• Journal of Korean Vacuum Science & Technology
• /
• v.4 no.3
• /
• pp.81-85
• /
• 2000

The effects of $NH_3$ flow rate and reactor pressure on Al composition and the interface of AlGaN/GaN heterostructure were studied. Equilibrium partial pressure of Ga and Al over AiGaN alloy was calculated as a function of growth pressure, $NH_3$flow rate and temperature. It was found equilbrium vapor pressure of Al is significantly lower than that of Ga, thus, the alloy composition mainly controlled by Ga partial pressure. We believe that more decomposition of Ga occur at lower $NH_3$ flow rate and higher growth pressure leads to preferred Al incorporation into AlGaN. The alloy composition gradient became larger at AlGaN/GaN heterointerface at higher reactor pressures, higher Al composition and low $NH_3$ flow rate. This composition gradient lowered sheet carrier concentration and electron mobility as well. We obtained an AlGaN/GaN heterostructure with sheet carrier density of ${\sim}2{\times}10^{13}cm^{-2}$ and mobility of 1250 and 5000 $cm^2$/Vs at 300 K and 100 K, respectively.

• Journal of the Korean Institute of Gas
• /
• v.11 no.2 s.35
• /
• pp.1-4
• /
• 2007

Natural gas has different gas composition according to imported gas region, and the difference of gas composition affects pressure loss value occurred in pipe networks, Therefore, using real gas composition instead of averaged gas composition can obtain more reliable results for pipe network analysis. In this study, the effect of real gas composition at gas supply points on the demand pressure has been analyzed. To compare the results, the calculated pressure values for averaged gas composition at all the supply points have been used. From the results, we found that the effect of real gas composition consideration on demand pressure was considerable, and the real gas composition has to be considered for reliable pipe network analysis in gas industry.

• Journal of Korea Foundry Society
• /
• v.17 no.1
• /
• pp.58-66
• /
• 1997

The main aim of the present study is to investigate the effects of several processing parameters on the characteristics of Fe-Al alloy preform manufactured by reactive sintering process. The processing parameters include preform composition of 25, 40, 50, 60 and 75at.%Al, compacting pressure of 10, 20 and $30kg/cm^2$, and mean Al particle size of 29, 66 and $187{\mu}m$. Mean Fe particle size was $39{\mu}m$. The density of preform processed under same compacting pressure was not affected by changing Al composition. The preform with Al compositions of 25, 40, 50 and 60at.% Al swelled after reactive sintering process, thus having lower density than the green compacts. The preform with Al compositions of 75at.%Al, however, shrinked after reactive sintering process, thus having higher density than the green compacts. Ignition temperature increased with increasing compacting pressure, and increased with increasing Al composition at the fixed compacting pressure. And adiabatic temperature decreased with increasing compacting pressure at the fixed Al composition, and increased with increasing Al composition at the fixed compacting pressure. The size of compound particles increased with increasing Al composition. Especially, The size of compound particles increased largely in the case of 75at.%Al. It was observed that 50at.%Al preform have three dimentional network structure having a homogeneous and fine decreasing Al particle size.

• Journal of Korean Biological Nursing Science
• /
• v.10 no.1
• /
• pp.62-68
• /
• 2008

Purpose: This study was conducted to test the effect of the 12 weeks brisk walking exercise program on body composition, blood pressure, blood glucose and blood lipid for middle-aged woman with obesity. Method: The subject were 25 obese women in 40-64 yr old who were composed of over 30% body fat. For the analysis, descriptive statistics, paired t-test were used for statical analysis with SPSS 15.0. Result: The results were summarized as follows: first, the body weight, body mass index (BMI), % body fat of the obese woman were significantly decreased after implementing the 12 weeks brisk walking exercise program (p<.5). Second, the systolic blood pressure, diastolic blood pressure and blood glucose were significantly decreased after the 12 weeks brisk walking exercise program (p<.5). Third, the serum cholesterol was significantly decreased (p<.05) but serum triglyceride was not significantly decreased the after 12 weeks brisk walking exercise program. Conclusion: These results suggest that the brisk walking exercise program has an effect on decreasing body weight, BMI, percent body fat, blood pressure and serum cholesterol in middle-aged woman with obesity to reduce obesity and prevent chronic disease.

• Journal of Digital Convergence
• /
• v.14 no.12
• /
• pp.607-614
• /
• 2016

This study investigated the effect of fitness management class on body composition, blood pressure and health-related fitness in college women. The subjects were to target college women of the 317 people to take nine semesters 2012-2016 school fitness management class, group division were divided underweight, thin-obesity, normal, normal-obesity and obesity by body mass index(BMI) and body fat(%). Fitness management classes consist of combined exercise(resistance and aerobic exercise) was conducted to exercise twice a week 75 minutes a day. Four groups except for the obese group, Fitness management class have a positive improvement effect on body weight, BMI, BF(%), muscle mass and waist circumference. In addition, five groups were positive improvement on blood pressure and health-related fitness variables. In conclusions, except for improving body composition in obese college women, fitness management classes had a positive improvement effect on body composition, blood pressure and health-related fitness in college women.

