射频磁控溅射WS_2-Ag复合薄膜的组织结构及环境摩擦磨损特性

采用射频磁控溅射方法在高速钢基体上制备WS2-Ag复合薄膜.用能谱(EDS)、X射线衍射(XRD)、扫描电镜(SEM)等对薄膜的成分、组织结构和形貌进行了表征;用划痕仪和球-盘式摩擦仪分别测试薄膜的结合力和大气及真空环境下的摩擦学性能.结果表明,Ag含量为3.23%～5.78%的WS2-Ag复合薄膜具有非晶态结构.Ag的掺入可使WS2薄膜平滑、致密,提高薄膜与基体的结合力,降低薄膜的摩擦因数和摩擦学特性环境敏感性.复合薄膜的耐磨性比纯WS2更加优异,Ag含量5.05%的复合薄膜具有最佳摩擦学性能,其在大气和真空中的磨损率分别为1.06×10-6和0.72×10-6 mm3/(N·m).     

溅射沉积MoS2薄膜中掺杂Ti对其结构与性能的影响研究

采用非平衡磁控溅射沉积技术制备纯MoS2和不同Ti掺杂量的MoS2-Ti复合薄膜。用SEM和XRD对薄膜的形貌和结构进行分析,用纳米划痕仪测试薄膜与基底间的附着力,用球-盘摩擦试验机评价薄膜在大气和真空环境中的摩擦学性能。研究结果表明:在溅射沉积MoS2薄膜过程中掺杂金属Ti,有效地阻断了MoS2疏松、多孔柱状晶的优势生长,从而生成组织结构致密、无定形态的薄膜,提高了其与基底间的附着力。掺Ti复合薄膜在大气和真空环境中的摩擦学性能都得到显著改善,真空环境中10%Ti含量的薄膜耐磨寿命最长,是纯MoS2膜的37倍,大气环境中20%Ti含量的薄膜耐磨寿命最长,是纯MoS2膜的67倍。     

W-C-S-Mo复合薄膜的制备及力学和摩擦学性能

利用磁控溅射与磁过滤阴极真空电弧（MS/FCVA）复合沉积法，在不同偏压下在单晶Si基体上制备W-C-S-Mo四元复合薄膜；分析沉积偏压对薄膜纳米硬度、弹性模量和膜基结合力等力学性能的影响；在潮湿大气、真空环境下研究偏压对薄膜摩擦学性能的影响。结果表明，薄膜硬度、弹性模量和附着力随着沉积负偏压的增大呈现先增大后减小的趋势，在偏压-100 V时薄膜力学性能最好；负偏压-100 V下制备的W-C-S-Mo四元复合薄膜样品在潮湿大气和真空环境下均具有较好的摩擦学性能，拉曼测试发现，W-C-S-Mo复合薄膜在潮湿大气环境中的润滑作用主要由DLC提供，而在真空环境中薄膜中的软质相MoS2晶粒起润滑作用。     

靶功率对射频磁控溅射制备MoS_2-Sb_2O_3复合薄膜结构和性能的影响

采用射频磁控溅射技术制备MoS2-Sb2O3复合薄膜,研究靶功率对薄膜性能和结构的影响。利用XRD、XRF分析薄膜的成分和结构,用CSM薄膜综合性能仪测试薄膜的硬度及附着力,通过承载力试验测试薄膜的承载性能,使用真空球-盘摩擦试验机测试真空和大气下薄膜的摩擦因数及耐磨寿命。结果表明:使用射频磁控溅射制备的MoS2-Sb2O3复合薄膜具有准非晶结构,其薄膜结构和成分受沉积时的靶功率影响;MoS2-Sb2O3复合薄膜在真空下具有比大气下更稳定的摩擦学性能,更长的耐磨寿命;提高溅射原子能量能有效地提高MoS2-Sb2O3复合薄膜的承载性能,减少薄膜的内应力,提高薄膜的附着力,提高薄膜的耐磨寿命。     

接地簧片级进模废料回跳及单边90°弯曲回弹的调整

我厂最近设计加工制造了一副接地簧片级进模。该模具冲压材料为QSn6．5-0．1(锡青铜),材料厚度为0．2mm,零件见图1,排样见图2。该模具在加工装配完成后经过试模发现该模具主要存在以下两个问题:     

