高镍三元正极材料LiNi0.8Co0.1Mn0.1O2的合成与电化学性能研究

采用高温固相法在不同条件下合成了一系列球形LiNi0.8Co0.1Mn0.1O2正极材料,并通过XRD、SEM、TEM、EDS等表征手段对其物相结构、形貌以及电化学性能进行了研究.结果表明,Li/Me(摩尔比)为1.07时合成的正极材料结晶良好,结构稳定,以0.2 C倍率在2.8～4.3 V电压范围内的首次放电比容量为200.4 mAh/g,首次充放电效率为86.7％,1 C放电比容量为189.5 mAh/g,50次循环之后的放电比容量为178.3 mAh/g,此时容量保持率高达94.1％.继续循环至100次比容量还有145.7 mAh/g,容量保持率为76.9％.     

多轴运动控制技术在智能轮椅的应用和发展前景

介绍了一种自主研发的多功能智能轮椅的技术实现和应用.系统采用步进电机和24 V直流电机的解决方案,由自主研发的控制板,配合驱动控制单元,实现轮椅多个自由度的运动控制,具有响应迅速、定位精准的特点,其功能较好地满足了健康养老市场的需求.     

铝合金MIG焊丝伸出长度视觉提取算法及动态过程辨识

建立了一种基于视觉传感的铝合金MIG焊丝伸出长度检测系统,并提出了相应的图像处理算法,通过使用CCD摄像机,实时获取焊接区图像,根据焊丝特征定位其在图像中的纵坐标,然后对图像进行剪切,移位并叠加,使焊丝特征与背景之间的差别得到强化并提取焊丝伸出长度信息,结果表明,该算法快速有效.在以上工作的基础上,设计了阶跃响应试验,对焊丝伸出长度受送丝速度的影响规律进行了辩识,得到了数学模型,为铝合金MIG焊接过程中焊丝伸出长度传感与控制奠定了基础.     

The characterization and corrosion resistance of cerium chemical conversion coatings for 304 stainless steel

A golden yellow-colored cerium conversion coating was obtained on 304 stainless steel surface by immersing the steel into a solution containing cerium (III), KMnO₄ and sulfuric acid. The corrosion resistance of the coatings was evaluated by electrochemical methods, potentiodynamic polarization experiments and electrochemical impedance spectrum. The experimental results indicated that the corrosion resistance for the conversion coated 304SS in 3.5% NaCl solution increased markedly. The corrosion potential of the treated steel increased to a more noble level, the pitting corrosion potential increased also, the passive potential range was enlarged markedly and the passive current density decreased about one order compared to that of the untreated steel. The cathodic and anodic reaction were both inhibited to some extent. The chemical state of the elements in the coatings was investigated by XPS. The cerium element was in the form of tetravalent state. And AES depth profile analysis suggested that the thickness of the conversion coatings was less than 66 nm. The mechanisms of coatings formation and corrosion resistance are discussed.     

钛金属与汽车工业研讨会纪要

综述了介孔材料的合成方法、分类、形成机理、形貌控制和应用。目前各种形状如球形、棒状、片状、螺旋形和绳形等形状的介孔材料已经采用溶胶．凝胶、自组装、微乳、反胶束和超声等方法合成出来。按化学组成介孔材料分为硅基和非硅介孔材料，硅基介孔材料已被很好地研究，相反，非硅介孔材料虽然有着广泛的应用前景但研究不多。介孔材料的几种形成机理已经被提出，主要包括液晶模板和协同组装机理。作者也采用化学超声和反胶束方法制备出新奇的介孔二氧化钛粉末和薄膜材料，其光催化活性明显高于普通二氧化钛粉末和薄膜材料。     

45钢的离子氮碳共渗-离子渗氧复合处理

研究了45钢离子氮碳共渗-离子渗氧复合处理工艺。试验表明，45钢经离子氮碳共渗-离子渗氧复合处理后，表层可获得化合物和氧化物的复合层，该复合处理可以明显提高45钢的耐磨性。     

Design of a six-axis high precision machine tool and its application in machining aspherical optical mirrors

The paper presents the design of a six-axis machining system and its application in fabricating large off-axis aspherical mirrors with sub-aperture lapping techniques. The new system is based on computer-controlled optical surfacing (CCOS), which combines the faculties of grinding, polishing, and on-machine profile measuring, has the features of conventional loose abrasive machining with the characteristics of a tool having multiple degrees of freedom moving in planar model. And a novel dual touch-trigger probe profiler is designed, which is composed of a probe, model METRO-MT60 made by HEIDENHAIN Co., is integrated into the system for measuring the shape accuracy of the tested aspherical surface, another probe modeled METRO-MT12 is designed as a calibrating device for minimizing the cosine error caused by assembly inaccuracy. The new CNC machining system with two kinds of moving coordinate systems, dual tool activities and on-machine measuring is presently developed based on the new concept. The general material removal function during machining is analyzed on the basis of the Preston hypothesis. Further, an alignment test of the measuring profiler is carried out using a leveling rule as a specimen. The accuracy of the optical surfaces measured by the dual probe profiler is found to be within 1 μm PV after removing cosine error and error compensating, achieves to the resolving power of the profiler is about 0.2–0.5 μm, so the developed system can be applied to the shape accuracy measuring of aspheric fabrication with micro precision during fine grinding process according to the calibrating results. Finally, the manufacturing experiments are carried out by virtue of an off-axis oblate ellipsoid mirror with rectangular aperture as 770 mm×210 mm and centered 127 mm. The accuracy of the aspherical mirror improved from the initial form error of 17.648 μm rms to the final one of 0.728 μm rms after grinding for 200 h.     

Effect of tribological media on tribological properties of multilayer Cr(N)/C(DLC) coatings

In this research, Cr(N)/C(DLC) multilayered coatings were deposited on M2 steel substrates by an unbalanced magnetron sputtering technique. By varying the substrate rotation speed, four multilayered coatings with different bilayer thickness were produced. The bilayer thickness and structure of multilayered coatings were characterized by low-angle XRD, XPS depth profile, and cross-section TEM observation. The tribological investigation focused on the effect of layer thickness and tribological media on tribological property of the multilayer coatings against Al counterface. A pin-on-disc tribometer with a tribological medium container was used to investigate the wear behaviours of the four multilayered coatings under dry and wet (distilled water and S500 coolant) sliding. A stylus surface profilometer was used to measure wear rate. The investigation of wear tracks and wear mechanism was performed using Scanning Electron Microscopy (SEM). The research results showed that coatings with different bilayer period performed different tribological behaviour. The proper tribological media applied in the wear tests could improve the wear properties of multilayer coatings.     

Zr-Si-N扩散阻挡层及其热稳定性的研究

用反应磁控溅射法在不同偏压下沉积了Zr-Si-N扩散阻挡层,结果表明:Zr-Si-N膜的Si含量、电阻率随偏压的升高而降低;Zr-Si-N膜的晶体相随溅射偏压的升高而增加;Zr-Si-N扩散阻挡层的热稳定性高,在850℃时仍能有效阻挡Cu的扩散.     

硝硫混酸与Ag、Cu反应的动力学

用失重法探讨了硝硫混酸此例、浸出温度和时间等因素对银的溶解和铜的钝化的影响。结果表明:在一定的[HNO_3]范周内,较高温度时,银的溶解符合一级反应规律;求得银的溶解量与时间、HNO_3起始浓度等的关系式和相应的反应活化能;铜在此条件时是钝化的。本实验再一次证实了银的溶解和铜的钝化机理的正确性,也为银、铜的分离提供了实验依据。