http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Thermoelectric Properties of Bi-doped Mg2Si1−xSnx Prepared by Mechanical Alloying
유신욱,김일호,최순목,서원선 한국물리학회 2013 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.63 No.11
Bi-doped Mg2Si1−xSnx solid solutions were prepared by mechanical alloying and hot pressing. The lattice constant increased and the electrical conduction behavior changed from n-type to p-typewith increasing Sn content. The electrical conductivity increased with increasing Sn content at aspecific temperature. Bi-doped Mg2Si1−xSnx solid solutions showed n-type conduction, and thecarrier concentration was increased because of doped Bi acting as donors. The absolute value ofthe Seebeck coefficient decreased with increasing temperature. The lowest thermal conductivity of1.3 - 1.5 W/mK was obtained by Bi doping. Mg2Si0.7Sn0.3:Bi0.01 exhibited a maximum figure ofmerit (ZT) of 0.65 at 823 K.
밀폐유도용해로 제조된 2원계 Skutterudite CoSb<sub>3</sub>의 열전특성
유신욱,정재용,어순철,김일호,You, Sin-Wook,Jung, Jae-Yong,Ur, Soon-Chul,Kim, Il-Ho 한국재료학회 2006 한국재료학회지 Vol.16 No.5
Binary skutterudite $CoSb_3$ compounds were prepared by the encapsulated induction melting (EIM) process, and their thermoelectric, microstructural and mechanical properties were examined. Single-phase ${\delta}-CoSb_3$ was successfully produced by the EIM and subsequent heat treatment at 773 K-873 K for 24 hours in vacuum. Seebeck coefficient increased with increasing heat treatment temperature up to 673 K, showing the positive signs in the range of measuring temperature. However, the samples heat-treated at 773 K-873 K showed negative Seebeck coefficient from room temperature to 400 K, while it showed positive signs above 400 K. Electrical resistivity decreased with increasing temperature, showing typical semiconducting conductivity. Thermal conductivity decreased drastically with increasing heat-treatment temperature. This is closely related with the phase transition to ${\delta}-CoSb_3$.
Thermoelectric properties of Sb-doped Mg2Si1-xSnx prepared by mechanical alloying and hot pressing
유신욱,김일호,최순목,서원선 한양대학교 세라믹연구소 2014 Journal of Ceramic Processing Research Vol.15 No.6
Sb-doped Mg2Si1-xSnx solid solutions were prepared by mechanical alloying and hot pressing. The electrical conduction behavior changed from n-type to p-type with increasing Sn content. The electrical conductivity increased with an increase in Sn content at specific temperatures. Sb-doped Mg2Si1-xSnx solid solutions showed n-type conduction, and the carrier concentration was increased by the doped Sb acting as donors. The absolute value of the Seebeck coefficient decreased with increasing temperature. The lowest thermal conductivity of 1.3 W/mK was obtained by Sb doping. Mg2Si0.7Sn0.3 : Sb0.01 exhibited a maximum ZT of 0.56 at 723 K.
Thermoelectric Properties of Mg2Si0.7Ge0.3Bim Prepared Using a Solid-state Reaction
유신욱,Dong-Kil Shin,김일호 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.1
Mg2Si0.7Ge0.3Bim (m = 0 − 0.03) solid solutions were synthesized using a solid-state reactionand consolidated by hot pressing. All specimens showed n-type conduction, and the carrier concentrationincreased from 4.0 × 1017 to 2.1 × 1020 cm−3 with increasing Bi-doping content; theelectrical conductivity thereby increased from 7.3 × 102 to 7.0 × 104 Sm−1 at room temperature. The electrical conductivity of the undoped specimen increased with increasing temperature, andthe specimen behaved similar to a non-degenerate semiconductor. The absolute value of the Seebeckcoefficient of the undoped specimen was very high at low temperature, but it decreased withincreasing temperature. Bi-doped Mg2Si0.7Ge0.3 showed a Seebeck coefficient ranging from −235 to−197 μVK−1 at 823 K. The power factor significantly increased with Bi doping and increased withincreasing temperature; it were also improved by around 10 times at 823 K. The lowest thermalconductivity was 2.2 Wm−1K−1 for Mg2Si0.7Ge0.3Bi0.02 at 823 K, and the maximum ZT value of0.79 was obtained for Mg2Si0.7Ge0.3Bi0.02 at 823 K.
아크용해법으로 제조된 Skutterudite CoSb<sub>3</sub>의 열전특성
유신욱,박종범,조경원,장경욱,어순철,이정일,김일호,Yu S.W.,Park J.B.,Cho K.W.,Jang K.W.,Ur S.C.,Lee J.I.,Kim I.H. 한국재료학회 2005 한국재료학회지 Vol.15 No.2
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.
Effects of Bi on the Thermoelectric Properties of Mg2Si-Mg2Ge Solid Solutions
유신욱,Dong-Kil Shin,김일호 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.5
Mg2Si1−xGex:Bim (0.3 x 0.7, m = 0 or 0.02) solid solutions were synthesized by using asolid-state reaction (SSR) and were consolidated by hot pressing (HP). In the case of the undopedMg2Si1−xGex specimens, the electrical conduction changed from n-type to p-type at room temperaturefor x 0.7 due to the intrinsic properties of Mg2Ge. The electrical conductivity rapidlyincreased with increasing temperature, indicating a non-degenerate semiconducting behavior, anddecreased with increasing Ge content. However, all Bi-doped Mg2Si1−xGex solutions showed n-typeconduction. The carrier concentration was increased from 4.0 × 1017 to 1.9 × 1020 cm−3 by Bi doping,and the electrical conductivity was increased from 7.3 × 10 to 4.3 × 104 Sm−1. The absolutevalue of the Seebeck coefficient increased with increasing temperature, and the Seebeck coefficientranged from −91 to −224 μVK−1 for the Bi-doped specimens. Bi doping reduced the thermal conductivitiesof the Mg2Si1−xGex solid solutions at temperatures above 723 K. Mg2Si0.7Ge0.3:Bi0.02exhibited a maximum dimensionless figure-of-merit of 0.79 at 823 K.
Solid-state Synthesis and Thermoelectric Properties of Cr-doped MnSi1.73
신동길,유신욱,김일호 한국물리학회 2014 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.65 No.10
Cr-doped HMSs (higher manganese silicides), MnSi1.73 : Crx (x = 0, 0.005, 0.01, 0.02, 0.03), wereprepared by using a solid-state reaction and hot pressing. X-ray diffraction analysis and Rietveldrefinement confirmed the synthesis of MnSi1.73. The Cr atoms were confirmed to be soluble in theHMS structure because the lattice constant increased with increasing Cr content (x), and the solidsolubility limit of Cr was estimated as x = 0.01. All specimens showed p-type conduction andexhibited degenerate semiconductor characteristics at all temperatures examined (323 − 823 K). The Seebeck coefficient was decreased and the electrical conductivity was increased by Cr doping. The dimensionless thermoelectric figure of merit ZT was obtained as 0.36 at 823 K for MnSi1.73 :Cr0.005 and MnSi1.73 : Cr0.01 because the power factor was increased and the thermal conductivitywas decreased by Cr doping.