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931.
932.
Albert A. Carr Mark W. Dudley Edward W. Huber John M. Kane Francis P. Miller 《Journal of heterocyclic chemistry》1987,24(1):239-241
A series of di-, tri-, tetra- and pentapeptide analogs of leucine-enkephalin have been prepared in which the initial tyrosinylglycine fragment has been replaced by the 5,6-dihydro-5,5-dimethyl-2-oxo-3-phenyl-1(2H)-pyrazineacetic acid moiety. 相似文献
933.
Given an embedding f: G →2 of a graph G in the two-dimensional lattice, let |f| be the maximum L1 distance between points f(x) and f(y) where xy is an edge of G. Let B2(G) be the minimum |f| over all embeddings f. It is shown that the determination of B2(G) for arbitrary G is NP-complete. Essentially the same proof can be used in showing the NP-completeness of minimizing |f| over all embeddings f: G → n of G into the n-dimensional integer lattice for any fixed n ≥ 2. 相似文献
934.
935.
Bryan L. Preppernau David A. Dolson Richard A. Gottscho Terry A. Miller 《Plasma Chemistry and Plasma Processing》1989,9(2):157-164
Ground-state atomic hydrogen produced in radio-frequency plasma discharges (20 KHz-5 MHz) has been detectedin situ using two-photon absorption laser-induced fluorescence (TALIF). Atomic ground-state concentration measurements have demonstrated excellent spatial resolution in the interelectrode gap of a planar discharge configuration with 10 nsec temporal resolution at all phases of the RF driving voltage waveform. Concentrations were measured in gas mixtures of helium and hydrogen down to 2×1013 H atoms/cm3. 相似文献
936.
937.
E D Verdonk S A Wickline J G Miller 《The Journal of the Acoustical Society of America》1992,92(6):3039-3050
Measurements of ultrasonic quasilongitudinal velocity were made in the muscle fiber plane of excised human myocardium. Multiple adjacent planes across the left ventricular wall were interrogated to assess the transmural dependence of velocity. For each measurement plane, data were obtained in 2-deg increments through the full 360 deg relative to the myofibers. An approximate 1.3% magnitude of anisotropy was observed with maximum velocity along the muscle fibers and minimum velocity perpendicular to the muscle fibers. The known transmural shift in myofiber orientation was evidenced in the anisotropy of velocity as angular shifts between plots obtained from adjacent transmural planes within the same specimen. Measured values of velocity and density were used to estimate the effective C33 and C11 elastic constants of a thin layer of normal myocardium. 相似文献
938.
939.
940.
R. Bambha D. C. Hutchings M. J. Snelling P. Likamwa A. Miller A. L. Moretti R. W. Wickman K. A. Stair T. E. Bird J. A. Cavaillès D. A. B. Miller 《Optical and Quantum Electronics》1993,25(12):S965-S971
Picosecond excite-probe studies are performed on a single quantum well waveguide modulator giving a direct measure of the escape of photogenerated carriers from a quantum well. Both the effects of exciton saturation and external field screening are observed in the transient transmission change. The results are consistent with the escape of carriers by thermionic emission. 相似文献