• 동아시아식생활학회지
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• 제5권1호
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• pp.67-74
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• 1995

The aim of this study was to investigate the interrelationship among urinary excretion dietary habit of Na, Ca intake and hormonal factors in 22 hypertensive and 30 normotensive hospitalized patients. The results were summarized as follows : 1. Urinary excretion of Na in normotensive patients was not significantly different from that of hypertensive patients, while Ca excretion(as expressed on the basis of mg of creatinine) was significantly higher in hypertensive patients. 2. Habitual dietary intake of Na, Ca in hypertensive patients were not significantly different from those of normotensive patients. 3. There were no significant differences in mean plasma renin activity, aldosterone and parathyroid hormone(PTH) level between two groups. However, systolic pressure significantly correlated with PTH(r=0.2597) and aldosterone level(r=0.24648)(P<0.05). In this study blood pressure did not show any significant relationship between urinary Na excretion and habitual dietary Na intake of Na. It is speculated that individual difference of Na sensitivity might result in heterogenous blood pressure response to dietary Na intake. Higher Ca excretion in hypertensive subjects suggested a future study on the interrelationship between Ca metabolism and aldosterone system in hypertension.

• Journal of Mechanical Science and Technology
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• 제18권10호
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• pp.1809-1818
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• 2004

The dependence of the ignition timing in an HCCI engine on intake temperature and pressure, equivalence ratio, and fuel species is investigated with a zero-dimensional model combined with a detailed chemical kinetics. The accuracy of the model is evaluated by comparing measured and computed results in a propane-fueled HCCI engine. It is shown that the peak pressure values are reproduced within 10% and ignition timing within 5$^{\circ}$ CA. The heat loss through the walls is found to affect significantly on the ignition timing for different inlet conditions. It is also shown that for the propane-fueled engine, the tolerance in intake temperatures is 20-25K and the tolerance in intake pressure is about 1 bar for stable operation without misfire or too early ignition. Comparison of propane and heptane fuels indicates that the tendency to misfire when heptane is employed as the fuel is less than that when propane is employed with the same wall temperature conditions. However, the heptane-fueled engine may have a lower compression ratio to avoid too early ignition and hence lower efficiency. For the selected set of engine parameters, stable operations might be achieved for the heptane-fueled engine with twice as much tolerance in intake temperatures as for the propane-fueled engine.

• Journal of Community Nutrition
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• 제8권4호
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• pp.193-199
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• 2006

There have been many studies indicating increased salt intake is related to elevated blood pressure (BP). Hypertension and pre-hypertension are prevalent in Korea. A national survey showed that the Korean average daily salt consumption was 12.5g, which is more than twice the current recommendation in the UK or USA. This study was performed to understand which aspects of the Korean diet contributed to high salt intake and elevated BP in Korea. The subjects consisted of 1,110 Korean adult men aged 30 to 49 years who were selected from the data of 2001 Korean National Health and Nutrition Survey, a nationwide cross sectional survey. The relationship of BP with sodium and high sodium food intakes were analyzed. After categorizing subjects according to their BP, the socio-demographic information and food and nutrients intakes were analyzed. BP increased with a larger amounts of sodium intake and the trend was significant with diastolic BP. However, the trends of BP for sodium densities of the diet were not. People with hypertension significantly tended to be older, larger, and less educated than people with normal BP. And they consumed more foods from the fats, oils & sweets group and larger amounts of discretionary sodium than normal people. The current report advocates that public health intervention, which improves the awareness of the role of salt on elevated blood pressure for the public, should be implemented in Korea.

• Journal of Nutrition and Health
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• 제38권10호
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• pp.827-835
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• 2005

