\documentclass[12pt,a4paper]{article}
\usepackage{CJKutf8}
\usepackage[utf8]{inputenc} % R Sweave needs this
\usepackage{Sweave}
\begin{document}
\setkeys{Gin}{width=1.0\textwidth}

<<echo=FALSE>>=
cairo <- function(name, width, height, ...)
  grDevices::cairo_pdf(file = paste(name, "pdf", sep = "."),
                          width = width, height = height)
@

<<fig=TRUE,pdf=FALSE,grdevice=cairo>>=
plot(c(0,1),c(0,1),xlab='',ylab='', main="雜合性基因調用率X性染色體")
@
\end{document}
