알루미늄 PEO 코팅의 결정상에 미치는 공정 조건에 대한 연구 I. Unipolar 펄스와 코팅시간

김배연,함재호,이득용,김용남,전민석,김기윤,최지원,김성엽,김광엽,Kim, Bae-Yeon,Ham, Jae-Ho,Lee, Deuk Yong,Kim, Yong-Nam,Jeon, Min-Seok,Kim, Kiyoon,Choi, Ji-Won,Kim, Sung Youp,Kim, Kwang Youp 한국결정성장학회 2014 韓國結晶成長學會誌 Vol.24 No.2

전해질로 $Na_2SiO_3$을 사용하여 A1050 알루미늄 판재를 pulse 폭 $ 2000{\mu}sec$, impulse 420 V, 400 ${\mu}$sec의 unipolar pulse로 플라즈마 전해 산화 코팅(plasma electrolytic oxidation coating)을 하여 산화 피막을 2, 5, 15, 30분에 따라 형성시킨 다음 산화피막을 분석하였다. 표면에 형성된 산화물의 결정상은 ${\alpha}-alumina$와 ${\gamma}-Alumina$로서 시간에 따른 변화는 없었다. 반응 초반에는 ${\gamma}-Alumina$가 많이 생성되었지만 시간이 갈수록 ${\gamma}-Alumina$의 양에는 변화 없이 ${\alpha}-alumina$가 많이 생겨남을 알 수 있었다. 이런 결과는 micro plasma에 의해서 ${\gamma}-Alumina$가 우선 생성되고, 이후 계속되는 micro plasma의 열에 의해서 ${\alpha}-alumina$로의 전이가 일어나기 때문으로 판단된다. Crystallographic phases of Plasma electrolytic oxidized Al alloy, A1050, were investigated. The electrolyte of PEO was $Na_2Si_2O_3$ and KOH. Unipolar pulse, $ 2000{\mu}sec$ with $400{\mu}sec+420V$ impulse, were applied for 2 min, 5 min, 15 min, and 30 min. ${\gamma}-Alumina$, as well as ${\alpha}-alumina$, was main crystal phase. ${\gamma}-Alumina$ was appeared in the beginning, then the amount of ${\alpha}-alumina$ was increased with time, but the amount of ${\gamma}-Alumina$ remained constant without any increasing. So, it is concluded that plasma gas produce ${\gamma}-Alumina$ at the first, and then ${\gamma}-Alumina$ transform ${\alpha}-alumina$ finally. During the transformation, high temperature of micro plasma gives transformation energy.

알루미늄 PEO 코팅의 결정상에 미치는 공정 조건에 대한 연구 II. Bipolar 펄스와 전해액

김배연,함재호,이득용,김용남,전민석,김기윤,최지원,김성엽,김광엽,Kim, Bae-Yeon,Ham, Jae-Ho,Lee, Deuk Yong,Kim, Yong-Nam,Jeon, Min-Seok,Kim, Kiyoon,Choi, Ji-Won,Kim, Sung Youp,Kim, Kwang Youp 한국결정성장학회 2014 한국결정성장학회지 Vol.24 No.2

A1100, A5052, A6061, A6063, A7075 규격의 시판 알루미늄 합금 판재를 $Na_2SiO_3$와 $Na_2P_2O_7$ 전해질에서 pulse폭 $2000{\mu}sec$, + impulse 420 V, $400{\mu}sec$, -impulse $300{\mu}sec$의 bipolar pulse로 플라즈마 전해 산화 코팅(plasma electrolytic oxidation coating)한 산화피막의 결정상을 분석하였다. 표면에 형성된 산화물의 결정상은 ${\alpha}-alumina$, ${\gamma}-alumina$, ${\eta}-alumina$, $Al_{4.95}Si_{1.05}O_{9.52}$, 그리고 $(Al_{0.9}Cr_{0.1})_2O_3$가 관찰되었다. Bipolar pulse에 의해서 전해액의 성분인 Si가 산화피막에 포함되며, 포함된 Si는 결정상을 형성하기도 하지만 유리상을 형성시킨다. 이때 합금의 Mg 성분은 유리상의 양을 증가시킨다. Micro plasma에 의해서 용융된 표면은 유리상이 먼저 형성되고 이후 계속된 micro plasma의 열에 의하여 새로운 결정상으로 전이가 일어나는 과정을 거치며, 이에 따라 기존에 보고된 결정상이외에도 다양한 결정상이 형성될 수 있음을 추측할 수 있다. Crystallographic phases of Plasma electrolytic oxidized Al alloy, A1100, A5052, A6061, A6063, A7075, were investigated. Two types of electrolyte $Na_2Si_2O_3$ and Na2P2O7 were also compared. Bipolar pulse, $2000{\mu}sec$ with $400{\mu}sec+420V$ impulse and $300{\mu}sec$ - impulse were applied for 20 min. ${\alpha}-alumina$, ${\gamma}-alumina$, ${\eta}-alumina$, $Al_{4.95}Si_{1.05}O_{9.52}$, and $(Al_{0.9}Cr_{0.1})_2O_3$ were mainly observed. Si, component of electrolyte, were moved into the PEO layer by bipolar pulse. Glassy phase was also observed at the surface of $Na_2Si_2O_3$ electrolyte treated PEO layer, and increased with the Mg content of Al alloy. It is concluded that at first glassy phase was formed by the micro plasma, and the high temperature of plasma turns glassy phase to several crystalline phases. And we could expect that many other crystalline phase could be formed by PEO process.

