• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.17-19
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• 2003

Electric arc furnace has consumed plenty of power. Hence electric arc furnace can be expected to use for demand side management. When electric arc furnace use for demand side management, electric arc furnace frequently occur a starting and a stop. Electric arc furnace irregularity change consumption of power. Due to character of time-varing and non-linear, electirc arc furnace has a problem with voltage quality(flicker, harmonics). Producted harmonic in electric art furnace is different any harmonic source because of electric arc furnace peculiar operating. Accordingly, analysis for generated harmonic in electric arc furnace operating is demanded. This paper analyze effect of harmonic by arc furnace operating.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.3
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• pp.434-440
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• 2010

In this paper, we define generalized induced linguistic aggregation operator called generalized induced linguistic ordered weighted harmonic mean(GILOWHM) operator. Each object processed by this operator consists of three components, where the first component represents the importance degree or character of the second component, and the second component isused to induce an ordering, through the first component, over the third components which are linguistic variables and then aggregated. It is shown that the induced linguistic ordered weighted harmonic mean(ILOWHM) operator and linguistic ordered weighted harmonic mean(LOWHM) operator are the special cases of the GILOWHM operator. Based on the GILOWHM and LWHM operators, we develop an approach to group decision making with linguistic preference relations. Finally, a numerical example is used to illustrate the applicability of the proposed approach.

• Proceedings of the Korea Concrete Institute Conference
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• 1998.04a
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• pp.63-68
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• 1998

The fluidity of high flowing concrete can be affected by numerous parameters which characterize either the cement of the admixture. The reactivity of a cement as determined by its chemical composition(especially its $C_3$A content), its fineness and its content in sulfates and alkalies obviously plays a key role in rheology of high flowing concrete in fresh state. Specific properties of high range water reducing AE agent used to enhance the workability of high flowing concrete also exert important influence. The purpose of this experimental study is to investigate and analyze the effect of cement and high range water reducing AE agent in fluidity, setting, compressive strength of high flowing concrete. As a result, we found that fluidity of high flowing concrete is affected greatly by kind of cement and high range water reducing AE agent, also, there is harmonic character between high belite cement and polycarbonic acid high range water reducing AE agent.

• Bulletin of the Korean Chemical Society
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• v.29 no.1
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• pp.181-186
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• 2008

2,5-Di-(2'-hydroxyethoxy)-4'-nitrostilbene (3) was prepared and polycondensed with terephthaloyl chloride, adipoyl chloride, and sebacoyl chloride to yield novel T-type polyesters (4-6) containing the NLO-chromophores dioxynitrostilbenyl groups, which constituted parts of the polymer backbones. Polymers 4-6 are soluble in common organic solvents such as acetone and N,N-dimethylformamide. They showed thermal stability up to 260 oC in thermogravimetric analysis with glass-transition temperatures obtained from differential scanning calorimetry in the range 90-95 oC. The second harmonic generation (SHG) coefficients (d33) of poled polymer films at the 1064 nm fundamental wavelength were around 1.42 ´ 10-9 esu. The dipole alignment exhibited high thermal stability up to 5 oC higher than glass-transition temperature (Tg), and there was no SHG decay below 100 oC due to the partial main-chain character of polymer structure, which is acceptable for NLO device applications.

• Bulletin of the Korean Chemical Society
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• v.29 no.4
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• pp.811-816
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• 2008

2,5-Di-(2'-hydroxyethoxy)benzylidenemalononitrile (3) was prepared and polymerized with 2,4-toluenediisocyanate and 3,3'-dimethoxy-4,4'-biphenylenediisocyanate to yield novel T-type polyurethanes 4 and 5 containing 2,5-dioxybenzylidenemalononitrile, nonlinear optical (NLO)-chromophores as part of the polymer backbones. Polyurethanes 4 and 5 were soluble in common organic solvents such as acetone and N,Ndimethylformamide and showed a thermal stability up to $250{^{\circ}C}$ with glass-transition temperatures ($T_g$) in the range $119-146{^{\circ}C}$. The second harmonic generation (SHG) coefficients ($d_{33}$) of poled polymer films at 1064 nm fundamental wavelength were around $5.82{\times}10^{-9}$ esu. The dipole alignment exhibited high thermal stability up to $T_g$, and there was no SHG decay below $140{^{\circ}C}$ due to the partial main-chain character of the polymer structure, which was acceptable for nonlinear optical device applications.

• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1509-1514
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• 2010

Methyl 3,4-di-(2'-hydroxyethoxy)benzylidenecyanoacetate (3) was prepared and condensed with terephthaloyl chloride to yield novel Y-type polyester (4) containing 3,4-dioxybenzylidenecyanoacetate groups as NLO-chromophores, which constituted parts of the polymer main chains. The resulting polymer 4 is soluble in common organic solvents such as acetone and N,N-dimethylformamide. Polymer 4 shows thermal stability up to $280^{\circ}C$ in thermogravimetric analysis with glass-transition temperature obtained from differential scanning calorimetry near $105^{\circ}C$. The second harmonic generation (SHG) coefficient ($d_{33}$) of poled polymer films at the 1064 nm fundamental wavelength is around 2.42 pm/V. The dipole alignment exhibits high thermal stability up to near $T_g$, and there is no SHG decay below $100^{\circ}C$ due to the partial main-chain character of polymer structure, which is acceptable for NLO device applications.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.732-739
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• 2005

The determination of sound pressure radiated from periodic plate structures is fundamental in the estimation of noise level in aircraft fuselages or ship hull structures. As a robust approach to this problem, here a very general and comprehensive analytical model is developed for predicting the sound radiated by a vibrating plate stiffened by periodically spaced orthogonal symmetrical beams subjected to a sinusoidally time varying point load. In this these, we experiment with the numerical analysis using the space harmonic series and the SYSNOISE for measuring the vibration mode and character of response caused by sound radiation with adding the harmonic point force in the thin isotropic plate supported by the rectangular lattice reinforcement. We used the reinforcements, beams of open type section like the style of 'ㄷ' letter; the space of the beams were chosen to be 0.2m, 0.3m, 0.4m. We studied the behavior of sound pressure levels, analysis of vibration mode between support points, connection between frequency function and sound pressure levels, and connection between position function and sound pressure levels.

• Proceedings of the KIEE Conference
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• 2000.11b
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• pp.361-364
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• 2000

In this study, the system which can make the generator's output voltage more stable by using the inverter in terms of PWM method, is designed It is one of the method reducing velocity of the wind in the process of the wind power generation. Thus, in this system, it is necessary to use a excellent current control inverter. So pulse with modulation method with a high-speed switching element is introduced to control the output current. And also, in order to get a fast response when the standard current generated by the vector control algorithm is supplied with the generator, the output control system with the fast response character and the best current control character is suggested. In this way, the result from the introduction of the control system is that a response character to the changable velocity of the wind is excellent, causing the remarkable reduction of the percentage of the harmonic and the outstanding stability of the variation of the output voltage.

• Proceedings of the IEEK Conference
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• 2002.06a
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• pp.383-386
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• 2002

The goal of this study is to realize the PBG lowpass filter using novel PBG structure modification both upper layer and ground layer. It has been designed three aperture slots of ground layer for PBG structure which the center slot shape of ground is two type, rectangular and dumbbell. This PBG LPF llas the character of the broader stopband and smaller size than typical LPF. The measurement results have matched the simulated ones. It has the cutoff frequency of each 4.4650Hz and 3.520Hz and at least -2OdB of the signal suppression at the stopband.

• Bulletin of the Korean Chemical Society
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• v.17 no.1
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• pp.11-15
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• 1996

A series of poly(1,4-phenylene terephthalates) with pendant NLO chromophores was prepared by the solution polycondensation of 2,5-NLO chromophore substituted terephthalic acid with hydroquinone. The polymers obtained gave satisfactory NMR and elemental analysis results when taking into account their expected structures and the inherent viscosity value proved the polymeric character of all polymers. DSC, optical polarizing microscopy and WAXS studies revealed that none of these polymers exhibited liquid crystalline mesophases. Preliminary results on NLO properties of these polymers showed a surprisingly large second harmonic signal relative to a Y-cut quartz plate.