• Journal of the Korean Geotechnical Society
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• v.32 no.5
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• pp.49-55
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• 2016

This study aims to present the practical Nitrogen monoxide (NO) removal capacity of cement mortar with Titanium dioxide ($TiO_2$) which is one of the paving materials by considering the environment of pavement in urban areas. NO removal capacity test under designated conditions of humidity of inflow gas and the test with variation of the degree of saturation of specimen were conducted. In the test for humidity, dry specimen is subject to the test and NO removal ratio was observed. Humidity-NO removal ratio curve is a log normal distribution in shape, and the maximum NO removal ratio appears at specific humidity. NO removal capacity test relying on the degree of saturation was carried out with wet specimen to reflect the unsaturated pavement by rainfall and domestic sewage. Wet specimen presents less NO removal capacity than dry specimen and the recovering evolution of NO removal capacity follows evaporation. Moreover, $TiO_2$ under the specific depth of specimen hardly contributes to NO removal capacity.

• Journal of Animal Environmental Science
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• v.9 no.1
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• pp.1-8
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• 2003

This study was conducted to calculate the amount of $N_2O$ emission from livestock manure management in Korea. $N_2O$ is considered a greenhouse gas emitted from livestock manure treatment. In order to calculate $N_2O$ emission, a percentage of nitrogen from livestock manure, livestock manure treatment facilities, and the number of livestock were collected. The amount of annual N excretion from beef cattle, dairy cattle, pigs, laying hen, and broiler were 37.00, 20.42, 12.37, 0.56, and 0.29kg, respectively Calculated $N_2O$ emission in 1990, 2005, 2010, 2015, and 2020 were 3.71, 5.84, 6.07, 6.23, and 6.53Gg, respectively. Increased $N_2O$ percentage in 2005, 2010, 2015, and 2020 compared to 1990 were 57.4, 63.6, 67.9, and 76.0%, respectively.

• International Journal of Oral Biology
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• v.43 no.4
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• pp.209-216
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• 2018

Reactive oxygen species (ROS) and nitrogen species (RNS) are involved in cellular signaling processes as a cause of oxidative stress. According to recent studies, ROS and RNS are important signaling molecules involved in pain transmission through spinal mechanisms. In this study, a patch clamp recording was used in spinal slices of rats to investigate the action mechanisms of $O_2{^{{\bullet}_-}}$ and NO on the excitability of substantia gelatinosa (SG) neuron. The application of xanthine and xanthine oxidase (X/XO) compound, a ROS donor, induced inward currents and increased the frequency of spontaneous excitatory postsynaptic currents (sEPSC) in slice preparation. The application of S-nitroso-N-acetyl-DL-penicillamine (SNAP), a RNS donor, also induced inward currents and increased the frequency of sEPSC. In a single cell preparation, X/XO and SNAP had no effect on the inward currents, revealing the involvement of presynaptic action. X/XO and SNAP induced a membrane depolarization in current clamp conditions which was significantly decreased by the addition of thapsigargin to an external calcium free solution for blocking synaptic transmission. Furthermore, X/XO and SNAP increased the frequency of action potentials evoked by depolarizing current pulses, suggesting the involvement of postsynaptic action. According to these results, it was estblished that elevated ROS and RNS in the spinal cord can sensitize the dorsal horn neurons via pre- and postsynaptic mechanisms. Therefore, ROS and RNS play similar roles in the regulation of the membrane excitability of SG neurons.

• Korean Journal of Agricultural Science
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• v.48 no.3
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• pp.589-596
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• 2021

Nitrogen applied to soil is highly prone to leaching and volatilization leading to gaseous emissions of nitrous oxide (N₂O) and ammonia (NH₃) which are of great environmental concern. Usage of biochar to reduce the discharge of nitrogen to the environment has attracted much interest in the recent past. Biochar is produced by pyrolyzing various biomasses under oxygen-limited conditions. Biochar is a carbonized material with high adsorptive powers for not only plant nutrients but also heavy metals. The objective of this study was to investigate the adsorption characteristics of NH₄-N onto biochar made from pine needles. The biochar was produced at various pyrolysis temperatures including 300, 400 and 500℃ and holding times of 30 and 120 minutes. The Langmuir isotherm was used to evaluate the adsorption test results. The chemical properties of the biochar varied with the pyrolysis conditions. In particular, the pH, EC and total carbon content increased with the increasing pyrolysis conditions. The rate of adsorption of NH₄-N by the biochar decreased with the increasing pyrolysis conditions. Of these conditions, biochar that was pyrolyzed at 300℃ for 30 minutes showed the highest adsorption rate of approximately 0.071 mg·g^-1. Thus, the use of biochar pyrolyzed at low temperatures with a short holding time can most efficiently reduce ammonia emissions from agricultural land.

