• The Journal of the Korea institute of electronic communication sciences
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• v.10 no.3
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• pp.333-340
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• 2015

In this paper, we propose a passive microwave sensor for detecting human body using microwave radiometer technologies. The proposed sensor detects human body by measuring the change of the received radiation power from fixed background object due to human body. A C-band microwave radiometer is designed and implemented. The received radiation power changes due to human body is measured by the C-band microwave radiometer, and the effectiveness of the proposed sensor is evaluated by the measurement result analysis.

• Journal of Radiation Protection and Research
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• v.20 no.3
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• pp.155-162
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• 1995

The state-of-the art of detection and measurements of non-ionizing radiations are reviewed in relation to protection requirements, especially for electromagnetic and ultraviolet radiations. Dosimetric quantities, instruments and considerations needed for measurement are briefly explained. For electromagnetic radiation, the power density levels from various practical sources are summarized for reference uses. Large errors remain in the measurements of non-ionizinf radiations in general. Technical needs of development in measurement and dosimetry of non-ionizing radiations, therefore, are promissing when the increasing public concerns about the adverse health effects of non-ionizing radiations and proliferation of their uses are taken into account.

• Journal of Radiation Protection and Research
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• v.27 no.1
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• pp.51-57
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• 2002

An electronic personal dosimeter(EPD) with hybrid type preamplifier adopting a semiconductor detector as a radiation detector has been developed, manufactured and test-evaluated. The radiation detection characteristics of this EPD has been performance-tested by using a reference photon radiation field. After several test-irradiations to a $^{137}Cs$ gamma radiation source the radiation detection sensitivity of this EPD appeared to be $3.8\;cps/Gy{\cdot}h^{-1}$. The linearity of radiation response was kept within 8% of the dose equivalent ranges of $10{\mu}Sv{\sim}4Sv$ and the angular dependence was under less than 4% in angles of ${\pm}60^{\circ}$. It was confirmed that the energy response range was in $60{\sim}1,250keV$ given in the ISO standard. This EPD satisfied the international criteria for the EPD in the mechanical and the environmental performance test for 9 test categories according to IEC 61526.

• Radiation Oncology Journal
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• v.29 no.4
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• pp.269-276
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• 2011

Purpose: To determine the incidence, risk factors, and clinical characteristics of pelvic insufficiency fracture (PIF) in patients with cervical cancer. Materials and Methods: Between July 2004 and August 2009, 235 patients with non-metastatic cervical cancer were treated with definitive chemoradiation or postoperative radiotherapy. Among 235 patients, 117 (49.8%) underwent the first positron emission tomography/computed tomography (PET/CT) within 1 year after radiotherapy. The median radiation dose was 55 Gy (range, 45 to 60 Gy). Medical charts and imaging studies, including PET/CT, magnetic resonance imaging (MRI), CT. bone scintigraphy were reviewed to evaluate the patients with PIF. Results: Among 235 patients, 16 developed PIF. The 5-year detection rate of PIF was 9.5%. The 5-year detection rate of PIF in patients who underwent the first PET/CT within a year was 15.6%. The median time to development of PIF was 12.5 months (range, 5 to 30 months). The sites of fracture included 12 sacroiliac joints, 3 pubic rami, 3 iliac bones, and 1 femoral neck. Eleven of 16 patients having PIF complained of hip pain requiring medications. One patient required hospitalization for pain control. The significant risk factors of PIF were old age, body mass index less than 23, bone mineral density less than -3.5 SD, and the first PET/CT within a year after radiotherapy. Radiation dose and concurrent chemotherapy had no impact on PIF rate. Conclusion: PIFs were not rare after pelvic radiotherapy in cervical cancer patients in the era of PET/CT. Timely diagnosis and management of PIF can improve quality of life in patients with cervical cancer, in addition to reducing unnecessary medical expenses.

• Journal of Radiation Industry
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• v.5 no.4
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• pp.297-303
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• 2011

The purpose of this research is to detect whether agricultural products were electron beam irradiated or non-irradiated by chemical methods according to increase of storage period. The three fat-rich samples including soybean, walnut, and sesame were chosen as agricultural products, and then were irradiated with doses of 1~10 kGy by using 10 MeV electron beam facility. At the result, 8-heptadecene and 1,7-hexadecadiene, which are indicators of electron beam-irradiation in chemical methods by gas chromatography/mass spectrometry(GC/MS) method, were detected in all three samples. The levels of two irradiation indicators were increased by electron beam-irradiation in a dose-dependent manner. Furthermore, two irradiation indicators also were detected in all samples in 6 and 12 months after irradiation, though levels of those were decreased in a time-dependent manner. These results mean that the quantification of 8-heptadecene and 1,7-hexadecadiene could determine whether electron beam were irradiated or non-irradiated until 12 month after irradiation in 3 fat-rich agricultural products including soybean, walnut, and sesame.

