• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2007년도 정기 학술대회 논문집
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• pp.845-850
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• 2007

The empirical AISC panel zone thickness provision$(t_z\geq(d_z+w_z)$/90) to prevent the cyclic shear buckling of the panel zone was proposed based on the test data of Krawinkler et al. (1971) and Bertero et al. (1973) However, no published records of the equation development or any other background information appear to be available. The calibrated finite element analysis results of this study indicated that the AISC provision was not reasonable. In this study, through including the effects of the column axial force and the aspect ratio of the panel zone, a new equation for the relative strength between the beam and the panel zone was proposed such that the proposed equation can prevent the panel zone shear buckling and reduce the potential fracture associated with the kinking of the column flanges.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2001년도 춘계학술대회 논문집
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• pp.230-237
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• 2001

For the structural integrity of large and complex structures such as railway vehicle, the in-field diagnosis of mechanical properties of the structures is needed, and especially, the mechanical characteristics of the weldment must be carefully evaluated. But, conventional standard testing methods having destructive procedures are not applicable to in-field assessment of mechanical property variations within weldment because they needs the limitations of specimen size and geometry. In this paper, to overcome this problems, the advanced indentation technique (AIS) is introduced for simple and non-destructive/in-field testing of weldment of industrial structures. This test measures indentation load-depth curve during indentation and analyzes the mechanical properties related to deformation and fracture. First of all, flow properties such as yield strength, tensile strength and work hardening index can be evaluated through the analysis of the deformation behavior beneath the spherical indenter. Additionally, case studies of advanced indentation techniques are introduced.

• Structural Engineering and Mechanics
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• 제56권6호
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• pp.1003-1020
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• 2015

In this study, free vibration analysis of an edge cracked multilayered symmetric sandwich beams made of functionally graded materials are investigated. Modelling of the cracked structure is based on the linear elastic fracture mechanics theory. Material properties of the functionally graded beams change in the thickness direction according to the power and exponential laws. To represent functionally graded symmetric sandwich beams more realistic, fifty layered beam is considered. Composition of each layer is different although each layer is isotropic and homogeneous. The considered problem is carried out within the Timoshenko first order shear deformation beam theory by using finite element method. A MATLAB code developed to calculate natural frequencies for clamped and simply supported conditions. The obtained results are compared with published studies and excellent agreement is observed. In the study, the effects of crack location, depth of the crack, power law index and slenderness ratio on the natural frequencies are investigated.

• Journal of Chest Surgery
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• 제23권3호
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• pp.588-593
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• 1990

The rupture of tracheobronchial tree caused by non penetrating blunt trauma is being increased in incidence though it is still rarely occurred on now Because this type of injury is uncommon, a high index of suspicion should be maintained in all crush injuries involving the chest. Early diagnosis and primary repair not only restore normal lung function but also avoid the difficulties and complications associated with delayed diagnosis and repair. We experienced a case of tracheobronchial rupture caused by non penetrating blunt chest trauma without rib fracture. The patient was a 16 year old male who was a high school student. He was compressed on anterior chest by hand ball goal post being failed down on the morning of admission day. After this accident, he was suffered from progressively developing dyspnea and subcutaneous emphysema on face, neck and anterior chest. The diagnosis, tracheal rupture, was made by chest CT and bronchoscopy. After right thoracotomy, the ruptured site was directly closed by using interrupted suture. Post-operative course was uneventful. Thus we report this case of traumatic tracheal rupture with review of literature.

• 한국정밀공학회지
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• 제14권11호
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• pp.50-57
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• 1997

In order to make unmanned machining systems with satisfactory performances, it is necessary to incorporate appropriate condition monitoring systems in the machining workstations to provide the required intelligence of the expert. This paper deals with condition monitoring for chatter, tool wear and breakage during turning operation. To develop economic sensing and identiffication methods for turning processes, sound pressure measurement and digital signal processing technique were proposed. We suppressed chatter by stability control methodology, which was studied through manipulation of spindle speeds regarding to chatter frequencies. It was shown that tool wear and fracture were identified and to be estimated by using the wear indices. The validity of the proposed system was confirmed through the large number of cutting tests.

• 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.

