干燥温度对鲜西洋参糖类成分的影响

本研究采用26℃，32℃，38℃，44℃和50℃等5个恒定温度分别干燥西洋参，在干燥过程中每两天取样一次，测定淀粉和还原糖含量，以研究干燥温度对鲜西洋参糖类成分的影响。结果表明：用5个恒定（26℃，32℃，38℃，44℃和50℃）干燥西洋参，粗淀粉和还原糖含量总体上呈下降趋势；粗淀粉和还原糖的变化趋势相反；38℃处理整个干燥日程还原糖含量均最高，与其他处理相比差异极显著（P＜0．01），而且淀粉含量相应地较其他处理低。     

曲靖市初中语文课果改成效的实证研究调查报告

随着语文新课程改革的深入开展,对于课改中存在问题及成效的关注越来越成为研究的热点.在实证调查研究的基础上,分析了曲靖市初中语文新课程改革在课改理念、课程评价、教师行为、教材等方面存在的问题和实效,并针对相关问题提出了可资借鉴的建议和意见.     

腾格里沙漠西南缘固定沙丘水分动态与水分势能变化特征研究

１９９３～１９９４年在腾格里沙漠西南缘邓马营湖北部一固定沙丘上设置观测点，采用中子仪、负压计逐日定时分层测定沙丘０～１７５ｃｍ深度含水量和水分势能．对实测资料加以分析表明：（１）沙丘水分深度分布剖面可划分为４层；表面干沙层、水分强烈变化层、低含水量缓变层、高含水量变化层；（２）依据水分势能变化特征，势能剖面可分为变化活跃区、频变区、突变区和缓变区．同时，结合沙丘水分时间变化特征，得出结论：水分势能与水分动态存在较好的对应性．从而表明由势能观点研究沙丘水分动态的可行性和正确性，为沙丘水分运移机理及运移方程的研究提供了一定的科学依据．     

催化剂颗粒的粒径对渣油加氢反应的影响

利用浆态床渣油加氢工艺对不同直径的催化剂颗粒进行活性评价，评价结果显示催化剂在直径较小或较大时均不利于杂质的脱除。利用XRD、BET、TG/DSC、TPO、SEM/EDS等表征手段对催化剂活性及稳定性进行研究，结果表明在催化剂表面及孔道中，渣油中沥青、含金属的卟啉结构等大分子生成焦炭、金属硫化物等附聚物以及沉积物是影响催化剂性能的主要原因。综合考虑所有杂质的脱除率可知，直径为1.2mm时催化剂的总体性能最好。     

图的电阻距离的一个下界可达性

连通图中任意2个顶点之间的电阻距离定义为将图中每条边用单位电阻代替后所得电网络中这2个节点之间的有效电阻.应用Rayleigh单调性法则等电网络理论以及网孔分析法,本文刻画了图的电阻距离的一个下界可达的充要条件.     

Preface

正It is well known that the increases in atmospheric CO2and CH4(long-lived greenhouse gases;GHGs)owing to anthropogenic activity are the dominant processes driving global climate change.Space-based measurements of GHGs with high precision,resolution,and global coverage are urgently needed to characterize the geographic distribution of their sources and sinks,and to quantify their roles in the atmospheric CO2budget.Over the past 10 years,the European Space Agency(ESA),the National Aeronautics     

生物技术的应用研究与展望

介绍了基因治疗极其广泛的应用前景,回顾了植物基因工程技术开发、应用成果以及海洋生物技术的开发情况,阐述了彩色棉花等作物的培育及尚待解决的问题。     

恩施州水环境承载力研究

从水资源对社会经济发展的作用出发,采用向量模法对恩施州近5年的水环境承载力进行分析评价.研究结果表明,2007-2011年恩施州水环境承载力呈增加趋势,其值由2007年的0.302增加到2011年的0.6056,年平均增长率为19%,说明恩施州的水环境承载力能够满足社会经济发展的需要.     

Theoretical advances of the structures and catalytic activities of small-sized gold nanoclusters

Gold nanoclusters exhibit extraordinary catalytic activities,but the dominating factor is still unclear due to the complexity of the structures.In this review,we briefly summarized the recent theoretical progress on their structures and catalytic activities.Combining the experimental and theoretical efforts,the structures of small-sized gold clusters have been explored systematically.Based on the determined structures,factors that influence the catalytic capabilities of small-sized gold clusters(Au_(16)-Au_(35))are studied using CO oxidation asa probe.The preadsorption energies of CO and O_2are found strongly correlated with catalytic activities,which could be affected by the clusters'geometries,sizes,and charge distributions.In addition,the presence of water could significantly lower the activation energy barrier of O_2 dissociation to enhance the clusters'catalytic activities.     

Maximum likelihood estimator of the parameter for a continuous one-parameter exponential family under the optimal ranked set sampling

This paper studies a maximum likelihood estimator (MLE) of the parameter for a continuous one-parameter exponential family under ranked set sampling (RSS). The authors first find the optimal RSS according to the character of the family, viz, arrange the RSS based on quasi complete and sufficient statistic of independent and identically distributed (iid) samples. Then under this RSS, some sufficient conditions for the existence and uniqueness of the MLE, which are easily used in practice, are obtained. Using these conditions, the existence and uniqueness of the MLEs of the parameters for some usual distributions in this family are proved. Numerical simulations for these distributions fully support the result from the above two step optimizations of the sampling and the estimation method.