• Applied Chemistry for Engineering
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• v.21 no.4
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• pp.411-416
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• 2010

In this research, we intended to improve the tolerance of thick film resistor using photosensitive polymer resistor paste which was fabricated with alkali-solution developable photosensitive resin and conductive carbon black. At first, we investigated the effect of the selection of carbon black and photosensitive resin on the resistance range and tolerance level of polymer thick film resistor (PTFR). And then, a difference in resistance tolerance was evaluated according to the coating methods of photosensitive resistor paste on test board. In case that the photosensitive resistor paste was coated on whole surface of test board using screen printing, large positional tolerance was obtained because the formation of the thick film with uniform thickness was difficult. On the other hand, when the paste was coated with roller, the resistive thick film with uniform thickness was formed on the whole board area and the result of resistance evaluation showed low tolerance in ${\pm}10%$ range. The tolerance of PTFR could be improved by combination of the precise patterning using photo-process and the coating process for the resistive thick film with uniform thickness.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.291-294
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• 2001

합섬직물의 경사줄 발생은 업계에서는 해결해야할 품질사고 중에서 가장 중요하며 경사줄 발생 불량만 해결하여도 품질사고의 90％이상은 해결 할 수 있는 중요한 직물 품질평가항목1)~3)이다. 이러한 합섬직물의 경사줄 발생은 공정에서 주어지는 장력과 열처리를 사가 받으면서 발생하게되며 발생할 수 있는 원인은 원사의 이상에서부터 각 공정에서의 원사물성에 따른 공정관리가 잘 못 될 때 발생의 소지가 많게 된다. (중략)

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2007.11a
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• pp.79-80
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• 2007

연속 동판재 생산을 위하여 전주도금 기술과 고속동도금 기술을 응용하여 동도금 공정을 개발하였다. 동 연속 전주 장비를 개발하고 적절한 동도금 조건의 개발을 통하여 연속적인 동도금 판재의 생산이 가능하게 하였다. 연속 전주 장치에서 제작된 동판재의 최종 물성을 살펴보면 두께 형성 속도는 $20{\mu}m/min$. 속도이고, 동판재의 두께 편차는 5%이내의 두께 편차를 나타내었다. 제작된 동 판재의 비저항은 $2.2{\times}10-6\;{\Omega} cm$를 나타내었으며, SEM을 이용한 표면관찰에서 void-free한 형태를 나타내었다. 판재상의 피막의 불순물은 500ppm 이하의 물성을 나타내었다.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.06a
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• pp.43-50
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• 2004

• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.2
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• pp.186-193
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• 2002

A new integrated torque and speed control algorithm has been proposed for the load balancing of rollers in continuous strip processing line(CSPL). Using the proposed method, the output torque and speed can be controlled to follow the reference in spite of nonideal effects such as the speed reference error and/or the controller gain difference between rolls. This new algorithm can be easily implemented in a motor drive system of each roll as it does not require the torque feedback of the others. Through the simulation and experiments for a simple CSPL consists of four driven rolls, the load balancing performance of the proposed scheme is presented and compared with that of conventional method.

• Journal of the Microelectronics and Packaging Society
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• v.19 no.3
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• pp.57-62
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• 2012

In this paper, numerical analysis by finite element method, parameter design by the Taguchi method and ANOVA method were used to analyze about effect of design deviations and thickness variations on warpage of FCCSP substrate. Based on the computed results, it was known that core material in substrate was the most determining deviation for reducing warpage. Solder resist, prepreg and circuit layer were insignificant effect on warpage relatively. But these results meant not thickness effect was little importance but mechanical properties of core material were very effective. Warpage decreased as Solder resist and circuit layer thickness decreased but effect of prepreg thickness was conversely. Also, these results showed substrate warpage would be increased to maximum 40% as thickness deviation combination. It meant warpage was affected by thickness tolerance under manufacturing process even if it were met quality requirements. Threfore, it was strongly recommended that substrate thickness deviation should be optimized and controlled precisely to reduce warpage in manufacturing process.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1999.11a
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• pp.3-9
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• 1999

IGCC(Integrated Gasification Combined Cycle)에서 석탄가스화기는 기존 석탄화력발전소의 보일러를 대체하는 설비로서, 석탄가스화 공정의 해석은 매우 중요하다고 할 수 있다. 석탄가스화 공정은 탄종과 운전조건에 따라 반응특성의 편차가 매우 크기 때문에 탄종별 가스화 특성에 대한 정보의 확보는 필수적이라 할 수 있다. 그러나 국내에는 수입되는 다양한 석탄에 대한 가스화 특성에 대한 정보가 없는 실정이다.(중략)

• The Korean Journal of Rheology
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• v.9 no.2
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• pp.66-72
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• 1997

사출성형품의 품질특성으로 외관, 치수, 기계적 강도 등이 있으나 조립부품으로써 사 될경우에는 치수가 주요한 품질이 된다. 성형품은 용융수지의 특성상 사출공정 중 수축을 일으키므로 이를 고려해서 금형설계가 이루어지지만 실제 사출과정에서 공정변수를 최적화 하여 관리하지 않으면 허용오차 내의 치수를 얻기가 힘들다. 본 논문에서는 주요조립부의 치수가 허용오차 내에서 얻어지도록 설계시 적용된 수축률과 측정된 수축률의 차이를 목적 함수로 하여 최소화 시키며 반복이차계획 알고리즘을 채택한 IDESIGN 프로그램을 이용해 최적 사출성형조건을 구하였다. 제약조건은 성형품의 부위별 수축률 편차 및 싱크마크 깊이 가 공정변수의 부등호 제약식으로 도출되었고 성형이 이루어지는 공정변수의 상하한 값이 최대 및 최소 경계값으로 적용되었다.

• Proceedings of the Korean Fiber Society Conference
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• 2001.10a
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• pp.295-298
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• 2001

합섬필라멘트사의 경우 방사 공정이후 공정에서 받는 열처리 조건은 우선 반연 공정에서 16$0^{\circ}C$~18$0^{\circ}C$ 정도의 건열처리가 주어지고, 다음 sizing 공정에서 8$0^{\circ}C$~10$0^{\circ}C$의 습열처리, 그리고 sizing 후 dry chamber에서 10$0^{\circ}C$~15$0^{\circ}C$의 열풍이 주어진다. 그리고 2-for-1 공정을 거친 후 steammer에서 7$0^{\circ}C$~9O$^{\circ}C$ 정도의 스팀 습열처리가 주어진다. (중략)

• The Journal of the Acoustical Society of Korea
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• v.35 no.6
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• pp.436-444
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• 2016

Uniformity in transducer performance is a must-have to ensure the reliable acoustic performance of a tile projector, used for active echo reduction. However, practical limitations imposed by variations in material properties and fabrication errors lead to performance variations among unit transducers, which could degrade the radiation characteristics (transmitting voltage response and directivity) of the tile projector and ultimately the echo reduction performance. In this paper we present a method to minimize these adverse effects via an appropriate placement of unit transducers within the tile projector. To this end, we perform a series of coupled acoustic-piezoelectric simulations, assuming a group of 36 unit transducers having 6 dB variations in transmitting voltage response, to analyze and compare the radiation characteristics of tile projectors under different transducer placement schemes.