Two multicapillary coluumns(SE 30 and Carbowax 20M)were used for high speed GC separation of positional isomers of industrial chemicals The performances of the two multicapillary columns were also evaluated,such a...Two multicapillary coluumns(SE 30 and Carbowax 20M)were used for high speed GC separation of positional isomers of industrial chemicals The performances of the two multicapillary columns were also evaluated,such as the effects of carrier velocity,column temperature and sample capacity Two typical explosive isomers(DNT and TNT)were well separated on SE 30 multicapillary column,while some important chemicals(e g xylenes,xylenols)were separated on Carbowax 20M multicapillary column at high speed The multimulticapillary column shows the feature of fast analysis,relatively lower column temperature and larger sample capacity展开更多
Air or inert atmosphere irradiation of liquid normal alkanes C5-C8 and benzene by electron beam was carried out. Oxidation （in the air） or isomerization （in the inert gases） of liquid normal alkanes under electron...Air or inert atmosphere irradiation of liquid normal alkanes C5-C8 and benzene by electron beam was carried out. Oxidation （in the air） or isomerization （in the inert gases） of liquid normal alkanes under electron beam was shown. Action of electron beam on benzene molecules in the air or in the inert atmosphere leads to biphenyl, terphenyl and polymers. Irradiation by the bunch of electrons of mixture hexane with 10% benzene reduced to firm fractions （fullerene＇s similar structures） in a deposit.展开更多
The purpose of this paper is to present a novel way to building quantitative structure-property relationship(QSPR) models for predicting the gas-to-benzene solvation enthalpy(ΔHSolv) of 158 organic compounds based on...The purpose of this paper is to present a novel way to building quantitative structure-property relationship(QSPR) models for predicting the gas-to-benzene solvation enthalpy(ΔHSolv) of 158 organic compounds based on molecular descriptors calculated from the structure alone. Different kinds of descriptors were calculated for each compounds using dragon package. The variable selection technique of enhanced replacement method(ERM) was employed to select optimal subset of descriptors. Our investigation reveals that the dependence of physico-chemical properties on solvation enthalpy is a nonlinear observable fact and that ERM method is unable to model the solvation enthalpy accurately. The standard error value of prediction set for support vector machine(SVM) is 1.681 kJ ? mol^(-1) while it is 4.624 kJ ? mol^(-1) for ERM. The results established that the calculated ΔHSolvvalues by SVM were in good agreement with the experimental ones, and the performances of the SVM models were superior to those obtained by ERM one. This indicates that SVM can be used as an alternative modeling tool for QSPR studies.展开更多
The authors studied the changes in the electrical properties of PANI （polyaniline） when exposed to the presence of N20 （nitrous oxide）. The techniques used to determine the adsorption of gas in the polymer were th...The authors studied the changes in the electrical properties of PANI （polyaniline） when exposed to the presence of N20 （nitrous oxide）. The techniques used to determine the adsorption of gas in the polymer were the electrochemical impedance, steps voltammetry and transmission electron microscopy. The objective of this work was to determine the ability of adsorption and desorption of PANI to be used as sensor in an open environment. Measurements were performed in a controlled atmosphere, temperature and flux. The gas was passed through a glass capsule in which an electrochemical cell was designed with copper electrodes and PANI as electrolyte. The change in electrical properties of the material is analyzed using a potentiostat/galvanostat in situ. Subsequently, the material was analyzed by TEM （Transmission Electron Microscopy） elemental analysis. The measurements were performed with difl^rent concentrations of N20 with a purity of 99%. As a result of measurements, it was found that the change in electrical resistance of PANI is caused by the physical interaction that occurs when in contact with NzO and even a change in the morphology of polymer, however, the binding is weak and sufficient to increase the temperature at which 25% PANI film regains its original properties.展开更多
The bilayer poly(ethylene oxide)/multiple-walled carbon nanotubes(PEO/MWCNTs) and three-layer PEO/MWCNTs/PEO composite thin films were fabricated with the spraying process on the interdigitated transducers(IDTs) as ga...The bilayer poly(ethylene oxide)/multiple-walled carbon nanotubes(PEO/MWCNTs) and three-layer PEO/MWCNTs/PEO composite thin films were fabricated with the spraying process on the interdigitated transducers(IDTs) as gas sensors for toluene-sensing application.Compared with the bilayer thin film sensor,the sensor with three-layer thin films exhibited higher response values and better recovery property.The microstructures of sensing films were characterized by scanning electron microscopy(SEM) to indicate that the better sensing response of three-layer thin films might be ascribed to the sufficient adsorption of toluene molecules on the surfaces of upper and bottom PEO films.The selectivity of the three-layer film sensor was further investigated by comparing responses upon exposure to different interference vapors with the response to toluene exposure,and much higher response was observed in the case of toluene.Good repeatability of the three-layer film sensor was also observed.展开更多
Molecular mechanics(MM) and the gradually reduced size(GRS) techniques were used to construct the crystalline poly-p-xylylene(PPX) films,including PPX N,PPX C and PPX D.The corresponding chain-end area of crystalline ...Molecular mechanics(MM) and the gradually reduced size(GRS) techniques were used to construct the crystalline poly-p-xylylene(PPX) films,including PPX N,PPX C and PPX D.The corresponding chain-end area of crystalline PPX films provides enough free volumes for adsorbing and transferring gas molecules.Then,the permeable properties of gases were calculated using Grand Canonical Monte Carlo(GCMC),NVT-Molecular Dynamics(MD) and cluster analysis methods.The calculated diffusion coefficients are in the same order of magnitude over a range of temperatures and pressures.And there is no permeation property of gases in the inner part of the crystalline PPX films.展开更多
文摘Two multicapillary coluumns(SE 30 and Carbowax 20M)were used for high speed GC separation of positional isomers of industrial chemicals The performances of the two multicapillary columns were also evaluated,such as the effects of carrier velocity,column temperature and sample capacity Two typical explosive isomers(DNT and TNT)were well separated on SE 30 multicapillary column,while some important chemicals(e g xylenes,xylenols)were separated on Carbowax 20M multicapillary column at high speed The multimulticapillary column shows the feature of fast analysis,relatively lower column temperature and larger sample capacity
文摘Air or inert atmosphere irradiation of liquid normal alkanes C5-C8 and benzene by electron beam was carried out. Oxidation （in the air） or isomerization （in the inert gases） of liquid normal alkanes under electron beam was shown. Action of electron beam on benzene molecules in the air or in the inert atmosphere leads to biphenyl, terphenyl and polymers. Irradiation by the bunch of electrons of mixture hexane with 10% benzene reduced to firm fractions （fullerene＇s similar structures） in a deposit.
