基于机器视觉的零部件表面缺陷检测方法研究

针对零部件表面缺陷检测精度问题,提出一种基于机器视觉的零部件表面缺陷检测方法。传统的利用机器视觉对零部件表面缺陷检测方法中,由于零部件表面的光学反射特性,因此无法对零部件表面缺陷进行高精度的检测。提出的基于机器视觉的零部件表面缺陷检测方法引进了差影法检测模型,根据部件表面特征,利用分段线性灰度算法对部件表面细小的缺陷进行区域检测,并且结合了灰度共生矩阵的换算熵作为判定的依据,最终建立的缺陷检测模型是利用矩阵方位度和相似度之比进行高精度的检测。为了验证设计的基于机器视觉的零部件表面缺陷检测方法的有效性,通过仿真试验证明了该设计方法,结果表明该方法能够有效地解决零部件表面缺陷检测的精度问题。     

超声扫描检测的应用工艺研究

通过对几种常见的检测模式及缺陷分析方法进行介绍,并对几种常见器件进行检测、分析,总结出一套针对半导体器件及封装领域常见缺陷的检测方法,给出了具体的缺陷分析理论,为利用超声手段对器件进行无损检测和质量控制提供了重要参考。     

带涂层金属板件缺陷的激光超声检测研究

针对带涂层金属板件的缺陷检测存在分辨率低,形状、尺寸难确定等问题,基于热弹激励原理、依托两套不同的检测系统对带涂层金属板件的缺陷进行检测,展开对激光超声检测技术的方法研究。首先通过实验验证这项技术的可行性和有效性、检验涂层对缺陷检验有无影响,其次利用实验产生的数据以及图像分析了涂层影响下缺陷波形并对缺陷波进行理论分析,然后对波形参数进行了实时计算最终得到了50 μm涂层影响下缺陷的形状和尺寸特征 。研究结果表明:激光超声检测技术可以实现对带涂层机械板件缺陷的定性定量检测,可应用于工程领域的实时在线检测,并有良好的发展前景。     

激光扫描热成像无损检测关键参数影响分析

对一种新型红外热波无损检测技术激光扫描热成像无损检测技术进行了研究。在深入分析检测机理的基础上建立了激光扫描热成像有限元数值计算模型,选取缺陷处和非缺陷处表面最大温差作为特征量,对样品材料、缺陷大小、缺陷深度、激光扫描速度和激光扫描功率等关键参数对激光扫描热成像检测的影响规律进行了仿真和分析,为该新技术的进一步发展和应用提供了参考;采用数据拟合方法得出了各参数和表面最大温差关系,并以此为基础提出了激光扫描热成像技术检测参数控制策略,实际检测过程中,可据此针对样品缺陷特征快速准确设置检测参数,提高检测能力。     

基于模糊C均值聚类和Canny算子的红外图像边缘识别与缺陷定量检测

针对脉冲红外热成像检测缺陷构件时,红外图像噪声较大、边缘信息模糊等特点,提出了一种基于模糊C均值聚类和Canny算子相结合的边缘检测新方法。该方法首先对输入的红外图像进行整体灰度变换,采用模糊C均值聚类对图像进行区域分割、提取和二值化;再将各个区域进行叠加,使红外图像的边缘变得连续;最后,采用Canny算子对处理后的图像进行边缘检测,实现缺陷的识别。在图像边缘检测基础上,分析了图像定位缺陷位置与实际缺陷位置之间的相对误差,并运用物像关系,实现缺陷几何尺寸的定量检测。结果表明:该方法对缺陷边缘识别完整清晰,具有较高的定位精度和抗噪能力,有利于缺陷的识别与定量检测。     

油气管道缺陷检测技术综述

油气管道泄漏将会造成巨大的经济损失和环境污染,因此,需要采用管道缺陷检测相关技术来定期对管道进行缺陷检测,最终达到对油气管道的保修和维护目的.本文首先归纳了油气管道缺陷检测技术演进过程,然后从申请人和申请量的角度进行了专利分析.     

