• 제목/요약/키워드: chemical states

검색결과 851건 처리시간 0.024초

방사광의 원리와 지구환경과학에의 응용 (Earth and Environmental Sciences with Synchrotron Radiation)

  • 김영호
    • 암석학회지
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    • 제10권3호
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    • pp.212-221
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    • 2001
  • 방사광의 특성과 방사광의 발생원리에 대한 소개를 하였다. 매우 높은 스펙트럼 휘도와 매우 넓은 영역의 스펙트럼 범위, X-선 파장 조절 가능성과 고도의 지향성 및 집속성, 그리고 시간에 따른 순간파동 구조를 갖는 방사광을 이용하여 지질학 및 지구환경과학에 적용할 수 있는 실험기법을 기술하였다. 이에는 X선 토모그라피, XRF, XANES, EXAFS, 다이아몬드 앤빌 기기 및 라지 발륨 프레스를 이용한 고온-고압 연구와 에너지문제와 관련하여 원자력발전과 핵폐기물처리에 대한 것이 포함되어 있다. 이러한 실험기법은 광물 및 암석에 대한 화학성분, 결정구조 및 결합상태 분석이 가능하며, 광상학과 고생물학 및 환경학 분야에 적용할 수 있다. 또한 이 연구방법을 이용하면 지구내부물질의 거동에 관한 정보를 얻을 수 있다.

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Hydrogen Behaviors with different introduction methods in SiC-C Films

  • Huang, N.K.;Zou, P.;Liu, J.R.;Zhang, L.
    • 한국진공학회지
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    • 제12권S1호
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    • pp.1-6
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    • 2003
  • SiC-C films were deposited with r. f. magnetron sputtering on substrates followed by argon ion bombardment. These films were then permeated by hydrogen gas under the pressure of $3.23\times10^{7}$ Pa for 3 hours at temperature of 500K or bombarded with hydrogen ion beam at 5 keV and a dose of $1\times10^{18}$ ions/$\textrm{cm}^2$. SIMS, AES and XPS were used to analyze hydrogen related species, chemical bonding states of C, Si as well as contamination oxygen due to hydrogen participation in the SiC-C films in order to study the different behaviors of hydrogen in carbon-carbide films due to different hydrogen introduction. Related mechanism about the effects of hydrogen on the element of the SiC-C films was discussed in this paper.

$CHF_3$/$C_2$$F_6$ 반응성이온 건식식각에 의한 실리콘 표면의 오염 및 제거에 관한 연구 (A Study on the Silicon surface and near-surface contamination by $CHF_3$/$C_2$$F_6$ RIE and its removal with thermal treatment and $O_2$ plasma exposure)

  • 권광호;박형호;이수민;곽병화;김보우;권오준;성영권
    • 전자공학회논문지A
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    • 제30A권1호
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    • pp.31-43
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    • 1993
  • Thermal behavior and $O_{2}$ plasma effects on residue and penetrated impurities formed by reactive ion etching (RIE) in CHF$_{3}$/C$_{2}$F$_{6}$ have been investigated using X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) techniques. Decomposition of polymer residue film begins between 200-300.deg. C, and above 400.deg. C carbon compound as graphite mainly forms by in-situ resistive heating. It reveals that thermal decomposition of residue can be completed by rapid thermal anneal above 800.deg. C under nitrogen atmosphere and out-diffusion of penetrated impurities is observed. The residue layer has been removed with $O_{2}$ plasma exposure of etched silicon and its chemical bonding states have been changed into F-O, C-O etc.. And $O_{2}$ plasma exposure results in the decrease of penetrated impurities.

