• 국제지역연구
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• 제13권2호
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• pp.277-297
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• 2009

이 논문은 외환위기 이후 1998년 1월 ~ 2008년 7월 까지의 한 일 주가와 KRW/JPY 실질 환율간의 장 단기 균형관계를 분석하였다. 실증분석은 월별자료를 사용하여 계절조정에서 오는 편의(bias)를 극복하기 위하여 자료를 계절조정하지 않고 계절성을 모형에 반영하여 단위근 검정과 VEC모델을 분석하였다. 실증분석결과 한일 주가와 환율간 장기균형관계에 대한 강한 증거를 발견하였다. 이는 한 일 양국간 어느 한 국가에 대한 시장예측은 다른 국가 시장에 대한 예측이 가능하다는 것으로 효율시장가설이 위배됨을 의미한다. 한국의 주가와 KRW/JPY 실질 환율 간 장기 음(-)의 부호를 나타내 국내통화의 절하는 국내기업을 더 경쟁적으로 만들어 수출의 증가를 이끌기 때문에 주가를 상승시키며, 주가와 환율간 음(negative)의 상관관계를 의미한다는 전통적 가설을 지지하는 것으로 나타났다.

• 한국항만경제학회지
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• 제23권1호
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• pp.1-18
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• 2007

본 연구에서는 환율의 컨테이너 물동량에 대한 영향의 비중을 고려하여 외환위기 이후 환율변동성이 커짐에 따라 컨테이너 물동량도 상당히 영향을 받은 것으로 예상되기 때문에 환율변동성의 컨테이너 물동량에 대한 장 단기적 영향을 체계적으로 분석하고 시사점을 도출하고자 한다. 환율변동성을 도출하기 위하여 GARCH 모형을 이용하여 우리나라의 환율 변동성 모형을 분석한다. 물론 구축된 모형을 분석하기 이전에 설정된 변수들과 모형의 안정성 검정을 위하여 단위근 검정과 공적분 검정을 실시한다. 또한 환율의 변동성이 컨테이너 물동량에 미치는 동태적 영향을 보기 위해 오차수정모형과 충격반응 및 분산분해를 실시하고 마지막으로 결론과 시사점을 도출한다. 분석결과 환율변동성을 포함시킨 컨테이너물동량함수를 회귀 분석한 결과 추정계수가 모두 이론적 예상과 부호가 일치하고 통계적 유의성도 높은 것으로 나타났다. 환율변동성은 우리나라의 컨테이너 물동량에 부(-)의 영향을 미치는 것으로 나타났다. 환율변동에 의한 불확실성이 예상됨으로써 위험기피에 의하여 무역과 생산이 감소하고 이에 따라 컨테이너 물동량도 영향을 받은 것으로 판단된다. 오차수정모형에 근거한 인과관계 검정에서 단기와 장기 모두 환율변동성에서 컨테이너 물동량간의 일방적 인과관계가 존재하였다. 또한 충격반응함수에서 나타난 바와 같이 환율변동성 충격에 대하여 컨테이너 물동량은 부(-)의 영향을 받으며 그러한 부의 효과는 비교적 짧은 기간 내에 안정적인 추세로 수렴된다. 예측오차의 분산분해의 결과는 환율변동성과 실질환율이 컨테이너 물동량의 분산에 상당한 영향을 미치고 있음을 알 수 있다.

• 수산경영론집
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• 제46권1호
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• pp.75-91
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• 2015

With the increasing improvement of living standard, people pay more attention to the quality and security of their food. There is an increase in the consumption of aquatic products and a vast prospect of its trade. Fisheries as a major one of the traditional industries in China have significant price advantages and natural resources. However, marine pollution in China is more and more serious and the expecting of aquatic products has been seriously influenced by green barriers in the recent years. This paper tries to examine the effect of Chinese marine pollution on export of aquatic products in China. This paper utilizes cointegration test to estimate long-run equilibrium between marine pollution and fisheries products export. The results indicate that real exchange rate and income variable have positive effects and fish price has negative effect on China's fisheries export to Korea. However, marine pollution variable has no statistically significant effect on dependant variable. And according to the result of China's fisheries export to Japan, exchange rate has positive effect and both fish price and marine pollution variable have negative effects on export. Lastly, marine pollution and income level have effects on dependant variable in the case of Hong Kong, but exchange rate and price variable have no significant effect on aquatic products export from China to Hong Kong. In a word, marine pollution of China is a serious problem and it has negative effect on Chinese export of aquatic products.

