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61.
Yiu-yin Lee 《浙江大学学报(A卷英文版)》2017,18(1):75-82
This paper addresses the effect of leakage on the natural frequencies of a large amplitude vibrating panel backed by a cavity, which has not been considered in many other related studies. The structural-acoustic governing equations are employed to study this nonlinear problem. An elliptical integral method, which was recently developed for the nonlinear panel cavity problem, is introduced here to solve for the structural-acoustics responses. The present results agree reasonably well with those obtained from the classical harmonic balance method. Modal convergences of the nonlinear solutions are performed to verify the proposed method. The effects of vibration amplitude and leakage size are studied and discussed. It is found that (1) the edge leakages in a panel cavity system significantly affect the natural frequency properties, and (2) the edge leakages induce a low frequency acoustic resonance. 相似文献
62.
This paper presents an adaptive strategy for controlling chaotic systems. By employing the phase space reconstruction technique in nonlinear dynamical systems theory, the proposed strategy transforms the nonlinear system into canonical form, and employs a nonlinear observer to estimate the uncertainties and disturbances of the nonlinear system, and then establishes a state-error-like feedback law. The developed control scheme allows chaos control in spite of modeling errors and parametric variations. The effectiveness of the proposed approach has been demonstrated through its applications to two well-known chaotic systems: Duffing oscillator and Rössler chaos. 相似文献
63.
Tenko Raykov Thanos Patelis George A. Marcoulides Chun-Lung Lee 《Structural equation modeling》2016,23(1):111-115
This article outlines an interval estimation procedure that can be used in a 3-level setting to evaluate the proportion of outcome variance attributable to the second level of clustering. The method is useful for examining the necessity of including a possibly omitted intermediate level of nesting in analyses of data from a multilevel study, and represents an informative addendum to current statistical tests of second-level variance. The approach is developed within the framework of latent variable modeling and can be used as an aid in the process of choosing between 2-level and 3-level models in a hierarchical design. The discussed procedure is illustrated with an empirical example. 相似文献
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Many have called for re-examination of the “colorblind” philosophy to which some early educators have, tacitly or explicitly, adhered (e.g. Boutte et al. 2011; Derman-Sparks and Edwards 2010; Husband 2012). It has been argued that, while colorblind approaches may appear to be politically neutral, they actually exacerbate racial oppression. In this article, we advocate for a direct and active approach to raising conversations about race with younger preschool children. Based on the developmental nature of young children’s concepts of self and of other, our focus is on initiating discussions about concrete and observable physical aspects of human diversity associated with race. Young children notice and are curious about differences in skin color, hair texture, and facial features. Because these differences are salient, are accessible, and are of interest to young children they can serve as an effective starting point. We suggest shared reading of high quality illustrated children’s books, incorporating the principles of dialogic reading, as a potent springboard for discussions about race with very young children. Our purpose is to equip children, very early in their schooling, with a color-filled appreciation for and comfort with physical diversity of appearance. On that foundation, children may better proceed on the course of developing anti-racist attitudes. 相似文献
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In Japan, there has been an increased concern about family and community participation in the childs education. Traditionally, the role of parents and community in Japan has been one of support and less one of active involvement in school learning. Since the government commenced education reforms in the last quarter of the 20th century, a more active role for parents and the community in education has been encouraged. These reforms have been inspired by the need to tackle various problems that had arisen, such as the perceived harmful elements of societys preoccupation with academic achievement and the problematic behavior of young people. In this paper, the following issues are examined: (1) education policy and reform measures with regard to parent and community involvement in the childs education; (2) the state of parent and community involvement at the eve of the 20th century. 相似文献
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69.
Marianne?Mansour Andrew?J.?MartinEmail authorView authors OrcID profile Michael?Anderson Robyn?Gibson Gregory?Arief?D.?Liem David?Sudmalis 《The Australian Educational Researcher》2016,43(2):221-244
This study explored the role of student (e.g., age, language background, gender), home (e.g., parent/caregiver education), and school (e.g., school type, size) socio-demographic factors in students’ school (e.g., in-school arts tuition, arts engagement), home (e.g., parent/caregiver–child arts interaction), and community (e.g., arts attendance, arts tuition) arts participation. The sample comprised 1172 elementary and secondary school students from 15 schools. Findings revealed that student and home socio-demographic factors were the most salient in predicting arts participation across school, home, and community contexts. Age, gender, and prior achievement were the key student socio-demographic factors, while parent/caregiver education and occupation were also associated with students’ arts participation. Implications for practice and intervention pertinent to young people’s arts participation are discussed. 相似文献
70.
This paper reports research on the effects of variations in injection velocity and permeability on the heat transfer and flow
through a highly porous medium between two horizontal parallel plates situated at constant distance with constant suction
by the upper plate. Due to this type of variation in injection velocity and in permeability the flow becomes three dimensional.
The governing equations are solved by adopting complex variable notations to obtain the expressions for the velocity and temperature
field. The skin-friction along the main flow direction and rate of heat transfer are discussed with the help of graphs. 相似文献