• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.626-629
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• 2008

Numerical predictions on flow phenomena in pipe network systems have been considered as playing an important role in both designing and operating various facilities of piping or duct systems, such as water supply, tunnel or mine ventilation, hydraulic systems of automobile or aircraft, and etc. Traditionally, coupling conditions between junction and connected branches are assumed to satisfy conservation law of mass and to share an equal pressure at junction node. However, the conventional methodology cannot reflect momentum interactions between pipes sufficiently. Thus, a new finite volume junction treatment is proposed both to reflect the interchanges of linear momentums between neighbor branches at junction and to include the effect of wall at junction in present work.

• Journal of Environmental Impact Assessment
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• v.8 no.1
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• pp.141-146
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• 1999

This paper proposes the planning and design of the Eco-village centering around Chindo-ri, Muju-kun. The Eco-village project has three basic objects the Eco-village residents' lives adapting to ecological principles such as regeneration and circulation, life agricultural techniques based on organic cycle, and residents' harmonious lives with the surrounding nature. For constructing of the Eco-village, first, the subject area was analyzed in terms of the natural and cultural environment and then, on this analytic ground the concrete concept and the specific plan were set up. The following details also should be considered: the scale of the residential household, the population, the space arrangement of the village, the material cycling structure, the waste treatment, the purification of the sewage, the energy supply, the landscape architecture, the production activity, the conservation of the ecosystem and so on.

• Membrane and Water Treatment
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• v.7 no.1
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• pp.71-86
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• 2016

The present study deals with a numerical simulation for the transport phenomena in three configurations of Membrane Distillation (Air Gap, Direct Contact and Sweeping Gas Membrane Distillation) usually used for desalination in order to make an objective comparison between them under the same operating conditions. The models are based on the conservation equations for the mass, momentum, energy and species within the feed saline and cooling solutions as well as on the mass and energy balances on the membrane sides. The theoretical model was validated with available data and was found in good agreement. DCMD configuration provided the highest pure water production while SGMD shows the highest thermal efficiency. Process parameters' impact on each configuration are also presented and discussed.

• Membrane and Water Treatment
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• v.5 no.3
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• pp.221-233
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• 2014

Simulations were conducted to predict supersaturation along Reverse Osmosis (RO) modules for seawater desalination. The modeling approach is based on the use of conservation principles and chemical equilibria equations along RO modules. Full Pitzer ion interactive forces model for concentrated solutions was implement to calculate activity coefficients. An average rejection rate for all ionic species was considered. Supersaturation has been used to assess scaling. Supersaturations with respect to all calcium carbonate forms and calcium sulfate were calculated up to 50% recovery rate in seawater RO desalination. The results for four different seawater qualities are shown. The predictions were in a good agreement with the experimental results.

• Natural Product Sciences
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• v.27 no.4
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• pp.280-283
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• 2021

Cercidiphyllum japonicum is being used for the treatment of obesity and liver fibrosis in Korean local clinics. In the present study, we tried to develop an analytical methodology for the determination of the chemical markers of Cercidiphyllum japonicum. Four chemicals, maltol (1), chlorogenic acid (2), quercetin (3), and avicularin (4), were selected for method validation, and the analytical conditions were optimized and validated using high-performance liquid chromatography coupled with an ultraviolet detector (HPLC-UV). Additionally, the seasonal variations of four markers were monitored every month for six months. The contents of four chemicals markers were most detected in a sample collected in June.

• Journal of Korean Society on Water Environment
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• v.37 no.2
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• pp.128-136
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• 2021

It is generally known that a wastewater treatment plant (WWTP) consumes immense energy even if it can produce energy. With an aim to increase the energy independence rate of WWTP from 3.5% in 2010 to 50% in 2030, the Korean government has invested enormous research funds. In this study, cost-effective operating alternatives were investigated by analyzing the energy efficiency and economic feasibility for biogas and power generation using new and renewable energy. Based on the US EPA Energy Conservation Measures and Korea ESCO projects, energy production and independence rate were also analyzed. The main energy consumption equipment in WWTP is the blower for aeration, discharge pump for effluent, and pump for influent. Considering the processes of WWTP, the specific energy consumption rate of the process using media and MBR was the lowest (0.549 kWh/㎥) and the highest (1.427 kWh/㎥), respectively. Energy-saving by enhancing anaerobic digester efficiency was turned out to be efficient when in conjunction with stable wastewater treatment. The result of economic analysis (B/C ratio) was 2.5 for digestive gas power generation, 0.86 for small hydropower, 0.49 for solar energy, and 0.15 for wind energy, respectively. Furthermore, it was observed that the energy independence rate could be enhanced by installing energy production facilities such as solar and small hydropower and reducing energy consumption via the replacement of high-efficiency operating.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.3
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• pp.1-8
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• 2017

