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      • 대학생들의 안전교육 및 안전의식에 관한 연구

        홍기헌 ; 윤석호 김천대학교 2014 김천대학교 논문집 Vol.35 No.-

        The purpose of this study is to figure out current status of safety education until today and safety consciousness of university students. For this study, the 300 university students were taken among freshmen and sophomores in gimcheon university. Furthermore it is try to realize the necessity of additional safety education in universi-ty and the unification of emergency call numbers. The results are as follows: 1. It was showed that the most students prefer unified emergency call number not divided. 2. Marine accident safety education was lowered compared with other life safety ducations such as fire, earthquake, and traffic safety educations. 3. It was showed that many university students wish additional actual safety educa- tion in university as academic subjects. 4. University students consider that Sewol passenger ship accident was caused by eficient of vocation and safety frigidity of crew and company staffs. And in order to revent this kind of accident, crew vocation should be built up, students safety duca-tion should be strengthened and government agency should watch severely the hip remodelling

      • 콩의 개화기전후 공급과 수용부위의 무기영양성분함량 및 흡수량에 대한 질소의 효과

        박재홍,송범헌,이철원,손석용,김홍식,박상일 忠北大學校 農業科學硏究所 2002 農業科學硏究 Vol.19 No.-

        This study was conducted to examine the nitrogen effects on the uptaken amounts and utilization of mineral nutrients between source and sink tissues at major growth stages before and after the flowering stage with different nitrogen levels Hwangkeum cultivar(Glycine max L Mereill) was cultivated under five different mtrogen levels, 0, 2, 4, 6, 8 N kg/10a Comparing contents of total-N with different plant tissues at major growth stages before and after the flowering, total-N contents of leaves was gradually decreased from the flowering to the beginning maturity, while it of pod was continuously increased from the full seed to the beginning maturity Total-N content was higher in the treatment of 4 N Kg/10a that those of others The uptaken amount of N determined with different growth stage was rapidly increased maturity Higher proportion of uptaken N were into the leaves at the full seed stage, and they were transported from the leaves into pod at the beginning maturity stage Comparing major mineral elements of the leaves and the pod with different N leaves, in case of the leaves, the content of Fe, Mn, and Zn was decreased throughout the growth stages, whereas the content of Ca and Mg was decreased from the flowering to the full seed and then it was increased after the full seed stage In case of pod, the content of K, Fe, Mn, Zn, and Na was decreased from the flowering to the beginning maturity, while contest of Mg was increased.

      • 콩의 개화기 전후 공급과 수용부위의 생장반응과 수량에 대한 질소의 효과

        박재홍,송범헌,이철원,손석용,김홍식,박상일 忠北大學校 農業科學硏究所 2002 農業科學硏究 Vol.19 No.-

        This study was conducted to examine the nitrogen effects on the growth responses, the nodulation, and the distribution of dry weight of plant tissues at major growth stages before and after the flowering stage, and to evaluate the yield components and yields with different nitrogen levels. Hwangkeum cultivar(Glycine max L mereill) was cultivated under five different nitrogen levels, 0, 2, 4, 6, 8, N Kg/10a. Stem length and branching number, which were investigated with different N levels at major growth stages, were rapidly increased for 14days for before and after the flowering stage compared to the other growth stages. They were clearly higher with treatment of 2 and 4 N kg/10a than those of other N treatments. Pod number was slightly increased from the flowering to beginning maturity. It was the highest in the treatment of 2 N Kg/10a. Comparing grain number per pod with different N levels, two grains per pod was much higher in all N treatments except for the treatment of 6 N Kg/10a. Dry weight of shoot(including leaf, stem, and pod) was rapidly increased from the flowering stage to the full seed stage and then gradually increased after the full seed stage, whereas the dry weight of root(including the nodule and root) was rapidly increased until to full pod stage and then linearly decreased from the full pod stage until the beginning maturity stage. Comparing dry weight with different N levels, the dry weight of shoot was the highest in the treatment of 4 N Kg/10a, while it of root was the highest in the treatment of 2N Kg/10a. The dry weight of nodule was the highest, 13.1 Kg/10a, at full pod stage. Comparing the dry weight of nodule with different N levels, it was increased to the application amount of 4 N Kg/10a and then clearly decreased with more application amount of N than 4 Kg/10a. The yield components which were mostly affected to the yield were pod number per plant and grain number per plant. They were 57.5 and 106.1, respectively, with treatment of 4 N Kg/10a, which showed the highest yield, about 266 Kg/10a. Comparing yield index with different N levels to the control, the yields with treatment of 2 and 4 Kg/10a were increased to 21% and 34%, respectively.

