检索结果-南通市图书馆

secondary electron emission model for photo-emission from metals in the vacuum ultraviolet

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2022年第8期33卷 89-105页

作者： Ai-Gen Xie Yi-Fan Liu Hong-Jie Dong School of Physics and Optoelectronic Engineering Nanjing University of Information Science&TechnologyNanjing 210044China Jiangsu Key Laboratory for Optoelectronic Detection of Atmosphere and Ocean Nanjing University of Information Science&TechnologyNanjing 210044China Jiangsu International Joint Laboratory on Meteorological Photonics and Optoelectronic Detection Nanjing University of Information Science&TechnologyNanjing 210044China

This study investigates two secondary electron emission(SEE)models for photoelectric energy distribution curves f(E_(ph),hγ),B,E_(mean),absolute quantum efficiency(AQE),and the mean escape depth of photo-emitted electronsλof *** proposed models are developed from the density of states and the theories of photo-emission in the vacuum ultraviolet and SEE,where B is the mean probability that an internal photo-emitted electron escapes into vacuum upon reaching the emission surface of the metal,and E_(mean)is the mean energy of photo-emitted electrons measured from *** formulas for f(E_(ph),hγ),B,λ,E_(mean),and AQE that were obtained were shown to be correct for the cases of Au at hγ=8.1–11.6 eV,Ni at hγ=9.2–11.6 eV,and Cu at hγ=7.7–11.6 *** photoelectric cross sections(PCS)calculated here are analyzed,and it was confirmed that the calculated PCS of the electrons in the conduction band of Au at hγ=8.1–11.6eV,Ni at hγ=9.2–11.6 eV,and Cu at hγ=7.7–11.6 eV are correct.

关键词： Absolute quantum efficiency Photoelectric cross section Mean escape depth of photo-emitted electrons Probability Photo-emission from metals secondary electron emission Vacuum ultraviolet Mean energy of photo-emitted electrons

secondary electron emission and photoemission from a negative electron affinity semiconductor with large mean escape depth of excited electrons

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2023年第4期32卷 677-690页

作者：谢爱根董红杰刘亦凡 School of Physics and Optoelectronic Engineering Nanjing University of Information Science and TechnologyNanjing 210044China Jiangsu Key Laboratory for Optoelectronic Detection of Atmosphere and Ocean Nanjing University of Information Science&TechnologyNanjing 210044China Jiangsu international Joint Laboratory on Meteorological Photonics and Optoelectronic Detection Nanjing University of Information Science&TechnologyNanjing 210044China

The formulae for parameters of a negative electron affinity semiconductor(NEAS)with large mean escape depth of secondary electrons A(NEASLD)are *** methods for obtaining parameters such asλ,B,E_(pom)and the maximumδandδat 100.0 keV≥E_(po)≥1.0 keV of a NEASLD with the deduced formulae are presented(B is the probability that an internal secondary electron escapes into the vacuum upon reaching the emission surface of the emitter,δis the secondary electron yield,E_(po)is the incident energy of primary electrons and E_(pom)is the E_(po)corresponding to the maximumδ).The parameters obtained here are analyzed,and it can be concluded that several parameters of NEASLDs obtained by the methods presented here agree with those obtained by other *** relation between the secondary electron emission and photoemission from a NEAS with large mean escape depth of excited electrons is investigated,and it is concluded that the presented method of obtaining A is more accurate than that of obtaining the corresponding parameter for a NEAS with largeλ_(ph)(λ_(ph)being the mean escape depth of photoelectrons),and that the presented method of calculating B at E_(po)>10.0 keV is more widely applicable for obtaining the corresponding parameters for a NEAS with largeλ_(ph).

关键词： negative electron affinity semiconductor secondary electron emission photoemission the probability secondary electron yield large mean escape depth of excited electrons

On characteristics of sheath damping near a dielectric wall with secondary electron emission

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2011年第6期20卷 317-322页

作者：于达仁卿绍伟闫国军段萍 School of Energy Science and Engineering Harbin Institute of Technology School of Physics Dalian Maritime University

A preliminary investigation is conducted to study the characteristics of sheath damping near a dielectric wall with secondary electron emission （SEE）. Making use of the linear analysis of the sheath stability, we have found two major contributions to the sheath damping, one similar to the Landau damping in uniform plasmas and another determined by local electric field and electron density of the steady-state sheath. It indicates that in a classical sheath regime the damping in the sheath region monotonically increases towards the wall and decreases with the enhancement of SEE effect. In order to verify the theoretical analysis, sheath oscillation processes induced by an initial disturbance are simulated with a time-dependent one-dimensional （1D） sheath model. Numerical results obtained are consistent with the theoretical analysis qualitatively.

