Screening study of transition metal oxide catalysts supported on ceria-modified titania for catalytic oxidation of toluene     

Dan-qing Yu  Yue Liu  Zhong-biao Wu 《浙江大学学报(A卷英文版)》2011,12(6):461-469

Six transition metal oxides were added in ceria-modified titania using a sol-gel method for catalytic oxidation of toluene. An MnOx based catalyst was found to be the most active one, with which toluene could be decomposed completely at 200 °C. The greatest Mn/Ti and molar ratio of the mobile oxygen to the total oxygen concentration, together with a large surface area and a low reduction peak-starting temperature, would result in its best activity in toluene oxidation.  相似文献   

Optimal linear attitude estimators via geometric analysis     

De-ren Gong  Xiao-wei Shao  Wei Li  Deng-ping Duan 《浙江大学学报(A卷英文版)》2011,12(11):873-882

Three optimal linear attitude estimators are proposed for single-point real-time estimation of spacecraft attitude using a geometric approach. The final optimal attitude is represented by modified Rodrigues parameters (MRPs). After introducing incidental right-hand orthogonal coordinates for each pair of measured values, three error vectors are obtained by the use of dot or/and cross products. Corresponding optimality criteria are rigorously quadratic and unconstrained, which do not coincide with Wahba’s constrained criterion. The singularity, which occurs when the principal angle is close to π, can be easily avoided by one proper rotation. Numerical simulations show that the proposed three optimal linear estimators can provide a precision comparable with those complying with the Wahba optimality definition, and have faster computational speed than the famous quaternion estimator (QUEST).  相似文献   

Buckling response of offshore pipelines under combined tension, bending, and external pressure     

Shun-feng Gong  Lin Yuan  Wei-liang Jin 《浙江大学学报(A卷英文版)》2011,12(8):627-636

The buckle and collapse of offshore pipeline subjected to combined actions of tension, bending, and external pressure during deepwater installation has drawn a great deal of attention. Extended from the model initially proposed by Kyriakides and his co-workers, a 2D theoretical model which can successfully account for the case of simultaneous tension, bending, and external pressure is further developed. To confirm the accuracy of this theoretical method, numerical simulations are conducted using a 3D finite element model within the framework of ABAQUS. Excellent agreement between the results validates the effectiveness of this theoretical method. The model is then used to study the effects of several important factors such as load path, material properties, and diameter-to-thickness ratio, etc., on buckling behaviors of the pipes. Based upon parametric studies, a few significant conclusions are drawn, which aims to provide the design guidelines for deepwater pipeline with solid theoretical basis.  相似文献   

Consistency of report card grades and external assessments in a Canadian province     

John A. Ross  Lynn Kostuch 《Educational Assessment, Evaluation and Accountability》2011,23(2):159-180

The study investigated how well report card grades communicate to students and parents that state educational standards are being met, standards that are objectively measured by infrequently administered mandated assessments. Data sources were report card grades and external assessment scores for 2006–09 for Ontario Canada. The information that parents and students received about student performance from report cards and external assessments were similar (r _s  = .47) to the r = .40–.60 range previously reported. Teachers assigned higher grades than external assessments warranted, even after a major source of construct irrelevant variance in report card grades (teacher ratings on multiple scales measuring student effort and school commitment) was controlled. The relationship of grades to assessment scores was robust across genders, school district types (Public versus Catholic) and language (English and French). Agreement of assessments was higher for grade 6 than for grade 3 and for Writing than for Reading or Mathematics. Report cards provided information about students’ future achievement that was accurate and delivered up to 2 years prior to the administration of external assessments. Seventy to 80% of students who reached the provincial achievement standard on one or both prior report cards were successful on the subsequent external assessment, compared to 30–50% of students who failed to meet the report card standard at least once.  相似文献   

Supervision and evaluation: The Wyoming perspective     

Bret G. Range  Susan Scherz  Carleton R. Holt  Suzanne Young 《Educational Assessment, Evaluation and Accountability》2011,23(3):243-265

The intent of this study was to assess the perceptions and actions of Wyoming principals concerning their role in supervising and evaluating teachers. A survey was sent to all 286 principals in the state of Wyoming, of which, 143 returned surveys, a response rate of 50%. Findings suggested that principals utilized supervisory behaviors more often than evaluative behaviors. Elementary principals perceived their evaluative practices as significantly more prevalent than secondary principals. Furthermore, principals indicated that their greatest frustrations in supervising teachers were time, the evaluation instrument, and teachers’ unwillingness to change. Additionally, findings suggested that Wyoming principals utilized classroom walkthroughs because they provided a snapshot of teaching and provided a medium for providing feedback. In regards to developmental supervision, principals indicated that novice teachers received much more supervision than veteran teachers. However, their reported use of differentiated supervision only applied to teacher autonomy concerning professional development goals. Principals reported that teachers had little input concerning the methods by which they were supervised. Finally, a majority of the Wyoming principals felt that improvement plans were effective at changing mediocre teaching behaviors, but 40% were speculative that such plans truly remediated poor teachers.  相似文献   

Curricular innovation in an undergraduate medical program: What is “appropriate” assessment?     