OB-43 : E usefulness of gestation-corrected hyperuricemia as a predictor of the development of preeclampsia on subsequent pregnancy

( Min Youp Choi ),( Yoon Ha Kim ),( Jong Woon Kim ),( Eun Ji No ),( So Mi Choi ),( Tae Bok Song ) 대한산부인과학회 2012 대한산부인과학회 학술대회 Vol.99 No.-

The aim of this study was to determine the usefulness of uric acid to predict the preeclampsia on subsequent pregnancy. The retrospective chart review was done. The pregnant women who had previous preeclampia or gestational hypertension and checked serum uric acid were enrolled in this study. Sixty-two women were collected. Hyperuricemia was defined as being one standard deviation above the gestation-specific mean . And we used uric acid z-scores ([serum uric acid value - gestation specific mean] / standard deviation of the population) to account for gestation-specific alterations in uric acid and tested this as a continuous variable. Linear regression analysis was used to assess the relationship between gestation-corrected hyperuricemia and development of preeclampsia on subsequent pregnancy Of 62 women, twenty had the development of recurrent preeclampsia (32.3%). Linear regression analysis showed that the absence or presence of gestation-corrected hyperuricemia was not associated with the development of preeclampsia on subsequent pregnancy (p=0.551, 95% CI 0.155-2.708). And gestation-specific uric acid z-score as a continuous variable did not show any association with the prediction of preeclampsia on subsequent pregnancy (p=0.725, 95% CI 0.704 - 1.277) Gestation-corrected hyperuricemia does not predict the development of preeclampsia on subsequent pregnancy.

Erratum : Author Correction

( So Mi Choi ),( Min Youp Choi ),( Woo Dae Kang ),( Ho Sun Choi ),( Seok Mo Kim ) 대한산부인과학회 2014 Obstetrics & Gynecology Science Vol.57 No.5

GO-78 : Giant serous borderline tumor of the fallopian tube; A case report

( So Mi Choi ),( Min Youp Choi ),( Woo Dae Kang ),( Ho Sun Choi ),( Seok Mo Kim ) 대한산부인과학회 2012 대한산부인과학회 학술대회 Vol.99 No.-

Abstract Serous tumors of low malignant potential of the ovary are fairly common, making up between 4 and 14% of ovarian epithelial tumors. While to our knowledge serous borderline tumor of the fallopian tube (SBTFT) occurs rarely with only nine previously reported cases in literature. We report the case of the serous borderline tumor of the fallopian tumor in a 25-year-old woman and review the literature.

한국의 Amatoxins 중독증

안영민,이동수,이강문,강상범,양진모,박영민,이영석,정규원,선희식,박두호,노현주,강영모,이종명,허정욱,최성곤,김정호,이상인,최승옥,최홍엽,권오선,구창덕,석순자,김양섭 대한간학회 2000 Clinical and Molecular Hepatology(대한간학회지) Vol.6 No.3

