그래핀에 담지된 Fe₃O₄와 CuO 나노입자의 리튬이차전지 음극성능

정재훈,정동원,한상욱,김광현,오은석,Jeong, Jae-Hun,Jung, Dong-Won,Han, Sang-Wook,Kim, Kwang-Hyun,Oh, Eun-Suok 한국전기화학회 2011 한국전기화학회지 Vol.14 No.4

본 연구에서는 에틸렌글리콜을 사용한 polyol reduction 방법으로 나노크기의 $Fe_3O_4$와 CuO가 각각 그래핀에 분산된 $Fe_3O_4$/graphene, CuO/graphene 복합체를 합성하였으며, 이를 리튬이차전지의 음극활물질로 사용한 전극의 성능을 평가하였다. 합성된 복합체의 물리적 특성은 SEM, XRD, TGA 등으로 분석하였으며, 반쪽전지를 제조하여 충/방전, cyclic voltammetry, 교류 임피던스 등의 전기화학적 특성평가를 수행하였다. 그래핀 표면에 분산된 금속산화물 나노입자들에 의한 용량증가 및 전기적 네트워크 향상 등의 효과로 $Fe_3O_4$/graphene 및 CuO/graphene 복합체의 전극성능이 그래핀 전극보다 우수하였다. 복합체의 경우 30회 충/방전 후에도 600 mAh/g 용량을 유지하였다. In this study, $Fe_3O_4$/graphene and CuO/graphene composites were synthesized by the polyol reduction method using ethylene glycol, and their performances as the anodes of lithium ion batteries were evaluated. The physical characteristics of the synthesized composites were analyzed by SEM, XRD, and TGA. In addition, their electrochemical properties were examined by the electrochemical analysis techniques such as charge/discharge performance, cyclic voltammetry, and AC impedance spectroscopy. The cells composed of $Fe_3O_4$/graphene and CuO/graphene composites showed better performance than the graphene electrode, due to the dispersion of nanosized $Fe_3O_4$ or CuO on the surface of graphene and the formation of good electrical network in the electrode. Their composites kept the reversible capacity more than 600 mAh/g even after the charging/discharging of 30 cycles.

안와 상벽 골절과 광대뼈 골절의 임상 양상과 치료 및 동반된 안과적 진단

정재훈,이화,이종미,백세현,Jae Hoon Jung,Hwa Lee,Jongmi Lee,Sehyun Baek 대한안과학회 2012 대한안과학회지 Vol.53 No.4

Purpose: To investigate the clinical manifestations, management, and ophthalmologic complications of orbital roof fractures and zygoma fractures. Methods: A retrospective survey of 119 patients who visited Korea University Medical Center from June 2009 to June 2010 was performed. The sex, age, causes, fracture characteristics, neurologic injury, ocular injury, and combined facial bone fractures of patients who were diagnosed with orbital roof fracture and zygoma fracture were statistically analyzed. Results: The mean age of patients with orbital roof fracture was 33.0 years old. The most common cause of orbital roof fracture was traffic accident (36.1%) with 6 patients receiveing surgical treatement (9.8%). Among the ophthalmologic diagnoses of the patients with orbital roof fracture, traumatic iridocyclitis was the most common (7 eyes) followed by eyeball rupture (2 eyes). The mean age of patients with zygoma fracture was 36.6 years old. The most common cause of zygoma fracture was traffic accident (32.8%), with 51 patients receiving surgical treatement (87.9%). Among the ophthalmologic diagnoses of the patients with zygoma fracture, traumatic iridocyclitis was the most common (6 eyes), followed by commotio retina (4 eyes). Conclusions: The present study regarding clinical characteristics and treatment of orbital roof fracture and zygoma fracture is helpful for ophthalmologists regarding the treatment of accompanying ophthalmologic complications. J Korean Ophthalmol Soc 2012;53(4):577-581

