플렉서블 디스플레이용 저온공정을 갖는 대향 타겟식 스퍼터링 장치를 이용한 ZrO₂ 가스 차단막의 특성

김지환,조도현,손선영,김화민,김종재,Kim, Ji-Hwan,Cho, Do-Hyun,Sohn, Sun-Young,Kim, Hwa-Min,Kim, Jong-Jae 한국전기전자재료학회 2009 전기전자재료학회논문지 Vol.22 No.5

$ZrO_2$ film was deposited by facing target sputtering (FTS) system on polyethylene naphthalate (PEN) substrate as a gas barrier layer for flexible organic light emitting devices (FOLEDs), In order to control the heat of the FTS system caused by the ion bombardment in the cathode compared with the conventional sputtering system, the process characteristics of the FTS apparatus are investigated under various sputtering conditions such as the distance between two targets ($d_{TT}$), the distance between the target and the substrate ($d_{TS}$), and the deposition time. The $ZrO_2$ film by the FTS system can reduce the damage on the films because the ion bombardment with high-energy particles like gamma-electrons, Moreover, the $ZrO_2$ film with optimized condition ($d_{TT}$=140 mm) as a function of the distance from center to edge showed a very uniform thickness below 5 % for a deposition time of 3 hours, which can improve the interface property between the anode and the plastics substrate for flexible displays, It is concluded that the $ZrO_2$ film prepared by the FTS system can be applied as a gas barrier layer or an interlayer between the anode and the plastic substrate with good properties of an uniform thickness and a low deposition-temperature.

Analysis of stress distribution of tooth restored with metal-ceramic crown covering abfraction lesion according to its finish line location under occlusal load

김지환,윤철욱,김태현,김한성,우대곤,이근우,심준성,Kim, Jee-Hwan,Yoon, Chol-Wook,Kim, Taehyeon,Kim, Han-Sung,Woo, Dae-Gon,Lee, Keun-Woo,Shim, June-Sung The Korean Academy of Prosthodonitics 2014 대한치과보철학회지 Vol.52 No.4

목적: 다양한 원인으로 발생된 Abfraction 병소가 있는 치아를 금속도재관으로 수복 할 경우, 변연의 위치에 따라 예후가 다양해질 수 있다. 수복물의 장기적 성공을 검증하기 위해서는 응력분포의 분석이 필요하지만 금속도재관이 abfraction 병소의 적응증인 경우 금속도재관이 응력 분포에 미치는 영향을 밝히는 연구는 아직 없다. 본 연구의 목적은 abfraction 병소가 있는 치아를 수복하는 금속도재관이 바람직한 응력 분포를 나타낼 수 있는 조건을 알아 보고자 함이다. 재료 및 방법: 치아, 주위 조직과 금속 도재관의 외형을 반영한 2차원 유한 요소모델을 제작하고 144 N의 편심 교합력 하에서의 응력분포를 유한요소 분석법으로 분석하였다. 금속 도재관의 변연 위치를 쐐기모양의 결손부의 하연에(Group 0), 그리고 결손부의 하연보다 1 mm 하방(Group 1)과 2mm 하방(Group2)에 위치시켰다. 결과: Group 0에서 von Mises stress는 금속 도재관의 변연과 결손부의 첨부에 집중 되었고 협측 변연의 응력은 설측 부위로 분포되었다. Group 1과 Group 2에서의 응력분포양상은 비슷하게 나타났다. 응력은 결손부의 첨부에 집중되지만 협측과 설측의 응력띠는 서로 분리된 양상으로 나타났다. 결론: 금속도재관의 변연을 Abfraction 병소의 하연에 설정할 경우, 금속도재관은 Abfraction 병소의 첨부에 응력을 집중시킨다. Purpose: When the full veneer crown was treated in the tooth with abfraction lesion due to various causes, the prognosis of it may be compromised according to the location of the finish line, but there is few study about the location of its buccal finish line. The purpose of this study was to investigate the effect of location of the finish line of the full veneer crown on stress distribution of the tooth with abfraction lesion. Materials and methods: The two dimensional finite element model was developed to express tooth, surrounding tissue and full veneer crown. The stress distribution under eccentric 144 N occlusal load was analyzed using finite element analysis. The location of finish line was set just at the lower border of the lesion (Group 0), 1 mm (Group 1) and 2 mm (Group 2) below the lower border of the lesion. Results: In the Group 0, von Mises stress was concentrated at the finish line and the apex of the lesion. Also, the stress at the bucal finish line propagated to the lingual side. In the Group 1 and Group 2, stress distribution was similar each other. Stress was concentrated at the apex of lesion, but the stress at the buccal finish line did not propagate to the lingual side. That implied decrease of the possibility of horizontal crown fracture. Conclusion: Full veneer crown alleviated the stress concentrated at the apex of the abfraction lesion, when the finish line of full veneer crown was set below the lower border of abfraction lesion.

