• Journal of the Korean Institute of Telematics and Electronics
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• v.11 no.6
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• pp.1-15
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• 1974

In this paper, the SH mode of elastic surface waves which are used for delay lines of elastic surface wave is the cretically analysed. It is shown that the SH mode has very large electromechanical coupling factor and propagates on the surface with very small decaying coefficient into the medium. In the case of P2T-4, the depth cf piezoelectric medium that contains 80% of energy is 190 wavelengths. An elastic surface wave delay line is discussed from the view point of 2-port network. Center frequency is shifted by the ratio of transducer electrode width to gap between transducer ellcerodes when electromechanical coupling factor is large. Tempera _ore coefficients for bulk waves of LiNbO3 and LiTaO3 are also calculated and the minimum temperature coefficient value of delay time is 5.4X 10-6/$^{\circ}C$ ia the case of transverse wave propagating along Z axis on LiTaO3. Experimental data are in good agreement with theoretical values of the temperature coefficients of delay time for elastic surface waves propagating along X axis of 130$^{\circ}$ and 64$^{\circ}$ rotated Y cut planes of the LiNbO3.

• Korean Journal of Acupuncture
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• v.24 no.2
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• pp.113-127
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• 2007

Objectives : To inform the 5th WHO Informal Consultation meeting on Development of International Standard Acupuncture Point Locations, held in Osaka, Japan, on September $27{\sim}29$, 2005. Results and Conclusions : Nine experts from Korea, China and Japan discussed the principles of acupuncture points locations and the point locations of 33 controversial acupoints that were not agreed at the previous meeting, as well as 328 non-controversial points that all 3 nations agreed on the locations to confirm the expression of every single point. Through this meeting, the locations of ST30, SP12, LR7 and expressions of LU6, LI8, LI9, LI10, LI 13, SP13, BL60, KI3, GB38, LR11, LR12 were agreed. Furthermore, locations of BL39, GB27, GB28 were confirmed out of 6 non-discussed points. However, several points were still required to held additional meeting to discuss. That includes LI19, LI20, ST36, ST37, ST38, ST39, SI6, KI9, PC8, PC9, TE9, TE17, TE23, GB7, GB30, GV26. In addition, foundation for the international society for the acupuncture point location was proposed to make a regular revision of standard acupuncture point location.

• Bulletin of the Korean Chemical Society
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• v.25 no.4
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• pp.480-484
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• 2004

$LiGaO_2$ films have been grown on Si (100) substrates using a new single precursor $[Li(OCH_2CH_2OCH_3)_2-Ga(CH_3)_2]_2$ under high vacuum conditions $(5{\times}10^{-6}Torr)$. The $[Li(OCH_2CH_2OCH_3)_2Ga(CH_3)_2]_2$ was synthe-sized and characterized by using spectroscopic methods and single-crystal X-ray diffraction analysis. The chemical composition, crystalline structure, and morphology of the deposited films were investigated by X-ray photoelectron spectroscopy, X-ray diffraction, and scanning electron microscopy. The results show that polycrystalline $LiGaO_2$ films preferentially oriented in the [010] direction can be deposited on Si (100) at 500-550$^{\circ}C$ by metal organic chemical vapor deposition (MOCVD). The single precursor $[LiOCH_2CH_2OCH_3)_2-Ga(CH_3)_2]_2$ has been found suitable for chemical vapor deposition of $LiGaO_2$ thin films on Si substrates.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.11
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• pp.1049-1054
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• 1998

The LiCo$O_2$ powder was synthesized by a solution phase reaction. This shows a high (003) peak intensity and low (104) or (101) peak intensities in X-ray diffraction spectra. The LiCo$O_2$/Li cell shows an initial discharge capacity of 102.9mAh/g and an average discharge potential or 3.877V at a current density of 50mA/g between 3.0~4.2V. The peaks of dQ/dV plot are associated with Li ion intercalation/deintercalation reaction. To evaluate the cycleability of an actual battery system, cylindrical lithium ion cell was manufactured using graphitized MPCF anode and LiCoO$_2$ cathode. After 100th cycle, this cel maintains 80% capacity of 10th cycle value. The LiCoO$_2$/MPCF cell has a high discharge voltage of 3.6~3.7V and a good cycle life performance on cycling between 4.2~2.7V.

• Journal of Environmental Science International
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• v.5 no.4
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• pp.535-544
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• 1996

In the development of Molten Carbonate Fuel Cell, one of the serious problems is the dissolution of cathode material. Therefore, the development of the alternative cathode which is stable in molten carbonate is needed. In this research, the licoo, was chosen as alternative cathode material. $LiCoO_2$ powder was synthesized by high temperature calcination method and by citrate sol-gel method. And its structure and physical iharacteristics were analyzed by XRD, 1 R, TCA and porosimeter. The conductivity and solubility of $LiCoO_2$ electrode were also measured. Homogeneous $LiCoO_2$ Powder was obtained by citrate sol-Rel method at 445$^{\circ}C$, however, obtained above 75$0^{\circ}C$ by high temperature calcination method. Homogeneous particle size distribution and fine powder were obtained by the citrate sol-Rel method. $LiCoO_2$ electrode showed higher electric conductivity ($1.7 $\Omega$^{-1}cm^{-1}$) than NiO (0.1 $\Omega$^{-9} cm^{-1}) at $650^{\circ}C$. The solubilities of $LiCoO_2$ electrode in electrolyte were varies 0.6 to 1.0 ppm during 200 hours. So, the solubilities of $LiCoO_2$ were much lower than that of NiO.

