• 한국식품과학회지
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• 제18권1호
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• pp.6-10
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• 1986

Tetrachloroisophthalonitrile로 저장된 또는 저장중 훈증처리한 양파는 대조구보다 중량감소는 1/2로 줄일 수 있었으며 비훈증처리구에서 RH 80%로 저장한 양파는 RH 90%보다 중량감소가 적었으나 훈증처리한 양파에서는 거의 차이가 없었다. 저온저장시($0^{\circ}C$) 양파의 발근 및 외부발아는 나타나지 않았고 호흡량의 $Q_{10}$값은 $1.9{\sim}2.1$의 범위였다. 양파 저장중 중량감소와 부패율은 저장기간이 경과함에 따라서 정의 상관관계로 나타났으나 호흡량은 변화가 적어서 양파 저장중 중량감소는 호흡생리에 의한 것 보다는 부패에 의한 감소가 지대함을 알 수 있었다.

• 한국환경농학회지
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• 제14권1호
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• pp.7-14
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• 1995

하천 수질관리 모델인 QUAL2E를 남강에 적용한 결과는 다음과 같다. 1. 모델변수의 민감도 분석 결과는 BOD, DO의 경우 BOD decay rate constant, 영양염류인 경우 Org-N oxidation rate constant, $NH_3-N$ oxidation rate constant, Org-P decay rate constant가 각 수질인자에 중요한 변수로 작용하였다. 2. 모델보정 결과를 보면 실측치와 예측치의 상관성은 DO, BOD의 경우 r=0.93, 0.94로 높은 상관성을 보였으며 영양염류인 경우는 질산성 질소가 r=0.61이었으나, 그 외는 r=0.90 이상으로 나타났다. 3. 모델검증 결과는 보정시보다 상관성이 떨어졌으나 DO, $NO_3-N$의 경우 r=0.68, 0.45로 낮고 그 외는 r=0.75이상으로 높은 편으로 나타났다. 4. 유량과 부하량의 변화에 대하여 하류 40.5 Km 이후의 BOD 농도변화는 적었으나, 하수종말처리장 건설이후 유량과 부하량을 변화시켜 수질농도를 예측한 결과 하류 40.5 Km 이후는 함안천의 영향을 받을 것으로 예측되었다.

• International Journal of Vascular Biomedical Engineering
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• 제1권2호
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• pp.13-19
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• 2003

Endothelial release of nitric oxide (NO) contributes to the regulation of vascular tone by inducing vascular relaxation. To estimate the blood flow-dependent nitric oxide level and half-life (T1/2) of nitric oxide in vivo state, we investigated the change of aortic NO currents during the change of aortic blood flow rate using NO-selective electrode system and electromagnetic flowmeter in the aorta of anesthetized rats. Resting mean aortic blood flow rate was $49.6{\pm}5.6ml/min$ in the anesthetized rats. NO currents in the aorta were increased by the elevation of blood pressure and/or blood flow rate. When the aortic blood flow was occluded by the clamping, aortic NO currents were decreased. The difference of NO concentration between resting state and occluded state was $1.34{\pm}0.26{\mu}M$ (n=7). This NO concentration was estimated as blood flow-dependent nitric oxide concentration in the rats. Also, while the aortic blood flow was occluded, NO currents were decreased with exponential pattern with $12.84{\pm}2.15$ seconds of time constant and $7.70{\pm}1.07$ seconds of half-life. To summarize, this study suggested that blood flow-dependent NO concentration and half-life of nitric oxide were about $1.3{\mu}M$ and 7.7 seconds, respectively, in the aorta of anesthetized rats. The nitric oxide-selective electrode system is useful for the direct and continuous measurement of NO in vivo state.

• Bulletin of the Korean Chemical Society
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• 제35권3호
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• pp.833-838
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• 2014

The energy- and time-dependent branching to the competing dissociation paths are studied by theory for coupled unimolecular dissociations of the o-, m-, and p-chlorotoluene radical cations to $C_7{H_7}^+$ (benzylium and tropylium). There are four different paths to $C_7{H_7}^+$, three to the benzylium ion and one to the tropylium ion, and all of them are coupled together. The branching to the multiple paths leads to the multiexponential decay of reactant with the branching ratio depending on both internal energy and time. To gain insights into the multipath branching, we study the detailed kinetics as a function of time and internal energy on the basis of ab inito/RRKM calculations. The number of reaction steps to $C_7{H_7}^+$ is counted for each path. Of the three isomers, the meta mostly goes through the coupling, whereas the para proceeds with little or no coupling. In the beginning, some reactants with high internal energy decay fast to the benzylium ion without any coupling and others rearrange to the other isomers. Later on all three isomers dissociate to the products via long-lived intermediates. Thus, the reactant shows a multiexponential decay and the branching ratio varies with time as the average internal energy decreases with time. The reciprocal of the effective lifetime is taken as the rate constant. The resulting rate-energy curves are in line with experiments. The present results suggest that the coupling between the stable isomers is thermodynamically controlled, whereas the branching to the product is kinetically controlled.

