Tunable magnetic phase transition in two-dimensional materials is a fascinating subject of research.We perform first-principle calculations based on density functional theory to clarify the magnetic property of CrSeTe...Tunable magnetic phase transition in two-dimensional materials is a fascinating subject of research.We perform first-principle calculations based on density functional theory to clarify the magnetic property of CrSeTe monolayer modulated by the biaxial compressive strain.Based on the stable structure confirmed by the phonon calculation,CrSeTe is determined to be a ferromagnetic metal that undergoes a phase transition from a ferromagnetic state to an antiferromagnetic state with nearly 2.75%compressive strain.We identify the stress-magnetism behavior originating from the changes in interactions between the nearest-neighboring Cr atoms(J_(1)) and the next-nearest-neighboring Cr atoms(J_(2)).Through Monte Carlo simulation,we find that the Curie temperature of the CrSeTe monolayer is 160 K.The CrSeTe monolayer could be an intriguing platform for the two-dimensional systems and potential spintronic material.展开更多
Due to the limited hydration capacity,solidification/stabilization(S/S)with waste concrete powder(WCP)has a low strength.Carbonation can reduce carbon dioxide(CO_(2))emissions and improve strength of lead-contaminated...Due to the limited hydration capacity,solidification/stabilization(S/S)with waste concrete powder(WCP)has a low strength.Carbonation can reduce carbon dioxide(CO_(2))emissions and improve strength of lead-contaminated soil,but its mechanism and environmental behaviors are unclear.In light of this,a comprehensive study was conducted on the compressive strength,lead immobilization,conductivity characteristics,and carbonation mechanism of carbonated Pb-contaminated soils stabilized with WCP compared to calcining 600℃WCP.Results indicated that with carbonation,the compressive strength of the samples was significantly improved at the early stage(1 d),resulting in increased unconfined compressive strength(UCS)by 2.5-5.2 times due to the filling of pores by calcite.It negatively affected the lead immobilization capacity of highly doped(30%)samples,while this effect reversed after 3 d of carbonating due to the reduced alkaline environment.The lead immobilization capacity decreased after 28 d of carbonating due to the cracking of samples and the influence of a lower pH on the solubility of lead-carbonated hydroxide((PbCO_(3))_(2)Pb(OH)_(2)).The water evaporation(saturation<16.8%)led to dry shrinkage cracking and decreased UCS of the samples.Based on this finding,a conductivity model was developed for carbonated and cured samples,accurately predicting changes in saturation levels(R^(2)=0.98).A relationship between conductivity and UCS or lead immobilization capacity was proposed.This research proposed an innovative method for the reduction of CO_(2)emission as well as laid down a theoretical basis for the recovery of WCP and lead-contaminated soils through carbonation.展开更多
基金the National Natural Science Foundation of China(Grant Nos.61874060,U1932159,and 61911530220)the Natural Science Foundation of Jiangsu Province(Grant No.BK20181388)+3 种基金the Natural Science Research of Jiangsu Higher Education Institutions of China(Grant No.21KJD140005)the Foundation of Nanjing University of Posts and Telecommunications(NUPT)‘1311 Talent Program’supported by the Natural Science Foundation of Jiangsu Province(Grant No.20KJB430010)NUPTSF(Grant No.NY219164)。
文摘Tunable magnetic phase transition in two-dimensional materials is a fascinating subject of research.We perform first-principle calculations based on density functional theory to clarify the magnetic property of CrSeTe monolayer modulated by the biaxial compressive strain.Based on the stable structure confirmed by the phonon calculation,CrSeTe is determined to be a ferromagnetic metal that undergoes a phase transition from a ferromagnetic state to an antiferromagnetic state with nearly 2.75%compressive strain.We identify the stress-magnetism behavior originating from the changes in interactions between the nearest-neighboring Cr atoms(J_(1)) and the next-nearest-neighboring Cr atoms(J_(2)).Through Monte Carlo simulation,we find that the Curie temperature of the CrSeTe monolayer is 160 K.The CrSeTe monolayer could be an intriguing platform for the two-dimensional systems and potential spintronic material.
基金supported by the National Natural Science Foundation of China(62090035,U19A2090,61905071)the Key Program of the Hunan Provincial Science and Technology Department(2019XK2001,2020XK2001)+2 种基金the International Science and Technology Innovation Cooperation Base of Hunan Province(2018WK4004)the China Postdoctoral Science Foundation(2022TQ0100)the National Key Research and 288 Development Program of China(2022YFB3604701).
基金the National Natural Science Foundation of China(Grant Nos.42177163 and 42071080)the China Postdoctoral Science Foundation(Grant No.2022M723347).
文摘Due to the limited hydration capacity,solidification/stabilization(S/S)with waste concrete powder(WCP)has a low strength.Carbonation can reduce carbon dioxide(CO_(2))emissions and improve strength of lead-contaminated soil,but its mechanism and environmental behaviors are unclear.In light of this,a comprehensive study was conducted on the compressive strength,lead immobilization,conductivity characteristics,and carbonation mechanism of carbonated Pb-contaminated soils stabilized with WCP compared to calcining 600℃WCP.Results indicated that with carbonation,the compressive strength of the samples was significantly improved at the early stage(1 d),resulting in increased unconfined compressive strength(UCS)by 2.5-5.2 times due to the filling of pores by calcite.It negatively affected the lead immobilization capacity of highly doped(30%)samples,while this effect reversed after 3 d of carbonating due to the reduced alkaline environment.The lead immobilization capacity decreased after 28 d of carbonating due to the cracking of samples and the influence of a lower pH on the solubility of lead-carbonated hydroxide((PbCO_(3))_(2)Pb(OH)_(2)).The water evaporation(saturation<16.8%)led to dry shrinkage cracking and decreased UCS of the samples.Based on this finding,a conductivity model was developed for carbonated and cured samples,accurately predicting changes in saturation levels(R^(2)=0.98).A relationship between conductivity and UCS or lead immobilization capacity was proposed.This research proposed an innovative method for the reduction of CO_(2)emission as well as laid down a theoretical basis for the recovery of WCP and lead-contaminated soils through carbonation.
