共查询到20条相似文献，搜索用时 109 毫秒
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蔡韬 《昆明师范高等专科学校学报》2003,25(4):91-94
根据销售量、单位毛利、期间固定成本、债务利息四个因素的不同状态，得到了相应的杠杆系数表达式，并把杠杆系数模型推广为更接近企业实际情况的模型，采用逐步增加变化因素的方法，讨论了三个方案间杠杆系数表达式的内在联系。 相似文献
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马伟 《九江职业技术学院学报》2014,(3):33-34
在财务管理课程中,杠杆系数的学习对高职高专学生既是重点也是难点。学生普遍反映无法记忆和运用杠杆系数公式。本文通过将经营杠杆系数、财务杠杆系数、总杠杆系数的公式用简单的图形展示,采取串讲的形式,有助于学生对三个杠杆系数的理解、记忆和运用。 相似文献
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"给我一个支点,我就能撬动地球。"这是科学家阿基米德的一句名言。实际上,用杠杆撬动地球是不可能的,但是这反映了阿基米德发现杠杆原理后的兴奋心情。在生产、生活中,几乎每一台机器或器具都少不了杠杆,就是在我们人体中也有许许多多的杠杆在起作用。拿起一件东西,弯一下腰,甚至翘一下脚尖都与人体的杠杆有关。那么如何提高学生运用杠杆知识来解决实际问题的能力呢? 相似文献
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郑国营 《中国基础教育研究》2008,4(7)
问题：杠杆在人类的生活中有着广泛的应用，其中有省力的，也有省距离的。对于省力的杠杆，还有最省力的问题，也就是说，对于省力的杠杆，如果力作用在不同的地方，沿着不同的方向，那么仍然有作用力最小的问题。 相似文献
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杠杆的装置不同,机械效率会有所变化,可以小于1,还可以大于1。我国古代使用桔槔提水,充分利用了杠杆、水桶等的重力势能,能使桔槔的机械效率接近1。 相似文献
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本节主要包括两个内容：第一、认识杠杆，会正确画出力臂；第二、做研究杠杆平衡条件的实验。讲授什么叫杠杆?关于杠杆的五个名词与画力臂的方法。学生实验研究杠杆平衡条件，求解有关杠杆的简单问题。大纲对本节知识要求比较高，在简单机械这章中三个要求理解的内容这节就占两个。对学生空间想象能力、抽象能力、实验能力和控制变量的方法研究物理问题的能力要求也很高。 相似文献
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杜建华 《中小学实验与装备》2022,(2):54-56
在课堂教学中发现,学生对于杠杆平衡条件的结果及运用都可以掌握,但对于杠杆在非水平位置下力臂的认知和测量还存在着盲区,本文通过自制教具杠杆力臂测量仪,并使用它测量四种不同位置下杠杆的力臂和异形杠杆的力臂,加深学生对杠杆平衡条件的整体性理解. 相似文献
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There are more and more research on active control in the application of civil structure. However, some problems such as the drive levers design, optimization and control law problems restricted its application development. In this work, we presented a kind of piezoelectric drive lever to convert pulling force to pressure without flexural moments based on characteristics of the piezoelectric pile, using the genetic algorithm to optimize the layout of the driving lever, which greatly improved the efficiency. Then an active control experiment on a three-layer intelligence space structure was carried out. The experimental data show that the intelligent structures can produce through active control greatly inhibitive effects on the correspondingly controlled modal displacement and acceleration. Spectral analysis shows that the corresponding modal damping coefficient can be improved to different degrees. 相似文献
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袁凯 《成都航空职业技术学院学报》2021,37(1):39-41
振动是直升机飞行中常发生的故障之一,严重影响直升机的飞行安全。某型直升机在试飞过程中,连续出现多架左座总桨距操纵杆振动偏大的故障,给正在开展的试飞工作带来了极大的困难。针对该故障通过测振分析、试验和对比其它同型号直升机,准确判断出导致问题发生的原因,从而采取相应的改进措施并进行试飞验证,最终使得直升机总桨距操纵杆振动水平大大降低,消除了质量安全隐患,确保了该型直升机的操纵可靠性,并为后续类似问题提供了解决思路。 相似文献
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刘兴云 《南阳师范学院学报》2006,5(8):89-91
唐政府运用经济杠杆对官员进行激励,制定考评标准与官员的奖惩挂钩。物质激励对促进官员尽心尽职、效忠李唐王朝起到了一定作用,但这种单纯的物质刺激并不能完全保证官员能忠于皇权,“安史之乱”的发生就充分证明了这一点。 相似文献
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夏春艳 《邢台职业技术学院学报》2005,22(6):54-55
财务杠杆是指企业利用负债来调节权益资本收益的手段，合理的运用财务杠杆能给企业带来额外的收益．本文主要从财务杠杆损益来研究财务杠杆的巨大作用，对企业的理财人员有一定的参考价值。 相似文献
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制作了一个基于电感传感器原理的微小位移测量装置,将测量结果与光杠杆的测量结果相比较,发现用电感传感器测量微小位移时,灵敏度、线性度和测量范围相互制约。但在一定范围内,它的测量精度比光杠杆的更高。 相似文献
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基于多年实践探索与多国调研,OECD提出了有效提升学前教育质量的五大国家政策杠杆,该政策杠杆体系的构建基于OECD学前教育发展战略与学前教育质量评价观两个重要方面。长期调研与多国实践的有效性、强化学前教育质量保障的政府职能、终身学习理念的贯彻是OECD学前教育质量政策杠杆的突出特点。英国、挪威、瑞典、葡萄牙、芬兰、斯洛伐克、韩国、日本近年来根据各自国情与学前教育发展状况,聚焦某一政策杠杆,采取具体措施和行动来推动本国学前教育质量提升,取得了宝贵实践经验。 相似文献
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吴丽华 《湖州职业技术学院学报》2009,7(1):29-32
在《工程力学》教学中,如何正确进行杆件的内力分析是一个难点,以对称性原理为例,通过分析、学习、推进、深入四个层次将层次教学法在杆件内力求解中的运用进行了详细阐述,提出了新的解题思路,培养了学生分析问题的能力,有利于该课程的教学。 相似文献
