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        검색결과 193

        141.
        1993.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Automated Eichner Iris Photometer(AEIP) at the Korea Basic Science Center was tested for its function and the proper procedure for photographic photometry. The AEIP requires about three hours for reaching the electrical stability. When the iris is controlled automatically, the repeatability of density unit (DU) is accurate in the uncertainty of (0.0028∼0.0048 0.0028∼0.0048 )DU. The iris reading is found to be accurate within the mean error of 0.m05 0.m05 , which could be reduced to 0.m02 0.m02 by the manual control. To check the applicability of the AEIP. each two photographic plates for UBV colors which were taken by Dupuy and Zukauskas(l976) for the open cluster Byur 2, were measured by using the AEIP. and the photographic magnitudes and colors of the stars in Byur 2 were determined. discussing the previous results.
        5,500원
        142.
        1992.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A curved channel duct is designed, built and used specifically to produce Dean vortices as a result of flow around a 180℃ curve. We present evidence using optical reflection of the existmace of the vortices in the curved section and following flat section. Also, three different feed soludons(DI water, a monodispersed styrene-divinyl-benzene latex particle suspension and a yeast suspension) were used to determine the effectiveness of Dean instabilities to destabilize polarization layers. For each suspension, the flux data were compared as a function of time for flow conditions with and without Dean vortices, for a 0.2μm microfiltration membrane. Any permeation flux improvement was not sustained for 2.0Dec due to the vortex-decay in the flat section after the curved channel, but a 15~30% permeation improvement was obtained for 3.8Dec
        4,000원
        143.
        1992.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The electrical, mechanical and optical capabilities have been tested of the microdensitometer PDS 1010GMS at the Korea Astronomy Observatory. The highest stage of scan speed 255 csu (conventional speed unit) is measured to be 47 mm/s. At this speed the position is displaced by 4 μ m to the direction of scanning and the density is underestimated by 0.4 ∼ 0.7 D . Standard deviation in the measured density is proportional to A − 0.46 , where A is the area of scan aperture. The accuracy of position repeatability is ± 1 μ m , and that of density repeatability is ± ( 0.003 ∼ 0.03 ) D . Callier coefficient is determined to be 1.37; the semispecular density is directly proportional to the diffuse density up to 3.5D. Because the logarithmic amplifier has a finite response time, the densities measured at high scan speeds are underestimated to the degree that speeds higher than 200 csu are inadequate for making an accurate astronomical photometry. After power is on, an about 5 hour period of warming is required to stabilize the system electrically and mechanically as well. On the basis of this performance test, we have determined the followings as the optimum scan parameters for the astronomical photometry: For the scan aperture 10 ∼ 20 μ m is optimal, and for the scan speed. 20 ∼ 50 csu is appropriate. These parameter values are chosen in such a way that they may keep the density repeatability within ± 0.01 D , the position displacement under 1 μ m , and the density underestimation below 0.1D even in high density regions.
        6,100원
        144.
        2019.10 서비스 종료(열람 제한)
        본 연구는 직물섬유의 배치에 따른 직물섬유 보강 콘크리트의 휨 특성을 알아보기 위하여 세 가지 변수에 대하여 휨 실험을 수행하였다. 복합체의 인장부에 근접한 위치에 직물섬유가 배치될 경우 극한하중이 증가하는 것으로 나타났다.
        145.
