• Korean Journal of Construction Engineering and Management
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• v.14 no.6
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• pp.70-77
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• 2013

Construction industry is broadly agreed as one of the most important sectors of any economy around the world. In this paper, time series data of Korean construction industry and Korean economy are examined. The Bon's proposition will be inspected for Korean context using both cross-sectional and longitudinal analyses. The analysis of the longer than four decades national account statistic of the Korean macro economy verify Bon's proposition of an inverted U-shaped relationships. The verified U-shaped relationships for Korean context exist not only in terms of the construction share in total GDP but also in terms of total construction volume as an economy develops from LDC to NIC and then to AIC eventually with time. The results of the thesis show that the contribution towards the macro economy has varied across different stages of development.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.355-355
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• 2007

염료감응형 태양전지(Dye-sensitized Solar Cell; DSSC)의 에너지 변환효율을 높이기 위해 유리분말을 첨가하여 빛의 분산특성 및 빛의 이용률을 높이고 있지 알아보자고 실험을 하였다. 저온소성용, 고온소성용 두 가지 유리 분말을 각각 첨가한 경우 TiO2 광전극 박막표면에 유리분말의 잔류로 인한 영향을 X-RD로 분석 하였고 박막의 입자들의 형상변화와 분포를 알아보기 위해 FE-SEM으로 관찰하였으며 유리분말의 첨가량 별 광전류-전압 곡선으로부터 최적의 첨가량을 확인하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.56.2-56.2
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• 2011

고효율 염료감응 태양전지를 제작하기 위해 Sol-gel법을 사용하여 $TiO_2$ 분말을 제조하였다. 제조 과정 중 다양한 양의 nitric acid를 첨가하여 pH를 조절하였다. Sol-gel법을 위한 출발 물질로 titanium (IV) isopropoxide(TTIP)와 DI water를 사용하였으며 nitric acid은 0, 0.05, 0.1, 0.15의 몰비(nitric acid/TTIP)로 첨가하였다. 첨가한 결과 pH는 $22^{\circ}C$에서 각각 5.52, 2.26, 1.68, 1.38이었다. 얻어진 $TiO_2$ 콜로이드 용액은 결정성 있는 분말로 제조 후 $5{\times}5[mm^2]$ 크기의 염료감응 태양전지를 제작하는데 사용 되였다. $TiO_2$의 결정구조 및 형태는 cell의 XRD와 FE-SEM으로 분석되었고 전기화학적 특성을 분석하기 위해 irradiation of AM 1.5 ($100mW/cm^2$) simulatedsunlight에서 I-V 곡선을 측정하였다. 측정 결과 몰비(nitric acid/TTIP) 0.05, pH가 2.26일 때 가장 우수한 효율 특성을 보였다.

• Korean Journal of Food Science and Technology
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• v.25 no.1
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• pp.63-68
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• 1993

Heat penetration characteristics of retort pouched curry were studied to determine optimal sterilization conditions. Heating curve of retort pouched curry showed a simple logarithmic curve. The $f_h$ value (min.) of solid part in retort pouched curry was 1 min. higher than that of liquid part. $f_h$ value (min.) and $j_h$ value (heating lag factor) ranged from 8.3 min. to 12 min. and 1.0 to 1.17 respectively with increasing the ratio of solid to liquid and viscosity. $f_h$ value (min.) and $j_h$ value were significantly increased from 7.4 min. to 12.6 min. and 1.0 to 1.14 respectively with increasing thickness of the pouch from 11 to 15 mm. The low and medium volatile aroma components of retort pouched curry decreased during sterilization, which increased the high volatile aroma components. The retort pouched curry processed at $120^{\circ}C$, for 24 min. with $F_o$, value of $8{\sim}9$ could keep up a desirable quality without any remarkable deterioration.

