• 한국세라믹학회지
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• 제37권10호
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• pp.962-967
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• 2000

산소 결핍 페라이트 (oxygen deficient ferrites, ODF) MF $e_2$ $O_{4-}$$\delta$/는 약 30$0^{\circ}C$의 낮은 온도에서 온실가스중 하나인 $CO_2$를 C와 $O_2$로 분해시킨다. 본 연구에서는 $CO_2$분해 촉매로서 3원계 초미세 페라이트 N $i_{x}$Z $n_{1-x}$F $e_2$ $O_4$와 N $i_{x}$ $Co_{1-x}$F $e_2$ $O_4$를 수열합성법과 공침법 등의 습식 합성법으로 각각 합성하여 이들 분말의 특성과 $CO_2$분해 특성을 고찰하였다. 페라이트의 XRD 결과, 결정구조는 모두 전형적인 스피넬 구조로 동일하게 나타났다. BET 비표면적은 수열합성법으로 제조한 3원계 페라이트의 경우 110$m^2$/g 이상으로 공침법으로 제조한 페라이트보다 비교적 큰 값을 나타냈고 분말 입자크기 또한 약 10nm의 매우 미세한 분말을 얻을 수 있었다. 3원계 산소 결핍 페라이트의 $CO_2$분해 효율은 공침법으로 합성한 것보다 수열합성법으로 합성한 것이 더 우수하게 나타났으며, N $i_{x}$ $Co_{1-x}$F $e_2$ $O_{4-}$$\delta$/보다 N $i_{x}$Z $n_{1-x}$F $e_2$ $O_{4-}$$\delta$/가 우수한 것으로 나타났다.

• 한국자기학회지
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• 제13권3호
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• pp.121-126
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• 2003

(N $i_{0.2}$C $u_{0.2}$Z $n_{0.6}$)$_{1.085}$(F $e_2$ $O_3$)$_{0.915}$의 기본 조성에 첨가제 Sn $O_2$, CaO 첨가량과 ferrite의 공정을 변화시켜 시편의 전자기적 특성 및 미세구조를 조사하였다. 첨가제에 따른 입자크기의 변화는 거의 없었다. (N $i_{0.2}$C $u_{0.2}$Z $n_{0.6}$)$_{1.085}$(F $e_2$ $O_3$)$_{0.915}$을 소결시 1300 $^{\circ}C$에서 소결하는 것보다 1150 $^{\circ}C$에서 소결한 소결체의 손실이 더욱 적었다. CaO만 첨가할 때 0.2 wt%가 소결밀도를 크게하여 손실을 줄여주는 첨가제로 사용 가능함을 확인하였다 Sn $O_2$차 Ca $O_2$함께 첨가시 SnO2$_2$ 0.06 wt%, CaO 0.4 wt%가 손실을 크게 줄여 주는 것으로 조사되었다.

• 충청수학회지
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• 제20권4호
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• pp.433-438
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• 2007

Let $\mathbb{A}=\mathbb{F}_q[T]$ and $k=\mathbb{F}_q(T)$. Assume q is odd, and fix a prime divisor ${\ell}$ of q - 1. Let P be a monic irreducible polynomial in A whose degree d is divisible by ${\ell}$. In this paper we define a subgroup $\tilde{C}_F$ of $\mathcal{O}^*_F$ which is generated by $\mathbb{F}^*_q$ and $\{{\eta}^{{\tau}^i}:0{\leq}i{\leq}{\ell}-1\}$ in $F=k(\sqrt[{\ell}]{P})$ and calculate the unit-index $[\mathcal{O}^*_F:\tilde{C}_F]={\ell}^{\ell-2}h(\mathcal{O}_F)$. This is a generalization of [3, Theorem 16.15].

• 한국염색가공학회지
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• 제32권4호
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• pp.217-225
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• 2020

In this study, the dyeing characteristics of nylon fabric which is dyed with supercritical fluid were investigated. There were two dyes used in the dyeing experiment: C.I. Disperse Red 167 and C.I. Disperse Violet 93. Dyeing temperature, pressure, and leveling time were fixed at 110℃, 250bar, 60minutes, and the experiment was conducted with dyeing concentration of 0.1, 0.3, 0.5, and 0.85% o.w.f. The analysis of the experimental results was found out through the measurement of washing fastness and color coordinate. In addition, the calibration curve of each dye was drawn up and the amount of remaining dye was checked by measuring the absorbance of the residual dye. As a result of color difference measurement, as the concentration increased, the L⁎ value decreased and the K/S value increased. However, the increase in K/S value compared to the amount of input decreased as the concentration increased. The comparative experiment on the amount of residual dye(C.I. Disperse Red 167) in the pot showed that 99.14% of the amount was dyed at the concentration of 0.1% o.w.f, while it rapidly decreased to 77% at 0.85% o.w.f. C.I. Disperse Violet 93 dye also decreased from 0.5% o.w.f to 93.91%. In the washing fastness experiment of both dyes, the level of washing fastness began to decrease from samples dyed at 0.5% o.w.f. It may be because the simply absorbed dye was produced instead of completely being fixed in the amorphous region of the nylon fiber.

