Article
Materials Science, Multidisciplinary
Haotian Fan, Yishen Xu, Lei Wang, Liqiu Wei, Hong Li, Ning Guo, Yongjie Ding
Summary: This study explores the effects of unsymmetrical magnetic fields on the discharge characteristics of Hall thrusters with a large height-radius ratio. The results show that the thruster can achieve stable discharge and improved performance under unsymmetrical magnetic fields. Inward-inclined magnetic fields enhance discharge efficiency, while outward-inclined magnetic fields prolong the thruster's service life. However, unsymmetrical magnetic fields lead to an increase in plume divergence angle.
Article
Physics, Multidisciplinary
Shengtao Liang, Hui Liu, Daren Yu
Summary: Experimental and simulation research were conducted on the cylindrical Hall thruster by comparing different discharge channel configurations. The expanding cross-section channel design showed poor performance due to reduced propellant density. The mixed cross-section channel had better propellant utilization, but ionization region shift led to insufficient potential drop for ion acceleration, resulting in lower thrust and anode efficiency compared to the straight channel.
Article
Engineering, Aerospace
Haotian Fan, Zhiguo Chen, Yongjie Ding, Liqiu Wei, Hong Li, Daren Yu
Summary: The use of a permanent magnet can effectively reduce the radial size of a Hall thruster, and a design with a large height-radius ratio can significantly improve the thruster's performance. Numerical simulations have shown that an optimized design structure can increase ionization concentration and performance utilization rate, reduce wall losses and plume divergence, thereby improving overall discharge performance.
Article
Physics, Fluids & Plasmas
Guangchuan Zhang, Junxue Ren, Haibin Tang, Zhe Zhang, Jinbin Cao
Summary: This study successfully implemented an asymmetric magnetic field configuration in a Hall thruster using a trim coil, and investigated its effects on the performance of the thruster. The experimental results showed that an outward deflected magnetic field could improve the efficiency of the thruster, reduce discharge oscillations, and enhance propellant utilization efficiency.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2022)
Article
Physics, Fluids & Plasmas
Dongho Lee, Guentae Doh, Holak Kim, Laurent Garrigues, Wonho Choe
Summary: Two distinct discharge modes were observed in a 50 W-class micro-Hall thruster plasma under different operating conditions. In mode B, the thruster showed performance improvements in terms of thrust, specific impulse, and anode efficiency, suggesting that operation is more advantageous in mode B than in mode A for the utilization of such low-power Hall thrusters.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2021)
Article
Engineering, Aerospace
Xingyu Liu, Hong Li, Zhongkai An, Yongjie Ding, Liqiu Wei, Daren Yu, Wei Mao
Summary: A new wall material was employed to improve the performance of Hall thrusters, and it was found that the length of the metallic wall significantly affects the thruster efficiency.
Article
Engineering, Aerospace
Yuanyuan Gao, Weizong Wang, Shuwen Xue, Yifei Li, Guobiao Cai
Summary: This paper investigates the effects of upstream magnetic mirror fields on the plume characteristics of full cylindrical Hall thrusters. The experiments show that the axial gradient value of the magnetic mirror field has a significant impact on the plasma discharge region and plume angle. The analysis reveals that the observed plasma discharge near the thruster exhaust is related to the extension of the ionization region under a low magnetic mirror field, while a larger magnetic mirror field enhances propellant utilization and current utilization, resulting in higher ion energy and a more collimated plume.
Article
Materials Science, Multidisciplinary
Shengtao Liang, Hui Liu, Daren Yu
Summary: The article introduces the potential of cusped field thrusters with electron cyclotron resonance discharge enhancement in the micro-Newton propulsion field, and compares the configurations and performances of different-stage thrusters.
Article
Materials Science, Multidisciplinary
Lei Wang, Yishen Xu, Yongjie Ding, Fan Xu, Limeng Bao, Yan Meng, Hong Li, Liqiu Wei, Daren Yu
Summary: In this study, the effects of the peak magnetic field location on the discharge characteristics of a 100-W Hall thruster with large-gradient magnetic field were investigated. It was found that the thruster performance significantly improves when the peak magnetic field is closer to the channel exit.
Article
Physics, Fluids & Plasmas
Christopher L. Sercel, Tate M. Gill, Benjamin A. Jorns
Summary: The induced magnetic field during acceleration in a pulsed rotating magnetic field (RMF) thruster is experimentally investigated. The plasma currents induced in the thruster are shown to be able to form a field-reversed configuration plasmoid, and the Lorentz force resulting from the induced magnetic field contributes to about 25% of the measured thrust.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2023)
Article
Chemistry, Multidisciplinary
Matthew Baird, Thomas Kerber, Ron McGee-Sinclair, Kristina Lemmer
Summary: The study investigated the performance of a 44-mm-diameter Western Hall Thruster (WHT44) by independently varying parameters such as anode flow, discharge voltage, magnet current, and cathode flow fraction (CFF). Increasing anode flow led to an increase in plasma plume divergence angle, while discharge voltage, magnet current, and CFF had the opposite effect. The oscilloscope captured discharge oscillation behavior, showing a strong oscillation near 90 kHz, and the noise frequency spectra became more broadbanded at specific CFF values.
