• Journal of The Korean Society of Agricultural Engineers
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• v.59 no.4
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• pp.1-15
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• 2017

Eutrophication of surface waters is of concern worldwide, because it can result in many undesirable water-quality and ecological problems, such as hypoxic 'dead' zones and harmful algal blooms, both associated with considerable economic costs. In this study, we used LSM (Land Surface Model) to simulate nitrogen in five major rivers in the Southern Korean Peninsula. The main objective of this research was to enhance nitrogen data for input of LM3V model in South Korea. Input data for nitrogen fluxes were categorized into three sections including agriculture fertilizer, livestock manure, atmosphere deposition, biological fixation, and sewage pollutants were used as the nitrogen input. For using LM3V model, the nitrogen input data were regenerated by considering states of agriculture and industry in South Korea at a $1/8^{\circ}$ resolution. Then, we simulated stream/river flows and N loads throughout the entire drainage networks in South Korea at a $1/8^{\circ}$ resolution. By using the same parameters for the entire country ($100,210km^2$), composed of 5 river basins with varying climate and land use, the model simulates spatial (11 sites) and temporal (1999~2010) patterns of flows and nitrate-N loads are resonable by comparing observed flow and nitrate-N loads. The r (Pearson's linear correlation) for water temperature, flow and nitrate-N at river were 080~0.93, 0.62~0.92 and 0.5~0.9 respectively. Based on enhanced N input data and model results, we find that LM3V model as land surface model can be applied in South Korea with interaction of atmosphere and land conditions.

• Journal of the Korean Magnetics Society
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• v.3 no.2
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• pp.87-93
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• 1993

Iron nitride (Fe-N) magnetic thin films were deposited using a DC magnetron sputtering system. Microstructures and magnetic properties were examined as a function of deposition power and nitrogen gas input ratio. The nitrogen content in the film was found to be the major factor determining the microstructure and the magnetic properties. The films deposited at low nitrogen input ratios have an $\alpha$-Fe structure of which the lattice is expanded due to the nitrogen atoms incorporated at the interstitial sites. As the nitrogen content in the film increases, the degree of lat-tice expansion increases and the value of saturation magnetization decreases linearly. The films with a high degree of lattice expansion give very low values of coercivity, which is attributed to the disturbance of colunmar growth and the decrease of surface roughness. Further increase in the nitrogen input ratio causes the phase transfonnation from $\alpha$-Fe to $Fe_{2-3}N$, resulting in the marked reduction in the saturation magnetization. The phase transformation occurs when, regardless of deposition conditions, the nitrogen content reaches at 15 at.% and the lattice is expanded by 5%.

• Journal of Soil and Groundwater Environment
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• v.22 no.4
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• pp.49-59
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• 2017

This study estimated the nitrogen budget, including gaseous nitrogen oxides ($NO_x$), of South Korea in 2012~2014. The nitrogen budget was classified into three categories: agricultural and livestock, forest, and city. To estimate the nitrogen budget, several input and output parameters were investigated, including deposition, fixation, irrigation, chemical fertilizer use, compost, fuel, denitrification, volatilization, runoff, crop uptake, leaching, and $NO_x$ emissions. The annual nitrogen inputs from 2012 to 2014 were 6,202,828, 6,137,708, and 6,022,379 ton/yr, respectively. The corresponding annual nitrogen outputs were 1,393,763, 1,380,406, and 1,360,819 ton/yr, respectively, signifying a slight decrease from 2012 to 2014. $NO_x$ was the parameter contributing to the nitrogen budget to the greatest extent. The annual ratios of $NO_x$ emissions by vehicles, power plants, and businesses were 0.31, 0.31, and 0.30 in 2012, 2013, and 2014, respectively. A change in government policy that prohibited the disposal of livestock manure and sewage sludge in the ocean from 2012 affected nitrogen budget profile. As a result, the ocean disposal ratio completely diminished, which differs from previous studies.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.6
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• pp.551-557
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• 2002

Carbon nitride films have been deposited on Si(100) substrate by a high voltage discharge plasma combined with laser ablation in a nitrogen atmosphere. The films were grown both with the without the presence of an assisting focused Nd:YAG laser ablation. The laser ablation of the graphite target leads to vapor plume plasma expending into th ambient nitrogen arc discharge area. X-ray photoelectron spectroscopy and Auger electron spectroscopy were used to identify the binding structure and the content of the nitrogen species in the deposited films. The nitrogen content of the films was found to increase drastically with an increase of nitrogen pressure. The surface morphology of the films was studied using a scanning electron microscopy. Data of infrared spectroscopy and x-ray photoelectron spectroscopy indicate the existence of carbon-nitrogen bonds in the films. The x-ray diffraction measurements have also been taken to characterize the crystal properties of the obtained films.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.1
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• pp.75-78
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• 2002

Si thin films on p-type (100) Si substrate have been prepared by a pulsed laser deposition technique using a Nd:YAG laser. The pressure of the environmental gas during deposition was 1 Torr. After deposition, Si thin film has been annealed again at 400-840$^{\circ}C$ in nitrogen ambient. Strong blue photoluminescence (PL) have been observed at room temperature. We report the PL properties of Si thin films with the variation of the annealing temperature.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.173-176
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• 2004

Silicon thin films on p-type(100) silicon substrate have been prepared by a pulsed laser deposition(PLD) technique using a Nd:YAG laser. The pressure of the environmental gas during deposition was 1 Torr. After deposition, silicon thin film has been annealed in nitrogen ambient. Strong blue photoluminescence(PL) has been observed at room temperature. We report the optical properties of silicon thin films with the variation of the deposition parameters.

