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SimulationX를 이용한 Remote Control Valve의 특성 분석에 관한 연구
정유성(Yoo Seong Jeong),정원지(Won Jee Chung),이산성(San Sung Lee),이정민(Jung Min Lee),최경신(Kyoung Shin Choi) 한국기계가공학회 2017 한국기계가공학회지 Vol.16 No.5
Compared to other types of power, hydraulic energy is the most commonly used for heavy vehicles and ships because it has fewer location and space constraints, and its controllability can be maintained even under adverse conditions. Operators have controlled a main control valve of ship winches by pushing or pulling the lever, which is directly connected to the spool. However, because of the spatial arrangement, the importance of remote control valves has emerged. In this paper, experiments of the hysteresis characteristics were performed by analyzing the remote-control valve using a valve tester and RA2300. The validity was verified by comparing with the analytical model using SimulationX as the hydraulic analysis program. This study examined the effects of the spool"s notch (Non, End-mill, and Spherical) and the effects of stiffness and pre-load of the spool spring on Spool stroke, open area, and hysteresis characteristics. It is considered possible to reduce the cost and the, trial and error process in designing remote-control valves in the future.
제왕절개술의 전신마취 유도 시 투여한 Alfentanil이 산모와 태아에 미치는 효과
김준영,정유성,연준흠,김계민,이윤석,홍기혁,김경태 대한마취과학회 2002 Korean Journal of Anesthesiology Vol.43 No.5
Background: During general anesthesia for a cesarean section, light depth of anesthesia frequently leads to matemal awareness and pain responses. The aim of this study was to evaluate the effects of alfentanil on the mother and neonate during a cesarean section. Methods: Forty four parturients undergoing general anesthesia for an elective cesarean section were enrolled in this study. General anesthesia was induced with propofol 2 mg/kg and succinylcholine 1.5 mg/kg after an intrvenous injection of normal saline 0.02 ml/kg for the control group of alfentanil 10㎍/kg for the alfentanil group. After tracheal intubation, anesthesia was maintained with O_2 (2 L/min)-N_2O (2 L/min)-isoflurane (0.5% end tidal). Mean blood pressure (MBP), heart rate, bispectral index (BIS) and maternal pain responses by an isolated forearm technique were measured every 1 min until delivery. Apgar scores of neonates were measured at 1 min and 5 min after delivery. Results: There were no differences between groups in the MBP, BIS or maternal pain responses. However heart rates were lower in the alfentanil group than in the control group (P = 0.017). Conclusions: The supplemental administration of alfentanil 10㎍/kg can attenuate the changes in matemal heart rate during general anesthesia for a cesarean section without neonatal Apgar score decline. (Korean J Anesthesiol 2002; 43: 619~624)