• Clean Technology
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• v.19 no.3
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• pp.264-271
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• 2013

In this study, we optimized the removal condition of contaminants attached on the scrap surface to recycle the scrap generated from the Zr alloy tube manufacturing process back to the nuclear grade. The main contaminant is remnant of watersoluble cooling lubricant that is used in the pilgering manufacture during the tube production, and it is assumed to be compressed and carbonized on the surface of tube. Zirlo alloy tube of ${\phi}9.50mm$, which has high occurrence frequency of scrap, was selected as the object to be cleaned, and cleaning abilities of reagents were evaluated by measuring the characteristics of contaminants remained and by analyzing the surface of the tube after cleaning process. For evaluation of each cleaning agent, we selected two types of sodium hydroxide series and three types of potassium hydroxide series. Furthermore, to confirm dependence on tempe-rature and ultrasonic intensities, cleaning at the room temperature, $40^{\circ}C$, and $60^{\circ}C$ was conducted, and results showed that higher the cleaning temperature and higher the ultrasonic intensity, better the cleaning effect. As a result of the bare-eye inspection, while the use of sodium hydroxide provided satisfactory condition on the tube surface, the use of potassium hydroxide series provided satisfactory condition on the tube surface only when the ultrasonic intensity was over 120 W. In the cleaning effect analysis using the gravimetric method, cleaning efficiency of sodium hydroxide series was as high as 97.6% ($60^{\circ}C$, 120 W), but since the tube surface condition was poor after the use of potassium hydroxide, the gravimetric method was not appropriate. In the analytical result of surface contaminants on the tube surface, C, O, Ca, and Zr were detected, and mainly C and O dominated the proportion of contaminants. It was also found that the degree of cleaning on the tube affected the componential ratio of C and O; if the degree of cleaning is high, or if cleaning is well-conducted, the proportion of C is decreased, and the proportion of O is increased. Based on these results, optimal cleaning for application in the industry can be expected by categorizing cleaning process into three steps of Alkali cleaning, Rinsing, and Drying and by adjusting cleaning parameters in each step.

• The Korean Journal of Nuclear Medicine
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• v.36 no.1
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• pp.1-7
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• 2002

Positron Emission Tomography (PET) is a nuclear medicine imaging modality that consists of systemic administration to a subject of a radiopharmaceutical labeled with a positron-emitting radionuclide. Following administration, its distribution in the organ or structure under study can be assessed as a function of time and space by (1) defecting the annihilation radiation resulting from the interaction of the positrons with matter, and (2) reconstructing the distribution of the radioactivity from a series of that used in computed tomography (CT). The nuclides most generally exhibit chemical properties that render them particularly desirable in physiological studies. The radionuclides most widely used in PET are F-18, C-11, O-15 and N-13. Regarding to the number of the current PET Centers worldwide (based on ICP data), more than 300 PET Centers were in operation in 2000. The use of PET technology grew rapidly compared to that in 1992 and 1996, particularly in the USA, which demonstrates a three-fold rise in PET installations. In 2001, 194 PET Centers were operating in the USA. In 1994, two clinical and research-oriented PET Centers at Seoul National University Hospital and Samsung Medical Center, was established as the first dedicated PET and Cyclotron machines in Korea, followed by two more PET facilities at the Korea Cancer Center Hospital, Ajou Medical Center, Yonsei University Medical Center, National Cancer Center and established their PET Center. Catholic Medical School and Pusan National University Hospital have finalized a plan to install PET machine in 2002, which results in total of nine PET Centers in Korea. Considering annual trends of PET application in four major PET centers in Korea in Asan Medical Center recent six years (from 1995 to 2000), a total of 11,564 patients have been studied every year and the number of PET studies has shown steep growth year upon year. We had 1,020 PET patients in 1995. This number increased to 1,196, 1,756, 2,379, 3,015 and 4,414 in 1996,1997,1998,1999 and 2000, respectively. The application in cardiac disorders is minimal, and among various neuropsychiatric diseases, patients with epilepsy or dementia can benefit from PET studios. Recently, we investigated brain mapping and neuroreceptor works. PET is not a key application for evaluation of the cardiac patients in Korea because of the relatively low incidence of cardiac disease and less costly procedures such as SPECT can now be performed. The changes in the application of PET studios indicate that, initially, brain PET occupied almost 60% in 1995, followed by a gradual decrease in brain application. However, overall PET use in the diagnosis and management of patients with cancer was up to 63% in 2000. The current medicare coverage policy in the USA is very important because reimbursement policy is critical for the promotion of PET. In May 1995, the Health Care Financing Administration (HCFA) began covering the PET perfusion study using Rubidium-82, evaluation of a solitary pulmonary nodule and pathologically proven non-small cell lung cancer. As of July 1999, Medicare's coverage policy expanded to include additional indications: evaluation of recurrent colorectal cancer with a rising CEA level, staging of lymphoma and detection of recurrent or metastatic melanoma. In December of 2001, National Coverage decided to expand Medicare reimbursement for broad use in 6 cancers: lung, colorecctal, lymphoma, melanoma, head and neck, and esophageal cancers; for determining revascularization in heart diseases; and for identifying epilepsy patients. In addition, PET coverage is expected to further expand to diseases affecting women, such as breast, ovarian, uterine and vaginal cancers as well as diseases like prostate cancer and Alzheimer's disease.

