• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.60.2-60.2
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• 2011

This study is to develop a 1kW-class small wind turbine blade which will be applicable to relatively low speed regions. For this blade, a high efficiency wind turbine blade is designed and a light and low cost composite structure blade is adopted considering fatigue life. In this study, shape design of 1kW-class small wind turbine blade for hybrid power generation system is carried out by BEMT(blade element momentum theory). X-FOIL open software was used to acquire lift and drag coefficients of the 2D airfoils used in power prediction procedure. Moreover, pressure and velocity distributions are investigated according to TSR by CFD analysis.

• Transactions on Electrical and Electronic Materials
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• v.11 no.3
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• pp.112-115
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• 2010

This paper provides the properties of $TiO_2$ nanotube arrays which are fabricated by anodic oxidation of Ti metal. Highly ordered $TiO_2$ nanotube arrays could be obtained by anodic oxidation of Ti foil in $0.3\;wt{\cdot}%$ $NH_4F$ contained ethylene glycol solution at $30^{\circ}C$. The length, pore size, wall thickness, tube diameter etc. of $TiO_2$ nanotube arrays were analyzed by field emission scanning electron microscopy. Their crystal properties were studied by field emission transmission electron microscopy and X-ray photoelectron spectroscopy.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.60-60
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• 2014

By the pre-doping technique on graphene/copper foil, we obtained the pristine sheet resistance and optical transmittance of the chlorine doped-single layer graphene $245{\Omega}/sq$ and 97% at 550 nm wavelength, respectively. X-ray photoelectron spectroscopy revealed that an extremely high Cl coverage of 47.3% of monolayer graphene surface was achieved as the highest surface-coverage graphene doping material ever reported.

• Journal of the Korean Ceramic Society
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• v.11 no.4
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• pp.25-30
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• 1974

The mixture of quartz powder and slaked lime with plenty water was oscillated in an autoclave and treated hydrothermally under the pressure of 10 kg/$\textrm{cm}^2$ for 8 hours. The main mineral synthesized was confirmed 11$\AA$ tobermorite by the method of X-ray diffraction and selected area electron diffraction. Tobermorite was heat-treated at 40$0^{\circ}C$, 80$0^{\circ}C$ and 100$0^{\circ}C$ for investigation of transformation of morphology and structure. Electron micrographs showed the thin platy structure of synthetic tobermorite with a little of crumpled foil or fibrous semi-crystalline calcium silicate hydrates. No difference in structure was appeared under the temperature of 80$0^{\circ}C$ but tobermorite converted gradually into wollastonite at 800$^{\circ}$~85$0^{\circ}C$. On heating, moulded material from tobermorite hardly shrinks under 80$0^{\circ}C$.

• Korean Journal of Digital Imaging in Medicine
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• v.2 no.1
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• pp.92-95
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• 1996

Computed Radiography(CR) is a relatively new technology that relies on an image plate(IP) as an alternate x-ray sensor to screen/film. Standard CR cassettes do not have lead foil behind the IP to control scatter radiation. The result of this study indicate that such control is needed. In most screen/film cassettes, that lines the rear of the cassette eliminates back scatter radiation. This study was performed to Investigate on the effects of back scatter in CR images by size of exposure field, distance between the CR cassette and the wall of radiography room. 1. It showed artifacts from hinges and clips located on the back of CR cassette by back scatter radiation. 2. The greater effects of back scatter radiation in CR images was attributed to the greater size of exposure field and the longer distance between the CR cassette and the wall of radiography room.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1422-1423
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• 2007

This study deals with various neural network algorithms for the on-site partial discharge pattern recognition. For the purpose, the pattern recognition has been carried out on partial discharge data for the typical artificial defect using 9 different neural network models. In order to enhance on-site applicability, artificial defects were installed in the insulation joint box of extra-high voltage xLPE cables and partial discharges were measured by use of the metal foil sensor and a HFCT as a sensor. As the result, it is found out that the accuracy of pattern recognition could be enhanced through the application of the Sigmoid function, the Momentum algorithm and the Genetic algorism on the artificial neural networks. Although Multilayer Perceptron (MLP) algorism showed the best result among 9 neural network algorisms, it is thought that more researches on others would be needed in consideration of on-site application.

• Journal of the Korean Physical Society
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• v.73 no.10
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• pp.1546-1549
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• 2018

We have investigated core-levels of ZnO thin films at the interface with the graphene on Cu foil using in-situ X-ray Photoelectron Spectroscopy (XPS). Spectral evolution of C 1s, Zn 2p, and O 1s are observed in real time during RF sputtering deposition. We found binding energy (BE) shifts of Zn 2p and 'Zn-O' state of O 1s depending on ZnO film thickness. Core-levels BE shifts of ZnO will be discussed on the basis of electron transfer at the interface and it may have an important role in the electronic transport property of the ZnO/graphene-based electronic device.

