As powerful torque amplification actuators, control moment gyros （CMGs） are often used in the attitude control of many state-of-the-art high resolution satellites. However, the distur- bance generated by the CMGs ca...As powerful torque amplification actuators, control moment gyros （CMGs） are often used in the attitude control of many state-of-the-art high resolution satellites. However, the distur- bance generated by the CMGs can not only reduce the attitude stability of a satellite but also dete- riorate the performance of optic payloads. Currently, CMG vibration isolators are widely used to target this problem. The isolators can affect the singularity of the CMG system as they are placed between the CMGs and the satellite bus and provide additional freedoms to the CMG system due to their flexibility. The formulation of the output torque of a CMG is studied first considering the dynamic imbalance of its spin rotor and then the deformation angle as a result of the isolator＇s flex- ibility is calculated. With the additional freedoms, the influence of isolator on the singularity problem is studied and a new steering logic to escape from the singular states is proposed.展开更多
The technological development status of new generation low cost small-lift launch vehicles applied to small satellite launch is investigated in this paper. The development trends are summarized, including low cost and...The technological development status of new generation low cost small-lift launch vehicles applied to small satellite launch is investigated in this paper. The development trends are summarized, including low cost and rapid response capability, utilization of mature rocket and missile technology, the development of mobile launch technology adopting air-based platforms and use of innovative technology. Moreover, the external power and internal demand of the small-lift launch vehicle are analyzed and the market prospect is forecasted. Finally, proposals for the development of small-lift launch vehicles are put forward, including exploration of the potential of existing rocket and missile technology, development of multi-platform mobile launch technology and further application of innovative technology and ideas.展开更多
目的了解术后谵妄(POD)的研究进展和发展趋势,为该领域后续研究提供参考依据。方法对2015年至2023年收录于Web of Science数据库中与“术后谵妄”相关的文献进行检索,采用CiteSpace 6.1.R6和VOSviewer 1.6.18软件通过文献计量学方法对...目的了解术后谵妄(POD)的研究进展和发展趋势,为该领域后续研究提供参考依据。方法对2015年至2023年收录于Web of Science数据库中与“术后谵妄”相关的文献进行检索,采用CiteSpace 6.1.R6和VOSviewer 1.6.18软件通过文献计量学方法对检索的文献进行发文趋势、发文作者、发文机构、发文国家、关键词共现、关键词聚类、关键词时间轴、关键词突现以及文献共被引进行分析。结果共有2663篇文献纳入分析,2015年至2022年,年发文量呈逐年增加的趋势,但2023年相较于2022年略有下降,发文量最多的学者是来自哈佛大学附属教学医院贝斯以色列女执事医疗中心的Marcantonio ER教授,美国是发文量最多的国家,哈佛医学院是发文量最大的机构。最高频的关键词是“危险因素”,关键词聚类结果最大是“髋部骨折”,研究时间跨度最长的聚类标签是“阿尔茨海默病”“异丙酚”和“心脏手术”,近年突现较强的关键词是“神经炎症”“细胞因子”和“生物标志物”。在共被引文献里,有4篇文献展现出较高的中心性。结论在文献计量学研究中,POD的病理生理机制及其带来的影响一直是研究的重点,特别是POD对记忆的影响以及神经炎症在谵妄发生和发展中的作用,将成为未来关注的热点。为了指导POD的个体化预防,需要进行更多的大规模研究,并加强机构间的合作力量,以提供有力的证据支持。展开更多
基金sponsored by the National Natural Science Foundation of China(No.11272172)
文摘As powerful torque amplification actuators, control moment gyros （CMGs） are often used in the attitude control of many state-of-the-art high resolution satellites. However, the distur- bance generated by the CMGs can not only reduce the attitude stability of a satellite but also dete- riorate the performance of optic payloads. Currently, CMG vibration isolators are widely used to target this problem. The isolators can affect the singularity of the CMG system as they are placed between the CMGs and the satellite bus and provide additional freedoms to the CMG system due to their flexibility. The formulation of the output torque of a CMG is studied first considering the dynamic imbalance of its spin rotor and then the deformation angle as a result of the isolator＇s flex- ibility is calculated. With the additional freedoms, the influence of isolator on the singularity problem is studied and a new steering logic to escape from the singular states is proposed.
文摘The technological development status of new generation low cost small-lift launch vehicles applied to small satellite launch is investigated in this paper. The development trends are summarized, including low cost and rapid response capability, utilization of mature rocket and missile technology, the development of mobile launch technology adopting air-based platforms and use of innovative technology. Moreover, the external power and internal demand of the small-lift launch vehicle are analyzed and the market prospect is forecasted. Finally, proposals for the development of small-lift launch vehicles are put forward, including exploration of the potential of existing rocket and missile technology, development of multi-platform mobile launch technology and further application of innovative technology and ideas.
