• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2000.11a
• /
• pp.149-150
• /
• 2000

석유화학공정은 석유화학제품의 특성상 유기용제를 많이 사용하고 있기 때문에 국내ㆍ외적으로 휘발성 유기화합물질의 배출원으로 큰 부분을 차지하고 있는 시설이다. 국내에서 석유화학시설은 울산공단, 여천공단 및 대산공단에 밀집되어 있고, '96년 10월 여천공단이 대기보전 특별대책지역으로 지정되어 휘발성유기화합물질 배출저감을 위한 종합대책이 고시되면서부터 많은 회사들이 방지시설을 설치하여 대기질이 꾸준히 향상되어 가고 있다. (중략)

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.29 no.4A
• /
• pp.355-363
• /
• 2009

When water inside the concrete member evaporates by high temperature, the evaporation heat which absorbs surrounding temperature occurs. The rate of increment of the internal temperature in concrete is reduced due to the evaporation heat in spite of continuously increasing external temperature. In this paper, the prediction method of internal temperature of concrete members considering the evaporation heat under the high temperature is presented. Finite element method is employed to facilitate thermal analysis for any position of member. And the thermal characteristics models of high strength concrete affected by high temperature are proposed. To demonstrate the validity of this numerical procedure, the prediction by the proposed algorithm is compared with the test results of other researchers. The proposed algorithm shows a good agreement with the experimental results including the phenomenon that temperature is lost by the evaporation heat.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.676-676
• /
• 2013

무기물 양자점을 광감응 염료로 사용하는 경우 양자점의 사이즈 조절만으로 밴드갭을 조절할 수 있어 광학적 특성 조절이 용이하며, 유기 염료보다 광흡수 능력이 뛰어난 장점을 가진다. 특히 카드뮴 계열의 CdS, CdSe 양자점을 순차적으로 증착하여 사용하는 경우 가시광 전 영역을 효율적으로 흡수, 이용할 수 있어 광전기화학 셀의 광전극으로 사용 시 높은 성능을 기대할 수 있다. 하지만, 카드뮴 계열 양자점의 경우 광전기화학 셀로의 구동에 있어 안정성이 낮은 문제점이 있으며, 이는 양자점에 남아있는 정공이 관여하는 양자점 부식 반응으로 인한 것이다. 본 연구에서는 보다 안정적이면서도 고효율의 광전기화학적 수소생산 시스템을 위해, CdSe/CdS 양자점 감응형 ZnO 나노선 광전극에 IrO2 촉매물질을 증착하였다. CdSe/CdS 양자점이 가시광 전 영역을 흡수하며, ZnO 나노선 구조를 통해 생성된 광전자를 효율적으로 포집하여 높은 광전류 특성을 기대할 수 있다. 나아가 산소생산용 조촉매로 많이 사용하는 $IrO_2$ 촉매 물질의 추가증착을 통해 양자점에서 생긴 정공을 빼 줌으로서 정공이 관여하는 양자점 부식 반응을 방지할 수 있다. 실험결과 촉매물질의 증착 이후 광전류 생성 특성 및 수소생산량이 증가하였으며, 안정성 또한 상당히 향상된 것을 확인할 수 있었다.

• Journal of the Korean GEO-environmental Society
• /
• v.13 no.6
• /
• pp.27-31
• /
• 2012

This study was designed to examine the feasibility of functionalized mesoporous silica as the adsorbent for benzene, toluene, ethylbenzene, and xylene isomers (BTEX) in groundwater. p-Xylene was used as the model compound of BTEX. A series of functionalized mesoporous silica with MCM-41 type of structure was synthesized using a co-condensation method. Monoamine, triamine, nitrile, phenyl, and octyl groups were functionalized to the mesoporous silica structure. Adsorption sites for p-Xylene in a functionalized mesoporous silica were Si-O-Si covalent bond, the surfactant, and the functional group. Octyl-functionalized mesoporous silica with stearyltrimethylammonium chloride as a surfactant showed the highest adsorption ability. The maximum xylene adsorption capacity of the octyl-functionalized mesoporous silica with stearyltrimethylammonium chloride based on Langmuir model was 4.17 mmol/g on $20^{\circ}C$, which was 2.9 times higher than that of MCM-41.

