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1.
Muonium in liquid SiCl has been observed for the first time at low temperature (−65°C) The observed polarization of muonium
is as much as 25% of the total spin polarization and shows a fast relaxation rate. 相似文献
2.
Richard A. Reid Walter A. StarkJr 《The Journal of the Operational Research Society》1988,39(2):135-139
Individual/group replacement models were used to identify the minimum-cost policy for replacing protective gloves that are utilized in product fabrication at a nuclear processing facility. Since historical data on glove longevity were not available to determine the failure-rate distribution, the classical replacement model for items that fail was modified to consider glove life as a normally distributed variable. Moreover, the absence of replacement-cost required that the classical model be transformed to incorporate the ratio of single to unit-group replacement cost. Sensitivity analysis on these two input parameter values provided guidance for the development of an appropriate replacement policy. 相似文献
3.
R. R. Mendel Kimball A. Milton James H. Reid Mark A. Samuel 《Zeitschrift fur Physik C Particles and Fields》1986,32(4):517-520
Several methods to determine (or set an upper bound on) the mass of the tau neutrino are described. The decay spectrum of \(\tau \to e\bar \nu _e \nu _\tau \) near the high center-of-mass electron-energy end is particularly sensitive to the tau-neutrino mass. It is shown that an upper bound of 20 MeV or lower may be feasible. In addition, improved limits on the mass and mixing angle of a heavy component of the tau-neutrino may be readily obtained. We also discuss the purely leptonic decays of theD andF mesons, and show how measurements of the ratiosB(D→τντ/B(D→μνμ,B(F→τντ/B(D→μνμ can be sensitive to tau-neutrino masses of 30 MeV or greater. 相似文献
4.
J. Reid Shelton D. E. Agostini J. B. Lando 《Journal of polymer science. Part A, Polymer chemistry》1971,9(10):2789-2799
Synthesis of the naturally occurring polyester, D -poly-β-hydroxybutyrate (PHB) was accomplished by using an optically active monomer. Polymerization of D -(+)-β-butyrolactone (β-BL) of 73% optical purity with a catalyst system of Et3Al–H2O produced a polymer with a similar optical activity and essentially identical to the natural polymer as isolated from bacterial cells. This paper describes the synthesis and characterization of this optically active polyester along with a suggested mechanism to account for the observed stereospecific polymerization of β-BL with this catalyst system. 相似文献
5.
The silicate compounds Sc2Si2O7 and In2Si2O7 have been converted from thortveitite type to pyrochlore type at 1000°C, 120 kbar, with resulting cell constants of 9.287(3) and 9.413(3) Å, respectively. Invariant reflection intensities in the X-ray powder diffraction patterns allowed precise absorption corrections to be made, and refinement of thermal parameters and of the single structural parameter x gave values of 0.4313(21) and 0.4272(15), respectively. The corresponding six-coordinate SiO distances were 1.761(7) and 1.800(5) Å, and the average eight-coordinate distances for ScO8 and InO8 were 2.267 and 2.275 Å. Values of structure-refined bond lengths for compounds containing six-coordinate silicon are surveyed, and overall weighted average octahedral distances of 1.782(14) Å for SiO and 2.520(18) Å for OO are derived. Pyrochlore phases were not produced from rare-earth disilicate or monosilicate phases subjected to the same reaction conditions as the Sc and In compounds. 相似文献
6.
Martina Schwager Emil Roduner Ivan D. Reid Paul W. Percival Jean-Claude Brodovitch Stanislaw Wlodek Robert F. Marzke 《Hyperfine Interactions》1994,87(1):859-864
SR spectra of the ethyl radical adsorbed on porous silica were observed in transverse and in longitudinal magnetic fields in the temperature range 190–298 K. The line widths reflect the dynamic partial averaging of the hyperfine anisotropy due to reorientation and surface diffusion. 相似文献
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10.
O'Hair RA Androutsopoulos NK Reid GE 《Rapid communications in mass spectrometry : RCM》2000,14(18):1707-1716
The proposal that protonated peptides react with NH(3) in the gas phase via transacylation reactions (Tabet et al., Spectros. Int. J. 5: 253 1987) has been investigated by studying the reactions of the fixed charge derivatives [RC(O)NMe(2)CH(2)CO(2)H](+) (R=Me and Ph) with pyridine and triethylamine and the reactions of protonated glycine oligomers and leucine enkenphalin with butylamine. Under the near thermal conditions of the quadrupole ion trap, both the fixed charge derivatives as well as the protonated peptides react with the amines via either proton transfer or proton bound dimer formation. Collision induced dissociation of protonated peptides in the presence of butylamine yields b(n) and y(n) sequence ions as well as [b(n) + BuNH(2)](+) and [y(n) + BuNH(2)](+) ions. MS(3) experiments reveal that a major route to these [b(n) + BuNH(2)](+) and [y(n) + BuNH(2)](+) ions involves ion-molecule reactions between the b(n) and y(n) sequence ions and butylamine. MS(4) experiments, carried out to determine the nature of the [b(n) + BuNH(2)](+) ions, reveal that they correspond to a mixture of hydrogen bonded (i.e. proton bound dimer) and covalent amide bond structures. 相似文献