• Journal of the Korean Chemical Society
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• v.44 no.6
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• pp.611-624
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• 2000

In this study we analysed 3-12 grade science textbooks, many literatures and internet sites related to diffusion and dissolution concepts. From these data, we discovered that the explanations of diffusion that used in textbooks are not considered the site of collision with mediums, and confused with dissolution, state transition and effusion. In the case of dissolution, almost analysis data were short of the explanations of interaction effect. Most of all, the focus of dissolution explanations was to solve the calculation problems rather than to understand the concept. Every internet site was poor, just as the level of showing textbook contents with computer, so the only effect of using computer was the sense of sight and hearing. Chemistry must be understood nature phenomena with a view point of particle theory, but many textbooks and Internet sites didn't represent it sufficiently. We set up the correct scientific concept and linked micro world of particle theory with macro world of nature phenomena. With a use of computer which have the advantage of representing moving things, we developed the computer-assisted instruction programs related to diffusion and dissolution with the viewpoint of particle movement.

• Korean Journal of Veterinary Service
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• v.33 no.2
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• pp.185-197
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• 2010

This study was conducted to evaluate the alleviative effects of activated charcoal (AC) and Houttuynia cordata (HC) singly or in combination in broiler chickens during aflatoxicosis. Activated charcoal (1% or 0.5%) and H. cordata (1% or 0.5%) were mixed into the diets for the ability to reduced the deleterious effects of 2.4mg total aflatoxin $(AFB_1)kg^{-1}$ diet on growing broiler chickens from 1 to 21 days of age. A total of 160 1-day-old (Hyline Variety Brown) broiler chicks were housed in eight treatment groups [Control, $AFB_1$, AC 1%, HC 1%, $AFB_1$ plus AC 1% plus HC 1%, $AFB_1$ plus AC 1% plus HC 0.5%, $AFB_1$ plus AC 0.5% plus HC 1%, $AFB_1$ plus AC 0.5% plus HC 0.5%] each consisting of 20 chicks. Compared to control, 2.4mg $AFB_1$ alone treatment group significantly decreased body weight gains of chickens. The addition of mixed AC 1% and HC 1% including 6, 7 groups to the 2.4mg $AFB_1$-containing diet moderately reduced the adverse effects of $AFB_1$ on performances of chickens. The chickens consuming 2.4mg $AFB_1$ plus AC 0.5% and HC 0.5%-containing diet showed very slightly reduced the adverse effects on investigated parameters compared to the $AFB_1$ only treated group. Also, the single addition of AC or HC to the $AFB_1$-free diet had no adverse effects in chickens. These results suggest that AC and HC mixed can reduced the aflatoxicosis in broilers and may be contribute to a solution of the aflatoxicosis problem in poultry production.

• Journal of the Korean earth science society
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• v.30 no.6
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• pp.709-720
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• 2009

Field observation and numerical experiments were conducted to understand the impact of water retention pavement on the surface heat budget and on the regional circulation. The numerical model applied in this study is the atmospheric dynamic model Local Circulation Model (LCM) with two dimensional grid system, and a field observation was carried out under the clear sky and calm conditions of the weather on 19 July 2007. In the field observation, the maximum value of surface temperature on pavement covered with water retention material reached the $41.2^{\circ}C$ at 1430 LST and the values was lower for $16.1^{\circ}C$ than that of asphalt without the material. The Case BET03 assumed to be 0.3 for the surface evaporation efficiency was in good agreement with the observation and its sensible and latent heat fluxes were numerically estimated to be 229 and 227 $W/m^2$, respectively. Results of the numerical experiments demonstrated that the water retention pavement tends to induce the increase of latent heat flux associated with the lower surface temperature and mixing height during the daytime. Discontinuity of latent heat caused by the water retention pavement also tends to promote the development of mesoscale circulation called as land-land breeze or country breeze.

• The Journal of Korean Academy of Prosthodontics
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• v.43 no.2
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• pp.204-217
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• 2005

Purpose. The purpose of this study was to analyze stress distribution of all ceramic posterior fixed partial denture using a three dimensional finite element method. Material and method. A three dimensional finite element model was created to demonstrate all-ceramic posterior fixed partial denture and then this computer model measured the stress distribution of the all ceramic bridges which has a ceramic core materials such as Zirconia, IPS Empress. 2. In-Ceram zirconia, Metal-Ceramic. Also the stress distribution was examined according to loading sites when force was applied to sites such as the central area of second premolar the mesial connector of pontic, the central fossa of pontic, the distal connector of pontic, and the central fossa of second molar. Results. 1. In all the materials of the core in this study, von Mises stress indicated that the stress increased as force was applied to loaded sites, just at those points, on the connector, and the margin in the area adjacent to the connectors. 2. The maximum principal stress was much higher in the lower part of the connectors than in any other region. 3. As the load was applied to the different locations, the research showed a consistent increase of stress in the lower connectors. The maximum value of the von Mises stress was two or three times greater when the load was applied directly to the connectors rather than indirectly through another stressed region. 4. In the case of In-Ceram zirconia, the stress in lower connectors was the highest of all the reference points, the stress showed 75% of all the maximum stress. Ziconia showed 72%, Metal Ceramic 67% and IPS Empress 2 50%. 5. In the case of Ziconia, the stress was well dispersed in each reference point that the stress differences were smaller when compared to In-Cream ziconia.

