• Proceedings of the Korean Ceranic Society Conference
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• 2003.10a
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• pp.121.2-121
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• 2003

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.3
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• pp.142-145
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• 2013

The upconversion (UC) luminescence of $Li^+/Er^{3+}/Yb^{3+}$ co-doped $CaWO_4$ phosphors and effects of $Yb^{3+}$ concentration are investigated in detail. Single crystallized $CaWO_4$ : $Li^+/Er^{3+}/Yb^{3+}$ phosphor can be obtained, co-doped up to 35.0/5.0/30.0 mol% ($Li^+/Er^{3+}/Yb^{3+}$) by solid-state reaction. Under 980 nm excitation, $CaWO_4$ : $Li^+/Er^{3+}/Yb^{3+}$ phosphor exhibited strong green UC emissions visible to the naked eye at 530 and 550 nm induced by the intra 4f transitions of $Er^{3+}$ ($^4H_{11/2}$, $^4S_{3/2}{\rightarrow}^4I_{15/2}$). The optimum doping concentrations of $Yb^{3+}$ that would result in the highest UC luminescence were determined, and a possible UC mechanism that depends on the pumping power is discussed in detail.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.6
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• pp.477-480
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• 2010

In this study, we fabricate 3 wt% $Li_2CO_3$ doped $(Ba,Sr)TiO_3$ thick films on the Ag/Pd bottom electrode printed $Al_2O_3$ substrates for the LTCCs (low temperature co-fired ceramics) applications. From the X-ray diffraction analysis, 3 wt% $Li_2CO_3$ doped BST thick films on the Ag/Pd printed $Al_2O_3$ substrates, which sintered at $900^{\circ}C$, showed perovskite structure without any pyro phase. The dielectric properties of 3 wt% $Li_2CO_3$ doped BST thick films are measured from 1 kHz to 1 MHz. To investigate the electrical properties of 3 wt% $Li_2CO_3$ doped BST thick films, we employ the impedance spectroscopy. The complex impedance of 3 wt% $Li_2CO_3$ doped BST thick films are measured from 20 Hz to 1 MHz at the various temperatures.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.3
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• pp.120-123
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• 2005

The 5 mol% ZnO doped $LiNbO_3$ film and the 2 mol% MgO doped $LiNbO_3$ film were grown on the $LiNbO_3$ (001) substrate by liquid phase epitaxy (LPE) method with $Li_2CO_3-V_2O_5$ flux system. The crytsallinity and the lattice mismatch between $Zn:LiNbO_3$, film and $Mg:LiNbO_3$, film were analyzed by x-ray rocking curve (XRC). In addition, the ZnO and MgO distribution in the cross-section of the multilayer thin films was observed using electron probe micro analyzer (EPMA).

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.3-4
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• 2006

${Li_2}{CO_3}$ and MgO doped paraelectric ${Ba_{0.5}}{Sr_{0.5}}{TiO_3}$, materials were prepared and compared for LTCC applications. In these days LTCC (Low Temperature Co-fired Ceramics) technology has been widely employed for electronic modules for the communication systems such as front-end modules, antenna modules, and switching modules. In this paper, 1 ${\sim}$ 5 wt % of ${Li_2}{CO_3}$, and 30 wt % of MgO were added to ${Ba_{0.5}}{Sr_{0.5}}{TiO_3}$, respectively. The crystalline properties and electrical properties will be compared and discussed.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.12
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• pp.1347-1352
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• 2005

[ $H_2S$ ] removal reaction using $Li_2ZrO_3/honeycomb$ has been carried out in a fixed bed reactor for the cleaning of syngas from the waste gasifier. $Li_2ZrO_3$ was synthesised using reagent-grade $Li_3CO_3$ and $ZrO_2$ with suitable amount of ethanol in a 1:1 ratio. And then $Li_2ZrO_3$ were calcined in air at $850{\sim}1000^{\circ}C$ for 14 h. The optimum condition of $H_2S$ removal reaction is around 20 wt% $Li_2ZrO_3$/honeycomb at 300 mL/min and $700^{\circ}C$. At this condition, removal amount of $H_2S$ was about 0.337 $g^{H_2S}/g^{sorbent}$. Addition of $K_2CO_3$, $Na_2CO_3$, NaCl and LiCl in the $Li_2ZrO_3$ remarkably improves the $H_2S$ removal capacity of modified $Li_2ZrO_3$/honeycomb up to 23%. Analyses of $Li_2ZrO_3/honeycomb$ sorbent by SEM and XRD showed that $Li_2ZrO_3$ was uniformly impregnated into honeycomb up to considerable amounts. Furthermore, the physicochemical properties of the sorbent did not vary much up to $1000^{\circ}C$.

