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In this study，nanocomposites of LaCePr-oxide (LCP) and Ni 0.8 Co 0.15 Al 0.05 LiO 2-δ (NCAL) with different contents of polyvinylidene fluoride (PVDF) were prepared and applied to solid oxide fuel cells. The composite materials were characterized by X-ray diffraction analysis (XRD), scanning electron microscope (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and electrochemical impedance spectrum (EIS). The effect of PVDF concentration on the conductivity and performance of the fuel cells was investigated. It was found that PVDF plays a template role of pore forming in the nanocomposites, and the changed microstructure by as-formed pores greatly influences the electrochemical property of the nanocomposites. The cell with 3 wt% PVDF heat-treated at 210 °C achieved the highest power density of 982 mW cm −2 at 520 °C, which enhanced performance by more than 57% than when no heat-treatment was implemented. It is 66% higher than the cell with no PVDF and no heat-treatment. Pores formed by PVDF after heat-treatment enlarged the triple phase boundary (TPB), which results in improved fuel cell performance. [ABSTRACT FROM AUTHOR]

Cubic garnet-type Al-contained Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 (Al-LLZTO) ceramics were prepared by conventional solid-state reaction using either Li 2 CO 3 or LiOH·H 2 O as Li source. The effects of Li source on the lithium ionic conductivity of Al-LLZTO ceramics were systematically investigated by comparing the synthesis processes and characteristics of the mother powders and the microstructures of the sintered pellets made with different Li sources. Different calcination processes of the raw materials mixtures with different Li sources are revealed by thermogravimetry-differential scanning calorimetry investigation. The mother powder derived from LiOH·H 2 O is of higher sintering activity than those made from Li 2 CO 3 at the same calcination temperature. For the LiOH·H 2 O-derived pellets, higher relative density and enhanced lithium-ion conductivity is achieved at a much lower sintering temperature of 1100 °C as compared with Li 2 CO 3 -derived pellets. The highest conductivity obtained at room temperature is 9.28 × 10 −4 S cm −1 , which is the highest value reported to date for the same Ta doping level. [ABSTRACT FROM AUTHOR]

The present work has been focused on the effects of surface-active element sulfur on welding properties during 10 kW high power laser welding of 304 stainless steel thick plate. Molten pool behavior, morphology feature of sulfide inclusions, metallographic structures, XRD patterns, microhardness, potentiodynamic polarization curves and pitted surface have been investigated and discussed. The results indicated that the added sulfur powder improved the weld depth by increasing molten metal fluidity, elongating molten pool and promoting heat transmission. The observed sulfide inclusions had small particle size of 0.65 μm in average and were distributed sparsely in weld joint. The WWS (weld joint with sulfur powder) had higher δ-ferrite content and finer grain size than the WWOS (weld joint without sulfur powder) and BM (base metal) due to the effects of sulfide inclusions on crystallizing process. The preferred orientations of γ-austenite along the (200) and (220) directions were promoted both in WWS and WWOS. Fine grain size and high δ-ferrite content led to high microhardness. The WWS had the highest microhardness among all the specimens. The WWOS and BM had a similar corrosion resistance. By comprehensive comparison, the WWS had a relative lower corrosion resistance than others, since sulfide inclusions in WWS not only had some benefits but also had some bad effects on corrosion property. [ABSTRACT FROM AUTHOR]

InAs infrared-sensitive solar cells are fabricated by using the films grown by the liquid phase epitaxy technique. The film microstructures are characterized by x-ray diffraction and scanning electronic microscopy. The current-voltage characteristics of the solar cells in the dark and under AM1.5 illumination at 300 K and 77 K are discussed. The conversion efficiency of p-InAs/n-sub InAs cells decreases when the thickness of the p-type film changes from 1.7 mm to 3.5 mm, which is caused by the reduced effective photons near p-n junction. The p-InAs/n-InAs/n-sub InAs solar cell with the conversion efficiency of 7.43% in 1-2.5 mm under AM1.5 at 77K is obtained. The short circuit current density increases dramatically with decreasing temperature due to the weakened effect of phonon scattering. [ABSTRACT FROM AUTHOR]

Highlights: [•] The low-temperature activity of Au–CeO2 catalyst in benzene oxidation depended mainly on the microstructure of CeO2. [•] The red-shift of F 2g band of CeO2 in Raman spectroscopy presented an obvious relevance with the low-temperature activity. [•] The red-shift of F 2g of Au–CeO2 catalyst prepared by Adsorbed-Layer Reactor Technique changed with the amount of NaOH pre-addition in preparation. [•] The doping of other metal ion could change F 2g and low-temperature activity. [Copyright &y& Elsevier]

It is difficult to investigate the formation process and occurrence states of water in multi-type reservoirs, due to the strong heterogeneity and complex microstructure of the fracture--cavity carbonate gas reservoirs. To date, there is no systematic study on the occurrence characteristics of multi-type formation water, especially through visual observation experiments. In this paper, a new creation method for visual micromodels based on CT scan images and microelectronic photolithography techniques was described. Subsequently, a gas--drive--water visual experiment was conducted to intuitively study the formation mechanism and the occurrence states of formation water. Then, the ImageJ gray analysis method was utilized to quantitatively investigate the gas-water saturation and the proportion of residual water film. Finally, the occurrence characteristics of formation water and its effects on gas seepage flow were comprehensively analyzed. Visual experimental results showed that: the migration processes of natural gas in different types of reservoirs are different; the water in multiple media consists of native movable water and residual water, and residual water is composed of secondary movable water and irreducible water; the residual water mainly occurs in different locations of different reservoirs with the forms of "water film", "water mass", "water column" and "water droplets"; the main influencing factors are capillary force, surface tension, displacement pressure and channel connectivity. Quantitative results reflect that the saturation of movable water and residual water are the parameters related directly to reservoir physical properties, pore structure and displacement pressure--the smaller the size of flow channel, the larger the space occupied by water film; the thickness proportion of water film is increasing exponentially with the channel size; the thickness proportion of water film decreases as the increase of displacement pressure; the thickness proportion of water film is essentially constant when the displacement pressure increases to a certain extent. The conducted visual investigation not only improves our intuitive understanding of the occurrence characteristics of formation water, but also provides a theoretical basis for the efficient development of fracture-cavity gas reservoirs. [ABSTRACT FROM AUTHOR]

