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1.
Marie‐Geneviève Séré 《International Journal of Science Education》2013,35(3):299-309
Summaries English When children interpret experiments concerning the physical properties of gases, they generally use frameworks from the field of mechanics. In reality, these experiments give them the opportunity of expressing relationships between movement, equilibrium and mechanical dimensions, such as forces. In their experimental interpretations, children aged 11 to 13 years emphasize in most cases those stages of an experiment which involve movement: movement as a cause of pressure change of a gas, and movement as the effect of this pressure change. This leads them to express frameworks which have been similarly observed by Piaget and other authors. For example, movement of air in one direction is thought to cause or to be caused by a specific force in one direction; similarly, the state of equilibrium and thus the immobility at the end of the experiment, are characterized by an absence of forces. The interpretations of several experiments relating to air pressure are analysed using the commentaries of children aged 11 to 13 in class and interviews carried out with children of the same age. 相似文献
2.
Tilbe Göksun Nathan R. George Kathy Hirsh‐Pasek Roberta M. Golinkoff 《Child development》2013,84(4):1285-1295
How do children evaluate complex causal events? This study investigates preschoolers' representation of force dynamics in causal scenes, asking whether (a) children understand how single and dual forces impact an object's movement and (b) this understanding varies across cause types (Cause, Enable, Prevent). Three‐and‐a half‐ to 5.5‐year‐olds (n = 60) played a board game in which they were asked to predict the endpoint of a ball being acted upon by one or two forces. Children mostly understood the interactions of forces underlying each type of cause; only 5.5‐year‐olds could integrate two contradictory forces. Children perceive force interactions underlying causal events, but some concepts might not be fully understood until later in childhood. This study provides a new way of thinking about causal relations. 相似文献
3.
自然生产力：后现代生产力的核心范畴——生态文明建设的哲学思考 总被引：1，自引：0，他引：1
现代生产力是以工业文明为标志的社会生产力的一统天下,后现代生产力是以自然生产力的优先发展、充分发展、重点发展为核心,以自然生产力与社会生产力的协调发展、全面发展、永续发展为目标的生产力,是一种真正意义上的大生产力。生态文明作为破解生态危机的时代选择,是对工业文明的扬弃和革命,与后现代生产力具有本质上的一致性。 相似文献
4.
柴绪亮 《湖南第一师范学报》2002,2(4):5-8
生产力是一切社会发展的最终决定力量，解放生产力与发展生产力是社会主义的本质内容和根本任务。在发展生产力上，毛泽东和邓小平的目标与愿望相同，并且都把其作为“共同富裕”的前提和基础，都重视科学技术的作用；在解放生产力上，毛泽东侧重于生产关系与上层建筑的调整，侧重于从革命的角度谈“解放生产力”；邓小平则提出“要把解放生产力讲全”，“改革也是一场革命”，“改革也是解放生产力”，“科学技术是第一生产力”等观点，从而继承与发展了毛泽东“生产力思想”。 相似文献
5.
周彩屏 《金华职业技术学院学报》2005,5(1):66-69,97
城市化是我国新世纪发展进程中要解决的重要问题，是我国全面建设小康社会和推进现代化的重要动力。在城市化过程中，探索其动力特征，寻求其发展的方向，是我国各省城市化领域的重要课题。本文试图以浙江为例进行实证研究，认为区域块状经济作用、混合经济体制的驱动、大中城市的规模化扩张、外向型经济的带动等成为浙江城市化加速发展的动力，并对浙江未来城市化发展方向进行探索。 相似文献
6.
试论邓小平关于“科学技术是第一生产力”的光辉思想 总被引：3，自引：0，他引：3
陈火弟 《江西教育学院学报》2001,22(2):52-54
“科学技术是第一生产力”思想深刻，内涵丰富，从质的规定上，科学技术被定性为生产力；从序的规定上，科学技术被定为现代生产力的第一大要素；从地位和作用上，科学技术被定位为推动生产力发展的决定力量；从时代划分上，“科学技术是第一生产力”被定时为知识经济时代；从数学模型分析上，现代生产力等于科学技术与其它要素总和和乘积。 相似文献
7.
