• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.2
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• pp.1-8
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• 2016

Generally, electrical circuits are fabricated as Printed Circuit Boards (PCBs) and mounted on the casing of the product. Additionally, this requires many other parts and some labor for assembly. Recently, molding technology has increasingly been applied to embed simple circuits in plastic casing. The technology is called a Molded Interconnected Device (MID). By using this technology, PCB fabrication can be replaced by molding, and much of the corresponding assembly process for PCBs can be eliminated if the circuit is simple enough for molding. Furthermore, as the improvement of conductive materials and printing technologies of simple electric circuits can be printed directly on the casing part, this also reduces the complexity of the product design and production cost. Therefore, this paper introduces a new MID fabrication process using direct 3D printing technology. Additionally, it is applied to an automotive part of a cruise control switch. The methodology and design are shown.

• Journal of the Korean Geophysical Society
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• v.2 no.3
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• pp.225-233
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• 1999

Electrical resistivity of a rock-sample is dependant on not only formation factor of rock itself but also many parameters such as fluid type, measuring device, temperature, water saturation, electrical contact between electrode and core section, induced polarization, and frequency of electric source. In this study, we attempt to verify various affecting factors in core resistivity measurements and to find a better environment for core resistivity measurement. Particularly great attention has been paid to understanding the effects of temperature, water saturation, contact condition between sample and electrodes, and frequency of electric source. Precise measurement of resistivity can be achieved by utilizing silver paste for better contacts, taping samples for constant moisture contents, and using time-series resistivity data.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.06a
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• pp.40-41
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• 2006

In this work, we developed the 0-3 type piezoelectric composite to incorporate the advantages of both ceramic and polymer. The PVDF-PZT composites were fabricated with various mixing ratio by 3-roll mi11 mixer. The composite solutions were coated on ITO bottom-electrode deposited on PET (polyethylene terephthalate) polymer film by the conventional screen-printing method. After depositing the top-electrode of silver-paste, 4kV/mm of DC field was applied at $120^{\circ}C$ for 30min to poling the 0-3 composite film. The value of $d_{33}$ was increased as the PZT weight percent was increases. But the $g_{33}$ value showed the maximum at 65 wt% of PZT powder.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.4
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• pp.242-245
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• 2021

In this work, we fabricated oxide on an n-type silicon substrate through local anodic oxidation (LAO) using atomic force microscopy (AFM). The resulting oxide thickness was measured and its correlation with load force, scan speed and applied voltage was analyzed. The surface oxide layer was stripped using a buffered oxide etch. Ohmic contacts were created by applying silver paste on the silicon substrate back face. LAO was performed at approximately 70% humidity. The oxide thickness increased with increasing the load force, the voltage, and reducing the scan speed. We confirmed that LAO/AFM can be used to create both lateral and, to some extent, vertical shapes and patterns, as previously shown in the literature.

• Journal of Korean Society of Archives and Records Management
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• v.3 no.1
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• pp.1-21
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• 2003

