• 대한지역사회영양학회지
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• 제29권1호
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• pp.65-80
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• 2024

Objectives: This study aims to compare changes in physical factors, health behaviors, eating habits, and nutritional intake among Korean male and female adults over a period of three years (2019-2021) before and after the outbreak of coronavirus disease 2019 (COVID-19). Methods: This study utilized raw data from the 8th Korea National Health and Nutrition Examination Survey (2019-2021). The participants in this study included 6,235 individuals in 2019, 5,865 individuals in 2020, and 5,635 individuals in 2021. Individuals whose daily energy intake was less than 500 kcal or exceeded 5,000 kcal were excluded from the study. Results: In comparison to 2019, overweight/obesity rates, weight, waist circumference, weekend sleep hours, and resistance exercise days/week increased in both male and female during the COVID-19 pandemic. Regarding eating habits, the proportions of people skipping breakfast, not eating out, consuming health supplements, and recognizing nutritional labels increased in 2020 and 2021, whereas the rate of skipping dinner decreased. Total energy intake has continued to decrease for the two years since 2019. A comparison of nutrient intake per 1,000 kcal before and after the outbreak of COVID-19 revealed that intake of nutrients, including protein, phosphorus, iron, vitamin A, riboflavin, and niacin increased, while folic acid intake decreased. In male, calcium, phosphorus, riboflavin, and niacin intakes increased, whereas iron, vitamin C, and folic acid intakes decreased. In female, phosphorus, iron, vitamin A, and riboflavin intake increased significantly, while protein and niacin intake decreased significantly. Conclusions: After COVID-19, the obesity rate, breakfast skipping rate, health supplement intake, and nutritional label use increased, while the frequency of eating out, dinner skipping rate, and total energy intake decreased. These environmental changes and social factors highlight the need for nutritional education and management to ensure proper nutritional intake and reduce obesity rates in the post-COVID-19 era.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제21권2호
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• pp.127-133
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• 2018

Purpose: For 3 consecutive years from 2012-2014, we analyzed the causative factors for why the Jeju Island had the highest obesity prevalences of school children among the 15 provinces in Korea. Methods: From our analysis of 28,026 elementary school children with obesity or normal weight in the 15 provinces, we analyzed 12 factors related to eating habits, exercise habits, lifestyle, and mental health. The differences between the obese and normal weight children were researched. Finally, Jeju was compared with Seoul, which has the lowest obesity prevalence in school age children. Statistical analysis was performed using the chi square test of PASW Statistics ver. 18.0. Results: Compared to the normal weight group, the obese group had significantly higher rates of consuming soft drinks (p<0.001), fast food intake (p=0.019), skipping breakfast (p<0.001), insufficient sleep (p<0.001), bullying experiences (p=0.001) and runaway impulses (p=0.012). Compared to Seoul, Jeju Island had significantly higher rates of Ramen intake (3.4% vs. 5.4%, p=0.021) and meat intake (46.0% vs. 52.9%, p=0.003). On the other hand, Jeju Island was significantly lower than was Seoul in their fruit intake (83.4% vs. 67.1%, p<0.001), vegetable intake (71.4% vs. 64.2%, p=0.001), and intense physical activity (63.4% vs. 47.7%, p<0.001). Meanwhile, insufficient sleep (15.4% vs. 9.6%, p<0.001) and runaway impulses (5.6% vs. 3.3%, p=0.027) in children were significantly lower in Jeju Island than in Seoul. Conclusion: The results of the obesity factor analysis of elementary school students in Jeju Island can be used as useful educational material for lowering the obesity prevalence in Jeju community.

• Journal of Nutrition and Health
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• 제28권1호
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• pp.23-32
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• 1995

This study was performed to investigate the influence of dietary fibers from the whole foods on the serum lipid level and bowel function in rats. The fiber sources of experimental diets were prepared by drying and milling of cereal(rice bran), vegetables(Korean cabbage, radish), fruit(apple), and sea weeds(laver, sea tangle). Each of fiber sources was mixed into the diet to make the 5% level of total dietary fiber. Male rats of Sprague-Dawley strain were blocked into 8 groups : FF, CC, CE, V1, V2, ER, S1, and S2. The animals were fed ad libitum each of experimental diets for 4 weeks. Serum triglyceride level was not significantly different among groups. The laver group showed the lowest level in the serum total cholesterol. The Korean cabbage group showed the highest level in the serum HDL cholesterol. The longest transit time was observed in the fiber free group and the shortest transit time was observed in the sea tangle group. Absorption rates of calcium were especially lower in the Korean cabbage and the sea tangle groups than the other groups. Magnesium and phosphorus absorption rates were influenced by SDF(Soluble Dietary Fiber) intake and TDF(Total Dietary Fiber) intake, respectively. Mucosa weight in the small intestine showed the tendency to increase by increasing of IDF (Insoluble Dietary Fiber) intake. especially the Korean cabbage group was the heaviest. The activity of maltase in the mucosa of small intestine was the lowest in the radish group.

