Ion bean irradiation induced phase transformation study of LaAlO₃ by In-situ RHEED observation

Jonghan Won,James A. Valdez,Igor O. Usov 한국표면공학회 2023 한국표면공학회 학술발표회 초록집 Vol.2023 No.5

Autoignition and combustion behavior of emulsion droplet under elevated temperature and pressure conditions

Won, Jonghan,Baek, Seung Wook,Kim, Hyemin Elsevier 2018 ENERGY Vol.163 No.-

<P><B>Abstract</B></P> <P>In this study, experiments were conducted to investigate the combustion characteristics of an water-in-oil W/O emulsion droplet under elevated temperature and pressure conditions. The base fuel used was n-decane, and total volume ratios of 10, 20, and 30% of distilled water were mixed for producing the emulsion fuel. Span 80 with a volume ratio of 2% was added as a surfactant, and the emulsion fuel was homogeneously mixed via ultrasonication. The combustion process of an emulsion droplet was divided into five stages: droplet heating, classical combustion, puffing, secondary classical combustion, and surfactant combustion. The ignition delay decreased with elevated ambient temperatures, whereas an increase in the ambient pressure and water volume ratio resulted in longer ignition delays. The droplets did not ignite in 500 °C or 600 °C conditions at 1 bar because of the significant Stefan flow of fuel vapor. After droplet ignition, the droplet combustion process, including classical combustion, puffing, and surfactant combustion, followed. The average burning rate increased with ambient pressure, but it was insensitive to ambient temperatures and water volume ratios. After flame extinction, a secondary flame reappeared because of the combustion of surfactant and residues.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Combustion of a water/n-decane fuel emulsion droplet at high pressure and temperature condition was studied. </LI> <LI> Changes of ignition delay and combustion stage of emulsion fuel droplet were observed. </LI> <LI> The changes of average burning rate in experimental conditions were discussed. </LI> </UL> </P>

4세대 오창 원형방사광가속기 소개

원종한(Jonghan Won),윤형중(Hyung Joong Yun),고경태(Kyung-Tae Ko),안득순(Deuk Soon Ahn),이주한(Jouhahn Lee) 대한지질학회 2021 대한지질학회 학술대회 Vol.2021 No.10

빛은 질량이 없는 입자의 흐름으로 보는 입자성과 공간을 통해 전파하는 전자파 특성의 이중성을 가지며 적외선으로부터 경 X-선, 감마선에 이르는 넓은 파장을 아우른다. 방사광가속기는 광범위한 파장 영역의 빛을 인공적으로 만들어 내는 “빛공장”으로 알려져 있다. 방사광가속기는 크게 전자총, 가속기, 저장링, 빔라인으로 구성이 되어져 있으며, 입자충돌용 가속기에서 엑스선을 뽑아 사용한 1세대 방사광가속기, 방사광 발생·사용을 주목적으로 구축된 2세대 방사광가속기, 휨자석(bending magnet) 대신 주기적으로 배열된 자석구조물로 전자빔이 자석배열을 통과하면서 경로를 여러 번 바꿔 더 밝은 방사광을 발생하게 만들어주는 삽입장치(wiggler or undulator)를 사용한 3세대 방사광가속기, 그리고 MBA 격자(multi-bend achromat lattice)를 사용하여 기존의 3세대 보다 전자빔의 에미턴스(빔크기)를 100~1000분의 1 정도 수준으로 줄이고 휘도(밝기) 및 결맞음을 약 100배까지 개선시킨 4세대 방사광가속기로 구분된다. 현재 충청북도 오창에 건설 예정인(2022년~2028년) 다목적 방사광가속기는 전자빔 에너지 4 GeV, 에미턴스 <100 pm·rad의 세계적 수준의 4세대 원형 방사광가속기이다. 총 빔라인 40개 여개를 수용할 수 있으며, 바이오에서 최첨단 신소재까지 다양한 분야를 연구를 할 수 있는 초대형 국가연구 기반시설이 될 것이다. 본 발표에서는 2021년 하반기부터 본격적으로 착수할 다목적 방사광가속기의 기획부터 가속기의 사양 및 활용에 이르는 전반적인 사항을 설명할 예정이다.

Effect of Body Mass Index on Survival in Breast Cancer Patients According to Subtype, Metabolic Syndrome, and Treatment

Cho, Won Kyung,Choi, Doo Ho,Park, Won,Cha, Hyejung,Nam, Seok Jin,Kim, Seok Won,Lee, Jeong Eon,Yu, Jonghan,Im, Young-Hyuck,Ahn, Jin Seok,Park, Yeon Hee,Kim, Ji-Yeon,Ahn, Soohyun Elsevier 2018 Clinical breast cancer Vol.18 No.5

