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991.
992.
993.
R.W. Ogden 《International Journal of Non》2009,44(5):570-580
The equations describing the interaction of an electromagnetic sensitive elastic solid with electric and magnetic fields under finite deformations are summarized, both for time-independent deformations and, in the non-relativistic approximation, time-dependent motions. The equations are given in both Eulerian and Lagrangian form, and the latter are then used to derive the equations governing incremental motions and electromagnetic fields superimposed on a configuration with a known static finite deformation and time-independent electromagnetic field. As a first application the equations are specialized to the quasimagnetostatic approximation and in this context the general equations governing time-harmonic plane-wave disturbances of an initial static configuration are derived. For a prototype model of an incompressible isotropic magnetoelastic solid a specific formula for the acoustic shear wave speed is obtained, which allows results for different relative orientations of the underlying magnetic field and the direction of wave propagation to be compared. The general equations are then used to examine two-dimensional motions, and further expressions for the wave speed are obtained for a general incompressible isotropic magnetoelastic solid. 相似文献
994.
以草酸、硝酸铁、硝酸钴为原料, 加入不同聚合度的PEG, 采用低热固相反应法制备出草酸铁和草酸钴的混合前驱物. 在不同的温度(25, 60, 70, 75 ℃), 混合前驱物分别恒温反应2 h, 然后经450 ℃灼烧. 对获得的粉体用XRD, SEM, 激光粒度仪表征后证明: 加入PEG400在75 ℃反应获得了长径比约为6~15范围, 具有立方晶系尖晶石结构的棒状CoFe2O4铁氧体粉末. 经测试电磁学性质发现, 与粒状的CoFe2O4相比, 棒状的CoFe2O4磁导率虚部在高频15~20 GHz范围增加了近1倍, 各向异性常数Ku则增加了近5倍. 预示一维棒状结构的CoFe2O4作为吸波材料具有良好应用前景. 相似文献
995.
This article presents a new methodology to estimate the effective permeability of random fractured media of any anisotropy
containing both microfractures and a large number of long fractures crosscutting the representative volume element. The fractures
are replaced by fictitious permeable materials for which the tangential permeability is deduced from a Poiseuille flow. A
self-consistent scheme is proposed to derive the macroscopic permeability. On the one hand, the contribution of long fractures
to the effective permeability writes by simple superposition of the fracture tangential permeabilities. On the other hand,
the contribution of microfractures needs to resort to auxiliary problems requiring the computation of second-order Hill (or
Eshelby) tensors related to ellipsoids embedded in an anisotropic matrix, for which a complete procedure is detailed. The
effect of the microfracture normal permeability is put in evidence in the upscaling scheme and analyzed. In particular, it
is shown that it must be chosen large enough to allow the connections between families. Examples are finally developed and
compared to numerical simulations in the 2D case. 相似文献
996.
This paper presents an alternative analytical technique to study a plane strain consolidation of a poroelastic soil by taking into account the anisotropy of permeability. From the governing equations of a saturated poroelastic soil, the relationship of basic variables for a point of a soil layer is established between the ground surface (z=0) and the depth z in the Laplace-Fourier transform domain. Combined with the boundary conditions, an exact solution is derived for plane strain Biot's consolidation of a finite soil layer with anisotropic permeability in the transform domain. Numerical inversions of the Laplace transform and the Fourier transform are adopted to obtain the actual solution in the physical domain. Numerical results of plane strain Biot's consolidation for a single soil layer show that the anisotropic of permeability has a great influence on the consolidation behavior of the soils. 相似文献
997.
脂质体毛细管电泳方法评价有机化合物在体内的吸收 总被引:1,自引:0,他引:1
有机化合物在脂质体毛细管电泳中的保留值大小可以体现化合物的亲脂性大小。比较了9种有机化合物在脂质体毛细管电泳中脂质体/水的疏水参数(log Plw)(由保留因子k的对数值(log k)转化而来)及其在正辛醇/水体系中的疏水参数(log Pow)与其渗透系数的对数值(log Pm)的相关性,log Plw与log Pm的相关系数为0.94,log Pow与log Pm的相关系数仅为0.78,说明脂质体/水模型较正辛醇/水模型更加接近于生物膜模型。脂质体毛细管电泳可以快速、准确地测定化合物的疏水参数,通过化合物在脂质体毛细管中的保留可以快速、初步地预测化合物在体内的吸收情况。 相似文献
998.
Bifurcations and route to chaos of the Mathieu–Duffing oscillator are investigated by the incremental harmonic balance (IHB)
procedure. A new scheme for selecting the initial value conditions is presented for predicting the higher order periodic solutions.
A series of period-doubling bifurcation points and the threshold value of the control parameter at the onset of chaos can
be calculated by the present procedure. A sequence of period-doubling bifurcation points of the oscillator are identified
and found to obey the universal scale law approximately. The bifurcation diagram and phase portraits obtained by the IHB method
are presented to confirm the period-doubling route-to-chaos qualitatively. It can also be noted that the phase portraits and
bifurcation points agree well with those obtained by numerical time-integration. 相似文献
999.
1000.
Exchange anisotropy in FM/AFM bilayers has given a lot of static
magnetization properties such as enhanced coercivity and
magnetization loop shifts. These phenomena are primarily from the
effective anisotropies introduced into a ferromagnet by exchange coupling with a strongly anisotropic antiferromagnet. These effective anisotropies can also be used to explain the dynamic
consequences of exchange-biased bilayers. In this article, the
dynamic consequences such as exchange-induced susceptibility,
exchange-induced permeability, and the corresponding domain wall
characteristics in the exchange-biased structures of
ferromagnet/antiferromagnet1/antiferromagnet2 are studied. The results show that the second antiferromagnetic layer can largely affect the dynamic consequences of exchange-biased bilayers. Especially in the case of critical temperature, the effects become
more obvious. Practically, the exchange anisotropy of biased bilayer system can be tuned by exchange coupling with the second antiferromagnetic layer. 相似文献