• 대한기계학회논문집A
• /
• 제23권7호
• /
• pp.1112-1119
• /
• 1999

Fracture resistance(J-R) curves, which are used for the elastic-plastic fracture mechanics analyses, are known to be dependent on the cyclic loading history. The objective of this paper is to study the effect of reverse cyclic loading on J-R curves in CT specimens. The effect of two parameters was observed on the J-R curves during the reverse cyclic loading. One was the minimum-to-maximum load ratio(R) and the other was the incremental plastic displacement(${\delta}_{cycle}/{\delta}_i$), which is related to the amount of crack growth that occurs in a cycle. Fracture resistance test on CT specimens with varying load ratio and incremental plastic displacement were performed. For the SA 516 Gr. 70 steel, the results showed that the J-R curves were decreased with decreasing the load ratio and the incremental plastic displacement. When the load ratio was set to -1, the results of the J-R curves and the $J_i$ value were about $40{\sim}50$ percent of those for the monotonic loading condition. Also on condition that the incremental plastic displacement reached 1/40, the J-R curves and the $J_i$ value were about $50{\sim}60$ percent of those for the incremental plastic displacement of 1/10.

• 한국방사성폐기물학회:학술대회논문집
• /
• 한국방사성폐기물학회 2009년도 학술논문요약집
• /
• pp.187-187
• /
• 2009

Opening of fractures induced by shear dilation or normal deformation can be a significant source of fracture permeability change in fractured rock, which is important for the performance assessment of geological repositories for spent nuclear fuel. As the repository generates heat and later cools the fluid-carrying ability of the rocks becomes a dynamic variable during the lifespan of the repository. Heating causes expansion of the rock close to the repository and, at the same time, contraction close to the surface. During the cooling phase of the repository, the opposite takes place. Heating and cooling together with the, virgin stress can induce shear dilation of fractures and deformation zones and change the flow field around the repository. The objectives of this work are to examine the contribution of thermal stress to the shear slip of fracture in mid- and far-field around a KBS-3 type of repository and to investigate the effect of evolution of stress on the rock mass permeability. In the first part of this study, zones of fracture shear slip were examined by conducting a three-dimensional, thermo-mechanical analysis of a spent fuel repository model in the size of 2 km $\times$ 2 km $\times$ 800 m. Stress evolutions of importance for fracture shear slip are: (1) comparatively high horizontal compressive thermal stress at the repository level, (2) generation of vertical tensile thermal stress right above the repository, (3) horizontal tensile stress near the surface, which can induce tensile failure, and generation of shear stresses at the comers of the repository. In the second part of the study, fracture data from Forsmark, Sweden is used to establish fracture network models (DFN). Stress paths obtained from the thermo-mechanical analysis were used as boundary conditions in DFN-DEM (Discrete Element Method) analysis of six DFN models at the repository level. Increases of permeability up to a factor of four were observed during thermal loading history and shear dilation of fractures was not recovered after cooling of the repository. An understanding of the stress path and potential areas of slip induced shear dilation and related permeability changes during the lifetime of a repository for spent nuclear fuel is of utmost importance for analysing long-term safety. The result of this study will assist in identifying critical areas around a repository where fracture shear slip is likely to develop. The presentation also includes a brief introduction to the ongoing site investigation on two candidate sites for geological repository in Sweden.

• 대한간호학회지
• /
• 제45권2호
• /
• pp.293-305
• /
• 2015

Purpose: The aim of the study was to assess and identify gender differences in factors associated with prevalence, awareness, and treatment of osteoporosis. Methods: Data for 3,071 men and 3,635 women ($age{\qeq}50$) from the Korea National Health and Nutrition Examination Survey 2008~2011 were included. Osteoporosis was defined by World Health Organization T-score criteria. Impact factors and odds ratios were analysed by gender using multivariate logistic regression. Results: Osteoporosis prevalence rates were 7.0% in men and 40.1% in women. Osteopenia rates were 45.5% and 46.0% respectively. Among respondents with osteoporosis, 7.6% men and 37.8% women were aware of their diagnosis. Also 5.7% men with osteoporosis and 22.8% women were treated. Higher prevalence was found among respondents who were older, at lower socioeconomic levels, with lower body mass index and shorter height in both genders, and among women with fracture history, and non-hormonal replacement therapy. Awareness and treatment rates for the risk groups were similar compared to the low risk controls for both genders. Fracture history increased awareness and treatment rates independently for both genders. Women with perceived poor health status and health screening had increased awareness and treatment rates, but not men. Conclusion: Results indicate that postmenopausal women have a higher prevalence of osteoporosis than men and awareness and treatment rates were higher than for men. Despite gender difference in prevalence, osteoporosis was underdiagnosed and undertreated for both genders. Specialized public education and routine health screenings according to gender could be effective strategies to increase osteoporosis awareness and treatment.

