强聚焦混合偏振矢量光束在瑞利粒子上产生的辐射力

理论研究了强聚焦混合偏振矢量光束作用在瑞利粒子的辐射力,推导出混合偏振矢量光束深聚焦在焦平面处产生辐射力的计算表达式,数值模拟了焦平面附近轴向光束强度分布及数值孔径与径向系数对辐射力分布的影响.结果表明,强聚焦混合偏振矢量光束深聚焦后在焦平面附近产生的辐射力在一定情况下能够实现对瑞利粒子的三维捕获,并且受数值孔径和径向系数的影响,其中径向系数影响较为明显.大量数据整合结果表明当径向系数大于3时,才能实现与光阑数值孔径相匹配,完成对焦平面附近瑞利粒子的三维捕获.     

Superthermostability of nanoscale TIC-reinforced copper alloys manufactured by a two-step ball-milling process

A Cu-TiC alloy, with nanoscale TiC particles highly dispersed in the submicron-grained Cu matrix, was manufactured by a self-developed two-step ball-milling process on Cu, Ti and C powders. The thermostability of the composite was evaluated by high-temperature isothermal annealing treatments, with temperatures ranging from 727 to 1273 K. The semicoherent nanoscale TiC particles with Cu matrix, mainly located along the grain boundaries, were found to exhibit the promising trait of blocking grain boundary migrations, which leads to a super-stabilized microstructures up to approximately the melting point of copper (1223 K). Furthermore, the Cu-TiC alloys after annealing at 1323 K showed a slight decrease in Vickers hardness as well as the duplex microstructure due to selective grain growth, which were discussed in terms of hardness contributions from various mechanisms.     

微粗糙结构表面液滴浸润特性的多体耗散粒子动力学研究

超疏水表面因其优异的自洁作用一直是表面科学领域关注的重点.本文使用多体耗散粒子动力学(many-body dissipative particle dynamics, MDPD)方法模拟研究了不同粗糙结构下液滴的浸润特性, 并与Cassie-Baxter理论进行了对比. 研究使用了一种具有长吸短斥作用的流固作用函数来获得不同的液滴浸润性, 并利用一种简洁的数值方法来测量接触角. 模拟结果表明本研究方法能够稳定地捕捉到液滴在粗糙表面的静态和动态特性. 模拟了粗糙结构对三相接触线运动的黏滞作用, 与物理实验结果相符合, 表明Cassie-Baxter理论在实际应用中尚存在一定局限性. 研究分析了在动态铺展过程中的能量转化关系, 并指出在低值表面容易引起液滴反弹.     

基于单粒子模型与偏微分方程的锂离子电池建模与故障监测

锂离子电池内部结构是一种复杂的分布参数系统, 如果为了降低计算难度而使用常微分方程描述锂离子电池, 可能会引入系统误差, 降低系统模型的可信度, 需要使用偏微分方程建立分布参数系统的精确模型. 本文提出了一种基于单粒子模型和抛物型偏微分方程的锂离子电池系统建模与故障监测系统设计方法, 当锂离子浓度实测值与理想值的残差大于预设门槛时判定分布参数系统处于故障状态. 通过一个仿真实例进行了锂离子电池系统建模和故障诊断实验, 实验证明基于单粒子模型和偏微分方程的锂离子电池故障监测系统具有更高的精确度和可信度.     

绿色ACEL粉末材料的晶体粒度对发光性能的影响

目前粉末ＡＣＥＬ器件有三类：玻璃屏、塑料软屏和搪瓷屏．目前商品化的电致发光材料，每炉料大约在１００～２００克之间，粒度在１０μｍ左右，不能满足产业化的需求．影响发光材料亮度、寿命、粒度的主要因素有Ｃｕ的浓度、灼烧时间、退火方式和灼烧气氛［１，２，３］...     

超强激光等离子体中钻孔效应的二维粒子模拟

 当非均匀超短脉冲强激光照射均匀分布的过稠密等离子体时, 相对论效应导致电子质量增大,相对论电子等离子体频率减小,激光能更深地进入等离子体产生强烈吸收。由于入射激光的径向不均匀性,钻孔效应显著。通过二维粒子模拟结果清晰地观察到了等离子体通道的产生。     

A Remark on the Use of Differential Forms for the Skyrme Problem

We introduce a formulation of the Skyrme problem using differential forms. By means of this formulation, we prove first that the homothetic map between the standard three-sphere of radius R, S³ _r R⁴, and S³ ₁ is the unique minimizer, modulo isometries, of the Skyrme energy in its homotopy class, for any R less than some critical value R₀ (3/2, 2]. We then establish a stability result for this Skyrme-form problem from which we can recover the result of M. Loss and N. S. Manton which states that this homothetic map is stable only up to R = 2.     

Some Infinite-Dimensional Algebras Arising in Spin Systems and in Particle Physics and their Grand Algebra

We indicate similarities in the structure of two types of infinite-dimensional algebras, one introduced 28 years ago in connection with the mass problem of elementary particles and the other seven years ago in connection with spin systems (XY models). We show that these algebras can be considered as representations of a single Grand Algebra, the enveloping algebra of an affine Kac–Moody algebra built on the Poincaré Lie algebra. As an associative and coassociative bialgebra of operators, the latter representation of the grand algebra is a preferred nontrivial deformation of the Ising case bialgebra.     

Finite Range of Large Perturbations in Hamiltonian Dynamics

The dynamics defined by the Hamiltonian , where the _m are fixed random phases, is investigated for large values of A, and for . For a given P ^* and for , this Hamiltonian is transformed through a rigorous perturbative treatment into a Hamiltonian where the sum of all the nonresonant terms, having a Q dependence of the kind cos(kQ – nt + _m) with \Delta \upsilon$$ " align="middle" border="0"> , is a random variable whose r.m.s. with respect to the _m is exponentially small in the parameter . Using this result, a rationale is provided showing that the statistical properties of the dynamics defined by H, and of the reduced dynamics including at each time t only the terms in H such that , can be made arbitrarily close by increasing . For practical purposes close to 5 is enough, as confirmed numerically. The reduced dynamics being nondeterministic, it is thus analytically shown, without using the random-phase approximation, that the statistical properties of a chaotic Hamiltonian dynamics can be made arbitrarily close to that of a stochastic dynamics. An appropriate rescaling of momentum and time shows that the statistical properties of the dynamics defined by H can be considered as independent of A, on a finite time interval, for A large. The way these results could generalize to a wider class of Hamiltonians is indicated.     

(p,n)和(p,2n)反应激发函数的系统学研究

从普朗克(Planck)黑体辐射公式和实验测量数据出发,采用唯象的方法提出了包含两个可调参量,入射质子能量从阈能到150MeV,靶核质量数在44相似文献