文摘The purpose of this paper is to present a novel way to building quantitative structure-property relationship(QSPR) models for predicting the gas-to-benzene solvation enthalpy(ΔHSolv) of 158 organic compounds based on molecular descriptors calculated from the structure alone. Different kinds of descriptors were calculated for each compounds using dragon package. The variable selection technique of enhanced replacement method(ERM) was employed to select optimal subset of descriptors. Our investigation reveals that the dependence of physico-chemical properties on solvation enthalpy is a nonlinear observable fact and that ERM method is unable to model the solvation enthalpy accurately. The standard error value of prediction set for support vector machine(SVM) is 1.681 kJ ? mol^(-1) while it is 4.624 kJ ? mol^(-1) for ERM. The results established that the calculated ΔHSolvvalues by SVM were in good agreement with the experimental ones, and the performances of the SVM models were superior to those obtained by ERM one. This indicates that SVM can be used as an alternative modeling tool for QSPR studies.
文摘The authors studied the changes in the electrical properties of PANI （polyaniline） when exposed to the presence of N20 （nitrous oxide）. The techniques used to determine the adsorption of gas in the polymer were the electrochemical impedance, steps voltammetry and transmission electron microscopy. The objective of this work was to determine the ability of adsorption and desorption of PANI to be used as sensor in an open environment. Measurements were performed in a controlled atmosphere, temperature and flux. The gas was passed through a glass capsule in which an electrochemical cell was designed with copper electrodes and PANI as electrolyte. The change in electrical properties of the material is analyzed using a potentiostat/galvanostat in situ. Subsequently, the material was analyzed by TEM （Transmission Electron Microscopy） elemental analysis. The measurements were performed with difl^rent concentrations of N20 with a purity of 99%. As a result of measurements, it was found that the change in electrical resistance of PANI is caused by the physical interaction that occurs when in contact with NzO and even a change in the morphology of polymer, however, the binding is weak and sufficient to increase the temperature at which 25% PANI film regains its original properties.
基金supported by the National Natural Science Foundation of China(Grant Nos.61176066 and 61101031)
文摘The bilayer poly(ethylene oxide)/multiple-walled carbon nanotubes(PEO/MWCNTs) and three-layer PEO/MWCNTs/PEO composite thin films were fabricated with the spraying process on the interdigitated transducers(IDTs) as gas sensors for toluene-sensing application.Compared with the bilayer thin film sensor,the sensor with three-layer thin films exhibited higher response values and better recovery property.The microstructures of sensing films were characterized by scanning electron microscopy(SEM) to indicate that the better sensing response of three-layer thin films might be ascribed to the sufficient adsorption of toluene molecules on the surfaces of upper and bottom PEO films.The selectivity of the three-layer film sensor was further investigated by comparing responses upon exposure to different interference vapors with the response to toluene exposure,and much higher response was observed in the case of toluene.Good repeatability of the three-layer film sensor was also observed.
基金supported by the National Natural Science foundation of China (Grant Nos.11011120241 and 11076002)the One Hundred Talents Project Foundation Program,the Western Light Joint Scholar Foundation Program of Chinese Academy of Sciences (Grant No. Y12S311301)+1 种基金the Western Light Joint Scholar Foundation Program of Chinese Academy of SciencesChina Academy of Engineering Physics "Double Hundred Talents Project" candidates optional subjects (Grant No. 2008Rc01)
文摘Molecular mechanics(MM) and the gradually reduced size(GRS) techniques were used to construct the crystalline poly-p-xylylene(PPX) films,including PPX N,PPX C and PPX D.The corresponding chain-end area of crystalline PPX films provides enough free volumes for adsorbing and transferring gas molecules.Then,the permeable properties of gases were calculated using Grand Canonical Monte Carlo(GCMC),NVT-Molecular Dynamics(MD) and cluster analysis methods.The calculated diffusion coefficients are in the same order of magnitude over a range of temperatures and pressures.And there is no permeation property of gases in the inner part of the crystalline PPX films.
