蛇纹石和油酸作为润滑油添加剂的减摩抗磨性能

利用高能球磨机制备平均粒径约1 μm的蛇纹石超细粉体,并将其与油酸按质量比2∶1混合分散到PAO10基础油中,利用四球试验机探究其作为润滑油添加剂的减摩抗磨性能,利用白光干涉仪分析磨斑表面三维形貌,并用EDAX对磨斑表面元素进行分析。结果表明：蛇纹石与油酸混合加入基础油中具有更好的减摩抗磨效果;蛇纹石粉体与油酸混合后能够在摩擦副表面形成含有Si、Mg元素的修复膜,而单一的蛇纹石粉体在摩擦过程中不能成膜,这是因为,油酸作为分散剂能够吸附摩擦过程中产生的金属磨粒并使其分散到润滑油里,减少磨粒对摩擦表面造成的磨粒磨损;油酸有机修饰层吸附到蛇纹石颗粒表面,改善了蛇纹石颗粒在基础油中的分散性。     

一种新型含氮杂环润滑添加剂的摩擦学特性研究

通过四球试验机、环块试验机和万能摩擦磨损试验机,考察了制备的新型无硫磷含氮杂环润滑添加剂在液体石蜡基础油中的摩擦学性能,采用扫描电子显微镜和X射线光电子能谱仪分析了磨斑表面形貌及典型元素的化学状态。结果表明:该添加剂能显著增加基础油的承载能力,降低长磨实验的磨斑直径和环块实验的摩擦系数,并在摩擦过程中发生了摩擦化学反应,在摩擦表面形成了以氧化亚铁、有机氮化物和含氮金属配合物等为主要成分的摩擦反应膜,从而有效提高了基础油的摩擦学性能。     

纳米Fe_3O_4/油酸添加剂对磨损表面的修饰作用

采用水热法合成了在液体石蜡中具有良好亲和性和稳定性的Fe3O4/油酸(OA)纳米粒子。四球测试实验结果表明:Fe3O4/OA纳米粒子作为液体石蜡添加剂具有良好的摩擦学性能。当Fe3O4/OA的添加量为0.25%时,可使摩擦因数和磨斑直径分别减小68.2%和16.9%。试球磨斑表面的SEM分析表明:Fe3O4/OA纳米粒子在磨损表面微观缺陷区域有良好的表面修饰作用,避免了摩擦副的直接接触,减少了摩擦界面的黏着磨损,进而有效地提高了液体石蜡的摩擦学性能。     

油酸修饰Mn2+掺杂CuS纳米微粒的摩擦磨损性能

合成油酸修饰的CuS纳米微粒以及Mn2+掺杂CuS纳米微粒。TEM研究表明,制备的微粒粒径大约为10nm,具有良好的油分散性和稳定性。作为润滑油添加剂加入到液体石蜡中,考察2种纳米微粒的摩擦磨损性能,结果表明,油酸修饰的纳米微粒具有良好的抗磨性能和承载能力,含0.1%(质量分数)油酸修饰的Mn2+掺杂CuS纳米微粒的液体石蜡润滑时,可使磨斑直径降低30%,最大极压承载能力增加40%。通过SEM对摩擦表面的形貌观察,可知含Mn2+掺杂CuS纳米粒子的液体石蜡润滑时的磨痕较浅,明显优于含未掺杂的CuS纳米微粒的液体石蜡。     

表面修饰CuS纳米颗粒的合成及其摩擦学性能研究

在无水乙醇与蒸馏水混合溶剂中合成了油酸修饰的CuS纳米颗粒,根据表面修饰剂与产物CuS的摩尔比不同,分别制备出了油酸与CuS纳米颗粒的摩尔比为0.5∶1,1∶1,2∶1,3∶1的产物。在FALEX-6型四球试验机上考察了其作为润滑油添加剂在液体石蜡中的摩擦学性能,并用透射电子显微镜(TEM)对磨斑表面形貌进行分析。结果表明:在添加剂质量分数都为0.5%时,当油酸与CuS纳米颗粒的摩尔比为2∶1时,磨斑直径下降最大,抗磨效果达到最好;当油酸与CuS的摩尔比为1∶1,摩擦因数为最小值,减摩效果达到最好。     

