• Korean Journal of Digital Imaging in Medicine
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• v.15 no.2
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• pp.13-18
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• 2013

Purpose : Fluoroscopy equipment, depending on the type of changes that occur in the patient's position ESD and study the patient's scatter ray of ESD Practitioners considered a comparative analysis was to evaluate the correct dose. Materials and Methods : HITACHI four overtube type TU-8000 Flat Detector and Under tube C-Arm Philips' Multi Diagnost Eleva with Flat Detector type were measured by. Each devices is a measure of the patient's esd randophantom position in tabel unfors Xi multi funtion then fixed to the abdomen fluoroscopy and 10 seconds, spot was measured three times, practitioners of the incident surface dose by considering the patient's scatter ray of the table for each device in the average human stomach 21cm thickness acrylic phantom ($25cm{\times}25cm$) Place the practitioner position after position randophantom unfors Xi multi funtion in the thyroid and stomach 1 minute by a fixed one-time fluoroscopy and measured. Results : 10 seconds and the patient perspective of the c-arm ESD 1.2 times smaller on the AP and oblique measurements were measured in the 6-13 times smaller. spot positions to changes in the measured three times on the AP of the abdomen, ESD is 18 times smaller c-arm measurements and the oblique measurement was 19-30 times smaller. And 1 minute at practitioners fluoroscopy esd in the thyroid 2.12 times the c-arm, chest 1.75 times less the dose was measured. On the AP, depending on the device, but the lack of dose difference oblique positions of the two devices depending on changes in the area due to changes in both the AP than on the dose increased, the difference in dose between the two devices, the maximum difference was approximately 27 times. Conclusion : Fluoroscopic equipment at the time of inspection in accordance with changes in dose according to the patient and the patient's positions changes, because the area of the scatter ray considering the change of dose measurements be made, and study of the equipment according to the characteristics of the efficiency and the exposure of the patient and practitioner is considered smooth study equipment manufacturers that can be done is to build the system and think that is also important. Various fluoroscopy when you check future changes in many factors of change in dose for the equipment in the laboratory system by considering the scatter ray radiation shielding for the management to take advantage of reckless undertube have been utilized as more exposure Reduction activities can help is considered as the direction.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.9
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• pp.418-424
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• 2017

Magnesium has a higher specific strength than other metals and is widely used industry wide due to its excellent vibration absorption ability and electromagnetic wave shielding property.For example, it is used for automobile parts such as car seat frames and cylinder heads, and is widely used in electronic products such as notebook cases and mobile phone cases. In addition, it is in the spotlight as a bone-implant material used to assist in the treatment of damaged bones when the bones are cracked or broken. Currently, Ti alloy, stainless steel and Co-Cr-Mo alloy are used as the implant material, and the Mg alloy remains in research stage. The current problem with bone implant implants is that the patients must undergo reoperation to remove the implants after joint surgery. Magnesium, however, can achieve sufficient strength compared to current materials. In addition, since it is self-decomposed after the recovery, reoperation is not necessary. In this paper, Mg alloys were designed by adding harmless Ca and Zn to the human body. In order to improve the strength and corrosion resistance, the final alloy was designed by adding a small amount of Sr as a grain refiner. The radioactive elements of Sr are harmful to the human body, but other naturally occurring Sr elements are harmless. Microstructure analysis of the alloys was performed by optical microscopy and scanning electron microscopy. The mechanical properties and corrosion characteristics were evaluated by tensile test, potentiodynamic test and immersion test.

• The Journal of the Korea Contents Association
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• v.14 no.8
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• pp.233-242
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• 2014

The purpose of this study is to compare the reduction of the dose radioactivity by CARE kV with that of the Bismuth shielding. First, CT was performed with transparent materials, including a Bismuth shielder which is a well-known material for decreasing the dose of radiation. Moreover, we have estimated and compared the affects of the reduction of dose on eye lens, thyroid, breast and genitals. These steps aim to compare reactions with and without the application of the Rando phantom with PLD as well as with CARE kV or not. As a result, during the Brain angio scan, the dose of CARE kV set inspection test methods showed the least dose. Depending on whether we use CARE kV, which showed the effect of dose reduction by 63%. During the Carotid angio scan, the dose was increased by 13% by how to set CARE kV+Bismuth. During the Cardiac angio scan, which showed the effect of dose reduction by 31% by how to set CARE kV+Bismuth. During the Lower extremity angio scan, the dose was measured least by how to set up the whole Bismuth. Compared with CARE kV set of test methods, which showed the effect of dose reduction by 9%.

