• Journal of the Korea Organic Resources Recycling Association
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• v.8 no.2
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• pp.71-76
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• 2000

The biological carbon dioxide fixation using microalgae has been known as an effective carbon dioxide reduction technology. With many environmental factors influencing microalgal productivity, the desirable cultivation factors were investigated using a green alga, Euglena gracilis. It has the high protein and vitamin E to be used as fodder. In batch culture with a photobioreactor, initial pH, temperature, carbon dioxide concentration and light intensity in the optimum cultivation condition were 3.5, $27^{\circ}C$,5-10% and $520{\mu}mol/m^2/s$, respectively. After that, the optimum hydraulic retention time (HRT for the continuous cultivation was 4 days at carbon dioxide concentration of 10%. In this condition, the final dry cell weight was 1.2g/l.

• Bulletin of the Korean Chemical Society
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• v.25 no.12
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• pp.1807-1811
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• 2004

Supercritical fluid chromatography (SFC) was considered for separating racemic ibuprofen. The chromatographic column (3.9 ${\times}$ 150 mm) was packed with Kromasil$^{\circledR}$ CHI-TBB, and the mobile phase was supercritical carbon dioxide with modifier of IPA. The experimental variables were the content of IPA, and temperature and pressure of supercritical mobile phase. To determine the separation condition, the empirical equation of retention factor and resolution was proposed. In the case of retention factor, the empirical equation was in the form, $k\;=\;a{\rho}\;+b/F\;+\;c\;({\rho}/F)\;+\;d$. The empirical equation for resolution was proposed as a linear form, $R\;=\;a{\rho}\;+\;bF\;+\;c$.

• Journal of Radiation Protection and Research
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• v.28 no.3
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• pp.207-213
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• 2003

Carbon-14 is one of the major radionuclides released by CANDU Nuclear Power Plants(NPPs). It is almost always emitted as gas through the stack. From CANDU NPPs about 95% of all carbon-14 is released as carbon dioxide. Carbon-14 is a low energy beta emitter which, therefore, gives only a small skin dose from external radiation. As carbon dioxide Is physiologically rather inert gases for man's metabolism, the inhalation dose is probably less than 1 % of the ingestion dose. But this source of carbon-14, formed in a closed, nor-oxidative environment, was subsequently released into the workplace as an insoluble particulate when these systems were opened lip for re-tubing at CANDU NPPs. As a part of the improvement of dosimetry program at Wolsong Nuclear Power Plants, the carbon-14 metabolism based on references was investigated and studied to setup the internal dosimetry program due to inhalation of carbon-14.

• 한국전기화학회:학술대회논문집
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• 1999.11a
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• pp.137-146
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• 1999

The rechargeable alkaline manganese dioxide(RAM)battery system has reached a performance level that enables the consumer to utilize RAM for practically all applications where currently single use cells(alkaline manganese, zinc-carbon)are being used. In addition, it can replace nickel-cadmium and nickel-metal hydride cells in low to medium power applications with much improved charge retention at higher operating temperatures and in intermittent use and works well with solar charging. A review is given on RAM cell performance as well as a comparison to competing rechargeable technologies. Potential new possibilities in the field of OEM(original equipment manufacturer) applications are discussed.

• Korean Journal of Materials Research
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• v.30 no.1
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• pp.14-21
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• 2020

Carbon supports for dispersed platinum (Pt) electrocatalysts in direct methanol fuel cells (DMFCs) are being continuously developed to improve electrochemical performance and catalyst stability. However, carbon supports still require solutions to reduce costs and improve catalyst efficiency. In this study, we prepare well-dispersed Pt electrocatalysts by introducing titanium dioxide (TiO₂) into biomass based nitrogen-doped carbon supports. In order to obtain optimized electrochemical performance, different amounts of TiO₂ component are controlled by three types (Pt/TNC-2 wt%, Pt/TNC-4 wt%, and Pt/TNC-6 wt%). Especially, the anodic current density of Pt/TNC-4 wt% is 707.0 mA g^-1_pt, which is about 1.65 times higher than that of commercial Pt/C (429.1 mA g^-1_pt); Pt/TNC-4wt% also exhibits excellent catalytic stability, with a retention rate of 91 %. This novel support provides electrochemical performance improvement including several advantages of improved anodic current density and catalyst stability due to the well-dispersed Pt nanoparticles on the support by the introduction of TiO₂ component and nitrogen doping in carbon. Therefore, Pt/TNC-4 wt% may be electrocatalyst a promising catalyst as an anode for high-performance DMFCs.