• 한국치위생학회지
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• 제10권2호
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• pp.361-374
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• 2010

Objectives : The purpose of this study was to provide some basic data for effective prevention and oral health education for oral health. For that purpose, a self-administered questionnaire was distributed to the boys of three high schools in Gyeonggi Province. Methods : The questionnaire consisted of items about the practice of oral health control and knowledge of decay according to grade, number of snacking, preferred taste, and toothbrushing. Total 487 questionnaires were put to analysis using the SPSS WIN 13.0 program. Results : 1. The biggest number of the boys brushed their teeth twice a day. The 10th graders brushed teeth three times a day, and the 11th and 12th graders tended to brush teeth twice a day(${\chi}^2$=18.21, p<.05). 2. As for the way of toothbrushing, 39.0% of the boys said they brushed teeth the way they felt like, being followed by those who said they brushed teeth turning the toothbrush up and down and brushing both the teeth and gums(32.6%). As for the number of snacking, those who had snacks three times a day or more brushed teeth turning the toothbrush up and down and brushing both the teeth and gums. Those who hardly had snacks more tended to brush teeth the way they felt like than those who had snacks(${\chi}^2$=21.28, p<.05). And as for preferred tastes, those who preferred a sweet and salty taste more tended to brush teeth the way they felt like than others. And those who preferred a hot taste brushed teeth turning the toothbrush up and down and brushing both the teeth and gums(${\chi}^2$=26.85, p<.01). 3. The respondents' percentage of correct answers for 'Decay is caused by bacteria' was 81.5%. Those who preferred a hot taste recorded the highest percentage of correct answers(${\chi}^2$=21.95, p<.00). 4. Their percentage of correct answers for 'Decay is accompanied by pain from the beginning' was 78.2%. The 12th graders had the highest rate of correct answers, and the 11th graders had the highest rate of wrong answers(${\chi}^2$=11.56, p<.00). 5. Their percentage of correct answers for 'Fluorine is helpful to the prevention of decay' was 75.4%. Those who hardly had snacks recorded the highest rate of correct answers(${\chi}^2$=10.05, p<.02). 6. Their percentage of correct answers for 'There is a way to supply fluorine into the waterworks' was 29.2%, which means the percentage of wrong answers was much higher. The percentage of wrong answers was the highest in the 11th grade(${\chi}^2$=7.06, p<.03). 7. The respondents' mean scores of knowledge of decay were 13.15 of total 18. While the 12th graders showed the highest level of knowledge of decay, the 11th graders were lower in the level of knowledge of decay than the other graders. And there were significant differences(F=5.41, p<.01) according to grade with no such differences according to the number of snacking and preferred taste. Conclusions : Oral health education should be applied to the boys all through their life to have a great effect, and it is important that they should always put the oral health education into practice to be a successful education.

• 대한환경공학회지
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• 제27권4호
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• pp.409-413
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• 2005

본 논문에는 자가영양균의 최대비성장율 추정법이 제시되었다. 먼저 질산화균의 농도가 질산화 된 암모니아, 슬러지 일령 및 사멸계수를 이용하여 시뮬레이션 되었고, 다음단계로 과잉암모니아를 공급하여 질산화균의 호흡율을 측정하였다. 자가영양균의 최대비성장율은 ${\mu}_{max,A}\;=\;OUR_{max,A}/Y_A$의 관계를 통해 계산되어질 수 있으며 추정된 최대비성장율은 운전기간에 걸쳐 일정한 값을 가지지 앉고 시간에 따라 변화한다는 결과를 얻었다. 본 연구를 통해 최대호흡율을 이용한 최대비성장율의 동적 추정법이 수행되었고, 일정한 최대비성장율를 이용한 처리장 운전결과 예측은 처리장 거동을 예측할 수 없으며 활성슬러지공정의 성능예측을 위한 시뮬레이션을 위해서는 동적 추정된 매개변수의 사용이 필요함을 확인하였다.

• 한국환경보건학회지
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• 제31권4호
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• pp.260-265
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• 2005

Indoor air quality might be affected by source strength of indoor pollutants, ventilation rate, decay rate, outdoor level, and so on. Although technologies measuring these factors exist directly, direct measurements of all factors are not always practical in most field studies. The purpose of this study was to develop an alternative method to estimate the source strength and deposition constant by application of multiple measurements. For the total duration of 60 days, indoor and outdoor $NO_2$ concentrations every 3 days were measured in 30 houses in Seoul, Asan and Daegu. Using a compartment model by mass balance and linear regression analysis, penetration factor (ventilation divided by sum of air exchange rate and deposition constant) and source strength factor (emission rate divided by sum of air exchange rate and deposition constant) were calculated. Subsequently, the source strength and deposition constant were estimated. Natural ventilation was $1.80{\pm}0.42\;ACH,\;1.11{\pm}0.50\;ACH,\;0.92{\pm}0.26\;ACH$ in Seoul, Asan and Daegu, respectively. Calculated deposition constant(K) and source strength of $NO_2,$ in this study were $0.98{\pm}0.28\;hr^{1}\;and\;16.28{\pm}7.47\;ppb/h,$ respectively.

