• Bulletin of the Korean Chemical Society
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• v.35 no.1
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• pp.165-172
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• 2014

The distribution of basic nitrogen-containing compounds in three vacuum gas oils (VGOs) with different boiling ranges and their dewaxed oils from the lube base oil refining unit of a refinery were characterized by positive-ion electrospray ionization (ESI) Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS). It turned out that the composition of basic nitrogen compounds in the samples varied significantly in DBE and carbon number, and the dominant basic N-containing compounds in these oil samples were N1 class species. $N_1O_1$, $N_1O_2$, and $N_2$ class species with much lower relative abundance were also identified. The composition of basic nitrogen compounds in VGOs and dewaxed VGOs were correlated with increased boiling point and varied in DBE and carbon numbers. The comparison of the analytical results between VGOs and dewaxed VGOs indicated that more basic N-containing compounds in VGO with low carbon number and small molecular weight tend to be removed by solvent refining in lube base oil processing.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.3
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• pp.420-426
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• 1995

Volatile compounds in raw oyster and oyster hydrolysate produced with protease were compared by vacuum simultaneous steam distillation-solvent extraction/gas chromatography/mass spectrometry. Sixty-two volatile compounds were detected in both samples. Of these, 57 were positively identified, composed mainly of aldehydes(12), ketones(9), alcohols(14), nitrogen-containing compounds(9), acids(6), terpenes(4), and miscellneous compounds(8). Levels of acids decreased after hydrolysis, whereas several other compounds such as aldehydes, ketones, and nitrogen containing compounds increased. Pyrazines, found in high abundance, were only detected in oyster hydrolysate.

• Journal of Korean Society for Atmospheric Environment
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• v.21 no.6
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• pp.657-666
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• 2005

The objectives of this study were to investigate atmospheric dry deposition of inorganic nitrogen-containing compounds to waterbody. Target waterbody is Juam reservoir functioning as one of the major water supply sources in Chollanamdo. Nitrate and ammonium dry deposition fluxes were directly measured using dry deposition plate (DDP) covered with greased strips and a water surface sampler (WSS). The daytime average $NO_{3}^{-}\;and\;NH_{4}^{+}$ fluxes measured with DDP and WSS were $1.7\∼2.6$ times higher than those at nighttime. The seasonal average flux of $NH_{4}^{+}$ showed the highest value in summer. The daytime and nighttime average dry deposition fluxes of particulate phase Nitogen-containing Compounds ($1.13,\;0.80\;mg/m^{2}$ day) were much higher than those of gas phase compounds ($0.50,\;0.24\;mg/m^{2}$ day).

• Journal of Environmental Health Sciences
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• v.36 no.3
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• pp.222-228
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• 2010

Biological degradation of nitrogen-containing aromatic compounds was investigated in activated sludge previously adapted to mineralize low concentrations of nitrogen-containing aromatic compounds. Normally, the time required for 95% degradation of 10 mg/l dinitrophenol (DNP) under aerobic conditions was less than 4 hours without any lag, and with mixed liquor suspended solid (MLSS) levels from 600 to 1,000 mg/l. However, when the initial DNP concentration was increased to 75 mg/l, lags and even complete inhibition of DNP degradation were observed. The length of the lag was found to increase proportionally with decreasing MLSS levels. When dilute activated sludge was incubated for extended periods (192 hours), degradation of 75 mg/l DNP did eventually occur after lag periods of 37 to 144 hours, depending on the MLSS concentration. DNP was degradable in high concentrations if MLSS concentrations were sufficiently high to allow growth of bacteria resistant to the toxic effects of DNP.

• Preventive Nutrition and Food Science
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• v.3 no.1
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• pp.15-21
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• 1998

Volatile flavor compounds in hydrolyzed blue mussel(HBM) produced by OptimaseTM APL-440, with untreated blue mussel(UBM) were compared. A total of 100 volatile compounds were detected in both HBM and YBM , consisting mainly of 25 aldehydes, 16 ketones, 17 alcohols, 8 nitrogen-containing compounds, 11 aromatic compounds, 8 terpenes, and 15 miscellaneous compounds. Levels of aromiatic compounds decreased after hydrolysis, whereas levels of 7 nitrogen-containing compounds increased. The compounds , 3-methylbutanal, (z)-4-heptenal, and (E,Z)-2-, 6-nonadienal , had the highest odor values in both samples. Total free amino acids in HBM were 21.89%(w/w) and increased by 3,4 times higher than UBM. glutamic acid and aspartic acid, having sour tastes, were the major taste-active compounds in HBM.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.4
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• pp.775-784
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• 2000

Nitrate dry deposition fluxes were directly measured using knife-leading-edge surrogate surface (KSS) covered with greased strips and a water surface sampler (WSS). The average gaseous flux ($8.3mg/m^2/day$) was much higher than the average particulate one ($3.0mg/m^2/day$). The best fit gas phase mass transfer coefficient (MTC) of $HNO_3$ was obtained by linear regression analysis between measured gaseous flux containing nitrogen compounds and measured ambient $HNO_3$ concentration. The result showed that the MTCs of $HNO_3$ were approximately two times higher than those of $SO_2$. Especially, during the ozone action day, measured gaseous fluxes containing nitrogen compounds were much higher than those ones calculated as the product of measured ambient $HNO_3$ concentration and gas phase MTC of $HNO_3$, which is calculated from MTC of $SO_2$ using Graham's diffusion law. This result indicated that other nitrogen compounds except $HNO_3$ contributed to gaseous flux containing nitrogen compounds into the water surface sampler. The theoretical calculations suggest the contributions of nitrous acid ($HNO_2$) and PAN to the gaseous dry deposition flux of nitrogen containing compounds to the WSS.

