In this work, a beta -MnO sub(2)/polypyrrole ( beta -MnO sub(2)/PPy) composite was prepared by a facile solvothermal method. The conductivity of the polymer PPy deposited on the surface of MnO sub(2) ...can significantly improve the electronic conductivity and accommodate the volume change. Compared with pristine beta -MnO sub(2), beta -MnO sub(2)/PPy exhibited excellent cycling performance and superior rate capability when used as anode for lithium-ion batteries.
This letter presents a novel broadband microstrip patch antenna with a simple geometry. Two parasitic mushroom-type arrays are incorporated along with the two radiating edges of a main radiating ...patch. First, thanks to the mushroom-type structure, a new resonant mode, characterized as quasi-TM<inline-formula><tex-math notation="LaTeX">_{30}</tex-math></inline-formula> mode, is generated. Besides, the main radiating patch produces the original TM<inline-formula><tex-math notation="LaTeX">_{10}</tex-math></inline-formula> mode. Thus, wideband performance is realized on the basis of the two combined modes. Second, the current distributions on those metal patches are nearly uniform so that high gains are achieved over the entire operating bandwidth. Measured results indicate that the enhanced impedance bandwidth is from 11.9 to 18.2 GHz, which covers the whole Ku-band. Meanwhile, a nearly constant peak-radiating gain between 10 and 10.5 dBi at broadside radiation is obtained. The proposed antenna maintains the advantages of wide bandwidth, ease of fabrication, flat and high gains, and a low profile less than <inline-formula><tex-math notation="LaTeX">{\lambda _0}</tex-math></inline-formula>/13 thickness substrate.
Three kinds of porous organic polymers (POPs) with different topological structures, named CMP, HsGY and PAF, were prepared by Sonogashira–Hagihara cross-coupling reaction with three different ...monomers. POPs were characterized by field emission scanning electron microscope (FE-SEM), fourier transform infrared spectroscopy (FTIR), nitrogen absorption–desorption isotherm, etc. The characterization results indicated that three-dimensional structure and π electronic structure of monomers had a significant impact on the morphology and properties of POPs, and deep eutectic solvents (DES) was a simple and effective functionalization strategy. POPs had absorption in both the UV and visible light ranges. Among them, PAF had the widest visible light absorption edge, with an absorption edge of 627 nm (Eg = 1.98 eV). The carboxylation of DES improved the specific adsorption of POPs on fluoroquinolones. The most significant increase in adsorption capacity of carboxylated HsGY was observed. Its adsorption capacity for norfloxacin was 29.0 mg g
−1
, for ofloxacin was 28.4 mg g
−1
, and for ciprofloxacin was 29.1 mg g
−1
. POPs had double layer capacitance characteristics, and different monomers had a significant impact on the specific capacitance of POPs. DES amination could improve the specific capacitance of POPs. This work had promoted the development of POPs and provided reference for their applications in the fields of adsorbents and supercapacitors.
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•Broadband optical properties of graphene and HOPG are comparatively studied by MME.•Optical and dielectric models are constructed for the ellipsometric analysis.•Some intrinsic ...features of graphene and HOPG are observed and discussed.•Physical mechanisms of these intrinsic features are revealed and compared.
Optical properties of mono-graphene fabricated by chemical vapor deposition (CVD) and highly oriented pyrolytic graphite (HOPG) are comparatively studied by Mueller matrix ellipsometry (MME) over an ultra-wide energy range of 0.73–6.42 eV. A multilayer stacking model is constructed to describe the CVD mono-graphene, in which the roughness of the glass substrate and the water adsorption on the graphene are considered. We introduce a uniaxial anisotropic dielectric model to parameterize the optical constants of both the graphene and the HOPG. With the established models, broadband optical constants of the graphene and the HOPG are determined from the Mueller matrix spectra based on a point-by-point method and a non-linear regression method, respectively. Two significant absorption peaks at 4.75 eV and 6.31 eV are observed in the extinction coefficient spectra of the mono-graphene, which can be attributed to the von-Hove singularity (i.e., the π-to-π∗ exciton transition) near the M point and the σ-to-σ∗ exciton transition near the Γ point of the Brillouin zone, respectively. Comparatively, only a major absorption peak at 4.96 eV appears in the ordinary extinction coefficient spectra of the HOPG, which is mainly formed by the π-to-π∗ interband transition.
The conformation and physicochemical attributes of proteins play important roles in determining their flexibility. This study investigates the structural flexibility of twelve different soybean ...proteins. Results suggest that amino acids not only affects protein flexibility but its spatial structure as well. In addition, β-conglycinin protein contained more flexible subunits than glycinin. The HN-87, HN-48, HH-44 and HH-53 proteins were more flexible with lower α-helix content. Other key factors that influence higher structural flexibility include higher surface hydrophobicity and fewer disulfide bonds. Furthermore, more flexible proteins ensured the unfolding of the polypeptide chain backbone and endowed them with excellent emulsifying characteristics. In all, flexible proteins showed stronger surface activity than rigid ones. These findings thus provide clear evidence on the structural flexibility-functional properties interactions of different soybean proteins.
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•The protein with more β-conglycinin and fewer basic subunits had a higher structural flexibility.•Flexible protein with lower content of α-helix would unfold the polypeptide chain backbone easily.•Flexible proteins exhibited better emulsifying and foaming properties due to their higher surface hydrophobicity.
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