The simulation calculation and analysis of electron transmittance and ion stopping power for ion barrier films (IBFs) of Al2O3 and SiO2 are performed by Monte Carlo methods. The interaction model between particles and...The simulation calculation and analysis of electron transmittance and ion stopping power for ion barrier films (IBFs) of Al2O3 and SiO2 are performed by Monte Carlo methods. The interaction model between particles and solids are described. It is found that at the same conditions,the electron transmittance for SiO2 IBF is relatively higher than that of Al2O3 IBF,and the ion stopping power of SiO2 IBF is relatively lower than that of Al2O3 by Monte Carlo simulations. It is also indicated that SiO2 is one of the ideal materials for fabricating IBFs.展开更多
Ion-implantation layers are fabricated by multiple nitrogen ion-implantations （3 times for sample A and 4 times for sample B） into a p-type 4H-SiC epitaxial layer. The implantation depth profiles are calculated by u...Ion-implantation layers are fabricated by multiple nitrogen ion-implantations （3 times for sample A and 4 times for sample B） into a p-type 4H-SiC epitaxial layer. The implantation depth profiles are calculated by using the Monte Carlo simulator TRIM. The fabrication process and the I-V and C V characteristics of the lateral Ti/4H-SiC Schottky barrier diodes （SBDs） fabricated on these multiple box-like ion-implantation layers are presented in detail. Measurements of the reverse I V characteristics demonstrate a low reverse current, which is good enough for many SiC-based devices such as SiC metal-semiconductor field-effect transistors （MESFETs）, and SiC static induction transistors （SITs）. The parameters of the diodes are extracted from the forward I-V and C-V characteristics. The values of ideality factor n of SBDs for samples A and B are 3.0 and 3.5 respectively, and the values of series resistance Rs are 11.9 and 1.0 kf~ respectively. The values of barrier height φB of Ti/4H-SiC are 0.95 and 0.72 eV obtained by the I-V method and 1.14 and 0.93 eV obtained by the C-V method for samples A and B respectively. The activation rates for the implanted nitrogen ions of samples A and B are 2% and 4% respectively extracted from C V testing results.展开更多
The kinetic energy of ions in dielectric barrier discharge plasmas are analysed theoretically using the model of binary collisions between ions and gas molecules. Langevin equation for ions in other gases, Blanc law f...The kinetic energy of ions in dielectric barrier discharge plasmas are analysed theoretically using the model of binary collisions between ions and gas molecules. Langevin equation for ions in other gases, Blanc law for ions in mixed gases, and the two-temperature model for ions at higher reduced field are used to determine the ion mobility. The kinetic energies of ions in CH4 ＋ Ar（He） dielectric barrier discharge plasma at a fixed total gas pressure and various Ar （He） concentrations are calculated. It is found that with increasing Ar （He） concentration in CH4 ＋ Ar （He） from 20% to 83%, the CH4＋ kinetic energy increases from 69.6 （43.9） to 92.1 （128.5）eV, while the Ar＋ （He＋） kinetic energy decreases from 97 （145.2） to 78.8 （75.5）eV. The increase of CH4＋ kinetic energy is responsible for the increase of hardness of diamond-like carbon films deposited by CH4 ＋ Ar （He） dielectric barrier discharge without bias voltage over substrates.展开更多
In order to undertake theory analysis in the application area of switching,frequency and power devices,an analytical model for capacitance-voltage (C-V) characteristics of ion-implanted 4H silicon carbide (SiC) Schott...In order to undertake theory analysis in the application area of switching,frequency and power devices,an analytical model for capacitance-voltage (C-V) characteristics of ion-implanted 4H silicon carbide (SiC) Schottky barrier diodes (SBDs) was investigated.This model was established by considering the effects of incomplete ionization of nitrogen in 4H-SiC,the Poole-Frenkel on the ionization energy,and the ion-implanted nitrogen donor profiles.The simulation process is discussed in detail for two multiple nitrogen ion-implanted 4H-SiC SBDs (three and four fold ion-implantations) designed and fabricated in the experiments using this model at different activation rates.An agreement between the modeled C-V curves and the measured results for two ion-implanted 4H-SiC SBDs fabricated is shown.This capacitance model has the potential to be used to simulate and design ion-implanted SiC devices concerned in the future.展开更多
