Narrow Results

In this study, different percentages of semiconducting zinc oxide nanoparticles (ZnONPs) are mixed with polyvinyl alcohol (PVA) to create flexible ZnO/PVA polymer nanocomposite films. The characteristics of the prepared films are investigated using differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The XRD pattern shows that the ZnO/PVA composite films were successfully synthesized; while the SEM images show that the ZnONPs are homogeneously dispersed in the PVA polymer chain. Moreover, the DSC indicates an improvement in the thermal stability behavior with increased of ZnONPs concentration. The electrical conductivity, dielectric properties, electric modulus behavior, and the energy density efficiency of the pristine PVA and ZnO/PVA composite films are determined using an LCR meter in the frequency range 10²–10⁶ Hz. The dielectric constant of the composite film increased from 0.185 for pristine PVA to 1.389 for 9%ZnO/PVA, and the conductivity is improved from $1.93\times 10^{-5}$ S/cm to $7.98\times 10^{-5}$ S/cm. This work would open the road for utilizing ZnO/PVA flexible nanocomposite films for wide range of applications such as batteries, super-capacitor and energy storage devices.

In this study, ion-beam-sputtering technique is used to prepare nanocomposite films, consisting of deposited copper nanoparticles (CuNPs) on polyethyleneterephthalate (PET). The successful formation of the flexible Cu/PET composite films is confirmed by X-ray diffraction (XRD). The surface morphology of Cu/PET is studied by atomic force microscopy (AFM). The results show that the surface roughness increased from 22.6 nm for PET to 45.3 nm after 40 min of deposited Cu/PET. The sheet resistance decreases from $5.16\times 10^4\mathrm{\Omega }$ to $1.3\times 10^4\mathrm{\Omega }$ and resistivity decreases from $2.3\times 10^{-2}\mathrm{\Omega }\cdot \mathrm{\text{cm}}$ to $1.77\times 10^{-2}\mathrm{\Omega }\cdot \mathrm{\text{cm}}$, as the Cu deposition time increases from 20 min to 60 min. Moreover, Young’s modulus increases from 2.82 GPa to 2.96 GPa and the adhesion force enhances from 14.7 nN to 29.90 nN after 40 min of Cu deposition. The DC electrical conductivity at 300 V is improved from $1.75\times 10^{-8}$ S.cm${}^{-1}$ to $3.57\times 10^{-8}$ S.cm${}^{-1}$ after 60 min of Cu deposition. The results show the deposited Cu on flexible PET platform clearly exhibits improvement over pristine PET in the mechanical and electrical properties which render it useful for a broad range of dielectric applications.

Structural characteristics of O—H⋯O hydrogen bonds in inorganic crystals were comprehensively investigated on the basis of a database study. It is shown that the multi-furcated hydrogen bonds are very common, therefore, the structures of hydrogen bonds in inorganic crystals are extremely flexible. The direction and distance preferences of hydrogen bonds were systematically analyzed through frequency distribution histograms and normalized spatial frequency distribution scatter plot. In addition, new bond valence parameters were proposed for O—H⋯O bonds in inorganic crystals fully taking into account the multi-furcated hydrogen bonds, which can be used to properly evaluate hydrogen bond strengths in inorganic crystals. The current work sheds some light on the usage of hydrogen bonds in inorganic crystal design.

In this paper, by using the theory of local fractional calculus and some techniques of real analysis, the structural characteristics of Hilbert-type local fractional integral inequalities with abstract homogeneous kernel are studied. At the same time, the necessary and sufficient conditions for these inequalities to take the best constant factor are discussed. As an application, some best constant factor inequalities with specific kernels are obtained.

In the framework of the macroscopic optical model and semi-microscopic folding model, the authors have carried out a joint analysis of the experimental data (angular scattering distributions and total reaction cross sections) for the interaction of ⁶He- ions with ⁹Be- nuclei at energies from 1.37 to 25 MeV/A. The energy dependences of the total cross sections for reactions at low energies have been obtained and the radii of interaction of ⁶He nuclei have been determined.