• Applied Biological Chemistry
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• 제17권2호
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• pp.143-148
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• 1974

The interaction of the carcinogenic mycotoxin, Aflatoxin $B_1$, with the electron-donating molecule, benzene, was studied spectrophotometrically. The formation of charge-transfer complex between Aflatoxin $B_1$ and benzene in the presence of zinc chloride was observed and the apparent equilibrium constant of this charge-transfer complex was found to be 0.198 (liter $mole^{-1}$). It is assumed that, as the result of this study, some charge-transfer complexes could be formed between the weak electron-accepting Aflatoxin $B_1$ and strong electron-donating molecules, and the spectral changes occurred in the binding of Aflatoxin $B_1$ with proteins or DNA is attributed to the existence of charge-transfer type interaction.

• Journal of the Korean Chemical Society
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• 제11권4호
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• pp.121-125
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• 1967

The formation of a charge transfer complex between various amines and organic halogen compounds was closely investigated. A mixture of amine (piperidine, pyridine, diethylamine, ethylamine, triethylamine and triethanolamine) and organic halides(carbon tetrachloride and chloroform) was checked for its UV absorption spectrum in presence of n-hexane solvent. A red shift was observed. The formation of charge transfer complex was observed in the case of triethylamine and diethylamine, whereas the formation of contact complex was distinct in case of piperidine. The relation between the nucleophilicity of amines and their tendency of forming charge transfer complex was discussed.

• Bulletin of the Korean Chemical Society
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• 제28권4호
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• pp.607-612
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• 2007

Relationship between charge transfer mechanism and quantum coherence has been investigated using a realtime quantum dynamics approach. In the on-the-fly filtered propagator functional path integral simulation, by separating paths that belong to different mechanisms and by integrating contributions of correspondingly sorted paths, it was possible to accurately obtain quantitative contribution of different transport mechanisms. For a 5'-GAGGG-3' DNA sequence, we analyze charge transfer processes quantitatively such that the governing mechanism alters from coherent to incoherent charge transfer with respect to the friction strength arising from dissipative environments. Although the short DNA sequence requires substantially strong dissipation for completely incoherent hopping transfer mechanism, even a weak system-environment interaction markedly destroys the coherence within the quantum mechanical system and the charge transfer dynamics becomes incoherent to some degree. Based on the forward-backward path deviation analysis, the coherence variation depending on the environment is investigated numerically.

• Journal of the Korean Chemical Society
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• 제11권4호
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• pp.126-131
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• 1967

Various amines (Triethylamine, Diethylamine, Dimethylaniline, Pyridine and Diphenylamine) and electron acceptors (Carbontetrachloride, iodine monochloride and iodine) were reacted in the hexane solvent system to form a charge transfer complex in each case. The tendency of forming a charge transfer complex by these electron acceptors was proportional to the basicity of amines and the different type of complex was formed as the polarity of electron donor had markedly changed, which were identified by ultraviolet spectrophotometry. A correlation between the formation of complex and the basicity of amine and the polarity of electron acceptor was discussed.

• Proceedings of the Korean Vacuum Society Conference
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.186.1-186.1
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• 2014

Graphene, which is a 2-dimensional carbon material, has been attracting much interest due to its unique properties and potential applications. So far, many interesting experimental and theoretical works have been done concerning the electronic properties of graphene on various substrates. Especially, there are many experimental reports about doping in graphene which is caused by interaction between graphene and its supporting substrates. Here, we report the study of charge transfer between graphene and oxide substrates using density functional theory (DFT) calculations. In this study, we have investigated the charge transfer related with graphene considering various oxide substrates such as SiO2(0001) and MgO(111). Details in charge transfer between graphene and oxides are analyzed in terms of charge density difference, band structure and work function.

