• Journal of Radiation Industry
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• v.9 no.4
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• pp.217-221
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• 2015

When reactor coolant leaks occur due to cracks of a steam generator's tube, radioactive materials contained in the primary cooling water in nuclear power plant are forced out toward the secondary systems. At this time the secondary water purification resin in the ion exchange resin tower of the steam generator blowdown system is contaminated by the radioactivity of the leaked radioactive materials, so we pack this in special containers and store temporarily because we could not dispose it by ourselves. If steam generator tube leakage occurs, it produces contaminated spent resins annually about 5,000~7,000 liters. This may increase the amount of nuclear waste productions, a disposal working cost and a unit price of generating electricity in the plant. For this reasons, it is required to develop a decontamination process technique for reducing the radioactive level of these resins enough to handle by the self-disposal method. In this research, First, Investigated the structure and properties of the ion exchange resin used in a steam generator blowdown system. Second, Checked for a occurrence status of contaminated spent resin and a disposal technology. Third, identified the chemical characteristics of the waste radionuclides of the spent resin, and examined ionic bonding and separation mechanism of radioactive nuclear species and a spent resin. Finally, we carried out the decontamination experiment using chemicals, ultrasound, microbubbles, supercritical carbon dioxide to process these spent resin. In the case of the spent resin decontamination method using chemicals, the higher the concentration of the drug decontamination efficiency was higher. In the ultrasound method, foreign matter of the spent resin was removed and was found that the level of radioactivity is below of the MDA. In the microbubbles method, we found that the concentration of the radioactivity decreased after the experiment, so it can be used to the decontamination process of the spent resin. In supercritical carbon dioxide method, we found that it also had a high decontamination efficiency. According to the results of these experiments, almost all decontamination method had a high efficiency, but considering the amounts of the secondary waste productions and work environment of the nuclear power plant, we judged the ultrasound and supercritical carbon dioxide method are suitable for application to the plant and we established the plant applicable decontamination process system on the basis of these two methods.

• Journal of the Korean Society of School Health
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• v.24 no.2
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• pp.141-154
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• 2011

Purpose: The purpose is to provide basic information for establishing improvements on performance-based pay's evaluation method of health teachers. Methods: For subjects, 200 teachers at public elementary schools and 200 health teachers at public elementary schools in Gyeonggi-do were conveniently sampled, and then surveyed through a questionnaire. The questionnaire was to recognize recognition of teachers working under the teacher's performance-based pay system, which was quoted in the questionnaire of Choi ji-hye (2005) and Lee mi-gyeong (2008). Inquiry for the recognition of teachers on evaluation of health teacher's performance-based pay system and improvements on the performance-based pay's evaluation method of health teachers were used after consultation with five incumbent health teachers and a review with the thesis director. Results: The performance-based pay's evaluation method of health teachers has the same method with general teachers in schools, so it is not fair to evaluate the performance of health teachers. The ways to improve the performance-based pay evaluation method of health teachers is as follows: first, the approval on improving 'the number of class hours' which is a detailed item of a teacher's performance evaluation criterion to 'the number of health lesson hours per week and the number of students visiting the school infirmary per week'; second, improving 'life guidance' into 'counseling results of medically-treated students, parents of students and personal hygiene guidance'; third, improving 'a teacher in charge' into 'awarding of points by being recognized as a health teacher in charge of all students and considering the economic situation of the region,; forth, improving 'difficulty of position' into 'the number of health-teacher's annual promotion task items and the treatment number of issuing and receiving of official documents', and improving the 'task difficulty' into 'importance and urgency of emergency patient management, risk level and urgency of infectious diseases and avoiding work in charge' appeared to be more than 90% respectively. Conclusion: The performance-based pay system of teachers being carried out every year should be executed by preparing fair evaluation criteria suitable for task properties and the role of health teachers with different evaluation criteria compared to general teachers.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.8
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• pp.649-656
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• 2019

Flux cored arc welding (FCAW), which is used widely in many fields, such as shipyards, bridge structures, construction machinery, and plant industry, is an alternative to shielded metal arc welding (SMAW). FCAW is used largely in the welding of carbon and alloy steel because it can be welded in all poses and obtain excellent quality in the field under a range of working conditions. In this study, the mechanical properties of welded parts were analyzed after different welding of SS400 and SM490A using FCAW. The following conclusions were drawn. The tensile test results satisfied the KS standard tensile strength in the range of 400~510 N/mm2 in all welding positions. The bending test confirmed that most of the specimens did not show surface breakage or other defects during bending and exhibited sufficient toughness, even after plastic deformation. The hardness test results were lower than the standard value of 350 Hv of KS B 0893. Similar to the hardness test, were greater than the KS reference value. The macro test revealed no internal flaws, non-metallic inclusions, bubbles or impurities on the entire cross section of the weld, and there were no concerns regarding lamination.

