• Journal of the Korean Ceramic Society
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• v.42 no.3 s.274
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• pp.211-217
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• 2005

[ $Zn_{1-x}Co_{x}O$ (x=0-0.3) films were grown on Corning 7059 glasses by asymmetrical bipolar pulsed dc magnetron sputtering. The c-axis orientation along (002) plane was enhanced with increasing Co concentration. The $Zn_{1-x}Co_{x}O$ films are grown with fibrous grains of tight dome shape. The transmittance spectra measured from UV-visible showed that sp-d exchange interactions and typical d-d transitions become activated with increasing Co concentration. The electrical resistivity of $Zn_{1-x}Co_{x}O$ films increased with increasing Co concentration, especially it increased greatly at $30at\% Co. X-ray photoelectron spectroscopy and alternating gradient magnetometer analyses indicated that no Co metal cluster is formed and the ferromagnetic properties are exhibited. The low electrical resistivity and room temperature ferromagnetism of $Zn_{1-x}Co_{x}O$ thin films suggested the possibility of the application to Diluted Magnetic Semiconductors (DMSs).

• Journal of the Korean Chemical Society
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• v.37 no.1
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• pp.55-61
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• 1993

An application of the optoacoustic detection method to investigate the catalytic effect of a perovskite, $Gd_{1-x}Sr_xCoO_{3-y}$ (x = 0.00, 0.25, 0.50, 0.75) system, in the oxidation reaction of CO is described. The optoacoustic signals Of $CO_2$ produced from the oxidation reaction were measured for differing x values in $Gd_{1-x}Sr_xCoO_{3-y}$. By monitoring optoacoustic signals with respect to the time, the concentration ratios of CO and $O_2$, and the temperature, the kinetic information on the catalytic properties of the perovskite for CO oxidation reaction can be obtained. The effect of Sr substitution in $Gd_{1-x}Sr_xCoO_{3-y}$ has been found to show the maximum catalytic effect at x = 0.25 and the substantial increase in catalytic activity at temperatures above 200$^{\circ}C$. It demonstrates that the optoacoustic detection method allows the investigation of the integrated catalytic effect not only for the oxidation reaction of CO, but also for many reactions, in general, by continuously and directly detecting the species associated with the reactions.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.325-328
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• 2002

We developed a high performance 2.2" active matrix OLED display for IMT-2000 mobile phone. Scan and Data driver circuits were integrated on the glass substrate, using low temperature poly-Si(LTPS) TFT CMOS technology. High efficiency EL materials were employed to the panel for low power consumption. Peak luminescence of the panel was higher than 250cd/$m^2$ with power consumption of 200mW.

• Korean Journal of Environment and Ecology
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• v.26 no.5
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• pp.780-786
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• 2012

A trenching method was used to determine the contribution of root respiration to soil respiration in Quercus acutissima forest in the vicinity of Gongju, Chungnam Province, Korea. $CO_2$ efflux in soil respiration plot($R_{control}$, $R_c$) and microblal respiration plot($R_{trenched}$, $R_t$) in Q. acutissima forest were measured from June 2011 to May 2012 by using IRGA soil respiration analyzer. Seasonal $CO_2$ efflux in $R_c$ and $R_t$ were higher in summer season than in winter season. In August, maximun $CO_2$ efflux in $R_c$ and $R_t$ was 1.345 and 0.897 g $CO_2\;m^{-2}\;hr^{-1}$, respectively. $CO_2$ efflux in $R_t$ was lower by 33.31% than that in $R_c$(P<0.05). In January, $CO_2$ efflux in $R_c$ and $R_t$ was 0.097 and 0.032g $CO_2\;m^{-2}\;hr^{-1}$, respectively. $CO_2$ efflux in $R_t$ was lower by 67.01% than that in $R_c$(P<0.01). The amount of annual $CO_2$ efflux from $R_c$ and $R_t$ was 4.320, 2.834kg $CO_2\;m^{-2}\;yr^{-1}$, respectively. There was a significant correlations between soil temperatures and soil respiration. Contribution of root respiration to total soil respiration in this Q. acutissima forest was 34.40%.

• Journal of the Korean Ceramic Society
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• v.13 no.4
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• pp.5-8
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• 1976

Both oriented and non-oriented ferroxplana $Co_{1-x}Zn_xZ(Ba_3Co_{2(1-x)}Zn_{2x} Fe_{24}O_{41})$ with x=0.00, 0.45 were prepared by conventional ceramic method. The magnetostrictions of thus prepared specimens were measured by use of the three terminal capacitor device at room temperature. The magnitude of measured values was approximately five times greater than that of ZnY ferroxplana. The easy-magnetization plane at room temperature of both CoZ and Co0.55 $Zn_{0.45}$Z was their basal plane. The magentostrictions in the basal plane and the other planes showed saturated values at magnetic field intensity of about 2Koe and 4Koe, respectively. The magnetostriction constants $K_1, \; K_2, \;K_3\; and\; K_4$ for CoZ were -2.4, -10.5, -5.9 and -45.2$\times10^{-6}$ , while those for $Co_{0.55}Zn_{0.45}Z$ were +0.1, -1.2, -6.3 and -39.0$\times$10^{-6}, , respectively.

