• Journal of the Korean Society of Combustion
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• v.11 no.3
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• pp.26-35
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• 2006

This work forcus on the development of gas sensor that measure the concentrations of exhaust gas using diode laser, Each diode laser for exhaust gas measurement is set to work at near-IR using both DA and WMS methods. Also use of fiber-coupled optical elements makes such a sensor rugged and easy to align. The results showed that gas concentrations of $O_2$, CO, $CO_2$, NO are accurately measured within ${\pm}2%$ error. The application of WMS method increased the beam intensity 2-3 times higher than DA method. It were experimentally compared WMS (Wavelength Modulation Spectroscopy) with DA (Direct Absorption) for the accuracy.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.578-581
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• 2001

A treatability study was conducted using a hydrocarbon-contaminated soil for the oPtimization of bioremediation strategy best fit to a given set of contamination. The applicability of nutrients, biosurfactant, and oil-degrading microorganisms were examined by monitoring $CO_2$ evolution and oil degradation The addition of inorganic nutrients in the form of slow released fertilizer accelerated the initial rate of $CO_2$ evolution by a factor of 3. The application of oil-degrading microorganisms did not significantly increased $CO_2$ evolution or biodegradation efficiency. Application of a commercial biosurfactant was most effect in terms of the total $CO_2$ evolution and the oil degradation rate. The results indicate that $CO_2$ evolution measurement was found to be a simple and reliable countermeasure of crude oil hydrocarbon mineralization for the rapid determination of the best-fit bioremediation strategy.

• Fibers and Polymers
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• v.6 no.4
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• pp.284-288
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• 2005

Poly(ethylene terephthalate) was annealed at different temperature and pressure of supercritical carbon dioxide $(CO_2)$ using samples quenched from the melt. Crystallization and molecular relaxation behavior due to $CO_2-annealing$ of samples were investigated using differential scanning calorimetric and dynamic mechanical measurements. The glass transition and crystallization temperatures significantly decreased with increasing temperature and pressure of $CO_2$. The dynamic mechanical measurement of samples annealed at $150^{\circ}C$ in supercritical $CO_2$ showed three relaxation peaks, corresponding to existence of different amorphous regimes such as rigid, intermediate, and mobile domains. As a result, the mobile chains were likely to facilitate crystallization in supercritical state. It also led to the decreased modulus of $CO_2-annealed$ samples with increasing pressure.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.100-101
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• 2018

Environmental problems caused by air pollution have been considered as serious critical issues in global perspectives. Controlling greenhouse gases has become one of the major environmental problems in construction fields as well. However, similar studies were mainly focused on suggestion of various methodologies for measuring CO₂ emissions of construction equipment and calculating emissions. This study aims to analyze the correlation between the CO₂ emissions and RPMs of equipment by the construction process based on row data collected from construction equipment actually operated in job sites. This study allows site personnels to determine the amount of emitted CO₂ under particular construction equipment under specific conditions during the targeted construction operations. The research findings expect to be used as fundamental informations for establishing environment-friendly construction operation planning.

• Journal of the Korean housing association
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• v.9 no.1
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• pp.143-152
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• 1998

This study aims to suggest ventilation design data for Public Entertainment Facilities in relation to Indoor Air Quality. The concentration of indoor air pollution such as CO, CO2, RH, Radon, HCHO, TSP was investigate, and the reguired ventilation rate of Public Rooms was calculated. As resuits of this study, the following conclusion could be obtained. Field measurement of P.E.F reveals that the concentration of CO2 was mist polluted and higher than IAQ standard, while that of other pollutats did not exceed the standard. In underground the concentration of CO2 increased 1130ppm(2 persons) 2170ppm(4 persons) 1970ppm(6 persons). The CO2 pollution was serions problem in underground more than second floor, in only exhaust ventilation system more than exhaust and supply system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.9
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• pp.863-872
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• 2005

It is important to control indoor environment for influence on health and comfort of occupants in large-sized discount stores. On the other hand large-sized discount stores have a large number of visitors, vestibules, open spaces, high energy consumption and increasing of outside air intake. This study aims to offer the design data of building services system that can save energy and control environment through field measurement selecting two large-sized discount stores. Indoor environment factors such as temperature, relative humidity, air velocity and concentrations of $CO_2$, CO gas and TSP were measured and evaluated. In each case of $CO_2$, and CO gas, its maximum values were 2,800 ppm and 20 ppm. So proper strategy for the indoor air quality is indispensable in this type of building. Dry bulb temperature varies from $18^{\circ}C$ to $28^{\circ}C$ according to a measuring point and time. From this results, it is inferred these buildings had excessive equipment capacity. In terms of economical and environmental points, these data will be utilized to the design of HVAC system of retail facilities.

