Second-order Born calculations are performed to investigate the triple differential cross sections of coplanar asymmetric laser-assisted （e, 2e） collisions for hydrogen and helium targets. The incident electron is c...Second-order Born calculations are performed to investigate the triple differential cross sections of coplanar asymmetric laser-assisted （e, 2e） collisions for hydrogen and helium targets. The incident electron is considered to be dressed by the laser field in a nonperturbative manner by choosing the Volkov solutions in both the initial and final channels. Detailed calculations of the scattering amplitudes are performed using the Sturmian basis expansion. The state of the ejected electron is described by a Coulomb-Volkov wave function. Two geometries are investigated in which the laser polarization vector is either parallel to the incident momentum of the projectile or parallel to the momentum transfer. Our numerical results show that, in the low energy range, these two laser polarization orientations give the same shape and the same order of magnitude of laser-assisted ionization cross sections of helium and hydrogen targets.展开更多
Geochemical reactions play a vital role in determining the efficiency of carbon capture,utilization,and storage combined with enhanced oil recovery(CCUS-EOR),particularly through their influence on reservoir propertie...Geochemical reactions play a vital role in determining the efficiency of carbon capture,utilization,and storage combined with enhanced oil recovery(CCUS-EOR),particularly through their influence on reservoir properties.To deepen the understanding of these mechanisms,this review investigates the interactions among injected CO_(2),formation fluids,and rock minerals and evaluates their implications for CCUS-EOR performance.The main results are summarized as follows.First,temperature,pressure,pH,and fluid composition are identified as key factors influencing mineral dissolution and precipitation,which in turn affect porosity,permeability,and CO_(2) storage.Second,carbonate minerals,such as calcite and dolomite,show high reactivity under lower temperature conditions,enhancing dissolution and permeability,while silicate minerals,including illite,kaolinite,quartz,and K-feldspar,are comparatively inert.Third,the formation of carbonic acid during CO_(2) injection promotes dissolution,whereas secondary precipitation,especially of clay minerals,can reduce pore connectivity and limit flow paths.Fourth,mineral transformation and salt precipitation can further modify reservoir characteristics,influencing both oil recovery and long-term CO_(2) trapping.Fifth,advanced experimental tools,such as Computed Tomography(CT)and Nuclear Magnetic Resonance(NMR)imaging,combined with geochemical modeling and reservoir simulation,are essential to predict petrophysical changes across scales.This review provides a theoretical foundation for integrating geochemical processes into CCUS-EOR design,offering technical support for field application and guiding sustainable CO_(2) management in oil reservoirs.展开更多
Asymmetric single-atom catalysts(ASACs)have attracted much attention owing to their excellent catalytic properties.However,the relationship between asymmetric coordination and the spin states of metal sites remains un...Asymmetric single-atom catalysts(ASACs)have attracted much attention owing to their excellent catalytic properties.However,the relationship between asymmetric coordination and the spin states of metal sites remains unclear.Additionally,the modulation of reactive oxygen species in Fenton-like reactions remains challenging.Herein,a novel strategy is reported for the rational design of highly loaded Co ASACs(CoN_(1)C_(2)/C_(2)N)immobilized on three-dimensional flower-like C_(2)N using an in situ-generated carbon defect method.In particular,the asymmetrically tricoordinated CoN_(1)C_(2)/C_(2)N exhibited excellent catalytic activity for sulfachloropyridazine degradation,with a turnover frequency of 36.8 min^(–1).Experimental results and theoretical calculations revealed that the electron spin state of the Co-active sites was transferred from the low-spin configuration(t_(2g)^(6)e_(g)^(1))to the high-spin configuration(t_(2g)^(5)e_(g)^(2))owing to asymmetric coordination.The high-spin Co 3d orbital in CoN_(1)C_(2)/C_(2)N possessed more unpaired electrons and therefore,had a strong ability to gain electrons from the O 2p orbitals of HSO_(5)^(–),boosting d-p orbital hybridization.More importantly,the spin-electron filling in theσ^(*)orbital of high-spin Co 3d−O 2p accelerated the desorption of^(*)SO_(5)•^(−),which acted as a rate-limiting step in the reaction,thus facilitating more^(1)O_(2)generation.This study provides an innovative synthetic route for practical ASACs and clarifies the critical relationship between structure and spin state,paving the way for advancements in environmental remediation and energy conversion applications.展开更多
Three-dimensional(3D)covalent organic frameworks(COFs)have attracted extensive attention as photocatalysts for CO_(2)reduction reactions.Introducing metal atoms is essential for enhancing activity,but previous metal s...Three-dimensional(3D)covalent organic frameworks(COFs)have attracted extensive attention as photocatalysts for CO_(2)reduction reactions.Introducing metal atoms is essential for enhancing activity,but previous metal sites in 3D COFs predominantly exhibit symmetrical coordination,making them unsuitable for CO_(2)activation.Here,we design a 3D COF with 2,2'-pyridine linked around tetra-(4-anilyl)methane(TCM-Bpy-COF),where Co^(2+)is asymmetrically coordinated by bipyridine and acetates(TCMBpy-COF-CoAc).The TCM-Bpy-COF-CoAc exhibits outstanding photocatalytic CO_(2)reduction performance under weak visible light,achieving a CO evolution rate of 26,650μmol g^(-1)h^(-1)under 5 W of lightemitting-diode(LED)lamp and high apparent quantum efficiency.The performance far exceeds that of symmetrically coordinated bipyridine-Co-bipyridine TCM-Bpy-COF and surpasses most reported COF-based photocatalysts.In-situ spectral characterizations and theoretical calculations show that asymmetric N,O-coordination around the Co^(2+)center polarizes electron density and lowers reaction energy barriers of^(*)COOH intermediates,enhancing the conversion of CO_(2)to CO.This work inspires the design of 3D COF-based photocatalysts with highly catalytic efficiency.展开更多
文摘Second-order Born calculations are performed to investigate the triple differential cross sections of coplanar asymmetric laser-assisted （e, 2e） collisions for hydrogen and helium targets. The incident electron is considered to be dressed by the laser field in a nonperturbative manner by choosing the Volkov solutions in both the initial and final channels. Detailed calculations of the scattering amplitudes are performed using the Sturmian basis expansion. The state of the ejected electron is described by a Coulomb-Volkov wave function. Two geometries are investigated in which the laser polarization vector is either parallel to the incident momentum of the projectile or parallel to the momentum transfer. Our numerical results show that, in the low energy range, these two laser polarization orientations give the same shape and the same order of magnitude of laser-assisted ionization cross sections of helium and hydrogen targets.
