• Transactions on Electrical and Electronic Materials
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• v.2 no.1
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• pp.27-31
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• 2001

$\beta$-$In_2S_3$ and $\beta$-$In_2S_3$:$Co^{2+}$ thin films were grown using the spray pyrolysis method. The thin films crystallized into tetragonal structures. The indirect energy band gap of the thin films was found to be 2.32 eV for $\beta$-$In_2S_3$ and 1.81 eV for $\beta$-$In_2S_3$:$Co^{2+}$(Co:1.0 mol%) at 198K. The direct energy band gap was found to be 2.67 eV for $\beta$-$In_2S_3$ and 2.17 eV for $\beta$-$In_2S_3$:$Co^{2+}$(Co:1.0 mol%). Impurity optical absorption peaks were observed for the ${\beta}$-$In_2S_3$:$Co^{2+}$ thin films. These impurity absorption peaks are assigned, based on the crystal field theory, to the electron transitions between the energy levels of the $Co^{2+}$ ion sited in $T_{d}$ symmetry.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.42-46
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• 2000

${\beta}{\cdot}In_2S_3$ 및 ${\beta}{\cdot}In_2S_3:Co^{2+}$ 은 $In_2S_3$+S+ZnS를 출발물질로 하여 ($ZnCl_2+I_2$)를 수송매체로 사용한 chemical transport reaction method로 성장시켰다. 성장된 단결정은 tetragonal structure를 갖고 298K에서 indirect optical energy gap은 2.240eV, 1.814eV로 각각 주어졌고, direct optical energy gap은 2.639eV, 2.175eV로 각각 주어졌다. ${\beta}{\cdot}In_2S_3:Co^{2+}$ single crystal에서 impurity optical absorption peak가 나타났으며, 이들 peaks의 origin은 $Co^{2+}(Td)$ ion의 energy level 간의 electron transition임을 crystal field theory를 적용하여 규명하였다.

• Journal of the Korean Vacuum Society
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• v.5 no.3
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• pp.213-217
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• 1996

HgS and HgS: Co crystals and films grown by the slow cooling and the chemical bath deposition method were used to measure their crystal structure and their optical absorption spectra. HgS and HgS: Co crystals are hexagonal structure with the lattice constant $a_0=4.155{\AA}$, $c_0=9.505{\AA}$ for HgS and $a_0=4.148{\AA}$, $c_0=9.462{\AA}$ for HgS and $a_0=4.135{\AA}$, $c_0=9.442{\AA}$ for HgS: Co, respectively. The optical energy gap of these crystals are given as 2.040 eV for HgS and 1.900 eV for HgS: Co, and the optical energy gap of these films were 2.440 eV for HgS and 1.940 eV for HgS: Co at room temperature, respectively.

• KSBB Journal
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• v.11 no.3
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• pp.295-302
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• 1996

The measurements of rubisco parameters are important in photosynthetic studies. In this experiment, we used photometric assay method to detect these major parameters, such as activity, carbamylation and amount of rubisco. The main advantages of this method are very simple and as sensitive as conventional methods which usually produce radioactive waste. In this study, with kidney bean (Phaseolus vulgatis L.) leaves grown at normal $CO_2$ (350ppm) and high $CO_2$ (650 ppm), we investigated the effect of $CO_2$ concentration on activation and carbamylation of rubisco by measuring the rubisco activity, carbamylation rate and amount of rubisco using a dual beam (334nm and 405nm) spectrophotometer, and analyzed the polypeptide profiles of rubisco by SDS-PAGE. When $CO_2$ concentration was raised from 350ppm to 650ppm, all parameters of rubisco were decreased : $41.2{\mu}M/m^2/s and 52.2{\mu}M/m^2/s$ to $27.4{\mu}M/m^2/s and 46.1{\mu}M/m^2/s$ for initial and total rubisco activity, respectively ; from 79% to 58.9% for carbamylation rate ; from $1.94 {\mu}M/m^2$ to 1.58{\mu}M/m^2$ for amount of rubisco. These results suggests that the decrease in rubisco activity at high $CO_2$ was caused by carbamylation. The analysis of the preparation by SDS-PAGE showed two major polypeptides at 50 and 14.5 kD which were identified as the large and the small subunits of rubisco. There were no differences in the intensity compared high $CO_2$ to normal $CO_2$ in both 50 kD and 14.5 kD bands. We also found that these inhibitory effects of $CO_2$ were reversible. When high $CO_2$ was switched to normal $CO_2$, the parameters of rubisco changed were almost the same as normal rubisco parameters. These data provide an evidence that activity of rubisco was recovered by $CO_2$ concentration of 350 ppm.

• Journal of the Korean Ceramic Society
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• v.54 no.4
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• pp.308-313
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• 2017

In this study we examined the photo-degradation efficiency of $CoS_2-G-TiO_2$ nanocomposites under visible light irritation using Reactive Black B (RBB) as standard dye, $CoS_2-G-TiO_2$ nanocomposites synthesized by facial microwave assist technique, and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopic analysis. Our results show the efficiency of the $CoS_2-G-TiO_2$ ternary nanocomposite is better than $CoS_2-G$ and $TiO_2-G$ nanocomposite. The degradation efficiency of $CoS_2-G-TiO_2$ nanocomposite was found approximately 89% of Reactive Black B (RBB) degraded after 180 min. Our results will open new way for the development of a new ternary nanocomposite photocatalytic application.

