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B_u介子的纯细子衰变辐射修正
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作者 王俊年 王国利 娄慧佺 《中山大学学报论丛》 2002年第1期216-219,共4页
计算了Bu 介子纯轻子衰变有一辐射修正。给出了过程Bu→λυλγ的光子能量谱。
关键词 纯轻子衰变 辐射修正 光子能量谱 辐射衰变 Bu介子 纯细子衰变
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Theoretical Analysis of Gain and Threshold Current Density for Long Wavelength GaAs-Based Quantum-Dot Lasers'
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作者 邓盛凌 黄永箴 +1 位作者 金潮渊 于丽娟 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2005年第10期1898-1904,共7页
Quantum dot gain spectra based on harmonic oscillator model are calculated including and excluding excitons. The effects of non-equilibrium distributions are considered at low temperatures. The variations of threshold... Quantum dot gain spectra based on harmonic oscillator model are calculated including and excluding excitons. The effects of non-equilibrium distributions are considered at low temperatures. The variations of threshold current density in a wide temperature range are analyzed and the negative characteristic temperature and oscillatory characteristic temperature appearing in that temperature range are discussed. Also,the improvement of quantum dot lasers' performance is investigated through vertical stacking and p-type doping and the optimal dot density, which corresponds to minimal threshold current density,is calculated. 展开更多
关键词 quantum dot lasers multiple energy levels gain spectrum temperature dependence
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Structural and Bonding Properties of Al_(n)C_(4)^(−/0)(n=2−4)Clusters:Anion Photoelectron Spectroscopy and Theoretical Calculations
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作者 Chao-jiang Zhang Shuai-ting Yan +2 位作者 Hong-guang Xu Xi-ling Xu Wei-jun Zheng 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2021年第6期769-776,I0002,I0003,I0053-I0055,共13页
We measured the photoelectron spectra of Al_(n)C_(4)^(−)(n=2−4)clusters by using size-selected anion photoelectron spectroscopy.The structures of Al_(n)C_(4)^(−/0)(n=2−4)clusters were explored with quantum chemistry c... We measured the photoelectron spectra of Al_(n)C_(4)^(−)(n=2−4)clusters by using size-selected anion photoelectron spectroscopy.The structures of Al_(n)C_(4)^(−/0)(n=2−4)clusters were explored with quantum chemistry calculations and were determined by comparing the theoretical results with the experimental spectra.It is found that the most stable structure of Al_(2)C_(4)^(−) anion is a C_(2v)symmetry planar structure with two Al atoms interacting with two C_(2)units.In addition,Al_(2)C_(4)^(−) anion also has a D∞h symmetry linear structure with two Al atoms located at the two ends of a C_(4)chain,which is slightly higher in energy than the planar structure.The most stable structure of neutral Al_(2)C_(4)has a D∞h symmetry linear structure.The most stable structure of Al_(3)C_(4)^(−) anion is a planar structure with three Al atoms interacting with two C_(2)units.Whereas neutral Al_(3)C_(4)cluster has a C_(2v)symmetric V-shaped bent structure.The global minima structures of both Al_(4)C_(4)^(−) and neutral Al_(4)C_(4)are C_(2)h symmetry planar structures with four Al atoms interacting with the ends of two C_(2)units.Adaptive natural density partitioning analyses of Al_(n)C_(4)^(−)(n=2−4)clusters show that the interactions between the Al atoms and C_(2)units have bothσandπcharacters. 展开更多
关键词 Anion photoelectron spectroscopy Quantum chemistry calculations Planar aluminum-carbon structures
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Energy Spectrum, g Factors, Strain-Induced Level-Splittings and R-Line Thermal Shift of MgO:V^(2+)
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作者 ZHANG Zheng-Jie MA Dong-Ping 《Communications in Theoretical Physics》 SCIE CAS CSCD 2008年第8期511-516,共6页
Traditional ligand-field theory has to be improved by taking into account both pure electronic contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy). By means of improved... Traditional ligand-field theory has to be improved by taking into account both pure electronic contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy). By means of improved ligand-field theory, the R line, t^322T1 and t^322T2 lines, t^22(^3T1)e^4T2, t^22(^3T1)e^4T1 and t2e^2(^4A2)4T1 bands, g factors of t^32 ^4A2 and t32E, four strain-induced level-splittings and R-line thermal shift of MgO:V^2+ have been calculated. The results are in very good agreement with the experimental data. It is found that for MgO:V^2+, the contributions due to electronphonon interaction (EPI) come from the first-order term; the contributions from the second-order and higher terms are insignificant. In thermal shift of R line of MgO:V^2+, the temperature-dependent contribution due to EPI is dominant. The results obtained in this work may be used in theoretical calculations of other effects of EPI. 展开更多
关键词 improved ligand-field theory electron-phonon interaction energy spectrum strain-induced split-ting thermal shift g factor
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A Study of Confined Helium Atom
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作者 XIE Wen-Fang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2007年第2X期331-334,共4页
