Based on the monthly precipitation and air temperature from 1960 to 1989 in the Luanhe River Basin, the standardized precipitation evapotranspiration index （SPEI） and standardized precipitation index （SPI） at thre...Based on the monthly precipitation and air temperature from 1960 to 1989 in the Luanhe River Basin, the standardized precipitation evapotranspiration index （SPEI） and standardized precipitation index （SPI） at three- and six-month time scales and the self-calibrating Palmer drought severity index （sc-PDSI） were calculated to evaluate droughts in the study area. Temporal variations of the drought severity from 1960 to 1989 were analyzed and compared based on the results of different drought indices, and some typical drought events were identified. Spatial distributions of the drought severity according to the indices were also plotted and investigated. The results reveal the following： the performances of different drought indices are closely associated with the drought duration and the dominant factors of droughts; the SPEI is more accurate than the SPI when both evaporation and precipitation play important roles in drought events; the drought severity shown by the sc-PDSI is generally milder than the actual drought severity from 1960 to 1989; and the evolution of the droughts is usually delayed according to the scPDSI. This study provides valuable references for building drought early warning and mitigation systems in the Luanhe River Basin.展开更多
By anchoring Tb^(3+)ions on its free carboxyl groups of the nanocaged NiMOF,a dual-emission self-calibrating sensor of Tb^(3+)@NiMOF was fabricated through coordination post-synthetic modification(PSM)strategy.With Tb...By anchoring Tb^(3+)ions on its free carboxyl groups of the nanocaged NiMOF,a dual-emission self-calibrating sensor of Tb^(3+)@NiMOF was fabricated through coordination post-synthetic modification(PSM)strategy.With Tb^(3+)ions as the secondary fluorescent signal and sensing active sites,Tb^(3+)@NiMOF presents great potentials in visually and efficiently monitoring EPI in serum,with high sensitivity and selectivity,fast response,excellent recyclable,and the low detection limit(LOD,3.06 ng/mL).Furthermore,a tandem combinational logic gate based intelligent detection system was constructed to improve the practicability and convenience of epinephrine(EPI)detection in serum by comparing the light emitted colour with the series standard colour cards preset in the smartphone.This work provides a promising approach of developing metal-organic frameworks(MOFs)based self-calibrating sensors for intelligent detection of bioactive molecules.展开更多
Incorporation of luminescent moieties into metal-organic frameworks（MOFs） has resulted in numerous photoluminescence（PL） sensors based on chromophore-analyte interactions. However, most of them are only highly sen...Incorporation of luminescent moieties into metal-organic frameworks（MOFs） has resulted in numerous photoluminescence（PL） sensors based on chromophore-analyte interactions. However, most of them are only highly sensitive to few analytes limited by the single luminescent centers in MOFs. To improve the application scopes, dual-emission MOFs were therefore emerged, which can significantly improve the sensitivity by monitoring the relative emission intensity of two luminescent centers. This short review will highlight the recent progress on dual-emission MOFs as highly sensitive sensors for probing of volatile organic molecules（VOMs）, picric acid and peroxynitrite, and as self-calibration PL thermometer.展开更多
An accurate and fast three-step self-calibrating generalized phase-shifting interferomertry(SGPSI) is proposed. In this approach, two new phase-shifting signals are constructed by the difference interferograms normali...An accurate and fast three-step self-calibrating generalized phase-shifting interferomertry(SGPSI) is proposed. In this approach, two new phase-shifting signals are constructed by the difference interferograms normalization and noise suppressing, then the unknown phase shift between the two difference phase-shifting signals is estimated quickly through searching the minimum coefficient of variation of the modulation amplitude, a limited number of pixels are selected to participate in the search process to further save time, and finally the phase is reconstructed through the searched phase shift. Through the reconstruction of phase map by the simulation and experiment, and the comparison with several mature algorithms, the good performance of the proposed algorithm is proved, and it eliminates the limitation of requiring more than three phase-shifting interferograms for high-precision SGPSI. We expect this method to be widely used in the future.展开更多