• Korean Journal of Heritage: History & Science
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• v.48 no.1
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• pp.148-165
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• 2015

Iron was one of the most influential factors for formation and development of ancient countries. The diffusion of ironware had increased agricultural productivity and brought about military technical revolution. Needless to say, the rise and fall of the countries depended on the possession of stable iron production. Raw materials and fuels are the key factors for mass production of iron and a transportation route is essential to supply the goods. Jungwon area satisfies the three factors. There are many iron manufacture sites such as Jincheon Seokjang-ri Gusan-ri, and Chunju Chilgeum-dong Tangeumdae earthen ramparts in the Jungwon area. In order to study the ancient iron manufacture technique, reconstitution experiment was carried out using restored furnace which was made based on the Jincheon Seokjang-ri B-23 furnace. Some notable results were identified with the experiment as in the followings. Firstly, a roasting process has a connection with the decrease of hardness of the iron ore. Secondly, melting of the blast pipe as well as the formation of product within the furnace had a crucial effect on the cessation of the experiment. Thirdly, reduced iron in various locations within the furnace prove that there was enough reducing environment during the working. Not only melting point but also properties of iron can vary depending on the carbon contents. For the reason, formation of approximate environment in which iron can react to the chalcoal is the most important factor in terms of iron manufacture.

• Journal of Drive and Control
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• v.17 no.4
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• pp.133-140
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• 2020

Traction performance of a tractor varies depending on soil conditions. Sinkage and slip of the driving wheel for tractor frequently occur in a reclaimed land. The objective of this study was to develop a tractor suitable for a reclaimed land. Traction performance was evaluated according to soil conditions of reclaimed land and paddy field. Field experiments were conducted at two test sites (Fields A: paddy field; and Field B: reclaimed land). The tractor load measurement system was composed of an axle rotation speed sensor, a torque meter, a six-component load cell, GPS, and a DAQ (Data Acquisition System). Soil properties including soil texture, water content, cone index, and electrical conductivity (EC) were measured. Referring to previous researches, the tractor traveling speed was set to B3 (7.05 km/h), which was frequently used in ridge plow tillage. Soil moisture contents were 33.2% and 48.6% in fields A and B, respectively. Cone index was 2.1 times higher in field A than in field B. When working in the reclaimed land, slip ratios were about 10.5% and 33.1% for fields A and B, respectively. The engine load was used almost 100% of all tractors under the two field conditions. Traction powers were 31.9 kW and 24.2 kW for fields A and B, respectively. Tractive efficiencies were 83.3% and 54.4% for fields A and B, respectively. As soil moisture increased by 16.4%, the tractive efficiency was lowered by about 28.9%. Traction performance of tractor was significantly different according to soil conditions of fields A and B. Therefore, it is necessary to improve the traction performance of tractor for smooth operations in all soil conditions including a reclaimed land by reflecting data of this study.

• The Korean Journal of Archival Studies
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• no.71
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• pp.237-272
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• 2022

In 2019, the pilot project to establish a record management system for administrative information datasets started in earnest under the leadership of the National Archives. Based on the results of the three-year project by 2021, the improved administrative information dataset management plan will be reflected in public records-related laws and guidelines. Through this, the administrative information dataset becomes the target of full-scale public record management. Although public records have been converted to electronic documents and even the datasets of administrative information systems have been included in full-scale public records management, research on the quality requirements of data itself as raw data constituting records is still lacking. If data quality is not guaranteed, all four properties of records will be threatened in the dataset, which is a structure of data and an aggregate of records. Moreover, if the reliability of the quality of the data of the administrative information system built by reflecting the various needs of the working departments of the institution without considering the standards of the standard records management system is insufficient, the reliability of the public records itself can not be secured. This study is based on the administrative information dataset management plan presented in the "Administrative Information Dataset Recorded Information Service and Utilization Model Study" conducted by the National Archives of Korea in 2021. A study was conducted. By referring to various data, especially public data-related policies and guides, which are being promoted across the government, we would like to derive quality evaluation requirements in terms of records management and present specific indicators. Through this, it is expected that it will be helpful for record management of administrative information dataset which will be in full swing in the future.

