• Journal of the Korean Chemical Society
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• v.46 no.1
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• pp.14-18
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• 2002

It is shown that one-electron reduction of nitric oxide (NO) to nitroxyl anion $(NO^-)$ can be accelerated by vibrational energy. Potential energy surfaces of NO and $NO^-$ reveal that the vertical transition between them has favorable energetics for vibrationally excited molecule. Also, Franck-Condon factors between NO and $NO^-$ vibrational wave functions are calculated. It shows that the number of open channels increases with increased vibrational energy. These results mean that we can control the rate of reduction of NO to $NO^-$ by radiating an appropriate light.

• Journal of Sericultural and Entomological Science
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• v.7
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• pp.53-63
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• 1967

In order to identify the bacteria living on the cocoons in Korea, the isolated bacterias' morphological. cultural and physiological characters has been determined through the detailed study. The second aim of this experiment was to protect against the bacteria which damage silk protein during storage. 1. The twelve strains of the bacteria were isolated and identified in the cocoons produced in Korea. The results of the identification are as the following. No 1, No 8; Bacillus subtilis variation No 2, ; Bacillus stearothermophilus No 3, ; Bacillus circulans No 5, No 6; Bacillus thuringiensis No 7, No 11; Bacillus brevis No 12, No l0; Bacillus cereus variation

• Journal of Korean Society for Atmospheric Environment
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• v.32 no.4
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• pp.422-434
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• 2016

This study was conducted to understand roles of $NO_x(=NO+NO_2)$ on high $O_3$ episodes at an urban monitoring station in Seoul. Concentrations of NO, $NO_2$, $NO_y$ and $O_3$ were measured intensively at KIST monitoring station which located at urban center in Seoul metropolitan area during May 18~June 13, 2015. Sampling period was planed because high $O_3$ and PM occurred frequently during from late spring to early summer months in Seoul. The experimental site locates in NW from center of Seoul and is surrounded by residential area. Belt highway of the city runs from north to west side nearby experimental site. Vehicle exhaust emissions due to heavy traffic influenced $NO_x$ concentration at the site during northwesterly wind. Specific $NO_2$ concentration was measured by Blue Light photolytic converter, and it was compared to $NO_2$ concentration measured by molybedenum converter. $[NO_2]_{phtolysis}$ was usually lower than $[NO_2]_{molybedenum}$ during the experiment period; however their diurnal variations were very similar. The linear relationship between these $NO_2$ concentrations was found to be $[NO_2]_{phtolysis}$=0.64 $[NO_2]_{molybedenum}$ - 2.6, $r^2$=0.83 during May 16~8, 2015. The difference between $NO_2$ by molybdenum converter and by photolytic converter (${\Delta}NO_2=[NO_2]_{molybedenum}-[NO_2]_{phtolysis}$) accounted for residual $NO_y$ which can represent $NO_z$ (=$NO_y-NO_x$). $O_3$ concentration showed typical daily trend which has maximum at late afternoon and minimum during the night. $O_3$ increased at a rate of 7 ppb/hr since 8 am. and reached the maximum concentration (~80 ppb) at 3 pm.. The diurnal pattern of $O_3$ was inversely related with that of $NO_2$, suggesting that the formation of $O_3$ was the result of photochemical activity of $NO_2$.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.2
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• pp.60-66
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• 2014

A control oriented model of the Lean $NO_x$ trap (LNT) was developed to determine the timing of $NO_x$ regeneration. The LNT model consists of $NO_x$ storage and reduction model. Once $NO_x$ is stored ($NO_x$ storage model), at the right timing $NO_x$ should be released and then reduced ($NO_x$ reduction model) with reductants on the catalyst active sites, called regeneration. The $NO_x$ storage model simulates the degree of stored $NO_x$ in the LNT. It is structured by an instantaneous $NO_x$ storage efficiency and the $NO_x$ storage capacity model. The $NO_x$ storge capacity model was modeled to have a Gaussian distribution with a function of exhaust gas temperature. $NO_x$ release and reduction reactions for the $NO_x$ reduction model were modeled as Arrhenius equations. The parameter identification was optimally performed by the data of the bench flow reactor test results at space velocity 50,000/hr, 80,000/hr, and temperature of $250-500^{\circ}C$. The LNT model state, storage fraction indicates the degree of stored $NO_x$ in the LNT and thus, the timing of the regeneration can be determined based on it. For practical purpose, this model will be verified more completely by engine test data which simulate the NEDC transient mode.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.3
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• pp.179-187
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• 2008

A mathematical modeling of $NO_x$ reduction in $NH_3$-SCR process is conducted. The present deterministic model solves one-dimensional conservation equations of mass and species concentrations for channel flows and the catalytic reaction. NO and NO_2$ reactions by the vanadium catalyst in the presence of $NH_3$ are calculated with the rate expressions of Langmuir-Hinshelwood scheme. The modeling was validated with extensive empirical data regarding $NO_x$ reduction efficiency. Analysis of De-$NO_x$ sensitivity conducted with regard to oxygen and water yielded highly accurate prediction over a wide range of $NO_2/NO_x$ ratios from 0 to 1 in a temperature range of $200^{\circ}C{\sim}550^{\circ}C$. The $NO_x$ reduction largely depends on $NO_2/NO_x$ ratio at temperatures lower than $300^{\circ}C$. NO reduction efficiency is significantly augmented with increasing in $NH_3$/NO ratio at higher temperatures, whereas rather insensitive to the $NH_3$/NO ratio at lower temperatures.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.131-131
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• 2012