In this paper the characteristics of the script centers golden and/or silver letter center in Koryo Dynasty and a set of seven rolls of the script written in silver letter on blue paper prayed by Yearn Seong-Ik were studied with focusing on the referred records and an epilog of the script. This script was discovered from Namgewon's stone stupa, when it was transported from original site of Daekam Dong, Kaiseong city to Kyungbok Palace in 1919. This script prayed by Yeom Seong-Ik which was written in silver paste on blue papers is a set of seven rolls, the size is 31.1 cm (length) ${\times}$ 27.2 cm (width). The cover painting and Beonsangwha(Buddha's preaching picture) were painted out and in the roll cover. This script was written with 14 letters on a line whose characteristic with the style of cover painting and Beonsangwha is similar to the golden and silver scripts prayed by kings of Koryo Dynasty. The person who prayed this script was a powerful vassal of the king Chungyeol period, Yeom Seong-Ik. According to Koryosa(Koryo History) and Koryosa jeolyo(summarized Koryo History), it is described that Yeom Seong-Ik offered his own house which was built by a group of strangers as a 'Writing Place for the complete collection of Buddhist Sutras and the place of the script of the complete collection of Buddhist Sutras. Therefore, it is possible to consider that this script a set of seven rolls of the script of Saddharma Pundarika-Sutra was written to pray for himself as well as his families' fortune at the place of golden script of the complete collection of Buddhist Sutras, and enshrined it in the Namgaewon stone stupa when the stupa was repaired in 9th year of king ChungYeol. Above all the most important point should be centered on that he offered his house as a writing place for golden script of the complete collection of Buddhist Sutras as recorded in Koryosa Jeolyo. The writing place for golden script of the complete collection of Buddhist Sutras should be emphasized on the meaning of its site. It is an important key point to clear that Kumjawon(Golden letter center) would be different from Kumjadejangso(the writing place of golden script for complete collection of Budihist Sutras) with Kumkyungsa(Goldm script place). As considereing the point that this script showed the characteristics of golden and/or silver scripts which prayed by king Chungyeol in Koryo Dynasty as they were, even though this script was manufactured by individual praying, this script follwed in the style of Kumjawon(golden letter center) and/or Unjawon(siIver letter center) as they were, because this script was written in the place of the golden script for the complete collection of Buddhist Sutras. In this paper all of the points described above with focusing on the referred records and an epilog of this script were collectively considered to make clear the characteristics of the script centers, golden and/or silver letter.

• Journal of Korean Society of Archives and Records Management
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• v.1 no.2
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• pp.159-183
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• 2001

The praying sentences of the script of Saddharmapundarika-sutra NO.5 which was made by prayer Bang-Ui, prince Ik-An, was investigated and the cover painting, Byonsangwha(Buddha's preaching painting), and letter style written in the script were discussed in this study. The cover painting on the script is known to be followed to the style of the cover painting as shown in a set of 7 rolls of Saddharma pundarika-sutra of the Horim Museum collection. It is not so difficult to say that the characteristics of cover painting of the script would be suceeded to those of scripts of the end of Koryo and the early Choseon Dynasty. Lotus and its surround was decorated with arabesque figure whose stems were drawn with golden paste and the arabesque figures were done with silver paste. However, for the expression of lotus and arabesque pattern the special feature of drawing style that was originated from the end of Koryo Dynasty to draw the outline with broad line and/or the hardness of drawing line became much more deepened than ever. It is not different to think that this characteristics should be those of Choseon Dynasty. On the Byeonsangwha(buddha's preaching painting) the painting of scattered flowers on stairs of Sumera-Mandala and the scheduled clouds (underseen from heaven) were as similar as to the Byeonsangwha style of the end of Koryo and the early Choseon Dynasty. However, the image of Shakyamuni and/or the halo(光背) is nearly same as the characteristics shown on the Beonsangwha of Saddharma pundarika-sutra of Nesosa' collection, a set of seven rolls which was completed in the 15th year of king Taejong(AD 1415). It is apparent that these characteristics are those of Choseon Dynasty. After king Chungsean in Koryo Dynasty, letter style of Chao Meng-Fu was shown in the script of late Koryo Dynasty as a new letter style.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.4
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• pp.1879-1884
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• 2014

Recently, the micro bonding technology comes into the spotlight as the miniaturization of the electronic product. The micro bonding technique can classify by way of laser welding and ultrasonic bonding and etc. However, the research on the micro bonding is much lacks. In this paper, carried out the cooling analysis of the 60 [kHz] ultrasonic bonding equipment to know heat effect of the piezoelectric element when the ultrasonic bonding equipment was operated. The ultrasonic horn having the natural frequency with 60 [kHz] for the dissimilar material bonding of the glass and solder tried to be designed. The parameters and response was set through the basic experiment. The dissimilar material bonding strength analysis using the 60 [kHz] ultrasonic bonding equipment was done. We carried out the bonding for improving bonding strength to using the silver paste. air thightness of bonding surface was confirmed by analysis of bonding interfaces.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.11a
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• pp.83-83
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• 2009

