• 대한환경공학회지
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• 제33권5호
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• pp.307-313
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• 2011

본 연구는 고농도의 불소가 함유된 LCD 폐수를 처리하는데 있어, 칼슘원에 따른 제거 효율과 경제성에 부합되는 조건을 도출하여 실제 현장에 적용하는데 목적이 있다. 이를 위하여 칼슘원으로 $CaCl_2$, $Ca(OH)_2$ 및 $CaCO_3$를 이용하여 각각 pH, 칼슘주입량, 반응시간 및 교반속도의 변화에 따른 특성을 관찰하였다. 그 결과 $CaCl_2$의 경우 pH 7, 칼슘주입량 0.4[Ca]/[F] (mol / mol), 1시간, 200 rpm으로 결정되었고, $Ca(OH)_2$의 경우 pH 7, 칼슘주입량 30 mL/L, 1시간, 200 rpm으로 결정하였으며, $CaCO_3$의 경우 pH 4, 칼슘주입량 30 mL/L, 1시간, 200 rpm으로 적용하는 것이 최적조건이라고 판단되었다. 그러나 현장의 상황에 따라 적용 조건의 변경이 가능하다.

• Journal of Community Nutrition
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• 제6권2호
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• pp.67-77
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• 2004

In order to investigate the differences of nutrient intakes by the economic status and different age groups and to identify the nutritional risk group and its specific nutrition problem, 2001 Korean National Health and Nutrition Survey were analyzed. The subject's numbers of 9,391 were classified into four classes such as low (14.2%), medium (37.2%), high (26.0%), and high above (22.6%) on the basis of the family monthly income and the 2001 Korean minimum cost of living according to the family size. Mean intakes of energy and all nutrients assessed by the RDAs, lipid-energy %, and MAR were increased as the economic status were going up. Na intake expressed per 1,000kcal was in reverse. Nearly a half(45.5%) of the low-income people seemed to take nutritionally inadequate diet in consideration with MAR values. Deficiencies of iron and even energy in the toddlers (1 to 2 years) of low-income class were of great concern. Adolescent age group has been observed that their calcium and iron intakes, and possibly energy, were appeared to be the most deficient among all the age groups regardless of the economic status. For the elderly in all the economic status except high-above class, calcium, vitamin A, and riboflavin were commonly deficient nutrients. Calcium deficiency was appeared throughout nearly all the ages except toddlers and all the economic classes. Even in the high-above class 57.3% took insufficient amount of calcium.

• Computers and Concrete
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• 제8권5호
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• pp.583-595
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• 2011

This paper studied the cement efficiency factor (k factor) of high calcium Class F fly ash. This k factor represents a unit of fly ash with efficiency equivalent to k unit of cement. The high calcium Class F fly ash was used to replace cement in concrete. The modified Bolomey's law with linear relationship was used for the analysis of the result of compressive strength, cement to water ratio (c/w) and fly ash to water ratio (f/w) by using the multi-linear regression to determine the k factor and other constants in the equations. The results of analysis were compared with the results from other researcher and showed that the k factor of high calcium Class F fly ash depends on the fineness of fly ash, replacement level and curing age. While the amount of CaO content in Class F fly ash not evident. Furthermore, necessary criteria and variables for the determination of the k factor including the use of the k factor in concrete mix design containing fly ash were proposed.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 봄 학술논문 발표대회
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• pp.144-145
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• 2021

Calcium silicate hydrate(C-S-H) is the principal binding phase that controls the strength and thermal stability of concrete. However, the effects of high temperature on the lattice structure and interatomic structure of C-S-H remains poorly understood due to its nanocrystallinity. This study aims to elucidate the change in interatomic distance of synthetic C-S-H with different Ca/Si molar ratios after exposure to high temperature via high energy X-ray scattering experiment which is a powerful analytical tool for amorphous materials.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 추계 학술논문 발표대회
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• pp.113-114
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• 2017

In this study, the change of composition of cement hardened at high temperature through XRD was observed. The specimen was made of cement paste and the heating rate condition was applied at rapid thermal annealing (10.0℃ / min). The decrease of calcium hydroxide was not confirmed, but the calcium carbonate tended to be impossible or decreased after 800℃. Calcium silicate and larnite were observed to increase with increasing temperature. It is considered that silicic acid, which is a stable structure due to the decomposition of calcium silicate, is changed into a phase such as lime.

• Journal of Dairy Science and Biotechnology
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• 제28권1호
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• pp.17-28
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• 2010

A substantial body of evidence has emerged over the last decade in support of the novel concept that dietary calcium and dairy foods play an important role in regulating energy metabolism and thereby promote healthy weight management and reduce obesity risk. This concept has been demonstrated in experimental animals studies, cross-sectional and prospective population studies and a number of randomized clinical trials. Notably, the effects of dairy foods in weight management are more consistent than the effects of supplemental calcium across clinical trials, and calcium per se is responsible for approximately 40-50% of the effects of dairy. The calcium component is only effective in individuals with chronically low calcium intake, as it serves to prevent the endocrine response to low calcium diets which otherwise favors adipocyte energy storage; calcium also serves to promote energy loss via formation of calcium soaps in the gastrointestinal tract and thereby reduce fat absorption. The calcium-independent anti-obesity bioactivity of dairy resides primarily in whey. The key components identified to date are leucine and bioactive peptides resulting from whey protein digestion. The high concentration of leucine in whey stimulates a repartitioning of dietary energy from adipose tissue to skeletal muscle where it provides the energy required for leucine-stimulated protein synthesis, resulting in increased loss of adipose tissue and preservation of skeletal muscle mass during weight loss. Finally, dairy rich diets suppress the oxidative and inflammatory responses to obesity and thereby attenuate the diabetes and cardiovascular disease risk associated with obesity.

