• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.7
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• pp.528-534
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• 2019

This study analyzes the factors affecting China's carbon emissions from 1985 to 2016. In recent years, the whole industries of China are in the midst of industrialization and have several problems. Now, the low-carbon economy has become the main task of China's economic development. This study analyzes the factors affecting China 's carbon emissions by selecting relevant data onto the Chinese yearbook and using a time series model. The analysis shows that related industries continue to innovate and increase the use of green energy such as electricity, but coal is still the largest share of the energy consumed. As energy use efficiency increases and industrial R&D investment increases year by year, carbon emissions are increasing every year. In addition, there is a stereotype that industry is the biggest factor affecting carbon emissions. The research found that the impact of the industry on China's carbon emissions is declining gradually. While controlling industrial carbon emissions, keeping continue to improve technology development and focusing on carbon emissions from other industries are critical to reduce overall carbon emissions. Based on the empirical results, if we can change stereotypes starting from the nature of the data, we will quickly reach a low carbon sustainable development economy.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.12
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• pp.1263-1269
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• 2005

Horseradish peroxidase, had the phenol degradation rate of 95% in aqueous phase, was covalently immobilized on the surface of reticulated vitreous carbon(RVC) and the degradation of phenol was performed with in situ generated $H_2O_2$-immobilized HRP complex in an electrochemical reactor. The incorporation of carboxylic group on the RVC surface was confirmed by FT/IR spectrometry and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide hydrochloride(EDC) was used for peptide bonds between the carboxylic groups on the RVC surface and amine groups from HRP. The optimal conditions of in situ $H_2O_2$ generation such as concentration($10{\sim}200$ mM) and pH($5.0{\sim}8.0$) of electrolyte, supply of $O_2(10{\sim}50$ mL/min) and applied voltage($-0.2{\sim}-0.8$ volt, vs. Ag/AgCl) from potentiostat/galvanostat were determined by concentration of hydrogen peroxide and current efficiency. It was observed that the RVC immobilized HRP was stable maintaining 89% of the initial activity during 4 weeks. The phenol degradation rate of 86% was attained under the optimal condition of in situ $H_2O_2$ generation.

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.2
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• pp.156-163
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• 2005

This study was conducted to compare the physiological and biochemical responses of P. orientalis and L. tulipifera in response to ozone. One-year-old seedlings of P. orientalis and L. tulipifera were exposed to 100 ppb ozone concentration for 2, 4, or 8 hr/day for 1 week. Photosynthesis, stomatal conductance and ozone uptake rate were measured daily, and chlorophyll fluorescence, carboxylation efficiency, chlorophyll content, and SOD activity were measured after 1 week. In P. orientalis, photosynthesis and stomatal conductance were not decreased in the 2h/day ozone treatment, but the L. tulipifera response was more sensitive even in the 2h/day ozone treatment. Increased treatment time decreased photosynthesis and stomatal conductance. Chlorophyll fluorescence was not significantly different among treatment times. However, carboxylation efficiency decreased with increased treatment time, and L. tulipifera was more sensitive than P. orientalis. Chlorophyll content did not differ with species or treatment time. SOD activity response was greater in L. tulipifera than in P. orientalis, increasing to $131\%$ of pretreatment observations. Therefore it was concluded that L. tulipifera was more responsive and had lower ozone tolerance than P. orientalis.

• KSBB Journal
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• v.11 no.5
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• pp.613-621
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• 1996

The effects of important medium components such as carbon, nitrogen sources and amino acids on the production of cyclosporin A(CyA) were investigated in an immobilized fungal cell fermentation using Tolypocladium inflatum. As carbon sources in the synthetic medium, fructose and maltose stimulated CyA production remarkably compared to glucose when ammonium sulfate was supplemented as a nitrogen source. In the absence of ammonium sulfate in the medium, however, CyA biosynthesis was reduced considerably without regard to C-sources tested. Ammonium sulfate was found to be the best N-source, and also ammonium phosphate and ammonium citrate showed some positive effects on CyA production. Optimum concentration of ammonium sulfate was 10g/L, and supplementation of ammonium sulfate at the start of fermentation was found to be the most efficacious for maximal production of CyA. Among the constituent amino acids of cyclic peptide, CyA, L-valine had the most significant effect on the biosynthesis of CyA, and maximum CyA production was observed when 10 g/L of L-valine was initially added.

