• Title/Summary/Keyword: mass property

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휴대용 멀티미디어 기기에서 메타데이터 활용을 강화한 파일 시스템 구조 (A File System Architecture for Enriched Metadata in Portable Multimedia Devices)

  • 윤현주
    • 대한임베디드공학회논문지
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    • 제2권1호
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    • pp.1-8
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    • 2007
  • In this paper, we developed a file system architecture for portable multimedia devices. To enhance user convenience, the information about the stored files should be easily retrieved and organized. We defined NMD (Networked MetaData), which can organize the files in networked fashion by attaching user-defined attributes and relation between files. The NMD is stored in flash memory to utilize its nonvolatile property and low-power consumption, while multimedia files are stored in hard disk, an inexpensive mass storage. The experimental implementation showed that this architecture was able to save about 10% power compared to the hard disk NMD-store.

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HWCVD를 이용하여 Microcrystalline film 성장시 Silane 농도에 따른 박막 성장 특성

  • 박승일;이정택;이정철;허윤성;김근주
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2010년도 하계학술대회 논문집
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    • pp.267-267
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    • 2010
  • The structural and electrical properties of microcrystalline silicon films were investigated by hot wire chemical vapor deposition(HWCVD) often called catalytic chemical vapor deposition(Cat-CVD). The Si microcrystalline phase is easily controlled by changing the rate of the silane concentration of $SiH_4$ to $H_2$ during deposition. The Structural property was observed by Raman and SEM. Photo-conductivity and dark conductivity, and photo-sensitivity were observed by Sunsimulator (AM 1.5 illumination). The film color was changed by the variation of silane concentration. HWCVD is useful for the formation of Si thin films for solar cell and needs further commercialized development for mass production.

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수화 온도 저감형 결합재를 이용한 매스콘크리트 현장적용에 관한 연구 - 실내시험 중심으로- (A Study on Field Application of the Mass Concrete using Hydration Temperature-Reducing Binder - Focused on the Laboratory Test -)

  • 이지환;이진우;박희곤;강창구;배연기;이재삼
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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    • pp.259-260
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    • 2010
  • 본 연구는 저발열 콘크리트의 적용성 검토를 위한 기초적 시험으로서, 각각의 배합조건 및 규격별 물리적 성질 및 수화열 저감특성을 알아보고자 하였다.

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A Theoretical Model of Critical Heat Flux in Flow Boiling at Low Qualities

  • Kim, Ho-Young;Kwon, Hyuk-Sung;Hwang, Dae-Hyun;Kim, Yongchan
    • Journal of Mechanical Science and Technology
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    • 제15권7호
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    • pp.921-930
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    • 2001
  • A new theoretical critical heat flux (CHF) model was developed for the forced convective flow boiling at high pressure, high mass velocity, and low quality. The present model for an intermittent vapor blanket was basically derived from the sublayer dryout theory without including any empirical constant. The vapor blanket velocity was estimated by an axial force balance, and the thickness of vapor blanket was determined by a radial force balance for the Marangoni force and lift force. Based on the comparison of the predicted CHF with the experimental data taken from previous studies, the present CHF model showed satisfactory results with reasonable accuracy.

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수소 확산화염의 구조에 미치는 Lewis 수의 영향 (Effects of Lewis number on hydrogen diffusion flame structure)

  • 김후중;김용모;안국영
    • 대한기계학회논문집B
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    • 제21권9호
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    • pp.1126-1138
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    • 1997
  • An axisymmetric laminar jet diffusion flame has been numerically modelled. The present study employs the refined physical submodels to account for the detailed chemical kinetics and the variable transport properties. It is found that preferential diffusion resulting from variable transport properties significantly influences the hydrogen diffusion flame structure in terms of the spatial distribution for temperature, species concentration, thermal and mass diffusivity, Lewis number, and NO concentration. The preferential diffusion effects on the diffusion flame in the high-pressure environment are also discussed in detail.

