Objective To study the characterization apportionment of main ion concentrations of PM10 under the influence of trajectory wind direction in London. Methods PM10 samples from 1 May 1995 to 30 October 1995 of Oxford St...Objective To study the characterization apportionment of main ion concentrations of PM10 under the influence of trajectory wind direction in London. Methods PM10 samples from 1 May 1995 to 30 October 1995 of Oxford Street of Central London were collected, the metals and anions of which were measured using atomic absorption spectrometry （AAS） and ion chromatography （IC）. Composite trajectories representative of the air mass arriving in London at the same period were calculated based on basic routine back trajectories from the British Atmospheric Data Centre （BADC）. Results Concentration apportionments of main ions were similar when the trajectory was plotted back at 6 h, 12 h, and 24 h, some were obviously different. Mg, Ba, Pb, and Cu had similar peak apportionments at the area 180°-320°, but Zn and Ni at the area of 90°-270°, NO3^- and SO4^2- at the area of 100°-220°. Cl^- concentration peak apportionment was at the area of 220°-300°, which showed that Cl^- mainly came from the North Sea. Conclusion Trajectory wind direction has important effect on ion concentration apportionment of PM10 in London. The ions have similar concentration peak apportionments or their correlation coefficients are statistically significant.展开更多
A neutral beam injection (NBI) system has been developed and is being tested for an Experimental Advanced Superconducting Tokamak (EAST) device. The NBI system needs to be employed for an auxiliary heating and current...A neutral beam injection (NBI) system has been developed and is being tested for an Experimental Advanced Superconducting Tokamak (EAST) device. The NBI system needs to be employed for an auxiliary heating and current drive of EAST plasmas. The first long pulse ion source (LPIS-1) has been installed in the neutral beam test bed (NBTB) system, and the performance is being tested in the NBTB. The LPIS-1 consists of a magnetic bucket plasma generator with multipole cusp-fields and a set of tetrode accelerators with slit-type apertures (a transparency of 60%). The ion beam trajectories of the accelerator column are estimated for the LPIS-1, including an original structure, with the change of slit aperture distance, plasma grid shape, grid gap distance, and voltage ratio between a plasma grid and a gradient grid using the IGUN code. This kind of calculation for the ion beam trajectory may be useful for the estimation of beam extraction characteristics and the direction of accelerator upgrade or modification, prior to the experiments of ion beam extraction.展开更多
The following article has been retracted due to the investigation of complaints received against it. Mr. Mohammadali Ghorbani (corresponding author and also the last author) cheated the author’s name: Alireza Heidari...The following article has been retracted due to the investigation of complaints received against it. Mr. Mohammadali Ghorbani (corresponding author and also the last author) cheated the author’s name: Alireza Heidari. The scientific community takes a very strong view on this matter and we treat all unethical behavior such as plagiarism seriously. This paper published in Vol.3 No.3, 278-281, 2012, has been removed from this site.展开更多
High field asymmetric wave ion mobility spectrometry （FAIMS） is a powerful tool to detect and characterize gas-phase ions, while the unsolvable partial differential equation of ions moving in ion drift tube poses a ...High field asymmetric wave ion mobility spectrometry （FAIMS） is a powerful tool to detect and characterize gas-phase ions, while the unsolvable partial differential equation of ions moving in ion drift tube poses a big challenge to FAIMS spectral peak analysis. In this work, a universal and effective model of FAIMS spectral peak profile has been proposed by introducing ion trajectory and loss height. With this model, the influence of the structure of ion drift tube, dispersion voltages, compensation voltages, and carrier gas flow rate on the FAIMS spectral peak characteristics like peak shape, full width at half maximum and peak height is analyzed and discussed. The results show that the influence of different factors on the FAIMS spectral peak profile can be qualitatively described by the model which agrees with the experimental data.展开更多
