• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1734-1741
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• 2023

This work presents the synthesis and preparation of a new glass system described by the equation of (70-x) B₂O₃-5TeO₂ -20SrCO₃-5ZnO -xBi₂O₃, x = 0, 1, 5, 10, and 15 mol. %, using the melt quenching technique at a melting temperature of 1100 ℃. The photon-shielding characteristics mainly the linear attenuation coefficient (LAC) of the prepared glass samples were evaluated using Monte Carlo (MC) simulation N-particle transport code (MCNP-5) at gamma-ray energy extended from 59 keV to 1408 keV emitted by the radioisotopes Am-241, Ba-133, Cs-137, Co-60, Na-22, and Eu-152. Furthermore, we observed that the Bi₂O₃ content of the glasses had a significantly stronger impact on the LAC at 59 and 356 keV. The study of the lead equivalent thickness shows that the performance of fabricated glass sample with 15 mol.% of Bi₂O₃ is four times less than the performance of pure lead at low gamma photon energy while it is enhanced and became two times lower the perforce of pure lead at high energy. Therefore, the fabricated glasses special sample with 15 mol.% of Bi₂O₃ has good shielding properties in low, intermediate, and high energy intervals.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.25 no.6
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• pp.263-271
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• 2015

Commercial AR(Alkali Resistant)-glass fiber has a good chemical resistant property, but also has a problem of difficulty in fiberizing process because of high viscosity in melted glass compare with E-glass fiber which is the most widely used for reinforced fiber of composite materials. In this study, we fabricated AR-glass fiber with low zirconia contents compare with commercial AR-glass fiber relatively, and measured properties against E-glass fiber. We obtained transparent clear glass with zirconia contents of 0.5~16 wt% by melting at $1600^{\circ}C$ for 2 hours. These AR-glass samples had high visible transmittance of 89~90 %, softening temperature of $703{\sim}887^{\circ}C$. And softening temperatures of them were increased according to the increasing zirconia contents. Compare with E-glass, AR-glass contains 4 wt% zirconia has different value of $-94^{\circ}C$ in softening temperature, $+68^{\circ}C$ at Log3 temperature and $-13^{\circ}C$ at Log5 temperature in viscosity. We could verify good alkali resistant property of the AR-glass fiber with SEM after dipping in alkali solution for 48~72 hours, and also high tensile strength, 1.7 times compare with E-glass fiber at 48 hours and 2.2 times at 72 hours. We conclude that this AR-glass fiber can be widely used as general alkali resistant glass fiber because of easy manufacturing condition and good properties even though it has low zirconia contents.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.337-337
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• 2009

가시광선영역에서 매우 균일한 높은 투과성뿐만 아니라 근적외선영역에서 가파른 홉수성 엣지와 함께 낮은 투과율을 제공하는 산화구리(II)를 함유하는 포스페이트 유리는 컬러 비디오 카메라의 컬러 보정 필터, 발광 컬러 디스플레이용 보호판(sheild), 모노크로메이터의 미광 필터, 플라스틱 복합재 필터의 무기 성분 및 CCD(전하 결합 소자) 및 CMOS(상보성 금속 산화물 반도체) 카메라 및 검출기 분야용 필터 유리로서 사용된다. 용융온도 및 산화구리(II) 첨가량에 따른 투과율을 측정하기 위해 포스페이트 유리 시료를 $1100\sim1500^{\circ}C$ 용융한 후 $400^{\circ}C$에서 2시간 동안 어닐링 공정을 거쳐 제조하였다. 제조된 시료는 두께 0.3mm로 폴리싱하여 자외선-적외선 분광 광도기를 이용하여 광학적 특성을 측정하였다. 본 실험을 통하여 용융온도에 따라 가시광선영역 및 근적외선영역에서의 투과율 거동을 비교한 결과 $1100\sim1200^{\circ}C$에서의 우수한 투과율 특성을 나타냈다. 용융온도가 내려감에 따른 가시광선영역 (400~600nm)에서 높은 투과율 및 근적외선영역 (750~1100nm)에서 낮은 투과율과 가파른 흡수성 엣지를 나타냈다.

• Journal of the Korean Ceramic Society
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• v.35 no.4
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• pp.319-324
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• 1998

Sol-gel derived phosphate water-sioluble glasses containing Cu were prepared. Powder-shape of glasses were added in D.I water used polyethylene bottle. After solution contained glass powder were submerged in water bath on 25$^{\circ}C$ their dissolution behavior/characteristics bactericidal effect and cytotoxicity test were evaluated. The maximum amount of Cu(35 mol%) via sol-gel method was more 5 mol% increased than that with melting process. The stage of total dissolution was more dominant than that of selective leaching dur-ing dissolution due to dissolved amount of glasses increased linearly with time. The ratio of Cu+ to {{{{ {Cu }^{2+ } }} was 3:7 so that the structure of glasses is more predominant 2-dimension chain structure than 3-dimenshion po-lymeric structue. The stage of total dissolution was more dominant than that of selective leaching during dissolution. Bactericidal effect against all bacteria showed that solutions which contained 40 ppm and 100 ppm of Cu killed 80 percentages of bacteria within 2 hours and 100 percentages of those within 12 hours. The results of cytotoxicity test for L929 cells showed no cytotoxicity were observed within 96 hours for dis-solved solution that contains 40 ppm and 100 ppm of Cu.

