Reconfigurable intelligent surfaces (RISs) have the potential to improve wireless communication links by dynamically redirecting signals to dead spots. Although a reconfigurable surface is best ...suited for environments in which the reflected signal must be dynamically steered, there are cases where a static, non-reconfigurable anomalous reflective metasurface can suffice. In this work, spray-coated liquid metal is used to rapidly prototype an anomalous reflective metasurface. Using a pressurized air gun and a plastic thin-film mask, a metasurface consisting of a 6 × 4 array of Galinstan liquid-metal elements is sprayed within minutes. The metasurface produces a reflected wave at an angle of 28° from normal in response to a normal incident 3.5-GHz electromagnetic plane wave. The spray-coated liquid-metal metasurface shows comparable results to an anomalous reflective metasurface with copper elements of the same dimensions, demonstrating that this liquid-metal fabrication process is a viable solution for the rapid prototyping of anomalous reflective metasurfaces.
We report 75As NMR experiments in heavily electron-doped LaFePnO0.75H0.25 (Pn=As1−xSbx and As1−x′Px′) compounds with the maximum Tcmax(∼33.1K), and compare with the previous results in lightly ...electron-doped LaFePn(O,F) compounds. The Tc of this series can be sensitively controlled by the pnictogen height (hPn) through the substitution at Pn site, and the electron doping level through the substitution at the O site with H or F. In heavily electron-doped LaFePnO(La1111) compounds, we found that spin fluctuations at low-energies were moderately suppressed upon cooling in the Sb-substituted high Tc compounds with high hPn (x ≥ 0), although they are completely suppressed in P-substituted non-superconducting compounds (x′ ≥ 0.2) with lower hPn. This feature is largely different from that in the lightly doped La1111 compounds with the well-nested Fermi surfaces, where the spin fluctuations are critically enhanced upon cooling. Here, we present the characteristics of spin fluctuations over wide doping region of La1111-based compounds, and discuss the relationship with the superconductivity.
Abstract
We report NMR experiments on heavily electron-doped Fe-based superconductor in comparison with the results on the parent Fe-based compounds. The typical parent Fe-based compound LaFe(As
1-
x
...′
P
x
′
)O exhibits the re-emergent antiferromagnetic (AFM) order at
x
′ ~ 0.6 (AFM2) separated from the parent AFM order at
x
′ =0 (AFM1). Systematic
31
P-NMR study on Sr
4
Sc
2
O
6
Fe
2
(As
1−
x
P
x
)
2
(SrSc42622), which has local lattice parameters of iron-pnictogen (Fe
Pn
) layer similar to the series of LaFe(As
1−
x
′
/P
x
′
)O, also revealed that the presence of AFM1 order is universal for most of parent Fe-based compounds. In contrast, the static AFM2 order was absent in this series, however, the dynamical low-energy AFM spin fluctuations are enhanced at around
x
~ 0.8, indicating that the onset of the static AFM2 is quite sensitive to the local lattice parameters of Fe
Pn
layer. In order to elucidate the further universality and diversity, we have carried out
77
Se-NMR measurement on Li
x
(NH
3
)
y
Fe
2−
δ
Se
2
(
T
c
= 44 K) in heavily electron-doped regime. Although the spin fluctuations at low energies does not significantly develops upon cooling, the moderate spin fluctuations were extracted at high temperatures from comparison of the temperature (
T
) dependences of Knight shift and nuclear relaxation rate (1/
T
1
T
). We discuss the universality and diversity of the relationship between the
T
c
and the characteristics of the spin fluctuations in the Fe-based compounds from a microscopic point of the NMR measurements.
Background and Objective: The purpose of this study was to investigate the effects of cranberry polyphenol fraction on biofilm formation and activities of Arg‐gingipain and Lys‐gingipain in ...Porphyromonas gingivalis.
Material and Methods: The polyphenol fraction was prepared by using a glass column packed with Amberlite XAD 7HP and 70% aqueous ethanol as an elution solvent.
Results: Synergistic biofilm formation by P. gingivalis and Fusobacterium nucleatum was significantly inhibited by the polyphenol fraction at a concentration of 250 µg/mL compared with untreated controls (p < 0.01). Arg‐gingipain and Lys‐gingipain activities in P. gingivalis ATCC 33277 and FDC 381 were inhibited significantly at a polyphenol fraction concentration of ≥ 1 µg/mL (p < 0.05).
Conclusion: These findings indicate that the polyphenol fraction inhibits biofilm formation and the Arg‐gingipain and Lys‐gingipain activities of P. gingivalis.
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