• Bulletin of the Korean Chemical Society
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• v.19 no.4
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• pp.457-462
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• 1998

A chiral pentadentate bis-amide ligand, 1,9-bis(S)-pyrrolidinyl-2,5,8-triazanonane-1,9-dio ne$(S,S-prodienH_2)$ has been synthesized from the reaction of bis(2-aminoethyl)amine(dien) and S-proline, and the structure of $[Co(S,S-prodien)H_2O]ClO_4$ has be en determined by single crystal X-ray diffraction. The geometrical structure of the Co(III) complex has been an αβ -form, where the dien moiety of ligand chelates to a facial in metal center, and the aqua ligand coordinates a cis site to the secondary nitrogen of dien. The Co-N(1), Co-N(3) distances of two amide moiety in S,S-prodien are shorter than the other Co-N(2), Co-N(4), and Co-N(5) distances because of the increased basicity of nitrogen in amide. The complex crystallizes in the monoclinic space group $P2_1$(#4), with a=7.838(1), b=12.675(1), c=9.710(1) Å, β=100.39(1) and z=2. Refinement gives the final R and $R_w$ values of 0.045 and 0.057, respectively for 2130 observed reflections. Based upon the CD and X-ray data, it is identified that the absolute configuration of the αβ -$[Co(S,S-prodien)H_2O]ClO_4$ has a Λ-form.

• The Journal of Natural Sciences
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• v.4
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• pp.85-93
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• 1991

In solid reaction of the eqimolecular mixture of $BaCO_3$ and $TiO_2$, $CO_2$ generates by the following reaction ; $BaCO_3 + TiO_2\longrightarrow$ $BaTiO_3 + CO_2$ The solid reaction is studied as the kinetics of decomposition reaction with DTA-TG. The results are as follows. 1. $BaCO_3$ with is coexisted with $TiO_2$ decompose at lower temperature than pure $BaCO_3$. The reason is decreasing free eneragy of products. 2. Carter's equation is more important than Jander's equation in solid reaction of $BaCO_3$ decomposi-tion. The activation energy obtained by Carte r's equation is 42.8 Kcal/mol.

• Elastomers and Composites
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• v.51 no.1
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• pp.49-55
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• 2016

Nanosized cobalt disulfide ($CoS_2$) particles were synthesized with 0.08 M cobalt chloride hexahydrate ($CoCl_2{\cdot}6H_2O$) and 0.2 M sodium thiosulfate pentahydrate ($Na_2S_2O_3{\cdot}5H_2O$) dissolved in distilled water under microwave irradiation. $[C_{60}]Fullerene-CoS_2$ nanocomposites were prepared with nanosized $CoS_2$ particles and [$C_{60}$]fullerene as heated by $700^{\circ}C$ for 2 h in an electric furnace. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) identified the heated $[C_{60}]fullerene-CoS_2$ nanocomposites. Heated $[C_{60}]fullerene-CoS_2$ nanocomposites were investigated the activity of photocatalytic degradation as a catalyst in various organic dyes like acid yellow 23, methylene blue, methyl orange, and rhodamine B with ultraviolet light at 254 nm by UV-vis spectrophotometer.

• 한국초전도학회:학술대회논문집
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• 2007.07a
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• pp.6-6
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• 2007

• Knowledge Management Research
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• v.1 no.1
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• pp.127-137
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• 2000

Effective knowledge sharing and creating requires human networking as well as system. Corporation 'S' organized 'community of practice(CoP),' which is a virtual group based on work process, skill, and interest. The purpose of this study is to suggest effective CoP establishment and implementation methods, based upon 'S' experience. The effective methods this study suggests are : setting up clear CoP objectives by each CoP; dual CoP system with career centered and subject centered; alignment with business strategy; guide by knowledge integrator, and professional competence development as CoP purpose. Key success factors to CoP activities also include effective communication, facilitators' competency, and managers' support.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.10a
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• pp.582-583
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• 2005

• Proceedings of the PSK Conference
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• 2000.04a
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• pp.182.1-182.1
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• 2000

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.98.3-98
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• 1998

• Journal of the Korean Magnetics Society
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• v.17 no.3
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• pp.124-127
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• 2007

Magnetic tunnel junctions (MTJs), which consisted of amorphous CoFeSiB layers, were investigated. The CoFeSiB layers were used to substitute for the traditionally used CoFe and/or NiFe layers with an emphasis given on understanding the effect of the amorphous free layer on the switching characteristics of the MTJs. CoFeSiB has a lower saturation magnetization ($M_s\;:\;560\;emu/cm^3$) and a higher anisotropy constant ($K_u\;:\;2800\;erg/cm^3$) than CoFe and NiFe, respectively. An exchange coupling energy ($J_{ex}$) of $-0.003\;erg/cm^2$ was observed by inserting a 1.0 nm Ru layer in between CoFeSiB layers. In the Si/$SiO_2$/Ta 45/Ru 9.5/IrMn 10/CoFe 7/$AlO_x$/CoFeSiB 7 or CoFeSiB (t)/Ru 1.0/CoFeSiB (7-t)/Ru 60 (in nm) MTJs structure, it was found that the size dependence of the switching field originated in the lower $J_{ex}$ using the experimental and simulation results. The CoFeSiB synthetic antiferromagnet structures were proved to be beneficial for the switching characteristics such as reducing the coercivity ($H_c$) and increasing the sensitivity in micrometer size, even in submicrometer sized elements.

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.08a
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• pp.77.2-77
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• 1998