{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,8]],"date-time":"2026-09-08T05:10:06Z","timestamp":1788844206969,"version":"build-2803163510"},"reference-count":32,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2026,9,4]],"date-time":"2026-09-04T00:00:00Z","timestamp":1788480000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Open Fund of the State Key Laboratory of Intelligent Mining Equipment Technology","award":["ZNCKKF20240108"],"award-info":[{"award-number":["ZNCKKF20240108"]}]},{"name":"Excellent Young Talents Fund of Higher Education Institutions of Anhui Province","award":["2024AH030006"],"award-info":[{"award-number":["2024AH030006"]}]},{"name":"Open Fund of the State Key Laboratory of Digital Intelligent Technology for Unmanned Coal Mining","award":["SKLMRDPC22KF22"],"award-info":[{"award-number":["SKLMRDPC22KF22"]}]},{"name":"Key Project for Natural Science Research of Universities in Anhui Province","award":["2024AH052008"],"award-info":[{"award-number":["2024AH052008"]}]},{"name":"Natural Science Key Research Project of Wuhu Institute of Technology","award":["wzyzrzd202504"],"award-info":[{"award-number":["wzyzrzd202504"]}]},{"award":["wzyzrzd202504"],"award-info":[{"award-number":["wzyzrzd202504"]}],"id":[{"id":"https:\/\/ror.org\/055hnk386","id-type":"ROR","asserted-by":"publisher"}]},{"name":"Key Project of the Educational Research and Planning Program of the Anhui Provincial Association for Vocational and Adult Education","award":["AZCJ2025089"],"award-info":[{"award-number":["AZCJ2025089"]}]},{"name":"Open Research Fund of Anhui Provincial Key Laboratory of Advanced Detection and Intelligent Sensing","award":["JCKJ2025A08 and JCKJ2025A010"],"award-info":[{"award-number":["JCKJ2025A08 and JCKJ2025A010"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>Quantitative determination of gangue content is important for efficient coal use and intelligent coal\u2013gangue separation. We combine transmission terahertz time-domain spectroscopy (THz-TDS), multidomain feature fusion, and machine learning to predict gangue mass fraction in coal\u2013gangue mixtures. Time- and frequency-domain signals, refractive index, absorption and extinction coefficients, and complex permittivity were extracted from samples with different gangue contents. Five-fold cross-validation was used to compare random forest, support vector regression, Gaussian process regression, an artificial neural network, and an Effective Medium Theory-constrained Physics-Informed Neural Network (EMT-PINN). EMT-PINN achieved the best performance, with a coefficient of determination (R2) of 0.81 \u00b1 0.15, a mean absolute error (MAE) 3.17 \u00b1 0.59%, and a root mean square error (RMSE) of 5.79 \u00b1 0.21%, compared with R2 values of 0.72 \u00b1 0.08, 0.61 \u00b1 0.21, 0.74 \u00b1 0.11, and 0.64 \u00b1 0.18 for RF, SVR, GPR, and ANN, respectively. These results demonstrate the potential of physics-informed THz spectroscopy for rapid and physically interpretable quantitative characterization of coal\u2013gangue mixtures.<\/jats:p>","DOI":"10.3390\/ma19173776","type":"journal-article","created":{"date-parts":[[2026,9,4]],"date-time":"2026-09-04T16:07:32Z","timestamp":1788538052000},"page":"3776","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Quantitative Prediction of Coal\u2013Gangue Content Using Terahertz Time-Domain Spectroscopy and Physics-Informed Machine Learning"],"prefix":"10.3390","volume":"19","author":[{"given":"Zeping","family":"Liu","sequence":"first","affiliation":[{"name":"State Key Laboratory of Intelligent Mining Equipment Technology, Taiyuan 030032, China"},{"name":"Shanxi TZCO Intelligent Mining Equipment Technology Co., Ltd., Taiyuan 030032, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lipeng","family":"Hu","sequence":"additional","affiliation":[{"name":"School of Artificial Intelligence, Anhui Polytechnic University, Wuhu 241000, China"},{"name":"Key Laboratory of Pressure System and Safety, Ministry of Education, School of Mechanical and Power Engineering, East China University of Science and Technology, No. 130 Meilong Road, Shanghai 200237, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jianfei","family":"Xu","sequence":"additional","affiliation":[{"name":"School of Intelligent Manufacturing, Wuhu University, Wuhu 241008, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yadong","family":"Yang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Intelligent Mining Equipment Technology, Taiyuan 030032, China"},{"name":"Shanxi TZCO Intelligent Mining Equipment Technology Co., Ltd., Taiyuan 030032, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sitong","family":"Li","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Intelligent Mining Equipment Technology, Taiyuan 030032, China"},{"name":"Shanxi TZCO Intelligent Mining Equipment Technology Co., Ltd., Taiyuan 030032, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zhou","family":"Xu","sequence":"additional","affiliation":[{"name":"School of Electrical and Automation, Wuhu Vocational Technical University, Wuhu 241006, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Longhai","family":"Liu","sequence":"additional","affiliation":[{"name":"Key Laboratory of Opto-Electronics Information Technology, Ministry of Education, School of Precision Instruments and Opto-Electronics Engineering, Tianjin University, Tianjin 300072, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0004-6761-7010","authenticated-orcid":false,"given":"Jiabao","family":"Li","sequence":"additional","affiliation":[{"name":"School of Artificial Intelligence, Anhui Polytechnic University, Wuhu 241000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Houli","family":"Liu","sequence":"additional","affiliation":[{"name":"School of Artificial Intelligence, Anhui Polytechnic University, Wuhu 241000, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dongdong","family":"Ye","sequence":"additional","affiliation":[{"name":"School of Artificial Intelligence, Anhui Polytechnic University, Wuhu 241000, China"},{"name":"Key Laboratory of Pressure System and Safety, Ministry of Education, School of Mechanical and Power Engineering, East China University of Science and Technology, No. 130 Meilong Road, Shanghai 200237, China"},{"name":"Aviation Industry Corporation Huadong Photoelectric Co., Ltd., Wuhu 241003, China"},{"name":"State Key Laboratory of Digital Intelligent Technology for Unmanned Coal Mining, Anhui University of Science and Technology, Huainan 232001, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,4]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1834","DOI":"10.1016\/j.scib.2025.03.035","article-title":"Incorporating site suitability and carbon sequestration of tree species into China\u2019s climate-adaptive forestation","volume":"70","author":"Zhang","year":"2025","journal-title":"Sci. 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