• Korean Security Journal
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• no.26
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• pp.29-58
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• 2011

Since 11 September 2001, warnings of risk in the nexus of terrorism and nuclear weapons and materials which poses one of the gravest threats to the international community have continued. The purpose of this study is to analyze the aim, principles, characteristics, activities, impediments to progress and developmental recommendation of the Global Initiative to Combat Nuclear Terrorism(GICNT). In addition, it suggests implications of the GICNT for the ROK policy. International community will need a comprehensive strategy with four key elements to accomplish the GICNT: (1) securing and reducing nuclear stockpiles around the world, (2) countering terrorist nuclear plots, (3) preventing and deterring state transfers of nuclear weapons or materials to terrorists, (4) interdicting nuclear smuggling. Moreover, other steps should be taken to build the needed sense of urgency, including: (1) analysis and assessment through joint threat briefing for real nuclear threat possibility, (2) nuclear terrorism exercises, (3) fast-paced nuclear security reviews, (4) realistic testing of nuclear security performance to defeat insider or outsider threats, (5) preparing shared database of threats and incidents. As for the ROK, main concerns are transfer of North Korea's nuclear weapons, materials and technology to international terror groups and attacks on nuclear facilities and uses of nuclear devices. As the 5th nuclear country, the ROK has strengthened systems of physical protection and nuclear counterterrorism based on the international conventions. In order to comprehensive and effective prevention of nuclear terrorism, the ROK has to strengthen nuclear detection instruments and mobile radiation monitoring system in airports, ports, road networks, and national critical infrastructures. Furthermore, it has to draw up effective crisis management manual and prepare nuclear counterterrorism exercises and operational postures. The fundamental key to the prevention, detection and response to nuclear terrorism which leads to catastrophic impacts is to establish not only domestic law, institution and systems, but also strengthen international cooperation.

• Journal of the Korean Society of Radiology
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• v.10 no.7
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• pp.477-482
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• 2016

