• Korean Journal of Materials Research
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• v.24 no.10
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• pp.543-549
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• 2014

A zinc oxide (ZnO) hybrid structure was successfully fabricated on a glass substrate by metal organic chemical vapor deposition (MOCVD). In-situ growth of a multi-dimensional ZnO hybrid structure was achieved by adjusting the growth temperature to determine the morphologies of either film or nanorods without any catalysts such as Au, Cu, Co, or Sn. The ZnO hybrid structure was composed of one-dimensional (1D) nanorods grown continuously on the two-dimensional (2D) ZnO film. The ZnO film of 2D mode was grown at a relatively low temperature, whereas the ZnO nanorods of 1D mode were grown at a higher temperature. The change of the morphologies of these materials led to improvements of the electrical and optical properties. The ZnO hybrid structure was characterized using various analytical tools. Scanning electron microscopy (SEM) was used to determine the surface morphology of the nanorods, which had grown well on the thin film. The structural characteristics of the polycrystalline ZnO hybrid grown on amorphous glass substrate were investigated by X-ray diffraction (XRD). Hall-effect measurement and a four-point probe were used to characterize the electrical properties. The hybrid structure was shown to be very effective at improving the electrical and the optical properties, decreasing the sheet resistance and the reflectance, and increasing the transmittance via refractive index (RI) engineering. The ZnO hybrid structure grown by MOCVD is very promising for opto-electronic devices as Photoconductive UV Detectors, anti-reflection coatings (ARC), and transparent conductive oxides (TCO).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.12
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• pp.949-954
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• 2011

In this study, the characteristics and error ranges of the mechanical bonding strength were analyzed according to before and after thermal shock test for various chips of automotive application component using Sn-3.0Ag-0.5Cu solder. In the after thermal shock test, the mechanical bonding strengths tend to decrease, meanwhile decreasing rates of mechanical strengths were less then 12% at specimen's bonding area below 3.5$mm^2$, and were from 17 to 21% at specimen's bonding area above 12 $mm^2$. On the other hand, Specimen's mean deviation rates were about 5% at specimen's bonding area more than 12 $mm^2$. Inversely, at specimen's bonding area is less then 3.5 $mm^2$, mean deviation rates were increased to about 8%. It means that the smaller device size is, the larger mean deviation rate. In addition, error ranges and deviation rates of the mechanical bonding strengths may differ slightly depending on their bonding area. Furthermore, process conditions as well as method of mechanical reliability evaluation should be established to reduce the error ranges of bonding strength.

• Progress in Medical Physics
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• v.27 no.3
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• pp.125-130
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• 2016

Dual energy computed tomography (DECT) is used to classify two materials and quantify the mass density of each material in the human body. An energy modulation filter based DECT could acquire two images, which are generated by the low- and high-energy photon spectra, in one scan, with one tube and detector. In the case of DECT using the energy modulation filter, the filter should perform the optimization process for the type of materials and thicknesses for generating two photon spectra. In this study, Geant4 Monte-Carlo simulation toolkit was used to execute the optimization process for determining the property of the energy modulation filter. In the process, various materials used for the energy modulation filter are copper (Cu, $8.96g/cm^3$), niobium (Nb, $8.57g/cm^3$), stannum (Sn, $7.31g/cm^3$), gold (Au, $19.32g/cm^3$), and lead (Pb, $11.34g/cm^3$). The thickness of the modulation filter varied from 0.1 mm to 1.0 mm. To evaluate the overlap region of the low- and high-energy spectrum, Geant4 Monte-Carlo simulation is used. The variation of the photon flux and the mean energy of photon spectrum that passes through the energy modulation filter are evaluated. In the primary photon spectrum of 80 kVp, the optimal modulation filter is a 0.1 mm lead filter that can acquire the same mean energy of 140 kVp photon spectrum. The lead filter of 0.1 mm based dual energy CBCT is required to increase the tube current 4.37 times than the original tube current owing to the 77.1% attenuation in the filter.

