• 대한전자공학회논문지SD
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• 제43권11호
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• pp.8-13
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• 2006

최근 RF용 탄성표면파 필터는 HTCC 패키지를 이용한 칩스케일 패키지 공법으로 제작되고 있다. 본 연구에서는 HTCC 패키지를 이용하는 대신에 BT 레진 계열의 PCB 기판을 이용하여 $1.4{\times}1.1$과 $2.0{\times}1.4mm$ 규격을 가지는 새로운 SAW RF 필터를 개발하였다. 본 기술을 적용하여 기존대비 약 40% 이상의 재료비 절감효과를 얻을 수 있다. 다층 PCB 기판과 $LiTaO_3$ 탄성표면파 기간간의 플립 본딩 조건을 최적화하였고, 적절한 PCB 재료선정을 통하여 PCB 기판 및 에폭시 라미네이팅 필름간의 열팽창계수 차이로 인해 발생하는 응력을 최소화시켰다. 이렇게 개발된 탄성표면파 필터는 기존의 제품에 비해 신뢰성 및 전기적 특성면에서 향상된 특성을 보였다.

• 한국전기전자재료학회논문지
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• 제25권8호
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• pp.593-601
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• 2012

Ordered mesoporous oxide films have been focused because of their low density, high interior specific surface area, and high thermal insulation. Specially, the ordered mesoporous oxide films prepared by self-assembly has many advantages due to easy process and high reproducibility. In this work, ordered mesoporous $SiO_2$, $Al_2O_3$, and $TiO_2$ films were synthesized by control of composition and processing parameter. Also, their structural, thermal, and mechanical properties were characterized variously. In conclusion, ordered mesoporous oxides will be one of core materials in new technology due to their excellent and unique properties.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.569-573
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• 2004

RAINBOW(Reduced And Internally Biased Oxide Wafers) are a new class of high-displacement, piezoelectric actuator produced by selectively removing oxygen from one surface of ceramic using a high-temperature chemical reduction process. In this paper, RAINBOW composition of 0.4Pb$(Ni_{1/3}Nb_{2/3})O_3-0.6Pb(Zr_xTi_{1-x})O_3$ were prepared. Its dielectric and piezoelectric properties were investigated in the vicinity of MPB. The strain - electric field characteristics of RAINBOW actuator were significantly improved comparison with the conventional bulk actuator.

• 세라미스트
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• 제21권2호
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• pp.59-74
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• 2018

Imaging in the Short Wave Infrared (SWIR) provides several advantages over the visible and near-infrared regions: enhanced image resolution in in foggy or dusty environments, deep tissue penetration, surveillance capabilities with eye-safe lasers, assessment of food quality and safety. Commercially available SWIR imagers are fabricated by integrating expensive epitaxial grown III-V compound semiconductor sensors with Si-based readout integrated circuits(ROIC) by indium bump bonding Infrared image sensors made of solution-processed quantum dots have recently emerged as candidates for next-generation SWIR imagers. They combine ease of processing, tunable optoelectronic properties, facile integration with Si-based ROIC and good performance. Here, we review recent research and development trends of various application fields of SWIR image sensors and nano-materials capable of absorption and emission of SWIR band. With SWIR sensible nano-materials, new type of SWIR image sensor can replace current high price SWIR imagers.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.87-88
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• 2006

Ceramic-Metal Functionally Graded Materials (FGM) are of great interest for application as Thermal Barrier Coating (TBC) or Wear Resistant Coating (WRC). Spark Plasma Sintering (SPS) is a promising techniques for time-saving consolidation of laminated/graduated powder systems: SPS is a pressure-assisted electrical sintering method which directly applies a pulsed DC current as heat source. In the present work, production of $Al_2O_3-Ni$ FGMs by means of Spark Plasma Sintering is considered; effect of sintering condition on density, hardness and fracture toughness is studied. Problems correlated to this new processing technology are discussed.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 하계학술대회 논문집
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• pp.814-819
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• 2000

