고온 및 고온고습 환경 내에서 ZnO:Al 투명전극의 열화가 CIGS 박막형 태양전지의 성능 저하에 미치는 영향

김도완,이동원,이희수,김승태,박지홍,김용남,Kim, Do-Wan,Lee, Dong-Won,Lee, Hee-Soo,Kim, Seung-Tae,Park, Chi-Hong,Kim, Yong-Nam 한국세라믹학회 2011 한국세라믹학회지 Vol.48 No.4

The influence of Al-doped ZnO (AZO) thin films degraded under high temperature and damp heat on the performance deterioration of Cu(In,Ga)$Se_2$ (CIGS) solar cells was investigated. CIGS solar cells with AZO/CdS/CIGS/Mo structure were prepared on glass substrate and exposed to high temperature ($85^{\circ}C$) and damp heat ($85^{\circ}C$/85% RH) for 1000 h. As-prepared CIGS solar cells had 64.91% in fill factor (FF) and 12.04% in conversion efficiency. After exposed to high temperature, CIGS solar cell had 59.14% in FF and 9.78% in efficiency, while after exposed to damp heat, it had 54.00% in FF and 8.78% in efficiency. AZO thin films in the deteriorated CIGS solar cells showed increases in resistivity up to 3.1 times and 4.4 times compared to their initial resistivity after 1000 h of high temperature and damp heat exposure, respectively. These results can be explained by the decreases in carrier concentration and mobility due to diffusion or adsorption of oxygen and moisture in AZO thin films. It can be inferred that decreases in FF and conversion efficiency were caused by an increase in series resistance, which resulted from an increase in resistivity of AZO thin films degraded under high temperature and damp heat.

H_∞ Sampled-Data Control of Takagi-Sugeno Fuzzy System

김도완,Kim, Do Wan Institute of Control 2014 제어·로봇·시스템학회 논문지 Vol.20 No.11

This paper addresses on a $H_{\infty}$ sampled-data stabilization of a Takagi-Sugeno (T-S) fuzzy system. The sampled-data stabilization problem is formulated as a discrete-time stabilization one via a direct discrete-time design approach. It is shown that the sampled-data fuzzy control system is asymptotically stable whenever its exactly discretized model is asymptotically stable. Based on an exact discrete-time model, sufficient design conditions are derived in the format of linear matrix inequalities (LMIs). An example is provided to illustrate the effectiveness of the proposed methodology.

Tm₂O₃가 첨가된 MLCC용 BaTiO₃ 유전체의 전기적 특성 및 열화거동

김도완,김진성,후이,이희수,Kim, Do-Wan,Kim, Jin-Seong,Hui, K.N.,Lee, Hee-Soo 한국결정성장학회 2010 한국결정성장학회지 Vol.20 No.6

Tm 도핑에 따른 $BaTiO_3$ ceramics의 전기적 특성과 열화 거동에 미치는 영향에 대하여 core-shell 형성과 가속열화시험에 의한 미세화학변화의 관점에서 연구하였다. $Tm_2O_3$를 첨가하지 않은 $BaTiO_3$와 1 mol%를 첨가한 $BaTiO_3$를 펠렛과 적층 형태의 시편으로 각각 제조하였다. 1 mol% $Tm_2O_3$가 첨가된 유전체 시편의 유전상수는 $Tm_2O_3$를 첨가하지 않은 시편에 비해 약 40% 높게 나타났고 X7R 조건을 만족하였다. 절연저항 또한 1 mol% $Tm_2O_3$가 첨가된 시편은 $5.43{\times}10^{10}{\Omega}$으로 $Tm_2O_3$를 첨가하지 않은 시편의 $1.11{\times}10^{10}{\Omega}$보다 높게 나타났다. 이는 $Tm^{3+}$ 이온이 Ba site와 Ti site에 선택적으로 치환되고 유전체 미세조직 내에 core-shell 구조를 형성하여 전기적 특성을 향상시킨 것으로 설명된다. 각각의 조성에 따라 제조된 적층 시편의 $150^{\circ}C$, 70 V, 24시간 가속열화시험결과에 따르면, 1 mol% $Tm_2O_3$가 첨가된 $BaTiO_3$는 첨가되지 않은 시편에 비해 전극 층으로의 산소확산이 감소됨을 확인하였고, 이는 $Tm^{3+}$ 이온의 Ti site 치환에 의해 발생한 산소공공이 Ni 전극과 반응할 수 있는 과잉 산소를 줄여주기 때문으로 판단된다. The doping effect of thulium on electrical properties and degradation behavior in barium titanate ceramics ($BaTiO_3$) was investigated in terms of generations of core-shell structure and micro-chemical changes through highly accelerated degradation test. The dielectric specimens of pellet type and multi-layered sheets were prepared by using $BaTiO_3$ with undoped and doped with 1 mol% $Tm_2O_3$. The $BaTiO_3$ ceramics doped with 1 mol% $Tm_2O_3$ had 40% higher dielectric constant (${\varepsilon}$ = 2700) than that of the undoped $BaTiO_3$ specimen at curie temperature and met X7R specification. According to the result of highly accelerated degradation test conducted at $150^{\circ}C$, 70 V, and 24 hr, the oxygen diffusion was declined in dielectrics doped with 1 mol% $Tm_2O_3$. The $Tm^{3+}$ ion substituted selectively Ba site and Ti site and contributed to the generation of the core-shell structure. Oxygen vacancies occurred by substitution for Ti site could reduce excess oxygen that reacted to the Ni electrode.

