The study of asymmetrical patterns of the light diffracted by ultrasonic waves has been utilized in the last decades to investigate ultrasonic wave distortions caused by the nonlinearity of the medium. In contrast to the investigation of diffraction patterns in space, a novel optical method is proposed in this work to analyze, in the frequency domain, the phase modulation (related to the Raman-...

The autonomous navigation technology of INS has always attracted the attention many scholars. In satellite-denied environment, making full use auxiliary sensors with characteristics can suppress dynamic error generated by in effectively. However, like an odometer (OD) and laser doppler velocimeter (LDV) will cause instability to system. To solve above problems, we propose improved inerital-base...

We analyzed tricuspid regurgitation noninvasively using ultrasonic pulsed Doppler and two-dimensional echocardiography in 66 patients in whom tricuspid regurgitation was suspected from routine clinical evaluation. All of the patients also underwent right ventriculography. Ten healthy subjects served as controls. In 62 of 66 patients, the study was adequately performed. In 58 of 62 patients, pan...

Acoustic communication has an important role in the reproductive behaviour of anurans. Although males of the concave-eared frog (Odorrana tormota) have shown an ultrasonic communication capacity adapted to the intense, predominately low-frequency ambient noise from local streams, whether the females communicate with ultrasound remains unclear. Here we present evidence that females exhibit no ul...

Regurgitant flow was analysed in 40 cases of mitral regurgitation, using combined ultrasonic pulsed Doppler technique and two dimensional echocardiography. Abnormal Doppler signals indicative of mitral regurgitant flow were detected in reference to the two dimensional image of the long axis view of the heart and the short axis view at the level of the mitral orifice. The overall direction of re...

Development of techniques for the continuous measurement of regional blood flow and vascular resistance in intact small animals has been impeded primarily by the bulkiness of flow probes. The availability of an ultrasonic pulsed Doppler flowmeter system enabled us to construct miniaturized probes using 1-mm-diameter piezoelectric crystals that emit a 20-mHz signal and receive the reflected soun...

The ultrasonic Doppler method was employed to time the rapid movements (opening and closure) of the mitral and aortic valves. To exclude signals due to slowly moving structures (heart walls), the Doppler tracing was processed by a filter that eliminated low frequencies. Clear tracings containing two deflections, one due to the opening and the other to the closure of each valve, were obtained. T...