Escherichia coli에서 효소활성을 지닌 Human HtrA3 단백질 제조와 HtrA Serine Protease 1, 2와의 효소활성 비교

김지환,김구영,남민경,김상수,임향숙,Kim, Ji-Hwan,Kim, Goo-Young,Nam, Min-Kyung,Kim, Sang-Soo,Rhim, Hyang-Shuk 한국미생물학회 2009 미생물학회지 Vol.45 No.4

본 연구에서는 Human HtrA3 (HtrA3)의 효소활성을 분자수준에서 연구하기 위해 HtrA간의 상동성과 기존에 알려진 maturation site들을 비교 분석하여 예상 mature HtrA3인 M1-HtrA3와 M2-HtrA3를 발현하는 construct를 제작하였다. pGEX system을 통해 Top10 균주에서 발현, 정제한 M1-HtrA3 단백질은 $10{\mu}g$/L를 정제할 수 있었으며 발현량 대비 1%를 회수할 수 있었다. M2-HtrA3는 M1보다 5배 가량 많은 양을 정제할 수 있었으며 발현량 대비 회수율은 3배 정도 더 높았다. $\beta$-Casein을 이용한 in vitro cleavage test를 통해 M1, M2 form 모두 protease 활성을 갖는 것을 확인하였다. 또한, $\beta$-casein cleavage를 통해 HtrA serein protease들 간의 상대적인 활성을 비교한 결과, HtrA3와 HtrA2는 HtrA1보다 약 2배 더 높은 proteolytic cleavage 활성을 보였다. 본 연구에서 정립한 protease 활성을 지닌 HtrA3의 제작과 정제 조건은 HtrA3의 substrate를 탐색을 용이하게 할 수 있을 것이며, HtrA3 연관된 질환의 발병기전과 세포 신호전달을 이해하는 연구에 활용될 수 있을 것이다. To elucidate HtrA3's functional roles in the HtrA3 mediated cellular processes, it is necessary to investigate its biochemical characteristics. In the present study, we constructed the plasmids encoding putative mature HtrA3 proteins (M1-HtrA3 and M2-HtrA3) based on the putative maturation sites of highly homologous HtrA1 and mouse HtrA3. We used the pGEX bacterial expression system to develop a simple and rapid purification for the recombinant HtrA3 protein. Although yields of the mature HtrA3 proteins were slightly low as 10~50 ${\mu}g$/L, the amounts and purity of M1- and M2-HtrA3 were enough to investigate their proteolytic activities. The putative mature HtrA3 proteins have proteolytic activity which could cleave $\beta$-casein as an exogenous substrate. We compared the proteolytic activity between the HtrA family, HtrA1, HtrA2, and HtrA3. The cleavage activity of HtrA3 and HtrA2 were 2 folds higher than that of HtrA1, respectively. Our study provides a method for generating useful reagents to identify natural substrates of HtrA3 in the further studies.

거시계량투입산출 모형을 이용한 광산품 수입대체의 경제적 효과 추정 연구

김지환,이경한,김윤경,Kim, Ji-Whan,Lee, Kyung-Han,Kim, Yoon Kyung 대한자원환경지질학회 2014 자원환경지질 Vol.47 No.3

본 연구는 산업연관표의 투입산출표와 거시계량경제모형을 연계하여 산업부문에 발생한 충격의 효과가 거시변수에 미치는 효과를 예측할 수 있도록 모형화 하였으며, 모형을 통해 광산품 부문의 수입대체에 따른 경제적 효과를 추정하였다. 구축한 모형의 전반적인 개요는 거시계량경제모형을 구축하고 산업연관표를 통해 도출된 피용자보수를 국민계정상 가처분소득의 대리변수로 이용하여 두 분석틀을 연계하였다. 거시계량경제모형은 한국은행이 작성한 1997년 기준 모형을 근간으로 하여 최근의 한국은행 모형을 통해 수정 및 보완하여 2011년 기준의 연간 거시계량경제모형을 구축하였으며, 산업연관분석과 연계되는 가처분소득과 총취업자수 부분을 수정도입하였다. 산업연관표 부분은 2005년~2011년의 통합대분류 경상표 및 그 계수표를 이용하였다. 구축된 모형을 적용하여 광산품 중간투입 중 1%의 수입대체가 미치는 경제효과를 추정하였는데, 2011년 기준으로 GDP 0.00073% 증가, 경상수지 0.01040% 증가, 실업률 0.00233%p 감소의 효과가 나타났다. 본 연구는 거시변수를 이용하여 지출측면 중심으로 활용되던 거시계량경제모형에 산업연관표를 활용함으로써 산업 수준의 충격과 투입부문을 고려할 수 있도록 하였다는 점에 의의가 있다. In this study, it is estimated how many changes of macroeconomic variables are happened under the proposition of import substitution of mining products 1% using macroeconometric input-output model. For this, used macroeconometric input-output model is composed of 141 behavioral equations representing the macroeconomy structure. In general, macroeconometrics models are constructed mainly on the side of the expenditure then it is not easy to estimate the effects of the shocks occurred from industry level. To mitigate that, this study tries to construct a macroeconometric input-output model. Macroeconometrics model which is useful to estimate the effects of macroeconomic shocks, economic policy and more, in this study, is linked with input-output table through the NDI(national disposable income) derived from compensation of employee. And this paper presents the estimation results of import substitution effects of mining products on Korean economy. As a results, GDP is increased 0.00073%, gross labor employed 0.00029%, current balanace 0.00010% and unemployment rate is mitigated 0.00233%.

