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1.
借助数轴透析“一种金属与溶液中多种盐反应”和“多种金属与溶液中一种盐反应”中溶质与滤渣的组成,直观地将反应进程和结果展现其中,建立思维模型,化难为易,有利于学生掌握与应用。 相似文献
2.
Farzad Radmehr Michael Drake 《International Journal of Mathematical Education in Science & Technology》2017,48(7):1043-1071
Several studies have explored students’ understanding of the relationships between definite integrals and areas under curve(s). So far, however, there has been less attention to students’ understanding of the Fundamental Theorem of Calculus (FTC). In addition, students’ metacognitive experiences and skills whilst solving FTC questions have not previously been explored. This paper explored students’ mathematical performance, metacognitive experiences and metacognitive skills in relation to FTC questions by interviewing nine university and eight Year 13 students. The findings show that several students had difficulty solving questions related to the FTC and that students’ metacognitive experiences and skills could be further developed. 相似文献
3.
This paper investigated the validation of a multi-criteria method for identifying potential roads, and demonstrated the capability of analyzing GPS vehicle tracking data for identifying vehicle movement patterns and potential roads. The multi-criteria method was evaluated by comparing the predictions to the site visit results on 34 selected road segments meeting different criteria levels. Results show that locations meeting higher criteria levels have higher possibilities to be roads: an approximately 91% possibility of road existence for the locations meeting all five criteria; 55% for the locations meeting four criteria; and 14% for those meeting criteria level two or three. This approach provides an opportunity for land managers to update existing GIS roads map, or identify newly formed roads that may need either rehabilitation or inclusion into the roads maintenance program. 相似文献
4.
Overwinter changes to near-surface bulk density, penetration resistance and infiltration rates in compacted soil 总被引:2,自引:0,他引:2
Previous studies at Yakima Training Center (YTC), in Washington State, suggest freeze-thaw (FT) cycles can ameliorate soil compacted by tracked military vehicles [J. Terramechanics 38 (2001) 133]. However, we know little about the short-term effects of soil freezing over a single winter. We measured bulk density (BD), soil penetration resistance (SPR), and steady-state runoff rates in soil newly tracked by an Abrams tank and in uncompacted soil, before and after a single winter at YTC. We similarly measured BD, SPR and saturated hydraulic conductivity (kfs) in simulated tank tracks at another site near Lind Washington. Average BD was significantly greater in tank ruts at YTC and in simulated tracks at the Lind site than in uncompacted soil soon after tracking and did not change significantly during the winter of 1997–1998. Measurements of SPR were strongly influenced by soil moisture. When soil was moist or tracks were newly formed, SPR was significantly higher in tank ruts than in uncompacted soil from the surface to a depth of about 10–15 cm. The greatest average SPR in compacted soil was observed between 4 and 6 cm depth. We observed less difference in SPR between tank ruts and uncompacted soil near-surface at YTC as the time after trafficking increased. We observed highest SPR ratios (compacted rut:undisturbed) in fresh tracks near the surface, with lower ratios associated with increasing track age or soil depth, indicating that some recovery had occurred at YTC near-surface. However, we did not observe a similar over-winter change in SPR profiles at the Lind site. Rainfall simulator data from YTC showed higher steady-state runoff rates in tank ruts than over uncompacted soil both before and after winter. However, more time was required to reach steady-state flow in tank ruts and the proportion of runoff was slightly lower in May 1998 than in August 1997. At the Lind site, kfs was lower in newly compacted soil than in one-year old compacted soil or uncompacted soil. Our data suggest that indices of water infiltration such as steady-state runoff rates or kfs, are more sensitive indicators of soil recovery after compaction than are BD or SPR. 相似文献
5.
Wael Zaki 《Journal of the mechanics and physics of solids》2007,55(11):2427-2454
The model in the first part of this paper is extended to account for SMA behavior under cyclic loading. To this end, three new state variables are introduced: internal stress B, residual strain ?r and cumulated martensite volume fraction ze. Several parameters of the extended model depend on ze, making them evolve with cyclic phase change. Cyclic SMA effects including training and two-way shape memory are accounted for and several numerical simulations are provided and validated in the case of cyclic superelasticity. 相似文献
6.
生态环境脆弱区工程地质研究是工程地质学科必须面对的一个重要领域。作者指出,工程地质学应当夯实学科基础,吸取相关学科理论,重塑工程地质理论与实践,出精品工程,重视人才培养。 相似文献
7.
Thierry Dana-Picard Aaron Naiman 《International Journal of Mathematical Education in Science & Technology》2013,44(6):865-877
Geometric constructions have previously been shown that can be interpreted as rays of light trapped either in polygons or in conics, by successive reflections. The same question, trapping light in closed Fermat curves, is addressed here. Numerical methods are used to study the behaviour of the reflection points of a triangle when the degree of the curve varies, including a generalization to non integer powers. 相似文献
8.
9.
基于证据推理的教学是回应化学史、指向未来、面向现在的教学。以“氧气的性质和用途”的教学实践为例,说明了基于证据推理的教学的重要性:可以帮助学生夯实化学基础知识,掌握必备基本技能;形成基本化学观念,初步认识物质世界;掌握科学思维方式,科学分析解决问题,从而帮助学生开启化学之门。 相似文献
10.
Jackie Reid Janelle Wilkes 《International Journal of Mathematical Education in Science & Technology》2016,47(6):837-852
Mapping quantitative skills across the science, technology, engineering and mathematics (STEM) curricula will help educators identify gaps and duplication in the teaching, practice and assessment of the necessary skills. This paper describes the development and implementation of quantitative skills mapping tools for courses in STEM at a regional university that offers both on-campus and distance modes of study. Key elements of the mapping project included the identification of key graduate quantitative skills, the development of curriculum mapping tools to record in which unit(s) and at what level of attainment each quantitative skill is taught, practised and assessed, and identification of differences in the way quantitative skills are developed for on-campus and distance students. Particular attention is given to the differences that are associated with intensive schools, which consist of concentrated periods of face-to-face learning over a three-four day period, and are available to distance education students enrolled in STEM units. The detailed quantitative skills mapping process has had an impact on the review of first-year mathematics units, resulted in crucial changes to the curriculum in a number of courses, and contributed to a more integrated approach, and a collective responsibility, to the development of students' quantitative skills for both face-to-face and online modes of learning. 相似文献