• Korean Journal of Ecology and Environment
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• v.38 no.spc
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• pp.44-53
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• 2005

The Nakdong River, which lies in a monsoon climate zone with warm rainy summers and cold dry winters, is a typical ecosystem showing the attributes of a regulated river. In 2003, the total annual rainfall (1,805 mm) was higher than the average of the past nine years from 1994 to 2002 (1,250 mm). In September a powerful typhoon, Maemi, caused a big impact on the limnology of the river for over two months. Among the limnological variables, turbidity in 2003 (37.4 ${\pm}$ 94.1 NTU, n = 54) was higher than the annual average for ten years (18.5 ${\pm}$ 2.3 NTU, n = 486) in the lower part of the river (Mulgum: RK 28). Furthermore, physical disturbance (e.g. stream bank erosion within channel) in the upstream of the Imha Dam (RK ca. 350; river distance in kilometer from the estuary barrage) in the upper part of the river was a source of high turbidity, and impacted on the limnological dynamics along a 350 km section of the middle to lower part of the river. After the typhoon, high turbidity persisted more than two months in the late autumn from September to November in 2003. Flow regulation and the extended duration of turbid water are superimposed on the template of existing main channel hydroecology, which may cause spatial changes in the population dynamics of plankton in the river.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.1
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• pp.25-37
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• 2008

When livestock facilities in Korea have been changed larger and denser, rearing conditions have been getting worse and the productivity of animal production have been decreased. Especially in the cold season, the minimized ventilation has generally been operated to save energy cost in Korea resulting in very poor environmental condition and high mortality. While the stability, suitability, and uniformity of the rearing condition are the most important for high productivity, the ventilation configuration is the most important to improve the rearing condition seasonally. But, it is so difficult to analyze the internal air flow and the environmental factors by conducting only field experiment because the weather condition is very unpredictable and unstable as well as the structural specification can not be easily changed by the researchers considering cost and labor. Accordingly, an aerodynamic computer simulation was adopted to this study to overcome the weakness of conducting field experiment and study the aerodynamic itself. It has been supposed that the airflow is the main mechanism of heat, mass, and momentum transfers. To make the simulation model accurately and actually, simplified pig models were also developed. The accuracy of the CFD simulation model was enhanced by 4.4 % of errors compared with the data collected from field experiments. In this paper, using the verified CFD model, the CFD computed internal rearing condition of the mechanically ventilated pig house were analyzed quantitatively as well as qualitatively. Later, this developed model will be computed time-dependently to effectively analyze the seasonal ventilation efficiency more practically and extensively with tracer gas decay theory.

• Journal of the Korean Society of Physical Medicine
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• v.2 no.2
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• pp.151-159
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• 2007

Purpose : The purpose of the study was to investigate the effect of cold application on knee joint in rats induced by osteoarthritis. Methods : Osteoarthritis was induced in female Sprague-Dowley rats by injecting into articular cavity of knee joint with 4% Kaolin, 2% carrageenan. Rats were divided randomly into the control and MES applicated group. The Experimental group was applicated MES in rat knee joint for 30 minutes. Results : Recovery of articular cartilage surface and thickness of articular cartilage increased after MES application. And chondrocytes were distributed widely throughout the cartilage matrix. The physical effects of Microcurrent Electrical Stimulation. Decrease in blood flow. Delay of neurotransmitter velocity Decrease in metabolism activity and inhibit the progress of the infection. Decrease in pain and muscle rigidity, inhibition of circulation Conclusion : This study shows that MES application affects articular cartilage recovery in osteoarthritis.

• International Journal of Highway Engineering
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• v.19 no.2
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• pp.17-24
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• 2017

PURPOSES : This study aims to develop a sealant for use in the installation of Weigh-In-Motion (WIM) sensor for asphalt concrete or cement concrete pavements. METHODS : In order to investigate the properties of various sealants that were mixed with latex and carbon fiber, various test methods were adopted, such as bituminous bond strength test, softening point test, and cone penetration test. To evaluate moisture susceptibility, the BBS test was conducted under moist condition. The bond strength ratio (BSR) was calculated based on tensile strength ratio method. RESULTS : The sealant's properties significantly varied according to the amount of latex or carbon fiber. The usage of latex marginally enhanced the cone penetration test result, notwithstanding reduced asphalt content. This implies that the sealant will be proper cold temperature reason. Moreover, the addition of latex and carbon fiber evidently increased the softening point. This indicates that the tendency of the material to flow at elevated temperatures is encountered during service. With the addition of latex and carbon fiber, the moisture susceptibility measured with BSR improved marginally, while the bond strength under dry condition decreased marginally. Sealant F displays the highest bond strength and BSR under limited test conditions. CONCLUSIONS : According to the proportion of latex and carbon fiber mixed, properties of sealant, such as softening point, cone penetration, and BSR varied marginally. This indicates that the sealant has to be applied considering the environmental condition, to improve service life.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.11
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• pp.991-998
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• 2013

A numerical study is carried out for natural convection in an enclosure with an inner hot cylinder at the center. The top wall is cold, the bottom and both side walls of the enclosure are adiabatic, and the cylinder is heated. The bottom wall is heated locally at the middle. The ratio (w) is defined by as the width of the bottom wall to that of the heated local area. The immersed boundary method (IBM) is used to model an inner circular cylinder based on the finite volume method (FVM). This study investigates the effect of w on natural convection in an enclosure with an inner heated cylinder for Rayleigh numbers of $10^6$. At $6Ra=10^6$, thermal and flow fields show time-dependent characteristics after their full development.

