http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
액상 및 고상 박리방지제가 아스팔트 바인더의 노화에 미치는 영향
정구봉,김기병,이상섭,김우성 한국도로학회 2020 한국도로학회논문집 Vol.22 No.2
PURPOSES : The use of hydrated lime or other liquid anti-stripping agents (ASA) is the most common method of improving the moisture susceptibility of asphalt mixes. ASAs are also known to have an anti-aging effect, according to several researchers. Therefore, the use of ASAs is expected to enhance the stability of asphalt pavements. The purpose of this study is to investigate the anti-aging effect of ASAs that are found in the domestic market. METHODS : In this study, an asphalt binder and a mixture mixed with typical domestic solid and liquid ASAs were prepared and aged to evaluate the physicochemical changes. A liquid additive developed by a Korean oil refinery was used as the liquid ASA, and hydrated lime was utilized as the solid ASA. The aging process of the asphalt was determined in the laboratroy based on previous studies to simulate the aging process inh te field. RESULTS : The result of the laboratory experiment indicates that both the solid and liquid ASAs have an anti-aging effect. Moreover, the liquid additive performed relatively better than the hydrated lime. CONCLUSIONS : If ASAs have an anti-aging effect in addition to the anti-stripping function, it is expected to improve the stability of the asphalt pavement significantly. However, few studies have been carried out on the anti-aging effect of ASAs found in the domestic market. In this study, we conducted a fundamental study on the anti-aging effect to help in the selection and use of ASAs in the domestic asphalt-paving industry.
정구봉 한국로봇학회 2009 로봇학회 논문지 Vol.4 No.1
This work deals with an intuitive method for a planar biped to walk, which is named Relative Trajectory Control (RTC) method. A key feature of the proposed RTC method is that feet of the robot are controlled to track a given trajectory, which is specially designed relative to the base body of the robot. The trajectory of feet is presumed from analysis of the walking motion of a human being. A simple method to maintain a stable posture while the robot is walking is also introduced in RTC method. In this work, the biped is modeled as a free-floating robot, of which dynamic model is obtained in the Cartesian space. Using the obtained dynamic model, the robot is controlled by a model-based feedback control scheme. The author shows a preliminary experimental result to verify that the biped robot with RTC method can walk on the even or uneven surfaces.
정구봉(Goo Bong Chung),이수강(Soo Gang Lee),김성민(Sungmin Kim),오세민(Se Min Oh),이병주(Byung-Ju Yi),김영수(Young Soo Kim),박종일(Jong Il Park),오성훈(Seong Hoon Oh),김희국(Whee Kuk Kim) 한국정밀공학회 2005 한국정밀공학회 학술발표대회 논문집 Vol.2005 No.10월
The goal of this work is to develop and test a robot-assisted surgery system for spinal fusion. The system is composed of a robot, a surgical planning system, and a navigation system. It plays the role of assisting surgeons for inserting a pedicle screw in the spinal fusion procedure. Compared to conventional methods for spinal fusion, the proposed surgical procedure ensures minimum invasion and better accuracy by using robot and image information. The robot plays the role of positioning and guiding needles, drills, and other surgical instruments or conducts automatic boring and screwing. Pre-operative CT images and intra-operative fluoroscopic images are integrated to provide the surgeon with information for surgical planning. Several experiments employing the developed robotic surgery system are conducted. The experimental results confirmed that the system is not only able to guide the surgical tools by accurately pointing and orienting the specified location, but also successfully compensate the movement of the patient due to his/her respiration.
正常및 異常分娩中 母體와 臍帶血漿의 β-endorphin 및 ACTH値의 變動에 關한 硏究
鄭求烈,李揆玩,李珉載,洪性鳳 고려대학교 의과대학 1987 고려대 의대 잡지 Vol.24 No.1
β-endorphin and adrenocorticotrophic hormone (ACTH) are derived from the same precursor protein and they have been implicated as the modulators of pain during the labor process. To investigate their possible role during labor this study was undertaken to determine the levels of β-endorphin and ACTH during labor and delivery in healthy term pregnant women and their neonates after delivery. β-endorphin and ACTH were measured by radioimmunoassay in 22 spontaneous labors, 14 elective cesarean sections and 7 emergency cesarean sections during early and late labor, and after delivery. The results obtained are as follows: 1. In cases of spontaneous vaginal delivery and emergency cesarean section, maternal plasma β-endorphin and ACTH levels were significantly increased during late labor and remained and continuously elevated during the first postpartum hour. 2. In cases of elective cesarean sections, maternal mean plasma levels of β-endorphin and ACTH were significantly lower than levels in spontaneous vaginal deliveries and emergency cesarean sections. 3. There was a significant correlation between meternal plasma β-endorphin and ACTH levels during labor. 4. Umbilical arterial β-endorphin levels in newborn infants after spontaneous vaginal delivery and emergency cesarean section were significantly higher than levels in infants born by elective cesarean section, but only spontaneous vaginal deliveries showed higher umbilical arterial ACTH levels in newborn infants than infants born by elective cesarean section. 5. There was no relationship between meternal and umbilical cord plasma β-endorphin and ACTH. There was not significant correlation between umblical cord plasma β-endorphin and ACTH levels, and fetal weight and placental weight. 6. There was no correlation betwen umbilical arterial pH and Apgar score by mode of delivery, but statistical significance was found to exist in the umbilical arterial pH of emergency cesarean sections and elective cesarean sections. Present studies suggest that β-endorphin and ACTH are significantly increased during late labor due to stress and pain, and hypoxia may be important physiologic stiumuli controlling the release of β-endorphin and ACTH in the human fetus.