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하정완,김수관,여환호,김운규,강태호,이준길,조경안,정태영,박정열 朝鮮大學校 口腔生物學硏究所 2000 Oral Biology Research (Oral Biol Res) Vol.24 No.1
Dentigerous cyst is one of the most prevalent type of odontogenic cysts and associated with the crown of an unerupted of developing tooth. Dentigerous cyst can be treated either by enucleation or marsupialization. Marsupialization is the treatment of choice not only it can be performed with damage to adjacent structures but also we hope that embedded tooth of dentigerous cyst is erupted naturally. We report clinical evaluation of tooth which is erupting naturally after marsupialization of three dentigerous cysts.
UHF 400 MHz 대역 20 W급 전력증폭기를 이용한 협대역 아날로그 전치왜곡 선형화 기법
하정완,김강산,김효종 한국항행학회 2019 韓國航行學會論文誌 Vol.23 No.2
In this paper, we have studied narrow-band analog pre-distortion linearization technique using UHF 400 MHz band 20 W power amplifier. The analog pre-distorter used the SC1894 radio frequency power amplifier linearizer(RFPAL) provided by MAXIM Corp and through the look-up table technique confirmed the intermodulation distortion(IMD) performance and the adjusted channel leakage ratio(ACLR) improvement for bandwidth below 1 MHz which does not operate on existing chips. In the 400 MHz (400 ~ 500 MHz) band, IMD performance and the ACLR improvement of up to 17.46 dB based on 1-channel offset and up to 16.6 dB based on 2-channel offset were confirmed. In the system requiring the same linearity, we confirmed power efficiency improvement of 12.41% at output power of over 40 W. 본 논문에서는 UHF 400 MHz 대역 20 W급 전력증폭기를 이용하여 협대역 아날로그 전치왜곡 선형화 기법에 관한 연구를 하였다. 아날로그 전치왜곡기로는 MAXIM社에서 제공하는 SC1894 전력증폭 선형화기를 사용하였으며, look-up 테이블 기법을 통해 기존 칩에서 동작하지 않는 1 MHz 이하의 대역폭에 대한 혼변조 신호 특성 및 인접채널전력 개선을 확인 하였다. 400 MHz (400 ~ 500 MHz)대역에서 1 채널 오프셋 기준 최대 17.46 dB, 2 채널 오프셋 기준 최대 16.6 dB의 혼변조 신호 특성 및 인접채널전력 개선을 확인하였다. 같은 선형성을 요구하는 시스템에 있어 40 W 이상 출력전력에서 12.41% 의 전력효율 개선을 확인하였다.
하정완,김수관,조세인,이철우,정태영,김수흥,김영균 대한악안면성형재건외과학회 2001 Maxillofacial Plastic Reconstructive Surgery Vol.23 No.5
Platelet-rich plasma is an autologous source of platelet-derived growth factor and transforming growth factor beta that is obtained by sequestering and concentrating platelets by gradient density centrifugation. We have used platelet-rich plasma for bone graft, especially allobone graft, at implant surgery, sinus lift procedure, and cyst enucleation. This article is retrospective study from October 1999 to November 2000. All cases were good healing and clinical success.