243 research outputs found
Incoherent charge transport through molecular wires: interplay of Coulomb interaction and wire population
The influence of Coulomb interaction on the electron transport through
molecular wires is studied in the regime of incoherent tunneling. In the limit
of strong Coulomb repulsion, the current for spinless electrons is determined.
It is shown that the voltage profile along the wire crucially influences the
dependence of the current on the wire length. Upon inclusion of the spin degree
of freedom one finds a blocking effect which depends both on the interaction
strength and on the population of the wire. For finite Coulomb interaction, the
temperature dependence of the blocking is studied and it is shown that several
regimes with different blocking strength may exist.Comment: 18 pages, 8 figures, elsart.cls v2.18 include
Enhanced transmission through arrays of subwavelength holes in gold films coated by a finite dielectric layer
Enhanced transmissions through a gold film with arrays of subwavelength holes
are theoretically studied, employing the rigid full vectorial three dimensional
finite difference time domain method. Influence of air-holes shape to the
transmission is firstly studied, which confirms two different resonances
attributing to the enhanced transmission: the localized waveguide resonance and
periodic surface plasmon resonances. For the film coated with dielectric
layers, calculated results show that in the wavelength region of interest the
localized waveguide resonant mode attributes to sensing rather than the
periodic gold-glass surface plasmon mode. Although the detected peak is fairly
broad and the shift is not too pronounced, we emphasize the contribution for
sensing from the localized waveguide resonant mode, which may opens up new ways
to design surface plasmon based sensors.Comment: 11 pages including 4 figures. Accepted for JEOS:R
Performance and durability of solid oxide electrolysis cells for syngas production
Performance and durability of Ni/YSZ based solid oxide electrolysis cells (SOECs) for co-electrolysis of H2O and CO2 at high current density were investigated. The cells consist of a Ni/YSZ support, a Ni/YSZ fuel electrode, a YSZ electrolyte, and a LSM-YSZ oxygen electrode. The cell durability was examined at 800°C and electrolysis current density of -1 or -1.5 A/cm2 with 60% reactant (H2O+CO2) utilization. The cell voltage degradation showed a strong dependence on the electrolysis current density, with an overall cell voltage degradation rate of 0.24 mV/h at -1 A/cm2 and of 0.82 mV/h at -1.5 A/cm2. Electrochemical characterization of the cells showed that the degradation was mainly related to the LSM/YSZ electrode when operated at -1 A/cm2, whereas at increased current density (-1.5 A/cm2), both the Ni/YSZ and LSM/YSZ electrodes showed degradation.</jats:p
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