• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.11
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• pp.1145-1151
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• 2015

High pressure components of a gas turbine engine must operate for a long life under severe conditions in order to maximize the performance and minimize the maintenance cost. Enhanced cooling design, thermal barrier coating techniques, and nickel-base superalloys have been applied for overcoming them and furthermore, material modeling, finite element analysis, statistical techniques, and etc. in design stage have been utilized widely. This article aims to evaluate the effects on the low cycle fatigue life of the high pressure turbine nozzle caused by different turbine inlet temperature profiles and installation conditions and to investigate the most favorable operating condition to the turbine nozzle. To achieve it, the structural analysis, which utilized the results of conjugate heat transfer analysis as loading boundary conditions, was performed and its results were the input for the assessment of low cycle fatigue life at several critical zones.

• Journal of the Korean Society of School Health
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• v.13 no.1
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• pp.117-129
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• 2000

The relationships between children's health behavior and variables that effect children's health behavior has been investigated in a number of previous studies. This study was conducted to examine the effects of a peer's social reinforcement on children's dental health behavior in an elementary school. The research design was a nonequivalent pre and post-test quasi-experimental design and the study subjects with one hundred and thirteen eight to nine years old children, and their mothers (57 experimental group, 56 control group) were selected as a study group. Subjects were selected by the convenience sampling method. The study was carried out in an elementary school in Namwon city, Korea, from the 26th of April to the 12th of June in 1999. Data were collected in both the pre and post-test portions. Using the "Health Belief Model", each item of the questionnaire for measurement of dental health behavior was modified and administered for the children and their mothers. The questionnaire for the measurement of dental health behavior was developed by Oh, Y.B.(1994). The Cronbach's ${\alpha}$ of the questionnaire for children were .81, and for the mother were .79. In this study, the health belief model consists of "perceived susceptibility", "perceived seriousness", "perceived barrier", "perceived salience", and "perceived benefit". The questionnaire for the children was composed of 37 items, and the questionnaire for the mother was composed of 40 items. Data were analyzed by frequency, ${\chi}^2-test$, ANOVA, Pearson's Correlation, and multiple regression analysis by a SAS program. The results of this study were summarized as follows ; 1. The first hypothesis that the experimental group would have more change in the frequency of brushing per week than that of control group was accepted(t=3.817, p=0.000). Mean tooth brushing scores in the experimental group improved significantly from pre-test to post-test, but in the control group there was no significant improvement in tooth brushing scores. 2. The second hypothesis that the experimental group would have more change in score of dental health behavior than that of control group was accepted(benefit : t=2.804, p=0.006, salience: t=2.608, p=0,010). An evaluation between the experimental group and the control group showed significant change from pre-test to post-test in health behavior scores. 3. The third hypothesis that higher scores of social reinforcement would create more change in the scores of tooth brushing frequency in the experimental group was accepted(${\beta}$=0.169, p=0.000. Multiple regression was used to examine the peer's social reinforcement scores and the relative influence of significant variables in previous ANOVA and Pearson's correlation test on children's frequency of brushing during the post-test. The results of the study indicated that the combination of social reinforcement of peers with variables pertaining to mother and householder were significantly related and effectively improved a child's tooth brushing.

• Korean Journal of Heritage: History & Science
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• v.53 no.4
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• pp.188-197
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• 2020

Termites play an important role as decomposers of the forest ecosystem, while simultaneously causing enormous damage to wooden structures. Currently, two species of subterranean termites have been reported in Korea, and termite damage to historical wooden buildings is occurring nationwide due to climate change, forest fertility, and the locational characteristics of historical wooden buildings. Subterranean termites make their nests underground or inside timber. Termites move underground and access wooden structures through the lower parts of the buildings, adjacent to the ground. Once termites attack the wooden structures, it not only spoils the authenticity of cultural heritage structure, but also hampers structural stability due to the decrease in the strength of the material. Therefore, it is important to prevent termite damage before it occurs. Chemical treatments are mainly used in Korea to control and prevent the damage. In foreign countries, physical barriers are also used to prevent entry to wooden buildings, along with chemical treatments. Physical barriers involve installing nets or particles that termites cannot pass through in the lower part of the building, around the pipes, and between the edges of the building or exterior walls and interior materials. Advantages of a physical barrier are that it is an eco-friendly method, maintains long-term effect after installation, and does not require the use of chemical treatments. Prior to applying physical barriers, studies into the characteristics of termite species must be undertaken. In this study, we evaluated the minimum passage size that each caste of Reticulitermes speratus kyushuensis can move through. We found that workers, soldiers, and secondary reproductive termites were able to pass through diameters of 0.7mm, 0.9mm, and 1.1mm respectively. Head height of termites was an important factor in determining the minimum passing size. Results from the current study will be used as a basis to design the mesh size for physical barriers to prevent damage by termites in historical wooden buildings in Korea.