• Applied Biological Chemistry
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• v.35 no.1
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• pp.55-63
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• 1992

The essential oil of Korean ginger(Zingiber officinale Roscoe) was isolated by liquid carbon dioxide extraction method and fractionated into one hydrocarbon fraction and two oxygenated hydrocarbon fractions by using silica gel column chromatography. The compositions of the resulting oils were investigated by GC and GC-MS spectrometry. Out of 102 identified compounds, 44 were identified by comparing GC retention time and mass spectral data with authentic samples and 58 were tentatively identified according to mass spectral data only. The major compounds of hydrocarhon fraction were $zingiberene,\;{\beta}-sesquiphellandrene,\;{\gamma}-bisabolene,\;{\gamma}-cardinene,\;ar-curcumene$, and those of oxygenated hydrocarbon fractions wee geranal, sesquisabinene hydrate, borneol and zingiberenol. The major compounds of ginger oil were zingiberene, $citronellol+{\beta}-sesquiphellandrene,\;geranial,\;{\gamma}-bisabolene\;and\;ar-curcumene+geranyl\;acetate$, and ginger oil contained higher amounts of sesquiterpene hydrocarbons. The yield of extract was 6.96%.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.7
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• pp.1080-1084
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• 1999

Carbon (C) and nitrogen (N) balance technique was used to determine energy balance in Rhode Island Red (RIR) and White Leghorn (WL) laying hens fed maize-and broken rice (BR)- based diets. Carbon and nitrogen intake and outgo were determined for three days on ad libitum fed diets followed by 2/3 of ad libitum intake for next three days. Carbon analysis was done by using four 'U' tubes in which carbon dioxide released during bomb calorimetry was absorbed on drierite in tube 1 and 2 whereas tube 3 and 4 contained sodalime self indicating granule. Carbon in $CO_2$ was determined by an open circuit respiration system. Energy retention (E, kcal) was calculated as E = 12.386 C (g) - 4.631 N (g). By regressing metabolisable energy (ME) intake on energy balance, maintenance ME requirement of RIR was 128 whereas, that of WL hens was $144kcal/kg\;W^{0.75}/d$. Effciency of utilization of ME for maintenance from BR-based diet in RIR hens was equal but in WL hens it was 11% less than maize-based diet.

• Journal of the Korea Organic Resources Recycling Association
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• v.9 no.1
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• pp.73-78
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• 2001

The biological carbon dioxide fixation using microalgae and photo-bioreactor has been known as an effective carbon dioxide reduction technology. As algae has many other environmental factor for its growth, the desirable cultivation factors were investigated using a green alga, Euglena gracilis Z. In this study, Euglena gracilis Z showed good $CO_2$ fixation ability in high $CO_2$ concentration of 10-20% and it contained the high protein and vitamin E enough to be used as fodder. For the mass cultivation, the continuous and semi-continuous cultivation methods were employed. The optimum hydraulic retention time (HRT) for the continuous cultivation was 4 days at carbon dioxide concentration of 10%. In this condition, the final cell number was $3.57{\times}10^6/m{\ell}$. The growth of Euglena gracilis Z increased according to the light intensity.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.7
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• pp.394-399
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• 2016

The silicon dioxide ($SiO_2$) was deposited using various gas as oxygen and nitrous oxide ($N_2O$) in nowadays. In order to improve electrical characteristics and the interface state density ($D_{it}$) in low temperature, It was deposited with carbon dioxide ($CO_2$) and silane ($SiH_4$) gas by inductively coupled plasma chemical vapor deposition (ICP-CVD). Each $D_{it}$ of $SiO_2$ using $CO_2$ and $N_2O$ gas was $1.30{\times}10^{10}cm^{-2}{\cdot}eV^{-1}$ and $3.31{\times}10^{10}cm^{-2}{\cdot}eV^{-1}$. It showed $SiO_2$ using $CO_2$ gas was about 2.55 times better than $N_2O$ gas. After 10 years when the thin film was applied to metal/insulator/semiconductor(MIS)-nonvolatile memory(NVM), MIS NVM using $SiO_2$($CO_2$) on tunneling layer had window memory of 2.16 V with 60% retention at bias voltage from +16 V to -19 V. However, MIS NVM applied $SiO_2$($N_2O$) to tunneling layer had 2.48 V with 61% retention at bias voltage from +20 V to -24 V. The results show $SiO_2$ using $CO_2$ decrease the $D_{it}$ and it improves the operating voltage.

• Advances in environmental research
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• v.7 no.2
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• pp.73-85
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• 2018

The anaerobically digestion and agricultural application of organic wastes was conducted using food wastes and cow dung. Twenty kilograms each of the feed stocks was added into two 30 liters-capacity batch digesters. The anaerobic digestion was carried out within a temperature range of $25-31^{\circ}C$ for a retention time of 51 days. The results showed a cumulative gas yield of 5.0 bars for food waste and no gas production for cow dung within the retention time. Bacteria such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Proteus vulgaris and Clostridium sp were isolated. Fungi isolated included Aspergillus niger, Aspergillus nidulan, Trichophyton rubrum and Epidermophyton flocossum. The non-dispersive infrared (NDIR) analysis of the biogas produced confirmed that the gas consisted of $CH_4$, $CO_2$ and $H_2$. Statistical analysis revealed there was no significant correlation between temperature and biogas produced from the organic wastes (r= 0.177, p = 0.483).The organic wastes from the biogas production process stimulated maize growth when compared to control (soil without organic waste) and indicated maximum height. The study therefore reveals that food waste as potential substrates for biogas production has a moderate bio-fertilizer potential for improving plant growth and yield when added to soil.