• Journal of the Korean Chemical Society
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• v.37 no.5
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• pp.473-476
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• 1993

Dipropargyldiphenylmetane, $C_{19}H_{16}, crystallizes in a monoclinic space group $C2/_c$$ with a = 11304(3), b = 20.799(5), c = 6.622(2)${\AA}$, ${\beta} = 112.8(3)^{\circ}$, Z = 4, V = 1435.3${\AA}^3,\;F(000)\;=\;520,\;D_c\;=\;1.14g{\cdot}cm^{-3}$ and ${\mu}\;=\;0.32\;cm^{-1}$. The structure was solved by direct methods and all non-H atoms were identified in the E-map. The final refinement gave R = 0.055 from 1328 unique observed reflections with I $\geq$ -1.0 $\sigma(I).$ The molecule belongs to the point group $C_2$ of Symmetry by possessing the 2-fold axis which coincides witeh the crystallographic symmetry axis in the unit cell. The linear propargyl moiety is nearly $perpendicular(94.2)^{\circ}$ to the molecular plane of the benzene ring. The internal angle of methane carbon atoms in $108.1(1)^{\circ}$, bonding to the benzene and the propargyl moiety with the bond lengths of 1.530(2) and $1.560(2)\AA$, respectively. The shortest contant between the molecules is $3.538(2)\AA$ between C(9) and C(9) (-x, y, -1/2-z).

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.223.2-223.2
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• 2010

용융탄산염 연료전지(MCFC)는 $650^{\circ}C$에서 작동하는 고온형 연료전지 시스템이다. 이 시스템은 천연가스 등을 개질하여 생산된 수소를 바로 전기로 생산할 수 있는 시스템으로 열효율이 높으며, 현재 대체 발전시스템으로 각광을 받고 있다. MCFC는 개질방식에 따라 내부개질 방식과 외부개질 방식이 있다. 내부개질 방식은 수소를 생산하는 개질기가 스택내부에 장착된 형식으로 천연가스를 스택내부에서 개질하여 바로 전기를 생산하는 방식이다. 이 내부개질반응에 사용되는 촉매로는 알루미나에 담지된 니켈(Ni) 계열촉매이 주로 쓰이고 있다. 또한 내부개질촉매의 형태는 작은 원주형의 촉매형태로 성형되어 사용된다. 이 성형된 촉매의 크기가 바로 내부개질 스택의 크기를 결정하는 중요한 요소이다. 그래서 촉매의 크기는 되도록이면 작게 성형하는 것이 중요하다. 그러나 촉매의 크기가 너무 작으면 촉매를 성형하는데 큰 어려움이 생기게 된다. 본 연구에서는 니켈 촉매를 공침법이 아닌 균일용액침전법을 이용하여 제조하였으며, 이 촉매를 이용하여 지름이 약 2 mm 이하로 촉매를 압출성형하는 방법을 연구하였다. 먼저 요소(urea)를 이용한 균일용액침전법으로 촉매를 제조하였다. 최적의 촉매 합성조건을 살펴보기 위해서, 반응 온도를 80, 85, 90, 95, $100^{\circ}C$로 변화 시키면서 제조된 촉매의 특성을 살펴보았다. 그리고 촉매의 적절한 니켈 양을 알아보기 위해서 니켈의 양을 30, 40, 50, 60, 70 wt%로 변화 시켰으며, 조촉매로 사용되는 MgO 양을 5, 10, 15, 20 wt%로 변화 시켜서 제조된 촉매의 특성을 살펴보았다. 물성을 비교하기 위해서, X-선 회절분석(XRD) 및 TPR, 물리화학흡착을 하였다. 그 결과 침전반응온도가 $80^{\circ}C$에서 촉매가 가장 좋은 물성을 보였으며, 우수한 개질성능을 보였다. 그리고 촉매 활성물질인 니켈의 함량은 50 wt% 정도가 가장 적절한 함량이었으며, MgO의 함량이 15 wt%일 때 가장 우수한 물성과 개질 성능을 보여주었다. 이 촉매들은 공침법으로 제조된 상용촉매와 비교하였을 때, 보다 우수한 물성과 개질성능 보였다. 그래서 이 촉매를 균일침전법을 이용하여 대량으로 제조한 다음 압출성형 방법을 이용하여 촉매를 원주형으로 제조하였다. 먼저 제조된 촉매는 별도의 분쇄작업(볼밀 혹은 제트밀)을 거치지 않아도 입자사이즈가 약 $4{\mu}m$ 수준이 나오도록 촉매 제조조건을 조절 하였다. 그리고 소량의 Methyl cellulose(MC) 바이더와 물만 사용하여 촉매를 혼합한 다음 스크류 압출기를 이용하여 촉매를 성형하였다. 이 촉매는 지름이 약 2 mm 이하로 제조할 수 있었으며, 기계적 강도는 타정기로 성형한 상용촉매보다 우수하였다. 그리고 촉매 성능 또한 상용촉매와 비교하였을 때, 우수한 성능 보였다. MCFC용 내부개질 촉매로 균일용액침전법을 사용한 촉매가 적합하다고 판단되며, 압출성형에도 적합하다고 판단되었다.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.226.1-226.1
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• 2010

