• 한국동물학회:학술대회논문집
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• 한국동물학회 1999년도 한국생물과학협회 학술발표대회
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• pp.237.1-237
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• 1999

No Abstract, See Full Text

• 통합자연과학논문집
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• 제2권3호
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• pp.219-223
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• 2009

Easy and simple synthesis of CdSe nanocrystals was achieved through sol-gel process. CdSe nanocrystals were synthesized from the reaction of cadmium oxide and selenium in the prescence of trioctylphosphine oxide, tributylphosphine, octadecene, octadecylamine, and stearic acid. The effect of reaction temperature for the determination of size of CdSe nanocrystals was investigated after the addition of selenium. The reaction temperature for the growth of CdSe nanocrystals was increased by every $20^{\circ}C$ from 170 to 190, 210, 230, 250, 270, and $290^{\circ}C$. When the reaction temperature was higher, the absorption wavelength in the absorption spectrum was increased which indicated that the size of CdSe nanocrystals was increased. The emission wavelength in the photoluminescence spectrum was increased from 438 to 489, 542, 591, 643, 692, and 745 nm, as the size of CdSe nanocrystals was increased. The control of the reaction temperature illustrated that the color tuning of emission wavelength were successfully obtained.

• Journal of Ginseng Research
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• 제17권1호
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• pp.35-38
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• 1993

A new and rapid method for the hydrolysis of ginsenosides to panaxadiol or panaxatriol was developed. It is based on the microwave oven reaction, which is high temperature and high-pressure reaction. The optimal hydrolysis time using 5% $H_2SO_4$ solution was found at 10 min PTFE reaction vessel in microwave oven, which is more than 30 times faster than the conventional hydrolysis method.

• 한국식품영양과학회지
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• 제46권9호
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• pp.1122-1127
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• 2017

바나나 껍질과 파인애플 껍질에서 식품의 향에 가장 많이 사용되는 ethyl butyrate를 합성할 수 있는 ester synthetase의 최적 조건을 확립하고자 반응표면분석(response surface methodology, RSM)을 사용하였다. RSM 분석 결과 바나나 껍질에서 회수한 ester synthetase의 ethyl butyrate 합성 최적 조건은 ethanol의 농도가 38.7050 mM, butyric acid의 농도가 50.9019 mM, 반응시간이 4.3662시간일 때 최대 예측값은 45.8199 mM이었다. 파인애플 껍질에서 회수한 ester synthetase의 ethyl butyrate 합성 최적 조건은 ethanol의 농도가 54.6502 mM, butyric acid의 농도가 58.7638 mM, 반응시간이 4.7436시간일 때 최대 예측 값은 65.1087 mM임을 알 수 있었다. 결론적으로 ethyl butyrate 합성을 위해서는 바나나 껍질에서 회수한 ester synthetase보다는 파인애플 껍질에서 회수한 ester synthetase가 더 효율이 높음을 알 수 있었다. 앞으로 이들의 연속 대량 생산을 위해서 효소의 고정화 방법과 연속적인 기질 투입을 위한 기술 등의 개발이 더 이루어진다면 천연향 원료의 개발이 가능할 것으로 판단된다.

• 신재생에너지
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• 제8권2호
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• pp.24-32
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• 2012

Natural gas hydrates have a high potential as the 21st century new energy resource, because it have a large amount of deposits in many deep-water and permafrost regions of the world widely. Natural gas hydrate is formed by physical binding between water molecule and gas mainly composed of methane, which is captured in the cavities of water molecules under the specific temperature and pressure. $1m^3$ methane hydrate can be decomposed to the methane gas of $172m^3$ and water of $0.8m^3$ at standard condition. Therefore, there are a lot of practical applications such as separation processes, natural gas storage transportation and carbon dioxide sequestration. For the industrial utilization of methane hydrate, it is very important to rapidly manufacture hydrate. However, when methane hydrate is artificially formed, its reaction time may be too long and the gas consumption in water becomes relatively low, because the reaction rate between water and gas is low. So in this study, hydrate formation was experimented by adding natural zeolite and Synthetic zeolite 5A in distilled water, respectively. The results show that when the Synthetic zeolite 5A of 0.01 wt% was, the amount of gas consumed during the formation of methane hydrate was higher than that in the natural zeolite. Also, the natural zeolite and Synthetic zeolite 5A decreased the hydrate formation time to a greater extent than the distilled water at the same subcooling temperature.

