Numerical study was performed for a better understanding on thermomagnetic convection under magnetic quadrupole field utilizing the lattice Boltzmann method. Present problem was examined under non-gravitational and gr...Numerical study was performed for a better understanding on thermomagnetic convection under magnetic quadrupole field utilizing the lattice Boltzmann method. Present problem was examined under non-gravitational and gravitational conditions for a wide range of magnetic force number from 0 to 1000. Vertical walls of the square cavity were heated differentially while the horizontal walls were assumed to be adiabatic. Distributions of the flow and temperature field were clearly illustrated. Under non-gravitational condition, the flow presents a two-cellular structure with horizontal symmetry, and the average Nusselt number increases with the augment of magnetic force number. Under gravitational condition, two-cellular structure only occurs when the magnetic field is relatively strong, and the average Nusselt number decreases at first and then rises with the enhancing magnetic field. Results show that the magnetic field intensity and the Rayleigh number both have significant influence on convective heat transfer, and the gravity plays a positive role in heat transfer under weak magnetic field while a negative one for magnetic force numbers larger than 1×10~5.展开更多
Liquid chromatography coupled with the triple quadrupole mass spectrometry(LC-QQQ MS)technique is the most commonly used technique for quantitative analysis.It is widely used in pharmacology,targeted metabolomics,Chin...Liquid chromatography coupled with the triple quadrupole mass spectrometry(LC-QQQ MS)technique is the most commonly used technique for quantitative analysis.It is widely used in pharmacology,targeted metabolomics,Chinese medicine quality control,and other research fields.The technique monitors only characteristic precursors and product ions through multiple reaction monitoring(MRM)mode and can detect targeted molecules in complex matrix with high specificity and sensitivity.In the present study,a diarylamide derivative diuretic was used as an example to introduce the method establishment and parameter optimization of this liquid chromatography-mass spectrometry technique.Diuretic and its internal standard could be completely separated within a 5-min gradient,and the quantitative linear range was 1–1000 ng/mL with R2=0.9996 in practical samples.This study showed that the key to the method development for LC-QQQ MS was the selection of the LC mobile phase,the elution gradient,the declustering potential,and the collision energy of compounds in MS.展开更多
Electric quadrupole moments of low-lying excited states of Yb^+are calculated by relativistic coupled-cluster theory with perturbations from external fields.The field-dependent energy differentiation provides accurate...Electric quadrupole moments of low-lying excited states of Yb^+are calculated by relativistic coupled-cluster theory with perturbations from external fields.The field-dependent energy differentiation provides accurate values of the electric quadrupole moments of^2P3/2,^2D3/2,5/2,and^2F5/2,7/2 states which agree well with experimental values.The important role of the electronic correlation to the electric quadrupole moments is investigated.Our calculations indicate the early dispute of the electric quadrupole moment of the Yb^+(2F7/2)state for which the measured and theoretical values have a large discrepancy.These electric quadrupole moment values can help us to determine the electric quadrupole shifts in start-of-the-art experiments of the Yb+ion.展开更多
Highly charged nickel ions have been suggested as candidates for the ultra-precise optical clock, meanwhile the relevant experiment has been carried out. In the framework of the multiconfiguration Dirac–Hartree–Fock...Highly charged nickel ions have been suggested as candidates for the ultra-precise optical clock, meanwhile the relevant experiment has been carried out. In the framework of the multiconfiguration Dirac–Hartree–Fock(MCDHF)method, we calculated the hyperfine interaction constants, the Landég-factors, and the electric quadrupole moments for the low-lying states in the 61Ni11+,61Ni12+,61Ni14+, and61Ni15+ ions. These states are clock states of the selected clock transitions in highly charged nickel ions(see Fig. 1). Based on discussing the effects of the electron correlations, the Breit interaction, and quantum electrodynamics(QED) effect on these physical quantities, reasonable uncertainties were obtained for our calculated results. In addition, the electric quadrupole frequency shifts and the Zeeman frequency shifts of the clock transitions concerned were analyzed.展开更多
