US-China tax treaty for J1-professor residence alien

I am a Chinese national and hold a J1-professor visa in US. Before that I was in US as F1-student for 6 years and so became a resident alien for tax purposes.

I wonder if I am still eligible for the US-China tax treaty under Article 19?

If so, how can I claim that when file tax withholdings or when file tax returns?

Thanks for your help!