• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2001년도 추계학술대회 및 정기총회
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• pp.81-81
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• 2001

The photoinducible DNA cleaving activities of bromofluoroacetophenones as a novel photonuclease were investigated. The photolytic behavior and DNA cleaving acitivity of fluorine derivative were compared with those of non-fluorine substituted compound, 4'-bromoacetophenones. Although the DNA cleaving activities of fluorine analogs were similar with those of 4'-bromoacetophenones, ο-bromo-$\rho$-fluoro derivatives gave the better DNA cleaving activities than $\rho$-bromo-ο-fluoro derivatives did.

• 한국치위생학회지
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• 제16권1호
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• pp.147-153
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• 2016

Objectives: The purpose of the study is to investigate the relationship between fluorine concentration within finger nails and the level of dentifrice in dental hygiene students and non-health majoring students. Methods: A self-reported questionnaire was completed by seventy female college students living in Daegu and Gyeongbuk that are not supplied with fluoridation from May to June, 2014. Informed consent was approved by institutional review board (IRB). The questionnaire consisted of general characteristics of the subjects (11 items) and oral health behavior including number of toothbrushing, duration of toothbrushing, number of mouth rinsing, and amount of dentifrice. A dentist and a dental hygienist examined directly the subjects by the guideline of World Health Organization (WHO). The oral examination included decayed tooth, healthy tooth, and filled tooth. The nail samples were obtained from seventy female students. Results: Comparing the dental hygiene students and non-health majoring students, 62.5% of dental hygiene students used approximately 1300mg of dentifrice and 55.2% of non-health majoring students used 1800mg or more of dentifrice. The non-health majoring students used more dentifrice (p<0.01). The fluorine concentration within nails was $1.9905{\mu}l/g$ in dental hygiene students and $3.2149{\mu}l/g$ in non-health majoring students. The fluorine concentration within nails in the dental hygiene students was significantly lower(p<0.01). Conclusions: The accumulation of fluoride in human body is not fully caused by dentifrice. However, The accumulation may occur due to toothbrushing so that it is necessary to educate the students about the right use of the dentifrice.

• Bulletin of the Korean Chemical Society
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• 제26권3호
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• pp.393-398
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• 2005

The stability constants for the diaza-18-crown-6 ethers 2-6 and alkali metal cations ($Na^+,\;K^+,\;Rb^+\;and\;Cs^+$) were determined using potentiometry in 95% methanol. For each metal ion the stability constants of the partiallyfluorinated ligands 3-6 were larger than that of the non-fluorinated ligand 2, which might reflect an interaction between fluorine atoms and alkali metal cations. The stability constant of the ligand 4 was larger than that of the ligand 5 for each metal cation tested. This finding was also supported by the results of cation-induced chemical shifts in $^1H-,\;^{19}F$-NMR and extraction experiment. The potentiometry and NMR results as well as the X-ray crystal structures revealed that the position and number of fluorine atoms in the benzyl side arms was crucial for the enhanced interaction between a ligand and an alkali metal.

• Environmental Engineering Research
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• 제24권4호
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• pp.654-661
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• 2019

This study assessed the stabilization of fluorine (F)-contaminated soil using calcium hydroxide (Ca(OH)₂) and the consequent changes in human health risk. The bioavailable F decreased to 3.5%, (i.e., 57.9 ± 1.27 mg/kg in 6% Ca(OH)₂-treated soil sample) from 43.0%, (i.e., 711 ± 23.4 mg/kg in control soil sample). This resulted from the conversion of water-soluble F to stable calcium fluoride, which was confirmed by XRD spectrometry. Soil ingestion, inhalation of fugitive dust from soil, and water ingestion were selected as exposure pathways for human health risk assessment. Non-carcinogenic risks of F in soils reduced to less than 1.0 after stabilization, ranging from 4.2 to 0.34 for child and from 3.0 to 0.25 for adult. Contaminated water ingestion owing to the leaching of F from soil to groundwater was considered as a major exposure pathway. The risks through soil ingestion and inhalation of fugitive dust from soil were insignificant both before and after stabilization, although F concentration exceeded the Korean soil regulatory level before stabilization. Our data suggested that substantial risk to human health owing to various potential exposure pathways could be addressed by managing F present in soil.

• 한국염색가공학회지
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• 제29권4호
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• pp.195-201
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• 2017

To study the effect of oxyfluorination on water dispersion of phthalocyanine blue(C.I. pigment blue 15:3), the pigment was oxyfluorinated using various oxygen to fluorine ratio of the reactant gas. After the oxyfluorination of the phthalocyanine blue pigment, no significant change in FT-IR spectra was observed, whereas XPS spectra showed the introduction of oxygen and fluorine containing functional groups. This suggests that the oxyfluorination of the pigment only occurred on the surface of the pigment particle and resulted in no significant change in UV-Vis spectra of the pigment. However, the oxyflurinated pigments showed improved water dispersion, compared to the non-treated pigment. Especially, when the oxygen to fluorine ratio was 47:3, the water dispersion of the oxyfluorinated pigments significantly increased, compared to the non-treated pigments. This suggests that the oxyfluorination of the phthalocyanine blue pigment has a potential to be used as a water dispersion improving method.

