• Title/Summary/Keyword: chemical and thermal treatment

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Analyses of Thermodynamic Vaporization Behaviour and Voloxidaion Conditions for Metal Oxides (금속산화물의 열역학적 휘발 거동 및 휘발 산화 공정의 조건 분석)

  • Lee, Young Woo;Park, So Young;Park, Byung Heung
    • Journal of Institute of Convergence Technology
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    • v.3 no.2
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    • pp.7-10
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    • 2013
  • Metal oxides are known as stable materials during a thermal treatment. However, some oxides are readily evaporated at high temperatures. A voloxidation process is a head-end process for a pyroprocessing dealing with spent nuclear fuels (SF). In SFs, fission productions are in the form of oxides and some of them would be evaporated during the voloxidation process. Therefore, it is of importance to analyse the vapor pressures of metal oxides so that the material flows throughout the pyroprocessing could be estimated. In this work, vapor pressures of relevant metal oxides were calculated and presented to draw a baseline on the material flow of the pyroprocessing.

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The Molecular Structures of Poly(3-hexylthiophene) Films Determine the Contact Properties at the Electrode/Semiconductor Interface

  • Park, Yeong Don
    • Bulletin of the Korean Chemical Society
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    • v.35 no.8
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    • pp.2277-2280
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    • 2014
  • The contact properties between gold and poly(3-hexylthiophene) (P3HT) films having either of two distinct molecular orientations and orderings were investigated. Thermal treatment increased the molecular ordering of P3HT and remarkably reduced the contact resistance at the electrode/semiconductor interface, which enhanced the electrical performance. This phenomenon was understood in terms of a small degree of metal penetration into the P3HT film as a result of the thermal treatment, which formed a sharp interface at the contact interface between the gold electrode and the organic semiconductor.

Hydrothermal Synthesis of Mesostructured Vanadium Oxide and Application of UV-Ozone Treatment

  • Chang, Ju-Yeon;Jung, Duk-Young
    • Bulletin of the Korean Chemical Society
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    • v.24 no.5
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    • pp.613-616
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    • 2003
  • Effect on hydrothermal treatment of lamellar vanadium oxides was investigated and the formation of hexagonal and cubic mesophase was found. This lamellar materials were prepared by mixing of cetyltrimethylammonium-bromide and pH-controlled sodium metavanadate solution. Thermal method and UV/O₃treatment were applied to extract organic template. The structure of resulting product was studied by powder X-ray diffraction and transmission electron microscopy (TEM).

The Coating Performance of UV Curable Urethane Acrylate Coatings for Fancy Veneer Overlayed Plywood Flooring

  • Lee, Byoung-Hoo;Kim, Hyun-Joong;Lee, Young-Kyu
    • Journal of the Korean Wood Science and Technology
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    • v.32 no.6
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    • pp.23-35
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    • 2004
  • The goal of study was to investigate the influence of the acrylated urethane oligomer on mechanical properties, the chemical resistance and thermal resistance of the UV curable urethane acrylate coatings for fancy veneer overlayed plywood flooring. The pencil hardness and abrasion resistance of the coated fancy veneer overlayed plywood floorings increased with increasing the acrylate functionality of the acrylated urethane oligomer. In the case of the UV cured film containing hexa-functional acrylated aliphatic urethane oligomer, high discoloration of the coated fancy veneer overlayed plywood flooring was observed near the cracks at the beginning of the chemical treatment. In this study, it was found that the degradation of the UV cured film caused by an alkaline reagent was higher than that of the UV cured film caused by an acidic treatment.

Analyses on the Increment of Surface Hydrophobicity of Epoxy Composites by Thermal Treatment (열철리에 따른 Epoxy 복합재료의 표면 소수성증가에 관한 해석)

  • Lim, Kyung-Bum;Lee, Beak-Su;Chung, Mu-Yong;Lee, Duck-Chool
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.50 no.4
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    • pp.153-160
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    • 2001
  • In order to analyze the degradation process of epoxy/glass fiber for outdoor condition, FRP laminate was exposed to high temperature. Then, the degradation process was evaluated by comparing contact angle, surface potential, surface resistivity, and XPS. The experimental results showed that the amount of weight loss, contact angle, surface potential and surface resistivity increased up to 200 $^{\circ}C$ as a function of temperature. These phenomena show the existence of hydrophobic surface. With the change to the hydrophobic surface and the electrical potential and resistivity on FRP surface increased. In XPS to analyze surface chemical structures, the increased hydrophobicity in thermal increase of unsaturated double bond in carbon chains. Aslo, thermal treatment caused the discoloration on the point of treated surface. These phenomena were attributed to the generations of ether group.

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Effect of Stabilization Processing Conditions on the Thermal Shrinkage and the Thermal Stability of Rayon Fabrics Untreated and Surface-Treated with Phosphoric Acid (인산처리 유·무에 따른 레이온직물의 열수축과 열안정성에 미치는 안정화 공정 조건의 영향)

  • Cho, Donghwan;Lee, Jongmoon;Park, Jong Kyoo
    • Journal of Adhesion and Interface
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    • v.5 no.3
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    • pp.10-17
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    • 2004
  • We investigated the effect of stabilization processing parameters on the thermal shrinkage, thermal stability and microstructure of rayon fabrics stabilized under various conditions such as heating rate, stabilization temperature, atmosphere gas, and chemical treatment. The presence and absence of phosphoric acid treatment and the heating rate have most importantly influenced the thermal shrinkage and the weight change of rayon fabrics. Especially, the phosphoric acid treatment decreases the reduction of thickness, length, and weight of the fabrics by about 80%, 20%, and 26%, respectively, in comparison with the untreated counterparts, showing the protective effectiveness of the thermal shrinkage involved. The thermal stability of stabilized rayon fabrics is also affected by all the processing conditions used: stabilization temperature, phosphoric acid treatment, atmosphere gas, and heating rate. In addition, the surface and diameter of the stabilized fiber significantly depend on the treatment of phosphoric acid prior to stabilization process.

