• Journal of Advanced Navigation Technology
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• v.27 no.1
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• pp.57-62
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• 2023

This paper proposes a tri-band bandpass filter using dual-mode stepped-impedance resonators (SIRs) with parallel coupled structures. The proposed filter adopts U-shaped SIRs with open stubs and parallel coupled lines (PCLs) that have inter-digital and comb-line shorted ends. Two U-shaped SIRs with open stubs build the first and third passband, and the central PCL resonators build the second passband. Five resonators and coupling structures are theoretically analyzed to derive the scattering parameters of the proposed filter. A novel tri-band bandpass filter is designed and fabricated using the induced scattering parameters. The measured result of the fabricated tri-band bandpass filter shows a good agreement with the simulated one.

• Progress in Medical Physics
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• v.16 no.2
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• pp.62-69
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• 2005

The purpose of this study has been performed to investigate the possibility of external audit program using thermoluminescence dosimetry for electron beam in korea. The TLD system consists of LiF powder, type TLD-700 read with a PCL 3 reader. In order to determine a calibration coefficient of the TLD system, the reference dosimeters are irradiated to 2 Gy in a $^{60}CO$ beam at the KFDA The irradiation is performed under reference conditions is water phantom using the IAEA standard holder for TLD of electron beam. The energy correction factor is determined for LiF powder irradiated of dose to water 2 Gy in electron beams of 6, 9, 12, 16 and 20 MeV (Varian CL 2100C). The dose is determined according to the IAEA TRS-398 and by measurement with a PTW Roos type plane-parallel chamber. The TLD for each electron energy are positioned in water at reference depth. In this study, to verify of the accuracy of dose determination by the TLD system are performed through a 'blind' TLD irradiation. The results of blind test are $2.98\%,\;3.39\%\;and\;0.01\%(1\sigma)$ at 9, 16, 20 MeV, respectively. The value generally agrees within the acceptance level of $5\%$ for electron beam. The results of this study prove the possibility of the TLD quality assurance program for electron beams. It has contributed to the improvement of clinical electron dosimetry in radiotherapy centers.

• The Journal of the Convergence on Culture Technology
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• v.5 no.3
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• pp.271-282
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• 2019

This study was conducted to evaluate physiological activity of Robinia pseudo-acacia leaf and its skin penetration using polymer micelles and skin penetrating peptide. After extraction with Robinia pseudo-acacia using the ethanol and distilled water, various physiological activities were examined. The total concentration of polyphenol compounds was determined to be 47.42 mg/g (ethanol extract), 56.88 mg/g (hydrothermal extract) and DPPH radical scavenging ability at $1,000{\mu}g/mL$ was 44.24% in ethanol extract and it is higher than value(41.50%) in hydrothermal extract. The elastase inhibitory assay showed concentration dependence and elastase inhibition of Robinia pseudo acacia leaf ethanol extract was 54.09%, which was the highest at $500{\mu}g/mL$. In the SOD-like experiments, the concentration-dependent results were showed and the SOD-like activity of the Robinia pseudo-acacia leaf ethanol extract was higher than that of the Robinia pseudo acacia leaf hydrothermal extract at all concentrations. At a concentration of $500{\mu}g/mL$, Robinia pseudo acacia leaf ethanol extract showed the highest SOD-like activity of 76.41%. The tyrosinase inhibition at $20{\mu}g/mL$ was determined to be 56.47% (ethanol extract), 23.05% (hydrothermal extract). In the antimicrobial experiments, the hydrothermal extract had no effect, but ethanol extract represented maximum clear zone of 11.00 mm in Propionbacterium acnes strain and maximum clear zone of 10.50 mm. in Bacillus subtilis strain. To solve the problem of insolubility and to improve skin penetration, PCL-PEG polymer micelles containing Robinia pseudo-acacia leaf ethanol extracts and 1.0% cell permeable peptide, hexa-D-arginine (R6) were successfully prepared with particle size of 108.23 and 126.47 nm and excellent skin permeation effects could be showed.