• Applied Chemistry for Engineering
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• v.1 no.2
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• pp.207-214
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• 1990

The catalytic reaction between CO and NO on polycrystalline Pt surface, which is very important in the development of catalyst for automobile exhaust gas control, has been studied using thermal desorption spectrometry(TDS) and steady-state experiment under ultra-high vacuum(UHV) conditions. With the pressures of CO and NO of each $1{\times}10^{-7}Torr$, the $CO_2$ formation rate showed a maximum at 560K. At the reaction temperature of 560K and the NO pressure of $1{\times}10^{-7}Torr$, the production of $CO_2$ was first order in $CO_2$ was first order in CO pressure below $1.35{\times}10^{-7}Torr$ of CO pressure whereas at higher CO pressures the rate became minus 0.3 order in CO. But the efforts of reactant pressure on the reaction was understood in consideration of the surface concentrations of adsorbates. With the results, we proposed a new reaction mechanism for this reaction.

• Korean Journal of Materials Research
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• v.4 no.3
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• pp.301-311
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• 1994

The growth of amorphous and first crystalline phase, and phase sequence by solid state reaction were examined in Co/Si multilayer thin films by DSC and XRD. The experimental results were compared with the results expected by effective driving force models, PDF and effective heat of formation models.Amorphous phase growth was not observed in Co/Si system and it was consistent with the predicted result by effective driving force. It was observed that the first crystalline phase is CoSi. According to the PDF and effective heat of formation models, the first crystalline phases were CoSi and $CO_2Si$, respectively. The experiemental results were coincident with the PDF model considering structure factors. In case of the atomic concentration ratios of 2Co : 1Si and 1Co : 2Si, the phases sequences were $CoSi\to Co_2Si$ and $CoSi \to Co_2Si \to CoSi \to CoSi_2$, respectively and it was analysized through the effective heat of formation model. The formations of CoSi, $CO_2Si$ and $COSi_2$ in initial stage were controlled by nucleation and the activation energies for the nucleation of three phases were 1.71, 2.34 and 2.79eV.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.3
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• pp.185-191
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• 2014

In this paper, absorption and reaction characteristics of low $CO_2$ and alkanolamines were investigated. As MEA concentrations increase 1, 2 and 3 wt%, $CO_2$ loadings decrease 0.34 mol-$CO_2/mol$-absorbent, 0.32 mol-$CO_2/mol$-absorbent and 0.3 mol-$CO_2/mol$-absorbent, respectively. Also, $CO_2$ loadings decrease from 0.32 mol-$CO_2/mol$-absorbent, 0.30 mol-$CO_2/mol$-absorbent and 0.28 mol-$CO_2/mol$-absorbent as AMP concentrations increase 1, 2 and 3 wt%. Experimental results with blending solutions show that $CO_2$ loading was the highest, 0.52 mol-$CO_2/mol$-absorbent, when 0.5 wt% MEA and 0.5 wt% AMP were blended.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1996.05a
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• pp.228-231
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• 1996

We prepared $LiCo_{1-x}Ni_{x}O_2$ by reacting stoichiometric mixture of LiOH.$H_2O$, $CoCO_3$.$xH_2O$ and $Ni(OH)_2$ (mole ratio respectively) and heating at $850^{\circ}C$ for 5h. We awared through XRD that from 0 to 0.5 at x in $LiCo_{1-x}Ni_{x}O_2$ is well formed for hexagonal structure, but the more $LiCo_{1-x}Ni_{x}O_2$ involve NI, the more hexagonal structure is not well formed. In the result of charge/discharge test, charge/discharge characteristic of $LiCo_{1-x}Ni_{x}O_2$ is similar to that of $LiCoO_2$. Therefore, $LiCo_{1-x}Ni_{x}O_2$ is superior to $LiCoO_2$ for Li secondary battery

• Journal of the Korean Ceramic Society
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• v.38 no.6
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• pp.515-521
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• 2001

출발 물질로서 L $i_2$C $O_3$, NiC $O_3$, CoC $O_3$를 사용하고 조성과 합성 온도를 변화시켜, 고온 고상법에 의하여 LiN $i_{1-y}$ $Co_{y}$ $O_2$(y=0.1, 0.3, 0.5)를 합성하였다. 합성과 시료들의 결정구조, 미세구조 그리고 전기화학적 특성을 조사하였다. 80$0^{\circ}C$와 8$50^{\circ}C$에서 제조한 L $i_{x}$N $i_{1-y}$ $Co_{y}$ $O_2$는, 삼방정계(space group: R3m)의 $\alpha$-NaFe $O_2$구조로 결정화되어 있는 층상 구조를 형성하였다. LiN $i_{1-y}$ $Co_{y}$ $O_2$(y=0.1, 0.3, 0.5)는 Co의 양이 증가함에 따라 a축과 c축의 크기가 감소하였는데, 이는 코발트 이온의 크기가 니켈 이온의 크기보다 작은데 기인하는 것이다. 그러나 c축과 a축의 크기의 비(c/a)가 증가하였음은 이차원적 구조가 잘 발달됨을 보여준다. 니켈에 대한 코발트의 치환량에 따른 리튬 이온의 삽입/추출 가역성은 코발트의 치환량이 증가하면서 증가하여 y=0.3인 LiN $i_{0.9}$ $Co_{0.1}$ $O_2$에서 대체로 우수하였고 그 이상으로 y값이 증가하면 가역성이 나빠졌다. 80$0^{\circ}C$에서 합성한 LiN $i_{0.9}$ $Co_{0.1}$ $O_2$가 가장 큰 초기 방전 용량 146 mAh/g을 나타내었으며, 싸이클링 성능도 비교적 우수하였다. 8$50^{\circ}C$에서 합성한 LiN $i_{0.9}$ $Co_{0.1}$ $O_2$와 LiN $i_{0.7}$ $Co_{0.3}$ $O_2$가 우수한 싸이클링 성능을 보였다.다. 싸이클링 성능을 보였다.다.보였다.다.