采用电化学交流阻抗等测试方法研究无机富锌与有机富锌涂层在海水腐蚀环境中的失效机理

本文采用M398交流阻抗系统对无机富锌和有机富锌涂层进行电化学交流阻抗谱测定,采用截面电镜照片分析不同浸泡时间涂层微观形貌变化,采用EDAX分析涂层浸泡前后腐蚀产物。通过以上3种手段比较分析特定的无机富锌和有机富锌涂层在3.5%NaCl水溶液中的失效机理。     

富硒、锌纳豆芽孢杆菌的选育

实验表明纳豆芽孢杆菌能够进行无机硒、锌的生物转化,纳豆芽孢杆菌转化无机硒、锌的最大浓度均为1.0×10-5mol/L;过量的无机硒、锌对纳豆芽孢杆菌具有明显的毒害作用,少量的无机硒、锌可促进纳豆芽孢杆菌的生长.通过正交试验优化出富硒、锌纳豆的最佳发酵条件为每kg大豆中添加硒1.0×10-6maol,锌1.0×10-6mol,接种量7%,培养温度42℃,培养时间19h.经检测,此条件下发酵的纳豆硒含量为6.58μmol/kg,锌含量为7.39μmol/kg;无机硒、锌的转化率分别为65.8%和73.9%;每克富硒、锌纳豆的纳豆激酶酶活为1195.96IU.     

基于摩擦学带沟槽滑块的摩擦系数试验研究

根据摩擦学原理,针对往复式滑块运动特点,设计了一种带沟槽滑块,并进行了理论计算,得出了油膜厚度方程和油膜压力方程。通过对其摩擦系数试验研究,表明该结构能够使滑块在运动过程中得到良好的润滑,在一定程度上解决了摩擦副之间的摩擦、磨损问题。     

湿平整轧制摩擦系数计算技术的研究

针对以往平整机组湿平整轧制过程中因摩擦系数不准而导致平整轧制压力的预报精度偏低的问题,在实用平整轧制压力模型的基础上,充分结合某连退机组的设备与湿平整轧制的工艺特点,采用分类细化方法,提出了一套适合于湿平整轧制的摩擦系数计算新技术,利用BPC系统的实际数据编制相关软件对摩擦系数进行有序化回归处理,给出了不同轧制工况下机组的摩擦系数,有效地提高了轧制压力的预报精度,保证了产品质量。相关技术经现场使用,效果良好,具有进一步推广应用的价值。     

环氧富锌预涂底漆在和谐D2机车上的应用

通过环氧富锌预涂底漆极好的焊接施工性、防腐蚀性和与钢材极好的附着力等优越性能以及在同车公司铁路机车钢材预处理上的应用介绍,总结了该预涂底漆的施工工艺和注意事项,提高了铁路电力机车的防腐性能,达到延长机车车辆使用寿命的要求,这项工艺已应用在HXD2系列机车顶盖上,使用效果非常好。     

水下振源体膜板空蚀的研究

水下大功率振源体工作一段时间后膜板中心附近位置出现空蚀现象,分析了膜板产生空蚀的原因及空蚀相关理论,通过提高材料抗空蚀性能和阴极保护两种方法来减轻空蚀破坏.提高材料抗空蚀性能包括改变材料、增加壁厚和提高表面粗糙度;阴极保护采用喷涂无机富锌涂料.     

扣件螺母的临界锈蚀厚度计算方法研究

在实现铁路扣件养护设备大型、高效、自动化的过程中,扣件螺母表面所允许的锈蚀层厚度,即螺母的临界锈蚀厚度成为设备研发中的一个重要技术参数,文中根据该公司在研项目,对螺母临界锈蚀厚度的计算方法进行了有意义的探索,形成了一套由合理简化、公式推导、绘图计算组成的简明的分析计算方法,同时用实例进行了计算过程的阐述,为铁路扣件养护...     

高温下金属材料厚度的激光超声检测研究

针对高温条件下金属材料厚度测量的问题,使用激光超声技术,首先利用一束脉冲激光在金属材料中扫描激发超声,并使用激光测振仪在固定点探测,获得了从金属样品底面反射的体纵波脉冲信号的渡越时间,随后通过线性拟合获得了样品厚度及体纵波波速,并在室温到480℃的温度范围内实现了多块20号合金钢样品的厚度测量.多温度下、不同厚度的多样...     

The influence of the slide-to-roll ratio on the friction coefficient and film thickness of EHD point contacts under steady state and transient conditions

The effect of different slide-to-roll ratios has been experimentally investigated under steady state and transient conditions using a steel ball in contact with the plane surface of a glass disc. Under transient conditions the entraining velocity has been varied with a sinusoidal law at two different frequencies. Measurements of the friction force and film thickness using optical interferometry have been made.For the same working conditions, different friction coefficient trends found for positive and negative slide-to-roll ratios can be related to different film thickness values and shapes. The combination of different thermal effects could be a possible explanation for the obtained results.     

