$@3%?'Bg5$$N>l9g5[<}78?t$OGHD9$K$h$i$J$$$N$G(B, $@J|<MB+L)EY$K4X$9$kEAC#J}Dx<0(B
\Deqref{eq: 2.5}, \Deqref{eq: 2.6}$@$OGHD9$K$D$$$F4JC1$K@QJ,$9$k$3$H$,$G$-$k(B.
\Deqref{eq: 2.5}, \Deqref{eq: 2.6}$@$rA4GHD9$G@QJ,$7$F(B,
\begin{eqnarray}
 \frac{2}{3}\DD{F^{\uparrow }}{\tau }
&=& F^{\uparrow }-\pi B \Deqlab{eq: 2.9} \\
 \frac{2}{3}\DD{F^{\downarrow }}{\tau }
&=& -F^{\downarrow }+\pi B\Deqlab{eq: 2.10}
\end{eqnarray}
$@$rF@$k(B.
$@$?$@$7(B, 
\begin{eqnarray}
 F^{\uparrow }&=& \int _{0}^{\infty }F_{\nu }^{\uparrow }\Dd \nu
\Deqlab{eq: 2.11} \\
 F^{\downarrow }&=& \int _{0}^{\infty }F_{\nu }^{\downarrow }\Dd \nu
\Deqlab{eq: 2.12}
\end{eqnarray}
$@$OGHD9@QJ,$5$l$?J|<MB+L)EY$G$"$j(B, $B=\sigma T^{4}/\pi $ $@$G$"$k(B.
$@2r$O(B, 
\begin{eqnarray}
 F^{\uparrow }(\tau )&=&F^{\uparrow }(\tau _{b})e^{\frac{3}{2}
(\tau -\tau _{b})}+\int _{\tau }^{\tau _{b}}\frac{3}{2}\pi 
Be^{-\frac{3}{2}(\tau '-\tau )}\Dd \tau ' \Deqlab{eq: 2.13} \\
 F^{\downarrow }(\tau )&=&F^{\downarrow }(0)e^{-\frac{3}{2}\tau }+
\int _{0}^{\tau }\frac{3}{2}\pi Be^{\frac{3}{2}(\tau '-\tau )}
\Dd \tau ' \Deqlab{eq: 2.14}
\end{eqnarray}
$@$^$?$O@QJ,ItJ,$r=q$-D>$7$F(B,
\begin{eqnarray}
 F^{\uparrow }(\tau )&=&(F^{\uparrow }(\tau _{b})-\pi B(\tau _{b}))
e^{\frac{3}{2}(\tau -\tau _{b})}+\pi B(\tau )+\int _{\tau }^{\tau _{b}}
\DD{\pi B(\tau ')}{\tau '}e^{-\frac{3}{2}(\tau '-\tau )}\Dd \tau ' 
\Deqlab{eq: 2.15} \\
 F^{\downarrow }(\tau )&=&(F^{\downarrow }(0)-\pi B(0))e^{-\frac{3}{2}\tau }+
\pi B(\tau )-\int _{0}^{\tau }\DD{\pi B(\tau )}{\tau '}e^{\frac{3}{2}
(\tau '-\tau )}\Dd \tau ' \Deqlab{eq: 2.16}
\end{eqnarray}
$@$H$J$k(B.

$@$5$FJ|<M8;$H$7$FCOI=$+$i$N@V30J|<M$N$_$r9M$($k>l9g(B, $@Bg5$>eC<$G$N(B
$@2<8~$-J|<MB+L)EY$O(B0, $@Bg5$2<C<$G$N>e8~$-J|<MB+L)EY$O(B $\pi B(\tau _{b})$ $@$K(B
$@Ey$7$$$N$G(B, \Deqref{eq: 2.15}, \Deqref{eq: 2.16}$@$O0J2<$N$h$&$K$J$k(B.
\begin{eqnarray}
 F^{\uparrow }(\tau )&=&\pi B(\tau )+\int _{\tau }^{\tau _{b}}
\DD{\pi B(\tau ')}{\tau '}e^{-\frac{3}{2}(\tau '-\tau )}\Dd \tau ' 
\Deqlab{eq: 2.17} \\
 F^{\downarrow }(\tau )&=&\pi B(\tau )-\pi B(0)e^{-\frac{3}{2}\tau }-
\int _{0}^{\tau }\DD{\pi B(\tau )}{\tau '}e^{\frac{3}{2}
(\tau '-\tau )}\Dd \tau ' \Deqlab{eq: 2.18}
\end{eqnarray}