• Polymer(Korea)
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• v.24 no.2
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• pp.268-275
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• 2000

We investigated the effect of polymer sublayer on volumetric resistivity and tensile strength of carbon fiber (CF)/polyethylene composite films fabricated under high intensity electric fields. The dependence of volumetric resistivity and tensile strength of the films on the polymer sublayer thickness or mass part exhibited complex behavior according to CF content and CF layer density in the films. As the thickness of polymer sublayer increases, two groups of processes at thermo-mechanical forming stage would take effects in the properties of the films. The first group comprises the increase of polymer layer thickness having reduced CF content compared with central or upper part of the film and insufficient wetting of CF resulting in the loosened structure near upper film side. The second group, on the other hand, is the improvement of mobility of molten sublayer leading to better distribution of CF throughout the film thickness and the formation of more compact structure. The different degree of contribution of these two competing processes at varied CF content and CF layer density could explain complex dependence of the film properties on the polymer sublayer. These results are important to optimize the electrical and mechanical properties of highly conductive polymer films, which can be used as electromagnetic interference shielding materials.

• Journal of Oral Medicine and Pain
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• v.37 no.4
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• pp.251-256
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• 2012

With today's heightened interest in quality of life, leisure and sports activities were popular in the general public. Accordingly, the incidence of oral and maxillofacial injury are also rising. Use of a mouth protector to prevent the trauma of the oral and maxillofacial region is growing in importance, and among the mouth protector the mouthguard is the most commonly used. Mouthguard has been suggested to protect injuries by (1) preventing tooth injuries by absorbing and deflecting blows to the teeth; (2) shielding the lips, tongue, and gingival tissues from laceration; (3) preventing opposing teeth from coming into violent contact; (4) providing the mandible with resilient support, which absorbs an impact that might fracture the unsupported angle or condyle of the mandible; (5) preventing neck and cerebral brain injuries. Although mouthguard is effective for prevention of oral and maxillofacial injury, it is not widespread to athletes or general public and they are lack of awareness about the importance of mouthguard. We present the types and materials of mouthguard, things to consider when mouthguard fabrication, and the usage. This should be helpful in awareness about the importance and popularization of mouthguard.

• Geophysics and Geophysical Exploration
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• v.18 no.3
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• pp.154-161
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• 2015

For efficiently designing neutron induced gamma spectroscopy sonde, Monte Carlo simulation is employed to understand a dominant location of thermal neutron and classify the formation elements from the energy peak of capture gamma spectrum. A pulsed neutron generator emitting 14 MeV neutron particles was used as a source, and flux of thermal neutron was calculated from the twelve detectors arranged at each 10 cm intervals from the source. Design for reducing borehole effects using shielding materials was also applied to numerical sonde model. Moreover, principal elements and quantities of numerical earth models were verified through the energy spectrum analysis of capture gamma detected from a gamma detector. These results can help to enhance the signal-to-noise ratio, and determine an optimal placement of capture gamma detectors of neutron induced gamma spectroscopy sonde.

• Proceedings of the KWS Conference
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• 2010.05a
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• pp.51-51
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• 2010

Recently just as in the automobile industry, shipbuilders also try to reduce material consumption and weight in order to keep operating costs as low as possible and improve the speed of production. Naturally industry is ever searching for welding techniques offering higher power, higher productivity and a better quality. Therefore it is important to have a details research based on the various welding process applied to steel and other materials, and to have the ability both to counsel interested companies and to evaluate the feasibility of implementation of this process. Submerged-arc welding (SAW) process is usually used about 20% of shipbuilding. Similar to gas metal arc welding(GMAW), SAW involves formation of an arc between a continuously-fed bare wire electrode and the work-piece. The process uses a flux to generate protective gases and slag, and to add alloying elements to the weld pool and a shielding gas is not required. Prior to welding, a thin layer of flux powder is placed on the work-piece surface. The arc moves along the joint line and as it does so, excess flux is recycled via a hopper. Remaining fused slag layers can be easily removed after welding. As the arc is completely covered by the flux layer, heat loss is extremely low. This produces a thermal efficiency as high as 60% (compared with 25% for manual metal arc). SAW process offers many advantages compared to conventional CO2 welding process. The main advantages of SAW are higher welding speed, facility of workers, less deformation and better than bead shape & strength of welded joint because there is no visible arc light, welding is spatter-free, fully-mechanized or automatic process, high travel speed, and depth of penetration and chemical composition of the deposited weld metal. However it is difficult to application of thin plate according to high heat input. So this paper has been focused on application of the field according to SAW process for thin plate in ship-structures. For this purpose, It has been decided to optimized welding condition by experiments, relationship between welding parameters and bead shapes, mechanical test such as tensile and bending. Also finite element(FE) based numerical comparison of thermal history and welding residual stress in A-grade 3.2 thickness steel of SAW been made in this study. From the result of this study, It makes substantial saving of time and manufacturing cost and raises the quality of product.

