• 한국환경과학회지
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• 제19권5호
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• pp.565-575
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• 2010

This study is mainly focused on micellar effect of cetylpyridinium chloride(CPyCl) solution including alkylbenzimidazole(R-BI) on dephosphorylation of diphenyl-4-nitrophenylphosphinate(DPNPIN) in carbonate buffer(pH 10.7). The reactions of DPNPIN with R-BI$^{\ominus}$ are strongly catalyzed by the micelles of CPyCl. Dephosphorylation of DPNPIN is accelerated by BI$^{\ominus}$ ion in $10^{-2}M$ carbonate buffer(pH 10.7) of $4{\times}10^{-3}M$ CPyCl solution up to 100 times as compared with the reaction in carbonate buffer by no BI solution of $4{\times}10^{-3}M$ CPyCl. The value of pseudo first order rate constant($k^m_{BI}$) of the reaction in CPyCl solution reached a maximum rate constant increasing micelle concentration. Such rate maxima are typical of micellar catalyzed bimolecular reactions. The reaction mediated by R-BI$^{\ominus}$ in micellar solutions are obviously slower than those by BI$^{\ominus}$, and the reaction rate were decreased with increase of lengths of alkyl groups. It seems due to steric effect of alkyl groups of R-BI$^{\ominus}$ in Stern layer of micellar solution. The surfactant reagent, cetylpyridinium chloride(CPyCl), strongly catalyzes the reaction of diphenyl-4-nitrophenylphosphinate(DPNPIN) with alkylbenzimidazole (R-BI) and its anion(R-BI$^{\ominus}$) in carbonate buffer(pH 10.7). For example, $4{\times}10^{-3}M$ CPyCl in $1{\times}10^{-4}M$ BI solution increase the rate constant ($k_{\Psi}=1.0{\times}10^{-2}sec^{-1}$) of the dephosphorylation by a factor ca.14, when compared with reaction ($k_{\Psi}=7.3{\times}10^{-4}sec^{-1}$) in $1{\times}10^{-4}M$ BI solution(without CPyCl). And no CPyCl solution, in $1{\times}10^{-4}M$ BI solution increase the rate constant ($k_{\Psi}=7.3{\times}10^{-4}sec^{-1}$) of the dephosphorylation by a factor ca.36, when compared with reaction ($k_{\Psi}=2.0{\times}10^{-5}sec^{-1}$) in water solution(without BI). This predicts that the reactivities of R-BI$^{\ominus}$ in the micellar pseudophase are much smaller than that of BI$^{\ominus}$. Due to the hydrophobicity and steric effect of alkyl group substituents, these groups would penetrate into the core of the micelle for stabilization by van der Waals interaction with long alkyl groups of CPyCl.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2001년도 정기총회 및 학술대회
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• pp.199-202
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• 2001

ISO/IEC 15938-1(MPEG-7 Systems)에서는 멀티미디어 컨텐츠에 대한 메타데이터의 효율적인 전송과 저장을 위한 이진 표현 방법인 BiM(binary format for MPEC-7)을 제공한다. 멀티미디어 컨텐츠를 기술(description)하는 메타데이터의 텍스트 표현은 대체로 많은 저장 용량과 전송 리소스를 요구하기 때문에 효율적인 압축을 위해서는 이진 형식으로의 변환이 요구된다. 또한 텍스트 형식은 방송 환경과 같은 스트리밍 전송에는 적절하지 못한 단점이 있다. BiM은 컨텐츠에 대한 기술을 전체 또는 2개 이상의 AU(access units) 단위로 분할하며 부호화하는 방법을 지원함으로써 스트리밍 전송을 가능하게 한다. 이러한 구조는 이진 포맷 형태로 표현되는 헤더를 가지는 패킷 기반 형태이며, 융통성이 있는 전송 순서를 제공한다. 또한, 비트 스트림의 전체를 해석(parsing)하지 않고 랜덤 엑세스 기능을 제공하는 장점이 있다. BiM이 지닌 이러한 장점들로 인하여 현재 방송산업계를 중심으로 메타데이터를 방송에 활용하기 위한 기술을 표준화하는 국제 민간 표준화 기구인 TV-Anytime 포럼에서는 방송 컨텐츠에 대한 메타데이터의 압축에 관한 요구사항을 만족하는 하나의 방법으로 BiM을 고려하고 있다 본 논문에서는 이러한 MPEG-7 시스템의 BiM을 소개하고, 이를 이용하여 TV-Anytime 포럼의 메타데이터를 이진 포맷으로 부호화한 실험과 그 결과를 기술한다.

