1. Key Laboratory of Special Functional and Smart Polymer Materials of Ministry of Industry and Information Technology Xi'an Key Laboratory of Functional Organic Porous Materials School of Chemistry and Chemical Engineering Northwestern Polytechnical University Xi'an Shaanxi 710072 P. R. China
2. Department of Chemistry University of South Florida 4202 East Fowler Avenue, CHE205 Tampa FL 33620-5250 USA
3. School of Aeronautics Northwestern Polytechnical University Xi' an Shaanxi 710072 P. R. China