共查询到20条相似文献,搜索用时 46 毫秒
1.
G. K. Elyashevich I. S. Kuryndin M. A. Smirnov N. V. Bobrova 《Mechanics of Composite Materials》2006,42(6):577-586
Two types of new electroactive composite systems based on elastic substrates (porous polyethylene films) have been elaborated.
The systems of the first type are composed of electroconductive polymers (polypyrrole and polyaniline) obtained by in situ
oxidative polymerization of their monomers on porous polyethylene substrates. The composites of the second type contain a
cross-linked polyelectrolyte, and they were prepared by polymerization of acrylic acid with a macromolecular cross-linker
on the porous substrates. The mechanical properties and the deformational behavior of the porous films and composites have
been investigated and analyzed.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 42, No. 6, pp. 825–838, November–December, 2006. 相似文献
2.
Two polyester-based polymer concretes with various volume content of diabase as an extender and aggregate are tested in creep
under compression at different stress levels. The phenomenological and structural approaches are both used to analyze the
experimental data. Common features of changes in the instantaneous and creep compliances are clarified, and a phenomenological
creep model which accounts for the changes in the instantaneous compliance and in the retardation spectrum depending on the
stress level is developed. It is shown that the model can be used to describe the experimental results of stress relaxation
and creep under repeated loading. Modeling of the composite structure and subsequent solution of the optimization problem
confirm the possibility of the existence of an interphase layer more compliant than the binder. A direct correlation between
the interphase volume content and the instantaneous compliance of the composite is revealed. It is found that the distinction
in nonlinearity of the viscoelastic behavior of the two polymer concretes under investigation can be due to the difference
in their porosity.
Submitted to the 11th International Conference on Mechanics of Composite Materials (Riga, June 11–15, 2000.)
Translated from Mekhanika Kompozitnykh Materialov, Vol. 36, No. 2, pp. 147–164, 2000. 相似文献
3.
L. E. T. Ferreira 《Mechanics of Composite Materials》2007,43(5):479-486
This paper addresses the use of R-curves to study the fracture behavior of high-strength concrete and steel-fiber-reinforced
concrete subjected to crack ing in a three-point bending configuration. The R-curves are modeled through an effective approach
based on the equations of linear-elastic fracture mechanics (LEFM), which relates the applied load to the fundamental displacements
of notched-through beams loaded monotonically. It is initially shown that, for quasi-brittle materials, the R-curves responses
can be evaluated in a quasi-analytical way, using the load-crack mouth opening, the load-load line displacement, or exclusively
the displacement responses obtained experimentally. Afterward, the methodology is used to obtain the fracture responses of
high-strength and fiber-reinforced concretes, up to the final stages of rupture.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 43, No. 5, pp. 701–710, September–October, 2007. 相似文献
4.
I. Kulikov 《Lithuanian Mathematical Journal》1994,34(3):253-261
In this article algebraic formulae for compositions of the linearly limited functions in abstract rings are proved. The proofs
are based on the method of mathematical induction and can be generalized for other algebraic systems.
Rostov University, Rostov-at-Don, Russia. Published in Lietuvos Matematikos Rinkinys, Vol. 34, No. 3, pp. 320–330, July–September,
1994. 相似文献
5.
V. V. Zuev 《Mechanics of Composite Materials》2012,47(6):603-608
The effect of C60 fullerene on the mechanical properties of epoxy resins has been investigated. It is found that this filler affects the tensile
modulus and tensile strength of epoxy compositions only slightly, but their impact strength at a 0.01–0.12 wt.% content of
C60 increases by about 100–200%. A molecular mechanism of the toughening effect of C60 on epoxy resins is suggested. 相似文献
6.
Yu. V. Yakubovich 《Journal of Mathematical Sciences》2005,131(2):5569-5577
We consider the slicing of Young diagrams into slices associated with summands that have equal multiplicities. It is shown
that for the uniform measure on all partitions of an integer n, as well as for the uniform measure on partitions of an integer
n into m summands with m ∼ Anα, α ≤ 1/2, all slices after rescaling concentrate around their limit shapes. The similar problem is solved for compositions
of an integer n into m summands. These results explain why the limit shapes of partitions and compositions coincide in the
case α < 1/2. Bibliography: 10 titles.
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Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 307, 2004, pp. 266–280. 相似文献
7.
V. Kalkis R. D. Maksimov M. Kalnins J. Zicans T. Bocoka O. Revjakin 《Mechanics of Composite Materials》2000,36(3):223-232
Gamma-irradiated blends of polyethylene (PE) with ethylene-propylene-diene copolymer (EPDM) and a thermotropic liquid-crystalline
polymer (LCP) are investigated at absorbed radiation doses not exceeding 150 kGy (10 kGy=1 Mrad). The temperature dependences
of elastic moduli, tension diagrams at a temperature above the melting point of the crystalline phase of PE, and long-term
strain recovery curves for oriented test specimens are presented. The kinetics of thermal relaxation and shrinkage stresses
in previously oriented composite specimens upon their heating and cooling is investigated. Data on the influence of LCP additions
on the adhesive interaction of the compositions with steel are obtained. The peculiarities of thermomechanical and adhesion
properties of these composites are discussed taking into account the morphologic and calorimetric data obtained.
