TiAl합금의 Al 피복시 Al확산 피복층의 내고온산화성

이철형,최진일 ( C . H . Lee,J . I . Choe ) 한국열처리공학회 1997 熱處理工學會誌 Vol.10 No.2

The effect of variation of pack activators, compositions, temperature and time on the thickness and structure of aluminide coatings formed on the TiAl alloy was studied in one-step packs and two-step packs containing aluminum for the purpose of improvement of oxidation resistance. The thickness of coating layer was increased with increasing NH₄Cl content up to 3wt% and then it was saturated. Oxidation resistance of coating layers carried out at one step pack was superior to that of ones through of two step pack. The improvement of high temperature oxidation resistance was due to the formation of a protective Al₂O₃ surface layers and coating the alloys with TiAl₃phase.

그리셀증후군 환자에서 I-gel 성문상기도유지기를 사용한 기도관리 -증례보고-

이철형,두아람,우철종,손지선,이상귀,김연동,Lee, Cheolhyeong,Doo, A Ram,Woo, Cheol Jong,Son, Ji-Seon,Lee, Sang-Kyi,Kim, Yeon-dong Korea Convergence Society 2021 한국융합학회논문지 Vol.12 No.10

그리셀 증후군은 환축관절의 비외상성 탈구로 인하여 전신마취 시 경추손상이 발생할 가능성이 있어 신중한 마취관리를 요한다. 이에 우리는 과거에 그리셀 증후군을 받은 진단받은 환자의 전신마취 하 전립선 레이저절제술 시 I-gel을 이용한 기도관리를 성공적으로 진행하였고, 환자는 신경학적 합병증 없이 잘 회복된 사례를 보고하고자 한다. 그리셀 증후군 환자의 마취 관리 시 기도관리를 위하여 I-gel을 사용하는 것이 좋은 대안이 될 수 있을 것이다. Grisel's syndrome is a non-traumatic subluxation of the atlantoaxial joint with an inflammatory condition in the adjacent soft tissues. Due to the instability of the cervical spine, careful airway management is crucial to prevent potential cervical spinal cord injury following airway manipulation. We successfully secured the patient airway using a supraglottic airway device (I-gel) in a patient who had previously diagnosed with Grisel's syndrome. The operation was successfully completed, and the patient recovered without any neurological complications. I-gel can be a good option for airway management during general anesthesia in a patient diagnosed with Grisel's syndrome.

송풍기의 기초지식

이철형,Lee, Cheol-Hyeong 한국설비기술협회 1993 설비 : 공조ㆍ냉동ㆍ위생 Vol.10 No.9

전방 불안정성과 동반된 슬관절 내측 구획 진행성 관절염환자에서 전방십자인대 재건술 및 인공 관절 부분 치환술의 결과 - 3예 보고 -

이철형,송인수,지종훈,김태인,Lee, Chul Hyung,Song, In Soo,Ji, Jong Hun,Kim, Tae In 대한관절경학회 2013 대한관절경학회지 Vol.17 No.1

비교적 젊은 연령의 환자에서 슬관절 내측 구획의 퇴행성 관절염(Kellegrene-Laurence 제 3단계 및 Outerbridge 제 4단계)과 전방십자인대의 파열이 동반되어 전방 불안정성이 있는 3예에서 2예는 전방십자인대 재건술의 6개월 이후 단계적으로 인공 관절 부분 치환술을 시행하고 나머지 1예는 동시에 전방십자인대 재건술 및 부분 치환술을 시행하였으며 수술 전, 후의 International Knee Documentation Committee (IKDC), Lysholm 점수와 최종 추시 상 Hospital for special surgery (HSS)와 knee society score (KSS) 점수를 측정하였다. 저자들의 슬관절의 전방 불안정성과 동반된 내측 구획의 진행성 관절염에서 전방십자인대 재건술과 함께 동시에 또는 단계적으로 시행한 내측 구획 인공 관절 부분 치환술은 슬관절 불안정성과 진행성 관절염에 의한 통증을 동시에 또한 만족스럽게 해결할 수 있는 좋은 선택이라고 사료된다. Three cases who had medial compartment osteoarthritis of the knee (Kellgrene-Laurence grade 3 and Outerbridge grade 4) and anterior instability of the knee due to rupture of the anterior cruciate ligament in relative young ages underwent staged anterior cruciate ligament reconstruction followed by medial unicondylar arthroplasty in 2 cases and simultaneous anterior cruciate ligament reconstruction and unicondylar arthroplasty. We evaluated clinical results some kinds of preoperative and postoperative International Knee Documentation Committee (IKDC), Lysholm score and last follow-up hospital for special surgery (HSS), knee society score (KSS). We consider that medial unicondylar arthroplasty with staged or simultaneous anterior cruciate ligament reconstruction is very good option of the treatment for the anterior instability and pain from advanced arthritis.

