• Journal of the Korean Society of Radiology
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• v.17 no.4
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• pp.497-506
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• 2023

In the case of radiation workers in medical institutions, radiation exposure is made for patient protection and accurate procedures, so they have a problem of low dose exposure. Low-dose radiation exposure occurs mainly in parts of the body other than the Apron area, and the most frequent place is the skin of the back of the hand. In particular, since the medical personnel's hands require senses and fine movements during the procedure, they are defenseless in the radiation exposure area and are at risk of exposure. It can solve the problem of shielding such as lead gloves, and it is difficult to use by suggesting the activity of the hand during the procedure. To solve this problem, a shielding cream capable of obtaining a functional radiation protection effect was developed and its shielding performance was compared with lead equivalent of 0.1 mmPb. In the process of manufacturing shielding cream, the shielding performance was improved by adding a defoaming process to reduce air holes to increase the density of the cream. Therefore, the shielding cream using barium sulfate as the main material has a lower shielding rate than the lead plate, and in the realm of effective energy, it is 59%, At high effective energy, a difference of about 37% was shown, indicating that there is a functional radiation protection effect. The advantage is that it can be used directly on the skin, and it is considered that it can be used before wearing surgical gloves and has a permanent protective effect.

• Proceedings of the KWS Conference
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• 2008.05a
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• pp.35-35
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• 2008

• Transactions of Materials Processing
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• v.30 no.1
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• pp.35-42
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• 2021

Magnesium alloys are used in electronic devices such as laptops due to their lightweight features as well as vibration absorption and electromagnetic shielding properties. However, the precision of electronics is limited by the large number of small and precise ribs, the cost-effective manufacture of which requires appropriate technology. Plate forging is an efficient manufacturing process that can address these challenges. In this study, plate forging of magnesium alloys was investigated specifically for the fabrication of laptop cover. The plate forging process with back-pressure was used for near-net shape formation. Finite element analysis was used to select appropriate variables for back-pressure formation to generate ribs of various sizes and shapes without defects. The reliability of the analysis was verified to manufacture the prototype. The effect of back-pressure can be verified via fabrication of prototypes as well as structure and forming analysis based on finite element method. The process design factor of back-pressure increases formability without defects of under-filling and flow-through. Moreover, the tensile strength was maintained even after high temperature plate forging at 370 ℃, and the elongation was improved.

• Journal of Welding and Joining
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• v.28 no.5
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• pp.86-92
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• 2010

In GMAW processes, bead geometry is a criterion to estimate welding quality. Bead geometry is affected by welding current, arc voltage, welding speed, shielding gas and so on. Thus the welding condition has to be selected carefully. In this paper, an experimental method for the selection of optimal welding condition was proposed in the root pass welding which was done along the GMA V-grooved butt weld joint. This method uses the response surface analysis in which the width and height of back bead were chosen as the quality variables of the weld. The overall desirability function, which is the combined desirability function for the two quality variables, was used as the objective function for getting the optimal welding condition. Through the experiments, the target values of the back bead width and the height were chosen as 4mm and 1mm respectively for the V-grooved butt weld joint. From a series of welding test, it was revealed that a uniform weld bead can be obtained by adopting the optimal welding condition which was determined according to the method proposed.

• Journal of Adhesion and Interface
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• v.18 no.2
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• pp.59-67
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• 2017

Recently, integration of parts is accelerating according to the growth of the smart mobile industry. The integration of these parts causes problems of interference phenomena between the parts, and the importance of electromagnetic wave shielding technology to solve this problem is highlighted. Electromagnetic wave shielding technology is implemented so as to reflect or absorb electromagnetic waves, and generally conductive materials are utilized for electromagnetic wave shielding. Transparent shielding technology is required according to recent industrial changes. In this research, we propose transparent the shielding film using imprint technology with conductive composite binder. Utilizing UV polymerized acrylic binder to produce a conductive composite binder. Spherical, plate and stacked silver particles were used for conductivity. The changes of the curing characteristics, conductivity and adhesion were observed according to the structural characteristics of the silver particles. The use of spherical particles was the most efficient in the curing process, and an additional curing system was required to complement the UV-shadowing structure. In the conductivity evaluation, the stacked structure showed excellent characteristics. The adhesion of spherical system was the best. It is evaluated as a result of irregularities on the surface. Ultimately, the patterned film using this showed excellent transparency characteristics.

