• Journal of dental hygiene science
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• v.14 no.4
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• pp.488-494
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• 2014

The purpose of this study is to analyze the association of oral health of the elderly and oral health quality of life. The subjects of this study were 282 participants who received the fluoride application and the scaling service through program targeting elderly people carried out by a public health center located in Gyeongsangbuk-do Province. Data were collected from January 2011 to December 2011. The result of comparing subscale scores of quality of life related to oral health depending on socioeconomic characteristics showed that functional limitation scores were lower as educational level got higher. The result of comparing subscale scores of quality of life related to oral health depending on status of oral health and frequency of tooth brushing showed that quality in functional limitations, physical pain, psychological discomfort, physical disability, psychological disability, social disability and handicap scores were lower as the number of cavities got more. The result of multiple regression analysis to identify the factors affecting the quality of life related to oral health showed that the number of cavities and installation of denture were significant variables. The results of this study showed that there was significant association of oral health status and oral health related quality of life of the elderly. In order to maintain the oral health related quality of life, it is important to keep many number of residual teeth even if a person gets older and to support the installation of dentures if necessary.

• Journal of dental hygiene science
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• v.14 no.4
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• pp.442-447
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• 2014

The aim of this study was to analyze perception of risk and using status of hand-held dental x-ray unit among dental hygienists in metropolitan area. This research was based on perception of risk and using status of hand-held dental x-ray unit survey in 257 dental hygienists from July 7 to 31, 2014. Data were analyzed with t-test, one way ANOVA, and multivariable logistic regression analysis using SPSS Windows 21.0 program and significance level was set at p<0.05. The hand-held dental x-ray unit to cover all type patients was 24.8%. The 62.6% of patients and 81.3% of operator doesn't wear lead apron, the experience rate of radiation education was 40.1%. The average of risk perception was 3.08 points. The associated factors of risk perception were career, number of radiation exposure per day, and possession of fixed x-ray unit. The increased of accumulated dose when the occupationally exposed work continues, it is necessary to effort of defense against dental radiation.

• Asian Journal of Turfgrass Science
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• v.26 no.1
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• pp.67-71
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• 2012

Organic fertilizers are divided into natural organic and synthetic organics. The benefits of natural organic fertilizer were reported from the previous researches. The previous researches have reported that clippings are nitrogen source for turfgrass growth. However, the limited research results about clippings as a source of natural organic fertilizers were reported. The objective of the research to investigate effects of liquid fertilizer produced from fermented clippings for creeping bentgrass growth. Liquid fertilizer (LF) produced was used for the research to be compared with urea and two natural organic fertilizers of different source (NO-1 and NO-2). Kentucky bluegrass (Poa pratensis L., Midnight) was used for the study. Turfgrass quality was measured by visual evaluation every two weeks from June to October, 2011 using a scale of 1 to 9 (1=worst, 6=acceptable, and 9=best). LF produced greater turfgrass quality than acceptable quality, especially with the summer period while urea and NO produced lower turfgrass quality than acceptable quality of 6. LF had less quality alteration than urea and NO during the study. Based on the result of the study, LF are more stable to maintain turfgrass quality than urea and NO.

• Journal of dental hygiene science
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• v.14 no.4
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• pp.433-441
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• 2014

