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- He, Sailing, et al.
(författare)
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Synchrotron radiation photoemission study of Yb2.75C60
- 2005
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Ingår i: Wuli xuebao. - : Acta Physica Sinica, Chinese Physical Society and Institute of Physics, Chinese Academy of Sciences. - 1000-3290. ; 54:3, s. 1400-1405
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Tidskriftsartikel (refereegranskat)abstract
- The Yb275C60 thin film was prepared and studied by using the synchrotron radiation ultraviolet photoemission spectroscopy(PES) in an ultrahighvacuum system. The spectral line obtained in the range between the Fermi level and ～5 eV binding energy consists of those lines from the valence band (the molecular orbital LUMO, HOMO and HOMO1 derived energy bands of C60) and core levels(Yb 4f7/2 and 4f5/2). Taking into account the variations of the photoinization cross sections of C 2p and Yb 4f with different photon energies, we have measured the photoemission spectra under the condition of varying photon energies, and carried out simulations to deduce the component contributions. The peak positions, widths and intensities for the components are obtained quantitatively. The results reveals that the photoemission of 4f electrons has a significant intensity with the photon energies larger than ～300 eV, and that the measured spectra depart drastically from the density of states of the valence band. To observe the valence band structure, one should carry out the PES measurements by using photons with energies less than 300 eV. The photoionization crosssection oscillation is also observed in Yb275C60 with almost the same oscillation period as that for pure C60 However, the oscillation amplitude is obviously smaller than that for pure C60, which reveals that the chemical environment of C60 in compounds has nonnegligible effects on the photoionization crosssection oscillation phenomenon.
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| 2. |
- Chen, Shuang, et al.
(författare)
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CH4/Air反扩散射流火焰多组分同步PLIF诊断
- 2018
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Ingår i: Shiyan Liuti Lixue/Journal of Experiments in Fluid Mechanics. - 1672-9897. ; 32:1, s. 26-32
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Tidskriftsartikel (refereegranskat)abstract
- The simultaneous multi-species Planar Laser Induced Fluorescence technique plays an important role in studying the flame structure and the two-dimensional distribution of intermediate species in combustion. The experimental system of OH/CH2O/Acetone-PLIF was built in order to study the CH4-Air inverse diffusion jet (IDJ) flame. The system consists of two sets of lasers, two intensifier-CCD cameras, a temporal controller and several lenses. The strategy of fluorescence excitation, the method of synchronous timing control and image calibration procedures are discussed. The IDJ flame was studied using the simultaneous multi-species PLIF technique, and the reaction zone, pre-heating zone and fuel zone of IDJ flame were determined. Experimental results suggest that the IDJ flame is different from either the normal diffusion flame or the premixed jet flame. The behavior of this type of flame reveals similarity to the partially premixed flame. Compared to OH chemilumiscence images, simultaneous multi-species PLIF can provide more detail and information about the flame structure and it has huge potential in fundamental combustion studies and industrial burner experiments
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