• Nuclear Engineering and Technology
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• v.34 no.1
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• pp.1-8
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• 2002

After kaolin clay was artificially contaminated with Co$^{2+}$ ion, the remediation characteristics were analyzed by the electrokinetic method. Ethanoic buffer was injected in the soil column and $CH_3$COOH was continuously inputted to the cathode reservoir to restrain the pH increase. Since the pH of the cathode side of the soil column was 4.0 initially and increased to only 6.5 after remediation for 43.6 hours, precipitate, Co(OH)$_2$, was not formed in the column. The effluent rate increased with the passage of time and Co$^{2+}$ removal in the column at the initial time were mainly controlled by ion migration. 13.1% of the total amount of Co$^{2+}$ in the soil column was removed in 10 hours, 46.8% of the total Co$^{2+}$ in 20.8 hours, 71.7% of the total Co$^{2+}$ in 30.1 hours, and 94.6% of the total Co$^{2+}$ in 43.6 hours. Meanwhile, residual concentrations in the column calculated by the developed model were similar to those by experiment. experiment.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.28 no.5
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• pp.222-227
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• 2018

$Zn_{1-x}Co_x$ Zeolitic Imidazolate Framework (ZIF) (x = 0~0.05) were prepared by the co-precipitation of $Zn^{2+}$ and $Co^{2+}$ using 2-methylimidazole, which were converted into pure and Co-doped ZnO nanoparticles by heat treatment at $600^{\circ}C$ for 2 h. Homogeneous Zn/Co ZIFs were achieved at x < 0.05 owing to the strong coordination of the imidazole linker to $Zn^{2+}$ and $Co^{2+}$, facilitating atomic-scale doping of Co into ZnO via annealing. By contrast, heterogeneous Zn/Co ZIFs were formed at $x{\geq}0.05$, resulting in the formation of $Co_3O_4$ second phase. To investigate the potential as high-performance gas sensors, the gas sensing characteristics of pure and Co-doped ZnO nanoparticles were evaluated. The sensor using 3 at% Co-doped ZnO exhibited an unprecedentedly high response and selectivity to trimethylamine, whereas pure ZnO nanoparticles did not. The facile, bimetallic ZIF derived synthesis of doped-metal oxide nanoparticles can be used to design high-performance gas sensors.

• The Korean Journal of Pesticide Science
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• v.12 no.1
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• pp.18-23
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• 2008

3D-QSAR on the inhibitory activities of 6-bromobenzo-[4,5]imidazo[$1,2{\alpha}$]-pyridin-8,9-diones analogues as substrate molecule were studied quantitatively using CoMFA and CoMSIA methods. The statistical values of CoMFA model was better predictability and fitness than CoMSIA model. The inhibitory activities according to the optimized CoMFA 2 model were dependent on the steric field (90.4%). From the CoMFA contour maps, it is found that the branched side chain as R-group will be directly attached to the carbon atom (ipso carbon) of substituent, the inhibitory activities had expected to increase. The positive charge favor groups were placed in the position between imidazol ring and pyridine ring, the inhibitory activities would increase. And if the groups of liner type will be substituted, hydrophilic favor group would raise inhibitory activities.

• Journal of the Korean Ceramic Society
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• v.43 no.2 s.285
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• pp.79-84
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• 2006

We studied the microstructure and magnetic property of the pulsed DC magnetron sputtered $Zn_{\0.8}Co_{0.2}O$ film as a function of substrate temperatures. The X-ray patterns of the $Zn_{\0.8}Co_{0.2}O$ film showed a strong (002) preferential orientation at $500^{\circ}C$. The films with a crystallite size of 23-35 nm were grown in the form of nano-sized structure and this tendency was remarkable with increasing substrate temperature. The UV-visible result showed that the $Zn_{\0.8}Co_{0.2}O$ film prepared above $300^{\circ}C$ has a high optical transmittance of over $80\%$ in the visible region. The absorption bands were observed due to sp-d interchange action by $Co^{2+}$ complex ion and dd transition in the region from 500 to 700nm. The resistivity of the film was below $10^{-1}\;\Omega-cm\;above\;300^{\circ}C$. The AGM analysis results for the all films showed the magnetic hysteresis curves of ferromagnetic nature. The low electrical resistivity and room temperature ferromagnetism of ZnCoO thin films 'deposited above $300^{\circ}C$ suggested the possibility for the application to Diluted Magnetic Semiconductors (DMSs).

