• Proceedings of the SAREK Conference
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• 2006.06a
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• pp.182-187
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• 2006

This research presented the heat resistance characteristics of heat sink which is newly designed through the experiment. For the same volume and base plate of heat sinks, the experiment of heat transfer characteristics was conducted for forced convection of layered type heat sink. The heat transfer and pressure drop characteristics of the layered type heat sink were compared for the various kinds of fin pitches, fin heights and heights of heat sink. The results show that thermal resistance is decreased as the height of heat sink increases and the fin height and fin pitch decrease, From the experimental data of layered type heat sink, the correlation equation of Nusselt number was obtained as follows ; $$Nu=0.845{\cdot}Re^{0.393}{\cdot}(\frac{f_h}{D_h})^{0.160}{\cdot}(\frac{f_p}{D_h})^{0.372}{\cdot}(\frac{H_{hs}}{D_h})^{-0.942}$$

• Safety and Health at Work
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• v.7 no.2
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• pp.130-137
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• 2016

At a brewery, the base plate-to-shell weld seam of a $90-m^3$ vertical cylindrical steel tank failed catastrophically. The 4 ton tank "took off" like a rocket leaving its contents behind, and landed on a van, crushing it. The top of the tank reached a height of 30 m. The internal overpressure responsible for the failure was an estimated 60 kPa. A rupture disc rated at < 50 kPa provided overpressure protection and thus prevented the tank from being covered by the European Pressure Equipment Directive. This safeguard failed and it was later discovered that the rupture disc had been installed upside down. The organizational root cause of this incident may be a fundamental lack of appreciation of the hazards of large volumes of low-pressure compressed air or gas. A contributing factor may be that the standard piping and instrumentation diagram (P&ID) symbol for a rupture disc may confuse and lead to incorrect installation. Compressed air systems are ubiquitous. The medium is not toxic or flammable. Such systems however, when operated at "slight overpressure" can store a great deal of energy and thus constitute a hazard that ought to be addressed by safety managers.

• Korean Journal of Applied Biomechanics
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• v.31 no.2
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• pp.126-132
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• 2021

Objective: The purpose of this study was to investigate how three gaze directions (bottom, normal, up) affects the coordination and stability of the lower limb during drop landing. Method: 20 female adults (age: 21.1±1.1 yrs, height: 165.7±6.2 cm, weight: 59.4±5.9 kg) participated in this study. Participants performed single-leg drop landing task on a 30 cm height and 20 cm horizontal distance away from the force plate. Kinetic and kinematic data were obtained using 8 motion capture cameras and 1 force plates and leg stiffness, loading rate, DPSI were calculated. All statistical analyses were computed by using SPSS 25.0 program. One-way repeated ANOVA was used to compared the differences between the variables in the direction of gaze. To locate the differences, Bonferroni post hoc was applied if significance was observed. Results: The hip flexion angle and ankle plantar flexion angle were significantly smaller when the gaze direction was up. In the kinetic variables, when the gaze direction was up, the loading rate and DPSI were significantly higher than those of other gaze directions. Conclusion: Our results indicated that decreased hip and ankle flexion angles, increased loading rate and DPSI when the gaze direction was up. This suggests that the difference in visual information can increase the risk of injury to the lower limb during landing.

• Nuclear Engineering and Technology
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• v.54 no.1
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• pp.357-373
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• 2022

The high-temperature gas-cooled reactor pebble-bed module project is the first commercial Generation-IV NPP(Nuclear Power Plant) in China. A new joint is used for the vertical support of RPV(Reactor Pressure Vessel). The steel corbel is integrally embedded into the reactor-cabin wall through eight asymmetrically arranged pre-stressed high-strength bolts, achieving the different path transmission of shear force and moment. The vertical monotonic loading test of two specimens is conducted. The results show that the failure mode of the joint is bolt fracture. There is no prominent yield stage in the whole loading process. The stress of bolts is linearly distributed along the height of corbel at initial loading. As the load increases, the height of neutral axis of bolts gradually decreases. The upper and lower edges of the wall opening contact the corbel plate to restrict the rotation of the corbel. During the loading, the pre-stress of some bolts decreases. The increase of the pre-stress strength ratio of bolts has no noticeable effect on the structure stiffness, but it reduces the ultimate bearing capacity of the joint. A simplified calculation model for the elastic stage of the joint is established, and the estimation results are in good agreement with the experimental results.