• Korean Journal of Environmental Agriculture
• /
• v.38 no.4
• /
• pp.262-268
• /
• 2019

BACKGROUND: To investigate mineralization characteristics of organic resources in the soil, five materials (rice straw, cow manure sawdust compost, microorganism compost, mixed oil-cake, and amino acid fertilizer) were treated according to the nitrogen content, and an indoor incubation experiment was conducted for 128 days. The results of this analysis were applied to determine the nitrogen mineralization pattern of these organic resources. METHODS AND RESULTS: During the constant temperature incubation period, the nitrogen net mineralization rate of the organic resources was the highest in the amino acid fertilizer with the highest nitrogen content, and the lowest in the rice straw with the lowest nitrogen content. A positive correlation (0.96) was observed between the potential nitrogen mineralization rate and total nitrogen content. The mineralization rate constant, k, was negatively correlated with the organic matter (-0.96) and carbon content (-0.97). The nitrogen mineralization rate during the first cropping season, as estimated by the model, was 6.6%, 11.6%, 30.9%, 70.7%, and 81.0% for the rice straw, the cow manure sawdust compost, the microorganism compost, the mixed oil-cake, and the amino acid fertilizer, respectively. CONCLUSION: The nitrogen mineralization rate varies depending on the type of organic resources or the nitrogen content; thus, it can be used as an index for determining the nitrogen supply characteristics of the organic resource. Organic resources such as compost with low nitrogen content or those undergoing fermentation contain organic nitrogen. Organic nitrogen is stabilized during the composting process. Therefore, as the nitrogen mineralization rate of these resources is lower than that of non-fermented organic resources, it is desirable to use the fermented organic materials only to improve soil physical properties rather than to supply nutrients for the required amount of fertilizer.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.1432-1433
• /
• 2011

본 연구에서는 나노입자 이산화티타늄을 이용한 광전화학셀을 제작하여 제작된 광전기화학셀의 광전변환특성을 연구 하였다. 광전기화학셀을 제작함에 있어 광전극에는 나노입자 이산화티타늄을 페이스트로 하여 스크린 프린팅 하고 열처리 하였으며 상대전극의 경우 $H_2PtCl_6$를 2-propanol에 10mM로 녹인 용액을 도포하였다. 나노 페이스트와 용액처리를 한 광전극과 상대전극을 접합 후, 전해질을 주입 후 밀봉하여 셀을 제작하였다. 이때 사용된 전해질은 LiI, $I_2$, t-butylpyridine, 1-butyl-3-methylimidazolium iodide, 3-methoxypropionitrile이 사용되었다. 제작한 셀의 광전 변환 효율은 개방전압 Voc는 16.3v, 충진율 FF는 0.65로 나타났으며 이때의 변환 효율 7.55%로 나타났다.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2001.11a
• /
• pp.287-288
• /
• 2001

휘발성유기화합물질의 처리기술은 크게 연산화, 촉매산화 및 흡착등의 기술과 비교적 최근에 활발히 연구가 진행되고 있는 바이오필터, 전자빔, 플라즈마, UV 산화, 플라즈마-촉매등의 기술이 있다. 휘발성 유기화합물질의 배출원은 매우 다양하나 국내의 경우 대규모의 도장시설이나 석유화학시설등 대형배출원의 경우에는 거의 대부분 연산화, 촉매산화, 흡착등의 기술이 적용되어 사용하고 있다. 한편, 국내에는 휘발성유기화합물질 규제대상 업종으로 중ㆍ소규모의 배출시설도 많이 있으며 이러한 시설들에 적용하기 위해 현재 여러종류의 새로운 기술들이 연구개발중이다. (중략)

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.33 no.4
• /
• pp.71-78
• /
• 2005

The vaporization characteristics of a liquid heptane droplet in a supercritical nitrogen flow is numerically analyzed. The present model can account for real gas effects, liquid-phase internal circulation, variable thermodynamic properties and high-pressure effects. Time marching method with preconditioning scheme is employed to handle the low Mach number flows in dense heptane droplet region. Computations are made for the wide range of convective velocity and ambient pressure. Numerical results indicate that the droplet deformation becomes stronger by increasing the Reynolds number and it becomes relatively weak by increasing the pressure.

• Journal of the Korean Institute of Gas
• /
• v.23 no.1
• /
• pp.41-46
• /
• 2019

LNG is supplying to consumers as gas phase vaporized by major seawater vaporizer, i.e.. open rack vaporizers. But as soon as the temperature of seawater drops below $5^{\circ}C$ in winter, the submerged evaporators should be operated and cause a lot of energy consumption because of their natural gas combustion. In order to reduce the consumption amount, in this study new two-way supplying method of seawater instead of the present one-way supplying system is introduced and analysed the technical possibilities and economical savings. The results showed that in case of the temperature of seawater becomes below $2.5^{\circ}C$, LNG can be evaporated using ORV without operating S MV. If this system is applied in Incheon LNG terminal, the energy saving reaches 11,770 Ton of LNG as 11,760 million won. By the analysis, the two-way supplying system of seawater in ORV can be the most effective method to be able to save huge amount of energy every year.

• 한국전기화학회:학술대회논문집
• /
• 1999.04a
• /
• pp.16-16
• /
• 1999