• The Korean Journal of Pesticide Science
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• v.9 no.1
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• pp.97-101
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• 2005

Flupyrazofos (O,O-diethyl O-1-phenyl-3-trifluoromethylpyrazo-5-yl phosphorothioate) is an organophosphorus insecticide with a pyrazole moiety which is newly developed and commercialized by SUNGBO chemical company and Korean Research Institute of Chemical Technology for effectively control against diamond back moth. This study was conducted to determine the composition and quantity of impurities in technical 1 (94.5%), technical 2 (97.6%) and purified (99.2%) flupyrazofos using GLC/MSD. Bimolecular inhibition rate constant($k_i$) with acethylcholinesterase (in vitro) and $I_{50}$ with mouse brain acetylcholinesterase (in vivo) were measured for comparing inhibitory patterns of two technicals and purified flupyrazofos. Impurities of flupyrazofos were identified as O,O,O-triethylthio-phosphoric acid (TEA), 1-phenyl-3-trifluoromethyl-5-ethoxy pyrazole(PTMEP), O,O-diethyl O-1-phenyl-3-trifluoromethylpyrazo-5-yl phosphoric acid ester(flupyrazofos oxen), O,S-diethyl O-1-phenyl-3-trifluoromethylpyrazo-5-yl phosphorothionate (S-ethyl flupyrazofos). In in vitro, technical 1 showed the fastest inhibition on AChE activity among them. And technical 1 and 2 showed 40% higher in vivo inhibition against mouse brian AChE than purified flupyrazofos did. These results could be caused by the impurities such as flupyrazofos oxen and S-methyl flupyrazofos contained in technical grades of flupyrazofos.

• Journal of the Korean Ceramic Society
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• v.25 no.5
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• pp.488-494
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• 1988

Effects of MnO2 addition on themicrostructure, dielectric and piezoelectric properties of Rhombohedral, Tetragonal and Morphotropic phase boundary(MPB) in Pb(Ni1/3Nb2/3)O3-PbTiO3-PbZrO3 system were investigated and respectively the amount of MnO2 addition was 0, 0.2, 0.5, 1.0, 3.0wt%. In the tetragonal region, compared with the Rhombohedral and Morpotropic phase boundary, Mechanical quality factor(Qm), Curie temperature(Tc) and Dissipation factor were promoted by addition of MnO2. According to the results of the microstructure, dielectric and piezoelectric properties, the solid solution range of MnO2 addition in this system was 0.2-0.5wt%.

• Nuclear Engineering and Technology
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• v.16 no.2
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• pp.58-63
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• 1984

Paper electrophoretic separation of octahedrally bonded (Ruc $l_{6}$ )$^{3-}$ has been carried out by using the specially designed migration apparatus. The supporting electrolyte solutions are as follows: 0.1M-HCl $O_4$, 0.05 M-HCl+0.09M-KCl, 0.1M-HCl, 5$\times$10$^{-3}$ M-NTA, 0.01M-HCl, 0.01M-HCl $O_4$, 0.01M-citric acid, 0.01M-K $H_2$P $O_4$+0.01M-N $a_2$HP $O_4$, 0.05M-borax, 0.025M-N $a_2$C $O_3$+0.025M-NaHC $O_3$, 0.01M-N $a_3$P $O_4$, 0.01M-NaOH and 0.1 M-NaOH. The (Ruc $l_{6}$ )$^{3-}$ appears in 2 to 4 peaks and is found in several chemical species such as (RuCl ($H_2O$)$_{5}$ )$^{2+}$, cis and trans (RuC $l_2$($H_2O$)$_4$)$^{1+}$, (RuC $l_3$($H_2O$)$_3$)$^{0}$ , (RuC $l_4$($H_2O$)$_2$)$^{1-}$, (RuC $l_{5}$ ($H_2O$))$^{2-}$ and (RuC $l_{6}$ )$^{3-}$. The retention value has been found to be highest in the 0.025M-N $a_2$C $O_3$+0.025M-NaHC $O_3$ electrolyte solution.n.

