Accurate thrust assessment is crucial for characterizing the performance of micro-thrusters.This paper presents a comprehensive evaluation of the thrust generated by a needle-type indium field emission electric propul...Accurate thrust assessment is crucial for characterizing the performance of micro-thrusters.This paper presents a comprehensive evaluation of the thrust generated by a needle-type indium field emission electric propulsion(In-FEEP)micro-thruster using three methods based on a pendulum:direct thrust measurement,indirect plume momentum transfer and beam current diagnostics.The experimental setup utilized capacitive displacement sensors for force detection and a voice coil motor as a feedback actuator,achieving a resolution better than 0.1μN.Key performance factors such as ionization and plume divergence of ejected charged particles were also examined.The study reveals that the high applied voltage induces significant electrostatic interference,becoming the dominant source of error in direct thrust measurements.Beam current diagnostics and indirect plume momentum measurements were conducted simultaneously,showing strong agreement within a deviation of less than 0.2N across the operational thrust range.The results from all three methods are consistent within the error margins,verifying the reliability of the indirect measurement approach and the theoretical thrust model based on the electrical parameters of In-FEEP.展开更多
基金Project supported by the National Key Research and Development Program of China(Grant No.2020YFC2201001)the Guangdong Major Project of Basic and Applied Basic Research(Grant No.2019B030302001)+1 种基金the National Natural Science Foundation of China(Grant Nos.12105373,12105374,and 11927812)the Science and Technology Research Project of Jiangxi Provincial Department of Education(Grant No.GJJ2402105).
文摘Accurate thrust assessment is crucial for characterizing the performance of micro-thrusters.This paper presents a comprehensive evaluation of the thrust generated by a needle-type indium field emission electric propulsion(In-FEEP)micro-thruster using three methods based on a pendulum:direct thrust measurement,indirect plume momentum transfer and beam current diagnostics.The experimental setup utilized capacitive displacement sensors for force detection and a voice coil motor as a feedback actuator,achieving a resolution better than 0.1μN.Key performance factors such as ionization and plume divergence of ejected charged particles were also examined.The study reveals that the high applied voltage induces significant electrostatic interference,becoming the dominant source of error in direct thrust measurements.Beam current diagnostics and indirect plume momentum measurements were conducted simultaneously,showing strong agreement within a deviation of less than 0.2N across the operational thrust range.The results from all three methods are consistent within the error margins,verifying the reliability of the indirect measurement approach and the theoretical thrust model based on the electrical parameters of In-FEEP.
文摘目的:了解苏州地区儿童呼吸道人类博卡病毒(hBoV)混合感染的情况及混合感染后的临床特征。方法:选取2012-2015年苏州大学附属儿童医院呼吸科因呼吸道感染住院的患儿8 711例,收集鼻咽分泌物,应用实时PCR检测hBoV,逆转录-聚合酶链反应法(RT-PCR)检测人类偏肺病毒(h MPV)、人类鼻病毒(hRV),直接免疫荧光法检测呼吸道7种常见病毒包括呼吸道合胞病毒(RSV)、流感病毒A(InfA)、InfB、副流感病毒1型(PinfⅠ)、PinfⅡ、PinfⅢ、腺病毒(ADV)。结果:8 711例标本中,hBoV阳性358例(4.11%)。358例hBoV阳性患儿中,92例(25.70%)存在混合感染,常见混合的病原为hRV、RSV和PinfⅢ。与单纯hBoV感染患儿相比,hBoV混合感染患儿月龄小(15.8个月vs 20.3个月)、入院前病程长(12.1 d vs 9.5 d)、喘息发生率高(63.04%vs 48.12%)(P均<0.05),但两组患儿气促、呼吸困难、紫绀及住院时间比较差异均无统计学意义(P均>0.05)。结论:苏州地区儿童hBoV存在一定比例的混合感染,但混合感染并不加重病情。
