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First-principles investigations of proton generation inα-quartz

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Chinese Physics B 2018年第3期27卷 368-375页

作者： Yunliang Yue Yu Song Xu Zuo College of Electronic Information and Optical Engineering Nankal UniversityTianjin 300071China Microsystem and Terahertz research Center China Academy of Engineering PhysicsChengdu 610200China Institute of Electronic Engineering China Academy of Engineering PhysicsMianyang 621999China Municipal Key Laboratory of Photo-electronic Thin Film Devices and Technology Nankai UniversityTianjin 300071China

Proton plays a key role in the interface-trap formation that is one of the primary reliability concerns, thus learning how it behaves is key to understand the radiation response of microelectronic devices. The first-principles calculations have been applied to explore the defects and their reactions associated with the proton release in a-quartz, the well-known crystalline isomer of amorphous silica. When a high concentration of molecular hydrogen （H2） is present, the proton generation can be enhanced by cracking the He molecules at the positively charged oxygen vacancies in dimer configuration. If the concentration of molecular hydrogen is low, the proton generation mainly depends on the proton dissociation of the doubly- hydrogenated defects. In particular, a fully passivated E~ center can dissociate to release a proton barrierlessly by structure relaxation once trapping a hole. This research provides a microscopic insight into the proton release in silicon dioxide, the critical step associated with the interface-trap formation under radiation in microelectronic devices.

关键词： first-principles calculation interface trap proton silicon dioxide

Spin-polarized current in double quantum dots

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Chinese Physics B 2012年第11期21卷 383-387页

作者：李爱仙段素青 Graduate School of China Academy of Engineering Physics Institute of Applied Physics and Computational Mathematics

We analyze the transport through asymmetric double quantum dots with an inhomogeneous Zeeman splitting in the presence of crossed dc and ac magnetic fields. A strong spin-polarized current can be obtained by changing the dc magnetic field. It is mainly due to the resonant tunnelling. But for the ferromagnetic right electrode, the electron spin resonance also plays an important role in transport. We show that the double quantum dots with three-level mixing under crossed dc and ac magnetic fields can act not only as a bipolar spin filter but also as a spin inverter under suitable conditions.

关键词： resonant tunnelling spin-polarized current spin filter double quantum dots

Nonsequential double ionization of the aligned hydrogen molecule in strong field

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Chinese Physics B 2010年第4期19卷 218-222页

作者：李燕杨世平贾欣燕陈京 Department of Physics Hebei Normal University Institute of Applied Physics and Computational Mathematics Center for Applied Physics and Technology Peking University

This paper studies the nonsequential double ionization （NSDI） process of diatomic molecules aligned parallel and perpendicular to an intense linearly polarized laser field by using a three-dimensional semiclassical model. With this model, it achieves insight into the ion momentum distribution under the combined influence of a two-centre Coulomb potential and an intense laser field, and this result shows the significant influence of molecular alignment on the ratio between double and single ionization rate. Careful investigations show that the NSDI process for different alignment molecules has a close relation to the laser intensity and the different bounding electron distribution has a significant influence on the final ion momentum distribution.

关键词： nonsequential double ionization ionization probability alignment molecule

Fabrication processing effects on the microstructure and morphology of erbium film

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Chinese Physics B 2012年第7期21卷 396-402页

作者：申华海彭述明龙兴贵周晓松杨莉刘锦华孙庆强祖小涛 Department of Applied Physics University of Electronic Science and Technology of China Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics

The effect of substrate temperature on the microstructure and the morphology of erbium film are systematically investigated using X-ray diffraction （XRD） and scanning electron microscopy （SEM）. All the erbium films are grown by electron-beam vapor deposition （EBVD）. A novel preparation method for observing the cross-section morphology of the erbium film is developed. The films deposited at 200 ℃ have （002） preferred orientation, and the films deposited at 450 ℃ have a mixed （100） and （101） texture, due to the different growth mechanisms of surface energy minimization and recrystallization, respectively. The peak positions and the full widths at half maximum （FWHMs） of erbium diffraction lines （100）, （002）, and （101） shift towards higher angles and decrease with the increasing substrate temperature in a largely uniform manner, respectively. Also, the lattice constants decrease with increasing temperature. The transition in the film stresses can be used to interpret the changes in peak positions, FWHMs, and lattice constants. The stress is compressive for the as-growth fihns, and is counteracted by the tensile stress formed during the process of temperature cooling to room temperature. The tensile stress mainly originates from the difference in the coefficients of thermal expansion of the substrate-film couple.

