• Korean Journal of Optics and Photonics
• /
• v.1 no.1
• /
• pp.33-39
• /
• 1990

By developing a computer simulation code for discharge excited KrF excimer laser, we analyzed mainly the effects of buffer gas for the $KrF^*$ formation. the $KrF^*$ relaxation. and the absorption of the laser radiation. The $KrF^*$ formation efficiency were found to be 7.5%, 19% and the $KrF^*$ relaxation kinetic reactions were found to be 45%, 30% at the charging voltage of 30 KV and He. Ne buffer gas. respectively. But the absorption of the 248 nm laser radiation were less than 10% by the buffer gas.er gas.

• Proceedings of the Optical Society of Korea Conference
• /
• 1990.02a
• /
• pp.3-8
• /
• 1990

방전여기 방식의 KrF 엑사이머 레이저의 컴퓨터 시뮬레이션 프로그램을 개발하여 방전중의 KrF 형성, 탈여기 및 흡수채널에서 완충가스의 영향을 이론적으로 해석하였다. 생성효율은 Ne 완충가스에서 He보다 2.2배 정도 높았으며, KrF의 탈여기는 He과 Ne 완충가스에서 각각 50%, 30% 정도의 비율을 차지하였다. 그러나 흡수 과정에서는 완충가스의 영향이 크지 않은 것을 알 수 있었다.

• Environmental and Resource Economics Review
• /
• v.31 no.4
• /
• pp.777-799
• /
• 2022

This study examined the latest EU regulatory strengthening trends for refrigerant gases with very large global warming potential (GWP) and derived implications for carbon neutrality. The European Commission recently unveiled an amendment that significantly strengthens the F-gas Regulation. This study presented the meaning of the main contents related to refrigerants in the amendment by comparing them with the current regulations. The main contents of the amendment include drastically reducing the maximum amount of HFCs that can be placed on the market, strengthening regulations related to HFCs allocation, adding products and equipment that use high GWP refrigerants, adding regulated F-gas and updating the GWP of existing gases, and other stricter regulatory designs. This movement of the EU will affect the policy stance of advanced countries such as the United States and Japan, and Korea's policy will also be further strengthened. Therefore, it will be inevitable for related industries to change to next-generation refrigerant gas. Meanwhile, this study also analyzed the latest policy trends related to per- and polyfluoralkyl substances (PFAS) regulation, which were not noted in previsou studies on refrigerants and F-gas. If PFAS's registration of REACH restricted substances, which are being promoted by five European countries, is made, it will have a very big impact on the industry regarding refrigerant gas. In addition, it will be inevitable to thoroughly review each country's greenhouse gas reduction strategies related to F-gas materials, including refrigerants.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.328-329
• /
• 2012

$SF_6$ gas는 반도체 및 디스플레이 제조공정 중 Dry etch과정에서 널리 사용되는 gas로 자연적으로 존재하는 것이 아닌 사용 목적에 맞춰 인위적으로 제조된 gas이다. 디스플레이 산업에서 $SF_6$ gas가 사용되는 Dry etch 공정은 주로 ${\alpha}$-Si, $Si_3N_4$ 등 Si계열의 박막을 etch하는데 사용된다. 이러한 Si 계열의 박막을 식각하기 위해서는 fluorine, Chlorine 등이 사용된다. fluorine계열의 gas로는 $SF_6$ gas가 대표적이다. 하지만 $SF_6$ gas는 대표적인 온실가스로 지구 온난화의 주범으로 주목받고 있다. 세계적으로 온실가스의 규제에 대한 움직임이 활발하고, 대한민국은 2020년까지 온실가스 감축목표를 '배출전망치(BAU)대비 30% 감축으로' 발표하였다. 따라서 디스플레이 및 반도체 공정에는 GWP (Global warming Potential)에 적용 가능한 대체 가스의 연구가 필요한 상황이다. 온실가스인 $SF_6$를 대체하기 위한 방법으로 GWP가 낮은 $C_3F_6$가스를 이용하여 $Si_3N_4$를 Dry etching 방법인 RIE (Reactive Ion Etching)공정을 한 후 배출되는 가스를 측정하였다. 4인치 P-type 웨이퍼 위에 PECVD (Plasma Enhanced Chemical Vapor Deposition)장비를 이용하여 $Si_3N_4$를 200 nm 증착하였고, Photolithography공정을 통해 Patterning을 한 후 RIE공정을 수행하였다. RIE는 Power : 300 W, Flow rate : 30 sccm, Time : 15 min, Temperature : $15^{\circ}C$, Pressure : Open과 같은 조건으로 공정을 수행하였다. 그리고 SEM (Scanning Electron Microscope)장비를 이용하여 Etching된 단면을 관찰하여 단차를 확인하였다. 또한 Etching 전후 배출가스를 포집하여 GC-MS (Gas Chromatograph-Mass Spectrophotometry)를 측정 및 비교하였다. Etching 전의 경우에는 $N_2$, $O_2$ 등의 가스가 검출되었고, $C_3F_6$ 가스를 이용해 etching 한 후의 경우에는 $C_3F_6$ 계열의 가스가 검출되었다.

