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。     

纳米WS2和TiN对GCr15钢摩擦磨损性能的影响

以纳米WS_2和TiN为添加剂,研究不同纳米材料及含量对基础油500SN减摩抗磨性能的影响。试验结果显示,在添加纳米材料后,润滑油的减摩抗磨性能有了明显提升,磨损类型也发生了明显的改变,其中在添加纳米TiN后的磨损类型由磨粒磨损变为黏着磨损,在添加纳米WS_2变为黏着磨损与磨粒磨损共存;随着纳米粒子质量分数的增加,润滑油的减摩抗磨特性先提升后下降,其中0.3%质量分数的纳米TiN的减摩抗磨效果最好,相比基础油,可以使摩擦因数下降5%～8%,磨斑直径下降26%～32%。     

蒙脱石和坡缕石纳米润滑油添加剂的摩擦学性能

将KH550偶联剂修饰的纳米蒙脱石和纳米坡缕石,分别按质量比3%添加到150N基础油中制备2种纳米润滑油分散体系,用激光粒度分析仪、TEM、IR表征纳米添加剂的分散稳定性,在MMU-10G摩擦磨损试验机上测试2种纳米润滑油对45#钢的减摩抗磨性能,用SEM和EDX等分析摩擦试样表面成分与形貌的变化及影响摩擦学性能的机制。结果表明:纳米蒙脱石平均粒径较小,在150N基础油中分散更稳定;2种纳米润滑油相比纯基础油润滑时的平均摩擦因数和磨损量均明显下降,其中纳米蒙脱石润滑油的抗磨减摩性能最好;2种纳米润滑油润滑时摩擦试样表面分别生成了含蒙脱石和坡缕石特征元素的自修复膜层,其中蒙脱石特征元素含量相对较高,说明纳米蒙脱石摩擦学性能更好。     

纳米蒙脱石添加剂对45~#钢摩擦副摩擦学性能的影响

将KH550偶联剂修饰的纳米蒙脱石(MMT)按不同质量分数加入150N基础油中,制备质量分数1%~5%的5种纳米MMT润滑油体系,采用MMU-10G摩擦磨损试验机考察纳米MMT对45#钢摩擦副减摩抗磨性能的影响,采用SEM和EDX等分析试样形貌与表面元素成分的变化,分析影响摩擦学性能的机制。结果表明:质量分数3%的纳米MMT润滑油和具有最好的抗磨减摩性能,相对于基础油润滑体系,可使金属摩擦副磨损失重量最小降低45.5%;所有试样表面均形成了以MMT特征元素和Fe元素为主体组成的自修复膜层,使试样磨损损失获得补偿,其中质量分数3%的纳米MMT润滑油润滑时摩擦副表面MMT特征元素的含量最高,故试样磨损率最小;纳米MMT润滑体系润滑时的摩擦因数均低于纯基础油,但是不同含量的纳米MMT对改善45#钢摩擦副的减摩性没有明显的区别。     

纳米氢氧化锰抗磨减磨添加剂的研究

用乙醇超临界干燥技术制得粒子大小约为40nm的晶状氢氧化锰,用TEM及XBD对该产物进行了表征,用环块及四球摩擦磨损试验机测定了纳米氢氧化锰作润滑油添加剂的摩擦学性能,发现:将一定量的纳米氢氧化锰及分散剂山梨醇单硬脂酸酯加入500SN基础油中可提高其抗磨减磨性能及承载能力。纳米氢氧化锰有一最佳加入量,超过此量油品最大无卡咬负荷将减小。吸咐有分散剂的纳米氢氧化锰在摩擦表面的沉积及随后的剪切作用形成了具有抗磨减摩性能的膜。     

纳米铜添加工艺对润滑油摩擦学性能的影响

探讨了纳米铜不同分散工艺和添加量对润滑油摩擦学性能的影响。分别采用超声分散和球磨分散工艺，将3种不同工艺制备的纳米铜材料溶于SF15W／40机油中，在T-11摩擦磨损试验机上进行摩擦学性能试验。结果表明，其中一种纳米铜能够提高基础油的减摩性能，采用超声分散比采用球磨分散的减摩性能好。随着纳米铜浓度的增加抗磨性能有明显的提高，分析认为纳米铜在摩擦表面的沉积有利于提高摩擦学性能。     

聚合十六烷氧基硼酸钾的合成及作为润滑油抗磨减摩添加剂的摩擦学性能

本文合成了一种含硼及钾的油溶性化合物-聚合十六烷氧基硼酸钾并将其用作润滑油抗磨减摩添加剂,用四球及环块摩擦试验机研究了它的摩擦学性能.结果发现:500SN基础油的抗磨性能得到明显改善,其承载能力明显提高,摩擦系数明显降低,有—最佳添加剂含量,超过此量,油品的承载能力不升反降.将磨斑分别在石油醚及蒸馏水中用超声波清洗后用扫描电子显微镜表征,结果发现磨斑表面存在有含硼沉积物.聚合十六烷氧基硼酸钾在表面发生了摩擦化学反应,如分解、缩合等,这些反应产物形成了一层具有抗磨减摩性能的膜.     

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。     

油酸改性层状硅酸钠的摩擦学性能研究

运用正交试验设计对层状硅酸钠进行了改性,确定了最佳的改性条件,并对改性层状硅酸钠进行了表征。把经过改性的层状硅酸钠作为润滑添加剂加入150SN基础油中,利用摩擦磨损试验机考察其摩擦学性能。结果表明:经过改性的层状硅酸钠作为润滑添加剂可以显著提高150SN基础油的承载能力和减摩抗磨性能。     

油酸修饰纳米氟化镧的摩擦学性能

以油酸为修饰剂制备表面改性的氟化镧纳米粒子,在环块式摩擦磨损试验机上考察氟化镧纳米粒子在150N基础油中的摩擦学性能,借助透射电镜(TEM)、金相显微镜及X射线衍射仪(XRD),分别对磨损试样的表面形貌和元素成分进行观察和分析,探讨表面修饰氟化镧纳米添加剂的抗磨减摩机制.结果表明:油酸修饰的氟化镧纳米粒子在150N基础油中减摩抗磨效果明显,与纯基础油润滑相比,在250 N压力和450 r/min转速条件下,质量分数2％的氟化镧纳米粒子在稳定磨损阶段可使45#钢试样摩擦因数降低40％,总失重降低43.75％.EDX分析表明,氟化镧纳米粒子在摩擦过程中在磨损表面生成了自修复膜.     

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.     

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.     

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....     

Limits of topographic measurement by the scanning tunnelling and atomic force microscopes

Parameters describing the topographic character of a surface (height, surface wavelength, slope and curvature) can be derived from equivalent sinusoidal profiles. The response of a surface-measuring instrument may be modelled in terms of instrument parameters such as stylus radius, and scanning range and resolution. The performance of the instrument may then be mapped as a zone in amplitude-wavelength (AW) space to show the sinusoidal profiles it is capable of measuring. In a first-order analysis the STM and AFM are considered as equivalent to contact-stylus instruments with a notional stylus radius equal to the tip radius plus the gap. Comparisons between different instruments and types of instrument are readily made by mapping in AW space. The error arising from convolution of the sinusoidal profile with that of the finite tip may be quantified and plotted as contours in AW space.