[2] Xiaoxiao Wang, Yingchun Wang, Yongbing Xue. Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 39, 1(2017).

[3] Rita Khanna, Kejiang Li, Jianliang Zhang et al. Energy & Fuels, 29, 7178(2015).

[8] C Painter P, W Snyder R, M Starsinic et al. Applied Spectroscopy, 35, 475(1981).

[9] M Garangelo R, R Solomon P. Fuel, 61, 663(1982).

[10] R Bassilakis, M Carangelo R, A Wójtowicz M. Fuel, 80, 1765(2001).

[11] M Fredericks P. Coal Science and Technology, 41, 327(1987).

[12] V Ibarra J, R Moliner, E Munoz. Organic Geochemistry, 24, 725(1996).

[13] W Geng, T Nakajima, H Takanashi et al. Fuel, 88, 139(2009).

[14] Yanyan Chen, M Mastalerz, A Schimmelmann. International Journal of Coal Geology, 104, 22(2012).

[15] A Painter P, M Sobkowiak. Energy and Fuels, 9, 359(1995).

[16] D Glasser, G Glover, J Walt T et al. Fuel, 74, 1216(1995).

[17] C Coin, H Kahraman, J Thomasson et al. Fuel, 79, 685(2000).

[18] G Liu, R Sun, D Wu et al. Energy Fuels, 27, 23(2013).

[19] G Liu, H Song, J Zhang et al. Fuel Process Technol., 156, 454(2017).

[20] R Cabanzo, E Mejía-Ospino, A Orrego-Ruiz J. International Journal of Coal Geology, 85, 307(2011).

[21] D Behera, S Bhattacharya, K Nandi B. International Journal of Coal Preparation and Utilization, 1(2020).

[22] Hongyi Wei, Hongru Zhao, Hongqing Zhu et al. Combustion and Flame, 216, 354(2020).

[23] Zhenhua Jing, S Rodrigues, E Strounina et al. International Journal of Coal Geology, 201, 1(2018).

[24] D Green P, A Johnson C, M Thomas K. Fuel, 62, 1013(1983).

[25] J Chem, L Koenig J, F Tuinstra. Phys., 53, 1129(1970).

[26] L Carlson G, A Friedel R. Fuel, 51, 194(1971).

[27] A Johnson C, W Patrick J, M Thomas K. Fuel, 65, 1284(1986).

[28] A Johnson C, M Thomas K. Fuel, 66, 17(1987).

[29] H Dou, J Kister. Fuel Process Technology, 12, 19(1986).

[30] L Bonal, E Quirico, N Rouzaud J et al. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 61, 2368(2005).

[31] C Ferrari A, J Robertson. Physical Review B, 61, 14095(2000).

[32] D Dietrich, K Nestler, K Witke et al. Journal of Molecular Structure, 661-662, 357(2003).

[33] D Flores, M Marques, I Suarez-Ruiz et al. International Journal of Coal Geology, 77, 377(2009).

[34] T Brown M, R Hinrichs, M A Z Vasconcellos et al. International Journal of Coal Geology, 136, 52(2014).

[35] N Maledi, S Potgieter-Vermaak, N Wagner et al. Journal of Raman spectroscopy, 42, 123(2009).

[36] Jiawei Liu, Jun Xiang, Jun Xu et al. Proceedings of the Combustion Institute, 37, 3053(2019).

[37] M Havelcová, V Machovič, I Sykorová et al. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 246, 1(2020).

[38] Jianzhi Hu, S Solum M, C M V Taylor et al. Energy & Fuels, 15, 14(2001).

[39] W Michael A, P Ronald J. Trends in Analytical Chemistry, 3, 144(1984).

[40] J Pugmire R, F Sarofim A, S Solum M et al. Energy & Fuels, 15, 961(2001).

[41] K Gordon J, M Kanmi, A Stacey M et al. Energy & Fuels, 26, 4405(2012).

[42] H Mroue K, A Ramamoorthy, C Zhang R. Journal of Magnetic Resonance, 266, 59(2016).

[43] C Ciavatta, O Francioso, D Montecchio et al. Bioresource Technology, 88, 189(2003).

[44] E Maciel G, Jincheng Xiong. Energy & Fuels, 16, 791(2002).

[45] W Dickinson W, P Suggate R. International Journal of Coal Geology, 57, 1(2004).

[46] Jiaxun Liu, Lei Luo, Junfang Ma et al. Energy & Fuels, 30, 6321(2016).

[47] Shimin Liu, Yingfeng Sun, Yixin Zhao et al. Fuel, 190, 359(2017).

[48] Y Hata, K Okushita, Y Sugimoto et al. Energy & Fuels, 33, 1(2019).