Search

Your search keyword '"Ko, Young Jin"' showing total 552 results
Start Over Author "Ko, Young Jin"
552 results on '"Ko, Young Jin"'

3. Development and Application of an Active Pharmacovigilance Framework Based on Electronic Healthcare Records from Multiple Centers in Korea

Author

Choe, Seon, Lee, Suhyun, Park, Chan Hee, Lee, Jeong Hoon, Kim, Hyo Jung, Byeon, Sun-ju, Choi, Jeong-Hee, Yang, Hyeon-Jong, Sim, Da Woon, Cho, Bum-Joo, Koo, Hoseok, Kang, Min-Gyu, Jeong, Ji Bong, Choi, In Young, Kim, Sae-Hoon, Kim, Woo Jin, Jung, Jae-Woo, Lhee, Sang-Hoon, Ko, Young-Jin, Park, Hye-Kyung, Kang, Dong Yoon, and Kim, Ju Han

Published
2023
Full Text
View/download PDF

25. Do employees and firms benefit from autonomous work practice? Curvilinear effects on collective turnover and productivity of firms.

Author

Sung, Sun Young, Choi, Jin Nam, and Ko, Young Jin

Subjects
EMPLOYEE benefits, PERSONNEL management, WORK design
Abstract

The present study focuses on the opportunity dimension of the ability–motivation–opportunity framework and explores the implications of autonomous work practice (AWP) for the collective turnover and productivity of firms. Given the trade-offs between the costs and benefits of AWP and its potential double-edged sword effects, we adopt the interdisciplinary perspective on job design (i.e. mechanistic and motivational models) as basis to theorize the curvilinear effects of AWP. We further hypothesize the interaction between AWP and work flexibility, consistent with the internal fit perspective of strategic human resource management. The current framework is validated by analyzing multisource, time-lagged data collected from 1,240 firms over a two-year period. The analysis confirms the hypothesized curvilinear effects of AWP, in which collective turnover is low only when the level of AWP is moderate. The detriment of a high level of AWP on increasing collective turnover is amplified for firms with low work flexibility. By contrast, firm productivity is high when the AWP level is either low or high, and the benefit of a high level of AWP on increasing productivity is pronounced for firms with high work flexibility. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

29. Non-modified Thermally-derived Onion-like Carbon As Electrocatalyst for [VO]2+/[VO2]+ Redox Flow Battery

Author

Ko, Young-Jin, Cho, Jung-Min, Jeong, Doo Seok, Kim, Inho, Choi, Heon-Jin, and Lee, Wook-Seong

Subjects
Condensed Matter - Materials Science
Abstract

We report the nanodiamond-derived onion-like carbon successfully applied as an electrocatalyst for [VO]2+/[VO2]+ redox flow battery, as drop-coated (in the as-synthesized state) on glassy carbon or carbon felt electrodes. We show that its reversibility and catalytic activity in its as-synthesized state was comparable to some of the best data in the literature which employed surface modifications. We clarified the origin of such excellent performances by physical/electrochemical analyses., Comment: 11 pages

Published
2016

36. Bioproduction of porphyrins, phycobilins, and their proteins using microbial cell factories: engineering, metabolic regulations, challenges, and perspectives.

Author

Ko, Young Jin, Lee, Myeong-Eun, Cho, Byeong-Hyeon, Kim, Minhye, Hyeon, Jeong Eun, Han, Joo Hee, and Han, Sung Ok

Subjects
*MICROBIAL cells, *METABOLIC regulation, *PORPHYRINS, *METALLOPORPHYRINS, *MICROBIAL biotechnology, *SPECIALTY chemicals
Abstract

Porphyrins, phycobilins, and their proteins have abundant π-electrons and strongly absorb visible light, some of which bind a metal ion in the center. Because of the structural and optical properties, they not only play critical roles as an essential component in natural systems but also have attracted much attention as a high value specialty chemical in various fields, including renewable energy, cosmetics, medicines, and foods. However, their commercial application seems to be still limited because the market price of porphyrins and phycobilins is generally expensive to apply them easily. Furthermore, their petroleum-based chemical synthesis is energy-intensive and emits a pollutant. Recently, to replace petroleum-based production, many studies on the bioproduction of metalloporphyrins, including Zn-porphyrin, Co-porphyrin, and heme, porphyrin derivatives including chlorophyll, biliverdin, and phycobilins, and their proteins including hemoproteins, phycobiliproteins, and phytochromes from renewable carbon sources using microbial cell factories have been reported. This review outlines recent advances in the bioproduction of porphyrins, phycobilins, and their proteins using microbial cell factories developed by various microbial biotechnology techniques, provides well-organized information on metabolic regulations of the porphyrin metabolism, and then critically discusses challenges and future perspectives. Through these, it is expected to be able to achieve possible solutions and insights and to develop an outstanding platform to be applied to the industry in future research. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

37. Extrinsic hydrophobicity-controlled silver nanoparticles as efficient and stable catalysts for CO2 electrolysis.

Author

Ko, Young-Jin, Lim, Chulwan, Jin, Junyoung, Kim, Min Gyu, Lee, Ji Yeong, Seong, Tae-Yeon, Lee, Kwan-Young, Min, Byoung Koun, Choi, Jae-Young, Noh, Taegeun, Hwang, Gyu Weon, Lee, Woong Hee, and Oh, Hyung-Suk

Subjects
SILVER nanoparticles, COMPUTED tomography, ELECTROLYTIC reduction, ELECTROCATALYSTS, HYDROGEN evolution reactions, ELECTROLYSIS, SILVER catalysts, MASS transfer, PHOTOCATHODES
Abstract

