• 한국세라믹학회지
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• 제30권11호
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• pp.955-961
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• 1993

Sintering behavior and microstructure development in the system ZnO-Bi2O3-CoO-Zn7Sb2O12 with Zn7Sb2O12 content(0.1mol%~2mol%) were studied. The pyrochlore phase was formed by the reaction of the Zn7Sb2O12 with Bi2O3 phase during heating (below 90$0^{\circ}C$). The formation temperature of the liquid phase (Bi2O3) was dependent on the Zn7Sb2O12 contents (about 74$0^{\circ}C$ for Bi2O3/Zn7Sb2O12>1 by the eutectic melting in the ZnOBi2O3 system, and about 110$0^{\circ}C$ for Bi2O3/Zn7Sb2O12 1 by the decomposition of pyrochlore phase). Hence, sintering behavior and microstructure development were determined virtually by the Bi2O3/Zn7Sb2O12 ratio, which were promoted by liquid (Bi2O3) phase and retarded by the pyrochlore (or spinel) phase. The grain growth of ZnO during sintering was sluggish with increasing Zn7Sb2O12 contents.

• 한국재료학회지
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• 제15권2호
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• pp.93-96
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• 2005

The arc melting was employed to prepare undoped $CoSb_3$ compounds and their thermoelectric properties were investigated. Specimen annealed at $400^{\circ}C$ for 24 hrs showed sound microstructure. However, considerable voids and cracks were found after annealing at above $500^{\circ}C$. It seems to be attributed to the phase dissociation and thermal expansion due to phase transitions during annealing and cooling. Single phase $\delta-CoSb_3$ was successfully obtained by annealing at $400^{\circ}C$ for 24 hrs. In the case of increasing annealing temperature, phase decompositions occurred. Undoped $CoSb_3$ showed p-type conduction and intrinsic semiconducting behavior at all temperatures examined. Thermoelectric properties were remarkably improved by annealing and they were closely related to phase transitions.

• Fibers and Polymers
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• 제1권1호
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• pp.6-11
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• 2000

In the polycondensation reaction of polyethyleneterephthalate(PET), $Sb_2$$O_3$, can react effectively as a catalyst, if physically transformed. $Sb_2$$O_3$ powder is transformed into liquid solution by dissolving in ethylene glycol(EG). Homogeneous catalyst is made by mixing this liquid solution with glycols having different solubility. The efficient reaction of PET polymerization is expected by using homogeneous catalyst. PET was synthesized using homogeneous catalysts of 4 wt.% $Sb_2$$O_3$ solution dissolved in glycol[EG, 2,2-bis(4-(2-hydroxyethoxy)phenol)propane(BHPP), neopentyl glycol(NPO), and 1,3-propandiol(PD)]. PET using EG-BHPP($Sb_2$$O_3$) catalysts shows the highest I.V. within a reaction time of 120 min. In the p-d analysis, PET using EG-BHPP($Sb_2$$O_3$) catalysts has the fastest propagation rate and slowest degradation rate. EG-BHPP($Sb_2$$O_3$) catalysts are more efficient than EG($Sb_2$$O_3$) catalysts and $Sb_2$$O_3$ powder catalysts.

• 한국재료학회지
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• 제8권3호
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• pp.195-199
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• 1998

R.F. Magnetron Sputtering 법으로 Co를 base로 MnSbPt 합금박막의 최적 열처리 조건은 $300^{\circ}C$-4시간 이었으나, 종래의 MnSbPt 합금박막의 경우와 같이 수직자화막은 얻을 수 없었다. 보자력은 Co의 두께가 $250\AA$에서 최대를 나타냈으나 약 500 Oe이하로 실용적 측면에서 불충분 하였다. 진공중에서 $300^{\circ}C$ 4시간 열처리한 합금박막의 경우, 700nm의 입사파장에서 약 $0.78^{\circ}$에 이르는 Kerr 회전각을 보이므로 고보자력을 지닌 수직자화막을 제조할 수 있다면 우수한 차세대 고밀도 자기 기록매체로서 유망하다.

• 한국분말재료학회지
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• 제12권5호
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• pp.357-361
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• 2005

Fe-doped skutterudite $CoSb_3$ with a nominal composition of $Fe_{x}Co_{4-x}Sb_{12}(0\;{\le}\;x\;{\le}\;2.5)$ has been synthesized by mechanical alloying (MA) of elemental powders, followed by hot pressing. Phase transformations during mechanical alloying and hot pressing were systematically investigated using XRD. Single phase skutterudite was successfully produced by vacuum hot pressing using as-milled powders without subsequent annealing. However, second phase in the form of marcasite structure $FeSb_2$ was found to exist in case of $x\;{\ge}\;2$, suggesting the solubility limit of Fe with Co in this system. Thermoelectric properties as functions of temperature and Fe contents were evaluated for the hot pressed specimens. Fe substitution up to x=1.5 with Co in $Fe_{x}Co_{4-x}Sb_{12}$ appeared to increase thermoelectric figure of merit (ZT) and the maximum ZT was found to be 0.78 at 525K in this study.

