排序方式: 共有87条查询结果,搜索用时 15 毫秒
1.
INTRODUCTION Since the phenomenon of piezoelectricity in natural crystals was discovered in 1880, it has been applied in many fields, such as smart structure, sensing devices and active control, because of its special properties. Combining electrical behavior with mechanical deformation is the special property which attracted great interest of researchers. Many models have been developed for studying piezoelec- tric effects. Dunn and Wienecke (1996) used Green’s functions for transverse… 相似文献
2.
李荣玲 《临沧师范高等专科学校学报》2007,(4):88-90
化归思想贯穿于解析几何全部内容,是蕴涵在解析几何知识中的主要数学思想方法。文章拟从一节解析几何课为切入点对加强化归思想方法教学,用化归思想统领、整合教材内容作了一些尝试。 相似文献
3.
The present study examined the effectiveness of three instructional treatments which had different combinations of mathematical elements regarding 2-dimensional (2-D) geometry and area measurement for developing 4th-grade children's understanding of the formulas for area measurement and their ability to solve area measurement problems. Participants were 120 fourth graders. The results showed that the enriched curriculum, involving the geometry motions and area measurement connections effectively facilitated children's mathematical judgments and explanations demanding high-level conceptual understanding. The instructional curricula accentuating only 2-D geometry or numerical calculations for area measurement did not exhibit such effectiveness. Interview data revealed that the geometric operations of superimposition, decomposition, re-composition as well as the concept of congruence were deemed essential by children for the conceptualization of the formulas for area measurement. 相似文献
4.
汉语中一些常用的学科名称词所表达的概念大部分是外来的,但其本身是否外来词,值得仔细研究。这些词包括数学、几何、物理、化学、逻辑学、经济学等。 相似文献
5.
6.
采用质点几何学的方法证明了欧拉线定理,并将其推广到高维以及位似形的情况,并讨论了四面体的外心、内心及奈格尔点. 相似文献
7.
The symplectic approach proposed and developed by Zhong et al. in 1990s for elasticity problems is a rational analytical method, in which ample experience is not needed as in the conventional semi-inverse method. In the symplectic space, elasticity problems can be solved using the method of separation of variables along with the eigenfunction expansion technique, as in traditional Fourier analysis. The eigensolutions include those corresponding to zero and nonzero eigenvalues. The latter group can be further divided into α-and β-sets. This paper reformulates the form of β-set eigensolutions to achieve the stability of numerical calculation, which is very important to obtain accurate results within the symplectic frame. An example is finally given and numerical results are compared and discussed. 相似文献
8.
9.
Konstantinos A. Sdrolias Triandafillos A. Triandafillidis 《Educational Studies in Mathematics》2008,67(2):159-169
Students mainly perceive the transition to secondary school as an opportunity to start their school career anew. Reality often
proves them wrong, especially in the case of mathematics. In our paper, we briefly discuss children’s transition to secondary
school as both an opportunity and a problem, with reference to the Greek context. In discussions about the transition to secondary
school and its effect on the teaching and learning of mathematics, primary and secondary school teachers in Greece often depict
school mathematics as a “chain” of concepts and procedures. With this metaphor as our reference point, we discuss how ideologies
about the teaching of mathematics are enacted in both school levels. We will base our discussion on the analysis of extracts
taken from dialogues in primary and secondary school mathematics classrooms in Greece. In our analysis, we employ a Peircean
view of semiotics in an attempt to conceptualize students’ rushed introduction to rigor in justifying mathematical statements
in secondary school. These extracts are part of a longitudinal study that aimed, on the one hand, to pinpoint discontinuities
and continuities in the teaching of geometry between primary and secondary schools and, on the other, to investigate whether
a set of curriculum material that we designed could serve as a link in the teaching of geometry between the two school levels. 相似文献
10.
利用辛几何构作了一个non-Cartesion认证码,计算了它的参数;当编码规则按等概率分布选取时,求出了模仿攻击和替换攻击成功的概率. 相似文献