• The Journal of the Korean dental association
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• v.56 no.3
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• pp.159-166
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• 2018

The zirconia-reinforced lithium silicate ceramic material is a material in which lithium silicate glass contains about 10% by weight of zirconia oxide (zirconia oxide). This material has both the advantages of glass ceramics and zirconia, and it is attracting attention as a CADCAM material for single tooth restoration. ZLS materials have improved strength compared to widely used e.max (lithium disilicate ceramic) materials. It can be used for single crown restoration and ensuring a thickness of 1.5 mm is very important for reliable treatment. In the case of Celtra Duo, heat treatment may be helpful in terms of strength and abrasion resistance. Hydrofluoric acid treatment is helpful for bonding and hydrofluoric acid for a short time may not help to improve the bonding strength. Although zirconia-reinforced lithium silicate ceramic materials have been continuously conducted and published in the laboratory, reliable clinical studies are still lacking. Additional clinical studies will be a very important part of establishing a scientific basis.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.5
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• pp.47-54
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• 2018

Concrete undergoes various deterioration on surface. Impregnant with silicate is usually applied to concrete surface and forms insoluble hydrates, which can provide many engineering advantages. In the work, concrete impregnated with colloidal silicate is used for durability enhancement in surface and self-clearing performance is evaluated with photocatalyst-$TiO_2$ spraying. For the work, various tests are performed both for strength evaluation and durability evaluation such as absorption ratio, drying shrinkage, chloride penetration, sulfate resistance, and freezing/ thawing action. Furthermore, removal and self-clearing performance are evaluated with Acetaldehyde decomposition and Methylene blue decolorization. Through silicate impregnation and photocatalyst spraying, the impregnated concrete can have not only durability enhance but also self-clearing performance.

• Membrane Journal
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• v.15 no.4
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• pp.255-271
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• 2005

polymer/layered silicate nanocomposite (PLSNs) is new type of materials, based on clays usually rendered hydrophobic through ionic exchange of the sodium interlayer cation with an onium cation. It could be prepared via various synthetic routes comprising exfoliation adsorption, in situ intercalative polymerization and melt intercalation. The whole range of polymer is used, i.e. thermoplastics, thermosets and elastomers as a matrix. Two types of structure may be obtained, namely intercalated nanocomposites where the polymer chains are sandwiched in between silicate layers and exfolicate nanocomposites where the separated, individual silicate layers are more or less uniformly dispersed in the polymer matrix. This new family of materials exhibits enhanced properties at very low filer level, usually inferior to 5wt$\%$, such as increased mechanical properties, increase in thermal stability and gas barrier properties and good flame retardancy. Gas permeability through the PLSNs films decreased due to increased tortuosity made by intercalation or exfoliation of clay in polymer.

• Korean Journal of Materials Research
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• v.9 no.12
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• pp.1188-1195
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• 1999

The effect of aluminosilicate sol on the formation of mullite layer in zircon shell mold was investigated. Aluminosilicate sol was prepared by mixing of colloidal silica(NALCO(R) 1130) and an aqueous solution of aluminium nitrate at room temperature. The sol gelled at 50$^{\circ}C$ for 48 hrs. It was identified that the gel consists of aluminosilicate complexes and gibbsite. The coordination number of all aluminium ion bonded with silicon ion was four. Mullite phase formed by sintering above 1300$^{\circ}C$. XRD peak of mullite sharpened with increasing sintering temperature and the content of aluminium nitrate. Mullite phase displayed whisker-like 0.5~5${\mu}m $ particles. Separation between 1st and 3rd layers during sintering and the difference in thermal expansion coefficient between residual silica and mullite.

• Polymer(Korea)
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• v.30 no.4
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• pp.311-317
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• 2006

Poly-DCPD and poly-DCPD/silicates hybrids were prepared by in-situ ROMP poly-merization using $WCl_6$ catalyst. Good dispersion of silicates in DCPD medium can be accomplished by sonication method. Compared with nanocomposites prepared using $Na^+MMT$, the nanocomposites with CL 15A showed well dispersed silicate's morphology. superior thermal and mechanical properties. Additionally, well dispersed silicates in DCPD matrix enhanced the gas barrier property of the nanocomposites.