• Bulletin of the Korean Chemical Society
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• 제6권1호
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• pp.23-29
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• 1985

The charge-transfer complexing properties of 1-methyl nicotinamide (MNA), an acceptor, and adenine, a donor, were investigated in water and SDS micellar solutions in relation to the intramolecular interaction in nicotinamide adenine dinucleotide ($NAD^+$). The spectral and thermodynamic parameters of MNA-indole and methyl viologen-adenine complex formations were determined, and the data were utilized to evaluate the charge-transfer abilities of MNA and adenine. The electron affinity of nicotinamide was estimated to be 0.28 eV from charge-transfer energy $of{\sim}300$ nm for MNA-indole. The large enhancement of MNA-indole complexation in SDS solutions by entropy effect was attributed to hydrophobic nature of indole. The complex between adenine and methyl viologen showed an absorption band peaked near 360 nm. The ionization potential of adenine was evaluated to be 8.28 eV from this. The much smaller enhancement of charge-transfer interaction involving adenine than that of indole in SDS solutions was attributed to weaker hydrophobic nature of the donor. The charge-transfer energy of 4.41 eV (280 nm) was estimated for nicotinamide-adenine complex. The spectral behaviors of $NAD^+$ were accounted to the presence of intramolecular interaction in $NAD^+$, which is only slightly enhanced in SDS solutions. The replacement of nicotinamide-adenine interaction in $NAD^+$ by intermolecular nicotinamide-indole interaction in enzyme bound $NAD^+$, and guiding role of adenine moiety in $NAD^+$ were discussed.

• Journal of the Institute of Electronics Engineers of Korea SC
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• 제48권3호
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• pp.53-59
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• 2011

Charge transfer through DNA oligonucleotides has been investigated for potential applications of DNA into molecular electrooptic switching devices. Electrons were injected using gold electrode probes where DNA oligomers were adsorbed that are separated in medium. The results show that increased adsorption of DNA reduces the ionization current due to the combined effect of charge transfer through DNA and surface-limited charge transport. The probe-based charge injection was extended to examine the capability of extinguishing fluorescence of Cy3 dye molecules attached to DNA. It is expected that the results may be employed to implementing a novel electrooptic switching device based on DNA molecules.

• Journal of the Institute of Electronics Engineers of Korea SD
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• 제45권4호
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• pp.137-145
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• 2008

In this paper, novel CMOS charge pump having NMOS and PMOS transfer switches and a bulk-pumping circuit has been proposed. The NMOS and PMOS transfer switches allow the charge pump to improve the current-driving capability at the output. The bulk-pumping circuit effectively solves the bulk forward problem of the charge pump. To verify the effectiveness, the proposed charge pump was designed using a 80-nm CMOS process. The comparison results indicate that the proposed charge pump enhances the current-driving capability by more than 47% with pumping speed improved by 9%, as compared to conventional charge pumps having either NMOS or PMOS transfer switch. They also indicate that the charge pump reduces the worst-case forward bias of p-type bulk by more than 24%, effectively solving the forward current problem.

• Journal of Mechanical Science and Technology
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• 제17권3호
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• pp.422-428
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• 2003

This study concerns the performance of the heat transfer of the thermosyphons having 60, 70, 80. 90 axial internal low-fins in which boiling and condensation occurr. Water, HCFC-141b and CFC-11 have been used as the working fluids. The operating temperature, the liquid charge ratio and the inclination angle of thermosyphons have been used as the experimental parameters. The heat flux and heat transfer coefficient at the condenser are estimated from experimental results. The experimental results have been assessed and compared with existing theories. As a result of the experimental investigation, it was found that the maximum heat flow rate in the thermosyphons is dependent upon the liquid charge ratio and inclination angle. A relatively high rate of heat transfer has been achieved by the thermosyphon with axial internal low-fins. The inclination of a thermosyphon has a notable influence on the condensation. In addition, the overall heat transfer coefficients and the characteristics at the operating temperature are obtained for the practical applications.

• Bulletin of the Korean Chemical Society
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• 제29권5호
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• pp.948-952
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• 2008

The molecular association of acceptors with electron donors is studied in the highly-polar solvent $CH_3CN$. Tetracyanoquinodimethane (TCNQ) forms a stable charge-transfer complex with donor molecules such as 4- aminobiphenyl (4-AB), benzidine (BD) and 2-aminobiphenyl (2-AB) with high association constants. The complexes of TCNQ with 4-AB or BD show new absorption bands at around 800 and 500 nm, which can be identified as reduced $TCNQ^{{\bullet}-}$ and $TCNQ^{2-}$ species, respectively. These bands grow quickly upon photoirradiation, implying that the charge-transfer complexes are easily formed in an excited state. Conversely, a small spectral manifestation of the charge transfer was observed in the case of 2-AB complex. It is demonstrated that the structural orientation between the geminate ion pairs could play an important role in building a stable complex.