Mineral structure-stimulated material design has made great success in the development of excellent phosphor materials.Herein,spinel-type oxides Mg_(4)Ga_(1−y)Al_(y)SbO_(8)(MGA_(y)SO)with a double 2:1 ordering of Mg/(...Mineral structure-stimulated material design has made great success in the development of excellent phosphor materials.Herein,spinel-type oxides Mg_(4)Ga_(1−y)Al_(y)SbO_(8)(MGA_(y)SO)with a double 2:1 ordering of Mg/(Ga/Al)and Mg/Sb cations in tetrahedral and octahedral sublattices,respectively,were rationally designed and structurally characterized by combined Rietveld refinements against high-resolution X-ray powder diffraction(XRPD)data and neutron powder diffraction(NPD)data.A joint hybrid density functional theory(DFT)calculation and crystal orbital Hamilton population(COHP)analysis demonstrated that these new spinels are direct semiconductors with band gap values increasing along with the Al^(3+)content due to the lift of anti-bonding states from the Sb_(2)–O pairs.Mn-activated MGSO exhibited dual emissions from multiple green-emitting Mn^(2+)and red-emitting Mn^(4+)activators due to the facile occurrence of Mn^(4+)-to-Mn^(2+)self-reduction,which is inevitable in Mn-doped spinel-type phosphors.This self-reduction can be effectively inhibited by the site-selective Al^(3+)-to-Ga^(3+)substitution in MGA_(y)SO:Mn^(2+/4+),thereby resulting in an accumulation of Mn ions in the octahedrally coordinated sites and a tunable emission colour from green to yellow and then to deep-red.Interestingly,Mn^(2+)green emissions presented excellent anti-thermal quenching(165.4%at 463 K)in a very wide temperature range(303–463 K),whereas severe thermal quenching was observed for the Mn^(4+)red emissions.This distinctive thermal response could be applied in temperature sensing,as demonstrated by a high relative sensitivity(S_(r))of 1.22%K^(-1)at room temperature(303 K),which is superior to many reported optical thermometry materials.Our findings not only offer structural insight into new doubly ordered spinels,but also provide an effective strategy for regulating the valence states of Mn ions for potential application in light-emitting diodes and temperature sensing.展开更多
The sediment samples (including various layers) obtained from 12 stations, 35 Mn nodule samples from 16 stations and water body samples were collected during Mn nodule investigation made in the Pacific Ocean in summer...The sediment samples (including various layers) obtained from 12 stations, 35 Mn nodule samples from 16 stations and water body samples were collected during Mn nodule investigation made in the Pacific Ocean in summer, 1983. The coexisting, separating and accumulating regularities and their relation concerning the formation of Mn nodules are approached through the distribution and partition characteristics of Mn and Fe combined with the data from nearshore area in the East China Sea continental shelf.展开更多
Wheat grown in Mn-deficient soil has been widely observed to produce much reduced yields. Breeding for Mn-efficient wheat genotypes adapted to Mn-deficient soils would represent a long-term solution for wheat agronomy...Wheat grown in Mn-deficient soil has been widely observed to produce much reduced yields. Breeding for Mn-efficient wheat genotypes adapted to Mn-deficient soils would represent a long-term solution for wheat agronomy. To characterize the physiological basis of Mn efficiency in wheat genotypes would facilitate the breeding programs for producing Mn-efficient wheat. Using a solution culture and a soil culture system in the present study, a Mn-efficient UK wheat genotype Maris Butler and a Mn-inefficient UK wheat genotype Paragon have been compared with a Mn-efficient Australian wheat genotype C8MM in the responses to Mn deficiency in order to characterize the Mn efficiency in these wheat genotypes. Results showed that in solution culture, Marls Butler grown under Mn deficiency had 77% relative dry matter yield of control plants that were grown under Mn sufficiency, whereas CSMM and Paragon had 60% and 58% relative dry matter yield of their respective controls. Results from the soil culture demonstrated that relative dry matter yield remained high for Maris Butler and C8MM （53% and 56%, respectively）, whereas the value for Paragon dropped to 33%. In terms of dry matter yield and photosynthetic efficiency, Maris Butler demonstrated Mn efficiency in both solution culture and soil culture, whereas C8MM showed Mn efficiency only in soil culture. Results also demonstrated that under Mn-depleted supply in soil, plants of C8MM had a significantly higher ability in Mn uptake, whereas plants of Marls Butler showed a higher internal Mn use efficiency in comparison with plants of Paragon. Results from the present study indicate that the ability of C8MM to accumulate higher amounts of Mn is the basis of the improved Mn efficiency of this genotype in comparison with Paragon, and in Marls Butler there is a higher internal use of Mn expressed as an improved photosynthetic efficiency in conferring its Mn efficiency. It is suggested that more than one mechanism has arisen in wheat to confer tolerance to Mn deficiency.展开更多
