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41.
Klaus Aehlig 《Annals of Pure and Applied Logic》2010,161(6):711-736
Using appropriate notation systems for proofs, cut-reduction can often be rendered feasible on these notations. Explicit bounds can be given. Developing a suitable notation system for Bounded Arithmetic, and applying these bounds, all the known results on definable functions of certain such theories can be reobtained in a uniform way. 相似文献
42.
43.
A novel state-space form for studying transverse vibrations of double-beam systems, made of two outer elastic beams continuously joined by an inner viscoelastic layer, is presented and numerically validated. As opposite to other methods available in the literature, the proposed technique enables one to consider (i) inhomogeneous systems, (ii) any boundary conditions and (iii) rate-dependent constitutive law for the inner layer. The formulation is developed by means of Galerkin-type approximations for the fields of transverse displacements in the system. Numerical examples demonstrate that the proposed approach is accurate and versatile, and lends itself to be used for both frequency- and time-domain analyses. 相似文献
44.
Despite possessing excellent specific properties, rapid corrosion of magnesium is a significant barrier in its widespread use. Alloying Mg to enhance mechanical properties nominally increases susceptibility to corrosion from microstructural heterogeneity. Furthermore, alloying Mg nominally accelerates cathodic kinetics and hence also accelerates corrosion. To date, no alloying additions to Mg suggest that a reduction in corrosion rate can be imparted, however we reveal for the first time that alloying additions of arsenic can impart significant corrosion resistance to Mg via retarding the cathodic reaction. 相似文献
45.
This paper defines and examines the basic properties of non-commutative analogues of almost complex structures, integrable almost complex structures, holomorphic curvature, cohomology, and holomorphic sheaves. The starting point is a differential structure on a non-commutative algebra defined in terms of a differential graded algebra. This is compared to current ideas on non-commutative algebraic geometry. 相似文献
46.
On the local fractional derivative 总被引:1,自引:0,他引:1
We present the necessary conditions for the existence of the Kolwankar-Gangal local fractional derivatives (KG-LFD) and introduce more general but weaker notions of LFDs by using limits of certain integral averages of the difference-quotient. By applying classical results due to Stein and Zygmund (1965) [16] we show that the KG-LFD is almost everywhere zero in any given intervals. We generalize some of our results to higher dimensional cases and use integral approximation formulas obtained to design numerical schemes for detecting fractional dimensional edges in signal processing. 相似文献
47.
Lyes Nechak Sébastien Berger Evelyne Aubry 《European Journal of Mechanics - A/Solids》2011,30(4):594-607
This paper presents a dynamic behaviour study of non-linear friction systems subject to uncertain friction laws. The main aspects are the analysis of the stability and the associated non-linear amplitude around the steady-state equilibrium. As friction systems are highly sensitive to the dispersion of friction laws, it is necessary to take into account the uncertainty of the friction coefficient to obtain stability intervals and to estimate the extreme magnitudes of oscillations. Intrusive and non-intrusive methods based on the polynomial chaos theory are proposed to tackle these problems. The efficiency of these methods is investigated in a two degree of freedom system representing a drum brake system. The proposed methods prove to be interesting alternatives to the classic methods such as parametric studies and Monte Carlo based techniques. 相似文献
48.
Donald Hill Peter J. Holliman Eurig W. Jones James McGettrick David A. Worsley Marco Appleman Pranesh Chatterjee 《Surface and interface analysis : SIA》2019,51(9):934-942
This paper studies the removal of chemisorbed carboxylates and phosphonates from TiO2-coated galvanized steel using NaOH(aq). XPS and FTIR data show that NaOH(aq) is effective at desorbing these species and so is an alternative to gas phase processes (eg, plasma cleaning). Tribological investigations show that NaOH(aq)-treated surfaces show reduced friction and wear, relative to the “as-received” galvanized steel. This is ascribed to carbonate (present as an impurity in NaOH) that adsorbs to the surface of the substrate during NaOH(aq) immersion. Carbonate removal through sonication in water generates surfaces that show friction similar to “as-received” galvanized steel. This work is useful in areas (eg, automotive manufacturing), where the effective removal of lubricants following tribological contact is key to subsequent paint adhesion. 相似文献
49.
Wentao Fan Farzad Fathizadeh Matilde Marcolli 《Letters in Mathematical Physics》2018,108(12):2729-2747
We show that, when considering the anisotropic scaling factors and their derivatives as affine variables, the coefficients of the heat-kernel expansion of the Dirac–Laplacian on SU(2) Bianchi IX metrics are algebro-geometric periods of motives of complements in affine spaces of unions of quadrics and hyperplanes. We show that the motives are mixed Tate and we provide an explicit computation of their Grothendieck classes. 相似文献
50.
The axisymmetric deformations of thick circular rings are investigated. Four materials are explored: linear material, incompressible Neo-Hookean material and Ogden's and Bower's forms of compressible Neo-Hookean material. Radial distributed forces and a displacement-dependent pressure are the external loads. This problem is relatively simple and allows analytical, or semi-analytical, solution; therefore it has been chosen as a benchmark to test commercial finite element software for various material laws at large strains. The solutions obtained with commercial finite element software are almost identical to the present semi-analytical ones, except for the linear material, for which commercial finite element programs give incorrect results. 相似文献