• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.5
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• pp.399-406
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• 2016

The large scale wind turbine blades usually experience periodic change of inflow speed due to blade rotation inside the ground shear flow region. Because of the vertical wind shear, the inflow velocity in the boundary layer region is maximum at uppermost position and minimum at lowermost position. These spatial distribution of wind speeds can lead to the periodic oscillation of the 6-component loads at hub and low speed shaft of the wind turbine rotor. In this study we compare the aerodynamic loads between two inflow conditions, i.e, uniform flow (no vertical wind shear effect) and normal wind profile. From the computed results all of the relative errors for oscillating amplitudes increased due to the ground shear flow effect. Especially bending moment and thrust at hub, and bending moments at LSS increased enormously. It turns out that the aerodynamic analysis including the ground shear flow effect must be considered for fatigue analysis.

• Applied Biological Chemistry
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• v.42 no.2
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• pp.152-155
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• 1999

Effects of pH, amino acids, hydrolyzed protein and potassium phosphate on caramelization were investigated for improvement of its reaction rate. The caramelization was performed with starch syrup at $110^{\circ}C$ and the different color functions-metric saturation(Suv), 5-hydroxymethylfurfural (HMF) contents and absorbance at 420 nm were measured. As the pH was raised from 4 to 10, the reaction rate (Suv/hr) was increased by 31.9% along with significant increase in HMF content and absorbances at 420 nm. Among the several amino acids, arginine and glycine were very effective for improvement of caramelization, which may be due to Maillard reaction. When $K_2HPO_4$ were added in different ratio with arginine, glycine, HVP or HAP, the effects of arginine and HAP on thee rate were markedly enhanced while the effects of glycine and HVP were rather reduced.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5D
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• pp.723-730
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• 2006

Recently, The flexible moving block system in train operation has been introduced to the worldwide rail transportation markets. This paper is a comparative study of the conventional fixed block systems effects and the flexible moving block system on train operating time saving. Based on the literature review, the new algorithm is developed. It is to calculate the optimum headway time of the train. The proposed algorithm can overcome some of the existing algorithm problems, such as the limits of the data and unaware of the rail characteristic. The total travel time saving effect has been analyzed by applying the skip stop scheduling system to the each block system. The results of this study indicated that the total travel time is approximately 40% decreased and the schedule velocity is approximately 24% improved when the moving block system is applied. The results of this study could be used as a theoretical basis for the selection of rail signal system in Seoul's subway number 2 line.

• Journal of Convergence for Information Technology
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• v.10 no.9
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• pp.15-21
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• 2020

This paper presents the outlier detection algorithm in the estimation method of a source location and velocity based on two-step weighted least-squares method using time difference of arrival(TDOA) and frequency difference of arrival(FDOA) data. Since the accuracy of the estimated location and velocity of a moving source can be reduced by the outliers of TDOA and FDOA data, it is important to detect and remove the outliers. In this paper, the method to find the minimum inlier data and the method to determine whether TDOA and FDOA data are included in inliers or outliers are presented. The results of numerical simulations show that the accuracy of the estimated location and velocity is improved by removing the outliers of TDOA and FDOA data.

• Journal of Labour Economics
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• v.37 no.4
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• pp.25-57
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• 2014

Analysing the effects of expanded trade liberalization on the domestic labor market such as the flexibility of employment adjustment and the wage elasticity of employment etc. with industry base data, we get some important results as follows. The speed of employment adjustment in whole industries is turned out to be more rapid on the employee basis than on the whole worker basis. And the speed of employment adjustment is more rapid in the industries with high level of import ratio than those with high level of export ratio. In sum, viewing on the employee basis, the expanded trade liberalization makes the speed of employment adjustment slower slightly in individual industry level, and it is led mainly by the effects of export ratio rising. In case of the wage elasticity of employment, it becomes to be much higher as rates of openness or export ratios go higher, so the environment of jobless growth seems to be much more strengthened in this country.