This study is tried to determine whether the management of medical radiation is well handled by comparison the guidelines of KFDA(korea food & drug administration) with analysis of dose indicator in mammography. As a method, it is analysed that kVp, exposure time, mAs, compressed breast thickness, average glandular dose and body mass index that were classified in the examination of both breasts by CC(cranio-caudal) and MLO(medio-lateral oblique) with EMR(electronic medical record) and dose report that were sent to the PACS(picture archiving communication system). As a result, in the site inspection according to the age, Compressed breast thickness in CC and MLO were the thickest of 45.6 mm and 49.6 mm in the 50-59 year old respectively. In the overall average compressed breast thickness, CC were 44.2 mm and MLO were 48.9 mm. MLO has more thick by 4.7 mm. In average glandular dose, CC were 1.05 mGy and MLO were 1.14 mGy. MLO has higher by 0.09 mGy than CC. As the compressed breast thickness increases 10mm, CC and MLO increases 0.15 mGy and 0.17 mGy respectively. When it was compared with the average glandular dose of 1.16 mGy per 1 film presented by KFDA, CC was showed 1.05 mGy. However, the 60 mm or more was found to exceed a 1.30 mGy. Also, As the compressed breast thickness was higher, body mass index showed high score. And in the case of 25 or more in the obese body index according to body mass index, it was showed obesity in case of the compressed breast thickness was more than 50mm.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.307-319
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• 2016

A Land-Atmosphere Modeling Package (LAMP) for supporting agricultural and forest management was developed at the National Center for AgroMeteorology (NCAM). The package is comprised of two components; one is the Weather Research and Forecasting modeling system (WRF) coupled with Noah-Multiparameterization options (Noah-MP) Land Surface Model (LSM) and the other is an offline one-dimensional LSM. The objective of this paper is to briefly describe the two components of the NCAM-LAMP and to evaluate their initial performance. The coupled WRF/Noah-MP system is configured with a parent domain over East Asia and three nested domains with a finest horizontal grid size of 810 m. The innermost domain covers two Gwangneung deciduous and coniferous KoFlux sites (GDK and GCK). The model is integrated for about 8 days with the initial and boundary conditions taken from the National Centers for Environmental Prediction (NCEP) Final Analysis (FNL) data. The verification variables are 2-m air temperature, 10-m wind, 2-m humidity, and surface precipitation for the WRF/Noah-MP coupled system. Skill scores are calculated for each domain and two dynamic vegetation options using the difference between the observed data from the Korea Meteorological Administration (KMA) and the simulated data from the WRF/Noah-MP coupled system. The accuracy of precipitation simulation is examined using a contingency table that is made up of the Probability of Detection (POD) and the Equitable Threat Score (ETS). The standalone LSM simulation is conducted for one year with the original settings and is compared with the KoFlux site observation for net radiation, sensible heat flux, latent heat flux, and soil moisture variables. According to results, the innermost domain (810 m resolution) among all domains showed the minimum root mean square error for 2-m air temperature, 10-m wind, and 2-m humidity. Turning on the dynamic vegetation had a tendency of reducing 10-m wind simulation errors in all domains. The first nested domain (7,290 m resolution) showed the highest precipitation score, but showed little advantage compared with using the dynamic vegetation. On the other hand, the offline one-dimensional Noah-MP LSM simulation captured the site observed pattern and magnitude of radiative fluxes and soil moisture, and it left room for further improvement through supplementing the model input of leaf area index and finding a proper combination of model physics.

• Korean Journal of Agricultural and Forest Meteorology
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• v.2 no.4
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• pp.183-189
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• 2000

