• Journal of the Korean Ceramic Society
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• v.43 no.11 s.294
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• pp.724-727
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• 2006

It has long been known that the oxidation kinetics of Zr-based alloys undergoes a crossover from parabolic to cubic in the pretransition period (before breakaway of the oxide scale). This kinetic crossover, however, is not fully understood yet. We have earlier proposed a model for the Zr-oxidation kinetics, in a closed form for the first time, by taking into account a compressive strain energy gradient as a diffusional driving force in addition to a chemical potential gradient of component oxygen across the ZrO$_2$ scale upon Zr [J. Nucl. Mater., 299 (2001) 235]. In this paper, we experimentally reconfirm the validity of the proposed model by using the thermogravimetric data on mass gain of Zr in a plate and wire form, respectively, in air atmosphere at different temperatures in the range of 500$^{\circ}$ to 800$^{\circ}C$, and subsequently report on the numerical values for oxygen chemical diffusivity and strain energy gradient across the oxide scale.

• The Journal of Industrial Distribution & Business
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• v.9 no.1
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• pp.25-38
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• 2018

Purpose - The purpose of this study is to empirically investigate the impact of donor's fiscal status on aid decisions before and after the 2008 global financial crisis. The effects on aid can change depending on the donor country's fiscal status and the period of financial crisis. Research design, data, and methodology - A fixed effect regression and dynamic panel GMM is conducted using a comprehensive dataset combining 31 donor and 167 recipient countries during 1996-2015. The key explanatory variable is central government debt-to-GDP ratio of donor country. Recipient countries' GNI per capita, population, governance indicators, and bilateral trade-to-GDP ratio between donor and recipient countries are included as control variables. Results - We can confirm the relationship between donor country's fiscal status and aid flow. The cyclical component of government debt is found to have a negative impact on grant decisions particularly after the 2008 global financial crisis. This effect becomes larger in the countries with high government debt-to-GDP ratio. ODA decisions from the countries with low financial constraint do not significantly affected by the recipient countries' factors such as GNI, population, and governance indicator. Conclusions - Based on the empirical results of this study, the source of aid should be diversified by incorporating private sector and innovative financing sources.

• Korean Journal of Poultry Science
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• v.35 no.1
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• pp.79-84
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• 2008

This study was conducted to investigate the effects of feeding herb extract (HE) on productivity, intestinal microflora and blood component profile in broiler chickens. A total of three hundred twenty, 1-d-old male chicks (Ross) were divided into 4 treatments with 5 replicates, 16 birds per replicate. Dietary treatments consisted of four diets; the corn-soybean based control diet, the diet containing HE 0.1%, the diet containing HE 0.2%, and the diet containing HE 0.4%. The Control diet contained 3,100, 3,100, 3,200 kcal/kg ME and 22%, 20%, 18% CP for starter ($0{\sim}2 wk$), grower ($3{\sim}5 wk$), and finisher ($6{\sim}7 wk$) periods, respectively. There were no significant differences in feed intake and BW gain among treatments in starter period. In grower period, the BW gain of HE 0.2%, and HE 0.4% were significantly higher (p<0.05) compared to Control. The 7-wk BW gain of HE 0.2% was significantly higher than Control (p<0.05). The feed intake tended to increase in HE 0.1%, but no difference was detected in feed conversion ratio among treatments. No significant differences were found in blood total cholesterol, triglyceride, HDL-cholesterol, glucose, total protein, and albumin among treatments, but total cholesterol in HE 0.4% decreased significantly as compared with Control. The cfu of Lactobacillus spp., yeast, and E. coli in the guts of chickens fed HE were not different form each other, but tended to increase as compared with Control.

• Korean Journal of Food Science and Technology
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• v.40 no.6
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• pp.656-660
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• 2008

Fermented soybean foods are an important component of the Korean diet. Eoyukjang is a type of traditional fermented soybean source. Microbial analysis of eoyukjang was conducted during the fermentation period in this study. Microorganisms isolated from eoyukjang were identified by biochemical tests and 16S rDNA sequencing. 17 different microorganisms, including bacteria, yeast, and fungi were detected in eoyukjang during the fermentation period. Even though Aspergillus participated in the early stage of fermentation of eoyukjang, Bacillus species and Saccharomyces cerevisiae were the major microzymes in eoyukjang throughout the maturation period. Eoyukjang is generally consumed after the boiling of the final sample. Therefore, the final sample of eoyukjang was boiled and analyzed. Our results showed that no vegetative microorganisms survived under the boiling conditions for eoyukjang. Fermented soybean products in the domestic market were also assessed for comparison with the results from eoyukjang. The total cell number of kanjang (soy sauce) samples was between 0 to 42 CFU/mL. The isolated microorganisms were identified as Bacillus species. All Bacillus isolates were not found to harbor the three enterotoxin-producing and emetic toxin-producing genes.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.2
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• pp.145-150
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• 1985

