• 한국수산과학회지
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• 제27권5호
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• pp.476-481
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• 1994

액젓 제조시 발효를 촉진하기 위하여 정어리를 기질로한 코오지를 제조하고 이것으로 부터 추출한 조효소액인 lipase의 pH 및 온도의존성과 코오지의 구성지질 및 지방산 조성을 조사하였다. Lipase의 최적 활성을 나타내는 pH는 $7{\sim}8$이었으며 pH 5.0 이하와 9.0 이상이 되면 활성은 급격히 감소하였고, 최적온도는 $40^{\circ}C$ 부근이였다. pH 및 온도에 변화에 따른 활성잔존율을 조사한 바 pH $6{\sim}9$ 범위에서 $90{\sim}100\%$, $40^{\circ}C$에서 1시간 가열처리했을때 약 $80\%$의 잔존율을 보였고 $50^{\circ}C$ 이상이 되면 잔존율은 크게 감소하여 $50^{\circ}C$는 $10\%$, $60^{\circ}C$는 $3\%$의 잔존율을 보였다. 코오지 지질 조성은 중성지질은 triglyceride가 $53.4\%$ 유리지방산은 $28.1\%$로 전체 중성 지질의 $81.5\%$를 차지하였고 인지질은 phosphatidylethanol이 $32.7\%$로 가장 높았고 그 다음이 phosphatidylinositol이 $25.5\%$, phosphatidylcholine이 $25.1\%$였고 그 외 lyso-phosphatidyl-choline, sphingomyeline 등도 $7.3\%$와 $3.5\%$정도 함유되어 있었다. 한편 총지질과 중성지질의 주요 지방산은 16:0, 22:6, 18:1n-9, 18:2n-6 및 20:5이였고 인지질의 경우는 22:6이 중성지질에 비해 월등히 높게 나타났고 그 다음이 16:0, 18:2n-6 및 20:5로 나타났다.

• 마이크로전자및패키징학회지
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• 제23권4호
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• pp.43-48
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• 2016

3-Dimensional System in Package (3-D SiP) structure (Amkor calls it mPossum-molded Possum) using double side Surface Mount Technology (SMT) and double side molding was evaluated in order to achieve small/thin form factor as well as good functionality by integration and double side layout. As the new platform on laminate substrate basis, molding process was challenge in mold flow balance at top and bottom side and package warpage control over the overall assembly process. There were two types of different molding process evaluated with 1) 1-step molding which was done at both side at the same time and 2) 2-step molding which was done at the conventional molding process twice. Mold simulation helped to narrow down the material selections and parameters available before actual sample build. There were many challenges for this first trial in design/ parameter and material types but optimized them to enable this structure.

• Design & Manufacturing
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• 제10권2호
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• pp.18-23
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• 2016

Injection molded thermoplastic parts may need to be coated to facilitate paint adhesion, or to satisfy other surface property requirements, such as appearance, durability, and weather resistance. In this paper, a two-component polyurethane metering system was developed for the simultaneous injection and surface coating of a plastic substrate. The system was composed of storage tanks, feed pumps, axial piston pumps, mixing head. The tank was designed to be double-jacket structured and fabricated for polyol and isocyanate, respectively. A temperature chamber was used to maintain the material temperature to be $80^{\circ}C$ during flowing from storage tank to mixing head. Inside the chamber, feed pump, low pressure filter, high pressure pump, high pressure filter, pressure sensor, flow meter were installed. A mixing head of L-type was used for homogeneous mixing of polyol and isocyanate. Inside the mixing head, a cartridge heater and a temperature sensor were installed to control the temperature of the materials. The flow rate of axial-piston pump was controlled by using closed-loop feedback control algorithm. The input flow-rates were compared with the measured values. The output error was 6.7% for open-loop control, whereas the error was below 2.2% for closed-loop control. In addition, the pressure generated through mixing-head nozzle increased with increasing flow rate. It was found that the pressure drop between metering pump and mixing-head nozzle was almost 10 bar.

