• 에너지공학
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• 제28권4호
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• pp.8-12
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• 2019

Thermal amine scrubbing is the most advanced CO₂ capture technique but its largescale application is hindered due to the large heat requirement during solvent regeneration step. The addition of a solid metal oxide catalysts can optimize the CO₂ desorption rate and thus minimize the energy consumption. Herein, we evaluate the solvent regeneration performance of Monoethanolamine (MEA) and Diethanolamine (DEA) solvents without and with two metal oxide catalysts (TiO₂ and V₂O₅) within a temperature range of 40-86℃. The solvent regeneration performance was evaluated in terms of CO₂ desorption rate and overall amount of CO₂ desorbed during the experiments. Both catalysts improved the solvent regeneration performance by desorbing greater amounts of CO₂ with higher CO₂ desorption rates at low temperature. Improvements of 86% and 50% in the CO₂ desorption rate were made by the catalysts for MEA and DEA solvents, respectively. The total amount of the desorbed CO₂ also improved by 17% and 13% from MEA and DEA solvents, respectively. The metal oxide catalyst-aided regeneration of amine solutions can be a new approach to minimize the heat requirement during solvent regeneration and thus can remove a primary shortfall of this technology.

• 한국화재소방학회논문지
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• 제22권3호
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• pp.234-238
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• 2008

수소의 연소과정 중 하나인 자연발화에 대해 HFP를 첨가하였을 때 발화 지연을 수치해석을 통하여 조사하였다. 단열 밀폐시스템에서 대기압 하에서의 비정상 상태를 가정하였으며, 수소/공기/헵타플루오르헵탄(HFP)의 반응기구는 93개의 화학종과 817개의 화학반응식을 고려하였다. 먼저 이론당량비의 순수한 수소/공기 혼합기 계산결과로부터 연료와 산화제만 존재하는 혼합기에서는 자연발화시간을 결정하는 판별방법의 선택은 그리 중요하지 않고, 대부분의 판별방법이 잘 일치하는 결과를 얻을 수 있었다. 또한 수소/공기의 자연발화시간은 기존문헌의 실험결과와 잘 일치함을 알 수 있어 사용된 수소반응기구를 검증할 수 있었다. HFP를 수소/공기 혼합기에 섞었을 경우에는 각 순간적 화학적 반응에 의해 OH농도의 변곡점이 다양한 시각에 나타나므로 온도의 변곡점으로 발화시간을 판단하는 것이 보다 타당하다는 결과를 얻었다. 그리고 HFP의 농도가 10% 이상인 경우 큰 발화지연효과를 볼 수 있는데, 이 때, HFP 농도가 증가할수록 희석효과에 비해 화학적 효과가 발화시간 지연에 보다 크게 기여함을 알 수 있다.

• 한국염색가공학회지
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• 제27권4호
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• pp.281-287
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• 2015

The aim of this study was to investigate the possibility utilizing Metasequoia(Metasequoia glyptostroboides) cone as a new natural dye resource. In previous study, dyeing onto cotton fiber was carried out and Metasequoia cone colorant showed low affinity to cotton fiber and maximum dye uptake was obtained at pH 3.5 showing YR Munsell color. For further evaluation of its efficacy as a new natural dye resource, effects of dyeing conditions and mordanting on dye uptake, color change, and colorfastness were investigated for silk fiber. Metasequoia cone colorant showed good affinity toward silk fiber showing YR Munsell color and maximum dye uptake was shown at pH 3.5. Post-mordanting with Cu and Fe improved dye uptake, especially Fe($C_5H_{10}FeO_6$) mordant was effective as much as 2 times higher dye uptake comparing with un-mordanted sample. The color of dyed fabrics with mordanting showed YR Munsell color. Fe mordanted fabrics appeared dark gray~black color. Colorfastness to washing was relatively good, whereas lightfastness of the dyed fabrics showed grade 2. It was confirmed that Metasequoia cone colorant can be used as a new dye resource for silk fiber getting brownish yellow to dark gray/black color depending on mordant type. In addition, it showed antimicrobial functionality.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2001년도 추계학술발표대회
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• pp.681-684
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• 2001

농작물 종자의 발아를 억제하는 미생물, Pseudomonas sp. F721을 자연계로부터 분리 및 동정하였다. 그리고 식물성장 호르몬에 의하여 발아억제물질이 유도되어 생산됨이 밝혀졌다. 분리된 균주의 최적 배양조건을 검토한 결과, $35^{\circ}C$, pH 9.0, 15Orpm, 48 hr, substrate 0.5% (w/v), strain 1.0% (v/v)이었다. 발아억제의 정도는 종자의 종류에 따라 차이가 있었다. 발아억제물질의 물리${\cdot}$화학적 안정성 검토결과 pH 2.0${\sim}$12.0, $-20{\sim}100^{\circ}C$에서 대하여 안정성을 가지고 있었다. 발아억제 물질은 발아 초기에 대조 시험보다 약 90% 이상 발아를 억제하였다.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1997년도 Proceedings of the 12th KACG Technical Meeting and the 4th Korea-Japan EMGS (Electronic Materials Growth Symposium)
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• pp.207-209
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• 1997

