• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 1993년도 춘계학술대회 논문집
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• pp.3-5
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• 1993

It is very important that a spectrum of reflectance is in accord wi th a spectrum of absorbance for a effective heating. Therefore. the objective of this study was to achieve a technical composite for material plan which PTC thermistor increase a radiation property of far-infrared and keep a characteristic of R-T The Ceramic speciman studies had the composition $BaTiO_3$ with additive of 1.67 $Al_2O_3$, 3.75 $SiO_2$, 1.25 $TiO_2$, 0.15 $Sb_2O_3$ and 0.00-0.182 $MnO_2$. $MnO_2$ amounts of additives was both increase on the anomalous resistivity-temperature characteristics and high efficiency on the radiation properties bodies of far-infrared. This result shows that specimens produced high emissivity(average 0.8) of far-infrared at 4.5-15$[{\mu}m]$ by measuring a characteristic of IR and R-T.

• Journal of The Korean Astronomical Society
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• 제25권2호
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• pp.111-128
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• 1992

Infrared emissions from spherical dust, clouds are calculated using quasi-diffusion method. We have employed graphite-silicate mixture with power-law size distribution for the dust model. The grains are assumed to be heated and cooled by radiative processes only. The primary heating source is diffuse interstellar radiation field. hut the cases with an embedded source are also considered. Since graphite grains have higher temperature than silicate grains, the observed IR emission is mainly due to graphite grains, unless the fraction of graphite grains is negligibly small. The color temperature of Bok globules obtained from IRAS 60 and $100{\mu}m$ data are found to be consistent with the dust cloud with graphite-silicate mixture exposed to average interstellar radiation field. The color temperature is sensitive to the external radiation field, but rather insensitive to the size distribution of the grains. We found that the density distribution can be recovered outside the beam size using the inversion technique that assumes negligible optical depth. However, the information within the beam size is lost for if beam convolved intensity distributions are used in deriving density profile.

• Nuclear Engineering and Technology
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• 제50권1호
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• pp.211-215
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• 2018

Chitosan was modified by gamma radiation-induced grafting with maleic acid and then used for the removal of cobalt ions from aqueous solutions. Chitosan-g-maleic acid was characterized by Fourier Transform infrared spectroscopy (FT-IR). The effect of the dose (1-5 kGy) and monomer concentration (0.3-1.3%, m/v) on the grafting ratio was examined. The adsorption kinetics and isotherms were also investigated. The results showed that the optimal dose for grafting was 2 kGy. When monomer concentration was within the range of 0.3-1.3% (m/v), the grafting ratio increased almost linearly. For the adsorption of cobalt ions by chitosan-g-maleic acid beads, the pseudo second-order kinetic model ($R^2=0.99$) and Temkin isotherm model ($R^2=0.96$) were able to fit the experimental data reasonably well. The equilibrium adsorption capacity of cobalt ions increased from 2.00 mg/g to 2.78 mg/g after chitosan modification.

• Radiation Oncology Journal
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• 제29권2호
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• pp.71-82
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• 2011

Purpose: To evaluate the biochemical control rate and the rate of side effects after performing permanent brachytherapy of localized prostate cancer. Materials and Methods: 67 patients with localized prostate cancer were treated with brachytherapy between April 2007 and December 2008. Of these, 43 patients who were followed up and did not receive external radiotherapy were evaluated for the change in prostate specific antigen (PSA) level and the occurrence of side effects. In total, 18 patients were classified as low risk, 19 patients as intermediate risk, and 6 patients as high risk. The prescription dose was 145 Gy. Results: A PSA increase greater than 2 ng/mL occurred in 2 patients (4.7%). Radiation Therapy Oncology Group (RTOG) grade 1 and 2 acute urologic complications (UC) occurred in 40 and 3 patients, respectively. Further, 5 patients had RTOG grade 1 acute rectal complication (RC). The numbers of RTOG grade 1, 2, and 3 chronic UC were 1, 4, and 1, respectively. The numbers of RTOG grade 1, 2, and 4 chronic RC were 5, 10, and 3, respectively. The statistically significant risk factors (RF) of acute RC were the minimal dose in the most irradiated 0.1 cc volume ($D_{0.1cc}$, p=0.041) and absolute volume receiving 150% of the prescribed dose ($V_{150cc}$, p=0.038) in the entire rectum (ER). The percentage ($V_{100%}$, p=0.019) and absolute volume ($V_{100cc}$, p=0.047) in the involved rectum (IR) were also statistically significant. The RF of chronic RC were $V_{100%}$ (p=0.011) in the ER and the $D_{0.1cc}$ (p=0.049), $V_{100cc}$ (p=0.023) in the IR. The number of used seeds were related with acute UC (p=0.028). Conclusion: Permanent brachytherpy of localized prostate cancer showed a favorable short term biochemical control rate. As such, selective intermediate and high risk patients can be managed with permanent brachytherapy. The effort to reduce rectal complication is also necessary.

