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X-ray spectra induced by ^(12.)Xe^(q+) impacting the metal surface

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Science China(physics,Mechanics & Astronomy) 2008年第1期51卷 82-89页

作者： ZHANG XiaoAn 1,2.,XIAO GuoQing 1 ,YANG ZhiHu 1 ,CHEN XiMeng 3.,ZHAO YongTao 1 , LI FuLi 4 ,WANG Li 1,2.,CUI Ying 3.,ZHANG HongQiang 3.&ZHAN WenLong 1 1Institute of Modern physics,Chinese Academy of Sciences,Lanzhou 73.000,China 2.1} of physics,{3. normal University,{3. 712.00,China 3.9} of Modern physics,Lanzhou University,Lanzhou 73.000,China 4department of Applied physics,Xi’an Jiaotong University,Xi’an 710049,China 1. Institute of Modern physics Chinese Academy of Sciences Lanzhou 730000 China 2. department of physics Xianyang Normal University Xianyang 712000 China 3. department of Modern physics Lanzhou University Lanzhou 730000 China 4. department of Applied physics Xi’an Jiaotong University Xi’an 710049 China

Using the slow highly charged ions 12. Xe q+ (q=2.,2.,2.;initial kinetic T0≤4.65 keV/a.u.)to impact Au surface,the Au atomic Mαcharacteristic X-ray spectrum is *** result shows that as long as the charge state of projectile is high enough,the heavy atomic characteristic X-ray can be effectively excited even though the incident beam is very weak(nA magnitude),and the X-ray yield per ion is in the order of 10-8and increases with the kinetic energy and potential energy of *** measuring the Au Mα-X-ray spectra,Au atomic N-level lifetime is estimated at about 1.3.×10-18s based on Heisenberg uncertainty relation.

关键词： slow highly charged ions characteristic X-ray level lifetime

X-ray spectra induced by slow highly charged Ar^(q+) ions in collision with Nb surface

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Science China(physics,Mechanics & Astronomy) 2008年第10期51卷 1463-1469页

作者： YANG ZhiHu1, CUI Ying2. CHEN XiMeng2. SONG ZhangYong1, SHAO JianXiong2. RUAN FangFang1, ZHANG HongQiang2. DU Juan2. LIU YuWen2. GAO ZhiMing2. ZHANG XiaoAn3. ZHU KeXin1, YU DeYang1 & CAI XiaoHong1 1 Institute of Modern physics, Chinese Academy of Sciences, Lanzhou 73.000, China 2.department of Modern physics, Lanzhou University, Lanzhou 73.000, China 3.department of physics, {13. normal College, xianyang 712.00, China 1. Institute of Modern physics Chinese Academy of Sciences Lanzhou 730000 China 2. department of Modern physics Lanzhou University Lanzhou 730000 China 3. department of physics Xianyang Normal College Xianyang 712000 China

The X-ray spectra of Nb surface induced by Arq+ (q =16,17) ions with the energy range from 10 to 2. keV/q were studied by the optical spectrum technology. The experimental results indicate that the multi-electron excitation occurred as a highly charged Ar16+ ion was neutralized below the metal surface. The K shell electron of Ar16+ was excited and then de-excited cascadly to emit K X-ray. The intensity of the X-ray emitted from K shell of the hollow Ar atom decreased with the increase of projectile kinetic energy. The intensity of the X-ray emitted from L shell of the target atom Nb increased with the increase of projectile kinetic energy. The X-ray yield of Ar17+ is three magnitude orders larger than that of Ar16+.

关键词： highly charged ion hollow atom multi-electron X-ray

Near infrared lights emission of ^(40)Ar^(16+) impacting on metal surfaces

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Science China(physics,Mechanics & Astronomy) 2009年第7期52卷 1021-1026页

作者： ZHANG XiaoAn1,2. XIAO GuoQing2. YANG ZhiHu2. WANG Li1 & ZHAN WenLong2.1 department of physics, {2. {3. University, xianyang 712.00, China 2.Institute of Modern physics, Chinese Academy of Sciences, Lanzhou 73.000, China department of physics Xianyang Normal University Xianyang 712000 China Institute of Modern physics Chinese Academy of Sciences Lanzhou 730000 China

The highly charged ion 40Ar16+ with the velocity (kinetic energy EK=150 keV, velocity V=8.5×105 m/s) smaller than Bohr velocity (VBohr=2.9×106 m/s) was found to hove impacts on the surfaces of metals Ni, Mo, Au and Al, and the Ar atomic infrared light lines and X-rays spectra were simultaneously measured. The experimental results show that the highly charged ion that captures electrons is neutralized, and the multiply-excited hollow atom forms. The hollow atom cascade decay radiates lights from infrared to X-ray spectrum. The intensity of infrared lights shows that the metallic work functions play an important role in the neutralization process of highly charged ions during their interaction with metallic surfaces, which verifies the classical over-the-barrier model.