纳米Sn粒子的制备及其作润滑油添加剂的摩擦学性能研究

用化学还原法制备了表面经油酸修饰的纳米Sn粒子,并在透射电镜(TEM)下观测到所制备的纳米Sn粒子呈球形、平均粒径为20 nm。在MSR-10D四球摩擦磨损试验机上考察了纳米Sn粒子作为CF-4 15W/40润滑油添加剂的摩擦学性能,并在扫描电子显微镜(SEM)和能谱分析仪(EDS)上对钢球磨斑表面进行了形貌观测和表层成分分析。试验结果表明,纳米Sn粒子作为润滑油添加剂具有一定的减摩性能和较好的抗磨性能,当所添加的体积分数仅为0.1%时,添加纳米Sn粒子润滑油的摩擦力比基础油降低了16.64%,其磨斑直径比基础油减小了38.4%。分析认为,纳米Sn粒子通过隔离摩擦表面而改善了润滑油的减摩抗磨性能。     

含氮杂环硼酸酯的合成及其摩擦学性能

通过分子设计,合成了含氮杂环硼酸酯,利用红外光谱确定了目标产物的分子结构.通过四球摩擦磨损试验机考察了含氮杂环硼酸酯作为润滑油添加剂在液体石蜡中的摩擦学性能,并采用场发射扫描电子显微镜观察分析了钢球磨斑表面形貌.结果表明:含氮杂环硼酸酯在液体石蜡中的添加量为1.0 % 时,最大无卡咬负荷为744.8 N,较纯液体石蜡增加了90.0 %,摩擦因数和磨斑直径分别为0.035和0.39 mm,分别降低了60.2 %和40.0 % .含氮杂环硼酸酯作为液体石蜡的减摩抗磨添加剂改善了摩擦副表面的擦伤程度,减轻了钢球表面磨损.     

改性蒙脱石微粒在润滑油中分散稳定性对其摩擦学性能的影响

采用油胺、油酸、KH550、十六烷基三甲基溴化铵(CTAB)4种改性剂对经预处理的蒙脱石进行亲油性改性处理,研究分散剂添加量对改性蒙脱石在油液中分散稳定性的影响,并在四球摩擦磨损试验机上考察改性蒙脱石在油液中的分散情况对其摩擦学性能的影响。接触角与红外光谱分析结果表明,CTAB对蒙脱石的亲油性改性效果最优;吸光度测试结果表明,分散剂质量分数为6%时改性蒙脱石在油液中分散效果最佳。摩擦试验结果表明:蒙脱石在油液中的分散情况对其摩擦学性能影响很大,未添加分散剂的CTAB改性蒙脱石在基础油中分散不太稳定,摩擦因数相较于基础油仅降低了9.27%,加入分散剂后摩擦因数和磨斑直径相对于基础油分别降低了19.21%和40.29%。扫描电镜分析结果表明,在摩擦过程中蒙脱石微粒易沉积在磨损表面的低凹处,形成一层保护薄膜,起到降低接触面损伤和一定的修复作用,但蒙脱石微粒分散不好时则易发生团聚,增加表面磨粒磨损,降低其修复作用。     

核壳型硼酸钙/SiO2复合微球的制备及摩擦学性能研究

以硼砂、硝酸钙和正硅酸乙酯为原料,在温和条件下制备核壳型硼酸钙/SiO2复合微粒。利用透射电镜(TEM)、X射线衍射(XRD)和红外光谱(FT0IR)研究复合微球的结构,发现SiO2包覆于硼酸钙的表面。将油酸修饰的复合微粒分散于液体石蜡中,利用四球摩擦试验机在载荷392 N、转速1 450 r/min、时间30 min的条件下考察其摩擦学性能。结果表明,该复合微粒具有良好的摩擦学性能,其中质量分数1.0%的复合微粒可使液体石蜡的磨斑直径从0.7 mm降低到0.5 mm,摩擦因数从0.09降低到0.05。含硼酸钙/SiO2复合微粒的液体石蜡润滑时,磨痕表面生成含B、Fe和Si的摩擦膜,从而起到减摩抗磨的作用。     

