• 제목/요약/키워드: Si(114)

검색결과 180건 처리시간 0.027초

Al-Si-Mg계 합금의 열처리에 의한 미세조직과 경도 변화 (A Study on the Microstructure and Hardness of Al-Si-Mg Alloys upon Heat Treatments)

  • 이세종;이성관;백남익
    • 열처리공학회지
    • /
    • 제13권2호
    • /
    • pp.108-114
    • /
    • 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.

  • PDF

우리 전통 술의 순례 - 탁주 또는 막걸리 이야기

  • 허시명
    • 식품문화 한맛한얼
    • /
    • 제2권3호
    • /
    • pp.114-118
    • /
    • 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.

  • PDF

HRTEM에서 50 pm 이하 분해를 주는 결정 밑 표면 파동함수의 2차 도함수의 시뮬레이션 영상들 (Simulated Images of the Second Derivative of the Exit-plane Wavefunction Giving Sub-50 pm Resolutions in HRTEM)

  • 김황수
    • Applied Microscopy
    • /
    • 제39권2호
    • /
    • pp.175-183
    • /
    • 2009
  • 이 논문에서 50 pm 이하의 원자열 분해상을 효과적으로 보여 주는 결정 밑 표면 파동함수(EPW)의 음(-)의 2차 도함수의 시뮬레이션 영상들이 나타나 있다. 그리고 해당 EPW는 HRTEM에서 일련의 비 초점 단계의 관찰 영상으로부터 얻을 수 있다. 이 논문에 나타난 시뮬레이션한 영상들은 대체로 50 pm 이하의 원자열 간격을 주는 Si과 InAs의 [114] 및 [116] 방위 축에 대한 것이다. 이 방법의 정당성에 대한 이론적 이유가 운동학적 회절이론을 기초로 한 분석에서 주어졌다. 그리고 그 응용성의 한계도 논의되었다.

Characteristics of Specific Absorption Rate (SAR) in Electromagnetic (EM) Dosimetry

  • Hwang, Sun-Tae;Choi, Kil-Oung
    • Journal of Radiation Protection and Research
    • /
    • 제25권2호
    • /
    • pp.109-114
    • /
    • 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.

  • PDF

Fe-20Cr-1Si-1C계 경면처리 합금의 cavitation erosion 저항성에 미치는 Mn 첨가의 영향 (Effect of Mn-Addition on the Cavitation Erosion Resistance of Surface-hardened Fe-20Cr-1Si-1C Aolly)

  • 김수철;박인호;장세기;김선진;강성군
    • 한국표면공학회지
    • /
    • 제33권1호
    • /
    • pp.10-16
    • /
    • 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.

  • PDF

질화규소 재료의 고온 유전물성 평가 (High Temperature Dielectric Properties of Silicon Nitride Materials)

  • 최두현
    • 한국군사과학기술학회지
    • /
    • 제10권3호
    • /
    • pp.114-119
    • /
    • 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.

DLTS 법(法)에 의한 Laser CVD SiON 막(膜)-Si 계(系)의 계면(界面) 특성(特性) (Laser CVD SiON-Si interface investigation by DLTS)

  • 천영일;김상욱;이승환;박지순;박근영;성영권
    • 대한전기학회:학술대회논문집
    • /
    • 대한전기학회 1991년도 추계학술대회 논문집 학회본부
    • /
    • pp.237-240
    • /
    • 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).

  • PDF

Al-xSi-2Cu-1Mg/ySiC(x:6, 12, 18. $y:0{\sim}10wt.%$)계 복합재료의 열적성질에 관한 연구 (A Study on the Thermal Properties of Al-xSi-2Cu-1Mg/ySiC(x:6, 12, 18. $y:0{\sim}10wt.%$) Composite Materials)

  • 박상준;조원용;강세선;임윤수;권혁무;윤의박
    • 한국주조공학회지
    • /
    • 제13권4호
    • /
    • pp.342-349
    • /
    • 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.

  • PDF