• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.65-68
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• 2003

The paper discusses the use of stable emulsion, prepared by membrane emulsification technology, to improve the enantiocatalytic performance of immobilised lipase in multiphasic membrane reactors. The production of optical pure (S)-naproxen from racemic naproxen methyl ester has been used as model reaction system. The enzyme was immobilised in the sponge layer (shell side) of capillary polyamide membrane with 50 kDa cut-off, The O/W emulsion, containing the substrate in the organic dispersed phase, was fed to the enzyme membrane reactor from shell-to-lumen. The results evidenced that lipase maintained stable activity during all the operation time (more than 250 hours), showing an enantiomeric excess (96 $\pm$2%) comparable to the free enzyme (98 $\pm$ 1%) and much higher compared to similar lipase-loaded membrane reactors used in two-separate phase systems (90%). The study showed that immobilised enzymes can achieve high stability as well as high catalytic activity and enantioselectivity.

• Journal of Korea Trade
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• v.27 no.5
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• pp.113-136
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• 2023

Purpose - Global production chains and their impacts on economic growth have drawn extensive attention from researchers. Close relationships among global production chains, export and economic growth have been illuminated, as evidenced by the fast and stable economic growth of East Asian economies. These economies perform various roles within global production chains using offshoring, in which the impact of import on domestic gross output is as strong as that of export. The impact of import on economic growth would depend on whether imported inputs substitute or complement domestic inputs production, which is likely to vary according to individual countries' functions within global production chains. The economic growth of concerned countries would also be diverse. However, little attention has been paid to the impact brought by imports compared to its significance. Design/methodology - The principal methodology used in this paper is structural decomposition analysis (SDA), widely chosen to elucidate the impact of various factors on domestic gross output using input-output tables. This paper extracts trade data of six Asian economies from the World Input-Output Database (WIOD) 2016 release that covers 43 countries for the period 2000-2014. The extracted data is then categorised into 37 sectors. First, this paper calculates the Feenstra-Hanson Offshoring Index (OSI) of each country. It then applies SDA to measure the changes in each economy's gross output, export, import input coefficients, and domestic input coefficients. Finally, after taking the first difference from pooled time-series data, it estimates the correlations between imported input coefficients and OSI using the ordinary least square (OLS) method. Findings - The main findings of this paper can be summarised as follows. Firstly, all six countries have increasingly engaged in global production chains, as evidenced by the growing size of OSI. Secondly, there are negative correlations in five countries except Japan, with sectoral differences. Thirdly, changes in import input coefficients are not negative in all six countries, indicating that offshoring does not necessarily substitute for domestic inputs production but does complement it and, therefore, fosters their economic growth. This is observed in China, Indonesia, Korea and Taiwan. Offshoring has led to an increase in the use of imported inputs, which has, in turn, stimulated domestic inputs production in these countries. Originality/value - While existing studies focus on the role of export in evaluating the impact of participating global production chains, this paper explicitly examines the unexplored impact of import on domestic gross output by considering both the substitution and the complementary effect, using the WIOD. The findings of this paper suggest that Asian economies have achieved fast and stable economic growth not only through successful export management but also through effective import management within global production chains. This paper recommends that the Korean government and enterprises carefully choose offshoring strategies to minimise disruption to domestic production chains or foster them.

• Biotechnology and Bioprocess Engineering:BBE
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• v.4 no.1
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• pp.41-45
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• 1999

Microbial cellulose has many potential applications due to its excellent physical properties. The production of cellulose from Acetobacter xylinum in submerged culture is, however, beset with numerous problems. The most difficult one has been the appearance of negative mutants under shaking culture conditions, which is deficient of cellulose producing ability. Thus genetic instability of Acetobacter xylinum under shaking culture condition made developing a stable mutant major research interest in recent years. To find a proper type of bioreactor for the production of microbial cellulose, several production systems were developed. Using a reactor system with planar type impeller with bottoms sparging system, it was possible to produce 5 g/L microbial cellulose without generating cellulose minus mutants, which is comparable to that of static culture system.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.329-331
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• 2000

A marine bacterium, Pseudomonas aeruginosa BYK-2 KCTC 18012P was immobilized in modified polyvinyl alcohol for the continuous production of rhamnolipids. The stability of rhamnolipids production, the mechanical strength of beads and the scanning electron microscope of immobilized cell were determined in a repeated batch culture. The rhamnolipids production was maintained $80{\sim}90%$ stability of initial production, and the mechanical strength also was stable during the repeated batch culture more than 14 cycles. In the case of SEM studies, the internal distribution pattern of the cell entrapped in modified PVA beads was observed. On the basis of optimal conditions, the continuous culture was investigated in 1.8L air lift bioreactor. The result suggested 0.1g/h rhamnolipids was obtained from 1%(v/v) fish oil continuously in conditions of 1.2L working volume, 0.5vvm and 20ml/h flow rate.

