• Proceedings of the Korean Society of Marine Engineers Conference
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• 2000.11a
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• pp.43-49
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• 2000

Heat transfer characteristics of self oscillating heat pipe were experimentally investigated for the effect of fill charge ratios and heat loads. The heat pipe used for this study is made of copper capillary, has 0.002m internal diameter, a 0.34m length in one turn and consists of 19 turns. Heating and cooling section each have a length of 70mm. Water was used as working fluid inside heat pipe. As the experimental results, the self oscillating heat pipe was operated by self-exited oscillation and circulation of working fluid and the oscillation within the self oscillating heat pipe assumed chaotic behavior.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.458-458
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• 2011

Graphene, a single atomic layer of sp2-bonded carbon, shows substantial potential for various applications. Chemical manipulation of its electronic properties will be of great importance. In this study, we have investigated interaction between graphene and organic molecular layer of tetrafluorotetracyanoquinodimethane (F4-TCNQ), a strong electron acceptor. F4-TCNQ films of varying thickness were evaporated onto graphene mechanically exfoliated on SiO2/Si substrates. F4-TCNQ molecules increase the frequencies of Raman G and 2D bands of graphene while decreasing the linewidth of G band and 2D/G intensity ratio, which is consistent with increase of hole density in graphene. These results exemplify the possibility of chemical tuning of electronic properties of graphene.

• Analytical Science and Technology
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• v.8 no.4
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• pp.603-610
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• 1995

The charge transfer rate in polypyrrole(PPy) electropolymerized within poly(acrylonitrile-co-butadiene)(PAB) was compared with that in PPy deposited Pt electrodes by using cyclic voltammetry, chronoamperometry, and chronopotentiometry in acetonitrile. For both electrodes anodic and cathodic peak currents were proportional to scan rates below 100 mV/sec, but to square root of scan rates beyond 200 mV/sec. The apparent diffusion coefficient of $ClO{_4}^-$ in the PPy/PAB composite is estimated to be 1.6 times larger than that in PPy. The PPy films composited within PAB layer showed higher anodic and cathodic currents and possessed faster charging-discharging process and larger capacity.

• YAKHAK HOEJI
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• v.43 no.4
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• pp.437-441
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• 1999

Enoxacin[1-ethyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-\piperazinyl)-1,8-naphthyridine-3-carboxylic acid, ENX] is a new quinolone antibacterial agent. The method is based on the highly colored charge-transfer complex formation of this drug as a $\pi$-electron donor with 7,7,8,8-tetracyanoquinodimethane(TCNQ) or chloranil(CL) as $\pi$-acceptors. The colored products were measured spectrophotometrically at 842 nm and 552 nm for TCNQ and CL, respectively. The different experimental conditions are optimized. The linearities for TCNQ and CL were $1.6{\;}\mu\textrm{g}/mL~32{\;}\mu\textrm{g}/mL$ and $6.4{\;}\mu\textrm{g}/mL~160{\;}\mu\textrm{g}/mL$, respectively and colors were produced in non-aqueous media. This report describes a simple and ra\pid method for the analysis of enoxacin.

• YAKHAK HOEJI
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• v.53 no.6
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• pp.342-350
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• 2009

The interaction of cadmium (II) ion with quercetin and (+)-catechin was investigated in aqueous solution at various pH. The flavonoid/cadmium stochiometries for cadmium (II) binding to quercetin and (+)-catechin have been determined by UV-vis spectroscopy. 1 : 1 Cd (II)-Flavonoid complex had a maximum absorbance and showed the bathochromic shift of the long-wavelength band of the UV-vis spectra in the alkaline pH, that occurs upon complexation, due to a ligandto-metal charge transfer. These results suggest that Cd (II)-flavonoid complex has the optimal condition of chelation in 0.2 M $NH_3$ - 0.2 M $NH_4Cl$ (pH 8.0) solution.

• Bulletin of the Korean Chemical Society
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• v.35 no.1
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• pp.135-140
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• 2014

A bent-shape triazolyl derivative was synthesized via click chemistry, and its photophysical property was investigated in various solvents. In contrast to the invisible ultraviolet emission of other solutions, the chloroform solution exhibited a blue light emission at 460 nm. Furthermore, the blue fluorescence intensified as the UV exposure time at 365 nm increased. On the basis of $^1H$-NMR, pH paper, and acid-addition studies, we confirmed that chloroform was decomposed into HCl with the aid of the triazolyl derivative. The density functional theory calculations suggested that the eye-detectable blue fluorescence was attributed to an intramolecular charge transfer process of the protonated triazolyl derivative in the chloroform solution.

• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1535-1542
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• 2010

Spectrophotometric micro determination of allopurinol (ALP) via charge-transfer formation is described. This includes the utility of some $\pi$-acceptors such as 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and 3,6-dichloro-2,5-dihydroxy-p-benzoquinone (p-CLA) for estimation of ALP drug (act as $\grave{e}$-donor). These reactions are applied for determination of ALP in its pharmaceutical preparations coming from different companies. Elucidation of the chemical structure of the solid CT complexes formed via reaction between drugs under study and $\pi$-acceptors, using elemental analyses (C, H, N), I. R., $^1H$ NMR and mass spectrometry.

• Journal of Power Electronics
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• v.13 no.1
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• pp.51-58
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• 2013

This paper proposes the power conversion mechanism of a bailer-charge-transfer zero-current-switching (CT-ZCS) circuit. The operation modes are analyzed and researched using state trajectory equations. The topology of CT-ZCS based on soft-switching inverters offers some merits such as: tracking the input reference signal dynamically, bearing load shock and short circuit, multiplying inverter N+1 redundancy parallel, coordinating power balance for easy control, and soft-switching commutation for high efficiency and large capacity. These advantages are distinctive from conventional inverter topologies and are especially demanded in AC drives: new energy generation and grid, distributed generation systems, switching power amplifier, active power filter, and reactive power compensation and so on. Prototype is manufactured and experiment results show the feasibility and dynamic voltage-tracking characteristics of the topology.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.4
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• pp.161-164
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• 2005

Viologen has been extensively investigated in the paper because their well-behaved electrochemistry has led to their use in a variety of theses, including the electron acceptor for the electric charge delivery mediation of the devices. It was formed monolayer in QCM by self-assembly method. We could know the adsorbed mass of viologen molecules from the frequency shift. We calculated that the adsorbed mass was about 196 [$ng/cm^2$]. We studied the electron transfer property of viologen by the cyclic voltammetry among the electrochemical process so we changed an anion like 0.1 M $NaClO_4$ and $Na_3PO_4$ electrolyte solution and investigated the interrelationship between scan rate and peak current when scan rates were increased twice.

• Bulletin of the Korean Chemical Society
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• v.25 no.1
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• pp.45-50
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• 2004

$Cu^{II}$-complexes of N-salicylideneaniline and its derivatives were not light sensitive in most solvents such as acetonitrile. A photo-decomposition occurred upon irradiation in halocarbon solvents such as $CHCl_3$. It has been suggested that such photoreactivity is attributed to the reactivity of charge-transfer to solvent (CTTS) excited state attained upon irradiation. A mechanism has been proposed to account for the results obtained. The complexes have been thermally analysed in nitrogen and static air using thermogravimetry (TG) and derivative thermogravimetry (DTG). The thermal degradation of the complexes proceeds in two or three stages. The kinetic parameters obtained from the Coats-Redfern and Horowitz-Metzger equations show the kinetic compensation effect.