不同离子液体润滑条件下BCN薄膜摩擦学性能研究

利用中频磁控溅射技术,分别溅射硼靶和石墨靶,在单晶硅衬底上制备BCN薄膜;采用原子力显微镜(AFM)对薄膜的表面形貌进行分析;在1-正丁基-3-甲基咪唑四氟硼酸盐(L104)和1-正己基-3-乙基咪唑六氟磷酸盐(L-P206)离子液体润滑条件下,利用CSM摩擦磨损试验机考察BCN薄膜/钢球摩擦副的摩擦磨损性能;利用电化学腐蚀方法考察薄膜在离子液中的耐腐蚀性能.实验结果表明:所制备的BCN薄膜均匀、致密,表面粗糙度小;在离子液体润滑剂润滑下,BCN薄膜表现出良好的抗磨减摩性能和抗腐蚀性能;与L-P206离子液润滑剂相比,BCN薄膜在L104离子液体润滑剂润滑下的摩擦学性能更好,这可能与L104离子液体自身的分子结构及其腐蚀性弱有关.     

不同介质下CrN_X薄膜的摩擦学特性研究

采用电弧离子镀技术在45#钢衬底表面沉积了CrNX薄膜.用显微硬度计测试了薄膜的硬度,用X射线衍射仪分析了薄膜的相结构,用球-盘式摩擦磨损试验机评价了在不同介质条件下(干摩擦、水润滑、油润滑)CrNX薄膜的摩擦学性能,用表面轮廓仪测试了磨痕处的磨痕轮廓,用扫描电镜(SEM)观察了薄膜磨痕形貌.结果表明,相对于干摩擦,水润滑和油润滑条件下,CrNX薄膜的摩擦因数和磨痕深度都有明显降低的趋势.干摩擦条件下薄膜主要表现为磨粒磨损;水润滑条件下,主要表现为腐蚀磨损;油润滑条件下由于油膜在两摩擦表面的吸附,薄膜几乎无磨损.     

Fe_3O_4磁性纳米流体在磁场下的摩擦学性能研究

通过在水基切削液和MNF润滑条件下分别进行的摩擦磨损试验可以发现,MNF中Fe_3O_4磁性纳米颗粒(MNPs)的存在能够显著减小摩擦系数、上式样磨球的磨损体积以及下式样的磨痕宽度,从而改善摩擦学性能。在施加不同大小的磁场后再次进行摩擦磨损试验发现,外界磁场能够引导MNPs至对磨区域,形成一层持久稳定的润滑膜,进一步改善MNF的摩擦学性能,并且外界磁场越强,改善效果越明显。     

磨损条件对轴承钢低温离子渗硫层摩擦学行为的影响

采用低温离子渗硫技术在GCr15钢的表面制备了FeS固体润滑薄膜。在球-盘摩擦磨损试验机上对比研究了GCr15钢渗硫在不同磨损条件(工况和润滑条件)下的摩擦学性能。利用SEM观察分析了磨损表面形貌及成分,利用XPS分析了磨损表面边界润滑膜化合物的价态。结果表明:在改变工况的情况下,转速的增加会使FeS层作用下降,载荷的增加也会降低FeS层抗磨性能,但在一定转速下都存在一个可充分发挥FeS层减摩特性的载荷。使用极压抗磨添加剂不能改善渗硫层的减摩抗磨性能,但选用合适的添加剂可增强渗硫处理件的承载能力,提高其在恶劣工况下的磨损寿命。     

油-气润滑对点接触副滑动摩擦行为的影响

在MFT-3000型多功能摩擦磨损试验机上,以球/盘模型为考察对象开展油-气润滑点接触副滑动摩擦试验,并与相同工况下滴油润滑和干摩擦试验进行对比。利用白光干涉形貌仪、扫描电镜、X射线能量色散谱(EDS)和铁谱分析设备对磨痕轮廓、表面形貌、化学元素组成以及磨粒形状进行表征、分析。结果表明:在油-气润滑工况下,当供油量不足时,随供油量增加,摩擦因数、磨损量和磨痕参数等均出现明显减小趋势,但润滑性能较滴油润滑差;当摩擦副间润滑油充足,且供气速度达到一定值时,与滴油润滑相比,油-气润滑能够获得更低的摩擦因数,但磨痕形貌变化较轻微;在较低的滑动速度和载荷下,油-气润滑点接触滑动摩擦不会发生氧化磨损,油-气润滑散热功效对摩擦行为无明显影响,与滴油润滑以及干摩擦下磨损机制相同,均为磨粒磨损,摩擦过程中产生的磨屑形状以碎屑状和片状为主,伴随着少数长条状。     