• Analyses & Alternatives
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• v.7 no.2
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• pp.35-77
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• 2023

This study aims to solve the entangled loop between demographic transition (DT) and economic growth by analyzing cross-country data. We undertake a national-level group analysis to verify the compressed transition of demographic variables over time. Assuming that the LA (latecomer advantage) on DT over time exists, we verify that the DT of the latecomer is compressed by providing a formal proof of LA on DT over income. As a DT has the double-kinked functions of income, we check them in multiple aspects: early maturation, leftward threshold, and steeper descent under a contour map and econometric methods. We find that the developing countries (the latecomer) have speedy DT (CDT, compressed DT) as well as speedy income such that DT of the latecomers starts at lower levels of income, lasts for a shorter period, and finishes at the earlier stage of economic development compared to that of developed countries (the early mover). To check the balance of DT, we classify countries into four groups of DT---balanced, slow, unilateral, and rapid transition countries. We identify that the main causes of rapid transition are due to the strong family planning programs of the government. Finally, we check the effect of latecomer's CDT on economic growth inversely: we undertake the simulation of the CDT effect on economic growth and the aging process for the latecomer. A worrying result is that the CDT of the latecomer shows a sharp upturn of the working-age population, followed by a sharp downturn in a short period. Compared to early-mover countries, the latecomer countries cannot buy more time to accommodate the workable population for the period of demographic bonus and prepare their aging societies for demographic onus. Thus, we conclude that CDT is not necessarily advantageous to developing countries. These outcomes of the latecomer's CDT can be re-interpreted as follows. Developing countries need power sources to pump up economic development, such as the following production factors: labor, physical and financial capital, and economic systems. As for labor, the properties of early maturation and leftward thresholds on DTs of the latecomer mean that demographic movement occurs at an unusually early stage of economic development; this is similar to a plane that leaks fuel before or just before take-off, with the result that it no longer flies higher or farther. What is worse, the property of steeper descent represents the falling speed of a plane so that it cannot be sustained at higher levels, and then plummets to all-time lows.

• Herbal Formula Science
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• v.11 no.2
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• pp.1-18
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• 2003

The Theory for Monarch, Minister, Adjuvant and Dispatcher (or the Theory of Principal, Assistant, Adjuvant and Guiding Korean Oriental Herbal Medicines) has served as a standard principle for newly developed prescription formulas as well as established ones. Despite its significance, however, this theory hasn't been thoroughly studied and covered in the academic journals of Korean Oriental Herbal Medicines (KOHM) yet. This paper inquires into the origin of the theory while presenting the definitions and functions of Principal, Assistant, Adjuvant, and Guiding KOHM. In the end, the recommended doses and number of the KOHM comprising each of Principal, Assistant, Adjuvant, and Guiding KOHM are suggested. The compatibility theory of Principal, Assistant, Adjuvant, and Guiding KOHM can be traced back to the Warring States Period during which it was recorded in the treatise of the various schools of thoughts and their exponents. The theory was firmly established as a full system in ${\ulcorner}Shinnong's\;Pharmacopoeia{\lrcorner}\;and\;{\ulcorner}Yellow\;Emperor's\;Cannon\;of\;Internal\;Medicine{\lrcorner}$. While ${\ulcorner}Shinnong's\;Pharmacopoeia{\lrcorner}$ focuses on the classification of the properties of KOHM, ${\ulcorner}Yellow\;Emperor's\;Cannon\;of\;Internal\;Medicine{\lrcorner}$ mainly deals with the principles for writing prescriptions. In this regard, it is ${\ulcorner}Yellow\;Emperor's\;Cannon\;of\;Internal\;Medicine{\lrcorner}$ that systemized the Theory of Principal, Assistant, Adjuvant, and Guiding KOHM in a real sense. Principal KOHM aims at the causes of diseases and treat main symptoms. The doses are greater than Assistant, Adjuvant and Guiding KOHM. With their comprehensive effects, Principal KOHM is a leading ingredient of any prescription formula. Assistant KOHM are similar to Principal KOHM in its natures and flavors. Although its natures, flavors as well as efficacies may slightly differ from those of Principal KOHM, Assistant KOHM strengthens the therapeutic effects, jointly working with Principal KOHM. They mainly treat accompanying diseases and symptoms. Adjuvant KOHM is divided into two types: facilitator and inhibitor. Facilitators with the similar properties to those of Principal and Assistant KOHM help strengthen the therapeutic effects. Since they usually treat accompanying symptoms or secondary accompanying symptoms (minor accompanying symptoms), there are two kinds of facilitators. (1) The first kind of facilitators assists Principal KOHM, targeting accompanying symptoms. (2) The second ones supporting Assistant KOHM are for accompanying or secondary accompanying symptoms (or minor accompanying symptoms). Inhibitors counteract and thereby complement Principal and Assistant KOHM. Some of them inhibit the side effects or toxicity of Principal KOHM for the sake of the safety of the whole prescription formula while the others generate induced interactions. Guiding KOHM can be used for two purposes: guiding and mediating. The Guiding KOHM for the former purpose leads the other KOHM in a prescription formula to the lesion. But, the Guiding KOHM for mediating coodinate and harmonize all the ingredients in a prescription formula. The number of KOHM for those Principal, Assistant, Adjuvant and Guiding KOHM and their doses are different, depending on the types of prescriptions: classical prescriptions, prescriptions after ${\ulcorner}$Treatise of Cold-Induced Diseases${\lrcorner}$ and prescriptions of Sasang Constitutions Medicines. In the case of the prescriptions after ${\ulcorner}$Treatise of Cold-Induced Diseases${\lrcorner}$, it is highly recommended to follow the view of ${\ulcorner}$Thesaurus of Korean Oriental Medicine Doctors in Chosun Dynasty${\lrcorner}$ for the number of KOHM to be used. For the doses, however, ${\ulcorner}$Elementary Course for Medicine${\lrcorner}$, is found to be more accurate. The most appropriate number of KOHM per prescription is 11-13. To be more specific, for one prescription formula, it is recommended to administer one kind of KOHM for Principal KOHM, 2-3 for Assistant KOHM, 3-4 for Adjuvant KOHM and 5 for Guiding KOHM. As for the proportion of the doses, when 10 units are to be administered for Principal KOHM in a formula, the doses for the other three should be 7-8 units for Assistant KOHM, 5-6 for Adjuvant KOHM and 3-4 for Guiding KOHM. The doses of the KOHM added to or taken out of the prescription correspond to those of Adjuvant and Guiding KOHM.