接地簧片级进模废料回跳及单边90°弯曲回弹的调整

我厂最近设计加工制造了一副接地簧片级进模。该模具冲压材料为QSn6．5—0．1（锡青铜），材料厚度为0．2mm，零件见图1，排样见图2。该模具在加工装配完成后经过试模发现该模具主要存在以下两个问题：     

沉积温度对非平衡磁控溅射MoS2-Ti复合薄膜的结构与性能影响研究

采用非平衡磁控溅射沉积技术制备MoS2-Ti复合薄膜,研究了沉积温度对薄膜的结构和性能的影响。利用SEM、XRF和XRD分析薄膜的形貌、成分和晶相结构,用CSEM薄膜综合性能测试仪测试薄膜的硬度和与基底间的附着力,用球-盘摩擦试验机和真空环模系统评价薄膜的真空摩擦磨损性能。结果表明:沉积温度升高薄膜中S和Mo原子比从1.72升高至1.76,Ti质量分数从8.2%降低至6.7%,薄膜从明显的(002)基面优势取向向多晶态转变,晶粒尺寸变大,棱面膜含量增多;薄膜的硬度、与基底间的附着力都随沉积温度的升高而降低,沉积温度为200℃时薄膜性能降低明显,硬度从4GPa降至2GPa,薄膜与基底间附着力从80mN以上降至35mN;薄膜在真空环境中的减摩作用不受沉积温度影响,摩擦因数平均值为0.02,波动范围为0.01～0.04,薄膜耐磨寿命随沉积温度升高而降低,50℃和100℃薄膜耐磨寿命相差不多,200℃薄膜样品耐磨寿命很差,是50℃和100℃薄膜样品的1/8～1/7。     

沉积温度及膜厚对离子镀银膜结构及摩擦学性能的影响

采用离子镀在不锈钢和45钢基体表面低温沉积银薄膜.利用X射线衍射仪(XRD)、扫描电镜(SEM)和真空摩擦试验机对低温沉积银膜的晶体结构、表面形貌和摩擦学性能进行了研究.结果表明:银膜的择优取向度随着沉积时间的延长和基体温度的降低具有明显变化;在-147℃沉积6 min条件下制备的银膜为表层具有(200)择优取向及底层为(111)择优取向的双层结构;银膜在载荷较高时也有较好的摩擦学性能.     

纯稀土Ce对A1-4．5％Cu铸造性能的影响

用对比的方法，研究了纯稀土Ce变质处理对A1—4．5％Cu合金的线收缩、热裂和流动性等铸造性能的影响规律。试验结果表明：稀土元素Ce的加入可明显改善A1—4．5％Cu合金的铸造性能。在纯稀土Ce加入量小于0．2％时，随Ce加入量的增加，A1．4．5％Cu合金的线收缩降低，热裂时最大应力增加，流动性增加；当纯稀土Ce的含量为0．2％时，A1-4．5％Cu合金的铸造性能达到最好；当Ce的含量大于0．2％时，A1-4．5％Cu合金的铸造性能反而降低；纯稀土Ce的最佳加入量为0．2％。     

柴油机活塞环表面类金刚石薄膜在模拟工况下摩擦学性能

大缸径、长冲程的大功率柴油机的活塞环-缸套摩擦副易发生异常磨损,使柴油机动力性能丧失,甚至发生拉缸等重大事故,通过先进的表面处理技术可显著改善活塞环-缸套摩擦副的润滑条件,提高活塞环-缸套摩擦副的摩擦学性能。采用阴极电弧离子镀技术在铬-陶瓷复合镀(CKS)活塞环表面制备厚度为7 μm的DLC薄膜,研究CKS活塞环表面的DLC薄膜在柴油机模拟工况下的摩擦学性能。结果表明：在干摩擦、室温贫油和高温贫油的工况下,CKS活塞环表面的DLC薄膜可以显著减小活塞环-缸套摩擦副对摩的摩擦因数,降低缸套的磨损;摩擦过程中DLC薄膜与润滑油的协同润滑作用以及DLC薄膜的石墨化是改善活塞环-缸套摩擦副摩擦学性能的主要原因。     

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。     

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....     

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.     

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.