代码：
Clear["all"]
\[Beta] = (j Pi)/180;
e = 1.63*10^-19;
\[CurlyEpsilon]0 = 1.0;
\[CurlyEpsilon]d = 2.0;
\[Mu]d = 1.0;
\[Mu]g = 1.0;
tg = 5*10^-10;
td = 5*10^-8;
t = 300;
\[Tau] = 1*10^-12;
EF = 1.92*10^-19;
h = 1.05*10^-34;
KB = 1.4*10^-23;
\[Sigma] = ((I e^2 KB t)/(Pi h^2 (\[Omega] + I/\[Tau])))[
EF/(KB t) + 2 Log10[1 + E^(-(EF/(KB t)))]] + (I e^2)/(4 \[Pi] h^2)
Log10[Abs[(2 EF - h (\[Omega] + I/\[Tau]))/(
2 EF + h (\[Omega] + I/\[Tau]))]];(*复数*)
Q = Re[\[Sigma]];
\[CurlyEpsilon]g = 1 + (I \[Sigma])/(\[Omega] \[CurlyEpsilon]0 tg);
W = Re[\[CurlyEpsilon]g];
\[CurlyEpsilon]p = \[CurlyEpsilon]g;
\[CurlyEpsilon]x = 2.0;
\[CurlyEpsilon]y = \[CurlyEpsilon]g;
\[CurlyEpsilon]z = \[CurlyEpsilon]g;
\[Mu]x = 1;
\[Mu]y = 1;
\[Mu]z = 1;
\[Beta] = 30 \[Degree];
rsp = ((Sqrt[\[CurlyEpsilon]x]*Sqrt[\[CurlyEpsilon]y] -
Sqrt[\[CurlyEpsilon]x]*Sqrt[\[Mu]y])*
Sin[2 \[Beta]])/((Sqrt[\[CurlyEpsilon]y] +
Sqrt[\[Mu]x])*(Sqrt[\[CurlyEpsilon]x] + Sqrt[\[Mu]y]));
rss = (Sqrt[\[Mu]x]*Sqrt[\[Mu]y] -
Sqrt[\[CurlyEpsilon]x]*
Sqrt[\[CurlyEpsilon]y] + (Sqrt[\[CurlyEpsilon]x]*Sqrt[\[Mu]x] -
Sqrt[\[CurlyEpsilon]y]*Sqrt[\[Mu]y])*
Cos[2 \[Beta]])/((Sqrt[\[CurlyEpsilon]y] +
Sqrt[\[Mu]x])*(Sqrt[\[CurlyEpsilon]x] + Sqrt[\[Mu]y]));
PCR = ((Sqrt[\[CurlyEpsilon]y]*Sqrt[\[Mu]y] -
Sqrt[\[CurlyEpsilon]x]*Sqrt[\[Mu]x])^2 Sin[2 \[Beta]]*
Sin[2 \[Beta]])/((Sqrt[\[CurlyEpsilon]y]*Sqrt[\[Mu]y] -
Sqrt[\[CurlyEpsilon]x]*Sqrt[\[Mu]x])^2 + (Sqrt[\[Mu]x]*
Sqrt[\[Mu]y] -
Sqrt[\[CurlyEpsilon]x]*Sqrt[\[CurlyEpsilon]y])^2 -
2 (Sqrt[\[CurlyEpsilon]y]*Sqrt[\[Mu]y] -
Sqrt[\[CurlyEpsilon]x]*Sqrt[\[Mu]x])*(Sqrt[\[Mu]x]*
Sqrt[\[Mu]y] -
Sqrt[\[CurlyEpsilon]x]*Sqrt[\[CurlyEpsilon]y])*Cos[2 \[Beta]]);
A = rss*rss;
B = Abs[rss];
Plot[A, {\[Omega], 1*10^11, 100*10^11}, PlotRange -> All]

首先，clear那句意义不明，参考 https://tieba.baidu.com/p/7525919546
然后，sigma那句的中括号是什么意思？