No abstract

Last but not least, I would like to thank my family for their continuous support and encouragement. I own much to my parents who provided great support and understanding even though they were in a difficult time. This thesis would not have been possible without their helps.

No abstract

whom I would like to give many thanks for the guidance, patience, and assistance given to me throughout my doctoral studies. I would also like to express my thanks to my other committee members, Drs. W. Robert Stephenson, Jeramy Ashlock, and Kejin Wang, for their guidance and support throughout my studies, research, and dissertation. Many colleagues and friends have provided me helps with lab tests and field trips. I would like to recognize their efforts and express my appreciation to