Objective:To discuss possible relationships between class III malocclusion and perioral forces by measuring the pressure from the lips and the tongue of children with class III malocclusion. Methods:Thirty-one children with class III malocclusion were investigated and their perioral forces were measured at rest and during swallowing under natural head position by a custom-made miniperioral force computer measuring system. Results:The resting pressures exerted on the labial side and palatine side of the upper left incisor, as well as the labial side and lingual side of the lower left incisor, were 0 g/cm2, 0 g/cm2, 0.57 g/cm2 and 0.23 g/cm2, respectively. Correspondingly, the swallowing forces were 2.87 g/cm2, 5.97 g/cm2, 4.09 g/cm2 and 7.89 g/cm2, respectively. No statistical difference between muscular pressure and gender existed. During swallowing, the lingual forces were significantly higher than the labial forces (P<0.01), however, at rest there was no significantly different force between these two sides. Compared to the normal occlusion patients, children with class III malocclusion had lower perioral forces. The upper labial resting forces (P<0.01), the lower labial resting forces (P<0.05) and all the swallowing pressures from the lips and the tongue (P<0.01) showed statistical differences between the two different occlusion conditions. Meanwhile, no significant difference was found for the resting pressure from the tongue between class III malocclusion and normal occlusion. Conclusion:Patients with class III malocclusion have lower perioral forces and this muscle hypofunction may be secondary to the spatial relations of the jaws. The findings support the spatial matrix hypothesis. 相似文献
8.
Miriam Reiner 《Interactive Learning Environments》2013,21(1):31-55
This paper examines the role of tactile perception in conceptual construction of forces and fields. The learning environment includes a simulation of a force field. The force applied by the field on an object is transferred to the learner's hand through a tactile interface designed as a trackball. The learner experiences varying resistance from the trackball when moving an object on the screen. The forces are actually “felt”, exerted on the screen-object as if the learner's hand is immersed in the “field.” We hypothesize that a tactile interface acts as an agent aimed at recruiting the body non-propositional knowledge, for construction of formal physics knowledge on fields of forces. Twelve subjects were asked to explore the structure of several invisible fields through tactile interface, then to design a series of situations that generate current and that energetically trap a particle in a particular area. The results of the study show that s tudents with no background in physics constructed a graphical representation of a field force of a single and double center of forces similar to the formal physics representation, though they had no conceptual background (i.e., vectors, field lines). Based on the tactile information, they constructed a representation of force as a vector, of force lines, equal-force lines (potential lines for particular cases), potential well (“trap”) and motion of a charged particle in a field of forces. We show that computer tactile interface acts as a trigger for access to non-propositional knowledge employed in everyday bodily activity, but not in formal learning. The computer environment turns into a virtual environment, carrying the features of perception within “reality”, providing opportunities for conceptual construction. 相似文献
9.
Objective： To discuss possible relationships between class In malocclusion and perioral forces by measuring the pressure from the lips and the tongue of children with class nI malocclusion. Methods： Thirty-one children with class In malocclusion were investigated and their perioral forces were measured at rest and during swallowing under natural head position by a custom-made miniperioral force computer measuring system. Results： The resting pressures exerted on the labial side and palatine side of the upper lett incisor, as well as the labial side and lingual side of the lower lett incisor, were 0 g/cm^2, 0 g/cm^2, 0.57 g/cm^2 and 0.23 g/cm^2, respectively. Correspondingly, the swallowing forces were 2.87 g/cm^2, 5.97 g/cm^2, 4.09 g/cm^2 and 7.89 g/cm^2, respectively. No statistical difference between muscular pressure and gender existed. During swallowing, the lingual forces were significantly higher than the labial forces （P〈0.01）, however, at rest there was no significantly different force between these two sides. Compared to the normal occlusion patients, children with class Ⅲ malocclusion had lower pedoral forces. The upper labial resting forces （P〈0.01）, the lower labial resting forces （P〈0.05） and all the swallowing pressures from the lips and the tongue （P〈0.01） showed statistical differences between the two different occlusion conditions. Meanwhile, no significant difference was found for the resting pressure from the tongue between class Ⅲ malocclusion and normal occlusion. Conclusion： Patients with class Ⅲ malocclusion have lower perioral forces and this muscle hypofunction may be secondary to the spatial relations of the jaws. The findings support the spatial matrix hypothesis. 相似文献
10.
