Medium-Mn steels have attracted immense attention for automotive applications owing to their outstanding combination of high strength and superior ductility.This steel class is generally characterized by an ultrafine-...Medium-Mn steels have attracted immense attention for automotive applications owing to their outstanding combination of high strength and superior ductility.This steel class is generally characterized by an ultrafine-grained duplex microstructure consisting of ferrite and a large amount of austenite.Such a unique microstructure is processed by intercritical annealing,where austenite reversion occurs in a fine martensitic matrix.In the present study,austenite reversion in a medium-Mn alloy was simulated by the multiphase-field approach using the commercial software MICRESS®coupled with the thermodynamic database TCFE8 and the kinetic database MOBFE2.In particular,a faceted anisotropy model was incorporated to replicate the lamellar morphology of reversed austenite.The simulated microstructural morphology and phase transformation kinetics(indicated by the amount of phase)concurred well with experimental observations by scanning electron microscopy and in situ synchrotron high-energy X-ray diffraction,respectively.展开更多
We report a facile method to enhance the thermoelectric efficiency of La0.98Sr0.02CoO3-BiCuSeO by introducing BiCuSeO as a secondary phase with ultra-low thermal conductivity. Inclusion of secondary phase results in r...We report a facile method to enhance the thermoelectric efficiency of La0.98Sr0.02CoO3-BiCuSeO by introducing BiCuSeO as a secondary phase with ultra-low thermal conductivity. Inclusion of secondary phase results in reducing the total thermal conductivity by suppressing the lattice and electronic thermal conductivities and also contributes to enhancement in the Seebeck coefficient. The wide grain size distribution of Laog^Sro02CoO3-BiCuSeO composite facilitates in breaking the interlinked transport properties through increased scattering of different wavelength phonons. The combined effect of enhanced Seebeck coefficient and ultra-low thermal conductivity, results in an improved ZT value of 0.07 at 923 K. The proposed strategy can be opted for improvement in the thermoelectric efficiency of other thermoelectric materials as well.展开更多
Luminescent metal organic cages(MOCs)have attracted great interest as a unique class of sensing substrates.In this work,intrinsically fluorescent Zr-MOCs were successfully used as fluorescent probes for the sensitive ...Luminescent metal organic cages(MOCs)have attracted great interest as a unique class of sensing substrates.In this work,intrinsically fluorescent Zr-MOCs were successfully used as fluorescent probes for the sensitive and selective detection of phosphate anions in water and real samples.When the ligand and Zr ion clusters form a cage,the intrinsic fluorescence of the ligand was tuned from high to weak emission due to the ligand-to-metal charge transfer(LMCT)effect,and this weakened fluorescence can be restored by the addition of phosphate.The degree of fluorescence enhancement is positively correlated with the added phosphate concentration,and the efficacy of this strategy is demonstrated by a linear phosphate detection range of 5–500µmol/L and a detection limit of 1.06µmol/L.We discuss the interaction between phosphate and Zr in scattering spectrum and MS,respectively.In comparison to phosphate adsorption on Zr-metal organic frameworks(MOFs),where phosphate connects different numbers of cages,both blocking the LMCT effect and causing the cages to aggregate.We also found that the phosphate displaces the ligand from the cage when the phosphate concentration is further expanded,resulting in the formation of new derivatives.This derivative was shown to be useful as a Lewis acid catalyst and as a rare earth ion adsorbent.展开更多
基金The authors gratefully acknowledge the financial support of the Deutsche Forschungsgemeinschaft(DFG)within the Collaborative Research Center(SFB)761‘Steel-ab initio:Quantum mechanics guided design of new Fe-based materials’and the project BL402/49-1.H.W.Luo is thankful for the financial supports from the National Natural Science Foundation of China(Nos.51861135302 and 51831002).Dr.Bernd Böttger at ACCESS e.V.is acknowledged for the helpful discussions.The synchrotron high-energy X-ray diffraction measurements were carried out at the Powder Diffraction and Total Scattering Beamline P02.1 of PETRA III at DESY(No.I-20181007),a member of the Helmholtz Association(HGF),which is gratefully acknowledged.Dr.Martin Etter at DESY is acknowledged for his support of acquiring HEXRD data.
文摘Medium-Mn steels have attracted immense attention for automotive applications owing to their outstanding combination of high strength and superior ductility.This steel class is generally characterized by an ultrafine-grained duplex microstructure consisting of ferrite and a large amount of austenite.Such a unique microstructure is processed by intercritical annealing,where austenite reversion occurs in a fine martensitic matrix.In the present study,austenite reversion in a medium-Mn alloy was simulated by the multiphase-field approach using the commercial software MICRESS®coupled with the thermodynamic database TCFE8 and the kinetic database MOBFE2.In particular,a faceted anisotropy model was incorporated to replicate the lamellar morphology of reversed austenite.The simulated microstructural morphology and phase transformation kinetics(indicated by the amount of phase)concurred well with experimental observations by scanning electron microscopy and in situ synchrotron high-energy X-ray diffraction,respectively.
文摘We report a facile method to enhance the thermoelectric efficiency of La0.98Sr0.02CoO3-BiCuSeO by introducing BiCuSeO as a secondary phase with ultra-low thermal conductivity. Inclusion of secondary phase results in reducing the total thermal conductivity by suppressing the lattice and electronic thermal conductivities and also contributes to enhancement in the Seebeck coefficient. The wide grain size distribution of Laog^Sro02CoO3-BiCuSeO composite facilitates in breaking the interlinked transport properties through increased scattering of different wavelength phonons. The combined effect of enhanced Seebeck coefficient and ultra-low thermal conductivity, results in an improved ZT value of 0.07 at 923 K. The proposed strategy can be opted for improvement in the thermoelectric efficiency of other thermoelectric materials as well.
基金the financial support from Chengdu University of Technology (No. 10912-SJGG2021-06843)
文摘Luminescent metal organic cages(MOCs)have attracted great interest as a unique class of sensing substrates.In this work,intrinsically fluorescent Zr-MOCs were successfully used as fluorescent probes for the sensitive and selective detection of phosphate anions in water and real samples.When the ligand and Zr ion clusters form a cage,the intrinsic fluorescence of the ligand was tuned from high to weak emission due to the ligand-to-metal charge transfer(LMCT)effect,and this weakened fluorescence can be restored by the addition of phosphate.The degree of fluorescence enhancement is positively correlated with the added phosphate concentration,and the efficacy of this strategy is demonstrated by a linear phosphate detection range of 5–500µmol/L and a detection limit of 1.06µmol/L.We discuss the interaction between phosphate and Zr in scattering spectrum and MS,respectively.In comparison to phosphate adsorption on Zr-metal organic frameworks(MOFs),where phosphate connects different numbers of cages,both blocking the LMCT effect and causing the cages to aggregate.We also found that the phosphate displaces the ligand from the cage when the phosphate concentration is further expanded,resulting in the formation of new derivatives.This derivative was shown to be useful as a Lewis acid catalyst and as a rare earth ion adsorbent.
