This paper outlines effective methods for selecting and breeding maize varieties,with a focus on early and late hybridization,superior line re-selection,multi-part selection,and other techniques.The goal is to facilit...This paper outlines effective methods for selecting and breeding maize varieties,with a focus on early and late hybridization,superior line re-selection,multi-part selection,and other techniques.The goal is to facilitate the innovation of northern spring-sown maize germplasm resources,the selection and breeding of new varieties,thereby contributing to food security in China.展开更多
The unique luminescent performance of lanthanide complexes/clay minerals hybrid materials has been fascinating many researchers for recent decades.It not only retains the excellent luminescent characteristics of lanth...The unique luminescent performance of lanthanide complexes/clay minerals hybrid materials has been fascinating many researchers for recent decades.It not only retains the excellent luminescent characteristics of lanthanide complexes but also improves the poor stability of the complexes.In this article,we introduce the luminescence mechanism of lanthanide complexes and point out the necessity of their combination with clay minerals.After the analysis of the structure and interlayer environment differences of 1:1-type and 2:1-type clay minerals,the intercalation methods(covalent grafting and ion exchange)appropriate for different clay minerals are summarized with examples.Based on the luminescence characteristics of the hybrid materials,the applications of these materials as luminescent probes in recognition of specific metal cations and molecules,detection of pH value,and temperature are reviewed.Finally,the current problems in the preparation of lanthanide complexes/clay minerals hybrid luminescent materials and shortcomings that need improvement in their performance are analyzed,and the application prospect is forecast.展开更多
Tb^(3+),Dy^(3+)-co-doped Ca_(9)Tb_(x)Dy_(1-x)(PO_(4))_(5)(SiO_(4))F_(2) phosphors were prepared via high-temperature solidphase reaction method and the potential application in optical temperature measurements due to ...Tb^(3+),Dy^(3+)-co-doped Ca_(9)Tb_(x)Dy_(1-x)(PO_(4))_(5)(SiO_(4))F_(2) phosphors were prepared via high-temperature solidphase reaction method and the potential application in optical temperature measurements due to their color-tunable property was investigated in detail.The photoluminescence emission(PL) and photoluminescence excitation(PLE) spectra results show that the as-prepared phosphors exhibit both Tb^(3+) and Dy^(3+) emissions at 546 nm(^(5)D_(4)-^(7)F_(5) transition of Tb^(3+)) and 587 nm(^(4)F_(9/2)-^(6)H_(13/2) transition of Dy^(3+)) upon 376 nm excitation,respectively.In addition,the fluorescence decay analysis shows that the lifetime of the Tb3+emission rapidly decreases,which confirms the energy transfer existence between Dy^(3+) and Tb^(3+).Under 376 nm excitation,the temperature dependence of the fluorescence intensity ratios for the dualmission bands peaked at 546 and 587 nm was studied in the temperature range from 303 to 573 K.The results show that with the increase of Dy^(3+) concentration,the relative sensitivity first increases and then decreases,what’s more,the maximum relative sensitivity is 3.142×10^(-3)%/K for Ca_(9)Tb_(x)Dy_(1-x)(PO_(4))_(5)(SiO_(4))F_(2)(x=0.4).As a consequence,this preliminary study provides a novel method for exploring the novel thermo meters.展开更多
At present,the rare earth(RE) ions doped phosphors have attracted more and more attention because of their excellent properties.In this paper,a series of novel blue-purple β-Ca_(3)(PO_(4))_(2):Ce^(3+) phosphors were ...At present,the rare earth(RE) ions doped phosphors have attracted more and more attention because of their excellent properties.In this paper,a series of novel blue-purple β-Ca_(3)(PO_(4))_(2):Ce^(3+) phosphors were synthesized by a high temperature solid phase method.The X-ray diffraction(XRD),infrared spectrum,energy dispersive spectroscopy(EDS),scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS),photoluminescence excitation and emission spectra were used to investigate the crystal structure,composition and the luminescent properties of the resulting samples.The phosphor shows a strong absorption in the ultraviolet band.Under the excitation of 269 nm,the phosphor emits a strong purple fluorescence ranging from 360 to 520 nm.When Ce^(3+) doping content is 0.07 mol,the strongest luminescence intensity is reached,and the concentration quenching mechanism is dipole-dipole(d-d)interaction for Ce^(3+) based on Dexter theory.展开更多
