• Fire Science and Engineering
• /
• v.29 no.6
• /
• pp.13-19
• /
• 2015

This study was performed to test the combustive properties of Pinus rigida specimens treated with phosphorus (P) and nitrogen (N) additives. Each Pinus rigida specimen was painted three times with 15 wt% P-N additive solutions at room temperature. After drying the treated specimens, the combustion properties were examined using a cone calorimeter (ISO 5660-1). The time to ignition (TTI) for the treated specimens was 90 to 148 s except for the specimen treated with PP/$4NH_4^+$, and the time to flameout (TF) was 556 to 633 s, which was longer than that of virgin plate. While the The specimens treated with P-N additives showed 12.5 to 43.4% higher mean heat release rate ($HRR_{mean}$) and 11.8 to 43.1% higher total heat release (THR) than virgin plate. The effective heat of combustion (EHC) was by 2.9 to 17.5% lower than that of virgin plate. It can thus be concluded that the combustion-retardation properties were partially improved compared to those of virgin plate.

• Applied Biological Chemistry
• /
• v.29 no.1
• /
• pp.78-82
• /
• 1986

Panax ginseng seedlings were grown in vermiculite with nutrient solution different in nitrogen, phosphorus ana potassium level. Ginsenoside contents of root were investigated by high performance liquid chromatogram. Elimination or increase of one of N.P.K. increased or decreased total saponin content. Nitrogen was most effective (15.5% for-N to 8.9% for 3N) and potassium least. Similar trend was shown in each ginsenoside. According to coefficient of variation in one nutrient treatment or among all nutrient treatments ginsenoside Re was most insensitive to nutrient change and also other environmental factors and Rd most sensitive. Diol content (PD) was more variable than triol (PT) and variation of PT/PD was about half of them. Variation of ginsenoside content by nutrient change had no relation with the ginsenoside content. Similarity of ginsenoside pattern slightly decreased with the difference of saponin content by nutrient change. Root weight was significantly small only in tap water plot.

• Korean Journal of Materials Research
• /
• v.19 no.12
• /
• pp.637-643
• /
• 2009

In this study, we analyzed the effect of silicon oxynitride matrix on the optical properties of Au nanoparticles dispersed on composite film and explored the effectiveness of the silicon in fine tuning the refractive index of the composite film for applications in optical waveguide devices. The atomic fraction of nitrogen in $SiO_xN_y$ films was controlled by varying the relative flow ratio of nitrogen gas in reactive sputtering and was evaluated optically using an effective medium theory with Bruggeman geometry consisting of a random mixture between $SiO_2$ and $Si_3N_4$. The Au nanoparticles were embedded in the $SiO_xN_y$ matrix by employing the alternating deposition technique and clearly showed an absorption peak due to the excitation of surface plasmon. With increasing nitrogen atomic fraction in the matrix, the surface plasmon resonance wavelength shifted to a longer wavelength (a red-shift) with an enhanced resonance absorption. These characteristics were interpreted using the Maxwell-Garnett effective medium theory. The formation of a guided mode in a slab waveguide consisting of 3 $\mu$m thick Au:$SiO_xN_y$ nanocomposite film was confirmed at the telecommunication wavelength of 1550 nm by prism coupler method and compared with the case of using $SiO_2$ matrix. The use of $SiO_xN_y$ matrix provides an effective way of controlling the mode confinement while maintaining or even enhancing the surface plasmon resonance properties.

• Korean Journal of Organic Agriculture
• /
• v.13 no.3
• /
• pp.281-289
• /
• 2005

In order to find out an alternative way of analysis of food waste compost, the Near Infrared Reflectance Spectroscopy(NIRS) was used for the compost assessment because the technics has been known as non-detructive, cost-effective and rapid method. One hundred thirty six compost samples were collected from Incheon food waste compost factory at Namdong Indurial Complex. The samples were analyzed for nitrogen, organic matter (OM), ash, P, and K using Kjedahl, ignition method, and acid extraction with spectrophotometer, respectively. The samples were scanned using FOSS NIRSystem of Model 6500 scanning mono-chromator with wavelength from $400\~2,400nm$ at 2nm interval. Modified partial Least Squares(MPLS) was applied to develop the most reliable calibration model between NIR spectra and sample components such as nitrogen, ash, OM, P, and K. The regression was validated using validation set(n=30). Multiple correlation coefficient($R^2$) and standard error of prediction(SEP) for nitrogen, ash, organic matter, OM/N ratio, P and K were 0.87, 0.06, 0.72, 1.07, 0.68, 1.05, 0.89, 0.31, 0.77, 0.06, and 0.64, 0.07, respectively. The results of this experiment indicates that NIRS is reliable analytical method to assess some components of feed waste compost, also suggests that feasibility of NIRS can be Justified in case of various sample collection around the year.

• Membrane and Water Treatment
• /
• v.3 no.2
• /
• pp.133-140
• /
• 2012

The overall performance of BNR-MBR, so-called Anoxic-Anaerobic-Aerobic Membrane Bioreactor ($A^3$-MBR), developed for nutrient removal was studied to determine the efficiencies and mechanisms under different solid retention time (SRT). The reactor was fed by synthetic high-rise building wastewater with a COD:N:P ratio of 100:10:2.5. The results showed that TKN, TN and phosphorus removal by the system was higher than 95%, 93% and 80%, respectively. Nitrogen removal in the system was related to the simultaneous nitrification-denitrification (SND) reaction which removed all nitrogen forms in aerobic condition. SND reaction in the system occurred because of the large floc size formation. Phosphorus removal in the system related to the high phosphorus content in bacterial cells and the little effects of nitrate nitrogen on phosphorus release in the anaerobic condition. Therefore, high quality of treated effluent could be achieved with the $A^3$-MBR system for various water reuse purposes.

