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为了实现大面积图案化铜微纳结构的制备,基于液相下激光烧蚀技术,以硅片为衬底,将其浸没在含有Cu2O微米粒子的乙醇溶液中,采用纳秒脉冲激光进行加工。研究了激光功率、扫描速度和扫描次数对铜微纳结构的影响,分析了图案化铜微纳结构的形成机制,并研究了图案化铜微纳结构的浸润特性。扫描电子显微镜结果表明,随着激光功率、扫描速度和扫描次数的增加,图案化铜微纳结构中的铜颗粒熔融现象加剧,光斑中心区域的纳米颗粒粒径逐渐增大,光斑交界处形成呈现周期性分布的微米量级单元结构。能量色散X射线光谱证明少量Cu元素分布在光斑中心区域,大量Cu元素集中在光斑交界处。随着扫描次数的增加,样品表面粗糙度和纯净水/食用油接触角均呈现先上升后下降的趋势。当扫描次数为6时,表面平均粗糙度为(1.3±0.11)μm,纯净水接触角可达(155.2±1.5)°,食用油接触角达(100.0±1.3)°。该大面积图案化铜微纳结构制备方法简单快速,无粉尘污染,在微流体芯片、集水系统和废水处理等领域具有广泛的应用前景。 相似文献
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在单颗粒气溶胶质谱分析中,不同颗粒质谱图之间发生质谱偏移,谱峰质量数难以准确测定的现象已经被多次观察到。这种现象的存在使得应用单一的校准参数校准质谱图时,产生质谱峰辨认的不确定性。不同颗粒质谱图之间最大的偏移取决于电离激光光斑的大小。当校准参数不准确时,某质谱峰偏离正确m/z值的大小与该质谱峰的质量数呈线性相关。从理论上证明了这种偏移产生于颗粒物在激光光斑内电离位置的不同。为解决单一校准参数带来的不可避免的误差,提出了一种可编程的算法来自动找出每个颗粒物质谱的最优校准参数,以实现单颗粒质谱图的准确的质量校准。 相似文献
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光针轮廓扫描技术测量内螺纹曲面 总被引:1,自引:0,他引:1
分析了激光光针扫描在测量内螺纹曲面时的特性及影响精度的因素。根据光斑在被测面的噪声分布特点,采用中值滤波与小波阈值去噪相结合的综合滤波算法对光斑图像进行了去噪处理,其中中值滤波可以有效地消除光斑图像中的脉冲噪声,而基于小波变换的阈值去噪算法可以消除图像中的高斯噪声。通过综合滤波算法对光斑图像进行处理,可以有效消除激光光斑噪声,消除图像噪声对测量精度的影响,同时保持了光斑图像的细部特征。根据激光光斑图像在倾斜被测物体表面光强分布特点,设计了近似圆拟合算法来确定光斑中心,该算法相对传统算法具有计算量小、计算效率高,适合在线检测的特点,可以克服测量面倾斜对激光光斑中心的影响。利用采用上述方法的坐标机激光光针扫描系统,对标准内螺纹量规进行测量,对比应用前后的测量结果,螺距精度提高了0.48 mm,中径测量精度提高了0.44 mm,牙型角精度提高0.57°。 相似文献
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对结合激光辅助掺杂和毛化方法合成的光伏电池用Sb掺杂非晶硅薄膜进行了研究.首先,用阈值通量为460mJ/cm2的激光照射镀有200~300 nm厚Sb的非晶硅薄膜进行施主扩散.为激活施主,样品用230mJ/cm2的低激光通量再一次进行处理.进行施主激光扩散和活化时,激光光斑的重叠度达到光斑大小的90%,因此随后诱发了薄... 相似文献
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根据激光光线聚焦状态不同对应被测面上激光光斑形状不同的特点,通过引入辅助激光束,分析了调焦CCD采集的激光光斑图像信息,进而根据光斑形状及半径等信息确定被测面对焦状态。针对实验中每隔相同离焦距离采集的一系列光斑图像,提出了相应的图像处理方案,以提取所需光斑半径信息,进而进行光斑半径与离焦量转换。实验结果表明,光斑半径与离焦量呈线性关系,最大线性范围灵敏度为2.342像素/μm,最高可实现0.43μm分辨率。 相似文献
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目前,对管道内腔为自由曲面的截面轮廓进行高精度测量是行业难题。拟将多个不同测量范围的激光位移传感器放置于管道内腔中,采用旋转的方式对内腔进行测量,将得到的测量数据进行归一化处理后获得被测管道内腔截面轮廓形状。分析测量过程中激光光斑的变化情况,针对光斑图像的多峰、散斑、平顶与形状变化等现象,提出了一种基于传统灰度重心法进行粗定位的距离倒数加权多项式插值亚像素光斑中心定位方法。采用中值滤波对光斑图像进行预处理,通过自适应阈值分割法从环境背景光强中分离出光斑中心定位区域。通过MATLAB仿真与灰度重心法、加权灰度重心法与高斯拟合法传统光斑中心定位方法相比,结果表明,光斑中心定位精度达到0.01 pixel,在激光光斑中心定位精度和稳定性方面有一定的改善,明显优于传统的光斑中心定位算法。 相似文献
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激光光斑位置精确测量系统 总被引:6,自引:1,他引:5
设计了一种激光光斑位置测量系统,用于提高激光照射器监测系统测量激光光斑位置时的测量精度.分别介绍了测量系统的组成及它们的信号连接关系.针对激光光斑图像采集过程中的后向散射现象,提出基于异步距离选通的激光后向散射抑制技术.为了克服大气湍流扰动对激光光斑成像的影响,利用改进的盲解卷积算法对激光光斑图像进行事后图像处理.最后,对光斑图像进行畸变校正,并利用高斯曲面拟合算法提取光斑位置.设计了若干仿真实验,并应用该系统处理了实际外场实验.结果表明,所设计的激光光斑位置测量系统的测量精度不超过0.3 pixel. 相似文献
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针对激光模拟射击系统对激光光斑进行快速、高精度质心定位的要求,提出了一种基于视频序列图像的光斑检测与高精度质心定位方法。该方法首先利用帧间差分图像和噪声估计参数对射击突发事件进行检测;然后利用噪声估计方法确定光斑的分割阈值,结合形态学滤波对目标光斑和背景噪声进行有效分割,提取光斑区域,同时降低窗口内外噪声。最后,用4帧差分图像合成1帧高分辨率的图像来抑制图像噪声和计算误差的影响,实现光斑质心的高精度定位。实验结果表明,本文方法的光斑质心定位精度与稳定性均优于传统的方法;其中光斑质心定位精度达到了亚像素级别,稳定性度量平均值为0.000 49,优于传统方法的0.002 97。得到的结果显示,提出的方法有助于提升激光射击系统的性能。 相似文献
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On-line non-intrusive particle size measurement of pulverised fuel through digital imaging 总被引:1,自引:0,他引:1
Carter Robert M Yan Yong 《仪器仪表学报》2007,28(11):1942-1946
This paper presents the basic principles of particle size measurement and latest industrial results recorded using an innovative optical instrumentation system designed to measure the size distribution of particles in a pneumatic suspension.The system is non-intrusive and cost-effective.A low-cost CCD camera is used to capture images of the particulate flow field,which is illuminated by a low-cost pulsed laser sheet generator.The particle size distribution is then determined by processing the particle images through the use of novel processing algorithms.Experimental results obtained in the past on a small scale particle flow test rig have demonstrated that the system is capable of measuring the size distribution of pneumatically conveyed particles with an accuracy of a few percent.For the present paper results obtained when testing the system at a 4 MW industrial test facility are presented.Comparisons are made with both off-line reference data achieved through sieving and on-line laser diffraction data recorded using an intrusive,extractive,Malvern Instruments system.In general there is good agreement between results when considering the characteristics and limitations of the individual methodologies.The novel imaging system shows itself to be rugged,practical and useful under genuine industrial conditions. 相似文献
