• Restorative Dentistry and Endodontics
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• 제24권2호
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• pp.330-336
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• 1999

In biological systems, the mineral that forms hard tissue is of an apatitic nature, and hydroxyapatite($Ca_5OH(PO_4)_3$: HA) is generally considered as the prototype for such a mineral. Thus, the precipitation of HA, having biological implications, has been the subject of several investigations. Crystal growth studies using HA seeds in supersaturated solutions have enhanced our understanding of the process and mechanism involved in seeded crystal growth. From these studies, it has become apparent that the precipitation rate of HA onto the seed crystals depends on the various conditions, especially on the additives. The relation between the supersaturated solution containing fluoride and the process of HA crystal growth enhances the understanding of mechanism of HA crystal growth. Until recently, the studies have been on the crystal growth of enamel minerals and synthetic HA seeds in the supersaturated solution containing 1~2 ppm fluoride. The purpose of the present investigation is to study the effect that fluoride of high concentration has on the crystal growth kinetics of HA. In order to produce the composition found in the secretory enamel fluid, experimental solutions of 1mM Ca, 3mM P, and 100mM Tris as background electrolyte were used. Then this experimental solutions were added to 0, 2, 4, 6, 8, 10 ppm fluoride. The effect of fluoride at high concentrations on the precipitation was examined in a bench-top crystal growth model adopting a miniaturized reaction column. Chemical analysis was employed for characterization of working solutions before and after the experimentation. Remarkable findings were : 1) the amount of crystal growth was gradually accelerated as the fluoride concentration increased until 6 ppm, but decreased in 8 and 10 ppm fluoride; 2) the amount of fluoride ion consumed in crystal formation was constant despite the increase in fluoride concentration.

• Journal of the Korean Society of Clothing and Textiles
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• 제21권4호
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• pp.769-781
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• 1997

The purpose of this research is to show how to use the patternist's CAD system in order to make design patterns efficiantly. Using the PAD System Technologies company's PAD System Module, which is very officiant in designing patterns, the basic pattern or design pattern can be designed and applyed to the Sample Module, thus, then it could manufacture, retouch or choose a model, making it posible to go to the next level which is seam patterns for industrial use. By understanding the change of the design that is chosen through the design pattern making and Sample Module process', this study is presentated a plan on how to utilize the patternist's working adaption ability by the CAD system, and also considered the problems in using it. Ability of Design Confrontation of CAD System: 1) The result of an operation can be saved and retouched. On a saved list the patterns can be chosen and changed, thus, making it posible to complete a design very quickly. 2) When sewing every designed pattern in Sample Module, the model can be operated merely by selecting each sewing position, thus creating the same effect of a designer's muslin sample process in a much lesser time. Point at issue in the utilization CAD system: 1) When combining two darts into one place the amounts of darts that are already these have to be erasers, and then, the two darts points are moved that place, thus, containing them, which is very conplicated. 2) When making a gathering, because system can only be recognized in a opend line, the pattern should be separated in order to put a gathering inside a pattern. 3) In order to readjust the amounte of dart. The dart is erased first and then made new dart again. 4) When making tucks in a Sample Module, the form that gets narrow towards the pivot point can not be recognized so the sewing lines of the tucks is adjusted into parallel lines. 5) The Sample Module 3D operation can not attach the bodice to the shirts, instead they become fixed into each other. In the case of shoulder line tucks the amounts of pleats can not be expanded draperary naturally, thus, making it hard to showing the silhouette accurately. If these problems are solved, especially if the silhouette of a model can be created to have natural drapery in the 3D Module, models can be shown on the screen in possible to compare and examine even a change of a detail, by designing this 3D Module Production sample process will be more effective, thus, making the CAD system more useful in sewing design process.

• Journal of Bio-Environment Control
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• 제13권1호
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• pp.1-7
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• 2004

This study is kinematics for the manipulator development of cucumber harvesting. A theory value was verified by repeated error measurement after the forward kinematics or inverse kinematics analysis of manipulator. Manipulator is consisted of one perpendicular link and two revolution link. The transformation of manipulator can be valued by kinematics using Denavit-Hartenberg parameter. The value of inverse kinematics which is solved by three angles faction shows two types. Repeated errors refered maximum 2.60 mm, 2.05mm and 1.55 mm according to X, Y, Z axis. In this study, the actual coordinates of maximum point and minimum point were agreement in the forward kinematics or inverse kinematics. The results of repeated error measurement were reflect to be smaller compared to a diameter of cucumber. measurement errors were determined by experimented errors during the test. For reducing errors of manipulator and improving work efficiency, the number of link should be reduced and breeding and cultural environment should be considered to reduce the weight and use the hard stuff. The velocity of motor for working should be considered, too.

