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Optimization of magnetic field design for Hall thrusters based on a genetic algorithm

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Plasma Science and Technology 2024年第7期26卷 82-92页

作者：谭睿杭观荣王平阳 School of Mechanical Engineering Shanghai Jiaotong UniversityShanghai 200240People’s Republic of China Division of Electric propulsion Shanghai Institute of Space PropulsionShanghai 201112People’s Republic of China

Magnetic field design is essential for the operation of Hall *** study focuses on utilizing a genetic algorithm to optimize the magnetic field configuration of SPT70.A 2D hybrid PIC-DSMC and channel-wall erosion model are employed to analyze the plume divergence angle and wall erosion rate,while a Farady probe measurement and laser profilometry system are set up to verify the simulation *** results demonstrate that the genetic algorithm contributes to reducing the divergence angle of the thruster plumes and alleviating the impact of high-energy particles on the discharge channel wall,reducing the erosion by 5.5%and 2.7%,*** analysis indicates that the change from a divergent magnetic field to a convergent magnetic field,combined with the upstream shift of the ionization region,contributes to the improving the operation of the Hall thruster.

关键词： magnetic field design genetic algorithm divergence angle erosion of discharge channel convergent magnetic field

Experimental and numerical study on ignition and combustion characteristics of boron-magnesium composite powders

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Particuology 2024年第1期84卷 12-29页

作者： Shuyuan Liu Luyang Han Hongmei Liu Yingkai Song Linlin Liu Songqi Hu Science and Technology on Combustion Internal Flow and Thermo-Structure LaboratoryNorthwestern Polytechnical UniversityXi'an710072China School of Mechanical Engineering and Rail Transit Changzhou UniversityChangzhou213164China Shanghai Institute of space propulsion Shanghai201112China Shanghai Engineering Research Center of space Engine Shanghai201112China

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 *** ignition and combustion model of BM powders is established and validated in the present *** 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 ***,ignition delay time increases as pressure *** combustion time decreases with increasing Mg content and ambient pressure but increases with water *** 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 *** results show that there exists a trade-off between ignition and combustion performance of BM composite powders.

关键词： Boron magnesium powder Laser ignition Ignition and combustion model Reaction mechanism Numerical model

Wave field structure and power coupling features of blue-core helicon plasma driven by various antenna geometries and frequencies

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Chinese Physics B 2024年第3期33卷 480-487页

作者：王超刘佳苌磊卢凌峰张世杰周帆涛 State Key laboratory of Power Transmission Equipment Technology School of Electrical EngineeringChongqing UniversityChongqing 400044China Shanghai Institute of space propulsion Shanghai 201112China Southwestern Institute of Physics Chengdu 610041China

This paper deals with wave propagation and power coupling in blue-core helicon plasma driven by various antennas and *** is found that compared to non-blue-core mode,for blue-core mode,the wave can propagate in the core region,and it decays sharply outside the *** power absorption is lower and steeper in radius for blue-core *** the effects of antenna geometry for blue-core mode,it shows that half helix antenna yields the strongest wave field and power absorption,while loop antenna yields the ***,near axis,for antennas with m=+1,the wave field increases with axial *** the core region,the wave number approaches to a saturation value at much lower frequency for non-blue-core mode compared to blue-core *** total loading resistance is much lower for blue-core *** findings are valuable to understanding the physics of blue-core helicon discharge and optimizing the experimental performance of blue-core helicon plasma sources for applications such as space propulsion and material treatment.

关键词： helicon plasma helicon wave helicon discharge radio frequency plasma source

Radiative capture of proton through the ^(14)N(p,γ)^(15)O reaction at low energy

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Chinese Physics C 2024年第4期48卷 183-192页

作者： B.F.Irgaziev Abdul Kabir Jameel-Un Nabi National University of Uzbekistan Tashkent 100174Uzbekistan space and Astrophysics Research lab National Centre of GIS and Space ApplicationsDepartment of Space ScienceInstitute of Space TechnologyIslamabad 44000Pakistan University of Wah Quaid AvenueWah Cantt 47040PunjabPakistan

The CNO cycle is the main source of energy in stars more massive than our *** process defines the energy production,the duration of which can be used to determine the lifetime of massive *** cycle is an important tool for determining the age of globular *** proton capture via p+^(14)N→^(15)O+γ,at energies of astrophysical interest,is an important process in the CNO *** this project,we apply a potential model to describe both non-resonant and resonant reactions in the channels where radiative capture occurs through electric E1 *** employed the R-matrix method to describe the ongoing reactions via M1 resonant transitions,when it was not possible to correctly reproduce the experimental data using the potential *** partial components of the astrophysical S-factor are calculated for all possible electric and magnetic dipole transitions in ^(15)*** linear extrapolated S-factor at zero energy(S(0))agrees well with earlier reported values for all transition types considered in this *** on the value of the total astrophysical S-factor,depending on the collision energy,we calculate the nuclear reaction rates for p+^(14)N→^(15)O+γ.The computed rates agree well with the results reported in the NACRE II Collaboration and most recent existing measurements.

