共查询到20条相似文献，搜索用时 296 毫秒
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针对目前细长轴车削加工工艺应用过程存在的问题,文章从实践角度出发,分析了细长轴车削加工工艺问题,并提出了具体问题的解决方法,其目的是为相关建设者提供一些理论依据。结果表明,只有在明确车削加工细长轴工件问题的情况下,才能使最具效用的加工工艺作用于工件的生产,进而提高其作用于工业化建设的质量效果。 相似文献
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通过分析W6Mo5Cr4V2(M2)高速钢的组织与性能特点,研究了高速钢刀具的热处理方法,在对不锈钢材料的细长轴车削加工的基础上,提出了高速钢刀具设计和加工工艺的实施方法 相似文献
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介绍了细长轴的切削加工特点及切削加工方法,重点论述了车削加工的装夹方式、加工车刀和撤削方法,对磨削加工的几个问题也进行了探讨。 相似文献
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单双柱立式车床的横梁，以及2m以上的滑枕等，均属刚性较弱的长导轨零件。这些零件在加工中，在夹紧力和自重力的作用下，变形较大。为了解决这些问题，我们通过对细长导轨加工变形等问题的认真分析，得出了保证加工精度的有效方法——自然夹紧发。为保证细长导轨的加工质量找到了有效途径，本文将重点分析刚性较弱的细长导轨的加工。 相似文献
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手工锯削是工科类学生必须掌握的操作技能之一，它具有操作灵活、方便、适用性广的特点。在学生实训时间很短的情况下，应从掌握正确的锯削操作方法、做好锯削前准备和注意锯削整个过程三个方面让学生又好又快的掌握这项操作技能。 相似文献
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手工锯削是工科类学生必须掌握的操作技能之一，它具有操作灵活、方便、适用性广的特点。在学生实训时间很短的情况下，应从掌握正确的锯削操作方法、做好锯削前准备和注意锯削整个过程三个方面让学生又好又快的掌握这项操作技能。 相似文献
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Hong Zhu Chuan Chen Li-Zhi Liao Michael K. Ng 《Journal of The Franklin Institute》2018,355(4):1819-1845
The core issue of multiple graphs clustering is to find clusters of vertices from graphs such that these clusters are well-separated in each graph and clusters are consistent across different graphs. The problem can be formulated as a multiple orthogonality constrained optimization model which can be shown to be a relaxation of a multiple graphs cut problem. The resulting optimization problem can be solved by a gradient flow iterative method. The convergence of the proposed iterative scheme can be established. Numerical examples are presented to demonstrate the effectiveness of the proposed method for solving multiple graphs clustering problems in terms of clustering accuracy and computational efficiency. 相似文献
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Nguyen Huu Sau Dinh Cong Huong Mai Viet Thuan 《Journal of The Franklin Institute》2021,358(1):1044-1069
This paper addresses the reachable sets bounding problem for time-delay positive singular systems subject to bounded disturbances. The time delays in the considered systems are assumed to be time-varying. Both invariant and time-varying singular systems are investigated in this paper. Existence conditions of componentwise ultimate bounds of the state vector of considered systems are derived and given in terms of the spectral abscissa of the system matrices, which are easy to be checked. The obtained results are demonstrated by two numerical examples. 相似文献
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Yong-Gui Kao Ji-Feng Guo Chang-Hong Wang Xi-Qian Sun 《Journal of The Franklin Institute》2012,349(6):1972-1988
This paper is devoted to investigating the robust stochastic exponential stability for reaction-diffusion Cohen–Grossberg neural networks (RDCGNNs) with Markovian jumping parameters and mixed delays. The parameter uncertainties are assumed to be norm bounded. The delays are assumed to be time-varying and belong to a given interval, which means that the lower and upper bounds of interval time-varying delays are available. Some criteria for delay-dependent robust exponential stability of RDCGNNs with Markovian jumping parameters are established in terms of linear matrix inequalities (LMIs), which can be easily checked by utilizing Matlab LMI toolbox. Numerical examples are provided to demonstrate the efficiency of the proposed results. 相似文献
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推理实质上是认知信息的更新方式。从信息哲学的角度,可以为演绎、归纳与溯因等三种推理方式划定界限。除了可能世界语义学,使用邻域模型也可以为认知信息的更新构造模型。有两种更新方式：交集模型和子集模型。利用交集模型可以对演绎推理作出信息论的解释。归纳推理的结论是带强度的信念。子集模型可以对科学发现的过程作出解释,从而区分演绎、归纳和溯因。邻域语义学揭示的两种信息更新方式是不同的,这是信息更新的逻辑动态学方面的新发现。 相似文献
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高校对学生能力的培养、考核,不应只是对学生书本知识记忆能力的培养和考核。高枝精品课程建设的基本宗旨应是培养学生应对未来生活挑战．应具有的基本的终身学习能力。文章以企业战略管理精品课程的建设为例．从研究课程建设的历史演进出发．得出了应从重视教学规律研究,用新的教育教学理念指导课程建设;进行教材及基础设施建设和教学内容的适时、适度更新;开展课程教学组织的设计与运行的管理：重视教学方法与手段的创新以提高实验性教学水平;通过教学活动与管理实践性活动互动,不断提高学生自主学习能力等五方面开展精品课程建设工作的观点。 相似文献
