• 한국산업융합학회 논문집
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• 제24권6_2호
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• pp.909-917
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• 2021

This study was carried out experimentally on the production and properties of silicon nanopowders characteristics using a transferred type arc plasma apparatus. To investigate the properties of silicon nanopowder, the purity of argon gas(99.999%, 99.9%) and the partial pressure ratio of nitrogen gas(0~90%) were varied. The total pressure in chamber is 400Torr and the silicon chunk amount used as raw material is 300g. The power supplied to the cathode to generate arc plasma was 9~12kW/h, and the electrode was made of tungsten and graphite with a diameter of 13mm. The particle size, impurity elements and powder evaporation rate of the silicon powder were analyzed using the XRD, FE-SEM, TEM and electronic scale. According to the purity of argon gas, the silicon evaporation rate and the particle size were similar, and impurities were generated more in the case of 99.9% purity than 99.999%. When argon gas and nitrogen gas were mixed in the chamber, the silicon evaporation rate and particle size increased as the partial pressure ratio of nitrogen gas increased. In particular, when the partial pressure ratio of nitrogen gas was 80%, the silicon evaporation rate 80g/h, and the particle size was about 80~100nm.

• 한국작물학회지
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• 제33권3호
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• pp.209-214
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• 1988

질소비료의 증비와 숙도의 차이가 버어리종 잎담배의 수량과 품질 및 내용성분에 미치는 영향을 시험한 결과는 다음과 같다. 1. 질소비료가 증가될수록 건조엽의 적색도가 증가되었고, 2. 엽분별 수확시기를 보면 하위엽은 미숙엽에서, 상위엽은 과숙엽에서 수확할 때 kg당 가격이 가장 낮았다. 3. 미숙엽과 과숙엽은 수량이 대등하였으나 과숙엽은 수량이 떨어졌다. 4. 질소비료의 증비와 숙도에 따른 단백질 pattern의 차이는 나타나지 않았다. 5. 생육후기에는 비료수분 및 숙도에 따른 Nitrate reductase 활성도에는 차이가 나타나지 않았다.

• 한국작물학회지
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• 제53권spc호
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• pp.72-77
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• 2008

This study was carried out to determine the response of the rice yield and grain quality by rice leaf folder (RLF, Cnaphalocrocis medinalis G.) and identify the damages caused by different transplanting dates, nitrogen amounts and chlorophyll amounts (SPAD value) of rice leaf. As the damage degree of RLF was getting severer, the ripened grain rate and 1000-grain weight were decreased and due to the increasing of chalky rice rate the rate of head rice was reduced. Therefore, the yield of head rice was decreased by 36% in heavily damaged rice plant. Among the physicochemical characteristics, protein content of rice grain was increased but amylose content was reduced, consequently, the palatability was deteriorated in heavily damaged rice by RLF. The degree of damage of RLF was getting serious as transplanting date was delayed and as the amount of nitrogen was increased. In the relationship between the SPAD value and the damage degree of RLF, as the SPAD value was increased by nitrogen fertilizing, the damage degree was also increased exponential functionally.

• 한국환경과학회지
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• 제17권11호
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• pp.1265-1271
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• 2008

Aerated submerged bio-film (ASBF) pilot plant has been developed. The presented studies optimized an inexpensive method of enhanced wastewater treatment. The objectives of this research were to describe pilot scale experiments for efficient removal of dissolved organic and nitrogen compounds by using ASBF reactor in plug-flow reactor (PFR) and improve understanding of dissolved organic matter and nitrogen compounds removal rates with dynamic relationships between heterotrophs and autotrophs in the fixed-film reactor. This research explores the possibility of enhancing the performance of shallow wastewater treatment lagoons through the addition of specially designed structures. This direct gas-phase contact should increase the oxygen transfer rate into the bio-film, as well as increase the micro-climate mixing of water, nutrients, and waste products into and out of the bio-film. This research also investigated the efficiency of dissolved organic matter and ammonia nitrogen removals in the ASBF. As it was anticipated, nitrification activity was highest during periods when the flow rate was lower, but it seemed to decline during times when the flow rate was highest. And ammonia nitrogen removal rates were more sensitive than dissolved organic matter removal rates when flow rates exceeded 2.2 L/min.

