• Carbon letters
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• v.1 no.3_4
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• pp.158-164
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• 2001

It is well known that the fabrication process of carbon/carbon composites is very complex. Above all, the carbonization process have major effect on the morphology development of carbon matrix. Carbon/carbon composites of 4-directional fiber preform were fabricated using the coal tar based pitch as a matrix precursor in this study. According to carbonization pressure of 1 bar, 100 bar, 600 bar, and 900 bar, morphological changes of cokes and matrix of composites were discussed. As the carbonization pressure increased to 600 bar, the flow pattern morphology of bulk mesophse was well developed. On the contrary, mosaic pattern morphology was found in case of 900 bar of carbonization pressure. It is confirmed that the carbonization pressure have profound effect on the degree of graphitization and crystal size of carbon matrix. Even in the highly densified carbon/carbon composites, large voids were still found in the matrix pocket region.

• Journal of Integrative Natural Science
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• v.16 no.2
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• pp.69-74
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• 2023

In Dictyostelium , there are 15 Ras subfamilies, including 11 Ras, 3 Rap, 1 Rheb. The Ras proteins are involved in regulating various cell processes as switch proteins. The functions of many Ras proteins have been identified, but some of Ras proteins have not yet been identified. Here, we focused on identifying the roles of RasW among them. To investigate the functions of RasW in cell morphology, cell migration, and development in Dictyostelium , we compared the phenotypes of wild-type cells and rasW null cells. rasW null cells showed a larger, more spread-out morphology and reduced cell motility compared to wild-type cells. There was no significant difference between wild-type cells and rasW null cells during multicellular developmental process. These results suggest that RasW is involved in regulating cell morphology and cell migration in Dictyostelium.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.150-150
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• 2022

Plant reproduction associated with crop yields is highly vulnerable to global climate change components such as high and cold temperatures. The objectives of this study were to determine the effects of season-high exposure to temperature treatments in pollen morphology on Adzuki bean (V. angularis) and Mung bean (V. radiate). V. angularis and V. radiata were treated at high temperatures in the high temperature gradient greenhouse designed to cause temperature deviation. The pollen shapes treated at high temperature were compared by an electron scanning microscope. As a result, it was confirmed that the number of abnormal pollens morphology at high temperature was the least in V. radiata, and V. angularis was vulnerable to high temperatures. Also, it was found that the number of abnormal pollen morphology atT4 (Con +5~6℃) varied according to the cultivars of V. angularis. Therefore, the differences in Vigna species or cultivars with thermo-tolerance in pollen morphology to high temperature are projected to occur in the changeable future climate.

• Korean Journal of Agricultural Science
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• v.48 no.3
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• pp.447-454
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• 2021

This study was conducted to evaluate the effects of different copper sources (inorganic and organic) on the growth performance, fecal copper excretion, intestinal morphology, and health in growing pigs. A total of 40 growing pigs (30.22 ± 1.92 kg) were randomly assigned to 5 dietary treatments: a basal control diet (CON), 4 experimental diets supplemented with either copper sulfate (CuSO₄), Cu-glycine complex (CuGly), Cu-amino acid complex (CuAA), or Cu-hydroxy-4-methylthio butanoate chelate complex (CuHMB) at 100 ppm, respectively. At the end of the study (28 days), fecal and blood samples were collected, and the pigs were slaughtered to determine the intestinal morphology. During the 28 days of the experimental period, pigs fed the inorganic and organic copper showed a higher average daily gain (p < 0.01) and gain feed ratio (p < 0.01). There were no differences in mineral concentrations of the serum; however, the copper concentration of the feces was lower (p < 0.01) in the CuAA and CuHMB groups. The intestinal morphology and blood profiles did not significantly differ between the groups. In conclusion, the organic copper sources (CuAA and CuHMB) can be used as a growth promoter to replace the CuSO₄ without any negative effects on health in growing pigs and to reduce fecal copper excretion.

