• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.267-273
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• 2003

Steel fiber may be used to raise the effectiveness and safety of reinforced concrete structure and to relax its brittle-fracture behavior. However it is to be clearly stated that the uncertainty for the strength of fiber reinforced concrete(SFRC) is rather increased. Therefore, it is necessary to evaluate the safety of SFRC beam using reliability analysis incorporating realistic uncertainty. This study presents the statistical data and proposes the limit state model to analyze the reliability of SFRC bear In order to verify the efficiency of the proposed limit state model, its numerical application and sensitivity analysis were performed for a continuous SFRC beam. From the results of the numerical analysis, it is founded that the reliability of SFRC beam is significantly difficult from the conventional RC beams and proposed limit state model (or SFRC beam is more rational compared with that for conventional RC beams. Then it may be stated that the reliability analysis of SFRC beams must be carried out for the development of design criteria and the safety assessment.

• Structural Engineering and Mechanics
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• 제19권5호
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• pp.567-580
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• 2005

Numerous tests on concrete structure members under local pressure demonstrated that the compressive strength of concrete at the loaded surface is increased by the confinement effect provided by the enveloping concrete. Even though most design codes propose specific criteria for preventing bearing failure, they do not take into consideration size effect which is an important phenomenon in the fracture mechanics of concrete/reinforced concrete. In this paper, six series of square prism concrete blocks with three different depths (size range = 1:4) and two different height/depth ratios of 2 and 3 are tested under concentrated load. Ultimate loads obtained from the test results are analysed by means of the modified size effect law (MSEL). Then, a prediction formula, which considers effect of both depth and height on size effect, is proposed. The developed formula is compared with experimental data existing in the literature. It is concluded that the observed size effect is in good agreement with the MSEL.

• Structural Engineering and Mechanics
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• 제58권4호
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• pp.707-718
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• 2016

The main objective of the present paper is to investigate, by means of a boundary value problem permitting a semi-analytic solution, qualitative behaviour of solutions for two pressure-dependent yield criteria used for plastically incompressible polymers. The study mainly focuses on the regime of friction (sticking and sliding). It is shown that the existence of the solution satisfying the regime of sticking depends on other boundary conditions. In particular, there is such a class of boundary conditions depending on the yield criterion adopted that the regime of sliding is required for the existence of the solution independently of the friction law.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1996년도 춘계학술발표회논문집(1)
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• pp.291-295
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• 1996

In CANDU reactor, each pressure tubes contain twelve fuel bundles and provide the inlet and outlet for the primary coolant. If a leak develops in the pressure tube, it is detected by Annulus Gas System which contains circulating dry $CO_2$ gas. Since the leaks caused by the flaws are resulted in pressure tube break, establishment of flaw assessment method is very significant in view of the fracture mechanics. In this paper, various criteria for assessing the flaws are presented to prevent the tube rupture and ensure the integrity of reactor operating.

• Steel and Composite Structures
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• 제25권2호
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• pp.209-216
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• 2017

In this paper, the analysis of the behavior of surface cracks in finite-thickness plates repaired with a Boron/Epoxy composite patch is investigated using three-dimensional finite element methods. The stress intensity factor at the crack-front was used as the fracture criteria. Using the Ansys Parametric Design Language (APDL), the stress intensities at the internal and external positions of repaired surface crack were compared. The effects of the mechanical and geometrical properties of the adhesive layer and the composite patch on the variation of the stress intensity factor at the crack-front were examined.

• 한국지진공학회논문집
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• 제7권3호
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• pp.69-77
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• 2003

본 연구는 8개의 RBS(reduced beam section) 내진 철골모멘트접합부의 실물대 실험결과를 요약한 것이다. 실험의 주요변수는 보 웨브 접합법 및 패널존 강도를 택하였다. 균형 패널존 시험체는 접합부의 내진성능을 감소시키지 않으면서, 보와 패널존이 함께 균형적으로 지진에너지를 소산시키도록 설계하여 값비싼 패널존 보강판(doubler plates)의 수요를 줄이고자 시도한 것이다. 보 웨브를 용접한 시험제는 모두 특별 연성모멘트골조에서 요구되는 접합부 회전능력을 충분히 발휘하였다. 반면 보 웨브를 볼트 접합한 시험체는 조기에 스캘럽을 가로지르는 취성파단이 발생하는 열등한 성능을 보였다. 보 그루브 용접부 자체의 취성파괴가 본 연구에서와 같이 양질의 용접에 의해 방지되면, 스켈럽 부근의 취성파단이 다음에 해결해야 할 문제로 대두되는 경향을 보인다. 보 웨브를 볼팅한 경우에 접합부 취성파단의 빈도가 월등히 높은 이유를 실험 및 해석결과를 토대로 제시하였다. 측정된 변형도 데이터에 의할 때, 접합부의 전단력 전달메카니즘은 흔히 가정하는 고전 휨이론에 의한 예측과 전혀 다르다. 이는 전통적 보 웨브 설계법을 재검토할 필요가 있음을 시사하는 것이다. 아울러, 접합부에서 요구되는 바람직한 거동기준을 제시하고 이를 근거로 균형 패널존의 강도범위에 대한 예비적 추정치를 제시하였다.

