共查询到20条相似文献,搜索用时 15 毫秒
1.
A particularly simple chaotic nonequilibrium open system with two Cartesian degrees of freedom, characterized by two distinct temperatures T(x) and T(y), is introduced. The two temperatures are maintained by Nose-Hoover canonical-ensemble thermostats. Both the equilibrium (no net heat transfer) and nonequilibrium (dissipative) Lyapunov spectra are characterized for this simple system. 相似文献
2.
Andrey Pryamikov Philippe Ben-Abdallah Jérémie Drevillon 《Journal of Quantitative Spectroscopy & Radiative Transfer》2011,112(8):1314-1322
The near field heat transfer between two finite size one-dimensional photonic crystals separated by a small vacuum gap and maintained in nonequilibrium thermal situation is theoretically investigated. The main features of this electromagnetic transfer are discussed and compared with what is generally observed with media that support surface polaritons. It is shown that the presence of surface Bloch waves can significantly enhance heat transfers beyond the far field limit for both polarization states of electromagnetic field at subwavelength separation distances. A specific attention is addressed to the consequence of the slopes of surface Bloch waves dispersion curves on the heat transfer. In particular, it is shown that the localization of surface Bloch waves close to the light line allows to observe a transfer exaltaion at larger separation distances than the Wien wavelength. These results could open new possibilities for the development of innovative near-field technologies such as near-field thermophotovoltaic conversion, plasmon assisted nanophotolitography or near-field spectroscopy. 相似文献
3.
V. Ya. Aleshkin L. V. Gavrilenko D. M. Gaponova A. M. Kadykov V. G. Lysenko Z. F. Krasil’nik 《Journal of Experimental and Theoretical Physics》2013,117(5):944-949
We experimentally observed an increase in the intensity of photoluminescence from a wider quantum well (QW) when an exciton transition was induced in the neighboring narrower QW separated from the former one by a tunneling-nontransparent AlGaAs barrier. The dependence of the efficiency of the near-field radiative transfer of excitons on the distance between QWs was studied in heterostructures without coincidence of exciton resonances in the adjacent QWs. Theoretical results were qualitatively consistent with the available experimental data. 相似文献
4.
M. S. Kurdoglyan 《Optics and Spectroscopy》2001,91(4):609-612
The problem of the resonance dipole-dipole interaction between two molecules near a spherical semiconductor nanoparticle is considered. It is shown that the presence of the nanoparticle results in the additional interaction between the molecules, which, under certain conditions, can significantly exceed the direct dipole-dipole interaction. This occurs in the case when the ground-state energy of an exciton is in a close resonance with the energies of molecular transitions. The effect of the additional interaction on the probability of intermolecular resonance energy transfer is especially important at large distances between molecules. The matrix elements of the interaction are estimated for nanoparticles of semiconductor materials CuCl and GaAs. 相似文献
5.
6.
《Physics letters. A》1986,116(5):237-240
A general nonlocal theory of heat transport in laser-plasma interaction experiments is presented. It is shown that the inverse bremsstrahlung absorption and the plasma expansion are responsible for heat fluxes qib and qh which add to the heat flux due to the temperature gradient itself. 相似文献
7.
It is shown by numerical simulation that the enhancement of the field near metallic nanoparticles is most significant in the
transparency region of the matrix material and falls off as the absorption coefficient rises. In an absorbing matrix medium
this leads both to an increase in the fraction of energy absorbed by the matrix material and to a substantial transformation
in its spectral distribution. This is illustrated for the case of copper phthalocyanine with silver nanoparticles. By choosing
the size of the introduced plasmon nanoparticles it is possible to enhance the absorption in the visible for the materials
used in solar cells and thereby increase their energy efficiency. 相似文献
8.
