The Si3N4-bonded silicon carbide(SiC)bricks in the sloped zone of dry quenching coke ovens support the weight of upper refractory materials and equipment.These bricks endure frequent temperature fluctuations and...The Si3N4-bonded silicon carbide(SiC)bricks in the sloped zone of dry quenching coke ovens support the weight of upper refractory materials and equipment.These bricks endure frequent temperature fluctuations and intense abrasion from coke dust,demanding extremely high performance.After three years of service,an analysis of the Si3N4-bonded SiC bricks revealed that oxidation,which reduces thermal shock resistance,is the primary cause of degradation.In the unused Si3N4-bonded SiC bricks,short columnar β-Si3N4 forms an interwoven network around SiC particles and contains a small amount of plate-like Si2N2O.Under the complex N2(84.42 vol.%)-CO2(10.44 vol.%)-CO(4.43 vol.%)-H2(0.56 vol.%)-O2(0.15 vol.%)atmosphere in the dry quenching coke oven,O2(0.15 vol.%)exhibits a stronger oxidizing effect than CO2(10.44 vol.%)and CO(4.43 vol.%),making it the primary oxidizing agent.The short columnarβ-Si3N4 is more susceptible to oxidation than the particulate SiC.Based on thermodynamic and kinetic analyses,the chemical stability of the phases in Si3N4-bonded SiC bricks ranks from strongest to weakest as follows:Si2N2O,SiC,Si3N4.Future development of Si2N2O-bonded SiC bricks could improve the longevity of refractory materials in the sloped zone of dry quenching coke ovens.展开更多
To explain the influence mechanism of MgO on the consolidation and reduction characteristics of roasted iron pellets,the properties and structure of pellets were investigated from multi-dimensions.It indicated that th...To explain the influence mechanism of MgO on the consolidation and reduction characteristics of roasted iron pellets,the properties and structure of pellets were investigated from multi-dimensions.It indicated that the MgO addition decreased the reduction swelling index(RSI)and reduction degree of pellets in both CO and H2atmospheres.During the stepwise reduction process of Fe2O3→Fe3O4→FeO,the reduction behaviour of pellets in CO and H2was similar,while the reduction rate of pellets in H2atmosphere was almost twice as high as that in CO atmosphere.During the stepwise reduction process of FeO→Fe,the RSI of pellets showed a logarithmic increase in CO atmosphere and a linear decrease in H2atmosphere.As investigated by first-principles calculations,C and Fe mainly formed chemical bonds,and the CO reduction process released energy,promoting the formation of iron whiskers.However,H and Fe produced weak physical adsorption,and the H2reduction process was endothermic,inhibiting the generation of iron whiskers.With Mg2+doping in FexO,the nucleation region of iron whiskers expanded in CO reduction process,and the morphology of iron whiskers transformed from“slender”to“stocky,”reducing RSI of the pellets.展开更多
This study develops a two-dimensional fluid model for atmospheric pressure non-equilibrium CO2-H2O plasma needle-plate configuration,incorporating a comprehensive set of plasma chemical reactions and photoioniza...This study develops a two-dimensional fluid model for atmospheric pressure non-equilibrium CO2-H2O plasma needle-plate configuration,incorporating a comprehensive set of plasma chemical reactions and photoionization effects.It focuses on investigating the influence of the CO2/H2O concentration ratio and quenching pressure on plasma streamer initiation and propagation dynamics.Numerical simulations show that increasing initial water vapor content significantly reduces electron energy and density,causing the discharge channel to contract when the reduced electric field is below 200 Td,due to strong dissociative adsorption reactions between electrons and water molecules.At