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실리콘 카바이드 쇼트키 다이오드에서 역방향 항복전압의 개선을 위한 구조 설계
이용재,정희종 동의대학교 산업기술개발연구소 2006 産業技術硏究誌 Vol.20 No.-
초고내압의 소자제작을 위해서 기존의 실리콘 재질 대신에 물질은 탄화규소(4H-SiC)이며, 기판은 에피층의 두께 12㎛, 농도 5×10^(15)cm^(-3)의 드리프트 층의 웨이퍼이다. 탄화규소( 4H-SiC) 기판에 접합 장벽 쇼트키 다이오드를 설계 제작하였다. 역방향 항복전압 특성을 개선시키기 위해서, 구조적으로 쇼트키 활성영역 내에 보호테의 폭 3㎛를 갖는 P^(+)형 영역을 설계하였으며, 공정은 이온주입 공정을 통해 알루미늄을 확산 형성하였다. 설계 및 제작한 소자의 온-상태 전압이 1.26V, 온-상태 저항은 45㏁/㎠이며, 개선된 역방향 항복전압은 1,260V의 최대값이며, 이 항복 전압의 역방향 누설전류 밀도는 2.26×10^(-5)A/㎠으로 비교적 낮은값으로 항복전압과 누설전류 밀도의 개선이 이루어졌다.
한국산 인삼의 Polyphenol 분획물의 항산화, Phospholipase A2 및 암세포증식 억제효과
최희진 ( Choe Hui Jin ),한호석 ( Han Ho Seog ),박정혜 ( Park Jeong Hye ),손준호 ( Son Jun Ho ),배종호 ( Bae Jong Ho ),성태수 ( Seong Tae Su ),최청 ( Choe Cheong ) 한국응용생명화학회 2003 Applied Biological Chemistry (Appl Biol Chem) Vol.46 No.3
The polyphenol fractions of Korean ginseng were purified using Sephadex LH-20, MCI gel, Bondapak C_(18), TLC, and HPLC from the 60% acetone soluble fraction. Fraction I showed 48.16%, 79.71% and 43.55% inhibition at 150 ppm against lipid oxidation in the presence of copper ion, superoxide and hydrogen peroxidation. Electron donating abilities of fraction Ⅱ showed 35.17% inhibition at 200 ppm. Fraction Ⅲ showed 48.49% and 25% inhibition at 150 ppm against lipid oxidation in the presence of ferrous ion and hydroxy radical ion. The phospholipase A₂ inhibitory effect of fraction Ⅲ was 48.9% at the concentration of 60 ㎍/m/. The cytotoxic effects of fraction Ⅱ was the highest (73.29% at 0.25 ㎎/m/) among the tested polyphenol fractions.
이희주(Lee, Hui Ju),신현기(Shin, Hyunki),정종원(Cheong, Jong One) 서울행정학회 2021 한국사회와 행정연구 Vol.31 No.4
기존 정책을 개선하고, 효과성을 높이려는 목적에서 이루어지는 정책변동에도 불구하고 예측한 효과가 나타나지 않는 경우가 많다. 본 연구는 저출산 관련 정책변동이 얼마나 효과가 있었는지 분석하고자 했다. 2016년 시행된 제3차 저출산・고령사회 기본계획은 저출산 문제에 대한 ‘사회구조적 대응’이라는 목표 아래, 다양한 정책변동을 시도했는데, 이러한 정책변동의 효과를 검증하는 것은 국가적 과제인 저출산 문제의 해결에 필수적이다. 본 연구는 ‘제3차 저출산・고령사회 기본계획의 도입’이라는 정책변동이 22~42세 여성의 출산의향에 어떠한 영향을 미쳤는지를 포아송 회귀분석 방법으로 분석했다. 분석 자료는 한국보건사회연구원의 ‘전국 출산력 및 가족보건실태조사’ 데이터였다. 분석결과, 정책변동 이후 오히려 이상자녀수가 통계적으로 유의하게 감소했다. 또한 현재 자녀가 있는지 여부에 따라 여성의 출산의향에 영향을 미치는 요인들의 영향력이 다르게 나타났다. 이는 청년들의 결혼 선택, 결혼한 무자녀 여성들의 신규 출산 선택, 결혼한 유자녀 여성들의 추가 출산 선택 등 결혼-출산-양육으로 이어지는 여성의 생애주기에 조응하는 맞춤형 정책 개발이 필요함을 시사한다. Although policy changes would improve existing policies and increase their effectiveness, the expected effects may not been realized. This study is to analyze how the changes in the low fertility policy in Korea were effective. The 3rd Basic Policy Plan for Low Birthrate and Aging Society implemented in 2016 has attempted various policy changes under the goal of ‘responding to the social structure’ of the declining birthrate. Verifying the effects of the policy changes is necessary to solve the problem of declining birthrate, which is a national policy issue. In this study, we analyzed how the policy changes by ‘execution of the Third Basic Plan for Aging Society with a Declining Birthrate’ affected women aged 22 to 