• Journal of the Korean Institute of Landscape Architecture
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• v.39 no.4
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• pp.39-48
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• 2011

Korea is rapidly becoming an aging society. This study aims to examine the existing conditions of outdoor living environments to assist a healthy lifestyle for senior citizens and to determine the most influential factor in a senior-friendly outdoor space as well as to suggest improvements in existing conditions focused on the prospective senior population. This study relied on two methods: a descriptive method of researching publications and related scholastic writings and an empirical study that included a survey of present conditions and interviews with the prospective seniors and senior citizens in Daejeon. Conditions of outdoor living environments for seniors were found to be more than adequate in general. But some factors evaluated as low must be carefully tailored for seniors. First, the study showed that seniors evaluated as highest the 'use of a walkway' for a stroll and stayed outside for 1~2 hours at a time. Many vehicles parked in walkways were the most inconvenient factors in going for a walk. Second, the study showed that the evaluation of outdoor space was about average and 'sociality' was evaluated as the lowest. Third, the study showed that men evaluated lower than women 4 items: 'use and convenience of a wheelchair', 'night lighting', 'discrimination of signage at nighttime' and 'trees'. Respondents above the age of 66 are more uncomfortable with items such as 'slippery walking surface', 'stair handrail', 'discrimination of signage at nighttime' and 'direction of apartment complex' while respondents above the age of 80 are more uncomfortable with items of 'slippery walking surface', 'stair handrail' and 'discrimination of signage at nighttime'. Fourth, the evaluation by existing housing patterns was statistically significant in 20 of 22 evaluated items. This means that residents in apartment complex evaluated as high these items in general. In this study, existing outdoor living environments for the elderly did not display any immediately serious issues in the overall evaluation items. Assuming, however, that the aging population will quickly increase in the next ten years, items which are evaluated as low in descriptive statistics and items which give inconvenience to the elderly above the age of 80 in particular will need to be the first areas to be improved.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2004.11a
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• pp.159-166
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• 2004

The beach, a margin between the sea and the land, is an extremely dynamic zone, for it is here that the motion of the sea interacts with the sediment, rock of the land or the artificial barriers. In order to prohibit or retard erosions due to the extreme Typhoon or storm induced waves, man has constructed these of temporary or more permanent nature, but they caused problems of other erosions from the secondary effect of them and a bad influence on the seascape. In considering the energy available to accelerate sediment transport and erosion in the surf zone, where the waves are broken, and offshore beyond the breaker line, the wave height and the wave period should be taken account. Hence, we tried to present an applicability of the submerged artificial Bio-reefs analyzing waves by a numerical model such that they could reduce the wave power without the secondary effect and restoration of marine ecologies. A new technique of beach preservation is by artificial reefs with artificial and/or natural kelps or sea plants. By engineering the geometry of the nearshore reef, the wave attenuation ability of the feature can be optimized Higher, wider and longer reefs provide the greatest barrier against wave energy but material volumes, navigation hazards, placement methods and other factors require engineering considerations for the overall design of the nearshore reefs.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.1
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• pp.17-22
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• 2016

Flexible organic light-emitting diode (OLED) devices consist of multi-stacked thin films or layers comprising organic and inorganic materials. Due to thermal coefficient mismatch of the multi-layer films, warpage of the flexible OLED is generated during high temperature process of each layer. This warpage will create the critical issues for next production process, consequently lowering the production yield and reliability of the flexible OLED. In this study, we investigate the warpage behavior of the flexible OLED for each bonding process step of the multi-layer films using the experimental and numerical analysis. It is found that the polarizer film and barrier film show significant impact on warpage of flexible OLED, while the impact of the OCA film on warpage is negligible. The material that has the most dominant impact on the warpage is a plastic cover. In order to minimize the warpage of the flexible OLED, we estimate the optimal material properties of the plastic cover using design of experiment. It is found that the warpage of the flexible OLED is reduced to less than 1 mm using a cover plastic of optimized properties which are the elastic modulus of 4.2 GPa and thermal expansion coefficient of $20ppm/^{\circ}C$.

• Applied Chemistry for Engineering
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• v.26 no.4
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• pp.495-504
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• 2015

This work investigated the characteristics of a packed-bed plasma reactor system and the performances of the plasma reactors connected in series or in parallel for the decomposition of ethylene. Before the discharge ignition, the effective capacitance of the ${\gamma}$-alumina packed-bed plasma reactor was larger than that of the reactor without any packing, but after the ignition the effective capacitance was similar to each other, regardless of the packing. The energy of electrons created by plasma depends mainly on the electric field intensity, and was not significantly affected by the gas composition in the range of 0~20% (v/v) oxygen (nitrogen : 80~100% (v/v)). Among the various reactive species generated by plasma, ground-state atomic oxygen and ozone are understood to be primarily involved in oxidation reactions, and as the electric field intensity increases, the amount of ground-state atomic oxygen relatively decreases while that of nitrogen atom increases. Even though there are many parameters affecting the performance of the plasma reactor such as a voltage, discharge power, gas flow rate and residence time, all parameters can be integrated into a single parameter, namely, specific input energy (SIE). It was experimentally confirmed that the performances of the plasma reactors connected in series or in parallel could be treated as a function of SIE alone, which simplifies the scale-up design procedure. Besides, the ethylene decomposition results can be predicted by the calculation using the rate constant expressed as a function of SIE.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.5
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• pp.2549-2554
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• 2016