• Journal of the Korean Chemical Society
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• v.36 no.2
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• pp.255-260
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• 1992

A procedure for spectrophotometric determination of traces of phosphorus(P) in high-purity trichlorosilane(TCS) is proposed using an adsorptive separation. $PCl_3$, which is a dominant P impurity within TCS, is first oxidized by oxygen to a stable form as $POCl_3$. $AlCl_3$ is selected as an adsorbent which forms a thermally stable complex with $POCl_3$ in TCS and can be well dissolved in aqueous ethanol solution. The proposed adsorptive separation method is free from the formation of silica gel and gas bubbles during the colorimetric analysis of TCS. The method reveals that the P concentration in a semiconductor-grade TCS is 5.32 ${\mi}g/l$ within the standard deviation of ${\pm}$ 17%. On the other hand, the P concentration of the purified TCS which is separated from the $AlCl_3$${\cdot}$$POCl_3$ complex is reduced to be less than 0.15 ${\mi}g/l$, showing the efficient applicability of $AlCl_3$ to the wet chemical analysis. The proposed method is also tested to verify the effectiveness of other well-known adsorbents.

• Anxiety and mood
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• v.18 no.2
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• pp.39-47
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• 2022

Objective : This study investigated brain functional connectivity in male firefighters who showed subclinical post-traumatic stress disorder (PTSD) symptoms. Methods : We compared the data of 17 firefighters who were not diagnosed with PTSD and 18 healthy controls who had no trauma exposure. The following instruments were applied to assess psychiatric symptoms: Korean version of the Post-traumatic stress disorder Checklist for DSM-5 (PCL-5-K), Beck Depression Inventory-II (BDI-II), Beck Anxiety Inventory (BAI). For all subjects, functional magnetic resonance imaging was performed, and functional connectivity was compared between the two groups (family-wise error-corrected p<0.05). Additionally, correlations between psychiatric symptoms and functional connectivity were explored. Results : The following connectivity was higher than that of healthy controls: 1) the central opercular cortex-superior temporal gyrus, 2) planum polare-parahippocampal gyrus, 3) angular gyrus-amygdala, and 4) temporal fusiform cortex-parahippocampal gyrus. The functional connectivity of 1) the lateral occipital cortex-inferior temporal gyrus, 2) superior parietal lobule-caudate, and 3) middle temporal gyrus-thalamus were lower in firefighters. In firefighters, the connectivity of the planum polare-parahippocampal gyrus showed a negative correlation with the severity of arousal symptoms (rho=-0.586, p=0.013). The connectivity of the middle temporal gyrus-thalamus showed a positive correlation with the severity of intrusion (rho=0.552, p=0.022) and arousal symptoms (rho=0.619, p=0.008). The connectivity of the temporal fusiform cortex-parahippocampal gyrus was negatively correlated with intrusion (rho=-0.491, p=0.045) and arousal (rho=-0.579, p=0.015). Conclusion : Our results indicate that the brain functional connectivity is associated with occupational trauma exposure in firefighters without PTSD. Therefore, this study provides evidence that close monitoring and early intervention are important for firefighters with traumatic experience even at a subthreshold level.

• Fire Science and Engineering
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• v.33 no.6
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• pp.132-141
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• 2019

This study was conducted to investigate the effects of a forest therapy program on post-traumatic stress disorder (PTSD) and mood states of fire fighters. A total of 293 participants completed two psychological questionnaires before and after the program was conducted: the Post Traumatic Stress Disorder Checklist (PCL) and the Profile of Mood States (POMS). Data were analyzed with paired t-test and ANCOVA using SPSS 24.0. The PTSD results showed a significant decrease from 11.38 ± 12.58 points before the program to 6.91 ± 10.50 points after the program. Results of the POMS questionnaire revealed an increase in positive factors and a decrease in negative factors, with a significant overall decrease in POMS results from 8.58 ± 18.47 points before the program to -0.63 ± 15.83 points after the program. As a result of analyzing the differences in stress reduction effects according to the amount of sleep participants had, PTSD showed improvement at 6-8 hours of sleep. These results are expected to be utilized as a basis for stress management and relief in fire fighters.