• Journal of Korean Foot and Ankle Society
• /
• v.25 no.3
• /
• pp.141-144
• /
• 2021

More than 120 surgical methods for the correction of hallux valgus deformities have been reported. For the correction of moderate to severe hallux valgus deformities with aesthetic demands, minimally invasive surgery at the proximal area can be considered. This paper reports a case of moderate hallux valgus deformity treated by a minimally invasive proximal transverse metatarsal osteotomy followed by intramedullary plate fixation.

• Journal of Radiation Protection and Research
• /
• v.30 no.1
• /
• pp.1-7
• /
• 2005

Radiation absorption parameters of carbon fiber panel were measured in comparison to acrylic panel. $30{\times}30cm$ sized 2mm thick carbon fiber panel and identical sized 6mm thick acrylic panel were placed in tray holder position and 0cm, 5cm, 10cm from surface of phantom. Radiation field size was $10{\times}10cm$. 50MU of 4MV photon was irradiated to the phantom with dose rate of 300MU/min. Source-to-phantom distance was 120cm. Radiation dose was measured with 0.6cc Farmer-type ionization chamber with 1cm build-up. Measurement was repeated thrice and normalization was done to the dose of the open field. Radiation transmission rate of carbon fiber panel is approximately 1% lower than acrylic panel of equivalent thickness. However, considering the strength of the material, transmission rate is higher for carbon fiber panel. Although carbon fiber panel increases the radiation dose when attached to the surface for about 2%, it normalizes the radiation dose to 97-99% of irradiated dose which could have been lowered to as much as 5-7.5% with acrylic panel. As carbon fiber panel is stronger than acrylic panel, radiation fixation device could be made thinner and thus lighter and furthermore, with increased radiation transmission. This in turn makes carbon fiber more ideal material for radiation fixation device over conventionally used acrylic.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.25 no.2
• /
• pp.1-7
• /
• 2021

The concrete deck slab at the continuous span support of the steel box girder bridge is a structure that is combined with the upper flange. It is a structure that can cause tension cracks in the deck slab at the support causing problems such as durability degradation in long span bridges. This is because the tensile stress in the longitudinal direction of the slab exceeds the design tensile strength due to the effects of dead load and live load when applying a long span. Accordingly, it is necessary to control tensile cracking by adding a reinforcing bar in the axial direction to the slab at the support and to introduce additional compressive stress. To solve this problem, a structural system of a steel box girder bridge was proposed that introduces compressive stress as PS steel wire tension in the tensile stress section of the upper slab in the continuous support. The resulting structural performance was compared and verified through the finite element analysis and the steel wire tension test of the actual specimen. By introducing compressive stress that can control the tensile stress and cracking of the slab generated in the negative moment through the tension of the PS steel wire, it is possible to improve structural safety and strengthen durability compared to the existing steel box girder bridge.

• Journal of Korean Society of Steel Construction
• /
• v.20 no.1
• /
• pp.183-193
• /
• 2008

The reliability analysis of simply-supported and continuous composite plate girder and box girder bridges under flexure was performed to provide a basic data for the development of LRFD c ode. The bridges were designed based on LRFD specification with newly proposed design live load which was developed by analyzing traffic statistics from highways and local roads. A performance function for flexural failure was expressed as a function of the flexural resistance of composite section and the design moments due to permanent load and live load. For the flexural resistance, the statistical parameters obtained by analyzing over 16,000 domestic structural steel samples were used. Several different values of bias factors for the live load moment from 1.0 to 1.2 were used. Due to the lack of available domestic measured data on the moment by permanent loads, the same statistical properties used in the calibration of ASHTO-LRFD were ap plied. The reliability indices for the composite girder bridges with various span lengths, different live load factors, and bias fact or for the live load were obtained by applying the Rackwitz-Fiessler technique.

• Journal of Korean Foot and Ankle Society
• /
• v.23 no.3
• /
• pp.135-138
• /
• 2019

According to a recent systemic review, hallux valgus deformity has a prevalence rate of about 23% among adults aged 18 to 65 years. To date, more than 100 operative methods have been reported for the correction of hallux valgus deformity. For young female with mild to moderate hallux valgus deformity, minimally invasive surgery can be considered for aesthetic demands. Here, we report a case of a young female patient with mild hallux valgus deformity treated by minimally invasive surgery using intramedullary low profile plate fixation. This can be the favorable method for secure fixation of the osteotomy site and prevention of medial skin irritation symptoms derived from a sharp osteotomy margin.

