• Bulletin of the Korean Chemical Society
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• 제18권8호
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• pp.850-856
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• 1997

A series of tetradentate Schiff-base ligands; 1,3-bis(salicylideneimino) propane, 1,4-bis(salicylideneimino)butane, and 1,5-bis(salicylideneimino)pentane, and their Cu(Ⅱ) and Ni(Ⅱ) complexes have been synthesized. The properties of ligands and complexes have been characterized by elemental analysis, IR, NMR, UV-Vis spectra, molar conductance, and thermogravimetric anaylsis. The mole ratio of Schiff base to metal at complexes was found to be 1 : 1. All complexes were four-coordinated configuration and non-ionic compound. The electrochemical redox processes of the ligands and their complexes in DMF solution containing 0.1 M TEAP as supporting electrolyte have been investigated by cyclic voltammetry, chronoamperometry, differential pulse voltammetry at glassy carbon electrode, and by controlled potential coulometry at platinum gauze electrode. The redox process of the ligands was highly irreversible, whereas redox process of Cu(Ⅱ) and Ni(Ⅱ) complexes was observed as one electron transfer process of quasi-reversible and diffusion-controlled reaction. Also the electrochemical redox potentials of complexes were affected by chelate ring size of ligands. The diffusion coefficients of Cu(Ⅱ) and Ni(Ⅱ) complexes in DMF solution were determined to be 4.2-6.6×10-6 cm2/sec. Also the exchange rate constants were determined to be 3.6-9.7×10-2 cm/sec.

• Journal of Microbiology and Biotechnology
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• 제29권9호
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• pp.1424-1433
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• 2019

DDT is a hydrophobic organic pollutant, which can be bio-accumulated in nature and have adverse consequences on the physical condition of humans and animals. This study investigated the relationship between the white-rot fungus Pleurotus eryngii and biosurfactant-producing bacterium Ralstonia pickettii associated with the degradation of DDT. The effects of R. pickettii on fungal development were examined using in vitro confrontation assay on a potato dextrose agar (PDA) medium. R. pickettii culture was added to the P. eryngii culture at 1, 3, 5, 7, and 10 ml ($1ml{\approx}1.44{\times}10^{13}CFU$). After 7 d incubation, about 43% of the initial DDT ($12.5{\mu}M$) was degraded by the P. eryngii culture only. The augmentation of 7 ml of R. pickettii culture revealed a more highly optimized synergism with DDT degradation being approximately 78% and the ratio of optimization 1.06. According to the confrontational assay, R. pickettii promoted the growth of P. eryngii towards the bacterial colony, with no direct contact between the bacterial cells and mycelium (0.71 cm/day). DDD (1,1-dichloro-2,2-bis(4-chlorophenyl) ethane), DDE (1,1-dichloro-2,2-bis(4-chlorophenyl) ethylene), and DDMU (1-chloro-2,2-bis(4-chlorophenyl) ethylene) were identified as metabolic products, indicating that the R. pickettii could enhance the DDT biodegradation by P. eryngii.

• 한국식품과학회지
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• 제35권3호
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• pp.399-404
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• 2003

본 논문에서는 adipic acid(AA)와 1,4-butane diol(BD)을 반응 기질로 이용한 에스테르화 반응에 의하여 bis(4-hydroxy butyl) adipate(BHBA)를 생산하고자 하였으며, 이때 AA와 BD의 몰비율, 촉매(TBT)농도 및 반응온도 등이 에스테르화 반응에 미치는 영향을 검토함으로써 BHBA를 효율적으로 생산하기 위한 기초 최적화 조건을 제시하고자 하였다. AA와 BD 사이의 직접적 에스테르화 반응시 몰비율이 2.0 이상일 때, 반응속도를 살펴본 결과 몰비율([AA]/[BD])이 증가함에 따라 반응속도는 감소함을 확인하였으며, 촉매농도에 따른 반응속도를 살펴보았을 때 촉매농도가 증가할수록 반응속도상수가 증가함을 알 수 있었다. 또한, 반응온도가 증가함에 따라 반응속도상수는 무촉매와 촉매사용시 모두 증가하였으며, 무촉매 반응 및 촉매사용 반응시의 활성화에너지는 각각 198.5 kJ/mol 및 94.8 kJ/mol로서 TBT 촉매사용시 반응이 약 2배 정도 수월해짐을 알 수 있었다.

