熔石英表面损伤修复点上烧蚀碎片的分类与去除

熔石英光学元件表面损伤修复点周围的烧蚀碎片是诱导元件损伤的一个主要因素。根据烧蚀程度将修复点周围的烧蚀物质分为两类,然后针对不同类型的烧蚀采取大光斑CO2激光钝化和氢氟酸缓冲溶液刻蚀清洗两种方法对其进行去除处理,并且得到具体的优化处理参数。实验结果表明,两种方法都可以有效地去除修复点周围的烧蚀碎片,达到有效提升修复点抗激光损伤能力的目的。     

激光沉积修复GH4169合金试验研究

采用激光沉积修复技术对GH4169镍基高温合金贯通槽式损伤工件进行修复,分析了修复过程中气孔及熔合不良等缺陷的产生原因,通过优化工艺参数,获得了无缺陷的修复件;考察了修复件的微观组织及力学性能,并对修复件进行了局部热处理。结果表明:优化工艺参数后得到的修复区和基体形成了致密的冶金结合,采用局部热处理可明显提升修复件的抗拉强度。     

基于数学形态学的非规则缺失图像修复仿真

面对非规则缺失图像修复过程中容易出现的毛刺和小孔问题，在数学形态学支持下修复非规则缺失图像。结合数学形态学方法对修复图像膨胀和腐蚀预处理，避免修复区域受到干扰出现毛刺。预处理待修复图像后，获取待修复图像的全部像素点，连接像素点形成一个待修复轮廓，计算该部分的像素点优先权。通过粗略、精细搜索步骤定位最佳匹配块。在保证未知像素块相邻四个方向像素颜色一致的基础上填充像素。通过分割图像阈值，确定缺失区域基准点灰度值，判断目标点和噪声点，实现噪声点滤波处理，避免出现小孔问题。由实验结果可知，所提方法最高PSNR值为0.98，且无毛刺、无小孔，具有良好修复效果。     

不同脉宽皮秒激光对介质膜损伤修复的热影响

为了更深层次探究超短脉冲激光对惯性约束聚变(ICF)光学系统中常见的多膜层元件损伤修复性能以及特点,分别采用了240、35、6ps的1053nm激光脉冲在1053nm 0°高反膜上进行了损伤修复以及损伤增长测试实验,并在1053nm 45°高反膜上进行了大损伤区域的扫描修复实验。通过比较不同脉宽的修复点形貌以及损伤增长阈值,说明了超短脉冲用于修复多膜层光学元件损伤的优越性,并且脉宽越短修复效果越好。多点脉冲扫描修复结果表明,可以通过三维控制系统来任意控制扫描修复点形貌以达到最佳修复状态。     

基于Petri网的复杂可修复系统可靠性仿真研究

为了在复杂可修复系统的可靠性模型中引入修复过程,实现系统使用维修保障全过程仿真,使用Petri网建立了一种可修复系统的可靠性模型,通过模型内部token的移动控制系统组成单元的状态。以某型飞机为例进行了仿真。仿真结果表明,模型易于实现,具有较好的拓展性,可以有效地反映系统的修复过程,从而为系统的使用维修保障全过程仿真提供条件。     

影视作品霉斑数字化修复解析

《秋决》是台湾导演李行1 971年拍摄的影片,并于1 972年一举夺得第十届金马奖最佳剧情片、最佳导演、最佳男主角、最佳女配角和最佳彩色影片摄影五项大奖.时至今日这部优秀的影片留下了严重的岁月伤痕,胶片由于年代久远,保存环境不够理想造成影片损伤严重.该片于201 4年进行了数字化精致修复,在修复过程中霉斑的处理是整部影片修复的难点.该片的数字化霉斑修复经验,对其他电影档案影片类似问题的处理,有着重要的参考指导意义.本文以影片《秋决》为例,针对影视作品在数字化修复过程中的霉斑问题,提出了相应处理方案及修复流程,并针对修复过程中的注意事项,进行了修复前后效果展示.     

熔石英表面紫外损伤点的飞秒激光修复技术

熔石英表面激光损伤发展问题一直制约着高功率激光系统的运行通量,采用飞秒激光修复损伤点抑制损伤发展并探索修复机理。首先采用时域有限差分方法(FDTD)分析不同形状修复点的电场分布,优化修复点结构。通过改变飞秒激光脉冲能量、样品台移动参数控制修复点的形状、尺寸与深度,实现最优化修复结构。结果表明矩形修复结构降低了局部区域光强分布,经飞秒激光修复后,修复点的损伤发展阈值远高于修复前损伤点的发展阈值。采用微区电子能谱仪(EDS)分析修复点的化学成分发现飞秒修复能减少氧缺陷含量,从而降低吸收系数。因此,减少吸收性缺陷以及降低局部光强是抑制损伤发展的关键因素。     

