• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.9
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• pp.789-795
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• 2016

Laser-induced combustions and explosions generated by high laser irradiances were explored by Laser-Induced Breakdown Spectroscopy (LIBS). The laser used for target ablation is a Q-switched Nd:YAG laser with 7 ns pulse duration at wavelength of 1064 nm laser energies from 40 mJ to 2500 mJ ($6.88{\times}10^{10}-6.53{\times}10^{11}W/cm^2$). The plasma light source from aluminum detected by the echelle grating spectrometer and coupled to the gated ICCD(a resolution (${\lambda}/{\Delta}{\lambda}$) of 5000). This spectroscopic study has been investigated for obtaining both the atomic/molecular signals of aluminum-oxygen and the calculated ambient condition such as plasma temperature and electron density. The essence of the paper is observing specific electron density ratio which can support the processes of chemical reaction and combustion between ablated aluminum plume and oxygen from air by inducing high laser energy.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.325-326
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• 2001

오존은 태양광선의 존재 하에 질소산화물과 VOCs가 관련하여 발생하는 생성물이다. 대기중의 VOCs 는 히드록실 라디칼(hydroxyl radical, OHㆍ)과 같은 자유 라디칼(free radical)과 반응하여 하이드로퍼옥시 라디칼(hydroperoxy radical, HO$_2$ㆍ)과 알킬 퍼옥시 라디칼(alkyl peroxy radical, RO$_2$ㆍ)을 생성해 낸다. 이 퍼옥시 라디칼들은 NO를 NO$_2$ㆍ로 산화시키며 또한 히드록실 라디칼을 재생하며 이 히드록실 라디칼은 다시 VOCs와 반응한다. 그리고, 이때 산화된 NO$_2$는 햇빛에 의해 NO와 자유산소원자(free oxygen atom)로 광분해 되는데, 여기서 생성된 자유산소인자는 산소분자와 반응하여 오존을 생성한다. (중략)

• Applied Chemistry for Engineering
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• v.5 no.4
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• pp.609-615
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• 1994

Partial oxidation of ethylene over 10wt% $Ag/{\alpha}-Al_2O_3$ catalyst was studied with a pulse reactor which was connected directly to a G. C. When ethylene was injected after oxygen injection at the temperature where molecular adsorption of oxygen is difficult ethylene oxide was evolved. From the results, it is suggested that adsorbed atomic oxygen is related with the evolution of ethylene oxide. The selectivity to ethylene oxide decreased with the decrease of the amounts of adsorbed oxygen and bulk oxygen. Ethylene oxide was either decomposed to ethylene and adsorbed oxygen or isomerized to acetaldehyde. However, the isomerization of ethylene oxide to acetaldehyde was strongly suppressed by the preadsorbed oxygen.

• Applied Chemistry for Engineering
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• v.3 no.1
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• pp.64-71
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• 1992

New type dioxygen bridged complexes of palladium were prepared by using $KO_2$ as a source of superoxide ion($O_2{^-}$). The method is completely different from the traditional one which has adopted the oxidative addition of molecular oxygen to prepare the dioxygen complexes. This reaction proceeds via nucleophilic displacement followed by electron transfer reaction. Three new type dioxygen complexes of palladium having amine ligands were prepared and characterized by the application of the reaction of $O_2{^-}$.

• Journal of Yeungnam Medical Science
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• v.15 no.1
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• pp.97-113
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• 1998

The sympathoadrenal system plays an important role in homeostasis in widely varing external environments. Conflicting findings, however, have been reported on its response to hypoxia. We investigated the effect of hypoxia on the sympathoadrenal system in dogs under halothane anesthesia by measuring levels of circulating catecholamines in response to graded hypoxia. Ten healthy mongreal dogs were mechanically ventilated with different hypoxic gas mixtures. Graded hypoxia and reoxygenation were induced by progressively decreasing the oxygen fraction in the inhalation gas mixture from 21%(control) to 15%, 10% and 5% at every 5 minutes, and then reoxygenated with 60% oxygen. Mean arterial pressure, central venous pressure and mean pulmonary arterial pressure were measured directly using pressure transducers. Cardiac output was measured by the thermodilutional method. For analysis of blood gas, saturation and content, arterial and mixed venous blood were sampled via the femoral and pulmonary artery at the end of each hypoxic condition. The concentration of plasma catecholamines was determined by radioenzymatic assay. According to the exposure of graded hypoxia, not only did arterial and mixed venous oxygen tension decreased markedly at 10% and 5% oxygen, but also arterial and mixed venous oxygen saturation decreased significantly. An increased trend of the oxygen extraction ratio was seen during graded hypoxia. Cardiac output, mean arterial pressure and systemic vascular resistance were unchanged or increased slightly. Pulmonary arterial pressure(PAP) and pulmonary vascular resistance(PVR) were increased by 55%, 76% in 10% oxygen and by 82%, 95% in 5% oxygen, respectively(p<0.01). The concentrations of plasma norepinephrine, epinephrine and dopamine increased by 75%, 29%, 24% in 15% oxygen and by 382%, 350%, 49% in 5% oxygen. These data suggest that the sympathetic nervous system was activated to maintain homeostasis by modifying blood flow distribution to improve oxygen delivery to tissues by hypoxia, but hemodynamic changes might be blunted by high concentration of nitrous oxide except PAP and PVR. It would be suggested that hemodynamic changes might not be sensitive index during hypoxia induced by high concentration of nitrous oxide exposure.

