• 대한기계학회논문집A
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• 제24권2호
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• pp.378-385
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• 2000

Fracture resistance (J-R) curves, which are used for elastic-plastic fracture mechanics analyses, decreased under tension-compression loading condition. This phenomenon was proved by several former researches, but the causes have not been clear yet. The objective of this paper is to investigate the cause of this phenomenon. On the basis of fracture resistance curve test results, strain hardening hypothesis, stress redistribution hypothesis and crack opening hypothesis were built. In this study, hardness tests, Automated Ball Indentation(ABI) tests, theoretical stress field analyses, and crack opening analyses were performed to prove the hypotheses. From this study, strain-hardening of material, generation of tensile residual stress at crack tip, and crack opening effects are proved as the causes of the decrease hypothesis.

• 대한추나의학회지
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• 제3권1호
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• pp.167-174
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• 2002

흉요추 이행부의 안정성 압박골절은 통증의 소실과 후만각 증가 억제에 의한 척추의 안정화이다. 이의 원인을 후방인대의 손상에 의한 손상으로 보고 프로로테라피(Prolotherapy)로 이의 치료를 시행 할 수 있다고 생각되며 한방적인 방법으로 화침을 적용할 수 있었다. 최근 저자는 흉요추 이행부의 안정성 압박골절에 의한 요배통 환자를 발견하고 화침치료를 통해 증세 회복에 도움이 되었기에 치료내용과 경과를 문헌고찰과 함께 보고하는 바이다.

• Journal of Korean Neurosurgical Society
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• 제60권5호
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• pp.498-503
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• 2017

Objective : The purpose of the present study was to compare inter-fragmentary compression pressures after fixation of a simulated type II odontoid fracture with the headless compression Herbert screw and a half threaded cannulated lag screw. Methods : We compared inter-fragmentary compression pressures between 40- and 45-mm long 4.5-mm Herbert screws (n=8 and n=9, respectively) and 40- and 45-mm long 4.0-mm cannulated lag screws (n=7 and n=10, respectively) after insertion into rigid polyurethane foam test blocks (Sawbones, Vashon, WA, USA). A washer load cell was placed between the two segments of test blocks to measure the compression force. Because the total length of each foam block was 42 mm, the 40-mm screws were embedded in the cancellous foam, while the 45-mm screws penetrated the denser cortical foam at the bottom. This enabled us to compare inter-fragmentary compression pressures as they are affected by the penetration of the apical dens tip by the screws. Results : The mean compression pressures of the 40- and 45-mm long cannulated lag screws were $50.48{\pm}1.20N$ and $53.88{\pm}1.02N$, respectively, which was not statistically significant (p=0.0551). The mean compression pressures of the 40-mm long Herbert screw was $52.82{\pm}2.17N$, and was not statistically significant compared with the 40-mm long cannulated lag screw (p=0.3679). However, 45-mm Herbert screw had significantly higher mean compression pressure ($60.68{\pm}2.03N$) than both the 45-mm cannulated lag screw and the 40-mm Herbert screw (p=0.0049 and p=0.0246, respectively). Conclusion : Our results showed that inter-fragmentary compression pressures of the Herbert screw were significantly increased when the screw tip penetrated the opposite dens cortical foam. This can support the generally recommended surgical technique that, in order to facilitate maximal reduction of the fracture gap using anterior odontoid screws, it is essential to penetrate the apical dens tip with the screw.

• 한국안전학회지
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• 제17권4호
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• pp.45-51
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• 2002

In this study, the fracture characteristics of carbonized silicon grinding wheels were examined with tensile, compression, impact and bending test. The experiment was performed for the various grinding wheels with grain size #46, #80, and grade H, L, P, and one vitrified bond and one structure No.7. Also the centrifugal fracture rpm of carbonized silicon grinding wheels were measured and compared with the calculated values for the various wheel diameters and thicknesses. The results showed that the fracture tensile strength was $1.5~2.0Kg_f/mm^2$, and it was increased by decreasing grain size and increasing grade. The fracture compression loads were $1,600~3,000Kg_f$, and the inner stress was higher than outer's. And the absorption energy of impact test was 3.3~4.7 J, and it was increased by decreasing grain size but it was not effected by grade. The fracture bending stress was $0.1~0.2Kg_f/mm^2$, and it was increased by decreasing grain size and increasing grade. The centrifugal fracture rpm of carbonized silicon grinding wheel was about 8,500~12,000 and agreed well with the calculated value, and it was increased by decreasing diameter. However, it was almost constant for the reduction of wheel thickness.

• 소성∙가공
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• 제21권5호
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• pp.285-290
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• 2012

In spite of progress in predicting ductile failure, the development of a macroscopic yield criterion to describe damage evolution in HCP (hexagonal close-packed) materials remains a challenge. HCP materials display strength differential effects (i.e., different behavior in tension versus compression) in their plastic response due to twinning. Cazacu and Stewart(2009) developed an analytical yield criterion for porous material containing randomly distributed spherical voids in an isotropic, incompressible matrix that shows tension-compression asymmetry. The goal of the calculations in this paper is to investigate the effect of the tension-compression asymmetry on necking induced by void nucleation, evolution and consolidation. In order to investigate the effect of the tension-compression asymmetry of the matrix on necking and fracture initiation, three isotropic materials A, B, and C were examined with different ratios of tension-compression asymmetry. The various types of material had BCC, FCC, and HCP crystal structures, respectively. The ratio between tension and compression in plastic flow significantly influences the fracture shape produced by damage propagation as well as affecting the localized neck.

