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전기 이륜차 정밀 주행가능거리 시뮬레이션을 위한 차량 드래그 및 타이어 슬립 적용 연구
백남철(Nam-Chul.Paik) 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.11
The proliferation of electric two-wheelers represents a significant trend in modern urban transportation, emphasizing sustainability. These alternative modes of transport, replacing conventional fuels, are recognized as environmentally friendly and energy-efficient options. A pivotal challenge for electric two-wheelers is providing adequate driving range. However, conventional driving range tests are characterized by substantial time and cost consumption. Conducting tests under various conditions compounds inefficiencies. This study aims to implement a simulation model for cost-effective driving range tests across diverse conditions. To achieve this, the study measures and models the efficiency of key drivetrain components—the motor and motor control unit (MCU)—across various operational points. Furthermore, the study addresses factors affecting electric two-wheeler drivetrains after motor output, such as chain, belt, gear, and weight resistance, by precise modeling of drag. Accurate modeling of tire slip proportionate to dynamic torque during operation is crucial. Such modeling enhances accuracy in various tests, including driving modes, maximum acceleration, and peak slope conditions. Incorporating tire slip modeling, this research finely simulates its influence on total travel distance. The study’s results demonstrate an approximate 3% difference between simulation and empirical measurements in two driving modes, CVS40 and WMTC. Additionally, applying the simulation model to tests on maximum slope capabilities, 0-50 kph acceleration, and top speed attests to a 3% accuracy level. This precise simulation model establishes a foundation for developing control logic and validating fault diagnostics. As a result, it holds promise for accurate predictions of electric two-wheeler driving range and supports endeavors toward performance enhancement.
Numerical optimization of an axial propeller runner for small-hydro power application
백남철(Nam-Chul Paik),변순석(Sun-Seok Byeon),김윤제(Youn-Jea Kim) 대한기계학회 2010 대한기계학회 춘추학술대회 Vol.2010 No.11
The aim of the paper is to optimize the axial propeller turbine operating with a gross head of 3~6 m and flow rate of 10 ㎥/s. Three stages of optimization are executed for the turbine with the geometrical modifications by varying the number of runner blade, pitch angle and 3 different shapes of blade profiles. This study has attempted to acquire basic design data, viz., the output power, efficiency and pressure distribution to suggest the sound method of optimization. 3~5 blade, 25°~40° of pitch angle and NACA4306 and NACA4312, pump-based, thin foil blade profiles are examined to acquire the characteristics of performance. This study is executed through a commercial finite element analysis (FEA) package, ANSYS, and CFX. The results reveal the flow characteristics and suggest an optimizing method for axial propeller turbine.
고무 제품(製品)의 노화성(老化性)에 관(關)한 연구(硏究)(제1보(第1報))
허동섭,백남철,Huh, Dong-Sub,Paik, Nam-Chul 韓國고무學會 1966 엘라스토머 및 콤포지트 Vol. No.
The aging characteristics of vulcanized rubber products manufactured in Korean industries have been studied, especially in terms of relationship between aging temperature and time, and also the comparison of results between Geer's oven testing and tube testing was made. It was assessed from changes in tensile properties resulting from conditioning at elevated temperatures for specified period of time. Even though the recipe of each sample is different, the results, as would be expected, has shown that at lower aging temperature the change of tensile strength indicate moderately and at the elovated severely as shown in Figure 9. Consequently, in spite of that the results from conditioning at various temperatures for certain specified period of time must be equivalent to each other, it shows inignorable tolerance. The results of Geer's oven test and tube test have shown slightly different value. It seemed to be caused by the result of migration phenomena on aging in Geer's oven.
