Ion mobility spectrometry （IMS） is a very fast, highly sensitive, and inexpensive technique, it permits efficient monitoring of volatile organic compounds like alcohols. In this article, positive ion mobility spectr...Ion mobility spectrometry （IMS） is a very fast, highly sensitive, and inexpensive technique, it permits efficient monitoring of volatile organic compounds like alcohols. In this article, positive ion mobility spectra for six alcohol organic compounds have been systematically studied for the first time using a high-resolution IMS apparatus equipped with a discharge ionization source. Utilizing protonated water cluster ions （H2O）nH^＋ as the reactant ions and clean air as the drift gas, alcohol organic compounds, ethanol, 1- propanol, 2-propanol, 1-butanol, 1-pentanol and 2-octanol, all exhibit product ion characteristic peaks in their respective ion mobility spectrometry, that is a result of proton transfer reactions between the alcohols and reaction ions （H2O）nH^＋. The mixture of these alcohols, including two isomers, has been detected, and the results showed that they could be distinguished effectively in the ion mobility spectrum. The reduced mobility values have been determined, which are in very well agreement with the traditional ^63Ni-IMS experimental values. The exponential dilution method was used to calibrate the alcohol concentrations, and a detection limit available for the alcohols is in order of magnitude of a few ng/L.展开更多
Our recently studies on three types of reactions with hydrogen transfer as a key step,including catalytic asymmetric proton transfer reactions using"chiral proton transfer shuttle",catalytic B—H bond insert...Our recently studies on three types of reactions with hydrogen transfer as a key step,including catalytic asymmetric proton transfer reactions using"chiral proton transfer shuttle",catalytic B—H bond insertion containing a hydrogen atom transfer,and iron-catalyzed hydrosilylation reactions containing hydride transfer were briefly introduced.展开更多
This paper presents the results of experiments conducted to measure the cross-sections for elastic scattering and nucleon transfer channels in the ^(6)Li+^(9)Be reaction at an incident energy of 68 MeV:^(9)Be(^(6)Li,^...This paper presents the results of experiments conducted to measure the cross-sections for elastic scattering and nucleon transfer channels in the ^(6)Li+^(9)Be reaction at an incident energy of 68 MeV:^(9)Be(^(6)Li,^(6)Li)^(9)Be,^(9)Be(^(6)Li,7Li)8Be,^(9)Be(^(6)Li,7Li)^(8)Be_(2+),^(9)Be(^(6)Li,^(8)Li)^(7)Be,and ^(9)Be(^(6)Li,^(7)Be)^(8)Li.The objective of the study is to elucidate the manifestation of the cluster structure of ^(9)Be.Theoretical analysis of the contributions of the one-step and two-step neutron transfer mechanisms is performed using the distorted wave Born approximation method with the Fresco code.Good agreement between the calculations and the experimental data is obtained for the channels of elastic scattering ^(9)Be(^(6)Li,^(6)Li)^(9)Be,neutron ^(9)Be(^(6)Li,^(7)Li)^(8)Be,and proton transfer ^(9)Be(^(6)Li,^(7)Be)^(8)Li,as well as for the transfer of two neutrons ^(9)Be(^(6)Li,^(8)Li)^(7)Be.The dineutron cluster transfer mechanism makes a dominant contribution to the ^(9)Be(^(6)Li,^(8)Li)^(7)Be reaction channel at forward angles.展开更多
研制可快速、在线分析挥发性有机物(volatile organic compounds,VOCs)的质谱仪器是现代气态有机质谱的重要发展方向。本研究自行研制了小型高性能质子转移反应飞行时间质谱仪(proton transfer reaction time of flight mass spectromet...研制可快速、在线分析挥发性有机物(volatile organic compounds,VOCs)的质谱仪器是现代气态有机质谱的重要发展方向。本研究自行研制了小型高性能质子转移反应飞行时间质谱仪(proton transfer reaction time of flight mass spectrometry,PTR-TOF MS),仪器采用结构简单可靠的空心阴极放电源作为水蒸气电离源,以产生水合质子;线性漂移管作为分子离子反应管。该离子源产生的水合离子纯度高,为水合离子与VOCs的分子离子反应提供可控的反应条件。传输接口部分使用射频四极杆作为离子导向装置,以提高离子传输效率;配合小尺寸飞行时间质量分析器,兼顾仪器的灵敏度与分辨率。质子转移反应的测定原理使该仪器可以分析除少数烷烃外的绝大多数VOCs,同时分析过程不受空气组分的影响。分子离子峰为主的产物离子形式使谱图便于解析,适合高通量分析。测试结果表明,该仪器在m/z 115处全高半峰宽(full width half maximum,FWHM)分辨率优于2500,对丙酮、苯、甲苯的检出限在6×10^(-12)~9.6×10^(-11) mol/mol之间。将该仪器应用于人体呼吸气的成分分析,取得了良好的结果。展开更多
