• International Area Studies Review
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• v.18 no.3
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• pp.23-46
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• 2014

Applying the dynamic shift-share analysis, this paper decomposes inflow of foreign direct investment (FDI) of Korea for the period of 2003-2012 into three components: world growth effect, industry-mix effect and competitive effect. Taking the group of developed countries as population for comparison, this paper finds that Korea has been lagging behind the group of developed countries in attracting FDIs, thereby having recorded negative aggregate industry-mix effects and negative aggregate competitive effects as well. However, the following industries have recorded positive competitive effects: textiles, chemicals, electrical and electronic equipment, motor vehicles and other transport equipment, hotels and restaurants and business services. Moreover, in the sub-period of 2008-2012, positive competitive effects have been recorded for most manufacturing industries. This reflects the fact that inward FDI into Korea has not been affected much by the financial crisis of 2009.

• Journal of the Economic Geographical Society of Korea
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• v.24 no.2
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• pp.143-162
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• 2021

This study reviews the progress of maquiladora industry in Mexico and the development of the IMMEX program. The maquiladora program allows foreign-invested factories in Mexico to import raw materials and components duty free and to export the finished products to the U.S. It contributed to the increase in employment and population of border cities. Low wage level of Mexico induced not only standardized labor-intensive industries but also the high-tech automated industries requiring assembly process. In 2006, the Mexican government merged the maquiladora program and PITEX for Mexican export-oriented firms into a single new program, the IMMEX program, in order to promote exports more efficiently. This study presents the distributions of the IMMEX firms by industrial sector and by region. It is revealed that transport equipment sector leads the export industries in Mexico, and Tijuana and Juárez accommodate largest agglomerations of the IMMEX firms.

• Journal of the Economic Geographical Society of Korea
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• v.25 no.2
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• pp.203-218
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• 2022

The global value chain, as a major feature of the contemporary global economic system, has been mainly led by developed countries. Whereas developing countries have taken the relatively low value-added activities and this made geographical imbalances in value distribution. This imbalance in value distribution, however, began to gradually alleviated. Related to this phenomenon, the purpose of this research is to analyze the factors affecting factors. Focused on the method of upgrading the industry in the global value chain, the impact on the acquisition of value-added in developing countries was analyzed among the various factors to achieve the research purpose. Panel analysis was conducted on all industries, food and tobacco industries, textile and clothing industries, computer and electornics industries, and automobile industries of the OECD Value-Added Trade Data (TiVA). As a result of the analysis, it was confirmed that in all industries, value-added acquisition in developing countries was improved by increased total production, high value-added product production and participation in early stage. The analysis results by detailed industry showed slightly different patterns depending on the characteristics of each industry.

• The Korean Journal of Mycology
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• v.15 no.2
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• pp.80-86
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• 1987

The author isolated high cellulolytic fungi from natural sources and determined optimal condition of protoplast formation and fusion as fundamental step for improvement of the isolated it's cellulolytic ability. Three different cellulolytic fungi, such as Aspergillus sp., Penicillium sp. and Trichoderma sp., were isolated from soil. Their cellulolytic activities were compared with that of Aspergillus niger which was useful industrially and had cellulase activity. It was Aspergillus sp. that showed the highest activity of all these four fungi. And then it was followed by Penicillium sp., Trichoderma sp., and Aspergillus niger in order. An auxotrophic mutant of Aspergillus sp. was obtained by UV mutagenesis method. Having try to produce protoplast from mycelia, the author found that ${\beta}-glucuronidase$, at pH 6.0, was effective cell-wall lytic enzyme. And the optimal concentration of this enzyme was 5,000 unit/ml. Regeneration rates of wild type, met. auxotroph and arg. auxotroph, in presence of osmotic stabilizer, were 7. 0%, 7. 5% and 5.2%, respectively. PEG with M.W. 6,000 was effective stimulator for protoplast fusion in the concentration of 30% (W IV). In such a condition, we obtained 1.2% cell fusion rate.

• Korean Journal of Food Science and Technology
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• v.35 no.5
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• pp.849-855
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• 2003

The extrusion effects on solubilization of brown rice, glutinous rice, barley and job's tear were investigated in comparison with raw and roasted whole grains. Whole grains were extruded under 13 different operating conditions, where the process variables were controlled in the following ranges: screw speed, $200{\sim}300$ rpm; temperature, $110{\sim}130^{\circ}C$; moisture, $15{\sim}25%$. Solubilization effects of whole grains by extrusion were characterized in terms of water solubility index (WSI), viscosity, dispersibility and dietary fiber in comparison with those of raw and roasted grains. WSI of whole grains significantly increased by extrusion, especially WSI of glutinous rice containing abundant amylopectin increased twice than WSI of brown rice. The content of soluble dietary fiber was increased due to extrusion treatment, while insoluble dietary fiber decreased concomitantly and the content of total dietary fiber was not nearly changed. Extrusion improved the dispersibility and swelling effects in comparison with that of raw and roasting grains.