• The Korean Journal of Nuclear Medicine
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• v.28 no.3
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• pp.397-401
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• 1994

A twenty-one-year-old man visited our hospital due to abdominal distension for a month. On the physical examination, there was severe abdominal distension with fluctuation and shifting dullness. The routine laboratory results were within normal range. On the Magnetic Resonace angiography, there wasn't any blood flow within the right and middle hepatic vein. So we concluded that the etiologic disease was Budd-Chiari syndrome. On the liver scan, there was cold area(absence of radiouptake) on entire right lobe of the liver, increased uptake on the bone marrow and showed splenomegaly. This finding was similar to the liver mass occupying right lobe with underlying chronic liver disease. On the previous reports, it is quite uncommon finding that Budd-Chirari syndrome shows lesion like space occupying one on the liver scan. So we report this case with a review of the literature.

• 한국해양학회지
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• v.28 no.1
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• pp.35-46
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• 1993

To delineate water properties and current patterns in the spawning area of walleye pollock, hydrographic cast and current meter data collected in Strait, Gulf of alaska, were analysed, three water masses are identified in Shelikof Strait. A small amount of cold and dilute water ($<{\;}3^{\circ}C{\;}and{\;}<{\;}31.5\textperthousand$) originates from the lower Cook Inlet and flows southwestward close to the Alaska Peninsula coast. One branch of alaska coastal Current which enters the strait from the northeast comprises the main body of the upper and middle layers of the strait, and flows toward the southwest. Estimation of geostrophic baroclinic currents reveals that comparatively fast flow exists in the surface over the deepest portion of the strait, and most water exits through the southwestern entrance between Semidi and chirikof Is. On the other hand, a relatively slow-moving warm and saline ($>{\;}5^{circ}C{\;}and{\;}>{\;}32\textperthousand$) of the southwestern entrance flows northeasterly, and occupies the bottom layer in Shelikof Strait.

• Journal of Korean Society of Disaster and Security
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• v.13 no.1
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• pp.51-58
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• 2020

This paper analyzes the effect of airflow of ceiling air conditioner on the operation of sprinkler head using a simulation program. The simulation space is 10 m × 7 m × 3 m, and the size of the fire is 0.8 m × 0.8 m × 0.6 m. The cold air flow from the air conditioner is at 25℃ and the wind speed is divided into three cases : 10 ㎧, 8.5 ㎧, and 7.5 ㎧. Simulation results show that all cases had operating delays compared to when the air conditioner was not running, and the sprinkler head did not operate until 10 minutes had elapsed at 10 ㎧ wind speed. These results confirmed that the sprinkler head was delayed in the air conditioning space and the worst result of early evolution failure was observed in strong winds such as 10 ㎧.

• Journal of Energy Engineering
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• v.2 no.1
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• pp.95-103
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• 1993

A conceptual thermoelectric heat pump(cooling mode) of small capacity is designed. Its performance is investigated through parametric analysis. COP and cooling capacity decease as the ambient temperature increases with ${\mu}$, J, T$\sub$wi/, fixed. To design a system of fixed capacity comes to calculate ${\mu}$ and J when T$\sub$wi/, and T$\sub$a/ are given. As v is fixed by semi-conductor manufacturers, optimum combination of n and I should be searched for ν. Optimum current could be calculated using ${\mu}$-J curve and optimum value of ${\mu}$. COR$\sub$R/ increases as water flow rate increases and T$\sub$a/ decreases. The effect of heat transfer coefficient at hot(heat releasing) side is more significant than that at cold(heat absorbing) side.

• Journal of the Korean Solar Energy Society
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• v.29 no.2
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• pp.31-38
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• 2009

This study was conducted to forecast inner water temperature strata change by extracting deep water from a dam. For the methodology, the scope wherein the balance between the volume of low-temperature water intake through the virtual water intake opening as installed within the stored water area and the volume of water intake from the surrounding area is not destroyed was calculated through the CFD simulation technique using the computational fluid dynamics(CFD) interpretation method. This study suggested a supplementary method(diffuser) to avoid destroying the water temperature strata, and the effect was reviewed. In case of intake of the same volume, when the velocity of flow of water intake is reduced by increasing the pipe diameter, the destruction of water temperature strata can be minimized. When the area(height) where the intake of water is possible is low, a diffuser for interrupting the vertical direction inflow should be installed to secure favorable water intake conditions in case of water intake on the upper part. This study showed that there was no problem if the intake-enabled, low-temperature area was secured approximately 10m from the bottom when the scope that does not destroy the water temperature strata in case of water intake was forecast using the regression formula.