A fast-sweep Langmuir probe （FSLP） diagnostic system was designed and applied to obtain the electron temperature fluctuations of a transient plasma. The diagnostic system consists of a single Langmuir probe driven b...A fast-sweep Langmuir probe （FSLP） diagnostic system was designed and applied to obtain the electron temperature fluctuations of a transient plasma. The diagnostic system consists of a single Langmuir probe driven by a high frequency sinusoidal voltage. The current-voltage I- V characteristics can be recorded by sweeping the voltage and measuring the current with an appropriate circuit. This new instrument is based on a dual channel circuit that compensates for stray capacitance. The current and voltage spectra were acquired from the probe synchronously by a digital oscilloscope. The aim of this work was to apply the FSLP diagnostic system to a time- dependent plasma generated by a hypervelocity impact between the LY12 Aluminum projectile and LY12 Aluminum target.展开更多
Coupled with hot-continuous rolling technology and based on the calculation of the finishing rolling impact work in the non-quenched and tempered Si-Mn steel, the calculations of the finishing rolling impact work in t...Coupled with hot-continuous rolling technology and based on the calculation of the finishing rolling impact work in the non-quenched and tempered Si-Mn steel, the calculations of the finishing rolling impact work in the alloying non-quenched and tempered steel with the elements of Cr, Ni, Mo, W, Cu, V, Nb and Ti are studied with the covalent electron number nA of the strongest bond in alloying phases, the smallest electron density difference ?ρ of phase interfaces, and the number of atom states σ (σ′) which keep the interface electron density continuous. The calculated results show that the finishing rolling impact work of the alloying non-quenched and tempered steel intensely depends on strengthening mechanisms. The solution strengthening, interface strengthening, precipita- tion strengthening of pearlite, and dispersion strengthening will result in the decrease of the finishing rolling impact work; the refinement strengthening, the precipitation strength- ening of V, Nb and Ti in α-Fe-C-V(Nb, Ti), and the residual austenite containing Ni on the boundary of α-Fe-C-Ni will increase the impact work; and the increments or decrements can be calculated with nA, ?ρ, σ (σ′) and weights of alloying elements. The calculation formulas of the finishing rolling impact work in this paper are intergraded with the sug- gested ones of the finishing rolling tensile strength, yield strength, and elongation of the non-quenched and tempered steel. The calculated results agree well with the measured ones.展开更多
从电子传递机制、微生物活动和影响因子等角度出发,综述铁对厌氧氨氧化过程的影响。结果表明,不同价态的铁作为电子受体或电子供体生成厌氧氨氧化底物促进反应,且产生铁氨氧化(Feammox)、硝酸盐依赖型亚铁氧化反应(nitrate-dependent fe...从电子传递机制、微生物活动和影响因子等角度出发,综述铁对厌氧氨氧化过程的影响。结果表明,不同价态的铁作为电子受体或电子供体生成厌氧氨氧化底物促进反应,且产生铁氨氧化(Feammox)、硝酸盐依赖型亚铁氧化反应(nitrate-dependent ferrous iron oxidation,NAFO)等不同反应。同时铁元素对厌氧氨氧化过程中功能微生物富集、血红素含量提升及颗粒化过程均有促进作用,从而明显提升对厌氧氨氧化工艺的处理效果。并总结了最佳的铁投加状态,铁元素加强厌氧氨氧化过程中的最适温度、pH值,为后续的铁元素加强厌氧氨氧化过程的研究提供参考。展开更多
The electron-impact single ionization cross section for W8+ion has been calculated using flexible atomic code,employing the level-to-level distorted-wave approximation.This calculations takes into account contribution...The electron-impact single ionization cross section for W8+ion has been calculated using flexible atomic code,employing the level-to-level distorted-wave approximation.This calculations takes into account contributions form both direct ionization(DI)and excitation autoionization(EA).However,the theoretical predictions,based solely on the ground state,tends to underestimate the experimental values.This discrepancy can be mitigated by incorporation contributions from excited states.We extended the theoretical analysis,including the contributions from the long-lived metastable states with lifetimes exceeding 1.5×10-5 s.We employed two statistical models to predict the fraction of ground state ions in the parent ion beam.Assuming a 79%fraction of parent ions in ground configuration,the experiment measurements align with the predictions.Furthermore we derived the theoretical cross-section for the ground state as correlated plasma rate coefficients,and compared it with existing data.Despite the uncertainty in our calculations,our results are still acceptable.展开更多
The absolute partial and total cross sections for electron impact ionization of carbon monoxide are reported for electron energies from 350 eV to 8000 eV.The product ions(CO^(+),C^(+),O^(+),CO^(2+),C^(2+),and O^(2+))a...The absolute partial and total cross sections for electron impact ionization of carbon monoxide are reported for electron energies from 350 eV to 8000 eV.The product ions(CO^(+),C^(+),O^(+),CO^(2+),C^(2+),and O^(2+))are measured by employing an ion imaging mass spectrometer and two ion-pair dissociation channels(C^(+)+O^(+)and C^(2+)+O^(+))are identified.The absolute cross sections for producing individual ions and their total,as well as for the ion-pair dissociation channels are obtained by normalizing the data of CO^(+)to that of Ar^(+)from CO-Ar mixture target with a fixed 1:1 ratio.The overall errors are evaluated by considering various kinds of uncertainties.A comprehensive comparison is made with the available data,which shows a good agreement with each other over the energy ranges that are overlapped.This work presents new cross-section data with electron energies above 1000 eV.展开更多
