Nanometer sized SnO 2 particles were prepared by a sol gel method using inorganic salt as a precursor material. Its crystallization was investigated by means of TG DTA,IR absorption spectra, X ray diffractometry ...Nanometer sized SnO 2 particles were prepared by a sol gel method using inorganic salt as a precursor material. Its crystallization was investigated by means of TG DTA,IR absorption spectra, X ray diffractometry and TEM as well as its resistivity change and the gas sensitivity varied with temperature were measured in various reducing gas. The results indicate that well crystallized nano sized SnO 2 with size around 15nm can be obtained at annealing temperature 600℃. The activation energy for the growth of nano SnO 2 was calculated to be 26.55kJ.mol 1 when the annealing temperature was higher than 500℃. The measurements also show that there is a peculiar resistance change varied with temperature for nano SnO 2.It has relevance to the increase in surface adsorbed oxygen. The selective detectivities to C 4H 10 and petrol can be increased when ruthenium ion was doped in nano SnO 2 as a catalyst and so do the gas sensitivity to CO,CH 4,H 2 etc. when rhodium ion was doped in.The detection to the several reducing gas can be realized when the temperature ranged from 260℃ to 400℃.展开更多
Particle exchange molecular dynamics (PEMD) simulation technique is proposed to study the gas-liquid phase diagram of fluids. In the simulations, the fluid parti-cles can be transferred between the two coupled boxes, ...Particle exchange molecular dynamics (PEMD) simulation technique is proposed to study the gas-liquid phase diagram of fluids. In the simulations, the fluid parti-cles can be transferred between the two coupled boxes, which possess constant total number of particles and volume. The particle transfer is controlled by the difference of chemical potential in the respective simulation box. After equilibrium the two boxes have the same pressure, temperature and chemical potential. The method is further used to study the gas-liquid phase diagram of Stockmayer fluid. Increasing the dipole strength will enhance the critical temperature. The predicted critical points are in agreement with those from Gibbs ensemble Monte Carlo simulations, while the small systematic difference is attributed to the system size effects and the thermostat methods.展开更多
文摘Nanometer sized SnO 2 particles were prepared by a sol gel method using inorganic salt as a precursor material. Its crystallization was investigated by means of TG DTA,IR absorption spectra, X ray diffractometry and TEM as well as its resistivity change and the gas sensitivity varied with temperature were measured in various reducing gas. The results indicate that well crystallized nano sized SnO 2 with size around 15nm can be obtained at annealing temperature 600℃. The activation energy for the growth of nano SnO 2 was calculated to be 26.55kJ.mol 1 when the annealing temperature was higher than 500℃. The measurements also show that there is a peculiar resistance change varied with temperature for nano SnO 2.It has relevance to the increase in surface adsorbed oxygen. The selective detectivities to C 4H 10 and petrol can be increased when ruthenium ion was doped in nano SnO 2 as a catalyst and so do the gas sensitivity to CO,CH 4,H 2 etc. when rhodium ion was doped in.The detection to the several reducing gas can be realized when the temperature ranged from 260℃ to 400℃.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.20304015 and 20404005)for the GeneralMajor Programs(Grant No.20490220)subsidized by the Young Teacher Fund of Jilin University.
文摘Particle exchange molecular dynamics (PEMD) simulation technique is proposed to study the gas-liquid phase diagram of fluids. In the simulations, the fluid parti-cles can be transferred between the two coupled boxes, which possess constant total number of particles and volume. The particle transfer is controlled by the difference of chemical potential in the respective simulation box. After equilibrium the two boxes have the same pressure, temperature and chemical potential. The method is further used to study the gas-liquid phase diagram of Stockmayer fluid. Increasing the dipole strength will enhance the critical temperature. The predicted critical points are in agreement with those from Gibbs ensemble Monte Carlo simulations, while the small systematic difference is attributed to the system size effects and the thermostat methods.
