• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.164-164
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• 2016

항만 및 해양 구조물은 육상과는 비교할 수 없을 정도로 가혹한 해수 환경에서 사용되며 계속적으로 부식 손상을 받는다. 따라서 강구조물이 장기적으로 안전하게 사용되기 위해서는 적절한 방식은 물론 철저한 유지관리가 필수적이다. 한편, 현재 해양환경 중 항만, 조선, 해양산업 등에 많이 이용되는 강구조물은 이에 대응하기 위하여 일반적으로 도장방식이나 음극방식이 사용되고 있다. 음극방식은 피방식체를 일정전위로 음극 분극하는 원리로써 외부전원을 인가하거나 비전위의 금속을 희생양극으로 연결하여 방식하는 방법이다. 이와같이 해수 중 음극방식을 실시할 경우 해수 중 용존하는 많은 이온들 중에서 특히 $Ca^{2+}$ 이나 $Mg^{2+}$ 이온이 탄산칼슘, 수산화마그네슘을 주성분으로하는 화합물로 형성된다. 이렇게 생성된 전착막은 산소 확산을 방지하는 물리적 장벽을 형성하고 부식율을 감소시키는 것으로 보고되고 있다. 그러나 전착막은 소지 금속과의 결합력이 불균일 함은 물론 막을 형성하는데 있어서 장시간이 소요된다는 단점이 있다. 따라서 본 연구에서는 해수 중 음극방식 응용 원리에 의해 전착막을 형성하고, 석출속도, 밀착성 및 내식특성을 향상시키기 위해 해수 중 기체를 용해시켜 제작한 막의 특성을 분석-평가하였다. 본 연구에 사용된 기판(substrate)은 일반구조용 강(SS400)을 사용하였으며, 면적은 $70mm{\times}30mm$, 두께는 1 mm로 제작하여 실험을 진행하였다. 외부전원은 정류기(Rectifier, xantrex, XDL 35-5T)를 사용하여 3 및 $5A/m^2$ 의 조건으로 인가하였고, 양극은 Carbon Rod를 사용하였다. 이때 해수에 주입한 이산화탄소의 양은 0.5 NL/min 였다. 각 조건별로 제작된 전착막에 대해 외관관찰, 석출량, 모폴로지, 조성원소 및 결정구조 분석을 실시하였고, 밀착성 및 내식특성을 평가하기 위해 테이핑 테스트(Taping Test, JIS K 5600-5-6)와 3.5 % NaCl 용액에서 전기화학적 양극 분극 시험을 진행하였다. 시간에 따른 전착막의 외관관찰 결과 전류밀도의 증가와 함께 상대적으로 많은 피막이 형성되었고, 용해시킨 기체에 의해 더 치밀하고 두터운 피막이 형성됨을 확인할 수 있었다. 성분 및 결정구조 분석 결과 $Mg(OH)_2$ 성분의 Brucite 및 $CaCO_3$ 성분의 Calcite 구조 및 Aragonite 구조를 확인하였으며, 용해시킨 기체의 영향으로 $CaCO_3$ 성분의 Aragonite 구조가 상대적으로 많이 검출되었다. 이는 해수 중 용해된 이산화탄소의 영향으로 인해 풍부한 ${CO_3}^{2-}$ 이온이 형성되고 용액 pH를 낮게 유지시켜 Ca 화합물 형성이 용이한 환경이 조성되는 것으로 판단된다. 밀착성 및 내식성 평가를 실시한 결과 해수중 용해시킨 기체에 의해 제작한 시편의 경우 견고하고 화학적 친화력이 높은 Aragonite 결정이 표면을 치밀하게 덮어 전해질로부터 산소와 물의 침입을 차단하는 역할을 하여 기체를 용해시키지 않은 $3A/m^2$ 및 $5A/m^2$ 보다 비교적 우수한 밀착성 및 내식 특성을 보이는 것으로 사료된다.

• Korean Journal of Plant Taxonomy
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• v.33 no.4
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• pp.455-472
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• 2003