This study was conducted to examine the pharmacological effect of water soluble extract of Lichens (Parmelia, Physcia and Cladonia species) on liver-damaged rat by $CCl_4$ injection. Rat livers were damaged acutely and chronically by one-time injection of $CCl_4$ just prior to five days of experimental period and continuous injections in every three days for eight weeks of experimental period, respectively. During each period the experimental group was fed Lichens extract(5.5 mg of dry wt/ml) instead of water given to the control group. For both acute and chronic liver damage, the experimental group showed higher oxidative activity of hepatic mitochondria measured by state 3 respiration, P/O ratio, respiratory control and ATP synthesized, compard to the control group. Serum glucose was slightly higher in the experimental group but liver glycogen showed no significant difference between experimental and control groups. In experimental group, liver glucose-6-phosphatase activity was increased during first two days after acute liver damage, but not significantly different from control group during chronic damage. Liver lactate, malate plus fumarte and glutamate tended to be higher in the experimental group, especially for chronic liver damaged rat. It is concluded that Lichens extract stimulate cytoplasmic and mitochondrial oxidative activities and the possible mechanism of the latter is supposed to involve the preservation of membrane integrity by certain component(s) of water-soluble Lichens extract.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.3
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• pp.150-161
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• 2017

This study was conducted with the data of monitoring on soil chemical properties of rice paddy soils in Gyeongbuk Province. The selected soil chemical properties were analyzed every 4 year from 1999 to 2015. The soil pH measured in 2015 was higher than pH 6.0, which was 0.3-0.4 pH unit higher than data until 2007 survey year. The mean content of organic matter was greater than $24g\;kg^{-1}$ since 2003, but 35% of soil samples remained below the recommended level ($20-30g\;kg^{-1}$) in 2015. The mean concentration of available phosphate was maintained at $40mg\;kg^{-1}$ higher than the upper recommendation level ($80-120mg\;kg^{-1}$), and more than 40% of paddy soils tested were found to have less than the recommendation level during the survey period. The exchangeable K concentration ranged from 0.25 to $0.39cmol_c\;kg^{-1}$. Exchangeable Ca showed an average at the optimum range ($5.0-6.0cmol_c\;kg^{-1}$) during the monitoring period. Exchangeable Mg decreased linearly ($0.02cmol_c\;kg^{-1}\;year^{-1}$) from $1.55cmol_c\;kg^{-1}$ as of 1999 to below the lower level of the recommendation range ($1.5-2.0cmol_c\;kg^{-1}$). The amount of available $SiO_2$ was increased significantly from 2011 to over the recommendation level (${\geq}157mg\;kg^{-1}$). It was revealed that the soil chemical properties of rice paddy fields was influenced by topology, soil texture, type and region as result of principal component analysis or cluster analysis. Therefore, an assessment on chemical properties of rice paddy soils should be performed to consider various soil physical conditions and agronomic practices such as fertilization, cropping system, and so on. Because of the high variability of nutrient levels across Gyeongbuk Province, nutrient management based on soil fertility test is required by respective farm land unit.

• Journal of the Korean School Mathematics Society
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• v.9 no.3
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• pp.405-424
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• 2006

The purpose of this study was to develop the instruments which can measure behavior characteristics as a component of Mathematically Giftedness with in middle school period. This study prescribed the variable factors of measurement after classify the characteristics of Mathematically Giftedness through literature studies. And it produced instruments those are finally composed of 51 items through the preliminary test. The participants for the study were 424 Korean middle school students. Statistical analyses were carried out to verify the validities and reliability. Reliability(Cronbach $\alpha$) was in behavior characteristics, .95. Content validity was found to be satisfactory by internal validity evaluation on the test items. Internal validity were analyzed by BIGSTEPTS based on Rasch's 1-parameter item-response model. Construct validity was also found to be satisfactory through factor analysis which showed the four factors which the identification instruments were intended to measure such as, General mathematical mental ability, Mathematical Ability, Processing and Obtaining mathematical information Anility and Mathematical Disposition Ability. In conclusion, the instruments about behavior characteristics of Mathematically Giftedness during middle school period developed by this study are highly reliable on its reliability and validity.

