• Bulletin of the Korean Chemical Society
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• 제34권8호
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• pp.2451-2454
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• 2013

Poly(methyl methacrylate) coated $BaF_2:Er^{3+}$ nanoparticles were prepared via a novel reverse-emulsion polymerization process using methyl methacrylate as continuous phase and water as dispersed phase. Preparation and coating of $BaF_2:Er^{3+}$ particles were processed in a single step. The resulting polymeric composites show the characteristic $Er^{3+}$ luminescence at excitation of 980 nm and may have potential applications in amplified optical networks.

• The Korean Journal of Ceramics
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• 제5권4호
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• pp.375-378
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• 1999

In tho XRD study of $56ZrF_4 \cdot34BaF_2 \cdot4AIF_3 \cdot(6-x)LaF_3 \cdotxLnF_3$ glassdLn=Ce, Nd, Gd, Th), halo pattern charactarktic fo an amorphous sample appeared. When the halo peak angle ($\theta_p$) was converted into a wavenumber with $Qp=4\pi sinG\pi/\lambda(\lambda$ is the wavolongth of the radialion used), it was found that the Qp values varied almost liuearly with the concentration 01 $LnF_3$. The emissiou spect1.a of $Ce^{3-}$-containing fluoride glasses nnder 273 nm excitation had a peak maximum at ea. 300 nm $(Ce^{3+}$ 5d-4f- transition). The maximal intensity of the fluorescence was observed when the $CeF_3$, content was extremely low (ca. 1 mol%j. DTA measurement revealed tbat these fluoride glasses had two crystallization temperatures. In $56ZrF_4. 34BaF_2. 4NF_3. (6-x)LaF_3 .xNdF_3$ glasses, the actmation energies of crystallization obtained from a Kssinger plot were 1.7 and 5.0 eV for the glass with x=2, and 1.9 and 5.6 eV for the glass with x=4.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.311-312
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• 2007

In this study, composite $BaSrTiO_3$ has been studied for high frequency device applications. Composite $Ba_{0.5}Sr_{0.5}TiO_3$ has high dielectric permittivity and low loss tangent at the relative frequency range from MHz to GHz. 10,30 and 50 wt% of epoxy doped $Ba_{0.5}Sr_{0.5}TiO_3$ powders were prepared with bisphenol A and F polymer employing ball milling process. Epoxy/($BaSrTiO_3$) composites thick films were screen printed on the Cu plated PCB substrates through screen printing methods. The specimens were designed for the embedded capacitor applications. Temperature dependent dielectric permittivity of Epoxy doped $BaSrTiO_3$ ceramics was measured.

• 한국전기전자재료학회논문지
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• 제14권3호
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• pp.197-201
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• 2001

The microwave dielectric properties of (1-x)Ba(Mg$_{1}$3/Ta$_{2}$3/)O$_3$-xBa(Co$_{1}$3/Nb$_{2}$3)O$_3$(x=0.25~0.5) ceramics depending on the Ba(Co$_{1}$3/Nb$_{2}$3/)O$_3$[BCN] contents and the possibility of application as a microwave dielectric resonator were investigated. The specimens were prepared by he conventional mixed oxide method using there sintering temperature of 1575$^{\circ}C$. It was found that Ba(Mg$_{1}$3/Ta$_{2}$3/)O$_3$[BMT] and BCN formed a solid solution with complex perovskite structure. As the mole fraction of BCN increased, dielectric constant increased while temperature coefficient of resonant frequency decreased. The highest value of quality factor, Qxf$_{0}$=138,205GHz, obtained in the sample of 0.9BMT-0.1BCN ceramics. In the range of x$\geq$0.4, the dielectric constant was about 30. The 0.55BMT-0.45BCN ceramics showed excellent microwave dielectric properties with $\varepsilon$$_{r}$=30.84, Qxf$_{0}$=75,325GHz and $\tau$$_{f}$=2.9015ppm/$^{\circ}C$.EX>.EX>.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2000년도 추계학술대회 논문집
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• pp.221-224
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• 2000

The microwave dielectric properties of Ba(Mg$_{1}$3/Ta$_{2}$3/)O$_3$-xBa(Co$_{1}$3/Nb$_{2}$3/)O$_3$[BMT-BCN] ceramics were investigated. The specimens were prepared by the conventional mixed oxide method. It was found that Ba(Mg$_{1}$3/Ta$_{2}$3/)O$_3$ and Ba(Co$_{1}$3/Nb$_{2}$3/)O$_3$ formed a solid solution with complex perovskite structure. Increasing the BCN content, dielectric constant was increased, but temperature coefficient of resonant frequency was decreased. In the range of x$\geq$0.4, dielectric constant was about 30. 0.55BMT-0.45BCN ceramics showed excellent microwave dielectric properties with $\varepsilon$$_{r}$=30.84, Q$\times$f$_{0}$=75,325[GHz] and $\tau$$_{f}$=-2.9015[ppm/$^{\circ}C$].X>].

