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51.
We answer some questions posed in [L. Grunenfelder, M. Mastnak, On bimeasurings, J. Pure Appl. Algebra 204 (2006) 258-269] concerning the universal bimeasuring bialgebra via a construction of suitable subcoalgebras of the universal measuring coalgebra. 相似文献
52.
In this article, we generalize the theory of motivic integration on formal schemes topologically of finite type and the notion
of motivic Serre invariant, to a relative point of view. We compute the relative motivic Serre invariant for curves defined
over the field of fractions of a complete discrete valuation ring R of equicharacteristic zero. One aim of this study is to understand the behavior of motivic Serre invariants under ramified
extension of the ring R. Thanks to our constructions, we obtain, in particular, an expression for the generating power series, whose coefficients
are the motivic Serre invariant associated to a curve, computed on a tower of ramified extensions of R. We give an interpretation of this series in terms of the motivic zeta function of Denef and Loeser. 相似文献
53.
Samit Mandal T. Madhusoodhanan Subinit Roy S. Ray H. Majumdar S. Datta S. S. Ghugre S. Ghosh A. Mandal D. K. Avasthi S. K. Datta 《Nuclear Physics A》2003,720(3-4):222-244
Angular distributions of elastic scattering and inelastic scattering from 2+1 state are measured for 16O+142,144,146Nd systems at several energies in the vicinity of the Coulomb barrier. The angular distributions are systematically analyzed in coupled channel framework. Renormalized double folded real optical and coupling potentials with DDM3Y interaction have been used in the calculation. Relevant nuclear densities needed to generate the potentials are derived from shell model wavefunctions. A truncated shell model calculation has been performed and the calculated energy levels are compared with the experimental ones. To simulate the absorption, a ‘hybrid’ approach is adopted. The contribution to the imaginary potential of couplings to the inelastic channels, other than the 2+1 target excitation channel, is calculated in the Feshbach formalism. This calculated imaginary potential along with a short ranged volume Woods–Saxon potential to simulate the absorption in fusion channel reproduces the angular distributions for 16O+146Nd quite well. But for 16O+142,144Nd systems additional surface absorption is found to be necessary to fit the angular distribution data. The variations of this additional absorption term with incident energy and the mass of the target are explored. 相似文献
54.
Almost thirty years ago, Penny G. Estabrooks asked “Where and what are the scalar mesons?” (P. Estabrooks, Phys. Rev. D 19, 2678 (1979)). The first part of her question can now be confidently responded (E. van Beveren et al., Z. Phys. C 30, 615 (1986)). However, with respect to the “What” many puzzles remain unanswered. Scalar and axial-vector mesons form part
of a large family of mesons. Consequently, though it is useful to pay them some extra attention, there is no point in discussing
them as isolated phenomena. The particularity of structures in the scattering of --basically-- pions and kaons with zero angular
momentum is the absence of the centrifugal barrier, which allows us to “see” strong interactions at short distances. Experimentally
observed differences and similarities between scalar and axial-vector mesons on the one hand, and other mesons on the other
hand, are very instructive for further studies. Nowadays, there exists an abundance of theoretical approaches towards the
mesonic spectrum, ranging from confinement models of all kinds, i.e., glueballs, and quark-antiquark, multiquark and hybrid configurations, to models in which only mesonic degrees of freedom
are taken into account. Nature seems to come out somewhere in the middle, neither preferring pure bound states, nor effective
meson-meson physics with only coupling constants and possibly form factors. As a matter of fact, apart from a few exceptions,
like pions and kaons, Nature does not allow us to study mesonic bound states of any kind, which is equivalent to saying that
such states do not really exist. Hence, instead of extrapolating from pions and kaons to the remainder of the meson family,
it is more democratic to consider pions and kaons mesonic resonances that happen to come out below the lowest threshold for
strong decay. Nevertheless, confinement is an important ingredient for understanding the many regularities observed in mesonic
spectra. Therefore, excluding quark degrees of freedom is also not the most obvious way of describing mesons in general, and
scalars and axial-vectors in particular. 相似文献
55.
Suchada Suntornchashwej Dr. Khanit Suwanborirux Dr. Kazushi Koga Minoru Isobe Prof. Dr. 《化学:亚洲杂志》2007,2(1):114-122
Malyngamide X ( 1 ), the first (7R)‐lyngbic acid connected to a new tripeptide backbone, was isolated from the Thai sea hare Bursatella leachii. The gross structure of 1 was established on the basis of 1D and 2D NMR and mass spectroscopic data. Combination of the NMR spectroscopic experiments with α‐methoxy‐α‐(trifluoromethyl)phenylacetic acid esters, 2,2,2‐trifluoro‐1‐(9‐anthryl)ethanol chiral solvating agent, and molecular mechanics of 1 and the synthetic molecular fragments allowed us to determine the absolute stereochemistry of all six stereogenic centers without hydrolytic degradation of the compound. Compound 1 displayed moderate cytotoxic, antitubercular, and antimalarial properties. 相似文献
56.
用遗传算法结合Gupta紧束缚模型势研究了Irn(n=2-25)团簇的基态结构.分析了Irn(n=2-25)团簇的基态结构随团簇尺寸的变化规律.计算结果表明,Irn(n=2-25)团簇的每个原子的平均束缚能和平均第一近邻随团簇尺寸的增加而增大,以总束缚能的二阶差分为判据,Irn(n=2-25)团簇的幻数是4、7、9、13、15、19、23. 相似文献
57.
58.
CuX(X=Al, Ga, In)分子的势能函数与稳定性的密度泛函研究 总被引:5,自引:3,他引:2
刘风丽 《原子与分子物理学报》2006,23(5):838-842
根据原子分子反应静力学原理导出了CuX(X=Al,Ga,In) 分子基态电子状态及其离解极限,并在B3LYP/LANL2DZ水平上计算了平衡几何、振动频率和解离能.利用Murrell-Sorbie 函数拟合出了解析势能函数,并计算出光谱参数和力常数.计算结果表明该分子体系是稳定存在的,其稳定性排序为 CuAl>CuGa>CuIn. 相似文献
59.
Piotr Niemiec 《Topology and its Applications》2006,153(18):3373-3382
Equicontinuous semigroups of transformations of a compact Hausdorff space and their sets of all invariant (Borel, regular and probabilistic) measures are studied. Conditions equivalent to the existence of at least one invariant measure are given. The (algebraic and topological) structure of the set of invariant measures is researched. 相似文献
60.
《Surface and interface analysis : SIA》2006,38(3):150-157
The role of water‐soluble corrosion products on galvanized wires was examined. The samples used were industrial hot‐dip galvanized wires, which were exposed to the open air under all weather conditions for a relatively short time (6 and 12 months), in an urban environment close to the sea. The samples were studied by different methods, i.e. scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD) and optical microscopy (OM). Several phases were detected because of the galvanization procedure and the steel substrate. Furthermore, phases which were formed as a result of the reaction of zinc with the atmosphere were also detected. These were oxides like ZnO, carbonates like ZnCO3 and hydrated Zn and Fe sulfates. Their presence influences the corrosion resistance of the wires, which finally, strongly depends on the solubility of the wires in water. The SO42? compounds especially are very soluble and consequently are easily removed from the coating surface, leading to its degradation by the formation of cavities. In any case, their presence, even after a short period of exposure, implies that the coating is highly affected by the atmosphere of the modern city. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献