침전제의 종류 및 침전 공정의 변화가 β-Ga₂O₃ 분말 합성에 미치는 영향

황수현,최영종,고정현,김태진,전덕일,조우석,한규성,Hwang, Su Hyun,Choi, Young Jong,Ko, Jeong Hyun,Kim, Tae Jin,Jeon, Deok Il,Cho, Woo Suk,Han, Kyu Sung 한국재료학회 2014 한국재료학회지 Vol.24 No.4

In this research, a precipitation method was used to synthesize ${\beta}-Ga_2O_3$ powders with various particle morphologies and sizes under varying precipitation conditions, such as gallium nitrate concentration, pH, and aging temperature, using ammonium hydroxide and ammonium carbonate as precipitants. The obtained powders were characterized in detail by XRD, SEM, FT-IR, and TG-DSC. From the TG-DSC result, GaOOH phase was transformed to ${\beta}-Ga_2O_3$ at around $742^{\circ}C$, and weight loss percent was about 14 % when $NH_4OH$ was used as a precipitant. Also, ${\beta}-Ga_2O_3$ formed at $749^{\circ}C$ and weight loss percent was about 15 % when $(NH)_2CO_3$ was used as a precipitant. XRD results showed that the obtained $Ga_2O_3$ had pure monoclinic phase in both cases. When $(NH)_2CO_3$ was used as a precipitant, the particle shape changed and became irregular. The range of particle size was about $500nm-4{\mu}m$ based on various concentrations of gallium nitrate solution with $NH_4OH$. The particle size was increased from $1-2{\mu}m$ to $3-4{\mu}m$ and particle shape was changed from spherical to bar type by increasing aging temperature over $80^{\circ}C$.

이산화탄소 포집능 향상을 위한 활성탄소 섬유 흡착제 제조

황수현(Su-Hyun Hwang),박현수(Hyun-Soo Park),김동우(Dong-woo Kim),조영민(Young-Min Jo) 한국대기환경학회 2015 한국대기환경학회지 Vol.31 No.6

50대 이상 성인의 저작불편감이 골관절염 유병에 미치는 영향

황수현 ( Su Hyun Hwang ),한삼성 ( Sam Sung Han ),유왕근 ( Wang Keun Yoo ) 한국치위생과학회 2015 치위생과학회지 Vol.15 No.2

In this study, PASW Statistics ver. 18.0 was used to analyze the correlation between chewing difficulty and osteoarthritis in the population of 8,498 persons aged 50 years and older who had completed the health related questionnaire in the fifth Korea National Health and Nutrition Examination Survey in 2010∼2012. The following conclusion was drawn: The distribution of the chewing difficulty status showed that 38.8% of the respondents had chewing difficulty and that there was no significant difference by gender. Older respondents tended to have significantly greater chewing difficulty 34.3% of the respondents aged from 50 to 64 years and 46.4% of those aged 65 years and older, those who had lower levels of education and income, who were smokers, and who had higher levels of depression and stress suffered from significantly greater chewing difficulty. Chewing difficulty and osteoarthritis were correlated with each other: the respondents having chewing difficulty had 1.44 (95% confidence interval [CI], 1.23∼1.70) higher prevalence of osteoarthritis than those with no such difficulty. In addition, such correlation was not found in males: the former had 1.36 (95% CI, 0.98∼1.88) higher prevalence of osteoarthritis than the latter, which was not statistically significant. Such correlation was found in females: the former had 1.47 (95% CI, 1.22∼1.76) higher prevalence of osteoarthritis than the latter, which was statistically significant. Therefore, the chewing difficulty status affected osteoarthritis for females aged 50 years and older. Therefore, the efforts to solve oral health problems through oral hygiene would help prevent osteoarthritis from worsening and manage the condition.