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《Flow Measurement and Instrumentation》2005,16(5):309-314
This paper presents a novel instrumentation system that uses a combination of electrostatic and digital imaging sensors. An inferential approach is adopted for the mass flow measurement of particles, velocity and volumetric concentration of particles being measured independently. The velocity of particles is determined by cross correlating two signals derived from a pair of electrostatic sensors and the volumetric concentration of particles is obtained using a novel digital imaging sensor, which also provides particle size distribution data. The basic principles and limits of operation of the imaging sensor are discussed and explained. Results obtained from a pneumatic conveyor are presented which demonstrate good performance of the measurement system for both mass flow metering (accurate to about ±6%) and particle sizing (reliable to around ±2.5%). Particle size distribution results are also included and the insensitivity of particle sizing to changes in velocity and concentration is assessed. In addition, on-line sizing results are compared to off-line results, measured using an accepted laser diffraction based instrument, and good agreement is observed. In general, the results obtained are encouraging and the system shows great promise. 相似文献
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激光衍射法测量颗粒粒径过程中,面阵CCD接收到的待测颗粒的衍射图样总是不可避免受到噪声污染,直接影响粒度的反演精度。通过对测试原理及衍射图样的深入分析,提出了采用曲线窗口旋滤波对衍射图样进行预处理的方法,并进行了粒子群粒度反演的数值模拟实验。经过旋滤波处理后的单峰粒子和双峰粒子的粒度分布误差从直接粒度反演的42.36%、46.099/6和39.06%、35.7%分别减小到5.3%、6.17%和6.48%、7.33%,实验结果证明了采用曲线窗口旋滤波方法,粒度分布误差明显降低。 相似文献
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Acoustic emission (AE) technology is a promising approach to non-intrusively measure the size distribution of particles in a pneumatic suspension. This paper presents an experimental study of the AE sensing technology coupled with signal processing algorithms for on-line particle sizing. The frequency characteristics of the AE signals under different experimental conditions are studied and compared. Initially, the characteristics of the background noise and AE signals are compared in the frequency domain for different air velocities and particle feeding rates. Through short-term energy analysis the working features of the suction unit and the vibration feeder are revealed. To find the effective characteristic frequency band of the AE signals, a multiple scanning and accumulation method assisted with a Savitzky–Golay smoothing filter is used to denoise the power spectra of the signals. Wavelet analysis is also deployed to denoise the signals. The denoising performance of different wavelet parameters (wavelet function, decomposition level and thresholding) is compared in terms of signal-to-noise ratio and signal smoothness. Finally, particle size is predicted through a neural network with energy fraction extracted through wavelet analysis. Experimental results demonstrate that the relative error of the particle sizing system is no greater than 23%. 相似文献
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液固两相流动广泛存在于工业过程中,其粒径分布信息在线测量对生产优化与控制十分重要。超声法作为无扰动式多相流动参数测量方法,其衰减特性与固相颗粒粒径、体积分数等密切相关,可用于实现粒径分布在线测量。本文搭建液固两相介质超声衰减实验装置,装置采用石英砂作为固相颗粒,自来水为液相,利用线性调频超声信号激励研究液固两相介质的超声衰减特性。实验结果表明,随着激励频率和固相体积分数的升高,超声衰减系数逐渐增加,采用Twomey及遗传算法等对液固两相介质粒径分布进行反演,测试结果与马尔文激光粒度分析仪的粒径分布结果相比,相关系数为0.918。 相似文献