• Journal of the Korea Institute of Building Construction
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• v.24 no.2
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• pp.203-213
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• 2024

This study delves into the mechanical properties of fiber-reinforced cement composites(FRCC) concerning the dispersion method of multi-walled carbon nanotubes(MWCNTs). MWCNTs find utility in industrial applications, particularly in magnetic sensing and crack detection, owing to their diverse properties including heat resistance and chemical stability. However, current research endeavors are increasingly directed towards leveraging the electrical properties of MWCNTs for self-sensing and smart sensor development. Notably, achieving uniform dispersion of MWCNTs poses a challenge due to variations in researchers' skills and equipment, with excessive dispersion potentially leading to deterioration in mechanical performance. To address these challenges, this study employs ultrasonic dispersion for a defined duration along with PCE surfactant, known for its efficacy in dispersion. Test specimens of FRCC are prepared and subjected to strength, drawing, and direct tensile tests to evaluate their mechanical properties. Additionally, the influence of MWCNT dispersion efficiency on the enhancement of FRCC mechanical performance is scrutinized across different dispersion methods.

• Journal of the Economic Geographical Society of Korea
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• v.23 no.2
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• pp.147-165
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• 2020

The aim of this study is to find out Korean electronic industries' production network in Hanoi Red River Delta, Vietnam and its change based on customer-following overseas expansion. In-depth interviews with Korean subcontractors were conducted to examine the characteristics of customer-following overseas expansion of Korean subcontractors. Korean subcontracting corporations in electronic industries have expanded into Vietnam as the suppliers to Korean transnational corporations. Since 1990s, Korean corporations have invested into Vietnam but since late 2000s its industrial and geographical concentration has been shifted from textile and clothing industries in Southern Vietnam to electronics in Northern Vietnam. The customer-following overseas expansion of the subcontractors has emerged in three aspects: physical proximity, asymmetrical inter-firm relations and organizational embeddedness. During the process of customer-following overseas expansion, Korean electronic industry production network was transplanted into Vietnam and partially modified. This is because the company's hierarchy and difficulties in changing its trading relationship have affected the process of advancing into overseas markets. Korean transnational corporations seek to establish a stable suppliers through expansion accompanying with its subcontractors, and providing financial and non-financial support to its subcontractors.

• Journal of Radiation Industry
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• v.6 no.1
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• pp.61-65
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• 2012

Polyacrylonitrile (PAN) is one of the most widely used precursor polymers for making high performance carbon fibers. Conversion of PAN fibers to good quality carbon fibers requires an essential stabilization step prior to carbonization. Electron beam irradiation is an excellent technique for modifying the physical properties of materials. This study aimed to elucidate the effects of electron beam irradiation on the stabilization reactions of PAN nanofibers. FT-IR analysis indicated that the stabilization of irradiated PAN nanofibers was initiated at a lower temperature. The TG curve of PAN nanofibers showed a significant decrease of weight loss step between 280 and $320^{\circ}C$. In the case of irradiated PAN nanofibers, weight loss sudden weight did not loss occurs.

• Journal of Radiation Industry
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• v.5 no.1
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• pp.41-46
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• 2011

Polyacrylonitrile (PAN) fibers are the most widely used precursor of the materials for carbon fibers. The conventional process of carbon fibers from PAN precursor fiber includes two step; stabilization at low temperature and carbonization at high temperature. Compared to thermal stabilization, the stabilization process by electron beam (E-beam) irradiation is a advanced and brief method. However, a stabilization by E-beam irradiation was required a high dose (over 5,000 kGy) and spend over 1.5 hr (1.14 MeV, 1 mA). In the present work the main goal is exploring a quick stabilization process by cotrolling E-beam currents. The effect of various E-beam currents on stabilization of PAN precursor fiber was studied by gel fraction test, thermo gravimertic analysis (TGA), differential scanning calorimetry (DSC), tensile strength, and scanning electron microscopy (SEM) images.

• Journal of Radiation Industry
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• v.9 no.1
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• pp.15-20
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• 2015

Carbon fiber has received much attention owing to its properties, including a large surface-to-volume ratio, chemical and thermal stability, high thermal and electrical conductivity, and high mechanical strengths. In particular, magnetic nanopowder dispersed carbon fiber has been attractive in technological applications such as the electrochemical capacitor and electromagnetic wave shielding. In this study, the nickel-oxide-nanoparticle dispersed polyacrylonitrile (PAN) fibers were prepared through an electrospinning method. Electron beam irradiation was carried out with a 2.5 MeV beam energy to stabilize the materials. The samples were then heat-treated for stabilization and carbonization. The nanofiber surface was analyzed using a field emission scanning electron microscope (FE-SEM). The crystal structures of the carbon matrix and nickel nanopowders were analysed using X-ray diffraction (XRD). In addition, the magnetic and electrical properties were analyzed using a vibrating sample magnetometer (VSM) and 4 point probe. As the irradiation dose increases, the density of the carbon fiber was increased. In addition, the electrical properties of the carbon fiber improved through electron beam irradiation. This is because the amorphous region of the carbon fiber decreases. This electron beam effect of PAN fibers containing nickel nanoparticles confirmed their potential as a high performance carbon material for various applications.