Effects of Solid Solution Treating on the Microstructureand Damping Behaviour of MnCuNiFe Alloys

一个高抑制条件容易在 Mn-(16-24 )Cu-(4-6 ) Ni-2Fe 被获得(在。%) 合金，当冷却时，率在 1173 K 在稳固的答案处理以后被控制。在 10 h 的对数的减少的温度依赖者变化使样品凉下来，这被观察对合金作文敏感。作为与熄灭处理的水相比，控制了 10 h 冷却由在合金生产充实 Mn 的矩阵部分广泛地改进合金的 T//N 温度。计算建议在矩阵部分的 Cu 和 Ni 内容的相对减少被 Ni 内容在原来的合金统治，并且因此， Cu 的体积部分，充实 Ni 猛抛被估计分别地在 4Ni 和 6Ni 合金是大约 20% 和 10% 。作为结果，为每合金的 T//N 温度，相应于对数的减少的升起的温度，在充实 Mn 的矩阵与 Cu，和 Ni 有关。左钩住的存在 110 条正确钩住 twinning 边界在 4Ni 和 6Ni 合金的微观结构被证实。然而，相对格子紧张， twinning 边界扮演提供，在二合金被发现大部分不同。有更小的取向偏差的边界能由周期的移动容易协调外部压力，这被考虑，因此，发生在 10 h 的更宽广的抑制山峰使 6Ni 凉下来合金变得可行。电子衍射结果也在矩阵阶段显示许多亚水晶的可能的形成，它相对在一些不变的飞机上被旋转。那些亚水晶边界可能在在 T//N 和房间温度之间的温度范围起一些变细作用。(编辑作者摘要) 9 个裁判员。

Damping-like effects in Heisenberg spin chain caused by the site-dependent bilinear interaction

We investigate a continuous Heisenberg spin chain equation which models the local magnetization in ferromagnet with time-and site-dependent inhomogeneous bilinear interaction and timedependent spin-transfer torque.By establishing the gauge equivalence between the spin chain equation and an integrable generalized nonlinear Schrödinger equation,we present explicitly a novel nonautonomous magnetic soliton solution for the spin chain equation.The results display how the dynamics of the magnetic soliton can be controlled by the bilinear interaction and spin-polarized current.Especially,we find that the site-dependent bilinear interaction may break some conserved quantity,and give rise to damping-like effect in the spin evolution.

Harmonic Damping Characteristics of Single-phase Full-bridge Rectifier Based Loads

With the rapid development of power electronic technology,many linear single-phase loads in low voltage systems are replaced by those equipped with a single-phase diode rectifier.Therefore,most of single-phase loads become harmonic producers due to their nonlinear characteristics.The nonlinear loads may have different damping characteristics at harmonic frequencies,which could cause potential power quality problems.This paper studies the harmonic damping characteristics of such nonlinear loads.The harmonic damping index is defined to quantify the damping effect of nonlinear loads of harmonic frequencies by analyzing the harmonic model.Then,the harmonic damping index of different harmonic frequencies is compared through simulations and experiments.The results show that the nonlinear load has a constant damping effect for the fundamental frequency,but a stronger damping for the harmonic frequencies.The harmonic damping of such nonlinear loads varies with the harmonic phase angle of supply voltage,and becomes stronger with the increase of the harmonic order.It implies that this type of nonlinear load may be beneficial to the suppression of harmonic resonance.

A general two-phase mixture model for sediment-laden flow in open channel

This work extends the sediment-laden mixture model with consideration of the turbulence damping and particle wake effects under the framework of improved efficiency and accuracy.The mixture model consists of the continuity and momentum equations for the sediment-laden mixture,and the continuity equation for the sediment.A theoretical formula is derived for the relative velocity between the water and sediment phases,with consideration of the effects of the pressure gradient,the shear stress and the lift force.A modified expression of the particle wake effect,inducing the local turbulence enhancement around the sediment particle,is employed to improve the turbulent diffusion of the coarse sediment.The k_(m)-ε_(m) model is proposed to close the mixture turbulence,with the turbulence damping effect due to the high sediment concentration expressed by the density-stratification term without an empirical parameter.The k_(m)-ε_(m) turbulence model requires smaller computational work and offers better results than an empirical density-stratification turbulence model in high sediment concentration cases.Consequently,with the proposed mixture model,the sediment transport in the open channel under a wide range of sediment sizes and concentrations can be revealed with the results in good agreement with experimental data for the velocity,the sediment concentration and the turbulent kinetic energy.

Rotordynamic characteristics prediction for scallop damper seals using computational fluid dynamics

Enhancing damping characteristic is one of the effective methods to solve the instability problem of the rotor system.The three-dimensional numerical analysis model of scallop damper seal was established,and the effects of inlet pressures,preswirl ratios,rotational speeds,interlaced angles and seal cavity depths on the rotordynamic characteristics of scallop damper seal were studied based on dynamic mesh method and multi-frequencies elliptic whirling model.Results show that the direct stiffness of the scallop damper seal increases with decreasing inlet pressure and increasing rotational speed and cavity depth.When the seal cavity is interlaced by a certain angle,which shows positive direct stiffness.The effective damping of the scallop damper seal increases with the increasing inlet pressure,the decreasing preswirl ratio and the rotational speed and cavity depth.There exists an optimal interlaced angle to maximize the effective damping and the system stability.The leakage of the scallop damper seal is significantly reduced with decreasing inlet pressure.The preswirl will reduce the leakage flowrate,and the rotational speed has a slight effect on the leakage performance.The leakage of the scallop damper seal decreases with increasing seal cavity depth.