• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.476-479
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• 2001

The microwave dielectric properties of $[(Pb_{1-x}Ba_{x})_{1/2}La_{1/2}](Mg_{1/2}Nb_{1/2})O_{3}$ ceramics were investigated. When $[(Pb_{0.9}Ba_{0.1})_{1/2}La_{1/2}](Mg_{1/2}Nb_{1/2})O_{3}$ ceramics were sintered at $1250^{\circ}C$ and $1350^{\circ}C$ for 2hr, the microwave dielectric properties were obtained $\varepsilon_{r}=64\sim80$, $Q{\times}f=11,800\sim18,000$. As a result, $[(Pb_{0.9}Ba_{0.1})_{1/2}La_{1/2}](Mg_{1/2}Nb_{1/2})O_{3}$ having $\varepsilon_{r}=80$, $Q{\times}f=11,800$ (at 4 GHz) was developed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.476-479
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• 2001

The microwave dielectric properties of [(Pb$_{1-x}$ Ba$_{x}$)$_{1}$2/La$_{1}$2/](Mg$_{1}$2/Nb$_{1}$2/)O$_3$ ceramics were investigated. When [(Pb$_{0.9}$Ba$_{0.1}$)$_{1}$2/La$_{1}$2/](Mg$_{1}$2/Nb$_{1}$2/)O$_3$ ceramics were sintered at 125$0^{\circ}C$ and 135$0^{\circ}C$ for 2hr, the microwave dielectric properties were obtained $\varepsilon$$_{r}$=64~80, Qxf=11,800~18,000. As a result, [(Pb$_{0.9}$Ba$_{0.1}$)$_{1}$2/La$_{1}$2/](Mg$_{1}$2/Nb$_{1}$2/)O$_3$ having $\varepsilon$$_{r}$=80, Qxf=11,800 (at 4 GHz) was developed.ed.eveloped.ed.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.2
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• pp.27-37
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• 1997

Photoluminescent and cathodoluminescent charcteristics of inorganic luminescent materials were investigated ot develop possible phosphors for thin film electroluminescent (TFEL) device applications. Mg, Zn, and Photoluminescent and cathodoluminescent charcteristics of inorganic luminescent materials were investigated ot develop possible phosphors for thin film electroluminescent (TFEL) device applications. Mg, Zn, and $Si_3N_4$ powders were used to synthesize $(Mg_xZn_{1-x})SiN_2$ host materials. $Tb_4O_7$ and $Eu_2O_3$ powdrs were added as luminescent centers. Very sharp emission spectra of $Tb^{3+}$ ions were observed from $Mg._5Zn._5SiN_2:Tb$ sampels sintered at $1400^{\circ}C$ for an hour and the maximum intensity of emission spectra occured at wavelength of 550nm (green light). Synthetic conditions of $(Mg_xZn_{1-x})SiN_2:Eu$ phosphors were optimized for the hghest luminescence. The Eu concentrations were varied from 0.2% to 1.6%. Before firing, the powders were mixed using ballmills, methanol, acetone, or D.I. water. The Mg/Zn ratio also were varied from x=0.3 to x=0.7. The maximum PL intensity was obtained from a sample with 1.2% Eu concentration and the powder was mixed with methanol and dried before firing. The maximum intensity of the emission spectra occurred t the wavelength of 470nm(blue light). TFEL devices fabricated by using sputter deposition of $(Mg._3Zn._7)SiN_2:Eu$ phosphor layer showed yellowish white emission at the phosphor field of 2MV/cm.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.5
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• pp.415-418
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• 2009

$Zn_{2}SiO_{4}$:Mn green phosphors doped with Mg for PDP were synthesized by solid state reaction method. $Zn_{2}SiO_{4}$:Mn, Mg phosphors with increasing Mg concentration were changed from Rhombohedral to Orthorhombic structure. Photoluminescence intensity of $Zn_{2}SiO_{4}$:Mn phosphors doped with Mg 0.5 mol was definitely higher than that of Mg non-doped sample. The enhanced luminescence with doping Mg in the $Zn_{2}SiO_{4}$:Mn phosphors was interpreted by the increase of energy transfer from host to Mn ions with substitution Mg for Zn in the $Zn_{2}SiO_{4}$:Mn host.

