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241.
Boris Kaufmann 《Mathematische Annalen》1930,103(1):70-144
Ohne Zusammenfassung 相似文献
242.
We show that n lines in 3-space can be cut into
O(n2-1/69log16/69n) pieces, such that all depth cycles
defined by triples of lines are eliminated. This partially resolves
a long-standing open problem in computational geometry, motivated by
hidden-surface removal in computer graphics. 相似文献
243.
We study representations of affine Kac-Moody algebras from a geometric point of view. It is shown that Wakimoto modules introduced in [18], which are important in conformal field theory, correspond to certain sheaves on a semi-infinite flag manifold with support on its Schhubert cells. This manifold is equipped with a remarkable semi-infinite structure, which is discussed; in particular, the semi-infinite homology of this manifold is computed. The Cousin-Grothendieck resolution of an invertible sheaf on a semi-infinite flag manifold gives a two-sided resolution of an irreducible representation of an affine algebras, consisting of Wakimoto modules. This is just the BRST complex. As a byproduct we compute the homology of an algebra of currents on the real line with values in a nilpotent Lie algebra.Dedicated to Dmitry Borisovich Fuchs on his 50th birthdayAddress after September 15, 1989: Mathematics Department, Harvard University, Cambrdige, MA 02138, USA 相似文献
244.
We give a simple proof of I. Krichever's theorem on rational reductions of the Kadomtsev–Petviashvili hierarchy by using the Poisson–Lie structure on the group of pseudo-differential symbols. 相似文献
245.
Boris N. Kuznetsov Svetlana A. Kuznetsova Vladimir G. Danilov Olga V. Yatsenkova 《Reaction Kinetics and Catalysis Letters》2009,97(2):295-300
Some regularities of abies-wood oxidative delignification by acetic acid–hydrogen peroxide mixture under the action of suspended
TiO2 catalyst and UV pretreatment of wood pulp were studied. The combined action of TiO2 catalyst and of UV-pretreatment of abies-wood allow to produce at optimal conditions of the delignification process the chemically
pure cellulose containing no residual lignin. The major characteristics of cellulose product obtained from abies-wood correspond
to the characteristics of microcrystalline cellulose. 相似文献
246.
Yoav Linzon Boris A. Malomed Michael Zaezjev Roberto Morandotti Maite Volatier Vincent Aimez Richard Ares Shimshon Bar-Ad 《Central European Journal of Physics》2008,6(3):555-562
We study nonlinear interactions between discrete optical solitons that propagate in different regimes of diffraction, and
the nonlinear scattering of dispersive waves by local optical potentials. It is well known in optics that when linear coherent
waves meet, they interfere without interactions. Linear waves also scatter through local optical structures not exchanging
any power with the guided modes of these structures. As a focusing Kerr nonlinearity is present, such linearly-inhibited phenomena
can exist. Our studies are performed in silica and AlGaAs nonlinear waveguides, excited by ultra-short pulses in the near
infrared.
Presented at 9-th International Workshop on Nonlinear Optics Applications, NOA 2007, May 17–20, 2007, Świnoujście, Poland 相似文献
247.
We prove that a primitive substitution Delone set, which is pure point diffractive, is a Meyer set. This answers a question
of J.C. Lagarias. We also show that for primitive substitution Delone sets, being a Meyer set is equivalent to having a relatively
dense set of Bragg peaks. The proof is based on tiling dynamical systems and the connection between the diffraction and dynamical
spectra.
The first author acknowledges support from the NSERC post-doctoral fellowship and thanks the University of Washington and
the University of Victoria for being the host universities of the fellowship. The second author is grateful to the Weizmann
Institute of Science where he was a Rosi and Max Varon Visiting Professor when this work was completed. He was also supported
in part by NSF Grant DMS 0355187. 相似文献
248.
249.
Marcus Walter Joseph Somers Boris Brendebach 《Journal of solid state chemistry》2009,182(12):3305-12445
Yttria stabilised zirconia (YSZ) based (Zr,Y,U)O2−x and (Zr,Y,Np)O2−x solid solutions with 6 and 20 mol% actinide were prepared with Y/Zr ratios ranging from 0.2 to 2.0 to investigate uranium and neptunium oxidation behaviour depending on the oxygen vacancies in the defect fluorite lattice. Sintering at 1600 °C in Ar/H2 yields a cubic, fluorite-type structure with U(IV) and Np(IV). Annealing (Zr,Y,U)O2−x with Y/Zr=0.2 at 800 °C in air results in a tetragonal phase, whereas (Zr,Y,U)O2−x with higher Y/Zr ratios and (Zr,Y,Np)O2−x retain the cubic structure. XANES and O/M measurements indicate mixed U(V)-U(VI) and Np(IV)-Np(V) oxidation states after oxidation. Based on X-ray diffraction, O/M and EXAFS measurements, different oxidation mechanisms are identified for U- and Np-doped stabilised zirconia. In contrast to U, excess oxygen vacancies are needed to oxidise Np in (Zr,Y,Np)O2−x as the oxidation process competes with Zr for oxygen vacancies. As a consequence, U(VI) and Np(V) can only be obtained in stabilised zirconia with Y/Zr=1 but not in YSZ with Y/Zr=0.2. 相似文献
250.