한국의 amatoxins 중독증은 강원 영서 지역이 호발지역으로 알려져 왔으며 최초로 보고된 원인버섯은 알광대버섯이었으나 현재까지 재 확인된 바가 없다. 원인버섯이 확인된 예로는 강원 영서지역이나 대전지역의 독우산광대버섯과 함께 1998년 경북 일원에서 발생한 집단 중독사고의 개나리광대버섯과 대전에서 발생한 1예에서 흰알광대버섯을 들 수 있다. 최근까지 amatoxins 중독증에 관해 보고된 국내의 문헌을 살펴보면 한국에서 발생하는 amatoxins중독증은 사망률에서 외국의 20-40% 와 큰 차이가 있는 것 처럼 보이나 사실상 전체적인 발생빈도나 사망률 등을 산출한 예가 없었을 뿐아니라, 높은 사망률의 원인이 무엇인지를 비교하는 것도 불가능하였다. 저자들은 국내에서 발생하는 amatoxins 중독증의 예방과 보다 효율적인 진단 및 치료를 위해 발생빈도나 사망률 및 원인버섯 등의 기초적인 조사와 함께 문헌을 통해 amatoxins 중독증에 대한 지견을 고찰하고자 하였다. 대상과 방법: 1999년 1년간 원인버섯 식별을 위해 의뢰되었던 증례들과 연례적 호발지역의 의료기관에서 병력 및 임상소견으로 amatoxins 중독증으로 진단 또는 추정된 증례들을 조사하였다. 원인버섯의 식별은 발생지역을 방문하여 원인버섯의 확보가 가능했던 소수의 증례에서는 외관과 현미경적 소견으로 원인버섯을 식별하였으며 원인버섯의 확보가 불가능한 증례에서는 특징적인 외관으로 추정되었다. 결과: 54명의 대상환자들 중 43명에서amatoxins 중독증으로 진단되었으며 그중 35명은 중등도 이상의 중독증으로 간주하였다. 중등도 이상의 중독증에서는 7명이 사망하여 20%의 사망률을 나타내었으며 원인버섯은 독우산광대버섯과 개나리광대버섯이 확인되었다. 흰알광대버섯은 확인되지 않았으나 사실상 독우산광대버섯과의 감별은 이루어지지 않았다. 4예에서는 원인버섯이 확인되지 않아 더 연구 되어야 한다. 사망례에서는 비사망군에 비해 혈소판이 유의하게 감소한 소견을 보였다. 전예에서 간이식등의 치료는 시행되지 않았으며 대부분 수액요법을 근간으로한 보존요법을 실시하였다. 결론: 한국의 amatoxins 중독증은 주로 강원 영서지역과 경북 일원에서 호발하고, 원인버섯은 외국과는 달리 독우산광대버섯과 개나리광대버섯이 주된 원인버섯이며, 1997년 까지의 증례보고를 대상으로한 70%의 사망률과는 달리 중등도 이상의 중독증례를 대상으로 하여도 사망률은 20%로 외국에 비해 높지 않다. 그러나 외국과 달리 간이식과 같은 보다 적극적인 치료를 시도한 예가 없는데, 대부분 갑자기 나빠지기 때문에 준비를 못하는 것이 원인이다. 따라서, 사망률을 더 낮추기 위해서는 혈액이나 소변과 같은 체액에서 단시간 내에 amatoxins을 측정할 수 있는 임상 검사법이 개발되어 조기 진단이 가능해져야 하며, 중독 초기에 나쁜 예후가 예측되는 심각한 증례를 선별하여 전문적인 치료를 받을 수 있는 기회를 제공해야 한다. 아울러 amatoxins 중독증에 대한 보다 정확한 통계를 산출하여야 할 것이다. 저자들은 본 연구에 1999년도에 발생한 대부분의 amatoxins 중독증의 증례가 포함되었으나 포함되지 않은 증례들이 다수 있다고 생각한다. 이러한 기초 조사를 철저히 하기 위해서는 전국 각지에서 발생하는 버섯중독 사고를 의뢰 또는 신고 할 수 있는 일원화 된 창구가 필요하리라고 사료된다. $quot;Background/Aims: From the review of Korean literature most fatal mushroom poisonings have been due to amatoxins with high mortality. So far there have never been investigations on the amatoxins poisonings such as annual incidence, mortality, common causal species, and endemic areas. This study was carried out to develop some basic statistics as part of studies for an effective management of amatoxins intoxications. Method: For the year 1999 authors collected cases of mushroom poisonings which had been mainly gathered from hospitals nation-wide. All of the cases with suggestive amatoxins poisonings were screened by symptomatology and laboratory findings. The causal species of mushrooms were identified grossly and microscopically. Results: A total of 54 victims with mushroom poisonings were evaluated. The causal mushroom toxins were diagnosed or strongly suggested as amatoxins in 43 of 54 victims. Eleven of 54 victims did not conform to the category of amatoxins intoxication due to absent or minimal elevation of aminotransferase. Mean age of the victims was 44.3 23.3 (range: 7-78) with male predominance (1.2 : 1). The causal species were confirmed, or strongly suggested, as Amanita virosa in 25 victims, Amanita subjunquillea in 14, and unknown species in 4. Thirty-five out of a total of 43 were regarded as moderate to severe intoxication (AST or ALT $gt; 1,000 IU/L) with 20% mortality. Most fatal victims showed marked thrombocytopenia (40,000 19,000/mm3) compared to non-fatal victims (109,066 42,245/mm3). A total of 88.4% of victims was developed in the Kangwon and Kyungpuk provinces. Both are west of the Taebaek Mountains (38/43). Conclusions: Although the common causal species for amatoxins poisonings in Korea are different from European countries and North America, the mortality is similar to that of those areas. In order to further reduce the mortality, bedside diagnostic methods using biological fluids and more effective herapy for liver failure should be established$quot;.

