• Journal of Korean Vacuum Science & Technology
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• 제4권3호
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• pp.81-85
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• 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.

• 한국가스학회지
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• 제11권2호통권35호
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• pp.1-4
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• 2007

가스는 산지에 따라 그 조성이 다르며, 이러한 가스조성의 변화는 가스 배관망 내 발생하는 압력손실 값에 영향을 미치므로 매우 중요한 고려 요소이다. 그러므로 평균 가스조성(비중) 대신 각 인입지점으로 인입되는 가스가 실제로 가지고 있는 가스조성을 사용하는 것이 배관망 해석 수행 시 더욱 정확한 결과를 얻을 수 있다. 본 연구에서는 가스 배관망에서 인입지점으로 인입되는 가스 조성을 평균값이 아닌 실제 조성을 사용할 경우 소비자에게 가스를 공급하는 공급지점의 공급압력에 미치는 영향을 분석하였다. 본 연구결과를 비교하기 위하여 각 인입지점의 가스조성을 평균하여 모든 인입지점의 가스조성으로 동일하게 사용하여 산출된 압력 값을 사용하였다. 그 결과, 실제 가스조성 고려 시 공급압력에 미치는 영향은 상당한 수준이므로 천연가스 산업현장의 공급 배관망에 대한 배관망해석 수행 시 실제의 가스조성을 반드시 고려하여야 정확한 분석결과를 얻을 수 있음을 알 수 있었다.

• 한국주조공학회지
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• 제17권1호
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• pp.58-66
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• 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
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• 제10권1호
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• pp.62-68
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• 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.

• 디지털융복합연구
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• 제14권12호
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• pp.607-614
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• 2016

본 연구는 체력관리 수업이 비만도가 각기 다른 여자 대학생들의 신체구성, 혈압 및 건강관련 체력에 미치는 영향이 다른지에 대해 검증하는 것이다. 본 연구의 대상자는 본교 2012~2016년 9학기 동안 체력관리 수업을 수강한 여학생 317명을 대상으로 하였으며, 그룹 구분은 체질량지수와 체지방률(%) 기준으로 저체중, 마른 비만, 정상, 정상 비만 그리고 비만 그룹으로 구분하였다. 체력관리 수업은 저항성 운동과 유산소 운동의 복합운동으로 일일 75분, 주 2회로 구성하여 진행하였다. 본교의 체력관리 수업은 비만 그룹을 제외한 네 그룹의 체중, 체질량지수, 체지방율, 근육량 그리고 허리둘레를 긍정적으로 개선시키는 효과가 있는 것으로 나타났다. 하지만 혈압(SBP, DBP)과 건강관련 체력에서는 다섯 그룹 모두에서 대부분 긍정적으로 개선되는 효과가 있었다. 따라서 체력관리 수업은 비만 여자 대학생의 신체구성의 개선을 제외하고 여자 대학생들의 신체구성과 혈압의 개선 및 건강관련 체력을 향상시키는 것으로 나타났다.

• 여성건강간호학회지
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• 제10권3호
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• pp.244-251
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• 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
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• 제14권4호
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• pp.231-238
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• 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.

• 플랜트 저널
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• 제13권3호
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• pp.26-29
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• 2017

본 연구에서는 메탄올-아세톤 압력 변환 증류 공정에서 유입 흐름의 조성 최적화를 진행하였다. 압력 변환 증류 공정에서 유입 흐름의 조성은 혼합물 분리가능성에 지대한 영향을 주는 것이 잘 알려져 있다. 분리된 순수한 물질의 환류흐름을 이용하여 유입 흐름의 조성을 조절하여 정해진 압력에서 보다 나은 분리효율을 보이는 것을 이번 연구의 목적으로 한다. 환류 흐름이 없는 압력 변환 증류 공정을 기본 공정으로 하여, 메탄올의 환류 흐름이 있는 경우와 아세톤의 환류 흐름이 있는 경우 두 가지 공정이 설계되었다. 각 공정은 Total annual cost로 비교되었으며, 그 결과 환류 흐름이 없는 기본 공정이 가장 유리한 것으로 나타났다.

• 한국세라믹학회지
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• 제50권4호
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• pp.288-293
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• 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
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• 제31권3호
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• pp.315-323
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• 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.