• 한국세라믹학회지
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• 제30권10호
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• pp.791-796
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• 1993

The electro-magnetic properties of the Mn-Zn ferrite single crystal with small variation of Fe2O3 concentration at the high permeability composition, 53mol% Fe2O3-28.5mol% MnO-18.5mol% ZnO, have been studied for the VCR magnetic head application. With the increase of the Fe2O3 concentration, the Fe2+ concentration increased, the specific resistivity decreased, the secondary maximum permeability shifted to the lower temperature, and the initial permeability decreased. It was concluded that the small variation of $\pm$0.5mol% Fe2O3 concentration greatly affected the electro-magnetic properties of Mn-Zn ferrite single crystals. At the composition of 53mol% Fe2O3, the initial permeability was comparatively high (650 at 5MHz) and its temperature dependence was small.

• Bulletin of the Korean Chemical Society
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• 제11권1호
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• pp.11-15
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• 1990

The temperature dependence of electrical conductivities and thermoelectric power of $I_2$-doped poly(1,4-penylene vinylene-co-2,5-dimethoxy-1,4-phenylene vinylene)s [poly(PV-co-DMPV)] and poly(1,4-phenylene vinylene-co-2,5-thienylene vinylene)s [poly(PV-co-TV)] were studied. The former copolymers were also doped with $FeCl_3$. All the samples used were in thin film forms. The temperature dependence of electrical conductivity implies that the variable range hopping conduction mechanism applises to these systems. The activation energy for the electrical conduction in dimethoxy-phenylene vinylene (DMPV) copolymers ranged from about 7 to 30 meV depending on the polymer composition and the nature of the dopant. It was significantly higher for $I_2$-doped thienylene vinylene (TV) copolymers, namely 90-200 meV. The values of the room temperature thermoelectric power were $30-70{\mu}V/K$ for DMPV copolymer and $100-800{\mu}V/K$ for TV copolymers. Anisotropy in the electrical conductivities was also studied for oriented films obtained by uniaxial stretching of the precursor polymer films.

• Journal of Magnetics
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• 제13권1호
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• pp.11-18
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• 2008

This study examines a new macroscopic ferrimagnet, Co-TbN. This ferrimagnet, consisting of two metallic phases, Co and TbN, demonstrated the typical macroscopic ferrimagnet properties of a magnetic compensation point and a negative giant magnetoresistance (GMR). The Co-TbN system with 32% TbN composition showed 0.72% GMR in magnetic fields up to 8 kOe at room temperature and 9% GMR in 40 kOe at 250 K. In the Co-TbN system, GMR exhibited a different dependence on temperature from that of ordinary GMR materials whose negative magnetoresistance decreases with increasing temperature. In contrast to ordinary GMR materials whose negative magnetoresistance decreases with increasing temperature, the GMR effect in the Co-TbN system increased with increasing temperature, due to the increase of ferromagnetic alignment of the Co and TbN in the magnetic field caused by the decreased exchange coupling with increasing temperature.

• 한국마이크로전자및패키징학회:학술대회논문집
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• 한국마이크로전자및패키징학회 2002년도 추계기술심포지움논문집
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• pp.169-172
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• 2002

Silver pastes for inner conductor in the Low Temperature Co-fired Ceramics (LTCC) are composed of silver powder, binder, solvent and additives. The composition of the chemicals have influence on rheology, printability, shrinkage rate, etc. In this study, commercial Ag pastes and Ag pastes made in KETI were investigated to find the relationship between characteristics of Ag paste and solid contents. Ag pastes with 68~90 wt% Solid Contents were tested. Substrate/paste matching property and conductivity of the conductor lines showed large dependence on solid contents of Ag paste.

• 한국재료학회지
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• 제4권1호
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• pp.75-80
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• 1994

2-관능성 DGEBA-4-관능성 TGDDM 블렌드를 DDM으로 경화시킨 경호물의 굴곡 특성과 열 안정성을 혼합비에 대하여 조사하였다. 굴곡 탄성율과 유리 전이 온도는 TGDDM이 증가 될수록 증대되었고, 20-40 중량%의 TGDDM조성에서 불연속적으로 변화하는데, 이것은 이 저성 부근에서 ductile/brittle의 구조적 상변화가 일어나고 있기 때문인 것으로 추정된다. TGDDM성분이 증가될수록 최대 열분해 온도는 고온쪽으로 shift되는 경향을 보이지만, 분해에 대한 활성화 에너지는 오히려 감소했다.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2007년도 특별 심포지엄 논문집
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• pp.27-30
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• 2007

Martian meteorites are the only available Martian Materials on Earth. A suite of demagnetization experiments, temperature dependence of saturation magnetization, scanning electron microscopy, and electron microprobe analysis were carried out to characterize the remanent magnetization carriers of Martian meteorite SaU 008. A stable paleomagnetic record of SaU 008 originates from a newly found spinel ((Fe, Cr, Ti)-spinel) whose composition has never been documented (or identified as magnetic).