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BCl$_3$/SF6 gas chemistries에 의한 TiW막의 식각특성 연구 (A Study on the Etching Characateristics of TiW Films using BCl$_3$/SF6/ gas chemistries)

  • 권광호;김창일;윤선진;김상기;백규하;남기수
    • 전자공학회논문지D
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    • 제34D권3호
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    • pp.1-8
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    • 1997
  • The surface properties after plasma etching of TiW alloy using the chemistries of BCl$_{3}$ and SF$_{6}$ gases with varying mixing ratio have been investigated using XPS(X-ray photoelectron spectrocopy). The elements existed on the etched sampled have been extracted with BCL$_{3}$/SF$_{6}$ ratio and their chemical binding states have also been analysed. It was confirmed that the thickness of native oxide formed on the TiW films is thinner than 10nm by using Ar sputtering. At the same time, the roughness of etched surface has been esamnied using AFM (atomic force microscopy). on the basis of the basis of this results, the relations between the caanges of oxygen contents detected by XPS and the rouhness of etched surface have been discussed. And the etch rate and etched profile of Tiw films have been examined and the changes of the etch rate and etched prfile have been discussed with XPS results. From XPS results, the role of passivation layer consisted of Ti-S compound with XPS results. From XPS results, the role of passivation layer consisted of Ti-S compound has been proposed. Ti-S compound seems to make a role of passivation layer that surpresses Ti-O formation.ion.

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4비트 SONOS 전하트랩 플래시메모리를 구현하기 위한 기판 바이어스를 이용한 2단계 펄스 프로그래밍에 관한 연구 (A Study on a Substrate-bias Assisted 2-step Pulse Programming for Realizing 4-bit SONOS Charge Trapping Flash Memory)

  • 김병철;강창수;이현용;김주연
    • 한국전기전자재료학회논문지
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    • 제25권6호
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    • pp.409-413
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    • 2012
  • In this study, a substrate-bias assisted 2-step pulse programming method is proposed for realizing 4-bit/1-cell operation of the SONOS memory. The programming voltage and time are considerably reduced by this programming method than a gate-bias assisted 2-step pulse programming method and CHEI method. It is confirmed that the difference of 4-states in the threshold voltage is maintained to more than 0.5 V at least for 10-year for the multi-level characteristics.

Dry Etching Properties of HfAlO3 Thin Film with Addition O2 gas Using a High Density Plasma

  • Woo, Jong-Chang;Lee, Yong-Bong;Kim, Jeong-Ho
    • Transactions on Electrical and Electronic Materials
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    • 제15권3호
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    • pp.164-169
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    • 2014
  • We investigated the etching characteristics of $HfAlO_3$ thin films in $O_2/Cl_2/Ar$ and $O_2/BCl_3/Ar$ gas, using a high-density plasma (HDP) system. The etch rates of the $HfAlO_3$ thin film obtained were 30.1 nm/min and 36 nm/min in the $O_2/Cl_2/Ar$ (3:4:16 sccm) and $O_2/BCl_3/Ar$ (3:4:16 sccm) gas mixtures, respectively. At the same time, the etch rate was measured as a function of the etching parameter, namely as the process pressure. The chemical states on the surface of the etched $HfAlO_3$ thin films were investigated by X-ray photoelectron spectroscopy. Auger electron spectroscopy was used for elemental analysis on the surface of the etched $HfAlO_3$ thin films. These surface analyses confirm that the surface of the etched $HfAlO_3$ thin film is formed with nonvolatile by-product. Also, Cl-O can protect the sidewall due to additional $O_2$.

원자력발전소의 정량적인 안전 해석을 위한 사건수목 기법의 응용 (Application of Event Tree Technique for Quantification of Nuclear Power Plant Safety)

  • 김시달;진영호;김동하;박수용;박종화
    • 한국안전학회지
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    • 제15권2호
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    • pp.126-135
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    • 2000
  • Probabilistic Safety Assessment (PSA) is an engineering analysis method to identify possible contributors to the risk from a nuclear power plant and now it has become a standard tool in safety evaluation of nuclear power plants. PSA consists of three phases named as Level 1, 2 and 3. Level 2 PSA, mainly focused in this paper, uses a step-wise approach. At first, plant damage states (PDSs) are defined from the Level 1 PSA results and they are quantified. Containment event tree (CET) is then constructed considering the physico-chemical phenomena in the containment. The quantification of CET can be assisted by a decomposition event tree (DET). Finally, source terms are quantitatively characterized by the containment failure mode. As the main benefit of PSA is to provide insights into plant design, performance and environmental impacts, including the identification of the dominant risk contributors and the comparison of options for reducing risk, this technique is expected to be applied to the industrial safety area.

