• 방사선산업학회지
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• 제10권4호
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• pp.181-187
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• 2016

Selective ${\beta}_1$-agonist and antagonists are used for the treatment of cardiac diseases including congestive heart failure, angina pectoris and arrhythmia. Selective ${\beta}_1$-antagonists including nebivolol have high binding affinity on ${\beta}_1$-adrenergic receptor, not ${\beta}_2$-receptor mainly expressed in smooth muscle. Nebivolol is one of most selective ${\beta}_1$-blockers in clinically used ${\beta}_1$-blockers including atenolol and bisoprolol. We tried to develop clinically useful cardiac PET tracers using a selective ${\beta}_1$-blocker. Nebivolol is $C_2$-symmetric and has two chromane moiety with a secondary amino alcohol and aromatic fluorine. We adopted the general synthetic strategy using epoxide ring opening reaction. Unlike formal synthesis of nebivolol, we prepared two chromane building blocks with fluorine and iodine which was transformed to diaryliodonium salt for labelling of $^{18}F$. Two epoxide building blocks were readily prepared from commercially available chromene carboxylic acids (1, 8). Then, the amino alcohol building block (15) was prepared by ammonolysis of epoxide (14) followed by coupling reaction with the other building block, epoxide (7). Diaryliodonium salt, a precursor for $^{18}F$-aromatic substitution, was synthesized in moderate yield which was readily subjected to $^{18}F$-aromatic substitution to give $^{18}F$-labelled nebivolol.

• 대한방사성의약품학회지
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• 제3권2호
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• pp.122-128
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• 2017

In the 2000s, there has been a significant advance on carbon-fluorine (C-F) bond formation reactions via transition metal mediated or catalyzed methods. Of course, for the past 10 years, transition metal catalysis improves C-F bond formation in terms of practicality and even can be applied to C-18F bond formation reaction. In this mini-review, we summarize various transition metal mediated or catalyzed fluorination reactions, which were developed in the mid-2000s.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.683-686
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• 2005

This paper is related to investigate adding effect of fluorine-silicate hybrid type crack controlling agent(FS) on initial behavior, dynamic properties, adibatic hydration temp, and plastic crack behavior of concrete(Specification : 25-30-18). It is appeared that adding of FS contributed to strength elevation, lowering of hydration temperature as well as plastic crack reduction without disturbance of initial behaviors of concrete such as slump, air content and setting.

• 한국세라믹학회지
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• 제47권6호
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• pp.540-545
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• 2010

In this study, we have investigated new plasma resistant materials with less usage of rare-earth oxides than $Y_2O_3$ which is currently used in the semiconductor industry. We observed the stability ranges of $(Gd{\cdot}Y)_3Al_5O_{12}$ and $(La{\cdot}Y)Al_{11}O_{18}$ ternary systems, and measured their etch rates under typical fluorine plasma. $(Gd{\cdot}Y)_3Al_5O_{12}$ system showed an extensive solid solution up to 80 mol% gadolinium, but $(La{\cdot}Y)Al_{11}O_{18}$ showed a negligible substitution between rare-earth ions, which can be explained by the differences between the ionic radii. The etch rates depended on the total amount of rare-earth oxides but not on the substitution of the rare-earth ions. When the specimen was examined using XPS after the exposure to fluorine plasma, the strong surface fluorination was observed with a shift of the binding energy to higher energy.

• 대한화학회지
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• 제13권1호
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• pp.68-74
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• 1969

