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21.
We present a model of leptogenesis that preserves lepton number. The model maintains the important feature of more traditional leptogenesis scenarios: The decaying particles that provide the CP violation necessary for baryogenesis also provide the explanation for the smallness of the neutrino Yukawa couplings. This model clearly demonstrates that, contrary to conventional wisdom, neutrinos need not be Majorana in nature in order to help explain the baryon asymmetry of the universe. 相似文献
22.
Let L be a linear map on the space of n×n matrices over a field. We determine the structure of the maps L that preserve commutativity. We also determine the structure of all linear maps on complex matrices that preserve the higher numerical range. The main tool is the Fundamental Theorem of Projective Geometry. 相似文献
23.
T. B. Pierce P. F. Peck D. R. A. Cuff 《Journal of Radioanalytical and Nuclear Chemistry》1970,4(2):305-309
Aluminium, iron and silicon have been determined in a number of binary and ternary oxide mixtures at levels>1% by measuring
the gamma-lines emitted as a result of inelastic neutron scattering. 相似文献
24.
Several pertinent parameters are frequently overlooked in specifying metal mirrors for high energy laser systems. This report outlines the importance of those parameters and describes both the typical and the state-of-the-art characteristics presently available. 相似文献
25.
26.
The application of the Rayleigh-Ritz method for approximating the eigenvalues and eigenfunctions of linear eigenvalue problems in several dimensions is investigated. The object is to improve upon known error estimates for the approximate eigenfunctions. Results for the Galerkin approximation of the eigenfunctions are developed under varying assumptions on the boundary conditions and domain of definition of the eigenvalue problem. These results, coupled with a previous result relating Galerkin and Rayleigh-Ritz approximation of the eigenfunctions, are then used to obtain improved error estimates for the approximate eigenfunctions in theL
2 and uniform norms.This research was supported in part by AEC Grant (11-1)-2075. 相似文献
27.
[reaction: see text] Hydrozirconation of terminal alkynes, followed by AgClO4-catalyzed in situ addition of the resultant alkenylzirconocenes to 1,2-anhydrosugars (glycal epoxides) leads to alpha-C-glycosides in moderate to high yields. 相似文献
28.
Pamela B. Pierce Daniel Waterman 《Proceedings of the American Mathematical Society》2004,132(3):755-760
The necessary and sufficient condition for to be in the class for every of that class whose range is in the domain of is that be in .
29.
Improved signal-to-noise ratio in spectral-domain compared with time-domain optical coherence tomography 总被引:1,自引:0,他引:1
A signal-to-noise ratio (SNR) analysis is presented for optical coherence tomography (OCT) signals in which time-domain performance is compared with that of the spectral domain. A significant SNR gain of several hundredfold is found for acquisition in the spectral domain. The SNR benefit is demonstrated experimentally in a hybrid time-domain-spectral-domain OCT system. 相似文献
30.
Wm. Lerch R. H. Bogue E. S. Shepherd G. A. Rankin F. E. Wright F. Ferrari J. Stanton Pierce W. C. Setzer F. Strumpf und R. H. H. Stanger 《Fresenius' Journal of Analytical Chemistry》1930,81(12):476-480
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