• Analytical Science and Technology
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• v.23 no.2
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• pp.165-171
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• 2010

Glucose oxidase ($GOD_{ox}$) immobilized biosensor was fabricated by two methods. In one of the methods, gold nanoparticles (Au-NPs) prepared by ${\gamma}$-irradiation were loaded into the poly(maleic anhydride)-grafted multi-walled carbon nanotube, PMAn-g-MWCNT electrode via physical entrapment. In the other method, the Au-NPs were prepared by electrochemical reduction of Au ions on the surface of PMAn-g-MWCNT electrode and then GODox was immobilized into the Au-NPs. The $GOD_{ox}$ immobilized biosensors were tested for electrocatalytic activities to sense glucose. The sensing range of the biosensor based on the Au-NPs physically modified PMAn-g-MWCNT electrode was from $30\;{\mu}M$ to $100\;{\mu}M$ for the glucose concentration, and the detection limit was $15\;{\mu}M$. Interferences of ascorbic acid and uric acid were below 7.6%. The physically Au deposited PMAn-g-MWCNT paste electrodes appear to be good sensor in detecting glucose.

• Applied Chemistry for Engineering
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• v.19 no.5
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• pp.526-532
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• 2008

The proposed $CO_2$ storage technology in the present study is a one-step sequestration process that stabilizes $CO_2$ in a reactor with Serpentine. The advantage of this technology is associated with its high stability of final product so that the entire system is recognized as permanent environment-friendly $CO_2$ removal method. Since the sequestration reaction mechanisms are generally understood that carbonation reaction proceeds with very slow rate, so that pretreatment method to increases reaction rate of $CO_2$ carbonation reaction should be developed. To increase the reactivity of Serpentine with $CO_2$, two different methods of pretreatment are carried out in the present investigation. One is heat-treatment, the other is chemical pretreatment. In this study, only chemical pretreatment is considered leaching method of magnesium from Serpentine using sulfuric acid at the various reaction temperatures, times, and acid concentrations. Experimental results illustrated that pretreatment by sulfuric acid increases surface area of serpentine from $11.1209m^2/g$ to $98.7903m^2/g$ and extracts magnesium compounds. Single variable experiment demonstrated the enhancements of magnesium extraction with increased reaction temperature and time. Amount of magnesium extraction is obtained by using the data of ICP-AES as maximum extraction condition of magnesium is 2 M acid solution, $75^{\circ}C$ and 1hr. After performing chemical pretreatment, carbonation yield increased from 23.24% to 46.30% of weight.

• Journal of Aquaculture
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• v.12 no.1
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• pp.47-56
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• 1999

Denitrification by anaerobic bacteria is one of the most common processes of removing nitrate from recirculating aquaculture systems. This process is affected by many factors such as external carbon sources, hydraulic retention time (HRT), and $COD/NO_3-N$ ratio. Although external organic carbon sources are essential for the denitrification process, these also contribute to increase dissolved organic carbon concentration in recirculating aquaculture systems. So these external organic carbons must be removed from the systems. This study was conducted to find out the optimum operating conditions for the removal of external organic carbons in a submerged denitrification biofilter. Combinations of two external carbon sources (glucose and methanol), two HRT (4- and 8-hour), and four different C:N ratios (3, 4, 5, and 6) were used in this experiment. The removal efficiencies of organic carbon sources at 8-hour HRT were always better than those at 4-hour's (P<0.05). Maximum removal efficiencies were achieved when C:N ratio was 5 in both glucose and methanol. The removal efficiencies of methanol were always better than those of glucose. The maximum removal efficiencies of glucose and methanol were 76.5% and 84.0%, respectively and the removal rates were 223.5 $g/m^2/day$ and 247.1$g/m^2/day$. The maximum removal rates of glucose (290.9 $g/m^2/day$) and methanol (355.6 $g/m^2/day$) were achieved at 4-hour HRT and 5 C:N ratio. But the concentrations of SCOD in the effluent of both glucose ($52.5 mg/\ell$) and methanol ($40.9 mg/\ell$) were too high for rearing fish. Therefore, the optimum operating conditions for the removal of external carbon in a submerged denitrification biofilter were 8-hour HRT and 5 C:N ratio. And methanol showed better efficiency as an external carbon sources.