电子元器件缺陷检测技术研究与开发

目前,电子元器件缺陷的检测大多都是对其内部和外部进行检测,内部检测难度比较大,检测参数和检测过程较为复杂、麻烦,而且内部的参数有时候后不能准确地进行检测;而外观缺陷检测大多数只通过人眼或显微镜进行人工观察,效率低下,浪费人力物力;为此通过对电子元器件的内部和外部缺陷进行检测判断是否存在性能参数失效,以及利用数字图像处理技术对电子元器件外观缺陷进行检测和分析。具体地,明确内部参数检测原理和外部检测主要结构与功能,外部检测主要获取图像进行分析,同时,执行图像分割与降噪处理,借助于生成的灰度共生矩阵将纹理特征值计算出来,与预存储缺陷数据进行比对,明确元器件的外部具体缺陷情况。     

基于主动式全景视觉的管道形貌缺陷检测系统

针对现有的管道缺陷检测技术不能同时对管道的形、貌缺陷进行检测与评估这一工程难题,在前期研究工作的基础上,设计了一种基于主动式全景视觉的管道内部缺陷检测系统,能够快速获取管壁密集点云的三维坐标,同时对内壁表面缺陷进行检测与评估。首先利用主动式全景视觉传感器（AODVS）实时获取内壁全景图像和激光横断面扫描全景图像,然后对管道内壁全景图像进行柱状展开、预处理和缺陷检测及分类等处理;然后对激光横断面扫描全景图像处理,计算管道内壁点云的三维坐标,进一步对管道缺陷部分进行定量分析,最后利用三维建模技术重构带有真实纹理信息的管道模型。实验结果表明:文中设计的检测系统能够对管道凹凸形变、孔洞、管壁裂缝、腐蚀等缺陷进行检测与分析,具有较高的检测精度,为管道内表面三维测量和重构提供了一种新的手段。     

BGA封装器件焊点缺陷X-射线检测法

讨论了BGA器件焊接的特点,并对BGA器件焊接过程中产生的缺陷进行了阐述,采用X-射线检测仪检测了BGA封装器件安装焊点的几种常见缺陷,分析、阐述了其图像与相应缺陷的关系,结果表明X-射线检测方法能够准确地检测出BGA封装器件安装中的各种焊点缺陷,并能够自动计算BGA封装器件安装焊点的空洞率,对空洞缺陷的快速检测和预防具有实际意义.     

基于超声相控阵的轮辋探伤实证分析

基于相控阵超声探伤技术,采用直射声束法对轮辋轴向缺陷试块中横孔的径向深度和轴向深度进行了检测,精确定位了横孔的位置,并通过AVG曲线法对缺陷的尺寸进行了定量评定和分析。实验结果表明,缺陷较浅则检测的误差波动较小、干扰波较少;缺陷较深则可能出现轮廓回波等非缺陷波,对缺陷回波的分析有较大影响;远场区的缺陷可以通过AVG曲线进行精确评定。     

Generation of Amphiphilic Janus Bubbles and Their Behavior at an Air–Water Interface

This paper presents the generation of amphiphilic Janus bubbles and their behavior at an air–water interface. Janus bubbles are generated by selectively depositing gold onto one side of dried nanoparticle‐shelled bubbles. To generate nanoparticle‐shelled bubbles that can withstand drying without significant changes in their structure, it is critical to control the ratio of bubble radius to shell thickness using a microfluidic technique. It is observed that the behavior of Janus bubbles at an air–water interface is very different from that of unmodified nanoparticle‐shelled bubbles. Interfacial assembly of amphiphilic Janus bubbles shows that they interact with one another via long‐ranged attractions. The origin of this long‐ranged attraction is quadrupolar capillary interactions due to the undulation of the three‐phase contact line around the Janus boundary. The interparticle forces between interface‐trapped Janus bubbles are determined using a particle tracking method. The shape of the deformed air–water interface around Janus bubbles is directly observed as well as the orientation of Janus bubbles using a gel‐trapping technique. These observations verify that the air–water interface is pinned around the boundary between the two hemispheres and that the chemical heterogeneity of this boundary leads to irregular contact line around Janus bubbles.     

