• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.104-105
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• 2020

Red mud is a highly alkaline waste by-product of the aluminum industry. Although recycling of red mud is being actively researched, a feasible technological solution has not been found yet. In this study, we propose that neutralization of red mud alkalinity could assist in its use as a construction material. Neutralized red mud ( pH 6-8) was prepared by adding sulfuric acid to liquefied red mud (pH 10-12). After adding liquid and neutralized red mud to the cement paste, the heat of hydration was measured. As a result of the experiment, the calorific value of the cement paste with liquid red mud was lowered and delayed compared to the cement paste with neutralized red mud.

• Analytical Science and Technology
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• v.12 no.2
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• pp.171-175
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• 1999

Carbon paste electrodes, modified with podands containing more than two sulfur atoms, have been employed for the voltammetric determination of Ag(I) ion from aqueous solution. The voltammetric response was characterized with respect to paste composition, preconcentration method, kind of anion, variation of pH, Ag(I) ion concentration, and possible interferences. Linear calibration curves were obtained for Ag(I) ion concentration ranging from $1.0{\times}10^{-6}$ to $9.0{\times}10^{-5}M$, and detection limit was $5.0{\times}10^{-7}M$.

• Analytical Science and Technology
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• v.15 no.1
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• pp.91-95
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• 2002

Carbon paste electrodes, modified with 5,6,14,15-dibenzo-1,4-dioxa-8,12-diazacyclopentadeca-5,14-diene containing different ligating atoms of oxygen and nitrogen, have been employed for the voltammetric determination of Ag(I) ion from aqueous solution. The voltammetric response was characterized with respect to paste composition, preconcentration method, kind of anion, variation of pH, Ag(I) ion concentration, and possible interferences. Linear calibration curves were obtained for Ag(I) ion concentration ranging from $3.0{\times}10^{-6}M$ to $8.0{\times}10^{-5}M$, and detection limit was $8.5{\times}10^{-7}M$.

• 한국정보디스플레이학회:학술대회논문집
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• 2007.08b
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• pp.1789-1791
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• 2007

We fabricated OTFT-OLED display panel by using Ag-paste for source and drains electrode of OTFTs. The OTFTs were fabricated by solution processes such as spin-coating for PVP gate dielectric and screen printing for S/D electrodes with Ag-paste, except pentacene active layer which was deposited by evaporation. The mobility was 0.024 cm2/V.sec , off state current ${\sim}10-11A$, threshold voltage 7.6 V and on/off current ratio ${\sim}105$. The panel consisted of 16 x 16 pixels and each pixel consisted of 2 OTFTs, 1 Capacitor and 1 OLED. The pixels successfully worked in terms of current magnitude supplied to OLED and the control ability of driving and switching OTFTs.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.149-150
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• 2017

It is known that physical and chemical changes of cement hydrates cause problems in the volume stability of concrete. In order to overcome these problems, there is a growing interest in research on mixing technology of cement-based materials and nanomaterials. Among the nanomaterials, carbon nanotubes (CNTs) are attracting attention due to their excellent mechanical properties. The CNTs are made of cylindrically shaped graphene sheets. According to the number of sheets, single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) are classified. Although the SWCNT has superior mechanical properties, the research using MWCNT is vigorous due to the difficulty of marketability and manufacturing, but the research using SWCNT is insufficient. In this study, we investigate the effect of SWCNT on the formation of hydrate of cement paste by observing the microstructure of broken cement paste after measuring the flexural strength of cement paste with SWCNT dispersion.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.5
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• pp.482-487
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• 2023

A carbon-based hybrid resistor was fabricated using carbon nanotube (CNT) paste as an adhesive layer to establish electrically continuous ohmic contacts between CNT sheets and different CNT sheet or copper based metal alloy plates, and its electrical properties were evaluated. CNT sheets were fabricated using vacuum filtration with a CNT solution dispersed in isopropyl alcohol (IPA) solvent. The electrical characteristics of these carbon-based hybrid resistors were investigated. The CNT paste fulfilled the requirements for forming ohmic contacts between CNT sheets and metal alloy plates, which was attributed to the lowest work function difference and excellent wettability at the interface.

• Korean Journal of Materials Research
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• v.14 no.1
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• pp.52-58
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• 2004

The surface property and formation behavior of a boride layer formed on Ni-Cr-Mo steel in a plasma paste boronizing treatment were investigated. The plasma paste boronizing treatment was carried out at 973～1273 K for 1-7 hrs under the gas ratio of Ar:H$_2$ (2:1). The thickness of the boride layer increased with increasing temperature and time in the boronizing treatment. The cross-section of the boride layer was a tooth structure and the hardness was Hv 2000～2500. XRD analysis revealed that the compound was identified as FeB, $Fe_2$B, and mixed phase of FeB/$Fe_2$B in the boride layer formed at 973～1073 K, 1173K, and 1273K, respectively. The Ni-Cr-Mo alloy boronized at 1173-1273 K showed the best excellent wear resistance against the sand. As a results of corrosion test in 1 M $H_2$$SO_4$ solution, $Fe_2$B formed on the matrix alloy exhibited higher corrosion resistance than FeB.

• Journal of the Korean Society for Heat Treatment
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• v.19 no.4
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• pp.219-224
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• 2006

Silver paste with low sintered temperature has been developed in order to apply electronic parts, such as bus electrode, address electrode in PDP (Plasma Display Panel) with large screen area. In this study, nano-sized silver particles with 10-30 nm were synthesized from silver nitrate ($AgNO_3$) solution by chemical reduction method and silver paste with low sintered temperature was prepared by mixing silver nanoparticles, conventional silver powder with the particle size 1.6 um and Pb-free frit. Conductive thick film from silver paste was fabricated by screen printing on alumina substrate. After firing at $540^{\circ}C$, the cross section and surface morphology of the thick films were analyzed by FE-SEM. Also, the sheet resistivity of the fired thick films was measured using the four-point technique.

• Journal of the Korean Ceramic Society
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• v.48 no.6
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• pp.610-616
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• 2011

The effect of curing temperature on basic geopolymeric reactivity and hardening behaviour of blast furnace slag were investigated using the mixture of pulverized slag and several alkaline solutions of relatively high concentration. For the pastes prepared at several different temperatures between 20$^{\circ}C$ and 90$^{\circ}C$, setting time and heat of reaction were examined while mineralogical and morphological examinations were performed for the hardened paste after curing period at same temperature. The geopolymeric reaction of slag was revealed to be accelerated strongly according to the curing temperature regardless of the sort and concentration of the alkaline solution. The increase of concentration of the alkaline solution within 9M and the existence of silicic ion in the solution also promoted the reaction severely. The mineral component and their ratio of the hardened paste were revealed to be influenced by the chemical species and silicic ion contained in alkaline solution rather than by the curing temperature. The higher temperature and longer period of curing stage were effective for the sustained formation of geopolymer and succeed improvement of density and uniformity of morphology of the final hardened body.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.71-72
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• 2012

The purpose of this study is not only fixation of carbon dioxide using the cement-Paste solution's calcium ion by wet carbonating reaction but also quantitatively evaluate the possibility of storage technology of Carbon dioxide. wet carbonation is reaction of CO₂ injection by CO₂ reactor. As a result of experiment, the carbon dioxide is fixed, and high-purity Calcium Carbonate is eluted.