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排序方式: 共有323条查询结果,搜索用时 15 毫秒
31.
Spencer Bloch Hélène Esnault Dirk Kreimer 《Communications in Mathematical Physics》2006,267(1):181-225
The appearance of multiple zeta values in anomalous dimensions and β-functions of renormalizable quantum field theories has given evidence towards a motivic interpretation of these renormalization group functions. In this paper we start to hunt the motive, restricting our attention to a subclass of graphs in four dimensional scalar field theory which give scheme independent contributions to the above functions. 相似文献
32.
We report an intrinsically stable quantum key distribution scheme based on genuine frequency-coded quantum states. The qubits are efficiently processed without fiber interferometers by fully exploiting the nonlinear interaction occurring in electro-optic phase modulators. The system requires only integrated off-the-shelf devices and could be used with a true single-photon source. Preliminary experiments have been performed with weak laser pulses and have demonstrated the feasibility of this new setup. 相似文献
33.
Nonholonomic mechanical systems with symmetry 总被引:15,自引:0,他引:15
34.
P. Knauth H. HouE. Bloch E. SgrecciaM.L. Di Vona 《Journal of Analytical and Applied Pyrolysis》2011,92(2):361-365
Thermal degradation of SPEEK membranes is studied by coupling thermogravimetric analysis (TGA) and mass spectrometry (MS). Main mass losses can be attributed to water evaporation, desulfonation and oxidative pyrolysis of polymer main chain. The analysis can be used to determine the degree of sulfonation (DS) and the degree of cross-linking (DCL) between macromolecular chains. Furthermore, the thermogravimetric curves can be modelled using non-isothermal chemical kinetics, allowing determination of activation energies during thermal degradation of SPEEK membranes. 相似文献
35.
Hekmat D Mornhinweg R Bloch G Sun Y Jeanty P Neubert M Weuster-Botz D 《Journal of chromatography. A》2011,1218(7):944-950
The goal of the present work was to examine the hydrodynamic behavior of preparative scale packed chromatography beds during long-term cyclical operation at high loads using an experimental set-up with a high resolution measuring device of bed height. One agarose-based resin and one methacrylic-based resin were examined in a 140 mm column. Both resins exhibited hysteresis behavior during compression/relaxation cycles. The hystereses were less pronounced with decreasing hydrodynamic stress rate. The occurrence of hystereses was an indication for hydrodynamic memory behavior of the chromatography packing. During long-term cyclical operation at high loads of the column filled with methacrylic resin, oscillations of the steadily with time decreasing flow rate were observed for the first time. These oscillations were attributed to the viscoelasticity of the polymer particles network representing a system with materials with fading memory. Such nonlinear systems with feed-back are known to exhibit inherent self-oscillations. A decoupling of the two processes of bed compression and decrease of bed permeability was observed. The presented results explain why preparative packed-bed chromatography often yields unsatisfactory reproducible data and why unwanted phenomena like medium wall detachment or other symptoms of deteriorated chromatography beds are frequently observed. 相似文献
36.
Definitions of equilibrium in network formation games 总被引:1,自引:0,他引:1
We examine a variety of stability and equilibrium definitions that have been used to study the formation of social networks among a group of players. In particular we compare variations on three types of definitions: those based on a pairwise stability notion, those based on the Nash equilibria of a link formation game, and those based on equilibria of a link formation game where transfers are possible.Bloch is also affiliated with the University of Warwick. 相似文献
37.
This paper continues the review of the Serret-Andoyer (SA) canonical formalism in rigid-body dynamics, commenced by [1], and
presents some new result. We discuss the applications of the SA formalism to control theory. Considerable attention is devoted
to the geometry of the Andoyer variables and to the modeling of control torques. We develop a new approach to Stabilization
of rigid-body dynamics, an approach wherein the state-space model is formulated through sets of canonical elements that partially
or completely reduce the unperturbed Euler-Poinsot problem. The controllability of the system model is examined using the
notion of accessibility, and is shown to be accessible. Based on the accessibility proof, a Hamiltonian controller is derived
by using the Hamiltonian as a natural Lyapunov function for the closed-loop dynamics. It is shown that the Hamiltonian controller
is both passive and inverse optimal with respect to a meaningful performance-index. Finally, we point out the possibility
to apply methods of structure-preserving control using the canonical Andoyer variables, and we illustrate this approach on
rigid bodies containing internal rotors.
相似文献
38.
Ohne Zusammenfassung 相似文献
39.
Muse Oke RosalindTanYan Ching LesterG. Carter KennethA. Johnson Huanting Liu StephenA. McMahon MalcolmF. White Carlos Bloch CatherineH. Botting MartinA. Walsh AishahA. Latiff MalcolmW. Kennedy Alan Cooper JamesH. Naismith 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2008,120(41):7971-7974
40.
We address in this paper the problem of defining belief functions, typically for multi-source classification applications in image processing. We propose to use mathematical morphology for introducing imprecision in the mass and belief functions while estimating disjunctions of hypotheses. The basic idea relies on the similarity between some properties of morphological operators and properties of belief functions. The framework of mathematical morphology guarantees that the derived functions have all required properties. We illustrate the proposed approach on synthetic and real images. 相似文献