개화기 사과 '후지'와 '홍로'의 품종간 저온 피해율, 호르몬과 유리당 분석

정재훈,한점화,류수현,조정건,이슬기,Jeong, Jae Hoon,Han, Jeom Hwa,Ryu, Suhyun,Cho, Jung Gun,Lee, Seul-Ki 한국생물환경조절학회 2021 생물환경조절학회지 Vol.30 No.4

최근 지구온난화에 의한 이상기상으로 겨울철 한파와 봄철 저온에 의한 농작물 피해가 심각하게 발생하고 있다. 특히 과수의 개화기 저온피해는 꽃눈의 생육단계에 따라 차이가 있으며 발육이 진전될수록 내한성이 약해져 개화 직전부터 낙화 후 1주까지 한계온도가 다르게 발생한다. 따라서 개화기가 빠른 사과 '홍로'가 '후지'보다 피해가 심각한 것이 일반적이나 2020년 4월 저온피해는 개화기가 늦은 '후지'의 피해가 심하게 발생하여그 원인을 분석하고자 본 연구를 수행하였다. 충북 보은군 사과나무 '후지'와 '홍로'를 동시에 재배하는 2농가를 대상으로 품종 간 피해율 실태조사를 실시하였다. 또한 정확한 품종 간 비교 분석을 위하여 생육단계가 동일한 시료를 선택하여 인위적으로 저온처리(-2.0℃, -4.0℃)를 하여 피해 정도를 조사하고, 원인 분석을 위해 조직 내 유리당과 호르몬 함량을 분석하였다. 실태조사 결과 2농가 모두 '후지'가 '홍로'보다 피해율이 높았으며, 특히 B농가(저지대, 평지) '후지'의 경우 피해율이 60.5%로 가장 높았다. 또한 동일한 생육단계의 시료를 사용한 인위적 저온 처리 시험결과에서도 '후지'와 '홍로' 품종 간 피해율에 유의한 차이가 있었다. 유리당 함량은 저온 피해율이 낮았던 '홍로'가'후지'보다 높았으며, 호르몬 분석 결과 정상 꽃눈보다 손상된 조직에서 ABA, IAA와 SA 함량이 높게 나타났다. 따라서 본 연구 결과 조직내 유리당 함량이 높으면 저온 피해율이 낮은 것을 확인할 수 있었으며, 특히 저온 피해율은 sorbitol 함량과 부의 상관관계를 이루고 있다. Freezing damage to fruit trees is frequently occurring due to cold in winter and low temperature in spring to abnormal weather caused by global warming. In particular, the freezing injury of deciduous fruit trees is highly dependent on the developmental stages of the flower buds. And the cold resistance is weakened as the growth progresses, so it is most vulnerable period from flowering to petal fall(post-bloom). Therefore, this study was conducted to analyze the cause of the freezing injury caused by severe low temperature to 'Fuji', which has a late flowering period more than 'Hongro' in April 2020. We investigated freezing injury rate in 'Fuji' and 'Hongro' apple trees damaged by natural low temperature at Boeun-gun, Chungbuk province in Korea. In addition, flower buds in the same developmental stage (tight cluster) were treated artificially low temperature to investigate the injury rate for accurate comparative analysis between varieties, and to analyze the soluble sugar and hormone contents in the flower buds. As a result of survey in natural low temperature, 'Fuji' had a higher injury rate than 'Hongro' in both orchards, and in particular, B orchard 'Fuji' had the highest injury rate of 60.5%. Also there were significantly difference in the freezing injury rate between 'Fuji' and 'Hongro' in artificially low temperature treatments. As a result of analyzing the soluble sugar contents in 'Hongro' was higher than 'Fuji'. Also ABA, IAA and SA contents were more increased in the damaged tissue than in the normal flower buds by low temperature treatments. Consequently, it was assumed that the freezing injury was closely related to soluble sugar contents in the flower buds. In particular, the freezing injury rate was negatively correlated with the sorbitol contents.