higher reduced electric fields(above 200 Td),variations in water vapor content have minimal impact on primary electron transport parameters,likely because dissociative and ionizing collisions between electrons and CO2/H2O molecules become dominant.Increasing the quenching pressure enhances photoionization,but plasma discharge remains primarily sustained by direct electron-impact ionization.Low initial water vapor content and elevated quenching pressure both accelerate streamer propagation,with the concentration ratio exerting a more significant effect.Finally,the primary reaction pathways for key products(CO,OH,and electrons)are analyzed.These findings contribute to a better understanding of how the reactant concentration ratio and quenching pressure regulate the discharge reaction mechanism in atmospheric pressure non-equilibrium CO2-H2O plasma.展开更多
为探究稻茬小麦深施肥“一基一追”机艺融合技术的增产增效减排机制,2021—2024年在长江下游南通稻茬麦区开展大田试验。试验采用缓释掺混肥料(SRF,N∶P2O5∶K2O=26∶12∶12)和普通尿素(U,46%N),结合自主研发的2BFGK-12(6)260...为探究稻茬小麦深施肥“一基一追”机艺融合技术的增产增效减排机制,2021—2024年在长江下游南通稻茬麦区开展大田试验。试验采用缓释掺混肥料(SRF,N∶P2O5∶K2O=26∶12∶12)和普通尿素(U,46%N),结合自主研发的2BFGK-12(6)260全秸秆茬地洁区旋耕智能施肥播种机和3ZF-4(200)中耕追肥机,设置7种施肥模式(30 cm+15 cm宽窄行种植):以尿素4次分施(N 240 kg hm-2,基肥∶分蘖肥∶拔节肥∶孕穗肥=5∶1∶2∶2,窄行基施,追肥全田撒施)为对照(CK);减氮15%(N 204 kg hm-2)条件下设置6种处理:M1(100%SRF窄行基施);M2(60%SRF窄行基施+40%U拔节期窄行撒施);M3(60%SRF窄行基施+40%U返青期宽行条施);M4(60%SRF窄行基施+40%SRF返青期窄行撒施);M5(60%SRF窄行基施+40%SRF返青期宽行条施);M4+5(60%SRF窄行基施+20%SRF返青期宽行条施+20%SRF返青期窄行撒施)。研究比较不同施肥模式对小麦产量效益、根系形态生理、氮素利用效率及N2O排放的影响。结果表明,与CK相比,M2~M5处理提高了小麦产量(4.0%~19.0%)和经济效益(13.7%~35.7%),其中M4和M5处理表现最优,分别增产14.1%和19.0%,经济效益提升34.5%和35.7%。这些处理明显改善了根系特性(根干重密度增加9.7%~111.8%,根系活力和氧化力分别提高6.8%~52.0%和4.2%~44.2%),降低N2O累积排放量22.6%~34.5%,提高0~20 cm土层硝态氮含量11.2%~40.0%。在氮素利用方面,M2~M5处理均提高了籽粒氮素积累量、花后氮素积累量及其对籽粒氮素的贡献率,氮肥利用效率指标(包括偏生产力、农学效率和表观利用率)分别显著提升了22.4%~40.0%、29.7%~74.3%和9.41~18.77个百分点。值得注意的是,M4和M5处理表现出最优的综合效益:N2O累积排放量降幅最大(分别达27.0%和34.5%),氮肥表观利用率2季均维持在43.0%以上(均值分别为43.5%和46.8%),同时在生育后期保持较高的根系活性和耕层无机氮含量。相比之下,M1处理虽然实现了最大的N2O减排效果(降幅35.9%),但导致减产10.4%和经济效益下降10.8%,且氮肥利用效率呈现不稳定的年际变化特征。而优化处理M4+5进一步改善了根系形态生理特性,并提高氮肥表观利用率和籽粒氮素积累量。综上,减氮15%条件下(N 204 kg hm-2),缓混肥2次施用处理(M4和M5)能实现产量、经济效益、氮肥利用效率和N2O减排的协同提高,并以追肥深施处理(M5)效应更强。本研究为稻茬小麦缓释肥减氮优化高效应用提供重要理论依据。展开更多
Photo-assisted Mg/seawater batteries(PAMSBs)are attractive power source for marine equipment due to the advan tage of simultaneous generation of electricity an d hydrogen from seawater.Nonetheless,the serious photocor...Photo-assisted Mg/seawater batteries(PAMSBs)are attractive power source for marine equipment due to the advan tage of simultaneous generation of electricity an d hydrogen from seawater.Nonetheless,the serious photocorrosion of photocathodes results in dissatisfactory battery performan ce,which substantially hinder their practical applications.Herein,we design a CuO/Cu2O heterostructure as the photocathode of PAMSBs via a facile in-situ electrochemical strategy,successfully enhance the photo-stability of bare Cu2O.During half-cell photoelectrochemical water splitting,the newly-developed CuO/Cu2O photocathode reveals a photo-current density about 2.2 mA cm-2at 0 V(vs.RHE)and enables nearly 100% retention of the initial photocurrent density after 2h long-term operation,more than 10 times stable than the bare Cu2O photocathode.A PAMSB with a CuO/Cu2O photocathode achieves a maximum power density up to 22.67 mW cm-2and a hydrogen yield rate up to 1.18 mL cm-2min-1,much higher than those obtained with a bare Cu2O photocathode.This study offers a simple and convenient electrochemical strategy for in-situ fabrication of CuO/Cu2O heterojunction photocathodes,and also demonstrate the feasibility of PAMSBs as a power source and a hydrogen generator,which lays foundation for its future marine application.展开更多
基金support from the National Natural Science Foundation of China(52172023 and 52302027).