不同温湿度下风电轴承表面防护DLC薄膜微动摩擦特性

针对湿热环境下风电绝缘轴承的微动磨损失效问题，采用等离子体增强化学气相沉积工艺在绝缘涂层Al₂O₃表面沉积类金刚石碳(DLC)薄膜，研究温湿度对其微动摩擦特性的影响。结果表明：DLC薄膜在适当高温下均具有良好的摩擦学性能，在湿度为80%RH时的平均摩擦因数较小；温湿度较高的环境有利于降低DLC薄膜的微动磨损程度，提高绝缘轴承的防护程度；对磨痕处进行拉曼光谱分析表明摩擦过程中DLC薄膜磨痕表面杂化键sp²/sp³比值均大幅上升，且薄膜发生了石墨化转变。DLC薄膜在高温下的低摩擦行为主要是由于DLC薄膜表面石墨化过渡层和磨损表面石墨化的协同作用。     

TiN、CrN的环境摩擦磨损对比研究

采用直流叠加脉冲偏压电弧离子镀技术在45钢表面沉积了TiN、CrN薄膜。用显微硬度计测试了薄膜的硬度,用划痕仪测量了薄膜的膜基结合力,用球-盘式摩擦磨损试验机评价了不同介质条件下（干摩擦、水润滑、油润滑）TiN、CrN薄膜的摩擦学特性,用表面轮廓仪测试了薄膜磨痕处的磨损轮廓,用扫描电镜（SEM）观察了薄膜磨痕形貌。结果表明,相对于干摩擦条件下,在水润滑和油润滑条件下TiN和CrN薄膜的摩擦因数和磨痕深度都有所降低。在相同的介质条件下,CrN薄膜的摩擦因数和磨痕深度始终小于TiN薄膜。     

溅射沉积MoS_2/Sb_2O_3复合润滑膜的摩擦磨损过程与失效分析

采用UMT-2型球-盘摩擦磨损试验机研究溅射沉积MoS2/Sb2O3复合固体润滑膜的滑动摩擦磨损寿命,采用显微镜分析球-盘摩擦副在不同磨损阶段的磨损形貌与磨损状况,并对磨痕位置S、Mo元素进行XPS分析。结果表明:在摩擦磨损寿命试验过程中,摩擦副的接触方式最开始的点接触逐步过渡到面接触;MoS2固体润滑膜对滑动摩擦副的延寿作用是基底材料表面的有效厚度润滑膜及MoS2对摩擦偶件(钢球)的转移;机械磨损的剪切剥离效应是润滑失效的主要原因,MoS2的氧化在一定程度上加剧了润滑失效的进程。     

具有表面类金刚石膜高速钢的耐磨性能

在高速钢基体上分别进行了制备类金刚石(DLC)膜和浸硫氮化两种表面处理,并以铸铁为对偶件,用MM200磨损试验机比较了经两种不同表面处理高速钢的耐磨性能,用扫描电子显微镜观察了磨痕形貌并分析了磨损机理。结果表明:在转速200 r·min~(-1)、载荷50 N的条件下,不论在油润滑状态还是在干摩擦状态,具有DLC膜高速钢的耐磨性能明显比浸硫氮化处理的好。     

FeS/铜基复合材料摩擦磨损性能研究

通过粉末冶金方法制备含Fe S的铜基复合材料,采用M-200型摩擦磨损试验机,分别在干摩擦和浸油干摩擦条件下对其摩擦磨损性能进行检测。结果表明:Fe S/铜基复合材料在2种工况条件下均具有一定的减摩效果,并且随着Fe S含量的增多,摩擦副摩擦因数越来越小;在浸油干摩擦条件下,当Fe S含量较高时,润滑油与Fe S转移膜共同作用形成液-固润滑膜,边界润滑效果较好。     

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...     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

Fifth International Summer School on Screw-Theory Based Methods in Robotics

正3-11 September,2014University of Bologna,Bologna,Italy www.summerscrews.org summerscrews2014.ing.unibo.it SUMMER 20SCREWS 14In 2014,our screw-theory school comes to the world's oldest university.In early September,Summer Screws'14 will gather six experts in the application of screw theory in robotics and up to 40 participants at the University of Bologna,Bologna,Italy.The school will teach attendees how to apply existing methods and empower them to develop new ones in their own research.The basic theoretical notions will be introduced in a rigorous manner,emphasizing examples,applications,and exercises.Scholarships are available.     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

INDUSTRIAL ENGINEERING AND VISUALISATION-A PRODUCT DEVELOPMENT PERSPECTIVE

Taking the actual project of teaching and researching process for example, the relationship between the industrial engineering and product development is discussed. And use the novel visualization technology to support the industrial engineering and product development. How to use the new computer modeling and simulating technologies to support the product development and industrial engineering, is introduced especially. The support includes both domestic products and industrial systems. The visualization and computer technologies take a very important role in some system or multi-direction modeling, those technologies mentioned above can help the industrial engineers study the effect of design on the whole life circle, including the producing steps. So the engineers can avoid making the wrong decision which may cause bad effects on the whole industrial engineering.     

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...