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1,088 results on '"Choi, Woo-Young"'

116. Long-term postoperative satisfaction and complications in nasal bone fracture patients according to fracture type, site, and severity

Author

Choi, Min Hyub, Cheon, Ji Seon, Son, Kyung Min, and Choi, Woo Young

Subjects
medicine.medical_specialty, Bone fractures, Esthetics, medicine.medical_treatment, Nasal bone, Fracture site, Postoperative complications, 03 medical and health sciences, 0302 clinical medicine, Patient satisfaction, medicine, 030223 otorhinolaryngology, Reduction (orthopedic surgery), Fracture type, Nasal bone fracture, business.industry, Incidence (epidemiology), 030206 dentistry, Surgery, Closed Fracture Reduction, Otorhinolaryngology, Original Article, Closed fracture reduction, business
Abstract

Background It is difficult to completely fix nasal bone fractures with closed reduction, as it is often accompanied by septal cartilage damage, and this often results in postoperative secondary deformities. Thus, patients are often reluctant to undergo closed reduction surgery. The present study aimed to evaluate aesthetic and functional satisfaction, as well as satisfaction with and complications of closed reduction, according to nasal bone fracture type. Methods The subjects were patients who underwent closed reduction under general anesthesia from January 2017 to December 2018. Based on the modified Murray classification, patients were classified into five groups according to the fracture site, septal fracture, and deviation. A total of 211 patients were sent a web-based survey on postoperative satisfaction and complications, as well as intention for revision and cosmetic surgery. Sixty-one patients (28.9%) responded. Results There were no significant differences in aesthetic and functional satisfaction or satisfaction with closed reduction according to the fracture type, site, or severity. Postoperative functional complications developed in 14 of 61 patients (22.95%). With 10 out of 24 (41.67%) patients (p = 0.044), the bilateral fracture with septal fracture or prominent septal deviation type had a higher incidence of complications than the other types. Conclusion The incidence of complications is higher for bilateral fracture with septal fracture or prominent septal deviation compared to the other nasal bone fracture types. Therefore, long-term follow-up after closed reduction surgery for this fracture type can aid in establishing additional postoperative treatment plans and improving patient satisfaction.

Published
2020

131. Machine Learning Based Optimization Technique for High-Capacity V-NAND Flash Memory

Author

Kim, Jisuk, additional, Kim, Earl, additional, Lee, Daehyeon, additional, Lee, Taeheon, additional, Ham, Daesik, additional, Yang, Miju, additional, Hwang, Wanha, additional, Kim, Jaeyoung, additional, Yoon, Sangyong, additional, Jeong, Youngwook, additional, Kim, Eunkyoung, additional, Song, Ki-Whan, additional, Song, Jai Hyuk, additional, Kim, Myungsuk, additional, and Choi, Woo Young, additional

Published
2021
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142. Oseltamivir-resistant pandemic (H1N1) 2009 virus, South Korea

Author

Yi, Hwajung, Lee, Joo-Yeon, Hong, Eun-Hye, Kim, Mi-Seon, Kwon, Donghyok, Choi, Jang-Hoon, Choi, Woo-Young, Kim, Ki-Soon, Lee, Jong-Koo, Oh, Hee-Bok, and Kang, Chun

Subjects
Epidemics -- South Korea -- Health aspects, Antiviral agents -- Health aspects, Drug resistance -- Health aspects, Influenza -- Health aspects, Disease susceptibility -- Health aspects, Health
Abstract

Since April 2009, pandemic (H1N1) 2009 has spread worldwide and caused the first influenza pandemic of the 21st century. Pandemic (H1N1) 2009 virus initially showed resistance to amantadine but susceptibility [...]

