نتایج جستجو برای: ultrasonic transducer
تعداد نتایج: 46136 فیلتر نتایج به سال:
abstract-Signals measured in ultrasonic nondestructive evaluation (NDE) of materials are masked by the characteristics of the measuring instruments, the propagation paths taken by the ultrasonic waves, and noise originating from various sources, including the electrical noise. Due to the band-limited characteristics of ultrasonic transducers, the received echoes are degraded by the transducer i...
Integrated ultrasonic backscatter has been related to collagen deposition in fibrotic myocardium. The purpose of our study was to measure the integrated ultrasonic backscatter in the right and left ventricles of 10 normal freshly excised canine hearts and five normal formalin-fixed human hearts. A 2.25 MHz, 50% fractional bandwidth transducer was positioned at the transducer focal distance from...
We report a photoacoustic imager that utilizes a focused laser beam in combination with a 20 MHz ultrasound focusing transducer to obtain micron-resolution tissue images over a long working distance. The imager is based on a ring transducer that combines ultrasonic and laser beams collinearly and confocally in a monolithic element. The combination of focused laser beam and short pulse irradiati...
Piezoelectric transducers have been widely used for the generation and detection of ultrasonic waves for structural health monitoring. Recently, we proposed the use of inductive coupling in order to implement wireless coupling to a Lamb wave transducer. In that transducer the ultrasonic waves were generated by a piezoelectric wafer attached to the surface of a plate. These transducers are effec...
Photoacoustic microscopy has achieved submicron lateral resolution, but its axial resolution is much lower. Here an axial resolution of 7.6 μm, the highest axial resolution validated by experimental data, has been achieved by using a commercial 125 MHz ultrasonic transducer for signal detection followed by the Wiener deconvolution for signal processing. Limited by the working distance, the high...
Accurate estimation of the state charge (SOC) and temperature batteries is essential to ensure safety energy storage systems. However, it very difficult obtain multiple states battery with fewer sensors. In this paper, a joint method for lithium iron phosphate battery’s SOC based on ultrasonic reflection waves proposed. A piezoelectric transducer affixed surface ultrasonic–electric transduction...
According to turning instead of grinding process requirements and traditional working principle of ultrasonic vibration turning, a new idea of imitating grinding of two-dimensional ultrasonic vibration turning is brought firstly, and the mechanism of two-dimens ional ultrasonic vibration turning is elaborated. Based on the MATLAB software, grinding trajectory simulation and honing trajectory si...
Laser-induced spallation is proposed as a powerful means for the investigation of adhesion properties of solid surface films. Ultrasonic pulses are produced at the back side of the sample by the impact of Nd:YAG-laser pulses. At the front side, the induced ultrasonic surface displacements are monitored with a 300 MHz bandwidth fiber-optic interferometer, which is proposed as a versatile point-d...
A full matrix capture technique is presented that allows for real-time imaging through a non-planar surface where the geometry is known. For an identified geometry the point of incidence at the refractive interface is calculated using Fermat’s principle and iterative techniques for each possible transducer position which is pre-processed ahead of the inspection. This information is combined wit...
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