• Journal of the Korean Chemical Society
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• v.54 no.4
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• pp.479-486
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• 2010

The purposes of this study are to investigate the description of scientifically debatable carbonic acid in the Korean high school textbooks, characterize the physical properties of 'carbonic acid solutions' by using an MBL set-up and compare the properties with textual ones. Four different aqueous solutions of carbon dioxide have been prepared and analyzed: naturally aerated aqueous solution, dry ice-dissolving solution, $CO_2$-bubbling solution and commercial carbonic acid water. Experimental findings showed that pH and conductivity of these 4 solutions ranged from 3.85 to 5.66 and from 0.21 ${\mu}S$/cm to 272.1 ${\mu}S$/cm, respectively. Out of these solutions, the dissociation constant($K_{a1}$) of the bubbling solution at room temperature could be calculated to $5.7{\times}10^{-7}$ which value is comparable to the textual $4.3{\times}10^{-7}$ within experimental errors, which means that textual compound is not pure carbonic acid but the equilibrated mixture of carbonic acid and the aqueous solution of carbon dioxide. On the other hand, textual analysis showed that most of high school textbooks used carbonic acid as an example of weak acid and buffer solution of the blood but none of them distinguished the carbonic acid from the aqueous solution of carbon dioxide. Only one textbook, however, tiered two species in the chemical equation.

• Journal of Energy Engineering
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• v.26 no.2
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• pp.73-79
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• 2017

In nucleation assisted crystallization process formed $CO_2$ leaves as colloid gas and is used as the template by the rapidly growing crystals in the nucleation site. This emulsion of $CaCO_3$ micro-crystals & $CO_2$ micro-bubbles forms hollow particles. Formed hollow particles are double walled, both internal and external faces belonging to the cleavage aragonites which separate the surrounding water from the enclosed gas cavity. Hence, the reverse reaction of $CO_2$ with water forming Carbonic Acid is not possible and the pH stability is maintained. In fact every excess $CaCO_3$ crystals are buffering any carbonic acid left over. This $CO_2$ based nucleation technology prevents scale formation in water channels, but it also helps to reduce the previously formed scales. This process takes out water dissolved $CO_2$ in almost-visible micro-bubbles forms that helps reducing previously formed scale over a period of time (depends on the usage period). The aragonite crystals can't form scale because of its stable molecular structure and neutral surface electro potentiality.

• Journal of Life Science
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• v.23 no.12
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• pp.1557-1561
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• 2013

Carbonic anhydrase isozymes are a widespread, zinc-containing metalloenzyme family. The enzyme catalyzes the reversible inter-conversion of $CO_2$ and $HCO_3$. This reaction is the main role played by CA enzymes in physiological conditions. This enzyme has been found in virtually all organisms, and at least 16 isozymes have been isolated in mammals. Unlike mammals, there is little information available regarding CA isozymes in the tissues of non-mammalian groups, such as fish. Carbonic anhydrase is very important in the osmotic and acid-base regulation in fish. It is well-known that the gills of fish play the most important role in acid-base relevant ion transfer, the transfer of $H^+$ and/or $HCO_3^-$, for the maintenance of systemic pH. Rainbow trout, Oncorhynchus mykiss, is the most important freshwater fish species in the aquaculture industry of Korea, with annual production increasing each year. In addition, environmental toxicology research has shown that rainbow trout is known to be the species that is most susceptible to environmental toxins. Consequently, carbonic anhydrase was detected in rainbow trout, Oncorhynchus mykiss. The isolated protein showed the specific band with a molecular weight of 30 kDa and pI of 7.0, and it was identified as being carbonic anhydrase. The immunohistochemical result demonstrated that the carbonic anhydrase was located in the epithelial cells of the gills.

• Ocean and Polar Research
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• v.44 no.3
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• pp.209-220
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• 2022

Carbonic anhydrase (CA) is a key controller of the carbon concentrating mechanism (CCM), and is known to be affected by ambient pH and CO₂ compositions. Herein, we characterized three novel CAs genes (PmCA1, 2, and 3) from the marine dinoflagellate Prorocentrum minimum, and evaluated the relative expressions of the PmCAs and photosynthetic genes PmatpB and PmrbcL under different pH conditions. Each PmCA was predicted to have amino acid residues constituting the zinc binding site. With signal peptide, PmCA1 and PmCA2 were predicted to be intracellular CAs located in the cytoplasm and chloroplast membrane, respectively. On the other hand, PmCA3 was predicted to be extracellular CA located in the plasma membrane. Also, PmCA1 was classified into the beta family, and PmCA2 and PmCA3 were classified into the alpha family via phylogenic analysis. The photosynthesis efficiency of P. minimum was similar at pH 7 to 9, and decreased significantly at pH 6 and pH 10. Overall, relative gene expression levels of the three PmCAs decreased at low pH, and increased as pH increased. Photosynthesis related genes, PmatpB and PmrbcL, showed similar expression patterns to those of PmCAs. These results suggest that changes in seawater pH may affect photosynthesis and CO₂ metabolism in marine dinoflagellates.