Metal and acid ions contamination of soil in China is serious. To find an efficient solution for remediating the combined pollution,electrokinetics( EK) coupled with chitosan( CTS)permeable reactive barrier( EK/CPRB) ...Metal and acid ions contamination of soil in China is serious. To find an efficient solution for remediating the combined pollution,electrokinetics( EK) coupled with chitosan( CTS)permeable reactive barrier( EK/CPRB) was used to investigate the performances of metal and acid ions remediation. Adsorption characteristics of Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- onto CTS were also conducted. The results showed the sorption of Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- on CTS could be well described by Freundlich model. When the CTS dosage is 8 g,the total removal efficiency for Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- is 86. 8%,90. 2%,92. 4%,90. 0% and 82. 5%,respectively. CTS enhanced ions remediation efficiencies significantly compared with the single EK system,especially for SO_4^(2-) and NO_3^-. The results indicate EK/CPRB system is suitable for the remediation of soil contaminated by both metal ions and acid ions.展开更多
Ion temperature gradient (ITG) driven instability is studied withgyro-kinetic theory in an internal transport barrier (ITB) of tokamak plasmas. The stabilizationeffects of a parallel velocity shear on the modes are in...Ion temperature gradient (ITG) driven instability is studied withgyro-kinetic theory in an internal transport barrier (ITB) of tokamak plasmas. The stabilizationeffects of a parallel velocity shear on the modes are investigated. It is found that the modestructures and stability properties, as well as the effects of a velocity shear, in an ITB aresignificantly different from that in off-ITB regions.展开更多
The influence of surface barrier of solid upon ion reflection was studied in a few papers of other authors by using the Monte-Carlo simulation. Based on the bipartition model of ion transport, a new analytical theory ...The influence of surface barrier of solid upon ion reflection was studied in a few papers of other authors by using the Monte-Carlo simulation. Based on the bipartition model of ion transport, a new analytical theory has been developed instead of the MC simulation, due to important implication of the effect for fusion research. In the present paper we have calculated the number reflection coefficients of H+, D+, He and T+ normally incident on C,Al and Cu for ion energy from several eV to one hundred keV respectively. Our computational results accorded with the MC simulation. The results have shown that the effect of surface barrier on ion reflection becomes evident when the energy of incident ions is lower than one keV. In particular, for the ion energy from several eV to one hun dred eV, the discrepancies of number reflection coefficients can increase up to 0.1～0.3, showing this influence to be very important.展开更多
Charge transfer cross sections for Kr^q＋ with Ne are calculated quantitatively by using modified classical over barrier model in order to clarify energy dependence of charge transfer cross sections in low energy regi...Charge transfer cross sections for Kr^q＋ with Ne are calculated quantitatively by using modified classical over barrier model in order to clarify energy dependence of charge transfer cross sections in low energy region. Essential of this model is taking the induced dipole potential into consideration. As a result, this calculation can reproduce systematic energy dependence of experimental results. This suggests that the bending trajectory of the projectile due to an induced dipole potential should be considered to describe pictures of collisions at low energy regime below 1 keV/u.展开更多
