• Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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• 2001.06a
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• pp.1171-1171
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• 2001

Quantitative analysis is an important requirement in exploration, mining and processing of minerals. There is an increasing need for the use of quantitative mineralogical data to assist with bore hole logging, deposit delineation, grade control, feed to processing plants and monitoring of solid process residues. Quantitative analysis using X-Ray Powder Diffraction (XRD) requires fine grinding and the addition of a reference material, or the application of Rietveld analysis to XRD patterns to provide accurate analysis of the suite of minerals present. Whilst accurate quantitative data can be obtained in this manner, the method is time consuming and limited to the laboratory. Mid infrared when combined with multivariant analysis has also been used for quantitative analysis. However, factors such as the absorption coefficients and refractive index of the minerals requires special sample preparation and dilution in a dispersive medium, such as KBr to minimize distortion of spectral features. In contrast, the lower intensity of the overtones and combinations of the fundamental vibrations in the near infrared allow direct measurement of virtually any solid without special sample preparation or dilution. Thus Near Infrared Spectroscopy (NIR) has found application for quantitative on-line/in line analysis and control in a range of processing applications which include, moisture control in clay and textile processing, fermentation processes, wheat analysis, gasoline analysis and chemicals and polymers. It is developing rapidly in the mineral exploration industry and has been underpinned by the development of portable NIR spectrometers and spectral libraries of a wide range of minerals. For example, iron ores have been identified and characterized in terms of the individual mineral components using field spectrometers. Data acquisition time of NIR field instruments is of the order of seconds and sample preparation is minimal. Consequently these types of spectrometers have great potential for in-line or on-line application in the minerals industry. To demonstrate the applicability of NIR field spectroscopy for quantitative analysis of minerals, a specific example on the quantification of lateritic bauxites will be presented. It has been shown that the application of Partial Least Squares regression analysis (PLS) to the NIR spectra can be used to quantify chemistry and mineralogy in a range of lateritic bauxites. Important, issues such as sampling, precision, repeatability, and replication which influence the results will be discussed.

• Journal of electromagnetic engineering and science
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• v.17 no.3
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• pp.113-119
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• 2017

The application of compressive sensing (CS) to a radar imaging system based on a frequency-scanned microstrip leaky wave antenna is investigated. First, an analytical model of the system matrix is formulated as the basis for the inversion algorithm. Then, $L_1-norm$ minimization is applied to the inverse problem to generate a range-azimuth image of the scene. Because of the antenna length, the near-field effect is considered in the CS formulation to properly image close-in targets. The resolving capability of the combined frequency-scanned antenna and CS processing is examined and compared to results based on the short-time Fourier transform and the pseudo-inverse. Both simulation and measurement data are tested to show the system performance in terms of image resolution.

• Proceedings of the Korea Contents Association Conference
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• 2006.05a
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• pp.398-400
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• 2006

The symplectic form based on a symplectic space is introduced to simplify a probe compensation equation in terms of the near-field measurement algorithm. The Lorentz reciprocity principle is also utilized for a near-field probe compensation equation. Applying the symplectic form to the probe compensation equation gives a simplified probe equation, thus confirming the validity of our approach.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05a
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• pp.137-141
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• 2004

저항특성이 다른 ITO박막의 구조특성과 표면특성을 XRD와 AFM(atomic force microscopy), SEM(scanning electron microscopy)을 이용하여 관측하였다. 접촉방식인 4단자 법을 사용하여 ITO박막의 표면전기저항을 측정하였다. 관측된 구조 및 표면특성을 바탕으로 비파괴 비접촉방식을 이용한 근접장 마이크로파 현미경을 이용하여 얻은 ITO박막의 표면저항특성과 비교 연구하였다.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.111.2-111
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• 2001

The research focuses on controlling a gap to measure the surface defect in semi-conductor fabrication device. The measurement is available accompanying a near field image gap control. In this article, a pneumatic servo system is adopted for the near field gap control. The advantage of the pneumatic servo system is on the preventing the possibility of contacting the device to the wapper surface, fence arising fatal damage. Furthermore, the air from the pneumatic system blows the some particle on the wapper during controlling. The target gap is less than 20 $\mu$m and the gap should keep same amount while the device moves around the surface. The experiment by the pneumatic servo control system is done by employing a simple PID control, and the tracking performance is remarkably verified. The target gap is set from 10 $\mu$m to 100 $\mu$m ...