광중합형 임시충전재의 미세누출에 관한 실험연구

황수현 ( Su Hyun Hwang ),유지수 ( Ji Su Yu ),김선주 ( Sun Ju Kim ) 한국치위생과학회 2011 치위생과학회지 Vol.11 No.4

The purpose of this experiment was to examine possibility of microleakage by water, temperature change, and bite force inside the mouth during the period of using light-activated temporary filling materials. 2 kinds of light-activated temporary filling materials were used in order to measure weight and compressive strength and to evaluate microleakage between filling material and cavity wall according to frequency of thermal circulation. First, Light-activated temporary filling material was increased the weight, which was measured according to the period of using. As for the result of comparing between products, the weight of Quicks was indicated to be higher. Second, Compressive strength of Spacer had significant difference depending on period of using. However, significant difference wasn`t shown in the compressive strength of Quicks. In Spacer that showed significant difference, the compressive strength increased greatly in the difference of 3 days. Third. As for micro-leakage according to frequency of thermal circulation, the microleakage was indicated to be the highest in the group that carried out 7,000 times. The group with operation of 1,000 times and the group with operation of 3,000 times were indicated the statistically lower micro-leakage than the group with operation of 7,000 times. This study brought about a rise in micro-leakage depending on the passage in the period of using. However, it is obvious fact that micro-leakage increases according to the passage of time after restoration.

저농도 이산화탄소 포집용 활성탄소섬유 흡착제의 질소작용기 함침연구

황수현(Su-Hyun Hwang),김동우(Dong-Woo Kim),정동원(Dong-Won Jung),조영민(Young-Min Jo) 한국대기환경학회 2016 한국대기환경학회지 Vol.32 No.2

불소도포제에 의한 치면열구전색제의 마모저항성과 표면 변화에 관한 실험연구

황수현 ( Su Hyun Hwang ),유지수 ( Ji Su Yu ) 한국치위생과학회 2010 치위생과학회지 Vol.10 No.5

노인의 만성질환, 구강건강행태와 치주질환의 관련성

황수현(Su-hyun Hwang),유지수(Ji-su Yu) 한국산학기술학회 2024 한국산학기술학회논문지 Vol.25 No.5

본 연구는 노인의 만성질환, 구강건강행태가 치주질환의 관련성을 분석하여 노인의 구강건강 증진을 위한 기초자료를 제공하고자 시행되었다. 자료 수집은 건강지표를 대표할 수 있는 국민건강영양조사 제7기(2016-2018) 원시자료를 활용하여 만 65세 이상이면서 치주질환 구강검진에 참여한 2,705명을 최종대상자로 선정하였고, SPSS Ver. 29.0 프로그램으로 복합표본 분석을 하였다. 연구결과, 치주질환에 영향을 미치는 요인은 남자는 여자보다 1.45배, 당뇨병군은 정상보다 1.36배 치주질환 위험도를 나타냈다. 비만군은 1.28배, 흡연자는 1.54배, 구강검진을 받지 않은 군은 1.28배 치주질환 위험도가 더 높게 나타났다. 1일 칫솔질의 횟수는 1회 이하인 경우가 3회 이상인 경우보다 1.29배 치주질환 위험도가 더 높게 나타났다. 결론적으로, 노인의 만성질환, 구강건강행태와 치주질환과의 관련성은 매우 밀접한 관련이 있는 것을 확인할 수 있었으며, 지속적으로 증가하는 노인의 건강한 노년기를 위해 노인을 대상으로 한 맞춤형 구강건강관리 프로그램을 개발하고, 계속적이며 체계화된 예방프로그램 운영이 필요할 것으로 사료된다. This study sought to provide basic data for improving the oral health of the elderly by analyzing the relationship between chronic diseases, the oral health behaviors of the elderly, and periodontal disease. These factors were analyzed using the data from 2,705 people aged 65 years or older who participated in oral examinations for periodontal diseases in Koreas 7th National Health and Nutrition Survey (2016-2018). Data were analyzed using SPSS Ver. 29.0. The results showed that the factors affecting periodontal disease were 1.45 times higher for men than for women and the diabetic groups had a 1.36-fold higher risk of periodontal disease. Obese groups had a 1.28-fold, smokers had a 1.54-fold, and those who did not undergo oral examination had a 1.28-fold higher risk of periodontal disease than those who brushed their teeth 3 or more times or less per day. In conclusion, to enhance health in old age, it is considered necessary to develop customized oral health care programs for them and to conduct continuous and systematic periodontal disease prevention programs.

