• 제목/요약/키워드: Trapping

검색결과 928건 처리시간 0.029초

Avalnche주입에 따른 dry oxide와 wet oxide의 캐리어 트랩핑에 관한 연구 (A study on the carrier trapping characteristics of the dry and wet oxide films under the avalanche injection)

  • 정경호;정양희;박영걸
    • E2M - 전기 전자와 첨단 소재
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    • 제6권2호
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    • pp.115-120
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    • 1993
  • 본 연구에서는 dry oxide와 wet oxide로 MOS capacitor를 제작하여 avalanche 전자주입 실험으로 산화막의 캐리어 트랩핑특성을 조사하였다. dry oxide에서는 avalanche 전자주입 시 전자 trapping이 주도적으로 일어났다. wet oxide에서는 주입 초기에 전자 trapping이 주도적이다가 hole trapping이 주도적으로 바뀌게 되는 turn-around 현상이 일어났다. 주입시간이 길어지면 다시 전자 trapping이 주도적으로 되는 또 한번의 turn-around 현상이 일어났다. 산화막의 트랩 parameter를 결정하기 위해 실험결과를 기초로 하여 종류가 다른 여러 트랩을 가지는 계에 대한 캐리어 트랩핑 이론식을 세워서 실험결과와 curve-fitting한 결과 실험치와 잘 일치하는 곡선을 얻었다.

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유압 피스톤 펌프의 폐입 구간에서의 압력 변동 특성 (Pressure Variation Characteristics at Trapping Region in Oil Hydraulic Piston Pumps)

  • 곽재련;오석형;정재연
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 2003년도 학술대회지
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    • pp.329-334
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    • 2003
  • Design of pre-compression region(trapping region) of the valve plate is an important element to minimize the pressure fluctuation in a cylinder and in discharge process, and pump noise. In this study, we tried to prove what the characteristics of the oil hydraulic pump would be according to the angle of the trapping region. Three kinds of asymmetrical valve plates were used. As a result, we found that by designing the trapping region, the slope of the pressure rise in the cylinder port from low-pressure suction region to high-pressure discharge region is relaxed and the pressure fluctuation width and the discharge pressure pulsation are reduced. Therefore, because the pump gets smooth pressure fluctuation and low fluid Impact, the pump noise is reduce.

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Ideal Internal Carotid Artery Trapping Technique without Bypass in a Patient with Insufficient Collateral Flow

  • Chung, Joon-Ho;Shin, Yong-Sam;Lim, Yong-Cheol;Park, Min-Jung
    • Journal of Korean Neurosurgical Society
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    • 제45권4호
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    • pp.260-263
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    • 2009
  • Internal carotid artery (ICA) trapping can be used for treating intracranial giant aneurysm, blood blister-like aneurysms and ICA rupture during the surgery. We present a novel ICA trapping technique which can be used with insufficient collaterals flow via anterior communicating artery (AcoA) and posterior communicating artery (PcoA). A patient was admitted with severe headache and the cerebral angiography demonstrated a typical blood blister-like aneurysm at the contralateral side of PcoA. For trapping the aneurysm, the first clip was placed at the ICA just proximal to the aneurysm whereas the distal clip was placed obliquely proximal to the origin of the PcoA to preserve blood flow from the PcoA to the distal ICA. The patient was completely recovered with good collaterals filling to the right ICA territories via AcoA and PcoA. This technique may be an effective treatment option for trapping the aneurysm, especially when the PcoA preservation is mandatory.

Light trapping 개선을 통한 n-i-p 플렉서블 미세결정질 실리콘 박막 태양전지의 효율 향상 (Enhancement of n-i-p flexible microcrystalline silicon thin film solar cell efficiency through improved light trapping)

  • 장은석;백상훈;이정철;박상현;송진수;이영우;조준식
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2010년도 추계학술대회 초록집
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    • pp.58.1-58.1
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    • 2010
  • Stainless Steel의 유연한 기판을 사용하여 ZnO:Al/Ag의 후면전극에서 Ag 증착 실험조건 변화를 통해서 light trapping을 개선한 n-i-p 구조의 플렉서블 미세결정질 실리콘 박막 태양전지를 제작하였다. 실험 방법으로 마그네트론 스퍼터를 사용하여 Stainless Steel 기판 위에 ZnO:Al/Ag를 증착하여 후면전극으로 사용되는 back reflector를 제작하였으며 그 위에 미세결정질 실리콘 박막을 증착하였다. Back reflector에서 Ag 박막의 증착 온도가 증가할수록 표면결정 성장으로 roughness가 증가하여 반사도를 증가하였다. 또한, Ag 박막 증착 두께와 압력 변화에 따른 광학적 특성변화를 Atomic Force Microscope(AFM), Scanning Electron Microscopy(SEM),UV-visible-nIR spectrometry로 조사하여 최적의 조건을 찾았으며 개선된 back reflector의 특성이 n-i-p 구조의 플렉서블 미세결정질 실리콘 박막 태양전지에 적용하여 light trapping의 증가가 태양전지에서 광학적인 특성 변화 및 효율 향상에 영향을 주는지 Photo IV와 EQE(External Quantum Efficiency)를 통하여 조사하였다.

