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Diplexer 구조를 이용한 Dual Band 방향성 커플러
김기중,박자영,정영학,배효근,김남흥,김학선,Kim Ki-Joong,Park Ja-Young,Jeong Young-Hak,Bae Hyo-Gun,Kim Nam-Heung,Kim Hak-Sun 한국전자파학회 2005 한국전자파학회논문지 Vol.16 No.8
본 논문은 glass 기판 위에 RE IPD(Integrated Passive Device) 기술을 이용하여 dual band 방향성 커플러의 새로운 설계와 구현을 하였으며, 이러한 구조는 전력 증폭기의 출력부에 closed loop 전력 제 어용 GSM/GPRS cellular phones에 적용할 수 있다. 커플러는 방향성 향상을 위하여 보상 capacitor를 이용하였으며, 상호 밴드의 간섭을 최소화하기 위하여 새로운 방법의 필터링 구조(diplexer)를 갖는 커플러를 구현하였다. In this paper, a novel design and implementation of a dual-band directional coupler based on RF IPD(Integrated Passive Device)-on-glass technology is proposed, which can be adopted in GSM/GPRS cellular phones for closed loop power control at the output of the power amplifier. The proposed coupler has a compensation capacitor to improve the directivity, and was designed using a new diplexing structure to minimize the cross-band isolation.
스텐레스강 평직망에 담지된 Pt/Al<sub>2</sub>O<sub>3</sub>촉매 제조 및 그의 에틸렌 산화활성
김기중 ( Ki-joong Kim ),안호근 ( Ho-geun Ahn ) 한국환경기술학회 2011 한국환경기술학회지 Vol.12 No.3
본 연구에서는 질산 알루미늄(Al(NO<sub>3</sub>)<sub>3</sub>)과 염화 백금산(H<sub>2</sub>PtCl<sub>6</sub>)을 전구체로 이용하여 스텐레스강 평직망(SSWC)에 담지된 Pt/Al<sub>2</sub>O<sub>3</sub>촉매를 제조하였다. SSWC에 대한 Al<sub>2</sub>O<sub>3</sub>의 부착력을 향상시키기 위하여 바인더를 첨가하거나 표면 산화법(산 또는 고온)을 이용하였으며, 활성금속으로서 백금을 Al<sub>2</sub>O<sub>3</sub>/SSWC에 담지 하였다. 질소가스 흡착, X-선 회절분석기, 주사전자 현미경, 투과전자 현미경, 그리고 Al<sub>2</sub>O<sub>3</sub>의 부착력을 통하여 물리적 특성을 분석하고, 상압 유통식 고정층 반응기를 이용하여 에틸렌에 대한 산화 활성을 조사하였다. 결과적으로, 습식 및 고온 산화법을 이용하여 SSWC를 전처리하면 표면의 거칠기가 증가하여 SSWC보다 Al<sub>2</sub>O<sub>3</sub> 부착력이 향상되었다. 고온 산화법을 이용하여 SSWC를 열처리할 때 온도가 증가할수록, 열처리 시간이 길수록 표면의 거칠어지는 정도는 증가하였으며, 최적의 Al<sub>2</sub>O<sub>3</sub>부착력은 800℃에서 12시간 동안 열처리할 때로 나타났다. Al<sub>2</sub>O<sub>3</sub>/SSWC800에서 백금의 담지특성은 Al<sub>2</sub>O<sub>3</sub>의 부착량(또는 부착력)에 크게 의존하였다. Al<sub>2</sub>O<sub>3</sub>/SSWC-800에 백금을 담지할 때 백금 전구체의 농도가 증가할수록 에틸렌의 완전산화가 저온에서 일어났으며, 최적의 담지량은 코팅된 Al<sub>2</sub>O<sub>3</sub>에 대하여 약 10wt%이었다. 공간속도가 증가함에 따라 에틸렌 전화율은 감소하였으며, 반응온도가 낮을수록 공간속도의 영향이 커짐을 알 수 있었다. Pt/Al<sub>2</sub>O<sub>3</sub> catalysts supported on stainless steel wire cloth(SSWC) were prepared using aluminum nitrate(Al(NO<sub>3</sub>)<sub>3</sub>) and chloroplatinic acid(H<sub>2</sub>PtCl<sub>6</sub>) as precursors. SSWC was thermally or acid treated to increase the adhesive strength of Al<sub>2</sub>O<sub>3</sub> by improving superficial roughness. SSWC was coated with Al<sub>2</sub>O<sub>3</sub> by an impregnation method using either an Al(NO<sub>3</sub>)<sub>3</sub> solution or a mixed solution containing Al(NO<sub>3</sub>)<sub>3</sub> and a binding agent. After Al<sub>2</sub>O<sub>3</sub> coating, Pt particles as a catalytic component were deposited on the Al<sub>2</sub>O<sub>3</sub>/SSWC. These catalysts were