Direct separation of Xe and Kr from air or used nuclear fuel(UNF)off-gas by means of porous adsorbents is of industrial importance but is a very challenging task.In this work,we show a robust metal-organic framework(M...Direct separation of Xe and Kr from air or used nuclear fuel(UNF)off-gas by means of porous adsorbents is of industrial importance but is a very challenging task.In this work,we show a robust metal-organic framework(MOF),namely ECUT-60,which renders not only high chemical stability,but also unique structure with multiple traps.This leads to the ultrahigh Xe adsorption capacity,exceeding most reported porous materials.Impressively,this MOF also enables high selectivity of Xe over Kr,CO2,O2,and N2,leading to the high-performance separation for trace quantitites of Xe/Kr from a simulated UNF reprocessing off-gas.The separation capability has been demonstrated by using dynamic breakthrough experiments,giving the record Xe uptake up to 70.4 mmol/kg and the production of 19.7 mmol/kg pure Xe.Consequently,ECUT-60 has promising potential in direct production of Xe from UNF off-gas or air.The separation mechanism,as unveiled by theoretical calculation,is attributed to the multiple traps in ECUT-60 that affords rigid restrict for Xe atom via van der Waals force.展开更多
The loss rate of cold atoms in a trap due to residual gas collisions differs from that in a free state after the cold atoms are released from the trap. In this paper, the loss rate in a cold rubidium-87 atom cloud was...The loss rate of cold atoms in a trap due to residual gas collisions differs from that in a free state after the cold atoms are released from the trap. In this paper, the loss rate in a cold rubidium-87 atom cloud was measured in a magneto-optical trap （MOT） and during its free flight. The residual gas pressure was analyzed by a residual gas analyzer, and the pressure distribution in a vacuum chamber was numerically calculated by the angular coefficient method. The decay factor, which describes the decay behavior of cold atoms due to residual gas collisions during a free flight, was calculated. It was found that the decay factor agrees well with theoretical predictions under various vacuum conditions.展开更多
By the end of 2019,more than 220 gas fields had been discovered in the South China Sea.In order to accurately determine the geological characteristics of the large-and medium-sized gas fields in the South China Sea,th...By the end of 2019,more than 220 gas fields had been discovered in the South China Sea.In order to accurately determine the geological characteristics of the large-and medium-sized gas fields in the South China Sea,this study conducted a comprehensive examination of the gas fields.Based on the abundant available geologic and geochemical data,the distribution and key controlling factors of the hydrocarbon accumulation in the South China Sea were analyzed.The geological and geochemical features of the gas fields were as follows:(1)the gas fields were distributed similar to beads in the shape of a"C"along the northern,western,and southern continental margins;(2)the natural gas in the region was determined to be composed of higher amounts of alkane gas and less CO2;(3)the majority of the alkane gas was observed to be coal-type gas;(4)the gas reservoir types included structural reservoirs,lithologic reservoirs,and stratigraphic reservoirs,respectively;(5)the reservoir ages were mainly Oligocene,Miocene,and Pliocene,while the lithology was mainly organic reef,with some sandstone deposits;and(6)the main hydrocarbon accumulation period for the region was determined to be the late Pliocene-Quaternary Period.In addition,the main controlling factors of the gas reservoirs were confirmed to have been the development of coal measures,sufficient thermal evolution,and favorable migration and accumulation conditions.展开更多
Developing high sensitive organic semiconductors(OSCs)in organic thin-film transistors(OTFTs)is the key for OTFT based gas sensors.Herein,we report a simple processing route of highly sensitive OSCs for high performan...Developing high sensitive organic semiconductors(OSCs)in organic thin-film transistors(OTFTs)is the key for OTFT based gas sensors.Herein,we report a simple processing route of highly sensitive OSCs for high performance OTFT based nitrogen dioxide(NO2)sensors,where the active OSC layer is based on ultraviolet-ozone(UVO)treated poly(3-hexylthiophene-2,5-diyl)(P3HT).Compared to conventional P3HT based OTFT sensors,the reported device exhibits a remarkable improvement of the gas response from 350%to 30000%.The studies in morphologies,chemical compositions and microstructures of the UVOtreated films reveal that a large number of carrier traps generated in the P3HT films is the decisive reason for the enhancement of sensing performance.Moreover,the optimized device shows great potential of practical applications on the stand points of sensitivity,selectivity,reusability and the ability of recovery,as well as limit of detection of~7.3 ppb.This simple method provides an innovative understanding for the role of the carrier traps in sensing performance and demonstrates a bright future for developing high performance OTFT gas sensors.展开更多
基金supported by the National Natural Science Foundations of China(21966002 and 21871047)the Natural Science Foundation of Jiangxi Province(20181ACB20003)+1 种基金the Training Program for Academic and Technical Leaders of Major Disciplines in Jiangxi Province(20194BCJ22010)the Graduate Innovation Project of East China University of Technology(DHYC-202023)。
文摘Direct separation of Xe and Kr from air or used nuclear fuel(UNF)off-gas by means of porous adsorbents is of industrial importance but is a very challenging task.In this work,we show a robust metal-organic framework(MOF),namely ECUT-60,which renders not only high chemical stability,but also unique structure with multiple traps.This leads to the ultrahigh Xe adsorption capacity,exceeding most reported porous materials.Impressively,this MOF also enables high selectivity of Xe over Kr,CO2,O2,and N2,leading to the high-performance separation for trace quantitites of Xe/Kr from a simulated UNF reprocessing off-gas.The separation capability has been demonstrated by using dynamic breakthrough experiments,giving the record Xe uptake up to 70.4 mmol/kg and the production of 19.7 mmol/kg pure Xe.Consequently,ECUT-60 has promising potential in direct production of Xe from UNF off-gas or air.The separation mechanism,as unveiled by theoretical calculation,is attributed to the multiple traps in ECUT-60 that affords rigid restrict for Xe atom via van der Waals force.
