• Journal of The Korean Society of Agricultural Engineers
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• v.63 no.3
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• pp.35-45
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• 2021

Digestate or slurry produced from anaerobic digestion is mostly applied to crop lands for its disposal and recovering nutrients. However, minimizing nitrogen losses following field application of the digestate is important for maximizing the plant's nitrogen uptake and reducing environmental concerns. This study was conducted to assess the effects of three different biogas digestate application techniques (sawdust mixed with digestate (SSD), the hole application method (HA), and digestate injected in the soil (SD)) on nitrate leaching potential in the soil. A pot laboratory experiment was conducted at room temperature of 25 ± 2 ℃ for 107 days. The experimental results showed that sawdust application method turned out to be appropriate for quick immobilization of surplus N in the form of microbial biomass N, reflecting its lower total nitrogen and NH₄-N contents and low pH. The NH₄-N and total nitrogen fate in the soil fertilized with manure showed no statistically significant (p > 0.05) differences between the different methods applied during the incubation time under room temperature. In contrast, NO₃-N concentration indicates significant reduction in sawdust treatment (p < 0.05) compared to the control and other application methods. However, the soil sawdust mixed with digestate was more effective than the other methods, because of the cumulative labile carbon contents of the amendment, which implies soil net N immobilization.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.9-12
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• 1998

Film characteristics of thin reoxidized nitrided oxides were investigated by SIMS analysis and C-V method in order to use the gate dielectric for charge-trap type NVSMs instead of ONO stacked layers. Nitric oxide(NO) annealed film has the nitrogen content sharply peaked at the Si-SiO$_2$ interface, while it is broad for nitrous oxide($N_2$O) ambient. The nitrogen peak concentration increased with anneal temperature and time. The position of nitrogen content in the oxide layer was due to be precisely controlled. For the films annealed NO ambient at 80$0^{\circ}C$ for 30min. followed by reoxidized at 85$0^{\circ}C$, the maximum memory window of 3.5V was obtained and the program condition was +12V, 1msec for write and -l3V, 1msec for erase.

• Journal of Korean Society of Water and Wastewater
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• v.32 no.5
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• pp.371-379
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• 2018

The lack of seed sludges for Ammonium Oxidizing Bacteria (AOB) and slow-growing ANaerobic AMMonium OXidation (ANAMMOX) bacteria is one of the major problem for large-scale application. In this study, $24m^3$ of single-stage SBR (Sequencing Batch Reactor) was operated to remove nitrogen from reject water using AOB and ANAMMOX bacteria cultivated from activated sludge in the field. The ANAMMOX activity was found after 44 days of cultivation in the ANAMMOX cultivation reactor, and then $0.66kg\;N/m^3/d$ of the nitrogen removal rate was achieved at $0.78kg\;N/m^3/d$ of the nitrogen loading rate at 153 days of cultivation. The AOB cultivation reactor showed $0.2kg\;N/m^3/d$ of nitrite production rate at $0.4kg\;N/m^3/d$ of nitrogen loading rate after 36 days of operation. The cultivated ANAMMOX bacteria and AOB was mixed into the single-stage SBR. The feed distribution was applied to remove total nitrogen stably in the single-stage SBR. The nitrogen removal rate in the single-stage SBR was gradually enhanced with an increase of specific activities of both AOB and ANAMMOX bacteria by showing $0.49kg\;N/m^3/d$ of the nitrogen removal rate at $0.56kg\;N/m^3/d$ of the nitrogen loading rate at 54 days of operation.

• Applied Biological Chemistry
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• v.25 no.3
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• pp.142-149
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• 1982

Use efficiency of top-dressed labelled nitrogen(30% at ear formation stage) ranged 23 to 61%(five fields) with no clear difference between varieties. In high yield soil the use efficiency of top-dressed nitrogen was higher and more than 50% of fertilizer nitrogen in plant seemed to be taken up after ear formation, $^{15}N$ excess was greatest in grain indicating that top-dressed nitrogen translocates easily to grain. The difference of $^{15}N$ excess between grain and straw was greater in Tonsil line than in the local indicating faster nitrogen translocation in Tangil. Percent nitrogen derived from top-dressed nitrogen ranged 14 to 27% in aerial part. Two 3-hill plots per treatment could be enough for $^{15}N$ experiment under field condition if there is specific care.

• Korean Journal of Soil Science and Fertilizer
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• v.49 no.6
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• pp.751-759
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• 2016

It is known that the poor soil fertility of newly reclaimed saline soils is due to the lack of organic matter and available mineral nutrients for crop production. The effect of green manuring with Sesbania aculeata in combination with five rates of urea-N treatments (N0. N25, N50, N75, N100) on the productivity of a subsequent whole-crop barley and the fertility of the reclaimed saline soil in Saemangeum was evaluated in the field during 2013-2014 growing season. Sesbania was grown during summer season (June to October). The amount of Sesbania incorporated was $16.2Mg\;ha^{-1}$. Sesbania contributed to $393kg\;N\;ha^{-1}$ to the soils when ploughed down and incorporated before whole-crop barley cultivated. The performances of whole-crop barley following sesbania incorporation were significantly affected by a combination of Sesbania manuring and different N rates. The N fertilizer equivalence without N fertilizer following Sesbania was 42.6% ($63.9kg\;N\;ha^{-1}$), compared with N100 ($150kg\;N\;ha^{-1}$) in fallow soils. The whole-crop barley yield responded to N fertilizer rates in both sesbania-amended and fallow soil. The yield response to nitrogen rates in fallow soil was linear (Y=0.0586X+3.3011, $R^2=0.9534$), whereas that in sesbania-amended soils was quadratic (Y= -0.001X2+0.1322X+5.7143, $R^2=0.9576$). The yield of whole-crop barley in sesbania-amended with increasing N rates was increased up to SN75 (115 kgN) $10.3Mg\;ha^{-1}$. Apparent N recovery (ANR) of whole-crop barely showed decreased with sesbania plus increasing rates of N fertilizer. Despite higher yield with sesbania manuring plus increasing N rates, the contributions of N from Sesbania with increasing N rates to whole-crop barley were decreased, whereas those from fertilizer increment due to excessively mineralized Nitrogen. Considering yield, ANR, N contribution from Sesbania and nitrogen fertilizer, the optimum N rate was N50 rate following sesbania incorporation.

