This paper focuses on the use of rotary-percussive drilling for hard rocks.In order to improve efficiency and reduce costs,it is essential to understand how operational parameters,bit wear,and drilling performance are...This paper focuses on the use of rotary-percussive drilling for hard rocks.In order to improve efficiency and reduce costs,it is essential to understand how operational parameters,bit wear,and drilling performance are related.A model is presented therein that combines multibody dynamics and discrete element method(DEM)to investigate the influences of operational parameters and bit wear on the rate of penetration and wear characteristics.The model accurately captures the motion of the bit and recreates rock using the cutting sieving result.Field experimental results validate the rod dynamic behavior,rock recreating model,and coupling model in the simulation.The findings indicate that hammer pressure significantly influences the rate of penetration and wear depth of the bit,and there is an optimal range for economical hammer pressure.The wear coefficient has a major effect on the rate of penetration,when wear coefficient is between 1/3 and 2/3.Increasing the wear coefficient can reduce drill bit button pressure and wear depth at the same drill distance.Gauge button loss increases the rate of penetration due to higher pressure on the remaining buttons,which also accelerates destruction of the bit.Furthermore,a more evenly distributed button on the bit enhances the rate of penetration(ROP)when the same number of buttons is lost.展开更多
Hierarchical lignin-derived ordered mesoporous carbon(HOMC)was significant for advanced supercapacitors.However,achieving controllable fabrication and optimizing electrochemical behavior were challenging.In this work,...Hierarchical lignin-derived ordered mesoporous carbon(HOMC)was significant for advanced supercapacitors.However,achieving controllable fabrication and optimizing electrochemical behavior were challenging.In this work,an eco-friendly HOMC was synthesized using lignin as carbon precursors and Zn^(2+)as cross-linking and pore-forming agents,followed by KHCO_(3)activation,eliminating the need for toxic phenolic resins and acid treatments for metal removal.Machine learning technology,specifically an Artificial Neural Network(ANN model,was utilized to assist the experimental design and prediction.The ANN model suggested an ideal hierarchical structure and optimized oxygen level,achieved through the adjustment of Zn^(2+)additive concentration,carbonization temperature,and subsequent KHCO_(3)activation to maximize capacitance.The HOMC electrode,with a micropore-to-mesopore ratio(S_(micro)/S_(meso))of 1.01 and an oxygen content of 8.81 at%,acquired a specific capacitance of 362 F·g^(-1)at 0.5 A·g^(-1)in 6 mol·L^(-1)KOH electrolyte.The assembled HOMC//HOMC supercapacitor could afford a high energy density of 33.38 Wh·kg^(-1)with a corresponding specific power density of 300 W·kg^(-1)in TEATFB PC electrolyte.Meanwhile,the long-term cycle stability of 94.33%was achieved after 20,000 cycles.This work provides an ANN assisted strategy for the synthesis of HOMC,highlighting its potential to valorize biomass and agricultural waste in sustainable energy storag solutions.展开更多
Thermal damage mechanisms are crucial in reservoir stimulation for enhanced geothermal system(EGS).This study investigates the thermal damage mechanisms in granite samples from the Gonghe Basin,Qinghai,China.The grani...Thermal damage mechanisms are crucial in reservoir stimulation for enhanced geothermal system(EGS).This study investigates the thermal damage mechanisms in granite samples from the Gonghe Basin,Qinghai,China.The granite samples were heated to 400℃ and then cooled in air,water,or liquid nitrogen.The physical and mechanical properties of the thermally treated granite were evaluated,andmicrostructural changes were analyzed using a scanning electron microscope(SEM)and computed tomography(CT).The results indicate that cooling with water and liquid nitrogen significantly enhancespermeability and brittleness while reducing P-wave velocity,strength,and Young's modulus.Specifically,liquid nitrogen cooling increased granite permeability by a factor of 5.24 compared to the untreatedsamples,while reducing compressive strength by 13.6%.After thermal treatment,the failure mode of thegranite shifted from axial splitting to a combination of shear and tension.Microstructural analysisrevealed that liquid nitrogen-cooled samples exhibited greater fracture complexity than those cooledwith water or air.Additionally,acoustic emission(AE)monitoring during damage evolution showed thatliquid nitrogen cooling led to higher cumulative AE energy and a lower maximum AE energy rate,withnumerous AE signals detected during both stable and unstable crack growth.The results suggest thatliquid nitrogen induces a stronger thermal shock,leading to more significant thermal damage andpromoting the development of a complex fracture network during EGS reservoir stimulation.This enhancesboth the heat exchange area and the permeability of the deep hot dry rock(HDR)in EGS reservoirs.The insights from this study contribute to a deeper understanding of thermal damagecharacteristics induced by different cooling media and provide valuable guidance for optimizing deepgeothermal energy extraction.展开更多
