DSpace Collection:http://hdl.handle.net/10203/6132024-03-29T09:03:52Z2024-03-29T09:03:52ZStrategic analysis on sizing of flooding valve for successful accident management of small modular reactorHyo Jun AnJae Hyung ParkChang Hyun SongLee, Jeong-IkYonghee KimSung Joong Kimhttp://hdl.handle.net/10203/3184762024-03-11T07:00:14Z2024-03-01T00:00:00ZTitle: Strategic analysis on sizing of flooding valve for successful accident management of small modular reactor
Authors: Hyo Jun An; Jae Hyung Park; Chang Hyun Song; Lee, Jeong-Ik; Yonghee Kim; Sung Joong Kim2024-03-01T00:00:00ZDetermination of the diffusion coefficient in electrodeposition reactions by electrochemical impedance spectroscopy: a case study of cobalt in molten LiCl-KCl saltYun, Jong-IlPark, Jun WooCha, Han Limhttp://hdl.handle.net/10203/3184682024-03-15T07:00:32Z2024-03-01T00:00:00ZTitle: Determination of the diffusion coefficient in electrodeposition reactions by electrochemical impedance spectroscopy: a case study of cobalt in molten LiCl-KCl salt
Authors: Yun, Jong-Il; Park, Jun Woo; Cha, Han Lim2024-03-01T00:00:00ZCompensating isotope effect on molecular emission of hydroxyl and imidogen isotopologues in laser-induced plasmaChoi, Sung-UkJo, YongheumYun, Jong-Ilhttp://hdl.handle.net/10203/3175712024-01-09T05:00:29Z2024-02-01T00:00:00ZTitle: Compensating isotope effect on molecular emission of hydroxyl and imidogen isotopologues in laser-induced plasma
Authors: Choi, Sung-Uk; Jo, Yongheum; Yun, Jong-Il
Abstract: Background
The molecular isotopologues in laser-induced plasma exhibit riddling emission behaviors in terms of wavelength, intensity, and temporal evolution of spectra due to the isotope effect. Although this phenomenon introduces uncertainty to isotope analyses based on molecular spectra, its underlying mechanism remains undisclosed.
Results
In this study, laser-induced breakdown spectroscopy (LIBS) is employed to identify the emission behavior of hydrogen, oxygen, and nitrogen isotopologues in a plasma plume. The goal is to discern the details of the isotope effect and mitigate resulting uncertainty. The molecular emissions of hydroxyl (OH) and imidogen (NH) were measured from plasma ablated on isotopically enriched water samples. Time-resolved detection clearly reveals distinct isotopic disparities in intensity variation and optimum gate delay, which were attributed to plasma thermo-hydrodynamics. Lighter isotopologues exhibit earlier and faster associations than their heavier counterparts due to their fast reaction rates and expansion velocities. The extent of the isotope effect hinged on plasma characteristics governed by measurement conditions. Consequently, comparing spectral intensity between molecular isotopologues cannot directly indicate the nominal isotope abundance of the sample. To address it, a compensation strategy has been devised, quantifying isotope effects through parameters like the slope and optimum delay of time-resolved detection. The approach successfully predicts nominal isotope abundance using compensated intensity ratios, with an absolute bias of less than 3 %.
Significance
This study not only offered fundamental insights into the isotope effect in laser-induced plasma but also proposed an alternative method for isotope quantification that circumvents complicated calibration processes.2024-02-01T00:00:00ZUniformly scalable and stackable porous transport layer manufactured by tape casting and calendering for efficient water electrolysisPark, Seong HyeonKoo, Jong UnPark, Young JuneJang, SeungsooLee, Kang TaekHan, Hyuk SuRyu, Ho Jinhttp://hdl.handle.net/10203/3180452024-02-14T03:00:25Z2024-02-01T00:00:00ZTitle: Uniformly scalable and stackable porous transport layer manufactured by tape casting and calendering for efficient water electrolysis
Authors: Park, Seong Hyeon; Koo, Jong Un; Park, Young June; Jang, Seungsoo; Lee, Kang Taek; Han, Hyuk Su; Ryu, Ho Jin
Abstract: Proton exchange membrane water electrolysis (PEMWE) stands out as the most promising and eco-friendly technology for directly converting renewable energy into hydrogen. A critical element within a PEMWE cell is the porous transport layer (PTL), typically constructed from Ti to withstand the rigorous conditions of water electrolysis. Herein, we present a cost-effective and viable fabrication process for Ti-PTLs, utilizing tape -casting method in combination with a lamination-roll calendering procedure, facilitating precise thickness control. By systematical fine-tuning the debinding conditions, we obtained a phase-pure Ti-PTL endowed with a highlyinterconnected pore structure. A comprehensive analysis of digitally twinned Ti-PTL, constructed through a state -of -the -art three-dimensional (3D) reconstruction process, reveals a remarkable uniformity in the open pore structures across Ti-PTLs of varying thicknesses, highlighting their considerable practical potential. Furthermore, the electrochemical performance of PEMWE cells using our Ti-PTLs surpassed that of the benchmark commercial Ti-PTL, demonstrating the significant promise of our tape -casting process followed by lamination-roll calendering procedure in practical Ti-PTL fabrication.2024-02-01T00:00:00Z