When highwall mining technology is applied to recover large amounts of residual coal left under the highwall of a big openpit mine,a reasonable coal pillar width is required to ensure the stability of the web pillars....When highwall mining technology is applied to recover large amounts of residual coal left under the highwall of a big openpit mine,a reasonable coal pillar width is required to ensure the stability of the web pillars.Using numerical simulations,this paper studied the characteristics of the abutment stress distribution in the web pillars under different slope angles and mining depths,and established a relation describing the stress distribution in the web pillar.The relationship between the abutment stress and the ultimate strength of the web pillar under different pillar widths was also analyzed.In combination with the failure characteristics of the pillar yield zone,this relationship was used to explore the instability mechanism of web pillars.Finally,the optimal retaining widths of the web pillars were determined.Based on the modeling results,a mechanical bearing model of the web pillar was established and a cusp catastrophe model of pillar-overburden was constructed.Additionally,the web pillar instability criterion was derived.By analyzing the ultimate strength of the web pillars,a formula for calculating the yield zone width either side of the pillars was established.Using the instability criterion of web pillars in highwall mining,a reasonable pillar width can be deduced theoretically,providing significant guidance on the application of highwall mining technology.展开更多
Our study achieves efficient electrocatalysis for the electrooxidation reaction in multi-electrolyte systems by synergistically modulating structure and electronic coupling through rational design.We establish novel p...Our study achieves efficient electrocatalysis for the electrooxidation reaction in multi-electrolyte systems by synergistically modulating structure and electronic coupling through rational design.We establish novel principles for controlling the morphology and performance of metal-organic frameworks(MOFs):Formation of nano-flower structure requires co-existence of Ni site and Fc ligand,doping of Fe sites promotes three-dimensional(3D)crystal morphology development,which marks a pioneering advance in the field.Among them,the bimetallic dual-ligand MOF:NiFe-BDC/Fc(NFBF)(6:2)exhibits outstanding electrocatalytic performance(210 mV at 10 mA·cm^(−2)).Operando Raman spectroscopy and X-ray absorption fine structure(XAFS)reveal the electronic restructuring feature of NFBF(6:2)during the catalytic oxygen evolution reaction(OER)process.Combined with density functional theory(DFT)calculations,which identify Ni as the catalytic active site,these investigations uncover significant electronic migration and redistribution,substantially reducing the reaction energy barrier and accelerating the catalytic process.Comprehensive exploration demonstrates that NFBF(6:2)not only performs well under various multi-electrolyte conditions but also maintains a nearly consistent catalytic mechanism.Furthermore,when applied to overall water splitting,(+)NFBF(6:2)||NFBF(6:2)(−)achieves significant catalytic effects in both alkaline freshwater(1.40 V at 10 mA·cm^(−2))and seawater(1.44 V at 10 mA·cm^(−2))electrolyzers.This work highlights the crucial role of electronic coupling in optimizing electrocatalytic performance and offers new insights for addressing mitigating environmental pollution,embodying substantial practical and research potential.展开更多
基金This project was supported by the National Natural Science Foundation of China under Project No.51874160,LNTU20TD-01the“Millions of Talents Project”of Liaoning Province China.
文摘When highwall mining technology is applied to recover large amounts of residual coal left under the highwall of a big openpit mine,a reasonable coal pillar width is required to ensure the stability of the web pillars.Using numerical simulations,this paper studied the characteristics of the abutment stress distribution in the web pillars under different slope angles and mining depths,and established a relation describing the stress distribution in the web pillar.The relationship between the abutment stress and the ultimate strength of the web pillar under different pillar widths was also analyzed.In combination with the failure characteristics of the pillar yield zone,this relationship was used to explore the instability mechanism of web pillars.Finally,the optimal retaining widths of the web pillars were determined.Based on the modeling results,a mechanical bearing model of the web pillar was established and a cusp catastrophe model of pillar-overburden was constructed.Additionally,the web pillar instability criterion was derived.By analyzing the ultimate strength of the web pillars,a formula for calculating the yield zone width either side of the pillars was established.Using the instability criterion of web pillars in highwall mining,a reasonable pillar width can be deduced theoretically,providing significant guidance on the application of highwall mining technology.
基金support from the National Natural Science Foundation of China(No.21401151)Fundamental Research Funds for the Central Universities(No.2682023ZTPY064)Sichuan Provincial Administration of Traditional Chinese Medicine Project(No.2023MS212).
文摘Our study achieves efficient electrocatalysis for the electrooxidation reaction in multi-electrolyte systems by synergistically modulating structure and electronic coupling through rational design.We establish novel principles for controlling the morphology and performance of metal-organic frameworks(MOFs):Formation of nano-flower structure requires co-existence of Ni site and Fc ligand,doping of Fe sites promotes three-dimensional(3D)crystal morphology development,which marks a pioneering advance in the field.Among them,the bimetallic dual-ligand MOF:NiFe-BDC/Fc(NFBF)(6:2)exhibits outstanding electrocatalytic performance(210 mV at 10 mA·cm^(−2)).Operando Raman spectroscopy and X-ray absorption fine structure(XAFS)reveal the electronic restructuring feature of NFBF(6:2)during the catalytic oxygen evolution reaction(OER)process.Combined with density functional theory(DFT)calculations,which identify Ni as the catalytic active site,these investigations uncover significant electronic migration and redistribution,substantially reducing the reaction energy barrier and accelerating the catalytic process.Comprehensive exploration demonstrates that NFBF(6:2)not only performs well under various multi-electrolyte conditions but also maintains a nearly consistent catalytic mechanism.Furthermore,when applied to overall water splitting,(+)NFBF(6:2)||NFBF(6:2)(−)achieves significant catalytic effects in both alkaline freshwater(1.40 V at 10 mA·cm^(−2))and seawater(1.44 V at 10 mA·cm^(−2))electrolyzers.This work highlights the crucial role of electronic coupling in optimizing electrocatalytic performance and offers new insights for addressing mitigating environmental pollution,embodying substantial practical and research potential.
