• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.28 no.3
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• pp.217-221
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• 2022

Container system automatically controlled in its atmosphere of high CO₂/low O₂ was devised to contain and store pork belly meat at chilled temperature. The meat in the container system was compared in the quality preservation at 0℃ for 21 days to that in air-filled container and vacuum package. The container atmosphere could be controlled to be of 47~60% CO₂ and 7~10% O₂ through time-controlled intermittent CO₂ injection. The controlled atmosphere in the developed system was effective in suppressing pH change and aerobic bacterial growth contributing to sensory quality preservation. Compared to control of air-filled container, vacuum packaging showed lower microbial growth and slower pH change on the meat but with high drip loss. The devised container system to keep high CO₂ and mildly low O₂ concentrations is effective in the meat quality preservation on overall, and may be extended to a variety of meat products with possible modification tuned for product requirements.

• Journal of the Korean Magnetics Society
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• v.14 no.3
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• pp.89-94
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• 2004

We have investigated magnetic properties of monolayer (ML)-thickness Co film deposited on InP(2${\times}$4) reconstruction surface using in situ Surface Magneto-Optical Kerr Effects (SMOKE) measurement system. InP(2${\times}$4) reconstruction surface, obtained by repeated sputtering and annealing, was confirmed by reflection hish energy electron diffraction (RHEED) and scanning tunneling microscope (STM) measurements. From both longitudinal and polar SMOKE measurements, we have observed three distinguishable regions showing different magnetic properties depending on the Co thickness. In the Co film thickness smaller than 7 $m\ell$, no SMOKE signal was detected. In the following thickness between 8 $m\ell$ and 15 $m\ell$, both longitudinal and polar Kerr hysteresis loops were observed, which implies a metastable phase coexisted of in-plane and perpendicular anisotropies. In the film thickness larger than 16 $m\ell$, only longitudinal MOKE signal without polar signal was detected, which implies existence of in-plane anisotropy in this thickness region.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
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• v.1 no.1
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• pp.51-59
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• 1997

Two comparative poplar clones (I-214: Populus euramericana, Peace: P koreana x P. trichocarpa) were exposed to two $CO_2$ concentrations (350 or 2,000 ${\mu}L\;L^{-1}\;CO_2)$ for 21 days. When both poplar clones were compared at growth conditions, the net photosynthetic rate $(P_N)$ in $CO_2-enriched$ (2,000 ${\mu}L\;L^{-1}\;CO_2=C_{2,000})$ plants become about $50-60\%$ higher than that of 350 ${\mu}L\;L^{-1}\;CO_2(=C_{350})$ plants on 7 days treatment. But the enhancement of $P_N$ by high $CO_2$ was not maintained throughout all the experimental period. At 21 days, there was no difference of photosynthetic rates between $C_{350}\;and\;C_{2,000}$ plants. In contrast with photosynthesis, the response of leaf conductance to the elevated $CO_2$ concentration was very different between I-214 and Peace. During all experimental period, leaf conductance $(g_s)$ of $C_{2,000}$ plants is $50\%$ lower than that of the $C_{350}$ plants for I-214, while there is no difference of $g_s$ between the plants of $C_{350}\;and\;C_{2,000}$ on for Peace. The results of gs in Peace indicate that decreased photosynthetic rate after 21 days in $C_{2,000}$ on plants for two poplar clones is possibly due to non-stomatal factors. To investigate the non-stomatal factors, starch accumulation and ribulose-1,6-bisphosphate carboxylase (RuBPCase) were measured. We found significant accumulation of starch in two poplar clones exposed to high $CO_2,$ especially starch of I-214 in $C_{2,000}$ become 3.5 times higher than in $C_{350}$ plants at 21 days. This suggests that high proportion of photosynthates was directed into starch. After 21 days, the activity of ribulose-1, 6-bisphosphate carboxylase of $C_{2,000}$ plants become decreased in $40-50\%$ compared with that of the $C_{350}$ plants. Two poplar clones show the same trend to RuBPCase declines under high $CO_2$ concentration, although the decline is more significant for I-214. The results reported here suggest that starch accumulation and decreased RuBPCase activity in $C_{2,000}$ plants can be partly ascribed to the loss of photosynthetic efficiency of high $CO_2-grown$ poplar plants.