• 대한금속재료학회지
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• 제56권11호
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• pp.822-828
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• 2018

P-type Ce/Yb-filled skutterudites were synthesized, and their charge transport and thermoelectric properties were investigated with partial double filling and charge compensation. In the case of $(Ce_{1-z}Yb_z)_{0.8}Fe_4Sb_{12}$ without Co substitution, the marcasite ($FeSb_2$) phase formed alongside the skutterudite phase, but the generation of the marcasite phase was inhibited by increasing Co concentration. The electrical conductivity decreased with increasing temperature, exhibiting degenerate semiconductor behavior. The Hall and Seebeck coefficients were positive, which confirmed that the specimens were p-type semiconductors with holes as the major carriers. The carrier concentration decreased as the concentration of Ce and Co increased, which led to decreased electrical conductivity and increased Seebeck coefficient. The thermal conductivity decreased due to a reduction in electronic thermal conductivity via Co substitution, and due to decreased lattice thermal conductivity via double filling of Ce and Yb. $(Ce_{0.25}Yb_{0.75})_{0.8}Fe_{3.5}Co_{0.5}Sb_{12}$ exhibited the greatest dimensionless figure of merit (ZT = 0.66 at 823 K).

• 한국전기전자재료학회논문지
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• 제28권12호
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• pp.852-856
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• 2015

In this study, we investigate the effect of high-energy ball milling on thermoelectric transport properties in double-filled $CoSb_3$ skutterudite ($In_{0.2}Yb_{0.1}Co_4Sb_{12}$). $In_{0.2}Yb_{0.1}Co_4Sb_{12}$ powders are milled using high-energy ball milling for different periods of time (0, 5, 10, and 20 min), and the milled powders are consolidated into bulk samples by spark plasma sintering. Microstructure analysis shows that the high-energy ball milled bulk samples are composed of nano- and micro-grains. Because the filling fractions are reduced in the bulk samples due to the kinetic energy of the high-energy ball milling, the carrier concentration of the bulk samples decreases with the ball milling time. Furthermore, the mobility of the bulk samples also decreases with the ball milling time due to enhanced grain boundary scattering of electrons. Reduction of electrical conductivity by ball milling has a decisive effect on thermoelectric transport in the bulk samples, power factor decreases with the ball milling time.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.688-689
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• 2006

Ni-doped $CoSb_3$ was prepared by the encapsulated induction melting and hot pressing, and its doping effects on the thermoelectric properties were investigated. Single phase $\delta-CoSb_3$ was successfully obtained by the subsequent heat treatment at 773K for 24 hours. Nickel atoms acted as electron donors by substituting cobalt atoms. Thermoelectric properties were remarkably improved by the appropriate doping.

• 생명과학회지
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• 제26권4호
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• pp.431-438
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• 2016

TRAIL은 정상세포에서는 세포독성을 나타내지 않는 반면, 암세포에서는 사멸을 유도하므로 항암제로 각광받고 있지만 많은 암세포에서 TRAIL에 저항성을 가지고 있는 것으로 알려져 있으므로 이를 극복해야하는 큰 어려움이 남아있다. 본 연구에서는 TRAIL에 저항성을 가지는 인간 방광암 세포주인 5637 세포를 이용하여 histone deacetylase 억제제인 sodium butyrate (SB)와 TRAIL을 혼합처리하였을 경우 유발되는 세포사멸 효과와 이와 관련된 분자생물학적 메카니즘을 연구하였다. 세포독성이 없는 조건의 TRAIL과 SB를 혼합처리 하였을 경우 SB 단독처리군 보다 세포사멸이 현저하게 증가하는 것으로 확인되었다. TRAIL과 SB의 혼합처리는 caspases (caspase-3, -8 and -9)의 활성화 및 PARP의 단편화를 유발하였다. 하지만 caspase 억제제에 의하여 TRAIL과 SB의 혼합처리에 의하여 유발되는 apoptosis가 현저하게 억제되는 것으로 나타났다. 또한 TRAIL과 SB의 혼합처리는 세포표면에 존재하는 DR5의 발현 증가 및 c-FLIP의 발현 감소를 유발하였으며, pro-apoptotic protein인 Bax와 세포질 cytochrome c의 발현 증가 및 anti- apoptotic protein인 Bcl-xL의 발현감소와 함께 tBid의 형성을 유발하였다. 이는 SB와 TRAIL의 혼합처리가 안전하고 선택적으로 TRAIL에 저항성을 가지는 방광암 세포에서 치료하는데 효과적인 전략임을 제시하는 결과이다.

• 한국주조공학회지
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• 제6권2호
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• pp.93-103
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• 1986

It is very important to obtain wear resistant ductile iron by adding more economical alloying elements. In this study, 10 heat of Mg-treated ductile iron were made according to Sb content (0-0.1% Sb). Each melt was tasted to 30 ${\o}test$ bars in $CO_2$ mold under the same condition and inspected wear characteristics, mechanical properties and microstructures. The results obtained from this study are as follows; 1. It is confirmed that Sb should be a simple and useful additive for improving wear resistance in ductile iron. 2. Hardness of ferrite and pearlite is improved with increasing Sb amount in ductile iron. 3. For ductile iron, the recommended ladle addition of Sb amount is to 0.02-0.03%. 4. Sb has adverse influence on spheroidizing of graphite if the amount is over 0.04%.