[en] In this study, we deposited low-resistivity molybdenum (Mo) thin films on soda-lime glass substrates with good adhesion. We adjusted various deposition parameters such as the sputtering power (52–102 W), working distance (5.5–9 cm) and annealing temperature (26–400 °C) to investigate their impact on the sheet resistance. By using a DC magnetron sputtering system, we obtained Mo thin films having the lowest sheet resistance of 0.190 Ω/□ with a sputtering power of 82 W, working distance of 6.5 cm, and annealing temperature of 400 °C; in addition, these films had good adhesivity. These Mo thin films were suitable for use as the Mo back contact in Cu(In,Ga)Se₂-based solar cells. - Highlights: ► Low-resistivity molybdenum (Mo) thin films with good adhesion were prepared. ► The working distance has a great influence on microstructure of Mo films. ► Decrease in working distance can apparently improve the resistivity of Mo films. ► The sheet resistance of 0.19 Ω/□ was obtained under 82 W, 6.5 cm, and 400 °C. ► These Mo films were suitable for use as back contact in Cu(In,Ga)Se₂‐solar cell.

[en] Highlights: • A simple solution method is used to make the particle-grown tube-like polyaniline. • Reaction time plays a great role on morphology and performance of polyaniline. • A C_F value of 437.8 F/g is got at 4 A/g for the tube-like polyaniline electrode. • Incorporating graphene oxide in polyaniline enhances electrochemical performance. • A C_F value of 475.0 F/g is obtained for the polyaniline/graphene oxide electrode. - Abstract: Polyaniline (PANI) is one of the most attractive materials for pseudocapacitors. To enhance the electrolyte diffusion and improve the electrochemical performance of the electrode, the well-designed morphology of PANI is required. Incorporating carbon materials is also benefic on enhancing the cycling stability as well as the mechanical and electrochemical properties of PANI. In this study, a simple solution method is applied to synthesize the particle-deposited tube-like PANI. Due to the well-defined structure, a specific capacitance (C_F) of 437.8 F/g is achieved at the current density of 4 A/g. Furthermore, the self-synthesized graphene oxide (GO) is simply mixed with the particle-deposited tube-like PANI to make a more efficient electrocapacitive material. An enhanced C_F value of 475.0 F/g is achieved for the optimized PANI/GO electrode, owing to the synergic effects of the pseudo-capacitance from PANI and the functional groups of GO, as well as the electrochemical double-layered capacitance from GO. After conducting 2000 cycles repeated charge/discharge process, the C_F retention of 90% and the average Coulombic efficiency of higher than 90% are also attained for the optimized PANI/GO electrode.

[en] Titanium dioxide (TiO₂) layers were prepared on a Ti substrate by using oxygen plasma immersion ion implantation (oxygen PIII). The surface chemical states, structure, and morphology of the layers were studied using X-ray photoelectron spectroscopy, X-ray diffraction, Raman microscopy, atomic force microscopy and scanning electron microscope. The mechanical properties, such as the Young's modulus and hardness, of the layers were investigated using nanoindentation testing. The Ti⁴⁺ chemical state was determined to be present on oxygen-PIII-treated surfaces, which consisted of nanocrystalline TiO₂ with a rutile structure. Compared with Ti substrates, the oxygen-PIII-treated surfaces exhibited decreased Young's moduli and hardness. Parameters indicating the blood compatibility of the oxygen-PIII-treated surfaces, including the clotting time and platelet adhesion and activation, were studied in vitro. Clotting time assays indicated that the clotting time of oxygen-PIII-treated surfaces was longer than that of the Ti substrate, which was associated with decreased fibrinogen adsorption. In conclusion, the surface characteristics and the blood compatibility of Ti implants can be modified and improved using oxygen PIII. - Highlights: • The Ti⁴⁺ chemical state was determined to be present on oxygen-PIII-treated surfaces. • The nanocrystalline TiO₂ with a rutile structure was formed on titanium surfaces. • A nanoporous TiO₂ layer in the rutile phase prepared using oxygen PIII treatment can be used to prolong blood clot formation.