Translated from Mekhanika Kompozitnykh Materialov, Vol. 36, No. 3, pp. 379–394, May–June, 2000. 相似文献
8.
R. D. Maksimov S. Gaidukovs J. Zicans M. Kalnins E. Plume V. Spacek P. Sviglerova 《Mechanics of Composite Materials》2006,42(3):263-272
The preparation of polymer nanocomposites by mixing a solution of a styrene-acrylate copolymer with a suspension of organically
modified montmorillonite in dimethyl formamide is described. Seven different compositions with organomontmorillonite content
from 0 to 7 wt.% were prepared and tested. Results of their X-ray diffraction analysis are presented. Data on the influence
of organomontmorillonite content on the tensile stress-strain curves, elastic modulus, strength, and ultimate elongation of
the nanocomposites are obtained. The concentration dependences of elastic properties of materials with differently oriented
platelike nanoparticles is analyzed by using an algorithm elaborated for stepwise calculations of elastic constants with account
of the features of structural hierarchy of intercalated and exfoliated nanocomposites.
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Translated from Mekhanika Kompozitnykh Materialov, Vol. 42, No. 3, pp. 375–388, May–June, 2006. 相似文献
9.
V. D. Koshmanenko 《Ukrainian Mathematical Journal》2007,59(6):841-857
We establish the conditions of reconstruction of pure spectral types (pure point, pure absolutely continuous, or pure singularly
continuous spectra) in the limiting distributions of dynamical systems with compositions of alternative conflict. In particular,
it is shown that the point spectrum can be reconstructed starting from the states with pure singularly continuous spectra.
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Translated from Ukrains’kyi Matematychnyi Zhurnal, Vol. 59, No. 6, pp. 771–784, June, 2007. 相似文献
10.
The tensile strength and the fracture properties of advanced SiC-based fibers were characterized, and an extensive fractographic
analysis was conducted to correlate their mechanical behavior and microstructure. Tensile tests re vealed that the strength
of Hi-Nicalon™ and Hi-Nicalon™ Type S fibers was sensitive to a critical flaw. The inspection of fracture surfaces revealed
that the fracture of these fibers originated mainly at the critical flaw, which was surrounded by an obvious mirror zone.
The Tyranno™-SA fiber showed a transcrystalline fracture behavior. The different fracture behavior observed in this work could
be related to different fabrication processes and compositions at the grain boundary. For the Hi-Nicalon™ and Hi-Nicalon™
Type S fibers, the critical flaw size was linearly related to the mirror size. By using the linear fracture mechanics, the
fracture toughness and the critical fracture energy of the fibers were estimated.
Russian translation published in Mekhanika Kompozitnykh Materialov, Vol. 42, No. 6, pp. 759–770, November–December, 2006. 相似文献
11.
LinFanMAO YanPeiLIU FengTIAN 《数学学报(英文版)》2005,21(2):225-236
A graph is called a semi-regular graph if its automorphism group action on its ordered pair of adjacent vertices is semi-regular. In this paper, a necessary and sufficient condition for an automorphism of the graph F to be an automorphism of a map with the underlying graph F is obtained. Using this result, all orientation-preserving automorphisms of maps on surfaces (orientable and non-orientable) or just orientable surfaces with a given underlying semi-regular graph F are determined. Formulas for the numbers of non-equivalent embeddings of this kind of graphs on surfaces (orientable, non-orientable or both) are established, and especially, the non-equivalent embeddings of circulant graphs of a prime order on orientable, non-orientable and general surfaces are enumerated. 相似文献
12.
György Elekes 《Combinatorica》1998,18(1):13-25
R with few compositions and/or small image sets. Here the fine structure of such sets of mappings will be described in terms
of generalized arithmetic and geometric progressions, yielding Freiman–Ruzsa type results for a non-Abelian group.
Received: November 28, 1996 相似文献
13.
De Ming ZHU Ying SUN 《数学学报(英文版)》2007,23(8):1495-1504
In this paper, we study the dynamical behavior for a 4-dimensional reversible system near its heteroclinic loop connecting a saddle-focus and a saddle. The existence of infinitely many reversible 1-homoclinic orbits to the saddle and 2-homoclinic orbits to the saddle-focus is shown. And it is also proved that, corresponding to each 1-homoclinic (resp. 2-homoclinic) orbit F, there is a spiral segment such that the associated orbits starting from the segment are all reversible 1-periodic (resp. 2-periodic) and accumulate onto F. Moreover, each 2-homoclinic orbit may be also accumulated by a sequence of reversible 4-homoclinic orbits. 相似文献
14.
By using the linear independent fundamental solutions of the linear variational equation
along the heteroclinic loop to establish a suitable local coordinate system in some small tubular neighborhood
of the heteroclinic loop, the Poincaré map is constructed to study the bifurcation problems of
a fine 3–point loop in higher dimensional space. Under some transversal conditions and the non–twisted
condition, the existence, coexistence and incoexistence of 2–point–loop, 1–homoclinic orbit, simple 1–periodic orbit and 2–fold
1–periodic orbit, and the number of 1–periodic orbits are studied. Moreover,
the bifurcation surfaces and existence regions are given. Lastly, the above bifurcation results are applied
to a planar system and an inside stability criterion is obtained.