摘要The Si3N4-bonded silicon carbide(SiC)bricks in the sloped zone of dry quenching coke ovens support the weight of upper refractory materials and equipment.These bricks endure frequent temperature fluctuations and intense abrasion from coke dust,demanding extremely high performance.After three years of service,an analysis of the Si3N4-bonded SiC bricks revealed that oxidation,which reduces thermal shock resistance,is the primary cause of degradation.In the unused Si3N4-bonded SiC bricks,short columnar β-Si3N4 forms an interwoven network around SiC particles and contains a small amount of plate-like Si2N2O.Under the complex N2(84.42 vol.%)-CO2(10.44 vol.%)-CO(4.43 vol.%)-H2(0.56 vol.%)-O2(0.15 vol.%)atmosphere in the dry quenching coke oven,O2(0.15 vol.%)exhibits a stronger oxidizing effect than CO2(10.44 vol.%)and CO(4.43 vol.%),making it the primary oxidizing agent.The short columnarβ-Si3N4 is more susceptible to oxidation than the particulate SiC.Based on thermodynamic and kinetic analyses,the chemical stability of the phases in Si3N4-bonded SiC bricks ranks from strongest to weakest as follows:Si2N2O,SiC,Si3N4.Future development of Si2N2O-bonded SiC bricks could improve the longevity of refractory materials in the sloped zone of dry quenching coke ovens.
基金support from the National Natural Science Foundation of China(52174290).
摘要To explain the influence mechanism of MgO on the consolidation and reduction characteristics of roasted iron pellets,the properties and structure of pellets were investigated from multi-dimensions.It indicated that the MgO addition decreased the reduction swelling index(RSI)and reduction degree of pellets in both CO and H2atmospheres.During the stepwise reduction process of Fe2O3→Fe3O4→FeO,the reduction behaviour of pellets in CO and H2was similar,while the reduction rate of pellets in H2atmosphere was almost twice as high as that in CO atmosphere.During the stepwise reduction process of FeO→Fe,the RSI of pellets showed a logarithmic increase in CO atmosphere and a linear decrease in H2atmosphere.As investigated by first-principles calculations,C and Fe mainly formed chemical bonds,and the CO reduction process released energy,promoting the formation of iron whiskers.However,H and Fe produced weak physical adsorption,and the H2reduction process was endothermic,inhibiting the generation of iron whiskers.With Mg2+doping in FexO,the nucleation region of iron whiskers expanded in CO reduction process,and the morphology of iron whiskers transformed from“slender”to“stocky,”reducing RSI of the pellets.
基金supported by the financial support provided by the National Natural Science Foundation of China(Grant Nos.12475261,12065019,and 12405296)the Qing Lan Project of Jiangsu Province,and the Yancheng Basic Research Fund Project of China(Grant No.YCBK2024003).
摘要This study develops a two-dimensional fluid model for atmospheric pressure non-equilibrium CO2-H2O plasma needle-plate configuration,incorporating a comprehensive set of plasma chemical reactions and photoionization effects.It focuses on investigating the influence of the CO2/H2O concentration ratio and quenching pressure on plasma streamer initiation and propagation dynamics.Numerical simulations show that increasing initial water vapor content significantly reduces electron energy and density,causing the discharge channel to contract when the reduced electric field is below 200 Td,due to strong dissociative adsorption reactions between electrons and water molecules.At higher reduced electric fields(above 200 Td),variations in water vapor content have minimal impact on primary electron transport parameters,likely because dissociative and ionizing collisions between electrons and CO2/H2O molecules become dominant.Increasing the quenching pressure enhances photoionization,but plasma discharge remains primarily sustained by direct electron-impact ionization.Low initial water vapor content and elevated quenching pressure both accelerate streamer propagation,with the concentration ratio exerting a more significant effect.Finally,the primary reaction pathways for key products(CO,OH,and electrons)are analyzed.These findings contribute to a better understanding of how the reactant concentration ratio and quenching pressure regulate the discharge reaction mechanism in atmospheric pressure non-equilibrium CO2-H2O plasma.
