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1.
A. P. Gavrilyuk I. V. Krasnov Yu. G. Trapeznikov N. Ya. Shaparev 《Russian Physics Journal》1998,41(6):511-516
A model is considered for the interaction with plasma of an “optical membrane” formed by bichromatic intersecting laser beams.
This model is used to describe a number of effects resulting from the mechanical action of light on resonant ions in the plasma.
Krasnoyarsk Computing Center, Siberian Branch of the Russian Academy of Sciences. Translated from Izvestiya Vysshikh Uchebnykh
Zavedenii, Fizika, No. 6, pp. 9–14, June, 1998. 相似文献
2.
J. -B. Fournier 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,11(2):261-272
A phenomenological Landau elasticity for the shape, dilation, and lipid-tilt of bilayer membranes is developed. The shape
mode couples with the sum of the monolayers' tilt, while the dilation mode couples with the difference of the monolayers'
tilts. Interactions among membrane inclusions within regular arrays are discussed. Inclusions modifying the membrane thickness
and/or inducing a tilt-difference due to their convex or concave shape yield a dilation-induced attraction and a tilt-difference-induced
repulsion. The resulting interaction can stabilize 2D crystal phases, with the possible coexistence of different lattice spacings when the dilation-tilt-difference coupling is
large. Inclusions favoring crystals are those with either a long-convex or a short-concave hydrophobic core. Inclusions inducing
a local membrane curvature due to their conical shape repel one another. At short inclusions separations, a tilt comparable
with the inclusion's cone angle develops: it relaxes the membrane curvature and reduces the repulsion. At large separations
the tilt vanishes, whatever the value of the shape-tilt coupling.
Received 23 October 1998 and Received in final form 12 January 1999 相似文献
3.
A novel continuum model is proposed to describe the deformations of a planar lipid bilayer suspended across a circular pore.
The model is derived within a new theoretical framework for smectic A liquid crystals in which the usual director n , which defines the average orientation of the molecules, is not constrained to be normal to the layers. The free energy
is defined by considering the elastic splay of the director, the bending and compression of the lipid bilayer, the cost of
tilting the director with respect to the layer normal, the surface tension, and the weak anchoring of the director. Variational
methods are used to derive the equilibrium equations and boundary conditions. The resulting boundary value problem is then
solved numerically to compute the fully nonlinear displacement of the layers and tilt of the lipid molecules. A parametric
study shows that an increase in surface tension produces a decrease in the deformation of the lipid bilayers while an opposite
effect is obtained when increasing the anchoring strength. 相似文献
4.
Inhomogeneities in membranes give rise to localized interactions at the interface between domains in two-component vesicles.
The corresponding energy is expressed as a line tension between the two phases. In this paper we study the implications of
the thickness mismatch between domains which has been experimentally reported to be of order 20-30% and the conditions under
which the induced line tension can destabilize the domains in inhomogeneous vesicles. For asymmetric lipidic membranes we
prove an increase of the line tension and the existence of a contact angle. Adsorption of impurities is also examined, our
scope being the extension of the Canham-Helfrich model to describe elastic deformations and chemical interactions arising
at microscopic scales. This mismatch effect may have important consequences for the stability of very small domains. 相似文献
5.
6.