In this study, dielectric barrier discharge plasma and ozone(O_3) were combined to synergistically degrade trans-ferulic acid(FA), and the effect of water quality on FA degradation was studied. The results showed that...In this study, dielectric barrier discharge plasma and ozone(O_3) were combined to synergistically degrade trans-ferulic acid(FA), and the effect of water quality on FA degradation was studied. The results showed that 96.9% of FA was degraded after 40 min treatment by the plasma/O_3 process. FA degradation efficiency increased with the p H values. The presence of suspended solid and humic acid inhibited FA degradation. FA degradation efficiency increased as the water temperature increased to 30 °C. However, the further increase in water temperature was adverse for FA degradation. Effects of common inorganic ions on FA degradation were also investigated. The addition of Cl^- inhibited the FA degradation, whileCO_3^(2-) had both negative and positive influences on FA degradation.NO_3^- andSO_4^(2-) did not have significant effect on FA degradation. Fe^(3+)and Cu^(2+)benefited FA degradation through the Fenton-like and catalytic ozonation reactions.展开更多
Sodium(Na)metal batteries with a high volumetric energy density that can be operated at high rates are highly desirable.However,an uneven Na-ion migration in bulk Na anodes leads to localized deposition/dissolution of...Sodium(Na)metal batteries with a high volumetric energy density that can be operated at high rates are highly desirable.However,an uneven Na-ion migration in bulk Na anodes leads to localized deposition/dissolution of sodium during high-rate plating/stripping behaviors,followed by severe dendrite growth and loose stacking.Herein,we engineer the Na hybrid anode with sodiophilic Na_(3)Bi-penetration to develop the abundant phase-boundary ionic transport channels.Compared to intrinsic Na,the reduced adsorption energy and ion-diffusion barrier on Na_(3)Bi ensure even Na^(+)nucleation and rapid Na^(+)migration within the hybrid electrode,leading to uniform deposition and dissolution at high current densities.Furthermore,the bismuthide enables compact Na deposition within the sodiophilic framework during cycling,thus favoring a high volumetric capacity.Consequently,the obtained anode was endowed with a high current density(up to 5 mA∙cm^(−2)),high areal capacity(up to 5 mA∙h∙cm^(−2)),and long-term cycling stability(up to 2800 h at 2 mA∙cm^(−2)).展开更多
From the theoretical analysis of the thermionic emission model of current-voltage characteristics, this paper extracts the parameters for the gate Schottky contact of two ion-implanted 4H-SiC metal-semiconductor field...From the theoretical analysis of the thermionic emission model of current-voltage characteristics, this paper extracts the parameters for the gate Schottky contact of two ion-implanted 4H-SiC metal-semiconductor field-effect transistors （sample A and sample B for three and four times multiple ion-implantation channel region respectively） fabricated in the experiment, including the ideality factor, the series resistance, the zero-field barrier height, the interface oxide capacitance, the interface state density distribution, the neutral level of interface states and the fixed space charge density. The methods to improve the interface of the ion-implanted Schottky contact are given at last.展开更多
This paper reports that the CoFe/IrMn bilayers are deposited by magnetron sputtering on the surfaces of thermallyoxidized Si substrates. It investigates the thermal relaxations of both non-irradiated and Ca^＋ ion irr...This paper reports that the CoFe/IrMn bilayers are deposited by magnetron sputtering on the surfaces of thermallyoxidized Si substrates. It investigates the thermal relaxations of both non-irradiated and Ca^＋ ion irradiated CoFe/IrMn bilayers by means of holding the bilayers in a negative saturation field. The results show that exchange bias field decreases with the increase of holding time period for both non-irradiated and Ca^＋ ion irradiated CoFe/IrMn bilayers. Exchange bias field is also found to be smaller upon irradiation at higher ion dose. This reduction of exchange bias field is attributed to the change of energy barrier induced by ion-radiation.展开更多