본연구에서는 GTL(gas to liquids)공정의 합성가스 생산을 위해 수증기-이산화탄소 복합개질반응(Combined Steam and Carbon dioxide Reforming of Methane, CSCRM)을 수행하였다. CSCRM은 수증기와 이산화탄소의 공급비 조절을 통해 $H_2$/CO비를 2로 맞추기 용이한 장점을 지니고 있어 다른 단일 개질 반응과 달리 합성가스 생산 시 $H_2$/CO 비율을 조절하기 위한 부가적인 공정이 필요하지 않아 경제적인 공정이다. 일반적으로 사용되는 Ni개질촉매는 가격대비 우수한 성능을 보이지만 S/C비가 낮은 CSCRM의 경우 촉매표면의 탄소침적에 의한 비활성화가 야기되는 문제점이 있다. 따라서 본 연구에서는 산소저장능력과 산소전달능력이 우수한 $CeO_2$를 조촉매로 첨가하여 표면에 형성된 코크 제거가 용이하도록 하였다. Ni-Ce/$MgAl_2O_4$촉매는 동시함침법(co-impregnation)으로 제조하였으며, Ni의 함량을 10wt%로 고정한 상태에서 Ce의 함량을 조절하여 Ce/Ni 최적비를 찾고자 하였다. XRD, TPR, BET, $H_2$-Chemisorption과 같은 촉매의 특성분석을 통해 촉매의 비표면적, 환원특성과 Ni입자의 분산도 등을 확인하였다. Ce를 첨가함에 따라 Ce2.5wt%까지는 비표면적이 증가하다가 이후 점차 줄어드는 경향성을 보였다. 또한, $H_2$-Chemisorption 결과 역시 비표면적과 유사한 경향성을 보였는데, Ce5.0wt%까지 Ni 분산도가 증가 하다가 다시 감소하는 것을 확인할 수 있었다. 반응실험은 $H_2O:CO_2:CH_4:N_2$ = 0.8:0.4:1:1의 공급조건에서 수행하였으며, 질소와 수소 환원분위기로 $700^{\circ}C$에서 1시간 환원 후 $650^{\circ}C$에서 $550^{\circ}C$범위로 온도를 떨어뜨려가면서 반응을 수행하였다. Ce를 첨가함에 따라 $CH_4$ 전환율이 증가를 하다가 Ce2.5wt% 이후 감소하는 것을 확인할 수 있었다. 이러한 높은 촉매 활성은 Ce 첨가로 인해 환원특성이 좋아지고 Ni분산도가 증가하여 담체와 강한 상호작용(SMSI)을 형성함으로 탄소침적 저항성 강화에 기인한 것이다.

• 한국산학경영학회:학술대회논문집
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• 2006.06a
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• pp.147-170
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• 2006

Landfill gas is a mixture of methane and carbon dioxide produced by the bacterial decomposition of organic wastes, and it is considered to produce bad smells and pollute the environment. Economic trials and the developments of landfill gas, as an alternative energy resource, become known at the recent years, Resource development of landfill gas, which is managed by Korea up to now, is for the most part generation using gas engine. Medium BTU and High BTU are considered for the power generation as well. Most income of generation using gas engine is selling charge through a power plant. Expecting to manage the power plant for up to 10 years, the analysis based on revenue and expenditure shows when the unit price is 65.2 Won and the operating rate reaches 90%, it is possible to be into the black in 2012 without considering additional financial expense, It was also analyzed that the profit at a unit price of 85 Won under the anticipated rising unit price by the operating rate of 71% is larger than at the operating rate of 90% under limited unit price of 65.2 Won. It means to manage the power plant at a unit price of 65.2 Won and the operating rate must be higher than 90% for economic logicality. If we assume that the operating rate is 90% and it increases the unit price, the unit price must be higher than 85 Won for the management of a power plant. Analysis of changing a unit price, however, might be expected to have a gradual rise of prices. If there is no price rising and additional income related to CDM(Clean Development Mechanism) and emission trading upon Kyoto protocol, the management of a power plant using gas engine will get financial difficulties because of many operating expenses. However, since landfill gas is considered as a worthy energy resource for the guarantee of sustainable development and for the equity between recent generation and future generation, the development of it must be accomplished by the government's additional supporting and efforts under the interest of all stakeholder who are involved.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.473-479
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• 2017

