• Title/Summary/Keyword: 재매몰

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Effect of Cristobalite and Quartz on the Compression Strength and Thermal Expansion Coefficients of Gold Alloy Investment Materials (금합금계 매몰재의 Cristobalite와 Quartz 첨가량에 따른 열팽창과 압축강도 변화)

  • Man-So Han
    • The Journal of Engineering Research
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    • v.6 no.2
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    • pp.141-151
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    • 2004

  • The physical properties of gold investment materials are depending on it's thermal expansion coefficients, compressive strength, and particles size distributions. Normally the gold investment materials are consisted of cristobalite, quartz and plaster. Since the thermal expansion coefficient of cristobalite and quartz are $2.6\times10^{-6}/^\circC$, $2.32\times10^{-6}/^\circC$, respectively, the composition ratio of each components influence the thermal and clinical properties of gold investment materials. Recently are imported from overseas and the commercial market is expected to expand. Thus it is necessary to develop the optimum strength and compressive strength of gold investment materials which the an homogeneous size distribution and thermal expansion coefficients. Therefore two different experiments has been done. Firstly the homogeneous cristobalite and quartz are made by pulverizing milling. Secondly the compressive strength and thermal expansion coefficients are analysed by the composition ratio of cristobalite and quartz. As a results of experiments, homogeneous distribution of cristobalite and quartz are observed by pulverizing and milling. The optimum compressive strength was obtained at the ratio of 45:25 cristobalite, quartz respectively.

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전문가심층분석 - FMD 매몰농장 재입식 절차와 청소 및 소독 요령

  • 축산물등급판정소
    • KAPE Magazine
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    • s.176
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    • pp.6-7
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    • 2011

  • 가축 재입식이 시 군의 점검결과에 따라 30일 이후에 입식이 가능해지면서 농가의 손이 바빠질 것으로 보인다. 이번에 수정된 재입식 절차는 가축방역관의 지적상항을 보완하고 문제점이 해결되어야만 재입식이 가능하다. 본고에서는 FMD 매몰 농장 재입식 절차와 청소 소독 요령에 대해 언급하도록 한다.

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Study on Phosphate Investment for High Temperature Precision Castings(II);The Effect of MgO on the characteristics of the Investment (고온정밀주조용 인산염계 매몰재에 관한연구(II);매몰재의 특성에 미치는 Mgo의 영향)

  • SunWoo, Jung-Ho;Lee, Jong-Nam
    • Journal of Korea Foundry Society
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    • v.5 no.2
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    • pp.97-108
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    • 1985

  • In order to investigate the effect of magnesia clinker on the characteristics of the investments, temperature change during setting, setting time, compressive strength and thermal expansion of the investments were measured, and x-ray analyses were also performed. The investments were prepared in accordance with variation of the content and the particle size of magnesia clinker respectively. From this experiment, the results were summarized as follows; 1. Temperature of the investments during setting rapidly increased with increase of MgO contents and decrease of the particle size of magnesia clinker. 2. Setting time decreased with increase of MgO contents and decrease of the particle size of magnesia clinker. 3. Compressive strength increased with increase of MgO contents and decrease of the particle size of magnesia clinker. 4. Thermal expansion decreased with increase of MgO contents and decrease of the particle size of magnesia clinker. From the above results, the investment which contains 8% of MgO (270-325mesh) could be recommended for phosphate investment castings.

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