Volatile organic compounds(VOCs)are important precursors of secondary organic compounds and ozone,which raise major environmental concerns.To investigate the VOC emission characteristics,measurements of VOCs based on ...Volatile organic compounds(VOCs)are important precursors of secondary organic compounds and ozone,which raise major environmental concerns.To investigate the VOC emission characteristics,measurements of VOCs based on proton transfer reaction-mass spectrometry during 2017 were conducted in a coastal industrial area in Ningbo,Zhejiang Province,China.Based on seasonal variation in species concentration,the positive matrix factorization(PMF)receptor model was applied to apportion the sources of VOCs in each season.The PMF results revealed that unknown acetonitrile source,paint solvent,electronics industry,biomass burning,secondary formation and biogenic emission were mainly attributed to VOC pollution.Biomass burning and secondary formation were the major sources of VOCs and contributed more than 70%of VOC emissions in spring and autumn.Industry-related sources contributed 8.65%–31.2%of the VOCs throughout the year.The unknown acetonitrile source occurred in winter and spring,and contributed 7.6%–43.73%of the VOC emissions in the two seasons.Conditional probability function(CPF)analysis illustrated that the industry sources came from local emission,while biomass burning and biogenic emission mainly came from the northwest direction.The potential source contribution function(PSCF)model showed that secondary formation-related source was mainly from Jiangsu Province,northeastern China and the surrounding ocean.The potential source areas of unknown acetonitrile source were northern Zhejiang Province,southern Jiangsu Province and the northeastern coastal marine environments.展开更多
We present nuclear physics programs based on the planned experiments using rare isotope beams(RIBs) for the future Korean Rare Isotope Beams Accelerator facility(KRIA). This ambitious facility has both an Isotope Sepa...We present nuclear physics programs based on the planned experiments using rare isotope beams(RIBs) for the future Korean Rare Isotope Beams Accelerator facility(KRIA). This ambitious facility has both an Isotope Separation On Line(ISOL) and fragmentation capability for producing RIBs and accelerating beams of wide range mass of nuclides with energies of a few to hundreds Me V per nucleon. Low energy RIBs at Elab = 5 to 20 Me V per nucleon are for the study of nuclear structure and nuclear astrophysics toward and beyond the drip lines while higher energy RIBs produced by inflight fragmentation with the reaccelerated ions from the ISOL enable to explore the neutron drip lines in intermediate mass regions. The planned programs have goals for investigating internal structures of the exotic nuclei toward and beyond the nucleon drip lines by addressing the following issues: how the shell structure evolves in areas of extreme proton to neutron imbalance; whether the isospin symmetry maintains in isobaric mirror nuclei at and beyond the drip lines; how two-proton radioactivity affects abundances of the elements; what the role of the continuum states including resonant states above protondecay threshold in exotic nuclei is in astrophysical nuclear reaction processes, and how the nuclear reaction rates triggered by unbound proton-rich nuclei make an effect on rapid proton capture processes in a very hot stellar plasma.展开更多
The development of non‐precious metal catalysts that facilitate the oxygen evolution reaction(OER)is important for the widespread application of hydrogen production by water splitting.Various perovskite oxides have b...The development of non‐precious metal catalysts that facilitate the oxygen evolution reaction(OER)is important for the widespread application of hydrogen production by water splitting.Various perovskite oxides have been employed as active OER catalysts,however,the underlying mechanism that occurs at the catalyst‐electrolyte interface is still not well understood,prohibiting the design and preparation of advanced OER catalysts.Here,we report a systematic