Large amplitude free vibration of a flexible panel coupled with a leaking cavity

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.     

‘Research as dialogue’ and cross-cultural consultations: confronting relations of power

In this paper, we discuss methodological issues that emerged as we worked through a small empirical research project, ‘Engaging Aboriginal students in education through community empowerment’. Recent national policy statements (see, for example, MCEETYA 2000, NBEET 1995) argue the importance of education/research that keeps the locus of control within the Aboriginal community as a means to further the goal of self-determination and improve educational outcomes. In keeping with these recommendations, our project aimed to challenge assimilationist frameworks and sought to ‘empower’ members of the local Aboriginal community through participation in the project.     

Fostering scientific understanding and epistemic beliefs through judgments of promisingness

The evaluation of promisingness is central to knowledge building and knowledge creation but remains largely unexplored. As part of a design-based research program to support promisingness judgments, the present study implemented an intervention in a sixth grade science class, with the goal of exploring the potential of promisingness judgments to foster scientific understanding and epistemic beliefs. Aided by a Promising Ideas Tool and pedagogical supports designed for this intervention, students explored the concept of promisingness, judged the promisingness of their community ideas, and engaged in iterative cycles of idea refinement. Results indicated that students were capable of improving their understanding of promisingness and making promisingness judgments deemed sensible by domain experts. The conceptual understanding and epistemic beliefs displayed by students improved over the course of the intervention, and such improvement happened in tandem with students’ understanding of promisingness. The implications of this exploratory study and future research are discussed.     

建立全球合作伙伴关系

要让人们赶上时代的步伐,就要对他们进行及时的、非常切实有用的培训,有可能就给他们很短的一点时间的培训,如果他们有时间的话,就可以马     

The Relationship between Attitudes, Knowledge, and Demographic Variables of High School Teachers Regarding Food Irradiation

ABSTRACT:  The purpose of this study was to use a validated instrument to determine the attitudes and knowledge of high school teachers regarding food irradiation, and to determine the correlations among their knowledge and attitudes and certain demographic variables. Knowledge and attitudes about food irradiation were measured in selected high school family and consumer sciences teachers ( n = 121) who taught Food and Nutrition, Food Science and Technology, and/or Food Production Management and Services, via a 24-item instrument with 6 factors. Results revealed these teachers held neutral to positive attitudes about the safety of irradiated foods, their perception of the risk of foodborne illness, and learning about food irradiation, and neutral to negative perceptions of their understanding of food irradiation and their competence to teach about it. These teachers had a moderate knowledge base regarding food irradiation. Teachers' attitudes regarding the safety of food irradiation were positively correlated with their perceived understanding of food irradiation, actual knowledge of it, and competence to teach about it. Their perceived understanding of food irradiation was positively correlated with competence to teach about it, knowledge, and attitudes toward the safety of food irradiation. The only demographic variable correlated with knowledge or attitudes was teachers' previous food irradiation educational experiences. These data suggest the importance of education for family and consumer sciences teachers concerning food irradiation.     

汇率干预中的多点自由边值问题的数值计算方法

1IntroductionIt is i mportant for the economic development of acountry to maintain the stabilization of exchange rate,so the intervention of exchange rate has become thetopic of the main concerns of the economic and math-ematical circles[1-5].To maintain the stabilization ofexchange rate,many countries use target zone re-gi mes,that is,the central banks intervene in the for-eign exchange market such that the exchange ratestays within the interval[a,b].There are fixed costand cost proportional …     

Temperament, emotion, and social interactive behavior in the strange situation: a component process analysis of attachment system functioning

This study examines the contributions of temperamentally and nontemperamentally based emotional reactions to the organization of social interactive behavior within the Strange Situation to better understand the emotional underpinnings of attachment system functioning. At 12 1/2 and 19 1/2 months, temperamental fear (assessed via maternal report) was related to independent per-episode dimensions of social interactive and distress behavior. Fear was moderately correlated with both distress and interactive dimensions at each age. Path-analytic models revealed that temperamental fear had direct effects on interactive behavior and also indirect effects mediated by preceding distress reactions. However, residualized measures of "context-specific" distress (with temperamental variance removed) were still highly consistent across Strange Situation episodes and also significantly predicted subsequent social interactive behavior; furthermore, stable distress reactions from 12 1/2 to 19 1/2 months significantly predicted concurrent stability in social interactive behavior. We discuss likely sources of "context-specific" emotional influences on Strange Situation behavior and also age-related differences in these findings.     

Investigation of iodine concentration in salt,water and soil along the coast of Zhejiang,China

Objective: We aim to describe the environment iodine concentration in salt, water and soil along Zhejiang Province coast in the China foreland. It will be helpful for us to judge whether this area is insufficient in iodine and universal iodized salt is necessary or not. Methods: We collected iodized salt samples, drinking water samples (tap water in the towns, and well water or spring water in the villages), water samples from different sources (ditches, lakes, rivers) and soil samples through random sampling in June, 2005. Salt, water and soil iodine was detected by arsenic-cerium redox method. Statistical analysis was expressed as mean±SEMby Windows SPSS 13.0. Results: (1) The iodine concentration in salt was 27.9±4.33 mg/kg (n=108). (2) Seventy-five water samples were collected. The water iodine value was 0.6～84.8 μg/L (mean of 11.66 μg/L). The watershed along the Qiantang River has significantly higher iodine content than the water in Lin'an in mountain area (P＜0.01). The iodine content and mean iodine content of tap water, well or spring water and natural water sources were 4.30±2.43 μg/L (n=34), 23.59±27.74 μg/L (n=19)and 12.72±10.72 μg/L (n=22) respectively. This indicated that among environmental water sources, the ditch iodine content was the highest with river water iodine being the lowest (P＜0.01). (3) Soil iodine value was 0.11～2.93 mg/kg (mean of 1.32 mg/kg).Though there was no statistical difference of soil iodine in different districts (P=0.131), soil iodine content correlated positively with water iodine content. Conclusion: Iodine concentration in salt accords with national policy of adding iodine in salt. Foreland has more iodine in water than mountain area. The data reflected that water and soil iodine in foreland area was not high, which suggests universal iodized salt should be necessary. Environment iodine has relatively close association with pollution.