• Journal of the Korean Electrochemical Society
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• v.20 no.1
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• pp.13-17
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• 2017

In this study, we studied the organic electrolyte application to electrochemical capacitor for high operation voltage. For high operating voltage, 5 wt % of gamma butyroloctone (GBL) was added in the bare electrolyte. During the cycle performance, stable SEI layers were formed by reductive decomposition of additive GBL. As a result, columbic efficient of 1M $SBPBF_4$ in EC:DMC(1:1) with GBL composite was enhanced to 70% after the 2000th cycle at voltage range 0-3.5 V. Additionally, SEI layer protected the surface of electrode and prevent the side-reaction between electrolyte to electrode.

• Journal of Korea Society of Industrial Information Systems
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• v.15 no.5
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• pp.179-185
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• 2010

In a sensitivity analysis, an uncertainty importance measure is often used to assess how much uncertainty of an output is attributable to the uncertainty of an input, and thus, to identify those inputs whose uncertainties need to be reduced to effectively reduce the uncertainty of output. A function is called monotonic if the output is either increasing or decreasing with respect to any of the inputs. In this paper, for a monotonic function, we propose a method for evaluating the measure which assesses the expected percentage reduction in the variance of output due to ascertaining the value of input. The proposed method can be applied to the case that the output is expressed as linear and nonlinear monotonic functions of inputs, and that the input follows symmetric and asymmetric distributions. In addition, the proposed method provides a stable uncertainty importance of each input by discretizing the distribution of input to the discrete distribution. However, the proposed method is computationally demanding since it is based on Monte Carlo simulation.

• KDI Journal of Economic Policy
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• v.29 no.2
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• pp.117-133
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• 2007

This paper evaluates the efficiency of monetary policy in Korea within the framework of interest rate feedback rules. For this, a small open macroeconomic model is constructed in a similar fashion to Ball (1999). The model is shown to capture key features of the Korean economy well. Using this estimated model, optimal instrument rules are derived for a set of different monetary policy objectives. Empirical results find that the actual monetary policy in the class of instrument rules was not very effective in stabilizing the output gap relative to inflation. However, seemingly successful inflation stabilization observed in the data are not consistent with the policy rules as the reaction of the interest rate to inflation is very low. It also appears that the central bank did not react right to movements in the real exchange rate. This paper offers some suggestions for the conduct of monetary policy in Korea.

• Korean Journal of Food Science and Technology
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• v.25 no.1
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• pp.39-45
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• 1993

The effects of enzymatic modification with pepsin and actinidin was studied on molecular weight distributions and functional properties of hydrolysates from soy protein isolate (SPI) differing in degree of hydrolysis. The hydrolyzed SPI by pepsin showed 41.5% degree of hydrolysis after 5 min, and maximum hydrolysis was obtained after 2 hours. Actinidin hydrolyzed SPI 26.71% degree after 1 hour. On SDS-PAGE, native SPI showed 9 distinguishable bands on SDS-PAGE gel. Pepsin treated SPI showed one broad band in the lower part of gel. This band was shifted further to the bottom of the gel and became faint as hydrolysis time increased. While actinidin treated SPI showed different SDS-PAGE pattern from pepsin. However PAGE patterns were similar with pepsin and actinidin treated groups. With pepsin treatment, solubility of SPI distinctively increased around isoelectric point(pI). Emulsifying activity (EA) and emulsifying stability (ES) showed marked increase over pH range of $3.0{\sim}8.0$. 5 min modified group had most excellent foam expansion (FE). Foam stability (FS) was increased as pepsin treatment time increased at pI. With actinidin treatment, solubility was increased. 60 min modified SPI had the most effective EA at pH 4.5. However ES was not effected by actinidin treatment. 5 min modified group was most effect in FE. FS was higher at alkaline pH.

• Journal of Wetlands Research
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• v.17 no.4
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• pp.414-420
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• 2015

Nitrogen is one of main causes to induce eutrophication of water system and one of contaminants that must be treated for protection of water system. In this study, it was intended to identify a method to increase operation efficiency of municipal wastewater treatment plant (MWTP) by treating high concentration nitrogen. A laboratory scale reactor was operated by using sludge thickener supernatant in the MWTP. During operation of the laboratory scale reactor, it was intended to induce stable nitritation and analyze effects of related operation factors. As results, it was shown that the nitiritation could be induced artificially through control of retention time and sections where the stable nitiritation was induced were identified also. In particular, highly efficient nitrite conversion efficiency near 90% was identified in condition of 1 day retention time. Especially, it was shown that ammonium nitrogen load affected ammonium nitrogen removal efficiency and nitrite conversion efficiency. In the condition of high ammonium nitrogen load, the nitrite conversion efficiency and the ammonium nitrogen removal efficiency decreased. On the contrary in the condition of low ammonium nitrogen load, it was found that the nitrite conversion efficiency decreased. It means that control of ammonium nitrogen concentration and its retention time is needed for the nitritation. It is considered that for the sewage containing high load nitrogen in sludge treatment process as like the sludge thickener supernatant, the nitritation can be applied, which can be suggested as a modification method of MWTP.

