• Bulletin of the Korean Chemical Society
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• v.30 no.4
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• pp.787-790
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• 2009

The predictions of the radical reaction sites for phenol, 2-, 3- and 4-chlorophenols (CPs) and 4-chloronitrobenzene (CNB) were studied by atomic charge distribution calculations. The atomic charge distributions on each atom of these molecules were obtained using the CHelpG and MK (Merz-Kollman/Singh) methods with the optimized structural parameters determined by DFT calculation at the level of BLYP/6-311++G(d,p). By comparing the experimentally obtained hydroxyl addition site(s) and the calculated atomic charges on carbon atoms of phenol and CPs, we found that hydroxyl substitution by oxidation reaction mainly occurred to the carbon(s) with high atomic charges. With these results, we were easily able to predict the position(s) of the ·OH reaction site(s) of phenol, CPs and CNB through atomic charge distribution calculations.

• Journal of the Korean Applied Science and Technology
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• v.33 no.3
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• pp.492-497
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• 2016

The intermediate product resulting from the radical degradation experiment of PCE and the atomic charge gained through Gaussian03W were compared against each other. The result was that the ratio of PCE radical degradation was almost 98% or higher after the 9 hr point in reaction time. The reaction speed constant was $0.16hr^{-1}$ and it followed the first reaction. We could see that at each location of the PCE molecule, dechlorination happened at a point where the negative atomic charge was the greatest. Moreover, the intermediate product of PCE radical degradation that was confirmed in the experiment and literature coincided exactly with the intermediate product in the atomic charge calculation. Therefore, when the atomic charge is calculated, the radical degradation pathway of the organic chlorine compound could be forecast.

• Journal of Radiation Protection and Research
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• v.35 no.2
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• pp.81-84
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• 2010

A CSA(Charge Sensitive Amplifier) was designed and fabricated for application in a radiation detection system based on a semiconductor detector such as Si, SiC, CdZnTe and etc.. A fabricated hybrid.type CSA was evaluated by comparison with a commercially available CSA. A comparison was performed by using calculation of ENC (Equivalent Noise Charge) and by using energy resolutions of fabricated radiation detectors based on Si. In energy resolution comparison, a fabricated CSA showed almost the same performance compared with a commercial one. In this study, feasibility of a fabricated CSA was discussed.

• Bulletin of the Korean Chemical Society
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• v.34 no.1
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• pp.299-302
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• 2013

• Journal of the Korean Chemical Society
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• v.56 no.2
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• pp.195-200
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• 2012

In this study we present a new approach for computing the partial atomic charge derived from the wavefunctions of molecules. This charge, which we call the "y_charge", was calculated by taking into account the energy level and orbital populations in each molecular orbital (MO). The charge calculations were performed in the software, which was developed by us, developed using the C# programming language. Partial atomic charges cannot be calculated directly from quantum mechanics. According to a partitioning function, the electron density of constituent molecular atoms depends on the electrostatic attraction field of the nucleus. Taking into account the Boltzmann population of each MO as a function of its energy and temperature we obtain a formula of partial charges.

• Journal of the Korean Chemical Society
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• v.11 no.4
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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.

• Journal of Photoscience
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• v.10 no.1
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• pp.105-119
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• 2003

Fullerenes, $C_{60}$ and $C_{70}$, display interesting physicochemical properties in solutions, especially due to their unique chemical structures and their good electron accepting abilities. Solubility of fullerenes in different organic solvents and their unusual solvatochromic behavior, the ability of the fullerenes to form aggregates in solutions, and their electron transfer and charge transfer interactions with variety of electron donors, are the subjects of extensive research activities for more than one decade. Many research groups including ours have contributed substantially in the understanding of the solvatochromism, aggregation behavior, and the photoinduced electron transfer and charge transfer chemistry of fullerenes, in condensed phase. Present article is aimed to summarize the important results reported on the above aspects of fullerenes, subsequent to the earlier report from our group (D.K. Palit and J.P. Mittal, Full. Sci. & Tech. 3, 1995, 643-659).)., 643-659)..

• Journal of the Korean Chemical Society
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• v.11 no.4
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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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• 1999.07a
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• pp.171-171
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• 1999

We studied the charge redistribution in the Pt-M (M=Cu, Co) alloys by X-ray Absorption Near Edge Spectroscopy(XANES) and X-ray Photoelectron Spectroscopy(XPS). These analysis tools provide us information about the charge transfer in the valence band of intermetallic bonding. The samples were prepared by arc-melting method. After annealing this samples in vacuum for several hours, we cold get the ordered samples, which were confirmed with XRD analysis. the core and valence level energy shift in these system were investigated by Mg $K\alpha$(1253.6eV) x-ray source for Pt-Co alloys and monochromatized Al $K\alpha$ (1486.6eV) for Pt-Cu alloys. Pt L2, L3-edge, and Cu, Co K-edge XANES spectra were measured with the total electron-yield mode detector at the 3Cl beam line of the PLS (Pohang light source0. from the changes of White line (WL) area and the core level shifts of the each metal sites, we can obtain the information about the electrons participating in the intermetallic bonding of the Pt-Cu and Pt-Co alloys.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.21 no.5
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• pp.885-892
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• 2017

In this paper, we proposed a novel crowbar circuit for high-speed discharge charge switching to solve discharge charge-time delay of supply voltage in the conventional crowbar circuit. The proposed circuit is designed to increase the charge-speed after high-speed discharge of supply voltage, thereby reducing the time exposed to radiation damage and, the normal operation time of electronic system after passing the pulse radiation. The simulation of the discharge charge-times before the implement of the hardware is conducted using Cadence's pspice tool, and DUT (Device Under Test) board is fabricated in the device level. The comparison measurement of the crowbar circuits is performed on the satellite-electronic device for 24V. As the result, we confirmed the high-speed function of the proposed circuit by improvement of the discharge-speed 96.8% and the charge-speed 27.3% as compared with the conventional circuit.