Aluminum is concerned as a possible cause of many diseases.To investigate the long-term A1 biokinetics and bioavailability in various kinds of Al-contained medicine and food,an accelerator mass spectrometry(AMS)based ...Aluminum is concerned as a possible cause of many diseases.To investigate the long-term A1 biokinetics and bioavailability in various kinds of Al-contained medicine and food,an accelerator mass spectrometry(AMS)based on the HI-13 tandem has been established for biological analysis with ^(26)A1(T_(1/2) = 716,000 years) as the tracer.In this paper,the animal tracing,sample preparation procedure and ^(26)A1-AMS measurement are presented.The sample preparation procedure has been simplified.A high sensitivity of 5×10^(-15) for ^(26)A1/^(27)A1 has been achieved.Two phases were found before and after a break time(t_b)for the ^(26)A1 retained in blood and brain,with t_b≈8 and12 h after the ^(26)Al tracer injection,respectively.展开更多
Aluminum is the primary structural material in nuclear engineering,and its cross section induced by 14-MeV neutrons is of great significance.To address the issue of insufficient accuracy for the^(27)Al(n,2n)^(26)Al re...Aluminum is the primary structural material in nuclear engineering,and its cross section induced by 14-MeV neutrons is of great significance.To address the issue of insufficient accuracy for the^(27)Al(n,2n)^(26)Al reaction cross section,the activation method and accelerator mass spectrometry(AMS)technique were used to determine the^(27)Al(n,2n)^(26)Al cross section,which could be used as a D-T plasma ion temperature monitor in fusion reactors.At the China Academy of Engineering Physics,neutron activation was performed using a K-400 neutron generator produced by the T(d,n)4He reaction.The^(26)Al∕^(27)Al isotope ratios were measured using the newly installed GYIG 1 MV AMS at the Institute of Geochemistry,Chinese Academy of Sciences.The neutron flux was monitored by measuring the activity of 92mNb produced by the 93Nb(n,2n)92mNb reaction.The measured results were compared with available data in the experimental nuclear reaction database,and the measured values showed a reasonable degree of consistency with partially available literature data.The newly acquired cross-sectional data at 12 neutron energy points through systematic measurements clarified the divergence,which has two different growth trends from the existing experimental values.The obtained results are also compared with the corresponding evaluated database,and the newly calculated excitation functions with TALYS−1.95 and EMPIRE−3.2 codes,the agreement with CENDL−3.2,TENDL-2021 and EMPIRE−3.2 results are generally acceptable.A substantial improvement in the knowledge of the^(27)Al(n,2n)^(26)Al reaction excitation function was obtained in the present work,which will lay the foundation for the diagnosis of the fusion ion temperature,testing of the nuclear physics model,evaluation of nuclear data,etc.展开更多
Cosmogenic nuclide exposure dating is one of the most intensively applied dating methods with which to study glacial geomorphology.Glacial erratics have been the major dating objective in many studies.Some research ha...Cosmogenic nuclide exposure dating is one of the most intensively applied dating methods with which to study glacial geomorphology.Glacial erratics have been the major dating objective in many studies.Some research has proposed that glacial erratics may undergo rollover and re-transportation during the late exposure stage,which can affect the dating results.However,there is no direct evidence to confirm this possibility.In this study,we collected seven samples from a vertical section inside a glacial erratic in the paleo-Daocheng ice cap in the southeastern Tibetan Plateau,measuring their contents of the cosmogenic nuclides ^(10)Be and ^(26)Al.The results show that from the top to the bottom,the concentrations of 10Be were(1.21±0.05)×10^(6),(1.00±0.02)×10^(6),(0.88±0.03)×10^(6),(0.77±0.02)×10^(6),(0.75±0.03)×10^(6),(0.95±0.03)×10^(6) and(1.46±0.04)×10^(6) atoms/g.The ^(10)Be concentrations decreased from(1.21±0.05)×10^(6) atoms/g to(0.75±0.03)×10^(6) atoms/g and then increased to(1.46±0.04)×10^(6) atoms/g,which is not consistent with the theoretical prediction of a gradual decrease.This phenomenon indicates that the glacial erratic may have rolled over at least once.The lower surface of the erratic could have been on top at some time in the past.Therefore,its exposure age was greater than the exposure age that was expected,based on its current orientation.This study provides numerical evidence for an erratic rollover event.展开更多
基金supported by National Natural Science Foundation of China(No.41166002)Guangxi Natural Science Foundation(Nos.2012GXNSFBA053004,2013GXNSFFA019001)Guangxi New Century Education Project(No.2013JGZ100)
文摘Aluminum is concerned as a possible cause of many diseases.To investigate the long-term A1 biokinetics and bioavailability in various kinds of Al-contained medicine and food,an accelerator mass spectrometry(AMS)based on the HI-13 tandem has been established for biological analysis with ^(26)A1(T_(1/2) = 716,000 years) as the tracer.In this paper,the animal tracing,sample preparation procedure and ^(26)A1-AMS measurement are presented.The sample preparation procedure has been simplified.A high sensitivity of 5×10^(-15) for ^(26)A1/^(27)A1 has been achieved.Two phases were found before and after a break time(t_b)for the ^(26)A1 retained in blood and brain,with t_b≈8 and12 h after the ^(26)Al tracer injection,respectively.