진공 웹코터로 제작된 대면적 ITO/PET의 특성 연구

김지환,박동희,김종빈,변동진,최원국,Kim, Ji-Hwan,Park, Dong-Hee,Kim, Jong-Bin,Byun, Dong-Jin,Choi, Won-Kook 한국재료학회 2007 한국재료학회지 Vol.17 No.10

Indium tin oxide, which is used as transparent conducting layer in flexible device, is deposited on PET film by a magnetron sputtering in 300 mm wide roll-to-roll process (vacuum web coating). Sheet resistance, specific resistance and transmittance is differed by sputtering parameters such as working pressures, oxygen partial pressure, and thickness of ITO layer. ITO layer is deposited about 90 nm at roll speed of 0.24 m/min and its sputtering power is 3 kW. From the XRD spectrum deposited ITO layer is verified as amorphous. Under working pressure varied from $3{\times}10^{-4}\;Torr$ to $2{\times}10^{-3}\;Torr$, sheet resistance is lowest at the working pressure of $1{\times}10^{-3}\;Torr$ and its value is from $110\;{\Omega}/{\square}$ to $260\;{\Omega}/{\square}$ at the thickness of 90 nm. Oxygen partial pressure also varies sheet resistance and is optimized at the regime from 0.2% ($1.8{\times}10^{-6}\;Torr$) to 0.6% ($6{\times}10^{-6}\;Torr$). In this oxygen partial pressure sheet resistance is lower than $150\;{\Omega}/{\square}$. As ITO layer thickness increases, sheet resistance decreases down to $21\;{\Omega}/{\square}$ and specific resistance is about $7.5{\times}10.4{\Omega}cm$ in 340 nm thickness ITO layer. Transmittance is measured at the wavelength of 550 nm and is about 90% for 180 nm thickness ITO/PET.

한국산 녹조식물 해캄속(SPIROGYRA)의 수리표현학

김지환,김영환,이인규,Kim, Ji-Hwan,Kim, Yeong-Hwan,Lee, In-Gyu 한국조류학회(藻類) 2003 ALGAE Vol.18 No.4

The morphotaxonomic characters of the genus Spirogyra were investigated to clarify their taxonomic category and the variation range among species on the basis of comparative morphological and numerical analyses by unialgal cultures and field samples collected from various freshwater habitats in Korea. 25 characters selected on morphological feature of the species were examined on 568 individuals for morphological comparisons and numerical analyses. Width, length and their length/width ratio of vegetative cell, shape of septum, chloroplast number, maximum width, width, length and their length/width ratio of female gametangium, length of male gametangium, size and shape of zygospore, and cell wall ornamentation of the spore showed a comparatively high vector in principal component analysis. In cluster analysis, 15 taxa analysed were divided into 8 major groups by the average taxonomic distance 1.0 level. Considering the morphology and numerical analysis, Spirogyra crassoidea could not be recognized as an independent species, therefore it was treated as a variety of S. ellipsospora. S. koreana (nom. invalidum), recognized as a new taxon, is under the investigation for its clear taxonomic category.

