KIST와 FZ-Julich SOFC간의 출력성능 비교

정화영,이상철,김혜령,이해원,이종호,Jung, Hwa-Young,Lee, Sang-Cheol,Tietz, Frank,Kim, Hae-Ryoung,Lee, Hae-Weon,Lee, Jong-Ho 한국세라믹학회 2007 한국세라믹학회지 Vol.44 No.12

We evaluate and compare the power generating characteristics of the anode supported SOFCs which have been fabricated from KIST and FZ-Julich in Germany. The performance and electrochemical property of each unit cell was characterized at the temperature range of $650-850^{\circ}C$ under same operating conditions and its microstructural property was thoroughly investigated via SEM after the performance test. According to the investigation, KIST- and FZJ SOFC showed different power generating characteristics in their temperature dependances due to their different design of electrode microstructure, especially the cathode microstructure. FZJ SOFC showed better performance at high temperature while showed lower performance at lower temperature. From the investigation about the correlation between microstructure and electrochemical property, we found that the superior performance of FZJ SOFC at high temperature was mainly due to its lower cathodic polarization resistance whereas better performance of KIST SOFC at lower temperature was mostly attributed to the lower ohmic resistance.

음극지지형 단전지를 사용한 소형 SOFC 스택의 제조 및 출력특성

정화영,김우식,최선희,김주선,이해원,고행진,이기춘,이종호,Jung, Hwa-Young,Kim, Woo-Sik,Choi, Sun-Hee,Kim, Joosun,Lee, Hae-Weon,Ko, Haengjin,Lee, Ki-Chun,Lee, Jong-Ho 한국세라믹학회 2004 한국세라믹학회지 Vol.41 No.10

In this research, $5\times5cm^2$ unit cells were fabricated via liquid condensation process and uniaxial pressing followed by the screen printing of electrolyte and cathode layer. The SOFC stack was assembled with unit cells, gasket-type sealant and metal interconnect. The stack was designed to have a single column with internal-manifold and cross-flow type gas-channels. The SOFC stack produced 15 W, which is $50\%$ of the maximum power being expected from the maximum power density of the unit cell. Controlling factors for the proper operation of the SOFC stack and other designing factors of stack manifold and gas channels were discussed. 액상응결 공정법과 일축가압성형법으로 제조된 기판위에 전해질과 양극층을 스크린 인쇄법으로 구성한 후 열처리함으로써 최종크기가 $5\times5cm^2$인 SOFC 단전지를 제조하였다. 본 연구에서는 이들 단전지와 인코넬 합금으로 제조된 접속자 그리고 가스켓형의 밀봉재를 이용하여 스택을 구성하였다. 본 연구에 사용된 스택은 연료가스와 산화가스가 교차되는 형태의 가스채널을 가지며 가스매니폴드가 내부에 구성되어 있는 형태로 설계되었다. 제작된 3단 스택의 성능을 평가해 본격과 15W 정도의 최고출력을 나타내었는데 이는 단전지 출력성능으로부터 예측된 최고출력치의 $50\%$ 정도에 해당되는 출력이었다. 본 연구에서는 이러한 스택성능에 영향을 주는 조정인자들과 스택디자인 인자들에 대한 분석을 수행하였다.

성별에 따른 유아의 정서능력과 어머니의 정서표현성과의 관계

정화영(Jung Hwa-Young),성소영(Sung So-Young) 계명대학교 사회과학연구소 2009 한국사회과학연구 Vol.28 No.2

The purpose of this study is to examine gender differences of young child's emotional competence and the relationship between emotional competence and the variation of mother's emotional expression across child's gender. The subjects of this study are selected from twelve Kindergartens and Child Care Centers located in Taegu and Gu-Mi. They are 326 children who are aged 5 to 6 and their mother. The children's Kindergarten teachers rated children's emotional competence as using measure of Woo's(2002) Emotional Competence Index for Children. The measurement of emotional expression of their mothers are measured by using the SEFQ developed by Halderstadt and his colleagues(1995) and adjusted by Seo(2006). Statistical analyses by using SPSS Win 14.0K are descriptive statistics including mean and standard deviation, t-test, and Pearson's correlation. Especially, Pearson's correlation is used to examine the relations between child's emotional competence and mother's emotional expression. The findings of this study are as follows: First, statistically significant gender differences in young child's emotional competence were found between boys and girls. Girls' emotional competence in, emotional expression, emotional recognition of others, emotional regulation, empathy, and emotional language was significantly higher than those of boys. Second, there were not found to be significant differences in mother's emotional expression according to child's gender. Third, testing the relationships between young children's emotional competence and mother's emotional expression showed that girls' emotional competence was somewhat related to mother's positive and negative emotional expression, while boys' emotional competence does not have an association with mothers' emotional expression. Therefore, these results showed that not only young children's gender but also mother's emotional expression was an important variable in young children's strategies of emotion competence.

