• Journal of the Korean institute of surface engineering
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• v.45 no.6
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• pp.242-247
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• 2012

Yb-doped ITO (ITO:Yb) films were deposited on unheated non-alkali glass substrates by magnetron cosputtering using two cathodes (DC, RF) equipped with the ITO and $Yb_2O_3$ target, respectively. The composition of the ITO:Yb films was controlled by adjusting the RF powers from 0 W to 480 W in 120 W steps with the DC power fixed at 70 W. The ITO:Yb films had a higher crystallization temperature ($200^{\circ}C$) than that of the ITO films ($170^{\circ}C$), which was attributed to both larger ionic radius of $Yb^{3+}$ and higher bond enthalpy of $Yb_2O_3$, compared to ITO. This amorphous ITO:Yb film post-annealed at $170^{\circ}C$ showed a resistivity of $5.52{\times}10^{-4}{\Omega}cm$, indicating that a introduction of Yb increased resistivity of the ITO film. However, these amorphous ITO:Yb films showed a high etching rate, fine pattering property, and a very smooth surface morphology above the crystallization temperature of the amorphous ITO films (about $170^{\circ}C$). The transmittance of all films was >80% in the visible region.

• BMB Reports
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• v.37 no.6
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• pp.735-740
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• 2004

Hepatitis C virus (HCV) is a causal agent of the chronic liver infection. To understand HCV morphogenesis, we studied the assembly of HCV structural proteins in insect cells. We constructed recombinant baculovirus expression vectors consisting of either HCV core alone, core-E1, or core-E1-E2. These structural proteins were expressed in insect cells and were examined to assemble into particles. Neither core-E1 nor core-E1-E2 was capable of assembling into virus-like particles (VLPs). It was surprising that the core protein alone was assembled into core-like particles. These particles were released into the culture medium as early as 2 days after infection. In our system, HCV structural proteins including envelope proteins did not assemble into VLPs. Instead, the core protein itself has the intrinsic capacity to assemble into amorphous core-like particles. Furthermore, released core particles were associated with HCV RNA, indicating that core proteins were assembled into nucleocapsids. These results suggest that HCV may utilize a unique core release mechanism to evade the hosts defense mechanism, thus contributing to the persistence of HCV infection.

• Journal of Electrical Engineering and Technology
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• v.6 no.4
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• pp.527-534
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• 2011

In the present paper, the characteristics of Mega-Flux$^{(R)}$, JNEX-Core$^{(R)}$, amorphous and ferrite cores are compared to the inductor of buck-boost converters for Hybrid Electric Vehicles. Core losses are analyzed at the condition of 10 kHz sine wave excitations, and permeability fluctuations vs. temperature and magnetizing force will be analyzed and discussed. Under the specifications of the buck-boost converter for 20 kW THS-II, the power inductor will be designed with Mega-Flux$^{(R)}$ and JNEX-Core$^{(R)}$, and informative simulation results will be provided with respect to dc bias characteristics, core and copper losses.

• Journal of Powder Materials
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• v.13 no.4 s.57
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• pp.285-289
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• 2006

Co-Fe-Ni-B-Si-Cr based amorphous strips containing nitrogen were manufactured via melt spinning, and then devitrified by crystallization treatment at the various annealing temperatures of $300^{\circ}C{\sim}540^{\circ}C$ for up to 30 minutes in an inert gas $(N_2)$ atmosphere. The microstructures were examined by using XRD and TEM and the magnetic properties were measured by using VSM and B-H meter. Among the alloys, the amorphous ribbons of $Co_{72.6}Fe_{9.8}Ni_{5.5}B_{2.4}Si_{7.1}Cr_{2.6}$ containing 121 ppm of nitrogen showed relatively high saturation magnetization. The alloy ribbons crystallized at $540^{\circ}C$ showed that the grain size of $Co_{72.6}Fe_{9.8}Ni_{5.5}B_{2.4}Si_{7.1}Cr_{2.6}$ alloy containing 121 ppm of nitrogen was about f nm, which exhibited paramagnetic behavior. The formation of nano-grain structure was attributed to the finely dispersed Fe4N particles and the solid-solutionized nitrogen atoms in the matrix. Accordingly, it can be concluded that the nano-grain structure of 5nm in size could reduce the core loss within the normally applied magnetic field of 300A/m at 10kHz.

• Journal of the Korean Magnetics Society
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• v.17 no.3
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• pp.128-132
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• 2007

The thermal and magnetic properties of amorphous (FeCo)SiBNb ribbon alloys with high glass forming ability have been investigated. The glass forming ability was enhanced by Co substitution in amorphous ($Fe_{1-X}Co_X)_{72}Si_4B_{20}Nb_4$ alloys with the thickness of about $40{\mu}m$. With the increase in Co content, the temperature range of supercooled liquid phase increased indicating the high glass forming ability of the Co-added alloys. Further the ac permeability increased, and the core loss decreased considerably by Co substitution, while small change in $B_8$ (magnetic flux density at 800 A/m) was observed. The frequency characteristics of permeability deteriorated as compared to conventional amorphous ribbon alloys with the thickness of about $20\;{\mu}m$ due to the increased skin effect.

