• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 1999.04b
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• pp.254-258
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• 1999

The distribution of anionic groups in the fibers, the fines, the colloidal fraction and the dissolved fraction, respectively, of thermomechanical pulp (TMP) suspensions was determined and peroxide bleaching of spruce TMP were also studied. Spruce TMP was extracted with hexane, treated with alkali, or bleached with peroxide. Suspensions made at pH 5.5 were fractionated into long fibres, large fines, small fines, a colloidal fraction and a dissolved fraction. The charge of the fractions was determined using polyelectrolyte titration. To determined the origin of the charges, the contents of fatty acids, resin acids and acidic units in hemicelluloses in the different fractions were determined by has chromatography. Extraction of TMP with hexane prior to fractionation increased the measured charge of the fibres. The removal of the wood resin probably uncovered some carboxyl groups on the fibre surfaces, or improved th e penetration of polybrene into the pores of the fibres. The charge of the fines and the colloidal fraction was lower when the wood resin had been removed. Alkaline treatment of the TMP increased the charge of the fibres and fines, mainly because of demethylation of pectins. Alkaline treatment increased the charge also of the dissolved fraction, because of the release the charge also of the dissolved fraction, because of the release of pectic acids into the water phase. Alkaline peroxide bleaching further increased the charge of fibres and the dissolved fraction, most likely because of lignin oxidation. The charge of the colloidal fraction, consisting mainly of wood resin, was only slightly affected by alkaline treatment and peroxide bleaching. The anionic groups in TMP suspensions were mainly free uronic acids in the hemicelluloses. The contribution from the fatty and resin acids was substantial only for the colloidal fraction.

• Journal of the Korean Society for Railway
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• v.9 no.1 s.32
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• pp.36-42
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• 2006

Studied was a strategic plan for the Korean High-Speed Train system to penetrate the Chinese railway market in exchange of the technology of KHST. Firstly, taken was a glance at Chinese Government plans to extend total length of his railway lines and to construct the Beijing~Shanghai high-speed railway line. Then, disparity of railway technology in Korea and China was reviewed. From the review, SWOT Analysis were carried out to penetrate the foreign markets. Countermeasures to cope with SWOT were also considered. Strategical governmental supports and the establishment of the special organization to be in charge of penetration of KHST into foreign markets were proposed. Finally, also proposed was the transfer of KHST technology to Chinese counterparts in exchange of tangible benefits for Korean side. The benefits may include (1) adoption of KHST as the type of rolling stock for the Beijing~Shanghai line, (2) guarantee of participation in the project and royalty for the KHST technology used for the future high-speed railway line construction, (3) prior written approval and partnership when making its way to third country, and (4) participation of Korean construction companies in Chinese railway construction project, etc. Adoption of KHST in China indeed gives chance to integrate the high-speed railway network after reunification of Korean peninsular, and enhance the economic ties between two countries.

• Journal of ILASS-Korea
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• v.23 no.1
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• pp.22-29
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• 2018

The purpose of this study is to investigate the macroscopic spray characteristics and spray pattern of a gasoline direct injection (GDI) injector according to the increase of injection pressure. The macroscopic spray characteristics, such as a spray tip penetration and spray angle, were measured and analyzed from the frozen spray images, which are obtained from the spray visualization system including the high-speed camera, light-source, long-distance microscope (LDM). The spray pattern was analyzed through the deviation of the center of the spray plum and images were acquired using Nd: YAG Laser and ICCD(Intensified charge coupled device) camera. From the experiment and analysis, it revealed that the injection pressure have a significant influence on the spray tip penetration and spray pattern. However, the injection pressure have little influence on the spray angle. The increase of injection pressure induced the reduction of a closing delay. In addition, the deviation of spray center increase with the increase of injection pressure and the distance from a nozzle tip.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.907-914
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• 2005

Studied was a strategic plan for the Korean High-Speed Train system to penetrate the Chinese railway market in exchange of the technology of KHST. Firstly, taken was a glance at Chinese Government plans to extend total length of his railway lines and to construct the $Beijing\~Shanghai$ high-speed railway line. Then, disparity of railway technology in Korea and China was reviewed. From the review, SWOT Analysis were carried out to penetrate the foreign markets. Countermeasures to cope with SWOT were also considered. Strategical governmental supports and the establishment of the special organization to be charge of penetration of KHST into foreign markets were proposed. Finally, also proposed was the transfer of KHST technology to Chinese counterparts in exchange of tangible benefits for Korean side, The benefits may include (1) adoption of KHST as the type of rolling stock for the $Beijing\~Shanghai$ line, (2) guarantee of participation in the project and royalty for the KHST technology used for the future high-speed railway line construction. (3) prior written approval and partnership when making its way to third country, and (4) participation of Korean construction companies in Chinese railway construction project. etc. Adoption of KHST in China indeed gives chance to integrate the high-speed railway network after reunification of Korean peninsular, and enhance the economic ties between two countries.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.256-257
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• 2011