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.11
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• pp.20-24
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• 1997

We have successfully fabricated high power (~20W) laser diode array, which are useful for pumping Nd:YAG lasers. The laser diode aray has 20 100.mu.m-wide cahnnels of which space was adjusted to 350.mu.m to improve thermal characteristics. And channel width is 100.mu.m. For an uncoated LD array, the output power of 15.66W has been obtained at 41A under quasi-CW operation, which results in about 0.42W/A slope efficiency. After aR(5%) and HR (95%) coatings on both facets, the output power was improved up to 21.18W at 40A under the same operation as above and the slope efficiency was 0.795W/A. On the other hand, by using a near field measurement system consisting of objective lens, eyepiece, CCD camera and image processing board, the typical near field patten of 1*20 LD array was observed.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1743-1744
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• 2008

NSOM(Near-field Scanning Optical Microscopy) 조화 진동자(Tuning fork)와 광섬유 탐침을 결속시켜 미소신호를 검출하여 증폭과 잡음을 제거하기 위한 Pre-amplifier의 설계 및 제작과 더불어 시료-탐침간 거리를 파장보다 짧게 유지시키는 Shear force 검출, 효율적인 시료-탐침 거리유지 알고리즘 구연 및 탐침을 시료 표면에서 일정한 거리를 안정적으로 유지하도록 제어 및 시료의 높이 정보를 얻어내는 시스템을 설계 및 제작하였다. 또한 ����$CO_2Laser$를 이용한 Heat Pulling 장치개발을 통해 탐침을 제작, LabVIEW를 통해 개별적인 시스템을 하나로 통합하여 AFM 테스트 시료인 SiO 샘플의 표면 형상을 측정하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.5
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• pp.601-610
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• 1986

The acoustic intensity in the very near field of a vibrating surface reveals information about the location of sound sources and sinks. A system model of tennis racket was developed from simultaneous measurement of excitation force, surface vibration and the near field sound pressure. The characteristics of structural dynamics were obtained by standard experimental modal analysis techniques while the sound radiation characteristics were determined by estimating the acoustic intensity. In this paper, the information about vibration behviour was obtained by acoustic intensity method and some, experiments for verification were carried out. Close correlation was found between experimentally determined acoustic intensity and vibration mode patterns of the tennis racket.

• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1908-1910
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• 1997

The electric and magnetic fields (EMFs) near 345/154 kV overhead transmission lines were measured. The average values of maximum electric field and magnetic field for 44 transmission lines were 1.11 kV/m and 24.5 mG, respectively. These values were lower than any standards of advanced countries. The EMFs of distribution lines and substation, and electric appliances were also measured and compared with those of transmission lines.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.24-41
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• 2007

In this paper several recent case studies of near surface geophysical applications in Greece are presented. The case studies are focused mostly in archeological site investigation, a field which is of high interest in Greece due to its reach historical heritage. The growing construction works in several parts of Greece as well as the increasing public interest in exploring and preserving cultural heritage lead to an increase of the application of nearsurface geophysics techniques as a preliminary investigation tool prior to engineering and archeological excavation works. Research efforts, presented in this work, are focused to extending and adapting standard nearsurface techniques in order to be made more effective for archaeological site investigation. The presented case studies involve not only standard field investigation procedures but also novel approaches such as the use of non-spike electrodes, efficient measuring and instrumentation strategies, unusual configurations and measurement environments. Overall it shown that efficient and state-of-art nearsurface geophysical techniques used for archaeological prospection purposes provide significant archaeological and structural information valuable for archeologists, engineers and conservation scientists.