• Journal of the Korean Ceramic Society
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• v.35 no.10
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• pp.1085-1093
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• 1998

Amorphous alumina powder prepared by the fast calcination of aluminum trihydroxide(Al(OH)3 gibbsite) for 0.5 second at 580$^{\circ}C$ was investigated rehydration propeties. Phase composition crystal size and mor-phology surface area pore volume and pore size distribution of pesudo-boehmite and bayerite crystals changed with temperature time water/alumina ratio and particle size when amorphous alumina rehydrated with water. Phase compositions were examined with XRD and DTA and crystal sized morphologies were investigaed with SEM and TEM. Also rehydration properties of amorphous alumina were in-vestigated by measuring the surface area pore volume and pore size distribution.

• Computers and Concrete
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• v.11 no.4
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• pp.317-336
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• 2013

In this study, the pore structure of Portland cement paste is experimentally characterized by MIP (mercury intrusion porosimetry) and nitrogen adsorption, and simulated by a newly developed status-oriented computer model. Cement pastes with w/c=0.3, 0.4 and 0.5 at ages from 1 day to 120 days are comprehensively investigated. It is found that MIP cannot generate valid pore size distribution curves for cement paste. Nevertheless, nitrogen adsorption can give much more realistic pore size distribution curves of small capillary pores, and these curves follow the same distribution mode. While, large capillary pores can be effectively characterized by the newly developed computer model, and the validity of this model has been proved by BSE imaging plus image analysis. Based on the experimental findings and numerical simulation, a hypothesis is proposed to explain the formation mechanism of the capillary pore system, and the realistic representation of the pore structure of hydrated cement paste is established.

• Journal of the Korean Ceramic Society
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• v.36 no.6
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• pp.662-670
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• 1999

Porous alumina was fabricated from pressureless powder packing forming method using powders granulated by spray drying. It was investigated the pore size distribution of fabricated porous alumina. The results of microstructural observation showed that intraganular pore size and intragranular pore size. At 1700$^{\circ}C$ there were no intragranular pores but it showed homogeneous distribution of intergranular pore size. The bending strength and shrinkage increased as porosity decreased. In case of thermal shock resistance sudden decrease of bending strength to $\Delta$T was not shown because intergranular large pore prevented sudden crack propagation.

• Journal of the Korean Ceramic Society
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• v.40 no.6
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• pp.572-576
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• 2003

Open/closed porosity, pore size and its distribution and pore type as a funtion of sintered density of UO$_2$-20 wt％CeO$_2$ pellets were investigated. Pore appeared almost closed-type with the density above 96％ of the theoretical density. Bimodal pore size distribution was observed regardless of the sintered density, but the number of pore decreased with increasing the sintered density. The shape of pore was changed from irregular shape to round type with increasing the sintered density.

• Restorative Dentistry and Endodontics
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• v.46 no.4
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• pp.57.1-57.9
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• 2021

Objectives: This study aimed to compare and evaluate the porosity and pore size distribution of high-viscosity glass ionomer cements (HVGICs) and conventional glass ionomer cements (GICs) using micro-computed tomography (micro-CT). Materials and Methods: Forty cylindrical specimens (n = 10) were produced in standardized molds using HVGICs and conventional GICs (Ketac Molar Easymix, Vitro Molar, MaxxionR, and Riva Self-Cure). The specimens were prepared according to ISO 9917-1 standards, scanned in a high-energy micro-CT device, and reconstructed using specific parameters. After reconstruction, segmentation procedures, and image analysis, total porosity and pore size distribution were obtained for specimens in each group. After checking the normality of the data distribution, the Kruskal-Wallis test followed by the Student-Newman-Keuls test was used to detect differences in porosity among the experimental groups with a 5% significance level. Results: Ketac Molar Easymix showed statistically significantly lower total porosity (0.15%) than MaxxionR (0.62%), Riva (0.42%), and Vitro Molar (0.57%). The pore size in all experimental cements was within the small-size range (< 0.01 mm³), but Vitro Molar showed statistically significantly more pores/defects with a larger size (> 0.01 mm³). Conclusions: Major differences in porosity and pore size were identified among the evaluated GICs. Among these, the Ketac Molar Easymix HVGIC showed the lowest porosity and void size.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.7
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• pp.1078-1084
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• 2002