• Journal of the Society of Naval Architects of Korea
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• v.61 no.1
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• pp.51-60
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• 2024

Hi Air Korea and Hanwha ocean are currently developing an Onboard Carbon dioxide Capture System (OCCS) to absorb CO₂ emitted from ship's engine using a sodium hydroxide(NaOH) solution, and converting the resulting salt into a solid form through a chemical reaction with calcium oxide (CaO). The system process involves the following steps; 1)The reaction of CO₂ gas absorption in water, 2)The reaction between carbonic acid (H₂CO₃) and NaOH solution to produce carbonate or bicarbonate, and 3)The reaction between carbonate or bicarbonate and CaO to form calcium carbonate (CaCO₃). And ultimately, the solid material, CaCO₃, is separated and discharged using a separator. The OCCS has been installed on an ship and the test results have confirmed significant reduction effects of CO₂ in the ship's exhaust gas. A portion of the exhaust gas emitted from the engine was transferred to the OCCS using a blower. The flow rate of the transferred gas ranged from 800 to 1384 m³/hr, and the CO₂ concentration in the exhaust gas was 5.1 vol% for VLSFO, 3.7 vol% for LNG and a 12 wt% NaOH solution was used. The results showed a CO₂ capture efficiency of approximately 42.5 to 64.1 vol% and the CO₂ capture rate approximately 48.4 to 52.2kg/hr. Additionally, to assess the impact of the discharged CaCO₃on the marine ecosystem, we conducted "marine ecotoxicity test" and performed Computational Fluid Dynamics (CFD) analysis to evaluate the dispersion and dilution of the discharged effluent.

• Journal of Life Science
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• v.24 no.2
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• pp.186-190
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• 2014

Carbonic anhydrase isozymes (CAs) are widespread zinc-containing metalloenzyme family. The enzyme catalyzes the reversible interconversion of $CO_2$ and $HCO_3$. This reaction is the main role of CA enzymes in physiological conditions. CA III, one of the CA isozymes, has been identified in many tissues. It is distinguished from the other isozymes by several characteristics, particularly by a lower specific activity and by its resistance to acetazolamide. However, the physiological function of CA III in fish is unknown. In this study, we examined the detection of CAs in the Shaggy sea raven Hemitripterus villosus, using SDS-PAGE, isoelectric focusing (IEF), and western blot analysis. We detected a significant protein band with molecular weight about 30 kDa from the tissues of H. villosus by SDS-PAGE and western blotting. A specific band of CA III with pI 7.0 was detected by IEF and western blotting in gill and muscle. The immunoreaction of anti-CA III expressed in the gill of H. villosus was much stronger than other tissues. One explanation for this result is that the fish gill is the only organ that is exposed to the external environment and that plays an important role in acid-base relevant ion transfer, the transfer of $H^+$ and/or $HCO{_3}^-$, for the maintenance of systemic pH. This is the first report on the identification of a carbonic anhydrase III-like protein from H. villosus.

• Journal of Sericultural and Entomological Science
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• v.29 no.2
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• pp.73-81
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• 1987

This investigation was carried cut to obtain the reeling water conditions in Korea. The analyzed items of water were pH, colority, turbidity, acidity, alkalinity, solids electric conductibity hardness and heavy metal ions. About 40% of the reeling water were found to be agreeable, 30% were acceptable provided with some quality control and the others were out of acceptable range mainly based on the M-alkalinity, acidity, pH and total hardness. It was found that there was a following relationship between total hardness and electric conductibity with the relative correlation coefficient r=0.9145. y=15.967+0.22774x Where x, y are electric conductivity and total hardness respectively.

• Korean Journal of Ecology and Environment
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• v.35 no.3 s.99
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• pp.145-151
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• 2002

The effect of low pH on physiological changes was studied with the acidophilic green alga, Clamydomonas acidophila, UTCC 122. The growthrates (${\mu}$) were identical, $0.5{\sim}0.7\;day^{-1}$, at pH 3.7${\sim}$6.7 and no significantly different (ANOVA, p =0.134), showing cell volume reduced gradually as they were growing, whereas that at pH 2.7 was falling to zero and cell volume increased dramatically. Chlorophyll a concentration of the cultures incubated for one day was $191{\sim}255\;pg\;cell^{-1}$, after then it declined from $60{\sim}103\;pg\;cell^{-1}$ at pH 3.7${\sim}$6.7 except $210\;pg\;cell^{-1}$ at pH 2.7, which was directly related with cell volume. External carbonic anhydrase (CA) activity was varied from1.1 to$3.7{\times}10^{-4}\;E.U.\;mm^{-2}$, showing the gradualincrease during culture, except at 2.7 and pH 5.7. However there was not found any relationship among the pH gradient cultures. CA molecular mass of C. acidophila was 29 kBa, and concentration of that was identical in all cultures. The proteins of 41 kDa and 63 were not or very　faintly expressed in low pH cultures, in contrast that of 17 kDa more expressed. In this work, we found that C. acidophila could live optimally within a wide range of acidic pH, and 17 kDa of unidentified protein might be concerned with tolerating in low acid environment.

• 보존과학연구
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• s.24
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• pp.169-184
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• 2003

Yearly mean temperature and relative-humidity of the Seokguram Grotto was measured $19~23^{\circ}C$, 40~44% from May, 1998 to December,2002. The measurement has little differences comparing to the optimum guideline (temperature : $20^{\circ}\pm2^{\circ}C$, relative-humidity : $50^{\circ}\pm5%$). It is necessary to increase humidity in the Seokguram Grotto during winter because of heating and decrease the temperature during summer because of a higher temperature of outside. In addition, the diurnal range keep in $4^{\circ}C$ of temperature and in 10% of relative-humidity. Yearly mean concentration of $CO_2$(carbon dioxide) was measured538~658ppm that is higher than concentration of normal atmosphere(360 ppm). The $CO_2$ has an cumulative effect on the surface of stone cultural properties as a form of carbonic acid($H_2CO_3$) after reaction with water. HVAC (Heating, Ventilation and Air Conditioning) system should be operated to maintain ideal state for the preservation according to the optimum guideline. Also, the entrance into the Seokguram Grotto should be controlled to prevent a sudden fluctuation of humidity and temperature. Human could carry small particles like a microdust, microbe, etc., into the Seokguram Grotto and also could damage the surface by a direct touch.