Intraspecific genetic variance and gene flow can support the adaptive evolution of species challenged by climate shifts or novel environmental conditions.Less well understood is how genome organization and gene flow i...Intraspecific genetic variance and gene flow can support the adaptive evolution of species challenged by climate shifts or novel environmental conditions.Less well understood is how genome organization and gene flow interact in closely related species during evolutionary divergence and differentiation.Here we conducted genomic footprint analyses to determine how three species of Pterocarya(P.stenoptera,P.hupehensis,and P.macroptera),which are sympatric but occupy different elevational niches,adapted to the heterogeneous environment of the Qinling-Daba Mountains,China.We identified candidate genes for environmental adaptation(i.e.,PIEZO1,WRKY39,VDAC3,CBL1,and RAF),and also identified regions of gene introgression between P.hupehensis and P.macroptera that show lower genetic load and higher genetic diversity than the rest of their genomes.The same introgressed regions are notably situated in areas of minimal genetic divergence yet they are characterized by elevated recombination rates.We also identified candidate genes within these introgressed regions related to environmental adaptation(TPLC2,CYCH;1,LUH,bHLH112,GLX1,TLP-3,and ABC1).Our findings have thus clarified the important role of gene flow in ecological adaptation and revealed genomic signatures of past introgression.Together,these findings provide a stronger theoretical basis for understanding the ecological adaptation and conservation of Quaternary relict woody plants in East Asia.展开更多
Biocompatible amphiphilic nanoparticles(NPs)with tunable particle morphology and surface property are important for their applications as functional materials.However,previously developed methods to prepare amphiphili...Biocompatible amphiphilic nanoparticles(NPs)with tunable particle morphology and surface property are important for their applications as functional materials.However,previously developed methods to prepare amphiphilic NPs generally involve several steps,especially an additional step for surface modification,greatly hindering their largescale production and widespread applications.Here,a versatile one-step strategy is developed to prepare biocompatible amphiphilic dimer NPs with tunable particle morphology and surface property.The amphiphilic dimer NPs,which consist of a hydrophobic shellac bulb and a hydrophilic poly(lactic acid)(PLA)bulb with PLA-poly(ethylene glycol)(PEG)on the bulb surface,are prepared in a single step by controlled co-precipitation and self-assembly.Amphiphilic PLA-PEG/shellac dimer NPs demonstrate excellent tunability in particle morphology,thus showing good performances in controlling the interfacial curvature and emulsion type.In addition,temperatureresponsive PLA-poly(N-isopropyl acrylamide)(PNIPAM)/shellac dimer NPs are prepared following the same method and emulsions stabilized by them show temperature-triggered response.The applications of PLA-PEG-folic acid(FA)/shellac dimer NPs for drug delivery have also been demonstrated,which show a very good performance.The strategy of preparing the dimer NPs is green,scalable,facile and versatile,which provides a good platform for the design of dimer NPs with tunable particle morphology and surface property for diverse applications.展开更多
China's shale oil and gas resources are widely distributed in shale-sandstone interbedded reservoirs,whose complex lithology and strong heterogeneity pose significant challenges to hydraulic fracturing design.To a...China's shale oil and gas resources are widely distributed in shale-sandstone interbedded reservoirs,whose complex lithology and strong heterogeneity pose significant challenges to hydraulic fracturing design.To address issues such as the difficulty in controlling fracture height and the challenge of forming an effective fracture network,this study utilizes synthetic rock samples that can represent the characteristics of interbedded reservoirs and investigates the initiation and propagation of hydraulic