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81.
Michael Růžička 《Applications of Mathematics》2004,49(6):565-609
Many electrorheological fluids are suspensions consisting of solid particles and a carrier oil. If such a suspension is exposed to a strong electric field the effective viscosity increases dramatically. In this paper we first derive a model which captures this behaviour. For the resulting system of equations we then prove local in time existence of strong solutions for large data. For these solutions we finally derive error estimates for a fully implicit time-discretization. 相似文献
82.
83.
We consider the existence of steady incompressible fluids (solutions to the Euler equations) on Riemannian manifolds of dimensions three and higher. We demonstrate that, as in the case of the ABC fields in dimension three, there exist chaotic Beltrami fields – nonsingular eigenfields of the curl operator – in higher dimensions. We give an explicit set of analytic examples on a non-Euclidean five-torus T
5. We also detail a plug construction for inserting chaotic vortices into a Beltrami field. These constructions employ contact-topological techniques. 相似文献
84.
极性分子型电流变液 总被引:2,自引:0,他引:2
电流变液在电场作用下软硬连续可调的奇特性质具有广泛和重要的应用价值。传统电流变液是基于颗粒极化产生的相互作用,根据介电理论预测,其剪切屈服强度的上限约为10kPa。电流变液被发明50年来,阻碍其应用的主要原因是剪切强度低。近年来发明的"极性分子型电流变液"是一类新型电流变液,其屈服强度比传统电流变液大一个数量级以上,且与电场强度呈线性关系,这一点和传统电流变液中的平方关系也明显不同。文章作者提出了极性分子在颗粒间强局域电场中的取向并与极化电荷作用的模型,成功地解释了观察到的实验现象。根据这一原理,有可能制备出屈服强度高达MPa的电流变液。 相似文献
85.
A. Maeyens J. Tempere 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,58(3):231-236
We consider a superconducting material that exists in the liquid state, more
precisely, in which the Meissner-Ochsenfeld effect persists in the liquid
state. First, we investigate how the shape of such a hypothetical Meissner
liquid will adapt to accomodate for an applied external field. In particular,
we analyse the case of a droplet of Meissner fluid, and compute the elongation
of the droplet and its quadrupole frequency as a function of the applied
field. Next, the influence of an applied field on the flow of the liquid is
studied for the case of a surface wave. We derive the dispersion relation for
surface waves on an incompressible Meissner fluid. We discuss some candidate
realizations of the Meissner fluids and for the case of a superconducting
colloid discuss which regime of wave lengths would be most affected by the
Meissner effect. 相似文献
86.
P K Karmakar 《Pramana》2007,68(4):631-648
Application of inertia-induced acoustic excitation theory offers a new resonant excitation source channel of acoustic turbulence
in the transonic domain of plasma flow. In bi-ion plasmas like colloidal plasma, two well-defined transonic points exist corresponding
to the parent ion and the dust grain-associated acoustic modes. As usual, the modified ion acoustic mode (also known as dust
ion-acoustic (DIA) wave) dynamics associated with parent ion inertia is excitable for both nanoscale-and micronscale-sized
dust grains. It is found that the so-called (ion) acoustic mode (also known as dust-acoustic (DA) wave) associated with nanoscale
dust grain inertia is indeed resonantly excitable through the active role of weak but finite parent ion inertia. It is interestingly
conjectured that the same excitation physics, as in the case of normal plasma sound mode, operates through the active inertial
role of plasma thermal species. Details of the nonlinear acoustic mode analyses of current interest in transonic domains of
such impure plasmas in hydrodynamic flow are presented.
相似文献
87.
《Comptes Rendus Physique》2013,14(6):447-450
One of the major emerging fields of research of the beginning of this century concerns living fluids. By “living fluids”, we mean two major categories of complex fluids: (i) fluids which are essential to life, like blood, and (ii) active fluids made of particles that are able to propel themselves in the suspending fluid by converting a form of their energy into mechanical motion. Studies on active fluids have known a considerable interest since the last decade. Blood might be viewed as an old topic, but the progresses in experimental techniques, analytical concepts and numerics, have contributed nowadays to a dramatic renewal of the interest in this field, with a great potential towards understanding physical and mechanical factors in cardiovascular diseases. These fields have considerably strengthened interdisciplinary research. The series of reviews of this dossier focus on the tremendous recent progress achieved in research on living fluids both from the experimental and theoretical points of views. These reviews present also the major open issues, making of this dossier a unique guide for future research in these fields. This project grew up thanks to the international summer school that we organized on the topic “living fluids” at the IES (Institut dʼétudes scientifiques) of Cargèse (Corsica) in 2012. 相似文献
88.
Y. Paul Handa Zhiyi Zhang Jacques Roovers 《Journal of Polymer Science.Polymer Physics》2001,39(13):1505-1512
tert‐Butyl‐substituted poly(ether ether ketone) (tBuPEEK), which does not undergo crystallization with thermal annealing, crystallizes readily when treated with compressed CO2. The dissolved CO2 causes a reduction in the glass‐transition temperature of the polymer–gas system and enhances the chain mobility of the macromolecules, thereby bringing about crystallization. In the presence of CO2, crystallization is increasingly favored with increasing CO2 pressure and treatment temperature. The melting point of tBuPEEK crystals increases linearly with the CO2 pressure applied in the treatment, indicating an increase in the order and/or size of the crystals. The extent of crystallinity increases when small amounts of methanol or dichloromethane are used as a cosolute with CO2. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1505–1512, 2001 相似文献
89.
We give a simplified proof of the linear instability of equilibrium figures of rotating liquid based on energy estimates.
相似文献
90.
Gunjan Verma V. K. Aswal S. K. Kulshreshtha C. Manohar P. A. Hassan Eric W. Kaler 《Pramana》2008,71(5):997-1002
Structural parameters of micelles formed by Triton X-100 in the presence of solubilized anthranilic acid at different pH values
was investigated using light scattering and small angle neutron scattering. Analysis of the SANS data indicate that micelles
are oblate ellipsoidal in nature with little variation in the dimensions, in the investigated pH range (from 0.5 to 6.0).
The interaction potential of the micelles shows a minimum closer to the isoelectric point of anthranilic acid. A similar variation
is observed in the cloud point of the micelles with pH. The observed variation in the interaction potential with pH of the
micellar solution can be explained in terms of the reversal of charge on anthranilic acid due to shift in the acid-base equilibrium.
The variation in interaction potential and cloud point with pH is modelled using Coulombic repulsion of charged molecules
at the micelle interface.
相似文献