• Analytical Science and Technology
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• v.25 no.6
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• pp.476-482
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• 2012

Asian dust particles are known to have sizes ranging from a few nanometers up to about a few micrometers. The environmental and health effects depend on the size of the dust particles. The smaller, the farther they are transported, and the deeper they penetrate into the human respiratory system. Sedimentation field-flow fractionation (SdFFF) provides separation of nano to microparticles using a combination of centrifugal force and parabolic laminar flow in a channel. In this study, the steric mode of SdFFF (Sd/StFFF) was tested for size-based separation and characterization of Asian dust particles. Various SdFFF experimental parameters including flow rate, stop-flow time and field strength of the centrifugal field were optimized for the size analysis of Asian dust. The Sd/StFFF calibration curve showed a good linearity with $R^2$ value of 0.9983, and results showed an excellent capability of Sd/StFFF for a size-based separation of micron-sized particles.The optical microscopy (OM) was also used to study the size and the shape of the dust particles. The size distributions of the samples collected during a thick dust period were shifted towards larger sizes than those of the samples collected during thin dust periods. It was also observed that size distribution of the sample collected during dry period shifts further towards larger sizes than that of the samples collected during raining period, suggesting the sizes of the dust particle decrease during raining periods as the components adsorbed on the surface of the dust particles were removed by the rain water. Results show Sd/StFFFis a useful tool for size characterization of environmental particles such as the Asian dust.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.50 no.6
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• pp.419-427
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• 2005

For the purpose to verify the physico­chemical properties of Korean waxy wheat, comparative analyses between waxy wheat lines and their respective maternal parents were performed on mixing and pasting properties, and flour particle sizes. The particle sizes of waxy wheat flour were significantly larger than those of their parents when milled in a same condition. Although the protein contents of flour in waxy wheat lines tested were high as much as those of bread wheat, the quality parameters showed lower baking uses based on sedimentation volumes and mixing characteristics. Waxy flour required more water than non-waxy flour to obtain the proper mixogram. Waxy wheat flour showed more or less higher onset pasting temperatures and much higher breakdown viscosities than their respective parent flour in the Rapid Viscograph test. Moreover, peak viscosity temperatures and final viscosities were dramatically reduced in waxy wheat lines by showing $79.4 - 81.7^{\circ}C$ and 101 ­116.9 RVU, respectively, compared to their parents in that the temperatures above $95^{\circ}C$ and the viscosity ranges of 148 -171.8 RVU.

• Korean Journal of Ecology and Environment
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• v.46 no.2
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• pp.215-224
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• 2013

We clarified the background for establishment of vegetation by comparing the spatial distribution maps of vegetation and substrate on a gravel bar in the Bangtae stream located on Inje-gun of Gangwon-do, the central eastern Korea. The total vegetation coverage was higher in the interior and lower in the marginal parts of the gravel bar. Spatial distribution of vegetation on the longitudinal section of the gravel bar tended to be arranged in the order of shrub, subtree, and tree dominated vegetation types from the front (upstream) toward the rear (downstream) parts. Coverage of the herbaceous plants was higher in the central and rear parts and lower in the front and right parts of the gravel bar. Vegetation height was higher in the rear part and became lowered as move toward the front part. Substrate was distributed in the order of boulder, gravel, sand, and boulder from the front toward the rear parts. Ordination of stands based on vegetation data was arranged in the order of annual plant, perennial herb, shrub, and tree dominated vegetation as move from the right to the left parts on the axis I. Species richness was higher in the order of Pinus densiflora community, Phragmites japonica community, Salix gracilistyla community, Fraxinus rhynchophylla community, annual plant dominated vegetation, and Prunus padus for. padus community based on the species rank-abundance curve. The order based on the Shannon's index was some different; diversity of Phragmites japonica community and Salix gracilistyla community, which showed higher dominance degree, were low differently from species richness. In conclusion, it was evaluated that the gravel bar newly established toward the upstream and vegetation dynamics of the gravel bar seemed to follow ecosystem mechanisms of succession. As were shown in the above results, the Bangtae stream corresponded to the upstream and thereby particle size of substrate was big. Therefore, they move by rolling and are accumulated for the upstream. Vegetation types were arranged in the order of woodland, shrub-land and grassland from the rear toward the front parts of the gravel bar and thereby reflected the formation process of the bar. However, the gravel bar is disturbed frequently by not only the running water but also the suspended sand as the dynamic space. Such disturbances cause habitat diversity and consequently led to high biodiversity.