• Title/Summary/Keyword: material synthesis

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The Synthesis Mechanism of BaTiO3 Nano Particle at Low Temperature by Hydrate Salt Method (Hydrate Salt법을 이용한 Nano BaTiO3 저온합성 메커니즘)

  • Lee, Chang-Hyun;Shin, Hyo-Soon;Yeo, Dong-Hun;Ha, Gook-Hyun;Nahm, Sahn
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.12
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    • pp.852-856
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    • 2014
  • $BaTiO_3$ nano powder can be synthesized by hydrate salt method at $120^{\circ}C$ in air. Decreasing the thickness of thick film, the nano dielectric particle is needed in electronic ceramics. However, the synthesis of $BaTiO_3$ nano particle at low temperature in air and their mechanism were not reported enough. And ultrasonic treatment can be tried because of low temperature process in air. Therefore, in this study, the $BaTiO_3$ nano powder was synthesised with the synthesis time and ultrasonic treatment at $120^{\circ}C$ in air. In the synthesis process, the effects of process were evaluated. From the experimental observation, the synthesis mechanism was proposed. The homogeneous $BaTiO_3$ particle was synthesised by KOH salt solution at $120^{\circ}C$ for 1hour. It was conformed that the ultrasonic treatment effected on the increase of synthesis rate. After cutting the salt powder using FIB, $BaTiO_3$ nano particles observed homogeneously in the cross-section of the salt particle.

Operation Characteristics of Gasification/Melting Pilot Plants for Synthesis Gas Production using Coal and Waste (석탄 및 폐기물로부터 합성가스 제조를 위한 가스화용융 Pilot Plant 운전특성)

  • Chung, Seok-Woo;Yun, Yong-Seung;Yoo, Young-Don
    • 한국신재생에너지학회:학술대회논문집
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    • 2005.06a
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    • pp.561-564
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    • 2005
  • Gasification has been regarded as a very important technology to decrease environmental pollution and to obtain higher efficiency. The gasification process converts carbon containing feedstock into a synthesis gas, composed primarily of CO and $H_2$. And the synthesis gas can be used as a source for power generation or chemical material production. Through more than nine years, IAE developed and upgraded several gasification/melting pilot plant system, and obtained a good quality synthesis gas. This paper illustrates the gasification characteristics and operation results of two 3 ton/day synthesis gas production facilities. One is entrained-bed slagging type coal gasifier system which is normally operated in the temperature range of $1,400\~1,450^{\circ}C,\;8\~10$ bar pressure. And the other is fixed-bed type gasification/melting furnace system using MSW and industrial wastes as a feedstock.

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Electrochemical Performance of Li4Ti5O12 Particles Manufactured Using High Pressure Synthesis Process for Lithium Ion Battery (초고압 합성법으로 제조한 리튬이온전지 음극활물질 Li4Ti5O12의 전기화학적 특성)

  • Ji, Sung Hwa;Jo, Wan Taek;Kim, Hyun Hyo;Kim, Hyojin
    • Korean Journal of Materials Research
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    • v.28 no.6
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    • pp.337-342
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    • 2018
  • Using a high pressure homonizer, we report on the electrochemical performance of $Li_4Ti_5O_{12}(LTO)$ particles manufactured as anode active material for lithium ion battery. High-pressure synthesis processing is performed under conditions in which the mole fraction of Li/Ti is 0.9, the synthesis pressure is 2,000 bar and the numbers of passings-through are 5, 7 and 10. The observed X-ray diffraction patterns show that pure LTO is manufactured when the number of passings-through is 10. It is found from scanning electron microscopy analysis that the average size of synthesized particles decreases as the number of passings-through increases. $LiCoO_2-based$ active cathode materials are used to fabricate several coin half/full cells and their battery characteristics such as lifetime, rate capability and charge transfer resistance are then estimated, revealing quite good electrochemical performance of the LTO particles as an effective anode active material for lithium secondary batteries.

