• Journal of Technologic Dentistry
• /
• v.35 no.4
• /
• pp.281-286
• /
• 2013

Purpose: Surface modification is important techniques in modern dental and orthopedic implants. This study was performed to try embedding of bioactive materials in porous Ti implants. Methods: Porous Ti implant samples were fabricated by sintering of spherical Ti powders in a high vacuum furnace. It's diameter and height were 4mm and 20mm. Embedding process was used to suction and vacuum chamber. Loading properties of porous Ti implants were evaluated by scanning electron microscope(SEM), confocal laser scanning microscope(CLSM), and UV-Vis-NIR spectrophotometer. Results: Internal pore structure was formed fully open pore. Average pore size and porosity were $10.253{\mu}m$ and 17.506%. Conclusion: Porous Ti implant was fabricated successfully by sintering method. Particles are necking strongly each other and others portions were vacancy. This porous structure can be embedded to bioactive materials. Therefore bioactive materials will be able to embedding to porous Ti implants. Bioactive materials embedding in the porous Ti implant will induced new bone faster.

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 2006.09a
• /
• pp.219-220
• /
• 2006

To understand the effect of powder characteristics on the thermal debinding behavior, PIM parts produced with powders with different particle sizes and particle shapes were examined to determine their weight losses during thermal debinding. The results show that the average diameter of the pore channel in the compact increased when the temperature increased and when coarse powders were used. However, the weight loss rates did not increase proportionally with the pore size. This suggests that the different powders that are frequently used in PIM parts do not affect the thermal debinding rate significantly. This is because the pore size is much larger than the mean free path of the decomposed gas molecules. Thus, the diffusion rates of the gases are not rate-controlling in thermal debinding. The controlling mechanism of the thermal debinding rate is the decomposition of the backbone binder in the PIM parts.

• Journal of Korean Society of Environmental Engineers
• /
• v.30 no.6
• /
• pp.673-679
• /
• 2008

In this study, Mesoporous silica were prepared from hydrothermal synthesis using gel mixture of tetraethylorthosilcate (TEOS) as silica source and cetyltrimethylammonium bromide(CTMABr) as a template. In the optimum synthesis cause, molar ratio of template and silica changed. The surface and structure properties of Mesoporous silica were determined by XRD, SEM, and BET. N$_2$ adsorption isotherm characteristics, including the specific surface area(S$_{BET}$), total pore volume(V$_T$), and average pore diameter(D$_{BJH}$), were determined by BET. Also, the adsorption character of Pb(II) and Cd(II) ion on Mesoporous silica were measured using ICP. As a result, a SBET of 100$\sim$1,500 m$^2$/g was determined from the N$_2$ adsorption isotherm. Also, the average pore diameter of 2$\sim$4 nm. The adsorption of Pb ion and Cd ion on Mesoporous silica become different depending on the pH of solution. The adsorption amount of Mesoporus silica had higher than that of silicagel.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.14 no.4
• /
• pp.160-168
• /
• 2010

Recently, there are a lot of researches related to the high-fluidity concrete (HFC) with field applications. However, most applications and studies are with concretes with high strength level so there are little studies about durability evaluations such as chloride ion penetration properties with normal strength concrete. Therefore, to evaluate the durability of HFC with normal strength level, this study performed the chloride ion penetration test and observed the micro pore distribution with normal strength HFC which contains limestone powder. Experimental results showed that most micro-pores have diameters between 0.005 to 0.05 ${\mu}m$ with HFCs using limestone powder and the average diameter becomes larger with the increase of limestone powder content. Also, it was shown that, with the increase of the limestone powder content, penetration depth and diffusion coefficient of chloride ion increased and diffusion coefficient had good relationships with compressive strength and average pore diameter with the coefficient of determination over 0.90.

• Journal of Environmental Health Sciences
• /
• v.29 no.1
• /
• pp.34-42
• /
• 2003

The objective of this study is to investigate the waste recycling possibility, practicability, economic efficiency and acid gas sorbent use of the hard-shelled mussel. This study is to investigate the hydration/calcination reaction and fixed bed reactor. The physical-chemical characteristics of the hard-shelled mussel were analyzed by ICP SEM-EDX, BET and pore volume. Thus, the results could be summarized as follows; Hard-shelled mussel can be used as iron-manufacture and chemical sorbents considering more than 53.7% of the mussel is lime content. The SO$_2$removal efficiency of the hard-shelled mussel after calcined hydration increased thirty times as a result of the higher pore size, specific surface area and pore volume. Also, the CaO content, pore volume, pore size distribution and specific surface area greatly influenced the SO$_2$ and NOx removal reactivity. The optimum particle diameter average of hard-shelled mussel was $\pm$100 mesh, which was applied to the sorbent on the medium/small scale waste incinerator and flue gas desulfurization processes.

