With Laser Reflective Tomography（LRT）,the near fields of ultrasonic transducers were measured and analyzed.The principle of LRT measurement of ultrasonic field distribution was introduced and an experimental system ...With Laser Reflective Tomography（LRT）,the near fields of ultrasonic transducers were measured and analyzed.The principle of LRT measurement of ultrasonic field distribution was introduced and an experimental system was set up.Acoustic pressure of a multiple element piston transducer was measured by using of a laser vibrometer.Its distribution in amplitude and phase was obtained.The acoustic pressure in the same region was measured with a needle hydrophone to validate the LRT method.Furthermore,through reconstruction of acoustic fields,it indicated that LRT method is suitable for predicting the distribution on transducers＇surface and conditions of active elements.展开更多
Scanning near-field acoustic microscope （SNAM） combines the ultrasonic detection technology with scanning near-field microscopy. The main characteristic of such microscope is that the acoustic wave is produced or de...Scanning near-field acoustic microscope （SNAM） combines the ultrasonic detection technology with scanning near-field microscopy. The main characteristic of such microscope is that the acoustic wave is produced or detected in near-field area whether ultrasonic transducer acts as generator or detector. The resolution of SNAM can reach to nanometer scale. First, two typical SNAMs, scanning electron acoustic Inicroscope and scanning probe acoustic microscope, will be introduced in this paper. The working principle of our homemade SNAM based on a commercial scanning probe microscope will be reported, together with some recent results from this homemade SNAM.展开更多
文摘With Laser Reflective Tomography（LRT）,the near fields of ultrasonic transducers were measured and analyzed.The principle of LRT measurement of ultrasonic field distribution was introduced and an experimental system was set up.Acoustic pressure of a multiple element piston transducer was measured by using of a laser vibrometer.Its distribution in amplitude and phase was obtained.The acoustic pressure in the same region was measured with a needle hydrophone to validate the LRT method.Furthermore,through reconstruction of acoustic fields,it indicated that LRT method is suitable for predicting the distribution on transducers＇surface and conditions of active elements.
基金supported by the National Natural Science Foundation of China (Grant Nos.50971011 and 10874006)Beijing Natural Science Foundation (Grant No.1102025)Research Fund for the Doctoral Program of Higher Education of China (Grant No.20091102110038)
文摘Scanning near-field acoustic microscope （SNAM） combines the ultrasonic detection technology with scanning near-field microscopy. The main characteristic of such microscope is that the acoustic wave is produced or detected in near-field area whether ultrasonic transducer acts as generator or detector. The resolution of SNAM can reach to nanometer scale. First, two typical SNAMs, scanning electron acoustic Inicroscope and scanning probe acoustic microscope, will be introduced in this paper. The working principle of our homemade SNAM based on a commercial scanning probe microscope will be reported, together with some recent results from this homemade SNAM.
