• Journal of Korean Society of Environmental Engineers
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• v.22 no.10
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• pp.1893-1904
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• 2000

Nitrogen compounds are one of the major pollutants which cause eutrophication problems of the river or lake and red tides problems of the ocean. Currently available technologies for the removal of nitrogen compounds are mostly biological treatment. However, biological treatment is only effective for the wastewater which contains low concentration of nitrogen compounds. Leachate from solid waste landfill or industrial wastewater which contains high concentration of nitrogen can not be effectively treated by most of the currently available biological treatment technologies. With this connection. the objective of this study is to examine the applicability of ammonia stripping technology for the removal of high concentration of ammonia nitrogen compounds of the leachate from solid waste landfill. It can be concluded that ammonia stripping technology which was placed before the biological treatment process was very effective for the removal of high concentration of ammonium compounds. The chemical cost for the ammonia stripping was 16 percent higher than MLE process, so other methods like sludge recycling are needed for the reduction of operation cost. Further details are discussed in this paper.

• Journal of the Korean Chemical Society
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• v.35 no.6
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• pp.659-666
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• 1991

A systematic analysis of 18 stimulants and narcotic analgesics containing nitrogen atom (s) in human urine by gas chromatography with nitrogen phosphorus detector (GC-NPD), is described. The urinary extract with diethyl ether at pH 8.5 showed good recoveries of the drugs and less interference peaks on GC chromatogram. Retention data were standardized by the calculation of relative retention times using diphenylamine as the internal standard. The relative standard deviations of retention times were less than 0.1% for the within-run analyses. The response factor (RRF) of a drug relative to the internal standard was calculated. RRF decreased with increasing number of nitrogen atoms. This technique can be adapted to various analytical toxicology problems.

• Resources Recycling
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• v.19 no.1
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• pp.21-26
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• 2010

In order to understand the microwave carbothermic reduction of steelmaking slag to recover Fe, the effects of gas atmosphere and carbon addition on the carbothermic reduction behavior of CaO-$SiO_2$-FeO slag were investigated. It was found that the maximum temperature and the reduction rate were higher in air than in nitrogen atmosphere. In addition, under air atmosphere, the maximum temperature and the reduction rate were increased by increasing the amount of additive carbon. When the carbon equivalent is 5, the maximum temperature reached as high as 1800K and the reduction rate was approximately 90%. As the Carbon equivalent increased further, the maximum temperature and the reduction rate did not change.

• Korean Journal of Soil Science and Fertilizer
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• v.33 no.5
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• pp.325-332
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• 2000

To determine the distribution and recovery of fall-applied N in various parts of satsuma mandarins (Citrus unshiu Marc). $19.68g\;N\;tree^{-1}$ as urea containing 5 atom % $^{15}N$ and 58 kg$K_2O$ $ha^{-1}$ were broadcast-applied to 11 years old 'Miyagawa Wase' grown at a spacing of $2.7{\times}2.7m$ on 18 November 1998. Nitrogen, $P_2O_5$, and $K_2O$ were applied at 104, 308, and $62kg\;ha^{-1}$ on 22 March and N and $K_2O$ at 42 and $83kg\;ha^{-1}$ on 15 June 1999. Two trees were excavated on 15 June and 8 December 1999, respectively. In mid-June, whole tree contained $168.2g\;N\;tree^{-1}$ of which 11.9, 42.1, 29.7, and 16.3% were in fruits, leaves, stems, and roots, respectively. In early December, total tree N averaged $169.8g\;tree^{-1}$ and fruits accounted for 27.6%, leaves 36.4%, stems 22.8%, and roots 13.2% of total tree N. Regardless of harvest date, N derived from fertilizer was highest in newly developed tissues. In mid June, the tree recovered 18.5% ($3.63g\;tree^{-1}$) of fertilizer N. Fruits accounted for 21.1%, leaves for 50.4%, stems for 21.5%, and roots for 7.9% of fertilizer-derived N in the tree, respectively. In early December, the tree recovered 17.0% of fertilizer N. Fruits contained 39.6%, leaves 40.5%, stems 14.5%, and roots 5.3% of fertilizer-derived N in the tree respectively. Comparing with total tree N, a higher proportion of fertilizer-derived N was allocated to metabolically active tissues while a less proportion to old tissues regardless of harvest date.