We present our recent temperature-programmed desorption (TPD) study on catalytic reductions of $NO_x$ such as NO, $NO_2$, and $N_2O$ over rutile $TiO_2$(110) surfaces. Our results indicate that $NO_2$/NO readily reacts to give NO/$N_2O$ desorption at the substrate temperature as low as 100 K/70 K. Interestingly, $N_2O$, however, does not dissociate into $N_2$ and $O_{BBO}$ over the oxygen vacancy on the $TiO_2$(110) surface. Successive reduction of NO and $NO_2$ into $N_2O$ and NO, respectively, leaves oxygen atoms on the $TiO_2$(110) surface in a form of $O_{ad}$, which can induce additional reductive channels of NO and $NO_2$ at higher temperatures up to 400 K. During the repeated TPD cycles of $NO_x$, our x-ray photoelectron spectroscopy (XPS) analysis indicates that no N atom accumulates on the $TiO_2$ surface.

• Journal of Life Science
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• v.21 no.4
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• pp.486-493
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• 2011

Nitric oxide (NO) donors are a potent inducer of heme oxygenase-1 (HO-1). However, it is unclear whether or not HO-1 expression induced by NO donors is a direct consequence of NO released by NO donors. Here, we investigated the effects of NO donors on the expression of HO-1 in primary rat articular chondrocytes. NO donors (SIN-1, SNAP, and SNP) significantly induced the accumulation of HO-1 protein accompanied by an increase in HO-1 mRNA. NO donor-induced HO-1 expression exerted cytoprotection against NO and/or superoxide-induced cell death. Guanylate cyclase signaling was not associated with Nrf2 and HO-1 expression in NO donor-treated chondrocytes. Interestingly, NO scavenger carboxy-PTIO and SOD mimetic TEMPOL markedly inhibited NO donor-induced HO-1 expression in chondrocytes. In addition, NO donor-induced HO-1 expression was completely abrogated by the peroxynitrite scavenger MnTBAP. Since peroxynitrite can be physiologcally formed in the cell through reaction of NO with superoxide, we analyzed whether or not peroxynitrite could directly induce HO-1 expression in chondrocytes. Peroxynitrite treatment in chondrocytes evoked doseand time-dependent Nrf2 and HO-1 expression. These results indicate that HO-1 expression induced by NO donors in rat articular chondrocytes is due to NO-mediated peroxynitrite rather than NO.

• Transactions of the Korean hydrogen and new energy society
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• v.28 no.2
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• pp.220-224
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• 2017

Nitrogen dioxide ($NO_2$) is an important urban pollutant in Korea. Expecially, diesel vehicles are responsible for the most traffic rated nitrogen oxide ($NO_X$) emission, including nitric oxide (NO) and nitrogen dioxide ($NO_2$). Though nitrogen oxide ($NO_X$) emission from vehicle was applied a strict enforcement of emission standard, the specific $NO_2$ fraction in $NO_X$ ($NO_2/NO_X$) from various types of diesel vehicles was not understood. In order to investigate the fraction of $NO_2/NO_X$, the vehicle emission study was carried out at the facility of Transport Pollution Research Center (TPRC), National Institute of Environmental Research (NIER), Korea. Three different types of diesel vehicles(VAN, SUV, passenger) were tested on the NIER driving mode. The result of $NO_2/NO_X$ ratio was over 0.1 for all test vehicles and the highest $NO_2$ emission was observed at the van vehicle. The observation was showed that the emission trend of $NO_2/NO_X$ for passenger and SUV vehicles were inversely proportional. Also, as the emission standard has been strengthen, the emission rate of $NO_2$ has been decrease.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 1999.10a
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• pp.152-153
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• 1999

NO$_2$는 가장 중요한 대기 오염 물질 중 하나 이다. 도시 대기 중 자동차 배출가스와 다른 연소 방출이 NO$_2$의 주원인 물질이다. 대부분 초기 NO$_{x}$은 NO로 방출되고 결국에 가서는 대기 중 오존과 반응하여 NO$_2$로 바뀐다. NO$_2$ 예측을 위해서 그리고 제어 방법을 개발하기 위해서는 NO$_{x}$ 제어 요소를 알아내는 것과 어떤 지점의 NO$_2$ 농도를 알아내는 것이 매우 중요하다.(중략)

• 한국연소학회:학술대회논문집
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• 2002.06a
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• pp.157-162
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• 2002

The characteristics of DeNOx conversion process by plasma/post-heating system with the simulated gas containing ethene is investigated experimentally. Without plasma treatment, $NO-NO_2$ conversion doesn't occur by $400^{\circ}C$ in a mixture of $N_2/O_2$ with a trace gas of ethene. But $NO-NO_2$ conversion occurs as temperature increases above $400^{\circ}C$. The NO can, however, be converted to $NO_2$ at lower temperatures by treating the gas mixture with non-thermal plasma. The $NO-NO_2$ conversion enhances further by passing the plasma treated gas through the post-heating furnace. Results show that 20%${\sim}50%$ more conversion of NO to $NO_2$ is observed when the temperatures of the post-heating furnace are maintained at $300^{\circ}C$ or $400^{\circ}C$. The additional $NO-NO_2$ conversion by post-heating is due to the reaction of ethene with the byproducts or radicals generated from the plasma reaction.