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Synthesis of nanoparticles using electrical explosion of Ni wire in Pt solution.
Joh, Dong-Woo,Jung, Taek-Kyun,Lee, Hyo-Soo,Kim, Do-Hyang American Scientific Publishers 2013 Journal of Nanoscience and Nanotechnology Vol.13 No.9
<P>The structure, size and morphology of nanoparticles produced by electrical explosion of Ni wire in Pt(NH3)2(NO2)2 solution were investigated. TEM results showed the formation of Ni and Pt nanoparticles as a result of the procedure. Ni nanoparticles were formed by the explosion of the Ni wire due to the passage of high current, evaporation, ionization, and cooling in the liquid medium. Ni nanoparticles were near spherical and showed particle sizes ranging from a few nanometers up to 50 nm. Pt nanoparticles were possible formed by the dissolution of OH- in Pt(NH3)2(NO2)2 solution during the electrical explosion of the Ni wire resulting in a plasma reaction. The formed Pt nanoparticles were ellipsoidal and showed particle sizes ranging to less than 5 nm. The lattice parameter of the Pt nanoparticles almost corresponded to the standard values reported. The obtained results indicate that Pt nanoparticles can be formed from a Pt solution without a reducing agent by electrical explosion of a metallic wire resulting in a plasma reaction.</P>
Joh, Dong Woo,Park, Jeong Hwa,Kim, Do Yeub,Yun, Byung-Hyun,Lee, Kang Taek Elsevier 2016 Journal of Power Sources Vol.320 No.-
<P><B>Abstract</B></P> <P>We develop a novel nanocomposite electrolyte, consisting of yttria-stabilized zirconia (YSZ) and erbia-stabilized bismuth oxide (ESB). The 20 mol% ESB-incorporated YSZ composite (20ESB-YSZ) achieves the high density (>97%) at the low sintering temperature of 800 °C. The microstructural analysis of 20ESB-YSZ reveals the characteristic nanocomposite structure of the highly percolated ESB phase at the YSZ grain boundaries (a few ∼ nm thick). The ionic conductivity of 20ESB-YSZ is increased by 5 times compared to that of the conventional YSZ due to the fast oxygen ion transport along the ESB phase. Moreover, this high conductivity is maintained up to 580 h, indicating high stability of the ESB-YSZ nanocomposite. In addition, the oxygen reduction reaction at the composite electrolyte/cathode interface is effectively enhanced (∼70%) at the temperature below 650 °C, mainly due to the fast dissociative oxygen adsorption on the ESB surface as well as the rapid oxygen ion incorporation into the ESB lattice. Thus, we believe this ESB-YSZ nanocomposite is a promising electrolyte for high performance solid oxide fuel cells at reduced temperatures.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A novel nanostructured ESB-YSZ composite electrolyte is developed. </LI> <LI> The nanocomposite electrolyte is sintered as low as 800 °C. </LI> <LI> ESB-YSZ exhibits 5 times higher ionic conductivity than that of YSZ. </LI> <LI> The high ionic conductivity is maintained for ∼600 h, demonstrating high stability. </LI> <LI> Oxygen reduction reaction with ESB-YSZ is effectively enhanced by ∼70% compared to YSZ. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Joh, Dong Woo,Park, Jeong Hwa,Kim, Doyeub,Wachsman, Eric D.,Lee, Kang Taek American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.10
<P>A functionally graded Bi1.6.Er0.4O3(ESB)/Y0.16Zr0.84O1.92(YSZ) bilayer electrolyte is successfully developed via a cost-effective screen printing process using nanoscale ESB powders on the tape-cast NiO-YSZ anode support. Because of the highly enhanced oxygen incorporation process at the cathode/electrolyte interface, a novel bilayer solid oxide fuel cell (SOFC) yields extremely high power density of similar to 2.1 W cm(-2) at 700 degrees C, which is a 2.4 times increase compared to that of the YSZ single electrolyte SOFC.</P>
Joh, Dong Woo,Shin, Hong Rim,Kim, Jongwoo,Lee, Kang Taek THE KOREAN SOCIETY OF INDUSTRIAL AND ENGINEERING 2019 JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY -S Vol.71 No.-
