• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.69-69
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• 2010

현대 건축물에서 건물에너지의 손실은 대부분은 창호를 통하여 유출되어지고 있으며 에너지 절감을 위해서는 창호의 단열성을 향상시켜야한다. 저방사(Low Emissivity) 코팅유리는 건축물의 냉난방비용을 절약할 수 있는 대표적인 건축재료로써 외부에서 유입되는 태양광의 가시광선 영역은 높은 투과율을 가지면서 적외선 영역과 겨울철 실내 난방열을 반사하는 특징을 지니는 박막코팅기술이다. 이 코팅유리는 일반적으로 유전체/금속/유전체 다층박막 구조로 되어있으며, 유전체층은 내구성 증진과 금속층의 반사를 낮추어 투과율이 향상된다. 금속층은 적외선영역의 복사에너지를 반사하는 역할을 하며 전도성이 우수한 Ag 또는 Au, Pt 등을 이용하고 있다. Ag의 경우 산화물기판 위에 증착하였을 경우 island 성장을 하고 이들의 합체는 전기적, 광학적 특성에 큰 영향을 미치게 된다. 본 연구에서는 DC-sputtering법으로 제조된 Ag/glass, Ag/Ta/glass 박막을 제조하고 Ta seeding이 Ag의 전기적, 광학적 성질에 미치는 영향을 관찰하였다. 박막의 표면 미세구조는 FE-SEM(Field Emission Scanning Electron Microscope)과 AFM(Atomic Force Microscope)으로, 표면저항은 4 point probe로 분석하였다. 광투과율은 UV-Vis spectroscopy와 FT-IR로 측정하였으며 측정파장범위는 각각 200~1100nm와 1400~2400nm 이다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.91-91
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• 2008

$SnO_2-B_2O_3-P_2O_5$ system were prepared by melt-quenching technique in the compositional series containing 50, 55 aod 60mol.% of $SnO_2$. A large glass-forming region was found at the phosphate side of the ternary system with homogeneous glasses containing up to 5-25mol.% of $B_2O_3$. For these glasses, thermal expansion coeffient($\alpha$), glass transition temperature(Tg), and glass softening temperature(Ts), were determined. The values a decrease with increasing $B_2O_3$ content, while Tg and Ts increased. The reason for the observed changes is local structure of the glasses. Local structure of the glasses was investigated by Raman and FT-IR measurements, suggesting that the number of bridging oxygens decreased whereas the non-bridging oxygen concentration increased with increasing $SnO_2$ content in the glasses.

• Korean Journal of Materials Research
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• v.12 no.7
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• pp.545-549
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• 2002

Potassium-Calcium-Phosphate glasses in range $XCaO\cdot(50-X)K_2O$ \cdot $50P_2$$O^{5}$were investigated. Glass transition temperature(Tg) of prepared glasses were below $520^{\circ}C$, thermal expansion coefficient from $270.3$\times$10^{7}$ to $604.5$\times$10^{7}$/$^{\circ}C$. The structure of XCaO.(50-X)$K_2$O\cdot$50P_2$$O^{5}$ glasses were examined by FT-IR spectroscopy indirectly. As CaO was increased, Ts, Tg, P-O-P bonding strength and chemical durability were increased. Glass surface change was observed with increasing dissolution time using bulk specimen, weight loss and pH change were measured as function of the dissolution time.

• The Korean Journal of Ceramics
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• v.5 no.1
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• pp.35-39
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• 1999

For many years, alkali activated blast furnace slag cement containing no ordinary portland cement has received much attention in the view of energy saving and its many excellent properties. We examined the structural change of slag glass which was activated by alkali metal compounds using IR spectroscopy. The properties of hydrated products and unhydrated slag grains was characterized by XRD and micro-conduction calorimeter. Ion concentration change in the liquid during the hydration of blast furnace slag was also studied to investigated the hydration mechanism.

• Journal of the Korean Ceramic Society
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• v.34 no.4
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• pp.357-367
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• 1997

A fast process for producing pure silica glasses with the reproducibility of 100% by means of sintering of silica aerogels was optimized. The density of silica glasses synthesized by heat-treating upto 110$0^{\circ}C$ with the heating rate of 0.1$^{\circ}C$/min was 2.197 g/㎤. Synthetic silica glasses(5 mm thickness) exhibited the transmittance of 92% in the near IR range as well as they had the excellent mechanical properties such as flexural strength of 162 MPa and hardness of 778 kg/$\textrm{mm}^2$.

• Elastomers and Composites
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• v.50 no.3
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• pp.210-216
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• 2015

Polyurethane modified silicone (PUMS) was synthesized from various molecular weights of polydimethylsiloxane (PDMS 2000, PDMS 6000, PDMS 20000), polypropyleneglycol with molecular weight of 3000 g/mol (PPG 3000) and 2,4-toluenediisocyanate (TDI) under tin catalyst. Their structures were confirmed by the measurement of FT-IR and $^1H-NMR$, and the thermal properties were studied from DSC and TGA. Glass transition temperature of PUMS exhibited exothermic peak at $-63{\sim}-69^{\circ}C$, and residual weight was 19~35% at $800^{\circ}C$.