This paper presents a statement of the works performed in L.E.M.T.A by the members of the thermal and mechanical heterogeneous media research group during the last six years concerning the solving of coupled conductiv...This paper presents a statement of the works performed in L.E.M.T.A by the members of the thermal and mechanical heterogeneous media research group during the last six years concerning the solving of coupled conductive and radiative heat transfers within a multilayer and semi-transparent“wall”.Out of the authors,this paper allows to take inspiration from the works of D.Maillet,M.Lazard and V.Manias[19,20,21].The aim of these works is to represent in a macroscopic way,with the minimum number of thermophysical parameters,the heat transfers in a plane system composed of semi-transparent media.The approach we propose is semi-analytic(Kernel substitution technique,Laplace transformation)and allow to obtain in the Laplace domain an analytical solution that can be easily used.This method can be applied in two main scopes of applications:the estimation of thermophysical properties(phononic conductivity,optical thickness,Planck number for instance)of semi-transparent materials(glasses,crystals,glass wool,semi-conductors,synthetic diamonds,vitroceramics and so on)and the modelling of processes with semitransparent walls(for instance bottles forming,flat glass production,drying of paper).The method will be first presented and validated and two examples of applications will be then given.This method can be applied to semitransparent walls that emit,absorb and scatter the radiant energy(participating medium).It appears from the principle of a Kernel substitution technique applied to the radiative flux expression and initially introduced by Lick[1]that allows to change the character of the governing heat equation from the integro-differential form to a purely differential one.In the case of limiting cases of purely scattering and purely absorbing media,the solution of the radiative transfer equation is exact.In the general case,we make a two-flux approximation.In all cases,we assume a linear transfer and use the Laplace transform.The method can be applied to grey or grey by bands media,with isotropic or anisotropic scattering.The advantage of the method is fast computational times for good precision.展开更多
this study,the energy bands of quadrupole and octupole excited states are investigated.This is achieved by employing the Bohr Hamiltonian,incorporating quadrupole and octupole deformations whose variables are accurate...this study,the energy bands of quadrupole and octupole excited states are investigated.This is achieved by employing the Bohr Hamiltonian,incorporating quadrupole and octupole deformations whose variables are accurately separated.Subsequently,the Woods-Saxon potential is added to the problem.Because this problem cannot yield suitable solutions using conventional approximations,we solve it numerically using machine learning.A detailed description is given of how wave functions and their associated energies are obtained.Throughout this procedure,we demonstrate how machine learning aids us in easily accomplishing our objective.We examine and analyze the energy spectrum and possible multipole transitions for candidate isotopes^(226)Ra and^(226)Th.展开更多
建立了加速溶剂萃取(ASE),酸性硅胶柱、复合硅胶柱及碱性氧化铝柱纯化分离,气相色谱-三重四极杆质谱测定土壤中二英/呋喃(PCDD/Fs)、多氯联苯(PCBs)、多氯萘(PCNs)的分析方法。选用正己烷-二氯甲烷(50∶50,V/V)作为ASE的提取溶剂,设...建立了加速溶剂萃取(ASE),酸性硅胶柱、复合硅胶柱及碱性氧化铝柱纯化分离,气相色谱-三重四极杆质谱测定土壤中二英/呋喃(PCDD/Fs)、多氯联苯(PCBs)、多氯萘(PCNs)的分析方法。选用正己烷-二氯甲烷(50∶50,V/V)作为ASE的提取溶剂,设定提取温度为120℃,加标回收实验表明本方法可行。用100 m L正己烷-二氯甲烷(95∶5,V/V)及50 m L正己烷-二氯甲烷(50∶50,V/V)依次淋洗碱性氧化铝柱,得到组分A(PCBs及PCNs)与组分B(PCDD/Fs),实现了PCDD/Fs与另外两种化合物的分离,排除了同系物间及其它杂质的干扰。使用同位素稀释-气相色谱三重四极杆质谱法(GC-MS/MS),在选择反应监测(Selected reaction monitoring,SRM)模式下测定PCDD/Fs、PCBs和PCNs,3种化合物的仪器检出限(LOD)范围分别为0.04~0.25μg/L,0.10~0.20μg/L和0.01~0.05μg/L,目标物平均相对响应因子(RRF)的相对标准偏差(RSD)均小于13%。基质土加标实验中,3种化合物13C标记的同位素内标回收率的范围分别为50%~95%,51%~103%,49%~74%。实际样品的分析结果表明,PCDD/Fs、PCBs及PCNs在土壤样品中的总含量范围分别为16.1~1148 pg/g、6.6~152.6 pg/g及10.9~99.5 pg/g,且样品测定结果与高分辨质谱测定结果相吻合。展开更多
基金Project(11572056)supported by the National Natural Science Foundation of ChinaProject(15A006)supported by the Scientific Research Fund of Hunan Provincial Education Department,China