• Journal of Korean Foot and Ankle Society
• /
• v.12 no.1
• /
• pp.80-85
• /
• 2008

Purpose: To evaluate and compare the outcome between interlocking IM nailing and LCP fixation in the treatment of distal metaphyseal tibial fracture. Materials and Methods: From January 2000 to December 2007, 17 patient were treated by interlocking IM nail and 13 patient were treated by LCP fixation for distal metaphyseal tibial fracture. Results: According to AO classification, there were 2 type A1 fracture (12%), 6 type A2 fracture (36%), 3 type A3 fracture (18%), 4 type B1 fracture (24%), 1 type B3 fracture (6%), 1 type C1 fracture (6%) in interlocking IM nailing group and 1 type A2 fracture (7.7%), 2 type A3 fracture (15.4%), 3 type B1 fracture (23%), 3 type B2 fracture (23%), 3 type C1 fracture (23%), 1 type C2 fracture (7.7%) in LCP fixation group. The clinical functional outcome (according to AOFAS score) is 75.6 point in IM nailing group and 81.5 point in LCP fixation group. In IM nailing group, 65% of patient showed satisfactory result and In LCP fixation group, 77% of patient showed satisfactory result. Conclusion: There is no difference on clinical results between IM nailing and MIPPO (minimal invasive percutaneous plate osteosynthesis) group in the treatment of distal tibia fracture. But MIPPO group have higher subjective satisfactory score and less complication rate. The weakness of our study is a small case number and limited follow-up and we believe a better designed prospective study will be needed.

• Radiation Oncology Journal
• /
• v.4 no.2
• /
• pp.165-172
• /
• 1986

In electron therapy, lead cutout or low-melting alloy block is used for shaping the field. Material for shaping electron field affects the output factor as wet 1 as the collimation system. The authors measured the output factors of electron beams for shaped fields from Clinac-18 using ionization chamber of Farmer type in polystyrene phantom. They analyzed the parameters that affect the output factors. The output factors of electron beams depend on the incident energy, collimation system and size of shaped field. For shaped field the variation of output factor for the field size (A/P) has appearence of a smooth curve for all energy and all applicator collimator combination. The output factors for open field deviate from the curves for shaped fields. An output factor for a given field can be calculated by equivalent field method such as A/P method, if a combination of applicator and collimator is fixed.

• Journal of Korean Society of Steel Construction
• /
• v.21 no.5
• /
• pp.527-536
• /
• 2009

The purpose of this experimental study was to investigate the block shear fracture behavior and curling effect on a single shear-bolted connection in thin-walled carbon steel fabricated with four bolts. The specimens that fail by block shear were planned to have a constant dimension of the edge distance perpendicular to the loading direction, bolt diameter, pitch, and gage. The main variables of the specimens were plate thickness and end distance parallel to the loading direction. A monotonic tensile test was carried out for the bolted connections, and the ultimate behaviors, such as the fracture shape, ultimate strength, and curling, were compared with those that had been predicted using the current design specifications. The conditions of curling occurrence in terms of plate thickness and end distance were also investigated, and the strength reduction due to curling was considered.

• Archives of design research
• /
• v.14 no.1
• /
• pp.53-62
• /
• 2001

Thanks to advanced development of industrial technology, various kinds of the rapidly changing instruments are affecting our life deeply. So, just a few years are enough to regard yesterday's products as old ones due to the newly invented industrial products. Likewise, the blackboards that we face with in our actual life have been developed as completely new ones of new conception for new equipment and environmental harmony, which is completely different from the typical ones. Height-Control and Open-Shut blackboard with notice board can be adjusted to a lecturer's height, the central pan of main blackboard being controlled up and down. During writing on the board, lecturers can fix the board to their convenient position, and after writing, they can fix the height of the board to the students, convenient position. Therefore, students do not have to move their bodies left and right, or up and down, because of the lecture tables or people in front of them. The newly developed blackboard removed such an inconvenience and is suitable for today's new educational environment. In the both sides of the blackboard, general notice boards are attached to the surface, while the supplementary blackboards are fixed to inside so that they can be drawn when necessary. Considering new environments of the blackboards equipped with these diverse functions, we would like to offer the design procedure about the blackboard frames and chalk store boxes and its results.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.26 no.5
• /
• pp.542-550
• /
• 2020

The use of high-strength aluminum alloys for ships and of shore structures has many benefits compared to carbon steels. Recently, high-strength aluminum alloys have been widely used in onshore and of shore industries, and they are widely used for the side shell structures of special-purpose ships. Their use in box girders of bridge structures and in the topside of fixed platforms is also becoming more widespread. Use of aluminum material can reduce fuel consumption by reducing the weight of the composite material through a weight composition ratio of 1/3 compared to carbon steel. The characteristics of the stress strain relationship of an aluminum structure are quite different from those of a steel structure, because of the influence of the welding[process heat affected zone (HAZ). The HAZ of aluminum is much wider than that of steel owing to its higher heat conductivity. In this study, by considering the HAZ generated by metal insert gas (MIG) welding, the buckling and final strength characteristics of an aluminum reinforcing plate against longitudinal compression loads were analyzed. MIG welding reduces both the buckling and ultimate strength, and the energy dissipation rate after initial yielding is high in the range of the HAZ being 15 mm, and then the difference is small when HAZ being 25 mm or more. Therefore, it is important to review and analyze the influence of the HAZ to estimate the structural behavior of the stiffened plate to which the aluminum alloy material is applied.