• The Korean Journal of Ecology
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• 제18권4호
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• pp.493-502
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• 1995

Nodulation phenology in relation to plant phenology, vertical distribution of nodul and root biomass in different soil, correlation between nodule and root size, and nitrogen mineralization around the rhizosphere by ion-exchange resin bag buried at 10 cm of soil were studied in Elaeagnus nmbellata (autumn-olive) stand, Korea. Nodulation appeared from spring to autumn and nodule phenology was coincided with the timing of root activity rather than that of foliation. Nodul size increased in proportion to the root size. In the sand dune with the lower root biomass, nodule appeared up to 80 cm deep in soil and the nodule biomass was 1,070 kg/ha, which was the highest value reported for several actinorhizal plants in the temperate regions. It is suggested that nodule distribution and production are mainly influenced by soil aeration among environmental factors. The higher ammonification or lower nitrification rate contrasted markedly with the earlier studies that reported lower ammonification or higher nitrification in actinorhizal plant soil. Nitrogen mineralization rate around the rhizosphere with root and nodule was characterized by higher nitrification rate than that in the control soil without root and nodule.

• E2M - 전기 전자와 첨단 소재
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• 제8권2호
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• pp.196-203
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• 1995

We presented Tungsten and Tungsten Nitride thin films deposited by RF and DC sputtering. It deposited at various conditions that determining the resistivity and sheet resistivity by stabilizing the basic theory. We investigated properties of the resistivity and sheet resistivity of these films under various conditions, temperature of substrate, flow rate of the argon gas and content of nitrogen from nitrogen-argon mixtures. As the temperature of substrate increased and the flow rate of the argon gas decreased, the resistivities of these films reduced by structural transformation. We found that these resistivities were depend on the temperature of substrate, flow rate and electric power. Very highly resistive tungsten films obtained at 10W RF power. On the contrary, we found that films deposited by DC sputtering, from which very lowly resistive tungsten films were obtained. Tungsten nitride thin films deposited by reactive DC sputtering and the resistivities of these films increased as the content of nitrogen gas increased from nitrogen-argon mixture. And also we found the results show very good agreement, compared with experimental data.

• 한국작물학회지
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• 제35권6호
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• pp.497-503
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• 1990

질소와 가리 시용량이 버어리종 잎담배(1988년; Burley 21, 1989년 ; Burley 21과 KB 101)의 생육, 수량 및 품질에 미치는 영향을 알아보기 위하여 질소 3수준(1988년 ; 17.5, 22.75, 28.0kg/10a, 1989년 ; 12.5, 17.5, 22.5kg/10a), 가리 3수준(1988년 ; 17.5, 35.0, 52.5kg/10a, 1989년 ; 25.0, 35.0, 45.0kg/10a)을 두어 포장에서 시험한 바, 그 결과를 요약하면 다음과 같다. 1. 적심기 생육에 미치는 질소 시용량의 영향은 년차간 변이가 큰 것으로 나타났으며 가리시용량은 적심기 생육에 별다른 영향을 미치지 않았다. 2. 질소나 가리 시용량이 생육기간중의 엽중 질소함량에는 비교적 큰 영향을 미쳤으나 가리함량에 미치는 영향은 비교적 작았다. 3. Burley 21에 비하여 KB 101이 다수성이었으며, 질소감비상태에서의 생산성도 높았다. 4. 질소를 22.75kg/10a까지 시용할 때는 수량과 품질이 높아졌으나, 그 이상 시용할때는 수량은 증가되지 않고 품질은 낮아졌다. 5. 가리시용량이나 가리/질소 시용비에 따른 수량, 품질 차이는 크지 않았으나, 가리/질소 시용비가 작을 때는 품질이 다소 낮아졌다 6. 질소시용량이 22.75kg/10a을 초과할 때, 잎담배 수량 및 품질면에서 유리한 점은 없었으며, 가리시용량은 35.0kg/10a이면 충분하며 그 이하로의 감비도 여지가 있을 것으로 생각된다.