Nikos Metallinos 《Educational technology research and development : ETR & D》1979,27(3):205-214
This article examines the structure of television pictures as based on the theory of field forces and suggests a series of
hypotheses, experimental designs, and statistical treatments to be used in empirical investigations. Various theoretical concepts
of composition (field forces) — asymmetry of the screen, main direction, magnetism of the frame, attraction of mass, figure/ground
relationships, psychological closure, and vectors — are discussed. The author hopes to encourage future research on the structure
of TV pictures that will enhance our understanding of the effects of visual communication media on viewers. 相似文献
11.
In this paper, quantitative measures for the assessment of the hydraulic excavator digging efficiency are proposed and developed. The following factors are considered: (a) boundary digging forces allowed for by the stability of an excavator, (b) boundary digging forces enabled by the driving mechanisms of the excavator, (c) factors taking into consideration the digging position in the working range of an excavator, and (d) sign and direction of potential digging resistive force. A corrected digging force is defined and a mathematical model of kinematic chain and drive mechanisms of a five-member excavator configuration was developed comprising: an undercarriage, a rotational platform and an attachment with boom, stick, and bucket. On the basis of the mathematical model of the excavator, software was developed for computation and detailed analysis of the digging forces in the entire workspace of the excavator. By using the developed software, the analysis of boundary digging forces is conducted and the corrected digging force is determined for two models of hydraulic excavators of the same mass (around 17 000 kg) with identical kinematic chain parameters but with different parameters of manipulator driving mechanisms. The results of the analysis show that the proposed set of quantitative measures can be used for assessment of the digging efficiency of existing excavator models and to serve as an optimization criterion in the synthesis of manipulator driving mechanisms of new excavator models. 相似文献
12.
示波器为什么会显示出与被测信号相同的波形？很多书中采用“立几中的投影原理”阐述。本文把电子束看成点电荷,在两对偏转板（x,y）作用下,即受到xy两个方向电场作用。分析点电荷在电场中受到垂直方向（y）,水平方向（x）的力而产生合力。在合力方向运动,其运动轨迹与被测信号波形相同。 相似文献
13.
当代媒介艺术生产力初探 总被引：1，自引：0，他引：1
从古至今,媒介一直是艺术生产力中的重要因素。在信息社会向纵深发展的21世纪,构成当代艺术生产力形态之一的媒介艺术生产力已经应运而生。媒介艺术生产实践中的作为艺术生产基础性物质力量和原动力的生产力形态就是媒介艺术生产力。媒介艺术生产力以当代新科技、新媒介催生出来的新型施动性媒介为生产工具,以高科技载体媒介及其设施为其他生产资料,以当代媒介带来的拟态环境或信息环境为重要生产对象,以当代高新媒介技术为主要生产技术,以当代媒介建构的艺术创造力、表现力为艺术生产者的主要生产能力。开展媒介艺术生产力研究对丰富马克思主义艺术生产理论和艺术生产力理论,促进马克思主义艺术生产论的当代化具有重要意义。 相似文献
14.
针对难加工球墨铸铁材料进行高速铣削工艺参数优化研究,设计了四因素四水平正交实验,以获得铣削用量对加工过程力和表面粗糙度的影响关系,并利用多元回归分析建立铣削分力和粗糙度的经验模型。研究结果表明:每齿进给量对粗糙度值影响最为显著,铣削参数设置不同,产生的铣削分力不同,背吃刀量对铣削分力影响最大。针对最小铣削力与最小粗糙度的目标,分别得出最优的铣削用量参数。 相似文献
15.
