• Proceedings of the Membrane Society of Korea Conference
• /
• 2004.05b
• /
• pp.168-171
• /
• 2004

이산화탄소는 메탄, 오존, 산화질소, CFC등의 온실기체 중 약 50%를 차지하는 물질로서 이산화탄소 발생의 저감과 함께 회수 기술의 개발을 통한 배출량 억제는 환경적 측면에서 대단히 중요한 것으로 간주되고 있다. 따라서 각종 산업분야에서 발생하는 다양한 성분을 가진 다성분계 배가스내에 존재하는 10%내외의 이산화탄소만을 분리정제 농축하여 메탄, 메탄올 등의 다른 화학물질의 제조의 원료, 신에너지원, 고부가가치의 신제품 등으로 전환하는 연구가 활발히 진행 중이다.(중략)

• Clean Technology
• /
• v.27 no.1
• /
• pp.9-16
• /
• 2021

Since the active matrix organic light-emitting diode (AMOLED) encapsulation process is very vulnerable to moisture and oxygen, high-purity nitrogen with minimal moisture and oxygen must be used. In this study, a copper-based catalyst used to remove oxygen from nitrogen in the AMOLED encapsulation process was optimized. Two-component and three-component catalysts composed of CuO, Al2O3, or ZnO were prepared through a co-precipitation method. The prepared catalysts were characterized by using BET, XRD, TPR, and XRF analysis. In order to verify the oxygen removal performance of the catalyst, several catalytic reactions were conducted in a fixed bed reactor, and the corresponding oxygen contents were measured through an oxygen analyzer. In addition, reusability of the catalysts was proven through repetitive regeneration. The properties and oxygen removal capacity of the catalysts prepared with CuO and Al2O3 ratios of 6 : 4, 7 : 3, and 8 : 2 were compared. The number of active sites of the catalyst with a ratio of CuO and Al2O3 of 8 : 2 was the highest among the 2-component catalysts. Moreover, the reducibility of the catalyst with a ratio of CuO and Al2O3 of 8 : 2 was the best as it had the highest CuO dispersion. As a result, the oxygen removal ability of the catalyst with a ratio of CuO and Al2O3 of 8 : 2 was the best among the 2-component catalysts. The best oxygen removal capacity was obtained when 2wt% of ZnO was added to the sub-optimized catalyst (i.e., CuO : Al2O3 = 8 : 2) probably due to its outstanding reducibility. Furthermore, the optimized catalyst kept its performance during a couple of regeneration tests.

• Korean journal of food and cookery science
• /
• v.10 no.1
• /
• pp.45-50
• /
• 1994

Conventional Doenjang, three kinds of Improved Doenjang(A; koji: soybean: salt=53: 100: 33, B; koji: soybean: salt=100: 100: 40, C; koji: soybean: salt= 200: 100: 40) prepared with different ratio of koji and salt were made to study the changes in the general contents, characteristics bitter peptides, correlations between bitterness and overall eating quality. 1. Total nitrogen contents increased a little, and amino nitrogen contents in all samples increase markedly. Especially, Amino nitrogen contents of conventrional Doenjang increased more than others. Reducing sugars of doenjang prepared with Asp. oryzae were higher than conventional Doenjang and increased throughout the aging period and Doenjang prepared with Asp. oryzae were more acidic. 2. To characterize bitter peptides in fermented Doenjang, peptides were extracted with 2: 1(v/v) chloroform-methanol and separated by Gel chromato-graphy with Sephadex and TLC. After Gel chromatography and TLC, each fraction examined presence of bitterness and evaluated intensity of bitterness. Amino acid composition of the fractions showing bitter tastes were as follows. Conv. peak 1-1 Trp-(Asp, Arg, Thr, Ser, Glu, Pro)-Phe Imp. A peak 1 Trp-(Glu, Val, Arg, lie)-Phe Imp. B peak 1 Trp-(lie, Pro, Asp, Lys, Val, Glu)-Trp. Imp. C peak 1-2 Trp-(Try, Thr, Glu, Pro, Gly)-Phe 3. Sensory evaluation revealed that correlation coefficient between bitterness and overall eating guality was not high.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.6
• /
• pp.1287-1291
• /
• 2009

The genes of cyanide hydratase(CHT), a kind of nitrilases whichhydrolyze cyanide to formamide were extracted from N. crassa and A. nidulans, the two fungal strains. The recombinant forms of the CHT originated from N. crassa and A. nidulans were prepared with N-terminal hexahistidine purificationtags or no tags, and expressed in E. coli. The enzymes were purified using immobilized metal affinity chromatography. They were compared according to their pH activity profiles, and kinetic parameters. The N. crassa CHT has the wider pH range of activity above 50% and three-fold higher turnover rate (6.6 ${\times}$ $10^8$ $min^{-1}$) than the A. nidulans, meanwhile the CHT of A. nidulans has the higher $K_m$ value. Expression of CHT in both N. crassa and A. nidulans were induced by the presence of KCN, regardless of any presence of nitrogen sources. Max. 82% of KCN was degraded in 60 min for biological degradation tests.

