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Tailoring precipitation-strengthening in Ir-based ternary alloys:a first-principles approach to L1_(2) phase engineering
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作者 Xian-Pei Jiang Wei Yu +6 位作者 Yan Wei Hai-Jun Wu Ji-Ping Ding Chang-Yi Hu Xing-Jun Liu Jing Feng Xiao-Yu Chong 《Rare Metals》 2025年第11期9036-9052,共17页
Iridium(Ir)-based superalloys withγ/γ'twophase microstructure are recognized as next-generation high-temperature materials for aerospace engines operating above 1500℃.The strengthening phases can markedly enhan... Iridium(Ir)-based superalloys withγ/γ'twophase microstructure are recognized as next-generation high-temperature materials for aerospace engines operating above 1500℃.The strengthening phases can markedly enhance the mechanical strength of alloys.However,these phases exhibit significant brittleness,and their properties in Ir-based alloys remain insufficiently investigated.Here,the high-throughput calculations were employed to screen the potentialγ'phases for Ir_(3)X(X=Al,Si,Sc,Ti,V,Cr,Mn,Fe,Co,Ni,Cu,Zn,Y,Zr,Nb,Mo,Tc,Ru,Rh,Pd,Ag,Cd,La,Hf,Ta,W,Re,Os,Pt,Au,Th)through systematic assessment of phase stability,melting points,shear modulus and anti-phase boundary(APB)energies.Subsequently,lattice misfit was further optimized through thirdelement compositional design in Ir_(3)(Ti_(0.5)X_(0.5))(X=Nb,Hf,Zr,Ta).The dependence of yield strength on precipitate size was systematically evaluated through the precipitation strengthening effect.Ir_(3)(Ti_(0.5)Ta_(0.5))displays a reduced lattice misfit(0.63%),accompanied by a higher shear modulus(207 GPa),elevated APB energy(920 mJ m^(-2)),and an increased Poisson's ratio(0.25),demonstrating a synergistic improvement in these interrelated mechanical characteristics.The increase of density of states value at Fermi level and the right-shift of the peak in the bonding region result in the improved ductility.The greatest delocalization degree of electrons around Ta and the shorter Ir-Ta bond lengths are responsible for its higher shear modulus and APB energies.A novel Ir_(3)(Ti_(0.5)Ta_(0.5))composition balancing the trade-off between high strength and ductility is expected to guide the development of Irbased superalloys. 展开更多
关键词 Iridium-based superalloys First-principles calculations L1_(2)phase Shear modulus Anti-phase boundary Precipitation strengthening
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Simulation study on the influence of the peeling material position on the discharge process of a Hall thruster 被引量:1
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作者 Yizhou JIN Siyuan DONG +2 位作者 Bo YU Yan ZHANG Peng MIAO 《Plasma Science and Technology》 2025年第6期69-77,共9页
The deposition layer on the discharge channel wall of a Hall thruster after long-term operation occasionally detaches from the wall and interferes with the plasma inside the channel,resulting in current pulse and thre... The deposition layer on the discharge channel wall of a Hall thruster after long-term operation occasionally detaches from the wall and interferes with the plasma inside the channel,resulting in current pulse and threatening the power supply.To understand the generation mechanism of the current pulse,the interaction between the peeling material and the channel plasma was studied by the particle-in-cell and Monte Carlo collision(PIC/MCC)method.The plasma evolution and distribution in the Hall thruster channel when peeling material existed were simulated.Simulation results show that the peeling material changes the electron transportation and ionization,and the effects are related to the position of the peeling material.When the peeling material invades the zone where the ionization rate is originally the highest without peeling material,the ionization process is almost terminated.The ionization suppression by the peeling material will cause the propellant gas to refill the channel exit.As the peeling material moves away,gas discharge is induced near the channel exit,resulting in anode current pulse. 展开更多
关键词 Hall thruster peeling material discharge disturbance PIC simulation
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Study on Transient Flow Characteristics of Attitude Control Engine During Starting Process
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作者 HUANG Jian 《Aerospace China》 2022年第3期15-22,共8页