K.Goverdhan Reddy 《Physics letters. A》1980,78(3):277-280
The problem of the heat transfer due to a viscous incompressible flow between two infinite parallel porous disks is considered. It is assumed that the disks are rotating with moderate angular velocity. The governing equations are solved by a perturbation procedure. The results obtained reveal that the temperature distribution is more or less parabolic, approaching to a linear from as the cross flow decreases. 相似文献
9.
We propose a scheme for long-distance quantum state transfer between different atoms based on cavity-assisted interactions. In our scheme, a coherent optical pulse sequentially interacts with two distant atoms trapped in separated cavities. Through the measurement of the state of the first atom and the homodyne detection of the final output coherent light, the quantum state can be transferred into the second atom with a success probability of unity and a fidelity of unity. In addition, our scheme neither requires the high-Q cavity working in the strong coupling regime nor employs the single-photon quantum channel, which greatly relaxes the experimental requirements. 相似文献
10.
Faisal Shahzad Wasim Jamshed Tanveer Sajid Kottakkaran Sooppy Nisar Mohamed R Eid 《理论物理通讯》2021,73(7):75004
The flow of a magnetite-H_2O nanofluid has been considered among two rotating surfaces,assuming porosity in the upper plate. Furthermore, the lower surface is considered to move with variable speed to induce the forced convection. Centripetal as well as Coriolis forces impacting on the rotating fluid are likewise taken into account. Adequate conversions are employed for the transformation of the governing partial-differential equations into a group of non-dimensional ordinary-differential formulas. Numerical solution of the converted expressions is gained by means of the shooting technique. It is theoretically found that the nanofluid has less skin friction and advanced heat transport rate when compared with the base fluid. The effect of rotation causes the drag force to elevate and reduces the heat transport rate. Streamlines are portrayed to reveal the impact of injection/suction. 相似文献
11.
M.M. Al Shorman F.S. Nammas H. Haddad A.A. Shukri 《Chinese Journal of Physics (Taipei)》2018,56(3):1057-1063
The thermodynamic properties of two electrons in two dimensional parabolic GaAs quantum dot are studied where both the magnetic field and the e–e interaction are fully considered. The e–e interaction has been treated by a model potential which makes the Hamiltonian exactly solvable. The energy spectrum is used to calculate the canonical partition function, and then we obtain the thermodynamic properties; mean energy, heat capacity and entropy as a function of temperature (T) and magnetic field (B).A steep transition from zero to 4kB is observed in the heat capacity as a function of temperature for small values of magnetic field and saturates within a small temperature range, also the heat capacity has a peak-like structure at low temperature, while for high magnetic field heat capacity develops a shoulder at 2kB then it approaches the saturation value with further increase in temperature. The entropy increases with increasing temperature, but at higher temperature, it remains almost independent of the magnetic field. It is shown that, at low magnetic field values, the effect of magnetic field on heat capacity is tangible and it attains a constant value with further increase in magnetic field. Entropy is almost linearly proportional with increasing magnetic field strength. 相似文献
12.
We generalize the formalism proposed by Dalibard, Dupont-Roc, and Cohen-Tannoudji (the DDC formalism) in the fourth order for two atoms in interaction with scalar fields in vacuum to a thermal bath at finite temperature T, and then calculate the interatomic interaction energy of two ground-state atoms separately in terms of the contributions of thermal fluctuations and the radiation reaction of the atoms and analyze in detail the thermal corrections to the van der Waals and Casimir–Polder interactions. We discover a particular region, i.e. $\sqrt[4]{{\lambda }^{3}\beta }\ll L\ll \lambda $ with L, β and λ denoting the interatomic separation, the wavelength of thermal photons and the transition wavelength of the atoms respectively, where the thermal corrections remarkably render the van der Waals force, which is usually attractive, repulsive, leading to an interesting crossover phenomenon of the interatomic interaction from attractive to repulsive as the temperature increases. We also find that the thermal corrections cause significant changes to the Casimir–Polder force when the temperature is sufficiently high, resulting in an attractive force proportional to TL−3 in the λ ≪ β ≪ L region, and a force that can be either attractive or repulsive and even vanishing in the β ≪ λ ≪ L region depending on the interatomic separation. 相似文献
13.