N. Chatzidai A. Giannousakis Y. Dimakopoulos J. Tsamopoulos 《Journal of computational physics》2009,228(6):1980-2011
We present an improved method to generate a sequence of structured meshes even when the physical domain contains deforming inclusions. This method belongs to the class of Arbitrary Lagrangian–Eulerian (ALE) methods for solving moving boundary problems. Its tools are either (a) separate mappings of the domain boundaries and enforcing the node distribution on lines emanating from singular points or (b) domain decomposition and separate mappings of each subdomain using suitable coordinate systems. The latter is shown to be more versatile and general. In both cases a set of elliptic equations is used to generate the grid extending in this way the method advanced by Dimakopoulos and Tsamopoulos [Y. Dimakopoulos, J.A. Tsamopoulos, A quasi-elliptic transformation for moving boundary problems with large anisotropic deformations, J. Comput. Phys. 192 (2003) 494–522]. We shall present examples where this earlier method and all other mesh generating methods which are based on a conformal mapping or solving a quasi-elliptic set of PDEs fail to produce an acceptable mesh and accurate solutions in such geometries. Furthermore, in contrast to other methods, appropriate boundary conditions and constraints such as, orthogonality of specific mesh lines and prespecified node distributions on them, can be easily implemented along a specific part of the domain or its boundary. Hence, no attractive terms at specific corners or singular points are needed. To increase the mesh resolution around the moving interfaces while keeping low the memory requirements and the computational time, a local mesh refinement technique has been incorporated as well. The method is demonstrated in two challenging examples where no remeshing is required in spite of the large domain deformations. In the first one, the transient growth of two bubbles embedded in a viscoelastic filament undergoing stretching in the axial direction is examined, while in the second one the linear and non-linear dynamics of two bubbles in a viscous medium are determined in an acoustic field. The large elasticity of the filament in the first case or the large inertia in the second case coupled with the externally induced large deformations of the liquid domain requires the accurate calculation which is achieved by the method we propose herein. The governing equations are solved using the finite element/Galerkin method with appropriate modifications to solve the hyperbolic constitutive equation of a viscoelastic fluid. These are coupled with an implicit Euler method for time integration or with Arnoldi’s algorithm for normal mode analysis. 相似文献
7.
The recoilless fraction is calculated for a number of Mössbauer atoms that are natural constituents of HfC, TaC, NdSb, FeO, NiO, EuO, EuS, EuSe, EuTe, SnTe, PbTe and CsF. The calculations are based on a model developed by Kagan and Maslow for binary compounds with rocksalt structure. With the exception of SnTe and, to a lesser extent, PbTe, the results are in reasonable agreement with the available experimental data and values derived from other models. 相似文献
8.
Campelo F Cruz A Pérez-Gil J Vázquez L Hernández-Machado A 《The European physical journal. E, Soft matter》2012,35(6):49-8
Phase-separated domains exist in multicomponent lipid monolayers and bilayers. We present here a phase-field model that takes into account the competition between lipid dipole-dipole interactions and line tension to define the domain morphology. A dynamic equation for the phase-field is solved numerically showing stationary non-circular shapes like starfish shapes. This phase-field model could be applied to study the dynamic properties of complex problems like phase segregation in pulmonary surfactant membranes and films. 相似文献
9.
Properties of the real part of the interaction potential between two colliding ions are studied. The calculations are performed in the framework of the energy density formalism, using the sudden approximation. In particular, we show that the potential can be written as the product of a “universal” function and of a geometrical factor. The universal function itself can be parametrized in a simple way. Connections with the proximity theorem of Randrup, Swiatecki and Tsang are discussed in detail. Comparisons with other available potentials are made for a typical example. 相似文献
10.
11.
Robert W. Field Richard A. Gottscho E. Miescher 《Journal of Molecular Spectroscopy》1975,58(3):394-413
No perturbation between two valence states of NO has ever been identified, although many valence-Rydberg and several Rydberg-Rydberg perturbations have been extensively studied. The first valence-valence crossing to be experimentally documented for NO is reported here and occurs between the 15N18O B2Π (v = 18) and B′2Δ (v = 1) levels. No level shifts larger than the detection limit of 0.1 cm?1 are observed at the crossings near and ; two crossings involving higher rotational levels could not be examined. Semi-empirical calculations of spin-orbit and Coriolis perturbation matrix elements indicate that although the electronic part of the interaction is large, a small vibrational factor renders the 15N18O B (v = 18) ? B′ (v = 1) perturbation unobservable. Semi-empirical estimates are given for all perturbation matrix elements of the operators and which connect states belonging to the configurations , , and . 相似文献
12.
E. G. Sheikin 《Technical Physics》2000,45(8):1019-1024
Parameters of the model atomic interaction potential are suggested to be determined by comparing the experimental and analytical values of projective ion ranges. The parameters were found for the interaction of Bi, Pb, Au, Yb, Er, Eu, Cs, Xe, Sn, Rb, Kr, Ga, and Cu ions with carbon and boron atoms. 相似文献
13.
