The sheaths of a plasma containing two species of positive ion generated in a low pressure discharge （- mTorr） are studied using a fluid model. It is shown analytically that for the weakly collisional presheath, as ...The sheaths of a plasma containing two species of positive ion generated in a low pressure discharge （- mTorr） are studied using a fluid model. It is shown analytically that for the weakly collisional presheath, as long as the ion-ion streaming instability is absent, each ion species enters the sheath satisfying each individual Bohm criterion. The fluid equations of electrons and ions, including the time derivative terms, are solved numerically to follow the temporal evolution of the plasma and sheath. Our numerical results show that in the parameter range explored, the ion-ion streaming instability is not observed, and each ion species has its own Bohm criterion independent of the relative concentrations of the two ion species. In addition, the RF sheath is studied numerically and the similar conclusion is drawn.展开更多
The nonlinear properties of dust acoustic solitary waves in inhomogeneous dusty plasmas with two-ion temperature are investigated. By using the reductive perturbation theory, a modified variable coefficients Korteweg-...The nonlinear properties of dust acoustic solitary waves in inhomogeneous dusty plasmas with two-ion temperature are investigated. By using the reductive perturbation theory, a modified variable coefficients Korteweg-de Vries （MKdV） equation is derived. The typical integral form of the Sagdeev potential is examined numerically. The numerical results show that the inhomogeneity, the two-ion temperature have strong influence on the nonlinear properties of dust acoustic solitary waves.展开更多
通过改性由酸蚀二维蛭石制备的二维二氧化硅,得到带正电荷的二维介孔二氧化硅(PSN+)纳米片,并将PSN+用作聚环氧乙烷(PEO)基固体聚合物电解质(SPEs)的填料。由于PSN+具有丰富的正电荷,PSN^(+)与锂盐解离的阴离子能够有效结合,从而促进锂...通过改性由酸蚀二维蛭石制备的二维二氧化硅,得到带正电荷的二维介孔二氧化硅(PSN+)纳米片,并将PSN+用作聚环氧乙烷(PEO)基固体聚合物电解质(SPEs)的填料。由于PSN+具有丰富的正电荷,PSN^(+)与锂盐解离的阴离子能够有效结合,从而促进锂离子的运输,获得较好的锂离子转移数。在50℃时,基于PSN^(+)的SPEs表现出较高的离子电导率(7.5×10^(-5)S·cm^(-1)),锂离子迁移数为0.30,稳定电压窗为4.41 V。因此,组装后的LiFePO_(4)锂电池在50℃、0.2C下具有优异的初始放电比容量(155.7 m Ah·g^(-1)),在循环100次后容量保持率为97.1%。展开更多
硬炭因资源丰富、结构稳定及安全性高等优势,已成为钠离子电池常用阳极材料。其中,煤基衍生硬炭受到了广泛的关注。本工作以长焰煤为碳源,硫脲为氮硫源,NaCl为模板,通过两步炭化工艺和杂原子掺杂相结合的方法合成了N和S共掺杂的煤基硬炭...硬炭因资源丰富、结构稳定及安全性高等优势,已成为钠离子电池常用阳极材料。其中,煤基衍生硬炭受到了广泛的关注。本工作以长焰煤为碳源,硫脲为氮硫源,NaCl为模板,通过两步炭化工艺和杂原子掺杂相结合的方法合成了N和S共掺杂的煤基硬炭(NSPC1200)。两步炭化过程在调节碳微晶结构和扩大层间距方面发挥了重要的作用。N和S的共掺杂调节了炭材料的电子结构,赋予其更多的活性位点;此外,引入NaCl作为模板有助于孔结构的构建,有利于电极和电解质之间的接触,从而实现Na+和电子的有效传输。在协同作用下,样品NSPC1200表现出优异的储钠能力,在20 mA g^(−1)电流密度下呈现314.2 mAh g^(−1)的可逆容量。即使在100 mA g^(−1)下循环200次,仍保持224.4 mAh g^(−1)的比容量。这项工作成功实现了策略性调整煤基炭材料微观结构的目标,最终获得了具有优异的电化学性能的硬炭阳极。展开更多
为解决传统均衡电拓扑均衡效率较低的问题,文中提出了一种两级均衡拓扑结构。该均衡拓扑将电池组分为组内与组间两种形式,组内采用Buck-Boost均衡电路,组间采用可重构均衡电路,组内与组间可同时均衡,提高了均衡效率。以SOC(State of Cha...为解决传统均衡电拓扑均衡效率较低的问题,文中提出了一种两级均衡拓扑结构。该均衡拓扑将电池组分为组内与组间两种形式,组内采用Buck-Boost均衡电路,组间采用可重构均衡电路,组内与组间可同时均衡,提高了均衡效率。以SOC(State of Charge)作为均衡变量,组内均衡算法采用基于SOC的模糊逻辑控制策略,减少均衡时间,提高均衡效率。使用MATLAB/Simulink软件对电路拓扑建模仿真,并与传统Buck-Boost电路进行对比。仿真结果表明,在充放电状态下,相较于传统Buck-Boost电路,所提算法及均衡拓扑使均衡时间减少了约28%,表明该均衡电路及算法具有良好的性能。展开更多
文摘The sheaths of a plasma containing two species of positive ion generated in a low pressure discharge （- mTorr） are studied using a fluid model. It is shown analytically that for the weakly collisional presheath, as long as the ion-ion streaming instability is absent, each ion species enters the sheath satisfying each individual Bohm criterion. The fluid equations of electrons and ions, including the time derivative terms, are solved numerically to follow the temporal evolution of the plasma and sheath. Our numerical results show that in the parameter range explored, the ion-ion streaming instability is not observed, and each ion species has its own Bohm criterion independent of the relative concentrations of the two ion species. In addition, the RF sheath is studied numerically and the similar conclusion is drawn.