• Textile Coloration and Finishing
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• v.8 no.1
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• pp.1-7
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• 1996

In discharge printing of cotton fabrics dyed with C.I. Reactive Orange 16(O-16), C.I. Reactive Blue 19(B-19) and C.I. Reactive Black 5(Bl-5), when the dyes were discharged by some chemicals, such as $K_{2}CO_{3}$, BASB, DSR, sarcosine and GSB, the single use of those chemicals made a very poor discharge, but mixing them with $K_{2}CO_{3}$ resulted to the outstanding improvement of discharge. Especially the dischargeability of $K_{2}CO_{3}$ BASB or $K_{2}CO_{3}$+DSR was very gratifying. For O―16, $K_{2}CO_{3}$+ DSR was slightly more effective than $K_{2}$CO$_{3}$+BASB, but for B―19 and Bl―5 $K_{2}CO_{3}$+BASB and $K_{2}CO_{3}$+DSR showed similar good results. In discharging of O―16 and B―19 by $K_{2}CO_{3}$+BASB or $K_{2}CO_{3}$ +DSR, the dischargeabilities of them increased as the time of 102$^{\circ}C$ steaming increased under the condition of 102$^{\circ}C$ steaming and no baking, but not under the condition of 102$^{\circ}C$ steaming and 16$0^{\circ}C$ baking. However for Bl-5, without regard to baking, the 102$^{\circ}C$ steaming of more than 15 minutes caused the discharge to be much more remarkable than that of 8 minutes did. Generally baking elevated the dischargeability, and this was sure in discharging by $K_{2}CO_{3}$+BASB or $K_{2}CO_{3}$+DSR. And it was confirmed that the structure of vinylsulfonyl reactive dyes could effect on the dischargeability because the three dyes, though little, showed different discharge behaviors.

• Korean Chemical Engineering Research
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• v.58 no.1
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• pp.52-58
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• 2020

Electrochemical characterization and thermal stability were investigated for MgF₂ coated LiNi_0.8Co_0.15Al_0.05O₂ cathode. The ratio of MgF₂ was controlled by 0.5, 1, 3 wt%. Cyclic voltammetry, charge-discharge profiles, rate capability, cycle life were measured for electrochemical properties. DSC analysis was measured for thermal stability. The first discharge capacities of MgF₂ coated LiNi_0.8Co_0.15Al_0.05O₂ were decreased at 0.1C-rate compared to pristine LiNi_0.8Co_0.15Al_0.05O₂. But the rate capability and cycle life of MgF₂ coated LiNi_0.8Co_0.15Al_0.05O₂ were improved at 2C-rate. In DSC analysis result, the exothermic temperature of MgF₂ coated LiNi_0.8Co_0.15Al_0.05O₂ was increased and peak height was decreased.

• Korean Journal of Materials Research
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• v.11 no.8
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• pp.713-717
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• 2001

The magnetic and magnetostrictive properties of amorphous Tb/sub 45.7/Fe/sub 54.3-x/Co/sub x/ and Tb/sub 50.2/Fe/sub 49.8-x/Co/sub x/ (0≤x≤9.6) thin films have systematically been investigated. The films were fabricated by rf magnetron sputtering using a composite target which consists of a Fe plate and Tb, Co chips. The microstructure mainly consists of an amorphous phase. Excellent intrinsic and low magnetic-field-magnetostrictive properties were achieved in Tb/sub 45.7/Fe/sub 54.3-x/Co/sub x/ and Tb/sub 50.2/Fe/sub 49.8-x/Co/sub x/ (0≤x≤9.6). The magnetostriction of 130 ppm was obtained with low field of 100 Oe. The intrinsic magnetostriction(applied field, 5 kOe) were increased from 330ppm to 400ppm.

