<chr_abbr type="frq" class="ss" expan="et" cert="yes">et2</chr_abbr> force <chr_abbr type="frq" class="ss" expan="et" cert="yes">et1</chr_abbr>hardi<chr_abbr type="reg" class="dc" expan="" cert="no">m-hbar</chr_abbr><chr_var letter="s" var="long">∫</chr_var> li<chr_abbr type="reg" class="sc" expan="cro" cert="no">c-o</chr_abbr>i<chr_var letter="s" var="long">∫</chr_var>t 