A spark generator was employed to assist surface barrier discharge （SBD） in nitrogen at atmospheric pressure. The influence of spark discharge on the SBD electrical behavior is investigated by means of volt-ampere c...A spark generator was employed to assist surface barrier discharge （SBD） in nitrogen at atmospheric pressure. The influence of spark discharge on the SBD electrical behavior is investigated by means of volt-ampere characteristics. Also, the electron density of plasma in the filament of each SBD arrangement is determined by plasma radiation method. It is found that the filaments in spark-assistant SBD are much stronger, while the corresponding mean electron density is much lower. Results show that the spark generator can improve the uniformity of SBD in atmospheric nitrogen in a particular range of applied frequency.展开更多
The degradation phenomena due to the energy pulse in the high-energy ZnO varistors used for deexitation and overvoltage protection of hydroelectric generator are investigated. The energy pulse, obtained by releasing t...The degradation phenomena due to the energy pulse in the high-energy ZnO varistors used for deexitation and overvoltage protection of hydroelectric generator are investigated. The energy pulse, obtained by releasing the energy stored in an inductor, can be equivalent to the combination of the DC field components and the energy component. The variations of the characterized voltages, nonlinear coefficients and pre-breakdown V-A characteristics, increase with the number of the applied energy pulse. The asymmetrical variations of the electric properties of the high-energy ZnO varistors after the energy pulse arise from the deformation of the double Schottky barriers due to the ion migration occuring in the depletion layer and in the grain boundary.展开更多
We investigate the single-electron loss processes of light charged ions （Li^1＋,2＋, C^2＋,3＋,5＋, and O^2＋,3＋） in collisions with helium. To better understand the experimental results, we propose a theoretical m...We investigate the single-electron loss processes of light charged ions （Li^1＋,2＋, C^2＋,3＋,5＋, and O^2＋,3＋） in collisions with helium. To better understand the experimental results, we propose a theoretical model to calculate the cross section of projectile electron loss. In this model, an ionization radius of the incident ion was defined under the classical over-barrier model, and we developed ＂strings＂ to explain the processes of projectile electron loss, which is similar with the molecular over-barrier model. Theoretical calculations are in good agreement with the experimental results for the cross section of single-electron loss and the ratio of double-to-single ionization of helium associated with one-electron loss.展开更多
The interaction potential for spherical-deformed reaction partners is calculated. The shape, separation and orientation dependence of the interaction potential and fusion cross section of the system ^32S＋^154Sm are i...The interaction potential for spherical-deformed reaction partners is calculated. The shape, separation and orientation dependence of the interaction potential and fusion cross section of the system ^32S＋^154Sm are investigated within the double-folding model of the deformed nuclei. The effective nucleon-nucleon interaction is taken to be the M3Y-Reid potential. The density is considered for three terms of the expansion using the truncated multipole expansion method, which is a deformed Fermi shape With quadrupole and hexadecapole for the density distribution of ^154Sm. It is found for the interaction potential that the height and the position of barrier strongly depend on the deformations, the orientation angle of the deformed nucleus, and hence produce great effects on fusion cross section. The integrated fusion cross section is in good agreement with the experimental data.展开更多
文摘The simulation calculation and analysis of electron transmittance and ion stopping power for ion barrier films (IBFs) of Al2O3 and SiO2 are performed by Monte Carlo methods. The interaction model between particles and solids are described. It is found that at the same conditions,the electron transmittance for SiO2 IBF is relatively higher than that of Al2O3 IBF,and the ion stopping power of SiO2 IBF is relatively lower than that of Al2O3 by Monte Carlo simulations. It is also indicated that SiO2 is one of the ideal materials for fabricating IBFs.
