ANALYSIS OF SHIP MANEUVERING PERFORMANCES AND ICE LOADS ON SHIP HULL WITH DISCRETE ELEMENT MODEL IN BROKEN-ICE FIELDS

采用离散元模型对碎冰区浮冰与船舶结构的相互作用进行了数值研究。碎冰由三维圆盘单元构成,并考虑其在海流作用下的浮力、拖曳力和附加质量。船体结构由一系列三角形单元组合构造。通过海冰与船体单元间的接触判断和接触力计算,确定海冰与船体结构之间的相互作用。采用以上离散单元模型对不同冰况（冰速、冰厚、冰块尺寸和密集度）以及航速条件下,海冰对船体的动力作用过程进行了数值分析,对比分析了以上因素对船体冰载荷的影响,可为冰区船舶的安全运行和结构设计提供一定的借鉴作用。     

Mode decomposition of nonlinear eigenvalue problems and application in flow stability

Direct numerical simulations are carried out with different disturbance forms introduced into the inlet of a flat plate boundary layer with the Mach number 4.5. According to the biorthogonal eigenfunction system of the linearized Navier-Stokes equations and the adjoint equations, the decomposition of the direct numerical simulation results into the discrete normal mode is easily realized. The decomposition coefficients can be solved by doing the inner product between the numerical results and the eigenfunctions of the adjoint equations. For the quadratic polynomial eigenvalue problem, the inner product operator is given in a simple form, and it is extended to an Nth-degree polynomial eigenvalue problem. The examples illustrate that the simplified mode decomposition is available to analyze direct numerical simulation results.     

一种快速计算分层媒质中三维目标电磁散射的方法

基于稳定双共轭梯度-快速傅立叶变换（BCGS-FFT）和离散复镜像方法（DCIM），快速求解了平面分层媒质中三维目标电磁散射．首先引入离散复镜像方法用以加速并矢格林函数的计算，并针对三维问题，采用了裂项计算并矢格林函数，进一步减少了时间需求．然后在离散积分方程中采用弱模式并矢格林函数，降低了积分方程的奇异性，加快了迭代算法的收敛．数值结果表明，本文方法计算耗时较改进前减少90％，适于电大尺寸问题的求解．     

Adjoint classes of functions in the H<Subscript>1</Subscript> sense

Using the concept of the H₁-integral, we consider a similarly defined Stieltjes integral. We prove a Riemann-Lebesgue type theorem for this integral and give examples of adjoint classes of functions.     

煤烟聚集粒子的光散射特性研究(英文)

基于分形理论,用计算机模拟了由球形基本粒子构成的煤烟聚集粒子。利用离散偶极子近似方法(Discrete Dipole Approximation)研究了煤烟聚集粒子的散射特性,讨论了分形煤烟聚集粒子的散射强度随煤烟聚集粒子的分形结构、大小、相对折射率及入射波波长变化情况。     

A trace formula of a boundary value problem for the operator Sturm-Liouville equation

We obtain a regularized trace formula for the operator Sturm-Liouville equation with a boundary condition depending on a spectral parameter.     

Approximation of quantum Lévy processes by quantum random walks

Every quantum Lévy process with a bounded stochastic generator is shown to arise as a strong limit of a family of suitably scaled quantum random walks.     

Convergence of Solutions of Discrete Reflected Backward SDE＇s and Simulations

The objective of this paper is to introduce elementary discrete reflected backward equations and to give a simple method to discretize in time a （continuous） reflected backward equation. A presentation of numerical simulations is also described.     

Finiteness of the discrete spectrum of the Schrödinger operator of three particles on a lattice

We consider a system of three quantum particles interacting by pairwise short-range attraction potentials on a three-dimensional lattice (one of the particles has an infinite mass). We prove that the number of bound states of the corresponding Schrödinger operator is finite in the case where the potentials satisfy certain conditions, the two two-particle sub-Hamiltonians with infinite mass have a resonance at zero, and zero is a regular point for the two-particle sub-Hamiltonian with finite mass.