• 마이크로전자및패키징학회지
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• 제22권2호
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• pp.61-68
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• 2015

박형 package-on-package의 상부 패키지와 하부 패키지에 대하여 에폭시 몰딩 컴파운드(EMC)에 따른 warpage 특성을 분석하였다. 또한 동일한 EMC로 몰딩한 패키지들의 warpage 편차를 측정하고 박형 상부 기판과 하부 기판 자체의 warpage 편차를 측정함으로서, 박형 패키지에서 warpage 편차를 유발하는 원인을 분석하였다. 박형 기판을 사용한 상부 및 하부 패키지에서는 기판 자체의 큰 warpage 편차에 기인하여 EMC의 물성이 패키지의 warpage에 미치는 영향을 규명하는 것이 어려웠다. EMC의 몰딩 면적이 $13mm{\times}13mm$로 기판($14mm{\times}14mm$)의 대부분을 차지하는 상부 패키지에서는 온도에 따른 warpage의 변화 거동이 유사하였다. 반면에 EMC의 몰딩 면적이 $8mm{\times}8mm$인 하부 패키지의 경우에는 (+) warpage와 (-) warpage가 한 시편에 모두 존재하는 복합적인 warpage 거동에 기인하여 동일한 EMC로 몰딩한 패키지들에서도 상이한 온도-warpage 거동이 측정되었다.

• 한국자동차공학회논문집
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• 제22권5호
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• pp.20-28
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• 2014

The high velocity oxygen fuel spraying (HVOF) is a kind of surface modification process technology to form the sprayed coating layer after spraying the powder to molten or semi-molten state by the ultra-high speed at the high-temperature heat source and conflicting with a substrate. It is desirable to melt completely the thermal spray powder in order to produce the coating layer with an optimal adhesion, however, because a semi-molten powder in a spray process has the low efficiency and become a factor that degrades the mechanical property by the inducement of pore-forming within the coating layer. To improve the wear resistance, corrosion resistance and heat resistance, in this study, the plungers of high-speed and ultra-high pressure reciprocating hydraulic pumps for oil and water used in ironwork are produced with $420J_2$ and the coating layers of plungers are formed by the powders of WC-Co-Cr and WC-Cr-Ni including the high hardness WC. The surface of these plungers is modified by the super-mirror face grinding machine using variable air pressure developed in this laboratory, and then the characteristics of cross-sectional microstructure, and surface roughness and hardness values between no operation and 100 days-operation are examined and made a comparison. The fine tops and bottoms on surface roughness curve of oil-hydraulic pump plunger sprayed by WC-Cr-Ni are molded more and higher than those of water-hydraulic pump sprayed by WC-Co-Cr because the plunger diameter of oil-hydraulic pump is 0.4 times smaller than that of water-hydraulic pump and the pressure of oil-hydraulic pump exerted on the plunger is operated with the 70 bars higher than that of water-hydraulic pump. As a result, it is found that the values of centerline average surface roughness and maximum height for oil-hydraulic pump plunger are bigger than those of water-hydraulic pump plunger.

• 접착 및 계면
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• 제21권3호
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• pp.101-106
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• 2020

본 연구에서는 에폭시 수지를 개질 한 변성 아크릴레이트를 합성하였으며, 이를 기존의 유리 섬유 복합소재에 사용하는 SMC 조성물에 5 phr - 15 phr을 첨가하여 SMC 소재를 제조하였다. SMC 프리프레그를 고온고압 (150 ℃, 10 bar)에서 컴프레션 몰딩방법으로 성형하여 유리섬유 복합소재를 제조하였으며, 제조된 복합소재를 가공하여 인장강도, 충격강도 등의 기계적 물성을 연구하였다. 실험 결과 합성된 변성 아크릴레이트를 5 phr을 포함하는 복합소재가 합성 아크릴레이트를 포함하지 않는 binder 샘플보다 인장강도는 약 20%, 충격강도는 약 12% 향상함을 보였으며, 이는 합성 아크릴레이트가 폴리에스터와 반응할 수 있는 4개의 아크릴 기를 가짐으로써 가교반응을 강하게 하면서 기계적 강도가 향상됨을 확인하였다.