Fe powder was coated with precipitate via a co-precipitation method using chlorate as the raw material. Then, the coated powder was heat treated under different conditions. The effects of the heat treatment atmosphere and temperature on the morphology, phase formation, crystallinity, grain size and lattice constant of the coated layer of powders were investigated using scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermogravimetric–differential scanning calorimetry (TG–DSC). The magnetic properties of the composite powder were determined using a Quantum Design vibrating sample magnetometer (QD-VSM). The results show that a fine, uniform coating layer of particles formed on the surface of the Fe powder after co-precipitation. Through heat treatment, the coating generated spinel Ni–Zn ferrite. The coated layer of argon-treated powders had a more uniform and regular morphology, purer phase and better crystallinity than air-treated powders. The saturation magnetisation first increased and subsequently decreased as the heating temperature increased. Similarly, the coercivity first decreased and subsequently increased. The sample annealed in air at 300 °C had the highest saturation magnetisation ( M s = 186.3 emu/g) and the lowest coercivity ( H c = 23.6 Oe), whereas the sample annealed in argon at 450 °C had the greatest saturation magnetisation ( M s = 196.4 emu/g) and relatively lower coercivity ( H c = 17.5 Oe). The powders annealed in argon atmosphere had better M s and lower H c than those annealed in air, mainly because coated powders heated in air produce a large amount of non-magnetic Fe 2 O 3 . [ABSTRACT FROM AUTHOR]

The mixture of ionic electrolyte Ce 0.8 Sm 0.05 Ca 0.15 O 2−δ (SCDC) and semiconductor Ni 0.8 Co 0.15 Al 0.05 LiO 2−δ (NCAL) layers was used for low temperature solid oxide fuel cell (LT-SOFC) applications. Using the as-prepared SCDC-NCAL semiconductor-ionic layer to replace the ionic SCDC electrolyte, following results have been obtained: the SCDC electrolyte fuel cell reached a lower voltage, 1.05 V, and lower power output, 415 mW cm −2 , compared to that using the semiconductor-ionic layer, 1.06 V and 617 mW cm −2 at 550 °C. The electrochemical impedance spectroscopy (EIS) was applied to investigate the electrochemical processes of the device; X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM) for the microstructure and morphology of the as-prepared materials. The results have illuminated that the introduction of semiconductor into ionic electrolyte could make extended triple phase boundary (TPB) area, which can provide more active sites to accelerate the fuel cell reactions and enhance the cell performance. Furthermore, we also discovered that the ionic SCDC and electronic NCAL should be in an appropriate composition to achieve a balanced ionic and electronic conductivity, which is the key issue for high performance semiconductor-ionic fuel cells. [ABSTRACT FROM AUTHOR]

Repetitious sizing treatment was used to modify the carbon fiber (CF) surface with carbon nanotubes (CNTs) for improving interfacial properties of CF/epoxy composites. Interlaminar shear and flexural results showed that mechanical properties of composites were significantly depended on the dispersion state and contents of CNTs in interfacial regions. Increases of 13.45% in interlaminar shear strength and 20.31% in flexural strength were achieved in quintuple sized-CF/epoxy composites, whereas excessive CNTs led to decrease of interfacial performance due to defects induced by agglomerated CNTs. Energy dispersive X-ray spectroscopy and force modulation atomic force microscope were used to detect the structure of interfacial phase and results indicated that gradient interfacial structure with various thicknesses was formed due to CNT incorporation. This means that such a simple and efficient method to improve interfacial performance of composites via regulating the fiber–matrix interphase structure was developed and showed great commercial application potential. [ABSTRACT FROM AUTHOR]

The effect of wheel speed as well as an additive Cr3C2 on the structure, crystalline texture, and magnetic properties of SmCo-based nanocrystalline magnets has been investigated. A low wheel speed of melt spinning of SmCo6.8(Cr3C2)0.2 promotes the formation of the Cr- and C-contained SmCo7 main phase with a \langle 0001\rangle out-of-plane texture, an average grain size of 38–60 nm, and a smooth {M} – {H} loop with sound rectangularity. On the other hand, for SmCo4.8(Cr3C2)0.2 alloys, H \mathrm{ci} significantly enhances from 28.1 to 36.6 kOe and {M} r increases from 23.2 to 28.0 emu/g with an increasing wheel speed from 30 to 50 m/s. A high wheel speed of 50 m/s in SmCo4.8(Cr3C2)0.2 contributes to the formation of dendrite SmCo5 grains with the short axis of about 20–50 nm and the long axis ranging from 100 nanometers to about 1 micrometer. An obviously preferential orientation along the $\langle 0001\rangle $ direction in SmCo5 grains is observed, which could be confirmed by the transmission electron microscope analysis and anisotropic magnetic behavior. The addition of Cr3C2 gives a hint toward the direction of texturing in SmCo-based magnets melt spun at high wheel speeds. [ABSTRACT FROM AUTHOR]