1. Department of Mathematics and Statistics, University of Strathclyde, Livingstone Tower, 26 Richmond Street, Glasgow G1 1XH, United Kingdom
2. School of Engineering, University of Edinburgh, The King’s Buildings, Mayfield Road, Edinburgh EH9 3JL, United Kingdom
3. Tianjin Key Laboratory of Refrigeration Technology, Tianjin University of Commerce, Tianjin 300134, China