玉龙雪山及周边地区是典型的季风海洋性冰川区,是研究冰川变化、地-气能量交换、植被群落演替以及生态系统碳水耦合的最重要的区域。水分利用效率(water use efficiency,WUE)是联系生态系统水-碳循环及其与气候因子之间响应关系的重要...玉龙雪山及周边地区是典型的季风海洋性冰川区,是研究冰川变化、地-气能量交换、植被群落演替以及生态系统碳水耦合的最重要的区域。水分利用效率(water use efficiency,WUE)是联系生态系统水-碳循环及其与气候因子之间响应关系的重要参数。本研究利用MODIS卫星遥感总初级生产力(gross primary productivity,GPP)、蒸散发(evapotranspiration,ET)产品和自适应帕尔默干旱指数(self-calibrating Palmer drought severity index,scPDSI)分析了2000—2020年玉龙雪山及周边地区植被WUE空间变化特征,研究了该区GPP、ET、WUE与scPDSI的相关性,探讨了该区不同地貌植被对水分利用及胁迫的适应策略。结果表明:2000—2020年,研究区植被WUE平均值为2.44 g C·m^(-2)·mm^(-1),GPP平均值为1365.0 g C·m^(-2),ET平均值为559.6 mm;WUE平均值最高区域分布在大起伏中山,为2.88 g C·m^(-2)·mm^(-1);最低区域为大起伏极高山,为1.23 g C·m^(-2)·mm^(-1)。玉龙雪山地势起伏大,植被空间分布具有显著垂直地带性特征,植被WUE在3500 m以下区域随海拔上升而增加,3500 m以上则随海拔上升而减少。2000—2020年,研究区逐月WUE呈现增加—减少—增加趋势,不同地貌类型造就了植被WUE变化速率具有显著的差异性特征。玉龙雪山以及周边大起伏高山的植被WUE呈增长趋势,而中海拔平原呈减少趋势。研究区内植被WUE对干旱胁迫响应具有明显的季节性特征,WUE与scPDSI的多年逐月相关性呈现负相关—正相关—负相关—正相关的变化趋势。7月玉龙雪山WUE与scPDSI呈显著正相关,而5月则表现为显著负相关;玉龙雪山周边地区植被WUE与scPDSI在12月—次年6月呈负相关,在7—8月呈正相关。展开更多
基金supported by the National Natural Science Foundation of China(Grant No.41171220)the Program for Changjiang Scholars and Innovative Research Team in University of the Ministry of Education of China(Grant No.IRT13062)+2 种基金the Programme of Introducing Talents of Discipline to Universities(the 111 Project,Grant No.B08048)the Jiangsu Provincial Collaborative Innovation Center for World Water Valley and Water Ecological Civilizationthe National Cooperative Innovation Center for Water Safety and Hydro-Science
文摘Based on the monthly precipitation and air temperature from 1960 to 1989 in the Luanhe River Basin, the standardized precipitation evapotranspiration index （SPEI） and standardized precipitation index （SPI） at three- and six-month time scales and the self-calibrating Palmer drought severity index （sc-PDSI） were calculated to evaluate droughts in the study area. Temporal variations of the drought severity from 1960 to 1989 were analyzed and compared based on the results of different drought indices, and some typical drought events were identified. Spatial distributions of the drought severity according to the indices were also plotted and investigated. The results reveal the following： the performances of different drought indices are closely associated with the drought duration and the dominant factors of droughts; the SPEI is more accurate than the SPI when both evaporation and precipitation play important roles in drought events; the drought severity shown by the sc-PDSI is generally milder than the actual drought severity from 1960 to 1989; and the evolution of the droughts is usually delayed according to the scPDSI. This study provides valuable references for building drought early warning and mitigation systems in the Luanhe River Basin.
基金Project supported by the National Natural Science Foundation of China(21801230,21905255)Natural Science Foundation of Shanxi Province(202203021211090)+2 种基金Young Academic Leader Supported Program of North University of China(QX201904)Shanxi Key Laboratory of Advanced Carbon Electrode Materials(202104010910019)The Key Laboratory Research Foundation of North University of China。
文摘By anchoring Tb^(3+)ions on its free carboxyl groups of the nanocaged NiMOF,a dual-emission self-calibrating sensor of Tb^(3+)@NiMOF was fabricated through coordination post-synthetic modification(PSM)strategy.With Tb^(3+)ions as the secondary fluorescent signal and sensing active sites,Tb^(3+)@NiMOF presents great potentials in visually and efficiently monitoring EPI in serum,with high sensitivity and selectivity,fast response,excellent recyclable,and the low detection limit(LOD,3.06 ng/mL).Furthermore,a tandem combinational logic gate based intelligent detection system was constructed to improve the practicability and convenience of epinephrine(EPI)detection in serum by comparing the light emitted colour with the series standard colour cards preset in the smartphone.This work provides a promising approach of developing metal-organic frameworks(MOFs)based self-calibrating sensors for intelligent detection of bioactive molecules.
