• Proceedings of the Korea Concrete Institute Conference
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• 1999.10a
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• pp.671-674
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• 1999

With increasing content of granulated blase furnace slag in cement, the content of capillary pores in the mortar decreases and later age strength of the concrete. Therefore, this provides greater reserves study is carried out to estimate frost resistance of high-strength concrete specimens with water cement ratios using blast-furnace slag. 1. Blast furnace concrete is comparatively more good frost resistance than normal concrete. 2. As the blast furnace slag increases, the quantity of pores with a radius of more than 30nanometer decreses.

• Carbon letters
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• v.7 no.2
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• pp.114-118
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• 2006

Isotropic pitch-based carbon fiber has been activated by steam diluted in nitrogen in order to characterize the microporosity. Especially, 40 wt% burn-off ACFs were prepared from different conditions to compare the pore structure and size. The ACFs were thinly sliced to investigate the inside pores by TEM and image analyzer. As expected, the adsorption characteristics of these ACFs were quite different from one another because of different pore structure and size. Most pores are not slit-shaped but rather round. Small round micropores become broad and irregular as increasing the activation time and temperature.

• Proceedings of the KIEE Conference
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• 2008.05a
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• pp.201-202
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• 2008

Formation of pores in melt processed ceramics oxides and its effect on the microstructure were studied. Spherical Pores with a size of a few tens of microns were formed due to the evolution of oxygen gas during melting of a oxide. The liquid pockets were converted into sperical oxide regions with a lower oxide density through the peritectic reaction during subsequent fabrication.

• Journal of the Korean Ceramic Society
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• v.41 no.7
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• pp.555-559
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• 2004

Ceramic foams were prepared by a self-blowing process of a polysiloxane with A1$_2$O$_3$ as a filler. The release of water and ethanol vapor during the condensation reaction of the polymer triggered the pores in the polymer melt. The size. interconnectivity and shape of the pores in the ceramic foams were strongly dependent on the viscosity of the polymer melt, which could be varied by the content and size oi the filler. When the content of the filler inceased and the size of the filler decreased. the size of the pores were decreased and the thickness between the pores were increased. In the addition, the viscosity of polymer melt increased by the pretreatment at 130$^{\circ}C$ for Ire intermolecular cross linking thereby stabilizing the foam structure. The density and compressive strength of the ceramic foams were affected by the heating rate during the blowing process.

• Journal of the Korea Institute of Building Construction
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• v.19 no.1
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• pp.59-66
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• 2019

In this study, the effects of blast furnance slag cement and frost-resistant accelerator on shrinkage properties and shrinkage properties of mortar were examined. As a result, the addition of the frost-resistant accelerator to both OPC and BB has a small effect on the flash properties of mortar and the compressive strength increases from the early ages. In addition, when a frost-resistant accelerator is used in excess of the standard usage amount, it is necessary to examine the relationship of the expansion behavior at the early age, especially, between the compressive strength development and the expansion property. And it was confirmed that the addition of the frost-resistant accelerator tended to increase the shrinkage of mortar using the OPC and BB. With the addition of the frost-resistant accelerator, the amount of pores with a diameter of under the 30nm, especially, the amount of pores with a diameter of 20 to 30nm and the amount of pores with an ink-bottle decrease, and the shrinkage increases. And it is considered that a change in the amount this range of pores has a large effect on the shrinkage property.

• Animal cells and systems
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• v.11 no.2
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• pp.141-146
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• 2007

Cantharidin is produced by blister beetles (Coleoptera: Meloidae) and smaller oedemerid beetles (Coleopetra: Oedemeridae) and is found in hemolymph and various tissues. The function of cantharidin in the courtship behaviour of meloids had never been fully established. Our studies show a correlation between density of cuticular pores and cantharidin titre of the scape and pedicel segments of male specimens of the East African species of Epicauta nyassensis (Haag-Rutenberg, 1880) (Coleoptera: Meloidae). Light microscopy of semi-thin cross sections of the male scape and pedicel indicates that there are many canal shaped structures that stretch from the antennal hemolymph to the antennomere surface. These structures may be tubules, which transport cantharidin circulating in the hemolymph to the surface, where the compound can be released via cuticular pore openings. Analyses of the head capsule and antennal segments of E. nyassensis females which had been copulated with males revealed low titre of cantharidin in the first two antennal segments. The density of the scape and pedicel pores of females was to some extent higher than the density of these pores on flagellum; however it was considerably lower than that of the males. Interestingly, no tubular cell or other transport structures were found in the cross sectioning of the female antennomeres or on the integument surface. During mating, male antennomeres, as well as cantharidin containing pores which are located on the $1^{st}\;and\;2^{nd}$ antennomeres, come into direct contact with the female antennae and may release cantharidin to their surface. Female E. nyassensis may be able to discriminate the opposite sex with abundant reserves of cantharidin prior to mating. This is another evidence that cantharidin function in close range sexual selection.