The helium atom confined by a spherical parabolic potential well is studied employing the adiabatic hyperspherical approach method. Total energies of the ground and three low-excited states are obtained as a function ... The helium atom confined by a spherical parabolic potential well is studied employing the adiabatic hyperspherical approach method. Total energies of the ground and three low-excited states are obtained as a function of the confined potential radii. We find that the energies of a spherical parabolic potential well are in good agreement with those of an impenetrable spherical box for the larger confined potential radius. We find also that the confinement may cause accidental degeneracies between levels with different low-excited states and the inversion of the energy values. The results for the three-dimensional spherical potential well and the two-dimensional disc-like potential well are compared with each other. We find that the energy difference between states in a two-dimensional parabolic potential is also obviously larger than the corresponding levels for a spherical parabolic potential. 展开更多
关键词 helium atom energy spectrum
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Three Charged Bosons Confined in a Harmonic Trap
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作者 XIE Wen-Fang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第3X期529-531,共3页
A system of three charged bosons confined in a harmonic trap has been investigated by an exact diagonalization. We report a calculation for the energy spectrum of the low-lying states of a system of three charged boso... A system of three charged bosons confined in a harmonic trap has been investigated by an exact diagonalization. We report a calculation for the energy spectrum of the low-lying states of a system of three charged bosons.The important feature of the low-lying states of three charged bosons in a harmonic trap is obtained via an analysis of the energy spectrum. 展开更多
关键词 BOSON energy spectrum
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Improved Ligand-Field Theory with Effect of Electron-Phonon Interaction 被引量:1
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作者 MADong-Ping CHENJu-Ron 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第3期529-538,共10页
Traditional ligand-field theory has to be improved by taking into account both 'pure electronic' contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy). By means of ... Traditional ligand-field theory has to be improved by taking into account both 'pure electronic' contribution and electron-phonon interaction one (including lattice-vibrational relaxation energy). By means of improved ligand-field theory, R1, R2, R'3, R'2, and R'1 lines, U band, ground-state zero-field-splitting (GSZFS), and ground-state g factors of ruby and/or GSGG: Cr3+ as well as thermal shifts of GSZFS, R1 line and R2 line of ruby have been calculated.The results are in very good agreement with the experimental data. Moreover, it is found that the value of cubic-field parameter given by traditional ligand-field theory is inappropriately large. For thermal shifts of GSZFS, R1 line and R2 line of ruby, several conclusions have also been obtained. 展开更多
关键词 improved ligand-field theory electron-phonon interaction Stokes shift energy spectrum thermal shift g factor
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Hard X-ray Photoelectron Spectroscopy Study of Electron Spectral Structure beyond the Known Signal Electron Peak
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作者 Alon Givon Eitan Tiferet +4 位作者 German R. Castro Juan Rubio-Zuazo Erez Golan Ilan Yaar ItzhakOrion 《Journal of Chemistry and Chemical Engineering》 2013年第7期601-605,共5页
HAXPES (hard X-ray photoelectron spectroscopy) is a powerful emerging instrument in surface analysis. It extended the photoelectron energy range up to 15,000 eV and opened the possibility to study much thicker films... HAXPES (hard X-ray photoelectron spectroscopy) is a powerful emerging instrument in surface analysis. It extended the photoelectron energy range up to 15,000 eV and opened the possibility to study much thicker films, buried layers and bulk electronic properties. In order to study these features, data for the electron IMFP (inelastic mean free path) at these energies is needed. To date, only calculated IMFP are available at energies above 5,000 eV and therefore experimental validation of these calculations are essential. In this paper, a new approach for using the HAXPES spectra is presented. This approach, treats the attenuated part of the electron spectrum as a whole to calculating the average electron energy loss. This average electron energy loss is the result of inelastic collisions in the material and hence, carry with it information about the electron transport poses. Carbon layers with thicknesses between 20 and 75 nanometer deposited over copper substrate were used to test this approach at the Spanish beam-line (Spline) in the ESRF (European synchrotron radiation facility). The measured results showed good agreement with the predictions of the multiple inelastic scattering theory. In addition, an algorithm for the experimental evaluation of electron IMFP, using the measured energy loss, is proposed. 展开更多
关键词 HAXPES IMFP carbon synchrotron.
