• Title/Summary/Keyword: Reduction technology

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Synthesis of Ultrafine Titanium Carbide Powder by Novel Thermo-Reduction Process (신 열환원 공정에 의한 초미립 티타늄 카바이드 분말 합성)

  • ;S.V. Alexandrovskii
    • Journal of Powder Materials
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    • v.10 no.6
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    • pp.390-394
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    • 2003
  • Ultra fine titanium carbide particles were synthesized by novel metallic thermo-reduction process. The vaporized TiC1$_4$+$CCl_4$ gases were reacted with liquid magnesium and the fine titanium carbide particles were then produced by combining the released titanium and carbon atoms. The vacuum treatment was followed to remove the residual phases of MgC1$_2$ and excess Mg. The stoichiometry, microstructure, fixed and carbon contents and lattice parameter were investigated in titanium carbide powders produced in various reaction parameters.

Speckle Reduction in the Wavelet Domain for Image with Optical Coherence Tomography

  • Chang, Ju-Wan;Lee, Chang-Su;Na, Ji-Hoon;Paes, Stephane;Lee, Byeong-Ha
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.2459-2463
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    • 2005
  • Optical coherence tomography (OCT) is high resolution medical imaging system which is obtaining image inside biological objects with non-destructive method. OCT system is based on Michelson interferometer with a reciprocating mirror in the reference arm and a biological object in the sample arm. The obtained OCT image suffers from a granular or mottled image, called speckle. Speckle is caused by random interferences between reflected coherence waves. In this paper, we propose effective speckle reduction method that uses wavelet transform. With wavelet domain image, sub-windowing and thresholding are performed. Finally, speckle reduction experiments for Misgurnus mizolepis skin and rat eye images are shown.

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A study of Carbon Dioxide Emissions due to the Cloud computing security (클라우드 컴퓨팅 보안에 따른 이산화탄소 배출에 관한 연구)

  • Jeon, Jeong Hoon
    • Convergence Security Journal
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    • v.14 no.4
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    • pp.101-108
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    • 2014
  • Recently, The cloud computing technology is emerging as an important issue in the world and the cloud computing has attracted much attention to the technology about carbon dioxide reduction. However, Unlike to the positive aspects of a cloud computing are included several security vulnerabilities. For this reason, the carbon dioxide reduction of a cloud computing technology has a differences. Therefore, this paper will be analyzed to the carbon dioxide emission factors of a cloud computing through the cloud case studies related $CO_2$ emissions and experiments measured of $CO_2$ emissions a security system. and In the future, this is expected to be utilized as a basis for the security design and performance improvement.

Synthesis of Aluminum Nitride Nanopowders by Carbothermal Reduction of Aluminum Oxide and Subsequent In-situ Nitridization (산화알루미늄 분말의 탄소열환원 및 직접 질화반응을 통한 질화알루미늄 나노분말의 합성)

  • Seo, Kyung-Won;Lee, Seong-Yong;Park, Jong-Ku;Kim, Sung-Hyun
    • Journal of Powder Materials
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    • v.13 no.6 s.59
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    • pp.432-438
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    • 2006
  • Aluminum nitride (AlN) nanopowders with low degree of agglomeration and uniform particle size were synthesized by carbothermal reduction of alumina and subsequent direct nitridization. Boehmite powder was homogeneously admixed with carbon black nanopowders by ball milling. The powder mixture was treated under ammonia atmosphere to synthesize AlN powder at lour temperature. The effect of process variables such as boehmite/carbon black powder ratio, reaction temperature and reaction time on the synthesis of AlN nanopowder was investigated.

An Analysis on the Policy of $CO_2$Reduction and Sequestration Technology R&D in Advanced Countries and Korea (국내외 $CO_2$ 저감 및 처리 기술개발 정책동향 분석)

  • 최상진;이덕기;박수억
    • Journal of Korea Technology Innovation Society
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    • v.6 no.4
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    • pp.535-550
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    • 2003
  • Ever since the United Nations Framework Convention on Climate Change(UNFCCC) was agreed to stabilized greenhouse gas(GHG) concentration in the atmosphere at 1992, most countries including Korea have been developing strategic plans and implementing a number of R&D programs to develop the measures to reduce the emission of GHG. Therefore, it is necessary to investigate the plans and programs for our country to develop more competitive technologies and to be more active and attentive in international meetings. In this paper, the energy policies of advanced countries will be analysed and be compared each other along with the Korean policy. Furthermore, the carbon dioxide reduction and sequestration R&D programs in the countries will also be studied.

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Weight Reduction for Compressor Brackets (컴프레서 브래킷의 경량화)

  • Kwon, Soon-Ki
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.1
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    • pp.65-69
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    • 2012
  • According to the developments of automobile industry, a technology has been studied in a point of view of environment, which is to increase fuel consumption rate. Especially it is well known that a weight reduction is one of the main technologies to increase the fuel consumption rate and, also to decrease the cost of manufacturing. This paper presents the method for reducing weight of bracket, which connects air conditioner compressor to engine, based on dynamic stress analysis and engineer's intuition for optimal design.

