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求解一阶线性非齐次微分方程常用常数变异法,同学们学习的时候不是太理解为什么。可以从另一个角度,用学过的全微分方程的有关知识推导一阶线性非齐次微分方程的通解。既让学生掌握了新知识——常数变异法,又让学生复习了旧知识——全微分方程。从而达到“温故知新”的效果。以此为例,希望学习高等数学的时候可以做到“温故知新”。 相似文献
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Using high resolution electron microscopy, the structure of [100] tilt boundary with misorientation of 1.2° in YBa2Cu3O7-δ has been determined. The boundary is shown to consist of an array of partial dis-locations, These partials result from the dissociation of a perfect dislocation with a Burgers vector [0, 0, c] on its climb plane according to the reaction, b→b1+b2+b1+b2+b1+b2. Here b=[00c], b1=[O,b/2, c/6} (or [a/2, 0, c/6] ). b2=[0, -b/2. c/6] (or[ -a/2, 0, c/6] ). The spacing between the perfect dislocations satisfies the Read-Shockley formula. There exist no amorphous phases in the boundary region. 相似文献
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冯端,祖籍浙江绍兴,1923年4月27日生于江苏苏州.祖父年轻时赴江西谋生,中年早逝.父亲冯祖培,清末科举考试中曾以陪考而中试,但不久因废科举而未获功名,中年投身仕途.他擅书法;工诗词,依然一介书生.母亲严素卿,也是寄寓安徽的绍兴人.他们生有三子一女.冯端长兄冯焕,1947年赴美国功读电机工程,获博士学位后定居美国,为通用电器公司研究发展中心高级工程师,现已退休,为东南大学名誉教授;姐姐冯慧?... 相似文献
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随着科技的发展和进步,课堂教室的辅助仪器会更加趋于便捷化和自动化。该文所介绍的一种可移动式自动收作业机可以自由在教室内移动收取作业,按照序号排列学生的作业并对作业打包,为任课教师和课代表收取作业和清点数目提供很大便利。 相似文献
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Using high resolution electron microscopy, the structure of [100] tilt boundary with misorientation of 1.2° in YBa2Cu3O7-δ has been determined. The boundary is shown to consist of an array of partial dis-locations, These partials result from the dissociation of a perfect dislocation with a Burgers vector [0, 0, c] on its climb plane according to the reaction, b→b1+b2+b1+b2+b1+b2. Here b=[00c], b1=[O,b/2, c/6} (or [a/2, 0, c/6] ). b2=[0, -b/2. c/6] (or[ -a/2, 0, c/6] ). The spacing between the perfect dislocations satisfies the Read-Shockley formula. There exist no amorphous phases in the boundary region. 相似文献