关键词： infrared light lines X-ray neutralization highly charged ions

Superconductivity of small metal grains

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Science China(physics,Mechanics & Astronomy) 2005年第4期48卷 431-441页

作者： ZHENG Renrong1 CHEN Zhiqian2.& ZHU Shunquan1,3.1. department of physics, Shanghai {2. University, Shanghai 2.02.4, China {3., Southwest {2. University, Chongqing 400715, China 3. department of Computer and Electric Technology, Shanghai Business School, Shanghai 2.1400, China 1. department of physics Shanghai Normal University 200234 Shanghai China 2. department of physics Southwest Normal University 400715 Chongqing China 3. department of Computer and Electric Technology Shanghai Business School 201400 Shanghai China

The formulas of the energy gap and superconducting critical temperature appropriate for systems with both odd and even number of electrons are derived; the bases of the derivations are BCS theory and energy level statistics. Numerical results qualitatively agree with the experimental phenomena. i.e., the superconductivity of small metallic grains will first enhance then decrease to zero when the grain are getting smaller and smaller. The calculations indicate that the above phenomena happen in the metallic grains belonging to Gaussian Orthogonal Ensemble (GOE) and Gaussian Unitary ensemble (GUE) with zero spin; The superconductivity of small metallic grains in Gaussian Symplectic Ensemble (GSE) will monotonically decrease to zero with the decreasing of the grain size. The analyses suggest that the superconductivity enhancements come from pairing and the balance of the strengths between spin-orbital coupling and external magnetic field. In order to take the latter into account, it is necessary to include the level statistics given by Random Matrix Theory (RMT) in describing small metallic grains.

关键词： size effect, superconductivity enhancements, small metallic grains.

Kinetic energy and charge state effects in the X-ray emission of Mo surface induced by Xe^(q+)(q=2.,2.) ions

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Science China(physics,Mechanics & Astronomy) 2008年第9期51卷 1240-1244页

作者： CUI Ying1,YANG ShengSheng2.YANG ZhiHu3.XU JinZhang1,ZHANG HongQiang1,XU Xu1,SHAO JianXiong1,LIU ZhaoYuan1,XIAO GuoQing3.ZHANG XiaoAn4,ZHAO YongTao3.ZHANG YanPing3.& CHEN XiMeng1 1 department of Modern physics,Lanzhou University,Lanzhou 73.000,China 2.National Key Laboratory of Vacuum & Cryogenics Technology and physics,Lanzhou 73.000,China 3.Institute of Modern physics,Chinese Academy of Sciences,Lanzhou 73.000,China 4 normal College of xianyang,xianyang 713.00,China department of Modern physics Lanzhou University Lanzhou 730000 China National Key Laboratory of Vacuum & Cryogenics Technology and physics Lanzhou 730000 China Institute of Modern physics Chinese Academy of Sciences Lanzhou 730000 China normal College of xianyang Xianyang 713000 China

L-shell X-ray spectra of Mo surface induced by Xe2.+ and Xe2.+ were measured. The X-ray intensity was obtained in the kinetic energy range of the incident ions from 3.0 to 600 keV. The relationship of X-ray intensity ... 详细信息

关键词： X-ray surface kinetic energy and charge state effect Xeq+

Spectral anomalies and spectral switches of partially coherent and polychromatic light diffracted at an aperture

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Science China(physics,Mechanics & Astronomy) 2004年第1期47卷 24-35页

作者： Lü Baida1, 3.& PAN Liuzhan1, 2.1. Institute of Laser physics and Chemistry, Sichuan University, Chengdu 610064, China 2. department of physics, Luoyang {2. College, Luoyang 47102., China 3. State Key Laboratory of Laser Technology, Huazhong University of Science and Technology, Wuhan 43.074, China Correspondence should be addressed to L Baida (email: badalu@***) Received July 10, 2.03 1. Institute of Laser physics and Chemistry Sichuan University 610064 Chengdu China 2. State Key Laboratory of Laser Technology Huazhong University of Science and Technology 430074 Wuhan China 3. department of physics Luoyang Normal College 471022 Luoyang China

Based on the propagation theory of partially coherent light in the space-frequency domain, the anomalous spectral behavior and spectral switches in the far field of partially coherent and polychromatic light diffracted at an aperture are studied. It is shown that, as compared with spatially fully coherent and polychromatic light whose spectral anomalies are induced only by aperture diffraction, the spectral anomalies and spectral switches of partially coherent and polychromatic light depend on the aperture diffraction, spatial correlationβ and bandwidth of the original spectrum. Detailed numerical calculations are made to illustrate the behavior of spectral switches of partially coherent and polychromatic light, and the results for spatially fully coherent and polychromatic light are treated as a special case ofβ=1 and included in our theory.

