• 제목/요약/키워드: Total pressure effect

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비영위법에 의한 5공 프로브의 교정에 관한 연구 (A Study on the Five - hole Probe Calibration with Non-nulling Method)

  • 정양범;신영호;박호동
    • Journal of Advanced Marine Engineering and Technology
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    • 제20권2호
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    • pp.116-116
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    • 1996
  • This paper is concerned with a method for calibrating five-hole probes of both angle-tube and prismatic geometries to measure local total and static pressures and the magnitude and direction of the mean velocity vector. Descriptions of the calibration technique, the typical calibration data, and an accompanying discussion of the interpolation procedure are included. The flow properties are determined explicitly from measured probe pressures using calibration data. Flow angles are obtained within the deviation angle of 1.0 degree and dynamic pressures within 0.03 with 95% certainty. The variations in the calibration data due to Reynolds number are also discussed. For the range of Reynolds number employed, no effect was detected on the pitch, yaw and total pressure coefficients. However, the static pressure coefficient showed change to cause minor variations in the magnitude of the calculated velocity vector. To account for these variations, average correction factors need to be incorporated into the static pressure coefficient.

비영위법에 의한 5공 프로브의 교정에 관한 연구 (A Study on the Five-hole Probe Calibration with Non-nulling Method)

  • 정양범;신영호;박호동
    • Journal of Advanced Marine Engineering and Technology
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    • 제20권2호
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    • pp.48-56
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    • 1996
  • This paper is concerned with a method for calibrating five-hole probes of both angle-tube and prismatic geometries to measure local total and static pressures and the magnitude and direction of the mean velocity vector. Descriptions of the calibration technique, the typical calibration data, and an accompanying discussion of the interpolation procedure are included. The flow properties are determined explicitly from measured probe pressures using calibration data. Flow angles are obtained within the deviation angle of 1.0 degree and dynamic pressures within 0.03 with 95% certainty. The variations in the calibration data due to Reynolds number are also discussed. For the range of Reynolds number employed, no effect was detected on the pitch, yaw abd total pressure coefficients. However, the static pressure coefficient showed change to cause minor variations in the magnitude of the calculated velocity vector. To account for these variations, average correction factors need to be incorporated into the static pressure coefficient.

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The effect of Gas Mixture Ratio on Discharge Characteristics of an AC PDP Cell

  • Lee, Hae-June;Lee, D.K.;Choi, J.H.;Cho, Y.S.;Park, H.D.;Lee, H.J.;Park, C.H.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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    • pp.171-174
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    • 2005
  • Experimental measurements are reported and compared with the results of a two-dimensional fluid simulation for the investigation of the discharge characteristics regarding the change of the mixture ratio of Ne-Xe-He noble gases. The increase of Xe contents results in the increases of luminance and luminous efficiency while it also results in the increase of the breakdown voltage and the discharge time lag. The addition of He gas increases the brightness and the luminance efficiency. When Xe partial pressure is low, the luminance efficiency increases with the amount of He at the same total pressure. When Xe partial pressure is high, however, the luminance efficiency has a maximum value when the partial pressure of He is about 10% of the total pressure for a standard AC PDP cell with Xe fraction of $10{\sim}30%$.

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혈압 판별 분석 -위험요인을 중심으로- (The Discriminant Analysis of Blood Pressure - Including the Risk Factors -)

