• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.05a
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• pp.286-286
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• 2004

초고속 정보통신망 구현에 필수적인 광학 연결용 부품인 광 Ferrule은 광섬유 커넥터의 중요부품으로서 우수한 치수정밀도와 내마모성을 갖추어야 한다. 현재, Ferrule로 사용되는 재료는 지르코니아, 알루미나 등 세라믹 물질이 많이 사용되고 있으며 기계적 강도나 내마모성 면에서는 우수하지만, 피연마속도가 석영섬유에 비해 현저히 작아서 특수한 연마방법을 채택해야 하며 성형성이나 가공성이 나빠 생산효율이 낮고 비용이 비싸다는 단점을 가지고 있다.(중략)

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1425-1427
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• 1994

Laser ablation of glass substrates (8K-7 and synthetic quartz) using a transversely excited atmospheric (TEA) $CO_2$ laser has been inverstigated to obtain high speed etching. The ablation occurs by local heating of a substrate with a focused TEA-$CO_2$ laser beam. The dependence of ablation rate on pulse count and repetition-rate of laser has been discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.628-630
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• 2000

Since the concept for the ozone generation using a nonequilibrium electric discharge techniques had been proposed by Siemens, some experimental and theoretical studies on the ozone generation by streamer corona discharge, surface discharge and silent discharge have been performed. In this paper some results on the discharge characteristics of the silent discharge gap with various dielectric materials were reported. Dielectric materials used in this study were pyrex glass, quartz and glass beefs with diameter of 1 mm.

• Korean Journal of Materials Research
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• v.4 no.6
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• pp.611-619
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• 1994

The formation of , $\beta$-quartz solid solution in the $LiO_2-Al_2O_3-SiO_2$glasses containing $TiO_{2}$ and $ZrO_{2}$ as nucleating agents was investigated for various temperatures and times. Linear thermal expansion coefficients of base glasses and crystallized glasses were $45\sim 55 \times 10^{-7} \textrm{cm}/^{\circ}C$ and $ -8\sim +8 \times 10^{-7}\textrm{cm}/^{\circ}C$ ($25^{\circ}C \sim 525^{\circ}C$), respectively. The crystal phase formed by heat-treatment below $900^{\circ}C$was , $\beta$--quartz solid solution, and the crystal sizes were less than 0.21m. On the other hand, the crystal size of the base glasses containing 3.5 wt% MgO is relatively uniform and is independent with temperature. The specimen containing 3.5 wt% ZnO shows a minimum crystal size(O.l8$\mu \textrm{m}$), and it strongly depends on temperature of heat-treatment.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.2
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• pp.74-81
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• 2014

Purpose: While studies have examined microleakage in endodontically treated teeth restored with posts, microleakage among post and adhesive systems remains a concern. This study compared the sealing properties of 3 adhesively luted post systems. Materials and methods: Thirty-six endodontically treated permanent maxillary central incisors were divided into 3 groups: Zirconia-glass fiber, Quartz-glass fiber, Polyethylene fiber posts. Post space was prepared and each post was adhesively luted with 3 systems. The specimens were separately immersed in freshly prepared 2% methylene blue solution for 1 week. The cleaned specimens were then embedded in autopolymerizing acrylic resin. The root portion of tooth were horizontally sectioned into three pieces (apical, middle, and coronal portions). An occlusal view of each section was digitally photographed with a stereomicroscope. The methylene blue-infiltrated surface for each specimen was measured. Dye penetration was estimated as the ratio of the methylene blue-infiltrated surface to the total dentin surface. Results: No significant differences were found among post types. The variables of middle section and 3-stage adhesive produced significant differences in microleakage between the following post pairs: zirconia-glass fiber versus quartz-glass fiber, zirconia-glass fiber versus polyethylene fiber, and quartz-glass fiber versus polyethylene fiber (P<.05). There were significant differences between the apical and coronal sections of each post type, and between apical versus middle sections of quarze-glass fiber and polyethylene fiber posts (P<.05). Conclusion: No significant differences were found among post types. The 3-stage adhesive produced significant differences in microleakage between the following post pairs.

• Journal of the Semiconductor & Display Technology
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• v.21 no.1
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• pp.119-126
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• 2022

MAS-based glass, which has been studied to replace the ceramic material used in the plasma etching chamber, has problems such as forming and processing due to its high melting temperature. To solve this problem, in this study, fluoride was added to the existing MAS-based glass to increase the workability in the glass manufacturing and to improve the chemical resistance to CF₄/Ar/O₂ plasma gas. Through RAMAN analysis, the structural change of the glass according to the addition of fluoride was observed. In addition, it was confirmed that high-temperature viscosity and thermal properties decreased as the fluoride content increased and plasma resistance was maintained, it showed an excellent etching rate of up to 11 times compared to quartz glass.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.159-162
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• 2000

The purpose of this study is to develope an accurate procedure for measuring the glass content of fly ash produced by bituminous coal to assist in predicting their behavior in concrete. Quantitative mineralogical compositions of fly ashes were obtained by internal standard method using powder X-ray diffraction analysis. In the X-ray diffraction method, the specimen and standard fluorite were cautiously mixed and pulverized to 22$\mu$m in wet process so as to avoid the prefered orientation of the crystal and microabsorption effect of X-ray. calibration curve were fitted for several references peaks of four phases:$\alpha$-quartz. mullite, magnetite, hematite. The amount of glass was calculated by subtracting the amount of crystal phase and loss on ignition from the total amount. Glass content determined with this method ranged from 66.7 to 75.wt%.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.05a
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• pp.219-223
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• 2005

Nowadays laser cutting is the most promising method of cutting FPD(Flat Panel Display) glass in mass-production line. And this method can also be used to cut other brittle materials such as quartz, sapphire, ceramic and semiconductor The concept of this method is shown in picture 1. Laser beam heats glass up to strain point, not to melting point and cooling system chills glass to induce maximun thermal stress in glass surface and then the thermal stress generates micro thermal crack, in other words blind depth of crack, along laser beam and cooling line.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2004.10a
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• pp.50-61
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• 2004

Nowadays Laser Controllable Thermo-cleaving is the most promising method of cutting FPD(Flat Panel Display) glass in mass-production line. And this method can be used to cut other brittle materials such as quartz, sapphire, ceramic and semiconductor. The concept of this method is shown in Picture 1. Laser beam heats glass up to strain point not to melting point and cooling system chills glass to make maximum thermal stress in glass and then the thermal stress generates micro thermal crack in other words blind crack. Laser Controllable Thermo-cleaving controls the thermal stress to optimize the blind crack up to level of mass-production line.

• Journal of the Korean institute of surface engineering
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• v.46 no.3
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• pp.99-104
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• 2013

The simple and cost-effective microfabrication method of photosensitive glass (PSG) using metal patterning and blank exposure was proposed. Conventional photolithography for micromachining of PSG needs a costly quartz mask which has high transmittance as an optical property. However, in this study the process was improved through the combination of micro-patterned Ti thin film and blank UV exposure without quartz mask. The effect of UV exposure time as well as the DHF etching condition was investigated. UV exposure test was performed within the range from 3 min to 9 min. The color and etch result of PSG exposed for 5 min were the most clear and effective to etch more precisely, respectively. The etching results of PSG in diluted hydrofluoric acid (DHF) with a concentration of 5, 10, 15 vol% were compared. The effect on the side etch was insignificant while the etch rate was proportional as the concentration increased. 10 vol% DHF results not only high etch rate of 75 ${\mu}m/min$ also lower side etch value after PSG etching. This method facilitates the microfabrication of PSG with various patterns and high aspect ratio for applying to advanced applications.