• KSBB Journal
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• v.28 no.1
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• pp.48-53
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• 2013

Pretreatment of wastepaper using aqueous glycerol was investigated to enhance the enzymatic hydrolysis. The effects of four factors (solid/liquid ratio, glycerol concentration, acid concentration, and reaction time) on the dissolution yield, the removal of cellulose, hemicellulose and lignin, and the enzymatic digestibility were examined at $150^{\circ}C$. The 1/8 of solid/liquid was determined to perform the reaction uniformly, and the 93% of glycerol concentration was found to be a minimum concentration to conduct the reaction under atmospheric pressure. Also, it was found that the acid concentration and reaction time were strongly related to the dissolution yield and the removal of cellulose, hemicellulose and lignin, but moderately to the enzymatic digestibility. At an optimum condition of $150^{\circ}C$, 1 h and 1% acid concentration, 56% and 49% of hemicellulose and lignin, respectively, were removed, while only 4% of cellulose was removed. The enzymatic digestibility at this condition was 86%, meaning that 83% of the glucan present in the initial substrate was converted to glucose. Compared to glycerol with ethylene glycol as a pretreatment solvent, glycerol is much cheaper than ethylene glycol, but ethylene glycol is superior to glycerol in delignification.

• Journal of Environmental Health Sciences
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• v.33 no.3
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• pp.180-183
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• 2007

Over the last century the mercury (Hg) concentration in the environment has been increased by human activities with inputs from sources such as atmospheric deposition, urban runoff, and industrial effluents. Mercury can be transformed to methylmercury (MeHg) in anaerobic conditions by sulfate reducing bacteria (SRB) and sediments are the principal location for MeHg production in aquatic environments. Interest in bioaccumulation of Hg and MeHg into lower trophic levels of benthic and pelagic organisms stems from public health concerns as these organisms provide essential links for higher trophic levels of food chains such as fish and larger invertebrates. Fish consumption is the major exposure route of MeHg to humans. Recently, it was reported that blood samples in Korea showed much higher Hg levels (5-8 times) than those in USA and Germany. Although this brings much attention to Hg research in Korea, there are very few studies on Hg biogeochemical cycling and bioaccumulation in aquatic environments. Given the importance of Hg methylation and MeHg transfer through food chains in aquatic environments, it is imperative that studies should be done in much detail looking at the fate, transport, and bioaccumulation of Hg and MeHg in the environment. Moreover, there should be long-term monitoring plans in Korea to evaluate the environmental and health effects of Hg and MeHg.

• Wind and Structures
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• v.17 no.1
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• pp.1-19
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• 2013

A multiscale finite element method is applied to the Spalart-Allmaras turbulence model based detached-eddy simulation (DES). The multiscale arises from a decomposition of the scalar field into coarse (resolved) and fine (unresolved) scales. It corrects the lack of stability of the standard Galerkin formulation by modeling the scales that cannot be resolved by a given spatial discretization. The stabilization terms appear naturally and the resulting formulation provides effective stabilization in turbulent computations, where reaction-dominated effects strongly influence near-wall predictions. The multiscale DES is applied in the context of high-Reynolds flow over the Commonwealth Advisory Aeronautical Council (CAARC) standard tall building model, for both uniform and turbulent inflows. Time-averaged pressure coefficients on the exterior walls are compared with experiments and it is demonstrated that DES is able to resolve the turbulent features of the flow and accurately predict the surface pressure distributions under atmospheric boundary layer flows.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.11
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• pp.1017-1026
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• 2015

Infrared (IR) target detection is one of the key technologies in Automatic Target Detection/Recognition (ATD/R) for military applications. However, IR sensors have limitations due to the weather sensitivity and atmospheric effects. In recent years, sensor information fusion study is an active research topic to overcome these limitations. SAR sensor is adopted to sensor fusion, because SAR is robust to various weather conditions. In this paper, a Boolean Map Visual Theory-Morphology (BMVT-M) method is proposed to detect targets in SAR and IR images. Moreover, we suggest the IR and SAR image registration and decision level fusion algorithm. The experimental results using OKTAL-SE synthetic images validate the feasibility of sensor fusion-based target detection.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.3
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• pp.586-592
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• 1999

Microwave assisted extraction(MAE) is known as a more environmental friendly process with economic advantages in terms of less time, less solvent, less energy and less wastes than the current time consuming reflux method. It was applied to develop a rapid extraction method for soluble ginseng components that are major materials used for the processing of ginseng products. In a comparative study between pre established MAE(ethanol 60%, power 80 W, process time 4 min$\times$5) and current extraction method(ethanol 80%, temp. 85oC, time 8 hr$\times$5), MAE was more efficient than the current method to obtain an extract yield(soluble solid), but it was insufficient to extract individual ginsenosides, total phenols, reducing components and acidic polysaccharides. MAE with 80% ethanol by 5 times showed, however, that its extraction efficiency on soluble solid, crude saponin, major ginsenosides, and the other components was equal or superior to that of the current method, indicating that ethanol concentration is one of the critical parameters influencing the MAE process. The quality of ginseng extracts from MAE was assured by evaluating the corresponding standards and by comparing TLC and HPLC patterns with the control.