• 상하수도학회지
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• 제22권3호
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• pp.307-314
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• 2008

In this study, the effects of applied voltage, solution pH and coexistence of other ions such as sulfate ion (${SO_4}^{2-}$) and chloride ion ($Cl^-$) were investigated on the removal of nitrate-nitrogen ($NO_3{^-}-N$) from ground water by electrodialysis. The examined operating conditions were evaluated for optimizing the removal efficiency of $NO_3{^-}-N$. Real ground water samples taken from a rural area of Yongin city and artificial ones with components similar to the real ground water were tested for the study, which contained $NO_3{^-}-N$ concentration of 17mg/L that exceeds current drinking water quality standard of 10 mg/L. The increase in the removal rate of $NO_3{^-}-N$ was observed as the applied voltage increased from 5V to 30V, while no significant increase in the removal rate appeared at the applied voltage beyond 20V during a given operating time. The removal rate appeared to get lower at both acidic and basic condition, compared to neutral pH. Coexistence of of ${SO_4}^{2-}$and $Cl^-$ demanded much longer operating time to achieve a given removal rate or to meet a certain level of treated water concentration. When nitrate ion was combined with ${SO_4}^{2-}$and $Cl^-$, the removal rate was reduced by 4.29% and 10.83%, respectively.

• 한국환경보건학회지
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• 제29권3호
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• pp.59-64
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• 2003

This study was conducted to investigate anoxic-RBC-anoxic-RBC process and its application to remove biologically organics and nitrogen. BOD and total-nitrogen(T-N) removal efficiencies were decreased as volumetric loading rate increased. But, the removal efficiency changes of T-N were little, as compared to BOD. Increase of internal recycle rate had few affect of BOD and T-N removal rates. Also, influent allocation(to 2nd anoxic reactor) had few affect of BOD removal efficiency rate. However, when the influent allocation rate was 30%, T-N removal efficiency was increased to 84.1 %. BOD/N ratio applied to 2nd anoxic reactor was increased to range of 3.65-4.37 as influent allocation rate increased to range 20∼35%. But, it might also cause adverse effect such as decrease of denitrification rate in excessive influent allocation rate.

• KSBB Journal
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• 제13권3호
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• pp.238-243
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• 1998

양어장 순환수 속의 암모니아성 질소의 제거를 위한 Ba-alginate 와 Ca-alginate 반응기는 0.6시간의 수력학적 체류시간에서 51.0, 52.6 g $NH_3-N/m^3/day$의 거의 유사한 암모니아성 집소의 제거속도릎 나타내었다. Ca-alginate를 이용한 합성양어장수 속의 암모니아성 짖소의 제거 실험에서 본 반응기의 암모니아성 짐소의 제거속도는 수력학적 체류시간이 0.3시간인 지점에서 82.0 g $NH_3-N/m^3/day$로 서 최고의 재거속도릎 나타냈으며 이때 암모니아 제거율은 48% 이었다. 수중의 암모니아의 농도가 2mg/L 정도의 범위에서는 반응기 내에 주입되는 공가량을 0.1 vvm 으로 공급하더라도 용존산소 농도를 7.0 - 5.6 g/m3로 유지 할 수 있었으므로 질화에 필요한 용존산소량을 충분히 유지할 수가 있는 것으로 나타났으며 pH 는 7.2 - 7.9의 범위플 유지할 수가 있어서 pH 변화에 따른 위 해 요소는 없는 것으로 나타났다.