• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2005년도 춘계학술발표대회 및 제8회 신소재 심포지엄 논문개요집
• /
• pp.35-35
• /
• 2005

• Journal of the Korean Wood Science and Technology
• /
• 제20권2호
• /
• pp.31-42
• /
• 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.

• 센서학회지
• /
• 제17권5호
• /
• pp.361-368
• /
• 2008

Nanosized $SnO_2$ particles were synthesized by homogeneous precipitation method using tin chloride ($SnCl_4{\cdot}5H_{2}O$) and urea ($CO(NH_2)_2$). The powders were heated at $500^{\circ}C$ and $600^{\circ}C$ for 2h. The crystal structure, microstructure, thermal behavior, specific surface area were analyzed using XRD, FE-SEM, TGA and BET, respectively. The initial resistance and the $H_2$ sensing properties were measured as a function of ${Sb_2}{O_3}$ and Pd doping concentrations. The resistance was decreased with the addition of ${Sb_2}{O_3}$ and the sensitivity for $H_2$ gas was increased with the addition of Pd. Thus, the optimum $H_2$ gas sensing property was obtained in the 0.25.mol% ${Sb_2}{O_3}$ and 1.w% added $SnO_2$ powders.

• Journal of Microbiology and Biotechnology
• /
• 제23권10호
• /
• pp.1422-1427
• /
• 2013

Scutellaria baicalensis (SB), a traditional herb with high pharmacological value, contains more than 10% flavone by weight. To improve the biological activity of flavones in SB, we aimed to enhance the bioconversion of baicalin (BG) to baicalein (B) and wogonoside (WG) to wogonin (W) in SB during fermentation using beta-glucuronidase produced from Lactobacillus brevis RO1. After activation, L. brevis RO1 was cultured in milk containing SB root extract with various carbon or nitrogen sources at $37^{\circ}C$ for 72 h. During fermentation, the growth patterns of L. brevis RO1 and changes in the flavone content were assessed using thin-layer chromatography and high-performance liquid chromatography. After 72 h of fermentation, the concentrations of B and W in the control group increased by only 0.15 and 0.12 mM, respectively, whereas they increased by 0.57 and 0.24 mM in the fish peptone group. The production of B and W was enhanced by the addition of 0.4% fish peptone, which not only improved the growth of L. brevis RO1 (p < 0.001) but also enhanced the bioconversion of flavones. In conclusion, the bioconversion of flavones in SB may provide a potential application for the enhancement of the functional components in SB.

• 한국재료학회지
• /
• 제21권10호
• /
• pp.542-545
• /
• 2011

Half-Heusler alloys are a potential thermoelectric material for use in high-temperature applications. In an attempt to produce half-Heusler thermoelectric materials with fine microstructures, TiCoSb was synthesized by the mechanical alloying of stoichiometric elemental powder compositions and then consolidated by vacuum hot pressing. The phase transformations during the mechanical alloying and hot consolidation process were investigated using XRD and SEM. A single-phase, half- Heusler allow was successfully produced by the mechanical alloying process, but a minor portion of the second phase of the CoSb formation was observed after the vacuum hot pressing. The thermoelectric properties as a function of the temperature were evaluated for the hot-pressed specimens. The Seebeck coefficients in the test range showed negative values, representing n-type conductivity, and the absolute value was found to be relatively low due to the existence of the second phase. It is shown that the electrical conductivity is relatively high and that the thermal conductivities are compatibly low in MA TiCoSb. The maximum ZT value was found to be relatively low in the test temperature range, possibly due to the lower Seebeck coefficient. The Hall mobility value appeared to be quite low, leading to the lower value of Seebeck coefficient. Thus, it is likely that the single phase produced by mechanical alloying process will show much higher ZT values after an excess Ti addition. It is also believed that further property enhancement can be obtained if appropriate dopants are selectively introduced into this MA TiCoSb System.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 하계학술대회 논문집
• /
• pp.134-134
• /
• 2009

In this work, we report that crystallization speed as well as the electrical and optical properties about the N-doped $Ge_2Sb_2Te_5$ thin films. The 200-nm-thick N-doped $Ge_2Sb_2Te_5$ thin film was deposited on p-type (100) Si and glass substrate by RF reactive sputtering at room temperature. The amorphous-to-crystalline phase transformation of N-doped $Ge_2Sb_2Te_5$ thin films investigated by X-ray diffraction (XRD). Changes in the optical transmittance of as-deposited and annealed films were measured using a UV-VIS-IR spectrophotometer and four-point probe was used to measure the sheet resistance of N-doped $Ge_2Sb_2Te_5$ thin films annealed at different temperature. In addition, the surface morphology and roughness of the films were observed by Atomic Force Microscope (AFM). The crystalline speed of amorphous N-doped $Ge_2Sb_2Te_5$ films were measured by using nano-pulse scanner with 658 nm laser diode (power : 1~17 mW, pulse duration: 10~460 ns). It was found that the crystalline speed of thin films are decreased by adding N and the crystalline temperature is higher. This means that N-dopant in $Ge_2Sb_2Te_5$ thin film plays a role to suppress amorphous-to-crystalline phase transformation.

