• 한국응용과학기술학회지
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• 제26권4호
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• pp.467-472
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• 2009

Ultraviolet curable coating solution was prepared with poly(ethylene glycol) acrylate oligomer and various mono and multi-functional acrylate monomers. The optical properties of UV cured coating layer on PET film with acrylate coating solution containing metal oxides, such as fumed silica and alumina, were also investigated to reduce light reflection on films. Poly(ethylene glycol) diacrylate which has 575 of average molecular weight was used as oligomer acrylate, and pentaerythritol triacrylate and dipentaerythritolpenta-/hexa acrylate were used as multi-functional acrylate monomers. Also, butyl acrylate was used to improve the adhesion as well as to reduce glass transition temperature to give a better flexability. 1-hydroxy cyclohexyl phenyl ketone was used as photoinitiator. We found out the metal oxides in acrylate coating solution showed a homogeneous dispersion from energy dispersive spectroscopy data. Transmittance and light reflection of coated PET film was measured with UV/vis spectrometer and gloss meter, respectively. When 1.00 g of both metal oxides was added into coating solution, the transmittance and the glossiness were reduced from 90% to 30% and from 190 GU to 35 GU, respectively. However, adding up to 1.00 g of the metal oxide into coating solution did not affect on the hardness of coating layer and adhesion between coated layer and PET film. Conclusively, we can control transmittance and light reflection of coated film by adjusting the amounts of metal oxide in coating solution.

• 센서학회지
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• 제29권6호
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• pp.365-368
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• 2020

As a green and abundant source of energy, H2 has attracted the attention of researchers for use in different applications. Nevertheless, it is highly flammable, and because of its significantly small size, extreme attention is needed to detect its leakage. In this review, we discuss different effects of noble metals on the H2 gas response and performance of metal oxide-based gas sensors. In this regard, we discuss the effects of noble metals, in combination with metal oxides, on H2 gas detection. The catalytic activity towards H2 gas and the formation of heterojunctions with metal oxides are the main contributions of noble metals to the sensing improvement of H2 gas sensors. Furthermore, in the special case of Pd and somewhat Pt, the formation of PdHx and PtHx also affects the H2 sensing performance. This review paper provides useful information for researchers working in the field of H2 gas detection.

• Corrosion Science and Technology
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• 제7권2호
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• pp.112-118
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• 2008

We observed initial rusting process of steel containing Al under wet/dry cyclic condition with NaCl solution film using in situ X-ray diffraction spectroscopy at SPring-8 synchrotron radiation facility. It was found that mass fraction of iron oxides such as ${\alpha}-FeOOH$, ${\beta}-FeOOH$ and ${\gamma}-FeOOH$ varied with Al content. Some kinds of Al oxides were also found at the initial stage of corrosion. Those corrosion products might affect the corrosion process and corrosion rate of the steel.

• Corrosion Science and Technology
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• 제7권4호
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• pp.237-242
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• 2008

Physical properties of water, such as dielectric constant and ionic product, significantly vary with the density of water. In the supercritical conditions, since density of water widely varies with pressure, pressure has a strong influence on physical properties of water. Dielectric constant represents a character of water as a solvent, which determines solubility of an inorganic compound including metal oxides. Dissociation equilibrium of an acid is also strongly dependent on water density. Dissociation constant of acid rises with increased density of water, resulting in drop of pH. Density of water and the density-related physical properties of water, therefore, are the major governing factors of corrosion and environmentally assisted cracking of metals in supercritical aqueous solutions. This paper discusses importance of "physical properties of water" in understanding corrosion and cracking behavior of alloys in supercritical water environments, based on experimental data and estimated solubility of metal oxides. It has been pointed out that the water density can have significant effects on stress corrosion cracking (SCC) susceptibility of metals in supercritical water, when dissolution of metal plays the key role in the cracking phenomena.

• 센서학회지
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• 제31권4호
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• pp.187-193
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• 2022

The accurate detection of environmental and biomarker gas species has attracted increasing attention due to their broad applications, such as air quality monitoring, disease diagnosis, and explosive chemicals detection. To accurately detect target gas species using chemiresistive gas sensors, using nanocatalysts on semiconducting metal oxides (SMOs) is considered the most promising approach. This review summarizes recent studies on methods for nanocatalysts functionalization on SMOs to achieve the highly selective gas sensors. To this end, we discuss various nanocatalyst decorated metal oxide-based chemiresistive gas sensors and provide an insight to construct highly accurate gas sensors.

