Acoustic interferometer

About: Acoustic interferometer is a research topic. Over the lifetime, 1493 publications have been published within this topic receiving 19355 citations.

K/sup +/ detection using shear horizontal acoustic modes

Abstract: An acoustic delay line sensor for the detection of potassium ion concentration in water has been implemented and tested. The device uses the propagation of shear horizontal (SH) waves in a piezoelectric plate (Love waves) in order to minimize acoustic energy loss in the liquid. One of the plate surfaces is covered with a polyvinyl-chloride-valinomycin membrane, a well-known ligand for the detection of potassium ions. The devices has shown a fairly good linearity of the response in the analyzed pK/sup +/ range of K/sup +/ concentration between 1.49 and 4. The operation is reversible and the response is highly reproducible. Measurements have demonstrated a high selectivity of the device with respect to exposure to Na/sup +/ solutions. >

Ultrasonic Velocity and Thermal Relaxation in Dry CO2 at Moderate Pressures

Abstract: The velocity and absorption of ultrasound in dry CO2 have been measured along the 50.8° isotherm with a Hubbard‐type, variable path, recording acoustic interferometer at six frequencies from 300 kc to 7 mc and from 0.3 to 250 atmos, i.e., up to liquid densities. Velocity dispersion is clearly shown in addition to the change in velocity attributable to the nonideality of the gas. The values of the frequency/density ratio f/ρ, at which the transition from V02 to V∞2 is half‐completed as the pressure is lowered, and at which the maximum absorption per wavelength occurs, were measured wherever possible. From these determinations the relaxation time of the gas has been determined as a function of the density. It proves to be inversely proportional to the density up to the highest density reached (0.8 g/ml), indicating that ternary collisions have not become important and that the number of binary collisions required to excite the internal vibrations does not vary with density. At 50.8° and one atmosphere the r...

Method and device for the measurement of the phase shift of the waves in a ring interferometer

Abstract: 1. A method of measuring the phase difference of electromagnetic waves circulating in opposite sense in a ring interferometer, comprising the step of generating an electromagnetic wave, separating this electromagnetic wave into two phase components which are fed into the end of the ring in order to generate the waves ciculating in opposite sense, modulating the phases of the two waves in periodical and reciprocal manner, recombining the two waves at the ends of the ring and detecting the recombined waves, characterized in that in the modulating step the phase of the two waves circulating in opposite sense are modulated at least at one end of the ring according to a function satisfying the relation PHI(t)=PHI(t+2 tau), wherein tau is the time necessary for each wave for passing through the optical way provided by the ring, and at that the step of detecting the phase difference between the two recombined waves is carried outs by measuring, at the frequency (1/2 tau) or at an entire multiple (k) of this frequency the optical power of the component of the recombined waves proportional to the sine of the phase difference between the waves.

Non-contact measurements of ultrasonic waves on paper webs using a photorefractive interferometer

Abstract: An apparatus and method for non-contact measurement of ultrasonic waves on moving paper webs employs a photorefractive interferometer. The photorefractive interferometer employs an optical head in which the incident beam and reflected beam are coaxial, thus enabling detection of both in-plane and out-of-plane waves with a single apparatus. The incident beam and reference beams are focused into a line enabling greater power to be used without damaging the paper.