关键词： CNO cycle potential model R-matrix method cross-section astrophysical S-factor nuclear rates.

An integrative mathematical model of microwave ion thruster for mHz-frequency thrust noise analysis

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Chinese Journal of Aeronautics 2024年第4期37卷 121-136页

作者： Xiang NIU Hui LIU Daren YU Plasma propulsion laboratory Harbin Institute of TechnologyHarbin 150001China

Many high-precision space missions need thrusters to produce thrust with low noise to compensate for disturbances and ensure satellite platform stability. Microwave ion thruster is characterized with a wide thrust range and potential for these missions. A cost-effective and accurate mathematical model is crucial for mHz-frequency thrust noise analysis and feedback controller design. The Particle-In-Cell(PIC) and global models are two common simulation tools. The PIC model is characterized with high accuracy but huge computation cost, which is difficult to analyze long-time performance characteristics. Now, the global model is only used for the discharge chamber with low accuracy and cannot reflect ion extraction properties. In this paper, an integrative mathematical model is built for a 1-cm microwave ion thruster and can reflect ion beamlet divergence and impingement on the Accelerator Grid(AG). Simulation results show good agreement with experiments at 0.06 sccm. However, the model demonstrates worse consistency with experiments when the flux increases to 0.1 sccm, which may be because the influence of neutral gas on the Electron Cyclotron Resonance(ECR) is not considered in the model. A long-time(1000 s) simulation is conducted with this model under 35 μN. It takes 3 hrs, and the thrust noise reaches 1 μN/Hz^(0.5) at 1 mHz.

关键词： Electric propulsion Microwave ion thruster Integrative model Sheath property Ion beamlet divergence Thrust noise Plasma

Design,preparation,and characterization of a novel ZnO/CuO/Al energetic diode with dual functionality:Logic and destruction

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Defence Technology（防务技术） 2024年第4期34卷 57-68页

作者： Jialu Yang Jiaheng Hu Yinghua Ye Jianbing Xu Yan Hu Ruiqi Shen School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094China Micro-Nano Energetic Devices Key laboratory of MIIT Nanjing 210094China Institute of space propulsion Nanjing University of Science and TechnologyNanjing 210094China

Self-destructing chips have promising applications for securing *** paper proposes a new concept of energetic diodes for the first time,which can be used for self-destructive chips.A simple two-step electrochemical deposition method is used to prepare ZnO/CuO/Al energetic diode,in which N-type ZnO and P-type CuO are constricted to a PN *** paper comprehensively discusses the material properties,morphology,semiconductor characteristics,and exploding performances of the energetic *** results show that the energetic diode has typical rectification with a turn-on voltage of about 1.78 V and a reverse leakage current of about 3×10^(-4)*** a constant voltage of 70 V loads to the energetic diode in the forward direction for about 0.14 s or 55 V loads in the reverse direction for about 0.17 s,the loaded power can excite the energetic diode exploding and the current rises to about100 *** to the unique performance of the energetic diode,it has a double function of rectification and *** energetic diode can be used as a logic element in the normal chip to complete the regular operation,and it can release energy to destroy the chip accurately.

关键词： Energetic diode ZnO—CuO—Al thermite ZnO/CuO PN junction Electrical explosion performance Self-destructing chips

Identifying the enhancement mechanism of Al/MoO_(3) reactive multilayered films on the ignition ability of semiconductor bridge using a one-dimensional gas-solid two-phase flow model

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Defence Technology（防务技术） 2024年第3期33卷 168-179页

作者： Jianbing Xu Yuxuan Zhou Yun Shen Yueting Wang Yinghua Ye Ruiqi Shen School of Chemistry and Chemical Engineering Nanjing University of Science and TechnologyNanjing 210094China Micro-Nano Energetic Devices Key laboratory of MIIT Nanjing 210094China Institute of space propulsion Nanjing University of Science and TechnologyNanjing 210094China

