Kinetics of charge transfer and oxygen evolution via surface functionalization at the transition metal based catalysts

Department of Materials Science and EngineeringIt has been attracting many attentions to develop a renewable, sustainable way to replace fossil-fuel based energy systems. Among the many candidates, hydrogen based energy systems have possibility of clean and secure future due to low-carbon society. Water splitting has huge potential for production of hydrogen in a clean way, for its source is water - renewable and nearly infinite source. However, it is only 4% portion in hydrogen production because of high cost and lack of industrial foundation. To deal with these problems, one of the solution is to develop the low-cost and highly efficient catalyst for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) to replace the noble metals (Pt) and precious metal oxides (RuO2 and IrO2), respectively. Especially, it is important to consider charge transfer kinetics for developing effective electrocatalyst. In this viewpoint, two main strategy were used in this study. One is the nitrogen (N) doped graphene quantum dots functionalization of perovskite oxide for better OER electrocatalyst, the other is adding conductive copper (Cu) ions to nickel phosphide (Ni-P) as an effective bifunctional electrocatalyst for overall water splitting. First N-doped graphene quantum dot functionalized LaxSr1-xCoO3 was synthesized as a highly active electrocatalyst for OER to deal with sluggish kinetics of OER, bottleneck for water splitting. Perovskite oxide ABO3 (A: alkaline or rare earth metal, B: transition metal) have been attracting many attentions due to flexible electronic structure, high activity descriptor, good stability, etc. Among them, LaxSr1-xCoO3 have received many attentions as a highly active catalyst. And applying N doped-graphene quantum dot is a promising way for engineering of perovskite oxide to build high-performance OER catalyst by controlling charge transfer in the catalyst. Second, Cu-doped Ni-P was synthesized by electrodeposition for effective electrocatalyst for overall water splitting. The incorporation of Cu into the Ni-P is expected to improve the electrocatalytic performances because of the reduction of charge transfer resistance and opposite sign of adsorption energy with hydrogen on Cu compared with that of Ni. It could be functioned as bifunctional electrocatalyst for overall water splitting. Finally, moisture formed on the surface was removed effectively by using water splitting reactions, which convert water into volatile hydrogen/oxygen gases. It was realized by 2-dimensional device with interdigitated pattern coated with highly active electrocatalyst NiCu-P for water splitting.clos

Anti-Inflammatory Effects of Bangpungtongsung-San, a Traditional Herbal Prescription

Bangpungtongsung-san (BPTS), a traditional oriental herbal prescription, is widely used for expelling wind, draining heat, and providing general improvement to the immune system. In this study, we investigated the effects of BPTS on induction of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), proinflammatory cytokines, nuclear factor-kappa B (NF-κB), and mitogen-activated protein kinases (MAPKs) in lipopolysaccharide- (LPS- ) stimulated Raw 264.7 cells, and on paw edema in rats. At concentrations of 0.5, 0.75, and 1 mg/mL, treatment with BPTS inhibited levels of expression of LPS-induced NF-κB and MAPKs (ERK, JNK, and p38) as well as production of proinflammatory mediators, such as nitric oxide (NO), prostaglandin E2 (PGE2), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) by LPS. These results suggest that BPTS may exert anti-inflammatory effects via reduction of proinflammatory mediators, including NO, PGE2, TNF-α, and IL-6 through suppression of the signaling pathways of NF-κB and MAPKs in LPS-induced macrophages. In addition, using the carrageenan-induced paw edema assay, an antiedema effect of BPTS was observed in rats. These findings may provide scientific evidence validating the use of BPTS in treatment of patients with heat syndrome in Korean oriental medicine

A TEXT MINING APPROACH TO THE ANALYSIS OF INFORMATION SECURITY AWARENESS: KOREA, UNITED STATES, AND CHINA

Recently in Korea, the importance of information security awareness has been receiving a growing attention. Attacks such as social engineering and ransomware are hard to prevent because it cannot be solved by information security technology. Also, the profitability of information security industry has been decreasing for years. Because of this, many companies try to find a new growth-engine and an entry to the foreign market. The main purpose of this paper is to draw out some information security issues that people of each country think and to analyze it. Finally, this study identifies issues and suggests how to improve the situation in Korea. For this, Topic Modeling analysis has been used to find information security issues of each country. Moreover, the score of sentiment analysis has been used to compare each country. The study contributes to the literature by exploring and explaining what critical issues are and how to improve the situation based on the identified issues of the Korean information security industry. Also, this study adds to the literature by demonstrating how text mining can be applied to the context of information security awareness. From a pragmatic perspective, the study has the implications for information security enterprises. This study is expected to provide a new and realistic method of analyzing domestic and foreign issues using the analyzing real data of the Twitter API