伸缩臂叉车伸缩臂强度测试及臂架间摩擦因数的计算

伸缩臂叉车作为一种远距离作业车辆具有广泛的用途.伸缩臂作为其主要作业部件,对其正常作业起到至关重要的作用.在伸缩臂的设计过程中,伸缩臂之间的摩擦因数是一个重要的参数,是伸缩臂各部件设计与选型的基础.伸缩臂的强度关系到伸缩臂叉车的作业能力与安全,对同类型车辆的设计也有借鉴作用.文中对伸缩臂液压缸压力进行测量,通过数值计算得出摩擦因数和伸缩臂强度.     

The significance and use of the friction coefficient

The quantity known as the friction coefficient (or ‘coefficient of friction’) has long been used in science and engineering. It is easy to define, but not easy to understand on a fundamental level. Conceptually defined as the ratio of two forces acting, respectively, perpendicular and parallel to an interface between two bodies under relative motion or impending relative motion, this dimensionless quantity turns out to be convenient for depicting the relative ease with which materials slide over one another under particular circumstances. Despite the fact that both static and kinetic friction coefficients can be measured with little difficulty under laboratory conditions, the time- and condition-dependent characteristics of friction coefficients associated with both clean and lubricated surfaces have proven exceedingly difficult to predict a priori from first principles.The shaky nature of friction's fundamental underpinnings, has not prevented investigators from compiling lists of friction coefficients and publishing them for general use. Problems often arise, however, when engineers attempt to use tabulated friction coefficients to solve specific problems in mechanical design or failure analysis. The systems-dependence of frictional behavior is sometimes ignored, leading to misapplication of published data. This is particularly true for applications in nano-technology and others that differ from typical laboratory size scales. This paper will review the measurement and use of static and kinetic friction coefficients, discuss their usefulness, and describe the sources of frictional resistances in terms of shear localization.     

The influence of soot and dispersant on ZDDP film thickness and friction

The effect of dispersed soot in engine oils is an increasingly important issue in terms of both engine durability and fuel efficiency. Using carbon black as a soot analogue, a study has been carried out to investigate the main factors that determine the impact of soot on friction and ZDDP film formation in formulated oils. It has been found that dispersed carbon black can rapidly remove ZDDP reaction films by abrasion. However, this removal can be prevented or limited by the choice of an optimal dispersant additive.     

Optimising the design of textured surfaces for reducing lubricated friction coefficient

Under operating conditions which are unfavourable for lubrication, such as high load and low velocity, the use of textured surfaces significantly promotes the formation of a thick lubricant film and an improvement of the friction coefficient. This paper relates to the manufacture of textures using a photolithography and chemical etching process. Different surface geometries, texturing densities and depths were designed to analyse the influence of these parameters. The friction coefficient was measured in a ball‐on‐disc tribometer under different lubrication regimes, and the results have been used to develop an artificial neural network with texturing optimisation potential. © 2016 The Authors Lubrication Science published by John Wiley & Sons Ltd.     

微腔对摩擦副摩擦系数的影响机理研究

将微腔模型引入摩擦副摩擦研究,通过建立微腔的气体-压强模型,分析了摩擦副微腔对摩擦的影响机理.并尝试用所建立的模型解释载荷、摩擦副相对运动速度、环境气压、静止接触时间对摩擦系数的影响.     

Research of oil film thickness model and surface quality in cold rolling copper foil

Rolled copper foil is widely used in high frequency and speed transmission of fine line printed circuit board, because of its high strength, good toughness and high density. In this paper, a theoretical model for copper foil rolling in mixed lubrication regime was developed on the basis of the average volume flow model and asperity flattening model. A more accurate relation for the variation of the lubricant viscosity with pressure and temperature was considered. The cold rolled copper foil experiment was carried on with different viscosity of rolling oil and pass reduction. The effects of rolling oil viscosity and pass reduction on lubricant pressure, contact area ratio and film thickness ratio were studied. The calculation results agree well with the measured data from copper foil rolling experiment. For obtaining higher surface quality, the rolling oil viscosity is about 10 mm²/s, and the pass reduction is about 30%. Copyright © 2013 John Wiley & Sons, Ltd.     

往复式薄膜X射线测厚仪的研制

介绍了用于薄膜测厚的全自动往复式X射线测厚仪的研制,详述了该测厚仪的硬件组成和测厚的工作原理.该装置已成功运行在双向拉伸聚丙烯(BOPP)薄膜生产线上.     

Origins of the friction and wear properties of antiwear additives

Experimental techniques have been developed to measure the friction, antiwear film‐forming and wear properties of lubricants in rolling–sliding contact. Friction measurements show that zinc dialkyldithiophosphates (ZDDPs) and also some other phosphorus‐based additives increase friction in mixed lubrication. Film thickness measurements show that this increase in friction correlates with the thickness of antiwear film. They also reveal some of the drivers of antiwear film formation and removal. A novel wear tester is described which enables the mild wear resulting from ZDDP‐containing oils to be monitored. Copyright © 2006 John Wiley & Sons, Ltd.     

薄膜厚度和光学常数的主要测试方法

准确地测量和控制薄膜厚度和光学常数等参数,在薄膜制备和分析和应用都是极为重要的。对薄膜的厚度和光学常数测试方法作了归纳和分类,并对几种主要的测试方法作了简要的介绍,分析了各自的特点及存在的问题。在测量薄膜的厚度和光学常数时,必须根据待测样品和测量精度要求选择合适的方法。