• International Area Studies Review
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• v.20 no.1
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• pp.147-165
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• 2016

We empirically examine the validity of second generation endogenous growth theory suing 21 OECD countries' panel data(1981~2011). Due to non-stationarity in all variables, we test the cointegrated relationships strongly supporting the semi-endogenous growth model. In the estimation of total factor productivity growth function, the growth of domestic and foreign R&D investment levels statistically significantly affect total factor productivity growth. R&D intensity, however, has significant impacts on the total factor productivity growth only in a few models, and international technology gap also has positive impacts on GDP growth. Thus the semi-endogenous growth model is relatively supported while fully endogenous growth model is weakly and occasionally supported in OECD countries. The policy implication of supporting the semi-endogenous growth model is that the sustaining growth requires increasing R&D expenditures.

• The Journal of Engineering Geology
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• v.34 no.1
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• pp.25-38
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• 2024

Laboratory tests of accelerated artificial weathering compared the effects of seawater and acidified distilled water on rock weathering. The experiments simulated chemical and physical weathering of five different types of volcanic rock by applying 45 freeze-thaw cycles using seawater and acidified distilled water (pH 3), both at 70℃. The physical properties and uniaxial compressive strength (UCS) of the rocks were measured after 15 and 45 cycles of artificial weathering. Most of degradation of physical properties appeared within the first 15 cycles, and acidified distilled water had a greater effect than seawater. Analysis of variance (ANOVA) statistically evaluated the differences in UCS of the different rock types during the tests. The rate of UCS reduction after 45 cycles was similar across the samples, being independent of the rock type and the trend of changes in physical properties. In contrast to the changes in the physical properties, the UCS was more affected by seawater than by acidified distilled water.

• Economic and Environmental Geology
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• v.46 no.5
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• pp.411-424
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• 2013

Assessment and damage reduction strategy of acidic rock drainage were conducted in a section of ${\bigcirc}{\bigcirc}$ highway construction site. The geology of the studied section consists of Icheonri sandstone and intermediate to acidic volcanic rocks. Sulfides occur as a disseminated type in sandstone and volcanics which were altered by the hydrothermal solution of granite intrusion. Volcanics and sandstone with a high content of sulfide were classified as a potentially acid rock drainage(ARD) forming rock. The drainage originated from those rocks may acidify and contaminate the surrounding area during the highway construction. Therefore, the drainage should be treated before it is discharged. A slope landslide hazard due to the ARD was also expected and the coating technology was recommended for the reduction of ARD generation as a preemptive measure before reinforcement work for enhancing slope stability such as shotcrete and anchor. According to the ARD risk analysis, those rocks should not be used as cement aggregate, but only to be used as a bank fill material of a filling-up system that allows minimal contact with rainfall and groundwater.

• Journal of Technology Innovation
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• v.28 no.2
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• pp.63-100
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• 2020

This study analyzes the effectiveness of government supported R&D program for SMEs by measuring TFP improvements. We estimate TFP for Korean companies from 2011 to 2018 using Levinsohn and Petrin (2003) method which reduces endogenous problem. Then government R&D beneficiary companies were extracted from the NTIS and linked to TFP estimates. The empirical results are as follows. First, as a result of estimating production function, the contribution of TFP to value-added is more important than in the past. Second, the TFP gap between large firms and SMEs continues to wide and there is no sign of easing.(from 3.72 times in 2011 to 5.23 times in 2018). Third, SMEs beneficiaries show higher TFP level than non-beneficiaries. However their TFP was on the decline until government support. After government supported R&D program, it reverses upward. Fourth, although one-year TFP improvement of beneficiaries is bigger than non-beneficiaries, it is smaller than the control group through PSME. Because SMEs participating in government R&D programs had showed downward trend of TFP until R&D program, it is necessary to examine whether there is a fundamental discordance between the demand of SMEs for R&D program and governments policy goal. More sophisticated program design will be required to escape the recognition that government R&D programs for SMEs are just charity.

