• Journal of Oral Medicine and Pain
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• v.40 no.2
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• pp.41-46
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• 2015

Purpose: This study was performed to investigate a correlation among oral hygiene habits, dryness of mouth, and self-perceived oral malodor and therefore to find out self-care methods which could be a help to reduce oral malodor. Methods: A survey of 296 dental undergraduate students of School of Dentistry, Pusan National University, who wrote consents voluntarily and participated in this study, was conducted using a questionnaire consisting of 17 questions and analyzed to investigate a correlation among oral hygiene habits (frequency of tooth brushing, water gargling, and drinking water, etc.), dryness of mouth indicating the amount of salivary secretion, and self-perceived oral malodor. Results: There was no significant correlation between mechanical cleaning factors and self-perceived oral malodor. The factor showing a strong correlation with severe self-perceived oral malodor was dryness of mouth (p=0.000). Conclusions: There was no correlation between mechanical cleaning habits and self-perceived oral malodor. Participants who felt self-perceived oral malodor more tended to have rather good mechanical cleaning habits. The factor showing a strong correlation with severe self-perceived oral malodor was dryness of mouth. Therefore trying to increase salivary secretion is considered to be a help to reduce self-perceived halitosis.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.458.2-458.2
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• 2014

We have demonstrated that simple brush-painted Ti-doped $In_2O_3$(TIO) films can be used as a cost effective transparent anodes for organic solar cells (OSCs). We examined the RTA effects on the electrical, optical, and structural properties of the brush painted TIO electrodes. By the direct brushing of TIO nanoparticle ink and rapid thermal annealing (RTA), we can simply obtain TIO electrodes with a low sheet resistance of 28.25 Ohm/square and a high optical transmittance of 85.48% under atmospheric ambient conditions. Furthermore, improvements in the connectivity of the TIO nano-particles in the top region during the RTA process play an important role in reducing the resistivity of the brush-painted TIO anode. In particular, the brush painted TIO films showed a much higher mobility ($33.4cm^2/V-s$) than that of previously reported solution-process transparent oxide films ($1{\sim}5cm^2/V-s$) due to the effects of the Ti dopant with higher Lewis acid strength (3.06) and the reduced contact resistance of TIO nanoparticles. The OSCs fabricated on the brush-painted TIO films exhibited cell-performance with an open circuit voltage (Voc) of 0.61 V, shot circuit current (Jsc) of $7.90mA/cm^2$, fill factor (FF) of 61%, and power conversion efficiency (PCE) of 2.94%. This indicates that brush-painted TIO film is a promising cost-effective transparent electrode for printing-based OSCs with its simple process and high performance.

• 보존과학연구
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• s.30
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• pp.149-155
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• 2009

Annals of the Joseon Dynasty were composed of 1,229 volumes, and the 475 copies of total annals were wax-treated. Compared to non-wax treated copies, waxed volume of annals were seriously damaged such as crack, stick, discoloration to brown or black, and partially degradation. It is believed that the purpose of wax treatment for some volumes in the annals of the Joseon Dynasty is to prevent paper to deteriorate and to keep for the long time. But, beeswax could be deteriorated itself more rapidly. As a result, the waxed volume was much more damaged than non-waxed volume. Therefore, the investigation of decomposition and deterioration mechanism of beeswax-treated paper which might be used in waxed volume of the annals of the Joseon Dynasty must be done in order to prevent further decomposition and to restore the degraded wax-treated copies of the annals. For basis data of this purpose, physical properties of beeswax-treated paper be analyzed by coating methods. In result, sample products was manufactured reproducibility in lab scale. Specially, beeswax-treated method improved a orientation of papers. And the brushing method was stronger than the dipping method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2802-2811
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• 2013

This study was conducted to provide basic data for improvement of oral health of workers, by investigating oral health behaviors of industrial workers. About sixty percent(60.9%) of subjects experienced in having dental examinations and 54.3% of them didn't receive follow-up treatments after the dental examinations. Also, those who brushed teeth twice per week(58.6%) and averagely, earned 2~3 million won of monthly income(p<.01), showed a higher frequency of tooth brushing. Experienced workers(p<.01) were more interested in oral health. Those who were engaged in other jobs and had less than 10~20 years of experience(p<.05), had lots of experience in staying away from work. More aged group recognized that oral health education is necessary(p<.05). The population of oral examination and health instruction may have a favorable impact on maintenance of oral health status and improvement in quality of life.

