The effect of the radial density configuration in terms of width, edge gradient and volume gradient on the wave field and energy flow in an axially uniform helicon plasma is studied in detail. A three-parameter functi...The effect of the radial density configuration in terms of width, edge gradient and volume gradient on the wave field and energy flow in an axially uniform helicon plasma is studied in detail. A three-parameter function is employed to describe the density, covering uniform,parabolic, linear and Gaussian profiles. It finds that the fraction of power deposition near the plasma edge increases with density width and edge gradient, and decays in exponential and ＂bumpon-tail＂ profiles, respectively, away from the surface. The existence of a positive second-order derivative in the volume density configuration promotes the power deposition near the plasma core, which to our best knowledge has not been pointed out before. The transverse structures of wave field and current density remain almost the same during the variation of density width and gradient, confirming the robustness of the m=1 mode observed previously. However, the structure of the electric wave field changes significantly from a uniform density configuration, for which the coupling between the Trivelpiece-Gould（TG） mode and the helicon mode is very strong, to non-uniform ones. The energy flow in the cross section of helicon plasma is presented for the first time, and behaves sensitive to the density width and edge gradient but insensitive to the volume gradient. Interestingly, the radial distribution of power deposition resembles the radial profile of the axial component of current density, suggesting the control of the power deposition profile in the experiment by particularly designing the antenna geometry to excite a required axial current distribution.展开更多
A fluid-structure interaction system subject to Sommerfeld＇s condition is defined as a Sommerfeld system which is divided into three categories： Fluid Sommerfeld （FS） System, Solid Sommerfeld （SS） System and Flu...A fluid-structure interaction system subject to Sommerfeld＇s condition is defined as a Sommerfeld system which is divided into three categories： Fluid Sommerfeld （FS） System, Solid Sommerfeld （SS） System and Fluid Solid Sommerfeld （FSS） System of which Sommerfeld conditions are imposed on a fluid boundary only, a solid boundary only and both fluid and solid boundaries, respectively. This paper follows the previous initial results claimed by simple examples to further mathematically investigate the natural vibrations of generalized Sommerfeld systems. A new parameter representing the speed of radiation wave for generalized 3-D problems with more complicated boundary conditions is introduced into the Sommerfeld condition which allows investigation of the natural vibrations of a Sommerfeld system involving both free surface and compressible waves. The mathematical demonstrations and selected examples confirm and reveal the natural behaviour of generalized Sommerfeld systems defined above. These generalized conclusions can be used in theoretical or engineering analysis of the vibrations of various Sommerfeld systems in engineering.展开更多
首先,阐述了需求响应资源的概率分布特性,并以IES运行成本为优化目标,综合考虑电力系统、天然气系统运行约束及能量耦合约束。建立IES最优能量流(optimal energy flow,OEF)模型,用于求取发电机和耦合环节功率,并将其作为电力系统稳定器...首先,阐述了需求响应资源的概率分布特性,并以IES运行成本为优化目标,综合考虑电力系统、天然气系统运行约束及能量耦合约束。建立IES最优能量流(optimal energy flow,OEF)模型,用于求取发电机和耦合环节功率,并将其作为电力系统稳定器的输入;其次,通过搭建不同负荷水平下的暂态仿真模型,得到故障情况下的系统稳定情况;然后,提出基于堆栈降噪自动编码器(stacked denoising auto-encoders,SDAE)的电力系统稳定性评估器的训练方法;最后,在IEEE.39节点电力系统和修改的比利时20节点天然气系统组成的IES中,进行电力系统稳定性智能化评估的算例分析。仿真结果表明,基于SDAE的电力系统稳定性评估器识别精度较高,同时计算效率也较优。展开更多
基金supported by National Natural Science Foundation of China(No.11405271)
文摘The effect of the radial density configuration in terms of width, edge gradient and volume gradient on the wave field and energy flow in an axially uniform helicon plasma is studied in detail. A three-parameter function is employed to describe the density, covering uniform,parabolic, linear and Gaussian profiles. It finds that the fraction of power deposition near the plasma edge increases with density width and edge gradient, and decays in exponential and ＂bumpon-tail＂ profiles, respectively, away from the surface. The existence of a positive second-order derivative in the volume density configuration promotes the power deposition near the plasma core, which to our best knowledge has not been pointed out before. The transverse structures of wave field and current density remain almost the same during the variation of density width and gradient, confirming the robustness of the m=1 mode observed previously. However, the structure of the electric wave field changes significantly from a uniform density configuration, for which the coupling between the Trivelpiece-Gould（TG） mode and the helicon mode is very strong, to non-uniform ones. The energy flow in the cross section of helicon plasma is presented for the first time, and behaves sensitive to the density width and edge gradient but insensitive to the volume gradient. Interestingly, the radial distribution of power deposition resembles the radial profile of the axial component of current density, suggesting the control of the power deposition profile in the experiment by particularly designing the antenna geometry to excite a required axial current distribution.
文摘A fluid-structure interaction system subject to Sommerfeld＇s condition is defined as a Sommerfeld system which is divided into three categories： Fluid Sommerfeld （FS） System, Solid Sommerfeld （SS） System and Fluid Solid Sommerfeld （FSS） System of which Sommerfeld conditions are imposed on a fluid boundary only, a solid boundary only and both fluid and solid boundaries, respectively. This paper follows the previous initial results claimed by simple examples to further mathematically investigate the natural vibrations of generalized Sommerfeld systems. A new parameter representing the speed of radiation wave for generalized 3-D problems with more complicated boundary conditions is introduced into the Sommerfeld condition which allows investigation of the natural vibrations of a Sommerfeld system involving both free surface and compressible waves. The mathematical demonstrations and selected examples confirm and reveal the natural behaviour of generalized Sommerfeld systems defined above. These generalized conclusions can be used in theoretical or engineering analysis of the vibrations of various Sommerfeld systems in engineering.
文摘首先,阐述了需求响应资源的概率分布特性,并以IES运行成本为优化目标,综合考虑电力系统、天然气系统运行约束及能量耦合约束。建立IES最优能量流(optimal energy flow,OEF)模型,用于求取发电机和耦合环节功率,并将其作为电力系统稳定器的输入;其次,通过搭建不同负荷水平下的暂态仿真模型,得到故障情况下的系统稳定情况;然后,提出基于堆栈降噪自动编码器(stacked denoising auto-encoders,SDAE)的电力系统稳定性评估器的训练方法;最后,在IEEE.39节点电力系统和修改的比利时20节点天然气系统组成的IES中,进行电力系统稳定性智能化评估的算例分析。仿真结果表明,基于SDAE的电力系统稳定性评估器识别精度较高,同时计算效率也较优。