존 맥그라스 연극의 정치성

황수현(Hwang, Su-Hyun) 한국현대영미드라마학회 2017 현대영미드라마 Vol.30 No.1

고효율 및 고출력 태양광 모듈을 위한 셀 스트링 연구

박지수,황수현,오원제,이수호,정채환,이재형,Park, Ji Su,Hwang, Soo Hyun,Oh, Won Je,Lee, Su Ho,Jeong, Chae Hwan,Lee, Jae Hyeong 한국전기전자재료학회 2018 전기전자재료학회논문지 Vol.31 No.5

In this work, we conducted a study on cell strings of high efficiency and high power solar cell modules via simulation. In contrast to the conventional module manufacturing method, the simulation was performed by connecting cutting cells divided into four parts from 6-in size using the electrically conductive adhesive (ECA). The resistance of the ECA added in series connection was extracted using an experimental method. This resistance was found to be $3m{\Omega}$. Based on this simulation, we verified the change in efficiency of the string as a function of the number of cutting cell connections. Consequently, the cutting cell efficiency of the first 20.08% was significantly increased to 20.63% until the fifth connection; however, for further connections, it was confirmed that the efficiency was saturated to 20.8%. Connecting cutting cells using ECA improves the efficiency of the string; therefore, it is expected that it will be possible to fabricate modules with high efficiency and high power.

전해채취에 의한 Gallium의 정제기술

최영종,황수현,전덕일,한규성,Choi, Young-Jong,Hwang, Su-Hyun,Jeon, Deok-Il,Han, Kyu-Sung 한국자원리싸이클링학회 2014 資源 리싸이클링 Vol.23 No.6

갈륨은 주로 산화물 반도체용 타겟이나 LED 칩을 만드는 중요한 소재로 사용하고 있는데 아직까지 폐기물로부터 재자원화에 의한 순환량이 매우 낮다. 이로 인해 갈륨을 함유하고 있는 대부분의 폐자원은 해외로 유출되고 원재료는 수입에 의존하고 있다. 따라서 희유금속인 갈륨을 함유하고 있는 저품위 갈륨으로부터 갈륨을 회수하여 고순도화하는 방법을 연구 하였다. 전처리 과정으로 스크랩을 미분쇄하여 산으로 침출하였다. 침출액내 인듐은 치환으로 석출시켜 분리한 후 알칼리를 사용하여 갈륨과 아연을 수산화물로 침전시켜 여과 분리하였다. 갈륨과 아연수산화물을 알칼리용액으로 침출시켜 전해액을 제조하였고 전해채취로 갈륨과 아연메탈을 회수하였다. 갈륨과 아연은 진공정제를 통하여 아연을 제거하고 고순도의 갈륨을 회수하였다. Gallium is an important material and is used by industry of oxide semi-conductor and LED chip. However, the most of the gallium-containing waste resources became outflow abroad and the most of which is imported from oversea by following technical problem and low circulation rate. In this research, the recovery of high purity Gallium metal from Gallium scrap, which containing about 30% of Gallium, was investigated by using hydro-metallurgical process. As pretreatment, the Gallium scrap was pulverized and leached by strong acid such as hydro chloric acid. At the leached solution, Indium was separated as an Indium sponge by substitution reaction and then Gallium and Zinc hydroxide separated and filtrated using strong alkaline solution such as sodium hydroxide by precipitation method. Also, Gallium metal and Zinc metal was recovered by electrowinning method. To make an electrolytic solution, Gallium and Zinc hydroxide was leached by strong alkaline solution. Finally, High purity Gallium metal was recovered by vacuum refining process to remove the Zinc impurity.