The progress in the field of electronic materials has been especially significant for applications involving a range of electrical properties. Its importance is increasing with the increasing demand for integrated circuits. The sol-gel technique has been used for many years, and the metal alkoxides have featured prominently as source materials. The method consist of making a homogeneous solution of the component metal alkoxides in a suitable solvent, usually the parent alcohol; and then causing the hydrolysis under controlled conditions to produce a gel containing the hydrated metal oxide. The gel is then dried, and fired to produce a ceramic or glassy material at a temperature much lower than that required by the conventional melting process. This project consists of important theoretical considerations, processing techniques and applications related to electrophoresis derived thin films. In the electrophoretic process a metal alkoxide solution is gelled through hydrolysis-polymerization and converted the gel thin layer to an oxide by heating at relatively low temperatures.

• 한국세라믹학회지
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• 제41권4호
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• pp.313-322
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• 2004

후막 광식각 기술은 스크린 인쇄 등의 일반적인 후막공정에 노광 및 현상 등의 리소그라피 공정을 접목시킨 새로운 기술이다. 본 연구에서는 후막 광식각 기술을 이용하여 미세라인을 형성할 수 있는 저온동시소성용 Ag 페이스트를 개발하였다. 페이스트를 구성하는 Ag분말과 폴리머, 모노머, 광개시제 등의 양을 조절하여 미세라인을 형성할 수 있는 최적 조성을 연구하였으며. 또한 노광량과 같은 공정변수가 미세라인 형성에 미치는 영향을 연구하였다. 실험결과 폴리머/모노머비, Ag 분말 중량비, 광개시제의 양 등이 미세라인의 해상도에 영향을 미치는 주요 인자임을 확인할 수 있었다. 개발된 감광성 Ag 페이스트를 저온동시소성용 그린 시트에 전면 인쇄한 후 건조, 노광, 현상, 적층, 소성 과정을 통하여, 소성 후 20$\mu\textrm{m}$ 이하의 선폭을 가지는 후막 미세라인을 형성할 수 있었다.

• 한국레이저가공학회:학술대회논문집
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• 한국레이저가공학회 1998년도 추계학술발표대회 초록개요집
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• pp.0-0
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• 1998

-Part I- As market needs become more various, the production of smaller quantities of a wider variety of products becomes increasingly important. In addition, in order to meet demands for more efficient production, long-term unmanned factory operation is prevailing at a remarkable pace. Within this context, laser machines are gaining increasing popularity for use in applications such as cutting and welding metallic and ceramic materials. FANUC supplies four models of $CO_2$ laser oscillators with laser power ranging from 1.5㎾ to 6㎾ on an OEM basis to machine tool builders. However, FANUC has been requested to produce laser oscillators that allow more compact and lower-cost laser machines to be built. To meet such demands, FANUC has developed six models of Slab type YAG laser oscillators with output power ranging from 150W to 2㎾. These oscillators are designed mainly fur cutting and welding sheet metals. The oscillator has an exceptionally superior laser beam quality compared to conventional YAG laser oscillators, thus providing significantly improved machining capability. In addition, the laser beam of the oscillator can be efficiently transmitted through quartz optical fibers, enabling laser machines to be simplified and made more compact. This paper introduces the features of FANUC’s developed Slab type YAG laser oscillators and their applications. - Part II - All-solid-state lasers employing laser diodes (LD) as a source of pumping solid-state laser feature high efficiency, compactness, and high reliability. Thus, they are expected to provide a new generation of processing tools in various fields, especially in automobile and aircraft industries where great hopes are being placed on laser welding technology for steel plates and aluminum materials for which a significant growth in demand is expected. Also, in power plants, it is hoped that reliability and safety will be improved by using the laser welding technology. As in the above, the advent of high-power all-solid-state lasers may not only bring a great technological innovation to existing industry, but also create new industry. This is the background for this project, which has set its sights on the development of high-power, all-solid-state lasers with an average output of over 10㎾, an oscillation efficiency of over 20%, and a laser head volume of below 0.05㎥. FANUC Ltd. is responsible for the research and development of slab type lasers, and TOSHIBA Corp. far rod type lasers. By pumping slab type Nd: YAG crystal and by using quasi-continuous wave (QCW) type LD stacks, FANUC has already obtained an average output power of 1.7㎾, an optical conversion efficiency of 42%, and an electro-optical conversion efficiency of 16%. These conversion efficiencies are the best results the world has ever seen in the field of high-power all-solid-state lasers. TOSHIBA Corp. has also obtained an output power of 1.2㎾, an optical conversion efficiency of 30％, and an electro-optical conversion efficiency of 12%, by pumping the rod type Nd: YAG crystal by continuous wave (CW) type LD stacks. The laser power achieved by TOSHIBA Corp. is also a new world record in the field of rod type all-solid-state lasers. This report provides details of the above results and some information on future development plans.

