http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
심지연,김경미,정경운,최인철,박희선,심지연 대한마취통증의학회 2014 Korean Journal of Anesthesiology Vol.66 No.4
Percutaneous trans-catheter aortic valve implantation (TAVI) is recommended for inoperable patients with severe aortic stenosis at high risk for conventional aortic valve replacement. Originally, TAVI was mostly performed under general anesthesia. Here we describe two cases of transfemoral TAVI performed under monitored anesthesia care (MAC) with dexmedetomidine. Dexmedetomidine provides sedation, analgesia with minimal respiratory depression. Although MAC during transfemoral TAVI has limitations, such as unexpected patient movement and difficulty in intra-procedural use of transesophageal echocardiography, MAC with dexmedetomidine is feasible with close monitoring, fluoroscopic guidance and the participation of experienced anesthesiologists.
심지연,안원식 대한마취통증의학회 2007 Korean Journal of Anesthesiology Vol.52 No.5
심전도나 이산화탄소 파형은 상대적으로 많은 정보를 임상가에게 주고 있다. 반면, 시간에 따른 변화를 압축하여 단순히 상수값을 사용하는 동맥압이나 맥박산소포화도는 상대적으로 적은 정보를 임상가들에게 제공한다. 그러므로, 이러한 파형에 대한 연구를 활성화하여 이들을 임상에 이용한다면 보다 정확하게 환자의 상태를 파악할 수 있어 양질의 진료를 수행하는 데 도움을 줄 수 있을 것으로 생각된다.저자: 심지연·안원식*울산대학교 의과대학 서울아산병원 마취통증의학교실,*서울대학교 의과대학 서울대학교병원 마취통증의학과서울시 종로구 연건동 28, 우편번호: 110-744E-mail: aws@snu.ac.kr
Characteristics of Al/steel magnetic pulse tubular joint according to discharging time
심지연,강봉용,김일수 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.8
The MPW (Magnetic pulse welding) process is governed by the electromagnetic force that results from electromagnetic interaction produced by a coil. To produce high electromagnetic force, the MPW process needs to charge high electrical energy through capacitors. The total capacitance and system inductance has an effect on the discharge time, and discharge time also has an effect on the joint. Therefore, the objective of this research is to analyze the effect of the discharge time on the joint and to quantify it using the FE-model. To achieve this, MPW has been performed using Al1070tube and S45Crod. After the experiment, the interfaces of the joint with variations of discharge time were observed utilizing a scanning electron microscope. In addition, a two dimensional electromagnetic-mechanical coupled FE-model has been developed for quantification. Experimental results demonstrated the impact of welded interfaces that have various lengths and amplitudes. It was confirmed from the numerical works that the creation of a wavy form is derived from the change of electromagnetic force according to the variation of discharge time. As the discharge time decreased, the lengths and amplitudes of the wave form decreased through the reduction of the generated electromagnetic force.
Characteristics of 5052 aluminum alloy sheets joint using electromagnetic force
심지연,강봉용,김일수 대한기계학회 2017 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.31 No.7
Recently, trends in lightweight materials and their fabrication process have been focused on reducing global warming and environmental pollution. Therefore, the demand for aluminum is increasing as representative lightweight material. In general, a fusion welding process, such as high-speed GTA (Gas tungsten arc) welding, is used to join aluminum sheet, or for mechanical joining which accomplished using a rivet process. However, it is difficult to ensure a high-quality joint, given that various defects are often reported. Therefore, in this study, we propose not only welding aluminum sheets using a MPW (Magnetic pulse welding) process, but also analyzing characteristics of these joints through experimental and numerical analyses. In order to achieve this objective, a proper coil type was selected after preliminary testing in which a MPW process was performed using 0.5 mm thick A5052 sheets. After the welding, the characteristics on joint were analyzed using a peel test and optical microscope. Although there was an overlapping zone, and the coil shape was quadrangular, a circular joint shape was achieved with no evidence of welding in the center of the joint. These tests confirmed that nonuniform distributions of electromagnetic forces cause the only overlapping zone, located on the adjacent edge of the coil.