• Korean Journal of Metals and Materials
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• v.48 no.2
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• pp.116-121
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• 2010

The Mg-Zn-RE alloy cladded with the thin Al1050 sheet was fabricated by means of a roll bonding process at $280^{\circ}C$.Microstructures and mechanical properties of the clad sheets were investigated. After heat treatment at $230^{\circ}C$ for 30 min, an Mg-rich diffusion layer with about $2{\mu}m$ in thickness was developed at the Mg and Al interface. Tensile tests were carried out in a temperature range up to $300^{\circ}C$. The clad sheet exhibits superior elongation to failure not only at room temperature but also at elevated temperatures compared with those of the Mg alloy sheet. For the deformed specimens, interface debonding does not occur and the diffusion layer shows only a few cracks.

• Journal of Ecology and Environment
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• v.29 no.6
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• pp.551-558
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• 2006

Effects of Pb and $CO_2$ on soil microbial community associated with Pinus densiflora were investigated using community level physiological profiles (CLPP) and 16S rDNA PCR-denaturing gradient gel electrophoresis (DGGE) methods. Two-years pine trees were planted in Pb-contaminated soils and uncontaminated soils, and cultivated for 3 months in the growth chamber where $CO_2$ concentration was controlled at 380 or 760 ppmv. The structure of microbial community was analyzed in 6 kinds of soil samples (CA-0M : $CO_2$ 380 ppmv + Pb 0 mg/kg + initial, CB-0M : $CO_2$ 380 ppmv + Pb 500 mg/kg + initial, CA-3M : $CO_2$ 380 ppmv + Pb 0 mg/kg + after 3 months, CB-3M : $CO_2$ 380 ppmv + Pb 500 mglkg + after 3 months, EA-3M : $CO_2$ 760 ppmv + Pb 0 mg/kg + after 3 months, EB-3M : $CO_2$ 760 ppmv + Pb 500 mg/kg + after 3 months). After 3 months, the substrate utilization in the uncontaminated soil samples (CA-3M vs EA-3M) was not significantly influenced by $CO_2$ concentrations. However, the substrate utilization in the Pb-contaminated soil samples (CB-3M vs EB-3M) was enhanced by the elevated $CO_2$ concentrations. The results of principal component analysis based on substrate utilization activities showed that the structure of microbial community structure in each soil sample was grouped by Pb-contamination. The similarities of DGGE fingerprints were 56.3 % between the uncontaminated soil samples (CA-3M vs EA-3M), and 71.4% between the Pb-contaminated soil samples (CB-3M vs. EB-3M). The similarities between the soil samples under $CO_2$ 380 ppmv (CA-3M vs CB-3M) and $CO_2$, 760 ppmv (EA-3M vs EB-3M) were 53.3% and 35.8%, respectively. These results suggested that the structure of microbial community associated with Pinus densiflora were sensitively specialized by Pb-contamination rather than $CO_2$ concentration.

• Journal of the Society of Disaster Information
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• v.11 no.1
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• pp.45-54
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• 2015

In the case of railway facilities in cities such as a railway station or a bridge, the significance of design for reducing vibration and noise is getting more significant. The vibration control solution is in need especially for an elevated railway station to block vibration of a train and secondary noise effectively. Even though a vertical vibration isolation device is able to be applied effectively to railway facilities such as elevated railway stations which transfer vibration directly from a train to a structure, the development of the vertical device is much slower than a horizontal vibration isolation device. In this paper, a vibration isolation device using wedge type friction material which is currently developing to reduce train-induced vibration effectively is introduced and test results for verification of dynamic performance is also presented. The vibration test on a concrete structure equipped with the developed vibration isolation device is conducted through which the isolation performance and dynamic properties are verified and needs for improving the performance of the device is identified.

• Korean Chemical Engineering Research
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• v.53 no.4
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• pp.407-411
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• 2015

Dense ceramic membranes have been prepared using the commercial perovsikite $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$, powders synthesized by the solid state reaction method. The as-synthesized powders were compressed into disks with 1.0 mm of thickness and the disk was sintered at $1,100^{\circ}C$ for 2 hr. The oxygen permeation flux of $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ membrane increased with the increasing temperature and oxygen partial pressure. The activation energy for oxygen permeation was increased with the increasing oxygen partial pressure. Oxygen permeation flux at $950^{\circ}C$ were measured at various flow rates of feed and sweep gas. It has been demonstrated that oxygen permeability increased at elevated flow rates of both gases, but the sweep gas is more influential.

• The Journal of Internal Korean Medicine
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• v.30 no.2
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• pp.375-387
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• 2009

Objective : Gyehyuldeung (GHD) has been widely used in oriental medicine for the treatments of cardiovascular and neurological disorders. Thus, its potential facilitatory activity on axonal regeneration was investigated in the rats. Methods: Sprague-Dawley rats were given crush injury at the sciatic nerve and the changes of axon growth after nerve injury on each nerve injury model were investigated with anti-NF-200 antibody, DiI, GAP-43 protein and Cdc2 protein Results : GHD-mediated enhancement of axonal regeneration after crush injury was measured in both qualitative and quantitative ways by immunofluorescence staining with anti-NF-200 antibody and retrograde tracing of fluorescence dye DiI. GAP-43 protein levels were elevated by GHD treatments in the distal injured sciatic nerve and DRG sensory neurons. The neurite outgrowth of DRG sensory neurons was facilitated by GHD treatment when co-cultured with Schwann cells and astrocytes prepared from injured sciatic nerves and injured spinal cord tissues, respectively. It was observed that Cdc2 protein was up-regulated in co-cultured Schwann cells or astrocytes and Cdc2 protein signals were co-localized to a certain extent with those of phospho-vimentin protein. Conclusions : These results suggest that GHD may play a facilitatory role in axonal regeneration by acting on the injured axons and adjacent non-neuronal cells. The current findings may be useful for the development of therapeutic targets through more specific explorations on molecular interactions between herbal components and endogenous factors.

