Stress analysis of anisotropic thick laminates in cylindrical bending using a semi-analytical approach

Semi-analytical elasticity solutions for bending of angle-ply laminates in cylindrical bending are presented using the state-space-based differential quadrature method (SSDQM). Partial differential state equation is derived from the basic equations of elasticity based on the state space concept. Then, the differential quadrature (DQ) technique is introduced to discretize the longitu- dinal domain of the plate so that a series of ordinary differential state equations are obtained at the discrete points. Meanwhile, the edge constrained conditions are handled directly using the stress and displacement components without the Saint-Venant principle. The thickness domain is solved analytically based on the state space formalism along with the continuity conditions at interfaces. The present method is validated by comparing the results to the exact solutions of Pagano’s problem. Numerical results for fully clamped thick laminates are presented, and the influences of ply angle on stress distributions are discussed.     

民族语言授课远程高等教育发展的比较分析

总结了国内少数民族语言授课远程高等教育的发展过程,并比较分析了同一时期维吾尔语授课和蒙古语授课远程高等教育发展状况,由此提出了创办和发展蒙古语授课现代远程高等教育的启示。     

Strategien zur webbasierten Multilingualen Fragebeantwortung

Zusammenfassung  Wir stellen eine Reihe von innovativen Methoden zur webbasierten multilingualen Fragebeantwortung in offenen Dom?nen vor. Insbesondere werden neuartige Strategien zur Bestimmung optimaler Antwortkontexte und zur Extraktion von exakten Antworten auf Basis von sprachunabh?ngigen, datengetriebenen maschinellen Lernverfahren beschrieben. Es werden zwei alternative Methoden für die crosslinguale Frageanalyse skizziert mit deren Hilfe für eine Anfrage in einer natürlichen Sprache Antworten in Dokumenten einer anderen natürlichen Sprache bestimmt werden k?nnen. Alle Methoden sind detailliert evaluiert und weisen eine vielversprechende Performanz auf. CR subject classification  I.2.6 ; I.2.7 ; J.1 ; K.3.2 ; D.3.3 ; D.2.2     

Prior knowledge in mathematics and study success in engineering: informational value of learner data collected from a web-based pre-course

The article describes the development and evaluation of a web-based pre-course in mathematics, delivered to four cohorts of engineering students at a German university. Based on demographic, personal, and learning-related data relationships between students’ preconditions, their learning gains in the pre-course, and study success in the degree programme were analysed. The results support the existing literature in that domain-related prior knowledge and secondary school achievement play a dominant role regarding study success in engineering. The analyses also showed that the influence of cognitive predictors could only be compensated for by a strong learner engagement. At-risk students with high pre-course learning gains showed significantly better first-year performance. The number of self-tests a student attempted was positively related to pre-course learning gains and even to first-year performance, suggesting that this variable is a good indicator of student engagement.     

Vapor-liquid equilibrium simulation of binary and ternary mixtures of CH4, C2H4 and iso-C4H10

The vapor-liquid equilibrium（VLE） properties for the binary and ternary mixtures of CH4,C2H4 and isoC4H10 are of great importance in the recovery of ethylene from mixture containing CH4 and C2H4 with iso-C4H10 as solvent.Hence,Gibbs ensemble Monte Carlo（GEMC） simulations were used to estimate vapor-liquid equilibrium for the binary and ternary mixtures of CH4,C2H4 and iso-C4H10 with the united atom potential NERD model.The selected simulation conditions are based on the experiment in the literature.The results of this work were shown to be in satisfactory agreement with available experimental data and predictions of Peng-Robinson equation of state.The structure of simulated liquid phase is also characterized by radial distribution function（RDF）,which contributes to further understanding of the VLE curve of these systems.RDF is not sensitive to the pressure and temperature range.With the increase of pressure or the decrease of temperature,the molecules tend to gather together.     

发挥学会优势 服务科技创新

<正>创新是实现经济迅速发展的原动力,科协是国家推动科技事业发展的重要力量,在国家创新体系中具有独特的组织网络资源优势、特殊的主体地位和不可或缺的作用。近年来,在上级科协领导的指导和支持下,我会充分发挥学会优势,将推动科技创新摆在各项工作的首位,积极调整社会定位,充分发挥学会功能,为推进创新型城市建设做出了积极贡献。     

Stichwort: Professionelle Kompetenz von Lehrkräften

Ohne Zusammenfassung      

The Colorado Learning Attitudes about Science Survey (CLASS) for use in Biology

This paper describes a newly adapted instrument for measuring novice-to-expert-like perceptions about biology: the Colorado Learning Attitudes about Science Survey for Biology (CLASS-Bio). Consisting of 31 Likert-scale statements, CLASS-Bio probes a range of perceptions that vary between experts and novices, including enjoyment of the discipline, propensity to make connections to the real world, recognition of conceptual connections underlying knowledge, and problem-solving strategies. CLASS-Bio has been tested for response validity with both undergraduate students and experts (biology PhDs), allowing student responses to be directly compared with a consensus expert response. Use of CLASS-Bio to date suggests that introductory biology courses have the same challenges as introductory physics and chemistry courses: namely, students shift toward more novice-like perceptions following instruction. However, students in upper-division biology courses do not show the same novice-like shifts. CLASS-Bio can also be paired with other assessments to: 1) examine how student perceptions impact learning and conceptual understanding of biology, and 2) assess and evaluate how pedagogical techniques help students develop both expertise in problem solving and an expert-like appreciation of the nature of biology.     

Übereinstimmung,Variabilität und Reliabilität von Schülerurteilen zur Unterrichtsqualität auf Schulebene

Using student ratings to assess instructional quality of schools should fulfill three requirements: (1) an appropriate level of inter-rater agreement within schools, (2) systematic variance of student ratings between schools, (3) an adequate reliability level of aggregated student ratings. Using international PISA-data (2000–2012; 81 countries, over 55,300 schools, over 1.3 million 15-year olds) this study investigated how these requirements were met regarding indicators of instructional quality (classroom management, cognitive activation, individual learning support). We computed the interrater agreement index r_WG(J), as well as the intraclass correlations ICC(1) and ICC(2). Our results showed that (1) student ratings demonstrated a moderate or strong level of agreement for most indicators of instructional quality and (2) instructional quality assessed by students varied systematically between schools. Yet, (3) reliability of aggregated student ratings was not sufficient in many countries. We discuss these results regarding conventions to evaluate agreement, variability, and reliability of student ratings at the school level.