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
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
建立一种基于美国官方分析化学师协会(Association of Official Analytical Chemists,AOAC)方法检测黑果枸杞及其制品中花青素含量的改进pH示差法。考察了黑果枸杞及其制品中花青素的最佳提取和检测条件,通过液相色谱-三重四级杆串联质...建立一种基于美国官方分析化学师协会(Association of Official Analytical Chemists,AOAC)方法检测黑果枸杞及其制品中花青素含量的改进pH示差法。考察了黑果枸杞及其制品中花青素的最佳提取和检测条件,通过液相色谱-三重四级杆串联质谱法鉴别出黑果枸杞中花青素的具体化学结构,并计算出混合花青素的平均摩尔质量。通过分光光度法测得混合花青素的平均摩尔消光系数,对改进后的pH示差法进行方法学验证和花青素的含量测定。结果显示,最佳提取和检测条件如下:黑果枸杞花青素提取溶剂为盐酸-80%(体积分数)乙醇(3∶97,体积比),料液比为1∶100(g∶mL),提取温度为50℃,提取时间为30 min,缓冲溶液稀释5倍后静置平衡20 min。液相色谱-三重四级杆串联质谱法鉴别黑果枸杞中主要以矮牵牛素类花青素为主(占97.96%),黑果枸杞特有的混合花青素平均摩尔质量为912.7 g/mol,平均摩尔消光系数为29591 L/(mol·cm)。pH示差法改进后能够满足方法学验证要求,固体样品和液体样品最低检出限分别为28.2 mg/100 g、0.282 mg/100 mL。方法改进后花青素提取增长率均大于20%,静置平衡20 min后单次检测结果精密度小于0.3%。以矮牵牛素类花青素代替矢车菊素-3-O-葡萄糖苷计算花青素含量平均提高了2.41倍,能真实地反映黑果枸杞及其制品中花青素的含量。展开更多
[目的]建立同时检测配合饲料中64种药物的超高效液相色谱-三重四极杆串联质谱(ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry,UHPLC-MS/MS)法,提高非法添加物的检测效率。[方法]采用Waters...[目的]建立同时检测配合饲料中64种药物的超高效液相色谱-三重四极杆串联质谱(ultra-high performance liquid chromatography-triple quadrupole tandem mass spectrometry,UHPLC-MS/MS)法,提高非法添加物的检测效率。[方法]采用Waters HSS T3型色谱柱(2.1 mm×100 mm,1.8μm)进行分离,流动相A为0.1%甲酸水溶液,流动相B为含0.1%甲酸的乙腈溶液,梯度洗脱,流速为0.40 mL/min,进样量为2μL;采用电喷雾离子源正离子扫描模式进行检测,多反应监测模式进行信号采集。比较4种样品提取溶剂以及2种固相萃取柱处理对目标药物的回收率,确定样品前处理的最佳方法。利用建立的UHPLC-MS/MS法对宁夏回族自治区不同来源的100批次配合饲料样品进行64种药物检测。[结果]配合饲料样品均质后,用含0.2%甲酸的乙腈水溶液(乙腈∶水=8∶2,V/V)提取,利用Oasis PRiME HLB型固相萃取柱对样品净化,多数目标药物的回收率在60%以上。64种药物在浓度为5.0~200.0μg/L的范围内线性关系良好,相关系数(R)均大于0.99;不同药物的定量限在5.0~10.0μg/kg;阳性添加5.0、20.0、50.0μg/kg 3个浓度的平均回收率在41.00%~120.49%,批内相对标准偏差(RSD)在0.54%~15.94%,批间RSD在1.25%~13.64%。在100个批次的配合饲料样品中均未检出目标药物。[结论]建立的UHPLC-MS/MS法线性关系良好、回收率高、精密度好,具有较高的重现性和较好的可操作性,可用于配合饲料中非法添加64种药物的筛查。展开更多
目的研究清瘟护肺颗粒的化学成分。方法查阅中国知网、PubMed、Web of Science等数据库,检索该制剂组方药材化学成分的相关文献,结合文献报道和ChemicalBook数据库信息,建立化学成分数据库。采用超高效液相色谱-四极杆/静电场轨道阱高...目的研究清瘟护肺颗粒的化学成分。方法查阅中国知网、PubMed、Web of Science等数据库,检索该制剂组方药材化学成分的相关文献,结合文献报道和ChemicalBook数据库信息,建立化学成分数据库。采用超高效液相色谱-四极杆/静电场轨道阱高分辨质谱(UHPLC-Q Exactive Focus MS/MS)法分析制剂的图谱数据,并以Xcalibur 4.0软件拟合分子式,与自建数据库信息进行匹配,初步推测分子式信息,与ChemicalBook或ChemSpider数据库比对,推测化学成分结构。结果共鉴定出158个化学成分,包括苷类36个,黄酮类29个,苯丙素类28个,有机酸类18个,萜类17个,色原酮类8个,其他类22个。结论所建立的方法可系统、准确、快速地定性分析清瘟护肺颗粒中的化学成分。展开更多
