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991.
Since 1940s the principal source of an antiwear additive in crankcase applications has been due to a family of additives known as zinc dialkydithiophosphate (ZDDP). In this study, we have applied a novel technique, the mini traction machine with spacer layer image mapping (MTM SLIM), to study film formation characteristics of monoblend oils containing only basestock and ZDDP and also fully forrmulated oils containing a boron antiwear additive. The purpose of this study was initially to understand the build up of ZDDP film and then to establish whether boron compounds alone could provide significant antiwear films under mixed rolling and sliding contact. 相似文献
992.
分析了饮料瓶瓶盖的结构和性能要求,对瓶盖的32腔模具设计了巧妙的脱模结构和稳定的热流道系统,并进行了强度计算论证。且在该模具制造中选用了合适的材料,提供了典型的部件加工工艺。 相似文献
993.
面向对象的柴油机燃油供给系统计算机仿真程序设计 总被引:2,自引:0,他引:2
建立了柴油机燃油供给系统计算机仿真的数学模型,提出了其面向对象的仿真设计思想和设计方法。运用该设计方法可有效提高仿真系统的可适用性、可维护性和可靠性。 相似文献
994.
995.
本文针对轴类热喷涂焊层中喷涂层、喷焊层的车削加工工艺进行分析 ,从设备调整、刀具牌号选择、刀具几何参数选择三个方面进行研究 ,对加工工艺进行改进 ,在实际生产中具有一定的价值 相似文献
996.
997.
998.
A modified Reynolds equation is derived for thin film elastohydrodynamic lubrication (TFEHL) by means of the viscous adsorption theory. This TFEHL theory can be used to explain the deviation between the measured film thickness and that predicted from the convenient elastohydrodynamic lubrication (EHL) theory under very thin film conditions. Results show that the thinner the film, the greater the ratio of the adsorption layer to the total film thickness becomes, and the greater the value of the pressure–viscosity index (z′). An inverse approach is proposed to estimate the pressure distribution based upon the film thickness measurement and to determine the pressure–viscosity index of oil film, and the thickness (δ) and the viscosity ratio (η*) of the adsorption layer in TFEHL circular contacts. Based on TFEHL theory, the inverse approach can reduce z′ error, and provides a reasonably smooth curve of pressure profile by implementing the measurement error in the film thickness. This algorithm not only estimates the pressure, but also calibrates the film shape. Consequently, it predicts z′, η*, and δ with very good accuracy. It can also be used to evaluate the lubrication performance from a film thickness map obtained from an optical EHL tester. Results show that the estimated value of z′ is in very good agreement with the experimental data. 相似文献
999.
Molecular basis of lubrication 总被引:8,自引:0,他引:8
The advent of micro-electromechanical devices (MEMs), sensors, actuators, microsystems, and nanotechnology have called to attention the effect of friction on moving parts in nano/micro devices. To take full advantage of the opportunity to sense, compute, and actuate in real time, fast-moving parts are often necessary or desirable. As the scales of the components shrink, adhesion, stiction, friction, and wear become a significant technological barrier for the successful deployment of durable devices. Most current devices in production avoid such contacts.The nature of the surface contacts, as component scale moves from macro to micro to nano, is dominated by surface forces that normally are dwarfed by mechanical loading. Therefore nanolubrication needs to take into account different factors than conventional lubrication concepts. This paper compares traditional lubrication concepts and those necessary for nanolubrication and proposes various nanometer scale thick lubricating film designs as a means to control the surface properties of surfaces at nano/micro scales.Many of the concepts derive their origin from studies and observations from the magnetic hard disk technology where a “monolayer” of lubricant protects the system and has proven to be robust and safe. Examples from magnetic hard disks will be used to illustrate some of the concepts. 相似文献
1000.
物理层密钥具有降低密钥分发、更新和维护的难度的特点,针对无线传感器网络中节点传输信息易遭受窃听攻击的问题,基于物理层安全中的"一次一密"理论,提出了一种物理层密钥生成方法,主要包含信道估计、特征提取、密钥生成与协商。在半双工通信模式下,根据信道估计阶段相干时间的长短,对训练序列的长度进行动态调整,提高信道估计的一致性。仿真试验与对比分析结果表明,窃听节点生成密钥与合法节点生成密钥的一致性始终维持在较低水平,降低了遭受窃听攻击的风险。 相似文献