煤层底板应力分布的相似材料模拟分析

本文根据淮北芦岭煤矿的地质条件,通过相似材料模拟实验分析了工作面生产过程中煤层底板应力分布的规律,并对底板巷道布置和回采工作面设计提出了一些合理的方案。     

ON TESTS FOR LOCAL EXTREMUM POINTS IN PROJECTION PURSUIT

ＯＮＴＥＳＴＳＦＯＲＬＯＣＡＬＥＸＴＲＥＭＵＭＰＯＩＮＴＳＩＮＰＲＯＪＥＣＴＩＯＮＰＵＲＳＵＩＴＺＨＡＮＧＪｉａｎ；ＬＩＧｕｏｙｉｎｇ（ＩｎｓｔｉｔｕｔｅｏｆＳｙｓｔｅｍｓＳｃｉｅｎｃｅ，ＡｃａｄｅｍｉａＳｉｎｉｃａ，Ｂｅｉｊｉｎｇ１０００８０，Ｃｈ...     

关于次指数分布性质的一个反例

Cline于1987年发表了有关次指数分布性质的论文"Convolutions of distributions with exponential and subexpo-nential tails".然而,Shimura和Watanabe通过构造反例表明其中的推论3.2(i)的证明存在着逻辑漏洞.本文不仅构造更严格的反例以说明这个逻辑问题,而且进一步构造反例说明其推论3.2(i)的结论本身也是错误的.     

一种魏格纳-威利分布交叉项剔除新算法

为抑制魏格纳-威利分布分析多分量信号时交叉项的干扰,提出了一种交叉项剔除新算法,该方法通过分析多分量信号及跳频信号的魏格纳-威利分布交叉项特性,得出其交叉项数目和频率的一般规律,然后采用带通滤波器对时频分布结果中交叉项进行滤除。理论分析和仿真验证表明,该算法可以有效剔除多分量信号魏格纳-威利分布中的交叉项干扰,且具有优异的时频聚集性。     

论椭圆偏振光的旋转方向

从椭圆偏振光的表达式出发 ,讨论了椭圆偏振光的旋转方向与位相差的关系 ,由此提出了椭圆 (圆 )偏振光旋转方向的判定法则。并针对不同的光学教材所采用的电矢量的不同表达形式 ,分析了判断椭圆偏振光旋转方向易出错的原因 ,指出了判断椭圆偏振光旋转方向应注意的问题 ;同时介绍了按电矢量的空间分布特点判断椭圆偏振光旋转方向的新方法     

单壁碳纳米管空间电场分布的理论计算

以一端封闭的单壁碳纳米管为研究对象，把碳纳米管的结构看作是由长径比很大的导体圆筒和半球壳构成的理想模型．利用其结构的空间对称性，计算出该理想模型半球壳顶端附近的电场表达式，并对电场特性作简单分析。     

Toxic Plant Resources in Panxi Area

Panxi Area is abundant in plant resources, among which toxic plants are of great value in terms of exploitation. This paper is an initiative study （via field as well as literature investigation） of the categories, distributions, and reserves of toxic plant resources in Panxi Area. The study reveals that there are 51 families （210 species） of toxic plants evenly distributed in Panxi Area, of which more than 40 species grow in all counties in the area, and more than 14 species total a reserve more than 1.0×10^5 kg. These toxic plants are of great applications to medicine, gardening, biopesticide industry, environmental engineering, and oil manufacturing. Rhododendron molle, Anisodus acutangulus, Arisaema erubesocens, Stellera chamaejasme, Rhytolacca acinosa, Rheum officinale, and Azadiralta indica etc are the typical toxic plants with great value of exploitation in Panxi Area.     

OPTIMAL AND ROBUST DETECTION OF MULTIVARIATE OUTLIERS FOR ELLIPTICALLY CONTOURED DISTRIBUTION

The outlier problem for a multivariate elliptically contoured distribu-tion's random sample with mean slippage is defined and the likelihood ratio test ofthe null hypothesis,in which there are no outliers,versus the alternative hypothesis,in which some outliers are present,is derived.We show that the testing problemis invariant under a group of affine transformations and obtain the maximal in-variance which is equivalent to the likelihood ratio testing statistic.Furthermore,the non-null and null density distribution functions of the likelihood ratio testingstatistic are derived.We find that the null density distribution function of thetesting statistic is robust and the density distribution function is a monotonicallikelihood ratio function of the maximal invariance.Therefore,the likelihood ratiotest is a uniformly most powerful invariant test among the group of affine transfor-mations.In the last section,we give an example of detecting multivariate outliersin elliptically contoured distribution.     

固液界面高分子吸附的格点密度泛函

提出一个固液界面高分子吸附的格点密度泛函理论。该理论解释了相邻格点的相互作用以及由高分子链连接导致的长程相关性。在均相混合Helmholtz自由能和简单加权方法的基础上,构建了一个包含局域和非局域贡献的Hemholtz自由能泛函。该理论所预测的密度分布与计算机模拟结果吻合很好,与Scheutjens-Fleer理论结果相比有明显的改进。