• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.60-63
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• 1997

Dieletric ailed piezoelectric properties of Pb[$Zr_{0.45}$/ $Ti_{0.5-x}$/L $u_{x}$ (M $n_{1}$3//S $b_{2}$3)$_{0.05}$] $O_3$(0$\leq$x $\leq$0.03) were investigated. The partial substitution of $Ti^{4+}$ by a L $u^{3+}$ permitted improvement of the piezoelectric constant( $d_{33}$ ), electromechanical coupling factor ( $k_{p}$ ) and dielectric constant($\varepsilon$$_{33}$ /Sup T/). The dielectric loss(tan $\delta$ ) increased and mechanical quality factor(Qm) decreased with an increase of x were observed. A new piezoelectric material for actuator application was developed at x=0.02 with $d_{33}$ =370$\times$10$^{-2}$ /C/N, $k_{p}$ =58.5%, $\varepsilon$$_{33}$ $^{T}$ =1321, $Q_{m}$ =714 and tan $\delta$ =0.98%.%..%.%.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.1
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• pp.25-30
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• 2007

In this paper, lead-free [$Li_{0.04}(Na_{y}K_{1-y})_{0.96}](Nb_{0.86}Ta_{0.1}Sb_{0.04})O_{3}$ (y=0.4 - 0.58) ceramics were manufactured using conventional miked oxide method for acoustic emission(AE) sensor application and their dielectric and piezoelectric properties were investigated with the variations of Na/K ratio. The samples in the composition Na/K=54/46 exhibited excellent electrical properties of $d_{33}=300$ PC/N and kp=0.49. Taking into consideration above piezoelectric properties, it can be concluded that the [$Li_{0.04}(Na_{y}K_{1-y})_{0.96}](Nb_{0.86}Ta_{0.1}Sb_{0.04})O_{3}$ system ceramics are the promising lead-free materials capable of substituting PZT system ceramics.

• Korean Journal of Materials Research
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• v.15 no.2
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• pp.89-92
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• 2005

The induction melting was employed to prepare Nb-doped $CoSb_3$ skutterudites and their thermoelectric properties were investigated. Single phase $\delta-CoSb_3$ was successfully obtained by induction melting and subsequent annealing at $400^{\circ}C$ for 2 hrs in vacuum. The positive signs of Seebeck coefficients for all the specimens revealed that Nb atoms acted as p-type dopants by substituting Co atoms. Electrical conductivity decreased and then increased with increasing temperature, indicating mixed conduction behavior. Electrical conductivity increased by Nb doping, and it was saturated at high temperature. Maximum value of the thermoelectric power factor was shifted to higher temperature with increasing the amount of Nb doping, mainly originated from the high Seebeck coefficient around mixed conduction temperature and high electrical conductivity.

• Natural Product Sciences
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• v.16 no.3
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• pp.192-197
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• 2010

The seeds of Raphanus sativus L. (RSL) and Phaseolus calcaratus Roxburgh (PHCR), the root of Scutellaria baicalensis (SB), and the flower of Lonicera japonica (LJ) have been traditionally used as herbal medicines for anti-inflammation. Unlike the SB and LJ, little information is available for the scientific bases that show the anti-inflammatory mechanisms of RSL and PHCR. In this study, we prepared boiled water extracts from the medicines and determined their potentials in inhibiting nitric oxide (NO) production, cyclooxygenase-2 (COX-2) expression, and tumor necrosis factor (TNF)-$\alpha$ and interleukin (IL)-6 secretion in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. The effects of the medicines on serum IgE levels in ovalbumin (OVA)-administrated mice were also studied. The medicines inhibited production of TNF-$\alpha$ and IL-6, and COX-2 expression in LPSstimulated macrophages. Especially, PHCR water extract showed more potent inhibition on TNF-$\alpha$ production than SB and LJ extracts, but RSL extract did not exert these effects. Similar to the cases of SB and LJ, PHCR extract prevented the phosphorylation of $I{\kappa}B{\alpha}$ and c-Jun, and the activation of NF-${\kappa}B$-DNA binding. Further, oral supplementation of PHCR extract attenuated significantly serum levels of total and OVA-specific IgE in OVAtreated animals. These results suggest a possibility that PHCR water extract can be used for the treatment of inflammatory and allergic diseases.

• Journal of the Korean Ceramic Society
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• v.45 no.6
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• pp.363-367
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• 2008

Lead-free $(K_{0.44}Na_{0.52})(Nb_{0.86}Ta_{0.10})-0.04LiSbO_3$ piezoelectric ceramics have been synthesized by conventional sintering process and then investigated on the sintering and piezoelectric properties by high energy ball milling (HEBM) treatment. The powders milled for different time are characterized by XRD, FE-SEM. The powders are pressed into a pellet and sintered. It is found that the piezoelectric properties of sintered specimens are strongly dependent on the milling time. The piezoelectric properties are enhanced by high energy ball milling treatment. The planer electromechanical coupling factor ($k_p$) and piezoelectric constant ($d_{33}$) of a specimen sintered at $1050^{\circ}C$ are 0.44 and 267 pC/N, respectively.

