• Economic Analysis
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• v.25 no.1
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• pp.34-65
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• 2019

This paper investigates the effects on Korean exports of demand in developed economies, and how these effects have changed since the global financial crisis. As a measure of import demand, we use import intensity-adjusted demand to take into account heterogenous import intensities across components of aggregate demand. Our estimation of a dynamic panel regression model reveals that Korea's exports to the G7 countries were elastic with respect to the import demand of these countries until the global financial crisis, but have shifted to become inelastic since. Furthermore, we separately estimate the effects of the different components of the G7 countries' aggregate demand (private consumption, public consumption, investment and exports). The results show that the decrease in private consumption in the G7 countries during the crisis had a significant impact in causing the decline in Korea's exports to them, but that the increase in their public consumption since the crisis has had a significant effect on driving increased Korean exports to them. The effects of the G7 countries' exports on Korea's exports to them remain positive and significant during both the pre- and post-crisis periods. The effects of the G7 countries' investments on Korea's exports are also positive and significant, but the positive effect has weakened since the crisis. Our findings suggest that the overall effect of changes in the G7 countries' import demand on Korea's exports to them has weakened compared to the pre-crisis period.

• Journal of the Korean Dietetic Association
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• v.23 no.3
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• pp.285-299
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• 2017

This study was conducted to compare the perception and fast food usage patterns of adults classified by age in Busan. The survey was conducted from April 15 to June 15, 2017 by questionnaires and the data were analyzed using SPSS 24.0 Overall, 74.1%, 58.1%, 40.7%, 20.3%, 29.7% and 17.9% of individuals in their 20s, 30s, 40s, 50s, 60s and 70s, respectively, consumed fast foods more than once a week. Additionally, 66.0%, 52.5%, 25.7%, 16.0%, 22.9% and 11.7% of individuals in their 20s, 30s, 40s, 50s, 60s, and 70s, respectively, preferred fast foods. There was a significant difference in the basis for choosing menu among the groups, with 'preference' and 'price' being most important to those in their 20s and 30s, on the other hand 'preference' and 'companion' being most important to members of other age groups. As their age increased, individuals spent less money on fast food. Overall, 81.5%, 59.9%, 50.0%, 40.1%, 46.3%, and 28.4% of individuals in their 20s, 30s, 40s, 50s, 60s and 70s thought that fast food was a suitable substitute for a meal. Age affected the substitutability of fast food for a meal (P<0.001). Additionally, the ratio of individuals in their 20s and 30s that skipped breakfast was higher than in other age groups. In addition, age showed a significant positive correlation with obesity and dietary attitude, whereas it showed a negative correlation with nutrition knowledge, use frequency, perception degree and preference. Nutrition knowledge and dietary attitude showed no relationship with preference. These results imply that a nutrition education program should be developed and conducted to induce subjects to manage their dietary habit and develop healthier dietary patterns.

• Bulletin of the Korean Chemical Society
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• v.27 no.7
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• pp.1038-1042
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• 2006

A new type of DTPA-bis-amides (L1-L4) and their Gd(III)-complexes of the type $[Gd(L)(H_2O)]{\cdot}nH_2O$ (5: L1; 6: L2; 7: L3; 8: L4) have been prepared and characterized by analytical and spectroscopic techniques. The X-ray crystal structure of 8 has been determined for structural confirmation. The coordination geometry adopts a tricapped trigonal prism geometry with L4 acting as a chelate octadentate and a water molecule in the coordination sphere. Crystals are monoclinic, $P2_1$, a = 14.468(3), b = 19.235(4), c = 13.527(2) $\AA$ $\beta$ = $107.245(3)^{\circ}$, V = 3595.2(11) $\AA^3$, Z = 4, $D_{calc}$ = 1.570. Significant increases in relaxivities are observed with 6 and 7 as compared with that of $Omniscan^{(R)}$, a commercial MR agent: R1 = 12.46 $mM^{-1}\;s^{-1}$, R2 = 8.76 $mM^{-1}\;s^{-1}$ for 6; R1 = 12.77 nm-1 s-1, R2 = 7.60 mM-1 s-1 for 7; R1 = 4.9 $mM^{-1}\;s^{-1}$, R2 = 4.8 $mm^{-1}\;s^{-1}$ for $Omniscan^{(R)}$. In the case of 5, however, both R1 and R2 are found to be lower to show 2.09 $mM^{-1}\;s^{-1}$, and 1.82 $mM^{-1}\;s^{-1}$, respectively.

• Food Science and Preservation
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• v.5 no.3
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• pp.286-291
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• 1998

The sensitivity of various pathogenic bacteria(Escherichia coli O157:H7, Listeria monocytogenes, Staphylococcus aureus 196E, Salmonella typhimurium) to the water extract of green tea was tested. Tryptic soy broth was inoculated with 10$\^$5/CPU/ml of pathogenic bacteria and incubated at 35$^{\circ}C$ for 30 hours. The extract was added at a final concentration of 0-2%(w/v) into culture broth at the mid or late exponential phase of bacteria. The growth of pathogenic bacteria was inhibited with increasing concentrations of the extract in culture broth and the late exponential phase cells were more resistant than the mid exponential phase cells. Cram positive bacteria(L. monocytogenes and S. aureus 196E) were more sensitive than Cram negative bacteria(E. coli O157:H7 and S. typhimurium). S. aureus had the highest sensitivity, followed by L monocytogenes, E. coli O157:H7. S. typhimurium was the most resistant to the water extract of green tea.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.2
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• pp.10-18
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• 2010

Scramjet engine is one of the core parts of hypersonic vehicle of next generation and being investigated by many countries. Korea Aerospace Research Institute performed a ground test of the model scramjet engine S1 in 2007. And, S2 model which is improved from S1 model in engine startability and thrust was tested with HIEST (High Enthalpy Shock Tunnel) at Kakuda Space Center of JAXA. Design condition of S2 model was Mach 6.7, however, it was tested at Mach 7.7 as an off-design condition test. As a test result, flow separation was found at the inside of the intake, but the engine showed stable combustion pressure distribution. Furthermore, compared to other test models, S2 model showed a good performance value in thrust and specific impulse.