• Radiation Oncology Journal
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• 제20권3호
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• pp.283-293
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• 2002

Purpose : A PC based brachytherapy planning system was developed to display dose distributions on simulation images by 2D isodose curve including the dose profiles, dose-volume histogram and 30 dose distributions. Materials and Methods : Brachytherapy dose planning software was developed especially for the Ir-192 source, which had been developed by KAERI as a substitute for the Co-60 source. The dose computation was achieved by searching for a pre-computed dose matrix which was tabulated as a function of radial and axial distance from a source. In the computation process, the effects of the tissue scattering correction factor and anisotropic dose distributions were included. The computed dose distributions were displayed in 2D film image including the profile dose, 3D isodose curves with wire frame forms and dosevolume histogram. Results : The brachytherapy dose plan was initiated by obtaining source positions on the principal plane of the source axis. The dose distributions in tissue were computed on a $200\times200\;(mm^2)$ plane on which the source axis was located at the center of the plane. The point doses along the longitudinal axis of the source were $4.5\~9.0\%$ smaller than those on the radial axis of the plane, due to the anisotropy created by the cylindrical shape of the source. When compared to manual calculation, the point doses showed $1\~5\%$ discrepancies from the benchmarking plan. The 2D dose distributions of different planes were matched to the same administered isodose level in order to analyze the shape of the optimized dose level. The accumulated dose-volume histogram, displayed as a function of the percentage volume of administered minimum dose level, was used to guide the volume analysis. Conclusion : This study evaluated the developed computerized dose planning system of brachytherapy. The dose distribution was displayed on the coronal, sagittal and axial planes with the dose histogram. The accumulated DVH and 3D dose distributions provided by the developed system may be useful tools for dose analysis in comparison with orthogonal dose planning.

• Journal of the Korea Society of Computer and Information
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• 제20권4호
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• pp.57-67
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• 2015

The concept of detection and classification of objects based on infrared camera is widely applied to military applications. While the object detection technology using infrared images has long been researched and the latest one can detect the object in sub-pixel, the object classification technology still needs more research. In this paper, we present object classification method based on measured radiant intensity of objects such as target, artillery, and missile using infrared camera. The suggested classification method was verified by radiant intensity measuring experiment using black body. Also, possible measuring errors were compensated by modelling-based correction for accurate radiant intensity measure. After measuring radiation of object, the model of radiant intensity is standardized based on theoretical background. Based on this research, the standardized model can be applied to the object classification by comparing with the actual measured radiant intensity of target, artillery, and missile.

• Journal of the Korean Society of Radiology
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• 제16권4호
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• pp.405-410
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• 2022

In brachytherapy, a radiation source is inserted into the body to kill tumor tissue. Therefore, it is important to accurately measure the location of the source and the dose distribution. In this study, a dosimeter that can be used for brachytherapy was developed using CsPbBr₃ which is cheaper than the existing detector materials and has a simpler manufacturing process. The CsPbBr₃ dosimeter performance was evaluated by analyzing reproducibility, linearity, and distance dependence in ¹⁹²Ir source. As a result of reproducibility evaluation, the RSD was 1.36%, which satisfies the standard value of 1.5%. As a result of the linearity evaluation, the R² value was 0.9993, which satisfies the standard R² of 0.9990. The distance dependence evaluation showed a signal value that decreased exponentially as the distance increased. The evaluation results show that the CsPbBr₃ dosimeter satisfies the evaluation criteria and can be used as a brachytherapy quality assurance dosimeter.

• Journal of Astronomy and Space Sciences
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• 제21권4호
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• pp.467-480
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• 2004

It is very important to eliminate thermal background radiation for the near infrared camera system such as KAONICS (KAO Near Infrared Camera System). Thermal background radiations which come from window and cryostat wall influence IR detector and decrease IR system performance. Therefore the cold box which contains optics and detector housing must be cooled down to eliminate thermal background radiation. We carried out quantitative analysis to determine internal cooling temperature to reduce thermal noise in the J, H, Ks, and L bandpass. Additionally, we estimated the incoming heat load and then chose the cryocooler adequate to KAONICS's requirements. The cooling time and the final cooling temperature of the cold box were calculated. These results were also implemented to the system design.

• Journal of Radiation Protection and Research
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• 제26권1호
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• pp.35-43
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• 2001

All of sealing capsules to transport a special form radioactive material should be designed and fabricated in accordance with the design criteria prescribed in IAEA standards and domestic regulations. The objective of this study is to demonstrate the safety of a shipping capsule for $^{192}Ir$ special form radioisotope which produced in the HANARO. The safety tests were carried out for the impact, percussion, bending and heat test conditions. And leakage tests were carried out before and after the each test. Also, the safety analyses wert performed using computer codes in order to verify the test results. The capsule showed slight scratches and deformation, and maintained its structural and thermal integrities in all tests without any severe damage or melting. It also met the allowable limits of leakage rate after each test. Therefore, it has been verified that the capsule was designed and fabricated to meet all requirements for the special form.

• Journal of Radiation Protection and Research
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• 제10권2호
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• pp.122-129
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• 1985

S-2, W-diaminopentyl isothiuronium bromide and relevant thiophosphate derivative were prepared starting from both phthalimide and l-ornithinic acid. Drug toxicities of the prepared isothiuronium bromide and S-2-(W-aminoalkylamino) ethyl isothiuronium bromides were tested through ICR male mice, 4 and 8 weeks old and weighing $25{\sim}35g$. The former compound was found to be less toxic than those of latter compounds. This difference of drug toxicities seemed to be originated from their chemical structures, which were examined through IR Spectrometry Radioprotective effects of these compounds were discussed through relevant research data and diaminopentyl derivatives are considered to be a potent radioprotectant with low drug toxicity.