Due to environmental pollution, hazards of the human body, and global warning, changes in the power train of automobiles are intensifying, and the market forelectronic vehicles is rising. Also, in order to meet the stricter emission regulations forautomobiles with internal combustion engines based on fossil fuel, the proportion of after-treatments for vehicles and vessels is increasing gradually. The objective of this study is to investigate the effectsfrom additive ceric oxide ($CeO_2$) loading amounts to improve the methane ($CH_4$) and nitric oxide (NOx) abatement ability of the natural gas oxidation catalysts(NGOC) reducing toxic gases emitted from compressed natural gas (CNG) buses. Three kinds of NGOC were prepared under the following conditions: fresh and $700^{\circ}C$ for 12hr thermal aging, and the reduction performance of toxic gases was evaluated. Fresh $1Pt-3Pd-1Rh-3MgO-6CeO_2/(Al+Z)$ NGOC containing 6wt% $CeO_2$ had the highest dispersivity of palladium (Pd) with high selectivity to $CH_4$ and improved harmful gas reduction performance. The NGOC with 6wt% $CeO_2$ loaded the least decreased in the dispersivity of the noble metal, and showed the highest reduction of harmful gases due to the thermal durability of $CeO_2$.

• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.3
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• pp.99-111
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• 2017

The purpose of this study is to provide a design and operation technical guideline for meeting the appropriate design criteria to bio-gasification facilities treating organic wastes. Based on the results obtained during the field surveys, the overall design and operation guidelines for bio-gasification facilities, monitoring items, cycle and commissioning period were presented. According to the flow of anaerobic digestion process, Various design factors for bio-gasification facilities were proposed in this study. When designing the initial anaerobic digestion capacity, 10 ~ 30% of the treatment capacity was applied considering the discharge characteristics by the incoming organic wastes. At the import storage hopper process, limit concentration of transporting organic wastes was limited to TS 10 % or less, and limit concentration of inhibiting factor was suggested in operation of anaerobic digester. In addition, organic loading rate (OLR) was shown as $1.5{\sim}4.0kgVS_{in}/(m^3{\cdot}day)$ for the combined bio-gasification facilities of animal manure and food wastes. Desulfurization and dehumidification methods of biogas from anaerobic digestor and proper periods of liquifization tank were suggested in design guideline. It is recommended that the operating parameters of the biogasification facilities to be maintained at pH (acid fermentation tank 4.5~6.5, methane fermentation tank 6.0~8.0), temperature variation range within $2^{\circ}C$, management of volatile fatty acid and ammonia concentration less than 3,000 mg/L, respectively.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.8
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• pp.1160-1167
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• 2017

Objective: To assess the effects of proteinate complex zinc (PC-Zn) on growth performance, antioxidative function, trace element concentrations and immune function in weaned piglets. Methods: Three hundred newly weaned barrows ($Duroc{\times}Landrace{\times}Yorkshire$), 28 days of age, were randomly allotted to 3 dietary groups of 5 replicate pens per group for 4 weeks of feeding. Experimental diets were: i) zinc deficient diet (ZnD, 24 mg/kg Zn supplementation from $ZnSO_4$), ii) inorganic Zn diet supplemented with 120 mg/kg of Zn from Zn sulfate ($ZnSO_4$), and iii) organic Zn diet supplemented with 120 mg/kg of Zn from PC-Zn. The body weight of pigs were recorded at the beginning, at the middle and at the end of the experiment, and the amount of feed supplied each day was recorded. Five barrows from each dietary treatment group were selected to be anesthetized and euthanized at the end of the trial to determine the Zn, Cu, Fe, and Mn concentrations, the hepatic metallothionein content, the levels of methane dicarboxylic aldehyde (MDA), Mn, and Cu/Zn superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) in the spleen, the levels of interleukin (IL)-2, IL-4, IL-10, interferon $(IFN)-{\gamma}$, $CD3^+$, $CD4^+$, and $CD8^+$ T lymphocyte. Results: The accumulation of Zn in the spleen, levels of SOD, GSH-Px, IL-4, IL-10, the proportions of $CD3^+$ and $CD4^+$ T lymphocyte, and the ratio of $CD4^+/CD8^+$ T lymphocyte were increased by organic Zn supplementation compared to ZnD, while the levels of MDA, $IFN-{\gamma}$, and proportion of $CD8^+$ T lymphocyte were lowered. Conclusion: These findings indicate that Zn can improve the antioxidant potential and immune functions of weaned piglets.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.8
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• pp.1198-1205
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• 2017

