• Title, Summary, Keyword: N-containing compound

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Synthesis of Nitrogen-Doped Graphene by Thermal Annealing of Graphene Oxide with Melamine Compounds (멜라민 화합물을 이용한 산화 그래핀 도핑 및 특성 평가)

  • Kim, Sumin;Kim, Hyun;Kim, So Yang;Han, Jong Hun
    • 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.

Properties of Gel-like Compounds Containing Flammable Solvents (Gel형 인화성 용제 Compound의 특성)

  • 강영구;김정훈
    • Journal of the Korean Society of Safety
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    • v.18 no.3
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    • pp.94-100
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    • 2003
  • Gel-like compounds containing flammable solvents were prepared to use fur cleaning agents in field of innovative industries and general purposes. And experiments were conducted to improve the defects of liquified flammable solvents from the view point of safety and health hazards. Flammable solvents used in this study were several single component flammable solvents(turpentine oil, N-methyl-2-pyrrolidone(NMP), d-limonene) and multi component flammable solvent(gasoline and ethanol). For gelation of flammable solvents, commercially Known as Aerosil(equation omitted) 200 fumed silica and triethanolamine(TEA) were used as gelation agent dispersant. The analyses on properties of gel-like compounds was studied by gelation and viscosity test pH test, volatility test and differential scanning calorimetry(DSC) measurement. The experimental results indicate that gel-like compounds containing flammable solvents have pH stability, high viscosity, volatile organic compounds(VOC) control by the decrease of volatility and odor component generation, fluidity control etc. From the experimental values, it can be predicted that the safety in the working place is improved by manufacturing flammable solvents into gel-like compounds.

TMA-Water Clathrate Compound of Cooling Characteristics for Low Temperature Latent Heat Storage (저온잠열축열을 위한 TMA-물계 포접화합물의 냉각특성)

  • Kim, Chang-Oh;Chung, Hyoun-Ho;Chung, Nak-Kyu
    • 한국태양에너지학회:학술대회논문집
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    • pp.296-301
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    • 2009
  • The ice storage system uses water for low temperature latent heat storage. However, a refrigerator capacity is increased and COP is decreased due to supercooling of water in the course of phase change from solid to liquid. This study investigates the cooling characteristics of the TMA-water clathrate compound including TMA (Tri-methyl-amine, $(CH_3)_3N)$ of $20{\sim}25wt%$ as a low temperature latent heat storage material. The results showed that the phase change temperature and the specific heat is increased and the supercooling degree is decreased as the weight concentration of TMA increased. Especially, the clathrate compound containing TMA 25wt% has the average phase change temperature of $5.8^{\circ}C$, the supercooling degree of $8.0^{\circ}C$ and the specific heat of 3.499 kJ/kgK in the cooling process. This can lead to reduction of operation time of refrigerator in low temperature latent heat storage system and efficiency improvement of refrigerator COP and overall system. Therefore, energy saving and improvement of utilization efficiency are expected.

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The Cooling Characteristics of Clathrate Compound according to Concentration of TMA

  • Lee, Jong-In;Kim, Chang-Oh;Chung, Nak-Kyu
    • International Journal of Air-Conditioning and Refrigeration
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    • v.17 no.1
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    • pp.32-36
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    • 2009
  • The ice storage system uses water for low temperature latent heat storage. However, a refrigerator capacity is increased and COP is decreased due to supercooling of water in the course of phase change from solid to liquid. This study investigates the cooling characteristics of the TMA-water clathrate compound including TMA (Tri-methyl-amine, $(CH_3)_3N$) of $20{\sim}25wt%$ as a low temperature latent heat storage material. The results showed that the phase change temperature and the specific heat is increased and the supercooling degree is decreased as the weight concentration of TMA increased. Especially, the clathrate compound containing TMA 25 wt% has the average phase change tempera ture of $5.8^{\circ}C$, the supercooling degree of $8.0^{\circ}C$ and the specific heat of 3.499 kJ/kgK in the cooling process. This can lead to reduction of operation time of refrigerator in low temperature latent heat storage system and efficiency improvement of refrigerator COP and overall system. Therefore, energy saving and improvement of utilization efficiency are expected.