압력센서를 이용한 실시간 앉은 자세 모니터링 시스템

정화영(Hwa-Young Jung),지준근(Jun-Keun Ji),민세동(Se Dong Min) 대한전기학회 2015 전기학회논문지 Vol.64 No.6

A Sitting posture is a very important issue for moderns who is mostly sedentary. Also, a wrong sitting posture causes back-pain and spinal disease. Many researchers have been proposed numerous approaches that classifying and monitoring for a sitting posture. In this paper, we proposed a real-time sitting posture monitoring system that was developed to measure pressure distribution in the human body. The proposed system consists of a pressure sensing module (six pressure sensors), data acquisition and processing module, a communication module and a display module for an individual sitting posture monitoring. The developed monitoring system can classify into five sitting postures, such as a correct sitting, sitting on forward inclination, leaning back sitting, sitting with a right leg crossed and a left leg crossed. In addition, when a user deviates from the correct posture, an alarm function is activated. We selected two kinds of chairs, one is rigid material and fixed form, the other one is a soft material and can adjust the height of a chair. In the experiments, we observed appearance changes for subjects in consequence of a comparison between before the correction of posture and after the correction of posture when using the proposed system. The data from twenty four subjects has been classified with a proposed classifier, achieving an average accuracy of 83.85%, 94.56% when the rigid chair and the soft chair, respectively.

충격손상 복합재료의 피로수명 확률분포 특성

정화영(Hwa-Young Jung),김태성(Tae-Sung Kim),권용규(Yong-Kyu Kwon),한우섭(Woo-Sup Han),강기원(Ki-Weon Kang) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11

This paper presents the probabilistic analysis for fatigue life of Glass/Epoxy laminates with impact-induced damage. For this, a series of impact tests were performed using instrumented impact testing machine. Then, tensile and fatigue tests carried out so as to generate post-impact residual strength and fatigue life. Two Parameter Weibull distribution was used to fit the residual strength and fatigue life data of composite laminates. The variance of residual strength decreased with increasing of impact energy. The fatigue life of impacted laminates was greatly reduced by impact energy and this trend depended on applied stress amplitude. Also, the variation of fatigue life was gradually decreased with the applied stress amplitude.

근전도와 가속도계를 이용한 다목적 시스템의 기초연구

정화영(Hwa-Young Jung),나예지(Ye-Ji Na),왕창원(Chang-Won Wang),민세동(Se-Dong Min) 대한전기학회 2014 대한전기학회 학술대회 논문집 Vol.2014 No.7

무선 ATM 시스템에서 영상 정보 전송시스템의 구현

정화영(Hwa Young Jung),이성식(Lee Seong Sik) 한국통신학회 1999 한국통신학회 학술대회논문집 Vol.1999 No.11

한배 산란수와 알 크기 조절을 통한 붉은머리오목눈이(Paradoxornis webbianus)의 번식투자

정화영(Hwa-Young Jung),박정은(Jung-Eun Park),유정칠(Jeong-Chil Yoo) 한국조류학회II 2012 한국조류학회지 Vol.19 No.4

