• Journal of the Korean Chemical Society
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• v.19 no.6
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• pp.414-419
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• 1975

The insoluble tungsten complexes with 8-hydroxy quinoline (oxine=Hox), aniline (A), and pyridine(Py) in several organic solvents have been synthesized. Using the different solvents with oxine, two different complexes have been synthesized in dichloromethane and dimethylformamide(DMF), respectively. Only one kind of complex has been synthesized with aniline in dichloromethane and with pyridine in acetone. The complexes may be formulated as $WCl_2(Hox)_2,\;[WO_2(Ox_2)],\;[WCl_3A_3],\;and\;[WO_2ClPy]$ by the results of elemental analysis, infrared spectral data, and thermogravimetric analysis.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.6
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• pp.51-60
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• 2011

Researches on indoor localization using the wireless sensor network have been actively carried out to be used for indoor area where GPS signal is not received. Computationally efficient WCL(Weighted Centroid Localization) algorithm is shown to perform relatively well. However, to get the best performance for WCL all the anchor nodes must send signal with power to cover 96% of the network. The fact that outside the transmission range of the fixed nodes drastic localization error occurs results in large mean error and deviation. Due to these problems the WCL algorithm is not easily applied for use in the real indoor environment. In this paper we propose SRS(Succesive Region Setting) algorithm which sequentially reduces the estimated location area using the signal strength from the anchor nodes. The proposed algorithm does not show significant performance degradation corresponding to transmission range of the anchor nodes. Simulation results show that the proposed SRS algorithm has mean localization error 5 times lower than that of the WCL under free space propagation environment.

• Polymer(Korea)
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• v.30 no.4
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• pp.311-317
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• 2006

Poly-DCPD and poly-DCPD/silicates hybrids were prepared by in-situ ROMP poly-merization using $WCl_6$ catalyst. Good dispersion of silicates in DCPD medium can be accomplished by sonication method. Compared with nanocomposites prepared using $Na^+MMT$, the nanocomposites with CL 15A showed well dispersed silicate's morphology. superior thermal and mechanical properties. Additionally, well dispersed silicates in DCPD matrix enhanced the gas barrier property of the nanocomposites.

• Bulletin of the Korean Chemical Society
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• v.12 no.5
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• pp.460-461
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• 1991

• Bulletin of the Korean Chemical Society
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• v.18 no.1
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• pp.66-70
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• 1997

The polymerization of 4, 4-bis(acetoxymethyl)-1, 6-heptadiyne (BAH) was carried out by MoCl5 and WCl6 with various organometallic cocatalysts. MoCl5-based catalysts were more effective than WCl6-based ones for the cyclopolymerization of BAH. Poly(BAH) was characterized to have polymer backbone with conjugated double bond and cyclic structure by IR, UV-visible, and 1H-and 13C NMR spectroscopies. The polymer was stable up to 310 ℃ and 5 % weight loss show up at 350 ℃. The resulting dark violet polymer exhibited good solubility in common organic solvents and could be cast on a glass plate to give film with good mechanical properties. It was found that oxygen permeability (PO2) and permselectivity (PO2/PN2) of the resulting polymer were 15.2 barrer and 2.84, respectively.

• Bulletin of the Korean Chemical Society
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• v.29 no.5
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• pp.909-910
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• 2008

• Proceedings of the Korean Information Science Society Conference
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• 2011.06d
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• pp.167-170
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• 2011

많은 측위 알고리즘이 참조노드가 정사각형의 모서리에 위치한다고 가정 하고 있지만, 실제로는 다각형이 되거나 매쉬형으로 배치될 수 있다. 신호세기를 달리함으로써 동심원을 구성하여 측위하는 WMRL(Weighted Multiple Rings Localization)도 기본적으로 참조노드의 배치가 정사각형으로 가정하고 있다. 본 논문에서는 참조노드는 임의로 배치되어 있는 경우에서의 측위로 확장한다. 즉, 측위하는 센서 노드가 수신 가능한 전파를 송신하는 모든 참조노드로부터 링 번호를 기반으로 자신의 위치를 추청한다. WMRL의 다중 신호 세기 링 방식을 채용, 각 링의 도달거리를 기반으로 센서노드가 자신과 참조노드 간의 거리를 유추하고, 최소자승법을 이용해 자신의 좌표를 계산하는 알고리즘을 제안한다. 실험 결과 제안한 알고리즘은 에러가 없는 환경과 다수 참조노드 환경에서 WMRL 및 WCL(Weighted Centroid Localization)보다 2배 이상의 성능향상을 보였으며, 에러가 있는 전파환경에서는 DV-hop 보다 평균 6%, WCL 및 WMRL에는 평균 16% 정도의 성능 향상 결과를 보였다.