Liquid bipropellant attitude control rocket engines are widely used in satellites,manned spaceships,deep space probes and other spacecraft.The performance of an attitude control engine is directly related to the lifet... Liquid bipropellant attitude control rocket engines are widely used in satellites,manned spaceships,deep space probes and other spacecraft.The performance of an attitude control engine is directly related to the lifetime,control precision and safety of a spacecraft.The study of flow characteristics of an engine transient process is important to improve its performance.In this paper,the transient flow test of a transparent test piece was carried out during the starting process of the attitude control engine.Then the transient process of the test piece was simulated and compared with the test results to verify the rationality of the simulation model.Transient flow simulation was carried out for the starting process of the real engine injector.The results show that the filling of the outer ring of the oxidant circuit is slower than that of the central collecting cavity,and the filling of the second layer of the outer ring is slower than that of the first layer.The filling process in the fuel path starts from the cooling hole near the inlet side and the fuel flows out in the circumferential direction.Installation direction has little influence on engine starting flow process in the ground state.The filling time of the engine in its vacuum state is longer than that in the ground state,the filling time of oxidizer is 31%longer than that in ground state,and the filling time of fuel is 57%longer than that in ground state. 展开更多
关键词 attitude control engine starting process TRANSIENT flow characteristics
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Design and fabrication of a full elastic sub-micron-Newton scale thrust measurement system for plasma micro thrusters 被引量:6
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作者 Zhongkai Zhang Guanrong Hang +5 位作者 Jiayun Qi Zun Zhang Zhe Zhang Jiubin Liu Wenjiang Yang Haibin Tang 《Plasma Science and Technology》 SCIE EI CAS CSCD 2021年第10期29-39,共11页
In this work,a force measurement system is proposed to measure the thrust of plasma microthruster with thrust magnitude ranging from sub-micro-Newtons to hundreds micro-Newtons.The thrust measurement system uses an el... In this work,a force measurement system is proposed to measure the thrust of plasma microthruster with thrust magnitude ranging from sub-micro-Newtons to hundreds micro-Newtons.The thrust measurement system uses an elastic torsional pendulum structure with a capacitance sensor to measure the displacement,which can reflect the position change caused by the applied force perpendicular to the pendulum axis.In the open-loop mode,the steady-state thrust or the impulse of the plasma micro-thruster can be obtained from the swing of the pendulum,and in the closed-loop mode the steady-state thrust can be obtained from the feedback force that keeps the pendulum at a specific position.The thrust respond of the system was calibrated using an electrostatic weak force generation device.Experimental results show that the system can measure a thrust range from 0 to 200μN in both open-loop mode and closed-loop mode with a thrust resolution of 0.1μN,and the system can response to a pulse bit at the magnitude of 0.1 m N s generated by a micro cathode arc thruster.The background noise of the closed-loop mode is lower than that of the open-loop mode,both less than 0.1 m N/Hz in the range of 10 mHz to 5 Hz. 展开更多
关键词 plasma thruster micro-thrust measurement torsional pendulum
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Facile fabrication of CeO_2 hollow microspheres with yeast as bio-templates 被引量:2
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作者 牟广宇 魏清莲 黄永民 《Journal of Rare Earths》 SCIE EI CAS CSCD 2015年第12期1329-1334,共6页
CeO2 hollow microspheres were prepared through a facile method by using yeast cells as bio-templates. The yeast pro- vided a solid flame for the deposition of cerium hydroxide to form the hybrid Ce(OH)3@yeast precur... CeO2 hollow microspheres were prepared through a facile method by using yeast cells as bio-templates. The yeast pro- vided a solid flame for the deposition of cerium hydroxide to form the hybrid Ce(OH)3@yeast precursor. The resulting CeO2 hollow microspheres were obtained by calcining the precursor. The products were characterized by field emission scanning electron micros- copy (FE-SEM), transmission electron microscopy (TEM), X-ray powder diffraction (XRD), fourier transform infrared spectroscopy (FTIR), N2 adsorption/desorption analysis, X-ray photoelectron spectrum (XPS) and H2 temperature programmed reduction (H2-TPR) It was found that the products fully retained the morphology of the yeast cells and the size of the hollow microspheres was about 1.5-2 μm. The catalytic test results showed that the as-obtained hollow CeO2 microspheres possessed a higher catalytic activity in CO oxidation than the commercial CeO2, which attributed to their higher surface area, hollow structure and superior reducibility. This study provided a promising route for the preparation of a variety of other inorganic hollow microspheres. 展开更多
关键词 bio-template CEO2 hollow spheres CO oxidation rare earths
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Numerical investigation of low cycle fatigue life for channel wall nozzles 被引量:1
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作者 CHENG Cheng WANG Yibai +1 位作者 LIU Yu LIN Qingguo 《航空动力学报》 EI CAS CSCD 北大核心 2018年第7期1553-1565,共13页
