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The antecedents of in-service teacher burnout:A study of their occupational health and perception
Angus C. H. Kuok,Stacy M. I. Lam 한국교육개발원 2018 KEDI Journal of Educational Policy Vol.15 No.2
As Macau is one of the cities with high students’ grade retention rate, the local teachers, therefore, have a considerably heavy workload to prepare the students to achieve the requirements of a particular academic setting. This study examined 173 full-time in-service secondary school teachers at Macau via questionnaire. The result shows in-service teachers feel emotional exhaustion in teaching students. However, teachers perceive their competence in teaching and would not depersonalize the students as an object. Moreover, significant variations are found among the three factors of burnout for teachers. That is, teachers experience higher emotional exhaustion than reduced personal accomplishment and depersonalisation. By reviewing previous studies about teachers’ burnout as compared to the present findings, an upward trend of teachers’ emotional exhaustion is suggested. The increase of emotional exhausting could be related to the launch of new policies in terms of enhancing the professionalism of teachers. Needs for achievement, which is negatively correlated to burnout, is found to be a powerful predictor. Organisational socialisation in terms of training, understanding, co-worker support, and future prospects are discovered to have negative correlations to burnout. Particularly, understanding and future prospect are found to be the negative predictors of reduced personal accomplishment and emotional exhaustion, respectively. The results and implications are interpreted for teachers’ professional development and school administration.
The Local Web Buckling Strength of Stiffened Coped Steel I-Beams
Michael C. H. Yam,Angus C. C. Lam,Feng Wei,K F Chung 한국강구조학회 2007 International Journal of Steel Structures Vol.7 No.2
In steel construction the flange of a steel I-beam is usualy coped to allow clearance at the connection. The presence of acope in a beam wil reduce the strength of the beam in the coped region. Local web buckling at the coped region may occurwhen the cope length is long and/or the cope depth is large, provided that lateral-torsional buckling of the beam is prevented.coped I-beams although no experimental evidence was provided to support the recomendation. In order to verify suchrecomendation, an experimental and numerical investigation of coped I-beams with stiffeners at the coped region wasconducted and reported in this paper. The study showed that current recommendations did not consider the web distortionproperly, i.e. local web buckling could not be prevented efficiently if only horizontal stiffeners were provided at the copedregion. Both the test and the numerical results showed that the horizontal stiffeners at the cope displaced lateraly due to grossweb distortion. Based on the results of the parametric study of coped beams with diferent configurations of horizontal andvertical stiffeners, it was found that for cope depth to beam depth ratio (dc/D)≥0.3, both horizontal and vertical stiffeners arerequired in order to prevent local web buckling at the cope region. A preliminary recomendation for the design of copedbeams with both horizontal and vertical stiffeners was proposed according to the key findings of the investigation.
Degradation of thin carbon-backed lithium fluoride targets bombarded by 68 MeV 17O beams
김용현,Davids B.,Williams M.,Hudson K.H.,Upadhyayula S.,Alcorta M.,Machule P.,Esker N.E.,Griffin C.J.,Williams J.,Yates D.,Lennarz A.,Angus C.,Hackman G.,김동건,J. Son,Park J.,Pak K.,김용균 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.3
To analyze the cause of the destruction of thin, carbon-backed lithium fluoride targets during a measurement of the fusion of 7Li and 17O, we estimate theoretically the lifetimes of carbon and LiF films due to sputtering, thermal evaporation, and lattice damage and compare them with the lifetime observed in the experiment. Sputtering yields and thermal evaporation rates in carbon and LiF films are too low to play significant roles in the destruction of the targets.We estimate the lifetime of the target due to lattice damage of the carbon backing and the LiF film using a previously reported model. In the experiment, elastically scattered target and beam ions were detected by surface silicon barrier (SSB) detectors so that the product of the beam flux and the target density could be monitored during the experiment. The areas of the targets exposed to different beam intensities and fluences were degraded and then perforated, forming holes with a diameter around the beam spot size. Overall, the target thickness tends to decrease linearly as a function of the beam fluence. However, the thickness also exhibits an increasing interval after SSB counts per beam ion decreases linearly, extending the target lifetime. The lifetime of thin LiF film as determined by lattice damage is calculated for the first time using a lattice damage model, and the calculated lifetime agrees well with the observed target lifetime during the experiment. In experiments using a thin LiF target to induce nuclear reactions, this study suggests methods to predict the lifetime of the LiF film and arrange the experimental plan for maximum efficiency