• 청정기술
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• 제15권2호
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• pp.75-80
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• 2009

공기 중에서 산소를 분리하기 위하여 2탑 PSA 공정을 이용한 4단계 기본공정 공급기체의 유량과 세정기체의 유량이 생성물의 순도와 유량에 미치는 영향을 살펴보았다. 4단계 기본 공정에 생성물가압 단계를 도입하면 생성물의 순도와 유량을 증가시키고, 압력균등화단계를 도입한 경우에는 생성물의 유량이 크게 증가한다는 사실을 확인할 수 있었다. 현재 상용화되어 있는 의료용 산소 발생기 사양인 5 ${\ell}/min$ 유량에서 순도 90%의 산소를 얻기 위해 시제품을 제작하여 산소의 순도 및 유량에 관한 실험을 수행하였다.

• Journal of the Korean Wood Science and Technology
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• 제52권1호
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• pp.31-46
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• 2024

Subterranean termite attacks on cajuput (Melaleuca cajuputi) seedling roots were widespread in several of Java's Perum Perhutani Forest Management Units. This attack was suspected to be related to the chemical components of the cajunput seedling roots. This study was conducted to determine the bioactivity of cajuput seedling root extract as an attractant for the subterranean termite Coptotermes curvignathus Holmgren (Isoptera: Rhinotermitidae). The extraction process was performed according to ASTM D1108-96, and the extract was characterized using gas chromatography-mass spectrometry (GC-MS). Bioactivity testing of the extracts was carried out using attractiveness and no-choice feeding bioassays. The results showed that the average root extraction yield from cajunput seedlings was 4.94%. The attractiveness of the extract solutions at concentrations of 0.50%, 0.75%, and 1.00% were 45.33%, 62.00%, and 74.67%, respectively. The mortality rate of C. curvignathus termites ranged from 9.63% to 24.44%. Cajuput seedling root extract's lethal concentration 50 was 2.45% (non-toxic). GC-MS analysis showed that the extract contained linoleic acid, which has the potential to attract insects.

• Natural Product Sciences
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• 제14권3호
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• pp.182-186
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• 2008

Scutellaria baicalensis Georgi (SBG) is traditionally used medicinal herb that has anti-oxidant, anticancer and anti-inflammatory effects. In this study, we investigated whether the extracts of SBG have the inhibitory activity in the osteoclast differentiation by using mouse monocytes RAW264.7 cells and primary mouse bone marrow-derived macrophages (BMMs). Methanol extract (ME) from SBG was successively fractionated into methylene chloride (MF), ethylacetate (EF) and n-butanol fraction (BF). The activity assay for tartrateresistant acid phosphatase (TRAP) and Western blot analysis were employed to evaluate the osteoclasts differentiation and the activation of mitogen-activated protein (MAP) kinases, respectively. ME, MF, EF and BF significantly and dose-dependently inhibited osteoclast differentiation without the decrease of cell viability at the concentrations used in this study. In addition, ME significantly inhibited the activation of c-jun-N-terminal kinase (JNK). In conclusion, this study firstly demonstrated that ME of SBG has the potential to inhibit the osteoclast differentiation through the suppression of JNK activation partially.

• Journal of Microbiology and Biotechnology
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• 제19권4호
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• pp.416-423
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• 2009

Hepatitis B core antigen(HBcAg) is an important serological marker used in the diagnosis of hepatitis B virus(HBV) infections. In the current study, a fast and efficient preparative purification protocol for truncated HBcAg from Escherichia coli disruptate was developed. The recombinant HBcAg was first captured by anion exchange expanded bed adsorption chromatography integrated with a cell disruption process. This online capture process has shortened the process time and eliminated the "hold-up" period that may be detrimental to the quality of target protein. The eluted product from the expanded bed adsorption chromatography was subsequently purified using size-exclusion chromatography. The results showed that this novel purification protocol achieved a recovery yield of 45.1% with a product purity of 88.2%, which corresponds to a purification factor of 4.5. The recovered HBcAg is still biologically active as shown by ELISA test.

• 한국응용과학기술학회지
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• 제23권4호
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• pp.307-318
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• 2006

The pyrolysis of high density polyethylene(HDPE) and low density polyethylene(LDPE) was carried out at temperature between 425 and $500^{\circ}C$ from 35 to 80 minutes. The liquid products formed during pyrolysis were classified into gasoline, kerosene, gas oil and wax according to the petroleum product quality standard of Korea Petroleum Quality Inspection Institute. The conversion and yield of liquid products for HDPE pyrolysis increased continuously according to pyrolysis temperature and pyrolysis time. The influence of pyrolysis temperature was more severe than pyrolysis time for the conversion of HDPE. For example, the liquid products of HDPE pyrolysis at $450^{\circ}C$ for 65 minutes were ca. 30wt.% gas oil, 15wt.% wax, 14wt.% kerosene and 11wt.% gasoline. The increase of pyrolysis temperature up to $500^{\circ}C$ showed the increase of wax product and the decrease of kerosene. The conversion and yield of liquid products for LDPE pyrolysis continuously increased according to pyrolysis temperature and pyrolysis time, similar to HDPE pyrolysis. The liquid products of LDPE pyrolysis at $450^{\circ}C$ for 65 minutes were ca. 27wt.% gas oil, 18wt.% wax, 16wt.% kerosene and 13wt.% gasoline.