Cotton fabrics were treated with 1,2,3,4-butanetetracarboxylic acid(BTCA) to impart durable press performance, which is formaldehyde-free DP finishing reagent. The pore structures of BTCA treated cottons were compared using a reverse gel permeation chromatographic technique(reverse GPC). A series consisting 4 kinds of water soluble sugars was used to study the elution characteristics of columns prepared from cotton fibers. From these data, differences in pore size distribution in the control and BTCA treated cottons were distinguished. BTCA crosslinks cellulose molecules provided wrinkle resistance to the treated cotton fabrics through ester linkages. Although crosslinking of cotton with BTCA reduced accessible internal volume across the entire range of pore size, differences in line pores were larger than in small pores. BTCA treated cotton exhibited reductions over 40% in large pore sizes.

• Proceedings of the Membrane Society of Korea Conference
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• 1991.10a
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• pp.4-8
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• 1991

The characterization of pore properties (mean pore size and pore size distribution) of the active layer in a UF membrane is important not only in order to obtain information about the factors affecting pore formation during membrane manufacturing but also to understand deeply the mechanism of solute and solvent transport through pores. Many methods of characterizing quantitatively the pore properties of UF membranes have been suggested in the literature: solvent and gas flow measurement, bubble point determination, electron microscopy, gas adsorption/desorption measurement, rejection measurement etc. But most of these methods involve time-consuming procedures and involve some wellknown problems and uncertainties.

• Korean Journal of Crystallography
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• v.9 no.1
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• pp.64-70
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• 1998

Porous body was prepared from coal fly ash 70 wt%0clay 30 wt% slip using DCC(Direct Coagulated Casting) method. Effect of the specific gravity of the slip on the pore size and distribution of the sintered body was examined by the SEM observation of microstructure and mercury porosimetry measurement of the pore size distribution. Average pore size of the porous sintered body was about 2.5μm for all slips with specific gravity of 1.55, 1.60 and 1.65g/cm3, respectively. Sintered body prepared from the slip of specific gravity of 1.60g/cm3 have the narrowest pore size distribution. slip of specific gravity of 1.55g/cm3 shows broader pore size distribution due to slow gellation process. Slip of specific gravity of 1.65g/cm3 required large amount of deflocculant and showed large variation of the viscosity with addition of coagulant which resulted in very unstable slip properties.

• Journal of the Korean Ceramic Society
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• v.31 no.2
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• pp.137-146
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• 1994

This experiments were focused on a modification of mechamical properties and structure in porous aluminum titanate ceramics by new additives which have been not researched yet. These were consisted of four kinds of additives i.e. Bi2O3, FeO, ZnO and NiO by addition amount of 1 wt% and 5 wt% respectively. The addition of Bi2O3 retarded a degree of syntehsis of aluminum titanate and accelerated in FeO, ZnO, NiO additives. Also, the most effective accelerator in synthesis of alunium titanate was FeO. A additives for the most effective of modification of microstructure, sharp distribtion of pore size and mechanical proterties was on ZnO addition and showed the lowest average pore size and narrowed pore size distribution. In order to improve of microstructure and pore size distribution in porous aluminum titanate ceramics was desired the addition amount of 1 wt% compare to 5 wt%.

• Textile Coloration and Finishing
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• v.21 no.4
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• pp.57-62
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• 2009

N-Halamines are compounds which have covalent bonding between nitrogen and halogen. N-Halamine materials possess strong antimicrobial properties against wide spectrum of bacteria. The aim of this study is to prepare N-halamine membranes using m-aramid and poly(vinyl alcohol) (PVA). Surface characteristics using scanning electron microscope (SEM), pore size distribution, liquid permeability and mean pore size were measured to confirm feasibility as membrane. The results indicated that increased PYA portion up to 15% in the m-aramid/PVA blend resulted in improved pore size distribution, liquid permeability as well as mean pore size. Furthermore, antibacterial efficacy of the membranes after chlorination was confirmed and the results showed that bacteria in water were inactivated.