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 추계학술대회 논문집
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• pp.248-251
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• 1999

The microwave dielectric properties of The Dielectric Properties of $Ba_{1-x}$A$_{x}$(Mg$_{1}$3/Nb$_{2}$3/)O$_3$ (A = Sr, Ca, x = 0, 0.2 ,0.4 ,0.6, 0.8, 1.0) were investigated. In composition of $Ba_{1-x}$A$_{x}$(Mg$_{1}$3/Nb$_{2}$3/)O, densities are decreased with increasing x values. Grain sizes are decreased with Sr content and Increased with Ca content. The hexagonally ordered superstructure was observed in $Ba_{1-x}$Sr$_{x}$(Mg$_{1}$3/Nb$_{2}$3/)O$_3$(BSMN) systems, the intensity of superlattice increased with x value. In $Ba_{1-x}$Cr$_{x}$(Mg$_{1}$3/Nb$_{2}$3/)O$_3$(BSMN) systems, the additional diffraction patterns were shown. The highest value of $\varepsilon$$_{r}$ was shown in x=0.2 of BCMN systems and the value was 41.9. The highest Q$\times$f was shown in x=0.2 of BSMN systems and the value was 68,000. $\tau$$_{f}$ were shown 0 ppm/$^{\circ}C$ near x=0.8.TEX> near x=0.8.0.8.

• 생약학회지
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• 제53권3호
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• pp.170-180
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• 2022

Polycyclic aromatic hydrocarbons(PAHs) contents were analyzed by measuring benz(a)anthracene(BaA), chrysene(Chr), benzo(b)fluoranthene(BbF) and benzo(a)pyrene(BaP), and the related risk characterization was conducted for 113 samples out of 14 different agricultural products used for food and medicine. Detection rate of PAHs was 90.3% as a whole, and the highest one was 80.5% for BaP. The detection rate of BaP exceeding the maximum permitted concentration of Rehmanniae Radix Preparata and Rehmanniae Radix, 5.0 ㎍/kg was 1.8%, and the detection rates of BaA, Chr and BbF were within the range of 2.7~10.6%. The highest average concentration of BaA was 3.41 ㎍/kg detected from Lycii Fructus, while those of Chr, BbF, BaP and PAH4(sum of detected BaA, Chr, BbF and BaP) were 5.00, 1.79, 2.36, 12.36 ㎍/kg, respectively, detected from Rehmanniae Radix Preparata. As for the risk characterization on PAHs, the overall MOE(Margin of Exposure) values were measured within the range of 10⁵~10⁷, which is unlikely to cause direct health concerns, but the worring values of MOE were measured 6.57×10⁴ for BaP and 6.10×10⁴ for PAH4 from Rehmanniae Radix Preparata, which may require an improvement plan to reduce BaP contents.

• 한국광학회지
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• 제9권3호
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• pp.168-174
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• 1998

본 연구에서는 광학매질의 비선형 특징을 측정하기 위해, 자체집속현상을 이용하는 기존의 측정법과는 다르게, 매질을 통과한 광원의 위상섭동으로 인하여 far-field에 발생한 공간적 광장도 분포를 이용하는 far-field 위상 변조량 측정법을 사용하였다. 미선형 매질을 통과한 조사과의 위상 변화가 far-field 영역에서 나타나는 겅간적 위상 변조량을 실험적으로 측정아였고, 이를 전산시\ulcorner을 통하여 비교분석하였다. 파장 616nm, 펄스폭 106ps의 분포궤한 섹소레이저(DFDL)와 파장 308nm인 DFDL의 제2고조파를 조사광으로 사용하였고, 매질 $CS_2$와 $BaF_2$의 비선형 특성을 실험적으로 측정한후 이 값을 전산시늉값과 비교하였다. 이 실험에서 파장 616nm에 대해 $CS_2$와 $BaF_2$의 비선형 굴절률 $1.2{\times}10^{-11}$ esu와 $1.0{\times}10^{-13}$ esu를 각각 얻었고, 파장 308nm에 대해 $BaF_2$의 비선형 흡수계수 $5.0{\times}10^{-11}$cm/W를 얻었다. 이들 값은 지금까지 발표된 값들과 잘 일치한다.

• The Korean Journal of Physiology
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• 제17권1호
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• pp.1-11
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• 1983

1) 토끼동방결절의 작은 절편에 미세 전극 두개로 voltage clamp를 하고 과분극에 의하여 활성화되는 내향전류, $i_f$의 동력학적 성상을 분석하였다. 2) 전류 $i_f$는 $10^{-7}g/ml$ TTX와 2 mM $Mn^{2+}$의 존재하에서 과분극 pulse에 의하여 활성화되었으며 그 범위는 $-45\;mV{\sim}-75\;mV$였다. 전류의 크기와 시간경과는 막전압이 과분극될수록 커지고 빨라졌다. 3) Envelope test결과 $i_f$전류는 단일 gate에 의하여 지수합수적 (exponential)으로 조절됨을 보였다. 4) 2 mM의 $Ba^{2+}$에 의하여$i_f$전류의 크기는 감소하고 시간경과도 느려졌으며 반응속도상수와 gating molecule의 열리고 닫히는 반응계수(rate coefficient; ${\alpha}_s$, ${\beta}_s$)와 막전압 관계곡선을 과분극쪽으로 이동시켰다. 이러한 $Ba^{2+}$의 효과는 24 mM $K^+$에 의하여 일부 상쇄되었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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• pp.335-338
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• 1998

The effect of glass flit addition on microwave dielectric properties of BaTiO$_3$-3TiO$_2$ ceramic was studied. Addition of glass frit to this system obtained sintered sample below sintering temperature 105$0^{\circ}C$. At BaTiO$_3$-3TiO$_2$+ g1ass frit 3wt% + BaWO$_4$6 wt%m, this ceramic showed excellent microwave properties of dielectric constant 34, Q$\times$f 8,100, temperature coefficient of resonant frequency 4 ppm/$^{\circ}C$ .