• Korean Journal of Agricultural and Forest Meteorology
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• v.10 no.2
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• pp.47-57
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• 2008

Physiological and biochemical changes of five species of genus Quercus exposed to ozone fumigation were investigated to assess their tolerance against ozone toxicity. At the end of 150 ppb ozone fumigation, chlorophyll contents, photosynthetic characteristics, malondialdehyde(MDA) and antioxidative enzyme activities were measured in the leaves of five Quercus species(Quercus acutissima, Q. aliena, Q. palustris, Q. serrata, and Q. variabilis). Chlorophyll and carotenoid contents, net photosynthesis and carboxylation efficiency decreased after ozone treatment, indicating that $O_3$-exposed plants underwent physiological inhibition. The reduction rate of total chlorophyll contents and carboxylation efficiency were respectively 15% and 34% for Q. aliena and 38% and 62% for Q. variabilis. The amount of MDA increased with the highest increase rate of 140% in Q. acutissima which also showed the highest increase rate(60%) of superoxide dismutase(SOD). Ascorbate peroxidase(APX) activity increased in Q. variabilis, Q. serrata and Q. acutissima by ozone treatment. Based on our results, ozone tolerance of the five Quercus species was ranked as Q. aliena>Q. palustris>Q. serrata>Q. variabilis>Q. acutissima. We concluded that chlorophyll contents, photosynthesis, MDA content and antioxidative enzymes were the important physiological markers for tolerance against ozone stress, which were closely related with one another.

• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.1059-1066
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• 2009

Recently, the amount of thermosetting plastic wastes has increased with the production of reinforced plastic composites and causes serious environmental problems. The epoxy resins, one of the versatile thermosetting plastics with excellent properties, cannot be melted down and remolded as what is done in the thermoplastic industry. In this research, a series of experiments that decompose epoxy resin and recover carbon fibers from carbon fiber reinforced epoxy composites applied to railway vehicles was performed. We experimentally examined various decomposition processes and compared their decomposition efficiencies and mechanical property of recovered carbon fibers. For the prevention of tangle of recovered carbon fibers, each composites specimen was fixed with a Teflon supporter and no mechanical mixing was applied. Decomposition products were analyzed by scanning electron microscope (SEM), gas chromatography mass spectrometer (GC-MS), and universal testing machine (UTM). Carbon fibers could be completely recovered from decomposition process using nitric acid aqueous solution, liquid-phase thermal cracking and pyrolysis. The tensile strength losses of the recovered carbon fibers were less than 4%.

• Membrane Journal
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• v.22 no.4
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• pp.243-250
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• 2012

The effect of water back-flushing period (filtration time, FT) was investigated in hybrid process of alumina microfiltration and photocatalyst for advanced drinking water treatment in this study, and compared with the previous studies with carbon microfiltration or alumina ultrafiltration membranes. The FT was changed in the range of 2~10 min with fixed 10 sec of BT. Then, the FT effects on resistance of membrane fouling ($R_f$), permeate flux (J) and total permeate volume ($V_T$) were observed during total filtration time of 180 min. As decreasing FT, $R_f$ decreased and J increased as decreasing FT, which was same with the previous results with carbon microfiltration or alumina ultrafiltration membranes. The treatment efficiency of turbidity was high beyond 98.1%, and the effect of FT was not shown on treatment efficiency of turbidity, which was same with the previous result of carbon microfiltration. The treatment efficiency of organic matters was the highest value of 89.6 % at FT 8 min, which was a little higher than those of the previous results, and the effect of FT was not shown on treatment efficiency of organic matters.