• Title/Summary/Keyword: MA powder

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Sintering Characteristics of Nickel Silicide Alloy (니켈 실리사이드 화합물의 소결특성)

  • Byun, Chang-Sop;Lee, Sang-Hou
    • Korean Journal of Materials Research
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    • v.16 no.6
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    • pp.341-345
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    • 2006
  • [ $Ni_2Si$ ] mixed powders were mechanically alloyed by a ball mill and then processed by hot isostatic pressing (HIP) and spark plasma sintering (SPS). In the powder that was mechanically alloyed for 15minutes(MA 15 min), only Ni and Si were observed but in the powder that was mechanically alloyed for 30minutes(MA 30 min), $Ni_2Si$, Ni and Si were mixed together. Some of the MA 15 min powder and MA 30 min powder were processed by HIP under pressure of 150MPa at the temperature of $1000^{\circ}C$ for two hours and some of them were processed by SPS under pressure of 60 MPa at the temperature of $1000^{\circ}C$ for 60 seconds. Both methods completely compounded the powders to $Ni_2Si$. The maximum density of sintered lumps by HIP method was 99.5% and the maximum density of the sintered lump by SPS method was 99.3%. with the hardness of HRc 66 with the hardness of HRc 63. Therefore, the SPS method that can sinter in short time at low cost is considered to be more economical that the HIP method that requires complicated sintering conditions and high cost and the sintering can produce target materials in desired sizes and shapes to be used for thin film.

Development of MA Packaging Materials for Freshness Extension of Fruits and Vegetables(2) (과실 채소류의 MA포장용 소재의 효과제고에 관한 연구(2))

  • Park, Hyung-Woo;Park, Jong-Dae;Kim, Byung-Sam;Kim, Hoon;Yang, Han-Chul
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.4 no.1
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    • pp.17-21
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    • 1997
  • Zeolite powder used by molecular sieve, adsorbants and catalist. 1N HCl teated zeolite powders for freshness extension of fruits and vegetables showed that specific surface area was $300.29m^2/g$ largest then that of the others, and ethylene gas adsorbability was 29.07 cc/g. And then 0.5N NaCl Henting after 1N HCl treated zeolite powder showed that specific surface area and ethylene gas adsorbability was $329.43m^2/g$ and 35.64 cc/g largest then those of the others. Specific surface area of processed zeolite powder treated by high intensity magnetic seperator(HIMS) showed $369.67m^2.g$, ethylene gas adsorbability was 39.87cc/g. In this study, it could be employ 0.5N NaCl treat and HIMS methods as MA packaging materials for freshess extension of fruits and vegetables.

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A study on the Effect of Coupling Agents on the Mechanical Properties of WPC (WPC제조시 coupling agent가 기계적 물성에 미치는 영향에 관한 연구)

  • Sin, Gyeong-Seop;Hwang, Taek-Seong
    • Korean Journal of Materials Research
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    • v.8 no.12
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    • pp.1077-1081
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    • 1998
  • Wood powder as reinforcing fillers and polyethylene as a matrix have been used for wood plastic composites (WPC). In preparing WPC, counting agents (such as MA and MAOMS) were also used in order to improve the bonding force between matrix and fillers. In this study, the effect of wood powder, MA, MAOMS concentration on the mechanical properties and interface phenomena on the composites was evaluated The tensile strength of 3wt% MA-treated composites reached its maximum value of 25.91MPa while 3wt% MAOMS-treated composites attained the maximum value of 22.48MPa. The maximum impact strength of MA and MAMOS-treated composites were 44.38J/m and 36.09J/m, respectively, when 3wt% of coupling agent was introduced.

