jupyter notebook with unicode characters PDF converting problems - unicode

Question

I was making a math class note with some unicode characters (Simplified Chinese, in my case) in it. And when I was trying to convert it into PDF file, it popped out 500 error. The error message reads:
...
*************************************************
("E:\Program Files (x86)\MiKTeX 2.9\tex\latex\fontspec\fontspec.sty"
("E:\Program Files (x86)\MiKTeX 2.9\tex\latex\fontspec\fontspec-xetex.sty"
("E:\Program Files (x86)\MiKTeX 2.9\tex\latex\base\fontenc.sty"
("E:\Program Files (x86)\MiKTeX 2.9\tex\latex\base\tuenc.def"))
("E:\Program Files (x86)\MiKTeX 2.9\tex\latex\fontspec\fontspec.cfg")
! Undefined control sequence.
<argument> \LaTeX3 error:
Erroneous variable \c__fontspec_shape_n_n_tl used!
l.3806 \emfontdeclare{ \emshape, \eminnershape }
?
! Emergency stop.
<argument> \LaTeX3 error:
Erroneous variable \c__fontspec_shape_n_n_tl used!
l.3806 \emfontdeclare{ \emshape, \eminnershape }
No pages of output.
Transcript written on notebook.log.
I guess the fontspec part went wrong, but I don't know how to solve it.
For your information, here is what I've done before I got the 500 error.
1.I've installed the pandoc, and I already have Miktex before;
2.I've changed the file
...\nbconvert\templates\latex\article.tplx
rewritten the article class to be ctexart;
3.I've changed the file
...\nbconvert\templates\latex\exporters\pdf.py
rewritten the latex command to be
latex_command = List([u"xelatex", u"{filename}"], config=True,
help="Shell command used to compile latex."
)
4.I've also tried this:"https://github.com/ipython/ipython/issues/7150", which tends to convert the ipynb file into latex file first, then into PDF. And this didn't work for me either. The main reason is that the config file can't be found by jupyter nbconvert command.
For your information, my OS is Win7 Ultimate x64, with Chrome for Anaconda3 jupyter notebook.
Thanks in advance for anyone who takes time to read my post. Any help would be appreciated.