• Corrosion Science and Technology
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• v.9 no.6
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• pp.259-264
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• 2010

In continuous hot dip galvanizing process, oxide formation on steel surface has an influence on Zn wetting. High strength automotive steel contains high amount of Si and Mn, where Si-Mn composite oxides such as $Mn_2SiO_4$ or $MnSiO_3$ covers the surface after annealing. Zn wetting depends on how the aluminothermia reaction can reduce the Mn-Si composite oxides and then form inhibition layer such as $Fe_2Al_5$ on the steel surface. The outward diffusion of metallic ions such as $Mn^{2+}$, $Si^{2+}$ in the steel matrix is very important factor for the formation of the surface oxides on the steel surface. The surface state and grain boundaries provide an important role for the diffusion and the surface oxide reactions. Some elements such as P, Sb, and B have a strong affinity for the interface precipitation, and it influence the diffusivity of metallic ions on grain boundaries. B oxide forms very rapildly on the steel surface during the annealing, and this promote complex oxides with $SiO_2$ or MnO. P has inter-reacted with other elements on the grain boundaries and influence the diffusion through on them. Small addition of Sb could suppress the decarburization from steel surface and retards the formation of internal and external selective oxides on the steel surface. Interface control by the trace elements such as Sb could be available to improve the Zn wettability during the hot dip galvanizing.

• Proceedings of the KIEE Conference
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• 1985.07a
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• pp.191-193
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• 1985

Reaction temperature md piezoelectric properties of Pb(Mn1/3 Sb2/3)0.08 Ti0.495 Zr0.425 $O_3$ ceramics by hydrothermal synthesis method have been investigated. Sintering density and dielectric constant of sample increased with increasing of hydrothermal reaction temperature, while decreased rapidly above $240^{\circ}C$. Electromechanical coupling factor kp was almost constant at the reaction temperature $160^{\circ}-240^{\circ}C$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.161-164
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• 2001

In this paper, we investigated the dielectric and piezoelectric properties of Pb(Sb, Nb)O$_3$-Pb(Zr, Ti)O$_3$ ceramic(PSN) for piezoelectric transformer and actuator etc. Effect of MnO$_2$ addition on the PSN ceramic was investigated. Anisotropic properties of electromechanical coupling factor and piezoelectric properties proved to be varied with amount of MnO$_2$ impurity and sintering temperature. The electromechanical coupling factor k$_{p}$ of 0.38 and the mechanical quality factor Q$_{m}$ of 1944 were obtained from the specimen with 0.4 wt% MnO$_2$ sintered at 115$0^{\circ}C$ addition. Experimental results indicated that the PSN ceramic with MnO$_2$ impurity can be effectively used for piezoelectric transformer and actuator.tor.

• Journal of Acupuncture Research
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• v.29 no.6
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• pp.35-45
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• 2012

Objectives : This study was designed to investigate Effects of Sujeom powder(SJP) pharmacopuncture Injected at Jung-wan($CV_{12}$) in rats with caerulein-induced acute pancreatitis(AP). Methods : We examined changes of organ weight, histology, immunohistochemistry and gene expression of cycolooxygenase 2(COX-2) in the pancreas. Twenty adult male Sprague-Dawley rats were divided into four groups as follow: normal(Nor), caerulein-induced(Con), caerulein+SJP pharmacopuncture 0.2mL injected at Jung-wan($CV_{12}$)(SA), and caerulein+SJP pharmacopuncture 0.8 mL injected at Jung-wan($CV_{12}$)(SB) groups. Pancreatic tissues of rats from all groups were removed for histological observation and light microscopic examination. Interleukin-6(IL-6) levels were determined spectrophotometrically. Results : The ratio of pancreas/body weights was significantly(p<0.05) increased in the Con, the SA and the SB compared with the Nor, but was slightly decreased in the SA and in the SB groups compared with the Con. Caerulein administration has significantly(p<0.05) increased in the levels of amylase, but the SA, the SB significantly(p<0.05) decreased in the levels of these enzyme. The levels of amylase were increased significantly with caerulein administration, but were inhibited significantly in the SA and in the SB groups. Interleukin-6(IL-6) levels were significantly(p<005) increased in all groups compared with the Nor, especially in the SB. were significantly increased. The levels of Tumor necrosis factor(TNF)-${\alpha}$ levels were significantly increased in all groups compared with the Nor. In the conclusion, the datum of IL-6 and TNF-${\alpha}$ are suggested that the inflamation was still existed actively at a point of measurement(24 hours later). The COX-2 positive materials are observed in the pancreas from the Con, but these positive materials are decreased in the SJP pharmacopuncture at Jung-wan($CV_{12}$) treatment group. Conclusion : SJP pharmacopuncture injected at Jung-wan($CV_{12}$) is potentially capable of limiting pancreatic damage during AP by restoring the fine structure of acinar cells and tissues. Therefore we can say that SJP pharmacopuncture Injected at Jung-wan($CV_{12}$) may have beneficial effects in the treatment of caerulein-induded AP. Further studies about the adequate amount of the SJP pharmacopuncture and about more effective route of administration is still required.

• Applied Microscopy
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• v.34 no.4
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• pp.255-264
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• 2004

The three-dimensional (3D) structure of an inorganic crystal, $SmZn_{0.67}Sb_2$ (space group P4/nmm, $a=4.26{\AA}\;and\;c=10.37{\AA}$) was solved by electron crystallography. High resolution electron microscopy (HREM) images from 3 different major zone axes and selected-area electron diffraction patterns from 16 different zone axes were combined to obtain a 3D information. A crystallographic image processing (CIP) of HREM images was used for more accurate determination of the crystal structure. As a result of this electron crystallography, average phase errors (${\Phi}_{res}$) of [001], [100] and [110] HREM images are $17.0^{\circ},\;8.3^{\circ}\;and\;21.9^{\circ}$, respectively. Xray crystallography of $SmZn_{0.67}Sb_2$ has attempted to compare accuracy of the structure determination by electron crystallography, which resulted in the cell parameters of $a=4.2976(6){\AA}\;and\;c=10.287(2){\AA}$, and the R-factor ($R_{sym}$) of 4.16%.