The period from 1946 until his retirement from Department of Forest Resources, Seoul National University was a time of research and professional activity on many fronts for Korean Plant Taxonomy. From 1952 to 1984, he travelled south Korea and collected more than 70,000 specimens. Working out of this project, Dr. Lee developed the SNUA herbarium (Herbarium of The Arboretum of Seoul National University) as the best University herbarium in Korea for the modem floristic work. Dr. Lee's first interest rests on his contributions to our understanding of the twig identification in early 1950. Asian deciduous oak taxa have attracted particular focus to him late 1950 and early 1960. Accordingly Dr. Lee has been one of the specialists on systematic study of Asian oak which is a basis of identification in eastern Asia now. Dr. Lee's contributions concerning rare and endangered plants in Korea provide a tremendous information after a Japanese taxonomist, T. Nakai did in early 1920 to late 1930 in Korea. During his fourteen year career from 1970 to 1984, Dr. Lee spent time to investigate flora of many local and National Park sites. Much of his effort was directed to the voucher specimens for which he worked for the Illustrated Flora of Korea and also served as a field collector. These collections at SNUA enabled us to extend our educational outreach from the local to the national flora research. Although Dr. Lee has been and continues to be the soul of SNUA, collection records about his purpose and aim for each trip are not well documented except date and field studied sites. This lesson enables us to tackle the same issue of balancing quantity and quality with well documented specimens now.

• Korean Journal of Childcare and Education
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• v.1 no.1
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• pp.103-124
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• 2005

This study aims to investigate and analyze how toddlers' characteristics and child care center's environments including facilities and care-givers' characteristics affect toddlers' behavior in child care center using observational methods. Total 40 toddlers in same numbers of boys and girls participated in this study. Average age of tollers were the 31.7 months ranging from 27 months to 35 months. The toddlers were observed with the observation schedule modified from observation categories of Holloway and Reichhart-Erickson(1988). Data were analysed by Pearson's correlation, t-test, one away ANOVA, Duncan Test and stepwise regression using the SPSSWIN Version. The results of the study were as follow: First, the toddlers' behaviors were related to all the toddlers' characteristics. Second, the toddlers' behaviors were related to all the characteristics of the child care facilities such as the types of facilities, the class size and the caregiver-toddler ratio. Third, the toddler' behaviors were related to caregivers' variables such as the total care experience in centers, the experience with toddler care, the martial status, the certificate types except the child rearing experience and the educational level. Fourth, the toddlers' characteristics were more significantly related to the behavior of them than those of child care centers' environment.

• Korean journal of applied entomology
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• v.30 no.1
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• pp.29-36
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• 1991

Studies were carried out to investigate structural characteristics of the larval and adult light organs of Luciola lateralis Mot. and to observe the relation between the light organ and nerve. The larval light organs, (LLO)existed at a paired dorsal lateral positions of the 8th abdominal segment. The organ was spherical or sub-spherical in shape. There were many vacuoles around the LLO. As larva grew, the number of vacuoles increased. LLO had the muscles in its interior part and their role seemed to fix the LLO position in space. Also, there were the tracheae and tracheoles in LLO. The Adult light organs (ALO) were at the ventral portions of the 5th and 6th abdominal segments in the male, but only on the 5th abdominal segment in the female. ALO had two functional layers, i.e., photocyte and dorsal layer. Tracheal end organs existed in both layers but their arrangements were irregular. Rod-shaped photocytes and spherical photocytes were observed in the ALO of male and female, but the rod-shaped types were rarely found in the female. In the ALO of the 5th abdominal segment, two paired peripheral nerves were originated from the anterior part of the last abdominal compound ganglion. A pair of peripheral nerves were originated from the posterior part of the compound ganglion to innervate the 6th abdominal segment ALO. And LLO was innervated by a paired peripheral nerves from the last abdominal ganglion.

• 대한공업교육학회지
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• v.43 no.2
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• pp.43-60
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• 2018

The purposes of this study are to compare practical ability of vocational education high school, investigate effectiveness of recruitment practical examination, and provide basic data that can be helpful to recruit teaching staffs of occupational training institution in the middle stage and strengthen practical guidance capability of teacher through the analysis by variables of teacher's background. To achieve them, concrete capability areas related to practical ability were conceived and differences of new teacher's abilities were compared between area that fulfilled recruitment practical examination and areas that didn't fulfill. The conclusions of this study are as follows. First, practical abilities among specialized subject teachers of vocational education high school were compared by existence of vocational education high school teacher recruitment practical examination. As a result, the average of practical ability of the group who was fulfilled by recruitment practical examination was somewhat high in all of 5 sub-areas for practical ability, but wasn't significant statistically. Second, the differences of practical ability by background variable among specialized subject teacher of vocational education high school were compared. As a result, the group who possesses national technology licence, existence of short-term teaching career, teaching course completion form of open teacher training showed higher average and it showed significant differences statistically.