42 years old employing the Poisson regression analysis. The analyses were based on the data from ‘National Survey of Fertility and Family Health’ collected by the Korea Institute of Health and Social Affairs (KIH). As results of the analyses, changes in the birthrate policy have significantly reduced the ideal number of children. In addition, the influence of factors affecting women’s willingness to give birth differed depending on whether or not they currently have children. This requires the development of tailored public policies with consideration of the life cycle of women who lead to marriage, childbirth, and parenting including choice of marriage of young people, birth choice of married women without children, and choice of additional childbirth of married women with a child or children.
Bahng, Wook,Cheong, Hui Jong,Kang, In Ho,Kim, Seong Jin,Kim, Sang Cheol,Joo, Sung Jae,Kim, Nam Kyun Trans Tech Publications, Ltd. 2007 Materials science forum Vol.556 No.-
<P>We have investigated the influence of surface modification on the electrical properties of SiC diodes. Schottky diodes (SBDs) as well as PiN diodes were fabricated on n-type SiC substrate with an epilayer, and electrically characterized before and after high temperature annealing, and after removing the surface modified layer, respectively. The devices annealed without graphite cap layer showed ohmic behavior. The surface layer was modified to a conductive layer possibly due to the preferred sublimation of Si species. In order to confirm the existence of modified surface conductive layer, diode was fabricated on the same substrate and electrically characterized after removing 30nm-thick damaged layer by ICP-RIE. The leakage current reduced dramatically, as much as 7 orders of magnitude. The PiN diodes fabricated on the damaged surface layer showed the reverse leakage current and the breakdown voltage of 50mA and 1250V, respectively. While those of the diode fabricated after removing the damaged surface layer were 200nA at the breakdown voltage of 2100V, respectively.</P>
이상희 ( Lee Sang Hui ),김종석 ( Kim Jong Seog ),김청미 ( Kim Cheong Mi ),김보욱 ( Kim Bo Ug ),황주연 ( Hwang Ju Yeon ),조희영 ( Jo Hui Yeong ),김두표 ( Kim Du Pyo ),이윤호 ( Lee Yun Ho ) 대한산부인과학회 2004 Obstetrics & Gynecology Science Vol.47 No.5
In prenatal diagnosis of neural tube defects, maternal serum α-fetoprotein (MSAFP) level in second trimester is used as a screening test. However, it shows low sensitivity with high false positive rate. Also, α-fetoprotein and acetylcholinesterase in amniotic fluid through amniocentesis is used, but it is an invasive technique with low sensitivity. Recently, due to improved prenatal sonography, typical sonographic findings of spina bifida are reported and contributed to early diagnosis and detection of possible co-existing abnormalities. We report a case of spina bifida detected at 21 weeks of pregnancy by prenatal sonograph at our institution with a brief review of literature.
