• Journal of the Korean Society of Environmental Restoration Technology
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• v.14 no.5
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• pp.37-51
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• 2011

Research and conservation of plant species for the nation arboretum, collection and securing of the plant species for both public and private arboreta and education for the arboreta which is affiliated to the university are overall management goal of the arboreta in Korea. Most of the arboreta in Korea run the programs and events for guide and interpretation of forest, but the programs and events are not well specified by the arboreta. Regarding the reasonable level of entrance fee should be discussed further as the lack of information and understanding. But the specified entrance fee between public and private arboreta should be considered. An eighty three percent of arboreta in Korea has been properly managed the species information. The reasonable management should be considered in case of unusual management of collected plant genetic resources. Although the overall impending difficulties for the management of arboreta in Korea is the lack of trained or qualified staffs, securing tasks independently for the public arboreta and relatively low salary for the private arboreta are main difficulties. Most of the difficulties are derived from the lack of its mission of the arboreta. The management of arboreta by the mission statement is one of the core targets including the characters such as climate or region should be considered. The securing qualified or trained staffs should be considered in the development of arboreta in Korea including the modification of relevant regulations or law.

• Journal of Internet of Things and Convergence
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• v.8 no.2
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• pp.25-33
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• 2022

The purpose of this study is to provide the basic data for establishing a unique admissions promotion strategy for each university and to innovate the paradigm of university admissions promotion through the examples of central universities in the practice of PR promotion based on big data analysis. To this end, prior literature related to university publicity (marketing), and recognition of prospective college students who visited the university, and database data were defined and analyzed as big data. As a result, first, the preliminary studies related to college entrance exam promotion (marketing) increased dramatically in the 2000s and 2010s as part of preparing for countermeasures against population decline in school age. Responding to the need for an admissions promotion strategy to accelerate visits to prospective college students, the database data analysis result suggested the selection and concentration of entrance exam strategies based on the university's regional and academic characteristics.

• Journal of Energy Engineering
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• v.12 no.3
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• pp.223-230
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• 2003

A study was performed to measure and analyze the gas-side fouling of heat exchanger to cool the exhaust gas from sludge incinerator at ironworks. The incinerator gas passes through inside of the vertical tubes of heat exchanger to preheat the combustion air. This kind of fouling occurs at the entrance region of the heat exchanger and thus the perforated fouling plate was designed to measure the gas-side fouling and to analyze the particulate deposit. As a result of analysis, the particulate deposition rate was influenced by temperature, particulate composition and size and also the deposition patterns were different according to the location of perforated fouling plate. The computational analysis was performed to obtain the deposition rates at the perforated fouling plate and the calculation showed that the deposition rate was varied with the hole size and particulate size. It was proved that the fouling at the entrance region of heat exchanger could be measured by the perforated fouling plate designed in this study.

• Journal of Korean Society of Rural Planning
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• v.7 no.2 s.14
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• pp.33-40
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• 2001

The purpose of this paper is on identifying spatial structure of Palwang and Taechon village and dealing with restoration direction of village spatial structure and village groves. The results are as follows. It was identified that the standing stone for penis form is not standing stone for praying son but complementing that for enforcing enclosed function of enclosing village groves. It was considered that village entrance and entrance road, village grove of Taechon village must be restored for being identified as standing stone of penis form of spatial structure of village. It was considered that the above is essential to connect with ecotourism of Sunchang-gun region. It was identified that Palwang village grove is very good in conservation state, but Taechon village grove has been destructed mostly by various development. It was identified that Palwang village grove is high in species diversity and in scare value as mixed forest, landscape value. The dominent tree of Palwang village was Pinus densiflora and that of Taechon was Salix glandulosa. Salix glandulosa was used pavilion tree, main tree in both village. It was identified that Carpinus tschonoskii is showing the most rapid growth in tree height and Salix glandulosa is showing the most rapid growth in tree breadth diameter of all kind of tree. It was considered that Pinus densiflora was planted first of all and deciduous trees were complemented later. It was considered that simple forest of Pinus densiflora has been changed into mixed forest by artificial affect in the long term. It was considered that Salix glandulosa in Palwang village grove must be indicated as legal protection tree according to present criteria of protection tree selection in Korea. And it is considered desirable that standing stone of penis form and village grove in Palwang village must be indicated unitedly as cultural conservation element.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.2
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• pp.114-125
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• 2020

In order to understand the currents around Hampyung Bay and Haeje Peninsula, 2D numerical simulations for tidal currents and tide-induced residual currents were carried out. Dominant semidiurnal tidal currents have reversing form and flow NNE-SSW from northern Haeje Peninsula to Songi Island, E-S at northern Haeje Peninsula and NNW-SSE in Hampyung Bay. In flood, a part of currents from Imja Island~Nakwhol Island flow along the main stream flowing northeast at offshore region and the rest flow into Hampyung Bay flowing east along the northern coast of Haeje Peninsula. In ebb, currents from Hampyung Bay flow west along the northern coast of Haeje Peninsula and run together with the main stream flowing southeast at offshore region. The currents create an anticyclonic circulation in flood and a cyclonic circulation in ebb around Haeje Peninsula including Hampyung Bay. Tidal currents are accumulated on Doripo which located at the entrance of Hampyung Bay and show high current velocities. Tidal currents and tide induced residual currents are weak at the inside of Hampyung Bay which has narrow entrance, shallow water depth and wide intertidal zone. An anticyclonic eddy is formed around Gaksi Island as a result of tide induced residual currents. In northern coast of Haeje Peninsula, slow constant currents flow east. It is expected that a gradual change of sediment and an increase of flushing time for suspended materials are carried by tidal currents occurring in Hampyung Bay.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.12
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• pp.1007-1016
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• 2006