• Journal of Korean Neurosurgical Society
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• 제29권5호
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• pp.668-674
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• 2000

Objective : The classic and accepted surgical method of compound comminuted depressed skull fractures (FCCD) involves total resection of all the contaminated bone and fragments at the fracture site. A second operation for cranioplasty is then performed at a later date. However, we have believed that primary repair of these bony defects can be achieved by the replacement of bone fragments at the time of the initial debridement, and this can be accomplished without danger to patient. The authors retrospectively reviewed the surgical results to assess the advantages and disadvantages, and also propose the selection criteria of replacement of fractured bone fragments as a primary procedure in FCCD. Materials and Methods : The authors analyzed the data extracted from medical records, and radiological findings in 22 of 71 patients with FCCD, who underwent immediate replacement of fractured bone fragments between April 1993 and October 1998. The mean follow-up period was 13.7 months. The selection criteria for the operation included the patients with mild to moderate severity, regardless of the degree of contamination or dural violation, which presented in hospital within 24 hours of injury. Results : The ages of the patients varied from 4 to 63 years, and there were 20 males and 2 females. Seventeen of 22 patients were fully conscious on admission and the others also had relatively good Glasgow coma scales. Sixteen fractures were located in the frontal area, 9 with involvement of the frontal sinuses, and 6 in the parietal and temporoparietal areas. Of the 22 patients, 8(36.3%) had dural lacerations with 3 of these requiring patching with pericranium, and 12(54.5%) had intracranial hematoma requiring wide craniotomy. The degree of wound contamination was also variable. Fifteen patients had relatively clean wounds, while seven(31.8%) had seriously contaminated wounds with soil, sand, hair, and wood. Only one patient(4.5%) developed infection, and the bone fragments were removed. All wounds healed primarily without pulsatile defect, the skull has remained solid, and no complications have occurred, except the infected case. Conclusion : It is proposed that bone fragments removal for FCCD, regardless of the degree of contamination or dural violation, is not necessary and that primary bone fragments replacement avoids a second operation for cranioplasty.

• 대한족부족관절학회지
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• 제17권2호
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• pp.106-114
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• 2013

Purpose: Posteroanterior screw fixation is biomechanically stronger than anteroposterior screw fixation. However, there are few literature about the correlation between clinical results and more strength by posteroanterior fixation. This study was performed to evaluate the clinical outcomes of the accelerated rehabilitation following anterior open reduction and posterior percutaneous screw fixation for displaced talar neck fractures. Materials and Methods: Eighteen cases were followed up for more than 1 year after posteroanterior fixation using headless compression screw for talar neck fractures. The clinical evaluation was performed according to American Orthopaedic Foot and Ankle Society (AOFAS) score and Hawkins criteria. As radiographic evaluation, the degree of fracture displacement, period to union, and occurrence rate of complications such as avascular necrosis through MRI were measured. Results: The AOFAS score was average 90.4 points at the last follow-up. There were 7 excellent, 9 good, and 2 fair results according to the Hawkins criteria. Therefore, 16 cases(88.8%) achieved satisfactory results. The degree of fracture displacement had improved significantly from preoperative average 5.6 mm to 1.2 mm immediate postoperatively, and maintained to 1.1mm at the last follow-up. All cases achieved bone union, and the period to union was average 12.4 weeks. There were 3 cases of avascular necrosis of talar body and 2 cases of post-traumatic arthritis. Conclusion: Anterior open reduction and posterior percutaneous headless screw fixation seems to be an effective surgical method for displaced talar neck fractures, because of the possibility of accurate restoration of articular surface, fixation strength enough to early rehabilitation, and needlessness of hardware removal.

• 대한정형외과스포츠의학회지
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• 제4권2호
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• pp.116-121
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• 2005

목적: 상완골 소두 골절은 매우 희귀한 골절의 형태인데 관절면의 침범으로 인해 적극적인 수술적 치료가 요한다. 이러한 상완골 소두 골절의 관혈적 정복 후 내고정 후의 결과를 보고하는 바이다. 대상 및 방법: 1998년부터 2004년 까지 상완골 소두 골절로 수술 시행받은 4명의 환자를 대상으로 하였다. Morrey의 분류법 상 제 1형이 3례, 제 3형이 1례였다. 전 례에서 주관절의 외측 도달법을 사용하였으며, 관혈적 정복후 유관 나사못 고정을 실시하였다. 수술후 주관절의 부목등의 고정은 4일에서 28일 까지 소요되었다. 최종 추시 판정 시 Mayor의 주관절 기능 평가 방법을 이용하여 주관절 운동 범위, 주관절의 안정성, 동통 유무 등을 평가하였다. 결과: 평균 추시기간은 12개월에서 36개월이었으며 평균 15개월(12개월-36개월) 이었다. 3례의 경우 견고한 골고정을 얻었으며 우수한 관절 운동범위를 얻을 수 있었다. 그러나 만성 소두골 골절 및 부정유합으로 내원하였던 1 례의 경우 추시 관찰동안 재활에 순응하지 않아서 40도-100도의 운동범위만을 보여주었다. 전 례에서 무혈성 괴사나 주관절 관절염의 소견은 보이지 않았다. 결론: 상완골 소두 골절은 희귀하지만 적극적으로 관혈적 정복 및 내고정시 우수한 결과를 보여 줄 수 있었다.

• 대한간호학회지
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• 제45권2호
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• pp.293-305
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• 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.