• Korean Journal of Materials Research
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• v.33 no.10
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• pp.414-421
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• 2023

Infrared radiation (IR) refers to the region of the electromagnetic radiation spectrum where wavelengths range from about 700 nm to 1 mm. Any object with a temperature above absolute zero (0 K) radiates in the infrared region, and a material that transmits radiant energy in the range of 0.74 to 1.4 um is referred to as a near-infrared optical material. Germanate-based glass is attracting attention as a glass material for infrared optical lenses because of its simple manufacturing process. With the recent development of the glass molding press (GMP) process, thermal imaging cameras using oxide-based infrared lenses can be easily mass-produced, expanding their uses. To improve the mechanical and optical properties of commercial materials consisting of ternary systems, germanate-based heavy metal oxide glasses were prepared using a melt-cooling method. The fabricated samples were evaluated for thermal, structural, and optical properties using DSC, XRD, and XRF, respectively. To derive a composition with high glass stability for lens applications, ZnO and Sb₂O₃ were substituted at 0, 1, 2, 3, and 4 mol%. The glass with 1 mol% added Sb₂O₃ was confirmed to have the optimal conditions, with an optical transmittance of 80 % or more, a glass transition temperature of 660 ℃, a refractive index of 1.810, and a Vickers hardness of 558. The possibility of its application as an alternative infrared lens material to existing commercial materials capable of GMP processing was confirmed.

• Imaging Science in Dentistry
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• v.48 no.4
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• pp.277-281
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• 2018

Purpose: This study was performed to investigate the relationship between sleep bruxism(SB) and pulpal calcifications in young women. Materials and Methods: A total of 100 female participants between 20 and 31 years of age who were referred to our radiology clinic for a dental check-up, including 59 SB and 41 non-SB patients, were sampled for the analysis. SB was diagnosed based on the American Academy of Sleep Medicine criteria. All teeth were evaluated on digital panoramic radiographs to detect pulpal calcifications, except third molars, teeth with root canal treatment, and teeth with root resorption. Binary logistic regression analysis was used to determine the risk factors for pulpal calcifications. The Spearman correlation coefficient was applied and the Pearson chi-square test was used for categorical variables. To test intra-examiner reproducibility, Cohen kappa analysis was applied. P values <.05 were considered to indicate statistical significance. Results: A total of 2800 teeth were evaluated (1652 teeth from SB patients and 1148 from non-SB patients), and 61% of patients had at least 1 dental pulpal calcification. No statistically significant relationship was found between SB and pulpal calcifications (P>0.05). In SB patients, the total number of pulpal calcifications was 129, while in non-SB patients, it was 84. Binary logistic analysis showed that SB was not a risk factor for the presence of pulpal calcifications(odds ratio, 1.19; 95% CI, 0.52-2.69, P>.05). Conclusion: No relationship was found between SB and pulpal calcifications.

• Korean Journal of Materials Research
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• v.14 no.2
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• pp.115-120
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• 2004

Perovskite barium-strontium titanate, $(Ba, Sr)TiO_3$ was prepared and effects of $Sb_2$O$_3$ additives on its PTCR properties were investigated. $The (Ba,Sr)TiO_3$ with 0.05～0.25 mol% $Sb_2$$O_3$ showed semiconducting PTCR behavior and anomalous grain growth was also observed when it was sintered above $1330^{\circ}C$. It was considered that charge compensation by doping 8b203 as well as abnormal grain growth by sintering lead to resistivity reduction from insulating to semiconducting transition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.280-280
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• 2007