<P><B>Abstract</B></P> <P><B>Purpose</B></P> <P>To investigate the effect of body mass index (BMI) on survival in patients with breast cancer according to tumor subtype, metabolic syndrome, and systemic treatment.</P> <P><B>Patients and Methods</B></P> <P>We identified 5668 patients who underwent curative surgery for breast cancer between 1996 and 2013 from the clinical data of a single institution. Disease-free survival (DFS) and overall survival (OS) were calculated and compared between the patients with BMI ≥ 25 kg/m<SUP>2</SUP> and < 25 kg/m<SUP>2</SUP> in all patients and in specific subgroups, including tumor subtype, metabolic syndrome, and systemic treatment.</P> <P><B>Results</B></P> <P>In all patients, BMI ≥ 25 kg/m<SUP>2</SUP> was an unfavorable factor for OS (<I>P</I> = .030) but not for DFS. In the HR<SUP>+</SUP>/HER2− subgroup, DFS and OS were longer in patients with BMI < 25 kg/m<SUP>2</SUP> than ≥ 25 kg/m<SUP>2</SUP> (<I>P</I> = .012 and .005, respectively). In patients with more than one metabolic syndrome, BMI was an unfavorable factor for OS (hazard ratio, 2.669; <I>P</I> < .001)</P> <P><B>Conclusion</B></P> <P>BMI ≥ 25 kg/m<SUP>2</SUP> was an unfavorable survival factor, particularly in patients with HR<SUP>+</SUP>/HER2− breast cancer.</P>

Suggestion of BRCA1 c.5339T>C (p.L1780P) variant confer from ‘unknown significance’ to ‘Likely pathogenic’ based on clinical evidence in Korea

Ryu, Jai Min,Kang, Goeun,Nam, Seok Jin,Kim, Seok Won,Yu, Jonghan,Lee, Se Kyung,Bae, Soo Youn,Park, Sungmin,Paik, Hyun-June,Kim, Jong-Won,Park, Sung-Shin,Lee, Jeong Eon,Kim, Sung-Won Elsevier 2017 The Breast Vol.33 No.-

<P><B>Abstract</B></P> <P><B>Purpose</B></P> <P>We describe a rationale for the re-classification of the BRCA1 c.5539T>C (L1780P) variant using a clinical evidence.</P> <P><B>Methods</B></P> <P>A retrospective review was conducted to identify all patients with breast or ovarian cancer and the L1780P variant between 2002 and 2015 at a single institution.</P> <P><B>Results</B></P> <P>We identified the BRCA1/2 genetic mutation test results of 1223 breast cancer patients and 174 patients with ovarian cancer. Of the 160 BRCA 1/2 variant unknown significance, 16 (10.0%) patients were identified as having the L1780P variant. Among them, 10 had breast cancer, 4 had ovarian cancer, and 2 had both breast and ovarian cancer. Thirteen (81.3%) patients with this variant had family histories of breast or ovarian cancer. Two (16.7%) also had comorbid ovarian cancer. Two patients with this variant showed that co-segregation of the disease in multiple family members and family histories of breast and ovarian cancer. This variant was found to be either absent or at extremely low frequency in general population databases.</P> <P><B>Conclusion</B></P> <P>The L1780P variant might confer to “Likely pathogenic” according to a clinical evidence and the ACMG standards and guidelines. A nation-wide or global survey and a functional analysis are needed to confirm the pathogenicity of the L1780P variant.</P>

Effect of Retinoic Acidon Fgf-8 Expression in Regenerating Urodele Amphibian Limbs

Man-JongHan,Won-SunKim 한국통합생물학회 2002 Animal cells and systems Vol.6 No.4

Autoignition and combustion characteristics of sodium borohydride-based non-toxic hypergolic fuel droplet at elevated temperatures

Kang, Hongjae,Won, Jonghan,Baek, Seung Wook,Kwon, Sejin Elsevier Science Inc 2017 Combustion and Flame Vol.181 No.-

<P><B>Abstract</B></P> <P>Non-toxic hypergolic propellants have considerably generated recent research interest in the field of green propulsion technology because they can replace highly toxic hypergolic combinations currently used. In this experimental research, sodium borohydride-based non-toxic hypergolic fuel was prepared by blending sodium borohydride in the mixture of energetic hydrocarbon solvents. In a drop test, sodium borohydride as an ignition source enabled the hydrocarbon mixture to initiate hypergolic interactions with H<SUB>2</SUB>O<SUB>2</SUB> oxidizer. Two different heating methods were utilized to analyze the characteristics of autoignition and combustion of the hypergolic fuel. As a reference fuel, a non-hypergolic fuel which has the identical chemical compositions to the hypergolic fuel except for sodium borohydride was tested and compared. As a one of the heating methods, thermogravimetric analysis was not suitable for evaluating the inherent thermophysical properties of the hypergolic fuel. In a droplet combustion chamber test, the autoignition and combustion of the hypergolic fuel droplets occurred exposed to elevated temperatures (in a range of 400–800°C) at atmospheric pressure (1bar), whereas the non-hypergolic fuel droplet was automatically ignited only at 800°C. The ignition delay and total combustion time of the hypergolic fuel droplet were lower than those of the non-hypergolic fuel droplet. According to the temporal histories of the droplet size, sodium borohydride-based hypergolic fuel droplets did not obey the d<SUP>2</SUP>-law of diffusion-controlled combustion, which indicates the droplet evaporation rate was not a controlling factor in the combustion process. Consequently, the addition of sodium borohydride into the hydrocarbon mixture expedited the autoignition and combustion process of the fuel at elevated temperatures.</P>