• Journal of Radiation Industry
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• v.6 no.3
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• pp.239-244
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• 2012

This study was conducted to investigate bacterial growth, viscosity, color, and sensory properties of gamma-irradiated Tarakjuk powder, a Korean milk porridge powder, at 1, 3, 5, 7, and 10 kGy. The total aerobic bacteria in non-irradiated Tarakjuk powder was $2.56{\log}\;CFU{\cdot}g^{-1}$, whereas it was not observed within the detection limit of $2{\log}\;CFU{\cdot}g^{-1}$ in samples irradiated at more than 1 kGy. Spore-forming bacteria, however, were not observed in all samples within the detection limit of $1{\log}\;CFU{\cdot}g^{-1}$. The viscosity of rehydrated Tarakjuk after gamma irradiation significantly decreased from 16,770 cP to 4,060 cP when irradiated at 10 kGy. The redness ($a^*$ value) and yellowness ($b^*$ value) evaluated using a colorimeter were significantly increased according to the increase in irradiation dose (p<0.05), while there was no difference in color evaluation conducted by panels. The overall acceptance decreased as the irradiation dose increased, and the 5 kGy sample was 4.0 (normal) on a 7-point scale. As a result, it is considered that a gamma irradiation of 5 kGy is enough to sterilize Tarakjuk powder with a acceptable sensory quality.

• Journal of the Korean Institute of Gas
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• v.1 no.1
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• pp.113-119
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• 1997

The detection capability of UV flame detector in dust environment would be impaired. In this study, an experiment was conducted, in an effort to further understand the behavior of UV flame detector and to evaluate its detection capability in industry dust environment. Detergent powder, coal powder and dry extinguishing agent were selected as dust sources. Flaming sources include propane and gasoline flame. Experiment results indicate that dust can cause remarkable attenuation of UV flame radiation. The concentration of dust and the length of air layer where dust dispersed determine the reduction of radiation intensity. On the other hand, the attenuation of UV radiation also depends on the chemical and Physical properties of dust.

• Preventive Nutrition and Food Science
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• v.6 no.2
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• pp.91-95
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• 2001

Competitive indirect enzyme linked immunosorbent assay (Ci-ELISA) was used to obtain the preliminary data for the detection of irradiated beef. Ci-ELISA was individually formatted with polyclonal antibodies produced from 2 kinds of bovine proteins, myosin and bovine serum albumin (BSA). Beef round, loin and tender loin were vacuum-packaged and subdivided into 3 groups of 1) irradiation; 2) irradiation and chilled at 4$^{\circ}C$ for 7 day; 3) irradiation and frozen at 2$0^{\circ}C$ for 2 months to observe the changes under different storage and/or distribution conditions. Irradiation was performed at 3, 5 and 7 kGy. Protein solutions prepared from the sample were tested by formatted Ci-ELISA. Detected concentrations of myosin and BSA decreased with the increased irradiation dose in all samples with different reduction rates. Myosin was more susceptible to freezing than BSA. Samples irradiated at 5 kGy or above could be differentiated from non-irradiated ones by Ci-ELISA. These results indicate that immunological assay can be used as a detection method for irradiated beef.

• Nuclear Engineering and Technology
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• v.53 no.12
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• pp.4072-4079
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• 2021

This article presents a study on the state-of-the-art methods for automated radioactive material detection and identification, using gamma-ray spectra and modern machine learning methods. The recent developments inspired this in deep learning algorithms, and the proposed method provided better performance than the current state-of-the-art models. Machine learning models such as: fully connected, recurrent, convolutional, and gradient boosted decision trees, are applied under a wide variety of testing conditions, and their advantage and disadvantage are discussed. Furthermore, a hybrid model is developed by combining the fully-connected and convolutional neural network, which shows the best performance among the different machine learning models. These improvements are represented by the model's test performance metric (i.e., F1 score) of 93.33% with an improvement of 2%-12% than the state-of-the-art model at various conditions. The experimental results show that fusion of classical neural networks and modern deep learning architecture is a suitable choice for interpreting gamma spectra data where real-time and remote detection is necessary.

• Nuclear Engineering and Technology
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• v.53 no.2
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• pp.618-625
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• 2021

In this paper, the single-photon avalanche diodes (SPADs) featuring three different p-well implantation doses (∅_p-well) of 5.0 × 10¹², 4.0 × 10¹², and 3.0 × 10¹² atoms/cm² under the identical device layouts were fabricated and characterized to evaluate the effects of field enhanced mechanisms on primary dark pulses due to the maximum electric field. From the I-V curves, the breakdown voltages were found as 23.2 V, 40.5 V, and 63.1 V with decreasing ∅_p-well, respectively. By measuring DCRs as a function of temperature, we found a reduction of approximately 8% in the maximum electric field lead to a nearly 72% decrease in the DCR at V_ex = 5 V and T = 25 ℃. Also, the activation energy increased from 0.43 eV to 0.50 eV, as decreasing the maximum electric field. Finally, we discuss the importance of electric field engineering in reducing the field-enhanced mechanisms contributing to the DCR in SPADs and the benefits on the SPADs related to different types of radiation detection applications.