• Journal of Sensor Science and Technology
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• v.25 no.6
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• pp.440-446
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• 2016

This study introduces the characteristics of current-voltage (I-V) and impedance variance for $ZnO-Zn_2BiVO_6-Co_3O_4$ (ZZCo), which is sintered at $900^{\circ}C$, according to temperature changes. ZZCo varistor demonstrates dramatic improvement of non-linear coefficient, ${\alpha}=66$, with lower leakage current and higher insulating resistivity than those of ZZ ($ZnO-Zn_2BiVO_6$) from the aspect of I-V curves. While both systems are thermally stable up to $125^{\circ}C$, ZZCo represents a higher grain boundary activation energy with 1.05 eV and 0.94 eV of J-E-T and from IS & MS, respectively, than that of ZZ with 0.73 eV and 0.82 eV of J-E-T and from IS & MS, respectively, in the region above $180^{\circ}C$. It could be attributed to the formation of $V^*_o$(0.41~0.47 eV) as dominant defect in two systems, as well as the defect-induced capacitance increase from 781 pF to 1 nF in accordance with increasing temperature. On the other hand, both the grain boundary capacitances of ZZ and ZZCo are shown to decrease to 357 pF and 349 pF, respectively, while the resistances systems decreased exponentially, in accordance with increasing temperature. So, this paper suggests that the application of newly formed liquid phases as sintering additives in both $Zn_2BiVO_6$ and the ZZCo-based varistors would be helpful in developing commercialized devices such as chips, disk-type ZnO varistors in the future.

• Bulletin of the Korean Chemical Society
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• v.32 no.10
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• pp.3738-3742
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• 2011

Bismuth tribromide ($BiBr_3$) catalyzed Mannich-type reactions of N-acyliminium ions which generated in situ from N-benzyloxycarbonylamino p-tolylsulfones have been developed. In the presence of catalytic amount of $BiBr_3$, N-benzyloxycarbonylamino p-tolylsulfones prepared from aromatic and aliphatic aldehydes reacted with silyl enol ether and silyl enol ester under mild reaction conditions to afford N-Cbz-protected ${\beta}$-amino ketones and N-Cbz-protected ${\beta}$-amino esters in moderate to good yield, respectively.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.201-203
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• 1991

T. Kanal et al, were studied the superconducting properties in Bi system by mechanical grinding, in which the authors found that the samples ground degraded from the superconducting phases to nonsuperconducting phases. To obtain more information of the practical application in Bi system with high-Tc phase in this paper, these samples mechanically ground and the high-Tc phase properties of grinding powder samples were investigated.

• YAKHAK HOEJI
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• v.22 no.1
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• pp.22-26
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• 1978

The purposes of this investigation were to study the characteristic properties of bismuthoxynitrate formed by hydrolysis of bismuthnitrate according to various reaction conditions and to propose the property difference between synthesized pearl pigment and bismuthsubnitrate as pharmaceuticals by means of X-ray diffraction, IR, DTA and TGA. The pearl pigment could be obtained by reaction of bismuth nitrate-diluted nitric acid solution with cold water (5.deg.) agitation at lower pH. The pearl pigment was BiO. NO$_{3}$. 2H$_{2}$O. in composition and crystalline form was thin plate of monoclinic system and its combination with water was assumed to be hydrated hydrous form between Bi-H$_{2}$O bond. On the other hand, bismuthsubnitrate was 5BiO.4NO$_{3}$.6H$_{2}$O in composition and crystalline form was pillar of rhombic system and the bond between Bi and H$_{2}$O molecules was assumed to be hydrous form. The different properties between two compounds in structure are presumed to be caused by the hydrolysing conditions of bismuthnitrate respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.252-255
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• 1996

Superconducting current lead is one of the promising applications of the oxide high-Tc superconductors, because they have the advantage of decreasing heat conduction to low temperature region, comparing with a conventional cooper alloy lead. High critical current density is a key factor for the applications such as current lead. (Bi,Pb)$_2$Sr$_2$Ca$_2$Cu$_3$O$\_$x/ high Tc superconductor haute been investigated in terms of critical current density. Bi-2223 superconducting current lead made by CIP and solid state sintering process. Bi-2223 current lead that heat treated at 836$^{\circ}C$ for 240 h in 1/13 P$\_$O$_2$/ had over 150 A/$\textrm{cm}^2$ of critical current density at 77K. We knew that the superconducting properties of tube type current leads were better than rods type of them. And we investigated the relation of Bi-2223 formation and heat treatment condition by XRD and SEM analysis.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.39-40
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• 2005

