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[en] Highlights: • Synthesis of Zn-ferrite nanoparticles by hydrothermal process and coated via PEG. • Effects of PEG coating on magnetic, physical, thermal, and bio-compatibility features. • Coated NPs show saturation magnetization and SLP, almost the same as uncoated ones. • Coated Nanoparticles were proven to be non-toxic.
[en] Highlights: • ScVO4:Ln3+ (Ln = Eu, Dy, Eu/Dy) powders were successfully prepared by a one-step green hydrothermal method. • The as-synthesized samples showed high crystallinity and a rich variety of morphologies. • Formation mechanism of multiform morphologies ScVO4 was proposed. • Muticolor light including white light can be obtained.
[en] Pb(Zr0.52Ti0.48)O3 nanocrystals were synthesized by a hydrothermal method. The poly(vinyl pyrrolidone) (PVP) was used as the surfactant to control growth of the Pb(Zr0.52Ti0.48)O3 nanocrystals. The effect of PVP concentration, reaction temperature and time on morphologies and crystallinity of Pb(Zr0.52Ti0.48)O3 nanocrystals were investigated. The tetragonal PbZr0.52Ti0.48O3 grains were obtained, as they were prepared at 200 °C for 4 h with PVP concentration from 0.1 to 10.0 g/L. With increasing the PVP concentration from 0.1 to 10.0 g/L, the size of PbZr0.52Ti0.48O3 grains decreased. When the PbZr0.52Ti0.48O3 grains were prepared at 200 °C for 12 h with PVP concentration of 6.0 g/L, the PbZr0.52Ti0.48O3 nanocrystals with average diameter of 30 nm were formed.
[en] To obtain outstanding electromagnetic microwave absorption (EMWA) properties, the rambutan-like dielectric–magnetic C@NiCo2O4 material was successfully prepared by a simple hydrothermal method, followed by a carbonization process. Benefiting from the unique rambutan-like structure, the dielectric–magnetic C@NiCo2O4 composites showed excellent microwave attenuation ability: minimum reflection loss (RLmin) value of − 39.0 dB at 17.4 GHz and wide effective absorption bandwidth (EAB, reflection loss exceeding − 10 dB) of 4.16 GHz (> 13.84 GHz) with a matching thickness of only 1.5 mm, which were much better than those of pure C and NiCo2O4. The superior properties might be due to multiple synergistic effects: magnetic loss (NiCo2O4), dielectric loss (C, NiCo2O4), the multi-reflections, scattering and interface relaxation resulting from mesoporous rambutan-like structures, and the dipole polarization to get good electromagnetic matching and high attenuation efficiency.
[en] Owing to the simultaneous occurrence of nucleation and nuclei aggregation in nanoprecipitation approach, the preparation of monodisperse nanospheres from polysaccharide remains a great challenge. Herein a two-step approach is presented for size controlled preparation of monodisperse polysaccharide-based nanospheres with PDI of 0.05 from starch acetate (SA). First, the starch acetate nanospheres (SANs) with average size in the range from 100 to 160 nm were produced by a moderate and constant hydrophobic interaction (MCHI) process. Second, based on principle of Ostwald ripening, a facile hydrothermal method was employed to modulate the size of the SANs obtained from the first step, yielding monodisperse nanospheres ranging from 200 to 1400 nm. This two-step method was also successfully applied to the preparation of ethyl cellulose nanospheres, which provided a facile strategy to prepare nanospheres from polysaccharides. Finally, SANs (744 nm) and ECNs (802 nm) were used to fabricate 2D photonic crystals by self-assembly, further verifying high monodispersity of obtained polysaccharide-based nanospheres. (paper)