조절 가능한 온도감도를 지닌 광섬유격자 온도센서

정재훈,남희,이병호,Jung, Jae-Hoon,Nam, Hui,Lee, Byoung-Ho 대한전자공학회 1999 電子工學會論文誌, D Vol.d36 No.9

온도 팽창률이 다른 두 개의 금속을 광섬유 브래그 격자에 부착하여 그 온도감도를 조절할 수 있는 새로운 온도센서를 제안하였다. 이러한 방법으로 온도감도를 기존의 브래그격자에 비해 3.3까지 향상시켰으며 금속의 길이를 변화시켜 그 온도감도를 여러 가지로 조절할 수 있었다. By attaching two metals with different thermal expansion coefficients to a fiber Bragg grating, we show that the temperature sensitivity is successfully improved to 3.3 times that of bare fiber Bragg grating and controlled by changing the metal length.

Arrayed Waveguide Grating의 스펙트럼해석

정재훈,Jung, Jae-Hoon 한국전기전자학회 2004 전기전자학회논문지 Vol.8 No.1

Arrayed waveguide grating의 스펙트럼을 해석하기 위해 Fresnel Kirchhoff diffraction 식과 Fraunhofer diffraction 근사식을 이용하여 실제로 제작되는 16채널 및 40채널의 arrayed waveguide grating에 대해 적용해 보았으며 Fraunhofer diffraction 근사식을 적용할 때 생기는 문제점을 모델별로 도출하였고 그 오차를 실제의 공정오차와 비교하였다. We performed the spectrum analysis of arrayed waveguide grating using Fresnel Kirchhoff diffraction formula and its approximated Fraunhofer diffraction equation and applied both methods to 16 channel and 40 channel models. We presented the spectra and found out the limitations of Fraunhofer diffraction in analysis of arrayed waveguide grating and compared the errors coming from Fraunhofer diffraction approximation and due to imperfection during the fabrication process.

Fruit Quality of 1-Methylcyclopropene Treated 'Formosa' Plum on the Shelf Life at Ambient Temperature

정재훈,김영칠,정석규,Jung, Jae-Hoon,Kim, Young-Chil,Jung, Seok-Kyu Korean Society of Horticultural Science 2010 원예과학기술지 Vol.28 No.3

The effects of 1-methylcyclopropene (1-MCP) for controlling ripening processes such as weight loss, fruit softening, soluble solids content (SSC), titratable acidity (TA), and fruit skin color were investigated and also the possibility that 1-MCP can inhibit the development of brown rot was explored in 'Formosa' plum ($Prunus$ $domestica$ L.). Fruit were treated with $1{\mu}L{\cdot}L^{-1}$ 1-MCP on the day of harvest and one day after harvest for 16 h at ambient temperature ($20^{\circ}C$), followed by 14 days of shelf life. 1-MCP treatment delayed fruit softening, weight loss and changes in skin color and TA during the shelf life period, but did not affect SSC. These 1-MCP effects were similar with and without delayed treatment. 1-MCP treatment inhibited the development of brown rot caused by $Monilinia$ $laxa$ during storage. Our data shows that treatment delays of ${\geq}1$ day before 1-MCP application had no negative effect of fruit softening, fruit skin color, and TA at ambient temperature ($20^{\circ}C$). Overall, these results indicate that 1-MCP can be used to maintain the quality of non-refrigerated plums. 본 연구는 1-MCP가 'Formosa' 자두의 저장 중 품질 변화와 유통기간 연장에 미치는 효과를 밝히고자 수행하였다. 수확한 'Formosa' 자두를 균일한 크기와 색깔로 선별한 후 수확 당일 그리고 수확 후 1일 후에 걸쳐서 각각 1-MCP를 $1{\mu}L{\cdot}L^{-1}$ 농도로 $20^{\circ}C$에서 16시간 동안 처리하여 대조구(무처리)와 비교하였다. 1-MCP를 처리한 후 14일 동안 상온에서 자두의 연화도, 과중감소율, 가용성고형물 함량 변화, 산도, 그리고 과실의 색깔 변화를 측정하였다. 과중감소율과 과실연화도는 1-MCP 처리구가 무처리구에 비해서 적은 변화폭을 보여주었다. 1-MCP 처리 시기(수확당일 그리고 수확 후 1일) 간에는 따른 큰 차이는 없었다. 가용성고형물 함량에는 통계적 유의성은 없었으나, 1-MCP처리구의 과실에서는 산도와 과실의 색깔 변화가 무처리구에 비해서 적게 나타났다. 또한 1-MCP는 저장 중에 발생하는 과실의 부패병 억제효과를 나타내었다. 따라서 본 연구결과, 1-MCP 처리시기(${\geq}1$일) 연장은 상온저장시 과실의 경도, 산도, 과일 색깔 변화에 큰 영향을 미치지 않았으며, 또한 과실품질 유지에 실용성이 있는 결과를 보여주었다.

