• Bulletin of the Korean Chemical Society
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• 제29권8호
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• pp.1464-1466
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• 2008

Tetrabutylammonium Fluorodichloroplumbate(II), N$(C_4H_9)_4$[$PbCl_2F$], TBAFDiCP and Tetrabutylammonium Fluorodiiodoplumbate(II), [$(C_4H_9)_4$N][$PbI_2F$], TBAFDiIP are the first examples of fluoroplumbate salts that have been prepared from the reaction of $(C_4H_9)_4$NF with $PbCl_2$ and $PbI_2$ respectively using either $CH_3CN$ solvent. These new compound characterized by elemental analysis, IR, UV/Visible, $^1H$ NMR, and $^{19}F$ NMR techniques.

• The Korean Journal of Physiology and Pharmacology
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• 제14권1호
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• pp.51-57
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• 2010

It was hypothesized that NaF induces calcium sensitization in $Ca^{2+}$-controlled solution in permeabilized rat mesenteric arteries. Rat mesenteric arteries were permeabilized with $\beta$-escin and subjected to tension measurement. NaF potentiated the concentration-response curves to $Ca^{2+}$ (decreased $EC_{50}$ and increased $E_{max}$). Cumulative addition of NaF (4.0, 8.0 and 16 mM) also increased vascular tension in $Ca^{2+}$-controlled solution at pCa 7.0 or pCa 6.5, but not at pCa 8.0. NaF-induced vasocontraction and $GTP{\gamma}S$-induced vasocontraction were not additive. NaF-induced vasocontraction at pCa 7.0 was inhibited by pretreatment with Rho kinase inhibitors H1152 or Y27632 but not with a MLCK inhibitor ML-7 or a PKC inhibitor Ro31-8220. NaF induces calcium sensitization in a $Ca^{2+}$ dependent manner in $\beta$-escin-permeabilized rat mesenteric arteries. These results suggest that NaF is an activator of the Rho kinase signaling pathway during vascular contraction.

• 한국세라믹학회지
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• 제43권1호
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• pp.48-54
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• 2006

Hydroxyapatite $(HAp,\;Ca_{10}(PO_4)_6(OH)_2)$/alumina composites were fabricated with the addition of fluorides, such as $MgF_2$ and $CaF_2$. In this study, the effect of fluorides on the inhibition of phase decomposition and the mechanical properties of HAp was investigated. Due to the higher solubility of F ion in HAp structure, $MgF_2$ additive was more effective compared to $CaF_2$ additive in the lowering decomposition temperature of HAp. Therefore, the dissociation tendency of HAp was fully inhibited below $1400^{\circ}C$. The mechanical properties of HAp composites with $MgF_2$ additive showed higher value (flexural strength: $\~170MPa$, Vickers hardness: $\~7\;GPa$, fracture toughness: $\~1.5\;MPam^{1/2}$) compared to $MgF_2-free$ composites. The linear thermal expansion coefficient of HAp composites with $MgF_2$ showed the value of $16.4\times10^{-6}/^{\circ}C\;at\;20\~400^{\circ}C $.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.127-130
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• 2002

In this study, development of a new LTCC material using a non-glassy system was attempted with respect to reducing the fabrication process steps and cost down. Lowering the sintering temperature can be achieved by liquid phase sintering. For LTCC application, the starting material must have quality factor as high as possible in microwave frequency range. And also, the material should have a low dielectric constant for enhancing the signal propagation speed. Regarding these factors, dielectric constants of various materials were estimated by the Clausius-Mosotti equation. Among them, CaWO$_4$ was tamed out the suitable LTCC material. CaWO$_4$ can be sintered up to 98% of full density at 1200$^{\circ}C$ for 3 hours. It's measured dielectric constant, quality factor, and temperature coefficient of resonant frequency were 10.15, 62880GHz, and -27.8ppm/$^{\circ}C$, respectively. In order to modify the dielectric properties and densification temperature, 0.5∼1.5 wt% LiF were added to CaWO$_4$. LiF addition reduced the sintering temperature/time down to 800$^{\circ}C$/10∼30min due to the reactive liquid phase sintering. Dielectric constant lowered from 10.15 to 9.38 and Q x fo increased up to 92000GHz with increasing LiF content.