Evaporation of a single emulsion fuel droplet in elevated temperature and pressure conditions

Kim, Hyemin,Won, Jonghan,Baek, Seung Wook Elsevier 2018 Fuel Vol.226 No.-

<P><B>Abstract</B></P> <P>The evaporation characteristics of water/n-decane emulsion droplet at various temperatures and pressures were experimentally observed. Emulsion fuel was made by adding pure water to the base n-decane fuel with a volume ratio of 0.2. Span 80 was used as a surfactant, and ultrasonification was conducted for the mixing process. The temporal variation of the droplet diameter was optically observed by using a high-speed camera, and the changes in droplet temperature were also measured. The evaporation process of emulsion droplets was divided into three stages, namely, droplet heating, inflation/puffing, and pure evaporation. As the ambient temperature increased, the behavior of droplet inflation shifted to puffing during the inflation/puffing stage. A decline in the inflation/puffing incidence rate was noted at high-pressure conditions. The evaporation rate during the pure evaporation stage and the overall droplet lifetime were affected by the ambient temperature but not by the ambient pressure. The inflation of the droplet mostly occurred at relatively lower temperature and pressure conditions; it changed to puffing, however, at higher temperature and pressure conditions.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Evaporation of a water/n-decane fuel emulsion droplet in various temperature and pressure conditions was studied. </LI> <LI> Changes of evaporation characteristics including droplet inflation and micro-explosion were observed. </LI> <LI> Occurrence of droplet inflation and micro-explosion in various temperature and pressure conditions were discussed. </LI> </UL> </P>

비대면 디지털 경제에 대한 탐색적 연구: 특성, 규제쟁점 및 개선방안을 중심으로

심우현(Shim, Woohyun),원소연(Won, Soh-Yeon),이종한(Lee, Jonghan) 한국지능정보사회진흥원 2022 정보화정책 Vol.29 No.2

급격한 디지털 전환과 코로나19 대유행에 따른 비대면 디지털 경제의 발전은 시장참여자들 간의 이해 충돌, 관련 법·제도의 지체 등 다양한 문제의 해결 필요성을 높이고 있다. 본 연구에서는 비대면 디지털 경제의 정의와 특징을 이론적 고찰을 통해 명확히 하고, 이의 발전을 위해 개선이 필요한 규제쟁점과 개선방안을 뉴스 기사 분석과 전문가 인터뷰를 통해 도출하였다. 이론적 고찰에서는 비대면 디지털 경제가 기존의 디지털 경제가 비대면·비접촉 활동 중심으로 전환되는 과정이며, 초지능화, 초연결화, 초융합화, 초개인화, 초자동화, 초정밀화, 초격차 및 초신뢰라는 여덟 가지 초(超)혁신(8 hypers)의 특성을 지니는 것을 확인하였다. 한편, 뉴스 기사분석과 전문가 인터뷰를 통해 비대면 디지털 경제로의 전환에 따른 기존·신규 사업자의 충돌, 기본권이나 법적 권리 침해, 사회적 가치나 윤리관과의 대립, 시장참여자 간의 갈등, 제도·규제의 부재, 시장 지배력 남용 등과 같은 규제 문제를 확인하고, 이의 해소를 위한 다양한 개선방안을 도출하였다. The radical digital transformation and development of the contactless digital economy in the wake of the COVID-19 pandemic are increasing the need to solve various problems such as conflicts of interest among market participants and delays in related laws and regulations. This study investigates the concept and characteristics of the contactless digital economy and identifies the related regulatory issues and resolutions through literature review, news article analysis, and expert interviews. From the literature review, it is identified that the contactless digital economy has eight hyper-innovation characteristics: hyper-intelligence, hyper-connectivity, hyper-convergence, hyper-personalization, hyper-automation, hyper-precision, hyper-diversity, and hyper-trust. From news article analyses and expert interviews, this study identifies various regulatory issues, such as competition between incumbents and new entrants, the collision of constitutional rights, collision of social values, conflict between market participants, absence of laws and regulations, and existence of excessive market power, and then proposes a series of resolutions.

급속압축장치에서 탄소 나노입자가 첨가된 연료 액적의 증발 및 연소 특성에 관한 실험적 연구

안형진(Hyeongjin Ahn),원종한(Jonghan Won),백승욱(Seungwook Beak),김혜민(Hyemin Kim) 한국연소학회 2015 KOSCOSYMPOSIUM논문집 Vol.2015 No.12