• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.451-454
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• 2009

Production and application of biodiesel are expected to grow steadily in the coming years and thus output of its by-product, crude glycerin, will accordingly increase as well. In the present study, gasification of biodiesel by-product as a renewable energy was performed in an entrained flow gasifier to investigate the gasification performance with the operating conditions. Crude glycerin shows a high heating value of 6,000 kcal/kg and low ash and sulphur content. Gasification was conducted in a temperature range of $950\;{\sim}\;1500\;^{\circ}C$. The variation of syngas composition with excess air ratio of 0.17 ~ 0.7 for air or oxygen as a gasification agent was investigated. From the results, syngas heating value, carbon conversion and cold gas efficiency of more than $2500\;kcal/Nm^3$, 95% and 65% were achieved, respectively. The temperature dependency of syngas composition, carbon conversion, and cold gas efficiency shows a similar tendency to excess air ratio at the temperature corresponding to the excess air ratio. The $H_2/CO$ ratio of the product gas was varied from 1.25 to 0.7 with the excess air ratio and this gas composition was favorable for DME synthesis. The optimum excess air ratio for gasification of biodiesel by-product was evaluated to be an approximately 0.35 to 0.4. The present results indicate that crude glycerin can be utilized as a feedstock for gasification to make syngas.

• Macromolecular Research
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• v.16 no.5
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• pp.446-456
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• 2008

A recent theoretical approach based on the coupling of both the Flory-Huggins (FH) and the Association Equilibria thermodynamic (AET) theories was modified and adapted to study the miscibility properties of a multi-component system formed by two polymers (a proton-donor and a proton-acceptor) and a proton-acceptor solvent, named copolymer(A)/solvent(B)/polymer(C). Compatibility between polymers was mainly attained by hydrogen-bonding between the hydroxyl group on the phenol unit of the poly(styrene-co-vinyl phenol) (PSVPh) and the carbonyl group of the biodegradable and environmentally friendly poly(3-hydroxybutyrate) (PHB). However, the self-association of PSVPh and specific interactions between the PSVPh and the H-acceptor group (an ether oxygen atom) of the epichlorohydrin (ECH) solvent were also established in a lower extension, which competed with the polymer-polymer association. All the binary specific interactions and their dependence with the system composition as well as with the copolymer content were evaluated and quantified by means of two excess functions of the Gibbs tree energy, ${\Delta}g_{AB}$ and ${\Delta}g_{AC}$. Experimental results from fluorescence spectroscopy were consistent with the theoretical simulations derived with the model, which could also be applied and extended to predict the miscibility in solution of any polymer blend with specific interactions.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.1
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• pp.74-82
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• 2004

Planar laser-induced fluorescence(PLIF) has been widely used to obtain two dimensional fuel distribution. Acetone PLIF is chosen because fluorescence signal from acetone as a fluorescent tracer is less sensitive to oxygen quenching than other dopants. Acetone PLIF is applied to measure quantitative air excess ratio distribution in an engine fueled with LPG. Acetone is excited by KrF excimer laser (248nm) and its fluorescence image is acquired by ICCD camera with a cut-off filter to suppress Mie scattering from the laser light. For the purpose of quantifying PLIF signal, an image processing method including the correction of laser sheet beam profile is suggested. Raw images are divided by each intensity of laser energy and profile of laser sheet beam. Inhomogeneous fluorescence images scaled with the reference data, which is taken by a calibration process, are converted to air excess ratio distribution. This investigation shows instantaneous quantitative measurement of planar air excess ratio distribution for gaseous fuel.

• Journal of Soil and Groundwater Environment
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• v.15 no.6
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• pp.114-121
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• 2010

Oxygen sensitivity and substrate requirement have been known as possible reasons for the intricate growth of Dehalococcoides spp. and limiting factors of for routinely applying bioaugmentation using anaerobic Dehalococcoides-containing microbes for remediating chlorinated organic compounds. To explore the effect of the short-term exposure of the short-term exposure of oxygen on Dehalococcoides capability, dechlorination performance, and hydrogen production fermentation from formate, an anaerobic reductive dechlorination mixed-culture (Evanite culture) including dehalococcoides spp. was in this study. In the results, once the mixed-culture were exposed to oxygen, trichloroethylene (TCE) degradation rate decreased and it was not fully recovered even addition of excess formate for 40 days. In contrast, hydrogen was continuously produced by hydrogen-fermentation process even under oxygen presence. The results indicate that although the oxygen-exposed cells cannot completely dechlorinate TCE to ethylene (ETH), hydrogen fermentation process was not affected by oxygen presence. These results suggest that dechlorinating microbes may more sensitive to oxygen than fermenting microbes, and monitoring dechlorinators activity may be critical to achieve an successful remediation of a TCE contaminated-aquifer through bioaugmentation using Dehalococcoides spp..