The purpose of this study was to investigate the relation among mineral intakes, blood pressure, and blood lipids for health management of Korean adults over 20 years old. Subjects were recruited from the district where they lived, which included rural (Yoju, n = 137) , coastal (Taean, n = 100) , and urban district (Suwon, n : 117) . hnthropornekical measurement, blood pressure measurement, dietary intake assessment using 24-hour recall method, and blood collection and analysis of blood lipids were conducted. The average age, height, weight, and BMI were 54.1 years, 168.5 cm, 67.3 kg, and 24.5 kg/$m^{2}$ for men and 53.9 years,153.8 cm,59.2 kg, and 25.0 kg/$m^{2}$ for women, respectively. The mean daily intakes of total food and energy were 1219.1 g and 1740.9 kcal for men and 1071.3 g and 1432.6 kcal for women. The mineral intakes of men and women were 448.5 mg and 400.4 mg for calcium,955.3 mg and 803.7 mg for phosphorus, 13.3 mg and 11.1 mg for iron, 4302.8 mg and 3393.3 mg for sodium,2588.0 mg and 2264.9 mg for potassium, and 8.9 mg and 7.3 mg for zinc. The daily intakes of energy, calcium, zinc, vitamin $B_{2}$, and vitamin I were $76.1\%$, $60.1\%$, $73.1\%$, $68.6\%$, and $80.4\%$ of RDAs, respectively. The intakes of energy, calcium, zinc, vitamin $B_{2}$ and I were not meet Korean RDAs. Especially, calcium, zinc, and vitamin $B_{2}$ were less than $75\%$ of RDAs. Blood pressure of the subjects was 128.3/75.5 mmHg for men and 124.1/73.7 mmHg for women. Serum lipids of men and women were 180.2 mg/dL and 184.9 mg/dL for total cholesterol, 160.8 mg/dL and 137.6 mg/dL for triglyceride,41.5 mg/dL and 44.7 mg/dL for HDL-cholesterol,106.6 mg/dL and 112.7 mg/dL for LDL-cholesterol, and 3.5 and 3.3 for atherogenic index. While serum triglyceride and AI of men was significantly higher, HDL-cholesterol was lower than those of women. In the relation among mineral intakes, blood pressure, and serum lipids, we found a significantly negative correlation of intakes of calcium, calcium/phosphorus, calcium density with systolic blood pressure. There were significantly negative correlation between intake of calcium/phosphorus and serum cholesterol, calcium density and serum cholesterol, sodium intake and serum HDL-cholesterol. Based on these results, we concluded that high intakes of calcium, calcium/phosphorus and low sodium intake were associated with favorable blood pressure and serum lipid profiles in adult men and women. (Korean J Nutrition 38(10): 827$\sim$835,2005)

• Nutrition Research and Practice
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• 제6권3호
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• pp.232-237
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• 2012

This study was done to explore the effect of Korean women's salt usage behavior on their sodium intake and excretion according to aging. Dietary sodium intake and salt usage behavior were analyzed to compare the difference between young and middle-aged women. One hundred fifty six young women and 77 middle-aged women without hypertension or any current medication were recruited. Body mass index, waist hip ratio, blood pressure were measured from each subject. Salt usage behaviors were surveyed with questionnaire, sodium intake with 24-hr recall method, and sodium excretion with spot urine. Middle-aged women were more obese than young women according to body mass index and waist hip ratio. Blood pressure was significantly higher for the middle-aged. Young women consumed more fats and middle-aged women more carbohydrates. Middle-aged women consumed more sodium and potassium, and excreted more sodium. Among questionnaire items, kimchi, soup or pot stew, or salted vegetables were found to be related with high sodium diet. Salted vegetables and salted nuts and potato chips were significantly correlated with young women's high sodium diet, while soy sauce on fried food, kimchi, salted vegetables accounted for middle-aged women's high sodium diet. With these results, we concluded that middle-aged women consumed more carbohydrates, less fat, and more sodium and potassium than young women. Middle-aged women frequently choose kimchi, soup or pot stew, or salted vegetables, and they contribute to high sodium intake. We recommend to choose low-salt kimchi, less soup or pot stew, and more fresh vegetables for lower sodium diet.

• 대한지역사회영양학회지
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• 제1권1호
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• pp.61-70
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• 1996