정영복,강기서,백남철 ( Young Bok Jung,Ki Seo Kang,Nam Chul paik ) 대한슬관절학회 1992 대한슬관절학회지 Vol.4 No.1
Arthroscopy is a procedure for diagnosing and treating acute and chronic internal derangements of the knee joint, now its roles are more widening because of its advantage high accuracy of diagnosis, shortening of the recovery time. Especially introduc- tion of arthroscopic operation under the local anesthesia was possible to decrease side effects and complication by general anesthesia. We have experienced 369 cases of the intra-articular problems of the knee joint who were treated by arthroscopic operation from April 1989 to May 1991. Among them 165 cases which were treated by arthroscopic operation under local anesthesia were reviewed retrospectively. The results are as follows: 1. The patients ranged in age from 12 years to 83 years and 54 (33 %) patients were in third decade, 110 patients were men and male was affected 2 times more than female. 2. Time from injection of the local anesthetic to start of operation was average 38.6 minutes and consuming time during operatin was average 64.4 minutes. 3. The most common arthroscopic finding was meniscal lesions in 73 cases (me- dial 28, latera1 45), the next was osteoarthritis in 52 cases, and the third was ligament injury in 33 cases. 4. Under the local anesthesia the most common arthroscopic operation was partial meniscectomy in 58 cases, the next was synovectomy in 22 cases and the third was plica removal in 13 cases. 5. Arthroscopic operation was performed 104 cases in only local anesthetics-bupi- vacaine 100 mg + lidocaine 400 mg but for sedation during operation injected deme- rol and/or valium in 61 cases (37 %), 6. The side effect of local anesthesia during intra or postoperative period were temporal hypotension and bradycardia in 3 cases but recovered soon without sequehe. In conclusion, arthroscopy under the local anesthesia is considered a simple, safe, reliable procedure for patients in whom clinical examination suggests intra-articular disorders of the knee.
키토산-교원질 해면체를 이용한 가토 슬관절 골연골 결손의 치료
강기서(Ki Ser Kang),장의찬(Eui Chan Jang),송광섭(Kwang Sup Song),백남철(Nam Chul Paik),김미경(Mi Kyung Kim),손태일(Tae Il Son) 대한정형외과학회 2006 대한정형외과학회지 Vol.41 No.1
목적: 실험실에서 제작된 키토산-교원질 해면체에 이식된 가토의 연골 세포의 생착 가능성과 이 해면체가 동물 실험을 통한 관절 연골 결손에 대한 지지체로서 적합성 및 유용성을 알아보고자 하였다. 대상 및 방법: 실험실 하에 키토산-교원질, 키토산 해면체에 연골 세포를 배양한 후 염색 소견(H&E, MTT stain)으로 배양 결과를 평가하였으며 동물 실험에서 20마리의 토끼 슬관절에 지름 5 ㎜의 완전 연골 결손을 만든 후, 좌측 슬관절에 키토산-교원질 해면체를 실험군, 우측에는 그대로 두어 대조군으로 한 후 수술 후 1, 3, 6, 12주에 각각 3마리씩 희생하여 육안적, 조직학적 검사 및 평가(Wakitani score)를 시행하였다. 결과: 실험실 하에 키토산-교원질 해면체에서 보다 많은 연골 세포의 생존을 확인했으며, 동물 실험에서 6주 이후부터 육안적 소견 및 조직학적 검사에서 실험군에서 보다 주위 관절 연골과 비슷한 성상을 보였으며 조직학적 평가에선 6주, 12주에 대조군이 평균 10.7, 7.3, 실험군이 평균 8.7, 3.7로 실험군에서 우수하였다(6주: p=0.03, 12주: p=0.02). 결론: 키토산-교원질 해면체는 연골 세포의 지지체로서 적합한 것으로 생각되며 관절 연골 결손에서 이물 반응 없이 초자 연골의 생성 소견을 보여 임상적으로 적용될 수 있는 것으로 생각된다. Purpose: To determine the suitability of using a chatoyant-collagen sponge as a scaffold for transplanting a chondrocyte into a full-thickness articular cartilage defect. Materials and Methods: The in vitro characterization of a chatoyant-collagen sponge infiltrated with the chondrocyte was combined with an in vivo assessment of the early articular cartilage repair in a rabbit's knee by H&E and MTT staining. These porous chatoyant-collagen sponges were implanted into the osteochondral defects made in the left patellofemoral grooves of 12 rabbits. The osteochondral defects were untreated in the right side and used as controls. The experimental animals were sacrificed 1, 3, 6 and 12 weeks after implantation and the repaired tissue was evaluated by a gross and histological evaluation using the Wakitani score. Results: More primary cells cultured from the articular cartilage of the rabbit's knee were found to attach to and survive within a porous chatoyant-collagen sponge than with a chatoyant sponge. In gross and histological examination, the experimental group showed indications of repair, which appeared similar in color and texture to the surrounding articular cartilage. The Wakitani scoring in the experimental group at 6 (Ave. 10.7) and 12 (Ave. 7.3) weeks were superior to those in the control group at 6 (Ave. 8.7) and 12 (Ave. 3.7) weeks (6 wk: p=0.03, 12 wk: p=0.02). Conclusion: Scaffolds composed of porous a chatoyant-collagen sponge enhance the growth of cartilaginous repair and make a milieu for the survival of chondrogenic cells both in vitro and in vivo.