APPLIED SCIENCES-BASEL
(2021)
Article
Nanoscience & Nanotechnology
Nannan Li, Yue Liu, Chao Liu, Mingyang Wu
Summary: The effect of the background magnetic field on plasma characteristics in a Hall thruster has been investigated numerically. The research shows that the background magnetic field significantly influences the distribution of plasma density, electron power absorption, electron current density, and other plasma parameters.
Article
Physics, Fluids & Plasmas
Yuanyuan Gao, Weizong Wang, Yifei Li, Guobiao Cai, Shuwen Xue
Summary: There are two distinct discharge modes in a 200 W cylindrical Hall thruster with the near-anode cusp magnetic field. In mode I, a divergent plume is observed at a low discharge voltage, while a convergent plume (mode II) is observed when the discharge voltage rises over 280 V, accompanied by a decrease in discharge current and electron current and narrowing of plume angle. These novel mode transition phenomena should be attributed to the unique near-anode cusp magnetic field.
PLASMA SOURCES SCIENCE & TECHNOLOGY
(2022)
Article
Engineering, Aerospace
J. M. Tejeda, A. Knoll
Summary: An investigation on an oxygen-fuelled Hall Effect Thruster was conducted to study the effects of different discharge channel axial lengths, ceramic walls, and anode materials. The study found that a channel length of 13.1 mm performed the best in terms of thrust, specific impulse, and thrust efficiency. The impact of different wall materials and anode materials on the thruster's performance was also analyzed.
Article
Materials Science, Multidisciplinary
Yuanyuan Gao, Weizong Wang, Kai Zhang, Yifei Li, Guobiao Cai
Summary: This paper studies the ionization characteristics and mechanism of two magnetic field configurations, and finds that there exists an additional ionization mechanism in the opposite polarity configuration, which may be the main cause for the enhancement of propellant utilization efficiency and narrowing of the ion energy distribution function curves.
Article
Materials Science, Multidisciplinary
Ping Zhang, Xiujie Yue, Yeran Gao, Zhenyong Lin, Shunxiang Wang, Songting Zhang
Summary: This paper investigates the strengthening mechanism of highspeed cutting and solid particle-entrained waterjet peening (HSC-WJP) composite reinforcement on 7075-T6 aluminum alloy. The research results show that composite reinforcement can improve surface quality, reduce surface pits and roughness, and decrease the size of precipitation-free zone (PFZ) at grain boundaries.
Article
Materials Science, Multidisciplinary
Sangyoon Lee, Hwi Yoon, Sanghun Lee, Seung-min Chung, Hyungjun Kim
Summary: The wettability of metal oxides, particularly HfO2 thin films deposited via atomic layer deposition, and its correlation with surface free energy have been studied. It was found that surface oxygen species significantly affect the intrinsic hydrophilicity of HfO2 thin films, and the crystalline orientations also evolve with film thickness.
Article
Materials Science, Multidisciplinary
Changdong Yin, Yiwen Wu, Zhou Xu, Dongdong Ye, Jun Yao, Jianjun Chen, Qiang Liu, Xin Ge, Meiling Ding
Summary: This study proposed a new strategy to indirectly estimate the hydrogen diffusivity of metallic materials under tensile stress by combining the electrochemical hydrogen permeation test (EHPT), the hydrogen diffusion descriptive equation based on Fick's law, and hydrogen pre-charged tensile test. The results showed that the hydrogen permeation curve obtained was highly approximate to the theoretical trend. The hydrogen embrittlement (HE) susceptibility of the specimens increased with increasing stress.
Article
Materials Science, Multidisciplinary
Huan Luo, Wei-yi Wang, Xin Yu, Xian-jun Lei, Lang Liu, Guo-zheng Zha, Wen-long Jiang, Bin Yang, Bao-qiang Xu
Summary: Separating selenium and tellurium is a general challenge in material and non-ferrous metallurgical industries. This paper proposes a novel method that achieved efficient separation of selenium and tellurium using gas-liquid equilibrium phase diagram and valence regulation-vacuum gasification technique.
Article
Materials Science, Multidisciplinary
Fan Zhang, Rong Xin Wang, Aiqin Tian, Fangzhi Li, Jianping Liu, Hui Yang
Summary: Deposition of Pd/Pt/Au three-layer films on p-GaN under high and ultra-high vacuum conditions was studied to investigate the electrical contact properties. Linear I-V curves were observed in samples deposited under ultra-high vacuum conditions, while nonlinear I-V characteristics were obtained in samples deposited under high vacuum conditions. The study also found that the samples deposited under high vacuum conditions had higher amounts of oxygen and Pd oxide. The oxide layer had an additional influence on the electrical characteristics of the Pd/Pt/Au/p-GaN contact.
