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91.
Martin Breza 《Czechoslovak Journal of Physics》1992,42(2):201-207
The electronic structure of YBa2Cu3Ox (x=6 and 7) is investigated using the CNDO molecular orbital method. Electronic structures of model clusters [Cu3O10]–15, [Ba8Cu3O10]+1, [Y8Cu3O10]+9 of the non-superconducting (x=6) and [Cu3O12]–17, [Ba8Cu3O12]–1, [Y8Cu3O12]+7 of the superconducting (x=7) phases are compared. Y and Ba layers cause a considerable electron density transfer from the central Cu(1) region. 相似文献
92.
Martin E. V. Pedersen Lars S. Rishøj Henrik Steffensen Sanshui Xiao Niels Asger Mortensen 《Optical and Quantum Electronics》2007,39(10-11):903-911
Slow-light enhanced optical detection in liquid-infiltrated photonic crystals is theoretically studied. Using a scattering-matrix approach and the Wigner–Smith delay time concept, we show that optical absorbance benefits both from slow-light phenomena as well as a high filling factor of the energy residing in the liquid. Utilizing strongly dispersive photonic crystal structures, we numerically demonstrate how liquid-infiltrated photonic crystals facilitate enhanced light–matter interactions, by potentially up to an order of magnitude. The proposed concept provides strong opportunities for improving existing miniaturized absorbance cells for optical detection in lab-on-a-chip systems. 相似文献
93.
Martin Traizet 《Commentarii Mathematici Helvetici》2004,79(4):798-825
We prove a balancing condition for weak limits of
families of embedded
minimal surfaces of finite total curvature. We use it to
prove compactness theorems for certain families of minimal
surfaces. 相似文献
94.
95.
96.
Let G be a d‐regular graph G on n vertices. Suppose that the adjacency matrix of G is such that the eigenvalue λ which is second largest in absolute value satisfies λ = o(d). Let Gp with p = α/d be obtained from G by including each edge of G independently with probability p. We show that if α < 1, then whp the maximum component size of Gp is O(log n) and if α > 1, then Gp contains a unique giant component of size Ω(n), with all other components of size O(log n). © 2003 Wiley Periodicals, Inc. Random Struct. Alg., 2004 相似文献
97.
Stewart S. J. Mercader R. C. Punte G. Desimoni J. Cernicchiaro G. Scorzelli R. B. 《Hyperfine Interactions》2004,158(1-4):89-93
In this paper we analyze trend of EFG values measured at Cd impurity in a group of semiconducting delafossites with chemical
formula CuBO2 (B = Al, Fe, Cr, Nd). We conclude that this trend reveals one of the most subtle details in electronic spectrum of the compounds:
if impurity states are formed within or out of the band gap. In CuAlO2 and CuFeO2 the Cd EFG exhibits larger value than in CuCrO2 and CuNdO2, when Cd substitutes the Cu atom. This occurs because in the first two compounds the Cd forms shallow band within the gap,
and in the second two compounds does not. When Cd occupies the B position it exhibits almost the same EFG in all delafossites.
In this case, Cd does not form its states within the gap in none of the compounds. To arrive to these conclusions we analyzed
and calculated various systems (Cd-doped CuAlO2 and CuCrO2 compounds, fictitious molecules), using the FP-LAPW method. 相似文献
98.
99.
Casey Chun Zhou Eric J. Stoner Kent D. Stewart L. Steven Hollis Edmund D. Matayoshi Gregory M. Brill 《Tetrahedron》2004,60(47):10611-10618
Oritavancin is a semi-synthetic glycopeptide antibiotic which is structurally related to vancomycin. When oritavancin bisphosphate is dried in vacuo with heat, a new compound forms. This new compound is stable only in the solid state and reverts to oritavancin in solution. Highly enriched samples of this compound were obtained by preparative HPLC and the structure of this compound was elucidated by using one and two-dimensional (1H and 13C) NMR spectroscopy in conjunction with computer-assisted molecular modeling. It has been determined that oritavancin adopts a conformation similar to that of vancomycin in solution, while the new compound is the unnatural R-AB-biaryl atropisomer of oritavancin. This is the first observation and isolation of an AB-biaryl atropisomer in an intact member of the vancomycin family of glycopeptide antibiotics. 相似文献
100.
Martin R. Bridson Charles F. Miller III 《Proceedings of the American Mathematical Society》2004,132(1):59-65
We give examples of direct products of three hyperbolic groups in which there cannot exist an algorithm to decide which finitely presented subgroups are isomorphic.