• Journal of the Korean Society for Heat Treatment
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• v.13 no.2
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• pp.108-114
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• 2000

The effects of heat treatments in Al-Si-Mg alloys on the microstructure and hardness have been investigated by the optical microscope, scanning electron microscope(SEM), and Rockwell hardness tester. The materials of various compositions are melted in a vacuum induction furnace under argon atmosphere. Five different Al alloys are prepared from commercial purity aluminium, magnesium and Al-25Si alloy. Two types of aging treatments are performed: i) Isothermal aging of the specimens at $150^{\circ}C$, $170^{\circ}C$ and $190^{\circ}C$. ii) Pre-aging of the specimens at $60^{\circ}C$, $80^{\circ}C$ and $100^{\circ}C$, and followed by final-aging at $170^{\circ}C$ and $190^{\circ}C$. After the heat treatments, Rockwell hardness are measured with all the specimens.

• 식품문화 한맛한얼
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• v.2 no.3
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• pp.114-118
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• 2009

막걸리는 탁주이지만, 탁주가 모두 막걸리인 것은 아니다. 우리는 막걸리와 탁주를 뒤섞어서 사용한다. 탁주는 그 색깔을 보아 회주(灰酒), 백주(白酒)라고도 했고, 그 형상을 보아 재주(滓酒)라고도 했다. 막걸리는 옛 문헌에서는 막걸리 요, 또는 탁료라는 표현을 많이 썼다. 한자로 막걸리(莫乞里) 또는 탁백이(濁白伊)라고 쓰기도 했는데, 이는 차음해서 표현한 것이다.

• Proceedings of the Korean Vacuum Society Conference
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• 2008.08a
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• pp.240-240
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• 2008

• Journal of the Korean Chemical Society
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• v.26 no.2
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• pp.114-115
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• 1982

• Applied Microscopy
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• v.39 no.2
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• pp.175-183
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• 2009

In this paper we present sub-50 pm resolution images of atom columns simulated with the negative of the second derivative of the exit-plane wave function (EPW). The EPW can be retrieved from a focal series reconstruction in the (high resolution) transmission electron microscopy (HRTEM). The simulated images are for Si and InAs in [114] and [116] orientations, which give about sub-50 pm separations of atom columns. The theoretical reason for the validity of this method is given from analysis based on the kinematical diffraction theory, and the limitation for applicability of this method also is discussed.

• Journal of Radiation Protection and Research
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• v.25 no.2
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• pp.109-114
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• 2000

The SI unit of specific absorption rate (SAR) in W/kg in the electromagnetic (EM) field as non-ionizing radiation is exactly same as the SI unit of absorbed dose rate in Gy/s in the ionizing radiation field. The SI unit of both physical quantities can be expressed in $[m^{\cdot}s^{-3}]$. Where, the unit of absorbed dose, Gy stands for Gray. In EM biological interactions, the SAR equations are derived and the characteristics of EM field energy absorption in terms of the SAR are discussed and described on the mathematical basis.

• Journal of the Korean institute of surface engineering
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• v.33 no.1
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• pp.10-16
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• 2000

Characteristics of cavitation erosion resistance of Fe-20Cr-1Si-1C-xMn(x=0, 5, 15) alloys were investigated by SEM and XRD analysis. The effects on strain-induced transformations were considerably reduced with increasing the amounts of Mn due to twining that occurred at 5, 15Mn alloys, activating cavitation erosion rates(mg/$\textrm{cm}^2$) which varied as 0.055, 0.114 and 0.160mg/$\textrm{cm}^2$ for 0, 5, 15Mn. From the results, it was found that the addition of Mn element in Fe-base alloy provides more cracking sites at twins rather than absorbing strain energies, so accelerates cavitation erosion rates.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.3
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• pp.114-119
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• 2007

Dielectric properties of quartz glass and $Si_3N_4$ are investigated using the waveguide method from room temperature to $800^{\circ}C$. For the case of dielectric constant, $Si_3N_4$ showed similar increase with quartz glass up to $300^{\circ}C$, but less increase from $300^{\circ}C$ to $800^{\circ}C$. For the case of loss tangent, those showed gradual increase with temperature except of some temperature points. The loss tangent of $Si_3N_4$ and quartz glass increased up to 18.2% and 12.5% respectively. Through these researches, high temperature dielectric properties of silicon nitride materials are characterized.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.237-240
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• 1991

In this paper, silicon oxynitride(SiON) films were chemically deposited by 193 nm Excimer laser irradiated parallel to the substrate. the laser pulse energy was 80 mJ, repetetion rate was 80 Hz and the laser average power was 6.4 watt, the gas ratio of $N_2O/NH_3$ was 0.75, the substrate temperature was $300^{\circ}C$, and the chamber pressure was 2 torr. And then, the interface state density($N_{ss}$) was characterized by DLTS(Deep Level Transient Spectroscopy). In addition, the capture cross section($\sigma$) and activation energy(${\Delta}E$) was also obtained. The resulting Nss values were $5.5{\times}10^{10}-3.2{\times}10^{11}(eV^{-1}cm^{-2})$, $\sigma$ was $6.64{\times}10^{-20}-2.114{\times}10^{-17}(cm^2)$, the ${\Delta}E$ of two peaks were $8.93{\times}10^{-2}$(eV), 0.375(eV).

• Journal of Korea Foundry Society
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• v.13 no.4
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• pp.342-349
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• 1993

The purpose of this study is to obtain basic information on the particle dispersion, the coefficient of thermal expansion and the thermal conductivity of compocasted Al-xSi-2Cu-1Mg/ySiC(x:6, 12, 18. $y:0{\sim}10wt.%$) composite. With increasing the content of SiC particles, the thermal expension coefficient and the thermal conductivity decrease. The coefficient of thermal expension between 20 and $300^{\circ}C$ is $21.3{\times}10^{-6}/^{\circ}C{\sim}18.0{\times}10^{-6}/^{\circ}C$ for the Al-Si alloys and $18.4{\times}10^{-6}/^{\circ}C{\sim}16.0{\times}10^{-6}/^{\circ}C$ for the composite with 10wt.% SiC. The thermal conductivity at $300^{\circ}C$ is $121{\sim}169W{\cdot}m^{-1}{\cdot}k^{-1}$ for the Al-Si alloys and $114{\sim}159W{\cdot}m^{-1}{\cdot}k^{-1}$ for the composite with 10wt.% SiC.