• 제목/요약/키워드: REF

검색결과 243건 처리시간 0.027초

철근콘크리트 구조물의 열화 진단시스템 개발 - 열화요인 진단을 중심으로 - (Development of Deterioration Diagnosis System for the R/C Structures - Mainly on Cause of Deterioration -)

  • 이장화;박홍석;유영찬;김도겸;송영철
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 1994년도 봄 학술발표회 논문집
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    • pp.243-248
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    • 1994
  • The purpose of this study is to develop Deterioration Diagnosis System for the Reinforced Concrete Structure which can be used preliminary in determining the factors causing deterioration by simple inspection and mapping of the indicators of deterioration. Total 29 items compromising material, structural and constructional factors causing deterioration were considered in this system. Also the indicators of deterioration were subdivided into 54 items such as concrete crack pattern and steel corrosion etc. Each indicator of deterioration was quantatified by allocating and giving grade to each item which has extra weight according to its conscquence. Satisfactory results were obtatined by applying this Diagnosis system to the indicators of deterioration in ref. [3]. Further research was required on the indicators of deterioration in construction site to enhance the field applicability of this system.

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Brevibacterium sp. CH1의 분리 및 특성 (Isolation ref Brevibacterium sp. CH1 and Properties of Its Enzyme)

  • 장호남;이처영;황준식
    • 한국미생물·생명공학회지
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    • 제17권5호
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    • pp.429-435
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    • 1989
  • A bacterial strain of Brevibaterium sp. CH1 was isolated and used to produce an enzyme (nitrile hydratase) necessary for earring out the bioconversion of acrylonitrile to acrylamide. The culture and reaction conditions, and medium optimization were studied for the strain. The conversion yield was nearly 100% with a trace amount of acrylic acid produced. The strain showed strong activity of nitrile hydratase toward acrylonitrile and extremely low activity of the amidase toward acrylamide. We sought optimum culture conditions for the formation of nitrile hydratase by Brevibacterium sp. CH1. The effects of temperature and pH on the activity of free and immobilized tells were investigated. The nitrite hydratase of Brevibacterium sp. CH1 acted not only on various aliphatic nitrites such as acrylonitrile, propionitrile and acetonitrile, but also on aromatic nitrile as nicotinonitrile.

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동해연안의 주택경관 유형별 인지 평가에 관한 연구 (A Study on evaluation of recognition with type of Housing landscape in Donghae Seaside)

  • 조원석;김흥기;김용기;신정섭
    • 한국농촌건축학회논문집
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    • 제8권1호
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    • pp.80-89
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    • 2006
  • This study is derived from relation between the natural landscape and architectural landscape. The type of landscape in Donghae seaside consist of three; Road, Mountain, Seaside. And we selected three landscapes about individual housing; Western, Traditional, Modern. This paper is analyzed 18-simulation scenes, which evaluated with semantic differential method in using 12-bipolar adjectives. The results of this study are as follows(ref: table 6). 1)The housing of western style do not correspond with landscape of Road, but landscape of mountain and seaside were suitable to the western style. 2)Mountain in Donghae seaside harmonizes with housing of traditional style. 3)Even though the housing of modern style were marked low assessment in three landscape, we found out relation, modern housing was well-matched with load landscape.

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국내 철근콘크리트 학교건물의 지진피해율 분포에 관한 연구 (Earthquake Damage Assessment of Reinforced Concrete School Buildings in Korea)

  • 전경주;위정두;이강석;황기태;윤석훈
    • 한국콘크리트학회:학술대회논문집
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    • 한국콘크리트학회 2010년도 춘계 학술대회 제22권1호
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    • pp.117-118
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    • 2010
  • 본 연구에서는 기존에 제안된 저층 철근콘크리트 건물의 간이 내진성능 평가법1)을 토대로 국내 S, G 및 J지역에 현존하는 철근콘크리트 학교건물을 대상으로 내진성능을 평가하여 결과를 검토함과 동시에 지진피해율 정도를 추정하여 입력지진동 크기(0.1g~0.25g)에 따른 지진피해율 분포를 상정하였다.

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시간 영역에서 아날로그 DLL의 Bandwidth 와 Locking Speed 관계의 수식적 분석 (Numerical Analysis of the Relation of the Bandwidth and Locking Speed of the Analog DLL in Time Domain)

  • 류경호;정성욱
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2008년도 하계종합학술대회
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    • pp.607-608
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    • 2008
  • Locking time of the DLL is the important design issue in case of clock gating for low power system. For precise analysis of the locking speed of the DLL, this paper analyzes the locking process of the DLL in time domain. Analysis result shows that the value of the DLL bandwidth over reference frequency should be limited to below 1 ($i.e.w_n/F_{REF}<1$) for the stable operation and relation between bandwidth and lock time is expressed by log function.