文摘Ion-implantation layers are fabricated by multiple nitrogen ion-implantations （3 times for sample A and 4 times for sample B） into a p-type 4H-SiC epitaxial layer. The implantation depth profiles are calculated by using the Monte Carlo simulator TRIM. The fabrication process and the I-V and C V characteristics of the lateral Ti/4H-SiC Schottky barrier diodes （SBDs） fabricated on these multiple box-like ion-implantation layers are presented in detail. Measurements of the reverse I V characteristics demonstrate a low reverse current, which is good enough for many SiC-based devices such as SiC metal-semiconductor field-effect transistors （MESFETs）, and SiC static induction transistors （SITs）. The parameters of the diodes are extracted from the forward I-V and C-V characteristics. The values of ideality factor n of SBDs for samples A and B are 3.0 and 3.5 respectively, and the values of series resistance Rs are 11.9 and 1.0 kf~ respectively. The values of barrier height φB of Ti/4H-SiC are 0.95 and 0.72 eV obtained by the I-V method and 1.14 and 0.93 eV obtained by the C-V method for samples A and B respectively. The activation rates for the implanted nitrogen ions of samples A and B are 2% and 4% respectively extracted from C V testing results.
基金Project supported by the National Natural Science Foundation of China （Grant No 10405005）.
文摘The kinetic energy of ions in dielectric barrier discharge plasmas are analysed theoretically using the model of binary collisions between ions and gas molecules. Langevin equation for ions in other gases, Blanc law for ions in mixed gases, and the two-temperature model for ions at higher reduced field are used to determine the ion mobility. The kinetic energies of ions in CH4 ＋ Ar（He） dielectric barrier discharge plasma at a fixed total gas pressure and various Ar （He） concentrations are calculated. It is found that with increasing Ar （He） concentration in CH4 ＋ Ar （He） from 20% to 83%, the CH4＋ kinetic energy increases from 69.6 （43.9） to 92.1 （128.5）eV, while the Ar＋ （He＋） kinetic energy decreases from 97 （145.2） to 78.8 （75.5）eV. The increase of CH4＋ kinetic energy is responsible for the increase of hardness of diamond-like carbon films deposited by CH4 ＋ Ar （He） dielectric barrier discharge without bias voltage over substrates.
文摘In order to undertake theory analysis in the application area of switching,frequency and power devices,an analytical model for capacitance-voltage (C-V) characteristics of ion-implanted 4H silicon carbide (SiC) Schottky barrier diodes (SBDs) was investigated.This model was established by considering the effects of incomplete ionization of nitrogen in 4H-SiC,the Poole-Frenkel on the ionization energy,and the ion-implanted nitrogen donor profiles.The simulation process is discussed in detail for two multiple nitrogen ion-implanted 4H-SiC SBDs (three and four fold ion-implantations) designed and fabricated in the experiments using this model at different activation rates.An agreement between the modeled C-V curves and the measured results for two ion-implanted 4H-SiC SBDs fabricated is shown.This capacitance model has the potential to be used to simulate and design ion-implanted SiC devices concerned in the future.
基金National Natural Science Foundations of China(Nos.21477018,21007010)the Fundamental Research Funds for the Central Universities,China(No.15D111323)+1 种基金Hunan Province Ministry of Transportation Scientific Research Projects,China(Nos.200908,201105)Ministry of Transport Science and Technology Program,China(No.2010353343290)
文摘Metal and acid ions contamination of soil in China is serious. To find an efficient solution for remediating the combined pollution,electrokinetics( EK) coupled with chitosan( CTS)permeable reactive barrier( EK/CPRB) was used to investigate the performances of metal and acid ions remediation. Adsorption characteristics of Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- onto CTS were also conducted. The results showed the sorption of Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- on CTS could be well described by Freundlich model. When the CTS dosage is 8 g,the total removal efficiency for Zn^(2+),Fe^(3+),Ca^(2+),SO_4^(2-) and NO_3^- is 86. 8%,90. 2%,92. 4%,90. 0% and 82. 5%,respectively. CTS enhanced ions remediation efficiencies significantly compared with the single EK system,especially for SO_4^(2-) and NO_3^-. The results indicate EK/CPRB system is suitable for the remediation of soil contaminated by both metal ions and acid ions.
