Mutual Trapping Research Articles

Study on Dynamic Characteristics of Magnetic Coagulation of Fe-Based Fine Particles in Iron and Steel Industry

Fine dust, represented by Fe-based fine particles and emitted from the production process of the iron and steel industry, is the primary factor causing many diseases represented by industrial pneumoconiosis, and ultra-low dust emission has always been a thorny problem to be solved urgently. To explore the magnetic coagulation effect of Fe-based fine particles in the magnetic field when removing them from industrial flue gas by the magnetic field effect in the iron and steel industry, using FLUENT software, magnetic dipole force was added between particles through user defined function (UDF) based on the computational fluid dynamics-discrete phase model (CFD-DPM) method so that the collision process of particles was then equivalent to their mutual trapping process. Next, the effects of particle size, particle volume fraction, external magnetic field strength, and particle magnetic susceptibility on the magnetic coagulation process were comprehensively studied. Meanwhile, the proton balance equation (PBE) was solved using the partition method on the basis of the computational fluid dynamics-population balance model (CFD-PBM) to compare the coagulation removal effect under random and aligned orientations of magnetic dipoles, respectively. The results showed that the magnetic coagulation strength under the random orientation of magnetic dipoles was greater than that under the aligned orientation. When the particle size of Fe-based fine particles increased from 0.5 μm to 1.5 μm, the magnetic coagulation coefficient decreased from 0.5414 to 0.2882, and the difference in the removal efficiency under the two different orientations of magnetic dipoles became smaller. When the particle volume fraction increased from 0.01 to 0.03, the magnetic coagulation coefficient increased from 0.2353 to 0.5061, and the difference in the removal efficiency under two orientations was enlarged. When the applied external magnetic field strength increased from 0.5 T to 1.0 T, the magnetic coagulation coefficient increased from 0.3940 to 0.5288, and the magnetic susceptibility increased from 0.0250 to 0.0500, the coagulation coefficient increased from 0.3940 to 0.5288, and the difference under two orientations basically stayed unchanged.

Soliton Molecules with Two Frequencies.

We demonstrate a peculiar mechanism for the formation of bound states of light pulses of substantially different optical frequencies, in which pulses are strongly bound across a vast frequency gap. This is enabled by a propagation constant with two separate regions of anomalous dispersion. The resulting soliton compound exhibits moleculelike binding energy, vibration, and radiation and can be understood as a mutual trapping providing a striking analogy to quantum mechanics. The phenomenon constitutes an intriguing case of two light waves mutually affecting and controlling each other.

Possibility of a Femtosecond Pulse Propagation in a Nonlinear Chirped Soliton Mode in a Medium with Induced Photoluminescence

The soliton mode of a femtosecond pulse propagation in a medium with induced photoluminescence is theoretically investigated. Our study is based on a pair of nonlinear Schrödinger equations, derived for the slowly varying amplitudes of the basic wave and the luminescence wave. Under assumption of the mutual trapping of the waves, we discuss a bistable mode of the waves propagation and derived two families of nonlinear chirped elliptic soliton solutions corresponding to this bistable mode. We confirmed our analytical results by numerical simulation results, obtained using conservative finite-difference scheme.

Surface vector kink solitons

We elucidate the stability properties of vector kink solitons at an interface separating a defocusing Kerr medium and an imprinted semi-infinite photonic lattice. The mutual trapping between two orthogonally polarized components results in the formation of vector states composed of well-known components in various forms, i.e., out-of-phase kinks, in-phase kinks, and surface gap solitons. Linear stability analysis reveals that a vector soliton composed of two out-of-phase kinks or an out-of-phase kink and a surface gap soliton can propagate stably in a wide parameter region. Our finding provides an example of stable vector solitons with nonvanishing amplitudes at infinity.

Propagation of coupled dipole-mode beams in nonlocal thermal media

The mutual trapping of two dipole-mode beams is investigated numerically in nonlocal thermal media. Results show that the incoherent attraction of perpendicularly aligned dipole-mode beams can enhance the stability of their composite structure. When the powers of the dipole components are identical, the larger the power, the shorter the stable distance. While when the powers are different, the closer the powers, and the longer the stable distance. Furthermore numerical results proved that the coupled solitary structures exhibit stable propagation for much larger distances than the corresponding scalar cases.