• 대한지역사회영양학회지
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• 제25권1호
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• pp.32-47
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• 2020

Objectives: Calcium (Ca) is an insufficiently consumed nutrient, whereas phosphorus (P) intake has exceeded the recommended intake level in Korea over the past decade. The purpose of this study was to analyze dietary Ca and P intakes and their contribution rate according to dish groups. Methods: A 24-hour dietary recall survey of 640 healthy adults (aged 19-69 years) was undertaken twice in four Korean provinces. Dietary Ca and P intakes and their rates of contribution from 31 major dish groups were analyzed and compared by gender, age group, and region. Results: The average Ca and P intakes of the subjects were 542.1 ± 222.2 mg/d and 1,068.3 ± 329.0 mg/d, respectively. The intakes of Ca and P as percentages of recommended nutrients intake (RNI%) were 71.7 ± 29.8% and 152.6 ± 47%, respectively, and the percentages under the estimated average requirement were 60.3% for Ca and 3.8% for P. The RNI% of Ca was not significantly different between males and females, but was significantly higher in subjects in the sixties age group than in other age groups and was significantly lower in the Korean capital than in other regions. The RNI% of P did not significantly differ by gender or age groups, but it was significantly higher in the capital than in Gyeong-sang. The five major dish groups contributing to Ca intake (contribution rate) were milks/dairy products 69.2 ± 109.2 mg/d (12.6%), soups 55.6 ± 69.6 mg/d (10.1%), stir-fried foods 53.1 ± 70.7 mg/d (9.7%), stews 43.4 ± 85.4 mg/d (7.9%), and kimchi 38.4 ± 31.8 mg/d (7.0%). The five major dish group contributing to P intake (contribution rate) were cooked rice 160.7 ± 107.1 mg/d (14.9%), stir-fried foods 88.5 ± 89.4 mg/d (8.2%), soups 76.7 ± 85.8 mg/d (7.1%), one-dish meals 63.3 ± 94.4 mg/d (5.9%), and stews 62.6 ± 89.3 mg/d (5.8%). The dish groups contributing to Ca and P intakes differed somewhat by gender, age group, and region. Conclusions: Programs to improve the nutritional status of Ca and P intakes should consider the differences in Ca and P contribution rates by dish groups as well as by gender, age group, and region.

• International Journal of Fluid Machinery and Systems
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• 제3권4호
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• pp.285-291
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• 2010

To provide required flow rates of cooling or circulating water properly, approach flow conditions of vertical pump systems should be in compliance with state of the art acceptance criteria. The direct inflow should be vortex free, with low pre-rotation and symmetric velocity distribution. Physical model investigations are common practice and the best tool of prediction to evaluate, to optimize and to document flow conditions inside intake structures for vertical pumping systems. Optimization steps should be accomplished with respect to installation costs and complexity on site. The report shows evaluation of various approach flow conditions inside a compact waste water pumping station. The focus is on the occurrence of free surface vortices and the evaluation of air entrainment for various water level and flow rates. The presentation of the results includes the description of the investigated intake structure, occurring flow problems and final recommendations.

• 한국자동차공학회논문집
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• 제8권5호
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• pp.121-128
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• 2000

Simple design methods were developed to control the coolant flow rates through cylinder head gasket holes. Applying the concept of flow through an obstruction the ratio of intake to exhaust side flow rates could be easily controlled while maintaining the flow rates per cylinder of the original model. Flow distribution in the coolant passage of the original model was calculated by CFD and the flow rates at the gasket holes were modified based on the calculation results. The calculated flow rated of the modified gasket holes were reasonably close to target values. For more accurate control of the flow rate distribution, a design method with iterative CFD calculations was also suggested. The final size of gasket holes for the target flow rates were obtained just after a few optimization iterations. These methods can be very useful for the optimization of heat transfer characteristics in engine cylinder head and block.