• Korean Journal of Medicinal Crop Science
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• v.3 no.2
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• pp.100-106
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• 1995

This study was conducted to find the factors affecting somatic embryogenesis in suspension culture of Rehmania glutinosa and investigate the possibility of artificial seed production by encapsulation of somatic embryos. Linsmeier-Skoog medium was appeared as proper for somatic embryogenesis. Sucrose with $3{\sim}5%$ as carbon sources was good for somatic embryogenesis, and both ammonium and nitrate nitrogen were necesary for normal somatic embryo production. BA with NAA or kinetin with NAA were better than the use of cytokinin alone for both somatic embryogenesis and numbers of somatic embryos. $AgNO_3$ as protectant for vitrification of seedlings in vitro culture had no harmful effect on somatic embryos. Sphericity of encapsulated seeds was good at 3% gel of sodium alginate but germination was better at 2.5% sodium alginate level. Artificial seeds were germinated and developed normal shoots and roots under in vitro condition.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.5
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• pp.386-395
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• 2006

The core questions for determining nitrogen topdress rate (Npi) at panicle initiation stage (PIS) are 'how much nitrogen accumulation during the reproductive stage (PNup) is required for the target rice yield or protein content depending on the growth and nitrogen nutrition status at PIS?' and 'how can we diagnose the growth and nitrogen nutrition status easily at real time basis?'. To address these questions, two years experiments from 2001 to 2002 were done under various rates of basal, tillering, and panicle nitrogen fertilizer by employing a rice cultivar, Hwaseongbyeo. The response of grain yield and milled-rice protein content was quantified in relation to RVIgreen (green ratio vegetation index) and SPAD reading measured around PIS as indirect estimators for growth and nitrogen nutrition status, the regression models were formulated to predict PNup based on the growth and nitrogen nutrition status and Npi at PIS. Grain yield showed quadratic response to PNup, RVIgreen around PIS, and SPAD reading around PIS. The regression models to predict grain yield had a high determination coefficient of above 0.95. PNup for the maximum grain yield was estimated to be 9 to 13.5 kgN/10a within the range of RVIgreen around PIS of this experiment. decreasing with increasing RVIgreen and also to be 10 to 11 kgN/10a regardless of SPAD readings around PIS. At these PNup's the protein content of milled rice was estimated to rise above 9% that might degrade eating quality seriously Milled-rice protein content showed curve-linear increase with the increase of PNup, RVIgreen around PIS, and SPAD reading around PIS. The regression models to predict protein content had a high determination coefficient of above 0.91. PNup to control the milled-rice protein content below 7% was estimated as 6 to 8 kgN/10a within the range of RVIgreen and SPAD reading of this experiment, showing much lower values than those for the maximum grain yield. The recovery of the Npi applied at PIS ranged from 53 to 83%, increasing with the increased growth amount while decreasing with the increasing Npi. The natural nitrogen supply from PIS to harvest ranged from 2.5 to 4 kg/10a, showing quadratic relationship with the shoot dry weight or shoot nitrogen content at PIS. The regression models to estimate PNup was formulated using Npi and anyone of RVIgreen, shoot dry weight, and shoot nitrogen content at PIS as predictor variables. These models showed good fitness with determination coefficients of 0.86 to 0.95 The prescription method based on the above models predicting grain yield, protein content and PNup and its constraints were discussed.

