• 대한소아치과학회지
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• 제25권3호
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• pp.539-544
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• 1998

저자는 열성형재료와 진공성형기를 이용하여 소아치과 임상에서 사용되는 수 종의 장치를 제작하였다. 전공성형기의 구입에 따른 경제적인 부담은 있으나, 기존의 제작법에 비해 제작이 간편하여 시간이 단축될 뿐 아니라 plate 의 두께가 균일하므로 finishing이 거의 필요하지 않으며 더욱 심미적인 장치를 제작할 수 있다. 또한 조직과 접촉하는 부위는 soft한 열성형재료를 사용하여 치아 이동에 유리할 뿐 아니라, 기존의 resin에 비해 불쾌한 맛이 적다는 장점이 있다. Monomer가 없어 조직에 자극이 적고 mutagenous potential이 없으므로 생체 적합성이 뛰어나 조직의 적응이 용이하다. 복잡하거나 특수한 기능 및 견고성이 필요한 악기능교정 장치 등에서는 그 사용이 제한된다는 한계점이 있으나, 소아치과 임상에서 사용되는 대부분의 장치를 쉽고 간편하게 제작할 수 있어 앞으로 임상에서 널리 이용될 수 있을 것으로 생각된다.

• 보건교육건강증진학회지
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• 제25권1호
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• pp.71-81
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• 2008

Objectives: The purpose of this study was to evaluate the long term effects of school-based oral health program on the decrease of dental caries among elementary school children. Methods: The subjects of this study were total 283 students of one elementary school in Deagu, Korea. They had received school-based oral health programs more than one year since 2004. This school-based oral health program included regular oral examination, fluoride mouthrinsing, pit-and-fissure sealing, APF gel application, tooth brushing instruction and chewing the xylitol tablets. The subjects' oral health status were examined and calibrated by a dentist every year from 2004 to 2007. Results: The change of DMFT index were as follows: (1)The subjects who entered the school at 2004 - 0.32(2004), 0.25(2005), 0.25(2006) and 0.38(2007), (2)the subjects who entered the school at 2005 - 0.18(2005), 0.31(2006) and 0.32(2007), and (3)the subjects who entered the school at 2006 - 0.19(2006) and 0.27(2007). Conclusions: This study partially showed the effects of school-based oral health programs on the increments of dental caries. This programs should be expanded widely among elementary schools in Korea.

• 한국전기전자재료학회논문지
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• 제33권3호
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• pp.181-185
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• 2020

Hazardous and noxious substance (HNS) detection sensors were fabricated using multi-walled carbon nanotubes (MWCNTs) and various binder materials for ion batteries. To obtain uniformly printed films, the printing precision according to the substrate cleaning method was monitored, and the printing paste mixing ratio was investigated. Binders were prepared using styrene butadiene rubber + carboxymethyl cellulose (SBR+CMC), polyvinylidene fluoride + n-methyl-2-pyrrolidene (PVDF+NMP), and mixed with MWCNTs. The surface morphology of the printed films was examined using an optical microscope and a scanning electron microscope, and their electrical properties are investigated using an I-V sourcemeter. Finally, sensing properties of MWCNT printed films were measured according to changes in the concentration of the chemical under the various applied voltages. In conclusion, the MWCNT printed films made of (SBR+CMC) were found to be feasible for application to the detection of hazardous and noxious chemicals spilled in seawater.

• 한국산학기술학회논문지
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• 제14권1호
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• pp.109-115
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• 2013