• 환경생물
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• 제30권3호
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• pp.173-184
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• 2012

In order to investigate the fluctuation rates [FR] of phytoplankton after passage through a cooling system, the standing crops, chlorophyll a concentrations and carbon assimilation number of phytoplankton were surveyed at intake and outlet at Wolsong nuclear power plant [NPP] from July 2006 to June 2008. As a result, the total mean standing crops of phytoplankton were $1.0{\times}10^6\;cells\;L^{-1}$ and $7.3{\times}10^5\;cells\;L^{-1}$ at intake and outlet, respectively. The FR of phytoplankton by passage through the cooling system [PTCS] was 27.0%. Among them, the FR of microplankton and nanoplankton were 34.1% and 12.4%, respectively. In addition, the FR of diatoms and dinoflagellateswere 33.9% and 29.7%, respectively. These results showed the entrainment effects on microplankton and diatoms by PTCS were higher than those of nanoplankton and dinoflagellates. The FR of total chlorophyll a concentrations were 54.4%, and the FR of microplankton, nanoplankton and picoplankton were 58.9%, 38.5%, and 52.4%, respectively. So the entrainment effects on microplankton by PTCS were higher than those of nanoplankton and picoplankton. The mean FR of carbon assimilation number of phytoplankton was 57.6%, and the seasonal variations of FR of carbon assimilation number ranged from 47.5% to 76.8%. Our results indicated that the phytoplankton species responded differently to power plant operating conditions such as elevated temperature, chlorination, and mechanical impacts.

• Journal of Ecology and Environment
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• 제34권4호
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• pp.357-363
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• 2011

To examine factors affecting feeding efficiency of grey herons (Ardea cinerea), the foraging behavior was studied at a reservoir in Asan city, Chungcheongnam-do, South Korea during the breeding seasons (from April to July) of 2006 and 2007. Four factors (age of foraging birds, time of day, breeding stage, and microhabitat type) were analyzed. Adults were more efficient foragers than recently fledged juveniles, and they had a higher success rate than juveniles. About half of the adults caught large prey, whereas most juveniles caught only small prey. Adult grey herons had different feeding efficiency according to the breeding stage. Pecking and capture rates were high during the late period (fledging stage), and biomass intake rates were high during the early (incubating stage) and late periods. However, time of day had no significant effect on foraging activity of adult grey herons. Feeding activities of adult grey herons also showed significant variation among microhabitat types. Pecking and capture rates were higher in the submerged plants area, but capture success rate and biomass intake rate were not different according to microhabitat type.

• 한국분무공학회지
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• 제16권3호
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• pp.146-151
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• 2011

LPG(Liquified Petroleum Gas) fuel for vehicles has lots of advantages such as low emission level, cheaper fuel cost and enough infrastructure. Therefore it arouses interest as an alternative engine to reduce emission of diesel engines. Especially MPI(Multi Point Injection) type LPLi(Liquid Phase LPG injection) system could have overcome the disadvantages of mixer types such as low engine performance, decreased charging efficiency and cold starting difficulty. However ice formation on the nozzle tip and intake port due to the freezing of moisture around the components is often observed in LPLi systems. This icing phenomenon is the direct cause of unstable engine combustion, resulting in engine emissions. Therefore in this research, a spray visualization test for LPG injection was carried out to obtain the basic information of an LPLi injector, then the effects of butane and propane mixing rates on ice formation at the intake port and nozzle tip was investigated. As a result, the icing characteristics of them showed contrary results according to the mixing rates.

• Journal of Nutrition and Health
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• 제31권9호
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• pp.1404-1410
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• 1998

The purpose of this study was to investigate the effects of calcium intake levels on magnesium utilization in young and adult rats fed various levels of calcium(50, 100 or 200% of requirement) for 3 weeks. Feed intake, body weight gain, and feed efficiency ratios of the young group were significantly higher than those of the adult group. In calcium levels of tissues, serum calcium levels in young group were higher than in the adult group and kidney calcium levels in HCa(high-calcium group) were higher than in other groups. There was no significant difference in magnesium intake among age and diet groups. However, magnesium excretions through feces and urine in the adult group were higher than in the young group. Therefore, magnesium retention in the young group was higher than in the adult group. Especially in the young group, fecal magnesium excretion was increased with increasing levels of dietary calcium. Serum magnesium levels were lowest in YHCa(young 8t high-calcium) group, and there was no significant difference in liver and kidney levels among the calcium-diet groups. These results indicate that high calcium consumption promotes of fecal magnesium excretion and decreased magnesium retention rates in growing rats. Therefore, it is suggested that mineral interactions should be considered in the supplementation of dietary calcium intake for growth. (Korean J Nutrition 31(9) 1404-1410, 1998)