A follow-up study of students using portable computers at a secondary school

This paper reports on the findings of a 1999 study that set out to investigate the current perceptions of students and teachers towards the use of portable computers at a secondary school. The aim was to compare these with the findings of a 1995 study carried out by the researcher at the same school. Data were collected from 102 Year Twelve students (17 year old), 104 Year Eight students (13 year old) and 40 teachers. The results indicated that for the Year Twelve students the computers had been of limited value while the Year Eight students appeared to be divided with about a quarter indicating negative attitudes. For the younger students the computers appeared to be used more often and for a greater range of tasks. Many teachers indicated concerns about the management of computers in the classroom and linking computer use to learning outcomes. These perceptions underline the need for targeted professional development, systematic support for the development of student computer-related skills, and changes in the curriculum towards more learner-centred approaches.     

巧用简单装置演示“电场中的电势能”

"电势能和电势"的概念抽象难懂,不易理解。教学过程中通常出现"教师讲得明白,学生听得糊涂"的现象。如何能让学生直观地"看到"电势能一直是广大教师追求的目标。笔者利用实验室常见的仪器感应起电机和平行金属板,进行简单设计,将"抽象神秘"的电势能变得"直观可见"。     

Fatigue crack growth rate test using a frequency sweep method

Fatigue crack propagation characteristics of a diesel engine crankshaft are studied by measuring the fatigue crack growth rate using a frequency sweep method on a resonant fatigue test rig. Based on the phenomenon that the system frequency will change when the crack becomes large, this method can be directly applied to a complex component or structure. Finite element analyses （FEAs） are performed to calibrate the relation between the frequency change and the crack size, and to obtain the natural frequency of the test rig and the stress intensity factor （SIF） of growing cracks. The crack growth rate i.e. da/dN-AK of each crack size is obtained by combining the testing-time monitored data and FEA results. The results show that the crack growth rate of engine crankshaft, which is a component with complex geometry and special surface treatment, is quite different from that of a pure material. There is an apparent turning point in the Paris＇s crack partition. The cause of the fatigue crack growth is also discussed.     

The potential of immersive virtual reality to enhance learning: A meta-analysis

Research on the impact of immersive virtual reality (I-VR) technology on learning has become necessary with the decreasing cost of virtual reality technologies and the development of high-quality head-mounted displays. This meta-analysis investigates the overall effect size by combining the results of primary experimental studies that reveal the effect of I-VR on learning outcomes. Besides, effect sizes were calculated based on measuring moment, types of measurement, education level, the field of education, control group educational resources, and immersion type subgroups. One hundred five independent results were calculated from 48 primary studies published between 2016 and September 2020, including 39 randomized controlled trials and nine quasi-experimental studies. The sample size of primary studies includes 3179 students, 847 from K12, and 2332 from higher education. Random effects model was used in the calculation of effect size. As a result of the meta-analysis, it was determined that the overall effect size on the learning outcomes of I-VR was small (g = 0.38). Additionally, according to the subgroup analysis results, it was revealed that I-VR significantly differentiated effect size based on educational level, the field of education, and computer-based/traditional sources. There was no significant difference in terms of the other subgroups.     

Evaluating conditioning of related and unrelated stimuli using a compound test

Three experiments used a compound test procedure to evaluate whether superior conditioning results from the pairing of stimuli that are related to each other. In each case, a stimulus compound was tested after its component conditioned stimuli (CSs) had been conditioned by the same unconditioned stimuli (USs) arranged such that either related or unrelated CSs and USs were paired. Experiment 1 explored auditory and gustatory stimuli conditioned by LiCl or shock, using rats. Experiments 2 and 3 used second-order conditioning in pigeons to pair stimuli that were similar by virtue either of qualitative features or of shared physical location. In each case, the compound test provided clear evidence that pairing related stimuli produces superior associative learning.     

Assessment of early handwriting skill in kindergarten children using a Chinese name writing test

Reading and Writing - This study developed and validated a Chinese name writing scale (CNWS) for evaluating early handwriting skills of kindergarten children. We then used the validated CNWS to...     

三维地质力学模型试验中光纤传感器的应用研究

近年来，在地下结构三维地质力学模型试验的研究中。多项新技术得到应用和开发，其中也包括采用光纤传感器量测模型材料中的应变和变形，这使模型试验上了一个新台阶。采用光纤传感器量测。对于地质力学模型试验来说还是一项新技术。该文结合在一个大比尺的地质力学模型试验中采用光纤传感器的经验，对它的实际应用及埋设方法做了进一步的探讨和设想。     

Gender differences in academic self-efficacy: a meta-analysis

A meta-analysis of 187 studies containing 247 independent studies (N?=?68,429) on gender differences in academic self-efficacy identified an overall effect size of 0.08, with a small difference favoring males. Moderator analysis demonstrated that content domain was a significant moderator in explaining effect size variation. Females displayed higher language arts self-efficacy than males. Meanwhile, males exhibited higher mathematics, computer, and social sciences self-efficacy than females. Gender differences in academic self-efficacy also varied with age. The largest effect size occurred for respondents aged over 23 years old. For mathematics self-efficacy, the significant gender differences emerged in late adolescence. Future research should longitudinally examine gender differences in academic self-efficacy to determine the prevalence of gender differences during different life stages.     

