Квантовые флуктуации в лазерном солитоне

In the framework of consistent quantum electrodynamics, derived is the Heisenberg-Langevin equation for spatial laser soliton. Discussed are in detail the canonical variables for the generation field and for a material two-level medium consisting of a medium that forms laser generation and saturated absorption medium. It is assumed that laser generation evolves in time much slower than the atomic medium. This makes it possible to apply adiabatic approximation and construct a closed equation for the amplitude of the laser field. When deriving the equation special attention is paid to the definition of Langevin sources that play a decisive role in the formation of quantum statistical features of solitons. In order to provide a procedure of observation of soliton quantum squeezing, synchronization of laser generation by an external weak electromagnetic beam is introduced.

Understanding Emergent Dynamics: Using a Collective Activity Coordinate of a Neural Network to Recognize Time-Varying Patterns

In higher animals, complex and robust behaviors are produced by the microscopic details of large structured ensembles of neurons. I describe how the emergent computational dynamics of a biologically based neural network generates a robust natural solution to the problem of categorizing time-varying stimulus patterns such as spoken words or animal stereotypical behaviors. The recognition of these patterns is made difficult by their substantial variation in cadence and duration. The neural circuit behaviors used are similar to those associated with brain neural integrators. In the larger context described here, this kind of circuit becomes a building block of an entirely different computational algorithm for solving complex problems. While the network behavior is simulated in detail, a collective view is essential to understanding the results. A closed equation of motion for the collective variable describes an algorithm that quantitatively accounts for many aspects of the emergent network computation. The feedback connections and ongoing activity in the network shape the collective dynamics onto a reduced dimensionality manifold of activity space, which defines the algorithm and computation actually performed. The external inputs are weak and are not the dominant drivers of network activity.

The Research of Position Inverse Solution for 6-DOF Manipulator Based on Quaternion Algorithm

For the problem of 6-DOF serial manipulator position inverse solution, the paper proposed a new method for 6-DOF serial manipulator position inverse solution by introducing the quaternion algorithm. The relative pose transformation expression in quaternion coordinate system is proposed based on the transformation relationship between dual quaternion and double quaternion, based on which the closed equation of 6-DOF serial manipulator position inverse solution times in the form of double quaternion is established. For the obtained four position constraint equations, the Dixon resultant is constructed and a equation of 16 yuan is derived which is neither with increases root nor with the leak root. And this point is proved by the Mathematica practical calculations. The process of the method is simple. And it can not only avoid extraneous roots, but also overcome some singular position caused by the correlation equation in the process of trajectory planning, and further, the real-time performance of control process is improved.

Calculation of Energies of Coherent Interfaces and Application to the Nucleation, Growth and Coarsening of Precipitates

Interfacial energies are essential in modelling nucleation, growth and coarsening processes in solid materials; especially nucleation rates respond very sensitively to small changes of this quantity. Thus, the prediction of interfacial energies has attracted the interest of many researchers since many years. In this work, a simple concept for the calculation of energies of coherent interfaces in multicomponent systems is presented. The model advances the classical nearest-neighbor-broken-bond concept for arbitrary interface orientations and interface curvature. The obtained result is simple enough to be expressed in a single, closed equation. Consequently, it can be easily implemented in the framework of classical nucleation theory, or in complex simulation tools for precipitate evolution based on Kampmann-Wagner type models. In this paper, the theoretical background of the model is discussed, and the results are compared to experimental data. Furthermore, a size correction function for small precipitates is presented and applied to the prediction of nucleation rates. Despite the simplicity of the model, the predictions of the model are found to be in satisfactory agreement with experimental evidence.

Particles and Droplets Coagulation and Clusters Formation in the Earth’s Atmosphere and in Technical Applications

On the base of modern probability approach closed equation for probability density function of coordinates and velocities of two particles in turbulent flow is obtained. The system of equations for balance of mass, averaged velocities and intensities of turbulent chaotic motion of particles with account of correlated motion of particles are deduced. The closed expressions for intensity of relative chaotic motion between particles are obtained on the base of probability density function of particles displacement with correlation effects. Spectral presentation of second velocity moments of gas phase is used for calculation of intensity of particles relative chaotic motion. Boundary condition taking into account coefficients of new particle formation and momentum restitution during two particles collision is found. Formula for calculation of turbulent coagulation kernel of particles in gravity field is gain. Influence of cloud turbulence and turbulence in a pipe flow on intensity of droplets coagulation is studied. Strong effects of relative turbulent diffusion between droplets, droplets inertia and droplets gravitational settling on intensity of coagulation are found out. Connection between internal structure of turbulence type and coagulation rate is illustrated. The calculation results are compared with data of large eddy simulations. The results of calculation intensity of droplets relative motion in atmospheric conditions are presented.