스마트 윈도우 재료 연구개발 동향

김도완,김슬예,윤진환,Kim, Do-Wan,Kim, Seul-Ye,Yun, Jin-Hwan 한국정보디스플레이학회 2018 인포메이션 디스플레이 Vol.19 No.5

사용자 모델 형성 에이전트 BGP-MS의 활용

김도완,Kim, Do-Wan 배재대학교 공학연구소 1997 공학논문집 Vol.2 No.1

본 논문은 사용자 모델 형성 에이전트에 대하여 그의 필요성과 기술적인 범주를 기술하고 있으며, 사용자모델형성 에이전트인 BGP-MS1)가 어떻게 지능형 대화모형 시스템2)에서 사용자 모델형성 필요성을 만족시키는지 기술하고, BGP-MS와 지능형 대화모델 사이에 귀결하는 인터페이스를 서술하고 있다. 또한 지능형 대화모델 기술개발 프로젝트의 양상을 간단히 소개하고, 사용자 모델형성이 에이전트의 관점으로부터 사용자 모델 형성 측면과 형성된 사용자 모델이 응용 측면을 논하고 있다. This paper documents how the user modeling shell BGP-MS is adapted to suit the user-modeling requirements of the Intelligent Dialog Model(IDM) and descriebes the background information about building a user model framework within BGP-MS, i.e. how to configure the shell system with application specific needs.

환경 독성을 억제하는 느릅 당단백질이 마우스의 분뇨 악취저감 및 사료 효율에 미치는 영향

김도완,박문기,이세중,Kim, Do-Wan,Park, Moon-Ki,Lee, Sei-Jung 한국환경과학회 2020 한국환경과학회지 Vol.29 No.3

Ulmus davidiana Nakai (UDN) has been traditionally used as a herbal medicine in Korea. In the present study, we investigated the anti-ecotoxic potential of a 116 kDa glycoprotein isolated from UDN (UDN glycoprot ein) in regulating fecal malodor and feed efficiency in mice. We found that UDN glycoprotein (200 μg/ml) has an inhibitory effect on the cell death induced by an ecotoxicological endocrine disrupting chemical, bisphenol A, in colon epithelial HT-29 cells. UDN glycoprotein did not show significant differences regarding the weight of ecotoxicity-related organs (liver, heart, kidneys, and spleen) and the levels of serum glutamate oxaloacetate transaminase, glutamate pyruvate transaminase, and lactate dehydrogenase in mice for 2 weeks, compared to the control. Additionally, UDN glycoprotein reduced the levels of hydrogen sulfide and ammonia as markers of fecal malodor in mice. Interestingly, UDN glycoprotein can improve the mouse feed efficiency. In conclusion, our data indicate that anti-ecotoxicological UDN glycoprotein has the ability to increase the feed efficiency and reduce the fecal malodor by maintaining the viability of colonic epithelial cells in mice.

