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다층 구조를 적용한 Dual band 방향성 결합기 개발에 관한 연구
유명재,유찬세,박성대,이우성,강남기,Yoo Myong Jae,Yoo Joshua,Park Seong Dae,Lee Woo S.,Kang Nam K. 한국마이크로전자및패키징학회 2004 마이크로전자 및 패키징학회지 Vol.11 No.2
전력 결합기 및 전력 배분기는 마이크로파 수동 소자의 일종으로 전력을 결합하거나 나눌 때 쓰이는 것이다. 최근의 정보통신 시스템의 추세를 보아 수동 소자의 집적화 및 소형화가 요구된다. 본 연구에서는 이러한 추세를 감안하여 2012 크기의 다층 구조를 적용한 양대역 방향성 결합기를 저온 동시소성 기술을 활용하여 제작하였다. DCS(Digital communication system)와 EGSM(European global system for mobile) 대역에서 각기 원하는 커플링을 얻기 위해서 수직 결합 패턴들을 다층 구조에 적용하였다. 제작된 방향성 결합기의 결합성, 삽입 손실, 격리성 및 방향성 등의 특성들을 측정하였고 시뮬레이션 결과들과 비교 고찰하였다. A coupler or divider is a microwave passive component used for power coupling or dividing. Regarding the trend of current telecommunication systems monolithic integration of passive components is highly desirable. In this study by the LTCC(Low temperature co-fired ceramics) technology a 2012 size type dual band coupler with multi-layer structure was fabricated. To achieve the desired coupling values for both DCS and EGSM bands, broad side coupled patterns were used with multi-layer structure. Its characteristics such as coupling, insertion loss, isolation and directivity values were measured and compared with simulation results.
유명재,박성대,임호선,이우성,Yoo, Myong-Jae,Park, Seong-Dae,Lim, Ho-Sun,Lee, Woo-Sung 한국마이크로전자및패키징학회 2012 마이크로전자 및 패키징학회지 Vol.19 No.1
Currently due to increasing integration of various electronic devices and need of multi-functions, more and more heat is produced and for electronic devices to achieve maximum performance with optimum life time, heat dissipation is critical. A solution to such problems is use of high heat dissipative insulating sheet. In this paper status of current products are introduced and several technology aspects to meet the demand of increased heat dissipation needs is introduced.
유기 용매 혼합비에 따른 슬러리의 유동 특성과 세라믹 그린 쉬트의 두께 제어
김준영,김승택,박종철,유명재,Kim, Jun-Young,Kim, Seung-Taek,Park, Jong-Chul,Yoo, Myong-Jae 한국전기전자재료학회 2008 전기전자재료학회논문지 Vol.21 No.3
The effect of organic solvent mixture ratio on the rheology property of slurry and thickness control of ceramic green sheet was investigated. For selecting a suitable dispersant multiple light scattering method was used to evaluate the particle migration velocity and variation of clarification layer thickness. Using the selected dispersant the dispersion property of solution according to solvent mixture ratio was investigated. Binder and plasticizers were added to formulate slurries and their viscosity was evaluated according to solvent mixture ratio. Ceramic green sheets with average thickness of 30, 50 urn were fabricated via tape casting and their thickness tolerances measured. As a result according to solvent mixture ratio the solution and slurry properties varied and for the mixture ratio of ethanol/toluene of 80/20 the ceramic green sheet with the lowest thickness tolerance was obtained.
표면 개질된 나노피브릴화 셀룰로오스를 이용한 에멀젼 안정화 및 고분자 입자 제조
김보영 ( Bo-young Kim ),문지연 ( Jiyeon Moon ),유명재 ( Myong Jae Yoo ),김선민 ( Seonmin Kim ),김정아 ( Jeongah Kim ),양현승 ( Hyunseung Yang ) 한국공업화학회 2021 공업화학 Vol.32 No.1
In this work, the surface of hydrophilic cellulose nanofibrils (CNFs) was modified precisely by varying amounts of cetyltrimethylammonium bromide (CTAB) to produce CNF-based particle surfactants. We found that a critical CTAB density was required to generate amphiphilic CTAB-grafted CNF (CNF-CTAB). Compared to pristine CNF, CNF-CTAB was highly efficient at stabilizing oil-in-water Pickering emulsions. To evaluate their effectiveness as particle surfactants, the surface coverage of oil-in-water emulsion droplets was determined by changing the CNF-CTAB concentration in the aqueous phase. Furthermore, styrene-in-water stabilized by CNF-CTAB surfactants was thermally polymerized to produce CNF-stabilized polystyrene (PS) particles, offering a great potential for various applications including pharmaceuticals, cosmetics, and petrochemicals.
