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Plasma Science and Technology 2024年第8期26卷 58-63页

作者：余乐怡陆文琪张丽娜 Key laboratory of materials modification by Laser Ionand Electron Beams(Ministry of Education)School of PhysicsDalian University of TechnologyDalian 116024People’s Republic of China

The self-excited second harmonic in radio-frequency capacitively coupled plasma was significantly enhanced by adjusting the external variable *** a lower pressure of 3 Pa,the excitation of the second harmonic caused an abnormal transition of the electron energy probability function,resulting in abrupt changes in the electron density and *** changes in the electron energy probability function as well as the electron density and temperature were not observed at the higher pressure of 16 Pa under similar harmonic *** phenomena are related to the influence of the second harmonic on stochastic heating,which is determined by both amplitude and the relative phase of the *** results suggest that the self-excited high-order harmonics must be considered in practical applications of lowpressure radio-frequency capacitively coupled plasmas.

关键词： radio-frequency capacitively coupled plasma harmonics the electron energy probability function

Power transfer efficiency in an air-breathing radio frequency ion thruster

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Chinese Physics B 2024年第7期33卷 430-438页

作者：黄高煌李宏高飞王友年 Key laboratory of materials modification by Laser Ionand Electron Beams(Ministry of Education)School of PhysicsDalian University of TechnologyDalian 116024China College of Physical Science and Technology Dalian UniversityDalian 116622China

Due to a series of challenges such as low-orbit maintenance of satellites, the air-breathing electric propulsion has got widespread attention. Commonly, the radio frequency ion thruster is favored by low-orbit missions due to its high specific impulse and efficiency. In this paper, the power transfer efficiency of the radio frequency ion thruster with different gas compositions is studied experimentally, which is obtained by measuring the radio frequency power and current of the antenna coil with and without discharge operation. The results show that increasing the turns of antenna coils can effectively improve the radio frequency power transfer efficiency, which is due to the improvement of Q factor. In pure N_2 discharge,with the increase of radio frequency power, the radio frequency power transfer efficiency first rises rapidly and then exhibits a less steep increasing trend. The radio frequency power transfer efficiency increases with the increase of gas pressure at relatively high power, while declines rapidly at relatively low power. In N_(2)/O_(2) discharge, increasing the N_(2) content at high power can improve the radio frequency power transfer efficiency, but the opposite was observed at low power. In order to give a better understanding of these trends, an analytic solution in limit cases is utilized, and a Langmuir probe was employed to measure the electron density. It is found that the evolution of radio frequency power transfer efficiency can be well explained by the variation of plasma resistance, which is related to the electron density and the effective electron collision frequency.

关键词： radio frequency ion thruster inductively coupled plasma power transfer efficiency analytic solution

Hot Compression Behavior and Tensile Property of a Novel Ni-Co-Based Superalloy Prepared by Electron Beam Smelting Layered Solidification Technology

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Acta Metallurgica Sinica(English Letters) 2024年第2期37卷 283-292页

作者： Yong-Chao Gai Rui Zhang Chuan-Yong Cui Zi-Jian Zhou Yi Tan Yi-Zhou Zhou Xiao-Feng Sun Key laboratory of materials modification by Laser Ionand Electron Beams(Ministry of Education)School of Materials Science and EngineeringDalian University of TechnologyDalian116024China Shi-Changxu Innovation Center for Advanced materials Institute of Metal ResearchChinese Academy of SciencesShenyang110016China

The hot compression behavior and tensile strength after compression of a new Ni-Co-based superalloy produced using electron beam smelting layered(EBSL)solidification technology were *** compression tests were performed at temperatures of 1120℃and 1150℃,with strain rates of 1 s^(-1) and 0.01 s^(-1),reaching a true strain of *** strength was evaluated at room *** results revealed that this EBSL technology accelerates dynamic recrystallization(DRX),without compromising the strength of alloy.A significant correlation between the volume fraction of DRX and the strain rate was observed,with higher fractions at lower strain rates,leading to higher tensile ***,at the same strain rate,the specimens compressed at 1120℃exhibited higher tensile strength due to undissolvedγ′*** solution and aging heat treatment,the alloy maintained high tensile *** results suggested that the EBSL Ni-Co-based superalloy offers excellent prospects for practical applications.

