统计学在证券期货市场中的应用(Ⅲ) 二.股票价格指数(下)新华财经股指的编制

本文通过非参数检验、相关分析等数理统计方法 ,讨论了三种不同权数下 ,采样股股票价格指数之间的差异 ,以及同现有综合股票价格指数的相关性 ,并从我国实际出发 ,分析了政策、消息、扩容对采样股股票价格指数影响力的大小     

谈谈研究式的学习

一位学生,应当学习课本上的知识,这一过程主要在课堂进行.但对一位优秀的学生,仅仅依靠课本来学习是远远不够的.即使就知识方面来说,中学阶段所能学的内容是很多的,而课本上的充其量仅占十分之一,更何况要培养各种能力.要取得长足的进步,最好是进行研究式的学习.     

第33届国际数学奥林匹克

第33届IMO于1992年7月在俄罗斯首都莫斯科举行。我国代表队在苏淳、严镇军两位领队的率领下,取得6枚金牌,总分第一。中华台北队首次参赛,也取得3银2铜,总分124,在60多个国家、地区中居17位。前6名成绩如下:     

Hydrothermal Synthesis and Crystal Structure of a Manganese(II) Coordination Polymer with 1,1′-Biphenyl-2,2′,6,6′-tetracarboxyl Acid and 2,2′:6,2′′-Terpyridine Ligands

The title compound {[Mn(H2BPTC)(tpy)(H2O)]·(H2O)3}n (1, H4BPTC = 1,1′- biphenyl-2,2′,6,6′-tetracarboxylic acid, tby = 2,2′:6,2′′-terpyridine) has been synthesized by the hydrothermal reaction, and its structure was determined by X-ray diffraction and characterized by elemental analysis, IR spectrum and thermogravimetric analysis. The crystal is of monoclinic, space group P21/c with a = 10.971(2), b = 20.776(4), c = 14.332(3) , β = 109.25(3)o, MnC31H27N3O12, Mr = 688.50, V = 3084.1(10) 3, Dc = 1.483 g/cm3, F(000) = 1420, μ = 0.498 mm-1, S = 1.066 and Z = 4. The final refinement gave R = 0.0447 and wR = 0.1103 for 5107 observed reflections with I > 2σ(I). The title complex has a {[Mn(H2BPTC)(tpy)(H2O)]}n chain structure, and the hydrogen bonding interactions make it more stable. Each chain is further connected to the adjacent ones through π···π, C-H···π and rich hydrogen bonds to form a metal-organic coordination polymer.     

桥梁结构水下基础表观缺陷立体视觉检测试验

针对桥梁结构水下基础表观缺陷检测实际需求,提出立体视觉表观缺陷检测方法。采用SIFT算法完成表观缺陷图像特征提取与匹配,选用MATLAB编译立体视觉表观缺陷检测评定软件,集成桥梁结构水下基础表观缺陷立体视觉检测系统。使用该系统在实验室环境完成水及空气两种环境下混凝土剥落、裂缝及楔槽三种缺陷的检测对比试验,得到每种混凝土试块表观缺陷在不同环境下的检测结果。试验结果表明,立体视觉表观缺陷检测方法能准确评定表观缺陷几何尺寸,从而验证了该方法用于桥梁结构水下基础表观缺陷评定的实用性及可行性。     

Raman Spectrum of Epitaxial Graphene Grown on Ion Beam Illuminated 6H-SiC （0001）

Patterning SiC substrates with focused ion beam for growth of confined graphene nanostructures is interesting for fabrication of graphene devices. However, by imposing an ion beam, the morphology of illuminated SiC substrate surface is inevitably damaged, which imposes significant effects on the subsequent growth of graphene. By using confocal Raman spectroscopy, we investigate the effects of ion beam illumination on the quality of graphene layers that are grown on 6H-SiC （0001） substrates with two different growth methods. With the first method, the 6H-SiC （0001） substrate is flash annealed in ultra-high vacuum. Prominent defects in graphene grown on illuminated areas are revealed by the emergence of Raman D peak. Significant changes in D peak intensity are observed with Ga＋ ion fluence as low as 10^5 μm^-2. To eliminate the damage from the ion beam illumination, hydrogen etching is employed in the second growth method, with which prominent improvement in the quality of crystalline graphene is revealed by its Raman features. The defect density is significantly reduced as inferred from the disappearance of D peak. The Raman shift of G peak and 2D peak indicates strain-released graphene layers as grown in such a method. Such results provide essential information for patterning graphene nano-devices.     

香鱼自然放养试验

2002~2003年,在浙江省平阳县岭根溪流进行了香鱼自然放养试验.2002年放养香鱼鱼苗3.5×104尾,回捕率为21.4%,回捕香鱼平均尾重35 g,最大个体150 g;2003年放养香鱼鱼苗4.5×104尾,由于当年夏季罕见高温而致干旱溪水断流,结果不理想.     

基于一类重尾分布的函数型线性回归模型的稳健性估计

假定随机误差分布来自具有重尾特征的scale mixtures of normal分布族,运用贝叶斯方法研究了函数型线性回归模型的稳健性估计,其中模型的响应变量为标量,解释变量为函数型变量.数值模拟结果表明:当响应变量的观测数据存在离群值时,建立的方法得到的模型参数的估计,要优于正态分布假定下的模型参数的估计.