• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2000.11a
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• pp.209-213
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• 2000

In this paper, the removal rate of NO in a reactor is measured first using nonthermal plasma generated from a wire-cylinder type reactor, then the spatial density distribution of NO particles is investigated using ICCD(Intensified Charged Coupled Device) camera. This research uses nonthermal plasma from electrical discharge to analyze the NO characteristics, and the measurements of NO discharge image and Distribution are performed using the ICCD camera to examine the NO characteristics more closely. Furthermore, the method of Laser Induced Fluorescence (LIF) is used to analyze the particular behavior of NO particles more specifically, to suggest a method of reducing exhaust gas, a serious environmental problem.

• International Journal of Oral Biology
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• v.40 no.4
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• pp.217-221
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• 2015

Cariogenic Streptococcus mutans encounters a variety of host defense factors produced in oral cavity. Nitric oxide (NO) and NO-mediated reactive nitrogen species are potential antimicrobials of innate immunity that can threaten the fitness of S. mutans in their ecological niches. Streptococcal strategies to detoxify cytotoxic NO, which allow S. mutans to persist in caries or other environments of the oral cavity, remain unknown. In this study, we directly measured NO consumption rates of S. mutans isolated in Korea. Surprisingly, all S. mutans strains were unable to consume exogenous NO efficiently, while an intracellular parasite Salmonella enterica serovar Typhimurium expressing the NO-metabolizing enzyme flavohemoglobin consumed most of the NO. This result suggested that S. mutans has alternative detoxification systems for tolerating NO-induced nitrosative stresses.

• Journal of Korean Society for Atmospheric Environment
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• v.10 no.2
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• pp.130-136
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• 1994

Concentration of volatile particulate nitrate(NH$_4$NO$_3$) in TSP in ambient air was determined from Feb. to Oct 1993. Sampling was carried out using a two-stage Andersen air sampler at the top of a five-story building located at Kon- Kuk University in Seoul Concentration of NH$_4$NO$_3$ in TSP was measured by Pyrolysis of sample filters at 16$0^{\circ}C$ for 1hr. Concentration of NH$_4$NO$_3$ was higher in winter time compared with that in summer time. Also, concentration of NH$_4$NO$_3$ was higher in fine particles compared with that in coarse particle. The range of NH$_4$NO$_3$concentration was between 2.99 and 9.86 $\mu\textrm{g}$/㎥. Weight fraction of NH$_4$NO$_3$ in total particulate nitrate was 31.1~59.5%, and weight fraction of NH$_4$NO$_3$ in YSP was 2.1~11.2%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.1
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• pp.109-116
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• 1992

Kimchi is a very popular traditional fermented vegetable in Korea, however, contaminations of $NO_3$, $NO_2$ and nitrosamines in Kimchi were suspected. In this review, ingredients used in manufacturing Kimchi, kinds of Kimchi, microorganisms involved the fermentation and nutritional values of Kimchi are introduced. The quantitated levels of $NO_3$, $NO_2$ and secondary amines in the ingredients of Kimchi, and the changes of the contents of $NO_3$, $NO_2$ and nitrosamines during Kimchi fermentation were shown. The level of $NO_3$ during Kimchi fermentation reduced greatly, and the content of $NO_2$ was also trace amounts. NDMA is a major nitrosamine found in Kimchi, but the levels were trace or not detected.

• Bulletin of the Korean Chemical Society
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• v.16 no.2
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• pp.157-163
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• 1995

The adsorption and decomposition of NO on a stepped Pt(111) surface have been studied using thermal desorption spectroscopy and Auger electron spectroscopy. NO adsorbs molecularly in two different states of the terrace and the step, which are distinguishable in thermal desorption spectra. NO dissociates via a bent species at the step sites on the basis of vibrational spectrum data reported previously. The dissociation of NO is an activation process : the activation energy is estimated to be about 2 kcal/mol. Increase in the NO dissociation with adsorption temperature is explained by a process controlled by diffusion of the dissociated atomic nitrogen from the step to the terrace of the surface. In addition to NO and N2, the desorption peak of N2O is observed. We conclude that the formation of N2O is attributed to surface reaction of NO and N adsorbed on the surface.

• Journal of Life Science
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• v.16 no.2 s.75
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• pp.192-198
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• 2006

Epidemiological studies have demonstrated an association between exposure to diesel exhaust particles (DEP) and adverse cardiopulmonary effects. Despite the epidemiological proof, the pathogenesis of DEP-related pulmonary diseases remain poorly understood. So, comprehensive in vivo and in vitro researches are required to know the effects of DEP on diverse lung diseases. Alveolar macrophages (AM) and airway epithelial cells are known as important cellular targets in DEP-induced lung diseases. Other studies have shown that nitric oxide (NO) is involved in particle matter induced lung injury. The present study was undertaken to determine whether DEP has an synergistic effects on lipopolysaccharide (LPS)-induced NO formation and inducible nitric oxide synthase (iNOS) with nitrotyrosilated-protein formation in cultured primary alveolar macrophages. The formation of NO was determined through the Griess reaction in the cultured medium and iNOS with nitrotyrosilated-proteins are analyzed by immunohistochemical staining and Western analysis. The results indicate that DEP exposure does not induce NO formation by itself, however DEP showed significant synergistic effects on LPS-induced NO formation. So, our results suggest that DEP inhalation could aggravate inflammatory lung disease through NO formation.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.5
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• pp.481-488
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• 2013