Article
Materials Science, Multidisciplinary
Hongli Liu, Chengzhe Liu, Ying Sui, Zhongxian Liu, Tiangang Zhang, Zhiqiang Zhang, Shuang Sun, Jianwei Jia
Summary: This study utilized polysiloxane and hafnium carbide to produce Si-N-C-O-Hf hybridized ceramic fibers, and obtained ceramic fibers with hemispherical particles on the surface through electrostatic spinning and pyrolysis. The ceramic fibers exhibited excellent thermal stability, oxidation resistance, and high temperature insulation.
Article
Materials Science, Multidisciplinary
M. Abaker, Nazar Elamin Ahmed, A. Saad, H. F. Khalil, E. M. M. Ibrahim, A. M. Adam
Summary: This paper systematically studied the internal structure and thermoelectric properties of In1-xGaxSb alloys prepared by melting synthesis at 1123 K. The results showed that doping with Ga in the In sites led to a significant increase in the Seebeck coefficient and power factor, while reducing the thermal conductivity. The maximum dimensionless figure of merit was observed at 403 K.
Article
Materials Science, Multidisciplinary
Fucheng Yu, Jinlong Ren, Jielin Zhang, Haiyang Chen, Xin Tian, Chenchen Feng, Cuixia Li, Jianbin Zhang, Xianxi Tang, Xiaogang Hou
Summary: An environmentally friendly ZnO@BiVO4 composite photocatalyst was prepared using in-situ self-assembly and solvothermal methods, demonstrating good photocatalytic performance. The mass ratio of BiVO4 and NCZ was found to influence the photocatalytic performance of the composite.
Article
Materials Science, Multidisciplinary
Yaoming Shao, Pingping Zheng, Tianhao Dong, Lianghuan Wei, Haifei Wu, Jianxiao Si
Summary: In this paper, Mg3Bi2 films were prepared on glass substrate using magnetron sputtering, and the phase composition and thermoelectric properties of the films were investigated with different atomic ratios. The films displayed a metastable cubic phase and high conductivity when the atomic ratio exceeded stoichiometry.
Article
Materials Science, Multidisciplinary
I. V. Uimanov, D. L. Shmelev, S. A. Barengolts
Summary: A two-dimensional axisymmetric model has been developed to study the prebreakdown processes in a cathode microprotrusion under an external electric field. The simulation results show that electrohydrodynamic instability leads to the formation of a nanometer-sized conical protrusion on the microprotrusion tip, significantly accelerating the heating process.
Article
Materials Science, Multidisciplinary
Weilun Zhang, Di Yang, Feng Gong, Yongjun Chen, Tian Chen, Zhiwen Xie, Sirui Yang
Summary: A novel Pt doping method was designed to improve the thermal stability of CrWN coating. The doping of Pt atoms effectively blocks the coherent growth of the grains and creates a significant mixing effect, resulting in a smooth surface with uniform element distribution.
Article
Materials Science, Multidisciplinary
Xiaoye Wang, Xiaoguang Yang, Wenna Du, Tao Yang
Summary: In this study, the effects of multiple growth parameters on self-catalyzed growth of InAs/GaSb axial heterostructured nanowires on Si substrate by MOCVD were investigated. It was found that the growth temperature and switching time have significant influences on the nanowire growth.
Article
Materials Science, Multidisciplinary
Weizhong Cui, Yan Zhao, Can Cui, Xing Liu, Beili Pang, Jianguang Feng, Hongzhou Dong, Liyan Yu, Lifeng Dong
Summary: This study introduces Co2+ cations into Cs2AgBiBr6 film to improve its quality, grain size, and conductivity, resulting in enhanced solar cell efficiency.
Article
Materials Science, Multidisciplinary
Jian Wang, Ke Yang, Xianming Cheng, Yalin Lu, Ganghui Wu, Yang Zhang, Yun Kan
Summary: The corrosion behavior and microstructural evolution of Sc microalloyed Al-3.2Cu-1.5Li alloys were investigated in detail. The microstructural results showed higher levels of dislocations density in the Sc microalloyed sample, which resulted in significantly refined grains and T1 precipitates. Microalloying with Sc changed the corrosion mode of the alloy and localized corrosion was found to occur preferentially at the subgrain within unrecrystallized grains with high grain stored energy.
Article
Materials Science, Multidisciplinary
Weifeng Liu, Na Liu, Kaiqiang Song, Meiqin Zeng, Zhongchen Lu
Summary: Monoclinic WO3 prepared through plasma milling exhibits higher photocatalytic activity due to its higher surface area, increased oxygen vacancies, and defects.
