• Journal of the Korean Magnetics Society
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• v.5 no.3
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• pp.191-196
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• 1995

NiCuZn ferrites were prepared by a solid-state reaction and sintered at $900^{\circ}C$ for 5 hours. Its properties were investigated by controlling the ferrite composition and processing. NiCuZn ferrite with a composition of ${(Ni_{0.2}Cu_{0.2}Zn_{0.6}O)}_{1.02}{(Fe_{2}O_{3})}_{0.98}$ was found to have the maximum initial permeability as a result of the variation of Cu content and the (Ni+Cu)/Zn ratio. Curie temperature($T_{c}$) of NiCuZn ferrite was decreased with the larger Cu content and increased with the larger Ni content. NiCuZn ferrites of ${(Ni_{0.2}Cu_{0.2}Zn_{0.6}O)}_{1-w}{(Fe_{2}O_{3})}_{1+w}$ composition milled for 20~80 hours had the maximum initial permeability at w=-0.015 and Curie temperature ($T_{c}$) was decreased with the increasing of $Fe_{2}O_{3}$ deficiency(w).

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.95-98
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• 2007

In this paper, we make an analysis of electromagnetic wave absorption properties of $TiO_2$ in W-band. Therefore, we fabricated some samples in different composition ratio of $TiO_2$ and CPE. And the material properties of samples are calculated from S-parameter of samples using $\ell-2\ell$ method. We analyze absorption properties and complex relative permittivitis of samples. As a result, it has verified that absorption properties of sample containing $TiO_2:CPE=70:30wt.%$ have been excelled in W-band.

• Korean Journal of Materials Research
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• v.14 no.6
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• pp.394-398
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• 2004

A Ti47Al1.7W-3.7Zr alloy was oxidized between $900^{\circ}C$ and $1050^{\circ}C$, and the oxide scales formed were studied. The oxide scales consisted primarily of an outer$TiO_2$ layer, an intermediate $Al_2$$O_3$-rich layer, and an inner mixed ($TiO _2$ + $Al_2$$O_3$) layer. Besides $TiO_2$ and $Al_2$$O_3$, oxidation led to the formation of some $Ti_2$AlN and TiN. Both W and Zr were preferentially segregated below the intermediate $Al_2$$O_3$-rich layer. Tungsten in the oxide scale was present as $WO_3$ and ${Ti}_{x}$$W_{1-x}$, whereas zirconium as monoclic-$ZrO_2$ and tetragonal-$ZrO_2$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.370-370
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• 2010

The effects of adding higher-valence impurities on the bipolar resistive switching characteristics of Pt/$NiO_{1+x}$/TiN MIM stacks and physical properties were investigated. $NiO_{1+x}$ films with 14% W deposited at 20% oxygen partial pressure exhibited the bipolar resistance switching characteristics in Pt/$NiO_{1+x}$/TiN MIM stacks, while $NiO_{1+x}$ films with 8.2% W show unipolar resistance switching behavior. The relationship of W-doping and the crystallinity was studied by X-ray diffraction. The metallic Ni contents and $WO_x$ binding states with W amount was investigated by XPS. Our result showed that the metallic Ni, $WO_x$ binding states, and crystallinity in $NiO_{1+x}$ played an important role on the bipolar resistive switching.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05a
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• pp.106-111
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• 1996

600MWe급 상업용 가압경수로의 무붕산운전 가능성을 핵설계 측면에서 검토하였다. 기본 원자로 핵연료 형태는 AP600 기준으로 무붕산 노심이 가능하도록 핵연료 농축도, BP 재질/갯수/위치/농도, 제어봉의 재질/위치/갯수등의 설계 변수등을 변화시켰다. 핵연료 농축도는 1.95w/o, 2.9w/o, 3.5w/o를 사용하였으며, BP의 갯수는 8에서 24개까지 사용하였으며, 재질은 Gd$_2$O$_3$, 농도는 축방향 출력분포를 평탄화 시키기 위하여 10w/o-14w/o를 사용하였다. 제어봉 설계에서 재질은 경제적이며, 제어봉가가 큰 B$_4$C를 사용하였으며, 반응도 제어에는 weak 제어봉을 사용하여 출력분포에 대한 영향을 최소화 하도록 설계하였다. 또한 출력분포제어에는 독립적으로 작동되는 고반응도가의 제어봉을 설정하여 노심 상부에서 동작하게 함으로써 반응도에 미치는 영향이 적도록 설계하였다. 설계 결과 아직 안전성 확보 여부에 대한 연구가 수행되지 않은 상태이나 주기초에서 주기말까지 잉여반응도를 1% 미만으로 유지하고, 축방향 BP zoning이 이루어지면 현재의 상업용 원자로에도 무붕산 운전이 가능할 것으로 판단된다. 또한 주기초 A.O.가 -14%, 제어봉의 삽입과 인출에 따른 국부 첨두치가 2.16으로 나타나 안전성 확보에도 큰 어려움은 없을 것으로 생각된다.