Nitric oxide ($NO_x$) formation characteristics in non-premixed diffusion flames of methane fuels have been investigated experimentally and numerically by adding 10% ammonia to the fuel stream, according to the variation of the oxygen ratio in the oxidizer with oxygen/carbon dioxide and oxygen/nitrogen mixtures. In an experiment of coflow jet flames, in the case of an oxidizer with oxygen/carbon dioxide, the $NO_x$ emission increased slightly as the oxygen ratio increased. On the other hand, in case of an oxygen/nitrogen oxidizer, the $NO_x$ emission was the maximum at an oxygen ratio of 0.7, and it exhibited non-monotonic behavior according to the oxygen ratio. Consequently, the $NO_x$ emission in the condition of oxyfuel combustion was overestimated as compared to that in the condition of conventional air combustion. To elucidate the characteristics of $NO_x$ formation for various oxidizer compositions, 1D and 2D numerical simulations have been conducted by adopting one kinetic mechanism. The result of 2D simulation for an oxidizer with oxygen/nitrogen well predicted the trend of experimentally measured $NO_x$ emissions.

• Asian Journal of Atmospheric Environment
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• v.9 no.4
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• pp.237-246
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• 2015

We conducted intensive observations of ozone, CO, $NO_x$ (=NO and $NO_2$), $NO_y$ (total odd nitrogen species including particulate nitrate) and total nitrate (the sum of gaseous $HNO_3$ and particulate nitrate) at Cape Hedo, Okinawa, Japan, from 19 March to 3 April, 2009, to investigate ozone production during long-range transport from the Asian continent. Ozone production efficiency (OPE) was used to evaluate photochemical ozone production. OPE is defined as the number of molecules of ozone produced photochemically during the lifetime of a $NO_x$ molecule. OPE is calculated by the ratio of the concentration increase of ozone to that of $NO_z$ ($=NO_y-NO_x$). Average OPE during observation was estimated to be $12.6{\pm}0.5$, but concentrations of ozone increased nonlinearly with those of $NO_z$. This non-linearity suggests that OPE depends on air mass origin and $NO_z$ concentrations. There were very different values of OPE for the same air mass origin, so that only the air mass origin alone does not control OPE. OPE was low when $NO_z$ concentration was high. We examined the correlation between $NO_z$ and $CO/NO_y$ ratios, which we used instead of the ratio of non-methane hydrocarbons (NMHCs) to $NO_x$. The $CO/NO_y$ ratios decreased with increasing $NO_z$ concentrations. These results indicate that competition reactions of OH with NMHCs and $NO_2$ are the rate determining steps of photochemical ozone production during long-range transport from the Asian continent to Cape Hedo, for high concentrations of nitrogen oxides.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.12
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• pp.837-842
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• 2014

A computer program is developed for the prediction of NO generation by the addition of water moisture and water electrolysis gas in LNG-fired turbulent reacting flow. This study is the first part to deal with the moisture effect on NO generation. In this study, parametric investigation has been made in order to see the reduction of thermal NO as a function of amount of moisture content in a LNG-fired flame together with the swirl and radiation effect. First of all, calculation results show that the flame separation together with the NO concentration separation are observed by the typical flow separation due to strong swirl flow. With a fixed amount of air, the increased amount of water moisture from 0 to 10% by 2% interval shows the decrease of NO concentration and flame temperature at exit are from $973^{\circ}C$ and 139 ppm to $852^{\circ}C$ and 71 ppm. The radiation effects on the generation on NO appears more dominant than swirl strength over the range employed in this study. However, for the strong swirl flow employed in this study, the flow separation cause the relatively high NO concentration observed near exit after peak concentration in the front side of the combustor.

• Journal of Bio-Environment Control
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• v.10 no.4
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• pp.207-212
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• 2001

The environmental characteristics, absorption rate of NO$_2$, physiological response, and quality of lettuces were examined in a semi-closed plant production system consisted of human and plant modules. Leaf lettuces were transplanted to 10-cm diameter pots at 4-to 5-leaf stage, and grown in a gas-fumigated plant module. Air containing NO$_2$was circulated 10 min-ON/ 20 min-OFF between the human and plant modules by a diaphragm. At 0.13, 0.30, and 0.45 $\mu$mol.mol$^{-1}$ NO$_2$, NO$_2$ decrements in the chamber during the 10 min were 0.040, 0.109, and 0.149 $\mu$mol.mol$^{-1}$ , respectively. The NO$_2$absorption rate of the plants was estimated to be 0.078 $\mu$mol.mol$^{-1}$ .m$^{-2}$ .min$^{-1}$ at 0.45 $\mu$mol.mol$^{-1}$ NO$_2$ was less than that of the control plant at 4th and 5th days, whereas the respiration rate was the same. The lettuce grown at 0.45 $\mu$mol.mol$^{-1}$ NO$_2$ had similar leaf length, leaf area, dry and fresh weights, and quality to that grown without NO$_2$.