• 한국콘텐츠학회논문지
• /
• 제22권7호
• /
• pp.663-669
• /
• 2022

본 연구는 세치제에 함유되어지는 불소의 함유량이 1500ppm이하로 상향됨에 따라 시판되어지는 세치제의 불소 함유량도 향상되었다. 이에 따라 인체에 노출되어지는 불소의 양을 예측하고 이를 소비자에게 제공하여 안전한 세치제의 사용에 대한 대안을 제시하는데 목적이 있다. 본 연구는 2021년 3월부터 2주간 1300명을 대상으로 일반적 특성과 구강건강행위를 설문조사하였다. 조사한 결과를 ConsExpo Web 1.0.2. 노출평가하기 위한 입력변수로 사용하였다. 그 결과 불소가 1500ppm함유된 세치제를 사용할 경우남자는 External dose on day of exposure가 2.3×10-2 mg/kg/day, 여자의 경우 2.9×10-2 mg/kg/day, 2-3세 아동은 7.3×10-2 mg/kg/day로 추정되었다. 본 연구결과 시중에 유통되어지는 세치제의 불소함유량이 증가됨에 따라 소비자들의 안전한 사용을 위한 기준을 제시하는데 기초자료로 사용될 것이라 사료되어진다.

• 한국치위생학회지
• /
• 제10권1호
• /
• pp.93-106
• /
• 2010

Objectives : The study examined mothers' oral health knowledge and oral health management behavior to their children that affect directly children's oral health to prepare basic aiming at children. Methods : Therefore, a survey of 235 mothers in 10 kindergartens located in Seoul was conducted by self-administered questionnaires. Results : As to mothers' oral health knowledge, the correct-answer rate for questions about tooth-decay was highest, and the level of 'middle (5-7 points)' was the most common with 50.0%. Regarding oral health knowledge according to mothers' general characteristics, the higher academic background and family's monthly earnings were, the higher oral health knowledge was. It showed a statistically significant difference(p<.01). In terms of mothers' oral health management behavior to their children, 79.1% of mothers who had the visiting experience in the dentist's for caries prevention was highest. As to the number of brushing, the twice was highest with 51.2%, and regarding brushing time 2min was highest52.6%. Also, the rate of using the fluoride toothpaste was 68.4%, and the rate of mothers who helped their children's brushing was 83.3%. As to the oral health management behavior to their children by mothers' oral health knowledge, mothers with higher oral health knowledge used the fluoride toothpaste showing that there was a significant difference(p<.01). Also, mothers with higher oral health knowledge helped more children's brushing, so that there was a significant difference(p<.05). Regarding the oral health management behavior to their children according to mothers' visiting experience in the dentist's, mothers who visited the dentist's during the recent one year had higher visiting experience of dentist's for children's caries prevention(p<.01) and longer time of brushing by 3min(p<.05), and helped their children's brushing a lot. The findings showed a significant difference(p<.001). Conclusions : As the results above, as mothers' oral health knowledge and oral health management behaviors to their children affect closely children's oral health, more systematic, specific and active oral health programs should be provided to mothers.

• 한국치위생학회지
• /
• 제15권1호
• /
• pp.119-127
• /
• 2015

Objectives: The purpose of the study is to investigate the relationship between dental caries and oral health behaviors in middle and high school students by web-based survey of the ninth(2013) Korean youth risk behavior. Methods: The subjects were 75,149 students from 400 middle schools and 400 high schools. Finally, the survey participation rate was 96.4%(72,435 students from 799 schools) by complex sample design. The questionnaire consisted of general characteristics of the subjects, oral health behaviors, and oral health status. General characteristics included gender, types of schools, economic condition, and residential types. Oral health behaviors included subjective oral health condition, frequency of tooth brushing, tooth brushing after meal within recent 7 days, sealant within 12 months, fluoride application within 12 months, scaling within 12 months, and oral health education experience within 12 months. Oral health condition included dental caries incidence within 12 months. Results: Oral health behavior influenced on dental caries in the middle and high school students in Korea. This study showed the relationship between the sociodemographic characteristics, tooth brushing frequency, sealant experience, dental caries and halitosis experience, and scaling within 12 months. Scaling is the best prevention method for dental caries and halitosis in the students. Conclusions: The study showed the necessity for practical oral health education and the effect of fluoride application for dental caries prevention.