基金the Open Project of Guangxi Key Laboratory of Nuclear Physics and Nuclear Technology(NLK 2022-04)the Central Government Guidance Funds for Local Scientific and Technological Development,China(No.Guike,ZY22096024)+1 种基金the National Natural Science Foundation of China(12065003)Guangxi Key R&D Project(2023AB07029).
文摘Aluminum is the primary structural material in nuclear engineering,and its cross section induced by 14-MeV neutrons is of great significance.To address the issue of insufficient accuracy for the^(27)Al(n,2n)^(26)Al reaction cross section,the activation method and accelerator mass spectrometry(AMS)technique were used to determine the^(27)Al(n,2n)^(26)Al cross section,which could be used as a D-T plasma ion temperature monitor in fusion reactors.At the China Academy of Engineering Physics,neutron activation was performed using a K-400 neutron generator produced by the T(d,n)4He reaction.The^(26)Al∕^(27)Al isotope ratios were measured using the newly installed GYIG 1 MV AMS at the Institute of Geochemistry,Chinese Academy of Sciences.The neutron flux was monitored by measuring the activity of 92mNb produced by the 93Nb(n,2n)92mNb reaction.The measured results were compared with available data in the experimental nuclear reaction database,and the measured values showed a reasonable degree of consistency with partially available literature data.The newly acquired cross-sectional data at 12 neutron energy points through systematic measurements clarified the divergence,which has two different growth trends from the existing experimental values.The obtained results are also compared with the corresponding evaluated database,and the newly calculated excitation functions with TALYS−1.95 and EMPIRE−3.2 codes,the agreement with CENDL−3.2,TENDL-2021 and EMPIRE−3.2 results are generally acceptable.A substantial improvement in the knowledge of the^(27)Al(n,2n)^(26)Al reaction excitation function was obtained in the present work,which will lay the foundation for the diagnosis of the fusion ion temperature,testing of the nuclear physics model,evaluation of nuclear data,etc.
基金supported by the National Natural Science Foundation of China(Grant nos.41971009 and 41503054)the CASKJZD-EW-G03-04 project(Grant No.Y4422101001)+1 种基金the General Financial Grant of the China Postdoctoral Science Foundation(Grant No.2015M582728)the Priority AcademicProgram Development of Jiangsu Higher EducationInstitutions(Grant No.164320H116)。
文摘Cosmogenic nuclide exposure dating is one of the most intensively applied dating methods with which to study glacial geomorphology.Glacial erratics have been the major dating objective in many studies.Some research has proposed that glacial erratics may undergo rollover and re-transportation during the late exposure stage,which can affect the dating results.However,there is no direct evidence to confirm this possibility.In this study,we collected seven samples from a vertical section inside a glacial erratic in the paleo-Daocheng ice cap in the southeastern Tibetan Plateau,measuring their contents of the cosmogenic nuclides ^(10)Be and ^(26)Al.The results show that from the top to the bottom,the concentrations of 10Be were(1.21±0.05)×10^(6),(1.00±0.02)×10^(6),(0.88±0.03)×10^(6),(0.77±0.02)×10^(6),(0.75±0.03)×10^(6),(0.95±0.03)×10^(6) and(1.46±0.04)×10^(6) atoms/g.The ^(10)Be concentrations decreased from(1.21±0.05)×10^(6) atoms/g to(0.75±0.03)×10^(6) atoms/g and then increased to(1.46±0.04)×10^(6) atoms/g,which is not consistent with the theoretical prediction of a gradual decrease.This phenomenon indicates that the glacial erratic may have rolled over at least once.The lower surface of the erratic could have been on top at some time in the past.Therefore,its exposure age was greater than the exposure age that was expected,based on its current orientation.This study provides numerical evidence for an erratic rollover event.
