2002,15(1-2):45-48
A new RFQ ion-beam cooler and buncher, installed after the mass-separating magnet of the ion guide isotope separator, IGISOL,
JYFL, has dramatically increased the scope of on-line laser spectroscopy at this facility. The device, operated in a bunching
mode, has permitted new measurements on short-lived radionuclei in the Ti, Zr and Hf chains at a sensitivity two orders of
magnitude greater than that previously achieved. The device has also opened new prospects for laser-based nuclear spectroscopy
at the facility, particularly collinear resonance ionisation spectroscopy.
Received: 21 March 2002 / Accepted: 16 May 2002 / Published online: 31 October 2002
RID="a"
ID="a"e-mail: pc@mags.ph.man.ac.uk 相似文献
925.
N. G. Campbell 《Numerische Mathematik》1970,14(5):435-447
An application of stability analysis by the energy method is made to a practical problem of unsteady viscous flow solved numerically by Fromm. The practical stability criterion for the scheme is determined and a rigorous proof of convergence to a smooth solution is given. It is also shown how to construct an energy for any 3-level scalar difference equation. 相似文献
926.
Paul J Campbell 《Historia Mathematica》1978,5(1):77-89
The paper investigates the claim that “Zorn's Lemma” is not named after its first discoverer, by carefully tracing the origins of several related maximal principles and of the name “Zorn's Lemma.” Previously unpublished information supplied by Zorn is included. 相似文献
927.
P. Campbell 《International Journal of Theoretical Physics》1979,18(1):9-15
The use of projective geometry for the characterization of Lagrangian subspaces and maps among them is of particular interest for the symplectic manifold that is twistor space. We raise some conjectures on how these should be interpreted on the space-time manifold by making use of the structure of projective twistor space. 相似文献
928.
We discuss recent studies, using the quantum ensemble projector Monte Carlo (EPMC) method, of theoretical models of conducting
polymers. Our focus is on the consequences of incorporating direct electron-electron interactions into the “standard” electron-phonon
interaction models. Among the observables we examine one energetics of purely dimerized ground states, single solitons, soliton
pairs, averaged spin and charge distributions, and local correlation functions. 相似文献
929.
930.
Semicarbazide can be titrated quantitatively with potassium bromate in the presence of nickel(II), cobalt(III) and manganese(II) but copper(II) causes serious interference. The effects of copper ions on the reaction between potassium bromate and semicarbazide are investigated and the optimum conditions under which the reaction is quantitative are indicated. 相似文献