• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.219.1-219.1
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• 2010

매립지에서 유기물의 분해로 발생되는 매립가스는 악취 등으로 인한 대기오염뿐만 아니라 온난화지수가 21인 메탄이 약 50vol% 포함되어 있어 지구온난화에 큰 영향을 미친다. 하지만 매립가스를 에너지원으로 활용하면 대기오염저감, 지구온난화 감소, 대체에너지원 확보뿐만 아니라 CDM사업 등과 연계하여 부가수익창출이 가능하다. 현재 국내에는 약 242개의 폐기물매립지가 있는데, 이중 매립가스를 활용하는 곳은 단지 14개소로 개별 경제성이 있는 대형매립지에서만 자원화시설을 설치하여 운영 중이며 그 외 매립지에서는 매립가스를 소각 또는 단순 대기 방출하여 대기오염유발과 동시에 대체에너지원 미활용으로 국가차원에서 큰 손실이므로 이를 활용할 수 있는 기술개발이 시급하다. 본 연구에서는 중소규모 매립지에서 발생하는 매립가스를 중심적환장으로 이송하여 경제성을 가지는 에너지원으로 활용할 수 있는 기술개발을 목표로 하이드레이트 기술을 접목한 기초연구를 수행하였다. 매립지에서 매립가스가 생성되는 과정에 표층부의 균열 및 차수막의 손상과 포집하는 공정에서 블로워 등의 사용으로 질소가 다량 포함되며 질소의 경우 상당히 높은 압력과 낮은 온도에서 하이드레이트를 형성하므로, 매립가스 하이드레이트 형성시 질소의 영향에 대해 알아보았다. $CH_4+CO_2$ System과 $CH_4+O_2+N$ System에 대하여 각각의 실험조건에서 Kinetic을 측정하였으며, 실험전후의 가스 조성을 Gas Chromatography로 정성, 정량 분석하였다. 실험결과 매립가스에 공기가 유입될 경우, 질소의 영향으로 하이드레이트 생성조건이 가압되었고 하이드레이트 내 메탄의 함량비율이 줄어들었다.

• Applied Chemistry for Engineering
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• v.9 no.3
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• pp.383-387
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• 1998

The effect of hydrophilic surface modification of low density polyethylene(LDPE) byt the plasma gas($O_2$, $N_2$, and $O_2/N_2$) was investigated from the point of view of the functionalities of the generated LDPE surfaces and the contact angle. By virtue of x-ray photoelectron spectra(XPS) and attenuated total reflectance(FT-IR ATR) analysis, the LDPE surfaces treated with plasma were generated with oxygen functionalities of carbonyl, carboxyl, and the like, nitrogen functionalities by nitrogen plasma and mixing of nitrogen and oxygen plasma treatment were identified with. It was found that nitrogen plasma treatment showed with minimum value at contact angle for rf-power and treatment time, we had obtained optimum condition for hydrophilic surface modification at composite parameter, [(W/FM)t] 520~550GJs/kg.

• Applied Biological Chemistry
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• v.35 no.3
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• pp.202-209
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• 1992

In order to study on the viscous substance produced during Chungkookjang fermentation, one strain which produce a lot of viscous substance was isolated from the rice straw and identified as Bacillus sp; This strain produced the most viscous substance in 48 hours at $42^{\circ}C$, in splite of little change of amino type nitrogen and ammonia type nitrogen when added M.S.G., while the yield of viscous substance and amino type nitrogen was increased but that of ammonia type nitrogen was decreased when added susrose. Molecular weight of viscous substance estimated between 15,000 and 65,000. Viscous substance was confirmed mostly composed of glutamate and fructose by G.C. and HPLC analysis. Composition of viscous substance would be controlled according to the changes of media.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.3
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• pp.215-222
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• 1995

Nb doped strontium titanate single crystals were grown by the floating zone method. The doping amount of $Nb_2O_5$ was 0.2 wt %. Those crystals were grown in air and N z atmosphere and the growth rate was 5 mmlhr and rotation speed of upper and lower shaft was 30 rpm. The shapes of melt - feed rod interface depending on sintering temperatures were observed. In air atmosphere, the flow rate of air was 1.5 ${\ell}/min$ and in $N_2$ atmosphere, that of $N_2$ gas was 0.5 ${\ell}/min$. As grown crystals were analyseQ by XRD, Laue back - reflection and chemical etching. After annealing in $N_2$ atmosphere, resistivities of crystals were measured and the activation energies of each samples were calculated.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.7 no.1
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• pp.37-40
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• 1974

The chemical constituents of the cooked-released fluid of oyster, Crassosetra gigas which was collected in the harvesting season (Sept., 1973 to Apr., 1974), were analyzed Periodically to evaluate the potential utility in the view point of food and nutrition, an8 the following results are summarized ; 1. The content of crude protein nitrogen was low in January, but tended to increase since February. This result resembled with non protein nitrogen. 2. Amino nitrogen of the non protein nitrogen was continuously increased since September, and observed a remarkable increase from February. 3. The most content of crude carbohydrate is found to be composed of glycogen, and the variation of glycogen content also increased till April, with the similar tendency of amino nitrogen. 4. The variation of the content of crude protein and crude carbohydrate showed a reverse correlation to the moisture content.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.3
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• pp.635-644
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• 1994

