• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.05a
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• pp.245-249
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• 2004

Transparent materials such as fused silica are important materials in optical and optoelectronics field because of its outstanding properties, such as transparency in a wide wavelength range, strong damage resistance for laser irradiation, and high thermal and chemical stability. However, these properties make it difficult to micromachine silica in micro-sized quantities. In this study, we fabricated a micro patterns on the surface of fused silica plate using laser induced wet etching. KrF excimer laser was used as a light source. There were no burrs and micro cracks on the etched surface of fused silica and the flatness of the etched surface was fairly good. We investigated the influence of etchant upon the etch rate and quality in laser induced wet etching. Pyrene-acetone, toluene, and pyrene-toluene solution were used as etchant. In the side of etch rate, toluene and pyrene-toluene solution were better than pyrene-acetone solution.

• Transactions of Materials Processing
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• v.13 no.3
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• pp.268-272
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• 2004

Transparent materials such as fused silica are widely utilized in optical and optoelectronics field because of its outstanding properties, such as transparency in a wide wavelength range, strong damage resistance for laser irradiation, and high thermal and chemical stability. In this study, we made a few micro patterns on the surface of fused silica plate using laser induced wet etching. KrF excimer laser was used as a light source. There were no burrs and micro cracks on the etched surface of fused silica and the flatness of the etched surface was fairly good. We investigated the influence of etchant upon the etch rate and quality in laser induced wet etching. Pyrene-acetone solution and toluene were used as etchant. In the side of etch rate, toluene solution was better than pyrene-acetone solution. But we made in wider range of energy density using pyrene-acetone solution. But pyrene-acetone solution gave us wider window of energy density for successful micro patterning.

• Transactions of Materials Processing
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• v.11 no.7
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• pp.601-607
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• 2002

Optically transparent materials such as fused silica, quartz and crystal have become important in the filed of optics and optoelectronics. Laser ablation continues to grow as an important technique for micromachining and surface modification of various materials, because many problems caused by direct contact between tools and workpiece can be avoided. Especially, laser ablation with excimer lasers enables fine micromachining of transparent materials such as fused silica, quartz and crystal, etc. In this study, laser-induced wet etching of fused silica in organic solution was conducted. KrF excimer laser was used as a light source and acetone solution of pyrene was used as etchant. Changing the number of laser pulses, micro holes of various depths are fabricated.

• Applied Biological Chemistry
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• v.14 no.3
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• pp.183-189
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• 1971

The studies reported herein were conducted to inquire the effect of fused siliceous materials which mixed with sand and quartz added calcium fertilzer on rice grown on low available silica content soil. The applied nitrogen level were examined for the two plots, nitrogen 10kg and 20kg per 10 a., and the siliceous materials(Wollastonite, Fused sand and Fused quartz) were applied as levels to 100kg, 300kg and 500kg per 10a. in the pots. The results are summerized as follows; 1. The available silica content solved in N/2 HCl solution of fused sand was more than of fused quartz but the silica solubility in 2% citric acid of fused quartz were higher than other. 2. The absorbed silica content by plant grown on the fused quartz plot was the highest among other siliceous materials and of fused sand and natural wollastonite were at almost equal. The ratio of absorbed silica of natural wollastonite was highest among them and in fused materials, the quartz was higher than sand. 3. The productivity of rice was increased by percentage of filled grain, weights of 1000 grains, and number of spikelets on account of the large quantity of the silica absorbed by plant Especially fused quartz showed the highest productive effect among siliceous materials and natural wollastonite and fused sand were similar effect. 4. From the above results. the fused quartz was selected as expelled siliceous fertilizer on rice plant among them and the fused sand was equal effect to natural wollastonite.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.78-83
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• 2009

In general, Light-hardening polymer was used UV nanoimprint technology. A light-hardening polymer was had the problem of poor hardness, durability. In order to overcome the problem of polymer, inter change optical glass. However glass is very manufacture and a lowering of standars transmittance. In order to glass recover was necessary polishing process. The process is magnetorheological fluids polishing. MR polishing has been developed as a new precision finishing technique to obtain a fine surface. Hence, Magnetorheological fluids has been used for micro polishing to get micro parts. This polishing process guarantees high polishing quality by controlling the fluid density electrically. The applied material in experiments is fused silica glass. Fused silica glass is widely used in the optical field because of high degree of purity. For MR polishing experiments, MR fluid was composed with DI-water, carbonyl iron and nano slurry ceria. The wheel speed and electric current were chosen as the variables for analyzing the characteristics of MR polishing process. Outstanding surface roughness of Ra=1.58nm was obtained on the fused silica glass specimen. And originally glass transmittance was recover on the fused silica glass.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1803-1805
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• 1999

