Kr and Xe nuclide abundance and isotopic ratios of the uppermost layer of Fe-Mn Crusts from the western and central Pacific Ocean have been determined. The results indicate that the Kr and Xe isotopic composi-tions, l...Kr and Xe nuclide abundance and isotopic ratios of the uppermost layer of Fe-Mn Crusts from the western and central Pacific Ocean have been determined. The results indicate that the Kr and Xe isotopic composi-tions, like that of He, Ne and Ar, can be classified into two types： low3He/4He type and high3He/4He type. The low3He/4He type crusts have low84Kr and132Xe abundance, while the high3He/4He type crusts have high84Kr and132Xe abundance. The82Kr/84Kr ratios of the low3He/4He type crusts are lower than that of the air, while the83Kr/84Kr and86Kr/84Kr ratios are higher than those of the air. The Kr isotopic ratios of the high-er3He/4He type crusts are quite similar to those of the air. The128Xe/132Xe,130Xe/132Xe and131Xe/132Xe ratios of the low3He/4He type sample are distinctly lower than those of the air, whereas the129Xe/132Xe,134Xe/132Xe and136Xe/132Xe ratios are higher than those of the air. The low3He/4He type samples have the diagnostic characteristics of the MORB, with excess129, 131, 132, 134, 136Xe relative to130Xe compared with the solar wind. The128Xe/132Xe,130Xe/132Xe and131Xe/132Xe ratios of the high3He/4He type samples are slightly higher than those of the air, and the129Xe/132Xe,134Xe/132Xe and136Xe/132Xe ratios are qiute similar to those of the air. The noble gases in the Fe-Mn crusts are derived from the lower mantle, and they are a mixture of lower mantle primitive component, radiogenic component and subduction recycled component. The helium isotopic ra-tios of the low mantle reservoir are predominantly controlled by primitive He （3He） and U and Th radiogenic decayed He （4He）, but the isotopic ratios of the heavier noble gases, such as Ar, Kr and Xe, are controlled to different extent by recycling of subduction components. The difference of the noble isotopic compositions of the two type crusts is the result of the difference of the noble isotopic composition of the mantle source reservoir underneath the seamounts the crusts occurred, the noble gases of the high3He/4He type crusts are derived mainly from EM-type lower mantle reservoir, and the noble gases in the low3He/4He type crusts are derived mainly from HIMU-type lower mantle reservoir.展开更多
By considering the relative velocity distribution function and multipole expansion interaction Hamiltonian, a three-state model for calculating the cross section of laser-induced quadrupole-quadrupole collisional ener...By considering the relative velocity distribution function and multipole expansion interaction Hamiltonian, a three-state model for calculating the cross section of laser-induced quadrupole-quadrupole collisional energy transfer is presented. Calculated results in Xe-Kr system show that in the present system, the laser-induced collision process occurs for -4 ps, which is much shorter than the dipole-dipole laser-induced collisional energy transfer （LICET） process. The spectrum of laser-induced quadrupole quadrupole collisional energy transfer in Xe-Kr system has wider tunable range in an order of magnitude than the dipole-dipole LICET spectra. The peak cross section decreases and moves to the quasi-static wing with increasing temperature and the full width at half peak of the profile becomes larger as the system temperature increases.展开更多
As a rising star among porous solid materials,covalent organic frameworks(COFs)with excellent properties including but not limit to facilely controllable structure,high porosity,and multi-chemical functionality repres...As a rising star among porous solid materials,covalent organic frameworks(COFs)with excellent properties including but not limit to facilely controllable structure,high porosity,and multi-chemical functionality represent significant potential for efficient 127Xe/85Kr capture and separation.In this study,through tuning the length of the organic ligands,two-dimensional(2D)COF materials with identical connection group but different pore properties,denoted as ATFG-COF and TpPa-COF with AA-stacking model and TpBD-COF with AB-stacking model were synthesized and tested for Kr and Xe adsorption for the first time.Adsorption measurements indicate that the narrower pore apertures and higher porosity are conducive for COF materials to capture Xe and Kr.Furthermore,the Henry’s constant,isosteric heat of adsorption(Q_(st)),and ideal adsorbed solution theory(IAST)selectivity of ATFG-COF,the pore size of which is closest to the kinetic diameter of the Xe atom(0.41 nm)among 2D COF materials,were carried out based on the single component sorption isotherms.The results illustrate that the high isosteric heat values of Xe/Kr adsorption on ATFG-COF are 25 and 16 kJ/mol at room temperature,respectively.Henry’s law predicts that the selectivity factor of Xe to Kr is 6.07,consistent with the adsorption selectivity(ca.6)calculated based on the IAST.展开更多
