• Journal of Nutrition and Health
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• v.31 no.2
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• pp.213-219
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• 1998

This study was conducted to compare and evaluate the iodide specific ion electrode method (ISE) and neutron activation analysis method (NAA) for determining iodine in human milk and cow milk. The neutron irradiation and counting operations were carried out at the TRIGA Mark-III reactor facility of the Korea Atomic Energy Research Institute. The mean concentrations of iodine in human milk samples by the ISE and the NAA were 1450$\mu\textrm{g}$/L and 1350$\mu\textrm{g}$/L, respectively. The levels were not significantly different. In cow milk samples , the mean concentrations of iodine by the ISE and the NAA were 250$\mu\textrm{g}$.L and 200$\mu\textrm{g}$/L, respectively. here, the ISE reading was significantly higher than the NAA. reading. The correlations of the two methods were 0.92(p<0.001) for human milk samples and 0.65 for cow milk samples . The coefficient of variation was 8.3% in the ISE and 4.9% in the NAA. Therefore, the iodide specific ion electrode method is sample and fast method, but probably not in processed milk since free sulfhydryl groups in milk are also detected by the iodide electrode. However, these also indicate that the ISE method may be applicable to human milk and pasteurized milk if the conventional pasteurization time-temperature relationship of standards is not exceeded. On the other hand, the NAA method , which is independent of chemical forms and matrix, can be used for determining iodine in all kinds of milk and foods.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1252_1253
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• 2009

The composites were fabricated by adding 0, 15, 20, 25[vol.%] Zirconium Diboride(hereafter, $ZrB_2$) powders as a second phase to Silicon Carbide(hereafter, SiC) matrix. The physical, mechanical and electrical properties of electroconductive SiC ceramic composites by spark plasma sintering(hereafter, SPS) were examined. Reactions between $\beta$-SiC and $ZrB_2$ were not observed in the XRD analysis The relative density of mono SiC, SiC+15[vol.%]$ZrB_2$, SiC+20[vol.%]$ZrB_2$ and SiC+25[vol.%]$ZrB_2$ composites are 90.97[%], 74.62[%], 77.99[%] and 72.61[%] respectively. The XRD phase analysis of the electroconductive SiC ceramic composites reveals high of SiC and $ZrB_2$ and low of ZrO2 phase. The electrical resistivity of mono SiC, SiC+15[vol.%]$ZrB_2$, SiC+20[vol.%]$ZrB_2$ and SiC+25[vol.%]$ZrB_2$ composites are $4.57{\times}10^{-1}$, $2.13{\times}10^{-1}$, $1.53{\times}10^{-1}$ and $6.37{\times}10^{-2}[{\Omega}{\cdot}cm]$ at room temperature, respectively. The electrical resistivity of mono SiC, SiC+15[vol.%]$ZrB_2$, SiC+20[vol.%]$ZrB_2$ and SiC+25[vol.%]$ZrB_2$ are Negative Temperature Coefficient Resistance(hereafter, NTCR) in temperature ranges from 25[$^{\circ}C$] to 100[$^{\circ}C$]. It is convinced that SiC+20[vol.%]$ZrB_2$ composite by SPS can be applied for heater above 1000[$^{\circ}C$].

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.5
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• pp.441-448
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• 2013

This paper presents the fast multipole boundary element method (FM-BEM) as a new BEM solution methodology that overcomes many disadvantages of conventional BEM. In conventional BEM, large-scale problems cannot be treated easily because the computation time increases rapidly with an increase in the number of boundary elements owing to the dense coefficient matrix. Analysis results are obtained to compare FM-BEM with conventional BEM in terms of computation time and accuracy for a simple two-dimensional steady-state heat conduction problem. It is confirmed that the FM-BEM solution methodology greatly enhances the computation speed while maintaining solution accuracy similar to that of conventional BEM. As a result, the theory and implementation algorithm of FM-BEM are discussed in this study.

• Economic and Environmental Geology
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• v.17 no.1
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• pp.35-47
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• 1984

Combined mineralogical and geochemical studies were made on two hundred eighty one representative samples from uraniferous coaly meta-pelites of the Ogcheon metamorphic terrain. Different mineral occurrence of the areas investigated should be taken into account for chemical processes for uranium extraction. Secondary uranium minerals identified are metauranocircite, metatorbernite and autunite. These are disseminated mostly on the laumontites which infused and filled secondary openings in the coaly matrix, and are often closely associated with iron oxides. The uranium distribution show distinctly log normal. Geochemical correlation coefficient of uranium and organic carbon displays +0.624~+0.796. The relationship of the major components to uranium can be expressed by the following regression equation: Log $(U_3O_8{\times}10^4)$=1.40117-0.00076 (quartz) -0.00118 (muscovite) +0.00235 (biotite) +0.00323 (other silicates) - 0.01114 (apatite) +0.01124 (hematite) +0.00149 (limonite) -0.01823 (opaques)+0.03049 (organic carbon). Uranium in the coaly meta-pelites of the Ogcheon Group was deposited together under same physico-chemical environmental conditions. There is a considerable variation in the ${\delta}^{34}S$ values (11.2~16.8 per mil) of the pyrites from the U-bearing meta-pelites, which implies sedimentary origin. The two U-bearing coaly rocks analyzed have ${\delta}^{13}C$ values between -16.88~-18.00 per mil, which suggests organic.