• Journal of the Korean Society of Food Culture
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• v.12 no.1
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• pp.63-69
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• 1997

This study was carried out in order to analyzed the changes in nitrogen containing taste compounds of three different types of traditional Korean soy sauce with varing ripening period, and to investigates correlation between sensory characteristics and taste compounds contents via contents assay and sensory evaluation of soy sauce samples. Total nitrogen, ammonia type nitrogen and amino type nitrogen contents showed the highest value in Kyupjang. 17 kinds of free amino acid was detected in Chungjangs and 16 kinds of free amino acid was detected in Kyupjang. Nucleotides and their related compounds detected were hypoxanthin, xanthin, IMP, AMP, Inosine, ADP. Free amino acid and nucleotides and their related compounds contents were highest in Kyupjang. Nitrogen related compounds content of high concentration soy sauce ripened over 150 days increased similarly with Kyupjang. In the sensory evaluation of soy sauce taste, Chungjang samples acquired the highest score in the offensive taste test while Kyupjang marked highest score for sweet taste, nutty taste, taste preference. High concentration soy sauce ripend over 150 days yielded the result similar to that of Kyupjang. Sweet taste showed positive correlation with nitrogen compounds. The materials that showed positive correlation with nutty and traditional soy sauce taste and taste preference were nitrogen compound, IMP, AMP. Except for tryptophan, all free amino acid showed positive correlation with nutty and traditional soy sauce taste. Particulary, taste preference correlated to lysine, aspartic acid and glutamic acid.

• Journal of environmental and Sanitary engineering
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• v.8 no.1
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• pp.81-91
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• 1993

This paper was carried out to isolate and identify Aeromonas caviae which can degrade Sodium Dodecyl Benzene Sulfonate(SDBS) effectively. And the affecting factors for the ability of bacterial degradation were also studied. Frm October 1991 to February 1992, two hundred samples from sweage in Taegu area and Nakdong river waters in Talsung Gun area were tested. Minimal salt medium which contain SDBS only as a carbon source was used as a culture medium. The isolated new strain was identified as Aeromonas caviae Kim & Kweon. The optimal pH for SDBS degradation were 7.0 and temperature, $32^{\circ}C.$ It was taken 24 hours to degrade SDBS of 20mg/l completely under the optimal pH and temperature. And in the case of 30 mg/l of SDBS, it was taken 36 hours. The nitrogen sources were added to the minimal salt media containing 20mg/l of SDBS, and they were incubated at $32^{\circ}C$ for 14 hours. 86.9% SDBS were degraded after addition of 0.03% peptone as a organic nitrogen source. And 70.5% SDBS after addition of 0.05% ammonium sulfate as a inorganic nitrogen source. In the case of metal compounds(0.015%), the degradation rate for SDBS were 3.5 fold increased in the media containing magnesium chloride and calcium chloride than in the media that were not containing these metal compounds. And where the media containing magnesium chloride was 0.05%, the degradation rate was 65.8%. And above 0.3% NaCI, the degradation rate was decreased slowly.

• Applied Chemistry for Engineering
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• v.33 no.4
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• pp.431-435
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• 2022

The reduction of nitrogen-containing compounds (NC) containing the model crude methylnaphthalene oil (CMNO) of 5 compounds system was experimentally studied by solvent extraction. The model CMNO consisting of 3 kinds of NC including quinolone (QU), iso-quinoline (IQU), indole(IN) and 2 kinds of bicyclic aromatic compounds such as 1-methylnaphthalene (1MNA), 2-methylnaphthalene (2MNA) as raw materials, as well as the aqueous solution of formamide as a solvent, were used. The increase in the volume fraction of water to the solvent at the initial state (y_w,0) sharply decreased, but the distribution coefficient and the yield of NC conversely increased the selectivity of NC based on 2MNA, and an increase in the volume fraction of solvent to feed (S/F) simultaneously increased the distribution coefficient, yield and selectivity of NC. The yields of QU, IQU and IN under constant conditions (y_w,0 = 0.1, S/F = 1, equilibrium temperature 303 K) were 30%, 31% and 10%, respectively, and selectivity was 15, 15 and 20, respectively. From the excellent yield and selectivity of NC, the formamide extraction method of this study was expected as a method for reducing the NC contained in the model CMNO.

• Korean Journal of Materials Research
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• v.29 no.11
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• pp.677-683
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• 2019

In this paper, nitrogen-doped reduced graphene oxide(rGO) is obtained by thermal annealing of nitrogen-containing compounds and graphene oxide (GO) manufactured by modified Hummers' method. We use melamine as a nitrogen-containing compound and treat GO thermally with melamine at over $800{\sim}1,000^{\circ}C$ and 1 ~ 3 hr under Ar atmosphere. The electrical conductivity of doped rGO is measured by 4-point probe method. As a result, nitrogen contents on rGO are found to be in the range of 2.5 to 12.5 at% depending on the doping conditions after thermal annealing. The main doping site on graphene oxide is changed from pyridinic-N and pyrrolinic N to the graphitic site as the heat treatment temperature increases. The electrical conductivity of doped rGO increases as the N doping content increases. As the thermal treatment time increases, the change of both total doping contents and doping sites is slight and the surface resistance is remarkably reduced, which is caused by healing effects of doped graphene oxide at high temperature.