<P><B>Abstract</B></P> <P>In this work, for the first time, we systematically evaluated the temperature-dependent long-term stability of Na-doped SrSiO<SUB>3</SUB> super ionic conductors. The total conductivity of the Sr<SUB>0.6</SUB>Na<SUB>0.4</SUB>SiO<SUB>2.8</SUB> (40SNS) was monitored <I>in situ</I> by electrochemical impedance spectroscopy. The conductivity of the 40SNS at 700°C degraded within 1h due to the crystallization of Na<SUB>2</SUB>Si<SUB>2</SUB>O<SUB>5</SUB>. However, at 450°C, the initial conductivity of the 40SNS was firmly maintained for 260h without any observable phase transition. These results demonstrate the existence of a threshold temperature regime that suppresses the crystallization kinetics of the amorphous phase of Na-doped SrSiO<SUB>3</SUB> materials.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Woo-Sung Yun,Dong-Ik Kim,Ui-Jun Park,Kyung-Bok Lee,Young-Wook Kim,Kwang-Bo Park,Young-Soo Do,Jin-Hyun Joh 대한외과학회 2010 Annals of Surgical Treatment and Research(ASRT) Vol.78 No.4
Type Ⅲ endoleak is one of the causes of secondary intervention after endovascular aortic aneurysm repair (EVAR). We report two cases of a late type Ⅲ endoleak with a review of the literature. One case had a disconnected iliac limb and the other case was due to a defect of the main body fabric at the bifurcation level. Both cases were successfully treated by open conversion. Before open conversion, it should be determined how to get proximal aortic control (suprarenal vs. infrarenal and cross-clamping vs. balloon inflation). When the suprarenal aortic control is required, to reduce suprarenal clamping time, it is not necessary to remove the endograft completely. Partial endograft removal and a graft-to-graft anastomosis is an alternative, if it is well incorporated and not infected. Making a plan for delayed open conversion should be individualized according to the type and status of the endograft and the vascular anatomy.
( Dong Won Jang ),( Ina Jeong ),( Seon Jae Kim ),( Seok Won Kim ),( Soo Yeon Park ),( Yong Hwan Kwon ),( Yeon Oh Jeong ),( Ji Yeon Lee ),( Bo Sung Kim ),( Woo Shik Kim ),( Joon Sung Joh ) 대한결핵 및 호흡기학회 2014 Tuberculosis and Respiratory Diseases Vol.77 No.6
Recently, the incidence of pulmonary cryptococcosis is gradually increasing in rheumatoid arthritis (RA) patients. Pulmonary rheumatoid nodules (PRN) are rare manifestations of RA. Eighteen months ago, a 65-year old woman was admitted to hospital due to multiple nodules (2.5×2.1×2 cm) with cavitations in the right lower lobe. She was diagnosed with RA three year ago. She had been taking methotrexate, leflunomide, and triamcinolone. A video-assisted thoracoscopic surgery biopsy was performed and PRN was diagnosed. However, a newly growing huge opacity with cavitation was detected in the same site. Pulmonary cryptococcal infection was diagnosed through a transthoraciccomputed tomograpy guided needle biopsy. Cryptococcus antigen was detected in serum but not in cerebrospinal fluid. The patient was treated with oral fluconazole which resulted clinical improvement and regression of the nodule on a series of radiography. Herein, we report the case of pulmonary cryptococcosis occurring in the same location as that of the PRN.
Pulmonary Cryptococcosis That Mimicked Rheumatoid Nodule in Rheumatoid Arthritis Lesion
Jang, Dong Won,Jeong, Ina,Kim, Seon Jae,Kim, Seok Won,Park, Soo Yeon,Kwon, Yong Hwan,Jeong, Yeon Oh,Lee, Ji Yeon,Kim, Bo Sung,Kim, Woo-Shik,Joh, Joon-Sung The Korean Academy of Tuberculosis and Respiratory 2014 Tuberculosis and Respiratory Diseases Vol.77 No.6
Recently, the incidence of pulmonary cryptococcosis is gradually increasing in rheumatoid arthritis (RA) patients. Pulmonary rheumatoid nodules (PRN) are rare manifestations of RA. Eighteen months ago, a 65-year old woman was admitted to hospital due to multiple nodules ( $2.5{\times}2.1{\times}2cm$) with cavitations in the right lower lobe. She was diagnosed with RA three year ago. She had been taking methotrexate, leflunomide, and triamcinolone. A video-assisted thoracoscopic surgery biopsy was performed and PRN was diagnosed. However, a newly growing huge opacity with cavitation was detected in the same site. Pulmonary cryptococcal infection was diagnosed through a transthoracic computed tomograpy guided needle biopsy. Cryptococcus antigen was detected in serum but not in cerebrospinal fluid. The patient was treated with oral fluconazole which resulted clinical improvement and regression of the nodule on a series of radiography. Herein, we report the case of pulmonary cryptococcosis occurring in the same location as that of the PRN.