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progress in Natural Science:materials International 2009年第6期19卷 677-684页

作者： Xiang Xu, Hao Ge, Shuai Wang, Zhongling Dai, Younian Wang , Aimin Zhu state key Lab of materials modification by electron, ion and laser beams, School of physics and Optoelectronic technology, dalian university of technology, dalian 116023, china [a]state key Lab of materials modification by electron Ion and Laser Beams School of Physics and Optoelectronic Technology Dalian University of Technology Dalian 116023 China

A two-dimensional (2D) fluid model is presented to study the discharge of argon in a dual frequency capacitively coupled plasma (CCp) reactor. We are interested in the influence of low-frequency (LF) source parameters such as applied voltage amplitudes and low frequencies on the plasma characteristics. In this paper, the high frequency is set to 60 MHz with voltage 50 V. The simulations were carried out for low frequencies of 1, 2 and 6 MHz with LF voltage 100 V, and for LF voltages of 60, 90 and 120 V with low frequency 2 MHz. The results of 2D distributions of electric field and ion density, the ion flux impinging on the substrate and the ion energy on the powered electrode are shown. As the low frequency increases, two sources become from uncoupling to coupling. When two sources are uncoupling, the increase in LF has little impact on the plasma characteristics, but when two sources are coupling, the increase in LF decreases the uniformities of ion density and ion flux noticeably. It is also found that with the increase in LF voltage, the uniformities in the radial direction of ion density distribution and ion flux at the powered electrode decreases significantly, and the energy of ions bombarding on the powered electrode increases significantly.

关键词： Dual frequency Capacitively coupled plasma Fluid simulation

Online diagnosis of electron excitation temperature in CH_4+H_2 discharge plasma at atmospheric pressure by optical emission spectra

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Science china(physics,Mechanics & Astronomy) 2008年第12期51卷 1892-1896页

作者： CUI JinHua1, XU ZhenFeng2, ZHANG JiaLiang3↑, NIE QiuYue3, XU GenHui4 & rEN LongLiang5 1 Faculty of Chemistry and Chemical Engineering, Liaoning Normal university, dalian 116021, china 2 Technique Center for Modern Education, Liaodong College, Dandong 126709, china 3 state key laboratory for materials modification by laser, ion and electron beams, dalian university of technology, dalian 116023, china 4 College of Chemical Engineering, Tianjin university, Tianjin 300072, china 5 department of physics, Science College, Tianjin university, Tianjin 300072, china 1. Faculty of Chemistry and Chemical Engineering Liaoning Normal University Dalian 116021 China 2. Technique Center for Modern Education Liaodong College Dandong 126709 China 3. state key laboratory for materials modification by laser Ion and Electron Beams Dalian University of Technology Dalian 116023 China 4. College of Chemical Engineering Tianjin University Tianjin 300072 China 5. department of physics Science College Tianjin University Tianjin 300072 China

Methane coupling under low temperature plasmas at atmospheric pressure is a green process by use of renewable sources of energy. In this study, CH4+H2 dis- charge plasma was on-line diagnosed by optical emission spectra so as to char- acterize the discharge system and to do spade work for the optimization of the technical parameters for future commercial production of methane coupling under plasmas. The study was focused on a calculation method for the online diagnosis of the electron excitation temperature in CH4+H2 discharge plasma at atmospheric pressure. The diagnostic method is easy, efficient and fairly precise. A serious er- ror in a literature was corrected during the reasoning of its series of equations formerly used to calculate electron temperatures in plasmas.

关键词： low temperature plasma electron excitation temperature optical emission spectrum online diagnosis

The Effect of Intensity pulsed ion Beam Irradiation on Wear resistance of High-speed Steel

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材料热处理学报 2004年第5B期25卷 1049-1052页

作者： MEIXian-xiu HAOSheng-zhi MATeng-cai WANGYing-min LIUZhen-min statekeylaboratoryformaterialsmodificationbylaser IonandElectronBeamsDepartmentofPhysicsDalianUniversityofTechnologyDalian116024China

