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We present a general framework for manifestly-covariant canonical formulation of Poincaré gauge theories. We construct a general class of action that is invariant under two kinds of BRS transformations—translation and internal Lorentz—and suitable for manifestly-covariant canonical quantization. This theory contains a great number of conserved quantities, which we investigate systematically. It is also pointed out that a canonical formulation of higher-derivative theories may be obtained as a limiting case in this framework.  相似文献   
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Simulating the one-particle spectra of the infinite-well potential by a model, we study the symmetry and the shell-structure of octupole deformations as well as the possible occurrence of octupole (and quadrupole) instabilities. Among various types of octupole deformations investigated theY 32-type deformation is found to have a strong shell-structure as well as a very interesting symmetry which leads to the occurrence of highly-degenerate single-particle levels. One particle spectra of the octupole-coupled two-level model (withl andl + 3) are analytically studied in the limit of large angular-momentum,l.  相似文献   
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Nucleons with very small binding energies present in nuclei far from the β stability line produce a unique shell structure, which leads to the disappearance of traditional magic numbers or to the creation of new magic numbers and new deformation regions. We study the shell structure in terms of the variation of two important ingredients, the kinetic energy and the spin-orbit splitting, as a function of the orbital angular momentum ℓ, when binding energies of neutrons decrease towards zero. It is also shown that for low-lying threshold strength, a negative sign is possible for the polarization charge coming from the coupling of one-particle to isoscalar shape oscillations. Received: 1 May 2001 / Accepted: 4 December 2001  相似文献   
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Lysocin E, a macrocyclic peptide, exhibits potent antibacterial activity against methicillin‐resistant Staphylococcus aureus (MRSA) through a novel mechanism. The first total synthesis of lysocin E was achieved by applying a full solid‐phase strategy. The developed approach also provides rapid access to the enantiomeric, epimeric, and N‐demethylated analogues of lysocin E. Significantly, the antibacterial activity of the unnatural enantiomer was comparable to that of the natural isomer, suggesting the absence of chiral recognition in its mode of action.  相似文献   
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Condensation of glycosylated arylaldehyde with acetylacetone-B(2)O(3) complex gave a corresponding diglycosylcurcuminoid, and a similar reaction using a mixture of arylaldehyde and glycosylarylaldehyde gave an unsymmetrical monoglycosylcurcuminoid, both as boron-complexes. The boron was removed from the complexes by heating in methanol, thus achieving the synthesis of di- and mono-glycosylcurcuminoids.  相似文献   
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