王化蔓延:宋王朝的圣节互动——以夏丽等国及边疆诸“蛮”为例

圣节互动包含面向国外使者的圣节交聘,以及来自国内边疆诸“蛮”的圣节朝贺。圣节交聘本质上是政治的延伸与国际关系的体现,因此,随着宋夏关系的起伏,宋夏间圣节交聘亦呈现出时断时续、缺乏稳定之特点。此外,随着宋王朝国力的提升,高丽及海外诸国也会不时于圣节间前来祝寿。圣节交聘是各国间保持交流与联系的重要渠道,同时更是一种国际间权力关系的再确认。与国与国之间的圣节交聘不同,圣节朝贺指的是宋朝边疆诸“蛮”在圣节时一系列的朝拜贺寿活动。通过这些活动,边疆诸“蛮”得以表达忠心,皇权藉此扩张,圣节政治意味进而彰显。

宋代官员疾病与医疗问题探析

在漫长的人类历史中,疾病始终与人类相伴随。有宋一代,官员患病类型形形色色,致病原因多种多样。日常生活中,面对疾病威胁,官员注重未雨绸缪,积累了较为丰富的养生与防病经验;疾病发生后,官员会通过官方医疗、私人医生、宗教及巫医等方法对抗疾病。官员在疾病中的行为举措,也从侧面反映了其疾病观与处世观。

Coupling plasma plume of a low-power magnetically shielded Hall thruster with a hollow cathode

The coupling region of a Hall thruster with a hollow cathode is the region between the cathode and the thruster plume.The characteristics of plasma in that region are complicated and strongly associated with the thruster working conditions and the cathode position.In this paper,a laboratory 100 W class magnetically shielded Hall thruster was coupled with a hollow cathode.Optical imaging and electrostatic probe were employed to monitor and scan the plasma plume.Plume characteristics in the coupling region in non-self-sustained mode and self-sustained mode were compared.Evolution of the coupling plume with the cathode position was studied.Experiments show that,when turning the thruster into self-sustained mode or moving the cathode further away axially,the discharge current can be reduced by 6.4–10.6%restraining the electron current and improving ionization.In particular,when the cathode is moved further,the electron conduction near the channel walls is suppressed.The electron current is reduced by 27.4%and the ion beam current is increased by 7%.Overall,this work shows that the working mode of the thruster and the position of the cathode greatly affect the coupling plasma plume.Both play an important role in improving the utilizations of propellant and current.