• Journal of Radiation Protection and Research
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• 제29권1호
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• pp.33-39
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• 2004

In order to vitrify the W1 waste (ion-exchange resin(IER), zeolite, and dry active waste(DAW)) generated from Korean Nuclear Power Plants, a glass formulation development based on waste compositions and production rates was performed. A aluminoborosilicate glass, AG8W1, was formulated to vitrify the W1 waste in an induction cold crucible melter(CCM). The processability, product performance, and economics of the candidate glass were calculated using a computer code and were measured experimentally in the laboratory and CCM. The glass viscosity and electrical conductivity as the process parameters were in the desired ranges. Start-up and maintaining glass melt of the candidate glass were favorable in the CCM. The product quality of the glass such as chemical durability, phase stability, etc. was satisfactory. The vitrification process using the candidate glass was also evaluated to be operated as economically as possible.

• 대한화학회지
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• 제61권5호
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• pp.244-250
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• 2017

Reduction of (${\pm}$)-3-ketoproline ethyl ester (1) by $NaBH_4$ in the presence of $CaCl_2$ and $MgCl_2$ as the chelating agents gave selective products cis-3(R/S)-alcohols, while reduction by $NaBH_4$ alone or chelated with $NiCl_2$ and $AlBr_3$ gave mixtures of cis- and trans-alcohols. The reduction of (${\pm}$)-1 by various vegetables however, gave exclusively the cis-alcohol as the major and trans-alcohol as the minor. On the contrary, reduction of (${\pm}$)-1 by carrot afforded a mixture of cis- and trans-alcohols, in which the trans-alcohol exists as the major product. In addition, we found that this biocatalyst selectively converted S-enantiomer of (${\pm}$)-1 to the cis-alcohol, and R-enantiomer to a mixture of cis- and trans-alcohols with cis-alcohol as the major product. This fact prompted us to use various fresh plant tissues for stereoselective reduction of diverse types of pyrrolidinones, as its stereoselectivity towards racemic mixtures is higher compared to that using chemical reducing agents.

• 한국응용과학기술학회지
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• 제25권4호
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• pp.495-502
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• 2008

To investigate the synergy effect on the pyrolysis of mixture of polyethylene(PE) and polystyrene(PS), the pyrolysis of PE, PS and the mixture of PE-PS was carried out in a batch reactor at the atmospheric pressure and $450^{\circ}C$. The pyrolysis time was from 20 to 80 mins. The liquid products formed during pyrolysis were classified into gas, gasoline, kerosene, gas oil and heavy oil according to the distillation temperatures based on the petroleum product quality standard of Korea Institute of Petroleum Quality. The analysis of the product oils by GC/MS showed that the new components produced by mixing were not detected. The synergy effect according to mixing of PE and PS did not also appear. The conversion and yield of mixtures were in proportion to the mixing ratio of sample.

• 공업화학
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• 제3권4호
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• pp.588-594
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• 1992

Potassium octoate 촉매 존재하에 toluene diisocyanate(TDI)를 사용하여 polyisocyanurate를 합성할 때 용매에 포함된 수분과 부탄올이 반응물의 점도 변화율, 반응시간(생성물의 점도가 5 poise가 될 때까지의 반응시간), 생성물의 분자량 분포 및 TDI전환율에 미치는 영향을 고찰하였다. Butyl acetate용매에 포함된 수분의 양이 0.1%인 반응 조건에서 uretidione이 생성되었으며 이때 가장 높은 TDI전환율이 얻어졌다. Uretidione은 butanol을 용매에 첨가할 때는 생성되지 않았다. 첨가된 butanol양이 증가할수록 TDI전환율은 증가하고 분자량 분포도 넓어졌다.

• Food Science and Biotechnology
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• 제18권1호
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• pp.79-83
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• 2009

Acidolysis of olive oil with omega-3 (n-3) polyunsaturated fatty acids (PUFAs) was carried out to produce a structured lipid. Novozym $435^{(R)}$ from Candida antarctica was used as the biocatalyst. Response surface methodology (RSM) was used to determine optimum conditions for lipase-catalyzed enrichment of olive oil. Three factors, 5 levels, central composite design was used. The effects of incubation time, temperature, and substrate mole ratio on incorporation ratio (n-3 fatty acids/total fatty acids, %) were investigated. From the evaluation of response surface graphs, the optimal conditions for incorporation of long chain n-3 PUFAs into olive oil were $40-60^{\circ}C$ for temperature, 30-45 hr for reaction time, and 3:1-5:1 (n-3 fatty acids/olive oil) for substrate mole ratio. Experiments conducted under optimized conditions predicted by the model equation obtained from RSM yielded structured lipids with 50.8% n-3 PUFAs. This value agreed well with that predicted by the model. Oxidative stability tests showed that the product was more susceptible to oxidation than unmodified olive oil. Antioxidant addition improved the oxidative stability of the product.