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931.
A numerical method for solving nonlinear integral equations of Volterra type is given. Starting procedures together with predictor and corrector algorithms are discussed in detail. 相似文献
932.
933.
A simple method for improving the input coupling in uncleaved waveguide photodetectors is demonstrated. A wedge-shaped recess is incorporated into the input facet to reduce reflection. Over a range of device sizes and wedge shapes, mean quantum efficiency was increased by 16% relative to flat, uncleaved input facets. 相似文献
934.
For five different Heisenberg spin glass systems, torque experiments were performed in applied magnetic fields up to 4 T. The Dzyaloshinski-Moriya random anisotropy strengths, the in-field torque onset temperatures, and the torque relaxation were measured. Critical exponents were estimated independently using a standard protocol. The data are strong evidence for a true spin glass ordered state which survives under high applied magnetic fields; they can be interpreted consistently in terms of a chiral ordering model with replica symmetry breaking as proposed by Kawamura and co-workers. 相似文献
935.
Stoian R Rosenfeld A Ashkenasi D Hertel IV Bulgakova NM Campbell EE 《Physical review letters》2002,88(9):097603
We report time-resolved studies using femtosecond laser pulses, accompanied by model calculations, that illuminate the difference in the dynamics of ultrashort pulsed laser ablation of different materials. Dielectrics are strongly charged at the surface on the femtosecond time scale and undergo an impulsive Coulomb explosion. This is not seen from metals and semiconductors where the surface charge is effectively quenched. 相似文献
936.
937.
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
938.
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
939.
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
940.
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