• Nuclear Engineering and Technology
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• 제50권5호
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• pp.690-697
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• 2018

Criticality alarm systems (CASs) are mandatory in nuclear plants for prompt alarm in the event of any criticality incident. False criticality alarms are not desirable as they create a panic environment for radiation workers. The present article describes the design enhancement of the CAS at each stage and provides maximum availability, preventing false criticality alarms. The failure mode and effect analysis are carried out on each element of a CAS. Based on the analysis, additional hardware circuits are developed for early fault detection. Two different methods are developed, one method for channel loop functionality test and another method for dose alarm test using electronic transient pulse. The design enhancement made for the external systems that are integrated with a CAS includes the power supply, criticality evacuation hooter circuit, radiation data acquisition system along with selection of different soft alarm set points, and centralized electronic test facility. The CAS incorporating all improvements are assembled, installed, tested, and validated along with rigorous surveillance procedures in a nuclear plant for a period of 18,000 h.

• Radiation Oncology Journal
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• 제7권2호
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• pp.157-169
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• 1989

Radiological and clinical evidences indicate that hyperthermia combined with irradiation produce a significant improvement in therapeutic effect of cancer The experiences obtained from 90 rats' kidney A single dose of irradiation ranged from 6Gy, 8Gy and 10Gy was delivered on the rat's kidney. The combined therapy group had the same irradiation after hyperthermia at $42\~44^{\circ}C$ for 30 minutes. Microscopic examination and calculation of thermal enhancement ratio were carried out, and the results were as follows: 1. In the group of hyperthermia alone, there were moderate glomerular congestion and mild tubular degeneration on light microscopic examination. 2. In the group of irradiation alone, tubular degeneration was noted in 6Gy irradiation and its severity was increased along with radiation dose. 3. In the group of hyperthermia combined with irradiation, tubular degeneration and necrosis were appeared in 6Gy and 10Gy irradiation, respectively. 4. On electron microscopic examination, proximal convoluted tubular and glomerular changes in irradiation group were similar to that of combined with hyperthermia, and its severity was increased along with observation periods. 5. Thermal enhancement ratio (TER) was 1.0 after evaluation of histipathologic changes in rat's kidney, with combination therapy.

• Nuclear Engineering and Technology
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• 제56권2호
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• pp.666-672
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• 2024

In the present work, a new brick series based on the Vietnamese white clay minerals from the Bat Trang was fabricated to be applied in the radiation protection applications during the decommissioning of the nuclear power reactors. The bricks were constructed under various pressure rates varied from 7.61 MPa to 114.22 MPa. The influence of pressure rate on the physical and γ-ray shielding properties were investigated in the study. The experimental measurement for the material's density using the MH-300A density meter showed an enhancement in the prepared bricks' density by 22.5 % with increasing the applied pressure rate while the bricks' porosity reduced by 31.2 % when the pressure rate increased from 7.61 MPa to 114.22 MPa. The increase in the fabricated bricks density and the reduction in their porosities enhances the bricks' linear attenuation coefficients as measured by the NaI (Tl) detector along the energy range extended from 0.662 MeV to 1.332 MeV. The linear attenuation coefficient increased by 13.8 %, 17.6 %, 17.0 %, and 17.1 % at gamma ray energies of 0.662 MeV, 1.173 MeV, 1.252 MeV, and 1.332 MeV, respectively. The enhancement in the linear attenuation coefficient increases the bricks' radiation protection efficiency by 10.22 %, 14.48 %, 14.09 %, and 14.26 % at gamma ray energies of 0.662 MeV, 1.173 MeV, 1.252 MeV, and 1.332 MeV, respectively.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2018년도 추계학술논문요약집
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• pp.33-34
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• 2018

• Investigative Magnetic Resonance Imaging
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• 제24권1호
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• pp.46-50
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• 2020

Radiation-induced lumbosacral plexopathy (RILSP) is an uncommon complication of pelvic radiotherapy that can result in different degrees of sensory and motor deficits. An age 59 female with cervical cancer, who had received combined chemotherapy and radiation therapy two years before, presented with bilaterally symmetric lower-extremity weakness and tingling sensation. The magnetic resonance imaging showed diffuse T2 bright signal intensity and mild enhancement along the bilateral lumbosacral plexus with no space-occupying masses. RILSP was diagnosed after the exclusion of malignant and inflammatory plexopathies.

