电控燃油喷射汽油机加速——滑行组合工况的排放分析

选取三种使用电控燃油喷射汽油机的国产车型,进行突然加速和突然减速工况的HC和CO测试,并结合有关文献的结论,对突然加速和突然减速工况产生大量HC和CO的原因进行了详细的分析;同时阐明解决发动机突然加速和突然减速性能与排放性能的矛盾,仅靠目前的后处理装置是不能彻底实现的,只能依赖于缸内直喷(GDI)技术的早日成熟.     

Teachers’ agency,efficacy, engagement,and emotional resilience during policy innovation implementation

This multiple case study investigated 143 teachers’ responses to focus group questions about their experiences with the simultaneous implementation of three disruptive innovations as part of the U.S. Race-to-the-Top (RTTT) agenda: the Common Core Learning Standards, data-driven instruction, and annual professional performance reviews. We asked: How do teachers describe their experiences implementing these three RTTT innovations? How do teachers describe supports for their adaptation to these innovations? And, for each of these questions, and since the study purposefully included schools with above-predicted student outcomes (i.e. odds-beaters) as well as a comparison set of typically performing schools, we inquired: In what ways do odds-beating school teachers’ experiences differ from their peers in typically performing schools? Guided by an emergent framework that emphasizes the relationships among teacher agency, engagement, efficacy, and emotional resilience and how these vary in different school contexts, findings suggest that district office innovation leadership and resource allocations, school leadership structures and strategies, and collaborative teams and communities of practice vary and relate to teachers’ experiences of innovation implementation. This study advances an empirically-grounded and theoretically rich framework for investigation of teachers’ performance adaptation during policy innovation implementation and suggests implications for future research, policy, and practice.     

CAUSES OF STUDENT ABSENTEEISM IN COMMUNITY COLLEGE CLASSES

In an era of declining college enrollments it is vital to identify potential causes of absenteeism and implement strategies for reducing it. To accomplish this two open‐ended approaches were used to generate a list of reasons for missing social science classes. The combination of these two ultimately led to 51 reasons for missing class that appeared on the Class Attendance Survey in Likert scale format. This survey was shown to have both internal reliability and validity. The dependent variable on the survey was the number of absences reported by each student for the class in which the survey was taken. It was administered in class on or about the last class day by 24 social science professors to 25 classes. This resulted in 402 usable surveys, of which 351 were complete. A factor analysis of the independent variables yielded six factors with eigenvalues greater than 1.0 and factor loadings higher than .50. Four of the six entered a stepwise multiple regression equation. They combined to produce a highly significant F value. In descending order of their beta weights they were labeled “fatigue associated with excessive socializing,” “low attendance incentives,” “irresponsible pursuit of leisure,” and “external responsibilities.” F values for each of the beta weights were significant. Several recommendations for reducing absenteeism were made.