• 한국주조공학회지
• /
• 제38권3호
• /
• pp.60-65
• /
• 2018

In the present study, the characteristics of Mg inverter cases for hybrid cars are investigated. Concerns over the use of lightweight materials to reduce energy use and to mitigate emission problems are inevitable in the twenty-first century. Magnesium is a promising material for the manufacturing of lightweight parts. Several cases for thermal cooling channels have been designed and simulated, and the effects of materials and coatings on the thermal cooling efficiency have been discussed. The effects of the coating thickness on heat extraction in an Mg inverter housing case using the PEO (plasma electrolyte oxidation) coating method were also discussed. In order to produce an inverter case by the diecasting process, the filling sequence and cooling behavior during the diecasting process were simulated. The optimized process conditions from the simulation result were then used in a trial diecasting experiment.

• Journal of Photoscience
• /
• 제8권3_4호
• /
• pp.123-126
• /
• 2001

We have attempted to determine the Germanium ion (G $e^{4+}$) effect on the human body by observing the formation of artificial lipid membrane and photolysis in the mineral water containing G $e^{4+}$ ion. The artificial lipid membrane is prepared by using the phospholipid in the Germanium water and the formation efficiency of the liposomes is compared with those obtained in the plain mineral water without G $e^{4+}$ ion. This work shows that the liposomes are formed in the Germanium water better than in the non-Germanium water. The liposomes can be photolyzed by superoxide anion ( $O_{2-}$$^{.}$) produced in the presence of some peptide such as NAT (N-acethyl-L-tryptophan). However, this is inhibited by superoxide dismutase (SOD), and it was found that the activity of SOD on the inhibition of the liposomes oxidative damage is higher in the Germanium water than in the non-Germanium water. It is concluded that the G $e^{4+}$ ion in mineral water helps the formation of new cell as well as elevation of SOD activity for the lipid oxidation.n.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2007년도 추계학술대회 논문집
• /
• pp.1229-1235
• /
• 2007

철도의 토양오염은 크게 총석유계탄화수소(total petroleum hydrocarbon, TPH)에 의한 오염과 중금속류에 의한 오염으로 구분할 수 있다. 이중 TPH 오염은 디젤과 윤활유에 의해서 발생한다. 본 연구에서는 철도 윤활유 유래 오염토양을 정화하기 위해 토양세척방법, 화학적 산화법, 초음파 추출법의 타당성을 연구하였다. 디젤 유래 오염 토양의 토양세척에 많이 사용되는 비이온성 계면활성제는 윤활유 유래 오염 토양의 정화에는 효과적이지 않았다. 다양한 종류의 알코올과 계면활성제를 함께 사용한 경우, 계면활성제만 사용한 경우보다 효과적이었다. 따라서 TPH 오염 철도 토양의 TPH의 오염원에 따라 다른 방법을 적용하는 것이 정화효율을 높일 수 있다.

• 공업화학
• /
• 제28권2호
• /
• pp.165-170
• /
• 2017

나일론의 단량체인 아디픽산을 바이오매스인 갈락토스로부터 얻기 위한 효율적인 합성법을 개발하였다. 백금촉매를 이용한 갈락토스의 산화반응을 통해 얻어진 갈락타릭산으로부터 마이크로웨이브를 이용한 탈산소탈수(DODH)반응을 통하여 30 min의 매우 짧은 반응 시간 안에 97%의 높은 수율로 아디픽산의 주요 중간체인 뮤코네이트를 합성하였다. 생성된 뮤코네이트는 팔라듐 촉매를 이용한 수소화 반응 및 가수분해 반응을 통하여 성공적으로 나일론의 단량체인 고순도의 아디픽산으로 전환되었다.

• 동력기계공학회지
• /
• 제12권5호
• /
• pp.34-39
• /
• 2008

The combustion purpose of diesel engine is to reduce the emission of green gas and to produce high output. Generally, the regulation matter of emission gas is largely diveded by 'THC', 'NOx', 'CO' and 'PM'. Among those matters, the most problem is to disgorge into 'PM', the character of diesel combustion. Diesel PM can be controlled using Diesel Particulate Filter, which can effectively reduce the level of soot emissions to ambient background levels. $NO_2$ generated by the DOC is used to combust the carbon collected in the DPF at low temperature. To certificate DPF device that is suitable to domestic circumstances, it is necessary to exactly evaluate the DPF devices according to the regulation of DPF certificate test procedure fur retrofit. To do carry out the above-mentioned description the understanding of that regulation like the standard of PM reduction is needed. In this study the test procedure including test cycle and BPT test condition was examined, and also the test result for specific DPF was analyzed. In every test like field test, PM reduction efficiency test and Seoul-10 mode test, no defect was showed.