• Journal of Environmental Science International
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• v.12 no.8
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• pp.853-860
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• 2003

Plants sequester atmospheric CO$_2$, a major agent of climate change, during the growing periods and mitigate its rising accumulation in the atmosphere. Pinus densiflora and Quercus mongolica are the native tree species dominant in the temperate forests of Korea. This study quantified the annual CO$_2$ uptake by the two species at forest sites in Chuncheon in the middle of the country. The quantification was based on seasonal measurements of CO$_2$ exchange rates under natural conditions by an infrared gas analyzer over the growing season (1999). The monthly CO$_2$ uptake per unit leaf area ranged from 1.6-6.7 mg/d㎡/h for P. densiflora and from 3.7-8.9 mg/d㎡/h for Q. mongolica, with a maximum in mid-summer. An equation for each species was generated to estimate easily the annual CO$_2$ uptake by total leaf area per tree, which subtracted the CO$_2$ release (i.e. respiration) by leaves and woody organs from the gross CO$_2$ uptake (diurnal uptake and release by leaves). Annual CO$_2$ release by leaves and woody organs accounted for 58-73％ of the gross CO$_2$ uptake across tree specimens. Annual CO$_2$ uptake per tree increased with increasing dbh (stem diameter at breast height) for the study diameter range, and was greater for Q. mongolica than for P. densiflora in the same dbh sizes. This was mainly associated with a greater total leaf area in the former. For example, the annual CO$_2$ uptake by one tree with dbh of 25 cm was 35.6 kg/yr for P. densiflora and 47.9 kg/yr for Q. mongolica. The results from this study can be applied to evaluate an atmospheric CO$_2$ reduction of woody plants by forest type and age class.

• Economic and Environmental Geology
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• v.51 no.4
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• pp.359-370
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• 2018

The batch and column experiments were performed to overcome the limitation of the neutralization process using the $scCO_2$-water-recycled aggregate, reducing its treatment time to 3 hour. The waste cement mortar and two kinds of recycled aggregate were used for the experiment. In the extraction batch experiment, three different types of waste mortar were reacted with water and $scCO_2$ for 1 ~ 24 hour and the pH of extracted solution from the treated waste mortar was measured to determine the minimum reaction time maintaining below 9.8 of pH. The continuous column experiment was also performed to identify the pH reduction effect of the neutralization process for the massive recycled aggregate, considering the non-equilibrium reaction in the field. Thirty five gram of waste mortar was mixed with 70 mL of distilled water in a high pressurized stainless steel cell at 100 bar and $50^{\circ}C$ for 1 ~ 24 hour as the neutralization process. The dried waste mortar was mixed with water at 150 rpm for 10 min. and the pH of water was measured for 15 days. The XRD and TG/DTA analyses for the waste mortar before and after the reaction were performed to identify the mineralogical change during the neutralization process. The acryl column (16 cm in diameter, 1 m in length) was packed with 3 hour treated (or untreated) recycled aggregate and 220 liter of distilled water was flushed down into the column. The pH and $Ca^{2+}$ concentration of the effluent from the column were measured at the certain time interval. The pH of extracted water from 3 hour treated waste mortar (10 ~ 13 mm in diameter) maintained below 9.8 (the legal limit). From XRD and TG/DTA analyses, the amount of portlandite in the waste mortar decreased after the neutralization process but the calcite was created as the secondary mineral. From the column experiment, the pH of the effluent from the column packed with 3 hour treated recycled aggregate kept below 9.8 regardless of their sizes, identifying that the recycled aggregate with 3 hour $scCO_2$ treatment can be reused in real construction sites.

• Journal of Soil and Groundwater Environment
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• v.6 no.1
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• pp.13-21
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• 2001

The characteristics of $Co^{2+}$ removal in the kaolinite column were analyzed by electrokinetic remediation. Ethanoic buffer was injected in the kaolinite column and $CH_3$COOH was continuously added to the cathode reservoir to restrain the pH increase. The pH of the cathode of the kaolinite column was 4.0 at first. Since it was controlled to be under 6.5 after 43.6 hours due to ethanoic buffer, precipitation of ${Co(OH)}_2$ was not formed in the column. Effluent rate increased with time and $Co^{2+}$ removal in the column at initial time was mainly controlled by ion migration. 13.1% of total $Co^{2+}$ in the column was removed after 10 hours, the 46.8% of total $Co^{2+}$ after 20.8 hours, and the 71.7% of total $Co^{2+}$ after 30.1 hours, the 94.6% of total $Co^{2+}$ after 43.6 hours, Meanwhile, the residual concentrations in the column calculated by the developed model were similar to experiment results.