基金Project supported by the Ministry of Science and Technology of China(Grant No.2013YQ09094304)
文摘The loss rate of cold atoms in a trap due to residual gas collisions differs from that in a free state after the cold atoms are released from the trap. In this paper, the loss rate in a cold rubidium-87 atom cloud was measured in a magneto-optical trap （MOT） and during its free flight. The residual gas pressure was analyzed by a residual gas analyzer, and the pressure distribution in a vacuum chamber was numerically calculated by the angular coefficient method. The decay factor, which describes the decay behavior of cold atoms due to residual gas collisions during a free flight, was calculated. It was found that the decay factor agrees well with theoretical predictions under various vacuum conditions.
基金The National Petroleum Major Projects under contract Nos 2016ZX05026,2011ZX05025 and 2008ZX05025the National Natural Science Foundation Major Research Program of China under contract No.91528303+3 种基金the National Program on Key Basic Research Project of China(973 Program)under contract No.2009CB219400the Key Laboratory Project of Gansu Province under contract No.1309RTSA041the National Natural Science Foundation of China under contract No.41872172the SDUST Research Found under contract No.2018TDJH101
文摘By the end of 2019,more than 220 gas fields had been discovered in the South China Sea.In order to accurately determine the geological characteristics of the large-and medium-sized gas fields in the South China Sea,this study conducted a comprehensive examination of the gas fields.Based on the abundant available geologic and geochemical data,the distribution and key controlling factors of the hydrocarbon accumulation in the South China Sea were analyzed.The geological and geochemical features of the gas fields were as follows:(1)the gas fields were distributed similar to beads in the shape of a"C"along the northern,western,and southern continental margins;(2)the natural gas in the region was determined to be composed of higher amounts of alkane gas and less CO2;(3)the majority of the alkane gas was observed to be coal-type gas;(4)the gas reservoir types included structural reservoirs,lithologic reservoirs,and stratigraphic reservoirs,respectively;(5)the reservoir ages were mainly Oligocene,Miocene,and Pliocene,while the lithology was mainly organic reef,with some sandstone deposits;and(6)the main hydrocarbon accumulation period for the region was determined to be the late Pliocene-Quaternary Period.In addition,the main controlling factors of the gas reservoirs were confirmed to have been the development of coal measures,sufficient thermal evolution,and favorable migration and accumulation conditions.
基金supported by the National Natural Science Foundation of China(Grant Nos.61421002,61675041,51703019&31771079)the National Key R&D Program of China(Grant No.2018YFB0407102)+2 种基金the Project of Science and Technology of Sichuan Province(Grant Nos.2020YFG0281,2019YFG0121&2020YFG0279)City University of Hong Kong(Grant No.9610423)sponsored by Sichuan Province Key Laboratory of Display Science and Technology。
文摘Developing high sensitive organic semiconductors(OSCs)in organic thin-film transistors(OTFTs)is the key for OTFT based gas sensors.Herein,we report a simple processing route of highly sensitive OSCs for high performance OTFT based nitrogen dioxide(NO2)sensors,where the active OSC layer is based on ultraviolet-ozone(UVO)treated poly(3-hexylthiophene-2,5-diyl)(P3HT).Compared to conventional P3HT based OTFT sensors,the reported device exhibits a remarkable improvement of the gas response from 350%to 30000%.The studies in morphologies,chemical compositions and microstructures of the UVOtreated films reveal that a large number of carrier traps generated in the P3HT films is the decisive reason for the enhancement of sensing performance.Moreover,the optimized device shows great potential of practical applications on the stand points of sensitivity,selectivity,reusability and the ability of recovery,as well as limit of detection of~7.3 ppb.This simple method provides an innovative understanding for the role of the carrier traps in sensing performance and demonstrates a bright future for developing high performance OTFT gas sensors.
