problems with char(XX) when XX is larger than 127

Hello, there. I've encountered the following problem.

As I typed in char(120:180), I got a lot of ? marks like this:

>> char(120:180)

ans =

xyz{|}~?????????????????????????????????????¤??§¨???????°±???

There is no problem for my MATLAB to recognize characters smaller than 127, however, it just can't recognize other characters?

Also, my PC system's default language is Chinese, when I'm writing to an Excel file with some Chinese characters in it, there is no problem. BUT, when I'm sending an email with an Excel attachment that has an Chinese character name, the file name just become a bunch of garbled characters. Like this:

Title of the email and the message displays Chinese characters alright, just the name of the attachments is messed up encoding. I guess these two problems are related, please help, thanks.