• 대한전기학회논문지
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• 제45권4호
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• pp.501-510
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• 1996

The gas-turbine generator of Seo-Incheon combined-cycle plant was tested for derivation of a model for dynamic analysis. Load rejection and AVR step test was performed to get the dynamic response of generator. The parameters of generator/control system model were determined by these measured data. No-load saturation test was performed for the saturation characteristics of the generator under steady state. V-curve test was also performed so as to find exact generator parameters. Q-axis parameters of generator was derived by measuring power angle. AVR and governor constants have been tuned by their oscillatory period and setting time characteristics. The derived parameters of generator control system is verified by one-machine infinite bus system simulation. (author). 7 refs., 20 figs., 5 tabs.

• 상하수도학회지
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• 제12권1호
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• pp.62-69
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• 1998

To remove nitrogen from wastewater, ammonia nitrogen has to be oxidized to nitrate nitrogen before denitrification reaction which converts nitrate nitrogen to nitrogen gas. In order to understand nitrification, several mathematical models had been proposed and Monod type model has been accepted internationally. Since Monod type model consists of maximum substrate utilization rate, substrate concentration and half-saturation coefficient, these values have to be addressed before using Monod type model. Several experimental procedures to determine half-saturation coefficient have been developed, however, Infinite dilution method was known to be time saving procedure. In this study, the mathematical equations and experimantal procedures for Infinite dilution method are presented and this method is used to determine half-Saturation coefficient for nitrifying bacteria. As results, Infinite dilution method is proved that this coefficient can be determined within 8 hours and the values of half-saturation coefficient has a range of 0.728 and $0.455gNH_4{^+}-N/m^3$ and the average has $0.580gNH_4{^+}-N/m^3$ through 5 sets of experiments.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.519-523
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• 2007

Gas(or methane) hydrates are solid solutions when water molecules are linked through hydrogen bonding and create host lattice cavities that can enclose a large variety of guest gas molecules. The natural gas hydrate crystal may exist at low temperature above the normal freezing point of water and high pressure greater than about 30 bars. A lot of quantities of natural gas hydrates exists in the earth and many production schemes are being studied. In the present investigation, depressurization method was considered to predict the production of gas and the simulation of the two phase flow - gas and water - in porous media is being carried out. The simulation show about the fluid flow in porous media have a variety of applications in industry. Results provide the appearance of gas and water production, the pressure profile, the saturation of gas/ water/ hydrates profiles and the location of the pressure front.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 추계학술대회논문집B
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• pp.241-246
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• 2000

Gas hydrates are solid solutions when water molecules are linked through hydrogen bondin create host lattice cavities that can enclose a large variety of guest gas molecules. The natural hydrate crystal may exist at low temperature above the normal freezing point of water and pressure greater than about 30 bars. A lot of quantities of natural gas hydrates exists in the ear many production schemes are being studied. In the present investigation, depressurization method considered to predict the production of gas and the simulation of the two phase flow - gas and - in porous media is being carried out. The simulation show about the fluid flow in porous have a variety of applications in industry. Results provide the appearance of gas and water prod the pressure profile, the saturation of gas/ water/ hydrates profiles and the location of the pl front.

• 한국광학회지
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• 제1권2호
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• pp.162-168
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• 1990

내경이 2.1mm인 Pyrex 모세관을 사용하여 길이가 150mm인 도파형 이산화탄소 레이저를 제작하였으며, 공진기내에 임의의 손실을 가할 수 있는 ZnSe 손실판을 설치하여 공진기의 내부손실에 따른 출력변화를 여러 방전조건에 대해 측정하였다. 본 실험에 Rigrod 이론을 적용하여 내부손실에 따른 출력변화를 예측했으며 실험치로부터 포화출력 및 불포화 이득계수를 구할 수 있었다. 방전전류와 혼합기체의 유입률이 증가함에 따라 포화출력은 증가하며, 불포화 이득계수는 감소하는 경향을 볼 수 있었다.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.852-857
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• 2017

In this paper, measurements of ion mobility were performed in oxygen at gas pressures of 44.52 - 101.19 kPa using the drift tube method. Over this pressure range, mobility values were within the limits of 1.796 to $3.821cm^2{\cdot}V^{-1}{\cdot}s^{-1}$ were determined and ion mobility shown to decrease non-linearly with increasing gas pressure towards a certain level of saturation. Ion mobility measured in air was lower than that measured in oxygen at the same gas pressure. Finally, a parameter correction method for calibrating the relationship between the ion mobility and gas pressure in oxygen was proposed.

