• Archives of Reconstructive Microsurgery
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• v.22 no.1
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• pp.38-41
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• 2013

A 31-year-old female patient presented with a skin and soft tissue defect measuring $8{\times}6cm$ in size with exposure of the extensor hallucis longus tendon and the first metatarsal bone after metatarsal lengthening for brachymetatarsia. The defect was covered with a distally based dorsalis pedis flap based on the distal communicating branch of the dorsalis pedis artery. Secondary defect was covered by a split thickness skin graft. There was congestion of the flap tip after the operation; however, it was resolved using medical leeches and anti-coagulants. No necrosis or infection was encountered and the contour of the flap was satisfactory. There was no donor site morbidity. Reverse dorsalis pedis flap has not been commonly used due to the anatomical variation and uncertainty, which is different from the reverse radial forearm flap. However, when faced with the challenge of a moderate soft tissue defect of the distal forefoot, we believe that the reverse dorsalis pedis flap offers a good option with various advantages.

• Transactions of the Society of Information Storage Systems
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• v.5 no.2
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• pp.82-88
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• 2009

Understanding the adhesion behavior and characteristics of toner film is required to achieve image and text printing with high quality resolution. Toner can be considered as a thin film coating on a media such as paper or polymer film. Quantitative measurement of adhesion characteristics of the thin film is important to assess the reliability of the system. In this work the main objective was to investigate the adhesion characteristic between the toner and the media by ramp loading scratch test method. The scratch test may be used to obtain quantitative information about the adhesion of the film to the substrate. In the scratch test a diamond tip was used to scratch the surface of the toner film under an increasing normal load until the toner detached or fractured. The critical load (LC) was obtained from the experimental results. Also, the relationship between the critical load and the adhesive strength of the interface between the substrate and the toner was obtained by measuring the normal and tangential forces during the scratch test. Finally, theoretical analysis of the toner scratch characteristics was performed based on Benjamin and Weaver theory, Plowing model, and Laugier model.

• 한국연소학회:학술대회논문집
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• 1998.10a
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• pp.9-21
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• 1998

The optimization of frontal device including fuel nozzle and swirler is required to secure the mixing of fuel and air, and the combustion stability in the gas turbine combustor design for the reduction of pollutant emissions and the increase of combustion efficiency. The effects of injection nozzle and swirler on the flow field, spray characteristics and consequently the combustion stability, were experimentally investigated by measuring the velocity field, droplet sizes of fuel spray, lean combustion limit and the temperature field in the main combustion region. The effect of fuel injection nozzle was tested by adopting three different nozzles; a dual orifice fuel nozzle, a hollow cone nozzle and a solid cone nozzle. These tests were combined with the three different swirler geometries; a dual-stage swirler with 40$^{\circ}$ /-4 5$^{\circ}$ vanes and two single-stage swirlers with 40$^{\circ}$ vane angle having 12 and 16vanes, respectively. Flow fields and spray characteristics were measured with APV(Adaptive Phase Doppler Velocimetry) under atmospheric condition using kerosine fuel. Temperatures were measured by Pt-PtI3%Rh, R-type thermocouple which was 0.2mm thick. It was found that the dual swirler resulted in the biggest recirculation zone with the highest reverse flow velocity at the central region, which lead the most stable combustion. The various combustion characteristics were observed as a function of the combination between the injector and swirler, that gave a tip for the better design of gas turbine combustor.

• Journal of Ocean Engineering and Technology
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• v.2 no.2
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• pp.104-111
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• 1988

This paper deals with the micro-surface-cracks behavior on the unnotched smooth specimens of Type 304 stainless steel at $593^{\circ}C$ in air under creep and creep-fatigue conditions that have 10 mim and 1 min load holding times respectively. The behaviors of the micro-surface-cracks have been visualized by means of surface replica method and optical micro-photography. The quantitative characteristics of initiation, growth and coalescence of micro-surface-cracks have been investigated by observing and measuring the crack growth behaviors. some of the important results are as follows: Main crack initiates at grain boundary in the early stage(10 to 20%)of its life time and grows through coalescence and finally leads to fracture. The distribution of micro-surface-crack length, 2a, can be plotted against the composite Weibull distribution. The growth rate of the main crack can be plotted against the stress intensity factor, crack tip opering displacement and J integral.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.60-65
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• 2004

Kim et al. described and compared other methods of measuring stress triaxiality using the displacements near the side necking, proved the validities of these models and explored the effect of location where the displacements are measured using three-dimensional finite element analysis for a standard CT specimen with 20% side-grooves. In this paper, the applicability of these models to various specimen and materials are examined in detail. To consider the effects of side groove, thickness of specimen, crack length, specimen geometry and strain hardening exponents, three-dimensional finite element simulation has been performed for various specimen geometries. For a case without a side groove, in the whole the difference between the stress triaxilaity analytically evaluated and directly determined is similar. For a case with a 20% side groove the stress triaxiality is measured at the area where ${\theta}$ is smaller than $60^{\circ}$, which excludes a side grooved area.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.4
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• pp.432-440
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• 2007