In this paper,we introduce a method of quantitatively evaluating and controlling the space charge effect of a lasercooled three-dimensional（3 D） ion system in a linear Paul trap.The relationship among cooling effici...In this paper,we introduce a method of quantitatively evaluating and controlling the space charge effect of a lasercooled three-dimensional（3 D） ion system in a linear Paul trap.The relationship among cooling efficiency,ion quantity,and trapping strength is analyzed quantitatively,and the dynamic space distribution and temporal evolution of the 3 D ion system on a secular motion period time scale in the cooling process are obtained.The ion number influences the eigen-micromotion feature of the ion system.When trapping parameter q is ～ 0.3,relatively ideal cooling efficiency and equilibrium temperature can be obtained.The decrease of axial electrostatic potential is helpful in reducing the micromotion heating effect and the degradation in the total energy.Within a single secular motion period under different cooling conditions,ions transform from the cloud state（each ion disperses throughout the envelope of the ion system） to the liquid state（each ion is concentrated at a specific location in the ion system） and then to the crystal state（each ion is subjected to a fixed motion track）.These results are conducive to long-term storage and precise control,motion effect suppression,high-efficiency cooling,and increasing the precision of spectroscopy for a 3 D ion system.展开更多
为探究中国第十四届运动会(简称“十四运”)期间西安大气PM_(2.5)中水溶性无机离子浓度水平及来源,利用高分辨率MARGA ADI 2080离子在线分析仪对西安“十四运”前、“十四运”期间和“十四运”后水溶性无机离子进行实时观测,分析了不同...为探究中国第十四届运动会(简称“十四运”)期间西安大气PM_(2.5)中水溶性无机离子浓度水平及来源,利用高分辨率MARGA ADI 2080离子在线分析仪对西安“十四运”前、“十四运”期间和“十四运”后水溶性无机离子进行实时观测,分析了不同时段水溶性无机离子组分污染特征、pH变化及污染来源。结果表明,“十四运”前、“十四运”期间和“十四运”后PM_(2.5)质量浓度分别为13.4、11.9、32.6μg/m^(3),SNA(NO_(3)^(-)、SO_(4)^(2-)和NH_(4)^(+)三者统称)质量浓度分别为5.8、5.4、13.3μg/m^(3),占总水溶性无机离子的91.6%~93.6%。“十四运”前和“十四运”期间NO_(3)^(-)与SO_(4)^(2-)质量浓度比分别为0.7和0.9,表明移动源的比例增加,主要受交通管控的影响。“十四运”后NO_(3)^(-)与SO_(4)^(2-)质量浓度比为2.7,同时NO_(3)^(-)作为最丰富的离子,其质量浓度(7.4μg/m^(3))分别为“十四运”前(1.7μg/m^(3))和“十四运”期间(1.9μg/m^(3))的4.4和3.9倍。观测阶段,大气PM_(2.5)整体呈碱性,进一步通过热力学模型(ISORROPIA-II)计算得出酸性强度为“十四运”前>“十四运”期间>“十四运”后,这与大气富氨环境密切相关。使用主成分-多元线性回归模型(PCA-MLA)分析得到,二次源和扬尘源是观测期间PM_(2.5)主要的污染来源,“十四运”期间二次源的贡献降到最低。通过轨迹聚类及潜在源(PSCF)分析表明,PM_(2.5)污染主要为短距离污染传输,SNA潜在污染源区主要分布在西安市内以及周边地区。展开更多
基金This work was supported by China Scholarship Council.
文摘Objective To study the characterization apportionment of main ion concentrations of PM10 under the influence of trajectory wind direction in London. Methods PM10 samples from 1 May 1995 to 30 October 1995 of Oxford Street of Central London were collected, the metals and anions of which were measured using atomic absorption spectrometry （AAS） and ion chromatography （IC）. Composite trajectories representative of the air mass arriving in London at the same period were calculated based on basic routine back trajectories from the British Atmospheric Data Centre （BADC）. Results Concentration apportionments of main ions were similar when the trajectory was plotted back at 6 h, 12 h, and 24 h, some were obviously different. Mg, Ba, Pb, and Cu had similar peak apportionments at the area 180°-320°, but Zn and Ni at the area of 90°-270°, NO3^- and SO4^2- at the area of 100°-220°. Cl^- concentration peak apportionment was at the area of 220°-300°, which showed that Cl^- mainly came from the North Sea. Conclusion Trajectory wind direction has important effect on ion concentration apportionment of PM10 in London. The ions have similar concentration peak apportionments or their correlation coefficients are statistically significant.
文摘A neutral beam injection (NBI) system has been developed and is being tested for an Experimental Advanced Superconducting Tokamak (EAST) device. The NBI system needs to be employed for an auxiliary heating and current drive of EAST plasmas. The first long pulse ion source (LPIS-1) has been installed in the neutral beam test bed (NBTB) system, and the performance is being tested in the NBTB. The LPIS-1 consists of a magnetic bucket plasma generator with multipole cusp-fields and a set of tetrode accelerators with slit-type apertures (a transparency of 60%). The ion beam trajectories of the accelerator column are estimated for the LPIS-1, including an original structure, with the change of slit aperture distance, plasma grid shape, grid gap distance, and voltage ratio between a plasma grid and a gradient grid using the IGUN code. This kind of calculation for the ion beam trajectory may be useful for the estimation of beam extraction characteristics and the direction of accelerator upgrade or modification, prior to the experiments of ion beam extraction.
