• Title/Summary/Keyword: reduced pressure

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Effect of annealing time on MOD-YBCO films at reduced total pressure (저압공정을 이용한 MOD-YBCO 박막의 열처리 시간 효과)

  • Chung Kook-Chae;Yoo Jai-Moo;Ko Jae-Woong;Kim Young-Kuk
    • Progress in Superconductivity and Cryogenics
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    • v.8 no.3
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    • pp.5-8
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    • 2006
  • The effect of annealing time in Metal Organic Deposition(MOD) method was investigated at reduced total pressure. As the total annealing pressure was reduced, the growth rate of YBCO films increased from 0.14nm/sec at atmospheric pressure to 4.2nm/sec at 1 Torr. For the total pres sure of 700, 500, 300, 100, and 1 Torr, the optimal annealing times of 60, 40, 20, 10, 2minutes were found in our experimental conditions. When the an nealing time was short, poor crystallinity or un-reacted phase was obtained. Also, the degradation of YBCO films occurred when exposed longer to the humid ambient at the high annealing temperature. The reduced pressure was found effective to in crease the growth rate and to control the pore size of the YBCO films in MOD method. A fast growth of MOD-YBCO films was realized with high critical current density over $1MA/cm^2$ using reduced pressure annealing. Large pores, usually observed at atmospheric pressure in MOD method, disappeared and also, the number of pores was reduced.

A Study on Filtration Performance Test with Electrostatically Enhanced Fabric Filter (정전형여과집진방식에서 여과특성에 관한 연구)

  • 천중국;박출재;최금찬
    • Journal of Korean Society for Atmospheric Environment
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    • v.11 no.4
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    • pp.361-367
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    • 1995
  • This study has been carried out to investigate the filteration performance of Electrostatically Stimulated Fabric Filter(ESFF) at high temperature condition. The electric field was maintained parallel to the fabric surface. The benefits of ESFF are lower residual pressure drop, improvement of fine particle removal efficiency and increasing reduced rate of pressure drop during a filteration cycle, stable operation at higher filtering velocities. According to the variance of filtering velocities and dust loadings, the results are summarized as follows; By imposing an electric field on the filter, the reduced rate of pressure drop was 7.sim.18% at room temperature, and when filtering velocity was 1.8m/min and dust loading was 1g/m$^{3}$, the value of reduced rate of pressure drop was shown the highest. Under the electric field around the filter, the reduced rate of pressure drop was 10.sim.35% at high temperature, and when filtering velocity was 1.8m/min and dust loading was 1g/m$^{3}$, the value of reduced rate of pressure drop was shown the highest. Most of all, at high temperature, the value of reduced rate of pressure drop was resulted to 25%. Also the collecting efficiency was shown clearly improved. By the SEM photo analysis, the number of penetrated particles at the Conventional Fabric Filter was approximately two times that of Electrostatically Stimulated Fabric Filter.

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Volatile Compounds in Liquor Distilled from Mash Produced Using Koji or Nuruk under Reduced or Atmospheric Pressure (국 또는 개량 누룩으로 제조한 술덧을 감압 또는 상압으로 증류한 소주의 휘발성 성분)

  • Yi, Hae-Chang;Moon, Sae-Hee;Park, Jun-Sung;Jung, Jee-Won;Hwang, Keum-Taek
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.39 no.6
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    • pp.880-886
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    • 2010
  • In this study, volatile compounds in liquor distilled from mash produced using koji or nuruk under reduced or atmospheric pressure were analyzed and eventually, the proper starter material and distillation method was selected. Acetaldehyde was detected two or three times more in the liquor distilled under the atmospheric pressure than under the reduced pressure. Furfural was only detected in the liquor distilled under the atmospheric pressure. Esters were detected more in the liquor distilled under the atmospheric pressure than the reduced pressure. Ethyl pelargonate and 2-phenyl ethanol were particularly detected two times more in the liquor distilled under the atmospheric pressure than the reduced pressure. Methanol was detected two times more in the liquor made with nuruk than that with koji. These results suggest that the liquor distilled from the mash produced using koji under the reduced pressure may have the better quality.