关键词： plasma sheath damping electron electrostatic wave secondary electron emission

Nonlinear change of ion-induced secondary electron emission in theκ-Al_(2)O_(3) surface charging from first-principle modelling

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2024年第9期26卷 40-50页

作者： Zhicheng JIAO Mingrui ZHU Dong DAI Tao SHAO Buang WANG South China University of Technology Guangzhou 510641People’s Republic of China Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100190People’s Republic of China University of Richmond Richmond 23173United States of America

secondary electron emission(SEE)induced by the positive ion is an essential physical process to influence the dynamics of gas discharge which relies on the specific surface *** charging has a significant impact on the material properties,thereby affecting the SEE in the plasma-surface ***,it does not attract enough attention in the previous *** this paper,SEE dependent on the charged surface of specific materials is described with the computational method combining a density functional theory(DFT)model from the first-principle theory and the theory of Auger *** effect ofκ-Al2O3 surface charge,as an example,on the ion-induced secondary electron emission coefficient(SEEC)is investigated by analyzing the defect energy level and band structure on the charged *** results indicate that,with the surface charge from negative to positive,the SEEC of a part of low ionization energy ions(such as Ei=12.6 eV)increases first and then decreases,exhibiting a nonlinear changing *** is quite different from the monotonic decreasing tendency observed in the previous model which simplifies the electronic *** irregular increase of the SEEC can be attributed to the lower escaped probability of orbital *** results further illustrate that the excessive charge could cause the bottom of the conduction band close to the valence band,thus leading to the decrease of the orbital energy occupied by the excited *** nonlinear change of SEEC demonstrates a more realistic situation of how the electronic structure of material surface influences the SEE *** work provides an accurate method of calculating SEEC from specific materials,which is urgent in widespread physical scenarios sensitive to surface materials,such as increasingly growing practical applications concerning plasma-surface interactions.

关键词： secondary electron emission charged surface density functional theory defect energy level

Characteristics of wall sheath and secondary electron emission under different electron temperatures in a Hall thruster

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2014年第7期23卷 510-515页

作者：段萍覃海娟周新维曹安宁陈龙高宏 Department of Physics Dalian Maritime University School of Physics and Optoelectronic Technology Dalian University of Technology

In this paper, a two-dimensional physical model is established in a Hall thruster sheath region to investigate the influences of the electron temperature and the propellant on the sheath potential drop and the secondary electron emission in the Hall thruster, by the particle-in-cell （PIC） method. The numerical results show that when the electron temperature is relatively low, the change of sheath potential drop is relatively large, the surface potential maintains a stable value and the stability of the sheath is good. When the electron temperature is relatively high, the surface potential maintains a persistent oscillation, and the stability of the sheath reduces. As the electron temperature increases, the secondary electron emission coefficient on the wall increases. For three kinds of propellants （At, Kr, and Xe）, as the ion mass increases the sheath potentials and the secondary electron emission coefficients reduce in sequence.

关键词： Hall thruster electron temperature sheath secondary electron emission

Characteristics of secondary electron emission from few layer graphene on silicon(111) surface

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2022年第10期31卷 549-562页

作者： Guo-Bao Feng Yun Li Xiao-Jun Li Gui-Bai Xie Lu Liu National Key Laboratory of Science and Technology on Space Microwave China Academy of Space TechnologyXi’an 710100China School of Computer Science and Engineering Xi’an University of TechnologyXi’an 710048China

As a typical two-dimensional(2D) coating material, graphene has been utilized to effectively reduce secondary electron emission from the surface. Nevertheless, the microscopic mechanism and the dominant factor of secondary electron emission suppression remain controversial. Since traditional models rely on the data of experimental bulk properties which are scarcely appropriate to the 2D coating situation, this paper presents the first-principles-based numerical calculations of the electron interaction and emission process for monolayer and multilayer graphene on silicon(111) substrate. By using the anisotropic energy loss for the coating graphene, the electron transport process can be described more realistically. The real physical electron interactions, including the elastic scattering of electron-nucleus, inelastic scattering of the electron-extranuclear electron, and electron-phonon effect, are considered and calculated by using the Monte Carlo method. The energy level transition theory-based first-principles method and the full Penn algorithm are used to calculate the energy loss function during the inelastic scattering. Variations of the energy loss function and interface electron density differences for 1 to 4 layer graphene coating Go Si are calculated, and their inner electron distributions and secondary electron emissions are analyzed. Simulation results demonstrate that the dominant factor of the inhibiting of secondary electron yield(SEY) of Go Si is to induce the deeper electrons in the internal scattering process. In contrast, a low surface potential barrier due to the positive deviation of electron density difference at monolayer Go Si interface in turn weakens the suppression of secondary electron emission of the graphene layer. Only when the graphene layer number is 3, does the contribution of surface work function to the secondary electron emission suppression appear to be slightly positive.

