伪装涂层附着力影响因素研究

测试了伪装网用伪装涂层的剥离强度,提出了一种考核伪装涂层附着力的方法。研究了涂层附着力的来源,涂层与底材之间相互作用的机理,介绍了常用的涂层附着力改进剂,阐述了它们改善涂层附着力的作用机理,合理使用涂层附着力改进剂可以显著提高涂层的附着力。     

PVD涂层刀具及其寿命研究进展

结合PVD涂层刀具的发展现状,从单层涂层(二元氮化物涂层、多元氮化物涂层、碳化物涂层、氧化物涂层)、多层涂层等类别出发,分别介绍了5类PVD涂层刀具及其寿命的研究现状,并对PVD涂层刀具发展方向进行了探讨,展望了涂层向着多元化、复合化、超高硬度、摩擦系数低的发展趋势。     

边界润滑摩擦面固体润滑涂层技术发展的若干趋势

随着表面工程与涂层技术的发展,固体润滑涂层在机械零件上得到了广泛的应用,涂层材料与涂层工艺取得了很大的进展。本文论述了边界润滑摩擦面固体润滑涂层技术发展的若干趋势,指出开发新的涂层材料、涂层结构、涂层工艺,实现固/液混合润滑,以及利用涂层激光纹理技术提高润滑效果是固体润滑涂层技术发展的重要方向。     

不锈钢表面阻氚渗透涂层研究现状及进展

阻氚渗透是聚变堆设计中一项关键技术,综述了不锈钢表面氧化物涂层、铝化物涂层、钛基陶瓷涂层、硅化物涂层等阻挡氚渗透陶瓷涂层的研究现状,比较了铝化物涂层几种制备方法的特点,概述了陶瓷涂层的阻氚机理,并对阻氚涂层未来的研究重点进行了展望.     

表面处理复合涂层的摩擦学评价方法

从涂层的摩擦学评价的重要参数、涂层与基体间的粘合力、涂层力学性能、涂层的摩擦学特性以及涂层零件的摩擦学特性等方面介绍了金属切削刀具和模具等工件的复合涂层的摩擦学涂层的评价方法,指出了在轻合金涂层材料、低摩擦因数的涂层、涂层韧性的改进、涂层磨损试验方法、涂层设计和评价的工具等方面需要进一步研究。     

等离子喷涂纳米Al_2O_3-13%TiO_2陶瓷涂层的组织结构与抗冲蚀性能

采用等离子喷涂方法分别制备了常规和纳米Al2O3-13%TiO2陶瓷涂层,用扫描电子显微镜分析了涂层的显微结构,并对涂层进行了抗冲蚀试验。结果表明:常规陶瓷涂层具有典型的片层状结构,但纳米陶瓷涂层片层状结构并不十分明显,且涂层裂纹数量明显减少;纳米陶瓷涂层中的显微结构的变化改善了涂层的韧性和结合性能;在冲蚀过程中,常规陶瓷涂层表面剥落严重,而纳米陶瓷涂层的冲蚀质量损失较小,抗冲蚀性能比常规陶瓷涂层提高了30%左右。     

新型阻氢涂层的研究

介绍了阻氢涂层特别是新型阻氢涂层的研究进展,讨论了传统非氧化物和氧化物等常用涂层的优缺点。从新材料应用层面阐述了目前新型阻氢涂层的开发现状,论述了新材料的特点和阻氢性能的优点。传统涂层通过复合设计等手段着力解决涂层与基体的结合问题,减少服役期间裂纹和缺陷的产生,提升涂层综合性能。石墨烯和MXnen等二维纳米材料的应用从物理阻隔方面提供了氢气阻隔新方向,而金属玻璃薄膜为减少氢气扩散通道带来了新的思路。复合涂层依然是未来发展的主要方向,优化涂层结构设计、改善涂层界面将成为提高涂层质量的重要手段。     

智能变色涂层综述

随着国内外对变色涂层技术的深入研究,智能变色涂层的种类和技术不断进步并且智能涂层的市场潜力与需求也日益增大,在航空航天、建筑、家电中都能经常见到它们的身影。主要论述了智能变色涂层中光致变色涂层、热致变色涂层和电致变色涂层,阐述了它们的发展现状、应用前景以及存在的问题,并且扩展了一些其他的变色涂层,最后对智能变色涂层的发展做出总结。     