• 한국구조물진단유지관리공학회 논문집
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• 제11권6호
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• pp.87-94
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• 2007

폐콘크리트로부터 생산된 순환골재의 사용은 환경보존과 자원의 재활용 관점에서 매우 유용하며, 순환골재 콘크리트에서 압축, 인장, 휨 및 부착강도, 탄성계수 등이 중요한 기계적 특성요소로 작용하게 된다. 특히 압축을 받는 순환골재 콘크리트의 응력-변형률 관계 및 파괴진전 양상 규명은 순환골재 콘크리트를 사용한 구조물 설계 및 수치해석 등 이론적 연구에서도 매우 중요한 의미를 가진다. 따라서 본 연구에서는 순환골재 콘크리트의 파괴진전특성을 규명하기 위하여 압축하중을 받는 콘크리트의 미세균열 등 손상특성을 검출하기 위하여 AE 기법을 사용하였다. 압축거동특성 및 AE 신호특성을 분석한 결과, 순환굵은골재 콘크리트의 균열 및 파괴거동은 천연 및 순환잔골재를 사용한 콘크리트와 상이한 것으로 나타났다.

• 대한족부족관절학회지
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• 제9권1호
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• pp.99-104
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• 2005

Purpose: The purpose of this study was to investigate usefulness of locking compression plate (LCP) as an open reduction technique by evaluating clinical results obtained from the patients with lateral malleolar fracture treated by internal fixation using LCP after open reduction. Materials and Methods: Among the patients with lateral malleolar fracture, the 28 patients who were treated by internal fixation using Locking compression plate after an open reduction and were able to be followed up for more than 6 months were included in this study. Final postoperative evaluation was done based on the Meyer's clinical and radiologic evaluation system. Results: All cases achieved anatomical reduction and fixation of the reduction postoperatively. 28 minutes were taken meaningly from the incision to the fixation of LCP plate after the anatomical reduction. Everage bony union time was 8.2 weaks, and the result was excellent in 23 cases (82%), good in 5 cases (17%) and poor result was abscent according to the criteria of Meyer et al. One case of post traumatic arthritis and one case of superficial infection on the operation site were found, but non-union, delayed union and malunion were not occurred. Conclusion: The internal fixation after open reduction using LCP is an effective treatment method in treating lateral malleolar fracture of the ankle since it offers advantages including easy application and a greater stability due to its capability of maintaining exact anatomical reduction even though the screw does not penetrate the medial cortex of fibular to add the stability and rigidity of the fixation.

• Journal of Trauma and Injury
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• 제27권4호
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• pp.186-191
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• 2014

Purpose: The objectives of this study were to assess pain relief according to the time after kyphoplasty and to evaluate the factors affecting pain relief after kyphoplasty in the treatment of a single-level osteoporotic vertebral compression fracture. Methods: A retrospective review of 34 kyphoplasties for single-level osteoporotic vertebral compression fractures was performed. Pain relief was assessed by using the visual analogue scale (VAS) at preoperatively and postoperatively at 6 weeks, 3 months, and 6 months. Associated factors, including age, sex, pain duration, bone mineral density, and cement leakage, were evaluated using the patients' medical records. Statistical analyses were conducted using the paired t-test to assess pain relief and using the independent t-test and Pearson's correlation coefficient to evaluate the relationship between those factors and pain relief. Results: Preoperatively, the mean VAS score was 7.06. Postoperatively, it declined to 3.66 (p=0.001), 2.81 (p=0.001) and 2.24 (p=0.001) at 6 weeks, 3 months and 6 months, respectively. Also, statistically significant pain relief was observed during the periods from 6 weeks to 3 months (p=0.001) and from 3 months to 6 months (p=0.001). However, reduction of the VAS score showed no significant correlation with age, sex, pain duration, bone mineral density, or cement leakage (p>0.05). Conclusion: Our study suggests that a kyphoplasty may be effective in osteoporotic vertebral compression fracture patients with acute pain and that after the kyphoplasty, pain is reduced remarkably for 6 weeks and then continuously for 6 months.

• 대한한방내과학회지
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• 제40권5호
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• pp.841-850
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• 2019

Objective: The aim of this study was to report the effects of traditional Korean medicine as a treatment for the pain of a compression fracture in a patient with metastatic prostate cancer. Methods: A 60-year-old male patient with a compression fracture was treated with herbal medicines, acupuncture, and pharmacopuncture for 25 days. His chief complaints were severe low back pain, pain and numbness in both legs, and right groin pain. The effect of treatment was evaluated by the numerical rating scale (NRS) score for pain, the Oswestry Disability Index (ODI) score, and blood test results (CBC-diff count, CRP, ESR, etc.). Results: After 25 days of inpatient treatment, the patient's pain was controlled. The NRS and ODI scores were lower and most pathological symptoms had decreased. Conclusions: Traditional Korean medicine can be a solution for patients with compression fractures arising from metastasis of prostate cancer to the spine.

• 대한정형외과학회지
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• 제55권1호
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• pp.90-94
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• 2020

경피적 풍선 척추 성형술은 병적 척추체 압박 골절에서 통증 호전을 위한 시술로 사용되고 있다. 시술 후 합병증으로 시멘트가 피질 결손 부위를 통해 누출되면서 발생한 신경 압박 사례가 종종 보고되고 있다. 하지만 시멘트 누출이 아닌 종양성 병변이 후방 전위되면서 발생한 신경 압박에 대한 보고는 거의 없었다. 이에 저자들은 병적 척추체 압박 골절로 수술 전에 신경 압박이 없던 65세 여자 환자에서 경피적 풍선 척추 성형술 시행 후 종양성 병변이 후방 전위되면서 발생한 마미 증후군으로 추가 수술을 시행한 증례를 보고한다. 시술 후 촬영한 자기공명영상에서 피질골을 뚫고 척수강 내로 후방 전위된 종양성 병변이 확인되었다