High purity magnesium is not only an important basic raw material for semiconductor and electronics industries,but also a promising new generation of electrochemical energy storage materials and biomedical materials.I...High purity magnesium is not only an important basic raw material for semiconductor and electronics industries,but also a promising new generation of electrochemical energy storage materials and biomedical materials.Impurities in high-purity magnesium affect material properties,which has become the most critical factor restricting its application.However,accurate analysis of multiple ultra-trace impurity elements in high-purity magnesium is extremely challenging.In this paper,based on the synergistic effect of N_(2)O/H_(2) reaction gas mixture to eliminate spectral interference of inductively coupled plasma tandem mass spectrometry(ICP-MS/MS),a new strategy for the quantification of 45 ultra-trace impurity elements in high-purity magnesium was proposed.The results indicated that the limits of detection(LOD)were in the range of 0.02–18.5 ng L^(−1);the LODs of the challenging non-metallic elements Si and S were 18.5 and 12.2 ng L^(−1),respectively;and the LODs of all the other analytes were less than 10 ng L^(−1).Even under hot plasma conditions,LODs of alkali metal elements were also less than 5 ng L^(−1).The spike recovery of each analyte was 93.6%–107%,and the relative standard deviation(RSD)was 3.2%–6.9%,respectively.At a 95%level of confidence,no significant differences were found between the results obtained under the optimal conditions for the analyte with the developed method and the measurement results of SF-ICP-MS.The developed method indicated low LOD,high sample throughput,and complete interference elimination,demonstrating a new avenue for the rapid determination of ultra-trace elements in high-purity magnesium.展开更多
The photodissociationdynamicsof small(H_(2)O)_(n)^(+)(n=2-5)clusters have been studied at 308 nm using a high resolution cryogenic cylindrical ion trap velocity map imaging spectrometer.Time-of-flight mass spectra and...The photodissociationdynamicsof small(H_(2)O)_(n)^(+)(n=2-5)clusters have been studied at 308 nm using a high resolution cryogenic cylindrical ion trap velocity map imaging spectrometer.Time-of-flight mass spectra and images of ionic photofragments are recorded.(H_(2)O)_(2)^(+)clusters dissociate to yield H_(3)O^(+)and H_(2)O^(+)photofragments,indicating the presence of both proton-transferred(H_(3)O^(+)-OH)and hemibonded(H_(2)O-OH_(2))^(+)structures for the dimer cluster.(H_(2)O)_(n)^(+)(n=3-5)clusters prevailingly dissociate to the H+(H_(2)O)_(n-2,...1)photofragments by losing both of OH and H_(2)O components,and the(H_(2)O)_(5)^(+)cluster shows an additional channel to produce H^(+)(H_(2)O)_(4)by only losing OH.The former suggests the(H_(2)O)_(n-2)H_(3)_(O)^(+)OH structures for the(H_(2)O)_(n)^(+)(n=3-5)clusters,while the latter suggests in(H_(2)O)_(5)^(+)that,the H_(3)O^(+)core and OH are separated by H_(2)O.The results elucidate the structure progresses of small(H_(2)O)_(n)^(+)clusters.The experimental images yield negative and small values for the anisotropy parameters of photofragments,indicating that(H_(2)O)_(n)^(+)(n=2-5)clusters undergo vertical electronic transitions upon photon absorption followed by slow dissociation,and lead to highly internally excited photofragments.展开更多
Geomagnetic storm events have a strong influence on the ionosphere–thermosphere(I-T)coupling system.Analyzing the regional response process of the I-T system and its differences across the northern and southern hemis...Geomagnetic storm events have a strong influence on the ionosphere–thermosphere(I-T)coupling system.Analyzing the regional response process of the I-T system and its differences across the northern and southern hemispheres is an important but challenging task.In this study,we used a combination of multiple observations and a model simulation to examine the north–south hemispheric difference in the I-T coupling system in the American and Asian sectors during the geomagnetic superstorm that occurred in May 2024.Observations of the total electron