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41.
We consider problems of the following type. Assign independently to each vertex of the square lattice the value +1, with
probability p, or −1, with probability 1 −p. We ask whether an infinite path π exists, with the property that the partial sums of the ±1s along π are uniformly bounded,
and whether there exists an infinite path π' with the property that the partial sums along π' are equal to zero infinitely
often. The answers to these question depend on the type of path one allows, the value of p and the uniform bound specified. We show that phase transitions occur for these phenomena. Moreover, we make a surprising
connection between the problem of finding a path to infinity (not necessarily self-avoiding, but visiting each vertex at most
finitely many times) with a given bound on the partial sums, and the classical Boolean model with squares around the points
of a Poisson process in the plane. For the recurrence problem, we also show that the probability of finding such a path is
monotone in p, for p≥?.
Received: 10 January 2000 / Revised version: 14 August 2000 / Published online: 9 March 2001 相似文献
42.
Lizhong Peng 《Bulletin des Sciences Mathématiques》2008,132(1):78
In this paper, we define the Wigner transform and the corresponding Weyl transform associated with the Heisenberg group. We established some harmonic analysis results. Then we present that the Weyl transform with the Sp-valued symbol in Lp (p∈[1,2]) is not only bounded but also compacted, while when 2<p<+∞, the Weyl transform is not a bounded operator. 相似文献
43.
This paper describes a new approach to the problem of computing spherical expansions of zonal functions on Euclidean spheres.
We derive an explicit formula for the coefficients of the expansion expressing them in terms of the Taylor coefficients of
the profile function rather than (as done usually) in terms of its integrals against Gegenbauer polynomials. Our proof of
this result is based on a polynomial identity equivalent to the canonical decomposition of homogeneous polynomials and uses
only basic properties of this decomposition together with simple facts concerning zonal harmonic polynomials. As corollaries,
we obtain direct and apparently new derivations of the so-called plane wave expansion and of the expansion of the Poisson
kernel for the unit ball.
Received: 26 January 2007 相似文献
44.
Ahmadreza Azimifard 《Monatshefte für Mathematik》2008,155(1):1-13
Let UC(K) denote the Banach space of all bounded uniformly continuous functions on a hypergroup K. The main results of this article concern the α-amenability of UC(K) and quotient and product of hypergroups. It is also shown that a Sturm-Liouville hypergroup with a positive index is α-amenable
if and only if α = 1.
Author’s address: Dietlinden Stra?e 16, 80802 München, Germany 相似文献
45.
A solid-state rotational-echo double resonance (REDOR) NMR method was introduced to identify the ?- and ψ-torsion angle from a 1H–15N or 1H–13C′ spin system of alanine-like residues in a selectively, uniformly, or extensively 15N-/13C-labeled peptide. When a Cα(i) or a 15N peak is site-specifically obtainable in the NMR spectrum of a uniformly 15N/13C-labeled sample system, the ψ- or ?-torsion angle specified by the conformational structure of peptide geometry involving 15N(i)–1Hαi–15N(i + 1) or 13C′(i − 1)–1HNi–13C′(i) spin system can be identified based on 13Cα- or 15N-detected 1Hα–15N or 1HN–13C REDOR experiment. This method will conveniently be utilized to identify major secondary motifs, such as α-helix, β-sheet, and β-turn, from a uniformly 15N-/13C-labled peptide sample system. When tested on a 13C-/15N-labeled model system of a three amino acid peptide Gly–[U–13C, 15N]Ala–[U–13C, 15N]Leu, the ψ-angle of alanine obtained experimentally, ψ = −40 ± 30°, agreed reasonably well with the X-ray determined angle, ψ = −39°. 相似文献
46.
MacDonald JL Werner-Zwanziger U Chen B Zwanziger JW Forgeron D 《Solid state nuclear magnetic resonance》2011,40(2):78-83
43Ca and 13C NMR methods were used to study the chemical interaction of poly(ethylene–vinyl acetate) (PEVAc) admixture in commercial-grade white cement. From 43Ca NMR it is shown both that PEVAc induces modest changes in the hydrated cement structure, and that hydrated commercial cement is significantly more complex than models that have been used for its structure in past work. The 13C NMR results show that the PEVAc hydrolysis occurs early in the cement hydration acceleration period, with a rate well-fit by an exponential decay using a time constant of 6±1 days. 相似文献
47.
对熔体急冷法制备的Fe43Co43Hf7B6Cu1非晶合金进行了200,300,400和500 ℃保温30 min的退火处理,用正电子湮没寿命谱、X射线衍射、穆斯堡尔谱等方法研究了退火后试样的结构及结构缺陷变化.结果表明,在非晶合金的制备态,正电子主要在非晶基体相空位尺寸的自由体积中湮没,湮没寿命τ1为158.4 ps,强度I1关键词:
43Co43Hf7B6Cu1非晶')" href="#">Fe43Co43Hf7B6Cu1非晶
退火处理
正电子湮没寿命
结构与结构缺陷 相似文献
48.
49.
In this paper, we present a new anisotropic generalization of the continuous shearlet transformation. This is achieved by means of an explicit construction of a family of reproducing Lie subgroups of the symplectic group. We study the properties of this new family of anisotropic shearlet transformations. In particular, we provide an analog of the Calder43;n admissibility condition for anisotropic shearlet reproducing functions. 相似文献
50.
We prove a multiplier theorem for certain Laplacians with drift on Damek–Ricci spaces, which are a class of Lie groups of exponential growth. Our theorem generalizes previous results obtained by W. Hebisch, G. Mauceri and S. Meda on Lie groups of polynomial growth. 相似文献