卤代多环芳烃(halogenated polycyclic aromatic hydrocarbons,XPAHs)是多环芳烃的氯代或溴代衍生物,因具有神经毒性、致畸变性和致癌性等特性,近年来受到广泛关注。目前,在一些环境介质(如土壤)中的XPAHs水平和分布特征等研究不够充分...卤代多环芳烃(halogenated polycyclic aromatic hydrocarbons,XPAHs)是多环芳烃的氯代或溴代衍生物,因具有神经毒性、致畸变性和致癌性等特性,近年来受到广泛关注。目前,在一些环境介质(如土壤)中的XPAHs水平和分布特征等研究不够充分,亟需发展分析检测的新方法和新技术。本研究建立了气相色谱-三重四极杆质谱(gas chromatography coupled with triple quardrupole mass spectrometry,GC-MS/MS)法定性定量分析土壤中37种XPAHs同类物,探索了GC-MS/MS分析检测XPAHs的最佳参数条件,优化了土壤样品的前处理过程,并验证了方法的有效性。结果表明,方法的检出限为0.03~1.17 pg/g,回收率为43.7%~115%。对比GC-MS/MS与高分辨气相色谱-高分辨磁质谱(high resolution gas chromatography coupled with high resolution magnetic mass spectrometry,HRGC-HRMS)的检测结果发现,其准确度和灵敏度相当,能够满足环境样品中XPAHs的定量分析要求。采用该方法分析检测采自河北地区的5个土壤样品中XPAHs,其浓度范围为648~11868 pg/g,低于此前报道的电子垃圾拆解地的土壤XPAHs水平(13.2~278 ng/g)。通过分析浓度水平和分布特征发现,土壤样品中XPAHs可能受周边工业生产等人类活动排放源的影响。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
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.
文摘利用超高效液相色谱-三重四极杆串联质谱联用法(ultra-high performance liquid chromatography-triple quadrupole mass spectrometry, UPLC-QQQ-MS)比较2种寄主肉苁蓉经过不同干燥处理后的10种苯乙醇苷类成分含量。将肉苁蓉干燥品粉碎,粉末过60目筛,用50%(体积分数)甲醇溶解后超声提取,用Agilent Eclipse Plus C18柱(2.1 mm×150 mm, 1.8μm)分离,以A相(0.1%甲酸水溶液)-B(乙腈)相作为流动相进行梯度洗脱,利用电喷雾离子源,在UPLC-QQQ-MS的动态多反应模式下检测。结果表明,不同干燥处理的寄主肉苁蓉苯乙醇苷类成分含量具有明显差异,冷冻干燥处理所得的肉苁蓉中10种苯乙醇苷类含量最高,其次为80℃烘干样品。虽然冷冻干燥对于肉苁蓉所保留10种苯乙醇苷类成分最高,但基于大规模生产考虑,80℃烘干更具有经济效益。
文摘卤代多环芳烃(halogenated polycyclic aromatic hydrocarbons,XPAHs)是多环芳烃的氯代或溴代衍生物,因具有神经毒性、致畸变性和致癌性等特性,近年来受到广泛关注。目前,在一些环境介质(如土壤)中的XPAHs水平和分布特征等研究不够充分,亟需发展分析检测的新方法和新技术。本研究建立了气相色谱-三重四极杆质谱(gas chromatography coupled with triple quardrupole mass spectrometry,GC-MS/MS)法定性定量分析土壤中37种XPAHs同类物,探索了GC-MS/MS分析检测XPAHs的最佳参数条件,优化了土壤样品的前处理过程,并验证了方法的有效性。结果表明,方法的检出限为0.03~1.17 pg/g,回收率为43.7%~115%。对比GC-MS/MS与高分辨气相色谱-高分辨磁质谱(high resolution gas chromatography coupled with high resolution magnetic mass spectrometry,HRGC-HRMS)的检测结果发现,其准确度和灵敏度相当,能够满足环境样品中XPAHs的定量分析要求。采用该方法分析检测采自河北地区的5个土壤样品中XPAHs,其浓度范围为648~11868 pg/g,低于此前报道的电子垃圾拆解地的土壤XPAHs水平(13.2~278 ng/g)。通过分析浓度水平和分布特征发现,土壤样品中XPAHs可能受周边工业生产等人类活动排放源的影响。
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.