• The Journal of the Korean dental association
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• v.55 no.2
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• pp.128-138
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• 2017

Objective: The aim is to evaluate the potential of the mesiodens through the comparative inorganic analysis of 3rd molar teeth prior to clinical study. Material and methods: The extracted mesiodens and the 3rd molar teeth were prepared. The teeth are prepared as in the process of the autogenous tooth bone graft. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) analysis was performed for inorganic analysis. Results: Rough and porous surfaces were observed in all materials in SEM analysis. Ca/P ratio of mesiodens was 1.55 and the 3rd molar was 1.22 in EDS analysis. XRD analysis shows that the 3 main peaks position were similar. This means that the graft materials are very similar to that of the crystallinity. Conclusions: The mesiodens and the 3rd molar teeth are very similar to the inorganic component. These results provide the reasonable rationale that mesiodens can be used as autogenous tooth bone graft in a clinic.

• Journal of Conservation Science
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• v.17 s.17
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• pp.57-64
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• 2005

In the course of examining the micro structure of Iron chisel and Iron arrowhead, a relics of the 16th or 17th of Chosun Dynasty unearthed at near Gangsun-tower, Chengpyeong temple. Collected un-eroded samples from the relics were looked into the metallic structure through optical metallography. Non-metallic inclusions were-analysed by SEM and EDS. The micro structure examination and SEM-SDS analysis revealed that Iron chisel and Iron arrowhead had been produced from the sponge iron close to pure iron made by low temperature reducing in a solid and then the surface carbon content was increased by carburizing treatment. It was also found that Iron chisel had been hardened through the repetitive processes of quench hardening and heat treatment, after increasing carbon content to a certain level. Up to now, there have been a number of studies in the domestic academia which were studied mainly on the structure of metallic relics in the period of the Three Kingdoms or before. Although this research was limited in type and number of the relics, it turned out to be interesting in that it revealed the 16th or 17th century way of processing iron, even in fragments. It is thought to be fruitful that iron had been made even in the Chosun Dynasty from the sponge iron.

• Polymer(Korea)
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• v.31 no.6
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• pp.461-468
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• 2007

In order to understand the structure of the existing aggregate in the nanocomposite, which has been prepared with polyester and trisilanolisobutyl polyhedral oligomeric silsesquioxane(TBPOSS), laser light scattering(LLS) and SEM-EDS were applied to its 1,1,1,3,3,3-hexafluoro-2-propanol solution and original sample, respectively. Although aggregate particles appeared as spherical shape of the average diameter of 120 nm in SEM image, they were not microgels but almost linear copolymer chains ($M_w=2.3{\times}10^6\;g/mol$) alternating 320 molecules of TBPOSS with polyester subchains. It has been microphase-separated from the matrix polyester due to the difference of chemical composition. As the matrix, polyester chain of $M_w=4.0{\times}10^4\;g/mol$ had averagely 2.5 molecules of TBPOSS per chain. It is also found that about 93% of total TBPOSS molecules existed in matrix phase and the residual 7% in spherically aggregated phase.

• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.5
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• pp.548-557
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• 2015

This paper is results on Chemisorption of organic compound for the sea water fire fighting line of naval vessels. The quantitative analysis of Chemisorption has been investigated in seawater after immersion in 0.1 % of NaDDTC solutions for 43 hours. The morphology and topography were investigated by FE-SEM and AFM. The chemical elements were analyzed by SEM-EDS, XPS and the depth of chemical elements was measured by depth profiles. The effect of NaDDTC comes from Chemisorption between Copper and Sulfur of NaDDTC. As a result, test results showed that sulfur is helpful to protect a corrosion of seawater line.

• Economic and Environmental Geology
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• v.52 no.6
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• pp.595-604
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• 2019

The purpose of this study was simply to obtain gold through a microwave-nitric acid experiment of invisible gold concentrate with the use of filter paper. For the purpose, this study conducted a microwave-nitric acid leaching experiment and examined nitric acid concentration. As a result of the experiment, this study discovered that Fe, Te and Ag were completely leached in the leaching solution whereas Au was not determined in all of the nitric acid conditions. The leaching solution was filtered with three filter papers and then these filter papers were analyzed with SEM/EDS. As a result of the EDS analysis, Au was detected in all of the surface and cross-section of the 1st, 2nd and 3rd filter papers. As the three filter papers containing solid-residue were analysed in the lead-fire assay, gold particles were found in all of the nitric acid conditions. In the lead-fire assay, maximum gold(452.50g/t) was recovered when nitric acid concentration was 6M and microwave leaching time was 12mins.

