• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.123-124
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• 2011

플라즈마 화학적 기상 증착(plasma enhanced chemical vapor deposition)공정 중 NH3 gas flow rate, RF power, SiH4 gas flow rate을 고정시키고 N2O gas flow rate을 0 sccm부터 250 sccm까지 변화시키는 조건 하에 SiON박막을 증착한 후 그 투과율, 굴절률을 측정하고 분석하였다. N2O gas flow rate조건별 시편들은 증착율을 계산하여 350 nm 두께로 동일하게 SiON을 증착하였고, borofloat위에 SiON을 증착한 샘플은 투과율을, 실리콘기판 위에 SiON을 증착한 샘플로는 굴절률을 측정하였다. 투과율의 경우는 UV/Vis spectrometer를 이용해 633 nm, 1550 nm 두 가지 파장 대 모두에서 N2O gas flow rate이 가장 큰 250 sccm일 때 가장 높은 것을 알 수 있었고 N2O gas flow rate이 낮아질수록 투과율 또한 작아지는 경향을 보였다. 굴절률은 ellipsometer를 이용해 측정하였으며 633 nm 파장에서 N2O gas flow rate가 가장 낮은 0 sccm일 때 굴절률이 가장 큰 값을 가지고 N2O gas flow rate이 커질수록 굴절률은 지수함수적으로 감소되었다(n=1.837~1.494). 이는 N2O gas flow rate이 낮을수록 SiN계열에 커질수록 SiO2계열에 가까워지는 현상으로 이해된다. 이러한 실험분석 결과는 향후 실리카 도파로의 설계 및 최적화를 위해 사용될 수 있다.

• 약학회지
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• 제39권5호
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• pp.480-486
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• 1995

The change in discharge current of a glow discharge has been shown the potential sensitive detector for gas chromatography. To investigate the effect of carrier gas on the electrical characteristics of the discharge and the peak response, the discharge pressure, gas flow rate, and discharge gap have been studied. The discharge gas included the Ar, He, and N$_{2}$. The gas flow rate has been found one of the important parameters to affect both the electrical characteristics and the peak response.

• 한국가스학회지
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• 제19권3호
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• pp.54-59
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• 2015

가스하이드레이트(GH: Gas Hydrate)는 전 세계적으로 약 10조 톤에 이르는 엄청난 양이 대부분 해양의 대륙사면에 부존되어 있으나(동토 지역 : 2 %, 해양 대륙사면 98 %), 현재까지 가스하이드레이트 저류층으로부터 상업화할 수 있을 만큼 가스를 회수하는 기술이 개발되어 있지 않은 실정이다. 일반적으로 회수하는 방법은 감압법, 열자극법, 억제재 주입법 및 치환법 등으로 크게 나누어 볼 수 있으며, 본 연구에서는 가스하이드레이트 포화율과 감압률에 따라서 가스하이드레이트 해리시간 및 가스생산이 어떻게 달라지는 지, 그에 대한 특성을 분석하고자 하였다. 연구분석 결과 감압률과 해리시간의 상관 관계식을 도출($Y=0.0004X^2-0.499X+176.86$)할 수 있었고, 또한 감압률이 클수록 메탄생산량이 좋다는 것을 알 수 있었지만(감압률 40% 대비 50%에서 메탄가스생산량이 46.2% 향상), 감압률이 60%에서는 오히려 생산량이 줄어드는데, 이는 가스하이드레이트 재형성에 기인한 것으로 판단된다.

• 한국공작기계학회논문집
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• 제17권4호
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• pp.89-94
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• 2008

Differential pressure flow meters which have a shape of triangular separate bar(TSB) were tested for investigating the flow rate characteristics of the flow meters with varying the temperature of the gas flow. Three kinds of the triangular separate bar flow meters whose aerodynamic angles are different one another are used. The mass flow rate of the flow meters are evaluated using a non-dimensional parameter which includes the gas temperature, exhaust gas pressure and differential pressure at the flow meters, and atmospheric pressure. A burner system which is similar to gas turbine was used for raising the gas flow temperature. The burner system was operated with varying the air/fuel ratio by controlling both the fuel injection rate from the fuel nozzle and air flow rate from a blower. An empirical correlation between the mass flow rate at the TSB flow meter and the non-dimensional parameter was obtained. The empirical correlation showed linear relationship between the mass flow rate and the non-dimensional parameter H. Also, the mass flow rate characteristics at the TSB flow meter was affected by the gas temperature.

• 한국연소학회:학술대회논문집
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• 한국연소학회 1999년도 제19회 KOSCO SYMPOSIUM 논문집
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• pp.129-138
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• 1999

In this paper, our main issue is that establishing the control procedure of continuous gas flow rate according to combustion fan RPM. For this, first, we decide the optimum operating condition of gas swirl burner through analysis of combustion characteristics - thermal efficiency, combustion efficiency and exhaust gases such as CO, $CO_{2}$, $O_{2}$, $NO_{x}$ and THC. Second, fuel gas flow rate of gas valve is decided with considering excess air ratio and combustion fan RPM is decided by the target of combustion air flow rate. Finally, experimental operating equation is acquired by regression for gas valve and combustion fan. This equation is the control equation of continuous gas flow rate and always gas flow rate is decided by combustion fan operating RPM.