基于热四极法的涂层刀具切削温度分布研究

为研究涂层在切削过程中对刀具温度分布的影响,建立了涂层刀具的三维瞬态热传导分析模型,发展了基于热四极法的切削过程涂层刀具三维温度场求解算法,得到了涂层刀具的瞬态温度分布。研究了涂层厚度、热对流以及界面热阻对涂层刀具切削温度分布的影响,为切削加工中涂层厚度的确定、切削液的选择以及涂层刀具的失效诊断提供了理论依据。     

离子镀TiCN和TiN工具涂层的微结构与切削性能

采用电弧离子镀技术在硬质合金铣刀和钻头上镀覆了TiCN和TiN涂层,研究并比较了两种涂层的微结构与力学性能,以及涂层铣刀的高速切削性能和涂层钻头的切削性能。结果表明,TiCN和TiN涂层同为单相的Na-Cl型结构,并都呈现(111)择优取向的柱状晶,TiCN涂层的硬度为34.6GPa,远高于TiN涂层25.1GPa的硬度。在高速铣削条件下,TiCN涂层铣刀的后刀面磨损速率仅为TiN涂层铣刀的约三分之一。TiCN涂层钻头在钻孔数为TiN涂层钻头两倍时的磨损量仍低于TiN涂层钻头。TiCN涂层的高硬度及在较高切削线速度下的减摩作用是这种涂层刀具寿命提高的重要原因。     

Mice embryology: A microscopic overview

In this work, we studied the embryology of mice of 12, 14, and 18 days of gestation by gross observation, light microscopy, and scanning electron microscopy. Grossly, the embryos of 12 days were observed in C‐shaped region of the brain, eye pigmentation of the retina, first, second, and third pharyngeal arches gill pit nasal region on the fourth ventricle brain, cervical curvature, heart, liver, limb bud thoracic, spinal cord, tail, umbilical cord, and place of the mesonephric ridge. Microscopically, the liver, cardiovascular system and spinal cord were observed. In the embryo of 14 days, we observed structures that make up the liver and heart. At 18 days of gestation fetuses, it was noted the presence of eyes, mouth, and nose in the cephalic region, chest and pelvic region with the presence of well‐developed limbs, umbilical cord, and placenta. Scanning electron microscopy in 18 days of gestation fetuses evidenced head, eyes closed eyelids, nose, vibrissae, forelimb, heart, lung, kidney, liver, small bowel, diaphragm, and part of the spine. The results obtained in this work describe the internal and external morphology of mice, provided by an integration of techniques and review of the morphological knowledge of the embryonic development of this species, as this animal is of great importance to scientific studies. Microsc. Res. Tech. 2012. © 2012 Wiley Periodicals, Inc.     

带螺旋槽和双向微通槽动静压气体轴承静态特性研究

以具有螺旋槽和双向微通槽结构的动静压气体轴承为研究对象,用ANSYS中的Fluent对轴承静态特性进行仿真分析,通过改变螺旋槽和双向微通槽的宽度、深度,研究气膜厚度、主轴转速、偏心率、供气压力等参数对轴承静态特性的影响.结果表明:相对于单向微通槽(轴向微通槽和周向微通槽)结构,采用双向微通槽结构的轴承的承载力和刚度最优...     

振动子结构综合与修正方法研究综述

在大型复杂的结构设计过程中,子结构综合与修正方法由于其快速、动态、综合等特点越来越广泛地应用于现代结构设计之中,以完善子结构综合与修正方法知识参考、引起国内学者关注该技术研究为目的,阐述了振动子结构与系统之间的综合与修正方法。在子结构综合方法中,主要对比分析了模态缩减与综合、频域JETMUNDSEN、REN、机械阻抗导纳法综合法、频响函数奇异值分解降噪法、子系统转角自由度刚柔等效及转换方法的原理及应用,评述了上述方法的优点与不足,就尚未解决的问题作了进一步探讨;在子结构修正方法中,对比分析了多重参考基准修正法、目标函数动态修正法、参数型修正、神经网络型修正、灵敏度修正、频响函数修正等方法的应用,总结了模型修正方法中存在的一些问题。最后,提出了振动子结构综合及修正方法的研究趋势。     