• 한국재료학회지
• /
• 제32권3호
• /
• pp.146-152
• /
• 2022

One disadvantage of deep cycle flooded lead-acid batteries is increasing water loss caused by use of (+) Pb-Sb / (-) Pb-Sb alloy grid. Water loss is generated by the emission of hydrogen gas from the (-) electrode during battery charging. In this paper, we maintain cycle life aspect through the development of hybrid flooded lead-acid batteries to which a (+) Pb-Sb / (-) Pb-Ca grid is applied and deal with the improvement of water loss. The amount of water loss compared to that of the (-) Pb-Sb grid decreased when Ca was added to the (-) Pb grid. For the (-) Pb-Ca grid, it was confirmed that the time to reach 0.0 V, at which water decomposition occurs, was increased compared to that of the (-) Pb-Sb grid at the NPV (Negative Potential Voltage). In the cycle life test conducted with the BCI (Battery Council International) standard, compared to the (+) Pb-Ca grid, the (+) Pb-Sb grid increased the life cycle of the batteries and the (+) Pb-Ca grid showed an early end of life due to PbO corrosion layer generation, as determined through SEM / EDS and Tear Down analysis. In conclusion, by addition of Sb to (+) Pb grid and Ca to (-) Pb grid, we developed a hybrid flooded lead-acid battery that meets user requirements to improve water loss characteristics and preserve cycle life characteristics.

• 마이크로전자및패키징학회지
• /
• 제17권3호
• /
• pp.51-57
• /
• 2010

p형 $(Bi,Sb)_2Te_3$ 분말을 용해/분쇄법으로 제조하여 가압소결 후 가압소결조건에 따른 열전특성을 분석하였으며, 나노개재물로서 $ZrO_2$의 첨가에 따른 열전특성의 변화거동을 분석하였다. 가압소결온도를 $350^{\circ}C$에서 $550^{\circ}C$로 증가시킴에 따라 가압소결체의 Seebeck 계수가 275 ${\mu}V$/K에서 230 ${\mu}V$/K로 감소하였으며, 전기비저항이 6.68 $m{\Omega}m$-cm에서 1.86 $m{\Omega}$-cm로 감소하였다. 1 vol% 이상의 $ZrO_2$ 함량 증가에 따라 power factor가 계속 감소하는 거동으로부터 $(Bi,Sb)_2Te_3$ 가압소결체의 최대 power factor를 얻을 수 있는 $ZrO_2$ 나노개재물의 최적 함량은 1 vol% 미만으로 판단되었다.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제16권5호
• /
• pp.695-701
• /
• 2016

Be-doped GaSb layers were grown on highly mismatched semi-insulating GaAs substrate (001) with $2^{\circ}$ offcut towards <110> at low growth temperature, by molecular beam epitaxy (MBE). The influence of Be doping on the crystallographic quality, surface morphology, and electrical properties, was assessed by X-ray diffraction, Nomarski microscopy, and Hall effect measurements, respectively. Be impurities are well behaved acceptors with hole concentrations as high as $9{\times}10^{17}cm^{-3}$. In addition, the reduction of GaSb lattice parameter with Be doping was studied.

• 한국전기전자재료학회논문지
• /
• 제24권4호
• /
• pp.285-289
• /
• 2011

In this study, lead-free $(K_{0.5}Na_{0.5+X})(Nb_{0.96}Sb_{0.04})O_3+0.2mol%La_2O_3+1.2mol%$ $K_4CuNb_8O_{23}$ (X= 0~0.025) ceramics were fabricated by normal sintering method at $1060^{\circ}C$ for 5 h. Microstructures, piezoelectric and dielectric properties of specimens were investigated with special emphasis in the influence of Na excess addition. The grain size of specimen was slightly decreased with increasing Na content. In the 2 [mol%] Na excess addition of NKNS ceramics, density, electromechanical coupling factor, piezoelectric constant and electromechancal quality factor of specimen were found to reach the optimum values of 4.25 [$g/cm^3$], 0.4357, 154.43 [pC/N] and 580, respectively.