• Steel and Composite Structures
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• v.47 no.1
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• pp.121-134
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• 2023

This paper tested 11 concrete-encased concrete-filled steel tube (CFST) composite columns and one reinforced concrete column under combined axial compression and lateral loads. The primary parameters, including the loading system, axial compression ratio, volume stirrup ratio, diameter-to-thickness ratio of the steel tube, and stirrup form, were varied. The influence of the parameters on the failure mode, strength, ductility, energy dissipation, strength degradation, and damage evolution of the composite columns were revealed. Moreover, a two-parameter nonlinear seismic damage model for composite columns was established, which can reflect the degree and development process of the seismic damage. In addition, the relationships among the inter-story drift ratio, damage index and seismic performance level of composite columns were established to provide a theoretical basis for seismic performance design and damage assessments.

• Journal of Korean Foot and Ankle Society
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• v.23 no.4
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• pp.189-195
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• 2019

Purpose: The aim of this study is to evaluate if the Ilizarov external fixation procedure with axial compression can help to obtain fusion across the ankle joint in patients with a high risk of nonunion. Materials and Methods: From January 2006 to December 2015, the study reviewed 17 patients who underwent ankle arthropathy with a high risk of nonunion and who underwent ankle fusion using the Ilizarov external fixator with axial compression and auto bone grafting. After the lateral surface of the ankle joint was exposed through a lateral trans-fibular approach, massive removal of the articular cartilage and excision of any loose or avascular bone were done. With the cortical bone harvested from the pelvis as corticocancellous bone blocks, we inserted the two cortical blocks longitudinally into the anterior and posterior part of the free ankle space from lateral to medial to make the rectangular chamber to fill the cancellous bones. After the Ilizarov external fixator was equipped, we tightened the frame by 5 mm to compress the bone graft space. We accessed the American Orthopaedic Foot and Ankle Society (AOFAS) AnkleHindfoot score both preoperatively and postoperatively. Results: The average age at the time of operation was 63.4 years (range, 47~78 years). The mean frame time was 17.4 weeks (range, 15~23 weeks). The average follow-up period was 3.7 years (range, 2~6 years). Osseous fusion was obtained in 15 patients (88.2%). There were two stable pseudarthroses among the rheumatoid arthritis patients, and we continued their follow-up. The mean AOFAS AnkleHindfoot score improved from 48.5 to 73.7 points. Conclusion: Ankle arthrodesis using the Ilizarov external fixation with axial compression and auto bone grafting on the ankle arthropathy that had difficult conditions to achieve union is considered one of the useful methods with a correspondingly low incidence of complications.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2003.10a
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• pp.367-370
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• 2003

In this study, application of SAM (self-assembled monolayer) to nano replication process as an anti-adhesion layer was presented to reduce the surface energy between the nano mold and the replicated polymeric nano patterns. The electron beam lithography was used for master nano patterns and the electorforming process was used to fabricate the nickel nano stamper. Alkanethiol SAM as an anti-adhesion layer was deposited on metallic nano stamper using solution deposition method. To analyze wettability and adhesion force of SAM, contact angle and LFM (Lateral Force Microscopy) were measured at the actual processing temperature and pressure for the case of nano compression molding and at the actual UV dose for the case of nano UV molding. It was found that the surface energy due to SAM deposition on the nickel nano stamper markedly decreased and the quality of SAM on the nickel stamper maintained under the actual molding environments.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.3
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• pp.34-44
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• 1998

It is clear that when an automobile negotiates a curve the lateral acceleration causes an increase in tire normal load for the wheels on the outside of the curve and a decrease in load for the inside wheels. However, just how the details of the suspension linkages and the parameters of the springs and shock absorbers affect the dynamics of the load transfer os not easily understood. One even encounters the false idea that since it is the compression and extension of the main suspension springs spring body role which largely determines the changes in normal load, of roll could be reduced, the load transfer would also be reduced. Using free body diagrams, one can explain quite clearly how the load is transferred for steady state cornering, and, using complex multibody models of particular vehicles one can simulate in good fidelity how load transfer occurs dynamically. Here we adopt a middle ground by using the concept of roll center and using a series of half-car bond graph models to point out main effects. Since bond graph junction structures automatically and consistently constrain geometric and force variables simultaneously, they can be used to point out hidden assumptions of other simplified vehicle models.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.04a
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• pp.107-112
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• 1993

