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1.
The flow of drops suspended on an inclined surface, are studied by numerical simulations at finite Reynolds numbers. The flow is driven by the acceleration due to gravity, and there is no pressure gradient in the flow direction. The effect of the Reynolds number, the Capillary number and density ratio on the distribution of drops and the fluctuation energy across the channel are investigated. It is found that drops tend to stay away from the channel floor, which is consistent with the behavior observed in the granular flow regime. Drops that are less deformable will stay further away from the channel floor. Also, drops appear at a larger distance from the floor as the Reynolds number increases. Simulations at large density ratios show that results are more compatible with computer simulations of granular flows. The behavior observed here resembles more the granular flow regime when the restitution coefficient is low. 相似文献
2.
It is shown that during a capillary discharge, plasma channels for guiding light from high-power lasers are temporarily formed.
The experiments are performed with alumina capillaries of 2-mm radius and 14-cm length filled with about 100 Pa of helium,
methane or hydrogen. The transmission of probe light is enhanced due to light guiding by a factor up to 20 during a time window
of 5 ns. The results indicate the formation of a first channel, when the shock wave reaches the axis, and of a second channel
after the reflection of the shock wave on the axis. Compared to simple focussing by a lens, in the guiding device the intensity–length
product increases by almost two orders of magnitude. Guiding is achieved over 180 times the Rayleigh length.
Received: 20 June 2000 / Revised version: 4 August 2000 / Published online: 6 September 2000 相似文献
3.
We consider the irreversible dynamics of two two-level atoms that interact with a bipartite broad-band electromagnetic field
in an entangled state that forms a heat bath with a quantum correlation. Using Ito’s stochastic integration technique, we
have derived a kinetic equation for atoms and found their steady state, which turns out to be inseparable and leads to a violation
of Bell’s inequalities. The application of the atomic state found as a quantum channel for teleportation is considered. We
have calculated the channel quality or fidelity that determines the possibilities for using the channel, in particular, characterizes
its security. The process of teleportation by means of a quantum channel formed by an entangled heat bath is considered. Comparison
of two (atomic and light) channels has shown that they have different properties with regard to separability and identical
properties with regard to nonlocality. This means that nonlocality can be completely transferred from light to atoms. 相似文献
4.
L. N. Oveshnikov A. B. Davydov V. A. Kulbachinskii B. A. Aronzon 《Bulletin of the Lebedev Physics Institute》2017,44(5):143-146
Heterostructures with a GaAs/InGaAs/GaAs quantum well and aMn magnetic impurity layer separated from it, which have different conductivity types, are studied. At a Mn content not exceeding the amount corresponding to 0.5 monolayer of MnAs, a percolation cluster formed in the quantum well plane is not simply connected, but consists of metal drops separated by low-conductivity interspaces. Despite the absence of the simply connected conducting channel, Shubnikov–de Haas oscillations are observed in all studied systems, which are controlled by carrier properties in conducting drops, independent of Mn content. The estimate of drop sizes corresponds to theoretical values. 相似文献
5.
The use of an interference microscope in the assessment of channel waveguides formed by ion exchange in glass is presented. In the particular mode of operation discussed, light is passed through the guide parallel to the surface normal to yield the lateral index profile. It is shown that the surface expansion of the glass that occurs during the exchange has a significant effect on the interference data. A simple method of correcting for this effect is reported and justified. The application of the above technique to the characterisation of Cu ion exchanged channel guides is demonstrated. Some observations concerning the relationship between the index profile and surface expansion profile are made. 相似文献
6.
Popov S.A. Proskurovsky D.I. Batrakov A.V. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1999,27(4):851-857
The velocity spectrum of drops emitted by a liquid-metal explosive-emission cathode has been investigated. A relation between the sizes of the drops and their maximum velocities has been found for the velocity range 103-8×104 cm/s. The relation obtained supports the earlier established mechanism for the emission of drops under the action of high pressures developing in explosive emission centers. The possibilities of an additional acceleration of drops due to the explosion of necks formed on breaking the drops off the cathode surface and at the expense of the kinetic energy of the ions of the expanding cathode plasma have been discussed 相似文献
7.
V. A. Loiko A. V. Konkolovich V. Ya. Zyryanov A. A. Miskevich 《Optics and Spectroscopy》2017,122(6):984-994
An optico-mechanical model describing the coherent (directed) transmittance and the degree of polarization of forward-transmitted light by a polymer film with elongated liquid-crystal (LC) drops has been developed. This model, based on the Foldy–Twersky and anomalous-diffraction approximations, makes it possible to analyze the optical response of a film under extension as a function of the film thickness, refractive index of the polymer, the sizes and anisometry parameters of liquid-crystal drops, their concentration, internal structure, polydispersity, and orientation of optical axes. The model is verified based on the comparison of numerical and experimental data for the inverse modification of interfacial anchoring by an ion-forming surfactant. The internal drop structure is determined by solving the problem of minimizing the volume free energy density. A comparative analysis of the calculated transmittance and degree of polarization for films with uniform homeotropic and modified inhomogeneous interfacial anchoring is performed. The spectral polarization characteristics of a film with elongated LC drops and single-domain internal structure, formed under mechanical extension with the aid of surfactants, are investigated. 相似文献
8.