Valerie Ruhe  J. Donald Boudreau 《Educational Assessment, Evaluation and Accountability》2011,23(3):187-200

In post-secondary education, there is a widely-held belief in a “gold standard” for evaluative studies of curricular innovations. In this context, “appropriate” assessment is understood to refer to experimental designs and statistically significant differences in group outcomes. Yet in our evaluative study of a medical undergraduate program, we did not find these concepts to be particularly applicable. Based on our experience, we now feel that it is appropriate to assemble an eclectic mix of scientific findings, show how they have been used for program improvement, and articulate the program’s theoretical rationale and social significance. In the absence of statistically significant differences, this comprehensive argument can be used to justify the deployment of curricular innovations. The same may be true of other educational programs that target hard-to-measure changes in affective domains.  相似文献   

Taking the grading leniency story to the edge. The influence of student, teacher, and course characteristics on student evaluations of teaching in higher education     

Bert Brockx  Pieter Spooren  Dimitri Mortelmans 《Educational Assessment, Evaluation and Accountability》2011,23(4):289-306

The use of student evaluation of teaching (SET) to evaluate and improve teaching is widespread amongst institutions of higher education. Many authors have searched for a conclusive understanding about the influence of student, course, and teacher characteristics on SET. One hotly debated discussion concerns the interpretation of the positive and statistically significant relationship that has been found between course grades and SET scores. In addition to reviewing the literature, the main purpose of the present study is to examine the influence of course grades and other characteristics of students, courses, and teachers on SET. Data from 1244 evaluations were collected using the SET-37 instrument and analyzed by means of cross-classified multilevel models. The results show positive significant relationships between course grades, class attendance, the examination period in which students receive their highest course grades, and the SET score. These relationships, however, are subject to different interpretations. Future research should focus on providing a definitive and empirically supported interpretation for these relationships. In the absence of such an interpretation, it will remain unclear whether these relationships offer proof of the validity of SET or whether they are a biasing factor.  相似文献   

Competence Profile School Management (CPSM) – an inventory for the self-assessment of school leadership     

Stephan Gerhard Huber  Maren Hiltmann 《Educational Assessment, Evaluation and Accountability》2011,23(1):65-88

The professional demands on school leaders have changed drastically and have become highly complex in the last few years. The professionalization of school leaders is high on the agenda. Human resource management includes different aspects of professionalization. One major domain is the preparation, induction and continuous professional development of individual leaders and leadership teams. Another is personnel marketing and selection, which includes the question of attracting capable future leaders and of appointing the right candidates. However in Europe there is a need for standardised tools which provide systematic feedback to professionals interested in assessing their strengths and individual development needs. Suitable instruments are still scarce. The Competence Profile School Management CPSM (German: KompetenzProfil SchulManagement; KPSM) is the first online-based self-assessment in the German language which has been designed to fit the school context and is based on psychometric principles. It offers participants the possibility to reflect their strengths and weaknesses in different requirement areas of school leadership; and to compare their individual results with peers from the school context, thus gaining valuable information on their individual profiles when planning their professional development and careers. After sketching the theoretical and empirical background, this article presents information about the aims and purpose of CPSM, the tool’s development, its test scales and test formats, the results of the pilot study and those of the evaluation study. Then, the further development of the tool in terms of modifications and add-ons are outlined, before, finally, the tool’s contribution to practice and research is discussed.  相似文献   

The Dimensionality of Language Ability in Young Children          下载免费PDF全文

Language  Reading Research Consortium 《Child development》2015,86(6):1948-1965

The purpose of this study was to empirically examine the dimensionality of language ability for young children (4–8 years) from prekindergarten to third grade (n = 915), theorizing that measures of vocabulary and grammar ability will represent a unitary trait across these ages, and to determine whether discourse skills represent an additional source of variance in language ability. Results demonstrated emergent dimensionality of language across development with distinct factors of vocabulary, grammar, and discourse skills by third grade, confirming that discourse skills are an important source of variance in children's language ability and represent an important additional dimension to be accounted for in studying growth in language skills over the course of childhood.  相似文献   

大学体育口号与理念的谱系与解构     

-基于习近平总书记对清华大学的考察刘波  张贝尔  郭振  王松 《南京体育学院学报(社会科学版)》2021,35(5)

体育口号与理念作为体育思想的一种表现形式,是学校开展体育工作的手段之一。本文选取大学体育口号与理念为研究对象,通过文献资料法、问卷调查法和专家访谈法,梳理大学体育口号与理念的历史谱系,以不同时期清华的体育口号与理念为个案分析,以此审视我国大学体育思想的发展脉络。研究指出,从“为祖国健康工作五十年”到“无体育,不清华”体育口号与理念的谱系,价值导入是从“卡里斯马式”到“集体无意识”,呈现出大学体育价值理念的文化记忆。大学体育口号与理念的内涵表现在：从中华民族的救国到建国再到强国的爱国性,从体育运动的强迫到认同再到自发的传承性,从影响范围的区域到国家再到国际的卓越性以及对大学体育的引领性。研究认为,大学体育口号与理念体现了大学体育价值取向的变化以及大学体育思想的继承发扬,是实现“体育的迁移价值”和立德树人的有效手段。  相似文献