H. W. Barz T. S. Biró B. Lukács J. Zimányi 《Zeitschrift für Physik A Hadrons and Nuclei》1983,311(4):311-315
Cross sections for production of pions, kaons and antikaons in heavy ion reactions are calculated in the framework of the hadrochemical model. For the reaction Ne on NaF satisfactory agreement to the measured data is reached in a wide range of energies. The importance of consecutive hadron-hadron collisions for the mass dependence is shown. 相似文献
14.
We show that the formation of membrane tubes (or membrane tethers), which is a crucial step in many biological processes, is highly nontrivial and involves first-order shape transitions. The force exerted by an emerging tube is a nonmonotonic function of its length. We point out that tubes attract each other, which eventually leads to their coalescence. We also show that detached tubes behave like semiflexible filaments with a rather short persistence length. We suggest that these properties play an important role in the formation and structure of tubular organelles. 相似文献
15.
A theoretical study of the tilt effect is presented namely the dependence of the longitudinal sound absorption and velocity on the angle between the magnetic field and the propagation vector. As has been shown, the tilt effect is a strong nonadiabatic effect which does not contain the small parameter s/v. The influence of the finite electron relaxation time on the singularities of the absorption and of the sound velocity is investigated. The tilt effect proves to be well-distinguishable if the condition ωτ > 1 is satisfied. 相似文献
16.
The Landau-Migdal interaction has been used widely in analyses of the quenching of spinisospin transitions. The separable interaction, on the other hand, has been used for studies of electric giant resonances and low-lying vibrational states, and recently for those of spin-isospin polarizations. The relation between these two interactions in the spin-isospin channel is studied. Quantitative comparison of these interactions in the spin-isospin L = 1 channel shows good correspondence between the nuclear matrix elements of the two types of interactions. 相似文献
17.
Arthur Jabs 《Zeitschrift für Physik A Hadrons and Nuclei》1968,212(3):222-234
The flux of nucleons, pions, and muons in the energy range 1–1000 GeV and in atmospheric altitudes of 0–48 km has been calculated to a high degree of accuracy and without gross simplifications. Thus a discrepancy indicated already in 1964 byBrooke, Hayman, Kamiya andWolfendale has been firmly established. The discrepancy means, that it has proved impossible to derive the measured nucleon and muon spectra near sea-level from the measured primary nucleon spectrum unless the primary spectrum is reduced by a factor of about 2.5 or the high-energy collision models commonly used are changed. The latter would mean that the fraction of energy lost by the nucleon in a collision is passed over to the muon component to a minor extent than so far accepted, and this may be achieved in two ways: either the ratio of collision energy passed on to the electron-photon component to the energy passed on to the pion-muon component is increased in favour of the former, or about 10–20% of the collision energy are passed on to unspecified particles which do not contribute appreciably to the hard and weak components of cosmic rays. — The possibility is discussed that the missing fraction of 10–20% is spent in production of baryonantibaryon pairs. 相似文献
18.
19.
L. L. Balashova A. I. Dodonov E. S. Mashkova V. A. Molchanov 《Applied Physics A: Materials Science & Processing》1982,28(3):189-194
Energy and intensity distributions of both projectiles and recoil atoms on the plane behind the scattering center at finite distance are calculated for different projectile-to-target mass ratio and different projectile energies. The projectile energy and intensity have been found to be double-valued or three-valued functions of the distance from the collision epicenter. At the same time, the recoil energy and intensity have proved to single-valued and double-valued functions of the distance from the collision epicenter for parallel and divergent projectile fluxes, respectively. 相似文献
20.
Compositional lipid domains ("lipid rafts") in plasma membranes are believed to be important components of many cellular processes. The mechanisms by which cells regulate the sizes and lifetimes of these spatially extended domains are poorly understood at the moment. Here we show that the competition between phase separation in an immiscible lipid system and active cellular lipid transport processes naturally leads to the formation of such domains. Furthermore, we demonstrate that local interactions with immobile membrane proteins can spatially localize the rafts and lead to further clustering. 相似文献