• Korean Journal of Microbiology
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• v.35 no.2
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• pp.146-152
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• 1999

Acceplor reaction of glucosyltr~ansferase of Streptococcus ,SO~~-~IZLIS with f ~ ~ t o ~ y l o l i g o ~ a ~ ~ h a r i d e ~ was studied for the biosynthesis of novel olgisaccharides. First, bacilracin resistant mutants were selected by mutagenesis of Streptococcus sobrimis ATCC27351. Among these mutants 4 strains were selected by resistance to bacitracin and increase of glucosyltransferase. Acceptor reaction of maltose was analyzed by TLC and image analysis. There were differences in the specificity of the acceptor reaclion by Ule glucosylumsferase between mother strain (Streptococcus sobrinus ATCC2735) and bacitracin resistant mutants (Streptococcus sobrinus BR24C, Strepfococcus sobrinus CH-5). Molher strain did ilot show an acceptor reaction with fructosyloligosaccharides such as 1-keqtose and nystose. Acceptor reaction products of turailose and 1-kestose with glucosyltransferase (GW-S) of Streptococcus sobrini~s BR24C were TEX>\6^{3}$-$\alpha$-D-glucopyranosyl \3^{2}$-O-$\alpha$-D-fructose (glucose-fructose-glucose) and \6^{4}$-$\alpha$-D-glucopyranosyl \1^{3}$-$\beta$-D-~-h~ctofuranos~~ sucrose (glucose-glucosefructose- fructose). respectively These are novel oligosaccharides which can be produced only by enzymatic reaction.

• Bulletin of the Korean Chemical Society
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• v.35 no.4
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• pp.1098-1104
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• 2014

New electron deficient acceptor-acceptor-acceptor type of monomer unit composed of weak electron accepting benzimidazole and relatively strong electron accepting benzothiadiazole derivatives namely 4,7-bis(6-bromo-1-(2-ethylhexyl)-1H-benzo[d]imidazol-2-yl)benzo[c][1,2,5]thiadiazole (BBB) was synthesized. The Stille polycondensation of the newly synthesized BBB monomer with electron donating 2,6-bis(trimethyltin)-4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b']dithiophene (BDT) afforded donor-acceptor-acceptor-acceptor type of polymer namely 2,6-(4,8-bis(2-ethylhexyloxy)benzo[1,2-b:4,5-b']dithiophene)-alt-4,7-bis(1-(2-ethylhexyl)-1H-benzo[d]imidazol-2-yl)benzo[c][1,2,5]thiadiazole (PBDTBBB). The opto-electrical studies revealed that the absorption band of PBDTBBB appeared in the range of 300 nm-525 nm and its highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels were positioned at -5.18 eV and -2.84 eV, respectively. The power conversion efficiency (PCE) of the polymer solar cell (PSC) prepared from PBDTBBB:PC71BM (1:2 wt %) blend was 1.90%.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 1991.05a
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• pp.8-12
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• 1991

Biodegradation of carbon tetrachloride (CTC) in denitrifying and aerobic columns was investigated under various conditions of electron-acceptor and electron-donor availability. CTC removal increased when the electron-acceptor (nitrate) injection was stopped in the denitrifying column ; however, CTC removal decreased when electron donor (acetate) was deleted in the denitrifying and the aerobic column. Small fractions of the CTC removed appeared as chloroform, indicating that reductive dechlorination of CTC was occurring. The results from the denitrifying column support the hypothesis that CTC behave as an electron acceptor that competes for the pool of available electrons inside the bacterial cells.

• Microbiology and Biotechnology Letters
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• v.26 no.2
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• pp.179-186
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• 1998

Dextransucrase hyper-producing Leuconostoc mesenteroides B-512FMCM and dextransucrase constitutive mutants B-742CB and B-1355C catalyzed the transfer of glucose from sucrose to other carbohydrates which were present or were added to the reaction digests. When the acceptor was a maltose, gentiobiose, lactose or raffinose, there was produced a series of oligosaccharide acceptor products or single product based on the kinds of enzymes and reaction conditions. To obtain the quantitative information about the yield and the distribution of acceptor products and dextran two experimental parameters were studied: a) the ratio of acceptor to sucrose and b) the amount of enzyme at constant carbohydrate concentration (100 mM). As the amount of enzyme increased, the synthesis of acceptor products (of maltose or gentiobiose) increased, and the formation of dextran decreased. As the ratio of acceptor to sucrose increased, the amount of dextran and the number of acceptor-products decreased and the amount of acceptor-products increased. When maltose or gentiobiose was an acceptor, the glucose from sucrose was transferred to the C-6 hydroxyl group of the nonreducing-end glucose residue of accepters to give a homologous series of isomaltosyl dextrins. In case of lactose or raffinose, there was produced only one acceptor product from B-512FMCM dextransucrase reaction. In the lactose acceptor reaction, the glucose from sucrose was transferred to the C-2 hydroxyl of the reducing end glucose residue of lactose. To get a series of oligosaccharides from lactose or raffinose acceptor reaction we used B-742CB dextransucrase or B-1355C alternansucrase with 500 mM sucrose in reaction digest.

