Visa fee for a Canadian university Professor applying for a visa to conduct research in China?

I am a Canadian university Professor applying for a visa (single entry) to conduct research in China, at the invitation of Sun-Yatsen University in Guangzhou. I find conflicting information on the Internet about the visa fee.
1. Can you direct me to the Web site that will give me clear and correct information, or tell me what is the fee that I must pay for the visa?
2. Can I pay for the visa through the Internet?