Abstract: The present invention concerns a method and a system for measuring the thermal diffusivity. Said method comprises the steps of: subjecting a surface region of an object to a modulated heating beam (3) while providing a signal (MLS) thereof, the heated spot or area (4) of the surface of the sample (2) having a definitive diameter and a fixed intensity distribution profile; providing a signal (MTS) proportional to the temperature of the heated spot area (4); determining the phase difference between the modulated beam signal (MLS) and the resulting modulated temperature signal (MTS); and using said determined phase difference and the associated frequency to work out the thermal diffusivity value of said object (2).

Abstract: The present invention concerns a method and a system for measuring the thermal diffusivity. Said method comprises the steps of: subjecting a surface region of an object to a modulated heating beam (3) while providing a signal (MLS) thereof, the heated spot or area (4) of the surface of the sample (2) having a definitive diameter and a fixed intensity distribution profile; providing a signal (MTS) proportional to the temperature of the heated spot area (4); determining the phase difference between the modulated beam signal (MLS) and the resulting modulated temperature signal (MTS); using said determined phase difference and the associated frequency to work out the thermal diffusivity value of said object (2).

Abstract: A system of identifying materials and equipment consisting of small metal plates applied to them on their concealed surface and in which identifying means are provided consisting of incisions or blind holes which are detected under scanning or by multiplex technology using ultrasonic transducers which emit ultrasonic waves and which detect the ultrasonic signals reflected by the concealed surface, which set up a different binary coded sequence of return signals as a function of the markings made on the concealed surface of the small plate which is applied to the material.

Abstract: A device for correcting the frequency response of an electromechanical transducer, thus allowing said transducer to be used over a wide frequency band and set at or near its resonance frequency. The device includes a delay element having substantially the inverse transfer function of said transducer. An amplifier may be connected between said transducer and said delay element. Said delay element may comprise a variable delay line such as an adjustable length of coaxial cable, and may also include an integrated delay line.