Aroma-Active Compounds in Omandungi (Styela plicata)-Doenjang (Soybean Paste) Stew (오만둥이 된장찌개의 Aroma-active 화합물)

  • Jeong, Eun-Jeong;Cho, Woo-Jin;Cha, Yong-Jun
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.41 no.6
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    • pp.414-418
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    • 2008
  • Volatile compounds in Omangdungi (Styela plicata)-Doenjang (soybean paste) stew were analyzed using solvent-assisted flavor evaporation/gas chromatography/mass-selective detection/olfactometry (SAFE/GC/MSD/O) and aroma extract dilution analysis (AEDA). The GC/O analysis detected 37 volatile compounds, of which 32 were positively identified, and included 9 aldehydes, 5 alcohols, 4 aromatic hydrocarbons, 4 ketones, 3 esters, 3 N-containing compounds, 2 acids, 1 S-containing compound, and 1 furan. Nine aroma-active odorants ($\log_3FD{\geq}3.0$) in the sample included six compounds derived from Doenjang (3-methyl(thio)propanal, tetramethylpyrazine, 4-vinyl-2-methoxyphenol, 2-acetylpyrrole, butyric acid, and 2-methoxyphenol) and three compounds from Omangdungi (2-acetyl-2-thiazoline, 9-decanol, and 6-decenol). Three compounds derived from Omangdungi (9-decanol, 6-decenol, and 6-nonenol) were thought to enhance the seafood-like flavor of Omangdungi-Doenjang stew.

Immobilization and Characterization of a Liposome-Mediated Reconstituted Nicotinic Acetylcholine Receptor

  • Suh, Jeong-Ihn;Palk, Bo-Hyun;Oh, Se-Zu;Suh, Jung-Hun;Cho, Key-Seung;Palk, Young-Ki
    • BMB Reports
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    • v.28 no.2
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    • pp.155-161
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    • 1995
  • A nicotinic acetylcholine receptor (nAchR) isolated from the electric tissues of Torpedo californica has been reconstituted into a vesicle comprising a bifunctional azo-ligand (Bae 1) compound, and a liposome containing phospholipids and cholesterol (1 : 1, w/w). The liposome-mediated reconstituted receptor showed a concentration-dependent response to cholinergic drugs in a lithium ion flux assay. This liposome-mediated reconstituted nAchR was immobilized onto an electrode using various synthetic polymers which were tested for their response to the cholinergic ligands. The immobilized nAchR not only exhibited a linear response to a wide range of cholinergic ligand concentrations but also retained an operational stability which lasted for longer than 6 days. Thus, this result provides a basis for application of the immobilized nAchR-based biosensor in detecting cholinergic ligands in vitro.

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Effect of top dressing of Compound Fertilizer Containing nitrate (Ammonium Nitrate Sulfate) on Paddy Rice (수도용(水稻用) 질산태질소함유(窒酸態窒素含有) 복합비료(複合肥料)의 추비효과(追肥效果))

  • Kim, Jeong-Je;Jang, Yong-Seon;Cho, Byong-Ok;Huh, Beom-Lyang
    • Korean Journal of Soil Science and Fertilizer
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    • v.21 no.3
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    • pp.289-295
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    • 1988
  • An ordinary paddy variety Hwaseong and a high-yielding variety Samgang were taken under investigation to test the effect of top dressing of newly formulated three compound fertilizers on rice plants for at sprouting heads. The fertilizer formulate used were C. F. I (14-0-14; $NO_3-N$ and $NH_4-N$) and C. F. II (14-0-14; $NH_4-N$ only) and C. F. III (14-0-14 + OM 10%; $NO_3-N$ and $NH_4-N$). A field experiment was conducted on a plot of Gyuam series. The following results were obtained: 1. Effects of compound fertilizers at sprouting heads a. Hwaseong variety exhibited 5-10% yielding increases on the plots with application of 2nd compound fertilizer (I) and (II) compared to straight fertilizer of (I) and (III). Fertilization with 2nd and 3rd compound fertilizers gave the best result when they are done 15 days before heading. A yield increase of 3-5% was achieved when the fertilization was done 20 days before heading in the case of Samgang variety, but no beneficial effect was observed with an application 10 days before heading. b. Rate of barren grains was at the minimum in the compound fertilizer (II) plots of both Hwaseong and Samgang varieties. c. Content of $NO_3-N$ in soils and grain yield appeared to be positively correlated($r=0.618^*$) 2. Effects of heading fertilizers on artificially reduced conditions of soil a. No significant difference in Eh values were measured among reduced paddy soils. The compound fertilizer of (II) presented the best result in yield increases regardless of rice variety. b. Rate of barren grains in both varieties was observed at the minimum on the application of compound fertilizer of (II). c. No great difference of mineral contents was detected among plants from different treatments.