关键词： spectral anomaly spectral switch partially coherent and polychromatic light far field aperture diffraction

Optimal reactions for the synthesis of superheavy nucleus ^(2.0)Hs

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Science China(physics,Mechanics & Astronomy) 2006年第6期49卷 641-648页

作者： LIU Zuhua1,3.& BAO Jingdong1,2.1. Key Laboratory of Beam Technology and Material Modification of Ministry of Education, Beijing normal University, Beijing 100875, China 2. {3. {2., Beijing normal University, Beijing 100875, China 3. China Institute of Atomic Energy, Beijing 102.13. China Key Laboratory of Beam Technology Material Modification of Ministry of Education Beijing Normal University Beijing 100875 China physics department Beijing Normal University Beijing 100875 China China Institute of Atomic Energy Beijing 102413 China

The superheavy nucleus 2.0Hs is expected to be a “double-magic” deformed nucleus. We have calculated its cross sections of evaporation residue for the reactions 2.8Cm(2.Mg,4n)2.0Hs, 2.4Pu(3.Si,4n)2.0Hs, 2.8U(3.S,4n)2.0Hs and 2.6Ra(48Ca,4n)2.0Hs using a two-parameter Smoluchowski equation. It is found from our results that 2.6Ra(48Ca,4n)2.0Hs and 2.8U(3.S,4n)2.0Hs are two optimal reactions for the synthesis of the superheavy nucleus 2.0Hs due to their large negative Q-values.

关键词： diffused fusion barrier,Smoluchowski equation,superheavy nuclei.

The optical near-field speckles and their first order statistics on the basis of the integral equations of electromagnetic field

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Science China(physics,Mechanics & Astronomy) 2004年第3期47卷 365-380页

作者： CHENG Chuanfu1, 2. SONG Hongsheng2. LIU Chunxiang2. REN Xiaorong2. ZHANG Ningyu3. TENG Shuyun1 & XU Zhizhan1 1. Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, P. O. Box 800-2.1, Shanghai 2.1800, China 2. department of physics, Shandong normal University, Jinan 2.0014, China 3. Shandong Institute of Architecture and Engineering, Jinan 2.0014, China 1. Shanghai Institute of Optics and Fine Mechanics Chinese Academy of Sciences P. O. Box 800-211 201800 Shanghai China 2. department of physics Shandong Normal University 250014 Jinan China 3. Shandong Institute of Architecture and Engineering 250014 Jinan China

From Helmholtz equation of the harmonic electromagnetic waves, the integral equations of the light field at the medium boundaries are obtained by use of the Green's theorem and are discretized into linear equation set with the values of the light field and its derivative as the unknowns. On solving the linear equation set, we realize the rigorous computations of the light fields at the boundaries. Then the intensities of the light waves scattered by the random self-affine fractal surfaces in the optical near-field are calculated, and the propagation characteristics, the evolutions of the contrast and the intensity probability density function of the near-field speckles are studied in detail. The near-field speckles are much different from the conventional speckles in the diffraction regions and in the imaging systems. There are obvious local fluctuations in the intensity distributions of the near-field speckles and such fluctuations disappear after propagating a distance of one wavelength from the medium surfaces. For the random surfaces with smaller lateral correlation lengths, the speckle contrasts approach the saturation values and the speckle fields approach Gaussian distribution within the near-field, while for the random surfaces with larger lateral correlation lengths, such evolutions become comparatively slow.

关键词： speckle, near-field optics, first order statistics, Green's function.

The influence of laser pulse on the photoabsorption spectra of Li atom in strong external field

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Science China(physics,Mechanics & Astronomy) 2006年第2期49卷 178-186页

作者： WANG Dehua1 & LIN Shenglu2.1. School of physics and Electronic Engineering, Yantai normal University, Yantai 2.402., China {2., Shandong normal University, Jinan 2.0014, China 1. School of physics and Electronic Engineering Yantai Normal University Yantai 264025 China 2. department of physics Shandong Normal University Jinan 250014 China

Using the time-dependent perturbation theory and the calculation formula of the single- and double-pulse absorption spectra of the atom in strong external fields, we calculate the single- and double-pulse absorption spectra of Li atom in strong magnetic field for different pulse widths. The results show that a pulse of some width can reduce the contribution of the short period closed orbits and eliminate the contribution of the long period orbits. Compared with the single-pulse absorption spectra, we found that for some phase differences, the double-pulse laser absorption spectra are strengthened; while for others, they are reduced. Therefore, we can use the pulse laser to control the oscillation of the absorption spectra and obtain the optimization object.

关键词： laser pulse closed orbit absorption spectra.