摘要
It has been more than a year since Don left us.He left us so suddenly.We planned to have a phone call after he settled down at his new house.However,it never happened.Although he had some medical issues persistently in his last year,he had been so dedicated to science that he kept working on multiple papers about Earth’s deep interior.Our unfinished paper is about to provide an alternative explanation of the anomalous SPdKS+SKPdS,which has been routinely used to image the Ultralow Velocity Zone(ULVZ).I am so grateful to Don that he brought me into the deep Earth,taught me how to read seismograms,and always inspired and supported me as my family.