• 한국섬유공학회:학술대회논문집
• /
• 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
• /
• pp.7-8
• /
• 2003

Since PVDF/poly(1,4-butylene adipate) blend shows much lower LCST curve compared with PVDF/PMMA blend, the PVDF/PBA blend can be a good candidate for investigating the effect of the electric field on the phase separation and dissolution behavior of an electro-active polymer and electro-inactive polymer blend. (omitted)

• 한국안전학회지
• /
• 제30권1호
• /
• pp.14-20
• /
• 2015

A Large Eddy Simulation(LES) was performed for the prediction of unsteady dispersion behavior of hydrogen fluoride (HF). The HF leakage accident occurred at the Gumi fourth industrial complex was numerically investigated using the Fire Dynamics Simulator (FDS) based on the LES. The accident area was modeled three-dimensionally and time-varying boundary conditions for wind were adopted in the simulation for considering the realistic accident conditions. The Message Passing Interface (MPI) parallel computation technique was used to reduce the computational time. As a result, it was found that the present LES simulation could predict the unsteady dispersion features of HF near the accident area effectively. The dispersion behaviors of the leaked HF was much affected by the unsteady wind direction. The LES could predict the time variation of the HF concentration reasonably and give an useful information for the risk analysis while the prediction with the time-averaging concept of HF concentration had a limitation for the amount of HF concentration at specific location point. It was identified that the LES is very useful to predict the dispersion characteristics of hazardous chemicals.

• Macromolecular Research
• /
• 제17권10호
• /
• pp.757-762
• /
• 2009

The micro domain structures and crystallization behavior of the binary blends of poly(methyl methacrylate)-b-poly(pentafluorostyrene)-b-poly(methyl methacrylate) (PMMA-PPFS-PMMA) triblock copolymer with a low molecular weight poly(vinylidene fluoride) (PVDF) were investigated by small-angle X-ray scattering (SAXS), small-angle light scattering (SALS), transmission electron microscopy (TEM), optical microscopy, and differential scanning calorimetry (DSC). A symmetric, PMMA-PPFS-PMMA triblock copolymer with a PPFS weight fraction of 33% was blended with PVDF in N,N-dimethylacetamide (DMAc). In the wide range of PVDF concentration between 10.0 and 30.0 wt%, PVDF was completely incorporated within the PMMA micro domains of PMMA-PPFS-PMMA without further phase separation on a micrometer scale. The addition of PVDF altered the phase morphology of PMMA-PPFS-PMMA from well-defined lamellar to disordered. The crystallization of PVDF significantly disturbed the domain structure of PMMA-PPFS-PMMA in the blends, resulting in a poorly-ordered morphology. PVDF displayed unique crystallization behavior as a result of the space constraints imposed by the domain structure of PMMA-PPFS-PMMA. The pre-existing microdomain structures restricted the lamellar orientation and favored a random arrangement of lamellar crystallites.

• 폴리머
• /
• 제28권6호
• /
• pp.509-518
• /
• 2004

비대칭 블록 공중합체와 단일고분자로 구성된 블렌드의 미세 도메인 구조와 결정화 거동을 소각 X-선 산란, 광학 현미경 및 DSC를 사용하여 조사하였다. 본 연구에서는 폴리(메틸 메타크릴레이트) 블록의 무게 분률이 0.53인 폴리(메틸 메타크릴레이트)-폴리스티렌 이종 블록 공중합체 (PMMA-b-PS)를 저분자량 폴리(비닐리덴 플루오라이드) (PVDF)와 혼합하였다. PVDF 함량 증가에 따라 블렌드 미세구조가 라멜라에서 실린더 구조로 전이하였으며, PVDF의 결정화는 결정화 이전에 형성된 미세구조의 배열을 교란시켜 질서도가 낮은 형태를 야기시켰다. 또한, PVDF 결정화 거동은 PMMA 블록과의 혼화성 및 미세 도메인에 의해 부가되는 공간적 제한에 큰 영향을 받았다.

