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关键词： Natural   Synthetic humic substances   Fluorescence quenching   Pyrene   Surface tension  

摘要： The direct and indirect interaction mechanisms of pyrene with: (i) various molecular weight fractions of a synthetic humic-like substance (SyHA) and (ii) extracts of natural humic acids (NHA) from Moselle River suspended matter were investigated using quenching fluorescence and surface tension measurements. Humic materials were characterized in a previous study. The Stern-Volmer associative constants were determined from the quenching technique. Surface tension measurements revealed an increase in surface activity as a function of concentration for each humic fraction independently of the pyrene presence in solution, even during the formation of humic micelles. The results obtained suggest the possibility of specific intermolecular interactions occurring during pyrene entrapment within humic acids. In addition, we show that molecular weight. aliphatic chains (especially those containing nitrogen groups) and number of acidic groups are determinant characteristics for pollutant entrapment capacity at concentrations below the critical micellar concentration (CMC) of humic substances. (C) 2010 Elsevier Ltd. All rights reserved.

关键词： 检验   质量   质量检验   监督职能   鉴别   界限值   预防极限   抽样检验   科技含量  

摘要： 现代的质量检验不仅赋予了企业强有力的鉴别、监督等职能。同时,在企业的整个产品生产、形成和实现的全过程中,起到重要的质量保证作用。产品的质量检验水平直接代表着企业的科技含量。质量检验工作是企业的决策者界定实现项目的前沿。

关键词： 浙江民营企业   GDP   进出口   协整分析   对策  

摘要： 民营企业是浙江经济的亮点,其对外贸易是浙江经济发展的主要推动力,因此研究民营企业外贸对浙江经济的作用机理很有理论价值和实践意义。文章利用ADF检验对变量平稳性进行考察,应用协整方法和LM检验法对变量的长期均衡进行分析,应用Granger因果检验法对变量的因果关系进行研究,应用误差修正模型得到变量之间的长期稳定关系。文章最终提出了相应的对策和建议。

关键词： 纺锤体检验点   有丝分裂   动粒  

摘要： 细胞周期的分为四个时期,每个时期之间的转换受到细胞内严格的调控,细胞周期检验点的作用主要是调节细胞周期的转换,主要包括DNA损伤检验点、DNA复制检验点和纺锤体检验点等细胞周期检验点。纺锤体检验点监控着染色体在赤道板的队列和向纺锤体两极的分离,确保动粒-微管的粘附和有丝分裂器的完整,使所有的染色体都置于赤道板并双极定向后才进入后期,保证遗传物质均等地分配给两个子代细胞。当纺锤体微管与染色体错误连接或者纺锤体组装出现错误时,纺锤体检验点被激活,抑制细胞周期进程。本文主要介绍纺锤体检验点的组成成分及作用的基本机制。

关键词： 劳动合同关系   书面合同   用人单位   延长工作时间   工程进度款   安装项目   书面劳动合同   劳动报酬   劳动行政部门   典型案例分析  

摘要： 本案详情河北A公司系成立于1999年10月的一家企业,2008年9月,该公司中标该市博物馆楼宇智能弱电安装项目,遂从该市所属县区等地招来共计15名民工进行工程中的装修部分施工,从2008年9月3日开始施工。A公司和15名民工都没有签订具体的书面合同。工程开始之后的三个月,由于建设方工程进度款出现问题,A公司从2008年12月份未再发放工资。

关键词： 硬度测试:强度   高温   金相  

摘要： T91为美国研发的合金结构钢钢管牌号,主要用于制造大型发电机机组的过热器、再热器,相当于我国GB5310标准中的10Cr9Mo1VNb,本文介绍了在缺乏材料金相显微组织评级标准的情况下,硬度测试可作为该材料性能的辅助评定手段。

关键词： 出口退税   向量自回归模型   协整分析   脉冲响应函数   方差分解  

摘要： 文章在建立向量自回归模型(VAR)的基础上进行协整分析,考察出口退税对出口的激励作用,并分析其与外部需求对中国出口作用的差异,同时利用脉冲响应函数与方差分解探讨其中的动态特征。研究结果显示,出口退税、外部需求和出口之间存在长期均衡的关系,以弹性系数来看出口退税对出口的长期促进作用低于外部需求。脉冲响应函数与方差分解的结果表明,就短期而言出口退税的激励作用较为显著,而长期来看则外部需求对出口的影响力较大。针对上述结论文章给出了相应的政策建议。

关键词： Classification   LC   Two-dimensional chromatography  

摘要： Comprehensive two-dimensional LC (LC x LC) is a powerful tool for analysis of complex biological samples. With its multidimensional separation power and increased peak capacity, LC x LC generates information-rich, but complex, chromatograms, which require advanced data analysis to produce useful information. An important analytical challenge is to classify samples on the basis of chromatographic features, e.g., to extract and utilize biomarkers indicative of health conditions, such as disease or response to therapy. This study presents a new approach to extract comprehensive non-target chromatographic features from a set of LC x LC chromatograms for sample classification. Experimental results with urine samples indicate that the chromatographic features generated by this approach can be used to effectively classify samples. Based on the extracted features, a support vector machine successfully classified urine samples by individual, before/after procedure, and concentration with leave-one-out and replicate K-fold cross-validation. The new method for comprehensive chromatographic feature analysis of LC x LC separations provides a potentially powerful tool for classifying complex biological samples.

关键词： Support Vector Machine   Feature Selection   Tumor Type   Prediction Accuracy   Training Sample  

摘要： Background: The use of gene expression profiling for the classification of human cancer tumors has been widely investigated. Previous studies were successful in distinguishing several tumor types in binary problems. As there are over a hundred types of cancers, and potentially even more subtypes, it is essential to develop multi-category methodologies for molecular classification for any meaningful practical application. Results: A jackknife-based supervised learning method called paired-samples test algorithm (PST), coupled with a binary classification model based on linear regression, was proposed and applied to two well known and challenging datasets consisting of 14 (GCM dataset) and 9 (NC160 dataset) tumor types. The results showed that the proposed method improved the prediction accuracy of the test samples for the GCM dataset, especially when t-statistic was used in the primary feature selection. For the NCI60 dataset, the application of PST improved prediction accuracy when the numbers of used genes were relatively small (100 or 200). These improvements made the binary classification method more robust to the gene selection mechanism and the size of genes to be used. The overall prediction accuracies were competitive in comparison to the most accurate results obtained by several previous studies on the same datasets and with other methods. Furthermore, the relative confidence R(T) provided a unique insight into the sources of the uncertainty shown in the statistical classification and the potential variants within the same tumor type. Conclusion: We proposed a novel bagging method for the classification and uncertainty assessment of multi-category tumor samples using gene expression information. The strengths were demonstrated in the application to two bench datasets.