• Journal of Advanced Marine Engineering and Technology
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• 제25권1호
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• pp.146-154
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• 2001

In almost all real situations, there will be a radiant interchange between adjacent fins with the base surface as well as with the external environment. In the problem of this study, a rectangular fin is attached to a based. Our concern is whether the convective fin efficiency can be increased by the radiation heat exchanged between the fin and the base surface and how much. If the fin temperature toward the tip increased by the effect of radiation, the convective heat transfer increase due to the temperature difference between the ambient temperature and the surface temperature of the fin. If this true, the efficiency of the fin due to the radiation will increase. Attention is directed toward several parameters which have major roles on getting values of the fin efficiencies in several different values of parameters. Many different cases are, therefore, to be examined to have maximum fin efficiency by varying the values of each parameter.

• 한국환경농학회지
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• 제21권3호
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• pp.202-207
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• 2002

참박과 호박 채종종자의 발아율을 증진시킬 수 있는 종자처리 방법을 확립하고자 저선량 감마선을 1$\sim$20 Gy 까지 조사하여 발아와 초기생육 및 생리활성을 관찰하였다. 저선량 조사한 참박과 호박종자의 발아율은 대조구보다 증가하는 경향을 보였는데 그 효과는 종자상태에 따라 다르게 나타났다. 참박 70$\sim$80% 발아율종자의 발아는 4$\sim$20 Gy에서 증가하였는데 특히 4 Gy조사에서 가장 높았고, 80$\sim$90% 발아율종자도 4 Gy 조사에서 효과를 보였다. 파종 4일 후의 발아율은 참박 70$\sim$80%와 80$\sim$90% 발아율 종자의 경우는 4 Gy조사에서 대조구보다 각각 66%와 26% 증가하였고, 호박의 70$\sim$80% 발아율종자는 2 Gy 조사에서, 80$\sim$90% 발아율종자는 8 Gy 조사에서 향상되었다. 저선량 조사한 유묘생육은 발아율이 증가한 선량에서 증가하였는데 특히 호박 70$\sim$80% 종자의 2 Gy 조사에서 가장 높았다. 파종 6일 후에 조사한 참박의 효소활성은 4 Gy 조사시에 단백질과 catalase 활성이, 호박의 경우는 catalase와 peroxidase 활성이 2 Gy와 8 Gy 조사에서 증가하였다. 참박과 호박종자의 발아와 유묘생육 및 생리활성은 저선량 감마선 조사에 의해 촉진됨을 확인할 수 있었다.

• 대한의용생체공학회:의공학회지
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• 제9권1호
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• pp.61-66
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• 1988

Because the amount of radiation emerging from the thorax behind the lungs is often literally thousands of times that exiting behind the mediastinum, the dynamic range of X-ray chest image is very large. In order to solve the dynamic range problem, we propose a signal adaptive algorithm which enhances the local contrast and contracts the enhancement of quantum noise by local mean/valiance estimator.

• Medical Lasers
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• 제10권2호
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• pp.61-67
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• 2021

Advances in nanobiotechnology have presented numerous possibilities of more effective diagnostic and therapeutic options. In particular, gold nanoparticles have demonstrated the potential for application in molecular imaging and treatment of cancers, including drug delivery system of certain target molecules, enhancement of radiation therapy, and photothermal treatment. This review discusses the properties, mechanism of action, and clinical application of gold nanoparticles. Although the safety of nanoparticles is yet to be ascertained, there is no doubt that in the future, nanotechnology will play an important role in the development and enhancement of a wide range of diagnostic and treatment modalities.

• 대한안전경영과학회지
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• 제17권4호
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• pp.193-198
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• 2015

This study analyzed the total number of 19,636 patients and radiation technologists, 11,433 of male and 8,203 of female by examined body parts, age, types of detectors, the using contrast enhancement and working condition of the technologists, regular staffs or rotation-duty staffs, based on the K-DOS program distributed by FDA with the DLP value of diagnostic evaluation. The result shows that the effective radiation dose was 0.7mSv~41.7mSv for each region and male patients had more radiation exposure than females. And the amount of exposure was also affected by the types and the method of detectors. Furthermore, the regular staffs took the role of helping the patient to get reduced amount of radiation exposure than rotation duty-staffs. Computed tomography (CT) use has increased dramatically over the past several decades. In this reason, to support the patients and the workers' health in the field, the hospitals should apply specialized regular working radiation technologist system and manufacturing companies of those CTs should develop low medical radiation exposure devices.