ULTRASONIC INTENSITY MEASUREMENT METHOD

目的是对原始方法进行基础研究， 超声波强度的高空间精确测量 分辨率，独立地同时检测 声场中瞬时压力和质点速度 在很宽的振幅和频率范围内。 长期 goal目标is an instrument工具that would，on the hand一方面，accurate准确， 另一方面，它将是紧凑的，东使用和成本 有效地使得声学和 在设计中可以有规律地使用超声波场， 安全使用仪器和进行生物物理 实验 实际上，超声系统的设计者通常必须依赖于理论 和不准确的测量。 这个问题特别尖锐 关于成像和血流系统，治疗机， 和碎石机。 100%的变化， 任何特定的测量都是常见的， 技术能力水平。 这种困难非常 对政府和仪器制造商来说成本很高， 研究人员，并可以防止充分保护的 人口处于危险之中。 它们也极大地阻碍了准确的 超声波在生物学、物理学及其他领域的应用研究 应用领域，如无损检测。 探索的主要方法将是空间叠加 光学干涉测量， 粒子位移，薄膜压电器件， 有效测量局部声压。 强度是 粒子速度的矢量积，可以由下式计算： 位移和压力。 建议这样一个 测量概念可以克服不准确性， 用于压力测量的压电薄膜的不稳定性， 因为光学子系统可用于周期性的重新校准。 声光效应的同时测量将是 研究它适用于这个问题。 测量 颗粒位移，独立于压力，是必要的， 计算近场和其他非平面中的强度 速度和压力可能不同相的场。

The objective is to conduct basic research on original methods for accurate measurement of ultrasonic intensity with high spatial resolution, detecting independently and simultaneously the instantaneous pressure and particle velocity in an acoustic field over broad ranges of amplitude and frequency. The long term goal is an instrument that would be, on the one hand, accurate, and on the other it would be compact, east to use and cost effective such that accurate characterization of acoustic and ultrasonic fields could be regularly employed in the design and safe use of instruments, and in the conduct of biophysical experimentation. As it is, designers of ultrasound systems often must rely on theory and inaccurate measurements. The problem is especially accute in relation to imaging and blood flow systems, therapy machines, and lithotripters in medicine. Variations of the order of 100% in any particular measurement are common despite a decidedly high level of technological competence. Such difficulties are very costly to the government and to instrument manufacturers and researchers, and can prevent adequate protection of the population supposedly at risk. They also greatly hinder accurate investigations using ultrasonics in biology, physics, and other applied fields such as nondestructive testing. The principal method to be explored will be a spatial superposition of optical interferometric measurements, which measure local particle displacement, with thin-film piezoelectric devices which effectively measure local acoustic pressure. Intensity is the vector product of particle velocity, which can be calculated from the displacement, and pressure. It is proposed that such a measurement concept can overcome the inaccuracies and instabilities of thin piezoelectric films for pressure measurement, since the optical subsystem can be used for periodic recalibration. Simultaneous measurement of the acousto-optic effect will be investigated as it applies to this problem. Measurement of particle displacement, independent of pressure, is necessary to calculate the intensity in near-fields and in other non-planar fields for which the velocity and pressure may not be in phase.