国家自然科学基金30870006;国家海洋可再生能源专项基金SDME2011SW01;国家"863计划"2012AA10180402.Supported by the National Natural Science Foundation of China30870006;by the Chinese Marine Renewable Energy Special FoundationSDME2011SW01;by the National Programs for High Technology Research and Development of China2012AA10180402