• Corrosion Science and Technology
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• 제4권1호
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• pp.8-14
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• 2005

The corrosion behaviour of mild steel in phosphoric acid solution in the presence and absence of pollutants viz. Chloride, Fluoride and Sulfate ions at 302K-333K was studied using mass loss and potentiostatic polarization methods. The addition of chloride and sulfate ions inhibits the mild steel corrosion in phosphoric acid while fluoride ions stimulate it. The effect of temperature on the corrosion behaviour of mild steel indicated that inhibition of chloride and sulfate ions decreased with increasing temperature. The adsorption of these ions (Chloride and sulfate) on the mild steel surface in acid has been found to obey Langmuir adsorption isotherm. The values of activation energy (Ea) and free energy of adsorption ($\Delta$) indicated physical adsorption of these ions (chloride and sulfate) on the mild steel surface. The plot of $logW_{f}$ against time (days) at 302K gives a straight line, which suggested that it obeys first order kinetics and also calculate the rate constant k and half-life time $t_{1/2}$.

• Nuclear Engineering and Technology
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• 제50권3호
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• pp.488-493
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• 2018

The Firebrick Resistance-Heated Energy Storage (FIRES) concept developed by the Massachusetts Institute of Technology aims to enhance profitability of the nuclear power industry in the next decades. Studies carried out at Massachusetts Institute of Technology already provide estimates of the potential revenue from FIRES system when it is applied to industrial heat supply, the likely first application. Here, we investigate the possibility of operating a power plant (PP) with a fluoride-salt-cooled high-temperature reactor and a closed Brayton cycle. This variant offers features such as enhanced nuclear safety as well as flexibility in design of the PP but also radically changes the way of operating the PP. This exploratory study provides estimates of the revenue generated by FIRES in addition to the nominal revenue of the stand-alone fluoride-salt-cooled high-temperature reactor, which are useful for defining an initial design. The electricity price data is based on the day-ahead markets of Germany/Austria and the United States (Iowa). The proposed method derives from the equation of revenue introduced in this study and involves simple computations using MatLab to compute the estimates. Results show variable economic potential depending on the host grid but stress a high profitability in both regions.

• 센서학회지
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• 제27권6호
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• pp.407-413
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• 2018

Most sleep apnea patients exhibit severe snoring, and long-lasting sleep apnea may cause insomnia, hypertension, cardiovascular diseases, stroke, and other diseases. Although polysomnography is the typical sleep diagnostic method to accurately diagnose sleep apnea by measuring a variety of bio-signals that occur during sleep, it is inconvenient as the patient has to sleep with attached electrodes at the hospital for the diagnosis. In this study, a diagnostic pillow is designed to measure respiration, heart rate, and snoring during sleep, using only one polyvinylidene fluoride (PVDF) sensor. A PVDF sensor with piezoelectric properties was inserted into a specially made instrument to extract accurate signals regardless of the posture during sleep. Wavelet analysis was used to identify the extractability and frequency domain signals of respiration, heart rate, and snoring from the signals generated by the PVDF sensor. In particular, to separate the respiratory signal in the 0.2~0.5 Hz frequency region, wavelet analysis was performed after removing 1~2 Hz frequency components. In addition, signals for respiration, heart rate, and snoring were separated from the PVDF sensor signal through a Butterworth filter and median filter based on the information obtained from the wavelet analysis. Moreover, the possibility of measuring sleep apnea from these separated signals was confirmed. To verify the usefulness of this study, data obtained during sleeping was used.