• 대한기계학회논문집A
• /
• 제38권10호
• /
• pp.1157-1162
• /
• 2014

시간 이력 지진해석시 두 가지 가진 방법론[유효하중법(또는 관성법), 거대질량법]이 적용되고 있는데 균열 없는 구조물에 대해서만 두 가지 가진 방법론의 타당성을 확인한 바 있으나, 균열로 인해 강성이 변화하는 균열 배관에 대해서는 가진 방법론의 타당성에 대한 연구가 수행된 바 없다. 본 연구에서는 시간이력 Implicit 동적 탄성 지진해석을 통해 탄성 파괴역학 측면에서 관통 균열 배관에 대한 두 가지 가진 방법론의 타당성을 평가하였다. 평가 결과, 거대질량의 크기와 최대 시간 증분이 적절히 선정된다면 균열 배관에 대해서도 두 가지 가진 방법론이 모두 동일한 결과를 도출함을 확인하였다.

• 한국산학기술학회논문지
• /
• 제14권10호
• /
• pp.4943-4952
• /
• 2013

본 연구는 국민건강영양조사 제 4기 2 3차년도, 제 5기 1차 년도에 참여한 60세 이상 여성노인을 대상으로 하였다. 연구의 목적으로는 신체계측, 생활습관, 식이섭취, 골절 과거력, 골다공증 가족력, 병력, 월경력 및 산과적 요인 등의 제 요인들과 대퇴경부 골밀도와 요추골밀도의 관련성을 알아보고자 시도하였다. 각 변수의 단위별 BMD의 변화를 표현하기 위해 비율차이 계산식 ${\beta}{\times}$(단위/BMD의 평균)를 이용한 다중선형회귀분석을 실시하였다. 모든 연속 변수의 단위는 1 표준편차를 사용하였다. 연구결과, 대퇴경부 및 요추 골밀도에 조사된 각 독립변수 중 여성노인의 골밀도에 가장 큰 영향을 미치는 것은 대퇴경부 부위에서는 제지방량(B: 0.257), 요추 부위에서는 체지방(B: 0.237)으로 확인되었다. 따라서 여성노인에서는 제지방량을 늘리고, 적절한 체중을 유지하는 것이 골다공증을 예방하는 효과적인 방안이 될 것이다.

• 지질공학
• /
• 제26권1호
• /
• pp.33-49
• /
• 2016

연구지역인 울산시 신암리 지역은 각섬석화강암을 기반암으로 하여 이를 관입하고 있는 규장질 및 고철질 암맥, 열수주입과 관련된 석영맥 그리고 단층파쇄대가 형성되어 있다. 이 지역에는 역학적으로 균질한 화강암이 우세하게 발달하는 지역이지만 지역적으로 발달한 암맥의 영향으로 불연속면을 형성하여 지반의 불안정과 단층의 재활을 유도하였다. 이러한 화강암 내 불연속면에 집중된 응력의 특성을 해석하기 위하여 우리는 N-S방향으로 트렌치를 개설하였고, 이를 통해 노출된 지질구조요소들을 활용하여 단열발달사 및 이와 관련된 고응력 방향을 추론하기 위하여 기하학적 및 운동학적 분석을 실시하였다. 이를 위해 먼저 연구지역에 발달하는 단열들 간의 상호절단관계와 인접한 지역에서 수행된 선행연구들을 토대로 구조변형사를 수립하였으며, 단열발달 시 작용한 고응력 방향을 유추하여 최대수평주응력(σ_Hmax)과 최소수평주응력(σ_Hmin)으로 나타내었다. 단열분석 결과 (1) 기반암인 각섬석화강암 관입 이후 적어도 NNE-SSW, ENE-WSW, E-W, WNW-ESE 방향의 단열들이 존재하였을 것으로 추정되며, 이후 (2) NNE 내지 N-S 방향의 σ_Hmax/E-W 방향의 σ_Hmin 하에서 NNE-SSW 및 E-W방향의 규장질 암맥이 관입하고, (3) E-W 내지 ENE-WSW 방향의 σ_Hmax/N-S 내지 NNW-SSE 방향의 σ_Hmin 하에서 E-W 내지 ENE-WSW 방향의 고철질 암맥이 관입하였으며, (4) E-W 내지 WNW-ESE 방향의 σ_Hmax/N-S 내지 NNE-SSW 방향의 σ_Hmin 하에서 열수주입과 관련된 석영맥들의 발달, ENE-WSW 방향의 주단층 우수향 운동이 있었고, (5) NNE-SSW 내지 NE-SW 방향의 σ_Hmax/WNWESE 내지 NW-SE 방향에서 작용하는 σ_Hmin 하에서 E-W 주향의 열수관련 석영맥 좌수향 재활과 ENE-WSW 방향 주단층의 정이동성 좌수향 재활운동이 있었고, 최종적으로 (6) NW-SE 방향의 σ_Hmax/NE-SW 방향의 σ_Hmin 하에서 ENE-WSW 방향의 주단층은 역이동성 우수향 재활을 겪은 것으로 해석되었다. 단열발달사 및 고응력장 복원결과는 기존에 제시된 포항-울산 지괴내의 신생대 지구조운동사와 잘 대비된다. 이는 양산단층과 울산단층으로 경계된 울산단층의 남쪽 지역이 신생대에 포항-울산 지괴와 유사한 지구조 운동을 겪었음을 시사한다. 이러한 연구결과는 본 연구지역과 인접한 주요 시설물의 안정성 평가 및 차후의 지진재해 대책을 수립하는데 있어 중요한 역할을 할 수 있을 것으로 사료된다.