Two-mode generation of light in a system of N identical relaxation-free atoms placed in a resonator is considered on the basis of the derived controlling Fokker-Planck equation for the Glauber-Sudarshan quasiprobability. Under steady-state conditions, a state of modes is formed with nonclassical correlation characterized by sub-Poison statistics of photons and leading to complete suppression of shot noise. Being an entangled pair, these sub-Poisson modes can be used as a quantum channel for teletransmission of light. In contrast to the standard Einstein-Podolskly-Rosen (EPR) channel, the recipient can reproduce only correlation functions of the intensity of an unknown state. 相似文献
9.
The Letter shows that inside a dropwise cluster formed over the heated water surface, water drops are electrically charged. The charge of a separate drop reaches 103 units of an elementary charge. The drops are positioned from each other at the distance of double Debye radius length. It is fixed up that drops levitate over the water surface in consequence of the Stokes force acting from the side of gas-vapor flow rising from water surface. The Stokes force thousand times exceeds the Coulomb drop repulsion force from the water surface. 相似文献
10.
When a current is applied to a type-I superconducting strip containing a narrow channel across its width, magnetic flux spots nucleate at the edge and are then driven along the channel by the current. These flux "drops" are reminiscent of water drops dripping from a faucet, a model system for studying low-dimensional chaos. We use a novel high-bandwidth Hall probe to detect in real time the motion of individual flux spots moving along the channel. Analyzing the time series consisting of the intervals between successive flux drops, we find distinct regions of chaotic behavior characterized by positive Lyapunov exponents, indicating that there is a close analogy between the dynamics of the superconducting and water drop systems. 相似文献
11.
R.S. Markiewicz 《Solid State Communications》1980,33(7):701-705
The phonon wind which generates the characteristics cloud of electron-hole droplets in Ge cannot be composed solely of phonons produced via Auger recombination in drops. The nearly constant droplet density in the cloud and the rapid expansion of the cloud both point to an extra source of phonons spatially localized near the crystal surface and formed during the initial thermalization of hot carriers. Most experiments, including recent measurements of droplet velocities, are consistent with about 10–20% of the wind phonons being of thermalization origin. 相似文献
12.
S. K. Aslanov 《Technical Physics》1999,44(11):1386-1387
13.
The interaction of two light filaments propagating in air is simulated. Simulations show that the interaction of the two light filaments displays interesting features such as attraction, fusion, repulsion, and spiral propagation, depending on the relative phase shift and the crossing angle between them. A long and stable channel can be formed by fusing two in-phase light filaments. The channel becomes unstable with the increase of the crossing angle and phase shift. The interaction of two light filaments in different planes is studied and the spiral propagation is observed. 相似文献
14.
M. Vlasova P.A. Márquez Aguilar M. Kakazey V. Stetsenko A. Ragulya 《Optics & Laser Technology》2010,42(1):8-17
The laser treatment of two-layer Si-Al2O3 target at λ=1064 nm and P=170 W in a N2+O2 atmosphere by electron microscopy, atomic force microscopy, X-ray microanalysis, and IR-spectroscopy was investigated. It is established that in the stage of fracture of a silicon plate, the ablation products were silicon clusters into which, when passing over, oxygen and nitrogen diffused. On collective plate, a SiOxN composite film formed. In the stage of fracture of an alumina plate, the oxidation of silicon in the channel zone and the interaction of Al and Si oxides, accompanied by their nitration, occurred. In this stage, evolved oxide vapors and ejected mullite drops deposit on the SiOxN film. On collective plate, mullite nanowhiskers grew from mullite drops by the vapor-liquid-solid body mechanism. 相似文献
15.
A. A. Kornilova V. I. Vysotskii N. N. Sysoev N. K. Litvin V. I. Tomak A. A. Barzov 《Moscow University Physics Bulletin》2010,65(1):46-50
The process of generation of X-ray radiation formed during the free exit of a fast stream of water in a state of cavitation
from a narrow channel was investigated both experimentally and theoretically. It was observed for the first time that the
initial part of the stream and the outlet of the channel are the sources of intensive X-ray radiation (with an activity of
0.1 Cu), which is connected with the cavitation phenomena and the following excitation of shock waves. The frequency of the
X-ray radiation depends on the composition of the radiating surface (water or the surface of the channel walls) and increases
with the increase of the atomic number of the surface. The mechanism of radiation generation is connected with the influence
of cavitation shock waves formed on the nearest interface (water-air, water-metal, metal-air, air-metal, etc.). 相似文献
16.
Interaction of counterpropagating light beams in a photopolymerizable composite is studied numerically and experimentally. We propose a qualitative model which allows for finding the conditions of mutual trapping of the beams. It is shown that a single nonsplitting channel between two multimode optical fibers can be formed in an acrylic photopolymer if the angle between the beams does not exceed 4°. 相似文献
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19.
Highly efficient transmission of 1.5-microm light in a two-dimensional (2D) photonic crystal slab waveguide is experimentally demonstrated. Light waves are shown to be guided along a triple-line defect formed within a 2D crystal and vertically by a strong index-guiding mechanism. At certain wavelength ranges, complete transmission is observed, suggesting lossless guiding along this photonic one-dimensional conduction channel. 相似文献
20.
The band alignment in AlGaN/GaN HEMT devices was investigated using scanning photocurrent microscopy (SPCM) with UV and visible light sources. The polarity of the SPCM on the conduction channel exhibited a switching behavior from p-type to n-type response as the gate bias was increased. The flat-band voltage, which was higher than the DC turn-on voltage, indicates that an ohmic metallic contact was formed for electron transport. We obtained the band offset between the conduction band and the metal Fermi level, which yielded a value of 2.1 eV on average. 相似文献