基金supported by National Natural Science Foundation of China(No.10975114)the Science-Technology Foundation of Gansu Province of China(No.1014RJZA017)the Prominent Youth Foundation of LUT,China(No.0910ZXC082)
文摘The nonlinear properties of dust acoustic solitary waves in inhomogeneous dusty plasmas with two-ion temperature are investigated. By using the reductive perturbation theory, a modified variable coefficients Korteweg-de Vries （MKdV） equation is derived. The typical integral form of the Sagdeev potential is examined numerically. The numerical results show that the inhomogeneity, the two-ion temperature have strong influence on the nonlinear properties of dust acoustic solitary waves.
文摘通过改性由酸蚀二维蛭石制备的二维二氧化硅,得到带正电荷的二维介孔二氧化硅(PSN+)纳米片,并将PSN+用作聚环氧乙烷(PEO)基固体聚合物电解质(SPEs)的填料。由于PSN+具有丰富的正电荷,PSN^(+)与锂盐解离的阴离子能够有效结合,从而促进锂离子的运输,获得较好的锂离子转移数。在50℃时,基于PSN^(+)的SPEs表现出较高的离子电导率(7.5×10^(-5)S·cm^(-1)),锂离子迁移数为0.30,稳定电压窗为4.41 V。因此,组装后的LiFePO_(4)锂电池在50℃、0.2C下具有优异的初始放电比容量(155.7 m Ah·g^(-1)),在循环100次后容量保持率为97.1%。
文摘硬炭因资源丰富、结构稳定及安全性高等优势,已成为钠离子电池常用阳极材料。其中,煤基衍生硬炭受到了广泛的关注。本工作以长焰煤为碳源,硫脲为氮硫源,NaCl为模板,通过两步炭化工艺和杂原子掺杂相结合的方法合成了N和S共掺杂的煤基硬炭(NSPC1200)。两步炭化过程在调节碳微晶结构和扩大层间距方面发挥了重要的作用。N和S的共掺杂调节了炭材料的电子结构,赋予其更多的活性位点;此外,引入NaCl作为模板有助于孔结构的构建,有利于电极和电解质之间的接触,从而实现Na+和电子的有效传输。在协同作用下,样品NSPC1200表现出优异的储钠能力,在20 mA g^(−1)电流密度下呈现314.2 mAh g^(−1)的可逆容量。即使在100 mA g^(−1)下循环200次,仍保持224.4 mAh g^(−1)的比容量。这项工作成功实现了策略性调整煤基炭材料微观结构的目标,最终获得了具有优异的电化学性能的硬炭阳极。
文摘为解决传统均衡电拓扑均衡效率较低的问题,文中提出了一种两级均衡拓扑结构。该均衡拓扑将电池组分为组内与组间两种形式,组内采用Buck-Boost均衡电路,组间采用可重构均衡电路,组内与组间可同时均衡,提高了均衡效率。以SOC(State of Charge)作为均衡变量,组内均衡算法采用基于SOC的模糊逻辑控制策略,减少均衡时间,提高均衡效率。使用MATLAB/Simulink软件对电路拓扑建模仿真,并与传统Buck-Boost电路进行对比。仿真结果表明,在充放电状态下,相较于传统Buck-Boost电路,所提算法及均衡拓扑使均衡时间减少了约28%,表明该均衡电路及算法具有良好的性能。