셀룰로오스 나노 섬유에 의한 폴리(비닐 알코올) 필름 치수 안정성 향상 연구
이성수(Seong-Soo Lee),김선민(Seon Min Kim),유명재(Myong Jae Yoo),강호종(Ho-Jong Kang) 한국고분자학회 2019 폴리머 Vol.43 No.3
표면이 개질된 셀룰로오스 마이크로/나노 섬유를 폴리(비닐 알코올)(PVA)과 혼합하여 복합필름을 제조하고 이들의 혼합 특성 및 치수 안정성 변화를 살펴보았다. 나노 섬유는 마이크로 섬유에 비하여 PVA와 혼합 특성이 우수하며 두 섬유 모두 표면 개질에 의하여 혼합 특성이 향상됨을 알 수 있었다. 이러한 혼합 특성 개선은 섬유 첨가에 따른 필름 헤이즈 현상을 감소시켜 PVA 필름의 광투과 특성이 우수해 짐을 확인하였다. 아울러 셀룰로오스 섬유 첨가는 PVA 필름의 치수안정성을 향상시키며 표면 개질 방법 및 정도에 따라 섬유 첨가가 필름 결정화도에 영향을 미쳐 이에 따른 치수안정성 변화를 확인할 수 있었다. Poly(vinyl alcohol)(PVA) films with cellulose micro and nano fibers were obtained and their mixing characteristics and dimensional stability were studied. Cellulose nano fiber shows better mixing characteristic with PVA than cellulose micro fiber, resulting in that, PVA film with cellulose nano fiber shows lower haze and higher transmittance. Mixing characteristics and transmittance of both films enhanced by the surface modification of cellulose fibers. In addition, the dimensional stability of PVA films improved by both nano and micro cellulose fibers. The methods and the level of surface modification affect the degree of crystallinity in PVA film and dimensional stability.
스핀 스프레이 방식으로 제조된 바륨계 페라이트 박막의 EMI (Electromagnetic Interference) 차폐 특성
오혜령 ( Hye Ryeong Oh ),박연주 ( Yeon-ju Park ),이우성 ( Woo-sung Lee ),유찬세 ( Chan-sei Yoo ),유명재 ( Myong-jae Yoo ),서인태 ( Intae Seo ) 한국전기전자재료학회 2024 전기전자재료학회논문지 Vol.37 No.2
The low-temperature deposition of BaNi<sub>(2-x)</sub>Co<sub>x</sub>Fe<sub>16</sub>O<sub>27</sub> thin films with a Ba hexaferrite structure for electromagnetic shielding was studied. The BaNi<sub>(2-x)</sub>Co<sub>x</sub>Fe<sub>16</sub>O<sub>27</sub> thin films produced through the spin spray process were suitable for thin film deposition on a flexible substrate because it crystallized well at low temperature below 90℃. The change in shielding characteristics depending on the Co content of the BaNi<sub>(2-x)</sub>Co<sub>x</sub>Fe<sub>16</sub>O<sub>27</sub> thin film was investigated, and excellent shielding characteristics with S21 of -1 dB were obtained in a wide frequency range of 26~40 GHz when the Co content was 0.4 or more. The purpose of this study is to analyze changes in shielding properties caused by change in Co content in relation to phase changes in BaNi<sub>(2-x)</sub>Co<sub>x</sub>Fe<sub>16</sub>O<sub>27</sub> and obtain basic data for developing excellent flexible electromagnetic wave shielding materials.
광개시제 종류 및 함량에 따른 광경화형 잉크의 광경화 특성과 인쇄회로기판용 에칭 레지스트 소재로의 적용성 연구
김보영 ( Bo-young Kim ),조수빈 ( Subin Jo ),정과정 ( Gwajeong Jeong ),박성대 ( Seong Dae Park ),김지훈 ( Jihoon Kim ),최의근 ( Eui-keun Choi ),유명재 ( Myong Jae Yoo ),양현승 ( Hyunseung Yang ) 한국공업화학회 2023 공업화학 Vol.34 No.4
전자 기기의 소형화, 집적화 및 박형화에 따라 인쇄회로기판 제조 시 미세한 회로 패턴이 요구되고 있다. 기존의 인쇄회로기판은 dry film resist를 이용한 photolithography 법을 적용하여 주로 제조하지만, 미세 회로 패턴 구현을 위해서는 정밀한 마스크 설계 및 고가의 노광장비 등이 필요하다는 한계점이 있다. 이에 따라서 최근에는 dry film resist를 대체하여 미세 회로 패턴 형성에 유리한 광경화형 잉크를 직접인쇄 공정을 통해 인쇄회로기판의 회로 패턴을 형성하는 연구들이 관심받고 있다. 광경화형 잉크를 통한 회로 패턴 형성을 위해서는 동박과의 밀착성, 패턴 형성 과정에서의 에칭 저항성, 박리 특성의 제어가 필수적이다. 본 연구에서는 광개시제 종류 및 함량이 다른 여러 광경화형 잉크를 제조하고 이들의 광경화 거동을 분석하였다. 또한, 광경화형 에칭 레지스트 잉크로의 적용성 평가를 위해 에칭 저항성, 박리성, 밀착성 등을 분석하였다. As electronic devices become smaller and more integrated, the demand for manufacturing thin, flexible printed circuit boards (FPCBs) has increased. Although FPCBs are conventionally manufactured by a photolithography method using dry film resist, this process is complicated, and the mask is specifically designed to obtain the precision of the desired circuit line width. In this regard, manufacturing FPCBs with fine patterns through the direct printing method of photocurable inks has gained growing attention. Since the manufacturing process of FPCBs is based on the direct printing method that includes etching and stripping processes utilizing acid and basic chemicals, controlling the adhesion strength, the etching resistance, and the strippability of photocured inks has drawn a lot of attention for the fabrication of fine patterns through photocurable inks. In this study, acrylic ink with various types and contents of the photoinitiator was prepared, and the curing behavior was analyzed. Also, the adhesion strength, etching resistance, and strippability were analyzed to evaluate the applicability of developed photocurable etching resist inks.