• Applied Chemistry for Engineering
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• v.3 no.1
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• pp.130-137
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• 1992

The Graft copolymerization of acrylonitrile(AN) and styrene(ST) onto chloroprene rubber(CR) were carried out with benzoyl peroxide(BPO) as an initiator. The synthesized graft copolymer(ACS) was separated from polymeric mixture by the extraction with ethyl acetate and n-hexane, acetone and methanol, dimethylformamide(DMF) and methanol mixed solvent systems. The graft copolymer obtained, acrylonitrile-chloroprene-styrene(ACS) was identified by IR spectrophotometer. The effect of mole ratio of styrene to acrylonitrile, reaction time and temperature, initiator concentration, CR content and solvents on graft copolymerization were examined. It was observed that the grafting efficiency increased with [ST]/[AN] mole ratio and reaction time. The grafting efficiency increased with increasing initiator concentration and CR content. The maximum grafting efficiency was obtained when the mole ratio of [ST]/[AN] was 1.5 and reaction was made at 40hrs, and $70^{\circ}C$ using chloroform/toluene mixed solvent. The thermal properties, light resistance and flammability of ACS were compared with those of ABS and AES. It was found that flame retardancy of related polymers increased in the order ACS>ABS>AES. The thermal stability of ACS was greatly improved when compared with ABS or AES. Morphology of ACS was also investigated by using a transmisson electron microscope(TEM).

• Journal of Aerospace System Engineering
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• v.15 no.5
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• pp.8-15
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• 2021

This paper describes a design method using an optimization technique to satisfy the longitudinal handling quality of high maneuverable jet aircraft. The dynamic inversion technique was applied to the target aircraft, and the control gain optimization satisfied the longitudinal short-period handling quality, however, the stability margin was not considered. If the stability margin is not satisfied, it is necessary to directly readjust the gains through trial and error methods for improvement. To improve this, an additional compensator and an optimization constraint were added to the control gain optimization procedure. In addition, the degree of handling quality satisfaction with the optimization result was reevaluated, and additional control evaluation criteria for the convergence of the time response and the steady state error that the flight performance requirement set as the optimization constraint cannot be reflected, and the results are described.

• Journal of Korea Port Economic Association
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• v.26 no.4
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• pp.88-100
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• 2010

This paper investigates the influence of industrial activity volatility and exchange rate volatility on import container volume of the Korea during the 1999:1- 2010:9. Conditional variance from the GARCH(1, 1) model is applied as the volatility. The Johansen multivariate cointegration method and the error correction (general-to-specific) method are applied to study the relationship between import volume and its determinants. The empirical results show that volatility has statistically significant negative effect on import volume.

• Applied Chemistry for Engineering
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• v.16 no.2
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• pp.282-287
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• 2005

Palladium membranes, which are permselective to hydrogen separation, were used for the hydrogen purification and in membrane reactors for improving conversions by shifting the reaction equilibrium. Palladium/ceramic composite membranes were prepared by electroless plating technique and then etched in titanium chloride ($TiCl_4$) as a post treatment to enhance the membrane's durability. These membranes were used for membrane reactors in water gas shift (WGS) reaction. CO conversions for the membrane reactor were obtained according to experimental parameters and compared to the traditional reactor without a palladium/ceramic membrane. As a result, CO conversion using palladium membrane reactor at an appropriate condition was over 20~25% greater than that without the membrane reactor. The stability in the long-term test of up to 120 h for WGS reaction with the membrane reactor was good without the degredation of CO conversion.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2001.05a
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• pp.313-319
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• 2001

본 연구는 시뮬레이터 실험에서 필수적으로 발생하는 Simulator Sickness(SS)를 평가하기 위하여 동적 시뮬레이터에서 일정한 속도(60km/h)로 1시간 주행했을 때 Simulator Sickness Questionnaire(SSQ)를 이용하여 주관적 Sickness를 평가하고 생리적 반응으로 심박 변동량(HRV)과 피부온도 및 피부저항을 측정하여 성별, Simulator 수준에 따라 비교 분석하였다. 분석 결과 동적 시뮬레이터에서 주행시 주관적인 Simulator Sickness는 안정에 비해 시간이 지남에 따라 45분까지 선형적으로 증가하여UT고, 여자와 sick군이 남자와 nonsick군에 비해 더 높았으며 sickness 수준간에서는 유의성이 나타났지만 남녀간의 유의한 차이는 없었다. 생리적 반응은 시간에 따른 변화는 없었으나 안정에 비해 R-R 간격의 감소, (LF+MF)/total 및 (LF+MF)/HF의 증가로부터 교감 신경이 활성화되었으며 피부온도의 감소와 피부저항의 증가로부터 긴장도가 커짐을 알 수 있었다. 주행 50분 이후는 HF/total가 감소하여 부교감 신경의 작용이 저하되는 것으로 나타났다.. 성별, sickness수준에 따라서는 남녀간에는 부분적으로 유의한 차이가 있었고 평균 R-R 간격에서만 sick군이 nonsick군보다 유의하게 낮았다.