• Journal of the Korean Academy of Pediatric Dentistry
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• v.33 no.2
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• pp.281-289
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• 2006

Topical fluoride application for children is a widely performed procedure in the field of Pediatric Dentistry for its dental caries prevention effects However, it is recently recognized as having some unwanted effects on several esthetic restorative materials, the author immersed glass ionomer cement, compomer and composite resin specimens in APF gel and measured the surface roughness and also, examined the specimens under the scanning eletron microscope. The followings are the results: 1. In the specimens of glass ionomer cement and compomer, APF gel 4 minute immersion group and pH cycling group show statistically significant increased surface roughness than artificial saliva immersion group (p<0.01). 2. There was no statistically significant surface roughness for composite resin in all group (p>0.05). 3. When the specimens were examined under scanning electron microscope, the surface change were in the order of glass ionomer cement, compomer, composite resin and also in the order of pH cycling group, APF gel 4 minutes immersion group, artificial saliva immersion group.

• Journal of Radiation Protection and Research
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• v.30 no.4
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• pp.175-183
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• 2005

Dose distribution of Korean radiation workers classified by occupational categories was analyzed. Statistics of the occupational radiation exposure(ORE) in 2002 of the radiation workers in diagnostic and dental radiology were obtained from the Korea Food and Drug Agency(KFDA) who maintains the database for individual radiation dose records. Corresponding statistics for the rest of radiation workers were obtained by processing the individual annual doses provided by the Korea Radioisotope Association(KRIA) after deletion of individual information. The ORE distribution was classified in term of 28 occupational categories, annual individual dose levels, age groups and gender of 52733 radiation workers as of the year of 2002. The total collective dose was 66.4 man-Sv and resulting average individual ORE was 1.26 mSv. Around 80% of the workers were exposed to minimal doses less than 1.2 mSv. However, it appeared that the recorded doses exceeded 20 mSv for 43 workers in the industrial radiography and for 147 workers in the field of radiology. Particularly, recorded doses of 23 workers in radiology exceeded the annual dose limits of 50 mSv, which is extraordinary when the working environment is considered. It is uncertain whether those doses are real or caused by careless placing of dosimeters in the imaging rooms while the X-ray units are in operation. No one in the workforce of 16 operating nuclear power plant units was exposed over 20 mSv in 2002. Number of workers was the largest in their 30's of age and the mean individual dose was the highest in their 20's. Women were around 20% of the radiation workers and their average dose was around one half of that of man workers.

• Journal of the Korean Academy of Pediatric Dentistry
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• v.29 no.1
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• pp.19-29
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• 2002

The purpose of this study was to compare the polymerization shrinkage and the compressive strength of composite and compomer cured with two different light sources ; conventional halogen-light curing unit and recently-developed plasma arc curing unit. The 'strain gauge method' was used for determination of polymerization shrinkage and the compressive strength was measured by universal testing machine. The results of the present study can be summarized as follows: 1. Filling materials in polyethylene molds showed the initial expansion in the early phase of polymerization. This was followed by the rapid contraction in volume during the first 60 seconds and gradually diminished as curing process continued. 2. The polymerization shrinkage in tooth samples was generally lower than in the mold samples. 3. The generally lower amount of linear polymerization shrinkage was observed in compomer and plasma arc curing unit group when compared to composite and conventional curing unit. 4. The higher compressive strength values was found in composite groups regardless curing methods. The results of this study strongly support the application of plasma arc system and fluoride-containing compomer in the field of clinical pediatric dentistry claiming its effectiveness in curing the esthetic dental materials and the anticariogenic capacity.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.11 no.1
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• pp.7-22
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• 1981

A morphological and positional classification was undertaken in the transcranial and transorbital views of 174 traceable films which had been selected from those of 274 patients and previous tracing was performed. For the positional analysis, the author adopted the method which is not influenced by TMJ remodelling, and for the morphological classification, made progress the general method by adding indefinite type to four basic types. The aims of this sutudy consists in performing positional and morphological analysis of condylar head and in its morphological and positional variation in symptomatic patients. I want to express my sincere gratitude to Prof. Park, Tae Won in Seoul National University, interesting me in this field researches and for his never failing interests. I would lide to thank Prof. Ahn, Hyung Kyu and Prof. You, Dong Soo for helpful discussion and critical readings. The author is also indebted to Prof. Fuchihate Hajime in Osaka University, Prof. Uemura, Shusaburo and the late Dr. Nishihara, Heihachi for fruitful discussion and encourgements.

• Journal of Dental Rehabilitation and Applied Science
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• v.34 no.1
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• pp.1-9
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• 2018

Purpose: The purpose of this study is to investigate the effect of the titanium implant soaked in saline after RBM and acid etched surface treatment on the initial osseointegration by comparing the removal torque and the surface analysis compared to the titanium implant with only RBM and acid etched surface treatment. Materials and Methods: The control group was RBM and acid etched surface treated implants (RBM + HCl), and the test group was implants soaked in saline for 2 weeks after RBM and acid etched surface treatment (RBM + HCl + Sal). The control and test group implants were placed in the left and right tibiae of 10 rabbits, respectively, and at the same time, the insertion torque (ITQ) was measured. After 10 days, the removal torque (RTQ) was measured by exposing the implant site. FE-SEM, EDS, Surface roughness and Raman spectroscopy were performed for the surface analysis of the new implant specimens used in the experiments. Results: There was significant difference in insertion torque and removal torque between control group and experimental group (P = 0.014 < 0.05). Surface roughness of experimental group is higher than control group. Conclusion: Saline soaking after RBM and acid etched surface treatment of titanium implants were positively affect the initial osseointegration as compared to titanium implants with only RBM and acid etched surface treatment.