• 한국압력기기공학회 논문집
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• 제10권1호
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• pp.100-106
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• 2014

There is a growing need to introduce advanced pressure vessel steels with higher strength and toughness for the optimizatiooCn of the design and construction of longer life and larger capacity nuclear power plants. SA508 Gr.4N Ni-Cr-Mo low alloy steels have superior strength and fracture toughness, compared to SA508 Gr.3 Mn-Mo-Ni low alloy steel. Therefore, the application of SA508 Gr.4N low alloy steel could be considered to satisfy the strength and toughness required in advanced nuclear power plants. The purpose of this study is to characterize the microstructure and mechanical properties of SA508 Gr.4N low alloy steels. 1 ton ingot of SA508 Gr.4N model alloy was fabricated by vacuum induction melting followed by forging, quenching, and tempering. The predominant microstructure of the SA508 Gr.4N model alloy is tempered martensite having small packet and fine Cr-rich carbides. The yield strength at room temperature was 540MPa, and it was decreased with an increase of test temperature while DSA phenomenon occurred at around $288^{\circ}C$. Overall transition property of SA508 Gr.4N model alloy was much better than SA508 Gr.3 low alloy steel. The index temperature, $T_{41J}$, of SA508 Gr.4N model alloy was $-132^{\circ}C$ in Charpy impact tests, and reference nil-ductility transition temperature, $RT_{NDT}$ of $-105^{\circ}C$ was obtained from drop weight tests. From the fracture toughness tests performed in accordance with the ASTM standard E1921 Master curve method, the reference temperature, $T_0$ was $-147^{\circ}C$, which was improved more than $60^{\circ}C$ compared to SA508 Gr.3 low alloy steels.

• Journal of Korean Neurosurgical Society
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• 제53권1호
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• pp.6-12
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• 2013

Objective : This consecutive retrospective study was designed to analyze and to compare the efficacy and outcomes of anterior cervical discectomy and fusion (ACDF) using a fibular and femur allograft with anterior cervical plating. Methods : A total of 88 consecutive patients suffering from cervical degenerative disc disease (DDD) who were treated with ACDF from September 2007 to August 2010 were enrolled in this study. Thirty-seven patients (58 segments) underwent anterior interbody fusion with a femur allograft, and 51 patients (64 segments) were treated with a fibular allograft. The mean follow-up period was 16.0 (range, 12-25) months in the femur group and 19.5 (range, 14-39) months in the fibular group. Cage fracture and breakage, subsidence rate, fusion rate, segmental angle and height and disc height were assessed by using radiography. Clinical outcomes were assessed using a visual analog scale and neck disability index. Results : At 12 months postoperatively, cage fracture and breakage had occurred in 3.4% (2/58) and 7.4% (4/58) of the patients in the femur group, respectively, and 21.9% (14/64) and 31.3% (20/64) of the patients in the fibular group, respectively (p<0.05). Subsidence was noted in 43.1% (25/58) of the femur group and in 50.5% (32/64) of the fibular group. No difference in improvements in the clinical outcome between the two groups was observed. Conclusion : The femur allograft showed good results in subsidence and radiologic parameters, and sustained the original cage shape more effectively than the fibular allograft. The present study suggests that the femur allograft may be a good choice as a fusion substitute for the treatment of cervical DDD.

• Clinics in Shoulder and Elbow
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• 제20권1호
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• pp.18-23
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• 2017

Background: To assess the incidence of venous thromboembolism (VTE) following shoulder surgery and to evaluate the role of postoperative duplex ultrasonography. Methods: The study comprised a total of 224 patients who underwent shoulder surgery, including 180 shoulder arthroscopic surgeries, 28 shoulder arthroplasties, and 16 plate fixations for proximal humerus fracture between January 2014 and December 2014. The mean age of patients was 59.0 years, and there were 81 men and 143 women. Clinical data, including body mass index, blood tests, metabolic work-up for liver and renal function, previous, and present medical history, were evaluated. Duplex ultrasonography in the operative arm was performed on 2 to 4 days after surgery. Results: The overall incidence of VTE following shoulder surgery was 0.45% (1/224). One patient with open reduction and plate fixation for proximal humerus fracture had asymptomatic deep vein thrombosis that showed complete remission after anticoagulant medication during a 2-month period. Four patients had asymptomatic superficial cephalic vein thrombosis and complete remission without any treatment. There was no case of pulmonary embolism. Conclusions: The incidence of VTE following shoulder surgery was extremely low in Asians. Duplex ultrasonography may be not considered a routine follow-up of shoulder surgery and can be selectively performed in high-risk or symptomatic patients for VTE.

• 대한한방내과학회지
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• 제42권5호
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• pp.1027-1034
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• 2021

Objectives: This study aimed to determine the effects of Korean medical treatment on a patient with compression fractures. Methods: The patient was treated with herbal medicine and acupuncture for 51 days. Symptom changes were measured using the Numerical Rating Scale (NRS), Range of Motion (ROM), Oswestry Disability Index (ODI), and European Quality of Life Five Dimensions (EQ-5D) Scale. Results: The NRS score for lower back pain decreased from 7 to 3, and the ODI score decreased from 51.11 to 22.22. Range of motion (ROM) increased meaningfully in flexion(from 30 to 60), Left/Right lateral bending(from 10/30 to 30/45), Left/Right rotation (from 10/30 to 30/45), and the EQ-5D score also increased from 0.506 to 0.677. Conclusion: The results indicate that Korean medical treatment may be effective for managing patients' acute compression fractures.