• Journal of Conservation Science
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• v.35 no.4
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• pp.295-307
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• 2019

In the process of the conservation treatment of the glass eyes of the stone standing Maitreya of Daejosa temple, Buyeo (Treasure No. 217), a blackish material, expected to be the adhesive for fixing the glass eyes, was collected and analyzed. Infrared spectroscopy and pyrolysis/gas chromatography/mass spectrometry (pyrolysis/GC/MS) were employed to identify the organic material in the sample. The IR analysis revealed the presence of materials such as apatite or bone black. The pyrogram of the sample was similar to that of Asian lacquer, among traditional adhesives. In particular, the pyrolysis/GC/MS analysis with online methylation detected 1,2-dimethoxy-3-pentadecylbenzene, methyl 7-(2,3- dimethoxyphenyl) heptanoate, and methyl 8-(2,3-dimethoxyphenyl)octanoate. These are known to be the pyrolysis products of catechol and its oxidation product, which indicated the presence of Asian lacquer in the sample. X-ray diffraction, X-ray fluorescence, and thermal gravimetry analysis showed that the sample contained ca. 60% inorganic substances, including apatite. Radiocarbon dating of the sample suggested that the blackish material was applied between the late 13^th and early 15^th century, revealing some discrepancy with the art-historical manufacturing time of the Maitreya. From the above analysis, it was concluded that Asian lacquer and bone ash were used to attach the glass eyes by forming a thick blackish lacquer layer.

• Journal of the Korean Ceramic Society
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• v.29 no.9
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• pp.729-738
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• 1992

The glass formation and structural change with the glass compositions were investigated in the CaO-P2O5-SiO2 system with less than 40 wt% of P2O5. The glass formation range was determined by XRD, SEM and EDS techniques for water quenched specimens. The structural analyses were made for binary CaO-SiO2 glasses and ternary CaO-P2O5-SiO2 glasses by using FT-IR and Raman spectroscopy. The glass formation was affected by CaO/SiO2 mole ratio, P2O5 content and primary crystalline phase. The stable glass formation range was found when the transformed CaO/SiO2 mole ratio (new factor derived from structural changes) was in the range of 0.72~1.15 with less than 10 mol% of P2O5. The structural analyses of CaO-SiO2 glasses indicated that as the CaO/SiO2 ratio was increased, the nonbridging oxygens in the structural unit of the glasses were increased. With addition of P2O5 to CaO-SiO2 glasses, the P2O5 enhanced the polymerization of [SiO4] tetrahedra unit in CaO-SiO2 glasses, which contained a large portion of nonbridging oxygen. The phosphate eliminated nonbridging oxygens from silicate species, forcing polymerization of silicate structures and produced in [PO4] monomer in glasses. When added P2O5 was kept constant, the structural change with various CaO/SiO2 ratio was very similar to that of CaO-SiO2 glasses.

• Journal of the Korean Ceramic Society
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• v.47 no.2
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• pp.117-121
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• 2010

$SnO_2-(1-x)P_2O_5-xB_2O_3$ glass system were prepared by melt-quenching technique in the compositional series containing 50, 55 and 60 mol% of $SnO_2$. Local structure of the glasses was investigated by Raman and FT-IR measurements. A large glass-forming region was found at the phosphate side of the ternary system with homogeneous glasses containing up to 5~25 mol% of $B_2O_3$. According as content of $B_2O_3$ increases, theraml expansion coefficient of glass decreased but transition temperature and softening temperature increased. Because these phenomenon changed local structure of glass. According as content of $B_2O_3$ increases, quantity of bridging oxygen increased. Also, according as content of $SnO_2$ increases, confirmed that quantity of non-bridging oxygen increases.

• The Journal of Korea Robotics Society
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• v.12 no.3
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• pp.350-355
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• 2017

UWB (Ultra Wide Band) refers to a system with a bandwidth of over 500 MHz or a bandwidth of 20% of the center frequency. It is robust against channel fading and has a wide signal bandwidth. Using the IR-UWB based ranging system, it is possible to obtain decimeter-level ranging accuracy. Furthermore, IR-UWB system enables acquisition over glass or cement with high resolution. In recent years, IR-UWB-based ranging chipsets have become cheap and popular, and it has become possible to implement positioning systems of several tens of centimeters. The system can be configured as one-way ranging (OWR) positioning system for fast ranging and TWR (two-way ranging) positioning system for cheap and robust ranging. On the other hand, the ranging based positioning system has a limitation on the number of terminals for localization because it takes time to perform a communication procedure to perform ranging. To overcome this problem, code multiplexing and channel multiplexing are performed. However, errors occur in measurement due to interference between channels and code, multipath, and so on. The measurement filtering is used to reduce the measurement error, but more fundamentally, techniques for removing these measurements should be studied. First, the TWR based positioning was analyzed from a stochastic point of view and the effects of outlier measurements were summarized. The positioning algorithm for analytically identifying and removing single outlier is summarized and extended to three dimensions. Through the simulation, we have verified the algorithm to detect and remove single outliers.