• 한국세라믹학회지
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• 제42권5호
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• pp.314-318
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• 2005

The effect of reaction parameters in the characteristic of $Pb(Zr_{0.52}Ti_{0.48})O_3$ (below nominal PZT) powders by SHS was investigated in this study. In the preparation of PZT, the effect of starting material contents, pressure, additive on phase fraction and morphology was investigated respectively. The optimum condition of PZT powders were prepared by SHS is $0.37Pb_3O_4+0.52ZrO_2+0.48TiO_2+0.35KClO_3+0.5C,\;(P_{Ar}= 50 atm)$. The PZT powder synthesized in this condition had an spherical shape and the particle size of 0.8$\mu$m.

• 한국조리학회지
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• 제21권1호
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• pp.129-142
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• 2015

토마토의 식품가공재료로서의 활용도를 높이기 위해 토마토 분말을 첨가한 국수를 제조하고, 품질특성을 측정하였다. 토마토 분말 첨가(밀가루 양 대비 0.5-2%) 국수의 수분함량은 토마토 분말 1.5%, 2% 첨가구가 낮게 측정되었으며, 조단백질 함량과 조지방함량은 토마토 분말 첨가비율이 증가할수록 감소하였고, 탄수화물 함량은 증가하였다. 삶은 후의 국수 중량과 부피는 토마토 분말 첨가비율이 증가할수록 감소하였으며, 국수 삶은 물의 pH는 토마토 분말 첨가비율이 증가할수록 낮아지고, 탁도는 높아졌다. 토마토 분말 첨가비율이 증가할수록 색도의 L값은 낮아지고, a값은 토마토 분말 무첨가구(control)가 토마토 분말 첨가구에 비해 (-)녹색의 경향이 가장 강했고, b값은 토마토 분말 첨가비율이 증가할수록 높아졌다. 기계적 조직감은 모든 항목에서 토마토 분말첨가비율이 증가할수록 유의적으로 높아졌고, DPPH 라디컬 소거능과 총 폴리페놀 함량도 높아졌다. 관능 기호도는 색과 씹힘성, 전반적인 기호도에서 토마토 분말 첨가구가 무첨가구에 비해 유의적으로 높은 기호도를 나타내었으며 그 중에서도 색과 씹힘성에 대한 기호도는 토마토 분말 1.5%, 2% 첨가구가 가장 높은 기호도를 나타내었고, 전반적인 기호도에서는 토마토 분말 1.5% 첨가구가 가장 높은 기호도를 나타내었다.

• 공업화학
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• 제21권5호
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• pp.527-531
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• 2010

Fe계 metal powder를 이용하여 최적화된 전자파차폐 시트를 제조한 후, 제조된 시트에 physical vapor deposition (PVD)법으로 여러 금속들을 증착시켜 최종 전자파차폐용 시트를 제조하였다. 또한 증착된 금속들의 전자파 효율 특성을 분석하기 위하여 polyvinylidene fluoride (PVdF) 나노섬유 막을 시트로 활용하였다. 전기적 특성을 알아보기 위해 4-point probe로 측정하였으며, energy dispersive spectroscopy (EDS)를 이용하여 제조된 sheet에 금속이 증착되었음을 확인하였다. 차폐효율은 전자파차폐효율측정기를 이용하여 측정하였다. 전기저항은 $1000\;{\AA}$일 때 Cu에서 $641.95{\Omega}{\cdot}cm$로 가장 낮은 저항 값을 나타내었다. 전자파 차폐효율은 증착된 금속의 두께의 증가에 따라 증가되었으며, Cu가 $1000\;{\AA}$으로 증착된 sheet가 최고 효율인 32.5 dB을 나타내었다.

• 한국분말재료학회지
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• 제20권3호
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• pp.215-220
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• 2013

In the present work, 6061 Al-$B_4C$ sintered composites containing different $B_4C$ contents were fabricated and their characteristic were investigated as a function of sintering temperature. For this, composite powders and their compacts with $B_4C$ various contents from 0 to 40 wt.% were fabricated using a planetary ball milling equipment and cold isostatic pressing, respectively, and then they were sintered in the temperature ranges of 580 to $660^{\circ}C$. Above sintering temperature of $640^{\circ}C$, real density was decreased due to the occurrence of sweat phenomena. In addition, it was realized that sinterability of 6061Al-$B_4C$ composite material was lowered with increasing $B_4C$ content, resulting in the decrease in its real density and at the same time in the increment of porosity.