• Analytical Science and Technology
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• v.6 no.5
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• pp.435-442
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• 1993

Carboxymethylated polyamine-polyurea resin loaded with rubeanic acid (RCCPPI resin) was obtained by 1 step chemical reaction between chlorocarboxymethylated polyamine-polyurea(CCPPI) resin as matrix polymer and rebeanic acid. This resin was confirmed with infrared spectrometry, elemental analysis, and thermal analysis(DSC). The adsorption characteristics of the heavy metal's on the resin were studied by measuring distribution coefficient($K_d$) with changing pH of the solutions and frontal chromatography. The enrichment, recovery, and analysis of trace heavy metals, such as cadmium, cerium, copper, nikel, lead, and zinc, in the presence of high concentrations of sodium, calcium, and acetate salts was possible quantitatively by a column packed with the resin at each optimum pH. Preconcentration factors were more than 25. To elute the adsorbed heavy metals on the resin, 0.025M EDTA solution(pH 9.0) was used.

• Wind and Structures
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• v.30 no.6
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• pp.633-648
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• 2020

The objective of this work was to investigate the interference effects of two-parallel bridge decks on aerodynamic coefficients, vortex-induced vibration, flutter instability and flutter derivatives. The two bridges have significant difference in cross-sections, dynamic properties, and flutter speeds of each isolate bridge. The aerodynamic static tests and aeroelastic tests were performed in TU-AIT boundary layer wind tunnel in Thammasat University (Thailand) with sectional models in a 1:90 scale. Three configuration cases, including the new bridge stand-alone (case 1), the upstream new bridge and downstream existing bridge (case 2), and the downstream new bridge and the upstream existing bridge (case 3), were selected in this study. The covariance-driven stochastic subspace identification technique (SSI-COV) was applied to identify aerodynamic parameters (i.e., natural frequency, structural damping and state space matrix) of the decks. The results showed that, interference effects of two bridges decks on aerodynamic coefficients result in the slightly reduction of the drag coefficient of case 2 and 3 when compared with case 1. The two parallel configurations of the bridge result in vortex-induced vibrations (VIV) and significantly lower the flutter speed compared with the new bridge alone. The huge torsional motion from upstream new bridge (case 2) generated turbulent wakes flow and resulted in vertical aerodynamic damping H1^* of existing bridge becomes zero at wind speed of 72.01 m/s. In this case, the downstream existing bridge was subjected to galloping oscillation induced by the turbulent wake of upstream new bridge. The new bridge also results in significant reduction of the flutter speed of existing bridge from the 128.29 m/s flutter speed of the isolated existing bridge to the 75.35 m/s flutter speed of downstream existing bridge.

• Analytical Science and Technology
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• v.13 no.3
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• pp.304-308
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• 2000

The iodide was recovered from a simulated spent fuel to the sodium bisulfite aqueous solution. It was discussed that the trace iodide (below 1 ppm) was determined without the matrix effect of 0.1 M sodium bisulfite and 1 mM $HNO_3$ in aqueous solution by ion chromatography with UV detection. AS4A-SC (DIONEX) column and UV-absorption spectrophotometer were used. The UV-absorption spectra of sodium bisulfite, nitric acid and iodide were obtained, and then 230 nm was selected as an absorption wavelength for iodide determination. 0.1 M NaCl eluent was optimum condition. In this condition the calibration curve of iodide was obtained on the range of about 0-1,000 ppb. The linear coefficient was 0.99993 and the detection limit was 5 ppb. The relative standard deviation was 1.26%.

• Journal of KIISE
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• v.43 no.6
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• pp.686-691
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• 2016

In this paper, we introduced the adaptive spectral co-clustering, a spectral clustering for multiview data, especially data with more than three views. In the adaptive spectral co-clustering, the performance is improved by sharing information from diverse views. For the efficiency in information sharing, a co-training approach is adopted. In the co-training step, a set of parameters are estimated to make all views in data maximally independent, and then, information is shared with respect to estimated parameters. This co-training step increases the efficiency of information sharing comparing with ordinary feature concatenation and co-training methods that assume the independence among views. The adaptive spectral co-clustering was evaluated with synthetic dataset and multi lingual document dataset. The experimental results indicated the efficiency of the adaptive spectral co-clustering with the performances in every iterations and similarity matrix generated with information sharing.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.7
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• pp.531-538
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• 2017

A flush air data sensing system, which can predict flight speed, angle of attack, and angle of sideslip of the aircraft is designed and manufactured for a small UAV. Two kinds of flush pressure ports, four ports and five ports, are tapped at the same section of fuselage nose-cone. Calibration pressure data at flush ports are obtained through computations for the total aircraft by using Fluent code. Angle of attack, angle of sideslip, total pressure, and static pressure are represented with 4th-order polynomial function and calibration coefficient matrix is obtained using least square method with calibration pressure data. Flight test showed that flight speed, angle of attack, and sideslip angle predicted by four flush ports and five flush ports compared well with those by five-hole probe installed for data comparison. Especially four flush ports revealed nearly same results as those by five flush ports.

• Composites Research
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• v.17 no.6
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• pp.52-57
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• 2004

In this study, mechanical tensile properties of carbon fiber reinforced polymeric (CFRP) composite cycled with thermo-mechanical loading under cryogenic temperature (CT) were measured using cryogenic environmental chamber. Thermo-mechanical tensile cyclic loading (up to 10 times) was applied to graphite/epoxy unidirectional laminate composites far room temperature (RT) to $-50^{\circ}C$, RT to $-100^{\circ}C$ and RT to $-150^{\circ}C$. Results showed that tensile stiffness obviously increased as temperature decreased while the thermo-mechanical cycling has little influence on it. Tensile strength, however, decreased as temperature down to CT while the reduction of strength showed little after CT-cycling. For the analysis of the test results, coefficient of thermal expansion (CTE) of laminate composite specimen at both RT and CT were measured and the interface between fiber and matrix was observed using SEM images.