fractures under different viscosity,injection rate,and construction scheme.By combining real-time monitoring of injection pressure with acoustic emission,the temporal and spatial evolution characteristics of hydraulic fractures as well as the mechanisms of their vertical and horizontal extension are revealed.The results indicate that a higher fracturing fluid viscosity is essential for ensuring the vertical cross-layer propagation of hydraulic fractures,while a lower fluid viscosity facilitates the activation of weak interlayer surfaces,promoting sufficient horizontal propagation along these planes and forming branched fractures.Although a higher injection rate enhances the vertical cross-layer propagation of hydraulic fractures,it also causes greater diversion of the main fracture plane,resulting in simpler fracture morphology and limiting the stimulation effect.Additionally,an alternating injection of high and low viscosity fracturing fluids allows hydraulic fractures to both break through weak interlayer surfaces and achieve uniform horizontal propagation,resulting in a more complex fracture morphology.The findings are expected to provide a scientific basis and practical guidance for optimizing hydraulic fracturing designs in interbedded reservoir conditions.展开更多
基金supported by the National Natural Science Foundation of China Youth Science Foundation of China(Grant No.52308388)the Key Project of High-speed Rail Joint Fund of National Natural Science Foundation of China(Grant No.U1934210).
文摘This paper focuses on the use of rotary-percussive drilling for hard rocks.In order to improve efficiency and reduce costs,it is essential to understand how operational parameters,bit wear,and drilling performance are related.A model is presented therein that combines multibody dynamics and discrete element method(DEM)to investigate the influences of operational parameters and bit wear on the rate of penetration and wear characteristics.The model accurately captures the motion of the bit and recreates rock using the cutting sieving result.Field experimental results validate the rod dynamic behavior,rock recreating model,and coupling model in the simulation.The findings indicate that hammer pressure significantly influences the rate of penetration and wear depth of the bit,and there is an optimal range for economical hammer pressure.The wear coefficient has a major effect on the rate of penetration,when wear coefficient is between 1/3 and 2/3.Increasing the wear coefficient can reduce drill bit button pressure and wear depth at the same drill distance.Gauge button loss increases the rate of penetration due to higher pressure on the remaining buttons,which also accelerates destruction of the bit.Furthermore,a more evenly distributed button on the bit enhances the rate of penetration(ROP)when the same number of buttons is lost.
基金supported by National Natural Science Foundation of China(52376104,52201158)Joint Funds of the National Natural Science Foundation of China(U20A20302)+3 种基金Innovative group projects in Hebei Province(E2021202006)the project of Science and Technology in the Universities of Hebei Province(JZX2023006)Natural Science Foundation of Hebei Province(C202202003)Hebei University of Technology Cross-disciplinary(XKJC-2024001)。
文摘Hierarchical lignin-derived ordered mesoporous carbon(HOMC)was significant for advanced supercapacitors.However,achieving controllable fabrication and optimizing electrochemical behavior were challenging.In this work,an eco-friendly HOMC was synthesized using lignin as carbon precursors and Zn^(2+)as cross-linking and pore-forming agents,followed by KHCO_(3)activation,eliminating the need for toxic phenolic resins and acid treatments for metal removal.Machine learning technology,specifically an Artificial Neural Network(ANN model,was utilized to assist the experimental design and prediction.The ANN model suggested an ideal hierarchical structure and optimized oxygen level,achieved through the adjustment of Zn^(2+)additive concentration,carbonization temperature,and subsequent KHCO_(3)activation to maximize capacitance.The HOMC electrode,with a micropore-to-mesopore ratio(S_(micro)/S_(meso))of 1.01 and an oxygen content of 8.81 at%,acquired a specific capacitance of 362 F·g^(-1)at 0.5 A·g^(-1)in 6 mol·L^(-1)KOH electrolyte.The assembled HOMC//HOMC supercapacitor could afford a high energy density of 33.38 Wh·kg^(-1)with a corresponding specific power density of 300 W·kg^(-1)in TEATFB PC electrolyte.Meanwhile,the long-term cycle stability of 94.33%was achieved after 20,000 cycles.This work provides an ANN assisted strategy for the synthesis of HOMC,highlighting its potential to valorize biomass and agricultural waste in sustainable energy storag solutions.