• Korean Journal of Materials Research
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• v.27 no.12
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• pp.705-709
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• 2017

The electronic and optical characteristics of molybdenum disulphide ($MoS_2$) film significantly vary with its thickness, and thus a rapid and accurate estimation of the number of $MoS_2$ layers is critical in practical applications as well as in basic researches. Various existing methods are currently available for the thickness measurement, but each has drawbacks. Transmission electron microscopy allows actual counting of the $MoS_2$ layers, but is very complicated and requires destructive processing of the sample to the point where it will no longer be useable after characterization. Atomic force microscopy, particularly when operated in the tapping mode, is likewise time-consuming and suffers from certain anomalies caused by an improperly chosen set point, that is, free amplitude in air for the cantilever. Raman spectroscopy is a quick characterization method for identifying one to a few layers, but the laser irradiation causes structural degradation of the $MoS_2$. Optical microscopy works only when $MoS_2$ is on a silicon substrate covered with $SiO_2$ of 100~300 nm thickness. The last two optical methods are commonly limited in resolution to the micrometer range due to the diffraction limits of light. We report here a method of measuring the distribution of the number of $MoS_2$ layers using a low voltage field emission electron microscope with acceleration voltages no greater than 1 kV. We found a linear relationship between the FESEM contrast and the number of $MoS_2$ layers. This method can be used to characterize $MoS_2$ samples at nanometer-level spatial resolution, which is below the limits of other methods.

• The Korean Journal of Emergency Medical Services
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• v.22 no.3
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• pp.7-34
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• 2018

Purpose: The purposes of this research were to study the validity of the National Examination based on smart based test(SBT) by 7 types of healthcare occupation. Methods: We conducted a questionnaires survey among 1,219 people including 210 professors for all 7 types of healthcare occupation and 573 clinical specialists ; 436 students from random sampling participated and the reliability of the questionnaire was tested using Cronbach's alpha. Results: Professors from 7 types of healthcare occupation were investigated for their opinions on the introduction of the SBT system ; 65.9% of the professors answered positively on the introduction of the SBT National Examination System, while 40.1% of the clinical experts answered likewise. In particular, professors and the clinical experts recognized altogether that the multimedia questionnaire, being effective for the evaluation of clinical and practical competence of the subjects, enabling the evaluation of various areas and strengthening the school education in clinical practices, the 42.0% of the students from 7 departments answered that the future direction of the national test is in the SBT test system with significant difference (p=.000) found in students majoring in order of Emergency Medical Services, Radiology and Physical therapy, compared to students from other majors, showing the positive response to the SBT system. Conclusion: The results of this study comprehensively evaluated the positive recognition of development of multimedia items and SBT system in national examination of 7 types of healthcare occupation in professors, field specialists and students.

• The Journal of the Korea Contents Association
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• v.21 no.1
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• pp.373-382
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• 2021

This study conducted a survey to find out the opinions on oral health behavior and oral health education according to gender in health and non-health college students. According to the research results, there were many girls in the health-realted field and boys in the non-health-related college students. Among the oral health behaviors, brushing in school was common in both boys and girls in the health-related college students, and professional oral health education experiences were also found in the health-related college students. The need for oral health education among male students was 76.4% for healh-related college students, 48.3% for non-health-related college students, whereas female health-related college students showed 80.3%, and non-health -related college students were 60.4%. Participation in oral health education in order of male health-related students, male non-health-related students, female health-related students, and female non-health-related students were 81.9%, 68.1%, 84.8% and 73.3% respectively. The preferred method of oral health education was experiential education such as brushing for both male and female in the health-related college students, and lectures by dentists or dental hygienist were the highest reponse for non-health-related college students. The preferred location for oral health education was highest in schools. Through the results of this study, it was considered necessary to develop and disseminate appropriate oral health education programs according to college students' majors and gender, and to form correct oral health knowledge, attitudes and behaviors for oral health through oral health education.

• Journal of Korea Entertainment Industry Association
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• v.15 no.3
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• pp.193-202
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• 2021

The purpose of this study was to examine relation of awareness and education requirement of the 4th industrial revolution in health care students in attempt to provide basic data of determining the principle and education plan. The subject of study were 280 students of health department of H university in Gwangju and analyzed by gender and grade. The female students were positive awareness of the 4th industrial revolution and the level of influence on the major field was highest in lower grade students. The level of negative factors such as generation gap(p<0.05), gap between rich and poor (p<0.01), personal information infringement(p<0.05), decrease in existing jobs(p<0.05), and abuse of artificial intelligence(p<0.05) was highest in male students. In prepration for the 4th industrial revolution, education on bio and medical device(22.2%) was the most desired. The higher positive awareness, the higher educational demand(p<0.001). It is necessary to develop programs and various education to increase positive factors such as the creation of new jobs and improve the quality of life in the era of the 4th industrial revolution.

• Journal of Digital Convergence
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• v.20 no.2
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• pp.299-309
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• 2022

YouTube videos secure the latest trends in the field and provide viewers' preferences and non-preferences. This study analyzes the discussion of death in recent YouTube videos and explores the relationship between life, well-dying, and well-aging. The purpose of this study is to contribute to the establishment of a healthy life for Koreans by exploring relevance. The survey period and target are 13 videos uploaded on YouTube from 2019 to 2021. As a result of the investigation, it was possible to encompass 25 speakers who were discussing death centered on doctors. Video speakers in charge of various areas conducted various discussions on death from the perspective of experts. The key points are the true value of life, death that you don't need to fear, the importance of hope, the naturalness of death, etc. 11 expert perspectives are measured into 4 types based on 4 criteria: life, death, well-aging, and well-dying. Despite the limitations of studying 13 extracted at a specific time, this study revealed that YouTube videos are a place for free communication. It can contribute in part to maintaining and improving the health of our lives in the future and researching convergence.