• Economic and Environmental Geology
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• v.12 no.2
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• pp.79-93
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• 1979

Twenty five samples of the scheelite-powellite series from twelve Korean tungsten deposits of various geologic settings were studied mineralogically and geochemically. Variations in the trace-element contents of the scheelite minerals are considered in relation to geologic settings and mineralogic properties. Scheelites from ore deposits developed in similar geologic settings and under similar physicochemical conditions are characterized by specific combinations of trace elements.

• Journal of Conservation Science
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• v.29 no.3
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• pp.231-241
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• 2013

Analysis of the bronze bodhisattva from Pangyo-dong sites in Seongnam by computed tomography, ICP-AES, metallurgical microscope and SEM-EDS had to know manufacturing technique. And the origin of the raw material, was investigated using TIMS. Results with computed tomography, two bronze bodhisattva produced by lost-wax casting technique with hollow inside and could see the core of the inside. Result of component analysis and microstructure observation, material is alloy of copper-tin-lead and made by casting without artificial treatment. According to lead isotope ratio analysis result of bronze bodhisattva could be made into galena of the Gyeonggi massif in Korea South.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.3
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• pp.361-366
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• 2002

A. capillaris Thunberg is often used as a medicinal herb. This analysis on A. capillaris Thunberg, showing its natural ingredients and nutritive elements, is to provide a better understanding of its content and help find more various ways of use. The ingredients of A. capillaris Thunberg are as follows : 14.12% of crude protein, 4.80% of crude lipid, 2.30% of crude ash, 8.10% of crude fiber, and the rest of the ingredients are vitamins and minerals. Minerals are 3295.02 mg% of K, 2787.01 mg% of P, 1436.01 mg% of Ca, 172.32 mg% of Mg, 21.23 mg% of Fe, 18.02 mg% of Mn, 8.11 mg% of Na, 1.24 mg% of Cu, and 0.002 mg% of Sn, and vitamins are 18602.00 ug% of $\beta$-carotene and 5.82 mg% of ascorbic acid. Fatty acids in A. capillaris Thunberg are of 23.86% of oleic acids (C18:1), 46.67% of saturated fatty acids, 33.40% of monousaturated fatty acids, and 19.83% of polyunsaturated fatty acids. Oleic acid (C18:1) is the most abundant fatty acid in A. capillaris Thunberg. P/S is 0.24. A. capillaris Thunberg contains about 20 kinds of amino acid. The total amount of amino acids is 1345.29 mg%, which can be divided into 79.95% of amino acids and 13.11% of essential amino acids. This 79.95% of amino acids consist of proline, tyrosine, asparagines, glutamic acid, and valine with amount of 438.58mg%, 310.20mg%, 120.30mg%, 118.66mg%, and 88.02mg% respectively. The essential amino acid is 176.83mg%. It is shown that A. capillaris Thunberg contatins various nutrients such as minerals, vitamins, fatty acids, and amino acids, so A. capillaris Thunberg can be regarded as a highly nutritious food.

• Conservation Science in Museum
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• v.30
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• pp.23-46
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• 2023

