• 한국작물학회지
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• 제40권2호
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• pp.185-194
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• 1995

겨울보리 재배 시 질소시비 수준를 달리한 0~30cm, 30~60cm, 60~90cm 근권깊이별 $NO_3^{-}$-N 함량의 경시적 동적 변화를 추적하고 이를 토대로 시료채취 근권깊이를 달리하는 몇몇 토양진단법에 의한 적정 추비량 결정의 국내 적용의 적절성 여부를 검토한 결과, 1 기비 및 추비로 시용된 질소가 표토층으로부터 서서히 심층 하층토로 용탈, 집적되고 있었는데 이는 근권깊이별 $NO_3^-$-N 농도보다 $NO_3^-$-N 함량을 계산할 때에 더욱 명확하였다. 2. 추비직전인 2월말 0~90cm 근권층에서의 $NO_3^-$-N 함량은 기비로 시용한 질소시용 량에 따른 토양내의 $NO_3^-$-N 함량도 비례하여 높아져 기 비 시 용량 차이 가 데 체로 반영 하였으나 0~30cm 근권상층부에서의 $NO_3^-$-N 함량은 기비시용량을 전혀 반영시켜 주지 못하였다. 추비시용 이후의 토양깊이별 $NO_3^-$-N 함량의 경시적 차이 역시 0~30cm에 비해 0~90cm 근권층에서 질소시비량간 차이가 뚜렷하였다. 3. 0~90cm 근권깊이의 $NO_3^-$-N 함량에 따라 질소추비량을 결정하는 $N_{min}$- method에 의해 계산된 질소추비량은 무비구, 보비구, 배비구에서 기비시용량이 많을수록 질소추비량은 80.6, 40.0, 10.1kg/ha로 낮았으며, 보비 구의 경 우 질소추천추비량 60kg/ha보다 20kg/ha 정도 낮았다. 한편 0~30cm 토양진단에 따른 질소추비량은 각 처리구에서 추천시비량의 1차 질소추비량과는 비슷하여 기비처리 수준에 따른 질소추비량 차이가 전혀 없었다. 4. 0~30cm, 0~60cm, 0~90cm 근권 $NO_3^-$-N 함량과 수량과의 관계를 비교한 결과 0~90cm근권 $NO_3^-$-N 함량만이 수량과 높은 정의 상관관계를 나타내 $N_{min}$ 토양진단법이 적절하였다. 한편 0~90cm 근권 $NO_3^-$-N 함량이 120kg/ha일 때 수량이 최고에 도달하였다.

• The Korean Journal of Ecology
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• 제26권6호
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• pp.335-340
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• 2003

Patterns of mass loss and nutrient release from decomposing oak (Quercus mongolica) and mixed litters (Q. mongolica, Betula schmidtii, Acer pseudo-sieboldianum, Kalopanx pictus and Tilia amurensis) in a natural hardwood forest in Gyebangsan (Mt.) were examined using litterbags placed on the forest floor for 869 days. Mass loss rates from decomposing litter were consistently higher in mixed litter (59%) than in oak litter types (52%) during the study period. Nutrient concentrations such as nitrogen (N), phosphorus (P), potassium (K), and magnesium (Mg) from decomposing litter were also higher in mixed litter than in oak litter types. Nutrient concentrations (N, P, Ca, and Mg) increased compared with initial concentration of litter, while K concentrations dropped rapidly at the first 5 months and then stabilized. The results suggest that mas loss and nutrient release obtained from decomposing litter of single species in mixed hardwood forest ecosystem should be applied with caution because of the potential differences of mass loss and nutrient release between single litter and mixed litter types.

• Journal of Microbiology and Biotechnology
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• 제13권5호
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• pp.641-646
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• 2003

An accurate and efficient method for measuring the mass of hairy roots using conductometry is established. A conductivity equation expressed in terms of the concentration of the ion species in the medium is suggested. By using this equation, the effect of the individual ions on the total conductivity can be quantitatively analyzed. An equation for the in situ estimation of the cell growth coefficient for determining the mass of hairy roots is established based on measurements of the nitrogen concentration and conductivity during cultivation. The proposed equation does not require preliminary experiments to determine the cell growth coefficient. Instead, the physiological characteristics of the plant species are reflected by introducing the cellular nitrogen content. Since the cell growth coefficient is determined by measuring the major ionic nutrient concentrations, it is more effective to express the dynamics of an actual culture system. This improved method for determining the mass of hairy roots was successfully utilized in a fed-batch culture system.

• Journal of Photoscience
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• 제6권3호
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• pp.141-144
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• 1999

A Spectroscopic study on a pulme produced by a reactive laser pulse irradiates the graphite target in a nitrogen atmosphere, two emission bands of C2(d3IIg longrightarrowa3 IIu, Swan band) and CN(B2$\Sigma$+ longrightarrowX$^2$$\Sigma$+, Violet band ) were observed. By simulation of the optical emissionspectra, spectroscopic temperature of $C_2$ and CN molecules were obtained. The depended of vibrational and rotational temperatures on the laser fluence and distance from the target as well as the pressure dependence of the emission intensities of $C_2$ and CN was examined to elucidate the expansion dynamics of the plume and formation mechanisms of $C_2$and CN molecules.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2005년도 춘계학술발표회 요지
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• pp.82-83
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• 2005

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2002년도 추계 학술대회논문집
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• pp.144-149
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• 2002

This paper presents the result of numerical simulation of particles trace following melted zinc movement with nitrogen gas injection. The code of the computational fluid dynamics for numerical analysis was performed using FLUENT related to CFD. As application model, there was applied Eulerian multiphase model for simulation of melted zinc movement at first and then was used stochastic tracking technique for particles trace secondarily. Numerical simulation results are shown that particles move to the same direction as the movement of melted zinc.