基于改进深度卷积生成对抗网络的刺绣图像修复

目前中华传统刺绣工艺传承保护问题中的修复任务主要以人工为主，修复过程需要大量的人力、物力。随着深度学习的高速发展，不同类型的刺绣文物损伤可以利用生成对抗网络进行修复。针对上述问题，提出一种基于改进深度卷积生成对抗网络（DCGAN）的刺绣图像修复方法。首先，在生成器部分引入空洞卷积层扩大感受野，并添加卷积注意力机制模块，在通道与空间2个维度增强重要特征的指导作用；在判别器部分增加全连接层数提升网络解决非线性问题的能力；在损失函数部分联合均方误差损失与对抗损失通过网络训练相互博弈的过程实现刺绣图像修复。实验结果表明：引入空洞卷积层与注意力机制提升了网络性能与修复效果，最终得到修复图像的结构相似性高达0.955，能够得到较为自然的刺绣图像修复效果，可以为专家提供纹理、色彩等信息作为参考辅助后续的修复。     

基于地址分割的嵌入式存储器内建自修复方法

内建自修复技术是一种有效修复嵌入式存储器中失效单元的方法.在传统的内建自修复过程中,需要对故障地址进行多次的读写操作,功耗比较大.本文提出了一种基于地址分割的嵌入式存储器内建自修复方法.该方法将故障地址分割成两部分,对BIRA内部存储器的访问分两个步骤进行,有效简化了地址比较过程,降低了功耗.仿真试验表明,本文方法能够在实现存储器故障自修复同时显著降低修复与工作过程中产生的功耗.     

激光沉积修复BT20合金试验研究

采用激光沉积技术对BT20钛合金锻件加工超差及服役损伤进行修复,对修复过程中气孔和熔合不良等缺陷的形成进行了原因分析,并采用了优化工艺参数,对激光熔池施加超声外场等手段,获得无缺陷的修复试样。考察了试样的微观组织和主要合金元素的分布,测量了激光沉积层的显微硬度。结果表明:优化工艺参数后得到的修复组织和基体形成致密的冶金结合,而施加超声外场使修复区的气孔率明显下降;修复试样整体无合金元素的偏析,显微硬度分布从基材到修复区呈递增趋势。     

Study of the Formation of Bubbles in Rigid Substrate-Flexible Substrate Bonding Using Anisotropic Conductive Films and the Bubble Effects on Anisotropic Conductive Film Joint Reliability

The formation of process-related bubbles that become entrapped inside the anisotropic conductive film (ACF) layer during bonding processes remains an issue. The formation of these bubbles is strongly influenced by the process variables, such as bonding pressure and bonding temperature. Therefore, bonding process variables of bonding temperature, bonding pressure, and type of flexible substrate (FS) were changed in order to investigate the effects of the changes as they concern the formation of bubbles. According to the results, the tendency toward bubble formation was closely related to these three factors. The bubble area increased as the bonding temperature increased. Moreover, the shape and tendency of bubbles coincided with temperature distribution in␣the ACF layer. Two different types of FS, each with different surface roughnesses and energies, were used. The bubbles formed only on the FS with the larger roughness and lower surface energy. According to the results from a surface energy measurement of FS types using goniometry, a FS with a higher surface energy is favorable for a bubble-free assembly, as the higher surface energy provides better wettability. In addition, in order to investigate the effect of bubbles on the reliability of ACF joints, the pressure cooker test (PCT) was performed, and all samples with bubbles electrically failed after 72 h of a PCT, as the process-related bubbles provided a moisture penetration path and entrapment site for moisture. However, all type 1 test vehicles (TVs) survived even after 120 h of a PCT. Therefore, Ar and O₂ plasma treatments were performed on the FS with the lower surface energy in order to improve the surface energies and wettability. Following this, the bubbles were successfully removed at rigid substrate (RS)–FS bonding joints using ACFs.     

尾流气泡激光散射的测量

采用收发分置的光学结构实现了尾流气泡对532 nm激光在散射角5°～175°内的散射测量,同时测量了水的激光散射。散射角度的改变是通过发射系统不动而转动接收系统来实现的。解决了散射信号大动态范围的压缩问题,讨论了接收视场内散射体积随散射角的变化。分析了气泡散射的信号特征,并提出了气泡散射信号的功率谱密度处理法。将实验结果与米氏理论结果进行了对比,发现尾流气泡的激光散射强度及其随散射角的变化趋势与米氏理论结果吻合得很好,与水的散射相差近一个数量级。研究结果表明利用激光可以将气泡和水的散射区别开,即利用激光探测尾流气泡的存在具有可行性。     

Three-dimensional measurement of bubble volume based on dual perspective imaging

This paper presents a new three-dimensional (3D) volume measurement approach of bubble in gas-liquid two-phase flow. According to the dual perspective imaging principle, bubble feature images can be captured from two different view angles. The least square ellipse fitting algorithm is used to figure out the feature parameters from the captured images. Then the 3D volume of bubble can be quantitatively measured. Compaerd with the traditional volume estimation methods based on single perspective imaging, it can effectively reduce the loss of bubble feature information. In the experiment, the 3D volume reconstruction of bubbles from dual perspective images is conducted, and the variation of bubble volume in the bubble rising process is studied. The results show that the measurement accuracy based on the proposed 3D method is higher than those based on traditional methods. The volume of rising bubble is periodically changed, which indicates that bubble achieves periodic rotation and deformation in the rising process.     