• Korean Journal of Soil Science and Fertilizer
• /
• v.10 no.1
• /
• pp.29-37
• /
• 1977

The mineralization of soil nitrogen, amino acid composition of acid hydrolizable organic nitrogen of four Korean soils were investigated in comparison with four Japanese (Hokuriku district) soils which is similar in nitrogen content but different in characteristics of clay minerals. The mineralization rate and pattern were quite different between Korean and Japanese soils; Korean soils were low in amount of mineralized nitrogen but porduced much ammonium nitrogen during the later stage of incubation. In Korean soils the ratio of acid hydrolizable nitrogen to total; especially ${\alpha}$-amino nitrogen and hydrolizable ammonium nitrogen were low while hexosamine content was considerablly high (greater than 10%) In all soils the amount of mineralized nitrogen showed significant positive correlation with ammonium nitrogen and ${\alpha}$-amino nitrogen in acid hydrolizate. The amino acid composition of acid hydrolizate of paddy soils showed higher in basic amino acids and lower in acidic amino acids than those of up land soils (humic volcanic ash soil) from both countries. Alanine content was low in Korean soils. Proline showed increasing trend with nitrogen content but aspartic acid decreasing.

• Applied Microscopy
• /
• v.44 no.2
• /
• pp.79-82
• /
• 2014

Aluminum nitride (AlN) powder was easily synthesized by the direct nitridation of Al melt containing ~20 wt.% Mg catalyst and the nitriding behavior was investigated by thermodynamic calculation and through observations of electron microscopy and X-ray diffraction. The addition of Mg catalyst decreased the nitriding temperature below $1,000^{\circ}C$, which is comparable to the high nitriding temperature of $1,400^{\circ}C$ required in carbothermal method. It was caused by a significant increase of the solubility of nitrogen gas due to the increase of Mg catalyst in Al melt. The dissolved nitrogen gas met Mg catalyst and was transformed into metastable $Mg_3N_2$. Finally the metastable phase reacted with Al to AlN.

• Journal of the Korean Magnetics Society
• /
• v.15 no.2
• /
• pp.130-132
• /
• 2005

Tungsten carbon nitride (W-C-N) thin films were produced by reactive radio frequency (RF) magnetron sputter-ing of tungsten in $Ar-N_2$ gas mixture. The effects of the variation of nitrogen partial pressure on the composition, and structural properties of these films as well as the influence of post-deposition annealing have been studied. When $La_{0.67}Sr_{0.33}MnO_3$ was coated on the W-C-N/Si substrate, coercivity ($H_c$) and magnetization at room temperature shows 58.73 Oe, and 29.4 emu/cc, respectively. In order to improve the diffusion barrier characteristics, we have studied the impurity behaviors to control the ratios of nitrogen and carbon concentrations.

• Asian-Australasian Journal of Animal Sciences
• /
• v.27 no.1
• /
• pp.24-29
• /
• 2014

The objective of this study was to assess the effect of substituting corn with soybean hulls on the ingestive behavior and nitrogen balance of Santa Ines lambs. A total of 25 lambs with an initial body weight of $20{\pm}2$ kg at approximately six months of age, sheltered individually in stalls ($1.10m{\times}1.0m$), considering an entirely casual experimental delineation. Soybean hulls were substituted for corn at 0, 250, 500, 750, and 1,000 g/kg of dry matter (DM). The time spent feeding, ruminating, masticating, and resting was not affected by the substitution of corn with soybean hulls. In fact, the feeding efficiency in g DM/h and the rumination efficiency in g DM/bolus increased linearly with soybean hull substitution in the feed. Although the nitrogen balance was not altered by the use of soybean hulls as a substitute for corn in the diets of Santa Ines lambs, the N ingested and N digested expressed in g/d, N retained as a percentage of that ingested, and N retained as a percentage of that digested displayed quadratic behavior. In conclusion, corn can be substituted with soybean hulls up to 1,000 g/kg of dry matter in the concentrate, without changing the ingestive behavior and nitrogen balance.

• Journal of Korean Society on Water Environment
• /
• v.23 no.2
• /
• pp.179-183
• /
• 2007

This study was carried out to evaluate water quality based on physicochemical properties, including ammonium nitrogen ($NH_3-N^+$), nitrate nitrogen ($NO_3-N^-$), consumption of $KMnO_4$ and microbial indicators, such as total colony counts and total surveyed a group of 30 samples three times in 2005 (January to March, July to September, October to December). The mean concentration values of ammonium nitrogen ($NH_3-N^+$), nitrate nitrogen ($NO_3-N^-$) and the consumption of $KMnO_4$, were 0.01 mg/L (range 0.00~0.09 mg/L), 0.48 mg/L (range 0.00~3.31 mg/L) and 0.61 mg/L (0.0~3.42 mg/L), respectively. Based on the results, total colony count was detected in the ranges of 0~412 CFU/mL. In details, 84.4% of test samples was ${\leq}30CFU/mL$, 10.0% was 30~100 CFU/mL and 5.6% was ${\geq}100CFU/mL$. The detected rate of total coliforms was 6.6%. In conclusion, the ground water quality of 30 military facilities in Seoul, Kyunggi-do, and Inchon-city was acceptable for drinking except for a few detection of total colony count and total coliforms over standard.