content(TEC)showed that the Asian sector had negative storms in the northern hemisphere and positive storms in the southern hemisphere,a process that exacerbated the hemispheric differences in the TEC.However,both hemispheres of the American sector showed negative storms.The thermospheric composition changes also differed between the two sectors,and their variation could partially explain the hemispheric differences caused by positive and negative storms.Moreover,the influence of the thermospheric density change was less than that of the thermospheric composition.Finally,the dynamic effect of the thermospheric wind and the plasma transport processes strongly modulated the north–south differences in the TEC at nighttime in the American and Asian sectors,respectively,during this superstorm.展开更多
The development of aqueous zinc-ion batteries (AZIBs) marks a significant advancement in the field of sustainable and environmentally friendly energy storage.To address the challenges faced by singlephase vanadium-bas...The development of aqueous zinc-ion batteries (AZIBs) marks a significant advancement in the field of sustainable and environmentally friendly energy storage.To address the challenges faced by singlephase vanadium-based oxides,such as poor conductivity and dissolution in electrolytes,this study introduces vacuum S/N doping to fabricate V_(2)O_(3)/VO_(2)@S/N-C nanofibers,improving the cycling stability and enhancing the capacity.The V_(2)O_(3)/VO_(2)@S/N-C electrode exhibits exceptional cyclic stability,retaining a capacity of 133.3 m A h g^(-1)after 30,000 cycles at a high current density of 100 A g^(-1)and a capacity retention of 81.8%after 150,000 cycles at 200 A g^(-1).Characterizations using ex-situ X-ray diffraction and ex-situ X-ray photoelectron spectroscopy reveal co-intercalation of H^(+)and Zn^(2+)in the V_(2)O_(3)/VO_(2)@S/N-C electrode.Due to the presence of S_(2)^(2-),more phases changed to V_(10)O_(24).12H_(2)O,making the V_(2)O_(3)/VO_(2)@S/N-C electrode better reversible.By elucidating the zinc storage mechanism and demonstrating the stable performance of the doped electrode,this work contributes valuable insights into the optimization of the electrode materials for future energy storage solutions.展开更多
基金supported by the Natural Science Foundation of China(52171103 and 21975289).
文摘High purity magnesium is not only an important basic raw material for semiconductor and electronics industries,but also a promising new generation of electrochemical energy storage materials and biomedical materials.Impurities in high-purity magnesium affect material properties,which has become the most critical factor restricting its application.However,accurate analysis of multiple ultra-trace impurity elements in high-purity magnesium is extremely challenging.In this paper,based on the synergistic effect of N_(2)O/H_(2) reaction gas mixture to eliminate spectral interference of inductively coupled plasma tandem mass spectrometry(ICP-MS/MS),a new strategy for the quantification of 45 ultra-trace impurity elements in high-purity magnesium was proposed.The results indicated that the limits of detection(LOD)were in the range of 0.02–18.5 ng L^(−1);the LODs of the challenging non-metallic elements Si and S were 18.5 and 12.2 ng L^(−1),respectively;and the LODs of all the other analytes were less than 10 ng L^(−1).Even under hot plasma conditions,LODs of alkali metal elements were also less than 5 ng L^(−1).The spike recovery of each analyte was 93.6%–107%,and the relative standard deviation(RSD)was 3.2%–6.9%,respectively.At a 95%level of confidence,no significant differences were found between the results obtained under the optimal conditions for the analyte with the developed method and the measurement results of SF-ICP-MS.The developed method indicated low LOD,high sample throughput,and complete interference elimination,demonstrating a new avenue for the rapid determination of ultra-trace elements in high-purity magnesium.
基金This work is supported by the National Natural Science Foundation of China(No.22103075,No.21827804,and No.22173089)the National Key R&D Program of China(No.2021YFA0716801and No.2017YFA0303502).