• 한국전기전자재료학회논문지
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• 제21권9호
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• pp.835-843
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• 2008

We have fabricated the source-drain electrodes for OTFTs by screen printing method and manufactured Ag pastes as conductive paste. To obtain excellent conductivity and screen-printability of Ag pastes, the dispersion characteristics of Ag pastes prepared from two types of acryl resins with different molecular structures and Ag powder treated with caprylic acid, triethanol amine and dodecane thiol as surfactant respectively were investigated. The Ag pastes containing Ag powder treated with dodecane thiol having thiol as anchor group or AA4123 with carboxyl group(COOH) of hydrophilic group as binder resin exhibited excellent dispersity. But, Ag pastes(CA-41, TA-41, DT-41) prepared from AA4123 fabricated the insulating layer since the strong interaction between surface of Ag powder and carboxyl group(COOH) of AA4123 interfered with the formation of conduction path among Ag powders. The viscosity behavior of Ag pastes exhibited shear-thinning flow in the high shear rate range and the pastes with bad dispersion characteristic demonstrated higher shear-thinning index than those with good dispersity due to the weak flocculated network structure. The output curve of OTFT device with a channel length of 107 ${\mu}m$ using screen-printed S-D electrodes from DT-30 showed good saturation behavior and no significant contact resistance. And this device exhibited a saturation mobility of $4.0{\times}10^{-3}$ $cm^2/Vs$, on/off current ratio of about $10^5$ and a threshold voltage of about 0.7 V.

• 한국조리학회지
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• 제21권6호
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• pp.182-194
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• 2015

본 연구에서는 첨차를 분말화하여 쿠키에 첨가하고, 그 품질 특성 및 항산화특성을 측정하여 저열량 쿠키의 최적 배합비를 개발하고자 하였다. 첨차 분말의 첨가량이 증가함에 따라 쿠키의 퍼짐성과 수분함량, 수용성 고형분 함량, 경도 측정 결과값이 높아졌으며, 쿠키 반죽의 pH는 감소하였다. 색도 측정 결과 첨차 분말 첨가량에 따라 L값과 황색도가 감소하였고, 녹색도가 증가하였다. 쿠키의 항산화특성으로 첨차 분말 첨가량이 많아질수록 총 페놀성화합물과 DPPH 자유 라디칼 소거능 모두 증가하였으며, 양적 상관관계를 나타냈다(R=0.976). 기호도 조사 결과 6% 첨가구에서 전반적인 기호도가 가장 높았으며, 6% 이상 첨가구에서 첨가량에 따라 값이 감소하였다(p<0.001). 따라서 첨차를 첨가하여 설탕의 사용량을 감소시킨 쿠키의 제조가 가능하며, 6%의 첨가 수준을 설정할 수 있을 것으로 판단된다.

• 한국분말재료학회지
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• 제22권2호
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• pp.100-104
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• 2015

The porous metals are known as relatively excellent characteristic such as large surface area, light, lower heat capacity, high toughness and permeability. The Fe-Cr-Al alloys have high corrosion resistance, heat resistance and chemical stability for high temperature applications. And then many researches are developed the Fe-Cr-Al porous metals for exhaust gas filter, hydrogen reformer catalyst support and chemical filter. In this study, the Fe-Cr-Al porous metals are developed with Fe-22Cr-6Al(wt) powder using powder compaction method. The mean size of Fe-22Cr-6Al(wt) powders is about $42.69{\mu}m$. In order to control pore size and porosity, Fe-Cr-Al powders are sintered at $1200{\sim}1450^{\circ}C$ and different sintering maintenance as 1~4 hours. The powders are pressed on disk shapes of 3 mm thickness using uniaxial press machine and sintered in high vacuum condition. The pore properties are evaluated using capillary flow porometer. As sintering temperature increased, relative density is increased from 73% to 96% and porosity, pore size are decreased from 27 to 3.3%, from 3.1 to $1.8{\mu}m$ respectively. When the sintering time is increased, the relative density is also increased from 76.5% to 84.7% and porosity, pore size are decreased from 23.5% to 15.3%, from 2.7 to $2.08{\mu}m$ respectively.