investigation into the effect of proton dynamics on the catalyst‐electrolyte interfaces of four perovskite catalysts:La_(0.5)Sr_(0.5)CoO_(3‐δ)(LSCO),LaCoO_(3),LaFeO_(3),and LaNiO_(3).The pH‐dependent OER activities,H/D kinetic isotope effect,and surface functionalization with phosphate anion groups were investigated to elucidate the role of proton dynamics in the rate‐limiting steps of the OER.For oxides with small charge‐transfer energies,such as LSCO and LaNiO_(3),non‐concerted proton‐coupled electron transfer steps are involved in the OER,and the activity is strongly controlled by the proton dynamics on the catalyst surface.The results demonstrate the important role of interfacial proton transfer in the OER mechanism,and suggest that proton dynamics at the interface should carefully be considered in the design of future high‐performance catalysts.展开更多
The additives-doped α-nickel hydroxides were prepared by supersonic co-precipitation method. The crystal structure and grain size of the prepared samples were characterized by X-ray diffraction （XRD） and Particle s...The additives-doped α-nickel hydroxides were prepared by supersonic co-precipitation method. The crystal structure and grain size of the prepared samples were characterized by X-ray diffraction （XRD） and Particle size distribution （PSD）, respectively. Cyclic voltammetry （CV） tests show that Al-Co-Y doped Ni（OH）2 has better reaction reversibility, higher proton diffusion coefficient than those of Al-Co doped Ni（OH）2. Al-Co-Y doped Ni（OH）2 also has lower charge-transfer resistance as shown by electrochemical impedance spectroscopy （EIS）. Charge/discharge tests show that the discharge capacity of Al-Co-Y doped Ni（OH）2 reaches 328 mAh/g at 0.2 C and 306 mAh/g at 0.5 C, while Al-Co doped Ni（OH）2 can only discharge a capacity of 308 mAh/g at 0.2 C and 267 mAh/g at 0.5 C.展开更多
基金Project supported by the National Natural Science Foundation of China(No.20577049)the Excellent Youth Foundation of Anhui Province Scientific Committee(No.06045098)the Hefei Institues of Physical Science,Chinese Academy of Sciences.
文摘Ion mobility spectrometry （IMS） is a very fast, highly sensitive, and inexpensive technique, it permits efficient monitoring of volatile organic compounds like alcohols. In this article, positive ion mobility spectra for six alcohol organic compounds have been systematically studied for the first time using a high-resolution IMS apparatus equipped with a discharge ionization source. Utilizing protonated water cluster ions （H2O）nH^＋ as the reactant ions and clean air as the drift gas, alcohol organic compounds, ethanol, 1- propanol, 2-propanol, 1-butanol, 1-pentanol and 2-octanol, all exhibit product ion characteristic peaks in their respective ion mobility spectrometry, that is a result of proton transfer reactions between the alcohols and reaction ions （H2O）nH^＋. The mixture of these alcohols, including two isomers, has been detected, and the results showed that they could be distinguished effectively in the ion mobility spectrum. The reduced mobility values have been determined, which are in very well agreement with the traditional ^63Ni-IMS experimental values. The exponential dilution method was used to calibrate the alcohol concentrations, and a detection limit available for the alcohols is in order of magnitude of a few ng/L.
基金We thank the National Natural Science Foundation of China(21625204,21971119)the"111"project(B06005)of the Ministry of Education of China+2 种基金the National Program for Support of Top-notch Young Professionalsthe Key-Area Research and Development Program of Guangdong Province(2020B010188001)Frontiers Science Center for New Organic Matter of Nankai University(63181206)for financial support.
文摘Our recently studies on three types of reactions with hydrogen transfer as a key step,including catalytic asymmetric proton transfer reactions using"chiral proton transfer shuttle",catalytic B—H bond insertion containing a hydrogen atom transfer,and iron-catalyzed hydrosilylation reactions containing hydride transfer were briefly introduced.