유체기계의 고요율에너지기자재 인증 방안

이철형,Lee, Chul-Hyong 한국유체기계학회 2003 한국유체기계학회 논문집 Vol.6 No.1

내측 반월상 연골판 후방 골 기시부 파열의 관절경적 봉합술 후 최소 1년 추시 결과

이철형 ( Chul Hyung Lee ),송인수 ( In Soo Song ),정현윤 ( Hyun Yoon Jeong ),이창수 ( Chang Soo Lee ),이봉주 ( Bong Ju Lee ) 대한스포츠의학회 2011 대한스포츠의학회지 Vol.29 No.1

This study is to evaluate clinical and arthroscopic second-look results of arthroscopic repairs of posterior root tears of medial meniscus which may cause loss of circumferential hoop tension and extrusion of meniscus. From October 2006 to May 2009, fifty-eight patients (59 knees) underwent arthroscopic pull-out repairs. Clinical results were evaluated using Hospital for Special Surgery (HSS) score and International Knee Documentation Committee (IKDC) score for 12-month follow-up. Second-look arthroscopy was done to evaluate meniscal healing in 21 cases. Magnetic resonance imaging (MRI) was performed to assess status of repaired meniscus and tibial tunnel position in 9 patients. Average preoperative HSS score and IKDC score of 59 cases were 69.5 and 36.0, respectively. Average postoperative HSS score and IKDC score of 59 cases had been changed into 90.3 (p<0.001) and 66.8 (p<0.001), respectively. Second-look arthroscopies revealed complete or incomplete healing except one case. Two patients showed increased one grade according to the Kellgren-Lawrence radiologic classification system and others showed no change. Of 9 patients who performed MRI, six patients showed complete healing. The average position of tibial tunnel was 4.8 mm anterior and 5.7 mm medial to center of posterior cruciate ligament. Arthroscopic pull-out repair technique using transtibial tunnel seems to be simple and effective procedure for posterior root tear of medial meniscus. Further evaluation of arthroscopic repair of posterior root tear of medial meniscus should be needed to prove the effectiveness on the prevention of osteoarthritis of knee.

불안정성 원위 요골 골절의 치료에 있어 한국형 이중 연골하 지지고정 전방 금속판의 임상적 및 방사선학적 결과

이철형(Chul-Hyung Lee),정덕희(Deukhee Jung),안충한(Chung-Han An),정의탁(Uitak Jeong) 대한정형외과학회 2020 대한정형외과학회지 Vol.55 No.6

