clear, clc
R=[0.1 1 10 100 1000]; % R = [NaCl]/[CuCl2]
yL=(sqrt(2./R+1)); % yL = exp(fΦL)
fiiL=log(yL);
for i=1:5
    fii(:,i)=0:fiiL(i)/100:fiiL(i);
    y=exp(fii);
    X(:,i)=0.5*(R(i)*(y(:,i)-1)+3*(2+R(i))*(1./y(:,i)-1));
end
figure(1),plot(25.68*fii,X,'linewidth',2)
set(gca,'linewidth',2,'fontsize',14)
xlabel('\Delta\phi (mV)'),ylabel('\chi')