Photostimulated Au Nanoheaters in Polymer and Biological Media: Characterization of Mechanical Destruction and Boiling

Agglomerated gold nanoparticle clusters embedded in polyelectrolyte films are optically excited, which results in local ablation of material from the polyelectrolyte films and in some cases leads to the formation of a gas bubble. Evidence is given that this process is mediated by superheating of the medium around the excited gold nanoparticle clusters. This process is highly dependent on the medium used. Besides the boiling point, salt and proteins in the medium also affect the formation of gas bubbles. These data demonstrate that the type of medium must be considered when describing light‐mediated heating of gold nanoparticle clusters, which are fixed in a matrix surrounded by medium.     

Morphology‐Control Strategy of the Superhydrophobic Poly(Methyl Methacrylate) Surface for Efficient Bubble Adhesion and Wastewater Remediation

As one common form of gas existing in aqueous environment, gas bubbles have attracted considerable worldwide attention, owing to their promising applications in industrial production and daily life, such as pressure sensors, the recovery of valuable minerals from ores, aeration process, and water treatment. Usually, the behaviors of gas bubbles in aqueous environment are mainly dominated by buoyancy force. It drives the gas bubbles out of aqueous medium rapidly, which is unfavorable in various processes, especially in wastewater treatment. In this paper, various types of superhydrophobic poly(methyl methacrylate) (PMMA) sheets are facilely fabricated, such as five‐pointed star, triangle, circular, and ellipse. Compared with other shapes of superhydrophobic PMMA sheets, the prepared superhydrophobic PMMA circular sheet is capable of efficiently adhering gas bubbles and subsequently elongating their retention time in an aqueous environment. Furthermore, superhydrophobic PMMA circular sheet arrays are prepared, which can greatly improve the degradation efficiency of methyl blue by ozone (O₃). The investigations indicate that the present approach will find wild applications in bubble‐related fields and provide people with inspirations to develop efficient methods to manipulate gas bubbles in aqueous environment.     

Bubble behavior characteristics based on virtual binocular stereo vision

The three-dimensional (3D) behavior characteristics of bubble rising in gas-liquid two-phase flow are of great importance to study bubbly flow mechanism and guide engineering practice. Based on the dual-perspective imaging of virtual binocular stereo vision, the 3D behavior characteristics of bubbles in gas-liquid two-phase flow are studied in detail, which effectively increases the projection information of bubbles to acquire more accurate behavior features. In this paper, the variations of bubble equivalent diameter, volume, velocity and trajectory in the rising process are estimated, and the factors affecting bubble behavior characteristics are analyzed. It is shown that the method is real-time and valid, the equivalent diameter of the rising bubble in the stagnant water is periodically changed, and the crests and troughs in the equivalent diameter curve appear alternately. The bubble behavior characteristics as well as the spiral amplitude are affected by the orifice diameter and the gas volume flow.     

Hunting Down the Bubble Makers in Fabs

Based on a simulated Non Volatile Memory fab, we employ data-mining to identify and quantify the apparent causes of work in process bubbles along the process. The chosen bubble formalization methods proved able to detect the phenomenon and enabled its occurrence frequency to be forecasted. In the chosen environment, bubbles seem to be highly correlated with the utilization patterns of the process segment considered.      

乙醇辅助激光烧蚀切割硅晶圆工艺

为了减小激光切割硅晶圆时的热效应,选择去离子水作为辅助液体进行激光切割实验,研究了水下切割时激光烧蚀激发气泡对硅片表面造成的不良影响。为解决水下激光切割进程中诱导气泡大面积粘结在硅片表面的问题,提出了去离子水混入乙醇溶液的实验方案,分析了水下激光切割中激光参数和乙醇浓度对切割质量的影响。实验结果表明,采用乙醇溶液作为辅助介质能明显减少粘结气泡的数量,减轻气泡破溃冲击带来的负面影响。实验采用乙醇浓度5 wt.%时切割得到的硅片比纯水中切割得到的硅表面影响区减小50%以上、切缝宽减幅约20%,有效提升了激光切割质量。     

利用光学摄影术研究尾流气泡规律进展

舰船尾流中气泡对尾流特性的研究起着重要的作用.尾流中气泡的形状、大小以及数密度分布都是探测尾流的基础.用光学摄影方法研究尾流气泡具有直观、简便的特点.文章综述了自1979年以来各种研究气泡尾流的光学摄影方法,并对未来的研究重点提出了一些建议.