d=50:10:700;
x=log10(d);

xm=2.41;
sig=0.216;
sg=2*sig*sig;
M=23.1*1000;
%mm=1/M;
C1=sqrt(2/3.14)/sig;
C=M/10.^xm;
p=C/C1*exp(-((x-xm).^2)/sg);

lp=log10(p);