基金The project supported by the National Nature Science Foundation of China (No.10135020)
文摘Ion temperature gradient (ITG) driven instability is studied withgyro-kinetic theory in an internal transport barrier (ITB) of tokamak plasmas. The stabilizationeffects of a parallel velocity shear on the modes are investigated. It is found that the modestructures and stability properties, as well as the effects of a velocity shear, in an ITB aresignificantly different from that in off-ITB regions.
基金Supported by the National Natural Science Foundation of China (No. 19375032) and International Atomic Energy Agency (Contract No. 8064/RB)
文摘The influence of surface barrier of solid upon ion reflection was studied in a few papers of other authors by using the Monte-Carlo simulation. Based on the bipartition model of ion transport, a new analytical theory has been developed instead of the MC simulation, due to important implication of the effect for fusion research. In the present paper we have calculated the number reflection coefficients of H+, D+, He and T+ normally incident on C,Al and Cu for ion energy from several eV to one hundred keV respectively. Our computational results accorded with the MC simulation. The results have shown that the effect of surface barrier on ion reflection becomes evident when the energy of incident ions is lower than one keV. In particular, for the ion energy from several eV to one hun dred eV, the discrepancies of number reflection coefficients can increase up to 0.1～0.3, showing this influence to be very important.
文摘Charge transfer cross sections for Kr^q＋ with Ne are calculated quantitatively by using modified classical over barrier model in order to clarify energy dependence of charge transfer cross sections in low energy region. Essential of this model is taking the induced dipole potential into consideration. As a result, this calculation can reproduce systematic energy dependence of experimental results. This suggests that the bending trajectory of the projectile due to an induced dipole potential should be considered to describe pictures of collisions at low energy regime below 1 keV/u.
文摘In this study, dielectric barrier discharge plasma and ozone(O_3) were combined to synergistically degrade trans-ferulic acid(FA), and the effect of water quality on FA degradation was studied. The results showed that 96.9% of FA was degraded after 40 min treatment by the plasma/O_3 process. FA degradation efficiency increased with the p H values. The presence of suspended solid and humic acid inhibited FA degradation. FA degradation efficiency increased as the water temperature increased to 30 °C. However, the further increase in water temperature was adverse for FA degradation. Effects of common inorganic ions on FA degradation were also investigated. The addition of Cl^- inhibited the FA degradation, whileCO_3^(2-) had both negative and positive influences on FA degradation.NO_3^- andSO_4^(2-) did not have significant effect on FA degradation. Fe^(3+)and Cu^(2+)benefited FA degradation through the Fenton-like and catalytic ozonation reactions.
基金supported by the National Natural Science Foundation of China (21938005 and 21776197)Key Laboratory of Coal Science and Technology, Education Ministry and Shanxi Province, Taiyuan University of Technology
文摘Sodium(Na)metal batteries with a high volumetric energy density that can be operated at high rates are highly desirable.However,an uneven Na-ion migration in bulk Na anodes leads to localized deposition/dissolution of sodium during high-rate plating/stripping behaviors,followed by severe dendrite growth and loose stacking.Herein,we engineer the Na hybrid anode with sodiophilic Na_(3)Bi-penetration to develop the abundant phase-boundary ionic transport channels.Compared to intrinsic Na,the reduced adsorption energy and ion-diffusion barrier on Na_(3)Bi ensure even Na^(+)nucleation and rapid Na^(+)migration within the hybrid electrode,leading to uniform deposition and dissolution at high current densities.Furthermore,the bismuthide enables compact Na deposition within the sodiophilic framework during cycling,thus favoring a high volumetric capacity.Consequently,the obtained anode was endowed with a high current density(up to 5 mA∙cm^(−2)),high areal capacity(up to 5 mA∙h∙cm^(−2)),and long-term cycling stability(up to 2800 h at 2 mA∙cm^(−2)).