• Computers and Concrete
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• 제32권3호
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• pp.287-302
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• 2023

Corrosion of reinforcing bars in reinforced concrete structures due to chloride attack in environments containing chloride ions is one of the most important factors in the destruction of concrete structures. According to the abundant reports that the corrosion rate around the repair area has increased due to the macro-cell current known as the incipient anode, it is necessary to understand the effective parameters. The main objective of this paper is to investigate the effect of the kinetic parameters of corrosion including the cathodic Tafel slope, exchange current density, and equilibrium potential in repair materials on the total corrosion rate and maximum corrosion rate in the patch repair system. With the numerical simulation of the patch repair system and concerning the effect of parameters such as electromotive force (substrate concrete activity level), length of repair area, and resistivity of substrate and repair concrete, and with constant other parameters, the sensitivity of the macro-cell current caused by changes in the kinetic parameters of corrosion of the repairing materials has been investigated. The results show that the maximum effect on the macro-cell current values occurred with the change of cathodic Tafel slope, and the effect change of exchange current density and the equilibrium potential is almost the same. In the low repair extant and low resistivity of the repairing materials, with the increase in the electromotive force (degree of substrate concrete activity) of the patch repair system, the sensitivity of the total corrosion current reduces with the reduction in the cathode Tafel slope. The overall corrosion current will be very sensitive to changes in the kinetic parameters of corrosion. The change in the cathodic Tafel slope from 0.16 to 0.12 V/dec and in 300 mV the electromotive force will translate into an increase of 200% of the total corrosion current. While the percentage of this change in currency density and equilibrium potential is 53 and 43 percent, respectively. Moreover, by increasing the electro-motive force, the sensitivity of the total corrosion current decreases or becomes constant. The maximum corrosion does not change significantly based on the modification of the corrosion kinetic parameters and the modification will not affect the maximum corrosion in the repair system. Given that the macro-cell current in addition to the repair geometry is influenced by the sections of reactions of cathodic, anodic, and ohmic drop in repair and base concrete materials, in different parameters depending on the dominance of each section, the sensitivity of the total current and maximum corrosion in each scenario will be different.

• The Journal of Asian Finance, Economics and Business
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• 제5권3호
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• pp.7-17
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• 2018

This paper examines short-run and long-run dynamic relationships between selected macroeconomic variables and stock prices in the Korea Stock Exchange. The data is restricted to the period for which monthly data are available from January 1986 to October 2016 (370 observations) retrieved from the Economic Statistics System database sponsored by the Bank of Korea. The study employs unit root test, cointegration test, vector error correction estimates, impulse response test, and structural break test. The results of the Johansen cointegration test indicate at least three cointegrating equations exist at the 0.05 level in the model, confirming that there is a long-run equilibrium relationship between stock prices and macroeconomic variables in Korea. The results of vector error correction model (VECM) estimates indicate that money supply and short-term interest rate are not related to stock prices in the short-run. However, exchange rate is positively related to stock prices while the industrial production index and inflation are negatively related to stock prices in the short-run. Furthermore, the VECM estimates indicate that the external shock, such as regional and global financial crisis shocks, neither affects changes in the endogenous variables nor causes instability in the cointegrating vector. This study finds that the endogenous variables are determined by their own dynamics in the model.

• 공업화학
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• 제28권5호
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• pp.539-546
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• 2017

본 연구는 산성유해가스 제거를 위한 고효율 음이온교환 복합 폼 화학필터를 제조하기 위하여 폴리우레탄(PU) foam에 다른 종류의 PSA를 사용하여 상용이온교환수지를 부착하여 제조, 이의 내수성, 내화학성, 접착신율, 농도와 유속에 따른 HCl과 HF의 흡착특성에 관하여 연구하였다. 그 결과 접착신율은 ATE-701은 900%, AT-4000C는 1,500%, HCA-1000는 2,400%이며, 내수성 및 내화학성평가에서 HCA-1000의 탈리율이 6% 미만으로 우수한 내구성을 가짐을 확인하였다. HCl, HF의 농도와 유속이 증가함에 따라 흡착이 빠르게 일어났으며 유속과 농도에 관계없이 110 min 이후 100% 흡착파과평형이 일어남을 확인할 수 있었다. 또한 SEM Morphology 관찰 결과 점착제가 고르게 분산되어 있고 이온교환수지의 다공구조가 유지되었으며, 흡-탈착 공정에서 성능저하가 없는 것으로 보아 내구성이 있음을 확인하였다.