• Journal of Electrochemical Science and Technology
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• v.7 no.4
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• pp.245-250
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• 2016

The layered $Na_{0.6}Li_{0.6}[Mn_{0.72}Ni_{0.18}Co_{0.10}]O_2$ composite with well crystalized and high specific capacity is prepared by molten-salt method and using the substitution of Na for Li-ion battery. The effects of annealing temperature, time, Na contents, and electrochemical performance are investigated. In XRD analysis, the substitution of Na-ion resulted in the P2-$Na_{2/3}MO_2$ structure ($Na_{0.70}MO_{2.05}$), which co-exists in the $Na_{0.6}Li_{0.6}[Mn_{0.72}Ni_{0.18}Co_{0.10}]O_2$ composites. The discharge capacities of cathode materials exhibited $284mAhg^{-1}$ with higher initial coulombic efficiency.

• Journal of the Korean Ceramic Society
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• v.40 no.3
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• pp.249-254
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• 2003

AI, AIN and additives such as Li$_2$CO$_3$, Y$_2$O$_3$ and CaCO$_3$ which promoted nitridation were mixed, formed and heat-treated in nitrogen atmosphere. The effect of solvent, additive and temperature on nitridation of AI-AIN system was studied. When ethanol containing 1 wt% oleic acid was used as a mixing solvent, the formation of oxide was minimized due to surface modification of AI and AIN particles. The addition of Li$_2$CO$_3$ or CaCO$_3$ as an additive extremely diminished the formation of oxide which formed during heat treatment for nitridation compared with the addition of Y$_2$O$_3$.

• Applied Chemistry for Engineering
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• v.16 no.3
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• pp.372-378
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• 2005

Calcium Carbonate Saturation Index (LI: Langelier Index), an indicator of $CaCO_3(s)$ saturation, indicates corrosiveness of drinking water and it has been used to monitor drinking water conditions in USA, E.U, and Japan. The objective of this research was to measure LI parameters including water temperature, pH, total alkalinity, calcium ion concentration, and electric conductivity, and to evaluate possibility of using LI in domestic system. Results showed that water temperature varied from 2.0 to $26^{\circ}C$ during 15 months, indicating an average annual temperature of $23.9^{\circ}C$. Total alkalinity was from 20 to 45 mg/L. The concentration difference between total alkalinity and $HCO_3{^-}$ value was hardly observed; the concentration of total alkalinity can be replaced by that of $HCO_3{^-}$. Tap water had a medium corrosiveness since LI values were from 2.0 to 0.5. To reduce the corrosiveness and to increase LI values of drinking water, the results of this study showed that chemicals such as $Ca(OH)_2$, $CaCO_3$, NaOH, or $NaHCO_3$ should be added to water treatment plants.

• Journal of the Korean Electrochemical Society
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• v.10 no.1
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• pp.48-51
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• 2007

In order to investigate the effects of particle size and specific surface area(BET area) of spinel powder, $LiMn_2O_4$ were synthesized using metal oxide precursor by co-precipitation method(CoP) and solid state reaction (SSR) .X-ray diffraction(XRD) patterns revealed that the both prepared powder has a well developed spinel structure with Fd3m space group. The $LiMn_2O_4$ prepared by co-precipitation showed spherical morphology with narrow size distribution. However, the $LiMn_2O_4$ prepared by solid state reaction showed relatively smaller particles with irregular shape. The measured BET areas of the powers are $0.8m^2g^{-1}$ (CoP) and $3.6m^2g^{-1}$(SSR). The electrochemical performance of the Prepared $LiMn_2O_4$ powders was evaluated using coin type cells(CR2032) at elevated temperature ($55^{\circ}C$). The $LiMn_2O_4$ prepared by co-precipitation showed the better cycling performance(82.3%capacity retention at $50^{th}$ cycle) than that of the $LiMn_2O_4$(68.3%) prepared by solid state reaction at elevated temperature.