• 한국작물학회:학술대회논문집
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• 한국작물학회 1994년도 추계 학술대회지
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• pp.44-45
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• 1994

• The Korean Journal of Ecology
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• 제17권4호
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• pp.501-511
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• 1994

Dynamics of nutrients, non-polar, water solubles, acid solubles and acid insolubles (lignin) in decomposing litter were investigated for 2 years in the oak, Quercus acutissima, and the pitch pine, Pinus rigida, stands in the vicinity of Kongju, Chungnam Province. Nitrogen and phosphorus conetrations in decomposing litter increased with time elapsed, however, potassium decreased rapidly within three months and then remined constant with time elapsed. Calcium concentration in needle litter during experimental period was lower than that of initial concentration in needle litter during experimental period was lower than that of initial concentration, and showed no significant variation with time elapsed. Calcium concentration in oak litter during the experimental period, however, were higher than that of initial concentration. Magnesium concentration in oak litter decreased repidly during six months, and then remaines constant thereafter. Annual amount of nitrogen, phosphorus, potassium, calcium and magnesium which returned to soil via litter decomposition in the oak and the pitch pine stands was $3.3g/m^2$ and $0.9g/m^2$ for N, $0.03g/m^2$ and $0.01g/m^2$ for P, $1.3g/m^2$ and $0.7g/m^2$ for K, $0.7g/m^2$ and $1.2g/m^2$ for Ca, $0.9g/m^2$ and $0.4g/m^2$ for Mg, respectively. Non-polar, and water- and acid-soluble fractions in decomposing litter decreased and lignin increased with time.

• ALGAE
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• 제17권2호
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• pp.95-104
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• 2002

Population dynamics of Anabaena and the anatoxin-a concentration were monitored with physicochemical parameters at 3 sites in the lower Naktong River from May to September in 2000. Total 4 species of Anabaena (A. flosaquae, A. smithii, A. ucrainica and A. mucosa) were identified with morphological characterisitcs. Anabaena flos-aquae was most abundant among the populations. The standing crop of Anabaena ranged from 10 to 11,220 cells · $ml^{-1}$ and biomass of Anabaena more 1,000 cells · $ml^{-1}$ was obseved once at St. Mulgeum and St. Seonam, twice at St. Hagueon out of total 9 samplings. There were not significant correlations between the standing crop of Anabaena and other physicochemical parameters such as temperature, nitrate, total nitrogen, phosphate, total phophorus and N/P ratios. The frequency of trichomes with akinetes was low and ranged from 0 to 4% in the total Anabaena population and A. smithii showed highest frequency of 2.8% among all species. The population at St. Seonam showed highest frequency of 1.4% among all sampling sties. The population in September showed the highest frequency of 3.0% among all sampling period. The frequency of trichomes with heterocysts was low and ranged from 1 to 87% inthe total Anabaena population and A. smithii showed highest frequency of 55.1% among all species. The population at St. Mulgeum showed highest frequency of 17.6% among all sampling sites. The population in August showed the highest frequency of 21.4% among all sampling period. The frequency of trichomes with akinetes and/or heterocysts was not related to all the physicochemical parameters of temperature, nitrate, total nitrogen, phosphate, total phosphorus and N/P ratios. The anatoxin-a concentations were determined in algal materials dominated by Microcystis and Anabaena from June though August by derivatization using 7-fluoro-4-nitro-2, 1,3-benzoxadiazole (NBD-F) and HPLC analysis with fluorimetric detection. All the concentrations were below the detection limit of 0.1 ㎍ · $l^{-1}$ in the present study.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
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• pp.175-178
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• 2004

Little study has been published specifically addressing the dynamics of nitrate reducing bacteria (NBR) during the bioremediation of nitrate-contaminated aquifer. In our previous study we successfully quantified fumarate-enhanced microbial nitrate reduction rate in a nitrate-contaminated aquifer by using a series of single-well push-pull tests (PPTs). In this study we analyzed the suspended population during PPTs. To monitor changes in the microbial community, PCR amplification of 16S rDNA genes and denaturing gradient gel electrophoresis (DGGE) were used to study the dynamics of the bacterial community in detail. Before the stimulation of NBR, the dominant DGGE bands obtained by PCR were affiliated with V-Proteobacteria consisting of Acinetobacter spp. and Pseudomonas fluorescens. However, as NBR biostimulation proceeded, the dominant patterns of DGGE bands changed, and they were affiliated with Azoarcus denitrificans Td-3 and Flavobacterium xanthum. Azoarcus denitrificans Td-3 is known to completely reduce nitrate to nitrogen gas. The series of single-well push-pull tests in this study should prove useful for conducting rapid, low-cost feasibility assessments for in situ denitrification and provide important information about which microorganisms play a key role in bioremediation of a nitrate contaminated aquifer.