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Synthesis, chemically and electrochemically polymerization of N-substituted pyrrole containing azo chromophore and its copolymerization with pyrrole

  • Hosseini, Seyed Hossein
    • Advances in materials Research
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    • v.1 no.4
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    • pp.299-310
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    • 2012
  • This article describes the synthesis of a novel N-substituted pyrrole monomer containing an azobenzene group. The 2-[N-ethyl-N-[4-[(4-nitrophenyl) azo]-phenyl] amino] ethyl-3-chloropropionate (RedII) compound was synthesized via reaction of 4-nitro-4'-[N-ethyl-N-(2-hydroxyethyl)-amino] azobenzene (RedI) and 3-chloropropionic acid. RedII was reacted with the potassium salt of pyrrole then 2-[N-ethyl-N-[4-[(nitro phenyl) azo] phenyl] amino] ethyl-N-pyrrolyl propionate (Py-RedII) was prepared. Chemical polymerization of Py-RedII and copolymerization of Py-RedII with pyrrole carried out using $FeCl_3$. Poly (2-[N-ethyl-N-[4-[(nitro phenyl) azo] phenyl] amino] ethyl-N-pyrrolyl propionate) (PPy-RedII) was characterized by UV, IR, $^1HNMR$, $^{13}CNMR$ spectroscopies. Electropolymerization of Py-RedII and electroco-polymerization of Py-RedII and pyrrole were studied using conventional three electrodes system, Ag/AgCl reference electrode, platinum counter electrode and GC disk working electrode. Scanning electron microscopy (SEM), thermogravimetry analysis (TGA) and differential scanning calorimetry (DSC) were used for thermal and rheological studies. The TGA curve of PPy-RedII demonstrated a high thermal stability up to 200°C and its DSC thermogram showed two endothermic peaks at 88 and $122^{\circ}C$. The glass transition temperature of the polymer was found to be above the room temperature. Electrical conductivities of PPy-RedII and it's copolymer with pyrrole (PPy-RedII-co-Py) were studied by the four-probe method and produced conductivities of $7.5{\times}10^{-4}$ and $6.5{\times}10^{-3}Scm^{-1}$, respectively.

Environmental toxicity and biodegradation of Pseudomonas sp. EL-G527 producing biosurfactant

  • Mi Seon, Cha;Hong Ju, Son;Sang Jun, Lee
    • Proceedings of the Korean Environmental Sciences Society Conference
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    • pp.452-454
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    • 2002
  • A biosurfactant-producing microorganism, .Pseudomouos sp. EL-G527 was isolated from activated sludge by enrichment culture when grown on mineral salt medium containing n-hexadecane as a carbon source. The biosurfactant from .Pseudomonar sp. EL-G527 exhibited lesser toxicity to bacterial population than synthetic surfactants and in the biodegradation test, biosurfactant was rapidly degraded and lost its activity as surface active material after 1 day incubation. In this study, the biosurfactant from Pseudomonas sp. EL-G527 was effective surface-active compound, more biodegradable and less toxic to microbial ecosystem than various synthetic surfactants.

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A Study on Cooling Characteristics of Clathrate Compound with Concentration of TMA (TMA 농도에 따른 포접화합물의 냉각특성에 대한 연구)

  • Kim Jin-Heung;Chung Nak-Kyu;Kim Chang-Oh
    • Journal of Energy Engineering
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    • v.14 no.1
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    • pp.18-23
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    • 2005
  • This study is investigated the cooling characteristics of the TMA clathrate compound including TMA (Tri-methyl-amine, (CH₃)₃N) of 20~25 wt% as a low temperature storage material at -5℃ heat source. The results showed that as the concentration of TMA is increased, phase change temperature and specific heat are increased, but the supercooling and retention time of liquid phase are decreased. Especially, low temperature storage material containing TMA 25 wt% has the average of phase change temperature of 5.8℃, supercooling of 8.0℃, retention time of liquid phase for 10 minutes and specific heat of 4.099 kJ/kg℃ in the cooling process. From the results of this study, TMA clathrate compound showed higher phase change temperature than water md supercooling repression effect.