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With the rapid development of electronic technique, wearable energy conversion and storage devices are facing huge challenges. Particularly, fiber supercapacitors have advantages of small size, light weight, high flexibility, fast charge/discharge process, high power density, long cycle life and wide operating temperature, showing considerable application prospect in the smart wearable field. This work proposes a strategy to fabricate MnO 2 , MnO 2 /PANI and MnO 2 /GN fiber electrodes via coaxial wet spinning technology, in which the electrochemical active materials could be wrapped into CMC layer perfectly, ensuring the structure stability of fiber electrodes effectively. And a series of MnO 2 -based parallel fiber supercapacitors are further assembled. After optimization of mixing ratios, the MnO 2 /PANI fiber supercapacitor with mixing-ratio of 1:1 exhibits specific capacitance of 0.68 μF·cm−1 at 0.25 μA·cm−1, and the MnO 2 /GN fiber supercapacitor with mixing-ratio of 9:1 presents 1.23 μF·cm−1at the same current density, which are both higher than that of pure MnO 2 fiber supercapacitor (0.59 μF·cm−1), proving significant enhancement of electrochemical performance due to the introduced PANI or GN. Therefore, this work provides a reliable guidance for design and application of wearable fiber supercapacitors. [Display omitted] • A facile strategy to fabricate MnO 2 , MnO 2 /PANI and MnO 2 /GN fiber supercapacitors. • PANI and graphene would enhance the electrochemical performance of MnO 2 devices. • MnO 2 /PANI fiber supercapacitor with mixing-ratio of 1:1 shows optimal performance. • MnO 2 /GN fiber supercapacitor with mixing-ratio of 9:1 exhibits optimal performance. [ABSTRACT FROM AUTHOR]

With the rapid development of electronic technique, wearable energy conversion and storage devices are facing huge challenges. Particularly, fiber supercapacitors have advantages of small size, light weight, high flexibility, fast charge/discharge process, high power density, long cycle life and wide operating temperature, showing considerable application prospect in the smart wearable field. This work proposes a strategy to fabricate MnO 2 , MnO 2 /PANI and MnO 2 /GN fiber electrodes via coaxial wet spinning technology, in which the electrochemical active materials could be wrapped into CMC layer perfectly, ensuring the structure stability of fiber electrodes effectively. And a series of MnO 2 -based parallel fiber supercapacitors are further assembled. After optimization of mixing ratios, the MnO 2 /PANI fiber supercapacitor with mixing-ratio of 1:1 exhibits specific capacitance of 0.68 μF·cm−1 at 0.25 μA·cm−1, and the MnO 2 /GN fiber supercapacitor with mixing-ratio of 9:1 presents 1.23 μF·cm−1at the same current density, which are both higher than that of pure MnO 2 fiber supercapacitor (0.59 μF·cm−1), proving significant enhancement of electrochemical performance due to the introduced PANI or GN. Therefore, this work provides a reliable guidance for design and application of wearable fiber supercapacitors. [Display omitted] • A facile strategy to fabricate MnO 2 , MnO 2 /PANI and MnO 2 /GN fiber supercapacitors. • PANI and graphene would enhance the electrochemical performance of MnO 2 devices. • MnO 2 /PANI fiber supercapacitor with mixing-ratio of 1:1 shows optimal performance. • MnO 2 /GN fiber supercapacitor with mixing-ratio of 9:1 exhibits optimal performance. [ABSTRACT FROM AUTHOR]

Abstract: The structural and magnetic properties of the Nd2Co7−x Fe x compounds related to R m+n T2m+5n series (R=rare earth, T=transition metal) were investigated by means of X-ray diffraction and magnetic measurements. The compounds crystallize in the Ce2Ni7-type structure with the space group P63/mmc between x =0.0 and 2.1. For higher Fe content the Nd2(CoFe)7 either coexists with the Nd(CoFe)3 phase (x >2.1) or decomposes to Nd(CoFe)3 +Nd2(CoFe)17 (x >2.4). The single phase Nd2Co7−x Fe x compounds exhibit two spin-reorientation transitions (SRT) for x <1.5. The substitution of Fe for Co elevates both the spin-reorientation transition temperatures for x <1.5 and finally leads to a single ferromagnetism to paramagnetism transition for x ≥1.5. A magnetic phase diagram is constructed based on the magnetic measurements, thermogravimetry analysis under a low magnetic field and X-ray diffraction of magnetically aligned samples. The saturation magnetization of the compounds increases gradually first with the Fe content for x ≤0.20, substantially for 0.20< x <1.5, and then decreases for x >1.5, which can be elucidated by a depletion effect of d band electrons due to the substitution of Fe for Co and the spin-flipping due to an enhanced d band splitting. [Copyright &y& Elsevier]

Single crystalline β -Ga 2 O 3 nanowires with different Zn doping contents were grown via catalytic chemical vapor deposition method. The field-emission scanning electron microscopy showed that when the Zn content was 1.3%, the Zn doped β -Ga 2 O 3 nanowires with uniform size and high density were synthesized. The diameter and length of nanowires were about 50 nm and dozens of micron, respectively. The X-ray diffraction measurements indicated that the position of (202) diffraction peak of samples shifted toward lower diffracting angle with increasing Zn content, which was explained by the substitution of Ga 3+ by Zn 2+ during Zn doping process. Furthermore, the Zn-doped β -Ga 2 O 3 nanowires/n-type β -Ga 2 O 3 thin film p-n homojunction was fabricated. The current-voltage ( I-V) characteristic of the homojunction device showed a good rectifying behavior. This result is suggested that the Zn doped β -Ga 2 O 3 nanowires showed p-type conductivity. [ABSTRACT FROM AUTHOR]

The corrosion resistance of a high Zn (11 wt%) aluminum alloy was found to be significantly improved by 45% when doped with Y (solid solution limit 1.4 wt %), while the hardness of the material is only reduced by 3.5%. Although corrosion is frequently observed in the grain boundaries of high Zn aluminum alloys, it is not observed in the grain boundary of the Y-included alloys under current approach, in spite of the increased volume of grain boundary phases. The content of Mg and Zn decreased in the grain boundary precipitates as the Y content increases, leading to an increase of the corrosion potential of these grain boundary phases. The calculated atomic binding energies, diffusion energies and surface energies suggested that Y substitution has improved the binding forces between alloy elements Mg, Cu, Zn and Al, but has a different effect on Cr. The precipitates in grain boundaries appear to have converted from the Al-based solid solution into a more stable intermetallic compound of MgZn 2 -type. • The corrosion resistance of the high Zn (11 wt%) aluminum alloy was found to be significantly improved by 45% with 1.4 wt% Y addition. • Corrosion is not observed in the grain boundary of the Y-doped alloys under current approach. • The content of Mg and Zn decreased in the grain boundary precipitates leading to an increase of the corrosion potential. • DFT-calculations suggested that Y substitution has improved the binding forces between alloy elements Mg, Cu, Zn and Al. [ABSTRACT FROM AUTHOR]