• Journal of Korean Society on Water Environment
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• v.33 no.6
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• pp.670-679
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• 2017

An experiment to study the effect of temperature, light, and dredging on release of nutrients downstream from Gongjicheon in the Uiam reservoir was carried out in the laboratory using sediments from different depths. At various water temperatures, dissolved total nitrogen was not released, but the average nutrient flux of dissolved total phosphorus was increased (0.034 at $15^{\circ}C$, 0.005 at $20^{\circ}C$, 0.154 at $25^{\circ}C$, $0.592mg/m^2/d$ at $30^{\circ}C$). Dissolved total phosphorous was released in controlled darkness. In contrast, in controlled light, the concentrations of dissolved total phosphorous and dissolved total nitrogen in the overlying water steadily decreased during the study period (70 d), because they were continuously consumed by the growth of photosynthetic algae. However, there was no significant relationship between water nutrient concentration, nutrient release, and the depth of the sediment. We concluded that the dredging of sediment would not affect the nutrient release rate of the sediment, because there were no significant differences in the nutrient concentrations released from the sediment. When the sediment was removed from the surface to 20 cm in depth, the nutrients were not transferred to the water body, implying that the sediment removal had little effect on secondary pollution.

• Journal of Climate Change Research
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• v.7 no.4
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• pp.433-442
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• 2016

In this study, we examine future changes in surface radiation associated with cloud amount and aerosol emission over East Asia. Data in this study is HadGEM2-CC (Hadley Centre Global Environmental Model version 2, Carbon Cycle) simulations of the Representative Concentration Pathways (RCPs) 2.6/4.5/8.5. Results show that temperature and precipitation increase with rising of the atmosphere $CO_2$. At the end of $21^{st}$ century (2070~2099) relative to the end of $20^{st}$ century (1981~2005), changes in temperature and precipitation rate are expected to increase by $+1.85^{\circ}C/+6.6%$ for RCP2.6, $+3.09^{\circ}C/+8.5%$ for RCP4.5, $+5.49^{\circ}C/10%$ for RCP8.5. The warming results from increasing Net Down Surface Long Wave Radiation Flux (LW) and Net Down Surface Short Wave Radiation Flux (SW) as well. SW change increases mainly from reduced total Aerosol Optical Depth (AOD) and low-level cloud amount. LW change is associated with increasing of atmospheric $CO_2$ and total cloud amount, since increasing cloud amounts are related to absorb LW radiation and remit the energy toward the surface. The enhancement of precipitation is attributed by increasing of high-level cloud amount. Such climate conditions are favorable for vegetation growth and extension. Expansion of C3 grass and shrub is distinct over East Asia, inducing large latent heat flux increment.

• Journal of the Korean Institute of Telematics and Electronics
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• v.5 no.3
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• pp.31-39
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• 1968

In this paper microwave power propagated through the cold plasma was analyzed and measured with respect to the external magenetic flux density. The d. c discharge plasma was in the rectangular waveguide in which two electrode was inserted, and also the glass diseharge tube inserted in the ractangular wavegside. The direction of microwave pro-pagation, the axis of the discharge tube and external magnetic flux were perpendicular to each other. It showed that the attenuation and absorption of micro wave power propagated in the plasma was increased as the magnetic flux density, the discharge current and the pressure of the gas were increased.

• Proceedings of the Membrane Society of Korea Conference
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• 2001.05a
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• pp.135-138
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• 2001

Acrylic wastewater flux was discussed using modules of ultrafiltration hollow fiber and reverse osmosis spiral wound. The optimum backflushing times of membranes were decided and the degree of fouling was discussed with operating time. Permeate flux was decreased rapidly at 12hrs. Separation processes with ultrafiltration and reverse osmosis membranes were not suitable to remove COD and TDS. The improvement of pretreatment processes was needed.

