• 콘크리트학회논문집
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• 제19권5호
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• pp.539-547
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• 2007

본 연구에서는 폴리머 개질 페이스트의 응결 시간, 건조수축, 강도, 동결융해저항성 및 흡수율에 미치는 결합재량 및 알루미나 분말 혼입량의 영향에 대하여 검토하였다. 그 결과, SBR 및 PAE폴리머 개질 페이스트의 응결 시간은 결합재량이 증가함에 따라 지연되는 경향을 보였다. 폴리머 종류에 관계없이 SBR PAE 폴리머 개질 페이스트의 건조수축은 결합재량 및 알루미나 분말 혼입량이 증가함에 따라 감소하는 경향을 나타내었다. 폴리머 종류에 관계없이 SBR 및 PAE 폴리머 개질 페이스트의 인장 및 부착강도는 결합재량 및 알루미나 분말 혼입량이 증가함에 따라 증가하는 경향을 나타냈다. SBR 및 PAE 폴리머 개질 페이스트의 내구성 지수는 폴리머 종류에 관계없이, 알루미나 분말 혼입량의 증가에 따라 증가하는 경향을 보였다. 폴리머 종류에 관계없이 SBR 및 PAE 폴리머 개질 페이스트의 흡수율은 결합재량 및 알루미나 분말 혼입량이 증가함에 따라 감소하는 경향을 나타내었다.

• 한국건설순환자원학회논문집
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• 제9권1호
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• pp.26-32
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• 2021

분말형 견운모는 폐기물 재활용 차원에서 화학, 광물 분야에서 활발하게 연구가 이루어지고 있고, 비교적 저렴하게 구할 수 있는 재료이며, 일반 운모와 마찬가지로 낮은 열전도율을 가지고 있다. 따라서 본 연구에서는 분말형 견운모를 활용하여 모르타르의 열전도율을 개선하고, 이를 통해 시멘트 복합체용 내화재료로서와 활용가능성을 확인하고자 하였다. 분말형 견운모를 혼입한 시멘트 모르타르를 제작하고, 이의 열전도율 및 고온 노출 전후의 압축강도를 비교 평가하여 내화성능을 규명하고자 하였다. 실험 결과에 따르면, 분말형 견운모를 혼입하는 경우 압축강도가 감소하는 것으로 나타났으며, 혼입량 증가에 따른 압축강도의 감소는 미미하였다. 분말형 견운모를 혼입하면, 열전도율이 감소하며, 600℃, 900℃, 1,200℃에 소성된 모르타르 시험체의 잔존강도가 플레인 모르타르에 비해 높게 나타났다. 실험 결과를 종합적으로 평가해 볼 때, 분말형 견운모는 시멘트 복합체용 내화 재료로서의 활용가능성이 존재한다고 결론지을 수 있다.

• 한국분말재료학회지
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• 제8권3호
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• pp.210-213
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• 2001

$Si_3N_4$/TiN nano/nano-type composites were successfully fabricated by the combination of a mechano-chemical grinding (MCG) method and a short time sintering process, and their wear resistance was evaluated. Powder mixtures of $\alpha-Si_3N_4$and Ti were prepared using mechano-chemical grinding process and the resulting nanocomposite powder mixtures were consolidated using pulsed electric current sintering (PECS). TEM observation showed that the nano/nano-type composites consisted of homogeneous and very fine matrix grains with the size less than 100 nm. The obtained $Si_3N_4$-based nano/nano-type showed high wear resistance and electric discharge machinability.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 1999년도 춘계학술대회 및 발표대회 강연 및 발표논문 초록집
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• pp.23-23
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• 1999

• 한국정보기술응용학회:학술대회논문집
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• 한국정보기술응용학회 2001년도 추계공동학술대회 논문자료집 정보화 젼략 패러다임의 변화에 대한 보기술의 대응
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• pp.149-150
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• 2001

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 1999년도 추계학술강연 및 발표대회 강연 및 발표논문 초록집
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• pp.32-32
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• 1999

• 펄프종이기술
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• 제38권5호
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• pp.24-30
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• 2006

This study was performed to characterize inverse emulsion type cationic polyacrylamide (PAM) and to compare with powder and salt dispersion type PAMs as a retention and drainage aid. Salt dispersion type PAM has defects of high amount of salt which increases conductivity of white water, low active polymer contents and relatively worse retention and drainage properties than others because of its low molecular weight. Powder type PAM has benefit of high active polymer contents and good retention and drainage properties, but defects of low dissolution speed and insoluble particle generation were observed. However, inverse emulsion type showed the best retention and drainage aids among them by controlling molecular weight and morphology easily and it had relatively higher active polymer contents and better solubility.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(II)
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• pp.497-500
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• 2005

This study was performed to evaluate the characteristics which are slump, air content and time of set in fresh concrete and compressive strength of hardened concrete containing slag powder and fly-ash. Replacement rate of FA is fixed on 10$\%$ and replacement rate of slag powder are 0$\%$, 20$\%$ and 30$\%$. Also AE water-reducing agents(standard type, accelerating type) are used. The results were as follows. (1)Slump flow of concrete using AE water-reducing agents is similar. Flowability is incresed when replacement rate of slag powder is increased due to slag powder's ball bearing reaction.(2)Time of set of concrete using accelerating type agent is more faster than that of concrete using standard type agent because of ettringite generation that promote setting.(3)Early strength of three-component concrete using accelerating type agent is higher than that using standard type agent. Therefore cumulative pore is reduced due to ettringite

• 전기학회논문지
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• 제56권12호
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• pp.2196-2201
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• 2007

Materials used at microwave are usually used as a dielectric with a manufacturing purpose of printed circuit boards, etc. Complex permittivity of them can be measured from attenuation constant or propagation constant of a transmission line using a microstrip line with bulk type. But as the technique recently which can manufacture to have complex permittivity and permeability demanded using nonferrous metals for powder-type grows up, we need sensors and methods which can measure characteristics of powder-type materials. So far measuring methods of permittivity and permeability with waveguide or coaxial cable are used but they have faults which have a complex measurement method and are difficult to simultaneously measure permittivity and permeability. In this paper, a simultaneous measuring method of permittivity and permeability with 2-port coaxial cable and a new proposed calculation. The proposed 2-port coaxial cable is designed to be easy to insert materials and to have a wideband. We measure permittivity and permeability of magnetic powder(Ni-Fe-Mo, Ni-Fe) which reveal its characteristic at $0.3{\sim}1.3GHz$ to identify the proposed sensor.

• Journal of Welding and Joining
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• 제20권1호
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• pp.47-54
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• 2002

Powder type Ag system insert metals were manufactured by ball milling process. The variables of milling process such as milling media, revolution speed and powder/ball weight ratio were constant except the milling time. The milling times were selected for 24, 48 and 72 hours. The insert metals made by milling process were evaluated by performing scanning electron microscope, x-ray and DSC(differential scanning calorimetry) analysis, and further in terms of wettability test. The selected insert metals that have the good characteristics compared to commercial insert metals were applied to make the brazed joints of the steel/steel and the steel/WC superhard particles. The characterizations of those brazed joints were also conducted by microstructural observations, shear tensile tests and microhardness measurements. The results indicated that milling time of 48 hours for making powder type insert metals was the best condition showing the small amount of oxides residue, low wetting angle and stable microstructure. The brazed joints that applied the 48 hours milled insert metal were very sound condition indicating the shear tensile value of $2.29{\times}102$ MPa and the microhardness of 138VHN. Further, the amount of the porosity was appeared to be lower than that of the commercial insert metals.