• Bulletin of the Korean Chemical Society
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• v.27 no.11
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• pp.1825-1831
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• 2006

The influence of solvent viscosity on conformational dynamics of the heme-pocket, a small vacant site near the binding site of myoglobin (Mb) and hemoglobin (Hb), and playing a functionally important role by serving as a station in ligand binding and escape, was studied by probing time-resolved vibrational spectra of CO photodissociated from MbCO and HbCO in $D_2O$, 75 wt% glycerol/$D_2O$, and trehalose at 283 K. Two absorption bands ($B_1$ and $B_2$) of the sample in viscous solvents, arising from CO in the heme pocket, are very similar to those in $D_2O$. Two bands in Mb and Hb under all three solvents exhibit very similar nonexponential spectral evolution ($B_1$ band; blue shifting and broadening, $B_2$ band; narrowing with a negligible shifting), suggesting that in the present experimental time window of 100 ps, the extents of the spectral shift and narrowing is much influenced neither by the viscosity of solvent nor by the quaternary contact of Hb. Spectral evolution can be described by a biexponential function with a fast universal time constant of 0.52 ps and a slow time constant ranging from 13 to 32 ps. For both proteins in all three solvents majority of spectral evolution occurs with the fast universal time constant. The magnitude of the slow rate in the spectral shift of B1 band decreases with increasing solvent viscosity, indicating that it is influenced by global conformational change which is retarded in viscous solvent, thereby serve as a reporter of global conformational change of heme proteins after deligation.

• Journal of Microbiology and Biotechnology
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• v.14 no.5
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• pp.901-905
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• 2004

The degradation and mineralization of crude oil were investigated over 50-days in three soils, loamy sand, sand, and combusted loamy, which were artificially contaminated with crude oil (50 g $kg^{-1}$) and inoculated with Nocardia sp. H17-1. The degradation efficiency of total petroleum hydrocarbon (TPH) in sand was the highest at 76% among the three soils. The TPH degradation rate constants $(k_{TPH})$ in loamy sand, sand, and combusted loamy sand were 0.027 $d^{-1}$, 0.063 $d^{-1}$, and 0.016 $d^{-1}$, respectively. In contrast, the total amount of $CO_2$ evolved was the highest at 146.1 mmol in loamy sand. The $CO_2$ evolution rate constants (k_{CO2})$ in loamy sand, sand, and combusted loamy sand were 0.057 $d^{-1}$, 0.066 $d^{-1}$, and 0.037 $d^{-1}$, respectively. Therefore, it seems that the degradation of crude oil in soils can be proportional to the soil pore space and that mineralization can be accelerated with the increase of organic substance.

• Journal of Korean Society of Forest Science
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• v.69 no.1
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• pp.13-18
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• 1985

Forest soils mixed with organic matters (green needle, flesh needle litter and needle litter in F layer of Pinus koraiensis, and green leaf of Quercus dentata and Q. variabilis) were incubated under a constant $30^{\circ}C({\pm}1)$ for 53 days to measure the changes of inorganic nitrogen and $CO_2$ evolution rate. The results obtained were summarized as follows; 1) In the early incubation period the amounts of total inorganic nitrogen in soils by mixture of organic matters decreased rapidly because of immobilization by microbial uptake, and thereafter their amounts increased with further incubation. 2) The rate of immobilization of organic nitrogen in mixed organic matters was the highest in green needle among green needle, flesh needle litter and needle litter in F layer of P. koraiensis, but lower than that of green leaf of Q. variabilis and Q. dentata. 3) The rates of $CO_2$ evolution from soils mixed with organic matters increased sharply in the early time, and then decreased slowly with increasing time. The order of the $CO_2$ evolution rate was green leaf of Q. variabilis > green leaf of Q. dentata > green needle of P. koraiensis > flesh needle litter of P. koraiensis > needle litter of P. koraiensis in F layer from the largest to the least. 4) Nitrate nitrogen concentrations showed a tendency to increase throughout incubation time, so that their concentrations after 53 days were higher than that of ammonium nitrogen.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.4
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• pp.308-317
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• 2015

To investigate the effect of microstructure on the formation of the desorption peak, the volumetric thermal analysis technique (VTA) was applied to the Mg-13.5 wt% Ni hydride system. The sample made by the HCS (hydriding combustion synthesis) process had two kinds of Mg microstructures. Linear heating was started with various constant heating rates. Only one peak was appeared in the case of the small initial hydrogen wt% (0.83 wt%). Yet, two peaks were appeared with increasing initial hydrogen wt% (1.85 and 3.73 wt%) when only Mg was hydrogenated. The first peak was formed through the evolution of hydrogen from $MgH_2$, made by eutectic Mg. The second peak was formed through the evolution of hydrogen from $MgH_2$, made by primary Mg. Therefore, this result shows that the microstructure also has a considerable effect on forming the desorption peak. We have also derived the hydrogen desorption equations by VTA to get apparent activation energy when the rate-controlling step for the desorption of the hydrided system is the diffusion of hydrogen through the ${\alpha}$ phase and the chemical reaction ${\beta}{\rightarrow}{\alpha}$.

• Journal of Environmental Health Sciences
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• v.32 no.6
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• pp.578-584
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• 2006

This research was conducted to estimate the effect of C/N ratio control on composting of TNT (2,4,6 trinitrotoluene)-contaminated soil. Glucose or acetone was selected to control C/N ratio of the contaminated soil. The C/N ratios of the controlled experiment and no controlled one were 26.0 and 6.6, respectively. During 45days, the degradation efficiency (96.0 or 91.8%) of acetone or glucose C/N ratio controlled soil was higher than that (78.4%) of no C/N ratio controlled case. The first order degradation rate constant of glucose or acetone C/N ratio control was 0.0641 or 0.0820/day. This constant was over twice 0.0356/day of no C/N ratio control. The C/N ratio control with glucose or acetone also showed a rather high $CO_2$ evolution than that without C/N ratio control. It was proven that C/N ratio control for composting of TNT-contaminated soil improved the treatment efficiency.

• Korean Journal of Environmental Biology
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• v.27 no.4
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• pp.353-362
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• 2009

This study attempted to compare the litter decomposition rate of Arundinella hirta and Miscanthus sinensis var. purpurascens which collected from serpentine soil acting potentially toxic concentration of heavy metals and non-serpentine soil by using the microcosm method for 192 days under constant humidity and $23^{\circ}C$. The contents of Ni, Fe, Mg and Cr in the serpentine and nonserpentine soil originated litter showed high differences between them. The litter samples from serpentine site have lower C/N than non-serpentine litter, but the soluble carbohydrate content was shown almost similar between two plant litter. The mass loss rates of leaf litter from serpentine area were slower than those from non-serpentine site. During the experimental period, the remained dry weight of A. hirta and M. sinensis var. purpurascens litter collected from serpentine site were 64.7%, 65.0% of initial dry weight and litter samples from non-serpentine site showed 54.2%, 50.7%, respectively. K and Na were leached rapidly at the initial decomposition periods, but Ca showed immobilization and other metal elements reserved at the decomposing litter for a long time. The decomposing A. hirta litter from non-serpentine soil showed higher values of $CO_2$ evolution, microbial biomass-C, and microbial biomass-N than those in serpentine soil originated litter acting nutrient stresses and exhibited rapid decay rate. The microbial biomass and microbial respiration of decaying litter were positively correlated with litter decomposition rate, and these relationships showed more rapid slope in non-serpentine soil originated litter than that in serpentine soil.