        2019.04 KCI 등재 서비스 종료(열람 제한)
        이 연구의 목적은 다국면 Rasch 모형을 활용하여 타당성과 신뢰성을 갖춘 국어과 수업 실연 평가 도구를 개발하는 것이다. 수업 실연 평가의 준거는 수업 전문성에 대한 개념과 수업 평가 관련 선행 연구들을 토대로 하여 ‘학습 목표와 교수-학습 과정의 연계성’, ‘교실 상호작용’, ‘교사의 언어· 행동 자질’의 3가지 하위 요인을 선정하고 그에 따른 14가지 준거의 5점 척도 평가 도구를 개발하였다. 중등 예비 국어 교사 대상의 수업 실연 평가 도구의 타당성을 검증하기 위해 국어교육과 2학년 재학생 11명을 대상으로 현직 국어 교사 4인이 수업 실연에 대한 평가를 실시하였다. 평가 결과는 다국면 Rasch 모형을 근거로 제작된 Facets Minifac을 활용하여 분석하였다. 연구 결과, 수업 실연 평가에 나타난 평가자의 엄격성 차이는 –1.34 ~ -.99 logit까지로 통계적으로 유의했으며 평가자간 신뢰도가 높은 것으로 드러났다. 또한 평가자 내 일관성은 내적합도 기준(0.5~1.5 logit)에 따라 적절한 점수를 부여하고 있음을 보였다. 수업 실연 평가 범주별 타당성에 대한 분석 결과, 난도의 차이는 통계적으로 유의하였으며(p<0.04) 피험자가 느끼는 곤란함은 모든 평가기준에서 동일하였다. 평가자와 평가기준의 편향을 분석한 결과 유의미한 편향은 도출되지 않아 평가 기준을 해석 및 적용하는 기준이 신뢰할 수 있음을 밝혔다. 평가 도구 5점 척도 적합도를 분석한 결과 2점 척도의 적합도에 다소 문제가 있으나 피험자와 평가자 수가 극히 제한적이었으므로 추후 피험자 수를 확대하여 추가 검증을 수행할 필요가 있다. 본 연구는 국어 수업 실연의 신뢰할 수 있는 객관적이고 정량적인 수업 실연 평가 도구를 개발하고 타당화함으로써 예비 국어 교사의 수업 전문성을 신장하고 학교 교육의 질적 제고를 가능하게 한다는 점에서 의의를 지닌다.
        146.
        2019.03 KCI 등재 서비스 종료(열람 제한)
        콘크리트 구조물에서 균열은 수축, 수화열 및 외부하중 등에 의해 발생하는 불가피한 현상으로, 외부 유해인자를 콘크리트 내부로의 침투를 용이하게 하여 내구성을 크게 감소시킨다. 최근 스스로 균열을 치유하는 자기치유 콘크리트에 대한 연구가 활발히 수행되고 있다. 또한 콘크리트에 발생하는 균열을 제어하여, 그 성능을 극대화하기 위한 자기치유 섬유 보강 콘크리트의 연구가 수행되고 있다. 본 연구에서는 PVA 섬유를 혼입한 자기치유 모르타르를 제작하였다. PVA 섬유 혼입율에 따른 압축강도 및 휨 성능 평가를 수행하였다. 또한, 흡수율 실험을 통해 자기치유 성능평가를 수행하였으며, 시간에 따라 균열 폭의 감소로 흡수되는 수분의 양이 감소하는 것을 확인하였다. 자기치유 생성물 분석을 통해 PVA 섬유 혼입에 의해 탄산칼슘 침전이 더 유리한 것으로 확인되었다.
        147.
        2018.10 서비스 종료(열람 제한)
        In this study, the effect on seismic performance of Binding Column Method(BCM) system was empirically evaluated. Four column models that were confined by different forces and one rare column model as a control were manufactured for cyclic loading test. As a result, in the column retrofitted with BCM, the ultimate displacement and load were increased about 2.5 and 2.0 times. Also, the energy-dissipating capacity of the retrofitted model was improved, compared to a rare column model.
        148.
        2018.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The characterization of detectors installed in space- and ground-based instruments is important to evaluate the system performance. We report the development of a detector performance test system for astronomical applications using the Andor iKon M CCD camera. The performance test system consists of a light source, monochromator, integrating sphere, and power meters. We adopted the Czerny–Tuner monochromator with three ruled gratings and one mirror, which covers a spectral range of 200–9,000 nm with a spectral resolution of ~1 nm in the visible region. Various detector characteristics, such as the quantum efficiency, sensitivity, and noise, can be measured in wide wavelength ranges from the visible to mid-infrared regions. We evaluated the Korea Astronomy and Space Science Institute (KASI) detector performance test system by using the performance verification of the Andor iKon-M CCD camera. The test procedure includes measurements of the conversion gain (2.86 e−/ADU), full well capacity (130 K e−), nonlinearity, and pixel defects. We also estimated the read noise, dark current, and quantum efficiency as a function of the temperature. The lowest measured read noise is 12 e−. The dark current at 223 K was determined to be 7 e−/s/pix and its doubling temperature is 5.3°C ± 0.2°C at an activation energy of 0.6 eV. The maximum quantum efficiency at 223 K was estimated to be 93 % ± 2 %. We proved that the quantum efficiency is sensitive to the operating temperature. It varies up to 5 % in the visible region, while the variation increases to 30 % in the near-infrared region. Based on the comparison of our results with the test report by the vendor, we conclude that our performance test results are consistent with those from the vendor considering the test environment. We also confirmed that the KASI detector performance test system is reliable and our measurement method and analysis are accurate.