基金the financial support of the National Natural Science Foundation of China (Nos. 21373180 and 21525312)the Fundamental Research Funds for the Central Universities (Nos. 2017XZZX001-03A and 2017FZA3007)
文摘Incorporation of luminescent moieties into metal-organic frameworks（MOFs） has resulted in numerous photoluminescence（PL） sensors based on chromophore-analyte interactions. However, most of them are only highly sensitive to few analytes limited by the single luminescent centers in MOFs. To improve the application scopes, dual-emission MOFs were therefore emerged, which can significantly improve the sensitivity by monitoring the relative emission intensity of two luminescent centers. This short review will highlight the recent progress on dual-emission MOFs as highly sensitive sensors for probing of volatile organic molecules（VOMs）, picric acid and peroxynitrite, and as self-calibration PL thermometer.
基金Project supported by the National Natural Science Foundation of China (Grant No. 61905039)Jilin Scientific and Technological Development Program, China (Grant No. 20190701018GH)+1 种基金Education Department of Jilin Province, China (Grant No. JJKH20190691KJ)State Key Laboratory of Applied Optics.
文摘An accurate and fast three-step self-calibrating generalized phase-shifting interferomertry(SGPSI) is proposed. In this approach, two new phase-shifting signals are constructed by the difference interferograms normalization and noise suppressing, then the unknown phase shift between the two difference phase-shifting signals is estimated quickly through searching the minimum coefficient of variation of the modulation amplitude, a limited number of pixels are selected to participate in the search process to further save time, and finally the phase is reconstructed through the searched phase shift. Through the reconstruction of phase map by the simulation and experiment, and the comparison with several mature algorithms, the good performance of the proposed algorithm is proved, and it eliminates the limitation of requiring more than three phase-shifting interferograms for high-precision SGPSI. We expect this method to be widely used in the future.
文摘玉龙雪山及周边地区是典型的季风海洋性冰川区,是研究冰川变化、地-气能量交换、植被群落演替以及生态系统碳水耦合的最重要的区域。水分利用效率(water use efficiency,WUE)是联系生态系统水-碳循环及其与气候因子之间响应关系的重要参数。本研究利用MODIS卫星遥感总初级生产力(gross primary productivity,GPP)、蒸散发(evapotranspiration,ET)产品和自适应帕尔默干旱指数(self-calibrating Palmer drought severity index,scPDSI)分析了2000—2020年玉龙雪山及周边地区植被WUE空间变化特征,研究了该区GPP、ET、WUE与scPDSI的相关性,探讨了该区不同地貌植被对水分利用及胁迫的适应策略。结果表明:2000—2020年,研究区植被WUE平均值为2.44 g C·m^(-2)·mm^(-1),GPP平均值为1365.0 g C·m^(-2),ET平均值为559.6 mm;WUE平均值最高区域分布在大起伏中山,为2.88 g C·m^(-2)·mm^(-1);最低区域为大起伏极高山,为1.23 g C·m^(-2)·mm^(-1)。玉龙雪山地势起伏大,植被空间分布具有显著垂直地带性特征,植被WUE在3500 m以下区域随海拔上升而增加,3500 m以上则随海拔上升而减少。2000—2020年,研究区逐月WUE呈现增加—减少—增加趋势,不同地貌类型造就了植被WUE变化速率具有显著的差异性特征。玉龙雪山以及周边大起伏高山的植被WUE呈增长趋势,而中海拔平原呈减少趋势。研究区内植被WUE对干旱胁迫响应具有明显的季节性特征,WUE与scPDSI的多年逐月相关性呈现负相关—正相关—负相关—正相关的变化趋势。7月玉龙雪山WUE与scPDSI呈显著正相关,而5月则表现为显著负相关;玉龙雪山周边地区植被WUE与scPDSI在12月—次年6月呈负相关,在7—8月呈正相关。