The present study aimed to investigate the effect of calcium chloride($CaCl_2$) on the growth and physiological responses of Pinus strobus and the variables that are sensitive to $CaCl_2$. Thus, changes in the visible damage, growth of root collar diameter, plant water content, chlorophyll content and composition, maximum PS II photochemical efficiency, and electron transport rate of P. strobus was analyzed in relation to treatment witih $CaCl_2$. A $CaCl_2$ solution(0.5, 1.0 and 3.0%) was applied in the root zone before leaf unfolding. Leaf browning, defoliation, and drying were observed with $CaCl_2$ application and this pattern was aggravated as the $CaCl_2$ concentration increased and the treatment period became longer. The decrease of growth in root collar diameter and height and leaf water content were observed at $CaCl_2$ 1.0% and 3.0%. The total chlorophyll content indicated that photopigment, PS II photochemical efficiency and electron transport rate significantly decreased at $CaCl_2$ 3.0%. In conclusion, $CaCl_2$ affected leaf water content and led to a decrease of capability in light harvesting and photochemical responses. Also, as a result of the correlation between calcium chloride concentration and growth and physiological response parameters, it was found that the leaf moisture content and the ratio of chlorophyll a and b reflect the damage level of calcium chloride sensitively because their coefficient of determinations were relatively high.

• Conservation Science in Museum
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• v.23
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• pp.1-16
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• 2020

In this paper, Gilt-bronze Standing Avaolkiteshvara (National Treasure No. 293, M355) excavated at Gyuam-ri in Buyeo was observed with a microscope to identify the production technique applied to it. It was also analyzed with XRF and hard X-ray to identify the composition and the surface treatment techniques and casting method applied. In this statue, Avalokiteshvara is standing upright on a lotus pedestal. The lotus designs on the pedestal and those on the shawl flowing down on both sides of the statue are characteristic of Buddhist statues from the seventh century or later. The use of supports to affix the outer and inner molds and traces of injected cast were observed in the interior of the pedestal. The blisters on the arms and pedestal created during the bronze casting indicate the use of lost-wax casting, which was popularly employed for the production of mid- or small-sized gilt-bronze Buddhist statues in ancient times. The composition analysis identified a copper-tin-lead ternary alloy in the interior of the statue that was conventional used in the sixth and seventh centuries. It is likely that this simple alloy was used to facilitate casting and produce clearer expressions of designs and ornaments on the statue. Mercury (Hg) was detected on the surface of the statue, indicating the use of amalgam-plating with gold (Au) dissolved in mercury. This plating method is a common surface treatment technique used for small gilt-bronze statutes in ancient Korea.

• Korean Journal of Plant Resources
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• v.34 no.5
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• pp.470-477
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• 2021

Amsonia ellipotica (Thumb.) Roem. & Schult. has less than 10 native places nationwide and is evaluated as an endangered species (EN) on the Korean Red List, so systematic breeding and cultivation methods are required. This study was carried out to establish an effective method for seedling production in A. elliopotica that can be developed as a genetic resource conservation and new ornamental material. This experiment was performed by varying the seedling production container (72, 105 and 128 cell trays), number of seeds sown in a cell (1, 2, and 4 per cell), soil type [horticultural soil and neutralized peat-moss: perlite mixed in 3:1, 4:1 (v:v)], additional fertilizer concentrations (0, 250, 500 and 1000 mg/L) and shading degrees (0, 55 and 75%). As a result of the study, growth increased with the increased in measuring capacity per cell of sowing container. According to number of seeding growth, sowing one seed per cell was the best. Seedling growth increased as the treatment concentrations increased, higher growth was in 1000 mg/L. On the other hand, during the shading treatment, growth significantly decreased regardless of shading degrees.

• Journal of Korean Society on Water Environment
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• v.26 no.3
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• pp.387-398
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• 2010

SWAT model would be applied to evaluate the pollutant removal capacity with various best management practices (BMPs) in Kyongan stream watershed which plays an important role in water quality conservation and improvement of Paldang reservoir. The methods for the representation of various BMPs scenarios with SWAT is developed and evaluated. Riparian buffer strip, agricultural conservation practices to reduce fertilizer, sediment, and nutrients occurring from farm field (Grassed swale, Contour farming/Parallel terrace, Field border, Farm retention pond, Grade stabilization structure), and washland such as wetland and pond to extend detention and improve water quality are represented in SWAT. And to represent the expansion of existing Waste Water Treatment Plants (WWTPs) in Soil and Water Assessment Tool (SWAT), reduction effect for point source pollutants was simulated. As the result of simulation, the removal rates of SS, TN, TP from scenarios of Kyongan stream watershed are the average annual SS yield by 5.2% to 69.2%, the average annual TN yield by 0.5% to 26.3%, and the average annual TP yield by 1.3% to 32.5%, respectively. This study has demonstrated that the SWAT is a very reliable and useful water quality and quantity assessment tool, and the BMPs representation in SWAT for watershed management is able to effectively simulate in Kyongan Stream watershed.