• 마이크로전자및패키징학회지
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• 제10권2호
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• pp.61-67
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• 2003

고집적 플립 칩 기술을 위한 $50{\mu}m$ 직경의 극미세 58Bi-42Sn 솔더 범프와 Au/Ni/Ti UBM의 계면 반응에 따른 금속간 화합물을 분석하였다. 증발증착법과 lift-off 방법으로 극미세 Bi-Sn 솔더 범프를 형성하고 급속열처리 장비를 이용하여 리플로 공정을 실시하였다. 리플로 공정에서의 냉각속도를 변화시키면서 제작한 솔더 범프의 표면과 단면을 주사전자현미경으로 관찰하였다 $Au(0.1{\mu}m)$/Ni/Ti UBM 위의 극미세 58Bi-42Sn 솔더 범프의 표면과 내부에서 facet 특성을 갖는 다각형의 금속간 화합물들이 다수 관찰되었다. 주사전자현미경의 EDS 분석과 X-선 회절분석으로 확인한 결과 이 금속간 화합물은 $(Au_xBi_yNi_{1-x-y})Sn_2$상임을 확인하였다.

• ETRI Journal
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• 제30권1호
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• pp.161-163
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• 2008

An M-ary bi-orthogonal modulation scheme for ultra-wideband (UWB) systems capable of narrowband interference (NBI) suppression is proposed in this letter. We utilize a set of bi-orthogonal pulse series to achieve NBI suppression. Through analysis and simulation, we verify that the proposed scheme can suppress NBIs effectively.

• 약학회지
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• 제37권1호
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• pp.95-99
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• 1993

Peroxidase activity of cytochrome P-450 was examined using N, N-dimethylaniline (NDA) as a substrate and cumene hydroperoxide (CHP) as an oxidant. The initial rates of the N-demethylation for varied concentrations of NDA (0.05-0.5 mM) by P-450 at different fixed concentrations of CHP (0.02-0.2 mM) were determined. The results suggest that P-450 proceeds its peroxidative reaction by the rapid equilibrium random bi bi mechanism to form a ternary complex with substrate and oxidant as an active intermediate.

• 미생물학회지
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• 제32권1호
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• pp.91-95
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• 1994

토양에서 분리된 Enterobacter agglomerans CBNU45는 type II 제한효소인 EagBI을 생산하고 있음을 발견하였다. EagBI을 DEAE-cellulose, phosphocellulose P11, hydroxylapatite column chromatography를 거쳐 부분 정제하여 그 특성을 알아보았다. EagBI은 여섯개의 염기배열 5’-CGAT${\downarrow}$CG-3’을 인식하고 T 와 C 사이를 절단하여 두개의 염기가 3’-말단쪽으로 돌출된 cohesive end를 형성하였다. EagBI의 반응 최적조건은 10mM Tris-HCl(pH 7.8), 6~10mM $MgCl_2$, 37${\circ}C$이었으며 NaCl이 없는 반응 완충용액에서 가장 좋은 활성을 보였다. EagBI은 $dam^-$와 $dam^+$ 메칠화 DNA도 절단할 수 있으며 65${\circ}C$에서 10분 동안 열처리하였을 때 효소의 활성을 상실하였다. 따라서 EagBI은 PvuI의 isoschizomer이나 NaCl 요구성과 열안정성에서 PvuI보다 편리한 제한효소로 확인되었다.