A model for increasing decision making potential through standardized test scores

The development of a model for more effective usage of group administered standardized tests is developed. The primary assumption is that summary data from these instruments are not used in curricular decisions for groups larger than the classroom unit, and a method is illustrated which uses item groupings from subtests allowing a more effective use of the data for program and curricular decisions. Several cautions are presented with respect to data usage in the recommended fashion, i. e., item data usually have low reliability coefficients, and criterion levels which identify problems in the curriculum are difficult to establish.     

设计小体积密闭试验舱评价甲醛降解效率

本文设计一个半开放式综合性实验项目,运用自制的小体积密闭试验舱来检测纳米TiO_2材料对甲醛光催化降解性能。实验设计中,对舱体进行综合评价后,选取水热法制备的铁掺杂纳米TiO_2和氮掺杂纳米TiO_2作催化剂降解甲醛,比较了其在可见光下对甲醛的降解效果,最后通过动力学研究可知甲醛在纳米TiO_2表面氧化反应符合一级动力学方程。该综合性实验项目设计覆盖了多学科交叉的综合训练,有助于把学生培养成"具有创新精神和实践能力的高级专门人才"。     

A cross-cultural comparison of numeracy skills using a written and an interactive arithmetic test

This study applied two arithmetic tests, one written and one one computer-based interactive, to samples of primary school children from two populations, one suburban non-Aboriginal and one rural Aboriginal. The results from the written test were significantly (p?&;lt;?0.001) better for the non-Aboriginal children than for the Aboriginal children. This was not the case with the results from the computer-based interactive test. The study used Rasch-based methodology to reduce the results from the two tests to a common scale, to ascertain whether the Aboriginal children performed better (in relation to the non-Aboriginal children) in the computer-based than in the written test. The study found that this was the case, and concluded that the results from the computer-based test exhibited less cultural bias against the Aboriginal children than the written test.     

利用一种新的势能函数精确计算双原子的光谱参数

A novel scheme for potential energy functions of diatomic molecules is derived using a function with phase factors. Six kinds of potential curves of common shapes are obtained by adjusting the phase factors. Spectroscopic parameters of the ground states for ten kinds of molecules are calculated using the potential energy functions. The results agree well with experimental data.     

筋带-砂-粘土层状体系直剪试验研究

为了研究粘土与加筋材料接触面之间的力学特性,及砂对粘土与筋带接触面力学特性的改善情况,采用直剪试验方法对粘土与聚丙烯土工带polypropylene在粘土不同含水量条件下进行了不同法向荷载作用的直剪试验,讨论了法向应力、含水量对高液限粘土与筋带之间剪切特性的影响;设计了筋带砂粘土层状布置体系的加筋土结构模型,并根据设计的模型进行直剪试验.试验结果表明:粘土与筋带接触面之间的剪切强度随着法向应力的增加呈非线性增长;接触面的摩擦系数随着含水量的增加而减小,接触面的粘聚力随含水量的增加先增大后减小,粘土与接触面之间存在一个最佳的含水量,这个值要比粘土压实的最佳含水量低2%左右;筋带砂粘土层状布置体系表明砂对粘土与筋带的剪切特性起到明显的改善作用.     

Effects of problem-based learning: a meta-analysis

This meta-analysis has two aims: (a) to address the main effects of problem based learning on two categories of outcomes: knowledge and skills; and (b) to address potential moderators of the effect of problem based learning. We selected 43 articles that met the criteria for inclusion: empirical studies on problem based learning in tertiary education conducted in real-life classrooms. The review reveals that there is a robust positive effect from PBL on the skills of students. This is shown by the vote count, as well as by the combined effect size. Also no single study reported negative effects. A tendency to negative results is discerned when considering the effect of PBL on the knowledge of students. The combined effect size is significantly negative. However, this result is strongly influenced by two studies and the vote count does not reach a significant level. It is concluded that the combined effect size for the effect on knowledge is non-robust. As possible moderators of PBL effects, methodological factors, expertise-level of students, retention period and type of assessment method were investigated. This moderator analysis shows that both for knowledge- and skills-related outcomes the expertise-level of the student is associated with the variation in effect sizes. Nevertheless, the results for skills give a consistent positive picture. For knowledge-related outcomes the results suggest that the differences encountered in the first and the second year disappear later on. A last remarkable finding related to the retention period is that students in PBL gained slightly less knowledge, but remember more of the acquired knowledge.     

电位法测定水中硫酸盐的研究

提出了用离子选择电极电位法测定硫酸盐的新方法.在最佳条件下,电极电位与硫酸盐浓度在1×10-5～1×10-2mol/L之间有良好线性关系,检测下限为6.3×10-6/mol/L.该方法简便准确,已用于水中硫酸盐测定,结果满意.     

3D Magnetic Field Computation of a Permanent MagnetDisc-Type Generator Using Scalar Potential Method

The three-dimensional magnetic field of a permanent magnet (PM) disc-type generator is analyzed by the scalar potential method. In the analysis the permanent magnets are taken as magnetic charges. Hexahedron element meshes are automatically generated by a pre-processing program developed by the authors. The flux density is computed by a 3D scalar potential method program. Based on the finite element analysis the induced emf, current, armature reaction effects and electromagnetic torque of the disc machine are all calculated.     

利用图解法解碱基计算题

本文介绍了DNA分子中碱基比例及碱基数计算的图解方法。并用例题加以说明。     

应用Excel进行生物学试卷分析

试卷统计分析是生物学教学的一个重要环节，目前教师们普遍难以对试卷进行快速准确的统计分析，本文提出应用Excel进行试卷分析．其统计分析方法方便、快速、准确，是教学中评价试卷的较好方法之一。