• Journal of Life Science
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• v.23 no.11
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• pp.1365-1370
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• 2013

Immobilized cellulase on weak ion exchange resin showed a typical Langmuir adsorption isotherm. Immobilized cellulase had better stability with respect to pH and temperature than free cellulase. Kinetics of thermal inactivation on free and immobilized cellulase followed first order rate, and immobilized cellulase had a longer half-life than free cellulase. The initial rate method was used to characterize the kinetic parameters of free and immobilized enzyme. The Michaelis-Menten constant $K_m$ was higher for the immobilized enzyme than it was for the free enzyme. The effect of the recirculation rate on cellulose degradation was studied in a recycling packed-bed reactor. In a continuous packed-bed reactor, the increasing flow rate of cellulose decreased the conversion efficiency of cellulose at different input lactose concentrations. Continuous operation for five days was conducted to investigate the stability of long term operation. The retained activity of the immobilized enzymes was 48% after seven days of operation.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2009.05a
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• pp.239-241
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• 2009

DRIE(Deep Ion Reactive Etching) 공정은 실리콘 웨이퍼를 식각하는 기술로서 Si wafer 비아 홀 제조에 주로 사용되고 있다. 즉, DRIE 공정은 식각 및 보호층 증착을 반복함으로써 직진성 식각을 가능하게 하는 공정이다. 또한, 3차원 적층 실장에서 Si wafer 비아 홀에 결함없이 효과적으로 구리 충진을 하기 위해서는 직각형 via보다 경사벽을 가진 via가 형상적으로 유리하다. 본 연구에서는 3차원 적층을 위한 Si wafer 비아 홀의 결함 없는 효과적인 구리 충진을 위해, DRIE 공정을 이용하여 기존의 경사벽을 가지는 via 흘 형성 공정보다 더욱 효과적인 공정을 개발하였다.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.518-529
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• 1996

To develope chemical heat pump using available energy sources such as solar heat and many kinds of waste thermal energy we have studied the enhancement effect of inserted fins in cylindical packed bed reactor. Two dimensionnal(radial and circumferential) partial differential eqaetions, concerning heat and masstransfer in CaO packed bad, are solved numerically to describe the characteristics of the reaction of fins inserted reactor and heat transfer. The results obtained by numerical analysis about two dimensional profiles of temperature and conversion in the reactant in the packed bed and exothermic heat amount released from the reactor are follows; -. The insertion of fins in reactor can redue the reaction completion time by half. -. The rate of thermochemical reaction depends of the temperature and concentration and it is also governed by the boundary conditions and heat transfer rate in the particle packed bed.

• Clean Technology
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• v.10 no.3
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• pp.159-168
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• 2004

Benzene adsorption experiment was carried out for activated carbon and zeolite 13X adsorbents. Single column and dual column packed with two adsorbents were used to investigate the dynamic adsorptive characteristics. Effect of feed flow rate on the breakthrough curve was not significant. Specific adsorption amount of benzene for activated carbon was larger than that for zeolite 13X. On the contrary, adsorption amount per column volume was larger for zeolite 13X column because the density of zeolite 13X was larger. In the dynamic experiment using dual adsorbents column, length of mass transfer zone was changed by the feed direction. Breakthrough time was longer and breakthrough curve was sharper when activated carbon was packed in feed inlet and zeolite 13X was packed in column outlet. Also breakthrough time and breakthrough curve slope were affected by the packing ratio of the two adsorbents.

• The Korean Journal of Petroleum Geology
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• v.6 no.1_2 s.7
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• pp.1-7
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• 1998

A multichannel seismic profile from the southwestern margin of the Ulleung Basin, East Sea, was analysed in detail to interpret the middle to late Miocene sequence stratigraphic evolution of the area. A regressive package is overlying a transgressive package which, in turn, is underlain by older uplifted and deformed sedimentary layers. A prominent condensed section separates the regressive and transgressive packages. The transgressive package is characterized by onlapping onto the underlying uplifted and deformed strata. The regressive package contains six prograding sequences composed of seismically resolvable lowstand, highstand, and transgressive systems tracts. Most of the depositional sequences comprise lowstand systems tracts consisting of basin-floor fan, slope fan, and prograding complex. Potential reservoirs in the regressive package are turbidite sands in basin-floor fans, channel-fill sands and overbank sand sheets in slope fans, and incised valley-fill sands in the shelf. The shallow marine sands in transgressive packages are another type of reservoir. Detailed sequence stratigraphic analysis, seismic data reprocessing, and 3-D seismic survey are suggested for the successful hydrocarbon exploration in the study area.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.3
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• pp.53-59
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• 2018

This study analyzed the field applicability through the combination of environment-friendly grid-typed reinforcements and pre-mixed fiber with filler. The film of the grid-typed reinforcement is made by recycled PE resin. And, Ascon fiber is obtained the dispersion by pre-mixing of filler. To be able to recognize in advance the various circumstances that could arise in the construction of the road pavement layer, we conducted a basic field application test of the (Mock Up) pavement layer. As a result, it was found that the pavement with environment-friendly grid-typed reinforcement and dispersive fiber construction had improved strength, stress, and rutting resistance. It is consistent with the strength and stress results of the actual test of the mock up specimen. It is expected to perform an effective role in the safety as well as the use of environment-friendly fibers in actual construction.