• Journal of the Korean Regional Science Association
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• v.11 no.2
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• pp.1-17
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• 1995

Regional production structres are investigated through an estimation of three-input(labor, capital and material) translog cost function. The estimation uses the pooled data in which time series data of 1970-1990 are combined with cross-sectional data corresponding to firm sizes. The empirical finding are the following: (1) the factors are Allen substitutes each otner in general except Pusan and a couple of regionss, and (2) estimates are very small in its absolute value irrespective of the regions. The low elasticity estimates of this study implies that substitytability among the three inputs are very weak in the regional manufacturing production compared to that in the national production. Seoul-Kyungki metropolitan area produces not only the smallest elasticities but relatively stable estimates without much fluctuation between the sub-regions of the area.

• Journal of Microbiology and Biotechnology
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• v.5 no.3
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• pp.172-176
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• 1995

Citrate is mainly produced from fungi and oxygen transfer has been known as one of the important factors in citric acid production. A bubble column bioreactor was used for citrate production after pellet was initially made using a stirred bioreactor for the inoculation. The relationship between the pellet size of Aspergillus niger and the oxygen transfer was elucidated by considering morphological characteristics of the pellet. The pellet size was determined by adjusting the impeller speed in the stirred bioreactor and the optimum diameter of the pellet was observed to be 2.2 mm under the experimental conditions. Pellet was maintained quite stable in the bubble column bioreactor and production of citric acid was significantly improved by maintaining optimal pellet conditions in the bubble column bioreactor.

• Journal of the Korean Data and Information Science Society
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• v.17 no.1
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• pp.63-76
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• 2006

Marine production forecasting in fisheries is a crucial factor for managing and maintaining fishery resources. Thus this paper aims to generate a forecasting model of total marine production. The most generally method of time series model is to generate the most optimal single forecasting model. But the method could induce a different forecasting results when it does not properly infer a model To overcome the defect, I am trying to propose a single forecasting through multiple time series model. In other word, by comparing and integrating the output resulted from ARIMA and VAR model (which are typical method in a forecasting methodology), I tried to draw a forecasting. It is expected to produce more stable and delicate forecasting prospect than a single model. Through this, I generated 3 models on a yearly and monthly data basis and then here I present a forecasting from 2006 to 2010 through comparing and integrating 3 models. In conclusion, marine production is expected to show a decreasing tendency for the coming years.

• Korean Journal of Food Science and Technology
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• v.9 no.1
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• pp.31-35
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• 1977

As a study on the acid protease production by Rhizopus japonicus S-62, the culture conditions for the enzyme production and characteristics of the crude enzyme were investigated. The results are summarized as follows: 1. The optimum conditions for solid culture on wheat bran were 48 hrs of culture period and $100{\sim}120%$ addition of tap water. 2. Of the several media, wheat bran medium was the most excellent in the enzyme production. 3. The addition of sucrose, fructose, $NH_4Cl$ and $NaH_2PO_4$ on wheat bran, respectively, increased largely the enzyme production. 4. The optimum pH for the enzyme action was pH $2.4{\sim}2.6$, the optimum temperature was about $40^{\circ}C$, and the stable pH range was $pH\;2.5{\sim}5.0$, the enzyme was stable below $40^{\circ}C$ and was inactivated abruptly above $40^{\circ}C$.

• Journal of the Korea Society of Computer and Information
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• v.28 no.7
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• pp.57-65
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• 2023

Various studies to enhance the accuracy of rice production forecasting are focused on improving the accuracy of the models. In contrast, there is a relative lack of research regarding the data itself, which the prediction models are applied to. When applying the same dependent variable and prediction model to two different sets of rice production data composed of distinct features, discrepancies in results can occur. It is challenging to determine which dataset yields superior results under such circumstances. To address this issue, by identifying potential influential features within the data before applying the prediction model and centering the modeling around these, it is possible to achieve stable prediction results regardless of the composition of the data. In this study, we propose a method to adjust the composition of the data's features in order to select optimal base variables, aiding in achieving stable and consistent predictions for rice production. This method makes use of the Korea Meteorological Administration's ASOS data. The findings of this study are expected to make a substantial contribution towards enhancing the utility of performance evaluations in future research endeavors.

• Journal of the Korean Society of Combustion
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• v.15 no.3
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• pp.74-81
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• 2010

In this study, soot formation characteristics on the instability of laminar diffusion flames were investigated experimentally using a concentric co-flow burner. When a small amount of air was supplied through an inner nozzle, a stable propane laminar diffusion flame became unstable and began to oscillate mainly due to the dilution effect. The increase of air flow rate transformed an oscillating non-sooting flame into a stable nonsooting flame. When the air flow rate was continuously increased an inner flame was formed and the flame was changed to an oscillating sooting flame, an oscillating non-sooting flame and finally a stable non-sooting hollow flame. When the air flow rate was decreased, a non-sooting hollow flame was eventually changed back to a stable non-sooting flame. The presence of an inner flame, however, altered the soot formation characteristics of a flame. More soot production was observed with the presence of an inner flame. The increased or decreased soot formation/oxidation rates, the radiation heat loss, and the heating effect of inner flames are most likely to be responsible for the observed instability of laminar diffusion flames.