• Journal of Korean Foot and Ankle Society
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• v.21 no.1
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• pp.7-11
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• 2017

Purpose: We retrospectively analyzed the radiographic and clinical results after the first ray of forefoot osteotomy using low profile wedge plate without additional cancellous bone grafting for pes planus correction. Materials and Methods: Twenty-four patients were enrolled in this study. Medial cuneiform opening wedge osteotomy was performed in 12 patients (Cotton osteotomy, group C) and first metatarsal base osteotomy was performed in 12 patients (group MT). Results: On average, the wedge size was 5.61 mm (5~6 mm). The mean time to radiographic union was 3.18 and 3.27 months in groups C and MT, respectively. Postoperative talonavicular coverage angle, talo-first metatarsal angle (anteroposterior), talo-first metatarsal angle (lateral), talo-calcaneal angle (lateral), medial cuneiform height, and American orthopaedic foot, as well as ankle society midfoot scale were significantly improved in both groups. Nonunion, delayed union or fixation failure was not presented in our series. Conclusion: We have shown that low profile wedge plate was effective in the case of first ray forefoot osteotomy for pes planus correction without any additional cancellous bone grafting.

• Journal of Korean Foot and Ankle Society
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• v.17 no.4
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• pp.302-308
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• 2013

Purpose: To present clinical results of proximal first metatarsal opening wedge osteotomy and low profile plate fixation in hallux valgus deformity. Materials and Methods: Thirty-two patients (39 feet) underwent surgery for hallux valgus deformity. Fourteen patients (18 feet; Group A) underwent proximal first metatarsal opening wedge osteotomy fixed with low profile titanium plate ($Arthrex^{(R)}$), and 18 patients (21 feet; Group B) underwent proximal chevron osteotomy with two K-wires. Improvement in hallux valgus angle (HVA), 1, 2 intermetatarsal angle (IMA), range of motion of 1st metatarsophalangeal joint, VAS score, and the length of first metatarsal on weight-bearing radiograph were evaluated preoperatively and at final follow-up. Results: HVA improved from $36.2{\pm}6.6$ degrees to $11.7{\pm}5.1$ degrees, and 1, 2 IMA improved from $15.7{\pm}2.6$ degrees to $7.2{\pm}1.9$ degrees. VAS score improved from $7.2{\pm}1.2$ to $1.4{\pm}0.9$. There were no significant differences clinically and radiologically. Conclusion: Proximal first metatarsal opening wedge osteotomy with stable fixation using low profile plate may be an effective surgical option for correction of hallux valgus deformity.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.6
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• pp.76-81
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• 2021

A plastic noise barrier is a structure installed to minimize noise, and it is composed of the main plate, sound-absorbing plate, and sound-absorbing material. Plastic noise barrier structures have several advantages compared to other products, such as light weight, anticorrosion, durability, easy assembly, rapid construction, and low costs. In this study, the main and sound-absorbing plates were manufactured through extrusion molding, and the sound-absorbing plate was finished with a press to improve the conventional injection molding. Extrusion molding dies and punch dies were designed, and a profile extrusion-molding system was developed. Thus, inexpensive and efficient sound-absorbing and main plates can be produced, and the noise barrier structure can be assembled rapidly. Additionally, a noise barrier structure with extended service life and excellent quality can be constructed by creating uniform free space to accommodate increased temperatures after assembly and installation.

• Journal of IKEEE
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• v.24 no.3
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• pp.828-837
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• 2020

This paper presents the optimal design of planar flyback transformer suitable for small-size and low-profile of AC to DC adapter for 10W tablet. This paper also proposes the injection winding transformer of Hybrid and Drum types capable of the winding method of automatic type and the reduction of transformer size and leakage inductance(L_k) compared to the conventional mass-production flyback transformer with the winding method of manual type. In particular, the injection winding transformer of Drum type proposed in this paper is constructed in a horizontal laying of its transformer to solve the connection problem of copper plate injection winding on the secondary side of the one of Hybrid type. The primary and secondary windings of the injection winding transformer of Hybrid and Drum types used the conventional winding and the copper plate injection winding, respectively. For the injection winding transformer of Hybrid and Drum types proposed in this paper, the optimal design of planar flyback transformer suitable for small-size and low-profile was carried out using Maxwell 2D and 3D tool.