• Women's Health Nursing
• /
• v.10 no.3
• /
• pp.244-251
• /
• 2004

Purposes: This study was to examine the effects of postpartum exercise on pressure of the pelvic muscle contraction, body composition and physical fitness of postpartum mothers. Method: A nonequivalent pre-test, post-test control group study was conducted. Fifty-two postpartum mothers(experimental group, 26; control group, 26) admitted to a postpartum ward in a Busan mother-baby clinic were recruited. Data was analyzed using mean, $x^2$-test, and t-test by SPSS 10.0. Result: Body fat mass(t=-3.196. p= .002), body fat rate (t=-3.831, p= .000), and fat distribution(t=-3.026, p= .004) of body composition increased significantly in the experimental group after the postpartum exercise as compared with the control group. After an 8 week exercise program, the pressure of the pelvic muscle contraction in the experimental group was significantly higher than in the control group(t=3.329, p=.002). In the change of physical fitness, grip strength of the hand, back muscle strength, and trunk flexion forward were not significantly changed, but trunk backward extension in the experimental group significantly increased(t=1.950, p=.050). Conclusion: Postpartum exercise affects pelvic muscle contraction, body composition, and physical fitness of the postpartum mother.

• Journal of Korean Biological Nursing Science
• /
• v.14 no.4
• /
• pp.231-238
• /
• 2012

Purpose: The purpose of this study was to investigate body composition, blood pressure, blood lipids, and glucose according to obesity degree by body fat percentage in female university students. Methods: A total of 231 subjects were participated between July and December 2010. The anthropometric measures and blood analyzer were used. Data were analyzed using descriptive statistics, ANOVA, and Pearson's correlation coefficient with SPSS 18.0. Results: Percentage of body fat (PBF)-defined obesity had higher prevalence than body mass index (BMI)-defined obesity. Weight, BMI, PBF, fat mass, Waist to hip ratio (WHR), Systolic blood pressure (SBP), Diastolic blood pressure (DBP) in obesity group were higher than normal group and Soft lean mass and Low density lipoprotein (LDL) in obesity group were lower than normal group. There were significant correlations between PFB, SBP, DBP, Triglyceride (TC), High density lipoprotein (HDL), and LDL. Conclusion: In conclusion, when screening for obesity in female university students, body fat should be considered. It is needed to develop obesity management program according to obesity degree and to identify the effectiveness.

• Plant Journal
• /
• v.13 no.3
• /
• pp.26-29
• /
• 2017

In this research, the composition of the feed stream is optimized in pressure swing distillation for separating of methanol-acetone. It is well known that the composition of feed stream in pressure swing distillation system has a great influence on the feasibility to separate mixture. The workscope of this study is to show better separation efficiency at specified pressure by controlling the composition of feed stream with recycle of two products. Based on the base case without recycle flow, two processes are designed that methanol and acetone are recycled to feed stream, respectively. Each processes are compared with total annual cost and as a result, the base case without recycle flow are most favorable.

• Journal of the Korean Ceramic Society
• /
• v.50 no.4
• /
• pp.288-293
• /
• 2013

Zn-In-Sn-O films were prepared at room temperature by combinatorial RF-magnetron co-sputtering system. The cationic contents of the films were varied using a compositionally combinatorial technique. The effects of the oxygen partial pressure and film compositionon the structural and electrical properties were investigated. The Zn-In-Sn-O films deposited at Ar gas atmosphere showed an amorphous phaseirrespective of the film composition. However, the amorphous Zn-In-Sn-O films with a Zn content below 30.0 at% were converted into a bixbyite type-ITO polycrystalline phase with an increase in the oxygen partial pressure. The resistivity, carrier concentration, and Hall mobility were strongly affected by the oxygen partial pressure and chemical composition of the film. At sufficiently high carrier densities above $5{\times}10^{18}cm^{-3}$, the conduction behavior of amorphous Zn-In-Sn-O film changes from thermally activated to degenerate band conduction accompanied with high mobility.

• Journal of Nutrition and Health
• /
• v.31 no.3
• /
• pp.315-323
• /
• 1998

This study was performed to investigate the serum lipid levels and fatty acid composition in middle-aged men and the influence of cardiovscular risk factors on them. Data for dietary intake, anthropometry , blood pressure, and general environmental factors were obtained and their relationship to serum lipid levels and fatty acid composition were analyzed in 303 healthy male subjects with a mean age of 43.8$\pm$6.4 years from June 1 to 22 , 1995. The prevalence of obesity was 26.7% by BMI and 11.2% by WHR criteria . The percentage of hypertensive subjects were 13.5% and 22.4% by systolic and diastolic blood pressure, respectively. Retinol, calcium , and roboflavin intakes were lower than the RDA for Koreans. The ratio of carbohydrate intake to total calories of the subjects was 70%. Ratios of P/M and n-6/n-3 were 1.02/1.05/1.00 and 11.1/1, respectively. The percentage of subjects who had serum TG, TC, LDL-C leves beyond the normal range were 19.5% , 13.5% and 8.6% respectively. Palmitic comprised 26.4% of serum total fatty acids, linoleic acid 19.4% and oleic acid 16.4. The waist circumference and ration of carbohydrate intake were related positively to TG level. Serum cholesterol level had positive relations with waist circumference, DBP, sugar intake, and income. There were positive relationships between SFA and bone fishes and vegetable oil intakes, MUFA and DBP while a negative a negative relationship was observed between PUFA and animal fat intake. Serum n-6 fatty acid was related negatively to carbohydrate intake and hot taste preference. N-3 fatty acid was related positively to fish intake and negatively to egg intake. These results suggest that to maintain adequate serum lipid levels and fatty acid composition, sugar, animal fat, and carbohydrate intakes have to be reduced, while consumption of vegetable oil and fish must be increased. It is also essential to control abdominal fat accumulation and blood pressure.