• E2M - 전기 전자와 첨단 소재
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• 제9권9호
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• pp.906-910
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• 1996

Ferroxplana N $i_{2}$Y(B $a_{2}$N $i_{2}$F $e_{12}$ $O_{22}$ ) magnetic particles, which is one of the hexagonal ferrite were synthesized by a coprecipitation method. The coprecipitates were prepared by adding aqueous solution of BaC $I_{2}$ - 2 $H_{2}$O, NiC $I_{2}$ - 6 $H_{2}$O and FeC $I_{3}$ - 6 $H_{2}$O(of which the mole ratio is $Ba^{+2}$ : N $i^{+2}$ : F $e^{3+}$= 1 : 1 : 6) to a mixture of NaOH and N $a_{2}$C $O_{3}$. The shape of Ferroxplana N $i_{2}$Y magnetic particles obtained at 1, 100(.deg. C) was hexagonal plate-like, average particle size and aspect ratio were 2(.mu.m) and 7, respectively.y.

• 한국재료학회지
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• 제7권10호
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• pp.872-876
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• 1997

(1-x)CaTi $O_{3}$-xLa(Z $n_{1}$2/ $Ti_{1}$2/) $O_{3}$의 마이크로 유전특성을 조사하였다. x가 증가함에 따라 비유전율과 공진주파수의 온도계수는 감소하였으며, Qㆍ $f_{0}$는 증가하였다. 그 결과 x=0.5인 (C $a_{0.5}$L $a_{0.5}$)( $Ti_{0.75}$Z $n_{0.25}$) $O_{3}$의 조성에서 $\varepsilon$$_{r}$=51, Qㆍ $f_{0}$=38,000 (at 7 GHz), $\tau$$_{f}$=+5ppm/$^{\circ}C$의 유전특성이 나타났다. (C $a_{0.5}$L $a_{0.5}$)( $Ti_{0.75}$Z $n_{0.25}$) $O_{3}$조성의 소결온도를 저하시키기 위하여 B $i_{2}$ $O_{3}$를 주조성으로한 소결체를 첨가하여 소결 및 유전특성을 조사하였다. 1wt% 0.76B $i_{2}$ $O_{3}$-0.24NiO가 첨가된 경우 소결온도는 15$0^{\circ}C$ 낮아졌으며, 비유전율 ($\varepsilon$$_{r}$), 공진주파수의 온도계수($\tau$$_{f}$), Qㆍ $f_{0}$가 각각 50+5ppm/$^{\circ}C$, 35,000인 마이크로파 유전특성이 얻어졌다. 또한 3wt%의 0.76B $i_{2}$ $O_{3}$-0.24NiO가 첨가된 경우 소결온도는 20$0^{\circ}C$ 저하되었고, 비유전율 ($\varepsilon$$_{r}$)과 공진주파수의 온도계수 ($\tau$$_{f}$)는 변하기 않았으나, Qㆍ $f_{0}$값이 38,000에서 25,000으로 저하되었다. 25,000으로 저하되었다.되었다.되었다.되었다.

• Bulletin of the Korean Chemical Society
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• 제23권2호
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• pp.229-240
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• 2002

Quantum mechanical calculation is performed for the $O(^1D)$ + HCl ${\rightarrow}$OH + Cl reaction using Reactive Infinite Order Sudden Approximation. Shifting approximation is also employed for the l ${\neq}$ 0 partial wave contributions. Various dynamical quantities are calculated and compared with available experimental results and quasiclassical trajectory results. Vibrational distributions agree well with experimental results i.e. product states mostly populated at $v_f$ = 3, 4. Our results also show small peak at $v_f$ = 0, which indicates bimodal vibrational distribution. The results show two significant broad peaks in ${\gamma}_i$ dependence of the cross section, one is at ${\gamma}_i$ = $15^{\circ}-35^{\circ}$ and the another is at ${\gamma}_i$= $55^{\circ}-75^{\circ}$ which can be explained as steric effects. At smaller gi, the distribution is peaked only at higher state ($v_f$ = 3, 4) while at the larger gi, both lower state ($v_f$ = 0) and higher state ($v_f$ = 3, 4) are significantly populated. Such two competing contributions (smaller and larger ${\gamma}_i$) result in the bimodal distribution. From these points we suggest two mechanisms underlying in current reaction system: one is that reaction occurs in a direct way, while the another is that reaction occurs in a indirect way.