文摘Numerical study was performed for a better understanding on thermomagnetic convection under magnetic quadrupole field utilizing the lattice Boltzmann method. Present problem was examined under non-gravitational and gravitational conditions for a wide range of magnetic force number from 0 to 1000. Vertical walls of the square cavity were heated differentially while the horizontal walls were assumed to be adiabatic. Distributions of the flow and temperature field were clearly illustrated. Under non-gravitational condition, the flow presents a two-cellular structure with horizontal symmetry, and the average Nusselt number increases with the augment of magnetic force number. Under gravitational condition, two-cellular structure only occurs when the magnetic field is relatively strong, and the average Nusselt number decreases at first and then rises with the enhancing magnetic field. Results show that the magnetic field intensity and the Rayleigh number both have significant influence on convective heat transfer, and the gravity plays a positive role in heat transfer under weak magnetic field while a negative one for magnetic force numbers larger than 1×10~5.
基金National Natural Science Foundation of China(Grant No.22004004 and 81620108029).
文摘Liquid chromatography coupled with the triple quadrupole mass spectrometry(LC-QQQ MS)technique is the most commonly used technique for quantitative analysis.It is widely used in pharmacology,targeted metabolomics,Chinese medicine quality control,and other research fields.The technique monitors only characteristic precursors and product ions through multiple reaction monitoring(MRM)mode and can detect targeted molecules in complex matrix with high specificity and sensitivity.In the present study,a diarylamide derivative diuretic was used as an example to introduce the method establishment and parameter optimization of this liquid chromatography-mass spectrometry technique.Diuretic and its internal standard could be completely separated within a 5-min gradient,and the quantitative linear range was 1–1000 ng/mL with R2=0.9996 in practical samples.This study showed that the key to the method development for LC-QQQ MS was the selection of the LC mobile phase,the elution gradient,the declustering potential,and the collision energy of compounds in MS.
基金Project supported by the National Natural Science Foundation of China(Grant No.11874064)the Strategic Priority and the Research Program of the Chinese Academy of Sciences(Grant No.XDB21030300)+3 种基金the National Key Research and Development Program of China(Grant No.2016YFA0302104)Yong Liu acknowledges the Project of Hebei Educational Department,China(Grant No.ZD2018015)the Natural Science Foundation of Hebei Province,China(Grant No.A2019203507)Bing-Bing Suo acknowledges the financial support from the National Natural Science foundation of China(Grant Nos.21673174 and 21873077).
文摘Electric quadrupole moments of low-lying excited states of Yb^+are calculated by relativistic coupled-cluster theory with perturbations from external fields.The field-dependent energy differentiation provides accurate values of the electric quadrupole moments of^2P3/2,^2D3/2,5/2,and^2F5/2,7/2 states which agree well with experimental values.The important role of the electronic correlation to the electric quadrupole moments is investigated.Our calculations indicate the early dispute of the electric quadrupole moment of the Yb^+(2F7/2)state for which the measured and theoretical values have a large discrepancy.These electric quadrupole moment values can help us to determine the electric quadrupole shifts in start-of-the-art experiments of the Yb+ion.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11704398 and 11934014)the National Key Research and Development Program of China(Grant No.2017YFA0304402)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB21030300)。
文摘Highly charged nickel ions have been suggested as candidates for the ultra-precise optical clock, meanwhile the relevant experiment has been carried out. In the framework of the multiconfiguration Dirac–Hartree–Fock(MCDHF)method, we calculated the hyperfine interaction constants, the Landég-factors, and the electric quadrupole moments for the low-lying states in the 61Ni11+,61Ni12+,61Ni14+, and61Ni15+ ions. These states are clock states of the selected clock transitions in highly charged nickel ions(see Fig. 1). Based on discussing the effects of the electron correlations, the Breit interaction, and quantum electrodynamics(QED) effect on these physical quantities, reasonable uncertainties were obtained for our calculated results. In addition, the electric quadrupole frequency shifts and the Zeeman frequency shifts of the clock transitions concerned were analyzed.