Published
2010
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143. Enhancement of Thermal Characteristics and On-Current in GAA MOSFET by Utilizing Al2O3-Based Dual-κ Spacer Structure

Author

Song, Young Suh, Kim, Sangwan, Kim, Jang Hyun, Kim, Garam, Lee, Jong-Ho, and Choi, Woo Young

Abstract

By utilizing the dual- $\kappa $ spacer (DS) technique, a novel structure has been proposed to improve the thermal characteristics and ON-current ( ${I}_{ \mathrm{\scriptscriptstyle ON}}{)}$ in gate-all-around (GAA) MOSFETs. The proposed GAA MOSFET structure utilizes DS, which contains aluminum oxide (Al2O3) as an inner spacer so that the self-heating effect (SHE) could be improved from the high thermal conductivity of Al2O3. To verify the proposed device structure, 3-D technology computer-aided design (TCAD) simulation has been performed through Synopsys Sentaurus tool. As a result, when the DS structure and Al2O3 are utilized in GAA MOSFET, the maximum lattice temperature ( ${T}_{\text {max}}{)}$ is improved from 628 to 509 K, and the thermal resistance ( ${R}_{\text {th}}{)}$ is improved by 49%. According to this thermal improvement, ${I}_{ \mathrm{\scriptscriptstyle ON}}$ and OFF-current ( ${I}_{ \mathrm{\scriptscriptstyle OFF}}{)}$ are also simultaneously improved in the proposed GAA MOSFET. Furthermore, since Al2O3 has lower permittivity than HfO2, the gate capacitance ( ${C}_{\text {gate}}{)}$ could also be improved in the proposed GAA MOSFET. In essence, the proposed GAA MOSFET structure utilizes high thermal conductivity and low permittivity of Al2O3 with DS structure.

Published
2023
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145. Single-switch quasi-resonant converter

Author

Kwon, Jung-Min, Choi, Woo-Young, and Kwon, Bong-Hwan

Subjects
Electric current converters -- Analysis, Resonators -- Analysis, Electric current converter, Business, Computers, Electronics, Electronics and electrical industries
Abstract

A single-switch quasi-resonant converter is proposed to obtain high efficiency. Using a variable switching frequency control, this converter is continuously operated at the critical conduction mode for soft switching of the power semiconductor switch. By the resonance, the proposed converter reduces the turn-on loss of the switch without additional active switches and alleviates the reverse-recovery losses of the rectifying diodes. Furthermore, the voltage stress of the rectifying diodes due to the output series resonant circuit is clamped to the output voltage. Experimental results for the 48-V/160-W converter at the variable switching frequency are obtained to show the performance of the proposed converter. Index Terms--Quasi-resonant converter, soft switching.

Published
2009

146. Single-stage soft-switching converter with boost type of active clamp for wide input voltage ranges

Author

Choi, Woo-Young, Kwon, Jung-Min, Lee, Jong-Jae, Jang, Hyeon-Yong, and Kwon, Bong-Hwan

Subjects
Electric current converters -- Design and construction, Clamping circuits -- Design and construction, Electric current rectifiers -- Design and construction, Rectifier instruments -- Design and construction, Voltage -- Control, Voltage -- Measurement, Electric current converter, Business, Electronics, Electronics and electrical industries
Abstract

A single-stage soft-switching converter is proposed for universal fine voltage applications. A boost type of active-clamp circuit is used to achieve zero-voltage switching operation of the power switches. A simple dc-link voltage feedback scheme is applied to the proposed converter. A resonant voltage-doubler rectifier helps the output diodes to achieve zero-current switching operation. The reverse-recovery losses of the output diodes can be eliminated without any additional components. The dc-link capacitor voltage can be reduced, providing reduced voltage stresses of switching devices. Furthermore, power conversion efficiency can be improved by the soft-switching operation of switching devices. The performance of the proposed converter is evaluated on a 160-W (50 V/3.2 A) experimental prototype. The proposed converter complies with International Electrotechnical Commission (IEC) 1000-3-2 Class-D requirements for the light-emitting diode power supply of large-sized liquid crystal displays, maintaining the dc-link capacitor voltage within 400 V under the universal line voltage (90-265 [V.sub.rms]). Index Terms--Active clamp, single stage, voltage-doubler rectifier, zero-current switching (ZCS), zero-voltage switching (ZVS).

Published
2009

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