한국 성인에서 주관적 인지저하를 동반한 우울증의 특성과 삶의 질 : 제 7기 국민건강영양조사를 중심으로

정재훈,김성진,정도운,문정준,전동욱,김연수,최현석,이민주,전경수,Jeong, Jae-Hoon,Kim, Sung-Jin,Jung, Do-Un,Moon, Jung-Joon,Jeon, Dong-Wook,Kim, Yeon-Sue,Choi, Hyeon-Seok,Lee, Min-Joo,Jeon, Gyeong-Su 한국정신신체의학회 2021 정신신체의학 Vol.29 No.1

Objectives : This study aimed to investigate quality of life, severity of depression, suicidality, subjective health and subjective stress of depression with subjective cognitive decline in Korean adults. Methods : We used the 7th KNHANES data to enroll 415 participants with a score of 10 or higher on Patient Health Questionnaire-9 (PHQ-9), aged 20-64. Depression was divided into two groups based on the presence/absence of subjective cognitive decline. Demographic and psychological characteristics were compared between two groups. Correlation analysis of subjective cognitive decline, quality of life, depression, suicidal idea was carried out. To detect which variables influenced quality of life, a multiple regression analysis was carried out. Results : Among the 415 participants, 98 had depression with subjective cognitive decline. We identified significant differences in age, marital status, education, employment between the two groups. After adjusting for these variables, depression with subjective cognitive decline had lower EuroQol-5D index scores, more severe depressive symptoms without cognition and worse subjective health than depression without cognitive decline. There was a significant correlation between subjective cognitive decline and quality of life (r=-0.236, p<0.001), suicidal idea (r=0.182, p<0.001), depression score without cognition (r=0.108, p=0.028). Through multiple regression analysis, subjective cognitive decline was predictor of reduced quality of life (β=-0.178, p<0.001). Conclusions : Depression with subjective cognitive decline has poor quality of life and severe depression. Cognitive decline should be considered to improve treatment result in depression. 연구목적 국내의 성인을 대상으로 주관적 인지 저하를 동반한 우울증에서 삶의 질, 우울의 심각도, 자살 관련 특성, 주관적 건강 상태 및 스트레스 인지에 대해 조사하고자 하였다. 방 법 국민건강영양조사 제 7기 자료를 이용하여 Patient Health Questionnaire (PHQ-9)에서 10점 이상인 인구 415명을 대상으로 하였다. 주관적 인지 저하 유무에 따라 두 군의 특성 차이를 비교했다. 주관적 인지 저하와 삶의 질, 우울, 자살사고의 상관성을 보기 위해 상관분석 및 회귀 분석을 실시했다. 결 과 주관적 인지 저하를 동반한 우울증 집단이 삶의 질과 주관적 건강이 더 좋지 않았고 우울의 심각도가 심했다. 주관적 인지 저하와 삶의 질은 음의 상관관계, 자살사고와 우울은 양의 상관관계를 보였다. 회귀 분석을 통해 주관적 인지 저하가 삶의 질에 부정적 영향을 미치는 것을 확인했다. 결 론 주관적 인지 저하를 동반한 우울증은 삶의 질을 저해하고 우울의 심각도가 심하며 삶의 질, 자살사고 및 우울을 악화시키는 것으로 확인되었다.

