• Journal of The Korean Society of Agricultural Engineers
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• v.61 no.5
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• pp.23-31
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• 2019

Crop response to weather and internal water pressure changes is more sensitive to crop water stress than soil water content. Recently, its implementation to optimal irrigation scheduling has been receiving much attention. This study was conducted to determine and compare the theoretical crop water stress index (CWSI) using meterological data and canopy temperature collected from three different irrigation treatments, which were Tr-1 plot (rainfed), Tr-2 plot (50% of daily evapotranspiration (ET) irrigated) and Tr-3 plot (75% of daily evapotranspiration (ET) irrigated). The readings of canopy temperature and CWSI were significantly different among irrigation treatment schemes. The average canopy temperatures and CWSIs of Tr-1 and Tr-3 plots were $34.6^{\circ}C$ and $32.6^{\circ}C$, 0.79 and 0.64, respectively. Solar radiation had the biggest correlation with CWSI (R=0.68) which was followed by wind speed, relative humidity and air temperature. Overall, the findings of this study indicated that canopy temperatures and CWSIs could be further used for irrigation scheduling for crop growth.

• The Journal of Internal Korean Medicine
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• v.31 no.2
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• pp.314-330
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• 2010

Objective : This study was performed to investigate the anti-fibrogenic effect and changes of inflammation-related genes by YBR I and YBR II (YBR I: Arteisiae Capillaris Herba, Atractylodis Rhizoma Alba, Hoelen/ YBR II: YBR I +Sanguisorbae Radix, Biotae Cacumen, Cirsii Japonici Herba) on HSC(hepatic stellate cells)-T6 and TAA-induced rat liver tissue. Materials and Methods : HSC-T6 were treated with various concentrations of distilled-water extract YBR I and YBR II extract for 24, 48 and 72 hours. After the treatment, cell viability, proliferation, procollagen levels and IL-6 levels were measured by using MTT Assay, BrdU Assay, Procollagen Type 1 C-peptide EIA kit, and Murine IL-6 ELISA Development kit. Rat liver fibrosis was induced by intraperitoneal TAA injection of 150mg/kg 3 times a week for 6 weeks. After the treatment, body weight, liver & spleen weights, liver function test, complete blood cell count and change of portal pressure were studied. In addition, gene expressions of ASMA, IL-6, MMP-2, TIMP-1 and TIMP-2, all of which are known to be associated with liver fibrosis, were analyzed by using Real-Time PCR. After YBR I and YBR IItreatment, percentages of collagen in TAA-induced rat liver tissue were measured. Results : The viability and proliferation of the HSC-T6 decreased as the concentration increased. The production of procollagen decreased as the concentration increased. The production of IL-6 was little influenced by YBR I and YBR II. There was no difference in rat body weight between the TAA-only group and the YBR groups. Compared with rat liver weight of TAA-only group, that of the YBR groups increased. In the YBR I group, the serum level of AST elevated by TAA injection significantly decreased and in the YBR I and II group, the serum level of ALP and ALT elevated by TAA injection decreased. In the YBR I group, white blood cell count elevated by TAA injection decreased but platelets increased. In the YBR I group, the portal pressure elevated by TAA injection significantly decreased. Decreases in the gene expression of ASMA and MMP-2 were observed in the YBR I group. The gene expression of IL-6 was little influenced by YBR I and YBR II -treated groups. In the histological finding, TAA injections caused severe fibrosis, but YBR I and YBR II treatment significantly reduced the amounts of hepatic collagens. Conclusions : These results suggest that YBR I and II have inhibitory effects on the hepatic fibrogenesis.

• Elastomers and Composites
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• v.11 no.2
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• pp.113-121
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• 1976

Fundamental and specific properties of the tennis ball on rubber ball body are surveyed to match the quality of the tennis ball now on applied in the tennis game, 1. Much dose of filler of non-crystalline or flat form applied to rubber compounding than general procedure and over vulcanization is found excellent in the resistant to gas permeability. 2. Flat curing improved characteristics of the ball on the homogenous rebounds when applied on the specified concrete surface. 3. Satisfactory adhesive power is found with Desmodur R and standard rubber recipe in case of applying on the under-vulcanizate of half sphere. 4. The stable gas-generating compounds of sodiun nitrate, ammonium chloride, water and sodium carbonate, anhydorus help controlling of optimum internal over-pressure in the tall.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1447-1452
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• 2012

Existing hydraulic valve meter used in industrial fields precise pressure measurement gives inconvenience in precise measurement due to manually regulated pressures. In order to improve this inconvenience, the hydraulic valve meter was designed by using automatic design program CATIA and structural analysis of the designed hydraulic valve meter was conducted and internal water leaking, stress, strain and total deformation were obtained by applying three dimensional finite element code ANSYS. These results will be provided to develop new concepts of hydraulic valve meters as fundamental data.