• Journal of Nutrition and Health
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• 제10권4호
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• pp.104-110
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• 1977

Vegetables are liberally taken to enhance the mineral, vitamin, and rouphage value of the diet. And calcium is an essential mineral at all ages, although the daily requirement varies with physiological status of the individual. On the other hand, oxalic acid is an unwanted constituent of several clinical disorders. It is therefore necessary to take into account the calcium as well as the oxalic acid content of the various calcium, foods. Oxalic acid, calcium, calcium/oxalic acid ratio and available calcium have been determined in 31 kinds of the Korean common vegetables. The results are summarized as follows; 1. The highest content of oxalic acid has been recorded in Amaranth. spinach and beet. It is respectively 1,100mg%, 619mg%, 550mg% in fresh sample. It is comparatively high in Leek, leavels of perilla, Mugwort, Chyi-leaves, green red pepper, Burdock. 2. Many vegetables have been calculated as below 2.0 in the calcium/oxalic acid ratio. 3. Avaiable calciumis much in Malaolitoria, Lettuce, Green onion whole, Green garlic, Wild onion, Cabbage and Radish root. 4. A food calendar is suggested as a guide to the proper selection of food items for normal individuals and for those suffering from urolithiasis, cardiovascular disease or calcium deficiency status.

• Journal of Nutrition and Health
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• 제25권7호
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• pp.597-607
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• 1992

The present study examined effects of caffeine on coronary circulation myocardial oxygen me-tabolism and calcium release in isolated perfused guinea pig hearts. Intracoronary caffeine({{{{ {10 }^{-5 } }}}}∼{{{{ { 10}^{-3 } }}}}M) was employed for 10 minutes to measure coronary perfusate flow(CF) and coronary vascular sresistance(CVR) at a constant coronary perfusion pressure of 80 cmH2O Perfusate myocardial oxygen consumption(MVO2) and percent oxygen extraction(%EC2) were calcula-ted. In addition calcium contents in both perfusate samples were measured to calculate calcium release in coronary venous effluent. Caffeine significantly decreased CF and increased CVR during 10 minutes of caffeine perfusion regardless of dose of caffeine perfused exhibiting time-response. While % EO2 was significantly enhanced with caffeine MVO2 was markedly reduced. The coronary venous perfusate pH dcreased during the perfusion with caffeine. These changes were consistent with caffeine-induced metabolic acidosis. Calcium release appeared to be dose-dependent and high dose of caffeine greatly increased venous calcium release even 2 minutes after perfusion with carffeine. These finding in dicate that caffeine produced coronary vasoconst-riction with increased calcium release in isolated perfused guinea pig hearts. Additionaly this vasoconstrictor response mignt be due tin part to the direct actions of caffeine.

• 한국생활과학회지
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• 제9권3호
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• pp.395-403
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• 2000

This study was carried out with 200 students of Chungbuk National University to investigate their dietary behavior and calcium intake and to find out variables among general characteristics of subjects which influence dietary behavior and calcium intake. Questionaires and interviews were used for data collection. The results obtained were as follows: 1) Dietary behavior of college students were not desirable as a whole. The percentages of skipping breakfast and irregular meal among students were over one third, respectively. Especially students living alone skipped breakfast more frequently, took their meals more irregularly, and their eating frequencies of 6 food groups were lower compared to students eating at home. 2) Calcium intake was significantly different according to gender. Mean calcium intake of male students was 744.0 mg/day and that of female students was 480.8 mg/day. Average %RDA of calcium intake of female students was 68.5%. Resource food contributing to calcium intake in the first order was milk, next was yogurt, Small anchovies, kimchi made with Chinese cabbage, ice cream and soybean curd in that order. From the results of this study, we found that the students living alone and female students are exposed to high risk of poor dietary behavior and undernutrition of calcium. In conclusion, nutrition education programs for them are required as soon as possible.

• 한국수산과학회지
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• 제36권2호
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• pp.74-79
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• 2003

The functional properties such as a firming maintenance capacity for fermented vegetables, protein coagulation capacity antibacterial activity, calcium and peroxide absorption capacity of calcium powder of cuttle bone treated with acetic acid (ATC) were examined. In the Korean pickled cucumbers (20 days), the calcium content of ethanol insoluble solids was 5,264.9 mg/100 g and this value was higher than that of control (2,036.4 mg/100 g). Protein coagulation capacity of ATC was $0.9\%$ and its calcium absorption capacity was $49.3\%.$ The peroxide absorption capacity of ATC was shown $0-1.1\%$ range. Antibacterial activity was detected above $0.2\%.$ The ATC was effective in a firming maintenance of fermented vegetables (cucumber), coagulation capacities for soybean milk and antibacterial activity. The ATC was not effective in clarifying wastewater. Peroxide absorption capacity toward linoleic acid could not be checked by ATC, but its calcium absorption ratio was high compared to that of commercial calcium powder.