基金support from the National Natural Science Foundation of China(No.52304048)supported by the Sichuan Science and Technology Program(No.2025ZNSFSC1355)the Open Fund(No.PLN202428)of the State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation at Southwest Petroleum University.
文摘Geochemical reactions play a vital role in determining the efficiency of carbon capture,utilization,and storage combined with enhanced oil recovery(CCUS-EOR),particularly through their influence on reservoir properties.To deepen the understanding of these mechanisms,this review investigates the interactions among injected CO_(2),formation fluids,and rock minerals and evaluates their implications for CCUS-EOR performance.The main results are summarized as follows.First,temperature,pressure,pH,and fluid composition are identified as key factors influencing mineral dissolution and precipitation,which in turn affect porosity,permeability,and CO_(2) storage.Second,carbonate minerals,such as calcite and dolomite,show high reactivity under lower temperature conditions,enhancing dissolution and permeability,while silicate minerals,including illite,kaolinite,quartz,and K-feldspar,are comparatively inert.Third,the formation of carbonic acid during CO_(2) injection promotes dissolution,whereas secondary precipitation,especially of clay minerals,can reduce pore connectivity and limit flow paths.Fourth,mineral transformation and salt precipitation can further modify reservoir characteristics,influencing both oil recovery and long-term CO_(2) trapping.Fifth,advanced experimental tools,such as Computed Tomography(CT)and Nuclear Magnetic Resonance(NMR)imaging,combined with geochemical modeling and reservoir simulation,are essential to predict petrophysical changes across scales.This review provides a theoretical foundation for integrating geochemical processes into CCUS-EOR design,offering technical support for field application and guiding sustainable CO_(2) management in oil reservoirs.
文摘Asymmetric single-atom catalysts(ASACs)have attracted much attention owing to their excellent catalytic properties.However,the relationship between asymmetric coordination and the spin states of metal sites remains unclear.Additionally,the modulation of reactive oxygen species in Fenton-like reactions remains challenging.Herein,a novel strategy is reported for the rational design of highly loaded Co ASACs(CoN_(1)C_(2)/C_(2)N)immobilized on three-dimensional flower-like C_(2)N using an in situ-generated carbon defect method.In particular,the asymmetrically tricoordinated CoN_(1)C_(2)/C_(2)N exhibited excellent catalytic activity for sulfachloropyridazine degradation,with a turnover frequency of 36.8 min^(–1).Experimental results and theoretical calculations revealed that the electron spin state of the Co-active sites was transferred from the low-spin configuration(t_(2g)^(6)e_(g)^(1))to the high-spin configuration(t_(2g)^(5)e_(g)^(2))owing to asymmetric coordination.The high-spin Co 3d orbital in CoN_(1)C_(2)/C_(2)N possessed more unpaired electrons and therefore,had a strong ability to gain electrons from the O 2p orbitals of HSO_(5)^(–),boosting d-p orbital hybridization.More importantly,the spin-electron filling in theσ^(*)orbital of high-spin Co 3d−O 2p accelerated the desorption of^(*)SO_(5)•^(−),which acted as a rate-limiting step in the reaction,thus facilitating more^(1)O_(2)generation.This study provides an innovative synthetic route for practical ASACs and clarifies the critical relationship between structure and spin state,paving the way for advancements in environmental remediation and energy conversion applications.
基金financial support from the National Natural Science Foundation of China(No.22072183)the Natural Science Foundation of Hunan Province,China(No.2022JJ30690)supported in part by the High Performance Computing Center of Central South University。
文摘Three-dimensional(3D)covalent organic frameworks(COFs)have attracted extensive attention as photocatalysts for CO_(2)reduction reactions.Introducing metal atoms is essential for enhancing activity,but previous metal sites in 3D COFs predominantly exhibit symmetrical coordination,making them unsuitable for CO_(2)activation.Here,we design a 3D COF with 2,2'-pyridine linked around tetra-(4-anilyl)methane(TCM-Bpy-COF),where Co^(2+)is asymmetrically coordinated by bipyridine and acetates(TCMBpy-COF-CoAc).The TCM-Bpy-COF-CoAc exhibits outstanding photocatalytic CO_(2)reduction performance under weak visible light,achieving a CO evolution rate of 26,650μmol g^(-1)h^(-1)under 5 W of lightemitting-diode(LED)lamp and high apparent quantum efficiency.The performance far exceeds that of symmetrically coordinated bipyridine-Co-bipyridine TCM-Bpy-COF and surpasses most reported COF-based photocatalysts.In-situ spectral characterizations and theoretical calculations show that asymmetric N,O-coordination around the Co^(2+)center polarizes electron density and lowers reaction energy barriers of^(*)COOH intermediates,enhancing the conversion of CO_(2)to CO.This work inspires the design of 3D COF-based photocatalysts with highly catalytic efficiency.