• Applied Chemistry for Engineering
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• v.7 no.6
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• pp.1181-1191
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• 1996

To develope chemical heat pump, which is operated by heat of high temperature using available energy sources such as solar heat and many kinds of waste thermal energy we have studied theoretically the enhancement effects of inserted fins on the rate of heat transfer and reaction in cylinderical $Ca(OH)_2$ packed bed reactor. The results obtained by numerical analysis about profiles of temperature, completion time of reaction and exothermic heat amount released from the reactor read as the inserted copper fins in reator reduce the completion time of dehydration reaction in packed bed by half, and the rate of thermochemical reaction depends on the temperature and concentration, and it is also governed by the boundary conditions and the rate of heat transfer in the particle packed bed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.4
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• pp.347-355
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• 2021

During the earthquake, for multi-story structure, if the first floor is soft, the deformation will concentrate on that floor causing a serious damage to the column members which might leads to the collapse of the whole structure like Piloti structure during the Pohang earthquake in Korea. According to the 2016 National Disaster Management Research Institute's "Investigation of Seismic Reinforcement and Cost Analysis of Domestic Non-seismic Buildings", the rate of seismic resistance of private reinforced concrete buildings was 38.3 %. Among them, it was reported that the seismic-resistance ratio of the two to five-story structures was less than 50 %. Accordingly, the government is trying to improve the seismic rate through support projects, but the conventional seismic reinforcement methods are still expensive, and emergency construction is difficult. Therefore, in this study, the field applicability was evaluated by improving the reinforcement method using Velcro, which was developed through the research project of the Ministry of Land, Transport and Maritime Affairs in 2014. In order to improve the performance of the Velcro reinforcement method, introducing the initial tension of Velcro using high foaming rigid urethane filling between the Velcro and concrete of the columns was applied. Additionally, an experiment was conducted to evaluate the ductility of Velcro specimen from the concrete confinement effect. As a result, the ductility of the Velcro specimen was improved compare to Normal specimen. However, the energy dissipation capacity of VELCRO2 is better than VELCRO1, yet the maximum ductility of those two specimens did not show a significant difference. Therefore, the improvement of the internal filler material is still needed to have a better maximum ductility.

• Water for future
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• v.16 no.4
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• pp.245-252
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• 1983

Recently river water pollution in Korea is given rise to serious problem in aspect of crop production, drinking well, water contamination and etc. Under these urgent situations, it is prime importance to protect water resources from pollutants. An environmental isotope survey of the groundwater form the shallow alluvial and the underlying crystalline rock aquifer of the Han River Basin has been undertaken, Analysis of the data has I) confirmed the hypothesis that the groundwater from the metropolitan area is recharged from the river whereas that form the non-urbanized region of the Basin is replenished by the infiltrating precipitation; ii) shown that crystalline rock aquifers are recharged by the ground water form the overlying alluvium. Old groundwater is a group of wells with tritium values in the range of 0 to 2 TU. These low values indicate that the water sampled was recharged much ealier, at least a few decades, than the other groundwater samples of higher tritium content. The low values in this region may, in fact, reflect the effect of the impermeable clay layers which impede infilteration from the surface. Stable isotope evidence confirmed that a recharge in the karst area occurs at a significantly greater elevation than that to the alluvial aquifer. An analysis of the tritium level collected over an annual cycle suggests that the residence time of groundwater is probably not more than a few months. There does not appear to be any correlation between the trace level of Zn, Mn and Pb in the groundwater and the mechanism of the recharge.

• Journal of Korea Soil Environment Society
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• v.3 no.1
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• pp.31-44
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• 1998

The geochemical experiments were carried out to investigate a removal effect of heavy metals in abdndoned metallic mine wastes, and to conceive a treatment techniques of them. In order to prevent contamination, experiment appature was made of acrylic acid resin and polyethylene which resist to acid and alkali. Experiment models are devided into four groups based on the system environments, distribution patterns and a kind of filling materials. The first group is background model(model I ) which is filled with waste only and opened to air. The second one is four layer group which is subdivided into two models, opened and closed systems, and the third mix group which is subdivided into three models based on mixing ratio of filling materials and system environment like a layered group. The forth is composed of two layer model, lower one composed of waste and upper one limestone chips. Solution drained from Model Ishows a high contents of heavy metals on the all terms of experiments. Among the models, however, the closed mix model V and Ⅶ show the most effective removal of heavy metals liberated from wastes. Models having different mixing ratios of filling materials on closed systems does not affect in heavy metal removal effect. But, the distribution patterns of filling materials affect very much on removal effect of heavy metals. The closed models with same constitution ratios and distribution patterns of filling materials show more and less effective removal to the open models.