• Transactions of the Korean Society of Mechanical Engineers B
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• v.21 no.7
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• pp.948-961
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• 1997

The effects of intake port eccentricity and a partition between the two intake ports on the incylinder swirl characteristics in a 4 valve diesel engine having the two intake ports, one is a helical intake port and the other is a tangential intake port, were investigated by using the impulse swirl meter(ISM) in a steady flow test rig. Mean flow coefficient ( $C_{f(mean)}$, swirl ratio ( $R_{s}$) and the mass flowrate through the two intake ports with and without intake port partition were measured. The results showed that the characteristics of in-cylinder swirl ratio formed by a 4-valve cylinder head were largely affected by valve eccentricity ratio ( $N_{y}$) and the existence of an intake port partition between the two intake ports. Mean flow coefficient ( $C_{f(mean)}$) increases and swirl ratio ( $R_{s}$) decreases in case of being the partition between the two intake ports. And also the mass flowrate through the tangential intake port is 19.0% and 7.7% more than that of the helical intake port in case of the two intake ports with and without partition respectively.ively.

• Journal of Nutrition and Health
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• v.40 no.2
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• pp.154-161
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• 2007

This study investigated the effects of xylooligosaccharide on feces bifidobacteria proliferation, lactic acid concentration and lipid metabolism in healthy woman. Fourteen volunteers were randomly assigned to 2 groups : 1.4 g/day xylooligosaccharide intake group, 2.8 g/day xylooligosaccharide intake group. The duration of the study was 28 days. The amount of feces and excretion time were not affected by xylooligosaccharide intake. The color of feces changed to yellow brown, and hardness of stool and effort to evacuation were reduced by xylooligosaccharide intake. Xylooligosaccharide intake reduced the fecal pH significantly after 14 days in 2.8 g/day intake group (p < 0.05). The number of fecal bifidobacteria were significantly increased after 28 days in 1.4 g/day intake group (p < 0.05), and in 2.8 g/day intake group, the number of fecal bifidobacteria significantly increased after 14 days (p < 0.05). Water contents of feces were not affected by xyloolgosacchride intake. The fecal triglyceride and cholesterol concentrations were increased in 2.8 g/day intake group (p < 0.05), and in 1.4 g/day intake group, fecal cholesterol concentration only was increased (p < 0.05). The fecal lactic acid concentration was significantly increased in 2.8 g/day intake group (p < 0.05). Serum trigly-ceride, cholesterol and glucose concentration were significantly decreased in 2.8 g/day intake group (p < 0.05). In conclusion, xylooligosaccharide dietary supplementation may be beneficial to gastrointestinal health and lipid metabolism, and 2.8 g/day intake was more effective than 1.4 g/day intake.

• Journal of Nutrition and Health
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• v.38 no.4
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• pp.320-326
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• 2005

This study was conducted to estimate dietary choline intake of Koreans according to gender, age and region by using the data on per capita food intake in 1998 and 2001 and the data on choline contents of foods customarily eaten by Koreans. Sixty-four and 97 kinds of food items were used for the estimation of choline intake in 1998 and 2001, respectively. And these corresponded to approximately $90\%$ of the total amount of food intake and energy intake. Based on these food items and choline content, per capita choline intake of Koreans was estimated to be 623.0 mg and 602.4 mg in 1998 and 2001 respectively , 687.2 mg and 659.1 mg in 1998 and 2001 for male, 560.2 mg and 551.0 mg in 1998 and 2001 for female. While the number of foods considered in estimation was higher in 2001 than 1998, choline intake was lower in 2001. The estimated per capita choline intake of male population was higher than that of female population by 108-127 mg, possibly due to the difference in total amount of food intake. The age group with the highest choline intake was different between 2 time points. Although adolescents of 13- 19 years showed the highest intake (712.0 mg) in 1998, mid-aged adults of 30-49 years showed the highest choline intake (662.2 mg) followed by adolescents (645.7 mg) in 2001. In regional comparison, choline intake of the rural population (588.7 mg and 588.3 mg in 1998 and 2001 respectively) was lower than that of population in small to medium-size cities (625.1 mg and 603.9 mg) or in metropolitan cities (637.7 mg and 602.8 mg). This result revealed that per capita choline intake of the Korean population falls within the adequate range with some differences by age, sex and residing area.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.17 no.3
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• pp.178-185
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• 2014

Purpose: The use of dietary supplements (DS) has increased in most nations. We investigated the amount of DS intake in the Korean population by analyzing a national survey, to support the preparation of a national institutional strategy regarding DS intake and marketing. Methods: The data of the fifth Korea National Health and Nutrition Examination Survey (a year between 2010 and 2012) were investigated, analyzing the rate of DS intake, and the characteristics of the intake group and non-intake group in Korean preschool children. Results: The intake rate of DS was 49.0-54.2% (1,313,874-1,491,240) and 19.6-30.3% (250,603-421,922) in children from 1 to 6 years old and in those less than 1 year, respectively, from 2010 to 2012. The highest intake rate was observed in the age group of five. The mean age was significantly higher in the DS intake group than in the non-intake group. Intake of essential nutrients, minerals, and vitamins were also higher in the DS intake group. The level of family income was significantly associated with the intake rate (p<0.001). In children less than 1 year, probiotics accounted for the highest intake of DS. Conclusion: Korean preschool children have high consumption of DS. Therefore, problems may arise from the waste of money purchasing unnecessary DS, and from the overuse of DS in preschoolers who do not require DS intake. We hope these results can be used to produce an appropriate national institutional strategy regarding DS intake and marketing.