• 콘크리트학회논문집
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• 제18권4호
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• pp.553-558
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• 2006

본 연구에서는 배합강도 30MPa로 설계된 25-30-18 규격의 콘크리트 배합에 불소화합물 및 실리카로 구성된 불소-실리카 복합형 균열저감제(FS)를 시멘트 중량을 기준으로 0.5% 간격으로 2.0%까지 첨가한 후 슬럼프 경시 변화, 공기량 경시 변화 및 블리딩 등의 굳지 않은 콘크리트의 재료특성을 평가하였다. 또한, 콘크리트 수화온도 변화에 미치는 영향과 소성수축 및 건조수축의 저항성에 미치는 효과를 파악하였다. FS가 첨가된 콘크리트의 재료특성에서 슬럼프 및 공기량 경시 변화는 무첨가 콘크리트에 비해 큰 차이가 없었으나 블리딩과 수화온도는 저감되는 것으로 나타났다. 특히, 경화 전 후 소성수축 및 건조수축에 기인된 콘크리트의 수축균열 저항성이 FS를 $1.0{\sim}1.5%$의 첨가함으로써 크게 저감됨을 알 수 있었다.

• 유기물자원화
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• 제31권2호
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• pp.5-18
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• 2023

국내 불소계 화학물질의 배출현황 조사결과 Hydrogen fluoride(91%)와 Perfluorocarbons(5%) 등 13종의 물질이 사업장을 통해 배출되었고, 지역별로는 경북, 경기, 충청권 지역에서 약 98%, 업종별로는 전자부품, 화학물질, 비금속 광물제품 제조업 관련 3개 분야에서 약 98%를 배출하였다. 주요 수계에서 나타나는 PFOS·PFOA의 검출 현황은 불소계 화학물질 배출량이 많은 낙동강 수계, 금강 수계, 안성천 하구언 지점에서 지속 검출되었으며, 4개의 PFOS 지점과 2개의 PFOA 지점은 2021년 처음으로 검출되었다. 반도체와 디스플레이 관련 업종이 많은 수계 지역에서 PFOS 및 PFOA가 비교적 높은 농도로 지속 검출되었다.

• 한국초전도ㆍ저온공학회논문지
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• 제2권1호
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• pp.1-6
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• 2000

The effects of partial substitution of fluorine on physical properties were studied in Ag-sheathes tapes of $Tl_{0.8}Pb_{0.2}Sr_{1.8}Ba_{0.2} Ca_{2.2}Cu_3O_yF_x (0{\leq}x{\leq}1)$ nominal compositions. The tapes were prepared using the powder-in-tube method incorporating an in-situ reaction method. $CuF_2$ was used as a source of F. It was found that F-doping in Tl-1223 system resulted in a decrease in formation temperatire of Tl-1223 phase. and thus significantly deteriorated their superconducting properties. Such disadvantages seem to originate by the fromation of non-beneficial phases such as SrF2 in the early stage of the powder preparation process.

• 한국응용과학기술학회지
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• 제35권4호
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• pp.1379-1385
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• 2018

The hand held voltammetry systems searched diabetic assay using glucose sensor of fluorine nafion doped carbon nanotube electrode (FCNE). An inexpensive graphite carbon pencil was used as an Ag/AgCl reference and Pt counter electrode. Upon combining and using three electrode systems, optimum square wave (SW) stripping results were attained to 1.0-9.0 ug/L with 8 points. Statistic RSD precision was of 6.02 % with n=15 in 0.1 mg/L glucose. After a total of 200 second accumulation times, analytical detection limit of 0.8 ug/L was obtained. This developed technique was applied to urine samples from diabetic patients urine for fluid analysis, it was determined that the sensor can be used with a diagnostics in the ex vivo of live cells and non treated biological fluid.

• Korean Chemical Engineering Research
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• 제59권4호
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• pp.508-513
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• 2021

고분자전해질 연료전지(PEMFC)의 내구성을 향상시키기 위해서는 필수적으로 고분자막의 내구성이 향상되어야한다. 고분자막의 내구성을 향상시키기 위해서 e-PTFE 지지체와 라디칼 제거제(Radical Scavenger)가 첨가된다. 본 연구에서는 e-PTFE 지지체가 들어간 강화막(Reinforced Membrane)과 비강화막(Non-reinforced Membrane)의 화학적 내구성을 Fenton 반응에 의해 비교하고자 하였다. 라디칼 제거제가 첨가되지 않은 고분자막의 Fenton 실험에서는 작게 절단한 시편의 단면을 통한 과산화수소 용액과 철이온의 흡수율이 강화막에서 더 높아 불소유출농도가 더 높게 나타났다. 라디칼 제거제의 종류와 첨가량에 따라 강화막의 불소유출농도가 3배 이상의 큰 차이가 발생해서 라디칼 제거제의 영향이 지지체의 영향보다 강한 것을 알 수 있었다.