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.263-266
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• 2000

Effects of excess Pb(50 mole ％) on the crystallization properties of amorphous PZT thin films on the glass substrates by post-annealing in oxygen ambient were investigated to lower the crystallization temperature of the PZT thin films with a single perovskite phase. The PZT thin films(350nm) were prepared on Pt/Ti/corning glass(1737) substrates. The PZT thin films and bottom electrode were deposited by RF magnetron sputtering. Crystallization properties of PZT thin films were strongly dependent on RTA(Rapid Thermal Annealing) temperature. We were able to obtain a perovskite structure of PZT at 600$^{\circ}C$ for 10min. After thermal treatments were done, electrical properties such as I-V, P-E, and fatigue were measured.

• Microbiology and Biotechnology Letters
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• v.20 no.3
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• pp.348-354
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• 1992

In order to improve the productivity of invertase by recombinant Saccharomyces cerevisiae containing SUC2 gene, the effect of amino acids and dissolved oxygen concentration on the gene expression was investigated. Optimal concentrations of leucine and histidine for cell growth and cloned gene expression were 0.03 gig and 0.04 gig, respectively, expressed as the ratio of amino acid/glucose. The lack or excess of leucine and histidine has inhibitory effect on cell growth and invertase expression. In batch culture, the less aeration was, the higher invertase activity was. In continuous culture at a dilution rate of 0.09 h 1 with controlled dissolved oxygen tension, invertase activity increased dramatically at DOT levels below 5% air saturation, and a maximum activity of 215.54 KUlg cell was obtained under unaerated condition.

• BMB Reports
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• v.48 no.6
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• pp.301-302
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• 2015

Hypoxia is associated with many pathological conditions as well as the normal physiology of metazoans. We identified a lactate-dependent signaling pathway in hypoxia, mediated by the oxygen- and lactate-regulated protein NDRG family member 3 (NDRG3). Oxygen negatively regulates NDRG3 expression at the protein level via the PHD2/VHL system, whereas lactate, produced in excess under prolonged hypoxia, blocks its proteasomal degradation by binding to NDRG3. We also found that the stabilized NDRG3 protein promotes angiogenesis and cell growth under hypoxia by activating the Raf-ERK pathway. Inhibiting cellular lactate production abolishes NDRG3-mediated hypoxia responses. The NDRG3-Raf-ERK axis therefore provides the genetic basis for lactate-induced hypoxia signaling, which can be exploited for the development of therapies targeting hypoxia-induced diseases in addition to advancing our understanding of the normal physiology of hypoxia responses. [BMB Reports 2015; 48(6): 301-302]

• International Journal of Aeronautical and Space Sciences
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• v.1 no.1
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• pp.62-69
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• 2000

Present study deals with performance analysis of an inert gas generator (IGG) which can be used as effective means to suppress fire. The IGG uses a turbo-jet engine to generate inert gas for fire extinguishing. It is generally known that a less degree of oxygen content in the product of combustion will increase the effectiveness of fire extinguishing. An inert gas generator system with water injection has advantages of suffocating and cooling effects that are very important factors for fire extinguishing. Some aspects of influencing parameters, such as, air excess coefficient, compressor pressure ratio, air temperature before combustion chamber, gas temperature after combustion chamber, mass flow rate of water injection etc. on the performance of IGG system are investigated.

• Computers and Concrete
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• v.16 no.3
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• pp.487-502
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• 2015

This study investigated particle expansion in basic oxygen furnace slag (BOF) and desulfurization slag (DSS) after heat curing by using the volume method. Concrete hydration was accelerated by heat curing. The compressive strength, ultrasonic pulse velocity, and resistivity of the concrete were analyzed. Maximum expansion occurred in the BOF and DSS samples containing 0.30-0.60 mm and 0.60-1.18 mm particles, respectively. Deterioration was more severe in the BOF samples. In the slag aggregates for the complete replacement of fine aggregate, severe fractures occurred in both the BOF and DSS samples. Scanning electron microscopy revealed excess CH after curing, which caused peripheral hydration products to become extruded, resulting in fracture.

• Current Applied Physics
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• v.18 no.11
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• pp.1447-1450
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• 2018

The electron spin resonance (ESR) detects point defect of the In-Ga-Zn oxide (IGZO) like singly ionized oxygen vacancies and excess oxygen, and get spin density as a parameter of defect state. So, we demonstrated the spin density measurement of the IGZO film with various deposition conditions and it has linear relationship. Moreover, we matched the spin density with the total BTS and the threshold voltage ($V_{th}$) distribution of the IGZO thin film transistors. The total BTS ${\Delta}V_{th}$ and the $V_{th}$ distribution were degraded due to the spin density increases. The spin density is the useful indicator to predict $V_{th}$ instability of IGZO TFTs.