The objective of this experimental investigation is to examine the feasibility and the usefulness of the complementary crosstie in the current ACI 318-89 code for rienforced concrete columns subjected to constant axial load and lateral load reversals. Tests were conducted on1/3 scaled four columns with the length of 1.9m and the cross section of 20$\times$20 cm. The main parameters of specimens were the magnitude of axial load applied and the configuration of transverse reinforcements . From the experimental results, it can be seen that while the column subjected to lower axial load represented considerable ductility behaviors, the column subjected to higher axial load showed the brittle failure

• Structural Engineering and Mechanics
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• v.46 no.1
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• pp.111-135
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• 2013

An experimental study has been carried out on square plain concrete (PC) and reinforced concrete (RC) columns strengthened with carbon fiber-reinforced polymer (CFRP) sheets. A total of 78 specimens were loaded to failure in axial compression and investigated in both axial and transverse directions. Slenderness of the columns, number of wrap layers and concrete strength were the test parameters. Compressive stress, axial and hoop strains were recorded to evaluate the stress-strain relationship, ultimate strength and ductility of the specimens. Results clearly demonstrate that composite wrapping can enhance the structural performance of square columns in terms of both maximum strength and ductility. On the basis of the effective lateral confining pressure of composite jacket and the effective FRP strain coefficient, new peak stress equations were proposed to predict the axial strength and corresponding strain of FRP-confined square concrete columns. This model incorporates the effect of the effective circumferential FRP failure strain and the effect of the effective lateral confining pressure. The results show that the predictions of the model agree well with the test data.

• The Korean Journal of Pain
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• v.31 no.3
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• pp.215-220
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• 2018

Meralgia paresthetica (MP) is a sensory mononeuropathy, caused by compression of the lateral femoral cutaneous nerve (LFCN) of thigh. Patients refractory to conservative management are treated with various interventional procedures. We report the first use of extended duration (8 minutes) pulsed radiofrequency of the LFCN in a case series of five patients with refractory MP. Four patients had follow up for 1-2 years, and one had 6 months follow up. All patients reported remarkable and long lasting symptom relief and an increase in daily life activities. Three patients came off medications and two patients required minimal doses of neuropathic medications. No complications were observed.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.495-500
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• 2003

The effect of initial combined load on the lateral free vibration of arches is investigated. For the analysis, P-M interaction curves for the arches are obtained. The arches are circular arches which have constant cross-section and simply supported. Also, the arches are subjected both radial uniform distributed load which results in an axial compression on the cross-section and end moments that cause uniform bending action at the same time. All analysis are performed by finite element method based on Kang and Yoo's curved beam theory.

• Journal of the Earthquake Engineering Society of Korea
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• v.21 no.1
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• pp.21-29
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• 2017

Purpose of this study is to investigate structural behavior of the rectangular hollow column with various transverse reinforcement details. Experimental variables are diameter, arrangement details and lateral spacing of cross tie. A total of 66 column specimens have been prepared and tested under axial compressive load. Test results showed that behaviors of column specimens were different depending on the cross tie details. Specimens with cross tie wrapping longitudinal steel and transverse steel have greater strength and ductility than specimens with cross tie wrapping the longitudinal steel.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.565-570
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• 2000

The objective of this paper is to analyse the high-strength concrete columns subjected to reversed cyclic and axial loads by using nonlinear analysis model and compare the experimental results with analysis. The analytical parameters are the compressive strength of concrete, spacing of lateral reinforcement and lateral reinforcement ratio. In this study, the proposed analytical model takes ito account the influence of confined concrete, tension stiffening and strain hardening of steel. The high-strength concrete columns are used to model fiber section element. The analysis results are shown comparatively good prediction on envelope curve, accumulative dissipated energy, deformability and so on.