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Synthesis and Microstructural Characterization of Cu-C Composite Metal Powder by Mechanical Alloying (기계적 합금화 방법에 의한 Cu-C계 복합금속분말의 제조 및 미세구조 제어 특성)

  • 이광민
    • Journal of Powder Materials
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    • v.4 no.1
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    • pp.42-47
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    • 1997
  • It was investigated whether mechanical alloying (MA) processing could be more effective to the formation of metallic composite powder in Cu-C system. Elemental powder mixtures of Cu-70vo1.%C were mechanically alloyed with an attritor in an argon atmosphere and microstructural evolution was examined by X-ray diffraction analysis, scanning electron microscopy and transmission electron microscopy. It has been found that even with the high volume fraction of immiscible graphite in Cu-C system, the refinement with a few ten nanometer size as well as the highly uniform distribution of copper phases have been achieved by the MA processing.

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New Co10Fe10Mn35Ni35Zn10 high-entropy alloy Fabricated by Powder Metallurgy (분말야금법으로 제조한 새로운 Co10Fe10Mn35Ni35Zn10 고엔트로피 합금)

  • Yim, Dami;Park, Hyung Keun;Tapia, Antonio Joao Seco Ferreira;Lee, Byeong-Joo;Kim, Hyoung Seop
    • Journal of Powder Materials
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    • v.25 no.3
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    • pp.208-212
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    • 2018
  • In this paper, a new $Co_{10}Fe_{10}Mn_{35}Ni_{35}Zn_{10}$ high entropy alloy (HEA) is identified as a strong candidate for the single face-centered cubic (FCC) structure screened using the upgraded TCFE2000 thermodynamic CALPHAD database. The $Co_{10}Fe_{10}Mn_{35}Ni_{35}Zn_{10}$ HEA is fabricated using the mechanical (MA) procedure and pressure-less sintering method. The $Co_{10}Fe_{10}Mn_{35}Ni_{35}Zn_{10}$ HEA, which consists of elements with a large difference in melting point and atomic size, is successfully fabricated using powder metallurgy techniques. The MA behavior, microstructure, and mechanical properties of the $Co_{10}Fe_{10}Mn_{35}Ni_{35}Zn_{10}$ HEA are systematically studied to understand the MA behavior and develop advanced techniques for fabricating HEA products. After MA, a single FCC phase is found. After sintering at $900^{\circ}C$, the microstructure has an FCC single phase with an average grain size of $18{\mu}m$. Finally, the $Co_{10}Fe_{10}Mn_{35}Ni_{35}Zn_{10}$ HEA has a compressive yield strength of 302 MPa.

Effect of Enzyme-Treated Radish Leaves on Lipid Metabolism in Rats Fed a High-Fat Diet

  • Kim, Yu-Na;Ku, Kyung-Hyung;Kang, Sin-Kwon;Choi, Jeong-Hwa
    • Preventive Nutrition and Food Science
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    • v.16 no.1
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    • pp.1-7
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    • 2011
  • The purpose of this study was to investigate the effect of enzyme-treated radish (Raphanus sativus L.) leaves on lipid metabolism in rats fed a high fat diet. Rats were divided into four experimental groups which were composed of a high fat diet group (HF group), a high fat diet with 10% radish leaf powder-supplemented group (MA group), a high fat diet with 5% enzyme-treated radish leaf powder-supplemented group (MB group) and a high fat diet with 10% enzyme-treated radish leaf powder-supplemented group (MC group). Total dietary fiber content of enzyme-treated radish leaves were greater than untreated radish leaves. Body weight gain and food efficiency ratio (FER) of the HF group increased compared to the MA, MB and MC groups. The serum total cholesterol, LDL-cholesterol and atherogenic index contents in the radish leaf powder-supplemented groups were lower than that of the HF group, while those values for the MB and MC groups were significantly lower than that of the HF group. The serum HDL-cholesterol contents of the MB and MC groups increased compared to the HF group. The hepatic triglyceride contents of the MA, MB and MC groups decreased compared to the HF group. In fact, the hepatic triglyceride contents of the MB and MC groups were significantly lower than the MA group. The hepatic total cholesterol contents of the MB and MC groups significantly decreased compared to those of the HF group. The fecal total cholesterol contents of the MA, MB and MC groups significantly increased compared to those of the HF group. These results indicate that supplementation with enzyme-treated radish leaves increase the useful fiber contents. Furthermore, it may have a pronounced impact on lipid metabolism of serum and liver in rats fed a high fat diet.