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For practical use, the transition distances derived by the spheroidal model according to several definitions are synthesized as an approximate function of the body-length (L) to wavelength-in water (\u03bb) ratio, i.e., 0.025L\/\u03bb1.4. The formula for the transition distance of ultrasonic transducers should not be used to estimate that of the fish.<\/jats:p>","DOI":"10.1121\/10.0044568","type":"journal-article","created":{"date-parts":[[2026,8,7]],"date-time":"2026-08-07T11:54:17Z","timestamp":1786103657000},"page":"1125-1135","update-policy":"https:\/\/doi.org\/10.1063\/aip-crossmark-policy-page","source":"Crossref","is-referenced-by-count":0,"title":["Near-to-far-field transition distance of backscattering from prolate spheroids and fish"],"prefix":"10.1121","volume":"160","author":[{"ORCID":"https:\/\/orcid.org\/0009-0003-5931-7096","authenticated-orcid":false,"given":"Masahiko","family":"Furusawa","sequence":"first","affiliation":[{"name":"Tokyo University of Marine Science and Technology , Minato, Tokyo 108-8477,","place":["Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"231","published-online":{"date-parts":[[2026,8,7]]},"reference":[{"key":"2026080707541257400_c1","volume-title":"Principles of Underwater Sound","year":"1983","edition":"3"},{"key":"2026080707541257400_c2","doi-asserted-by":"publisher","first-page":"1511","DOI":"10.1121\/1.4895701","article-title":"Discriminating between the near field and the far field of acoustic transducers","volume":"136","year":"2014","journal-title":"J. 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