关键词： erbium film substrate temperature preferred orientation columnar grain

Influences of annealing on structural and compositional properties of Al_2O_3 thin films grown on 4H–SiC by atomic layer deposition

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Chinese Physics B 2016年第12期25卷 468-473页

作者：田丽欣张峰申占伟闫果果刘兴昉赵万顺王雷孙国胜曾一平 Key Laboratory of Semiconductor Material Sciences Beijing Key Laboratory of Low Dimensional Semiconductor Materials and DevicesInstitute of SemiconductorsChinese Academy of Sciences

Annealing effects on structural and compositional performances of A1203 thin films on 4H-SiC substrates are studied comprehensively. The Al2O3 films are grown by atomic layer deposition through using trimethylaluminum and H2O as precursors at 300 ℃, and annealed at various temperatures in ambient N2 for 1 min. The Al2O3 film transits from amorphous phase to crystalline phase as annealing temperature increases from 750 ℃ to 768 ℃. The refractive index increases with annealing temperature rising, which indicates that densification occurs during annealing. The densification and grain formation of the film upon annealing are due to crystallization which is relative with second-nearest-neighbor coordination variation according to the x-ray photoelectron spectroscopy （XPS）. Although the binding energies of Al 2p and O ls increase together during crystallization, separations between Al 2p and O ls are identical between as-deposited and annealed sample, which suggests that the nearest-neighbour coordination is similar.

关键词： atomic layer deposition annealing transition 4H-SiC

A fitting formula for electron–ion energy partition fraction of 3.54-MeV fusion alpha particles in hot dense deuterium–tritium plasmas

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Chinese Physics B 2021年第1期30卷 345-349页

作者： Yan-Ning Zhang Zhi-Gang Wang Yong-Tao Zhao Bin He School of Science Xi’an Jiaotong UniversityXi’an 710049China Institute of Applied Physics and Computational Mathematics Beijing 100088China

Based on our previous work(*** 25 012704(2018)),a fitting formula is given for electron-ion energy partition fraction of 3.54-MeV fusion alpha particles in deuterium-tritium(DT) plasmas as a function of plasma mass density ρ,electron temperature T_(e),and ion temperature T_(i).The formula can be used in a huge range of the plasma state,where ρ varies between 1.0 g/cc~10.0^(3) g/cc and both T_(e) and T_(i) change from 0.1 keV to 100.0 *** effect for electrons is investigated including the effect of the projectile recoil in the plasmas at T_(e)≥ 50.0 *** partition fraction for T_(e)>T_(i) is found to be close to that for T_(e)=T_(i). The comparisons with other fitting results are made at some plasma densities when T_(e)=T_(i),and the difference is *** fitting result is very close to the calculated one in most cases,which is convenient for the simulation of alpha heating in hot dense DT plasmas for inertial confined fusion.

关键词： inertial confinement fusion deuterium–tritium plasma alpha heating energy loss

High Temperature Melting Curve of Basaltic Glass by Laser Flash Heating

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Chinese Physics Letters 2022年第2期39卷 15-20页

作者： Yukai Zhuang Junwei Li Wenhua Lu Xueping Yang Zhixue Du Qingyang Hu Institute of Atomic and Molecular Physics Sichuan UniversityChengdu 610065China Center for High Pressure Science and Technology Advanced research(HPSTAR) Beijing 100094China State Key Laboratory of Isotope Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China Center for Excellence in Deep Earth Science Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China

Basalt is an igneous rock originating from the cooling and solidification of magma and covers approximately 70% of Earth’s *** glass melting in the deep Earth is a fundamental subject of research for understanding geophysics,geochemistry,and geodynamic *** this study,we design a laser flash heating system using two-dimensional,four-color multi-wavelength imaging radiometry to measure the basaltic glass melting temperature under high pressure conditions in diamond anvil *** experiment not only determines the temperature at the center of heating but also constructs a temperature distribution map for the surface heating area,and enables us to assess the temperature *** precise temperature measurements,we observe that the basaltic glass melting temperature is higher than those in previous reports,which is near the normal upper-mantle isotherm,approaching the hot *** suggests that basalt should not melt in most of the normal upper mantle and the basaltic melts could exist in some hot regions.