• Korean Journal of Community Nutrition
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• v.21 no.4
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• pp.344-353
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• 2016

Objectives: New retinol activity equivalent (RAE) was introduced as vitamin A unit in Dietary Reference Intake (DRI) for Koreans 2015. The purpose of this study was to evaluate the adequacy of 2015 reference intake (RI) of vitamin A in RAE unit by the comparison with RI and dietary intake of vitamin A. Methods: Analyses on RI of vitamin A were based on the Recommended Dietary Allowances (RDA) for Koreans (1962~2000) and DRIs for Koreans (2005~2015). Analyses on Koreans dietary intake of vitamin A were based on the Korea National Health and Nutrition Examination Survey (KNHNES) reports (1969-2014). For recalculation of RI and dietary intake of vitamin A in RE to RAE, 2013 Koreans intake of retinol: carotenoids ratio of 13: 87 was applied. Results: RI of vitamin A was 600~750 RE for Korean adult, and 339~425 RAE when calculated by applying the retinol and carotenoids intake ratio. Vitamin A intakes of Koreans were <100% RI, 267~668 RE from 1969 to 2001. From 2005, vitamin A intake had increased to >700 RE, >100% RI. When vitamin A intake was converted from RE to RAE (2005~2014), 718~864 RE became 405.8~488.1 RAE, decreased to 56.5% level. The recent 2015 RI of vitamin A is 850 RAE, two times of 2005 & 2010 RI of 425 RAE for adult male. Conclusions: When nutritional status of vitamin A was assessed for Koreans using the estimated average requirement (EAR) of 2015 (570, 460 RAE for male, female adults, respectively), ratio of deficient people increased significantly when judged based on the previous intake of Koreans, <490 RAE. We needs to examine the 2015 RI (EAR) of vitamin A, find a way to measure the accurate intake of dietary vitamin A, and to increase the dietary intake of this vitamin.

• Journal of the Korean Society of Safety
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• v.33 no.4
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• pp.119-126
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• 2018

In recent years, as flood damage caused by heavy rains increased, the great-depth tunnel using urban underground space is emerging as a countermeasure of urban inundation. The great-depth tunnel is used to reduce urban inundation by using the underground space. The drainage efficiency of great-depth tunnel depends on the intake design, which leads to increase discharge into the underground space. The spiral intake and the tangential intake are commonly used for the inlet facility. The spiral intake creates a vortex flow along the drop shaft and reduces an energy of the flow by the wall friction. In the tangential intake, flow simply falls down into the drop shaft, and the design is simple to construct compared to the spiral intake. In the case of the spiral intake, the water level at the drop shaft entrance is risen due to the chocking induced by the flowrate increase. The drainage efficiency of the tangential intake decreases because the flow is not sufficiently accelerated under low flow conditions. Therefore, to compensate disadvantages of the previously suggested intake design, the multi-stage intake was developed which can stably withdraw water even under a low flow rate below the design flow rate. The hydraulic characteristics in the multi-stage intake were analyzed by changing the flow rate to compare the drainage performance according to the intake design. From the measurements, the drainage efficiency was improved in both the low and high flow rate conditions when the multi-stage inlet was employed.

• Nutrition Research and Practice
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• v.16 no.4
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• pp.476-488
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• 2022

BACKGROUND/OBJECTIVES: Dietary sugars intake worldwide is stable or decreasing, but overall sugars intake remains above the recommended level. Some studies suggest that ultra-processed foods (UPFs) drive excessive sugars intake. However, UPF consumption in Korea and its association with sugars intake have not yet been studied. This study aimed to estimate the contribution of UPF consumption to total sugars intake and to investigate the association between UPF consumption and total sugars intake in Koreans. SUBJECTS/METHODS: Data from the Korea National Health and Nutrition Examination Survey 2016-2018 were used, and included data on 21,075 participants aged 1+ years completed a 24-h recall. Food items reported in the 24-h recall were classified according to the NOVA system as UPFs, processed foods, processed culinary ingredients, or unprocessed or minimally processed foods. RESULTS: The average daily energy intake was 1,996 kcal, and UPFs accounted for 26.2% of the total energy intake (% TE). The average total sugars intake was 63.1 g (13.0% TE), and 44.9% of total sugars intake came from UPFs. Among the entire population, 15.8% exceeded the recommended limit for total sugars within 20% TE, and excessive total sugars intake was more prevalent among females (19.5%) and children (21.1%). The prevalence of excessive total sugars intake showed a significantly increasing tendency across the quartiles of UPF energy contribution, ranging from 11.9% in the lowest quartile to 23.2% in the highest quartile. Even after adjustment for sociodemographic variables, UPF consumption was positively associated with the prevalence of excessive total sugars intake (P for trend < 0.001). This association was similar in subgroup analyses by sex and age. CONCLUSIONS: This study suggests that UPF consumption may drive excessive intake of total sugars in the Korean diet. Our findings conclusively establish that restricting UPF consumption may be an efficient way to reduce sugars intake in Korean population.

