Optimum parameters for sideband cooling of a 40Ca+ ion

Optimum conditions for sideband cooling of ⁴⁰Ca⁺ are numerically analyzed and appropriate parameters are evaluated. The dependence of optimum parameters for sideband cooling on the realistic experimental conditions, such as laser linewidth or heating rate, is investigated. For experimental verification of the analysis, a single ⁴⁰Ca⁺ is sideband-cooled using parameters based on the analysis, and the achieved average oscillation quantum numbers are evaluated. As a result, a good agreement between the experimental value and numerical analysis is obtained.     

The importance of imaging conditions in scanning tunneling microscopy for the determination of surface texture and roughness

We show that the control conditions in the feedback loop of a scanning tunneling microscope (STM) affect the values of the surface texture parameters, including fractal characterization, when they are calculated from STM images of the surface. The main surface texture parameters (such as the r.m.s. roughness, kurtosis, skewness, and average wavelength) show a strong dependence on the conditions used in the feedback loop for imaging. Fractal character changes also with feedback parameters. The quality of the STM images can be measured quantitatively by using some of the surface texture parameters.     

Transition states in the melting of germanium in dynamic and quasistatic regimes

The conditions under which transition states arise and exist during the melting of germanium are identified by digital differential-thermal analysis. The pre-and postmelting cooperative effects arising under real conditions in dynamic and quasistatic regimes are nonequilibrium phase transitions and can be characterized by a system of thermodynamic parameters. Instability of the thermodynamic parameters of the transition states is observed in quasistatic regimes as a result of dynamic instability. The system of parameters introduced characterizes the formation of a special phase state — pre-and postmelting mesophases. Zh. Tekh. Fiz. 69, 57–61 (December 1999)     

车载多传感器集成系统中线阵相机的检校方法及数据分析

传感器检校是车载多传感器集成系统中不可缺少的重要环节。介绍了一种线阵相机的数学标定方法,根据该方法设计了相关的检校设备及检校坐标系。通过对不同条件下的试验数据对比,获取最佳的实验条件和该方法所需的基本参数,并采集最佳试验条件下的试验数据,通过对数据进行处理得到投影中心坐标,对可能影响检测结果的多种实验因素进行了分析,将受这些因素影响较小的数据作为有效数据来解算最终的实验结果,可以得到较精确的结果。     

Exact solutions of non-Hermitian chains with asymmetric long-range hopping under specific boundary conditions

We study the one-dimensional general non-Hermitian models with asymmetric long-range hopping and explore how to analytically solve the systems under some specific boundary conditions.Although the introduction of long-range hopping terms prevents us from finding analytical solutions for arbitrary boundary parameters,we identify the existence of exact solutions when the boundary parameters fulfill some constraint relations,which give the specific boundary conditions.Our analytical results show that the wave functions take simple forms and are independent of hopping range,while the eigenvalue spectra display rich model-dependent structures.Particularly,we find the existence of a special point coined as pseudo-periodic boundary condition,for which the eigenvalues are the same as those of the periodical system when the hopping parameters fulfill certain conditions,whereas the eigenstates display the non-Hermitian skin effect.     

Stable Robin solid wall boundary conditions for the Navier–Stokes equations

In this paper we prove stability of Robin solid wall boundary conditions for the compressible Navier–Stokes equations. Applications include the no-slip boundary conditions with prescribed temperature or temperature gradient and the first order slip-flow boundary conditions. The formulation is uniform and the transitions between different boundary conditions are done by a change of parameters. We give different sharp energy estimates depending on the choice of parameters.     

靶上束流性能和束流传输系统参数间的关系

为了在靶上得到一定尺寸并对称分布的束流,束流传输系统应该满足一些条件.本文分析了不同初始条件下,传输系统应该满足的条件.     

New exact solutions of nonlinear Klein--Gordon equation

New exact solutions, expressed in terms of the Jacobi elliptic functions, to the nonlinear Klein--Gordon equation are obtained by using a modified mapping method. The solutions include the conditions for equation's parameters and travelling wave transformation parameters. Some figures for a specific kind of solution are also presented.     

Phase-modulated soliton of self-induced transparency

A theory of optical self-induced transparency for a two-component soliton in the presence of phase modulation is developed. It is shown that, under these conditions, it is possible to generate a vector soliton with characteristic parameters of oscillations with the sum and difference frequencies in the region of the carrier wave frequency. Explicit analytical expressions for nonlinear wave parameters under experimentally implemented conditions are given. In particular case, a well-known solution in the form of a breather is obtained.     

Stabilities of one-dimensional stationary states of Bose-Einstein condensates

We explore the dynamical stabilities of a quasi-one-dimensional (1D) Bose-Einstein condensate (BEC) consisting of fixed N atoms with time-independent external potential. For the stationary states with zero flow density the general solution of the perturbed time evolution equation is constructed, and the stability criterions concerning the initial conditions and system parameters are established. Taking the lattice potential case as an example, the stability and instability regions on the parameter space are found. The results suggest a method for selecting experimental parameters and adjusting initial conditions to suppress the instabilities.     

