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골이식 없이 국소마취하에 경피적 나사못 고정으로 치료한 주상골 요부 골절 불유합의 결과
차정권,박지강,최승명,양재영 대한수부외과학회 2017 대한수부외과학회지 Vol.22 No.2
Purpose: The purpose of this study was to analyze the results of patients with scaphoid waist nonunion treated with percutaneous screw fixation without bone grafting under local anesthesia. Methods: We enrolled scaphoid waist nonunion of 15 patients which had no deformity, displacement, evidence of avascular necrosis and bone cyst under 5 mm on its radiological study. All patients were male with an average age of 28.9±6.2 years (range, 17–38 years). The mean time to surgery from initial injury was 10.8±2.2 months (range, 6–14 months). All patients were treated with percutaneous screw fixation without bone grafting via volar approaching under local anesthesia and postoperative radiographs were reviewed and documented the flexion and extension arcs of the injured wrist and uninjured wrist, disability of the arm, shoulder and hand (DASH) score at final follow-up. Results: All 15 patients showed radiological union at an average 5.5±1.0 months. At 12 months follow-up, the flexion and extension arcs of the injured wrist were 95% and 98.5% of the uninjured wrist. The average DASH score at final follow-up was 7±3.9 (range, 0–15). None of these patients showed any complications associated with surgery. Conclusion: Percutaneous screw fixation without bone grafting under local anesthesia was reliable primary treatment method for scaphoid waist nonunion without displacement or deformation in the fracture site. 목적: 주상골 요부 골절 후 발생한 불유합에 대하여 국소마취하에 골이식 없이 시행한 경피적 나사못 내고정술의 결과를 평가하였다. 방법: 주상골 요부 골절 불유합 환자 중 골절부에 전위나 변형이 없고 5 mm 이하의 골낭종, 무혈성 괴사와 관절증의 증거가 없는 15예의 환자를 대상으로 하였다. 모두 남성이었고 평균 나이는 28.9±6.2세(범위, 17-38세), 수상 후 수술까지 기간은 평균 10.8±2.2개월(범위, 6-14개월)이었다. 국소마취하에 수장측으로 접근하여 골이식 없이 경피적 나사못고정술을 시행하였고 골유합 및 변형 여부를 방사선학적으로 평가하였다. 최종 추시에서 DASH score와 건측 대비 환측의 수근관절 운동 범위를 측정하였다. 결과: 모든 환자에서 술 후 평균 5.5±1.0개월에 방사선학적 골유합을 얻었다. 최종 추시 12개월에 건측 대비 환측의 수근관절 굴곡과 신전은 각각 95%와 98.5%로 회복되었고 평균 DASH score는 7±3.9점(범위, 0-15점)이었다. 모든 환자에서 수술과 관련된 합병증은 없었다. 결론: 골이식 없이 국소마취하에 시행하는 경피적 나사못 고정 방법은 골절부에 전위나 변형이 없는 주상골 요부 불유합의 치료에 일차적으로 시도해볼 수 있는 적절한 치료방법이라 생각한다.
휠 제동 장치의 스퀼 소음 해석을 위한 해석 모델 구축
차정권(Cha Jung-kwon),박영일(Park Yeong-il),이동균(Lee Dong-Kyun),조동현(Cho Dong-Hun),김기남(Kim Ki-Nam),백진성(Beak Jin-Sung) 한국철도학회 2008 한국철도학회 학술발표대회논문집 Vol.- No.-
Squeal of disk brake is a noise and self excited vibration with frequency range of 1~10Khz cause by the friction force between the disk and the pad of the automobile. Passengers in a cehicle feel uncomfortable. In this paper modal analysis of wheel brake system was performed in order to prediction of squeal phenomenon. It was shown that the prediction of system instability is possible by FEM. finite element model of that brake system was made. Some parts of a real brake was selected and modeled. The normal mode analysis method performs analyses of each brake system component. Experiment of modal analysis was performed for each brake components and experimental results were compared with analytical result from FEM.