• Animal Bioscience
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• v.35 no.2
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• pp.260-271
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• 2022

Objective: We aimed to investigate the effect of the differing amino acid (AA) release dynamics of two protein sources on the growth performance, nitrogen deposition, plasma biochemical parameters, and muscle synthesis and degradation of piglets when included in their diets at normal and low concentrations. Methods: Forty-eight piglets (Duroc×Landrace×Large White) with initial body weight of 7.45±0.58 kg were assigned to six groups and fed one of 6 diets. The 6 dietary treatments were arranged by 3×2 factorial with 3 protein sources and 2 dietary protein levels. They are NCAS (a normal protein content with casein), NBlend (a normal protein content with blend of casein and corn gluten meal), NCGM (a normal protein content with corn gluten meal), LCAS (a low protein content with casein), LBlend (a low protein content with blend of casein and corn gluten meal), LCGM (a low protein content with corn gluten meal). The release dynamics of AA in these diets were determined by in vitro digestion. The digestibility, utilization and biological value of nitrogen in piglets were determined by micro Kjeldahl method. Plasma insulin was measured by enzyme-linked immunosorbent assay kits. The protein expression of mediators of muscle synthesis and degradation was determined by western blotting. Results: Although the consumption of a low-protein diet supplemented with crystalline AA was associated with greater nitrogen digestion and utilization (p<0.05), the final body weight, growth performance, nitrogen deposition, and phosphorylation of ribosomal protein S6 kinase 1 and eIF4E binding protein 1 in the muscle of pigs in the low-protein diet-fed groups were lower than those of the normal-protein diet-fed groups (p<0.05) because of the absence of non-essential AA. Because of the more balanced release of AA, the casein (CAS) and Blend-fed groups showed superior growth performance, final body weight and nitrogen deposition, and lower expression of muscle ring finger 1 and muscle atrophy F-box than the CGM-fed groups (p<0.05). Conclusion: We conclude that the balanced release of AA from CAS containing diets and mixed diets could reduce muscle degradation, favor nitrogen retention, % intake and improve growth performance in pigs consuming either a normal- or low-protein diet.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.1
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• pp.60-65
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• 2016

The main objective of this research was to estimate the total mass of nitrogen discharged from various sources in paddy field area of South Korea in 2010 and 2013. Input and output budgets for nitrogen were estimated by mass balance approach. The mass balance approach reduces the effect of flow variations, and the large scale approach minimizes local effects, resulting in easier and faster establishment of strategy for nonpoint pollution problems. Nitrogen inputs were chemical fertilizer, compost, atmospheric deposition, biological fixation, and agricultural water, while crop uptake, denitrification, volatilization, and infiltration were nitrogen outputs. The estimated total nitrogen inputs for paddy field in South Korea were $266,211ton\;yr^{-1}$, $260,729ton\;yr^{-1}$, while those of total nitrogen outputs were $168,463ton\;yr^{-1}$, $164,994ton\;yr^{-1}$ in 2010 and 2013, respectively. Annual amounts of potential nitrogen outflow from paddy field were $97,748ton\;yr^{-1}$, $95,735ton\;yr^{-1}$ in 2010 and 2013. Also, annual rate of potential nitrogen outflow were 36.7%, 36.7% in 2010 and 2013, respectively.

• Journal of Environmental Science International
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• v.17 no.10
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• pp.1069-1073
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• 2008

Indoor air quality can be affected by indoor sources, ventilation, decay and outdoor levels. Although technologies exist to measure these factors, direct measurements are often difficult. The purpose of this study was to develop an alternative method to characterize indoor environmental factors by multiple indoor and outdoor measurements. Using a mass balance model and regression analysis, penetration factor (ventilation rate divided by the sum of ventilation rate and deposition constant) and source strength factor (source strength divided by the sum of ventilation rate and deposition constant) were calculated using multiple indoor and outdoor measurements. Subsequently, the ventilation rate and $NO_2$ generation rate were estimated. Mean of ventilation rate was 1.41 ACH in houses, assuming a residential N02 deposition constant of 0.94 $hr^{-1}$. Mean generation rate of $NO_2$ was 16.5 ppbv/hr. According to house characterization, inside smoking and family number were higher $NO_2$ generation rates, and apartment was higher than single-family house. In conclusion, indoor environmental factors were effectively characterized by this method using multiple indoor and outdoor measurements.

• Journal of Information Display
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• v.11 no.3
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• pp.109-112
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• 2010

The solid phase compositions and dielectric properties of silicon nitride ($SiN_x$) films prepared using the plasma enhanced chemical vapor deposition (PECVD) technique at a low temperature ($200^{\circ}C$) were studied. Controlling the source gas mixing ratio, R = $[N_2]/[SiH_4]$, and the plasma power successfully produced both silicon-rich and nitrogen-rich compositions in the final films. The composition parameter, X, varied from 0.83 to 1.62. Depending on the film composition, the dielectric properties of the $SiN_x$ films also varied substantially. Silicon-rich silicon nitride (SRSN) films were obtained at a low plasma power and a low R. The photoluminescence (PL) spectra of these films revealed the existence of nano-sized silicon particles even in the absence of a post-annealing process. Nitrogen-rich silicon nitride (NRSN) films were obtained at a high plasma power and a high R. These films showed a fairly high dielectric constant ($\kappa$ = 7.1) and a suppressed hysteresis window in their capacitance-voltage (C-V) characteristics.