关键词： secondary electron emission graphene on silicon numerical simulation

A novel double dielectric barrier discharge reactor with high field emission and secondary electron emission for toluene abatement

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2022年第1期24卷 118-128页

作者： Shijie LI Xin YU Xiaoqing DANG Pengyong WANG Xiangkang MENG Huachun ZHENG School of Environment&Municipal Engineering Xi'an University of Architecture&TechnologyXi'an 710055People’s Republic of China Shaanxi Key Laboratory of Environmental Engineering Xi'an University of Architecture&TechnologyXi’an 710055People’s Republic of China Key Laboratory of Northwest Water Resources Environment and EcologyMinistry of EducationXi'an University of Architecture and TechnologyXi’an 710055People’s Republic of China

Dielectric barrier discharge(DBD)has been extensively investigated in the fields of environment and energy,whereas its practical implementation is still limited due to its unsatisfactory energy *** order to improve the energy efficiency of DBD,a novel double dielectric barrier discharge(NDDBD)reactor with high field emission and secondary electron emission was developed and compared with traditional DDBD(TDDBD)***,the discharge characteristics of the two DDBD reactors were *** to TDDBD,the NDDBD reactor exhibited much stronger discharge intensity,higher transferred charge,dissipated power and gas temperature due to the effective utilization of cathode field emission and secondary electron ***,toluene abatement performance of the two reactors was *** toluene decomposition efficiency and mineralization rate of NDDBD were much higher than that of TDDBD,which were 86.44%-100%versus 28.17%-80.48%and 17.16%-43.42%versus 7.17%-16.44%at 2.17-15.12 W and 1.24-4.90 W *** also exhibited higher energy yield than TDDBD,whereas the overall energy constant k_(overall)of the two reactors were ***,plausible toluene decomposition pathway in TDDBD and NDDBD was suggested based on organic intermediates that generated from toluene *** finding of this study is expected to provide reference for the design and optimization of DBD reactor for volatile organic compounds control and other applications.

关键词： toluene removal double dielectric barrier discharge field emission secondary electron emission decomposition mechanism

Effect of secondary electron emission on the Sheath in SPT Chamber

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2009年第1期11卷 57-61页

作者：薛中华赵晓云王丰刘金远刘悦宫野 School of Physics and Optoelectronic Technology and College of Advanced Science and Technology Dalian University of Technology

A one-dimensional slab model of the plasma sheath in the stationary plasma thruster （SPT） chamber is developed in this study. It is considered that secondary electrons emitted from ceramic walls are partially trapped by the bulk plasma in the SPT chamber; some secondary electrons drift across the sheath where they are generated and the bulk and move towards the opposite sheath. Thus both the secondary electron emission （SEE） from one sheath and the partially trapped secondary electrons from the opposite sheath contribute to this sheath. The results indicate that both the SEE coefficient and trapping coefficient have a significant impact not only on the distributions of both electrons and ions of the SPT sheath but also on the energy flux loss to the SPT wall. When the trapping coefficient increases, the energy flux of electrons deposited to the walls will increase whereas that of ions will decrease. Besides, the critical electron temperature will decrease greatly with the increase of the trapping coefficient.

关键词： stationary plasma thruster secondary electron emission sheath

The New Model Based on secondary electron emission of Solid Materials on Its Electrostatic Electrification

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of electronics 2015年第3期24卷 445-448页

作者： CHANG Tianhai WU Shuling School of electronic and Information Engineering South China University of Technology

As the study to innovate and develop a new research direction of electrostatic theory, it is known that secondary electron emission coefficient of solid material can't be ignored as an important and incentive parameter of static electricity. In this paper, we combined the experiment with theoretical way to discuss and analyze the association mechanism between the magnitude and polarity of surface electrostatic potential with the secondary electron emission characteristic, as well as tried to explore and establish the new model based on secondary electron emission characteristics with solid surface electrostatic charging.

关键词： Solid material secondary electron emission Electrostatic electrification Relevance mechanism New theoretic model