        149.
        2018.05 KCI 등재 서비스 종료(열람 제한)
        최근 자기치유 재료에 대한 연구는 보수하기 힘들거나, 보수비용이 많이 소요되는 구조물에 대해 구조물 스스로 손상을 치유하여 사용수명을 증가시키기 위해 많이 수행되어오고 있다. 현재 널리 사용되고 있는 자기치유 평가 방법으로는 투수시험이 있다. 하지만, 자기치유 평가 방법에서 자기치유 성능은 콘크리트의 초기 균열 폭에 큰 영향을 받지만 일관된 기준을 가지고 있지 않은 실정이다. 따라서, 본 연구에서는 기존 연구에서 사용한 균열 폭과 투수량을 기반으로 균열 폭-투수량의 상관관계와 시간-투수량의 상관관계를 분석하였다. 또한, 광학현미 경을 이용하여 측정한 초기 균열 폭은 신뢰성이 떨어지므로 Poiseuille flow에서 α값을 도출하여 시간-균열 폭에 대한 상관관계를 분석하여 시간-투수량과 시간-균열 폭에 대한 경향을 분석하였다.
        150.
        2018.04 서비스 종료(열람 제한)
        This study was carried out on the upgrading of the noise barrier top device developed by 400km/h high speed railway infra research. By modifying the inner shape of the top device installed on noise barrier top, the performance of the first-stage top device was improved, and the weight was greatly reduced as compared with the first stage top device. In addition, the upper part was completed without an installation fixture by the integral method, and the construction was greatly improved. Finally, the upgraded top device was installed on the HONAM high speed railway site and its performance was verified.
        151.
        2018.04 서비스 종료(열람 제한)
        The purpose of this experimental study is to develop the waterborne silicon acrylic surface finishing material of parking lots. Adhesion strength experiment was conducted in order to enhance performance of the finishing material by adopting modified polyamide resin. The results qualified the standard regarding bond strength which is prescribed in KS F 4937. They are confirmed that the strength tend to increase as the amount of polyamide increased and could be an optimum surface finishing material applicable for parking lot floor.
        152.
        2018.04 서비스 종료(열람 제한)
        This paper presents the performance verification test and nonlinear analysis of reinforced concrete(RC) strut and concrete filled tube(CFT) strut using super concrete(SC; high strength concrete) for bridges. Reinforce concrete strut as well as CFT strut are poured by 80MPa characteristic strength and CFT strut are used steel pipe with 400 MPa yield strength. Test specimen are manufactured 3 types of strut that 2 types of RC strut and 1 type of CFT strut. Nonlinear finite element analysis was conducted by ABAQUS of commercial FEM software. The results of real scale test specimens are compared with the finite element nonlinear analysis output through load-displacement relation. Through this study, it was investigated that the results of the experiment and those of the analysis are adequately similar.
        153.
        2018.04 서비스 종료(열람 제한)
        In the case of railway bridges passing through the urban area, bridge type with excellent noise reduction performance is required. The bridges under development are steel composite through bridges, which is a composite structure of upper flanges with concrete, and the section bridges themselves, which surround the train, have the feature of acting as a sound barrier. In this paper, the performance test of air conduction noise is performed by the 20m full scale model test of new type steel composite through bridge.
        155.
        2017.09 서비스 종료(열람 제한)
        The purpose of this experimental study is to carry out test for the surface finishing material of parking lot using Cross-linking agent(Zinc Oxide). The specimen was fabricated by KS F 4937, Cross-linking agent 2%, 3%, 4% is mixed in water soluble acrylic resin. As a result, bond strength of surface finishing material using Zinc oxide 4% was confirmed to be superior than surface finishing material using ordinary Acrylic resin.
        156.