본 연구는 붉은머리오목눈이(Paradoxornis webbianus)의 한배 산란수와 알의 크기 조절을 통한 번식투자를 알아보기 위하여 2011년 12월부터 2012년 1월, 그리고 2012년 4월부터 8월에 걸쳐 경기도 양평군 양수리에서 수행되었다. 알 크기 측정 결과 장경은 평균 16.13±0.455㎜, 단경 12.75±0.300㎜, 부피 1.34±0.08㎤으로 나타났으며 한배 산란수는 4개인 둥지 8개, 5개인 둥지 29개, 6개인 둥지가 26개였다. 둥지 간 알 크기의 변이는 전체 붉은머리오목눈이의 알 크기 변이 중 65.85%, 둥지 내 알 크기의 변이는 34.15%로, 둥지 간 알 크기의 변이가 둥지 내에서 보다 컸다. 산란일에 따른 번식 둥지의 수는 2012년 5월 30일을 기준으로 그 전에 둥지가 많이 발견되는 번식기 전반부가 있었고 그 후에는 둥지가 적게 발견되다가 다시 둥지의 수가 많아지는 번식기 후반부가 있었다. 산란일 중 번식기 전반부, 후반부 내에서는 각각 알의 크기가 산란일에 따라 유의하게 증가했으며 산란일 전체에서도 증가했다. 반면, 한배 산란수는 산란일이 후반으로 갈수록 감소하였으며 이는 산란시기의 먹이량 감소 때문인 것으로 추정된다. 둥지 내에서의 알의 크기는 산란순서가 후반으로 갈 수록 유의하게 증가하였다. 새끼의 몸무게는 부화 직후에는 알의 부피에 따라 유의하게 증가하였으나 점차 이소 할 때가 될수록 차이가 없었다. 즉, 작은 알에서 태어난 새끼가 부화 직후에는 큰 알에서 태어난 새끼보다 몸무게가 적지만, 이소 직전에는 차이가 없음을 보여주었다. This study was conducted to investigate parental investment in relation to the clutch size and egg size of the Vinous-throated Parrotbill in Yangseo-myeon, Yangpeyong-gun, Gyeonggi-do from December 2011 to January 2012 and from April to August 2012. Mean egg length, width, and volume was 16.13±0.455㎜, 12.75±0.300㎜, 1.34±0.08㎤, respectively. Number of nests with clutch size of four was 8, five was 29 and six was 26. The egg size variation among clutches can account for 65.85% and within clutches for 34.15%, showing higher variation among clutches than within clutches. Number of breeding nests consisted of two breeding periods with laying date. First half of breeding season appeared before 30th May, 2012 and second half of breeding season followed after that day. In both first and second half of breeding season, average nest egg size significantly increased with laying date and also increased with the entire laying date. However, clutch size decreased with laying date, suggesting the clutch size depended on food abundance. Also, egg size increased with laying order within clutch. Average body weight of 2-day-old nestlings only increased with egg volume significantly, although the statistical value of significance decreased as chicks grew. It means that although average body weight of nestlings hatched from smaller eggs was lighter than those from larger eggs, the difference diminished as chicks were raised until they leave their nests.

압력센서를 이용한 실시간 자세 모니터링 시스템

정화영(Hwa young Jung),왕창원(Wang ChangWon),민세동(Se DongMin) 대한전기학회 2014 대한전기학회 학술대회 논문집 Vol.2014 No.2

환경변화에 따른 웅천천의 어류상과 어류 군집 특성

정화영 ( Hwa Young Jung ),김경환 ( Kyeong Hwan Kim ),송미영 ( Mi Young Song ),이완옥 ( Wan Ok Lee ) 한국환경생태학회 2014 한국환경생태학회지 Vol.28 No.3

We studied fish fauna at 10 study sites in Ungcheon stream for 4 times from April to October, 2011 to investigate the influence of artificial structures such as dam (with fish-way) and weir (without fish-way), and abandoned mine on fish community. A total of 12 families, 36 species of fishes were collected. Dominant species was Zacco platypus (23.4%) and subdominant species was Zacco koreanus (20.5%). Ten species (27.8%) of Korean endemic species and Micropterus salmoides, exotic species, were observed during the study period. Endangered species of Korea such as Pseudopungtungia nigra and Liobagrus obesus, and Korean endemic species, Coreoperca herzi, which are vulnurable for water quality and had been observed in previous study, were not identified in this study. According to the cluster analysis, Ungcheon stream were divided into three groups consisting upstream (St.1, St.2, St.3), midstream (St.4, St.5, St.6, St.7), downstream (St.8, St.9, St.10). Community structure similarity between upper and lower site of Boryeong dam with fish-way (St.6-St.7) was high, whereas that of weir, lack of fish-way (St.7-St.8) showed little similarity indicating that fish-way was required. According to the canonical correlation analysis, high level of conductivity and salinity at upstream was detected and Misgurnus mizolepis, and endemic species of Korea such as Silurus microdorsalis, Coreoleuciscus splendidus and Iksookimia koreensis were observed at this part of the stream. Since Korean endemic species, Squalidus gracilis majimae cohabit with exotic species, M. Salmoides at downstream whose width is wide and water velocity is low, protection was needed for these endemic species.