• 자원리싸이클링
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• 제26권2호
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• pp.3-10
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• 2017

희토류 원소는 첨단 산업용 소재의 구성 성분으로 고순도가 요구된다. 국내산 monazite광과 Ni-MH전지는 경희토류를 함유한 자원이다. 이러한 자원을 염산으로 침출한 용액에서 경희토류성분을 용매추출로 분리하는 공정에 대해 고찰하였다. 양이온 추출제와 3차 아민의 혼합추출제로 경희토류를 추출시 상승효과가 있으며 pH 감소가 둔화된다. 혼합추출제 사용시 수상의 pH가 금속의 추출 및 상승효과에 미치는 영향을 분석하였다. 향후 양이온과 아민의 혼합추출제에 의한 경희토류 분리공정을 개발하기 위해서는 mixer-settler의 조업 자료 확보가 필요하다.

• 한국산업융합학회 논문집
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• 제22권6호
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• pp.637-647
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• 2019

In this study, we analyzed seismic behavior of reinforced earth retaining wall through the model test in order to characterize the behavior of reinforced earth retaining wall during earthquake. A scale model test was performed based on similitude ratio in accordance with law of similitude due to time and financial constraints on real scale modeling experiments. Seismic resistance characteristics of each seismic waves were analyzed by assessing the variations measured through excitation of the excited acceleration of 0.05g, 0.1g, 0.15g, and 0.2g. The results of this study, it would be important to obtain reasonable and abundant data on ground properties and seismic design in preparation for earthquakes when assessing the safety of block type reinforced earth retaining wall confined to model experiment. Acquisition of those data and systematic analytical techniques are considered likely to have a significant effect on the decrease of structure damage caused by earthquakes in Korea which has recently witnessed frequent occurrence of earthquakes.

• Computers and Concrete
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• 제33권5호
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• pp.481-496
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• 2024

Internal erosion around pipes can lead to the failure of earth dams through various mechanisms. This study investigates the displacement patterns in earth dam models under three different failure modes due to internal erosion, using digital image correlation (DIC) methods. Three failure modes—erosion along a pipe (FM1), pipe leakage leading to soil erosion (FM2), and erosion in a pipe due to defects (FM3)—are analyzed using two- and three-dimensional image- processing techniques. The internal displacement of the cross-sectional area and the surface displacement of the downstream slope in the dam models are monitored using an image acquisition system. Physical model tests reveal that FM1 exhibits significant displacement on the upper surface of the downstream slope, FM2 shows focused displacement around the pipe defect, and FM3 demonstrates increased displacement on the upstream slope. The variations in internal and surface displacements with time depend on the segmented area and failure mode. Analyzing the relationships between internal and surface displacements using Pearson correlation coefficients reveals various displacement patterns for the segmented areas and failure modes. Therefore, the image-based characterization methods presented in this study may be useful for analyzing the displacement distribution and behavior of earth dams around pipes, and further, for understanding and predicting their failure mechanisms.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2004년도 Proceedings of ISRS 2004
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• pp.594-597
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• 2004

The ground subsidence that occurred in an abandoned coal mining area, Gaeun, Korea, was observed by using 25 JERS-1 SAR interferograms from November 1992 to October 1998. We estimated the subsidence on a subset of image pixels corresponding to point-wise permanent scatters (PSs) by exploiting a long temporal series of interferometric phases. The results were compared it with a distribution map of in situ examined crack level. PSs were identified by means of amplitude dispersion index and coherence of the interferograms. The measured subsidence rate represented the average velocity in a period of image acquisition and excluded complex nonlinear displacements such as an abrupt collapse. The mean line-of-sight velocity in the study area is 0.19cm/yr and an r.m.s. error is 0.18cm/yr. The center of the abandoned Gaeun coal mine (0.49cm/yr) and the area near to the Gaeun station (1.66cm/yr) were observed as most rapidly subsiding areas.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2002년도 Proceedings of International Symposium on Remote Sensing
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• pp.428-428
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• 2002

The scientific objectives of PACRIM (Pacific Rim) are to advance the understanding of polarimetric and interferometric radar and to promote its application in environmental research designed to detect and quantify changes found in both the physical and humanly dominated ecosystems on the earth's surface. The information derived is used to more readily identify environments at risk; improve environmental decision making and the management of resources and thereby lead to the implementation of more effective and sustainable land use practices. PACRIM is a collaborative research project was organized by NASA's Mission to Planet Earth, Airborne Sciences Program; the Jet Propulsion Laboratory; CSIRO-COSSA and the Centre for Remote Sensing and GIS at the University of New South Wales. A decade of working with AIRSAR data (1993-2003) in the Australia-Asian-Pacific region has provided the opportunity for more than 400 investigators from 20 countries to collect, analyse, interpret and apply state-of-the-art radar data to earth-science studies. This has been achieved by scientists working within seven broad research themes; o Forestry and vegetation o Geology and tectonic processes o Interferometry o Disaster management o Coastal analysis o Agriculture o Urban and regional development. This paper presents an overview of the three data acquisition missions (1993,1996 and 2000) and the science research outcomes achieved from analyzing high quality radar data.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2005년도 공동학술대회 논문집
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• pp.293-298
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• 2005