关键词： Ni-Co-based superalloy Hot deformation Electron beam smelting Tensile strength

Effects of diamagnetic drift on nonlinear interaction between multi-helicity neoclassical tearing modes

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Chinese Physics B 2024年第6期33卷 452-458页

作者：王海源姜帅刘桐魏来栾其斌王正汹 Key laboratory of materials modification by Laser Ionand Electron Beams of the Ministry of EducationSchool of PhysicsDalian University of TechnologyDalian 116024China Faculty of Electronic Information and Electrical Engineering Dalian University of TechnologyDalian 116024China

A numerical study of the diamagnetic drift effect on the nonlinear interaction between multi-helicity neoclassical tearing modes(NTMs) is carried out using a set of four-field equations including two-fluid *** results show that,in contrast to the single-fluid case,5/3 NTM cannot be completely suppressed by 3/2 NTM with diamagnetic drift *** modes exhibit oscillation and coexist in the saturated *** better understand the effect of the diamagnetic drift flow on multiple-helicity NTMs,the influence of typical relevant parameters is *** is found that the average saturated magnetic island width increases with increasing bootstrap current fraction f_(b) but decreases with the ion skin depth δ.In addition,as the ratio of parallel to perpendicular transport coefficients χ_(‖)/χ_(⊥) increases,the average saturated magnetic island widths of the 3/2 and 5/3 NTMs *** underlying mechanisms behind these observations are discussed in detail.

关键词： tokamak two-fluid neoclassical tearing modes multi-helicity

Defect-modulated synthesis and optoelectronic properties in chemical vapor deposited CsPbBr_(3) microplates

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Nano Research 2024年第5期17卷 4610-4615页

作者： Yanan Bao Hengshan Wang Meiqi An Huayi Tang Jing Li Jianliang Li Conghui Tan Yingmin Luo Jiao Xu Yiming Yang School of Microelectronics Dalian University of TechnologyDalian 116024China Key laboratory of materials modification by Laser Ionand Electron Beams(Ministry of Education)School of PhysicsDalian University of TechnologyDalian 116024China

The remarkable optoelectronic features of halide perovskite promote their potential applications in semiconductor devices beyond solar cells,which require high-quality single crystals with controlled defect ***,we investigated the synthesis mechanism of chemical vapor deposited single-crystalline all-inorganic perovskite microplates(MPs),and reported a defect-modulated photocurrent which is closely related to the growth sequence of the *** MP synthesis initiates from island-like nano-disks,and subsequently transits to a layer-by-layer fashion,resulting in a defect-rich area at the center of the *** elevated temperatures,these central defects may be thermally activated and become highly mobile,leading to photoluminescence quenching and degression of local and overall optoelectronic attributes,as evidenced by the spatial resolved optical and electrical scanning probe ***,this work shines light on the formation,proliferation and dynamics of defects in perovskites,and offers guidance for preparation of high-quality perovskites micro-crystals for functional semiconductor devices with high temperature stability.

关键词： halide perovskites nanomaterials optoelectronics scanning photocurrent microscope chemical vapor deposition

Effect of high-energy Ne ions irradiation on mechanical properties difference between Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5)metallic glass and crystalline W

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Plasma Science and Technology 2024年第6期26卷 14-21页

作者：李娜张立松张小楠宫丽悦羌建兵梅显秀 Key laboratory of materials modification by Laser Ion and Electron BeamsMinistry of EducationDalian University of TechnologyDalian 116024People’s Republic of China School of Science Dalian Jiaotong UniversityDalian 116028People’s Republic of China

In this paper,high-energy Ne ions were used to irradiate Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) metallic glass(MG)and crystalline W to investigate their difference in mechanical response after *** results showed that with the irradiation dose increased,the tensile micro-strain increased,nano-hardness increased from 7.11 GPa to 7.90 GPa and 8.62 GPa,Young’s modulus increased,and H3/E2 increased which indicating that the plastic deformability decreased in crystalline *** the same irradiation conditions,the Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG still maintained the amorphous structure and became more disordered despite the longer range and stronger displacement damage of Ne ions in Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG than in crystalline *** the irradiation hardening and embrittlement behavior of crystalline W,Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG showed the gradual decrease in hardness from 6.02 GPa to 5.89 GPa and 5.50 GPa,the decrease in modulus and the increase in plastic deformability with the increasing ***,the irradiation softening and toughening phenomenon of Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG could provide new ideas for the design of nuclear materials.

