Levitating states of superconducting rings in the field of a fixed ring with constant current

We consider the possibility of designing a plasma trap with a magnetic system formed by super-conducting rings and coils levitating in the field of a fixed coaxial coil carrying constant current. An analytic dependence of the potential energy of such a system with one or two levitating superconducting rings having trapped preset magnetic fluxes on their coordinates in the uniform gravitational field is obtained in the thin ring approximation. Calculations performed in the Mathcad system show that equilibrium states of such a system exist for certain values of parameters. Levitating states of a single superconducting ring and two superconducting rings in the field of the coil with constant current are observed experimentally in positions corresponding to calculated values.     

Studying the effects of temperature and radiation on the Al x O1 − x /TiNC system

The penetration of hydrogen through protective layers of aluminum oxide fixed on the surface of nanocrystalline (NC) titanium is studied. A film 400 nm thick is prepared by the magnetron sputtering. Radiation- and thermally-induced gas release are employed. It is found that the Al _x O_1?x film prevents the release of hydrogen from a sample under both radiation and thermal effects. The temperature of hydrogen extraction from metal hydride accumulators can be reduced by 200–250°C, provided that heating is performed under conditions of surface irradiation by electrons with energies of ～30 keV and current densities of 2 to 3 μA cm^?2.     

Mathematical simulation of the shock compression of porous molybdenum using a heterogeneous model

The shock compression of a heterogeneous material is numerically simulated. The physical model used for the simulation is based on a layered model of a porous material and consists of a set of thin matrix plates with a known equation of state that are separated by filler layers also with a known equation of state. The model is intended to calculate the parameters (pressure, temperature, mass velocity) of shock compression of the matrix and the filler of heterogeneous materials during their one-dimensional shock compression in terms of a developed hydrodynamic code. The adequacy of the proposed model is tested on porous molybdenum during shock-wave loading to a pressure of 15–70 GPa and a temperature of 4000 K.     

Gold nanoparticle production by laser ablation in liquid nitrogen medium followed by cryogenic medium substitution with ethanol

The use of liquid nitrogen as a medium for laser ablation made it possible to obtain Au particles shaped as cores, cores/hollow shells, and hollow shells by radiation of a picosecond Nd:YAG laser. In this case, the substitution of the cryogenic liquid medium of the colloid by evaporating on the surface of a room-temperature liquid causes the shift and broadening of the plasmon resonance peak of Au nanoparticles, which results from the formation of fractal nanoparticle aggregates.     

Nonlinear Channels of Werner States

We study the nonlinear positive map of the density matrix of two-qubit Werner states, called the nonlinear channel. The map ρ → Φ(ρ) is realized by the rational function Φ. We discuss the influence of the map on the entanglement properties of the transformed density matrix. We investigate the violation of the Bell inequality (CHSH inequality) for the two-qubit state Φ(ρ). The nonlinear channels under discussion create the entangled state from a separable Werner state. We study the quantum spin tomograms of the states.     

Polydisperse structures of composites with random elastic properties of inclusions

A generalized self-consistent method [1, 2] is developed and applied to the boundary-value problems of composites with random elastic properties of inclusions. The approach suggested makes it possible to allow for a random mutual arrangement, statistical dispersion of elastic properties and sizes of the inclusions, and their mutual correlation in terms of special homogenized indicator functions. For comparison, the analytical solutions and those obtained from a corresponding sequence of H+1 (H=0,1,…) linked homogenized problems of the self-consistent method for the strain distribution in the inclusions and for the tensor of effective elastic properties of the composite are given. A numerical calculation of the effective transversely isotropic elastic characteristics for a unidirectional polydisperse fibrous composite is also presented. Translated from Mekhanika Kompozitnykh Materialov, Vol. 36, No. 1, pp. 33–58, January–February, 2000.     

On the gyroscopic stabilization of conservative systems

We consider conservative systems with gyroscopic forces and prove theorems on stability and instability of equilibrium states for such systems. These theorems can be regarded as a generalization of the Kelvin theorem to nonlinear systems.     

Search for P-ODD asymmetry in the radiative cross-section of the interaction of neutrons with lead nuclei

The P-odd effect in the radiation cross section of capture of longitudinally polarized neutrons in a sample of natural lead is measured. The experiment was performed at PF1B facility at the Institut Max von Laue-Paul Langevin. The neutron polarization P _n was 92%, the total flux of polarized neutrons was ～3 × 10¹⁰ n/s, and the mean neutron wavelength was λ = 4.7 Å. Taking into account “0-test” we estimated the asymmetry: a _γ(^natPb) = (2.3 ± 3.5) × 10^?7, i.e., α _γ ≤ 8.1 × 10^?7 at 90% confidence level.     

一维云粒子激光探测仪研制及探测数据分析

阐述基于Mie散射理论和激光技术而研制的云粒子探测仪的相关问题。利用m量级的小孔光阑模拟感应区域的散射光,并对系统的探测敏感区域面积进行测定;通过使用不同直径的标准粒子对系统进行标定,得到可靠的响应曲线,用于定量测量云粒子尺度谱及粒子数密度。在进行了一系列实验室内的实验之后,将仪器装载在飞机上进行穿云飞行测量实验,表明了该仪器在飞行过程中工作正常、稳定,并且能够即时地显示采样区内云粒子尺度谱分布和数浓度;通过分析探测得到的数据,并与云粒子谱分布进行比较,确认了探测数据有效可靠,反映了该仪器具有良好的测云能力。