激光电刷镀Ni基镀层表面形貌及相结构研究

进行了脉冲和连续Nd^2＋：YAG激光电刷镀Ni及n—Al2O3／Ni试验，利用SEM分析了镀层表面形貌，采用X射线衍射仪分析了镀层的相结构。结果表明：与普通电刷镀镀层相比，激光强化电刷镀镀层晶粒明显细化，其中镀层的晶粒尺寸减小了约5nm，且激光的连续性对Ni镀层晶粒尺寸的影响较大。激光未对Ni镀层和n-Al2O3／Ni复合镀层的晶体结构产生明显影响，但使镍晶粒在（111）晶面具有优先生长现象。     

PTFE对复合镀层摩擦特性的影响

研究了PTFE添加量对Ni基电刷镀PTFE复合镀层的摩擦特性和磨损机制的影响.采用扫描电镜、X射线衍射仪和能谱仪分析了摩擦前后的磨损表面的形貌、组织和成分变化.结果表明:PTFE添加量对复合镀层的组织和摩擦特性有较大的影响.当PTFE体积分数为3%和4%时,复合镀层的摩擦因数最小;当PTFE体积分数为2%时,复合镀层的耐磨性最好.在磨损面上富含PTFE复合层的形成和面积随PTFE添加量的变化影响了复合镀层的摩擦特性及其磨损机制.     

活塞环成型轧辊的失效分析及电刷镀表面强化工艺的研究

本文分析了活塞环成型轧辊的失效机制,在不同刷镀工艺参数下制备了Ni-P合金非晶电刷镀镀层,研究了工艺参数对镀层沉积速率、镀层组织与性能的影响,最佳工艺条件下镀层的耐磨性以及热处理后镀层性能的变化等,结果表明,在电刷电压为12V,阳极运动速度为10m/min条件下,镀层可获得最佳的组织与性能,Ni-P非晶电刷镀层经热处理后由于Ni3P的析出,使镀层硬度提高,从而提高了镀层的耐磨性。实际应用表明,经电刷镀后轧辊的使用寿命是原来的2倍。     

纳米耐磨和减摩复合镀层的研究

分析了将纳米三氧化二铝(Al2O3)和聚四氟乙烯(PTFE)颗粒加入常规电刷镀液中制备纳米耐磨和减摩复合镀层的组织、显微硬度、耐磨性和摩擦因数。结果表明：纳米颗粒的加入使复合镀层组织明显细化和致密。随着纳米Al2O3颗粒含量的增加，复合镀层的显微硬度和耐磨性有明显的提高，纳米PTFE的加入有助于减少复合镀层的摩擦因数。     

纳米复合镀层接触疲劳性能研究

利用电刷镀技术制得了n-Al2O3/Ni和n-ZrO2Ni纳米颗粒复合电刷镀层。测试了复合镀层的显微硬度和接触疲劳寿命,分析了载荷和退火处理对镀层疲劳寿命的影响。结果表明,复合镀层具有较高的显微硬度,载荷为60N和140N时,n-Al2O3/Ni复合镀层具有较高的疲劳寿命,而n-ZrO2Ni复合镀层的寿命较低。接触疲劳寿命随载荷的增加而降低,退火处理使n-Al2O3/Ni复合镀层的疲劳寿命显著降低,而使n-ZrO2/Ni复合镀层的疲劳寿命大幅度提高,是镀态时的3.8倍。n-ZrO2/Ni复合镀层的滚道面呈脆性剥落,而退火后呈塑性变形特征。     

第一讲 装备再制造技术（五）

（4）纳米复合电刷镀工艺①纳米复合电刷镀的一般工艺过程纳米颗粒复合电刷镀技术的一般工艺过程与普通电刷镀基本相同,见表7。在实际刷镀时,根据工件的材料、尺寸、表面热处理状态、技术要求、镀层厚度及工件条件等因素,正确选择纳米复合镀液体系以及镀件极性、电压（电流）大小、相对运动速度等工艺参数,合理安排工序。     

基体表面粗糙度对纳米复合镀层组织及性能的影响

采用电刷镀技术在不同表面粗糙度的W18Cr4V高速钢基体上制备了纳米PTFE和纳米WC颗粒增强的镍基复合镀层,采用扫描电镜对纳米复合镀层的表面和截面形貌进行了观察,研究了基体表面粗糙度对纳米复合镀层耐磨性、耐蚀性和结合强度的影响.结果表明:随着基体表面粗糙度的减小,纳米复合镀层的表面更加平整致密,组织更加细小均匀,镀层厚度减小,镀层中的裂纹数量减少,镀层的耐磨性、耐蚀性和结合强度均得到明显提高.     

活塞式气体压缩机阀片的化学镀Ni-P合金工艺研究

对活塞式气体压缩机的13CrMo钢阀片进行镀Ni—P工艺研究。分析了活化处理时间对化学镀Ni—P镀层结合力、热处理温度对镀层表面硬度及后处理等对锌层耐蚀性的影力规律。用优选的工艺参数对阀片进行表面强化与防蚀处理，获得了较好的效果。     

化学镀镍-磷-纳米SiC-PTFE复合镀层的组织结构与晶化动力学

采用扫描电镜、X射线衍射仪、差热分析仪等分析了化学镀镍-磷-纳米SiC-PTFE复合镀层的表面形貌和物相结构,并研究了镀层的晶化动力学。结果表明:纳米SiC、PTFE颗粒均匀地分布于复合镀层中,且SiC颗粒在镀层中发生部分团聚;随热处理温度升高,镀层由镀态下的非晶态出现晶化,并逐渐析出镍、Ni3P以及Ni3Si等晶相;与镍-磷镀层相比,这种含两种颗粒的复合镀层表现出较低的晶化起始温度与较长的晶化时间,且其晶化激活能为268kJ.mol-1。     

超细SiC对Ni-P化学合金镀层组织结构的影响

在化学镀Ni-P合金溶液中添加不同粒径的超细SiC粒子进行化学镀，制备了三种Ni-P-SiC化学复合镀层；通过扫描电镜、X射线衍射仪、透射电镜和示差扫描量热分析仪对镀层的形貌和组织结构及其转变进行了表征。结果表明：化学复合镀层镀态下为非晶态结构，在一定温度热处理后晶化产生Ni3P和镍晶体，晶化温度几乎不受SiC粒子影响；在较高温度下镍与SiC发生反应生成Ni-Si化合物，SiC粒径越小，与镍发生反应的起始温度越低；400℃热处理复合镀层的最终产物中除了镍和Ni3P以外还有Ni3Si和游离碳。     

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...