• Journal of the Korean Chemical Society
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• v.31 no.1
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• pp.45-54
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• 1987

Dowex 1-X8 resin ion exchanged with calcon carboxylic acid (CCA-Dowex 1-X8) and 2-methyl-8-hydroxyquinoline(MHQ) impregnated-Amberlite XAD-4 resin (MHQ-XAD-4) were examined for the separation and preconcentration of ferric ion from the various matrices. The stabilities of these resins were investigated, and their capacities on ferric ion were also measured. The effect of pH on the adsorption of ferric ion and matrix ions, such as Al(Ⅲ) and Ca(Ⅱ), was investigated to determine the optimun pH ranges. Separation and preconcentration of iron in aluminium foil and mineral water samples were studied by elution method with these resin columns. The recovered ions by 10ml of 2F nitric acid was determined by flame atomic spectrophotometry. SP-Sephadex C-25 column was used to separate ferrous and ferric ion in mineral water by stepwise elution with ferrozine and 1 % ascorbic acid-ferrozine solution. The concentrated and separated each ion could be determined spectrophotometrically at the analytical wavelenth of Fe(Ⅱ)-ferrozine complex (562nm).

• Proceedings of the Korea Crystallographic Association Conference
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• 2002.11a
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• pp.5-6
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• 2002

The new spectrometer for X-ray Induced Electron Emission Spectroscopy (XIEES) .has been recently developed in KRISS in collaboration with PTI (Russia). The spectrometer allows to perform research using the XAFS, SXAFS, XANES techniques (D.C.Koningsberger and R.Prins, 1988) as well as the number of techniques from XIEES field(L.A.Bakaleinikov et all, 1992). The experiments may be carried out with registration of transmitted through the sample x-rays (to investigate bulk samples) or/and total electron yield (TEY) from the sample surface that gives the high (down to several atomic mono-layers in soft x-ray region) near surface sensitivity. The combination of these methods together give the possibility to obtain a quantitative information on elemental composition, chemical state, atomic structure for powder samples and solids, including non-crystalline materials (the long range order is not required). The optical design of spectrometer is made according to Johannesson true focusing schematics and presented on the Fig.1. Five stepping motors are used to maintain the focusing condition during the photon energy scan (crystal angle, crystal position along rail, sample goniometer rail angle, sample goniometer position along rail and sample goniometer angle relatively of rail). All movements can be done independently and simultaneously that speeds up the setting of photon energy and allows the using of crystals with different Rowland radil. At present six curved crystals with different d-values and one flat synthetic multilayer are installed on revolver-type monochromator. This arrangement allows the wide range of x-rays from 100 eV up to 25 keV to be obtained. Another 4 stepping motors set exit slit width, sample angle, channeltron position and x-ray detector position. The differential pumping allows to unite vacuum chambers of spectrometer and x-ray generator avoiding the absorption of soft x-rays on Be foil of a window and in atmosphere. Another feature of vacuum system is separation of walls of vacuum chamber (which are deformed by the atmospheric pressure) from optical elements of spectrometer. This warrantees that the optical elements are precisely positioned. The detecting system of the spectrometer consists of two proportional counters, one scintillating detector and one channeltron detector. First proportional counter can be used as I/sub 0/-detector in transmission mode or by measuring the fluorescence from exit slit edge. The last installation can be used to measure the reference data (that is necessary in XANES measurements), in this case the reference sample is installed on slit knife edge. The second proportional counter measures the intensity of x-rays transmitted through the sample. The scintillating detector is used in the same way but on the air for the hard x-rays and for alignment purposes. Total electron yield from the sample is measured by channeltron. The spectrometer is fully controlled by special software that gives the high flexibility and reliability in carrying out of the experiments. Fig.2 and fig.3 present the typical XAFS spectra measured with spectrometer.

• Journal of Conservation Science
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• v.37 no.6
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• pp.670-678
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• 2021

Anseong Cheonryongsa, a temple located in Anseong Seoun Mountain, is a part of the second Jogye Order of Korean Buddhism, under the Yongju Temple, and enshrines a gilt-bronze seated Avalokitesvara Bodhisattva. In this study, X-ray fluorescence (XRF) analysis revealed that this statue is composed of Cu-27.2 wt%, Sn-12.6 wt% and Pb-48 wt%. A gamma (γ) ray (Ir-192) image confirmed damage on the backside of the statue, which was later repaired with wood. The XRF analysis and visual observation determined the boundary between the metal and wood in the statue. In addition, results of standard X-ray peak intensity of gold foil and correlation with thickness helped to derive an equation for calculating the thickness of the Avalokitesvara Bodhisattva's gold foil. It was determined that the gilded chest (21 ㎛) and face (20.7 ㎛) of the statue were the thickest sections, the wooden substratum (11.9 ㎛) was the next-most thick, and the bronze (7.4 ㎛) was the thinnest layer.