• Proceedings of the KAIS Fall Conference
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• 2010.11a
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• pp.291-293
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• 2010

알카리성 과황산칼륨을 이용한 자외선 흡광광도법은 수중의 총질소를 간편하면서도 신속하고 정확하게 분석할 수 있는 방법으로 각각의 질소성분을 standard method에 의해 분석한 후 이들을 합산하는 방법보다 회수율이 좋게 나타났다. 자외선 흡광광도법을 이용할 경우 Cr(VI)이온과 Br이온에 의해 방해를 받으므로, Br이온을 다량 함유하는 해수의 총질소 분석방법으로는 적합하지 않은 것으로 관찰되었다. 전처리를 한 후 220 nm에서 흡광도를 측정하기 위해서는 탄산염의 방해를 방지하기 위해 pH를 2~3으로 조절한 후 분석해야만 하고, 알카리성 과황산칼륨을 이용한 자외선 흡광광도법은 총질소를 분석하는 방법으로 우수성이 입증되었으나 각 형태별 질소의 농도를 측정할 수 없는 단점이 있으므로 각 형태별 질소의 농도를 측정하기 위해서는 standard method를 이용해야 된다. 본 연구에서 알카리성 과황산칼륨을 이용한 자외선 흡광광도법은 총질소를 분석하는데 있어서 standard method에 의한 합산법보다 시간과 노력을 절약할 수 있는 것으로 검토되었다.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2008.11a
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• pp.517-521
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• 2008

Struvite의 최적 생성조건은 NH$_4$-N의 초기농도에 관계없이 모두 NH$_4^+$, PO$_4^{3-}$ 및 Mg$^{2+}$가 등몰비이고 pH 10.5이었다. Struvite 침전반응에서 NH$_4$-N 및 PO$_4$-P 제거율에 미치는 struvite seeding 효과는 습윤상태의 struvite를 seeding할 경우 그 효과가 거의 없었으나 건조된 struvite를 seeding할 경우 NH$_4$-N의 제거율은 증가되지만 PO$_4$-P의 제거율은 감소되는 경향을 나타냈다. 이는 건조과정에서 struvite의 NH$_4$-N가 휘산되어 소실되었기 때문이다. Mg와 P원으로서 struvite의 재이용을 위한 적정 건조온도는 100$^{\circ}C$ 이하였으며 그 이상 온도에서는 struvite가 $NH_4MgPO_4\cdot6H_2O$형에서 MgPO$_4$형으로 상전이점에 따라 struvite seeding에 의한 NE$_4$-N의 제거율이 현저히 감소되었다. 건조된 struvite는 초기 NH$_4$-N의 몰농도 대비 50%를 seeding할 경우 60% 이상의 NH$_4$-N를 제거하였으며, seeding량을 150%로 증가시킬 경우 90% 이상의 NH$_4$-N 제거율을 얻을 수 있었다. 그러나 struvite를 반복 재사용할 경우 재사용 횟수에 비례하여 NH$_4$-N의 제거율은 감소하는 경향을 보여 재사용 횟수가 제한적임을 알 수 있었다.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.24 no.3
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• pp.85-102
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• 1979

In spite of the expansion of population as well as the improvement of living standard, the sugar consumption in Korea depends totally upon the imported sugar with no domestic production. In order to solve this current problem, the author carried out series of experiments and investigations in Daegwanryeong area best suitable for sugar beet cultivation to determine the good varieties, cultivation method, distribution of cultivation area. Thus, it is expected that the result of investigation make a small contribution to the enterprise or production.

• Korean Journal of Food Science and Technology
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• v.6 no.1
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• pp.12-16
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• 1974

The amino acid pattern of embryo and endosperm of brown rice different in specific gravity was investigated using Jinheung (local leading temperate variety) and IR667-Suweon 213 (high-yielding newly bred tropical variety). 1. Embryo of IR667 (higher protein rice) showed lower protein, and lower lysine or essential amino acid per protein than that of Jinheung (lower protein rice). 2. In both embryo and endosperm nitrogen recovery as amino acids was highest in middle class of specific gravity and lowest in low class indicating that abundancy of non-protein nitrogen in low class and decomposition of amino acids by starch in high specific gravity class. 3. In both embryo and endosperm IR667 showed abundancy in order of glutamic acid, aspartic acid while Jinheung showed glutamic acid, arginine, suggesting varietal difference in nitrogen metabolism. 4. In both IR667 and Jinheung least amino acid was histidine and next leucine in embryo but histidine and next threonine in endosperm, suggesting organ difference in nitrogen metabolism.