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Synthesis of Silicon Carbide Nano-Powder from a Silicon-Organic Precursor by RF Inductive Thermal Plasma (RF 유도 열플라즈마를 이용한 유기 용매로 부터의 탄화규소 나노 분말 합성)

  • Ko, Sang-Min;Koo, Sang-Man;Kim, Jin-Ho;Cho, Woo-Seok;Hwang, Kwang-Taek
    • Journal of the Korean Ceramic Society
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    • v.49 no.6
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    • pp.523-527
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    • 2012
  • Silicon carbide (SiC) has recently drawn an enormous amount of industrial interest due to its useful mechanical properties, such as its thermal resistance, abrasion resistance and thermal conductivity at high temperatures. In this study, RF thermal plasma (PL-35 Induction Plasma, Tekna CO., Canada) was utilized for the synthesis of high-purity SiC powder from an organic precursor (hexamethyldisilazane, vinyltrimethoxysilane). It was found that the SiC powders obtained by the RF thermal plasma treatment included free carbon and amorphous silica ($SiO_2$). The SiC powders were further purified by a thermal treatment and a HF treatment, resulting in high-purity SiC nano-powder. The particle diameter of the synthesized SiC powder was less than 30 nm. Detailed properties of the microstructure, phase composition, and free carbon content were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), a thermogravimetric (TG) analysis, according to the and Brunauer-Emmett-Teller (BET) specific surface area from N2 isotherms at 77 K.

An Experimental Study of Power Saving Technique in Non-thermal Plasma DeSOx/DeNOx Process (저온 플라즈마 탈황물질 공정의 운전전력 절감을 위한 실험연구)

  • 송영훈;최연석;김한석;신완호;길상인;정상현;최갑석;최현구;김석준
    • Journal of Korean Society for Atmospheric Environment
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    • v.12 no.4
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    • pp.487-494
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    • 1996
  • Simultaneous effects of $C_2H_4$ injection and heterogeneous chemical reactions on non-thermal plasma process to remove $SO_2$ and NOx from flue gas were investigated in the present experimental study. The present results showed that 40% of the electrical power can be reduced in $C_2H_4$ injection and heterogeneous chemical reaction are simultaneously included in the non-thermal plasma precess. As an effort to apply the non-thermal plasma technique to practical flue gas treatment system, a wire-plate type reactor which has technically similar geometry of industrial electrostatic precipitators is used instead of other types of reactors, such as wire-cylinder, packed-bed and surface discharge which are inappropriate to industrial application. In the present study, the photo pictures of positive streamer corona taken by ICCD camera, voltage and current oscillograms, and design criteria of a wire-plate type reactor are also shown, which are needed for industrial application of the non-thermal plasma process.

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Gasification from Surface during Discharge and Thermal Processes in Plasma Display Panel (PDP)

  • Soh, Hyun;Lee, Sang-Moo;Kim, Young-Chai
    • 한국정보디스플레이학회:학술대회논문집
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    • 2004.08a
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    • pp.495-498
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    • 2004
  • PDP use the mixture of inert gases to generate a discharge inside display pixels. Inside of PDP, there exist highly reactive conditions in the gap between two glass panels. MgO layer and phosphor have been investigated as a function of discharge and thermal process. Impurities such as CO, $CO_2$, OH and $H_2O$ in discharge region may deteriorate the characteristics of PDP operation during life time. Change of impurity generation of various MgO and phosphor surfaces were measured by using x-ray photoelectron spectroscopy(XPS) and quadropole mass spectrometer (QMS). Carbon containing species such as C, CO and $CO_2$ were drastically increased on the surfaces during discharge and thermal treatment. Carbon impurities on the MgO and phosphor are the dominant factor for their instability.

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An overview of functionalised carbon nanomaterial for organic pollutant removal

  • Jun, Lau Yien;Mubarak, N.M.;Yee, Min Juey;Yon, Lau Sie;Bing, Chua Han;Khalid, Mohammad;Abdullah, E.C.
    • Journal of Industrial and Engineering Chemistry
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    • v.67
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    • pp.175-186
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    • 2018
  • Carbon nanomaterials (CNMs), particularly carbon nanotube and graphene-based materials, are rapidly emerging as one of the most effective adsorbents for wastewater treatment. CNMs hold great potential as new generation adsorbents due to their high surface to volume ratio, as well as extraordinary chemical, mechanical and thermal stabilities. However, implementation of pristine CNMs in real world applications are still hindered due to their poor solubility in most solvents. Hence, surface modification of CNMs is essential for wastewater treatment application in order to improve its solubility, chemical stability, fouling resistance and efficiency. Numerous studies have reported the applications of functionalized CNMs as very promising adsorbents for treating organic and inorganic wastewater pollutants. In this paper, the removal of organic dye and phenol contaminants from wastewater using various type of functionalized CNMs are highlighted and summarized. Challenges and future opportunities for application of these CNMs as adsorbents in sustainable wastewater treatment are also addressed in this paper.