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Woojin Go(고우진),Dongyoung Lee(이동영),Yongwon Seo(서용원) 한국신재생에너지학회 2021 한국신재생에너지학회 학술대회논문집 Vol.2021 No.7
In gas and oil transportation, the formation of gas hydrates can cause pipeline plugging, which might lead to severe industrial disasters or environmental accidents. Injection of hydrate inhibitors is one of the well-known methods to avoid hydrate formation in the transmission pipelines. However, traditional hydrate inhibitors like methanol and ethylene glycols require vast amounts for the effective control of gas hydrates. On the other hand, low dosage hydrate inhibitors (LDHIs) have been investigated by many researchers since they require a much smaller amount to retard or delay the nucleation and growth of gas hydrates. Therefore, a discovery of new potential LDHIs and their performance evaluation for gas hydrate avoidance is very important in related fields. In this work, three monomeric organic substances of urea, acetamide, and glycine were suggested as effective LDHIs. Both a HP-autoclave and a HP µ-DSC were utilized to assess their inhibition performance on the CH<sub>4</sub> hydrate formation. For further estimation, two computational approaches of COSMO-RS and QTAIM were deployed. All three substances showed the inhibition and synergistic effects on CH<sub>4</sub> hydrate formation. Bond critical points, σ -profile, and σ -potential analyses well supported the experimental results. In conclusion, experimental and computational approaches in this work suggest the milestone to find effective biodegradable gas hydrate inhibitors.
Lee, Dongyoung,Go, Woojin,Seo, Yongwon Pergamon Press 2019 Energy Vol.182 No.-
<P><B>Abstract</B></P> <P>Amino acids (glycine and alanine) and ionic liquids ([BMIM][BF<SUB>4</SUB>] and [BMIM][I]) were examined for their inhibition effects on CH<SUB>4</SUB> hydrates with experimental and computational approaches. Both amino acids and ionic liquids functioned well as thermodynamic hydrate inhibitors, by shifting equilibrium curves of CH<SUB>4</SUB> hydrates toward harsh conditions. However, powder X-ray diffraction patterns indicated that amino acids and ionic liquids did not affect the hydrate structure because they were not included in the hydrate cages due to their large molecular size. Gas uptake measurements showed that the conversion of water into gas hydrates and the formation rates of CH<SUB>4</SUB> hydrate were significantly influenced by inhibitors. Density functional theory calculations indicated that [BMIM][BF<SUB>4</SUB>] had a larger potential than glycine to inhibit gas hydrate formation by giving a more negative interaction energy between a cage and an inhibitor molecule. The time-dependent Raman spectra collected during CH<SUB>4</SUB> hydrate formation demonstrated that [BMIM][BF<SUB>4</SUB>] hindered CH<SUB>4</SUB> molecules from occupying small (5<SUP>12</SUP>) cages, whereas glycine had a strong influence on large (5<SUP>12</SUP>6<SUP>2</SUP>) cages of sI hydrates. The experimental and computational results provide a better understanding of inhibition mechanisms of gas hydrates and thus can contribute to the improved control of hydrate formation in oil and gas pipelines.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We examine CH<SUB>4</SUB> hydrates in the presence of inhibitors for hydrate control. </LI> <LI> We use amino acids and ionic liquids to examine inhibition mechanisms. </LI> <LI> Inhibitors do not affect the structure of CH<SUB>4</SUB> hydrate. </LI> <LI> Glycine and [BMIM][BF<SUB>4</SUB>] inhibit large 5<SUP>12</SUP>6<SUP>2</SUP> cages and small 5<SUP>12</SUP> cages, respectively. </LI> </UL> </P>
Lee, Ji Hwan,Go, Donghyun,Kim, Woojin,Lee, Giseog,Bae, Hyojeong,Quan, Fu Shi,Kim, Sun Kwang The Korean Society of Pharmacology 2016 The Korean Journal of Physiology & Pharmacology Vol.20 No.4
