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131.
We study the metrical theory of fibred systems, in particular, in the case of continued fraction mixing systems. We get the
limit distribution of the largest value of a continued fraction mixing stationary stochastic process with infinite expectation
and some related results. These are analogous to J. Galambos, W. Philipp, and H. G. Diamond–J. D. Vaaler theorems for the
regular continued fractions. As an application, we see that these theorems hold for Jacobi-Perron algorithm.
Received September 30, 2001; in revised form January 8, 2002 相似文献
132.
The parameters that affect the shape of the band profiles of acido‐basic compounds under moderately overloaded conditions (sample size less than 500 nmol for a conventional column) in RPLC are discussed. Only analytes that have a single pKa are considered. In the buffer mobile phase used for their elution, their dissociation may, under certain conditions, cause a significant pH perturbation during the passage of the band. Two consecutive injections (3.3 and 10 μL) of each one of three sample solutions (0.5, 5, and 50 mM) of ten compounds were injected on five C18‐bonded packing materials, including the 5 μm Xterra‐C18 (121 Å), 5 μm Gemini‐C18 (110 Å), 5 μm Luna‐C18(2) (93 Å), 3.5 μm Extend‐C18 (80 Å), and 2.7 μm Halo‐C18 (90 Å). The mobile phase was an aqueous solution of methanol buffered at a constant WWpH of 6, with a phosphate buffer. The total concentration of the phosphate groups was constant at 50 mM. The methanol concentration was adjusted to keep all the retention factors between 1 and 10. The compounds injected were phenol, caffeine, 3‐phenyl 1‐propanol, 2‐phenyl butyric acid, amphetamine, aniline, benzylamine, p‐toluidine, procainamidium chloride, and propranololium chloride. Depending on the relative values of the analyte pKa and the buffer solution pH, these analytes elute as the neutral, the cationic, or the anionic species. The influence of structural parameters such as the charge, the size, and the hydrophobicity of the analytes on the shape of its overloaded band profile is discussed. Simple but general rules predict these shapes. An original adsorption model is proposed that accounts for the unusual peak shapes observed when the analyte is partially dissociated in the buffer solution during its elution. 相似文献
133.
Allen Knutson 《Advances in Mathematics》2004,184(1):161-176
Let (Π,Σ) be a Coxeter system. An ordered list of elements in Σ and an element in Π determine a subword complex, as introduced in Knutson and Miller (Ann. of Math. (2) (2003), to appear). Subword complexes are demonstrated here to be homeomorphic to balls or spheres, and their Hilbert series are shown to reflect combinatorial properties of reduced expressions in Coxeter groups. Two formulae for double Grothendieck polynomials, one of which appeared in Fomin and Kirillov (Proceedings of the Sixth Conference in Formal Power Series and Algebraic Combinatorics, DIMACS, 1994, pp. 183-190), are recovered in the context of simplicial topology for subword complexes. Some open questions related to subword complexes are presented. 相似文献
134.
We develop a new joint cure rate model for longitudinal and survival data. The model allows for multiple longitudinal markers as well as a cure structure for the survival component based on the promotion time cure rate model, as described in Ibrahim et al. (Bayesian Survival Analysis, Springer, New York, 2001). Several characteristics and properties of the new model are discussed and examined. A real dataset from a melanoma clinical trial is given to demonstrate the methodology. 相似文献
135.
Chau O. Shillor M. Sofonea M. 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2004,55(1):32-47
A model for the dynamic, adhesive, frictionless contact
between a viscoelastic body and a deformable foundation is
described. The adhesion process is modeled by a bonding field on
the contact surface. The contact is described by a modified normal
compliance condition. The tangential shear due to the bonding
field is included. The problem is formulated as a coupled system
of a variational equality for the displacements and a differential
equation for the bonding field. The existence of a unique weak
solution for the problem is established, together with a partial
regularity result. The existence proof proceeds by construction of
an appropriate mapping which is shown to be a contraction on a
Hilbert space. 相似文献
136.
J. Adámek 《Algebra Universalis》2004,51(2-3):215-234
A simple, direct proof of the following characterization of varieties of (finitary)
algebras is presented: a cocomplete category is equivalent to a variety iff it has an algebraic
generator, i.e., a regular generator which is exactly projective and finitely generated. This
improves somewhat a recent restatement, due to Pedicchio and Wood, of the classical
characterization theorem of Lawvere. A bijective correspondence between algebraic theories
and algebraic generators is established. 相似文献
137.
138.
A. Borelli C. O. Horgan M. C. Patria 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2003,54(5):797-806
This paper is concerned with investigation of the
influence of pre-stress and pre-polarization on the decay of
Saint-Venant end effects in piezoelectric solids. This issue is
examined within the framework of incremental anti-plane shear
states for prestressed and prepolarized solids. Attention is
confined to a specific class of materials, namely those of
hexagonal 6mm or 4mm symmetry. It is shown that the mechanical
and electrical fields uncouple in this case, and the governing
system of coupled second-order linear partial differential
equations uncouple to a single homogeneous second-order equation
with constant coefficients for the displacement and a Poisson
equation for the electric potential. The exact decay rate for
mechanical and electrical end effects is determined and the
influence of pre-stress and pre-polarization is assessed.
Motivation for this work arises from the current rapid
developments in smart materials technology. 相似文献
139.
一类三元线性分组码的译码 总被引:1,自引:0,他引:1
Pless[1]证明了三元(12,6,6)Golay码具有一种双层结构,并据此给出了该码的快速硬判决译码算法。本文推广了Golay码的Pless结构,给出了由三元(n,k,d)线性分组码构造的三元(3,n+k,≥min(n,2d,6))线性分组码,其中包括(12,6,6)Golay码和(18,9,6)码,并以三元(18,9,6)码为例给出了这类码的最大似然软判决译码算法。 相似文献
140.
Summary.
We consider a discontinuous Galerkin finite element method
applied in time to a model Volterra equation of the second kind.
A residual-based computable
Galerkin-error estimate is derived
for .
This estimate does not explicitly
contain the time step and therefore the time step
control must be based
on a heuristic criterion, the estimate can then be used to
demonstrate the integrity, or otherwise, of the finite element
solution. After performing some numerical experiments
we conclude that this approach is at least competetive
with classical discretizations since it is
computationally simple to implement,
but has the added advantage of
reliable error feedback.
Received June 25, 1995 相似文献