In recent years,exploring the relationship between community structure and node centrality in complex networks has gained significant attention from researchers,given its fundamental theoretical significance and pract...In recent years,exploring the relationship between community structure and node centrality in complex networks has gained significant attention from researchers,given its fundamental theoretical significance and practical implications.To address the impact of network communities on target nodes and effectively identify highly influential nodes with strong propagation capabilities,this paper proposes a novel influential spreaders identification algorithm based on density entropy and community structure(DECS).The proposed method initially integrates a community detection algorithm to obtain the community partition results of the networks.It then comprehensively considers the internal and external density entropies and degree centrality of the target node to evaluate its influence.Experimental validation is conducted on eight networks of varying sizes through susceptible–infected–recovered(SIR)propagation experiments and network static attack experiments.The experimental results demonstrate that the proposed method outperforms five other node centrality methods under the same comparative conditions,particularly in terms of information spreading capability,thereby enhancing the accurate identification of critical nodes in networks.展开更多
The electron impact excitation(EIE) cross sections of an atom/ion in the whole energy region are needed in many research fields, such as astrophysics studies, inertial confinement fusion researches and so on. In the p...The electron impact excitation(EIE) cross sections of an atom/ion in the whole energy region are needed in many research fields, such as astrophysics studies, inertial confinement fusion researches and so on. In the present work, an effective method to calculate the EIE cross sections of an atom/ion in the whole energy region is presented. We use the EIE cross sections of helium as an illustration example. The optical forbidden 1^(1)S–n^(1)S(n = 2–4) and optical allowed 1^(1)S–n^(1)P(n = 2–4) excitation cross sections are calculated in the whole energy region using the scheme that combines the partial wave R-matrix method and the first Born approximation. The calculated cross sections are in good agreement with the available experimental measurements. Based on these accurate cross sections of our calculation, we find that the ratios between the accurate cross sections and Born cross sections are nearly the same for different excitation final states in the same channel. According to this interesting property, a universal correction function is proposed and given to calculate the accurate EIE cross sections with the same computational efforts of the widely used Born cross sections,which should be very useful in the related application fields. The datasets presented in this paper are openly available at https://www.doi.org/10.57760/sciencedb.j00113.00142.展开更多
Spectral line widths produced by collisions between charged particles and emitters are of special interest for precise plasma spectroscopy.The highly charged Ar XV ion is demonstrated to have strong intrashell electro...Spectral line widths produced by collisions between charged particles and emitters are of special interest for precise plasma spectroscopy.The highly charged Ar XV ion is demonstrated to have strong intrashell electron interactions,which manifest as an atomic system with many resonance structures,due to the quasi-degeneracy of orbital energies.In this paper we use the relativistic R-matrix method to investigate the electron-impact broadening of highly charged Ar XV ion spectral lines under the impact approximation.It is found that the results considering resonance structures are significantly different from those of the distorted wave approach.Furthermore,we propose a new empirical formula with a correction term to take into account the effect of resonances for electron-impact widths over a relatively wide range of plasma conditions.The corresponding fitting parameters of the new empirical formula for all 47 calculated transitions are also given with an estimated accuracy within 1%,which should be convenient for practical applications.The dataset that supported the findings of this study is available in Science Data Bank,with the link https://doi.org/10.57760/sciencedb.j00113.00101.展开更多
Electron-impact single-ionization(EISI)cross sections for W^(q+)(q=9,10)ions have been calculated by using the level-to-level distorted-wave(LLDW)method with emphasis on the contribution of metastable states to the to...Electron-impact single-ionization(EISI)cross sections for W^(q+)(q=9,10)ions have been calculated by using the level-to-level distorted-wave(LLDW)method with emphasis on the contribution of metastable states to the total ionization cross sections.Contributions from direct-ionization(DI)and excitation-autoionization(EA)processes are taken into account.The calculated cross sections include the contributions from both the ground configuration and the long-lived metastable states with lifetimes exceeding 10^(-6)s.Calculated cross sections are in good agreement with experimental measurements when the influence of metastable states on the total ionization cross section are well considered.展开更多
