• 한국분무공학회지
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• 제9권4호
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• pp.83-89
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• 2004

Vaporization characteristics of a liquid heptane droplet in high-pressure and temperature flow field are numerically studied. Variable thermodynamic and transport properties and high-pressure effects are taken into account in order to consider real gas effects. Droplet Vaporization in convective environments was investigated on the basis of droplet vaporization in quiescent and convective environment. In quiescent environments, droplet lifetime is directly proportional to pressure at the subcritical temperature range but it is inversely proportional to pressure at the supercritical temperature range. In convective environment, droplet deformation becomes stronger by increasing Reynolds number due to increase of velocity while droplet deformation is relatively weak at a higher pressure for the same Reynolds number cases.

• 한국표면공학회지
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• 제40권4호
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• pp.180-184
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• 2007

A new zirconium alloy, low-Sn Zircaloy-4 was investigated to see the effects of high pressure steam on the oxidation at high temperatures. High pressure steam turned out to enhance the oxidation at high temperatures below $1000^{\circ}C$. The oxide layer groved to deviate from the uniform layer under high steam pressures, and usually cracks were found at the thicker parts in the oxide layer. High pressure steam seems to destabilize the tetragonal oxides near the metal layer, and the monoclinic oxides transformed from the destabilized tetragonal oxides are structurally not sound, resulting in enhanced oxidation under high pressure steam.

• Wind and Structures
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• 제24권2호
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• pp.145-169
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• 2017

The auxiliary structures of a high-rise building, such as balconies, ribs, and grids, are usually much smaller than the whole building; therefore, it is difficult to simulate them on a scaled model during wind tunnel tests, and they are often ignored. However, they may have notable effects on the local or overall wind loads of the building. In the present study, a series of wind pressure wind tunnel tests and high-frequency force balance (HFFB) wind tunnel tests were conducted on rigid models of an actual super high-rise building with vertical ribs protruding from its facades. The effects of the depth and spacing of vertical ribs on the mean values, fluctuating values and the most unfavorable values of the local wind pressure coefficients were investigated by analyzing the distribution of wind pressure coefficients on the facades and the variations of the wind pressure coefficients at the cross section at 2/3 of the building height versus wind direction angle. In addition, the effects of the depth and spacing of vertical ribs on the mean values, fluctuating values and power spectra of the overall aerodynamic force coefficients were studied by analyzing the aerodynamic base moment coefficients. The results show that vertical ribs significantly decrease the most unfavorable suction coefficients in the corner recession regions and edge regions of facades and increase the mean and fluctuating along-wind overall aerodynamic forces.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.25-34
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• 2008

In this paper, three-dimensional multiblade row unsteady Navier-Stokes simulations at a hot streak temperature ratio of 2.0 have been performed to reveal the effects of rotor tip clearance on the inlet hot streak migration characteristics in low pressure stage of a Vaneless Counter-Rotating Turbine. The hot streak is circular in shape with a diameter equal to 25% of the high pressure turbine stator span. The hot streak center is located at 50% of the span and the leading edge of the high pressure turbine stator. The tip clearance size studied in this paper is 2.0mm(2.59% high pressure turbine rotor height, and 2.09% low pressure turbine rotor height). The numerical results show that the hot streak is not mixed out by the time it reaches the exit of high pressure turbine rotor. The separation of colder and hotter fluid is observed at the inlet of low pressure turbine rotor. Most of hotter fluid migrates towards the rotor pressure surface, and only little hotter fluid migrates to the rotor suction surface when it convects into the low pressure turbine rotor. And the hotter fluid migrated to the tip region of the high pressure turbine rotor impinges on the leading edge of the low pressure turbine rotor after it goes through the high pressure turbine rotor. The migration of the hotter fluid directly results in very high heat load at the leading edge of the low pressure turbine rotor. The migration characteristics of the hot streak in the low pressure turbine rotor are dominated by the combined effects of secondary flow and leakage flow at the tip clearance. The leakage flow trends to drive the hotter fluid towards the blade tip on the pressure surface and to the hub on the suction surface, even partial hotter fluid near the pressure surface is also driven to the rotor suction surface through the tip clearance. Compared with the case without rotor tip clearance, the heat load of the low pressure turbine rotor is intensified due to the effects of the leakage flow. And the numerical results also indicate that the leakage flow effect trends to increase the low pressure turbine rotor outlet temperature at the tip region.

• Asian-Australasian Journal of Animal Sciences
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• 제19권10호
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• pp.1484-1489
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• 2006

This study was carried out to investigate the effect of high pressure and the addition of non-meat proteins on the physico-chemical and binding properties of restructured pork. Pressurizations were carried out at up to 200 MPa and non-meat proteins used as a binder were isolated soy protein (ISP), sodium caseinate (SC), whey protein concentrate (WPC) and egg white powder (EWP). The pH values of all treatments were affected by the level of pressure. $L^*$-value of all treatments increased significantly (p<0.05), while both $a^*$-value and $b^*$-value of all treatments showed a significant decrease (p<0.05) with increasing pressure level. Binders could contribute only additive effects on both pH and color of the treatments. It was found that high pressure improved the water binding capacities and binding strength of the treatments. Binders also improved the binding strength of restructured pork. However, SC and WPC had no effect on water binding properties under high pressure. These results indicate that the application of high pressure had more significant effect on restructuring meat than binders.