• Korean Chemical Engineering Research
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• v.43 no.1
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• pp.140-145
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• 2005

The desulfurization abilities using GC/microreactor have been examined for $CuO-Fe_2O_3$ sorbents with respect to calcination temperatures of 700, 900 and $1,100^{\circ}C$. CuO was used as a main active component, $Fe_2O_3$ was used as an additive one and 25 wt% $SiO_2$ was used as a support. The desulfurization reaction temperature was $500^{\circ}C$ and the regeneration reaction temperature was $700^{\circ}C$. From the XRD results, the $CuFeO_2$ compound has been observed for the fresh sorbent calcined at $1,100^{\circ}C$ and the $CuFeS_2$ compound for the reacted sorbent calcined at $1,100^{\circ}C$. By the BET results, however any significant differences among sorbents calcined at the three different temperatures of 700, 900 and $1,100^{\circ}C$ haven't been observed. Especially CFS1 (CuO : $Fe_2O_3$ : $SiO_2$=67.5 wt% : 7.5 wt% : 25 wt%) sorbent calcined at $1,100^{\circ}C$ maintained about 10 g sulfur/100 g sorbent for 100 cycles by the cyclic test.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.5
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• pp.402-410
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• 2000

The electrical properties and stability of Pr$_{6}$/O$_{11}$-based ZnO wvaristors consisting of ZnO-Pr$_{6}$/O$_{11}$-CoO-Dy$_{2}$/O$_{3}$ based ceramics were investigated in the Dy$_{2}$/O$_{3}$ additive content range o 0.0 to 2.0 mol%. The density was nearly constant 5.62 g/cm$^3$corresponding to 97% of theoretical density as Dy$_{2}$/O$_{3}$ additive content increases up to 0.5 mol%. However the density decreased as Dy$_{2}$/O sub 3/ additive content is further additive content. Pr$_{6}$/O$_{11}$-based ZnO varistors doped with 0.5mol% Dy$_{2}$/O$_{3}$ exhibited a good nonlinearity, which is 37.76 in the nonlinear exponent and 5.36 $mutextrm{A}$ in the leakage current. And they exhibited very stress (0.80 V$_{1mA}$/9$0^{\circ}C$/12h)+(0.85 V$_{1mA}$/115$^{\circ}C$/12h)+(0.95 V$_{1mA}$/1$25^{\circ}C$/12h). Consequently it was estimated that ZnO-0.5 mol% Pr$_{6}$/O$_{11}$-1.0 mol% CoO-0.5 mol% Dy$_{2}$/O$_{3}$ based ceramics will be sufficiently used as a basic composition to develop the advanced Pr$_{6}$/O$_{11}$-based ZnO varistors in the future.he future.uture.he future.

• Journal of the Korean Ceramic Society
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• v.35 no.4
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• pp.364-370
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• 1998

Boron-phoshor-silicate glass was fabricated on Si substrates by FHD(Flame Hydrolysis Deposition) The microstructrue of silica soot deposited at various conditon such as composition and substrate temperature was analysed by SEM. After consolidation the refractive index and composition of the silica layer were in-vestigated. For refractive index control B, P and Ge were used as additive elements while B and Ge oxides are easily mixed into $SiO_2$, P oxide($B_2O_3$) doping is difficult because of the volatile property due to low melt-ing point. Boron-phosphorous-silicate glass (BPSG) layer were fabricated using bertical torch and optimized flame temperature substrate temperature and distance of torch and substrate. P concentration of BPSG lay-er measured 3.3 Wt% and the consolidation temperature was lower than $1180^{\circ}C$. The measured refractive index of BPSG silica layer in $1.55\;\mu\textrm{m}$ wavelength was $1.4480{\pm}1{\times}10^{-1}$ and the thickness was $22{\pm}1\;\mu\textrm{m}$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.245-245
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• 2007