• 한국환경과학회지
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• 제27권8호
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• pp.621-629
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• 2018

Many chemically active species such as ${\cdot}H$, ${\cdot}OH$, $O_3$, $H_2O_2$, hydrated $e^-$, as well as ultraviolet rays, are produced by Dielectric Barrier Discharge (DBD) plasma in water and are widely use to remove non-biodegradable materials and deactivate microorganisms. As the plasma gas containing chemically active species that is generated from the plasma reaction has a short lifetime and low solubility in water, increasing the dissolution rate of this gas is an important challenge. To this end, the plasma gas and water within reactor were mixed using the air-automizing nozzle, and then, water-gas mixture was injected into water. The dissolving effect of plasma gas was indirectly confirmed by measuring the RNO (N-Dimethyl-4-nitrosoaniline, indicator of the formation of OH radical) solution. The plasma system consisted of an oxygen generator, a high-voltage power supply, a plasma generator and a liquid-gas mixing reactor. Experiments were conducted to examine the effects of location of air-automizing nozzle, flow rate of plasma gas, water circulation rate, and high-voltage on RNO degradation. The experimental results showed that the RNO removal efficiency of the air-automizing nozzle is 29.8% higher than the conventional diffuser. The nozzle position from water surface was not considered to be a major factor in the design and operation of the plasma reactor. The plasma gas flow rate and water circulation rate with the highest RNO removal rate were 3.5 L/min and 1.5 L/min, respectively. The ratio of the plasma gas flow rate to the water circulation rate for obtaining an RNO removal rate of over 95% was 1.67 ~ 4.00.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 2000년도 THE THIRD INTERNATIONAL CONFERENCE ON AGRICULTURAL MACHINERY ENGINEERING. V.III
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• pp.662-669
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• 2000

Based on the viscous flow characteristics of gas through capillary tube, a simple and low cost system was developed for controlling gas concentration for use in C.A experiments. The gas flow rate through capillary tube had a linear relationship with pressure, $(length)^{-1}$ and $(radius)^4$ of capillary tube, which agreed well with Hagen-Poiseuille's law. The developed system could control the gas concentration in storage chamber within ${\pm}0.3%$ deviation compared to the preset concentration. The required time for producing target gas concentration in storage chamber was exactly predicted by the model used in this study, and it required much longer time than the calculated time which divided the volume of chamber by flow rate. Therefore, for producing target gas concentration as quickly as possible, it needs to supply higher flow rate of gas during the initial stage of experiment when gas concentration in storage chamber has not reached at target value. It appeared that the developed system was very useful for C.A experiments. Because one could decide a desired flow rate by the prediction model, control flow rate freely and easily by changing pressure in the pressure-regulating chamber and the accuracy was high.

• Asian Journal of Atmospheric Environment
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• 제2권2호
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• pp.116-124
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• 2008

In this study, the Tier 2 method recommended by the Intergovernmental Panel on Climate Change (IPCC) was used to predict the methane generation rate at two landfill sites, designated as Y and C for purposes of this study, in South Korea. Factors such as the average annual waste disposal, methane emissions ($L_0$) and methane gas generation rate constant (k) were estimated by analyses of waste and the historical data for the landfills. The value of k was estimated by field experiments and then the changes in the methane generation rate were predicted through the year 2050, based on the value of k. The Y landfill site, which was in operation until the year 2008, will generate a total of 17, 198.7 tons by the end of 2018, according to our estimations. At the C landfill site, which will not be closed until the end of 2011, the amount of methane gas generated in 2011 will be 3,316 tons and the total amount of gas generated by 2029 will be 61,200 tons. The total production rate of methane gas at the C landfill is higher than that of the Y landfill. This indicates that the capacity of a landfill site affects the production rate of methane gas. However, the interrelation between the generation rate of methane and the value of k is weak. In addition, the generation of methane gas does not cease even when the operations at a landfill site come to a close and the methane gas production rate is at its highest at end of the operating life of a landfill site.

• 한국대기환경학회지
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• 제16권3호
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• pp.257-264
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• 2000

An aftertreatment device which reduce exhaust gas of natural gas vehicle(NGV), NGV catalyst has important meaning as to reduce the exhaust emission. In this study, the characteristics of NGV catalyst were investigated and the effect parameters of NGV catalyst were analyzed and were predicted by changing the various parameters such as temperature, and gas concentration. The conversion efficiency of NGV catalyst converter was also predicted by Pd-loading, mass flow rate and gas composition.

• Nuclear Engineering and Technology
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• 제33권1호
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• pp.83-92
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• 2001

The properties of off-gas generated from vitrification process of ion-exchange resin were characterized. Theoretical composition and flow rate of the off-gas were calculated based on chemical composition of resin and it＇s burning condition inside CCM. The calculated off-gas flow rate was 67.9Nm$^3$/h at the burning rate of 40kg/h. And the composition of off-gas was avaluated as $CO_2$(41.4%), steam(40.0%), $O_2$(13.3%), NO(3.6%), and SO$_2$(1.6%) in order. Then, actual flow rate and composition of off-gas were measured during pilot-scale demonstration tests and the results were compared with theoretical values. The actual flow rate of off-gas was about 1.6 times higher than theoretical one. The difference between theoretical and actual flow rates was caused by the in-leakage of air to the system, and the in-leakage rate was evaluated as 36.3Nm$^3$/h. Because of continuous change in the combustion parameters inside CCM, during demonstration tests, the concentration of toxic gases showed wide fluctuation. However, the concentration of CO, a barometer of incompleteness of combustion inside CCM, was stabilized soon. The result showed quasi-equilibrium state was achieved two hours after feeding of resin.