• Korean Journal of Environmental Agriculture
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• v.42 no.4
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• pp.457-464
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• 2023

The rendering residue generated by rendering disposal, an eco-friendly livestock carcass disposal method, is a useful agricultural resource. Methods for recycling this are being actively researched, and this study investigated the impact of applying rendered residue directly to soil on crop productivity and the agricultural environment. The chemical properties of the rendering residue were examined. The pH, OM, T-N, T-P, CaO, K₂O, and MgO content values were 5.47%, 59.8%, 9.22%, 2.96%, 2.16%, 0.51% and 0.10%, respectively. Treatment conditions were divided into control, inorganic fertilizer, and rendering residue, and rendering residue corresponding to 50, 100, and 200% nitrogen content was applied based on the amount of inorganic fertilizer nitrogen input. Greenhouse gases and ammonia were collected during the cultivation period. Rendering residue increased both the yield and growth of peppers and was effective in improving nutrients such as pH and OM of the soil after harvest. However, compared to inorganic fertilizer treatment, it increased emissions of nitrous oxide and methane as well as ammonia. It is judged that the direct agricultural use of rendering residue is difficult, and a utilization method is needed.

• Journal of Environmental Health Sciences
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• v.33 no.2 s.95
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• pp.92-97
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• 2007

A series of source tests were conducted to characterize emissions of nitrogen oxide(NOx, NO, $NO_2$), carbon mon oxide(CO), carbon dioxide$(CO_2)$ and total VOCs from portable combustion devices in steady-state using well-mixed chamber. Since use of portable gas range is widespread in houses and restaurants in Korea, it is important to characterize the emission of air pollutants and suggest optimum ventilation rate. Ranges of emission rates of air pollutants from portable gas ranges were $NO \;0.551\sim0.939mg/hr,\;NO_2\;0.354\sim1.080mg/hr,\;NO_x\;1.207\sim1.631mg/hr,\;CO\;1.389\sim4.21mg/hr,\;CO_2\;2426.823\sim2973.495mg/hr$, and VOCs $0\sim0.119mg/h$. Mean of personal exposure and indoor environment level of $NO_2$ by combustion of portable gas range were 74.7 ppb and 65.4 ppb, respectively, suggesting persons using portable gas range in houses and restaurants might be highly exposed. Required ventilation rate to control the air pollutants emitted from portable gas range was maximumly $3.131m^3/hr$ on the basis of $NO_2$ indoor air quality standard.

• Korean Journal of Environmental Agriculture
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• v.38 no.4
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• pp.237-244
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• 2019

BACKGROUND: Impact of incorporating hairy vetch into soil on mitigating nitrous oxide (N₂O) emissions from maize field in South Korea has not been investigated, whereas impacts on soil properties and nutrients for crops have been investigated. Therefore, this study was conducted to examine N₂O emission from upland soil incorporated with hairy vetch for one year in maize field. METHODS AND RESULTS: Hairy vetch was grown in an upland soil from November, 2017 to May, 2018 and incorporated into soil on May 25 of 2018. Control and conventional treatment (NPK) were included for comparison. Gas samples were collected weekly for a year to examine N₂O emissions from the soil. Chemical nitrogen (N) fertilizer stimulated N₂O emission in short term resulting in the greatest cumulative N₂O emission in NPK (6.72 kg N₂O ha^-1) compared to the control (4.04 kg N₂O ha^-1) and hairy vetch-incorporated field (5.43 kg N₂O ha^-1), and the greatest yield of maize from NPK, because total N input was much greater by NPK (186 N kg ha^-1) than by hairy vetch (81.6 N kg ha^-1). CONCLUSION: Incorporation of hairy vetch reduced N₂O emissions from the maize compared to the NPK-treated field. However, further research on improving crop productivity with incorporation of hairy vetch is needed.