Lead oxide-based ferroelectrics are the most widely used materials for piezoelectric actuators, sensors and transducers due to their excellent piezoelectric properties. Considering lead toxicity, there is great interest in developing lead-free piezoelectric materials, which are biocompatible and environmentally friendlier. Recently alkali oxide materials, including sodium - potassium niobate (NKN), have been given attention in view of their ultrasonic application and also as promising candidates for piezoelectric lead-free system. However, it is difficult to sinter such NKN-based materials via conventional sintering process. In this reason, many researchers have investigated hot press, hot isostatic press or spark-plasma sintering of NKN-based ceramics. In this study, as candidates for lead-free piezoelectric materials, dense (Na,K,Li)(Nb,Sb)$O_3$ systems were developed by conventional sintering process. The microstructures and piezoelectric properties of the (Na,K,Li)(Nb,Sb)$O_3$ systems were investigated as a function of variable compositions. The excellent piezoelectric and electromechanical properties indicate that this system is potentially good candidate as lead-free material for a wide range of electro-mechanical transducer applications.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.449-452
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• 2009

In order to improve incombustibility of EPDM(Ethylene propylene diene monomer)-based rubber, inorganic materials as $Al(OH)_3$ and $Sb_2O_3$ were added. The mechanical and thermal properties have been measured for vulcanized rubber loaded with different concentrations of $Al(OH)_3$ and $Sb_2O_3$. As inorganic material contents increases from 5phr to 30phr, the specific gravity and hardness increase while elongation at break decreases. This study performed incombustibility test and thermal analysis through TGA(Thermogravimetric Analyzer). As a results, incombustible and thermal properties of EPDM-based rubber were improved as $Al(OH)_3$ and $Sb_2O_3$ contents increase.

• Korean Journal of Materials Research
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• v.24 no.3
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• pp.145-151
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• 2014

Solution-based Sb-doped $SnO_2$ (ATO) transparent conductive oxides using a low-temperature process were fabricated by an electrospray technique followed by spin coating. We demonstrated their structural, chemical, morphological, electrical, and optical properties by means of X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, atomic force microscopy, Hall effect measurement system, and UV-Vis spectrophotometry. In order to investigate optimum electrical and optical properties at low-temperature annealing, we systemically coated two layer, four layer, and six layers of ATO sol-solution using spin-coating on the electrosprayed ATO thin films. The resistivity and optical transmittance of the ATO thin films decreased as the thickness of ATO sol-layer increased. Then, the ATO thin films with two sol-layers exhibited superb figure of merit compared to the other samples. The performance improvement in a low temperature process ($300^{\circ}C$) can be explained by the effect of enhanced carrier concentration due to the improved densification of the ATO thin films causing the optimum sol-layer coating. Therefore, the solution-based ATO thin films prepared at $300^{\circ}C$C exhibited the superb electrical (${\sim}7.25{\times}10^{-3}{\Omega}{\cdot}cm$) and optical transmittance (~83.1 %) performances.

• Journal of the Korean Vacuum Society
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• v.22 no.6
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• pp.327-334
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• 2013

Long-wave infrared detectors using the type-II InAs/GaSb strained superlattice (T2SL) material system with the nBn structure were designed and fabricated. The band gap energy of the T2SL material was calculated as a function of the thickness of the InAs and GaSb layers by the Kronig-Penney model. Growth of the barrier material ($Al_{0.2}Ga_{0.8}Sb$) incorporated Te doping to reduce the dark current. The full width at half maximum (FWHM) of the $1^{st}$ satellite superlattice peak from the X-ray diffraction was around 45 arcsec. The cutoff wavelength of the fabricated device was ${\sim}10.2{\mu}m$ (0.12 eV) at 80 K while under an applied bias of -1.4 V. The measured activation energy of the device was ~0.128 eV. The dark current density was shown to be $1.0{\times}10^{-2}A/cm^2$ at 80 K and with a bias -1.5 V. The responsivity was 0.58 A/W at $7.5{\mu}m$ at 80 K and with a bias of -1.5 V.