• Journal of Communications and Networks
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• v.11 no.6
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• pp.626-633
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• 2009

Lawful interception (LI) involves legally accessing private communication such as telephone calls or email messages. Numerous countries have been drafting and enacting laws concerning the LI procedures. With the proliferation of portable Internet services such as the IEEE 802.16e wireless mobile networks, surveillance over illegal users is an emerging technical issue in LI. The evermigrating users and their changing IP's make it harder to provide support for seamless LI procedures on 802.16e networks. Few studies, however, on seamless LI support have been conducted on the 802.16e mobile networks environments. Proposed in this paper are a seamless LI architecture and algorithms for the 802.16e networks. The simulation results demonstrate that the proposed architecture improves recall rates in intercepting mobile user, when compared to the existing LI architectures.

• Journal of the Korean Ceramic Society
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• v.35 no.5
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• pp.451-457
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• 1998

$Li_2$$ZrO_3$ powder which is one of the candidates of breeding materials for the fusion reactor was syn-thesized by a precipitation-combustion process. Although precipitates from the reaction between zirconium nitrate and citric acid were existed in a precursor solution. $Li_2$$ZrO_3$ could easily be obtained by using the mixed fuel of urea and citric acid in stoichiometric composition. The phases of as-synthesized powder con-sisted of $Li_2$$ZrO_3$ and small amounts of $Li_6$$Zr_2O_3$ and $Li_2$$ZrO_3$ The latter phases disappeared after the cal-cination at $1100^{\circ}C$ for 2 h. The primary particle size and the specific surface area of as-synthesized powders were smaller than 20nm and 10-14 $M^2$/g, respectively. The primary particle size of the precipitation-combustion synthesized powders was affected by the size of precipitates present in a precursor solution.

• Journal of Advanced Marine Engineering and Technology
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• v.22 no.6
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• pp.792-799
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• 1998

Further improvement of existing $H_{2}O/LiBr$ absorption refrigeration machine is absolutely neces-sary to promote the utilization of gas-cooling system Among various methods to improve the per-formance of the absorption refrigeration machine this research has focused on the use of a new working fluid that has better properties than the existing $H_{2}O/LiBr$ working fluid. In the series of the research, $H_{2}O/LiBr+HO{(CH_{2})}_{3}OH$ system was selected as the most promisable candidate. The absorption refrigeration machine is water-cooled double-effect, $H_{2}O/LiBr+HO{(CH_{2})}_{3}OH$ sys-tem with series flow type. In this study we found out the characteristic of new working solution through the cycle simulation and compared the result with that of LiBr solution to evaluate. Theoptimum designs and operating conditions were determined based on the operating constraints and the coefficient of performance. Results demonstrate that new working fluid subsrantially increases COP by as much as 10% and has a wider working range with 8% higher crystallization limits compared to the conventional $H_{2}O/LiBr$.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.9
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• pp.930-935
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• 2004

$({Li}_{0.5}0{La}_{0.5}){TiO}_3$ (LLTO) solid electrolyte was grown on LiCo{O}_2 (LCO) cathode films deposited on $Pt/Ti{O}-2/Si{O}_2/Si$ substrate using pulsed laser deposition for all-solid-state lithium microbattery. LLTO solid electrolyte exhibits an amorphous phase at various deposition temperatures. LLTO films deposited at 10$0^{\circ}C$ showed a clear interrace without any chemical reaction with LCO, and showed an initial discharge capacity of 50 $\mu$Ah/cm$^2$-$\mu$m and capacity retention of 90 % after 100 cycles with Li anode in 1mol$ LiCl{O}_4$ in propylene carbonate (PC). The increase of capacity retention in LLTO/LCO structure than LCO itself was attributed to the structural stability of LCO cathode films by the stacked LLTO. The cells of LLTO/LCO with LLTO grown at $100^{\circ}C$ showed a good cyclic property of 63.6 % after 300 cycles. An amorphous LLTO solid electrolyte is possible for application to solid electrolyte for all-solid-state lithium microbattery.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.55-55
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• 2008

이차전지의 음극 중 $LiC_6$는 높은 용량을 보이나 완충하는 프로세스 동안에 금속리튬에 가까운 potential을 갖게 되어 조작에 어려움이 있다. 이러한 대용물질로서 $Li_4Ti_5O_{12}$ spinel은 가볍고 높은 에너지 밀도를 가지고 있고 낮은 전압영역이 가능하여 이차전지의 음극 물질로서 유용하다. 그러나 $Li_4Ti_5O_{12}$ 물질 자체가 insulation이며, 고상합성법을 사용하게 되면 좋은 특성을 나타내기가 어렵다. 이번 실험에서는 고상합성을 통하여 $Ba^{2+}$와 $Sr^{2+}$이온을doping한 후 전기화학적 특성이 어떻게 향상되었는가를 연구하였다. Ba와 Sr을 첨가한 $Li_4Ti_5O_{12}$는 첨가하지 않은 물질에 비하여 보다 안정적인 평탄구역을 갖게 되었으며 방전용량이 $40mAhg^{-1}$의 향상을 가져왔다. 또한 Li half cell에서 100cycle 진행하는 동안 보다 안정적인 전극구조를 유지하였다.