• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2008년도 제31회 추계학술대회논문집
• /
• pp.459-462
• /
• 2008

슬러리 연료 제조 시 카본의 분산안정성에 미치는 공정변수의 영향을 조사하였다. 슬러리연료 저장용기의 세군데(위, 중간, 아래) 위치별로 채취된 시료에서 평균입도와 탄소함량을 분석하여 Jet A-1에서 카본의 분산안정성을 측정하였다. 여러 종류의 첨가제를 적용한 결과, NB463S84 사용 시 분산성과 증가된 중력 가속도하에서 안정성이 가장 우수하였다. 동일 조건에서 카본층 높이 변화와 카본의 평균입도 측정을 통하여 혼합장비의 성능을 비교하였고, 실험실 규모에서 얻은 제조조건을 bench 규모 제조에 적용하여 본 연구의 실용 가능성을 확인하였다.

• 전기화학회지
• /
• 제7권1호
• /
• pp.38-43
• /
• 2004

전기화학적으로 이온을 흡착시켜 제거시키는 capacitive deionization(CDI) 공정용 전극으로 탄소에어로젤에 실리카젤이 첨가된 다공성 탄소에어로젤 복합전극을 사유하여 1,000ppm NaCl수용액에서 10회와 100회 동안 싸이클을 변화시켜 탈염과 재생 특성에 대한 충전과 방전 시 시간에 따른 전류변화, 싸이클에 대한 전하량 변화, 그리고 CDI효율을 조사하였다. Paste rolling법으로 제조된 탄소에어로젤 복합전극은 CDI반응진행에 대한 전극 활물질의 탈락이 없이 전극의 성형성이 크게 향상되었고, 전극시트 제조시간을 $50\%$ 이상 단축시킬 수 있었다. 10분동안 충전과 방전으로 10회 싸이클까지의 전하량 결과를 살펴보면, $50wt.\%$의 실리카젤이 첨가된 C복합전극의 평균 충전 전하량이 실리카젤이 첨가되지 않은 A전극에 비해 $3\%$ 증가하였으며, 평균 방전 전하량은 $7\%$증가하였다. 5분동안 충전과 방전으로 100회 싸이클까지 평균 충전 전하량을 보면 $25w1.\%$와 $50wt.\%$의 실리카젤이 첨가된 B복합전극과 C복합전극은 A전극에 비해 각각 $6\%,\;14\%$증가하였으며, 또한 평균 방전 전하량도 각각 $9\%,\;21\%$증가하여 복합전극의 전하량 특성이 매우 우수하였다. 100회 싸이클까지의 CDI효율은 싸이클이 진행되면서 $70\%$ 이상으로 안정하게 유지하였고, 100회 싸이클에서는 B 복합전극이 $72.3\%$, C 복합전극이 $74.0\%$로 A 전극$(63.1\%)$보다 $10\%$이상 우수한 CDI 효율을 나타내었다.

• Toxicological Research
• /
• 제24권1호
• /
• pp.23-28
• /
• 2008

Voltammetric analysis of mercury ions was developed using paste electrodes (PEs) with DNA and carbon nanotube mixed electrodes. The optimized analytical results of the cyclic voltammetry (CV) of the $1{\sim}14ng\;L^{-1}Hg(II)$ concentration and the square wave (SW) stripping voltammetry of the $1{\sim}12ng\;L^{-1}Hg(II)$ working range within an accumulation time of 400 seconds were obtained in 0.1 M $NH_4H_2PO_4$ electrolyte solutions of pH 4.0. For the relative standard deviations of the $1ng\;L^{-1}Hg(II)$, which were observed at 0.078% (n = 15) at the optimum conditions, the low detection limit (S/N) was pegged at $0.2ng\;L^{-1}(7.37{\times}10^{-13}M)$ for Hg(II). The results can be applied to assays in biological fish kidneys and wastewater samples.