Instability suppression of clusters of vector-necklace-ring solitons in nonlocal media

We study the instability suppression of vector-necklace-ring soliton clusters carrying zero, integer, and fractional angular momentums in nonlocal nonlinear media with an arbitrary degree of nonlocality. We show that the combination of nonlocality and mutual trapping of soliton constituent components can completely stabilize the vector-necklace-ring soliton clusters which are otherwise only quasistable in local media. Our results may be useful to studies of the novel soliton states in Bose-Einstein with dipolar long-range interactions.

Stability and dynamics of small molecules trapped on graphene

Chromatic and spherical aberration-corrected atomic-resolution transmission electron microscopy combined with density-functional theory calculations is employed to elucidate the stability and dynamics of admolecules on suspended graphene. The results presented provide evidence that the interaction between the molecules and hydrogen adatoms leads to a mutual trapping. These ``symbiotic'' configurations can explain the presence of stable admolecules on graphene at ambient temperature. It is proposed to exploit these configurations to functionalize and dope graphene.

On the mechanism of anomalous slip in bcc metals

The anomalous-slip behavior of bcc metals has been studied by TEM analyses of dislocation substructures developed in a [ 2 ¯ 9 20 ] -oriented Mo single crystal uniaxially compressed at room temperature to a total-strain of 0.4%. It is found that the initial dislocation lines in association with “grown-in” super-jogs can act as effective sources for the formation of both a 0/2[1 1 1] (Schmid factor = 0.5) and a 0 / 2 [ 1 1 ¯ 1 ] (Schmid factor = 0.167) coplanar screw dislocation arrays in the ( 1 ¯ 0 1 ) primary slip plane. The interaction between the multiplied a 0/2[1 1 1] dislocations and pre-existing a 0 / 2 [ 1 1 ¯ 1 ] dislocation segments, which block the motion of the a 0/2[1 1 1] dislocations, renders the multiplication of a 0 / 2 [ 1 1 ¯ 1 ] dislocations and leads to the formation of a 0/2[1 1 1] and a 0 / 2 [ 1 1 ¯ 1 ] dislocation arrays on the ( 1 ¯ 0 1 ) primary slip plane. The occurrence of { 0 1 ¯ 1 } anomalous slip is accordingly proposed to be resulting from the mutual trapping of a 0/2[1 1 1] and a 0 / 2 [ 1 1 ¯ 1 ] coplanar dislocation arrays on the ( 1 ¯ 0 1 ) primary slip plane, which renders a cross-slip propagation of both a 0/2[1 1 1] and a 0 / 2 [ 1 1 ¯ 1 ] screw dislocations from the ( 1 ¯ 0 1 ) plane onto the { 0 1 ¯ 1 } planes and thus activates the { 0 1 ¯ 1 } 〈1 1 1〉 slip systems.

Dynamics of coupled ultraslow optical solitons in a coherent four-state double- ${\sf \Lambda}$ system

We present a systematical investigation, both analytical and numerical, on the dynamics of two nearly lossless and distortion-free weak nonlinear optical pulses in a cold, lifetime-broadened four-state double-Λ system via electromagnetically induced transparency. Starting from the equations of motion of atomic response and probe fields, we give a detail derivation of two coupled nonlinear Schrodinger equations that control the nonlinear evolution of two probe field envelopes by means of a standard method of multiple-scales. We show that stable optical solitons with very slow propagating velocity can be generated under very low input light intensity when working in the transparency window of probe absorption spectrum induced by two continuous-wave control fields. We demonstrate that coupled optical soliton pairs are possible in the system through cross-phase modulational instability and mutual trapping effect of solitons. We provide various coupled optical soliton pair solutions explicitly and analyze their stability numerically.

Evolution and stability of holographic soliton pairs

The dynamical evolution and the stability property of both bright and dark holographic soliton pairs have been investigated numerically. Results show that mutual trapping between two beams in a pair is balanceable and both beams can survive as spatial solitons, and these solitons are stable against small perturbations.

Vector mixed-gap surface solitons

We elucidate the properties of mixed-gap vector surface solitons supported by the interface between a uniform medium and an optical lattice imprinted in a Kerr-type nonlinear medium. The components of such mixed-gap solitons emerge from different gaps of lattice spectrum and their mutual trapping results in the formation of stable vector states. The unstable soliton component is stabilized by the cross-coupling with the stable component. We show that vector mixed-gap surface solitons exhibit a new combination of properties of vectorial surface waves and gap solitons.