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Direct View of Cr Atoms Doped in Anatase TiO2(001) Thin Film
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作者 唐浩奇 林岳 +2 位作者 程正旺 崔雪峰 王兵 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2018年第1期71-76,I0001,I0002,共8页
Imaging the doping elements is doped TiO2 thin film. But it is critical for understanding the photocatalytic activity of still a challenge to characterize the interactions between the dopants and the TiO2 lattice at t... Imaging the doping elements is doped TiO2 thin film. But it is critical for understanding the photocatalytic activity of still a challenge to characterize the interactions between the dopants and the TiO2 lattice at the atomic level. Here, we use high angle annular dark- field/annular bright-field scanning transmission electron microscope (HAADF/ABF-STEM) combined with electron energy loss spectroscopy (EELS) to directly image the individual Cr atoms doped in anatase TiO2(001) thin film from [100] direction. The Cr dopants, which are clearly imaged through the atomic-resolution EELS mappings while can not be seen by HADDF/ABF-STEM, occupy both the substitutional sites of Ti atoms and the interstitial sites of TiO2 matrix. Most of them preferentially locate at the substitutional sites of Ti atoms. These results provide the direct evidence for the doping structure of Cr-doped A- TiO2 thin film at the atomic level and also prove the EELS mapping is an excellent technique for characterizing the doped materials. 展开更多
关键词 Anatase Ti02 Cr dopants Scanning transmission electron microscope Elec-tron energy loss spectroscopy Pulsed laser deposition
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Trapped Three Interacting Bosons with a Short-Ranged Interaction
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作者 XIE Wen-Fang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第3X期538-540,共3页
A system of three bosons trapped by a parabolic confinement and interacting with a short-ranged interaction has been investigated by the exact diagonafization of the Hamiltonian matrix. We report a calculation for the... A system of three bosons trapped by a parabolic confinement and interacting with a short-ranged interaction has been investigated by the exact diagonafization of the Hamiltonian matrix. We report a calculation for the energy spectrum of the low-lying states of a system of three interacting bosons. The important feature of the low-lying states of three interacting bosons trapped by a parabolic confinement is obtained via an analysis of the energy spectrum. 展开更多
关键词 BOSON energy spectrum
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Inhibiting Effect of Ciprofloxacin,Norfloxacin and Ofloxacin on Corrosion of Mild Steel in Hydrochloric Acid 被引量:7
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作者 庞雪辉 冉祥滨 +2 位作者 匡飞 解建东 侯保荣 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2010年第2期337-345,共9页
The inhibiting effect of ciprofloxacin,norfloxacin and ofloxacin on the corrosion of mild steel in 1 mol·L-1 HCl and the mechanism were studied at different temperatures using mass loss measurement,electrochemica... The inhibiting effect of ciprofloxacin,norfloxacin and ofloxacin on the corrosion of mild steel in 1 mol·L-1 HCl and the mechanism were studied at different temperatures using mass loss measurement,electrochemical method,and X-ray photoelectron spectroscopy(XPS) .Effective inhibition was shown by mass loss,potentiodynamic polarization and impedance spectroscopy measurement.The corrosion rate of the metal in the mass loss measurement,and the corrosion reaction on cathode and anode in the electrochemical measurement were accelerated when temperature was increased.XPS results showed that the inhibitors adsorbed effectively on the metal surface. 展开更多
关键词 CORROSION INHIBITION electrochemical impedance spectroscopy potentiodynamic polarization X-ray photoelectron spectroscopy
