• 한국정보디스플레이학회:학술대회논문집
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• 2000.01a
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• pp.81-83
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• 2000

Tin-doped indium oxide(ITO) thin films were deposited on polyethylene terephthalate(PET) at room temperature by oxygen ion beam assisted evaporator system and the effects of oxygen gas flow rate on the properties of room temperature ITO thin films were investigated. Plasma characteristics of the ion gun such as oxygen ions and atomic oxygen radicals as a function of oxygen flow rate were investigated using optical emission spectroscopy(OES). Faraday cup also used to measure oxygen ion density. The increase of oxygen flow rate to the ion gun generally increase the optical transmittance of the deposited ITO up to 6sccm of $O_2$ and the further increase of oxygen flow rate appears to saturate the optical transmittance. In the case of electrical property, the resistivity showed a minimum at 6 sccm of $O_2$ with the increase of oxygen flow rate. Therefore, the improved ITO properties at 6 sccm of $O_2$ appear to be more related to the incorporation of low energy oxygen radicals to deposited ITO film rather than the irradiation of high energy oxygen ions to the substrate. At an optimal deposition condition, ITO thin films deposited on PET substrates showed the resistivity of $6.6{\times}10^{-4}$ ${\Omega}$ cm and optical transmittance of above 90%.

• Journal of the Korean Chemical Society
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• v.38 no.6
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• pp.411-417
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• 1994

For the analysis of fine ceramics, which is one of the new materials difficult to be dissolved, the methods of sample pretreatments such as alkali fusion and high pressure acid digestion were studied using inductively coupled plasma-atomic emission spectrometer(ICP-AES). For the Al2O3 powder sample, the results from high pressure acid digestion method showed better reproducibility than those obtained by alkali fusion technique. In the case of the analysis of SiC powder using the former method, impurities of the powder in the range of ppm were determined without matrix interference by removing Si as Si-F volatilization. Japan Certified Reference Materials (JCRM022 and JCRM023) were analyzed by this method for ultra fine powder and the results showed high accuracy and good reproducibility.

• Korean Journal of Materials Research
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• v.24 no.3
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• pp.145-151
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• 2014

Solution-based Sb-doped $SnO_2$ (ATO) transparent conductive oxides using a low-temperature process were fabricated by an electrospray technique followed by spin coating. We demonstrated their structural, chemical, morphological, electrical, and optical properties by means of X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, atomic force microscopy, Hall effect measurement system, and UV-Vis spectrophotometry. In order to investigate optimum electrical and optical properties at low-temperature annealing, we systemically coated two layer, four layer, and six layers of ATO sol-solution using spin-coating on the electrosprayed ATO thin films. The resistivity and optical transmittance of the ATO thin films decreased as the thickness of ATO sol-layer increased. Then, the ATO thin films with two sol-layers exhibited superb figure of merit compared to the other samples. The performance improvement in a low temperature process ($300^{\circ}C$) can be explained by the effect of enhanced carrier concentration due to the improved densification of the ATO thin films causing the optimum sol-layer coating. Therefore, the solution-based ATO thin films prepared at $300^{\circ}C$C exhibited the superb electrical (${\sim}7.25{\times}10^{-3}{\Omega}{\cdot}cm$) and optical transmittance (~83.1 %) performances.

• Korean journal of food and cookery science
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• v.15 no.5
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• pp.545-549
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• 1999

This study was performed to estimate mineral contents of some underground vegetables including potatoes, sweet-potatoes, carrots, radishes, onions, garlics, gingers, burdocks, and lotus roots produced in Korea using ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry). According to the measurement, the amounts of Na, Mg, Al, K, Ca, Mn, Fe, Zn, and P in underground vegetables are variable depending upon harvest time and individual plants. It was noticeable that the carrots showed quite higher amounts of Na compared to other underground vegetables. The amounts of Cd, Ba, Sr and Pb appeared to be below hazard levels. In the near future we expect that this study can be used to calculate the mineral intake from underground vegetables.

• Korean journal of food and cookery science
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• v.16 no.5
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• pp.425-430
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• 2000

This study was carried out to estimate mineral contents of some underground vegetables including potatoes, sweet-potatoes, carrots, radishes, onions, and garlics produced in Korea using ICP-AES (Inductively Coupled Plasma-Atomic Emission Spectrometry). According to the measurements, the contents of Na, Mg, Al, K, Ca, Mn, Fe, Zn, and P in Korean underground vegetables were variable depending upon producing areas and individual plants. Compared with other underground vegetables, the contents of Na in carrots and lotus roots were quite high. The contents of Cd, Ag Co. and Sr appeared to be below hazard levels. It is expected that this study can be used to calculate the mineral intake from underground vegetables.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.630-630
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• 2013