• Design & Manufacturing
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• v.13 no.2
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• pp.17-21
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• 2019

In this study, selective laser sintered 3D printing mold core and metal core were used to investigate the difference of the thickness shrinkage from the gate of the injection molded part at a constant interval. SLS 3D printing mold core was made of nylon-based PA2200 powder and the metal core was manufactured by conventional machining method. As the PA2200 powder material has low strength, thermal conductivity and high specific heat characteristics compared with metal, molding conditions were set with the consideration of molten temperature and injection pressure. Crystalline resin(PP) and amorphous resin(PS) with low melting temperature and viscosity were selected for the injection molding experiment. Cooling time for processing condition was selected by checking the temperature change of the cores with a cavity temperature sensor. The cooling time of the 3D printing core was required a longer time than that of the metal core. The thickness shrinkage of the molded part compared to the core depth was measured from the gate by a constant interval. It was shown that the thickness shrinkage of the 3D printing core was 2.02 ~ 4.34% larger than that of metal core. In additions, in the case of metal core, thickness shrinkage was increased with distance from the gate, on the contrary, in the case of polymer core showed reversed aspect.

• Journal of the Korean Magnetics Society
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• v.5 no.1
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• pp.8-14
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• 1995

The magnetic properties of an $Fe_{87}Zr_{7}B_{5}Ag_{1}$(at.%) amorphous alloy have been investigated as a function of annealing temperatures to clarify its application potential as a core material for high-frequency use by adding a small amount of insoluble element of Ag. A new excellent soft magnetic material was developed. The amorphous alloy produced by relatively low temperature annealing at $T_{a}=400^{\circ}C$ exhibited very high initial permeability$(\mu_{i})$ of 288,000 at 1kHz and 2mOe, very low coercivity$(H_{c})$ of 15mOe and low core loss$(W_{c})$ of 50W/kg at 100kHz and 1,000G which is comparable with Co-based amorphous alloys, respectively. It is notable that the values obtained in the present study are the best magnetic properties among various kinds of Fe-based soft amorphous materials reported up to date. The reasons for the achievement of good soft magnetic properties are presumably due to the homogeneous formation of very fine $\alpha$-Fe clusters with the size of 2~3nm in an amorphous matrix, which can be deduced from the increase of resistivity and the TEM observation. The very fine $\alpha$-Fe clusters embedded in an amorphous matrix had a great influence on reduction of magnetostriction and refinement of magnetic domain.

• Electrical & Electronic Materials
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• v.10 no.8
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• pp.813-818
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• 1997

In this study the thin film air core and magnetic core inductors consisting of planar coil and/or CoNbZr amorphous magnetic layers on a Si substrate were fabricated as spiral type by using rf magnetron sputtering and wet etching methods. The etchant solution was achieved by iron chloride solution(17.5 mol%) mixed with HF (20 mol%) during 150 sec which etched Cu films and CoNbZr/Cu/CoNbZr multi-layer films. They were about 10${\mu}{\textrm}{m}$ of thickness and 10$\times$10 mm$^2$of size. The properties of thin film magnetic core inductor were 400 nH of Q value at 10 MHz and the resonance frequency was about 300 MHz.

• Proceedings of the KIEE Conference
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• 1993.11a
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• pp.79-81
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• 1993

In this paper, the iron loss of a amorphous transformer is calculated by the specific iron loss curve, after calculating flux densities in core using magnetic equivalent circuit method and FEM. In iron loss analysis using FEM, lamination model of amorphous transformer is transformed into anisotropy model, and it is known that the result is almost equal compared with the result of analysis using magnetic equivalent circuit method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1994.05a
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• pp.120-122
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• 1994

We examined the magnetic properties as a function of annealing temperature of the as-quenched $Fe_{87}Zr_{7}B_{5}Ag_{1}$ amorphous alloy. The values of $H_{c}$=30m0e, $B_{a}$=0.44T and ${\mu}$i=146000 at $300^{\circ}C$ annealing treatment are obtained. The excel lent soft magnetic properties seem to result from the annihilation of quenching-Induced internal stress by the heat treatment and the change of microstructure due to the different relaxation behavior owing to adding insoluble element such as Ag. Therefore, the $Fe_{87}Zr_{7}B_{5}Ag_{1}$ amorphous alloy is quite promising for practical use as a core material in various transformers of high transformers of high frequency.