电镀废液回收纳米铜粉作为润滑添加剂的摩擦学性能研究

以化学还原法从电镀铜废液中回收的纳米铜粉为固体润滑油添加剂,在四球式摩擦磨损试验机上研究纳米铜粉的加入量对润滑油摩擦学性能的影响。采用SEM、EDAX等分析磨斑表面,初步探讨纳米铜粉抗磨减摩机制。结果表明:纳米铜粉的添加显著提高基础油的抗磨减摩性能,当纳米铜粉加入量为0.3%(质量分数)时,其摩擦因数和磨斑直径分别比基础油减小33.4%和19%。含纳米铜粉润滑油在高载荷下具有更好的抗磨减摩性能。纳米铜粉在摩擦过程中抗磨减摩机制主要为填充作用和沉积自修复膜作用机制。     

Minimal Realization of Linear Graph Models for Multi-physics Systems

An engineering system may consist of several different types of components,belonging to such physical"domains"as mechanical,electrical,fluid,and thermal.It is t...     

INTEGRAL EQUATION METHOD＇S APPLICATION IN HOLE-EDGE STRESS OF COMPOSITE MATERIAL PLATE WITH DIFFERENT SHAPED HOLES

The strength of composite plate with different hole-shapes is always one of the most important but complicated issues in the application of the composite material. The holes will lead to mutations and discontinuity to the structure. So the hole-edge stress concentration is always a serious phenomenon. And the phenomenon makes the structure strength decrease very quickly to form dangerous weak points. Most partial damage begins from these weak points. According to the complex variable functions theory, the accurate boundary condition of composite plate with different hole-shapes is founded by conformal mapping method to settle the boundary condition problem of complex hole-shapes. Composite plate with commonly hole-shapes in engineering is studied by several complex variable stress fimction. The boundary integral equations are founded based on exact boundary conditions. Then the exact hole-edge stress analytic solution of composite plate with rectangle holes and wing manholes is resolved. Both of offset axis loadings and its influences on the stress concentration coefficient of the hole-edge are discussed. And comparisons of different loads along various offset axis on the hole-edge stress distribution of orthotropic plate with rectangle hole or wing manhole are made. It can be concluded that hole-edge with continuous variable curvatures might help to decrease the stress concentration coefficient; and smaller angle of outer load and fiber can decrease the stress peak value.     

Non-monotonic material contrast in scanning ion and scanning electron images

30 keV Ga⁺ focused ion beam induced secondary electron (iSE) imaging was used to determine the relative contrast between several materials. The iSE signal compared from C, Si, Al, Ti, Cr, Ni, Cu, Mo, Ag, and W metal layers does not decrease with an increase in target atomic number Z₂, and shows a non-monotonic relationship between contrast and Z₂. The non-monotonic relationship is attributed to periodic fluctuations of the stopping power and sputter yield inherent to the ion–solid interactions. In addition, material contrast from electron-induced secondary electron (eSE) and backscattered electron (BSE) images using scanning electron microscopy (SEM) also shows non-monotonic contrast as a function of Z₂, following the periodic behavior of the stopping power for electron–solid interactions. A comparison of the iSE and eSE results shows similar relative contrast between the metal layers, and not complementary contrast as conventionally understood. These similarities in the contrast behavior can be attributed to similarities in the periodic and non-monotonic function defined by incident particle–solid interaction theory.     

Short-Term Relay Quality Prediction Algorithm Based on Long and Short-Term Memory

The fraction defective of semi-finished products is predicted to optimize the process of relay production lines, by which production quality and productivity ar...     

End-to-End Multiview Gesture Recognition for Autonomous Car Parking System

The use of hand gestures can be the most intuitive human-machine interaction medium.The early approaches for hand gesture recognition used device-based methods....     