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Improvement of Magnetic Field on Tribological Properties of Lubricating Oils with Zinc Butyloctyldithiophosphate 被引量:11
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作者 Jiang Zeqi Fang Jianhua +3 位作者 Chen Boshui Wu Jiang Wang Jiu Zheng Zhe 《China Petroleum Processing & Petrochemical Technology》 SCIE CAS 2016年第4期92-98,共7页
Tribological properties of 150 SN mineral oil and the oils doped with different contents of zinc butyloctyldithiophosphate(T202) under magnetic field or non-magnetic field were evaluated on a four-ball tribotester by ... Tribological properties of 150 SN mineral oil and the oils doped with different contents of zinc butyloctyldithiophosphate(T202) under magnetic field or non-magnetic field were evaluated on a four-ball tribotester by applying an external magnetic field around the friction region. Moreover, the morphology and the tribochemical characteristics of worn surfaces were examined by a scanning electron microscope(SEM) and an X-ray photoelectron spectrometer(XPS). Then the lubrication mechanisms were discussed. The tribological test results indicated that the wear scar diameters(WSDs) of steel balls lubricated by the T202-containing lubricating oils and the friction coefficients of the corresponding oil under magnetic field were smaller than those without magnetic affection. The worn surface lubricated with the T202-formulated oils in a magnetic field was smoother than that obtained under the normal condition. Furthermore, the results of XPS analysis indicated that tribochemical films on the surfaces lubricated with T202-doped oils were mainly composed of compounds such as FeSO_4, FeS and ZnS. The atomic concentrations of oxygen, sulfur, iron, zinc and phosphorus species identified in T202 under magnetic field were higher than those without magnetic impact. It can be inferred that the improved anti-wear and friction-reducing ability of T202-doped oils was attributed to the promoted tribochemical reactions and the modification of the worn surfaces induced by magnetic field. 展开更多
关键词 magnetic field zinc butyloctyldithiophosphate improvement lubrication
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Theoretical Studies of Energy Spectra and g Factors of Cr3+-Doped YAl3(BO3)4
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作者 ZHANG Ji-Ping CHEN Gang ZHOU Hua-Bin 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第6期1121-1125,共5页
With the strong-field scheme and trigonal bases, by diagonalizing the complete d^3 energy matrix in a trigonally distorted cubic-field, the energy spectra and wavefunctions of YAl3(BO3)4:Cr^3+ have been calculated... With the strong-field scheme and trigonal bases, by diagonalizing the complete d^3 energy matrix in a trigonally distorted cubic-field, the energy spectra and wavefunctions of YAl3(BO3)4:Cr^3+ have been calculated. The rates of change of levels with respect to various parameters and the contributions to levels from various parameters are calculated, and the physical origins of various levels or splittings have been clearly and quantitatively shown. By using the wavefunctions obtained from diagonalizing the complete energy matrix, the g factors of the ground state of YAl3 (BO3 )4;Cr^3+ have been evaluated. The calculated results are in good agreement with the optical-spectral and EPR experimental data. It is demonstrated that the bonding between Cr^3+ and ligands (O^2-) is ionic. 展开更多
关键词 crystal fields energy spectrum g factor electronic paramagnetic resonance
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Negative Trions Trapped by a Spherical Parabolic Quantum Dot
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作者 XIE Wen-Fang 《Communications in Theoretical Physics》 SCIE CAS CSCD 2006年第3期565-567,共3页