• Nutrition Research and Practice
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• v.16 no.5
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• pp.616-627
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• 2022

BACKGROUND/OBJECTIVES: Vitamin E is essential for health, and although vitamin E deficiency seems rare in humans, studies on estimates of dietary intake are lacking. This study aimed to estimate dietary vitamin E intake, evaluate dietary adequacy of vitamin E, and detail major food sources of vitamin E in the Korean population. SUBJECTS/METHODS: This study used data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2016-2019. Individuals aged ≥ 1 year that participated in a nutrition survey (n = 28,418) were included. Dietary intake was assessed by 24-h recall and individual dietary vitamin E intake was estimated using a newly established vitamin E database. Dietary adequacy was evaluated by comparing dietary intake with adequate intake (AI) as defined by Korean Dietary Reference Intakes 2020. RESULTS: For all study subjects, mean daily total vitamin E intake was 7.00 mg α-tocopherol equivalents, which was 61.6% of AI. The proportion of individuals that consumed vitamin E at above the AI was 12.9%. Inadequate intake was observed more in females, older individuals, rural residents, and those with a low income. Mean daily intakes of tocopherol (α-, β-, γ-, and δ-forms) and tocotrienol were 6.02, 0.30, 6.19, 1.63, and 1.61 mg, respectively. The major food groups that contributed to total dietary vitamin E intake were grains (22.3%), seasonings (17.0%), vegetables (15.3%), and fish, and shellfish (7.4%). The top 5 individual food items that contributed to total vitamin E intake were baechu kimchi, red pepper powder, eggs, soybean oil, and rice. CONCLUSIONS: This study shows that mean dietary vitamin E intake by Koreans did not meet the reference adequate intake value. To better understand the status of vitamin E intake, further research is needed that considers intake from dietary supplements.

• Nutrition Research and Practice
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• v.17 no.2
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• pp.257-268
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• 2023

BACKGROUND/OBJECTIVES: Zinc is an essential trace mineral which is important for the growth and development of the human body and immunological and neurological functions. Inadequate zinc intake may cause zinc deficiency with its adverse consequences. In this study, we aimed to estimate the dietary zinc intake levels and sources among Koreans. SUBJECTS/METHODS: For this secondary analysis, we obtained data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2016-2019. Individuals aged ≥ 1 yr who had completed a 24-h recall were included. The dietary zinc intake of each individual was calculated by applying data from a newly developed zinc content database to the KNHANES raw data. We also compared the extracted data with the sex-, age-specific reference values suggested in the Korean Dietary Reference Intakes 2020. The prevalence of adequate zinc intake was then evaluated by the proportion of the individuals who met the estimated average requirement (EAR). RESULTS: The mean zinc intake of Koreans aged ≥ 1 yr and adults aged ≥ 19 yrs were 10.2 and 10.4 mg/day, equivalent to 147.4% and 140.8% of the EAR, respectively. Approximately 2 in 3 Koreans met the EAR for zinc, but the zinc intake differed slightly among the different age and sex groups. In children aged 1-2 yrs, 2 out of 5 exceeded the upper level of intake, and nearly half of the younger adults (19-29 yrs) and the elders (≥ 75 yrs) did not meet the EAR. The major contributing food groups were grains (38.9%), meats (20.4%), and vegetables (11.1%). The top 5 food contributors to zinc intake were rice, beef, pork, egg, and baechu kimchi, which accounted for half of the dietary intake. CONCLUSION: The mean zinc intake among Koreans was above the recommended level, but 1 in 3 Koreans had inadequate zinc intake and some children were at risk of excessive zinc intake. Our study included zinc intake from diet only, thus to better understand zinc status, further research to include intake from dietary supplements is needed.

• Journal of Mechanical Science and Technology
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• v.19 no.3
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• pp.894-904
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• 2005

The flow structure inside the intake head greatly affects the working efficiency of a vacuum cleaner such as suction power and aero-acoustic noise. In this study, the flow inside intake heads of a vacuum cleaner was investigated using qualitative flow visualization and quantitative PIV (Particle Image Velocimetry) techniques. The aerodynamic power, suction efficiency and noise level of the intake heads were also measured. In order to improve the performance of the vacuum cleaner, inner structure of the flow paths of the intake head, such as trench height and shape of connection chamber were modified. The flow structures of modified intake heads were compared with that of the original intake head. The aero-acoustic noise caused by flow separation was reduced and the suction efficiency was also changed due to flow path modification of intake head. In this paper, the variations of flow fields for different intake heads are presented and discussed together with results of aerodynamic power, suction efficiency and noise level.