Ferroelectric Eu-substituted $Bi_4Ti_3O_{12}$ (BET) thin films with a thickness of 200 nm were deposited on Pt(111)/Ti/SiO$_2$/Si(100) substrate by means of the liquid delivery MOCVD system and annealed at several temperatures in an oxygen atmosphere. At annealing temperature above $600^{\circ}C$, the microstructure of layered perovskite phase was observed. The remanent polarization of these films increased with increase in annealing temperature. The remanent polarization values ($2P_r$) of the BET thin films annealed at $720^{\circ}C$ were $37.71{\mu}C/cm^2$ at an applied voltage of 5 V.

• Journal of the East Asian Society of Dietary Life
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• v.12 no.3
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• pp.218-224
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• 2002

This study was undertaken to analyze chemical composition, macro- and micro-mineral contents of ostrich bone with flesh meat (BF), ostrich bone with flesh meat with herb medicine (BFll) and ostrich bone with internal organs (BI). Crude fat of the BFH was lower, but crude protein and crude ash of the BFH were significantly higher than those of the BF and the BI. Among the minerals, Ca, p, Mg, Fe, Cu, Zn content of the BFH were significantly higher than the content in the BF and the BI. The minerals, Pb, Cd and As were not detected in ostrich and herb medicine extracts. From the sensory test of ostrich and herb medicine, the preferences were in the fellowing order; ostrich bone with flesh meat with herb medicine (BFH), ostrich bone with flesh meat (BF), and ostrich bone with internal organs (BI) in extracts.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.05a
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• pp.73-76
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• 1999

We have fabricated and tested a Bi-based high temperature superconducting current lead system. Ag sheathed Bi-2223 mono-filament tapes of $I_c=8.4$ A at 77 K under self-field condition were fabricated using powder-in-tube(P1T) method. Multi-layer current leads can be made by stacking of Ag sheathed Bi-2223 mono-filament wires. The critical current of this 10-layer current lead is about 68 A. The contact resistance across the copper-current lead interface has been studied using current-voltage characteristics. At temperature below critical temperature the resistive contribution of the interface to the total contact resistance dominates. We have measured AC transport losses in a current lead at 77 K, 60 Hz by a transport method.

• Journal of Magnetics
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• v.10 no.4
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• pp.149-151
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• 2005

The electric properties of a single crystal bismuth telluride doped with a small concentration of Erbium, $Bi_{z-x}Er_xTe_3$ with x = 0.002, are investigated as a function of temperature. The resistivity was obtained by using the van der Pauw method. The measured electrical resistivity is 78 ${\mu}{\Omega}cm$ at 4.2 K. The charge density of $Bi_{z-x}Er_xTe_3$ is found to be $2{\times}10^{19}/cm^3$ at 4.2 K. It turns out that $Bi_{z-x}Er_xTe_3$ is a p-type semiconductor. It is discussed that the high mobility and less density support that $Bi_{z-x}Er_xTe_3$ is a potential sensor with high energy resolution. Comparison with an established material (i.e. Au:Er alloy) is also discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.198-203
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• 2000

This paper investigated the effects of doping elements on the Bi-Sr-Ca-Cu-O ceramics. The doping elements can be classified into four groups depending on their superconducting characteristics in the Bi-Sr-Ca-Cu-O structure. The first group of doping elements(Co, Fe, Ni and Zn) substitute into the copper site and can reduce the critical temperatures of the 2223 and 2212 phases. The second group of doping elements(Y and La) substitute into the Ca site and cause the disappearance of the 2223 phase and increase the critical temperatures in the 2212 phase. The third group of doping elements(P and K) have a tendency to decompose the superconducting phase and reduce the optimal sintering temperature. The fourth group of doping elements(B, Si, Sn and Ba) almost unaffected the superconductivity of the 2223 and 2212 phase.