Submitted on: 24 December 1998.
Revised on: 27 March 1999.
Accepted on: 16 April 1999.
___________________European Physical Journal H---SPRINGER HEIDELBERG
http://reply.papertrans.cn/1/94/9356/9356-32.png
Submitted on: 08 February 2016.
Revised on: 08 May 2016.
Accepted on: 19 May 2016.
___________________European Physical Journal H---SPRINGER HEIDELBERG
Submitted on: 06 June 2017.
Revised on: 31 August 2017.
Accepted on: 10 October 2017.
___________________European Physical Journal H---SPRINGER HEIDELBERG
http://reply.papertrans.cn/1/94/9356/9356-35.png
Submitted on: 29 September 2018.
Revised on: 31 December 2018.
Accepted on: 17 February 2019.
___________________European Physical Journal H---SPRINGER HEIDELBERG