• Journal of Veterinary Clinics
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• v.14 no.2
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• pp.151-160
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• 1997

This study was performed to assess clinical signs, sedative and physiologic effects of a combination of fentanyl, azaperone and xylazine (F-A-X). The experiments were divided into four groups; xylazine 0.1mg/kg (X 0.1), F-A-X 0.05 MG/KG (F-A-X 0.05), F-A-X 0.1 MG/KG (F-A-X 0.1) and F-A-X 0.2mg/kg (F-A-X 0.2). Heart rates were decreased in all groups. Respiratory rates were decreased in other groups, but increased in F-A-X 0.2. Body temperatures were in normal ranges. After administration of F-A-X, most of cattle were recumbency and did not respond to needle prick. Duration of sedation was prolonged with increasing dosages. F-A-X did not induce sufficient analgesia for dehorning. Side effects were salivation and urination in all, but they were much less in F-A-X groups than those in X 0.1. Intermittent apnea and bloat were observed in F-A-X 0.2. Serum chemistry values were in normal ranges exvept for hyperglycemia invreased thorough experimental time. Based on above results, it may be concluded that F-A-X is effective preanesthetic with low dosage of 0.05~0.1 mg/kg being useful for immobilization or manipulation without tissue incision in cattle.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.283-287
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• 2003

Crystal structure of $(Ba_{1-x}La_x)[Mg_{(1+x)/3}Nb_{(2-x)/3}]O_3$ (BLMN) ceramics with $0{\leq}x{\leq}1$ was investigated using synchrotron X-ray powder diffraction (XRD) and high resolution transmission electron microscopy (HRTEM). When La content, x, is above 0.1, the 1:2 ordered hexagonal structure found in $Ba(Mg_{1/3}Nb_{2/3})O_3$ (BMN) was transformed into 1:1 ordered cubic structure. The 1:1 ordered cubic structure was maintained up to x=0.7. However, when x exceeded 0.7, BLMN was transformed 1:1 ordered structure which has cation displacement and in-phase and anti-phase tilt of octahedra.

• Journal of the Korean Society of Tobacco Science
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• v.1 no.2
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• pp.93-102
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• 1979

Chemical compositions of Flue - cured and Burley tobacco leaf and smoke were analyzed to find out simple correlation between compositions. Based on the simple correlation ( $r$ ) data, four regression equations were obtained for dry condensate and nicotine in smoke as follows, $Y_{FT}=\;0.816+4.638X_1+0.346X_2$......................................(1) $Y_{BT}=\;0.235+0.884X_3-0.088X_4$......................................(2) $Y_{FN}=\;0.015+0.090X_5+0.476X_1$......................................(3) $Y_{BN}=-0.026+0.101X_3-0.006X_4$.........................................(4) where, $Y_{FT}$ : dry condensate (mg/cig.) in cigarette smoke of Flue-cured $Y_{BT}$ : dry condensate (mg /cig. ) in cigarette smoke of Burley $Y_{FN}$ : nicotine contents (mg/cig.)in cigarette smoke of Flue-cured $Y_{BN}$ : nicotine contorts (mg/cig. ) in cigarette smoke of Burley $X_1$ : total alkaloid contents (%) of Flue-cured $X_2$ : curde ash contents (%)of Flue -cured $X_3$ : alcohol -benzene extract contents (%) of Burley $X_4$ : curde ash contents (%) of Burley $X_5$ : hexane extract content (%) of Flue -cured Standard deviation for regressions equations were obtained respectively. equation(1),$\pm$3.16 : equation (2),$\pm$1.94 : equation (3),$\pm$0.35 , equation (4) $\pm$ 0.33. Regression equations between dry condensate and nicotine contorts in cigarette smoke were also obtained in the forms of equation(5) and(6) $Y_{FN}$= 0.274 $Y_{FT}$- 3.259............................(5) $Y_{BN}$= 0.249 $Y_{BT}$ - 2.093.............................(6) Standard deviations, $\pm$ 0.061 and $\pm$ 0.152, were obtained for regression equation(5) and (6) respectively.

