张鹏举
,
马新文
,
闫顺成
,
许慎跃
,
张少峰
,
朱小龙
,
刘惠萍
原子核物理评论
利用冷靶反冲离子动量谱仪,对电子轰击Ne原子的单电离反应(e,2e)进行了研究,实验测量了70-3300 eV入射能量情况下,反应过程中产生的一价反冲离子的动量分布,并对反冲离子的总动量进行了还原.介绍了一个简单的碰撞机制,据此着重分析了反冲离子纵向动量和横向动量二维谱形成的原因,该碰撞机制能够较好地解释较高能量入射时的实验结果.最后根据反冲离子的动量,估算了出射电子的能量范围,为下一步进行电子、离子的符合测量奠定了基础.
关键词:
反冲离子
,
单电离反应
,
冷靶反冲离子动量谱仪
,
动量分布
Communications in Theoretical Physics
By using the wavefunctions obtained from diagonalizing the complete d(3) energy matrix at normal and various pressures, the g factor of the ground state of SrTiO3:Cr3+ and its pressure-induced shift have been microscopically calculated. Only by taking the local strains around Cr3+ in SrTiO3:Cr3+ (which are about twice the bulk ones) and corresponding P-chi dependence, can we obtain a good agreement between the calculated result of pressure-induced shift of ground-state g factor and the experimental one. The physical origins of this pressure-induced shift have been explained. It is found that the change of Dq(-1) with pressure makes main contribution to the pressure-induced shift of ground-state g factor of SrTiO3:Cr3+. By using the wavefunctions obtained from diagonalizing the complete d3 energy matrix at normal pressure, the relevant matrix elements and accordingly strain-induced splittings of t(2)(3) E-2 and t(2)(3) (4)A(2) of SrTiO3:Cr3+ have been calculated. The important results of Y-c, Z(c), P-c and Q(c) have also been evaluated. It is the admixtures of basic wavefunctions resulted from the spin-orbit interaction and/or Coulomb interaction and/or Kramers degeneracy that make the strain-induced splittings of the levels nonzero. It is found that there are nonvanishing matrix elements of operators T2 xi, T2 eta and T2 zeta between wavefunctions with positive M-s and those with negative M-s', which have important effects on the strain-induced splittings of the levels.
关键词:
crystal fields;energy spectrum;g factors;high-pressure effect;strain-induced splitting;theoretical calculations;ruby;crystal
Yunxia GUO
,
Jie LIU
,
Jieying LIANG
,
null
材料科学技术（英文）
Surface of polyacrylonitrile (PAN)-based carbon fibers was modified by electrochemical oxidation. The modification effect on carbon fibers surface was explored using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). Results showed that on the modified surface of carbon fibers, the carbon contents decreased by 9.7% and the oxygen and nitrogen contents increased by 53.8% and 7.5 times, respectively. The surface roughness and the hydroxyl and carbonyl contents also increased. The surface orientation index was reduced by 1.5% which decreased tensile strength of carbon fibers by 8.1%, and the microcrystalline dimension also decreased which increased the active sites of carbon fiber surface by 78%. The physical and chemical properties of carbon fibers surface were modified through the electrochemical oxidative method, which improved the cohesiveness between the fibers and resin matrix and increased the interlaminar shear strength (ILSS) of carbon fibers reinforced epoxy composite (CFRP) over 20%.
关键词:
Polyacrylonitrile (PAN)
,
null
,
null
,
null
Communications in Theoretical Physics
By using the theory of pressure-induced shifts and the eigenfunctions at normal and various pressures obtained from the diagonalization of the complete d(3) energy matrix adopting C-3v symmetry, g factors of the ground state of ruby and their pressure-induced shifts have been calculated. The results are in very good agreement with the experimental data. For the precise calculation of properties of the ground state, it is necessary to take into account the effects of all the excited states by the diagonalization of the complete energy matrix.
关键词:
crystal fields;g factors;ruby;high-pressure effects
WANG Xike SHEN Ningfu CHEN Haisong Zhengzhou Institute of Technology
,
Zhengzhou
,
ChinaZHANG Haifeng Luoyang Research Institute for Ship Materials
,
Luoyang
,
ChinaGU Haicheng Xi'an Jiaotong University
,
Xi'an
,
China Professor
,
Research Centre for Materials
,
Zhengzhou Institute of Technology
,
Zhengzhou 450002
,
China
金属学报(英文版)
The depth profile of composition,chemical state of elements and morphology of as- received and activated amorphous Fe_(80)Zr_(12)B_8 alloy ribbons have been studied by means of Auger electron spectroscopy,X-ray photoelectron spectroscopy and scanning Auger microprobe combined with Ar ion bombardment.Both dull and free sides of the as- received ribbons were covered with an iron oxide layer.While a pronounced surface segregation and oxidation of B and precipitation of microcrystalline α-Fe particles were observed on both sides of activated ribbons,B and Zr were oxidized selectively in subsurface layer.On both sides of ribbons,a porous surface structure formed. The BET surface area was measured to be increasing from 0.11 to 2.68 m~2/g.The principal mechanism of in situ activation has been discussed.
关键词:
amorphous Fe_(80)Zr_(12)B8 alloy
,
null
,
null
,
null
Applied Surface Science
The surface state of Fe50Pd50 alloy ultrafine particles (UFP) has been investigated by AES and XPS. The results show that the surface of Fe50Pd50 alloy UFP was oxidized. There are two kinds of oxidized Fe existing on the surface of Fe50Pd50 alloy UFP. But the element Pd in the alloy UFP was not oxidized and stabilized the UFP. The surface of the alloy UFP is a bilayered structure.
关键词:
magnetic-properties;iron particles;spectroscopy;mossbauer
Physica Status Solidi B-Basic Research
The spin Hamiltonian parameters, g factors and the hyperfine structure constants for Co4+ (3d(5)) and Ir4+ (5d(5)) in SrTiO3 are theoretically studied from the formulas of these parameters for an nd(5) (n = 3 and 5) ion in a tetragonally distorted octahedron with low spin S = 1/2. According to the theoretical analyses, the impurity-ligand bond lengths R-parallel to' parallel to the C-4 axis are found to be larger than the host values R-parallel to based on the phase transition rotation angles phi of the [TiO6](8-) octahedron by the C-4 axis at 4.2 and 77 K, respectively. The elongation of the ligand octahedra in the host may be enhanced in the impurity centers by the Jahn-Teller effect of the nd(5) ions. The theoretical results based on the above local structures show good agreement with the experimental data.
关键词:
electron-paramagnetic-resonance;atomic screening constants;phase-transition;optical-absorption;scf functions;doped srtio3;degrees k;crystals;ions;spectra
Runhua Qin
材料科学技术（英文）
A novel salt-assisted low temperature solid state method using CoCl2?6H2O, FeCl3?6H2O and NaOH as pre-
cursor and using NaCl as a dispersant to synthesize high surface area CoFe2O4 nanoparticles, has been
investigated. The effects of the molar ratio of added salt and calcination temperature on the characteristics of
the products were investigated by X-ray diffraction (XRD), transmission electron microscopy (TEM), vibrating
sample magnetometer (VSM) and Brunauer, Emmett and Teller (BET) surface area analysis. Results showed
that the introduction of leachable inert inorganic salt as a hard agglomeration inhibitor in the mixture precursor
led to the formation of high dispersive CoFe2O4 nanoparticles; and the increase in specific surface area from
28.28 to 73.97 m2/g, and the saturation magnetization is 84.6 emu/g.
关键词:
Low temperature solid state reaction
,
盐助
,
钴铁氧体
,
纳米粒子