• Journal of Ecology and Environment
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• v.29 no.6
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• pp.559-563
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• 2006

This work was investigated the effects of the elevated $CO_2$ and Pb contamination on the growth of Pinus densiflora. Two-years pine trees were planted in Pb-contaminated soils (500 mg/kg-soil) and uncontaminated soils, and cultivated for 3 months in the growth chamber where $CO_2$ concentration was controlled at 380 or 760 ppmv. The growth of P. densiflora were comparatively analyzed in 4 kinds of soil samples (CA : $CO_2$ 380 ppmv + Pb 0 mg/kg, CB : $CO_2$ 380 ppmv + Pb 500 mg/kg, EA : $CO_2$ 760 PPmv + Pb 0 mg/kg, EB : $CO_2$ 760 ppmv + Pb 500 mg/kg). It was measured the growth changes of the p. densiflora caused by $CO_2$ concentration and Pb contamination. The growth of P. densiflora was remarkably inhibited in the Pb-contaminated soil, although the biomass and the root elongations were not significantly affected by the elevated $CO_2$. These results suggested that the growth of p. densiflora was sensitively influenced by Pb contamination rather than $CO_2$ concentration. Compared to the initial soil, total Pb concentration in the soil samples was decreased at 760 ppmv $CO_2$ as well as at 380 ppmv $CO_2$ after 3 months. The accumulation of Pb in the roots at 760 ppmv $CO_2$ was two-fold of that at 380 ppmv $CO_2$, indicating that Pb bioavailability in the root of p. densiflora might be affected by the elevated $CO_2$.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.11
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• pp.1814-1818
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• 1989

The crystals of ZnGa2S4 and ZnGa2S4:Co(2mole%) were synthesized from high-purity (99.999%) elements of Zinc, Gallium, and sulfur. The crystal structure of these crystals belong to a tetragonal system with layer type and the lattice constants are a =5.35\ulcorner c=10.43\ulcornerfor ZnGa2S4: Co(2 mole%) crystal at 298\ulcorner. The optical absorption spectra of these compounds were obtained through reflectance measurements using a 60 mm diameter intergrating sphere. The optical energy gaps are 3.18eV for ZnGa2S4 and 2.60eVfor ZnGa2S4:L Co(2mole%)at 298\ulcorner, respectively.

• Bulletin of the Korean Chemical Society
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• v.23 no.6
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• pp.851-856
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• 2002

The Reaction of S-methyl-S-cysteine(L-Smc) with racemic $s-cis-[Co(demba)Cl_2]-1$ (Hydmedba = $NN'-dimethylethylenediamine-NN'-di-\alpha-butyric$, acid) yields ${\Delta}$-s-cis-[Co(dmedba)(L-Smc)] 2 with N, O-chelation. Oxidation of sulfur of 2 with $H_2O_2$ in a 1 : 1 mole ratio gives ${\Delta}$-s-cis[Co(dmedba)(L-S(O)mc)] 3 having an uncoordinated sulfenate group. Oxidation of sulfur of L-Sm with $H_2O_2in$ a 1: 1 mole ratio produces S-methyl-L-cysteinesulfenate (L-S(O)me) 5. Direct reaction of 1 with 5 in basic medium gives an N.O-chelated ${\Delta}$s-cis[Co(dmedba)(L-S(O)mc)-N.O], which turmed out be same as obtained by oxidation of 2, while an N, S-chelated ${\Delta}$-s-cis-[Co(dmedba)(S-S(O)mc)-N,O] complex 4 is obtained in acidic medium from the reaction of 1 with 5. This is one of the rare $[$Co^{III}$(N_2O_2-type$ ligand)(amino acid)] type complex preparations, where the reaction conditions determine which mode of N, O and N, S caelation modes is favored.

• Journal of the Korean Ceramic Society
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• v.35 no.12
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• pp.1329-1336
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• 1998

A twt -step carbothermal reduction scheme has been employed for the synthesis of SiC whiskers in an Ar or a H2 atmosphere via vapor-solid two-stage and vapor-liquid-solid growth mechanism respectively. It has been shown that the whisker growth proceed through the following reaction mechanism in an Ar at-mosphere : SiO2(S)+C(s)-SiO(v)+CO(v) SiO(v)3CO(v)=SiC(s)whisker+2CO2(v) 2C(s)+2CO2(v)=4CO(v) the third reaction appears to be the rate-controlling reaction since the overall reaction rates are dominated by the carbon which is participated in this reaction. The whisker growth proceeded through the following reaction mechaism in a H2 atmosphere : SiO2(s)+C(s)=SiO(v)+CO(v) 2C(s)+4H2(v)=2CH4(v) SiO(v)+2CH4(v)=SiC(s)whisker+CO(v)+4H2(v) The first reaction appears to be the rate-controlling reaction since the overall reaction rates are enhanced byincreasing the SiO vapor generation rate.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.7
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• pp.579-583
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• 2003

HgGa$_2$S$_4$: Co$^{2＋}$ single crystal were grown by the chemical transport reaction(CTR) method. In the optical absorption spectrum of the HgGa$_2$S$_4$: Co$^{2＋}$ single crystal measured at 298K, three groups of impurity optical absorption peaks consisting of three peaks, respectively, were observed at 673nm, 734nm, and 760nm, 1621nm, 1654nm, and 1734nm, and 2544nm, 2650nm, and 2678nm. At 10K, the three peaks(673nm, 734nm, and 760nm) of the first group were split to be twelve peaks. These impurity optical absolution peaks are assigned to be due to the electronic transitions between the split energy levels of Co$^{2＋}$ sited in the S$_4$ symmetry point.