차정권(Jungkwon Cha),김기남(Ki-nam Kim),조동현(Yeong-il Park),박영일(yeong-il Park) 한국자동차공학회 2008 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-
Squeal, a kind of self-excited vibration, is generated by the friction between the disc and the friction materials. It occurs at the ending stage of the braking process, and radiates and audible frequency range of 1 ㎑ to 10 ㎑. Squeal is generated from unstability because of the coupling between the translation and rotation of the system. This instability is caused by the follower force and follower force is normal component of the friction force. In this paper modal analysis of wheel brake system was performed in order to prediction of squeal phenomenon. It was shown that the prediction of system instability is possible by FEM.A finite element model of that brake system was made. SOme parts of a real brake was selected and modeled. The normal mode analysis method performs analyses of each brake system component. Experiment of modal analysis was performed for each brake com
차정권(Kwon-Jung Cha),윤일로(Il-Ro Yoon),김동활(Dong-Howal Kim),후쿠모토(Yozo Fukumoto) 한국철도학회 2011 한국철도학회 학술발표대회논문집 Vol.2011 No.5
Light Rail Vehicle(LRT) is “New Transit System” that has transportation capacity as well as physical size of vehicle is in-between bus and subway. The demand of LRT system is increasing rapidly; both domestically and internationally. Reason being is that it is more economical and eco-friendly compare to existing heavy rail vehicle. Especially, Busan Subway Line 4 K-AGT (Rubber-tired LRT) being the first of its kind to start revenue service in Korea, it is very much likely that application of its demand will continue to increase. Considering its trend, study to reduce implementation cost of LRT is being pursued in many different aspects; reducing construction cost is one that aspect. In this study, on-site application of ‘Up-Down Turnout System’ implementation research has been carried out which can replace existing ‘Left-Right Turnout System’. When safety of its type gets verified, application of this system to line which intends to use K-AGT, Shin-Lim Line and Dong-Book Line, expects to save its construction cost. This thesis paper reports ongoing research of AGT ‘Up-Down Turnout System’ development and main component design factors, fundamental principle, performance test result.
차정권(Cha, Jung-Kwon),박영일(Park, Yeong-Il) 한국소음진동공학회 2010 한국소음진동공학회 논문집 Vol.20 No.1
Squeal, a kind of self-excited vibration, is generated by the friction between the disc and the friction materials. It occurs at the ending stage of the braking process, and radiates and audible frequency range of 1 kHz to 10 kHz. Squeal is generated from unstability because of the coupling between the translation and rotation of the system. This instability is caused by the follower force and follower force is normal component of the friction force. In this paper modal analysis of wheel brake system was performed in order to predict the squeal phenomenon. It was shown that the prediction of system instability is possible by FEM. A finite element model of that brake system was made. Some parts of a real brake was selected and modeled. Modal analysis method performs analyses of each brake system component. Experimental modal analysis was performed for each brake components and experimental results were compared with analytical results from FEM. To predict the dynamic unstability of a whole system, the complex eigenvalue analysis for assembly modeling of components confirmed by modal analysis is performed. The finite element models of the disk brake assembly have been constructed, and the squeal noise problems have been solved by complex eigenvalue analysis. The complex eigenvalue analysis results compared with real train test.
차정권(Jungkwon Cha),정상진(Sangjin Jung),최장원(Jangwon Choi),이희용(Heeyong Lee) 한국자동차공학회 2018 한국자동차공학회 학술대회 및 전시회 Vol.2018 No.11
This paper shows a whole noise developing procedure and items for the new developed Mid-CVT. Through the case FRF test, the robust design of the CVT was investigated. To reduce the planetary gear noise, the gear tooth-contact pattern test was performed. Through the gear tooth-contact pattern test, the new specification was developed. And all gear grinding methods are also used. Due to demands for reducing the serious abnormal chain-belt noise some special test method are developed and applied. Though the control of guiderail length and chain pitch length, chain-belt noise could be handled and reduced effectively. The whole developing process and results will offer good guides to the engineers who develop the new CVT.
차정권(Cha Jung-kwon),박영일(Park Yeong-il),이동균(Lee Dong-Kyun),조동현(Cho Dong-Hun) 한국철도학회 2009 한국철도학회 세미나자료 Vol.2009 No.5
Passengers in a vehicle feel uncomfortable due to squeal noise. Squeal noise, a kind of self-excited vibration, is generated by the friction force between the disc and the pad of the automobile. In this paper, modal analysis of wheel brake system was performed in order to prediction of squeal phenomenon. It was shown that the prediction of system instability is possible by FEM. Finite element model of that brake system was made. Some parts of a real brake was selected and modeled. The normal mode analysis method performs analyses of each brake system component. Experiment of modal analysis was performed for each brake components and experimental results were compared with analytical result from FEM. The complex eigenvalue analysis results compared with braking test. The analysis results show good correlation with braking test for the squeal frequency at an unstable mode.
차정권(Jungkwon Cha),정상진(Sangjin Jung),조명수(Myungsoo Cho),최인혁(Inhyuk Choi) 한국자동차공학회 2016 한국자동차공학회 학술대회 및 전시회 Vol.2016 No.11
Reduction of planetary gear noise for the automatic transmission was investigated using dynamic stiffness strengthening of the transmission case and the mounting bracket. Dynamic stiffness of case was improved by the reinforcing rib and shape change, through the FRF test, and 1’st mode frequency was also improved by the shape change of vehicle mounting bracket. After that, noise reduction was confirmed by the comparing before and after vibration and noise level of automatic transmission at the anechoic chamber and vehicle. Test results show that gear noise of transmission was improved 10dB at anechoic chamber and 8dB reduced in vehicle noise respectively.