• Bulletin of the Korean Space Science Society
• /
• 2004.10b
• /
• pp.356-359
• /
• 2004

Prelaunch thermal analysis of the KSLV (Korea Space Launch Vehicle)-I PLF (Payload Fairing) was performed to predict maximum/minimum liftoff temperatures and to evaluate of air conditioning performance. Prelaunch thermal analysis includes internal air conditioning effect, external convective heating/cooling, radiation exchange with the ground and sky, radiation between spacecraft and PLF, and solar radiation incident on PLF. Analysis was performed at two extreme conditions, hot day condition and cold day condition. The results showed that the maximum liftoff temperature was $53^{\circ}C$ and the minimum liftoff temperature was $-3.8^{\circ}C$. It was also found that conditioned air supplying, in $20{\pm}2^{\circ}C\;and\;1200\;m^3/hr$, is sufficient to keep the internal air in required temperature range.

• Nuclear Medicine and Molecular Imaging
• /
• v.41 no.2
• /
• pp.78-84
• /
• 2007

Quantitative analysis of dynamic brain PET data using a tracer kinetic modeling has played important roles in the investigation of functional and molecular basis of various brain diseases. Parametric imaging of the kinetic parameters (voxel-wise representation of the estimated parameters) has several advantages over the conventional approaches using region of interest (ROI). Therefore, several strategies have been suggested to generate the parametric images with a minimal bias and variability in the parameter estimation. In this paper, we will review the several approaches for parametric imaging with linearized methods which include graphical analysis and mulilinear regression analysis.

• Journal of Environmental Health Sciences
• /
• v.46 no.1
• /
• pp.96-102
• /
• 2020

Objectives: This study identified factors impacting radiation knowledge among aircrew, who are affected by cosmic radiation exposure due to their occupational environment. Methods: In September 2019 we conducted an online survey of aircrew through a Google link. We evaluated the level of radiation knowledge using a ten-item (10 points) questionnaire. The following exploratory variables were evaluated in relationship with the level of radiation knowledge using univariable linear regression models: sex, age, duration of employment, position level, company, marriage, education level, personal/family history of disease, and the number of times acquiring information on radiation through various channels (internet searching, watching television, reading newspaper, conversation about radiation with aircrew/non-aircrew, in-house training). With a p of 0.2 in univariable models, we built a multivariable linear regression model using a stepwise selection method. Results: The average radiation knowledge score of the 356 respondents was 7.22. Univariable linear regression analysis showed that radiation knowledge of the aircrew was associated with their company, position level, age, and number of conversations with other aircrew members. Our multivariable model showed that the radiation knowledge level of aircrew decreased as they had more conversations about radiation with other aircrew members and as their age increased. Conclusions: Korean air crew showed a lower level of radiation knowledge as their age and the number of conversations with colleagues increased. The study suggests that more education is needed in order for aircrew to gain accurate radiation knowledge.

• Journal of the Korean Solar Energy Society
• /
• v.34 no.1
• /
• pp.39-47
• /
• 2014

Solar applications analysis and building energy performance depend on the quality of the solar resource data available. Unfortunately, most of the weather stations do not measure solar radiation data in Korea, as a reason many researchers have studied different solar radiation estimation models and suggested to apply them to various locations in Korea. In addition, they also studied the impact of hourly global solar radiation on energy performance of an office building by comparing the simulated building energy consumptions using four different weather files, one using measured, and three estimated solar radiation from different models, which are Cloud-cover Radiation Model (CRM), Zhang and Huang Model (ZHM), and Meteorological Radiation Model (MRM), and concluded that there was some impact on energy performance of the building due to the using different solar radiation models. However, the result cannot be applied to all other buildings since the simulated office building for that study only used limited building characteristics such as using fixed values of solar heat gain coefficient (SHGC) and window-to-wall ratio (WWR), which are significant parameters related to solar radiation that affect to the building energy consumptions. Therefore, there is a need to identify how the building energy consumption will be changed by varying these building parameters. In this study, the impact of one measured and three estimated global solar radiation on energy performance of the office building was conducted taking account of SHGC and WWR. As a result, it was identified that the impact of four different solar radiation data on energy performance of the office building was evident regardless SHGC and WWR changes, and concluded that the most suitable solar models was changed from the CRM/ZHM to the MRM as SHGC and WWR increases.

• Journal of Radiation Protection and Research
• /
• v.37 no.4
• /
• pp.226-230
• /
• 2012

The gross alpha analysis of nasal smear samples for the radiation emergency and the additional follow-up steps were established. Cotton swab sticks using in local hospitals for nasal smear in Korea were used for the verification. The measurement results of standard samples spiked with certified reference source were well agreed within ${\pm}20%$ compared with reference values. The clearance ratio of smear samples conducted with wet smear condition showed higher value. To eliminate the quenching effect of liquid scintillation samples, dry of smear samples should be followed up before counting samples. Based on the measurement results, medical decision levels and internal dose assessment were established for the victims in the beginning of radiation emergency.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.16 no.3
• /
• pp.1605-1610
• /
• 2015