• International Journal of Contents
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• v.16 no.2
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• pp.30-40
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• 2020

This study performed GIS and statistical analyses on the location and spatial characteristics of the slum in Daejeon. Spatial data of 648 slum residents in Daejeon were collected and 131 residents among them were surveyed. The results showed the trends of higher rent, lower social exclusion and closer neighboring relations in slum center than the surrounding areas, which could be interpreted as the interrelated multilateral effects of the micro- (housing), meso- (relations), exo- (community) and macro- (government policy) systems. The strong bonds among neighbors and various supports from social service facilities elevated the slum area's rent and diminished residents' social exclusion more than housing conditions (for instance, poor hygiene and low safety). Slum tenants willingly paid a premium for their substandard housings and refused moving to governmentally provided modern housing units. In urban development, administrative authorities need to be cautious about slum uprooting. Much rather an alternative renewal approach is needed which protects the slum's intimate relations while improving its overall living standards.

• Journal of Nutrition and Health
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• v.31 no.2
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• pp.135-142
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• 1998

This study was undertaken to determine whether dehulled defatted flour has an effect on postprandial plasma lipoprotein composition, hepatic lipid composition, enzyme and hormone levels in rats. Control(casein) and experimental (dehulled defatted soy flour)diets were fed to rats for 7 weeks. all animals (S. D. rats, male) were sacrificed 2 hrs after the feeding of 5g of each diet. Defatted soy flour feeding significantly lowered postprandial plasma total cholesterol, chylomicron/VLDL-cholesterol, hepatic cholesterol and triglyceride(TG) as compared with casein feeding, whereas no significant effect on plasma TG was observed. Intestinal kipase activity was elevated , whereas trypsin activity was suppressed in the dehulled defatted soy flour group. Plasma glucagon, thyroid hormone and hepatic HMG-coA reductase levels were not affected by diet treatment. These results hypothesize that dehulled defatted soy flour affects cholesterol digestion and absorption in guts, thus delaying the appearance of chylomicron cholesterol in plasma or affecting the disappearance of chylomicron remnant to high-density-lipoprotein(HDL).

• Journal of the Korean Ceramic Society
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• v.32 no.10
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• pp.1139-1146
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• 1995

$\beta$-SiC whiskers could be formed from a system of mullite-carbon-hydrogen by VLS mechanism at elevated temperatures. It was considered that methane gases were generated from the reaction of hydrogen gases with carbon black, and were reacted with mullite to produce two kinds of gases; silicon suboxide (SiO) and carbon monoxide (CO) of precursors of SiC. With increasing the synthesizing temperature up to 146$0^{\circ}C$, the formation of $\beta$-SiC whisker increased from 0.58 mg/$\textrm{cm}^2$ to 3.98 mg/$\textrm{cm}^2$ on the basis of unit area of carbon block, and the diameters of whiskers had their uniformity due to the reduction in stacking faults.

• The Korean Journal of Mycology
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• v.37 no.1
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• pp.60-64
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• 2009

Effects of $CO_2$ concentration (500, 800, 1,000 and 1,500 ppm) on the initiation and development of fruit body of Grifola frondosa on sawdust cultivation were studied. Optimum concentrations of carbon dioxide for the initiation and development of the fruit body showed the ranges from 500 to 800 ppm. Fruit body initiation was accelerated at lower than 800 ppm $CO_2$ exposure but the maturing of the fruit body was not influenced by above treated $CO_2$ concentrations. The higher ratio of primordial formation, faster fruit body initiation and higher yield were obtained at below 800 ppm of $CO_2$ level, whereas over 1,000 ppm of $CO_2$ levels showed abnormal and lower quality of fruiting bodies. Based on the above results, it is concluded that the favorable $CO_2$ level for bag culture of G. frondosa was below 800 ppm.

• Korean Journal of Agricultural and Forest Meteorology
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• v.24 no.4
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• pp.275-284
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• 2022

Changes in air temperature, CO₂ concentration and precipitation due to climate change are expected to have a significant impact on soybean productivity. This study was conducted to evaluate the climate change impact on growth and development of determinate soybean cultivar in the southern parts of Korea. The high temperature during vegetative period, which does not accompany the increase of CO₂ concentration, increased the canopy photosynthetic rate in soybean, but after flowering, the high temperature above the optimal ranges interrupts the photosynthetic metabolism. In yield and yield components, high temperature reduced both the pod and seed number and single seed weight, resulting in a reduction of total seed yield. On the other hand, the increase in CO₂ concentration dramatically increased the canopy photosynthetic rate over the whole growth period. In addition, high CO₂ concentration increased the number of pods and seeds, which had a positive effect on total seed yield. Under concurrent elevation of air temperature and CO₂ concentration, canopy photosynthesis increased significantly, but enhanced canopy photosynthesis did not lead to an increase in soybean seed yield. The increase in biomass and branch by enhanced canopy photosynthesis seems to be attributed to an increase in the total number of pods and seeds per plant, which compensates for the negative effects of high temperature on pod development. However, Single seed weight tended to decrease rapidly by high temperature, regardless of CO₂ concentration level. Elevated CO₂ concentration did not compensate for the poor distribution of assimilations from source to sink caused by high temperature. These results show that the damage of future soybean yield and quality is closely related to high temperature stress during seed filling period.