To meet the growing demand for stable dual-emission phosphors for use in optoelectronic applications,this study investigated a self-reduction strategy with Mn-doped LizZnGe:Og(LZGO)phosphors.The spinel-structured LZGO...To meet the growing demand for stable dual-emission phosphors for use in optoelectronic applications,this study investigated a self-reduction strategy with Mn-doped LizZnGe:Og(LZGO)phosphors.The spinel-structured LZGO lattice enables the coexistence of Mn2 and Mn*t via oxygen vacancies and lattice defects,achieving visible(Vis)and near-infrared(NiR)dual emission without the need for external reducing agents.Spectroscopic analyses,including X-ray photoelectron spectroscopy(XPS)and diffuse reflectance spectroscopy(DRS),confirmed the presence of heterovalent Mn states,with lifetimes of 3.63 ms(Mn?+)and 0.32 ms(Mn*t)under selective excitation.The LZGO:xMn system thus demonstrates excitation-tunable Vis-NIR luminescence and high stability,making it a cost-effective and environmentally friendly candidate for anticounterfeiting and bioimaging applications.This work presents a defect engineering-driven design concept for developing multifunctional redox-activephosphors withbroad application prospects.展开更多
Advancing sustainable hydrogen production relies on the creation of effective electrocatalysts for the hydrogen evolution reaction(HER).Ruthenium(Ru)is a potential alternative to platinum due to its lower cost and hig...Advancing sustainable hydrogen production relies on the creation of effective electrocatalysts for the hydrogen evolution reaction(HER).Ruthenium(Ru)is a potential alternative to platinum due to its lower cost and high activity,yet its performance in alkaline HER remains limited by sluggish reaction kinetics.Herein,we propose a strategy to modulate electronic asymmetry within Ru clusters by anchoring Ru nanoclusters on N-doped graphene(Ru-NC),optimizing the charge distribution between high-valent Run+and metallic Ru0 sites.The Ru-NC catalyst,having a Ruⁿ+/Ru0 ratio of 57.1%,demonstrates superior HER activity with an overpotential of merely 29 mV at 10 mA·cm^(-2)and a Tafel slope of 46 mV·dec^(-1)in 1.0 M KOH,surpassing the performance of Pt/C catalyst.Experimental and structural analyses reveal that the asymmetric electronic configuration facilitates H_(2)O dissociation at Run+sites and efficient H adsorption/desorption at Ru0 sites,synergistically lowering energy barriers for HER intermediates.Furthermore,Ru-NC demonstrates remarkable stability,retaining its activity after 5000 cycles and operating continuously for 80 h at 100 mA·cm^(-2)with minimal degradation.This work highlights the pivotal role of electronic asymmetry in enhancing HER kinetics and provides a rational design principle for high-performance Ru-based electrocatalysts.展开更多
The distance effect of the doped heteroatoms away from the catalytic centers has rarely been reported.In this work,we conducted density functional theory calculations to thoroughly investigate the influence of heteroa...The distance effect of the doped heteroatoms away from the catalytic centers has rarely been reported.In this work,we conducted density functional theory calculations to thoroughly investigate the influence of heteroatom(N,P,B,and S atoms)doping distance on the oxygen reduction reaction(ORR)activity of graphene-based FeN_(4)sites.We uncovered a Sabatier-like relationship between heteroatom doping distance and ORR activity of FeN_(4)sites.The nearest doping does not significantly improve and even block the ORR activity of FeN_(4)sites.Optimal ORR activity is achieved when the heteroatoms are 4-5Å(N,P,and S atoms)or 6-7Å(B atoms)away from the Fe atoms.Analysis of electronic structure indicates that distance effect can modulate the local chemical environment of Fe atoms,thereby account for the changes in ORR activity along with the doping distance and doping atoms.This study provides insights into the influence of heteroatom doping on the chemical environment of reaction active centers,and provides the theoretical guidance for controlling the doping distance of heteroatoms to achieve optimal catalytic activity and selectivity.展开更多
文摘This paper outlines effective methods for selecting and breeding maize varieties,with a focus on early and late hybridization,superior line re-selection,multi-part selection,and other techniques.The goal is to facilitate the innovation of northern spring-sown maize germplasm resources,the selection and breeding of new varieties,thereby contributing to food security in China.