• Journal of Environmental Science International
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• v.5 no.5
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• pp.663-676
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• 1996

The analyzed results of observed precipitation and its pH in Kwangiu for 262 days from fan. 1, 1991 to Dec. 31, 1995 are as follows. The annual mean pH was 5.7, and the monthly mean pH values of January-May and November were less than 5.6 in Kwangiu. The ratio of acid rain for these periods was about 48.1%, almost half that of the total observed days. In March, the pH was 5.4 and the ratio of acid precipitation was 69%, an especially serious situation. In the spring, the pH value was 5.5, thus weakly acidic. The pH of precipitation tended to decrease with greater precipitation. The relation between persistent time and pH of precipitation is variable, but if the persistent time is long, the pH is constant and low. It is fortunate that there is an increasing trend of pH in interannual variation, but it is thought important that the amplitude of variation of pH in 1995 was high and the pH value was 4.1 in October and November. Because heavy and persistent precipitation effects the accumulation of acidity, more concern about acid rain is needed.

• KDI Journal of Economic Policy
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• v.25 no.2
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• pp.3-53
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• 2003

Using the plant level panel data on Korean manufacturing during 1990-98 period, this study tries to assess the role of entry and exit in enhancing aggregate productivity, both qualitatively and quantitatively. Main findings of this study are summarized as follows. First, plant entry and exit rates in Korean manufacturing seem quite high: they are higher than in the U.S. or several developing countries for which comparable studies exist. Second, in line with existing studies on other countries, plant turnovers reflect underlying productivity differential in Korean manufacturing, with the "shadow of death" effect as well as selection and learning effects all present. Third, plant entry and exit account for as much as 45 and 65 percent in manufacturing productivity growth during cyclical upturn and downturn, respectively. The findings of this study show that the entry and exit of plants has been an important source of productivity growth in Korean manufacturing. Plant birth and death are mainly a process of resource reallocation from plants with relatively low and declining productivity to a group of heterogeneous plants, some of which have the potential to become highly efficient in future. The most obvious lesson from this study is that it is important to establish policy or institutional environment where efficient businesses can succeed and inefficient businesses fail.

• Journal of Life Science
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• v.14 no.5
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• pp.809-814
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• 2004

To investigate the effect of the electrolyzed acidic water for soybean sprouts growth, the responses of characteristics of soybean sprouts were evaluated. Soybean sprouts grown by the electrolyzed acidic water showed shorter length in total body, root, and hypocotyl, etc. but they were evaluated to be increased in hypocotyl diameter and weight per sprout. Total length of soybean sprouts grown for 5 days by electrolyzed acidic water were much shorter than those by tap water. Soybean sprouts grown by tap water showed rapid growth in length even after 5 days but no more growth in length for those grown by electrolyzed acidic water. The growth of hypocotyl showed the same tendency as total length. No difference in root length among the soybean sprouts grown for 4 ~ 11 days by electrolyzed acidic water while those grown by tap water showed continuous rapid growth in length. The diameter of hypocotyl was thicker in those grown by electrolyzed acidic water than those grown by tap water and increased up 5 days. The weight of cotyledon grown by electrolyzed acidic water showed the proportional increase to the growing days but those grown by tap water showed no increase in hypocotyl weight up to 7 days, but a little bit increase after 11 days with the growth of new buds. The fresh weight per sprout was higher in those grown by electrolyzed acidic water until 7 days than tap water but it was the same weight in 11 days cultivation. The electrolyzed acidic water effected on shortening of hypocotyl and root length, thickening of hypocotyl diameter, and enlarging of cotyledon during soybean sprout cultivation.

• Korean Journal of Food Science and Technology
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• v.28 no.4
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• pp.779-785
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• 1996

Sansung takju, the Korean traditional liquor at a local area of Sansung in Pusan, has been widely drunken due to its tradition in this area. The studies on microorganisms of kokja, fermentation process and shelf-life of takju were carried out. The most abundant microorganism identified from a commercial Sansung kokja was Aspergillus, Mucor, Rhizopus and Penicillium were also identified. In case of a home-made Sansung kokja, Mucor was the most abundant one. Aspergillus, Rhizopus and Absidia were also identified in it. Saccharomyces, Micrococcus and Bacillus were identified in both kokja's but acid production bacteria were not found. Ethanol fermentation was carried out at $25^{\circ}C$ and $30^{\circ}C$ using each kokja. The rate of ethanol production was faster at $30^{\circ}C$ than at $25^{\circ}C$, while higher viable yeast count and final ethanol content were obtained at $25^{\circ}C$ than at $30^{\circ}C$. The ethanol contents of the mashes using a commercial Sansung kokja and a home-made Sansung kokja after 14 days at $25^{\circ}C$ were 11.0% and 12.4%, respectively. The shelf-life of takju was affected more by ethanol content in the product than by storage temperature. The product stored at $-15^{\circ}C$ did not change significantly in acidity but tasted watery due to thawing. In case of Sansung takju containing 6%ethanol, level of acidity increased and pellicle was formed on the surface of the product during storage at $30^{\circ}C$. In case of Sansung takju containing 9% or 12% ethanol, no significant changes in acidity and appearance were observed for 14 days at $30^{\circ}C$.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.6
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• pp.904-909
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• 2012