• Journal of the Korean Ceramic Society
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• v.44 no.1 s.296
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• pp.1-5
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• 2007

Fining and homogenization of melts during batch melting is closely related to the redox reaction of polyvalent element M (M: Sb, As etc), $M^{(x+n)+}+n/2O^{2-}{\rightarrow}M^{x+}+n/4O_2$. In this study, square wave voltammetry (SWV) measurements were performed to examine the redox behavior of an antimony ion in cathode ray tube (CRT) glass melts. According to results, well-separated two peaks are shown at low temperature while only one peak is shown at high temperature in voltammograms, which reveals that redox reaction of antimony consist of two steps: $Sb^{5+}/Sb^{3+}\;and\;Sb^{3+}/Sb^0$, depending on the temperature. Based on the peak potential shown in the voltammogram, the thermodynamic data and the redox ratio for two redox couple were determined.

• Macromolecular Research
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• v.13 no.3
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• pp.212-217
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• 2005

The pyrolysis kinetics of polyurethanes synthesized from polycaprolactone diol (PCL) and diisocyanate (HDI, $H_{12}MDI$) using catalysts such as dibutyltin dilaurate (DBTDL) were studied by a thermogravimetric (TG) technique, which involved heating the sample at the rates of 10, 20 and $30^{\circ}C$/min. The effect of the kind of diisocyanate and the hard segment contents on the activation energy and reaction order were examined at conversions ranging from 1 to $100\%$. The activation energies at first increased slowly with increasing conversion. Also, differential scanning calorimetry (DSC) was used to investigate the structural differences in each polyurethane. DSC can reveal the melting behavior, in terms of the glass transition temperature ($T_g$), which is known to vary as a function of the stoichiometry and processing conditions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.3
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• pp.161-165
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• 2002

Ge-doped rnulticomponent oxide glasses were prepared by a conventional melting method. The change of micro structure in glasses was investigated by using PL (photoluminescence) and ESR (electron spin resonance). Before UV irradiation, the PL intensity increased according to germanium contents, but decreased the intensity as soon as UV irradiation. A changed property was recovered near it original properties when it was annealed. These photodarkening and thermal bleaching effect were observed by ESR intrument. These effect did not change the glass phase but vary only change of micro structure.

• Journal of the Korean Ceramic Society
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• v.42 no.3 s.274
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• pp.193-197
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• 2005

Wall and floor tiles were fabricated by a dry pressing method using waste glass and clay. The physical properties of the tiles such as absorption, bulk density, porosity, compressive strength, and abrasion loss are investigated with the firing temperature and glass contents. The physical properties are improved with increasing the firing temperature and glass contents. The composition containing the glass of $70 wt%$ and fired at $1050^{\circ}C$ for 2 h has the good properties. The optimal properties obtained in the tiles are the water absorprion of about $0.9\%$, the bulk density of about $2.3\;g/cm^3$, the apparent porosity of about $2.1 \%$, the compressive strength of about 210 MPa, and the abrasion loss of about 0.022 g, when the composition containing the glass of $70\;wt\%$ is fired at $1050^{\circ}C$. The physical proper1ies of tiles fabricated were enhanced compared to the commercial clay tiles, due to easy melting and densification of glassy phase during the firing process.

• Journal of the Korean Ceramic Society
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• v.25 no.5
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• pp.541-551
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• 1988

The purpose of this investigation was to prepare multicomponent monolithic Li-Al-Si gels of composition(mol%) 16.67 Li2O-16.67 Al2O3-66.67 SiO2 and to convert the gels to monolithic glass-ceramic at low temperature without melting. The hydrolysis, DTA, TGA, TMA, SEM, pore distribution, density and the activation energy for crystallization of the glass-ceramic formation with rawmaterials of which tetraethl orhosilicate of networkforming cation(Si) is partially hydrolyzed, aluminum isoproxide and lithium methoxide prepared by Li-metal react with methanol were studied. The results were as follows : 1) Monolithic gels which were added with additional water, resulting in a total water content 2.5 to 3.0 times the stoichiometric amount required to fully hydrolyze the alkoxides. 2) Specimens were dried to form crylinders 60mm in length and 40mm in diameter in about 800 hrs at 5$0^{\circ}C$. 3) $\beta$-eucryptite crystals and $\beta$-spodumene crystals were detected in samples heated above 75$0^{\circ}C$. 4) Within the temperature and range of 25-50$0^{\circ}C$ and 1,00$0^{\circ}C$ the thermal expansion coefficient for crystallized samples were shown as 2.6-5.7$\times$10-7/$^{\circ}C$ and 7.4-12.5$\times$10-7/$^{\circ}C$, respectively. 5) The activation energy for the crystal growth was 11.01kcal/mol at 794$^{\circ}C$ to 85$0^{\circ}C$.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.2
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• pp.511-516
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• 2013

The thickness and deflection of melting parts of the glass edge reach the biggest effect on the intensity and thermal insulation performance. During the sealing process using a hydrogen mixed gas torch, the thickness and the deflection effect of the edge part are affected by process parameters. In order to analyze the correlative relationship of the thickness prediction and the deflection of the edge part according to the process parameters, data was obtained by conducting sealing experiments. The main effects and interaction effects of process parameters for the thickness and the shape of the glass edge parts were analyzed through the design of experiment. A mathematical experiment equation that can predict the thickness and deflection of the edge part according to the process parameters was developed by conducting multiple regression equations.