A NEW NUMERICAL METHOD FOR TWO-PHASE IMMISCIBLE INCOMPRESSIBLE PROBLEM

Two-phase, immiscible, incompressible flow in porous media is governed by a system of nonlinear partial differential equations. In most practical applications convection physically dominates diffusion, and the object of this paper is to develop a finite difference method combined with the method of characteristics and the lumped mass method to treat the parabolic equation of the differential system. This method is shown satisfy the maximum principle and its error analysis is presented.     

一类带等式约束非光滑最优化问题的逐次二次规划方法

本文对一类带等式的非光滑最优化问题给出了一种逐次二次规划方法。这类问题的目标函数是非光滑合成函数，约束函数是非线性光滑函数。该方法通过逐次解二阶规划寻找搜索方向，使用ｌ１－罚函数的非精确线搜索得到新的迭代点。我们证明了算法的全局收敛性并给出了数值试验结果。     

多个尺度函数产生的多分辨率分析

本文考虑一般细分方程ψｉ（ｘ）＝Σ１≤ｊ≤ＮΣｋ∈Ｚｃｉｊ（ｋ）ψｊ（２ｘ－ｋ），解的存在性，正则性和稳定性，及｛ψｉ｝１≤ｉ≤Ｎ产生Ｌ＾ｐ多分辨率分析的条件。     

ASYMMETRY PARAMETERS AND DIFFERENTIAL CROSS SECTIONS FOR PHOTOIONIZATION-EXCITATION OF HELIUM

Asymmetry parameter β₂ for photoionization of helium leaving the He⁺ ion in the n=2 level and differential cross sections(DCSs) in the n=2,3,4 levels with photon emission angle θ=90⁰ are provided at photon energies 69-76.8 eV employing the R-matrix method with a 20-term target representation, in which five polarization orbitals \bar{6}l are included. The asymmetry parameter β₂ and the DCS, in the n=2 level in the region of 69-73 eV, are in good agreement with available experimental and theoretical results. Above the n=3 threshold, we present new theoretical results along with measurements. No theoretical and experimental results can be used to compare with the present calculations of the DCSs for photoionization into the He⁺ ion in the n=3,4 levels.     

Aufeinanderfolgende Elemente in multiplikativen Zahlenmengen

LetM be a multiplicative set with 1M andmnM if and only ifmM,nM for (m,n)=1. It is shown by elementary means that there exists the asymptotic density of the setM(M–1) for every multiplicative setM. The density is positive if and only ifM possesses a positive density and 2M for some . This result is slightly generalized to sums over multiplicative functionsf with |f|1.     

Scattering of gaussian beam by a ferrite cylinder

The scattering of a Gaussian beam by a ferrite cylinder is analyzed using two methods. The spatial pictures in the amplitude of the total Gaussian beam near the cylinder resulting from the two methods are both clarified and compared. The scattering by a ferrite cylinder coating a dielectric sleeve is also presented.     

Freeman离子源的特性与改进研究

此文简要叙述用于离子束材料改性装置的Ｆｒｅｅｍａｎ离子源的特性，其主要参数：灯丝电流、孤压、磁场、气流量和吸极电压与引出离子束流强的关系。对源体内部因微漏冷却水（真空度由３．９×１０－４降至４．２×１０－４Ｐａ）致使气体分子电离、起弧困难和等离子体不稳作了实验研究；对灯丝与弧室间的氮化硼绝绝物上沉积被溅射出的Ｗ、Ｍｏ原子导致绝缘下降、灯丝寿命缩短进行了部份结构改进。结果表明，提高加工工艺，确保真空系统密封性能和输入气体纯度对弧室内气体分子碰撞电离和等离子体的稳定至关重要；在ＢＮ绝缘物上放置钼制屏蔽罩有效地屏蔽掉Ｗ、ＭＯ原子沉积使灯丝寿命延长一倍，达到了４０小时。     

表面效应对γ-Fe2O3微粉饱和磁化强度的影响

我们制备了直径为80—700A的γ-Fe₂O₃微粉,测量了它的比饱和磁化强度σ_s和比表面积S_a,得出经验公式:σ_s(s=σ_s(∞)(1—aS_a)。假定微粉由两部分组成:第一部分是表面层,在磁场的作用下,它的磁矩只能转到与磁场成某个角度;第二部分是内部,它的磁矩可以转到磁场的方向。从这个简单的模型出发,上述的经验公式可以得到较好的解释。 关键词：