• Journal of dental hygiene science
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• v.17 no.2
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• pp.99-107
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• 2017

The purpose of this study was to identify knowledge awareness, and performance of dentist and dental staff regarding protection of patient's personal information. In addition, this research was conducted to highlight the importance of protection of patient's personal information and provide a guideline for establishing measures in this regard. A survey was conducted on 506 dentists or dental staff working in Seoul, Gyeonggi and Chungcheong provinces. The data was analyzed using t-test, one-way ANOVA, $x^2$, Pearson's correlation coefficient, and Scheffe test, using the PASW Statistics ver. 18.0 program. We found that the participants' knowledge and perception of the protection of patient's personal information were relatively low compared to those of other professionals. Such knowledge and perception were especially and significantly low in dental hygienists. In addition, a high level of knowledge and awareness showed a positive correlation with the extent of performance. Therefore, it is important that dentists and dental staff are aware of issues regarding the protection of patients' personal information. For this purpose, educational and training programs on such issues appear essential.

• Korean Journal of Environment and Ecology
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• v.31 no.1
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• pp.24-29
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• 2017

This study was conducted to identify nesting habits and breeding biology of barn swallow in Gwangju, Korea, for the breeding season 2012 to 2014. All nests were attached to vertical walls and roofs of buildings and situated at mean height $2.9{\pm}0.3m$ above ground with nest diameter $18.2{\pm}3.2cm$, nest depth $9.8{\pm}3.1cm$, nest cup diameter $11.2{\pm}1.5cm$ and nest cup depth $3.27{\pm}0.80cm$. Nests were attached to cemented walls (44.9%), wooden materials (23.1%), bricks (21.8%) and lighting (6.4%). The average clutch size was 4.5 and ranged 2~5. Mean egg length was $18.23{\pm}0.73mm$, breadth $13.11{\pm}0.25mm$, volume $1.60{\pm}0.11cm^3$, shape index $1.39{\pm}0.05$ and weight $1.69{\pm}0.15g$. Hatching and fledgling success rate were 89.1% and 84.5%. Main causes for reproductive failures were unhatched eggs, predation, nest destruction and desertion. These results are expected to be widely used as data for habitat preservation and species management of barn swallows.

• Journal of Sasang Constitutional Medicine
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• v.11 no.2
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• pp.341-359
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• 1999

In the medical science of 'Sa-sang', a constitutional examination(diagnosis) and a medical treatment are important, however a dietary cure is considered as very important at the medical prevention and treatment. But there has been a confusion due to the different view concerning the constitutional foods in between scholars. There it is necessary for us to bring up the theoretical basis of the 'Sa-sang' constitutional - dietary cure by menas of the bibliographical study in relation to a historic, characteristics, efficiency of the major foods.

• Journal of The Korean Association of Information Education
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• v.22 no.1
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• pp.71-80
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• 2018

The purpose of this study is to analyze objectively the current state of preparation of SW education in Korea based on the survey of educational technology of elementary and secondary school which is investigated periodically every year. For this purpose, we extracted indicators related to SW education from educational technology level indicators such as human, material, and utilization and analyzed the change in the level of domestic educational technology level from 2014 to 2016. The main results of this study are as follows. Firstly, the ratio of teachers who have informatics teacher certificates among middle school informatics teacher is continuously decreasing from 2014(71%) to 2016(54%), and the number of information and the number of informatics teachers moving from informatics subject to other subjects is steadily increasing. On the other hand, there is a paradoxical situation in which the total number of teachers in informatics subject is continuously increasing for three years. Secondly, the total amount of ICT related budgets for elementary and secondary schools has been steadily decreasing since 2014. Thirdly, The ratio of informatics(computer) related creative activities in elementary schools dropped to 87.7% in 2015 and 84.6% in 2016. Also, the ratio of informatics subject operating school in middle school is gradually decreasing from 34.8% in 2014, 30.8% in 2015, and 28.2% in 2016. Based on the results of this analysis, this study suggested a method for stable settlement of SW education in elementary and secondary public education field.

• Journal of Digital Convergence
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• v.13 no.5
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• pp.277-288
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• 2015

This study aims to identify determinants affecting on geographic variations in the prevalence of arthritis in Korean women using data mining. Data from Korean Community Health Survey 2012 with 249 small districts were analyzed. Socio-demographic, health behavior and status, and morbidity status measures were analyzed using conventional regression model and convergence analysis method such as decision tree for convergence analysis. Rate of workers in agriculture, forestry, and fishing, salaried workers, persons higher than high school graduates, non-treatment of needing care, non-treatment of care because of economic reason, obesity, heavy drunkers, complaining persons of chewing difficulty, persons with experiencing depression, persons with perceiving stress, and persons with diagnosing hypertension and angina pectoris were variation determinants of prevalence of arthritis in 249 small districts and these districts were classified 10 area groups by decision tree model. Our finding suggest that the approach based characteristics by small area groups rather than national wide or individual level would be effective to reduce in variations of prevalence of arthritis.