• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.10 no.1
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• pp.90-95
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• 2014

Local wall thinning is a point of concern in almost all steel structures such as pipe lines covered with a thermal insulator made up of materials with low thermal conductivity(fiberglass or mineral wool); hence, Non Destructive Technique(NDT) methods that are capable of detecting the wall thinning and defects without removing the insulation are necessary. In this study we developed a Pulsed Eddy Current(PEC) system to detect the wall thinning of Ferro magnetic steel pipes covered with fiber glass thermal insulator and shielded with Aluminum plate. The developed system is capable of detecting the wall thickness change through an insulation of thickness 10cm and 0.4mm aluminum shielding. In order to confirm the thickness change due to wall thinning, two different sensors, a hall sensor and coil sensor were used as a detecting element. In both cases, the results show a very good change corresponding to the thickness change of the test specimen. During these experiments a carbon steel tube of diameter 210mm and a length of 620mm, which is covered with insulator of 95mm thickness was used. To simulate the wall thinning, the thickness of the tube is changed for a specified length such as 2.5mm, 5mm and 8 mm from the inner surface of the tube. A 0.4mm thick Aluminum plate was covered on the Test specimen to simulate the shielding of the insulated pipelines. For both hall sensor and coil detection methods Fast Fourier transform(FFT) was calculated using window approach and the results for the test specimen without Aluminum shielding were summarized which shows a clear identification of thickness change in the test specimen by comparing the magnitude spectra. The PEC system can detect the wall thinning under the 95 mm thickness insulation and 0.4 mm Al shielding, and the output signal showed linear relation with tube wall thickness.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.1-6
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• 2008

This paper proposes a game controller that provides user motion input and tactile feedback display, in addition to the traditional button-type input. The device utilizes both an accelerometer and an infrared camera in order to estimate 3D position and to recognize user motion. The information from the accelerometer and the camera are integrated for better performance. Various tactile sensations are presented using a voice-coil type vibrator. We apply the proposed controller to a motion-based game and validate its usability.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.396-401
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• 2009

This paper describes the improvements made on hardware and software of the remote controller for realistic contents. The controller can provide vibrotactile feedback which uses both of a voice-coil actuator and a vibration motor. A vision tracking system for the 3D position of the controller is optimized with respect to the marker size and the camera parameters. We also present the improvements of motion recognition due to the effective motion segmentation and the fusion of vision and acceleration data. We apply the developed controller to realistic contents and validate its usability.

• 한국초전도학회:학술대회논문집
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• v.9
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• pp.373-377
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• 1999

HTS magnet operated at 20${\sim}$40 K was fabricated using three pieces of 100 m Bi-2223 high temperature superconductors fabricated by powder-in-tube process. It was composed of 6 double pancakes with 75 ID. and 113 OD. connected by lab splice. Coil I$_c$ of each DP.(double pancake) obtained for a 140 turn, fabricated using react and wind procedure was 6${\sim}$8 A at 77 K, self field. The maximum field was measured 0.06 T at lop = 5 A, 77 K. The joint resistance due to lap splice of HTS tapes affect badly to operate HTS magnet with persistent current mode, total effective magnet resistance included lap splice was 55 ${\mu}$ ${\omega}$ at 77 K.

• Journal of Chest Surgery
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• v.49 no.2
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• pp.130-133
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• 2016

The rupture of an internal mammary artery (IMA) aneurysm in a patient with type 1 neurofibromatosis (NF-1) is a rare but life-threatening complication requiring emergency management. A 50-year-old man with NF-1 was transferred to the emergency department of Kyungpook National University Hospital, where an IMA aneurysmal rupture and hemothorax were diagnosed and drained. The IMA aneurysmal rupture and hemothorax were successfully repaired by staged management combining endovascular treatment and subsequent video-assisted thoracoscopic surgery (VATS). The patient required cardiopulmonary cerebral resuscitation, the staged management of coil embolization, and a subsequent VATS procedure. This staged approach may be an effective therapeutic strategy in cases of IMA aneurysmal rupture.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.218-223
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• 2008

Cell-phone becomes a necessary communication device in modern society. However, a paging signal by a sound transducer often acts as an unpleasant noise, thus necessitating a paging signal by a vibration motor. The conventional flat type vibration motor uses three-phase windings with three phase coils. In this article, a new design of a vibration motor using a V connection with two phase coils is presented, increasing mass productivity. For electromagnetic field analysis, due to the motor symmetry, two-dimensional modeling can be implemented for fast computation, and performance is predicted by the finite element method. The winding distribution angle turns out to be the most important design parameter for the elimination of dead points, and a new coil configuration is suggested which has no adverse effect on motor size and weight. Experimental tests of vibration confirm the validity of the proposed design.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.52 no.1
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• pp.17-23
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• 2016

