On Mar. 3, being invited by innovation team of “Financing Innovation and Rural Development”, Mr. Wang Chenggang (lifetime professor of Texas Tech University and Texas A&M University, made a report themed “External Problems existed in Resource and Environment Economics”. 　
　　The academic exchange was hosted by Lv Kaiyu, Xia Ying and Liu Jing (both are researchers of IEAD), Xue Li (deputy researcher of IEAD) and other 20 teachers and students joined this academic exchange. On the meeting, Professor Wang Chenggang, taking resources and environment as examples, made a systematic analysis on the external problems existed in economics. First, he proposed the concepts of pecuniary externalities, technological externalities, priviate externalities and public externalities; second, he did a welfare analysis and policy simulation for the externalities; third, combining with the reasons why there are externalities and the policy connotation, he analyzed the policies related to fairness and efficiency of externalities. After the report, IEAD researchers, the students and Professor Wang had a deep discussion. On the meeting, there is a strong and friendly atmosphere of academics. 　　　
　　Professor Wang Chenggang is the lifetime professor in Texas Tech University (75%) and Texas A&M University (25%). Now, Professor Wang is having a cooperation with Lv Kaiyu to study the agriculture and land systems, agricultural investment and land fertility in China. What they are working on was greatly supported by NSFC(Natural Science Foundation of China) （71573262.