蒙特卡罗法用于机械制冷机污染传输特性的仿真计算

为了优化结构设计和建立标准的污染控制体系来提高机械制冷机的运行寿命,需要深入研究污染气体在制冷机管道内的传输机理。采用直接模拟蒙特卡罗(DSMC)方法对污染气体的传质过程进行理论仿真,设计编写软件程序,计算了分子流状态下制冷机内污染气体分子通过圆管和环形管路等微通道的传输几率。得到关键管道的传输几率小于3%,并比较了不同结构尺寸管路的传输几率。     

不可压核废料污染问题沿特征线的混合有限元方法

本文对具有分子弥散项的不可压核废料污染问题提出了沿特征方向的混合元离散格式，即对流动方程采用混合元格式，而对浓度方程和传热方程沿特征方向有限元离散。我们的论证表明：该格式具有最优收敛精度；时间步长△ｔ的前置常数仅依赖二阶方向导数；对△ｔ的限制由标准元方法中的△ｔ＝ｏ（ｈ）＾［２］减弱为△ｔ＝Ｏ（ｈ）。     

大圆片批生产中的在线检测工艺及设备

立足ＩＣ生产线管理工程的角度，系统地分析和讨论了由加工设备产生的粒子对器件成品率的影响情况及采用先进的检测手段，控制污染粒子，提高成品率的有效途径。     

双束衍射法,污斑法,污线法厚度测定比较与分析

对用电子显微镜测量薄膜厚度的三种方法：双束衍射法、污斑法、污线法进行了实验及比较分析。结果表明：污线法操作简单、使用方便、定位准确、测量误差小，是一种较为理想的测厚方法。     

Manganese silicide single crystal and films deposited on Si(1 1 1): A comparative spectroscopic study

A comparative experimental study is presented of the electronic properties of MnSi films grown on Si(1 1 1) and of MnSi single crystals, using X-ray absorption spectroscopy (XAS), and core level and valence band photoemission spectroscopy (PES). No significant differences in the electronic structure of the two systems can be found.Absorption measurements on the Mn 2p threshold show a mixed valence ground state, where the multiplet structure is washed out by the hybridisation of the Mn 3d states with the Si sp states. These results are also confirmed by photoemission (PE) spectra from the valence band and the Mn 3s, 3p and 2p core levels.Strong attention has been paid to the effect of contamination. The occurrence of multiplet effects in the absorption spectra indicates unambiguously the localisation of the Mn 3d electrons in Mn-O bonds, which strongly influences the electronic properties of these systems.     

重金属杂质对SIMOX片的沾污研究

对国内外几种SIMOX硅薄样品进行位错密度测量,再用紫外光致荧光法（UVF）对其在集成电路工艺流片前后的Fe,Cu,Ni,Mo等重离子沾污作对比测定,结合SIMOX／MOS管的漏电行性,作为简要的机理分析,结果表明,重离子沾污不但在形成SIMOX结构时产生,在集成电路工艺流片过程中也会发生,并明显影响MOSFET的性能,重金属杂质的沾污程序与SIMOX材料的位错密度密切相关,位错密度可能是沾污重金属原子的吸收中心。要降低重金属杂质的沾污首先必须降低SIMOX材料的位错密度。     

百级洁净室洁净度异常的成因分析和处理方法

探讨在百级洁净室处理洁净度异常问题的思路、方法和手段。     

流体中微粒污染物立体尺寸测量方法

利用“近景痒体摄影测量”方法,对流体中污染颗粒的立体形状及立体尺寸进行测量。通过两套摄影系统,从不同角度摄取颗粒的立体像对,并将像对转换成数字图像对,然后利用计算机软件程序对数字图像对进行处理,以获得颗粒的立体信息,证明这种方法的可行性。     

Robustness of optimal portfolios under risk and stochastic dominance constraints

Solutions of portfolio optimization problems are often influenced by a model misspecification or by errors due to approximation, estimation and incomplete information. The obtained results, recommendations for the risk and portfolio manager, should be then carefully analyzed. We shall deal with output analysis and stress testing with respect to uncertainty or perturbations of input data for static risk constrained portfolio optimization problems by means of the contamination technique. Dependence of the set of feasible solutions on the probability distribution rules out the straightforward construction of convexity-based global contamination bounds. Results obtained in our paper [Dupa?ová, J., & Kopa, M. (2012). Robustness in stochastic programs with risk constraints. Annals of Operations Research, 200, 55–74.] were derived for the risk and second order stochastic dominance constraints under suitable smoothness and/or convexity assumptions that are fulfilled, e.g. for the Markowitz mean–variance model. In this paper we relax these assumptions having in mind the first order stochastic dominance and probabilistic risk constraints. Local bounds for problems of a special structure are obtained. Under suitable conditions on the structure of the problem and for discrete distributions we shall exploit the contamination technique to derive a new robust first order stochastic dominance portfolio efficiency test.