ELEMENTARY PARTICLE THEORY GROUP. SOME DISCUSSIONS ON THE STRUCTURE WAVE FUNCTIONS OF MESONS FOR THE INSTANTANEOUS INTERACTION APPROXIMATION (Ⅰ)——GENERAL PROPERTIES OF WAVE FUNCTIONS OF MESONS IN THE INSTANTANEOUS INTERACTION CASEJ. Acta Physica Sinica, 1976, 25(4): 316-323. DOI: 10.7498/aps.25.316