• Journal of Biosystems Engineering
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• 제23권1호
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• pp.21-30
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• 1998

A theoretical model was developed to evaluate the effects of soil and airflow characteristics on the soil-air heat exchanger performances. The model, which includes three-dimensional transient energy and mass equilibrium-equation, was solved by using a computer program that uses Finite Difference Methods and Gauss-Seidel iteration computation. Energy gains, heat exchange efficiencies, and outlet air temperature are presented including the effects of soil moisture content, soil conductivity, soil thermal diffusivity, and soil initial temperature. Also, data related to the effects of airflow rate and inlet air temperature on the thermal performance of the system are presented. The results indicated that energy gains depend on soil conductivity, soil thermal diffusivity, and soil initial temperature. Heat exchange efficiencies relied on air mass flow rate and soil moisture content.

• Smart Structures and Systems
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• 제33권3호
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• pp.243-251
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• 2024

Modeling of vibrations of a rotating pendulum with working shape memory alloy rod has been performed in the frames of a microstructural model taking into account the latent heat release, absorption and the heat exchange during direct and reverse martensitic transformation. It has been shown that the influence of the latent heat, the rate of preliminary deviation of the pendulum from the equilibrium, the rate of heating and cooling can have a significant impact on the vibrations and damping characteristics of the system.

• 폴리머
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• 제26권5호
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• pp.551-558
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• 2002

술폰산형 섬유이온교환체를 이용하여 도금 폐수 중 니켈 이온 분리를 위해 각각의 조건에 따른 니켈 이온에 대한 흡착 특성을 관찰하였다. 술폰산형 섬유이온교환체의 함수율은 술폰화도 극성이 클수록 크게 나타났으며 이온교환용량은 술폰화도가 증가함에 따라 증가하였으며 술폰화도 16%에서 3.38 meq/g로 높게 나타났다. 니켈이온의 흡착은 pH 변화에 따라 크게 변화하지 않았고 모든 흡착은 10분 이내에 약 7.5 mg/min의 흡착속도로 매우 빠르게 평형에 도달하였다. 재생 시 흡착용량은 7회까지 3.15 meq/g으로 거의 100% 가까이 탈착되었으며 그 이상에서는 2.01 meq/g으로 약간 감소하는 것으로 보아 본 연구에 사용한 이온교환체는 내구성에 문제가 없는 것으로 판단되었다. 한편 흡착평형 시간은 L/D의 값이 증가함에 따라 선형적으로 증가하였으며, 최대 흡착용량은 각각 2.71∼3.01 meq/g으로 약간 증가하였고 L/D의 변화에 크게 영향이 없는 것으로 보아 L/D<2로 흡착칼럼의 설계가 가능할 것으로 사료되었다. 또한 이온교환 섬유의 충전비가 일정할 때 pH 변화에 따른 니켈 이온의 흡착량은 산성 pH에서는 큰 변화가 없는 것으로 보아 도금수세액의 pH가 산성인 점을 고려할 때 pH 5 이하가 적합한 것으로 판단되었다.

• Nuclear Engineering and Technology
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• 제33권1호
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• pp.83-92
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• 2001

The properties of off-gas generated from vitrification process of ion-exchange resin were characterized. Theoretical composition and flow rate of the off-gas were calculated based on chemical composition of resin and it＇s burning condition inside CCM. The calculated off-gas flow rate was 67.9Nm$^3$/h at the burning rate of 40kg/h. And the composition of off-gas was avaluated as $CO_2$(41.4%), steam(40.0%), $O_2$(13.3%), NO(3.6%), and SO$_2$(1.6%) in order. Then, actual flow rate and composition of off-gas were measured during pilot-scale demonstration tests and the results were compared with theoretical values. The actual flow rate of off-gas was about 1.6 times higher than theoretical one. The difference between theoretical and actual flow rates was caused by the in-leakage of air to the system, and the in-leakage rate was evaluated as 36.3Nm$^3$/h. Because of continuous change in the combustion parameters inside CCM, during demonstration tests, the concentration of toxic gases showed wide fluctuation. However, the concentration of CO, a barometer of incompleteness of combustion inside CCM, was stabilized soon. The result showed quasi-equilibrium state was achieved two hours after feeding of resin.