• Journal of Surface Science and Engineering
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• v.29 no.5
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• pp.371-378
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• 1996

An RF inductively coupled plasma (ICP) torch has been developed as a typical thermal plasma generator and reactor. It has been applied to various materials processings such as plasma flash evaporation, thermal plasma CVD, plasma spraying, and plasma waste disposal. The RF ICP reactor has been generally operated under one atmospheric pressure. Lately the characteristics of low pressure RF ICP is attracting a great deal of attention in the field of plasma application. In our researches of RF plasma applications, low pressure RF ICP is mainly used. In many cases, the plasma generated by the ICP torch under low pressure seems to be rather capacitive, but high density ICP can be easily generated by our RF plasma torch with 3 turns coil and a suitable maching circuiit, using 13.56 MHz RF generator. Plasma surface modification (surface hardening by plasma nitriding and plasma carbo-nitriding), plasma synthesis of AIN, and plasma CVD of BN, B-C-N compound and diamond were practiced by using low pressure RF plasma, and the effects of negative and positive bias voltage impression to the substrate on surface modification and CVD were investigated in details. Only a part of the interesting results obtained is reported in this paper.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2004.11a
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• pp.195-200
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• 2004

Carbon dioxide ($CO_2$) and methane (CH$_4$) are two major greenhouse Bases. $CO_2$is a stack gas of many industrial processes and the main product of the hydrocarbon combustion. There is recent research interest on the synthesis gas (syngas) formation from $CO_2$ and CH$_4$, via the following reaction: CH$_4$+$CO_2$longrightarrow 2H$_2$+$CO_2$, in order to reduce the greenhouse effects and to synthesize various chemicals, Preliminary experiments were conducted on the conversion of $CO_2$ and CH$_4$ to syngas by making use of a microwave plasma torch at atmospheric pressure. Conversion rates of $CO_2$and CH$_4$ to hydrogen (H$_2$), carbon monoxide (CO) and higher hydrocarbons were investigated using Gas Chromatography (GC) and Fourier Transform Infrared (FTIR). The experimental data indicate that the main products were H$_2$, CO and small amount of higher hydrocarbons, such as ethylene (C$_2$H$_4$).

• Journal of Energy Engineering
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• v.8 no.4
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• pp.560-566
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• 1999

PDTF (Pressurized drop tube furnace) experiments using variations of temperature, oxygen/coal ratio, steam/coal and pressure with Roto coal (Sub A) were performed in order to investigate the effects of these experimental parameters on global gasification characteristics at elevated pressure. The results shows that the gasification at elevated pressure is more profitable than that at atmospheric pressure considering the carbon conversion and cold gas efficiency. The oxygen/coal ratio at which maximum cold gas efficiency was appeared ranged from 0.5 to 0.7 g/g. only when the temperature is sufficiently high enough, the raise of steam/coal ratio brings improvement of cold gas efficiency. As the pressure increased, the volume of carbon conversion by heterogeneous reaction increased but the volume of carbon conversion by pyrolysis decreased relatively.

• Journal of Astronomy and Space Sciences
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• v.30 no.4
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• pp.321-326
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• 2013

The modulation transfer function (MTF) is a widely used indicator in assessments of remote-sensing image quality. This MTF method is also used to restore information to a standard value to compensate for image degradation caused by atmospheric or satellite jitter effects. In this study, we evaluated MTF values as an image quality indicator for the Geostationary Ocean Color Imager (GOCI). GOCI was launched in 2010 to monitor the ocean and coastal areas of the Korean peninsula. We evaluated in-orbit MTF value based on the GOCI image having a 500-m spatial resolution in the first time. The pulse method was selected to estimate a point spread function (PSF) with an optimal natural target such as a Seamangeum Seawall. Finally, image restoration was performed with a Wiener filter (WF) to calculate the PSF value required for the optimal regularization parameter. After application of the WF to the target image, MTF value is improved 35.06%, and the compensated image shows more sharpness comparing with the original image.

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.3
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• pp.104-117
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• 1998

Rising concern about climate change has evoked interest in the potential for urban vegetation to help reduce the level of atmospheric CO\sub 2\, a major heat-trapping gas. This study quantified the functio of home energy savings and carbon emission reduction by shading, evapotranspiration and windspeed reduction of urban vegetatioin in Chuncheon. Tree and shrub cover averaged approximately 13% in residential land. The effects of shading, evapotranspiration and windspeed reduction annually saved heating energy by 2.2% and cooling energy by 8.8%. The heating and cooling energy savings reduced carbon emissions by 3.0% annually. These avoided emissions equaled the amount of carbon emitted annually from fossil fuel consumption by a population of about 1,230. Carbon emission reduction per residential building was 55kg for detached buildings and 872 kg for multifamily buildings. Urban vegetation annually decreased heating and cooling energy cost by ￦1.1 billions, which were equivalent to annual savings of ￦10,000 savings and carbon emission reduction due to tree plantings in the wrong locations, while windspeed reduction had a great effect. Plantings fo large trees close to the west and east wall of buildings, full tree plantings on the north, and avoidance of shade-tree plantings or selection of solar-friendlytrees on the south were recommended to improve the function of building energy savings and carbon emission reduction by urban vegetation.