The Jija Chongtong Gun, owned by Seokdang Museum of Dong-A University, is a tubedstyle heavy weapon of the battlefield in the mid-Joseon Dynasty and is the second largest firearm after Cheonja Chongtong. The original surface color of the Jija Chongtong Gun was obscured by foreign substances and therefore it was judged that its condition requires the conservation treatment. For stable conservation treatment, gamma ray and X-ray non-destructive transmission surveys was conducted to determine the internal structure and conservation condition. And the component analysis on the material components and surface contaminants of Jija Chongtong Gun was conducted by utilizing the p-XRF component analysis, SEM-EDS component analysis, and XRD analysis. As a result of the gamma-ray and X-ray non-destructive transmission investigation, a large amount of air bubbles was observed inside Jija Chongtong Gun, and the part that appeared to be a chaplet by visual observation was not identified. As a result of gamma-ray and p-XRF component analysis, it was confirmed that Jija Chongtong Gun was bronze made of copper (Cu), tin (Sn), and lead (Pb) alloy. As a result of surface analysis of foreign substances using SEM-EDS, it was confirmed that the main components of white foreign substances were calcium (Ca), sulfur (S), and titanium (Ti). Titanium was presumed to be titanium dioxide (TiO₂), the main component of white correction fluid. The red foreign substance was confirmed to contain barium (Ba) as its main ingredient, and was presumed to be barium sulfate (BaSO₄), an extender pigment in paint. White and red contaminants, mainly composed of titanium and barium, are presumed to have been deposited on the surface in recent years. The yellow foreign substances were confirmed to be aluminum (Al) and silicon (Si), and were presumed to have originated from soil components. As a result of SEM-EDS and XRD component analysis, the white foreign substance was confirmed to be gypsum (CaS). Based on the results of component analysis, surface impurities were removed, stabilization treatment, and strengthening treatment were performed. During the conservation process, unknown inscriptions Woo (右), Byeong (兵), Sang (上), and Yi (二) were discovered through a portable microscope and precise 3D scanning. In addition, the carving method, depth, and width of the inscription were measured. Woo Byeong Sang is located above Happo Fortress in Changwon, and Yi can be identified as the second hill.

• 한국해양학회지
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• v.24 no.3
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• pp.132-147
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• 1989

A total of 83 surface sediments and 55 sea water samples, collected from the southwestern sea of Cheju Island, were analyzed in order to understand their textural characteristics, geochemical composition and the clay mineralogical features. The sediments were subdivided into ten textural classes, namely clayey sand, slightly gravelly muddy sand, sandy clay, clay and mud. The coarse and fine-grained mixed sediments are distributed in the northern part and around the Island, whereas the fine-grained deposits are mainly distributed in the central and southern parts of the study area; small scale mud patches are distributed in the southwestern and northern parts of Cheju Island. The high concentration of total suspended matter in study area gradually increase toward the southwestern and northwestern offshore area. The concentration of geochemical elements is as follow: the content of Mn, Al, Zn, Cr, Cu and Sn increase toward the southern part which is covered mainly with fine-grained deoposits, whereas the content of Ca, Mg and Ag is higher in the northern area; the elements such as Ni, Na, Fe and Pb are more concentrated relatively in muddy deposits rather than in sandy sediments. The light minerals such as Na-Ca feldspars show a high content around the Socotra Rock, toward the Soheugsan and Cheju Islands, but the K-feldspars are relatively high around the Cheju Island. It was noticed that the provenance of these sediments is partly influenced by the geological characteristics near the island. X-ray diffractogram for clay minerals from the southeastern mud patch and around the Soheugsan Island shows the diagnostic calcite peak indicating that the greater part of these clay fraction may have been derived from present and ancient Hwangho River. The high concentration of smectite in the northern part near the Cheju and around the Soheugsan Islands, eastern side of Socotra Rock probably result from supplies smectite altered from volcanic materials distributed in the Cheju Island and Socotra Rock, whereas the samples near the Chuja and northern parts of the Cheju Island contain weak calcite peak and high concentration of kaolinite and chlorite which is closely related to the geolgical characteristics on the adjacenting land area.

• Korean Journal of Heritage: History & Science
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• v.57 no.1
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• pp.146-159
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• 2024