Fabrication of Nanostructured Fe-Co Alloy Powders by Hydrogen Reduction and its Magnetic Properties

  • Lee, Young-Jung;Lee, Baek-Hee;Kim, Gil-Su;Lee, Kyu-Hwan;Kim, Young-Do
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.120-121
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    • 2006
  • Magnetic properties of nanostructured materials are affected by the microstructures such as grain size (or particle size), internal strain and crystal structure. Thus, it is necessary to study the synthesis of nanostructured materials to make significant improvements in their magnetic properties. In this study, nanostructured Fe-20at.%Co and Fe-50at.%Co alloy powders were prepared by hydrogen reduction from the two oxide powder mixtures, $Fe_2O_3$ and $Co_3O_4$. Furthermore, the effect of microstructure on the magnetic properties of hydrogen reduced Fe-Co alloy powders was examined using XRD, SEM, TEM, and VSM.

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Reduction of Green House Gases by Bioenergy Supplying in Korea (국내 바이오에너지 보급에 따른 온실가스 저감 평가)

  • Hong, Yeon Ki
    • Journal of Institute of Convergence Technology
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    • v.4 no.1
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    • pp.15-20
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    • 2014
  • Recently, the development of renewable energy sources in Korea has been needed due to climate change. One of powerful alternative energy resources to mitigate emission is to switch conventional fuels to renewable energy, such as bioenergy. In this study, current status of bioenergy conversion technology and its supply in Korea was investigate. Based on theoretical, technical and realizable potential of biomass in Korea, the amount of reduction of green house gases was estimated. The results shown that the contribution of biomass on 2020 reduction target of green house gases emission in power generation was $513,000\;tCO_2/yr$ and utilization ratio of technical potential of biomass was 6.4%. For the effective supply of bioenergy in Korea, more exact estimation of realizable potential of biomass in Korea and stable supply sources are needed.

Cleaning Interval Selection for SCR Considering Endurance Reliability and Emissions Reduction Efficiency in Heavy Duty Commercial Engine (대형 상용 엔진에서 SCR의 클리닝 주기 선정 및 저감효율에 따른 내구신뢰성 특성 연구)

  • Shin, Jaesik;Kang, Jungho;Kim, Hyongjun
    • Journal of Applied Reliability
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    • v.18 no.1
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    • pp.66-71
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    • 2018
  • Purpose: Performance recovered from SCR through cleaning was studied, measuring differential pressure, NOx reduction efficiency, fuel consumption and engine power before and after cleaning. Ideal cleaning intervals are proposed based on SCR mileage and differential pressure. SCR endurance and reliability improvements through cleaning were studied through physicochemical testing of SCR durability at 43,000km 50,000km, and 110,000km respectively. Methods: Engine power, fuel consumption and exhaust gas were measured using engine full load tests and ND-13 MODE by installing the SCR before cleaned at total engine mileages of 400,000 km, 300,000km and 200,000km. The same tests were performed after cleaning the SCR catalytic converter. Endurance and reliability of the SCR cleaning was studied through the same test by SCR catalyst after each 43,000km 50,000km, 110,000km, durability test on SCR cleaning. Conclusion: We confirmed the low-performance of the SCR due to clogging is restored by SCR cleaning technology. The NOx reduction efficiency was restored to 82%, 86% and 88% from 69%, 72% and 79%. As well as the NOx reduction efficiency, it was confirmed that the engine power, fuel consumption and back pressure was restored to fresh SCR levels. As a result of the durability and reliability achieved through SCR cleaning, we confined the appearance and reduction efficiency through visual inspection and ND-13 MODE are similar to new SCR catalysts. Finally, it was judged that there was no change in performance even when driving the SCR without cleaning throughout the 100,000 km mileage warranty.

Resazurin Reduction Time Test to Determine Post-pasteurization Contamination and Shelf Life of Market Milk (시유의 2차오염과 저장가능기간을 결정하기 위한 Resazurin 환원시간검사)

  • Choi, S,H.;Choi, J.J.;Lee, S.B.;Yoon, Y.H.
    • Journal of Animal Science and Technology
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    • v.46 no.6
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    • pp.999-1006
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    • 2004
  • The selective media including NPC agar, DHL agar, MacConkey agar, and Cetrimide desoxycholate agar were compared to determine selectivity for the growth of bacteria Cetrimide desoxycholate agar was better than NPC agar, DHL agar, and MacConkey agar for the growth of psychrotrophic grarn-negatve bacteria including Pseudomonas. and for the inhibition of gram positive bacteria The specificity of resazurin reduction time test was investigated to determine post-pasteurization contamination of market milk. Equal volume of Cetrimide desoxycholate broth was added to market milk, which was then incubated at $21^{\circ}C$ for 18 hours. The growth of bacteria in the incubated milk was detected in resazurin reduction time test. The results in resazurin reduction time test and total bacteria number count of market milk after storage at $7^{\circ}C$ were relatively correlated each other. Pseudomonas was isolated most frequently from the market milk stored at $7^{\circ}C$ for 10 days, and Acinetobacter and Aeromonas followed. Acinetobacter, Pseudomonas and Enterobacter were frequently isolated from the mixture of market milk and Cetrimide desoxycholate broth incubated at $21^{\circ}C$ for 18hours in resazurin reduction time test.