文摘This paper presents a statement of the works performed in L.E.M.T.A by the members of the thermal and mechanical heterogeneous media research group during the last six years concerning the solving of coupled conductive and radiative heat transfers within a multilayer and semi-transparent“wall”.Out of the authors,this paper allows to take inspiration from the works of D.Maillet,M.Lazard and V.Manias[19,20,21].The aim of these works is to represent in a macroscopic way,with the minimum number of thermophysical parameters,the heat transfers in a plane system composed of semi-transparent media.The approach we propose is semi-analytic(Kernel substitution technique,Laplace transformation)and allow to obtain in the Laplace domain an analytical solution that can be easily used.This method can be applied in two main scopes of applications:the estimation of thermophysical properties(phononic conductivity,optical thickness,Planck number for instance)of semi-transparent materials(glasses,crystals,glass wool,semi-conductors,synthetic diamonds,vitroceramics and so on)and the modelling of processes with semitransparent walls(for instance bottles forming,flat glass production,drying of paper).The method will be first presented and validated and two examples of applications will be then given.This method can be applied to semitransparent walls that emit,absorb and scatter the radiant energy(participating medium).It appears from the principle of a Kernel substitution technique applied to the radiative flux expression and initially introduced by Lick[1]that allows to change the character of the governing heat equation from the integro-differential form to a purely differential one.In the case of limiting cases of purely scattering and purely absorbing media,the solution of the radiative transfer equation is exact.In the general case,we make a two-flux approximation.In all cases,we assume a linear transfer and use the Laplace transform.The method can be applied to grey or grey by bands media,with isotropic or anisotropic scattering.The advantage of the method is fast computational times for good precision.
基金Supported by the Natural Science Foundation of China(12275141)the Natural Science Foundation of Tianjin,China(20JCYBJC01510)。
文摘this study,the energy bands of quadrupole and octupole excited states are investigated.This is achieved by employing the Bohr Hamiltonian,incorporating quadrupole and octupole deformations whose variables are accurately separated.Subsequently,the Woods-Saxon potential is added to the problem.Because this problem cannot yield suitable solutions using conventional approximations,we solve it numerically using machine learning.A detailed description is given of how wave functions and their associated energies are obtained.Throughout this procedure,we demonstrate how machine learning aids us in easily accomplishing our objective.We examine and analyze the energy spectrum and possible multipole transitions for candidate isotopes^(226)Ra and^(226)Th.
文摘建立了加速溶剂萃取(ASE),酸性硅胶柱、复合硅胶柱及碱性氧化铝柱纯化分离,气相色谱-三重四极杆质谱测定土壤中二英/呋喃(PCDD/Fs)、多氯联苯(PCBs)、多氯萘(PCNs)的分析方法。选用正己烷-二氯甲烷(50∶50,V/V)作为ASE的提取溶剂,设定提取温度为120℃,加标回收实验表明本方法可行。用100 m L正己烷-二氯甲烷(95∶5,V/V)及50 m L正己烷-二氯甲烷(50∶50,V/V)依次淋洗碱性氧化铝柱,得到组分A(PCBs及PCNs)与组分B(PCDD/Fs),实现了PCDD/Fs与另外两种化合物的分离,排除了同系物间及其它杂质的干扰。使用同位素稀释-气相色谱三重四极杆质谱法(GC-MS/MS),在选择反应监测(Selected reaction monitoring,SRM)模式下测定PCDD/Fs、PCBs和PCNs,3种化合物的仪器检出限(LOD)范围分别为0.04~0.25μg/L,0.10~0.20μg/L和0.01~0.05μg/L,目标物平均相对响应因子(RRF)的相对标准偏差(RSD)均小于13%。基质土加标实验中,3种化合物13C标记的同位素内标回收率的范围分别为50%~95%,51%~103%,49%~74%。实际样品的分析结果表明,PCDD/Fs、PCBs及PCNs在土壤样品中的总含量范围分别为16.1~1148 pg/g、6.6~152.6 pg/g及10.9~99.5 pg/g,且样品测定结果与高分辨质谱测定结果相吻合。