        2017.05 KCI 등재 서비스 종료(열람 제한)
        목적: 본 연구에서는 TOPS의 개선 버전인 스포츠 수행전략 2(TOPS 2)의 문화적으로 적합한 번역 문항을 개발하고, TOPS 2 한국판의 타당도과 신뢰도에 대한 증거를 제공하는 것이다. 방법: TOPS 2는 시합 환경에서 9개의 심리 전략(혼잣말, 감정조절, 자동적 수행, 목표설정, 심상, 활성화, 긴장풀기, 부정적 생각, 주의산만)을 평가하도록 구성되었다. 이 척도에는 주의산만이 새로운 하위요인으로 추가되었다. 스포츠 심리학과 이중 언어 전문가들이 총 9요인 36개의 시합상황 문항을 영어에서 한국어로 번역해 원본 문항과 비교했다. 또한 총 50명의 대학 운동선수들이 번역된 문항의 의미와 명확성을 검토하고 피드백을 제공했다. 한국판 TOPS 2의 구조타당성 검증을 위해 탐색적 요인분석, 확인적 요인분석을 실시하였고, 후속분석으로 내적동기(IMI)와 스포츠 불안(SAS)과의 상관분석과 주전여부에 따른 차이검증을 실시하였다. 결과: 탐색적 요인분석의 결과는 28개 문항의 8요인 구조가 적합한 것으로 나타났다. 원본 TOPS 2의 자동적 수행과 활성화 요인의 일부 문항이 단일 요인으로 합쳐져 예비 한국판 TOPS 2는 8개 요인이 되었다. 확인적 요인분석은 한국판 TOPS 2의 8요인 구조를 지지했다. 또한 추가적인 분석으로 이 버전의 신뢰도와 타당도에 대한 증거를 제시하였다. 신뢰도 분석 또한 안정성과 내적 일관성에 대한 적절한 증거를 보여 주었다. 결론: TOPS 2의 한국어 버전은 이전 TOPS 버전보다 개선되었을 뿐 아니라 심리 기술을 측정하는데 있어서 유효하고 신뢰할 수 있는 도구이다.
        157.
        2017.04 서비스 종료(열람 제한)
        PSC girder bridges, widely applied to bridge and railroad bridge (25 ~ 50 m), are a type of bridge that introduces compressive force in advance to the part where tensile force of concrete is generated. The tension force for introducing the compressive force by inserting the tendon into the concrete is a key element of the structural performance in the PSC. At present, however, measurement and verification of this is indirectly managed through deflection and cracking. However, it has become more necessary to develop practical evaluation methods of prestress force of PSC bridges. In this experiment, a small scale PSC beam with various curvature radii was made. Tension force monitoring with FBG sensor and EM sensor was performed on test members using 3 point flexural loading test. The measured values of the FBG sensors and the EM sensors used in the experiment were analyzed and compared with the measured values of the load cell.
        158.
        2017.04 서비스 종료(열람 제한)
        In the nuclear power plant, safety-related structures have been used above No. 11 rebar. It needs to mechanical connection device to join RC to SC walls because ACI 349 presents that lap splices shall not be used for bars larger than No.11 bar. The tensile performance tests were performed to confirm structural integrity on the mechanical connection device. But performing the tests in accordance with various connection cases has limitations, such as time or cost. Therefore, computational analysis methodology is developed in order to verify structural integrity for various connection cases.
        159.
        2017.01 KCI 등재 서비스 종료(열람 제한)
        PSC girder bridges, widely applied to bridge and railroad bridge (25 ~ 50 m), are a type of bridge that introduces compressive force in advance to the part where tensile force of concrete is generated. The tension force for introducing the compressive force by inserting the tendon into the concrete is a key element of the structural performance in the PSC. At present, however, measurement and verification of this is indirectly managed through deflection and cracking. However, it has become more necessary to develop practical evaluation methods of prestress force of PSC bridges. In this experiment, a small scale PSC beam with various curvature radii was made. Tension force monitoring with FBG sensor and EM sensor was performed on test members using 3 point flexural loading test. The measured values of the FBG sensors and the EM sensors used in the experiment were analyzed and compared with the measured values of the load cell.
        160.
        2016.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Scientific CubeSat with Instruments for Global Magnetic Fields and Radiations (SIGMA) is a 3-U size CubeSat that will be operated in low earth orbit (LEO). The SIGMA communication system uses a very high frequency (VHF) band for uplink and an ultra high frequency (UHF) band for downlink. Both frequencies belong to an amateur band. The ground station that communicates with SIGMA is located at Kyung Hee Astronomical Observatory (KHAO). For reliable communication, we carried out a laboratory (LAB) test and far-field tests between the CubeSat and a ground station. In the field test, we considered test parameters such as attenuation, antenna deployment, CubeSat body attitude, and Doppler frequency shift in transmitting commands and receiving data. In this paper, we present a communication performance test of SIGMA, a link budget analysis, and a field test process. We also compare the link budget with the field test results of transmitting commands and receiving data.
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