• KIEAE Journal
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• v.14 no.2
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• pp.47-59
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• 2014

In the present circumstance of exploring measures for sustainable development, finding and using planning elements of historical city is getting important as a urban planning tool. Thus this study aims to examine the characters of Korean traditional urban form through three periods, Josun, modern and contemporary eras. Three urban centers representing different characteristics were selected; historical center based on 14th century's traditional planning, modern period urban center, which is related with development of railway, and contemporary urban center of late 20th century. Analyse of urban tissue, composed with form and scale of street network, blocks and plots, shows that each urban center of Seoul has certain common attributes in terms of morphology in spite of the difference of formation and development period. However this historical urban forms are rarely applicated in the current urban planning, such as new-town planning or district unit plan. This shows the necessity of modification of urban regulation for preserving the identity of our city and pursuing sustainable development.

• Journal of Embryo Transfer
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• v.31 no.2
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• pp.109-116
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• 2016

The recovery of epididymal sperm in animals is considered as one of the important tools to preserve high value or endangered species. However, there are no appropriate castrating indicators such as months of age in bull, sperm morphology, and motility, particularly in young Korean native bull (Hanwoo). Therefore, this study aimed to investigate sperm number, morphology, and motility of sperm in the epididymis tail of young Hanwoo bulls at 8 and 15 months of age. After castration, epididymal tails were collected and minced with blades to recover sperm. In experiments 1 and 2, sperm number, morphology, and motility were examined. Total number of sperm and percentage of normal sperm from bulls at 8 months of age was lower than that of bulls at 15 months of age after collection (P<0.05). Percentage of abnormal head, tail, proximal cytoplasmic droplet, dead and damaged acrosome of sperm from bulls at 8 months of age were higher than those of bulls at 15 months of age (P<0.05). In experiment 3, sperm motility from bulls at 8 and 15 months of age were examined before freezing and after thawing. Frozen-thawed sperm at 8 months of age showed low total motility and motile sperm with ${\geq}25{\mu}m/sec$ compared to those at 15 months of age and commercially-used sperm (P<0.05). In conclusion, sperm derived from the epididymal tail of bulls at 8 months of age showed high abnormal morphology and poor motility, which are not adequate for AI and IVF. On the other hand, sperm derived from the epididymal tail of bulls at 15 months of age showed high normal morphology and motility.

• Journal of the Korean Ceramic Society
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• v.44 no.3 s.298
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• pp.133-136
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• 2007

The crystal morphology of hydroxyapatite [HAp] phase in gelatin [GEL] matrices was investigated with the condition of a GEL precursor treatment in an aqueous solution of $H_{3}PO_{4}$ at $37-80^{\circ}C$. Needle-shaped nanocomposite particles were prepared through a dynamic reaction during a coprecipitation process using a phosphoric GEL solution. Various types of mineralized morphology appeared with a phosphorylated condition of the GEL solution. HAp/GEL nanocomposite slurries showed the existence of an octacalcium phosphate [OCP] phase during the process.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.153-156
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• 2000

• Applied Microscopy
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• v.44 no.2
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• pp.41-46
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• 2014

In this study, the vegetative and reproductive morphology and anatomy of two Hawaiian endemic Portulaca species were examined. Specifically, P. molokiniensis and P. sclerocarpa were compared to closely related species in the genus. The comparisons were both qualitative and quantitative, using characteristics of leaves, stems, roots, and fruits. Tissue organizations of vegetative and reproductive parts of the plants were assessed using microtechnique procedures, statistical analysis, and scanning electron microscopy. The most notable features of these two species were (1) the size and frequency of stomata in P. molokiniensis, and (2) the large number of sclerenchymatous cell layers in the thickest fruit walls of P. sclerocarpa. These findings may imply that stomata development in P. molokiniensis and thick fruit wall development in P. sclerocarpa are evolved features of survival. In particular, the development of thickened walls in indehiscent fruits likely has evolutionary implications of ecological tolerance for better adaptation.

• Polymer(Korea)
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• v.30 no.1
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• pp.50-55
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• 2006

When the monodisperse polystyrene(PS)/HDDA polymer particles were synthesized via one-step polymerization using polystyrene seed particles by dispersion polymerization, the effects of 1) the molecular weight of seed polymer particles, 2) the ratio of the absorbed HDDA to the seed polymer particles (swelling ratio) and 3) seeded polymerization rate on the surface morphology of PS/HDDA polymer particles were investigated. It was observed that the creation of the crater shaped defect on the surface of PS/HDDA polymer particles was irrespective of the molecular weight of seed polymer ant swelling ratio. But its surface morphology could be controlled by the change of the seeded polymerization rate.