3단 회전식 건조성형장치 설계 프로그램 개발 (A Development of Design System Program for the 3-pass rotary dryer)

  • 김태식;최윤환;도덕희;이연원
    • 동력기계공학회지
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    • 제10권2호
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    • pp.36-40
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    • 2006
  • In order to prevent the environmental pollution, the dryers are commonly used to treat sludge that one of sewages is polluting the quality of water. Generally, the drying method is various as to the property of material and use. Rotary dryer is a good apparatus to treat them. It is the way that is to make substance transmission and heat using hot air between sludge particle and heated gas. In this paper, we developed a 3-pass rotary dryer for a design program for the 3-pass rotary dryer with various conditions. The working conditions of dryer are a raw sludge feed rate, input & output water content and operation time etc.

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광리소그래피에서 최적 모양의 패턴 구현을 위한 포토마스크 역설계 (Reverse design of photomask for optimum fiedelity in optical lithography)

  • 이재철;오명호;임성우
    • 전자공학회논문지D
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    • 제34D권12호
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    • pp.62-67
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    • 1997
  • The optical lithography wit an ArF excimer laser as a light source is expected to be used in the mass production of giga-bit DRAMs which require less than 0.2.mu.m minimum feature size. In this case, the distortion of a patterned image becomes very severe, since the lithography porcess is performed at the resolution limit. Traditionally, the photomask pattern was designed and revised with trial-and-error methods, such as repeated execution of process simulators or actual process experiments which require time and effort. Ths paper describes a program which automatically finds an optimal mask pattern. The program divides the mask plane into cells with same sizes, chooses a cell randomly, changes the transparent/opaque property of the cell, and eventually genrates a mask pattern which produces required image pattern. The program was applied to real DRAM cell patterns to produce mask patterns which genertes image patterns closer to object images than original mask patterns.

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Black Cr 태양 선택흡수막의 SIMS 연구 (SIMS Investigation of Black Cr Solar Selective Coatings)

  • 이길동
    • 한국태양에너지학회 논문집
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    • 제34권4호
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    • pp.39-44
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    • 2014
  • The elemental composition of electro-deposited black Cr solar selective coatings before and after heating in air by using secondary ion mass spectrometry (SIMS) was investigated for optical property analysis. In addition, black Cr selective coating exposed by solar radiation for 5 months was compared with heated sample. SIMS investigation shows that $OH^+$ bearing ions were related to a near surface region of CrOH and CrO compound. The optical degradation of this coating after heating at $500^{\circ}C$ reveals that diffusion of the Cu and Ni elements in substrate material, the chemical interactions adjacent to the interface, and the interface width broadening.

철도안전성능시험설비 구축 체계 개선에 관한 연구 (A Study on Improving the Constructing System of Railway Safety Test Facilities)

  • 김윤미;최경진;조연옥
    • 한국철도학회:학술대회논문집
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    • 한국철도학회 2010년도 춘계학술대회 논문집
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    • pp.2034-2039
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    • 2010
  • As a mass transportation system, a railway contains potential risks that may result in a high death rate and property losses. Accordingly, Railroad Safety Technology R&D Corps. is adopting the plan of the construction of Railway Safety Test Facilities as a part of the Railway Total Safety Project to enhance the railway safety, and carrying out researches on effective project management methods with Systems Engineering techniques. When a system or a service is realized, such as the Railway Total Safety Project, it needs to be verified by requirements and the process of verification is to check whether customers/stakeholders requirements have been properly transformed into a system or a service. Recently, building the standardized verification system up could be the solution to reduce possible system-failed risks. To support that, we propose the more effectual verification method of constructing the Railway Safety Test Facilities applying the systems engineering tool to the research.

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마이크로파 가열기법에 의한 저열 포틀랜드시멘트 콘크리트의 조기강도 추정에 관한 실험적 연구 (An Experimental Study on the Early Strength Estimation of Belite Cement Concrete by Microwave Method)

  • 이민경;황병준;전판근;박병근;김성식;정상진
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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    • pp.1041-1046
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    • 2003
  • The most recent building trend is going large, high rise, high strength as overlarge project is developing in domestic construction business. Belite cement has properties like low heat, excellent long term strength, and durability without admixture (fly ash, silica fume). So, Belite cement is suitable for mass structure which is needed high strength, high fluidity and low heat property. This study is to examine the possibility of site adoption microwave-use early strength estimation method. Based on the existed study related the portland cement, the interrelation between Belite cement and microwave-use early strength estimation method is required.

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