This work is supported by the National Natural Science Foundation of China (10371040), the Shanghai Priority
Academic Disciplines and the Scientific Research Foundation of Linyi Teacher’s University 相似文献
15.
The bijection between composition structures and random closed subsets of the unit interval implies that the composition structures
associated with S ⋂ [0, 1] for a self-similar random set S ⊂ ℝ+ are those that are consistent with respect to a simple truncation operation. Using the standard coding of compositions by
finite strings of binary digits starting with a 1, the random composition of n is defined by the first n terms of a random
binary sequence of infinite length. The locations of 1’s in the sequence are the positions visited by an increasing time-homogeneous
Markov chain on the positive integers if and only if S = exp(−W) for some stationary regenerative random subset W of the real line. Complementing our study presented in previous papers,
we identify self-similar Markov composition structures associated with the two-parameter family of partition structures. Bibliography:
19 titles.
Published in Zapiski Nauchnykh Seminarov POMI, Vol. 326, 2005, pp. 59–84. 相似文献
16.
Alain Miranville Arnaud Rougirel 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2006,57(2):244-268
We consider the Cahn–Hilliard–Gurtin equation which corresponds, in the isotropic case, to the viscous Cahn–Hilliard equation.
The convergence of its solutions toward some steady state is investigated by means of a proper generalization of the Lojasiewicz–Simon
Theorem to nongradient-like flows. Furthermore, when the anisotropic coefficients are small, we prove that these steady states
can be approximated by the corresponding stationary solutions of the viscous Cahn–Hilliard equation provided that the latter
are local minimizers of the Ginzburg–Landau free energy.
Received: April 26, 2004; revised: February 24, 2005 相似文献
17.
Hong Jun LI 《数学学报(英文版)》2006,22(4):971-988
Volume-preserving field X on a 3-manifold is the one that satisfies LxΩ = 0 for some volume Ω. The Reeb vector field of a contact form is of volume-preserving, but not conversely. On the basis of Geiges-Gonzalo's parallelization results, we obtain a volume-preserving sphere, which is a triple of everywhere linearly independent vector fields such that all their linear combinations with constant coefficients are volume-preserving fields. From many aspects, we discuss the distinction between volume-preserving fields and Reeb-like fields. We establish a duality between volume-preserving fields and h-closed 2-forms to understand such distinction. We also give two kinds of non-Reeb-like but volume-preserving vector fields to display such distinction. 相似文献
18.
Florent Hivert Jean-Christophe Novelli Jean-Yves Thibon 《Journal of Algebraic Combinatorics》2008,28(1):65-95
We propose several constructions of commutative or cocommutative Hopf algebras based on various combinatorial structures and
investigate the relations between them. A commutative Hopf algebra of permutations is obtained by a general construction based
on graphs, and its noncommutative dual is realized in three different ways, in particular, as the Grossman–Larson algebra
of heap-ordered trees. Extensions to endofunctions, parking functions, set compositions, set partitions, planar binary trees,
and rooted forests are discussed. Finally, we introduce one-parameter families interpolating between different structures
constructed on the same combinatorial objects. 相似文献
19.
Nicolás Andruskiewitsch 《Selecta Mathematica, New Series》2005,11(2):203-246
Quivers over a fixed base set form a monoidal category with tensor product given by pullback. The quantum Yang–Baxter equation,
or more properly the braid equation, is investigated in this setting. A solution of the braid equation in this category is
called a “solution” for short. Results of Etingof–Schedler–Soloviev, Lu–Yan–Zhu and Takeuchi on the set-theoretical quantum
Yang–Baxter equation are generalized to the context of quivers, with groupoids playing the role of groups. The notion of “braided
groupoid” is introduced. Braided groupoids are solutions and are characterized in terms of bijective 1-cocycles. The structure
groupoid of a non-degenerate solution is defined; it is shown that it is a braided groupoid. The reduced structure groupoid
of a non-degenerate solution is also defined. Non-degenerate solutions are classified in terms of representations of matched
pairs of groupoids. By linearization we construct star-triangular face models and realize them as modules over quasitriangular
quantum groupoids introduced in papers by M. Aguiar, S. Natale and the author. 相似文献
20.
O. V. Rusakov 《Journal of Mathematical Sciences》2011,176(2):232-238
We apply to a sequence of i.i.d. random variables a time change operator via a Poisson process that is independent of this
sequence. We consider sums of independent copies of processes constructed in this way and having continuous time. Finite limit
distributions of these sums coincide with the finite limit distributions of the Wiener–Ornstein–Uhlenbeck field that is the
tensor product of a Brownian motion and the Ornstein–Uhlenbeck process. The transition characteristics of the limit Ornstein–Uhlenbeck
process are described by Brownian bridges that are builded into the Wiener–Ornstein–Uhlenbeck field. Bibliography: 4 titles. 相似文献