• Membrane Journal
• /
• v.23 no.3
• /
• pp.189-203
• /
• 2013

F-gases, gases containing fluorine such as perfluorocarbons (PFCs), sulfurhexafluoride ($SF_6$), nitrogen trifluoride ($NF_3$) are known to have green house effects. Although the net emission rates of gases containing fluorine are much lower than those of $CO_2$, their contribution to global warming cannot be ignored because of their extremely high global warming potential (GWP). F-gases mainly have been used for a variaty of applications in the semiconductor/LCD processes and in the electric power distribution industry of the national key industry. One of practical solutions of controlling the emission rates of F-gases is to reuse by separation and recovery of F-gases of low concentration from the gases mixtures with nitrogen or air. This work investigates some methods for F-gases recovery and separation around the membrane-based process.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• v.y2005m4
• /
• pp.198-202
• /
• 2005

Gas generator is the equipment to produce high enthalpy gas used to generate sufficient power to operate turbine and pump system for propellant feeding in liquid rocket engine. Since the limit in operating temperature is imposed due to turbine blade, the gas generator has to be operated at the temperature far below stoichiometric maintaining fuel rich combustion. In this research, fundamental study was performed to understand the non-equilibrium combustion process with in-house code and CFD-ACE as well.

• Aerospace Engineering and Technology
• /
• v.3 no.2
• /
• pp.81-90
• /
• 2004

This paper describes the results of combustion performance test of fuel-rich gas generator(GG) using LOx and kerosene as propellant at off-design conditions. The chamber pressure is thought to be a function of O/F ratio and total propellant mass flow rate. The test shows that the spatial temperature deviation at the exit of gas generator remains within 7.5K and that the average gas temperature at the exit is a function of propellant O/F ratio. The results of firing test of gas generator at off-design conditions, especially the relation between gas temperature and O/F ratio, can provide useful data for the design of future gas generator and for the development of low-O/F ratio reaction analysis code.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.8 no.2
• /
• pp.10-17
• /
• 2004

The results of the combustion performance tests of gas generator which supplies hot gas into the turbine of turbo-pump for liquid rocket engine and uses LOx and kerosene as propellant are described. The gas generator consists of a injector head with F-O-F impinging injector, a water cooled combustion chamber, a gas torch igniter, a turbulence ring and an instrument ring. The effect of turbulence ring and combustion chamber length on performance of gas generator are investigated. The ignition and combustion at design point are stable and the pressure and gas temperature at gas generator exit meets the target. The turbulence ring installed at middle of chamber effectively mixes hot gas with cold gas and the effect of residence time of hot gas in gas generator on combustion efficiency is small. Test results show that the main parameter controlling the gas temperature at gas generator exit is overall O/F ratio.

• 한국연소학회:학술대회논문집
• /
• 2003.12a
• /
• pp.125-130
• /
• 2003

본 논문에서는 액체로켓엔진에서 터보펌프의 160kW급 터빈을 구동하고, 액체산소와 케로신을 추진제로 사용하는 가스발생기의 설계점 연소성능시험 결과에 대해 논의하였다. 충돌형 F-O-F 인젝터, 물냉각 채널을 가진 연소실, torch ignitor, turbulence ring 그리고 측정 링을 갖는 가스발생기에 대해 기술하였고, 점화, 연소, 종료 등의 시험 cyclogram에 대해 언급하였다. 설계점에서의 연소시험 및 turbulence ring 장착여부, 연소실 길이 변화에 따른 연소시험의 결과들에 대해 기술하였다. 연소시험 결과 가스발생기는 설계점에서 안정된 작동성을 보여주었고, 연소압력 및 온도 등의 성능이 예측치에 근접하는 결과를 보여 주었다. Turbulence ring은 출구에서의 가스온도를 균일하게 분포시켜 효과적인 혼합 장치임을 보여 주었고, 4-6msec 정도에서의 잔류시간에서는 연소효율의 차이가 크지 않음을 알 수 있었다. 가스발생기 출구에서의 온도는 공급되는 추진제의 O/F ratio에 따라 매우 민감하게 반응함을 알 수 있었다.

• Journal of Energy Engineering
• /
• v.16 no.2
• /
• pp.58-63
• /
• 2007

In recent years, the technologies for the production of synthetic fuel from natural gas have been attracting considerable interest because of high oil prices. While oil prices remaining high, GTL (Gas-to-Liquids) technology would provide an attractive option for utilizing gas resources. Furthermore, GTL fuels contain almost zero sulfur and low aromatics and have a very high cetane so that they are estimated to be environmentally friendly diesel fuels able of meeting the advanced fuel specifications of the 21st century. GTL process generally consists of three primary steps: synthesis gas production from natural gas reforming, hydrocarbon production from synthesis gas by Fischer-Tropsch (F-T) synthesis, product upgrading by hydrocracking/hydroisomerization. This paper presents a brief summary of GTL technology and worldwide development trend about it focusing on the reforming of natural gas and the F-T synthesis.