O-PTIR reveals the thermal evolution mechanism of ultra-deep light oil: Based on molecular structure and chemical composition analysis - Ruilin Wang; Jiakai Hou; Ting Wang; Yang Sun; Ziguang Zhu; Zhigang Wen; Yanqing Zhu; Zhiyao Zhang; Yaling Zhu; Guangyou Zhu (Chemical Engineering Journal, 2025)