목적: 본 연구는 요골 원위부 골절에 대해 국내에서 이중 연골하 지지고정 개념으로 개발된 전방 잠김 금속판의 수술 후 정복 유지효과 및 이에 영향을 줄 수 있는 요인들에 대해 평가해 보고자 하였다. 대상 및 방법: 2017년 7월부터 2018년 12월까지 요골 원위부 골절 환자 중 관혈적 정복 및 금속판 고정술을 시행한 54예를 대상으로 하였다. 수술 직후와 최종 추시 시 촬영한 단순방사선 사진을 이용해 요골 길이, 요골경사, 수장측 경사, 척골 변위, 원위 배측 피질 거리(distal dorsal cortical distance)를 측정하여 골절 정복 유지 효과에 대해 평가하였다. 환자 나이, 골절 분류, 금속판 위치를 기준으로 전체 환자군을 세부 그룹으로 나누어 비교함으로써 각 요인이 골절 정복 유지에 미치는 영향을 분석하였다. 결과: 수술 직후 원위 배측 피질 거리는 평균 5.91 mm (표준 편차, ±1.95 mm)로 측정되었으며 요골 길이(p=0.038), 척골 변위(p=0.001)는 수술 직후와 최종 추시 시 촬영한 단순 방사선 사진에서 유의한 차이가 확인되었다. 전체 환자군을 각 요인에 따라 세부 그룹으로 나누어 평가했을 시 척골 변위는 나이가 65세 이상이거나 AO/OTA 분류 C3형에 해당하는 경우 혹은 금속판 위치가 Soong classification grade 0에 해당하는 경우 수술 직후에 비해 최종 추시 시 유의하게 증가하였다(p=0.007, p=0.012, =p0.046). 결론: 국내에서 이중 연골하 지지고정 개념으로 생산된 전방 잠김 금속판을 이용하여 요골 원위부 골절 정복술을 시행하는 경우 충분한 정복을 확보할 수 있으며 골절 정복 유지에 대해 전반적으로 긍정적인 결과를 보이나, 환자가 고령인 경우, 관절 내 골절의 분쇄 정도가 심한 경우, 금속판이 분수령선의 근위부에 위치한 경우에 척골 변위의 증가를 보여 요골 월상골와의 정복 유지를 위한 고려가 필요하다. Purpose: The aim of this study was to assess the effectiveness of domestically developed volar locking plate which has the concept of double-tiered subchondral support (DSS) in maintaining the reduction after distal radial fracture surgery. Materials and Methods: From July 2017 to December 2018, 54 patients were assessed. Plain radiographs were obtained immediately after surgery and at the last follow-up, and the radiographic parameters were measured in those images: radial length, radial inclination, volar tilt, ulnar variance, and distal dorsal cortical distance. The patients were subdivided into their age, type of fracture, and the position of the plate to evaluate the influence of each factors on the reduction maintenance. Results: Distal dorsal cortical distance in radiographs after the surgery was 5.91 mm (standard deviation, ±1.95 mm) on average. Significant differences in the radial length (p=0.038) and ulnar variance (p=0.001) were observed between immediately after surgery and at the last follow-up. When the parameters were evaluated by dividing the patients into subgroups according to the three specific factors, the ulnar variance showed a significant increase at the last follow-up when the patients were included 65-years-old or older. AO/OTA type C3 fracture, and Soong classification grade 0 plate position (p=0.007, p=0.012, p=0.046, respectively). Conclusion: Using the domestically developed DSS-type volar locking plate, significant reduction after distal radial fracture surgery could be maintained successfully. On the other hand, further study will be needed to determine about the reduction loss of the lunate facet identified in special cases that deal with fractures in elderly patients, unstable AO/OTA type C3 distal radial fractures, and Soong classification grade 0 plate position.

프란시스수차의 국산화개발 연구

이철형(Lee Chull-Hyung),박완순(Park Wan-Soon) 한국태양에너지학회 2009 한국태양에너지학회 학술대회논문집 Vol.- No.-

The Francis type hydro turbine with vertical axis has been designed and analized for hydraulic performance verification. The guide vane angle of turbine casing were designed to be varied according to the condition of head and flowrate. When the changes in flowrate and output were comparatively large, the efficiency drop were small, so the efficiency characteristics and stability of the entire operating condition were maintained in good condition. These results showed that the developed hydro turbine in this study will be suitable for small hydro power stations with medium and high head such as agricultural reservoirs and large dam.

하수처리수를 이용한 소수력발전소 설계 및 성능예측

이철형(Lee, Chul-Hyung),박완순(Park, Wan-Soon),김원경(Kim, Won-Kyoung),김정연(Kim, Jeong-Yeon),채규정(Chae, Kyu-Jung) 한국태양에너지학회 2013 한국태양에너지학회 논문집 Vol.33 No.2

A methodology to predict the output performance of small hydro power plant using treated effluent in waste water treatment plant has been studied. Existing waste water treatment plant located in Kyunggi-Do were selected and the output performance characteristics for these plants were analyzed. Based on the models developed in this study, the hydrologic performance characteristics for SHP sites have been analyzed. The results show that the flow duration characteristics of small hydropower plant for waste water treatment plant have quite differences compared with small hydropower plant for the river. As a result, it was found that the developed model in this study can be used to analyze the output characteristics for small hydro power in waste water treatment plant. Additionally, primary design specifications such as design flowrate, capacity, operational rate and annual electricity production were estimated and discussed. It was found that the models developed in this study can be used to decide the design performance of small hydropower plant for waste water treatment plant effectively.

전산유동해석을 통한 HRSG 유동 개선 및 탈질설비 최적화 연구

이철형(Cheolhyeong Lee),박종민(Jongmin Park),류창국(Changkook Ryu) 한국에너지기후변화학회 2022 한국에너지기후변화학회 학술대회 Vol.2022 No.5