• Applied Science and Convergence Technology
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• 제23권1호
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• pp.14-26
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• 2014

Copper is an important component from coin metal to electronic wire, integrated circuit, and to lithium battery. Copper oxides, mainly including $Cu_2O$ and CuO, are important semiconductors for the wide applications in solar cell, catalysis, lithium-ion battery, and sensor. Due to their low cost, low toxicity, and easy synthesis, copper oxides have received much research interest in recent year. Herein, we review the crystallization of copper oxides by designing various chemical reaction routes, for example, the synthesis of $Cu_2O$ by reduction route, the oxidation of copper to $Cu_2O$ or CuO, the chemical transformation of $Cu_2O$ to CuO, the chemical precipitation of CuO. In the designed reaction system, ligands, pH, inorganic ions, temperature were used to control both chemical reactions and the crystallization processes, which finally determined the phases, morphologies and sizes of copper oxides. Furthermore, copper oxides with different structures as electrode materials for lithium-ion batteries were also reviewed. This review presents a simple route to study the reaction-crystallization-performance relationship of Cu-based materials, which can be extended to other inorganic oxides.

• 공업화학
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• 제30권3호
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• pp.345-351
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• 2019

본 연구에서는 $TiO_2$를 기반으로 한 중공사형 흡착제를 제조와 다양한 금속산화물 첨가에 따른 비소 흡착 특성을 평가하였다. 실험 결과 $TiO_2$ 중공사형 흡착제가 가장 우수한 비소 흡착 성능을 보였으며, 금속산화물을 첨가한 경우 금속산화물이 $TiO_2$ 표면의 산점을 막음으로 인해 오히려 비소 흡착 성능이 저하되었다. 그러나 장시간 비소 흡착 성능을 비교한 결과 $Al_2O_3$를 첨가한 중공사형 흡착제의 비소 흡착 성능이 증진되었다. 또한 비표면적 및 기공 크기가 상대적으로 클수록 비소 흡착 성능이 우수하였으며, 루이스 산점과 브뢴스테드 산점이 풍부하게 존재할수록 흡착에 유리한 사이트가 제공됨을 확인하였다. 이를 통해 기존 파우더 형태의 상용 $TiO_2$를 담체 형태로도 제조하여 소규모 정수처리 시설에 적용이 가능할 것으로 판단된다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.87-88
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• 2012

Metal oxide nanostructures have been applied to various fields such as energy, catalysts and electronics. We have freely designed one and two-dimensional (1 and 2-D) metal (transition metals and lanthanides) oxide nanostructures, characterized them using various techniques including scanning electron microscopy, transmission electron microscopy, X-ray diffraction crystallography, thermogravimetric analysis, FT-IR, UV-visible-NIR absorption, Raman, photoluminescence, X-ray photoelectron spectroscopy, and temperature-programmed thermal desorption (reaction) mass spectrometry. In addition, Ag- and Au-doped metal oxides will be discussed in this talk.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.404-408
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• 2001

This paper focuses on the pilot-scale investigation of direct recycling of electric arc furnace (EAF) stainless steelmaking dust. The direct recycling of EAF dust is to make pellets with the mixture of the dust and the reducing agent carbon, then introduce the pellets to the EAF. The valuable metals in the dust are reduced and get into the steel as the alloying elements. Experiments simulating direct recycling in an EAF were performed using an induction furnace. But it seems difficult to reduce all metal oxides in the dust so that some metal reducing agents added in the late stage of reduction process. The valuable metals in the dust were reduced partly by carbon and partly by metal reducing agent for the economical concern. The recovery of iron, chromium and nickel from the flue dust and the amount of metal oxides in the slag were measured. The results showed that the direct recycling of EAF stainless steelmaking dust is practicable. It wes also found that direct recycling of flue EAF stainless steelmaking dusts does not affect the chemistry and quality of stainless steel produced in the EAF. It is benefit not only for the environmental protection but also for the recovery of valuable metal resources in this way.

• 공업화학
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• 제16권4호
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• pp.542-548
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• 2005

몇 가지 금속 산화물에 플루오르르 치환된 카르복시산의 자기조립박막을 제조하였다. 사슬 길이의 영향을 비교하기 위하여 퍼플루오르도테칸 산과 퍼플루오르옥타데칸 산을 사용하였다. 사용된 금속 산화물은 알루미나, 탄탈리아, 티타니아, 지르코니아였다. 자기조립박막의 형성은 DRIFT (Diffuse Reflectance Infrared Fourier Transform) 분광법으로 확인하였다. 퍼플루오르탄화수소는 소수성을 가지므로 형성된 자기조립박막도 소수성을 지닐 것으로 예측된다. 형성된 자기조립박막의 DRIFT 스펙트럼의 품질은 금속산화물의 성분 원소뿐만 아니라 분말으 크기에 따라서도 달라졌다.