• Journal of the Korean Society for Heat Treatment
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• v.12 no.1
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• pp.1-8
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• 1999

This study has investigated the effect of aging treatment on the microstructure and mechanical properties of Mg-6Al-xZn(x = 1.5, 2.5) alloys fabricated by the squeeze casting process. The microstructures of as-squeeze cast were composed of pro-eutectic ${\alpha}$, super saturated ${\alpha}$ and ${\beta}(Mg_{17}Al_{12})$ compound. Aged at both $200^{\circ}C$ and $240^{\circ}C$, Mg-6Al-xZn alloys showed the peak hardness due to the formation of ${\beta}(Mg_{17}Al_{12})$ precipitates. The discontinuous precipitates of the lamella type are predominant at $200^{\circ}C$ aging treatment, while the finely dispersed continuous precipitates were dominant at $240^{\circ}C$ aging treatment. Mg-6Al-xZn alloys fabricated by the squeeze casting process had the better combination of tensile strength and elongation compared to the conventionally cast alloys. As zinc contents increased, the tensile strength was increased by the solid solution strengthening effect of zinc.

• Journal of the Korean Ceramic Society
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• v.50 no.6
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• pp.510-517
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• 2013

In this study, the properties of blue inorganic nano-pigments with a spinel structure were systematically investigated. We report the preparation of a blue ceramic nano-pigment and the Co and Ni substitutional effects on the blue color. $MgAl_2O_4$ was selected as the crystalline host network for the synthesis of cobalt and nickel-based blue ceramic nano-pigments. Various compositions of $Co_xMg_{1-x}Al_2O_4$ and $Ni_xMg_{1-x}Al_2O_4$ ($0{\leq}x{\leq}1$) powders were prepared using apolymerized complex method. The obtained powder was preheated at $400^{\circ}C$ for 5 h and then calcined at $1000^{\circ}C$ for 5 h. XRD patterns of the (Co,Mg)$Al_2O_4$ and (Ni,Mg)$Al_2O_4$ samples showed a single phase of the spinel structure in all compositions. TEM results indicated nano-sized pigments for (Co,Mg)$Al_2O_4$ and (Ni,Mg)$Al_2O_4$ with a particle size ranging from 20 to 50 nm. The characteristics of the color tones of (Co,Mg)$Al_2O_4$ and (Ni,Mg)$Al_2O_4$ were analyzed by CIE $L^*a^*b^*$ measurements. In addition, the thermal stability and the binding characteristics of (Co,Mg)$Al_2O_4$, (Ni,Mg)$Al_2O_4$ are discussed in terms of the TG-DSC and FT-IR results, respectively.

• Journal of the Korean Ceramic Society
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• v.36 no.3
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• pp.325-331
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• 1999

SrWO4가 첨가된 (Sr1-xBax)(Mg1/3Nb2/3)O3의 마이크로파 유전특성에 관하여 조사하였다. 관찰된 조성영역에서 Sr(Mg1/3Nb2/3)O3과 Ba(Mg1/3Nb2/3)O3은 (Sr1-xBax)(Mg1/3Nb2/3)O3고용체를 형성하고 SrWO4의 첨가는 고용체의 소결성을 향상시켜 소결온도 155$0^{\circ}C$에서 상대밀도 97% 이상을 얻었다. 소결한 시편의 EDS분석결과, SrWO4의 첨가량이 많은 시편에서 2차상이 존재하는 것을 알수 있었다. 순수한 Sr(Mg1/3Nb2/3)O3에 SrWO4를 0.01 mole첨가하여 1550~1$600^{\circ}C$에서 소결한 시편의 유전특성은 $\varepsilon$r 30, Q$\times$fo$\geq$55000,$ au$f -23 ppm/$^{\circ}C$이었다. 0.01 mole SrWO4가 첨가된 (Sr1-xBax)(Mg1/3Nb2/3)O3 고용체의 유전율과 온도계숙가 x에 따라 점차적으로 계속 증가하였고 Q$\times$fo는 x$\leq$0.25에서 x에 따라 감소하고 x$\geq$0.3에서 다시 증가하였다. (Sr0.65Ba0.35)(Mg1/3Nb2/3)O3+0.01SrWO4의 조성을 갖는 시편에서 $\varepsilon$r 34.4, Q$\times$fo$\geq$55000,$\tau$f 0 ppm/$^{\circ}C$이었다.