• Proceedings of the KIEE Conference
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• 2008.05a
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• pp.193-195
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• 2008

에폭시-층상실리케이트 나노콤포지트의 여러 가지 특성인 전기적, 기계적, 구조적 특성에 대해서 많은 연구가 진행되었고, 그에 대한 특성 향상을 가져왔다. 그러나 절연성능에 대한 평가는 우수하지만 열적특성 중열전도에 대한 영향은 그히 부족한 상태였다. 열적특성은 열적열화의 원인이 되어 신뢰성에 크게 영향을 준다. 여러종류 Organoclay(10A, 15A, 20A, 30B, 93A)의 에폭기-층상실리케이트 나노콤포지트 Tg 분석결과 10A의 경우 우수한 열적특성을 나타내었다. DNA 점탄성 및 기계적 손실측정에서도 10A의 경우 고온부($140^{\circ}C$) 탄성계수 및 기계적손실 피르가 가장작고, 고온으로 이동되어 발생된 경우로 열적 특성이 우수함을 알 수 있었다. 열전도 측정결과 강력초음파를 적용한 경우와 미적용의 경우 열전도측정으로 볼 때 전반적으로 초음파 적용 경우 열전도향상이 크게 증가된 결과를 얻었다. 향후 몰드 및 함침절연의 전력기기 적용시 유용한 자료로 이용이 가능하여, 더욱더 많은 연구가 필요할 것으로 생각된다.

• Journal of the Korean Chemical Society
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• v.34 no.4
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• pp.360-369
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• 1990

Borosilicate, HZSM-5 zeolite and iron-substituted borosilicate and HZSM-5 zeolite were prepared and their catalytic properties in methanol conversion were studied. The effects of strength and amount of acid site determined from TPD spectra of ammonia on the product distribution was examined. Selectivity to propylene was high over borosilicate with small amount of strong acid site, but selectivity to aromatic compound was high over HZSM-5 zeolite with large amount of the strong acid site. The participation of weak acid site on the conversion did not confirmed, and the product distribution could be explained in terms of the amount of the strong acid site. Although the amount of the weak acid site was increased by substitution of iron, there was no meaningful change in the product distribution.

• Journal of the Korean Chemical Society
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• v.33 no.4
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• pp.379-387
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• 1989

The synthesis of borosilicate consisted of boron and silicon was stadied. The composition, acidity and adsorption characteristics of synthesized borosilicate were examined. The synthesis rate increased with temperature and concentration of $Na_2O$, but the enhansing effects were different according to the reaction conditons. The synthesis process could be simulated by solution transfer mechanism assuming that crystals grow on the surface of crystal or nuclei with dissolved reactant. Adsorption characteristics of synthesized borosilicate was discussed with temperature programmed desorption patterns of ammonia and propylene and adsorption isotherms of propylene and propane.

• Journal of Energy Engineering
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• v.20 no.3
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• pp.171-177
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• 2011

PVA/GLA/$Al_2O_3{\cdot}3SiO_2$ composite membranes were prepared through the reaction polyvinyl alcohol (PVA) with glutaraldehyde (GLA) as a cross-linking agent and subsequently adding aluminum silicate ($Al_2O_3{\cdot}3SiO_2$) as an inorganic material. The water uptake decreased as the GDL contents increased due to cross-linking process of PVA with GDL, and the ion conductivity increased as the $Al_2O_3{\cdot}3SiO_2$ contents increased in PVA/GLA/$Al_2O_3{\cdot}3SiO_2$ composite membranes. The cross-linking structure of the polymers was confirmed using IR and the tendency of water uptake. The thermal analysis of the copolymers was carried out by TGA. TGA results showed that PVA/GLA composite membrane were more heat-resistant than PVA due to the cross-linking of PVA, and the heat stability of the composite membranes improved much more as the concentration of $Al_2O_3{\cdot}3SiO_2$ increased. Membranes prepared in this study seem to be have thermal stability and increase a tendency of the cation conductivity up to $60^{\circ}C$, but to be exhibit lower performance tendency at over $90^{\circ}C$. Therefore, it is necessary to do more aggressive effort to explore the possibility of application as an ion-conductive composite electrolyte.

• Journal of Conservation Science
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• v.21
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• pp.73-88
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• 2007

In this paper, the interaction between five biocides(commercial) and two ethylsilicate consolidants for stone monuments, reacted in different sequence, has been studied. Through the structures, weight and gelation time of mixture of biocides and consolidants have been evaluated the reactivity of biocide alone, the reactivity of consolidants and biocides, the reactivity of consolidants and dried biocide, and the reactivity of ethylsilicate gel and biocides. The tested biocides show quite different properties from those of consolidants; after evaporation, some biocides are remained white salt crystals, another need the long time for evaporation and one biocide shows pale brown color. The results have shown an interaction of the tested products each other in some application sequences of the products. When the application of liquid state biocides with consolidants, it was noted that some biocide seem to interfere with the formation of gel due to reaction of consolidants and water and salts in biocides. In the reaction of ethylsilicate with dried biocides have shown a heterogenous gel(transparent layer with ethylsilicate alone and white layer which is mixed biocide and ethylsilicate) and many cracks in product due to the different shrinkage, thus the products don't play a role as consolidants. There is no change in structures and color in reaction of the gas state biocide and ethylsilicate gel.