• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 추계학술발표대회 논문집
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• pp.183-188
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• 2002

Co-cured composite materials has its own characteristics, so its thermal expansion is different each other. The selection of tool material for co-cured composite part in high temperature more over $350^{circ}F$ and 50 Psi pressure have to consider part thermal expansion, size, shape, and economic aspect in production line. So it is important choose tooling material in manufacturing composite parts. We called the tool for airplane composite parts as BAJ (Bonding Assembly Jig). Composite parts are cured on the BAJ in autoclave. BAJ have to stable at high temperature over $350^{circ}F$ and 50 Psi pressure, Considering composite parts' dimensional tolerance compare to heat up in autoclave. This paper come from the results of the experiment at the composite parts production line and review other aircraft company's method for tooling This is for the engineer engaged in composite parts manufacturing.

• Journal of Mechanical Science and Technology
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• 제15권7호
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• pp.839-846
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• 2001

Some deep drawing characteristics at elevated temperatures were investigated for the SCPI steel sheets by using a Cr-coated die. For this investigation, six different temperatures between room temperature and 250$\^{C}$, and six different drawing ratios ranging from 2.4 to 2.9 were considered. As a result, the limiting drawing ratio, the maximum drawing force and the maximum drawing depth were found to be affected sensitively by temperature, and more stable through-thickness strain distribution was observed at elevated temperatures. Some experimental results compared favorably with theoretical results obtained by using the finite element method.

• 대한기계학회논문집
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• 제19권8호
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• pp.1989-1998
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• 1995

Characteristics of the flame propagation for normal and abnormal combustion in hydrogen premixture in a cylindrical constant-volume combustion chamber are studied numerically. A detailed hydrogen oxidation kinetic mechanism, mixture transport properties and a model describing spark ignition process are used. The calculated pressure-time history of the stable deflagration wave propagation agrees well with the experiment. The ignition of the premixture in the unburned gas, initiated by the hot spot, causes a transition from deflagration to detonation under some initial temperature and pressure. Under the initial conditions with high temperature and pressure, excessive ignition energy initiates a strong blast wave and a detonation wave that follows. The chemical reaction in the detonation wave is much more vigorous than that in the deflagration wave and the peak pressure in the detonation wave is much higher than the equilibrium value.

• Journal of the Optical Society of Korea
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• 제14권4호
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• pp.415-419
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• 2010

A phosphor-conversion white light source is demonstrated using an InGaN-based blue laser diode (LD) and a yellow-emitting phosphor excited by the blue LD. The photometric and colorimetric properties of this blue-LD-based white light source are characterized. When injection current of the LD is 100 mA, luminous flux and luminous efficiency of the white light are found to be over 5 lm and 10 lm/W, respectively. When injection current is >90 mA, luminance is estimated to be larger than 10 Mcd/$cm^2$. In addition, color characteristics of the white light such as chromaticity coordinates, a correlated color temperature, and a color rendering index are found to be quite stable as current and temperature of the LD varies. The demonstrated LD-based white light source is expected to be used in high-brightness illumination applications with good color stability.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1999년도 춘계학술대회논문집
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• pp.63-70
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• 1999

Some deep drawing characteristics to the elevated temperatures were investigated for the SCP1 steel sheets by using the Cr-coated die. For this investigations six steps of temperature ranges from room temperature to 25$0^{\circ}C$ and six kinds of drawing ratio from 2.4 to 2.9 were adopted. As a result the limiting drawing ration maximum drawing force and the maximum drawing depth were sensitively affected by the elevated temperatures and the more stable thickness strain distribution was observed to the elevated temperatures, Some experimental results were compared with analytical results using the DYNA-3D code.

• 한국식품영양학회지
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• 제5권2호
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• pp.144-149
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• 1992

Invertase was extracted from Korean ginseng(Panax ginseng C. A. Meyer) leaf with deionized water, and then prepared by ammonium sulfate(0.4~0.6 Sat.) fractionation, the enzymological properties of the invertase were investigated, and the results obtained were as follows. The optimum pH and temperature of the enzyme were pH 6.0 and 4$0^{\circ}C$ respectively. The enzyme was stable in the pH range of pH 6.0 to 8.0, and at the temperature below 4$0^{\circ}C$. The enzyme was inactivated completely by the treatment with some proteases(pepsin, trypsin, papain and ficin) and protein denaturants(8M urea and 6M guanidine-HCI), but not with glycosidases (a-amylase, $\beta$-amylase and glucoamylase). The enzyme catalyzed specifically the hydrolization of the $\beta$-fructofuranosides such as sucrose and inulin.

• 소성∙가공
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• 제8권3호
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• pp.221-221
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• 1999

Warm deep drawability in a square cup drawing was investigated using a newly developed high-strength steel sheet with retained austenite that was transformed into martensite during formation. For this investigation, six different temperatures between room temperature and 250℃, and five different drawing ratios ranging from 2.2 to 2.6 were considered. The results showed that the maximum drawing force and the drawing depth were affected by the change in temperature, and a more stable thickness strain distribution was observed at elevated temperatures. However, blue shortness occurred at over 200℃. FEM analysis using the LS-DYNA code was used to compare the experimental results with the numerical results for the thickness strain distribution.

• E2M - 전기 전자와 첨단 소재
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• 제10권8호
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• pp.756-762
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• 1997

In this paper the change of electrical properties of transformer oil due to electron beam irradiation is investigated. The specimens are produced with a some different dose of 0.5[Mrad], 1[Mrad] and 2[Mard] except for original specimen. The physical properties of each specimen is analyzed by using the FT-IR spectrum. So it is confirmed that carbonyl groups are increased according to the increase of electron beam dose and also that the nitric compounds are disappeared. The magnitude of dielectric dissipation factor appears maximum value by the contribution of dipoles and ions in the low temperature low voltage region and it is stable due to the saturation of carriers in the high temperature high voltage region in the electric conduction characteristics. Volume resistivity is also measured one of original specimen is larger than irradiated specimen.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 추계학술대회 논문집
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• pp.121-124
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• 1996

It is well known that the metallo- phthalocyanine (MPcs) are sensitive to toxic gaseous molecules such as NO$_2$and also chemically and thermally stable. Therefore, lots of MPcs have been studied for the potential chemical sensor for NO$_2$gas using quartz crystal microbalance(QCM) or electrical conductivity. In this study, thin films of octa(2-ethylhexyloxy) copper-phthalocyanine were prepared by Langmuir -Blodgett method and characterized by using UV-VIS spectroscopy and ellipsometry. Transfer condition, and characterization of LB films were investigated and preliminary results of current-voltage(I-V) characteristics of these films exposed to NO$_2$gas as a function of film thickness, temperature and temperature were discussed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 C
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• pp.491-493
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• 2000

The performance of insulate materials gets worse with stress time in power system and because this causes lowering of function and accidents in equipment, development and performance improvement of excellent insulate materials are needed to make stable system. In this paper, to study the influence of degradation in XLPE, inner semiconducting layer and outer semiconducting layer, we studied dielectric characteristics at temperature $25{\sim}100[^{\circ}C]$ and frequency $20{\sim}1[MHz]$ and volume resistivity at temperature $25{\sim}100^{\circ}C$, voltage.