Korea Atomic Energy Research Institute

Doo-Byung Yoon

Jin-Ho Park

Soon-Woo Han

Hong Pyo Kim

Jang-Soo Lee

To Kang

Jeong Han Lee

An apparatus for detecting leakage of a pipe by using a distance difference-frequency analysis includes: vibration detecting sensors, which are mounted at a predetermined distance in a longitudinal direction of a pipe and are configured to measure vibration signals of the pipe; and a control unit, which is configured to calculate a cross-correlation function by using the vibration signals, to reveal time delay information in the frequency domain by calculating time-delay frequency analysis diagram for the cross-correlation function, to calculate a distance difference-frequency analysis diagram by applying compensation conversion using frequency-dependent propagation speed information to the time-delay frequency analysis diagram, and to detect a leakage component of the pipe in the distance difference-frequency analysis diagram.

Apparatus and method of detecting leakage of pipe by using distance difference-frequency analysis

Provided are an apparatus and a method for measuring a nonlinearity parameter using laser, and more particularly, an apparatus and a method for measuring a nonlinearity parameter using laser for computing the nonlinearity parameter by irradiating laser of a toneburst signal on a surface of a sample by non-contact type laser so as to excite the sample, irradiating measurement laser beam on the surface of the sample so as to receive displacement information occurring on the surface of the sample over time, measuring the displacement in an interferometer principle, and performing a bandpass filtering for the measured signal so as to measure amplitude Aof a component of a fundamental frequency and amplitude Aof a component of a secondary harmonic wave.

Apparatus and method for measuring nonlinearity parameter using laser

Disclosed are an apparatus for detecting pipe wall thinning, which measures a natural frequency of a pipe and determines a level of the pipe wall thinning, and a method thereof. The apparatus for detecting the pipe wall thinning includes a hitting memberfor hitting the pipe T, a vibration measurement sensorwhich measures a vibration signal generated when the pipe T is hit with the hitting member, and a control partwhich compares the natural frequency calculated from the vibration signal measured from the vibration measurement sensorwith a natural frequency generated from a normal pipe in which wall thinning does not occur, and determines the level of the wall thinning of the pipe T.

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Daejeon, South Korea

Doo-Byung Yoon