• Journal of the Korean Ceramic Society
• /
• v.55 no.1
• /
• pp.74-79
• /
• 2018

Active clay, bentonite and zeolite were used as porous materials for humidity controlling ceramic boards. The specific area and the pore volume of active clay were higher than those of bentonite and zeolite. It was effective to add white cement as well as a retarding agent to control the setting time of the ceramic paint. As the amount of added porous materials increases, the specific surface area and total pore volume of ceramic paint increase, but the average pore diameter decreases. The addition of porous materials having a high specific area and a large pore volume improves the moisture absorptive and desorptive performance of the ceramic paint. Therefore, in this experiment, the moisture absorptive and desorptive properties were best when active clay was added. Also, as the added amount of porous materials increases, the moisture absorptive and desorptive properties improve. In this experiment, when 70 mass% of active clay was added to ceramic paint, the hygroscopicity was highest at about $80g/m^2$.

• Applied Chemistry for Engineering
• /
• v.9 no.5
• /
• pp.729-733
• /
• 1998

The surface structure and the pore size distribution of the activated carbon impregnated with silver have been investigated. It has been confirmed that the impregnants had an effect only on the external surface, not on the internal surface and that adsorption isotherms of both impregnated and non-impregnated activated carbons were classified as a typical BET type-I. As the amount of the impregnants increased, the amounts of adsorption, the specific surface area, and the micropore volume decreased and the window blocking was observed. The average pore diameter of the activated carbon impregnated with silver was observed to show the constant values regardless of the amount of the impregnants.

• Korean Journal of Materials Research
• /
• v.30 no.4
• /
• pp.155-159
• /
• 2020

Nanoporous silica aerogel insulation material is both lightweight and efficient; it has important value in the fields of aerospace, petrochemicals, electric metallurgy, shipbuilding, precision instruments, and so on. A theoretical calculation model and experimental measurement of equivalent thermal conductivity for nanoporous silica aerogel insulation material are introduced in this paper. The heat transfer characteristics and thermal insulation principle of aerogel nano are analyzed. The methods of SiO₂ aerogel production are compared. The pressure range of SiO₂ aerogel is 1Pa-atmospheric pressure; the temperature range is room temperature-900K. The pore diameter range of particle SiO₂ aerogel is about 5 to 100 nm, and the average pore diameter range of about 20 ~ 40 nm. These results show that experimental measurements are in good agreement with theoretical calculation values. For nanoporous silica aerogel insulation material, the heat transfer calculation method suitable for nanotechnology can precisely calculate the equivalent thermal conductivity of aerogel nano insulation materials. The network structure is the reason why the thermal conductivity of the aerogel is very low. Heat transfer of materials is mainly realized by convection, radiation, and heat transfer. Therefore, the thermal conductivity of the heat transfer path in aerogel can be reduced by nanotechnology.

• Particle and aerosol research
• /
• v.9 no.2
• /
• pp.51-57
• /
• 2013

A graphene(GR)-$TiO_2$ composite was synthesized from colloidal mixture of graphene oxide(GO) nanosheets and $TiO_2$ nanoparticles by an aerosol assisted self-assembly. The morphology, specific surface area and pore size of asprepared GR-$TiO_2$ composite were characterized by FE-SEM, BET, and BJH respectively. The shape of GR-$TiO_2$ composite was spherical. The average particle size was 0.5-1 ${\mu}m$ in diameter and the pore diameter ranged 20-50 nm. Photovoltaic characteristics of a mixture of the GR-$TiO_2$ and $TiO_2$ nanoparticles were measured by a solar simulator under simulated solar light. The highest photoelectric conversion efficiency of the mixture photoanode was 5.1%, which was higher than that of $TiO_2$ photoanode.

• Journal of the Korean Ceramic Society
• /
• v.29 no.11
• /
• pp.893-899
• /
• 1992

Composite specimens, which are composed MDF cement of HAC-PVA system were prepared by adding carbon fiber, hydrated silica and SiC powder, and we studied effect of additives on the flexural strength of the composites. All of additives is effective in the improvement of flexural strength of the composite specimens. The size of average pore diameter in the specimens which have high flexural strength property was small. Specimen mixed with hydrated silica was effective in the particle compact property. Flexural strength of carbon fiber reinforced MDF cement composites were improved because of crack deflection of carbon fiber in cementitious matrix.