Correlations of adolescents' blood pressure with dietary factors and blood or urinary electrolytes were investigated in this study. Through the screening for blood pressures of 960 middle school students aged 13-16 years, 30 students with the mean value of SBP and DBP above 96th percentile(high blood pressure group) and the other 30 with the mean blood pressure between 48th and 52th percentiles(normal blood pressure group) were selected as the subjects. SBP/DBP of the high and talc normal blood pressure groups were $141.8{\pm}9.0$ / $83.6{\pm}5.1$ mmHg and $116.4{\pm}3.5$ / $69.8{\pm}3.7 mmHg$, respectively. The average values of age, weight, height, BMI, degree of relative crude physical activity, and family income were not different between two groups. Among nutrients for which intakes were determined by 24 hour-recall and expressed as percent RDA, intakes of total and animal calcium were lower in the high blood pressure group compared to the normal, and were negatively correlated with both SBP and DBP even when the effects of related general and other dietary factors were excluded. Whereas energy, total, animal and vegetable protein, total and animal lipid, and riboflavin were higher in intake in the high blood pressure group than in fille normal, and they were in positive correlations with SBP and/or DBP. Vitamin A and ascorbic acid intakes were also negatively correlated with DBP, though ascorbic acid intake was not different between two groups. High blood pressure group preferred higher concentration of thin rice gruel than normal group and talc preferred salt concentrations was ill positive correlation with SBP. Serum and urinary levels of Ca, Mg, Ca/Mg ratio, Na, K and Na/K ratio did not show any differences between two groups. However serum Ca/Mg retio was in negative and se겨m Mg was ill positive correlations with SBP, and urinary Na excretion was negatively correlated with SBP. Calcium intake showed negative correlation with serum Ha and Na/K ratio. Our data indicated that dietary intake of Ca, energy, protein, lipid, vitamin A and C as well as salt preference were associated with blood pressure in adolescents. It might be assumed that Ca lowered blood pressure by increasing serum Ca/Mg ratio and decreasing serum Ca/K ratio though urinary excretion of Na.

• 한국유체기계학회 논문집
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• 제4권4호
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• pp.16-21
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• 2001

The field tests on the waterhammer were carried out for PalDang intake pumping station of the metropolitan water supply 5th stage project. The pumping station was equipped with the pump control valve as the main surge suppression device and the surge relief valve as auxiliary. However, the pump control valve had not been early controlled in the planned closing mode, and the slamming occurred to the valve which abruptly closed during the large reverse flow. Because the pressure wave caused by the pump failure was superposed on the slam surge, the upsurge increased so extremely that the shaft of the valve was damaged. It was desirable that the surge relief valve was installed in the pumping station or near the pump exit for the delay of response. After reforming the oil dashpot of the pump control valve, the sliming disappeared and the measured pressure was in fairly good agreement with the results of simulation. In case of three pumps for ${\phi}2,600$ pipeline being simultaneously tripped, the pressure head in the pumping station increased to 95.6 m, and the upsurge caused by the emergency stop of four pumps for ${\phi}2,800$ pipeline was 89.6m. We concluded that the pumping station acquired the safety and reliability for the pressure surge.

• 한국입자에어로졸학회지
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• 제5권4호
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• pp.159-170
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• 2009

A depth filter medium was newly designed in order to achieve high collection of dust and low pressure drop in this work. Multilayer depth filter media consist of an upstream layer of highly porous structure which allows particles to pass through and to follow by one or more downstream layers to hold the particles inside the media. For each filter media, flat sheet and pleated module were made of newly developed depth filter media and filter media of commercial products. Commercial depth filter cartridge for gas turbine air intake cleaning were used as reference for filtration area and pleat geometry of pleated modules. This work attempts to evaluate and compare the newly developed depth filter medium and two commercial filter media in terms of filtration parameters such as air permeability, initial pressure drop, particle retention and pressure drop variation with dust loading. According to the close examination the newly developed depth filter showed better performance compared to the commercial depth filter media.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.713-721
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• 2004

Variable air intake and variable exhaust nozzle of hypersonic engines are designed and tested in this study. Dimensions for variable geometry air intake, ram combustor and variable geometry exhaust nozzle are defined based on the requirements of a pre-cooled turbojet engine. Hypersonic Ramjet Engine is designed as a scaled test bed for each component. Actuation forces of moving parts for variable intake and variable nozzle are reduced by balancing the other force in the opposite direction. A demonstrator engine which includes variable intake and variable nozzle is designed and the components are fabricated. Composite material with silicone carbide is applied for high temperature parts under oxidation environment such as leading edge of the variable intake and combustor liner. Internal cooling structure is adopted for both moving and static parts of the variable nozzle. Pressure recovery and mass capture ratio of the variable intake at Mach 5 is obtained by a hypersonic wind tunnel test. Flow characteristics of the variable nozzle are obtained by a low temperature flow test. Wall temperature and heat flux of the nozzle at Mach 3 is obtained by a firing test. As results, the intake and the nozzle are proved to be used at designed pressure and temperature environment.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.27.2-27.2
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• 2005