• 한국안전학회지
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• 제23권5호
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• pp.49-53
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• 2008

Glow discharge has lots of attractive properties, such as lower discharge sustaining voltage, no generation of ozone, and so on. And more, ionizer was developed recently using an atmospheric pressure glow discharge. On the other hand, ionizer needs a compressed or blown air to transport ion for charged objects. This air is very useful in explosive hazardous area to prevent the explosion of flammable gas and/or vapor by ignition sources, e.g. electrical spark. In this paper, we investigated the ionizing characteristic of atmospheric pressure glow discharge by controlled air flow rate from 5 liters to 60 liters a minute, and compared with decay time between the corona discharge and glow discharge as a function of some direction and distance from discharge ion source. We confirmed that an air flow rate needs 25 liters a minute to sustain the most suitable atmospheric pressure glow discharge and to increase an ionizing efficiency.

• 한국치위생학회지
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• 제4권2호
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• pp.165-177
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• 2004

The purpose of this study was to analyze the influence of child's general property, mother's social and economic property, mother's knowledge and behavior in oral hygiene upon the appearance and treatment of child's primary tooth decay. For the purpose, oral examination was applied to one hundred three(103) small children who were at the age between four(4) and seven(7) and went to two(2) places of day care centers located in Seoul, and questionnaire was done to their mothers. The results of the study are as follows. 1. The number of children's dt is 1.55, the number of their ft is 1.42, dft index for primary tooth is 2,98, ft rate is 45.61%, and the higher child's age is, the higher their value is. 2. Mother's age, educational background, and occupation does not show significant difference with dft index for primary tooth. The higher mother's monthly average income is, the higher child's ft rate is. 3. dft index for primary tooth does not show significant difference according 10 mother's knowledge in oral hygiene. And, the child of mother using dental floss does show higher it rate in comparison with the one of mother who does not use dental floss, 4. Experience using dental clinic to treatment tooth decay does show significant difference with dft index for primary tooth. And experience using dental clinic for the purpose of oral examination and preventive treatment does show significant difference with ft rate. 5. From the result of multiple regression with dependent variable of dft index for primary tooth, there is no variable having significant influence. From the result of multiple regression with dependent variable of ft rate, explanatory variable is 43%, child's age, mother's occupation, mother's monthly average income, and experience using dental clinic to prevent tooth decay are significant explanatory elements. Through the above results, we can know that mother should practice positive behavior in oral hygiene for child to improve oral health. Under the reason, oral health education should be applied toward mothers as soon as possible, and governmental support should be followed so that mothers can participate in the education.

• 농업과학연구
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• 제22권1호
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• pp.42-48
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• 1995

시베리아 및 카나다산(産) 수입침엽수(輸入針葉樹) 4수종(樹種)에 대하여 고유(固有)의 내후성(耐朽性) 및 CCA계(系) 목재방부제(木材防腐劑) 최적처리량(最適處理量)을 검토하기 위하여 약액농도(藥液濃度)를 달리하여 처리(處理)한 후 수종별(樹種別) 약제흡수량(藥劑吸收量), 강제부후시험(强制腐朽試驗)에 의한 중량감소율(重量減少率), 주사전자현미경(走査電子顯微鏡) 관찰(觀察)에 의한 부후형태(腐朽形態) 등을 조사(調査)하였다. 수종별 약제흡수량(藥劑吸收量)은 카나다산(産) 수종(樹種)에 비하여 비중(比重)이 높고 연륜폭(年輪幅)이 좁은 시베리아산(産) 수종(樹種)이 적은 약제흡수량(藥劑吸收量)을 나타내었으며 무처리재(無l處理材)의 고유(固有)의 내후성(耐朽性)을 조사한 결과 갈색부후균(褐色腐朽均)인 부후개떡버섯에 비하여 자색부후(自色腐朽)균인 구름버섯에 대하여 낮은 경향(傾向)을 보였다. 수입침엽수(輸入針葉樹) 4수종(樹種)에 대한 CCA계(系) 목재방부제(木材防腐劑)의 최적(最適) 처리농도(處理濃度)는 효력치(效力値) 80(구름버섯) 및 90(부후개떡버섯)이상(以上)을 나타낸 0.7%가 적절한 것으로 판단되며 이때의 약제(藥劑) 흡수량(吸收量)은 $3.8-5.5kg/m^3$이었다. 부후형태(腐朽形態)를 관찰(觀察)한 결과 무처리재(無處理材)의 경우에는 가도관(假道官) 내강(內腔)에 균사(菌絲)가 침입(侵入)해 있고 가도관(假道官) 벽(壁)에 천공(穿孔)이 형성(形成)되었으며 유록벽공(有綠壁孔)의 벽공록(壁孔綠) 및 방사조직(放射組織)이 분해(分解)되어 고유(固有)의 형태(形態)를 상실(喪失)하였으나 농도(濃度) 0.5% CCA처리재(處理材)의 경우에는 거의 건전(健全)한 형태(形態)를 유지(維持)하고 있어 부후(腐朽)의 진행(進行)이 인정(認定)되지 않았다.