• Korean Journal of Materials Research
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• v.27 no.7
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• pp.386-391
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• 2017

Using a customized diffusion bonder, we executed diffusion bonding for ring shaped white gold and red gold samples (inner, outer diameter, and thickness were 15.7, 18.7, and 3.0 mm, respectively) at a temperature of $780^{\circ}C$ and applied pressure of 2300 N in a vacuum of $5{\times}10^{-2}$ torr for 180 seconds. Optical microscopy, field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS) were used to investigate the microstructure and compositional changes. The mechanical properties were confirmed by Vickers hardness and shear strength tests. Optical microscopy and FE-SEM confirmed the uniform bonding interface, which was without defects such as micro pores. EDS mapping analysis confirmed that each gold alloy was 14K with the intended composition; Ni and Cu was included as coloring metals in the white and red gold alloys, respectively. The effective diffusion coefficient was estimated based on EDS line scanning. Individual values of Ni and Cu were $5.0{\times}10^{-8}cm^2/s$ and $8.9{\times}10^{-8}cm^2/s$, respectively. These values were as large as those of the melting points due to the accelerated diffusion in this customized diffusion bonder. Vickers hardness results showed that the hardness values of white gold and red gold were 127.83 and 103.04, respectively, due to solid solution strengthening. In addition, the value at the interface indicated no formation of intermetallic compound around the bonding interface. From the shear strength test, the sample was found not to be destroyed at up to 100,000 gf due to the high bonding strength. Therefore, these results confirm the successful diffusion bonding of 14K white-red golds with a diffusion bonder at a low temperature of $780^{\circ}C$ and a short processing time of 180 seconds.

• Journal of Electrical Engineering and Technology
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• v.1 no.2
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• pp.246-250
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• 2006

Highly ordered gold nanodot arrays have been successfully obtained by vacuum evaporation using an anodic aluminum oxide (AAO) as a shadow mask. An AAO mask with the thickness of 300 um was prepared through an anodization process. The structure of the nanodot arrays was studied by a field- emission scanning electron microscope (FE-SEM) equipped with an energy dispersive spectrometer (EDS). A tapping mode atomic force microscope (AFM) was employed for studies of height and phase feature. The nanodot arrays were precisely reproduced corresponding to the hexagonal structure of the AAO mask in a large area. In the gold nanodot arrays, the average diameter of dots is approximately the same as the AAO pore size in the range from 70 um to 80 nm and 100 nm center-to-center spacing. EDS analysis indicated that the gold dots were almost entirely consisted of gold, a highly demanded material.

• 열병합발전
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• s.30
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• pp.21-25
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• 2002

According to recent Korea Electric Power Company report, yearly distribution line brass cramp bolts failure summed up to 4,400 cases emerging as one of main local break-down causes. Naturally, the need for the investigation was proposed To determine the root cause of the cramp bolt failures, mechanical and metallurgical investigation were performed for 90 samples which collected from various sites. For the understanding of the geometric characteristics, stress distribution was evaluated by CAE program and proof load of each bolts was tested. The SEM&EDS was used for metallurgical investigation. Through the investigation, the root causes of failures were confirmed. All damaged bolts showed intergrannular fracture mode and the all fractured bolt showed ß phase morphology contrast to the a&ß mixture morphology of the non-damaged samples. Additionally, EDS analysis confirmed the existence of lead rich layer on grain boundaries.

• Fire Science and Engineering
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• v.34 no.2
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• pp.54-63
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• 2020

Although fires caused by heat generation due to Cu₂O breeding in wire connections are well-known among fire investigators, there are few papers on the analysis and introduction of fire cases by heat generation due to Cu₂O breeding. This study analyzed fire statistics caused by heat generation in electrical connections and the phenomena and features of heat generation due to Cu₂O breeding. Then, a fire which occurred in the wire connection in a university lab by heat generation due to Cu₂O breeding was analyzed in more detail. This fire case could reach a conclusion that heat generation due to Cu₂O breeding caused a fire in the wire connection through the fire pattern investigation of fire origin, the visual investigation of wire connection, 3D CT, power-on-test, and stereoscopic microscopy, SEM and EDS analysis.

• Journal of Conservation Science
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• v.18 s.18
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• pp.5-18
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• 2006

Dujeong-dong site of Cheonan is known as the site of Baekje period in the first half of the fourth century. This study investigated the visible properties and the chemical composition of the 18 pieces of the glass found in the site, and considered scientific properties and periodic interrelationship of the glass on the basis of the analysis result. The observation of the visible properties and microstructure of ancient glass was performed with both an electron microscope and an optical microscope, and the chemical composition was conducted by way of both quantitative and qualitative analysis using Scanning Electron Microscope(SEM) with Energy Dispersive Spectrometer(EDS). In the analysis result, various chemical composition systems are identified in the glass beads of Dujeong-dong site, such as lead-barium, soda and potash glass, and also different shapes were found such as gold foil glass beads, tubular beads, and round beads. It is estimated that the classification of glass by means of its chemical composition was also closely related to the color of glass.