• 멤브레인
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• 제14권1호
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• pp.26-36
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• 2004

상전환 방법으로 제조된 음이온 성 Poly(his[4-(3-aminophenoxy)phenyl]sulfone pyromellite)imide(ACPI) 한외여과막의 순수 투과유속과 용질 배재도 측정치로 투과성능을 연구하였다. ACPI 한외여과막의 투과성능은 캐스팅 용액의 조성과 막 제조 및 측정조건에 영향을 받았다. Bovine serum albumin (BSA) 용액을 pH 2.5-9.0 상태에서 ACPI 한외여과 막의 상대투과유속과 membrane filtration index (MFI) 측정한 결과 BSA의 등전점에서 멀어 질수록 상대투과유속은 증가하고 막 오염정도를 나타내는 MFI는 감소하였다. 또한, 친수성인 ACPI 한외여과막의 이온교환용량(IEC)이 증가할수록 상대투과유속은 증가하고, MFI는 감소하였다.

• Nuclear Engineering and Technology
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• 제56권7호
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• pp.2595-2609
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• 2024

This paper introduces a base isolation system-tuned mass damper inerter (BIS-TMDI) hybrid system to the AP1000 nuclear power plant (NPP), which reduces seismic damage potential of the NPP structure. The effects of fluid-structure interaction (FSI) caused by the passive containment cooling system water storage tank (PCCWST) on NPP's seismic performance are investigated. The FSI of water tank theoretical model is considered based on the Housner's model, and a series of time history analyses are performed to prove the rationality of the proposed model. Three single-objective optimization strategies are employed to minimize the relative displacement variance and absolute acceleration variance of the upper structure, as well as the filtered energy index (FEI). Furthermore, a multi-objective optimization strategy considering all these three indexes is proposed to obtain optimal parameters of vibration control. The influence of vibration control strategies on the relative deformation and acceleration of the upper structure is explored with various water level ratios. The analytical results indicate that the proposed BIS-TMDI strategy has significantly reduced the NPP structure's seismic response. The effectiveness of the vibration control strategy is influenced by the water level ratio, emphasizing the significance of designing an appropriate water level ratio to reduce NPP structure's seismic response.

• 경제분석
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• 제27권3호
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• pp.1-32
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• 2021

본 연구는 통화정책 전달경로 중 은행자본경로와 위험추구경로가 국내은행에도 작동하는지에 대해 실증분석하였다. 이를 위해 확장적 통화정책이 은행의 예대금리차, BIS비율, 위험가중자산비율 및 대출 등에 미치는 영향을 분석하였다. 실증분석은 기존 연구에서 통화정책 영향분석에 많이 사용된 Uhlig (2005)의 부호제약 SVAR(Structural VAR) 모형을 토대로 실시하였다. 본 연구는 실증분석을 통해 국내외 기존 연구 결과와 유사하게 국내은행에서도 은행자본경로 및 위험추구경로가 작동하는 것을 확인하였다. 확장적 통화충격에 대해 국내은행의 예대금리차는 확대되었으며, 자기자본비율은 개선되었고, 이후 총대출이 증가하는 것으로 분석되었다. 이는 은행자본경로가 작동함을 의미한다. 또한, 실질콜금리에 대한 확장적 통화충격에 대해 위험가중자산비율이 증가하는 것으로 분석되었다. 이는 위험추구경로가 작동함을 의미한다. 본 연구의 시사점은 다음과 같다. 확장적 통화정책 지속 시 은행자본경로 작동으로 단기적으로 은행 건전성과 수익성이 개선되는 효과도 있으나, 위험추구경로 작동으로 중장기적으로 은행의 위험추구(risk-taking) 행위가 심화되어 은행의 실질적 건전성에 악영향을 줄 수 있다. 이에 따라 금융당국은 확장적 통화정책 지속 시 편중리스크 발생 및 시스템리스크 증가 등에 대한 선제적인 모니터링 및 감독을 강화할 필요가 있다.

• Bulletin of the Korean Chemical Society
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• 제20권4호
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• pp.422-426
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• 1999

The Grignard reactions of bis(chloromethyl)dimethylsilane (1) with trimethylchlorosilane (2) in THF give both the intermolecular C-Si coupling and intramolecular C-C coupling products. At beginning stage, 1 reacts with Mg to give the mono-Grignard reagent ClCH2Me2SiCH2MgCl (1) which undergoes the C-Si coupling reaction to give MC2Si(CH2SiMe3)2 3, or C-C coupling to a mixture of formula Me3SiCH2(SiMe2CH2CH2)nR1 (n = 1, 2, 3, ..; 4a, R1I = H: 4b, R1 = SiMe3). In the reaction, two reaction pathways are involved: a) Ⅰ reacts with 2 to give Me3SiCH2SiMe2CH2Cl 6 which further reacts with Mg to afford a Me2SiCH2Mel-SiCH2MgCl (Ⅱ) or b) I cyclizes intramolecularly to a silacyclopropane intermediate A, which undergoes a ring-opening polymerization by the nucleophilic attack of the intermediates I or Ⅱ, followed by the termination reaction with H2O and 2, to give 4a and 4b, respectively. As the mole ratio of 2/1 increased from 2 to 16 folds, the formation of product 3 increased from 16% to 47% while the formation of polymeric products 4 was reduced from 60% to 40%. The intermolecular C-Si coupling reaction of the pathway a becomes more favorable than the intramolecular C-C coupling reaction of the pathways b at the higher mole ratio of 2/1.