• Journal of Periodontal and Implant Science
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• v.36 no.1
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• pp.167-177
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• 2006

연구배경 임플란트에 관한 전통적인 연구들은 주로 임플란트 매식체와 골조직간의 결합에 중점을 두어왔다. 최근 임플란트의 심미적 관점에 대한 관심이 높아지면서 임플란트 주위 연조직의 재건 및 유지에 대한 연구들이 많이 이루어지고 있다. 이번 연구는 임플란트 주위 연조직이 임플란트 지대주의 모양에 따라 어떻게 반응하는지 알아보고자 한다. 연구방법 및 재료 2 마리의 성견을 대상으로, 먼저 하악의 모든 소구치를 발치하고, 3개월의 치유 기간 후에 각 4분악에 실험에 사용된 3개의 다른 모양의 지대주를 가진 임플란트를 식립하였다: (1) 위로 벌어진 모양의 지대주 (2) 안쪽으로 오목하게 좁아진 지대주 (3) 평행한 모양의 지대주. 식립 순서는 무작위로 하였으며, 3개월 후 실험동물을 희생하고 조직 표본을 얻었다. 조직 표본은 광학 현미경을 통해 관찰하고, 상피, 결합조직, 전체 연조직의 수직적 거리를 측정하여 비교하였다. 연구 결과 이번 연구에서 임플란트 주위의 연조직을 측정한 결과, 접합 상피는 1.21 ${\pm}$ 0.47 mm, 결합조직은 1.16 ${\pm}$ 0.39 mm, 전체 연조직 두께는 2.37 ${\pm}$ 0.47 mm로 이전의 연구들과 비슷한 결과를 보였다. 지대주 주위의 연조직 중 결합조직이 많은 부위에서는 여러 주행 방향의 교원 섬유들이 관찰되었다. 그 중에서 결합조직이 차단막으로써의 역할을 할 수 있도록 하는 원형으로 주행하는 교원 섬유들이 모든 지대주 모양에서 관찰되었다. 특히 오목하게 좁아진 모양을 가진 지대주에서는 오목하게 파인 부분으로 많은 원형으로 주행하는 교원 섬유들이 관찰되었다. 오목한 모양의 지대주는 다른 모양의 지대주에 비해서 측면 방향의 연조직 두께가 두꺼웠다. 특히 위로 벌어진 모양의 지대주에 비해서 두꺼운 연조직을 확보할 수 있었으며, 내부에 많은 결합조직 교원 섬유들을 관찰할 수 있었다. 결론 이번 연구에서 오목한 모양의 지대주가 연조직을 두껍게 유지하고, 많은 원형으로 주행하는 교원 섬유들을 확보할 수 있었다. 이를 통해 오목한 여태의 지대주가 연조직 유지에 더 유리하고, 따라서 심미적인 부위에서 연조직의 퇴축을 예방하는데 더 유리하다고 할 수 있다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.3
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• pp.292-296
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• 2009

Tyrosinase catalyzes melanin synthesis in skin melanocytes. The effects of Paeonia sufficinalis water extract (MDP) on antioxidant and tyrosinase activities have been studied in a cell-free system and mouse melanoma B16 cell. Radical scavenging activity of MDP was tested by DPPH assay and it showed high DPPH radical scavenging activity. The cellular tyrosinase activity was measured in mouse melanoma B16 cell by RT-PCR and enzyme activity. Treatment with MDP for 24 hr resulted in decreased tyrosinase mRNA level. Tyrosinase activity was decreased, compared with control, in cells exposed to MDP. Thus, Paeonia sufficinalis water extracts may be a candidate for cosmetic use.