• Journal of Korean Society for Atmospheric Environment
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• v.19 no.1
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• pp.33-44
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• 2003

The atmospheric concentrations of particulate polycyclic aromatic hydrocarbons (PAHs) associated with PM$_{10}$ were determined in Taegu metropolitan area. Sampling was undertaken every five days throughout one year period from 1993 to 1994 at four sites, representing a residential, a commercial, an industrial, and a sub-urban area, respectively. Benzo (e) pyrene, benzo (k) fluoranthene, and chrysene were found to be the most abundant com-pounds during the study period. The concentrations of benzo (a) pyrene, one of carcinogenic PAHs, ranged 2.0~4.8 ng/㎥ in winter and 0.5~1.5 ng/㎥ in summer season, indicating a marked seasonal variation. It was found that there were very similar patterns in the relative profiles of PM$_{10}$-bound PAH concentrations among the four sampling sites, while the absolute levels of each PAH were significantly different from each site. In addition, the patterns of summer to winter concentration ratios for each PAH were almost identical between the different sites. Despite difficulties due to the lack of good markers for specific sources in the target compounds, we were able to evaluate and describe the effects of vehicle emissions and space heatings, using relative profiles of PAHs, winter to summer (W/S) ratios, PAH-to-PAH ratios, and the result of principal component analysis. As a con-sequence, it was concluded that the vehicle emissions in urban and sub -urban areas are likely to be a major contributor for PAH loadings in the ambient atmosphere during the non-heating season, while the contributions of residential heating and local industrial oil burning emissions were highly significant in heating season.son.

• Journal of the Korean association of regional geographers
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• v.21 no.2
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• pp.394-410
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• 2015

This study aims to classify climate zones for extreme climate indices over the Republic of Korea. First, frequencies and magitudes of extreme high temperature, spatial distributions for extreme low temperature, and extreme precipitation are analysed. Frequencies of summer days in inland region show more than coastal region. In frequencies of frost days, the characteristics of altitude and longitude are appeared. Heavy precipitation days show many frequencies in the southern coastal region and Jeju island, but little in Gyeongsangbuk-do region. The classification of climate zone for extreme climate indices by principal component analysis and cluster analysis is conducted for the first half, second half of study period, and climatology period for 1981-2010. Summer days are classified according to latitude. In case of frost days, the eastern and the southern coastal region and Jeju island are classified as same region. Heavy precipitation days are classified according to longitude in south region of Gyeonggi-do and Gangwon-do. This study will help to prepare adaptation and mitigation system for climate change in wide range of fields.

• Smart Structures and Systems
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• v.12 no.3_4
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• pp.251-269
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• 2013

Measurement of deflections of certain bridges is usually hampered by corruption of the GPS signal by multipath associated with passing vehicles, resulting to unrealistically large apparent displacements. Field data from the Gorgopotamos train bridge in Greece and systematic experiments revealed that such bias is due to superimposition of two major effects, (i) changes in the geometry of satellites because of partial masking of certain satellites by the passing vehicles (this effect can be faced with solutions excluding satellites that get temporarily blocked by passing vehicles) and (ii) dynamic multipath caused from reflection of satellite signals on the passing trains, a high frequency multipath effect, different from the static multipath. Dynamic multipath seems to have rather irregular amplitude, depending on the geometry of measured satellites, but a typical pattern, mainly consisting of a baseline offset, wide base peaks correlating with the sequence of main reflective surfaces of the vehicles passing next to the antenna. In cases of limited corruption of GPS signal by dynamic multipath, corresponding to scale distortion of the short-period component of the GPS waveforms, we propose an algorithm which permits to reconstruct the waveform of bridge deflections using a weak fusion of GPS and RTS data, based on the complementary characteristics of the two instruments. By application of the proposed algorithm we managed to extract semi-static and dynamic displacements and oscillation frequencies of a historical railway bridge under train loading by using noisy GPS and RTS recordings. The combination of GPS and RTS is possible because these two sensors can be fully collocated and have complementary characteristics, with RTS and GPS focusing on the long- and short-period characteristics of the displacement, respectively.