• 지질공학
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• 제26권4호
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• pp.515-529
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• 2016

본 연구에서는 제주 서귀포지역에서 산출되는 온천수 2지점과 탄산수 2지점에 대한 화학성분, CFCs (Chlorofluorocarbons) 동위원소, ${\delta}^{18}O$, ${\delta}D$, ${\delta}^{13}C$ 동위원소, 영족기체(He, Ne) 동위원소 분석을 통하여 탄산온천수와 탄산수의 수리화학적 특성, 생성연령, 영족기체의 기원과 $CO_2$ 가스의 기원을 해석하였다. 연구지역의 탄산수의 pH는 6.21~6.84의 범위의 약산성과 매우 높은 전기전도도 값($1,928{\sim}4,720{\mu}S/cm$)의 특성을 보인다. 화학적 유형은 $Mg(Ca,Na)-HCO_3$ 내지는 $Na(Ca,Mg)-HCO_3$ 유형을 보인다. 환경추적자인 CFCs 농도를 이용하여 지하수 연령측정결과, 탄산수는 약 47.5~57.2년, 지하수는 약 30.3~49.5년으로 추정되었다. 탄산수의 ${\delta}^{13}C$값은 -1.77~-7.27‰의 범위를 보여 $CO_2$ 가스의 기원은 심부기원과 일부 심부-무기기원의 혼합 기원으로 도시되었지만, 영족기체 조성비($^3He/^4He$, $^4He/^{20}Ne$)에서 헬륨가스가 심부기원의 농도가 절대적으로 높은 값을 보여 화산활동과 관련한 심부 마그마 기원임을 보여준다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.185-188
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• 2006

During the carbonation process in concrete, the rate of carbonation depends on porosity and moisture content of the concrete. For underground reinforced concrete structures, the interior concrete surface may be exposed to carbonation and the exterior concrete surface exposed to moisture due to wet soil or underground water. In this study, the permeability coefficients in mortar partially carbonated is derived as a function of carbonation depth and porosity of mortar by applying the so-called micro pore structure formation model (MPSFM) which was developed for the modeling of early-aged concrete. The permeability coefficient obtained from the micro-level modeling of carbonated mortar is verified with the results of accelerated carbonation test and water penetration test in cement mortar.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 추계종합학술대회 B
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• pp.123-125
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• 2008

치아의 에나멜 층은 85%의 탄산수산화인회석, 12%의 물 및 3%의 단백질 및 지질로 이루어져 있고, 덴틴 층은 47%의 탄산수산화인회석, 20%의 물 및 33%의 단백질 및 지질로 이루어져 있기 때문에 치아에 열이 가해지면 색이 변질된다. 치아 치료 등에서 고온이 적용될 경우에 열에 의한 치아 변색을 최소화하기 위해서 본 논문에서는 시간의 변화에 따른 온도에 의해서 치아 색의 변화 특성을 측정하였다. 특정 온도에서 시간의 변화에 따른 분광학적 광강도 특성을 알아보았다.

• 한국식품영양학회지
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• 제31권2호
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• pp.293-300
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• 2018

The purpose of this study was to investigate dietary habits, health lifestyle, preference and intake of beverages of Chinese students in Gyeonggi area. Therefore, we try to identify the factors that affect beverage consumption. According to the analysis of the demographic characteristics of male and female Chinese students, there were 155 male students (49.7%) and 157 female students (50.3%). There were statistically significant differences between the residence period and the time of coming to Korea according to sex (p<0.05), but there was no statistically significant difference between the education level, residence type and Korean ability (p>0.05). Analysis of the differences in health-related lifestyle among Chinese students of both sexes showed statistically significant difference in alcohol drinking, smoking, and exercise according to sex (p<0.05), but no statistically significant difference in computer use time (p>0.05). According to the analysis of the dietary habits of the Chinese students, there was a statistically significant difference in the number of meals per day, breakfast, lunch, dinner, snack frequency and number of midnight snacks, but no statistically significant difference in eating out frequency. As a result of the preference test for general beverages, 4.11 points of water, 3.81 points of milk, 3.64 points of fruit and vegetable juice, 3.58 points of tea, 3.25 points of coffee, 3.22 points of carbonated drinks, 2.92 points of functional drinks, respectively. Male students were more likely to prefer water, tea, and health functional drinks while female students had higher preference for fruit, vegetable juice and vinegar drinks (p<0.05). In general, consumption of regular drinks was 4.95 in water, 3.58 in milk, 3.03 in coffee, 2.92 in carbonated drink, 2.91 in fruit and vegetable juice, 2.63 in tea, 2.07 in functional drink, and 1.44 in vinegar appear. Male students had higher intake of water, tea, carbonated drinks, and health functional drinks while female students had higher intake of fruit and vegetable juice (p<0.05). The results of correlation analysis of factors affecting the general drinking of Chinese students are as follows. The intake of tea was related to the period of residence and dietary habits, the intake of milk for breakfast, the number of snacks and midnight snacks for carbonated drinks, and the fruit vegetable juice were related to dietary habits (p<0.01, p<0.05).

