• Journal of Navigation and Port Research
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• v.29 no.9
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• pp.795-800
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• 2005

Nowadays, road transportation which has played a key role in the market of both passenger and freight transportation is facing with a serious problem, the traffic congestion causing a delay of transportation. Therefore, railroad transportation is considered as an attractive alternative mode of inland transportation due to its inherent merits in mass transportation such as relatively low cost compared with road transportations, less air pollution and noise than other mode ets. In this paper, therefore, we examine the current situation of railroad transportation markets including TKR(Trans- Korean Railway}, TSR(Trans-Siberian Railway} and prospects for the connection of TKR-TSR. And then we examine the structure of the container transportation market by railroad in Korea with a brief analysis of the traffic volume of TKR-TSR.

• Journal of Nutrition and Health
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• v.26 no.4
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• pp.423-432
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• 1993

Feeding mode and evacuation pattern of 9 breast-fed(BF) infants and 22 formula-fed(FF) infants were monitored at 1, 2 and 3 months postpartum in Korea. The daily feeding volume to the BF infants was significantly less than that to the FF infants at 2 and 3 months postpartum. And the daily feeding voloume to the BF infants decreased significantly with age, whereas that to the FF infants increased significantly. These data indicated that the frequency of daily feeding decreased with age in bofy infants' intake per feeding increased whereas the BF infants' did not. As a result, the BF infants could not adjust their intakes. The frequency of daily evactation of the BF infants was higher than that of the FF infants, but the amount of daily evacuation of the BF infants was less than that of the FF infants.

• Journal of Environmental Science International
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• v.12 no.7
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• pp.791-799
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• 2003

This study was carried out to get more operational characteristics of the sequencing batch biofilm reactors with media volume/reactor volume ratio of 15 %, 25 % and 35 %. Experiments were conducted to find the effects of the media packing ratio on organic matters and nutrients removal. Three laboratory scale reactors were fed with synthetic wastewater. During studies, the operation mode was fixed. The organic removal efficiency didn't show large difference among three reactor of different packing media ratios. However, from the study results, the optimum packing media ratios for biological nutrient removal was shown as 25%. The denitrifying PAOs could take up and store phosphate using nitrate as electron acceptor.

• Membrane and Water Treatment
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• v.2 no.1
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• pp.63-74
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• 2011

A spiral wound nanofiltration (NF) membrane (GE Osmonics, DK 4040F) was used to remove pesticides from water. Several solutions of single pesticides and their mixtures were prepared. The pesticides initial concentration ranged from ca. 50 ng/L (single pesticide) to ca. 700 ng/L (as sum of 14 pesticides) and progressively increased with time since the NF experiments were carried out in a concentration mode up to a Volume Concentration Ratio, VCR = 10. Permeate flux and pesticides retention were evaluated as a function of the Volume Concentration Ratio. The permeate flux did not practically change by varying VCR. Pesticide retention was found to be around 97-98% both in the cases of single pesticide solutions and different mixtures of pollutants, and was not affected by the VCR. Pesticides concentration in permeate samples was found to be lower than the maximum concentration level fixed in European directive.

• Computers and Concrete
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• v.22 no.1
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• pp.1-10
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• 2018

In this study an implicit algorithm for modeling of propagation of macrocracks in 3D concrete structures suffering from alkali-silica reaction has been developed and implemented. The formulation of the problem prior to the onset of localized deformation is based on a chemo-elasticity approach. The localized deformation mode, involving the formation of macrocracks, is described using a simplified form of the strong discontinuity approach (SDA) that employs a volume averaging technique enhanced by a numerical procedure for tracing the propagation path in 3D space. The latter incorporates a non-local smoothening algorithm. The formulation is illustrated by a number of numerical examples that examine the crack propagation pattern in both plain and reinforced concrete under different loading scenarios.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.480-485
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• 2004

If a wall separates the bounded and unbounded spaces, then the wall's role in transporting the acoustic characteristics of the two spaces is not well defined. In this paper, we attempted to see how the acoustic characteristical of two spaces are really affected by the spatial characteristics of the wall. In order to understand coupling mechanism, we choose a finite space and a semi-infinite space separated by the flexible or rigid wall and an opening. A volume interaction can be occurred in structure boundary and a pressure interaction can be happened in the opening boundary. For its simplicity, without loosing generality, we use rather simplified rectangle model instead of generally shaped model. The source impedance is presented to the various types of boundaries. The distributions of pressure and active intensity are also presented at the cavity and structure-dominated modes. The resulting modification, shifts of mode1 frequencies and changing of standing wave patterns to satisfy both coupled boundary conditions and governing equations, are presented.

• English Language & Literature Teaching
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• v.18 no.3
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• pp.135-148
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• 2012

This is a retrospective, quantitative review of the English Teachers Association in Korea, namely the ETAK and its journals during the period of 18 years ever since the establishment in August 1994. It examines the history of the association, its domestic and international conferences, and most importantly, its articles. The purpose was to learn how it has emerged into a full-fledged organization, what the preferred language of the article has been, how the volume size has changed, and how many foreign scholars' articles have been contributed. It also looked into the number of authors each article was written by to examine the trend of cooperative work in the field of English education. Classification of the research topic was focused on the 4 skills of the language, grammar and vocabulary, literature, linguistics and all the rest areas were categorized into others. From the results of the study, suggestions for the future ETAK in the Korean English teaching were to be given.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.4
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• pp.311-316
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• 2003

Effects of pores on the microwave properties in microwave dielectric ceramics were studied by a computer simulation. Scattering matrix S$\_$21/ obtained from the network analyzer was compared to the S$\_$21/ obtained from the simulation. From electric field distribution, the dominant resonant TE$\_$01$\delta$/ mode could be easily determined. The effects of the porosity and pore size inside the dielectrics on the microwave properties were investigated by the HFSS simulation. When the total pore volume remains constantly, the quality factor decreased as the pore size Increases. As the total pore volume of the dielectrics increased. quality factor decreased.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.6
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• pp.1875-1881
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• 2016

The wear behavior for the two types of composites, those are epoxy matrix composites filled with silica particles and aluminium matrix composites filled with SiC particles, were compared to investigate the wear mechanism for these composites. Especially, the effect of the volume fraction for the epoxy matrix composites and the particle size for the aluminium matrix composites according to the apply load and sliding velocity were investigated. Wear tests of the pin-on-disc mode were carried out and followed by scanning electron microscope observations for the worn surface. The addition of the fillers in the composites were improved the wear resistance significantly and changed the wear mechanism for the both composites. These results were identified by the observation of the worn surface after testing.

• Structural Engineering and Mechanics
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• v.71 no.4
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• pp.407-416
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• 2019

Novel steel fibre reinforced ultra-lightweight cement composite (ULCC) with compressive strength of 87.3MPa and density of $1649kg/m^3$ was developed for the flat slabs in civil buildings. This paper investigated structural behaviours of ULCC flat slabs according to a 4-specimen test program under concentrated loading and some reported test results. The investigated governing parameters on the structural behaviours of the ULCC slabs include volume fraction of the steel fibre and the patch loading area. The test results revealed that ULCC flat slabs with and without flexure reinforcement failed in different failure mode, and an increase in volume fraction of the steel fibre and loading area led to an increase in flexural resistance for the ULCC slabs without flexural reinforcement. Based on the experiment results, the analytical models were developed and also validated. The validations showed that the analytical models developed in this paper could predict the ultimate strength of the ULCC flat slabs with and without flexure reinforcement reasonably well.