[en] In spite of demonstrated application of nano barium titanate (BaTiO3) in biomedical applications, its antibacterial/fungal activity and biocompatibility studies are hitherto unexplored. Present work reports synthesis, characterization and assessment of antimicrobial and hemolytic activity of nano BaTiO3, owing to their potential futuristic biomedical applications. Nano BaTiO3 is prepared by surfactant (Hexadecyltrimethylammonium bromide, CTAB) assisted hydrothermal synthesis and is characterized by various analytical and spectroscopic techniques. Morphology of the as synthesized nano BaTiO3 is cubic in nature. Based on the characterization techniques, nano BaTiO3 synthesised using 15 mM CTAB (15-CBT) were considered for antimicrobial activity against various multidrug-resistant pathogens. Good inhibition activity was observed against C. albicans with MIC value of 0.37 mg ml−1 and MFC of 0.75 mg ml−1. C. albicans treated with 10 mg of 15-CBT showed only 30% cell viability. The anticandidal mechanism of nano BaTiO3 against C. albicans was attributed to decrease in ergosterol biosynthesis leading to cell death. Further, only 3% hemolytic activity on human blood RBCs was observed at 0.2 mg ml−1 of 15-CBT. The anticandidal activity and hemolytic activity of the synthesised nano BaTiO3 is systematically investigated and reported. (paper)
[en] Microporous zeolite adsorbent materials are widely used as a medium for separating gases. Adsorbent gas separation systems can run at ambient temperature and require minimal pressure to flow the input gas stream across the adsorbent bed. This allows for low energy consumption relative to other types of separation systems. Specific zeolites also have a high capacity and selectivity for the gases of interest, leading to compact and efficient separation systems. These characteristics are particularly advantageous for the application of signatures detection for non-proliferation, which often requires portable systems with low power draw. Savannah River National Laboratory currently is the leader in using zeolites for noble gas sampling for non-proliferation detection platforms. However, there is a constant customer need for improved sampling capabilities. Development of improved zeolite materials will lead to improved sampling technology. Microwave-assisted and conventional hydrothermal synthesis have been used to make a variety of zeolites tailored for noble gas separation. Materials characterization data collected in this project has been used to help guide the synthesis of improved zeolite materials. Candidate materials have been down-selected based on highest available surface area, maximum overall capacity for gas adsorption and highest selectivity. The creation of improved adsorbent materials initiated in this project will lead to development of more compact, efficient and effective noble gas collectors and concentrators. The work performed in this project will be used as a foundation for funding proposals for further material development as well as possible industrial applications.
[en] To our best knowledge, it is the first time to synthesize the single-phase BaFe12O19 hexaferrite by the single hydrothermal method at 220 °C. Meanwhile, effects of Fe/Ba ratio and KOH amount were also investigated. It was found that the proper Fe/Ba ratio could suppress the intermediate phase, such as α-Fe2O3 and BaFe2O4. One thing to be mentioned is that high alkaline system may be a key factor to prepare BaFe12O19 hexaferrite with even disk-like shape and narrow size distribution. The optimum Fe/Ba mole ratio is identified as 8:1, and the optimum dosage of KOH was 4.0 g for the preparation of single-phase BaFe12O19. Furthermore, the formation mechanism of disk-like BaFe12O19 hexaferrite was also discussed. - Highlights: ► Single-phase BaFe12O19 hexaferrite was synthesized by the single hydrothermal method. ► The only Fe/Ba mole ratio is identified as 8:1. ► The optimum amount of KOH was 4.0 g. ► Formation mechanism of disk-like shape for BaFe12O19 hexaferrite was discussed
[en] Highlights: • Hybrid organic-inorganic materials based on apatites. • Structural effect of glutamic acid on synthetic apatites. • Solid state circular dichroïsm of glutamic acid on apatites.
[en] Highlights: • ZnO nanorods (ZnO-NR) were prepared by hydrothermal processing. • Hydrothermal treatment using DAP provided nanoscale roughness onto the ZnO-NR. • Its hydrophobicity was the combination of Wenzel's mode with Cassie's mode. • The Leidenfrost point depended on the solid–liquid contact area ratio. • Providing nanoscale roughness decreased the Leidenfrost point.