• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.6
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• pp.691-698
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• 2012

The joining of aluminum and HSS (high-strength steel) by the conventional clinching process is limited by the low formability of HSS. Defects in the clinching joint, such as necking of the upper sheet, cracks, and lack of interlocking, are produced by the different ductility properties of HSS and aluminum. In this study, we propose the hole clinching process for joining Al6061 and SPFC440, in which deformation of SPFC440 is avoided by drilling a hole in the SPFC440. The dimensions of the interlocking in the hole-clinched joint necessary to provide the required joint strength were determined. Based on the volume constant of the hole clinching process, the shapes of the tools were designed by finite element (FE)-analysis. A hole clinching experiment was performed to verify the proposed process. A cross-section of the joint showed good agreement with the results of the FE-analysis. The lap shear strength was found to be 2.56 kN, which is higher than required joint strength.

• Electrical & Electronic Materials
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• v.10 no.1
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• pp.8-14
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• 1997

The UV/O$_{3}$ dry cleaning has been well known in removing organic molecules. The UV/O$_{3}$ dry cleaning method was performed to clean the Si wafer surfaces and contact holes contaminated by organic molecules such as residual PR. During the cleaning process, the Si surfaces were analyzed with X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) and ellipsometer. When the UV/O$_{3}$ dry cleaning at 200'C was performed for 3 minutes, the residual photoresist was almost removed on Si wafer surfaces, but Si surfaces were oxidized. For UV/O$_{3}$ application of contact hole cleaning, the contact string were formed using the equipment of ISRC (Inter-university Semiconductor Research Center). Before Al deposition, UV/O$_{3}$ (at 200.deg. C) dry cleaning was performed for 3 minutes. After metal annealing, the specific contact resistivity was measured. Because UV/O$_{3}$ dry cleaning removed organic contaminants in contact holes, the specific contact resistivity decreased. Each contact hole size was different, but the specific contact resistivities were all much the same. Thus, it is expected that the UV/O$_{3}$ dry cleaning method will be useful method of removal of the organic contaminants at smaller contact hole cleaning.

• Natural Product Sciences
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• v.15 no.3
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• pp.115-120
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• 2009

Woohwangcheongsimwon (WHCSW) is a traditional oriental medicinal fomula which has been clinically used for treating strokes, palpitation, loss of consciousness and anxiety. The purpose of this study was to characterize the putative anxiolytic properties of WHCSW using an elevated plus-maze (EPM) and hole-board test. Control mice were orally treated with an equal volume of vehicle (10% Tween 80 solution), and positive control mice were treated with diazepam (1 mg/kg, i.p.). In the EPM test, WHCSW significantly increased the percentage of time-spent in the open arms (200 mg/kg, P < 0.05) and the percentage of open arm entries (200 and 400 mg/kg, P < 0.05). WHCSW also significantly increased the number of head-dips in the hole-board test (200 mg/kg, P < 0.05). In addition, the anxiolytic properties of WHCSW examined in the EPM test were inhibited by flumazenil (10 mg/kg, i.p.), a GABA$_A$ antagonist. However, no changes in spontaneous locomotor activity or myorelaxant effects were observed versus 10% Tween 80 controls. These results suggested that WHCSW is an effective anxiolytic agent, and that its anxiolytic effects are mediated via GABA$_A$ receptors.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.12
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• pp.959-966
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• 2013

In this study, based on P-3CK project using aging aircraft without any design information, the structural assessments of fastener holes to repair the short edge distance defects are investigated. For this purpose, the nacelle longeron which has many defects is selected and then conservative stress is calculated by performing the static analysis of 1.5ED, 1.8ED, 2.0ED defects of longeron fastener holes. This result applies to TWIST standard load spectrum to generate flight load spectrum. Then the crack growth analysis is performed by using flight load spectrum. Through this, the validity of a repaired fastener hole is evaluated. Finally, the standard of repair and the period of maintenance for a defected fastener hole are established.

• Journal of Information Display
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• v.7 no.4
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• pp.9-12
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• 2006

This paper reports the synthesis and electroluminescent properties of new aromatic compounds as hole-transporting materials based on phenothiazine, such as 1,4-diphenothiazyl-benzene [DPtzB], 1,4-diphenothiazyl-xylene [DPtzX] and 9,10-diphenothiazyl-anthracene [DPtzA]. DPtzB thin film exhibited photoluminescence (PL) maximum emission peak and emission shoulder at 450 and 475 nm, and a maximum emission at 447 nm without emission shoulder was obtained in DPtzX thin film. When DPtzA was excited by incident light of 359 nm, DPtzA showed strong PL emission at 417 nm and weak emission at 600 nm. Luminance efficiency of DPtzB, DPtzX and DPtzA-based electroluminescence (EL) devices was 3.57, 3.46 and 0.47 cd/A, and power efficiency of DPtzB, DPtzX and DPtzA-based EL devices was 1.48, 1.26 and 0.201 m/W.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.2
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• pp.195-201
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• 2012

According to many customers' requests, optical measurement module (OMM) applications using automatic measuring devices to measure the machined part rapidly on a machine tool have increased steeply. Touch trigger probes are being used for job setup and feature inspection as automatic measuring devices, and this makes quality checking and machining compensation possible. Therefore, in this study, the use of touch trigger probes for accurate measurement of the machined part has been studied and a macro program for a hole measuring cycle has been developed. This hole is the most common feature to be measured, but conventional methods are still not free from measuring error. In addition, the eccentricity change of the least square circle was simulated according to the roundness error in a hole measurement. To evaluate the reliability of this study, the developed hole-measuring program was executed to measure the hole plate on the machine and verify the roundness error in the eccentricity simulation result.