A mathematical model was developed to predict the concentrations of various nutrients in supernatants during aerobic digestion which is suitable to be employed in small wastewater treatment plants with such advantages as low capital cost and stable process. Significant reactions were determined with observing the behavior of nitrgen and phosphorus, and the model equations were built up in the form of simultaneous differential equations considering Mass Balance. Laboratory batch experiments were carried out at $20^{\circ}C$ and pH $7.5{\pm}0.5$ on the aerobic digestion of waste activated sludge at different solid levels. Nonlinear regression analysis was performed to estimate various reaction rate constants. The developed model can predict the behavior of Biomass N, dissolved organic N, $NH_4{^-}$-N, $NO_x{^-}$-N, and Biomass P, dissolved organic P, $PO_4{^-}$-P in aerobic digestion process. In this study, the results of simulation showed that dissolved nutrients had more effects on supernatants than nutrients in biomass, and phosphorus was more effective on supernatants than nitrogen.

• Korean Chemical Engineering Research
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• v.50 no.6
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• pp.1043-1048
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• 2012

In this study, activated carbons (ACs) were modified as electrode materials for an electric double layer capacitor (EDLC) by controlling oxygen- and nitrogen-containing functional groups. The morphological and chemical properties of ACs were analyzed through scanning electron microscopy (SEM), fourier transform infrared (FTIR) spectrometer, automatic elemental analyzer (EA) and Boehm titration. Also, charge/discharge tests were performed to investigate the EDLC performance. Oxygen- and nitrogen-containing functional groups were introduced on the surface of ACs through acid and urea treatments, respectively. ACs with nitrogen-containing functional groups showed 2 mA increase of gravimetric discharge capacity and quick achievement of maximum charge/discharge performance. However, ACs with oxygen-containing functional groups showed low discharge capacity and its gradual decrease during further cyclic test, since the functional groups interrupted adsorption/desorption of charges in the electrolyte on the surface of ACs.

• Journal of Animal Environmental Science
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• v.1 no.2
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• pp.165-171
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• 1995

Aerobic treatment of animal slurries represents an increasingly popular option for farmers in the management of animal wastes. This study was performed to find out the chemical characteristics of dairy slurry associated with liquid-solid separation. Total solids concentration varies widely depending on the slurry manure handling systems. Hydrogen ion exponent(pH), volatile solids(VS), ammonia nitrogen(NH$_3$-N), nitrate nitrogen (NO$_3$-N), and chemical oxygen demand(COD) essentially depends on the total solids content of animal liquid wastes. Total solids content of the dairy slurry ranges from 6.6 to 7.5% depending on the feed slurry and separator. Separated liquids from dairy slurry have been successfully downed for up to about 21, 900mg/$\ell$ of the COD value. It has also been found that separated slurry decreased from 37.8 to 26.0mg/$\ell$ of the NO$_3$-N concentration.

• Journal of the Korean Applied Science and Technology
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• v.30 no.2
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• pp.348-355
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• 2013

Squid ink was added to the salt fermented squid by 2% or 4% of concentration and ripened at $10^{\circ}C$ for 8 weeks and at $20^{\circ}C$ for 32days. The effects of the squid ink on the amino nitrogen and muscle protein of salt fermented squid were investigated. The results are as follows; As the salt concentration was decreased and the fermentation temperature raised, amino nitrogen in the salt fermented squid without addition of the squid ink was significantly increased to the latter stage of the ripening and hence fermentations were enhanced. From the change of the protein in the squid muscle in the experiments, dissolution of the myosin heavy chain took place conspicuously in the early stage of the ripening while actin was rarely changed which resulted in the strong resistance to protease. The amino nitrogen content in the salt fermented squid addition of the squid ink has increased to the latter part of the ripening but the range was smaller than no treatment groups. The protein in squid muscle, especially the myosin heavy chain was remarkably dissolved in the middle of the ripening whereas the squid ink added groups of high salt concentration and low temperature showed the tendency of slow proteolysis.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.1
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• pp.42-48
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• 2014

In this study, variations of the organic and nitrogenous compounds in wastewater were investigated in a single reactor with intermittent aeration. Over 90% of organic and nitrogen removals are accomplished with C/N ratio of 3 : 1 and 20/20 min of aeration/non-aeration period. Longer non-aeration period on the aeration/non-aeration cycle showed more stable nitrogen removal, showing various microbial community in the reactor. From PCR-DGGE analysis, it is conclusive that Dysgonomonas mossii strain Melo40, Eubacterium sp. oral clone JN088, Uncultured bacterium clone SPESB2_718, and Bacterium enrichment culture clone LE are related with the organics and nitrogen oxidation. Uncultured Acidobacteria bacterium clone AKYG487, Lactobacillus harbinensis strain FQ003, Erythrobacter litoralis strain Gi-3, Phytobacter diazotrophicus strain Ls8, and Mycobacterium sp. enrichment culture clone GE10037biofNNA are distinctly appeared under denitrification condition.