• The Journal of Korean Medicine
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• v.30 no.2
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• pp.88-103
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• 2009

Objectives: There is currently increased interest in the identification of natural antioxidant compounds derived from various plants. Peony Root (PR) is used worldwide for the treatment of many types of cardiovascular disease including atherosclerosis and hypertension. It has been used in Korean traditional medicine for the treatment of glycosuria, hypertension and cancer. However, to date, no studies concerning the antioxidant properties of PR have been conducted. Therefore, this study was conducted to evaluate the in vitro scavenging activity, inhibitory effect of LDL oxidation of pro-oxidant reactive species and anti-thrombosis effect in response to treatment with PR using various screening methods including biological and non-biological oxidants. Methods: In this study, the antioxidant activity of extract from PR was studied with in vitro methods by measuring the antioxidant activity by TEAC, measuring the scavenging effects on reactive oxygen species (ROS) [superoxide anion, hydroxyl radical] and on reactive nitrogen species (RNS) [nitric oxide and peroxynitrite] as well as measuring the inhibitory effect on $Cu^{2+}$-induced human LDL oxidation and the inhibitory effect on collagen-induced platelet aggregation. Results: The PR extracts were found to have a potent scavenging activity of oxidative stress [DPPH, superoxide anion, hydroxyl radical, nitric oxide and peroxynitrite, etc.] as well as an inhibitory effect on LDL oxidation and on platelet aggregation. Conclusions: The PR extracts have anti-oxidative and anti-atherosclerotic effects in vitro system, which can be used for developing pharmaceutical drugs against oxidative stress and atherosclerosis.

• Fire Science and Engineering
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• v.14 no.2
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• pp.7-13
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• 2000

We had investigated thermal stability, Ignition temperature and fire gas for polyurethane foams used for manikin, cushion and interior finishing material. Decomposition of polyurethane foams with temperature was investigated using a DSC and the weight loss with temperature increase using a TGA in order to find the thermal hazard of polyurethane foams, and the ignition temperature of polyurethane foams according to species. We studied constant temperature among ignition temperature measuring methods. In addition, noxious gases for polyurethane foams according to combustion condition were analyzed using gas analyzer and GASTEC. As results, initial decomposition temperature of polyurethane foam used for interior finishing material was lower than those for manikin and cushion, and exothermic energy was higher. Ignition temperature of polyurethane foam of interior finishing material was $420^{\circ}$. All of combustion forms at $427^{\circ}$ and under were smoldering combustion, and it was combustion at $500^{\circ}$. As furnace temperature was increased, concentration of noxious gases such as carbon oxide, carbon dioxide, and hydrogen cyanide was increased. And nitrogen oxide at combustion condition($500^{\circ}$) was over 10 ppm.

• Journal of the Korean Vacuum Society
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• v.6 no.S1
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• pp.96-109
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• 1997

In order to simulate the corrosion behavior of Zr-4 alloy in pressurized water reactors it was implanted (or bombarded) with 190ke V $Zr^+\; and \;Ar^+$ ions at liquid nitrogen temperature and room temperature respectively up to a dose of $5times10^{15} \sim 8\times10^{16} \textrm{ions/cm}^2$ The oxidation behavior and electrochemical vehavior were studied on implanted and unimplanted samples. The oxidation kinetics of the experimental samples were measured in pure oxygen at 923K and 133.3Pa. The corrosion parameters were measured by anodic polarization methods using a princeton Applied Research Model 350 corrosion measurement system. Auger Electron Spectroscopy (AES) and X-ray Photoelectric Spectroscopy (XPS) were employed to investigate the distribution and the ion valence of oxygen and zirconium ions inside the oxide films before and after implantation. it was found tat: 1) the $Zr^+$ ion implantation (or bombardment) enhanced the oxidation of Zircaloy-4 and resulted in that the oxidation weight gain of the samples at a dose of $8times10^{16}\textrm{ions/cm}^2$ was 4 times greater than that of the unimplantation ones;2) the valence of zirconium ion in the oxide films was classified as $Zr^0,Zr^+,Zr^{2+},Zr^{3+}\; and \;Zr^{4+}$ and the higher vlence of zirconium ion increased after the bombardment ; 3) the anodic passivation current density is about 2 ~ 3 times that of the unimplanted samples; 4) the implantation damage function of the effect of ion implantation on corrosion resistance of Zr-4 alloy was established.