우수한 압전성을 가지는 PZT는 인체에 유해한 다량의 PbO을 함유하여 심각한 환경문제를 야기함은 물론 제조 공정 중 PbO 휘발 억제 시설 구비에 따른 경제적 부담 등 문제점이 지적되었다. 따라서 환경오염 및 가격경쟁력을 갖추기 위해 현재 무연 조성 세라믹스에 대한 많은 연구가 진행되고 있다. 최근 비납계 압전 세라믹의 연구는 비스무스 레이어형과 페로브스카이트 형 비납계 세라믹스의 연구가 활발히 진행되고 있다. 특히 $(Na,K)NbO_3$ 계는 페로브스카이트 구조를 가지는 비납계 세라믹으로 현재 많은 연구가 진행되고 있다. 이 물질은 PZT계와 유사하게 상전이(morphotropic phase boundary:MPB)영역을 가지고 있 으며 이 영역에서 높은 압전 특성을 보여주고 있다. 최근 $Na_{0.5}K_{0.5}NbO_3$에 $LiTaO_3$를 치환하여 우수한 압전 특성을 지니는 조성이 개발되고 있지만, 보통 소성법으로 제조된 세라믹스는 PZT계 세라믹스와 비교하여 특성이 떨어진다. 본 연구에서는 압전성이 우수한 $(Na_{0.44}K_{0.52}Li_{0.44})(Nb_{0.90}Sb_{0.06}Ta_{0.04})O_3$ 조성에 도너 도핑과 억셉터 도핑을 한 다음 전기기계결합계수, 압전상수, 유전상수의 변화를 평가하고, hardener 와 softener 특성이 본조성에서 나타나는지를 관찰하였다. 실험방법은 보통 소성법을 사용하였으며, 분쇄와 혼합은 직경 3 mm zirconia ball을 사용하여 볼밀 하였다. $850^{\circ}C$ 에서 5h 하소 후 $1100{\sim}1200^{\circ}C$ 에서 소결하고, 두께 1 mm로 연마한 다음 silver paste를 $650^{\circ}C$ 에서 소부하여 전극을 형성하였다. 제작된 시편은 $90^{\circ}C$의 실리콘유에서 3~4 kV/mm의 전계를 가해 20분간 분극 처리를 수행하였다. 제작된 시편의 압전전하 상수 값은 d33-meter(APC-8000)를 이용하여 측정하였고, 유전율, 전기기계결합계수 및 기계적품질계수 등은 임피던스 분석기 (impedance/gain phase analyzer)를 이용하여 특성을 측정 하였다. 또한 전압-분극 특성의 평가에는 강유전특성 측정기(ferroelectric tester: Precision-LC, Radiant Technologies, USA)를 이용하였다.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.9
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• pp.322-327
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• 2012

Parallel-plate-type scanning sensors have been commercially used for X-ray imaging sensors. In this study, we manufactured the scan typed 1D X-ray image sensor that can be used to obtain scanning images, by using the plasma display panel (PDP) fabrication process. We fabricated drift and pixel electrodes in the glass chamber and injected Xe gas at atmospheric pressure. We evaluated the intensity of a pixel signal depending on the bias voltage on the drift electrode and investigated the characteristics of shielding effect on the single pixel using lead (Pb). The adsorption rate of X-ray photon is low (4%) on the soda lime glass (1.1mm) and the electrical signal detected on the X-ray sensor was increased in the high bias voltage. We acquired digital X-ray scanning image with our DAS (data acquisition system) and sensor scanning system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.10
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• pp.1069-1074
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• 2014

In this study, the piezoelectric characteristics of a piezoelectric paint sensor were investigated in relation to the poling time. This piezoelectric paint sensor was composed of PNN-PZT powder and epoxy resin with a 1:1 weight ratio. The dimensions of the paint specimen were $40{\times}10{\times}1mm^3$, and the top and bottom sides were both coated with a silver paste to create electrodes. During the poling treatment, the poling time was controlled to examine the effect of the piezoelectric properties, while the poling temperature was fixed at room temperature and the electric field was set to 4 kV/mm. The piezoelectric properties were measured by comparing the output voltage from the paint sensor to the force signal from an impact hammer when the impact hammer hit the specimen. In conclusion, the optimal poling conditions were found to be an electric field of 4 kV/mm and a poling time of around 30 min at room temperature.