电解质溶液复介电常数测量中气泡影响的分析

电解质溶液复介电常数的准确测量对于生物电磁学和微波化学等领域是至关重要的,简单而有效的测量方法就是使用开口同轴线。由于电化学反应,插入溶液的测量探头表面容易产生气泡,对测量结果产生影响。文中针对气泡的不同位置和大小对氯化钠溶液复介电常数测量的影响进行了数值分析,计算结果表明,电解质溶液复介电常数测量值的实部受气泡影响很小,而虚部受气泡的位置、大小和个数的影响。     

In‐Air Bubble Phobicity and Bubble Philicity Depending on the Interfacial Air Cushion: Toward Bubbles Manipulation Using Superhydrophilic Substrates

Bubbles, a typical air‐in‐liquid system including both underwater and in‐air bubbles, are important phenomena involved in our daily life and engineering fields. So far, the fundamental and dynamics for in‐air bubbles largely remain unclear. Here, two typical in‐air wetting states of the bubble are revealed: the bubble‐phobic state in which a bubble with a perfect spherical shape stays on the liquid surface but without coalescence with the liquid; and the bubble‐philic state in which a bubble on the liquid substrate gives a quasi‐hemispherical shape. It is proposed that the bubble phobicity is a typical high‐energy state where the air cushion at the bubble/liquid interface plays a crucial role in preventing their coalescence by generating an energy barrier. By applying an external force to overcome the energy barrier, the bubble will distort and finally be stabilized in a bubble‐philic state. It is demonstrated that superhydrophilic substrates enable manipulating bubbles in air: a superhydrophilic surface with microscale hairy textures shows robust in‐air repellence to the bubbles, while a hemispherical bubble is capable of transport directionally in air on a superhydrophilic conical fiber. Here, the concept of superwetting into air‐in‐air system (liquid films) is promoted, which may open a new perspective in surface and interface chemistry.     

Magnetocontrollable Droplet and Bubble Manipulation on a Stable Amphibious Slippery Gel Surface

Smart manipulation of liquid/bubble transport has garnered widespread attention due to its potential applications in many fields. Designing a responsive surface has emerged as an effective strategy for achieving controllable transport of liquids/bubbles. However, it is still challenging to fabricate stable amphibious responsive surfaces that can be used for the smart manipulation of liquid in air and bubbles underwater. Here, amphibious slippery surfaces are fabricated using magnetically responsive soft poly(dimethylsiloxane) doped with iron powder and silicone oil. The slippery gel surface retains its magnetic responsiveness and demonstrates strong affinity for bubbles underwater but shows small and switching resistance forces with the water droplets in air and bubbles underwater, which is the key factor for achieving the controllable transport of liquids/bubbles. On the slippery gel surface, the sliding behaviors of water droplets and bubbles can be reversibly controlled by alternately applying/removing an external magnetic field. Notably, compared with slippery liquid‐infused porous surfaces, the slippery gel surface demonstrates outstanding stability, whether in air or underwater, even after 100 cycles of alternately applying/removing the magnetic field. This surface shows potential applications in gas/liquid microreactors, gas–liquid mixed fluid transportation, bubble/droplet manipulation, etc.     

基于涡流锁相热成像的刹车片内部气泡检测

刹车片是汽车必不可少的制动部件,其内部气泡严重影响行车安全。传统敲击听声检测方法主观性强,检测效率低,难以满足准确高效的检测需求。基于涡流锁相热成像具有非接触、大面积检测的特点,将其应用于少金属摩擦材料汽车刹车片的内部气泡检测。采用有限元仿真探索了刹车片结构和内部气泡对相位的影响,并以背钢处相位为参考,分离出气泡存在。对刹车片试样进行检测,并采用水切割观察剖面的方法验证结果。实验表明涡流锁相热成像检测方法能有效检测少金属摩擦材料汽车刹车片的内部气泡。     

