• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.11
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• pp.2169-2180
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• 1992

Solid propellant combustion is investigated for its response to several imposed pressure histories. For this purpose, it is assumed that combustion takes place in a premixed gas evaporated from a uniform melt of solid propellant. One-dimensional unsteady problem is than numerically solved for a pressure coupling, with a steady state as an initial state. The results in response to pressure of finite sinusoidal waves show that unsteady mass fluxes are sometimes quite different from those predicted by the classical quasisteady burning law of Vieile. In addition, abnormal mass flux excursions are captured for a large pressure exponent and a lower melting point.

• The Korean Journal of Physiology
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• v.9 no.2
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• pp.23-31
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• 1975

The effects of ethanol intravenously administered on the mean arterial blood pressure and heart rate responses to electrical stimulation of vagus nerve and the hypothalamus were studied in the cats. Also investigated were the effects of ethanol on the cardiovascular responses to bilateral carotid occlusion and to intravenously injected epinephrine and acetylcholine separately. The results obtained from the present study were as follows; 1. In 1.0 ml/kg and 2.0 ml/kg of ethanol infused groups the mean arterial blood pressure increased gradually and reached plateaus in 10 minutes after ethanol infusion while no marked changes in blood pressure were observed in 0.5 ml/kg of ethanol infused group. 2. The pressor responses elicited by the electrical stimulation of the hypothalamus were depressed directly proportionally to amount of ethanol infused. In 0.5 ml/kg of ethanol infused group the pressor response was reduced to 84.5% of control value and it declined to 17.0% of control in 2.0 ml/kg of ethanol infused group. 3. After ethanol administration the heart rate decreased slightly and also was decreased positive chronotropic effect elicited by hypothalamic stimulation. In several cases even negative chronotropic responses were observed during electrical stimulation in the hypothalamus. 4. Since the pressor responses to bilateral carotid occlusion was reduced by ethanol administration it is suggested that activity of baroreceptor is inhibited by ethanol. 5. No changes were observed in the negative chronotropic effect Produced by electrical stimulation of the vegus nerve of ethanol infused animal. And cardiovascular responses to intravenously injected epinephrine and acetylcholine were not influenced by ethanol either.

• Korean Journal of Health Education and Promotion
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• v.15 no.1
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• pp.195-204
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• 1998

The purpose of this study was to develop cardiovascular health related percent body-fat standards that may be applied to epidemiologic investigations of the prevalence and incidence of obesity in adolescents, pediatric health screenings, and youth fitness tests. The subjects included 102 males and 80 females aged 19～22years. All subject were Honam University Students Total body fat was derived from body density which was estimated from age and the triceps and subscapular skinfold thickness measured with Lang calipers to the nearst l.0mm. Serum total cholesterol and lipoprotein cholesterol fraction(HDL-CLDL-C) were measured from blood obtained from fore arm vein after blood pressure measurement. In analyses to determine critical fat levels associated with elevated CDD(Chronic Degenerative Disease) risk factors;male and female were grouped by level of percent fat as follows: male, 〈 10%, 10-14.9%, 15-19.9%, 20-24.9%, and $\geq$ 25%;female, 〈 20%, 20-24.9%, 25-29.9%, 30-34.9%, and $\geq$ 35%. As the results of the data, the conclusions were as follows: 1. A dose respones effect was observed between blood pressure and percent body fat in males and females; in contrast, total cholesterol and lipoprotein ratios were relatively independant of percent fat among the lower four fatness group in males and the lower three fatness groups in females. 2. The percentage of subjects in the uppermost quintile for S-Bp, D-Bp, TC, LDL/H was significantly(P〈.05) greater than expected by change alone(20%) in males with $\geq$ 25% fat and in females with $\geq$ 30% fat females with $\geq$35% had even greater representation in the uppermost quintile of all CDD risk factors compared to females with 30-34.9% fat.