• 한국응용과학기술학회지
• /
• 제33권4호
• /
• pp.726-733
• /
• 2016

A voltammetric analysis of doxycycline was developed using DNA immobilized onto a carbon nanotube paste electrode (PE). An anodic peak current was indicated at 0.2 V (versus Ag/AgCl) in a 0.1M $NH_4H_2PO_4$ electrolyte solution. The linear working range of the cyclic and square wave stripping voltammetry was obtained to $1-27ngL^{-1}$ with an accumulation time of 800 s. Final analytical parameters were optimized to be as follows: amplitude, 0.35 V; frequency, 500 Hz; and pH, 5.43. Here detection limit was found to be $0.45ngL^{-1}$, this result can be applied in foods systems and in the biological diagnostics

• 한국표면공학회지
• /
• 제45권4호
• /
• pp.162-167
• /
• 2012

Ni-P/C multi-layer was synthesized by electroless plating and paste coating for better corrosion and surface conductance as a metallic bipolar plate. The Ni-P layer could be synthesized with the range of 2.6~22.4 at.% P contents and it's surface morphology and corrosion resistance depend on content of P. Corrosion resistance of the Ni-P layer in sulfuric acid by electrochemical test is similar with pure Ni. Surface resistance of pure Ni after corrosion was increased about 8% compared to pure Ni. On the other hand, that of the Ni-P/C composite with 20% carbon content was increased only 1%.

• 대한화학회지
• /
• 제42권1호
• /
• pp.28-35
• /
• 1998

Alga와 같은 미생물은 중금속을 흡수한다. Alga(Anabaena)로 변성시킨 탄소반죽전극으로 Cd(Ⅱ)이온을 사전농축시켜서 Cd(Ⅱ)을 양극벗김 펄스차이 전압-전류법으로 정량하였다. Cd(Ⅱ)의 산화봉우리는 -0.75V vs. SCE.에서 나타났으며, 이 봉우리를 이용하여 Cd(Ⅱ) 정량의 최적조건을 조사하였다. 변성전극의 제작에 미치는 alga양의 영향과 Cd(Ⅱ)의 사전농축에 미치는 pH와 이온세기, 온도 및 사전농축시간에 대한 영향을 조사하였으며. 전극표면에 사전 농축시킨 Cd(Ⅱ)이온을 전해환원시키는 시간과 전위의 영향도 조사하였다. Cd(Ⅱ)을 정량하기 위한 검정선은 $1.0{\times}10^6\;M ~ 8.0{\times}10^6\;M$범위에서 직선성(상관계수는0.9978)이 성립하였고 검출한계는 $5.0{\times}10^{-7}\;M$이었다. $7.0{\times}10^{-6}\;M$ Cd(Ⅱ)용액에서 얻은 상대표준편차는 3.1%(n=6)이었다. Alga변성전극의 사용횟수는 0.1M HCl 용액으로 전극표면을 재생시킬 때에 10회까지 연속측정이 가능하였다.

• 한국구조물진단유지관리공학회 논문집
• /
• 제22권3호
• /
• pp.90-96
• /
• 2018

본 연구에서는 탄소 포집 물질인 ${\gamma}-C_2S$를 함유하고 있는 Stainless Steel Slag AOD를 포함한 시멘트 페이스트의 역학적 및 미세구조 변화를 연구하였다. ${\gamma}-C_2S$는 비수경성이며 그러므로 물과 반응하지 않는다. 그러나 ${\gamma}-C_2S$는 물에 의한 탄산화 양생조건에서 반응성을 가지고 있다. 그 반응은 페이스트 안의 공극을 치밀하게 형성하기 때문에 STS-A를 사용한 시멘트 페이스트의 공극구조는 탄산화 ($CO_2$ 농도는 약 5%)후에 수은압입시험에 의해 측정될 수 있다. 또한 Fractal 특성은 시멘트 페이스트의 미세구조변화는 탄산화 영향에 대하여 연구하였다. 그 결과로부터 STS-A를 포함하는 탄산화 시멘트 페이스트는 강도가 증가하였고 공극구조는 더 치밀해졌다.