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针对音乐欣赏多媒体课件制作的特殊性,着重强调了影像编配的重要,并提出和论证了编配影像的三个层次,即：“音与画合”、“身与心合”、“人与天合”。 相似文献
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Attention to core concepts in science and engineering in early education has grown recently, and understanding levers as force amplifiers can be recognized as one of these. Previous studies focused on two-sided levers and do not provide sufficient information about children's knowledge of levers as force amplifiers, nor about their learning and its support from an education perspective. It is important to consider load distance and force distance separately, as may be done in one-sided levers, to understand children's knowledge of levers as “simple machines” thoroughly. Moreover, children's zone of proximal development and the possibilities to foster their knowledge should be explored to understand important features of teaching. We thus directed two studies with 6- to 7-year-old children. In study 1, we conducted a paper-and-pencil test in the context of wheelbarrows (N = 370; age M = 6.62). We investigated whether it is possible to empirically separate the features load, load distance, and force distance as well as to determine their level of difficulty. Our study showed that children's concepts of the three aspects load, load distance, and force distance are fragmented, with children finding it continuously more difficult to judge load, load distance, and force distance correctly. In study 2, we developed a 20-min intervention with a controlled 2 × 2 pre-post follow-up design for exploring the zone of proximal development of 304 6- to 7-year-old children in the domain of one-sided levers as force amplifiers, focusing on force distance and load distance. We implemented a structured learning environment that encouraged the children to manipulate wheelbarrows and supported them with pictures and/or verbal prompts. 6- to 7-year-old children had a higher learning gain when they were exposed to scaffolds that combined pictures and verbal prompts in the posttest as well as in the follow-up test four weeks later compared to the control group. 相似文献
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John J. Fitzpatrick 《European Journal of Engineering Education》2017,42(6):916-926
This paper questions if engineering educators are producing engineers that are accelerating humanity along an unsustainable path. Even though technology and engineering are important drivers in trying to move humanity towards an environmentally sustainable paradigm, the paper suggests that maybe the most important levers and challenges lie in the economic and social domains. Short case studies of energy efficiency, the experience of the industrialist Ray Anderson and the authors own reflection of teaching chemical engineering students are used to highlight this. Engineering/technological innovation may not be enough and is often counteracted by the rebound effect and the current dominant neoclassical economic paradigm. The paper discusses what engineering educators can do to produce sustainability informed engineers who are better able to engage with the economic and social dimensions of sustainability. Some suggestions for engaging engineering students with the economic and social dimensions of environmental sustainability are provided. Engineers must somehow find ways, not just to influence technological levers (which are very important) but also to influence economic and social levers so that changes in economic and social behaviours can complement and facilitate technological change in moving humanity to an environmentally sustainable paradigm. 相似文献