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41.
Yi-Zhi HUANG 《数学年刊B辑(英文版)》2022,43(6):1101-1124
Convergence and analytic extension are of fundamental importance in the mathematical construction and study of conformal field theory. The author reviews some main convergence results, conjectures and problems in the construction and study of conformal field theories using the representation theory of vertex operator algebras. He also reviews the related analytic extension results, conjectures and problems. He discusses the convergence and analytic extensions of products of intertwining operators (chiral conformal fields) and of q-traces and pseudo-q-traces of products of intertwining operators. He also discusses the convergence results related to the sewing operation and the determinant line bundle and a higher-genus convergence result. He then explains conjectures and problems on the convergence and analytic extensions in orbifold conformal field theory and in the cohomology theory of vertex operator algebras. 相似文献
42.
Yoshinobu Kamishima 《Annals of Global Analysis and Geometry》1994,12(1):261-289
A strictly pseudoconvex pseudo-Hermitian manifoldM admits a canonical Lorentz metric as well as a canonical Riemannian metric. Using these metrics, we can define a curvaturelike function onM. AsM supports a contact form, there exists a characteristic vector field dual to the contact structure. If induces a local one-parameter group ofCR transformations, then a strictly pseudoconvex pseudo-Hermitian manifoldM is said to be a standard pseudo-Hermitian manifold. We study topological and geometric properties of standard pseudo-Hermitian manifolds of positive curvature or of nonpositive curvature . By the definition, standard pseudo-Hermitian manifolds are calledK-contact manifolds by Sasaki. In particular, standard pseudo-Hermitian manifolds of constant curvature turn out to be Sasakian space forms. It is well known that a conformally flat manifold contains a class of Riemannian manifolds of constant curvature. A sphericalCR manifold is aCR manifold whose Chern-Moser curvature form vanishes (equivalently, Weyl pseudo-conformal curvature tensor vanishes). In contrast, it is emphasized that a sphericalCR manifold contains a class of standard pseudo-Hermitian manifolds of constant curvature (i.e., Sasakian space forms). We shall classify those compact Sasakian space forms. When 0, standard pseudo-Hermitian closed aspherical manifolds are shown to be Seifert fiber spaces. We consider a deformation of standard pseudo-Hermitian structure preserving a sphericalCR structure.Dedicated to Professor Sasao Seiya for his sixtieth birthday 相似文献
43.
44.
B. Pes J.M. Paul J.M. Corpart M. Sindt J.L. Mieloszynski 《European Polymer Journal》2004,40(12):2727-2730
A series of ω-perfluorooctyl-alkyl polyacrylates has been prepared and analysed. The odd–even effect, already observed in the case of liquid crystalline polymers has been exhibited for perfluorinated ones. Values of the contact angles to advanced (θa), with withdrawal (θr), as well as the contact angle hysteresis (Δθ) of various ω-perfluorooctyl-alkyl polyacrylates in water at 20 °C are described. Contrary to the advancing contact angle which is almost independent of spacer length, the receding one varies strongly with it. 相似文献
45.
Samuel O. Asekomhe Janet A. W. Elliott 《Colloids and surfaces. A, Physicochemical and engineering aspects》2003,220(1-3):271-278
Much research has been done on line tension measurement and interpretation, and attempts have also been made to measure line tension with simple, cheap and reliable methods that do not require excessive sophistication. Of particular interest is the method of determining line tensions of solid–liquid–vapor systems from the capillary rise in a conical tube. This simple and relatively inexpensive method gives line tension values comparable to those reported in the literature obtained via highly sophisticated instruments or techniques such as the well known axisymmetric drop shape analysis technique. The absolute value of line tension obtained using the conical tube method and assuming a spherical liquid–vapor interface is larger but of the same order of magnitude (1 μJ m−1) as that reported in the literature. A theoretical analysis presented herein shows that by including the deformation of the liquid–vapor interface due to gravity in the conical capillary analysis, the line tension value inferred from the experimental data is reduced by approximately 50% and compares better with values in the literature obtained using other sophisticated methods. Thus a relatively simple, cheap, accurate and reliable method of line tension measurement has been advanced. 相似文献
46.
The Hamaker constant of unsized intermediate modulus carbon fibers was evaluated by contact angle measurement following the Fowkes theory of interfacial energetics. The effects of a surface treatment (performed by the manufacturer) and an oxygen plasma treatment (performed by us), both of oxidizing nature, proved to slightly increase the value of the Hamaker constant to a level that enhanced by about 9% the Lifshitz-van der Waals contribution to the theoretical adhesion force between the fiber and an epoxy matrix. A possible explanation of the observed increase of the Hamaker constant is the higher contribution to the overall Lifshitz-van der Waals interaction of Keesom (orientation) and Debye (induction) forces. 相似文献
47.
Jin Chen Lin-xi Zhang A-gen Xia 《高分子科学》2006,(1):13-19
It is important to know the rate of intra-molecular contact formation in proteins in order to understand how proteins fold clearly. Here we investigate the rate of intra-molecular contact formation in short two-dimensional compact polymer chains by calculating the probability distribution p(r) of end-to-end distance r using the enumeration calculation method and HP model on two-dimensional square lattice. The probability distribution of end-to-end distance p(r) of short two-dimensional compact polymers chains may consist of two parts, i.e. p(r) = p1(r) p2(r), where p1(r) and p2(r) are different for small r. The rate of contact formation decreases monotonically with the number of bonds N, and the rate approximately conforms to the scaling relation of k(N) ∝ N-α. Here the value of α increases with the contact radius a and it also depends on the percentage of H (hydrophobic) residues in the sequences of compact chains and the energy parameters of εHH, εHP and εPP . Some comparisons of theoretical predictions with experimental results are also made. This investigation may help us to understand the protein folding. 相似文献
48.
Multi-dimple phenomena in TEHL point contacts 总被引:3,自引:0,他引:3
Theoretical analysis and experimental measurement of the multiple dimples in thermal elastohydrodynamic lubrication (TEHL) point contacts have been carried out. Good agreement is found between the theoretical and experimental results. A thermal multi-spike theory is proposed to explain the multi-dimple phenomena. 相似文献
49.
On the structure formation of hydrophobed particles in the boundary layer of water and octane phases
Two-dimensional aggregation of the surface modified glass beads was carried out in the boundary layer of water and octane phases. The effect of particles' hydrophobicity was investigated on the structure of forming aggregates and the growth process. The structure of the aggregates and their growth were characterized by a density function which demonstrates the change of mean particle density as a function of aggregate size. The growth yielded fractal or nonfractal structures in the investigated systems. The fractal structure of the aggregates was observed to be dependent on restructuring processes controlled by the surface properties of the beads.The experimental results are compared with earlier findings for aggregation of hydrophobic beads in the boundary layer of water and air phases.On leave from Loránd Eötvös University, Budapest, Hungary 相似文献
50.