• Journal of Acupuncture Research
• /
• 제37권3호
• /
• pp.187-192
• /
• 2020

Sacral insufficiency fractures (SIF) are a common, but often underdiagnosed source of lower back pain without apparent trauma. This report presents the clinical outcome of a 75-year-old female with SIF, and an underlying medical history of osteoporosis and rheumatoid arthritis. She was treated non-operatively, in-hospital, with Korean medicine. Patient progress was assessed using the numerical rating scale and self-reported symptoms. Post-treatment, the numerical rating scale score for pain in her hip decreased from 7 to 2. At admission, the patient was unable to sit, and could only walk 3 m with assistance. At discharge, she could sit for longer than 1 hour and walk further than 200 m unassisted. On the follow-up visit, the patient was asymptomatic, and x-ray scans showed ossification of the sacral and pubic fractures. These results suggest that, Korean medicine can effectively reduce pain and aid rehabilitation in patients with SIF, without the need for surgery.

• 대한족부족관절학회지
• /
• 제22권2호
• /
• pp.74-77
• /
• 2018

Calcaneal apophysitis is a relatively common disease in young athletes. On the other hand, if not treated properly, it can lead to apophyseal avulsion fracture in rare cases. In the case of apophyseal avulsion fractures, it is often necessary to remove or preserve the bone fragment, which often requires a suture of the Achilles tendon. A 10-year-old badminton athlete visited the outpatients' clinic with pain in both heels from 10 months ago without any trauma history. After conservative therapy, the pain in the left heel was relived but the right heel pain persisted. After 10 months of conservative therapy, the patient visited the outpatients' clinic showing a calcaneal apophyseal avulsion fracture with a total rupture of the Achilles tendon. In the operation room, a bone fragment needed to be removed because of its poor viability and the fragment was too thin for fixation. After removing the bone fragment, the ruptured Achilles tendon was fixed with an anchor system.

• Journal of Korean Neurosurgical Society
• /
• 제46권5호
• /
• pp.451-458
• /
• 2009

Objective : The purpose of this study was to analyze risk factors that are associated with intracranial lesion, and to propose criteria for classification of mild head injury (MHI), and appropriate treatment guidelines. Methods : The study was based on 898 patients who were admitted to our hospital with Glasgow Coma Scale (GCS) score of 13 to 15 between 2003 and 2007. The patients' initial computerized tomography (CT) findings were reviewed and clinical findings that were associated with intracranial lesions were analyzed. Results : GCS score, loss of consciousness (LOC), age and skull fracture were identified as independent risk factors for intracranial lesions. Based on the data ana lysed in this study, MHI patients were divided into four subgroups : very low risk MHI patients are those with a GCS score of 15 and without a history of LOC or headache; low risk MHI patients have a GCS score of 15 and with LOC and/or headache; medium risk MHI patients are those with a GCS score of 15 and with a skull fracture, neurological deficits or with one or more of the risk factors; high risk MHI patients are those with a GCS score of 15 with abnormal CT findings and GCS score of 14 and 13. Conclusion : A more detailed classification of MHI based on brain CT scan findings and clinical risk factors can potentially improve patient diagnosis. In light of our findings, high risk MHI patients should be admitted and treated in same manner as those with moderate head injury.

• Journal of Chest Surgery
• /
• 제31권2호
• /
• pp.190-193
• /
• 1998

본 강북삼성병원 흉부외과에서는 병적골절이 동반된 원발성 흉골결핵을 치험 하였다. 22세된 여자환자가 특별한 외상이없이 발생한 흉골부위의 통증 및 골절로 입원 하였다. 입원당시 시행한 흉부단순촬영 및 전산화단층촬영상 흉골의 괴사소견과 연부조직의 부종이 관찰되었다. 세침세포검사상 냉농양을 동반한 결핵성 골수염으로 진단되어 술전 항결핵 치료후 수술을 시행하였다. 수술시 흉골중앙부위의 골괴사 및 다발성 누공을 확인하였으며, 골괴사 부위를 제거한후 환자의 장골능을 골이식 하였다. 병리조직학적 결과는 결핵성 골수염의 소견 및 치즈양괴사를 보였다. 술후 경과는 양호 하였으며, 2개월동안의 추적검사상 흉골의 불안정은 관찰되지 않았다.