Application of Feature Extraction through Convolution Neural Networks and SVM Classifier for Robust Grading of Apples

This paper proposes a novel grading method of apples,in an automated grading device that uses convolutional neural networks to extract the size,color,texture,an...     

分布动态载荷识别的抗噪处理

针对正交多项式频域法在用多种响应对矩形薄板进行载荷识别中抗噪性较差的问题,综合运用平均法、矩阵预处理和奇异值截断法等方法对之进行改善,并引入空间映射的思想,将该方法的应用范围拓展为复杂的模型.利用仿真算例,证实了该方法具有较好的抗噪性.     

基于MELTAC-N平台的核电厂安全级DCS环网研究与测试

针对工程实践中环网通讯相关问题的处理缺乏理论基础及国产化安全级DCS平台的开发缺乏成熟经验借鉴问题,对基于MELTAC-N平台核电厂安全级DCS环网的软硬件实现进行了研究。提出了安全级DCS环网双环网冗余设计、光切换开关设计等硬件设计方法,以及以RPR协议为基础,采用全数据收发策略的软件设计方法。在CPR1000安全级DCS平台上对安全级DCS环网的可靠性及实时性进行了评价,并进行了容错能力、响应时间及响应时间稳定性测试验证实验。结果表明,基于MELTAC-N平台安全级DCS环网软硬件设计具有较好的容错能力及响应时间稳定性。     

The laboratory simulation of abrasive wear

Abrasive wear has long been recognised as one of the most potentially serious tribological problems facing the operators of many types of plant and machinery; several industrial surveys have indicated that wear by abrasion can be responsible for more than 50% of unscheduled machine and plant stoppages. Locating the operating point of a tribological contact in an appropriate operational ‚map’︁ can provide a useful guide to the likely nature and origins of the surface degradation experienced in use, though care must be exercised in choosing the most suitable parameters for the axes of the plot. Laboratory testing of materials and simulations of machine contacts are carried out for a number of purposes; at one level for the very practical aims of ranking candidate materials or surface hardening treatments in order of their wear resistance, or in an attempt to predict wear lives under field conditions. More fundamentally, tests may be aimed at elucidating the essential physical mechanisms of surface damage and loss, with the longer term aim of building an analytical and predictive model of the wear process itself. In many cases, component surface damage is brought about by the ingress of hard, particulate matter into machine bearing or sealing clearances. These may be running dry although, more usually, a lubricant or service fluid is present at the interface. A number of standardised wear test geometries and procedures have been established for both two- and three-body wear situations, and these are briefly described. Although abrasive wear is often modelled as following an ‚Archard’︁ equation (i.e. a linear increase in material loss with both load and time, and an inverse dependence on specimen hardness) both industrial experience and laboratory tests of particularly lubricated contacts show that this is not always the case: increasing the hardness differential in an abrasively contaminated lubricated pair may not always reduce the rate of damage to the harder surface.     

ANGULAR DISTORTION ALLOWABLE VALUE AND ASSESS METHOD OF WELD ON COKE TOWER

A graph as the new engineering method for estimate the safety of bulging deformation of coke tower is proposed. Through stresses analysis of circumferential weld of coke tower and comparing the stresses produced by pressure with heat stress of steady state, residual stress, bending stress produced by both itself weight and wind loads, it showed that the stresses produced by pressure on the angle distortion are the main factor of equivalent stress of the combined stress. After comparing four kinds of stress controlling conditions, the relation to stress with depth of angular distortion, grade of curvature of angular distortion and half of region of angular distortion has been inferred. Graph of deformation allowable value of coke tower for different condition by angular distortion and half of region of angular distortion has been plotted. The five steps for its engineering use have been explained. The lighter the grade of curvature is, the larger of bulge allowance, may be, and the bigger of depth of angular distortion may pose too. For the coke tower with a popular structure of Dg 5 400 mm×28 mm, the result by graph is nearly more than the result of two formulas formed by other research, the error is less than 7.0%. But, the graph can be easily applied to different size of angular distortion.