In this paper, a negatively charged exciton trapped by a spherical parabolic quantum dot has been investigated. The energy spectra of low-lying states are calculated by means of matrix diagonalization. The important f... In this paper, a negatively charged exciton trapped by a spherical parabolic quantum dot has been investigated. The energy spectra of low-lying states are calculated by means of matrix diagonalization. The important feature of the low-lying states of the negatively charged excitons in a spherical quantum dot is obtained via an analysis of the energy spectra. 展开更多
关键词 TRION quantum dot
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Reality of Energy Spectra in Multi-dimensional Hamiltonians Having Pseudo Hermiticity with Respect to the Exchange Operator
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作者 AsiriNanayakkara 《Communications in Theoretical Physics》 SCIE CAS CSCD 2005年第1期49-54,共6页
The pseudo Hermiticity with respect to the exchange operators of N-D complexHamiltonians is investigated. It is shown that if an N-D Hamiltonian is pseudo Hermitian and anyeigenfunction of it retains π_αT symmetry t... The pseudo Hermiticity with respect to the exchange operators of N-D complexHamiltonians is investigated. It is shown that if an N-D Hamiltonian is pseudo Hermitian and anyeigenfunction of it retains π_αT symmetry then the corresponding eigen value is real, where π_αis an exchange operator with respect to the permutation a of coordinates and T is the time reversaloperator. We construct a special class of N-D pseudo Hermitian Hamiltonians with respect to exchangeoperators from both N/2-D and N-D general complex Hamiltonians. Examples are presented forHamiltonians with πT symmetry (π : x reversible y, p_x reversible p_y) and the reality of thesesystems are investigated. 展开更多
关键词 PT symmetry exchange operator pseudo hermitian
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Laser-induced Fluorescence Excitation Spectrum of NiS in 15500-17200 cm^-1
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作者 Jun-feng Zhen Li Wang +2 位作者 Cheng-bing Qin Qun Zhang Yang Che 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2009年第6期668-672,J0002,I0003,共7页
The laser-induced fluorescence excitation spectrum of jet-cooled NiS molecule has been recorded in the energy range of 15500 17200 cm-1. Fifteen bands have been assigned as three transition progressions:[15.65]^3Ⅱ1... The laser-induced fluorescence excitation spectrum of jet-cooled NiS molecule has been recorded in the energy range of 15500 17200 cm-1. Fifteen bands have been assigned as three transition progressions:[15.65]^3Ⅱ1(v′=0-4)-X^3∑0^-(v″=0),[15.69]^3∑0^-(v′=0-4)-X^3∑0^-(v″=0),and [15.81]^3Ⅱ1(v′=0-4)-X^3∑0^-(v″=0).Spectroscopic constants for the three newly identified electronically excited states have been determined for the first time. In addition,the lifetimes for most observed vibronic bands have also been measured. 展开更多
关键词 NIS Laser-induced fluorescence spectrum DC discharge
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Bremsstrahlung Radiation of Fast Electrons in Long Air Gaps
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作者 Oreshkin Evgeny Chaikovsky Stanislav Oginov Alexander Shpakov Konstantin 《Journal of Energy and Power Engineering》 2012年第6期906-911,共6页
The results of an experiment on discharges in long atmospheric pressure air gaps at a pulsed voltage of amplitude up to 800 kV and risetime 150-200 ns are analyzed. In the experiment, a radiation pulse of photon ener... The results of an experiment on discharges in long atmospheric pressure air gaps at a pulsed voltage of amplitude up to 800 kV and risetime 150-200 ns are analyzed. In the experiment, a radiation pulse of photon energy 〉 5 keV and duration 10-20 ns has been detected. It has been shown that the x-ray pulse is due to the "runaway" of electrons from the head of an anode-directed streamer. The estimated maximum bremsstrahlung energy is about 5-10 keV. The presence of a maximum in the bremsstrahlung spectrum is due to that the photons emitted by electrons are absorbed by atoms of the gas in which the discharge operates. 展开更多
关键词 Bremsstrahlung radiation processes of gas breakdown in electric fields STREAMER runaway electrons.
