• 한국대기환경학회지
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• 제14권6호
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• pp.599-606
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• 1998

Removal of toluene vapor from airstreams was studied in a biological reactor known as a biofilter. The biofilter was packed porous ceramic inoculated with thickened activated sludge (MLVSS 17,683 mg/L). The lab-scale biofilter was operated for 42 days under various experimental conditions including inlet toluene concentrations and flow rates of the contaminated air streams. Removal efficiency reached up 96.6% after 4 days from start up. Nutrient limitation was proposed as a reason for the decrease in biofilter performence. Biofilter performance decreased substantially, coincident with the buildup of back pressure due to accumulation of excess VSS within the medium bed. Practically, the bed needs to be backwashed when the overall pressure drop is greater than 460.6 Pa at SV (Space Velocity) 100 h-1. Periodic backwashing of the biofilter was necessary for removing excess biomass and attaining stable long -term high removal efficiency The removal efficiency of toluene in the biofilter decreased as the gas velocity and toluene concentration in the inlet gas increased. The maximum elimination capacity of ceramic biofilter could reach up to 444.85 g/m3. hr. When the loading of toluene exceed this critical value, substrate inhibition occurred.

• 해양환경안전학회지
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• 제7권1호
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• pp.15-23
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• 2001

In regulation of IGC code 12.1 mechanical ventilation should be arranged to ensure sufficient air movement through the space to avoid the accumulation of flammable or toxic vapours and ensure a safe working environment, but in no case should the ventilation system have a capacity of less than 30 changes of air per hour baed upon the total volume of the space. In this study, a scaled mode chamber was constructed to investigate the ventilation characteristics and stagnation area in the hood room of LNG carrier and pump room in tanker. An experimental study was performed on the model by using visualization equipment with a laser apparatus and an image intensifier CCD camera. Twelve different kinds of measuring areas were selected as the experimental condition. Instant simultaneous velocity vectors in the whole fields were measured by a 2-D PIV system A three-dimensional numerical simulation was also carried out for three different Reynolds numbers. Then the CFD predictions were discussed with the experimental results. The results show the spiral L-shape flow that moves from the opening on the left wall diagonally to the upper right part dominates the ventilation structure. The stationary area of hood room in the velcoity distributions was located in the upper left stern part.

• Asian Pacific Journal of Cancer Prevention
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• 제15권23호
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• pp.10381-10385
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• 2015

SKI-II has been reported as an inhibitor of sphingosine kinase 1 and has been extensively used to prove the involvement of sphingosine kinase and sphingosine-1-phosphate (Sphk1) in cellular processes. In the current study, we investigated the effects of SKI-II and its potential mechanisms in human gastric cancer SGC7901 cells. After treatment with SKI-II, cell growth, cell cycle distribution, apoptosis, expression of Sphk1, NF-${\kappa}B$, Bcl-2, Bax and p27 were assessed by MTT assay, flow cytometry, electron microscopy, immunocytochemistry and Western-blot assay, respectively. Our results showed that SKI-II markedly inhibited SGC7901 cell survival in a dose-dependent manner, reduced cell proliferation with accumulation of cells in the G0/G1 phase and induced apoptosis in the tumor cells. Furthermore, Western blotting and immunocytochemistry showed that the expression of p27 and Bax was increased significantly, but the expression of NF-${\kappa}B$, Bcl-2 and Sphk1 decreased by different degrees. These results indicate that SKI-II induced cell growth arrest and apoptosis. The increased apoptotic sensitivity of SGC7901 was correlated with NF-${\kappa}B$ or Bcl-2/Bax activation.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2006년도 추계학술대회 발표 논문집
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• pp.132-137
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• 2006

With the help of the development of digital-multimedia in the middle of 1990's, FDP(Flat Panel Display) had attracted considerable attention. Collimation proximity exposure system that transfers the pattern on wafer or glass exactly using mask and light with appropriate wavelength is core process in semiconductor and liquid display element. The performances of resolution required in precision exposure system are evaluated by resolving power, depth of focus and storage area. Most of development has targeted on these three factors. The optical design including lamp house has played an important role on the performance of exposure process. In this study, we evaluate the cooling system, concerning on exposure device with mercury lamp among the kernel equipment for the production of LCD, to prevent the instability of lighting due to long term accumulation of excessive heating inside the lamp house. Numerical analysis is conducted on full-scale model. The characteristics of three-dimensional flow, pressure and temperature distribution on exposure system are graphically depicted to estimate the whole cooling system for lamp house and to establish the design criteria.

