• 대한화학회지
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• 제46권1호
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• pp.69-75
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• 2002

조합화학 기법을 이용하여 청색 및 적색 발광을 하는 $Y_{1-x}(P_{1-y-z}Nb_yV_z)O_4:Eu_x$ 형광체를 합성하였다. 합성한 $Y_{1-x}(P_{1-y-z}Nb_yV_z)O_4:Eu_x$ 형광체에 대하여 254 nm 및 147 nm 여기 하에서의 발광 세기에 관한 라이브러리를 완성하였고, 또한 형광체의 결정성과 입자 현상은 XRD와 SEM으로 특성을 관찰하였다. 조합검색 결과로부터 $Y_{1-x}(P_{1-y-z}Nb_yV_z)O_4:Eu_x$ 형광체의 발광특성은 P 자리에 치환되는 금속이온의 영향을 많이 받았다. 결과적으로 $Y_{0.88}PO_4:Eu_{0.12}$ 형광체와 비교하여 발광 효율이 우수한 새로운 $Y_{0.88}(P_{0.92}Nb_{0.05}V_{0.03})O_4:Eu_{0.12}$ 형광체를 찾아내었다.

• Journal of Microbiology and Biotechnology
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• 제31권1호
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• pp.154-162
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• 2021

L-5-methyltetrahydrofolate (5-MTHF) is one of the biological active forms of folate, which is widely used as a nutraceutical. However, low yield and serious pollution associated with the chemical synthesis of 5-MTHF hampers its sustainable supply. In this study, 5-MTHF production was improved by engineering the 5-MTHF biosynthesis pathway and NADPH supply in Lactococcus lactis for developing a green and sustainable biosynthesis approach. Specifically, overexpressing the key rate-limiting enzyme methylenetetrahydrofolate reductase led to intracellular 5-MTHF accumulation, reaching 18 ㎍/l. Next, 5-MTHF synthesis was further enhanced by combinatorial overexpression of 5-MTHF synthesis pathway enzymes with methylenetetrahydrofolate reductase, resulting in 1.7-fold enhancement. The folate supply pathway was strengthened by expressing folE encoding GTP cyclohydrolase I, which increased 5-MTHF production 2.4-fold to 72 ㎍/l. Furthermore, glucose-6-phosphate dehydrogenase was overexpressed to improve the redox cofactor NADPH supply for 5-MTHF biosynthesis, which led to a 60% increase in intracellular NADPH and a 35% increase in 5-MTHF production (97 ㎍/l). To reduce formation of the by-product 5-formyltetrahydrofolate, overexpression of 5-formyltetrahydrofolate cyclo-ligase converted 5-formyltetrahydrofolate to 5,10-methyltetrahydrofolate, which enhanced the 5-MTHF titer to 132 ㎍/l. Finally, combinatorial addition of folate precursors to the fermentation medium boosted 5-MTHF production, reaching 300 ㎍/l. To the best of our knowledge, this titer is the highest achieved by L. lactis. This study lays the foundation for further engineering of L. lactis for efficient 5-MTHF biosynthesis.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2004년도 Annual Meeting BioExibition International Symposium
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• pp.174-179
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• 2004

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2000년도 춘계총회,특별강연,심포지움,연구발표회
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• pp.19.1-19.1
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• 2000

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2000년도 춘계총회,특별강연,심포지움,연구발표회
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• pp.19.2-19.2
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• 2000

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2000년도 추계총회,초청강연,특별강연,연구발표회
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• pp.56.1-56
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• 2000

• 한국세라믹학회:학술대회논문집
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• 한국세라믹학회 2000년도 추계총회,초청강연,특별강연,연구발표회
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• pp.57.2-57
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• 2000

• Bulletin of the Korean Chemical Society
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• 제24권3호
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• pp.389-392
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• 2003

• 한국재료학회지
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• 제13권12호
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• pp.785-790
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• 2003

We have synthesized some phosphors in the system $CaO-Y_2$$O_3$-$Al_2$$O_3$by combinatorial polymerized-complex method. Composition and synthetic temperature of phosphors in the library was screened from the emission intensities of individual samples under VUV excitation. In $Tb^{ 3＋}$-activated $CaO-Y_2$$O_3$-$Al_2$$O_3$, green phosphors showing good intensity were found to be X$O_3$$O_{7}$, CaYA1O$_4$, YA1O$_3$, $Y_3$$Al_{5}$$O_{12}$, $Y_4$$A1_2$$O_{9}$ .

• Bulletin of the Korean Chemical Society
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• 제28권9호
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• pp.1463-1466
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• 2007

Single phases of multi-component oxides films, ZrTiO4 and Ta2Zr6O17, could be synthesized by using the combinatorial approach through surface sol-gel route, coating the appropriate mole ratio of 100 mM zirconium butoxide, tantalum butoxide and titanium butoxide precursors on Pt/Ti/SiO2/Si (100) substrate, following pyrolysis at 450 oC, and annealing them at 770 oC. Both the films and bulks of ZrTiO4 and Ta2Zr6O17 showed very stable dielectric properties in temperature range, ?140 to 60 oC, and frequency range, 100 Hz to 1 MHz, promising their applications in wide range of temperatures and frequencies. The dielectric constants of the films were lower and a little more dependent on frequency than those of the bulks. The reduction of dielectric property in the film was mainly due to the interfacial effects that worked as series and parallel-connected capacitances toward the substantial film capacitance.