舰船尾流气泡激光回波偏振压缩探测技术研究

对舰船尾流气泡探测是对舰船进行跟踪的一种独特的方法,采用蓝绿激光对尾流气泡 探测是可行的。在分析蓝绿激光在海水介质中的衰减特性基础上,提出采用偏振压缩技术对大动态范围的激光回波信号进行压缩,提高对尾流气泡探测的精度和深度。     

Stable Omniphobic Anisotropic Covalently Grafted Slippery Surfaces for Directional Transportation of Drops and Bubbles

Directional transportation and collection of liquids and bubbles are highly desirable in human life and industrial production. As one of the most promising types of functional surfaces, the reported anisotropic slippery liquid‐infused porous surfaces (SLIPSs) demonstrate unique advantages in liquid directional transportation. However, anisotropic SLIPSs readily suffer from the depletion of lubricant when used to manipulate droplets and bubbles, which leads to unstable surface properties. Therefore, fabricating stable anisotropic slippery surfaces for the directional transportation of drops and bubbles remains a challenge. Here, stable anisotropic covalently grafted slippery surfaces are fabricated by grafting polydimethylsiloxane molecular brushes onto directional microgrooved surfaces. The fabricated surfaces show remarkable anisotropic omniphobic sliding behaviors towards droplets with different surface tensions ranging from 72.8 to 37.7 mN m^?1 in air and towards bubbles underwater. Impressively, the surface maintains outstanding stability for the transportation of droplets (in air) and air bubbles (underwater) even after 240 d. Furthermore, anisotropic self‐cleaning towards various dust particles in air and directional bubble collection underwater are achieved on this surface. This stable anisotropic slippery surface has great potential for applications in the directional transportation of liquids and bubbles, microfluidic devices, directional drag reduction, directional antifouling, and beyond.     

水中气泡光学特性的蒙特卡罗模拟

基于Mie散射理论的单个气泡光散射,考虑光的多次散射,用蒙特卡罗方法模拟计算水中气泡群的光散射特性.计算结果表明：光的后向散射随气泡数密度的增加而明显增强,并且在折射率较大的海水中这种增强会更加明显,从而说明利用尾流中气泡群的光散射特性研究光自导鱼雷是可行的.     

Bubble Architectures for Locally Resonant Acoustic Metamaterials

Soft acoustic metamaterials that embed soft materials in a host media have promising applications in aqueous environments. However, the preparation of soft metamaterials under water and realization of low‐frequency soft acoustic metamaterials remains a challenge. By combining 3D printing technology and surface hydrophobic properties, this work presents a general approach to construct 3D soft acoustic metamaterials using bubbles as resonator units. Low‐frequency broadband locally resonant metamaterials can be realized using patterned bubbles with bandgaps that are orders of magnitude wider than other locally resonant metamaterials. In addition, a water‐to‐air ultratransmission metasurface is prepared by patterning a layer of bubbles beneath the water surface, which allows for the ultratransmission of sound across an air–water interface. This strategy opens up promising avenues for many applications based on locally resonant metamaterials such as deep subwavelength acoustic superlenses or negative‐refraction metamaterials.     

辊压法制备柔性双稳态液晶显示器件

基于PET塑料薄膜取代硬质玻璃作为基板材料制备柔性液晶盒时,采用传统制备工艺会产生盒厚度不均以及盒中残留气泡等现象,导致柔性液晶器件性能变差。采用辊压工艺可以有效地解决上述问题,文章对其工艺流程进行了详细描述。实验发现,通过在辊压工艺中加热两片基板以降低溶液的黏度,能够有效地避免气泡残留,获得厚度均匀的柔性液晶盒。应用辊压工艺和聚合物分散胆甾相液晶,成功地制备了尺寸为7cm2的反射式柔性双稳态液晶盒。利用正交偏光显微镜观察了聚合物分散液晶的相形态,紫外分光光度计测试了其光电性能:最高反射率为22.8%,对比度为2.259,阈值电压为78V,饱和电压为99V。