• 상하수도학회지
• /
• 제28권5호
• /
• pp.541-548
• /
• 2014

The pickling brine generated from the salting process of kimchi production is difficult to treat biologically due to very high content of salt. When pickling brine is treated and discharged, it cannot satisfy the criteria for effluent water quality in clean areas, while resources such as the salt to be recycled and the industrial water are wasted. However, sterilization by ozone, UV and photocatalyst is expensive installation costs and operating costs when considering the small kimchi manufacturers. Therefore there is a need to develop economical process. The study was conducted on the sterilization efficiency of the pickling brine using electrochemical processing. The electrochemical treatment of organic matters has advantages over conventional methods such as active carbon absorption process, chemical oxidation, and biological treatment because the response speed is faster and it does not require expensive, harmful oxidizing agents. This study were performed to examine the possibility of electrochemical treatment for the efficient processing of pickling brine and evaluated the performance of residual chlorine for the microbial sterilization.

• 한국수소및신에너지학회논문집
• /
• 제22권4호
• /
• pp.474-480
• /
• 2011

Hydrocarbon is required to be converted to pure hydrogen without carbon monooxide (CO) for polymer exchange membran fuel cell (PEMFC) applications. In this paper, CO cleaning processes as the downstream of Dimethyl ehter (DME) autothermal reforming process were performed in micro-reactors. Our study suggested two kinds of water gas shift (WGS) reaction process: High Temperature shift (HTS) - Low Temperature shift (LTS), Middle temperature shift (MTS). Firstly, using perovskite catalyst for MTS was decreased effieiciency since methanation. Using HTS-LTS the CO concentration was decreased about 2% ($N_2$ & $H_2O$ free) with the reaction temperature of $420^{\circ}C$ and $235^{\circ}C$ for HTS and LTS, respectively. As the final stage of CO cleaning process, preferential oxidation (PROX) was applied. The amount of additional oxygen need 2 times of stoichiometric at $65^{\circ}C$. The total conversion reforming efficiency of 75% was gained.

• Journal of Microbiology and Biotechnology
• /
• 제28권7호
• /
• pp.1141-1146
• /
• 2018

2'-Fucosyllactose (2'-FL) is one of the most important human milk oligosaccharides and has several health benefits for infants. The levels of 2'-FL in breast milk or samples from other sources can be quantified by high-performance liquid chromatography. However, this method cannot be used for simultaneous detection of the target compound in numerous samples. Here, we developed a simple method for quantifying 2'-FL in a microplate format. The method involves two steps: (i) release of $\text\tiny{L}$-fucose from 2'-FL by ${\alpha}$-(1-2,3,4,6)-$\text\tiny{L}$-fucosidase and (ii) measurement of NADPH formed during the oxidation of $\text\tiny{L}$-fucose by $\text\tiny{L}$-fucose dehydrogenase. This method enables measurement of up to 5 g/l 2'-FL in 50 min using a 96-well microplate. The efficiency and simplicity of the proposed method make it suitable for the analyses of a large number of samples simultaneously.

• 한국정밀공학회지
• /
• 제27권12호
• /
• pp.99-106
• /
• 2010

Gas turbines operation for power generation increased rapidly since 1990 due to the high efficiency in combined cycle, relatively low construction cost and low emission. But the operation and maintenance cost for gas turbine is high because the expensive superalloy hot gas path parts should be repaired and replaced periodically This study analyzed the initiation and propagation of the crack at the gas turbine blades which are coated with MCrAIY as a bond coat and TBC as a top coat. The sample blades had been serviced at the actual gas turbines for power generation. Total 7 sets of blades were analyzed and they have different EOH(equivalent operation hour). Blades were sectioned and the cracking distribution were measured and analyzed utilizing SEM(scanning electron microscope) and optical microscope. The blades which had 52,000 EOH of operation had cracks at the substrate and the maximum depth was 0.2 mm. Most of the cracks initiated at the boundary layer between TBC and bond coat and propagated down to the bond coat. Once bond coat is cracked, the base metal is exposed to the oxidation condition and undergoes notch effect. Under this environment, the crack branched at the inter-diffusion layer and propagated to the substrate. Critical cracks affecting the blade life were analyzed as those on suction side and platform.

• 한국물환경학회지
• /
• 제22권5호
• /
• pp.895-904
• /
• 2006

The improved MLE (modified Ludzack-Ettinger) process was operated for piggery waste treatment in full-scale public livestock waste treatment plant. The treated waste from bioreactor was suitable for the strict effluent standard of 200 mgCOD/L and 60 mgTN/L as it was dewatered chemically without settling tank and passed through filtration process. Though this treatment method produced a great deal of sludge ($6.4m^3\;per\;m^3$ dewatered piggery waste) it was able to accomplish predominant effluent quality by removing non-biodegradable COD and color without advanced oxidation process as ozone, fenton and etc.. The nitrogen removal efficiency of bioreactor was rapidly declined from March to May (from 0.016 to 0.005 kgN/kgVSS-day) when disinfection is in earnest as well as from warm season when reactor temperature rises higher than $35^{\circ}C$(from 0.016 to 0.008 kgN/kgVSS-day). This study proves that counterplanes for infection residuals, bioreactor temperature and dewatering sludge reduction are necessary for piggery waste treatment.