• 한국표면공학회지
• /
• 제49권3호
• /
• pp.280-285
• /
• 2016

In this study, we investigated the influences of potassium fluoride(KF) addition on the surface characteristics of plasma electrolytic oxidation(PEO) coating produced on Al alloy. The PEO of marine grade Al alloy(5083 grade) was conducted in KOH 1g/L solution adding different concentrations of KF(0, 1 and 2 g/L) under a galvanostatic regime. With KF addition, unusual behavior was observed on the voltage-time characteristic curves, which can be characterized by the following process: (i) initial rapid increase in voltage (ii) a short plateau after 1st breakdown (iii) gradual increase in voltage (iv) intermittent fluctuation of voltage after 2nd breakdown. The SEM observation revealed irregular surface morphology with KF addition, as compared with one formed without KF addition, which had a reticulate structure. The XRD analysis detected the formation of aluminium hydroxide fluoride hydrate($H_{4.76}Al_2F_{3.24}O_{3.76}$) on surface grown by PEO process with KF. Particularly, at very early stage of the process (~ 120 s), thin film was formed having nanoporous structure, and F element was confirmed on surface by EDS analysis. The thickness and surface roughness of the coating increased with increasing KF concentration. As a result, KF addition was found to be less beneficial influences on PEO of marine grade Al alloy, and therefore needs further research to improve its capability.

• 공업화학
• /
• 제17권5호
• /
• pp.483-489
• /
• 2006

희토류 화합물인 $La_{2}O_{3}$ 및 $CeO_{2}$ 시약과 이들을 함유하는 희토류 광석을 이용하여 제철 폐수 중의 불소 및 유해 중금속 제거에 대하여 연구하였다. 용액 중 불소에 대한 희토류 원소의 제거 반응기구는 $La^{3+}$ 및 $Ce^{4+}$ 등의 양이온이 불소 이온과 불용성 화합물을 형성하는 것으로 알려져 있다. 기존의 불소 제거에 사용되고 있는 소석회와 비교한 결과 $La_{2}O_{3}$ 및 $CeO_{2}$ 의 불소제거 효율이 높았다. HF 용액에서의 제거 효율은 $CeO_{2}$ 광석 < $CeO_{2}$ 시약 < $Ca(OH)_{2}$ < $La_{2}O_{3}$ 광석 < $La_{2}O_{3}$ 시약의 순서였고, 제철 폐수에서는 $Ca(OH)_{2}$ < $CeO_{2}$ 광석 < $CeO_{2}$ 시약 < $La_{2}O_{3}$ 광석 < $La_{2}O_{3}$ 시약의 순서였다(pH의 영향은 소석회인 경우 pH가 증가할수록 불소제거율이 감소하였다. 세륨화합물과 란탄화합물인 경우는 pH 증가에도 불구하고 불소제거 효율이 증가하는 경향을 보였으나 방류 시 수질조건과 불소제거율을 함께 고려할 때 용액의 적정 pH는 7이 적당하다고 판단된다). 망간제거의 경우, pH 7 이하에서는 소석회가 희토류 화합물보다 우수한 망간제거율을 보였고 pH 10에서는 모든 처리제에 대해서 거의 완벽한 제거특성을 보였다. 총크롬 제거의 경우는 산성 조건에서는 란탄화합물이 가장 높은 불소 제거율을 보였으며 pH 7이상에서는 모든 처리제가 좋은 효율을 보였다.

• 한국치위생학회지
• /
• 제15권6호
• /
• pp.999-1007
• /
• 2015

Objectives: The objective of the study is to investigate oral health behavior and oral health education experience in Korean adolescents from the ninth(2013) web-based survey of Korean youth risk behavior. Methods: The subjects were 72,435 students through the ninth 2013 web-based survey of Korean youth risk behavior conducted by the Ministry of Education, Science, and Technology, the Ministry of Health and Welfare, and the Korea Centers for Disease Control. The questionnaire consisted of socio-demographical characteristics of the subjects, oral health behavior, and oral health education experience. Data were analyzed by SPSS 18.0 program. Results: Oral health education had much influence on tooth brushing after lunch, oral cavity disease prevention, sealants, fluoride application, scaling experience, and consumption of vegetables, milk, carbonated soft drinks, noodles, and snacks. The oral health education had a great impact on those who took good oral health behavior into action. Conclusions: It is very important and necessary to develop the continuing effective oral health education program for the adolescents and make them tale into action.