Although the advance in electronic technology enables a large number of circuity to be packed in a small volume, it is simultaneously required to remove the high heat load produced by them. In this study, the heat transfer and pressure drop characteristics of a mini-channel heat exchanger, which is designed for liquid cooling of electronic components, are investigated by varying operating conditions. Water and FC-72 were used as working fluids. The mini-channel heat exchanger was made with circular shape channels having din-meters of 2, 3, and 4 mm in regular intervals, and the channel length was 100 mm. The header and inlet guide pathway to provide uniform inflow were attached at the inlet of the test section. Copper block including the heaters was attached at the sidewall of the test section as a heat source, which provided the heat flux from 5 to $15W/cm^2$. The entrance effects enhanced the heat transfer coefficient in the mini-channel significantly. In addition, the single-phase pressure drop in the mini-channel was very similar to that predicted by the laminar flow correlation except that the transition Re decreased due to flow instability in the entrance region.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.33 no.4
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• pp.215-224
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• 2009

Analysis for various driven nozzle position changes. The analysis was done for different Reynolds number in entrance region of jet-pump and for several diameter ratios of driven nozzle. (1) The largest absorption energy was found at the point s=1 in condition of diameter ratio 1:3.21 and point s=0.5 in condition of diameter ratio 1:2.25. (2) The absorption energy was not related to the change of entrance velocity and the driven nozzle position having the largest absorption energy was function for cross section ratio. (3) As the position of driven nozzle moves to the downstream, the absorption energy gets weaker. Because the energy from swirl was lost at the cross section gets smaller. (4) As the position of driven nozzle moves to the downstream, the injection energy leans to the upper direction wall and as the Reynolds number increase, the lean phenomenon is more distinct. (5) The flow quantity of driven nozzle, the diameter ratio 1:3.21, was 32% higher than that of 1 : 2.25 and as the inlet velocity gets faster the efficiency decreased. And as the cross section of the driven nozzle increases.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.11 no.1
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• pp.1-11
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• 2015

Feedwater Heaters are important components in a nuclear power plant. As the age of heater increases, the maintenance cost required for continuous operation also increases. Most heaters have the carbon steel shells, tube support plates and flow baffles. The carbon steel is susceptible to flow-accelerated corrosion. This is especially true if the flow has a two-phase mixture of steam and condensate. The wall thinning around the wet steam entrance area of the shell is inevitable during some long term operation. The structural integrity of the feedwater heater shell affects the safe operation of the nuclear power plant. Therefore, it is needed for the thinned shell to be repaired. The maintenance method for preventing failure of the shell should be determined by investigating various factors including the stress distribution of thinned area. The stress analysis of the shell including the steam entrance region is studied in this paper. The results of thinned shell is compared with that of intact shell.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.6
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• pp.861-869
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• 1986

A numerical study has been conducted on the development of the velocity and temperature fields in a laminar flow through an eccentric annular duct. A bipolar coordinates system is adopted, and a numerical program is developed to analyze 3-dimensional parabolic flow problems. In the analysis of the velocity field, the entrance length has been defined as the distance where the axial pressure gradient is greater than that of the developed velocity field by 5%. The dimensionless hydrodynamic entry length increases with increasing eccentricity. In the transverse flow fields, the reverse flow region along the wall due to the developing axial velocity near the entrance of the duct is found. In the analysis of the temperature field, the thermal entry length has been defined as the axial distance where the mean fluid temperature is 5% less than that of the developed temperature field. The dimensionless thermal entry length increases as eccentricity or Prandtl number increases. The overshoot of the mean Nusselt number over the developed value at the zero-temperature wall is encountered, and the rate of the overshoot increases with the increase of the eccentricity and Prandtl number.

• Elastomers and Composites
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• v.22 no.3
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• pp.213-218
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• 1987

In this study, the rheological properties of a partially valcanized black filled EPDM were investigated as a function of degree of crosslinks using capillary rheometer. In order to obtain the samples having various degree of crosslinks between 0 and 6 percent, the vulcanization kinetics was also studied by Monsanto rheometer. The results showed that the die swell ana the pressure drop at the capillary entrance and exit increase nearly linearly with the increase in degree of crosslinks. However, melt fracture occurred at a lower shear rate for the samples of higher degree of crosslinks. These results were discussed in terms of the melt elasticity produced at the entrance region of capillary by the partial vulcanization. It is also interesting to note that the fluctuation of die swell during the practical extrusion or calendering process in the factories can be caused by the partial vulcanization occurred during the process.