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Hidetaka KUROKI 《Frontiers of Mechanical Engineering》2016,11(1):26-32
After Archimedes and Vitruvius era, for more than 2000 years, it has been believed that the displaced water measurement of golden crown is impossible, and at his Eureka moment, Archimedes discovered the law of buoyancy (Proposition 7 of his principles) and proved the theft of a goldsmith by weighing the golden crown in water.A previous study showed that a small amount of displaced water was able to be measured with enough accuracy by the introduced method. Archimedes measured the weight of displaced water. He did not find the law of buoyancy but rather specific gravity of things at the moment.After which, Archimedes continued to measure the specific gravity of various solids and fluids. Through these measurements, he reached the discovery of the law of buoyancy directly by experiment. In this paper, the process to the discovery of Archimedes’ principle (Proposition 5) is presented. 相似文献
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齿轮高速干式滚切工艺取消了切削油/液的使用,是一种绿色高效的齿轮制造工艺,其成形过程分析是提升该滚齿工艺性能的有效途径。基于金属切削工艺仿真软件Deform3D建立了齿轮高速干式滚切过程的有限元仿真模型;进行了齿轮高速干式滚切材料去除过程的数值仿真分析,获得了不同参数条件下齿轮高速干式滚切过程中切屑的变形规律,以及切削力与切削温度的分布规律,分析并确定了影响滚切性能的主要参数。研究结果为齿轮高速干式滚切工艺参数优化提供了理论和方法支撑。 相似文献
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本文简要介绍了电厂锅炉引送风机调速的必要性,指出了变频调速的优点;对电厂锅炉引送风机采用变频调速后,进行了投资与效益分析。 相似文献
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Traceability and correlation in roundness measurement 总被引:1,自引:0,他引:1
A new method for the calibration of Flick standards for roundness measuring instruments has been developed through the use of a Form Talysurf stylus instrument. The method incorporates circular fits and the convolution of the standardized probe geometry over the fitted arcs using the “Kilroy's Cat” function. The method yields stable results, and an error budget documents the low uncertainty of the method. Major uncertainty contributors are the traceability of the Form Talysurf and the roughness of the Flick standard. It is shown that the tip radius has a significant effect on the results obtained in roundness measurement, even on such simple artifacts as the Flick standard. This underlines the importance of implementing a standardized tip radius. The influence of Gaussian versus 2RC filters is also documented. 相似文献
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提出了一种基于双能量源、变转速容积调速的电动叉车势能回收系统方案,建立了势能回收系统和势能回收效率的数学模型,设计了电机转速模糊PI控制系统,给出了势能回收系统的控制策略。利用AMESim和MATLAB软件进行了势能回收系统仿真分析,最后通过实车实验研究来检验仿真模型的有效性和仿真结果的正确性。研究结果表明,模糊PI控制系统的控制效果优于传统PI控制器的
控制效果,该控制策略能实现势能的高效率回收,达到控制目的。 相似文献
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CKD公司自成立以来,一直致力于自动化技术的研究开发,已开发了许多省资源、省成本的产品,并运用高新技术,积极地投入与新时代相适应的产品研究开发.CKD坚持以产业和环境相和谐为目标,不断为人类美好的生活环境作出自己的贡献.本文介绍CKD公司在新产品开发中的主要原则. 相似文献