排序方式： 共有25条查询结果，搜索用时 23 毫秒
21.
陈勋 《中学生数理化(高中版)》2009,(2):15-17
据报道,近年来垃圾爆炸事件在我国屡有发生。1 997年7月以来,上海120t垃圾船爆炸,湖南、四川垃圾堆爆炸,浙江垃圾山大火,都造成巨大损失,人员惨遭伤亡。原因何在:垃圾堆中的大量的动植物残体,在隔绝空气的情况下,经某些微生 相似文献
22.
<正>大学数学是系统性、抽象性、应用性都很强的基础课。特别对文科学生而言,数学又是开拓思路的一门学科,更是必不可少的公共课,大学数学的主要内容主要为微积分、线性代数和概率论,而如今,面临着课时少,内容多的情况,不少教师为了完成教学任务,不得已对一些必要的定理证明及解题方法进行了缩减,甚至还对一些基本的概念叙述也不够强,从而导致相当一部分学生对所学知识理解不透、记忆不牢,上课时对所学知识点似乎清楚,下课就对学过知识糊里糊涂,有些只掌握了一些简单的计算公式,每做一套题都套用公式,而对一些综合性稍强的题就束手无策。 相似文献
23.
本文从当前的一般的课堂教学分组活动出发,提出以寝室成员为分组单位的“英语寝室”活动的开展,构建“英语寝室”与综合英语课堂教学互动模式,以期提高学生的综合语言运用能力,同时也更好地促进学生自主学习能力的提高。 相似文献
24.
陈勋 《当代教育理论与实践》2021,13(3):19-23
作为"四个自信"的重要组成部分,文化自信是一种更基础、更广泛、更深厚的自信.文化自信的培育是课程思政的重要内容.外国文学文化课程是高校汉语言文学和汉语国际教育专业课程体系的重要组成部分,培育文化自信也是此类课程的题中之义.基于比较文学理论,编者将"文化自信"的基因注入外国文学文化课程的"马工程"教材之中,这给课程思政奠定了基础.在具体的文化自信培育过程中,要发挥教师主导、学生主体作用,改变传统的授课方式,利用现有的优势特色平台,最终达成课程思政的目标. 相似文献
25.
Tea is one of the most popular beverages, consumed by over two thirds of the world's population; but the aluminum accumulation property of tea plant is becoming the focus of many researches because of aluminum's known adverse effect on human health. Investigation of the interactions of catechins with Al3 showed that during the interaction of catechins with Al3 , the UV-vis spectrum of catechins was changed. Absorption of EGCG at 274 nm decreased and increased at 322 nm; EC and C's at 278 nm changed little. The ratio of Al3 to EGCG was 1:1 in pH 5.0 buffer solution; in pH 6.2 buffer solution, the ratio in the Al-EGCG complex was 1:1. Interestingly, while the ratio reached to over 2, after the complex of Al-EGCG started polymerization, the ratio in the polymer was 2:1. In pH 6.2 buffer solution, the complex behavior of C with Al3 was the same as that of EGCG, with a little difference for EC. When the ratio of Al3 to EC was <1, the complex in ratio was 1:2, but, the complex polymerized when the ratio of Al3 to EC was >1. It was found that the ratio of Al3 to EC in the polymer was 1:1. Polymerization of Al-catechin complexes might reduce aluminum absorption in the intestine. Kow value was also employed to study the properties of aluminum species in tea infusion (at gastric and intestine pH condition) and the effect of catechins and tea polyphenols on Kow in buffer solution. Results showed that Kow value rose much higher at the intestine pH than at the gastric pH. Tea polyphenols and catechins could greatly reduce aluminum Kow value in acetic buffer, indicating that these compounds may reduce aluminum absorption during tea intake. 相似文献