The structural and phase transformations occurring in the near-surface layers of pre-quenched W6Mo5Cr4V2 high-speed steel (HSS) subjected to intensity pulsed ion beam (IpIB) melting have been investigated. The effect of IpIB irradiation on wear resistance of the HSS has also been studied. The IpIB consists mainly of Cn+(30%)^0 H+(70%), with a high beam current density of 80A/cm2, acceleration voltage of 250kV, pulse duration of 70 ns. Samples were bombarded with 1, 3, 5 pulses respectively. It has been revealed that after IpIB irradiation the initial martensite in the near-surface layer of HSS changed into austenite and produced residual stresses by using electron microscopy and X-ray diffraction. redistribution and interlace of dislocations in the irradiated samples were generated under the impact of shock wave. With increasing pulse times gradual liquid-phase dissolution of M6C carbide particles occurs in the near-surface layer and produces nanocrystalline MC. This process results in the decrease of martensite crystal (a-phase) and increase of austenite (y-phase) content and the dispersed carbide. Wear resistance of the HSS is improved by a factor of 2, which is explained by the formation of metastable phases such nanocrystal and residual stresses and the redistribution and interlace of dislocations.

关键词：高速钢磨损性能强脉冲离子束热处理

Chemical Structure of Carbon Nitride Films prepared by MW-ECr plasma Enhanced Magnetron Sputtering

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材料热处理学报 2004年第5B期25卷 818-820页

作者： XUJun,GAOpeng DINGWan-yu LIXin DENGXin-lu DONGChuang statekeyLab.formaterialsmodificationbylaser IonandElectronBeamsDepartmentofPhysicsDalianUniversityofTechnologyDalian116024P.R.China

Amorphous carbon nitride thin films were prepared by plasma-enhanced DC magnetron sputtering using twinned microwave electron cyclotron resonance plasma sources. Chemical structure of deposited films was investigated using X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The results indicate that the deposition rate is strongly affected by direct current bias, and the films are mainly composed of a single amorphous carbon nitride phase with N/C ratio close to C3N4, and the bonding is predominantly of C^N type.

关键词：碳氮化物 MW-ECr 磁控管溅射等离子增强沉积化学结构

尾流效应对快速双原子分子离子在固体中电荷态及分子轴取向的影响

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物理学报 2002年第4期51卷 857-862页

作者：王友年李宏伟大连理工大学物理系大连理工大学物理系三束材料改性国家重点实验室大连116024

研究了快速双原子分子离子在固体中穿行时 ,尾流效应对各离子电荷态以及库仑爆炸过程的影响 .借助于线性介电响应理论和局域介电函数 ,离子之间的动力学相互作用势可以表示成对称的屏蔽库仑势和非对称的尾势 .通过对分子离子上所有束缚... 详细信息

研究了快速双原子分子离子在固体中穿行时 ,尾流效应对各离子电荷态以及库仑爆炸过程的影响 .借助于线性介电响应理论和局域介电函数 ,离子之间的动力学相互作用势可以表示成对称的屏蔽库仑势和非对称的尾势 .通过对分子离子上所有束缚电子的总能量进行变分和求解单个离子的运动方程 ,自洽地确定出分子离子中每个离子的电荷态 .数值结果表明 ,由于尾流效应的影响 ,在初始穿行阶段 ,分子离子中导航离子的电荷数随穿行深度的增加而单调递增 ,而尾随离子的电荷数则随穿行深度的增加而振荡 .但当穿行深度很大时 ,两个离子的电荷数都趋于具有相同速度的孤立离子的电荷数 .此外 ,还发现分子轴的取向朝入射速度方向偏转

关键词：分子离子尾流效应电荷态库仑爆炸

phase Conjugation by Degenerate Four-wave Mixing in Nematic Liquid Crystals

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Chinese Journal of lasers 1997年第5期B6卷 403-408页

作者： ZHONG Xiaoxia WU Jiada CHEN Shuchao WU Changzheng LI Fuming (state key Joint Lab for materials modification by laser, ion and electron beams department of physics, Fudan university, Shanghai 200433, chinadepartment of physics Xiamen university, Xiamen 3 Fudan Univ Shanghai China

phase conjugation by degenerate four-wave mixing(DFWM) due to the optically induced molecular reorientation in nematic liquid crystals(NLC) is studied, and an analytical expression for the efficiency of phase conjugation is presented. Calculations of the efficiency are given for 5CB liquid crystal for further investigstion of the dependences of the phase conjugation on the angle between the pump beam and the probe beam as well as on the angle between the plane of the incident beams and the nematic director n. The physical mechanism is also discussed.