Analytical dynamics of mechanisms—a computer oriented overview

General-purpose computer programs such as IMP, DRAM, MEDUSA and DYMAC, for the solution of inertia-variant (linkage-type) mechanisms are beginning to emerge. These programs, which automatically generate, and numerically integrate, the equations of motions, are based upon different but related analytical and numerical principles. There has also been much recent discussion of “influence coefficient” methods, energy methods and related matters. This paper reviews the various principles and techniques available for formulating the equations of motion, for integrating them numerically, and for solving the associated kinetostatic problem for the determination of bearing reactions. The relative advantages of vector methods, d'Alembert's Principle, Lagrange's Equations with and without multipliers, Hamilton's Equations, Virtual work, and energy methods are discussed. Particular emphasis is placed on how well-suited the various methods are to the automatic generation of the equations of motion, and to the form and order of the systems of differential equations they lead to. It is shown how velocity ratios, influence coefficients, centripetal coefficients, generalized inertia coefficients, and Christoffel symbols interrelate the various methods, and tie them to classical results of Analytical Dynamics such as the “explicit” equations of motion and the power-balance principle. Methods for solving both the general dynamics problem, and the kinetostatic problem, are reviewed, and the particular methods of implementation used in the recently developed general-purpose computer programs, and in other recent literature, are described.     

中等半径比内轴高旋圆柱间湍流场的大涡模拟

利用大涡模拟对中等半径比内轴高旋圆柱间湍流场进行了数值模拟。半径比为0.83,形状比为6,侧墙为静止侧墙、旋转侧墙及无剪切力侧墙3种边界条件。模拟结果表明,大涡模拟对该类问题有较强的预报能力。侧墙静止时,涡流始于靠近侧墙的左下方和右下方位置,然后涡心向上向中间移动,涡胞逐渐变大,外轴上形成众多小涡,小涡的涡心向下移动涡胞变大,最后涡胞混合在一起,充满整个轴间。侧墙旋转时,涡流始于靠近侧墙的左上方和右上方位置,然后涡心向上向中间移动,涡胞逐渐变大,外轴上形成众多小涡,小涡的涡心向下移动涡胞变大,最后涡胞混合在一起,充满整个轴间。在无剪切力侧墙边界条件,涡流场形成过程与侧墙旋转时形成过程相似。轴间流场最终形成固定数量的涡胞,且随着时间的推移,各个涡胞呈现此消彼长的局面,始终保持固定数涡胞的存在。在侧墙静止和无剪切力条件,流场最终形成8个涡胞;侧墙旋转时,流场最终形成6个涡胞。     

Study on the applicability of four flumes in small rectangular channels

Different experiments and numerical simulation research were carried out in order to explore the hydraulic characteristics and applicability of the cutthroat flume, NACA airfoil-shaped flume, airfoil pillar-shaped flume, and optimized airfoil-shaped flume in rectangular channels. The four flumes with contraction ratios of 0.4, 0.5, and 0.6 in rectangular channels were tested under 144 free-flow conditions. Based on the Fluent software, standard k-ε three-dimensional turbulence model and volume of fluid (VOF) method were utilized for numerical simulation in each working condition. The principle of critical flow was used to analyze the correlation between the discharge, the contraction ratio, and the upstream water depth. This correlation was used to obtain the discharge calculation formulas of the cutthroat flume, NACA airfoil-shaped flume, airfoil pillar-shaped flume, and optimized airfoil-shaped flume in rectangular channels. The Froude number in front of the flume, the backwater height, the critical submergence degree, the velocity distribution, the head loss, the discharge measurement formula, and the accuracy were studied and compared. It can be concluded from the results that the cutthroat flume, NACA airfoil-shaped flume, airfoil pillar-shaped flume, and optimized airfoil-shaped flume all have good applicability in rectangular channels. Moreover, the hydraulic characteristics of all the four flumes meet the water measurement specifications in the irrigation area. The upstream Froude number of the NACA airfoil-shaped flume is the smallest, whereas the backwater height and head loss of the cutthroat flume and optimized airfoil-shaped flume are the smallest. It is also worth noting that the critical submergence degree of the optimized airfoil-shaped flume is the highest, with an average value of 0.85. The discharge measurement formulas of the four flumes have been deduced using the correlation between the discharge, the contraction ratio, and the upstream water depth. It was found that the average errors between the calculated discharge and the measured discharge of the four flumes are 3.17%, 2.17%, 1.53%, and 2.29%, respectively, which are less than 5%, and therefore meet the discharge measurement requirements. In the agricultural irrigation system and flow monitoring system, the hydraulic characteristics of the four flumes can provide a reference and basis for the selection of flumes in the rectangular channel.     