• Journal of Korea Foundry Society
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• v.33 no.2
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• pp.69-74
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• 2013

Silicon (Si) wafer was grown by using direct growth from Si melt and contaminations of wafer during the process were investigated. In our process, BN was coated inside of all graphite parts including crucible in system to prevent carbon contamination. In addition, coated BN layer enhance the wettability, which ensures the favorable shape of grown wafer by proper flow of Si melt in casting mold. As a result, polycrystalline silicon wafer with dimension of $156{\times}156$ mm and thickness of $300{\pm}20$ um was successively obtained. There were, however, severe contaminations such as BN and SiC on surface of the as-grown wafer. While BN powders were easily removed by brushing surface, SiC could not be eliminated. As a result of BN analysis, C source for SiC was from binder contained in BN slurry. Therefore, to eliminate those C sources, additional flushing process was carried out before Si was melted. By adding 3-times flushing processes, SiC was not detected on the surface of as-grown Si wafer. Polycrystalline Si wafer directly grown from Si melt in this study can be applied for the cost-effective Si solar cells.

• Journal of the Korean Electrochemical Society
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• v.11 no.1
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• pp.16-21
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• 2008

The key component of a direct methanol fuel cell (DMFC) is the membrane electrode assembly (MEA), which comprises a polymer electrolyte membrane and catalyst layers (anode and cathode electrode). Generally the catalyst layer is coated on the porous electrode supporter (e.g. carbon paper or cloth) using various coating methods such as brushing, decal transfer, spray coating and screen printing methods. However, these methods were disadvantageous in terms of the uniformity of catalyst layer thickness, catalyst loss, and coating time. In this work, we used bar-coating method which can prepare the catalyst layer with uniform thickness for MEA of DMFC. The surface and cross-section morphologies of the catalyst layers were observed by SEM. The performances and resistance of the MEAs were investigated through a single cell evaluation and impedance analyzer.

• Journal of Korean society of Dental Hygiene
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• v.9 no.3
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• pp.403-414
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• 2009

Objectives : This research aimed at investigating middle school students' knowledge and behavior of oral hygiene according to the knowledge level of parents on this ground, provide basic data for establishing a more effective school and home oral hygiene education program for students. Methods : Students were selected from four secondary schools in J city by convenience sampling, which is non probability sampling; then, the final analysis was performed on 272 self-administered questionnaires. For statistical analysis, SPSS 10.0 for Windows was used to carry out frequency analysis and chi-square test at the 0.05 significance level in determining statistical significance. Results : 1. 50.0% had periodontal disease caused by 'weak periodontal', in the case of the father of academic ability was middle school graduated. 2. Showed lowly what is behavior prevention as regularly oral examination for the oral health, in the case of the parents's academic ability was low(in the case of the mother's academic ability was middle school graduated, 34.5% received regular oral examination every three months). 3. In the case of, the father and mother of academic ability was middle school graduated showed 50%, 44.8% about the teeth never important in the life. 4. In the case of, the father and mother of academic ability was middle school graduated showed 37.5%, 31.0% about time for the tooth brushing is under 1 minute per one time. Conclusions : It's very important for middle school student's oral health that the oral health education and oral hygiene attitude in their home. especially middle school student's attitude was controlled by parents' knowledge level. This like basic data will be useful in establishing program of school oral health and individual oral hygiene attitude in their home.

