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41.
A core level and valence band photoemission study of thick 3C–SiC(1 1 1) and 3C–SiC(
) epilayers grown by sublimation epitaxy is reported. The as introduced samples show threefold 1×1 low-energy electron diffraction patterns. For the Si face
and
reconstructed surfaces develop after in situ heating to 1100°C and 1300°C, respectively. For the C face a 3×3 reconstruction form after heating to 980°C. A semiconducting behavior is observed for the
and 3×3 reconstructed surfaces while the
reconstruction show a Fermi edge and thus a metallic-like behavior. The surface state on the
surface is investigated and found to have Λ1 symmetry and a total band width of 0.10 eV within the first surface Brillouin zone. For the Si 2p and C 1s core levels binding energies and surface shifted components are extracted and compared to earlier reported results for 6H– and 4H–SiC. 相似文献
42.
Correlation between the O 2p Orbital and Redox Reaction in LiMn0.6Fe0.4PO4 Nanowires Studied by Soft X‐ray Absorption
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Dr. Daisuke Asakura Dr. Eiji Hosono Dr. Masashi Okubo Dr. Yusuke Nanba Dr. Haoshen Zhou Dr. Per‐Anders Glans Dr. Jinghua Guo 《Chemphyschem》2016,17(24):4110-4115
The changes in the electronic structure of LiMn0.6Fe0.4PO4 nanowires during discharge processes were investigated by using ex situ soft X‐ray absorption spectroscopy. The Fe L ‐edge X‐ray absorption spectrum attributes the potential plateau at 3.45 V versus Li/Li+ of the discharge curve to a reduction of Fe3+ to Fe2+. The Mn L ‐edge X‐ray absorption spectra exhibit the Mn2+ multiplet structure throughout the discharge process, and the crystal‐field splitting was slightly enhanced upon full discharge. The configuration‐interaction full‐multiplet calculation for the X‐ray absorption spectra reveals that the charge‐transfer effect from O 2p to Mn 3d orbitals should be considerably small, unlike that from the O 2p to Fe 3d orbitals. Instead, the O K‐edge X‐ray absorption spectrum shows a clear spectral change during the discharge process, suggesting that the hybridization of O 2p orbitals with Fe 3d orbitals contributes essentially to the reduction. 相似文献
43.
T. Schneller H. Kohlstedt A. Petraru R. Waser J. Guo J. Denlinger T. Learmonth Per-Anders Glans K. E. Smith 《Journal of Sol-Gel Science and Technology》2008,48(1-2):239-252
Chemical solution deposited (CSD) complex oxide thin films attract considerable interest in various emerging fields as for example, fuel cells, ferroelectric random access memories or coated conductors. In the present paper the results of soft-X-ray spectroscopy between 280 and 560 eV on the amorphous to crystalline phase transition of ferroelectric Pb(Zr0.3Ti0.7)O3 (PZT) thin films are presented. Five CSD samples derived from the same wafer coated with a PZT film pyrolyzed at 350 °C were heat treated at different temperatures between 400 and 700 °C. At first the samples were morphologically and electrically characterized. Subsequently the soft-X-ray absorption and emission experiments were performed at the undulator beamline 8.0 of the Advanced Light Source of the Lawrence Berkeley National Laboratory. Soft-X-ray absorption spectra were acquired for the Ti L 2,3-, O K-, and C K-edge thresholds by using simultaneously the total electron yield (TEY) and total fluorescence yield (TFY) detection methods. For two samples, annealed at 400 and 700 °C, respectively, the resonant inelastic soft-X-ray spectroscopy (RIXS) was applied for various excitation energies near the Ti L-, O K-edges. We observed clear evidence of a rutile phase at untypically low temperatures. This rutile phase transforms into the perovskite phase upon increasing annealing temperature. These results are discussed in the framework of current microscopic models of the PZT (111) texture selection. 相似文献
44.
