取代三联吡啶光度法测定铬(Ⅵ)

研究了 6 ,6″—二甲基— 4′—苯基 - 2 ,2′ :6′ ,2″—三联吡啶 (TPY)与Cr(Ⅵ )的显色反应。在pH5 .0 6 .2的HAc -NaAc介质中 ,Cr(Ⅵ )与该试剂形成稳定的橙色络合物 ,其吸收峰波长λmax=36 7nm ,表观摩尔吸光系数为 1.72× 10 5L(mol·cm) -1,Cr(Ⅵ )浓度在 1.3～ 76 μg/L内服从比尔定律。精密度和准确度实验结果表明 ,该方法准确 ,可用于环境水及电镀水中铬 (Ⅵ )的测定     

轴不对称联芳香化合物的研究5.(+)-和(-)-9,9’-联菲-10,10’-二甲酸的合成

文中讨论了(+)-和(-)-9,9′-联菲-10,10′-二甲酸的合成路线设计.选出了最佳的合成路线,其中关键中间体是10-溴-9-菲甲酸.其合成方法是在碱性条件下使9-菲甲酸与溴溴化钾—DMF发生10-位溴代反应,产率很好.研究中也探讨了U11mann反应的条件。合成所得的光学纯的(+)-和(-)-9,9′-联菲-10,10′-二甲酸在碱性和中性条件下均难以消旋,说明它有僵硬的轴不对称结构.     

欧共体竞争法的实施机制及对我国的启示

欧盟理事会第1/2003号条例取代了1962年第17号条例,废除了原有的事前申报制度,实现了欧共体竞争法实施的非集权化,加强了欧盟委员会的调查权,由此确立了“非集权”的竞争法实施机制①。在新机制下,委员会负责制定和发展欧共体的竞争政策,实施欧共体竞争法的任务由各成员国承担。作为世界上最先进的竞争法体系之一,欧共体竞争法的最新发展对我国竞争法制的确立有重要的借鉴意义。     

青海省入境旅游市场的态势分析及预测研究

随着中国入境旅游的迅速发展,青海省的入境旅游呈现出不同的态势。本文从海外游客客源地、客源国等方面对其进行了深入的分析,在此基础上进行了预测,并提出了可行性建议。     

基于股价预测的泛证券投资组合策略

本文基于期望效用最大化和L₁-中位数估计研究了在线投资组合选择问题。与EG（Exponential Gradient）策略仅利用单期价格信息估计价格趋势不同,本文将利用多期价格信息估计价格趋势,以提高在线策略的性能。首先,基于多期价格数据,利用L₁-中位数估计得到预期价格趋势。然后,通过期望效用最大化,提出一个新的具有线型时间复杂度的在线策略,EGLM（Exponential Gradient via L₁-Median）。并通过相对熵函数定义资产权重向量的距离,进而证明了EGLM策略具有泛证券投资组合性质。最后,利用国内外6个证券市场的历史数据进行实证分析,结果表明相较于UP（Universal Portfolio）策略和EG策略,EGLM策略有更好的竞争性能。     

危机事件中的网络视频传播与话语分析

随着网络视频的兴起,网络传播进入视频时代：对央视网和优酷网“甲型H1N1流感”议题的网络视频进行对比研究发现,在视频节目来源、话语平台的影响力和话语影响力以及话语呈现和对话机制方面,网络视频官方话语与民间话语的呈现都存在显著差异和一定规律。更为重要的是,网络视频传播在危机事件中的作用日益显著。     

A variable-neighbourhood search algorithm for finding optimal run orders in the presence of serial correlation

The responses obtained from response surface designs that are run sequentially often exhibit serial correlation or time trends. The order in which the runs of the design are performed then has an impact on the precision of the parameter estimators. This article proposes the use of a variable-neighbourhood search algorithm to compute run orders that guarantee a precise estimation of the effects of the experimental factors. The importance of using good run orders is demonstrated by seeking D-optimal run orders for a central composite design in the presence of an AR(1) autocorrelation pattern.     

Nonparametric control charts based on runs and Wilcoxon-type rank-sum statistics

In this article, we introduce three new distribution-free Shewhart-type control charts that exploit run and Wilcoxon-type rank-sum statistics to detect possible shifts of a monitored process. Exact formulae for the alarm rate, the run length distribution, and the average run length (ARL) are all derived. A key advantage of these charts is that, due to their nonparametric nature, the false alarm rate (FAR) and in-control run length distribution is the same for all continuous process distributions. Tables are provided for the implementation of the charts for some typical FAR values. Furthermore, a numerical study carried out reveals that the new charts are quite flexible and efficient in detecting shifts to Lehmann-type out-of-control situations.     

盖尔达维的中间主义思想研究

作为当代阿拉伯-伊斯兰世界的主流思潮之一,伊斯兰“中间主义”认为,伊斯兰文明的首要信息是中正与和平,伊斯兰教反对各种形式的极端主义和恐怖主义,不同文明间应开展平等对话与交流,不同民族和国家间的友好交往是人类共同发展和世界持久和平的基础。卡塔尔大学教授尤苏夫·盖尔达维是这一思潮的重要代表人物之一,本文对其主要思想作了简要介绍,并指出他的中正、中和思想对于维护阿拉伯民族的团结、促进各国人民相互理解和世界和平事业,具有重要的现实意义。     

The Frisch–Waugh–Lovell theorem for the lasso and the ridge regression

The Frisch–Waugh–Lovell (FWL) (partitioned regression) theorem is essential in regression analysis. This is partly because it is quite useful to derive theoretical results. The lasso regression and the ridge regression, both of which are penalized least-squares regressions, have become popular statistical techniques. This article describes that the FWL theorem remains valid for these penalized least-squares regressions. More precisely, we demonstrate that the covariates corresponding to unpenalized regression parameters in these penalized least-squares regression can be projected out. Some other results related to the FWL theorem in such penalized least-squares regressions are also presented.