Background: Early detection remains the cornerstone of breast cancer control in terms of outcome and survival. Thus far the only breast cancer screening method proven effective is mammography. The awareness of female health care workers (HCW) about breast cancer prevention is of vital importance, as their beliefs and behavior may have a major impact on other women. This study was designed to assess mammography screening uptake among female healthcare workers at primary healthcare centers, and to identify the primary motivators and barriers that affect uptake results. Materials and Methods: A cross sectional study design was used to assess mammography screening by 299 female healthcare workers who completed a self-administered questionnaire that assessed demographics, screening uptake, motivators and barriers. Results: The mean age was 46 years (within age of risk). The majority (95.1%) demonstrated adequate knowledge about breast cancer and mammography screening and 50% of the participants reported having at least one mammogram; however only 21% of them had regularly scheduled mammograms. The most frequent reported motivator was the perceived benefit that early detection of breast cancer is important for its management (89.6%), followed by the belief that mammography can detect breast cancer before its symptoms appear (84.4%). On the other hand, the most frequent barrier reported was being busy (46.7%), followed by the lack of perceived susceptibility (41.5%). Conclusions: Mammography screening was found to be sub-optimal in a population of HCW's with 50 % stating that they received a mammogram at least once, and a minority reported regular screening. There is a pressing need for educational programs aimed at removing the barriers that limit compliance with recommendations for mammography screening, and to emphasize the importance of early detection in breast cancer treatment. Ensuring the availability and accessibility of screening services, particularly for healthcare workers within their work settings are other important factors that would improve the acceptance and compliance for mammography screening programs.

• Journal of muscle and joint health
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• v.5 no.2
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• pp.174-190
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• 1998

Osteoporosis has been known as a common complication of rheumatoid arthritis and a major preventable health problem. Lots of studios have demonstrated that changes in life style can help delay or prevent osteoporosis. Therefore nursing intervention related osteoporosis prevention have consisted of education programs aimed at changing dietary and exercise habit. However knowledge gained from education haven't always leaded to behavior change. Therefore it is important to consider other psychological variables in effecting behavior change. Numerous research have found self efficacy and health belief to be an important factor in individual decision making behavior. The purpose of the study was to develop health belief and efficacy expectation promoting program based on Health Belief Model & Self Efficacy Model and to investigate its effects in women with rheumatoid arthritis. For this purpose, one group pretest-post design was used. The subject of the study were 16 women with rheumatoid arthritis in Pusan city and data collection was carried out from April, 1997 to May, 1998. The intervention program was consisted of educating on osteoporosis and enhancing and reinforcing self efficacy by verbal persuasion during the period of 4 weeks. The instruments were used to collect data in this study were Osteoporosis Health Belief Scale, Osteoporosis Self Efficacy Scale, and Osteoporosis Preventive Behavior Scale. Data was analyzed by Wilcoxon signed rank test using SPSS $PC^+$ program. The results are as follows : 1) The behavior should be increased after intervention was supported(Z=-3.5162, p=.0004, diet : Z=-3.2942, p=.0010, exercise). 2) The sub-hypothesis that perceived sensitivity should be increased after intervention was supported (Z=-2.3854, p=.0171). 3) The sub-hypothesis that perceived severity should be increased after intervention was rejected(Z=-1.4327, p=.1520). 4) The sub-hypothesis that perceived benefit should be increased after intervention was supported(Z=-2.6410, p=.0083). 5) The sub-hypothesis that perceived barrier should be decreased after intervention was supported (Z=-2.4138, p=.0158). 6) The sub-hypothesis that efficacy expectation should be increased after intervention was supported(Z=-3.5162, p=.0004). As a conclusion, it was found that health belief and self efficacy promoting program was an effective nursing intervention for preventing osteoporosis of rheumatoid arthritis.

• Economic and Environmental Geology
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• v.51 no.2
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• pp.131-147
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• 2018

In the present study, the safety of the near surface disposal facility for low- and intermediate-level radioactive waste (LILW) is examined based on the fluid-flow simulation model. The effects of the structural design and hydrological properties of the disposal system are quantitatively evaluated by estimating the flux of infiltrated water at the boundary of the structure. Additionally, the safety margins of the disposal system, especially for the cover layer and vault, are determined by applying the various scenarios with consideration of possible facility designs and precipitation conditions. The overall results suggest that the disposal system used in this study is sufficiently suitable for the safe operation of the facility. In addition, it is confirmed that the soundness of both the cover layer and the vault have great impact on the safety of the facility. Especially, as shown in the vault degradation scenario, capability of the concrete barrier of the vault make more positive contribution on the safe operation of the facility compared to that of the cover layer.