基金support from the National Natural Science Foundation of China(Grant Nos.52192622 and 52304003)the National Key Research and Development Program of China(Grant No.2023YFF0614102).
文摘Thermal damage mechanisms are crucial in reservoir stimulation for enhanced geothermal system(EGS).This study investigates the thermal damage mechanisms in granite samples from the Gonghe Basin,Qinghai,China.The granite samples were heated to 400℃ and then cooled in air,water,or liquid nitrogen.The physical and mechanical properties of the thermally treated granite were evaluated,andmicrostructural changes were analyzed using a scanning electron microscope(SEM)and computed tomography(CT).The results indicate that cooling with water and liquid nitrogen significantly enhancespermeability and brittleness while reducing P-wave velocity,strength,and Young's modulus.Specifically,liquid nitrogen cooling increased granite permeability by a factor of 5.24 compared to the untreatedsamples,while reducing compressive strength by 13.6%.After thermal treatment,the failure mode of thegranite shifted from axial splitting to a combination of shear and tension.Microstructural analysisrevealed that liquid nitrogen-cooled samples exhibited greater fracture complexity than those cooledwith water or air.Additionally,acoustic emission(AE)monitoring during damage evolution showed thatliquid nitrogen cooling led to higher cumulative AE energy and a lower maximum AE energy rate,withnumerous AE signals detected during both stable and unstable crack growth.The results suggest thatliquid nitrogen induces a stronger thermal shock,leading to more significant thermal damage andpromoting the development of a complex fracture network during EGS reservoir stimulation.This enhancesboth the heat exchange area and the permeability of the deep hot dry rock(HDR)in EGS reservoirs.The insights from this study contribute to a deeper understanding of thermal damagecharacteristics induced by different cooling media and provide valuable guidance for optimizing deepgeothermal energy extraction.
基金supported by the National Natural Science Foundation of China(32370386,32070372,and 32200295)Science Foundation for Distinguished Young Scholars of Shaanxi Province(2023-JC-JQ-22)+4 种基金Basic Research Project of Shaanxi Academy of Fundamental Science(22JHZ005)Shaanxi Key Research and Development Program(2024NC-YBXM-064)Science and Technology Program of Shaanxi Academy of Science(2023K-49,2023K-26,and 2019K-06)Shaanxi Forestry Science and Technology Innovation Key Project(SXLK2023-02-20)Qinling Hundred Talents Project of Shaanxi Academy of Science(Y23Z619F17).
文摘Intraspecific genetic variance and gene flow can support the adaptive evolution of species challenged by climate shifts or novel environmental conditions.Less well understood is how genome organization and gene flow interact in closely related species during evolutionary divergence and differentiation.Here we conducted genomic footprint analyses to determine how three species of Pterocarya(P.stenoptera,P.hupehensis,and P.macroptera),which are sympatric but occupy different elevational niches,adapted to the heterogeneous environment of the Qinling-Daba Mountains,China.We identified candidate genes for environmental adaptation(i.e.,PIEZO1,WRKY39,VDAC3,CBL1,and RAF),and also identified regions of gene introgression between P.hupehensis and P.macroptera that show lower genetic load and higher genetic diversity than the rest of their genomes.The same introgressed regions are notably situated in areas of minimal genetic divergence yet they are characterized by elevated recombination rates.We also identified candidate genes within these introgressed regions related to environmental adaptation(TPLC2,CYCH;1,LUH,bHLH112,GLX1,TLP-3,and ABC1).Our findings have thus clarified the important role of gene flow in ecological adaptation and revealed genomic signatures of past introgression.Together,these findings provide a stronger theoretical basis for understanding the ecological adaptation and conservation of Quaternary relict woody plants in East Asia.