The Educational Forces Inventory (EFI) is a technique for assessing the constellation of forces in the teacher’s social-psychological field. Thereby, important stress points for teachers are identified and their work in the classroom is facilitated. The EFI charts the relative influence of each of 13 forces that are important factors in the educational settting. Teachers are asked to characterize each force along two dimensions: the amount of influence it exerts upon the classroom process, and the degree to which this influence is positive or negative. Several hundred teachers and teaching assistants in Follow Through classrooms throughout the country participated in a field test of the instrument, with concurrent administration of the Purdue Teacher Opinionaire (PTO), an established measure of teacher morale. The high rate of return and correct completion on the EFI indicated that it is a practical technique. In addition, the data indicated validity for the instrument in three important respects: (1) the pattern-of-importance ratings correspond to independently assessed patterns of physical and social distance; (2) the positive/negative ratings for particular forces correlated substantially with corresponding subscores of the PTO; and (3) the pattern of responses reflected aspects of internal consistency. Some ways of utilizing EFI data are discussed: how to plot and interpret two-dimensional force fields, and how to use them in program implementation, especially to facilitate the work of the teacher in the classroom. 相似文献
16.
In this paper, the effects of second-order difference-frequency wave forces on the global motion of an offshore wind turbine system with a large displacement under the survival condition are studied. In this case, the hydrodynamic force is the main force because the blades are feathered to reduce the lifting force. The first-order hydrodynamic forces are calculated by WADAM, while the second-order wave forces are calculated by a customized MATLAB module. Then the hydrodynamic coefficients are transferred to the wind turbine analytical code FAST. Through the comparisons of dynamic responses between the first- and second-order numerical models, it is found that the second-order wave forces significantly influence the motion of floating wind turbine under the survival condition. Moreover, neglecting the second-order force significantly underestimates the tension forces in the mooring lines. 相似文献
17.
工程力学中杆件内力计算的简捷方法是指利用截面左右侧上的外力直接计算内力.根据杆件发生不同的基本变形,可以归纳为:杆件某一截面上的内力等于截面一侧所有外力在沿杆轴线方向或垂直杆轴线方向上投影的代数和,或所有外力对截面形心的力矩的代数和. 相似文献
18.
王红梅 《常熟理工学院学报》2008,22(9):30-34
改革开放是党在新的时代条件下带领人民进行的新的伟大革命,是推动经济社会发展的强大动力。当前,我国经济社会生活中存在的不少深层次矛盾和问题,归根到底要靠深化改革来解决。在新世纪新阶段,科学发展观的提出为我们指明了改革发展的方向。以科学发展观为指导,继续深化改革,进一步解放和发展生产力,推动体制机制创新,从而把经济社会发展切实转入全面可持续发展的轨道。 相似文献
19.
本文从社会基本矛盾和生产力本身两方面入手论述了邓小平关于我国社会发展的动力问题。认为改革是解决社会主义社会基本矛盾的重要手段,科学技术是促进生产力内涵量增长的关键因素。社会主义社会在全面推进改革的同时,要大力实施科教兴国战略。 相似文献
20.
张亮 《思茅师范高等专科学校学报》2012,28(1):38-41
近年来,西方史学界开始关注现代早期的警务发展状况。一些学者认为,在探究欧洲城市的发展过程中,很难抛开对城市警务的研究。近年来的研究也表明,在18世纪下半期,欧洲城市警务经历了较大幅度的变革,这主要表现在城市巡逻队数量的减少,并逐渐被专业的警察队伍取代。但在一些城市,也有居民通过自发组织形成＂半专业＂的治安队伍。从历史的角度来看,警察队伍从非专业逐步转变为专业化经历了一个非常复杂的过程。 相似文献