To realize economically feasible electrochemical CO2 conversion, achieving a high partial current density for value-added products is particularly vital. However, acceleration of the hydrogen evolution reaction due to cathode flooding in a high-current-density region makes this challenging. Herein, we find that partially ligand-derived Ag nanoparticles (Ag-NPs) could prevent electrolyte flooding while maintaining catalytic activity for CO2 electroreduction. This results in a high Faradaic efficiency for CO (>90%) and high partial current density (298.39 mA cm‒2), even under harsh stability test conditions (3.4 V). The suppressed splitting/detachment of Ag particles, due to the lipid ligand, enhance the uniform hydrophobicity retention of the Ag-NP electrode at high cathodic overpotentials and prevent flooding and current fluctuations. The mass transfer of gaseous CO2 is maintained in the catalytic region of several hundred nanometers, with the smooth formation of a triple phase boundary, which facilitate the occurrence of CO2RR instead of HER. We analyze catalyst degradation and cathode flooding during CO2 electrolysis through identical-location transmission electron microscopy and operando synchrotron-based X-ray computed tomography. This study develops an efficient strategy for designing active and durable electrocatalysts for CO2 electrolysis. A key factor for the electrochemical reduction of CO2 to CO is limiting the competing H2 evolution reaction. Here, authors use real-time synchrotron X-ray computed tomography to show that a silver nanoparticle-ligand catalyst structure improves water management, thereby maintaining CO production. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

42. Activity Restoration of Pt–Ni Octahedron via Phase Recovery for Anion Exchange Membrane‐Unitized Regenerative Fuel Cells.

Author

Oh, Cheoulwoo, Han, Man Ho, Ko, Young‐Jin, Cho, Jun Sik, Pin, Min Wook, Strasser, Peter, Choi, Jae‐Young, Kim, Hansung, Choi, Chang Hyuck, Lee, Woong Hee, and Oh, Hyung‐Suk

Subjects
FUEL cells, OXYGEN evolution reactions, OXYGEN reduction, OCTAHEDRA, ION-permeable membranes, WATER electrolysis, ENERGY function
Abstract

Unitized regenerative fuel cells (URFCs) offer a cost‐effective solution for energy conversion by functioning as both fuel cells and electrolyzers. Anion‐exchange membrane‐based URFCs (AEM‐URFCs) require bifunctional electrocatalysts, such as Pt–Ir alloys, for the oxygen evolution reaction (water electrolysis mode) and oxygen reduction reaction (fuel cell mode). However, the low stability of Pt in alkaline media and the high cost of Ir remain challenges for the widespread application of these URFCs. In this study, a Pt–Ni octahedral alloy is synthesized to replace Ir with Ni as the oxygen evolution reaction catalyst. The alloying effect of Pt–Ni inhibits the dissolution of Pt and transforms PtOx to metallic Pt via a recovery process, thereby providing a new operational strategy for improving the durability of AEM‐URFCs. Remarkably, the performance of the AEM‐URFC single cell is maintained over ten cycles after the recovery process, demonstrating the viability of this approach for long‐term operations. These findings pave the way for broader applications and advancements of AEM‐URFCs. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

44. Bioproduction of porphyrins, phycobilins, and their proteins using microbial cell factories: engineering, metabolic regulations, challenges, and perspectives

Author

Ko, Young Jin, Lee, Myeong-Eun, Cho, Byeong-Hyeon, Kim, Minhye, Hyeon, Jeong Eun, Han, Joo Hee, and Han, Sung Ok

Subjects
General Medicine, Applied Microbiology and Biotechnology, Biotechnology
Abstract

Porphyrins, phycobilins, and their proteins have abundant π-electrons and strongly absorb visible light, some of which bind a metal ion in the center. Because of the structural and optical properties, they not only play critical roles as an essential component in natural systems but also have attracted much attention as a high value specialty chemical in various fields, including renewable energy, cosmetics, medicines, and foods. However, their commercial application seems to be still limited because the market price of porphyrins and phycobilins is generally expensive to apply them easily. Furthermore, their petroleum-based chemical synthesis is energy-intensive and emits a pollutant. Recently, to replace petroleum-based production, many studies on the bioproduction of metalloporphyrins, including Zn-porphyrin, Co-porphyrin, and heme, porphyrin derivatives including chlorophyll, biliverdin, and phycobilins, and their proteins including hemoproteins, phycobiliproteins, and phytochromes from renewable carbon sources using microbial cell factories have been reported. This review outlines recent advances in the bioproduction of porphyrins, phycobilins, and their proteins using microbial cell factories developed by various microbial biotechnology techniques, provides well-organized information on metabolic regulations of the porphyrin metabolism, and then critically discusses challenges and future perspectives. Through these, it is expected to be able to achieve possible solutions and insights and to develop an outstanding platform to be applied to the industry in future research.

Published
2023

50. Electrochemically robust oxide-supported dendritic Pt and Ir nanoparticles for highly effective polymer electrolyte membrane-unitized regenerative fuel cells

Author

Ko, Young-Jin, primary, Kim, Hyunchul, additional, Lee, Woong Hee, additional, Han, Man Ho, additional, Oh, Cheoulwoo, additional, Choi, Chang Hyuck, additional, Kim, Woong, additional, Baik, Jeong Min, additional, Choi, Jae-Young, additional, Strasser, Peter, additional, and Oh, Hyung-Suk, additional

Published
2023
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results