• 한국수소및신에너지학회논문집
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• 제16권4호
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• pp.356-363
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• 2005

The purpose of this paper is to investigate the optimal condition of the Syngas production by reforming of fuel using plasmatron. Plasma was generated by air and arc discharge. The effects of applied steam, $CO_2$ or Ni-catalyst on fuel conversion, as well as hydrogen yield and $H_2$/CO ratio were studied. When the variations of $O_2$/fuel ratio, $H_2O$/fuel flow ratio and $CO_2$/fuel flow ratio were $0.94{\sim}1.48$, $4.3{\sim}10$ and $0.8{\sim}3.05$, respectively. Under the condition mentioned above, result of $H_2O$/fuel flow ratio was maximum $H_2$ concentration, or $28.2{\sim}31.6%$, and result of $H_2O$/fuel flow ratio with catalyst was minimum CO concentration or $6.6{\sim}7.1%$. and $H_2$/CO ratio were $3.89{\sim}4.86$.

• KSBB Journal
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• 제24권2호
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• pp.212-215
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• 2009

본 연구에서는 식물세포배양으로부터 항암물질 paclitaxel을 고 순도, 고 수율로 분리 가능한 액-액 추출 공정에서의 주요 공정 변수들을 최적화 하였다. 액-액 추출을 위한 최적의 유기용매 (methylene chloride) 첨가량, 추출횟수, 혼합시간, 정체시간은 각각 0.28 (v/v), 3 (times), 30 min, and 40 min 임을 알 수 있었다. 액-액 추출 공정은 특히 메탄올을 이용한 biomass 추출물에 포함되어 있는 다량의 극성불순물을 제거하는데 매우 효과적이었다. 또한 액-액 추출 후 농축조건으로는 후속공정에서의 높은 순도의 paclitaxel 뿐만 아니라 작업의 용이성 측면에서 액-액 추출액을 rotary evaporator로 완전히 농축하는 것이 가장 바람직함을 알 수 있었다.

• Structural Engineering and Mechanics
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• 제74권1호
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• pp.19-32
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• 2020

Metallic energy-dissipation dampers are widely used in structures. They are comprised of an added damping and stiffness (ADAS) device with many parallel, diamond-shaped hole plates, the neck width of which is an important parameter. However, no studies have analyzed the neck width's influence on the ADAS device's performance. This study aims to better understand that influence by conducting a pseudo-static test on ADAS, with three different neck widths, and performing finite element analysis (FEA) models. Based on the FEA results and mechanical theory, a design neck width range was proposed. The results showed that when the neck width was within the specified range, the diamond-shaped hole plate achieved an ideal yield state with minimal stress concentration, where the ADAS had an optimal energy dissipation performance and the brittle shear fracture on the neck was avoided. The theoretical values of the ADAS yield loads were in good agreement with the test values. While the theoretical value of the elastic stiffness was lower than the test value, the discrepancy could be reduced with the proposed modified coefficient.

• 한국태양에너지학회 논문집
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• 제33권5호
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• pp.89-94
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• 2013

This paper presents a simple but valid design factor calculation method of grid-connected photovoltaic system using normalized yield model. The proposed calculation method can be represented as a quantitative value about five design factors from irradiance to system output power. The validity of this method is identified by analyzing design factor with three years monitored data. These results will indicate that it is useful to determine the optimal design and selection of grid-connected photovoltaic system to meet different user purposes and enhance long-term reliability and stability of grid-connected photovoltaic system.

• 한국토양비료학회지
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• 제49권5호
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• pp.461-468
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• 2016

One of the important phytohormones produced by plant growth promoting bacteria is the auxin; indole-3-acetic acid (IAA), with L-tryptophan as the precursor. In this study, we focused on the investigation of optimal conditions for the production of IAA by Bacillus megaterium BM5. We investigated culturing conditions, such as incubation temperature, pH of the culture medium and incubation period, with varying media components such as inoculation volume, tryptophan concentration and carbon and nitrogen source. Besides, optimization study intended for high IAA production was carried out with fermentation parameters such as rpm and aeration. The initial yield of $42{\mu}g\;IAA\;ml^{-1}$ after 24 hr increased to $85{\mu}g\;ml^{-1}$ when 5% (v/v) of L-tryptophan was used in the culture broth. The maximum yield of $320{\mu}g\;IAA\;ml^{-1}$ was observed in trypticase soy broth (TSB) supplemented with starch and soybean meal as C and N sources with a C/N ratio of 3:1 (v/v) at $30^{\circ}C$, pH 8.0 for 48 hrs with 1.0 vvm and 250 rpm in 5 L working volume using 10 L scale fermenter. The bacterial auxin extracted from the culture broth was confirmed by thin layer chromatography and high-performance liquid chromatography and effect on plant growth was confirmed by root elongation test.

