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300MHZ scanning laser acoustic microscope   总被引:1,自引:0,他引:1  
The knife—edge and harmonic technique in the Scanning LaserAcoustic Microscope is studied in this paper.The operating frequency of theSLAM can be increased from 100MHz to 300MHz by using the harmonic tech-nique.The acoustic images of some samples are obtained on our SLAM at300MHz.  相似文献
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激光扫描声学显微镜光学系统的设计   总被引:1,自引:0,他引:1  
半导体激光器具有半导体和固体器件的许多优点:结构紧凑、效率高、价格便宜、长寿命,在许多方面优于气体激光器,因此在一些测量领域有较好的应用前景。本文基于棱镜对光的一维压缩及新型半导体激光器,对激光扫描声学显微镜的光学系统进行了新的设计,给出了相关数据及具体技术指标,实验证实其光学性能满足要求。整个光学系统具有结构紧凑、可靠性高、使用方便等特点,现已用于激光扫描声学显微镜定型设计。  相似文献
3.
发动机叶片激光打孔的声显微检测   总被引:1,自引:0,他引:1       下载免费PDF全文
本文用声显微技术对发动机叶片上的激光打孔进行了检测研究,发现沿孔周存在的周向裂纹和径向裂纹。指出,径向裂纹是影响叶片安全使用寿命的主要因素。  相似文献
4.
In this paper the experimental results concerning the distance resolution measurements performed with the air microscope operating with a focussing transducer at 1.27 MHz are presented. A distance resolution of 3 nm has been achieved, corresponding to the average distance between two molecules in air at normal conditions. The influence of air temperature variations on the distance measurements has been taken into account.  相似文献
5.
We have constructed a fast laser-based surface acoustic wave (SAW) microscope, which may be thought of as a non-perturbing scanning acoustic microscope. The instrument is capable of rapid high resolution vector contrast imaging at several discrete frequencies, without any damage to the sample. Tailoring the generating optical distribution using computer-generated holograms allows us to both focus the acoustic waves (increasing their amplitude) and to spread the optical power over the sample surface (preventing damage). Accurate quantitative amplitude and phase (velocity) measurements and unique acoustic contrast mechanisms are possible with our instrument based on this technology due to the non-perturbing nature and the instrument geometries.However, the complexity of the optical generation profile leads to a strong dependence on material properties such as the SAW velocity and material anisotropy. We address these issues in this paper, and demonstrate how a spatial light modulator may be used to adapt the generating optical distribution to compensate for the material properties. This facilitates simpler alignment and velocity matching, and, combined with an acoustic wavefront sensor, will allow real-time adjustment of the generating source to enable imaging on anisotropic materials.  相似文献
6.
本文描述一台虚拟式扫描声显微镜及应用技术研究,它的硬件特别简单,仅由一台带有超高速A/D卡和快脉冲收发卡的PC机和机械扫描系统组成,主要的功能均由软件完成,脉冲收发卡仅包括脉冲产生和高频放大器,A/D卡采用PCI总线,采样率1GSPS,数据传输率100MB/s,系统能采集并实时显示频率达百兆的未检波回波信号,采修订本以的信号经软件处理,可在屏幕上实时显示样品的A、B、C型幅度像或相位像,仪器利用信号处理技术提高信号的信噪比;进行特征提取,识别,该仪器在材料识别,电子、光电子器件和焊接质量检测等方面功能较强,具有广阔的开发应用前景。  相似文献
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A new method for two-dimensional acoustic impedance imaging for biological tissue characterization with micro-scale resolution was proposed. A biological tissue was placed on a plastic substrate with a thickness of 0.5 mm. A focused acoustic pulse with a wide frequency band was irradiated from the “rear side” of the substrate. In order to generate the acoustic wave, an electric pulse with two nanoseconds in width was applied to a PVDF-TrFE type transducer. The component of echo intensity at an appropriate frequency was extracted from the signal received at the same transducer, by performing a time–frequency domain analysis. The spectrum intensity was interpreted into local acoustic impedance of the target tissue. The acoustic impedance of the substrate was carefully assessed prior to the measurement, since it strongly affects the echo intensity. In addition, a calibration was performed using a reference material of which acoustic impedance was known. The reference material was attached on the same substrate at different position in the field of view. An acoustic impedance microscopy with 200 × 200 pixels, its typical field of view being 2 × 2 mm, was obtained by scanning the transducer. The development of parallel fiber in cerebella cultures was clearly observed as the contrast in acoustic impedance, without staining the specimen. The technique is believed to be a powerful tool for biological tissue characterization, as no staining nor slicing is required.  相似文献
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