共查询到20条相似文献,搜索用时 78 毫秒
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合理选用润滑剂,是设备防止泄漏、节约能源、降低消耗、延长使用寿命的重要途径。 润滑剂按相状态可分为气体、液体、半固体、固体润滑剂等。目前广泛采用的是液体和半固体润滑剂,即润滑油与润滑脂。固体润滑剂正在得到推广。 从润滑油、脂的基本润滑特性来看,二者的润滑机理基本上是相同的。如在滑动轴承中加入润滑剂,轴颈转动时带着油或脂顺着转动方向从大口走向小口,产生呈收敛楔形吸附油膜而支承轴颈运转,避免或减小了轴颈与轴承内表面的接触摩擦。这里,只是润滑脂油膜的产生过程比较复杂,它是依靠轴颈转动时对脂产生足够大的剪力,使脂中的纤维骨架(由金属皂构成)发生变形以至剪断,沿剪力方向作定向排列,导致纤维骨架中含蓄的基础油(一般为矿物油)流动,成为粘度接近基础油的流体吸附油膜。另外,为了保证润滑剂适 相似文献
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产品的商品化设计在产品的开发设计中占有举足轻重的地位,一个产品在成功地推向市场,离不开商品化设计这一阶段,它是在产品推向市场前对产品进一步完善和完美的一个过程。本文论述了商品化设计前期-实用化设计中的人机工程设计,商品化设计中的降低成本设计,产品造型设计和包装设计等,及其在产品设计开发中的应用。 相似文献
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在分析创新、快速设计是现代企业制胜的法宝基础上,将快速设计的思想与概念创新设计自动化工具——DARFAD相结合,利用网络技术,将客户、企业、供应商等有机集成在一起,提出协同商品设计的概念,并给出系统模型。 相似文献
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The irradiation effects of thinning a sample of a Cu-Zn-Al shape memory alloy to electron transparency by a Ga(+) focused ion beam were investigated. This thinning method was compared with conventional electropolishing and Ar(+) ion milling. No implanted Ga was detected but surface FCC precipitation was found as a result of the focused ion beam sample preparation. Decreasing the irradiation dose by lowering the energy and current of the Ga(+) ions did not lead to a complete disappearance of the FCC structure. The latter could only be removed after gentle Ar(+) ion milling of the sample. It was further concluded that the precipitation of the FCC is independent of the crystallographic orientation of the surface. 相似文献
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A study of high-resolution ADF imaging in uncorrected and aberration-corrected STEMs was carried out by multislice simulation. The presence of amorphous layers at the surface of a crystalline specimen is shown to significantly alter the visibility of the atomic columns. After propagating through an amorphous layer a portion of the beam passes without any alteration while scattered electrons introduce a Gaussian background. The dependence of the image contrast on the crystal structure, orientation and the types of the atoms present in the crystal was studied. In the case of uncorrected probes an amorphous layer thicker than 200 A is necessary to achieve considerable reduction of the visibility of the atomic columns, but with aberration-corrected probes only 60 A is necessary. With changes in defocus, crystalline specimens with amorphous layers on the top can also be imaged and high-resolution ADF images can be obtained. An amorphous layer at the beam entry surface affects the ADF image more than that of an amorphous layer at the exit surface. Approximately linear reduction of the contrast (with a slop of 1) is expected with increased thickness of amorphous layer. 相似文献
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Rüdiger Holinski 《Wear》1979,56(1):147-154
The influence of boundary layers on friction was investigated using a Bartel lubrimeter. Boundary layers have only a limited life and are re-formed in the contact area. A minimum specific pressure is required to deposit a solid lubricant film. The addition of MoS2 lowers friction and frictional temperature. Some antiwear extreme pressure additives increase friction and others reduce friction and friction temperature. Some boundary layers tenaciously adhere to the surface and are only slowly worn away. 相似文献
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A. V. Kolubaev S. Yu. Tarasov O. V. Sizova E. A. Kolubaev Yu. F. Ivanov 《Journal of Friction and Wear》2007,28(6):514-520
The methods of speckle-interferometry, electron, optic, and atom-force microscopy were used to study the structure and regularities of deformation of surface layers on metals and alloys in friction. The causes of deformation localization are analyzed. An explanation of the strong wear resistance of Hadfield steel is proposed using data on the evolution of the surface layer structure. 相似文献
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目前,商品混凝土在我国正以势不可挡的势头飞速发展,并以质量稳定、供应及时、污染少等特点,得到了大力推广,与传统的现场搅拌相比具有明显的优势.因此,商品混凝土搅拌站应运而生,尤其是随着禁止城市现场搅拌禁令的实施,商品混凝土搅拌站必定会迎来发展的春天. 相似文献
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Solid carbon-graphite materials are widely used in a variety of arduous tribological applications in which their ability to run either unlubricated or in the presence of fluids with unpropitious tribological properties can be exploited. The usual arrangement in such devices as seals and bearings is to run a carbon component against a much harder metallic or ceramic counterface of appropriately low surface roughness. In practice, it is often observed in these circumstances that, although the initial wear rate of the relatively soft carbon is high, a satisfactory long-term performance can be achieved if, and only if, a stable layer of carbonaceous material is generated both on the trace of the carbon and as a transfer layer on the harder counterface: in the absence of this film the high initial wear rate continues unabated. The range of carbon materials available commercially is large, but can be classified by the extent to which they have been graphitized—those with a higher graphitic content have a lower elastic modulus and generally higher wear rate than less graphitic specimens. In this paper, we consider the development of the contact conditions with component life and how these can be associated with the alleviation of the initial severity through the development of a cushioning layer of consolidated wear debris and thus offer an explanation of the experimental observations in terms of a contact mechanics model. 相似文献
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The properties of boride layers on steels alloyed with chromium, molybdenum or vanadium are presented first. The properties considered are: chemical composition, phase composition, microstructure, thickness, hardness and roughness. The wear test results shown were obtained with different test rigs, so that the main wear mechanisms could be recognized. The results reveal that adhesion, abrasion and surface fatigue are strongly influenced by the solution of the elements of the differently alloyed steels in the boride layers, while tribooxidation is influenced to a minor extent 相似文献