• Electrical & Electronic Materials
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• v.27 no.9
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• pp.12-16
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• 2014

• Resources Recycling
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• v.12 no.6
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• pp.19-25
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• 2003

This experiment was carried out to examine the effect of iron oxide roasting for Sr-ferrite magnet. Chloride content was decreased with raising the 2 nd roasting temperature of iron oxide for ruthner process iron oxide. The optimization temperature for roasting of ruthner process iron oxide was around $800^{\circ}C$ as average particle size 1.5∼1.9 $\mu\textrm{m}$, apparent bulk density 1.4 g/$m\ell$ and chloride content 0.05%. The relation between Br and HcJ by sintering temperature for Sr-ferrite magnet was found to be Br≒-0.258HcJ＋494. In case of having a vibrating disk mill for the ruthner process iron oxide, the magnetic properties were Br 421 mT and HcJ 251 kA/m.

• Journal of the Korean Ceramic Society
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• v.33 no.5
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• pp.572-582
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• 1996

The porous silicon was prepared in the condition of 70mA/cm2 and 5.10 sec and then oxidized at 800~110$0^{\circ}C$ MOS(Metal Oxide Semiconductor) structure was prepared by Al electrode deposition and analyzed by C-V (Capacitance-Voltage) characteristics. Dielectric constant of oxidized porous silicon was large in the case of low temperature (800, 90$0^{\circ}C$) and short time(20-30min) oxidation and was nearly the same as thermal SiO2 3.9 in the case of high temperature (110$0^{\circ}C$) and long time (above 60 min) It is though to be caused byunoxidized silicon in oxidized porous silicon film and capacitance increase due to surface area increment effect.

• Journal of Sensor Science and Technology
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• v.8 no.2
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• pp.202-209
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• 1999

Microstrip line was fabricated on the oxidized porous silicon layer which has nearly electrically and chemically identical properties with thermally oxidized silicon layer. Thick oxidized porous silicon layer of few tenth of micrometers was prepared by thermal oxidation of porous silicon layer on silicon substrate. Multi-step thermal oxidation process was used to obtain high Quality and thick oxidized silicon layer and to release thermal stress. Microstrip line was fabricated on the oxidized porous silicon layer. Its microwave characteristics were measured and the availability for MMIC substrate was investigated.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.182.1-182.1
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• 2013

Silver (Ag)는 높은 반사율을 가지고 있어 Top-Emission Organic Light Emitting Diode (T-OLED)의 반사전극으로 사용하기 적합하지만 일함수가 낮은 단점 (4.3 eV)을 가지고 있다. 이런 낮은 일함수를 증가시키기 위하여 Ag 박막 표면을 산화시켜 일함수를 증가시키기 위한 연구가 진행중에 있으며, 이 연구에서는 UV로 $O_3$을 발생시켜 Ag 박막 표면을 산화시키기 위한 연구를 진행하였다. 특히, Ag 박막 표면의 일함수 변화를 측정하기 위하여 SPM (Scanning Probe Microscopy)의 KPFM (Kelvin Probe Force Microscopy) mode를 적용하여 nano 영역에서의 일함수 변화를 surface potential로 측정하여 UV 표면 산화에 의한 표면 일함수 형상을 확인하였다. Ag 박막은 rf magnetron sputter를 사용하여, Si 기판위에 300nm 두께로 증착시켰다. 이후 $O_3$ 발생되는 UV 램프로 Ag 박막 표면 30초 간격으로 최대 5분간 산화시켰으며, 이후 KPFM mode를 사용하여 산화 시간에 따른 Ag 박막 표면의 potential 변화를 측정하였다. 0~3분간 산화된 Ag 박막 표면의 potential은 약 6 mV로 일정하였으나 3분 이후 최대 110 mV까지 급격하게 변화하는 것을 확인할 수 있었다. Ag 박막 표면의 RMS roughness는 UV 산화처리 전0.7 nm였으나, potential이 급격하게 증가하는 시점인 3분 이후 2.83 nm로 약 400% 이상 증가하였다. 이를 통해 $O_3$ 발생 UV 램프로 산화된 Ag 박막의 표면 물성은 처리 시간에 따라 급격히 변하는 것을 확인하였다.