• Journal of Electrochemical Science and Technology
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• v.14 no.4
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• pp.377-387
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• 2023

Ni-W/Al₂O₃ nano-composites were electrodeposited on mild steel substrate for mechanical and corrosion resistance applications. This study focused on the preparation of Ni-W/Al₂O₃ nano-composite coating with various quantity of Al₂O₃ incorporations. The addition of Al₂O₃ in the electrolytes were varied from 1-10 g/L in electrolytes and the Al₂O₃ incorporation in Ni-W/Al₂O₃ nano-composite coatings were obtained from 1.82 to 13.86 wt.%. The incorporation of Al₂O₃ in Ni-W alloy matrix influenced the grain size, surface morphology and structural properties were observed. The distributions of Al₂O₃ particle in alloy matrix were confirmed using electron microscopy (FESEM and TEM) and EDAX mapping analysis. The crystal structure informations were studied using X-ray diffraction method and it confirms that the deposits having cubic crystal structure. The better corrosion rate (0.87 mpy) and microhardness (965 HV) properties were obtained for the Ni-W/Al₂O₃ nano-composite coating with 13.86 wt.% of Al₂O₃ incorporations.

• Journal of Sensor Science and Technology
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• v.7 no.5
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• pp.364-371
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• 1998

A novel antifuse has been developed for field programmable gate arrays (FPGA's) as a voltage programmable link with Al/$BaTiO_3/SiO_2$/TiW-silicide. The proper program voltage can be obtained by adjusting the deposition thickness of $BaTiO_3$ film. When a negative voltage was applied at bottom TiW-silicide electrode of the antifuse, based on $BaTiO_3(120{\AA})$/$SiO_2(120{\AA})$, the program voltage was about l4.4V and on-resistances were ranged between 40 and $50{\Omega}$. The current-voltage characteristics of antifuses are consistent with a Frenkel-Poole conduction model. However, there are some deviations depending on bias polarity that are probably due to the difference in the interface properties between Al/$BaTiO_3$ and TiW-silicide/$SiO_2$.

• Journal of Pharmaceutical Investigation
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• v.32 no.4
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• pp.291-297
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• 2002

For preventing and curing the stretching mark, TECA Niosome/W/O system creams were formulated using Titrated Extract of Centella Asiatica (TECA) which is well known for its excellent wound healing effect. The lipid-water partition coefficients and the stabilities of TECA were evaluated and TECA Niosome/W/O system (TECA N/W/O) creams were prepared with different concentrations of cetyl alcohol and ceramide. TECA N/W/O cream was evaluated with respect to their rheological properties, permeation through excised skin of hairless mouse and in vitro and in vivo accumulation in the skin of hairless mouse. In addition, dermal thicknesses of hairless mouse skins were determined following the in vivo application of TECA N/W/O cream and control cream. TECA N/W/O creams showed pseudoplastic flow and hysteresis loop. The permeation of TECA from formulations through excised skin of hairless mouse did not observed. Amount of accumulated drug in the excised skin of hairless mouse was deσeased with an increase in the concentration of cetyl alcohol and showed no relationship with concentration of ceramide. Amount of accumulated drug in formulation A-3 was higher than in niosome suspension and other formulations. In in vivo experiment, amount of accumulated drug in formulation A-2 and A-3 was much higher than that of niosome suspension. Being treated with the N/W/O cream for 8 weeks, the dermal thickness of hairless mouse skin was increased 3.2 times than that of 16 weeks-control group.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.38 no.2
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• pp.119-131
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• 2012

The W/O emulsion is widely used for cosmetics because of its water-proofing benefit and long-lasting moisturizing effect. However, because of low stability of the W/O emulsion, it is very important to control the concentration of electrolyte and emulsifying agent, and ratio of water phase. Among these factors, we focused on the effects of different structures of emulsifying agents on the change of stability. Emulsifying agents were sorted into polyglyceryl ester, silicone and sugar series. We also examined the emulsifyingability of emulsifier by changing the ratio of normal and silicon oil in the oil phase. Through these experimental results, we figured out the property of w/o emulsion depending on the types of emulsifiers, and observed the stability of emulsion considering the change of particles and viscosity over time.

• Applied Chemistry for Engineering
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• v.26 no.6
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• pp.666-673
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• 2015

In this paper the selective reduction catalyst (SCR) for controlling the NOx at high temperature range was studied. XRD and FT-IR BET analysis was also performed to determine the structural properties and adsorption/desorption characteristics of the catalyst. In the case of anatase $TiO_2$ support, a negligible NOx conversion was observed, but the $W/TiO_2$ catalyst made using W as a active metal showed an excellent ability to remove NOx. In particular, the $W/TiO_2$ exhibited a rapid increase in the catalytic activity due to the presence of W for the NOx conversion compared to that of using the pure $TiO_2$ at a high temperature range over $400^{\circ}C$. In addition, the phenomenon of reduced reaction activity due to the heat shock for a long time was found to be suppressed.