• Journal of Microbiology and Biotechnology
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• v.32 no.10
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• pp.1335-1343
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• 2022

COVID-19 is an emerging disease that poses a severe threat to global public health. As such, there is an urgent demand for vaccines against SARS-CoV-2, the virus that causes COVID-19. Here, we describe a virus-like nanoparticle candidate vaccine against SARS-CoV-2 produced by an E. coli expression system. The fusion protein of a truncated ORF2-encoded protein of aa 439~608 (p170) from hepatitis E virus CCJD-517 and the receptor-binding domain of the spike protein from SARS-CoV-2 were expressed, purified and characterized. The antigenicity and immunogenicity of p170-RBD were evaluated in vitro and in Kunming mice. Our investigation revealed that p170-RBD self-assembled into approximately 24 nm virus-like particles, which could bind to serum from vaccinated people (p < 0.001) and receptors on cells. Immunization with p170-RBD induced the titer of IgG antibody vaccine increased from 14 days post-immunization and was significantly enhanced after a booster immunization at 28 dpi, ultimately reaching a peak level on 42 dpi with a titer of 4.97 log₁₀. Pseudovirus neutralization tests showed that the candidate vaccine induced a strong neutralizing antibody response in mice. In this research, we demonstrated that p170-RBD possesses strong antigenicity and immunogenicity and could be a potential candidate for use in future SARS-CoV-2 vaccine development.

• Journal of Korean Society of Forest Science
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• v.105 no.1
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• pp.12-18
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• 2016

This study was carried out to investigate the change on soil $CO_2$ efflux rates, soil temperature, soil water content and soil pH by thinning intensity treatments (heavy thinning, light thinning, control) of a black pine (Pinus thunbergii Parl.) stand disturbed by pine wilt disease in Wola National Experimental Forests in Jinju, Gyeongnam province. Monthly variations of soil $CO_2$ efflux rates were not significantly different between the thinning and the control treatments (P>0.05). The annual mean soil $CO_2$ efflux rates were $0.58g\;CO_2m^{-2}h^{-1}$ for the light thinning, $0.49g\;CO_2m^{-2}h^{-1}$ for the heavy thinning and $0.45g\;CO_2m^{-2}h^{-1}$ for the control treatments, respectively. There was a significant exponential relation between soil $CO_2$ efflux rates and soil temperature, but no correlation between soil water content or soil pH and soil $CO_2$ efflux rates. The values of $Q_{10}$ were 3.40 for the light thinning, 3.20 for the heavy thinning and 3.06 for the control treatments, respectively. The results indicate that soil $CO_2$ efflux rates in a black pine stand disturbed by pine wilt disease could be affected by thinning treatments.

• Journal of Korea Foundry Society
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• v.6 no.4
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• pp.284-289
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• 1986

Decarburization phenomena have been studied by plasma in stainless steel, plain carbon steel and cast iron. It was also investigated the movement of impurity element P,S in the plasma jet metal pool. The plasma jet was obtained by $Ar\;-\;CO_2$ gas mixture with 5 kVA DC power source. It produced enough temperature to dissociate into activated oxygen atom by reaction of $CO_2{\leftrightarrows}CO+O^+$ and it reacted with ${\underline{C}}$ in metal pool. Decarburization rate was increased about 5 times in comparing with the conventional induction melted metal pool by $CO_2$ gas decarburization. Even under the Ar plasma jet, decarburization was obtained by agitation of metal bath by $Ar^+$ bombardment and dilution phenomena of carbon atom under the very high plasma temperature. But heavy element P and S are not much removed because they are too heavy in mass to be activated by $Ar^+$ion bombardment. Desulphurization was achieved by $Ar\;-\;CO_2$ plasma in plain carbon steel and cast iron by the reaction of $SO_2({\underline{S}}+O^+)$. But dephosphorization could not be obtained by $Ar\;-\;CO_2$ plasma, because gaseous reaction of phosphorous oxide (${\underline{P}}+O^+$) was not existed.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.47 no.6
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• pp.869-873
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• 2014

Cardiorespiratory variables were measured in flounder Paralicthys olivaceus exposed to acidified seawater equilibrated with a gas mixture containing 5% $CO_2$ gas for 72 h at $20^{\circ}C$. It was found that $CO_2$ produced a significant increase in arterial $PCO_2$ ($PaCO_2$) and significant decreases in arterial pH (pHa). $CO_2$ transiently increased heart rate within 30 min of exposure. After cardiac output was elevated by the increase in heart rate within 30 min, was then reduced by the decrease in both stroke volume and heart rate. The heart responses of flounder differ from those of yellowtail to high $CO_2$ environment.