전탕시간(煎湯時間)에 따른 생대황(生大黃) 및 주대황(酒大黃)이 어혈병태모형(瘀血病態模型)에 미치는 영향(影響)

김도완,박창국,Kim, Do-Wan,Park, Chang-Gook 대한한방내과학회 1998 大韓韓方內科學會誌 Vol.19 No.1

In order to investigate the effects of Alcohol-Steamed Rhei Rhizoma and Row Rhei Rhizoma on varied extract time in both endotoxin-induced blood stasis model(hereafter Endotoxin Model) and hydrocortisone acetate-induced blood stasis model (hereafter HA Model), Half of rats were treated with endotoxin(0.4mg/kg, single Ⅳ, into caudal vein) for Endotoxin Model. Thereafter, they were orally administrated water extract of Alcohol-Steamed Rhei Rhizoma or Row Rhei Rhizoma, which were boiled during 30, 60, 120 minute, respectively. Finally, the number of platelet, fibrinogen, prothrombin time, hematocrit, the number of RBC and WBC were measured after sacrifice. The remainder rats were treated with hydrocortisone acetate(10mg/kg, daily IM for 7 days into the muscular rump) for HA significantly decreased. Together, they were orally administrated for 7 days water extract of Alcohol-Steamed Rhei Rhizoma or Row Rhei Rhizoma that were boiled above methods Finally, the number of platelet, fibrinogen, prothrombin time, hematocrit, the number of RBC and WBC were measured after sacrifice. The results were summarized as follows : 1. The number of platelet was significantly increased in boiled water extract for 30 min of Row Rhei Rhizoma group as compared with that of control group in Endotoxin Model. 2. Fibrinogen level was significantly increased in all administration groups as compared with that of control group in Endotoxin Model. It was significantly increased in all administration groups except boiled water extract for 30 min of Alcohol-Steamed Rhei Rhizoma group as compared with that of control group in HA Model. 3. Prothrombin time was significantly shortened in boiled water extract for 60 min of Alcohol-Steamed Rhei Rhizoma group and boiled water extract for 120 min of Alcohol-Steamed Rhei Rhizoma group as compared with that of control group in Endotoxin Model It was significantly shortened all administration groups as compared with that of control group in HA Model. 4 Hematocrit was significantly increased in all administered groups except boiled water extract for 60 min of Alcohol-Steamed Rhei Rhizoma group and boiled water extract for 30 min of Row Rhei Rhizoma group as compared with that of control group in Endotoxin Model. It was significantly increased in all administration groups as compared with that of control group in HA Model. 5. The number of RBC was significantly decreased in boiled water extract for 60 min of Alcohol-Steamed Rhei Rhizoma group, boiled water extract for 120 min of Alcohol -Steamed Rhei Rhizoma group and boiled water extract for 30 min of Row Rhei Rhizoma administered group in Endotoxin Model. It was significantly increased boiled water extract for 30 min of Row Rhei Rhizoma group and boiled water extract for 60 min of Row Rhei Rhizoma group in HA Model as compared with data of control group. 6 The number of WBC was significantly decreased in all administered groups except boiled water extract for 30 min of Alcohol-Steamed Rhei Rhizoma group and boiled water extract for 60 min of Alcohol-Steamed Rhei Rhizoma group as compared with that of control group in HA Model.

기술사마당: 엔진 가변 밸브 기구 이해 및 개발동향

김도완,Kim, Do-Wan 한국기술사회 2011 技術士 Vol.44 No.4

To cope with recent high gas prices and global warming phenomenon, the latest gasoline engine technologies are focusing on direction injection, downsizing by turbo charging, variable compression ratio, controlled auto Ignition to enhance fuel efficiency and satisfy emission regulations. The variable valve train technology will be a basement for these innovative technologies in internal combustion engines and is supposed to play a key role to improve low thermal efficiency and pumping loss in gasoline engine caused by low compression ratio and throttled operation respectively.

Galleria mellonella 유충을 이용한 곤충병원성 선충의 배양 조건

김도완(Do Wan Kim),박선호(Sun Ho Park) 한국생물공학회 1998 KSBB Journal Vol.13 No.1

모터를 적용한 전동 와인 오프너

김도완(Do Wan Kim),유선범,임찬혁,현명훈,정명진(Myung Jin Chung) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.6-2