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Ab initio Study on Ionization Energies of 1-Methyl-hypoxanthine
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作者 Ke-dong Wang Da-peng Yang Yu-fang Liu 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2012年第5期540-544,I0003,共6页
Six low-lying tautomers of 1-methyl-hypoxanthine have been studied at the B3LYP/aug-cc- pVDZ level. Two tautomers NTH and N9H with the comparable energies are far more stable than the others. The vertical ionization e... Six low-lying tautomers of 1-methyl-hypoxanthine have been studied at the B3LYP/aug-cc- pVDZ level. Two tautomers NTH and N9H with the comparable energies are far more stable than the others. The vertical ionization energies of the tautomers calculated with ab initio electron propagator theory in the P3/aug-cc-pVDZ approximation are in agreement with the experimental data from photoelectron spectroscopy. According to the calculated relative energies and the comparison between the simulated and the experimental photoelectron spectra, it demonstrates that there are at least two tautomers of 1-methyl-hypoxanthine in the gas-phase experiments. 展开更多
关键词 TAUTOMER Ionization energy Relative energy Photoelectron spectrum
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What makes the Tc of monolayer FeSe on SrTiO3 so high: a sign-problem-free quantum Monte Carlo study 被引量:4
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作者 Zi-Xiang Li Fa Wang +1 位作者 Hong Yao Dung-Hai Lee 《Science Bulletin》 SCIE EI CAS CSCD 2016年第12期925-930,共6页
Monolayer FeSe films grown on SrTiO_3(STO)substrate show superconducting gap-opening temperatures(T_c) which are almost an order of magnitude higher than those of the bulk FeSe and are highest among all known Fe-based... Monolayer FeSe films grown on SrTiO_3(STO)substrate show superconducting gap-opening temperatures(T_c) which are almost an order of magnitude higher than those of the bulk FeSe and are highest among all known Fe-based superconductors. Angle-resolved photoemission spectroscopy observed ‘‘replica bands' ' suggesting the importance of the interaction between FeSe electrons and STO phonons. These facts rejuvenated the quest for T_c enhancement mechanisms in iron-based, especially ironchalcogenide, superconductors. Here, we perform the first numerically-exact sign-problem-free quantum Monte Carlo simulations to iron-based superconductors. We(1) study the electronic pairing mechanism intrinsic to heavily electron doped FeSe films, and(2) examine the effects of electron–phonon interaction between FeSe and STO as well as nematic fluctuations on T_c. Armed with these results, we return to the question ‘‘what makes the Tcof monolayer FeSe on SrTiO_3 so high?'' in the conclusion and discussions. 展开更多
关键词 High temperature superconductivity Pairing mechanism Iron-based superconductivity FeSe/STO Sign-problem-free quantum Monte-Carlosimulation
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Electrical and Raman properties of p-type and n-type modified graphene by inorganic quantum dot and organic molecule modification 被引量:4
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作者 HOU YanXue GENG XiuMei +3 位作者 LI YuanZuo DONG Bin LIU LiWei SUN MengTao 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2011年第3期416-419,共4页
We obtained n-type and p-type modified graphene by mixing quantum dots and depositing electron-acceptor molecules on the surface of graphene, respectively. The electrical and optical properties of these two types of s... We obtained n-type and p-type modified graphene by mixing quantum dots and depositing electron-acceptor molecules on the surface of graphene, respectively. The electrical and optical properties of these two types of samples were measured. For n-type modified graphene, the electrons were transferred from quantum dots to graphene. The resistance of these quantum dots in modified n-type graphene is significantly smaller than that of pristine graphene. For p-type graphene, modified by electron-acceptor organic molecules of tetracyanoethylene (TCNE), electrons were transferred from graphene to TCNE molecules. The resistance of this molecular modified p-type graphene is about 10% larger than that of pristine graphene. The charge transfer effect on the optical properties of graphene was investigated with Raman spectra. 展开更多
关键词 p-type and n-type graphene electrical property Raman property
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