중합효소연쇄반응법 ( PCR ) 을 이용한 C 형 간염바이러스 RNA 의 검출

전기엽(Ki Youp Jeon),최영숙(Young Suck Choi),박영민(Yong Min Park),김부성(Boo Sung Kim) 대한내과학회 1994 대한내과학회지 Vol.47 No.3

N/A Objectives: Hepatitis C virus (HCV) accounts for the occurrences of hepatocellular carcinoma, post-transfu- sion non-A non-B (NANR) hepatitis, sporadic NANB hepatitis and aggravates alcoholic liver disease. And we tred polymerase chain reaction (PCR) to evaluate hepatitis C viral infection. Methoda: We detected HCV RNA in the sera from patients with various liver diseases by PCR, to evaluate the replication and infectivity of HCU, And we compared HCV RNA positivity with anti-HCV positivity, Results: 1) In the 107 sporadic NANR liver diease patients, sixteen (15.0%) were anti HCV positive. In the 86 sporadic NANB liver disease patients, thirty-three (38,4%) were HCV-RNA positive. 2) In the 52 HBV-associated liver diasease patients, three (5.8%) were anti-HCV positive. In the 40 HBV- associated liver disease patients, three (12,5%) were HCV-RNA positive. 3) In the various liver diseases, positive rate of HCV- RNA by PCR was 2.1-2.6 times higher than that of anti-HCV. 4) In the total 13,488 blood donors for the three months of Red Cross Blood Center in Chonju, fourty-six (0.34%) were anti-HCV positive and sixteen (53%) among the thirty anti-HCV psitive sera were HCV-RNA positive. 5) Positive rate of anti-HCV of the blood donors, acute and chronic sporadic NANB hepatitis in Chonbuck area was much lower than that of Seoul area. But positive rate of HCV RNA by PCR was similar between two areas. Also positive rates of anti-HCV and HCV RNA in the NANB liver cirrhosis and NANB hepatodellular carcinoma were similar between two areas. Conclusion: By our results, it is suggested that the prevalence of C hepatitis may be underestimated by anti-HCV alone and so the detection of HCV-RNA by PCR is necessary for the true evaluation of HCV infection.

모듈 선체형 삼동 폰툰 보트의 구조설계 민감도 평가와 근사 최적화 해석

최보엽 ( Bo-youp Choi ),손창련 ( Chang-ryeon Son ),손준식 ( Joon-sik Son ),박민호 ( Min-ho Park ),송창용 ( Chang-yong Song ) 한국산업융합학회 2023 한국산업융합학회 논문집 Vol.26 No.6

Recently, domestic leisure boats have been actively researching eco-friendly product development to enter the global market. Since the hulls of existing leisure boats are mainly made of fiber reinforced plastic (FRP) or aluminum, design techniques for securing structural safety by applying related materials have been mainly studied. In this study, an initial structural design safety assessment of a trimaran pontoon leisure boat with a modular hull structure and eco-friendly high-density polyethylene (HDPE) material was conducted, and sensitivity evaluation and optimization analysis for lightweight design were performed. The initial structural design safety assessment was carried out by creating a finite element analysis model and applying the loading conditions specified in the ship classification regulation to check whether the specified allowable stresses are satisfied. For the sensitivity evaluation, the influence of stress and weight of each hull structural member was evaluated using the orthogonal array design of experiments method, and an approximate model based on the response surface method was generated using the results of the design of experiments. The optimization analysis set the thickness of the hull structural members as the design variable and considered the optimal design formulation to minimize the weight while satisfying the allowable stress. The algorithm of the optimization analysis applied the Gradient-population Based Optimizer (GBO) to improve the accuracy of the optimal solution convergence while reducing the numerical cost. Through this study, the optimal design of a newly developed eco-friendly trimaran pontoon leisure boat with a weight reduction of 10% was presented.

On the Minimun Epi Layer Length of RESURF Diodes

韓承燁(Seung-Youp Han),羅鐘民(Jong-Min Na),愼鎭哲(Jin-Cheol Shin),崔然益(Yearn-Ik Choi),鄭相九(Sang-Koo Chung) 대한전기학회 1996 전기학회논문지 Vol.45 No.1

AF relay 를 사용하는 협력 통신 시스템을 위한 MRC 기반의 미세 타이밍 동기 알고리즘

신주엽(Joo-youp Shin),민영일(Young-il Min),장준희(Jun-hee Jang),최형진(Hyung-jin Choi) 한국통신학회 2009 한국통신학회 학술대회논문집 Vol.2009 No.11