• Korean Journal of Agricultural Science
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• v.22 no.1
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• pp.1-10
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• 1995

All agricultural crops and products should be cultured, harvested, handled and processed by the proper mechanical methods in the mechanized farming systems. Agricultural crops might be injured or deformed through various working stages due to static or dynamic forces of machines. Mechanical forces had to be applied with proper degrees to the agricultural crops in incoincidence with properties of crops without any damage of crops so as to increase the work efficiency qualitatively. Knowledges of mechanical properties of agricultural materials are essential to prevent of agricultural crops in relation with mechanical farming system. This study was carried out to examine and analyze the creep behavior of the rice stalk on growing and harvesting periods by mechanical model with computer measurement system in radial directional compressive force and bending force. The creep behavior of the rice stalk could be predicted precisely and its results approached closely to the measured values. The creep behaviors were increased greatly with increase of compressive force, namely, the steady state creep behavior occurred at the force less then 25N and the logarithmic creep behavior at the force bigger than 30N. The instantaneous elastic modulus $E_o$ and the retardation time ${\tau}_K$ were increased together with increase of applied forces, meanwhile the retarded elastic modulus $E_r$ and viscosity ${\eta}_v$ were decreased with increase of applied forces in mechanical model being expected the creep behavior in relation with the level of applied forces, which was well explained that the rice stalk might be visvo-elastic material. In the creep test along the stalk portion with compressive force and bending force, the intermediate portion showed greatest values and also the lower portion showed the least values, which implied that the intermediate portions of rice stalk were very weak. The steady state creep behavior occured at the intermediate portion and the upper portion in the rice stalk at the compressive force larger than 25.0N, which showed the possibility of injury due to external forces.

• Korean Journal of Materials Research
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• v.10 no.11
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• pp.778-783
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• 2000

Effects of the $Al_2$O$_3$surface protective layer, deposited on the SnO$_2$sensing layer by aerosol flame deposition (AFD) method, on the sensing properties of SnO$_2$thin film ags sensors were investigated.Effects of Pt doping to the $Al_2$O$_3$surface protective layer on the selectivity of CH$_4$ gas were also investigated. 0.3$\mu\textrm{m}$ thick SnO$_2$thin sensing layers on Pt electrodes were prepared by R.F. magnetron sputtering with R.F. power of 50 W, at working pressure of 4mTorr, and at 20$0^{\circ}C$ for 30 min. $Al_2$O$_3$surface protective layers on SnO$_2$layers were prepared by AFD using a diluted aluminum nitrade (Al(NO$_3$).9$H_2O$) solution. The sensitivity of CO gas in the SnO$_2$gas sensor with an $Al_2$O$_3$surface protective layer was significantly decreased. But that of CH$_4$gas remained almost same with pure SnO$_2$gas sensor. This result shows that the selectivity of CH$_4$gas is increased because of the $Al_2$O$_3$surface protective layer. In the case of SnO$_2$gas sensors with Pt-doped $Al_2$O$_3$surface protective layers, low sensing property to CO gas and high sensing property to CH$_4$were observed. This results in the increasing of selectivity of CH$_4$gas selectivity are discussed.