Objective: An experiment was conducted to isolate and identify new methanogens in Korea from an anaerobic digester that uses pig slurry. Methods: An anaerobic digestate sample was collected from an anaerobic digester using pig slurry. Pre-reduced media were used for the growth and isolation of methanogens. Growth temperature range, pH range, NaCl concentration range, substrate utilization, and antibiotic tolerance were investigated to determine the physiological characteristics of isolated methanogens. The isolates were also examined microscopically for their morphology and Gram-stained. Polymerase chain reaction of 16S rRNA and mcrA gene-based amplicons was used for identification purpose. Results: Four strains, designated KOR-3, -4, -5, and -6, were isolated and were non-motile, irregular coccoid, and 0.5 to $1.5{\mu}m$ in diameter. Moreover, the cell walls of isolated strains were Gram-negative. KOR-3 and KOR-4 strains used acetate for methane production but did not use $H_2+CO_2$, formate, or methanol as a growth substrate KOR-5 and KOR-6 strains utilized acetate, methanol, and trimethylamine for methanogenesis but did not use $H_2+CO_2$ or formate as a growth substrate. The optimum temperature and pH for growth of four strains were $39^{\circ}C$ and 6.8 to 7.2, respectively. The optimum concentration of NaCl for growth of KOR-3, KOR-5, and KOR-6 were 1.0% (w/v). The optimum NaCl concentration for KOR-4 was 0.5% (w/v). All of the strains tolerated ampicillin, penicillin G, kanamycin, streptomycin, and tetracycline; however, chloramphenicol inhibited cell growth. Phylogenetic analysis of 16S rRNA and mcrA genes demonstrated that strains KOR-3, -4, -5, and -6 are related to Methanosarcina mazei (M. mazei, 99% sequence similarity). Conclusion: On the basis of physiological and phylogenetic characteristics, strains KOR-3, -4, -5, and -6 are proposed to be new strains within the genus Methanosarcina, named M. mazei KOR-3, -4, -5, and -6.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.320-320
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• 2016

Nanocrystalline Carbon thin films have numerous applications in different areas such as mechanical, biotechnology and optoelectronic devices due to attractive properties like high excellent hardness, low friction coefficient, good chemical inertness, low surface roughness, non-toxic and biocompatibility. In this work, we studied the comparison of pure DC power and pulsed DC power in plasma sputtering process of carbon thin films synthesis. Using a close field unbalanced magnetron sputtering system, films were deposited on glass and Si wafer substrates by varying the power density and pulsed DC frequency variations. The plasma characteristics has been studied using the I-V discharge characteristics and optical emission spectroscopy. The films properties were studied using Raman spectroscopy, Hall effect measurement, contact angle measurement. Through the Raman results, ID/IG ratio was found to be increased by increasing either of DC power density and pulsed DC frequency. Film deposition rate, measured by Alpha step measurement, increased with increasing DC power density and decreased with pulsed DC frequency. The electrical resistivity results show that the resistivity increased with increasing DC power density and pulsed DC frequency. The film surface energy was estimated using the calculated values of contact angle of DI water and di-iodo-methane. Our results exhibit a tailoring of surface energies from 52.69 to $55.42mJ/m^2$ by controlling the plasma parameters.

• Journal of Energy Engineering
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• v.23 no.3
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• pp.125-131
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• 2014

In order to increase landfill gas (LFG) production with food waste leachate, this study was confirmed to be acidogenetic conditions for landfill site injection. Thereby, it was conducted for acidogenetic treatments to determine the decrease in viscosity and VFA production. After acidogenesis treatments, solubility of food waste leachate increased approximately 15%, and as a result, UASB and CSTR were similar by reactor type using the change of retention time. Based on the result of the change in viscosity by reactor type, efficiency of UASB showed approximately 11.38% of higher decrease in viscosity as $76.95{\pm}3.27%$ vs. CSTR. Also, VFA production showed the higher increase of 2.01 times (UASB) and 1.76 times (CSTR) respectively at the point of increasing retention time from 3 to 5 days. From the above results, efficiency of UASB in a reactor was relatively higher because large molecular lead to longer retention time than small molecular due to having screen effect in the fixed media.