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941.
This paper is concerned with the spectral analysis of a one-velocity transport operator with Maxwell boundary condition in
L
1-space. After a detailed spectral analysis it is shown that the associated Cauchy problem is governed by a C
0-semigroup. Next, we discuss the irreducibility of the transport semigroup. In particular, we show that the transport semigroup
is irreducible. Finally, a spectral decomposition of the solutions into an asymptotic term and a transient one which will
be estimated for smooth initial data is given. 相似文献
942.
A new method for the analysis of thermal desorption spectra is presented, based on the experimental peak maximum functions
for temperatureT
m(β) and pressureP
m(β) and a rigorous mathematical treatment. The resonant heating rate βr is determined, satisfyingT
m(βr)=T
r, whereT
r is the resonant temperature defined byA exp(−E
d/(RT
r))=1. Desorption energyE
d and frequency factorA can be determined simultaneously with relatively high robustness towards statistical experimental errors as demonstrated
by computer-simulated thermal desorption spectra. 相似文献
943.
We study the large-sample properties of a class of parametric mixture models with covariates for competing risks. The models allow general distributions for the survival times and incorporate the idea of long-term survivors. Asymptotic results are obtained under a commonly assumed independent censoring mechanism and some modest regularity conditions on the survival distributions. The existence, consistency, and asymptotic normality of maximum likelihood estimators for the parameters of the model are rigorously derived under general sufficient conditions. Specific conditions for particular models can be derived from the general conditions for ready check. In addition, a likelihood-ratio statistic is proposed to test various hypotheses of practical interest, and its asymptotic distribution is provided. 相似文献
944.
We give some sufficient conditions for proper lower semicontinuous functions on metric spaces to have error bounds (with exponents).
For a proper convex function f on a normed space X the existence of a local error bound implies that of a global error bound. If in addition X is a Banach space, then error bounds can be characterized by the subdifferential of f. In a reflexive Banach space X, we further obtain several sufficient and necessary conditions for the existence of error bounds in terms of the lower Dini
derivative of f.
Received: April 27, 2001 / Accepted: November 6, 2001?Published online April 12, 2002 相似文献
945.
946.
In this paper, we give a convergence theorem and error estimates for an iteration method under new Kantorovitch-Ostrowski type condition using the information of higher derivatives at initial points. Compared with the corresponding study in [3],the convergence determination is established under one global condition, instead of two , on the function. 相似文献
947.
Gary Sampson 《应用数学学报(英文版)》2002,(3)
In this paper, the authors prove that some oscillatory singular integral operators of non-convolution type with non-polynomial phases are bounded from the Herz-type Hardy spaces to the Herz spaces and from the Hardy spaces associated with the Beurling algebras to the Beurling algebras in higher dimensions, even though it is well-known that these operators are not bounded from the Hardy space H1(Rn) into the Lebesgue spaceL1(Rn). 相似文献
948.
In a recent paper [17] we proposed a stochastic algorithm which generates optimal probabilities for the decompression of
an image represented by the fixed point of an IFS system (SAOP). We show here that such an algorithm is in fact a non trivial
example of Generalized Random System with Complete Connections. We also exhibit a generalization which could represent the
solution to the inverse problem for an image with grey levels, if a fixed set of contraction maps is available.
Received: 1 July 2002 相似文献
949.
X.T Zhang Y.C LiuZ.Z Zhi J.Y ZhangY.M Lu D.Z ShenW Xu X.W FanX.G Kong 《Journal of luminescence》2002,99(2):149-154
The properties of the excitonic luminescence for nanocrystalline ZnO thin films are investigated by using the dependence of excitonic photoluminescence (PL) spectra on temperature. The ZnO thin films are prepared by thermal oxidation of ZnS films prepared by low-pressure metalorganic chemical vapor deposition (LP-MOCVD) technique. The X-ray diffraction (XRD) indicates that ZnO thin films have a polycrystalline hexagonal wurtzite structure with a preferred (0 0 2) orientation. A strong ultraviolet (UV) emission peak at 3.26 eV is observed, while the deep-level emission band is barely observable at room temperature. The strength of the exciton-longitudinal-optical (LO) phonon coupling is deduced from the temperature dependence of the full-width at half-maximum (FWHM) of the fundamental excitonic peak, decrease in exciton-longitudinal-optical (LO) phonon coupling strength is due to the quantum confinement effect. 相似文献
950.
Carolina Pereira De Souza Margareth Spangler Andrade Bernardo Ruegger Almeida Neves 《Microscopy and microanalysis》2002,8(6):509-517
In this work, effective, yet simple, recycling mechanisms for used scanning probe microscopy (SPM) tips were implemented. Comprising a tip profile characterization methodology and specific cleaning procedures, which decontaminate SPM tips whether the contamination nature is known or not, such routes were optimized during numerous tests with brand new, previously used, and already discarded categories of SPM tips. The results show that if the used tip suffered contamination only, but no physical damages, during its scanning lifetime, it becomes readily available for reutilization after the cleansing process, characterizing a recycling route. On the other hand, if the tip went through wear and breakages during its utilization, it still can be decontaminated, but may not be directly reutilized due to its inadequate physical profile. Nevertheless, the methodology developed in this work may yet be applied as part of a more complex recycling route. 相似文献