大型钢厂钢渣运输专用设备SPC90的研制开发

SPC90抱罐车的最大额定载重为90t,是钢渣处理生产线上的关键设备,抱罐车的驱动、转向、制动和工作装置等操作均采用电液比例控制,驱动采用液力传动,通过动力换档电液控制系统和三相变矩器的结合,解决了抱罐车行走过程中负载变化频繁和发动机匹配等问题;转向系统为电液动力转向,制动系统采用基于湿式盘式制动,工作装置采用闭芯式负荷传感电液控制系统,开发了基于CAN总线的电气控制系统,抱罐车还具有遥控、防撞和故障诊断等智能化系统。     

可重复展收单折伞状天线机构创新设计与实验验证

针对现有单折伞状天线无法实现自动重复展收的问题,创新性地提出一种滚动轴承结合销轴、丝杠结合推板的展收机构,并进行了原理样机设计与验证。所提展收机构由单折肋、中心座、丝杠、丝杠螺母、上下推板、挡板、滚动轴承、销轴等组成。通过电机带动丝杠往复运动,推板上下移动,辐射肋根部在上下推板间滚动,辐射肋绕销轴转动,挡板限位锁定的方式,弥补了现有单折伞状天线的不足,创新性地实现了单折伞状天线辐射肋的重复展开与收拢。对辐射肋进行了运动学分析,得出了角度、角速度以及角加速度之间的转换关系。同时对反射体中的关键零部件进行了力学校验,以确保其可行性。设计并制作了4 m口径可重复展收单折伞状天线原理样机。通过原理样机重复展收试验,验证了所提创新机构的有效性。     

聚焦型微通道内气泡生成特性数值模拟

微气泡因具有比表面积小和稳定性好等特点被广泛应用于污水处理和矿物浮选等领域。为了高效获得稳定的微气泡,利用COMSOL软件研究了聚焦型微通道中气、液相流速、表面张力、液相黏度和壁面润湿性对气泡生成的影响。结果表明：当气相流速增加时,气相克服表面张力的能力增强,气泡的脱离尺寸和频率增大,脱离时间减小;液相流速增加时作用在微气泡上的惯性力和剪切力增大,气泡脱离时间和脱离尺寸均减小;表面张力增大时气泡脱离时间和脱离尺寸增大,脱离频率减小;液相黏度增大时,作用于气泡的黏性力随之增大,气泡的脱离时间和脱离直径均随之减小,脱离频率增大;接触角从40°增大到180°,气泡的脱离尺寸和脱离时间整体先增大后减小,脱离频率先减小后增大。     

生产进度跟单员应具备的能力综述

跟单员是客户与公司、公司与生产、生产与客户这个循环关系的连线人,其工作质量的好坏直接影响公司的服务品质和企业形象。在生产性跟单中,原料的采购、工艺流程与技术、生产进度与质量监控、投入与产出,由于企业性质不同,跟单内容和流程也相应变动,各自有所侧重。在小型企业中,生产跟单员身兼数职,既是内勤员,又是生产计划员、协调员、物控员,还可能是采购员。在中型、大型企业,则代表企业的业务部门向生产制造部门催单要货,跟进生产的异常,跟踪出货。根据跟单的对象和核心事物的不同,可分为生产跟单和外贸跟单。本文主要讨论中、大型企业的生产跟单。根据业务进程,此类跟单可以分为前程跟单、中程跟单和全程跟单,本文主要探讨前程跟单中的生产进度跟进。生产进度跟单的基本要求是使生产部门能按订单及时交货,使生产进度与订单交货期相吻合,尽量做到不提前交货,也不延迟交货。