• 가정과삶의질연구
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• 제27권5호
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• pp.195-206
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• 2009

The main purpose of this study was to examine the effects of maternal achievement pressure and emotional support on adolescents' achievement motivation. A total of 241 adolescents in the second grade of two middle schools in Seoul and their mothers participated in the study, and completed questionnaires on mothers' achievement pressure and emotional support. Adolescents also answered a questionnaire on achievement motivation. Sohn's(1997) Achievement Pressure Scale, Sung's(1993) Social Support Scale and Hermans'(1970) Prestatie Motivatie Scale were used for this survey. Data were analyzed by Pearson's correlation coefficients, t-tests, regressions, and one-way ANOVA with Duncan's multiple range tests. Results showed that maternal achievement pressure and emotional support and adolescents' achievement motivation did not vary as a function of sex. Maternal achievement pressure and emotional support had positive effects on achievement motivation of adolescents, and maternal achievement pressure played a more influential role on the motivation of adolescents than emotional support. Among four groups divided by the level of maternal achievement pressure and emotional support, high/high, high/low, low/high, and low/low, adolescents in the high/high group were perceived to have the highest achievement motivation. Findings suggest that both maternal achievement pressure and emotional support are important in improving adolescents' achievement motivation.

• International Journal of Advanced Culture Technology
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• 제6권4호
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• pp.205-213
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• 2018

This research is about effects of obesity adults participating in 12weeks of boxing diets program on weight loss, blood pressure and blood sugar improvements. The exercise program was conducted three times a week with a maximum heart rate of 50 to 65 percent for first to forth weeks and 65 to 85 percent for fifth to twelfth. The study included 59 obese people in their 20s and 50s, with a BMI of 25kg/m2 or higher, blood pressure of 140/90mmHg, and high blood pressure and diabetes patients of 125 mg/dl per fasting blood sugar. The following results were obtained by observing the results before and after the boxing exercise program. High blood pressure, diabetes, high blood pressure + diabetes after 12 weeks showed significant weight, BMI and body fat reduction, as well as significant decrease in blood pressure and fasting blood sugar. Consequently, through this study, obese adults can lower their weight, blood pressure, and blasting fasting blood sugar through a 12-week high-strength boxing exercise program and it is believed to help improve and prevent obesity, cardiovascular disease and metabolic diseases.

• 한국축산식품학회지
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• 제36권3호
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• pp.335-342
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• 2016

The object in this study is to investigate the effects of high pressure and freezing processes on the curdling of skim milk depending on the presence of transglutaminase (TGase) and glucono-δ-lactone (GdL). Skim milk was treated with atmospheric freezing (AF), high pressure (HP), pressure-shift freezing (PSF) and high pressure sub-zero temperature (HPST) processing conditions. After freezing and pressure processing, these processed milk samples were treated with curdling agents, such as TGase and GdL. Pressurized samples (HP, PSF and HPST) had lower lightness than that of the control. In particular, PSF had the lowest lightness (p<0.05). Likewise, the PSF proteins were the most insoluble regardless of whether they were activated by TGase and GdL, indicating the highest rate of protein aggregation (p<0.05). Furthermore, the TGase/GdL reaction resulted in thick bands corresponding to masses larger than 69 kDa, indicating curdling. Casein bands were the weakest in PSF-treated milk, revealing that casein was prone to protein aggregation. PSF also had the highest G' value among all treatments after activation by TGase, implying that PSF formed the hardest curd. However, adding GdL decreased the G' values of the samples except HPST-treated samples. Synthetically, the PSF process was advantageous for curdling of skim milk.

• 산업식품공학
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• 제15권1호
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• pp.70-74
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• 2011

전분필름의 물성에 미치는 고압균질 처리의 영향을 검토한 결과, 고압균질처리 옥수수전분필름은 산화전분필름과 유사한 투명도를 가지며, 용해도와 산소투과억제력의 증가와 함께 인장강도가 다소 높아지는 것을 확인하였다. 이러한 고압균질처리 옥수수전분필름의 물성변화는 고압균질기의 고압과 전단력에 의해 호화전분입자가 완전히 소실되고 전분의 용해도 증가와 보다 균일한 분산상이 형성되기 때문으로 판단되었다. 일반적인 호화과정을 통해 형성되는 전분필름의 구조는 연속상의 아밀로오스에 팽윤된 접분입자가 분산되어 있는 network 형태에서 형성된다. 반면 고압균질처리의 경우, 호화전분입자의 붕괴로 아밀로펙틴이 연속상을 이루고 여기에 아밀로오스가 분산상으로 존재하는 새로운 분산계(dispersed system)가 형성되어, 기존 호화 방법으로 제조한 필름과 다른 물성을 나타내는 것으로 판단되었다.

• 한국축산식품학회지
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• 제31권5호
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• pp.641-648
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• 2011

This study investigated the effects of high pressure with or without thermal treatment on the cured color development and residual nitrite contents of model meat systems (pork, NaCl and sodium nitrite). At low nitrite levels (${\leq}50{\mu}g/g$), 200 MPa of pressure alone (P) did not develop the cured meat color (p>0.05). Thermal treatment (T) showed curing pigmentation (higher CIE L* and CIE a*), and the impacts were more effective when pressure was combined with thermal treatment (PT). In contrast, nitrite levels did not contribute to the cured meat color when ${\geq}200{\mu}g/g$ of nitrite was added to the meat. At high nitrite levels, although the typical cured color that is induced by thermal treatment did not present by pressure alone, the PT treatment still showed a pinker color with low residual nitrite content compared to the T treatment. The higher the pressure level (300 MPa), the greater the cured meat pigmentation with lower residual nitrite. Therefore, the present study demonstrates the possible application of high pressure, both for cured pigmentation and reducing residual nitrite, respective to typical thermal treatments.