      • 브라켓 부착시 실런트 레진이 법랑질 탈회에 미치는 영향

        윤영아,이기헌,황현식,홍석진 전남대학교 치의학연구소 2002 구강과학 Vol.14 No.1

        The purpose of this study was to evaluate the effects of a sealant resin on enamel demineralization in orthodontic bracket bonding. The forty eight extracted sound bovine teeth was subdivided into four groups and treated with Phase Ⅱ^(r) on the surface. Group 1 was not treated, Group 2 was acid etched with 37% phosphoric acid for 30 seconds, Group 3 was sealant applied after acid etching and Group 4 was resin paste applied after acid etching and sealant application. Each group was demineralized in artificial caries solution. Demineralized enamel depth was measured using by confocal laser scanning microscopy. The results were as follows. 1. The mean demineralized enamel depth was Group 1 (47.4㎛), Group 2 (61.8㎛), Group 3 (13.9㎛), Group 4 (8.2㎛). 2. The demineralized enamel depth was increased in Group 2 than Group 1 (p<0.05). 3. The demineralized enamel depth was reduced in Group 3 than Group1 and Group 2 with statistically significant differences (p<0.05). 4. Group 4 was very little demineralized. The results of the present study indicate that sealant application is useful for reducting enamel demineralization in orthodontic bracket bonding.

      • 고정식 교정 환자에서 전동치솔 효과에 관한 연구

        박창헌,이기헌,황현식,홍석진 전남대학교 치의학연구소 2002 구강과학 Vol.14 No.4

        Patients with fixed orthodontic appliances frequently have increased levels of plaque accumulation leading to the possibility of gingivitis or enamel decalcification. Although many methods may be helpful in reducing dental plaque formation, optimal mechanical removal of plaque is tile most important factor during orthodontic treatment. The porpose of this study was to evaluate the efficacy of'an electric toothbrush, with a specially designed orthodontic brush head. compared with a manual toothbrush in controlling plaque and gingivitis for patients with fixed orthodontic appliances. Oral hygiene status was measured in thirty four patients, using a plaquc index, a gingival index and a bleeding index. before and four weeks after attachment of fixed orthodontic appliances. Patients were randomly divided into two groups, the electric and the manual toothbrush groups. Oral hygiene instruction was given according to the type of toothbrush used. The Braun Oral-B D9511 with Braun Oral-B Ortho OD 15-1 brush head was used as the electric toothbrush while the Butler G.U. M 124 was given as the manual toothbrush. After 4 weeks and 8 weeks, oral hygiene status was measured again. Through the comparison berween the electric and the manual toothbrush grpups. following results were obtained. 1. All oral hygiene indices showed increasing tendency after 4weeks of fixed orthodontic appliances. 2. All indices presented decreasing tendency four and eight weeks after oral hygiene instruction. 3. In case of gingival index and bleeding index. decreasing tendency did not show a statistically significant difference between the electric and the manual toothbrush groups. 4. The decreasing tendency of plaque index presented statistically significant difference between the two groups. showing that the electric toothbrush was more effective in terms of oral hygiene. These findings suggest that an electric toothbrush is useful to the orthodontic patients with fixed appliances.