본 연구에서는 트랜스듀서를 이용하여 탐사 장소, 수심 및 목적에 따라 사용 할 수 있고 운용 및 이동이 편리한 천해저용 탄성파 음원을 제작하였으며, 다중채널 해양탄성파 탐사를 하기 위해 4채널 스트리머 2개를 제작하였다. 또한 분해능을 향상하기 위하여 24bits A/D 변환기를 사용하였고, 채널이 총 8개인 다중채널 기록장치를 제작하여 자료취득 과정에 있어서 효율성을 높이면서 자료의 품질을 향상시켰다. 개발된 시스템의 현장 적용성을 검증하기 위하여 기존의 상용화 자료 취득시스템으로 현장탐사를 동시에 수행하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2003년도 ICCAS
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• pp.876-881
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• 2003

Reliable attitude estimation during the launch and early orbit phase is a critical issue for a satellite. Typically gyroscopes and other sensors are utilized to estimate the attitude during this phase. It is difficult to estimate the attitude quickly and reliably using gyroscopes because it requires a large computational load and accurate sensor measurements. Furthermore, the gyroscope failure may lead to the loss of the satellite. This paper suggests a simple attitude estimation method of a low earth orbit satellite without using gyroscopes, but only using sun sensors and magnetometers in the sun-acquisition mode. Using Kompsat-I telemetry data, we verified that the suggested algorithm provides attitude estimation within 3 degrees on each axis.

• 항공우주기술
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• 제4권2호
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• pp.60-64
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• 2005

과학기술위성 2호의 주요 임무는 주 탑재체인 마이크로웨이브파 라디오미터(DREAM: Dual-channel Radiometers for Earth and Atmosphere Monitoring)개발, 부 탑재체인 레이저 반사경(SLR: Satellite Laser Ranging) 개발, 그리고 위성체 핵심기술 선행연구를 위한 Frame-Type 위성구조체, 복합소재 태양전지판, Dual-Head 별추적기, CCD 태양센서, 펄스형 플라즈마 추력기, 소형 탑재 컴퓨터 및 고속 X-band 송신기 개발 등을 포함한 100kg급 저궤도 소형위성 개발이다. 본 논문에서는 과학기술위성 2호 시스템에 대하여 설명을 한다. 과학기술위성 2호의 시스템 정의 및 기본적인 운영개념, 과학기술위성 2호의 주 탑재체인 마이크로웨이브파 라디오미터, 부 탑재체인 레이저 반사경, 그리고 이들을 지원하기 위한 위성본체 등을 포함한다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2007년도 Proceedings of ISRS 2007
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• pp.219-222
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• 2007

Today, use of high resolution satellite image with at least 1m resolution is expanding into many more areas including forest, river way, city, seashore and so forth for disaster prevention. Interest in this medium is increasing among the general public due to the roll-out to the private sector as Google earth, Virtual Earth and so forth. However, pre-processing process that revises the geometrical distortion that result at the time of photographing is required in order to use high resolution satellite image. The purpose of this research is to search the most accurate GCP(Ground Control Point) information acquisition method that is used for the revision of high resolution satellite image's geometrical distortion through automated processing. Through this, it is possible to contribute to increasing the level of accuracy at the time of high resolution satellite image revision and to secure promptness.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2003년도 Proceedings of ACRS 2003 ISRS
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• pp.1052-1054
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• 2003

RAZAKSAT is a second micro-satellite mission by Malaysian Satellite Program and is expected for launch in June 2004. Designed to orbit the earth at low-equatorial orbit, RAZAKSAT will meet Malaysia’s immediate needs to rapid data acquisition (real time and more repetitions) to address many operational issues of remote sensing applications, which require availability of current data sets. RAZAKSAT will be among the first remote sensing satellite to orbit the earth at low inclination along the equator, 9$^{\circ}$ with 685km altitude, hence, allows optimal geographical information and environment change within equatorial region be observed with a unique revisit characteristics. The satellite primary payload is MAC, a push-broom type camera with 2.5m of ground sampling distance (GSD) in panchromatic band and 5m of GSD in four multi-spectral bands. This paper describes on the variation of illumination anticipated from simulated RAZAKSAT image, examine its implication to its ground leaving radiances for major applications.