• Korean Journal of Soil Science and Fertilizer
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• v.50 no.6
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• pp.554-561
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• 2017

Under the projected global warming, release of carbon as $CO_2$ through soil organic matter decomposition is expected to increase. Therefore, accurate measurement of $CO_2$ released from soil is crucial in understanding the soil carbon dynamics under increased temperature conditions. Sodium hydroxide (NaOH) traps are frequently used in laboratory soil incubation studies to measure soil respiration rate, but decreasing $CO_2$ gas solubility with increasing temperature may render the reliability of the method questionable. In this study, the influences of increasing temperature on the $CO_2$ capture capacity of NaOH traps were evaluated under $5{\sim}35^{\circ}C$ temperature range at $10^{\circ}C$ interval. Two closed-chamber experiments were performed where NaOH traps were used to capture $CO_2$ either released from acidified $Na_2CO_3$ solution or directly injected into the chamber. The sorption of ambient $CO_2$ within the incubators into NaOH traps was also measured. The amount $CO_2$ captured increased as temperature increased within 2 days of incubation, suggesting that increased diffusion rate of $CO_2$ at higher temperatures led to increases in $CO_2$ captured by the NaOH traps. However, after 2 days, over 95% of $CO_2$ emitted in the emission-absorption experiment was captured regardless of temperature, demonstrating high $CO_2$ absorption efficiency of the NaOH traps. Thus, we conclude that the influence of decreased $CO_2$ solubility by increased temperatures is negligible on the $CO_2$ capture capacity of NaOH traps, supporting that the use of NaOH traps in the study of temperature effect on soil respiration is a valid method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.821-823
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• 2003

We have developed the evaluation program using LabVIEW for the high power laser measurement system.

• Journal of Environmental Science International
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• v.16 no.12
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• pp.1431-1437
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• 2007

Cobalt titanates($CoTiO_x$), such as $CoTiO_3$ and $Co_2TiO_4$, have been synthesized via a solid-state reaction and characterized using X-ray diffraction(XRD) and X-ray photoelectron spectroscopic(XPS) measurement techniques, prior to being used for continuous wet trichloroethylene(TCE) oxidation at $36^{\circ}C$, to support our earlier chemical structure model for Co species in 5 wt% $CoO_x/TiO_2$(fresh) and(spent) catalysts. Each XRD pattern for the synthesized $CoTiO_3$ and $Co_2TiO_4$ was very close to those obtained from the respective standard XRD data files. The two $CoTiO_x$ samples gave Co 2p XPS spectra consisting of very strong main peaks for Co $2p_{3/2}$ and $2p_{1/2}$ with corresponding satellite structures at higher binding energies. The Co $2p_{3/2}$ main structure appeared at 781.3 eV for the $CoTiO_3$, and it was indicated at 781.1 eV with the $Co_2TiO_4$. Not only could these binding energy values be very similar to that exhibited for the 5 wt% $CoO_x/TiO_2$(fresh), but the spin-orbit splitting(${\Delta}E$) had also no noticeable difference between the cobalt titanates and a sample of the fresh catalyst. Neither of all the $CoTiO_x$ samples were active for the wet TCE oxidation, as expected, but a sample of pure $Co_3O_4$ had a good activity for this reaction. The earlier proposed model for the surface $CoO_x$ species existing with the fresh and spent catalysts is very consistent with the XPS characterization and activity measurements for the cobalt titanates.

• Journal of Magnetics
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• v.11 no.1
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• pp.16-19
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• 2006

$2-\mu{m}$ thick GaN epilayer was prepared, and 80 KeV $Co^{-}$ ions with a dose of $3X10^{16}\;cm^{-2}$ were implanted into GaN at $350^{\circ}C$. The implanted samples were post annealed at $700^{\circ}C$. We have investigated the magnetic and structural properties of Co ion-implanted GaN by various measurements. HRXRD results did not show any peaks associated with second phase formation and only the diffraction from the GaN layer and substrate structure were observed. SIMS profiles of Co implanted into GaN before and after annealing at $700^{\circ}C$ have shown a projected range of $\sim390\AA$ with 7.4% concentration and that there is little movement in Co. AFM measurement shows the form of surface craters for $700^{\circ}C$-annealed samples. The magnetization curve and temperature dependence of magnetization taken in zero-field-cooling (ZFC) and field-cooling (FC) conditions showed the features of superparamagnetic system in film. XPS measurement showed the metallic Co 2p core levels spectra for $700^{\circ}C$-annealed samples. From this, it could be explained that magnetic property of our films originated from Co magnetic clusters.