[en] The microstructural variation and antibacterial properties of the AISI 304 stainless steel containing silver (Ag) element have been investigated by means of optical microscopy (OM), grazing incidence X-ray diffractometry (GIXRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectrometer (EDS). Furthermore, the antibacterial testing was performed according to JIS Z2801:2000 specification. As the alloy contained Ag elements, the microstructure of the alloys was a mixture of (α + γ + Ag-rich compound)-phases. The amounts of α phase and Ag-rich compound increased as Ag contents increased. The Ag-rich compound has FCC structure with the lattice parameter a = 0.251 nm. No precipitates were found within the matrix and grain boundaries in the present alloys after SHT. Moreover, when the alloy is added to Ag element, antibacterial property was seen obvious against E. coli. It has an AR nearly of 100%.

[en] The microstructure and mechanical behavior of the duplex Ti-4.8Al-2.5Mo-1.4V (Ti14) alloy were investigated by means of optical microscopy, electron microscopy, experimental model analysis, and hardness and tensile testing. During heat-treatment at between 600 and 1000 ^oC, the phase transformation sequence was found to be (α + β) → (α + β + α') → (α' + α'' + residual β). The (α' + α'' + residual β) structure exhibited the maximum yield strength (σ_y = 920 MPa), hardness (HR_C 36), and damping coefficient (188.3 x 10^-4). However, the (α + β) structure achieved the greatest elongation (∼15%). It is believed that the lath-like α' martensite not only increases the tensile strength, but also enhances the hardness of the Ti14 alloy. Moreover, it also plays a crucial role in increasing the damping capacity of the Ti14 alloy.

[en] Highlights: • The investigated Ti-25Ta alloy exhibited α′′ + β phases under the given solution heat treatment. • The heat-treated Ti-25Ta alloys possessed the surface hydrophilicity. • The Ti-25Ta alloy with (α′′ + β) phase exhibited well cell proliferation and adhesion behaviors. In this study, the microstructural, mechanical and biological characterizations of the Ti-25Ta (wt.%) alloy were investigated by means of optical microscope, X-ray diffraction, electron microscope, microhardness test, contact angle goniometer and in vitro cytotoxicity assay. As the alloy underwent heat-treatment at temperatures between 700 °C and 1000 °C for 30 min, its microstructure was a mixture of β phase and needle-like α′′ martensite phase. The analytical results indicated that the volume fraction of the needle-like α′′ martensite phase decreased with increasing heat-treatment temperature. The β transus temperature of the investigated Ti-25Ta alloy was below 700 °C. Moreover, the alloy heat-treated at 900 °C exhibited the maximum hardness Hv 743 ± 12.93. For wettability evaluation, all investigated samples possessed surface hydrophilicity. The cytotoxicity assay results also demonstrated that the heat-treated Ti-25Ta samples have well cell proliferation and adhesion behaviors. Therefore, these results and features could be used to further understand the relationship between the high temperature microstructure, mechanical behavior and in vivo biocompatibility of the Ti-25Ta alloy, and develop as a potential biomedical alloy.

[en] In this study, neodymium-doped yttrium orthovanadate (Nd:YVO_4) as a laser source with different scanning speeds was used on biomedical Ti surface. The microstructural and biological properties of laser-modified samples were investigated by means of optical microscope, electron microscope, X-ray diffraction, surface roughness instrument, contact angle and cell cytotoxicity assay. After laser modification, the rough volcano-like recast layer with micro-/nanoporous structure and wave-like recast layer with nanoporous structure were generated on the surfaces of laser-modified samples, respectively. It was also found out that, an α → (α + rutile-TiO_2) phase transition occurred on the recast layers of laser-modified samples. The Ti surface becomes hydrophilic at a high speed laser scanning. Moreover, the cell cytotoxicity assay demonstrated that laser-modified samples did not influence the cell adhesion and proliferation behaviors of osteoblast (MG-63) cell. The laser with 50 mm/s scanning speed induced formation of rough volcano-like recast layer accompanied with micro-/nanoporous structure, which can promote cell adhesion and proliferation of MG-63 cell on Ti surface. The results indicated that the laser treatment was a potential technology to enhance the biocompatibility for titanium. - Highlights: • Laser induced the formation of recast layer with micro-/nanoporous structure on Ti. • An α → (α + rutile-TiO_2) phase transition was observed within the recast layer. • The Ti surface becomes hydrophilic at a high speed laser scanning. • Laser-modified samples exhibit good biocompatibility to osteoblast (MG-63) cell