摘要为探究稻茬小麦深施肥“一基一追”机艺融合技术的增产增效减排机制,2021—2024年在长江下游南通稻茬麦区开展大田试验。试验采用缓释掺混肥料(SRF,N∶P2O5∶K2O=26∶12∶12)和普通尿素(U,46%N),结合自主研发的2BFGK-12(6)260全秸秆茬地洁区旋耕智能施肥播种机和3ZF-4(200)中耕追肥机,设置7种施肥模式(30 cm+15 cm宽窄行种植):以尿素4次分施(N 240 kg hm-2,基肥∶分蘖肥∶拔节肥∶孕穗肥=5∶1∶2∶2,窄行基施,追肥全田撒施)为对照(CK);减氮15%(N 204 kg hm-2)条件下设置6种处理:M1(100%SRF窄行基施);M2(60%SRF窄行基施+40%U拔节期窄行撒施);M3(60%SRF窄行基施+40%U返青期宽行条施);M4(60%SRF窄行基施+40%SRF返青期窄行撒施);M5(60%SRF窄行基施+40%SRF返青期宽行条施);M4+5(60%SRF窄行基施+20%SRF返青期宽行条施+20%SRF返青期窄行撒施)。研究比较不同施肥模式对小麦产量效益、根系形态生理、氮素利用效率及N2O排放的影响。结果表明,与CK相比,M2~M5处理提高了小麦产量(4.0%~19.0%)和经济效益(13.7%~35.7%),其中M4和M5处理表现最优,分别增产14.1%和19.0%,经济效益提升34.5%和35.7%。这些处理明显改善了根系特性(根干重密度增加9.7%~111.8%,根系活力和氧化力分别提高6.8%~52.0%和4.2%~44.2%),降低N2O累积排放量22.6%~34.5%,提高0~20 cm土层硝态氮含量11.2%~40.0%。在氮素利用方面,M2~M5处理均提高了籽粒氮素积累量、花后氮素积累量及其对籽粒氮素的贡献率,氮肥利用效率指标(包括偏生产力、农学效率和表观利用率)分别显著提升了22.4%~40.0%、29.7%~74.3%和9.41~18.77个百分点。值得注意的是,M4和M5处理表现出最优的综合效益:N2O累积排放量降幅最大(分别达27.0%和34.5%),氮肥表观利用率2季均维持在43.0%以上(均值分别为43.5%和46.8%),同时在生育后期保持较高的根系活性和耕层无机氮含量。相比之下,M1处理虽然实现了最大的N2O减排效果(降幅35.9%),但导致减产10.4%和经济效益下降10.8%,且氮肥利用效率呈现不稳定的年际变化特征。而优化处理M4+5进一步改善了根系形态生理特性,并提高氮肥表观利用率和籽粒氮素积累量。综上,减氮15%条件下(N 204 kg hm-2),缓混肥2次施用处理(M4和M5)能实现产量、经济效益、氮肥利用效率和N2O减排的协同提高,并以追肥深施处理(M5)效应更强。本研究为稻茬小麦缓释肥减氮优化高效应用提供重要理论依据。
基金financially supported by National Natural Science Foundation of China(Nos.22179067 and 22279069)Major Fundamental Research Program of Natural Science Foundation of Shandong Province(No.ZR2022ZD10)。
摘要Photo-assisted Mg/seawater batteries(PAMSBs)are attractive power source for marine equipment due to the advan tage of simultaneous generation of electricity an d hydrogen from seawater.Nonetheless,the serious photocorrosion of photocathodes results in dissatisfactory battery performan ce,which substantially hinder their practical applications.Herein,we design a CuO/Cu2O heterostructure as the photocathode of PAMSBs via a facile in-situ electrochemical strategy,successfully enhance the photo-stability of bare Cu2O.During half-cell photoelectrochemical water splitting,the newly-developed CuO/Cu2O photocathode reveals a photo-current density about 2.2 mA cm-2at 0 V(vs.RHE)and enables nearly 100% retention of the initial photocurrent density after 2h long-term operation,more than 10 times stable than the bare Cu2O photocathode.A PAMSB with a CuO/Cu2O photocathode achieves a maximum power density up to 22.67 mW cm-2and a hydrogen yield rate up to 1.18 mL cm-2min-1,much higher than those obtained with a bare Cu2O photocathode.This study offers a simple and convenient electrochemical strategy for in-situ fabrication of CuO/Cu2O heterojunction photocathodes,and also demonstrate the feasibility of PAMSBs as a power source and a hydrogen generator,which lays foundation for its future marine application.