文摘The following article has been retracted due to the investigation of complaints received against it. Mr. Mohammadali Ghorbani (corresponding author and also the last author) cheated the author’s name: Alireza Heidari. The scientific community takes a very strong view on this matter and we treat all unethical behavior such as plagiarism seriously. This paper published in Vol.3 No.3, 278-281, 2012, has been removed from this site.
基金This work was supported by the National Natural Science Foundation of China （No.60871037 andNo.61004133） and the Innovation and Technology Fund of Hefei Institutes of Physical Science.
文摘High field asymmetric wave ion mobility spectrometry （FAIMS） is a powerful tool to detect and characterize gas-phase ions, while the unsolvable partial differential equation of ions moving in ion drift tube poses a big challenge to FAIMS spectral peak analysis. In this work, a universal and effective model of FAIMS spectral peak profile has been proposed by introducing ion trajectory and loss height. With this model, the influence of the structure of ion drift tube, dispersion voltages, compensation voltages, and carrier gas flow rate on the FAIMS spectral peak characteristics like peak shape, full width at half maximum and peak height is analyzed and discussed. The results show that the influence of different factors on the FAIMS spectral peak profile can be qualitatively described by the model which agrees with the experimental data.
基金Project supported by the National Key Research and Development Program of China(Grant No.2017YFA0304401)the National Natural Science Foundation of China(Grant Nos.11622434,11474318,91336211,and 11634013)+2 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB21030100)Hubei Province Science Fund for Distinguished Young Scholars(Grant No.2017CFA040)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.2015274)
文摘In this paper,we introduce a method of quantitatively evaluating and controlling the space charge effect of a lasercooled three-dimensional（3 D） ion system in a linear Paul trap.The relationship among cooling efficiency,ion quantity,and trapping strength is analyzed quantitatively,and the dynamic space distribution and temporal evolution of the 3 D ion system on a secular motion period time scale in the cooling process are obtained.The ion number influences the eigen-micromotion feature of the ion system.When trapping parameter q is ～ 0.3,relatively ideal cooling efficiency and equilibrium temperature can be obtained.The decrease of axial electrostatic potential is helpful in reducing the micromotion heating effect and the degradation in the total energy.Within a single secular motion period under different cooling conditions,ions transform from the cloud state（each ion disperses throughout the envelope of the ion system） to the liquid state（each ion is concentrated at a specific location in the ion system） and then to the crystal state（each ion is subjected to a fixed motion track）.These results are conducive to long-term storage and precise control,motion effect suppression,high-efficiency cooling,and increasing the precision of spectroscopy for a 3 D ion system.
文摘为探究中国第十四届运动会(简称“十四运”)期间西安大气PM_(2.5)中水溶性无机离子浓度水平及来源,利用高分辨率MARGA ADI 2080离子在线分析仪对西安“十四运”前、“十四运”期间和“十四运”后水溶性无机离子进行实时观测,分析了不同时段水溶性无机离子组分污染特征、pH变化及污染来源。结果表明,“十四运”前、“十四运”期间和“十四运”后PM_(2.5)质量浓度分别为13.4、11.9、32.6μg/m^(3),SNA(NO_(3)^(-)、SO_(4)^(2-)和NH_(4)^(+)三者统称)质量浓度分别为5.8、5.4、13.3μg/m^(3),占总水溶性无机离子的91.6%~93.6%。“十四运”前和“十四运”期间NO_(3)^(-)与SO_(4)^(2-)质量浓度比分别为0.7和0.9,表明移动源的比例增加,主要受交通管控的影响。“十四运”后NO_(3)^(-)与SO_(4)^(2-)质量浓度比为2.7,同时NO_(3)^(-)作为最丰富的离子,其质量浓度(7.4μg/m^(3))分别为“十四运”前(1.7μg/m^(3))和“十四运”期间(1.9μg/m^(3))的4.4和3.9倍。观测阶段,大气PM_(2.5)整体呈碱性,进一步通过热力学模型(ISORROPIA-II)计算得出酸性强度为“十四运”前>“十四运”期间>“十四运”后,这与大气富氨环境密切相关。使用主成分-多元线性回归模型(PCA-MLA)分析得到,二次源和扬尘源是观测期间PM_(2.5)主要的污染来源,“十四运”期间二次源的贡献降到最低。通过轨迹聚类及潜在源(PSCF)分析表明,PM_(2.5)污染主要为短距离污染传输,SNA潜在污染源区主要分布在西安市内以及周边地区。