This study was performed to investigate whether the spinal cholinergic and serotonergic analgesic systems mediate the relieving effect of electroacupuncture (EA) on oxaliplatin-induced neuropathic cold allodynia in rats. The cold allodynia induced by an oxaliplatin injection (6 mg/kg, i.p.) was evaluated by immersing the rat's tail into cold water ($4^{\circ}C$) and measuring the withdrawal latency. EA stimulation (2 Hz, 0.3-ms pulse duration, 0.2~0.3 mA) at the acupoint ST36, GV3, or LI11 all showed a significant anti-allodynic effect, which was stronger at ST36. The analgesic effect of EA at ST36 was blocked by intraperitoneal injection of muscarinic acetylcholine receptor antagonist (atropine, 1 mg/kg), but not by nicotinic (mecamylamine, 2 mg/kg) receptor antagonist. Furthermore, intrathecal administration of $M_2$ (methoctramine, $10{\mu}g$) and $M_3$ (4-DAMP, $10{\mu}g$) receptor antagonist, but not $M_1$ (pirenzepine, $10{\mu}g$) receptor antagonist, blocked the effect. Also, spinal administration of $5-HT_3$ (MDL-72222, $12{\mu}g$) receptor antagonist, but not $5-HT_{1A}$ (NAN-190, $15{\mu}g$) or $5-HT_{2A}$ (ketanserin, $30{\mu}g$) receptor antagonist, prevented the anti-allodynic effect of EA. These results suggest that EA may have a significant analgesic action against oxaliplatin-induced neuropathic pain, which is mediated by spinal cholinergic ($M_2$, $M_3$) and serotonergic ($5-HT_3$) receptors.
Hydrophilic and Hydrophobic Ionic Liquids as Gas Hydrate Inhibitors
Soyeong Yun(윤소영),Dongyoung Lee(이동영),Woojin Go(고우진),Ki-Sub Kim(김기섭),Yongwon Seo(서용원) 한국신재생에너지학회 2021 한국신재생에너지학회 학술대회논문집 Vol.2021 No.7
Gas hydrate inhibitors have been generally used to avoid pipeline plugging risks cause by gas hydrate formation in gas and oil field operations. Ionic liquids (ILs) can act as both a thermodynamic hydrate inhibitor (THI) and a kinetic hydrate inhibitor (KHI) and therefore, they are called ‘dual’ function inhibitors. In this study, we focused on the hydrophobicity of ILs and examined the inhibition effect of ILs on the kinetics and thermodynamic stability of CH<sub>4</sub> hydrate by measuring the onset temperature (Tonset) and hydrate phase equilibria. Total 8 ionic pairs (2 cations ([EMIM]+ and [BMIM]+) � 4 anions ([CI]-, [BF<sub>4</sub>]-, [PF<sub>6</sub>]-, and [Tf<sub>2</sub>N]-)), which have the following hydrophobicity order : [EMIM]+ 〈[BMIM]+ for cation and [CI]- 〈[BF<sub>4</sub>]- 〈[PF<sub>6</sub>]- 〈[Tf<sub>2</sub>N]- for anion, were investigated. Moreover, molecular dynamics (MD) simulations were used to figure out the molecular behaviors of ILs for hydrate inhibition by examining radial distribution function (RDF), density profile, and order parameter analysis. Hydrogen bonding ability of anions with water molecules and cage adsorption of cations were found to be the major pathways of preventing and retarding the formation and growth of CH<sub>4</sub> hydrate. Our research will provide a better understanding of the inhibition mechanism of various hydrophilic and hydrophobic ILs on CH<sub>4</sub> hydrate formation.
정재묵 ( Jaemook Jeong ),유준택 ( Joontaek Yoo ),김희용 ( Heeyong Kim ),이선길 ( Sunkil Lee ),고우진 ( Woojin Go ),김영혜 ( Yeonghye Kim ) 한국수산과학회(구 한국수산학회) 2015 한국수산과학회지 Vol.48 No.5
Species composition of the fish in the coastal waters of Jindo was determined using monthly sample collection by a gape net with wings in 2014. Of a total of 41 fishes collected, the dominant species were Engraulis japonicus, Thryssa kammalensis, Sardinella zunasi, Leiognathus nuchalis, Amblychaeturichthys hexanema, Neosalanx anderssoni, Acanthogobius flavimanus. The former three species were the migratory species and the other four species were the resident species. These 7 fishes accounted for 99.6% of the total number of individuals collected. Monthly species composition did not show a clear seasonal trend. The peak number of individuals occurred in May, lowest in November. Fish were divided into four groups by the cluster analysis.