• Korean Journal of Materials Research
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• v.23 no.6
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• pp.339-343
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• 2013

Porous Ti-systems with unidirectionally aligned channels were synthesized by freeze-drying and a heat treatment process. $TiH_2$ powder and camphene were used as the source materials of Ti and sublimable vehicles, respectively. Camphene slurries with $TiH_2$ content of 10 and 15 vol% were prepared by milling at $50^{\circ}C$ with a small amount of oligomeric polyester dispersant. Freezing of the slurry was done in a Teflon cylinder attached to a copper bottom plate cooled at $-25^{\circ}C$ while unidirectionally controlling the growth direction of the camphene. Pores were generated subsequently by sublimation of the camphene during drying in air for 48 h. The green body was heat-treated at $1100^{\circ}C$ for 1 h in a nitrogen and air atmosphere. XRD analysis revealed that the samples composed of TiN and $TiO_2$ phase were dependent on the heat-treatment atmosphere. The sintered samples showed large pores of about 120 mm which were aligned parallel to the camphene growth direction. The internal wall of the large pores had relatively small pores with a dendritic structure due to the growth of camphene dendrite depending on the degree of nucleation and powder rearrangement in the slurry. These results suggest that a porous body with an appropriate microstructure can be successfully fabricated by freeze-drying and a controlled sintering process of a camphene/$TiH_2$ slurry.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.2
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• pp.53-59
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• 2017

In this experimental study, the characteristic of damages on GFRP rebar exposed to high temperature only and immerged in alkaline solution after the exposure to high temperature was analyzed through microscopic image analysis. The found microcrack and pores in resin matrix were quantitatively compared if there was effect of pre-exposure to high temperature. The damages, such as microcrack and pores in resin matrix, by alkali exposure were mainly found in rebar surface. On the other hand, the pores caused by high temperatures were extensively found in a section and had greater width than those caused by the alkali exposure. In results of the quantitative comparison, the accumulated length and widths of microcrack and pores in resin matrix in pre-exposed GFRP rebar to high temperature were respectively 1.5 and 1.4 times of those in the GFRP rebar only immerged in alkali solution. Therefore, the deterioration of resin matrix by the alkali exposure could be accelerated due to the pre-exposure to high temperature.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1162-1168
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• 2015

Accelerated thermal aging of chlorosulfonated polyethylene (CSPE) was performed for 0 days, 80.82 days, and 161.63 days at 100℃, which is equivalent to 0 y, 40 y, and 80 y of aging, respectively, at 50℃. After freshwater flooding, the volume electrical resistivity of CSPE was highest after 180 days of drying, and its insulating property recovered when dried for more than 300 days. The dielectric constant of the CSPE was not measured after seawater flooding. The dielectric constant of the accelerated thermally aged CSPE was higher after freshwater flooding than that before seawater flooding. The bright, open pores of CSPE were converted into dark, closed pores after seawater flooding, and the dark, closed pores of the accelerated thermally aged CSPE samples were partly converted into bright, open pores after freshwater flooding. The apparent density of CSPE increased slightly whereas its elongation at break (EAB) decreased until 80 y of accelerated thermal aging before seawater flooding. The peak binding energies of oxygen in the non-accelerated and accelerated thermally aged CSPE for 40 y and 80 y were shifted by more than 1.0 eV after seawater and freshwater flooding. The CH2 content in the non-accelerated and accelerated thermally aged CSPE for 40 y and 80 y after seawater flooding for 5 days was lower than that before seawater flooding whereas atoms such as Cl, O, Pb, Al, Si, Sb, and S that are related to conducting ions such as Na⁺, Cl^-, Mg²⁺, SO4 ^2-, and K⁺ were relatively increased.

• Korean Chemical Engineering Research
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• v.57 no.2
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• pp.267-273
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• 2019

Hierarchically porous $Fe_2O_3$ nanofibers with meso- and macro- pores are designed and synthesized by electrospinning and subsequent heat-treatment. The macro pores are generated by selectively decomposition of polystyrene as a dispersed phase in the as-spun fibers containing $Fe(acac)_3$/polyacrylonitrile continuous phases during heat-treatment. Additionally, meso-pores formed by evaporation of infiltrated water vapor during electrospinning process interconnected the macro-pores and results in the formation of hierarchically porous $Fe_2O_3$ nanofibers. The initial discharge capacity and Coulombic efficiency of the hierarchically porous $Fe_2O_3$ nanofibers at a current density of $1.0A\;g^{-1}$ are $1190mA\;h\;g^{-1}$ and 79.2%. Additionally, the discharge capacity of the nanofibers is $792mA\;h\;g^{-1}$ after 1,000 cycles. The high structural stability and morphological benefits of the hierarchically porous $Fe_2O_3$ nanofibers resulted in superior lithium ion storage performance.