This study was carried out to analyze ecophysiological responses for seedling of Quercus serrata, Quercus mongolica and Quercus variabilis that are the typical species of deciduous broadleaved forests in Korea. And executed experiments in the climatic control room to provide necessary information to ecological forest management and methods of natural regeneration through the analysis of seedling responses. The details of experimental analysis were growth processes of 4 months after seeding that vary with the condition of three light intensity[relative light intensity(RLI) 8%, 20%, 52%] and three soil moisture[water suction(WS) Ψ=100 hPa, Ψ=280 hPa, Ψ=330 hPa] gradient, growth factors after harvesting and the nutrition condition of leaves. The results of this study are followings: 1) Early growth was prosperous after germination for the species which have more weight of acorn. 2) The formation of lammas shoot was favourable with Q. variabilis and Q. mongolica. And the rate of the occurrence was the highest in the RLI 20%, and it was remarkably reduced in the RLI 8%. 3) As the height growth of seedling of all 3 species were greater in the RLI 20% and 8% than that of the RLI 52%, they showed strong shade tolerance. 4) The increase of light intensity promoted the diameter at root collar growth, and development of main and lateral roots with all 3 species. 5) It showed that the increase of light intensity in the experimental radiation condition raised special leaf area weight(mg/cm$^2$) and leaf area productivity(mg/cm$^2$). Consequently, these resulted in the increase of leaf thickness and total dry biomass per the unit area of leaf. 6) As the increase of light intensity, the minerals contents of leaves such as N, P and K were lowered, and the increase of soil moisture resulted in the increase of P, K, Ca and Mg.

• Korean Journal of Agricultural and Forest Meteorology
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• v.23 no.4
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• pp.198-221
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• 2021

After large-scale reforestation in the 1960s and 1970s, forests in Korea have gradually been aging. Net ecosystem CO₂ exchange of old-growth forests is theoretically near zero; however, it can be a CO₂ sink or source depending on the intervention of disturbance or management. In this study, we report the CO₂ budget dynamics of the Gwangneung deciduous old-growth forest (GDK) in Korea and examined the following two questions: (1) is the preserved GDK indeed CO₂ neutral as theoretically known? and (2) can we explain the dynamics of CO₂ budget by the common mechanisms reported in the literature? To answer, we analyzed the 15-year long CO₂ flux data measured by eddy covariance technique along with other biometeorological data at the KoFlux GDK site from 2006 to 2020. The results showed that (1) GDK switched back-and-forth between sink and source of CO₂ but averaged to be a week CO₂ source (and turning to a moderate CO₂ source for the recent five years) and (2) the interannual variability of solar radiation, growing season length, and leaf area index showed a positive correlation with that of gross primary production (GPP) (R²=0.32~0.45); whereas the interannual variability of both air and surface temperature was not significantly correlated with that of ecosystem respiration (RE). Furthermore, the machine learning-based model trained using the dataset of early monitoring period (first 10 years) failed to reproduce the observed interannual variations of GPP and RE for the recent five years. Biomass data analysis suggests that carbon emissions from coarse woody debris may have contributed partly to the conversion to a moderate CO₂ source. To properly understand and interpret the long-term CO₂ budget dynamics of GDK, new framework of analysis and modeling based on complex systems science is needed. Also, it is important to maintain the flux monitoring and data quality along with the monitoring of coarse woody debris and disturbances.

• Journal of Bio-Environment Control
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• v.32 no.1
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• pp.48-56
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• 2023

High-pressure sodium (HPS) lamps have been widely used as a useful supplemental light source to emit sufficient photosynthetically active radiation and provide a radiant heat, which contribute the heat requirement in greenhouses. The objective of this study to analyze the thermal characteristics of HPS lamp and thermal behavior in supplemented greenhouse, and evaluate the performance of a horizontal leaf temperature of sweet pepper plants using computational fluid dynamics (CFD) simulation. We simulated horizontal leaf temperature on upper canopy according to three growth stage scenarios, which represented 1.0, 1.6, and 2.2 plant height, respectively. We also measured vertical leaf and air temperature accompanied by heat generation of HPS lamps. There was large leaf to air temperature differential due to non-uniformity in temperature. In our numerical calculation, thermal energy of HPS lamps contributed of 50.1% the total heat requirement on Dec. 2022. The CFD model was validated by comparing measured and simulated data at the same operating condition. Mean absolute error and root mean square error were below 0.5, which means the CFD simulation values were highly accurate. Our result about vertical leaf and air temperature can be used in decision making for efficient thermal energy management and crop growth.