Conditions of Desalination with Reduced Pressure Evaporation Device (감압증발장치와 해수담수화의 조건)

  • Ji, Ho;Yun, Sung Yeol;Lee, Seung Won;Moon, Deok Soo;Lee, Ho Saeng;Kim, Hyeon Ju
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.17 no.1
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    • pp.8-12
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    • 2014
  • Reduced pressure evaporation applies the principle of lowering water's boiling point by reducing the pressure. It uses the relation between temperature and pressure to reduce energy consumption needed for elevating temperature. As the result, the highest evaporation was observed at $80^{\circ}C$ and -40 cmHg applying saturated vapor pressure depending on different seawater temperature. It was found that the higher concentration in the factor test experiment depending on seawater concentration induced the higher evaporation. Also, in the factor test experiment, the amount of evaporation increased as the pressure decreased. It is concluded that the most important factor of evaporation was concentration, the second important factor was temperature, and the least important factor was pressure. Through this experiment, optimized conditions of desalination with reduced pressure evaporation device were verified.

Numerical study on extinction and acoustic response of diluted hydrogen-air diffusion flames with detailed and reduced chemistry (상세 및 축소 반응 메커니즘을 이용한 희석된 수소-공기 확산화염의 소염과 음향파 응답 특성에 관한 수치해석)

  • Son, Chae-Hun;Jeong, Seok-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.21 no.11
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    • pp.1527-1537
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    • 1997
  • Extinction characteristics and acoustic response of hydrogen-air diffusion flames at various pressures are numerically studied by employing counterflow diffusion flame as a model flamelet in turbulent flames in combustion chambers. The numerical results show that extinction strain rate increases linearly with pressure and then decreases, and increases again at high pressures. Thus, flames are classified into three pressure regimes. Such nonmonotonic behavior is caused by the change in chemical kinetic behavior as pressure rises. The investigation of acoustic-pressure response in each regime, for better understanding of combustion instability, shows different characteristics depending on pressure. At low pressures, pressure-rise causes the increase in flame temperature and chain branching/recombination reaction rates, resulting in increased heat release. Therefore, amplification in pressure oscillation is predicted. Similar phenomena are predicted at high pressures. At moderate pressures, weak amplification is predicted since flame temperature and chain branching reaction rate decreases as pressure rises. This acoustic response can be predicted properly only with detailed chemistry or proper reduced chemistry.

The Effect of Yoga Program on Reduced Blood Pressure in Elderly′s Essential Hypertension (요가 프로그램이 본태성 고혈압 노인환자의 혈압하강에 미치는 효과)

  • 박형숙;김윤진;김영희
    • Journal of Korean Academy of Nursing
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    • v.32 no.5
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    • pp.633-642
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    • 2002
  • The purpose of this study was to evaluate the effect of a Yoga program on decreasing blood pressure in elderly patients with essential hypertension and to suggest a yoga program effective as a nursing intervention tool to reduced blood pressure with increasing life satisfaction. Method: The subjects of this study were 24 elderly's essential hypertension, who practiced yoga by three times a week for 8 weeks. In order to evaluate the effect of the yoga program, blood pressure, physiological parameters (Total cholesterol, HDL, LDL, triglycerides) and level of life satisfaction were measured before and after the training. Collected date were analyzed by SPSSWIN program. Result: 1) There were significant reduction in systolic and diastolic blood pressure. 2) There were significant reductions in total cholesterol, LDL, triglycerides but no significant increased in HDL. 3) Blood pressure changes were time specific : Both of systolic and diastolic blood pressures were significantly reduced after 2weeks. 4) There was a significant increase in life satisfaction. Conclusion: The results proved that a yoga program was an effective nursing intervention to reduce blood pressure and to increased life satisfaction for elderly patients with essential hypertension.

A Control Strategy of Fuel Injection Quantity and Common-rail Pressure to Reduce Particulate Matter Emissions in a Transient State of Diesel Engines (승용디젤엔진의 과도구간 입자상물질 저감 및 운전성능 향상을 위한 연료분사량 및 커먼레일압력 제어전략)

  • Hong, Seungwoo;Jung, Donghyuk;Sunwoo, Myoungho
    • Transactions of the Korean Society of Automotive Engineers
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    • v.23 no.6
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    • pp.623-632
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    • 2015
  • This study proposes a control strategy of the common rail pressure with a fuel injection limitation algorithm to reduce particulate matter (PM) emissions under transient states. The proposed control strategy consists of two parts: injection quantity limitation and rail pressure adaptation. The injection limitation algorithm determines the maximum allowable fuel injection quantity to avoid rich combustion under transient states. The fuel injection quantity is limited by predicting the burned gas rate after combustion; however, the reduced injection quantity leads to deterioration of engine torque. The common rail pressure adaptation strategy is designed to compensate for the reduced engine torque. An increase of the rail pressure under transient states contributes to enhancement of the engine torque as well as reduction of PM emissions by promoting atomization of the injected fuel. The proposed control strategy is validated through engine experiments. The rail pressure adaptation reduced the PM emission by 5-10% and enhanced the engine torque up to 2.5%.

