Submitted on: 02 February 2017.
Revised on: 30 May 2017.
Accepted on: 13 June 2017.
___________________CURRENT APPLIED PHYSICS---ELSEVIER
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Submitted on: 18 March 2010.
Revised on: 19 June 2010.
Accepted on: 08 August 2010.
___________________CURRENT APPLIED PHYSICS---ELSEVIER
Submitted on: 07 July 2005.
Revised on: 18 September 2005.
Accepted on: 23 October 2005.
___________________CURRENT APPLIED PHYSICS---ELSEVIER
Submitted on: 04 February 2010.
Revised on: 21 March 2010.
Accepted on: 20 April 2010.
___________________CURRENT APPLIED PHYSICS---ELSEVIER
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Submitted on: 13 April 2005.
Revised on: 29 July 2005.
Accepted on: 08 September 2005.
___________________CURRENT APPLIED PHYSICS---ELSEVIER
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Submitted on: 31 July 2015.
Revised on: 24 November 2015.
Accepted on: 13 January 2016.
___________________CURRENT APPLIED PHYSICS---ELSEVIER
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