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161.
162.
In the present study, an attempt has been made to model and analyze a combined footing supporting column, which is to be constructed on very soft soil. In view of small bearing capacity and very large deflections, foundations are constructed after improving the original ground. Here, the ground has been improved by providing the stone columns in the soft soil and on top of this improved ground; a granular fill layer has been placed just below the footing. The footing has been modeled as a beam having finite flexural rigidity. Granular fill layer, soft soil and stone columns have been represented by Pasternak shear layer, Kelvin–Voigt body and the Winkler springs, respectively. Nonlinear behavior of these has been considered by means of hyperbolic constitutive relationships. Governing differential equations for response of the system have been derived and presented in non-dimensional form. These equations have been solved using appropriate boundary conditions by means of an iterative Gauss Elimination technique. 相似文献
163.
Estefanía Peña 《Journal of the mechanics and physics of solids》2011,59(9):1808-1822
Deformation induced softening is an inelastic phenomenon frequently accompanying mechanical response of soft biological tissues. Inelastic phenomena which occur in mechanical testing of biological tissues are very likely to be associated with alterations in the internal structure of these materials.In this study, a novel structural constitutive model is formulated to describe the inelastic effects in soft biological tissues such as Mullins type behavior, damage and permanent set as a result of residual strains after unloading. Anisotropic softening is considered by evolution of internal variables governing the anisotropic properties of the material. We consider two weight factors wi (softening) and sk (discontinuous damage) as internal variables characterizing the structural state of the material. Numerical simulations of several soft tissues are used to demonstrate the performance of the model in reproducing the inelastic behavior of soft biological tissues. 相似文献
164.
The influence of systematic perturbation of input interaction parameters on thermodynamic equilibrium properties is studied employing dissipative particle dynamics (DPD) simulations. The values of both the excess pressure and the surface tension are found to be very sensitive to the values of the soft repulsion parameter between unlike DPD particles for high values of the coarse-graining level (number of water molecules per DPD particle). For the case in which a molecular surfactant is present at the interface we have determined the dependence of these properties on the values of the parameters that characterize the bonding force between polymer beads. No significant differences were found between linear and branched surfactants. 相似文献
165.
In this paper, a highly birefringent index-guiding photonic crystal fiber with low confinement loss is proposed by enlarging the central row of air holes in the structure. By employing the multipole method, properties of this structure, including the effective index, birefringence and confinement loss, are investigated. Simulation results indicate that high birefringence of 1.65 × 10−3 can be reached at the wavelength of 1.55 μm, and a low confinement loss on the order of 10−6 dB/km can be achieved at the same wavelength. Moreover, the impacts of air hole sizes on birefringence and confinement loss are also analyzed in detail. 相似文献
166.
The magnetoelastic plane strain problem of an interfacial Griffith crack between two dissimilar soft ferromagnetic elastic materials subjected to a uniform magnetostatic field is considered within the framework of linear magnetoelasticity. By making use of the Fourier integral transform technique, the mixed boundary problem is then reduced to a pair of singular integral equations of the second kind. Solutions of the singular integral equations are obtained numerically by means of a Jacobi polynomial expansion method. Effects of the magnetic field, the combinations of the magnetic properties of materials and the geometric parameters on the magnetoelastic stress intensity factors in the vicinity of crack tip are shown graphically. 相似文献
167.
Hiroyuki Ohshima 《Colloid and polymer science》2007,285(13):1411-1421
Theories of electrokinetics of soft particles, which are particles covered with an ion-penetrable surface layer of polyelectrolytes,
are reviewed. Approximate analytic expressions are given, which describe various electrokinetics of soft particles both in
dilute and concentrated suspensions, that is, electrophoretic mobility, electrical conductivity, sedimentation velocity and
potential, dynamic electrophoretic mobility, colloid vibration potential, and electrophoretic mobility under salt-free condition. 相似文献
168.
阮永红 《浙江大学学报(理学版)》2002,29(2):144-148
利用Feynman路径积分变分方法,推导了整个电声子耦合区域的量子阱中束缚极化子的基态能。对其数值结果研究表明:当量子阱的约束势达到一定值,极化子的基态能修正-△E随电声子耦合常数α的增加激剧增大,约束势导致有效电声子耦合从无约束势时的弱耦合向居间耦合或强耦合渡越。更重要的是,我们发现存在一个量子阱的临界有效宽度lz0,当lZ小于临界值时,-△E随lz变小很快增大;当lz大于临界值时,随lz变大,-△E几乎不变。 相似文献
169.
F. Cros L. Malier J.-P. Korb F. Chaput 《Journal of Sol-Gel Science and Technology》1998,13(1-3):457-460
A new experimental approach to study the porosity of hybrid organic-inorganic glasses is reported. It relies upon nuclear magnetic resonance observation of molecular guest dynamics. It is shown that in MTEOS xerogels, there exists an interconnected organic-rich network in which organic guests are trapped and can eventually diffuse. The interpore translational diffusion is strongly activated and its spatial extension gives information on the pore connectivity, whose decay is characterized by the interpore jump probability given by the theoretical model. 相似文献
170.
D.R. Mullins 《Surface science》2006,600(13):2718-2725
A dysprosium oxide thin film was deposited on Ru(0 0 0 1) by vapor depositing Dy in 2 × 10−7 torr O2 while the Ru was at 700 K. The film was ca. 5 nm thick and produced a p(1.4 × 1.4) LEED pattern relative to the Ru(0 0 0 1) substrate. The adsorption and reaction of CO and C2H4 adsorbed on Rh supported on the Dy2O3 film were studied by TPD and SXPS. The CO initially reacted with loosely bound oxygen in the substrate to produce CO2. After the loosely bound oxygen was removed, the CO adsorbed non-dissociatively in a manner similar to what is seen on Rh(1 1 1). C2H4 adsorbed on the Rh particles and underwent progressive dehydrogenation to produce H2 during TPD. The C from the C2H4 reacted with the O in Dy2O3 to produce CO. CO dissociation on the Rh particles could be promoted by treating the Dy2O3 with C2H4 before CO exposure. 相似文献