• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.1
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• pp.17-26
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• 2016

The use of a rubber dam is a useful technique for protecting patients and operators, producing good results when treating children and adolescent patients. Despite its many advantages, some children and adolescent patients have negative feelings and sometimes express its discomfort. The purpose of this study was to evaluate the patients' preferences for rubber dam use and the associated factors that may affect it. A survey was conducted targeting patients aged 4-18 years old who visited the pediatric dental clinic, the restorative dental clinic, or the student treatment dental clinic of ${\bigcirc}{\bigcirc}$ University Dental Hospital, and were treated using a rubber dam without sedation. We collected questionnaires through electronic medical records. Most children and adolescent patients showed positive attitudes towards using rubber dams. The group with a short treatment time and the group with past knowledge or experience of rubber dam use showed more positive attitudes towards rubber dams (p < 0.05), while no significant difference was found among factors such as gender, age, procedure, anesthetics, treatment site, and operator (p > 0.05).

• The Journal of the Korean dental association
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• v.53 no.11
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• pp.795-803
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• 2015

A questionnaire-based survey was done to evaluate the patients' perception on the use of Rubber Dam (RD) for the tooth isolation during dental treatment. Total 106 questionnaire were gathered and the data were analyzed according to the patients' gender, age, previous experience of RD. The 96% of total patients reported no experience of RD in their previous treatment. The first advantage of RD was selected as the protection of irrigant and medication into the oral cavity and the disadvantage was selected as saliva gathering during treatment. 98% of patients want to use RD for the next treatment and 99% remarked that the RD is essential for the dental treatment. Based on the surveyed data, majority of the patients highly satisfied with the RD use and they want to use RD and may consider the use of RD for the selection of dental clinic.

• Journal of Urban Science
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• v.10 no.1
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• pp.39-48
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• 2021

In this study, to evaluate the characteristics of the pollution in the major inflow tributaries and major environmental facilities in the watershed of Ara waterway, An inflow flow rate measurement and water quality analysis were conducted during dry and rainy seasons. In addition, the flow rate measurement, water quality analysis, and pollutant load at each monitoring point were compared and evaluated. Influx of BOD5, T-P and T-N into the tributaries of the ARA waterway watershed, excluding the Gulpo river watershed, during dry season were only 0.007%, 0.005% and 0.004% respectively of the incoming loads in the entire ARA waterway basin. In addition, it was confirmed that the discharge pollutant loads during rainfall event was about 440 times more for BOD5, about 545 times on T-P, and about 23 times on T-N in comparison to the pollutant loads during the dry days. When the Gulhyeon rubber dam was deflated, the discharged pollutant load during a rainfall was higher than the estimated load at the G7 monitoring point because the deposited pollutants from the upstream riverbed flowed down. Therefore, during a rainy season, it is necessary to manage the influx of high-load water pollutants from the overflow and deflation of the Gulhyun rubber dam as well as to find a strategy to reduce the pollutant loads in the Gulpo river watershed.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09a
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• pp.493-493
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• 2005

• Proceedings of the Korea Water Resources Association Conference
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• 2003.05b
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• pp.799-802
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• 2003

• KCID journal
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• v.6 no.1
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• pp.74-80
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• 1999

• Elastomers and Composites
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• v.37 no.3
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• pp.183-191
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• 2002

Rubber materials with excellent damping property are widely applied for vibration isolators. The dynamic characteristics of the rubber materials for vibration isolators were investigated. Dynamic tests for rubber materials with five different hardness were performed. In dynamic tests for test specimen, non-resonance method was used to obtain the dynamic storage modulus and loss factor. Moreover, the effect of dynamic vibration frequency, strain amplitude and temperature were investigated. As results, the storage modulus and loss factor generally increase when the hardness and frequency increase, and the glass transition temperature is $-50^{\circ}C$ by a large change in modulus and loss factor.

• Elastomers and Composites
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• v.53 no.4
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• pp.202-206
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• 2018

Five solution styrene butadiene rubber/neodymium butadiene rubber (SSBR/NdBR) composites were manufactured using different ratios of SSBR and NdBR. In this study, the composites were reinforced with NdBR and silica to confirm the physical properties of SSBR used for treads of automobile tires and the dispersibility with silica. The morphologies of the rubber composites were observed using field-emission scanning electron microscopy (FE-SEM). The crosslinking behaviors of the composites were tested using a rubber process analyzer (RPA), and the abrasion resistances were tested using a National Bureau of Standards (NBS) abrasion tester. The hardness values, tensile strengths, and cold resistances of the composites were also tested according to ASTM standards. Increased NdBR content yielded composites with excellent crosslinking properties, abrasion resistances, hardnesses, tensile strengths, and cold resistances. The crosslinking point increased due to the double bond in NdBR, thereby increasing the degree of crosslinking in the composites. The NdBR-reinforced composites exhibited excellent abrasion resistances, which is explained as follows. In SSBR, a breakage is permanent because a resonance structure between styrene and SSBR forms when the molecular backbone is broken during the abrasion process. However, NdBR forms an additional crosslink due to the breakdown of the molecular backbone and high reactivity of the radicals produced. In addition, the low glass transition temperature (Tg) of NdBR provided the rubber composites with excellent cold resistances.

• Journal of the korean academy of Pediatric Dentistry
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• v.40 no.2
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• pp.98-105
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• 2013

The purpose of this study was to investigate the mesiodistal widths at the cervical level of primary second molars in Korean children, and to compare them with commercial rubber dam clamps commonly used in pediatric dentistry. Dental casts of 115 primary and mixed dentition children were studied. Cervical mesiodistal width (C-MD) was measured at the clinical cervical level of each primary second molar from buccal and lingual sides using a digital caliper (Absolute, Mitutoyo, Kawasaki, Japan). The data were compared with mesiodistal widths of rubber dam clamps #203/204, #10/11, and #205 (Dentech, Japan). C-MDs of primary mandibular second molars were larger than those of primary maxillary second molars, and C-MDs at buccal sides were larger than those of lingual sides. All C-MDs showed statistically significant discrepancies to corresponding widths on clamps (p < 0.05). However the amount of discrepancy was mild in maxillary teeth, while up to 1 mm of discrepancy was shown in mandibular teeth. In conclusion, C-MDs measured in this study imply a relatively fair fit of #10/#11 or #203/#204 clamps on primary maxillary second molars, while suggesting our need for a better clamp with proper size for primary mandibular second molars.

• Elastomers and Composites
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• v.51 no.2
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• pp.93-98
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• 2016

The composites of EVA/EPDM including aluminum trioxide (ATH) as a fire retardant were manufactured for the purpose of improving low temperature property and flame resistance in the rubbery materials. The ratio of EVA to EPDM didn't affect the flame resistance of the rubber composites. The addition of ATH resulted in increase of the flame resistance. In the evaluation of the cold resistance, the increasing EPDM content showed enhancement of cold resistance in the composites due to increasing low Tg EPDM. It was found out that tensile strengths of the composites showed a maximum value at 100 phr of ATH by reinforcing effect, but a minimum value at 200 phr of ATH owing to slippage between the flame retardant by the external stress. In the measurement of solvent resistance in tetrahydrofuran, the increasing ATH content yielded enhancement of solvent resistance by reducing swelling of the composite, and increasing EPDM content also resulted from increase of the solvent resistance by reduction of polarizability as well as increase of crosslink in the composites.