• Korean Journal of Soil Science and Fertilizer
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• v.25 no.4
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• pp.378-386
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• 1992

This experiment was conducted to investigate the effects of inoculation of the Bradyrhizobium sp.(Arachis) HCR-46 and fertilizer nitrogen application on nodulation, $N_2$-fixation of cowpea group legume(Seowon dongbu, Seonwha nogdu, Chungju pat, Youngho tangkong). Treatments consisted of five uninoc.+N : O, uninoc.+N : 6kg/10a. inoc.+N : O, inoc.+ N : 6kg/10a, inoc.+N : 12kg/10a. 1. Initial nodulation time of cowpea group legume by inoculation of Bradyrhizobium sp. HCR-46 was 12~21 days, and it was delayed as more fertilizer nitrogen was added. 2. The number and dry weight of nodule were increased as growth period elapsed, but decreased as fertilizer nitrogen was added. 3. Dry matter production and amount of nitrogen uptake were increased by inoculation and the effects of inoculation were increased when fertilizer nitrogen of 6kg/10a was applied. 4. Amount of fixed nitrogen by inoculation of fertilizer nitrogen not applied was higher than the case of 6kg/10a applied and that of peanut was higher than the other legumes(cowpea, mung bean and adzuki).

• KSBB Journal
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• v.25 no.6
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• pp.553-558
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• 2010

Increasing demands on fossil fuel have led to the unprecedented attraction to microalgal biofuel as an alternative energy. In this study, we investigated growth and lipid productions of microalga Nannochloris oculata under various carbon dioxide or nitrogen source concentrations and irradiance conditions. Biomass production of N. oculata was highest under 2% $CO_2$ with 0.3 flow rate (vvm). In addition, biomass productivities were proportional to the concentration of nitrogen source, whereas lipid biosynthesis was suppressed under higher nitrogen concentration (up to 50 mg/L). High irradiation ($160{\sim}180\;{\mu}mol/m^2{\cdot}s$) enhanced growth rate and lipid production of N. oculata.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.283-283
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• 2007

Titanium nitride thin films were deposited on $SiO_2$/Si substrate by rf-reactive magnetron sputtering. The structural and electrical properties of the films were investigated with various $N_2/(Ar+N_2)$ flow ratios (nitrogen/argon flow ratio). The resistivity as well as temperature coefficient of resistance (TCR) of the films strongly depends on phase structure. For the films deposited at nitrogen/argon flow ratio of below 5%, the resistivity increased with increasing nitrogen/argon flow ratios. However, the resistivity of the film deposited at nitrogen/argon flow ratio of 7% decreased drastically; it is even smaller than that of metal titanium nitride. A near-zero TCR value of approximately 9 ppm/K was observed for films deposited at nitrogen/argon flow ratio of 3%.

• Progress in Superconductivity and Cryogenics
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• v.21 no.3
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• pp.47-50
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• 2019

The paper gives the results of the experiments with a model two-section REBCO solenoid cooled by either gaseous helium (GHe) or sub-cooled/solid nitrogen (SN2) in (50-77) K temperature range. The major cooling source was a single-stage cryocooler Sumitomo CH-110 with the cooling power of 175 W and 130 W at 77 K and 50 K respectively. The coil itself was not directly conduction cooled. We compare the time taken by both coolants to obtain the temperature of the magnet of about 50 K and the homogeneity of the temperature distribution within the cryostat. Test results for the coil operation in solid nitrogen together with the comparison of its critical properties in SN2 and GHe are also presented.

• The Korean Journal of Ecology
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• v.14 no.3
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• pp.317-325
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• 1991

Mineral nitrogen dynamics and net mineralization of nitrogen in oak(quercus accutissima) and pine(pinus rigida) forest soils were studied. Nitrogen mineralization was determined over 8-week period by incubation method at laboratory. Initial water content of incubating soils was adjusted by applying suction(30mmhg), and lossof water during incubation was recovered with deionized water using syringe at every 3 or 4days. Temperature of incubator was maintained with 35+0.3c during the incubation period. Content of organic matter, total nitrogen, nh4-n and no3-n in soils in oak stand were significantly highter than those in pine stand. soil ph was lower in pine stand than in oak stand. initial nh4-n and no3-n of soils used in incubation experiment were 12.6 ug/g and 6.5 ug/g for oak stand, and 5.3ug/g and 5.1 ug/g for pine stand, respectively. Production of nh4-n increased from the beginning st both stands, and showed a peak at 5th week in oak stand(28.5 ug/g) and 6th week in pine stand(16.7 ug/g), and then decreased. intial no3-n of soils in oak(6.5 ug/g) and pine(5.1ug/g)stands, increased to 36.2 ug/g in soils of oak stand(5th week) and 13.4 ug/g in pine stand(4th week), respectively. The low values of no3-n of the field soil in the growing season compared with those of incubating soils at both stands indicate that considerable amount of nh4-n and no3-n produced in soils of oak and pine stands during two-months incubation were 59.7 and 141.6mg/kg soil, and 51.9 and 41.2mg/kg soil, respectively.