• Journal of the KSME
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• v.31 no.7
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• pp.652-656
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• 1991

일반적으로 로켓 추진기관이라고 하면 외부로부터의 산소 공급없이, 추진제라고 불리는 물질이 연소할 때 발생하는 고온 고압의 연소가스를 고속으로 노즐로 통과시켜 추력을 얻는기관을 말 한다. 연소는 산소와의 화합반응이 급격히 일어날 때 일어나는 현상이므로 외부로부터 산소공 급이 없다는 것은, 추진제 자체에서 산소공급이 가능하다는 것을 의미한다. 즉, 추진제는 그 자 체가 흔히 말하는 연료성분과 산소를 공급할 수 있는 산소화합물을 같이 묶어둔 물질이어야 한다. 그러나 지구를 둘러싸고 있는 대기에는 산소가 20%나 포함되어 있으며, 이 무궁무진한 산소를 이용하지 않는다는 것은 여러 면에서 손실임을 쉽게 알 수 있을 것이다. 그럼에도 불구 하고 이를 이용하지 못하고 있었음은 그 나름대로의 어려움이 있었기 때문일 것이다. 그러나 인간의 노력과 연구로 불가능했던 많은 사실도 가능하게 된 것이 헤아릴 수 없이 많아지고 있음 또한 주지의 사실이다. 로켓 추진기관 분야에서도 순수 연료 성분만을 로켓에 탑재하고 산소는 흡입되는 대기중의 것을 이용하자는 것이 새로운 연구분야로 각광을 얻고 있으며, 실제로 이러한 방법이 실용화되고 있다. 이와 같이 흡입공기를 산소원으로 하는 추진기관을 총칭 램제트 추진 기관이라고 한다.

• Applied Chemistry for Engineering
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• v.22 no.3
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• pp.261-265
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• 2011

The sterilization effects of atmospheric pressure plasma with the mixture of argon and oxygen were analyzed. The plasma reactor with the shape of dielectric barrier discharge produced the uniform distribution of glow discharge and generated ozone gas effectively according to the various process parameters. The sterilization for E. coli was affected by power, oxygen ratio in the mixture gas, treatment time and distance between reactor and sample. The concentration of ozone was a major source for the sterilization of E. coli, which was enhanced by the increase of power and oxygen ratio. In this study, the effect of atmospheric pressure plasma treatment for the sterilization was confirmed and its result can deliver the atmospheric pressure plasma treatment as the novel sterilization method instead of conventional methods.

• Korean Journal of Food Science and Technology
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• v.36 no.4
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• pp.580-585
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• 2004

Respiration of 'Fuyu' persimmon (Diospyros kaki) fruits were measured in terms of oxygen consumption rate and carbon dioxide evolution by closed system experiments at 0, 5, and $20^{\circ}C$. Enzyme kinetics-based respiration model was used to describe respiration rate as function of $O_2\;and\;CO_2$ gas concentrations $(R=V_m[O_2]/K_m+(1+[CO_2]/K_i)[O_2])$, and Arrhenius equation was applied to analyze temperature effect. $V_m\;and\;K_m$ increased, while $K_i$ decreased, with increasing temperature. $K_m\;of\;O_2$ consumption was greater than that of $CO_2$ evolution at equal temperature. Inhibitory effect of reduced $O_2$ level on $O_2$ consumption was more prominent than that on $CO_2$ evolution. Activation energy of respiration decreased with reduced $O_2$ and elevated $CO_2$ concentrations. Activation energy of $CO_2$ evolution was greater than that of $O_2$ consumption. Permeable package experiments verified respiration model parameters by showing good agreement between predicted and experimental gas concentrations in package.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.7
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• pp.764-769
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• 2006

In the electrokinetic(EK) process, oxygen production by electrolysis was proportional to current density. The dissolved oxygen (DO) concentration in anode tank and bioreactor increased with the circulation rate of electrolyte. The bacterial population in bioreactor rapidly increased by the supplement of current, but the DO concentration deceased by the increased bacterial oxygen consumption. From the results of EK bioremediation for pentadecane-contaminated soil, the bacterial population and removal efficiency at 1.88 $mA/cm^2$ were lower than those at 0.63 $mA/cm^2$. This is because the high oxygen production rate largely increased the production rate of organic acids, which reduced the electrolyte pH and bacterial activity. At 0.63 $mA/cm^2$, the highest bacterial population and removal efficiency could be obtained due to the appropriate oxygen production and small decrease in pH.

• Korean Chemical Engineering Research
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• v.49 no.6
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• pp.835-839
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• 2011

The characteristics of torch-type atmospheric pressure plasma and its sterilization effects have been analyzed. The length of plasma flame was varied with the level of applied voltage and the mixture gases composed of argon and oxygen. The effect of plasma flame on the temperature increase of surface treated was limited to $43^{\circ}C$ as a maximum temperature under exposing time of 10 min. The sterilization for E. coli was strongly affected by the applied voltage, the oxygen ratio in the mixture gas and the treatment time. At a high concentration of ozone, the increase of treatment time under the direct contact with plasma flame yields to maximize the effect of the sterilization on E. coli.