Based on rate equations, a theoretical model of a fiber oscillator with a multimode gain fiber was built. We studied the effect of the rare earth doping profile in the core on the output characteristics of the multimo...Based on rate equations, a theoretical model of a fiber oscillator with a multimode gain fiber was built. We studied the effect of the rare earth doping profile in the core on the output characteristics of the multimode fiber oscillator. The results indicated that a pure fundamental mode can be obtained by partly doping the core of the large mode area （LMA） ytterbium doped fiber （YDF） in the fiber laser. Furthermore, a sole specific high-order mode can also be implemented by tailoring the rare earth doping profile according to the simulations. The mode coupling effect was also taken into account in the model. In spite of the mode coupling effect, the specific mode was able to dominate in the output of the fiber laser by utilizing the designed LMA YDF.展开更多
The effects of neodymium application mode on the disease index, PAL, POD and PPO activity, content of lignin and generation rate of ·O2^- in cucumbers were investigated by pot experiment. The results suggest that...The effects of neodymium application mode on the disease index, PAL, POD and PPO activity, content of lignin and generation rate of ·O2^- in cucumbers were investigated by pot experiment. The results suggest that the disease index decreases after spraying Nd^3＋. Relative protection effects of at-the-same-time-group, induced-group and therapy-group are 7.51%, 27.14% and 11.51%. The PAL activity of Nd ＋ Fo treatment in at-the-same-time-group, induced-group and therapy-group increases by 9.86%, 48.57% and 4.97% respectively compared with that of Fo treatment. The POD activity decreases by 27.52%, 35.87% and 7.67%. The PPO activity increases by 5.75%, 36.58% and 52.19%. The ·O2^- generation rate decreases by 9.49%, 28.08% and 25. 21%.展开更多
文摘Based on rate equations, a theoretical model of a fiber oscillator with a multimode gain fiber was built. We studied the effect of the rare earth doping profile in the core on the output characteristics of the multimode fiber oscillator. The results indicated that a pure fundamental mode can be obtained by partly doping the core of the large mode area （LMA） ytterbium doped fiber （YDF） in the fiber laser. Furthermore, a sole specific high-order mode can also be implemented by tailoring the rare earth doping profile according to the simulations. The mode coupling effect was also taken into account in the model. In spite of the mode coupling effect, the specific mode was able to dominate in the output of the fiber laser by utilizing the designed LMA YDF.
文摘The effects of neodymium application mode on the disease index, PAL, POD and PPO activity, content of lignin and generation rate of ·O2^- in cucumbers were investigated by pot experiment. The results suggest that the disease index decreases after spraying Nd^3＋. Relative protection effects of at-the-same-time-group, induced-group and therapy-group are 7.51%, 27.14% and 11.51%. The PAL activity of Nd ＋ Fo treatment in at-the-same-time-group, induced-group and therapy-group increases by 9.86%, 48.57% and 4.97% respectively compared with that of Fo treatment. The POD activity decreases by 27.52%, 35.87% and 7.67%. The PPO activity increases by 5.75%, 36.58% and 52.19%. The ·O2^- generation rate decreases by 9.49%, 28.08% and 25. 21%.