이 연구는 대구광역시와 경상북도에 소재하는 각각 3곳의 노인복지관 및 노인대학의 65세 이상 노인 501명을 대상으로 구강보건진료 관리 항목이 자가인식구강상태에 미치는 영향력을 조사함으로써 효과적인 구강보건관리 방안을 모색하기 위해 연구를 실시하였다. 연령에 따른 구강보건진료 관리 항목의 선호도를 조사한 결과, 65~69세는 불소도포, 65~74세는 치석제거, 칫솔질 교습, 70~74세는 틀니 세정 및 관리, 75세 이상은 틀니 제작을 선호하였다. 구강보건진료 관리 항목이 노인의 자가인식구강상태에 미치는 영향력은 현 구강상태가 좋지 않고, 저작지장이 많으며, 구강건조가 있을수록 틀니 제작을 가장 선호하는 것으로 나타났다. 치아수가 적고, 틀니를 가지고 있을수록 틀니 세정 및 관리를 가장 선호하였으며, 흔들리는 치아가 있고, 치통이 자주 있을수록 발치를 가장 선호하는 것으로 나타났다. 연령과 구강상태에 따라 구강보건진료 관리 항목의 선호도에 차이가 있으므로 각 개인에게 맞는 구강보건관리를 적용해야 할 것이다.

• Smart Structures and Systems
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• 제6권5_6호
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• pp.641-659
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• 2010

Structural Health Monitoring (SHM) gradually becomes a technique for ensuring the health and safety of civil infrastructures and is also an important approach for the research of the damage accumulation and disaster evolving characteristics of civil infrastructures. It is attracting prodigious research interests and the active development interests of scientists and engineers because a great number of civil infrastructures are planned and built every year in mainland China. In a SHM system the sheer number of accompanying wires, fiber optic cables, and other physical transmission medium is usually prohibitive, particularly for such structures as offshore platforms and long-span structures. Fortunately, with recent advances in technologies in sensing, wireless communication, and micro electro mechanical systems (MEMS), wireless sensor technique has been developing rapidly and is being used gradually in the SHM of civil engineering structures. In this paper, some recent advances in the research, development, and implementation of wireless sensors for the SHM of civil infrastructures in mainland China, especially in Dalian University of Technology (DUT) and Harbin Institute of Technology (HIT), are introduced. Firstly, a kind of wireless digital acceleration sensors for structural global monitoring is designed and validated in an offshore structure model. Secondly, wireless inclination sensor systems based on Frequency-hopping techniques are developed and applied successfully to swing monitoring of large-scale hook structures. Thirdly, wireless acquisition systems integrating with different sensing materials, such as Polyvinylidene Fluoride(PVDF), strain gauge, piezoresistive stress/strain sensors fabricated by using the nickel powder-filled cement-based composite, are proposed for structural local monitoring, and validating the characteristics of the above materials. Finally, solutions to the key problem of finite energy for wireless sensors networks are discussed, with future works also being introduced, for example, the wireless sensor networks powered by corrosion signal for corrosion monitoring and rapid diagnosis for large structures.

• 한국치위생학회지
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• 제21권4호
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• pp.441-453
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• 2021

Objectives: This study identified problems and improvements in projects targeted to dental workers in a child-adolescent dental care service. Methods: The subjects were 40 dentists, 43 dental hygienists, and 51 others who participated in service in Seoul. A self-administered questionnaire was used to address the problems and improvements in the project. Descriptive statistics, chi-square test, and one-way analysis of variance were performed using SPSS 23.0. Results: Oral examination was performed by 99.2% of dentists, and some service items such as professional tooth cleaning, fluoride application, and scaling were performed by dental auxiliary personnel regardless of legal duties. The problem was that the subjects took a lot of time in providing services, and students or guardians participating in the project refused to receive preventive dental services. As regards improvements, the insurance fee was the highest (48.1%), followed by the provision of regular services (38.8%), and system improvement and administrative support (35.7%). Conclusions: To activate a child-adolescent dental care service, it is thought that continuous efforts such as providing financial support by the government, education to increase participants' understanding, and social consensus for the participation of service providers and beneficiaries are required.

• 구강회복응용과학지
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• 제38권1호
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• pp.52-59
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• 2022

고정성 교정치료 중 치아의 협면의 치경부 탈회가 종종 발생한다. 이번 증례보고에서는 교정치료 중 발생한 치아의 치경부 탈회를 직접 레진 비니어 수복을 통해 치료한 2가지 증례를 보고하고자 한다. 우식이 없는 초기 병변은 주기적인 불소도포, 식이조절, 구강위생 개선을 통해 재광화될 수 있으나 점차 진행됨에 따라 적절한 수복치료가 필요하며 병소 발생 후의 치료보다 예방에 중점을 두는 것이 더욱 바람직하다.