This study was aimed to analyze factors affecting intention on clinical application by task autonomy of dental hygienists, expected effect and obstructive factor on clinical application of assessment, dental hygiene diagnosis, planning, implementation, and evaluation (ADPIE). Meanwhile, it proved mediating effects of "attitude toward ADPIE" when it came to "intention on clinical application". The data was collected from 237 dental personnel in capital region from March 28, 2014 to May 2, 2014. To analyze the suitability of a theoretical model and hypothesis testing, SPSS 21.0 and AMOS 18.0 program were used. The theoretical model was accepted as it resulted in ${\chi}^2=421.67$ while showing goodness of fit index=0.858, comparative fit index=0.915, Tucker-Lewis index=0.896, root mean square residual=0.039, and root mean square error of approximation=0.099. The result showed "task autonomy of dental hygienists (${\beta}=0.398$, p<0.05)" and "expected effect on ADPIE (${\beta}=0.363$, p<0.01)" had a positive effect on "attitude toward ADPIE". Also, "attitude toward ADPIE" had a positive effect on "intention on clinical application". In addition, "task autonomy of dental hygienists" and "expected effect on ADPIE" had an indirect influence on "intention on clinical application" via such intermediary as "attitude toward ADPIE". According to the above results, the task autonomy of dental hygienists, expected effect on ADPIE, and attitude toward ADPIE were confirmed to be significant factors when it came to the intention on its clinical application. Therefore in order to settle ADPIE in the clinical practice, improvement of task autonomy for dental hygienists as well as their expectation and attitude on ADPIE must be promoted.

• Journal of dental hygiene science
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• v.14 no.2
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• pp.230-239
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• 2014

This study is to promote awareness to be exposed to radiation with identifying knowledge, attitudes and behavior for radiation safety management of the operating room nurse and dental hygienist. And the following results were obtained through questionnaire survey to deduct the education to prevent potential risks in advance and implication to be useful on education program. First, based on the level of knowledge for radiation safety management, 10.57 for dental hygienists, 9.55 for the nurse out of 15 points (p<0.001); based on the level of attitudes for radiation safety management, 4.64 for dental hygienists, 4.67 for the nurse out of 5 points (p<0.001); and based on the level of behavior for radiation safety management, 3.27 for dental hygienists, 2.93 for the nurse out of 5 points (p<0.001). Second, the result for checking the relation with knowledge, attitudes and behavior for radiation safety management, the knowledge of radiation safety management has correlation with attitudes and behavior for radiation safety management statistically (p<0.001).

• Journal of the Korean Chemical Society
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• v.59 no.5
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• pp.454-465
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• 2015

The goal of this study is to investigate pre-service chemistry teachers’ understanding of the boiling process of a liquid mixture. We surveyed 65 students in the chemistry program of the College of Education about the boiling point of a 50%(by mole) ethanol aqueous solution and the temperature changes during heating. We then interviewed 9 of these students. According to the survey results, the percent of the pre-service teachers who thought that the boiling point of the ethanol solution would be ‘between the boiling points of ethanol and water (78-100 ℃)’ and ‘the same as that of ethanol’ were 52.3% and 35.4%, respectively. The majority of those who stated the former explained that the boiling point of the ethanol solution increased due to the effects of attraction or blocking by water molecules. Most of those who believed the latter explained that physical properties such as the boiling point would not be changed by the addition of water. With regard to the temperature change during heating, 69.2% of the teachers thought that the temperature would increase gradually while boiling, which some thought resulted from the increasing amount of water in the solution as the ethanol boiled off. Others thought that two temperature plateaus would be observed as each component of the liquid mixture underwent phase transition at its specific boiling point. When asked about the particle model of the gas phase during the boiling and evaporation process, some students drew both ethanol and water during evaporation but only ethanol when boiling. We discussed several alternative concepts of pre-service chemistry teachers about the boiling process of liquid mixtures and ways to improve their understanding.

• Tunnel and Underground Space
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• v.9 no.3
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• pp.185-193
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• 1999

This paper presents results of dynamic analysis for a bridge in intersection part of two tunnels subjected to moving vehicle load. Since such a bridge system is very unusual due to the fact that it is located in tunnel, the dynamic characteristics of the structure can not be assumed as conventional one. The structure investigated in this study it a reinforced concrete bridge in the intersection part of Namsan Tunnel-1 and Tunnel-2 in Seoul. It is supported by temporary steel structure which shall be constructed during the period of replacing lining in Tunnel-2. Dynamic analysis was carried out for the system using a finite element model constructed by general purpose FE program SAP2000. For this purpose, the structure, lining of tunnels, and surrounding rock were represented by finite elements, while the rock region it truncated and on its outer boundary viscous dampers were placed to simulate radiation of elastic waves generated tunnels. Several types of vehicle with various driving velocities were considered in this analysis. The FE model including vehicle loadings was verified by comparing calculated peak particle velocity with the measured one. From the analysis, the impart factor for the bridge was estimated as 0.21, which indicates that the use of upper bound for the impact factor in design code is reasonable for this kind of bridge system.