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가변 중력장하의 밀폐 용기 내 자연 대류 (Natural Convection in an Enclosure under Time Dependent Gravity)

  • 김기현;현재민;곽호상
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 추계학술대회논문집B
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    • pp.556-561
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    • 2000
  • Comprehensive numerical computations are made of side-heated squire cavity which is exposed to time dependent external mechanical forcing. Numerical solutions are acquires to the governing two-dimensional Navier-Stokes equations for a Boussinesq fluid. Time dependent heat transfer characteristics of interior fluid are analyzed to illustrate resonance phenomenon. When system is exposed to pure sinusoidal mechanical forcing, the numerical results disclose that the basic mechanism of resonance of mechanical forcing is same as that of thermal forcing of Ref. [3, 9]. In comparatively small amplitude of mechanical forcing, thermal characteristics of the system are similar to basic system(${\varepsilon}=0$).

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풍동을 이용한 밸브제트에서 난류제트 유동고찰 (Investigation on the tunulent flow of the valve jet experimented using a wind tunnel)

  • 노병준
    • 대한기계학회논문집
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    • 제5권4호
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    • pp.257-265
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    • 1981
  • A modified subsonic wind tunnel was employed to investigate the turbulent flow of a valve jet. To effectuate this experimental study, an actual valve and valve seat of a diesel engine were equipped at its outlet (ref. Fig. 3) Theoretically, using the equation of motion of Navier-Stokes in the chlindrical coordinates, the turbulent equation of motion for the incompressible fluid was derived with three assumptions; steady flow (.delta./.delta.t=0), axisymmetry and revolutionary homogeneity(.delta./.delta..phi.=0), no ensemble revolution (V.iden.0). Experimentally, mean and fluctuation velocities have been measured in the redial direction. With a assumption of a non-dimensional velocity distribution equation, a sami-emperical similarity profile equation of the jet flow have been derived, whose empirical constants were deterimed graphically with the data obtained.

스프링 연결 병렬형 탄성 역진자의 비선형 $H_2/H_\infty/LTR$ 제어 (Nonlinear $H_2/H_\infty/LTR$ Control of the Parallel Flexible Inverted Pendulum Connected by a Spring)

  • 한성익
    • 제어로봇시스템학회논문지
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    • 제6권5호
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    • pp.356-366
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    • 2000
  • In this paper, a nonlinear $H_2/H_\infty/LTR$ control for the flexible inverted pendulum of a parallel type with Coulomb friction is presented. The dynamic equation for this system is derived by the Hamilton's principle and assumed-mode method. This hard nonlinear system can be modeled by a the quasi-linear state space model using the REF method. It is shown that the $H_2/H_\infty$ control can be applied to the nonlinear controller design of the system having Coulomb frictions if the proper LTR conditions are satisfied. In order to present the usefulness of the suggested control method, the nonlinear $H_2/H_\infty/LTR$ controller is designed to control the Position of the end point of the flexible inverted pendulum that has Coulomb frictions present in actuator parts. The results are given via computer simulations.

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자동차 기관용 전자제어 연료분사 및 점화시기 제어기 개발 (Development of Electronic Control Fuel Injection and Spark Timing Controller for Automobile Engine)

  • 김태훈;민규식;양성환;장형성
    • 한국안전학회지
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    • 제10권4호
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    • pp.22-35
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    • 1995
  • In this paper, an electronic control unit is developed using 16bit microcomputer for automobile engine. This system incorporate AFS(Air Flow Sensor) of Hot Wire type, DIS(Direct Ignition System), ISC(Idle Speed Control) system, CAS(Cranke Angle Sensor) and other peripheral device. This system includes hardware and software to facilitate precision control of both fuel injection and ignition timing. Especially, this controller consists of position signal(180 teeth) and 4 REF signals. Present system has maximum $720^{\circ}CA$ delay. But this system has maximum $180^{\circ}CA$. Thus, this system is able to precision control both fuel injection and ignition timing.

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Compiling Multicopy Single-Stranded DNA Sequences from Bacterial Genome Sequences

  • Yoo, Wonseok;Lim, Dongbin;Kim, Sangsoo
    • Genomics & Informatics
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    • 제14권1호
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    • pp.29-33
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    • 2016
  • A retron is a bacterial retroelement that encodes an RNA gene and a reverse transcriptase (RT). The former, once transcribed, works as a template primer for reverse transcription by the latter. The resulting DNA is covalently linked to the upstream part of the RNA; this chimera is called multicopy single-stranded DNA (msDNA), which is extrachromosomal DNA found in many bacterial species. Based on the conserved features in the eight known msDNA sequences, we developed a detection method and applied it to scan National Center for Biotechnology Information (NCBI) RefSeq bacterial genome sequences. Among 16,844 bacterial sequences possessing a retron-type RT domain, we identified 48 unique types of msDNA. Currently, the biological role of msDNA is not well understood. Our work will be a useful tool in studying the distribution, evolution, and physiological role of msDNA.