Metal-organic frameworks(MOFs)and mechanoluminescent(ML)materials have been considered as two types of promising materials that have their own application fields.It would be amazing to endow one material with the adva...Metal-organic frameworks(MOFs)and mechanoluminescent(ML)materials have been considered as two types of promising materials that have their own application fields.It would be amazing to endow one material with the advantages of ML and MOFs,thus broadening their applications.However,there are quite few investigations on this topic,and the ML mechanism in ML-MOFs remains unclear.In this study,we proposed a strategy for developing ML-MOFs by doping lanthanide ions into the non-centrosymmetric SBD([Sr(μ-BDC)(DMF)]∞)MOF,and successfully synthesized a series of lanthanide-doped MOFs Ln-SBD(Ln=Tb,Dy,Sm,Eu)and Tb1-xEux-SBD(x=0.2,0.4,0.6,0.8)with multicolor ML.The lanthanide ions were uniformly distributed in the matrix of the SBD-MOF,and occupied the Sr site.The MLMOFs exhibited intense multicolor ML emissions varying from green to yellow to red by changing the co-doping ratios and species of lanthanide ions.The similar ML and photoluminescence(PL)spectra indicated that the ML emission was assigned to the radiative transition from the excited states to the ground states of lanthanide ions.The radiative transition was induced by the electron bombardment process that originated from the piezoelectric effect of the non-centrosymmetric SBD host.In addition,a pioneering temperature sensing research based on ML was carried out,which is promising for realizing dual-functional detection of stress and temperature without excitation light sources.This study gives a unique insight for developing more versatile and interesting smart materials by combining the versatility of MOF with the ML emission,imparting additional values to both MOF and ML materials.Moreover,this study provides a general rule for selecting MOFs with an acentric structure as the host for ML materials.展开更多
The purpose of this paper is to explore the trade-offs and synergies of multifunctional cultivated land(MCL) at multiple scales. The study area is Wuhan Metropolitan Area, China. The entropy method and the method of S...The purpose of this paper is to explore the trade-offs and synergies of multifunctional cultivated land(MCL) at multiple scales. The study area is Wuhan Metropolitan Area, China. The entropy method and the method of Spearman’s rank correlation were employed for the analysis of combined land use/cover data, administrative division data, population data and statistical yearbook data, from the multi-scale perspectives of cities, counties and townships. The results showed that:(1) The multi-functionality of cultivated land had obvious spatial differences and its overall spatial patterns were relatively robust, which did not change very much at the single scale.(2) At each single scale, the MCL’s trade-offs and synergies had spatial heterogeneity.(3) Scale effects existed in the MCL’s trade-offs and synergies. From the prefecture-level city scale, to the county scale, and to the township scale, the MCL’s trade-offs were changed to synergies, and some synergic relationships were enhanced. This article contributes to the literature by deepening the multiscale analysis of trade-offs and synergies of multifunctional cultivated land. The conclusions might provide a basis for helping policy-makers to implement protection measures for the multi-functionality of cultivated land at the right spatial scale, and to promote the higher-level synergies of multifunctional cultivated land to realize its sustainable use.展开更多
基金the National Natural Science Foundation of China(51832005)。
文摘Metal-organic frameworks(MOFs)and mechanoluminescent(ML)materials have been considered as two types of promising materials that have their own application fields.It would be amazing to endow one material with the advantages of ML and MOFs,thus broadening their applications.However,there are quite few investigations on this topic,and the ML mechanism in ML-MOFs remains unclear.In this study,we proposed a strategy for developing ML-MOFs by doping lanthanide ions into the non-centrosymmetric SBD([Sr(μ-BDC)(DMF)]∞)MOF,and successfully synthesized a series of lanthanide-doped MOFs Ln-SBD(Ln=Tb,Dy,Sm,Eu)and Tb1-xEux-SBD(x=0.2,0.4,0.6,0.8)with multicolor ML.The lanthanide ions were uniformly distributed in the matrix of the SBD-MOF,and occupied the Sr site.The MLMOFs exhibited intense multicolor ML emissions varying from green to yellow to red by changing the co-doping ratios and species of lanthanide ions.The similar ML and photoluminescence(PL)spectra indicated that the ML emission was assigned to the radiative transition from the excited states to the ground states of lanthanide ions.The radiative transition was induced by the electron bombardment process that originated from the piezoelectric effect of the non-centrosymmetric SBD host.In addition,a pioneering temperature sensing research based on ML was carried out,which is promising for realizing dual-functional detection of stress and temperature without excitation light sources.This study gives a unique insight for developing more versatile and interesting smart materials by combining the versatility of MOF with the ML emission,imparting additional values to both MOF and ML materials.Moreover,this study provides a general rule for selecting MOFs with an acentric structure as the host for ML materials.
基金The National Natural Science Foundation of China (71673105)The Fundamental Research Funds for the Central Universities (2662016PY116)。
文摘The purpose of this paper is to explore the trade-offs and synergies of multifunctional cultivated land(MCL) at multiple scales. The study area is Wuhan Metropolitan Area, China. The entropy method and the method of Spearman’s rank correlation were employed for the analysis of combined land use/cover data, administrative division data, population data and statistical yearbook data, from the multi-scale perspectives of cities, counties and townships. The results showed that:(1) The multi-functionality of cultivated land had obvious spatial differences and its overall spatial patterns were relatively robust, which did not change very much at the single scale.(2) At each single scale, the MCL’s trade-offs and synergies had spatial heterogeneity.(3) Scale effects existed in the MCL’s trade-offs and synergies. From the prefecture-level city scale, to the county scale, and to the township scale, the MCL’s trade-offs were changed to synergies, and some synergic relationships were enhanced. This article contributes to the literature by deepening the multiscale analysis of trade-offs and synergies of multifunctional cultivated land. The conclusions might provide a basis for helping policy-makers to implement protection measures for the multi-functionality of cultivated land at the right spatial scale, and to promote the higher-level synergies of multifunctional cultivated land to realize its sustainable use.