基金Supported by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (AP19677087)by the Russian Science Foundation (24-22-00117)。
文摘This paper presents the results of experiments conducted to measure the cross-sections for elastic scattering and nucleon transfer channels in the ^(6)Li+^(9)Be reaction at an incident energy of 68 MeV:^(9)Be(^(6)Li,^(6)Li)^(9)Be,^(9)Be(^(6)Li,7Li)8Be,^(9)Be(^(6)Li,7Li)^(8)Be_(2+),^(9)Be(^(6)Li,^(8)Li)^(7)Be,and ^(9)Be(^(6)Li,^(7)Be)^(8)Li.The objective of the study is to elucidate the manifestation of the cluster structure of ^(9)Be.Theoretical analysis of the contributions of the one-step and two-step neutron transfer mechanisms is performed using the distorted wave Born approximation method with the Fresco code.Good agreement between the calculations and the experimental data is obtained for the channels of elastic scattering ^(9)Be(^(6)Li,^(6)Li)^(9)Be,neutron ^(9)Be(^(6)Li,^(7)Li)^(8)Be,and proton transfer ^(9)Be(^(6)Li,^(7)Be)^(8)Li,as well as for the transfer of two neutrons ^(9)Be(^(6)Li,^(8)Li)^(7)Be.The dineutron cluster transfer mechanism makes a dominant contribution to the ^(9)Be(^(6)Li,^(8)Li)^(7)Be reaction channel at forward angles.
文摘研制可快速、在线分析挥发性有机物(volatile organic compounds,VOCs)的质谱仪器是现代气态有机质谱的重要发展方向。本研究自行研制了小型高性能质子转移反应飞行时间质谱仪(proton transfer reaction time of flight mass spectrometry,PTR-TOF MS),仪器采用结构简单可靠的空心阴极放电源作为水蒸气电离源,以产生水合质子;线性漂移管作为分子离子反应管。该离子源产生的水合离子纯度高,为水合离子与VOCs的分子离子反应提供可控的反应条件。传输接口部分使用射频四极杆作为离子导向装置,以提高离子传输效率;配合小尺寸飞行时间质量分析器,兼顾仪器的灵敏度与分辨率。质子转移反应的测定原理使该仪器可以分析除少数烷烃外的绝大多数VOCs,同时分析过程不受空气组分的影响。分子离子峰为主的产物离子形式使谱图便于解析,适合高通量分析。测试结果表明,该仪器在m/z 115处全高半峰宽(full width half maximum,FWHM)分辨率优于2500,对丙酮、苯、甲苯的检出限在6×10^(-12)~9.6×10^(-11) mol/mol之间。将该仪器应用于人体呼吸气的成分分析,取得了良好的结果。
基金supported by the Natural Science Foundation of China(52101279)the Natural Science Foundation of Hunan Provience(2020JJ5688)+3 种基金the Science Research Initiation Fund of Central South University(202045012)the Scientific Research Project of Education Department of Hunan Province(21B000)Jiangsu Key Laboratory for Carbon-Based Functional Materials&Devices,Soochow Universitythe Fundamental Research Funds for the Central Universities of Central South University(2020zzts753)。
基金supported by the National Nature Science Foundation for Young Scientists of China(Nos.41605094,41905115).
文摘Volatile organic compounds(VOCs)are important precursors of secondary organic compounds and ozone,which raise major environmental concerns.To investigate the VOC emission characteristics,measurements of VOCs based on proton transfer reaction-mass spectrometry during 2017 were conducted in a coastal industrial area in Ningbo,Zhejiang Province,China.Based on seasonal variation in species concentration,the positive matrix factorization(PMF)receptor model was applied to apportion the sources of VOCs in each season.The PMF results revealed that unknown acetonitrile source,paint solvent,electronics industry,biomass burning,secondary formation and biogenic emission were mainly attributed to VOC pollution.Biomass burning and secondary formation were the major sources of VOCs and contributed more than 70%of VOC emissions in spring and autumn.Industry-related sources contributed 8.65%–31.2%of the VOCs throughout the year.The unknown acetonitrile source occurred in winter and spring,and contributed 7.6%–43.73%of the VOC emissions in the two seasons.Conditional probability function(CPF)analysis illustrated that the industry sources came from local emission,while biomass burning and biogenic emission mainly came from the northwest direction.The potential source contribution function(PSCF)model showed that secondary formation-related source was mainly from Jiangsu Province,northeastern China and the surrounding ocean.The potential source areas of unknown acetonitrile source were northern Zhejiang Province,southern Jiangsu Province and the northeastern coastal marine environments.
