铝膜厚度对铝诱导非晶硅薄膜晶化的影响

实验采用glass/a-Si:H/Al结构,在厚100 nm非晶硅膜上蒸镀了不同厚度的铝膜,利用铝诱导晶化法晶化非晶硅薄膜,结果发现经380℃退火后非晶硅薄膜晶化率在铝膜厚度与非晶硅膜相等时有最大值,且其晶化率随晶粒尺寸的增大而增大,而其表面粗糙度随铝厚度的增加而增大。     

Econometric analysis of microscopic simulation models

Microscopic simulation models are often evaluated based on visual inspection of the results. This paper presents formal econometric techniques to compare microscopic simulation (MS) models with real-life data. A related result is a methodology to compare different MS models with each other. For this purpose, possible parameters of interest, such as mean returns, or autocorrelation patterns, are classified and characterized. For each class of characteristics, the appropriate techniques are presented. We illustrate the methodology by comparing the MS model developed by He and Li [J. Econ. Dynam. Control, 2007, 31, 3396–3426, Quant. Finance, 2008, 8, 59–79] with actual data.     

Market Potential of a Fast-Food Outlet Against Location Based on Customer Traveling Distance Profiles

Abstract

This paper studies how best to estimate the market potential of a fast-food outlet based on customer traveling distance profiles. We selected two outlets from a fast-food chain in Hong Kong, one located in a business district, the other in an urban area, as typical demonstrations. According to the hourly sales indices of either outlet, sales can be categorized into four time segments. The potential market population of each time segment for each outlet is first determined from customer traveling distance profiles. The overall potential market population for each outlet is then determined. To determine the market potential of an outlet, we need to include two factors: the fraction of this population having fast food and the associated frequency of having fast food, in addition to the overall potential market population. Aspects determining these three factors are also examined.     

SOME SMALL–SAMPLE NON–PROPORTIONAL HAZARDS RESULIS FOR THE KAPLAN–MEIER ESTIMATOR

CHEN, HOLLANDER and LANGBERG (1982) presented exact small–sample results for the KAPLAN–MEIER (1958) estimator under the proportional hazards model. We present simulation results for the same estimator for small samples in a number of cases where the hazard rates are not proportional. These suggest that the proportional hazards results, especially with regard to the Mean Square Error, are typical for a fairly large variety of "non–proportionalities" that may be encountered in practice. Thus the MSE of the KAPLAN–MEIER estimator appears to be rather robust against deviations from proportionality of the survival and censoring hazard rates. We illustrate the practical importance of this property by two examples.     

基于SKA1-low的数字波束形成技术

为配合我国参与平方公里射电阵（SKA）项目,深入理解数字波束形成条件下的射电干涉观测和相应数据处理算法,提出了基于多相滤波器组信道化数字移相波束形成和基于分数阶时延滤波器数字波束形成两个技术算法,前者使用互相关法求解相移量来提高波束指向精度,后者是传统算法与射电观测理论的有效结合。首先,详细介绍了算法的理论推导并分析了它们的优缺点;然后,通过仿真实验验证了这两个算法的正确性,仿真结果表明基于多相滤波器组信道化数字移相波束形成算法相比传统算法具有一定的优越性;最后,分析了不同阶数时延滤波器对波束形成的影响并得出了相应结论。这些仿真结果及结论可为从事SKA项目的科研人员提供参考。