• Computers and Concrete
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• 제15권6호
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• pp.973-987
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• 2015

The electrical resistivity of air-dried, saturated, and carbonated concretes with different mixture proportions was monitored to evaluate and quantify the influence of the age of the specimen, carbonation, and curing condition. After 28 days of curing, four prepared specimens were stored in a vacuum chamber with 5% $CO_2$ for 330 days to make carbonated specimens. Four of the specimens were placed in water, and four specimens were cured in air until the end of the experiments. It was observed that the electrical resistivity of the carbonated specimens increased as carbonation progressed due to the decrease of porosity and the increase of hydrated products. Therefore, in order to estimate the durability of concrete, its carbonation depth was used as the measurement of electrical resistivity. Moreover, an increase of electrical resistivity for air-dried and saturated concretes was observed as a function of age of the specimen. From the relationship between chloride diffusivity provided by Yoon et al. (2007) and the measurements of electrical resistivity, it is expected that the results well be of significant use in calibrating chloride diffusivity based on regular measurements of electrical resistivity during concrete construction.

• 한국세라믹학회지
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• 제55권2호
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• pp.160-165
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• 2018

This paper investigates the reaction rate of $CO_2$ storing carbonation hybrid reaction by comparing the behavior of carbonation between $Ca(OH)_2$ and fly ash with that of CFBC (Circulating Fluidized Bed Combustion) containing plenty of Free-CaO. Because fly ash with CFBC contains a lot of unreacted CaO, it cannot be used as a raw material for concrete admixtures and its usages are limited. To reuse such material, we stabilized unreacted CaO by carbonation and investigated the carbonation rate. We used a pH meter and a thermometer to check the rate of the carbonization. Also, we set the contents of fly ash with CFBC, $Ca(OH)_2$, flow and fluid of $CO_2$, respectively, to 100 g, 50 g, 100 ~ 1000 cc/min and 400 g based on the content of Free-CaO. We used carbonated water instead of water, and added an alkaline activator to promote the carbonation rate. As a result, the addition of the alkaline activator and carbonated water promoted the rate of carbonation via a hybrid reaction.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.1053-1056
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• 2008

콘크리트의 투수계수는 콘크리트 구조물의 내구성능 및 미세구조의 밀실성을 판단하는 핵심적인 재료 매개변수이다. 투수계수를 산정하기 위한 많은 연구들이 있었으나, 시멘트 페이스트 및 골재 각각이 콘크리트의 투수성능에 미치는 영향을 다룬 연구는 드물다. 더우기, 탄산화가 염소이온의 확산계수에 큰 영향을 미칠 수 있음에도 불구하고, 탄산화된 콘크리트에 대한 확산계수를 다룬 연구는 더욱 드문 실정이다. 본 연구의 목적은 탄산화 및 비탄산화된 콘크리트의 투수계수를 추정할 수 있는 기초적 접근방법을 개발하는 것이다. 본 연구에서는 미세구조 모델 및 시멘트의 경화특성을 기초로 투수계수를 산정할 수 있는 해석적 기법이 개발되었다. 본 연구에서는 시간단계별로 변화하는 투수계수의 해석과 중성화된 콘크리트의 투수계수이다. 탄산화된 콘크리트에서 감소된 공극량이 계산되었으며 이는 투수계수의 산정에 이용되었다. 본 연구결과는 실험적 결과를 얻어서 상호 비교하여 검증하였다.