基金Project supported by the National Natural Science Foundation of China(51872269,42072053)。
文摘The unique luminescent performance of lanthanide complexes/clay minerals hybrid materials has been fascinating many researchers for recent decades.It not only retains the excellent luminescent characteristics of lanthanide complexes but also improves the poor stability of the complexes.In this article,we introduce the luminescence mechanism of lanthanide complexes and point out the necessity of their combination with clay minerals.After the analysis of the structure and interlayer environment differences of 1:1-type and 2:1-type clay minerals,the intercalation methods(covalent grafting and ion exchange)appropriate for different clay minerals are summarized with examples.Based on the luminescence characteristics of the hybrid materials,the applications of these materials as luminescent probes in recognition of specific metal cations and molecules,detection of pH value,and temperature are reviewed.Finally,the current problems in the preparation of lanthanide complexes/clay minerals hybrid luminescent materials and shortcomings that need improvement in their performance are analyzed,and the application prospect is forecast.
基金the National Natural Science Foundations of China(51872269,51672257)the Fundamental Research Fund for the Central Universities(2652019132)Guangdong Innovation Research Team for Higher Education(2017KCXTD030)。
文摘Tb^(3+),Dy^(3+)-co-doped Ca_(9)Tb_(x)Dy_(1-x)(PO_(4))_(5)(SiO_(4))F_(2) phosphors were prepared via high-temperature solidphase reaction method and the potential application in optical temperature measurements due to their color-tunable property was investigated in detail.The photoluminescence emission(PL) and photoluminescence excitation(PLE) spectra results show that the as-prepared phosphors exhibit both Tb^(3+) and Dy^(3+) emissions at 546 nm(^(5)D_(4)-^(7)F_(5) transition of Tb^(3+)) and 587 nm(^(4)F_(9/2)-^(6)H_(13/2) transition of Dy^(3+)) upon 376 nm excitation,respectively.In addition,the fluorescence decay analysis shows that the lifetime of the Tb3+emission rapidly decreases,which confirms the energy transfer existence between Dy^(3+) and Tb^(3+).Under 376 nm excitation,the temperature dependence of the fluorescence intensity ratios for the dualmission bands peaked at 546 and 587 nm was studied in the temperature range from 303 to 573 K.The results show that with the increase of Dy^(3+) concentration,the relative sensitivity first increases and then decreases,what’s more,the maximum relative sensitivity is 3.142×10^(-3)%/K for Ca_(9)Tb_(x)Dy_(1-x)(PO_(4))_(5)(SiO_(4))F_(2)(x=0.4).As a consequence,this preliminary study provides a novel method for exploring the novel thermo meters.
基金Project supported by the National Natural Science Foundation of China(41802040)China Postdoctoral International Exchange Program(2019.92)。
文摘At present,the rare earth(RE) ions doped phosphors have attracted more and more attention because of their excellent properties.In this paper,a series of novel blue-purple β-Ca_(3)(PO_(4))_(2):Ce^(3+) phosphors were synthesized by a high temperature solid phase method.The X-ray diffraction(XRD),infrared spectrum,energy dispersive spectroscopy(EDS),scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS),photoluminescence excitation and emission spectra were used to investigate the crystal structure,composition and the luminescent properties of the resulting samples.The phosphor shows a strong absorption in the ultraviolet band.Under the excitation of 269 nm,the phosphor emits a strong purple fluorescence ranging from 360 to 520 nm.When Ce^(3+) doping content is 0.07 mol,the strongest luminescence intensity is reached,and the concentration quenching mechanism is dipole-dipole(d-d)interaction for Ce^(3+) based on Dexter theory.