• The Journal of the Korea Contents Association
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• 제15권1호
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• pp.366-378
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• 2015

The purpose of this study conducted in the United States was to identify the level of role stressors among professions at centers for independent living and to investigate the relationship between role stressors and burnout at the target population. A total of 218 professions completed a web-based and hard copy survey. The participants reported a mean (standard deviation) score of 22.48 (5.80) for the role conflict dimension, 22.20 (4.30) for the role ambiguity dimension, and 9.14 (2.55) for the role overload. Demographic assessment of the differences on the mean score of the three role stressors revealed significant associations with that age, job title, highest level of education, years of human service experience and working hours per week for role conflict/role ambiguity, and experience in human service for role overload. The role conflict, ambiguity, and overload stressors were significant predictors of emotional exhaustion and depersonalization explaining 26% and 14% of the variance, respectively. None of the stressors significant predicted personal accomplishment. The results indicate that role conflict, ambiguity, and overload are important predictors of burnout among professions at centers for independent living.

• Journal of Environmental Health Sciences
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• 제47권5호
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• pp.432-445
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• 2021

Background: The European Centre for Ecotoxicology and Toxicology of Chemicals' Targeted Risk Assessment (ECETOC TRA) tool has been recognized by EU REACH as a preferred approach for calculating worker health risks from chemicals. Objectives: The applicability of the ECETOC TRA to occupational exposure estimation from industrial uses of methanol was studied by inputting surveyed and varied parameters for TRA estimation as well as through comparison with measured data. Methods: Information on uses of methanol was collected from seven working environment monitoring reports along with the measured exposure data. Input parameters for TRA estimation such as operating conditions (OCs), risk management measures (RMMs) and process categories (PROCs) were surveyed. To compare with measured exposures, parameters from the surveyed conditions of ventilation but no use of respiratory protection were applied. Results: PROCs 4, 5, 8a, 10, and 15 were assigned to ten uses of methanol. The uses include as a solvent for manufacturing sun cream, surfactants, dyestuffs, films and adhesives. Methanol was also used as a component in a release agent, hardening media and mold wash for cast products as well as a component of hard-coating solution and a viscosity-controlling agent for manufacturing glass lenses. PROC 8a and PROC 10 of a cast product manufacturer without LEV (local exhaust ventilation) and general ventilation as well as no respiratory protection resulted in the highest exposure to methanol. Assuming the identical worst OCs and RMMs for all uses, exposures from PROC 5, 8a, and 10 were the same and the highest followed by PROC 4 and 15. The estimation resulted in higher exposures in nine uses except one use where measured exposure approximated exposures without RMMs. Conclusions: The role of ECETOC TRA as a conservative exposure assessment tool was confirmed by comparison with measured data. Moreover, it can guide which RMMs should be applied for the safe use of methanol.

• Journal of the Korean BIBLIA Society for library and Information Science
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• 제32권3호
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• pp.93-114
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• 2021

COVID-19 has been affecting the library, not to mention society as a whole. Especially, there are many changes in the role and service of the university libraries as all the classes of the universities are turned into non-face-to-face and the use of the university libraries is restricted. The changes in users' use of information and communication behavior due to COVID-19 could be an opportunity for new utilization of human and material resources the university libraries have and for the development of services. However, on the contrary, the university libraries could face another crisis if they fail to respond appropriately to current changes. Therefore, it is necessary to grasp, analyze the impact of COVID-19 and plan how to respond. A survey on the effects of COVID-19 and the response of the university libraries and the perceptions of the university libraries found that most university libraries are responding appropriately to COVID-19. However, a survey on the perceptions of the present and future of the university libraries under COVID-19 showed that many survey respondents think COVID-19 would have a negative impact on the university libraries. This means that the changes caused by COVID-19 are causing a crisis and anxiety in the university libraries. Therefore, by working hard together, the university libraries need to present the university libraries' new role, service and direction in the post-COVID-19 era as well as responding to the current situation.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제20권6호
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• pp.573-578
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• 2019