• Korean Journal of Materials Research
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• v.33 no.6
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• pp.236-241
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• 2023

Solar cells based on p-conjugated donor-acceptor (D-A) organic molecular systems are a promising alternative to conventional electrical energy generation. D-A molecular systems, which have a triphenylamine (TPA) moiety linked with a benzothiadiazole (BTD) moiety, open the potential development of new small molecule donors for bulk heterojunction (BHJ) solar cells. Here, a series of donor-acceptor-π-acceptor (D-A-π-A) small molecule donors (SMD) derived from triphenylamine (TPA) donor and benzothiadiazole (BTD) acceptor building blocks, were designed for BHJ organic solar cells. The small molecule donors SMD1-4 were studied using density functional theory (DFT) and time dependent-DFT (TDDFT) methods, to understand the effect of cyano and fluorine group functionalization on their properties. The effect of structure alteration by cyano and fluorine group functionalization on the optoelectronic properties, the calculated highest occupied molecular orbitals (HOMOs) and lowest unoccupied molecular orbitals (LUMOs) and the HOMO-LUMO gaps were theoretically explored. The V_oc (open-circuit photovoltage) and fill factor (FF) for SMD1-4 were obtained with a PC₇₁BM acceptor, which showed that these organic small molecules are potential small molecule donors for organic bulk heterojunction solar cells.

• Korean Journal of Materials Research
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• v.4 no.7
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• pp.798-807
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• 1994

The increase in the resistance of $BaTio_{3}$ with addition of Ca is attributed to the formation ofthe acceptor impurity by $CaCa^{2+}$" which substitutes Ti4+. However, some authors suggested that $Ca^{2+}$ can not substitute $Ti^{4+}$ because of its larger ionic radius. In this work, the existence of acceptor by Ca hasbeen studied through the high temperature equilibrium electrical conductivity of $BaTiO_{3}$ codoped with Caand Nb, where Ba/(Ti+Ca+Nb) was kept equal to unity. It was measured at $1000^{\circ}C$, and the oxygenpartial pressure was controlled between $10^{-15}$ ~ 1 atm. Changing the amount of added Ca and Nbresulted in the compensation effect between donor and acceptor, i.e., Nb was compensated by the acceptor.And through the defect chemical interpretation of the measured data, it was concluded that Ti canbe substitued with Ca. The existence of such acceptor was reaffirmated by ICTS(Isotherma1 CapacitanceTransient Spectroscopy) measurements.oscopy) measurements.

• Bulletin of the Korean Chemical Society
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• v.24 no.5
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• pp.569-572
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• 2003

The majority of dyes belong to the chromophoric class known as donor-acceptor systems. The essential structural feature of such systems is the presence of one or more electron donating groups conjugated to one or more electron withdrawing groups via an unsaturated bridge. The pyrazolin-5-one system is an effective electron acceptor residue, and can also act as a weak electron donor. In our experiments, the various symmetrical and unsymmetrical H-chromophores were synthesized in the indoxyl, imidazo[1,2-a]pyridin-2-one, pyrazolin-5-one, and pyridin-2,6-dione residues, resulting in cross-conjugated donor-acceptor systems. And the visible light absorption was then associated with the migration of electron density from the donor region of the molecule to the acceptor region. Also, it was useful to prepare related non-cross-conjugated donor acceptor chromophores by combining these residues with other electron donor or acceptor moieties. For convenience such chromophores are referred to as merocyanines.

• Bulletin of the Korean Chemical Society
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• v.33 no.6
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• pp.2040-2042
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• 2012

• Environmental Analysis Health and Toxicology
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• v.6 no.3_4
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• pp.149-154
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• 1991

Biodegradation of carbon tetrachloride (CTC) in denitrifying and aerobic columns was investigated under various conditions of electron-acceptor and electron-donor availability. CTC removal increased when the electron-acceptor (nitrate) injection was stopped in the denitrifying column; however, CTC remova1 decreased when electron donor (acetate) was deleted in the denitrifying and the aerobic column. Small fractions of the CTC removed appeared as chloroform, indicating that reductive dechlorination of CTC was occurring. The results from the denitrifying column support the hypothesis that CTC behaves as an electron acceptor that competes for the pool of available electrons inside the bacterial cells.

• Korean Journal of Materials Research
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• v.6 no.9
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• pp.950-958
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• 1996

저압 유기금속 화학증착법을 사용하여 AIGaInP층의 diethylzinc의 III족 원소(AO, Ga, In)에 대한 비와 성장온도 변화에 따른 Zn(acceptor)의 첨가 농도특성을 연구하였다. Diethylzinc의 III족 원소(AI, Ga, In)비를 0.4에서 2.0까지 변화시켜 본 결과 0.85일 때 가장 높은 acceptor 농도를 가졌으며, 성장온도를 69$0^{\circ}C$에서 80$0^{\circ}C$까지 변화시킨 결과 성장온도에 대한 변화는 69$0^{\circ}C$-73$0^{\circ}C$일 때 온도가 증가함에 따라 acceptor농도는 커졌으며, 그 이상에서는 감소하였다. 또한, 성장속도가 빠를수록 높은 acceptor 농도를 가지게 되어 3.3$\mu\textrm{m}$/hr의 성장속도일 때 8x1017/㎤의 가장 높은 acceptor 농도를 얻을수 있다.