The thermal expansion coefficient of the titania-fused silica glass$(TiO_2-SiO_2)$ called KLR-1.1 is known to $0{\pm}0.03$ ppm/K, while that of normal fused-silica glasses is about +0.5 ppm/K at room temperature. To analysis the dielectric properties of the KLR-1.1, the sample with diameter of 30 mm and thinkness of 1 mm is covered with gold film. Its relative permittivity and dissipation factor of KLR-1.1 is evaluated to $4.011{\pm}0.012(1\sigma)$ and $(4.86{\pm}0.02){\times}10^{-4}(1{\sigma})$ at 1 kHz respectively. The measurement techniques used and results are more discussed in this paper.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1344-1348
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• 2003

It is generally known to be difficult to etch a surface of a transparent material such as fused silica by conventional laser ablation in which the surface is simply irradiated with a laser beam. A lot of studies have been done to provide a method capable of efficiently etching transparent materials without defects such as cracks. One of the promising methods or the micro-machining of optically transparent materials is laser induced etching. In this study, micro-drilling of fused silica by laser induced wet etching was conducted. KrF excimer and YAG laser were used as light sources. Acetone solution pyrene and ethanol solution of rhodamine were used as etchant.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.5
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• pp.761-766
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• 2012

Abrasive fluid jet polishing processes have been used for the polishing of optical surfaces with complex shapes. However, unstable and unpredictable polishing spots can be generated due to the fundamental property of an abrasive fluid jet that it begins to lose its coherence as the jet exits a nozzle. To solve such problems, MR fluid jet polishing has been suggested using a mixture of abrasives and MR fluid whose flow properties can be readily changed according to imposed magnetic field intensity. The MR fluid jet can be stabilized by imposed magnetic fields, thus it can remain collimated and coherent before it impinges upon the workpiece surface. In this study, MR fluid jet polishing characteristics of fused silica glass were investigated according to injection time and magnetic field intensity variations. Material removal rates and 3D profiles of the generated polishing spots were investigated. From the results, it can be confirmed that the developed MR fluid polishing system can be applied for stable and predictable precise polishing of optical parts.

• Design & Manufacturing
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• v.14 no.1
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• pp.36-41
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• 2020

Recently, due to the development of MEMS technology, researches for the production of effective micro structures and shapes have been actively conducted. However, the process technology based on chemical etching has a number of problems such as environmental pollution and time problems due to multi-process. Various processes to cope with this process are being studied, and one of the mechanical etching processes is the powder blasting process. This process is a method of spraying fine particles, which has the advantage of being an effective process in manufacturing hard brittle materials. However, it is also a process that adversely affects the material surface roughness and material properties due to the impact of the injection of fine particles. In this study, after fabricating micro-channels in fused silica glass with excellent optical properties among the hard brittle materials, we used the nano indentation system to analyze the micro parts using nano-particles as well as machinability and surface roughness analysis of the processed surface. The analysis was performed for the effective processing of powder blasting.

• Korean Journal of Materials Research
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• v.21 no.9
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• pp.482-485
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• 2011

$La_{0.6}Sr_{0.4}MnO_3$ (LSMO) thin films, which are known as colossal magnetoresistance materials, were prepared on fused silica thin films by conventional RF magnetron sputtering, and the interfacial reactions between them were investigated by rapid thermal processing. Various analyses, namely, X-ray diffraction, transmission electron microscopy combined with energy adispersive X-ray spectrometry, and secondary ion mass spectrometry, were performed to explain the mechanism of the interfacial reactions. In the case of an LSMO film annealed at $800^{\circ}C$, the layer distinction against the underplayed $SiO_2$ was well preserved. However, when the annealing temperature was raised to $900^{\circ}C$, interdiffusion and interreaction occurred. Most of the $SiO_2$ and part of the LSMO became amorphous silicate that incorporated La, Sr, and Mn and contained a lot of bubbles. When the annealing temperature was raised to $950^{\circ}C$, the whole stack became an amorphous silicate layer with expanded bubbles. The thermal instability of LSMO on fused silica should be an important consideration when LSMO is integrated into Si-based solid-state devices.