${\alpha},{\beta$}-dichloro-${\beta$}-phenyl propionate, Ethyl ${\alpha},{\beta$}-dibromo-${\beta$}-phenyl propionate, Etyyl ${\alpha},{\beta$}-dichloro-${\beta$}-(p-chlorophenyl)propionate, 및 dibromo-styrene 等의 化合物을 各種溶媒(dimethly formamide, diethylene glycol, 및 diethylene glyco monomethyl ether 等) 存在下에서 弗化反應을 시켜 보았으며 放射性弗素-18을 追跡子로 使用하여서 위의 化合物들의 弗化카리에 對한 反應度를 檢査하여 보았다. 一般的으로 弗化反應 生成物은 모노弗化物과 脫할로겐된 二重結合物을 生成하였다. diethylglycol 存在下에서 高溫反應시킨 條件下에서는 二重結合生成物이 많았고 diethylene glyco-monoethyl ether 存在下에서 低溫反應시킨 條件下에서는 弗化物이 多量生成하였다. 모노弗化物의 合成方式 및 確認方法에 關하여 說明하였으며 本反應의 合成上의 用途($F^{18}$ 標識化合物包含)에 言及하였다.

• 콘크리트학회논문집
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• 제18권5호
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• pp.631-637
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• 2006

본 연구에서는 배합강도 24MPa로 설계된 25-24-18 규격의 콘크리트 배합에 불소-실리카 복합형 균열저감제(FS)를 시멘트 중량을 기준으로 0.5% 간격으로 2.0%까지 혼입하고, 유동성상 및 경화성상 등의 기초물성을 평가하였다. 기초물성 결과로부터 콘크리트의 수축균열 및 투기성 평가를 위한 FS의 적정 첨가율로서 0.5%를 도출하였으며, 무첨가 콘크리트와 수축균열 및 투기성 평가를 위한 모의부재 시험을 실시하였다, 수축균열에서 FS를 0.5% 첨가한 콘크리트의 균열개수는 50%, 균열길이 및 균열면적은 각각 69.7%, 74.4% 감소되었다. 콘크리트의 투기성을 측정한 결과, FS를 첨가한 콘크리트가 투수계수는 67%, 침투깊이는 약 40% 감소하였다. 따라서 FS 첨가에 의해 콘크리트의 기초물성 저해 없이 콘크리트의 수축균열의 저감과 투기성이 향상되는 효과를 확인할 수 있었다.

• 핵의학기술
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• 제13권3호
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• pp.147-151
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• 2009

Purpose: 2-[$^{18}F$]Fluoro-2-deoxy-D-glucose ([$^{18}F$]FDG) particularly plays as a important role in Positron Emission Tomography (PET) imaging in nuclear medicine. Domestic [$^{18}F$]FDG auto synthesizers are installed in Seoul National University Bundang Hospital (SNUBH) at June 2008, these modules were known that it's synthetic yields were guaranteed in average $45{\pm}5%$ so far. To improve yields and convenience of domestic [$^{18}F$]FDG auto synthesizer, numerous trials in reaction time, base concentration, pressure and temperature were performed to increase [$^{18}F$]FDG yields. Materials and Methods: Several synthetic factors (temperature, time and pressure) and shortcoming were corrected based on many evaporation test. Syringe dispensing of tetra-butylammonium bicarbonate (TBAB) was replaced with micro pipette to prepare tetrabutyl ammonium fluoride salt ([$^{18}F$]TBAF). Troublesome refill of liquid nitrogen every 2 hours which was used to protect vacuum system was changed to charcoal cartridge, base guard filter. To monitor the volume of delivered $[^{18}O]OH_2$ from cyclotron by surveillance camera, we set up the volumetric vial on the cover of the module. In addition to, the recovery vial was added in [$^{18}F$]FDG production system to recover [$^{18}F$]FDG loss due to the leak of valve ($V_{13,14}$) in [$^{18}F$]FDG purification process. Results: When we used micro pipette for adding TBAB ($30\;{\mu}L$ in 12% $H_2O$ in acetonitrile), this quantitative dispensation has enabled to improve $5.5{\pm}1.7%$ residual fluorine-18 activity in fluorine separation cartridge compared to syringe adding. Besides, the synthetic yields of [$^{18}F$]FDG has increased $58{\pm}2.6%$ (n=19), $58{\pm}2.9%$ (n=14), $60%{\pm}2.5%$ (n=17) for 3 months. The life cycle of charcoal cartridge and base vacuum was 3 months prior to filling liquid nitrogen every 2 hours and additional side separator can prevent pump corrosion by organic solvent. After setting of volumetric indicator vial, the operator can easily monitor the total volume of irradiated $[^{18}O]OH_2$ from cyclotron. The recovery vial can be used for the stabilizer when an irregular [$^{18}F$]FDG loss was generated by the leak of valves ($V_{13,14}$). Conclusions: We has optimized appropriate synthetic conditions (temperature, time, pressure) in domestic [$^{18}F$]FDG auto synthesizer. In addition to, the remodeling with several accessories improve yields of domestic [$^{18}F$]FDG auto synthesizer with reliable reproducibility.