본 연구는 $Bi_2O_3$, ZnO 및 $Nb_2O_5$로 이루어진 두 가지의 $Bi_2(Zn_{1/3}Nb_{2/3})_2O_7$와 $(Bi_{1.5}Zn_{0.5})(Zn_{0.5}Nb_{1.5})O_7$ pyrochlore를 제조한 후, ZBS 및 BZBS 유리를 각각 첨가하여 저온 소결 및 마이크로파 유전 특성을 고찰하였다. 두 가지의 pyrochlore에 대하여 하소 온도에 따른 상 합성 유무를 고찰한 결과 $900^{\circ}C$에서 단일 상을 갖는 pyrochlore를 제조할 수 있었다. 두 가지의 pyrochlore에 ZnO-rich ZBS 유리와 $Bi_2O_3$-rich BZBS 유리를 3, 5 wt%로 첨가한 후 $800{\sim}950^{\circ}C$에서 소결한 결과 ZBS 및 BZBS 유리를 5wt%를 첨가하였을 때 $900^{\circ}C$에서 소결이 가능하였다. 또한 마이크로파 유전 특성을 고찰한 결과, $(Bi_{1.5}Zn_{0.5})(Zn_{0.5}Nb_{1.5})O_7$의 pyrochlore는 고주파에서 유전 특성 측정이 되지 않았다. $Bi_2(Zn_{1/3}Nb_{2/3})_2O_7$의 pyrochlore의 경우 5 wt% ZBS 및 BZBS 유리를 첨가하여 $900^{\circ}C$에서 소결한 시편의 마이크로파 유전 특성은 ${\varepsilon}_r$= 62.8~68.3, $Q{\times}f$ value= 3,500~2,700 GHz을 나타내었다.

• Journal of the Korean Ceramic Society
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• v.35 no.2
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• pp.123-128
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• 1998

Multilayer ceramic capacitors(MLCC) were prepared by laminating the layer of composition with dif-ferent Curie temperature to improve temperature coefficient in the Pb(Mg1/3Nb2/3)O3-PbTiO3 binary system. Green sheet was formed by tape casting using Pb(Mg1/3Nb2/3)O3-PbTiO3 and PbTiO3 synthesized with solid state reaction of PBO. Nb2O5 MgO and TiO2. Green sheet with electrode of 70Ag-30Pd was laminated under 300 kg/cm2 at 70$^{\circ}C$ and sintered at 1100$^{\circ}C$ for 2hr. Curie temperatues for MLCC with 10 layers of pure PMN and 0.9PMN-0.1PT were lowered to -22$^{\circ}C$ and 36$^{\circ}C$ respectively. MLCC with 7 layers of PMN and 3 layers of 0.9PMN-0.1PT showed nearly zero temperature coefficient of capacitance in the range of -20∼30$^{\circ}C$ and sum of dissipation factor of each layer.

• Journal of the Korean Ceramic Society
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• v.25 no.6
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• pp.571-576
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• 1988

The microstructure and electrical properties of 0.02Pb[Cd1/2W1/2)O3-0.505PbZrO3-0.475PbTiO3 with MnO2 addition have been investigated. The amount of MnO2 addition was 0, 0.2, 0.4, 0.6, 0.8, 1wt%, respectively. When MnO2 is added up to 0.2wt%, Mn3+ which is substituted for Ti4+ site make hole and act as a acceptor. When MnO2 is added over 0.2wt% Mn3+ which is substituted for Cd2+ site create electron and act as a donor. The variation of grain size show that it was rapidly increased by 0.4wt% addition of MnO2, and while that in the range of over 0.6wt% addition of MnO2 it was decreased. The solid solution range of MnO2 that assumed in this composition according to the variations of microstructure and electrical properties was 0.4-0.6wt%.

• Journal of Magnetics
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• v.15 no.4
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• pp.165-168
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• 2010

$Li_{0.1}Zn_{0.9}O$ and $MgFe_2O_4$ powders were synthesized using chemical methods and mixed in different proportions to prepare a mixture of $Li_{0.1}Zn_{0.9}O$ and $MgFe_2O_4$ that was thermally treated between 900 to $1100^{\circ}C$ for 1 hour. Structural characterization was done using X-ray powder diffraction measurements. Grain sizes and morphologies of $Li_{0.1}Zn_{0.9}O$, $MgFe_2O_4$, and $Li_{0.1}Zn_{0.9}O+MgFe_2O_4$ samples were observed using a scanning electron microscope. Variation of magnetic properties of the $Li_{0.1}Zn_{0.9}O+MgFe_2O_4$ samples due to the addition of $Li_{0.1}Zn_{0.9}O$ was studied in relation to the structural changes occurring due to the thermal treatment. In particular, changes in the cationic distribution between the tetrahedral and octahedral positions were studied with respect to the increase of the annealing temperature. Magnetization was found to be dependent on the cations distributed in the tetrahedral and octahedral sites of the $MgFe_2O_4$.