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난반사 표면의 3D 스캐닝을 위한 정전분말코팅 연구 (A Study on Electrostatic Powder Coating for 3D Scanning of Diffused Surfaces)

  • 맹희영;이명상
    • 한국생산제조학회지
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    • 제24권1호
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    • pp.56-62
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    • 2015
  • Using an optical 3D scanning device to collect data from a diffused reflection surface is very difficult. To solve this problem, there are many applications including a spray-type developer and silicon molds. However, using a developer can cause chemical reactions between objects and particles of the developer and uneven surfaces on the object. To overcome these problems, we suggest an electrostatic powder coating method for even coating of particles onto surfaces for collecting 3D shape data. We have developed an automatic, electrostatic powder-coating machine and performed three different experiments to compare this system with a laser interferometer and a T-scan 3D scanner. As a result, we could ascertain the various characteristics of this new method, including good sensitivity for the various surface states of the bare surface, developer, and electrostatic powder coating. Finally, we verified the outstanding scanning performance and were able to demonstrate that this method achieves quality than traditional methods.

나노유체의 열전도도 향상에 관한 새로운 메커니즘 (A New Mechanism for Enhanced Beat Transport of Nanofluid)

  • 이동근;김재원
    • 대한기계학회논문집B
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    • 제30권6호
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    • pp.560-567
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    • 2006
  • Although various conjectures have been proposed to explain abnormal increase in thermal conductivity of nanofluids, the detailed mechanism could not be understood and explained yet. The main reason is primarily due to the lack of knowledge on the most fundamental factor governing the mechanisms such as Brownian motion, liquid layering, phonon transport, surface chemical effects and agglomeration. By applying surface complexation model for the measurement data of hydrodynamic size, zeta potential, and thermal conductivity, we have shown that sulfate charge state is mainly responsible for the increase in the present condition and may be the factor incorporating all the mechanisms as well. Moreover, we propose a new model including concepts of fractal and interfacial layer. The properties such as thickness and thermal conductivity of the layer are estimated from the surface charge states and the concept of electrical double layer. With this, we could demonstrate the pH dependences of the layer properties and eventually of the effective thermal conductivity of the nanofluid.

화염가수분해 증착 공정에서 기판온도의 변화에 따른 다성분 입자의 부착 및 소결특성에 관한 연구 (Effect of Substrate Temperature on Multi-component Particle Deposition and Consolidation in Flame Hydrolysis Deposition)

  • 신형수;백종갑;최만수
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 춘계학술대회논문집B
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    • pp.428-433
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    • 2000
  • The consolidation behavior of multicomponent particles prepared by the flame hydrolysis deposition process is examined to identify the effects of Si substrate temperature. To fabricate multi-component particles, a vapor-phase ternary mixture of $SiCl_4(100 cc/min),\;BCl_3(30cc/min)\;and\;POCl_3,(5cc/min)$ was fed into a coflow diffusion oxy-hydrogen flame burner. The doped silica soot bodies were deposited on silicon substrates under various deposition conditions. The surface temperature of the substrate was measured by an infrared thermometer. Changes in the chemical states of the doped silica soot bodies were examined by FT-IR(Fourier-transformed infrared spectroscopy). The deposited particles on the substrate were heated at $1300^{\circ}C$ for 3h in a furnace at a heating rate of 10K/min. Si-O-B bending peak has been found when surface temperature exceeds $720^{\circ}C$. Correspondingly, the case with substrate temperatures above loot produced good consolidation result.

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