Two techniques are applied to diagnose characteristic parameters of plasma created by hypervelocity impact, such as electron temperature and electron density. The first technique is a sweep Langmuir probe （SLP）, whi...Two techniques are applied to diagnose characteristic parameters of plasma created by hypervelocity impact, such as electron temperature and electron density. The first technique is a sweep Langmuir probe （SLP）, which is a new apparatus based on a dual channel circuit that can compensate for stray capacitance and obtain a good synchronicity, so that electrostatic turbulence with a good temporal resolution can be acquired. The second technique is a triple Langmuir probe （TLP）, which is an electrostatic triple Langmuir probe diagnostic system, in which no voltage and frequency sweep is required. This technique allows to measure electron temperature, electron density as a function of time. Moreover, the triple Langmuir probe diagnostic system allows the direct display of electron temperature and semidirect display of electron density by an appropriate display system, the system permits us to eliminate almost all data processing procedures. SLP and TLP were applied to obtain fluctuations of the characteristic parameters of plasma generated by hypervelocity impact. As an example of their application to time-dependent plasma measure- ment, the electron temperature and electron density of plasmas were acquired in hypervelocity impact experiments. Characteristic parameters of plasma generated by hypervelocity impact were compared by the two kinds of diagnostic techniques mentioned above.展开更多
Cross sections of electron-loss in H（1s）＋ H（1s） collisions and total collisional destruction of H（2s） in H（1s） 4- H（2s） collisions are calculatted by four-body classical-trajectory Monte Caylo （CTMC） meth...Cross sections of electron-loss in H（1s）＋ H（1s） collisions and total collisional destruction of H（2s） in H（1s） 4- H（2s） collisions are calculatted by four-body classical-trajectory Monte Caylo （CTMC） method and compared with previous theoretical and experimental data over the energy range of 4-100 keV. For the former a good agreement is obtained within different four-body CTMC calculations, and for the incident energy Ep 〉 10 keV, comparison with the experimental data shows a better agreement than the results calculated by the impact parameter approx- imation. For the latter, our theory predicts the correct experimental behaviour, and the discrepancies between our results and experimental ones are less than 30%. Based on the successive comparison with experiments, the cross sections for excitation to H（2p）, single- and double-ionization and H- formation in H（2s）＋H（2s） collisions are calculated in the energy range of 4-100 keV for the first time, and compared with those in H（1s）＋H（1s） and H（1s）＋U（2s） collisions.展开更多
基金National Natural Science Foundation of China(No.10772028)
文摘A fast-sweep Langmuir probe （FSLP） diagnostic system was designed and applied to obtain the electron temperature fluctuations of a transient plasma. The diagnostic system consists of a single Langmuir probe driven by a high frequency sinusoidal voltage. The current-voltage I- V characteristics can be recorded by sweeping the voltage and measuring the current with an appropriate circuit. This new instrument is based on a dual channel circuit that compensates for stray capacitance. The current and voltage spectra were acquired from the probe synchronously by a digital oscilloscope. The aim of this work was to apply the FSLP diagnostic system to a time- dependent plasma generated by a hypervelocity impact between the LY12 Aluminum projectile and LY12 Aluminum target.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 50471022).
文摘Coupled with hot-continuous rolling technology and based on the calculation of the finishing rolling impact work in the non-quenched and tempered Si-Mn steel, the calculations of the finishing rolling impact work in the alloying non-quenched and tempered steel with the elements of Cr, Ni, Mo, W, Cu, V, Nb and Ti are studied with the covalent electron number nA of the strongest bond in alloying phases, the smallest electron density difference ?ρ of phase interfaces, and the number of atom states σ (σ′) which keep the interface electron density continuous. The calculated results show that the finishing rolling impact work of the alloying non-quenched and tempered steel intensely depends on strengthening mechanisms. The solution strengthening, interface strengthening, precipita- tion strengthening of pearlite, and dispersion strengthening will result in the decrease of the finishing rolling impact work; the refinement strengthening, the precipitation strength- ening of V, Nb and Ti in α-Fe-C-V(Nb, Ti), and the residual austenite containing Ni on the boundary of α-Fe-C-Ni will increase the impact work; and the increments or decrements can be calculated with nA, ?ρ, σ (σ′) and weights of alloying elements. The calculation formulas of the finishing rolling impact work in this paper are intergraded with the sug- gested ones of the finishing rolling tensile strength, yield strength, and elongation of the non-quenched and tempered steel. The calculated results agree well with the measured ones.
