• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.61.2-61.2
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• 2007

• Journal of Applied Biological Chemistry
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• v.64 no.4
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• pp.351-356
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• 2021

Changing environmental conditions can affect plant growth by influencing water and nutrient transport and photosynthesis. Plant physiological responses under changing environmental conditions can be non-destructively monitored using electrodes as plant induced electrical signal (PIES). Objective of the study was to monitor PIES in response to increased CO₂ and decreased photosynthetic photon flux density (PPFD). The PIES increased during day time when transpiration and photosynthesis occurs and monitored CO₂ concentration was negatively correlated to the PIES. Enhanced CO₂ concentration slightly reduced PIES, but the effect of increased CO₂ was limited by light intensity. The effect of reduced PPFD was not appeared immediately because water and nutrient transport was not promptly affected by the light. The study was conducted to evaluate short-term effect of increasing CO₂ and decreasing PPFD, hence proline content and chlorophyll fluorescence was not significantly affected by the conditions.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.12
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• pp.1415-1420
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• 2014

Super-critical $CO_2$ ($S-CO_2$) Brayton cycle has been considered to replace the current steam Rankine cycle in Sodium-cooled Fast Reactor (SFR) in order to improve the inherent safety and thermal efficiency. Several austenitic alloys are considered as the structural materials for high temperature $S-CO_2$ environment.. Microstructural change after long-term exposure to high temperature $S-CO_2$ environment could affect to the mechanical properties. In this study, candidate materials (austenitic stainless steels and Alloy 800HT) were exposed to $S-CO_2$ to assess oxidation resistance and the change in tensile properties. Loss of ductility was observed for some austenitic stainless steels even after 250 h exposure. The contribution of $S-CO_2$ environment on such changes was analyzed based on the characterization of the surface oxide and carburization of the materials in which 316H and 800H showed different oxidation behaviors.

• Analytical Science and Technology
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• v.11 no.6
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• pp.448-451
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• 1998

The feasibility of using FT-NIR (Fourier Transform Near Infrared) spectrometer to measure NaOH, $Na_2CO_3$ and $Na_2S$ concentration in a naphtha cracking process, and an outline of the method development to identify spectral feature of the hydroxide whose band is overlapped by a strong water absorption were demonstrated. For measuring NaOH, $Na_2CO_3$ and $Na_2S$, FT-NIR spectrometer is a rapid and possible alternative to the current titration method with a standard deviation of 0.1.

• The Plant Pathology Journal
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• v.17 no.6
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• pp.370.2-370
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• 2001

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.5
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• pp.296-302
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• 1999

$CdIn_2S_4 and CdIn_2S_4 : Co^{2+}$ singlecrystals of thenormal spinel structure were grown by the C.T.R. method. The optical energy band structure of these compounds had a indirect band gap at the fundamental optical absorption band edge. The direct and the indirect energy gaps are found to be 2.325 and2.179eV for $Cdln_2S_4$ , and 2.303 and 2.169eV for $CdIn_2S_4 and CdIn_2S_4 : Co^{2+}$ at 5K, respectivly. The fundamental absorption band edge of these single crystals shift to a shorter wavelength region with decreasing temperature, and the temperature dependence of the optical energy gaps in these compounds satisfy Varshni equation. The Varshni constants$\alpha and \beta$ of the direct energy gap are given by $13.39{\times}10_{-4}eV/K$ and 509 K for $Cdln_2S_4$ and $29.73{\times}10_{-4} eV/K$ and 1398K for $CdIn_2S_4 and CdIn_2S_4 : Co^{2+}$. The Varshni constants ${\alpha}and {\beta}$ of the indirect energy gap are given by 9.68${\times}10^{-4}$ eV/K 308K for $Cdln_2S_4$ and $13.33{\times}10_{-4}eV/K$ and 440K for $CdIn_2S_4 : Co^{2+}$ respectivly. The impurity optical absorption peaks due to cobalt dopant are observed in $CdIn_2S_4 : Co^{2+}$ single crystal. These impurity optical absorption peaks can be attributed to the electronic transitions between the split energy levels of $Co_{2+}$ ions located at $T_d$ symmetry site of $Cdln_2S_4$ host lattece.