Demortière A Launois P Goubet N Albouy PA Petit C 《The journal of physical chemistry. B》2008,112(46):14583-14592
Liquid-liquid phase transfer has been used to synthesize platinum nanocrystals with a cubic morphology. By finely tuning the parameters controlling the nucleation and growth processes, nanometric truncated cubes or perfect cubes may be obtained. To our knowledge, this is the first time such shapes are obtained with this procedure. The importance of both the length of the capping agent to control the growth process and the bromide anions as poison for the (111) facet is shown. The low degree of size polydispersity allows these nanocrystals to self-assemble with a long-range ordering in two-dimensional and three-dimensional supracrystals. According to the nanocrystal shape, simple cubic or face-centered cubic supracrystals are observed. It is remarkable to notice that well-faceted supracrystals with sizes on the order of 10 microm may be obtained. 相似文献
45.
Glans L Ehnbom A de Kock C Martínez A Estrada J Smith PJ Haukka M Sánchez-Delgado RA Nordlander E 《Dalton transactions (Cambridge, England : 2003)》2012,41(9):2764-2773
Three new ruthenium complexes with bidentate chloroquine analogue ligands, [Ru(η(6)-cym)(L(1))Cl]Cl (1, cym = p-cymene, L(1) = N-(2-((pyridin-2-yl)methylamino)ethyl)-7-chloroquinolin-4-amine), [Ru(η(6)-cym)(L(2))Cl]Cl (2, L(2) = N-(2-((1-methyl-1H-imidazol-2-yl)methylamino)ethyl)-7-chloroquinolin-4-amine) and [Ru(η(6)-cym)(L(3))Cl] (3, L(3) = N-(2-((2-hydroxyphenyl)methylimino)ethyl)-7-chloroquinolin-4-amine) have been synthesized and characterized. In addition, the X-ray crystal structure of 2 is reported. The antimalarial activity of complexes 1-3 and ligands L(1), L(2) and L(3), as well as the compound N-(2-(bis((pyridin-2-yl)methyl)amino)ethyl)-7-chloroquinolin-4-amine (L(4)), against chloroquine sensitive and chloroquine resistant Plasmodium falciparum malaria strains was evaluated. While 1 and 2 are less active than the corresponding ligands, 3 exhibits high antimalarial activity. The chloroquine analogue L(2) also shows good activity against both the chloroquine sensitive and the chloroquine resistant strains. Heme aggregation inhibition activity (HAIA) at an aqueous buffer/n-octanol interface (HAIR(50)) and lipophilicity (D, as measured by water/n-octanol distribution coefficients) have been measured for all ligands and metal complexes. A direct correlation between the D and HAIR(50) properties cannot be made because of the relative structural diversity of the complexes, but it may be noted that these properties are enhanced upon complexation of the inactive ligand L(3) to ruthenium, to give a metal complex (3) with promising antimalarial activity. 相似文献
46.
We show that the propagation of coherent acoustic phonons generated by femtosecond optical excitation can be clearly resolved using a probe laser in the middle UV (MUV) range. The MUV probe is easily produced from a high-repetition-rate femtosecond laser and a homemade frequency tripler. We present various experimental results that demonstrate efficient and high frequency detection of acoustic phonons. Thus, we show that the MUV range offers a unique way to reach higher frequencies and probe smaller objects in ultrafast acoustics. 相似文献
47.
A first temperature measurement of the expanded electron beam from a super-conducting magnet in the cooler of CRYRING is reported.
It is based on detection of a dielectronic recombination resonance in C2+. For this measurement C3+ was stored in the ring at 3 rm{MeV/amu} energy. A fit to the resonance with free transverse and longitudinal temperatures
gave 3.9 × 10-3 eV and 4.5 × 10-5 eV, respectively. The result is also compatible with the values of 10-3 eV for the transverse and 6.7 ×10-5 eV for the longitudinal component, in good agreement with expected values.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
48.
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50.
Xiaobo Chen Per-Anders Glans Xiaofeng Qiu Smita Dayal Wayne D. Jennings Kevin E. Smith Clemens Burda Jinghua Guo 《Journal of Electron Spectroscopy and Related Phenomena》2008
The electronic origins of the visible-light response of N-, C- and S-doped TiO2 have been studied using X-ray absorption, X-ray emission, and X-ray photoelectron spectroscopies. New electronic states are observed in the bulk band gap, above the valence band edge of pure TiO2, which can be directly related to the visible-light absorption of the N-, C- and S-doped TiO2 materials. 相似文献