• 치위생과학회지
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• 제22권1호
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• pp.44-50
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• 2022

Background: This study compares and analyzes the degree of oral health information literacy by 25% for upper and lower grades to assess how differences in mothers' oral health information literacy affect infants' oral health behavior. Methods: The study surveyed 201 mothers with infants and children using a 36 question survey tool. Cross-analysis was conducted to determine the difference in oral health information literacy between the upper and the lower 25%. Results: Comparing 25% of the upper and lower grades of verbal oral health information literacy scores, the word with the most significant difference in the correct answer was resin. An item asking about the time to eat after fluoride varnish application showed the most significant difference in the correct answer on the functional oral health information literacy scale. Mothers' oral and functional oral health information literacy scores showed that verbal literacy was statistically significant for brushing guidance after children's meals, brushing guidance before children's bedtime, food intake restrictions before bedtime, and restrictions on consumption of cavity-inducing foods (p<0.05). Functional literacy was statistically significant in the post-brushing test of children and the correct brushing method map items (p<0.05). Conclusion: As a result of comparing and analyzing the upper and lower 25% of the mother's oral health information literacy, it was found that the mother's oral health information literacy affected the infant's oral health behavior. Therefore, systematic education is needed to raise literacy by grasping the level of oral health information literacy of mothers, and oral health education by level according to oral health information literacy should be developed.

• 한국음향학회지
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• 제25권4호
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• pp.164-171
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• 2006

임의의 등방성재료에 대한 종파, 횡파 및 누설표면파의 음속을 알면 해석적으로 그 재료의 탄성정수와 밀도를 산출할 수 있다. 종래, 그 음속들은 각각 다른 진동모드를 갖는 세 개의 초음파 트랜스듀서에 의해 측정되어져 왔다. 본 연구에서는 하나의 트랜스듀서에 의해 그 세 가지 파의 개략적인 음속을 동시에 측정하기위한 전극분할형 PVDF 직선집속 초음파 트랜스듀서를 새로이 제안하고, 설계, 제작하였다. 그리고 그것에 의한 각 파의 음속측정 방법을 확립한 후, 용융석영 등 몇몇 등방성재료에 적용하였다. 또한, 측정된 각 파의 음속을 이용하여 탄성 강성정수 및 밀도를 산출하고, 각 값들의 오차를 검토하였는데, 얻어진 값들은 문헌치와 비교적 잘 일치함을 알 수 있었다.

• Advances in materials Research
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• 제13권3호
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• pp.153-160
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• 2024

This study investigates the application of alternating current (AC) and direct current (DC) anodization techniques on stainless steel 304L (SS304L) in an ethylene glycol and ammonium fluoride (NH4F) electrolyte solution to produce a nano-porous oxide layer. With limited research on AC anodizing of stainless steel, this study focuses on comparing AC and DC anodization in terms of current density versus time response, phase analysis using X-ray diffraction (XRD), and corrosion rate determined by linear polarization. Both AC and DC anodization were performed for 60 minutes at 50 V in an electrolyte solution containing 0.5% NH4F and 3% H₂O in ethylene glycol. The results show that AC anodization exhibited higher current density compared to DC anodization. XRD analysis revealed the presence of ferrite (α-Fe) and austenite (γ-Fe) phases in the as-received specimen, while both AC and DC anodized specimens exhibited only the γ-Fe phase. The corrosion rate of the AC-anodized specimen was measured at 0.00083 mm/year, lower than the corrosion rate of the DC-anodized specimen at 0.00197 mm/year. These findings indicate that AC anodization on stainless steel offers advantages in terms of higher current density, phase transformation, and lower corrosion rate compared to DC anodization. These results highlight the need for further investigation and exploration of AC anodization as a promising technique for enhancing the electrochemical properties of stainless steel.