“…RUS has been developed and advanced by Anderson et al [23], Ohno [24], Miglioiri et al [25], Ledbetter et al [26], and Maynard [27], and elastic properties of single crystal [28,29], piezoelectric material [30,31], composite [32], and thin films [33] have been studied. RUS is superior to other techniques because it is capable of determining anisotropic elastic constant and being unnecessary to grip the specimen.…”