• Applied Science and Convergence Technology
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• 제24권3호
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• pp.47-52
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• 2015

The correlation between admittance and dielectric spectroscopy of dielectric relaxation in lead scandium noibate, have been investigated. Lead scandium niobate, with composition $PbSc_{0.5}Nb_{0.5}O_3$, was prepared by conventional solid state synthesis. Conductance Y'(G), susceptance Y"(B) and capacitance C of lead scandium niobate as a function of frequency and temperature were measured. From the temperature-dependence of RLC circuit, insight into physical significance of the dielectric properties of lead scandium niobate is obtained. The relative strong frequency dependent of dielectric properties in lead scandium niobate is observed, and the phase transition occurred at a broad temperature region. Also, the value of critical exponent ${\gamma}$=1.6 showed on heating process. The long relaxation times part enlarged diffuse by conductivity effects with increasing temperature, and the ordering between $Sc^{3+}$ and $Nb^{5+}$ in PSN influences complex admittance and dielectric properties. Confirmed the typical characteristic of lead-type relaxor in the Raman spectra of lead scandium niobate and major ranges are between 400 and $900cm^{-1}$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 디스플레이 광소자분야
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• pp.102-105
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• 2004

With varying rapid thermal annealing (RTA) temperature, luminescent properties of ZnMgS:Mn thin film sputter-deposited with one target were measured. Although all samples have the same composition, $Zn_{1-x}Mg_xS:Mn$ (x=0.25) can emit luminescence between 580 and 614 nm, which is controlled by only RTA temperature. It is understood that the energy band gap shift of ZnMgS:Mn thin film phosphor occurs with varying RTA temperature.

• 전자공학회논문지A
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• 제29A권11호
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• pp.84-90
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• 1992

The dependence of electrical characteristics of RuO$_2$-based thick film resistors on the RuO$_2$ contents, glass composition variation and the firing temperatures was measured. The sheet resistance of resistors decreased as the contents of RuO$_2$ increased and at firing temperatures higher than C, the sheet resistance increased as the firing temperature increased. In case of using lead borosilicate glass-containing $Bi_{2}O_{3}$, the sheet resistance decreased as the contents of $Bi_{2}O_{3}$ increased. TCR changes from negative to positive values as RuO$_2$ contents increased and from positive to negative values as the firing temperature increased. TCR increased to positive values as $Bi_{2}O_{3}$ increased in the glass.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1990년도 추계학술대회 논문집
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• pp.65-67
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• 1990

In this study, (0.80-x)Pb($Mg_{1/3}Nb_{2/3}$)$O_3$-$PbTiO_3$-Pb($Ni_\frac{1}{2}W_\frac{1}{2}$)$O_3$ 0.05$\leq$x$\leq$0.20) ceramics were fabricated by the mixed oxide method, the sintering temperature and time were 950∼1200[$^{\circ}C$], 2[hr], respectively. The dielectric and structural properties with composition and sintering temperature were investigated for the application as multilayer ceramic capacitors. Dielectric constant of 0.70PMN-0.2PT-0.10PNW composition with repeated calcination was increased rapidly. Increasing the Pb($Mg_{1/3}Nb_{2/3}$)$O_3$-$PbTiO_3$-Pb($Ni_\frac{1}{2}W_\frac{1}{2}$)$O_3$ contents from 0.05 to 0.20 [mol], phase transition temperature was shifted from 68 to 2[$^{\circ}C$] and dielectric constant was decreased while sintered density was increased. In the specimens containing 0.10, 0.15[mol] of PNW, dielectri constants at room temperature were exhibited the highest values 11199, 10114, respectively. Resistivity of specimens were $10^{10}$ ∼ $10^{12}$($\Omega$.m) and there was no dependence on sintering temperature and composition.