• Bulletin of the Korean Chemical Society
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• v.10 no.2
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• pp.161-167
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• 1989

The results of ab initio(MP2/6-31G) molecular orbital calculations of the dipole moment derivatives and gas phase IR intensities in chloromethanes are reported. The theoretical polar tensors are analyzed into the net charge, charge-flux, and overlap contributions. The charge-flux contribution was found to be dominant in the Cl atom polar tensor, while the net charge effect was the most prominent contribution for the H atom polar tensor. The Cl atom polar tensor appeared, in a good approximation, to be transferable among various chloro molecules. On the other hand, for the prediction of IR spectra of complex hydrocarbons containing chlorine atoms, some empirical adjustment of the H-atom polar tensor seemed to be made depending on the number of Cl atoms bound to the certain carbon atom.

• Proceedings of the Korean Fiber Society Conference
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• 2002.04a
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• pp.439-442
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• 2002

나일론 m형의 폴리아미드계 고분자의 경우 m의 수가 홀수일 때 N-H와 C=O 사이의 dipole 배열에 의하여 거대한 dipole moment가 나타나기 때문에 극성 결정구조를 나타내게 되며(1), 그 중에서도 특히 나일론 7과 11은 압전성을 나타낸다. 한편, 나일론 11[poly(undecanolactam)]은 $\alpha$, $\beta$, ν, $\delta$, $\delta$' 형과 같이 적어도 다섯 개의 결정형태를 갖는데[2-3], 이러한 여러 가지의 결정형태는 시료의 제조조건과 열처리 조건 등에 따라서 달라진다. (중략)

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.517-519
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• 2010

• Journal of the Korean Vacuum Society
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• v.5 no.4
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• pp.301-308
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• 1996

The heat of desorption and the work function change induced by nitrogen adsorption on the slepped tungstein surface plants, W(210) and W(310), are measured using the Field Electron Emission Microscope(FEM). The adsoption sites are predicted from the Thermal Desortion Spectra(TDS). The wirk function change of both W(210) and W(310) planes increase as increasing the nitrogen dose and saturates at the nitrogen dose about 5 Langmuir to 0.29 eV and 0.20 eV respectively. We find three adsorption site on each plane for the low dose range. The TDS result shows that the intensity of $\alpha_1$ state on W(310) is much stronger than that of $\alpha_1$ state on W(210), and the direction of nitrogen dipole moment adsorbed on the sites correspond to $\alpha_1$ and $\beta_2$ state on W(210) and W(310) planes are in the opposite direction to that of the equivalent states on W(100) plane. From this observation we can predict the relative atomic position in the z-direction (perpendicular direction to the surface) of nitrogen molecules/atoms adsorbed on these sites.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.10a
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• pp.11-14
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• 2000

This paper describes a thennally stimulated displacement current(TSDC) of polyamic acid alkylamine salts(PAAS) Langmuir-Blodgett(LB) films, which is a precursor of polyimide(PI). The TSDC measurements of PAAS LB film were performed from room temperature to about $250^{\circ}C$ and the temperature was increased at a rate of $0.2^{\circ}C/s$. This show that this is TSDC peaks at about $70^{\circ}C$ in the arachidic acid LB films, and at about $70^{\circ}C$ and $160^{\circ}C$ in the PAAS LB films. Results of this measurements indicate that one small peak at $70^{\circ}C$ is resulted from a softening of the alkyl group and the large peak at $160^{\circ}C$ is possibly due to dipole moment of C-O group in the PAAS molecule. We have calculated the vertical component of dipole moment of the P AAS LB film out of the TSDC curves. It shows that the dipole moment of PAAS LB film is about -40mD at $70^{\circ}C$ and about 200mD at $160^{\circ}C$ in the first measurement of TSDC. In the second measurement of TSDC of PAAS LB film after cooling down to room temperature, the TSDC peaks are almost disappeared.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.4 s.346
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• pp.44-51
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• 2006

In this paper, the resonance characteristics of zigzag wire dipole antennas are first analyzed by the method of moment(MOM) for shortening the space occupation length of straight wire dipole antenna Considering the shortening effect the integrated zigzag dipole antennas with the simplified microstrip feed are designed. Since the integration gives rise to discontinuities due to antenna line width with abrupt bend angles, the compensation by the chamfer is applied. Futhermore the integrated parasitic zigzag lines are properly attached to both sides of substrate for compensation of the effect of the dielectric substrate, hence improving the resonance characteristic. The design results at UHF and ISM band are verified with experiments.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.1
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• pp.109-121
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• 1999

In this paper, HF band LPDA(Log-periodic Dipole Antenna) and MLPDA(Modified Log-periodic Dipole Antenna) above lossy grounds were analyzed using moment method by considering the practical media parameter of lossy grounds, not assuming free space or perfect ground approximation. The radiation pattern and gain of LPDA and MLPDA as functions of frequency, antenna height from ground, and antenna tilt angle are presented, and the lossy ground effect on antennas characteristics are described. MLPDA was found to exhibit a smaller variation for gain and radiation pattern and a higher maximum beam direction relative to LPDA. It was shown that media parameter of lossy grounds and antenna height have a direct influence on the antenna gain of both LPDA and MLPDA.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.11
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• pp.1216-1224
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• 2003

In this paper Dual Band Log-Periodic Dipole Antenna(DLPDA), which can be used at the Cellular/IMT-2000 band, is proposed. The proposed antenna is composed of 2 of Log-Periodic Dipole Antenna(LPDA) and parasitic elements. To investigate the reliability of the proposed antenna, DLPDA is designed at the cellular/IMT-2000 band and analyzed by using the method of moment, Numerical results are compared with measured results. It is shown that although the antenna length is 70 cm, its radiation characteristics satisfied the design goals of gain, VSWR and beamwidth at the Cellular/IMT-2000 band. From these results, the proposed DLPDA is confirmed as the dual band antenna which can be used at the cellular/IMT-2000 band.

• Bulletin of the Korean Chemical Society
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• v.7 no.2
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• pp.129-136
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• 1986

The dipole moments for some coordination compounds with organic ligands have been calculated adopting the molecuar orbitals obtained from EHT calculation with modified technique. Adopting the molecular orbitals with the modified technique, the calculated dipole moments for all the coordination compounds with organic ligands give closer agreements with experimental values than those using the molecular orbitals obtained from EHT calculation. The calculated dipole moments suggest that $(C_2H_5)_2SO,\;(C_6H_5)_2SO,\;and\;(C_6H_5)_2SeO$ may have a trigonal planar structure and $(C_6H_5)_3AsO,\;and\;(C_6H_5)_3PBCl_3$ a square planar structure and $(C_2H_5)_2OZrCl_4$ may be distorted markedly. This work may also indicate that the modified technique is superior to the EHT calculation as far as the dipole moment calculation is concerned.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.234-236
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• 1993

Dielectric properties of low viscous silicone oils have been investigated as a function of frequency and The increase of polymerization degree was attributed to presence of Si-O-Si bonds and their increased dissociation factor. The application of the Clausius-Mosotti equation on the low viscous silicone oils, it has been previously assumed that the oils were dilute solutions of polar molecules. In the silicone oil the Si-o and O-Si bonds give dipole polarization. Simple relations have been found which dipole moment and activation energy as a function of number of Si atoms in the low viscous silicone oils.