基金supported by National Natural Science Foundation of China(No.22278352)National Key Research and Development Program of China(No.2021YFC3001100)+3 种基金Longyan City Science and Technology Plan Project(No.2020LYF17043)Longyan City Science and Technology Plan Project(No.2020LYF17042)ARC Discovery Project(No.DP200101238)and NHMRC Investigator Grant(No.APP2008698)supported by the Harvard Materials Research Science and Engineering Center(No.DMR2011754)。
文摘Biocompatible amphiphilic nanoparticles(NPs)with tunable particle morphology and surface property are important for their applications as functional materials.However,previously developed methods to prepare amphiphilic NPs generally involve several steps,especially an additional step for surface modification,greatly hindering their largescale production and widespread applications.Here,a versatile one-step strategy is developed to prepare biocompatible amphiphilic dimer NPs with tunable particle morphology and surface property.The amphiphilic dimer NPs,which consist of a hydrophobic shellac bulb and a hydrophilic poly(lactic acid)(PLA)bulb with PLA-poly(ethylene glycol)(PEG)on the bulb surface,are prepared in a single step by controlled co-precipitation and self-assembly.Amphiphilic PLA-PEG/shellac dimer NPs demonstrate excellent tunability in particle morphology,thus showing good performances in controlling the interfacial curvature and emulsion type.In addition,temperatureresponsive PLA-poly(N-isopropyl acrylamide)(PNIPAM)/shellac dimer NPs are prepared following the same method and emulsions stabilized by them show temperature-triggered response.The applications of PLA-PEG-folic acid(FA)/shellac dimer NPs for drug delivery have also been demonstrated,which show a very good performance.The strategy of preparing the dimer NPs is green,scalable,facile and versatile,which provides a good platform for the design of dimer NPs with tunable particle morphology and surface property for diverse applications.
基金supported by the National Key Research and Development Program of China(Grant Nos.2023YFF0614102 and 2023YFE0110900)the National Natural Science Foundation of China(Grant Nos.52374004,52204005,and 52304003)the Natural Science Foundation of Sichuan Province(Grant Nos.2024NSFSC0961 and 2023NSFSC0940).
文摘China's shale oil and gas resources are widely distributed in shale-sandstone interbedded reservoirs,whose complex lithology and strong heterogeneity pose significant challenges to hydraulic fracturing design.To address issues such as the difficulty in controlling fracture height and the challenge of forming an effective fracture network,this study utilizes synthetic rock samples that can represent the characteristics of interbedded reservoirs and investigates the initiation and propagation of hydraulic fractures under different viscosity,injection rate,and construction scheme.By combining real-time monitoring of injection pressure with acoustic emission,the temporal and spatial evolution characteristics of hydraulic fractures as well as the mechanisms of their vertical and horizontal extension are revealed.The results indicate that a higher fracturing fluid viscosity is essential for ensuring the vertical cross-layer propagation of hydraulic fractures,while a lower fluid viscosity facilitates the activation of weak interlayer surfaces,promoting sufficient horizontal propagation along these planes and forming branched fractures.Although a higher injection rate enhances the vertical cross-layer propagation of hydraulic fractures,it also causes greater diversion of the main fracture plane,resulting in simpler fracture morphology and limiting the stimulation effect.Additionally,an alternating injection of high and low viscosity fracturing fluids allows hydraulic fractures to both break through weak interlayer surfaces and achieve uniform horizontal propagation,resulting in a more complex fracture morphology.The findings are expected to provide a scientific basis and practical guidance for optimizing hydraulic fracturing designs in interbedded reservoir conditions.