• Microbiology and Biotechnology Letters
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• v.48 no.4
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• pp.547-555
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• 2020

Microalgae are a promising resource in energy and food production as they are cost-effective for biomass production and accumulate valuable biological resources. In this study, CO2 assimilation, biomass, and lipid production of 4 microalgal species (Chlorella vulgaris, Mychonastes homosphaera, Coelastrella sp., and Coelastrella vacuolata) were characterized at different CO2 concentrations ranging from 1% to 9%. Microscopic observation indicated that C. vulgaris was the smallest, followed by M. homosphaera, C. vacuolata, and Coelastrella sp. in order of size. C. vulgaris grew and consumed CO2 more rapidly than any other species. C. vulgaris exhibited a linear increase in CO2 assimilation (up to 9.62 mmol·day-1·l-1) as initial biomass increased, while the others did not (up to about 3 mmol·day-1·l-1). C. vulgaris, Coelastrella sp., and C. vacuolata showed a linear increase in the specific CO2 assimilation rate with CO2 concentration, whereas M. homosphaera did not. Moreover, C. vulgaris had a greater CO2 assimilation rate compared to those of the other species (14.6 vs. ≤ 11.9 mmol·day-1·l-1). Nile-red lipid analysis showed that lipid production per volume increased linearly with CO2 concentration in all species. However, C. vulgaris increased lipid production to 18 mg·l-1, compared to the 12 mg·l-1 produced by the other species. Thus, C. vulgaris exhibited higher biomass and lipid production rates with greater CO2 assimilation capacity than any other species.

• Journal of Bio-Environment Control
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• v.32 no.1
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• pp.64-71
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• 2023

Crassulacean acid metabolism (CAM) plants use surplus CO₂ generated by cooling and heating at night when ventilation is not needed in a greenhouse. Schlumbergera truncata 'Pink Dew' is a multi-flowering cactus that needs more phylloclades for high-quality production. This study examined photosynthetic characteristics by the phylloclade levels of S. truncata in a growth chamber and a greenhouse for use of night CO₂ enrichment. The CO₂ uptake rate of the S. truncata's top phylloclade in a growth chamber exhibited a C₃ pattern, and the second phylloclade exhibited a C₃-CAM pattern. The CO₂ uptake rate of the top phylloclade in a greenhouse showed a negative value both day and night, but those of the second phylloclade exhibited a CAM pattern. The stomatal conductance and water-use efficiency (WUE) of S. truncata at both the top and second phylloclades were higher in a growth chamber than in a greenhouse. The WUE of S. truncata in a growth chamber and a greenhouse was higher at the second phylloclade, which is a CAM pattern compared with those of the top phylloclade. The daily total net CO₂ uptake of S. truncata was higher in a growth chamber than in a greenhouse. The daily total net CO₂ uptake of S. truncata at the second phylloclade had the highest value of 155 mmol·m^-2·d^-1 in a growth chamber. The night total CO₂ uptake of S. truncate at the second phylloclade was 3-fold higher in a growth chamber than in a greenhouse. S. truncata's second phylloclade exhibited a CAM pattern that uptake CO₂ at night, and the second phylloclade, was more mature than the top phylloclade. A multi-flowering cactus S. truncata 'Pink Dew' efficiently uptake night surplus CO₂ in the proper environmental condition with matured phylloclade.

• Mass Spectrometry Letters
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• v.10 no.1
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• pp.27-31
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• 2019

In this article, the properties of ${CO_2}^+(CO_2)_n$ clusters in a Paul ion trap have been investigated using mass-selective instability mode which conducted by chosen precursor ions, mainly $Ar^+$ and ${CO_2}^+$ produced by a mixture of Ar and $CO_2$. Exposure of ${CO_2}^+$ ions to $CO_2$ molecules, lead to the formation of ${CO_2}^+(CO_2)_n$ clusters. Here, Ar gas react as a buffer gas and lead to form ${CO_2}^+(CO_2)_n$ cluster by collisional effect.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.3
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• pp.280-285
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• 2005

The method of chemical absorption has been presented to separate and recover acid gases like $CO_2\;and\;H_2S$. But, this method has some problems such as loss of valuable amine and operational problems (forming, corrosion and fouling) by degradation. In this study, we investigated the degradation characteristics of aqueous AMP solution containing additives such as HMDA, MDEA and piperazine. The degradation was affected by temperature and process time. AMP solution absorbing $CO_2\;and\;H_2S$ was degraded 105% and 23% more than pure AMP at $120^{\circ}C$ respectively. In addition, all the additives were degraded significantly as the temperature increased. The order of the degraded amount of additives mixed in the AMP solution containing absorbed $CO_2$ was as followings : HMDA > piperazine > MDEA.