关键词： basalt mantle Earth

Effective extraction of photoneutron cross-section distribution using gamma activation and reaction yield ratio method

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Nuclear Science and Techniques 2023年第11期34卷 103-111页

作者： Zhi‑Cai Li Yue Yang Zong‑Wei Cao Xin‑Xiang Li Yun Yuan Zong‑Qing Zhao Gong‑Tao Fan Hong‑Wei Wang Wen Luo School of Nuclear Science and Technology University of South ChinaHengyang 421001China Science and Technology on Plasma Physics Laboratory Laser Fusion Research CenterChina Academy of Engineering PhysicsMianyang 621900China Shanghai Advanced research Institute Chinese Academy of SciencesShanghai 201210China

Photoneutron cross-section(PNCS)data are important in various current and emerging *** a few sophis-ticated methods have been developed,there is still an urgent need to study the PNCS *** this study,we propose the extraction of PNCS distributions using a combination of gamma activation and reaction yield ratio *** verify the validity of the proposed extraction method,experiments for generating^(62,64)Cu and^(85m,87m)Sr isotopes via laser-induced pho-toneutron reactions were performed,and the reaction yields of these isotopes were *** the proposed extraction method,the PNCS distributions of^(63)Cu and^(86)Sr isotopes(leading to^(85m)Sr isotope production)were successfully *** extracted PNCS distributions were benchmarked against available PNCS data or TALYS calculations,demonstrating the validity of the proposed extraction *** applications for predicting the PNCS distributions of the 30 iso-topes are further *** conclude that the proposed extraction method is an effective complement to the available sophisticated methods for measuring and evaluating PNCS data.

关键词： Photonuclear data Photoneutron cross section Gamma activation Reaction yield TALYS calculation

A Conservative Lagrangian Scheme for Solving Compressible Fluid Flows with Multiple Internal Energy Equations

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Communications in Computational Physics 2012年第10期12卷 1307-1328页

作者： Juan Cheng Chi-Wang Shu Qinghong Zeng National Key Laboratory of Science and Technology on Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China Division of Applied Mathematics Brown UniversityProvidenceRI 02912USA Institute of Applied Physics and Computational Mathematics Beijing 100088China

Lagrangianmethods arewidely used inmany fields formulti-material compressible flow simulations such as in astrophysics and inertial confinement fusion(ICF),due to their distinguished advantage in capturing material interfaces *** some of these applications,multiple internal energy equations such as those for electron,ion and radiation are *** the past decades,several staggeredgrid based Lagrangian schemes have been developed which are designed to solve the internal energy equation *** schemes can be easily extended to solve problems with multiple internal energy *** such schemes are typically not conservative for the total ***,significant progress has been made in developing cell-centered Lagrangian schemes which have several good properties such as conservation for all the conserved variables and easiness for ***,these schemes are commonly designed to solve the Euler equations in the form of the total energy,therefore they cannot be directly applied to the solution of either the single internal energy equation or the multiple internal energy equations without significant *** modifications,if not designed carefully,may lead to the loss of some of the nice properties of the original schemes such as conservation of the total *** this paper,we establish an equivalency relationship between the cell-centered discretizations of the Euler equations in the forms of the total energy and of the internal *** a carefully designed modification in the implementation,the cell-centered Lagrangian scheme can be used to solve the compressible fluid flow with one or multiple internal energy equations and meanwhile it does not lose its total energy conservation *** advantage of this approach is that it can be easily applied to many existing large application codes which are based on the framework of solving multiple internal energy *** two dimensional numerical examp

关键词： Lagrangian scheme conservative cell-centered internal energy equation compressible fluid flow three-temperaturemodel