The thermal-structural response and low cycle fatigue life of a three-dimensional(3D)channel wall nozzle with regenerative cooling were numerically investigated by coupling the finite volume fluid-thermal method,nonli... The thermal-structural response and low cycle fatigue life of a three-dimensional(3D)channel wall nozzle with regenerative cooling were numerically investigated by coupling the finite volume fluid-thermal method,nonlinear finite element thermal-structural analysis and local strain methods.The nozzle had a high area ratio(nozzle exit area divided by throat area)under cyclic working loads.Parametric studies were carried out to evaluate the effects of channel structural parameters such as channel width,channel height,liner thickness and rib width.Results showed that the integrated effects of three-dimensional channel structure and load distribution caused serious strain,which mainly occurred at the intersectant regions of liner wall on the gas side and the symmetric planes of channel and rib.The cooling effect and channel structural strength were significantly improved as the channel width and height decreased,leading to substantial extension of the nozzle service life.On the other hand,the successive decrease in liner thickness and rib width apparently increased the strain amplitude and residual strain of channel wall nozzle during cyclic work,significantly shortening the service life.The present work is of value for design of the channel wall nozzle to prolong its cyclic service life. 展开更多
关键词 liquid propellant rocket engine low cycle fatigue channel wall nozzle regenerative cooling nonlinear structural analysis finite element method
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Study on High Power Hall Electric Propulsion Technology 被引量:3
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作者 HANG Guanrong ZHAO Zhen +7 位作者 YU Shuilin QIAO Caixia LIU Jia HUANG Hao TIAN Leichao LI Lin LI Wenshuai KANG Xiaolu 《Aerospace China》 2020年第2期31-38,共8页
High power Hall electric propulsion technology is a very competitive electric propulsion technology for future large space missions such as large GEO satellites,manned space programs,deep space explorations,cargo ship... High power Hall electric propulsion technology is a very competitive electric propulsion technology for future large space missions such as large GEO satellites,manned space programs,deep space explorations,cargo ships,space tugs.Based on the experience of more than 20 years in research and development of Hall electric propulsion,the Shanghai Institute of Space Propulsion(SISP)has developed 3 high power Hall thrusters,i.e.,the 10 k W class HET-500,20 k W class HET-1000,and 50 k W class HET-3000.This paper presents the development status of the high power(≥10 k W)Hall electric propulsion at SISP,including tests of 3 high power Hall thrusters in the power range from 10 k W to 50 k W,the qualification of a single string of a 10 k W Hall electric propulsion system,and the study of a cluster of two 1.35 k W HET-80 Hall thrusters to understand the technical issues related to multi-thruster high power electric propulsion systems. 展开更多
关键词 high power Hall electric propulsion Hall thruster single string system integration thruster cluster
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Electron population properties with different energies in a helicon plasma source
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作者 Zun ZHANG Zhe ZHANG +1 位作者 Haibin TANG Jiting OUYANG 《Plasma Science and Technology》 SCIE EI CAS CSCD 2021年第1期48-55,共8页
The characteristics of electrons play a dominant role in determining the ionization and acceleration processes of plasmas.Compared with electrostatic diagnostics,the optical method is independent of the radio frequenc... The characteristics of electrons play a dominant role in determining the ionization and acceleration processes of plasmas.Compared with electrostatic diagnostics,the optical method is independent of the radio frequency(RF)noise,magnetic field,and electric field.In this paper,an optical emission spectroscope was used to determine the plasma emission spectra,electron excitation energy population distributions(EEEPDs),growth rates of low-energy and highenergy electrons,and their intensity jumps with input powers.The 56 emission lines with the highest signal-to-noise ratio and their corresponding electron excitation energy were used for the translation of the spectrum into EEEPD.One discrete EEEPD has two clear different regions,namely the low-energy electron excitation region(neutral lines with threshold energy of13–15 eV)and the high-energy electron excitation region(ionic lines with threshold energy?19 e V).The EEEPD variations with different diameters of discharge tubes(20 mm,40 mm,and 60 mm)and different input RF powers(200–1800 W)were investigated.By normalized intensity comparison of the ionic and neutral lines,the growth rate of the ionic population was higher than the neutral one,especially when the tube diameter was less than 40 mm and the input power was higher than 1000 W.Moreover,we found that the intensities of low-energy electrons and high-energy electrons jump at different input powers from inductively coupled(H)mode to helicon(W)mode;therefore,the determination of W mode needs to be carefully considered. 展开更多
关键词 electric propulsion helicon plasma plasma diagnostics optical emission spectroscope electron excitation energy population distribution
