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891.
Biswajoy Brahmachari Patrick J. O’Donnell Utpal Sarkar 《Zeitschrift fur Physik C Particles and Fields》1997,74(1):171-178
An extension of the left-right symmetric model has been constructed which gives in a natural way the three lepton decay modes of the proton which have been suggested as an explanation for the atmospheric neutrino anomaly. We write down the potential which after minimization gives the proper choice of the Higgs spectrum. With this Higgs spectrum we then study the evolution of the gauge coupling constants and point out that for consistency one has to include effects of gravity. 相似文献
892.
Patrick Sharrock 《Polyhedron》1983,2(2):111-114
Glycine coordinated to cupric ions reacts in basic solution with a stoichiometric quantity of aldehydes to give β-hydroxyaminoacids. When the reaction contains a mixture of aldehydes, one of them being acetaldehyde, threonine is produced in the solution together with a variable amount of the bulkier substituted serine. An intermediate complex may be isolated which affords a larger proportion of substituted serines with predominance of the threo isomers. Acetaldehyde and benzaldehyde give a 66% yield of threo β-phenylserine. 相似文献
893.
The ionicity of oxide and β- and β″-Al2O3 crystals is identified via Lorentz–Lorenz molar refractivity. The investigation was extended to sodium gallates, the refractivity and average refractive index of which are estimated. 相似文献
894.
895.
896.
Fred R. Beyette Patrick J. Stanko Eric M. Hayes Rick D. Snyder Stewart A. Feld Pericles A. Mitkas Carl Wilmsen 《Optical Review》1996,3(6):A373-A375
The architecture of an optoelectronic recirculating sorter based on the hybrid integration of CMOS logic circuitry, silicon detector/receivers and vertical cavity surface emitting lasers is presented along with the demonstration of the system. 相似文献
897.
Slimane Mechahougui Harry Ramenah Jacques Harthong Patrick Meyrueis 《Optical Review》1996,3(2):96-100
We were mainly concerned here with multiple exposure gratings that allow interactions and coupling between gratings. We started the study of interactions and coupling with five gratings recorded in dichromated gelatin (DCG). Having determined experimentally the characteristic parameters of these five gratings, we used a method developed by Oxford University to synthesize the modulation profile. Entering these parameters of each grating into our computing programs (based on the alternative theory of diffraction in modulated media) and by varying the amplitude modulation, the latter was deduced by adjusting the numerical curve to the experimental one. We then extended the study to nine multiplexed gratings. This study allowed us to know the range of the amplitude modulation such that a certain number of angular multiplexing can be done in DCG. Several undesirable effects which we had experimentally observed appeared then during the reconstruction of any one of the multiplexed images, such as cross-talk effect. We noted the good concordance between experimental and theoretical results. We finally illustrated cross-talk effect in a diffractive memory where, if the amplitude modulation was first calculated, the number of multiplexing for an angular range could then be determined and the angular separation achieved to avoid cross-talk. 相似文献
898.
899.
The measurement of mechanical stresses in vapour quenched metal films can give additional structural information. Especially the near absence of stresses yields a sufficient condition for the formation of amorphous structures, since stress contributions due to the crystallite boundary mismatch are present in every micro crystalline film. From this point of view we find that Al films containing more than 25 at.% Ag grow in an amorphous phase whereas films with less than 25 at.% Ag are micro crystalline. The influence of other impurities, especially oxygen, is also investigated. Further evidence is presented for the high superconducting transition temperatures of Al films evaporated from Al2O3 crucibles, which films are micro crystalline, to be due to the presence of Al2O impurities in these films. 相似文献
900.
A gas chromatography-mass spectrometry assay is described for the simultaneous determination of threo-dl-methylphenidate and threo-dl-p-hydroxymethylphenidate in plasma and urine using selected ion monitoring of electron impact generated fragments of their pentafluoropropionyl derivatives. The use of recently available deuterated analogues as internal standards improves overall performance relative to previous methods. The practical limit of quantifiable detection of the assay is 0.5 ng/ml for both methylphenidate and p-hydroxymethylphenidate. p-Hydroxymethylphenidate appears to be a significant urinary metabolite of methylphenidate in rats but not in humans. 相似文献