关键词： heavy ions irradiation displacement damage metallic glass crystalline W mechanical property

Bilayer borophene:an efficient catalyst for hydrogen evolution reaction

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Frontiers of Chemical Science and Engineering 2024年第3期18卷 13-23页

作者： Na Xing Nan Gao Panbin Ye Xiaowei Yang Haifeng Wang Jijun Zhao College of Sciences/Xinjiang Production&Construction Corps Key laboratory of Advanced Energy Storage materials and Technologies Shihezi UniversityShihezi832000China Key laboratory of materials modification by Laser Ion and Electron Beams(Ministry of Education)Dalian University of TechnologyDalian116024China School of materials Science and Engineering Taizhou UniversityTaizhou318000China

The electrocatalytic hydrogen evolution reaction is a crucial technique for green hydrogen ***,finding affordable,stable,and efficient catalyst materials to replace noble metal catalysts remains a significant *** experimental breakthroughs in the synthesis of two-dimensional bilayer borophene provide a theoretical framework for exploring their physical and chemical *** this study,we systematically considered nine types of bilayer borophenes as potential electrocatalysts for the hydrogen evolution *** first-principles calculations revealed that bilayer borophenes exhibit high stability and excellent conductivity,possessing a relatively large specific surface area with abundant active *** surface boron atoms and the bridge sites between two boron atoms can serve as active sites,displaying high activity for the hydrogen evolution ***,the Gibbs free energy change associated with adsorption for these bilayer borophenes can reach as low as−0.002 eV,and the Tafel reaction energy barriers are lower(0.70 eV)than those on ***,the hydrogen evolution reaction activity of these two-dimensional bilayer borophenes can be described by engineering their work ***,we considered the effect of pH on hydrogen evolution reaction activity,with significant activity observed in an acidic *** theoretical results reveal the excellent catalytic performance of two-dimensional bilayer borophenes and provide crucial guidance for the experimental exploration of multilayer boron for various energy applications.

关键词： bilayer borophene hydrogen evolution reaction work function pH effect

Microstructural Evolutions and Mechanical Properties of Energetic Al_(1) (TiZrNbTaMoCr)_(15) High-Entropy Alloys

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Acta Metallurgica Sinica(English Letters) 2024年第4期37卷 620-632页

作者： Xuan-Hong Cai Zhen-Hua Wang Ben Niu Jin-Feng Li Qing Wang Show authors Key laboratory of materials modification By Laser Ion and Electron Beams(Ministry of Education)Engineering Research Center of High Entropy Alloy Materials(Liaoning Province)School of Materials Science and EngineeringDalian University of TechnologyDalian116024China Institute of materials China Academy of Engineering PhysicsMianyang621908China

The present study focuses on investigating the microstructural evolutions and mechanical properties of energetic Al_(1)(TiZrNbTaMoCr)_(15) refractory high-entropy alloys with the different heat treatments at low Al content state. It is found that even with a reduction in the Al content, the strength of these alloys remains unaffected at room temperature and high temperature, while the plasticity improves significantly. In particular, the coherent BCC/B_(2) microstructure with needle-like B_(2) nanoprecipitates dispersed into the BCC matrix is formed in 873 K-aged Al_(1)Ti_(6)Zr_(2)Nb_(3)Ta_(3)Mo_(0.5)Cr_(0.5) alloy. Therefore, this alloy exhibits the highest compression yield strength (σ_(YS) = 1333 and 717 MPa) at room temperature and 1073 K, respectively. After 973 K-aged, the coherent BCC/B_(2) microstructure underwent destabilization, and the B_(2) phase transforms into the brittle Zr5Al3 phase which then coarsens and dominates the microstructure of S3-AlTa_(3) alloy after 1073 K-aged. Moreover, these current alloys exhibit exceptionally high theoretical exothermic enthalpy (ΔH), surpassing 11606 J·g^(−1), which highlights their significant potential as innovative high-performance energetic structural materials.

