共查询到20条相似文献,搜索用时 62 毫秒
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固体润滑技术及其工程应用 总被引:2,自引:0,他引:2
叙述了固体润滑技术的发展,介绍了固体润滑的特点及常用固体润滑材料,重点探讨了固体润滑技术在机械传动零部件、机械加工以及特殊工况下的应用. 相似文献
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近年来,高分辨固体核磁共振技术(SSNMR)发展迅速,其在化学材料研究领域的应用价值日益显现。本文第一部分简述了化学研究中常用的SSNMR脉冲高分辨技术,包括同核和异核去偶技术以及偶极重聚技术等。第二部分结合具体的实验方法和实例,重点介绍SSNMR技术在材料研究中的应用。首先,使用一维谱实验、二维化学位移相关谱实验来实现分子化学结构和聚集态结构的研究;然后,通过同核偶极偶合常数的测量来计算原子核间的距离信息;此外,交叉极化定量实验可以实现样品体系结构和组分的定量表征;最后,通过对异核偶极偶合常数的测量、线型分析以及弛豫时间的测量等方法来实现固体材料分子动力学行为的研究。 相似文献
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固体NMR是研究高分子结构和动力学的有效手段,特别是固体高分辨NMR谱仪技术的进步及其各种实验方法的发展,推动这方面研究进展,本文简述固体高分辨NMR的各种实验技术,并且给出该技术在高分子研究中的应用。 相似文献
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以轴承的固体润滑为研究对象,进行了轴承跑合试验、轴承寿命及性能试验研究分析,为采用固体润滑技术解决轴承空间润滑问题提供了依据。 相似文献
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固体力学作为力学的一个重要分支,是研究固体材料受力时内部应力应变规律以及变形破坏规律的学科。随着有限元理论的发展以及计算机在固体力学领域的广泛应用,计算固体力学在现代得到了迅速的发展。在20世纪50年代左右,固体力学又衍生出断裂力学以及复合材料力学这两个分支。20世纪70年代,细观力学逐步发展,在材料的强度和韧性方面的研究取得了重大进展。近年来,随着中国宇航产业的蓬勃发展,为适应各种苛刻环境条件而开发新型航空材料的计算模拟需求也在不断提升。本文着眼于固体力学的发展,分析了计算固体力学在中国航空技术中的应用。 相似文献
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针对煤矿开采过程中会产生固体矸石废弃物的问题,结合煤矿开采关键设备液压支架的作用,利用固体垃圾填充置换煤炭技术,从主要结构的设计、支架整体三维建模及有限元数据分析对固体充填液压支架的设计进行研究,得出所设计固体充填液压支架满足应用要求,解决了矸石的大量输出对土地、环境、人身的影响和危害的问题,相较于普通液压支架,带固体充填夯实功能的液压支架在一定程度上提升了承载能力和稳定性. 相似文献
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DISCUSSING ON SOLID ABRASIVE LAPPING PATH 总被引:7,自引:0,他引:7
Yang Jiandong Wen XuehengChangchun Institute of Optics Fine MechanicsZhu Yanqiu Wang Lijiang Jilin University of Technology 《机械工程学报(英文版)》1997,(2)
DISCUSSINGONSOLIDABRASIVELAPPINGPATHYangJiandong,WenXuehengChangchunInstituteofOpticsandFineMechanicsZhuYanqiu,WangLijiangJil... 相似文献
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0 IamODUCTIONFollowing the experimental data reported by Li.Pman['j on the existence of boundary layers over aflat plate, some interesting facts are observed:(l )There is a viscous sublayer developed near the wall which has practically zero fluid velocity inthe vicinity Of the wall(refer to Fig. I a). This sublayer may be calculated by substituting V = 0. 05, aridthe boundary layer is calculated by taking V = 3.5 where V = y (U/Zus )"' is a non-dimensionalsimilarity transformation funct… 相似文献
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Sanjay Agarwal 《Machining Science and Technology》2013,17(1):61-79
Heat produced during ceramic grinding, due to high specific energy and high wheel-workpiece friction, is critical in terms of workpiece quality. High heat generation at the grinding zone impairs the workpiece quality by inducing thermal damage in the form of surface and subsurface cracks, phase transformations, tensile residual stresses, etc. These damages can severely limit the application of ground ceramic components. Cooling and lubrication therefore, plays an important role during ceramic grinding. Conventional cutting fluids are often ineffective due to the phenomena like air barrier and film boiling effect. Further, these fluids have a direct influence both to human health and environment and therefore, being questioned in the light of economic and ecological manufacture. So, possible replacement of cutting fluids by something else is of great concern to the researchers in recent years. Demands for