새로운 전계 제한테 구조를 갖는 탄화규소 기판의 쇼트키 다이오드의 제작과 특성 분석
정희종,한대현,이용재,Cheong Hui-Jong,Han Dae-Hyun,Lee Yong-Jae 한국정보통신학회 2006 한국정보통신학회논문지 Vol.10 No.7
초고내압용 (1,200 V급) 의 플래너 접합 장벽 쇼트키 정류기 개발을 위해서 기존의 실리콘 재질 대신에 탄화규소 (4H-SiC) 제질을 사용하였다 . 기판의 크기는 2 인치 웨이퍼이며, 농도는 $3*10^{18}/cm^{3}$의 $n^{+}-$형이며, 에피층은 두께 $12{\mu}m$, 농도는 $5*10^{15}/cm^{-3}\:n-$형이다. 제작 소자는 접합 장벽 쇼트키 다이오드이며, 항복전압을 개선시키기 위해 고농도 의 보론 보호테의 불순물 분포를 사각모양 설계하였으며, 보호태의 폭과 간격을 변화하였다 . 정류성 접촉 금속은 $Ni(3,000\:{\AA})/Au(2,000\:{\AA})$ 사용하였다 . 결과로써, 소자의 특성은 온-상태 전압이 1.26 V, 온-상태 저항은 m$45m{\Omega}/cm^{3}$으로 낮은 특성과역방향 항복전압은 1,180 V의 최대값이며, 이 항복전압의 역방향 누설전류밀도는 $2.26*10^{-5}A/CM^{3}$의 값이며, 전기적 파라미터의 특성 결과가 개선되었다. We have used the silicon-carbide(4H-SiC) instead of conventional silicon materials to develope of the planar junction barrier schottky rectifier for ultra high breakdown voltage(1,200 V grade). The substrate size is 2 inch wafer, Its concentration is $3*10^{18}/cm^{3}$ of $n^{+}-$type, thickness of epitaxial layer $12{\mu}m$ conentration is $5*10^{15}cm^{-3}$ of n-type. The fabticated devices are junction barrier schottky rectifier, The guard ring for improvement of breakdown voltage is designed by the box-like impurity of boron, the width and space of guard ring was designed by variation. The contact metals to rectify were used by the $Ni(3,000\:{\AA})/Au(2,000\:{\AA})$. As a results, the on-state voltage is 1.26 V, on-state resistance is $45m{\Omega}/cm^{3}$, maximum value of improved reverse breakdown voltage is 1180V, reverse leakage current density is $2.26*10^{-5}A/CM^{3}$. We had improved the measureme nt results of the electrical parameters.
Seo, Sang Won,Lee, Jong-Min,Im, Kiho,Park, Jun-Sung,Kim, Sook-Hui,Kim, Sung Tae,Ahn, Joong Hyun,Kim, Min-Jeong,Kim, Geon Ha,Kim, Jong Hun,Roh, Jee Hoon,Cheong, Hae-Kwan,Na, Duk L. Lippincott WilliamsWilkins, Inc. 2012 Alzheimer disease and associated disorders Vol.26 No.2
Cardiovascular risk factors are associated with cognitive impairments. However, the effects of cardiovascular risk factors on the topography of cortical thinning have not yet been studied in patients with mild cognitive impairment (MCI) or dementia. Thus, we aimed to evaluate the topography of cortical thinning related to cardiovascular risk factors and the relationships among cardiovascular risk factors, white matter hyperintensities (WMH), and cortical atrophy. Participants included 226 patients with Alzheimer disease or subcortical vascular dementia and 135 patients with amnestic MCI or subcortical vascular MCI. We automatically measured the volume of WMH and cortical thickness. Hypertension was associated with cortical thinning in the frontal and perisylvian regions, and cortical thinning related to diabetes mellitus (DM) occurred in the frontal region. In path analyses, hypertension accounted for 0.04 of the frontal thinning with the mediation of WMH and 0.16 without the mediation of WMH. In case of DM, it accounted for 0.02 of the frontal thinning with the mediation of WMH and 0.13 without the mediation of WMH. Hypertension and DM predominantly affected frontal thinning both with and without the mediation of WMH, where the effects without the mediation of WMH were greater than those with the mediation of WMH.