关键词： Refractory high-entropy alloy Coherent microstructure Mechanical property Exothermic enthalpy

Effect of a negative DC bias on a capacitively coupled Ar plasma operated at different radiofrequency voltages and gas pressures

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Plasma Science and Technology 2024年第5期26卷 62-71页

作者：相垚君王晓坤刘永新王友年 Key laboratory of materials modification by Laser Ionand Electron Beams(Ministry of Education)School of PhysicsDalian University of TechnologyDalian 116024People’s Republic of China Chair of Applied Electrodynamics and Plasma Technology Ruhr University BochumBochum 44801Germany

The effect of a negative DC bias,|V_(dc)|,on the electrical parameters and discharge mode is investigated experimentally in a radiofrequency(RF)capacitively coupled Ar plasma operated at different RF voltage amplitudes and gas *** electron density is measured using a hairpin probe and the spatio-temporal distribution of the electron-impact excitation rate is determined by phase-resolved optical emission *** electrical parameters are obtained based on the waveforms of the electrode voltage and plasma current measured by a voltage probe and a current *** was found that at a low|V_(dc)|,***α-mode,the electron density and RF current decline with increasing|V_(dc)|;meanwhile,the plasma impedance becomes more capacitive due to a widened ***,RF power deposition is ***|V_(dc)|exceeds a certain value,the plasma changes toα–γhybrid mode(or the discharge becomes dominated by theγ-mode),manifesting a drastically growing electron density and a moderately increasing RF ***,the plasma impedance becomes more resistive,so RF power deposition is enhanced with|V_(dc)|.We also found that the electrical parameters show similar dependence on|V_(dc)|at different RF voltages,andα–γmode transition occurs at a lower|V_(dc)|at a higher RF *** increasing the pressure,plasma impedance becomes more resistive,so RF power deposition and electron density are *** particular,theα–γmode transition tends to occur at a lower|V_(dc)|with increase in pressure.

关键词： RF capacitively coupled plasma DC-overlapped RF discharge power deposition discharge mode transition

Structure-preserving algorithms for guiding center dynamics based on the slow manifold of classical Pauli particle

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Plasma Science and Technology 2024年第6期26卷 88-102页

作者：张若涵王正汹肖建元王丰 Key laboratory of materials modification by Laser Ion and Electron BeamsSchool of PhysicsDalian University of TechnologyDalian 116024People’s Republic of China Department of Plasma Physics and Fusion Engineering University of Science and Technology of ChinaHefei 230026People’s Republic of China

The classical Pauli particle(CPP) serves as a slow manifold, substituting the conventional guiding center dynamics. Based on the CPP, we utilize the averaged vector field(AVF) method in the computations of drift orbits. Demonstrating significantly higher efficiency, this advanced method is capable of accomplishing the simulation in less than one-third of the time of directly computing the guiding center motion. In contrast to the CPP-based Boris algorithm, this approach inherits the advantages of the AVF method, yielding stable trajectories even achieved with a tenfold time step and reducing the energy error by two orders of magnitude. By comparing these two CPP algorithms with the traditional RK4 method, the numerical results indicate a remarkable performance in terms of both the computational efficiency and error elimination. Moreover, we verify the properties of slow manifold integrators and successfully observe the bounce on both sides of the limiting slow manifold with deliberately chosen perturbed initial conditions. To evaluate the practical value of the methods, we conduct simulations in non-axisymmetric perturbation magnetic fields as part of the experiments,demonstrating that our CPP-based AVF method can handle simulations under complex magnetic field configurations with high accuracy, which the CPP-based Boris algorithm lacks. Through numerical experiments, we demonstrate that the CPP can replace guiding center dynamics in using energy-preserving algorithms for computations, providing a new, efficient, as well as stable approach for applying structure-preserving algorithms in plasma simulations.

关键词： structure-preserving algorithm averaged vector field classical Pauli particle guiding center dynamics