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101.
We provide a model for an open invariant neighborhood of any orbit in a symplectic manifold endowed with a canonical proper symmetry. Our results generalize the constructions of Marle and Guillemin and Sternberg for canonical symmetries that have an associated momentum map. In these papers the momentum map played a crucial role in the construction of the tubular model. The present work shows that in the construction of the tubular model, the so-called Chu map, can be used instead, which exists for any canonical action, unlike the momentum map. Hamilton's equations for any invariant Hamiltonian function take on a particularly simple form in these tubular variables. As an application we will find situations, that we will call tubewise Hamiltonian, in which the existence of a standard momentum map in invariant neighborhoods is guaranteed. 相似文献
102.
Cholesterol is an important constituent of eukaryotic cell membranes, whose interaction with phospholipids leads to a broad
range of biological roles, such as: maintenance of proper fluidity, formation of raft domains, reduction of passive permeability
of various chemical species through the bilayer (e.g., glucose, glycerol, K+, Na+ and Cl− ions), and increased mechanical strength of the membrane. In this work we studied an interesting paradigm, as to whether
cholesterol-containing phosphatidylcholine biomembranes influence the kinetics and transport features of alamethicin oligomers
embedded into it. We demonstrate that moderate relative amounts of cholesterol increase the electrical conductance of various
sub-conductance states of the alamethicin oligomer, caused probably by a non-monotonic change in the lumped dipole moment
of the biomembrane. Our data suggest that biomembrane stiffness caused by cholesterol, visibly modifies the association-dissociation
rates of alamethicin oligomerization in the biomembrane. Moreover, increasing concentrations of cholesterol seem to lead to
more stable intermediate alamethicin oligomers. We show that in the presence of cholesterol, as the diameter of the alamethicin
oligomer increases, so does the time of another monomer to get picked up. These results brings into focus the interesting
issue of how oligomerization of proteins affects their interaction affinities for membrane-based lipids. 相似文献
103.
One describes, using a detailed analysis of Atiyah-Hirzebruch spectral sequence, the tuples of cohomology classes on a compact,
complex manifold, corresponding to the Chern classes of a complex vector bundle of stable rank. This classification becomes
more effective on generalized flag manifolds, where the Lie algebra formalism and concrete integrability conditions describe
in constructive terms the Chern classes of a vector bundle.
Since deceased. 相似文献
104.
A plane graph is called symmetric if it is invariant under the reflection across some straight line (called symmetry axis). Let G be a symmetric plane graph. We prove that if there is no edge in G intersected by its symmetry axis then the number of spanning trees of G can be expressed in terms of the product of the number of spanning trees of two smaller graphs, each of which has about half the number of vertices of G. 相似文献
105.
Thallada Bhaskar Kazuya Murai Toshiki Matsui Mihai Adrian Brebu Md. Azhar Uddin Akinori Muto Yusaku Sakata Katsuhide Murata 《Journal of Analytical and Applied Pyrolysis》2003,70(2):369-381
The thermal degradation of acrylonitrile-butadiene-styrene copolymer (ABS-Br; 10 g) containing brominated flame retardant (Br: 9.59 wt.%) was carried out at 450 °C using a semi batch operation using two different temperature programs. The heating rate was found to affect the quality of the degradation oil and yield of products (liquid, gas and residue). Data on the effect of the temperature program on the accumulation of liquid products was presented. It was found that the majority of the bromine was concentrated in the carbon residue and while majority of the nitrogen accumulates in the liquid products irrespective of degradation mode. The use of a one step constant heating rate process (I) produced a higher liquid yield (39%), than a two step process (29%). Differences were also noted in the Br and N contained in the liquids produced by the two processes. 相似文献
106.
The conditions under which it is possible to reduce a Poisson manifold via a regular foliation have been completely characterized by Marsden and Ratiu. In this Letter we show that this characterization can be generalized in a natural way to the singular case and, as a corollary, we obtain that when the singular distribution is given by the tangent spaces to the orbits created by a Hamiltonian Lie group action, one reproduces the Universal Reduction Procedure of Arms, Cushman, and Gotay. 相似文献
107.
Mihai Tibăr 《Israel Journal of Mathematics》2007,157(1):309-322
We study the vanishing neighbourhood of non-isolated singularities of functions on singular spaces by associating a general
linear function. We use the carrousel monodromy in order to show how to get a better control over the attaching of thimbles.
For one-dimensional singularities, we prove obstructions to integer (co)homology groups and to the eigenspaces of the monodromy
via monodromies of nearby sections. Our standpoint allows one to find, in certain cases, the structure of the Milnor fibre
up to the homotopy type. 相似文献
108.
While the theory of operators in quantum mechanics is expressed nowadays in a pure operatorial form (wrapped mostly in Dirac's symbolic language), in optics the polarization device operators and their action are analyzed yet in the old matrix (Jones or Muller) formalism. The theory of polarization device operators has not taken systematically advantage of the very general, fundamental and deep results of the spectral theory of operators, on the basis of which it can be structured in an elegant deductive and physically expressive form. In this paper we apply the spectral theorem to the polarization device operators, we calculate their expansions in a pure operatorial Dirac-dyadic form and give some examples which illustrate the advantages from the physical insight viewpoint of such an approach. We are concerning here only with the basic polarization devices, to which correspond normal operators. 相似文献
109.
110.