• Journal of the Korean Society of Propulsion Engineers
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• v.23 no.2
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• pp.118-125
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• 2019

Metals exposed to high temperature/high pressure/oxidant excess environment of an oxygen excess pre-combustor may undergo rapid oxidation. In this study, the test facility to simulate the high temperature/high pressure/oxidant excess environment was constructed and the oxidation resistance evaluation was carried out for various metal materials. As a result, the discoloration of the metallic materials, the change in the surface roughness and the peeling of the metal surface were observed, and the weight change was also observed. The resulst showed that oxidation-resistant coating of a metal material of the combustor is indispensably required, and the use of XM-19, which has the highest content of Cr and Ni, is expected to provide more structural stability.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.30 no.6
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• pp.220-225
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• 2020

Gallium oxide nano-powder, the key starting material for IGZO target, is fabricated by gas phase synthesis using a new apparatus consist of reaction, transportation, and collection parts. As a result of gallium metal evaporation above 1150℃, Ga2O3 nano-powders, are successfully synthesized. The SEM images of the synthesized powders displace the spherical shaped powders without severe agglomeration. X-ray diffraction and PSA analysis show that the higher temperature at the reaction part results in the better crystallinity and larger powder size of the synthesized Ga2O3. To see the applicability to IGZO target, Ga2O3 nano-powders synthesized at 1250℃ are mixed with indium oxide and zinc oxide (In2O3 : Ga2O3 : ZnO = 1 : 1 : 1), and then sintered at 1400~1500℃. The highest sintered density of 5.83 g/㎤ (= 91 % of relative density) is achieved when sintered at 1450℃, showing better sinterability compared to the commercially available Ga2O3 powder, which has 5.61 g/㎤ of sintered density at the same condition.

• Resources Recycling
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• v.21 no.1
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• pp.30-40
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• 2012

Electric arc furnace slag is made in ironworks during steel refining, it is been increasing chemical and physical resistibility using ageing method of unstable state of melting steel slag for using concrete's fine aggregates. Which is been changing stable molecular structure of aggregates, it restrains moving of ion and molecule. In Korea, KS F 4571 has been prepared for using the electric arc furnace oxidizing slag to concrete aggregates(EFS). In this study, Electric arc furnace oxidizing slag is used in the PRCC(Polymer Rapid setting Cement Concrete) which is applied a bridge pavement of rehabilitation, largely. The results showed that the increment of compressive strength development by 10- 20%. The flexural strength of EFS-Con increased greatly as the electric arc furnace oxidizing slag changed. The compressive strength and flexural strength developed enough for opening the overlayed EFS-Con to the traffic after 4 hours of EFS-Con placement. The permeability of EFS-Con was evaluated as negligible due to its very low charge passed. Thus, EFS-Con could be used at repairing or overlaying the concrete at fast-track job sites.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.4 no.2
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• pp.3-11
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• 1998

Coating was carried out on liner components of B flute, single-wall corrugated board(SK180/S120/K200) to examine the effect of liner component coatings by oxidized starch on the properties of corrugated board. Both bursting strength and edgewise compression strength(ECS) of corrugated board were improved by coating of its liner components with oxidized starch. Bursting strength of corrugated board rapidly increased with an initial increase of coating weight, but as the coating weight further increased, there was no increase in bursting strength. The results showed 30.3% improvement for $2.32g/m^2$ coating on outside liner component, 36.8% improvement for $4.84g/m^2$ coating on inside liner component and 39.9% improvement for $7.16g/m^2$ coating on both liner components in bursting strength of corrugated board. Regardless of treated liner components, ECS of corrugated board was improved by coating of oxidized starch, and especially greater improvement was accomplished when corrugated board was coated on inside liner component or both liner components at low level of coating weight - 11.3% improvement for $1.58g/m^2$ coating on Inside liner component and 11.9% improvement for $2.99g/m^2$ coating on both liner components.

• Journal of the Korean Applied Science and Technology
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• v.32 no.4
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• pp.639-648
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• 2015

Some materials of fatty acids in the biodiesel affect the physical/chemical properties like density, kinematic viscosity, total acid number and oxidation stability by forming an organic fatty acid in combination with oxygen in the air. To solve the problem of the oxidative stability of biodiesel, various kinds of antioxidant has added and analyze the characteristics of the physical/chemical property changes by the addition of antioxidant. Oxidation stability increased by the increase of additives content. The TBHQ among the seven kinds of the additives showed the best performance. Also, 4 kinds of additives like propyl gallate, butyl-amine and pyrogallo has showed above 10 hr of oxidation stability at the addition of 500 ppm. In case of pyrogallo, this is not appropriate as an additive to suitable quality standards of total acid number. TBHA, DTBHQ of hydroquinone was satisfied with the quality standard of oxidation stability but the target of this research(above 10 hr) did not satisfied with oxidation stability. Propyl gallate is also a suitable at the quality standards of total acid number but it was shown not to be an appropriate to the additives due to increasing the total acid number by increasing of the content of additives at the addition of 500 ppm.