摘要:
The present invention provides an acoustic capacity measurement method for finding capacity of a container or object by removing effect of the surface area without using an approximate expression of acoustic impedance. The acoustic capacity measurement method for finding capacity of a container under test based on a ratio of pressure changes produced in a reference vessel and the container under test by giving equal alternating capacity changes to the reference vessel and the container under test includes a pressure change ratio calculating step of calculating a ratio between measured values of pressure changes in the reference vessel and the container under test; a rotation step of calculating an acoustic admittance component of the container under test by rotating the calculated pressure change ratio by an angle of θ so that the pressure change ratio will vary at a slope of 1 with respect to changes in a surface area in a complex plane; an oblique coordinate transformation step of transforming the calculated acoustic admittance component into an oblique coordinate system whose axes are given by an imaginary axis and a straight line with a slope of 1; and a capacity calculating step of calculating the capacity of the container under test by multiplying values in a direction of the imaginary axis of the acoustic admittance component transformed into oblique coordinates by a predetermined real number.
摘要:
An electromechanical transducer of the invention comprises a structural unit, an armature (22) , and first and second elastic members (23, 24). The structural unit includes at least one pair of magnets (14, 17), a yoke (11, 12) conducting a magnetic flux generated by the magnets, and a coil (13) supplied with an electric signal. The armature (22) has an inner portion (22a) disposed to pass through an internal space of the structural unit and first and second outer portions (22b, 22c) protruding on both sides from the inner portions, and the armature constitutes a magnetic circuit with the structural unit via two regions through which components of the magnetic flux flow in directions opposite to each other in the inner portion. The first and second elastic members (23, 24) connect between the first and second outer portions of the armature and the structural unit, respectively.