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

• Smart Structures and Systems
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• v.4 no.5
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• pp.565-582
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• 2008

This paper presents a feasibility study of flexible piezoelectric paint for use in wide-band low-profile surface-mount or embeddable ultrasonic sensor for in situ structural health monitoring. Piezoelectric paint is a piezoelectric composite with 0-3 connectivity. Because of its ease of application, piezoelectric paint can be readily fabricated into sensing element with complex pattern. This study examines the characteristics of piezoelectric paint in acoustic emission signal and ultrasonic guided wave sensing. A series of ultrasonic tests including pitch catch and pencil break tests were performed to validate the ultrasonic wave sensing capability of piezoelectric paint. The results of finite element simulation of ultrasonic wave propagation, and acoustic emission generated by a pencil lead break on an aluminum plate are also presented in this paper along with corresponding experimental data. Based on the preliminary experimental results, the piezoelectric paint appears to offer a promising sensing material for use in real-time monitoring of crack initiation and propagation in both metallic and composite structures.

• Journal of the Korean institute of surface engineering
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• v.45 no.4
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• pp.174-180
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• 2012

Low pressure inductively coupled plasma characteristics of argon and oxygen are numerically simulated for a 400 mm rectangular type system with a plasma fluid model. The results showed lower power absorption profile at the corner than a circular one in a 13.56 MHz driven 1.5 turn antenna system with a drift-diffusion and quasi-neutrality assumption. Ions controlled by electric field are more non-uniform than metastables and the power absorption profile of oxygen plasma is affected by horizontal gas flow pattern to show 25% lower power absorption at the pumping flange side. Oxygen negative ions which are generated in electron collisional dissociation of oxygen molecules was calculated as 0.1% of oxygen atoms with similar spatial profile.

• Journal of the Korean Solar Energy Society
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• v.30 no.6
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• pp.28-33
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• 2010

Solar collectors to be applied are mainly flat-plate or vacuum tube collector which is used for hot water supply of house because of low heat value and low temperature. There are a necessity to expand applicable scope of solar collector into the industrial process heat source and air conditioner for coping with renewable energy policy of government and industrial trend. This study is to analysis the performance of PTC solar collector of concentrating type and flat-plate of non-concentrating. For this, temperature difference and heating value as insolation of air outside is measured from these two collectors mounted on 2-axial solar tracking system. It is investigated that temperature profile obtained from PTC solar collector is uniform and collecting heat per unit area is 6.8kcal/$m^2$ min which is about 3 times with compare to flat-plate collector of 2kcal/$m^2$min. Also the amount of heat to be produced from PTC solar collector is 3 Mcal/$m^2$ which is about 2 times with compare to flat-plate collector of 1.5Mcal/$m^2$ as a result of operating these two collectors during one month. Therefore, it is obtained that heat collecting performance of PTC solar collector is superior to flat-plate.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.4
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• pp.417-427
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• 1998

The effect of secondary flow on the heat transfer of a turbulent wake generated by a flat plate was experimentally investigated. The secondary flow was induced in a curved duct in which the flat plate wake generator was installed. All three components of turbulent heat flux were measured in the plane containing the mean radius of curvature of the curved duct. The results showed that mean temperature profiles deviate from the similarity of the straight wake because of the cold fluid transported from the free-stream. The half-width of the mean temperature profile increased rapidly by upwash motion of the secondary flow. The changes to turbulence structure caused by the secondary flow show more pronounced effect on heat transport than on momentum transport. This is because the response to the variation of flow conditions is delayed in temperature field. Negative production of the turbulent heat flux is observed in the inner wake region. From the conditional averaging, it has been found that the negative production of the turbulent heat flux is generated due to a mixing process between the hot and low momentum eddies occupied in the inner wake region and the cold and high momentum eddies in the potential region.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.3
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• pp.228-233
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• 2007

Core technologies for integrating hydrogen gas sensor were investigated. In this study, the thermally isolated micro-hot-plate with areas of $100{\times}100-260{\times}260{\mu}m^2$ was fabricated by utilizing surface micromachining technique that provides better manufacturing yield than bulk micromachining counterpart. The optimum design of the sensor was peformed by analyzing the thermal profile of the structure obtained from a ANSYS simulator. The 400-nm-thick polysilicon films doped with phosphorus, the 300-nm-thick aluminum films, and the 200-nm-thick $SnO_2$(or ZnO)films were used as the micro-heater material, the temperature sensor material, and the gas sensitive material, respectively. The experimental results show that the developed gas sensors can detect $H_2$ concentration as low as 1 ppm.