An electrochemical mass spectrometry technique was developed based on a homemade analytical device for sequential analysis of the heavy metals with various speciations in the scales.Four speciations(e.g.,water-soluble...An electrochemical mass spectrometry technique was developed based on a homemade analytical device for sequential analysis of the heavy metals with various speciations in the scales.Four speciations(e.g.,water-soluble speciation,organic speciation,indissoluble speciation and elemental speciation)of heavy metals are sequentially extracted by H_(2)O,CH_(3)OH,EDTA-2Na and electrolysis for online electrospray ionization mass spectrometry(ESI-MS)detection.The method takes significant advantages,such as requiring no tedious offline sample pretreatment,high speed of analysis(20 min),high throughput(multi-metals),good sensitivity(0.5µg/L)and rich chemical information(four speciations).As a result,the rapid comprehensive characterization of four speciations of Pb,Ni,Cu,Zn,Fe,Ba,Mn,Cr and Ca in water pipe scales has been qualitatively achieved.It demonstrated that the present method is a powerful tool for the effective assessment of potential hazards in drinking water,which provides a new analytical idea for evaluating water quality.展开更多
The dynamic stability in transverse vibration of a viscoelastic pipe for conveying puisative fluid is investigated for the simply-supported case. The material property of the beammodel pipe is described by the Kelvin-...The dynamic stability in transverse vibration of a viscoelastic pipe for conveying puisative fluid is investigated for the simply-supported case. The material property of the beammodel pipe is described by the Kelvin-type viscoelastic constitutive relation. The axial fluid speed is characterized as simple harmonic variation about a constant mean speed. The method of multiple scales is applied directly to the governing partial differential equation without discretization when the viscoelastic damping and the periodical excitation are considered small. The stability conditions are presented in the case of subharmonic and combination resonance. Numerical results show the effect of viscosity and mass ratio on instability regions.展开更多
基金This work was supported by the National Natural Science Foundation of China(Nos.21727812,21705016)the Doctoral Start-up Fund of East China University of Technology,China(No.DHBK2017115)the Open Fund of Jiangxi Provincial Key Laboratory of Mass Spectrometry Science and Instrumentation,China(No.JXMS202117).
文摘An electrochemical mass spectrometry technique was developed based on a homemade analytical device for sequential analysis of the heavy metals with various speciations in the scales.Four speciations(e.g.,water-soluble speciation,organic speciation,indissoluble speciation and elemental speciation)of heavy metals are sequentially extracted by H_(2)O,CH_(3)OH,EDTA-2Na and electrolysis for online electrospray ionization mass spectrometry(ESI-MS)detection.The method takes significant advantages,such as requiring no tedious offline sample pretreatment,high speed of analysis(20 min),high throughput(multi-metals),good sensitivity(0.5µg/L)and rich chemical information(four speciations).As a result,the rapid comprehensive characterization of four speciations of Pb,Ni,Cu,Zn,Fe,Ba,Mn,Cr and Ca in water pipe scales has been qualitatively achieved.It demonstrated that the present method is a powerful tool for the effective assessment of potential hazards in drinking water,which provides a new analytical idea for evaluating water quality.
基金Project supported by the National Natural Science Foundation of China (No.10372063).
文摘The dynamic stability in transverse vibration of a viscoelastic pipe for conveying puisative fluid is investigated for the simply-supported case. The material property of the beammodel pipe is described by the Kelvin-type viscoelastic constitutive relation. The axial fluid speed is characterized as simple harmonic variation about a constant mean speed. The method of multiple scales is applied directly to the governing partial differential equation without discretization when the viscoelastic damping and the periodical excitation are considered small. The stability conditions are presented in the case of subharmonic and combination resonance. Numerical results show the effect of viscosity and mass ratio on instability regions.