characterized by N2 gas adsorption, X-ray diffraction(XRD), scanning electron microscopy(SEM), transmission electron microscopy(TEM), and adhesive ability of Al<sub>2</sub>O<sub>3</sub> on SSWC. The catalytic activity for ethylene oxidation was investigated using a flow reactor under atmospheric pressure. The apparent roughness of SSWC was markedly increased by thermal oxidation, and adhesive ability of the Al<sub>2</sub>O<sub>3</sub> was enhanced compared to bare SSWC. The optimum Al<sub>2</sub>O<sub>3</sub> adhesion was obtained by thermal oxidation at 800℃ for 12hr(SSWC800). Surface roughness of SSWC was increased with increasing treatment temperature and time. It was also known that the amount of Pt particles deposited on Al<sub>2</sub>O<sub>3</sub>/SSWC800 depended strongly on adhesive ability of Al<sub>2</sub>O<sub>3</sub>(or adhesive amount), and optimum concentration of H<sub>2</sub>PtCl<sub>6</sub> solution for Pt loading was about 10wt% on Al<sub>2</sub>O<sub>3</sub> <sup>2nd</sup>/SSWC800. Catalytic activity for C<sub>2</sub>H<sub>4</sub> was decreased with increasing gas hourly space velocity(GHSV). It was also shown that the GHSV had a great affect on the C<sub>2</sub>H<sub>4</sub> conversion at lower reaction temperature.
김기중(Ki Joong Kim),김동남(Dong Nam Kim),이하백(Ha Baik Lee),문수지(Soo Jee Moon) 대한소아알레르기호흡기학회(구 대한소아알레르기 및 호흡기학회) 1995 소아알레르기 및 호흡기학회지 Vol.5 No.1
N/A A clinical study was performed on 27 newborn infants with pulmonary air leaks, who were admitted to the NICU of Hanyang University Hospital from January 1986 through December 1993.The results were as follows 1) The incidence of air leaks was 0.24% of overall newborn infants in both sexes. 2) Air leak incidence was variable according to the perinatal factors such as age of life (1 day' 81.5Y%), birth weight (normal: 66.7Y%), type of delivery (cesarean section' 57%). Apgal score (<6 at 5 minutes: 55.6%), gestational period (fullterm: 55.4%) and under lung disease (meconium aspiration syndrome' 48.1%). 3) Of the 27 patients of pulmonary air leaks, pneumothorax was most frequently observed in 21 subjects, and pneumomediastinum, pulmonary interstitial emphysema and pneumo- peritoneum were noted in order of frequency. Air leaks we e developed primarily in 10 and secondarily in 1 1 of the 21 patients with pneumothorax, respectively, which were found especially at the right thorax. 4) Clinical symptoms and signs were decreased breathing sound, tachypnea, cyanosis, chest retraction, apnea, lethargy and bradycardia in order of frequency. 5) With simple oxygen therapy, 8 patients were completely improved. However, out of the 18 patients who had underwater seal drainage, 10 patients were expired. In conclusion, early diagnosis and proper management for pulmonary air leaks of the newborn infants are absolutely needed.