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607 results on '"Lee,Jong-Kwon"'

8. To realize a variety of structural color adjustments via lossy-dielectric-based Fabry–Perot cavity structure

Author

Rahman Md Abdur, Kim Dong Kyu, Lee Jong-Kwon, and Byun Ji Young

Subjects
fabry–perot cavity, lossy dielectric, reflection colors, strong light absorption, structural colors, Physics, QC1-999
Abstract

Structural colors with tunable properties have extensive applications in surface decoration, arts, absorbers, and optical filters. Planar structures have more advantages over other forms studied to date due to their easy manufacturability. Metal-insulator-metal-based structures are one of the known methods to fabricate structural colors where colors can be tuned mainly by the thickness of the intermediate lossless insulator layer. However, generating colors by MIM structure requires a thin metallic layer on top, and the top metals’ abrasiveness and/or oxidation may degrade the colors quickly. Thus, we propose a lossy dielectric layer to replace the top metallic layer as a solution to ensure the structure’s durability by preventing scratches and oxidation. Herein, CrON/Si3N4/Metal structures have been studied where theoretical investigations suggest that highly saturated colors can be generated in the lossy-lossless dielectric structures. Experimental data validated such simulations by revealing a range of vivid colors. Furthermore, these structures can easily achieve strong light absorption (SLA) even for a thick top layer of ∼100 nm. The colors realized by these structures are appeared due to a combination of the interference effect of the asymmetric Fabry–Perot cavity structure and the absorption rate in the CrOxN1−x layer.

Published
2022
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10. Trapped charge driven degradation of perovskite solar cells

Author

Ahn, Namyoung, Kwak, Kwisung, Jang, Min Seok, Yoon, Heetae, Lee, Byung Yang, Lee, Jong-Kwon, Pikhitsa, Peter V., Byun, Junseop, and Choi, Mansoo

Subjects
Condensed Matter - Materials Science
Abstract

Perovskite solar cells have shown fast deterioration during actual operation even with encapsulation, but its mechanism has been elusive. We found the fundamental mechanism for irreversible degradation of perovskite materials in which trapped charges regardless of the polarity play a decisive role. A novel experimental setup utilizing different polarity ions revealed that the moisture induced irreversible dissociation of perovskite materials is triggered by charges trapped along grain boundaries. Our finding clearly explained the intriguing observations why light soaking induces irreversible degradation while in the dark, moisture only causes reversible hydration, and why degradation begins from different side of interface for different charge extraction layers. The deprotonation of organic cations by trapped charge induced local electric field is attributed to the initiation of irreversible decomposition.

Published
2016
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15. Two tiered approaches combining alternative test methods and minimizing the use of reconstructed human cornea-like epithelium tests for the evaluation of eye irritation potency of test chemicals

Author

Ko, Kyung Yuk, Jeon, Hye Lyun, Kim, Joohwan, Kim, Tae Sung, Hong, Yoon-hee, Jeong, Mi Kyung, Park, Kyo-Hyun, Kim, Bae-Hwan, Park, Sera, Jang, Won-hee, Cho, Sun-A, An, Susun, Cho, Ah Rang, Yi, Jung-Sun, Kim, Ji-Young, Kim, Hak, Lee, Jong Kwon, and Park, Ki Sook

Published
2020
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29. International regulatory requirements for skin sensitization testing

Author

Daniel, Amber B., Strickland, Judy, Allen, David, Casati, Silvia, Zuang, Valérie, Barroso, João, Whelan, Maurice, Régimbald-Krnel, M.J., Kojima, Hajime, Nishikawa, Akiyoshi, Park, Hye-Kyung, Lee, Jong Kwon, Kim, Tae Sung, Delgado, Isabella, Rios, Ludmila, Yang, Ying, Wang, Gangli, and Kleinstreuer, Nicole

Published
2018
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40. Quarter-Annulus Si-Photodetector with Equal Inner and Outer Radii of Curvature for Reflective Photoplethysmography Sensors.