The development for Eco-friendly cars has been expanded as the concern about environmental pollution and a rise in gas prices. The Electric Vehicle(EV) and Plug in Hybrid Electric Vehicle(PHEV) are generally connected on distribution power systems to charge the traction batteries. The growing number of EV/PHEVs could have a effect on distribution power systems and result in overload of power utilities and power quality problems. In order to reduce the adverse effect on distribution power systems, the influence of electric vehicle loads should be evaluated. In this paper, the influence of electric vehicle loads is evaluated by using OpenDSS(Open Source Distribution System Simulator) according to the penetration rate of electric vehicle.

• The Journal of the Korea Contents Association
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• v.13 no.8
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• pp.360-370
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• 2013

As the mobile telecommunications service market grows rapidly, interconnection opportunities from the fixed network to the mobile network increase and the land-to-mobile (LM) interconnection charge becomes critical factor in competition between fixed and mobile telecommunications service providers. This paper aims to evaluate the LM interconnection charge level in Korea in comparison with those of 36 foreign countries and suggest the regression model for the LM interconnection charge. Based on the regression analysis, we found that regulation, GDP per capita, wire telephone penetration, liberalization are identified as significantly affecting factors on the LM interconnection charge level, and the level of the LM interconnection charge is comparatively low.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.2239-2244
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• 2003

A new stratified charge combustion system has been introduced and developed for GDI engines. Before this new GDI system, the stratified mixture was formed by a high pressure swirl injector. But, the special feature of new system is employed of a thin fan-shaped fuel spray formed by a slit type nozzle. Also, this system has been adopted a shell-shaped piston cavity. We made high pressure gasoline injection system and investigated the fan-shaped spray characteristics such as spray tip penetration, spray angle, SMD and velocities of droplets using PDPA(Phase Doppler Particle Analyzer) system and spray visualization system to obtain the concept of the new design and the fundamental data for the next generation GDI system. The experiment was performed at the injection pressures of 5 and 9MPa under the atmospheric condition.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.341-344
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• 1999

In the case of the offshore concrete structures like the anchorage block of a suspension bridge of Kwangan Grand Road, there is a need of the concrete which has low heat of hydration and good resistance for sea-water attack. In this study, the blended super low heat cement which satisfies that requirement was developed and several tests were carried out. The concrete using the blended super low heat cement showed lower adiabatic temperature rise than 3$0^{\circ}C$ and good early strength. Also, its passed charge(coulomb) to resist chloride ion penetration was very low.

• 한국연소학회:학술대회논문집
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• 2003.12a
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• pp.231-236
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• 2003

HCCI(Homogeneous Charge Compression Ignition) combustion is an advanced combustion process explained as a homogeneously premixed charge of a fuel where air is admitted into the cylinder and compression ignited. It has possibility to reduce NOx by spontaneous auto-ignition at multiple points that allows very lean combustion resulting in low combustion temperatures. Particulate matters (PM) could be also reduced by the homogeneous combustion and no fuel-rich zones. Injection timing is extremely advanced to achieve homogeneous charge where a diesel fuel could not be vaporized sufficiently due to low pressure and low temperature condition. Also the over-penetration could be a severe problem. The small injection angle and multi-hole injectors were applied to solve these problems. Dimethyl ether (DME) as an altenative fuel was also applied to relive the bad vaporization problem associated with early injection of diesel fuel. Neat DME has a very high cetane rating and high vapor pressure. Contained oxygen reduces soot during the combustion. Experimental result shows DME can be easily operated in an HCCI engine. PM shows almost zero value and NOx is reduced more than 90% compared to direct-injection diesel engine operating mode but problem of early ignition needs more investigation.

• Journal of the Korea Concrete Institute
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• v.16 no.3 s.81
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• pp.407-414
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• 2004

The purpose of this study is to evaluate the ability to resist chloride ions penetration of the concrete structure under marine environment in south-east asia especially. In this study, high strength concrete(HSC) with various combination of ordinary portland cement(OPC), blast-furnace slag(SG) and silica fume(SF) are cured 23 and $35^{\circ}C$ considering the site weather, and are cured in water for 3, 7 or 56 days respectively. And to investigate the fundamental properties and the resistance of chloride penetration of various HSC, setting time, slump flow, compressive strength, void and ASTM C 1202 test were conducted. Test results show that the compressive strength of HSC is similar regardless of SG replacement ratio and total charge passed of chloride is the smallest at 40% replacement of SG. The compressive strength of G4FS HSC is, besides, outstandingly high at early age compare with other HSC, but the compressive strength of G4F HSC, which is vary according to curing temperature and condition, most high at the age after 7 days. Total passed charge of HSC get larger in the order G4FS