• Korean Chemical Engineering Research
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• 제50권3호
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• pp.556-561
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• 2012

본 연구에서는 고분자형 연료전지(PEMFC) 내의 기체확산층(GDL)에서의 물질 거동 전산해석을 통하여 GDL 물성이 전지성능에 미치는 영향을 알아보았다. GDL 내에서 기상의 산소와 액상의 물의 거동을 계산하기 위하여 multi-phase mixture($M^2$) 모델을 사용하였다. GDL의 접촉각, 기공도, 기체투과도, 두께에 변화를 주며 계산을 실시하여 GDL 내에서의 물질 거동의 변화를 확인 하였고, GDL 물성이 전지성능에 미치는 영향을 파악하였다. 전산해석 결과, GDL의 접촉각과 기공도가 커지고, 두께가 얇아짐에 따라 물질전달 저항이 감소하여 GDL과 촉매층 사이의 계면에서의 물포화도가 낮아지고 산소농도는 증가하여 전지성능이 향상되는 것을 확인하였다.

• 한국어병학회지
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• 제34권2호
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• pp.255-259
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• 2021

This is the first report describing acute mass mortality occurred in juvenile olive flounder (Paralichthys olivaceus) caused by gas bubble disease (GBD). A total of 610 fish (average weight = 35 g), which were more than half of the fish acclimated at 17℃ in an aquarium, were killed within two days of acclimation. The dead and moribund fish showed excessively opened opercula and mouths, and occasionally, severe exophthalmia. Through microscopic observation, numerous gas emboli were found in the gills of the dead and live fish, while the fish were not infected with any microbial pathogens. The dissolved oxygen (DO) saturation level of the rearing water and seawater nearby the facility reached 145% and 286%, respectively, whereas other water quality parameters (such as salinity, pH, and chemical oxygen demand) were normal. The extreme saturation rate of seawater in the shore nearby seemed to be due to an enormous algal bloom that occurred there. Through molecular identification based on 18S rDNA sequences, the most dominant algal species was most closely related to Ulva californica (99.87% sequence identity) followed by U. prolifera, U. linza, and U. curvata (99.81%). Therefore, it can be concluded that supersaturated seawater due to mass algal bloom caused gas bubble disease in the olive flounder, leading to mass mortality. After technical adjustment, such as increased aeration, lowered water circulation rate, and inlet water filtration using micro-pore carbon filters, the DO level became normal, no further mortality occurred and the status of the fish was stabilized.

• 스마트미디어저널
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• 제11권9호
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• pp.30-38
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• 2022

안전사고의 위험성이 상존하는 작업 현장에서 안전사고 발생 시 신속한 조치를 위해서는 생체 데이터를 실시간으로 파악하는 것이 중요하다. 그 중 혈중산소포화도는 인간이 생명을 유지하는 데 있어서 가장 중요한 요소이므로 작업자의 안전관리를 위한 선제 대응으로 상황에 따라서 실시간 산소포화도 측정과 모니터링이 필요하다. 건강 및 생명 위험 보호복을 착용한 작업자로부터 실시간 생체 신호를 수신하고, 외부 시스템에서 작업자의 위험 상태를 공유 및 분석함으로써 작업자의 현재 상태를 진단하고 작업자에게 발생할 수 있는 응급 상황에 효율적으로 대응할 수 있다. 본 논문에서는 사고 현장에서 응급 상황에 대처하기 위해 보호복 착용자의 유해 가스와 산소포화도 위험도를 실시간 모니터링할 수 있고, 착용자의 활동성과 안전성을 보장할 수 있는 웨어러블 산소포화도 측정 플랫폼 기술을 제안하였다. 추후 제안한 시스템의 결과를 통해 확인한 한계점을 극복하고, 움직임 보정 등 개선된 생체 데이터를 플랫폼에 적용한다면 유해 가스 환경뿐만 아니라 응급 환자를 대상으로 하는 병원이나 가정에서도 활용할 수 있을 것이라 기대한다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 추계학술대회 논문집
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• pp.13-13
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• 2009

본 연구는 MLCC 구성성분의 증발/비등에 의한 저분자물질의 제거가 bar 수축에 미치는 영향도를 평가하기 위해, 압착 bar에서 발생하는 고농도의 out gas를 정량하기 위한 최적 system을 구축하고자 하였다. gas 포집에 범용적으로 사용하는 Purge & Trap sampler 대신 Heating block를 사용하여 gas를 발생시키고 동시에 solvent에 용해시킴으로써 고농도의 시료가 희석될 수 있는 전처리 장치를 디자인하였다. 그 결과 고농도 gas 주입에 의한 장비오염과 peak saturation 문제가 해결되었고, gas phase의 시료를 liquid phase로 상전이 시켜 autosampler를 이용한 정확한 량의 시료 주입이 가능하였다. System의 Gage Linearity와 Bias는 각각 1.7%와 1.3%로 개선이 필요없는 수준의 정확도를 가졌다.