• Economic and Environmental Geology
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• v.47 no.3
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• pp.227-235
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• 2014

For technology level assessment of KIGAM World Class Laboratories (WCL) candidates, bibliometric and qualitative analysis was conducted on their research papers listed on the SCIE database during 2009-2012. For the six research areas of geoscience and mineral resources, a research excellence indicator was applied using a Modified Rank Normalized Impact Factor (mrnIF), which was introduced by Heo et al. (2008) and Cho (2013). The KIGAM research department in rare metals utilization had the highest score for Impact Factor (IF) per paper in 2012 but the groundwater department or the exploration geophysics department came first based on the position and the mrnIF. Applying the mrnIF, the KIGAM research department in groundwater achieved excellent results in 2009 and 2011 and the urban mine department or exploration geophysics department came first place in other years. In the groundwater area, the percentage of research papers over 80 or 90 mrnIF, using Cho (2013)'s research excellence index, was the highest in 2011. The Cho (2013)'s excellent research indicator, 20%, the ratio of over 90 mrnIF was matched in the urban mining area for the whole research period, 2009-2012, and in the groundwater area for several years except 2010. Qualitative analysis of research papers can show the technology level of research departments. KIGAM World Class Laboratories (WCL) candidates should focus on increasing the quality and the quantity of their research papers.

• Bulletin of the Korean Chemical Society
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• v.32 no.8
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• pp.2737-2742
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• 2011

Ring-opening metathesis polymerization (ROMP) of an ethyl-substituted tetracyclododecene (8-ethyltetracyclo[$4.4.0.1^{2,5}.1^{7,10}$] dodec-3-ene, Et-TCD) was carried out in the presence of a ternary catalyst system consisting of $WCl_6$, triisobutyl aluminium (iso$Bu_3Al$), and ethanol. The optimal molar ratio of Et-TCD/$WCl_3$/iso-$Bu_3Al$/ethanol was found as 500/1/3/2 at which the yield of ring-opened polymer was 100%. 1-Hexene was shown to be an effective molecular weight controlling agent for ROMP reaction of Et-TCD. The hydrogenation of the ring opened polymer (p-Et-TCD) was conducted successfully using Pd(5 wt %)/${\gamma}$-$Al_2O_3$ at $80^{\circ}C$ for 1 h. Chemical structures of p-Et-TCD and its hydrogenated product($H_2$-p-Et-TCD) were characterized using 2D NMR techniques ($^1H-^1H$ COSY and $^1H-^{13}C$ HSQC). The changes of physical properties such as thermal stability, glass transition temperature and light transmittance after the hydrogenation were also investigated using TGA, DSC, and UV.

• Bulletin of the Korean Chemical Society
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• v.14 no.6
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• pp.708-712
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• 1993

The Polymerization of p-chlorophenyl propargyl ether (CPE) was carried out using various transition metal catalysts. The catalytic activity of $MoCl_{5}$-based catalysts was greater than that of $WCl_6$-based catalysts. $MoCl_5$ alone and $MoCl_{5}$-cocatalyst systems polymerized CPE very effectively to give a high yield of poly(CPE). In most cases, the polymer yield was quantitative and the average molecular weight $({\bar{M}}n)$ was in the range of 9,000 and 17,000. The NMR, IR, UV-visible spectra indicated that the present poly(CPE) has a linear conjugated polyene structure having p-chlorophenyl oxymethylene substituent. The poly(CPE) was mostly dark-brown colored powder and was completely soluble in various organic solvents such as chloroform, methylene chloride, THF, chlorobenzene, etc. The X-ray diffraction analysis indicated that the present poly(CPE) is amorphous.