• Journal of Pharmaceutical Investigation
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• 제31권1호
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• pp.27-35
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• 2001

To evaluate the site-specific permeation of aspalatone (acetylsalicylic acid maltol ester, AM) through gastrointestinal tract, the enzymatic degradation and permeation studies were carried out using gastric, duodenal and jejunal mucosae of rabbits. It was found that $15.2{\pm}11.4%$, $11.6{\pm}5.2$ and $0.8{\pm}0.6%$ of the donor dose of AM, salicylmaltol (SM) and aspirin (ASA) permeated through the upper gastric mucosa after 8 hr of permeation, respectively. After 8 hr of AM permeation, SM and ASA were measured to be $15.0{\pm}1.7$ and $2.6{\pm}0.8%$ of the dose in the donor solutions, respectively, and salicylic acid (SA) was not detected even after 6 hr, suggesting a very low gastric damage. For the gastric mucosa, the increase of donor dose from 100 to $1,000\;{\mu}g/ml$ increased the permeation flux dose-dependently (r=0.9905). For the duodenal and jejunal mucosae, however, AM was fully degraded into SM and SA due to the esterase activities within 30 min. AM and ASA were not detected in the receptor solution. This result indicates that AM is not a prodrug of ASA. Addition of potassium fluoride (0.5%) into the donor solution delayed the degradation of AM, but did not allow the permeation through duodenal mucosa even by the inhibition of esterase activity. The addition of $dimethyl-{\beta}-cyclodextrin$ and $2-hydroxypropyl-{\beta}-cyclodextrin$ (5%) into the donor solutions also did not show favorable effects on the permeation of AM through various mucosae. In comparison of permeation rates of AM and ASA through the upper gastric mucosa, the flux of ASA was 4.2 times faster than AM based on the molar concentration. ASA also was fully degraded in the donor solutions faced with duodenal and jejunal mucosae within 2 hr, and was not detected in the receptor solution, suggesting a slower metabolism compared with AM.

• 공업화학
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• 제20권6호
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• pp.692-695
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• 2009

바닥의 전기난방 장치로 사용할 수 있는 오믹 줄 방전 현상을 이용하는 면상발열체 전극기술을 개발하였다. Super pure black의 탄소재료와 polyvinylidene fluoride의 고분자 재료를 이용하여 제조한 복합 전극 합제를 PET에 박막 도포하여 전극을 제조하였다. 전극에 대한 조성 첨가제로서 multi-walled carbon nanotube와 연옥 분말을 사용하였다. 개발한 면상발열체 전극의 비저항과 전극의 접착강도 및 전극의 강도에 대하여 연구하였다. 연옥 분말의 첨가는 비저항과 강도에 미치는 영향이 적었으며, carbon nanotube의 첨가는 전극의 비전도도와 경도를 향상하였다. 다양한 조성의 오믹 줄 방전 전극의 특성을 연구하였다.

• 대한환경공학회지
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• 제33권10호
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• pp.774-781
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• 2011

지르코늄합금 튜브 제조공정은 튜브 산세 시 질산과 불산을 사용하고 있어 세척 시 발생되는 폐수의 주요 오염물질인 질산성질소와 불소성분을 제거하기 위한 폐수처리는, 1차 화학응집처리에 의한 불소성분 제거공정, 황산화탈질반응을 이용한 SOD (Sulfur Oxidation Denitrification)공법에 의한 독립영양탈질공정, 그리고 2차 화학응집처리공정으로 구성되어 있다. 본 연구에서는, 처리공정에서 불소의 농도가 황산화탈질공정(SOD)의 탈질반응에 미치는 영향과 황산화탈질반응을 유지하기 위한 최적 운전조건을 검토하였다. 황산화탈질 반응은 불소농도 20 ppm 이하에서 거의 영향을 주지 않았으며, NaOH로 pH를 조절하는 것보다 NaOH와 $NaHCO_3$를 혼합하여 pH와 알칼리도를 조절해주는 것이 질소제거당량을 높여주는 효과가 있는 것으로 나타났다. 또한, 황산화탈질미생물에 필요한 미량원소와 알칼리성분이 혼합된 미생물활성화제가 알칼리도를 보충해줄 뿐만 아니라 황산화탈질미생물의 성장과 증식에도 영향을 주었으며, 그 결과 무기계 산업폐수처리 시 필요한 주기적인 미생물 식종 없이 운전이 가능한 결과를 얻었다. 이상의 결과를 통해, 황산화탈질공법(SOD공법)이 산업폐수의 질산성질소제거에 매우 유용한 공법임이 확인되었으며, 미생물활성화제가 황산화탈질미생물의 활성화에 기여함이 밝혀졌다.