Studies on the Physicochemical Properties, Structure and Antitumor Activity of an Oligosaccharide Homologue SnS-2 from the Root of Scrophularia ningpoensis Hemsl.

Introduction Scrophularia ningpoensis Hemsl. is a well-known traditional Chinese herbal medicine that has been found to possess the abilities of 揷ooling the blood, nourishing the kidney, purging the schenic fire, clearing away heat and toxic material, profiting the throat?1 In the litera-ture, its components were also reported including alka-loid, flavone glycoside, sterol, amino acid, fatty acid, naphtha, carotene and trace elements.1 At present some other components, mainly small molecular…     

Preparation and Visible Light Photocatalytic Activity for Photocatalyst of Permeable Glass Membrane/TiO2 Doped with Co

The photocatalyst of permeable glass membrane/TiO2 doped with Co （permeable glass membrane/TiO2 doped with Co） is prepared by the sol-gel method. The morphology and phase of the samples are determined by the field emission scanning electron microscopy （FESEM） and x-ray diffraction experiment, respectively. The photo- catalytic results show that the photocatalyst is sensitive to the visible light and exhibits excellent photocatalytic activity of photodegradation methylene blue. The photocatalytic mechanism is also discussed.     

H型风力机叶片桨矩角影响的数值分析

本文采用笛卡尔动网格数值模拟方法,研究叶片桨距角变化对三叶片H型垂直轴风力机气动性能和二维非定常黏性流场的影响。采用SST湍流模型,桨矩角变化范围为-12°-2°,叶尖速比为1.86,2.15,2.27。比较了不同尖速比时风能利用系数随桨矩角的变化,揭示了桨矩角不同时单个叶片和风力机总载荷沿周向的变化规律,讨论了一个旋转周期内桨矩角变化对二维非定常涡量场的影响。     

以“全反射”为例谈教学设计的“关注点”

以"全反射"一节为例,分析、讨论了教学设计的10个"关注点",提出了"高效课堂从有效设计开始"的观点.     

脱氧核糖核酸(DNA)中鸟嘌呤和腺嘌呤阳极差分脉冲伏安法同时测定

本文采用阳极差分脉冲伏安法同时测定微量DNA水解碱基鸟嘌呤和腺嘌呤的含量,从而建立了一种能对微量DNA进行快速测定G+C/A+T值的方法。本方法比层析分离后紫外吸收法灵敏度约高二个数量级,测定时间缩短到一小时半左右。经用德国小牛胸腺标准DNA进行实验,证明本方法准确可靠;并测定了大肠杆菌、棉铃虫等六种DNA的G+C/A+T值。     

把课堂还给学生——以一节解三角形习题课为例

如何让我们的数学课堂变得精彩?关键还得从教师做起,从课堂做起,把课堂还给学生,让学生大胆地去尝试,去思考,去表达,面对课堂上学生提出的新问题,教师要给予鼓励与支持,本文以一节解三角形习题课为例进行说明.     

集合虽简单 交汇试题难

当集合与其他知识交汇时,试题往往变得难以解决,在试卷讲评课上,笔者选取几道集合与其他知识交汇的试题,带领同学们一探究竟,结果课堂精彩纷呈,本文介绍课堂实录及教学思考.