基金supported by the National Natural Science Foundation of China(Grant No.52274273)the High Performance Computing Platform Project of China University of Geosciences(Beijing)+1 种基金the Key Research and Development Projects of Xinjiang Uygur Autonomous Region(Grant Nos.2022B02033-3 and 2022B02049-3-3)the Xinjiang"Tianshan talent plan"project(Grant No.2021061).
文摘To meet the growing demand for stable dual-emission phosphors for use in optoelectronic applications,this study investigated a self-reduction strategy with Mn-doped LizZnGe:Og(LZGO)phosphors.The spinel-structured LZGO lattice enables the coexistence of Mn2 and Mn*t via oxygen vacancies and lattice defects,achieving visible(Vis)and near-infrared(NiR)dual emission without the need for external reducing agents.Spectroscopic analyses,including X-ray photoelectron spectroscopy(XPS)and diffuse reflectance spectroscopy(DRS),confirmed the presence of heterovalent Mn states,with lifetimes of 3.63 ms(Mn?+)and 0.32 ms(Mn*t)under selective excitation.The LZGO:xMn system thus demonstrates excitation-tunable Vis-NIR luminescence and high stability,making it a cost-effective and environmentally friendly candidate for anticounterfeiting and bioimaging applications.This work presents a defect engineering-driven design concept for developing multifunctional redox-activephosphors withbroad application prospects.
基金supported by the National Natural Science Foundation of China(No.22403074)and Key Research and Development Program of Shaanxi Province(No.2025SF-YBXM-526)Y.Q.S.acknowledges the“Major Science and Technology Projects”of Yunnan Province(No.202302AB080019-4)the“Young Talent Support Plan”of Xi'an Jiaotong University.Supercomputing facilities were provided by Computing Center in Xi'an and Hefei Advanced Computing Center.
文摘Advancing sustainable hydrogen production relies on the creation of effective electrocatalysts for the hydrogen evolution reaction(HER).Ruthenium(Ru)is a potential alternative to platinum due to its lower cost and high activity,yet its performance in alkaline HER remains limited by sluggish reaction kinetics.Herein,we propose a strategy to modulate electronic asymmetry within Ru clusters by anchoring Ru nanoclusters on N-doped graphene(Ru-NC),optimizing the charge distribution between high-valent Run+and metallic Ru0 sites.The Ru-NC catalyst,having a Ruⁿ+/Ru0 ratio of 57.1%,demonstrates superior HER activity with an overpotential of merely 29 mV at 10 mA·cm^(-2)and a Tafel slope of 46 mV·dec^(-1)in 1.0 M KOH,surpassing the performance of Pt/C catalyst.Experimental and structural analyses reveal that the asymmetric electronic configuration facilitates H_(2)O dissociation at Run+sites and efficient H adsorption/desorption at Ru0 sites,synergistically lowering energy barriers for HER intermediates.Furthermore,Ru-NC demonstrates remarkable stability,retaining its activity after 5000 cycles and operating continuously for 80 h at 100 mA·cm^(-2)with minimal degradation.This work highlights the pivotal role of electronic asymmetry in enhancing HER kinetics and provides a rational design principle for high-performance Ru-based electrocatalysts.
文摘The distance effect of the doped heteroatoms away from the catalytic centers has rarely been reported.In this work,we conducted density functional theory calculations to thoroughly investigate the influence of heteroatom(N,P,B,and S atoms)doping distance on the oxygen reduction reaction(ORR)activity of graphene-based FeN_(4)sites.We uncovered a Sabatier-like relationship between heteroatom doping distance and ORR activity of FeN_(4)sites.The nearest doping does not significantly improve and even block the ORR activity of FeN_(4)sites.Optimal ORR activity is achieved when the heteroatoms are 4-5Å(N,P,and S atoms)or 6-7Å(B atoms)away from the Fe atoms.Analysis of electronic structure indicates that distance effect can modulate the local chemical environment of Fe atoms,thereby account for the changes in ORR activity along with the doping distance and doping atoms.This study provides insights into the influence of heteroatom doping on the chemical environment of reaction active centers,and provides the theoretical guidance for controlling the doping distance of heteroatoms to achieve optimal catalytic activity and selectivity.