  • 오현수;서화숙
    • 대한간호학회지
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    • 제28권2호
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    • pp.256-269
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    • 1998
  • The purpose of this study was to evaluate the usefulness of variables which were known to be related to blood pressure for discriminating between hypertensive and normotensive groups. Variables were obesity, serum lipids, life style-related variables such as smoking, alcohol, exercise, and stress, and demographic variables such as age, economical status, and education. The data were collected from 400 male clients who visited one university hospital located in Incheon, Republic of Korea, from May 1996 to December 1996 for a regular physical examination. Variables which showed significance for discriminating systolic blood pressure in this study were age, serum lipids, education, HDL, exercise, total cholesterol, body fat percent, alcohol, stress, and smoking(in order of significance). By using the combination of these variables, the possibility of proper prediction for a high-systolic pressure group was 2%, predicting a normal-systolic pressure group was 70.3%, and total Hit Ratio was 70%. Variables which showed significance for discriminating diastolic blood pressure were exercise, triglyceride, alcohol, smoking, economical status, age, and BMI (in order of significance). By using the combination of these variables, the possibility of proper prediction for a high-diastolic pressure group was 71.2%, predicting a normal-diastolic pressure group was 71.3%, and total Hit Ratio was 71.3%. Multiple regression analysis was performed to examine the association of systolic blood pressure with life style-related variables after adjustment for obesity, serum lipids, and demographic variables. First, the effect of demographic variable alone on the systolic blood pressure was statistically significant (p=.000) and adjusted $R^2$was 0.09. Adding the variable obesity on demographic variables resulted in raising adjusted $R^2$to 0.11 (p=.000) : therefore, the contribution rate of obesity on the systolic blood pressure was 2.0%. On the next step, adding the variable serum lipids on the obesity and demographic variables resulted in raising adjusted R2 to 0.12(P=.000) : therefore, the contribution rate of serum lipid on the systolic pressure was 1.0%. Finally, adding life style-related variables on all other variables resulted in raising the adjusted $R^2$to 0.18(p=.000) ; therefore, the contribution rate of life style-related variables on the systolic blood pressure after adjustment for obesity, serum lipids, and demographic variables was 6.0%. Multiple regression analysis was also performed to examine the association of diastolic blood pressure with life style-related variables after adjustment for obesity, serum lipids, and demographic variables. First, the effect of demographic variable alone on the diastolic blood pressure was statistically significant (p=.01) and adjusted $R^2$was 0.03. Adding the variable obesity on demographic variables resulted in raising adjusted $R^2$to 0.06 (p=.000) ; therefore, the contribution rate of obesity on the diastolic blood pressure was 3.0%. On the next step, adding the variable serum lipids on the obesity and demographic variables resulted in raising the adjusted $R^2$ to 0.09(p=.000) ; therefore, the contribution rate of serum lipid on the diastolic pressure was 3.0%. Finally, adding life style-related variables on all other variables resulted in raising the adjusted $R^2$ to 0.12 (p=.000) : therefore, the contribution rate of life style-related variables on the systolic blood pressure after adjustment for obesity, serum lipids, and demographic variables was 3.0%.

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Multiple Orifice Technique for Pressure Drop in Compressible Pipe Flows

  • Kim, Heuy-Dong;Koo, Byoung-Soo;Woo, Sun-Hoon;Setoguchi, Toshiaki
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 춘계학술대회논문집B
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    • pp.459-464
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    • 2000
  • In order to investigate the effectiveness of an orifice system in producing pressure drops and the effect of compressibility on the Pressure drop, computations using the mass-averaged implicit Wavier-Stokes equations were applied to the axisymmetric pipe flows with the operating pressure ratio from 1.5 to 20.0. The standard k-e turbulence model was employed to close the governing equations. Numerical calculations were carried out for some combinations of the multiple orifice configurations. The present CFD data showed that the orifice systems, which have been applied to incompressible flow regime to date, can not be used for the hint operating Pressure ratio flows. The orifice interval did not strongly affect the total pressure drop but the orifice area ratio more than 2.5 led to high pressure drops. The total pressure drop rapidly increased in the range of the operating pressure ratio from 1.5 to 4.0, but it did not depend on the operating pressure ratio over 4.0.

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성인 편마비 환자의 편측 무시정도에 따른 족저압 비교 (The Comparison of Plantar Pressure Distribution regarding the Extent of Hemineglect in Adult Hemiplegia)

  • 차용준;김경
    • 대한물리의학회지
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    • 제5권1호
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    • pp.43-51
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    • 2010
  • Purpose : The purpose of this study was to compare plantar pressure distribution between affected side and unaffected side and to analyze plantar pressure distribution of affected side according to the extent of hemineglect in the adult hemiplegia. Methods : Twenty-five hemiplegia participated in this study. The analysis of plantar pressure distribution was conducted by the F-scan system, and the extent of hemineglect was evaluated with line-bisection test. While the subject walked about 10 meters in their comfortable speed the plantar pressure was evaluated and stored. Results : Total contact area, AP CoP trajectory, contact pressure of mid-foot of the affected side were significantly different from the unaffected side. Total contact area, AP CoP trajectory and contact pressure of mid-foot were smaller than those of unaffected side. In the comparison among the group according to the extent of hemineglect, AP CoP trajectory of subject who has severe hemineglect was significantly different from the patient that has no hemineglect and it was shorter than that of no hemineglect. Conclusion : The plantar pressure distribution was generally different between affected side and unaffected side and the hemineglect affected negatively the patient to move CoP forwardly while walking. Accordingly, it will help the clinician to understand the hemineglect which has an effect on abnormal walking and to intervent the hemiplegia who has a neglection to the affected side.

원주방향 균열의 균열열림에 미치는 압력유기굽힘의 구속 효과 (Effect of Restraint of Pressure Induced Bending on Crack Opening for Circumferential Crack)

  • 김진원;박치용
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 추계학술대회논문집A
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    • pp.849-855
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    • 2000
  • This study evaluated the effect of restraint of pressure induced bending(PIB) on crack mouth opening displacement(CMOD) for circumferential through-wall crack in pipe by using both elastic and elastic-plastic finite element analyses. The analyses results showed the restraint of PIB was decreased crack opening for a given crack length and tensile stress, and the effect was considerable for large crack and short restraint length. Also, the restraint effect on CMOD was independent on the variation in pipe diameter and decreased with increasing pipe thickness, and it depended on not total restraint length but short restraint length for non-symmetrically restrained. Additionally, the effect of restraint of PIB was more significant in the elastic-plastic analysis results compared with in the elastic analysis results.