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Particle motion and enrichment behavior of dense granular impinging-jets generated by the nozzle with rectangular orifice
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作者 Ting Li Qingguo Lin +2 位作者 Haokun Liu Shengju Wang Weifeng Li 《Particuology》 2025年第1期312-327,共16页
Particle motion regime and enrichment behavior of dense granular impinging-jets formed by the nozzle with rectangular orifice are experimentally and numerically investigated.Two impingement patterns are identified,inc... Particle motion regime and enrichment behavior of dense granular impinging-jets formed by the nozzle with rectangular orifice are experimentally and numerically investigated.Two impingement patterns are identified,including long and short parallel patterns.Particles enrich in the central axis of the granular sheet when two jets impinge with the long axes parallel pattern.While at the short axes parallel pattern,particles generate two symmetrical enriched streams.The angle of particle-enriched streams is observed to increase with increasing angle of two impinging-jets and decreasing aspect ratio of the nozzle orifice.The particle image velocity(PIV)analysis results demonstrate that the circumferential distribution of the particle velocity on the granular sheet follows the Gaussian distribution.With the formation of particle-enriched streams,the concentration distribution of the particle evolves into a trimodal pattern.Results of the discrete element method(DEM)indicate that the core region with low velocity within the impact zone of impinging-jets generated by using two nozzles with rectangular orifices extends into a shuttle shape.The core region develops and extends along the horizontal(or vertical)directions at long(or short)axes impingement pattern,thereby,affecting the enrichment behavior of particles. 展开更多
关键词 Dense granular impinging-jet Enrichment behavior Rectangular orifice
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Experimental and numerical study on ignition and combustion characteristics of boron-magnesium composite powders 被引量:4
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作者 Shuyuan Liu Luyang Han +3 位作者 Hongmei Liu Yingkai Song Linlin Liu Songqi Hu 《Particuology》 SCIE EI CAS CSCD 2024年第1期12-29,共18页
A high-pressure laser ignition and combustion system with adjustable oxidizer gas atmosphere is established to investigate the ignition and combustion characteristics of boron-magnesium(BM)com-posite powders.An igniti... A high-pressure laser ignition and combustion system with adjustable oxidizer gas atmosphere is established to investigate the ignition and combustion characteristics of boron-magnesium(BM)com-posite powders.An ignition and combustion model of BM powders is established and validated in the present study.The results show that increasing water content,O_(2) content and Mg content all result in shorter ignition delay time of BM powders,among which the effect of water content is the most obvious.However,ignition delay time increases as pressure increases.The combustion time decreases with increasing Mg content and ambient pressure but increases with water content.With the increase of O_(2) content,combustion time of BM powders first increases and then decreases,which means a critical O_(2) content exists above which combustion time decreases.The results show that there exists a trade-off between ignition and combustion performance of BM composite powders. 展开更多
关键词 Boron magnesium powder Laser ignition Ignition and combustion model Reaction mechanism Numerical model
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Optical analysis method for fast plasma characterization of high-speed miniaturized synthetic jet
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作者 Ye Yuan Yan Zhang +4 位作者 Cheng Guo Xiaolu Kang Zhong Yan Xiaoping Huang Qing Zhao 《Chinese Optics Letters》 SCIE EI CAS CSCD 2022年第7期41-46,共6页
In this paper,a new optical analysis method for plasma characterization is proposed.Plasma characteristics are obtained directly by measuring the plasma luminous color,rather than the complex spectral diagnosis method... In this paper,a new optical analysis method for plasma characterization is proposed.Plasma characteristics are obtained directly by measuring the plasma luminous color,rather than the complex spectral diagnosis method,which is difficult to obtain at high speed.By using the light transmittance curve of the human cornea,the RGB coordinates are calculated from the measured plasma spectrum data.Plasma characteristics are diagnosed using the Boltzmann plot method and the Stark broadening method.The corresponding relationship of the electron temperature,electron density data points,and luminous color is established and analyzed.Our research results indicate that this optical analysis method is feasible and promising for fast plasma characterization. 展开更多
关键词 optical analysis method plasma characteristics spectral diagnosis high-speed miniaturized actuator
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