수종(數種)의 한약재의 Tyrosinase와 Elastase 활성 억제 효과에 대한 실험적 연구

정재훈,김경준,Jung, Jae-Hoon,Kim, Kyung-Jun 대한한방안이비인후피부과학회 2009 한방안이비인후피부과학회지 Vol.22 No.2

Objectives : The purpose of this study is to investigate whitening effects and anti-wrinkle effects of a few 80% ethanol extracted herbal medicines. Methods : In the first study, a few 80% ethanol extracted herbal medicines were screened for their inhibitory activities against the tyrosinase. In the second study, a few 80% ethanol extracted herbal medicines were screened for their inhibitory activities against elastase. Results : 1. We showed 28%, 27% and 19% inhibitions of mushroom tyrosinase at 500 $\mu$g/ml concentration of ASR, AIF and ABR extracts and they were showed higher anti-tyrosinase activity than arbutin's. We also could observe that the decreased mushroom tyrosinase activities in RR, CML, LR, AGR and TH extracts. 2. RR, AF and ABR (final concentrstion 1 mg/ml) were appeared 60%, 98%, 83% of inhibitions of elastase activity, and they were showed higher anti-elastase activity than that of ursolic acid. We also could observe that the decreased elastase activities in AIF, AR, LR and CML extracts. Conclusions : These results suggest that ASR, AIF and ABR extracts contribute to the anti-melanin activities and represent potential sources of whitening agent, and RR, AF and ABR extracts contribute to the anti-elastase activities and represent potential sources of anti-wrinkle agent. These results suggest that some herbal medicines could be strong potential sources of inhibition about anti-aging and whitening effects for the skin.

광섬유 표면 플라즈몬 공명 센서를 이용한 스트레인 및 온도 측정

정재훈,김민욱,Jung, Jae-Hoon,Kim, Min-Wook 한국전기전자학회 2007 전기전자학회논문지 Vol.11 No.2

본 논문에서는 광섬유 표면 플라즈몬 공명 센서를 이용하여 스트레인 및 온도 변화에 따른 센서를 제시하였다. 광섬유 센서의 구조는 광섬유의 클래딩 일부를 제거하여 크롬, 은, 금을 증착한 다층 박막 구조를 모델로 하였고, dip 파장의 변화가 선형성을 보임으로써 효율적인 센서로의 활용 가능성을 보이고자 한다. This paper decribess the strain and temperature sensor using fiber optic surface plasmon resonance sensor. The sensor head is 3-layered, Cr, Ag, Au and we showed feasibility to use this sensor to measure strain and temperature.

플라스틱 기판을 이용한 고분자 청색 유기발광다이오드의 발광 특성

정재훈,문대규,Jung, Jae-Hoon,Moon, Dae-Gyu 한국전기전자재료학회 2013 전기전자재료학회논문지 Vol.26 No.9

We have fabricated blue phosphorescent organic light-emitting devices (OLEDs) on a plastic substrate. The solution coated poly (9-vinylcarbazole) (PVK) host doped with Bis (3,5-difluoro-2-(2-pyridyl)phenyl_(2-carboxypyridyl)irdium(III) (FIrPic) guest molecules was used as an hole transporting emission layer. The device structure was ITO/PVK:FIrpic (50 nm, xwt%)/TAZ 50 nm)/LiF (0.5 nm)/Al (100 nm). The concentration of FIrpic molecule was varied from 1 wt% to 10 wt%. The OLED on plastic substrate exhibited maximum current efficiency of 18 cd/A with 5 wt% FIrpic molecules were doped into the PVK layer.