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Growth of nickel-catalyzed carbon nanofibers using MPCVD method and their electrical properties

  • Kim, Sung-Hoon
    • 한국결정성장학회지
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    • 제14권1호
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    • pp.1-5
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    • 2004
  • Carbon nanofilaments were formed on silicon substrate via microwave plasma-enhanced chemical vapor deposition method. The structure of carbon nanofilaments was identified as the carbon nanofibers. The extent of carbon nanofibers growth and the diameters of carbon nanofibers increased with increasing the total pressure. The growth direction of carbon nanofibers was horizontal to the substrate. Laterally grown carbon nanofibers showed the semiconductor electrical characteristics.

추마요법이 본태성 고혈압 환자의 혈압하강에 미치는 효과 (The Effects of Chu-ma Therapy on Decreasing Blood Pressure in Essential Hypertension)

  • 김남선
    • 대한간호학회지
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    • 제30권4호
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    • pp.967-981
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    • 2000
  • The purpose of this study is to evaluate the effects of Chu-ma therapy and to suggest that the therapy is an effective nursing intervention tool to reduce blood pressure. The research design employed was the non-synchronized research method with non- equivalent control group. A total of 30 people with essential hypertension, who were from forty to sixty five years old, participated in the study. The Chu-ma therapy was administered by every day for ten or fifteen minutes for eight weeks from 19, April to 13, June in 1999. In order to evaluate the effects of Chu-ma therapy, blood pressure of the two groups were measured once a week, and physiological parameters (epinephrine, norepinephrine, total cholesterol, HDL-cholesterol, triglycerides) were measured before and after the treatment. Collected data was analyzed by SAS package. The results of this study can be summarized as follows : 1) There were significant decrease in systolic blood pressure and diastolic blood pressure in the experimental group. 2) There were no significant changes in epinephrine, norepinephrine of the two groups. 3) There were significant decrease in total cholesterol and triglycerides, and HDL- cholesterol increased significantly in the experimental group. 4) The effect of Chu-ma therapy on the measured time on the blood pressure in experimental group was as follows: Both of systolic and diastolic blood pressures were significantly decreased after 5weeks. The result proved that Chu-ma therapy is an effective nursing intervention tool for clients with essential hypertenion. However further research is still necessary to compare the effect with the different periods and number of times for Chu-ma therapy.

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정상생활을 하는 고혈압 여성에 있어서 일상적인 나트륨, 칼슘 섭취습관이 혈압조절 관련 호르몬에 미치는 영향 (The Effect of Habitual Calcium and Sodium Intakes on Blood Pressure Regulating Hormone in Free-Liveing Hypertensive Women)

  • 박정아;윤진숙
    • Journal of Nutrition and Health
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    • 제34권4호
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    • pp.409-416
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    • 2001
  • In order to evaluate the effect of habitual Na and Ca intake on blood pressure regulation, we measured the habitual dietary intakes of Na and Ca, urinary excretion of Ca, Na and K, and plasma level of renin activity, aldosterone, and indices of Ca metabolism in 27 untreated hypertensive women and 30 age-matched normal women on a free diet. Hypertensive and total subjects were divided into four groups according to habitual dietary intakes of Na and Ca as low Na-low Ca(LNLC), low Na-high Ca(LNHC), high Na-low Ca(HNLC), and high Na-high Ca(HNHC). HNLC hypertensive group showed the lowest level of plasma renin activity, 25-(OH) Vit D$_3$, calcitonin and serum total Ca, and presented the highest level of PTH and urinary excretions of Na/K and Ca/Cr. There were no significant difference in plasma level of aldosterone and urinary excretion of Na and K among four hypertensive groups. When all subjects were divided into four groups according to the same method, HNLC group showed the highest level of blood pressure with no statistical significance and the lowest level of calcitonin and total serum Ca. The above results indicated that renin-aldosterone system and Ca regulating hormone has a mutual relationship in hypertension. Na and Ca may interact each other, rather than affecting independently blood pressure control. As a result, considering the fact that daily balance of Na and Ca intakes affects Na and Ca regulating hormones and urinary excretion of Na and Ca, it may be involved in blood pressure control. These results suggest that maintaining an adequate intake of Ca with less intake of Na may prevent from the risk of hypertension. (Korean J Nutrition 34(4) : 409~416, 2001)

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