The basic principle of fly ash triboelectrification is analysed. The mineral electrical index and test method are introduced. The electric difference of different mineral composition of fly ash is discussed by analysi...The basic principle of fly ash triboelectrification is analysed. The mineral electrical index and test method are introduced. The electric difference of different mineral composition of fly ash is discussed by analysis of chemical and mineral composition of fly ash in Xinwen power plant. The dielectric constant and charge-mass ratio of carbon and ash of fly ash are tested. Combined with the experimental study on rotary triboelectrostatic separation, the charged characteristic of fly ash particles with different size is gained. The results show that the dielectric constant of fly ash with different grain size decreased with the decrease of particle size, which lead to the poor electrical conductivity, Thus it can be seen that par- ticle size plays a leading role in conductivity, The charge of carbon and ash with each size increased with the decreased of particle size; and the charge-mass ratio between carbon and ash with the same size lar- ger with the decrease of size, which indicated that the finer particle size, the more favorable for triboelec- trification separation. In the same conditions, the best decarburization effect is realized when the particle size ranges from 0.038 to 0.074 ram, whose decarbonization rate and efficiency index reached 38.93% and 120.83% respectively.展开更多
A nonlinear and non-averaged model of a two-beam free-electron laser （FEL） wiggler that is tapered nonlinearly in the absence of slippage is presented. The two beams are assumed to have different energies, and the f...A nonlinear and non-averaged model of a two-beam free-electron laser （FEL） wiggler that is tapered nonlinearly in the absence of slippage is presented. The two beams are assumed to have different energies, and the fundamental resonance of the higher energy beam is at the third harmonic of the lower energy beam. By using Maxwell＇s equations and the full Lorentz force equation of motion for the electron beams, coupled differential equations are derived and solved numerically by the fourth-order Runge-Kutta method. The amplitude of the wiggler field is assumed to decrease nonlinearly when the saturation of the third harmonic occurs. By simulation, the optimum starting point of the tapering and the slopes for reducing the wiggler amplitude are found. This technique can be applied to substantially improve the efficiency of the two-beam FEL in the XUV and X-ray regions. The effect of tapering on the dynamical stability of the fast electron beam is also studied.展开更多
P-A1GaN/P-GaN superlattices are investigated in blue InGaN light-emitting diodes as electron blocking layers. The simulation results show that efficiency droop is markedly improved due to two reasons： （i） enhanced ...P-A1GaN/P-GaN superlattices are investigated in blue InGaN light-emitting diodes as electron blocking layers. The simulation results show that efficiency droop is markedly improved due to two reasons： （i） enhanced hole concentration and hole carrier transport efficiency in A1GaN/GaN superlattices, and （ii） enhanced blocking of electron overflow between multiple quantum-wells and A1CaN/GaN superlattices.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51274200 and 51221462)
文摘The basic principle of fly ash triboelectrification is analysed. The mineral electrical index and test method are introduced. The electric difference of different mineral composition of fly ash is discussed by analysis of chemical and mineral composition of fly ash in Xinwen power plant. The dielectric constant and charge-mass ratio of carbon and ash of fly ash are tested. Combined with the experimental study on rotary triboelectrostatic separation, the charged characteristic of fly ash particles with different size is gained. The results show that the dielectric constant of fly ash with different grain size decreased with the decrease of particle size, which lead to the poor electrical conductivity, Thus it can be seen that par- ticle size plays a leading role in conductivity, The charge of carbon and ash with each size increased with the decreased of particle size; and the charge-mass ratio between carbon and ash with the same size lar- ger with the decrease of size, which indicated that the finer particle size, the more favorable for triboelec- trification separation. In the same conditions, the best decarburization effect is realized when the particle size ranges from 0.038 to 0.074 ram, whose decarbonization rate and efficiency index reached 38.93% and 120.83% respectively.
文摘A nonlinear and non-averaged model of a two-beam free-electron laser （FEL） wiggler that is tapered nonlinearly in the absence of slippage is presented. The two beams are assumed to have different energies, and the fundamental resonance of the higher energy beam is at the third harmonic of the lower energy beam. By using Maxwell＇s equations and the full Lorentz force equation of motion for the electron beams, coupled differential equations are derived and solved numerically by the fourth-order Runge-Kutta method. The amplitude of the wiggler field is assumed to decrease nonlinearly when the saturation of the third harmonic occurs. By simulation, the optimum starting point of the tapering and the slopes for reducing the wiggler amplitude are found. This technique can be applied to substantially improve the efficiency of the two-beam FEL in the XUV and X-ray regions. The effect of tapering on the dynamical stability of the fast electron beam is also studied.
基金Project supported by the Project of Combination of Production and Research Guided by Education Ministry of China in 2009(Grant No. 2009B090300338)the LED Industrial Projects of Special Funds Strategic Emerging Industries in 2011,Guangdong Province,China (Grant No. 2010A081002005)
文摘P-A1GaN/P-GaN superlattices are investigated in blue InGaN light-emitting diodes as electron blocking layers. The simulation results show that efficiency droop is markedly improved due to two reasons： （i） enhanced hole concentration and hole carrier transport efficiency in A1GaN/GaN superlattices, and （ii） enhanced blocking of electron overflow between multiple quantum-wells and A1CaN/GaN superlattices.
