查看更多>>摘要：? 2022 Elsevier B.V.In addition to the thermal and electrical characteristics of the thermoelectric material, the energy conversion efficiency of TE devices is influenced by other factors including the interface resistance, which in turn is affected by chemical changes or mechanical failure. We have investigated the use of FeTe as an electrode for iodine-doped PbTe. The telluride of iron has CTE and work function values that match well with those of PbTe. The FeTe/PbTe contact was determined as ohmic in nature with low resistance. Contact resistance and shear strength values were determined over aging times of up to 400 h at 573 K and were found to be nearly unchanged. In contrast, samples in which Fe was used as electrode showed significant decrease in shear strength and a significant increase in joint resistivity over the same aging conditions. From the electrical and thermal characterization, the conversion efficiency of the FeTe/Pb1.0004Te0.997I0.003/FeTe single leg was determined as 4.678% for Th = 673 K and Tc = 300 K.
查看更多>>摘要：? 2022 Elsevier B.V.In the present study, the sputtering process deposited tantalum oxide thin film onto AZ31B alloy, and the biocompatibility and degradation resistance were evaluated. The phase analysis by X-ray diffraction (XRD) and transmission electron microscopy (TEM) was carried out to understand the Ta-based thin films’ crystalline and amorphous nature thin film. The thin film surface chemical composition was investigated by X-ray Photoelectron Spectroscopy (XPS) which showed the elemental signals of O, Ta without any other impurities. Contact angle measurements verified the hydrophobic nature of the coated specimens. The corrosion studies revealed that corrosion resistance was significantly enhanced for the Ta-based thin-film coated Mg alloys than the uncoated bare counterpart by reducing corrosion current density from 2.886 × 10?4 to 1.20 × 10?5 A/cm2. Bioactivity of the coated specimens in SBF immersion showed apatite formation in 5 days. The hemocompatibility studies of the coatings showed the echinocytes morphology of the RBCs. In vitro, MTT assay exhibited more significant cell proliferation and cell viability of 100% at 7 days of incubation. The cell morphology studies showed improved cell attachment and cell growth by controlling magnesium ions' release into the cell culture media.
查看更多>>摘要：? 2022 Elsevier B.V.Electrowetting on dielectric (EWOD) has been developed dynamic blood glucose detection in many special areas of life. However, there are still disadvantages such as slow responsiveness, low sensitivity and poor reproducibility, even no bactericidal function. Herein, the superhydrophobic Ag-ZnO@STA/Zn composite device has been prepared by simple sol-gel and spin-coating techniques, in which Ag@STA nanoparticles are embedded into the interspaces of flower-like ZnO@STA nanosheets and formed the micro-nano hierarchical structure with large surface roughness. The EWOD performance of Ag-ZnO@STA/Zn device is optimized to achieve large contact angle (CA) modulation of 100° and superlow threshold voltage less than 1 V, which completely ensure the success application for the diabetes detection. The CA under voltage is used as a strategy for sensor response, the simulated physiological fluids are used as test liquid in EWOD, the prepared Ag-ZnO@STA/Zn device is endowed with high sensitivity detection ability to glucose with low concentration. More importantly, as the diabetes sensor, the Ag-ZnO@STA/Zn device has excellent anti-corrosion and bactericidal functions.
查看更多>>摘要：? 2022 Elsevier B.V.Doping engineering is an effective strategy to improve the hydrogen storage capacity of magnesium-based materials. Here, we report a magnesium composite containing trace amounts of nickel catalyst (Ni-Mg), in which Ni and Mg layers form a new structural phase. The test shows that Ni-Mg composite has a hydrogen storage capacity of 7.5 wt%, with rapid absorption/desorption kinetics and stable reversible absorption/desorption performance on cycling. Ni-Mg exhibits a superior hydrogen storage performance as compared to the MgNi alloys and Mg-based materials previously reported in the literature. We conclude that a new MgNi phase and MgNi2 intermetallic compound are formed during the H2 adsorption process. Based on the theoretical calculations, we show that Ni facilitates hydrogenation by accelerating the dissociation of H2 molecules into the H atoms, while the MgNi phase formed during the hydrogenation is conducive to the subsequent dehydrogenation, promoting H atoms diffusion between the subsurface and the surface. This work provides a guidance for the development of the efficient hydrogen storage materials.
查看更多>>摘要：? 2022 Elsevier B.V.Magnetoceramics composed of pure α-Fe crystals grown in an amorphous silicon carbonitride matrix were prepared using phenyl-silsesquiazane (PSSQZ) and iron oxide (Fe3O4) as precursors. Magnetoceramics with commercial polysilazane were also synthesized for comparison. The PSSQZ induced growth of only α-Fe crystals in the magnetoceramics because of the high C content of the phenyl group of PSSQZ and the ability of the precursor to control the Si content; moreover, Fe silicide was not formed. In addition, the effect of the chemical composition of the precursor on the crystal phase growth was confirmed via ab initio thermodynamic calculations. The growth of pure α-Fe crystals resulted in improvements in magnetic saturation from 10.62 to 27.82 emu/g. This study showed that the microstructure of the magnetoceramics could be controlled according to precursor composition, resulting in an improved magnetic property.
查看更多>>摘要：? 2022 Elsevier B.V.Mesoporous TiO2 (m-TiO2) have been often employed to improve the photovoltaic conversion efficiencies (PCEs) of the dye-sensitized solar cells (DSSCs). While when incorporated with a long-persistence-phosphor (LPP) layer, only a limited PCE enhancement was obtained for the resultant DSSCs. This is mainly due to that little incident sunlight can transport through the solid m-TiO2 photoanode films and then enter and excite the LPP layer. Here in this work, tunable amount of macropores were introduced into hierarchically porous TiO2 (h-TiO2) using polyvinylpyrrolidone (PVP) as pore-forming agent. As a result, the optimized DSSCs with h-TiO2/LPP photoanodes show the highest PCE of 8.05%, which is improved by 29.00% and 14.51%, compared to those with m-TiO2 and m-TiO2/LPP ones, respectively. Series of analysis indicates that the macropores benefit the transmission of incident sunlight through the h-TiO2 layer and reduce the light reflection at the interface of h-TiO2/LPP. Furthermore, the carbon-doping in TiO2 caused by PVP shifts up the Fermi level of TiO2 and the interface of h-TiO2/LPP enhances the separation of photo-generated carriers, both of which increase the open circuit voltage of the DSSCs. In addition, the DSSCs with h-TiO2-8/LPP photoanodes can well work in dark with a real PCE of 57.37%.
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