• 반도체디스플레이기술학회지
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• 제8권4호
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• pp.15-19
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• 2009

A high efficient organic red light emitting device with structure of DNTPD/TAPC/$Bebq_2$ :[$(pq)_2Ir(acac)$, SFC-411]/SFC-137 was fabricated on the plastic substrate, which can be applied in the fields of flexible display and illumination. In the device structure, N,N'-diphenyl-N,N'-bis-[4-(phenyl-m-tolylamino)-phenyl]-biphenyl-4,4'-diamine[DNTPD] as a hole injection layer and 1,1-bis-(di-4-tolylaminophenyl) cyclohexane [TAPC] as a hole transport were used. Bis(10-hydroxybenzo[h]quinolinato) beryllium complex [$Bebq_2$] was used as a light emitting host material. The host material, $Bebq_2$ was doubly doped with volume ratio of 7% iridium(III)bis-(2-phenylquinoline)acetylacetonate[$(pq)_2$Ir(acac)] and 3% SFC-411[red phosphor dye coded by the proprietary company]. And then, SFC-137 was used as an electron transport layer. The luminous intensity and current efficiency of the fabricated device were $22,780\;cd/m^2$ at 9V and 17.3 cd/A under $10,000\;cd/m^2$, respectively. The maximum current efficiency of the device was 22.4cd/A under $580\;cd/m^2$.

• 대한화학회지
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• 제45권5호
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• pp.429-435
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• 2001

단량체인 N,N'-bis(2-pyrrol-1-yl-propyl)-4,4'-bipyridine(bpb)을 유리탄소전극 상에 전기화학적으로 중합한 고분자 피막전극을 erichrome black T(EBT) 와 glutathione(GSSG)의 1:1 용액으로 수식하여 GC/poly-bpb, EBT, GSSG형의 전극을 제작하고 이로써 Zn(II)을 포집한 전극을 제작하였다. 수식된 피막 내에서 이온의 확산계수는 아연이온이 포집되기 전후에 각각 2.43${\times}10^{-15}$과 9.14${\times}10^{-15}cm^2s^{-1}$으로 피막내의 전기화학적 활성자리에서 이탈이 거의 일어나지 않는 안정한 전극이다. 중합된 bpb의 양이 2.83${\times}10^4gmol^{-1}$에 대하여 1.17${\times}10^4gmol^{-1}$의 아연이온이 포집되었다. 이들 중에 산화-환원 과정에서 회합/해리에 관여하는 이온은 포집된 180개의 이온들 중에서 81.7%였다. 이는 EBT 만으로 수식된 전극에서 보다 3배정도 큰 값이다.

• Journal of Microbiology and Biotechnology
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• 제27권7호
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• pp.1306-1315
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• 2017

DDT (1,1,1-trichloro-2,2-bis(4-chlorophenyl) ethane) is one of the organic synthetic pesticides that has many negative effects for human health and the environment. The purpose of this study was to investigate the synergistic effect of mixed cutures of white-rot fungus, Pleurotus ostreatus, and biosurfactant-producing bacteria, Pseudomonas aeruginosa and Bacillus subtilis, on DDT biodegradation. Bacteria were added into the P. ostreatus culture (mycelial wet weight on average by 8.53 g) in concentrations of 1, 3, 5, and 10 ml ($1ml{\approx}1.25{\times}10^9$ bacteria cells/ml culture). DDT was degraded to approximately 19% by P. ostreatus during the 7-day incubation period. The principal result of this study was that the addition of 3 ml of P. aeruginosa into P. ostreatus culture gave the highest DDT degradation rate (approximately 86%) during the 7-day incubation period. This mixed culture combination of the fungus and bacteria also gave the best ratio of optimization of 1.91. DDD (1,1-dichloro-2,2-bis(4-chlorophenyl) ethane), DDE (1,1-dichloro-2,2-bis(4-chlorophenyl) ethylene), and DDMU (1-chloro-2,2-bis(4-chlorophenyl) ethylene) were detected as metabolic products from the DDT degradation by P. ostreatus and P. aeruginosa. The results of this study indicate that P. aeruginosa has a synergistic relationship with P. ostreatus and can be used to optimize the degradation of DDT by P. ostreatus.