Influences of boron addition on the oxygen solubiligy in silicon melt and the amount of evaporation loss from the melt surface were investigated. It has been found the oxygen concentration increases from 2${\times}$1018 to 4${\times}$1018 atoms/㎤. The amount of evaporation loss was found to vary widely depending on the melt temperature. The amount of SiO evaporating form boron doped (∼102121 atoms/㎤) silicon melt at 1550$^{\circ}C$ is about twice as much as the value of non-doped melt.

• 동력기계공학회지
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• 제8권2호
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• pp.53-58
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• 2004

In this paper, the semi active mount featuring Magneto rheological fluid(MR Fluid) is proposed. MR fluid is suspension of micro sized magnetizable particles in a fluid medium, and its apparent viscosity can be varied by the applied strength of magnetic field. When the controllable MR fluid is applied to mechanical devices, the devices provide simple, rapid response interfaces between electronic controls and mechanical systems. The MR fluid is applied in the conventional fluid mount for improving its performance of the mount's isolation effect. A appropriate size of the MR mount is designed and manufactured on the basis of Bingham model of MR fluid. In addition, the field dependent damping forces of MR mount are evaluated with respect to the input frequency variation.

• 한국미생물·생명공학회지
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• 제22권4호
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• pp.368-372
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• 1994

Three more unusual macrolides in addition to concnamycin B were isolated from the mycelium of Streptomyces sp. strain Bal6. These four compounds showed a potent cytotoxity to hunian cancer cell lines, SNU-1 (stomach cancer cell line), SNU-354 (liver cancer cell line), MCF- 7 (breast cancer cell line) and KB-3-1 (oral epidermoid carcinoma cell line). Interestingly, these compounds confered slight differential cytotoxity on RHEK-1, a human epidermal keratinocyte cell line immotalized by AD12-SV40 hybrid virus and RHEK-1/pSV$_{2}$ ras which was resulted from H-ras transfomation of RHEK-1. These compounds were determined to be concanamycin A, conca- namycin E and 0-methyl concanamycin B by NMR and other spectral analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 D
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• pp.1490-1492
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• 1998

The methastable state diamond films have been deposited on Si substrates using MWPCVD. Effects of each experimental parameters of MWPCVD including $CH_4$ conentrations, Oxygen additions, Operating pressure, etc. on the growth rate and crystallinity were invesitigated. The best crystallinity of the film at 3% methane concentration addition of oxygen to the $CH_4-H_2O$ mixture gave an improved film crystallinity at 50% oxygen concentration. Upon increasing the operating pressure, the growth rate and crystallinity were increased simultaneously.

• 한국세라믹학회지
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• 제38권6호
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• pp.499-505
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• 2001

The behaviour of ionic compound crystals under combined chemical and externally applied electrical potential gradients is discussed. Firstly, a systematic overview is given. Then a formal analysis follows. The transport equations of the ions and the electric defects predict that even with reversible electrodes demixing, and in particular decomposition of the compound will occur if the applied d.c. current density is sufficiently high. These predictions are illustrated by appropriate experiments. With the help of the solid solution (Me, Fe)O, where Fe-ions are the dilute species, we investigate experimentally the behaviour of a ternary ionic crystal under a d.c. electric current load. All the compounds were placed in a galvanic cell, and the internal reactions which then could be observed were driven by the electric field in this cell. In addition, we discuss the influence of the electric field on the classical solid state reaction AX+BX=ABX$_2$, if again the reaction couple is placed in a galvanic cell.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• 제4권4호
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• pp.227-230
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• 2000

Bunker-A oil-degrading microorganisms were isolated from a marine environment using an enrichment culture technique. The isolated strain EL-081K was identified as the genus Acinetobacter based on the results of morphological, culture, and biochemical tests. The optimal temperature and initial pH for bunker-A oil degradation were $25^{\circ}C$ and 7.0, respectively, including aeration. The optimal medium composition for the degradation of bunker-A oil by Acinetobacter sp. EL_O81K was 10 ml/l bunker-A oil as the carbon source and 0.1% (NH$_4$)$_2$SO$_4$as the nitrogen source. Under the above conditions, the biodegradability of bunker-A oil was 38% after 96 hours of incubation. The addition of detergent did not increase the bunker-A oil degradation.