• Journal of the Semiconductor & Display Technology
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• v.8 no.3
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• pp.13-17
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• 2009

we have studied characterization of microbolometer based on the co-sputtered silicon-antimony ($Si_{1-x}Sb_x$) thin film for infrared microbolometer. We have investigated the resistivity and the temperature coefficient of resistance (TCR) with annealing. We deposited the films using co-sputtering method at $200^{\circ}C$ in the Ar environment. The Sb concentration has been adjusted by applying variable DC power from Sb targets. TCR of deposited $Si_{1-x}Sb_x$ films have been measured the range of -2.3~-2.8%/K. The resistivity of the film is low but TCR is higher than the other bolometer materials. Resistivity of the films has not been affected hugely according to the low annealing temperature however the resistivity has been dramatically decreased over $250^{\circ}C$. It is caused of a phase change due to the rearrangement of Si and Sb atoms during crystallization process of the films.

• Journal of the Korean Wood Science and Technology
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• v.20 no.2
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• pp.31-42
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• 1992

In this study, the relative effectiveness of antimony trioxide-containing coat on fire retardancy of plywood, particleboard and medium density fiberboard was investigated and compared through ISO ignition test and inclined panel test with non-coated ones. The results obtained were summarized as fallows: Any treated materials was not ignited in inclined panel test with 5 minutes, but only particleboard among treated ones burned in ISO ignition test with fairly delayed time. The weight loss rate of plywood decreased with the increased addition level of fire-retardant and the least values were obtained in particleboard and MDF at addition level of 7% and 5% respectively. Carbonized area of wood based materials decreased with the increased addition level of fire retardant. The temperatures of back in plywood, particleboard treated with fire-retard ant coat containing 7% $Sb_2O_3$ showed the lowest but MDF did not show any effectiveness with the increased addition level. The first flash time of plywood treated with fire retardant coat containing 9% $Sb_2O_3$, MDF and particleboard treated with fire retardant coat containing 7% $Sb_2O_3$ were 257sec., 286.4sec., 165.4sec. respectively.

• Fisheries and Aquatic Sciences
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• v.23 no.1
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• pp.2.1-2.6
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• 2020

Background: As the cost of fishmeal continues to rise, there will be a need to optimize the diet by minimizing dietary fishmeal inclusion in aquafeed. In this study, a 7-week experiment was conducted to evaluate soybean meal, fermented soybean meal (soytide), and sesame meal as fishmeal replacers in whiteleg shrimp, Litopenaeus vannamei. Methods: A 30%-based fishmeal diet was considered as control (CON), six other diets were prepared by replacing 20% or 40% of fishmeal with soybean meal (SB₂₀ and SB₄₀), fermented soybean meal (ST₂₀ and ST₄₀), or sesame meal (SM₂₀ and SM₄₀) from the CON diet. Twenty shrimp with average initial weight of 0.65 ± 0.05 g (mean ± SD) were randomly distributed into 21 tanks (45 L) and fed four times a day. Water temperature was controlled at 28 ± 1 ℃ and aeration was provided by air stones. Results: Weight gain, specific growth rate, feed efficiency, and protein efficiency ratio of shrimp fed CON showed no significant differences compared to shrimp fed all the other diets. However, growth performance of shrimp fed ST₂₀ diet was significantly higher than those of shrimp fed the SM₂₀ and SM₄₀ diets (P < 0.05). Superoxide dismutase activity (SOD) of shrimp fed CON, ST₂₀, and ST₄₀ diets was significantly higher than those of shrimp fed the SB₄₀ and SM₄₀ diets. But there were no significant differences among shrimp fed CON, SB₂₀, ST₂₀, ST₄₀, and SM₂₀ diets. Also, lysozyme activity of shrimp fed ST₂₀ diet was significantly higher than those of shrimp fed the SB₄₀ and SM₄₀ diets. Although, lysozyme activity of shrimp fed the CON diet was not significantly different compared to shrimp fed all the other experimental diets. Conclusions: Therefore, SB, ST, and SM could replace 40% of fishmeal based on growth performance and lysozyme. According to the SOD activity, SB and SM could replace 20% of fishmeal and ST could replace 40% of fishmeal in juvenile whiteleg shrimp Litopenaeus vannamei.