基金The National Natural Science Foundation of China under contract No.40706028
文摘Kr and Xe nuclide abundance and isotopic ratios of the uppermost layer of Fe-Mn Crusts from the western and central Pacific Ocean have been determined. The results indicate that the Kr and Xe isotopic composi-tions, like that of He, Ne and Ar, can be classified into two types： low3He/4He type and high3He/4He type. The low3He/4He type crusts have low84Kr and132Xe abundance, while the high3He/4He type crusts have high84Kr and132Xe abundance. The82Kr/84Kr ratios of the low3He/4He type crusts are lower than that of the air, while the83Kr/84Kr and86Kr/84Kr ratios are higher than those of the air. The Kr isotopic ratios of the high-er3He/4He type crusts are quite similar to those of the air. The128Xe/132Xe,130Xe/132Xe and131Xe/132Xe ratios of the low3He/4He type sample are distinctly lower than those of the air, whereas the129Xe/132Xe,134Xe/132Xe and136Xe/132Xe ratios are higher than those of the air. The low3He/4He type samples have the diagnostic characteristics of the MORB, with excess129, 131, 132, 134, 136Xe relative to130Xe compared with the solar wind. The128Xe/132Xe,130Xe/132Xe and131Xe/132Xe ratios of the high3He/4He type samples are slightly higher than those of the air, and the129Xe/132Xe,134Xe/132Xe and136Xe/132Xe ratios are qiute similar to those of the air. The noble gases in the Fe-Mn crusts are derived from the lower mantle, and they are a mixture of lower mantle primitive component, radiogenic component and subduction recycled component. The helium isotopic ra-tios of the low mantle reservoir are predominantly controlled by primitive He （3He） and U and Th radiogenic decayed He （4He）, but the isotopic ratios of the heavier noble gases, such as Ar, Kr and Xe, are controlled to different extent by recycling of subduction components. The difference of the noble isotopic compositions of the two type crusts is the result of the difference of the noble isotopic composition of the mantle source reservoir underneath the seamounts the crusts occurred, the noble gases of the high3He/4He type crusts are derived mainly from EM-type lower mantle reservoir, and the noble gases in the low3He/4He type crusts are derived mainly from HIMU-type lower mantle reservoir.
文摘By considering the relative velocity distribution function and multipole expansion interaction Hamiltonian, a three-state model for calculating the cross section of laser-induced quadrupole-quadrupole collisional energy transfer is presented. Calculated results in Xe-Kr system show that in the present system, the laser-induced collision process occurs for -4 ps, which is much shorter than the dipole-dipole laser-induced collisional energy transfer （LICET） process. The spectrum of laser-induced quadrupole quadrupole collisional energy transfer in Xe-Kr system has wider tunable range in an order of magnitude than the dipole-dipole LICET spectra. The peak cross section decreases and moves to the quasi-static wing with increasing temperature and the full width at half peak of the profile becomes larger as the system temperature increases.
基金This work was supported by the National Natural Science Foundation of China(Nos.21906112,21790374).
文摘As a rising star among porous solid materials,covalent organic frameworks(COFs)with excellent properties including but not limit to facilely controllable structure,high porosity,and multi-chemical functionality represent significant potential for efficient 127Xe/85Kr capture and separation.In this study,through tuning the length of the organic ligands,two-dimensional(2D)COF materials with identical connection group but different pore properties,denoted as ATFG-COF and TpPa-COF with AA-stacking model and TpBD-COF with AB-stacking model were synthesized and tested for Kr and Xe adsorption for the first time.Adsorption measurements indicate that the narrower pore apertures and higher porosity are conducive for COF materials to capture Xe and Kr.Furthermore,the Henry’s constant,isosteric heat of adsorption(Q_(st)),and ideal adsorbed solution theory(IAST)selectivity of ATFG-COF,the pore size of which is closest to the kinetic diameter of the Xe atom(0.41 nm)among 2D COF materials,were carried out based on the single component sorption isotherms.The results illustrate that the high isosteric heat values of Xe/Kr adsorption on ATFG-COF are 25 and 16 kJ/mol at room temperature,respectively.Henry’s law predicts that the selectivity factor of Xe to Kr is 6.07,consistent with the adsorption selectivity(ca.6)calculated based on the IAST.