• 농업과학연구
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• 제11권1호
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• pp.176-181
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• 1984

살충성 O,O-diethylphenylphosphate (A)와 3,5-dimethylphenyl-O,O-diethylphosphate 유도체 (B)에 의한 acetylcholinesterase(Ach E)의 phosphorylation 반응에 미치는 정량적인 자유에너지 관계(LFER)를 알아보기 위하여 Ach E의 두 작용점인 esteratic-anionic site에 대응하는 (A) 및 (B)의 P원자 및 meta 위치간의 공간직선 거리 및 알짜전하를 확장 H$\ddot{u}$ckel이론(EHT)에 의한 MO 계산 방법으로 계산하고 여러 가지 치환기상수와 $pI_{50}$ 상수를 Hammett 및 Okamoto-Brown식, Taft와 Swaln-Lupton의 DSP식에 적용한 회귀분석 결과로부터 살충작용에 미치는 정량적인 자유에너지 관계, %R과 %F를 계산하여 검토하였다. 즉, (A) 및 (B)의 살충효과는 서로 비슷하였으며 blending coefficient (${\lambda}$)는 모두 ${\lambda}$<1의 값을 나타내었다. (A) 및 (B)의 resonance effect (%R)와 field effect (%F)는 각각 %R=33.5, %F=66.5 그리고 %R=2, %F=98로 각각 계산되었는데(B)와 같이 phenyl group에 bulky한 소수성의 methyl group이 결합될수록 resonance effect($R_{\pi}$)보다는 direct through space field effect ($F_D$)가 아닌 through space field effect가 더 크게 영향을 미치게 된다는 사실을 알 수 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.331-334
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• 2001

In this study, the magnetic properties for Ni-Zn ferrite were investigated as the function of $Co_3$ $O_4$ additive contents which was predicted to improve the resonance frequency. Toroid specimens with the composition of N $i_{0.8-x}$Z $n_{0.2+x}$F $e_2$ $O_4$(x = 0, 0.05, 0.1, 0.15) ferrites were preparation by conventional ceramic processing technique. The maximum resonance frequency of 19.905 MHz and the permeability of 90.88 in 10 MHz were attained to the N $i_{0.8}$Z $n_{0.2}$F $e_2$ $O_4$with $Co_3$ $O_4$0.3 wt%. Both of the permeability in 10 MHz and the resonance increased to 107.11 and 19.005 MHz respectively for the N $i_{0.8}$Z $n_{0.2}$F $e_2$ $O_4$with $Co_3$ $O_4$wt% than the N $i_{0.8}$Z $n_{0.2}$F $e_2$ $O_4$/ with the free $Co_3$ $O_4$composition.composition.

• 한국전기전자재료학회논문지
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• 제16권7호
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• pp.604-610
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• 2003

The effects of sintering additives such as B $i_2$ $O_3$ and $V_2$ $O_{5}$ on the microwave dielectric and sintering properties of (Z $n_1$$_{-xM}$ $g_{x}$)Ti $O_3$ system were investigated. Highly dense samples were obtained for (Z $n_{0.8}$M $g_{0.2}$)Ti $O_3$ at the sintering temperature range of 870~90$0^{\circ}C$ with B $i_2$ $O_3$ and $V_2$ $O_{5}$ additions of 〈1 wt.%, respectively. The microwave dielectric properties of (Z $n_{0.8}$M $g_{0.2}$)Ti $O_3$ with 0.45 wt.%B $i_2$ $O_3$ and 0.55 wt.% $V_2$ $O_{5}$ sintered at 90$0^{\circ}C$ were as follows : Q$\times$ $f_{o}$ = 50,800 GHz, $\varepsilon$$_{r}$ = 22, and $\tau$$_{f}$ = -53 ppm/$^{\circ}C$. In order to improve temperature coefficient of resonant frequency, Ti $O_2$ was added to the above system. The optimum amount of Ti $O_2$ was 15 moi.% when sintered at 87$0^{\circ}C$, at which we could obtain following results: Q$\times$ $f_{o}$ = 32,800 GHz, $\varepsilon$$_{r}$ = 26, and$\tau$$_{f}$ = 0 ppm/$^{\circ}C$.EX>.EX>.EX>.EX>.EX>.EX>.EX>.