• Korean journal of food and cookery science
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• v.10 no.2
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• pp.121-125
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• 1994

The antioxidant activity of gingerol according to temperature on soybean oil were examined by measuring peroxide value(POV). The induction period(IP) of soybean oil was 45; 276.0, 65; 17.0 and 105$^{\circ}C$ : 4.7 hours respectively by-measuring POV. The relative antioxidant effectiveness(RAE) of ginge-rol group were 45; 191, 65; 200, 65: 150, 85: 132 and 105$^{\circ}C$;106%. 'The activation energies(Ea) and temperature coefficients(Q10) for Arrhenius equations at 45∼105$^{\circ}C$, was estimated in order to find out the influence of temperature on the oxidation of soybean oil contai-ning various antioxidants. The soybean oil was more unstable at 45∼65$^{\circ}C$ than at 65∼105$^{\circ}C$ in the Ea and Q10. The soybean oils containing gingerol were more stable than the control group at 45∼105$^{\circ}C$, however, BHT group was unstable compared to gingerol group at 85∼105$^{\circ}C$.

• Journal of the Korean Chemical Society
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• v.22 no.1
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• pp.30-36
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• 1978

The kinetics of hydrolysis of ${\alpha}$-nitrobenzaldehydephenylhydrazone derivatives (p-$NO_2$, m-$NO_2$, p-Cl, p-$CH_3$) have been investigated by UV spectrometry in 25% dioxane-water at $25^{\circ}C$ and a rate equation which can be applied over wide pH range was obtained. From the rate equation and the effect of solvent, substituent and pKa on the rate equation, the following reaction mechanisms were proposed. Below pH 3.0 the hydrolysis of ${\alpha}$-nitrobenzaldehydephenylhydrazone proceeds by $S_N1$ mechanism, while above pH 4.0 the hydrolysis proceeds through 1,3-dipole ion mechanism. In the range of pH from 3.0 to 4.0 these two reactions occur competitively.

• Composites Research
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• v.12 no.5
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• pp.40-53
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• 1999

The interlaminar facture behavior of multidirectional carbon-fiber/epoxy composite laminates under low and high rates of test, up to rate of about 11.4m/s has been investigated using the double cantilever beam specimens. The mode I loasing with rates above 1.0m/s had considerable dynamic effects on the load-time curves and thus revealed higher values of the average crack velocity than thet expected from a simple proportional relationship with the test rate. The modified beam analysis utilizing only the opening displacement and crack length exhibited an effective means for evaluating the dynamic fracture energy $G_{IC}$. Flexural modulus increased gradually with an increase of the test rate, which was utilized in the evaluation of $G_{IC}$. Values of $G_{IC}$ at the crack initiation and arrest were scarcely changed with increasing test rate up to 1.0m/s. However the maximum $G_{IC}$ was much enlarged at 11.4m/s due to the large amount of fiber bridging the crack tip. The larger the initial crack length, the smaller the maximum $G_{IC}$ at high rate.

• Journal of Conservation Science
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• v.25 no.1
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• pp.87-100
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• 2009

We carried out the effect verification of conservation treatment focusing on basement rock of alkali granite at the Yukjonbul (two-pairs of Buddha Triads) carved on rock cliff of Samneung valley in Namsan mountain of Gyeongju. The conservation treatments were used to ethylsilicate-type rock consolidant and epoxy-type resin. It is treatment method that the epoxy-type resin have been applied one time into the exfoliation area, after rock consolidation treatment have been worked for three times. As the result of measuring ultrasonic velocity, P-wave velocity of the exfoliation area was relatively increased after applied the conservation treatments. The ultrasonic velocity of all area was increased as 27.8%. This result has been proved with consolidation effects by consolidant and filler for stone cultural heritages. The treatment method should be worked about three time to consolidate sufficiently for rocks.

• Journal of the Korean Chemical Society
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• v.37 no.8
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• pp.695-701
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• 1993

Rate constants of solvolysis of 2-thiophenesulfonyl chloride were determined in aqueous binary mixtures with methanol, ethanol, acetone in water and in methanol. These data are interpreted using the equation of Grunwald-Winstein and Kivinen relationship. Also, kinetic solvent isotope effects in water and in methanol and product selectivities in alcohol-water mixtures were determined. Kinetic solvent isotope effect for hydrolysis of 2-thiopenesulfonyl chloride was 2.24 and 1.47 for methanol and water, respectively. Selectivity values for formation of ester relative to acid in ethanol-water mixtures show maximum S value. From kinetic solvent isotope effect in methanol and water, selectivity data in aqueous alcoholic solvents and solvent effects, it is proposed that the reaction channel favoured in low polarity solvents is general-base catalysis and/or is possibly addition elimination (S$_A$N) reaction pathway and in high polarity solvents iS S$_N$2 reaction mechanism.