This paper applied to the Korean Lesson using PBL(Problem-Based Learning) based on Google Classroom for Mongolians. Recently, Mongolians trying to learn Korean because of Korean wave. This study aims to develop the online problem-based learning model as a way to develop the creative problem-solving ability of Mongolians who want to learn Korean. We applied 3 problems for 9 weeks. This study shows that the participants experienced the effectiveness of Google Classroom and PBL in many ways, 93% of the participants reported that Google Classroom and PBL helped them to learn Korean easily and interesting distance learning model, 90% of the participants prefer to explore Googlish programs and online learning, 85% of them said that increased interaction others in online environment easily. 100% of them said that thankful for learning Korean with Online tutor anytime on Google Classroom. Truly, 86% of them said PBL was hard to generate and understand it because very new instruction for them and working with team in online learning environment. The study showed that members of Korean Lesson experienced various effects such as understanding of learning contents, understanding of cooperative learning, practical experience, creative problem solving ability, presentation skill, communication ability, self - directed learning ability, self - confidence through Google Classroom based PBL.

• 한국노년학
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• 제38권4호
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• pp.1149-1171
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• 2018

The purpose of this study is to increase understanding of the social intervention for severely isolated older adults who live alone and are in serious isolation as if they were 'hidden'. Through qualitative descriptive methods, it intends to describe how social workers in the "Making Friends of Older Adults who Live Alone" project have perceived older adults living alone in serious isolated situation, whether there have been changes in the perception of the elderly according to the progress of the project, and what kinds of experiences these social workers have had while providing case management to older adults. In-depth interviews with 40 social workers, case management records of 70 senior citizens, and research journals were collected and analyzed using qualitative content analysis methods. The results of data analysis were presented in two categories and four subcategories each. Based on the research findings, four kinds of implications were suggested.

• The Journal of the Korea Contents Association
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• 제21권12호
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• pp.119-131
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• 2021

The purpose of this study is to improve the curriculum of major subjects by constructing and applying design thinking centered 'early childhood language education' for prospective kindergarten teachers, and to cultivate their teaching ability in the classroom. As a result of the study, it is as follows. First, in the improvement of 'early childhood language education' subjects centered on design thinking, the "plan" stage recognizes the problem of interest in language education and the execution of language areas. In the "action" step, they created a interesting stationery for plays that can be actively expressed for young children who are hard to write. In the "re-action after reflection" steps, they have developed creative writing based on the diverse experience of the who have been working on a kindergarten field practice, Second, The meaning of the implementation for the major classes based on the design thinking is listening to young children than given practice, and self-reflection and growth through sympathy and cooperation. The implications of this study are needed to change the various major classes and the experience of problem solving is that it is also helpful for the autonomy and expertise of prospective kindergarten teachers.

• Safety and Health at Work
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• 제13권2호
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• pp.163-169
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• 2022

Background: It is estimated that about 13 million artisanal and small-scale miners carry out their activities under harsh, precarious, unfriendly, and risky conditions. Yet, our understanding of the extent to which these workers use personal protective equipment (PPE) and navigate through the various risks and hazards they face is still limited. This article has two main objectives. First, it explores the extent of usage of PPE among artisanal and small-scale miners for the prevention of hazards and risks. Second, it examines the coping strategies used by these miners as a response to experiences of occupational injuries and risks Methods: A cross-sectional survey of small-scale miners was conducted in six communities across three districts in Ghana, West Africa. The mixed methods approach was adopted. A total of 148 small-scale miners participated in the study. Six focus group discussions (FGDs) were held across the six communities. The data were analysed using descriptive statistics. Chi-square tests were used to analyse the relationship between some socio-demographic characteristics (sex, age, and educational background) and the usage of PPE. Open-ended questions and responses from FGDs were analysed based on the content and verbatim quotations from miners. Results: Findings suggest that 78% of the miners interviewed do not use the appropriate PPE citing reasons such as cost, and their personal discomfort associated with use of PPE. There was no significant relationship between socio-demographic characteristics (i.e., sex, age, education and major mining activity) and the usage of PPE. The study further revealed four main coping strategies used by miners to handle the risks. These are rest, taking unprescribed medication and hard drugs, registration with health insurance scheme and savings and investments. Conclusion: This study shows that very few artisanal miners use PPE despite the significant hazards and risks to which they are exposed. The study recommends to the government to put in place measures to ensure that miners adhere to health and safety regulations before undertaking mining activities. This means that health and safety plans and use of PPE should be linked to the license acquisition process for miners.