• 대한기계학회논문집A
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• 제37권3호
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• pp.429-436
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• 2013

본 논문에서는 고주파 열처리된 SAE1055 베어링강의 경도에 따른 피로 거동 및 이의 확률론적 평가를 수행하였다. 이를 위하여 경도 수준에 따른 5 종류의 시험편(A : 원재료, B : HV390-전경화, C : HV510-전경화, D : HV700-전경화 및 E : HV-700 표면경화)를 준비하였다. 피로시험은 4 점 회전굽힘 피로시험기를 이용하여 응력비 R=-1 의 조건하에서 수행하였다. 그 결과, SAE1055 강의 피로 거동은 경도에 따라 크게 변화하였으나 HV510 수준이상에서는 피로한도의 증가는 관찰되지 않았다. 또한 피로 파손기구에 대한 경도의 영향을 평가하기 위하여 SEM(scanning electron microscope)을 이용한 파면 관찰을 수행하였다. 피로수명의 통계적 특성은 P-S-N(probabilistic S-N) 곡선을 이용하여 평가되었으며 이에 대한 경도의 영향은 잔류치 해석(residue analysis)을 통하여 수행하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 춘계학술대회 논문집
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• pp.287-290
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• 2005

Once hot forgings for automotive parts such as wheel bearing flange to which cyclic asymmetric bending stress is continuously applied are produced, it is necessary to control their microstructure to obtain superior mechanical properties. It is however hard to control the microstructure uniformly because the strength is reduced as coarsening of ferrite grains. To investigate the microstructural alteration according to process variables during hot working, the variation of the ferrite grain size was studied by utilizing of the computer aided servo-hydraulic Gleeble tester which is hot deformation behavior reproduction equipment. In addition, the effect of the ferrite grain size of raw material on the austenite grain behavior of hot forgings was also examined. The rolling contact fatigue resistance of the induction hardened SAE 1055 steel was compared with the occasion of the same condition of SAE52100 bearing steel. As a result, it was confirmed that the ferrite grain sizes of the forgings depend on the heating temperature and cooling start temperature during hot forging and cooling processes. The induction hardened SAE1055 steel showed a superior rolling contact fatigue resistance to the induction hardened SAE52100 steel. The reason is that SAE1055 steel is freer from the material defect such as segregation than the comparative steel.

• Archives of Plastic Surgery
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• 제49권6호
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• pp.745-749
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• 2022

Background Soft tissue defects of the multiple finger present challenges to reconstruction surgeons. Here, we introduce the use of a lateral arm free flap and syndactylization for the coverage of multiple finger soft tissue defects. Methods This retrospective study was conducted based on reviews of the medical records of 13 patients with multiple soft tissue defects of fingers (n = 33) that underwent temporary syndactylization with a microvascular lateral arm flap for temporary syndactylization from January 2010 to December 2020. Surgical and functional outcomes, times of flap division, complications, and demographic data were analyzed. Results Middle fingers were most frequently affected, followed by ring and index fingers. Mean patient age was 43.58 years. The 13 patients had suffered 10 traumas, 2 thermal burns, and 1 scar contracture. Release of temporary syndactyly was performed 3 to 9 weeks after syndactylization. All flaps survived, but partial necrosis occurred in one patient, who required a local transposition flap after syndactylization release. The mean follow-up was 15.8 months. Conclusion Coverage of multiple finger defects by temporary syndactylization using a free lateral arm flap with subsequent division offers an alternative treatment option.

• Archives of Plastic Surgery
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• 제50권1호
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• pp.10-16
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• 2023

Background The chest wall defects can be caused by various reasons. In the case of malignant tumor resection of the chest wall, it is essential to reconstruct the chest wall to cover the vital tissue and restore the pulmonary function with prevention of paradoxical motion. With our experience, we analyzed and evaluated the results and complications of the chest wall reconstructions followed by malignant tumor resection. Methods From 2013 to 2022, we reviewed a medical record of patients who received chest reconstruction due to chest wall malignant tumor resection. The following data were retrieved: patients' demographic data, tumor type, type of operation, method of chest wall reconstruction of the soft and skeletal tissue and complications. Results There were seven males and six female patients. The causes of reconstruction were 12 primary tumors and one metastatic carcinoma. The pathological types were seven sarcomas, three invasive breast carcinoma, and three squamous cell carcinomas. The skeletal reconstruction was performed in six patients. The series of the flap were eight pedicled latissimus dorsi (LD) myocutaneous flaps, two pectoralis major myocutaneous flap, two vertical rectus abdominis myocutaneous free flap, and one LD free flap. Among all the cases, only one staged reconstruction and successful reconstruction without flail chest. Most of the complications were atelectasis. Conclusion In the case of accompanying multiple ribs and sternal defect, skeletal reconstruction would need skeletal reconstruction to prevent paradoxical chest wall motion. The flap for soft tissue defect be selected according to defect size and location of chest wall. With our experience, we recommend the reconstruction algorithm for chest wall defect due to malignant tumor resection.

• 동의생리병리학회지
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• 제21권4호
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• pp.1051-1055
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• 2007

The diagnosis of pattern identification in Korean Medicine depend on Korean Medicine doctor's experience and information. So, Pattern identification in Korean Medicine raise a question of objectification. This study is to standard stroke pattern identification in Korean Medicine. Weight of symptoms was given important(1points), very important(2points) by stroke specialist. So weight of symptoms is used two method. One is total sum and the other is total man. One had been compared Pattern identification between diagnosed patients by medical specialists and by applicated weight in case report form. The other had been compared Pattern identification between intersubjectivity by medical specialists and by applicated weight in case report form. It is 38%(total sum) or 40%(total man) concordance rate between diagnosed patients by medical specialists and by applicated weight in case report form. It is 82.4% concordance rate between intersubjectivity by medical specialists and by applicated weight in case report form. To acquire more concrete data on this theme, we need further and large scale of prospective researches.