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Hydrogen Diffusion in APX X65 Grade Linepipe Steels

  • Park, Gyu Tae;Koh, Seong Ung;Kim, Kyoo Young;Jung, Hwan Gyo
    • Corrosion Science and Technology
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    • 제5권4호
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    • pp.117-122
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    • 2006
  • Hydrogen permeation measurements have been carried out on API X65 grade linepipe steel. In order to study the effect of steel microstructure on hydrogen diffusion behavior in linepipe steel, the accelerated cooling condition was applied and then three different kinds of microstructures were obtained. Hydrogen permeation measurement has been performed in reference to modified ISO17081 (2004) and ZIS Z3113 method. Hydrogen trapping parameters in these steels were evaluated in terms of the effective diffusivity ($D_{eff}$), permeability ($J_{ss}L$) and the amount of diffusible hydrogen. In this study, microstructures which affect both hydrogen trapping and diffusion were degenerated pearlite (DP), acicular ferrite (AF), bainite and martensite/austenite constituents (MA). The low $D_{eff}$ and $J_{ss}L$ mean that more hydrogen can be trapped reversibly or irreversibly and the corresponding steel microstructure is dominant hydrogen trapping site. The large amount of diffusible hydrogen means that corresponding steel microstructure is predominantly reversible. The results of this study suggest that the hydrogen trapping efficiency increases in the order of DP, bainite and AF, while AF is the most efficient reversible trap.

엔지니어드 터널베리어 메모리 적용을 위한 $HfO_2$ 층의 전하 트랩핑 특성 (Charge trapping characteristics of high-k $HfO_2$ layer for tunnel barrier engineered nonvolatile memory application)

  • 유희욱;김민수;박군호;오세만;정종완;이영희;정홍배;조원주
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2009년도 하계학술대회 논문집
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    • pp.133-133
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    • 2009
  • It is desirable to choose a high-k material having a large band offset with the tunneling oxide and a deep trapping level for use as the charge trapping layer to achieve high PIE (Programming/erasing) speeds and good reliability, respectively. In this paper, charge trapping and tunneling characteristics of high-k hafnium oxide ($HfO_2$) layer with various thicknesses were investigated for applications of tunnel barrier engineered nonvolatile memory. A critical thickness of $HfO_2$ layer for suppressing the charge trapping and enhancing the tunneling sensitivity of tunnel barrier were developed. Also, the charge trap centroid and charge trap density were extracted by constant current stress (CCS) method. As a result, the optimization of $HfO_2$ thickness considerably improved the performances of non-volatile memory(NVM).

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Present Status of Thin Film Solar Cells Using Textured Surfaces: A Brief Review

  • Park, Hyeongsik;Iftiquar, S.M.;Le, Anh Huy Tuan;Ahn, Shihyun;Kang, Junyoung;Kim, Yongjun;Yi, Junsin;Kim, Sunbo;Shin, Myunghun
    • Transactions on Electrical and Electronic Materials
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    • 제17권5호
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    • pp.275-279
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    • 2016
  • This is a brief review on light trapping in Si based thin film solar cells with textured surfaces and transparent conducting oxide front electrodes. The light trapping scheme appears to be essential in improving device efficiency over 10%. As light absorption in a thin film solar cells is not sufficient, light trapping becomes necessary to be effectively implemented with a textured surface. Surface texturing helps in the light trapping, and thereby raises short circuit current density and its efficiency. Such a scheme can be adapted to single junction as well as tandem solar cell, amorphous or micro-crystalline devices. A tandem cell is expected to have superior performance in comparison to a single junction cell and random surface textures appears to be preferable to a periodic structures.

Rapid Identification of Methylglyoxal Trapping Constituents from Onion Peels by Pre-column Incubation Method

  • Kim, Ji Hoon;Kim, Myeong Il;Syed, Ahmed Shah;Jung, Kiwon;Kim, Chul Young
    • Natural Product Sciences
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    • 제23권4호
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    • pp.247-252
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    • 2017
  • The methylglyoxal (MGO) trapping constituents from onion (Allium cepa L.) peels were investigated using pre-column incubation of MGO and crude extract followed by HPLC analysis. The peak areas of MGO trapping compounds decreased, and their chemical structures were identified by HPLC-ESI/MS. Among major constituents in outer scale of onion, 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone (2) was more effective MGO scavenger than quercetin (6) and its 4'-glucoside, spiraeoside (3). After 1 h incubation, compound 2 trapped over 90% MGO at a concentration of 0.5 mM under physiological conditions, but compounds 3 and 6 scavenged 45%, 16% MGO, respectively. HPLC-ESI/MS showed that compound 2 trapped two molecules of MGO to form a di-MGO adduct and compounds 3 and 6 captured one molecule of MGO to form mono-MGO adducts, and the positions 6 and 8 of the A ring of flavonoids were major active sites for trapping MGO.

식생여과대 유사 저감 효율 산정을 위한 정규화 방안 (A Study on Regularization Methods to Evaluate the Sediment Trapping Efficiency of Vegetative Filter Strips)

  • 배주현;한정호;양재의;김종건;임경재;장원석
    • 한국농공학회논문집
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    • 제61권6호
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    • pp.9-19
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    • 2019
  • Vegetative Filter Strip (VFS) is the best management practice which has been widely used to mitigate water pollutants from agricultural fields by alleviating runoff and sediment. This study was conducted to improve an equation for estimating sediment trapping efficiency of VFS using several different regularization methods (i.e., ordinary least squares analysis, LASSO, ridge regression analysis and elastic net). The four different regularization methods were employed to develop the sediment trapping efficiency equation of VFS. Each regularization method indicated high accuracy in estimating the sediment trapping efficiency of VFS. Among the four regularization methods, the ridge method showed the most accurate results according to $R^2$, RMSE and MAPE which were 0.94, 7.31% and 14.63%, respectively. The equation developed in this study can be applied in watershed-scale hydrological models in order to estimate the sediment trapping efficiency of VFS in agricultural fields for an effective watershed management in Korea.