title: Automatic measurement of the nonlinearity parameter B/A in liquid media.
abstract: Using a 19-MHz focused Gaussian beam generated by a LiNbO(3) plate with an inverted polarization layer coupled to an acoustic lens, a method to automatically measure the nonlinearity parameter B/A in liquid media is presented. A liquid sample is poured into a cylindrical cell set with a glass tube on the lens surface. The focusing source emits burst waves. A tungsten rod immersed in the sample so that the top surface is normal to the beam axis behaves as a perfect reflector. The position of the reflector to maximize the amplitude receiving the returned wave determines the sound speed c of the sample. The amplitude measurement for the waves returned from the lens-sample interface and the reflector surface leads to the determination of the density rho and attenuation coefficient alpha, respectively. Then the B/A is finally derived by summarizing the measured result of the 38-MHz second harmonic amplitude contained in the sound returned back from the reflector, together with rho, c and alpha. All these are automatically processed in a short time less than 2 min with the performance of computer controlled instruments.
authors.affiliation: School of Marine Science and Technology, Tokai University, Shimizu-Ku, Shizuoka 424-8610, Japan. ssaito@scc.u-tokai.ac.jp <ssaito@scc.u-tokai.ac.jp>
authors.forename: Shigemi
authors.initials: S
authors.lastname: Saito
authors.forename: Jung-Ho
authors.initials: JH
authors.lastname: Kim
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Nakamura
mesh_terms: D000465:Algorithms; D045424:Complex Mixtures / Q000737:chemistry*; D003198:Computer Simulation; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008422:Materials Testing / Q000295:instrumentation* / Q000379:methods*; D008956:Models, Chemical; D017711:Nonlinear Dynamics; D012542:Scattering, Radiation; D012996:Solutions; D014465:Ultrasonics
chemical_list: D045424:Complex Mixtures; D012996:Solutions