• Journal of Photoscience
• /
• 제9권1호
• /
• pp.17-22
• /
• 2002

Studies have been conducted to explore photoaddition reactions of N-methylthiophthalimide with $\alpha$-silyl-n-electron donors Et$_2$NCH$_2$SiMe$_3$, n-PrSCH$_2$SiMe$_3$ and EtOCH$_2$SiMe$_3$. Photoaddition of $\alpha$-silyl amine Et$_2$NCH$_2$SiMe$_3$ to N-methylthiophthalimide occurs in $CH_3$CN and benzene to produce non-silicon containing adduct in which thiophthalimide thione carbon is bonded to $\alpha$-carbon of $\alpha$-silyl amine in place of the trimethylsilyl group. In contrast, photoaddition of EtOCH$_2$SiMe$_3$ to N-methylthiophthalimide generates two diastereomeric adducts in which thiophthalimide thione carbon is connected to $\alpha$-carbon of $\alpha$-silyl ether in place of u-hydrogen. Based on a consideration of the oxidation potentials of u-silyl-n-electron donors and the nature of photoadducts, mechanism for these photoadditions involving single electron transfer(SET) -desilylation and H atom abstraction pathways are proposed.

• 한국지하수토양환경학회:학술대회논문집
• /
• 한국지하수토양환경학회 2003년도 추계학술발표회
• /
• pp.391-394
• /
• 2003

The applicability of in situ microbial filter or biobarrier technology for the remediation of soil and groundwater contaminated with chlorinated solvents was investigated. The efficiency and rates of reductive dechlorination of chlorinated solvents are known to be highly dependent on hydrogen concentration. In this study, the effect of electron donors on the reductive dechlorination of PCE was investigated using vermicompost (worm casting) and peat as permeable reactive barrier medium The effect of organic acids (lactate, butyrate and benzoate), yeast extract and vitamin $B_{l2}$ on the reductive dechlorination was investigated. Compared to the control (no electron donor added), addition of electron donors stimulated the dechlorinated rate. Among the electron donor treatments, lactate/benzoate amendment exhibited the highest dechlorination rate. Since vermicompost and peat are inexpensive and biodegradable and have high sorption capacity, they could be successfully used as biobarrier media, especially when electron donors (for example, lactate/benzoate) are added.d.

• Coupled systems mechanics
• /
• 제6권1호
• /
• pp.75-96
• /
• 2017

As electron donor/acceptor materials for organic photovoltaic cells, small-molecules donors/acceptor are attracting more and more attention. In this work, we investigated the electronic structures, electrochemical properties, and charge carrier transport properties of four recently-synthesized small-molecule donors/acceptor, namely, DPDCPB (A), DPDCTB (B), DTDCPB (A1), and DTDCTB (B1), by a series of ab initio calculations. The calculations look into the electronic structure of singly oxidized and reduced molecules, the first anodic and cathodic potentials, and the electrochemical gaps. Results of our calculations were in accord with those from experiments. Using Marcus theory, we also computed the reorganization energies of hole/electron hoppings, as well as hole/electron transfer integrals of multiple possible molecular dimer configurations. Our calculations indicated that the electron/hole transport properties are very sensitive to the relative separations/orientations between neighboring molecules. Due to high reorganization energies for electron hopping, the hole mobilities in the molecular crystals are at least an order of magnitude higher than the electron mobilities.

• Biotechnology and Bioprocess Engineering:BBE
• /
• 제7권2호
• /
• pp.112-116
• /
• 2002

Effects of artificial electron donors to deliver reducing power on enzymic denitrification were investigated using nitrate reductase and nitrite reductase obtained from Ochrobactrum antroyi. The activity of nitrite reductase in the soluble portion was almost the same as that in the precipitated portion of the cell extract. Nitrate removal efficiency was higher with benzyl viologen than with methyl viologen or NADH as an artificial electron donor. The turn-over numbers of nitrate and nitrite reductase were 14.1 and 1.9 umol of nitrogen reduced/min$.$mg cell extracts, respectively when benzyl viologen was used as an electron donor.

• Journal of Microbiology and Biotechnology
• /
• 제6권4호
• /
• pp.232-237
• /
• 1996

Growth yield of Desulfovibrio desulfuricans M6 was measured using different substrates. The cell yield of fermentative growth on pyruvate was 6.22 g cell $mol^{-l}$ pyruvate. Since 1 ATP is available from substrate-level phosphorylation from the oxidation of pyruvate to acetate, $Y_{ATP}$ of the bacterium should be the same as $Y_{pyruvate}$ (6.22 g cell $mol^{-l}$ ATP). The cell yields of the bacterium on different electron donors were measured with sulfate as the electron acceptor. Cell yields on lactate, pyruvate and $H_2$ were 9.39, 13.76 and 8.45 g cell $mol^{-l}$ substrate, respectively. From these figures ATP available from electron-transport phosphorylation (ETP) of the electron donors used was calculated. ATP produced by ETP of each electron donnor were 1.71 from pyruvate, 1.51 from lactate and 1.76 from $H_2$. These values show that electrons from the oxidation of lactate to pyruvate are consumed to reduce sulfate through a reverse electron transport mechanism requiring 0.2 ATP for each pair of electrons. Based on these results, discussions are made on the electron transport mechanism in the bacterium.