In this study, a study on the production technology of the Buddha statue and the production of raw material origin was conducted through scientific analysis on the Bronze seated Bodhisattva Statue of Goseongsa Temple, a treasure. As a result of microstructure analysis through a metal microscope, it was confirmed that the microstructure of the Bronze seated Bodhisattva Statue of Goseongsa Temple was a process-type dendritic structure, and the casting structure of bronze was well represented, so it was manufactured through casting. Subsequently, as a result of analyzing the alloy composition ratio through SEM-EDS, it was identified as a ternary alloy with 81.26 wt% of copper (Cu) and 16.42 wt% of tin (Sn) and 1.72 wt% of lead (Pb). The results of the analysis of lead isotope ratios using a thermal ionization mass spectrometer (TIMS) were substituted into the distribution of lead isotope ratios on the Korean Peninsula, it was shown in corresponding to Jeolla-do and Chungcheong-do regions and North and South Gyeongsang Province. This suggests that the raw materials used in their production were likely sourced from the mines around Goseong Temple in Gangjin. Despite the fact that the statue is a medium and large Buddha with a total height of 51 centimeters, 1.72 wt% of lead (Pb) was found as a result of alloy composition ratio analysis, which showed a similar composition to the lead content ratio of small bronze and gilt-bronze Buddha statues. Therefore, we compared and analyzed the results of the analysis of the composition ratio of the alloys of bronze and gilt bronze statues, which has been scientifically analyzed with a compositional age similar to that of the Bronze seated Bodhisattva Statue of Goseongsa Temple. Comparison results, Various factors, such as the size of the Buddha statue as well as its stylistic characteristics and the age of composition, may exist in determining the alloy composition ratio of the bronze and gilt bronze Buddha statues, and it was confirmed that the alloy composition ratio or casting technology was properly adjusted when the Buddha statue was created. In other words, it is judged that a more comprehensive system of Buddha statue production technology should be investigated by conducting archaeological and art history studies on stylistic characteristics and age of composition, as well as scientific analysis results such as observation of internal structure, microstructure observation, and analysis of alloy composition ratio using radiation transmission irradiation.

• Economic and Environmental Geology
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• v.39 no.1 s.176
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• pp.9-25
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• 2006

Baekun gold-silver deposit is an epithermal quartz vein that is filling the fault zone within Triassic or Jurassic foliated granodiorite. Mineralization is associated with fault-breccia zones and can be divided into two stages. Stage I which can be subdivided early and late depositional stages is main ore mineralization and stage II is barren. Early stage I is associated with wallrock alteration and the formation of sulfides such as arsenopyrite, pyrite, pyrrhotite, sphalerite, marcasite, chalcopyrite, stannite, galena. Late stage I is characterized by Au-Ag mineralization such as electrum, Ag-bearing tetrahedrite, stephanite, boulangerite, pyrargrite, argentite, schirmerite, native silver, Ag-Te-Sn-S system, Ag-Cu-S system, pyrite, chalcopyrite and galena. Fluid inclusion data indicate that homogenization temperatures and salinity of stage I range from $171.6^{\circ}C\;to\;360.8^{\circ}C\;and\;from\;0.5\;to\;10.2\;wt.\%\;eq.$ NaCl, respectively. It suggest that ore forming fluids were cooled and diluted with the mixing of meteoric water. Also, Temperature (early stage I: $236\~>380^{\circ}C,\;$ late stage $I: <197\~272^{\circ}C$) and sulfur fugacity (early stage $I:\;10^{-7.8}$ a atm., late stage I: $10^{-14.2}\~10^{-l6}atm$.) deduced mineral assemblages from stage 1 decrease with paragenetic sequence. Sulfur ($2.4\~6.1\%_{\circ}$(early stage $I=3.4\~5.3\%_{\circ},\;late\;stage\;I=2.4\~6.1\%_{\circ}$)), oxygen ($4.5\~8.8\%_{\circ}$(quartz: early stage $I=6.3\~8.8\%_{\circ}$, late stage $I=4.5\~5.6\%_{\circ}$)), hydrogen ($-96\~-70\%_{\circ}$ (quartz: early stage $I=-96\~-70\%_{\circ},\;late\;stage\;f=-78\~-74\%_{\circ},\;calcite:\;late\;stage\;I=-87\~-76\%_{\circ}$)) and carbon ($-6.8\~-4.6\%_{\circ}$ (calcite: late stage I)) isotope compositions indicated that hydrothermal fluids may be magmaticorigin with some degree of mixing of another meteoric water for paragenetic time.