• 한국환경과학회지
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• 제21권5호
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• pp.585-596
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• 2012

This study is mainly focused on micellar effect of cetyltrimethyl ammonium bromide(CTABr) solution including alkylbenzimidazole(R-BI) on dephosphorylation of isopropyl-4-nitrophenylphosphinate(IPNPIN) in carbonate buffer(pH 10.7). The reactions of IPNPIN with R-$BI^{\ominus}$ are strongly catalyzed by the micelles of CTABr. Dephosphorylation of IPNPIN is accelerated by $BI^{\ominus}$ ion in $10^{-2}$ M carbonate buffer(pH 10.7) of $4{\times}10^{-3}$ M CTABr solution up to 89 times as compared with the reaction in carbonate buffer by no benzimidazole(BI) solution of $4{\times}10^{-3}$ M CTABr. The value of pseudo first order rate constant($k_{\Psi}$) of the reaction in CTABr solution reached a maximum rate constant increasing micelle concentration. Such rate maxima are typical of micellar catalyzed bimolecular reactions. The reaction mediated by R-$BI^{\ominus}$ in micellar solutions are obviously slower than those by $BI^{\ominus}$, and the reaction rate were decreased with increase of lengths of alkyl groups. It seems due to steric effect of alkyl groups of R-$BI^{\ominus}$ in Stern layer of micellar solution. The surfactant reagent, CTABr, strongly catalyzes the reaction of IPNPIN with R-BI and its anion(R-$BI^{\ominus}$) in carbonate buffer(pH 10.7). For example, $4{\times}10^{-3}$ M CTABr in $1{\times}10^{-4}$ M BI solution increase the rate constant($k_{\Psi}=98.5{\times}10^{-3}\;sec^{-1}$) of the dephosphorylation by a factor ca.25, when compared with reaction($k_{\Psi}=3.9{\times}10^{-4}\;sec^{-1}$) in $1{\times}10^{-4}$ M BI solution(without CTABr). And no CTABr solution, in $1{\times}10^{-4}$ M BI solution increase the rate constant($k_{\Psi}=3.9{\times}10^{-4}\;sec^{-1}$) of the dephosphorylation by a factor ca.39, when compared with reaction ($k_{\Psi}=1.0{\times}10^{-5}\;sec^{-1}$) in water solution(without BI). This predicts that the reactivities of R-$BI^{\ominus}$ in the micellar pseudophase are much smaller than that of $BI^{\ominus}$. Due to the hydrophobicity and steric effect of alkyl group substituents, these groups would penetrate into the core of the micelle for stabilization by van der Waals interaction with long alkyl groups of CTABr.

• 한국초전도ㆍ저온공학회논문지
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• 제1권2호
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• pp.15-19
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• 1999

For large scale applications of high temperature superconductor (HTS) such as transmission cables, motors and generators, long length of flexible HTS conductor is required. Currently, Bi-2223 HTS tape is capable of being fabricated in longer than 100 m length by industrial processes. In this study, we fabricated 100 m 19 filamentary Bi-2223 ($Bi_{1.8}Pb_{0.4}Sr_2Ca_2O_{10+x}$) HTS tape by PIT (Power in Tube) process. Critical current(IC) of this long length tape was measured 18.5 A at 77K, self field. Critical current of 100 m length tape was mainly resulted from the increase of inhomogeneity in oxide from the increase of inhomogeneity in oxide layer. Engineering critical current (Je=Ic/total tape cross-section area) that is important factor for practical applications and fabrication cost was measured 2.2 kA/cm2.