• 대한화학회지
• /
• 제37권11호
• /
• pp.929-936
• /
• 1993

몇 가지의 전자주개와 하나의 전자받개와의 전하이동 착물에 관한 연구는 세 종류의 용매 즉, 염화에틸렌, 염화메틸렌 그리고 클로로포름하에서 그리고 16, 19, 22, 25$^{\circ}$C의 온도범위에서 자외선 분광광도계로서 최대흡수파장 및 흡광도를 측정하였다. 그리고 이 연구는 전자주개로서는 1,2,3,4-테트라하이드로카바졸, 2-메틸, 3-메틸 그리고 3-에킬사수소카바졸을 선택하였으며 전자받개로는 클로라닐을 이용하였다. 이 전하이동 착물은 1:1 몰비로 형성되었으며, 최대흡광도 및 형성상수는 용매의 극성과 온도에 따라 감소하였다. 열역학적 양으로서 용매의 극성과 온도가 형성상수에 미치는 영향을 논하였으며, 또한 몇 가지의 전자주개들의 전자 및 입체효과가 형성상수에 미치는 효과를 고찰하였다.

• Bulletin of the Korean Chemical Society
• /
• 제18권2호
• /
• pp.151-155
• /
• 1997

Stereochemical course of the reductive decyanation of two stereoisomeric 4-t-butyl-1-phenylcyclohexanecarbonitriles 3 and 4 using solvated electron has been studied. While sodium-mediated reactions of both 3 and 4 in the presence of alcohols give the same ratio, 1.5 : 1, in favor of the thermodynamically more stable product 5 over the other one 6, the ratios obtained from the potassium-mediated process are found to be very sensitive to the kind of H-donors. When reactions are performed without H-donors, 5 is only obtained from the experiments with both stereoisomers irrespective of the metal species.

• 동아시아식생활학회지
• /
• 제7권3호
• /
• pp.325-329
• /
• 1997

본 세균의 성장과 수소생성을 위한 최적온도는 30-35$^{\circ}C$ 이었고 최적 pH는 7.0 부근이었다. 이 광합성 세균의 수소발생을 위한 전자전달계의 유기화합물은 포도당 또는 과당과 같은 당류와 malate 혹은 pyruvate 같은 유기산이 효율적임이 밝혀졌다. 이 결과는 Rhodobacter sphaeroides KS56이 전자전달계로서 여러종류의 환원성 탄수화물을 이용할 수 있음을 나타낸다.

• 한국재료학회지
• /
• 제31권6호
• /
• pp.320-324
• /
• 2021

Effects of growth variables and post-growth annealing on the optical, structural and electrical properties of magnetron-sputtered Ga_0.04Mg_0.10Zn_0.86O films are characterized in detail. It is observed that films grown from pure oxygen plasma showed high resistivity, ~10² Ω·cm, whereas films grown in Ar plasma showed much lower resistivity, 2.0 × 10^-2 ~ 1.0 × 10^-1 Ω·cm. Post-growth annealing significantly improved the electrical resistivity, to 4.3 ~ 9.0 × 10^-3 Ω·cm for the vacuum annealed samples and to 1.3 ~ 3.0 × 10^-3 Ω·cm for the films annealed in Zn vapor. It is proposed that these phenomena may be attributed to the improved crystalline quality and to changes in the defect chemistry. It is suggested that growth within oxygen environments leads to suppression of oxygen vacancy (Vo) donors and formation of Zn vacancy (V_Zn) acceptors, resulting in highly resistive films. After annealing treatment, the activation of Ga donors is enhanced, Vo donors are annihilated, and crystalline quality is improved, increasing the electron mobility and the concentration. After annealing in Zn vapor, Zn interstitial donors are introduced, further increasing the electron concentration.

• 미생물학회지
• /
• 제39권3호
• /
• pp.175-180
• /
• 2003

Shewanella putrefaciens DK-1은 그람음성, 통성 혐기성 세균으로 $NO_{3}$, Fe(III), Mn(IV), humic acid와 같은 다양한 전자수용체를 이용한다. S. putrefaciens DK-1의 전자공여체의 이용능력은 제한적이며, lactate나 formate는 좋은 전자공여체로 이용되지만 acetate나 toluene은 이용하지 못하였다. 다양한 전자수용체간의 경쟁을 살펴보기 위해 전자수용체로 Fe(III)와 같이 $NO_{3}^{-}$, $NO_{2}^{-}$를 넣어 주었을 매 Fe(III)의 환원은 저해되었다. 또한 5. putrefaciens DK-1은 전자수용체로 토양에 광범위하게 존재하는 humic acid를 이용하였으며, 환원된 humic acid는 질산염에 의해서 다시 산화되었다. Fe(III) 환원능이 있는 환경 시료를 이용하여 탄소, 질소, 인과 같은 제한 요인이 Fe(III) 환원세균의 활성에 미치는 효과를 조사하였다. 천호지의 저질토와 대호의 농토에 각각 탄소원, 질소원, 인을 첨가해 주었을 경우 S. putrefaciens DK-1과 탄소원을 동시에 첨가해 주었을 때 가장 높은 철 환원능을 보여주었다.