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구혈대가 호기말 이산화탄소 분압과 동맥혈 가스분압에 미치는 영향
이장원,김순임,옥시영,김성열 대한마취과학회 1991 Korean Journal of Anesthesiology Vol.24 No.1
The tourniquet is not only used for facilitation of microaurgery by the bloodless surgical field on the extremities but prepared for the intravenous regional anesthesia and isolation arm test estimated the degree of the neuromuscular transmission in the anesthetic field. On the contrary, there are various complications, such as nerve paralysis and tissue damage from compression, and metabolic and hemodynamic changes from ischemia after application of the tourniquet. Since a sudden increase in PaCO₂ immediately following tourniquet deflation is one of the important factors in the hemodynamic changes, we have observed the ehanges of PaCO₂ and PCO₂, after release of the tourniquet on the upper and the lower extremity under the general anesthesia with enflurane, N2O and respiratory control maintaining PaCO₂ level (35 mmHg). The results obtained were as follows; PETCO₂, PaCO₂ and HCO₂- were significantly elevated to peak level within 1 minutue after tourniquet release on the upper and the lawer extremity, except HCO₂ on the upper extremity, and there were more severe changes on the lower extremity. pH and base excess were reduced to significantly lowest level 1 minutue and 5 minutes after tourniquet release respectively, and their changes were more reduction on the lower extremity. There were no statistically significant variations in PaO₂ on the extremities. In the relationship between tourniquet time and P, it was statistically significant linear on the lower extremity (p$lt;0.05) only. Conlusively, since the sudden changes of PaCO₂, pH and base excess after release of tourniquet are closely related with PaCO₂, on time and degree, noninvasive monitoring of PaCO₂ has rapid interpre- tation to change in PaCO₂ after release of tourniquet.
모바일로봇의 정밀 실내주행을 위한 개선된 ORB-SLAM 알고리즘
옥용진,강호선,이장명 한국로봇학회 2020 로봇학회 논문지 Vol.15 No.3
In this paper, we propose a modified ORB-SLAM (Oriented FAST and Rotated BRIEF Simultaneous Localization And Mapping) for precise indoor navigation of a mobile robot. The exact posture and position estimation by the ORB-SLAM is not possible all the times for the indoor navigation of a mobile robot when there are not enough features in the environment. To overcome this shortcoming, additional IMU (Inertial Measurement Unit) and encoder sensors were installed and utilized to calibrate the ORB-SLAM. By fusing the global information acquired by the SLAM and the dynamic local location information of the IMU and the encoder sensors, the mobile robot can be obtained the precise navigation information in the indoor environment with few feature points. The superiority of the modified ORB-SLAM was verified to compared with the conventional algorithm by the real experiments of a mobile robot navigation in a corridor environment.
계면활성제-셀룰로오즈 나노결정(S-CNC)을 이용한 PVA 하이드로 젤의 변형과 특성화
이원종,장미옥,이장재,송동섭,최재영,이승호 한국인그리에학회 2020 한국인그리에학회지 Vol.2 No.2
Polyvinyl alcohol (PVA) hydrogel is attracting widespread attention for its biocompatibility, sterilization, and transparency, which are vital properties when it is used as material for articular cartilage or contact lenses. However, the inherent shortcomings of PVA hydrogel, such as poor thermal stability and mechanical properties limit its application. In this study, PVA hydrogel was reinforced with cellulose nanocrystal (CNC) coated by a surfactant (e.g., Span 60 and Tween 20). And then characterized their properties by DSL, TGA, FT-IR, and swelling ratio. We confirmed the surfactant-coating on CNC was successfully carried out from FT-IR, and PVA hydrogel was increased thermal degradation temperature from 330 oC to 351 oC with increasing S-CNC concentration. In addition, the swelling ratio of PVA hydrogel was decreased dramatically from 640% to 50% with increasing S-CNC concentration.
소량의 Hydrocortisone 이 Vecuronium 에 의한 근이완 회복에 미치는 효과
이정석,김성열,김유재,옥시영,이장원,차영덕 대한마취과학회 1992 Korean Journal of Anesthesiology Vol.25 No.4
Several investigators have described an interaction between muscle relaxants and hydrocortisones which have showed different results. The exact mechanism of this action is not clear and there conflicting results have further confusion. The experimental methods were two ways. In the one of method, a group that vecuronium 0.1 mg/kg was given intravenously is control and a group that hydrocortisones of various doses(0.3, 0.5 and 1 mg/kg) were administered into vein when T_1 was appeared is compared. In the another of method, a control group was anticholinesterase(pyridostigmine 0.12 mg/kg, robinul 0.004 mg/kg) were given at the time when T_1 reached 25% and a group treated with hydrocortisone 0.5 mg/kg when T_1 was appeared is compared. Neuromuscular blockade was measured by recording the twitch response following ulnar nerve stimulation by EMG(ABM, Datex Co. 2Hz 30mA supramaximal voltage). The recovery time from 25% to 75% recovery of twitch height was measured according to recovery index(RI). The results obtained were as follows; 1) The RI of control group treated with vecuronium 0.1 mg/kg alone was 40.32±20.24 minutes and the group which hydrocortisone 0.5 mg/kg was combined, was shorten to 18.79±5.17 minutes, but in the group combined with hydrocortisone 1.0 mg/kg and 0.3 mg/kg, the RI was also tended to short, but not significant. 2) In the RI of vecuronium 0.1 mg/kg, anticholinesterases were given, was 8.46±5.06 minutes and the group combined with hydrocortisone 0.5 mg/kg was shorten to 4.77±1.82 minutes significantly. Conclusively, in the small doses of hydrocortisone, there is a effect of antagonism to the vecuronium induced blockade and a potentiated effect to the anticholinesterase activity to the vecuronium.
CNN 기반 주행 중인 차량 간 상대속도 추정 알고리즘
강호선(Ho-sun Kang),옥용진(Yong-jin Ock),이장명(Jang-Myung Lee) 제어로봇시스템학회 2021 제어·로봇·시스템학회 논문지 Vol.27 No.1
In this paper, we proposed an estimation algorithm of the relative velocity between two driving vehicles based on CNN(Convolutional Neural Network), as the perception of the surrounding environment around an autonomous car, such as distance and speed of other vehicles, is important. The proposed algorithm estimated the velocity of a target vehicle by using a stereo camera without any other sensors. A stereo camera is a sensor that acquires simultaneously RGB images and depth maps, and it is widely used for autonomous vehicles to obtain various information. The developed CNN-based semantic segmentation model with high speed and accuracy was used to recognize the target vehicle, detecting the shape of the target object and omitting background information around it. Due to this effect, the distance between the autonomous vehicle and target vehicle is more accurately estimated. The relative speed between each vehicle was estimated using the distance and time difference between frames. The performance of the proposed algorithm was compared with conventional methods and it was confirmed that the speed of the target vehicle was more accurately estimated using only the stereo camera.