关键词： nematic liquid crystal four-wave mixing phase conjugation

MEAM potential with Angular Dependence for TiAl

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rare Metals 2001年第1期20卷 13-17页

作者： Xiaodong Ni, Xitao Wang, Guoliang Chen (physics department, university of Science and technology Beijing, Beijing 100083, china state key laboratory for Advanced Metals and materials, university of Science and technology Beijing, Beijing 100083, china) Univ Sci & Technol Beijing Dept Phys Beijing 100083 Peoples R China Univ Sci & Technol Beijing State Key Lab Adv Met & Mat Beijing 100083 Peoples R China

The modified embedded atom method (MEAM) is an empirical extension of the embedded atom method (EAM) that includes angular forces. By fitted to the lattice constants, the cohesive energy, the ApE (anti-phase boundary) energy, and the vacancy formation energy of TiAl, an accurate MEAM potential is obtained for the TiAl system with L10 structure. The calculation results of the properties of TiAl are in good agreement with experiments and the results of first principle (F.p.) calculations.

关键词： embedded atom method TiAl alloy angular dependence potential intermetallics

CALCULATion OF 3-D TrANSIENT TEMpErATUrE FIELD DUrING laser TrANSFOrMATion HArDENING prOCESS

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Acta Metallurgica Sinica(English Letters) 2000年第2期13卷 806-810页

作者： L. W Zhang, r.S. Wang, J. Th.M.De Hosson, Y.L. Xia and F. G. Wang 1) The state key Lab. for materials modification by laser, ion and electron beams, dalian university of technology, dalian 116023, china 2) department of Applied physics, university of Gro

A three-dimensional transient heat transfer model for laser transformation hardening process has been developed in this paper. The finite size of the laser treated sample, the surface heat loss of the sample, the latent heat of phase transformation and the temperature dependence of thermal properties of materials were considered. The heat source was considered as a moving Gaussian heat flux with a constant velocity. Three-dimension unequally spatial grid explicit finite difference equations, alternating direction implicit finite difference equations and implicit finite difference equations were deduced respectively. Three programs to calculate the temperature field were developed using Fortran language. The transient temperature fields of C22, 42CrMo, C60 steel samples during laser transformation hardening process were calculated using these programs, and the widths and depths of laser transformation hardening zones were also predicted. C22, 42CrMo, C60 steel samples were treated by CO_2 laser,the widths and depths of laser transformation hardening zones of these samples were also measured experimentally. The calculated widths and depths of laser transformation hardening zones are in good agreement with the experimental results.

关键词： temperature field laser transformation hardening steel

Shape phase transitions in nuclei:Effective order parameters and trajectories

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Science china(physics,Mechanics & Astronomy) 2011年第S1期54卷 88-97页

作者： ZHANG Yu1,2, HOU ZhanFeng2 & LIU YuXin2,3 1department of physics, Liaoning Normal university, dalian 116029, china 2department of physics and the state key laboratory of Nuclear physics and technology, peking university, Beijing 100871, china 3Center of Theoretical Nuclear physics, National laboratory of Heavy ion Accelerator, Lanzhou 720000, china 1. department of physics Liaoning Normal University Dalian 116029 China2. Department of Physics and the State Key Laboratory of Nuclear Physics and Technology Peking University Beijing 100871 China3. Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator Lanzhou 720000 China

We analyze systematically the effective order parameters in nuclear shape phase transition both in experiments and in the interacting boson model. We find that energy ratios and B(E2) ratios can distinguish the first from the second-order phase transition in theory above a certain boson number N (about 50), but in experiments, only those quantities, such as E(L1+)/E(02+) and B(E2; (L+2)1 → L1)/B(E2; 21 → 01), etc., of which the monotonous transitional behavior in the second-order phase transition is broken in the first order phase transition independent of N, are qualified as the effective order parameters. By implementing the originally proposed effective order parameters and the new ones, we find that the isotones with neutron number Nn = 62 are a trajectory of the second order phase transition. In addition, we predict that the transitional behavior of isomer shifts of Xe, Ba isotopes and Nn = 62 isotones is approximately monotonous due to the finiteness of nuclear system.

关键词： nuclear shape phase transition interacting boson model effective order parameter finite particle number effect transition trajectory