In this study, we have investigated the closure behavior of fatigue cracks in SAPH440 steel plates under a mixed-mode I+II loading. A crack image capturing system as a direct measuring method was used to measure the closure levels at a crack tip. The crack closure levels in the fluctuation and stable sections were increased with the increase of the mode mixture ratio. The mode mixture ratio independent fatigue crack propagation rates equation was calculated by considering mixed-mode crack closure levels. The equation was examined according to the application method of crack opening ratio. The fracture surface analysis by C-scan method was also performed in order to investigate the closure mechanism and propagation mode of crack under the mixed-mode I+II loading. The crack closure under the mixed mode I+II is confirmed as a surface roughness closure by the quantitative analysis of fracture surface using the proposed surface roughness parameter.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.31 no.2
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• pp.143-148
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• 2009

Introduction: To correct abnormal occlusal plane by orthognathic surgery, we need to have clear criteria for therapeutic occlusal plane. Authors introduced the concept of individualized ideal occlusal plane(Y-plane), which is determined by the size and form of the mandible, and the ideal incisor tip considering upper and lower lip. Authors studied the following to verify if the actual occlusal plane of the patients with optimal jaw relationship corresponds with the individualized ideal occlusal plane. Patients: We reviewed 44 patients who have normal occlusion visitied in the Dept. of orthodontics, Pundang CHA hospital. Methods: We evaluated if there are agreement between individualized ideal occlusal plane(Y plane) and occlusal plane of actual patients. And we confirmed if tested group has a normal face by measuring FABA, FMA, AB-LOP. Results: There were no significant differences of FABA, FMA, AB-LOP, Mo-Y plane between male and female. FABA, FMA and AB-LOP were included in the normal value. Average distance of Mo-Y plane was $0.75{\pm}0.78mm$. Conclusion: Individualized ideal occlusal plane may be applied to orthognathic surgery.

• Journal of ILASS-Korea
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• v.10 no.4
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• pp.1-7
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• 2005

The purpose of this study is to investigate the effect of swirler vane angle and the aspect ratio of swirl chamber of nozzle on the characteristics of single spray. The characteristics of sprat's have been investigated by measuring the spray angle, droplet size and velocity Visualization of spray was conducted to obtain the spray angle and breakup process. The spray characteristics such as droplet size and velocity were measured by Phase Doppler Anemometry(PDA). It was found that the spray angle was increased with increasing the swirler angle. For both sprays, the axial velocity and SMD were decreased with increasing the swirler vane angle. It was also shown that the axial velocity and SMD were decreased with increasing the aspect ratio of swirl chamber The effect of vane angle un the spray characteristics was greater than the aspect ratio of swirl chamber for single spray.

• Journal of ILASS-Korea
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• v.9 no.4
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• pp.31-37
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• 2004

This paper presents spray and combustion characteristics of hydrocarbon fuel injected from pressure-swirl nozzles. Three commercial nozzles with orifice diameters of 0.256, 0.308 and 0.333mm and injection pressures ranging from 0.7 to 1.3 MPa were selected f9r the experiments. Spray characteristics such as breakup length. spray angle and drop size (SMD) were analyzed using photo image analyses and Malvern Panicle Size Analyzer. The drop size was measured with and without a blower at the same measuring locations. The flame length and width were measured using photo image analyses. The temperature distribution along the axial distance and the gas emission such as CO, $CO_2\;and\;NO_x$ were studied. The breakup length decreased with an increase in injection pressure for each nozzle but increased with an increase in nozzle orifice diameter. The spray angle increased and SMD decreased with an increase in injection pressure. The flame with an increased linearly with an increase in injection pressure and in nozzle orifice diameter. The flame temperature increased with an increase in injection pressure but decreased along the axial distance. The maximum temperatures occurred closer to the burner exit and flame at axial distance of 242mm from the diffuser tip. The experimental results showed that the level of CO decreased while that of $CO_2\;and\;NO_x$ increased with an increase in injection pressure and nozzle orifice diameter.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.8
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• pp.30-38
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• 2011

This paper proposes a new intelligent diagnosis equipment for the partial discharge, which keeps deteriorating the insulating materials inside electric machineries, ultimately leading to electrical breakdown. In order to simulate experimentally the partial discharge inside the electric machinery, the tip-to-plate, the sphere-to-plate, the sphere-to-sphere and the plate-to-plate electrodes are used respectively, of which the gaps are 1[mm], 3[mm] or 5[mm] and the applied voltages are 3[kV], 5[kV] or 7[kV]. Ceramic coupler sensor and FIR digital filter are used to measure the partial discharge and the artificial neural network is used for the deterioration diagnosis of the electric machinery. The microprocessor of PD diagnosis equipment is DSP (TMS320C6713) with FPGA (Cyclone II). The results of the real-time and on-line experiments performed with the developed equipment are also explained.