Recently, atomically smooth hexagonal boron nitride(h-BN) known as a white graphene has drawn great attention since the discovery of graphene. h-BN is a III-V compound and has a honeycomb structure very similar to graphene with smaller lattice mismatch. Because of strong covalent sp2bonds like graphene, h-BN provides a high thermal conductivity and mechanical strength as well as chemical stability of h-BN superior to graphene. While graphene has a high electrical conductivity, h-BN has a highly dielectric property as an insulator with optical band gap up to 6eV. Similar to the graphene, h-BN can be applied to a variety of field, such as gate dielectric layers/substrate, ultraviolet emitter, transparent membrane, and protective coatings. However, up until recently, obtaining and controlling good quality monolayer h-BN layers have been too difficult and challenging. In this work, we investigate the controlled synthesis of h-BN layers according to the growth condition, time, temperature, and gas partial pressure. h-BN is obtained by using chemical vapor deposition on Cu foil with ammonia borane (BH3NH3) as a source for h-BN. Scanning Transmission Electron Microscopy (STEM, JEOL-JEM-ARM200F) is used for imaging and structural analysis of h-BN layer. Sample's surface morphology is characterized by Field emission scanning electron microscopy (SEM, JEOL JSM-7100F). h-BN is analyzed by Raman spectroscopy (HORIBA, ARAMIS) and its topographic variations by Atomic force microscopy (AFM, Park Systems XE-100).

• Journal of the Korean Chemical Society
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• v.44 no.6
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• pp.547-555
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• 2000

The surface water in the upstream and midstream of Nakdong river, which is being used as tap water and industrial water supply in Daegu city and Kyungpook province, was analyzed in its water quality. In addition, the sediments of which was analyzed in terms of heavy metal and organic substance contents. All the sampling was done in the drought season for 2 days of June 22-23 and carried out in 10 sampling sites. The sites cover the whole Kyungpook provincial region, starting from Yangsam Bridge in Chyeong Ryang Provincial Park as the upper end, to the Ko Ryung Bridge as the lower end sampling site of Nakdong river that flows through Kyungpook province. The 22 items including $NH^{+}_{4}$, $NO^{-}_{2}$ and COD were analyzed for surface water and 11 items including organic constituents(trichloroethylene, etc) and heavy metals were analyzed for sediments. The sediments samples were analyzed by elution testing method and acid dissolution method and then the results were compared with each other. All heavy metals in samples were determined by Inductively Coupled Plasma-Atomic Emission Spectroscopy(ICP-AES) and other constituents were analyzed by standard testing methods of the Korean Ministry of Environment.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.1
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• pp.47.2-47.2
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• 2014

Several studies have reported the presence of sodium excess objects having neutral atomic absorption lines at $5895{\AA}$ (NaD) and $8190{\AA}$ that are deeper than expected based on stellar population models that match the stellar continuum. The origin of these lines is therefore hotly debated. van Dokkum & Conroy proposed that low-mass stars (0.3M) are more prevalent in massive early-type galaxies, which may lead to a strong NaI 8190 line strength. It is necessary to test this prediction, however, against other prominent optical line indices such as NaD, Mgb, and Fe5270, which can be measured with a significantly higher signal-to-noise ratio than NaI 8190. We identified a new sample of roughly one thousand NaD excess objects (NEOs; ~8% of galaxies in the sample) based on NaD line strength in the redshift range 0.00$H{\beta}$ line strengths and significant emission lines, which are indicative of the presence of young stellar populations. This result implies that the presence of the interstellar medium and/or dust contributes to the increase in NaD line strengths observed for these galaxies.

• Journal of the Korean Chemical Society
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• v.48 no.6
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• pp.583-589
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• 2004

In a stream of aqueous sample, trace arsenic ions were quantitatively coprecipitated and detected in ICP-AES through hydride generation. In was used as a coprecipitating reagent. The precipitate was collected on a filter and dissolved by HCl. The eluted As was sent into the reaction coil to generate hydrides and analyzed by ICP. With optimal conditions, and with a sample of 0.3 mL, an enrichment of 70 was obtained with the sampling speed of 10/hr. When compared with coprecipitation and hydride generation technique, the sensitivity was increased by 7 and 10 times, respectively. The limit of detection limit$(3{\sigma})$ was 0.020 ${\mu}g\;L^{-1}$ and the precision was 7-10%. Separation of $As^{3+}\;and\;As^{5+}$ were possible using citric acid in hydride generation.

• Journal of Adhesion and Interface
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• v.11 no.2
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• pp.70-75
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• 2010

It described the modification of polydimethylsiloxane (PDMS) with amphiphilic methyl methacrylate-based polyethylene glycol (PMMA-b-PEG) to enhance the hydrophilicity of a PDMS surface and cytotoxicity of it. PMMA-b-PEG solutions in water/ethanol mixture was spun-cast on the PDMS surface and the surface was characterized by long-term measurement of water contact angle. The morphology of PDMS surfaces coated with PMMA-b-PEG was characterized by field emission scanning electron microscopy and atomic force microscope. Cytotoxicity of the modified surfaces was investigated by MTT assay which would be necessary for the evaluation of tissue compatibility after implantation of the materials. Based on the MTT assay, PDMS coated with PMMA-b-PEG didn't show any significant cytotoxcity.