• Journal of Electrochemical Science and Technology
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• 제10권4호
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• pp.424-432
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• 2019

Planar BiVO₄ and 3 wt% Mo-doped BiVO₄ (abbreviated as Mo:BiVO₄) film were prepared by the facile spin-coating method on fluorine doped SnO₂(FTO) substrate in the same precursor solution including the Mo precursor in Mo:BiVO₄ film. After annealing at a high temperature of 450℃ for 30 min to improve crystallinity, the films exhibited the monoclinic crystalline phase and nanoporous architecture. Both films showed no remarkably discrepancy in crystalline or morphological properties. To investigate the effect of surface passivation exploring the Al₂O₃ layer, the ultra-thin Al₂O₃ layer with a thickness of approximately 2 nm was deposited on BiVO₄ film using the atomic layer deposition (ALD) method. No distinct morphological modification was observed for all prepared BiVO₄ and Mo:BiVO₄ films. Only slightly reduced nanopores were observed. Although both samples showed some reduction of light absorption in the visible wavelength after coating of Al₂O₃ layer, the Al₂O₃ coated BiVO₄ (Al₂O₃/BiVO₄) film exhibited enhanced photoelectrochemical performance in 0.5 M Na₂SO₄ solution (pH 6.5), having higher photocurrent density (0.91 mA/㎠ at 1.23 V vs. reversible hydrogen electrode (RHE), briefly abbreviated as V_RHE) than BiVO₄ film (0.12 mA/㎠ at 1.23 V_RHE). Moreover, Al₂O₃ coating on the Mo:BiVO₄ film exhibited more enhanced photocurrent density (1.5 mA/㎠ at 1.23 V_RHE) than the Mo:BiVO₄ film (0.86 mA/㎠ at 1.23 V_RHE). To examine the reasons, capacitance measurement and Mott-Schottky analysis were conducted, revealing that the significant degradation of capacitance value was observed in both BiVO₄ film and Al₂O₃/Mo:BiVO₄ film, probably due to degraded capacitance by surface passivation. Furthermore, the flat-band potential (V_FB) was negatively shifted to about 200 mV while the electronic conductivities were enhanced by Al₂O₃ coating in both samples, contributing to the advancement of PEC performance by ultra-thin Al₂O₃ layer.

• 공업화학
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• 제22권5호
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• pp.479-485
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• 2011

다양한 비율의 Pt와 Bi를 carbon black (Vulcan XC-72R)에 담지시킨 Pt-Bi/C 촉매를 환원법을 이용하여 합성하였다. Pt와 Bi의 전구체로는 염화백금산($H_2PtCl_6{\cdot}xH_2O$)과 비스무스트리질산($Bi(NO_3)_3{\cdot}5H_2O$) 수용액을 각각 사용하였으며, 금속을 carbon에 담지하기 전, 금속물질의 분산도를 높여주기 위해 열처리와 산처리를 수행한 carbon black을 사용하였다. XRD (X-ray Diffraction) 분석과 XPS (X-ray Photoelectron Spectroscopy) 분석을 통하여 Pt-Bi/C 촉매 내에 Pt와 Bi가 소성시키기 전에는 BiPt 혹은 $Bi_2Pt$로 존재하지만 $500^{\circ}C}$에서 소성을 한 후에는 Pt 격자구조 안으로 Bi가 침투하여 alloy을 형성하는 것을 확인하였다. 합성한 전극의 메탄올 산화반응은 전기화학분석장치(Potentiostat; Princeton applied research, VSP)를 사용하여 0.5 M $CH_3OH$와 0.5 M $H_2SO_4$의 혼합수용액에서 순환전압법(cyclic voltammetry, CV)을 이용해 측정하였다. 메탄올 산화에 대한 전기화학적 촉매 활성을 평가한 결과 적절한 양의 Bi를 첨가한 경우, 메탄올 산화반응에 대한 높은 촉매활성을 나타냄을 확인하였다. 메탄올 산화에 대한 활성은 전극과 전해질 사이의 안정성과 밀접한 관련이 있다. 정전압법(Chronoamperometry, CA)을 이용하여 전극의 안정성을 평가한 결과 메탄올 산화반응에 높은 활성을 나타내는 촉매일수록 전극의 안정성도 높은 것을 확인하였다.