• Journal of the Korean Ceramic Society
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• v.22 no.6
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• pp.58-70
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• 1985

The bond strength of metal to ceramic sealing in Mo-Mn metallizing was investigated by examining the effects of flux composition in alumina ceramics particle size of molybdenum metal powder wet hydrogen atmosphere and temperature in metallizing. The maximum bond strength was obtained when the glass phase filled almost all the microstructural cavities around the interfacial area with few micropores. Such a favorable microstrcutre waas formed and maximum bond strength was observed between 130$0^{\circ}C$. Also the metal to ceramic bond strength was increased using finer molybdenum metal powder than coarse powder. When content of $SiO_2$ in the flux of alumina ceramics was constant metal to ceramic bond strength was improved with increasing the ratio of CaO to MgO in the flux.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1996.10b
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• pp.113-122
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• 1996

본 연구는 석탄가스화복합발전(IGCC)의 핵심부분이라 할 수 있는 슬래깅 형태의 분류층 가스화기에 원활한 Slagging을 유지하기 위해 Flux addition method와 Coal blending method를 적용하였다. 대상탄으로는 가스화에 적합하다고 알려진 알라스카탄, 대동탄과 비교탄으로 가스화에 부적합하다고 알려진 1종류의 유연탄을 대상으로 기본분석 및 화학적 조성분석, 용융온도를 측정하여 봄으로써 대상탄들의 슬래깅성향을 평가하였다. 대동탄과 알라스카탄에 대해서는 Flux addition method를 적용하고, 비교탄에 대해서는 Coal blending Method를 적용한 후, 140$0^{\circ}C$로 운전되는 가스화기의 효율을 최대화할 수 있는 Flux 첨가비와 blending ratio를 산정하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.274-277
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• 2008

Pohang Wind Energy Research Center (PoWER-C) is developing a 3 MW Radial Flux Permanent Magnet (RFPM) Synchronous Generator for offshore Wind Energy Converter (WEC). The blade rotor rpm is 15.7 and the gear ratio is set to be 92.93. The nominal generator rpm at the rated load is about 1459. Baseline design with surface mounted PM magnets are completed. However, there is some concern about the excessive eddy current heating in the magnets. To alleviate this problem, another design with embedded magnet is going on. With embedded magnets, the generator length should be increased to compensate the increased flux leakage. But the field fluctuation in the magnets due to the slots are greatly reduced. This means less eddy currents and lower magnet operating temperature. In this report, engineering efforts for embedded rotor is presented.

• Journal of the Korean Society of Safety
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• v.23 no.1
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• pp.24-27
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• 2008

The recent fire incident in an elementary school of Chonan city causes the media focus on the fire safety of residential container buildings. In this study, real fire tests were conducted in this kind of buildings. Fire temperature and radiant heat flux were measured, in order to investigate the hazard-reduction effects during the fire emergency of residential container buildings. According to the test results, flash over occur in 10 minutes, peak fire temperature was $935.5^{\circ}C$, peak radiant heat flux was $24.99kW/m^2$ at 8minutes after residential container building fire.

• Journal of Microbiology and Biotechnology
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• v.18 no.2
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• pp.334-337
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• 2008

A tightly regulated gene expression system composed of a single-copy target gene under the control of a lac promoter derivative and lacI gene in a multicopy plasmid is proposed, and its ability to control the flux of a metabolic pathway is demonstrated. A model system to control the flux of acetyl-CoA to acetyl phosphate was constructed by integrating pta, a gene encoding phosphotransacetylase, under a tac promoter into the chromosome of E. coli with a pta-negative background and transforming a multicopy plasmid containing the $lacI^Q$ gene into the strain. The production rate of acetate was shown to be tightly controlled when varying the concentration of the inducer (IPTG) in he model system.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.1-5
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• 2004

This paper describe a control scheme for direct torque control of BLDC Motor. The proposed Luenberger Observer scheme calculate flux errors in order to control the torque and flux more correctly. This proposed control scheme has not the requirement of a separate current regulator and proportional-integral (PI) control of the flux and torque, there by improving transient performance and also has the advantage of less torque ripple in steady state with a fixed switching period. The effect of proposed method has been proven by simulations.