• Journal of Korean Society of Water and Wastewater
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• v.18 no.3
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• pp.392-400
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• 2004

This research uses the $TiO_2$/UV process to verify the most suitable condition and possibility to dispose dyeing wastewater that contains pigment and a large amount of pollutants. For this, this research has enforced experiments that compare photo adsorption, photolysis, and photo catalyst oxidation reaction, and also evaluated and analyzed the change of pH and $TiO_2$ dosage, irradiation rates of ultraviolet rays and the dosage change and injection method of $H_2O_2$. According to the results of the dyeing wastewater experiment of storehouse catalyst that uses the new form of $TiO_2$, the photo catalyst oxidation reaction proved to be more effective than photo adsorption and photolysis; 35%, 21% in the case of $TCOD_{cr}$ and 39%, 28% in the case of chromaticity. Taking into consideration the reaction time, amount of photo catalyst reaction and irradiation amount of ultraviolet rays, the decomposition efficiency of pH change proved to be most effective at pH 4. On the whole, the acidity area proved to be effective in dyeing water exclusion than neutral and alkalinity areas. Having evaluated the influence of $TiO_2$ dosage, not only does the decomposition efficiency continuously improve as the $TiO_2$ dosage increases but the shielding effect does not occur also when the $TiO_2$ is at a fixed state. The influence of ultraviolet irradiation amount concluded in the result that as the ultraviolet irradiation amount increases the decomposition efficiency continually increased, but in the case of chromaticity when the irradiation amount was higher than 37.8mW/cm2 the removal efficiency is slowed remarkably. The influence of $H_2O_2$ dosage evaluation reached the results that although the decomposition efficiency increases with the increase of $H_2O_2$ dosage, when above 150mg (total dosage: 1200mg) $H_2O_2$ consumes OH radical itself and reduces the decomposition efficiency. Also in the case of the $H_2O_2$ injection method rather than injecting in the whole amount of $H_2O_2$ (1200mg) needed at the beginning all at once, injecting divided quantities of $H_2O_2$ whenever the electric current density falls below 10mgfl reduces the wases of OH radical due to an excess of $H_2O_2$ and in tum heightens the decomposition efficiency.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.6
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• pp.644-653
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• 2013

In this paper, a formulation for obliquely incident electromagnetic wave has been presented for an analysis of highpower electromagnetic pulse penetration into multilayered dispersive media. Based on generalized models of measured dielectric constants and propagation channels reflecting the Earth's general features, the propagation phenomenon of the obliquely incident early-time(E1) high altitude electromagnetic pulse(HEMP) is analyzed. In addition, the polarization and critical angle are also considered. It is found that the total reflection occurs at an incident angle of about 38 degrees at the soil-rock interface, and that the parallel-polarized E1 HEMP penetrates better than the perpendicular-polarized one. The peak level of the penetrating electric field is found to be 5.6 kV/m at normal incidence, regardless of the type of polarization, and E1 HEMP is greatly reduced near the critical angle. Moreover, the penetrating E1 HEMP is analyzed as a variation of moisture content and depth of materials, resulting E1 HEMP could be useful in determining the levels of shielding required for buried facilities.

• Journal of Radiation Protection and Research
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• v.9 no.2
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• pp.90-96
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• 1984

Estimated dose rates in spent fuel pool storage with the extended fuel cycle core management were reviewed and compared with design limit after calculation with the aid of DLC-23/CASK(22 n, 18 g) nuclear data and ANISN code. Radioactivity and gamma spectrum within spent fuel assemblies were calculated with ORIGEN code by extended fuel cycle model. In the calculation of dose rate, the fuel pool geometry was assumed to be infinite slab. Also, composition materials and radiation source within assemblies which are being stored in pool storage were assumed to be uniformly distributed throughout all the assemblies. As a result of culculation of dose rate from stored assemblies and waterborne radionuclides in pool water, the calculated dose rates appear to be lower than design basis limit under normal condition as well as abnormal condition.