基金financially supported by the National Natural Science Foundation of China(No.51365014)the Industrial Support Key Project of Jiangxi Province,China(No.20161BBE50072)
文摘从电子传递机制、微生物活动和影响因子等角度出发,综述铁对厌氧氨氧化过程的影响。结果表明,不同价态的铁作为电子受体或电子供体生成厌氧氨氧化底物促进反应,且产生铁氨氧化(Feammox)、硝酸盐依赖型亚铁氧化反应(nitrate-dependent ferrous iron oxidation,NAFO)等不同反应。同时铁元素对厌氧氨氧化过程中功能微生物富集、血红素含量提升及颗粒化过程均有促进作用,从而明显提升对厌氧氨氧化工艺的处理效果。并总结了最佳的铁投加状态,铁元素加强厌氧氨氧化过程中的最适温度、pH值,为后续的铁元素加强厌氧氨氧化过程的研究提供参考。
基金Project supported by the National Natural Science Foundation of China(Grant No.12364034)the National Key Research and Development Program of China(Grant No.2022YFA1602501)the Science and Technology Project of Gansu Province,China(Grant No.23YFFA0074).
文摘The electron-impact single ionization cross section for W8+ion has been calculated using flexible atomic code,employing the level-to-level distorted-wave approximation.This calculations takes into account contributions form both direct ionization(DI)and excitation autoionization(EA).However,the theoretical predictions,based solely on the ground state,tends to underestimate the experimental values.This discrepancy can be mitigated by incorporation contributions from excited states.We extended the theoretical analysis,including the contributions from the long-lived metastable states with lifetimes exceeding 1.5×10-5 s.We employed two statistical models to predict the fraction of ground state ions in the parent ion beam.Assuming a 79%fraction of parent ions in ground configuration,the experiment measurements align with the predictions.Furthermore we derived the theoretical cross-section for the ground state as correlated plasma rate coefficients,and compared it with existing data.Despite the uncertainty in our calculations,our results are still acceptable.
基金Project supported by the National Key Research and Development Program of China (Grant No.2022YFA1602502)the National Natural Science Foundation of China (Grant No.12127804)the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant Nos.XDB34000000)。
文摘The absolute partial and total cross sections for electron impact ionization of carbon monoxide are reported for electron energies from 350 eV to 8000 eV.The product ions(CO^(+),C^(+),O^(+),CO^(2+),C^(2+),and O^(2+))are measured by employing an ion imaging mass spectrometer and two ion-pair dissociation channels(C^(+)+O^(+)and C^(2+)+O^(+))are identified.The absolute cross sections for producing individual ions and their total,as well as for the ion-pair dissociation channels are obtained by normalizing the data of CO^(+)to that of Ar^(+)from CO-Ar mixture target with a fixed 1:1 ratio.The overall errors are evaluated by considering various kinds of uncertainties.A comprehensive comparison is made with the available data,which shows a good agreement with each other over the energy ranges that are overlapped.This work presents new cross-section data with electron energies above 1000 eV.
基金Project supported by the National Natural Science Foundation of China(Grant No.61803264)。
文摘In recent years,exploring the relationship between community structure and node centrality in complex networks has gained significant attention from researchers,given its fundamental theoretical significance and practical implications.To address the impact of network communities on target nodes and effectively identify highly influential nodes with strong propagation capabilities,this paper proposes a novel influential spreaders identification algorithm based on density entropy and community structure(DECS).The proposed method initially integrates a community detection algorithm to obtain the community partition results of the networks.It then comprehensively considers the internal and external density entropies and degree centrality of the target node to evaluate its influence.Experimental validation is conducted on eight networks of varying sizes through susceptible–infected–recovered(SIR)propagation experiments and network static attack experiments.The experimental results demonstrate that the proposed method outperforms five other node centrality methods under the same comparative conditions,particularly in terms of information spreading capability,thereby enhancing the accurate identification of critical nodes in networks.