• Korean Journal of Materials Research
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• v.19 no.1
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• pp.28-32
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• 2009

Silicon carbide (SiC) is a promising material for power device applications due to its wide band gap (3.26 eV for 4H-SiC), high critical electric field and excellent thermal conductivity. The Schottky barrier diode is the representative high-power device that is currently available commercially. A field plate edge-terminated 4H-SiC was fabricated using a lift-off process for opening the Schottky contacts. In this case, Ni/Ti dual-metal contacts were unintentionally formed at the edge of the Schottky contacts and resulted in the degradation of the electrical properties of the diodes. The breakdown voltage and Schottky barrier height (SBH, ${\Phi}_B$) was 107 V and 0.67 eV, respectively. To form homogeneous single-metal Ni/4H-SiC Schottky contacts, a deposition and etching method was employed, and the electrical properties of the diodes were improved. The modified SBDs showed enhanced electrical properties, as witnessed by a breakdown voltage of 635 V, a Schottky barrier height of ${\Phi}_B$=1.48 eV, an ideality factor of n=1.04 (close to one), a forward voltage drop of $V_F$=1.6 V, a specific on resistance of $R_{on}=2.1m{\Omega}-cm^2$ and a power loss of $P_L=79.6Wcm^{-2}$.

• Journal of Korean Foot and Ankle Society
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• v.16 no.2
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• pp.94-100
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• 2012

Purpose: The purpose of this study is to analyze the clinical features of distal tibia fractures and to evaluate the treatment outcomes of minimally invasive plate osteosynthesis (MIPO). Materials and Methods: From January 2004 to December 2009, 84 cases of 81 patients treated with plate fixation for distal tibia fracture were enrolled in this retrospective review. We investigated age, sex, injury mechanism, fracture patterns, and complications, and the clinical features were analyzed. To evaluate the treatment outcomes of MIPO, we divided into two groups. MIPO group consisted of 55 patients were treated with MIPO technique and conventional group consisted of 18 patients were treated with open reduction and internal fixation with conventional anterolateral plating. The results were compared between two groups by assessing bony union time, operation time, amount of blood loss, range of ankle motion, clinical score by American Orthopaedic Foot and Ankle Society (AOFAS) score, and post-operative complications. Results: The mean age of 81 patients with distal tibia fracture was 54.8 years. According to AO classification, A1:2:3 were 16, 20, 16 patients, B1:2:3 were 2, 8, 7, C1:2:3 were 1, 3, 11 patients. According to injury mechanism, slip down injury was patients, traffic accident was 26, fall from height injury was 14 patients respectively. The type A fractures were lower energy trauma and more older patients. The type C fractures were higher energy trauma and younger patients. MIPO group was better than conventional group in operative time, blood loss, bony union time, and ankle joint motion. In complications, MIPO group showed no nonunion and infection, one malunion, one skin necrosis, nine skin irritations, and one screw breakage. Conventional group showed two nonunion, four infections, two skin necrosis, and one metal failure. Conclusion: Distal tibial fractures caused by low energy trauma were on the increase. Minimal invasive plate osteosynthesis was shorter bony union time and operation time, less blood loss, and larger ankle motions than conventional open reduction and plate fixation.

• Journal of the Korea Convergence Society
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• v.9 no.9
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• pp.31-39
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• 2018

In this paper, we proposed a license plate detection method based on contour extraction that adapts to environmental changes. The proposed method extracts contour lines using DoG (Difference of Gaussian) to remove unnecessary noise parts in the contour extraction process. Binarization was applied in ugly outline images, and erosion and dilation operations were used to emphasize the contour of the character part. Then, only the outline of the ratio of the characters of the plate was extracted through the ratio of the width and height of the characters. And the case where the outline is the longest is estimated by estimating the characters of the license plate. For the experiment, we applied 130 image data to license plate on the front of the vehicle, oblique environment, and environment images with various backgrounds. I also experimented with motorcycle images of different license plate patterns. Experimental results showed that the detection rate of the oblique image was 93% and that of the various background environment was 70% in the motorcycle image but 98% in the front image.

