空中课堂的“双师模式”线上教学实践研究——以“几何专题复习课”为例

近年来,线上教学发展迅速,笔者以“几何专题复习课”为例,阐明基于空中课堂的“双师模式”线上教学所发挥的特有优势,并尝试通过建立“基本教学活动模块”这一模型,将由“巩固基础”“深化方法”“拓展反思”这三个维度交织而成的“模块”充填、渗透到整个“空中课堂”中,形成学习效益最大化的“双师模式”线上教学活动.

中考几何专题复习如何提高效率

几何是初中数学的重要内容，而中考几何复习却是个难题，几何专题复习效率的高低直接影响着数学整体复习的效率。高效的课堂教学模式是保证高效复习效果的前提，利用高效课堂教学，可以有效指导几何专题的复习。

几何专题复习课如何上出“过程”味?

几何专题复习课如何体现"专题"的价值,教师在备课过程可以从挖掘一道具有代表性的题目开始,将它蕴含的几何要点、几何方法、几何基本图形通过层层铺设,步步逼近,完整且紧密地呈现在课堂,让学生不仅会解这道题,而且掌握这类题的解法,并能引发学生共鸣,启发学生的数学思考。

选编“形异质同”题组,提高专题教学质量——以“探究两条线段之间的数量关系”专题课为例

传统的几何专题课有开放式专题课、数学思想方法的专题课、阅读理解专题课等,近年来以“一图一课”“微专题课”等为代表的专题教学渐渐得到很多教师的实践与研究.这类课型主题聚焦,求深、求透,能有效提升解题教学效率.

四节观摩课的即时思考与再实践

几何复习效率不高是一线数学教师亟待解决的问题．实践证明，借助“活化专题”的方式，能收到良好的复习效果．几何专题复习必须以内化问题情境、活化问题资源、简化教学支架为抓手，采用自主反馈与矫正、自主探究与辨析、自主变式与反思等策略，才能真正提升几何专题复习课的潜能和质量．

Optimization for Maximum Nonlinear Buckling Load and Topics on Imperfection of Latticed Shells

The present paper represents comparison of continuum shells and latticed shells with qualitative analysis. For shells, the mechanical characteristics in the two perpendicular directions are continuous and related to each other, and any change in thickness will result in change in stiffness in any direction. In latticed shells, members are discrete and stiffnesses in two mutually perpendicular directions are discontinuous and independent of each other. Therefore, sensitivity of geometrical imperfection for buckling of latticed shells should be different from that of continuum shells. The author proposes a shape optimization method for maximum buckling load of a latticed shell. A single layer latticed dome is taken as a numerical example, and the results show that the buckling load parameter for full area loading case increases 32.75% compared to that of its initial shape. Furthermore, the numerical example demonstrates that an optimum latticed shell with maximum buckling load, unlike an optimum continuum shell, may not be sensitive to its geometrical imperfection.