• 대한치과기공학회지
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• 제40권3호
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• pp.125-131
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• 2018

Purpose: Automatic dental prosthesis manufacturing process was accelerated by the spread of dental CAD / CAM system. The CAD / CAM system with milling alloys were needed supplement. So, sintered alloy blocks were introduced. In this study, we want to study sintered alloy block. And to evaluate the alloy block manufacture and alloy properties. Methods: The alloy powders were prepared by high pressure water dispersion method. The sintered alloy blocks were prepared by low temperature pressing method. Their components observation were EDX, and the alloy structure was observed by XRD. Results: Co-Cr alloy powders were observed to have a circle shape with an average diameter of about $100{\mu}m$ and a Ni-Cr alloy powder had a circle shape with an average diameter of about $50{\mu}m$. The Co-Cr alloy block is composed of Co (34.62 wt%), Cr (17.33 wt%), Mo (2.98 wt%), Si (0.36 wt%) and C (44.17 wt%). The Ni-Cr alloy powder was composed of Ni (40.29 wt%), Cr (19.37 wt%), Mo (3.53 wt%), Si (0.52 wt%) and C (33.18 wt%). The peak of the Co and CoCr peaks were observed in the CoCr alloy body by the means of XRD study. Cr2Ni3 of the peak was observed in the Ni-Cr alloy material. Conclusion : As a result, the following conclusions were obtained. 1. Prepared by high-pressure water-law Co-Cr alloy powder has an average diameter $100{\mu}m$, Ni-Cr alloy powder was found to have the form of sphere having an average diameter $50{\mu}m$. 2. Co-Cr alloy and Ni-Cr alloy block produced by low-temperature processing showed a certain ratio. 3. In the XRD study, Co phase appeared in Co-Cr alloy block after sintering. and Cr2Ni3 phase appeared in Ni-Cr alloy block after sintering.

• 한국세라믹학회지
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• 제22권5호
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• pp.9-16
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• 1985

Agglomeration of Y-PSZ and its related properties were studied. The ultrafine $ZrO_2$ powder containg 3 mol% $Y_2O_3$ was prepared by 1) coprecipitation method b) hot petroleum drying method c) sol-gel method and the characteristics of calcined powders and the microstructures of sintered body were observed. Powder prepared by the coprecipitation method was about 125$\AA$ in crystallite size and 0.1~1.0${\mu}{\textrm}{m}$ of intra-agglomerate pore size when calcined at $600^{\circ}C$ for 1 hour. because of small crystallite size and weak agglo merate strength resultant densification of sintered body was high. But above the temperature of 130$0^{\circ}C$ efflorescent phenomena due to anions attached to powder surface was observed. Powder prepared by hot petroleum drying method was 65$\AA$ in crystallite size and 1~10${\mu}{\textrm}{m}$ of intraagglome-rate pore size and it was observed that the agglemerates were formed during the calcining process. In this case despite of small crystallite size the rate of sintering was slow and the existing lenticular interagglomerate pore was not eliminated to the final stage of sintering. Powder prepared by sol-gel method showed solid agglomertes due to rapi dhydrolysis reaction. In this powder which involves strong solid agglomerates overall sintering rate was determined by the sintering between the agglomerates and therefore sinterability of powders made by sol-gel method was very poor.

• 한국조리학회지
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• 제20권6호
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• pp.28-40
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• 2014

본 연구는 일반적으로 햄버거 패티 제조 시에 사용하는 빵가루를 대신하여 두부분말(빵가루 양 대비 25%, 50%, 75%, 100%)을 첨가하여 햄버거 패티를 제조하고, 품질 특성, 관능특성을 평가하였다. 결과는 다음과 같다. 햄버거 패티에 두부분말의 첨가량 증가에 따라 pH가 증가하는 경향을 나타내었다. 대조구의 수분함량은 두부분말 첨가 햄버거 패티보다 높았다. 햄버거 패티의 두부분말의 증가에 따라 수분함량은 감소하였다. 가열 중량 감소율은 유의적인 차이가 나타나지 않았으며, 두부분말의 첨가에 따라 직경 감소율은 감소하고, 두께 감소율은 증가하였다. 두부분말의 첨가는 햄버거 패티의 명도(L값), 적색도(a값), 황색도(b값)를 증가시켰다. 조직감 특성에서는 두부분말의 첨가가 햄버거 패티의 경도, 탄력성, 검성을 증가시켰다. 관능특성에서는 두부분말 100% 첨가구가 외관, 맛, 전반적인 기호도에서 가장 우수한 점수를 나타내었다. 그러므로 본 연구결과를 통하여 햄버거 패티의 제조 시, 빵가루 대비 두부분말 100% 첨가가 햄버거 패티의 기호도와 영양적인 측면에서 적합할 것으로 사료된다.