B.U. Felderhof 《Physica A》1977,89(2):373-384
We evaluate the hydrodynamic interaction tensors for two spheres of unequal size and for general mixed slip-stick boundary conditions. A method of reflections leads to a series expansion for the diffusion tensors in powers of the inverse distance l?1 between sphere centers and explicit results are derived through terms of order l?7. It turns out that the series expansion for the diffusion tensors converges much more rapidly than that for the friction tensors. 相似文献
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15.
研究了双模真空场与两个耦合二能级原子相互作用中的和压缩.并讨论了原子的初始相干性及原子间的耦合常数对该压缩的影响. 相似文献
16.
The mechanical interaction between an electromagnetic field and a nanoscopic thin film near electronic resonance is theoretically studied by calculation of Maxwell's stress tensor. As a result of numerical demonstrations for both propagating and evanescent incident waves, the following effects that are specific to this condition have been clarified: (1) The force exerted on a nanoscopic thin film is greatly enhanced near the resonance frequency to the same order of magnitude as for a film with macroscopic thickness. (2) The peak position of the gradient force in its spectrum is highly sensitive to the change in nanoscopic thickness that is due to the polaritonic effect. (3) In a total-reflection region a large enhancement of the repulsive force between the two thin films occurs when the films act as an optical cavity. 相似文献
17.
K.H. Lau 《Solid State Communications》1980,34(5):347-348
The indirect elastic interaction between two adatoms on substrates with a very small shear modulus such as V3Si and Nb3Sn near the transformation temperature TM is calculated. As the temperature decreases towards TM, the shear moduli of these materials go to zero, and the strength of the interaction increases dramatically. The interaction is strongly attractive if the adatoms are aligned along a cube axis and repulsive if they are at 45° to the axis. 相似文献
18.
R. M. Thaokar 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,61(1):47-58
The hydrodynamic interactions between two rotating tori is studied. Two kinds of
problems are addressed. The interaction between two force free tori
is examined, for co and counter rotating cases, which should be relevant in the case of swimming of two toroidal animals and
form the basis for interaction of a swarm of such swimmers, apart from the dynamics
of a collection of stiff polymer rings. The second problem is
the case of two non-translating rotating tori, a possible configuration
in toroidal mixers for microfluidic devices. In the former case,
analytical expression for translational velocity shows good agreement with
the theory in the far field case and show a strong reduction in the
velocities in the lubrication limit for the co-rotating case. The velocities are found to monotonically reduce to zero in
the case of counter-rotating tori.
For the latter case, the
expression for velocity field is derived the net force acting
on the torus is analytically calculated. The comparison with numerical results is encouraging both in the case of co as well
as counter-rotation. The expressions derived for velocities
should be useful in estimating pseudo-potentials between such pairs. 相似文献
19.
Kiril Kolikov Dragia Ivanov Georgi Krastev Yordan Epitropov Stefan Bozhkov 《Journal of Electrostatics》2012,70(1):91-96
In the paper we consider the problem of the electrostatic interaction between two charged conducting spheres with arbitrary electrical charges and radiuses. Using the image charges method we determine exact analytical formulas for the force F and for the potential energy W of the interaction between these two spheres as well as for the potential V of the electromagnetic field in an arbitrary point created by them. Our formulas lead to Coulomb’s law for point charges.We theoretically prove the experimentally shown fact that two spheres with the same type (positive or negative) of charges can also attract each other. 相似文献
20.
An electrostatic interaction between two separate, grounded, uncharged, perfectly conducting spheres of different radii in a uniform electrostatic field is investigated. It is shown that at a small center-to-center distance of the spheres, the force of the polarization interaction between the spheres depends appreciably more weakly on that distance in comparison to the force of the electrostatic interaction of two elementary dipoles as it should be in view of the interaction between two like polarization charges. 相似文献