      • KCI등재후보

        고정식 교정 환자에서 전동치솔 효과에 관한 연구

        박창헌,황현식,이기헌,홍석진 대한치과교정학회 2004 대한치과교정학회지 Vol.34 No.4

        고정식 교정장치를 부착한 경우 장치주위의 치태 축적 가능성이 증가되고 이로 인해 치은염, 법랑질 탈회 등의 부작용이 초래 될 수 있는 바 치태 제거를 위한 효과적인 치솔질이 필요하다. 본 연구는 교정환자에서 일반적으로 사용되고 있는 치솔에 비하여 전동치솔이 구강위생에 도움이 되는지 알아보기 위하여 시행되었다. 고정식 장치에 의한 교정치료 예정인 환자 34명을 본 연구의 대상으로 하여 고정식 교정장치 부착 전에 치태지수, 치은염지수, 치은출혈지수를 측정하였다. 장치 부착 4주 후에 각 지수를 측정한 다음, 연구대상을 치솔의 종류에 따라 전동치솔군과 수동치솔군으로 임의 구분하여 수동치솔 또는 전동치솔을 사용하도록 구강위생교육을 각각 시행하였다. 이때 전동치솔의 경우 본체는 Braun Oral-B D9511을 브러쉬 헤드는 Braun Oral-B Ortho OD 15-1을 사용하게 하였으며, 수동치솔의 경우는 Butler G.U.M 124를 사용하게 하였다. 구강위생교육 4주 및 8주 후에 각 지수를 측정한 다음 시간 경과에 따른 전동치솔군과 수동치솔군의 구강위생 상태를 비교 분석하여 다음과 같은 결과를 얻었다. 1. 고정식 교정장치 부착 4주 후 치태지수, 치은염지수, 치은출혈지수 모두 증가 양상을 나타내었다. 2. 구강위생교육 후 치태지수, 치은염지수, 치은출혈지수 모두 감소 양상을 나타내었다. 3. 치은염지수, 치은출혈지수의 경우 감소양상이 수동치솔과 전동치솔군 간의 유의한 차이를 보이지 않았다. 4. 치태지수의 경우 수동치솔에 비해 전동치솔군에서 감소효과가 유의하게 크게 나타났다. 이상의 연구 결과는 고정식 교정장치로 치료받는 환자에서 전동치솔이 구강위생에 도움이 됨을 시사하였다. Patients with fixed orthodontic appliances frequently have increased levels of plaque accumulation leading to the possibility of gingivitis or enamel decalcification. Although many methods may be helpful in reducing dental plaque formation, the optimal mechanical removal of plaque is the most important factor during orthodontic treatment. The purpose of this study was to evaluate the efficacy of an electric toothbrush (with a specially designed orthodontic brush head) compared to a manual toothbrush in controlling plaque and gingivitis for patients with fixed orthodontic appliances. Oral hygiene status was measured in thirty-four patients using a plaque index, a gingival index and a bleeding index, before and four weeks after the attachment of fixed orthodontic appliances. Patients were randomly divided into two groups: electric and manual toothbrush groups. Oral hygiene instruction was given according to the type of toothbrush used. The Braun Oral-B D9511 with Braun Oral-B Ortho OD 15-1 brush head was used as the electric toothbrush while the Butler G.U.M. 124 was given as the manual toothbrush. After four and eight weeks, oral hygiene status was measured again. Through a comparison between the electric and the manual toothbrush groups, the following results were obtained. 1. All oral hygiene indices showed an increasing tendency after four weeks of fixed orthodontic appliance. 2. All indices presented a decreasing tendency four and eight weeks after oral hygiene instruction. 3. In case of the gingival index and bleeding index, the decreasing tendency did not show a statistically significant difference between the electric and the manual toothbrush groups. 4. The decreasing tendency of plaque index presented a statistically significant difference between the two groups, showing that the electric toothbrush was more effective in terms of oral hygiene. These findings suggest that an electric toothbrush is useful to orthodontic patients with fixed appliances.

      • SCIEKCI등재
      • SCOPUSKCI등재
      • SCIESCOPUSKCI등재

        Design and Implementation of Enhanced Resonant Converter for EV Fast Charger

        Suk-Ho Ahn,Ji-Woong Gong,Sung-Roc Jang,Hong-Je Ryoo,Duk-Heon Kim 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.1

        This paper presents a novel application of LCC resonant converter for 60kW EV fast charger and describes development of the high efficiency 60kW EV fast charger. The proposed converter has the advantage of improving the system efficiency especially at the rated load condition because it can reduce the conduction loss by improving the resonance current shape as well as the switching loss by increasing lossless snubber capacitance. Additionally, the simple gate driver circuit suitable for proposed topology is designed. Distinctive features of the proposed converter were analyzed depending on the operation modes and detail design procedure of the 10kW EV fast charger converter module using proposed converter topology were described. The proposed converter and the gate driver were identified through PSpice simulation. The 60kW EV fast charger which generates output voltage ranges from 50V to 500V and maximum 150A of output currents using six parallel operated 10kW converter modules were designed and implemented. Using 60kW fast charger, the charging experiments for three types of high-capacity batteries were performed which have a different charging voltage and current. From the simulation and experimental results, it is verified that the proposed converter topology can be effectively used as main converter topology for EV fast charger.

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