• Bulletin of the Korean Chemical Society
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• 제27권2호
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• pp.203-207
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• 2006

Isomeric series of dilinked $NO_2S_2$ macrocycles ($L^2$: para-, $L^3$: meta- and $L^4$: ortho-linked) capable of binuclear complexing ability were prepared from its monomeric analog $L^1$ in reasonable yields except ortho-type reaction, which led to mixture due to the formation of monomer-type macrocyclic quaternary ammonium bromide $L^5$. Moreover, L2 (as $2HNO_3$ form) and $L^5$ were confirmed by an X-ray crystallography. Reaction of $HgCl_2$ with $L^2$ yielded a binuclear complex $[Hg_2(L^2)Cl_4]$. In the complex, each mercury(II) has a distorted tetrahedral environment made up of S and N donors from an exodentate $L^2$ and two coordinated Cl atoms.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.75.1-75.1
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• 2011

Coal gasification is considered as one of the most prospective technologies in energy field since it can be utilized for various products such as electricity, SNG (Synthetic Natural Gas or Substitute Natural Gas) and other chemical products. Among those products from coal gasification, SNG is emerging as a very lucrative product due to the rising prices of oil and natural gas, especially in Asian countries. The process of SNG production is very similar to the conventional IGCC in that the overall process is highly dependent on the type of gasifier and coal rank. However, there are some differences between SNG production and IGCC, which is that SNG plant requires higher oxygen purity from oxygen plant and more complex gas cleanup processes including water-gas shift reaction and methanation. Water-gas shift reaction is one of the main process in SNG plant because it is a starting point for the latter gas cleanup processes. For the methanation process, syngas is required to have a composition of $H_2$/CO = 3. This study reviewed various considerations for water-gas shift process in a conceptual design on an early stage like a feasibility study for a real project. The factors that affect the design parameters of water-gas shift reaction include the coal properties, the type of gasifier, the overall thermal efficiency of the plant and so on. Water-gas shift reaction is a relatively proven technology compared to the other processes in SNG plant so that it can reduce technological variability when designing a SNG project.

• 생명과학회지
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• 제16권1호
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• pp.1-5
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• 2006

본 연구는 Penibacillus polymyxa 균주의 CFTase 유전자를 결손 변이시킨 고효율 효소 CFT108을 이용하여 cyclofructan (CF)의 대량생산 조건을 검토하고 생산된 CF의 순수 분리 정제 공정을 개발하였다. CF의 대량생산 조건은 $2\%$의 inulin 기질과 40 unit/g inulin의 기질에서 3시간 반응시켰을 때 최대 생산량 9.5 g/l의 수율을 달성할 수 있었으며, 이때의 in-ulin의 CF 전환율은 $47.5\%$였다. 생산된 CF를 순수 분리 정제하기 위해서 CFTase 반응액 을 exoinulinase 1 unit/ml로 6시간 처리하여 미 반응 inulin을 단당화시켰으며, 유리된 fructose는 $3\%$ CaO로 $CO_2$가스 하에서 $80^{\circ}C$, 10분간 3회 흡착제거 시킴으로써 순수 정제하였다. 정제된 CF를 HPLC로 확인한 결과 정제도는 $95\%$ 이상이였으며, $CF_6,\;CF_7,\;CF_8$ 비율이 72 : 27 : 1 이였다.

• Bulletin of the Korean Chemical Society
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• 제28권9호
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• pp.1467-1471
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• 2007

The green-emitting CeMgAl11O19:Tb (CMAT) phosphor has been prepared at 1200 °C by the simple solid-state reaction using AlF3 as a self-flux. This preparation temperature is much lower than those (1500-1700 °C) for conventional solid-state reaction and spray pyrolysis method. In particular, the complete process to produce high-quality phosphor particles was carried out through the single-step heat treatment of the mixture of corresponding oxide-type metal sources. An addition of AlF3 as a self-flux significantly decreased the crystallization temperature of CMAT with plate-like shape. The particle morphology could be controlled from plate-like to spherical by using H3BO3 as an additional flux. Thus, an optimal morphology and luminescence characteristics of CMAT were achieved when both AlF3 and H3BO3 fluxes were simultaneously used. Compared with conventional solid-state process, which is accompanied by the calcination step(s), and other alternative liquid solution techniques such as sol-gel method and spray pyrolysis, no use of active precursors and liquid media that are harmful to the environment is a distinctive advantage for the industrial purpose.

• Journal of the Korean Wood Science and Technology
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• 제25권1호
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• pp.1-7
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• 1997

Kraft oak lignin and ricestraw lignin from acetosolve pulping were dissolved in 50/50 mixture of tetralin/m-cresol solvent. The dissolved lignin was reacted in the pressurized autoclave which was operating at $350{\sim}500^{\circ}C$ of reaction temperature and 10~20 atms of reaction pressure respectively_Hydrogen pressure of 60~80kg/$cm^2$ was exercising into the pressurized autoclave reactor to create thermochemical hydrogenolysis reaction. It was identified by GLC, GC-MS and HPLC that the alkyl-aryl-${\beta}$-O-4 ether bond of lignin was cleaved and degraded into various smaller molecules of aromatic compound such as phenols and cresols under the reaction conditions around $300^{\circ}C$ and 10 atms of reaction temoerature and pressure. Hydrogenolysis reaction of lignin compound which was done above $500^{\circ}C$ of reaction temperature and 20 atms of reaction pressure showed that the amount of aromatic compound such as phenols and cresols degraded from reactant lignin was decreasing with newly present and increasing water out of product mixtures. It was supposed that new aliphatic compound of high molecular weight hydrocarbon is composed due to higher reaction temperature and pressure of hydrogenolysis reaction such as $500^{\circ}C$ and 20 atms, even though it was almost impossible, to identify what kind of degraded products it was by HPLC.