• Clinics in Shoulder and Elbow
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• v.12 no.1
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• pp.44-52
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• 2009

Purpose: We assessed the radiographic and clinical results of one surgeon's experience treating proximal humerus fractures with a locked proximal humeral plate. Materials and Methods: Twenty patients with unstable proximal humerus fractures were treated with a locking compression plate between February 2005 and September 2007. The average age of the patients was 60.6 years, and the average postoperative follow-up period was 22.3 months. The clinical results were evaluated using the Constant and DASH scores. The radiologic results were evaluated by the Paavolainen method, which measures the neck shaft angle and humeral head height. Results: At the last follow-up examination, the mean Constant score was 75.3 and 15 cases (75%) had excellent or good results; the mean DASH score was 16.4. The mean neck shaft angle was $137.1^{\circ}$, and 19 cases (95%) had good results by the Paavolainen method. There was one delayed union, malunion, and screw loosening. Conclusion: The patients treated with a locking compression plate had relatively good clinical and radiologic results, and a low complication rate. Moreover, the patients could exercise earlier due to good reduction and initial stability. Treatment of unstable proximal humerus fractures with a locking compression plate is a reliable method.

• Journal of the Korea Institute of Building Construction
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• v.13 no.5
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• pp.482-490
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• 2013

Although the flat plate system is an efficient structural type due to the simplicity of its construction, the low story height, and the various plan design, the slab-column connections are vulnerable to punching shear failure from gravity load and eccentric shear failure from lateral load. To prevent the structure collapse, various construction methods of slab-column connection reinforcement are developed but none of these satisfies all of structural performance, economics, and constructability. This paper presents the reinforcement of slab-column connection with lattice bars. The structural performance is confirmed with the interior slab-column connection tests subjected to cyclic loading, and the economic feasibility is demonstrated from the structural design under the same condition with lattice bars, stud rails, and stirrups.

• Journal of the Korea Fashion and Costume Design Association
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• v.6 no.2
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• pp.49-62
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• 2004

By delivery means of fashion information, fashion dolls appeared in 18th century. According to development of printing, delivery means of fashion information changed from fashion dolls to fashion plates. Fashion plates offer a colorful and in depth view of the stylish fashions of the past. First fashion plate was Hollars print that was inserted to $\ulcorner$La Galerie des Modes et Costumes Francais$\lrcorner$ and that was published at England in 1643. First fashion plate in France could assumes as winter deshabill that was inserted to $\ulcorner$Le Mercure Galant$\lrcorner$ in 1678. The widespred publication of fashion plates began in England and France in the late 18th century. The first true fashion magazine $\ulcorner$The Ladys Magazine$\lrcorner$ was published at London in 1770. And suddenly similar plates were being published all over Europe. Fashion plates reached their height of popularity in the mid-1800s. Modern age in Europe for fashion magazines golden age, hundreds kinds of fashion magazines published in Europe. Copyright laws in Europe were not enforced, resulting in widespread piracy of fashion designs and plates. After 19th century, America and Europe used much Paris imitation plate. $\ulcorner$The Ladys Magazine$\boxUl$, $\ulcorner$La Gallerie des Modes et Costumes Francais$\lrcorner$, $\ulcorner$Les Cabinet des Modes$\lrcorner$, $\ulcorner$Journal des Dames et des Modes$\lrcorner$, $\ulcorner$The Ladys Monthly Museum$\lrcorner$ were the important fashion magazines in 18th century. $\ulcorner$The Ladys Pocket Magazine$\lrcorner$, $\ulcorner$La Mode$\lrcorner$, $\ulcorner$Le Follet$\lrcorner$, $\ulcorner$La Mode Illustree$\lrcorner$, $\ulcorner$$\ulcorner$The Queen$\lrcorner$ were the important fashion magazines in 19th century. $\ulcorner$Journal des Dames et des Modes$\lrcorner$, $\ulcorner$Gazette du bon ton$\lrcorner$ were the important fashion magazines in early 20th century.