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创业者的职业生涯问题有别于一般管理者,创业者职业生涯问题的理论研究近年来受到越来越多研究者的关注。本文总结了近年来在创业者职业生涯研究和创业生涯决策研究方面的理论进展,并提出未来值得进一步研究的几个问题:(1)整合的创业者职业生涯理论研究模型有待开发。(2)个案研究将成为创业者职业生涯问题研究的重要方法;(3)不同类型创业者的职业生涯问题的异同值得进一步研究。(4)进一步开展在中国背景下创业者职业生涯问题的相关研究。 相似文献
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高校落实科学发展观就是要坚持以学生为本的理念,尤其是要理性认识高校贫困大学生成材的问题,积极构建贫困大学生成材的机制,不仅要为其成材制定经济资助机制、金钱观教育机制,而且还要为其成材制定精神激励机制和社会反馈机制。 相似文献
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David J. Teece 《Research Policy》2018,47(8):1367-1387
The value-capture problem for innovators in the digital economy involves some different challenges from those in the industrial economy. It inevitably requires understanding the dynamics of platforms and ecosystems. These challenges are amplified for enabling technologies, which are the central focus of this article. The innovator of an enabling technology has a special business model challenge because the applicability to many downstream verticals forecloses, as a practical matter, ownership of all the relevant complements. Complementary assets (vertical and lateral) in the digital context are no longer just potential value-capture mechanisms (through asset price appreciation or through preventing exposure to monopolistic bottleneck pricing by others); they may well be needed simply for the technology to function. Technological and innovational complementors present both coordination and market design challenges to the innovator that generally lead to market failure in the form of an excess of social over private returns. The low private return leads to socially sub-optimal underinvestment in future R&D that can be addressed to some extent by better strategic decision-making by the innovator and/or by far-sighted policies from government and the judiciary.The default value-capture mechanism for many enabling technologies is the licensing of trade secrets and/or patents. Licensing is shown to be a difficult business model to implement from a value-capture perspective. When injunctions for intellectual property infringement are hard to win, or even to be considered, the incentives for free riding by potential licensees are considerable. Licensing is further complicated if it involves standard essential patents, as both courts and policy makers may fail to understand that development of a standard involves components of both interoperability and technology development. If a technology standard is not treated as the embodiment of significant R&D efforts enabling substantial new downstream economic activity, then rewards are likely to be calibrated too low to support appropriate levels of future innovation. 相似文献
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J.L. Finck 《Journal of The Franklin Institute》1948,245(4):301-317
In this paper the concepts “equilibrium” and “reversibility” are examined from the standpoint of the number of independent variables which define a thermodynamic system. The endeavor is made to show that the number of independent variables which are selected is crucial to the basic concepts as well as to the second law of thermodynamics. If this number is less than the minimum required to define the system completely, the equation of state for the internal energy will be incomplete. It is our practice to employ incomplete equations of state, and this results in processes which we consider to be irreversible. The Kelvin-Planck and Clausius principles are shown to be somewhat related to the first law of thermodynamics, and their validity arises from the fact that the equations of state which are used are incomplete. If these equations were complete, that is, if the number of independent variables were not less than the minimum required to describe the systems completely, we should have complete conversion of heat into work, as well as work into heat. The difficulties in realizing complete equations are considered.The entropy concept is considered in detail, and it is shown that there are serious limitations in its application. 相似文献