http://reply.papertrans.cn/3/247/24638/24638-21.png
http://reply.papertrans.cn/3/247/24638/24638-22.png
http://reply.papertrans.cn/3/247/24638/24638-23.png
http://reply.papertrans.cn/3/247/24638/24638-24.png
http://reply.papertrans.cn/3/247/24638/24638-25.png
http://reply.papertrans.cn/3/247/24638/24638-26.png
http://reply.papertrans.cn/3/247/24638/24638-27.png
Submitted on: 09 December 2004.
Revised on: 05 January 2005.
Accepted on: 22 January 2005.
Physical Review Physics Education Research
Submitted on: 17 May 2004.
Revised on: 26 May 2004.
Accepted on: 20 June 2004.
Physical Review Physics Education Research
Submitted on: 08 February 2017.
Revised on: 13 March 2017.
Accepted on: 28 March 2017.
Physical Review Physics Education Research