Acid sulfate soil (ASS) and potential acid sulfate soil (PASS) are distribution in worldwide and originate from sedimentary process, volcanic activity, or metamorphism and are problematic in agriculture and environmental due to their present and potential acidity developed by the oxidation. The PASS was defined as soil materials that had sulfidic layer more than 20 cm thick within 4 m of the soil profile and contained more than 0.15% of total-sulfur (T-S). A tentative interpretative soil classification system was proposed weak potential acid sulfate (T-S, 0.15-0.5%), moderate potential acid sulfate (T-S, 0.5-0.75%) and strong potential acid sulfate (T-S, more than 0.75%). PASS due to excess of pyrite over soil neutralizing capacity are formed. It provides no information on the kinetic rates of acid generation or neutralization; therefore, the test procedures used in acid base account (ABA) are referred to as static procedures. The net acid generation (NAG) test is a direct method to measure the ability of the sample to produce acid through sulfide oxidation and also provides and indication. The NAG test can evaluated easily whether the soils is PASS. The samples are mixed sandy loam and the PAS from the hydrothermal altered andesite (1:3, 1:8, 1:16, 1:20, 1:40, 1:80 and 1:200 ratios) in this study. We could find out that the NAG pH of the soil containing 0.75% of T-S was 2.5, and that of the soil has 0.15% of T-S was 3.8. NAG pH test can be proposed as soil classification criteria for the potential acid sulfate soils. The strong type has NAG pH of 2.5, the moderate one has NAG pH of 3.0, and the weak one has NAG pH of 3.5.

• Journal of Korean Society of Forest Science
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• v.84 no.1
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• pp.103-113
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• 1995

To estimate buffer capacity and sensitivity of forest ecosystem to acid rain in Taejon, ionic components of throughfall, stemflow, soil leachate, and open rain in Pinus rigida and Quercus variabilis forest were analysed. The spatial sensitivity based on parent rock and forest type was given by IDRISI of GIS which created imagery conversion from soil and vegetation map. Parent rocks and soils were classified into acidic, sedimentary, metamorphic rock and then subdivided based on $SiO_2$ content. Average pH of vegetation leachate was higher in throughfall but lower in stemflow than open rain and higher in Quercus variabilis forest than in Pinus rigida forest. The flow of $SO{_4}^{2-}$, $NO_3{^-}$ and $Cl^-$ through vegetation leaching(throughfall plus stemflow) into soil were 7.2, 4.3, and 2.5 times, respectively, higher in Pinus rigida forest and 4.4, 2, and 2.5 times, respectively, higher in Quercus variabilis forest than in open field. But the concentration of exchangeable cations was 4.1 times higher in Pinus rigida forest and 4.6 times higher in Quercus variabilis forest than in open field. Average pH of soil leachate was lower than that of throughfall, but higher than that of stemflow. The concentration of exchangeable canons and $Al^{3+}$ in soil leachate were more in Pinus rigida forest than in Quercus variabilis forest and increase signficantly with the increase of acidic deposits. Pinus forest had more deposition and canopy interception of acidic pollutants and more nutrient loss than Quercus forest, and Quercus forest had more cation exchange and proton consumption and than consequently had less nutrient loss and better buffer capacity than Pinus forest. The 69% of forest soils was distributed on acidic rock, 25% of it on metamorphic rock, and 6% of it on intermediate and basic rock. Acidic rock residuals which had low very canon exchange capacity and high sensitivity to acid rain occupied a half of total forest land in Taejon area. Therefore forests in Taejon showed high vulnerability to acid rain and will receive much more stress with the increase of acid rain precursors.