• Journal of Wetlands Research
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• v.21 no.4
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• pp.298-304
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• 2019

In this paper, the analytical method to derive wind fragility for urban street tree in Korea was shown. Monte Carlo Simulation method was used to determine the probability of failure for urban street tree. This probability result was used to determine wind fragility parameters for four types of tree based on the study of street tree species in urban area in Daegu, Korea. Wind fragility for street tree was presented in terms of median capacity and standard deviation of the natural logarithm of the capacity. Results showed that the dominant factor affecting the probability of failure of tree under wind load was their diameter. Moreover, amongst the four types of tree chosen, the tree with height 7m and diameter 35cm had the lowest probability of failure under wind loading, whereas the tree with height 8m and diameter 30cm could resist the least wind loading. The median failure wind speed for urban street tree with height 7m were 43.8m/s and 50.6m/s for diameter 30cm and 35cm, respectively. Also, for tree with height 8m, their median failure wind speeds were 38.7m/s and 45.4m/s for tree with diameter 30cm and 35cm, respectively.

• Journal of Bio-Environment Control
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• v.22 no.2
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• pp.116-122
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• 2013

We investigated characteristics and self-incompatibility genotypes of 11 crabapple cultivars to introduce a new pollinizer of 'Fuji' apple tree in Korea. Flowering dates of eleven crabapples were two to seven days earlier than that of 'Fuji'. The rate of pollen germination in vitro was ranged from 85.6% to 98.0% except 'Virginia'. Controlled pollination treatment with each crabapples to 'Fuji' increased fruit set rate about 20.4% to 34.4%, the number of seed per fruit about 13.8% to 42.3% and fruit weight about 7.4% to 16.7% compared to open pollination. Tested crabapples were resistant to peach fruit moth, brown leaf spot and sooty blotch in general. A PCR amplification method using S-RNase primers was carry out in eleven crabapples. S-alleles, $S_3$, $S_5$, $S_9$, $S_{10}$, $S_{20}$, $S_{26} from six crabapples were determinated. Through sequencing analysis, $S_5$ ('Manchurian', 'Virginia') and $S_9$ ('Yantaishagou') showed 100% homologous to previous result. Based on our results, it was recommended that 'Manchurian', 'Hopa A', 'Hanyaehanakaidou', 'Spectabilis' could be promising pollinzers for 'Fuji' apple cultivar.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.724-727
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• 2002

2,7-dibromo-9, 9-dialkyl-substituted-fluorene derivatives were prepared by the alkylation of 2,7-dibromofluorene with various alkyl groups under two-phase phase transfer catalysis (PTC) conditions, as monomers for synthesizing poly(dialkylfluorene)s. Tetra-nbutylammonium hydrogen sulfate (TBAHS) was used as a phase transfer catalyst to enhance nucleophilic substitution. In addition, NaOH in water (25M) was used as a base to generate anions. Compared to conventional alkylation using butyllithium(BuLi), the reaction using the PTC technique attained high selectivity and substantial conversion of reactants, due to the enhanced reaction rate, while the reaction was carried out under moderate conditions. An approximately 90% yield was obtained from the reaction and the reaction time was remarkably reduced. 2,7-dibromo-9,9-dihexyl-fluorene, 2,7-dibromo-9,9-dioctyl-fluorene, and 2,7-dibromo-9,9-di(2-ethylhexyl)-fluorene were effectively synthesized by phase transfer catalytic reaction.

• Environmental Analysis Health and Toxicology
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• v.22 no.3
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• pp.219-225
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• 2007

A series of new derivatives of 1-(5-oxohexyl)-3,7-dimethylxanthine has been prepared for the treatment of the vascular dementia. To investigate hepatoprotective effect of these derivatives, the serum biochemical activity and the histological change of liver tissue were evaluated in carbon tetrachloride ($CCl_4$) treated rats. The activities of aspartate aminotransferase and alanine aminotransferase and the activities of total cholesterol, triglyceride and total bilirubin in 5-oxohexyl-3,7-dimethylxanthine derivatives pretreated rats were significantly decreased compared to the $CCl_4$ only treated rats but the content of glutathione S-transferase was increased compared to the $CCl_4$ only treated rats. These results indicated that 5-oxohexyl-3,7-dimethylxanthine derivatives have hepatoprotective effect in $CCl_4$ intoxicated rats.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.04a
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• pp.245-245
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• 1994

From the active fraction, cytotoxic constituents 1-5 were isolated and identified to be 2(S)-5,7-dihydroxy-8,2'-dimethoxyflavanone (1), wogonin (5,7-dihydroxy-8-methoxyflavone, 2), 5,7-dihydruxy-8,2'-dimethoxyflavone (3), 2(5) -5,7,2'-trihydroxy-8-methoxyflavanone (4), 2(S) - 5,2',5'-trihydroxy-7,8-dimethoxyflavanone (5), respectively, with those of specimens$\^$1-2)/