• Archives of Craniofacial Surgery
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• v.12 no.1
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• pp.12-16
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• 2011

Purpose: This study examined the biomechanical stability of four different plating techniques in the experimental model of mandibular subcondyle fracture. Methods: Twenty standardized bovine tibia bone samples ($7{\times}1.5{\times}1.0cm$) were used for this study. Each of the four sets of tibia bone was cut to mimic a perpendicular subcondyle fracture in the center area. The osteotomized tibia bone was fixed using one of four different fixation groups (A,B,C,D). The fixation systems included single 2.0 mm 4 hole mini adaption plate (A), single 2.0 mm 4 hole dynamic compression miniplate (B), double fixation with 2.0 mm 4 hole mini adaption plate (C), double fixation with a 2.0 mm 4 hole mini adaption plate and 2.0 mm 4 hole dynamic compression miniplate (D). A bending force was applied to the experimental model using a pressure machine (858 table top system, $MTS^{(R)}$) until failure occurred. The load for permanent deformation, maximum load of failure were measured in the load displacement curve with the chart recorder. Results: Double fixation with a 2.0 mm 4 hole mini adaption plate and a 2.0 mm 4 hole dynamic compression miniplate (D) applied to the anterior and posterior regions of the subcondyle experimental model showed the highest load to failure. Conclusion: From this study, double fixation with an adaption plate and dynamic compression miniplate fixation technique produced the greatest biomechanical stability. This technique may be considered a useful means of fixation to reduce the postoperative internal maxillary fixation period and achieve early mobility of the jaw.

• Journal of the Korean Physical Society
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• v.73 no.10
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• pp.1420-1430
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• 2018

We investigate an entangled system, which is analogous to a composite system of a black hole and Hawking radiation. If Hawking radiation is well approximated by an outgoing particle generated from pair creation around the black hole, such a pair creation increases the total number of states. There should be a unitary mechanism to reduce the number of states inside the horizon for black hole evaporation. Because the infalling antiparticle has negative energy, as long as the infalling antiparticle finds its partner such that the two particles form a separable state, one can trace out such a zero energy system by maintaining unitarity. In this paper, based on some toy model calculations, we show that such a unitary tracing-out process is only possible before the Page time while it is impossible after the Page time. Hence, after the Page time, if we assume that the process is unitary and the Hawking pair forms a separable state, the internal number of states will monotonically increase, which is supported by the Almheiri-Marolf-Polchinski-Sully (AMPS) argument. In addition, the Hawking particles cannot generate randomness of the entire system; hence, the entanglement entropy cannot reach its maximum. Based on these results, we modify the correct form of the Page curve for the remnant picture. The most important conclusion is this: if we assume unitarity, semi-classical quantum field theory, and general relativity, then the black hole should violate the Bekenstein-Hawking entropy bound around the Page time at the latest; hence, the infinite production arguments for remnants might be applied for semi-classical black holes, which seems very problematic.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.86.2-86.2
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• 2014

We present a new ray-tracing code, "Odyssey", for the Kerr spacetime accelerated by the Graphics Processing Unit (GPU). Taking advantage of the ability of nVidia graphic cards to evaluate trajectories of a large amount of photon simultaneously, the code is two orders of magnitude as fast as the previous CPU-based code corresponding to the speed of few nanoseconds per photon per time step. In the light of the Graphic User Interface (GUI) powered by the GPU-enhanced 2D/3D displaying technique, DirectX, it is feasible for users to manipulate diverse results such as rotating and zooming in/out the trajectories of photon instantly near the black hole. Thus the Odyssey can serve as a tool not only for scientific but also for the educational purpose. We discuss possible applications in detail in light of several results such as the shape of the silhouette of a black hole, the shape of a hot spot orbiting a black hole, and 3D photon trajectories.

• Journal of Astronomy and Space Sciences
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• v.33 no.3
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• pp.197-205
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• 2016

We investigated two flares in the solar atmosphere that occurred on June 3, 2012 and July 6, 2012 and caused propagation of Moreton and EIT waves. In the June 3 event, we noticed a filament winking which presumably was caused by the wave propagation from the flare. An interesting feature of this event is that there was a reflection of this wave by a coronal hole located alongside the wave propagation, but not all of this wave was transmitted by the coronal hole. Using the running difference method, we calculated the speed of Moreton and EIT waves and we found values of 926 km/s before the reflection and 276 km/s after the reflection (Moreton wave) and 1,127 km/s before the reflection and 46 km/s after the reflection (EIT wave). In the July 6 event, this phenomenon was accompanied by type II and type III solar radio bursts, and we also performed a running difference analysis to find the speed of the Moreton wave, obtaining a value of 988 km/s. The speed derived from the analysis of the solar radio burst was 1,200 km/s, and we assume that this difference was caused by the different nature of the motions in these phenomena, where the solar radio burst was caused by the propagating particles, not waves.