A thulium-doped fiber amplifier-enhanced photoacoustic spectroscopy(TDFE-PAS) sensor was developed for carbon dioxide(CO_(2)) detection utilizing a 2004 nm distributed feedback(DFB) laser. The thulium-doped fiber was ...A thulium-doped fiber amplifier-enhanced photoacoustic spectroscopy(TDFE-PAS) sensor was developed for carbon dioxide(CO_(2)) detection utilizing a 2004 nm distributed feedback(DFB) laser. The thulium-doped fiber was in-band pumped by a1567 nm source to amplify the optical power of 2004 nm to enhance the photoacoustic excitation. As a result, the photoacoustic signal was enhanced over 101 times. Based on a 7.9 mL differential PA cell, the sensor achieved a linearity of R^(2)= 0.9997 on CO_(2)detection in a wide concentration range of 0–10,000 ppm(part per million). The noise equivalent detection limit was evaluated to be 190 ppb(part per billion) at a response time of 10 s.展开更多
The agricultural land-use system(ALUS)is a complex and coupled system centered on land use,which includes all human activities and their outcomes in utilizing agricultural land.With the emergence of issues such as cli...The agricultural land-use system(ALUS)is a complex and coupled system centered on land use,which includes all human activities and their outcomes in utilizing agricultural land.With the emergence of issues such as climate change and food security,the land human coupling system has received widespread attention from scholars.Therefore,it is crucial to establish an ALUS management mechanism that sustainably utilizes resources,sequesters carbon,and reduces emissions while steadily improving food production.In this study,progresses are clarified in the theoretical framework and methods of ALUS management,including relevant research about agricultural land-use carbon emissions and management in the context of climate change,evaluation of the resource carrying capacity of a ALUS for food security,and layout optimization of agricultural land to improve land use capacity.It is crucial to fully leverage the role of ALUS in addressing climate change,ensuring nutrition and food security,providing ecosystem services,and promoting sustainable environmental development.However,the theoretical and empirical research on ALUS in China started relatively late.In this context,there is an urgent need to establish a better management system to accelerate the transformation of sustainable use of agricultural land in China,support high-quality development and ecological civilization.展开更多
基金supported by the National Natural Science Foundation of China (Nos. 52001295 and 62375262)the Natural Science Foundation of Shandong Province (No. ZR2020QF097)。
文摘A thulium-doped fiber amplifier-enhanced photoacoustic spectroscopy(TDFE-PAS) sensor was developed for carbon dioxide(CO_(2)) detection utilizing a 2004 nm distributed feedback(DFB) laser. The thulium-doped fiber was in-band pumped by a1567 nm source to amplify the optical power of 2004 nm to enhance the photoacoustic excitation. As a result, the photoacoustic signal was enhanced over 101 times. Based on a 7.9 mL differential PA cell, the sensor achieved a linearity of R^(2)= 0.9997 on CO_(2)detection in a wide concentration range of 0–10,000 ppm(part per million). The noise equivalent detection limit was evaluated to be 190 ppb(part per billion) at a response time of 10 s.
基金supported by grants from the National Natural Science Foundation of China(72221002).
文摘The agricultural land-use system(ALUS)is a complex and coupled system centered on land use,which includes all human activities and their outcomes in utilizing agricultural land.With the emergence of issues such as climate change and food security,the land human coupling system has received widespread attention from scholars.Therefore,it is crucial to establish an ALUS management mechanism that sustainably utilizes resources,sequesters carbon,and reduces emissions while steadily improving food production.In this study,progresses are clarified in the theoretical framework and methods of ALUS management,including relevant research about agricultural land-use carbon emissions and management in the context of climate change,evaluation of the resource carrying capacity of a ALUS for food security,and layout optimization of agricultural land to improve land use capacity.It is crucial to fully leverage the role of ALUS in addressing climate change,ensuring nutrition and food security,providing ecosystem services,and promoting sustainable environmental development.However,the theoretical and empirical research on ALUS in China started relatively late.In this context,there is an urgent need to establish a better management system to accelerate the transformation of sustainable use of agricultural land in China,support high-quality development and ecological civilization.