• Journal of Korean society of Dental Hygiene
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• v.11 no.5
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• pp.603-613
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• 2011

Objectives : This study is to investigate factors that predispose the oral health education patterns of teachers at preschool institutions such as kindergartens and day nurseries, for which a comparison was made among the patterns, whereto the PRECEDE model was applied. Methods : A survey was conducted by two visits, a preliminary survey and a main survey, and teachers at the foregoing institutions personally filled in the questionnaire. Results : 1. With relation to epidemiological and social diagnosis, the largest number of respondents (53.7%) agreed on the need for oral health education, but at the same time, the largest number of respondents (40.3%) was unsatisfactory with oral health education given by them. 2. With relation to behavioral diagnosis, there were many cases where respondents taught their students to brush their teeth after meals and snacks. Oral health education was focused on safety and injuries. There was no significant intergroup difference (p>0.05). 3. Predisposing factors (a subcategory of educational diagnosis) showed the following results: As for the frequency of oral health education, most respondents at both institutions answered preferred once every six month (p>0.05). In the case of oral health checkup, 75.4% of respondents at kindergartens preferred once a year. 72.2% of respondents at day nurseries preferred the same frequency. They showed a statistically significant difference (p<0.05). In enabling factors, it was found that most respondents at both institutions collected information and teaching materials from mass media and public health centers respectively. In enabling factors, insufficient teaching materials, media and knowledge were found to be obstacles to oral health education. Conclusions : Oral healthcare providers' cooperation is required to diversify away from tooth brushing-centered education and to enrich oral health education. In addition, continuous supplements are required to make teachers at preschool institutions acquire expert knowledge and give oral health education with confidence. Moreover, it needs to train them for various education programs as well as to support them with educational media. Lastly, family members' cooperation is required to develop oral health education programs.

• Journal of Korean society of Dental Hygiene
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• v.11 no.5
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• pp.801-809
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• 2011

Objectives : The Purpose of this study is to apply an oral health education program to the high school students, to analyze their oral health knowledge and changes of behaviors, and to examine oral health education for effective, thus using all of those results as the basic data for developing materials on their oral health education. Methods : The study was conducted on the freshmen and women of M high student in Seoul City. They were in total 85 student, consisting of 77 of male student(90.6%) and 8 of female student(9.4%). Knowledge survey contained 38 questions including such as dental common knowledge, dental caries, and periodontal disease, while behaviors survey did 24 questions including such as tooth-brushing, brush selection and management, and prevention of oral disease. Results : First, oral health education had brought to improve oral health knowledge for high school students. Second, even with the improvement of oral health behaviors through the education, there was not statistically significant on behaviors such as the regular checkups and the usage of dental floss. And third, the students in general were satisfied with the oral health education. Conclusions : First, the oral health education being conducted in kindergarten and elementary school should be continued or expanded into the adolescence. Second, the oral health education should be focused efficiently on the learning objective demanding for a change of behavior through the repeated education, for which the education that is right for the high school students should be done. And third, for the effective oral health education in high school, the media that could cause interests should be developed.

• Journal of Korean society of Dental Hygiene
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• v.17 no.4
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• pp.669-680
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• 2017

Objectives: The objective of this study was to investigate the correlation between demographic factors and oral health factors and mental health factors in Korean adolescents. Methods: The study was based on the 11th Korea Youth Risk Behavior Web-Based Survey (2015). The final participation rate in the survey was 96.7%. of a total of 70.362 adolescents (age, 12~18 years) who had participated in the survey, 68,043 adolescents were selected for analysis. Results:As a result of examining the stress awareness of adolescents and the experience of oral disease symptoms, it was found that the number of brushing times per day was less than 1 time (p<0.001), tingling and throbbing (p<0.001), gum pain & blood (p<0.001) and bad breath (p<0.001) were more stressed than those who had experience. On the other hand, the lack of experience in oral health education was more stressful (p<0.001). As a result of examining the factors influencing subjective happiness, it was found that the female, the lower the grade, the higher the academic performance and economic level, the less experience of oral disease in the last one year, The level of awareness was high. Conclusions: These results indicate that the demographic factors, mental health factors, and oral health factors of adolescents are correlated to one another. Therefore, when developing a program for promoting adolescent health or establishing a national business plan, it should be considered in a multi-faceted way.