基金Project supported by the National Natural Science Foundation of China (Grant No. 12241410)。
文摘The electron impact excitation(EIE) cross sections of an atom/ion in the whole energy region are needed in many research fields, such as astrophysics studies, inertial confinement fusion researches and so on. In the present work, an effective method to calculate the EIE cross sections of an atom/ion in the whole energy region is presented. We use the EIE cross sections of helium as an illustration example. The optical forbidden 1^(1)S–n^(1)S(n = 2–4) and optical allowed 1^(1)S–n^(1)P(n = 2–4) excitation cross sections are calculated in the whole energy region using the scheme that combines the partial wave R-matrix method and the first Born approximation. The calculated cross sections are in good agreement with the available experimental measurements. Based on these accurate cross sections of our calculation, we find that the ratios between the accurate cross sections and Born cross sections are nearly the same for different excitation final states in the same channel. According to this interesting property, a universal correction function is proposed and given to calculate the accurate EIE cross sections with the same computational efforts of the widely used Born cross sections,which should be very useful in the related application fields. The datasets presented in this paper are openly available at https://www.doi.org/10.57760/sciencedb.j00113.00142.
基金the National Natural Science Foundation of China(Grant Nos.11934004,U1832201,and 12241410)the Science Challenge Project(Grant No.TZ2016005)+1 种基金the CAEP Foundation(Grant No.CX2019022)the Special Innovation Project for National Defense。
文摘Spectral line widths produced by collisions between charged particles and emitters are of special interest for precise plasma spectroscopy.The highly charged Ar XV ion is demonstrated to have strong intrashell electron interactions,which manifest as an atomic system with many resonance structures,due to the quasi-degeneracy of orbital energies.In this paper we use the relativistic R-matrix method to investigate the electron-impact broadening of highly charged Ar XV ion spectral lines under the impact approximation.It is found that the results considering resonance structures are significantly different from those of the distorted wave approach.Furthermore,we propose a new empirical formula with a correction term to take into account the effect of resonances for electron-impact widths over a relatively wide range of plasma conditions.The corresponding fitting parameters of the new empirical formula for all 47 calculated transitions are also given with an estimated accuracy within 1%,which should be convenient for practical applications.The dataset that supported the findings of this study is available in Science Data Bank,with the link https://doi.org/10.57760/sciencedb.j00113.00101.
基金Project supported by the National Natural Science Foundation of China(Grant No.11404152)Fundamental Research Funds for the Central Universities(Grant No.lzujbky2017-94)。
文摘Electron-impact single-ionization(EISI)cross sections for W^(q+)(q=9,10)ions have been calculated by using the level-to-level distorted-wave(LLDW)method with emphasis on the contribution of metastable states to the total ionization cross sections.Contributions from direct-ionization(DI)and excitation-autoionization(EA)processes are taken into account.The calculated cross sections include the contributions from both the ground configuration and the long-lived metastable states with lifetimes exceeding 10^(-6)s.Calculated cross sections are in good agreement with experimental measurements when the influence of metastable states on the total ionization cross section are well considered.
基金supported by National Natural Science Foundation of China(No.10972145)
文摘Two techniques are applied to diagnose characteristic parameters of plasma created by hypervelocity impact, such as electron temperature and electron density. The first technique is a sweep Langmuir probe （SLP）, which is a new apparatus based on a dual channel circuit that can compensate for stray capacitance and obtain a good synchronicity, so that electrostatic turbulence with a good temporal resolution can be acquired. The second technique is a triple Langmuir probe （TLP）, which is an electrostatic triple Langmuir probe diagnostic system, in which no voltage and frequency sweep is required. This technique allows to measure electron temperature, electron density as a function of time. Moreover, the triple Langmuir probe diagnostic system allows the direct display of electron temperature and semidirect display of electron density by an appropriate display system, the system permits us to eliminate almost all data processing procedures. SLP and TLP were applied to obtain fluctuations of the characteristic parameters of plasma generated by hypervelocity impact. As an example of their application to time-dependent plasma measure- ment, the electron temperature and electron density of plasmas were acquired in hypervelocity impact experiments. Characteristic parameters of plasma generated by hypervelocity impact were compared by the two kinds of diagnostic techniques mentioned above.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10434100, 10574018 and 10574020.
文摘Cross sections of electron-loss in H（1s）＋ H（1s） collisions and total collisional destruction of H（2s） in H（1s） 4- H（2s） collisions are calculatted by four-body classical-trajectory Monte Caylo （CTMC） method and compared with previous theoretical and experimental data over the energy range of 4-100 keV. For the former a good agreement is obtained within different four-body CTMC calculations, and for the incident energy Ep 〉 10 keV, comparison with the experimental data shows a better agreement than the results calculated by the impact parameter approx- imation. For the latter, our theory predicts the correct experimental behaviour, and the discrepancies between our results and experimental ones are less than 30%. Based on the successive comparison with experiments, the cross sections for excitation to H（2p）, single- and double-ionization and H- formation in H（2s）＋H（2s） collisions are calculated in the energy range of 4-100 keV for the first time, and compared with those in H（1s）＋H（1s） and H（1s）＋U（2s） collisions.