• 한국식품영양과학회지
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• 제23권3호
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• pp.420-428
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• 1994

The purpose of this study was to determine relationship among the observed frequencies of 12 beverages selected by college men and women according to sex, age, race and academic classification and to estimate consumption of milk according to sex, age, race and academic classification. The instrument consisted of a check list and four questions. The sample of 282 subjects, 149 college men and 133 college women, was made by the accidental choice method. Observations occurred in the university center cafeteria at the dinner meal. The significant relationship s were sex and race in association with beverage selections by all subjects. The proportion of men in the distribution who selected regular , carbonated soft drinks and the proportion of white students who selected any of the carobnated soft drinks were the influencies. The result of the study indicated that carbonated soft drinks were the most preferred items followed by milk, water, iced tea, fruit juices, coffee, cocoa, and tea.

• 한국가정과교육학회지
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• 제30권4호
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• pp.83-91
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• 2018

본 연구는 대전시에 위치한 고등학교 1, 2학년 여학생 235명을 대상으로 자기 기입식 기록법을 적용하여 주중 2일과 주말 1일, 총 3일간의 액체수분 섭취실태를 조사하였다. 액체수분 섭취총량은 838.5 ㎖/일(주중 790.5 ㎖/일, 주말 934.5 ㎖/일)로 2015 한국인 영양소 섭취기준에 제시된 충분섭취량 900 ㎖/일에 미치지 못하였다. 액체수분의 종류별 섭취량 분석 결과, 물의 섭취량이 611.6 ㎖/일로 가장 많았고, 탄산음료(65.7 ㎖/일), 우유(41.6 ㎖/일), 과즙음료(32.8 ㎖/일), 과채주스(25.4 ㎖/일)의 순으로 나타났다. 나머지 음료 8종은 섭취량이 15 ㎖/일 미만이었다. BMI 비만도에 따른 액체수분 섭취량 차이 분석에서 물과 액체수분 섭취총량은 BMI 23.0 이상인 학생이 18.5 미만, 18.5 이상 23.0 미만인 학생보다 많았다. 운동 빈도와 고염식 식습관에 따른 섭취량 차이 분석에서 운동 일수 3일/주 이상, 고염식 식습관 점수 7점 이상인 학생은 탄산음료의 섭취량이 많았다. 건강한 사람이라면 수분의 과잉 섭취로 인한 유해 효과가 없기 때문에 충분한 수분 섭취, 특히 건강 음료의 선택과 관련하여 올바른 교육이 필요하다고 할 수 있다.

• Nutrition Research and Practice
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• 제10권5호
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• pp.546-554
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• 2016

BACKGROUND/OBJECTIVES: The aim of this study was to investigate the perception of sugar reduction, nutrition education, and frequency of snacking in children according to the self-perceived dietary preferences for sweet taste by mothers in Busan. SUBJECTS/METHODS: A total of 277 mothers were surveyed, and their perceptions of sugar reduction and the frequency of snacking in children were assessed using a questionnaire. The subjects were classified into either a sweet (n = 91) or an unsweet (n = 186) group according to their self-perceived preferences for a sweet taste. RESULTS: In the sweet group, the results for sweet products were sweetened ice (86.8%), confectionery (74.7%), processed milk (73.6%), carbonated beverages (71.4%), and fermented milk (53.9%). In the unsweet group, the results were sweetened ice (88.7%), carbonated beverages (78.5%), processed milk (75.8%), confectionery (69.4%), and fermented milk (50.5%). The necessity of sugar intake reduction was high in both groups (sweet = 89.0%, unsweet = 82.8%). Beverage purchases after identifying the nutrition labeling was significantly lower in the sweet group than in the unsweet group (P < 0.05). The reasons for the beverage purchases instead of water were "habitually" (50.5%) and "like sweet taste" (25.3%) in the sweet group (P < 0.01). Snacking in children was significantly higher in the sweet group based on the increased frequencies of carbonated drinks (P < 0.01), fast food (P < 0.001), candy and chocolate (P < 0.05), crackers (P < 0.01), ramen (P < 0.01), and fish paste/hotdogs (P < 0.01). The frequency of purchase education after identifying the nutrition labeling was significantly lower in the sweet group than in the unsweet group (P < 0.01). CONCLUSIONS: These findings suggest that a perception of sugar reduction and practical nutrition education aimed at reducing the sugar intake are necessary to improve dietary habits.