• Atmosphere
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• v.25 no.1
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• pp.85-97
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• 2015

This study is to investigate future changes in carbon cycle using the HadGEM2-Carbon Cycle simulations driven by $CO_2$ emissions. For experiment, global carbon budget is integrated from the two (8.5/2.6) representative concentration pathways (RCPs) for the period of 1860~2100 by Hadley Centre Global Environmental Model, version 2, Carbon Cycle (Had-GEM2-CC). From 1985 to 2005, total cumulative $CO_2$ amount of anthropogenic emission prescribed as 156 GtC. The amount matches to the observed estimates (CDIAC) over the same period (136 GtC). As $CO_2$ emissions into the atmosphere increase, the similar increasing tendency is found in the simulated atmospheric $CO_2$ concentration and temperature. Atmospheric $CO_2$ concentration in the simulation is projected to be 430 ppm for RCP 2.6 at the end of the twenty-first century and as high as 931 ppm for RCP 8.5. Simulated global mean temperature is expected to rise by $1.6^{\circ}C$ and $3.5^{\circ}C$ for RCP 2.6 and 8.5, respectively. Land and ocean carbon uptakes also increase in proportion to the $CO_2$ emissions of RCPs. The fractions of the amount of $CO_2$ stored in atmosphere, land, and ocean are different in RCP 8.5 and 2.6. Further study is needed for reducing the simulation uncertainty based on multiple model simulations.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.04a
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• pp.57-57
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• 1994

졸-겔 침지코팅 (dipcoating) 또는 가압 졸-겔 코팅 (pressurized coating) 법으로 제조한 $\gamma-Al_2O_3, SiO_2, TiO_2$ 및 aluminosilicate 복합막에 대하여 $CO_2$, He, $N_2$, 및 $O_2$ 기체 투과율과 $CO_2$ 분리계수를 측정하였다. 이들 막을 통한 모든 기체의 이동은 Knudsen 유동이 지배적이었으며 $CO_2/N_2$의 분리계수는 0.9 ~ 1.1 정도로 Knudsen 분리계수 ($CO_2/N_2$의 경우 0.8)보다 약간 높은 값을 보여주었다. $CO_2$ 분리계수를 향상시키기 위하여 silane coupling 및 산화물 도핑법에 의한 복합막의 표면개질을 시도하였으며 분리막의 재질 및 표면개질 조건에 따른 $CO_2/N_2$ 분리계수 변화를 측정 비교하였다. Silane coupling에 의한 표면개질이 $CO_2$의 표면 친화성 (affinity)에 의한 표면확산속도를 증가시키기 때문에 $CO_2$ 분리에 있어서 산화물 도핑에 의한 표면개질보다 더욱 효과적이었다.

• Bulletin of the Korean Chemical Society
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• v.15 no.8
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• pp.616-622
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• 1994

The oxidation of carbon monoxide by gaseous oxygen in the presence of a powdered $Nd_{1-x}Sr_xCoO_{3-y}$ solid solution as a catalyst has been investigated in the temperature range from 150$^{\circ}$C to 300$^{\circ}$C under various CO and $O_2$ partial pressures. The site of Sr substitution, nonstoichiometry, structure, and microstructure were studied by means of powder X-ray diffraction and infrared spectroscopy. The electrical conductivity of the solid solution has been measured at 300$^{\circ}$C under various CO and $O_2$ partial pressures. The oxidation rates have been correlated with 1.5-and 1.2-order kinetics with and without a $CO_2$ trap, respectively; first-and 0.7 order with respect to CO and 0.5-order to $O_2$. For the above reaction temperature range, the activation energy is in the range from 0.25 to 0.35 eV/mol. From the infrared spectroscopic, conductivity and kinetic data, CO appears essentially to be adsorbed on the lattice oxygens of the catalyst, while $O_2$ adsorbs as ions on the oxygen vacancies formed by Sr substitution. The oxygen vacancy mechanism of the CO oxidation and the main defect of $Nd_{1-x}Sr_xCoO_{3-y}$ solid solution are supported and suggested from the agreement between IR data, conductivities, and kinetic data.