• Journal of the Korean Ceramic Society
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• v.37 no.4
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• pp.295-301
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• 2000

The effect of V2O5 addition on the low temperature sintering of Pb(Mn1/3Sb2/3)O3-PZT ceramics, which is known as a prominent material for piezoelectric transformer application was studied, and the densification behavior and piezoelectric characteristics of the samples as a function of heating rate were also examined. V2O5 led the system to liquid phase sintering by forming liquid phase during sintering, which accelerated densification through the particle rearrangement in the early stage of sintering. The liquid phase mostly existed at grain boundaries retarded the evaporation of PbO, while the densification temperature and the weight loss of V2O5-free samples were higher than those of samples with V2O5. Faster heating improved the densification of the samples regardless of V2O5 addition. The low temperature sintering at 100$0^{\circ}C$ was achieved in PMS-PZT ceramics with high density and reasonable dielectric and piezoelectric characteristics. This result revealed optimistic way to the development of multi-layered piezoelectric transformers.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.27 no.10
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• pp.630-634
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• 2014

$(Na_{0.525}K_{0.4425}Li_{0.0375})(Nb_{0.9975}Sb_{0.065}Ta_{0.0375})O_3+0.3 wt%CoO$ ceramics were fabricated as a function of CuO addition by traditional solid state sintering process in order to develop excellent lead-free piezoelectric ceramics composition. The addition of CuO in the LNKNTS composition ceramics can effectively enhance the densification of the ceramics, resulting in the oxygen vacancies as hardening effect. The excellent piezoelectric properties of electromechanical coupling factor($k{\small}_P$) of 0.378, piezoelectric constant($d_{33}$) of 152 pC/N were obtained from the 1.0 mol% CuO doped LNKNTS ceramics sintered at $1,020^{\circ}C$ for 3 h.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.7
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• pp.585-593
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• 2008

In this work, we report several experimental data capable of evaluating the phase transformation characteristics of GeSbTe pseudobinary thin films comprehensively utilized as phase change materials. The phase transformation of the GeSbTe thin films was confirmed by XRD measurement from amorphous to hexagonal structure via fee structure except for $Ge_8Sb_2Te_{11}$. In addition, X-ray photoelectron spectra analysis revealed to weaken Ge-Te bond for $Ge_2Sb_2Te_5$ and to strengthen the bonds of all elements for $Ge_8Sb_2Te_{11}$ during the amorphous to crystalline transition. The values of optical energy gap $(E_{OP})$ were around 0.71 and 0.50 eV and the slopes of absorption in extended region (B) were ${\sim}5.1{\times}10^5$ and ${\sim}10{\times}10^5cm^{-1}{\cdot}V^{-1}$ for the amorphous and fcc-crystalline structures, respectively. Finally, the kinetics of amorphous-to-crystalline phase change on the GeSbTe films was characterized using a nano-pulse scanner with 658-nm laser diode (power; $1{\sim}17$ mW, pulse duration; $10{\sim}460$ ns).

• Journal of the Korean Society for Heat Treatment
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• v.14 no.6
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• pp.330-335
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• 2001

Flake graphite cast irons with the high damping capacity have been used for the control of vibration and noise occurring in the members of various mechanical structures under vibrating conditions. However, the damping capacity which Is morphological characteristics of graphite is one of the important factors in reducing the vibration and noise, but hardly any work has deal with this problem. Therefore, the authors have examined the damping capacity of various cast irons with alloying elements and studied the influences of the matrix structures, mechanical properties and morphological characteristics of graphite. The main results obtained are as follows: Effects of Sb on the damping capacities and mechanical properties have been investigated in 3.6%C-0.2%Ni gray cast iron. At 0.02%Sb, specific damping capacity showed the maximum value, and decreased with further increase in Sb content. Mechanical properties showed opposite trend with the damping capacity. And then, effects of Ti on the damping capacities and mechanical properties have been investigated in 3.6%C-0.2%Ni-0.02%Sb gray cast iron. Specific damping capacity increased with increase in Ti content. Graphite length also showed same behavior. Tensile strength increased with Ti content due to refinement of pearlite. In the case of 0.14%Ti addition in 3.6%C-0.2%Ni-0.02%Sb cast iron, specific damping capacity and tensile strength was 36% and 25 $kgf/mm^2$ which are higher than 32% and 15 $kgf/mm^2$ at 3.6%C-0.2%Ni cast iron respectively.

• Korean Journal of Plant Resources
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• v.28 no.6
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• pp.704-709
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• 2015

Safflower (Carthamus tinctorius L.) seeds have long been clinically used in Korea to promote bone formation and prevent osteoporosis. In addition, the safflower buds (SB) were found to have more useful functional ingredients than safflower seed. Thus, we investigated the preventive effects of SB diet in ovariectomized (OVX) rats. The rats were divided into five groups; sham operated group, OVX alone group, OVX plus 17β-estradiol (E₂ 10 μg/kg, i.p.) and OVX plus SB diet feeding group (0.3% or 1%). Feeding of SB diet (0.3% or 3%) to OVX rats markedly increased trabecular formation in femur compared to OVX rats. Feeding of SB diet (0.3% or 3%) to OVX rats also decreased TRAP activity compared to OVX rats. These results suggest that SB diets have bone sparing effects by the decrease of osteoclast activity. We also observed that OVX rats fed with SB diet (0.3% or 3%) exhibited the decrease of calcium and phosphorus in serum compared to OVX-induced rats. Therefore, SB may be beneficial for the patients of osteoporosis, especially in postmenopausal women.

