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刘雪丰 《湖南师范大学社会科学学报》2003,32(2):11-14
科学技术的性质如何,不仅应有横向的剖析,还要有纵向的梳理,才能提出接近真理的判断。从历史发展的视角看,大体可以划分为三个阶段:轻视科学技术阶段、积极运用科学技术阶段和自学控制科学技术阶段。与当代新兴科学技术的特点紧密相联系,以当代新兴科学技术与首先的内在联系为基石,科学技术从工具价值理性走向道德价值理性,进路的关键在于,提升科学工作的良心和道德责任感,强化企业的外部伦理约束和自我道德限制,使国家随之成为对科学发展和运用进行全局的、长期的战略规划与管理的综合性实体。 相似文献
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应用SolidWorks软件建立护套线剥线机主传动机构刀架三维实体模型,根据剥线机工作时的受力情况,利用有限元软件对刀架进行静力学和疲劳强度分析,获得刀架各项静力学参数图和疲劳寿命情况。该分析结果为护套线剥线机的设计提供理论依据,也为后续剥线机结构优化提供了技术支持。 相似文献
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给出了确定成形车刀截形尺寸公差的计算法,并通过实例与查表法进行了比较,从而为准确、合理地确定截形尺寸公差提供了理论依据. 相似文献
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Statistical and Fourier analysis methods of time series representing fluctuations of stock market in general and Indian stock markets in particular are well known. This work is motivated by a recent paper by Guharay [Operations Research and Financial Engineering, Princeton University, Princeton, NJ, preprint, 2002] where he has studied trends in the S & P 500 for various time periods using wavelet tools. Our paper deals with a few Indian and Saudi stock prices and return fluctuation for a certain period of time. The main objective of the analysis is to understand the dynamics of the Indian and Saudi stock markets. We look for similarities, point of abrupt changes, normalized data, return, volatility, graph, pure and noise part, correlation lengths, and signal-to-noise ratio. 相似文献
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A novel precision vibration-assisted micro-engraving system was developed by the integration of fast tool servo and ultrasonic elliptical vibration system, in which the flexure hinge was designed to avoid backlash and PID control algorithm was established to guarantee specific precision. Apart from experimental validation of the performance of the system, various micro-V-grooves cutting experiments on aluminum alloy, ferrous material and hard cutting material were performed, in which Kistler force sensor was used to measure cutting force. Through experiments, it was clear that the vibration-assisted micro-engraving system can ensure good quality of micro-V-grooves and reduce cutting force by about 60% compared with traditional removal process without ultrasonic vibration. 相似文献
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Compacted graphite cast iron (CGI) has been the material for high-power diesel engines recently, but its increased strength causes poor machinability. In this study, coated and uncoated carbide tools were used in dry milling experiment and FEM simulation to study the machinability of CGI and wear behaviour of tools. The experimental and FEM simulation results show that coated tool has great advantage in dry milling of CGI. SEM and EDS analysis of tool wear indicate the wear morphology and wear mechanism. Adhesive wear is the main mechanism to cause un-coated tool wear, while abrasive wear and delamination wear are the main mechanism to cause coated tool wear. Stress and temperature distribution in FEM simulation help to understand the wear mechanism including the reason for coating peeled off. 相似文献
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王婷 《商丘职业技术学院学报》2011,10(1):82-83
单音节手部动词指需要用手参与才能完成的具体动作的动词。持具类手部动词是手部动词的一个小类,其特点是在完成动作时必须使用身体器官以外的工具。持具类手部动词的两个典型句式:含使用工具的句式为"NP1+用+GN+V+C+NP2",不含使用工具的句式为"NP1+V+C+NP2"。 相似文献