Numerical analysis of noise-induced regular oscillations

Constructive sufficient conditions for regular oscillations in systems with stochastic resonance are given. Using these conditions, a numerical procedure for indicating domains of parameters corresponding to the regular oscillations are proposed. The regular oscillations in systems with additive and multiplicative noise are considered. Results of numerical experiments are presented.     

Dynamics of optical pulses in periodic nonlinear fibers

Dynamics of a two-mode wave packet with strong linear and nonlinear (cross-modulation) coupling is investigated. The effect of the initial conditions of the pulse excitation on its further transformation is considered. The possibility to control the dispersion parameters of the wave packet by varying the initial conditions of its input is pointed out. The effective parameters of the dispersion and nonlinearity that govern the dynamics of an optical pulse in a periodic nonlinear fiber light guide are obtained.     

An experimental study of some parameters in lightscattering theory

Experiments have been made to determine the parameters appearing in Rozenberg's formulas for scattered radiation. It is found that the photometric parameters are related to the illumination conditions and to the parameters of small volumes. The results are compared with theoretical ones for certain particular cases.     

Analytical Solution for Peristaltic Transport of Viscous Nanofluid in an Asymmetric Channel with Full Slip and Convective Conditions

The peristaltic flow of nanofluids is a relatively new area of research. Scientists are of the opinion that the no-slip conditions at the boundaries are no longer valid and consequently, the first and the second order slip conditions should be addressed. In this paper, the effects of slip conditions and the convective boundary conditions at the boundary walls on the peristaltic flow of a viscous nanofluid are investigated for. Also, the exact analytical solutions are obtained for the model. The obtained results are presented through graphs and discussed. The results reveal that the two slip parameters have strong effects on the temperature and the nanoparticles volume fraction profiles. Moreover, it has been seen that the temperature and nanoparticles volume fraction profiles attain certain values when the first slip condition exceeds a specified value. However, no limit value for the second slip parameter has been detected. Further, the effects of the various emerging parameters on the flow and heat transfer characteristics have been presented.     

Time lag parametric identification of a hydrogen permeability model

An inverse problem with dynamic boundary conditions for determining the parameters of a hydrogen permeability nonlinear model is considered. Algorithms are proposed for estimating transport parameters of adsorption, desorption, dissolution, and diffusion depending on the body of experimental information.     

Study of the applicability conditions of the correlation function of a wideband multipath signal for estimating source coordinates

Using theoretical analysis and mathematical modeling, we study the dependence of the number of maxima in the correlation function of a wideband signal, whose parameters are related to the source coordinates, on the hydroacoustic conditions, the parameters of the receiver, and the signal/noise ratio.     

A Pair of Resonance Stripe Solitons and Lump Solutions to a Reduced(3+1)-Dimensional Nonlinear Evolution Equation

With symbolic computation, some lump solutions are presented to a(3+1)-dimensional nonlinear evolution equation by searching the positive quadratic function from the Hirota bilinear form of equation. The quadratic function contains six free parameters, four of which satisfy two determinant conditions guaranteeing analyticity and rational localization of the solutions, while the others are free. Then, by combining positive quadratic function with exponential function, the interaction solutions between lump solutions and the stripe solitons are presented on the basis of some conditions. Furthermore, we extend this method to obtain more general solutions by combining of positive quadratic function and hyperbolic cosine function. Thus the interaction solutions between lump solutions and a pair of resonance stripe solitons are derived and asymptotic property of the interaction solutions are analyzed under some specific conditions. Finally, the dynamic properties of these solutions are shown in figures by choosing the values of the parameters.     

Majorization properties of generalized thermal distributions

We examine the majorization properties of general thermal-like mixed states depending on a set of parameters. Sufficient conditions which ensure the increase in mixedness, and hence of any associated entropic form, when these parameters are varied, are identified. We then discuss those exhibiting a power law distribution, showing that they can be characterized by two distinct mixing parameters, one associated with temperature and the other with the non-extensivity index q. Illustrative numerical results are also provided.     

System of thermodynamic parameters of the transient processes under melting of crystalline substances

Thermodynamic conditions of transition states at the melting of crystalline materials have been investigated by the technique of digital differential thermal analysis. Cooperative pre-and post-melting effects are non-equilibrium phase transitions and can be characterized by a system of thermodynamical parameters J. This system of parameters characterizes the formation of specific structure states in a material as pre-and post-melting mesophases.     

Effect of slip boundary condition on flow and heat transfer of a double fractional Maxwell fluid

The purpose of the present paper is to investigate the flow and heat transfer of a double fractional Maxwell fluid with a second order slip model. The fractional governing equations are solved numerically by using the finite difference method. By comparing the analytical solutions of special boundary conditions, the validity of the present numerical method is examined. The effects of the two slip parameters and the fractional parameters on the velocity and temperature distribution are presented graphically and discussed. The results reveal that the fractional Maxwell fluid exhibits a stronger viscosity or elasticity for different fractional parameters, and the oscillation phenomenon will gradually decrease as expected with an increase in slip parameters.