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131.
Nilmara Braga Mozzer 《International Journal of Science Education》2013,35(3):429-458
Analogies are parts of human thought. From them, we can acquire new knowledge or change that which already exists in our cognitive structure. In this sense, understanding the analogical reasoning process becomes an essential condition to understand how we learn. Despite the importance of such an understanding, there is no general agreement in cognitive science literature about this issue. In this study, we investigated students' analogical reasoning as a creative process where an environment was set up to foster the students' generating and explaining their own analogies. Data were gathered from pre- and post-teaching interviews, in which the 13–14-year-old students were asked to make comparisons that could explain how atoms are bound. Such data supported the discussion about how students reasoned analogically. Our results made it evident that the task aims and the students' salient knowledge exerted a great influence on the drawing of analogies. 相似文献
132.
发动机燃烧模型的发展经历了零维模型,准维模型,多雏模型三个阶段。双燃料发动机是气体燃料使用的主要方式,针对国内外双燃料发动机燃烧模型的研究进展和现状,介绍了气体-柴油双燃料发动机的三维燃烧模型应包含的子模型和计算方法。 相似文献
133.
The CAS Dalian Institute of Chemical Physics(DICP)and BP Group will join efforts to set up an Energy Innovation Laboratory(BP- DICP EIL)at DICP.The agreement for the new initiative was signed by DICP Director ZHANG Tao and BP Group Vice President Tony Meggs on 5 December,2007 in Dalian. According to the agreement, BP will donate $3 million to the new lab,which will be part of the forthcoming National Laboratory for Clean Energy Sources.In addition,the company promises to annually contribute no less than ... 相似文献
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136.
通过对台州师专生化专业学生的化学实验状况调查,了解中学化学和高师无机化学实验现状,对高师无机化学实验如何加强与中学化学实验的联系,提高学生实验素质,提出一些改进对策。 相似文献
137.
THE POLYMERIZATION OF METHYL METHACRYLATE WITH A NEW TIN-BRIDGED YTTROCENE/Al(i-Bu)_3 总被引:1,自引:0,他引:1
INTRODUCTIONSincethepolymerizationofmethylmethacrylate(MMA)withrareearthcatalystswasrealizedforthefirsttimein1991,aseriesofnewrareearthcatalystsystemssuchasNd(P204)3/Al(iBu)3,Nd(P204)3/Al(iBu)3/CCl4,Nd(Oct)3/Al(iBu)3,Ln(acac)3/BuMgCl,Y(acac)3/Al(iBu)3/BuLi,Nd(naph)3/BuLi,andNd(O… 相似文献
138.
A novel iron-ytterbium dinuclear catalyst, FcB(MeCp) Yb (MeCp) Cl (Fc: ferrocenyl, B: diethylene ether), was synthesized for
the polymerization of methyl methacrylate (MMA). Synergistic effects between the ferrocenyl group and the lanthanocene part
were investigated regarding their catalytic behaviors. UV, IR, GPC and NMR were used to characterize the structures of the
catalyst and polymer. Kinetic study showed that polymerization is first order in monomer concentration and fractional order
(0.78) in the catalyst. The bimetallic complex is a good catalyst for the polymerization of MMA, giving high molecular weight
PMMA with 78% syndiotactivity.
Project (29774021) supported by NSFC and Laboratory of Rare-Earth Chemistry and Physics, Changchun Institute of Applied Chemistry,
Chinese Academy of Sciences 相似文献
139.
David Zahradnik Daniel Jandacka Gabriela Beinhauerova Joseph Hamill 《Journal of sports sciences》2020,38(20):2367-2373
ABSTRACT The lateral tilt of the arms accompanied by trunk lateral tilt is a typical blocking manoeuvre in volleyball. However, during this unanticipated blocking movement, an associated risk of ACL injury may result. The aim of the present study was to compare associative ACL risk factors at the initial contact and the first and second peak of VGRF during an unanticipated blocking movement with different arm positions. Synchronized kinematic and kinetic data were collected for each trial of each condition. Student paired t-tests and effect size were used to determine differences between two conditions (S – with arms straight up from the body) and (T – with the arms and trunk laterally tilted). The results showed that the T condition significantly decreases knee flexion, increases VGRF at the foot contact, first peak force and increases the valgus moment at the first peak force. The values of the associated risk factors for a non-contact ACL injury appear to be related to the tilted arm position accompanied by trunk tilt towards to right lower limb during landing. The players should be taught to land with greater knee flexion and, if possible, a double-leg landing to decrease right lower limb loading during the blocking manoeuvre. 相似文献
140.
Thomas Dos’Santos Paul Comfort Paul A. Jones 《Sports biomechanics / International Society of Biomechanics in Sports》2020,19(4):483-492
ABSTRACT The aims of this study were twofold: firstly, to compare lower limb kinematic and kinetic variables during a sprint and 90° cutting task between two averaging methods of obtaining discrete data (peak of average profile vs. average of individual trial peaks); secondly, to determine the effect of averaging methods on participant ranking of each variable within a group. Twenty-two participants, from multiple sports, performed a 90° cut, whereby lower limb kinematics and kinetics were assessed via 3D motion and ground reaction force (GRF) analysis. Six of the eight dependent variables (vertical and horizontal GRF; hip flexor, knee flexor, and knee abduction moments, and knee abduction angle) were significantly greater (p ≤ 0.001, g = 0.10–0.37, 2.74–10.40%) when expressed as an average of trial peaks compared to peak of average profiles. Trivial (g ≤ 0.04) and minimal differences (≤ 0.94%) were observed in peak hip and knee flexion angle between averaging methods. Very strong correlations (ρ ≥ 0.901, p < 0.001) were observed for rankings of participants between averaging methods for all variables. Practitioners and researchers should obtain discrete data based on the average of trial peaks because it is not influenced by misalignments and variations in trial peak locations, in contrast to the peak from average profile. 相似文献