• 기술혁신연구
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• 제13권2호
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• pp.179-205
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• 2005

This study reveals that the user industry has a limited role in being a source of technological capability in the case of the machine tool industry in Korea where the user industry is relatively more advanced than other capital goods industries. This study examines the sources of technological capability in terms of migration of workforces and flow of product development knowledge. Although the capital goods sector is generally regarded as being the sector where user-producer interaction is important, the user industry is not the seed-bed of technological capability for machine development. Users and producers interact in terms of expressing 'needs', mainly in the form of specifications. As a result of receiving unique specifications from users, the producer learns to react by making specific customised special purpose machines. The user's specification could include information o the imported machine originally used. When confronted with technical problems in developing a new machine, the producer accesses foreign sources of knowledge. This study's finding reveals that users of special purpose machines have a significantly clearer role in providing specifications than do users of general purpose machine tools. Most intensive interactive learning between users and producers in the production process is found in special purpose machine tools. From the empirical findings, policy implications are discussed.

• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8313-8319
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• 2016

We have recently shown that thymoquinone (TQ) has a potent cytotoxic effect and induces apoptosis via caspase-3 activation with down-regulation of XIAP in mouse neuroblastoma (Neuro-2a) cells. Interestingly, our results showed that TQ was significantly more cytotoxic towards Neuro-2a cells when compared with primary normal neuronal cells. In this study, the effects of TQ on cell-cycle regulation and the mechanisms that contribute to this effect were investigated using Neuro-2a cells. Cell-cycle analysis performed by flow cytometry revealed cell-cycle arrest at G2/M phase and a significant increase in the accumulation of TQ-treated cells at sub-G1 phase, indicating induction of apoptosis by the compound. Moreover, TQ increased the expression of p53, p21 mRNA and protein levels, whereas it decreased the protein expression of PCNA, cyclin B1 and Cdc2 in a dose-dependent manner. Our finding suggests that TQ could suppress cell growth and cell survival via arresting the cell-cycle in the G2/M phase and inducing apoptosis of neuroblastoma cells.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2004년도 춘계학술발표회
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• pp.938-945
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• 2004

In order to cope with ever growing traffic flow and complexity in the urban area, construction demands for expanding and realigning of existing urban roads and massive development of underground space within the urban area are in its increasing trend, it is fact that, mainly due to lack of statistical data accumulation through real construction, technology and construction practice to support such demands can hardly be said to have been established enough and leave many things still to be developed. These circumstances therefore came to motivate me to get into a study for a particular subject of "Design Basics for Closely Neighbored Twin Tunnel" among others, and also to put forward subjects required to be further studied in this connection in the future as follows: 1) To make a new economical design model for closely neighbored twin tunnel not only to make a drain for center perfect but also a tunnel construction safe. 2) Further efforts should be exerted for establishment of general standards for design and construction of various types of large cross-section tunnels including Twin structure.

• 한국수소및신에너지학회논문집
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• 제26권2호
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• pp.136-147
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• 2015

Dead-ended operation of Proton Exchange Membrane Fuel Cell(PEMFC) provides the simplification of fuel cell systems to reduce fuel consumption and weight of fuel cell. However, the water accumulation within the channel prohibits a uniform supply of fuel. Optimization of the purge strategy is required to increase the fuel cell efficiency since fuel and water are removed during the purge process. In this study, we investigated the average voltage output which depends on two interrelated conditions, namely, the supply gas pressure, purging valve open time. In addition, flow visualization was performed to better understand the water build-up on the anode side and cathode side of PEMFC in terms of a variety of the current density. We analyzed the correlation between the purge condition and water flooding.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.91-96
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• 2001

Restoration of contaminated soils to an environmentally acceptable condition is important. One of the newer techniques in soil remediation is a method based on electrokinetic phenomena in soils. The technology uses electricity to affect chemical concentrations and water flow through the pores of soils. An important advantage of electrokinetic soil remediation over other in-situ processes such as soil flushing is the capability of control over the movement of the contaminants. Because the migration of the contaminants is confined by the electric field, there is little dispersion outside the treatment zone. Furthermore, the process is effective for soils with low and variable permeability. In the present study, the distributions of cadmium in the electrokinetic processing of kaolinite under the condition of constant applied voltage are investigated. Cadmium accumulates near the cathode without reducing the diffusion of hydroxide ion into the soil. In keeping the catholyte pH at neutrality, cadmium migrates toward the cathode without any accumulation of cadmium near the cathode and is successfully removed at the cathode reservoir. It was also found that the progress of electrokinetic processing of cadmium could be gasped to a certain extent by monitoring the local voltage and the current density.

• 한국수소및신에너지학회논문집
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• 제21권1호
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• pp.35-41
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• 2010

Water management is an important issue of PEM fuel cell operation. Water is the product of the electrochemical reactions inside fuel cell. If liquid water accumulation becomes excessive in a fuel cell, water columns will clog the gas flow channel. This condition is referred to as flooding. A number of researchers have examined the water removal methods in order to improve the performance. In this paper, a new water removal method that investigates the use of vibro-acoutic methods is presented. Piezo-actuators which are devices to generate the flexural wave are attached at the end of a cathode bipolar plate. Flexural wave is used to impart energy to resting droplets and thus cause movement of the droplets in the direction of the traveling wave.