This study investigates the development of an automatic lightening buoy that can indicate an aquaculture cage at night or in rough weather. The energy for the light is generated by the linear motion of a magnet along with a coil inside the buoy as the waves cause the buoy to oscillate up and down. The principle of the magnet motion is different between the magnet and body of the buoy because the movement of the latter is dependent on the surface wave, while the former is affected by the damper. To obtain a quantitative performance of the buoy, the voltage as well as up and down motion produced by several waves were measured in the wave tank. A shorter wave period, i.e., faster motion, of the magnet produced a brighter light. It is expected that this study can aid in deciding the optimum design of a buoy capable of producing a bright light at any aquaculture site affected by sea or fresh water waves.

• Bulletin of the Korean Chemical Society
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• v.30 no.3
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• pp.667-670
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• 2009

The understanding of behaviors of hydroperoxyl/superoxide anion radicals (${H_2O_2}^./{O_2}^{-.}$) generated from a photoirradiated $TiO_2$ surface is essential to improve the efficiency of $TiO_2$ photocatalytic reactions by decreasing the recombination of photoinduced electron-hole ($e^--h^+$) pairs. In contrast with previous studies, we found that ${H_2O_2}^./{O_2}^{-.}$ generated on the surface of illuminated $TiO_2$ particles are mobile. ${H_2O_2}^./{O_2}^{-.}$ formed by the photocatalysis of $TiO_2$ particles immobilized onto the inner surface of a coil-quartz tube were forced under a continuous flow through a knotted tubing reactor (KTR) and into the aqueous phase completely separated from the $TiO_2$ particles, and were measured by a chemiluminescence (CL) technique using 2-methyl-6-(p-methoxyphenyl)-3,7-dihydroimidazo[ 1,2-a]pyrazin-3-one (MCLA) as the reagent. The initial concentration of the ${H_2O_2}^./{O_2}^{-.}$ stream entering the KTR was determined by its half-life (98 s) at pH 5.8. We suggests that the efficiency of $TiO_2$ photocatalytic reactions may be further improved by utilizing the mobility of ${H_2O_2}^./{O_2}^{-.}$.

• Nuclear Engineering and Technology
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• v.45 no.3
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• pp.347-360
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• 2013

This paper presents an experimental investigation of the small-break loss-of-coolant accident (SBLOCA) and the loss-of-feedwater accident (LOFW) in a scaled integral test facility of REX-10. REX-10 is a small integral-type PWR in which the coolant flow is driven by natural circulation, and the RCS is pressurized by the steam-gas pressurizer. The postulated accidents of REX-10 include the system depressurization initiated by the break of a nitrogen injection line connected to the steam-gas pressurizer and the complete loss of normal feedwater flow by the malfunction of control systems. The integral effect tests on SBLOCA and LOFW are conducted at the REX-10 Test Facility (RTF), a full-height full-pressure facility with reduced power by 1/50. The SBLOCA experiment is initiated by opening a flow passage out of the pressurizer vessel, and the LOFW experiment begins with the termination of the feedwater supply into the helical-coil steam generator. The experimental results reveal that the RTF can assure sufficient cooldown capability with the simulated PRHRS flow during these DBAs. In particular, the RTF exhibits faster pressurization during the LOFW test when employing the steam-gas pressurizer than the steam pressurizer. This experimental study can provide unique data to validate the thermal-hydraulic analysis code for REX-10.

• Nuclear Engineering and Technology
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• v.45 no.4
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• pp.439-458
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• 2013

REX-10 is a fully-passive small modular reactor in which the coolant flow is driven by natural circulation, the RCS is pressurized by a steam-gas pressurizer, and the decay heat is removed by the PRHRS. To confirm design decisions and analyze the transient responses of an integral PWR such as REX-10, a thermal-hydraulic system code named TAPINS (Thermal-hydraulic Analysis Program for INtegral reactor System) is developed in this study. Based on a one-dimensional four-equation drift-flux model, TAPINS incorporates mathematical models for the core, the helical-coil steam generator, and the steam-gas pressurizer. The system of difference equations derived from the semi-implicit finite-difference scheme is numerically solved by the Newton Block Gauss Seidel (NBGS) method. TAPINS is characterized by applicability to transients with non-equilibrium effects, better prediction of the transient behavior of a pressurizer containing non-condensable gas, and code assessment by using the experimental data from the autonomous integral effect tests in the RTF (REX-10 Test Facility). Details on the hydrodynamic models as well as a part of validation results that reveal the features of TAPINS are presented in this paper.