• Proceedings of the Korean Institute of Building Construction Conference
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• 2016.10a
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• pp.32-33
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• 2016

This purpose of this study is to find the properties of pore structure and length change of blast furnace slag cement added alkali powder stimulant on shrinkage reducing agent presence. In length change, the specimen added alkaline stimulant was smaller than normal blast furnace slag concrete. And the specimen added shrinkage reduction agent was confirmed to show smaller rate of length change than the length. In MIP analysis of 1day-age, 0.1㎛ subsequent pore amount of the specimen added alkaline stimulant was significantly smaller value the normal blast furnace slag concrete specimen.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.4
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• pp.126-136
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• 2003

The B value on the saturated soil is commonly known as the amount of 1. Usually this concept is consistent with the condition that effective stress is equal to zero, but it was reported in some literatures that the B value was less than 1 in spite of saturated condition in the test of very stiff material such as rock and quasi-stiff material on which the stiffness can be mobilized because of effective stress not equal to zero. In this study the B value was measured on various effective stress conditions on normally consolidated clay. The test results in the B value less than 1 in spite of perfect saturation. The measured excessive pore water pressure was not only smaller than the change of the total stress, but also the function of time on clay.

• Journal of Powder Materials
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• v.19 no.4
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• pp.304-309
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• 2012

The purpose of our study was to develop the fabrication method of porous diatomite ceramics with a porosity gradient by centrifugal molding. The processing variables of centrifugal molding were derived from Stoke's law of sedimentation, which were the radius of the particles, the acceleration due to centrifugal molding and the dynamic viscosity of the slurry. And these could be controlled by ball-milling conditions, centrifugal conditions, and the addition of methyl cellulose, respectively. The effects of processing conditions on the gradient pore structure of diatomite were investigated by particle size analysis, scanning electron microscope, and mercury porosimeter.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2005.10a
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• pp.361-366
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• 2005

Since most soils exist above the ground water table, negative pore pressure exist in unsaturated soils. Negative pore water pressure in unsaturated soil affects the soil structure and degree of saturation and it is important for accurate evaluation of unsaturate flow and behavior. This negative pore pressure is called a matric suction which causes an increased shear strength. Therefore, it is required that the effect of increase in the shear strength should be included in a geotechnical analysis. From the test result, the influence of net confining pressure and matric suction on the shear strength was analyzed and strength parameter was increased with matric suction increase and a unliner relationship was found to relate matric suction and shear strength.

• Applied Chemistry for Engineering
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• v.2 no.2
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• pp.147-154
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• 1991

Thermogravimetric measurements have been carried out to investigate the stabilization and carbonization of copolymer of acrylonitrile(95 wt %) and methyl acrylate(5 wt %) at various heating rates. The cyclization and dehydrogenation during the stabilization were important factors to determine pore development in the carbonization process. The pore and the specific surface area during the carbonization began to develope at the temperature higher than $400^{\circ}C$.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.186-190
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• 2011

Periodically ordered mesoporous manganese oxides were synthesized in a single and double replication procedure. Mesoporous SBA-15 and -16 silica and their reverse replica carbons were successively used as hard templates. The silica and carbon pore systems were infiltrated with $Mn(NO_3)_2{\cdot}xH_2O$ or $Mn(AcAc)_2$, which was then converted to $Mn_2O_3$ at 873 K; the silica and carbon matrix were finally removed by NaOH solution or calcinations in air. The structure of the mesoporous $Mn_2O_3$, using a carbon template, corresponds to that of the original SBA-15 and SBA-16 silica. The products consist of hexagonally arranged cylindrical mesopores with crystalline pore walls or cubic mesoporous pores. The structure of replica has been confirmed by XRD, TEM analysis, and its electrochemical properties were tested with cyclic voltammetry. Formation of $Mn_2O_3$ inside the mesoporous carbon pore system showed much improved electrical properties.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2015.05a
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• pp.166-167
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• 2015

The purpose of this study is to examine the effect on drying shrinkage of self-healing epoxy-modified mortars(EPMMs) using expansive admixtures. The EPMMs are prepared with polymer-binder ratios of 0 and 10%, and tested for drying shrinkage and pore structure analysis. As a result, regardless of the expansion and swelling agent content, the drying shrinkage of the EPMMs is remarkably decreased than that of unmodified mortars. Also, the pore size distribution of the EPMMs is moved to smaller size in comparison with unmodified mortars. In this study, the EPMM with expansive agent 7.5% and swelling agent 2.5% is recommended as a optimal mix proportion for reduction of drying shrinkage.

• Journal of Microbiology
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• v.35 no.3
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• pp.234-238
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• 1997

Conditional lethal mutation nup49-1 of a nuclear pore complex component gene was constructed in Saccharomyces cerevisiae. This mutation deleted one third of the essential NUP49 gene at the carboxy-terminal, but retained 13 repeats of the highly conserved GLFG domain. The nup49-1 mutant strain was viable with a slow-growth phenotype, indicating that the C-terminal is dispensable at normal growth temperature. This strain exhibited both temperature-sensitivity at 37.deg.C and cold-sensitivity at 16.deg.C. Temperature shift experiments revealed that the arrest phenotype at 37.deg.C was random in the cell division cycle. The nup49-1 mutation was tested to be recessive and is expected to be useful for the functional analysis of nuclear pore complex proteins as well as for studies of nuclear transport systems.

• Bulletin of the Korean Chemical Society
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• v.8 no.3
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• pp.150-155
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• 1987

A new method of measurement of pore volume distribution in a porous material by adsorption of gases is proposed. In the newly proposed method the use of spherical molecules with relatively large molecular weight as adsorbates is strongly recommended to eliminate the troubles caused by stereospecificity and low boiling point of widely used $N_2$. It is also claimed that the universal t-curves that have been widely used since proposed by de Boer et al. must be replaced by the flat-surface isotherms that can be derived from the theory proposed by Chang et al. The results of analysis of pore volume distribution based on the method described in this paper are found to be reasonable and satisfactory.

• Journal of the Korean Electrochemical Society
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• v.10 no.4
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• pp.252-256
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• 2007

A series of spherical porous carbons were prepared via resorcinol-formaldehyde (RF) sol-gel polymerization in the presence of cationic surfactant (CTAB, cetyltrimethylammonium bromide), wherein the carbon sphere size was controlled by varying the CTAB introduction time after a pre-determined period of addition reaction (termed as "pre-curing"). The sphere size gradually decreases with an increase in the pre-curing time within the range of 30-150 nm. The carbons possess two types of pores; one inside carbon spheres (intra-particle pores) and the other at the interstitial sites made by carbon spheres (inter-particle pores). Of the two, the surface exposed on the former was dominant to determine the electric double-layer capacitor (EDLC) performance of porous carbons. As the intra-particle pores were generated inside RF gel spheres by gasification, the pore diameter was similar for all these carbons, thereby the pore length turned out to be a decisive factor controlling the EDLC performance. The charge-discharge voltage profiles and complex capacitance analysis consistently illustrate that the smaller-sized RF carbons deliver a better rate capability, which must be the direct result of facilitated ion penetration into shorter pores.