• 지질공학
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• 제18권1호
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• pp.103-115
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• 2008

이 연구의 목적은 경남 북서부 화강암 분포지역 지하수의 지구화학적 특징 및 불소의 원인을 물-암석반응으로 이해하는 데 있다. 이를 위하여 지하수의 수질과 모암인 화강암의 주요 성분간의 부화경향성을 검토하였으며, 변질된 암석내 광물의 미세조직을 전자현미경으로 관찰하고 화학성분을 분석함으로써 물-암석반응에 따른 지하수내 불소의 용존 원인을 해석하였다. 불소함량과 경도를 비교한 결과 이들 간에는 뚜렷한 상관성은 나타나지 않는다. 그러나 불소함량과 pH는 대체로 서로 비례하는 경향을 보이며, 공의 심도가 깊어질수록 불소함량도 증가한다. 흑운모의 변질작용은 벽개를 따라 일어나거나, 결정의 가장자리 부분에서 가장 우세하게 일어난다. 물-암석반응에 의하여 흑운모가 쉽게 변질되므로 본 연구지역의 지하수내 불소의 주공급원이 될 가능성이 가장 높다.

• 한국재료학회지
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• 제27권7호
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• pp.392-397
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• 2017

Fluorine-doped tin oxide (FTO) coated NiCrAl alloy foam is fabricated using ultrasonic spray pyrolysis deposition (USPD). To confirm the influence of the FTO layer on the NiCrAl alloy foam, we investigated the structural, chemical, and morphological properties and chemical resistance by using USPD to adjust the FTO coating time (12, 18, and 24 min). As a result, when an FTO layer was coated for 24 min on NiCrAl alloy foam, it was found to have an enhanced chemical resistance compared to those of the other samples. This improvement in the chemical resistance of using USPD NiAlCr alloy foam can be the result of the existence of an FTO layer, which can act as a protection layer between the NiAlCr alloy foam and the electrolyte and also the result of the increased thickness of the FTO layer, which enhances the diffusion length of the metal ion.

• 대한방사성의약품학회지
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• 제2권2호
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• pp.73-83
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• 2016

Imaging hypoxia using positron emission tomography (PET) is of great importance for cancer therapy. [$^{18}F$] Fluoromisonidazole (FMISO) was the first PET agent used for imaging tumor hypoxia. Various radiolabeled nitroimidazole derivatives such as [$^{18}F$]fluoroerythronitroimidazole (FETNIM), [$^{18}F$]1-${\alpha}$-D-(2-deoxy-2-fluoroarabinofuranosyl)-2-nitroimidazole(FAZA), 2-(2-nitroimidazol-1-yl)-N-(3,3,3-[18F]-trifluoropropyl)acetamide ([$^{18}F$]EF-3), [$^{18}F$]2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl) acetamide (EF-5), 3-[$^{18}F$]fluoro-2-(4-((2-nitro-1H-imidazol-1-yl)methyl)-1H-1,2,3,-triazol-1-yl)-propan-1-ol ([$^{18}F$]HX-4), and [$^{18}F$]fluoroetanidazole (FETA) were developed successively. However, these imaging agents still produce PET images with limited resolution; the lower blood flow in hypoxic tumors compared to normoxic tumors results in low uptake of the agents in hypoxic tumors. Thus, the development of better imaging agents is necessary.