function trfc(tr_fc) {

	ln = Math.log(9);
	trtf_PI = 2*(Math.PI);
	tr =  tr_fc.trtf.value*1;
	Ans = (ln/(trtf_PI*tr)/1e6);
	//alert('ln='+ln+'¥n'+'PI='+PI+'¥n'+'tr='+tr+'¥n');
        tr_fc.tr_fc.value = Ans;
	}