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외상 환자의 하대정맥 대 하행 대동맥 직경 비의 유용성
손강호,김미란,김양원,윤유상 대한응급의학회 2010 大韓應急醫學會誌 Vol.21 No.1
Purpose: An accurate assessment of body fluid status is a significant challenge during every clinical examination. In many disorders, the therapy and its effectiveness depend on appropriate evaluation of body fluid state, especially in the trauma patient. The purpose of this study was to evaluate the clinical significance of the IVC/aorta diameter index on abdominal CT scans and to determine whether? The IVC/aorta diameter index was useful for predicting the outcome of trauma patients in the emergency department. Methods: This study was a retrospective analysis of data acquired between December 2008 and April 2009. We included 108 trauma patients who received abdominal CT in the emergency department. Persons who had a major medical problem such as liver cirrhosis, or who were transferred from other hospitals for ICU care, or who were younger than 15 years, were excluded. IVC and aorta were measured below the infrarenal vein in the abdominal CT in an axial view. Clinical assessment included the patient’s final diagnosis, blood pressure, heart rate, weight and whether he was dead or not. Receiver operating characteristic (ROC) curves were used to find the value of the IVC/aorta diameter index that maximized the sum of the sensitivity and specificity. Statistical analysis was performed using SPSS 17.0. Results: We studied 135 patients (trauma 108 and non trauma 27). The mean IVC/aorta diameter index of nontrauma patients was 1.26±0.17; for trauma patients it was 0.80±0.33. The average IVC/aorta index in the shock group at arrival were significantly smaller than in the non shock group (0.57±0.27 versus 0.89±0.3). Conclusion: The inferior vena cava/aorta diameter index in trauma patients is useful in assessment of injury severity and prognosis.
다이오드 직렬 궤환을 이용한 개별 차수 혼변조 발생기 및 응용
손강호(Kang-Ho Son),김승환(Seung-Hwan Kim),김일규(Ell-Kou Kim),김영(Young Kim),윤영철(Young-Chul Yoon) 한국전자파학회 2008 한국전자파학회논문지 Vol.19 No.10
본 논문에서는 개별 차수 혼변조 신호 발생기를 이용한 전치 왜곡 선형화기 구조를 제안하였다. 혼변조 신호발생기는 공통 에미터 증폭기의 에미터 단자에 쇼트키 다이오드를 삽입하여, 3차와 5차 혼변조 신호를 다이오드바이어스 전압에 따라서 발생시킨다. 이렇게 만들어진 혼변조 신호는 다이오드의 직렬 궤환을 이용한 것으로, 다이오드 바이어스 제어에 따라서 혼변조 신호의 크기와 위상을 변화시킬 수 있다. 이러한 혼변조 발생기를 전치 왜곡 선형화기로 사용했을 때, 반송파 2톤 신호 인가 시 3차와 5차 혼변조 신호는 각각 13.5 ㏈, 0.9 ㏈의 개선을 보였고, 광 대역폭을 갖는 CDMA IS-95 2FA 신호를 인가하였을 경우, 중심 주파수로부터 ±0.885 ㎒, ±1.23 ㎒ 떨어진 지점에서 ACLR이 각각 2.3 ㏈, 2.5 ㏈의 개선됨을 확인하였다. This paper proposes an individual order predistortion linearizer using intermodulation distortion(IMD) generator for cancellation the third and the fifth IMD of power amplifier. The IMD generator for controlling the third and the fifth IMD consist of common Emitter amplifier and Schottky diode. These signals are generated by series feedback of Schottky diode to obtain the inverse AM/AM and AM/PM characteristics of power amplifier. The individual order predistorters are consisted of individual IMD generator, power splitter and combiner. The test results show that the third and the fifth IMD can be improved by a maximum 13.5 ㏈ and 0.9 ㏈ in case of CW 2-tone signals. Also, the Adjacent Channel Leakage Ratio(ACLR) can be improved 2.3 ㏈, 2.5 ㏈ at ±0.885 ㎒, ±1.23 ㎒ offset frequency for CDMA IS-95 2FA signals.