• Korean Journal of Materials Research
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• v.1 no.2
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• pp.65-70
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• 1991

The effect of inclusion particles on the microstructure development and electrical characteristics in the systems $ZnO-Bi_2O_3-CoO-Sb_2O_3\;and\;ZnO-Bi_2O_3-CoO-Sb_2O_3-Cr_2O_3 were investigated. The growth of ZnO grains, which was controlled by the spinel particles during sintering, decreased with increasing amount of spinel particles. Addition of $Cr_2O_3(0.5mol\%) increased the breakdown voltage without affecting the non-linear characteristics. The calculated barrier voltage of the $ZnO-Bi_2O_3-CoO-Sb_2O_3\;-and\;ZnO-Bi_2O_3-CoO-Sb_2O_3-Cr_2O_3$ systems were about 3.1V and 2.9V, respectively.

• Applied Chemistry for Engineering
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• v.33 no.1
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• pp.64-70
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• 2022

In this study, an experiment was performed by adding Sb during NH3-selective catalytic reduction (NH₃-SCR) while varying calcination temperatures from 400 to 700 ℃ to improve the low temperature denitrification efficiency of VWTi catalyst. As a result, VWSbTi(500) and VWSbTi(600) catalysts corresponding to Sb calcination temperatures of 500~600 ℃ showed the best denitrification performance at low temperatures below 300 ℃. BET, XRD, Raman, XPS, H₂-TPR, and NH₃-TPD analyses were performed In order to confirm physicochemical properties according to the calcination temperature. In the case of VWSbTi(500) and VWSbTi(600), an acid site increased with the generation of W=O species, and superb activity at low temperatures was exhibited due to the excellent redox characteristics and increase in electron density of tungsten. Furthermore, in the case of VWSbTi(700), as the crystalline V₂O₅ structure was formed, the denitrification efficiency decreased. Thus the optimum calcination temperature during Sb addition process was confirmed.

• Korean Journal of Acupuncture
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• v.29 no.3
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• pp.406-420
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• 2012

Objectives : Scutellaria barbata has been widely used in oriental medicine used for treatment of acute and chronic inflammatory diseases. In this study, to investigate the protective effect of Scutellaria barbata on type I allergic response, we determined whether Scutellaria barbata inhibits early or late allergic responses. Methods : To assess the effect of Scutellaria barbata Pharmacopuncture Extract(SB) in RBL-2H3 cells, we investigated the levels of the markers of degranulation such as ${\beta}$-hexosaminidase and histamine, inflammatory mediator such as IL-4, TNF-${\alpha}$, PGE2 and cysLT, and mRNA expression of cytokines and enzymes. In addition, we determined the levels of intracellular ROS by DCFH-DA assay and the free radical scavenging activity by DPPH method. Results : We found that SB suppressed the release of ${\beta}$-hexosaminidase and histamine and the production of IL-4, TNF-${\alpha}$, PGE2 and cysLT in RBL-2H3 by the antigen stimulation. SB also significantly inhibited the enzyme mRNA expressions, such as HDC2, COX-1, COX-2, 5-LOX and iNOS2, along with reduced cytokine mRNA expressions, such as IL-$1{\beta}$, IL-2, IL-3, IL-4, IL-5, IL-6, IL-13, TNF-${\alpha}$ and GM-CSF in RBL-2H3. In addition, SB suppressed the levels of intracellular ROS. Conclusions : Our results indicate that SB protects against type I allergic response and exert an anti-inflammatory effect through the inhibition of degranulation, inflammatory mediator release and mRNA expression of cytokines and enzymes.

• Journal of the Korean Ceramic Society
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• v.44 no.8
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• pp.419-423
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• 2007

The behavior of oxygen gas participating in fining was observed in CRT (Cathode Ray Tube) glass melts doped with $Sb_2O_5\;or\;CeO_2$ by means of a yttria-stabilized zirconia (YSZ) electrode. The temperature dependence of the oxygen equilibrium pressure ($P_{o2}$) or the activity in both melts showed typical behavior corresponding to a theoretical redox reaction. In other words, the $P_{o2}$ value of melts with $CeO_2$ was lower than that of melts with $Sb_2O_5$ above $1250^{\circ}C$. The result implies that $Sb_2O_5$, is more efficient as a fining agent compared to $CeO_2$. On the other hand, melts from a batch containing $Sb_2O_5\;and\;KNO_3$ showed much higher $P_{o2}$ values compared to melts without $KNO_3$ above $1350^{\circ}C$. It is suggested that the addition of $KNO_3$ to CRT glass batch contributes partly to the first fining of the melts.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.185-189
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• 2000

ZnO varistor has many merits as compared with SiC varistor. But, because of leakage current and non-linear coefficient, it has unstable function properties. For the purpose of improvement of ZnO varistor properties, ZnO varistor is studied according to sintering condition and mixing condition. ZnO varistor, $ZnO-Bi_2O_2-Y_2O_3-MnO-Cr_2O_3-Sb_2O_3$ series, is fabricated with $Sb_2O_3$ mol ratio(0.5-4[mol%]) and sintered at $1250[^{\circ}C]$ In accordance with $Sb_2O_3$ mol ratio and sintering temperature, grain size and non-linear coefficient are measured. The specimen, $Sb_2O_3$ mol ratio is 1[mol%], has small grain size. It has best properties because of its liquid phase shape. When $Sb_2O_3$ mol ratio is 1[mol%], grain size is decreased.