• 조형예술학연구
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• 제6권
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• pp.226-248
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• 2004

The researcher has tried to develop the aesthetic value of the art and the function of metalwork in conjunction with our daily life. especially has been eager to develop the new possibility of metal urns through the investigation of ordinary metalwork. Funeral urns are vessels to fill the ashes of bodies. As the social issues, including problems of restricted land territory and environmental pollution are awakening, many people are much concerned about the use of urns in recent days. Although social concerns about cremation and urns are getting high, most urns in Korea have been made of ceramic and stone. The shape of old urns are pot style with lids, and their color is simple white or jade green. Moreover, old urns are expensive, unpractical, simple, and furthermore, the feature of urns has not preserved the sense of beauty. In this context, we have narrow choices to select urns, and it has been difficult for us to be familiar with the old-style urns. Therefore, the need for developing metal urns are necessary as the increase of public concerns towards cremation is widely spreading. As it is well known, metal is not only regarded as hard, antibacterial, pro-environmental material , but also regarded as good substance for urns. Metal is also suitable for making urns because of metal's characteristics of easy processing, mass production, and cheap price. The researcher has been tried to find the possibility of art of metalwork through the dissemination of metal urns to the public. The researcher has also attempted to represent the characteristics and symbolic implications of contemporary metal urns for ordinary people to adopt metal urns as their 'Rite Haven'.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1999년도 PROCEEDINGS OF 99 INTERNATIONAL CONFERENCE OF THE KACG AND 6TH KOREA·JAPAN EMG SYMPOSIUM (ELECTRONIC MATERIALS GROWTH SYMPOSIUM), HANYANG UNIVERSITY, SEOUL, 06월 09일 JUNE 1999
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• pp.253-269
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• 1999

The development of telecommunication and information technology requires to develop new piezoelectric materials with small size, low impedance, wide pass band width and high thermal stability of frequency. Langasite (La3Ga5SiO14) single crystal has been researched substitute of quartz and LiNbO3 for the applications of SAW filter, BAW filter and resonator. Its single crystal growth has been carried out by Czochralski Method. So, in order to get single crystal with higher quality, in this study, lnagasite (La3Ga5SiO14) single crystal was grown by using Floating Zone (FZ) method and characterized. For the growth of langasite single crystals, the langasite powder was synthesized at 135$0^{\circ}C$ for 5hrs and the feed rod was sintered at 135$0^{\circ}C$ for 5hrs. The growing rate was 1.5mm/h and the rotation speed was 15 rpm for an upper rotation and 13 rpm for a lower rotation. In order to prevent the evaporation of gallium oxide, Ar and O2 gas mixture was flowed. The growth direction was analyzed by Laue back-scattered analysis. The composition of grown crystal was analyzed suing XRD and WDS. The electrical properties of grown crystal at various frequencies and temperature were discussed.