• 한국약용작물학회지
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• 제17권6호
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• pp.415-420
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• 2009

This study was carried out to select economical byproduct composts as the substitute for the traditional organic fertilizer, Yacto, in the cultivation of ginseng seedlings, and to investigate the application method of a selected compost. Among tested byproduct composts, popped rice hull compost was the best substitute for Yacto, while the application of domestic animal manure composts resulted in red skinned roots of ginseng seedlings. Optimal mixing ratio of the popped rice hull compost with virgin soil (fine sand) were 3~4 : 1 in bulk, showing the same root yield compared to that of conventional seedbed soil. When the popped rice hull compost was lower than $1\;{\pm}\;0.1%$ in nitrogen content, the expeller cake of oil seed was added to seedbed soil to rise nitrogen content until $1\;{\pm}\;0.1%$.

• 한국환경과학회지
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• 제5권1호
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• pp.43-50
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• 1996

Thiobacillus neopolitanus R-10, which produces a active thiosulfate oxidase was isolated from nightsoil. The optimal culture conditions of Thiobacillus neopolitanus R-10 for the production of enzyme was determined as followed: 0.8% $Na_2S_2O_3$, 0.2% $KH_2PO_4$, 0.2% $K_2HPO_4$, 0.04% $Na_2CO_3$, 0.02% $MgSO_4$.$7H_2O$, 2ml trace elements solution, ann PH 6.5 at 3$0^{\circ}C$ and 72hr cultivation. The oxidase was successively purified 83 folds yield by ${(NH_2)}_2SO_4$ fractionation, DEAE-Cellulose, Sephadex A-50 column chromatogrophy and gel Sephadex G-150 gel filteration with yield of 5.9%. The molecular weight of purified enzyme was estimated to be 43.000 dalton by SDS-polyacrylamide gel electrophoresis and gel filteration column chromatography The enzyme activity was highest at 40t and PH 7.0 The enzyme activity was relatively high by $\beta$-mercaptoethanol but strongly inhibited by cysteine.

• 한국미생물·생명공학회지
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• 제16권6호
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• pp.505-509
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• 1988

Xylose 발효효모를 토양에서 분리하였으며 (X-6-41) 이는 Lodder씨 분류기준에 따라 Candida 속으로 동정되었다. 삼각플라스크 정치배양법에 의한 xylose 발효시 2% xylose, N원 asparagine, pH 4에서 발효율 약 80%로 나타났고 Mini-Jar for mentor를 이용하여 glucose와 xylose를 1 : 1로 혼합한 총당 5% 기질에서 발효를 시켜 본 바 발효율은 총당에 대해 약 72.3%(alcohol 2.3%(v/v)였다. 본 균주에 의한 xylose 발효는 일반적으로 보고된 바와 같이 호기적 발효과정이였으며 glucose와 xylose 혼합기질의 경우 glucose가 먼저 이용되고 xylose가 나중에 이용되는 것으로 나타났다. 5% xylose를 기질로 하여 Mini-Jar fermentor에서 발효시켰을 때 최대 발효율 69%(alcohol 2.2%(v/v)로 나타났으며 발효중에 xylitol이 생성되었다.

• 한국미생물·생명공학회지
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• 제12권4호
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• pp.261-264
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• 1984

증자하지 않은 cassava 생전분의 ethanol 발효생산을 위한 동시당화 -발효의 최적조건을 검토하였다. 생전분의 분해력이 가장 좋은 당화효소의 선별에서는 Asp. shirousami27이 가장 좋았으며 발효효모는 균주에 따라 큰 차이가 없는 것으로 나타났다. 동시당화-발효는 pH3.6에서 가장 높았으며 발효전 6$0^{\circ}C$에서 당화효소에 의한 전당화와 발효시 교반등이 발효속도 및 발효율에 효과가 있었고, 분쇄처리도 효과가 있었다. cassava 생전분의 동시당화-발효에서 5일간의 긴 발효 기간을 요구하는데 발효중 발효액의 성분 조사 결과 중간물인 glucoserk 축적되지 않는 것으로 당화과정이 속도결정단계임을 알 수 있다.

• Nuclear Engineering and Technology
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• 제51권3호
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• pp.738-745
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• 2019

Coprecipitation using hydrous ferric oxide (HFO) has been effectively used for the removal of radionuclides from radioactive wastewater. This work studied the dynamic behavior of HFO floc formation during the neutralization of acidic ferric iron in the presence of several radionuclides by using a photometric dispersion analyzer (PDA). Then the coagulation-flocculation system using HFO-anionic poly acrylamide (PAM) composite floc system was evaluated and compared in seawater and distilled water to find the effective condition to remove the target nuclides (Co-60, Mn-54, Sb-125, and Ru-106) present in wastewater generated in the severe accident of nuclear power plant like Fukushima Daiichi case. A ferric iron dosage of 10 ppm for the formation of HFO was suitable in terms of fast formation of HFO flocs without induction time, and maximum total removal yield of radioactivity from the wastewater. The settling time of HFO flocs was reduced by changing them to HFO-PAM composite floc. The optimal dosage of anionic PAM for HFO-anionic PAM floc system was approximately 1-10 ppm. The total removal yield of Mn-54, Co-60, Sb-125, Ru-106 radionuclides by the HFO-anionic PAM coagulation-flocculation system was higher in distilled water than in seawater and was more than 99%.