• Journal of the Korean Society of Radiology
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• v.15 no.2
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• pp.109-115
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• 2021

This study is a study on the difference in dose according to the presence or absence of gonadal shielding of scattered rays generated during chest computed tomography examination, and the scattered dose of the examination site was measured by placing the RadEye G-10 device in the center of the phantom. When the gonads are not shielded, the scattering lines of the whole, both sides, posterior and gonads are measured and Xenolite nolead Apron (0.35 mm PB), Xenolite nolead Apron (front 0.35 mm PB Mix back 0.25 mm PB, Skirt overlap), Half Apron After shielding with (0.5 mm PB), each scattered dose was measured. During chest computed tomography, the scattered dose of the test site was measured at 272 μSv, and when not shielded with Apron, the average total was 43 μSv, left 81 μSv, right part 82 μSv, posterior part 38.8 μSv, and Gonad part 16 μSv. Became. Xenolite nolead Apron shielded only the upper part and measured all 11.2 μSv, left part 43.1 μSv, right part 45.3 μSv, posterior part 12 μSv and Gonad part 5.2 μSv. Xenolite nolead Apron (Skirt overlap) covered the Pelvis area 360° and the dose was measured to be 5.6 μSv in the whole, 22.4 μSv in the left, 15.7 μSv in the right side, 6 μSv in the posterior part, and 3.2 μSv in the Gonad part. Xenolite nolead Apron (Skirt overlap) covered the Pelvis area 360° and the dose was measured to be 5.6 μSv in the whole, 22.4 μSv in the left, 15.7 μSv in the right side, 6 μSv in the posterior part, and 3.2 μSv in the Gonad part. When measuring only the upper part with Half Apron, the total measurement was 10.7 μSv, the left part 42.6 μSv, the right part 40.6 μSv, the posterior part 11.3 μSv, and the Gonad part 4.7 μSv. The method of 360° shielding of the pelvic area showed a dose reduction of more than 80%, and a dose reduction effect of more than 70% was shown when all shielding was performed. In all computerized tomography examinations, research to reduce the exposure dose and various shielding devices were used. It is believed that continuous research on the technique is needed.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.4
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• pp.426-433
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• 2014

The high-altitude electromagnetic pulse(HEMP) generated by a high-altitude nuclear explosion. This paper presents the comparison of electric field penetration in Bell laboratories and IEC 61000-2-9 standard when HEMP source penetrates through Naval Warship conducted coupling path and radiated coupling path. Also we analyze the effects of two kinds of coupling and propose Protective measures. Simulation results confirm IEC 61000-2-9 standard is more strict than the Bell Laboratories standard except for a lower frequency band, so we proposed IEC 61000-2-9 standard as a Naval HEMP standard. Finally, we offer the protective measures such as the shielding coating, Honeycomb ventilation, TVS in order to meet the military criteria.

• Journal of radiological science and technology
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• v.43 no.3
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• pp.169-176
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• 2020

Interventional radiology is performed under real-time fluoroscopy, and patients are exposed to a wide range of exposures for a long period of time depending on the examination and procedure. However, studies on radiation protection for patients during an intervention are insufficient. This study aims to evaluate the doses exposed during the intervention and the applicability of 3D printing materials. The organ dose for each intervention site was evaluated using a monte carlo simulatio. Also, the dose reduction effect of the critical organs was calculated when using a shielding device using 3D printing materials. As a result, the organ dose distribution for each intervention site showed a lower dose distribution for organs located far from the x-ray tube. It was analyzed that the influence of scattered rays was higher in the superficial organs of the back of the human body where x-rays were incident. The dose reduction effect on the critical organ using the 3D printing shield showed the highest testis among the gonads, and in the case of other organs, the dose reduction effect gradually decreased in the order of the eye, thyroid, breast, and ovary. Accordingly, it is judged that the 3D printed shield will be sufficiently usable as a shielding device for the radiation protection of critical organs.

• Proceedings of the Korean Society of Laser Processing Conference
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• 2006.11a
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• pp.17-20
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• 2006

In the remote welding system using $CO_2$ laser, laser beam is rapidly deflected by moving mirrors of scanner system and has focusable distance over 1000mm from workpiece. From such arrangement, various advantages and disadvantages arise. Remote welding is a highly efficient laser process. As the mirrors of the scanner system allow positioning speeds exceeding 700m/s, it becomes possible to reduce the welding cycle time. On the other hand, as there no the provision of shielding gas which is normally required for beam powers exceeding 3kW, may become difficult task. Therefore, In this study, the influence of the various penetration of back bead by the different laser welding speed on the weld seam formation without shielding gas was investigated.

• Proceedings of the KWS Conference
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• 2005.11a
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• pp.171-173
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• 2005

Inconel 617 is a solid solution, nickel-chromium-cobalt-molybdenum alloy with an exceptional combination of high temperature strength and oxidation resistance. The combination of high strenth and oxidation resistance at temperatures over $1800^{\circ}F$ makes Inconel 617 an attractive material for such components as ducting, transition liners in both aircraft and gas turbine. In this study, the weldability and weldment characteristics of Inconel 617 are considered in GTAW associated with the two welding current and with back shielding gas using or not. After GTAW with 120A and 150A current, microstructures and hardness test, bending test, tensile test on room and elevated temperature for the determination of optical welding condition.