基金National Natural Science Foundation of China(no.22271030 and 22171032)Natural Science Foundation of Chongqing(cstc2021jcyj-msxmX0971)。
文摘Mineral structure-stimulated material design has made great success in the development of excellent phosphor materials.Herein,spinel-type oxides Mg_(4)Ga_(1−y)Al_(y)SbO_(8)(MGA_(y)SO)with a double 2:1 ordering of Mg/(Ga/Al)and Mg/Sb cations in tetrahedral and octahedral sublattices,respectively,were rationally designed and structurally characterized by combined Rietveld refinements against high-resolution X-ray powder diffraction(XRPD)data and neutron powder diffraction(NPD)data.A joint hybrid density functional theory(DFT)calculation and crystal orbital Hamilton population(COHP)analysis demonstrated that these new spinels are direct semiconductors with band gap values increasing along with the Al^(3+)content due to the lift of anti-bonding states from the Sb_(2)–O pairs.Mn-activated MGSO exhibited dual emissions from multiple green-emitting Mn^(2+)and red-emitting Mn^(4+)activators due to the facile occurrence of Mn^(4+)-to-Mn^(2+)self-reduction,which is inevitable in Mn-doped spinel-type phosphors.This self-reduction can be effectively inhibited by the site-selective Al^(3+)-to-Ga^(3+)substitution in MGA_(y)SO:Mn^(2+/4+),thereby resulting in an accumulation of Mn ions in the octahedrally coordinated sites and a tunable emission colour from green to yellow and then to deep-red.Interestingly,Mn^(2+)green emissions presented excellent anti-thermal quenching(165.4%at 463 K)in a very wide temperature range(303–463 K),whereas severe thermal quenching was observed for the Mn^(4+)red emissions.This distinctive thermal response could be applied in temperature sensing,as demonstrated by a high relative sensitivity(S_(r))of 1.22%K^(-1)at room temperature(303 K),which is superior to many reported optical thermometry materials.Our findings not only offer structural insight into new doubly ordered spinels,but also provide an effective strategy for regulating the valence states of Mn ions for potential application in light-emitting diodes and temperature sensing.
文摘The sediment samples (including various layers) obtained from 12 stations, 35 Mn nodule samples from 16 stations and water body samples were collected during Mn nodule investigation made in the Pacific Ocean in summer, 1983. The coexisting, separating and accumulating regularities and their relation concerning the formation of Mn nodules are approached through the distribution and partition characteristics of Mn and Fe combined with the data from nearshore area in the East China Sea continental shelf.
文摘Wheat grown in Mn-deficient soil has been widely observed to produce much reduced yields. Breeding for Mn-efficient wheat genotypes adapted to Mn-deficient soils would represent a long-term solution for wheat agronomy. To characterize the physiological basis of Mn efficiency in wheat genotypes would facilitate the breeding programs for producing Mn-efficient wheat. Using a solution culture and a soil culture system in the present study, a Mn-efficient UK wheat genotype Maris Butler and a Mn-inefficient UK wheat genotype Paragon have been compared with a Mn-efficient Australian wheat genotype C8MM in the responses to Mn deficiency in order to characterize the Mn efficiency in these wheat genotypes. Results showed that in solution culture, Marls Butler grown under Mn deficiency had 77% relative dry matter yield of control plants that were grown under Mn sufficiency, whereas CSMM and Paragon had 60% and 58% relative dry matter yield of their respective controls. Results from the soil culture demonstrated that relative dry matter yield remained high for Maris Butler and C8MM （53% and 56%, respectively）, whereas the value for Paragon dropped to 33%. In terms of dry matter yield and photosynthetic efficiency, Maris Butler demonstrated Mn efficiency in both solution culture and soil culture, whereas C8MM showed Mn efficiency only in soil culture. Results also demonstrated that under Mn-depleted supply in soil, plants of C8MM had a significantly higher ability in Mn uptake, whereas plants of Marls Butler showed a higher internal Mn use efficiency in comparison with plants of Paragon. Results from the present study indicate that the ability of C8MM to accumulate higher amounts of Mn is the basis of the improved Mn efficiency of this genotype in comparison with Paragon, and in Marls Butler there is a higher internal use of Mn expressed as an improved photosynthetic efficiency in conferring its Mn efficiency. It is suggested that more than one mechanism has arisen in wheat to confer tolerance to Mn deficiency.