• Environmental Engineering Research
• /
• 제25권4호
• /
• pp.579-587
• /
• 2020

Novel silane grafted bentonite was obtained using the natural bentonite as precursor material. The material which is termed as nanocomposite was characterized by the Fourier Transform Infra-red (FT-IR) and X-ray diffraction (XRD) methods. The surface imaging and elemental mapping was performed using Scanning Electron Microscopic (SEM/EDX) technique. The electroanalytical studies were performed using the nanocomposite electrode. The electroactive surface area of nanocomposite electrode was significantly increased than the pristine bentonite or bare carbon paste based working electrode. The impedance spectroscopic studies were conducted to simulate the equivalent circuit and Nyquist plots were drawn for the carbon paste electrode and nanocomposite electrodes. A single step oxidation/reduction process occurred for As(III) having ΔE value 0.36 V at pH 2.0. The anodic stripping voltammetry was performed for concentration dependence studies of As(III) (0.5 to 20.0 ㎍/L) and reasonably a good linear relationship was obtained. The detection limit of the As(III) detection was calculated as 0.00360±0.00002 ㎍/L having with observed relative standard deviations (RSD) less than 4%. The presence of several cations and anions has not affected the detection of As(III) however, the presence of Cu(II) and Mn(II) affected the detection of As(III). The selectivity of As(III) was achieved using the Tlawng river water sample spiked with As(III).

• Environmental Engineering Research
• /
• 제22권2호
• /
• pp.186-192
• /
• 2017

The carbon paste electrode (CPE) was modified with the pristine bentonite and hybrid material (HDTMA-modified bentonite). The modified-CPEs are then employed as working electrode in an electrochemical detection of As(V) from aqueous solutions using the cyclic voltammetric measurements. Cyclic voltammograms revealed that As(V) showed reversible behavior onto the working electrode. The hybrid material-modified carbon paste electrode showed significantly enhanced electrochemical signal which was then utilized in the low level detection of As(V). Moreover, the studies were conducted at neutral pH conditions. The electrochemical studies were conducted with scan rates (20 to 200 mV/s) to deduce the mechanism of redox processes involved at the electrode surface. The anodic current was linearly increased, increasing the concentration of As(V) from 5.0 to $35.0{\mu}g/g$ using the hybrid material-modified electrode. This provided fairly a good calibration line for As(V) detection. The presence of varied concentrations of As(III) in the determination of total arsenic was studied. The influence of several cations and anions viz., Cu(II), Mn(II), Zn(II), Pb(II), Cd(II), Fe(III), $Cl^-$, $NO_3{^-}$, $PO_4{^{3-}}$, EDTA and glycine in the detection of As(V) from aqueous solution was also studied. Further, in an attempt to simulate the real matrix analysis, the tap water sample was spiked with As(V) and subjected for As(V) detection using the modified-CPE.

• 전기화학회지
• /
• 제27권1호
• /
• pp.15-31
• /
• 2024

The antimalarial drug hydroxychloroquine sulphate (HCQ) has taken much attention during the first COVID-19 pandemic phase for the treatment of severe acute respiratory infection (SARI) patients. Hence it is interest to study the electrochemical properties and photocatalytic degradation of the HCQ drug. Copper oxide (CuO) nanoparticles, graphene oxide (GO) and CuO/GO NC (nanocomposite) modified carbon paste electrodes (MCPE) are used for the detection of HCQ in an aqueous medium. Electrochemical behaviour of HCQ (20 μM) was observed using CuO/MCPE, GO/MCPE and CuO/GO NC/MCPE in 0.1 M phosphate buffer at pH 7 with a scan rate of 20 to 120 mV s^-1 by cyclic voltammetry (CV). Differential pulse voltammetry (DPV) of HCQ was performed for 0.6 to 16 μM HCQ. The CuO/GO NC/MCPE showed a reasonably good sensitivity of 0.33 to 0.44 μA μM cm^-2 with LOD of 69 to 92 nM for HCQ. Furthermore, the CuO/GO NC was used as a catalyst for the photodegradation of HCQ by monitoring its UV-Vis absorption spectra. About 98% was degraded in about 34 min under visible light and after 4 cycles it was 87%. The improved photocatalytic activity may be attributed to decrease in bandgap energy and enhanced ability for the electrons to migrate. Thus, CuO/GO NC showed good results for both sensing and degradation applications as well as reproducibility.