Energetic Semiconductor bridge(ESCB)based on reactive multilayered films(RMFs)has a promising application in the miniature and intelligence of initiator and pyrotechnics *** the ignition enhancement mechanism of RMFs on semiconductor bridge(SCB)during the ignition process is crucial for the engineering and practical application of advanced initiator and pyrotechnics *** this study,a one-dimensional(1D)gas-solid two-phase flow ignition model was established to study the ignition process of ESCB to charge particles based on the reactivity of Al/MoO_(3) *** order to fully consider the coupled exothermic between the RMFs and the SCB plasma during the ignition process,the heat release of chemical reaction in RMFs was used as an internal heat source in this *** is found that the exothermal reaction in RMFs improved the ignition performance of *** the process of plasma rapid condensation with heat release,the product of RMFs enhanced the heat transfer process between the gas phase and the solid charge particle,which accelerated the expansion of hot plasma,and heated the solid charge particle as well as gas phase region with low *** addition,it made up for pressure loss in the gas *** the plasma dissipation process,the exothermal chemical reaction in RMFs acted as the main heating source to heat the charge particle,making the surface temperature of the charge particle,gas pressure,and gas temperature rise *** result may yield significant advantages in providing a universal ignition model for miniaturized ignition devices.

关键词： Ignition enhancement mechanism 1D gas-solid two-phase flow Al/MoO_(3)reactive multilayered films Semiconductor bridge Miniaturized ignition device

Re-analysis of temperature dependent neutron capture rates and stellarβ-decay rates of^(95-98)Mo

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Chinese Physics C 2024年第9期48卷 142-149页

作者： Abdul Kabir Jameel-Un Nabi Muhammad Tahir Abdul Muneem Zain Ul Abideen space and Astrophysics Research lab National Centre of GIS and Space ApplicationsDepartment of Space ScienceInstitute of Space TechnologyIslamabad 44000Pakistan University of Wah Quaid AvenueWah Cantt 47040PunjabPakistan Faculty of Engineering Sciences GIK Institute of Engineering Sciences and TechnologyTopi 23640Khyber PakhtunkhwaPakistan

The neutron capture rates and temperature dependent stellar beta decay rates of Mo isotopes are investigated within the framework of the statistical code TALYS v1.96 and the proton neutron quasi particle random phase approximation(pn-QRPA)*** Maxwellian average cross-section(MACS)and neutron capture rates for the^(95-98)Mo(n,γ)^(96-99)Mo radiative capture process are analyzed within the framework of the statistical code TALYS v1.96 based on the phenomenological nuclear level density model and gamma strength *** present model-based computations for the MACS are comparable to the existing measured *** sensitivity of stellar weak interaction rates to various densities and temperatures is investigated within the framework of the pn-QRPA *** attention is paid to the impact of thermally filled excited states in the decaying nuclei(^(95-98)Mo)on electron emission and positron capture ***,we compare the neutron capture rates and stellar beta decay *** is found that neutron capture rates are higher than stellar beta decay rates at both lower and higher temperatures.

关键词： cross-section TALYS nuclear level density decay rates capture rates

Research on feed-pulse collaborative control method in micro-electrical discharge machining

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Advances in Manufacturing 2024年第2期12卷 270-287页

作者： Qiang Gao Ya-Ou Zhang Xue-Cheng Xi Yuan-Ding Wang Xiao-Fei Chen Wan-Sheng Zhao School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai200240People’s Republic of China State Key laboratory of Mechanical System and Vibration Shanghai200240People’s Republic of China Shanghai Institute of space propulsion Shanghai201112People’s Republic of China

Reducing the short-circuit rate and increasing the effective discharge rate are important targets for improving the servo control effect of micro-electrical discharge machining(micro-EDM),as these two indicators are closely related to the machining efficiency and *** this study,a feed-pulse collaborative control(FPCC)method is proposed for micro-EDM based on two dimensions(space and time).In the spatial dimension,a feed control strategy with a discharge holding process is ***,in the time dimension,a forward-looking pulse control strategy is adopted,in which the pulse interval is adjusted based on a sequence analysis of feed commands and discharge *** experiments are carried out to determine the key parameters used in this method,including the discharge holding threshold and pulse interval adjustment value(T_(off_(adj))).The feed smoothness and discharge sufficiency analyses of the experimental results show that compared to the traditional double threshold average voltage method,the FPCC method reduces the number of long-distance retreats by 64%and improves the effective discharge time by 40%.

关键词： Micro-electrical discharge machining(micro-EDM) Electrode feed control Discharge pulse control Machining surface quality