[Objective] The present study was conducted to explore the effects of dif- ferent nitrogen sources and metal ions on the biogas production process and biogas yield by fermentation of corn stalk powder using self-desig...[Objective] The present study was conducted to explore the effects of dif- ferent nitrogen sources and metal ions on the biogas production process and biogas yield by fermentation of corn stalk powder using self-designed anaerobic fermenta- tion system. [Method] The biogas produced during fermentation was collected by water displacement, and measured by ignition. [Result] Ammonium bicarbonate, urea and yeast extract powder all increased biogas yield. Among them, ammonium bi- carbonate was the best nitrogen source. Ammonium dihydrogen phosphate showed an inhibitory effect on biogas production. Biogas yield was significantly increased by adding NaCl, KCl, MgCl2 or CaCl2, among which, NaCl had the best effect. [Conclu- sion] It is not conducive to the growth and development of methanogenic flora in the production of biogas using corn stalks as the only material in fermentation. The biogas yield can be increased by adding exogenous nitrogen, which reduces the carbon to nitrogen （C：N） ratio of fermentation materials. The biogas yield can be significantly increased by adding appropriate types and amount of electrolytes, with appropriate C：N ratio. The methanogenic flora is more tolerant to NaCl and KCl than to MgCl2 and CaCl2. Moreover, NaCl can not only significantly increase the biogas production, but also shorten startup period of methanogenic flora, thereby shortening the gas producing cycle.展开更多
Fragmentations of N2 in linearly polarized femtosecond 410 and 820 nm intense laser fields were studied by using the velocity mapping technique. Different behaviors of N2 at 410 and 820 nm were observed. Both the kine...Fragmentations of N2 in linearly polarized femtosecond 410 and 820 nm intense laser fields were studied by using the velocity mapping technique. Different behaviors of N2 at 410 and 820 nm were observed. Both the kinetic energy distributions and angular distributions of fragment ions in 410 nm field show weak dependency on laser intensities in the non- saturation regime, in contrast to the case in 820 nm. Different excited electronic states, i.e., non-Coulombic potentials populated via vertical＇excitation, are suggested to play crucial roles in fragmentations at short wavelength.展开更多
基金Supported by Innovation and Entrepreneurship Training Program for Undergraduates of Yanbian University (ydbksky2015216)~~
文摘[Objective] The present study was conducted to explore the effects of dif- ferent nitrogen sources and metal ions on the biogas production process and biogas yield by fermentation of corn stalk powder using self-designed anaerobic fermenta- tion system. [Method] The biogas produced during fermentation was collected by water displacement, and measured by ignition. [Result] Ammonium bicarbonate, urea and yeast extract powder all increased biogas yield. Among them, ammonium bi- carbonate was the best nitrogen source. Ammonium dihydrogen phosphate showed an inhibitory effect on biogas production. Biogas yield was significantly increased by adding NaCl, KCl, MgCl2 or CaCl2, among which, NaCl had the best effect. [Conclu- sion] It is not conducive to the growth and development of methanogenic flora in the production of biogas using corn stalks as the only material in fermentation. The biogas yield can be increased by adding exogenous nitrogen, which reduces the carbon to nitrogen （C：N） ratio of fermentation materials. The biogas yield can be significantly increased by adding appropriate types and amount of electrolytes, with appropriate C：N ratio. The methanogenic flora is more tolerant to NaCl and KCl than to MgCl2 and CaCl2. Moreover, NaCl can not only significantly increase the biogas production, but also shorten startup period of methanogenic flora, thereby shortening the gas producing cycle.
基金ACKNOWLEDGMENTS This work was supported by the National Natural Science Foundation of China （No.20633070 and No.20473090）.
文摘Fragmentations of N2 in linearly polarized femtosecond 410 and 820 nm intense laser fields were studied by using the velocity mapping technique. Different behaviors of N2 at 410 and 820 nm were observed. Both the kinetic energy distributions and angular distributions of fragment ions in 410 nm field show weak dependency on laser intensities in the non- saturation regime, in contrast to the case in 820 nm. Different excited electronic states, i.e., non-Coulombic potentials populated via vertical＇excitation, are suggested to play crucial roles in fragmentations at short wavelength.
