Two-component solitons in a chain of dimers with Parity-Time symmetric nonlinearity

2015 ◽  
Vol 24 (03) ◽  
pp. 1550029 ◽  
Author(s):  
Wei Pang ◽  
Jun Chen ◽  
Hua Lv
Keyword(s):  
Propagation Constant ◽  
Effective Area ◽  
Parameter Plane ◽  
Linear Coupling ◽  
Waveguide Arrays ◽  
Two Component ◽  
Stable Map ◽  
Intrinsic Parity ◽  
A Chain ◽  
The Stability

We introduced a coupled waveguide arrays with intrinsic Parity-Time (PT)-symmetric nonlinearity. The system is described by a set of coupled Schrödinger equations with linear couplings and a complex nonlinearity. Two-component soliton modes are found to exist in this system. The stability of the solitons are investigated and the stable map is plotted numerically in the parameter plane of linear coupling and the strength of PT nonlinearity. The effects of the PT nonlinearity on the amplitude and the effective area of the soliton modes are studied. It is found that the PT nonlinearity can manipulate the amplitude and the propagation constant of the soliton modes. The mobility of these soliton modes are studied numerically. The soliton modes can be kicked to move and increase the PT nonlinearity will enhance the mobility. Collision of two soliton modes are investigated and the results indicates that we can control the types and properties of the collision by adjusting the linear coupling and the PT nonlinearity.

scholarly journals Study of Mechanical Behavior and Microstructure for Low-Hardness P92 Steel

2021 ◽  
Vol 2101 (1) ◽  
pp. 012074
Author(s):  
Weixin Yu ◽  
Zhen Dai ◽  
Jifeng Zhao ◽  
Lulu Fang ◽  
Yiwen Zhang
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Strength ◽  
Maximum Size ◽  
Rapid Decrease ◽  
Laves Phases ◽  
P92 Steel ◽  
A Chain ◽  
The Stability ◽  
Evolution Of Microstructure

Abstract The strength of P92 steel (tensile strength, specified plastic elongation strength) will decrease after its hardness is reduced, ferrite and carbides forming the structure. Carbides of grain size 5-6 are precipitated in the grains and grain boundaries. The martensite lath shape has completely disappeared. M23C6 carbide coarsened obviously, with a maximum size of about 500nm; The Laves phase is also aggregated and coarsened, connecting in a chain shape with a maximum size of more than 500nm. Evolution of microstructure, namely the obvious coarsening of M23C6 carbides and the aggregation and connection of Laves phases in a chain shape, are the main causes for rapid decrease in the stability of the material substructure and evident decline in mechanical properties and hardness. In addition, the MX phase did not change significantly, hardly affecting the hardness reduction of P92 steel.

Stable high dimensional solitons in nonlocal competing cubic-quintic nonlinear media

2021 ◽  
Author(s):  
Qiying Zhou ◽  
Hui-jun Li
Keyword(s):  
Propagation Constant ◽  
Nonlinear Coefficient ◽  
High Dimensional ◽  
Cubic Nonlinearity ◽  
Nonlinear Media ◽  
Nonlinear Modes ◽  
Quintic Nonlinearity ◽  
The Stability

Abstract We find and stabilize high dimensional dipole and quadrupole solitons in nonlocal competing cubic-quintic nonlinear media. By adjusting the propagation constant, cubic and quintic nonlinear coefficients, the stable intervals for dipole and quadrupole solitons which are parallel to $x$ axis and ones after rotating 45 degrees counterclockwise around the origin of coordinate are found. For the dipole solitons and ones after rotating, their stability is controlled by the propagation constant, the coefficients of cubic and quintic nonlinearity. For the quadrupole solitons, their stability is controlled by the propagation constant and the coefficient of cubic nonlinearity, rather than the coefficient of quintic nonlinearity, though there is a small effect of the quintic nonlinear coefficient on the stability. Our proposal may provide a way to generate and stabilize some novel high dimensional nonlinear modes in nonlocal system.

scholarly journals Probing the stability and magnetic properties of magnetosome chains in freeze-dried magnetotactic bacteria

2020 ◽  
Vol 2 (3) ◽  
pp. 1115-1121
Author(s):  
Philipp Bender ◽  
Lourdes Marcano ◽  
Iñaki Orue ◽  
Diego Alba Venero ◽  
Dirk Honecker ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetite Nanoparticles ◽  
Magnetotactic Bacteria ◽  
Magnetic Compass ◽  
High Quality ◽  
Magnetospirillum Gryphiswaldense ◽  
Freeze Dried ◽  
A Chain ◽  
The Stability

