The effect of pH control on synthesis of Sr doped barium titanate nanopowder by oxalate precipitation method

Sr substituted BaTiO₃ (BST) nanopowders were prepared using oxalate co-precipitation methods. During synthesis, oxygen was applied to the oxalate solution in order to control the oxidation states of Ti. Control of pH in the solution results in different crystalline phases of the powders after calcination; pure perovskite BST was obtained in the powder prepared at pH 3 solution, while perovskite BaTiO₃ (BTO) and impurities were observed in powders prepared at pH 1 solution. Phase transformation from amorphous to crystalline BST during heat treatment was discussed by different analysis technique. Also, morphology and elemental distribution of the pure BST was investigated.     

Highly stable barium zirconate supported nickel oxide catalyst for dry reforming of methane: From powders toward shaped catalysts

We report the barium zirconate supported NiO_x catalysts (NiO_x/BZO) for dry reforming of methane and feasibility test for their industrial application by using temperature-regulated chemical vapor deposition together with extrusion. Nickel oxide nanoparticles are well deposited and dispersed on BZO powders as well as structures in a gear form, showing high catalytic activity and extraordinary stability even at relatively lower temperature and higher space velocity. The NiO_x/BZO catalyst are highly coke resistant for 50 h operation with almost negligible agglomeration of NiO_x nanoparticles. Judging from XPS and high ion conducting properties of BZO supports, the –OH or –O species are expected to play an important role in promoting the self-decoking of surface carbon species to form CO and CO_2.     

Microstructure and mechanical properties of friction stir welded and laser welded high entropy alloy CrMnFeCoNi

The high entropy alloy CrMnFeCoNi has been shown to have promising structural properties. For a new alloy to be used in a structural application it should be weldable. In the present study, friction stir welding (FSW) and laser welding (LW) techniques were used to butt weld thin plates of CrMnFeCoNi. The microstructure, chemical homogeneity and mechanical behavior of the welds were characterized and compared with the base metal. The tensile stress-strain behavior of the welded specimens were reasonable when compared with that of the base metal. FSW refined the grain size in the weld region by a factor of ～14 when compared with the base metal. High-angle annular dark field transmission electron microscopy in combination with energy dispersive X-ray spectroscopy showed chemical inhomogeneity between dendritic and interdendritic regions in the fusion zone of LW. Large fluctuations in composition (up to 15 at%) did not change the crystal structure in the fusion zone. Hardness measurements were carried out in the weld cross section and discussed in view of the grain size, low angle grain boundaries and twin boundaries in FSW specimens and the dendritic microstructure in LW specimens.     

Hepatoprotective effect of Handaeri-gomchi (Ligularia fischeri var. spiciformis Nakai) extract against chronic alcohol-induced liver damage in rats

Handaeri-gomchi (Ligularia fischeri var. spiciformis Nakai) (LF) is well known as a medicinal plant in Korea, especially to treat a variety of human disease including hepatic function failure. In this study, we examined the activity of LF extract against the liver injuries and oxidative stress by chronic alcohol in Spargue-Dawley rats. Severe liver damage caused by alcohol intake with increasing activity of hepatic markers was decreased in the group of rats fed LF extract. The results were confirmed through hematoxylin and eosin staining. Antioxidative capacity was decreased by alcohol but it was recovered by LF extract. Elevated indicators of oxidative stress by chronic alcohol were diminished in the group of LF extract. Furthermore, LF extracts increased antioxidative capacity and the activity of antioxidant enzymes. In conclusion, LF extract has a protective effect against chronic alcohol hepatotoxicity, suggesting it could be developed as a functional food or medicine for protection of liver disease.     

Plasma-polymerized n-hexane and its utilization as multilayer moisture-barrier film with aluminum oxide

Organic-inorganic multilayer structures were prepared for a moisture barrier. As the organic polymer and inorganic layers, plasma-polymerized n-hexane and aluminum-oxide layers were utilized, respectively. The plasma polymerization of n-hexane was confirmed by the appearance of carbon double bonds in the produced polymer layer. The organic and inorganic layers were prepared sequentially in vacuum, and the repeated growth sequence produced the multilayer structures. The organic-inorganic multilayer structures show about 35% better moisture-barrier property than those obtained from individual organic and inorganic layers.     

Microfluidic extraction using two phase laminar flow for chemical and biological applications

We review the state of the art in microfluidic separation technique based two-phase laminar flow with an application focus on chemical and biological sample. As we describe herein, two-phase laminar flow in the microfluidic extraction has several biological and engineering advantages over other methods including high reproducibility, biocompatibility, and selectivity. We review advances in applications of two-phase laminar flow and examine key parameters such as flow rate, phase composition, and surface charge property, how these can affect extract performance with the technology including microfluidic separation system. A special technology focus is given to emerging novel integrative microfluidic extraction, which aims to merge aqueous phase laminar flow and electric field technologies into simple packages. We conclude with a brief discussion of some of the emerging challenges in the field and some of the approaches that are likely to enhance their application.