• Journal of computational fluids engineering
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• v.11 no.4 s.35
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• pp.56-61
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• 2006

Numerical simulation has been performed to investigate the characteristics of the mist flow through the fire suppression nozzles. The commercial CFD software, FLUENT with the proper modeling was applied for analyzing both the internal and external flow of the spray nozzles. Computations were made for the full cone nozzle in the operation range of the low pressure and high flow-rate. To validate the present computational procedure, numerical results are compared with measurements in terms of K-factor, SMD, axial spray velocity and spray angles. Numerical results suggested that the present numerical model can be used as an adequate tool for a design purpose of mist-spray nozzles.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2000.11a
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• pp.43-49
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• 2000

Heat transfer characteristics of self oscillating heat pipe were experimentally investigated for the effect of fill charge ratios and heat loads. The heat pipe used for this study is made of copper capillary, has 0.002m internal diameter, a 0.34m length in one turn and consists of 19 turns. Heating and cooling section each have a length of 70mm. Water was used as working fluid inside heat pipe. As the experimental results, the self oscillating heat pipe was operated by self-exited oscillation and circulation of working fluid and the oscillation within the self oscillating heat pipe assumed chaotic behavior.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.606-609
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• 2009

Development of renewable energy is very important because of environmental problems caused by greenhouse effect. This is due to the use of fossil fuels which has serious consequences. Therefore, development of small hydropower can be a good countermeasure for the problems. The small hydropower is clean energy because the small hydropower generates few $CO_2$. Moreover, as the energy density by the small hydropower is high, it is economical for a society which wants to introduce the system. The purpose of this study is to improve the turbine performance. This study is about tubular-type hydro turbine among renewable energy that is based using the different water pressure level in pipe lines. The analysis was performed using the commercial CFD code ANSYS-CFX.

• Journal of Biosystems Engineering
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• v.22 no.2
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• pp.199-209
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• 1997

A one-pass rice whitener with hard metal blades was developed to solve the problems of the existing one-pass rice whitener. The developed one-pass rice whitener was tested and improved through various milling experiments. It showed high performance such as the capacity of 3.5 t/h, the energy consumption of $1.0 kWh/100kg$, milled rice recovery of 91.6%, broken rice rate of 2.2%, the crack rate of 1.9% at the 750 rpm of the roller shaft, compared with those other domestic and foreign one-pass rice whiteners. Especially, it could whiten broun rice of high moisture (16～l7%) with water sprayed at low internal pressure of less than $0.2 kg/cm^2$ and low temperature due to the characteristics of the cutting part composed of 24 hard metal blades. The developed one-pass rice whitener was industrilized and distributed to some rice processing complexs in one fourth price compared with that of imported one-pass rice whiteners.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1522-1527
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• 2004

The purpose of this study is to investigate the effect of swirler angle and swirl chamber aspect ration of nozzle on the characteristics of single and twin spray. The performances of nozzle has been investigated by measurements of spray angle, droplet size, velocity and Weber number at a water pressure 0.4MHz. Visualization of spray was conducted to obtain the spray angle and breakup process. The spray characteristics such as droplet size and velocity were measured by Phase Doppler Anemometry(PDA). It was found that the smaller swirler angle, the larger axial velocity became. It was also shown that the larger aspect ratio, the smaller droplet diameter became.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.25 no.6
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• pp.303-309
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• 2013

For air-tight modern buildings, secondary damage is likely to occur due to condensation in the relatively high heat-transmission windows since water vapor is not easy to discharge. Therefore, in this study, condensation performance of vacuum glazing was numerically analysed, compared with that of ordinary glass and confirmed experimentally by three sheets of vacuum glazing manufactured. The results show that the heat transmission coefficient of the vacuum glazing whose internal pressure is $10^{-3}$ torr was as low as about $5.7W/m^2{\cdot}K$. Thus, the condensation performance as well as the adiabatic performance was greatly improved compared to that of the ordinary glass.