• Journal of Dental Rehabilitation and Applied Science
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• v.36 no.4
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• pp.282-288
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• 2020

Radiation prosthetic stent is defined as the customized oral devices which serve for an efficient administration of radiation dose to the affected areas or a minimizing the unnecessary irradiation to surrounding normal tissues during maxillofacial cancer radiotherapy. Since the use of stents is individualized, a close collaboration among radiotherapist, surgeon and prosthodontist is essential thereby which helps in limiting the post-therapy morbidity as well as the stable oral rehabilitation. In this report, two customized stents (bolus carrier and tongue depressing) were fabricated and applied to patient undergone irradiation for soft palate and tongue carcinoma selectively. Multidisciplinary approach can be a proper strategy and recommended for control the sequel of post-irradiation.

• Nuclear Engineering and Technology
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• v.54 no.6
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• pp.2198-2203
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• 2022

As robotics become more sophisticated, there are a growing number of generic systems being used for routine tasks in nuclear environments to reduce risk to radiation workers. The nuclear sector has called for more commercial-off-the-shelf (COTS) devices and components to be used in preference to nuclear specific hardware, enabling robotic operations to become more affordable, reliable, and abundant. To ensure reliable operation in nuclear environments, particularly in high-gamma facilities, it is important to quantify the tolerance of electronic systems to ionizing radiation. To deliver their full potential to end-users, mobile robots require sophisticated autonomous behaviors and sensing, which requires significant computational power. A popular choice of computing system, used in low-cost mobile robots for nuclear environments, is the UP Core single board computer. This work presents estimates of the total ionizing dose that the UP Core running the Robot Operating System (ROS) can withstand, through gamma irradiation testing using a Co-60 source. The units were found to fail on average after 111.1 ± 5.5 Gy, due to faults in the on-board power management circuitry. Its small size and reasonable radiation tolerance make it a suitable candidate for robots in nuclear environments, with scope to use shielding to enhance operational lifetime.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.9
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• pp.1351-1358
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• 2017

In this work, we investigated radiation hardness of GaN-based transistors which are strong candidates for next-generation power electronics. Field effect transistors with three types of gate structures including metal Schottky gate, recessed gate, and p-AlGaN layer gate were fabricated on AlGaN/GaN heterostructure on Si substrate. The devices were irradiated with energetic protons and alpha-particles. The irradiated transistors exhibited the reduction of on-current and the shift of threshold voltage which were attributed to displacement damage by incident energetic particles at high fluence. However, FET operation was still maintained and leakage characteristics were not degraded, suggesting that GaN-based FETs possess high potential for radiation-hardened electronics.

• Journal of Radiation Protection and Research
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• v.26 no.3
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• pp.243-248
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• 2001

Neutron reference fields of Korea Atomic Energy Research Institute (KAERI) for calibrating neutron measuring devices to be used in radiation workplace monitoring consist of two kinds of neutron spectra, the direct and the scattered neutron fields, which are produced by using radionuclide neutron sources, 252Cf and 241AmBe sources. Necessary parameters for calibration such as the anisotropy factor of each neutron source and the room-scattered fraction of some neutron surveymeters in the KAERI calibration facility were determined by calculation or measurement. Spectral measurement of scattered neutron fields were performed at each reference calibration point using a Bonner Multi-sphere Spectrometer (BMS) and the dosimetric quantities for calibration also estimated from the neutron energy spectra which were unfolded using the BUNKI code.

• Macromolecular Research
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• v.14 no.4
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• pp.473-477
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• 2006

The above described semi-transparent monochromators have been operational since 1997. Four units are permanently operating at the ESRF beam line ID14. Two units are in continuous operation at ID 10 and one unit is installed at the APS beamline 8-ID in USA. The water cooling of the crystals is currently being revised and above we showed that improvements most likely are possible by using micro fluidics techniques. Further tests will be performed in collaboration with the CEA-France and tested at ESRF. Parallel developments including nanofluids as coolants are under evaluation. Combination of nanofluidics and microfluidics cooling devices are under study. The authors are grateful to C. Gillot and J-A. Gruss for useful discussions and advices, and to S.Mcheik for his work on the thermal model.

• Journal of the Korean Solar Energy Society
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• v.31 no.5
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• pp.27-32
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• 2011

Most of domestic building generally don't have fixed shading devices considering of appearance and aesthetic issues. In this study is suggested that tilt window simultaneously has a role of shading and blocking solar radiation. The tilt window thermal performance is investigated by relation ship between inclination and heating cooling road. As comparing vertical window with $5^{\circ}$ and $7^{\circ}$ of tilt window respectively, the heating load is increased by 3.6% and cooling load is reduced by 8.1% on $5^{\circ}$ tilt window and the heating load is increased by 5.3% and cooling load is reduced by 11.5% on $5^{\circ}$ tilt window. Especially, the total load of alternative tilt window is showed the reduction rate 2.6% and3.6% compared of vertical window. Therefore, the tilt window is possible to role of shading of solar radiation and reduction of heating and cooling load.

• ETRI Journal
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• v.41 no.4
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• pp.528-535
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• 2019

The coupling mechanism of a loop-type ground radiation antenna is investigated in this paper. We use the equivalent circuit model of the antenna and a full-wave simulation to explain the coupling mechanism of the antenna. We analyze the effects of various antenna parameters on the coupling between the antenna element and the ground plane to examine the conditions for enhancing the coupling. Based on simulations with the equivalent circuit model, full-wave simulations, and measurements, we propose optimal design considerations for the antenna. The findings of this study will aid the design and understanding of loop-type ground radiation antennas for mobile devices.

• Electronics and Telecommunications Trends
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• v.37 no.2
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• pp.21-29
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• 2022

Cosmic radiation environments having extremely high-energy particles and photons cause severe malfunctions of electrical components in space and terrestrial regions. In this study, we revisit basic knowledge on radiation effects in ICT electrical devices, such as single event effect, total ionizing dose, and displacement damage. To avoid such soft errors and system failures, we introduce essential technical approaches from the perspectives of materials, layouts, circuits, and systems, including current research trends. By considering several techniques and Space EEE part standards, we suggest possible directions that can invoke New Space Era technology.

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.92.1-92
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• 1998

• The Journal of Korean Society for Radiation Therapy
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• v.9 no.1
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• pp.64-70
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• 1997

The goal of radiation treatment planning is to deliver the dose to the patient within $5\%$ of that prescribed. We have often encountered the situation that the area which have not only several irregular contours but also tissue heterogeneities should be treated. With conventional devices such as wedges, missing tissue compensator. there are some limitations to achieve the uniform dose distribution in treatment volume. The use of CT simulator, 3-D planning system, computer-controlled milling machine enables it to deliver the dose uniformally. This report includes the whole procedure which have patient data acquisition 3D planning, computer-controlled milling, performance verification of 3D compensator, and TLD evaluation. We applied it for the treatment of head and heck cancer only. In Spite of the irregular contour and different electron density of tessue, we have achieved the uniformity of the dose distribution within ${\pm}3\%$ relatively. Although there are some problems which are not only verification of performance but uncertainties of using the new treatment device, we believe that the improvement of dosimetry will eliminate the uncertainties of that application. so the other lesions besides head and neck can will be ale to use the 3D compensator to achieve the dose uniformity