• Journal of the Korean Society of Manufacturing Process Engineers
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• v.9 no.5
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• pp.40-49
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• 2010

Conical involute gears are being used for marine gearboxes, automotive transmissions, and robots, and so on, but not much. As involute profile gear, conical involute gear not only can be engaged with spur and helical gear but also can be used for power transmission of parallel, crossed and skewed axis with small angle. Hence, conical involute gears are likely to develop in future. Through a study on the basic theory of conical involute gear, tooth surface compressive stress analysis was performed by using commercial modeling program, comparing before and after profile modification. As a result, it noticed that tooth profile modification is able to relieve more tooth surface compressive stress than before modification.

• 치위협보
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• s.93
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• pp.1-12
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• 2005

• Journal of Periodontal and Implant Science
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• v.3 no.1
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• pp.8.2-8.2
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• 1973

• The Journal of the Korean dental association
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• v.25 no.2 s.213
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• pp.185-193
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• 1987

• The Journal of the Korean dental association
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• v.37 no.10 s.365
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• pp.766-771
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• 1999

칫솔은 치면에 부착된 프라그 등의 부착물을 물리적으로 제거하기에 가장 합리적이고 간편하게 사용할 수 있도록 설계된 구강청소용구이다. 가장 흔하지만 무심코 지나치기 쉬운 칫솔 칫솔의 역사와 칫솔의 종류, 1300억에 이르는 칫솔시장을 분석해 본다.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.1
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• pp.85-89
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• 2000

There has recently been some trials to add the fluoride-releasing property to existing fissure sealants and some of them are already commercially available. But, some questions mat naturally be arisen regarding the potential decrease of physical properties by adding the fluoride despite its new caries-inhibiting abilities. This study was performed for the purpose of comparing the shear bond strengths of conventional composite sealant, Fluoride-releasing sealant and glass ionomer sealant, and obtained the results as fellows. 1. Two kinds of composite sealants (Helioseal and Teethmate-A) showed slightly higher bond strength than Fluoride-releasing sealant(Teethmate-F) without any significance(p>0.05). 2. Class ionomer sealant (Fuji III) was much lower than composite sealant in shear bond strength(p<0.05). 3. With the result of this study, it was found that there is little effect on retentive properties of sealants by adding fluoride to amplify the caries-inhibiting properties.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.2
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• pp.120-127
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• 2020

The aim of this study was to evaluate the antimicrobial effect of photodynamic therapy (PDT) using plaque disclosing agent, 10 - 20 mM erythrosine, as a photosensitizer. Multispecies cariogenic biofilms containing Streptococcus mutans, Lactobacillus casei and Candida albicans were formed on hydroxyapatite disc. 20 μM, 10 mM and 20 mM erythrosine were applied as a photosensitizer for 3 minutes, and then light-emitting diode (LED) irradiated for 24 seconds. Colony-forming unit (CFU) were measured and biofilms were observed using confocal laser scanning microscopy (CLSM). CFU were significantly decreased in the PDT groups using 10 - 20 mM erythrosine (10 mM, 20mM) and the results were also confirmed by CLSM. This study confirms the high antimicrobial effect of photodynamic therapy using plaque disclosing agent as a photosensitizer.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.12
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• pp.953-960
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• 2020

This paper presents an optimization of gear web design used in a main gear train of an engine reduction gearbox for a rotorcraft. The optimization involves the minimization of a total weight, transmission error, misalignment, and face load distribution factor. In particular, three design variables such as a gear web thickness, location of rim-web connection, and location of shaft-web connection were set as design parameters. In the optimization process, web, rim and shaft of gears were converted from the 3D CAD geometry model to the finite element model, and then provided as input to the gear simulation program, MASTA. Lastly, NSGA-II optimization method was used to find the best combination of design parameters. As a result of the optimization, the total weight, transmission error, misalignment, face load distribution factor were all reduced, and the maximum stress was also shown to be a safe level, confirming that the overall gear performance was improved.

• Journal of Advanced Technology Convergence
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• v.2 no.4
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• pp.49-56
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• 2023

The purpose of this study was to investigate the effectiveness and perception of eco-friendly oral products by comparing and analyzing the dental bacterial film removal rate of eco-friendly toothbrushes and general toothbrushes, and by examining the satisfaction of the research subjects with toothbrushes through questionnaires. As a result of the study, there was no significant difference in the removal rate of dental bacterial film between eco-friendly toothbrushes and general toothbrushes, so it was found that the function of eco-friendly toothbrushes was not much different from that of ordinary toothbrushes, and the satisfaction with eco-friendly toothbrushes was generally positive.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.2
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• pp.238-244
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• 2003

With the purpose of evaluating the effect of ailing amount of pit and assure sealants on the microleakage, 6 groups of specimens with different filling amount, filling materials and surface pretreatment were investigated. Sixty permanent third molars were divided into three groups. The occlusal surface of each tooth was divided into two parts; the filing width of one part was below 1mm (group1, 3, 5), and in the other part more than 2mm (group 2, 4, 6) Group 1 and 2: Helioseal F was applied directly to etched enamel; Group 3 and 4: Helioseal F was applied to etched and scotchbond Multi-purpose plus pre-treated enamel; Group 5 and 6: Tetric Flow was applied. After 500 times thermocycling and dye infiltration, we evaulated the microleakage. The results were as follows; 1. The mean microleakage score at each width were increased in the following order;group 5<3<1, and group 6<4<2. 2. In comparing the groups with same material and surface pretreatment but with different filling width (group 1 versus 2, 3 versus 4, 5 versus 6), the microleakage scores were significantly different. 3 The microleage was affected by filling amount of pit and assure sealants than Oiling materials and dentin bonding agent pretreatment.