文摘From the theoretical analysis of the thermionic emission model of current-voltage characteristics, this paper extracts the parameters for the gate Schottky contact of two ion-implanted 4H-SiC metal-semiconductor field-effect transistors （sample A and sample B for three and four times multiple ion-implantation channel region respectively） fabricated in the experiment, including the ideality factor, the series resistance, the zero-field barrier height, the interface oxide capacitance, the interface state density distribution, the neutral level of interface states and the fixed space charge density. The methods to improve the interface of the ion-implanted Schottky contact are given at last.
基金Project supported by the National Natural Science Foundation of China (Grant No. 50671048)
文摘This paper reports that the CoFe/IrMn bilayers are deposited by magnetron sputtering on the surfaces of thermallyoxidized Si substrates. It investigates the thermal relaxations of both non-irradiated and Ca^＋ ion irradiated CoFe/IrMn bilayers by means of holding the bilayers in a negative saturation field. The results show that exchange bias field decreases with the increase of holding time period for both non-irradiated and Ca^＋ ion irradiated CoFe/IrMn bilayers. Exchange bias field is also found to be smaller upon irradiation at higher ion dose. This reduction of exchange bias field is attributed to the change of energy barrier induced by ion-radiation.
基金supported by the technological project of Shenzhen, China (No.200620)Shenzhen Key Laboratory of Sensors Technology Open Fund of China (Nos.SST200908, SST200911)
文摘A spark generator was employed to assist surface barrier discharge （SBD） in nitrogen at atmospheric pressure. The influence of spark discharge on the SBD electrical behavior is investigated by means of volt-ampere characteristics. Also, the electron density of plasma in the filament of each SBD arrangement is determined by plasma radiation method. It is found that the filaments in spark-assistant SBD are much stronger, while the corresponding mean electron density is much lower. Results show that the spark generator can improve the uniformity of SBD in atmospheric nitrogen in a particular range of applied frequency.
文摘The degradation phenomena due to the energy pulse in the high-energy ZnO varistors used for deexitation and overvoltage protection of hydroelectric generator are investigated. The energy pulse, obtained by releasing the energy stored in an inductor, can be equivalent to the combination of the DC field components and the energy component. The variations of the characterized voltages, nonlinear coefficients and pre-breakdown V-A characteristics, increase with the number of the applied energy pulse. The asymmetrical variations of the electric properties of the high-energy ZnO varistors after the energy pulse arise from the deformation of the double Schottky barriers due to the ion migration occuring in the depletion layer and in the grain boundary.
基金Project supported by the Special Program for Key Basic Research of the Ministry of Science and Technology,China(Grant No.2002CCA00900)the Fundamental Research Funds for the Central Universities of Ministry of Education of China(Grant No.lzujbky-2013-5)
文摘We investigate the single-electron loss processes of light charged ions （Li^1＋,2＋, C^2＋,3＋,5＋, and O^2＋,3＋） in collisions with helium. To better understand the experimental results, we propose a theoretical model to calculate the cross section of projectile electron loss. In this model, an ionization radius of the incident ion was defined under the classical over-barrier model, and we developed ＂strings＂ to explain the processes of projectile electron loss, which is similar with the molecular over-barrier model. Theoretical calculations are in good agreement with the experimental results for the cross section of single-electron loss and the ratio of double-to-single ionization of helium associated with one-electron loss.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10275092 and 10675169.
文摘The interaction potential for spherical-deformed reaction partners is calculated. The shape, separation and orientation dependence of the interaction potential and fusion cross section of the system ^32S＋^154Sm are investigated within the double-folding model of the deformed nuclei. The effective nucleon-nucleon interaction is taken to be the M3Y-Reid potential. The density is considered for three terms of the expansion using the truncated multipole expansion method, which is a deformed Fermi shape With quadrupole and hexadecapole for the density distribution of ^154Sm. It is found for the interaction potential that the height and the position of barrier strongly depend on the deformations, the orientation angle of the deformed nucleus, and hence produce great effects on fusion cross section. The integrated fusion cross section is in good agreement with the experimental data.
