This document presents the principle of ultrasonic distance measurement is described, the main error sources of ultrasonic distance measurement are analyzed also. A method of improving precision of ultrasonic distance measurement in air, in which the transmission speed of ultrasonic wave if corrected by measured air temperature and the forward edge of receive wave can be determined accurately b...

Aiming at the problem that echo signal is hard to recognize caused by ultrasonic energy’s overquick dispersion and attenuation, a kind of ultrasonic horn is designed. According to the acoustic theory analysis, the ultrasonic horn can increase its radiation energy by improving impedance matching. The ultrasonic horn can make the directivity of sound source sharper and energy more centralized bec...

it has been proved that ultrasonic energy can considerably increase the amount of oil recovery in animmiscible displacement process. although many studies have been performed on investigating theroles of ultrasonic waves, based on the best of our knowledge, little attention has been paid to evaluatewave attenuation parameter, which is an important parameter in the determination of the energydel...

continuous exposure to high-energy ultrasonic waves depolymerises macromolecules in solutions and produces a permanent reduction in viscosity. different factors affect the efficiency of this ultrasonic depolymerisation. in this work ultrasonic degradation of one commercially important hydrogel based on acrylic acid and acrylamide was carried out in aqueous solution at room temperature (25oc). a...

We conducted irradiation experiments with riverine, estuarine, and marine water samples to investigate the possibility of photochemical methane (CH4) formation. CH4 photoproduction was undetectable under oxic conditions or in the absence of methyl radical precursors indicating that its photochemical formation is negligible in the present ocean. Significant photochemical CH4 production was obser...

Research into the photochcmistry of biopolymcrs has increased in scope and scale to such an extent in recent years that it has become necessary to limit this review to a consideration of photochemical approaches to the structure of polynucleotides. Treatment proceeds from the constituent monomers to the polymer to emphasize the changes in photophysical and photochemical properties of the monome...

This study presents a compressed sensing (CS) based sampling approach for repetitive ultrasonic signal. Proposed system considers recovering ultrasonic signal with high equivalent sampling frequency from samples captured using analog-to-digital converter (ADC) clocked at a rate lower than Nyquist rate. A basis function is constructed to realize ultrasonic signal sparse representation, which pav...

The optimization problem of ultrasonic testing instrument is studied in this paper. Using ultrasonic nondestructive testing technology to detect quality of products or parts, because the function of conventional ultrasonic testing instruments is custom-built and defined by manufacturers, it is very difficult to meet ever-changing testing requirements such as testing accuracy, testing efficiency...