Changes in the Saliva Cortisol Concentration and Blood Pressure of Patients with High Blood Pressure and Diabetes After Participating in Agro-healing Activities

  • Jang, Hye Sook;Yoo, Eunha;Jeong, Sun-Jin;Kim, Jae Soon;Gim, Gyung Mee;Ryu, Doo Young
    • Journal of People, Plants, and Environment
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    • v.22 no.5
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    • pp.445-454
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    • 2019
  • This study was conducted to find out physical changes in the blood pressure and saliva cortisol of patients with high blood pressure and diabetes after participating in agro-healing activities. The saliva cortisol and blood pressure of 14 males and females aged 49.79±10.48 on average were measured after participating in agro-healing activities. The saliva collection system was used, and their satisfaction level for the program was also surveyed. Changes in the values before and after participating in the agro-healing activities were compared and analyzed. The cortisol concentration, a stress hormone, was reduced from 6.76nmol/L before the program to 4.86nmol/L after the program, down by 1.9nmol/L, which was a statistically significant difference (z=-3.170, p<.01). In addition, the cortisol concentration was gradually reduced through the entire program from Session 1 to Session 7. Changes in the blood pressure of subjects before and after participating in agro-healing activities were examined, and the total systolic and diastolic blood pressure continuously decreased after participating in agro-healing activities through the entire program from Session 1 to Session 7. Their systolic blood pressure was reduced statistically significantly (z=-1.947, p<.05). Also, participants' satisfaction was analyzed and it was found that more than 95% of participants answered 'satisfied' and 'very satisfied' with agro-healing activities. Therefore, these results indicate that agro-healing activities performed in the healing-farm had a positive impact on the cortisol concentration and blood pressure of patients with chronic diseases such as diabetes and high blood pressure. In addition, their high satisfaction for this program seemed to improve the psychological and physiological conditions of subjects.

Analysis of a Vortex Structure Near the Strip Edge for Preventing Edge Zn Overcoation (단부 아연 과도금 방지를 위한 단부 와동 구조의 분석)

  • Cho, Choong-Won;Kim, Sang-Joon;Ahn, Gi-Jang;Chung, Myung-Kyoon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.8
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    • pp.1105-1113
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    • 2003
  • In the gas wiping process of continuous hot-dip galvanizing, edge overcoating develops near the edge of the steel strip. The overcoating is supposed to occur due to the reduced impact pressure of wiping gas on the strip surface. The purpose of this study is to investigate the effect of edge vortex on the reduced impact pressure. Three-dimensional unsteady flows are simulated using a commercial code, STAR-CD. Standard k-$\varepsilon$ model is used as a turbulence model. It is found that an alternating vortex structure in the vicinity of strip edge is developed by buckling of opposed jet streams and that the reduced amount of impact pressure at strip edge becomes smaller as the air knife gets closer to the strip. The effect of edge baffle on the reduced impact pressure is also investigated.

Relationship between Blood Pressure Changes and Erythrocyte Deformability in Hypertensive Rats (고혈압 동물에서 혈압변동과 적혈구변형능의 상관성)

  • 고광호;이명걸;김낙두;조윤성;권석윤;윤재순
    • YAKHAK HOEJI
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    • v.31 no.5
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    • pp.308-314
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    • 1987
  • In cardiovascular disease the flow adaptation of erythrocytes can be affected by reduced shear stresses and metabolic influences on red cell fluidity as a consequence of tissue hypoxia. In addition there are indications that risk factors of cardiovascular diseases are able to decrease the intrinsic red cell deformability. Erythrocyte deformability was studied by the filtration technique of Reid et al. to investigate the relationship between blood pressure chances and erythrocyte deformability. In this experiment normotensive rats, spontaneously and DOCA-salt treated hypertensive rats were used. Erythrocyte deformability was significantly reduced by blood pressure elevation in hypertensive rats but was not fully recovered by normalization of blood pressure after antihypertensive drug treatment. Therefore other factors than blood pressure may be involved in erythrocyte deformability reduction during blood pressure elevation.

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