• Membrane Journal
• /
• v.20 no.4
• /
• pp.267-277
• /
• 2010

Gas separation membranes have been developed for decades in various areas to replace the conventional processes. Membrane processes for gas separation have many advantages of energy saving, compact size, and easy scale-up. Nowadays, gas separation processes is widely spreaded in nitrogen generating system, hydrogen generating system, membrane dryer, on board inert gas generating system, natural gas purification, biogas purification and fuel cells. Carbon dioxide separation process using membrane would be a strong candidate of carbon dioxide capturing process. In order to broaden the scope of application of gas separation membranes, development of new materials which can overcome the borderline of Robeson's plot should be necessary, so that many researchers and companies are trying to develop the new materials like polymers containing cardo and spiro group and PIMs (polymers for intrinsic microporosity).

• Journal of Ginseng Research
• /
• v.28 no.3
• /
• pp.127-131
• /
• 2004

This study was carried out to investigate the effect of red ginseng water extract (RGWE) on trypsin activity. After extraction of fat soluble and saponin component from red ginseng powder by methyl alcohol, the residue was extracted with distilled water, and manufactured to water extract. The extract was dialyzed with different molecular cut off membrane. Trypsin activity demonstrated the highest level at the RGWE concentration of 9${\times}$10$\^$-2/% in reaction mixture, and also increased to 15% at 2.9${\times}$10$\^$-3/%. Km value was decreased and Vmax was increased in the present of red ginseng water extract. Red ginseng water extract was partially purified by dialysis, Bio-Gel P-I0 and DEAE-cellulose column chromatography. The active fraction demonstrated positive reaction to ninhydrin, DNS and folin reaction.

• Korean Journal of Food Science and Technology
• /
• v.19 no.5
• /
• pp.420-425
• /
• 1987

For use of sardine oil as an ingredient of food and feed, crude sardine oil obtained by rendering was processed to RBD sardine oil. Alkali deacidification was found to be most efficient with a concentration of 2.5N NaOH and 0.5% excess level at $75^{\circ}C$. Treatment with activated clay alone at $105^{\circ}C$ for 20 min without air admission was effective in reduction of the color intensity of the oil without any formation of the conjugated dienes and trienes of polyunsaturated fatty acids. In deodorization process, as the temperature was increased, color of the oil was to become lighter. The amount of conjugated compounds was, however, increased drastically at higher temperatures above $180^{\circ}C$ for 1hr. and content of polyunsaturated fatty acids was significantly decreased.

• Analytical Science and Technology
• /
• v.15 no.6
• /
• pp.489-495
• /
• 2002

In this study, we determined distribution status of organonitrogen pesticides such as trifluralin, atrazine, metribuzin, alachlor, malathion, nitrofen, permethrin, cypermethrin, fenvalerate, and parathion accumulated in the fresh water fishes and amphibians. We collected those samples at 31 sites from the basin of major rivers, and separated the muscular tissue as a final sample for analysis. In the pretreatment process, lipid was eliminated by using acetonitrile and n-hexane, and pesticides were reextracted with dichloromethane. The extract was dehydrated and concentrated, and then cleaned it up by passing the Florisil column, and pesticide content was finally determined by using a GC-MS system after introducing isotope labelled references. The accumulation level was observed in the range of $0.17{\sim}6.8{\mu}g/kg$ in amphibians and $0.26{\sim}16{\mu}g/kg$ in fishes including cypermethrin as $16{\mu}g/kg$.

• Korean Chemical Engineering Research
• /
• v.56 no.6
• /
• pp.784-791
• /
• 2018

UiO-66 particles were synthesized under various synthesis conditions to study the adsorption of carbon dioxide for hydrogen purification. For the purpose, the design and analysis of experiments was performed using statistical design of experiment method. As the synthesis time, temperature and acetic acid amount increased, the crystallinity of UiO-66 particles increased. Especially, the amount of acetic acid was confirmed as an important factor in determining the crystallinity of the particles. The specific surface area of the particles measured by the nitrogen adsorption method also showed a similar tendency. Using the general factor analysis in the experimental design method, the main effects and interactions of major factors were analyzed. In addition, the carbon dioxide adsorption capacity was predicted using a nonlinear regression method. Then, the adsorption performance was shown through surface and contour maps for all ranges.

• Korean Journal of Soil Science and Fertilizer
• /
• v.31 no.2
• /
• pp.128-136
• /
• 1998

Most of total nitrogen in the surface soil exists in organic forms, of which amino acid-N is the major fraction. By-product fertilizers provide soil with humic substances, and humic acid is an essential component of humus. Amino acids(AAs) are easily converted to inorganic-N forms and thus play an important role in N fertility. This experiment was conducted to investigate the contents and distributions of AAs in humic acids which were extracted from the commercial by-product fertilizers of different composting materials. Total contents of AAs in humic acids ranged from 1.2 to 5.6%, of which neutral AAs were the highest with ranges of 0.8~4.5%. AAs contents in fertilizers composted from the plant residues such as leaf litter, sawdust and bark were in an order of neutral>acidic>basic AAs. In contrast, those from animal wastes, such as poultry and pig manures, were in an order of neutral>basic>acidic AAs. Distributions of total, acidic and neutral AAs were in the respective order of leaf litter>sawdust>pig manure>poultry manure>peat, bark>sawdust>leaf litter>peat and leaf litter>sawdust>bark>peat. Distributions of the basic AAs were in the reversed order of the acidic AAs. In bark fertilizer with increasing compost maturity, contents of the acidic AAs were increased in compensation for the decreases in those of neutral and basic AAs. Results demonstrated that distributions of amino acids in humic acid of by-product fertilizers were different from composting raw materials and degrees of humification.