This paper describes the quantitative determination of rare-earth elements cerium, dysprosium and non-rare-earth element copper, lead and the homogeneity examination of these four elements in yttrium oxide reference m...This paper describes the quantitative determination of rare-earth elements cerium, dysprosium and non-rare-earth element copper, lead and the homogeneity examination of these four elements in yttrium oxide reference material by isotope dilution spark source mass spectrometry (ID-SSMS). The sensitivity of the meth- od is l0^(-5)～10^(-7%). The precision is better than 6%. The accuracy is better than 5%. The interferences of the spectra and the optimum amount of the spike added to the sample are discussed. The choice of the conducting material for the sample electrodes is studied.展开更多
This study deals with the first application of the isotope dilution - inductively coupled plasma mass spectrometry in the rhenium-osmium geochronometry in China. The chemical separation procedure included decompositio...This study deals with the first application of the isotope dilution - inductively coupled plasma mass spectrometry in the rhenium-osmium geochronometry in China. The chemical separation procedure included decomposition of samples by means of alkali fusion, extraction of rhenium by acetone and extraction of osmium by distillation. The recovery of both elements in the entire process was more than 90% . The blanks of analyses were 0.07 ng for rhenium and 0.01 ng for 187Os. The mineralization ages of molybdenites from four molybdenum deposits in China were determined by using this method, with a precision (2σ)of about ±3% . These results agree satisfactorily with their geological backgrounds. The Re-Os method can directly determine ages of metal deposits and reflect the true ages more reliably than other dating methods that only determine the ages of country rocks from which mineralization ages are inferred. As many hydrothermal sulphide deposits usually contain molybdenites, this method has bright prospects of wide application.展开更多
A simplified one-dimensional transient model for biomass pyrolysis in a fixed bed cylindrical reactor has been formulated and experiments have been carded out to verify the calculation results regarding temperature di...A simplified one-dimensional transient model for biomass pyrolysis in a fixed bed cylindrical reactor has been formulated and experiments have been carded out to verify the calculation results regarding temperature distribu- tion. The mathematical model accounts for mass, momentum and heat transfer, including moisture evaporation and convection of pyrolysis gases. Numerical simulation has allowed to predict temperature and heat flux distri- bution, and the dynamics of feedstock devolatilization. Special attention has been devoted to the analysis of the effect of biomass moisture content on the pyrolysis process. The model of moisture vaporization in biomass bed was proposed, which included structure of surface of biomass particles. Assuming that vaporization occurs on the border of the dry and wet areas of the bed, the flux of water vaporization depends on the specific surface area of the particles and overall heat flux.展开更多
文摘This paper describes the quantitative determination of rare-earth elements cerium, dysprosium and non-rare-earth element copper, lead and the homogeneity examination of these four elements in yttrium oxide reference material by isotope dilution spark source mass spectrometry (ID-SSMS). The sensitivity of the meth- od is l0^(-5)～10^(-7%). The precision is better than 6%. The accuracy is better than 5%. The interferences of the spectra and the optimum amount of the spike added to the sample are discussed. The choice of the conducting material for the sample electrodes is studied.
基金This research was supported jointly by the Foundation for Development of Geological Science and Technology (Project No. 49173164)
文摘This study deals with the first application of the isotope dilution - inductively coupled plasma mass spectrometry in the rhenium-osmium geochronometry in China. The chemical separation procedure included decomposition of samples by means of alkali fusion, extraction of rhenium by acetone and extraction of osmium by distillation. The recovery of both elements in the entire process was more than 90% . The blanks of analyses were 0.07 ng for rhenium and 0.01 ng for 187Os. The mineralization ages of molybdenites from four molybdenum deposits in China were determined by using this method, with a precision (2σ)of about ±3% . These results agree satisfactorily with their geological backgrounds. The Re-Os method can directly determine ages of metal deposits and reflect the true ages more reliably than other dating methods that only determine the ages of country rocks from which mineralization ages are inferred. As many hydrothermal sulphide deposits usually contain molybdenites, this method has bright prospects of wide application.
基金partially financed from the project "Agro-energy complexes as an example of dispersed co- generation based on local renewable energy sources" (POIG.01.01.02-00-016/08) within the framework of Programme "Innowacyjna Gospodarka 2007-2013"
文摘A simplified one-dimensional transient model for biomass pyrolysis in a fixed bed cylindrical reactor has been formulated and experiments have been carded out to verify the calculation results regarding temperature distribu- tion. The mathematical model accounts for mass, momentum and heat transfer, including moisture evaporation and convection of pyrolysis gases. Numerical simulation has allowed to predict temperature and heat flux distri- bution, and the dynamics of feedstock devolatilization. Special attention has been devoted to the analysis of the effect of biomass moisture content on the pyrolysis process. The model of moisture vaporization in biomass bed was proposed, which included structure of surface of biomass particles. Assuming that vaporization occurs on the border of the dry and wet areas of the bed, the flux of water vaporization depends on the specific surface area of the particles and overall heat flux.