• Journal of The Korean Association For Science Education
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• v.33 no.2
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• pp.538-551
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• 2013

Korea is reported as one of the highest performing OECD countries in PISA 2009 science achievement, ranking $4^{th}{\sim}7^{th}$ among 65 participating countries. However, the top level 6 percentage came only at 1.1% and ranks $18^{th}$ among paticipating countries. Such dissatisfying results call for attention to seek effective teaching and learning strategies for top level students in Korea. This study aims to investigate the effect of reading motivational and behavioral factors on PISA 2009 science achievement for the population who scored high compared to populations scoring middle and low. For this purpose, PISA 2009 science achievement as well as students questionnaire data were utilized. Variables of reading motivational and behavioral factors were selected and structural equation modeling was employed to examine a hypothetical cause-effect relationship between reading factors and science achievement. It was found that there is a cause-effect relationship between reading factors and science achievement for the whole population. For those in the top 16% of students in PISA 2009 science achievement, reading behaviors on text-memorization have had little or no effects, while reading motivational and other behavioral factors showed a significant influence. In contrast, the middle 68% and low 16% populations have had significant effects for text-memorization on science achievement.

• Child Health Nursing Research
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• v.8 no.4
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• pp.449-457
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• 2002

The main purpose of this study is to examine the concepts appeared on researches and provide the future research directions in field of child health nursing. A descriptive study was conducted. 205 studies were included in an analysis the concepts in terms of the domain of client for a total 321 researches. All were originally published between 1990 and 2000 in Korea. An analysis of concepts for this study was used the metaparadigm framework for nursing proposed by H.S. Kim(2000). The concepts for this study were categorized by essentialistic concepts, problematic concepts, health-care experiential concepts with the following results. 1. Based on the four domains suggested Kim (2000), 205 studies(63.9％) belong to the domain of client ; 109 studies(34％) belong to the practice domain of nursing; 3 studies(0.9％) belong to the client-nurse domain; and 4 studies belong to the domain of environment, respectively. 2. In the domain of client, 117(57.1％) studies used concept of parent. Among them, mother was the prevailing research population(103 studies). 64 studies(31.2％) used child population and the developmental stage of children varied from preterm to puberty but school aged children was the most target population(28 studies). Family as a concept of client was used in 20 studies(9.8％) but most primary care provider was the mother. 3. In terms of research design, non-experimental design(83.5％) is the most and among them survey was 159 studies(77.6％). Qualitative research(23 studies) and experimental research(10 studies) methods were used relatively few. 4. In terms of the categories of concepts, 196 (61.4％) studies included the essentialistic concepts like stress and coping(20.4％), mothering role and child care(7.8％), health (5.6％), breast feeding(4.7％). 31 studies included problematic concepts like power-lessness, safety, obesity, pain, anxiety. And 65 studies included health-care experiential concepts like compliance, growth, hope, environment but relatively few. The findings of this study provide the evidence that research related problematic concept and health-care experiential concept should be conducted actively to improve the practice of child health nursing. Also to deeply understand the phenomena of client in field of child health nursing, interpretive research methods should be conducted actively, too.

• Tuberculosis and Respiratory Diseases
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• v.56 no.4
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• pp.420-425
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• 2004

Fistula between coronary artery and pulmonary artery is a type of coronary artery anomalies. It can cause atypical chest pain and fatigue, angina pectoris, endocarditis, finally myocardial steal can result in heart failure and myocardial infarction. But only 0.1-0.2% of coronary angiographic studies reveal the communications between coronary artery and other spaces. (heart chamber, pulmonary artery etc.) It is frequently congenital, but acquired types are increasing because chest and heart manipulations such as opertion of tetralogy of Fallot, endomyocardial biopsy, radiation therapy, or penetrating blunt trauma are increasing. There are reports about repair of fistula using thrombogenic tips, coil embolization and surgical intervention. We report a connection between coronary artery and pulmonary artery in 79 years old female. She was 30 pack-years smoker and suffered from dyspnea several years with chronic obstructive pulmonary disease. She presented with atypical chest pain and palpitation after admission. Electrocardiography showed ST-T wave abnormality. Emergency coronary angiography and chest CT scan revealed coronary-pulmonary artery fistula. Transcatheter embolization was performed and she was relieved from discomforts.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.89-90
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• 2011

The purposes of this study were to analyze the effects of a marine leisure exhibition event(MLEE)'s appraisal attributes on visitors' satisfaction and repurchase behavior and thus provide fundamental information that facilitates developing effective marketing and operational strategies for a MLEE. In order to accomplish such purposes, this study employed a survey with a total of 300 visitors to a MLEE hosted by G Province. Questionnaires were developed on the basis of related studies and modified to reflect the study context. Then, such questionnaires were verified to be valid and reliable through content validity, exploratory factor analysis and internal consistency analysis. Valid 286 questionnaires were analyzed with correlation analysis and multiple regression analysis on significance level of .05. Following findings were derived from current study. First of all, the appraisal attributes of a MLEE had a significant effect on visitors' satisfaction and among them only the factor of event program had a unique relation with the levels of satisfaction. In addition, the appraisal attributes of the MLEE also had a significant effect on visitors' repurchase behavior and among them event program, transportation and employee factors had unique relations with the performance variable in order. In conclusion, all the research hypotheses that had been set up through previous studies were confirmed in this study.