사상체질 식이중재연구 현황분석 : Participant, Intervention, Comparison, Outcome (PICO)를 중심으로

김지환,Kim, Ji Hwan 사상체질의학회 2021 사상체질의학회지 Vol.33 No.1

Objectives The purpose of this study was to evaluate intervention studies on Sasang Constitutional diet (SCD) through the checks of Participant, Intervention, Comparison, and Outcome (PICO) Methods Randomized controlled trial (RCT) and non-randomized study for intervention (NRSI) about SCD were searched in 4 Korean core databases and other sources, and then PICO was checked. Results 1. Total 10 studies were conducted with 1 RCT and 9 NRSIs. 2. Participants were people with no specific disease, or patients with essential hypertension, hyperlipidemia, obesity, or stroke with diabetes or hyperlipidemia. Most studies were conducted on groups of various Sasang Constitutional types except Taeyangin. 3. Two studies provided participants with meals and exercise. Three studies, instead of providing meals directly, taught participants how to eat SCD on their own. 4. NRSIs have tested the effectiveness of various outcome measures without the presentation of primary outcome, and then concluded that all outcomes were ineffective or some are effective. 5. There was no mention of adverse events. In most studies, a single doctor of Korean medicine diagnosed Sasang Constitution the QSCC II questionnaire. The intervention period ranged from three weeks to three months, and recent studies have conducted interventions for 12 weeks. Conclusions Intervention studies about SCD which were conducted so far have shown problems on the study design of PICO items. The study design and implementation that carefully consider how to maintain similarity between groups, minimize the risk of bias, set primary outcome measure, and control the diet are required.

사상체질 식이 중재연구 보고에 대한 질 평가

김지환,이주아,Kim, Ji Hwan,Lee, Ju Ah 사상체질의학회 2020 사상체질의학회지 Vol.32 No.4

Objectives The purpose of this study was to evaluate quality of reporting of intervention studies on Sasang Constitutional diet (SCD) based on the Consolidated Standards for Reporting of Trials (CONSORT) and Transparent Reporting of Evaluations with Nonrandomized Designs (TREND) statements. Methods We searched for Randomized controlled trials (RCT) and Non randomized studies for intervention (NRSI) on SCD in 4 databases and other sources, selected them by the inclusion criteria, and then evaluated quality of reporting of them. Results 1. A total of 10 studies (1 RCT and 9 NRSI) from 1999 to 2006 were selected and evaluated. The detailed items of up to 78%, at least 40%, and median value of 59% in the CONSORT and TREND statements were not reported. 2. One RCT was reporting 4 (11%) sufficiently, and 4 (11%) insufficiently among the 37 detailed items in the CONSORT statement while it was not reporting 29 (78%) items. 3. Nine NRSI were reporting 7 (12%) items sufficiently, and 2 (3%) items insufficiently among the 58 detailed items in the TREND statement while they were not reporting 15 (26%) items. Twenty (34%) items in the TREND statement were reported in some papers but not in more than half. Conclusions The quality of reporting of intervention studies on SCD has been assessed to be generally low. Subsequent researchers are recommended to select an appropriate statement for research design, and use it as a checklist from the time of designing the study to the time of reporting.

Ag 코팅 Cu 플레이크의 제조에서 전처리 및 Ag 코팅 공정 변화의 효과

김지환,이종현,Kim, Ji Hwan,Lee, Jong-Hyun 한국재료학회 2014 한국재료학회지 Vol.24 No.11

To elucidate the effects of a pretreatment process on the uniformity of Ag electroless plating on Cu flakes, pretreatment time was mainly considered with a mixed solution of 0.15 M ammonium hydroxide and 0.0375 M ammonium sulphate. Optical inspection of Ag-coated Cu flakes determined that the optimal pretreatment time is 120 s. Repetition of the sequence in which Ag plating was done immediately after the pretreatment of 120 s clearly enhanced the plating uniformity. Scanning electron microscopy revealed that holes were formed irregularly on some Cu flakes during the period from the asdropping of an Ag precursor solution to 5 min. The hole formation was judged to be due to continuous removal of Cu on the local surfaces by the repetitive formation and elimination of $Cu_2O$ or $Cu(OH)_2$ layers. However, the increase of the amount of Ag coating suppressed the hole creation and increasingly enhanced the antioxidant property.

주성분 분석(PCA)에 의한 항공기 왕복 엔진의 구조 건전도 모니터링

김지환,박성은,이형철,Kim, Ji-Hwan,Park, Seong-Eun,Lee, Hyeong-Cheol 항공우주시스템공학회 2012 항공우주시스템공학회지 Vol.6 No.1

This paper presents a structural health monitoring method of aircraft reciprocating engine using Principal Component Analysis (PCA) which analyzes vibration expressed by Averaged Normalized Power Spectral Density (ANPSD). Because ANPSD of the rotating shaft is sensitive to the rotating speed, this paper proposes to use a post-processing method of ANPSD is used to reduce the sensitivity. The PCA extracts compressed information from the post-processed ANPSDs and the information means the difference between current and normal cases of the engine. The experimental results demonstrate the feasibility and effectiveness of the proposed method to detect abnormal cases of the engine.