Magnetospirillum gryphiswaldense biosynthesize high quality magnetite nanoparticles, called magnetosomes, and arrange them into a chain that behaves like a magnetic compass.

scholarly journals Analysis of stability problems via matrix Lyapunov functions

1990 ◽  
Vol 3 (4) ◽  
pp. 209-226 ◽  
Author(s):  
Anatoly A. Martynyuk
Keyword(s):  
Lyapunov Functions ◽  
Systems Of Nonlinear Equations ◽  
Matrix Functions ◽  
Singularly Perturbed Systems ◽  
Two Component System ◽  
Two Component ◽  
Lyapunov Matrix ◽  
Analysis Of Stability ◽  
The Stability ◽  
The Given

The stability of nonlinear systems is analyzed by the direct Lyapunov's method in terms of Lyapunov matrix functions. The given paper surveys the main theorems on stability, asymptotic stability and nonstability. They are applied to systems of nonlinear equations, singularly-perturbed systems and hybrid systems. The results are demonstrated by an example of a two-component system.

scholarly journals Numerical Simulation of Mutual Influence in 470 Sailing Hull and Rudder at Different Hull Speeds

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 134
Author(s):  
Shijie Lin ◽  
Yong Ma ◽  
Weitao Zheng ◽  
Zhengye Pan
Keyword(s):  
Numerical Simulation ◽  
Stokes Equations ◽  
Mutual Influence ◽  
Effective Area ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Stall Angle ◽  
The Stability ◽  
Viscous Flow Field ◽  
Reducing Energy

A 470 sailing race requires effective cooperation between athletes to optimize the hull position and the correct heading. To understand the effect of the hull on the maneuverability of the rudder and the influence of the rudder on the stability and rapidity of the hull at different ship speeds, requires numerical 3D simulation and research on the viscous flow field of 470 sailing based on Reynolds-averaged Navier-Stokes equations. The results show that the rudder can reduce the wave making characteristics of the hull, reducing energy loss and thus improving the hull’s rapidity when the speed is greater than 6 m/s, as the effective area of rudder decrease and increases the stall angle, which reduces the manipulatable performance of the rudder to some extent. This study could quantify the performance of the hull and rudder at different speeds. Moreover, this study might provide strategies for the athletes to effectively control the rudder and hull at different speeds.

scholarly journals Are Pressure-Confined Clouds in Galactic Halos Possible Models of Lyman Alpha Clouds?

1999 ◽  
Vol 186 ◽  
pp. 481-481
Author(s):  
Keiko Miyahata ◽  
Satoru Ikeuchi
Keyword(s):  
Galactic Halo ◽  
Observational Constraints ◽  
Galactic Halos ◽  
Tidal Disruption ◽  
Lyman Alpha ◽  
Hot Gas ◽  
General Stability ◽  
Luminous Galaxies ◽  
Two Component ◽  
The Stability

Our understanding of the Lyα forest has changed considerably following observations by HST and Keck. Lyα clouds at low redshifts (z < 1.7) observed by HST showed two unexpected features: Lanzetta et al. (1995) found that most luminous galaxies at such redshifts produce Lyα absorptions at mean impact parameter ~160h−1kpc, and established the association between Lyα clouds and galaxies. Ulmer (1996) pointed out the strong clustering of Lyα clouds in this redshift range. Motivated by the above, we propose a two-component protogalaxy model for the Lyα clouds based upon our previous work (Miyahata & Ikeuchi 1995). In our model, the Lyα clouds are stable cold clouds confined by the pressure of ambient hot gas in a galactic halo. We determine the properties of these cold clouds and hot gas on the basis of theoretical and observational constraints. We take into account the stability of a cold cloud in the galactic halo in addition to the general stability conditions in a two-component medium (e.g. Ikeuchi & Ostriker 1986), and compare the derived quantities of Lyα clouds in the galactic halo and in the intergalactic medium at both high and low redshifts. We conclude that the ciondition that a cloud is stable against both evaporation and tidal disruption by a hot galactic halo is very restrictive. In the most noteworthy example at z ~ 0.5, a pressure-confined, stable spherical Lyα cloud with NHI = 1014cm−2 cannot survive in the galactic halo, although much higher column density clouds of NHI = 1017cm−2 can. Miyahata & Ikeuchi (1997) discuss how these results constrain an alternative model for Lyα clouds associated with the galaxies observed by Lanzetta et al. (1995).

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