Observation of two-dimensional lattice vector solitons

We demonstrate the formation of fundamental and dipolelike vector solitons in an optically induced two-dimensional photonic lattice. Such vector solitons are realized by mutual trapping of two beams in the lattice. Our theoretical results are in good agreement with experimental observations.

Bi-colour spatial solitons in linearly uncoupled planar waveguides

We report on the observation of spatial optical simultons in a novel geometry consisting of two partially overlapped, linearly uncoupled planar waveguides in lithium niobate obtained by reverse proton exchange. Two orthogonally polarized modes are coupled through an off-diagonal tensor element of the quadratic nonlinearity, giving rise to second harmonic generation and mutual trapping via cascading. This phenomenon demonstrates a balance between diffraction and self-focusing for two orthogonal modes of different waveguides, and occurs at room temperature in longitudinally uniform waveguides.

Nonlinear optical beams carrying phase dislocations

We describe different types of self-trapped optical beams carrying phase dislocations, including vortex solitons and ring-like soliton clusters. We demonstrate numerically how to create such nonlinear singular beams by the interaction of several fundamental optical solitons. Mutual trapping of several solitons can be regarded as a synthesis of `soliton molecules', and it corresponds to a transfer of an initial orbital angular momentum of a system of solitons to a spin momentum of an optical vortex.

Bi-colour spatial solitons in linearly uncoupled planar waveguides

We report on the observation of spatial optical simultons in a novel geometry consisting of two partially overlapped, linearly uncoupled planar waveguides in lithium niobate obtained by reverse proton exchange. Two orthogonally polarized modes are coupled through an off-diagonal tensor element of the quadratic nonlinearity, giving rise to second harmonic generation and mutual trapping via cascading. This phenomenon demonstrates a balance between diffraction and self-focusing for two orthogonal modes of different waveguides, and occurs at room temperature in longitudinally uniform waveguides.

Mutual spatial-soliton trapping in photorefractive media: experiment versus theory

We investigate the interaction of two-dimensional solitons propagating at small angles in a photorefractive crystal. We observe fusion of the beams when the intersecting angle is lower than some critical value. We measure the critical angle for fusion for different relative phase relations of the beams and demonstrate how this effect can be used to steer and switch the propagation of an additional optical beam.

The possibility of mutual trapping of counterpropagating light beams in photopolymerizable composites

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°.

Stabilization and breakup of coupled dipole-mode beams in an anisotropic nonlinear medium

We study the mutual trapping of two dipole-mode light beams in a medium with a nonlocal anisotropic saturable nonlinearity. It is shown that the incoherent attraction of perpendicularly aligned dipole-mode beams leads to the stabilization of their composite structure. Our numerical analysis gives a stationary solution that is stable only with respect to small amplitude modulations. The coupled solitary structure disintegrates in a well-defined way when the numerical perturbations or the experimental propagation length exceeds a certain limit. In this case a new and more robust, multicomponent solitary transverse light structure consisting of two dipole-mode vector solitons will be generated.

Effect of weak discreteness on two-soliton collisions in nonlinear Schrödinger equation

We predict the possibility of strongly inelastic soliton collisions in a weakly discrete medium from the analysis of two-soliton solution to the nonlinear Schrödinger equation and confirm the prediction numerically. The effect turns out to be qualitatively independent on the particular type of perturbation. The conditions of mutual trapping of the colliding solitons are discussed as well.

Universal Mechanism for Gas Adsorption and Electron Trapping on Oxidized Silicon

We report that common gases (such as He, Ar, ${\mathrm{H}}_{2}$, ${\mathrm{O}}_{2}$, ${\mathrm{N}}_{2}$, CO) experience adsorption at oxidized silicon surfaces at 300 K via electrostatic coupling. This is deduced using contact potential measurements of the work function for gas pressure in the range ${10}^{\ensuremath{-}3}<P<{10}^{2}\mathrm{Torr}$. The adsorption can be enhanced through surface charging via internal photoemission of electrons leading to mutual electron-gas transient trapping. A simple electrostatic model based on monopole-dipole coupling results in an isotherm in agreement with the data.