Synthesis of $BaTiO_3$ nanoparticle by a solvothermal method (Solvothermal 방법에 의한 $BaTiO_3$ 나노입자의 합성)

  • Yeo, Ki-Ho;Moon, Byung-Kee;Son, Se-Mo;Chung, Su-Tae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2003.07b
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    • pp.732-734
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    • 2003
  • A solvothermal synthetic method to $BaTiO_3$ nanoparticle has been investigated in toluene solution with $BaTi(OR)_6$ as precursor. A precursor prepared from barium metal with toluene, isopropanol and titanium isopropoxide was used as a starting material. Weight ratio of precursor to solvent prepared in the mixture are 5/100, 10/100, 20/100 and 50/100wt%. At the weight ratio of 50/100wt%, $BaTiO_3$ butterfly twin crystalline(${\fallingdotseq}100nm$) was obtained after synthesis at $250^{\circ}C$ for 20hrs in an autoclave. X-ray diffraction and transmission electron microscopy showed that the product of 50/100wt% has crystallization. At 5/100, 10/100, and 20/100wt%, however, red colloidal solution was obtained after synthesis and crystalline phase of $BaTiO_3$ was not produced.

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Synthesis of TiB2 Dispersed Cu Matrix Composite Material by the Combination of the Mechanical Milling and Plasma Activated Sintering Process (기계적 밀링과 플라즈마 활성 소결법에 의한 TiB2 분산 Cu기 복합재료 제조)

  • Kim, Kyong-Ju;Lee, Gil-Geun;Park, Ik-Min
    • Journal of Powder Materials
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    • v.14 no.5
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    • pp.292-297
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    • 2007
  • The present study was focused on the synthesis of a $TiB_2$ dispersed copper matrix composite material by the combination of the mechanical milling and plasma activated sintering processes. The $Cu/TiB_2$ mixed powder was prepared by the combination of the mechanical milling and reduction processes using the copper oxide and titanium diboride powder as the raw material. The synthesized $Cu/TiB_2$ mixed powder was sintered by the plasma activated sintering process. The hardness and electric conductivity of the sintered bodies were measured using micro vickers hardness and four probe method, respectively. The relative density of $Cu/TiB_2$ composite material sintered at $800^{\circ}C$ showed about 98% of theoretical density. The $Cu-1vol%TiB_2$ composite material has a hardness of about 130Hv and an electric conductivity of about 85% IACS. The hardness and electric conductivity of $Cu-3vol%TiB_2$ composite material were about 140 Hv and about 45% IACS, respectively.

Synthesis of Xanthone Derivatives (키산톤 유도체의 합성)

  • Ko, Ok-Hyun
    • YAKHAK HOEJI
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    • v.41 no.3
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    • pp.294-297
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    • 1997
  • The efficient synthesis of xanthone derivatives, which are important intermediates in the synthesis of psorospermin as a anticancer agent, from 3-(benzyloxy)-2-hydroxybenzoic ac id and 6-allyl-3,5-dihydroxyl-1-tosyloxybenzene as a starting material will be reported herein.

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Synthesis and characteristics of 2,3-dicyanopyrazine derivatives. (신규 2,3-dicyanopyrazine유도체의 합성과 특성)

  • Lee, Bum-Hoon;Jaung, Jae-Yun
    • Proceedings of the Korean Fiber Society Conference
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    • 2001.10a
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    • pp.247-250
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    • 2001
  • 2, 3-Dicyanopyrazine derivatives have been synthesized by condensation of diaminomaleonitrile(DAMN) and a -diketone compounds. Diaminomaleohitrile (DAMN) is well known as a tetramer of hydrogen cyanide and a useful compound in the chemical industry not on]y as a starting material for synthesis of various heterocyclic compounds but also as an intermediate for synthesis of glycine, adenine, guanine et al. (omitted)

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Graphene Synthesis by Low Temperature Chemical Vapor Deposition and Rapid Thermal Anneal (저온 화학기상증착법 및 급속가열 공정을 이용한 그래핀의 합성)

  • Lim, Sung-Kyu;Mun, Jeong-Hun;Lee, Hi-Deok;Yoo, Jung-Ho;Yang, Jun-Mo;Wang, Jin-Suk
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.12
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    • pp.1095-1099
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    • 2009
  • As a substitute material for silicon, we synthesized few layer graphene (FLG) by CVD process with a 300-nm-thick nickel film deposited on the silicon substrate and found out the lowest temperature for graphene synthesis. Raman spectroscopy study showed that the D peak (wave length : ${\sim}1,350\;cm^{-1}$) of graphene was minimized and then the 2D one (wave length : ${sim}2,700\;cm^{-1}$) appeared when rapid thermal anneal is carried out with the $C_2H_2$ treated nickel film. This study demonstrates that a high quality FLG formed at a low temperature of $400^{\circ}C$ is applicable as CMOS devices and transparent electrode materials.