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Objective To characterize the abrasive wear of polymer tapes in ATM (Auto Teller Machine) servicing in sand dust environment. Aethods The abrasive wear experiment of polymer tapes, PEN (polyethylene-2, 6-naphthalenedicarboxylate) and PI (polyimide), by sand dust particles is performed in ATM tribosystem. The fractal characteristics of the worn surface of polymer tapes and the corresponding wear mechanisms are examined. ReSults As main results, the worn surfaces of polymer tapes show bi-fractal characteristics, and PI tape shows higher fractal dimensions and finer wear profiles than PEN tape. Wear mechanism examination shows macro and micro ploughing and cutting grooves and micro fracture characters, which gives reasonable explanation of bi-fractal character of worn polymer tapes. Conclusion Worn polymer tape shows fractal character and bi-fractal can be used in accurately characterizing the abrasive wear of polymer tapes of ATM in sand dust environment. 相似文献
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本文在分析现有船舶机械诊断技术的基础上,针对船舶营运的特点,提出和讨论了开发船舶机械的远程集散式诊断系统的设计原则、系统构成和软件结构。 相似文献
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Objective To investigate the changes to the strike extent of piston to cylinder after engine supercharge design. Methods The lubrication model between the skirt of piston and liner is established by means of piston dynamics, combined with the hydrodynamic lubrication equation. Optimized numerical analysis method is employed in solving the dynamics and lubrication equations. The analyses about piston strike under two combustion gas pressures are performed. Results The peak values of maximum eccentricity under supercharge condition are much greater than under non-supercharge condition, which means a stronger impulsion of piston to cylinder wall and a greater possibility of scuffing. The horizontal velocities of piston in supercharge condition are larger, which illuminate the more unstable motion state. Conclusion The analysis gives a new conclusion. Combustion gas pressure plays an important role in the piston strike motion. Influences of supercharge should be taken into account so that the traditional product test items can be improved. 相似文献
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谢友柏 《上海交通大学学报(哲学社会科学版)》2022,(4):57-69
文章分析了1945年范内瓦·布什给美国总统罗斯福的报告,以及2020年拉什·霍尔特为报告撰写的导读以及相关评论中可能给予我国推进科技创新战略的启发。研究结果表明,从科学研究到实际应用的线性模型或象限模型都说明取得创新成果之前,有若干需要深入细致研究的不同特性,需要不同慎重对待的阶段,包括基础研究、应用研究、开发和生产经营,其中特别强调了基础研究的重要性。文章分析了以创新而不是科学研究为抓手固然有更强大的号召力,然而如果不充分研究得到创新成果前各个阶段的特点和采取适合时代进步和我国国情的有效应对措施,我们的科技创新战略将事倍功半。同时,文章也关注了这些报告和评论的重要缺陷,它们都没有提及知识在这些阶段之间流动这一极其重要的事实,没有提及控制知识流动的是对承前启后具有决定意义的、连接这些阶段的设计环节,没有提及设计的基本共同规律和要共同遵守的法则——设计科学这样一个基础研究领域,因而未能阐明知识在这些阶段中流动所产生的作用,特别是未能指出设计是知识流向创新的桥梁和纽带,设计可能使科学研究成果流向有利于社会发展的创新,也可能使科学研究成果流向危害社会的灾难。这些报告和评论未能就不同时代和不同... 相似文献
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Design for life-time performance and proper maintenance measures are usually needed to prolong the mean-time-between-failures
of complex equipments such as internal combustion engines. To reach this, it is important to obtain the information of time-varying
system performance in design stage and to identify the structural change at each moment. So a multidisciplinary model based
method is studied in this paper to unify the time-varying performance(TVP) prediction and system identification(SI) of equipments.
The related multidisciplinary model in this paper should be not only precise to give simulation results but also sensitive
to the variation of system parameters. So the varying history of system performance along with the structural change can be
obtained from the model. Then the value of system parameters can be identified by seeking roots with given detected responding
data and relationship between system responding data and system parameters. A case study on a low power gasoline engine shows
that the method presented in this paper can provide useful information for the development and maintenance of complex equipments. 相似文献
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接地面全熔化条件下冰面轮胎摩擦力的预测 总被引:1,自引:1,他引:1
依据流体动力润滑理论和热平衡原理,提出了接地面全熔化条件下冰面轮胎摩擦力的预测模型。结果表明,受不同因素的影响,摩擦系数变化趋势的模型预测同实验结果极为相似,文中分析讨论了影响摩擦力的主要因素,认杰表面模型,滑移率和界面温升等的影响应作为今后相关领域的研究重点。 相似文献
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