• Progress in Medical Physics
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• v.19 no.1
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• pp.35-41
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• 2008

The main benefit of proton therapy over photon beam radiotherapy is the absence of exit dose, which offers the opportunity for highly conformal dose distributions to target volume while simultaneously irradiating less normal tissue. For proton beam therapy two patient specific beam modifying devices are used. The aperture is used to shape the transverse extension of the proton beam to the shape of the tumor target and a patient-specific compensator attached to the block aperture when required and used to modify the beam range as required by the treatment plan for the patient. A block of range shifting material, shaped on one face in such a way that the distal end of the proton field in the patient takes the shape of the distal end of the target volume. The mechanical quality assurance of range compensator is an essential procedure to confirm the 3 dimensional patient-specific dose distributions. We proposed a new quality assurance method for range compensator based on image processing using X-ray tube of proton therapy treatment room. The depth information, boundaries of each depth of plan compensatorfile and x-ray image of compensator were analyzed and presented over 80% matching results with proposed QA program.

• Journal of Korean Society of Steel Construction
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• v.20 no.2
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• pp.237-246
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• 2008

The cross-sections of continuous multi-span beams sometimes suddenly increase, or become stepped, at the interior supports of continuous beams to resist high negative moments. The three-dimensional finite-element program ABAQUS (2006) was used to analytically investigate the inelastic lateral-torsional buckling behavior of stepped beams subjected to pure bending moment and resulted in the development of design equations. The flanges of the smaller cross-section were fixed at 30.48 by 2.54 cm, whereas the width and/or thickness of the flanges of the larger cross-section varied. The web thickness and height of beam was kept at 1.65 cm and 88.9 cm, respectively. The ratios of the flange thickness, flange width, and stepped length of beams are considered analytical parameters. Two groups of 27 cases and 35 cases, respectively, were analyzed for double and single stepped beams. The combined effects of residual stresses and geometrical imperfection on inelastic lateral-torsional buckling of beams are considered. First, the distributions of residual stress of the cross-section is same as shown in Pi, etc (1995), and the initial geometric imperfection of the beam is set by central displacement equal to 0.1% of the unbraced length of beam. The new proposed equations definitely improve current design methods for the inelastic LTB problem and increase efficiency in building and bridge design. The proposed solutions can be easily used to develop new design equation for inelastic LTB resistance of stepped beams subjected to general loading condition such as a concentrated load, a series of concentrated loads or uniformly distributed load.

• Journal of Korean Society of Steel Construction
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• v.24 no.2
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• pp.163-173
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• 2012

A connection composed of a circular hollow structural section (HSS) has complicated details, and exhibits a very complex local deformation when it reaches the yield stress. Given these circumstances, proposing a simple design equation considering local deformation is difficult. The design equations of the Korea Building Code (KBC 2009) for HSS joints are simple and are very similar to those of the AISC. These design equations limit the maximum yield stress up to 360MPa and yield ratio (yield strength/tensile strength) up to 0.8. This means that the material with yield strength exceeding 360MPa could be used after verification based on the test or rational analysis for the similar connection. This paper introduces an experimental program and finite element analysis (FEA) for the circular hollow section (CHS) with a transverse gusset plate made of high-strength steel (HSB600) or structural steel (SS400) when the joints are subjected to lateral force. Comparison of the design equations with the results of FEA and test may be used for the modification of the design equations.