92 research outputs found
Research Issues, Challenges, and Opportunities of Wireless Power Transfer-Aided Full-Duplex Relay Systems
We present a comprehensive review for wireless power transfer (WPT)-aided full-duplex (FD) relay systems. Two critical challenges in implementing WPT-aided FD relay systems are presented, that is, pseudo FD realization and high power consumption. Existing time-splitting or power-splitting structure based-WPT-aided FD relay systems can only realize FD operation in one of the time slots or only forward part of the received signal to the destination, belonging to pseudo FD realization. Besides, self-interference is treated as noise and self-interference cancellation (SIC) operation incurs high power consumption at the FD relay node. To this end, a promising solution is outlined to address the two challenges, which realizes consecutive FD realization at all times and forwards all the desired signal to the destination for decoding. Also, active SIC, that is, analog/digital cancellation, is not required by the proposed solution, which effectively reduces the circuit complexity and releases high power consumption at the FD relay node. Specific classifications and performance metrics of WPT-aided FD relay systems are summarized. Some future research is also envisaged for WPT-aided FD systems
Correlation between intercalated magnetic layers and superconductivity in pressurized EuFe2(As0.81P0.19)2
We report comprehensive high pressure studies on correlation between
intercalated magnetic layers and superconductivity in EuFe2(As0.81P0.19)2
single crystal through in-situ high pressure resistance, specific heat, X-ray
diffraction and X-ray absorption measurements. We find that an unconfirmed
magnetic order of the intercalated layers coexists with superconductivity in a
narrow pressure range 0-0.5GPa, and then it converts to a ferromagnetic (FM)
order at pressure above 0.5 GPa, where its superconductivity is absent. The
obtained temperature-pressure phase diagram clearly demonstrates that the
unconfirmed magnetic order can emerge from the superconducting state. In stark
contrast, the superconductivity cannot develop from the FM state that is
evolved from the unconfirmed magnetic state. High pressure X-ray absorption
(XAS) measurements reveal that the pressure-induced enhancement of Eu's mean
valence plays an important role in suppressing the superconductivity and tuning
the transition from the unconfirmed magnetic state to a FM state. The unusual
interplay among valence state of Eu ions, magnetism and superconductivity under
pressure may shed new light on understanding the role of the intercalated
magnetic layers in Fe-based superconductors
Fermi Surface and Band Renormalization in (Sr,K)FeAs Superconductor from Angle-Resolved Photoemission Spectroscopy
High resolution angle-resolved photoemission measurements have been carried
out on (Sr,K)FeAs superconductor (Tc=21 K). Three hole-like Fermi
surface sheets are clearly resolved for the first time around the Gamma point.
The overall electronic structure shows significant difference from the band
structure calculations. Qualitative agreement between the measured and
calculated band structure is realized by assuming a chemical potential shift of
-0.2 eV. The obvious band renormalization suggests the importance of electron
correlation in understanding the electronic structure of the Fe-based
compounds.Comment: 4 pages, 4 figure
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