high operating temperatures, lower cost, longer life and better performance drive the search and use of alternative lubricants. This paper deals with an investigation on using graphite and molybdenum disulphide as solid lubricants, to reduce friction and heat generated at the grinding zone. An experimental setup has been developed, and experiments have been conducted to study the effect of using these lubricants, on tangential grinding force, specific energy and surface roughness while grinding SiC. Results indicate that there is a considerable improvement in the process performance with solid lubricant assisted grinding as compared to that of grinding in dry condition. 相似文献
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Heat produced during ceramic grinding, due to high specific energy and high wheel-workpiece friction, is critical in terms of workpiece quality. High heat generation at the grinding zone impairs the workpiece quality by inducing thermal damage in the form of surface and subsurface cracks, phase transformations, tensile residual stresses, etc. These damages can severely limit the application of ground ceramic components. Cooling and lubrication therefore, plays an important role during ceramic grinding. Conventional cutting fluids are often ineffective due to the phenomena like air barrier and film boiling effect. Further, these fluids have a direct influence both to human health and environment and therefore, being questioned in the light of economic and ecological manufacture. So, possible replacement of cutting fluids by something else is of great concern to the researchers in recent years. Demands for high operating temperatures, lower cost, longer life and better performance drive the search and use of alternative lubricants. This paper deals with an investigation on using graphite and molybdenum disulphide as solid lubricants, to reduce friction and heat generated at the grinding zone. An experimental setup has been developed, and experiments have been conducted to study the effect of using these lubricants, on tangential grinding force, specific energy and surface roughness while grinding SiC. Results indicate that there is a considerable improvement in the process performance with solid lubricant assisted grinding as compared to that of grinding in dry condition. 相似文献
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三维实体模型到有限元板壳模型的自动转换 总被引:1,自引:0,他引:1
针对板壳结构有限元分析的需要,将商用CAD软件生成的板壳结构的三维实体模型用STL文件格式输出。对其进行拓扑关系重构并进行表面网格再划分,在此基础上对单元及面进行分类,从而确定并选取有效三角形面片,并计算面片对应的厚度值及其中面位置。将这些三角形面片移动到中面位置,形成适合有限元分析的板壳中面模型。将这种板壳模型自动转换方案应用到几个实际薄壁构件的实体模型上,成功地抽取了这些板壳的中面模型。结果表明,该方法可大幅度降低生成板壳有限元模型的工作量,提高计算效率。 相似文献
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基于实体模型的虚拟微装配视觉伺服研究 总被引:1,自引:0,他引:1
微装配的主要问题是装配的器件小,装配精度高,一般用显微镜作为视觉传感器对装配运动进行控制。在大放大倍数下,显微镜的视场和景深很小,这时操作对象和操作工具就不会同时处在焦平面内,使得图像模糊,操作很难完成。利用显微镜的聚焦理论,提取对象的三维信息,构造对象的实体模型,使微装配在虚拟环境中进行,而实际环境只起监视的作用,当对象和工具不动时,虚拟操作环境不变化,而当操作对象和工具位置变化时,重构三维环境,使得虚拟环境和实际环境具有严格的位置对应关系。试验和仿真结果表明,该方法可以克服物体在显微镜下的失焦问题,而且操作方便。 相似文献
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固体发动机工况中密封圈大变形接触应力分析 总被引:3,自引:1,他引:3
从固体发动机密封结构特点和密封可靠性出发,对所研究的密封结构进行分解和简化。采用接触罚单元算法,应用ANSYS有限元分析系统软件,建立橡胶密封圈的轴对称超弹性非线性问题的三维有限元分析模型,对固体火箭发动机密封的充分必要条件及在工况中密封界面上的接触压应力分布规律进行研究。在讨论超弹性接触问题的前提下,研究密封结构承受不同燃气内压时对密封接触状态的影响。通过对这些影响规律的分析,找出造成密封失效的可能原因,为固体火箭发动机等重要场合下0形橡胶密封圈的正确选用提供一种方法。 相似文献