• Journal of Korean Dental Hygiene Science
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• v.6 no.2
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• pp.115-127
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• 2023

Background: This study was conducted to determine the level of job satisfaction and patient safety cultural activities for dental hygienists and to determine the relationship between job satisfaction and patient safety cultural activities. Methods: A survey was conducted on 214 dental hygienists, and data from the final 180 were analyzed. Job satisfaction consisted of a total of 20 questions, and patient safety cultural activities included a total of 25 questions. The survey was conducted on a 5-point scale. Results: The average job satisfaction score of the study subjects was 3.44 points. Among patient safety cultural activities, infection control had the highest average score (4.12 points) and radiation safety management had the lowest average score (3.10 points). Patients with less than 3 years of clinical experience (4.01 points) had higher patient safety culture activity scores than those with 3 to 10 years of clinical experience (3.72 points) and those with more than 10 years of clinical experience (3.69 points). The level of patient safety cultural activities was statistically significantly higher as age, less clinical experience, and job satisfaction increased (p<0.05). Conclusion: In the case of dental hygienists, patient safety cultural activities must be carried out throughout the entire work, so an active will to practice patient safety cultural activities is necessary. In order to improve the performance of patient safety cultural activities, it is necessary to adjust the workload of dental hygienists to improve job satisfaction and create a work environment in which they can focus on patient safety cultural activities.

• Korean Journal of Head & Neck Oncology
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• v.6 no.2
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• pp.79-84
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• 1990

This paper is a review of our experience with radical resection for cancer of the oral cavity with particular emphasis upon the value of myocutaneous(i.e., musculocutanous) flaps employed in the surgical reconstruction in patient survival. During the past 15 years, 98 patients underwent resection of cancer arising in the oral cavity and oropharynx. Of these, 14 had composite resections in which the mandible was not sectioned, and 4 underwent en bloc resections without neck dissections in the face of post-radiation recurrence. When these excluded, 84 patients who underwent COMMANDO procedures with or without myocutaneous flaps were suitable for analysis of recurrence and survival according to the various surgical technics employed. 1) According to the surgical technic, there were 24 standard COMMANDO procedures in whom no regional or myocutanous flap was used; 12 patients who underwent reconstruction employing a forehead flap; 19 patients in whom a posterior cervical 'nape' flap was employed; 27 patients who underwent myocutaneous or osteo-myocutaneous flap repair; and two patients who had double flap repair. 2) The uncorrected two-year disease free survival was 41% for standard COMMANDOs, 17% for forehead flap COMMANDOs; 35% for nape flap COMMANDOs; and 35% for myocutaneous flap COMMANDO procedures. 3) The two-year disease-free survival by Stage was 100% in Stage I, 45% in Stage II, 41% in Stage III, and 18% in Stage IV. 4) When myocutanous flaps cases were compared with Group I, comprised of matched historical controls including both Standard COMMANDOs and those who had undergone regional flap repairs(that is, forehead and nape flap COMMANDOs)there was no difference, both groups showing a 40% 2-year disease-free survival. 5) When musculocutanous flap cases were compared with Goup II, which was composed of matched historical controis limited to patients who had undergone regional flap repairs(that is, forehead and nape flap cases only)there was no difference, both groups showing a 27% 2-year desease-free survival. 6) When musculocutanous flap cases were compared with Group III, composed of patients who had undergone classic COMMANDO procedures without any sort of flap repair, there was a striking difference; the patients undergoing MC flap repair showed 50% 2-year disease-free survival, whereas the classic COMMANDO cases showed a 25% survival free of disease. 7) Locoregional recurrence was also evaluated in the four categories; for standard COMMANDO cases it was 25%, for nape flap cases 26% ; for forehead flap cases, 33%, and for the musculocutaneous flap cases, the lowest recurrence rate, 22%. These results are of particular significance in view of the fact that the proportion of advanced cases(Stage III and IV)in each category was 67% of standard cases, 79% of nape flap patients, 100% of forehead flap cases, and 96% of musculocutaneous flap cases.