The present study has been accomplished to elucidate the effect of radiation heat transfer in the heat transfer analysis of refrigerator gasket, which has near 30% of refrigerator heat loss. The numerical heat transfer analysis has been conducted with the simplified modeling of refrigerator gasket. From the present CFD analysis, heat loss at the gasket is $25.6W/m^2$ for the case without radiation effect and that for the case with radiation effect is $55.0W/m^2$, which is 2.2 times greater heat loss. The radiation protection layers were installed in the gasket from 0 to 7 and the case with 7 layers has 33% reduction effect of heat loss compared with the case without any radiation protection layer. Additionally, it is better effect of radiation heat loss reduction that the radiation protection layers would be placed to the outer or inner side of gasket rather than placing to the center of gasket.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.14
• /
• pp.5889-5893
• /
• 2014

Over-expression of epidermal growth factor receptor (EGFR) has been identified as a common feature associated with clinical outcome in many types of cancer, including squamous cell carcinoma of the oesophagus (SCCO). However, the clinical importance of EGFR over-expression in SCCO remains unsettled as conflicting results exist. Therefore we carried out the present meta-analysis of published studies for clarification. A total of 13 studies including 1, 150 patients were enrolled. EGFR over-expression was positive in 722 of these cases. With EGFR over-expression, patients had higher depth of invasion, vascular invasion, and poor prognosis. However, expression had no relation with degree of differentiation, histological grade, lymph node metastasis, clinical stage or lymphatic invasion. EGFR over-expression is probably a valuable predictor for the T stage, vascular invasion and OS, and it could be used as a poor prognosis indicator for the esophageal SCC patients. Targeting therapy to EFGR should be considered to the combined treatment in SCCO.

• Radiation Oncology Journal
• /
• v.37 no.3
• /
• pp.185-192
• /
• 2019

Purpose: The effectiveness of thoracic radiation therapy (TRT) in extensive-stage small cell lung cancer (ES-SCLC) patients is increasingly reported, but there is no definite consensus on its application. The aim of this study was to identify factors associated with better outcomes of TRT among patients with ES-SCLC, focusing on whether a higher TRT dose could improve treatment outcome. Materials and Methods: The medical records of 85 patients with ES-SCLC who received TRT between January 2008 and June 2017 were retrospectively reviewed. Eligibility criteria were a biological effective dose with α/β = 10 (BED) higher than 30 Gy₁₀ and completion of planned radiotherapy. Results: During a median follow-up of 5.3 months, 68 patients (80.0%) experienced disease progression. In univariate analysis, a BED >50 Gy₁₀ was a significant prognostic factor for overall survival (OS; 40.8% vs. 12.5%, p = 0.006), progression-free survival (PFS; 15.9% vs. 9.6%, p = 0.004), and intrathoracic PFS (IT-PFS; 39.3% vs. 20.5%, p = 0.004) at 1 year. In multivariate analysis, a BED >50 Gy₁₀ remained a significant prognostic factor for OS (hazard ratio [HR] = 0.502; 95% confidence interval [CI], 0.287-0.876; p = 0.015), PFS (HR = 0.453; 95% CI, 0.265-0.773; p = 0.004), and IT-PFS (HR = 0.331; 95% CI, 0.171-0.641; p = 0.001). Response to the last chemotherapy was also associated with better OS in both univariate and multivariate analysis. Conclusion: A TRT dose of BED >50 Gy₁₀ may be beneficial for patients with ES-SCLC. Further studies are needed to select patients who will most benefit from high-dose TRT.

• Journal of radiological science and technology
• /
• v.39 no.2
• /
• pp.209-225
• /
• 2016

In this study, radiation workers who work in nuclear medicine department were analyzed to find the cause of differences of radiation exposure from General Characteristic, Knowledge, Recognition and Conduct, especially females working on nuclear medicine radiation, in order to pave the way for positive defense against radiation exposure. The subjects were 106 radiation workers who were divided into two groups of sixty-four males and forty-two females answered questions about their General Characteristic, Knowledge, Recognition, Conduct, and radiation exposure dose which was measured by TLD (Thermo Luminescence Dosimeter). The results of the analysis revealed that as the higher score of knowledge and conduct was shown, the radiation exposure decreased in female groups, and as the higher score of conduct was shown, the radiation exposure decreased in male groups. In the correlation analysis of female groups, the non-experienced in pregnancy showed decreasing amount of radiation exposure as the score of knowledge and conduct was higher and the experienced in pregnancy showed decreasing amount of radiation exposure as the score of recognition and conduct was higher. In the regression analysis on related factors of radiation exposure dose of nuclear medicine radiation workers, the gender caused the meaningful result and the amount of radiation exposure of female groups compared to male groups. In the regression analysis on related factors of radiation exposure dose of female groups, the factor of conduct showed a meaningful result and the amount of radiation exposure of the experienced in pregnancy was lower compared to the non-experienced. The conclusion of this study revealed that radiation exposure of female groups was lower than that of male groups. Therefore, male groups need to more actively defend themselves against radiation exposure. Among the female groups, the experienced in pregnancy who have an active defense tendency showed a lower radiation exposure. Thus, those who have never been pregnant need to have a more active defensive conduct for the future possibility of pregnancy.

• Journal of the Korean Institute of Telematics and Electronics A
• /
• v.33A no.11
• /
• pp.44-51
• /
• 1996

The radiation characteristics of a slot antenna in a plane conductor covered with a miving isotropic plasma layer are analyzed. The radiation null which causes distortion in radiation pattern is explainted by the zero of integrand in an asymptotic integral for radiation fields as a function of the plasma parameter and the plasma velocity. Numerical resutls for a radiation null calculated from various plasma and velocity parameters correspond to the results of two-dimensional problem.