Author

Na, Yeeun, Kim, Chaehwan, Kim, Keunhoi, Kim, Tae Hyun, Kwon, Soo Hyun, Kang, Il-Suk, Jung, Young Woo, Kim, Tae Won, Cho, Deok-Ho, An, Jihwan, Lee, Jong-Kwon, and Park, Jongcheol

Subjects
PHOTOPLETHYSMOGRAPHY, QUANTUM efficiency, CURVATURE, BIOLOGICAL monitoring, HEART beat, PHOTODETECTORS
Abstract

Reflection-type photoplethysmography (PPG) pulse sensors used in wearable smart watches, true wireless stereo, etc., have been recently considered a key component for monitoring biological signals such as heart rate, SPO3, and blood pressure. Typically, the optical front end (OFE) of these PPG sensors is heterogeneously configured and packaged with light sources and receiver chips. In this paper, a novel quarter-annulus photodetector (NQAPD) with identical inner and outer radii of curvature has been developed using a plasma dicing process to realize a ring-type OFE receiver, which maximizes manufacturing efficiency and increases the detector collection area by 36.7% compared to the rectangular PD. The fabricated NQAPD exhibits a high quantum efficiency of over 90% in the wavelength of 500 nm to 740 nm and the highest quantum efficiency of 95% with a responsivity of 0.41 A/W at the wavelength of 530 nm. Also, the NQAPD is shown to increase the SNR of the PPG signal by 5 to 7.6 dB compared to the eight rectangular PDs. Thus, reflective PPG sensors constructed with NQAPD can be applied to various wearable devices requiring low power consumption, high performance, and cost-effectiveness. [ABSTRACT FROM AUTHOR]

Published
2024
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41. Characterization of novel HLA‐A*24:608N allele discovered in Koreans.

Author

Jeong, In Hwa, Lee, Jong Kwon, Kwon, Won Kyung, Song, Eun Young, Kim, Kyeong‐Hee, Lee, Jina, Jung, Sunmi, Jeong, Mijeong, Park, June‐Woo, and Kang, Eun Suk

Subjects
*ALLELES, *NUCLEOTIDE sequencing, *KOREANS, *BASE pairs, *FLOW cytometry
Abstract

A novel null HLA‐A*24 allele, HLA‐A*24:608N, was identified in five Korean subjects including three from a family and two separate individuals. This study was performed to discern its immunological function in transplantation settings. Because this null variant had deletions of approximately 12 k base pairs from intron 3 to 3′ end of the HLA‐A gene, low resolution HLA typing and amplicon‐based next generation sequencing (NGS) typing methods had failed to assign it. Hybrid capture‐based NGS method confirmed that this novel variant had a large deletion. T‐lymphocyte crossmatching by complement‐dependent lymphocytotoxicity and flow cytometry with a serum consisting anti‐HLA‐A24 antibody revealed negative results, implying that an individual with this allele would not carry a functioning A24 antigen. These findings highlight the importance of identifying a null HLA allele by employing appropriate molecular method and providing expected crossmatching outcomes in a real‐world transplantation setting. [ABSTRACT FROM AUTHOR]

Published
2024
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43. Reducing Microbial Contamination in Hematopoietic Stem Cell Products and Quality Improvement Strategy: Retrospective Analysis of 1996-2021 Data

Author

Ko, You Keun, primary, Lee, Jong Kwon, additional, Park, Hye Kyung, additional, Han, Ae Kyung, additional, Mun, Sun Kyoung, additional, Park, Hye Jeong, additional, Choung, Hae Kyoung, additional, Kim, Se Mi, additional, Choi, Kwang Mo, additional, Lee, Nam Yong, additional, Cho, Duck, additional, Kim, Dae Won, additional, and Kang, Eun-Suk, additional

Published
2023
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