文摘The photodissociationdynamicsof small(H_(2)O)_(n)^(+)(n=2-5)clusters have been studied at 308 nm using a high resolution cryogenic cylindrical ion trap velocity map imaging spectrometer.Time-of-flight mass spectra and images of ionic photofragments are recorded.(H_(2)O)_(2)^(+)clusters dissociate to yield H_(3)O^(+)and H_(2)O^(+)photofragments,indicating the presence of both proton-transferred(H_(3)O^(+)-OH)and hemibonded(H_(2)O-OH_(2))^(+)structures for the dimer cluster.(H_(2)O)_(n)^(+)(n=3-5)clusters prevailingly dissociate to the H+(H_(2)O)_(n-2,...1)photofragments by losing both of OH and H_(2)O components,and the(H_(2)O)_(5)^(+)cluster shows an additional channel to produce H^(+)(H_(2)O)_(4)by only losing OH.The former suggests the(H_(2)O)_(n-2)H_(3)_(O)^(+)OH structures for the(H_(2)O)_(n)^(+)(n=3-5)clusters,while the latter suggests in(H_(2)O)_(5)^(+)that,the H_(3)O^(+)core and OH are separated by H_(2)O.The results elucidate the structure progresses of small(H_(2)O)_(n)^(+)clusters.The experimental images yield negative and small values for the anisotropy parameters of photofragments,indicating that(H_(2)O)_(n)^(+)(n=2-5)clusters undergo vertical electronic transitions upon photon absorption followed by slow dissociation,and lead to highly internally excited photofragments.
基金supported by the National Natural Science Foundation of China (Grant Nos. 42030202, 42241115, and 42174204)the China Postdoctoral Science Foundation (Grant No. 2023M743467)+2 种基金the Youth Innovation Promotion Association of the Chinese Academy of Sciences (Grant No. Y202021)the National Key R&D Program of China (Grant No. 2022YFF0504400)the Opening Funding of the Chinese Academy of Sciences dedicated to the Chinese Meridian Project
文摘Geomagnetic storm events have a strong influence on the ionosphere–thermosphere(I-T)coupling system.Analyzing the regional response process of the I-T system and its differences across the northern and southern hemispheres is an important but challenging task.In this study,we used a combination of multiple observations and a model simulation to examine the north–south hemispheric difference in the I-T coupling system in the American and Asian sectors during the geomagnetic superstorm that occurred in May 2024.Observations of the total electron content(TEC)showed that the Asian sector had negative storms in the northern hemisphere and positive storms in the southern hemisphere,a process that exacerbated the hemispheric differences in the TEC.However,both hemispheres of the American sector showed negative storms.The thermospheric composition changes also differed between the two sectors,and their variation could partially explain the hemispheric differences caused by positive and negative storms.Moreover,the influence of the thermospheric density change was less than that of the thermospheric composition.Finally,the dynamic effect of the thermospheric wind and the plasma transport processes strongly modulated the north–south differences in the TEC at nighttime in the American and Asian sectors,respectively,during this superstorm.
基金financially supported by the Natural Science Foundation of China (Grant No. 52272063)the Jiangxi Provincial Natural Science Foundation (No. 20224BAB214037, 20232BAB204022, 20232BAB204019)。
文摘The development of aqueous zinc-ion batteries (AZIBs) marks a significant advancement in the field of sustainable and environmentally friendly energy storage.To address the challenges faced by singlephase vanadium-based oxides,such as poor conductivity and dissolution in electrolytes,this study introduces vacuum S/N doping to fabricate V_(2)O_(3)/VO_(2)@S/N-C nanofibers,improving the cycling stability and enhancing the capacity.The V_(2)O_(3)/VO_(2)@S/N-C electrode exhibits exceptional cyclic stability,retaining a capacity of 133.3 m A h g^(-1)after 30,000 cycles at a high current density of 100 A g^(-1)and a capacity retention of 81.8%after 150,000 cycles at 200 A g^(-1).Characterizations using ex-situ X-ray diffraction and ex-situ X-ray photoelectron spectroscopy reveal co-intercalation of H^(+)and Zn^(2+)in the V_(2)O_(3)/VO_(2)@S/N-C electrode.Due to the presence of S_(2)^(2-),more phases changed to V_(10)O_(24).12H_(2)O,making the V_(2)O_(3)/VO_(2)@S/N-C electrode better reversible.By elucidating the zinc storage mechanism and demonstrating the stable performance of the doped electrode,this work contributes valuable insights into the optimization of the electrode materials for future energy storage solutions.