文摘We present nuclear physics programs based on the planned experiments using rare isotope beams(RIBs) for the future Korean Rare Isotope Beams Accelerator facility(KRIA). This ambitious facility has both an Isotope Separation On Line(ISOL) and fragmentation capability for producing RIBs and accelerating beams of wide range mass of nuclides with energies of a few to hundreds Me V per nucleon. Low energy RIBs at Elab = 5 to 20 Me V per nucleon are for the study of nuclear structure and nuclear astrophysics toward and beyond the drip lines while higher energy RIBs produced by inflight fragmentation with the reaccelerated ions from the ISOL enable to explore the neutron drip lines in intermediate mass regions. The planned programs have goals for investigating internal structures of the exotic nuclei toward and beyond the nucleon drip lines by addressing the following issues: how the shell structure evolves in areas of extreme proton to neutron imbalance; whether the isospin symmetry maintains in isobaric mirror nuclei at and beyond the drip lines; how two-proton radioactivity affects abundances of the elements; what the role of the continuum states including resonant states above protondecay threshold in exotic nuclei is in astrophysical nuclear reaction processes, and how the nuclear reaction rates triggered by unbound proton-rich nuclei make an effect on rapid proton capture processes in a very hot stellar plasma.
文摘The development of non‐precious metal catalysts that facilitate the oxygen evolution reaction(OER)is important for the widespread application of hydrogen production by water splitting.Various perovskite oxides have been employed as active OER catalysts,however,the underlying mechanism that occurs at the catalyst‐electrolyte interface is still not well understood,prohibiting the design and preparation of advanced OER catalysts.Here,we report a systematic investigation into the effect of proton dynamics on the catalyst‐electrolyte interfaces of four perovskite catalysts:La_(0.5)Sr_(0.5)CoO_(3‐δ)(LSCO),LaCoO_(3),LaFeO_(3),and LaNiO_(3).The pH‐dependent OER activities,H/D kinetic isotope effect,and surface functionalization with phosphate anion groups were investigated to elucidate the role of proton dynamics in the rate‐limiting steps of the OER.For oxides with small charge‐transfer energies,such as LSCO and LaNiO_(3),non‐concerted proton‐coupled electron transfer steps are involved in the OER,and the activity is strongly controlled by the proton dynamics on the catalyst surface.The results demonstrate the important role of interfacial proton transfer in the OER mechanism,and suggest that proton dynamics at the interface should carefully be considered in the design of future high‐performance catalysts.
基金Funded by National Natural Science Foundation of China (No.10774030)Science and Technology Program of Guangzhou City of China (No.2008J1-C161)
文摘The additives-doped α-nickel hydroxides were prepared by supersonic co-precipitation method. The crystal structure and grain size of the prepared samples were characterized by X-ray diffraction （XRD） and Particle size distribution （PSD）, respectively. Cyclic voltammetry （CV） tests show that Al-Co-Y doped Ni（OH）2 has better reaction reversibility, higher proton diffusion coefficient than those of Al-Co doped Ni（OH）2. Al-Co-Y doped Ni（OH）2 also has lower charge-transfer resistance as shown by electrochemical impedance spectroscopy （EIS）. Charge/discharge tests show that the discharge capacity of Al-Co-Y doped Ni（OH）2 reaches 328 mAh/g at 0.2 C and 306 mAh/g at 0.5 C, while Al-Co doped Ni（OH）2 can only discharge a capacity of 308 mAh/g at 0.2 C and 267 mAh/g at 0.5 C.
